The present invention relates to electromagnetically-countered speaker systems for generating acoustic sounds according to dynamic signals supplied thereto while minimizing irradiation of harmful electromagnetic waves therefrom. More particularly, the present invention relates to various speaker systems which do not include speaker magnets but include driver members for generating the sounds while emitting such harmful waves and counter members for generating magnetic forces for providing such sound while emitting counter electromagnetic waves capable of canceling at least a substantial portion of the harmful waves based on their configurational and phase characteristics. The present invention also relates to various speaker systems which do not include speaker magnets but include various electric and/or magnetic shields in addition to such drive and counter members. The present invention also relates to various methods of minimizing irradiation of the harmful waves of the speaker systems by the counter members, various methods of shielding such harmful waves by the electric and/or magnetic shields, and the like. The present invention further relates to various processes for providing such systems, counter members thereof, and electric and/or magnetic shields therefor.

It is now well established in the scientific community that electromagnetic waves with varying frequencies irradiated by various devices may be hazardous to human health. In some cases, such electromagnetic waves in mega- and giag-hertz range may be the main culprit, whereas the 60-hertz electromagnetic waves may be the main health concern in other cases. It cannot be too emphasized that it is very difficult to shield against magnetic waves of the 60-hertz electromagnetic waves which have wavelengths amounting to thousands of kilometers and that such 60-hertz magnetic waves are omnipresent in any corner of the current civilization.
However, intensity of such electromagnetic waves typically decreases inversely proportional to a square of a distance from a source of such waves to a target. Accordingly, potentially adverse effects from such electromagnetic waves may be minimized by maintaining a safe distance from such a source. Some electrical devices, however, are intended to be used in a close proximity to an user, where typical examples of such devices are hair dryers, hair curlers, electric mattresses or blankets, heating pads, and the like. Accordingly, the Applicant have disclosed numerous electromagnetically-shielded embodiments of such devices.
In contrary to the above devices, conventional electric speakers operate with electric currents having amplitudes lot less than those flowing in such devices. However, certain speakers included in earphones, headphones, cellular phones, and handsets of regular phones are to be disposed close to an ear of an user. Accordingly, although these speakers may emit the electromagnetic waves having less amplitudes, such speakers tend to irradiate the electromagnetic waves directly to brain cells in a close proximity thereto. In particular, the earphones are to be disposed into an ear canal of the ear so that the electromagnetic waves irradiated therefrom may reach the brain cells at a less distance and, therefore, with greater strengths. It is appreciated that the irradiation of such undesirable waves may not be prevented by operating the speakers by a DC current, for such speakers generate the sounds through fluctuating electric currents which inevitably irradiate such electromagnetic waves.
Electromagnetic waves have been proved to affect physiological activities of brain cells. For example, U.S. Pat. Nos. 4,940,453, 5,047,005, 5,061,234, 5,066,272, and 5,267,938 describe various apparatus and methods for stimulating the brain cells by impinging thereto electromagnetic waves. In more recent disclosures, both of U.S. Pat. No. 6,849,040 B2 issued to J. Ruohonen et al. on Feb. 1, 2005 and U.S. Pat. Appl. Pub. No. 2003/0073899 A1 of the same inventors published on Apr. 17, 2003 disclose dose-computing apparatus and method for determining effects of magnetic stimulation on human brain. However, the prior art does not provide any speakers capable of reducing irradiation of the harmful electromagnetic waves to the brain cells of the user.
For example, U.S. Pat. No. 6,590,539 B2 issued to H. Shinichi on Jul. 8, 2003 and another U.S. Pat. Appl. Pub. No. 2002/0060645 A1 of the same inventor published on May 23, 2002 describe dipole antennas of portable communication devices capable of reducing specific absorption rate or "SAR" of electromagnetic waves (to be abbreviated as "EM waves" hereinafter) emitted by such devices. U.S. Pat. No. 6,377,827 B1 issued to N. Rydbeck on Apr. 23, 2002 describes mobile communication devices with foldable antennas which may be disposed away from users during use to reduce the EM waves propagating to the brains of the users, while U.S. Pat. No. 6,246,374 B1 issued to A. Perrotta et al. on Jun. 12, 2001 discloses antenna assemblies of mobile communication devices with main and parasitic antennas disposed away from the users for reducing the EM waves during use. In addition, U.S. Pat. No. 5,586,168 issued to B. Bucalo et al. on Dec. 17, 1996 similarly discloses multi-piece cellular communication devices including antennas disposed toward and away from the rest of such devices and reducing such EM waves emitted thereby. Although these prior art devices may reduce a portion of such EM waves, they fail to reduce the EM waves irradiated to the user from their speakers.
In another class of examples, U.S. Pat. No. 6,418,273 B1 issued to J. Lubinski et al. on Jul. 9, 2002 describes portable CD player devices incorporating less semiconductor devices and minimizing irradiation of the EM waves, while U.S. Pat. No. 6,195,562 B1 issued to R. Pirhonen et al. on Feb. 27, 2001 discloses mobile communication devices capable of restricting maximum transmitting power thereof, thereby limiting power of their EM waves radiated thereby. U.S. Pat. No. 5,777,261 issued to J. Katz on Jul. 7, 1998 discloses mobile communication devices having cases capable of attenuating and diverting their EM waves irradiated thereby, and U.S. Pat. Appl. Pub. No. 2004/0170086 A1 of Y. Mayer et al. published on Sep. 2, 2004 describes microphone devices which may not employ any membranes. U.S. Pat. Appl. Pub. No. 2003/0002691 A1 of H. Ono et al. published on Jan. 2, 2003 describes earphones for portable communication devices capable of being attached thereto at distances and reducing irradiation of the EM waves, while U.S. Pat. Appl. Pub. No. 2002/0098862 A1 of E. Engstrom published on Jul. 25, 2002 describes mobile communication devices with speakers and antennas disposed away from heads of users for reducing exposure of the users to the EM waves from the speakers and antennas thereof. In addition, U.S. Pat. Appl. Pub. No. 2001/0034253 A1 of S. Ruschin published on Oct. 25, 2001 describes mobile communication devices with speakers and microphones coupled by optical paths for reducing radiation of EM waves. Although some of these prior art devices have recognized potential hazards from their speakers, none of the prior art devices teach how to reduce the irradiation of the EM waves from the speakers of such devices.
The prior art also discloses various acoustic paths capable of delivering sounds therethrough. Thus, U.S. Pat. No. 6,825,810 B2 issued to G. Ragner et al. on Nov. 30, 2004 and U.S. Pat. Appl. Pub. No. 2003/0132884 A1 of the same inventors published on Jul. 17, 2003 describe various mobile communication devices employing air channels to route sounds from their speakers to their earpieces, while U.S. Pat. No. 6,631,279 B2 issued to A. Rivera on Oct. 7, 2003 and U.S. Pat. Appl. Pub. No. 2002/0055374 A1 by the same inventor published on May 9, 2002 disclose assemblies of speakers and microphones of cellular communication devices including air tubes for transmitting and receiving acoustic waves for reducing irradiation of the EM waves generated thereby. U.S. Pat. No. 6,377,824 B1 issued to R. Ingbir et al. on Apr. 23, 2002 describes assemblies for cellular communication devices capable of converting electrical signals to acoustic signals to reduce the irradiation of the EM waves, while U.S. Pat. No. 6,181,801 B1 issued to S. Puthuffet al. on Jan. 30, 2001 describes earpieces of mobile communication devices disposed away therefrom through connectors to reduce exposure to the EM waves emitted thereby. In addition, U.S. Pat. Appl. Pub. No. 2004/0125979 A1 of J. Elidan et al. published on Jul. 1, 2004 discloses portable communication devices including tubes for transmitting acoustic waves to and from speakers and microphones and reducing the irradiation of the EM waves, while U.S. Pat. Appl. Pub. No. 2002/0048385 A1 of I. Rosenberg published on Apr. 25, 2002 describes cellular communication devices having assemblies of speakers and microphones coupled by air tubes and receiving and transmitting acoustic waves through the tubes for reducing the irradiation of the EM waves. Though these devices may reduce the exposure of the user to the EM waves, such may be achieved by increasing distances between the user and sources of the EM waves, not by decreasing amounts of the EM waves generated by such devices. In addition, incorporation of such air channels not only introduces mechanical noises to the sounds but also mandates use of additional components such as the air channels.
Various shields have also been described in the prior art so as to shield the user from the EM waves. For example, U.S. Pat. No. 6,855,883 B1 issued to H. Matsui on Feb. 15, 2005 describes shielding materials of electrically conductive fibers woven into a web and incorporated into a case of mobile communication devices, while U.S. Pat. No. 6,708,047 B1 issued to J. Miller et al. on Mar. 16, 2004 discloses annular radiation shields disposed around antennas of mobile communication devices. U.S. Pat. No. 6,314,277 B1 issued to Y-F Hsu et al. on Nov. 6, 2001 discloses radiation shields disposed on one side of an antenna of a mobile communication device for absorbing such EM waves, whereas U.S. Pat. No. 6,184,835 B1 issued to C. Chen et al. on Feb. 6, 2001 describes shielding covers for mobile communication devices for absorbing the EM waves radiated from their antennas. U.S. Pat. No. 6,137,998 issued to H. Holshouser et al. on Oct. 24, 2000 also discloses shields for antennas of cellular communication devices for reducing the EM waves radiated to their users, while U.S. Pat. No. 5,657,386 issued to J. Schwanke on Aug. 12, 1997 describes cellular communication devices including shields incorporated into their cases and absorbing or dispersing such EM waves. U.S. Pat. No. 5,406,038 issued to D. Reiff et al. on Apr. 11, 1995 describes speakers with diaphragms coated with metal layers to prevent transmission of the EM waves therethrough, while U.S. Pat. Appl. Pub. No. 2004/0219328 A1 of K. Tasaki et al. published on Nov. 4, 2004 discloses laminates of soft magnetic materials and insulators capable of being used as countermeasures against a specific absorption rate. In addition, U.S. Pat. Appl. Pub. No. 2004/0090385 A1 of R. Green published on May 13, 2004 describes cellular communication devices with shielding and reflecting layers for reflecting the EM waves away from users, U.S. Pat. Appl. Pub. No. 2002/0137473 A1 of D. Jenkins published on Sep. 26, 2002 discloses shields disposed over speakers of mobile communication devices and obstructing the EM waves irradiated by their speakers, and U.S. Pat. Appl. Pub. No. 2002/0097189 A1 of S. Coloney published on Jul. 25, 2002 describes mobile communication devices with shields which are disposed over speakers and antennas of the devices for reducing the EM waves emitted thereby. Although these shields claim to shield the user from the harmful EM waves, such shields may amount only to electric shields capable of shielding electric waves of the EM waves and may not at all shield magnetic waves of the EM waves.
Thus, there is an urgent need for electromagnetically-countered speaker systems capable of effectively reducing the irradiation of the harmful EM waves from their speakers without affecting the sounds. There also is a need for the speaker systems employing simple countermeasures capable of canceling at least a substantial portion of the harmful EM waves irradiated by their speakers without compromising their performances as well as complicating their configurations. There is another need for such systems which may not include any permanent magnets and, accordingly, may have a lighter weight. In addition, there is need for electric and magnetic shields for such speaker systems capable of shielding users from the harmful electric and magnetic waves of the EM waves. Moreover, there is a need for speaker systems including multiple mechanisms for shielding the users from the harmful EM waves irradiated by their speakers.

Electromagnetically-countered speaker systems and methods


The present invention relates to a method for producing a footlet on a circular knitting machine including at least a first (S1) and a second knitting system (S2), wherein a first quadrant is associated with the first knitting system (S1) and a second quadrant is associated with the second knitting system (S2), including the following steps: a) knitting an access opening (12) of the footlet, wherein at least a first (B1), a second (B2) and a third region (B3) are formed in the transverse direction of the access opening (12), wherein a first (A1), a second (A2) and a third section (A3) are formed in the longitudinal direction of the access opening (12), including the following sub-steps: a1) knitting the second region (B2) and the third region (B3) of the first section (A1); a2) knitting the second region (B2) and the third region (B3) of the second section (A2); and a3) knitting the second region (B2) and the third region (B3) of the third section (A3). Moreover, the invention includes a footlet produced by the method, a programmable circular knitting machine, the programming of which is configured to perform such a method, as well as a computer program product for a circular knitting machine, which is configured to perform such a method.

Since a few years, footlets become increasingly popular. They are worn particularly willingly together with sports shoes and sneakers and offer the advantage that externally there is conveyed the impression that the wearer would wear the shoe directly on the skin, but in fact this is not the case. Rather, the wearer achieves this desired optical effect and yet achieves the advantage that there is fabric between his skin and the shoe, which absorbs sweat as well as reduces smell of sweat and friction. Thereby, a comfortable feeling of wearing with aesthetically attractive look results.
By a circular knitting machine, a knitting machine is to be understood, in which the machine constituting elements, i.e. especially needles and sinkers, are disposed circularly. In circular machine knitting, a thread is inserted into the latch needles, the needle is closed and the thread is pulled through the mesh, which was already on the needle. Subsequently, the needle is again opened and pushed upwards, i.e. expelled. The sinkers disposed between the needles, substantially have the shape of a lying U. It is their object to maintain the finished knitted meshes horizontally on the same level. The knitted fabric comes to lie in the interior of one of these Us before it is withdrawn and rolled up in the lower part of the circular knitting machine. In knitting, the needles travel standing upright in a circle. In machine knitting, a thread supply as constant as possible is important. This is accomplished by so-called thread guides in machine knitting. Of these, several are disposed topmost on the circular knitting machine corresponding to the number of threads to be processed simultaneously.
Further important characteristics of circular knitting machines are the number of the knitting systems realized thereon, the diameter of the circular knitting machine as well as the fineness thereof, i.e. for example the number of needles per inch.
In known footlets, for example, the leg termination, i.e. the access opening, is finished. Therein, first, a tube is knitted, the opening is cut out and subsequently a band including a rubber band is seamed.
In the known footlets, the circumstance it is to be considered disadvantageous that they often have the tendency to slip into the shoe with increasing wearing duration. It results in an unpleasant feeling of wearing and results in chafing due to friction, in particular at the transition footlet-foot.
The present invention relates to a method for producing a footlet on a circular knitting machine including at least a first and a second knitting system, wherein a first quadrant is associated with the first knitting system and a second quadrant is associated with the second knitting system. Moreover, it relates to a footlet having been produced by a corresponding method, a programmable circular knitting machine, the programming of which is configured to perform such a method, as well as a computer program product for a circular knitting machine, which is configured to perform such a method. By so-called footlets, in the first approximation, socks are to be understood, which lack the tubular part, which is intended to cover the lower part of the calf.
Therefore, the object of the present invention is to develop a generic method such that a footlet can be produced therewith, which has a considerably lower tendency to slip into the shoe upon wearing. Further, the object is to provide a corresponding footlet, a correspondingly programmable circular knitting machine as well as a corresponding computer program product.
These objects are solved by a method having the features of claim 1, a footlet having the features of claim 15, a programmable circular knitting machine having the features of claim 16 as well as by a computer program product having the features of claim 17.
The present invention is based on the realization that these objects can be solved if the access opening is knitted such that it is formed slit-shaped, wherein the knitting operation is to be configured such that there is provided the possibility to knit the region surrounding the slit, i.e. the actual access opening for the foot, with another thread than the surrounding knitted fabric. By this measure, then, threads can be used for the material surrounding the slit, which are in particular characterized by a higher elasticity than the threads used for the remaining knitted fabric.
By the method according to the invention, a footlet can be produced, which is characterized by an access opening as narrow as possible, which preferably is terminated by a thread with high elasticity. Thereby, a footlet is provided, which is not visible outside of the shoe and reliably counteracts slipping into the shoe. This results in superior wearing comfort, in excellent protection against chafing and in a permanently pleasant feeling of wearing.
Accordingly, in the method according to the invention, the step of knitting the access opening of the footlet, wherein at least a first, a second and a third region are formed in transverse direction of the access opening, wherein a first, a second and a third section are formed in the longitudinal direction of the access opening, includes the following sub-steps: first, the second and the third region of the first section are knitted, within which the knitting system knitting the second region engages with the knitting system knitting the third region, wherein the knitting system knitting the first region engages with the knitting system knitting the second and the third region. Subsequently, the second and the third region of the second section is knitted, within which the knitting system knitting the second region does not engage with the knitting system knitting the third region, wherein the knitting system knitting the first region engages with the knitting system knitting the second and the third region. Finally, the second and the third region of the third section are knitted, within which the knitting system knitting the second region engages with the knitting system knitting the third region, wherein the knitting system knitting the first region engages with the knitting system knitting the second and the third region.
In other words, first, the knitting systems knitting the second and the third region engage with each other, wherein the region facing the heel is knitted before the access opening. For knitting the slit-shaped access opening, these two knitting systems then do not engage with each other, and finally, for knitting the tip-side region above the access opening, then, the mentioned two knitting systems again engage with each other. The third knitting system involved in knitting the access opening knits the first region located outside of the second and the third region, i.e. in top view viewed with the tip towards the top the left side of the footlet, the sole and the right side of the footlet.
In a preferred embodiment, in which the circular knitting machine only includes a first and a second knitting system, in the first, second and third section, the knitting system knitting the first region is the second knitting system, the knitting system knitting the second region is the second knitting system and the knitting system knitting the third region is also the second knitting system, wherein the first region is knitted with a first thread type, wherein the second region is knitted with a second thread type and wherein the third region is knitted with a third thread type. This embodiment is associated with a plurality of thread guide changes, however, it already allows the performance of the method according to the invention on a circular knitting machine with only two knitting systems.
In a further preferred embodiment, the circular knitting machine includes a first, a second and a third knitting system, wherein a third quadrant is associated with the third knitting system, wherein in the first, second and third section, the knitting system knitting the first region is the second knitting system, the knitting system knitting the second region is the second knitting system, and the knitting system knitting the third region is the third knitting system, wherein the first region is knitted with a first thread type, wherein the second region is knitted with a second thread type and wherein the third region is knitted with a third thread type. This variant is characterized in that it already allows the performance of the method according to the invention on a circular knitting machine with only three knitting systems and gets along with considerably less thread guide changes with respect to the previously mentioned preferred embodiment. In particular, the circular knitting machine even has to include less thread guides.
In a particularly preferred embodiment, the circular knitting machine includes a first, a second, a third and a fourth knitting system, wherein a third quadrant is associated with the third knitting system and a fourth quadrant is associated with the fourth knitting system, wherein in the first, second and third section, the knitting system knitting the first region is the second knitting system, the knitting system knitting the second region is the fourth knitting system and the knitting system knitting the third region is the third knitting system, wherein the first region is knitted with a first thread type, wherein the second region is knitted with a second thread type, and wherein the third region is knitted with a third thread type. This embodiment gets along with a minimum of thread guide changes and thus also with a minimum of thread guides to be provided. However, it requires a circular knitting machine with at least four knitting systems.
It is preferred if in the first, second and third section, the second and the third thread type have a greater elasticity than the first thread type. By a great elasticity, a particularly secure retention of the footlet on the foot is achieved, and thus slipping into the shoe is prevented particularly reliably.
Furthermore, it is preferred if in the first, second and third section, the first, second and third region are knitted in oscillatory motion.
Preferably, within the second section, in each row, the number of meshes in the second region corresponds to the number of meshes in the third region. Thereby, a slit opening results, in which the elastic termination is formed symmetrically.
A preferred development is characterized in that at the beginning of the first sub-step for knitting the access opening, in each row, the sum of the number of meshes in the second and in the third region comprises a first number m1, and towards the end of the first sub-step a second number m2, wherein the second number m2 is less than or equal to the first number m1. If the second number m2 is actually less than the first number m1, thus, thereby, the distance over which the second and the third region are contacted with the surrounding region, i.e. connected to it, is formed particularly long, whereby a particularly secure protection against tearing-out can be provided. The footlet produced thereby is characterized by a considerably increased durability, an even better elasticity and therefore an even better wearing comfort.
Then, within the second section, in each row, the number of meshes in the second region and the number of meshes in the third region are particularly preferred m2/2.
Appropriate measures can also be provided at the upper end of the access opening. Thus, at the beginning of the third sub-step of the production of the region of the access opening, in each row, the sum of the number of meshes in the second and in the third region can comprise a third number m3, and towards the end of the third sub-step a fourth number m4, wherein the fourth number m4 is grater than or equal to the third number m3. Thereby, a correspondingly increased security against tearing-out is also provided at the tip-side end of the access opening. However, the danger of tearing-out is generally reduced there, since the instep of the foot passes substantially flat in contrast to the heel region.
Preferably, before knitting the region of the access opening, a heel of the footlet is knitted. Therein, first, a first section is knitted-on in circular movement with at least the first knitting system, and subsequently, a second section is knitted with the first knitting system by increasing and decreasing for forming the actual heel.
Furthermore, preferably, after knitting the region of the access opening, a tip of the footlet is knitted. Therein, first, a first section is knitted in circular movement with at least the first knitting system, subsequently, a second section is knitted with the first knitting system by increasing and decreasing, and finally a third section is knitted in circular movement with at least the first knitting system.
It can be provided that between knitting the first section and the second section of the tip of the footlet, a fourth section is knitted with a thread, which differs from the thread used for the first and the second section of the tip, in particular with respect to its color. Thereby, in particularly simple manner, the tip of the footlet can be identified permanently in order to exclude confusions with the heel and thus to ensure putting on of the footlet correct in side. The danger of tearing-out of the second and the third region in the region of the access opening or of tearing-in of the region, in which the knitting system knitting the second and the third region engage with each other, is considerably reduced.
Further preferred embodiments appear from the dependent claims.
The preferred embodiments presented with respect to the method according to the invention and the advantages thereof apply correspondingly, if applicable, to a footlet according to the invention, a programmable circular knitting machine according to the invention as well as a computer program product according to the invention for a circular knitting machine.

Hugo Boss Trade Mark Management GmbH & Co. KG


A heated rotary valve for use in connection with a sample to be separated in a column for heating the sample to temperature within the valve. The heated rotary valve permits introduction of compounds, having a wide boiling range, into a gas chromatograph with improved precision of area and retention time. The valve includes a stator, an elongate body, a rotor seal, a drive shaft, and an internal element for generating heat. The rotor seal may be laterally captured by a ring to prevent movement or creep due to heat absorption during operation.

1. Field
The present disclosure pertains to valves and systems for use in chromatography. More particularly, the present disclosure pertains to a heated rotary valve for use in connection with a sample to be separated in a column for heating the sample to temperature within the ports of the valve. The heated rotary valve permits introduction of a wide boiling range compounds into a gas chromatograph with improved precision of area and retention time.
2. Description of the Related Art
Gas chromatography (GC) is generally performed on a sample using a column positioned within and heated by an oven or other heating device, wherein the sample is heated before introduction to the column. The separated sample is then introduced to a detector for identification of compounds. Chromotagraphy ovens may be operated at elevated temperatures in the range of 40′ C to 400′ C. Because the column is typically a coil of thin tube, such as of metal or fused silica, with an internal polymer coating, the column rapidly reaches the ambient temperature within the oven or applied by an external heating element, which permits movement of the sample through the column. Problematically, the sample needs to be heated to the elevated temperature of the column. This is sometimes accomplished using a heated injection port where the sample size is sufficiently small, such that the injection can be accomplished using a syringe which peirces a septum—a thick, rubber disk. Heated injection ports are sufficiently hot that the sample boils and is carried into the column as a gas by helium or another carrier.
Historically, liquid injection for gas chromatography has included liquid injection by a syringe, whether split on column, but which, while simple, suffered from issues of septum lifetime and an automation system more complex that associated with a valve. The historic alternative was injection by valve, whether a one zone system such as standard liquid sample valves) or two zone injection systems, in which a sampe is moved from a cool zone, such as a sample supply, to a hot zone, such as the column. While more easily controlled and repeatable, these valve systems suffered the difficulty of ensuring the sample was at the temperature of the hot zone when reached.
Additionally, because of the large internal volumes of the valves known in the art, not only was heating unfeasible, but recycling of samples through columns repeatedly for high separation was largely only theoretical as those valves, typically using releatively large fitting adapters ( 1/16 inch or 1/32 inch, for example) introduced peak broadening in each switch, as those fittings were incompatible with small bore columns. Alternatives have included use of Dean's switching and other pressure differential methods using external solenoid valves to control the carrier gas direction. None have been highly effective for column switching.
It would be desirable to incorporate a sample which may be introduced according to a mechanically controlled system and which would be at temperature for processing through the chromatography system, but otherwise would not transfer heat or suffer from heat soak.
Additionally, in chromatography systems, it is typical that the sample may be flowed through a valve during times when no analysis is desired or ongoing. Providing a valve at an elevated temperature during those off-analyzing periods in contact with a flowing sample could be detrimental to the sample, as it could result is repeated vaporization of the sample prior to analysis.
It would therefore be desirable to provide a valve for communication with a sample source, where the valve would permit sample to flow to the column while simultaneously heating the sample to temperature for during the analysis period, but which would otherwise not introduce heat into the surrounding system or to the sample.
It would therefore be desirable to provide a valve having an internal volume of only a few nanoliters which could be used for column switching at an elevated temperature without undesirable cooling or unnecessary additional heating equipment.


In an apparatus for over-voltage and over-current protection for a step-up current-mode converter including an inductor connected via a phase node to a switch that is switched by a control signal to convert an input voltage to an output voltage, a controller has a multiplexed pin, and a resistor and a capacitor are connected in parallel between the multiplexed pin and the phase node. In an over-voltage protection mode, the controller senses the voltage on the multiplexed pin, and in an over-current protection mode, the controller supplies a current to flow through the resistor and senses the voltage on the multiplexed pin.

Over-voltage and over-current protection mechanisms are provided in a conventional step-up current-mode converter to prevent the inductor current and the output voltage of the converter from being excessive. As shown in FIG. 1, a conventional asynchronous step-up current-mode converter 100 comprises a controller 102 having a pin EXT to output a control signal S1 to switch a transistor 108 connected between a phase node 106 and ground GND, by which, when the transistor 108 turns on, an inductor current Iin is produced and flows through the transistor 108 and an inductor 104 connected between an input voltage Vin and the phase node 106, and when the transistor 108 turns off, the inductor current Iin flows through a diode 110 to charge a capacitor Co, to thereby produce an output voltage Vout. Two resistors R1 and R2 are connected in series between the converter output Vout and ground GND to divide the output voltage Vout to produce a voltage VFB fed back to a pin FB of the controller 102 so as to determine the signal S1. To prevent the inductor current Iin from being so large to damage the transistor 108, the controller 102 uses a pin CS connected to the phase node 106 through a resistor Rcs for sensing the inductor current Iin, by which, when the inductor current Iin is greater than a threshold value, the controller 102 will turn off the transistor 108 to avoid damage to the transistor 108. On the other hand, to prevent the output voltage Vout from being so high to damage the load circuit connected to the converter output Vout, the controller 102 uses a pin OVP to sense the output voltage Vout, and when the output voltage Vout is greater than a threshold value, the controller 102 will turn off the input voltage Vin or ground the converter output Vout to avoid damage to the load circuit connected to the converter output Vout.
Thus, to achieve over-voltage and over-current protection, the conventional step-up current-mode converter 100 is required two pins CS and OVP to separately sense the inductor current Iin and the output voltage Vout, and each additional pin requires more chip area and cost for the controller 102. Particularly for a multi-channel step-up current-mode converter, for example an N-channel one as shown in FIG. 2, a controller 150 therefor is required two pins OVP_J and CS_J (J=1,2, . . . , N) for each channel to achieve over-voltage and over-current protection, thus the pin count of the controller 150 increases dramatically.
Therefore, it is desired an apparatus and method to achieve over-voltage and over-current protection by utilizing fewer pins.

Apparatus and method for over-voltage and over-current protection for a step-up current-mode converter


An optical system deviation estimating apparatus includes an erected/inverted attitude setting means 9 for changing dispositional attitude of an optical system under test, a non-interferometric type wavefront measuring means 10 for measuring wavefronts at the attitudes as set up without resorting to interference phenomenon of light, a polynomial approximation means 15 for expanding measured wavefront values determined by the non-interferometric type wavefront measuring means 10 to a polynomial, an averaging arithmetic means 11 for averaging the measured values derived from output of the non-interferometric type wavefront measuring means 10 or alternatively arithmetic values derived from output of the polynomial approximation means 15, and a polynomial specific coefficient extraction arithmetic means 16 for extracting specific coefficient values of the polynomial.

A large-scale high-precision optical system destined for use and operation in the outer space has to be assembled, adjusted and evaluated on the earth or ground before being located in the outer space. In general, for the adjustment of the high-precision optical system on the ground, image forming performance or capability of the optical system concerned is measured, whereon the optical system is adjusted on the basis of the data acquired through the measurement.
A method of inspecting the high-precision optical system such as a telescope is described comprehensively, for example, in an article titled "TESTS OF OPTICAL SYSTEMS, (1) METHOD BASED ON INTERFERENCE" contained in the literature "0 plus E", No. 143, pp. 109–113. According to this known method, a collimated light beam is caused to impinge onto an optical system under test, whereon wavefront error ascribable to aberrations occurring internally of the optical system under test is measured.
As the causes or factors for the wavefront error, there can be mentioned the following.    (1) Wavefront aberration ascribable to deviation in the optical disposition of optical elements or optics in the optical system under test (hereinafter referred to as the optical system deviation or optic deviation),    (2) wavefront aberration ascribable to polishing error of optical elements or optics incorporated in the optical system under test,    (3) wavefront aberration ascribable to fluctuation of the atmosphere,    (4) wavefront aberration ascribable to gravitational deformation of the optical elements incorporated in the optical system under test, and    (5) wavefront aberration ascribable to vibration of the optical system under test and the measuring apparatus.
Of the causes or factors for the wavefront error mentioned above, the wavefront aberration (2) of high order is suppressed to a possible minimum because the optical elements are ordinarily polished to the highest degree of precision. However, the wavefront aberrations (3), (4) and (5) mentioned above make appearance because of the very measurement or test performed on the ground. Accordingly, in the case where the optic disposition is adjusted such that the measured value of the wavefront error becomes extremely small without compensating for the influences of the wavefront aberrations (3), (4) and (5), the optic deviation will take place in the optical system and the wavefront error will become remarkable as compared with the optical system which suffers no deviation, when the optical system is used or operated in the outer space.
Further, it is noted that a light source of low luminance such as e.g. an electric lamp has heretofore been employed as the light source in most of the practical applications. Consequently, image data have to be acquired by resorting to an extended-time exposure with the number of data reading times being correspondingly decreased, while minimizing the dark current of the image pickup device by cooling with a view to realizing the signal-to-noise ratio (SNR) demanded for the processing.
In general, the wavefront aberration ascribable to the fluctuation of the atmosphere is considered to vary or change temporally at random. Accordingly, the influence of the fluctuation of the atmosphere can certainly be mitigated by taking advantage of the time-integration effect which inherently accompanies the extended-time exposure. In that case, however, a lot of time is taken for each measurement, and it is difficult or impossible to analyze the time-based change rate and the period of change of the wavefront aberration ascribable to the fluctuation of the atmosphere within the time period set for the measurement.
For the reason mentioned above, optimization of the measurement environment for the fluctuation of the atmosphere on the basis of the measured data and reduction of the integration time in dependence on the measurement environment could not be realized. In particular, in the case where the non-interferometric type wavefront measuring apparatus is employed for the alignment adjustment, it is required to repeat the measurement and the adjustment at as high a rate as possible while optimizing the environment for the measurement.
On the other hand, when the source of low luminance (electric light bulb) is employed as the light source, a pin hole is used for collimating the light rays emitted from the source, and thus the light rays exiting the pin hole constitute the light source, as is known in the art. With this arrangement, the utilization efficiency of luminous energy of the light source is degraded, necessitating it to extend further the exposure time duration. Besides, it is necessary to install the light source in the main housing of the non-interferometric type wavefront measuring apparatus or in the close vicinity thereof, providing an obstacle for implementation of the main housing in small size and light weight. In addition, the influence of heat generation of the light source can not be neglected, because the wavefront aberrations are caused to change due to expansion and contraction of the main housing and the individual optical elements or optics and under application of stress, riving rise to a problem.
Furthermore, for effecting the extended-time exposure, the influence of the dark current in the image pickup device must be suppressed to a minimum. Such being the circumstances, the cooling arrangement is usually adopted particularly when the semiconductor image pickup device is employed.
However, incorporation of the cooling unit in the image pickup device will naturally result in increasing of size and weight of the main housing portion of the non-interferometric type wavefront measuring apparatus, providing an obstacle to the attempt for miniaturization of the non-interferometric type wavefront measuring apparatus. In order to cope with this problem, it is necessary to use the light source of high luminance and dispose it separately from the main housing of the non-interferometric type wavefront measuring apparatus.
By the way, in the field of the astronomical observation, there has arisen in recent years a demand for improvement of the image forming performance or image quality of the optical system. In reality, in conjunction with the reflecting telescope for the astronomical observation, efforts are being made for developing and realizing a reflecting mirror of large aperture and ideal geometrical precision with a view to making available the high-definition images of dark celestial bodies.
As a technical matter which exerts remarkable influence to the image forming performance or the image quality of the large-scale reflecting telescope such as mentioned above, there can be mentioned a so-called assembling adjustment error. More specifically, in order to ensure the prescribed image forming performance or image quality, it is necessary that deviation of relative positional relation between the reflecting mirrors falls within a predetermined range. Parenthetically, the deviation mentioned just above is referred to as the assembling adjustment error. By way of example, in the Gregory-type reflecting telescope disclosed in Tuneta-Saku's "Solar-B VISIBLE LIGHT TELESCOPE" contained in "KOKURITSU TENMONDAI NEWS (National Astronomical Observatory News)", No. 91, January 2001, the assembling adjustment error must not exceed 10 μm at the least in the arrangement in which a primary mirror having the aperture of 500 mm and a secondary mirror of a smaller size are disposed with a distance of 1500 mm therebetween. Such high degree of precision is of course difficult to realize with the assembling process which is not accompanied with adjustment. Accordingly, as a means for coping with this problem, there is adopted a method of inspecting the image forming performance of the reflecting telescope and then adjustment is so performed that the image forming performance of the reflecting telescope lies within a predetermined range.
As a method of visibly displaying the measured wavefront error, there are generally adopted a contour plotting method such as illustrated in FIG. 33 and a three-dimensional plotting method such as illustrated in FIG. 34.
Further, there is a method of displaying by plotting mode-based wavefront error components such as comma aberration, astigmatism, etc. by mathematically fitting the wavefront error to an appropriate function.
In this conjunction, it is noted that as the deviation of the relative positional relation between the primary mirror and the secondary mirror in the reflecting telescope from the design value thereof becomes greater, the plotted value of the wavefront error mentioned above become more remarkable. By repeating the assembling adjustment of the primary mirror and the secondary mirror as well as the inspection or test concerning the wavefront error described above, it is certainly possible to reduce the wavefront error to within the predetermined range.
For solving the problem mentioned above, it is required to eliminate the wavefront aberrations making appearance due to the measurement on the earth from the measured data to thereby extract only the wavefront error ascribable to the so-called optical system deviation or optic deviation and carry out the adjustment process until the wavefront error ascribable to the optic deviation becomes zero.
In particular, in the adjustment of the optic disposition with high accuracy, the wavefront error components ascribable to the factors or aberrations (3), (4) and (5) mentioned previously make appearance relatively remarkably. Thus, it is required that the wavefront measuring apparatus can ensure sufficiently large dynamic range and high measurement resolution.
Among the wavefront error factors, the aberrations (3) and (5) change temporally at random. Accordingly, it is possible to reduce the wavefront error ascribable to these factors or aberrations by resorting to a time-average processing. In that case, the wavefront error components other than those ascribable to the factors (3) and (5) can be measured with the dynamic range being enlarged.
However, in the interference measuring method adopted in the inspection of high-precision mirror surface, the wavefront error is ordinarily determined on the basis of the interference fringe produced between a reference wavefront and the measured wavefront. Consequently, the time-average processing executed upon formation of the interference fringe results in disappearance of the interference fringe.
For mathematically integrating the interference fringes, it is required to acquire once the interference fringe images and perform the summation average arithmetic operation on the images after correctively compensating for the interference fringe shifts brought about by the vibration and the fluctuation of the atmosphere. To this end, there is demanded a processing system which is capable of measuring massive interference fringe images, estimating the fringe correcting quantities and effectuating the fringe correction before summation. Besides, lots of time must be assigned to the fringe correction processing in each measurement.
As will now become apparent from the foregoing, in order to shorten the time taken for the measurement and analysis, such wavefront measuring means is demanded which is capable of correctively canceling out the wavefront error components ascribable to the factors or aberrations (3), (4) and (5) from the measured wavefront and executing the processing of extracting from the measurement data only the component ascribable to the optic disposition deviation within a short time. Further, severe requirement is imposed that magnitude of optical system deviation, i.e., optic disposition deviation, and direction thereof be estimated from the extracted wavefront error quantity to thereby adjust the reflecting telescope so that the optics or optical elements thereof assume the optimal optical disposition in the zero-gravity state.
It is further noted that according to the optical system assembling and adjusting method of the prior art, operator is required to estimate the assembling adjustment error of the optical system from the visibly indicated or plotted values of the wavefront error as described above. However, the components of the wavefront error plotted reflect the factors which depend on the environmental conditions such as temperature change, fluctuation of the atmosphere, deformation under the dead load and the like in addition to the assembling adjustment error. Consequently, there has arisen the problem that the assembling adjustment accuracy undergoes degradation in dependence on the environmental conditions.
Moreover, the assembling adjustment error contains a plurality of parameters concerning position, angle, direction and magnitude. However, difficulty is encountered in determining discriminatively these parameters on the basis of the visibly indicated or plotted wavefront error. Under the circumstances, it is necessary to repeat the adjustment and the test a large number of times, which of course means remarkable degradation in the process efficiency.
With the preset invention which has been made with a view to solving the problems mentioned above, it is contemplated as an object thereof to provide an optical system deviation estimating apparatus, an optical system deviation adjusting apparatus, an optical system deviation estimating method, and an optical system deviation adjusting method which are capable of correctively adjusting only the wavefront error ascribable to the optical system deviation and capable of measuring or inspecting the optical system destined for use in the zero-gravity environment without any appreciable difficulty on the earth.
Further, it is an object of the present invention to provide an optical system deviation estimating apparatus which can carry out inspection or test as to the assembling adjustment error of the optical system with high accuracy and at high rate without undergoing the influence of environmental conditions and which can indicate the assembling adjustment error visibly intelligibly.

Apparatus and method for estimating and adjusting deviations in an optical system based on wavefront aberrations ascribable to misalignment


A method of preparing a potassium monopersulfate composition is presented, wherein the potassium monopersulfate composition has the formula (KHSO5)x(KHSO4)y(K2SO4)z, where x+y+z=1 and x=0.46–0.64, y=0.15–0.37, and z=0.15–0.37, said potassium monopersulfate composition having an active oxygen content greater than or equal to 4.9 wt. % and K2S2O8 at a concentration of <0.5 wt. % of the potassium monopersulfate composition. The method includes reacting an H2O2 solution containing at least 70 wt. % H2O2 with a H2SO4 solution at a substoichiometric ratio of the H2SO4 to H2O2 to generate a weak Caro's acid solution, then combining the weak Caro's acid solution with oleum to produce a rich Caro's acid solution. The rich Caro's acid solution may be combined with an alkali potassium compound to produce the potassium monopersulfate composition. During the process, the temperature is maintained at below 30 ° C.

Potassium monopersulfate (KHSO5), also known as potassium peroxymonosulfate, is a component of a triple salt with the formula 2 KHSO5—KHSO4—K2SO4. Due to the high oxidation potential of potassium monopersulfate ("PMPS"), the PMPS triple salt 2 KHSO5—KHSO4—K2SO4 makes a good candidate as a component in bleaches, cleansing agents, detergents, and etching agents, and also as an oxidizing agent in inorganic reactions.
While PMPS's strong oxidation potential is well known, PMPS is limited in its utility because of the presence of an irritating byproduct, K2S2O8. The severe irritating qualities of K2S2O8 and its inherent stability relative to the desirable KHSO5 limit the use of PMPS to products that would not come in contact with its users. Thus, while PMPS could be used in personal care products, manufacturers do not use PMPS for the fear that users of these products will experience irritation from the K2S2O8. The irritating effects of K2S2O8 even limit the use of PMPS in products that come into contact with users (and their pets) indirectly, such as surface cleaners, laundry bleaching agents, and swimming pool water treatment solutions. Even low levels of K2S2O8 accumulated in pool water or laundry as residues can cause undesirable effects on humans and pets that come into contact with it. Ideally, to be able to use PMPS in these products, the level of K2S2O8 as a byproduct should be <0.1 wt. % of the PMPS.
One way to reduce or eliminate the fraction of K2S2O8 in a PMPS product is to increase the yield and stability of the desirable KHSO5 without using oleum, since the use of oleum results in the production of K2S2O8. Since a higher active oxygen content in the end product correlates with a higher fraction of KHSO5, it is desirable to achieve a PMPS composition with increased active oxygen content and higher stability using H2SO4. Publicly available Caro's acid conversion data (e.g., data from FMC Corporation) indicates that with H2SO4 to H2O2 molar ratios of 1:1 and 2:1, the active oxygen obtained from the Caro's acid equilibrium products yields 4.3% and 3.7%, respectively.
Typically, PMPS triple salt is produced by using Caro's acid (H2SO5, also called peroxymonosulphuric acid). Caro's acid is usually produced by reacting H2SO4 or oleum with H2O2. More specifically, Caro's acid is an equilibrium product between these reactants on one hand and H2SO5 and H2O on the other, as shown by the following reaction:H2SO4+H2O2<<>>H2SO5 (Caro's acid)+H2O.As the molar ratio of H2SO4 to H2O2 increases, the yield of H2SO5 increases. Thus, in order to optimize the amount of Caro's acid that is produced, excess H2SO4 or oleum is added during the process.
The Caro's acid is reacted with alkali potassium salts such as KHCO3, K2CO3, and/or KOH to generate KHSO5:H2SO5+KOH→KHSO5+H2O.Thus, increasing the yield of Caro's acid results in a higher concentration of KHSO5, which helps reduce formation of the irritant K2S2O8. The potassium to sulfur ratio (K/S) is controlled to produce a specific composition. Generally, a K/S of <1.0 will result in a high yield of KHSO5 because K/S>1.0 induces some attrition of the desired salt to produce K2SO4.
However, the salt resulting from K/S<1.0 is too unstable for most commercial applications and is hygroscopic (absorbs water). To make a stable, nonhygroscopic triple salt, a sufficient level of K/S must be achieved to produce the stabilizing sulfate salts (i.e., KHSO4 and K2SO4). In producing these compositions, the excess potassium (K/S>1.0) reacts with both KHSO5 and KHSO4, following an attrition close to their molar ratios. The decomposition of monopersulfate reduces the A.O. level in the resulting triple salt and increases sulfates.
Various parameters have been manipulated to optimize Caro's acid production. One of these parameters is reaction temperature. Temperature has been controlled to reduce the decomposition of Caro's acid, which results in release of oxygen and increase in sulfate salts, neither of which is desirable. Some knowledge regarding preparation of Caro's acid and PMPS triple salt are provided in the following references:                U.S. Pat. No. 3,939,072 ("the '072 patent") teaches a process for point of use production of Caro's acid, in which the Caro's acid is cooled to between −10° C. to 80° C. to reduce decomposition of the Caro's acid before its use.        U.S. Pat. No. 5,141,731 ("the '731 patent") teaches a process and an apparatus for point of use generation of peroxyacids by adding H2O2 to a stream of H2SO4 in multiple stages. The H2SO4 is cooled to between 15 to −40° C. before this addition. After the addition, the resulting solution is cooled to a temperature of 0 to 80° C. to reduce the decomposition of Caro's acid. The Caro's acid has to be diluted with water or used immediately thereafter, before decomposition of the Caro's acid happens. As in the '072 patent, the cool temperature is maintained to prevent A.O. loss that is generally caused by a higher temperature that results from the exothermic reaction. The resulting solution is reported to be 15% higher in H2SO5 when using multiple additions of H2O2 versus one addition. However, if the dilution with water or the use of the Caro's acid is not immediately done after the H2O2 addition, the equilibrium reaction takes place and the A.O. level rises to about 4.3. In lab experiments, Caro's acid solution is produced over a period of about 20 seconds, diluted with water to a solution strength of less than 200 g/l to stop the reactions, then chilled to preserve the Caro's acid for analysis. In practical use, the invention requires a series of stages wherein some amount of H2O2 is added to the oxyacid in each stage, mixed, and cooled.
This method illustrates that a higher percentage of H2O2 conversion can be achieved by controlling the order of addition of the reagents. However, the resulting Caro's acid solution must be used immediately after production as is the case utilizing the disclosed invention, or rapidly diluted with water in order to preserve the benefits of the invention. If not used or diluted immediately after its production, as disclosed in literature and prior art, the KHSO5 portion of the Caro's acid solution will decompose to achieve the equilibrium product that is well established in the prior art, resulting in a triple salt having an A.O. of ≦4.3.
Another shortcoming of this method is that it is difficult to implement with the use of traditional single-stage reactors. This technique requires multiple series of reactors, each independent of the other, to provide a single pass process. Naturally, this process excludes the use of traditional single-stage reactors such as batch or stirred tank reactors since addition of the H2O2 requires substantially more time to complete the addition and reaction before application or dilution whereby the reactions, including the equilibrium reaction, are sequestered.                U.S. Pat. No. 5,429,812 ("the '812 patent"), which discloses a process of producing peroxysulfuric acid from substoichiometric levels of H2SO4 to H2O2, teaches using a substoichiometric amount of H2SO4 to produce an equilibrium amount of Caro's acid. The final mixture in the '812 patent has a molar ratio of SO3 to Available Oxygen in the range of 0.8 to 0.2. The '812 patent also teaches that the order in which these reagents are introduced does not affect the Caro's acid yield. The reagents used were 70% H2O2 and 93% H2SO4. The '812 patent discloses that regardless of taking steps to avoid decomposition such as cooling and agitation, trials demonstrated that equilibrium occurred very quickly when the reactants were brought into contact, and that the position of the equilibrium depended consistently on the molar concentrations of the reactants, independently of the order of introduction.
As disclosed in the '812 patent, even with adequate cooling and agitation to prevent decomposition, the equilibrium proceeds rapidly and results with an A.O. value consistent with the established equilibrium products. This occurred regardless of the order of reactant addition and was independent of the reactant concentrations, which include H2O concentration. Also, previously, it was known that using 70% H2O2 and H2SO4 will result in a Caro's acid solution with an active oxygen content of no greater than 4.3% at a 1:1 molar ratio.                U.S. Pat. No. 5,139,763 ("the '763 patent") teaches making Caro's acid with a supra-stoichiometric molar amounts of oleum to H2O2. It discourages using H2SO4 on the grounds that a higher molar equivalent of H2SO4 is required to obtain similar yields of H2SO5 compared to oleum, resulting in a higher manufacturing cost. Also, when this high molar equivalent of H2SO4 is used, the molar ratio of the resultant solution has a H2SO5 to H2SO4 ratio that is less than what is desired for the preparation of the PMPS triple salt. The Caro's acid is partially neutralized to raise the K/S to 1.15–1.25, then combined with a solution richer in monopersulfate.
The method of the '763 patent involves many steps and results in an undesirably high concentration of K2S2O8.                U.S. Pat. No. 5,607,656 ("the 656 Patent") describes a process for producing PMPS with high available oxygen and a low concentration of K2S2O8. This process involves reacting 20 to 70 wt. % strength oleum with 30 to 70 wt. % strength hydrogen peroxide to form Caro's acid, partially neutralizing the Caro's acid, then adding sulfuric acid and potassium hydroxide to the mixture by injection into the vacuum crystallizer while evaporating off the moisture. The resulting wet salt has a K2S2O8 concentration of less than 1.5 wt. %, which is reported to be less than that found in the commercially available triple salt. However, the commercial advantage of this process is limited by the increase in cost associated with all the additional reagents (higher SO4 to H2O2 molar ratio) required to dilute the K2S2O8 concentration in the triple salt, and the resulting A.O. as compared to the initial Caro's acid solution.
The '656 patent discloses a process for producing a triple salt with reduced oxodisulfate by reacting Caro's acid produced from oleum with additional H2SO4 and KOH. This dilution process utilizes established processing techniques as previously disclosed. Like other disclosures, the critical chemistry and control parameters are met to produce the resulting triple salt.                U.S. Pat. No. 4,579,725 ("the '725 patent") describes a process for producing PMPS with high available oxygen and low K2S2O8 by partially neutralizing the Caro's acid produced from 65–75% oleum and H2O2 by reacting the reagents at a sulfur to peroxide molar ratio of 0.9 to 1.2. The Caro's acid is reacted with KOH to achieve a K/S ratio <0.95. The resulting slurry is concentrated by using vacuum evaporation so that the fraction of the slurry solids is sustained at <40%. The mother liquor that is rich in KHSO5 is recycled back to the evaporator. MgCO3 is aggressively added to the concentrated slurry to control the K/S ratio to yield a product of high A.O. The MgCO3 treatment is needed because the product has low-K/S product has low stability and melting point.
The '725 patent uses 65–75% oleum to produce Caro's acid, performs partial neutralization with KOH solution to achieve K/S ratio <0.95, concentrates using vacuum evaporation to slurry solids of <40%, forms a wet cake while returning concentrate back to the evaporator, adds MgCO3 to the cake, mixes and dries, and adds more MgCO3.
The resulting monopersulfate salt from the low K/S ratio is hygroscopic and unstable. Coating with MgCO3 was shown to stabilize the salt. MgCO3 has been used as an anti-caking agent to improve fluidity of the triple salt for many years.                U.S. Pat. No. 4,610,865 ("the 865 Patent") discloses a process to produce and concentrate a solution containing KHSO5 to a monopersulfate concentration of 20–30 wt. % KHSO5, cooling a partial stream to <15° C. to precipitate the triple salt, filtering the triple salt, and drying.
Like the '725 patent, the '865 patent defines specific chemical and control parameters like those disclosed in the expired prior art patents mentioned above, to produce a composition of triple salt precipitated from a solution of KHSO5 using a cold precipitation technique. The equipment and methods of producing the Caro's acid, triple salt, concentrating and separating are consistent with previously disclosed methods of processing.
The resulting monopersulfate, like that in the '725 patent, is produced from substoichiometric levels (excess sulfuric acid) of potassium to sulfur, and therefore is hygroscopic and exhibits poor shelf life.
All of the disclosed methods of producing a stable, non-hygroscopic (K/S>1.15) triple salt of reduced K2S2O8 with high active oxygen (>4.7%) require additional treatment of the slurry streams, reprocessing of solutions of triple salt to dilute the K2S2O8, and/or additional treatment steps to increase stability and melting point of the resulting triple salt. In doing so, waste streams of discarded inert salts such as K2SO4, and/or multiple processing steps, high recycle rates, and elaborate process control scenarios are proposed.
Because of the indirect nature of producing these hybrid triple salts, their commercial viability is severely impaired due to the increased production cost resulting from product waste (discarded salts) and/or extensive recycling and reprocessing of the triple salt solutions.
Thus, the search for a way to efficiently produce PMPS triple salt with less irritant byproducts (e.g., K2S2O8) and higher active oxygen with a high stability at a reasonable cost continues.

Potassium monopersulfate triple salt with increased active oxygen content and substantially no K2S2O8


The method of displaying chemical growths and employing structure having a first portion to contact a solution capable of forming the growths when the solution is dried, the structure also having an intermediate portion to feed the solution by wicking action from the first portion, and the structure also having a display portion to which the solution is fed from the intermediate portion and on which the growths form when the solution is fed thereto and dried, the improvement that includes modifying at least one of the portions to control the feeding of the solution.

This invention relates generally to chemical growth displays, and more particularly concerns modifying or controlling the formation of decorative chemical growths on display objects.
In my U.S. Pat. No. 4,196,239, I have disclosed a unique method and means for effectively and ornamentally displaying plant-like chemical growths, as for example on simulated vegetation, such as plants, trees, etc. There is need for modifying or controlling such chemical growths, as for example preventing or blocking growth on certain areas of the display object, and accelerating growth formation on the display object. Other type modifications are also needed and contemplated herein.


A marine outboard engine is disclosed which comprises a drive unit, a tilt/trim/steering subsystem and a stern bracket adapted for connection to an associated watercraft. The tilt/trim/steering subsystem connects the drive unit to the stern bracket and comprises a first rotary actuator carrying the drive unit for pivotal movement about a steering axis that extends generally vertically, and a second rotary actuator connected to the first rotary actuator and supporting the first rotary actuator and the drive unit for pivotal movement about a tilt/trim axis that extends generally horizontally.

A marine outboard engine generally comprises a stern bracket assembly that is fixed to the stern of a hull (boat) and to an outboard engine main unit incorporating an internal combustion engine, propeller and the like. The marine outboard engine is typically designed so that the steering angle and the tilt/trim angles of the outboard engine relative to the stern brackets (i.e. the steering angle and the tilt/trim angles relative to the boat) can be adjusted and modified as desired. The stern bracket assembly typically includes a swivel bracket carrying the outboard engine for pivotal movement about a steering axis that extends generally vertically, and a clamping bracket supporting the swivel bracket and the outboard engine for pivotal movement about a tilt axis extending generally horizontally.
Known tilt-trim subsystems typically comprise a tilt cylinder unit for swinging a swivel bracket through a relatively large angle to lift the lower portion of the outboard engine above the water level or, conversely, lower the outboard engine below the water level. Such subsystems may further comprise a distinct trim cylinder unit for angularly moving the swivel bracket through a relatively small angle to trim the outboard engine while the lower portion thereof is being submerged. One desirable characteristic of a tilt-trim subsystem would be to provide a slower rate of rotation during trimming to retain the propulsion unit in water for a longer interval during movement thereof through a predetermined angular trim range and thereafter to more rapidly elevate the propulsion unit from the water so as to reach a full tilt-up position. Unfortunately, previous tilt-trim subsystems, as suggested above, may require use of distinct tilt and trim cylinder units or have required use of fairly complex mechanical structures to somewhat meet the tilt-trim requirements of the propulsion unit. Previous subsystems have typically been bulky and cumbersome.
Therefore, there is a need for a tilt-trim and steering subsystem for a marine outboard engine that alleviates some of the drawbacks of prior art systems.

Integrated tilt/trim and steering subsystem for marine outboard engines


In conjunction with a pressurized water reactor (PWR) and a pressurizer configured to control pressure in the reactor pressure vessel, a decay heat removal system comprises a pressurized passive condenser, a turbine-driven pump connected to suction water from at least one water source into the reactor pressure vessel; and steam piping configured to deliver steam from the pressurizer to the turbine to operate the pump and to discharge the delivered steam into the pressurized passive condenser. The pump and turbine may be mounted on a common shaft via which the turbine drives the pump. The at least one water source may include a refueling water storage tank (RWST) and/or the pressurized passive condenser. A pressurizer power operated relief valve may control discharge of a portion of the delivered steam bypassing the turbine into the pressurized passive condenser to control pressure in the pressurizer.

The following relates to the nuclear power generation arts, nuclear reactor safety arts, nuclear reactor control arts, and related arts.
During normal operation of a nuclear reactor, the nuclear chain reaction (and hence the thermal output of the reactor) is controlled to maintain temperature and pressure of the coolant water in the reactor pressure vessel in a normal range. This control is achieved using mechanisms such as a control rods system, control of steam generator feed water flow, adjusting a concentration of soluble boron neutron poison in the coolant water, or so forth.
The steam generator acts as the heat sink for the nuclear reactor. If a pipe rupture interrupts feed water flow into the steam generator or steam flow out of the steam generator, a feed water flow is lost, or so forth, this heat sinking is compromised. In such a loss of heat sinking event, pressure and temperature of the coolant in the reactor pressure vessel rise, and this must be counteracted to maintain the nuclear reactor in a safe condition.
To this end, the control rods are inserted (scrammed) to extinguish the nuclear chain reaction. However, the reactor core continues to output residual heat due to radioactive intermediate products of the nuclear chain reaction. Passive cooling systems reliant on a closed-loop evaporation/condensation cycle may be employed to remove this residual heat.
If the passive cooling systems are unable to keep up with the residual heat output from the shut-down reactor core, then the temperature and pressure of the coolant inside the pressure vessel will continue to rise. In this circumstance, an emergency core cooling system (ECCS) is brought online to depressurize the pressure vessel by venting (into a suitable condenser, or into the surrounding radiological containment structure, or other suitable structure) while maintaining sufficient water flow into the reactor pressure vessel to avoid exposure of the nuclear reactor core.

PWR decay heat removal system in which steam from the pressurizer drives a turbine which drives a pump to inject water into the reactor pressure vessel


‘Matilda’ is a new and distinct waxflower plant (interspecific Chamelaucium hybrid) notable for its early flowering, compact growth habit, and dense terminal cover of large white flowers that age to white with a diffuse magenta to maroon ring.

'Matilda' is a new waxflower plant that originated as a seedling produced in a sexual breeding program conducted by the State of Western Australia at its Medina Research Station and at its South Perth nursery and laboratories. Originally identified by its breeder's reference 'WX47', 'Matilda' was selected from seedlings of a controlled cross performed in 1999 between female parent '5001/720-8', an intraspecific hybrid within C. uncinatum (not patented), and male parent C. megalopetalum 'CM 6.6' (not patented). 'Matilda' was first asexually propagated at South Perth in 2002 from cuttings, and has been shown to remain true to type over successive generations.
'Matilda' is distinguishable from its female parent '5001/720-8' by a number of features, as described in Table 1 below:
TABLE 1Characteristic'Matilda''5001/720-8'Leaf sizeMediumLongLeaf shapeNarrow ovate with acute apexLanceolate with hookedapexLeaf crossTriangular withTeretesectionindented upper surfaceFlower colorWhite aging to whiteAlmost white aging towith distinct deep magentapinkto maroon ringFlower sizeLargeSmall
'Matilda' is distinguishable from its male parent 'CM 6.6' by a number of features, as described in Table 2 below:
TABLE 2Characteristic'Matilda''CM 6.6'Growth habitCompactMedium uprightLeaf shapeNarrow ovate with acute apexObovate with obtuseapexFlower shapeOpenCuppedFlower colorWhite aging to whiteWhite aging towith distinct deep magentamagenta and maroonto maroon ringspots and uneven patchesFlower sizeLargeSmall
'Matilda' is also distinguishable from other known waxflower varieties. A comparison of 'Matilda' to 'Bridal Pearl' (unpatented), the most similar variety of common knowledge, is set forth in Table 3 below:
TABLE 3Characteristic'Matilda''Bridal Pearl'Growth habitCompactMedium uprightLeaf shapeNarrow ovate with acute apexObovate with obtuseapexFlower shapeOpenCuppedFlower colorWhite aging to white withWhite aging to magentadistinct deep magenta toand maroon spots andmaroon ringuneven patchesFlower sizeLargeMedium

Western Australian Agriculture Authority


To optimize training data used by a predictive real-estate valuation model, a search space having multiple dimensions may be defined. Each search dimension corresponds to a range of candidate values for a search criterion for selecting subsets of sales-transaction records. The multiple dimensions include a temporal dimension and a geographic dimension. An accuracy-optimized subset of a multiplicity of sales-transaction records is identified by evaluating points that vary along each dimension within the multi-dimension search space. A statistical measure of model accuracy is used to evaluate each candidate point. The accuracy-optimized subset of the multiplicity of sales-transaction records is provided to a predictive model to generate an automated value prediction for a subject real-estate property as of an effective date.

Automated valuation model ("AVM") services provide real estate property value predictions using a mathematical predictive model and a set of "training data" describing values of other properties, typically including sales data from recent property sales within a geographic region. Some AVM services also take into account previous surveyor and/or assessor valuations, historical house price movements, user inputs (e.g., number of bedrooms, property improvements, etc.) and the like.
In many cases, the accuracy of a given predictive model may depend to a large extent on the training data provided for use by the model. Typically, training data is selected from a database containing a very large number of records describing real-estate property sales across a large region, such as a country, state, county, or the like, and across a large period of time, such as many years.
Previously known methods for performing automated valuations in general, and more particularly for selecting a set of training data for a subject real-estate property are described in U.S. Pat. No. 5,361,201, which is hereby incorporated by reference, for all purposes. Such previously known methods include establishing a fixed period of time (e.g. from zero to two years prior to an effective date) and expanding or contracting a geographic boundary until a desired count of sales records are selected.
For example, to select training data according to a previously known method, a sales-transaction database may be queried to identify sales-transaction records corresponding to real-estate property sales that took place within two years prior to an effective date and within a geographic search radius of (for example) one km of a subject real-estate property. Those records are counted, and if the count is below a predetermined threshold (e.g., 100 sales transactions), the geographic search radius may be iteratively increased until the count reaches the predetermined threshold.
However, merely targeting a predetermined count of sales transactions may not result in the selection of an optimal set of training data. Consequently, there is a need for an improved method of selecting training data to provide more accurate value predictions.

Automated-valuation-model training-data optimization systems and methods


A remaining battery life measuring device may include a first estimator configured to estimate a state of charging of a battery using an open circuit voltage of the battery; a second estimator configured to estimate the state of charging of the battery using charge, discharge, or charge and discharge currents of the battery; a correction unit configured to generate a correction value on the state of charging estimated by the second estimator, based on the state of charging estimated by the first estimator or an output state of charging; and/or a state of charging (SOC) processing unit configured to calculate the output state of charging using the state of charging estimated by the second estimator and an accumulated correction value. The accumulated correction value may be generated based on the correction value.

1. Field
Some example embodiments may relate to devices and/or methods of measuring battery time remaining. Some example embodiments may relate to devices and/or methods of measuring battery time remaining by estimating the amount of charge in batteries.
2. Description of Related Art
Mobile electronic devices such as a cellular phone, a notebook computer, a portable game machine, an e-book terminal, and so on may be powered by a battery. Also, an electric vehicle using a battery engine operated by electrical energy from a battery may be becoming more common. In general, since a battery stores a limited amount of charge, it may supply power during the limited period of time.
If a battery is discharged, a mobile electronic device and an electric vehicle may not operate. If a battery is over-discharged, a life of the battery may be shortened. Thus, the mobile electronic device and the electric vehicle may measure a battery time remaining in real time to display a measured result to a user. The user may check the battery time remaining, use functions of the device selectively according to the battery time remaining, or charge the battery. Thus, it is required a technique of measuring a battery time remaining as accurately as possible. In particular, since an electric vehicle uses power of a battery, it is very important to measure a battery time remaining as accurately as possible.

Measuring devices of remaining battery life and measuring methods thereof


A building entrance protector assembly for telecommunication lines. The building entrance protector has a housing in which is disposed a splice chamber. Coaxial apertures are formed on opposing walls of the splice chamber, thereby providing a passage through the splice chamber through which a grouping of wires can pass. A plurality of posts are disposed within the splice chamber. The posts terminate at a predetermined height within the splice chamber that is above the axis of the coaxial apertures. A bracket is provided that is sized to fit within the splice chamber. The bracket is adapted to rest upon the posts. The posts therefore support the bracket above the axis of the coaxial apertures in the splice chamber. A wire connector is supported by the bracket. Accordingly, the posts and bracket act together to support the wire connector above the axis of the coaxial apertures. This ensures that the presence of the wire connector will not interfere with wires passing through the splice chamber between the coaxial apertures.

1. Field of the Invention
The present invention relates to building entrance protectors for telecommunication lines. More particularly, the present invention relates to the connector structure contained within the building entrance protector that connects outside plant wiring to customer premises equipment.
2. Description of the Prior Art
Building entrance protector (BEP) is the name used in the art of telephone equipment to describe the junction box where telephone lines from outside plant wiring are joined to customer premises equipment. In the most common application, the BEP is the place where the telephone lines from a telephone pole enter a building and are joined to the telephone system within that building. Within the BEP there is an input wire termination device that receives the telephone lines contained within the outside plant wiring. Also contained within the BEP is an output wire termination device that receives the telephone lines required for the customer premises equipment. Located in between the input wire termination device and the output wire termination device are fusible links. The fusible links are typically 26 gauge copper wire, which is thinner than the gauge of either the outside plant wiring or the customer premises equipment.
The purpose of the fusible links is to prevent power surges from passing through the BEP that can damage equipment located within the building or melt any wire on the customer side of the BEP. Since telephone lines are typically strung on the same poles as power lines, a break in a power line that subsequently contacts a telephone line, can result in a large surge of power passing through the telephone lines into a building. Similarly, lightning strikes can result large surges of power pass in through telephone lines into a building. The purpose of the BEP is to ensure that any such power surge is stopped at the point of the BEP and is prevented from traveling into the building where it can cause damage to equipment and possibly a fire.
Referring to FIG. 1, a schematic is shown illustrating a common application of BEPs 10 in a building 12. Commonly, a building 12 may have more telephone lines 14 than are capable of being connected to a single BEP 10. Consequently, it is common for a building 12 to utilize a series of BEPs 10. The outside plant wiring 16 enters a building 12 and is directed into a first BEP 10. The first BEP 10 is then used to connect some telephone lines contained within the outside plant wiring 16 to some of the customer premises equipment 18. Any telephone lines contained within the outside plant wiring 16 that are not utilized in the first BEP 10 are passed through the first BEP to a second BEP. Similarly, any telephone lines contained within the outside plant wiring 16 that are not utilized in the second BEP are passed through the second BEP to subsequent BEPs. The number of BEPs 10 used is dependent upon the number of telephone lines supplied by the outside plant wiring 16 and the needs of the customer premises equipment.
Referring to FIG. 2, it can be seen that as the outside plant wiring passes 16 into a BEP 10, the outside plant wiring 16 passes into a sealed, fire-resistant splice chamber 20. Within the splice chamber 20, some of the telephone wires 22 contained within the outside plant wiring 16 are joined to a grouping of fusible links 24. Each set of the fusible links 24 leads to a different surge protector port 26 on a surge protector panel 28. The different surge protector ports 26 are coupled an output wire termination device 30. The customer premises equipment 18 (FIG. 1) connects to the output wire termination device 30, thereby completing the link between the outside plant wiring 16 and the customer premises equipment 18 (FIG. 1).
The fusible links 24 connect to the telephone lines 22 of the outside plant wiring 16 in a number of different ways. Individual wires can be separately joined. However, such connections are highly labor intensive and time consuming. The preferred interconnection mechanism 32 is a terminal array connector 34, such as the model S 66 M connector manufactured by the Siemens Company. With such terminal array connectors 34, the fusible links 24 are connected to the terminal leads on the bottom of the terminal array connector 34 and the telephone wires 22 from the outside plant wiring 16 are connected to the terminal leads on the top of the terminal array connector 34.
All connections between the outside plant wiring 16 and the fusible links 24 are performed within the confines of the splice chamber 20. As a result, any interconnection mechanism 32 used to join the fusible links 24 to the outside plant wiring 16 must also be contained within the splice chamber 20. As a terminal array connector 34 is mounted within the splice chamber 20, there is often an interference between the body of the terminal array connector 34 and the segment of the outside plant wiring 16 that passes through the splice chamber 20 to another BEP. The outside plant wiring 16 that passes through the BEP 10 must be bent around or over the terminal array connector 34. As a result, it is not uncommon for the passing wires of the outside plant wiring 16 to become pinched by the terminal array connector 34 or chafe against the terminal array connector 34. This often causes different telephone lines to either break or short.
Additionally, since the passing wires of the outside plant wiring 16 and the terminal array connector 34 are held at close quarters within the splice chamber 20, when a fusible link 24 does melt, the heat from that melting may also melt some of the passing wires of the outside plant wiring 16. Consequently, a melted fusible link 24 in one BEP may damage a wire that terminates in a different BEP. This makes troubleshooting difficult for repair technicians.
A need therefore exists in the art for a BEP where the interconnection between outside plant wiring and the fusible links can be kept safely away from the wires of the outside plant wiring that pass through that BEP to subsequent BEPs.

Splice chamber and connector assembly for a building entrance protector


The past record of the synaptic weight values set in the learning of a neural network is stored in a weight record memory. The past stored in the weight record memory is supplied to a control unit. If there exists a synaptic connection representing a record of weight values which have been used in a predetermined number of learning processes just prior to the present learning process and which satisfy a predetermined condition, the synaptic weight value used in the succeeding learning processes for the synaptic connection is re-set to a predetermined value by a weight setting unit. That is, the past record of the synaptic weight values is monitored, and the synaptic weight value which has been set in a learning process can be re-set as required.

1. Field of the Invention
The present invention relates to a neural network in which, when learning is performed, the value of a synaptic weight can be externally and forcedly re-set.
2. Description of the Prior Art
In recent years, a multi-layer neural network in which the learning is performed by the error back-propagation learning method has been utilized in a field of speech or character recognition. A neural network usually used in such a field is of a multilayer perceptron type, typically, the three-layer perceptron type. As shown in FIG. 2, a three-layer perceptron type neural network comprises an input layer 21, an intermediate layer 22, and an output layer 23.
Units 25 in the input layer 21, units 26 in the intermediate layer 22, and units 27 in the output layer 23 are synaptically connected so as to constitute a network. When data are input into the units 25 of the input layer 21, data in accordance with the configuration of the network are output from the units 27 of the output layer 23. Each of these units comprises a portion for receiving data input from another unit, a portion for converting the input data based on a predetermined rule, and a portion for outputting the converted result to a unit which constitutes the upper layer. To a synaptic connection between the units, a weight indicative of the connecting strength is applied. Hereinafter, such a connection weight is referred to as "a synaptic weight". If the value of the synaptic weight is changed, the configuration of the network changes so that the network outputs a different output value for the same input data.
The learning of the neural network is carried out as follows. Learning data which belong to a known category are input into the units 25 of the input layer 21, and teaching data or target indicative of the category to which the input data belong are supplied to the units 27 of the output layer 23. The synaptic weights are set so that the units 27 of the output layer 23 output the same data as the teaching data. Generally, such learning is performed by the error back-propagation learning method.
When data representative of the feature pattern of an object to be recognized are input into the units 25 of the input layer 21, the thus learned neural network outputs data representative of a category to which the input data belong, from the units 27 of the output layer 23. Accordingly, based on the category represented by the output data, the category to which the input data (i.e., the feature pattern) belong can be accurately identified.
Since the number of the units 26 of the intermediate layer 22 in the above-mentioned three-layer perceptron type neural network is determined by trial and error, the number of units of the intermediate layer 22 is generally set to be substantially larger than a number which may be necessary for achieving a required recognition accuracy. As a result, the calculation time period for the entire neural network is longer, or some of the units do not affect the learning or recognition. This causes a problem in that the efficiency in the learning or recognition is decreased.
The inventor and Mr. Togawa have proposed an apparatus for controlling the learning of a neural network (Japanese Patent Application No. 1-52684 which is now published as Japanese Patent Publication (Kokai) No. 2-231670 and U.S. patent application Ser. No. 07/486,165 filed on Feb. 28, 1990) now U.S. Pat. No. 5,195,169, which is shown in FIG. 4. This proposed apparatus comprises a monitor 4 which monitors the progress of the learning in the neural network, as shown in FIG. 4. In FIG. 4, units in the respective layers, connections between respective units, synaptic weights Wd and Wu, input data, and output data of the three-layer perceptron type neural network of FIG. 2 are shown in a simplified manner.
In this system, a synaptic weight Wd is applied to the synaptic connection of each of the units in the intermediate layer 22 which are connected with all of the units in the input layer 21, and a synaptic weight Wu is applied to the synaptic connection of each of the units in the output layer 23 which are connected with all of the units in the intermediate layer 22. The monitor 4 receives: the values of the synaptic weights Wd and Wu; output data from each of the units in the output layer 23; and teaching data, and monitors the values of the synaptic weights Wd and Wu in the learning process of the neural network. For example, in the cases where units not affecting the learning exist when the learning is nearly converged, where units exhibiting a similar synaptic weight exist when the learning is nearly converged, or where units exhibiting a similar synaptic weight when the learning is not converged, the values of the synaptic weights Wd and Wu corresponding to these units are set to zero. Thus, the learning efficiency can be increased, and the number of units in the intermediate layer 22 can be modified to the optimum number, so that the optimum configuration of the neural network is established.
In short, in the above-mentioned apparatus, the values of the synaptic weights Wu and Wd are monitored, and the values of the synaptic weights Wu and Wd are set to zero. In such an apparatus, however, the values of the synaptic weights Wu and wd which can be monitored by the monitor 4 are limited to those of the synaptic weights Wu and Wd at a certain learning point. Accordingly, the existence of units which do not affect the learning or which exhibit a similar synaptic weight value is judged based on the values of the synaptic weights Wu and Wd at the present learning point.
Practically, the progress of the learning is indicated by the combination of the values of the synaptic weights Wu and Wd at an interested learning point and the past record of the values of the synaptic weights Wu and Wd. Accordingly, there arises a problem that the progress of the learning cannot be appropriately judged by the values of the synaptic weights Wu and Wd at a certain learning point.

Apparatus for changing individual weight value of corresponding synaptic connection for succeeding learning process when past weight values satisfying predetermined condition


This invention provides a mechanism for minimizing the switching time degradation of MTCMOS circuits while at the same time minimizing the area overhead due to the MTCMOS switch circuitry. This optimization is achieved by scheduling the current flow, due to the switching events of the MTCMOS logic cells, such that only temporally mutually exclusive currents, or currents whose cumulative sum is less than a predetermined value, can flow in any given switch cell. Techniques for current event merging and current event culling, and techniques for handling timing and current variances may be used.

1. Field of the Invention
The present invention relates to an integrated circuit design automation system for designing power-efficient integrated circuits. In particular, the present invention relates to a method used in conjunction with an integrated circuit design automation system that optimizes a power-efficient integrated circuit design by connecting appropriately placed and sized power-gated devices.
2. Discussion of the Related Art
In the advanced fabrication processes developed recently, the size of leakage currents1 has increased substantially over that of previous fabrication processes. Large leakage currents are detrimental in particular to battery-operated devices, such as cellular telephones and other wireless devices, which spend a substantial amount of time under stand-by operation conditions. To reduce power consumption during stand-by operations, many design techniques have been developed to minimize leakage current in an integrated circuit. One such technique, for example, is the "power-gating" technique, which is applicable to multi-threshold CMOS ("MTCMOS") circuits. An MTCMOS circuit includes transistors of different threshold voltages. Specifically, the higher threshold PMOS and NMOS transistors are used as "switch" or "sleep" transistors, each of which selectively connects or disconnects its associated physical power supply (i.e., the power supply voltage or the ground reference voltage for the integrated circuit) to and from its associated CMOS logic circuits, which are built out of lower threshold voltage transistors for higher performance. (The physical power supplies are also referred to as primary or global power supplies.) In that application, the CMOS logic circuits are each connected in series to the ground reference voltage by one or more NMOS transistors and to the power supply voltage by one or more PMOS transistors. The voltage at a source terminal of a switch transistor is referred to as a "virtual power supply" to distinguish it from the physical power supplies of the integrated circuit. While this circuit configuration significantly reduces leakage currents, power-gating presents design challenges not seen in non-power gated integrated circuit designs. One challenge, for example, relates to the area overhead introduced by the switch transistors. Another challenge relates to the electrical effects introduced by the connecting logic circuit in series with switch transistors. 1 A leakage current is the actual current load in a device when the device is in the non-conducting state.
To minimize area overhead, switch transistors are often shared among multiple MTCMOS logic cells. While sharing switch transistors reduces silicon area, significant timing issues may arise that require extensive timing analysis and delay calculation to ensure proper operation. The timing issues result from the switching time degradation in a CMOS logic circuit when the CMOS logic circuit is powered through a switch transistor connecting it to the ground reference (i.e., the effective resistance to ground seen by the discharging load capacitor is increased). The extent of the switching time degradation depends on both the size of the switch transistor and the current in the switch transistor when the logic circuit switches. Thus, it is desirable to minimize both the resistance and the current in the switch transistor. Reducing the number of logic circuit transistors sharing a switch transistor reduces switching time degradation, but increases silicon area.
There is thus a need for a design method that maximizes switch transistor sharing while simultaneously avoiding switching time degradation.

Current scheduling system and method for optimizing multi-threshold CMOS designs