A DC offset cancellation apparatus in a time division duplexing mode direct conversion receiver is disclosed that cancels DC offset of a present frame by using DC offset information of a previous frame by using a receive time difference between data transmission frames. Therefore, the DC offset cancellation unit has advantages of canceling the DC offset in an active mode in real time, of canceling the DC offset varying depending on time and circumferential conditions, and of minimizing power consumption by using an optimized element alignment.

1. Field of the Invention
The present invention relates to a DC offset cancellation apparatus, and more particularly to a DC offset cancellation apparatus in a time division duplexing mode direct conversion receiver.
2. Description of the Related Art
In general, a receiver of a communication apparatus generates DC offset. Such DC offset distorts an amplitude of a received signal so that an undesirable signal is received. At this time, if a signal received in the receiver is large, distortion of the signal may cause a receiving function of the receiver to stop. Also, such amplitude distortion causes the receiver to have an erroneous RSSI (Received Signal Strength Indicator) so that the amplitude distortion also exerts an influence when controlling an output of a transmitter. As a result, it is necessary to cancel the DC offset of the receiver.
Usually, the DC offset of the receiver is canceled by using AC-coupling or by repeatedly performing charge or discharge in TDMA (Time Division Multiple Access). In the former, i.e. using the AC-coupling, when canceling the DC offset by means of a high-pass filter, it is possible to lose near-DC information. It is known that the latter, i.e. repeatedly performing charge or discharge in TDMA, is not suitable for canceling the DC offset generated by re-radiation through an antenna in an active mode.
Also, a conventional offset cancellation technique is realized by using a mean value, a measurement unit, an auto gain controller (AGC) value, an integrator and so forth, in such a manner that the offset cancellation can be used for the active mode regardless of either a Frequency Division Duplexing (FDD) mode (i.e., CDMA 2000-Qualcomm) or a Time Division Duplexing (TDD) mode. However, this conventional offset cancellation technique increases a chip area and power consumption because it requires use of such various digital elements.
Also, conventional DC offset cancellation techniques in a digital domain cannot deal with re-radiation, which randomly varies depending on time (the number of clock cycles) required for calculating the mean value. Furthermore, if the time for calculating the mean value is extended, the conventional DC offset cancellation technique can lose a real-time characteristic of detection and correction. Conventionally, communication standards are not based on such hardware constraints. In addition, an FDD system must perform an additional calculation for obtaining an AGC value due to dispersion of AGC gain parameters in an analog/digital domain. Also, FDD systems require a complex interface with respect to a CPU (Central Process Unit) while performing a gain control process.
Meanwhile, since an offset cancellation unit used for a conventional TDD mode is required to detect preamble data, it is unnecessary to perform an additional calculation for extracting dispersed AGC parameters. However, since such an offset cancellation unit creates time delay, the offset cancellation unit loses its real-time characteristic.

Apparatus for cancellation of DC offset in time division duplexing mode direct conversion receiver


The present invention relates to an improved method for purifying a sulfonated aromatic monomer. The method is an economical method capable of providing a highly pure sulfonated aromatic monomer, in which a salt precipitation step and a recrystallization step are simplified while maintaining the reaction conditions used in a conventional method for synthesizing the sulfonated aromatic monomer, and a purification process is carried out using an easily available and stable chemical substance. The sulfonated aromatic monomer obtained by the purification method will be useful for the preparation of a polymer for a polymer electrolyte membrane and will be advantageous to synthesize polymer with high molecular weight.

Fuel cells are generally classified, according to operating temperature and electrolyte, into an alkaline fuel cell (AFC), a phosphoric acid fuel cell (PAFC), a molten carbonate fuel cell (MCFC), a solid oxide fuel cell (SOFC), a polymer electrolyte membrane fuel cell (PEMFC) and a direct methanol fuel cell (DMFC). Among them, the polymer electrolyte membrane fuel cell and the direct methanol fuel cell, which have excellent mobility, are receiving a great deal of attention as power sources.
Generally, a solid polymer fuel cell comprises a gas diffusion electrode layer disposed on both sides of a polymer electrolyte membrane, an anode as a negative electrode (reduction), and a cathode as a positive electrode (oxidation). In this fuel cell, water is produced by a chemical reaction in the polymer electrolyte membrane, and energy produced by this reaction is converted into electrical energy.
However, in the solid polymer electrolyte fuel cell, hydrogen peroxide (H2O2) is produced as a result of side reactions during the reduction of oxygen in the cathode. Hydrogen peroxide or peroxide radicals, produced in the cathode electrode layer, can deteriorate the electrolyte of the cathode electrode layer or the polymer electrolyte membrane adjacent thereto. In addition, if a phenomenon (crossover) occurs in which oxygen molecules pass from the cathode through the polymer electrolyte membrane to the opposite electrode, hydrogen peroxide or peroxide radicals will also be produced in the anode, potentially resulting in deterioration of the electrolyte of the anode electrode layer.
Ion conductive polymer electrolyte membranes developed in view of such problems are mostly perfluorinated polymer electrolyte membranes and are commercially available as Nafion (DuPont, USA), Aciplex-S membrane (Asahi Chemicals), Dow membrane (Dow Chemicals), Flemion membrane (Asahi Glass), etc.
Commercially available perfluorinated polymer electrolyte membranes have chemical resistance, oxidation resistance and excellent ion conductivity, but are costly and pose environmental problems due to the toxicity of intermediate products generated during the production thereof.
In order to overcome such drawbacks of the perfluorinated polymer electrolyte membranes, polymer electrolyte membranes comprising a carboxyl group, a sulfonic acid group or the like introduced into an aromatic ring polymer have been studied. Examples of such perfluorinated polymer electrolyte membranes include sulfonated polyarylether sulfone (Journal of Membrane Science, 1993, 83, 211), sulfonated polyetherether ketone (Japanese Patent Laid-Open Publication No. Hei 6-93114, and U.S. Pat. No. 5,438,082), and sulfonated polyimide (U.S. Pat. No. 6,245,881).
Accordingly, the present invention discloses a sulfonated aromatic monomer for preparing the above-described polymer introduced with a sulfonic acid group.
Generally, the sulfonated aromatic monomer is prepared according to the following reaction scheme 1. Specifically, as shown in reaction scheme 1, a target compound 1 is prepared by allowing an aromatic monomer 3 to react with fuming sulfuric acid to obtain a sulfonated compound 2 and adding a salt (NaCl) thereto.

However, as shown in FIG. 1 showing a conventional process for purifying a sulfonated aromatic monomer, many process steps are used to obtain the target compound with high purity, and thus the conventional process is disadvantageous in terms of yield and cost.
More specifically, the sulfonated aromatic monomer is to provided by a known method (Journal of polymer science: Part A: polymer chemistry, 2003, 41, 2264-2276). In the known method, a salt precipitation step is carried out twice, resulting in a decrease in yield. Also, because a strong base (NaOH) is used in a neutralization process, a change in the pH of the reaction product occurs even when the amount of the base slightly changes, and thus it is not easy to control the pH. In addition, the use of the strong base (NaOH) causes side reactions. Moreover, a recrystallization process is carried out in a 50:50 (v/v) mixture of alcohol and water. Because the desired compound dissolves in water, but does not easily dissolve in alcohol, it does not easily dissolve in the water/alcohol mixture, and thus the mixture can be used as a recrystallization solvent. However, for recrystallization, the water/alcohol mixture should be used in an amount corresponding to about 30-40 times that of the target compound 1. Thus, the loss of the solvent will result, and the salt (NaCl) can be recrystallized due to the use of excessive amount of the solvent.
Accordingly, the present inventors have made extensive efforts to overcome the problems of the conventional process for preparing the sulfonated aromatic monomer, have found a method for synthesizing a highly pure sulfonated aromatic monomer, which comprise a reduced number of salt precipitation steps, a simplified recrystallization process, and a purification process which is carried out using an easily available and stable chemical substance under mild conditions, thereby completing the present invention.

Method for purifying sulfonated aromatic monomer

KOREA RESEARCH INSTITUTE OF CHEMICAL TECHNOLOGY


Method and apparatus for verifying the result of an arithmetic operation. The invention provides a time and cost efficient method of performing error detection on the result of an arithmetic operation; especially for a division operation. It does so through the novel use of a Carry-Save Adder (CSA). A CSA is known in the art to be faster and less costly to implement than the use of a full adder.

One of the functions of most computers systems is to perform arithmetic operations. Occasionally, an error occurs during an arithmetic operation, often due to malfunction of hardware within the computer system. It is beneficial to detect such an error immediately when it occurs. Traditionally, the detection of such arithmetic errors is performed by providing a duplicate piece of hardware to perform a computation which verifies the main calculation. This can be expensive and potentially very slow.
For instance, in order to detect an addition error the obvious implementation shown in FIG. 1 is to provide an extra full adder 100 to produce the same sum as the original calculation. One would then use an exclusive "NOR" 110 for the width of the result in order to produce a value which indicates whether all of the bits in the first result and the second result were identical. Next, all the bits of the resulting indicator are "AND"ed 120 to generate a single bit result which indicates the success of the operation.
The prime objections to this method are the expense of the full adder 100 and the high propagation delay in performing the full add. Typically, a full adder propagates several outputs including a generate, a propagate, and a compliment of the given result. Once this addition is done there is still the need and expense of performing the exclusive "NOR" and the final "AND" on that result in order to get the single bit answer desired.
It is an object of the present invention to provide a fast and novel method of error detection for arithmetic operations. More particularly, it is an object of this invention to provide such an apparatus and method for detecting errors in a division operation.
It is another object of the present invention to provide a method of error detection which does not require the hardware expense of providing a full adder in the computer system.

Method and apparatus for division error detection


A vehicle seat includes a seat back frame, a foam cushion mounted on the frame, and an air bag assembly mounted upon the frame within a hollow provided in the cushion. A trim cover covers the cushion and conceals the air bag assembly, and includes a side panel facing the side of the vehicle and a front panel facing forwardly. The side panel and front panel are joined together at a vertical extending separable seam. The side panel has a lower portion and an upper portion joined together at a horizontal extending separable seam located adjacent to the lower edge of the air bag assembly. Upon inflation of the air bag, the inflating air bag forces the side panel outwardly causing separation of the separable seams and enabling the air bag to inflate both forwardly through the vertical extending separable seam and downwardly through the horizontal extending separable seam.

It is well known in the automotive industry to provide a vehicle seat having an air bag mounted on the outboard side of the seat back to provide side impact restraint of a seated occupant. The air bag may include a thorax portion that inflates forwardly of the occupant torso, and a pelvis portion that inflates more downwardly and forwardly to restrain the occupant pelvis. The air bag is folded up and stored within an air bag housing that is mounted on the seat back. In some cases a plastic door conceals the folded up air bag and then the door opens to permit the deployment of the air bag forwardly and downwardly. However, it is generally considered to be more aesthetically acceptable to hide the air bag assembly within the seat back beneath the traditional seat cover and to provide the seat trim cover with separable seams that can break apart to permit the air bag to deploy forwardly and downwardly.
It would be desirable to provide an improved vehicle seat with side air bag that would assure the prompt and efficient inflation of the air bag from the seat back to optimize restraint of the occupant.


Radio frequency certificates of authenticity (RFCOAs) are presented. In one implementation, a scattering agent is attached to an object to provide a reproducible radio frequency (RF) fingerprint that can be used to authenticate a tag or a seal for the object. In one implementation, the RF fingerprint is measured and digitized, combined with information associated with the object to which the RFCOA is attached, and stored in a radio frequency identification (RFID) system associated with the RFCOA. A scanner receives the fingerprint and the information and authenticates the information by comparing the fingerprint against a new fingerprint obtained from the object.

A certificate of authenticity (COA) is an inexpensive physical object that is more expensive to replicate than the product or circumstance that it certifies as authentic. A COA has a random unique structure that provides both a unique ID and an avenue for authenticating the unique ID. Additional desirable characteristics of a COA are that the uniqueness of the COA's random structure can be verified using an inexpensive device and/or at some distance from the COA.
From an economic standpoint, a COA is a digitally signed physical object that has a random unique structure for which the cost of creating and signing original COAs is small, relative to a desired level of security. The cost of manufacturing a COA instance should be several orders of magnitude lower than the cost of exact or near-exact replication of the unique and random physical structure of the instance. The cost of verifying the authenticity of a signed COA is also small, again relative to a desired level of security.
An additional characteristic, mainly impacted by desired level of usability, is that a COA must be robust to ordinary wear and tear. To this end, COA instances can be created in numerous ways. For example, when covering a substrate with an epoxy layer, the epoxy particles form a low-rise but randomized 3-dimensional (3-D) landscape that uniquely reflects light directed from a certain position. Such COAs were used for weapons control during The Cold War. There are also COAs created as a collection of optical fibers randomly positioned in an object using a transparent gluing material which permanently fixes the fibers' positions. Readout of the random structure of such a fiber-based COA can be performed in a number of ways using the fact that if one end of a fiber is illuminated, the other end will also glow. Fiber-based COAs have been proposed for banknote protection—the fibers being fixed by a semi-transparent material such as paper.
Only a few efforts have followed these initial forays into creating certificates of authenticity. For example, creating a class of physical one-way functions via speckle scattering has been tried by focusing on Gabor wavelets to produce short digests of the natural randomness collected from an optical phenomenon.
A fiber-based COA scanner prototype has been created, as well as a system for automatically verifying fiber-based COAs to emphasize the impact of point-subset compression on COAs' forging costs. Finally, COAs in the electromagnetic domain have been proposed by several companies such as TAPEMARK (St. Paul, Minn.) and CROSSID (Israel), all of them aiming to detect an RFID's random structure in the far-field. Such detection is prone to spoofing; in addition, such RFIDs can be relatively easily replicated. Also, because detection takes place in the far-field, both of these systems operate in the expensive 60 GHz frequency sub-band.


A shock absorber for use as a construction element of a toy building set, the shock absorber comprising a rod element provided with a collar at a first end and a mounting at a second end; a sleeve through which the rod element extends; an air-filled cylinder element abutting the sleeve and enclosing the collar; the air-filled cylinder element having a cylindrical inner surface which is so configured that the collar on the rod element is in displaceable abutment on the inner wall of the cylinder element; and a spring surrounding the rod element having one end in abutment on the rod element at the second end, and having an opposite end in abutment on the sleeve, whereby the spring presses the sleeve towards the air-filled cylinder element.

The present invention relates to toy building sets and in particular to a shock absorber for toy building sets, said shock absorber comprising a substantially rod-shaped element having at its one end a collar and a guide comprising a sleeve which displaceably encloses the rod-shaped element; and wherein the rod-shaped element and the guide each has means for mounting on another construction; and wherein a spring is arranged which, with its one end, abuts on the rod-shaped element and, with its other end, abuts on the sleeve in such a manner that it uses its spring force to displace the above-mentioned sleeve towards the collar on the first mounting element.
Such shock absorbers are often used in toy building sets for the construction of mechanical models, such as vehicles and the like, wherein the shock absorber can be arranged on movable elements of some kind of movable construction in such a manner that a springy movement is obtained. When the shock absorber is used, e.g., in the construction of a vehicle, the shock absorber can serve as a shock absorber for the movable wheel suspension of the vehicle whereby the model thus built will act approximately as a real vehicle.
U.S. Pat. No. 5,056,764 teaches, e.g., a shock absorber arranged in such a manner that it can easily be mounted on another construction in that the guide for the rod-shaped element in combination with the collar on the rod-shaped element make it easy to mount the shock absorber on another construction by shifting a slotted portion of the other construction in between the guide and the collar on the shock absorber.
However, it is a problem with this solution that, although adequate spring function can be obtained, only a limited shock absorption is obtained, since the absorbing effect is generated as a result of the friction between the rod-shaped element and the guide, and this friction has to be limited in such a manner that it is ensured that the shock absorber does not by itself, during use, become unstuck from the other construction on which it is mounted.
U.S. Pat. No. 4,869,704 teaches another configuration of a spring device for a toy building set whereby a substantially increased absorption effect is obtained in addition to the spring function in that a conical helical by itself triggers the springy as well as the shock absorbing effect, the individual coils of the conical helical spring being in frictional abutment on each other.
The shock absorbing and springy conical helical spring according to U.S. Pat. Nos. 5,056,764 and 4,869,704, respectively, are arranged in such a manner that the shock absorption and the spring effect are obtained simultaneously.
Moreover, e.g., U.S. Pat. Nos. 3,603,575 and 4,869,704 feature a plurality of embodiments of shock absorbers and shock absorbing elements, the construction of which being unsuitably for use in toys since they are, firstly, configured with a view to use of a hydraulic fluid to obtain the internal shock absorbing friction, and, secondly, their construction is relatively complex.
In light of this, it is the object of the present invention to provide a shock absorber for a toy building set of the type described in the introductory part whereby it is possible, on the one hand, by simple means to obtain a substantially increased shock absorbing effect.
According to the present invention, this is obtained with a shock absorber of the kind described in the introductory part in that the guide further comprises a substantially air-filled cylinder element with a substantially cylindrical inner wall which is so configured that the collar on the rod-shaped element is arranged in displaceable abutment on the inside of the cylinder element.
In an advantageous embodiment of the invention, the collar is configured as a piston, and the piston in elastic abutment on the inner wall of the air-filled cylinder element. Hereby a friction between the piston and the air-filled cylinder element is obtained which yields an adequate absorbing effect.
According to a further preferred embodiment, the means for mounting the rod-shaped part and the guide on another construction comprise respective eyes arranged on each of these whereby it is possible to mount in each of said eyes a shaft end or the like part on another construction.
The cylindrical inner wall on the air-filled cylinder element is particularly advantageously closed at its one end and open at its opposite end. Viz, hereby a shock absorbing effect is obtained when the collar is forcibly shifted in the air-filled cylinder element.
Particularly advantageously, the air-filled cylinder element has, at its open end, means for releasable coupling of the air-filled cylinder element and the sleeve. Viz, it is hereby obtained that the cylinder element and the sleeve with the displaceable rod-shaped element can readily be removed from each other.
According to an alternative preferred embodiment, the air-filled cylinder element and the sleeve are provided with means for snaplocking the sleeve to the air-filled cylinder element which means that the two elements cannot be pulled apart during normal use.
Further advantageously, that end of the rod-shaped element opposite the end where the collar is situated comprises a seat for receiving the one end of the spring, and where the other end of the spring abuts on a second seat arranged on the sleeve. Hereby the sleeve with the displaceable rod-shaped element and the spring can be removed from the cylinder element as an integral unit without the spring being dismounted.
In this context, the spring is particularly advantageously a helical spring which is so arranged as to substantially enclose the rod-shaped element.
The above-described separation of the shock absorber is further facilitated by a particularly advantageous embodiment of the invention wherein the means for releasably mounting the air-filled cylinder element on the sleeve is constituted by an abutment surface located at the open end on the air-filled cylinder element and a complementarily configured abutment surface located on said sleeve, and positioning means configured with a view to preventing sideways displacement of the air-filled cylinder element relative to the sleeve. Viz, it is hereby obtained that the cylinder element can be separated from the remaining part of the shock absorber simply by pulling the two elements apart.
Such authentic embodiment of the shock absorber is obtained provided the means for mounting of the rod-shaped element on another construction are arranged on the end of the rod-shaped element which is opposite that end on which the collar is arranged.
In this context, the sleeve is particularly advantageously provided with a through-going opening through which the rod-shaped element can be shifted; and in that the opening has an internal cross sectional dimension that exceeds the cross sectional dimension of the rod-shaped element, measured in the same direction, whereby the rod-shaped element can be shifted substantially without friction in the through-going opening in the sleeve.
Further advantageously, the means for releasable mounting of the guide on another construction are arranged on the cylinder element; and in that the cylinder element has a cylindrical inner wall which is air-tightly closed at the one end, and at the opposite end has an abutment surface for abutment on a corresponding abutment surface configured on the sleeve, whereby the cylinder element and the guide together from a cylindrical space in which the collar can be shifted, and wherein that end of the cylindrical space where the guide is arranged features ventilation passages with a view to ensuring a substantially unimpeded flow of air from the cylindrical space.
According to a preferred embodiment, the piston is configured as a disc in a rubber-elastic material, and said disc has a centrally arranged through-going opening, and the rod-shaped element has an annular recess at its one end, and wherein the disc is mounted on the rod-shaped element in that the annular recess extends through the central opening in the disc. Hereby it is obtained that it is extremely simple to mount that part of the shock absorber that comprises the rod-shaped element, the spring and the sleeve.
A particularly advantageous embodiment is obtained when the annular recess has a given width and when the disc has a thickness which is smaller than the width of the annular recess, whereby the disc is allowed to be displaced in the annular recess longitudinally of the rod-shaped element; and wherein the annular recess is delimited by a first abutment surface that restricts the displacement of the disc in a direction towards the one end of the rod-shaped element, and a second abutment surface that restricts the displacement of the disc in the opposite direction, and wherein each of the two abutment surfaces is provided with a groove that extends from the bottom of the annular recess and to the periphery of the recess on the rod-shaped element. This enables the groove to serve as a throttle passage for the air to be forced past the piston by displacement of the piston in the air-filled cylinder element, and it is hereby ensured by simple measures that an even shock absorbing effect is accomplished, also after a protracted period of use.
If the groove in the first abutment surface has a cross sectional area which is different from the corresponding cross sectional area on the second abutment surface, it is further accomplished that a different throttle area is provided which means that the absorbing effect is different, depending on whether the piston is withdrawn from or inserted into the air-filled cylinder element.
The groove in the first abutment surface can thus advantageously have a cross sectional area which is smaller than the corresponding cross sectional area on the second abutment surface, which means that the absorption peaks when the rod-shaped element with the piston is withdrawn from the air-filled cylinder element whereby the absorption completely or partially equalises the spring force so as to obtain that when a given force is exerted, substantially the same resistance to displacement of the piston in the air-filled cylinder element is accomplished.

Shock absorber for a toy building element


A system for providing voltage isolation includes the first and second chips, each containing functional circuitry. The chips are interconnected via at least one RF isolation link that provides voltage isolation between the first chip and the second chip and limits common mode signals therebetween.

Within power conversion products, there is a need for high speed digital links that provide high isolation at a low cost. Typical digital links within power conversion products require a speed of 50-100 megabits per second. Isolation between the input and output of power conversion products is required in the range of 2,500-5,000 volts. Existing solutions for providing a high speed digital isolation link have focused on the use of magnetic pulse couplers, magnetic resistive couplers, capacitive couplers and optical couplers.
Referring now to FIG. 1, there is illustrated the general block diagram of a system using a magnetic pulse coupler to isolate a digital link 102 between a driver 104 and a detector 106. The driver 104 resides upon one side of the digital link 102 and transmits information over the digital link 102 to the detector 106 residing on the other side of the digital link. Resting between the driver 104 and detector 106 is a pulse transformer 108. The pulse transformer 108 provides a electromagnetically coupled transformer between the driver 104 and detector 106. The pulse transformer 108 generates a pulse output in response to a provided input from the driver as illustrated in FIG. 2. The input from the driver 104 consists of the two pulses 202 and 204. Each pulse 202, 204 consists of a rising edge 206 and a falling edge 208. In response to a rising edge 206, the output of the pulse transformer 108 generates a positive pulse 210. The falling edge 208 of a pulse generates a negative pulse 212. The pulse transformer circuit illustrated with respect to FIGS. 1 and 2 suffers from a number of deficiencies. These include start-up where the detector 106 will not know at what point the input from the driver has begun, whether high or low until a first edge is detected. Additionally, should any error occur in the pulse output of the pulse transformer 108, the detector 106 would have a difficult time determining when to return to a proper state since there may be a long period of time between pulses.
Referring now to FIG. 2, there is illustrated an alternative prior art solution making use of a magneto resistive coupler. The magneto resistive coupler 302 consists of a resistor 304 and associated transformer 306. The resistor 304 has a resistance value that changes responsive to the magnetic flux about the resistor. The transformer detector 306 utilizes a wheatstone bridge to detect the magnetic flux of the resistor and determined transmitted data.
Another method of isolation between a driver 404 and a detector 406 is illustrated in FIG. 4. The driver 404 and the detector 406 are isolated on opposite sides of a digital link 402 by a capacitor 408. The capacitor 408 capacitive couples the driver 404 and detector 406 together to achieve a level of isolation. A problem with the use of capacitive coupling to isolate digital links is that capacitive coupling provides no common mode rejection.
An additional problem with some isolator designs involves the reception of RF interference from nearby transmitting GSM, DCS and CDMA cellular telephones. The problem is caused by the application printed circuit board acting as a dipole antennae at GHz frequencies. This results in large common mode signals being seen at the isolator at RF frequencies. Some manner for minimizing these large common mode signals at GHz frequencies would be highly desirable.
Thus, an improved method for providing isolation over high speed digital links within power supply components would be greatly desirable.

RF isolator with differential input/output


A method of rebuilding a managed information tree includes steps of retrieving a unique key (304); testing to determine if a parent of the unique key exists (308); and if the parent exists, creating a node (318).

Managing a communications network, such as a cable telephony network, requires information about the network. For example, the configuration information about the devices that are part of the network is needed.
The management information required for the management of the network is maintained in a persistent database. During operation of the network, a copy of the persistent database is made and stored for quick access.
Network elements require specific information about their operation. This information is stored in a database in the network element. The information is stored and retrieved by using a managed information tree. A managed information tree (MIT) provides rapid access to the data. The MIT is created and modified as information is stored in the database.
The MIT can be lost. The current method of rebuilding the MIT is to build the tree top down.
This method is time consuming because of the number of cycles required to rebuild the tree.
Thus, a quicker method of rebuilding the MIT is needed.

Method of reconstructing a managed information tree


A fastening device for fixing an electronic device includes a base board; a hook fixed on the base board and capable of inserting into the electronic device; a locking member attached on the base board, the locking member is rotatable in a first rotating plane; an actuating member attached on the base board and adjacent to the locking member, and a resilient member comprising two ends and a winding connecting with the two ends. The actuating member is rotatable between a first position and a second position in a second rotating plane, which is perpendicular to the first rotating plane. The actuating member contacting with the locking member. One of the two ends fixed on the actuating member, and the other one of the two ends fixed on the baseboard. The winding unrestrained disposed by the two ends.

This application is related to copending U.S. patent applications Ser. No. 12/512,998 filed Jul. 31, 2009 entitled "PORTABLE APPARATUS AND FASTENING DEVICE THEREOF" and Ser. No. 12/512,996 filed Jul. 31, 2009 entitled "PORTABLE APPARATUS AND FASTENING DEVICE THEREOF". The disclosures of the above-identified applications are incorporated herein by reference.
1. Technical Field
The present disclosure relates to portable apparatuses, and more particularly to a fastening device for fastening a portable apparatus to an object.
2. Description of Related Art
Portable electronic devices, such as handheld flat screen televisions and portable disc players, are widely used because of small sizes. Users may carry their portable electronic devices when travelling for business or entertainment. However, the users may have to hold the portable electronic devices in their hands or on their thighs or on a flat surface of the vehicle they are travelling in. After a period of time, the users' hands or thighs may become tired or the electronic devices may fall off the table due to the vehicle turning or bumps in the road.
Therefore, a need exits for providing a fastening device that the electronic device can be secured thereof.

This patent is subject to a terminal disclaimer.

Portable apparatus and fastening device thereof

Hong Fu Jin Precision Industry (ShenZhen) Co., Ltd.


A recess portion with a substantially circular cross-section is provided in the upper end surface of a supporting jig. When a probe of a device for friction stir welding is buried in the upper end surface of a layered portion, material in the vicinity of the buried portion flows plastically. This causes the plastically flowed material to flow into the recess portion, and as a result, the material is stirred in a relatively large region. When the material that flowed into the recess portion is cooled and solidified, a friction stir-welded portion-possessing member having a projection portion is obtained.

Spot welding is generally relied upon to join a stacked assembly of members. In recent years, there has been proposed to join such a stacked assembly by friction stir welding (see, for example, Patent Documents 1 through 3).
FIG. 28 shows a stacked assembly 6 comprising a first workpiece W1 and a second workpiece W2, which are stacked together, and placed on a support jig 3, and a friction stir welding tool 7 having a probe 8 embedded in the stacked assembly 6, in the same manner as with an apparatus shown in FIG. 1 of Patent Document 1. The reference characters A3, M in FIG. 28 designate a stirred region which is stirred by the probe 8 and a boundary line between the first workpiece W1 and the second workpiece W2, respectively.
When the stacked assembly is friction-stir-welded, even if the probe 8 is embedded and the material flows plastically, the material cannot project from the lower end face of the first workpiece W1. Therefore, the material of the second workpiece W2 flows plastically to a position near a peripheral side wall of a rotor 9 of the friction stir welding tool 7, and rises to form an annular burr BL. Therefore, a finishing process is required to cut the burr BL away.
As shown in FIG. 29, since the thickness T3 of a region that is compressed by the embedded probe 8 and the thickness T4 of a region of the workpiece W2 directly above a raised portion of the lower workpiece W1 near the embedded probe 8 are reduced, the bonding strength of the stacked assembly 6 is not sufficient.
Furthermore, because the probe 8 is removed after it has been embedded to plastically flow the material in the friction stir welding process, a hole is left in the region from which the probe 8 is removed, tending to reduce the bonding strength of the stacked assembly 6.
To avoid the difficulty that the hole is left in the region from which the probe 8 is removed, Patent Document 2 discloses a technology for holding jigs in abutment against opposite end faces of a stacked assembly, and providing friction stir welding jigs on the sides of the opposite end faces. Specifically, a probe inserted in a through hole in the jig on one side of the end faces is embedded in the stacked assembly to perform a friction stir welding process. Thereafter, the material which flows into a through hole in the jig on the other side of the end faces when the probe is embedded, is pushed back by a probe provided on the other side of the end faces. The projecting material is thus pushed back until the bottom of the hole produced by the removed probe becomes flat, thereby producing flat surfaces.
According to a technology disclosed in Patent Document 3, a stacked assembly is placed on a flat surface of a jig, and an additional material piece is supplied to a region around a probe that is rotated and embedded in the stacked assembly. The additional material piece is welded together with the stacked assembly, filling the hole produced by the removed probe.
The technology disclosed in Patent Document 2 is disadvantageous in that since the two friction stir welding tools need to be installed in opposite directions, the friction stir welding apparatus is complex in structure and the facility investment is expensive.
The technology disclosed in Patent Document 3 results in an increase in the material cost and hence the friction stir welding cost on account of the need for the additional material piece. In addition, because there is a need for a mechanism for supplying the additional material piece, the friction stir welding apparatus is also complex in structure and the facility investment is also expensive.
As shown in FIG. 30, it may be proposed to insert a placement jig 2 having a recess 1 into an insertion cavity 4 in a support jig 3, thereby providing a friction stir welding jig 5. When a stacked assembly 6 comprising a first workpiece W1 and a second workpiece W2 is placed over the recess 1 in the placement jig 2, and a probe 8 of a friction stir welding tool 7 is embedded in the stacked assembly 6, the material of a region A4 is softened to flow plastically, and the material finally flows into the recess 1. Since the material displaced by the embedded probe 8 flows into the recess 1, a burr BL is prevented from being produced. Because the plastically flowing material projects from the lower end face of the stacked assembly, the thickness of the joined stacked assembly 6 is not reduced, and the desired bonding strength is achieved.
Patent Document 1: Japanese Laid-Open Patent Publication No. 2002-178168
Patent Document 2: Japanese Laid-Open Patent Publication No. 2001-259863
Patent Document 3: Japanese Laid-Open Patent Publication No. 2003-62678

Method for friction stir welding, jig therefor, member with friction stir-welded portion, and tool for friction stir welding


An apparatus for controlling the fluid flow rate from a drainage pond that is common in developed sites where the drainage pond is adapted to supply a degree of fluid capacitance so the runoff does not overflow downstream creek beds and the like. The method and apparatus for controlling the fluid draining from a pond comprises a system for allowing a higher flow that is allowed by regulatory bodies when the pond is at a lower level so the pond drains more quickly when it is at a lower water level. Thus the apparatus allows for a smaller retention pond.

The disclosure relates to a hydrostatic pressure flow control device particularly adapted for an above ground or below ground holding pond (generally referred to as a pond) that is adapted to collect storm water where the flow control device is in fluid communication therewith. The general purpose of the pond is to prevent a large influx of water into a nearby stream or the like which can potentially cause environmental damage. Many regulations require storm water and other runoff water to be directed into a holding pond and then discharged at an adequate flow rate to meet regulated criteria.
In an urban development where forest is removed and is replaced with items such as concrete and the like which have distinctly different runoff characteristics, a detention pond must be implemented for handling storm water. In general, there are two things which must occur with storm water: it must be cleaned, and it must be metered. In one preferred form, there is bioswale that is positioned between a control structure and a main pond volume. In low flows, the bioswale acts as a filtering device, whereby water passes therethrough due to gravitational flow to the control structure. In high flows, the control tower essentially backs up the flow, thereby filling the bioswale and the main large tank. In the control structure there is generally an orifice in the upper portion that is adapted to have the water pass therethrough in a "design H" situation which is essentially a two-year flood, whereby the maximum amount of allotted throughput of water, by the local environmental standards, passes therethrough. Of course, this does not occur until the water level is quite high, and the entire pond is filled up to the upper portions and the maximum capacity thereof.
Generally, state and Federal Departments of Ecology are concerned with fluid throughput between various creek beds and the like, so ecological systems such as salmon eggs are not washed out during a deluge or any form of rain or flood. Essentially, the detention pond is adapted to mimic the pre-developed condition, whereby the dampening effect by the inherent capacitance of all of the forest and under brush. Development such as rooftops, parking lots and other hard surfaces decrease an area's water capacitance. Therefore, the natural flow control is effectively reproduced by the pond and a flow metering device.
It should be noted that there are three essential flow durations (rates over a set period of time) that are allowed: 50% of the two-year flood, 100% of the ten-year flood, and 100% of the hundred-year flood throughputs. These amounts are flow durations, which are measured in cubic feet per second multiplied by number of hours.
Therefore, it is advantageous to have a maximum allowable throughput during the various height conditions of the pond. In one form, this is accomplished by having a fixed hydrostatic head with a known orifice where the head will stay constant regardless of the water level as shown in the detailed description below. In one form, this head is 49% of a two-year amount, which is the maximum allotted throughput amount as per the Department of Ecology standards (at the present time of filing in the Inventor's state of residence which is Washington State).
Therefore, it is extremely advantageous to have a controlled higher throughput of fluid so that the backup of water in the settling pond is a lesser net volume. This allows for a greater amount of real estate to be utilized for other, more usable land or preserved land in the pre-developed state.
The apparatus as described further below functions as an early release mechanism. In the northwest region of the United States, a thirteen-acre developed site would normally require a 41,400 square foot sized pond with prior-art flow control systems in place. With the invention as described below in place, the pond is essentially reduced in topographical square feet by 38%. It should be noted that given the angle of repose of the soil, there is a fixed amount of depth and volume that can occur given a certain square-footage of allotted space for a pond. Additionally, in some embodiments the items are submerged in a concrete box beneath usable soil; however, this is an expensive installation, and of course, reducing the overall size is potentially advantageous.
With regard to the above example that was in use, the implementation of the invention would save approximately $75,000 in estimated costs using the flow control system as claimed.
In the Civil Engineering pond design and installation disciplines, there is psychological trend to guard against the maximum flow and not be concerned with the flow rates that occur immediately leading up thereto. In other words, the prior art is concerned with the maximum flow rates where the damage can occur and not exceeding these flow rates; however, this line of thinking has a tendency to neglect the flow rates immediately preceding and leading up the maximum allowable flow rate. A system as described below provides a maximum allowable flow rate as soon as possible to increase the net volume passing through the pond and the system hence allowing a smaller volume pond to be in place.


A method for accomplishing the application to a wearer of a disposable absorbent article having particular features is disclosed. The method includes the step of providing a kit, the kit including a disposable absorbent article having an elastically stretchable topsheet with a longitudinal opening therethrough and a primary serviceable indicium disposed thereon, and a package having secondary information including a depiction of at least part of the absorbent article and the primary serviceable indicium, the primary serviceable indicium and the secondary information being present to aid the care giver in the correct application of the article to a wearer.

Many disposable articles such as diapers and adult incontinence products comprise elasticated, stretchable components, which provide stretch in the longitudinal direction, such as leg cuffs and barrier cuffs. Another example is a diaper with a topsheet with a large opening that can receive feces and pass it to avoid space underneath the topsheet.
The inventors have found that in particular when the elasticated components are such that they can contract the article significantly, application of such absorbent articles can be difficult. They also found that when the elastic forces of such components are very strong, it may be difficult to fully stretch the article while at the same time trying to position it, and/or that a stretched article often folds up or contracts into a less stretched state. They also found that the article is often stretched incorrectly or incompletely or that the elastic components, or the whole article, are applied incorrectly. This may lead in use to leakage and discomfort.
Co-pending application EP1279357 proposes the use of an application aid that helps to fix the article in place during application and thus facilitates the application by the caregiver. However, such an aid may add complexity for the caregiver, and it does still not guarantee correct application of the article and avoidance of leakage or discomfort.
The inventors have now found that when the package of such highly stretchable articles comprise an indication how to stretch the stretchable article and/or how to align the article, e.g. with the genitals and anus of the user, and that when the absorbent articles also comprise a serviceable indicium conveying this information, and that when this serviceable indicium is also included in the secondary information comprised by the package, that then the wearer or care giver will apply the article correctly and the article will be comfortable to wear and it will perform optimally. Because the information of the package also shows the disposable absorbent article and the serviceable indicium thereof, the wearer or caregiver can re-apply the instructions of the package and apply the article correctly, i.e. stretch the article correctly and/or align the article correctly with for example the genitals and/or anus.

Method for application of disposable absorbent articles and providing a kit of a package and disposable absorbent article


A batchwise process for aftertreatment of polyol esters prepared by reacting polyols of the general formula (II)H—(—O—[—CR1R2—]m—)o—OH  (II)in which R1 and R2 are each independently hydrogen, an alkyl radical having 1 to 5 carbon atoms, preferably methyl, ethyl or propyl, or a hydroxyalkyl radical having 1 to 5 carbon atoms, preferably the hydroxymethyl radical, m is an integer from 1 to 10, preferably 1 to 8 and especially 1, 2, 3 or 4, o is an integer from 2 to 15, preferably 2 to 8 and especially 2, 3, 4 or 5, with excess linear or branched aliphatic monocarboxylic acids having 3 to 20 carbon atoms and having a lower boiling point than the polyols used. The process is carried out in the presence of a Lewis acid and in the presence of an adsorbent, while removing the water formed, characterized in that the excess monocarboxylic acid is removed by distillation and water is added to the crude ester obtained at a temperature below the boiling point of water at the particular pressure and the crude ester with added water is aftertreated with avoidance of basic compounds, and the sparingly soluble conversion products and the adsorbent present in the esterification reaction are filtered off.

Esters of polyhydric alcohols, also called polyol esters, find a wide range of varying uses in industry, for example as plasticizers or lubricants. The selection of suitable starting materials allows the physical properties, for example boiling point or viscosity, to be controlled, and the chemical properties, such as hydrolysis resistance or stability to oxidative degradation, to be taken into account. Polyol esters can also be tailored to the solution of specific performance problems. Detailed overviews of the use of polyol esters can be found, for example, in Ullmann's
Encyclopedia of Industrial Chemistry, 5th edition, 1985, VCH Verlagsgesellschaft, vol. A1, pages 305-319; 1990, vol. A15, pages 438-440, or in Kirk Othmer, Encyclopedia of Chemical Technology, 3rd edition, John Wiley & Sons, 1978, vol. 1, pages 778-787; 1981, vol. 14, pages 496-498.
The use of polyol esters as lubricants is of great industrial significance, and they are used particularly for those fields of use in which mineral oil-based lubricants only incompletely meet the requirements set. Polyol esters are used especially as turbine engine and instrument oils. Polyol esters for lubricant applications are based frequently on 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,2-hexanediol, 1,6-hexanediol, neopentyl glycol, trimethylolpropane, pentaerythritol, 2,2,4-trimethylpentane-1,3-diol, glycerol or 3(4),8(9)-dihydroxymethyltricyclo[5.2.1.02,6]-decane, also known as TCD alcohol DM, as the alcohol component.
Polyol esters are also used to a considerable degree as plasticizers. Plasticizers find a variety of uses in plastics, coating materials, sealing materials and rubber articles. They interact physically with high-polymeric thermoplastic substances, without reacting chemically, preferably by virtue of their dissolution and swelling capacity. This forms a homogeneous system, the thermoplastic range of which is shifted to lower temperatures compared to the original polymers, one result being that the mechanical properties thereof are optimized, for example deformation capacity, elasticity and strength are increased, and hardness is reduced.
A specific class of polyol esters (they are referred to as G esters for short) contains diols or ether diols as the alcohol component, for example ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propylene glycol or higher propylene glycols. They can be prepared in different ways. In addition to the reaction of alcohol and acid, optionally in the presence of acidic catalysts, further processes are employed in practice to obtain G esters, including the reaction of diol with acid halide, the transesterification of a carboxylic ester with a diol, and the addition of ethylene oxide onto carboxylic acids (ethoxylation). In industrial manufacture, only the direct reaction of diol and carboxylic acid and the ethoxylation of carboxylic acids have become established as production processes, preference usually being given to the esterification of diol and acid. This is because this process can be performed with no particular complexity in conventional chemical apparatus, and it affords chemically homogeneous products. Compared to this, ethoxylation requires extensive and costly technical equipment.
The direct esterification of alcohols with carboxylic acids is one of the basic operations in organic chemistry. In order to increase the reaction rate, the conversion is typically performed in the presence of catalysts. The use of one of the reactants in excess and/or the removal of the water formed in the course of the reaction ensures that the equilibrium is shifted in accordance with the law of mass action to the side of the reaction product, i.e. of the ester, which means that high yields are achieved.
Comprehensive information regarding the preparation of esters of polyhydric alcohols, also including esters of ethylene glycols and fatty acids, and regarding the properties of selected representatives of these compound classes can be found in Goldsmith, Polyhydric Alcohol Esters of Fatty Acids, Chem. Rev. 33, 257 ff. (1943). For example, esters of diethylene glycol, of triethylene glycol and of polyethylene glycols are prepared at temperatures of 130 to 230° C. over reaction times of 2.5 to 8 hours. Suitable catalysts mentioned for the esterification of polyhydric alcohols are inorganic acids, acidic salts, organic sulfonic acids, acetyl chloride, metals or amphoteric metal oxides. The water of reaction is removed with the aid of an entraining agent, for example toluene or xylene, or by introducing inert gases such as carbon dioxide or nitrogen.
The production and the properties of fatty acid esters of the polyethylene glycols are discussed by Johnson (edit.), Fatty Acids in Industry (1989) Chapter 9, Polyoxyethylene Esters of Fatty Acids, and a series of preparative hints are given. Higher diester concentrations are achieved by the increase in the molar ratio of carboxylic acid to glycol. Suitable measures for removing the water of reaction are azeotropic distillation in the presence of a water-immiscible solvent, heating while passing through an inert gas, or performing the reaction under reduced pressure in the presence of a desiccant. When the addition of catalysts is dispensed with, longer reaction times and higher reaction temperatures are required. Both reaction conditions can be made milder by the use of catalysts. In addition to sulfuric acid, organic acids such as p-toluenesulfonic acid and cation exchangers of the polystyrene type are the preferred catalysts. The use of metal powders, such as tin or iron, is also described. According to the teaching from U.S. Pat. No. 2,628,249, color problems in the case of catalysis with sulfuric acid or sulfonic acid can be alleviated when working in the presence of activated carbon.
Further metallic catalysts used to prepare polyol esters are also alkoxides, carboxylates or chelates of titanium, zirconium or tin, for example according to U.S. Pat. No. 5,324,853 A1. Such metal catalysts can be considered as high-temperature catalysts, since they achieve their full activity only at high esterification temperatures, generally above 180° C. They are frequently added not at the start of the esterification reaction, but after the reaction mixture has already been heated up and has reacted partly with elimination of water. In spite of the relatively high reaction temperatures and relatively long reaction times required compared to the conventional sulfuric acid catalysis, crude esters with a comparatively low color number are obtained in the case of catalysis with such metal compounds. Common esterification catalysts are, for example, tetraisopropyl orthotitanate, tetrabutyl orthotitanate, tetrabutyl zirconate or tin(II) 2-ethylhexanoate. Metal traces in the purified polyol esters can impair the use thereof as plasticizers or lubricants since, for example, the electrical conductivity or the stability to atmospheric oxygen is affected. The prior art proposes a number of measures for converting the esterification catalyst to efficiently removable conversion products.
According to the mode of operation described in DE 10 2009 048 775 A1, the esterification of polyols with aliphatic monocarboxylic acids is conducted with a Lewis acid catalyst in the presence of an adsorbent. In the course of the workup of the crude ester, steam treatment is effected, in the course of which Lewis acid catalyst still present is destroyed. By filtration together with the adsorbent, it is possible to remove the catalyst conversion products in a simple manner. The steam treatment is conducted at temperatures generally of 100 to 250° C. and over a period of 0.5 to 5 hours. During the heating period until the attainment of the working temperature, it is necessary to proceed very gently in order to avoid excessive thermal stress on the crude ester. Especially in the case of preparation of polyol esters based on ether diols, for example triethylene glycol or tetraethylene glycol, the conditions of the steam treatment should be set in a controlled manner, in order to prevent unwanted degradation of the ether chain to by-products. Furthermore, the steam treatment for destruction of the Lewis acid catalyst is time-consuming and impairs the product output achieved per unit reactor volume and time.
It is likewise known that it is possible by addition of water and subsequent treatment with alkaline reagents to convert the Lewis acid catalyst to conversion products having good removability. According to the mode of operation disclosed in DE 30 12 203, the crude ester is admixed with 5% to 50% by weight of water, based on the amount of crude ester, and then heated. The heat treatment with water forms well-crystallized conversion products of the Lewis acid catalyst. The water treatment is then followed by the treatment with alkali.
WO 2007/095262 A2 concerns the esterification of 1,3-propanediol which is obtained from renewable raw materials with fatty acids containing 8 to 40 carbon atoms in the molecule, in the presence of metallic catalysts. After the reaction has ended, the catalyst can be removed by treatment with water.
DE 10 2009 060 865 A1 discloses a process for preparing polyol esters which is conducted in the presence of tin compounds. The crude ester obtained is aftertreated by addition of water. After the aqueous phase has been removed, the polyol ester is optionally treated with a sorbent.
DE 40 02 949 A1 discloses a process for workup of a crude esterification mixture which is obtained by continuous esterification in the presence of metallic catalysts. After the unconverted alcohol has been distilled off, the mixture is cooled, activated carbon is added and the residual alcohol is stripped off with steam or nitrogen in the presence of the activated carbon.
According to the procedure from U.S. Pat. No. 5,324,853 A1, the crude esterification mixture is admixed with an aqueous sodium carbonate solution and optionally with activated carbon. This procedure hydrolyzes the metal compounds to insoluble solids, which can be filtered off before the further workup of the crude ester compound.
In the case of workup of a crude ester mixture which is obtained by reaction of polybasic carboxylic acids with monoalcohols in the presence of Lewis acid catalysts, for example of titanium- or tin-containing catalysts too, the prior art recommends a water treatment for catalyst removal. According to U.S. Pat. No. 5,434,294, the crude ester is treated with an aqueous alkaline solution at temperatures between 80 and 150° C. and then filtered through an adsorbent. In the workup method described in DE 1 945 359, the crude ester is first treated with alkali and the free alcohol is removed by a steam distillation. Subsequently, the product is cooled down to a temperature below the boiling point of the water and then admixed with at least 0.5% by weight of water, based on the product to be worked up. By means of this water treatment, precipitates of the catalyst conversion products having good filterability are obtained.
In order to ensure sufficient removal of the Lewis acid catalyst in the form of catalyst conversion products after the esterification reaction has ended, the prior art teaches a steam treatment in the presence of an adsorbent or a treatment with water at temperatures below the boiling point of water at the particular pressure in conjunction with a treatment of basic compounds. Since, however, steam treatment is time-consuming and the conditions have to be controlled, and a treatment with bases, for example with sodium hydroxide or sodium carbonate, additionally introduces salts which have to be removed again in the course of the crude ester workup, there is therefore a need for a process for aftertreatment of polyol esters which is less time-consuming but simultaneously provides the desired polyol ester in adequate quality, such that there is reliable compliance with the required specification values such as residual acid number, water content, hydroxyl number and residual metal content and the polyol esters can have maximum versatility of use.


The present invention relates to an arc fault detection apparatus using a microcomputer, which divides current paths into a low current path and a high current path depending on the intensity of load current using a source voltage that is applied to a lead wire and determines whether an arc fault signal exists, and which presets a circuit breaking time against the generation of an arc, corresponding to the magnitude of a load, and immediately breaks a circuit if a corresponding arc fault signal is detected within the preset circuit breaking time.

1. Field of the Invention
The present invention relates, in general, to an arc fault detection apparatus and, more particularly, to an arc fault detection apparatus using a microcomputer, which divides current paths into a low current path and a high current path depending on the intensity of load current using a source voltage that is applied to a lead wire and determines whether an arc fault signal exists, and which presets a circuit breaking time against the generation of an arc, corresponding to the magnitude of a load, and immediately breaks a circuit if a corresponding arc fault signal is detected within the preset circuit breaking time.
2. Description of the Related Art
As well known to those skilled in the art, arc faults (series, parallel or ground arcs) occur along electric wiring, and are phenomena occurring due to physical or electric defects caused by the aging or breakdown of wires, defective insulation or overcurrent. Such an arc fault is a major factor in causing fires, so that, recently, a circuit breaker for arc fault protection to break a power supply circuit when an arc occurs on an electrical appliance must be mandatorily used in the U.S.A.
As prior arts related to such an arc fault detector, there are Korean Pat. Appln. Nos. 10-2004-59272 and 10-2004-62043.
The prior arts disclose arc fault detection apparatuses, which detect a source voltage applied to a lead wire and determine whether an arc fault has occurred, thus eliminating malfunction caused by a current detection scheme that is the technology previous to the prior arts, which divide current paths into two paths depending on the intensity of load current generated from the lead wire and determine whether an arc fault occurs based on voltage detection, thus preventing malfunction caused by a pseudo arc signal, and which shorten a circuit breaking time according to the magnitude of a load, thus greatly decreasing risk of causing fires.
Therefore, with the development of the prior arts, advanced technology has been provided to easily detect an arc generated at a load current below a rated current, as well as a load current above the rated current, so as to promptly break a circuit, and, in addition, to eliminate a malfunction of misconceiving a pseudo arc signal, generated due to the construction of various (a plurality of) loads, as an actual arc signal and erroneously breaking a circuit.
However, in the prior arts, the core technology is a method of storing a detection signal, which oscillates in and is input from an analog circuit, in a capacitor, comparing the stored signal with a preset reference signal, and outputting comparison results when current paths are divided into a low current path and a high current path according to the magnitude of a load and it is determined whether an arc fault signal exists. Therefore, output time is not uniform because of the discharging time of the capacitor, so that there may occur several malfunctions in such a way that an arc cutoff time (the period ranging from the generation of an arc to the breaking of a circuit) is not exact.

Arc fault detection apparatus using microcomputer


A surgical imaging system includes spaced-apart first and second x-ray sources mounted above a patient support surface. An x-ray detector mounted below the patient support surface generates first x-ray images based upon x-rays from the first x-ray source and second x-ray images based upon x-rays from the second x-ray source. These first and second x-ray images are used to generate a stereofluoroscopic image via a stereo display for a surgeon performing image-guided surgery. The stereofluoroscopic imaging system may be used in conjunction with robotic surgery. A surgical robot operatively controls a surgical tool in an area between the first x-ray source and the x-ray detector, and between the second x-ray source and the x-ray detector. The system may optionally include a first video camera mounted proximate the first x-ray source and a second video camera mounted proximate the second x-ray source. The stereo display selectively displays the first and second video images or the first and second x-ray image, and dissolves between the sources to correlate an outer view with the fluoroscopic view.

Image guided surgery is becoming more common. Systems are utilized to take data gathered from pre-operative scans by MRI, CT scanners, ultrasounds, or the like. The data is used to generate a three-dimensional image to guide a surgeon during an operation. Often this includes some method for tracking an instrument location with respect to the image displayed by the system. Generally, the image is registered relative to locators attached to the patient. Then, the position and orientation of the surgical instruments is registered and tracked relative to the image and the patient so that the location and orientation of the instruments relative to the image is continuously displayed while the surgeon performs the surgery. However, the current image-guided surgery relies on a preoperative scan. Changes to the surgical area during surgery are not reflected in the image by which the surgeon navigates.
Fluorscopy is used in some types of surgery to provide a continuously updated image of the surgical area. However, the two dimensional nature of the fluoroscopy may not provide sufficient information for surgical navigation.


Machining apparatus wherein the cutting tool is controlled to follow a path defined by successive splines, the geometry of a spline being described as a function of a parameter other than arc length along the spline and which is related to time. At a present position along a spline, the change in such parameter corresponding to a change in arc length is explicitly determined by approximation and used to determine an incremented position on the spline. A desired constant tool speed can thereby be maintained. By using only the first or the first two terms of a Taylor series approximation, a change in the parameter can be explicitly approximated as a linear or quadratic predictor. Alternatively, polynomial or rational approximations may be employed.

1. Field of the Invention
The invention relates to a machining apparatus including a control device for controlling a tool by means of which a part is to be machined on the basis of a predetermined geometry, which control device combines a spline interpolation device with path-determining means for determining a path of the tool on the basis of parametrized splines. The invention further relates to a control device suitable for use in such a machining apparatus.
2. Description of the Related Art
Such a machining apparatus is known from the article "Durchgangiges Spline-Konzept", V. Reetz, Energie und Automation 11 (1989), Special "EMO" 1989, pp. 19-20. This article discloses how for machining complicated parts use is made of spline interpolation in order to be able to describe, in contrast with linear and circular interpolation methods, a part geometry with a minimum number of supporting points. Splines, i.e. polynomials of higher degree, of the third order are used to describe path segments, it being ensured that successive path segments adjoin each other as closely as possible, that is to say that it is ensured that the contour or path to be machined is as smooth as possible. Further, the splines, which are parametrized in terms of arc length, are parametrized so that the spatial speed of the tool to be controlled is substantially constant along the contour to be machined. A spline is then characterized by multi-axis end point coordinates of a path segment, the value of the path parameter at the beginning point of a polynomial (the path length) and the coefficients of the third degree axis polynomials. The calculation of a spline polynomial can be started from a part contour determined by means of a CAD program or from a contour obtained by digitization or scanning. Adaptation of the spline to a contour is effected on the basis of approximation methods, such as a Newton approximation method.
With splines determined in the manner described above, a substantially linear relation will exist between the path covered by the tool and the parameter value, which relation is expressed in terms of arc length. However, in the case of arbitrary splines, such as splines directly originating from a CAD program, such a linear relation will generally not exist. That is to say, the arc length variation, which increases monotonically with an increase of the parameter value, will not increase linearly (at a constant rate) when the parameter value increases linearly. As a result, although the average speed of the tool over a path segment is constant, it is true, the instantaneous speed along the spline varies.

Machining apparatus wherein arc length along a tool path is determined in relation to a parameter which is a monotonic function of time


The present invention, generally speaking, takes into account the programming of a particular ROM in order to calibrate and more nearly optimize the timing of the ROMs timing unit. In one embodiment of the invention, a dummy line is less than fully populated with transistors (loads) in accordance with the greatest degree to which a corresponding actual line is populated with transistors. The dummy line may be a word line or a bit line. Furthermore, both a dummy word line and a dummy bit line may be provided. In accordance with a further embodiment of the invention, if the complement of the number of transistors in the least populated line is less than the number of transistors in the most populated line, then the memory map of the ROM may be uniformly inverted, with the output of the ROM also being inverted. Line loading and cycle time are therefore decreased, allowing for higher speed ROM operation.

1. Field of the Invention
The present invention relates to read only memories (ROMs) and to ROM compilers.
2. State of the Art
A ROM is typically realized as transistors arranged in accordance with a Word-Line/Bit-Line organization. A timing unit, based on a ROM clock signal, generates pulses that control sequencing of the read operation. For example, the timing unit generates pulses to disable/enable bit line precharge, word line selection to enable/disable the sense amplifier and, finally, to register the read value. The proper timing of the foregoing signals depends on various factors including the process technology employed, the size and organization of the ROM, etc. Calibration of the duration of these internal pulses is key to optimizing the read cycle time and the power consumption of the ROM.
It is desirable for the realization of the timing unit to remain the same despite variations in the foregoing particulars. To achieve this end, self-timed synchronous ROMs have been developed. A self-timed synchronous ROM is described, for example, in Silburt et al. A 200 MHz 0.8 um BiCMOS Modular Memory Family of DRAM and Multi-port SRAM, IEEE 1992 Custom Integrated Circuits Conference, incorporated herein by reference.
In a self-timed synchronous ROM, critical path timing is physically modeled within the ROM itself. In general, prior timing unit systems mimic the ROM critical path (the discharge bit line) using "dummy paths", namely a dummy word line and a dummy bit line. These dummy paths model the worst case path delay of a read operation for a given ROM configuration. The worst case occurs in the instance of a word line and a bit line having all the transistors programmed. In some ROMs, only a dummy word line is used. Delay due to the discharge of the bit line is modeled using a programmable delay dependant on the number of word lines.
Referring more particularly to FIG. 1, a four-bit by eight-word ROM is shown, with word lines running in the X direction and bit lines running in the Y direction. (The memory may be organized into right and left memory maps, in which case the word lines may extend also toward the right for a right memory map, not shown.) Each intersection of a word line and a bit line defines one bit of information. If a transistor is formed at an intersection, then that bit is programmed with a logic zero value, for example. If no transistor is formed, then that bit is programmed with a logic one value. A dummy word line 101 is provided having loads at each intersection, thereby modeling the delay of a word line having a transistor at each intersection. Bit lines are paired and input to respective output circuitry blocks 103, each block including a multiplexer, a sense amplifier and an output buffer. A control unit 105 receives a clock signal, an X address and a Y address. The Y address is applied to a Y predecoder 107 that controls the multiplexers to select either bit line zero or bit line one. The X address is applied to an X predecoder 109. Output signals from the X predecoder are applied to respective X post decoders 111 in response to which exactly one of the post decoders is enabled to activate a particular word line.
The arrangement and operation of a conventional self-timed memory control circuit may be better understood with reference to FIGS. 2 and 3. The control circuit may be realized using a D flip-flop (Dff), for example. The Dff has its input tied high and is clocked by a clock signal from the memories timing unit. The Q output signal is coupled through dummy circuity that loads the output and through an inverter back to a (Clear) input of the Dff.
The following sequence of operations is performed:
1. In this case, a positive edge on the (Clk) Clock signal starts a read cycle operation. PA1 2. This positive edge activates a positive pulse on the (Q) output signal of the Dff. This activates for example the sense amplifier, enabling the correct Word Line to be selected, opening the output latches, etc. PA1 3. This pulse is then delayed using the dummy circuitry to reset itself (Clear). At this stage the read has been done, but the read cycle time is not completed. PA1 4. The reset mode is activated on the Dff, so the positive pulse on (Q) returns to low, disabling the sense amps and activating the bit line pre-charge for example. But at this stage the cycle time is not completed since a new positive edge on the clock could not start a new read cycle as the Dff still has its reset input activated. PA1 5. The reset is deactivated so a new read operation can start. This is generally counted as the cycle time (Tcyc). It should be noted that the cycle time is not dependant on the clock duty cycle.
The foregoing worst case approach, although it simplifies ROM design, unnecessarily limits ROM performance.

Cycle time optimization for self-timed read only memory compilers


Audio watermarking is the process of embedding watermark information items into an audio signal in an in-audible manner. In a first embodiment, in case the original audio signal has parts of low signal energy, an alternative signal having a level or strength given by the psycho-acoustic model is combined with the original audio signal. The combined signal is watermarked with watermark data to be embedded. In a second embodiment, in case the original audio signal has parts of low signal energy, an alternative signal having a level or strength given by the psycho-acoustic model is watermarked with watermark data to be embedded, and the audio signal is watermarked with the watermark data to be embedded. The watermarked alternative signal is combined with the watermarked audio signal.

Audio watermarking is the process of embedding information items (called watermark) into an audio signal in an inaudible manner.
An original audio signal co can be considered as representing a channel for conveying watermark information m using a key k. In turn, watermarking can be modelled as a form of communication. There exist different ways of how to incorporate the original signal co into the communication model. In a basic model the original signal co is considered as a noise signal. The information about the host signal is not exploited in the modulation step. In advanced models the original audio signal is examined in the watermark encoder before adding a corresponding watermark signal w. This kind of processing is usually referred to as "watermarking with informed embedding" or simply "informed embedding". In such case the watermark signal w is shaped according to a perceptual model and is then applied to the host signal in the modulation step.

Method and apparatus for watermarking successive sections of an audio signal


A fine-adjustment mechanism for making small adjustments to a cutting angle on a miter saw. The mechanism is used in conjunction with an apparatus that includes a base having at least one recess, and a turntable that supports a cutting tool is rotatably mounted to the base. An angular-adjustment lever is pivotally mounted to the turntable. The angular-adjustment lever includes a first insert proximal to the turntable. The first insert is capable of engaging at least one recess. The fine-adjustment mechanism is mounted to the turntable and includes a fine-adjustment lever pivotally mounted on the turntable. The fine-adjustment lever may include a plurality of notches. A second insert having an opening therethrough is supported by the fine-adjustment lever and adapted to engage at least one recess of the base. A threaded rod supported by the fine-adjustment lever extends through the opening in the second insert. A latch holder may be attached to the fine-adjustment lever. The latch holder contains a spring secured by a retainer plate and a latch having a plurality of protrusions capable of mating with the plurality of notches in the fine-adjustment lever.

A miter saw typically has the capacity to crosscut work pieces placed against its horizontal table and vertical fence. This saw can be rotated to make vertical cuts through a work piece at various angles relative to the fence. A vertical cut is known as a "miter cut."
A compound miter saw has the capability to tilt the blade (counterclockwise) to an angle relative to the table, generally from 0° to 45° left of vertical. A cut made with the blade tilted at an angle (and perpendicular to the fence) is known as a "bevel cut." A cut made with the blade set to both an angle relative to the fence (miter angle) and an angle relative to the base (bevel angle) is known as a "compound cut."
A dual bevel compound miter saw has the added capacity to tilt the blade to an angle relative to the table generally from 45° left of vertical to 45° right of vertical. This arrangement allows for more "compound cut" variations.
A slide miter saw has the saw component mounted to a rail system allowing it to slide backward and forward thereby increasing the saw's cutting capacities. The slide mechanisms are typically added to a compound saw.
Miter saws typically include a detent system that allows the table and the attached cutting tool to be preset to specific angles relative to the fixed fence. A detent system provides an accurate means to preset and reset the saw to make the most popular cuts. A miter saw typically provides 10 to 12 preset detent positions or recesses.
The typical miter saw table includes a rotating disc-like work surface that is supported by the tools' base. The table includes a support member for a lock handle in the front and a saw mounting area to the rear, behind the fence. In addition, a spring-loaded retractable detent pin or wedge is mounted in the handle area The base typically has a rounded front shape that is concentric with its table and includes detent holes or slots positioned to accept the above-mentioned pin or wedge. The locking handle moves to create pressure against the rounded front of the base outside of the detent slot or hole locations. The lock handle may be of a rotating screw-type or lever cam-type design. In order to indicate the saw's preset cutting position, the rotating table supports a pointer that relates to an angle scale on the fixed base.
In using a detent system to preset the miter cut angle, the user would first loosen the lock handle, and retract the detent pin or insert. This would be followed by rotating the table, releasing the detent pin or insert into a desired slot or recess, and relocking the handle. Some users rely on the detent system to hold the saws' position for cutting without using the lock handle.
If a user wants to preset the miter saw for an angle cut not provided by the detent system, he would allow the spring-loaded pin or insert to rest against the front surface of the base outside of the detent slots and tighten the locking handle. For these cuts, the user must use the locking handle to hold the saw's position. Due to the interaction between the lever and the detent, however, the prior art arrangements do not allow for a fine adjustment that is near one of the predetermined detent positions.
One example of the prior art is disclosed in U.S. Pat. No. 5,337,641 (Duginske), which discloses a microadjuster mounted to a flip stop assembly on a T-shaped slot in the track of a miter saw. The microadjuster is adjustably secured to the track, such that the rotation of a bolt moves the flipstop assembly either away from or toward a work piece depending on the rotation of the bolt. The flipstop can then be locked into position on the track. As can be easily seen, the use of a microadjuster mounted on the track of a table saw limits the size of the work piece that can be used. Furthermore, a bulky microadjuster located on top of the track of the table saw makes it difficult to use with smaller table saws or miter saws.
Another example of the prior art is disclosed in U.S. Pat. No. 5,215,296 (Adams et al.). Adams et al. discloses an apparatus for mechanical positioning, and adjustments thereof, or cutting tools such as saws. The apparatus has a microadjustable carriage for use with a work piece such that the carriage rotates relative to the base and moves objects attached to it. Once the desired adjustment has been made, the carriage is secured to the base of the cutting tool using a clamp. One drawback of this type of prior art is its inability for use with table saws that have other than rectangular tops. It would be impossible to use this application on cutting tools having a circular base, such as miter saws.
A further example of the prior art, most notably that used with miter saws is a centering device that is disclosed in U.S. Pat. No. 5,425,294 (Ushiwata et al.). In a benchtop miter saw having a bevel function, a centering system can be used for a zero-tilt angle of the position of cut or for the often-used 45-degree angle of cut. The centering system has a detent lever engaging the worktable at preselected positions for changing the angle of cut. They do not, however, provide a mechanism for finely adjusting the angle of cut, such that the angle can be adjusted plus or minus a few degrees of the selected position.
As the prior art examples show, a number of disadvantages remain. First, no prior art provides a fine-adjustment mechanism for use with a cutting tool having a circular base, such as a miter saw. Those disclosing the use of a lever to position a cut fail to provide a mechanism for microadjustments. Furthermore, it is difficult to finely adjust the lever as the lever normally engages a recess in a worktable. As the lever moves within a few degrees of the recess in a worktable, the lever naturally propagates into the recess making it very difficult for microadjustments. Second, the prior art does not provide for an easy method of making a fine adjustment as most fine adjustments are bulky or must be clamped into position. Finally, the prior art microadjustment mechanisms, because of the number of parts needed to create the device, are not economically viable.
Therefore, what is needed is a fine-adjustment mechanism whereby the user can quickly and easily make slight adjustments to the angle of cut. What is further needed is a fine-adjustment mechanism that is smaller, more efficient and more economical. What is further needed is a fine-adjustment mechanism for use with a variety of saws, such as miter saws and table saws, such that the cutting tool can be quickly adjusted for a specific angle of cut.

Fine-adjustment mechanism to preset a miter saw for precision miter cuts


A system of flow-through cells is obtained by assembling a body with a base plate. The body has a first spring element and a first stop, disposed on opposite end sections of the body, at least one second spring element and a corresponding second stop, disposed on opposite faces of the body, and at least one support element and at least one retaining element, which are adapted for the exact positioning of the body in the receiving openings of a support in three directions.

1. Field of the Invention
The invention relates to a body for the formation of an arrangement of flow-through cells.
The invention relates further to a carrier and the arrangement of flow-through cells.
2. Description of the Related Art
An arrangement of flow-through cells of the above-mentioned type is described in international patent application PCT/EP 00/12668 cited hereinbelow.
FIGS. 24-28 show embodiments which are described in international patent application PCT/EP 00/12668.
FIG. 24 is identical to FIG. 1 of patent application PCT/EP 00/12668 and shows a partial view of a first arrangement of flow-through cells in cross-section. This figure shows an inlet 1 and an outlet 2 of an individual flow-through cell, as well as parts of the adjacent flow-through cells.
The flow-through cell arrangement shown in FIG. 24 comprises a base plate 4 and a fitted body 6. The body 6 features a recess 3, which after connection of the body 6 to the base plate 4 forms a space for creating a flow-through cell with the inlet 1 and the outlet 2. The recess 3 may have any basic surface area; for example, it may be rectangular. Corners are preferably rounded. The outlet 2 and the inlet 1 of the adjacent flow-through cells in the cross-sectional direction are likewise shown. The inlet and outlet of a flow-through cell are preferably each arranged at opposite end-points of the base areas of the recess, for example, at the end-points of the diagonal in the case of an essentially rectangular base area.
FIG. 25 is identical to FIG. 2 of patent application PCT/EP 00/12668 and shows in cross-section a partial view of another embodiment of the flow-through cell arrangement according to FIG. 24. In the embodiment according to FIG. 25, a reservoir 5 is formed as a well in the outer wall of the body 6 connected with the base plate 4. This embodiment enables liquid from the flow-through cell to enter the reservoir 5, but not to flow back into the flow-through cell as long as the reservoir 5 is not filled to the upper edge of the rim on the liquid outlet side.
FIG. 26 is identical to FIG. 3 of patent application PCT/EP 00/12668 and shows in cross-section a partial view of a further embodiment of the flow-through cell arrangement according to FIG. 24. In the embodiment according to FIG. 26, the reservoir 5 is closed off at the top. The result of this embodiment is that also no liquid can escape from the reservoir 5 by evaporation.
In all the above-mentioned embodiments, the body 6 may consist of one part or also of several parts which are preferably joined irreversibly into a unit.
FIG. 27 is identical to FIG. 4 of patent application PCT/EP 00/12668 and shows a cross-sectional partial view essentially confined to the base plate for an embodiment featuring an optical film waveguide as the base plate. In the embodiment according to FIG. 27, the base plate is provided as an optical film waveguide with biological, biochemical or synthetic recognition elements immobilized thereon. According to FIG. 27, this film waveguide comprises layers a, b and b′. The reference symbol g is used in FIG. 27 to indicate the limitations of a flow-through cell which is created by connecting the base plate with the body 6. Reference symbol g thus corresponds to the reference symbol 6 in FIGS. 24 to 26.
On the layer b which is transparent at least in part of the visible or near-infrared spectrum, the thin intermediate layer b′ is first applied and then the layer a, whose refractive index is greater than the refractive indices of layers b and b′. Also, layers a and b′ are optically transparent at least in part of the visible or near-infrared spectrum. In the layer b, grating structures c and c′ are formed as relief gratings, which on application of the layers above these gratings are transferred to these layers. On the layer a, an adhesion-promoting layer f is applied which can improve the adhesion of biological, biochemical or synthetic recognition elements to be immobilized. In this embodiment, these recognition elements are immobilized in spatially separated measurement areas d, which in this embodiment are arranged both on and between the grating structures c and c′. In this embodiment according to FIG. 27, the base plate is finally connected with the body g, which corresponds to the body 6 in FIGS. 24 to 26.
FIG. 28 is identical to FIG. 5 of patent application PCT/EP 00/12668 and shows an arrangement of flow-through cells in which column-shaped arrangements of base plates 4 and the connected bodies 6 together form application blocks 7, which are set in corresponding receiving openings of a common carrier 8 (meta-carrier). In this way, an arrangement of a total of 6 columns each of 6 flow-through cells is created. In the embodiment according to FIG. 28 the carrier has the basic dimensions of a standard microtiter plate. Inlet openings 9 to the inlets 1 (not visible in this figure) are positioned in such a way that they are compatible with the pitch of a standard 96-well microtiter plate, i.e., they are positioned at intervals in each case of an integral multiple of 9 mm (for example: interval of inlets within a column: 9 mm; interval of inlets between adjacent columns: 18 mm). With a corresponding translation of the carrier with the application blocks, the reservoirs 5 are compatible with the pitch of a standard 96-well microtiter plate. In the embodiment, according to FIG. 28, the carrier 8 is designed in such a way that it can take up to 6 blocks. However, spaces for application blocks may also remain unoccupied.

Body for flow-through cells and the use thereof


A new class of high-density, vertical Fin-FET devices that exhibit low contact resistance is described. These vertical Fin-FET devices have vertical silicon “fins” (12A) that act as the transistor body. Doped source and drain regions (26A, 28A) are formed at the bottoms and tops, respectively, of the fins (12A). Gates (24A, 24B) are formed along sidewalls of the fins. Current flows vertically through the fins (12A) between the source and drain regions (26A, 28A) when an appropriate bias is applied to the gates (24A, 24B). An integrated process for forming pFET, nFET, multi-fin, single-fin, multi-gate and double-gate vertical Fin-FETs simultaneously is described.

In 1965, Dr. Gordon Moore, then Director of Research and Development for Fairchild Semiconductor, made the observation that the number of transistor devices per integrated circuit had been doubling every couple of years since the creation of the first integrated circuits in the late 1950's and that he expected the trend to continue for the foreseeable future. This observation was dubbed "Moore's Law" by the trade press. Now almost 40 years later, despite numerous dire predictions of fundamental obstacles, unrelenting industry efforts towards every-increasing semiconductor density have effectively affirmed Dr. Moore's prophetic observation, and the trend is still expected to continue unabated for the foreseeable future. The process of reducing semiconductor device size to increase integrated circuit density is generally referred to as "scaling".
Ongoing scaling efforts of semiconductor MOS (Metal-Oxide-Semiconductor) devices not only contribute to higher integrated circuit packing density, but also improve integrated circuit performance. As the scaling process proceeds towards the physical limits of currently available MOS technologies and techniques, new technologies and techniques are developed to further decrease device size and increase device performance. As MOS device size decreases, tremendous challenges arise in a variety of areas, including source/drain contact resistance and current carrying capacity. In these two areas at least, extremely small size tends to work against performance.
One approach that has been employed to improve current carrying capacity of extremely small-geometry FETs is the creation of "double gate" (also referred to as dual-gate herein) transistors. In principle, double-gate transistors act something like two transistors in parallel, thereby improving current flow between source and drain. Two major types of double-gate transistors have been demonstrated: the planar double-gate transistor and the double-gate Fin-FET.
The planar double-gate FET is not unlike a conventional single gate transistor in that it has a horizontal "planar" transistor body with a source and drain at each end and a channel therebetween. Unlike single-gate transistors, however, the planar double-gate FET has a second gate below the transistor body effectively creating a second, parallel channel between the source and drain. However, there is considerable process complexity involved in forming the second, buried gate and in connecting to it, and the planar double-gate transistor is not significantly different from conventional planar transistor structures in terms of its ability to be scaled. Such planar devices are rapidly approaching the physical limits of scaling.
The double-gate Fin-FET employs thin vertical silicon "fins" that act as the transistor body. Horizontally opposed ends of the fin act as source and drain. The gate structure is formed around the fin in an inverted "U" configuration such that the fin has parallel gates formed along both vertical sidewalls thereof. As in the planar double-gate transistor, the double-gate Fin-FET improves current flow between source and drain by effectively creating parallel channels therebetween. Current flows horizontally through the fin between source and drain when the double gate is appropriately biased. Because the transistor body of the Fin-FET is a thin vertical structure, there can be considerable space savings over similar planar devices. Series resistance in Fin-FETs is a significant problem, however.

International Business Machines Corporation