An insulating layer may be fabricated on a microelectronic substrate by spinning a layer of spin-on-glass (SOG) on a microelectronic substrate and curing the SOG layer by irradiating the SOG layer with an electronic beam. Irradiating may take place simultaneously with heating the substrate to a temperature below about 500.degree. C. An underlying and/or overlying capping layer may also be provided. Alternatively, rather than irradiating the SOG layer, an overlying capping layer may be irradiated.

Insulating layers are widely used on microelectronic substrates, such as integrated circuit substrates. As the integration density of integrated circuit substrates continues to increase, the step heights on the microelectronic substrates may continue to increase. For example, as integrated circuit memory devices become more highly integrated, three-dimensional capacitors may be used which may create step heights of 1 .mu.m or more. These larger step heights may make it more desirable to include insulating layers which can planarize these steps. The planarized steps may allow thinner conductive layers and wider ranges of materials to be used for conductive layers.
Insulating layers are used in integrated circuits in at least three applications. An insulator may be used as an interlayer dielectric (ILD) beneath a patterned conductive layer. An insulating layer may be used as an intermetallic dielectric (IMD) between patterned conductive layers. Finally, an insulating layer may be used as a passivation layer on the outer surface of a conductive layer. In all of these applications, it may be desirable to provide an insulating layer having good planarization characteristics.
Borophosphosilicate silicon glass (BPSG) reflow has been proposed to provide planarized insulating layers. In a BPSG reflow, BPSG is formed on a microelectronic substrate and then reflowed at high temperatures of about 850.degree. C. for thirty minutes. Unfortunately, these reflow temperatures may be excessively high for highly integrated circuits.
Planarized dielectric layers have also been provided by etching 03-tetraethyl orthosilicate undoped silicate glass (03-TEOS USG). Unfortunately, the etch-back of 03-TEOS USG may introduce complicated processing steps.
Spin-on-glass (SOG) has also been used to obtain planarized insulating layers which can be fabricated at low temperatures using simplified processing. Silicate (Si(OH)4), siloxane ((RO)nSi(OH)4-n) and silsesquioxane types are widely used for SOG materials. The silicate and siloxane are generally mixed with an alcohol-based solvent such as methanol, ethanol, propanol, butanol, pentanol, hexanol, methyl cellosolve, butyl cellosolve, propylene glycol, diethylene glycol, or carbinol.
An SOG layer is generally formed on a microelectronic substrate by coating the SOG material mixed with one or more of the above-described solvents on a microelectronic substrate, and then rotating the substrate to uniformly distribute the material. The SOG material in the liquid state can fill grooves or trenches in the substrate to thereby planarize the substrate.
The solvent is then generally evaporated by baking. The evaporated solvent and a carbon component generated from the solvent are generally degassed at approximately 100.about.400.degree. C.
The SOG layer is then cured, for example by heating. In particular, the silicate or siloxane material is heated so that silanol (Si--OH) groups in the materials can produce H.sub.2 O and cross-link to form a Si--O--Si network, thereby resulting in a solid SOG layer. The solid layer has properties which are similar to those of a conventional SiO.sub.2 layer.
When the siloxane or the silicate material is heated, water is generally produced. Accordingly, the volume of the SOG layer is generally reduced during the curing process. Also, the siloxane SOG generally includes some alkyl groups at the position of the silanol group, so that the area of cross-linking may be reduced, to thereby cause less volume reduction.
Unfortunately, the curing process may generate stress in the SOG layer and thereby cause cracks therein. Siloxane SOG may have good crack resistance when it is thickly coated. Silicate SOG is generally more rigid and may create cracks during heat treatment, even when thickly coated.
The SOG curing process generally uses a furnace, oven or hotplate. For example, the microelectronic substrate is heat-treated at a temperature below 350.degree. C. on a hotplate, and is then heat-treated at a temperature below 500.degree. C. for 30-60 minutes in a furnace.
SOG layers may also be hygroscopic during subsequent processing or merely due to the lapse of time. When moisture is absorbed due to the hygroscopicity, the cross-linking may be destroyed and thereby adversely impact the properties of the SOG layer. In particular, as the hygroscopicity increases, the dielectric property of the SOG insulating layer may decrease. Accordingly, it is desirable to reduce or eliminate the problems of cracking and hygroscopicity in SOG layers.
Additional problems may be created when SOG is used for an intermetallic dielectric (IMD) layer between conductive interconnections. In this environment, a "poisoned via" phenomenon may take place wherein the SOG material which is exposed on the sidewall of a via may cause an increase in the contact resistance. In particular, when the poisoned via phenomenon occurs, outgassing may occur in the SOG of the via sidewall which is exposed when a metal layer is deposited, which may cause large contact resistance.
It is known that the poisoned via phenomenon may be caused by the silanol (Si--OH) group in the SOG material. For example, when an aluminum layer is deposited on the Si--OH group, an oxide layer of Al.sub.2 O.sub.3 may be formed, which may thereby increase the contact resistance. Also, when an O.sub.2 plasma treatment for striping photoresist is performed, the amount of Si--OH in the SOG layer may increase and the contact resistance may further deteriorate.
In order to reduce the contact resistance, it is known to seal the SOG exposed on the via sidewall using Ti or TiN. Methods for eliminating the SOG in the via by etchback have also been proposed. Unfortunately, the sealing of the SOG on the via sidewall may use a complicated process. Moreover, it may be difficult to detect an end-point during the etchback process. SOG may therefore remain on the via sidewall, resulting in high contact resistance.
Accordingly, in order to effectively use SOG as an insulating layer for microelectronic devices, it is desirable to reduce or eliminate problems with cracking, hygroscopicity and high contact resistance. It is believed that all of these problems may result from the high temperature curing which is used to eliminate moisture and the silanol group from the SOG. Unfortunately, if the curing temperature is lowered, the moisture and the silanol group may not be completely eliminated and the etch rate of the SOG layer may be increased, thereby causing an increase in the size of the contact holes. Accordingly, it is desirable to increase the curing temperature in SOG while simultaneously preventing cracking. Alternatively, it is desirable to lower the curing temperature while simultaneously eliminating moisture and the silanol group.
It has been previously proposed to use ultraviolet (UV) light irradiation and ion implantation to lower the curing temperature SOG while simultaneously eliminating moisture and the silanol group. In particular, U.S. Pat. No. 4,983,546 to Hyun et al. entitled "Method for Curing Spin-On-Glass Film by Utilizing Ultraviolet Irradiation" discloses a method for curing spin-on-glass by establishing a predetermined initial temperature in a heating chamber with an ultraviolet light source, introducing a wafer into the heated chamber, and gradually increasing the temperature to a predetermined maximum temperature. The SOG film is irradiated with ultraviolet light at a predetermined wavelength simultaneously with the application of heat at the maximum temperature for a predetermined time. The wafer is then cooled.
U.S. Pat. No. 5,192,697 to Leong entitled "SOG Curing by Ion Implantation" discloses implantation of ions such as argon or arsenic into a spin-on-glass layer. The action of the ions moving through the spin-on-glass layer causes internal heating. The heating cures the spin-on-glass layer.
Notwithstanding the above advances, it is desirable to provide improved methods of curing SOG at lower temperatures, to thereby prevent cracks and eliminate moisture and silanol groups from spin-on-glass.

Method of fabricating and curing spin-on-glass layers by electron beam irradiation


Provided are a method, system, and article of manufacture, wherein instructions stored in an option ROM are copied to the system memory of a computer, wherein the option ROM corresponds to a device that is coupled to the computer. A virtual machine is generated, wherein the virtual machine executes the instructions copied to the system memory to boot the device before any operating system is loaded.

A computer may include a system Basic Input Output System (BIOS), also referred to as Read Only Memory (ROM) BIOS or system BIOS. The system BIOS includes programs that are executed for booting the computer when the computer is first powered on. The system BIOS may be stored in an onboard Programmable Read Only Memory (PROM), Erasable Programmable Read Only Memory (EPROM), flash memory, etc., on the motherboard of the computer. The inclusion of the system BIOS in a computer ensures that the even if the computer loses the contents of the main memory when the computer is powered down, the system BIOS can be used for booting the computer. The system BIOS may include code to control hardware components such as the keyboard, floppy drives, certain hard disk controllers, etc.
An option ROM may comprise firmware included on adapter cards that control bootable devices coupled to a computer. In certain architectures, option ROM may also be stored on the motherboard when a bootable device is included in the motherboard. Firmware located on one or more option ROMs may be called by the system BIOS while booting the computer, and the execution of the firmware on the one or more option ROMs may allow the computer to use the bootable devices corresponding to the one or more option ROMs, prior to the loading of the operating system. For example, an adapter card that controls a bootable device may include firmware that may be used to boot the device once the option ROM is loaded and executed by the ROM BIOS.


The invention is directed to a method for operating a level control system of a motor vehicle which includes: a control apparatus, sensors for the direct or indirect determination of the distance of the vehicle chassis to the axles of the vehicle wheels; and, actuators for adjusting the distance of the vehicle chassis to these wheel axles. In the method, the control apparatus checks in a desired-actual comparison based on determined measured values whether the inclination of the vehicle chassis exceeds predetermined limit values. When these limit values are exceeded, one or several of the actuators are actuated in order to obtain a level compensation in the sense of a horizontal alignment of the vehicle chassis. To avoid a turnover of the vehicle (1) in an operating situation on a slope (2), the level compensating control activity is prevented by the control apparatus when the vehicle (1) is disposed in a slope and slant position (angles α, β) which is impermissible for vehicle safety.

Level control systems appear in ever greater degrees of distribution in motor vehicles because these systems make possible a dip compensation of the vehicle chassis relative to the vehicle body, for example, during rapid acceleration operations or for a non-uniform loading state of the vehicle.
These systems include usually a control apparatus which is connected-via sensor lines to sensors for the direct or indirect determination of a distance of the vehicle chassis or vehicle frame relative to the vehicle axles and is connected to actuators via signal lines. With the aid of these actuators, the distance of the vehicle chassis relative to the wheel axis is adjustable in a targeted manner. The sensors are, as a rule, configured as displacement sensors; whereas, the actuators are hydraulically or pneumatically actuable piston-cylinder arrangements or air springs. Furthermore, a hydraulic or pneumatic pump belongs to such a system as do electric switching valves as well as a pressure medium store as may be required. A level control system of this kind is disclosed, for example, in United States patent publication 2002/0079626.
A so-called vehicle slant state is present for an alignment of the vehicle chassis to the particular vehicle axle with this alignment being transverse to the vehicle longitudinal axis. One such operating situation can, for example, be given in that the wheels of the right vehicle side stand on a curb stone while the opposite-lying wheels lie somewhat deeper on the roadway. U.S. Pat. No. 6,234,493 and European patent publication 0,752,329 describe the operation of level control systems in a situation wherein the vehicle slant state is, for example, only controlled out in the sense of a chassis alignment as horizontal as possible when the vehicle, after a vehicle loading operation, is driven down from the curbstone or when previously determined slant state limit values are exceeded.
Furthermore, German patent publication 100 22 834 discloses a method for preventing the turnover of an air-spring suspended vehicle on an inclined roadway. The operating situation described there is comparable to the above-mentioned curb stone situation. Accordingly, this publication relates to a vehicle having a level control system which is effective in a special manner when a vehicle having a high-lying center of gravity (that is, for example, a high-built commercial vehicle such as a bus) stands or travels with its longitudinal axis transverse to a slope.
In the method described in German patent publication 100 22 834, a turnover of the vehicle for a possible shift of weight within the tourist bus because of traveling guests is prevented in that all air springs of the vehicle are vented after the occurrence of specific control preconditions. According to this publication, in such a dangerous situation, however, it can also occur that only the higher-lying air springs on one side are vented and/or the lower-lying air springs on the other side are filled.
Finally, German patent publication 4,003,766 discloses a level control system for an air spring suspended vehicle wherein the level control operation is prevented in a selectable time span in such operating situations when the speed, with which a wheel axle of the vehicle moves relative to the vehicle frame, exceeds a pregiven threshold value. With this method, all those dynamic spring deflection operations with respect to the response of the level control system can be neglected which are generated by normal driving dynamic operations such as speed changes, travel in a curve, driving through potholes, et cetera.
In addition to the described slant state, there is especially in the operation of off-road vehicles an operating situation wherein the vehicle is not directed with its longitudinal axis precisely uphill or downhill, rather, where the longitudinal axis is aligned slanted to the hill. If such an off-road vehicle is equipped with a conventional level control system, the danger is present when exceeding a specific hill slope inclination angle and slant state angle that the vehicle assumes an unstable position with the level compensation unit and turns over.

Method for operating a level control system of a motor vehicle


An apparatus for guiding a seat belt webbing includes a mounting portion and a guiding portion. The mounting portion preferably includes an aperture adapted to receive a vertical post for conventionally mounting a head rest to a vehicle seat back. The guide portion defines an opening for receiving the seat belt webbing. In the preferred embodiment, the opening is defined by a fixed arm and movable arm interconnected by a living hinge.

1. Technical Field
The present invention generally relates to safety restraints for motor vehicles. More particularly, the present invention relates a seat belt webbing guide for positioning an upper portion of a shoulder belt of a motor vehicle.
2. Discussion
Vehicle occupant restraint systems having a seat belt webbing and a guide for guiding the seat belt webbing are well known. In many known vehicle occupant restraint systems, a guide commonly known as a D-ring is attached to a vehicle pillar and vertically adjustable between different positions so that the D-ring and seat belt webbing may be vertically located relative to a particular vehicle occupant. However, a comfortable position of the seat belt webbing may be difficult to attain since the B-pillar may be longitudinally spaced from the vehicle seat. In this regard, the D-ring cannot horizontally travel with the vehicle seat if the seat is adjusted fore and aft. As a result, the seat belt may be difficult to reach (e.g., when the seat is in a foremost position). Additionally, passenger comfort may be compromised as the seat is moved fore and aft.
It is also known to provide a seat belt webbing guide integrally formed with the vehicle seat back. For example, in certain vehicles (e.g., various convertibles), a B-pillar is not present for seat belt webbing or D-ring attachment. Integrally formed webbing guides, while effective, increase production expense and are often considered to negatively effect vehicle styling.


A pair of flags bearing a sports team's colors and/or logo are carried by a pair of upstanding standards that are removably secured to the opposing sides of the visor of a baseball-type cap. The standards are bendable to permit them to assume a desired (e.g. vertical) orientation once attached to the visor. The standards may also be rotatable about their longitudinal axes so that the flags may be oriented as desired by the wearer.

Sports enthusiasts have long sought novel and eye-catching ways to express loyalty to their teams through logo-bearing products such as headwear, pennants, shirts, jackets, and the like. The advent of formal licensing programs by sports teams at all levels of competition, both amateur and professional, along with the increased following of team sports by the general population, have resulted in a proliferation of logo-bearing products associated with sports teams.
Headwear products that are sports team oriented, most notably conventional baseball-type caps, usually display the color or colors of the team, along with a logo and/or team name located on the forward facing portion of the cap where it meets the visor. The display may be embroidered, screen printed, attached by adhesives, or otherwise permanently placed on the cap.
While conventional sports team oriented headwear has tremendous market appeal, there is a need for a fresh and novel approach to headwear displaying team loyalty.


A translucent ceramic contains a main component composed of a tungsten-bronze-type compound represented by a general formula {(Sr, Ba)NbvOw} (wherein v satisfies the relationship 1.8≦v≦2.2 and w represents a positive number for maintaining electrical neutrality), wherein some Nb atoms are replaced with atoms of at least one of Zn and Mg, and the replacement ratio is 0.004 or more in terms of the molar ratio. It is preferable that at least one of Sn and Bi is added in an amount of 0.15 parts by weight or more in terms of SnO2 and Bi2O3, respectively, to 100 parts by weight of the main component, and that the molar ratio of Ba in the (Sr, Ba) site is in the range of 0.25 to 0.50. It is also preferable that the translucent ceramic contains Na in an amount of less than 25 parts by mole relative to 100 parts by mole of the sum of Sr and Ba, or La in an amount of less than 11 moles relative to 100 parts by mole of the sum of Sr and Ba. Accordingly, a translucent ceramic which is inexpensive and which is useful as an electro-optical material and an electro-optical component, such as an optical switch or an optical shutter, including the translucent ceramic can be realized.

When an electric field is applied to a certain type of electro-optical material having ferroelectricity and translucency, the refractive index is changed to generate an electro-optical effect. Therefore, such an electro-optical material has been expected to be used as an optical component such as an optical switch or an optical shutter.
Hitherto, a translucent single crystal of LiTaO3, (Sr, Ba)Nb2O6, or the like has been widely used as such an electro-optical material. However, single crystals are disadvantageous in that the production cost is high, and that it is difficult to obtain materials having a large size.
Accordingly, use of a translucent polycrystalline ceramic has recently, been studied. Such a translucent polycrystalline ceramic (hereinafter, the term "translucent ceramic" used in this description means a translucent polycrystalline ceramic) is obtained by compacting a raw material powder, sintering the resulting compact, and polishing the sintered compact. Therefore, the production cost can be lower than that in a case of a single crystal. (Pb, La) (Ti, Zr)O3 (hereinafter referred to as "PLZT") is known as a typical example of such a translucent ceramic. In this PLZT, some Pb atoms of Pb(Ti, Zr) O3, which is a ferroelectric material, are replaced with La atoms, thereby somewhat decreasing ferroelectricity, and translucency is provided by further performing hot-pressing or the like.
However, PLZT contains lead, and thus the use of PLZT is not preferable from an environmental viewpoint. Furthermore, PLZT is disadvantageous in its optical characteristics become unstable because of volatilization of lead.
Consequently, strontium barium niobate ((Sr, Ba)Nb2O6) translucent ceramics which have a tungsten bronze structure have been actively developed as a lead-free electro-optical material.
For example, Patent Document 1 proposes a method of producing a translucent sintered compact including preparing a mixed solution of aqueous solutions of oxalates of Sr, Ba, and Nb, the mixed solution having a composition ratio represented by a general formula Sr1-xBaxNb2O6 (wherein 0.25≦x≦0.75), allowing ammonia to interact with the mixed aqueous solution to produce a precipitate, thermally decomposing the precipitate, compacting the resulting product, and sintering the resulting compact in an oxygen atmosphere.
Furthermore, Patent Document 2 proposes a method of producing a sintered compact of (Sr, Ba)Nb2O6 including preparing a mixed solution containing Nb, Sr, and Ba, performing a hydrolysis reaction to produce a sol, drying the sol, calcining the dried sol at 800° C. to 1,400° C., mixing the resulting calcined product with a Nb compound, calcining again the mixture at 800° C. to 1,400° C. to prepare a calcined powder, compacting the calcined powder, and sintering the compact at 1,100° C. to 1,400° C.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 62-171957
Patent Document 2: Japanese Unexamined Patent Application Publication No. 63-291844

Translucent ceramic and electro-optical component


A remotely positionable device for use in magnetic resonance imaging includes a magnet which is juxtaposable against the object to be imaged without actually surrounding to object. When so positioned, the magnet generates a static nonhomogeneous magnetic field having a determinable measurement surface wherein both the magnitude and the gradient of the field are substantially constant. Additionally, the device includes an RF antenna for periodically pulsing nuclei in the measurement surface with pulses of the Larmor frequency to initially tilt the nuclei and to subsequently refocus the nuclei. The device also includes a pair of gradient coils which generate a gradient fields that are superposed on the static field to encode the nuclei. The RF antenna subsequently receives a plurality of encoded spin echo signals from the refocussed nuclei which are averaged by a computer to create a measured response. Specifically, the nuclei are refocussed and the encoded spin echo signals are received at a rate that is proportional to the gradient of the static flux field. The computer is also used to create an image from a plurality of measured responses taken from differently encoded spin echo signals.

In the field of nuclear magnet resonance imaging (MRI), it is known that certain atomic nuclei, e.g. .sup.1 H, .sup.19 F, .sup.31 P, have nuclear magnetic moments which, when placed in a static magnetic field, can only take up certain discrete orientations. Each of these orientations corresponds to a different energy state for the nucleus. Further, it is known that the application of radio frequency (RF) radiation to nuclei in a magnetic field can induce a transition in the energy state of nuclei from one level to another. Such a transition is known as nuclear magnetic resonance (NMR) and it occurs under certain identifiable conditions. Many of these conditions relate to the magnetic fields which are imposed on the nuclei.
A magnetic field is described in terms of flux and lines of flux. From the standpoint of an individual nucleus, there are three essential parameters which are characteristic of the magnetic field at the location of a nucleus. These are: 1) the magnitude of the field, 2) the direction of the field as indicated by the flux line through the nucleus, and 3) the gradient, or rate of change in magnitude, of the field at the location of the nucleus. Each of these parameters has its effect on NMR.
As stated above, nuclei assume certain discrete orientations in a magnetic field which may be subsequently changed by RF radiation. The RF radiation which is most effective for inducing such a change is a particular frequency which depends on the magnitude of the magnetic field at the location of the nucleus. This particular frequency, more familiarly known as the Larmor frequency, is equal to the angular frequency of precession of the nucleus spin vector about the direction of the magnetic field vector. When changes in the orientations of nuclei are induced by radiation applied at the Larmor frequency, the magnetic moments of the nuclei will generate signals which are characteristic of the nuclei. These signals are receivable by an RF antenna. Specifically, for medical applications, it is known that nuclei of various tissues will have different NMR responses. Further, it is known that particular parameters of the NMR response can be weighted using known mathematical techniques to more definitively identify the tissue.
As a practical matter, there are always many nuclei in the object to be imaged by NMR, and each nucleus will generate its own signal. However, as long as the nuclei are spinning in phase with each other, their individual magnetic moments are coherent and create a net moment. Insofar as NMR is concerned, it is known that nuclei, under the influence of a field gradient, will begin to defocus or depolarize after their energy states have been changed. Further, it is known that the rate at which the nuclei defocus is essentially proportional to the dominant field gradient. While it is important to recognize that selectable field gradients can be imposed to encode nuclei, these encoding gradients are controllable and are deliberately imposed for the specific purpose of generating a useable encoded NMR projection which can be received by an RF antenna. This condition, however, is to be distinguished from the condition caused by uncontrollable permanent field gradients which are caused by inhomogeneities in the field. It is these permanent, and basically inherent, field gradients which cause nuclei to spin out of phase with each other, i.e. become defocused. When the nuclei become defocused, a condition is created wherein the NMR signal is not detectable. The object then, is to maintain a focused, in-phase, alignment of the nuclei which will give a net moment signal that can be detected.
A solution to this problem is to create a magnetic field wherein there are no permanent field gradients, or wherein the gradients are so small they will cause negligible defocusing effects on the detectable signal. To this end, numerous inventions have created homogeneous magnetic fields having regions where there are effectively no field gradients. The only field gradients in the homogeneous region will then be those which are intentionally imposed to impart an encoding pattern. This, however, is an idealized homogeneous field system which, in practice, is very difficult to achieve. In some systems a high degree of homogeneity is achievable. The expense, however, is great.
Typically, NMR systems which use homogeneous magnetic fields require exceedingly large high-powered magnets. The systems are extremely bulky and cumbersome and are, therefore, effectively immobile. Further, the region of homogeneity is substantially surrounded by the magnet. Stated differently, the homogeneous field is an internal field. Nevertheless, due to the fact that homogeneous fields are capable of generating high quality images, NMR systems which generate homogeneous fields are widely used.
Because NMR is capable of yielding extremely valuable information on the structure of molecules, one very important application for NMR is in procedures for the noninvasive clinical imaging of the human body. As an example, U.S. Pat. No. 4,498,048 which issued to Lee et al. for an invention entitled "NMR Imaging Apparatus" is typical of a commonly used medical MRI system. In addition to its bulk and immobility, a significant aspect of systems such as the Lee et al. system is that it must substantially surround the object to be imaged. A notable exception in this field, however, is U.S. Pat. No. 5,117,188 which issued to Ohkawa for an invention entitled "Quasi-Open Magnet Configuration for use in Magnetic Resonance Imaging". While systems such as Ohkawa avoid surrounding the imaging region, the generation of an exterior homogeneous field requires the juxtaposition of large and strong opposing sources. Again, as with the other systems which generate homogeneous fields, Ohkawa's system is bulky and effectively immobile.
In light of the above, the present invention has recognized that external nonhomogeneous fields can be generated by relatively small magnet configurations and used to advantage for MRI systems. Such MRI systems must, however, accommodate the characteristics of the external nonhomogeneous field. To do this, there are three particularly important considerations. As more fully discussed below, these are: 1) the rate at which nuclei defocus and can be refocussed, 2) the mechanism of signal to noise ratio (SNR) compensation, and 3) the diffusion of nuclei as they defocus. As further recognized by the present invention, the adverse effects of both the second and third considerations can be overcome by proper use of the first consideration.
An exterior nonhomogeneous flux field has an inherent dominant field gradient, denoted (G.sub.z), which acts in a direction, denoted (z), which is substantially perpendicular to surfaces of constant field magnitude, denoted (B.sub.0). Such surfaces, in conjunction with selected Larmor frequencies will establish an image plane which is exterior to the static magnet being used to generate the nonhomogeneous field. As alluded to above, it is the dominant and permanent field gradient G.sub.z in a nonhomogeneous field which defocuses the nuclei and causes the NMR signals from the image plane to deteriorate. The dominant gradient may also require wider system bandwidths, thus allowing more noise power to corrupt the NMR signal. Finally the presence of a large G.sub.z cause incoherent dephasing that is irretrievable.
It is known, however, that controllable and selectable flux gradients G.sub.x and G.sub.y (where x and y are perpendicular to z and transverse to the image plane) can be imposed to encode nuclei. In an exterior nonhomogeneous field, however, the gradient G.sub.z dominates the other gradients G.sub.x and G.sub.y. This dominance by G.sub.z has its implications. For instance, it is known that once nuclei in the field have been aligned by a pulse of RF radiation into an orientation wherein their net magnetic moment signals are in phase, the nuclei will defocus more quickly from the aligned orientation as G.sub.z is increased. However, as G.sub.z is increased, the nuclei will also refocus at the same faster rate back into the aligned orientation if refocussed by RF radiation. The implication of this, which is recognized by the present invention, is that the increased rate of defocus and refocus can be effectively used to shorten the time interval between nuclei refocussing pulses. From the above, it is to be appreciated that with a very large dominant G.sub.z the time for refocus and defocus is very short. For example, for a G.sub.z equal to 400 Gauss/cm the time for nuclei to refocus and defocus in a one millimeter thick slice is less than 10 microseconds. Realistically, the time interval is so short that it is practical to obtain only one independent measurement of the net magnetic moment in the interval between refocussing pulses.
Restated from above, the fact that nuclei defocus very quickly in an external nonhomogeneous field is offset by the fact that defocused nuclei can be refocussed just as quickly. Therefore, although a useable net magnetic moment is short lived, it can be regained quickly. With this capability, it has been recognized that the effective sampling rate, i.e. the rate at which independent measurements of a net magnetic moment can be made, is on the order of the periodic rate at which nuclei can be refocussed.
The second problem with the dominant gradient G.sub.z in the external nonhomogeneous field is related to the fact that a wider system bandwidth is required to accommodate the wider range of Larmor frequencies. This results in a decreased signal to noise ratio (SNR) due to the extra noise power associated with the wider bandwidth. This decrease in SNR may be offset, however, by the fact that an independent measurement of the net magnetic moment NMR response can be accomplished more quickly in the higher bandwidth cases. Accordingly, with standard signal averaging techniques, an accelerated averaging rate afforded by the high gradient G.sub.z, can be used to efficiently compensate for the wider noise bandwidth.
As also indicated above, the third issue of molecular diffusion inherent with nonhomogeneous magnetic fields can be overcome by the rapid refocussing rate which is made possible by a high gradient G.sub.z. Simply stated, molecular diffusion is a phenomenon associated With the random motion of defocusing nuclei in a large field gradient G.sub.z. Although the random displacement of the diffusing nuclei may be small, the different Larmor frequencies experienced in a large field gradient causes the nuclei to defocus randomly. The real difficulty of molecular diffusion is due to the fact that the nuclei will also refocus randomly. Diffusion related dephasing is, therefore, effectively an irretrievable process. That is, of course, unless the process can somehow be controlled. To this end, the present invention has recognized that the high refocussing repetition rate, afforded by a high field gradient G.sub.z, allows nuclei to be refocussed before diffusion proceeds to the point where the previous orientation of nuclei is irretrievable.
Non homogeneous field MRI systems which have heretofore been proposed have neither taught nor suggested ways in which to exploit the unique characteristics of an external nonhomogeneous flux field for the purposes of MRI. For example, both U.S. Pat. No. 5,023,554 which issued to Cho et al. for an invention entitled "Fringe Field MRI", and U.S. Pat. No. 4,379,262 which issued to Young for an invention entitled "Nuclear Magnetic Resonance Systems", disclose the use of a nonhomogeneous magnetic field for MRI and suggest the field may be external to the magnet. In particular, Cho et al. disclose a fringe field having strengths substantially greater than two Tesla. Importantly, neither Cho et al. nor Young, disclose a system or method which uses accelerated refocussing to overcome the above described mechanisms concerning defocusing, the rapid deterioration of SNR or diffusion under the influence of a large dominant gradient G.sub.z. Such a system or method is particularly required to compensate for the weaker signals and more dominant gradients present in lower field strength devices (e.g. <2 Tesla).
The refocussing of nuclei necessitated by field inhomogeneities has been considered before. For example, U.S. Pat. No. 4,656,452 which issued to Bendel for an invention entitled "Method to eliminate the Effects of Magnetic Field Inhomogeneities in NMR Imaging and Apparatus therefor" discloses a method whereby nuclei in a magnetic field, which have been pulsed with RF radiation, are repetitively refocussed after they begin to defocus. Bendel, however, does not teach or suggest using such a method with an external magnetic field where G.sub.z dominates the controllable gradients G.sub.x and G.sub.y. Therefore, and more specifically, Bendel does not address the problems inherent with establishing and identifying a portion of an external magnetic field where effective MRI can be accomplished using an external nonhomogeneous magnetic field. As another example, U.S. Pat. No. 4,542,343 which issued to Brown for an invention entitled "Computer-Controlled, Portable Pulsed NMR Instrument and Method of Use wherein Depolarization is Ultrashortened using Pseudo Randomly Spaced and Oriented RF Depolarization Pulses" discloses a device and method for using NMR responses to determine the fluid-flow properties of a rock sample. Although Brown discloses use of an external magnetic field, and the use of rapid refocussing techniques to overcome the inadequacies of magnetic field inhomogeneities, Brown is not concerned with imaging. Consequently, Brown neither teaches nor discloses how the components and capabilities of such a system can be used for MRI.
In light of the above it is an object of the present invention to provide a diagnostic MRI device which is compact and remotely positionable relative to the object being imaged. It is another object of the present invention to provide an MRI device which does not confine the measurement surface within the structure of the magnet during an MRI procedure. Another object of the present invention is to provide an MRI device which is configured to establish a substantially flat measurement surface in an external nonhomogeneous magnetic field. Still another object of the present invention is to provide an MRI device which improves the effective SNR in an NMR response by accelerated signal averaging using a sampling rate that is on the order of the periodic rate of refocussing. Yet another object of the present invention is to provide a device which effectively uses an external nonhomogeneous static magnetic flux field for MRI. Another object of the present invention is to provide an MRI device which allows for a trade off between a higher SNR and increased speed in image acquisition. Still another object of the present invention is to provide a method for using an MRI device which accomplishes the objects set forth above. Another object of the present invention is to provide a method for generating images using a plurality of NMR responses which are acquired at a rate that is proportional to the field gradient. An object of the present invention is to provide an MRI device and a method for NMR imaging that is easy to use and comparatively cost effective.


An automatic retractable device of a flexible printed circuit board is described. The automatic retractable device of the flexible printed circuit board comprises a bracket, two elastic components and two rollers. By combining the elastic components, the rollers and the flexible printed circuit board, the flexible printed circuit board can revert to an original position after the flexible printed circuit board is used.

Printed circuit boards are basic components of electronic products. Printed circuit boards are classified into two sorts according to their substrates: rigid printed circuit boards and flexible printed circuit boards. The rigid printed circuit board is principally applied in a motherboard or a peripheral card of a computer, a communication product, such as a board of a mobile phone, or a board of a consumer product. The flexible printed circuit board is widely used, and the flexible printed circuit board can be divided into four sorts according to functions: lead line, printed circuit, connector, and integration function system.
The basic portion of a flexible printed circuit board is a film, which is used to support circuits composed of copper pieces. Because the flexible printed circuit board has properties of lightness, soft, thinness, smallness, ductility, flexibility and high wiring density, the flexible printed circuit board can be three-dimensionally wired and the shape of the flexible printed circuit board can be changed according to space limitations. The flexible printed circuit board is therefore typically applied in tiny products, such as notebook (NB), mobile phone, personal digital assistant (PDA) and information appliance (IA). For example, the flexible printed circuit board can be used as a connection between a liquid crystal display (LCD), a floppy disk driver (FDD), a hard disk driver (HDD) or a compact disc read only memory driver (CD-ROM) to a motherboard; a connection between a component, such as slot or far-infrared ray transmission, to a motherboard in a high-end level notebook; tone push-buttons of a mobile phone or a personal digital assistant; and a connection between a microphone or numeral keys and a panel of a liquid crystal display.

Automatic retractable device of flexible printed circuit board


A filtering assembly for separating solids suspended in a solution includes a control device closing a plurality of supply devices for the solution to be filtered and for washing liquid and opening a drain valve of an outlet of the assembly in response to a critical level of accumulation of solids on a pulp detector.

Filtering systems of the type described herebelow are known and, in general, as disclosed in Applicant's copending applications 08/893,698 and 08/272,695 and the U.S. Pat. No. 5,736,039, include a rocking filter body provided with a filtering sleeve which houses a two stage helical turbine generating a filtering effect. Further the filtering system has a counterwashing circuit formed with a plurality of arc shaped piping mounted around the rocking body and connected to a washing liquid supply means which is provided with a plurality of radially extending into the filter body nozzles or nipples and terminating around the filtering sleeve. Finally the filtered exit circuit includes a grid shaped pulp detector housed within a tank receiving the filtered product and formed under the filtered product exit of the rocking filter body.
The described above structure is reliable and well performing unless the filtering sleeve is ruptured. As a result the non-soluble solid material separated from the liquid product by the turbine and intended to be evacuated through a respective exit of the rocking body is accumulated by the grid pulp causing thereby misfunction of a pulp detector which leads, in turn, to an overflow in the tank and eventually to a loss of the processed product.
As a result of the mentioned above drawback the assembly is controlled by a skilled worker who in case of emergency has to disconnect parts of the assembly to clean the tank.
Still another problem stemming from the known structure is reprocessing of an already processed product leading to an inefficient process.


The object of the present invention is to provide an ink jet recording material which has no cracks on the surface of the ink-receiving layer and possesses both the color developability and the absorbability of pigment inks. According to the present invention, there is provided an ink jet recording material formed by coating a coating solution of a pigment layer and a coating solution of at least one ink-receiving layer in succession on at least one side of a paper support and drying the resulting coating layers, wherein the pigment contained in the pigment layer has an average secondary particle diameter of not less than 1 μm and not more than 5 μm, 50% by volume or more of the total volume of the pigment has a secondary particle diameter of not less than 1.2 μm and not more than 15 μm, a first ink-receiving layer directly coated on the pigment layer contains at least inorganic ultrafine particles, a hydrophilic binder and boric acid or a borate, and the dry coating amount of the first ink-receiving layer is not less than 20% by mass and not more than 120% by mass of the dry coating amount of the pigment layer.

Recently, owing to remarkable progress of ink jet printers and plotters, minute images of full color can be easily obtained.
Ink jet recording systems perform recording of images or letters by ejecting ink droplets according to various operational principles and depositing them on recording materials such as paper. The ink jet printers or plotters recently rapidly spread in various uses as apparatuses for making hard copies of image information such as letters and various figures produced by computers. Particularly, color images obtained by multicolor ink jetting systems are not inferior in quality to the recorded images obtained by the multicolor printing according to plate making systems or the color photographic processes. Moreover, when a small number of prints are to be produced, they can produce the prints more cheaply than the printing process or photographic process. Thus, ink jet recording systems are being widely applied to the field of multicolor image recording.
Moreover, with diversification of uses, use of them for preparation of large-sized posters and POP arts and for drafting has increased. In these uses, satisfactory images can be obtained due to utilization of high sharpness and excellent color attainable by ink jet recording, resulting in a high propaganda effect. Application to these uses increases because images excellent in image reproducibility or color reproducibility such as sharpness and colorfulness can be easily obtained on personal computer level, and this is a reason for making much use of ink jet recording materials.
Owing to enhancement of performance and diversification of these ink jet recording apparatuses, needs for ink jet recording increase and, as a result, characteristics and demands required for recording apparatuses and ink jet recording materials are also considerably enhanced. For example, in the case of the uses for large-sized posters or POP arts and the uses for outputting photographic images, these uses are indoor or outdoor displays or personal recording and storage, and, hence, weathering resistance and storage stability of images higher than those of conventional technologies are demanded. For these demands, improvement in inks and ink jet recording materials has been advanced and considerably higher storage stability has been attained. However, light resistance has not yet reached the level of silver salt photography and thus the demands have not yet been satisfied.
In order to satisfy these demands, recently, inks of pigment type are used. It is known that since the pigment inks are less in deterioration by light and do not redissolve in water, weathering resistance and storage stability of the resulting images are higher than those of the images obtained with inks of dye type. However, since the colorant pigment in the inks is insoluble in solvents, being different from dyes, the colorant pigment in the inks must be stably dispersed and the proportion of the colorant pigment in the ink cannot be easily increased. Furthermore, the pigment inks are not so high in coloring efficiency as the dye inks and can hardly give clear colors.
Therefore, naturally the demand for ink jet recording materials also increases. As a method for improving absorbability for pigment ink, it is considered to increase thickness of the ink-receiving layer coated on a support. According to this method, the ink absorbability can be improved, but color developability deteriorates because the ink deeply penetrates in the direction of base paper. As mentioned above, the pigment ink cannot develop clear color as compared with dye ink, and hence in the case of the pigment ink, the color developability is considerably deteriorated when the ink deeply penetrates. Furthermore, the deterioration is further conspicuous in the case of ink jet recording materials having no ink-receiving layer.
For obtaining satisfactory ink jet recording performance, there is proposed an ink jet recording material which contains inorganic ultrafine particles, and there is disclosed an ink jet recording material which uses synthetic silica having a primary particle diameter of 3-30 nm and prepared mainly by a gas phase method (see, for example, Patent Documents 1 and 2). Furthermore, there is disclosed a method of providing a coat containing inorganic ultrafine particles, polyvinyl alcohol and boric acid or a salt thereof on an ink solvent non-absorbent support (see, for example, Patent Documents 3-5). According to this method, the coat can be obtained without causing occurrence of cracking if the dry coating amount of the coat is small, but the coat is low in ink absorbability, and in order to provide a thick coat to improve the ink absorbability, it is necessary that a coating solution is coated after heating the solution to higher than room temperature or the coat is cooled after coating, thereby to set the coating solution on the support to form a firm bond between a viscosity increasing agent and inorganic ultrafine particles or a binder, followed by carrying out drying. Therefore, the production efficiency lowers and besides even if the coat is made thicker, the ink absorbability is sometimes unsatisfactory.
For obtaining an ink jet recording material which aims at attaining both the color developability of pigment ink and the ink absorbability, it is proposed to coat, on an ink solvent non-absorbent support, a first ink-receiving layer containing a gas phase process silica, boric acid or a borate and polyvinyl alcohol and a second ink-receiving layer containing alumina or an alumina hydrate, boric acid or a borate and polyvinyl alcohol in succession (see, for example, Patent Document 6). According to this method, an improvement of ink absorbability can be attained, but it is still insufficient.
For improving the ink absorbability, it may be considered to provide an ink-receiving layer having the above construction on a support having gas permeability and ink solvent absorbability such as a paper support. However, in the case of using an ink solvent non-absorbent support, a binder component or the like in the coat does not fall into the support and, hence, cracking of the coat does not occur while in the case of using a support having ink solvent absorbability such as a paper support, the binder component or the like in the ink-receiving layer falls into the paper support and cracking of the surface of the ink-receiving layer is apt to occur. The cracking of the coating layer becomes conspicuous when an ink-receiving layer comprising a fine particle pigment of several ten nm to several hundred nm in particle diameter is used for the purpose of imparting gloss. There is the problem that when the pigment ink falls into the cracks, color developability lowers to deteriorate the pigment ink characteristics.
In order to enhance color developability and fixability of pigment ink, it is proposed to use an alumina hydrate as a pigment used in the ink-receiving layer (see, for example, Patent Document 7). The color developability and fixability of pigment ink are improved according to this method, but there is a problem that even if a paper support of high absorbability is used, the ink absorbability is insufficient.
On the other hand, there is proposed an ink jet recording material in which a silica porous layer is provided as a lower layer and a layer containing alumina or alumina hydrate is provided as an upper layer or a recording material in which an absorbent layer containing a pigment is provided as a lower layer and a layer containing pseudoboehmite is provided as an upper layer (see, for example, Patent Documents 8 and 9).
When the upper layer containing inorganic ultrafine particles is formed by coating a coating solution of the upper layer on a lower layer comprising porous silica and drying the coat, the inorganic ultrafine particle component or the like in the upper layer falls into the lower layer. As a result, cracking of the surface of the upper layer is apt to occur to cause reduction of surface gloss, and, furthermore, when a dye ink is used in ink jet recording, ink absorbability is improved due to many cracks, but in the case of using a pigment ink lower in color developability than the dye ink, the pigment ink falls into the cracks, which may cause deterioration of pigment ink characteristics.
Furthermore, an ink jet recording material is proposed which comprises an undercoat layer containing a basic material provided for improving color developability of ink and a porous image receiving layer comprising fumed alumina provided on the undercoat layer (see, for example, Patent Document 10).
However, since the undercoat layer containing a basic material comprises only a polymer component such as gelatin, the polymer component is swollen with water contained in the porous image receiving layer during coating of the porous image receiving layer, and strain occurs during drying of the porous image receiving layer, which may cause cracking of the porous image receiving layer and reduction of gloss and deterioration of the pigment ink characteristics.
[Patent Document 1] JP-A-10-203006 (pages 3-9)
[Patent Document 2] JP-A-8-174992 (pages 3-6)
[Patent Document 3] JP-A-7-76161 (pages 2-3)
[Patent Document 4] JP-A-10-193777 (pages 2-10)
[Patent Document 5] JP-A-2002-2094 (pages 2-10)
[Patent Document 6] JP-A-2002-225423 (pages 2-7)
[Patent Document 7] JP-A-2002-79748 (pages 2-4)
[Patent Document 8] JP-A-6-55829 (pages 2-3)
[Patent Document 9] JP-A-7-89216 (pages 2-6)
[Patent Document 10] JP-A-2002-331746 (pages 3-5)


A recording apparatus according to the present invention has a structure such that recording position of each dot is inverted in one pixel area in such a manner that a direction in which dots of lines in the main scanning direction to be formed on a printing sheet is made to be different from the main scanning direction. Even if the printing sheet feeding apparatus encounters displacement and the position of the printing sheet with respect to a thermal head is displaced, the foregoing structure causes dots to be formed in a zigzag configuration for the lines in the main scanning direction of the printing sheet on which a dot pattern has been formed in accordance with image data so that generation of moire fringes in the main scanning direction is prevented. Since the recording apparatus according to the present invention enables a required printing mode to be selected from a plurality of printing modes for the printing processes for printing yellow, magenta and cyan color components, generation of moire fringes in the main scanning direction can be prevented and change in the hue can be restrained without deterioration in the resolution of the recorded dots even if the position of the magenta dot or the cyan dot is displaced with respect to the position of the yellow dot.

The present invention relates to a recording apparatus for recording image data on a printing sheet. More particularly, the present invention relates to a thermal transfer recording apparatus for recording an image on a printing sheet by operating each thermal head in accordance with the depth of image data to be printed while moving the printing sheet with respect to a thermal head having a plurality of heat generating devices.
A thermal transfer recording apparatus is also called as a thermal transfer printer. The thermal transfer recording apparatus is a recording apparatus having a structure such that a thermal head is pressed against an ink ribbon placed on a printing sheet wound around a cylindrical platen and ink is melted or sublimated so as to transfer color pigment to the surface of the printing sheet. The thermal head has a plurality of heat generating devices (heaters) horizontally forming a line, the heat generating devices being arranged to relatively move for a predetermined length while being brought into contact with the printing sheet. Then, the heat generating devices are caused to generate heat for a period corresponding to the depth of each pixel for each line so that one image is printed.
When a color image is formed by a thermal transfer recording apparatus of the above-mentioned type, three color tones, that is, Y (yellow), M (magenta) and C (cyan) images, or four color tones including K (black), are sequentially printed. The color tone to be realized by printing is expressed by adjusting the degree of superposition of yellow, magenta and cyan components.
When the thermal transfer recording apparatus prints yellow components in a yellow-component printing step, the thermal head is operated while rotating the platen to move the printing sheet with respect to the thermal head so that data of the yellow components is printed. In a next magenta-component printing step in which magenta components are printed, the platen is furthermore rotated to restore the printing sheet to the original position so that magenta components are printed similarly to the yellow-component printing process. In a next cyan-component printing step in which cyan components are printed, the platen is furthermore rotated to similarly restore the printing sheet to the original position so that cyan components are printed similarly to the magenta-component printing process. That is, similar printing steps are repeated three times. If an ideal operation is performed, yellow, magenta and cyan dots are printed at appropriate positions so that an appropriate color is reproduced.
However, the structure arranged such that the platen is rotated to physically locate the printing sheet sometimes encounters a fact that the printing sheet cannot completely be restored to the original position when the magenta-component printing step is performed or the cyan-component printing step is performed. In the above-mentioned case, displacement for several microns takes place at the dot position for each color component. Since the yellow, magenta and cyan dots are linearly arranged in a direction in which the heat generating devices are arranged, that is, in the main scanning direction, displacement of the dot position of each color causes linear moire fringes to be generated in the main scanning direction.
Since yellow, magenta and cyan dots are printed in this sequentially order and the half tones are expressed by adjusting the degree of superposition of the yellow, magenta and cyan components, relative displacement taking place between, for example, the yellow dot and the magenta dot results in a dot having a hue different from a required one being unintentionally formed. That is, color balance is disordered and color confusion takes place.
In view of the foregoing, an object of the present invention is to provide a recording method and a recording apparatus capable of preventing generation of moire fringes and color confusion occurring attributable to displacement of recorded dots.


The present invention aims at providing a semiconductor memory device that can be operational in a desired boot block mode, regardless of the original boot block type of the device, by facilitating rewriting of the memory device. A sector address from an outside source is inputted into a sector-address conversion circuit, which converts the sector address into an internal address, and a memory cell array is accessed through an address decoder circuit. Suppose that each of banks of the memory device is configured as a bottom boot type. By converting the sector address by the sector-address conversion circuit such that the sector-address now appears to the outside in the reverse order, each of the banks now functions as a top boot type.

1. Field of the Invention
This invention relates to a semiconductor memory device, a sector-address conversion circuit, an address-conversion method, and an operation method of the semiconductor memory device.
2. Description of the Related Art
Various kinds of memory devices including a flash memory are known. Generally, the first operation at starting of a system, reset operation and the like is performed by reading a read-only boot program and the like from a memory device.
Conventionally, a boot block used as an object for starting of a system occupies a small sector in a memory device, and is located in the high end or the low end of sector addresses (physical addresses) of the memory device (a bottom boot type or a top boot type, respectively, and called a boot block type) according to a requirement specification of the system. The two types are marketed as distinctly individual products.
FIG. 1A shows the top boot type memory device wherein a small sector 11 located at the highest sector addresses of the memory device serves as the boot block area.
FIG. 1B shows the bottom boot type memory device wherein a small sector 16 located at the lowest sector addresses of the memory device serves as the boot block area.
For an STB (set top box), there is a need to write new data while keeping data in a memory currently used in the system. That is, when there is an option service newly added and the like, it is necessary to write data or a program transmitted from a circuit to the memory device, while watching television through a television circuit.
The STB has two memory devices 20 and 25 as shown in FIG. 2. The memory device 20 is rewritten using a program stored in a boot block area 26, keeping data in the memory device 25. Further, the memory device 25 is similarly rewritten using a program stored in a boot block area 21, keeping data of the memory device 20. Thus, two memory devices are used to rewrite contents of the other memory device alternately.
Moreover, as shown in FIG. 3, a memory device that has small sectors 31 and 32 in the sectors of the highest addresses and the lowest addresses, respectively, is also available.
In addition, the boot program is stored in the lowest physical addresses of a memory device when the small sector is located in the lowest addresses of the memory device. Moreover, the boot program is stored in the highest physical addresses of a memory device when the small sector is located in the highest addresses of the memory device.
However, rewriting of the data within the same system and the like always requires to use the same boot block type from design restrictions, and rewriting between memory devices with different boot block types has a problem that it cannot be easily performed.
Moreover, a type of a memory device that has two or more banks, each having a small sector that can be used as a boot block, and rewriting each other is also marketed.
However, a problem with this type is that address areas of the boot block differ (e.g. a bank or some banks are the top boot block type and the other banks are the bottom boot block type), causing difficulties in rewriting the memory device.

Semiconductor memory device, a sector-address conversion circuit, an address-conversion method, and operation method of the semiconductor memory device


An automated or semi-automated process to prepare karyotypes from metaphase cell images with improved accuracy involves the use of deep convoluted neural networks for both chromosome segmentation and chromosome classification.

Chromosome analysis has been the gold standard in genetic diagnosis for decades. Although molecular methods have become important, they do not provide the "global" information on the genetic status of an organism, an organ, or a biopsy. Karyotyping thus remains a procedure that is performed regularly, either as an initial test, e.g., in leukemia diagnostics, or to confirm findings generated through molecular methods (such as after a positive result of a non-invasive, blood based prenatal molecular test).
There is a lot of interest in streamlining the diagnostic procedure of karyotyping, and particularly in speeding up the chromosome classification by the human expert. Moreover, experienced cytogenetic technologists are becoming increasingly difficult to find.
Although various efforts have been made to automate the classification of chromosomes, the reliability of the results have not been satisfactory. The limitations of the results in leukemia diagnosis for instance, can be caused by the poor banding quality of the chromosomes prepared from bone marrow samples. Some protocols require significant effort to prepare or modify chromosome images, such as chromosome straightening as suggested by Sharma et al. Typical error rates of automatic chromosome recognition per cell, based on feature analysis such as intensity profiles along the chromosome axis, are on the order of 65%, meaning that a large fraction need to be manually corrected. Thus, there is a need for more accurate methods for automated chromosome analysis.

Methods for automated chromosome analysis


A radio unit of a radio telephone set is provided with current input connections comprising separate identification inputs through which is indicated the type of phone module, and internal or external power supply thereof, which is connected to the radio unit. A control element in the radio unit is programmed to adjust the operating parameters of the radio unit in accordance with the type of phone module which is connected.

The invention relates to a radio unit for a radio telephone set wherein said radio unit is interconnected with at least one disconnectable phone module.
Cellular or mobile phones are, for various uses, comprised of different combinations of a radio unit and a phone module. A mobile phone, a portable phone, a hand-portable phone and a mobile phone with a separate battery, for example, are involved. A mobile phone with a separate battery is called a bag phone. In certain types of telephones a number of similar batteries with similar voltage limits can be used. The prior art radio telephone can also identify the difference in whether the phone element uses its own battery or if the phone is fed by an external power supply.
Patent application EP 90304320.6. published on Oct. 24, 1990 with the number 394074 discloses a method and apparatus for determining the battery type and for modifying operating characteristics accordingly.
The diversity of different combinations, as well as the costs entailed with short production runs and a larger number of production lines, respectively, are drawbacks in the present cellular phone production.

Radio unit for a telephone set with automatic adjustment of operating parameters based on a connected power module


Methods, apparatus and systems for controlling flow of data between a memory of a host computer system and a data communications interface for communicating data between the host computer system and a data communications network. In an example embodiment, an apparatus includes a descriptor table for storing a plurality of descriptors for access by the host computer system and data communications interface. Descriptor logic generates the descriptors for storage in the descriptor table. The descriptors include a branch descriptor comprising a link to another descriptor in the table.

A conventional data processing network comprises a plurality of host computer systems and a plurality of attached devices all interconnected by an intervening network architecture such as an Ethernet architecture. The network architecture typically comprises one or more data communications switches. The host computer systems and the attached devices each form a node in the data processing network. Each host computer system typically comprises a plurality of central processing units and data storage memory device interconnected by a bus architecture such as a PCI bus architecture. A network adapter is also connected to the bus architecture for communicating data between the host computer system and other nodes in the data processing network via the network architecture. It would be desirable for transfer of data and control information between the host computer system and the network architecture to be facilitated as efficiently as possible.

Controlling flow of data between data processing systems via a memory

International Business Machines Corporation


A microwave incinerator is configured to incinerate waste material. The waste material is installed within a microwave absorbing shroud located in a microwave chamber. The combination of low microwave heat input and a vacuum drawn on the chamber vaporizes the water in the garbage. During this first phase there is no combustion because of the relatively low temperature and the lack of oxygen. Once the material is dry, intense microwave energy is applied to the chamber heating the silicon carbide shroud to an elevated temperature in the range of about 500 to 1000 degrees C. Concurrent with the rapid rise in temperature, air containing oxygen is pumped into the chamber. The hot shroud ignites the material, after which heat is provided is a combination of combustion heat and microwave energy. The temperature is monitored and the microwave energy input is controlled to assure a controlled burn of the waste material.

Garbage disposal is a very serious problem in the United States and in many other areas of the world. Land fills in most urban areas are becoming over burdened and new sites are extremely difficult to establish because people generally do not want them in their communities. Many people own a mechanical garbage disposal unit which grinds up kitchen type garbage which is then flushed down the drain.
Another solution to garbage is incineration. Various types of incinerators have been proposed, and some are in use to treat waste such as radioactive, toxic or other hazardous wastes, but none have gained wide spread use. There has been no significant use of incinerators for residential garbage disposal.
Several incinerator designs have been proposed which utilize a microwave source such as a magnetron to assure combustion of the garbage. Microwaves are very effective at heating water; therefore, this energy source is good for drying the garbage. The absorption of microwaves in other materials varies widely. However, once garbage begins to burn and plasmas are generated the plasmas are very good absorbers of microwave energy.
Silicon carbide is known to be a good absorber of microwave energy. In U.S. Pat. No. 4,937,411, Suzuki proposed the use of a silicon carbide plate at the bottom of one of his combustion chambers for the purpose of absorbing microwaves to increase the heat input into the chamber.
Prior art microwave incinerators are typically complicated, expensive and unreliable. What is needed is a better microwave incinerator low enough in cost and simple enough in operation that it can be made available to the residential market.


A list of program instructions are mapped into memory addresses to form an executable program by simulating their execution in turn so as to determine a memory address of a next program instruction to be executed. That memory address is then examined to determine if a program instruction has already been mapped thereto. If the memory address is empty, then the next program instruction from the list is mapped to that empty memory address and the execution of that next program instruction is simulated and the process repeated. If the memory address is not empty, then the program instruction read from that memory address is simulated again and the process repeated.

1. Field of the Invention
This invention relates to the field of data processing systems. More particularly, this invention relates to mapping program instructions from a list of program instructions into a memory address space to form an executable program.
2. Description of the Prior Art
It is known to generate computer programs in a form in which they can be automatically compiled to form an executable program image. During compilation the computer programs are mapped to memory addresses with branch targets, jump targets and the like being dynamically calculated with appropriate instruction modifications such that the computer program as a whole will execute correctly. Typically, although not always, such computer programs are laid down to form a contiguous program image within the memory space.
Compilers for use in accordance with the above rely upon the computer programs they are to compile being represented in a symbolic and abstract manner, such as assembly language code, such that the compiler can interpret the symbolic representation of the program to generate binary executable program instructions to be stored in the memory. Abstract program representations, such as assembly language, are also easier for most humans writing computer programs to understand and manipulate.
It is also known to produce test programs for the purpose of testing data processing systems by causing them to adopt a broad range of functional states. Such testing can be done for design verification, manufacturing test or other reasons. Such a test program will typically be run or simulated and then the final result compared with an expected result to see if the circuit is behaving as anticipated. The requirements for a test program to execute so as to move the system through a broad range of its possible states places different requirements on the program instructions than are normal. In particular, symbolic representations of the computer program to be used as a test are not really useful since depending upon how these will compile into an executable image the states between which the system will move will vary considerably. One compilation of such a program may produce a suitable test whereas another compilation may not test sufficiently. For this reason, test programs may more desirably be formed in a more specific form in which the various operand values are determined rather than being dynamically selected during compilation. Such programs will behave more predictably and so generate more predictable test behaviour. However, a problem arises in producing executable programs from such test program instructions since a compiler is no longer used and able to deal with the problem of laying out the program instructions into memory and adjusting branches and jumps so that the correct program flow is maintained. This problem is made worse in situations in which it is possible to load the program counter value as this increases the ways in which the program flow can jump and makes such jumps data dependent, e.g. a value is calculated by one instruction and then loaded to the program counter resulting in a jump to the calculated address.

Forming an executable program from a list of program instructions


A fluorometer for sensing the fluorescence of a sample utilizes an optical energy source for exciting a sample to be tested and an optical energy detector for detecting the emitted energy from the excited sample. Drive electronics are used for positioning the sample with respect to the optical components allowing a plurality of sample regions to be tested. A processor is utilized to control the operation of the test in accordance with test instructions and for processing the emitted energy detected from the sample to determine test results. A ROM chip socket accepts a plurality of ROM chips, wherein each ROM chip stores test data sets for one or more test types to be performed. ROM chips can be swapped to allow the fluorometer to be configured and reconfigured to perform a plurality of different tests. A communications interface facilitates the sharing of test information between the fluorometer and external entities.

1. Field of the Invention
The present invention relates generally to fluorometers, and more particularly to a system and method for performing automated fluorescent measurements.
2. Related Art
Conventional medical devices used to perform fluorescent readings are large, dedicated machines. Typical fluorometers are bench-top devices which are not easily transported from location to location. Additionally, conventional fluorometers are not easily capable of being programmed by the user or otherwise configured by the user to perform a plurality of different types of tests. Instead, the conventional fluorometer is factory-programmed to perform a predefined test protocol.
To perform a test using a conventional fluorometer, a laboratory technician obtains a sample. The sample can be a biological fluid, such as blood, serum, plasma, urine, a fecal extract and the like or it can be an environmental sample, such as water, a ground extract, a chemical and the like or it can be an extract of a food product. In the case of a blood sample, the blood is first separated into plasma or serum, which becomes the sample, and cellular fractions using a centrifuge. The sample is then generally deposited into a small test tube that is inserted into the fluorometer. Because the conventional fluorometer can accept several samples, the technician enters an identification of the sample and the location of the test tube into the fluorometer.
Once one or more test tubes containing samples are positioned in the fluorometer, the test begins. Contemporary fluorometers use robotics to pipet the sample and the reagents and to position one or more optical sensors by the sample to obtain the necessary readings. The readings are recorded along with the associated test-tube location designations. The location designation is used to identify the sample.


A drill bit configures hydraulic streams from the bit nozzles for the particular cutting structure to be cleaned based on the cutting structure location and geometry. The projected impingement location for each hydraulic stream projected fluid path is customized for a corresponding roller cone, with each nozzle or nozzle receptacle being individually positioned according to improve cone cleaning. At least two nozzles or nozzle receptacles should differ on the drill bit.

The invention generally relates to rotary cone rock bits. More particularly, the invention relates to rotary cone bits having nozzle arrangements to provide improved cutting structure cleaning.
Roller cone bits, variously referred to as rock bits or drill bits, are used in earth drilling applications. Typically, these are used in petroleum or mining operations where the cost of drilling is significantly affected by the rate that the drill bits penetrate the various types of subterranean formations. There is a continual effort to optimize the design of drill bits to more rapidly drill specific formations so as to reduce these drilling costs.
Rotary cone rock bits attach to sections of drilling pipe that connect together to form a drill string. A rock bit attaches to the end of this drill string and is rotated, drilling a bore hole into the earth. Rock fragments known as drill cuttings are generated at the bottom of the borehole by the cutting and grinding action of the drill bit rotating at the bottom of the bore hole. These rock fragments are carried uphole to the surface by a moving column of drilling fluid that travels to the interior of the drill bit through the center of an attached drill string, and is ejected from the face of the drill bit through a series of jet nozzles, and is carried uphole through an annulus formed by the outside of the drill string and the borehole wall. The drilling fluid also maintains borehole integrity, and cleans and cools the face of the rock bit.
A drill bit is configured with a number of roller cones, typically three, at its bottom that are equidistantly spaced around the circumference of the bit. A layout of a three-cone rock bit is shown in FIG. 1A. A rock bit 10 typically comprises a steel bit body and three cutter cones mounted on legs 14 extending from the bottom of the body. The cones are imbedded with inserts 26 (also described as cutting elements or teeth) that penetrate the formation as the drill bit rotates in the hole. It should is appreciated by those of ordinary skill in the art that there are some inserts or teeth on a roller cone that do not cut because they do not extend adequately from the cone surface. These may be identified by their substantially lower height. The upper end of the body is threaded (not shown) and serves as the pin for assembly of the rock bit onto a drill string for drilling bore holes. The area between the legs on the underside of the body is referred to as the dome 18. It should be noted that in describing the invention, an inventive drill bit may be described as though the central axis of the drill bit is vertical and words like "upper", "lower", "top", "bottom", "above", and "below" should be interpreted with this in mind, unless the context clearly indicates otherwise.
A cutter cone is rotatably mounted on each of the legs 14. A conventional internal structure may be used to mount the cutter cones on the legs. Each cutter cone has a hollow, generally conical steel body 20. The cones have an apex or nose 22 on one end and an opening on the other 24 for receipt of a journal. Each leg has a bearing journal (not shown) extending from it. Each cone is fitted over a journal, i.e., the journal is positioned inside the cone through the cone's opening. Ball bearings or other cone retention system (not shown) hold the cones on the journals. When mounted on the journals, the cones are radially oriented about the bit central axis so that the nose of the cones is closer to the axis than the opening of the cones.
Cutting elements 26, such as teeth or inserts, are pressed into holes or machined on the external surface of the cones. Unless noted otherwise, the terms teeth and inserts are used interchangeably herein. Cutting elements 26 provide the drilling action by engaging subterranean rock formation as the rock bit is rotated. The inserts may be any type or shape so long as they cut formation. For longer life, the inserts may be tipped with a super hard material (e.g. polycrystalline diamond).
The cutting elements are typically arranged in annular rows on the cone. Although nomenclature varies across the industry, the row that cuts the largest diameter within the bore of the hole is referred to as the gage row 28. The gage row cuts to about gage, i.e. the full diameter of the drill bit. The term "about" is used in this context because due to design or wear the inserts may cut slightly over or under gage but not to an extent that affects the action of the drill bit. For example, a gage row insert may extend a sixteenth of inch short of the gage diameter under certain situations and still be effective. The next cutting closest row is the row that is referred to as the drive (or off-gage) row 27. This row typically generates the highest torque on the cone. The row closest to the apex of the cone is referred to as the nose row 30. For cones comprising a single central cutting element on their apex, the nose row is the central cutting element.
The drawing of FIG. 1A is schematic in its illustration of the inserts. The inserts are illustrated on each cone in apparently overlapping positions. These inserts represent the inserts on all three of the cones projected around to the planes illustrated. This illustrates the complete coverage of the bore hole bottom by inserts during a complete revolution of the roller cones. In actuality, about ⅓ of the insert rows are on each cutter cone and the insert rows are arranged on the individual cones so that they do not interfere with rows of inserts on the adjacent cones.
The center jet of FIG. 1A can be used to illustrate the general construction of a nozzle. A jet assembly 32 is located in a nozzle receptacle bit body dome 18. In some drill bits, an outer sleeve 71 is welded into the dome of the bit body. The jet assembly preferably has a nozzle 34 with a shoulder that seats on a shoulder 72 in the sleeve and a jet bore axis (not shown). An inner retainer sleeve 66 is threaded into the outer sleeve for securing the jet against the shoulder. An O-ring 74 seals between the outer sleeve and the jet body to prevent washout around the jet body.
Generally, between each pair of cones is a nozzle receptacle with an installed erosion resistant nozzle that directs the fluid from the face of the bit to the hole bottom to move the cuttings from the proximity of the bit and up the annulus to the surface. The placement and directionality of the nozzle receptacles and nozzles, as well as the nozzle sizing and nozzle extension, significantly affect the rate of penetration for the drill bit and bit life.
Referring to FIG. 1B, nozzle positioning for a three cone rock bit is shown. In general, a three cone bit has three symmetrical legs, each with a journal. Each of the legs takes up a 120° section, with each of the three legs in a three cone rock bit being 120° apart. The journals, even though they have journal angle and offset associated with them, are also 120° apart, projected on a plane normal to the bit axis. For a two cone bit, the legs and journals can be apart by 180° or 165° or any other degree. The angular difference between the journal axes (at the leg centers) can be termed as the "phase angle" or phase angle difference. Journal axes 102, 104, 106 are each offset radially from bit central axis 108 by a distance defined by a circle 110. By virtue of even spacing around the drill bit, each of the three journal axes are spaced 120 degrees from its neighbors. Three nozzle receptacle locations are shown: nozzle-1 112, nozzle-2 114, and nozzle-3 116. Each nozzle receptacle 112, 114, 116 is located midway between the adjacent journal axes 102, 104, 106. This results in a 120 degree spacing between the nozzle receptacles.
The amount of energy available at the bit is generally dictated by factors external to the bit such as the drilling rigs' available hydraulic energy, drill pipe type, bottom hole assembly (BHA) configuration and drill depth. However, once the available energy for the rock bit is determined, properly configuring the hydraulics of the bit for the specific application can significantly affect the rate of penetration (ROP) of the bit in the formation.
The optimal placement, directionality and sizing of each nozzle can change depending on the bit size and formation type that is being drilled. For instance, at the very soft end of the formation spectrum there is a strong tendency for clay minerals to adhere to the teeth or inserts of bits. The adhesion of formation to teeth or inserts is commonly referred to as "bit balling". As is known in the art, bit balling describes the packing of formation between the cones and bit body, or between the bit cutting elements, while cutting formation. When it occurs, the cutting elements are packed off so much that they don't penetrate into the formation effectively, tending to slow the rate of penetration for the drill bit (ROP). For example, "gumbo" in the US Gulf Coast area has a sticky nature and adheres to rock bit cutting structures. It must be removed efficiently to maintain reasonable penetration rates.
In harder clays and shales, cuttings can become impacted or "balled up" between the teeth or inserts of the cutting structures. When formation sticks to cones or is impacted between cutting elements it limits insert/tooth penetration. Also, formation packed against the cone-shell closes the flow channels needed to carry other cuttings away. This promotes premature bit wear. In either instance, fluid directed toward the cones can help to clean the inserts and cones, allowing them to penetrate to a greater depth, maintaining the rate of penetration for the bit. Furthermore, as the inserts begin to wear down, the bit can drill longer since the cleaned inserts will continue to penetrate the formation even in their reduced state.
In part to combat bit balling, and in part to allow for larger cones, the cutting elements on different rolling cones often are designed to intermesh. Intermeshing reduces bit balling. As a cutting element of one cone intermeshes between the cutting elements of another cone, it dislodges balling between the cutting elements. Having the cutting elements intermesh also allows the diameter of the cones to be larger, providing for a larger bearing surface which results in a more durable cone. One aspect of intermeshing is different spacing between various rows of inserts on the cones. Of particular interest, the spacing of the gage row and drive row vary amongst each of the roller cones.
FIG. 2A is a bottom view of a hypothetical three cone rock bit (not to scale). First nozzle receptacle 102, second nozzle receptacle 104, and third nozzle receptacle 106 are located between three roller cones 108, 110, and 112. Fluid columns 114, 116, 118 can be seen projecting from respective nozzle receptacles. Although it is to be understood that the jet of fluid ejected from each nozzle receptacle behaves in a complicated manner, to simplify understanding of the invention each fluid discharge is depicted as a column to emphasize its direction. It should also be noted that a revolved surface can be seen around each row of cutting elements rather than the individual cutting elements themselves.
FIGS. 2B–2E (not to scale) show the relative positions of the fluid columns to the roller cones. FIG. 2B shows nozzle fluid stream 118 in proximity to cone 112. Also shown is gage row 202 and drive row 204. FIG. 2C shows nozzle fluid stream 116 in proximity to cone 110. Also shown is gage row 206 and drive row 208. FIG. 2D shows nozzle fluid stream 114 in proximity to cone 108. Also shown is gage row 210 and drive row 212. FIG. 2E shows a composite view of FIGS. 2B–2D. It can be seen that the three fluid streams, 114, 116, 118, appear identically located when superimposed with respect to each fluid stream's respective roller cone. Each fluid stream is about the same distance from the gage rows (or more precisely, the surface of revolution for the gage row inserts) 202, 206, 210 on the respective roller cone. It can be seen that the spacings from the inserts on other rows 204, 208, 212 on the roller cones to the corresponding fluid stream varies significantly from cone to cone, however.
Numerous efforts have been made by drill bit designers to solve the problem of bit balling yet the problem persists. Known drill bit designs vary placements, directionality and sizing of nozzles and fluid streams in an attempt to maximize performance and rate of penetration of drill bits in various formations. However, the type, angle placement and specifics of nozzle receptacles for any given bit are the same. This may be due to the manner in which drill bits are typically manufactured. Typically, a drill bit is assembled from three identical portions. These portions are welded together to form the drill bit body. The roller cones are then attached to the bottom of the bit body. Further, perhaps to avoid installation problems at the drilling site, the nozzles installed in each nozzle receptacle are typically identical. However, while the relative location of the nozzle receptacles and nozzles may therefore be the same, the roller cones on the bit bottom are not. The spacing of the rows of inserts on each roller cone differs from the spacing of the rows of inserts on its neighboring cones because of intermeshing. As a result, in a three cone rock bit, the conventional hydraulic configuration either cleans one cone very well and compromises cleaning of the others, or a less-than-optimum configuration exists to clean cutting structures on all three cones.
Bit balling remains a problem. Ideally, a drill bit could be designed that reduces the effects of bit balling while drilling the borehole. In at least some embodiments, this drill bit would not require complicated installation of varying, differently sized, or differently configured nozzles at the drill site.

This patent is subject to a terminal disclaimer.


An air data system includes an air data probe and a surface acoustic wave (SAW) sensor attached to the air data probe for detecting particulate accumulation. The air data probe includes a probe head, a strut connected to the head, and a mounting plate connected to the strut. The probe head has an inlet, an interior surface extending from the inlet, and an exterior surface extending from the inlet.

The present disclosure relates generally to air data probes, and in particular, to ice detection systems for air data probes.
Air data probes are installed on aircraft to measure air data parameters. Air data parameters may include barometric static pressure, altitude, air speed, angle of attack, angle of sideslip, air temperature, total air temperature, relative humidity, and/or any other parameter of interest. Air data probes may be, for example, pitot probes, pitot-static probes, total air temperature probes, or angle of attack sensors.
Air data probes are mounted to an exterior of an aircraft in order to gain exposure to external airflow. External airflow may contain water or ice particles that can collect and freeze onto the air data probe. Ice growth on an air data probe can interfere with the accuracy of the air data probe output.

Surface acoustic wave sensors for air data probes


Disclosed is a function masking apparatus in a symmetric cryptographic algorithm for preventing side channel attacks, including: a controller creating lookup tables for one or more internal functions included in a high security and light weight (HIGHT) algorithm, respectively based on a plurality of non-linear functions, a plurality of linear functions, and a plurality of constants which are randomly generated; and a storage unit storing the lookup tables for one or more internal functions included in the generated HIGHT algorithm.

Side channel attacks are a cryptograph analysis technique based on a grey-box model that can collect various pieces of additional information generated while a cryptographic module is driven unlike a cryptography analysis method based on a theoretical black box model in the related art.
All intermediate values used for a cryptographic operation need to be randomized in order to implement a cryptographic algorithm so as to be safe to the side channel attacks. As a result, most side channel attack corresponding cryptographic algorithms are based on a data masking technique for randomizing the intermediate value. The data masking technique has performance enough to be actually used when certain degree of performance deterioration is considered for a primary differential power analysis attack response. However, when the data masking technique is applied so as to prevent even higher order differential power analysis attacks, performance deterioration increases by hundreds of times as compared with a standard cryptographic algorithm without side channel prevention, and as a result, it is impossible to use the data masking technique in an actual system.

Function masking apparatus in symmetric cryptographic algorithm for preventing side channel attacks and method thereof

ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE


A clutch having high engaging force and featuring of smooth operation, wherein clutch weights that are biased by return elements are subject to thrusting force caused by constraint sections of a main driving plate that receive and convert torque from an engine into the pressing action against engaging slots defined in the clutch weights so as to gain enhanced engaging force even when the minor difference or error existing on the response time of the clutch weight or the strength of the return elements and also provides anti-reversal function to reduced the oscillation and let the power output more smooth and more stable. Accordingly, slippage of clutch and wear of the clutch wear pad are both reduced and temperature rise of the wear pad is also reduced.

(a) Technical Field of the Invention
The present invention relates to a clutch that enhances engaging power, and in particular to a clutch of high engaging power and featuring stable engagement, which increases the engaging power of each clutch shoe to smoothen and stabilize power transmission.
(b) Description of the Prior Art
A centrifugal clutch is widely used in an automatic transmission mechanism of a motorcycle. The centrifugal clutch functions to reflect the rotational speed of a driven pulley to cause clutch weights that are in pivotal connection with a base to expand the clutch weights, in response to the increasing of rotational speed, for causing the wear pads to engage a rim of a driven disk and thus transmitting power to a driven shaft for driving wheels of motorcycles forward. When the rotational speed is reduced, the clutch weights are moved inward and closed to each other, and the transmission of power to the driven shaft is cut off. To allow the clutch weights to reflect the variation of rotational speed and to induce effective engagement, each clutch weight is provided with tension spring (return element) on opposite sides of the pivotal point and connecting between adjacent clutch weights. Timing of expansion/closing of the clutch weights is determined by the tension of the spring.
Theoretically, every two adjacent clutch weights are constrained by the inter-connecting spring. The response characteristics of each clutch weight in action and angle of expansion/closing operation due to outward movement caused by rotation can be made the identical if the tension of all the springs are the same. However, in practice, the base is often in a non-constant speed rotation due to the fact that the rotational speed of the driven pulley is subject to variation by different operations of the acceleration pedal in response to different driving conditions. This makes the centrifugal force of each clutch weight exhibiting difference in response timing. Thus, during the outward expansion and inward closing process, the clutch weight is subject to unstable expansion, leading to oscillatory phenomena of engaging, which causes the transmission of power unstable.