Disclosed are methods, circuits, apparatuses and systems for providing power to a dynamic load such as a non-volatile memory array. According to embodiments, a voltage source may be adapted to generate and output a supply current at substantially a target voltage through a regulating transistor whose channel is in series between an output terminal of said charge pump and an input terminal of said NVM array. A discharge circuit branch coupled to an output terminal of the regulating transistor may be adapted to drain away current from the regulating transistor output terminal when a voltage at the regulating transistor output terminal exceeds a first defined threshold voltage. A bulk regulating circuit branch coupled to a bulk of the regulating transistor may be adapted to reduce a bulk-voltage of the regulating transistor when a voltage at the regulating transistor output terminal exceeds a defined threshold voltage.

Non-volatile memory ("NVM") cells are fabricated in a large variety of structures, including but not limited to: (1) poly-silicon floating gate, (2) Non volatile MIRRORBIT, (3) Silicon-Oxide-Nitride-Oxide-Silicon ("SONOS"), and others. FIGS. 1A through 1C show cross-sectional views of several different NVM cell structures. Although each NVM cell structure has unique properties and operating characteristics, basic operation of NMV cells, sets or arrays of NVM cells, and devices based on these NVM cells is fundamentally similar. NVM cells are programmed (i.e. charged or discharged) to a logical state correlated with information (e.g. bits) they are to store and read by detecting their threshold voltages (Vt).
Information is stored on NVM cells by regulating and altering the NVM cell's logical state, which logical state may be defined and determined by adjusting and later reading its Vt—the gate to source voltage at which the NVM cell begins to conduct non-negligible current. Different threshold voltage ranges are associated with different logical states, and a NVM cell's threshold voltage level may be correlated to the amount of charge (e.g. electrons) stored in a charge storage region of the cell. FIG. 2A shows a voltage distribution graph depicting possible threshold voltage distributions of a binary non-volatile memory cell, wherein vertical lines depict boundary voltage values correlated with each of the cell's possible states. Cells having Vt lower than EV level are said to be erased verified. Cells having Vt higher than PV are said to be program verified. Since NVM cells may lose some amounts of stored charge, a read verify level above which the cell is also considered programmed, may be set below a program verify level. A Program sequence of programming pulses may be used to drive the Vt of a cell higher than PV, while an erase sequence may drive the cell's Vt lower than EV.
FIG. 2B shows a voltage distribution graph depicting possible threshold voltage distributions in the charge storage region of a multi-level non-volatile memory cell ("MLC"), wherein one set of vertical lines depict boundary values correlated with each of the cell's possible Program Verify Threshold Voltages (PV00, PV01, etc.), another set of vertical lines depict boundary values correlated with the Read Verify level of each of the cell's possible Program states (RV00, RV01, etc.), and yet another set depict boundary lines for Intermediate Program Verify voltages (PVI 00, PVI 01, etc.) associated with each of the states.
The amount of charge stored in a charge storage region of an NVM cell, may be increased by applying one or more programming pulses to the cell. While the amount of charge in the cell may decrease by applying an erase pulse to the NVM cell which may force the charge reduction in the cell's charge storage region, and consequently may decrease the NVM's Vt.
Most methods of operating NVM cells (e.g. programming, reading, and erasing) require one or more reference structures, such as reference cells, to generate the reference levels against which the Vt of a cell is compared. Each of the one or more reference structures may be compared against a memory cell being operated in order to determine a Vt, condition or state of the memory cell being operated. Generally, in order to determine whether an NVM cell is at a specific state, for example erased, programmed, or programmed at one of multiple possible program states within a multi-level cell ("MLC"), the cell's threshold level is compared to that of a reference structure whose threshold level is preset and known to be at a voltage level associated with the specific state being tested for.
Comparing the threshold voltage of an NVM cell to that of a reference cell is often accomplished using a sense amplifier. Various techniques for comparing an NVM threshold voltage against those of one or more reference cells, in order to determine the state(s) of the NVM's cells, are known. The most common technique includes applying the same terminal voltages and supply currents to the NVM being read and to a defined reference structure (e.g. reference cell which Vt is known) and determining which starts conduct first. FIG. 3 shows a functional block diagram of an NVM device including: (1) an array of NVM cell; (2) a set of reference structures, which structures could be from within the array; (3) one or more voltage sources for applying voltages and providing current to both the NVM cells and array structures; and (4) cell evaluation circuits(s) such as sense amps. FIG. 4 shows a composite circuit and current flow diagram depicting how applied voltages and currents may induce current flow through individually selected NVM cells within an NVM array during a reading/sensing phase.
Since the distance and number of branches through which current from an array driver may need to flow is highly variable depending upon the location and number of selected NVM cells on the array for a given operation, the resistance and capacitance experienced by the array driver likewise greatly varies from operation to operation. FIG. 5 illustrates a conventional drain driver topology along with a corresponding voltage graph indicating how the voltages transition at different points along the bit-line path during a sensing operation. The graphs also illustrate a delay and a sensing voltage error in the sensing operation introduced do to capacitance and/or resistance of the bit-lines.

Methods circuits apparatuses and systems for providing current to a non-volatile memory array and non-volatile memory devices produced accordingly


An instantaneous power density profile (PDP) is generated by dynamically switching between signals from two or more antennae, each for a variable number of signal samples. A variable number NC of samples are correlated with a known chip code, the correlations phase-coherently accumulated, and a number NNC of such coherent accumulations is accumulated non-coherently for each of a plurality of delay values. The parameters considered in determining the dynamic switching pattern may include values of NC and NNC, how often and at which point in the PDP generation process to switch between antennae, and other factors, such as the velocity of a transmitter. The coherent accumulations from each antenna may be weighted in response to the signal quality of the respective antenna, and the weighted coherent accumulations accumulated non-coherently.

Wireless communications systems are widely deployed, providing a variety of data and voice communication services to mobile subscribers. In Code Division Multiple Access (CDMA)-based systems, e.g. WCDMA, individual channels are formed by frequency-spreading individual communication signals with orthogonal or nearly orthogonal codes, and transmitting a plurality of spread signals simultaneously in the same broad frequency band. A receiver then correlates a received signal with a particular spreading code to recover the corresponding communication signal, and treats all other signals in the band as noise.
In wireless systems, the physical channel between terminals is formed by a radio link. In most cases, many different propagation paths exist between the terminals, due to reflections in the environment. The plurality of propagation paths gives rise to a multipath channel carrying several resolvable components. Because CDMA channels are extracted at a receiver by correlating a received signal with a known spreading code, the receiver performance is improved by utilizing the signal energy carried by many multipath components. This is traditionally achieved by using a RAKE receiver.
The RAKE receiver derives its name from its rake-like appearance, wherein multiple, parallel receiver fingers each receive the multipath signal. Each finger is provided with a reference copy of the spreading code that is delayed equally to the path delay of a corresponding multipath component. The finger outputs are then coherently combined to produce a symbol estimate. In this manner, the RAKE receiver utilizes multipath reception to improve the Signal-to-Noise Ratio (SNR) of the received multipath signal. RAKE receiver performance is optimized if the signal energy from all paths is utilized. To provide the properly delayed spreading code to each finger, the RAKE receiver requires knowledge of the multipath delays and the values of the channel impulse response for all paths.
The multipath delays of the radio channel may be found in a number of different ways. A traditional and efficient solution is based on the power delay profile (PDP) of the multipath channel. The PDP is produced by performing a sequence of correlation operations for each delay of interest, and indicates the detected signal energies at each delay. The PDP may then be inspected to determine the exact delays of the physical paths, possibly after additional processing, so that these delays may be provided to RAKE fingers. A known way to generate the PDP is to correlate the received sample sequence with a reference pilot channel (CPICH) chip sequence that is appropriately delayed. Each correlation result produces a PDP value for the given delay.
Destructive interference among multipath signal components gives rise to a phenomenon known as fast fading. For example, if two signal components arrive at an antenna along paths that differ in length by a half wavelength (or multiple thereof), they will be 180° out of phase, and will cancel each other out. Due to fading, the instantaneous PDP—one generated in a single activation period or PDP measuring period—may not indicate the presence of all the physical propagation paths, but only a subset. If the instantaneous PDP were used for RAKE finger placement without further processing, some positions or delay regions containing signal energy may not be accounted for, degrading the RAKE receiver's performance.
In order to avoid ignoring some of the paths, instantaneous PDPs may be averaged with previously calculated PDPS, in order to mitigate the fast fading effects. By using the filtered PDP, all signal paths that are physically present will be considered by the RAKE receiver, even if some of them happen to be invisible during the activation period producing the most recent instantaneous PDP. The averaging time constant must be chosen as a compromise between effectively mitigating fast fading and the ability to track the changes in the underlying path delays. Filtering that is too slow may fail to react to changes in the path profile, such as when a moving mobile terminal turns a corner and transmitted signals encounter a different reflection environment. On the other hand, filtering that is too fast may not sufficiently mitigate fading effects.
In addition to path searching, the PDP is also used for signal power measurements to be reported to the network, in order to aid the network in mobility management, such as handover decisions. The Received Signal Code Power (RSCP) and Received Signal Strength Indication (RSSI) metrics are computed based on the PDP. For the reporting purposes, the instantaneous PDP is used, since the reports must reflect the instantaneous fading state, not the average delay profile properties. Similar PDP computation is also required for the cell search process, when detecting the presence and the signal strength of other cells in the neighborhood of a mobile terminal.
A variety of advanced receiver types have been developed to improve the RAKE receiver performance. One such advanced receiver type is dual-antenna receiver, where a signal is received via two separate antennas, each having a separate RF and receiver front-end processing branch (e.g., DAC, filter, and the like). If the two antennae and receiver branches are sufficiently separated (both spatially and electrically), the fading effects, noise, and interference signal components on the two branches, as seen by the RAKE receiver, are substantially uncorrelated. A dual-antenna RAKE receiver exhibits improved performance due to the array gain (more signal energy is received) and the diversity gain (the probability of deep fades is reduced). As a result, the block error rate performance of the receiver is improved.
Just like the single-antenna receiver, a dual-antenna RAKE receiver requires knowledge of the multipath delays. On a mobile terminal, the receiver antenna separation is sufficiently small that the underlying delay profile from the transmit antenna to both receiver antennae is identical. Therefore, the same path search operation appropriate for a single-antenna receiver could, in principle, be utilized, whereby only one antenna input signal is used to produce the PDP. The long-term averaged, or filtered, version of this PDP would be applicable to both antenna branches. On the other hand, the availability of two (almost) independently faded input signals from the two receive antennas allows the effective probability of deep fades for the paths to be reduced. That is, for a given path to be invisible at a given time instant, it must be faded down at both antennae simultaneously—an outcome having a considerably lower probability than a fade at one antenna only. Accordingly, if both antennae are utilized, heavy filtering of the instantaneous PDP is not necessary and the dynamic tracking of the path delays may be improved.
Several receiver configurations and operating methods are known for generating a delay profile for a dual antenna receiver. As mentioned above, the signal from only one antenna may be used to generate a PDP that is used for signals from both antennae in a dual-antenna RAKE receiver, filtering the PDP to mitigate the effects of fading. This approach has the advantage of requiring only one PDP generation circuit, but requires long-term averaging to produce a fading-independent average PDP. In addition, the instantaneous PDP from the second antenna is not available for the power measurement reports.
An alternative configuration utilizes two parallel PDP generation circuits operating simultaneously, with each generating an instantaneous PDP from the signal received at a different antenna. The two instantaneous PDPs may then be combined to generate a composite PDP. In this arrangement, an instantaneous PDP is available for both antennae for reporting power measurements, and a shorter averaging period is required for the filtered PDP due to the reduced probability of simultaneous deep fading. However, this configuration requires either two separate PDP generation circuits, or a single PDP generation circuit having twice the processing speed.
Still another configuration utilizes two antennae and two receiver front-end processing circuits, and one PDP generation circuit. The PDP generation circuit considers the samples from each antenna alternatively—on either a per-activation period or per-sample basis—and averages the results. This configuration requires only a single PDP generation circuit and reduces the filtered PDP averaging time. However, if the signals are switched on a per-activation period basis, the instantaneous path profile and the signal quality at the two antennae may differ and the input into the PDP averaging does not change smoothly, resulting in fluctuations of the averaged PDP. Additionally, the instantaneous PDP for one antenna will always be out of date. If the signals are switched on a per-sample basis, excessive data loss may occur, as some data is lost in each switching action due to the non-zero delay spread.

Efficient delay profile computation with receive diversity


The upper block 12 contacts the bearing block 20, and the bearing block 20 is coupled to the upper plate 21. The upper block 12 has a protruding part 22 on the upper surface that is worked into a convex surface with a radius of R1, and the bearing block 20 has a recessed part 23 in the undersurface that is worked into a concave surface with a radius of R2 (R2>R1). As a result of such a construction being used, the pressing surface of the upper pressing plate 15 always conforms to the surface of the quartz crystal substrate 11 during pressing, so that a uniform load is applied to the quartz crystal substrate 11. As a result, the surface of the quartz crystal can be uniformly pressed in the hot pressing method.

A quasi-phase matched wavelength conversion optical element has been proposed in which a periodic polarization inversion structure is realized by applying a stress to quartz crystal (SiO2), which is a paraelectric material, in the vicinity of the α-β phase transition temperature, so that a periodic twin structure is created (S. Kurimura, R. Batchko, J. Mansell, R. Route, M. Fejer and R. Byer: 1998 Spring Meeting of the Japan Society of Applied Physics Proceedings 28a-SG-18). This is a method in which a quasi-phase matched crystal based on quartz is manufactured by utilizing the twin crystal of quartz to achieve a periodic inversion of the sign of the nonlinear optical constant d11, and this quasi-phase matched crystal is used as the quasi-phase matched wavelength conversion optical element.
In the case of quartz, the short absorption edge is a wavelength of approximately 150 nm, and ultraviolet absorption at wavelengths shorter than 200 nm is almost negligible compared to the case of nonlinear optical elements using conventional birefringence phase matching (β-BaB2O4 and CsLiB6O10, etc.) or nonlinear optical elements using the quasi-phase matching of ferroelectric materials (LiNbO3 and LiTaO3, etc.). Furthermore, this also has the following special feature not seen in conventional nonlinear optical elements: namely, there is a possibility of generating, with a high efficiency, light with a wavelength of approximately 193 nm, which is comparable to the light of an ArF excimer laser, by second harmonic generation. By setting the period at several microns to several tens of microns, it is possible to use the twin structure as a practical wavelength conversion device. A semiconductor exposure apparatus using this quasi-phase matched quartz crystal has been proposed (Japanese Patent Application Kokai No. H2002-122898.
Initially, a method in which a periodic Cr film is formed on the surface of a quartz crystal substrate using lithographic and thin film formation techniques, and the temperature is elevated to around 550° C., so that thermally-induced stress is applied utilizing the in-plane stress arising from the difference in linear thermal expansion coefficient between the quartz crystal and Cr, was proposed as a method for manufacturing a periodic twin structure in a quartz crystal (S. Kurimura, R. Batchko, J. Mansell, R. Route, M. Fejer and R. Byer: 1998 Spring Meeting of the Japan Society of Applied Physics Proceedings 28a-SG-18). In this method, the crystal axes are inverted only in the portion where the Cr film is formed, so that a periodic twin structure is produced.
In this method, however, since a stress component that is parallel to the plane of the quartz crystal substrate is used, stress is localized in the vicinity of the surface of the crystal, so that a portion with inverted crystal axes is formed only to a depth of a few microns from the surface of the crystal. Consequently, since a periodic twin structure which extends into the interior portions, i.e., a periodic twin structure with a large aspect ratio, is not obtained, the realization of a bulk optical element that can be used for the wavelength conversion of laser light is impossible.
The hot pressing method has been proposed as the method for solving such problems (S. Kurimura, I. Shoji, T. Taira, M. Fejer, Y. Uesu and H. Nakajima: 2000 Fall Meeting of the Japan Society of Applied Physics Proceedings 3a-Q-1) In this method, a periodic step structure is formed on the surface of one side of a quartz crystal substrate, this quartz crystal substrate is clamped between heater blocks from above and below, the temperature of the quartz crystal substrate is elevated, and pressure is applied at the point in time at which this temperature reaches a desired temperature. In this case, since stress acts only on the portions corresponding to the protruding parts of the step structure, the crystal axis is inverted only in these portions. These portions with inverted crystal axes grow to the interior of the crystal and are thus propagated into the crystal, so that a periodic twin lattice that penetrates greatly in the direction of depth can be manufactured. Specifically, stress is concentrated only in the protruding portions, and twins are generated from these areas; these twins gradually grow into the interior, so that a twin structure with a large aspect ratio is manufactured.
An example of such a quartz crystal substrate in which a step structure is formed on the surface of one side will be described with reference to FIG. 4. A step structure is formed on the surface of one side of a quartz crystal substrate 1; as a result, protruding parts 2 that have a solid rectangular shape are formed at a specified interval. These protruding parts 2 have a specified width in the left-right direction in the figure, and the plurality of protruding parts 2 are formed at a spacing that is the same as this width in the left-right direction in the figure. The protruding parts 2 have a rectangular solid shape that is long in the direction of depth in the figure. The direction parallel to this longitudinal direction is taken as the direction of the a axis. Naturally, the a axis is perpendicular to the normal of the quartz crystal substrate 1.
The direction of the c axis of the quartz crystal is perpendicular to the a axis; however, this c axis is slightly inclined with respect to the normal direction of the quartz crystal substrate 1, as described by S. Kurimura in the May 2000 issue of the Journal of the Japan Society of Applied Physics. Specifically, the quartz crystal substrate 1 is cut so that the normal and the c axis form a slight angle. The reason for this is that the component of an elastic compliance tensor s1123 is used in a procedure in which a periodic twin structure is manufactured by the stress application of the inter-twin energy difference. Twins tend to be generated as this angle increases; in actuality, however, this angle is kept to an angle of approximately 10 to 20 degrees.
As is shown in the figure, the light is incident from the end surface of the quartz crystal substrate 1, and the direction of polarization is the same direction as the direction of the a axis. The light whose wavelength is converted inside the quartz crystal substrate 1 is emitted from the end surface that is located on the opposite end from the incident surface.
An example of the method for manufacturing the protruding parts 2 shown in FIG. 4 will be described below. First, a Cr film is formed to a thickness of approximately 100 nm on the surface of the quartz crystal substrate 1 by a sputtering method. The surface of this film is coated with a positive type resist, and the portions other than the portions that will form the protruding parts 2 are exposed and developed using a semiconductor exposure apparatus such as an i-line stepper. Next, the Cr film is fused and removed using the remaining resist as a mask. Then, wet etching is performed by means of hydrofluoric acid using the remaining resist film and Cr film as a mask, so that a step structure with a depth of about a few microns is manufactured. As a result, a quartz crystal substrate 1 is completed which has a step structure with protruding parts 2 such as those shown in FIG. 4 formed on the surface. Furthermore, the Cr film may either be stripped or not stripped prior to pressing.
It is convenient in a wavelength conversion device that the angle between the c axis and the normal of the quartz crystal substrate be as small as possible; however, the stress required for twin formation is increased in this case. Accordingly, as was described above, the quartz crystal substrate is cut so that the angle between the c axis and the normal of the quartz crystal substrate is an angle ranging from a few degrees to approximately 20 degrees.
FIG. 5 shows a schematic diagram of an example of a pressing apparatus that applies temperature and pressure to such a quartz crystal substrate. This is basically a pressing apparatus comprising four supporting columns 41, an upper block 42 and a lower block 43. The upper block 42 is attached to an upper plate 44, and the upper plate 44 is fastened in place by being clamped by nuts from both sides of the supporting columns 41. The lower block 43 is attached to a lower plate 45, and the lower plate 45 is mounted on a hydraulic cylinder 46. The lower plate 45 and lower block 43 are caused to move upward and downward by the raising and lowering of the piston of the hydraulic cylinder 46, so that a pressing force is generated. A load gauge 47 is disposed between the hydraulic cylinder 46 and lower plate 45, so that the value of the applied load can be monitored.
Respective heaters 48 are attached to the upper block 42 and lower block 43, and are covered by an adiabatic plate (e.g., Hemisul (trademark)) except for the pressing surfaces. The upper block 42 and lower block 43 are respectively made of SUS304, and the pressing surfaces of these blocks are precisely polished to a flatness of approximately 3 μm. Holes are formed in the upper block 42 and lower block 43 from the side surfaces, and the heaters 48 are inserted into these holes. Furthermore, thermocouples (not shown in the figure) used for temperature control are inserted into the side surfaces of the upper block 42 and lower block 43, and these thermocouples are connected to a temperature adjustment device (not shown in the figure). This temperature adjustment device is constructed so as to operate the current that flows through the coils of the heaters 48 by PID control; as a result, the pressing surfaces of the upper block 42 and lower block 43 can be elevated to a desired temperature.
A combination of air pressure and hydraulic pressure is used to control the pressing load. Air at a pressure of several hundred MPa is supplied to an electrical air regulator 49 which can control the flow rate by means of voltage. A voltage from a function generator 50 that can generate arbitrary voltage patterns with respect to time is supplied to the electrical air regulator 49.
The air that is generated by this electrical air regulator 49 is supplied to a hydraulic pressure conversion amplifier 51. This hydraulic pressure conversion amplifier 51 has a 36-fold pressure amplification function. The hydraulic pressure of the hydraulic pressure conversion amplifier 51 is converted into a load by being supplied to the hydraulic cylinder 46, so that a maximum pressing load of approximately 10 kN can be obtained.
A quartz crystal substrate 52 of the type shown in FIG. 4 is placed on top of the lower block 43. In a state in which the lower plate 45 and lower block 43 are raised so that the quartz crystal substrate 52 is clamped by the upper block 42 and lower block 43, the temperature is elevated to the vicinity of the twin transition temperature of the quartz crystal; then, when the desired temperature has been reached, a stress is generated in the surface of the quartz crystal by applying the pressing load described above to the surface of the quartz crystal substrate 52. A desired stress waveform can be obtained in the tracking ranges of the air pressure and hydraulic systems described above by varying the voltage pattern that is generated by the voltage generating device 50.
The quartz crystal substrate 52 has the structure described above, and has a size ranging from several millimeters to several tens of millimeters. Furthermore, after twins are generated at one time by using a wafer with a diameter of several inches or so, these twins can also be cut into smaller segments. The thickness of the quartz crystal substrate 52 is set at approximately 0.1 millimeters to several millimeters so that utilization as a bulk optical element is possible.
Both surfaces of the quartz crystal substrate 52 are polished with high precision, thus ensuring the degree of parallel orientation of both surfaces of the substrate and the surface precision of the respective surfaces so that the mean wave aberration is approximately 0.03λ (λ=0.638 μm) or less. In the case of quartz crystal, this corresponds to a surface precision of approximately 0.045 μm, which is sufficiently fine compared to the steps formed in the quartz crystal surface described above.
Conventionally, as was described above, wet etching by means of hydrofluoric acid has been used as a method of forming steps in quartz crystal. However, in the case of wet etching using hydrofluoric acid, the side surfaces are also removed in addition to etching in the direction of depth; accordingly, especially in cases where a twin structure with a short period is formed, steps are not formed with the same period as the mask. Furthermore, since etching proceeds to a greater extent in the direction oriented along the c axis, the following problem also arises: namely, the depth that is removed varies according to the angle of the c axis with respect to the normal of the quartz crystal substrate.
Furthermore, in the case of a pressing apparatus such as that shown in FIG. 5, the upper pressing surface and lower pressing surface must be parallel in order to apply stress in a uniform manner to the quartz crystal substrate in which both surfaces are being planarized more or less parallel to each other. Moreover, the surface flatness of the respective pressing surfaces must be sufficiently fine compared to the step depth (about a few microns) on the surface of the quartz crystal substrate.
In the case of the conventional pressing apparatus shown in FIG. 5, the lower plate 5 to which the lower block 43 is attached slides along the supporting columns 41, so that the pressing surface of the lower block 43 cannot be adjusted. Accordingly, in order to adjust the degree of parallel orientation of the upper pressing surface and lower pressing surface, it is necessary to move the upper plate 44 to which the upper block 42 is attached. The upper plate 44 is fastened to the four supporting columns 41 (in which screw threads are cut) by being clamped by nuts. An adjustment is performed by turning these nuts so that the pressing surface of the upper block 42 and the pressing surface of the lower block 43 are oriented parallel to each other.
However, adjustment so that the pressing surface of the upper block 42 and the pressing surface of the lower block 43 maintain a degree of parallel orientation of a few microns is extremely difficult, since actual screws have play and backlash. Furthermore, even assuming that such an adjustment is favorably accomplished, the following problem is encountered: namely, loosening of the screws, etc., in repeated pressing makes it impossible to maintain the degree of parallel orientation, so that re-adjustment must be performed for each operation. For such reasons, the distribution of the load that is applied to the surface of the quartz crystal substrate becomes non-uniform, and this makes it difficult to manufacture a periodic twin structure in a uniform manner.
Furthermore, the surface flatness of conventionally used pressing surfaces is approximately 3 μm, which is more or less the same as the depth of the step working in the surface of the quartz crystal; accordingly, it is difficult to say that the load is uniformly applied.
Moreover, conventionally used pressing surfaces are formed from SUS304; this material tends to soften at high temperatures, and is therefore unsuitable for use in the formation of twins by applying a stress to the surface of the quartz crystal substrate. Furthermore, other problems such as the following problem also occur: namely, traces corresponding to the protruding parts of the step working of the quartz crystal remain in the pressing surfaces after pressing, so that the surface flatness deteriorates. Thus, in conventional pressing apparatuses, there are problems not only in terms of the degree of parallel orientation of the pressing surfaces, but also in terms of the surface flatness and material of the pressing surfaces.
Problems have also been encountered in the pressure control method used in conventional pressing apparatuses. First of all, in the case of control by hydraulic pressure using a hydraulic pressure conversion amplifier, the drawback of a slow response speed is a problem. Specifically, the response time of air pressure is a maximum of 100 ms or less; however, since the rise time of a hydraulic pressure conversion amplifier is long, a time of approximately 1 second is required for the transition from a state in which the load is 0 kN to the maximum load of 10 kN. Furthermore, there is a dead time of 100 ms or longer from the input of the voltage signal to the response of the hydraulic pressure.
Furthermore, in the case of control by hydraulic pressure, the problem of a narrow load setting range arises. In the hydraulic pressure conversion amplifier described above, in cases where a very small air pressure is applied, there is a failure to respond because of the viscosity of the oil. Accordingly, in a system with a maximum load of 10 kN, it is difficult to generate a load of approximately 2 kN or less. Consequently, in cases where the optimal load for twin formation is 2 kN or less, the hydraulic pressure conversion amplifier must be replaced. In such cases, all of the oil in the hydraulic system must be removed and replaced, so that an extremely large amount of work is required; moreover, specialized expertise is required. Furthermore, when the oil is injected following replacement of the hydraulic cylinder, care must be taken to ensure that no air is admixed with the oil, so that considerable time is required. For such reasons, it is extremely difficult to find optimal load conditions for the manufacture of a periodic twin structure in the case of conventional pressing apparatuses.
Furthermore, in a conventional pressing apparatus, as is shown in FIG. 5, both the upper block 42 and lower block 43 each use only one heater 48; consequently, the distance between the heater and the pressing surface varies according to the location on the pressing surface. As a result, a temperature variation with a maximum value of several tens of degrees Celsius is generated in the pressing surfaces, so that the following problem arises: namely, a temperature distribution is produced in the quartz crystal substrate as well, and even if a stress is uniformly applied, there is some irregularity in the manner in which the twin is formed.
Furthermore, in cases where a twin is formed in a quartz crystal using a conventional hot pressing method, the following problem arises: namely, as was described above, the work of forming a step structure on one side of the quartz crystal substrate using photolithographic and wet etching methods must be performed for each quartz crystal substrate.
The present invention was devised in light of the above circumstances; it is an object of the present invention to provide a quartz crystal substrate and a pressing apparatus that make it possible to solve the various problems described above.

National Institute for Materials Science


A sheet for sublimation transfer has an ink layer formed one side of a material sheet. A sublimation transfer ink forming the ink layer contains a binder which does not melt onto a printing medium, such as a printing paper, to which an image is transferred, and will not cause transfer of dyes to the backside of the sheet even when the sheet is rolled and placed in relatively high temperature environment for a long period of time. The binder is composed of vinyl acetal group (X), vinyl alcohol group (Y) ,and vinyl acetate group (Z) as expressed by the following formula (I): ##STR1## wherein R of said polyvinyl acetal resin is C.sub.n H.sub.2n+1, where n is zero or a positive integer greater than or equal to 4.

1. Field of the Invention
The present invention relates to a sheet for sublimation transfer to be used in a thermal transfer recording apparatus, such as a thermal printer, a thermal typewriter, a laser printer and so forth.
2. Description of the Prior Art
In such kind of a sheet for sublimation transfer, a lubricative heat resisting layer is provided on the backside of a material sheet. An ink layer is formed on the surface of the sheet by coating an ink containing dispersing dyes or the like which sublimate by heating. From the backside of the sheet where the lubricative heat resisting layer is formed, thermal transfer corresponding to an image information is performed by means of a thermal head, laser or so forth to transfer the image on to an object, to which the image is to be transferred.
Conventionally, the ink contains a binder in addition to sublimation type dyes. As such binder, in addition to a saturated polyester resin, polycarbonate resin, cellulosic resin, polyvinyl acetoacetal resin (Japanese Patent Laid Open (Kokai) No. 63-151484) and polyvinyl butyral resin (Japanese Patent Laid Open (Kokai) No. 60-101087) among polyvinyl acetal resins are used.
Namely, in the following formula (I) expressing a vinyl acetal group (X), polyvinyl acetoacetal resin contains CH.sub.3 as alkyl group R and polyvinyl butyral resin contains C.sub.3 H.sub.7. ##STR2##
Among the conventional binders saturated polyester resin or polycarbonate resin have relatively high capability of dispersing dyes. However, these resins are defective in a tendency of melting on a printing paper during thermal transfer. On the other hand, polyvinyl acetoacetal resin, polyvinyl butyral resin, or the cellulosic resin, such as ethyl cellulose, propyl cellulose and the like have a property of hardly melting on the printing paper. However, these binder materials have a defect in insufficient holding capability of the dispersing dyes. For instance, the above-mentioned binders are added to respective inks of yellow, magenta, and cyan. Then, respective ink is coated on a material sheet in order of yellow, magenta and cyan to prepare a sheet for sublimation transfer. Then such sheet is wound on a tube of vinyl chloride having a diameter of 1 inch for a plurality of turns, and maintained within a thermostatic chamber at 60.degree. C. for 96 hours. Then, there is observed a dye transferring phenomenon to transfer the dispersing dyes forming yellow, magenta and cyan in the ink layer to the lubricative heat resisting layer on the backside of the material sheet.


A method, apparatus, computer-based product and system employs a digital receiver (or transceiver) to receive, digitize and process a direct sequence spread spectrum signal using efficient, low-cost digital signal processing components. A radio front end portion of the receiver receives and digitizes the signal, and a digital signal processing portion downconverts and despreads the signal by applying a pseudorandom noise (PN) code, used at a transmitter to spread a data signal contained in the direct sequence spread spectrum signal, to the received signal. In order to initially align, and maintain alignment of, the PN code with the direct sequence spread spectrum signal, a timing and state control mechanism is included that provides time reference correction information to the signal processing components of the receiver. This time reference correction information allows the receiver to be compatible with transmitters using inaccurate frequency references which impart a significant frequency ambiguity in the received signal. Additional features include computer-based synchronization methods and mechanisms suitable for use for low performance digital signal processors and employ power management mechanisms that enable long-term operation using battery power. The power management mechanisms enable the receiver to operate in a network setting, over the course of multiple years off battery power, with similar receivers, transmitters and transceiver that communicate with one another using direct sequence spread spectrum signals.

1. Field of the Invention
The present invention is directed to communications-related systems, networks apparatuses and methods as well as computer-based digital signal processing mechanisms and methods used therein. More particularly, the invention is directed to the field of direct sequence spread spectrum (DSSS) communication that employ a DSSS transmitter and a DSSS receiver, or transceiver configured to convey a data signal in a transmitted DSSS signal by spreading the data signal on transmission and correlating on reception so as to "despread" the DSSS signal and recover the data signal.
2. Discussion of the Background
Conventional narrowband (i.e., non-spread spectrum) radio communication devices transmit signals in frequency bandwidths that are roughly equivalent to a data signal bandwidth (or information bandwidth). These devices typically use a radio-frequency (RF) carrier derived from a frequency reference (i.e., a device that produce a precise frequency, although the accuracy of the frequency usually depends on the cost of the device) and modulate the data on the RF carrier. Common conventional data modulation methods such as frequency modulation (FM), phase modulation or amplitude modulation (AM) cause the RF carrier to occupy slightly larger bandwidth then the RF carrier alone, but the total bandwidth for the RF carrier and data is not much larger. As such, interference signals (e.g. jammers) that are transmitted in the same bandwidth as the RF carrier and data can effectively "jam" the signal and prevent a receiver from reproducing the data signal. Aside from jamming, disturbances in the communications path between the transmitter and receiver can interfere with reception. For example, fading due to multipath or atmospheric obstruction can attenuate the signal significantly. Also, shadowing becomes significant if the signal must pass through solid matter such as buildings, walls, floors or trees and vegetation.
Spread spectrum radio communication addresses the shortcomings of narrowband communications by mixing (i.e. applying) a wideband spreading signal to the data signal so as the "spread" the data signal. In these types of systems, the transmitter also modulates a RF carrier with data, as with the narrowband systems, but then adds one more modulation step by modulating the signal with a wideband, noise-like signal (e.g. a PN code). Consequently, the data signal is spread in frequency over a much larger bandwidth, typically several million Hertz (MHZ). Common spread spectrum techniques include frequency hopping and DSSS. Frequency hopping systems move (i.e., "hop") the data modulated carrier to frequencies following a pseudo-random pattern defined by the PN code. DSSS mix a PN code with the data modulated carrier to create a DSSS signal which simultaneously occupies roughly the bandwidth of the pseudo noise signal.
Narrowband interference signals transmitted at same frequency as a portion of the spread signal, "jam" the spread signal by an amount proportional to the ratio of jammer bandwidth to pseudo-noise bandwidth. At a minimum, the interference signal will at least be attenuated by a "processing gain" of the spread spectrum signal, where processing gain is defined as a ratio of data signal bandwidth to spread signal bandwidth. For similar reasons, spread spectrum signals also offer some degree of immunity to channel fading and multipath loss.
DSSS systems have been used in the past to achieve low probability of intercept (LPI) for secure communication and thus are valuable in military applications or other scenarios requiring covert communications. DSSS is also used in places where multipath or fading is prevalent, such as satellite communication. For example, Global Positioning System (GPS) operates using DSSS techniques. However, as recognized by the present inventors, conventional DSSS systems are expensive (considering the transmitter and receiver) because relatively high performance frequency references and digital signal processing equipment is used. Accordingly, DSSS techniques are most commonly used in military and high-end consumer market, where component cost is less of a factor than with low-end consumer product.
Conventional direct sequence spread spectrum transceivers are directed towards high-end systems (e.g. systems costing in the hundreds or thousands of dollars in 1997) that require advanced, if not state-of-the-art, digital signal processing equipment, and associated components. Past DSSS systems have avoided using lower cost components because conventional wisdom dictates that selectively high fidelity frequency references are required at the transmitter and receiver, as well as powerful digital signal processing equipment so to compensate for even minor frequency deviations between transmitter and receiver systems. Contrary to conventional DSSS design practice, the present inventors have identified that these conventional DSSS devices are not applicable for low-end, inexpensive, commercial use applicable for high-volume sale, nor are they well suited for small packages, that may be used in a variety of non-standard field uses, such as, for example, home security and fire systems, data telemetry, access control, remote meter reading as well as other applications.
As recognized by the present inventors, one factor that drives the cost of conventional systems is the use of lengthy PN codes that require substantial digital signal processing to be despread in a receiver. While there are many advantages to using a long code (such as with code division multiple access, CDMA, telephony which permits many users to transmit on a common channel at the same time) the present inventors have recognized that a shorter code, such as a 63 bit PN code, may enable the use of components applicable for lower cost applications.
FIG. 1 is a block diagram of a conventional receive system that of either a conventional receiver (either narrowband or DSSS receiver). The receive system includes a RF front end section 120, a first local oscillator (109, 112, 111, and 110, as will be discussed) section, an analog-to-digital conversion section 121, baseband mixing section (115, as will be discussed) and a baseband processing section 122, as shown. The details of the conventional receiver are described below, following a general overview description. The RF section 120 performs the function of converting electromagnetic wave energy (including the transmitted signal) and outputting an analog signal. The analog signal is maintained within a predetermined signal level range, as controlled by an automatic gain control circuit (AGC) as shown. The output from the RF front end is provided to a first local oscillator section having a mixer 109, which translates the analog signal to a lower frequency by using a precise, and generally expensive, voltage controlled oscillator 110. By employing the precise voltage controlled oscillator 110, the position of the translated signal (i.e., a down converted signal), is controlled to within a narrow predetermined frequency range.
The downconverted signal is then passed to the intermediate frequency processing section 121, that adds appropriate gain prior to a digitalization process while filtering out-of-band images necessary for the digitization process, as will be discussed herein. The output of the intermediate frequency section is passed to the analog to digital converter ADC shown as mixer 115 (as will be discussed), which converts the analog signal into a digital representation for subsequent processing in the baseband section 122.
In this conventional architecture, the analog AGC's function is to keep the signal level applied to the ADC 115 within an operational range of the ADC. Once digitized, the signal is passed to the baseband section 122, where digital signal processing operations are performed on the signal and the signal is detected and demodulated, resulting in outputting the data signal originally transmitted from the transmitter (either in a spread or non-spread form).
In the special case of direct sequence spread spectrum receivers, the burden of performing the "inverse spreading" (despreading) operation on the signal usually falls on the digital signal processor 116 section 1 of the baseband processing section 122. In some cases, the despreading code is mixed in the RF front end 120, first LO or intermediate frequency (IF) sections of the receiver, but such analog architectures require significantly precise components or specialized compensation mechanisms. Accordingly, conventional direct sequence spread spectrum receivers, require high performance digital signal processors or complicated analog sections in order to perform the despreading and correlation functions, as well as signal acquisition and demodulation processes. As a corollary, a precise frequency reference at the DSSS transmitter is assumed to be present so little to no frequency ambiguity is presented into the signal received by the receiver.
Conventional digital receiver design wisdom is such that the loss in performance associated with using low cost, low power desirable and possible components does not justity their use in light of the fact that slightly more expensive components provide greater precision and processing power and therefore avoid performance problems associated with low-cost, inaccurate components. As identified by the present inventors, the high performance digital signal processors, as well as high fidelity voltage controlled oscillators, are not conducive to low cost, low power applications, and that with proper compensation mechanisms, the adverse effects of low cost components can be justified.
More particularly, FIG. 1 depicts RF downconversion and signal conditioning components used to prepare a received analog signal for sampling. Antenna 101 receives the RF signal sent from a transmitter and passes the signal through RF diversity switch 102 and on to a bandpass filter (BPF) 103. Alternatively, a controllable select mechanism 104 may select antenna 105 to receive the RF signal. The antennas may be physically separated and/or of different polarizations so as to enable spatial or polarization diversity reception. The BPF 103 rejects undesired frequencies prior to signal amplification by an amplifier 106. The RF signal is then filtered by BPF 107 and amplified by another amplifier 108 prior to downconversion in a mixer 109. The frequency of the downconversion tone applied to the mixer 109 is controlled by a voltage controlled oscillator (VCO) 110. The output of the VCO 110 is filtered by a BPF 111 and amplified by an amplifier 112.
After downconversion, the downconverted signal is positioned at an intermediate frequency (IF) determined by the downconversion tone applied to the mixer 109, and additional gain is provided by an amplifier 113. A BPF 114 serves as an anti-aliasing filter prior to a second downconversion operation that, as recognized by the present inventors, may be performed with the sampling ADC 115. After the second downconversion operation, the signal is positioned near baseband (i.e. near 0 Hz).
The digital signal processor (DSP) 116 performs various operations including despreading the signal if it is a spread spectrum signal and then sends the baseband signal to a demodulation block 117 so as to extract the data originally added to the transmitted signal by the transmitter. Frequency control of the DSP 116 is provided by an oscillator 118 and using the DSP 116 passes the frequency control to all relevant sections 110, 115 and 117 to compensate for mismatch in received signal frequency, and/or chip phase, though frequency mismatch is usually minimized by using accurate frequency references at the transmitter and receiver. While FIG. 1 depicts a single RF downconversion step, other downconversion steps may be added to properly center the received signal at the desired ADC IF frequency.

Direct sequence spread spectrum method, computer-based product, apparatus and system tolerant to frequency reference offset


A water feeder controller for a boiler monitors a low water cutoff sensor in a boiler and uses a feed timer to feed water to the boiler for a predetermined feed period of time. The feed timer brings the water level in the boiler well above the low water cutoff sensor. The feed timer supplies water to the boiler only if the low water cutoff sensor continues to indicate a low water level for a delay period of time measured by a delay timer. A resettable display indicates the quantity of water supplied by the water feeder to the boiler based on a feed counter incremented during water feeding. A manual feed button allows water to be manually fed to the boiler. The quantity of water manually supplied to the boiler is also shown on the display. The feed timer and delay timer are preferably implemented in software in a microcontroller in the water feeder controller. A lockout loop in the software prevents overfeeding of water to the boiler in the event of a failure of the low water cutoff sensor.

1. Field of the Invention
The present invention relates to devices that automatically supply water to a steam boiler when the water level is low. More specifically, the present invention relates to water feeders for steam boilers of the type used in residential and light commercial heating applications that include a low water cutoff sensor to turn off the burner when the water is below the sensor.
2. Description of Related Art
In conventional boilers of the type used in residential and light commercial heating the water level is monitored with a low water cutoff sensor. When the water level in the boiler drops below the level of the low water cutoff sensor, the burner is turned off until the water level is brought back up to a safe level.
One method of adding water to this type of steam boiler is with an automatic water feeder, which controls a feed valve to supply water to the boiler. When the cutoff sensor senses a low water condition, it stops the burner from firing, and transfers power to the water feeder, allowing it to add make-up water. When the low water cutoff sensor detects that the water level has reached a safe level, it transfers power back to the burner, allowing it to restart and correspondingly disables the water feeder by removing its power.
In conventional water feeder designs of this type, the water feeder is disabled by the low water cutoff sensor as a result of the transfer of power away from the feeder to the burner. Thus the water feeder cannot feed water to the boiler after the burner is re-enabled. One type of low water cutoff sensor uses a float in the boiler, which mechanically drives a switch to transfer power between the burner and the water feeder. In this type of design, the power transfer occurs instantly, as the water level reaches a height sufficient for the float to operate the switch.
Another type low water cutoff sensor uses an electronic probe. With a probe-type electronic sensor, the transfer of power back to the burner can be delayed slightly, allowing a limited amount of additional water to be added above the probe level. However, because the same low water cutoff probe may be used on boilers of various sizes, this delay cannot be too long, as the water feeder cannot be allowed to feed an excess of water into a small boiler.
Water feeders currently available incorporate two timing circuits. The first timer (delay timer) provides for a delay period before the feed valve is activated. This delay allows time for steam within the heating system to condense to water and return to the boiler—thus ensuring that make-up water is required. If the low water cutoff sensor detects that the water level has returned to a safe operating level during the delay period, then no additional water is added and the cutoff sensor re-enables the burner allowing the boiler to operate normally.
The second timer (feed timer) controls the feed valve and adjusts the maximum time that the feeder will supply water to the boiler. After the delay timer has timed out, it triggers the feed timer, which operates the feed valve and begins supplying water to the boiler. When the water in the boiler reaches the low water cutoff sensor, the burner is re-enabled, the feed valve is turned off and the cycle repeats. The feed timer limits the maximum time that water feeding can occur during a feed cycle. Adjustable settings are provided on water feeders to accommodate boilers with different designs and different feed requirements. The best current water feeder designs also include a manual feed override to manually fill the boiler and a lockout feature to prevent the water feeder from cycling/feeding indefinitely in the event of a malfunction of the low water cut-off sensor.
One significant problem with current water feeder designs is that they provide no means for determining how much water has been added to a boiler. Introducing tap water to a boiler too frequently can shorten the life of the boiler. Over time, oxygen rich tap water can rust a cast iron boiler at the water line. Additionally, unwanted and potentially harmful elements, such as lime, can enter the boiler during each feed cycle. If there is a leak in the system, excess deposits can build up in the boiler and produce a layer of material at the bottom of the boiler. This layer typically has poor heat transfer characteristics and can result in the boiler cracking during heating. A water feeder having a display of the amount of water supplied by the water feeder is desirable to allow the owner or installer to determine if the boiler is operating normally, with normal water losses, or if water is leaking from the system, producing rapid water loss.
Another problem with current water feeder designs resides in the fact that the water feeder receives its power from the low water cutoff sensor, which transfers power from the burner to the feeder when the water level is low and removes power from the water feeder as soon as the water level reaches the cutoff sensor. In this type of design the low water cutoff sensor will stop the water feeder during the feed cycle when the level of the water is at or near the level of the cutoff sensor.
Regardless of the duration of the feed timer, the feeder can only fill to approximately the level of the cutoff sensor. While the low water cutoff sensor is installed in the boiler at a safe operating level, it is generally well below the optimum water level for operating the boiler. As a result, boiler operation with a conventional water feeder installed is less efficient than if the boiler were manually filled to operate at a higher water level in accordance with the manufacturer's recommendations.
One solution to this problem has been to use an upper water level sensor to determine when the water feeder has supplied enough water to reach the upper sensor level. The upper sensor is installed above the optimum water level. However, because an upper sensor must be installed at the time the boiler is constructed, and such a sensor increases costs, most boiler manufacturers do not install such a sensor. Consequently, this solution is not suitable for existing boiler installations.
To alleviate this problem installers in the field have made modifications to conventional water feeders by mounting a latching relay near to the water feeder and rewiring the connection between the low water cutoff sensor and the power wiring to the water feeder. The latching relay is installed to supply power to the water feeder after the low water cutoff sensor is satisfied and after the cutoff sensor attempts to remove power from the feeder. This field modification allows the feeder to complete a full feed timer cycle every time and bring the water level above the cutoff sensor. However, field modifications of existing designs are inconvenient at best and require additional installation work. An integrated water feeder design capable of supplying water to above the level of the low water cutoff sensor is desired by the industry.
Bearing in mind the problems and deficiencies of the prior art, it is therefore an object of the present invention to provide a water feeder controller for a boiler having a display for indicating the quantity of water supplied by the water feeder to the boiler.
It is another object of the present invention to provide a water feeder controller for a boiler in which the water feeder raises the water level in the boiler well above the low water cutoff level during the fill cycle and completes an entire predetermined feed cycle during each feed period to add a known quantity of water to the boiler each cycle.
A further object of the invention is to provide a water feeder controller for a boiler that can fill well above the level of the low water cutoff sensor, without requiring a second sensor to detect a water level above the low water cutoff sensor.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.

This patent is subject to a terminal disclaimer.


Disclosed are methods and apparatus for controlling electromagnetic field generation system to generate dynamic magnetic fields. The method can comprise: establishing a dynamic model that describes open-loop dynamics of the electromagnetic field generation system and has an unified state-space form with time delay; configuring a controller based on the dynamic model; applying, by the controller, a control signal to the electromagnetic field generation system; detecting one or more feedback signals from the electromagnetic field generation system; and updating, by the controller, the control signal for controlling the electromagnetic field generation system, according to a reference signal corresponding to a desired dynamic magnetic field, one or more compensated feedback signals, and system states. To address time delay and modeling error and to estimate system states, a Kalman filter and a Smith predictor based compensator can be incorporated.

Recent studies have indicated the potential of using microscale (or nanoscale) robots (referred to collectively as "microrobots") in biomedicine applications, such as drug delivery, targeted therapy, and minimally invasive surgery. Among various techniques for actuating microrobots, magnetic field actuation has many advantages in the context of biomedicine. In particular, magnetic fields are considered harmless to living organisms and have the ability to penetrate deep tissues, allowing signals to be received. For magnetic actuation of microrobots, an electromagnetic coil system (ECS) is used to generate a real-time-controlled dynamic magnetic field. Many types of ECSs with different coils, coil driving modules and control systems have been developed to manipulate microscale and nanoscale devices. In addition, in magnetic particle imaging, ECSs are also used for dynamic imaging magnetic particle tracers.
Magnetic microrobots have various motion principles, and their working frequencies can exceed 100 Hz, making ECS particularly useful for generating dynamic fields for actuation of magnetic microrobots. For example, an ECS can be operated to generate rotating magnetic fields for actuating helical microrobots and nanoparticle swarms, oscillating magnetic fields for actuating micro-robots with elastic tails or with a flexible link, conical magnetic field for actuation of nanowires, square magnetic fields for actuation of resonant magnetic microrobots, and so on. Therefore, the accuracy of dynamic magnetic fields generated by an ECS is essential for high-precision motion control of microrobots and characterization of microrobot behavior.
To control the dynamic magnetic fields in an ECS, the current(s) passing through coil(s) for the ECS need to be regulated. Two types of coil driving modules are typically used to drive electromagnetic coils with dynamically changing currents. One type uses commercially-available servoamplifiers, which can linearly convert an input voltage (representing a command) to an electric current output to the coils. This approach can simplify the driving system, and an open-loop control structure is usually adopted. Another type of coil driving module uses a power inverter-based circuit board to control the dynamic voltage applied on the coil, usually in combination with simple proportional-integral (PI) control. This approach supports higher control frequency, but the relatively complex control implementation adds to development time and cost. In addition, for either type of systems with open-loop control, due to the influence of coil inductance on the dynamics of the coil driving system, the output magnetic field may diverge from the input command when high-frequency magnetic fields are being generated. Therefore, it can be beneficial to introduce closed-loop control (e.g. proportional-integral-derivative (PID) control or model-based control) into ECSs to allow more precise behavioral study and motion control of magnetic microrobots.
However, applying conventional closed-loop control methods to ECSs presents many difficulties. For example, conventional PID controllers are sensitive to system uncertainties (e.g. variation of the coil resistance) and external disturbances (e.g. mutual inductance) because they ignore the system dynamics. Besides, PID control usually has large overshoot and settling time, and magnitudes of PID gains are limited when there is feedback noise. An alternative to PID control is model-based control. However, model-based control of ECSs is challenging since the dynamic model of the servoamplifier and coil cannot be established directly and since different driving system configurations have diverse dynamics, which make it difficult to represent different ECSs using a unified model. Furthermore, the model should consider system time delays and noise in order to avoid large overshoot and system chattering, which makes the optimal control problem even more difficult.

Methods and systems for controlling electromagnetic field generators


A data processing system and method of operation which substantially reduces the time lost in unnecessarily checking for the presence of all memory references required by a special section of code in an operating system before the program is run and which dynamically protect the program requiring the memory reference from crashing if the memory reference is not presently available. The method assumes that all memory references are available and begins running the special section of code. If a request is made for information not in assigned memory storage, the data processing system interrupts the running of the special section of code and undoes everything the special section of code has done prior to the interrupt. The requested memory reference is then located in storage. The information is retrieved and written into assigned memory. The special section of code is then restarted and supplied the needed information.. It has been found that it takes much less time to assume the memory references will succeed and occasionally interrupt, erase and restart, than to make a time-consuming preliminary check for all memory references.

The memory of a computer is frequently divided into pages or page frames. When a program is to be run, it is assigned a certain number of available pages of memory. As the program runs, it makes reference to memory for information, data or subroutines. Some programs or special sections of code, commonly referred to as "subroutines," in a program require that all information, data and subroutines, hereinafter memory references, to be requested be in assigned available memory in order for the special section of code to operate. In the event the special section of code makes such a memory reference, and the reference is not available in the assigned memory, the program undergoes a page fault and an error occurs. In order to avoid this error condition, it is common practice to do a preliminary check to make sure that all required memory references are available to the program before it is run. All of the memory references are then marked or wired into assigned memory so they cannot be erased or moved out of memory before the special section of code is run. The running of this check program requires an extended period of time, much of which is wasted since more often than not all of the requested memory references are available. More time is lost after the program is run in going back through the memory unmarking or unwiring all of the memory references.
It is therefore an object of the present invention to be able to operate a program or special section of code which requires the presence of all memory references in order to avoid a page fault without the time loss involved in running a check program beforehand.
It is also an object of the present invention to provide a data processing system and method of operation which assumes that all memory references to be requested are present, since more often than not they are, and which provides a procedure for taking care of those few instances when the memory reference is not available.

Process for running a computer program subject to interrupt

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FSS 117


An organic electroluminescent device includes an anode, a cathode, and a light emitting zone including a material that at least one of reduces triplet/triplet interaction, reduces triplet/singlet interaction, and reduces singlet/singlet interaction.

1. Field of the Invention
This invention relates to optoelectronic devices, and more particularly, to organic light emitting devices (organic EL devices). More specifically, the present invention relates to substantially stable blue light emitting organic EL devices.
2. Discussion of the Prior Art
An organic electroluminescent (EL) device can be comprised of a layer of an organic luminescent material interposed between an anode, typically comprised of a transparent conductor, such as indium tin oxide, and a cathode, typically a low work function metal such as magnesium, calcium, aluminum, or the alloys thereof with other metals. The EL device functions on the primary principle that under an electric field, positive charges (holes) and negative charges (electrons) are respectively injected from the anode and cathode into the luminescent material and undergo recombination to form excitonic states which subsequently emit light. A number of organic EL devices have been prepared from a laminate of an organic luminescent material and electrodes of opposite polarity, which devices include a single crystal material, such as single crystal anthracene as the luminescent substance as described, for example, in U.S. Pat. No. 3,530,325, the disclosure of which is completely incorporated herein by reference. These types of devices are believed to require excitation voltages on the order of 100 volts or greater.
An organic EL device with a multilayer structure can comprise one organic layer adjacent to the anode supporting hole transport, and another organic layer adjacent to the cathode supporting electron transport and acting as the organic luminescent zone of the device. Examples of these devices are disclosed in U.S. Pat. Nos. 4,356,429; 4,539,507; 4,720,432, and 4,769,292, the disclosures of which are completely incorporated herein by reference. In U.S. Pat. No. 4,769,292, the disclosure of which is completely incorporated herein by reference, an organic EL device comprises three separate layers, a hole transport layer, a luminescent layer, and an electron transport layer, which layers are laminated in sequence and are sandwiched between an anode and a cathode, and wherein a fluorescent dopant material is added to the emission zone or layer whereby the recombination of charges results in the excitation of the fluorescent material. In some of these multilayer structures, such as, for example, organic light emitting devices described in U.S. Pat. No. 4,720,432, the disclosure of which is completely incorporated herein by reference, the organic light emitting device further comprises a buffer layer interposed between the hole transport layer and the anode. The combination of the hole transport layer and the buffer layer forms a dual-layer hole transport region, reference S. A. Van Slyke et al., "Organic Electroluminescent Devices with Improved Stability," Appl. Phys. Lett. 69, pp. 2160-2162, 1996, the disclosure of which is completely incorporated herein by reference.
There have also been attempts to obtain electroluminescence from organic light emitting devices containing mixed layers, for example, layers in which both the hole transport material and the emitting electron transport material are mixed together in one single layer, such as in, for example, Kido et al., "Organic Electroluminescent Devices Based On Molecularly Doped Polymers," Appl. Phys. Lett. 61, pp. 761-763, 1992; S. Naka et al., "Organic Electroluminescent Devices Using a Mixed Single Layer," Jpn. J. Appl. Phys. 33, pp. L1772-L1774, 1994; W. Wen et al., Appl. Phys. Lett. 71, 1302 (1997); and C. Wu et al., "Efficient Organic Electroluminescent Devices Using Single-Layer Doped Polymer Thin Films with Bipolar Carrier Transport Abilities", IEEE Transactions on Electron Devices 44, pp. 1269-1281, 1997. In a number of these devices, the electron transport material and the emitting material can be the same or the mixed layer can further comprise an emitting material as a dopant. Other examples of organic light emitting devices which are formed of a single organic layer comprising a hole transport material and an electron transport material can be found, for example, in U.S. Pat. Nos. 5,853,905; 5,925,980; 6,114,055 and 6,130,001, the disclosures of which are completely incorporated herein by reference.
While recent progress in organic EL research has elevated the potential of organic EL devices for widespread applications, the operational stability of currently available devices may in some instances be below expectations. A number of known organic light emitting devices have relatively short operational lifetimes before their luminance drops to some percentage of its initial value. Providing interface layers as described, for example, in S. A. Van Slyke et al., "Organic Electroluminescent Devices with Improved Stability," Appl. Phys. Lett. 69, pp. 2160-2162, 1996, and doping as described, for example, in Y. Hamada et al., "Influence of the Emission Site on the Running Durability of Organic Electroluminescent Devices", Jpn. J. Appl. Phys. 34, pp. L824-L826, 1995, may perhaps increase the operational lifetime of organic light emitting devices for room temperature operation, however, the effectiveness of these organic light emitting devices deteriorates for high temperature device operation.
Particularly, in order to realize full-color displays, the development of OLEDs emitting in the red, green and blue regions of the visible spectrum is necessary. Although recent advances have led to the development of green and red emitting OLEDs with improved performance in commercial applications, the operational stability of blue-emitting OLEDs is still particularly unsatisfactory.


An improved solution for managing a project. In particular, one or more development artifacts for the project can be annotated based on a collaborative session regarding the development artifact(s). The collaborative session can be stored as a collaborative artifact, which also can be stored in the project. As a result, the collaborative session can be readily recalled and/or subsequently resumed by one or more users.

1. Technical Field
The invention relates generally to annotating a development artifact. Specifically, under the present invention, a development artifact can be annotated with information on one or more collaborative sessions regarding the development artifact.
2. Background Art
Integrated Development Environments (IDEs), such as Websphere® Studio Application Developer offered by International Business Machines (IBM) Corp. of Armonk, N.Y., provide the primary workplace for completing a project, such as the development of a software product. To this extent, a typical IDE provides tools to manage and manipulate several types of development artifacts. For example, in software development, development artifacts can include models, source code files, function libraries, tasks, test cases, activities, etc.
Frequently, multiple individuals contribute to completing any given project. In this case, two or more individuals may collaborate regarding one or more of the development artifacts. For example, two software developers may discuss a particular section of source code. To date, in order to collaborate, individuals must use a collaborative approach that is provided apart from the IDE. Typical collaborative approaches include an in-person conversation, electronic mail, a telephone conversation, a discussion forum, instant messaging (e.g., text chat, voice chat), and the like.
Each of these collaborative approaches has several drawbacks. In particular, each approach requires that the individuals leave the context of the IDE environment. As a result, time is wasted in leaving and returning to the IDE environment, and project information managed by the IDE may not be fully exploited during the collaboration. Further, a record of the collaboration may not be saved and/or may not be readily linked with the development artifact that was discussed. As a result, knowledge that is obtained as a result of the collaboration may be forgotten and/or may not be efficiently disseminated to one or more other individuals contributing to the project.
Within existing IDE environments, several approaches can be used to incorporate some record of the collaboration into the project. For example, an activity tracking system, such as Rational® ClearQuest® offered by IBM Corp., can be used to manage various project-related activities. However, this approach requires an individual to spend additional time in entering a report, and may be overly formal and structured for many collaborations. Further, a textual comment can be added when a development artifact is "checked in" or "checked out" of an artifact management system, such as Rational® ClearCase® offered by IBM Corp. This approach is limited since the comment can only be entered when interacting with the artifact management system, which may occur at a time that is remote from a particular collaboration. Moreover, the collaboration can only be linked to one or more development artifacts, and not to a particular region of an artifact that was discussed during collaboration. Still further, the content of the collaboration can be included in the development artifact itself (e.g., as a comment in source code). However, in addition to being time consuming and occurring apart from the collaboration, this approach may not be desirable when the development artifact is to be provided to customers.
As a result, a need exists for a solution for annotating a development artifact. In particular, a need exists for a method, system and program product that can record a collaborative session between two or more individuals and associate the collaborative session with the corresponding development artifact. To this extent, there exists a need for an IDE that incorporates collaboration functionality, and a project that includes collaboration data that is associated with one or more corresponding development artifacts.

Method, system and program product for annotating a development artifact

International Business Machines Corporation


A hybrid vehicle includes an internal combustion engine, an electric power storage device, an electric motor, a shutter, and an electronic control unit. The shutter is configured to introduce air into an engine compartment of the hybrid vehicle from outside the hybrid vehicle during traveling of the hybrid vehicle in a state where the shutter is open. The electronic control unit is configured to control the internal combustion engine, the electric motor and the shutter. The electronic control unit is configured to control the hybrid vehicle such that starting of the internal combustion engine is more suppressed in a case where the shutter is in a malfunctioning state than in a case where the shutter is not in the malfunctioning state. The malfunctioning state is a state where an opening degree of the shutter does not reach a predetermined opening degree.

1. Field of the Invention
The invention relates to a hybrid vehicle and a control method for the same and, more particularly, to a hybrid vehicle that is provided with a shutter and a control method for the same.
2. Description of Related Art
A shutter, which is disposed in a front grille in the front of a vehicle, is used to adjust the amount of air outside the vehicle which is introduced into the vehicle during the traveling and to adjust the cooling capacity of devices such as the engine in the engine compartment. When the shutter is in a closed state, the amount of the air that is introduced into the vehicle is decreased, and thus air resistance is reduced. When the shutter is in the closed state, a reduction in the temperature of the engine is suppressed while the engine is stopped, and thus the amount of fuel consumption for engine warm-up is reduced. In this manner, fuel economy can be improved by appropriately controlling the opening and closing of the shutter.
In addition, a configuration has been proposed in which the shutter is controlled in accordance with the temperature of the engine so as to ensure that the engine is kept within an appropriate temperature range. For example, Japanese Patent Application Publication No. 2011-98596 discloses a hybrid car in which the shutter is controlled so as to regulate the flow of air between the inside of the engine compartment and the outside of the car when the engine temperature is lower than a predetermined reference temperature.

Hybrid vehicle and control method for the same


A mechanism for predicting whether user interface elements, such as keyboard cues, would be helpful to a computer user and either displaying or hiding the user interface elements based on that prediction is disclosed. Briefly described, an identification is made whether the last input device was a keyboard or a pointing device, such as a mouse. If the last input device was a pointing device, the keyboard cues are hidden. If the last input device was a keyboard, the keyboard cues are displayed. If the input device changes after the keyboard cues have been initially either hidden or displayed, a message so indicating is passed up the window hierarchy. Upon receiving the message, the top-level window responds by causing the display states of all the windows in the window hierarchy to be updated to reflect the changed input device

Many users of computer systems become frustrated with excessive screen clutter. Some users dislike an application window that is cluttered with unnecessary graphics. Dialog box windows especially tend to suffer from this problem. For example, some operating systems provide keyboard cues such as focus indicators and keyboard accelerators. A focus indicator is typically a dashed-line box drawn on the screen within a button or around text that currently has the focus of the window. The focus indicator aids keyboard users identify what function will be activated by depressing the "enter" key on the keyboard. The focus indicator is unnecessary to users that rely heavily on a pointing device, such as a mouse, to input commands to the computer.
Keyboard accelerators are small lines that underline particular letters of words displayed in a control window. Usually, the underlined letter is depressed in combination with a keyboard key, such as the "Alt" key on keyboards commonly used with the Microsoft Windows operating system, to perform a function. Keyboard accelerators allow a user to select a control without having to navigate a pointing device to it. However, the keyboard accelerators are again of little benefit to a heavy mouse user. Moreover, the keyboard accelerators can sometimes confuse the novice keyboard user because the use of the keyboard accelerators is not intuitive. Accordingly, a need exists for a system or method for displaying or not displaying keyboard cues, such as focus indicators and keyboard accelerators, based on whether a user is predominantly a keyboard user or a mouse user.

System, method, and computer-readable medium for displaying keyboard cues in a window


A stand-alone apparatus for determining the level (X) of liquid (F) in oil boreholes (P) overcomes the need of a pressurized gas source. A loudspeaker-type electroacoustical transducer (11) both emits characteristic acoustical signals through the mouth of the borehole and detects the return of an echo from the surface of the liquid downhole for clocking the time-interval between emission and return to determine the level of the liquid. To overcome the limited power inherent in a loudspeaker-type transducer relative to masking borehole acoustic noise, a method of operation correlates the intensity amplitude of the detected echo with the emitted signal. Another solution comprises repeating emission and detection cycles a number of n times and then adding or integrating the n curves into a resulting curve which is filtered. The detected liquid level may be used for determining the submergence and regulating the speed of a pump in the borehole.

The measurement technique by means of reflecting acoustic waves on the surface of the object to be measured is known as echometry. Currently-used equipment for measuring oil levels in production boreholes have a compressed-inert-gas gun which shoots a powerful pressure pulse into the mouth of the borehole and a detector which receives an acoustic signal reflected by discontinuities and singularities in the surfaces reached by the incident acoustic wave. The gas pulse is tipically around between 0.01 and 0.1 seconds. In addition to the reflection on the downhole air-liquid interphase, the detector receives other reflections from joints and other string-surface irregularities which should be discriminated. The detected reflection signal is then processed to determine the time lapsed between the triggering and reception events for determining the target level. The gun requires connection to a gas pressure source, such as a pressurized gas cylinders. These equipments are costly, require transport of equipment and personnel to the well site and are operated just once for each measurement. This moreover implies using portable equipment, specific for obtaining the fluid level in the borehole and qualified personnel for operating such. The well-site operator needs to employ a specialized squad or outsource the job to a firm specialist in echometries.
Due to the operation being costly, the operators need to limit the number of measurements. Tipically, they have to abide with just a few measurements spaced in time because of this, for example just one monthly level measurement during which the level of crude oil in the borehole may vary significantly. Periodically assessing the fluid level is fundamental for increasing the productivity of the borehole.
One such currently known equipment for determining the level of liquid in a pumped borehole is a level detector marketed by the firm Leutert with the trademark Sonoecho. Its main components are a portable data-acquisition unit with a screen, a nitrogen or CO2 gas gun for emitting a pressure pulse through the borehole mouth, a microphone integrated into the body of the gun for receiving the pressure echos reflected back from the string joints and the fluid downhole and transmit them to the portable unit where software processes them for displaying the fluid level on the screen. Although the portable unit can register the logged data and the processing results, or even transmit them to a distant location, a person is needed on site to handle triggering of the pressurized gas shot.
Conventional equipment requires an operator to be there to activate the pressurized gas source.
U.S. Pat. No. 8,902,704 to Rohol discloses a system for logging the fluid level in an oil borehole by emitting pressure waves which are reflected back up by the fluid and the travel time of the acoustic event is measured. Other acoustic systems are disclosed in U.S. Pat. Nos. 3,965,983, 5,285,388, 5,715,890 and 10,087,743. WO publication 2017/106,218 by Schlumberger discloses to a gun for generating an acoustic wave in a borehole.
U.S. Pat. No. 6,237,410 assigned to Tri Ener suggests controlling the speed of a downhole pump according to the height of the liquid in the borehole. By means of an acoustic pulse the level of the liquid is determined and the reflections associated with joints located at known depths in the borehole are used for determining the acoustic propagation velocity in the borehole.

Determining the level of a liquid in a borehole for controlling operation of a submerged pump


An access log analyzer extracts significant information from an enormous amount of data of access logs of a Web server so as to appropriately display the result of analysis. The access log analyzer includes an FTP module for acquiring a log from a server to be analyzed, a pre-formatting module for pre-processing the acquired log, a pre-counting module for totaling preformatted data for each monitored item, a main diagnostic statement creating module for creating a main diagnostic statement for the monitored item of the pre-counted data, a sub-diagnostic statement creating module for creating a sub-diagnostic statement for data related to the main diagnostic statement, a diagnostic statement connecting module for connecting the diagnostic statements, and a dispatcher module for managing the execution of each of the modules. The diagnostic statement creating modules have the functions of calculating a Z value for a diagnosed item and then generating a diagnostic statement in a natural language if there is a variation larger than usual with reference to a diagnostic parameter describing a model of a diagnostic statement corresponding to the range of the Z value.

1. Field of the Invention
The present invention relates to an access log analyzer for analyzing an access log of a server, and in particular, to an access log analyzer for, for example, statistically analyzing an access status of a Web server, which is disclosed on the Internet, so as to be used as a marketing tool for determining the needs of users, for component optimization, and the like.
2. Description of the Related Art
A conventional access log analyzer acquires an access log from a Web server so as to analyze the contents of the acquired access log for totaling the number of hits for each Web page or for each referrer. The number of hits is used to determine the usage of a Web site, for comparison between a number of sites, and the like.
For displaying the results of such analysis, a graph or a table is mainly used. An absolute value is generally represented by a bar chart, whereas a rate is generally represented by a pie chart.
However, since such a conventional access log analyzer basically uses a total number of hits as means of analyzing data, important data may be buried in a large amount of data in some cases.
For example, when the number of hits of the current day is to be evaluated, a change in the number of hits in comparison with the previous number of hits is more important than an absolute value of the number of hits itself. However, since a conventional access log analyzer merely displays an absolute value of the number of hits as a daily change, useful information turns out to be buried in some cases.
Moreover, a difference between the N-th rank and the N+1-th rank is not constant in ranking. Therefore, if the first ranking page is a "clear winner" outdistancing the others, a usual page may rank second in some cases. Furthermore, even if there is a page having a considerably increasing number of hits even though the number is small in absolute number, such a page is buried by a page constantly having a large number of hits.
On the other hand, although the use of a graph or a table is effective to allow easy viewing of a large amount of data as a presentation method, the graph or table merely shows the result of the adding up all of the hits in an easy-to-view manner. Therefore, what the graph or table indicates is required to be read by a user.
In particular, if the number of survey items is increased, the number of graphs or tables is correspondingly increased so as to become enormous. Accordingly, it is difficult to find out useful information from an enormous number of graphs or tables. As a result, the result of analysis is not fully utilized in some cases.
More specifically, assuming that a Web site is evaluated at three steps, from "totaling," "analysis" to "examination for a next strategy," only the first step "totaling" is performed in a conventional access log analyzer. An important "analysis" process is required to be manually done based on an enormous amount of data. As a result, there is a problem that a satisfactory result is not obtained in many cases.

Access log analyzer and access log analyzing method


A feeder assembly for an agricultural harvester, including a first shaft, a second shaft opposite the first shaft, a chain extending around the first shaft and the second shaft, wherein the chain is configured to convey agricultural through the agricultural harvester, and a self-adjusting object deflector assembly positioned between the first shaft and the second shaft, wherein the self-adjusting object deflector assembly comprises a deflector biased against the chain and configured to block the agricultural material from interfering with a connection between the chain and the first shaft.

The invention relates generally to agricultural equipment, such as harvesters, and more specifically, to a self-adjusting object deflector for an agricultural harvester feeder.
A harvester may be used to harvest agricultural crops, such as barley, beans, corn, cotton, flax, oats, rye, soybeans, wheat, grass seed, or other plant seed bearing crops. Moreover, a combine (e.g., combine harvester) is a specific type of harvester generally used to harvest grains (e.g., barley, corn, flax, oats, rye, soybeans, wheat, etc.). Accordingly, a combine may be used to separate a plant into different agricultural materials, such as separating corn ears from the stalks. During operation of a combine, the harvesting process begins by removing a portion of the plant from the ground via a cutting and gathering device (e.g., a header). The combine then moves the plant from the header into the combine with a feeder system. Once inside the combine the plant undergoes processes that separate it into different agricultural materials (e.g., stalks, ears, grain, etc.).
A combine that harvests corn may include, a feeder system that catches and conveys the corn from the header to the combine threshing system using chains and corn engaging slats coupled to the chains. The chains run on gears (e.g., sprockets) that move the chains in a continuous loop. While conveying the corn to the combine, corn cobs may feed into the chain/gear interface, thereby interfering with the connection, e.g., causing the chains to uncouple from the gears or to skip links. A chain that uncouples or skips links may interfere with the material feeding process, and/or induce wear on the feeder components.

Self-adjusting object deflector for an agricultural harvester feeder