A plurality of word lines (WL1) are provided in parallel to one another and a plurality of bit lines (BL1) are provided in parallel to one another, intersecting the word lines (WL1) thereabove. MRAM cells (MC2) are formed at intersections of the word lines and the bit lines therebetween. MRAM cells (MC3) are provided so that an easy axis indicated by the arrow has an angle of 45 degrees with respect to the bit lines and the word lines. Thus, an MRAM capable of cutting the power consumption in writing is achieved and further an MRAM capable of reducing the time required for erasing and writing operations is achieved.

1. Field of the Invention
The present invention relates to a magnetic memory device, and more particularly to a magnetic memory device having a nonvolatile memory cell array which uses a magnetic tunnel junction as each memory cell.
2. Description of the Background Art
<Tunnel Magnetic Resistance Effect>
A structure in which an insulative material is sandwiched between two ferromagnetic materials is termed "magnetic tunnel junction (MTJ)".
FIG. 67 shows a concept of an MTJ. In FIG. 67, an insulating layer TB is provided, being sandwiched between ferromagnetic layers FM21 and FM22 and a voltage is applied to the ferromagnetic layers FM21 and FM22.
In this structure, when a current tunneling the insulating layer TB is measured, it is observed that the measured current value varies depending on the directions of magnetization of the two ferromagnetic layers.
This phenomenon is termed "tunnel magnetic resistance (TMR) effect". The TMR effect will be discussed, referring to FIGS. 68 to 70.
FIG. 68 is a schematic view showing the density of states N(E) of a transition metal. In FIG. 68, the horizontal axis indicates the density of states and the vertical axis indicates an energy E, and electrons included in atoms are grouped according to the directions of spin. Specifically, in FIG. 68, the density of states of atoms having electrons whose direction of spin is downward is shown on the left hand and that of atoms having electrons whose direction of spin is upward is shown on the right hand.
Further, in FIG. 68, since the atoms filled with electrons up to the Fermi level are schematically shown among the 3d orbit and the 4s orbit, the atoms filled with electrons up to the Fermi level are hatched with the Fermi level as the boundary.
The reason why the transition metal becomes a ferromagnetic substance is that the number of electrons whose direction of spin is downward and that of electrons whose direction of spin is upward are different on the 3d orbit among the atoms filled with electrons up to the Fermi level. In other words, since number of electrons whose direction of spin is downward and that of electrons whose direction of spin is upward are equal on the 4s orbit, the electrons on the 4s orbit do not contribute to generation of magnetism.
FIGS. 69 and 70 are schematic views illustrating the TMR effect. In FIG. 69, among the 3d orbit of atoms constituting the ferromagnetic layer FM21 on the left side of the insulating layer TB, the density of states of atoms having the electrons of downward spin is higher than that of atoms having the electrons of upward spin and therefore the direction of magnetization is downward on the whole.
Similarly, the direction of magnetization of the ferromagnetic layer FM22 on the right side of the insulating layer TB is downward on the whole.
Tunneling of electrons mainly occurs so that the directions of spin in an initial state and a final state can be conserved. In the case of FIG. 69, since both the density of states of downward spin in the initial state (inside the ferromagnetic layer FM21) and that in the final state (inside the ferromagnetic layer FM22) are large, the tunneling probability is large and a tunneling current is also large. In other words, the tunnel magnetic resistance is small.
On the other hand, in FIG. 70, since the density of states of upward spin in the initial state (inside the ferromagnetic layer FM21) is large and that in the final state (inside the ferromagnetic layer FM22) is small, the tunneling probability is small and the tunneling current is also small. In other words, the tunnel magnetic resistance is large.
The tunnel magnetic resistance rate (TMRR) is expressed by the following equation;                     TMRR        =                                                            R                AF                            -                              R                F                                                    R              F                                =                                                    P                1                                                          P                2                                                    1              -                                                P                  1                                                                  P                  2                                                                                (        1        )            where the resistance in a case where the directions of magnetization of the two ferromagnetic layers are the same is RF and that in a case where those are opposite is RAF.
Further, in the above Eq. (1), P1 and P2 denotes the spin polarizabilities of the ferromagnetic layers FM21 and FM22, respectively.
Assuming that the density of states of ρ spin band in the Fermi surface is Dρ (EF), the spin polarizability is expressed as;                     P        =                                            D              ↑                              (                                  E                  F                                )                                      -                          D              ↓                              (                                  E                  F                                )                                                                        D              ↑                              (                                  E                  F                                )                                      +                          D              ↓                              (                                  E                  F                                )                                                                        (        2        )
Specifically, the spin polarizability becomes larger as the difference between the density of states of upward spin and that of downward spin is larger. Further, as the spin polarizability approximates 1, the TMRR becomes larger. Furthermore, it is known that the spin polarizability and the magnetization are in proportion to each other. Herein, the spin polarizabilities of various magnetic materials are shown in Table 1:
TABLE 1MaterialsSpin PolarizabilityFe0.44Co0.35Ni0.23Ni80Fe200.25, 0.45FeCo0.53NiMnSb1, 0.58PtMnSb1CrO21Fe3O41(La.Sr)MnO31
A device utilizing the above TMR effect to store data, making correspondence between the directions of magnetization of two ferromagnetic layers and two values, 0 and 1, is an MRAM (Magnetic Random Access Memory).
Accordingly, though it is required to change the direction of magnetization of one of the two ferromagnetic layers in the MTJ, in some cases, the directions of magnetization of both ferromagnetic layers are changed in the structure of FIG. 67 when the magnetic field is given thereto. Then proposed is a structure as shown in FIG. 71, in which an antiferromagnetic layer is formed on the one of the ferromagnetic layers to fix the direction of magnetization of the one of the ferromagnetic layers.
In FIG. 71, the insulating layer TB is sandwiched between the ferromagnetic layers FM21 and FM22 and an antiferromagnetic layer AF is formed above the ferromagnetic layer FM21. Further, a positive electrode of a DC power supply is connected to the antiferromagnetic layer AF and a negative electrode thereof is connected to the ferromagnetic layer FM22.
When a ferromagnetic material and an antiferromagnetic material are formed adjacently to each other, a magnetic flux penetrating these materials is closed to fix the direction of magnetization. This structure is termed "spin valve type ferromagnetic tunnel junction element".
FIG. 72 shows a structure of variation of the spin valve type ferromagnetic tunnel junction element. In FIG. 72, the insulating layer TB is sandwiched between the ferromagnetic layers FM21 and FM22, the antiferromagnetic layer AF is formed above the ferromagnetic layer FM21 and a ferromagnetic layer FM23 is formed below the ferromagnetic layer FM22.
Herein, the antiferromagnetic layer AF is made of, e.g., IrMn containing Ir (iridium) of 20 to 30 atom. %, to fix the direction of magnetization of the ferromagnetic layer FM21, and the ferromagnetic layer FM21 is made of CoFe having large coercivity because it is better that the direction of magnetization should be hard to reverse with respect to the external magnetic field.
Further, as discussed earlier referring to Eq. (1), since the tunnel magnetic resistance rate (TMRR) becomes larger as the spin polarizability is larger, CoFe is used as a material having large spin polarizability.
On the other hand, though the ferromagnetic layer FM22 is also made of CoFe, it is desirable that the ferromagnetic layer FM22 should be made of a material having small coercivity so that its direction of magnetization may be controlled by a smaller external magnetic field.
In the structure of FIG. 72, Ni80Fe20 (permalloy) having small coercivity and small spin polarizability is used as the ferromagnetic layer FM23 to allow easy reverse in the direction of magnetization of the ferromagnetic layer FM22. The direction of magnetization of the ferromagnetic layer FM22 can be thereby reversed by a small external magnetic field.
FIG. 73 shows a practical structure of the spin valve type ferromagnetic tunnel junction element of FIG. 72, and FIG. 74 shows measured characteristics of TMR in this structure.
In FIG. 73, the insulating layer TB is formed above a layered structure consisting of the antiferromagnetic layer AF and the ferromagnetic layer FM21 which are formed two-dimensionally on a substrate BD, and the ferromagnetic layer FM23 is formed above the insulating layer TB. A measured result of change in magnetic resistance MR at the time when the external magnetic field is given to such a structure is shown in FIG. 74.
In FIG. 74, the horizontal axis indicates the magnetic field (converted by 1 oersted=about 79 A/m) and the vertical axis indicates the tunnel magnetic resistance rate (TMRR). It can be seen from FIG. 74 that the TMRR is 36%, the magnetic field required to reverse the direction of magnetization is low, i.e., about 30 (×79 A/m), and a hysteresis symmetric with respect to the direction of magnetization is achieved.
<Structure and Operation Principles of MRAM>
In the MRAM, the directions of magnetization of the two ferromagnetic materials in the magnetic tunnel junction element making up a memory cell are controlled to be the same or opposite by the external magnetic field and the state where the directions of magnetization are the same or the state where the directions of magnetization are opposite is brought into correspondence with 0 or 1, to store data.
The stored data can be read out by passing a predetermined current through the memory cell and sensing the voltages at both ends of the tunnel magnetic resistance. Since sensing becomes easier as the tunnel magnetic resistance rate (TMMR) is larger, a ferromagnetic material having large spin polarizability is advantageous to the MRAM.
Further, in order to write data, it is only necessary to change the direction of magnetization of one of the ferromagnetic materials by using the magnetic field generated by passing a predetermined current through the lines (word line and bit line).
<Structure of MRAM Cell>
Now, discussion will be made below on a structure and an operation of an MRAM disclosed in U.S. Pat. No. 5,793,697 as a background-art example.
FIG. 75 is a perspective view showing an MRAM cell array and cells. In FIG. 75, word lines 1, 2 and 3 are provided in parallel to one another and bit lines 4, 5 and 6 are provided in parallel to one another, intersecting the word lines thereabove.
MRAM cells (hereinafter, sometimes referred to simply as "cell") 9 are formed at intersections of the word lines and the bit lines therebetween. In FIG. 75, as shown in an enlarged view, the MRAM cell 9 has a structure in which a silicon pn-junction diode 7 and a magnetic tunnel junction element (MTJ) 8 are layered on the word lines.
FIG. 76 is a schematic view showing a cross-sectional structure of the MRAM cell 9. Further, FIG. 76 shows the MRAM cell 9 on the word line 3, where the word line 3 is provided on a silicon substrate 80 and thereon an n+ silicon layer 10 and a p+ silicon layer 11 are layered to make up the pn-junction diode 7. The pn-junction diode 7 is covered with an insulating film such as a silicon oxide film 13.
A tungsten stud 12 is formed above the pn-junction diode 7 and the pn-junction diode 7 is electrically connected to the MTJ 8 through the tungsten stud 12. Further, the silicon oxide film 13 is so provided as to also cover the tungsten stud 12 and surfaces of the tungsten stud 12 and the silicon oxide film 13 are planarized by CMP (Chemical Mechanical Polishing).
MTJ 8 has a layered structure consisting of a template layer 15 (having a film thickness of 10 nm) made of platinum (Pt), an initial ferromagnetic layer 16 (having a film thickness of 4 nm) made of permalloy of Ni81Fe19, a diamagnetic layer 18 (having a film thickness of 10 nm) made of Mn54Fe46, a ferromagnetic layer 20 (having a film thickness of 8 nm) made of permalloy of CoFe or Ni81Fe19 and having a fixed direction of magnetization, a tunnel barrier layer 22 made of Al2O3, a soft ferromagnetic layer 24 made of a multilayer film consisting of CoFe having a film thickness of 2 nm and Ni81Fe19 having a film thickness of 20 nm, and a contact layer 25 made of Pt from the bottom.
Further, the tunnel barrier layer 22 is formed by depositing Al having a film thickness of 1 to 2 nm and performing the plasma oxidation method for 60 to 240 seconds with the power density of 25 W/cm2 under the oxygen pressure of 100 mTorr (100×10−3×1.33×102 Pa).
Furthermore, not shown in FIG. 76, a large MTJ is actually formed entirely over a surface of the silicon oxide film 13 on the substrate 80 and the MTJ is patterned by argon ion milling with a photoresist mask, to form a plurality of small MTJs 8 as shown in FIG. 76. Each MTJ 8 is covered with a silicon oxide film 26. Further, not shown in FIG. 76, the contact layer 25 is connected to the bit lines.
The magnetic tunnel resistance of the MTJ 8 varies depending on whether the direction of magnetization of the soft ferromagnetic layer 24 discussed above is the same as that of the ferromagnetic layer 20 or opposite to. The direction of magnetization of the soft ferromagnetic layer 24 can be changed by a magnetic field generated by a current flowing the bit lines and the word lines.
Further, the magnetic tunnel resistance of the MTJ 8 greatly depends on the film thickness and the barrier height of the tunnel barrier layer 22 and the material characteristics of a film, such as roughness, at an interface below the junction.
The soft ferromagnetic layer 24 is so formed as to have an easy axis which is a direction of easy magnetization. There are two directions of magnetization along the easy axis, corresponding to two data of the memory cell, 0 and 1, respectively.
On the other hand, the ferromagnetic layer 20 is formed so that its direction of magnetization should be the same as the easy axis of the soft ferromagnetic layer 24 and the direction should not be changed depending on the operating state of the MRAM.
Such a direction of magnetization is termed "unidirectional anisotropy direction". The easy axis of the soft ferromagnetic layer 24 is defined by a combination of the intrinsic anisotropy, the stress induced anisotropy and an anisotropy which depends on shape of the MTJ 8.
The intrinsic anisotropy refers to an anisotropy of magnetization intrinsic to a ferromagnetic substance, and the stress induced anisotropy refers to an anisotropy of magnetization generated at the time when a stress is applied to a ferromagnetic substance.
Further, as shown in FIG. 75, the MTJ 8 has a rectangular shape with a long side L and a short side W in a plan view. This is because the easy axis of the soft ferromagnetic layer 24 is defined by using the anisotropy which depends on the shape of the MTJ 8.
Next discussion will be made on a method of setting the unidirectional anisotropy direction of the ferromagnetic layer 20. The initial ferromagnetic layer 16 deposited on the template layer 15 grows with a surface ({111} surface) whose crystal orientation is a {111} orientation upward. Further, the diamagnetic layer 18 made of MnFe is deposited on the initial ferromagnetic layer 16.
These magnetic layers are deposited under the magnetic field whose direction is the same as that of the easy axis of the soft ferromagnetic layer 24 which is deposited later, and the unidirectional anisotropy direction of the soft ferromagnetic layer 24 is thereby defined.
Further, since the magnetic flux is closed between the ferromagnetic layer 20 and the diamagnetic layer 18, the direction of magnetization of the ferromagnetic layer 20 becomes harder to change by the external magnetic field than that of the soft ferromagnetic layer 24, and the direction of magnetization of the ferromagnetic layer 20 is fixed within a range of magnitude of the magnetic field generated by the current flowing the word lines and the bit lines. Moreover, since the MTJ 8 has a rectangular shape in a plan view, a magnetizing anisotropy which depends on the shape of the ferromagnetic layer 20 is generated, which contributes to the stabilization in the direction of magnetization of the ferromagnetic layer 20.
<Outline of Writing/Reading Operation of MRAM>
Discussion will be made below on writing/reading operation of the MRAM.
When a predetermined current is passed through a word line and a bit line for address selection (referred to as "selected word line" and "selected bit line"), magnetic fields are generated around the lines and a coupled magnetic field obtained by coupling these magnetic fields is generated at an intersection (selected address) of these lines. When this magnetic field is given, the direction of magnetization of the soft ferromagnetic layer 24 in the MTJ 8 provided at the intersection of these lines is rotated in a surface of the layer, to write data.
The magnitude of the magnetic field is so designed as to be larger than that of a switching magnetic field (the magnetic field at which the direction of magnetization starts rotating) of the soft ferromagnetic layer 24, which mainly depends on the coercivity and the magnetizing anisotropy of the soft ferromagnetic layer 24.
Further, the magnetic fields generated around the selected word line and the selected bit line must be designed enough small to avoid rotation of the unidirectional anisotropy direction of the ferromagnetic layer 20. This is intended not to change the direction of magnetization of a half-selected cell. The half-selected cell refers to a cell in which the current flows in only one of the word line and the bit line which are provided thereabove and therebelow.
Thus, the architecture of the memory cell array is so designed as to avoid direct flow of the writing current into the MTJ 8, for the purpose of cutting the power consumption in data writing.
Further, the data written into the MRAM cell 9 are read out by sensing the current flowing vertically through the pn-junction diode 7 and the MTJ 8. Furthermore, since a tunneling current flows vertically through the MRAM cell 9 during operation, the occupied area of the MRAM cell 9 can be reduced.
The resistance of the tunnel barrier layer 22 made of Al2O3 in the MTJ 8 varies almost exponentially with respect to the film thickness thereof. Specifically, the current flowing in the tunnel barrier is reduced as the film thickness becomes thicker and only a current tunneling the junction flows vertically with respect to the junction.
The data in the MRAM cell 9 are read out by monitoring a voltage of the MRAM cell 9 generated when a sense current too much smaller than the writing current flows vertically in the MTJ 8.
As discussed earlier, the tunneling probability of the MTJ 8 increases as the density of states of the spin having the same polarity as the spin in the soft ferromagnetic layer 24 in the initial state is higher in the ferromagnetic layer 20 in the final state.
Accordingly, the magnetic tunnel resistance of the MTJ 8 is low when the states of spin of the soft ferromagnetic layer 24 and the ferromagnetic layer 20 are the same, in other words, the directions of magnetization of these layers are the same and is high when the directions of magnetization of these layers are opposite. Therefore, the data in the MRAM cell 9 can be read out only by monitoring the resistance of the MTJ with a microcurrent.
Further, the magnetic field generated by the sense current is negligible, which has no effect on the state of magnetization of the MRAM cell 9. Furthermore, since lines required for the reading/writing operation of the MRAM cell 9 are only the bit lines and the word lines shown in FIG. 75, an efficient memory cell array can be achieved.
<Writing Operation>
Further discussion will be made below on the writing operation of the MRAM, referring to FIGS. 77 and 78.
FIG. 77 is an equivalent circuit diagram of the MRAM cell array of FIG. 75, where both ends of the word lines 1 to 3 are connected to a word-line control circuit 53 and both ends of the bit lines 4 to 6 are connected to a bit-line control circuit 51. Further, for convenience of illustration in FIG. 78, the word lines 1 to 3 are represented as word lines WL1 to WL3 and the bit lines 4 to 6 are represented as bit lines BL4 to BL6 in some cases.
At the intersections of the word lines 1 to 3 and the bit lines 4 to 6 provided are the MTJs 8 represented by resistance symbols and the pn-junction diodes 7 represented by diode symbols.
Herein, assuming that the word line 1 and the bit line 4 are selected, an MRAM cell 9a located at the intersection of these lines is selected.
Writing to the selected MRAM cell 9a is performed by the coupled magnetic field generated by a current IB flowing in the bit line 4 and a current IW flowing in the word line 1.
A magnetic field generated by either one of the current IB and the current IW in the cell region is smaller than that required to change the direction of magnetization of the soft ferromagnetic layer 24 in the MTJ 8.
Therefore, in the MRAM cell arrays 9b to 9e which are half-selected cells (cells in which only one of the current IB and the current IW flows in the bit lines or the word lines), no writing operation is performed.
When the magnetic fields generated by the current IB and the current IW are coupled, however, the magnitude of the coupled magnetic field becomes enough large to change the direction of magnetization of the soft ferromagnetic layer 24 in the selected memory cell 9a.
Further, at least one of the current IB and the current IW is so designed as to flow bidirectionally in order to allow the direction of magnetization of the soft ferromagnetic layer 24 in the cell 9a to be two opposite ones. Furthermore, in FIG. 77, since two bit-line control circuits 51 and two word-line control circuits 53 are provided in pairs, both the currents IB and IW can change the directions of current flow.
FIG. 78 is a timing chart showing voltages and currents of the bit lines 4 to 6 (bit lines BL4 to BL6) and the word lines 1 to 3 (word lines WL1 to WL3).
As shown in FIG. 78, the voltages of the bit lines BL4 to BL6 in writing are set to a voltage Vb which is suitable for bidirectional currents. The voltages of the word lines WL1 to WL3 are set to a voltage Vw which is larger than the voltage Vb and positive.
On standby, these voltages are so set as to apply a reverse bias to the pn-junction diodes 7 in all the cells 9. Accordingly, neither the current IB nor the current IW flows in the memory cells on standby.
<Reading Operation>
Next discussion will be made on a reading operation of the MRAM in more detail, referring to FIGS. 77 and 78. As shown in FIG. 78, the voltage of the word line WL1 is lowered from Vw to Vb and the voltage of the bit line BL4 is raised from Vb to Vw, to apply a forward bias to the pn-junction diode 7 in the selected cell 9a
In reading, the voltages of non-selected bit lines 5 and 6 are still the standby voltage Vb and those of the non-selected word lines 2 and 3 are still the standby voltage Vw.
Further, since there is no voltage drop from the word lines to the bit lines (in other words, 0 V is applied to the pn-junction diodes 7) in the half-selected cells 9b to 9e, no current flows in the cells.
The magnitude of a sense current 30 (see FIG. 77) flowing through the bit line BL4 and the cell 9a into the word line WL1 depends on the magnetic tunnel resistance of the selected cell 9a In a sense circuit which is a constituent element of the bit-line control circuit 51, assuming that an average value of two current values estimated correspondingly to two states of the cell is defined as a reference current, the sense current is compared with the reference current. Then, the difference between the sense current and the reference current is amplified, to read data stored in the selected cell 9a.
Further, as shown by the waveform of the sense current 30 in FIG. 77, the sense current 30 has two kinds of current waveforms corresponding to two magnetic states of the MTJ 8.
After reading data, the voltages of the bit line BL4 and the word line WL1 are returned to the respective standby voltages, but the magnetic state of the memory cell 9a remains after the reading operation.
As discussed above, in writing data into the MRAM cell, the magnetic fields are generated by passing a current through the bit line and the word line. Since a magnetic field larger than the switching magnetic field of the soft ferromagnetic layer which is a constituent element of the cell has to be applied to the memory cell at the selected address, a relative large current is needed to flow. For this reason, the power consumption in writing disadvantageously becomes large.
Further, the background-art MRAM cell array has a problem that it takes long period of time to perform a batch erasing or a batch writing of data in a unit of memory block constituted of at least one memory cell array.

Magnetic memory device capable of passing bidirectional currents through the bit lines


A collapsible working chair including a flat base equipped with swivel wheels for moving on the ground, the flat base having a recessed top side divided by a partition plate into a front open chamber for keeping tools and tool accessories, and a rear open chamber for receiving a seat, and two pairs of mounts symmetrically fixedly mounted in the rear open chamber; a seat supported on the flat base; and two pairs of folding collapsible supports connected between the mounts of the flat base and the seat, and set between the working position to support the seat above the flat base and the collapsed position to receive the seat within the rear open chamber of the flat base.

1. Field of the Invention
This invention relates to working chairs, and relates more particularly to a collapsible working chair which has a tool chamber for keeping hand tools and tool accessories and, which can be collapsed when not in use.
2. Description of the Prior Art
Regular tool cases are simply designed for carrying hand tools and tool accessories. If a tool case holds a variety of hand tools and tool accessories, it becomes heavy, and not easy to move in the working area by hand. Furthermore, regular working chairs are commonly made of fixed type, and the legs thereof cannot be moved on the ground.

Collapsible working chair with a tool storage chamber


A system and method for switching digital circuit clock net driver without losing clock pulses is presented. A device uses glitchless clock selection logic, which includes an edge detector, to select a clock signal to provide to device circuitry based upon the device circuitry's performance requirements. When the rising edges of a first clock signal and a second clock signal align, the edge detector momentarily pulses a clock switch signal, which is used to clock in a clock selection signal to a multiplexer. As a result, when the clock selection signal is high, the device waits until the clock edges are aligned before switching clock signals.

1. Technical Field
The present invention relates to a design structure for switching a digital circuit clock net driver without losing clock pulses. More particularly, the present invention relates to a design structure for detecting clock edge alignments in order to select a clock signal from a plurality of clock signals without introducing clock cycle dead time.
2. Description of the Related Art
As technology advancements push digital circuit operating frequencies higher, an increase in power consumption and thus, heat generation, have grown to significant levels. Aggressive processor designs today use higher operating frequencies in order to deliver increased performance. A challenge found with these processor designs, however, is that they require a substantial amount of power and generate a substantial amount of heat. As a result, these designs face problems such as reduced battery life as well as undesirable noise levels from fans that are required to ventilate the processor.
One solution to reduce power consumption is to design a high-speed processor with the ability to control its own clock frequency and supply voltage. This is known as "dynamic voltage scaling," or DVS, a technique that varies the supply voltage and clock frequency based on processor computation load. By this approach, during intervals when the processor demands are low, both frequency and voltage are scaled down. Conversely, during intensive processor computations, frequency and voltage are switched to a maximum level.
One approach to switching clock frequencies is to have multiple clock drivers running at different frequencies that are selected through a glitchless multiplexer. The different clock drivers are driven from the same source phase-locked loop (PLL) where the varying frequencies are achieved by ratioed frequency dividers. It is even possible to have programmable dividers that provide a range of operating frequencies. A challenge found, however, is that changing the frequencies on these dividers can introduce glitches on the clock multiplexer output.
Existing art may use a multiplexer (mux) to prevent clock glitches from reaching device circuitry. The glitchless multiplexer selects between multiple input clock sources and transitions between sources glitchlessly. A challenge found with current glitchless multiplexer designs, however, is that they ensure glitchless operation by removing clock pulses and holding the clock net output stable for an extended period of time before the multiplexer outputs the new clock.
While this may prevent glitches, this solution creates clock cycle "dead time" that presents problems in other areas, such as with dynamic circuits expecting a certain clock period. For example, the state of a given circuit depends on a capacitive charge. If the clock period is too long, the dynamic circuit's capacitive charge is not refreshed and thus, state is lost due to leakage current. As such, when a glitchless multiplexer changes operating frequency, dynamic circuits may be adversely affected by its "dead time."
Existing art attempts to alleviate this issue by using a reference clock to indicate when to change clock signals. The reference clock, however, operates at a lowest common multiple of the clock signals from which are selected. A challenge found with this approach is that possible combinations of clock ratios that may be switched are limited by the frequency of the lowest common multiple clock.
What is needed, therefore, is a system and method that provides clock switching ratio flexibility to dynamically switch clock signals without introducing clock cycle dead time into a device's circuitry.

This patent is subject to a terminal disclaimer.

Design Structure for switching digital circuit clock net driver without losing clock pulses

International Business Machines Corporation


In one embodiment, an annular groove and an elastic portion are formed at an end portion of a main bearing on a side facing a cylinder chamber. An annular groove and an elastic portion is formed at an end portion of the sub-bearing on a side facing the cylinder chamber. A depth of the annular groove of the main bearing is formed larger than that of the sub-bearing. An outer peripheral surface of the elastic portion of the main bearing is formed in a straight shape so that thicknesses of a base portion and a tip portion of the elastic portion are the same. An outer peripheral surface of the elastic portion of the sub-bearing is formed in a tapered shape so that a thicknesses of a base portion of the elastic portion is larger than that of a tip portion of the elastic portion.

A rotary compressor for compressing a gas refrigerant which houses an electric motor and a compression mechanism portion respectively connected with each other via a rotary shaft is disclosed in the Japanese Patent Publication No. 5263360. A refrigerating cycle device which cools and heats air by circulating the gas refrigerant compressed by the rotary compressor through a radiator, an expansion device and a heat-sink is also disclosed in the Patent Publication.
In such a rotary compressor, a rotary shaft is supported rotatably by a main bearing and a sub-bearing which are a pair of bearings. In order to suppress increase of contact pressure between the rotary shaft and the bearings and attrition of the rotary shaft and the bearings, an annular groove and an elastic portion located inside the annular groove are formed in each bearing.
In the rotary compressor, the annular groove provided in the main bearing is formed in a shape of a straight i.e. in a shape of a cylinder so that the width dimension of a bottom portion and the width dimension of a tip portion are the same. The outer peripheral surface of the elastic portion provided in the main bearing is also formed in a shape of a straight so that the width dimension of a base portion and the width dimension of a tip portion are the same. On the other hand, the annular groove provided in the sub-bearing is formed so that the width dimension of a bottom is smaller than the width dimension of a tip portion. The outer peripheral surface of the elastic portion provided in the sub-bearing is formed in a tapered shape so that the width dimension of a base portion is larger than the width dimension of a tip portion. Further, the depth dimension of the annular groove provided in the sub-bearing is formed so that the annular groove of the sub-bearing is larger than the depth dimension of the annular groove formed in the main bearing.
In such a rotary compressor, attrition of an elastic portion of a main bearing and a rotary shaft within a contact range is desired to decrease so that reliability is enhanced.

Rotary compressor and refrigerating cycle device having bearings containing annular groove/elastic portion arrangement


Hexanitrobenzene is prepared by oxidizing the amine group of pentanitroaniline with H.sub.2 O.sub.2 in H.sub.2 SO.sub.4. The compound is a high density explosive.

1. Field of the Invention
This invention relates to methods for preparing aryl compounds having a multiplicity of nitro groups attached. More specifically, this invention relates to a method for the preparation of hexanitrobenzene.
2. Description of the Prior Art
Hexanitrobenzene is of great interest to those concerned with explosives. Aryl compounds with large numbers of nitro groups on the rings are well known to be explosives. A typical example is trinitrotoluene which is more commonly known simply as TNT. Orlova reports a method for preparing hexanitrobenzene in "Chemistry and Technology of High Energy Explosive Substances," Khimia (1973). However, the authors of this specification were unable to duplicate the results of the Russian author. Accordingly, the authors of this specification, after a considerable amount of experimentation, developed the hereinafter disclosed method for the preparation of hexanitrobenzene.

The United States of America as represented by the Secretary of the Navy


Techniques for automatic creation of media collages are described. In one or more implementations, unwanted frames are identified and removed from items of media content. A media score is then determined for items of media content based on characteristics of an appearance of the items within a plurality of collage templates. A template score is determined for each collage template of the plurality of collage templates by combining the media scores for each media item of the plurality of media items included in a collage template. At least one of the plurality of collage templates is selected based on determined template scores. Then, at least one media collage is outputted based on the selected collage templates.

Cameras are becoming increasingly accessible and commonplace, allowing users to capture media content of aspects of everyday life. After capturing media content, such as videos, digital images, and so forth, users have numerous options for displaying this content. However, many of these options require a significant amount of a user's time in order to create aesthetically pleasing presentations of the user's media content for display. For example, it may take several iterations to select a digital image that fits within an atypically-shaped frame without obfuscating some feature in the image that the user feels is important.
In another example, with the current techniques, a user is subject to several steps to manually create a media collage containing video. First, the user must select from among items of media content that is accessible to the user, and must select from available collage templates to display the media collage. Both the number of items of media content and the number of collage templates can be in the dozens, hundreds, or even thousands of options. Once the user has selected an item of media content and a collage template, the user then fits the selected item of media content into a cell of the collage template. The user then previews the media collage at this stage to determine whether the video content clips outside of its cell, whether the video has been placed in the desired cell of the collage template, whether the video contains black (or unwanted, uniform color) frames, whether a pause frame of the video contains a desired image, and whether the video has a sufficient amount of interesting content, to name some examples. For each item of media content added to the media collage, the fitting to the cell and previewing must be repeated, which is both time-consuming and frustrating for users.


Methods and systems for processing an RF signal are disclosed herein. Aspects of the method may comprise utilizing a single input CORDIC and a single output CORDIC for synchronizing and demodulating a received signal, wherein the received signal may comprise one or more bit rates. The received signal may comprise a one megabit per second (Mbps) signal. The single input CORDIC may be configured to operate in a rotating mode and the single output CORDIC may be configured to operate in a rotating mode and/or an arctangent (ARCTAN) mode. A rotated output of the single input CORDIC may be correlated with a phase shift keying (PSK) synchronization (sync) word and a portion of the correlated rotated output of the single input CORDIC may be buffered.

Communication systems are known to support wireless and wired communications between wireless and/or wired communication devices. Such communication systems range from national and/or international cellular telephone systems to the Internet to point-to-point in-home wireless networks. Each type of communication system is constructed, and hence operates, in accordance with one or more communication standards. For instance, wireless communication systems may operate in accordance with one or more standards including, but not limited to, IEEE 802.11, Bluetooth, advanced mobile phone services (AMPS), digital AMPS, global system for mobile communications (GSM), code division multiple access (CDMA), local multi-point distribution systems (LMDS), multi-channel-multi-point distribution systems (MMDS), and/or variations thereof.
Depending on the type of wireless communication system, a wireless communication device, such as a cellular telephone, two-way radio, personal digital assistant (PDA), personal computer (PC), laptop computer, and/or home entertainment equipment, communicates directly or indirectly with other wireless communication devices. For direct communications, also known as point-to-point communications, the participating wireless communication devices tune their receivers and transmitters to the same channel, or channels, such as one or more of the plurality of radio frequency (RF) carriers of the wireless communication system, and communicate over that channel(s). For indirect wireless communications, each wireless communication device communicates directly with an associated base station for use of cellular services, for example, and/or an associated access point for use of an in-home or in-building wireless network, for example, via an assigned channel, or channels. To complete a communication connection between the wireless communication devices, the associated base stations and/or associated access points communicate with each other directly, via a system controller, via the public switch telephone network, via the internet, and/or via some other wide area network.
For each wireless communication device to participate in wireless communications, it may include a built-in radio transceiver comprising a receiver and transmitter, or it may be coupled to an associated radio transceiver, such as a station for in-home and/or in-building wireless communication networks, and/or an RF modem. The transmitter may be adapted to convert data into RF signals by modulating the data in accordance with the particular wireless communication standard to produce baseband signals and mixes the baseband signal with a local oscillator signal in one or more intermediate frequency stages to produce the RF signals. The radio receiver may include an antenna section, a filtering section, a low noise amplifier, an intermediate frequency (IF) stage, an equalization stage, and/or a demodulator. The antenna section may receive RF signals and may provide them to the filtering section, which, in turn, may pass RF signals of interest to the low noise amplifier (LNA).
The LNA may amplify the received RF signals of interest and may provide them as amplified RF signals to the IF stage. The IF stage may step down the frequency of the RF signals of interest to an intermediate frequency or to baseband. The IF stage may then provide the intermediate frequency signals, or baseband signals, to the equalization stage. The equalization stage may add loss or delay to specific frequencies to produce a flat frequency response. The equalization stage may then output an in-phase (I) and/or a quadrature (Q) component to the demodulator. The demodulator may be adapted to synchronize the signal and/or to recapture the data in accordance with a demodulation protocol.
In conventional RF transceivers, for the demodulator to accurately recover data from IF signals or baseband signals, DC offsets may need to be overcome. DC offsets in a demodulated output may result when the clock circuitry of a transmitting radio produces a slightly different clock rate than the clock rate produced by the receiving radio. The local oscillation within the transmitting radio, therefore, may not produce the exact same rate of oscillation as the rate produced by the local oscillation in the receiving radio. In addition, the RF transceiver may need to account for a phase offset during demodulation, time error detection, vector-to-angle conversion, vector-to-amplitude conversion, and/or vector rotation, for example. The conventional RF transceiver, therefore, may need to utilize a plurality of separate circuits, such as a DC offset compensation circuit, a phase offset compensation circuit, and other circuitry necessary for signal synchronization and/or demodulation. Consequently, a large number of circuits may be required for implementing a conventional RF transceiver, which may increase production costs and decrease efficiency. Additionally, a large number of circuits require a much larger silicon and increases power consumption.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.

Method and system for reuse of CORDIC in an RF transceiver by reconfiguration in real time


An athletic support device in the nature of a brace for use in bowling, having a casing that extends along a portion of the hand and/or wrist, means for coupling the casing to the hand, at least one inflatable bladder associated with the casing located at the position or positions where support is desired, and means for providing gas to the inflatable bladder so that the bladder may be inflated to provide support to the hand and/or wrist, as desired. The device includes means for deflating the bladder or bladders, so that the level of support provided may be adjusted to a desired level. The bladders may be incorporated into conventional support device designs, such as gloves, braces, and wraps. Preferably, bladders are associated with the casing at one or more of the following areas: palm area, wrist area, or finger area. In this way, the device may be tailored to the bowler's hand or to provide an optimal position of the hand and/or wrist for a desired delivery of the ball.

Athletic support devices are frequently used by bowlers for added comfort or control of the ball. Such devices may control the delivery of the ball by controlling, for example, the manner in which the ball is cradled in the bowler's hand, or the manner in which the ball is released. Further, these devices may provide support to the hand and/or wrist to control the movement of the hand, wrist, and forearm to prevent movements such as "breaking."
A number of styles of support devices exist, which provide various desirable features, including gloves, splints, and wraps, which may likewise incorporate rigid splints. Gloves, for example, may include "tacky fingers" that have a higher coefficient of friction and provide the bowler with added control of the ball at release. Gloves may also provide added comfort to the bowler.
Splint-type devices and wraps that include rigid splints are generally used to limit the movement of the hand, wrist, and forearm. Splints are generally strapped to the hand and wrist, while wraps are generally wrapped around the wrist and/or hand and secured by straps, adherent materials such as Velcro.TM., or the like. Splints and wraps may extend along the wrist and beside a portion of or the complete length of the hand.
While assisting the bowler by providing added support and limiting relative movement, these devices also have a number of disadvantages. For example, splints and wraps generally require various adjustments to ensure a proper fit to the bowler's hand and wrist. Moreover, as they are generally firmly strapped to the wrist and hand to partially immobilize the hand and to minimize relative movement between the wrist and forearm, splints and wraps can be quite uncomfortable. Thus, such devices can be particularly cumbersome and uncomfortable when the bowler is resting, as between frames. Further, because the device may be cumbersome and difficult to properly place on the hand, the bowler may be hesitant to remove or even loosen the device when resting. While gloves may be more comfortable, they do not provide the support or level of immobilization of splints or wraps.
Additionally, while such bowling aids are available in various sizes, they generally do not provide an optimal fit and are not easily adjusted to different bowlers. Likewise, such devices are not readily adjustable to provide a different feel or form for consecutive ball deliveries.


A valve includes an air inlet for air coming from a first part of an engine intake passage, which is positioned upstream of a throttle valve and an air outlet for air moving toward a second part of the intake passage which is positioned downstream of the throttle valve. A hollow tubular element is connected to the air inlet and has primary connecting orifices between the air inlet and the air outlet. A movable obturator is housed within the tubular element. A magnetic core and winding is energized by an electrical control unit to generate a magnetic field to move a conical edge of the obturator to selectively open the primary connecting orifices to obtain laminar air flow across the primary connecting orifices, with this laminar air flow being directly proportional to the air passage section provided by the opened primary connecting orifices.

1. Field of the Invention
The invention relates to an electromagnetically-controlled valve to control an additional air amount for intervening opportunity on the amount of the fuel air mixture delivered by feed equipment of an internal combustion engine. More particularly, this invention relates to a valve of the above-mentioned type which controls a connecting pipe disposed between two zones of an intake passage. These zones are positioned upstream and downstream of a throttle valve respectively, in order to obtain an additional air flow determined according to the requirements of the operating engine.
2. Description of the Prior Art
Generally, devices are known which control additional air flow between the various parts of the feed equipment and which are placed upstream and downstream of the throttle valve. Such devices provide a by-pass channel interconnecting a part of the intake passage located upstream of the throttle valve, with a part of the intake passage located downstream of the throttle valve. Also, in the by-pass channel there is a device to control the air flow, like a fixed section housing or an adjustable section bushing, by a conic drill of an adjusting screw.
In such devices, it is impossible to vary the controlling bushing section during operation of the engine in order to adapt the additional air flow to the working requirements of the engine itself.

Electromagnetically-controlled valve, suitable for controlling an additional air flow in a feed equipment for an internal combustion engine


Apparatus, methods, systems and devices for identifying and tracking a human hand in a video. The steps for identifying the hand includes detecting parallel lines (bars), detecting curved fingertips (curves), grouping the detected parallel lines and curved fingertips according to a parallel line decision tree and a curved fingertip decision tree, respectively, and merging the parallel line group and the curved fingertip group to identify candidate hands.

Tracking in unconstrained and cluttered environments is a difficult task, especially when the object of interest is articulated. When a tracker fails, re-initialization is needed. In systems that are not self initialized, the initial structure from the manual initialization is assumed to be preserved over time for self correction. Even if an online model of the object is kept, it is not easy to determine automatically if the tracking has failed and when.
Tracking has been a well researched area in computer vision. There are numerous tracking systems such as Kanade-Lucas-Tomasi (KLT) Feature Tracker described in C. Tomasi and T. Kanade, Detection and tracking of point features, Technical Report CMU-CS-91-132, Carnegie Mellon University (April 1991) and mean shift approach described in D. Comaniciu and P. Meer, Mean shift: A robust approach toward feature space analysis, Pattern Analysis and Machine Intelligence, 24(5):603-619, (2002). The common problems of the prior art algorithms is initialization and self-correction.
Another problem with prior art detectors is that they have a high number of false positives (approximately 2 false positives per detection) and detection is not possible in some frames due to self occlusion and inability to detect the object of interest, such as finger primitives in low resolution images. Hand tracking is important in many applications including HCI, surveillance, gesture recognition and understanding human-human interactions. Prior art systems fail to track hands in uncontrolled environments, limiting them to simple gesture recognition problems with uniform background. In these systems, initialization usually comes from stationary hands in the system either by observing the hand for a short time frame, building pre-computed skin color histogram by training or manual initialization. Most prior art systems are unable to recover when the tracking fails.
Although some prior art describes methods for hand detection alone, such as the methods described in M. Kolsch and M. Turk. Robust hand detection. In Proc. Intl. Conf. Hand and Gesture Recognition, (2004) pp. 614-619 and Q. Yuan, S. Sclaroff, and V. Athitsos, Automatic 2d hand tracking in video sequences, In Proc. IEEE work, Motion and Video Computing, (2005) pp. 250 256, in most prior art systems the hand location is accepted as known or found through simple skin detection.
The skin detector is either trained on the skin color that is obtained from the face R. Rosales, V. Athitsos, L. Sigal, and S. Sclaroff. 3d hand pose reconstruction using specialized mappings, In Proc. Intl. Conf. Computer Vision, (2001), pp. 378-387, or as in the more frequent case, on skin color extracted from the training images as described in Bretzner et al, Hand gesture recognition using multi-scale color features, hierarchical models and particle filtering, In Proc. Intl. Conf. Hand and Gesture Recognition, pp. 423-428, (2002). However, the prior art systems fail under poor lighting conditions or when tracking skin colors that they are not trained for.
Aside from many systems that employ skin color based hand detection V. I. Pavlovic, R. Sharma, and T. Huang, Visual interpretation of hand gestures for human-computer interaction: A review. Pattern Analysis and Machine Intelligence, pp. 677-695, (1997); Rosales et al., 3d Hand pose reconstruction using specialized mappings, In. Proc. Intl. Conf. Computer Vision, (2001), pp. 378-387; and Y. Wu and T. Huang, View-independent recognition of hand postures, In Proc. Intl. Conf. Computer Vision and Pattern Recognition, (2000), pp. 2088-2094 there are few systems that operate in an appearance-based detection framework.
Kolsch and Turk discribed a system for detecting hands based on Ada-Boost. Their approach is view-specific and limited to a few postures of the hand. Yuan disclosed a hand detector, where detection of the hand successfully depends on continuous movement of the hands, therefore requires video as input. Moreover, in this video the hand posture is required to change, such that there is no correspondence between the hand regions among the frames that are being compared. Bretzner et al. use a hand detector before recognizing the hand posture; however their system performs poorly if a prior on skin color is not used.
Stenger et. al. applies hand detection and tracking in the same framework B. Stenger. Model-Based Hand Tracking Using A Hierarchical Bayesian Filter. PhD thesis, University of Cambridge, Cambridge, UK, (March 2004) and B. Stenger, A. Thayananthan, P. H. S. Torr, and R. Cipolla. Hand pose estimation using hierarchical detection. In Proc. Intl. work. Human Computer Interaction, (2004) pp. 105-116, but the detection is limited to both specific skin color and a hand pose. Another method for tracking is accomplished by building a 3-D model of the hand as described by Lin et. al. Hand tracking using spatial gesture modeling and visual feedback for a virtual dj system. In Proc. Fourth intl. conf. Multimodal Interfaces, (2002), pp. 197-202, also applies detection and tracking, but skin color is used to extract the hand, thus reducing generality.
Moreover, the hand is assumed to extend from the right hand side of the image, and assumed to exist in the scene. They use "U" shaped fingertip patterns to detect fingertips in already detected hands. Another hand tracker to mention is disclosed by Rehg et. al., Visual tracking of high dof articulated structures: An application to human hand tracking, In Proceedings of the 3rd European Conference on Computer Vision (ECCV '94), volume II, (May 1994), pp. 35-46 where the authors describe methods and systems that track simple features of the hand instead of tracking the hand in its entirety. However, they use a simple background for tracking.

Self correcting tracking of moving objects in video

University of Central Florida Research Foundation, Inc.


An optimum perturbation apparatus and method in a multi-antenna, multi-user communication system are provided. In the optimum perturbation method, upon receipt of modulation symbols, channel responses are decomposed into eigenvalues and eigenvectors by Single Value Decompositin (SVD) and a distortion value of the modulation symbols is estimated using the eigenvectors and the eigenvalues to minimize noise and interference power. The modulation symbols are precoded by combining the modulation symbols with the estimated distortion value.

1. Field of the Invention
The present invention relates generally to a multi-antenna multi-user communication system, and in particular, to an optimum perturbation apparatus and method.
2. Description of the Related Art
In a wireless communication system where a Base Station (BS) with multiple antennas send data to multiple users simultaneously, channel inversion, regularized inversion, vector perturbation, and regularized perturbation are used for precoding.
The channel inversion scheme, also called zero-forcing precoding, is simplest in that users receive their own data symbols without any coordination among them. The transmitted signal with channel inversion is given by Equation (1),
                    x        =                                            P                                      r                                                                                H                H                                                          (                                  HH                  H                                )                                                    -              1                                          u                                    (        1        )            where r is a normalization factor expressed as ∥HH(HHH)−1u∥2, P is a transmitting power and u is a data vector. r can be increased to infinity due to inversion of a channel response matrix in a poor channel environment. As a consequence, Signal-to-Interference and Noise Ratio (SINR) may become very small.
To overcome the problem of the SINR decrease, the regularized inversion scheme uses HH(HHH+αI)−1 instead of HH(HHH)−1 in Equation (1). Thus, the transmitted signal is changed to Equation (2),
                    x        =                                            P                                      r                                                                                H                H                                                          (                                                      HH                    H                                    +                                      α                                                                                I                                                  )                                                    -              1                                          u                                    (        2        )            where r=∥HH(HHH+αI)−1u∥2, I is a unitary matrix. SINR can be maximized by selecting an optimum value of α with which r is bounded.
In the vector perturbation scheme, a data vector u is perturbed by an integer-offset vector. Compared to the regularized inversion scheme that maximizes SINR without using a modulo operation at a receiver, the vector perturbation scheme finds an integer vector maximizing SINR and shifts the constellation as much as the integer vector under the assumption of the modulo operation at the receiver. The transmitter sends a signal represented by Equation (3)
                    x        =                                            P                                      r                                                                                H                H                                                          (                                  HH                  H                                )                                                    -              1                                                      (                          u              +                              τ                                                                                1                                      )                                              (        3        )            where r=∥HH(HHH)−1(u+τl)∥2, τ is a positive real number, and l is a Kx1 complex vector. The receiver recovers the received signal by eliminating τl by a modulo operation. To maximize the SINR of the received signal, the BS chooses l to minimize r as defined by Equation (4),
                    1        =                              argmin                          1              ′                                                                                                                                                    H                      H                                                                                (                                              HH                        H                                            )                                                                            -                    1                                                                                (                                      u                    +                                          τ                                                                                1                        ′                                                                              )                                                                    2                                              (        4        )            This is an integer-lattice least-square problem, which is solved by a sphere encoder.
Finally, the regularized perturbation scheme simply combines the regularized inversion scheme with the vector perturbation scheme. The transmitted signal is defined by Equation (5),
                    x        =                                            P                        r                                                                        H                H                                                          (                                                      HH                    H                                    +                                      α                                                                                I                                                  )                                                    -              1                                                      (                          u              +                              τ                                                                                1                                      )                                              (        5        )            where r=∥HH(HHH+αI)−1(u+τl)∥2. As with the vector perturbation scheme, to maximize the SINR of the received signal, l is chosen to minimize r as reflected by Equation (6) as follows.
                    1        =                              argmin                          1              ′                                                                                                                                                    H                      H                                                                                (                                                                        HH                          H                                                +                                                  α                                                                                I                                                                    )                                                                            -                    1                                                                                (                                      u                    +                                          τ                                                                                1                        ′                                                                              )                                                                    2                                              (        6        )
As the vector perturbation scheme is additionally used after the regularized inversion scheme, the regularized perturbation scheme neither maximizes SINR and nor optimizes the parameter α for the regularized inversion scheme. Therefore, interference still remains in the receiver signal after the modulo operation.

Optimum perturbation apparatus and method in a multi-antenna multi-user communication system

Korea Advanced Institute of Science and Technology


Flat electrolytic capacitors, particularly, for use in implantable medical devices (IMDs), and the methods of fabrication of same are disclosed. The capacitors are formed with an electrode stack assembly comprising a plurality of stacked capacitor layers each comprising an anode sub-assembly of at least one anode layer, a cathode layer and separator layers wherein the anode and cathode layers have differing dimensions that avoid electrical short circuits between peripheral edges of adjacent anode and cathode layers but maximize anode electrode surface area. The electrolytic capacitor is formed of a capacitor case defining an interior case chamber and case chamber periphery, an electrode stack assembly of a plurality of stacked capacitor layers having anode and cathode tabs disposed in the interior case chamber, an electrical connector assembly for providing electrical connection with the anode and cathode tabs through the case, a cover, and electrolyte filling the remaining space within the interior case chamber. The plurality of capacitor layers and further separator layers are stacked into the electrode stack assembly and disposed within the interior case chamber such that the adjacent anode and cathode layers are electrically isolated from one another. The anode layer peripheral edges of the anode sub-assemblies of the stacked capacitor layers extend closer to the case side wall than the cathode peripheral edges of the cathode layers of the stack of capacitor layers throughout a major portion of the case chamber periphery. The separator layer peripheral edges extend to the case periphery and space the anode layer peripheral edges therefrom. Any burrs, debris or distortions along or of any of the anode layer peripheral edges causing the anode layer edges to effectively extend in the electrode stack height direction causes the anode layer peripheral edges having such tendency to contact an adjacent anode layer. In this way, anode layer surface area is maximized, and short circuiting of the anode layers with the cathode layers is avoided. A case liner can also be disposed around the electrode stack assembly periphery.

A wide variety of IMDs are known in the art as described in the above-referenced parent application Ser. No. 09/531,352, and the provisional application that it claims priority from, and in commonly assigned U.S. Pat. No. 6,006,133. Of particular interest are implantable cardioverter-defibrillators (ICDs) that deliver relatively high energy cardioversion and/or defibrillation shocks to a patient's heart when a malignant tachyarrhythmia, e.g., atrial or ventricular fibrillation, is detected. Current ICDs typically possess single or dual chamber pacing capabilities for treating specified chronic or episodic atrial and/or ventricular bradycardia and tachycardia and were referred to previously as pacemaker/cardioverter/defibrillators (PCDs). Earlier developed automatic implantable defibrillators (AIDs) did not have cardioversion or pacing capabilities. For purposes of the present invention ICDs are understood to encompass all such IMDs having at least high voltage cardioversion and/or defibrillation capabilities.
Generally speaking, it is necessary to employ a DC—DC converter within an ICD implantable pulse generator (IPG) to convert electrical energy from a low voltage, low current, electrochemical cell or battery enclosed within the IPG housing to a high voltage energy level stored in one or more high energy storage capacitor, as shown for example, in commonly assigned U.S. Pat. No. 4,548,209. The conversion is effected upon confirmation of a tachyarrhythmia by a DC—DC "flyback" converter which includes a transformer having a primary winding in series with the battery and a secondary winding in series with the high energy capacitor(s) and an interrupting circuit or switch in series with the primary coil and battery that is periodically opened and closed during a charging cycle. Charging of the high energy capacitor is accomplished by inducing a voltage in the primary winding of the transformer creating a magnetic field in the secondary winding when the switch is closed. The field collapses when the current in the primary winding is interrupted by opening the switch, and the collapsing field develops a current in the secondary winding which is applied to the high energy capacitor to charge it. The repeated interruption of the supply current charges the high energy capacitor to a desired level of several hundred volts over a charging time of the charge cycle. Then, the energy is rapidly discharged from the high voltage capacitor(s) through cardioversion/defibrillation electrodes coupled to the IPG through ICD leads and arranged about or in a heart chamber or vessel if the tachyarrhythmia is confirmed as continuing at the end of the charge time. The cardioversion/defibrillation shocks effected by discharge of such capacitors are typically in the range of about 25 to 40 Joules. The process of delivering cardioversion/defibrillation shocks in this way may be repeated if an earlier delivered cardioversion/defibrillation shock does not convert the tachyarrhythmia to a normal heart rhythm.
Energy, volume, thickness and mass are critical features in the design of ICD pulse generators that are coupled to the ICD leads. The battery(s) and high voltage capacitor(s) used to provide and accumulate the energy required for the cardioversion/defibrillation shocks have historically been relatively bulky and expensive. Presently, ICD IPGs typically have a volume of about 40 to about 60 cc, a thickness of about 13 mm to about 16 mm and a mass of approximately 100 grams.
It is desirable to reduce the volume, thickness and mass of such capacitors and ICD IPGs without reducing deliverable energy. Doing so is beneficial to patient comfort and minimizes complications due to erosion of tissue around the ICD IPG. Reductions in size of the capacitors may also allow for the balanced addition of volume to the battery, thereby increasing longevity of the ICD IPG, or balanced addition of new components, thereby adding functionality to the ICD IPG. It is also desirable to provide such ICD IPGs at low cost while retaining the highest level of performance. At the same time, reliability of the capacitors cannot be compromised.
Various types of flat and spiral-wound capacitors are known in the art, some examples of which are described as follows and/or may be found in the patents listed in Table 1 of the above-referenced parent patent application Ser. No. 09/531,352.
Prior art high voltage electrolytic capacitors used in ICDs have two or more anode and cathode layers (or "electrodes") and operate at room or body temperature. Typically, the capacitor is formed with a capacitor case enclosing an etched aluminum foil anode, an aluminum foil or film cathode, and a Kraft paper or fabric gauze spacer or separator impregnated with a solvent based liquid electrolyte interposed therebetween. A layer of aluminum oxide that functions as a dielectric layer is formed on the etched aluminum anode, preferably during passage of electrical current through the anode. The electrolyte comprises an ion producing salt that is dissolved in a solvent and provides ionic electrical conductivity between the cathode and the aluminum oxide dielectric. The energy of the capacitor is stored in the electrostatic field generated by opposing electrical charges separated by the aluminum oxide layer disposed on the surface of the anode and is proportional to the surface area of the aluminum anode. Thus, to minimize the overall volume of the capacitor one must maximize anode surface area per unit volume without increasing the capacitor's overall (i.e., external) dimensions. The separator material, anode and cathode layer terminals, internal packaging, electrical interconnections, and alignment features and cathode material further increase the thickness and volume of a capacitor. Consequently, these and other components in a capacitor and the desired capacitance limit the extent to which its physical dimensions may be reduced.
Some ICD IPGs employ commercial photoflash capacitors similar to those described by Troup in "Implantable Cardioverters and Defibrillators," Current Problems in Cardiology, Volume XIV, Number 12, December 1989, Year Book Medical Publishers, Chicago, and as described in U.S. Pat. No. 4,254,775. The electrodes or anode and cathodes are wound into anode and cathode layers separated by separator layers of the spiral. Anode layers employed in such photoflash capacitors typically comprise one or two sheets of a high purity (99.99%), porous, highly etched, anodized aluminum foil. Cathode layers in such capacitors are formed of a non porous, highly etched aluminum foil sheet which may be somewhat less pure (99.7%) respecting aluminum content than the anode layers. The separator formed of one or more sheet or layer of Kraft paper saturated and impregnated with a solvent based liquid electrolyte is located between adjacent anode and cathode layers. The anode foil thickness and cathode foil thickness are on the order of 100 micrometers and 20 micrometers, respectively. Most commercial photoflash capacitors contain a core of separator paper intended to prevent brittle, highly etched aluminum anode foils from fracturing during winding of the anode, cathode and separator layers into a coiled configuration. The cylindrical shape and paper core of commercial photoflash capacitors limits the volumetric packaging efficiency and thickness of an ICD IPG housing made using same.
The aluminum anodes and cathodes of aluminum electrolytic capacitors generally each have at least one tab extending beyond their perimeters to facilitate electrical connection of all (or sets of) the anode and cathode layers electrically in parallel to form one or more capacitor and to make electrical connections to the exterior of the capacitor case. Tab terminal connections for a wound electrolytic capacitor are described in U.S. Pat. No. 4,663,824 that are laser welded to feedthrough pin terminals of feedthroughs extending through the case. Wound capacitors usually contain two or more tabs joined together by crimping or riveting.
Flat electrolytic capacitors have also been disclosed in the prior art for general applications as well as for use in ICDs. More recently developed ICD IPGs employ one or more flat high voltage capacitor to overcome some of the packaging and volume disadvantages associated with cylindrical photoflash capacitors. For example, U.S. Pat. No. 5,131,388 discloses a flat capacitor having a plurality of stacked capacitor layers each comprising an "electrode stack sub-assembly". Each capacitor layer contains one or more anode sheet forming an anode layer having an anode tab, a cathode sheet or layer having a cathode tab and a separator for separating the anode layer from the cathode layer. In the '388 patent, the capacitor stack of stacked capacitor layers is encased within a non-conductive, polymer envelope that is sealed at its seams and fitted into a chamber of a conductive metal, capacitor case or into a compartment of the ICD IPG housing, and electrical connections with the capacitor anode(s) and cathode(s) are made through feedthroughs extending through the case or compartment wall. The tabs of the anode layers and the cathode layers of all of the capacitor layers of the stack are electrically connected in parallel to form a single capacitor or grouped to form a plurality of capacitors. The aluminum anode layer tabs are gathered together and electrically connected to a feedthrough pin of an anode feedthrough extending through the case or compartment wall. The aluminum cathode layer tabs are gathered together and electrically connected to a feedthrough pin of a cathode feedthrough extending through the case or compartment wall or connected to the electrically conductive capacitor case wall.
Many improvements in the design of flat aluminum electrolytic capacitors for use in ICD IPGs have been disclosed, e.g., those improvements described in "High Energy Density Capacitors for Implantable Defibrillators" presented by P. Lunsmann and D. MacFarlane at CARTS 96: 16th Capacitor and Resistor Technology Symposium, 11-15 Mar. 1996, and at CARTS-EUROPE 96: 10th European Passive Components Symposium, 7-11 Oct. 1996, pp. 35-39. Further features of flat electrolytic capacitors for use in ICD IPGs are disclosed in U.S. Pat. Nos. 4,942,501; 5,086,374; 5,146,391; 5,153,820; 5,562,801; 5,584,890; 5,628,801; and 5,748,439, all issued to MacFarlane et al.
A number of recent patents including U.S. Pat. No. 5,660,737 and U.S. Pat. Nos. 5,522,851; 5,801,917; 5,808,857; 5,814,082; 5,908,151; 5,922,215; 5,926,357; 5,930,109; 5,968,210 and 5,983,472, all assigned to the same assignee, disclose related flat electrolytic capacitor designs for use in ICDs. In several of these patents, internal alignment elements are employed as a means for controlling the relative edge spacing of the anode and cathode layers from the conductive capacitor case. In these patents, each anode layer and cathode layer is provided with an outwardly extending tab, and the anode and cathode tabs are electrically connected in common to a feedthrough pin and a step feature of the conductive capacitor case, respectively. The cathode tabs are gathered together against the step feature and ultrasonically welded together and to the step feature. In the '357 patent, the anode tabs are laser welded to one end of an aluminum ribbon that is ultrasonically welded at its other end to an aluminum layer that is ultrasonically welded to the terminal pin. The feedthrough terminal pin is electrically isolated from and extends outside and away from the case to provide an anode connection pin. A cathode connection pin is attached to the case and extends outwardly therefrom. The anode and cathode connection pins are electrically connected into the DC—DC converter circuitry, but the attachment mechanism is not described in any detail.
Thus, the anode layers and the cathode layers of each capacitor layer in the stack are electrically coupled together to form one or more capacitor cathode and anode. In assembling a capacitor of these types, it is necessary that the anode and cathodes remain separated electrically from one another by the separators placed between adjoining cathode and anode layers to prevent short circuiting. It is also important that a minimum separation between the anode and cathode layers be maintained to prevent arcing therebetween, or between an anode layer of the anode and the case, when the case is conductive and coupled to the cathode. In cylindrical capacitors, such spacing is typically maintained at the electrode edges or peripheries by providing separator overhang at the top and bottom of the anode and cathode winding. In commercial cylindrical capacitors, the amount of separator overhang is typically on the order of 0.050 to 0.100 inches (0.127 to 0.254 mm). In addition, the anode and cathode are aligned precisely and coiled tightly to prevent movement of the anode, cathode and separator during subsequent processing and use.
In flat electrolytic capacitors, anode to cathode alignment is typically maintained through the use of adhesive electrolyte as disclosed in the above-referenced patents to MacFarlane, supra. The above-referenced '851 patent describes a flat aluminum electrolytic capacitor wherein the housing of the capacitor has at least two internal alignment members.
Those alignment members necessarily add volume to the capacitor while taking away from the total amount of "active" electrode material available, thereby decreasing the energy density of the capacitor. Moreover, the above-referenced '082 patent describes use of inwardly directed registration notches in the capacitor electrode stack periphery that are used during registration of the stack within the interior case chamber which reduce capacity. The '082 patent also provides for cathode layer peripheral edges that extend outward beyond the anode layer peripheral edges through a major portion of the electrode stack periphery that can electrically contact the case. This approach is wasteful of space that could be used by anode layers to increase capacity.

Implantable medical device having flat electrolytic capacitor with differing sized anode and cathode layers


Disclosed is a reinforced membrane-seal assembly, the reinforced membrane-seal assembly including: an inner region and a border region and wherein the inner region includes ion-conducting component and the border region includes seal component; wherein first and second planar porous reinforcing components each extend across the inner region into the border region and wherein the pores of each of the first and second planar porous reinforcing components in the inner region are impregnated with ion-conducting component and the pores of each of the first and second planar porous reinforcing components in the border region are impregnated with seal component is disclosed. Also disclosed is a catalyst-coated reinforced membrane-seal assembly, a reinforced membrane-seal electrode assembly and an electrochemical device including the reinforced membrane-seal assembly.

A fuel cell is an electrochemical cell comprising two electrodes separated by an electrolyte. A fuel, such as hydrogen or an alcohol, such as methanol or ethanol, is supplied to the anode and an oxidant, such as oxygen or air, is supplied to the cathode. Electrochemical reactions occur at the electrodes, and the chemical energy of the fuel and the oxidant is converted to electrical energy and heat. Electrocatalysts are used to promote the electrochemical oxidation of the fuel at the anode and the electrochemical reduction of oxygen at the cathode.
In the hydrogen-fuelled or alcohol-fuelled proton exchange membrane fuel cells (PEMFC), the electrolyte is a solid polymeric membrane, which is electronically insulating and proton conducting. Protons, produced at the anode, are transported across the membrane to the cathode, where they combine with oxygen to form water. The most widely used alcohol fuel is methanol, and this variant of the PEMFC is often referred to as a direct methanol fuel cell (DMFC).
The principal component of the PEMFC is known as a membrane electrode assembly (MEA) and is essentially composed of five layers. The central layer is the polymeric ion-conducting membrane. On either side of the ion-conducting membrane there is an electrocatalyst layer, containing an electrocatalyst designed for the specific electrocatalytic reaction. Finally, adjacent to each electrocatalyst layer there is a gas diffusion layer. The gas diffusion layer must allow the reactants to reach the electrocatalyst layer and must conduct the electric current that is generated by the electrochemical reactions. Therefore the gas diffusion layer must be porous and electrically conducting.
Conventionally, the MEA can be constructed by a number of methods outlined hereinafter:
(i) The electrocatalyst layer may be applied to the gas diffusion layer to form a gas diffusion electrode. Two gas diffusion electrodes can be placed either side of an ion-conducting membrane and laminated together to form the five-layer MEA;
(ii) The electrocatalyst layer may be applied to both faces of the ion-conducting membrane to form a catalyst-coated ion-conducting membrane. Subsequently, gas diffusion layers are applied to both faces of the catalyst-coated ion-conducting membrane.
(iii) An MEA can be formed from an ion-conducting membrane coated on one side with an electrocatalyst layer, a gas diffusion layer adjacent to that electrocatalyst layer, and a gas diffusion electrode on the other side of the ion-conducting membrane.
Conventionally, the MEA is constructed so that the central polymeric ion-conducting membrane extends to the edge of the MEA, with the gas diffusion layers and electrocatalyst layers being smaller in area than the membrane such that there is an area around the periphery of the MEA which comprises ion-conducting membrane only. The area where no electrocatalyst is present is a non-electrochemically active region. Film layers, typically formed from non-ion conducting polymers, are generally positioned around the edge region of the MEA on the exposed surfaces of the ion-conducting membrane where no electrocatalyst is present to seal and/or reinforce the edge of the MEA. An adhesive layer may be present on one or both surfaces of the film layer.
The component layers in the MEA are typically bonded by a lamination process. Typically, much of the polymeric ion conducting material used in the membrane extends beyond the electrochemically active region into a non-electrochemically active region, often by up to several centimeters. In low geometric area MEAs this non-electrochemically active region can contribute to as much as 50% of the entire MEA geometric area. The membrane which extends beyond the electrochemically active area does not contribute to the activity and performance. The polymeric ion-conducting membrane is one of the most costly components in the fuel cell, and it is thus desirable to minimise its usage. Furthermore, the seal film layers positioned around the edge region of the MEA are typically formed by taking a roll of film and cutting out a central region to create a window frame which is then positioned around the edge of the MEA. Thus a significant proportion of the seal film material is also wasted. It is common practice that the polymeric ion-conducting membrane also comprises a reinforcement material, such as a planar porous material, embedded within the thickness of the membrane, to provide for improved mechanical strength of the membrane and thus increased durability of the MEA and lifetime of the fuel cell.


An ornamental liquid color box includes stationary clear containers fixedly mounted on a cover of a seat. Propellers are provided on the seat to propel liquid colors flowing into the seat to liquid passages that are led to upper storing zones of the containers. Liquid colors sent to the upper storing zones then moves into narrowed middle display zones to form flattened and irregular drips before reaching lower storing zones of the containers and entering the seat again to complete a cycle of movement of the liquid colors in the liquid color box. The whole liquid color box need not be manually or mechanically turned to maintain continuous circulation of the liquid colors in the liquid color box. The propellers are driven to rotate by driving means that may be coil windings or a combination of a motor and magnet-loaded driving and driven gear wheels. No leakproof means, such as shaft seals, are required for the liquid color box.

The present invention relates to an ornamental liquid color box, and more particularly to an ornamental liquid color box that has stationary liquid color containers and simplified driving mechanism to easily cause liquid colors to circulate in the containers and show changeful colors and views.
The liquid color box is a popular ornament and typically includes a transparent liquid color container divided into two or more spaces from front to rear side of the container. Generally, two spaces, namely, a front and a rear space, would be sufficient for the liquid color box to achieve an ornamental function thereof. Each space of the container further includes expanded upper and lower areas for storing one liquid color, and a narrowed middle area for displaying flattened and therefore differently shaped liquid color drips. Liquid colors stored in the upper storing areas flow downward to pass the middle displaying areas in a form of flattened drips that have irregular shapes. The irregularly shaped color drips in the two spaces of the container overlap one another to show changeful colors.
To enable circulation of the liquid colors in the container to provide continuous display effect, the containers of currently available liquid color boxes must be either manually or mechanically turnable. In the latter case, the liquid color containers are usually a round member and driven by motor and frictional gearing. Since the container of liquid color box usually has a certain volume and weight, it is necessary for the motor and frictional gearing to generate considerable driving force to rotate the container. Moreover, to enable the container to rotate stably without producing noise, complicate supporting seat or shaft is usually needed. As a result, conventional liquid color boxes tend to be clumsy and complicate and could not be massively produced to lower manufacture costs thereof.
It is therefore desirable to develop an improved liquid color box that eliminates drawbacks existing in the conventional liquid color boxes.


A ship lock utilizes a hydraulic turbine and/or pump-turbine to regulate the discharge flow rates through the ship lock to an approximate constant value during the majority of the water transfer cycle resulting in a diminishing of total energy of head losses and to enable the recuperation of the unused hydraulic energy for generation as electricity. The difference in water levels on opposite sides of the ship lock constitutes potential hydraulic energy. By regulating the discharge, the total head losses over a given period of time diminish very significantly, thus giving an opportunity for optimization of hydraulic energy recuperation.

A ship lock, often in a canal system, operates to connect two bodies of water at different water levels by alternate lowering and raising of the water level in the ship lock. Ship locks are operated using the gravity force to transfer a volume of water from one side of a lock gate to its other side. Once water levels have equilibrated, the lock gate can be opened for the ship to move through the gate.
U.S. Pat. No. 4,310,769 issued Jan. 12, 1982 teaches a ship lock system having one or more underground hydroelectric pumped-storage units which generate electrical energy. Water from the ship lock is drained to a lower reservoir when the ship lock water level is lowered. The water passes through a penstock and past a pump-turbines to generate electrical energy. The reservoir collects the water instead of allowing the water to be lost downstream. The pump-turbines then pump the water from the reservoir upward into the ship lock through the penstocks to raise the water level in the ship lock. The electrical power for accomplishing the pumping action can be supplied from other conventional energy sources as well as from tidal, wind, solar and other emerging energy sources. Hence water is conserved by the use of the pump-turbine. While this operation conserves water, it is a net consumer of electricity as the electricity generated by lowering the water level in the ship lock will be less than the electricity needed to pump the water back up into the ship lock against the forces of gravity and other losses.
German patent application DE 11 30 766 published May 30, 1962, discloses a power station located next to a lock having a pump-turbine for enabling faster and cheaper operation of the lock where one of the generators of the power station can be used to speed up the lock operation.
However, neither of these two patents teach the net recuperation of the unused hydraulic energy to generate electricity. In a traditionally operated ship lock, once the operating valves are opened, the free discharge of water through the system is proportional to the square root of the differential head from the two sides of the lock gate. Thus, the discharge rate is usually high in the beginning, and then diminishes until the discharge rate becomes relatively small towards the end of the water transfer cycle making it difficult to recuperate hydraulic energy for generation of electricity. Hence there is a need to be able to have a net recuperation of unused hydraulic energy to generate electricity which takes into consideration the problems associated with changes in the discharge rate of the water flow.


In a number of embodiments, an Electric Vehicle Supply Equipment (EVSE) connector (120), includes a plurality of charging lines (150, 151) configured to provide electrical charge to an electric vehicle (EV) (140) at least one control line (153, 154) configured to carry signals to control charging of the EV via the charging lines (150, 151) and a detector (170) that detects a thermal event, wherein in response to detecting a thermal event the detector (170) manipulates the at least one control line (153, 154) to alter charging of the EV via the charging lines (150, 151).

Electric Vehicle Supply Equipment (EVSE) is designed to operate in a manner that is simple, safe, ergonomic and cost-efficient. It is designed to provide safe alternating current (AC) power for on-board chargers of Electric Vehicles (EVs) or plug-in hybrid electric vehicles (PHEVs). In many instances, the EVSE comprises a charging connector that couples with an inlet on an EV or PHEV to create a circuit that can charge the vehicle. These coupling contacts are generally rated for a large number of use cycles during their lifetimes.

Thermal management of electric vehicle coupler contacts


An eyelash treatment device including an applicator equipped with a heater for softening a mascara composition which is solid at a room temperature. The applicator includes, in addition to a comb arranged along the length of the applicator, a heat radiator which is exposed on the applicator and is configured to have a continuous heating strip extending along the length of the applicator to receive the solid mascara composition for softening the composition by heat. Also, the heat radiator is configured to have a trough for holding the softened mascara composition. The comb projects from within the trough for delivering the softened mascara composition to the eyelashes when smoothening the eyelashes. Because the heating strip extends continuously along the length of the heat radiator without being interrupted by any member, the mascara composition can be loaded over the full length of the heating strip so as to be applied successfully and uniformly to the eyelashes from the applicator. Thus, the softened mascara composition can be successfully delivered to the eyelashes from the entire length of the comb or the applicator, leaving the solid mascara film on the eyelashes by being cooled.

1. Field of the Invention
The present invention relates to an eyelash treating device for applying the mascara composition to a user's eyelashes, and more particularly to such device designed for use of a solid mascara composition.
2. Description of the Related Art
There have been proposed in the art eyelash treating devices, such as WO 99/22782 including a applicator brush and heater combination. The applicator brush is designed to curl the eyelashes by application of heat, while applying the mascara composition of liquid or semi-liquid condition fetched from a container. However, due to the absence of the idea and structure for heating and softening the solid mascara composition which is solid at a room temperature, the applicator brush is practically impossible to use in combination with the solid mascara composition. In view of the problem, there is a need of providing a dedicated heating device which takes the full benefit of the solid mascara composition to apply the softened mascara composition successfully and uniformly to the eyelashes.