By way of example, a data storage system may comprise, a non-transitory storage device storing data blocks in chunks, and a storage logic coupled to the non-transitory storage device that manages storage of data on the storage device. The storage logic is executable to receive a data stream for storage in a non-transitory storage device, the data stream including one or more data blocks, analyze the data stream to determine a domain, retrieve a pre-configured reference set based on the domain, and deduplicate the one or more data blocks of the data stream using the pre-configured reference set.

The present disclosure relates to data deduplication.
To improve storage utilization, data deduplication is often used to eliminate repeating data. Some approaches substitute reference pointers for redundant data segments, such as variable-length blocks, in a given data set. This can increase the amount of information that can be stored or transmitted over networks. Other solutions include single-instance storage configured to eliminate the repeat storage of identical files.
Some existing solutions apply similarity-based content matching to identify similarities between a set of documents, as opposed to an exact match. For instance, content matching has been used in search engine implementations and in building dynamic random access memory (DRAM)-based caches such as, hash lookup-based deduplication. The existing solutions for DRAM-based caches utilize exact matching and not similarity-based deduplication (which identifies approximate matches) because of technical hurdles with using similarity-based deduplication in storage devices.
For example, the architecture of flash-based storage devices limits the amount of available data blocks for storing information. As such, substantial overhead in block carry-over exists in flash management, which can influence performance of flash storage devices. As the concentration of a flash storage device increases, the number and size of data blocks is increased, resulting in even more overhead aid lower performance for write and rewrite operations. Memory waste can also occur. The existing solutions are unable to effectively minimize this memory waste, as well as efficiently manage and construct reference sets when deduplicating data in storage devices, such as flash storage devices.

Reference set construction for data deduplication


Heat-dissipating assemblies may comprise mounting tabs attached to heat-generating electrical components at a first surface of each mounting tab. An opposing second surface of each mounting tab may be at least substantially coplanar with the second surfaces of the other mounting tabs. A heat sink element may be attached to the second surfaces of at least some of the mounting tabs. Methods of assembling heat-dissipating assemblies may comprise attaching first surfaces of mounting tabs to at least substantially planar assembly surfaces of an assembly fixture such that the first surfaces of the mounting tabs are at least substantially coplanar with one another. Opposing second surfaces of the mounting tabs may be attached to heat-generating electrical components. The assembly fixture may be removed. A heat sink element may be attached to the at least substantially coplanar first surfaces of at least some of the mounting tabs.

Cooling heat-generating components, such as integrated circuit devices, is often desirable to ensure their proper operation and to extend their useful life. A trend in contemporary circuit design is to provide multiple heat-generating components on a printed circuit board. A consequence of providing multiple heat-generating components on a printed circuit board, which may include integrated circuit devices operating at relatively high speeds, is substantial heat production that may be detrimental to the operation and life of those components. Conventionally, heat sinks are used to transfer heat from the heat-generating components to an area where the heat can be dissipated, such as the atmosphere. Alternatively, or in addition, adequate forced ventilation is provided to remove the heat from the heat sink.
Some conventional approaches to thermal management of packaged electronic devices require the mating of individual heat sinks with individual components. The use of individual heat sinks can be expensive and the associated installation may be labor intensive. Further, as more heat-generating components are provided onto ever-smaller printed circuit boards, each heat sink must be accurately aligned with its neighbor to ensure proper function.
Other conventional heat sinks are also adapted for cooling a multiplicity of heat-generating components. Variations in the manufacturing and assembly processes, however, frequently result in seemingly identical components that have top attachment surfaces, over which the heat sink is provided, at slightly different heights. Possible sources of height differences include, for example, variances in the size of solder balls used to attach components to a substrate, variances in bends of leads used for component attachment, variances in thickness of solder connections, and dimensional variances in other attachment features used for this purpose. Moreover, different components having top attachment surfaces located at different heights may often be provided on the same printed circuit board. In a conventional configuration resulting in different component height, highly compressible thermally conductive gap pads or gap filler materials may be used to fill gaps between the bottom of the heat sink and the top surfaces of the components to be cooled, enabling effective thermal transfer to the heat sink from the shorter components. Gap pads may be attached between the heat sink and the components by thermally conductive epoxy or by mechanical means, such as clamps or fasteners. Alternatively, the heat sink may be configured to deform in response to an applied downward force to contact the top surfaces of components and be attached thereto. Further, gap filler material, such as a thermal interface material (TIM), may also be provided to fill gaps between the heat sink and the components. Conventionally, TIMs are able only to fill relatively thin gaps because a thicker layer of TIM may not provide adequate heat dissipation. Any of these configurations, however, may result in inadequate heat transfer from components due to suboptimal, or failed, thermal attachments or may introduce unacceptable stress on thicker components having top surfaces most out of plane with the top surfaces of the remainder of the components.

Heat-dissipating assemblies and methods of assembling heat-dissipating assemblies


Compounds containing a substituted or unsubstituted allyl group directly bound to a chiral carbon atom are prepared enantioselectively. Starting reactants are either chiral or achiral, and may or may not contain an attached allyloxycarbonyl group as a substituent. Chiral ligands are employed, along with transition metal catalysts. The methods of the invention are effective in providing enantioconvergent allylation of chiral molecules.

Allylic alkylations form an important class of reactions in synthetic organic chemistry (Trost et al. (2002) Chem. Pharm. Bull. (Tokyo) 50:1–14; Hayashi et al. (1988) J. Org. Chem. 53: 113–120; Trost et al. (1997) J. Am. Chem. Soc. 119: 7879–7880; Sugimoto et al. (1997) J. Org. Chem. 62: 2322–2323; Satoshi et al, (2003) Chirality 15: 68–70). The unique reactivity of compounds containing allylic groups accounts for their utility in synthetic transformations and multi-step syntheses. Although numerous methods exist for adding allyl groups onto compounds displaying a variety of structures and functional groups, current limitations have generated much effort towards expanding the scope of the transformation.
A well-established approach towards allylic alkylation is via simple nucleophilic substitution. Under basic conditions, alcohols, amines and carbanion precursors such as malonates form nucleophiles that react with alkyl halides or triflates to form the corresponding O—, N— or C-alkylated products. As an example of this method, allylic alkylation of these nucleophilic substrates can be achieved using allyl halides. Regio- and stereocontrol over the alkylation product, however, is highly dependent upon the structure of the reactant.
An important subset of allylation reactions in general is the formation of α-allyl ketones. Allylation of allyl-enol carbonates is one approach toward this goal. As originally described (Tsuji et al. (1987) Acc. Chem. Res. 20: 140–145; Tsuji et al. (1983) Tetrahedron Lett. 24: 1793–1796; Tsuji et al. (1985) J. Org. Chem. 50: 1523–1529; Tsuji et al. (1983) Chem. Lett. 12: 1325–1326), a palladium catalyst is used in conjunction with a phosphine ligand such as PPh3. The reaction proceeds via decarboxylative degradation of the starting material to form, in situ, an electrophilic allyl moiety and a nucleophilic enolate. The reaction affords excellent regiocontrol, and occurs under essentially neutral conditions. Unfortunately, the allylation reported by Tsuji et al. displays no stereocontrol; the reaction results in a racemic mixture of α-allylcyclohexanone products. As a result of the lack of stereocontrol, this approach has since been used and reported as a synthetic tool only sparingly.
Synthetic methods for preparing α-quaternary carbons are generally more useful when the products are enantioenriched. Enantioselectivity has been achieved in allylation reactions for a limited pool of substrates using a Palladium catalyst in conjunction with chiral ligands. These systems have been essentially confined to allylation of β-diketones and β-ketoesters using prochiral electrophiles, or to α-aryl ketones and cyclic ketones that can only form a single enolate (Hayashi et al. (1988) J. Org. Chem. 53: 113–120; Sawamura et al., (1992) J. Am. Chem. Soc. 114: 2586–2592; Trost et al. (1997) J. Am. Chem. Soc. 119: 7879–7880; Kuwano, et al. (1999) J. Am. Chem. Soc. 121: 3236–3237; Trost et al. (1999) J. Am. Chem. Soc. 121: 6759–6760; You et al. (2001) Org. Lett. 3: 149–151; Trost et al. (2002) Angew. Chem. Int. Ed. 41: 3492–3495). In general, strongly basic conditions are required in order to form the reactive enolate intermediate. For example, Trost et al. (2002) describes the allylation of α-aryl ketones using the strongly basic reagents lithium diisoproplyamide or sodium 1,1,1,3,3,3-hexamethyldisilazide. Hayashi et al. described the enantioselective allylation of β-diketones using a palladium catalyst, while Trost et al. (1997) has shown similar results for β-ketoester substrates. Sugimoto et al. used chromium(III) complexes in order to catalyze enantioselective allylation reactions of aldehydes. Titanium(IV) catalysts were used by Satoshi et al. in order to enantioselectively allylate certain ketones.
In light of the limited success in developing enantioselective allylation reactions, there exists a need in the art for a method to prepare highly enantioenriched α-quaternary cycloalkanones and related compounds via enantioselective allylation. Such a method would, optimally, tolerate of a wide variety of functional groups on the substrate, require mild reaction conditions, and employ readily available catalyst/ligand systems. Also desirable is the ability to carry out the reaction on a broad range of structurally distinct compounds. Flexibility in the choice of the catalyst system is also highly desirable.

Enantioselective, catalytic allylation of ketones and olefins


A power conversion apparatus has a voltage type power convertor, a power control circuit for outputting a first active power reference signal for the voltage type power convertor based on a power reference value Pref and a detection value P of a power detector, a DC voltage detector for outputting a second active power reference signal for the voltage type power convertor based on a DC voltage reference value Vdref and a detection value Vd of the DC voltage detector, and a gate control circuit for firing switching elements in the voltage type power convertor based on both first and second active power reference signals.

1. Field of the Invention
The present invention relates to a power conversion apparatus capable of increasing the stability of a multi-terminal direct current power transmission system in which a plurality of voltage power conversion apparatuses are connected to a direct current line, and also capable of continuously maintaining the operation of remaining power conversion apparatuses even if a terminal fault caused by a system fault or a fault of one of the power conversion apparatus occurs.
2. Description of the Prior Art
FIG.9 is a diagram showing a configuration of a conventional power conversion apparatus that has been disclosed in the Japanese Laid-Open Publication Number JP-A-1-238430. FIG.9 shows only one of a plurality of power conversion apparatuses connected to a direct current line. In FIG.9, the reference number 300 designates a power conversion apparatus to convert a Direct Current (DC) power to an alternating current (AC) power or the AC power to the DC power, 20 indicates an AC system, and 30 indicates a DC system. The reference number 301 designates a voltage type power conversion apparatus, 302 denotes an AC reactor or a transformer, and 303 indicates a capacitor. The reference number 304 designates an AC voltage detector for detecting the voltage of the AC system 20, and 305 indicates an AC current detector for detecting a current of the AC system 20. The reference number 306 designates a DC voltage detector for detecting the voltage of the DC system 30, and 307 indicates a power detection circuit to detect a power based on the voltage and the current detected by both the AC voltage detector 304 and the AC current detector 305. The reference number 308 designates a gate control circuit, 310 indicates a DC voltage control circuit, and 320 denotes a power control circuit. The reference numbers 311 and 321 designate subtracters, 312 and 322 denote compensators, and 330 indicates a selector.
Next, a description will be given of the operation of the conventional power conversion apparatus shown in FIG.9.
The power detection circuit 307 calculates an AC active power P=Vu*Iu+Vv*Iv+Vw*Iw based on each of three phase AC voltage values Vu, Vv, and Vw detected by the voltage detector 304 and each of three-phase AC values Iu, Iv, and Iw detected by the current detector 305. Then, the power detection circuit 307 outputs the calculated AC active power. Where, the reference character "*" designates a multiplication.
The AC active power P is approximately equal to the power that is converted by AC-DC conversion performed by the voltage type power convertor 301. The detected AC active power P is provided to the power control circuit 320. The subtractor 321 then calculates the deviation between the AC active power P and the power reference value Pref. The compensator 322 adjusts the power of the voltage type power convertor 301 according to the calculated the deviation of the power. That is, the compensator 322 increases the power of the voltage type power convertor 301 when the AC active power P detected by the power detector 307 is smaller in magnitude than that of the power reference value Pref. On the contrary, the compensator 322 decreases the power of the voltage type power convertor 301 when the AC active power P detected by the power detector 307 is larger in magnitude than that of the power reference value Pref. Thus, the compensator 322 controls the AC active power P such that P becomes equal in magnitude to the power reference value Pref.
On the other hand, the subtractor 311 calculates the deviation between the DC voltage Vd detected by the DC voltage detector 306 and the DC voltage reference value Vdref. Then, the compensator 312 adjusts the power of the voltage type power convertor 301 according to the calculated deviance of the voltage. Because the power of the voltage type power convertor 301 is adjusted bi-directionally, namely it is increased or decreased, the compensator 312 adjusts to increase the power from the AC to DC when DC voltage is decreased in order to charge the capacitor 303. On the contrary, the compensator 312 adjusts to decrease the power from the DC to AC when DC voltage is increased in order to discharge the capacitor 303. Thus, the compensator 312 adjusts Vd so that the value of the DC voltage Vd equals to the DC voltage reference value Vdref. Thus, both the compensators 312 and 322 adjust the power of the voltage type power convertor 301. In the conventional power conversion apparatus shown in FIG.9, the selector 330 selects the minimum value from the outputs of the compensators 312 and 322, and then one of the DC voltage control circuit 310 and the power control circuit 320 operates according to the selected value.
The gate circuit 308 controls to fire switching elements incorporated in the voltage type power convertor 301 according to the active power instruction Pac and the reactive power instruction Qac.
FIG.10 is a diagram showing a configuration of the voltage type power convertor 301 connected to AC power sources Vi and Vs through an AC reactor. In this case, when a voltage of the AC power source is Vs, a modulation index of the power convertor 301 is k, a reactance of the AC reactor is X, and a phase difference between the AC voltage of the voltage type power convertor 301 and the voltage of the AC power is .phi., it is well known that the active power and the reactive power may be obtained by the following equations: EQU P=k*sin .phi.*Vs.sup.2 /X (1) EQU Q=(k*cos .phi.-1)*Vs.sup.2 /X (2).
The gate circuit decides the timing to turn on and turn off switching elements in the voltage type power convertor 301 based on the modulation index k and the phase difference .phi. according to the equations (1) and (2), and then controls the switching elements in the voltage type power convertor 301. Thereby, the power of the voltage type convertor 301 is adjusted according to the outputs from the compensators 312 and 322 selected by the selector 330.
FIG. 11 is a diagram to explain the operation of the power conversion apparatus shown in FIG.9. In FIG. 11, the horizontal axis designates the AC active power P in which a positive direction from the left to the right indicates a power that is converted from AC to DC. The vertical axis indicates the DC voltage Vd of the voltage type power convertor 301.
The characteristic of the straight line showing a constant level of the voltage in a region shown by P<Pref, as shown in FIG. 11, indicates that the output of the compensator 322 becomes greater according to the amplification of the compensator 322 and then reaches the limit value when the AC active power P detected by the power detection circuit 307 is smaller than the power reference value Pref.
Because the DC voltage Vd is designated near the DC voltage reference value Vdref, and the compensator 312 outputs the value within the output limit value, the selector 330 for selecting the minimum signal value selects the output from the compensator 312 to operate the DC voltage control 310, and the DC voltage of the voltage type power convertor 301 controls Vd so that it reaches the DC voltage reference value Vdref.
When the AC active power P becomes greater than the power reference value Pref, the compensator 322 outputs a small value and the compensator 312 outputs a large value because the DC voltage Vd is smaller than the DC voltage reference value Vdref, so that the selector 330 selects the output of the compensator 322 and then the power control circuit 320 operates. In FIG. 11, a straight line showing a constant value Pref in the region Vd<Vdref indicates this characteristic. Accordingly, in the relationship between the power and the DC voltage in the conventional power conversion apparatus, the DC voltage control circuit 310 operates in one region and the power control circuit 320 operates in other region.
FIG. 12 is a diagram showing the connection configuration of conventional three power conversion apparatuses connected to the DC system. In FIG. 12, the reference numbers 300, 400, and 500 designate power conversion apparatuses, each having the same configuration as the conventional power conversion apparatus shown in FIG. 9. That is, each of the power conversion apparatuses 300, 400, and 500 has the configuration shown in FIG. 9.
In FIG. 12, the reference numbers 201, 211, and 221 indicate AC power sources, each of them is connected to each of the power conversion apparatuses 300, 400, and 500 through each of the AC systems 20, 21, and 22.
FIG. 13 is a diagram to explain the operation of the power conversion apparatuses having the configuration shown in FIG. 12. In FIG. 13, the solid line "a" indicates the power conversion apparatus 300, the dashed line "b" indicates the power conversion apparatus 400, and the dash-dotted line "c" denotes the power conversion apparatus 500.
In the case shown in FIG. 13, the DC voltage reference values Vdref1, Vdref2, and Vdref3 of the power conversion apparatuses 300, 400, and 500 are so set that they have the relationship Vdref1>Vdref2>Vdref3 and the power reference values Pref1, Pref2, and Pref3 are so set that they have the relationship Pref1<Pref2<Pref3.
As shown in FIG. 12, because three power conversion apparatuses 300, 400, and 500 are connected through the DC system 30 to each other, it must be required that they operate so that the sum of the powers of them becomes zero. For example, when the DC voltage is near the DC voltage reference value Vdref1, both the power conversion apparatuses 400 and 500 operate so that the power from AC to DC becomes small in order to decrease the magnitude of the voltage. Thereby, the DC voltage is decreased and the power control circuit 320 in the power conversion apparatus 300 operates.
Similarly, when the DC voltage is near the DC voltage reference value Vdref2, the power conversion apparatus 500 operates so that the power from AC to DC is decreased in order to decrease the DC voltage and the power conversion apparatus 400 operates under its control of the power control circuit.
Thus, when the three power conversion apparatuses having the configuration shown in FIG. 12 has the characteristic shown in FIG. 13, the power conversion apparatus 500 operates so that DC voltage has the DC voltage reference value Vdref3 and its power control circuit operates so that other power conversion apparatuses 300 and 400 have the power reference values Pref1 and Pref2. Accordingly, both the power conversion apparatuses 300 and 400 convert the AC power to the DC power, and the power conversion apparatus 500 converts the DC power, that is equal to the sum of the powers (Pref1+Pref2) of the power conversion apparatuses 300 and 400, to the AC power. The reference characters a', b', and c' designate the operation points of the power conversion apparatuses 300, 400, and 500, respectively.
We will consider the case in which the power conversion apparatuses having the configuration shown in FIG. 12 has the characteristic shown in FIG. 13. For example, because it is difficult to convert the DC power to the AC power when the operation of the power conversion apparatus 500 stops, the DC voltage is increased and the power conversion apparatus 400 operates so that the DC voltage becomes the DC voltage reference value Vref2. At this time, the reference characters a" and b" indicate the operation points of the power conversion apparatuses 300 and 400, respectively. The power control circuit 320 in the power conversion apparatus 300 is operating and the DC voltage control circuit in the power conversion apparatus 400 is operating so that the DC power that is equal to the power reference value Pref1 of the power conversion apparatus 300 is converted to the AC power.
As described above, when a plurality of conventional power conversion apparatuses are connected to the DC system 30, the DC voltage control circuit 110 in one of the power conversion apparatuses operates, and the power control circuits in the remaining power conversion apparatuses operate.
At this time, we will consider the case in which the power control circuit in the power conversion apparatus to convert the DC power to the AC power operates. When the voltage of the DC system 30 is decreased, a current flows so that the DC voltage is decreased in order to keep the power at a constant level. On the contrary, when the voltage of the DC system 30 is increased, the power control circuit 120 operates so that the DC voltage is further increased.
FIG. 14 is a circuit diagram to explain the above operation of the conventional power conversion apparatus. In FIG. 14, the configuration of each power conversion apparatus is the same as that of the power conversion apparatus shown in FIG. 9.
In FIG. 14, in the power conversion apparatus B in the power conversion apparatuses A, B, and C, the DC voltage control circuit of B operates as a voltage source, and the power control circuits in each of the power conversion apparatuses A and C operate as a current source.
When the AC active power P<0 of the power conversion apparatus A is a constant value, the DC current becomes P/Vd. When the voltage Ed of the DC system 30 is decreased based on an accident, for example, the operation of the power conversion C stops, the power conversion apparatus B adjusts the power in order to keep the voltage at a constant level. However, the power conversion apparatus A operates so that the capacitor Ca is discharged (from DC to AC, because P<0) corresponding to the decreasing of the DC voltage. Thereby, the power conversion apparatus B must provide a charging current for the capacitor Ca. But, when the length of the DC system is long, the power conversion apparatus B adjusts the power by using the voltage that is different from the voltage of the capacitor in the power conversion apparatus A. Accordingly, in some cases, deterioration of the control function of the DC voltage happens. Specifically, because it is often caused to increase a phase delay caused by resonance of an inductance component in the DC system and the capacitor of each power conversion apparatus, an underdamped voltage control characteristic is caused. When the distance of the DC system is long, the stability of the system comprising the power conversion apparatuses becomes jeopardized because the difference between the voltage of the capacitor requiring charging and the voltage adjusted by the DC voltage control circuit 110 becomes larger. In addition, when the capacitance of the capacitor C is smaller, the time length of discharging becomes short, the DC voltage control circuit must supply the charging current to the capacitor C. However, because the difference between the voltage of the capacitor requiring charging and the voltage adjusted by the DC voltage control circuit 110 increases, the control characteristic of the DC voltage control circuit 110 becomes undesirable and the degree of the stability of the system is decreased.
Thus, because the conventional power conversion apparatus has the configuration described above, one of a plurality of power conversion apparatuses controls the DC voltage and each of other power conversion apparatuses controls each power. Thereby, the power conversion apparatus to convert the DC power of the DC system 30 to the AC power of the AC system 20 controls so that the current further flows in order to decrease the DC voltage when the DC voltage of the DC system 30 is decreased, and, on the contrary, the DC voltage is further increased when the DC voltage of the DC system 30 is increased. As a result, the DC voltage control characteristic becomes unstable according to the increasing of the distance of the DC system 30 and the decreasing of the capacitance of the capacitor. There is therefore a drawback in the conventional power conversion apparatus that the deterioration of the DC voltage control circuit affects the ability of the AC system because it is difficult to adequately suppress a variation of the DC voltage caused by the resonance in the DC system 30.


A BICMOS input buffer circuit (20) incorporates an integral CMOS passgate circuit (P2,N2) between bipolar input (Q1) and output (Q3,Q4,Q5) transistors of the input buffer circuit. Latch enable inputs (LE) receive latch enable signals for operating the input buffer circuit and internal passgate in a transparent mode for passing data signals from the input (V.sub.IN) to the output (V.sub.OUT) and in a blocking mode for blocking data signals. The internal CMOS passgate circuit (P2,N2) is coupled into the input buffer circuit (20) to control nodes of the transistor output pullup (Q4,Q5) and pulldown (Q3) for controlling the conducting states of the respective transistor output pullup and pulldown to implement the blocking and transparent modes. A third passgate transistor (P3) may also be coupled between a control node (m1) of the transistor output pullup (Q4,Q5) and the low potential power rail (GND) for positive turn off of the output pullup. A dynamic power enhancement circuit (DPC) provides transient enhancement for the transition from the blocking mode to transparent mode.

A conventional buffer circuit configuration 10 is illustrated in FIG. 1. An inverting input buffer circuit 12 coupled between high and low potential power rails V.sub.CCI, GNDI receives input data signals of logic high and low potential levels at the input V.sub.IN. The input buffer circuit 12 drives a passgate circuit PSGT which transmits data signals or blocks transfer of data signals from the passgate input DIN to the passgate output DL depending on the signals at the passgate enable or latch enable inputs LE,LEB. Operation of the conventional passgate circuit PSGT is described below with reference to FIG. 3.
A data signal at the output DL of passgate PSGT is latched by latchback circuit LTBK consisting of feedback coupled inverters IF1, IF2 and provides the input to the final output buffer circuit 14. Output buffer circuit 14 is a tristate output buffer circuit coupled between high and low potential power rails V.sub.CCI,GND0 for driving the final output V.sub.OUT and any load capacitance LOAD. Complementary tristate enable signal inputs OE,OEB are provided to implement the high impedance third state or tristate at the output. Such an output buffer circuit is described for example in U.S. patent application Ser. No. 796,455 referred to above.
The conventional passgate circuit PSGT following the input buffer circuit 12 is shown in further detail in FIG. 3. The passgate circuit is formed by CMOS transistors P1,N1 having primary current paths coupled in parallel. The control gate nodes of parallel coupled CMOS transistors P1,N1 are coupled respectively to complementary latch enable inputs LE,LEB. With complementary signals LE high and LEB low, neither CMOS transistor is conducting and the passgate PSGT is in the blocking mode blocking transfer of data signals from passgate input DIN to passgate output DL. With complementary signals LE low and LEB high, both CMOS transistors P1,N1 are conducting in the transparent mode for transfer of data signals.
A disadvantage of the conventional buffer circuit configuration 10 and passgate PSGT of FIGS. 1 and 3 is that current drive at the output of input buffer circuit 12 is limited by the passgate impedance. The passgate impedance introduces a propagation delay or time shift .DELTA.T for data signals passing from the input DIN to the output DL and limits the edge rate for both the falling and rising edges of the data signals. A conventional approach to overcoming the time shift .DELTA.T is to increase the power of the input buffer circuit 12. This power level may be limited by the circuit specifications however and the problem of undesirable power dissipation also arises.
In order to reduce the impedance of the passgate PSGT, large transistors P1,N1 may be used but this increases the capacitance of the "load" at the output of the input buffer circuit 12. The RC time constant of the passgate continues to adversely effect rising and falling edge rates during transfer of data signals.
A conventional bipolar input buffer circuit 12 is illustrated in further detail in FIG. 2. The example of FIG. 2 is an inverting input buffer circuit delivering low and high potential level output signals at the output V.sub.OUT in response to high and low potential level data signals at the input V.sub.IN. The output pullup and pulldown transistors are bipolar transistors. The Darlington transistor output pullup Q4,Q5 sources current to the output V.sub.OUT from the high potential power rail V.sub.CCI. The bipolar transistor output pulldown Q3 is a high current drive transistor element for sinking current from the output V.sub.OUT to the low potential power rail GND. A bipolar transistor phase splitter Q2 controls the conducting states of the respective output transistor pullup and pulldown in opposite phase in response to data signals at the input V.sub.IN.
The input V.sub.IN is coupled to the base node of phase splitter transistor Q2 through diode D1 for logic low potential level input data signals. For high potential level data signals, the input V.sub.IN turns on input transistor Q1 for providing base drive current through resistors R1 and R2 to the base node of transistor phase splitter Q2. The base node of input transistor Q1 is coupled to the input V.sub.IN through isolating PNP input transistor QP1.
With a high potential level signal at the input V.sub.IN phase splitter transistor Q2 is conducting and turns on the transistor output pulldown Q3. Discharge current passes from the output V.sub.OUT and through discharge paths R5,SD3 and SD2 to accelerate turn off of the transistor output pullup Q4,Q5 and turn on of the transistor output pulldown Q3. The transistor phase splitter Q2 is coupled to the high potential power rail V.sub.CCI through collector resistor R3 and discharges the base and turns off pullup transistor Q4. A low potential level output signal appears at the output V.sub.OUT.
With a low potential level data signal at the input V.sub.IN, the transistor phase splitter Q2 turns off and the base of transistor output pulldown Q3 is discharged through the "poor man" squaring network SD5,R4. An AC Miller killer circuit (ACMK) prevents turn on of the output pulldown transistor Q3 during the transition from low to high potential level at the output V.sub.OUT. The AC Miller killer circuit Q9,SD6,SD4,D2 is coupled to the base node of output pulldown transistor Q3 to divert capacitive feedback Miller current, a parasitic current that may pass from the collector mode to base of Q3 through the internal Schottky diode clamp during charging of output load capacitance and transition from low to high potential level at the output V.sub.OUT. The ACMK discharges the parasitic feedback Miller current to the low potential power rail GND. At the same time the transistor output pullup Q4,Q5 turns on sourcing current and establishes a high potential level output signal at the output V.sub.OUT.
A capacitor coupled transistor CQ6 may be coupled in the discharge path SD1,R7 at the base node of transistor phase splitter Q2 to control the LH edge at the input by slowing down the switching of the phase splitter. It is the output V.sub.OUT of input buffer circuit 12 that drives the passgate PSGT as shown in FIG. 1.

BICMOS input buffer circuit with integral passgate


A method for purging fuel vapors, comprising: purging fuel tank vapors directly from a fuel tank to an engine intake, bypassing a canister, via a venturi, while drawing canister vapors via the venturi into the purged fuel tank vapors en route to the engine intake. In this way, fuel tank vapors may be used to enable purging of a fuel vapor canister, even under conditions where there is insufficient manifold vacuum to enable a canister purge routine. By increasing the frequency of purge opportunities, bleed emissions from a saturated canister may be reduced.

Vehicle emission control systems may be configured to store fuel vapors from fuel tank refueling and diurnal engine operations in a fuel vapor canister, and then purge the stored vapors during a subsequent engine operation. The stored vapors may be routed to engine intake for combustion, further improving fuel economy.
In a typical canister purge operation, a canister purge valve coupled between the engine intake and the fuel canister is opened, allowing for intake manifold vacuum to be applied to the fuel canister. Simultaneously, a canister vent valve coupled between the fuel canister and atmosphere is opened, allowing for fresh air to enter the canister. This configuration facilitates desorption of stored fuel vapors from the adsorbent material in the canister, regenerating the adsorbent material for further fuel vapor adsorption.
However, current and future engine systems may be configured to operate under relatively low manifold vacuum conditions. While this may increase engine efficiency, it also reduces the opportunities for fuel vapor canister purging. This may particularly apply to hybrid vehicles, which have a limited engine run time to begin with. As such, stored vapors may be prone to desorption during diurnal cycles, increasing vehicle emissions and failing to comply with government regulations.
The inventors herein have realized the above issues and have developed systems and methods to at least partially address these issues. In one example, a method for purging fuel vapors, comprising: purging fuel tank vapors directly from a fuel tank to an engine intake, bypassing a canister, via a venturi, while drawing canister vapors via the venturi into the purged fuel tank vapors en route to the engine intake. In this way, fuel tank vapors may be used to enable purging of a fuel vapor canister, even under conditions where there is insufficient manifold vacuum to enable a canister purge routine. By increasing the frequency of purge opportunities, bleed emissions from a saturated canister may be reduced.
In another example, a system for an evaporative emissions system, comprising: a fuel tank coupled to a fuel vapor canister via a first fuel tank isolation valve; an ejector coupled to the fuel vapor canister and a second fuel tank isolation valve, the second fuel tank isolation valve configured to: responsive to a fuel tank pressure being above a threshold, enable fuel vapor to flow from the fuel tank through the ejector to an engine intake; and draw a vacuum on the fuel vapor canister. In this way, the system leverages fuel tank vapor pressure, which currently has no benefits, into generating a vacuum applied to a fuel vapor canister. The vacuum generated by venting fuel tank vapor through the ejector does not add any additional load on the engine.
In yet another example, a method for purging a fuel vapor canister, comprising: during a first condition including a fuel tank pressure above a threshold, close a first fuel tank isolation valve, the first fuel tank isolation valve coupled between a fuel tank and a fuel vapor canister; open a second fuel tank isolation valve, the second fuel tank isolation valve coupled between the fuel tank, the fuel vapor canister, and an engine intake; and open a canister purge valve and canister vent valve. In this way, fuel tank vapors may be purged directly to intake under some conditions, while drawing manifold vacuum is not required to purge the fuel vapor canister. This may lead to an increase in engine efficiency, as a high intake vacuum is not required to purge the fuel vapor canister in order to comply with government regulations for evaporative emissions.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.

System and methods for canister purging with low manifold vacuum


A piston for internal combustion engine, compressor or the like, includes a piston ring, a piston skirt having a piston skirt wall. One or more lubricant channels and reservoirs are provided on an outer surface of the piston skirt. Lubricant is conducted to an outer surface of a piston skirt of a piston through the lubricant channels which are communicating an inner surface of the piston skirt with the outer surface thereof. The lubricant is able to be reserved in the lubricant reservoirs provided on the outer surface of the piston skirt to maintain lubrication between the piston skirt and cylinder wall so as to reduce a friction between the cylinder and the piston skirt, reduce loss of power due to friction and heat, improve the output power, reduce the fuel consuming, noise and exhaust, and achieve fuel saving and environment protection.

1. Field of Invention
This present invention relates to piston structure and more particularly to a piston for internal combustion engine, compressor or the like which is capable of reducing the friction between the piston and the cylinder wall and the method thereof.
2. Description of Related Arts
Piston is the "heart" of an internal combustion engine. It needs to withstand the alternating mechanical and thermal loads. As one of the key components of internal combustion engine it works in the toughest condition. A piston has to keep air pressure and transmit the force to a connecting rod through a pin to rotate a crankshaft. Since the piston works under high temperature, high pressure and high speed condition, it is badly heated but its heat removal effect is relatively low due to its inherent structure. Working under such severe circumstance will cause deformation and more friction, resulting in additional load and stress. It is essential to reserve the performance of bear-resisting, heat balance, alignment, and sealability in order to reduce the friction loss, fuel consumption, noise, and exhaust.
Although piston is always considered to be important during the development of internal combustion engine technique, the column friction loss between piston skirt and cylinder wall can't be sufficiently reduced due to the inherent structure. If the column area between piston skirt and cylinder wall is too small, it can't align the movement steadily; if the column area between piston skirt and cylinder wall is too big, it will increase friction loss. Currently the design of the column area has already been optimized. Since the space between piston skirt and cylinder wall is very small, the failure of forming a lubricant film during high speed movement is the major reason of deformation and heavy wear. As a result, the output power of the internal combustion engine is seriously affected.

Piston for internal combustion engine, compressor or the like


A receiver and method thereof are provided for synchronizing with a global navigation satellite system (GNSS) including a plurality of satellite vehicles (SVs). The method includes starting a verification process and a bitsync (BS) process in parallel with a first SV among the plurality of SVs, and upon completing the verification process while still performing the BS process, starting a track channel process with the first SV based on an interim BS result obtained at the time of completing the verification process, and starting a frame sync (FS) process with first SV based on the interim BS result. An aligned acquisition (AA) process may be started with a second SV among the plurality of SVs, upon completing the verification process, based on the interim BS result.

BS, FS, and AA are some of the processes that a satellite positioning receiver or a GNSS receiver (hereinafter, "receiver") performs in order to synchronize to a reference time of a GNSS constellation and to extract satellite ephemeris and almanac information for positioning and navigation. In weak signal scenarios, a conventional receiver first attempts to extract bit transition boundaries and thereafter, using that extracted information, extend the coherent integration time within the bit boundary to improve received signal to noise ratio (SNR) before starting to look for a sub-frame boundary and perform AA process. Conventionally, the receiver performs a BS process first to identify a bit boundary and then starts FS and AA processes once the bit boundary is known.

Method and apparatus for synchronizing with global navigation satellite system


A communication device includes a receiving unit, a setting storage unit that stores information to represent a source address of a packet to be discarded, a discard determination unit that determines whether a packet received by the receiving unit should be discarded based on the information stored in the setting storage unit, a transmission control unit that discards a packet determined to be discarded and transmits downstream a packet determined not to be discarded, a report unit that reports information on discarding of a packet to a predetermined report destination when the packet is to be discarded, a report history storage unit that stores the source address of the packet as a cause of report when the report unit reports the information, and a report necessity determination unit that determines whether information on discarding of a packet needs to be reported.

In the related art, there is known an IP (Internet Protocol) network as a communication network. As a communication device of such a network, there is known a communication device (such as a router) having a function to discard a predetermined packets among received packets to prevent it from being transmitted downstream (for example, see JP-A-2001-36561).
According to such a communication device having a filtering function, it is possible to prevent an unauthorized access from outside thus enhancing the security in the network.


A method includes selecting upstream and downstream aggregated MAC service data unit (AMSDU) sizes for communications between a client device, an access point, and an controller in a network system. The upstream and downstream AMSDU sizes may be separately selected based on the maximum transmission unit (MTU) size for communications in a secure tunnel between the controller and the access point to avoid fragmentation and reassembly of AMSDUs transmitted in a single MTU. The upstream and downstream AMSDU sizes may be selected to be less or equal to the MTU size.

Over the last decade, there has been a substantial increase in the use and deployment of wireless client devices, from dual-mode smartphones to tablets capable of operating in accordance with a particular Institute of Electrical and Electronics Engineers (IEEE) standard. With "wireless" becoming the de-facto medium for connectivity among users, it has become increasingly important for network systems to intelligently manage connections.
In some systems, wireless client devices may connect with an access point over a wireless connection to transfer and receive data. In upstream communications, the wireless client devices aggregate packets into aggregated MAC service data units (AMSDUs) for transmission to the access point. Similarly, in downstream communications the wireless client devices deaggregate packets transmitted in AMSDUs from the access point.
In some systems, the access point may establish a tunnel with a controller to enable centralized security, thereby eliminating packet tampering in intermediate devices. In transmissions through the tunnel, AMSDUs may be fragmented such that they may be transmitted in maximum transmission units (MTUs). This fragmentation may lead to a reduction of performance for a datapath between the client device, the controller, and the access point as a result of significant processing and delay overhead.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.

Method and apparatus to control TX/RX AMSDU size based on the negotiated maximum transmission unit in the tunnel between a controller and an access point

Hewlett-Packard Development Company, L.P.


A top vacuum corrugation feeder includes articulating suction fingers to assist in raising the top sheet of a stack of sheets to the feedhead of the vacuum corrugation feeder. The suction fingers are rotated down from their interleaved position between feed belts to contact the top sheet in the sheet stack and raises the top sheet to the feed belts. As a result, the feeder can handle heavy sheets, curled sheets, and sheets which are edge welded.

This invention relates generally to a printing machine, and more particularly, concerns an improved copy sheet feeder for such a machine.
High speed xerographic reproduction machines and printers, such as, the Xerox DocuTech.RTM. 135 and Xerox.RTM. 5090 produce copies at a rate in excess of several thousand copies per hour, and therefore, the need for reliable high speed feeding of copy sheets is essential. Presently, some copiers and printers use top vacuum corrugation feeders with a front air knife. In this system, a vacuum plenum with a plurality of friction belts are arranged to run over the vacuum plenum is placed at the top of a stack of sheets in a supply tray. The vacuum system is sized such that there is high open port flow to be able to acquire sheets, but a lower closed port pressure as to not damage or smear the sheets. At the front of the stack, an air knife is used to inject air into the stack to raise the top several sheets from the remainder of the stack. The air pressure actually required to physically separate sheets 1 and 2 from the stack can vary greatly dependent on the basis weight, static conditions, curl conditions, and edge welding properties of the paper. The air knife, however, is designed based on a single air pressure setting for the air knife assembly. This air pressure must be adequate for basis weights from 56 gsm to 200 gsm. This is usually a mutually exclusive event. Therefore, a basic latitude issue arises as to the air pressure requirements for heavy versus lightweight paper. In addition, sheets which are curled in the upward direction, or a stack of sheets with edge welds, present acquisition difficulties. As a result, either the latitude is limited, or a much longer acquisition time is required. A long acquisition time implies that the feed rate is limited. Increasing the vacuum level means that the feeder may cost more and may be noisy. In operation, air is injected by the air knife toward the stack to separate the top sheet, the vacuum pulls the separated sheet up and acquires it. Following acquisition, the belt transport drives the sheet forward off the stack of sheets. In this configuration, separation of the next sheet cannot take place until the top sheet has cleared the stack. In this type of feeding system every operation takes place in succession or serially, and therefore, the feeding of subsequent sheets cannot be started until the feeding of the previous sheet has been completed. In addition, in this type of system, the air knife may cause the second sheet to vibrate independent of the rest of the stack in a manner referred to as "flutter". When the second sheet is in this situation, if it touches the top sheet, it may tend to creep forward slightly with the top sheet. The air knife then may force the second sheet against the first sheet causing a shingle or double feeding of sheets.
Also, some current top and bottom vacuum corrugation feeders utilize a valved vacuum feedhead, e.g., U.S. Pat. No. 4,269,406 which is included herein by reference. At the appropriate time during the feed cycle, the valve is actuated establishing a flow and hence a negative pressure field over the stack top or bottom if a bottom vacuum corrugation feeder is employed. This field causes the movement of the top sheet(s) to the vacuum feedhead where the sheet is then transported to the takeaway rolls. Once the sheet lead edge is under control of the takeaway rolls, the vacuum is shut off. The trail edge of this sheet exiting the feedhead area is the criteria for again activating the vacuum valve for the next feed. While these feeders are successful to some extent in feeding copy sheets at high rates of speed, there is still a need for a more reliable high speed feeder that is lower in cost, lower in noise level, and with increased feeder latitude and reduced shutdown rate than has been practiced heretofore.

Top vacuum corrugation feeder with articulating suction fingers


An exposure apparatus is provided wherein an illumination beam emitted from a mask is projected onto a substrate, through a projection optical system having a reflecting optical element that includes a reflecting region for reflecting the illumination beam at a position spaced from an optical axis of the projection optical system, and a space portion that is provided on the side of the optical axis with respect to the reflecting region. The apparatus further includes a position detecting device for detecting position information of the substrate, at least part of which is located in the space of the reflecting optical element.

1. Field of the Invention
The present invention relates to exposure apparatus and method used in a lithography process for manufacturing, for example, semiconductor devices, liquid crystal displays, plasma displays, thin film magnetic heads, image pickup devices (such as CCD), and photomasks (reticles). In particular, the present invention is concerned with scanning exposure apparatus and method wherein a photomask and substrate are moved relative to each other with respect to an exposure beam.
2. Related Background Art
In a lithography process for manufacturing, for example, semiconductor devices (such as LSI), step-and-repeat type reduction projection exposure apparatuses, or so-called steppers, and step-and-scan type reduction projection exposure apparatuses, or so-called scanning steppers, have been mainly used. In recent years, scanning steppers, which can more easily achieve high-accuracy large-area exposure than steppers, have been dominantly used in order to meet increasing fineness or smaller feature size, and increasing size of semiconductor devices.
In the exposure apparatus as described above, a reduced image of a device pattern is projected onto a wafer through a projection optical system, while alignment marks are detected by an off-axis alignment system located on one side of the projection optical system. Reasons why this alignment system is used will now be explained.
The projection optical system has image-forming characteristics (for example, aberration) that are suitably adjusted according to the wavelength of illumination light for exposure. Where an on-axis type alignment system is employed which detects alignment marks on a wafer via the projection optical system, therefore, the system must use alignment light whose wavelength is close to the exposure wavelength. As the wavelength of the illumination light for exposure gets shorter and shorter, it becomes considerably difficult to select light to which a resist on the wafer is not sensitive, and which causes only small chromatic aberration in the projection optical system. For this reason, the off-axis type alignment system has been increasingly employed which is able to determine the wavelength or width of the alignment light irrespective of the exposure wavelength. In the meantime, an automatic focusing sensor is also provided on one side of the projection optical system.
In a known exposure apparatus, an L-shaped alignment optical system unit with a bent optical axis is disposed at one side of an optical element that is located closest to the wafer in the projection optical system. Thus, the distance between the center of detection of the alignment optical system unit and the position at which a reticle pattern is projected (and which is typically represented by the center of the optical axis of the projection optical system), i.e., the baseline distance, can be reduced as compared with the case where a cylindrical alignment optical system unit with a straight optical axis is provided. The above L-shaped arrangement that can reduce the baseline distance has been generally used for improved stability of the mark detecting accuracy (alignment accuracy) that depends upon the baseline distance.
With the L-shaped arrangement as described above, however, the alignment optical system cannot provide a large numerical aperture (N.A.), thus making it difficult to improve the mark detection accuracy. Namely, in order to improve the resolving power of the exposure apparatus, the N.A. of the projection optical system needs to be increased to, for example, 0.6 or larger, resulting in an increased aperture of the projection optical system. Even if the L-shaped arrangement as described above is employed, it is extremely difficult to locate an objective lens closer to the wafer than mirrors or prisms adapted to bend the optical axis of the alignment optical system. Accordingly, the distance or spacing between the objective lens and the surface of the wafer is increased, and thus the aperture of the objective lens must be increased. It is not easy to produce a large-aperture objective lens with a small aberration, and, even if such a lens is produced, it cannot be positioned without interfering with the projection optical system. Thus, it was inevitable for the known apparatus to use an objective lens with a small N.A.
In order to deal with a wide variety of processes, namely, to improve the mark detection accuracy for each layer, the exposure apparatus as described above includes a plurality of alignment systems of different detection types, for example, FIA (Field Image Alignment) type, LIA (Laser Interferometric Alignment) type, and LSA (Laser Step Alignment) type, as disclosed in U.S. Pat. No. 4,962,318 and U.S. Pat. No. 5,151,750. Where the plural alignment systems are incorporated in a single alignment optical system unit such that at least part of the unit is used in common for these systems, the optical path needs to be diverged or split into a plurality of paths by means of a beam splitter(s). As a result, the structure of the optical system becomes complicated, and the quantity of light of an alignment beam is undesirably reduced, which impedes an improvement of the detecting accuracy. Thus, it has not been easy to satisfy both requirements for dealing with a wide variety of process and improving the detecting accuracy at the same time.
In the meantime, the automatic focus sensor as indicated above includes a light transmitting system and a light receiving system, which are located at respective positions that are spaced from the optical axis of the projection optical system. Accordingly, the relative positional relationship between the light transmitting system and the light receiving system tends to vary due to vibrations, thermal deformation, and the like, and the variations in the positional relationship make it difficult to achieve highly accurate detection, and result in a lack of stability. Also, the automatic focusing sensor is inevitably uses an objective lens having a small N.A. or aperture, for the same reason as described above with respect to the off-axis type alignment system.
Thus, the known exposure apparatus suffers from a lot of problems to be solved for improvement in the accuracy with which the position of the wafer is detected.
It is therefore an object of the present invention to provide exposure apparatus and method that assure improved accuracy with which the position of a substrate is detected, and improved accuracy in overlaying the mask and the substrate. In particular, the present invention aims at providing such exposure method and apparatus that permit highly accurate detection of the position of the substrate, so as to enable the substrate to be exposed with an exposure beam through a projection optical system including a reflecting optical element located close to the image plane of the system. It is another object of the invention to provide a method for manufacturing devices, which method includes steps of detecting the position information of the substrate with high accuracy, and transferring a device pattern on a workpiece.
EUV exposure apparatuses using EUV (Extreme Ultra Violet) light having a wavelength in the range of 5-20 nm, for example, 13.4 nm or 11.5 nm, as exposure light have begun to be developed as exposure apparatuses in the next generation, wherein a circuit pattern whose practical minimum line width (design rule) is about 50 nm to 35 nm is transferred onto a substrate (wafer). In the absence of any optical element that can pass EUV light therethrough, the EUV exposure apparatus is required to use a reflection type reticle, and a reflection type projection optical system consisting solely of reflecting optical elements.
The reflection type projection optical system has an arc shaped illumination region generally called xe2x80x9cring fieldxe2x80x9d, and is characterized in that the optical path of an illumination beam is offset with respect to the optical axis of the projection optical system. If all of the reflecting optical elements that constitute the projection optical system are located coaxially about the optical axis of the projection optical system, therefore, most of the reflecting optical elements include unnecessary regions that are not used for the purpose of reflecting the illumination beam, namely, regions that may be eliminated from the beginning or may be cut out. This is also true with the case of a reflection/refraction type projection optical system including refractive optical elements as part thereof, wherein an optical path of an illumination light beam is offset with respect to the optical axis of the projection optical system.
In a scanning exposure apparatus according to the first aspect of the present invention wherein a pattern of a mask is transferred onto a substrate through a projection optical system while the mask and substrate are moved in synchronism with each other, the projection optical system includes reflecting optical elements as at least part of the system, and at least one of the reflecting optical elements has an exposure-light reflecting region that is located at a position spaced or offset from the optical axis of the projection optical system, while a space including the optical path of exposure light is provided on the side of the optical axis with respect to the reflecting region, and a position detecting device for detecting the position of the substrate is located in at least a part of the space. Thus, the position detecting device can be located close to the optical path of the exposure light, namely, the illumination region. With this arrangement, the distance between an objective optical system of the position detecting device and the substrate can be reduced, thus permitting the use of an objective optical system having a large N.A., which leads to improved accuracy with which the position of the substrate is detected, and improved overlaying accuracy between the mask and the substrate.
In a scanning exposure apparatus according to the second aspect of the present invention wherein a pattern of a mask is transferred onto a substrate through a projection optical system while the mask and substrate are moved in synchronism with each other, the projection optical system includes reflecting optical elements as at least a part of the system, and one of the reflecting optical elements that constitute the projection optical system is located optically closest to the mask and physically closest to the substrate, while a space including the optical path of exposure light is present in a part of the above-indicated one reflecting element or an extended part thereof, and a position detecting device for detecting the position of the substrate is located in at least a part of the space. Thus, the position detecting device can be located close to the optical path of the exposure light, namely, the illumination region. With this arrangement, the distance between an objective optical system of the position detecting device and the substrate can be reduced, thus assuring an improved overlaying accuracy between the mask and the substrate.
In the exposure apparatuses according to the first and second aspects of the invention, where the position detecting device is a mark detecting device (such as an alignment optical system) for detecting marks formed on the substrate, for example, the distance between the center of detection of the mark detecting device and the center of projection of the projection optical system (namely, baseline distance) is remarkably reduced, thus assuring improved stability of the mark detecting device. Also, where the position detecting device is a focal position detecting device (focus sensor) for detecting the position information of the substrate as viewed in the direction parallel to the optical axis of the projection optical system, the length of the optical path of detection light is reduced, thus assuring improved the stability and reducing the size of the focal position detecting device.


Alkaline electrochemical cells with substantially increased performance characteristics have a porous anode, with a porosity equal to or greater than 69%, and a porous cathode, comprising manganese dioxide and having a porosity equal to or greater than 26%.

The present invention relates to alkaline electrochemical cells having porous cathodes comprising manganese dioxide.
Alkaline electrochemical cells have been commercially available for well over twenty years. In many modern applications, alkaline cells vastly outperform traditional zinc carbon cells, and are the batteries of choice for most consumers.
The competition to produce the best alkaline battery continues to be fierce, but a large number of restrictions exist, not least of which is the size of any given cell.
Conventional sizes for primary alkaline batteries include AAA, AA, C, D and 9V (LR03, LR6, LR14, LR20 and 6LR61, respectively), and standard dimensions are laid down for all of these types. Thus, whichever battery is chosen must fit within a given volume, thereby limiting the maximum amount of ingredients which it is possible to put into any given cell.
Working against these constraints, battery manufacturers have, for example, substantially reduced the thickness of the cell walls, reduced the thickness of the seals, and changed the nature of the labelling of the cell, all in order to optimise the use of the internal volume of the cell.
When it becomes impractical to further increase the volume of the cell ingredients, battery manufacturers then have the problem of trying to further enhance performance and battery life through enhancing and/or changing the ingredients used, but there must, ultimately, be a limit.
Another approach to improving battery discharge performance has been to increase the efficiency of active material utilisation during discharge. This is most effective for batteries intended for use under conditions where the discharge efficiency is low (e.g., in devices where the resistive load is low, the current drain is high, or the power consumption is high). This has become increasingly important as battery powered devices tend to place increasingly greater demands on the batteries.
In U.S. Pat. No. 5,283,139 ('139 or US '139 hereafter), there is disclosed a cell in which increased performance is achieved by increasing the density of both the anode and the cathode, without increasing the amount of aqueous, potassium hydroxide electrolyte. If the volume of a given active ingredient cannot be increased, then increasing its density is a logical, straightforward means for increasing the discharge capacity of the cell.
Nevertheless, there remains a desire to provide better and better electrochemical cells.
In International Patent Publication No. WO 01/99214, we demonstrate that, surprisingly, and contrary to expectations, substantial enhancement of cells, above and beyond those prepared in accordance with US '139, is possible, with performances being increased by as much as 15%, or more, by optimising the water ratios, in contrast to US '139.
Prior to '139, U.S. Pat. No. 5,489,493 disclosed alkaline electrochemical cells comprising a cathode comprising manganese dioxide, in which the cathode is composed of a mixture of a minor amount of highly porous manganese dioxide and a major amount of low porosity manganese dioxide. The highly porous manganese dioxide is exemplified as chemical manganese dioxide (CMD) and is distributed throughout the cathode in order to provide ion diffusion paths through the cathode. However, the use of CMD is not desirable in all cases, since CMD has both a lower peroxidation and a lower density than electrolytic manganese dioxide (EMD). Consequently, CMD has a lower theoretical capacity than EMD on a volumetric basis.
In WO 00/30193, there is disclosed the possibility of using a semi-solid cathode material. This semi-solid material has a high porosity and high electrolyte content, and primarily serves to reduce cathode polarisation effects. The drawbacks to this construction include the fact that there is a substantially reduced capacity in the cell and that the MnO2:C ratio is very low but, more importantly, that this cathode material becomes very difficult to handle, so that it is impractical to make a cell containing such material using conventional manufacturing processes and equipment. The capacity and performance of such cells is also severely compromised by comparison with US '139.
WO 98/50969 discloses the use of uniform zinc particles in the anode, which increases performances for anodes having porosities of up to and beyond 80%. Such porosities tend to separate zinc particles and increase impedance, especially in a 1-meter drop test. This disclosure teaches that increased porosities increase performance, provided that there is flaked zinc. High porosities are easily achievable, even at relatively high densities, as zinc is extremely dense, and no upper limit is indicated, although experimental data show good results between 75 and 80% porosity.
Battery industry standards traditionally used constant resistance tests to define battery performance levels for common types of applications. With changes in battery powered devices, together with the availability of more sophisticated testing equipment, there has been a trend to include constant current and, more recently, even constant power tests. There is now an increased importance on achieving improved battery performance on not only heavier loads, but on heavier loads to higher voltage endpoints under both constant current and constant power types of discharge. These trends have also contributed to an increasing need for batteries that perform well in niche areas, such as heavy load, constant current (Amps), constant power (Watts), continuous, and intermittent discharge, and combinations thereof.
Raising battery voltage on discharge can improve the discharge capacity on heavy drain discharge, particularly to higher voltage endpoints. In alkaline batteries, the use of voltage boosting agents such as Ag2O and ferrates is theoretically attractive, but cost, handling, and instability can be problems. Therefore, lowering the internal resistance is the only practical way to increase the operating voltage of the battery. Efforts to increase the electrical conductivity of the anode and cathode as a means of improving discharge performance at high constant wattage have met with little or no success, as the necessary changes in other parameters has counteracted the improvements.
It is well known that dry cell batteries were originally made with mercury, but concern about potential damage to the environment caused by the disposal of large amounts of mercury-containing batteries was substantial. Thus, the amount of mercury contained in dry cell batteries has now been reduced to the extent that, in most consumer batteries on the market, there is no added mercury. There may be traces of mercury present in the zinc, but levels are measured in parts per million.
Reducing the amount of mercury was no easy feat as, apart from anything else, it served to prevent gassing. Removal has proven possible by reducing gassing in other ways, such as improving the purity of the various electrode and electrolyte constituents and by adding various additives, such as substituted ammonium derivatives.
With the elimination of mercury, increasing the levels of zinc also proved necessary, because mercury also contributed to the conductivity of the anode. Removing mercury made the anodic zinc electronically inefficient, and the quantity of zinc had to be increased. To maintain the electrical conductivity at a sufficiently high level throughout discharge, an excess of zinc is generally required. A ratio of zinc capacity to cathode capacity of about 1.33:1 is common. However, the function of the excess zinc is that of a conductor, not an active material, so it limits the amounts of active material that can be put into the battery. An additional disadvantage is that any zinc left after the cell has been exhausted can react with any remaining water to create hydrogen.
The 1.33:1 anode:cathode ratio is common, at least partially, because of the second electron reaction, where MnIII→MnII. This reaction is secondary to the primary reaction in which MnIV→MnIII, but has been considered significant in the total discharge capacity of cells, to date. The second electron reaction takes place in solution at appropriate centres, which tend to be the graphite used for creating conductivity in the cathode. Graphite is not an active material, so the quantity used is generally reduced as far as possible, with a ratio of at least 20:1 active manganese dioxide:graphite being common. Greater ratios of active manganese dioxide:graphite are constantly being sought, in order to maximise the active material, while maintaining conductivity.
However, reducing the quantity of graphite reduces the active centres for conducting the second reaction, so that the second electron reaction becomes inefficient. Accordingly, less of the zinc is consumed, leaving some to gas after cell failure. This effect leads to leakage following deep discharge. Because reducing zinc levels to compensate leads to lower cell discharge capacity, a better option is to ensure that cells will not vent or leak as a result of the typical internal pressures that build up under non-abuse situations.

Optimised alkaline electrochemical cells


An MPEG audio/video decoder has memories, a signal processing unit (SPU) including a multiplier and a butterfly unit, a main CPU, and a memory controller which are time division multiplexed between decoding video and audio data. For audio decoding, the butterfly unit determines combinations of components of a frequency-domain vector to reduce the number of multiplies required to transform to the time domain (matrixing). Matrixing is interwoven with MPEG filtering to increase throughput of the decoder by increasing parallel use of the multiplier, the butterfly unit, and a memory controller.

1. Field of the Invention
This invention relates to decoders for generating audio signals from digital data, and in particular to combined audio and video decoding according to the MPEG standard.
2. Description of Related Art
The Motion Picture Experts Group (MPEG) developed an international standard (sometimes referred to herein as the "MPEG standard") for representation, compression, and decompression of motion pictures and associated audio on digital media. The International Standards Organization (ISO) publication, No. ISO/IEC 11172: 1993 (E), entitled "Coding for Moving Pictures and Associated Audio - for digital storage media at up to about 1.5 Mbit/s," describes the MPEG standard and is incorporated by reference herein in its entirety. The MPEG standard specifies coded digital representations of audio and video and is intended for continuous data transfer from equipment such as compact disks, digital audio tapes, or magnetic hard disks, at rates up to 1.5 Mbits per second.
Under the MPEG standard, parallel data streams or time multiplexed data streams provide video data frames and audio data frames. Methods and systems for decompressing video data frames are described in U.S. patent applications Ser. Nos. 07/890,732, now abandoned, and 07/669,818, now abandoned, which were incorporated by reference above. Audio data frames contain a header, side information, and subband data. Subband data indicate frequency-domain vectors that are converted to time-domain output sound amplitudes by a transformation (matrixing) and a smoothing filter (windowing).
Typically, MPEG audio/video decoding systems for decoding digital data include, two decoders, one for audio decoding and one for video decoding, on two separate integrated circuit chips. The audio decoder and video decoder are separated because of the differences between MPEG audio coding techniques and MPEG video coding techniques, but separate audio and video decoders increase the amount of circuitry in and the cost of an audio/video decoding system. A decoding architecture is needed that reduces the amount of circuitry and the cost of decoding MPEG audio and video data.


A network-based system and method processes and analyzes email messages that have been communicated by parties involved in a legal proceeding. The email messages (or other electronic files) of the parties are delivered to a plurality of server units: metadata of the email messages (such as conversational thread information, directory path information, and other properties information) are directed a first server unit, contents of the email messages are directed to a second server unit, and read-only copies of the email messages are provided in a third server unit. If the email messages (or other electronic files) contain duplicate information, the duplicative email message is linked to an email message that has already been delivered to the server units. Once in the server units, users (such as legal professionals) at terminals on a network communicatively coupled to the server units can formulate and direct queries to the server unit(s) to review copies of the email messages (or other electronic files) that are responsive to the queries.

The legal profession is a profession that requires the review of voluminous amounts of documentation by attorneys. For example, during a document-intensive litigation process known as "discovery," one party (e.g., a "requesting party") frequently requests another party (e.g., a "responding party") to produce documents. The requesting party attempts to build its case by reviewing the requested documents and trying to locate highly significant individual documents (sometimes referred to as "hot documents") that contain text or other information of an incriminating nature.
Document review is an extremely laborious and time-intensive activity. Documents first need to be requested by the requesting party and then produced by the responding party. Litigation strategies dictate that the requesting party try to craft its discovery requests such that the responding party is obligated to produce documents falling within the scope of the requests. Frequently, especially in large litigation cases, discovery requests are drafted very broadly, resulting in the production of thousands of pages of documents, of which only a few pages may be responsive or relevant, if any at all.
The sheer volume of produced documents requires hundreds of hours of attorney and paralegal time to index (e.g., identify and sort each page by a numbering system that uses "Bates numbers") and to review the documents. Frequently, due to the expense of photocopying, only a single set of copies of the produced documents is available to the requesting party, and copies are only made of hot documents when they are located. As such, document review is often characterized by logistic and storage problems, with a group of legal professionals reviewing the produced documents, page by page, in a single room where everyone in the group can have access to the documents. Whenever a hot document is located, that document is typically photocopied or marked (e.g., manually "highlighted" with a highlighter pen, tabbed with a marker, or otherwise identified using manual techniques), and then manually indexed or referenced for later identification and use.
Documents are often produced to the requesting party in random boxes or stacks of pages, and there is virtually no means for efficiently sorting through the stacks and identifying hot documents. That is, other than manually reading each page line by line, it is virtually impossible to sort, organize, or search through the stacks of pages based on criteria such as date, author, recipient, subject matter, etc. Simply stated, document review is a time-consuming and expensive manual process.
With the increased use of network communications in recent years, such as the use of email via the Internet or via a company's internal network, email and other electronic documents are gaining the attention of legal professionals as a rich source of discoverable information. Email is rapidly displacing traditional documents (e.g., letters, contracts, memos, faxes, etc.) as a primary communication medium for business and personal correspondence. Because individuals are more inclined to communicate informally via email, email often contains crucial evidence and is exchanged at a higher rate than traditional documents. Indeed, during the well-publicized case of United States v. Microsoft Corporation, Civil Action No. 98-1233 (TPJ) (D.D.C. Nov. 5, 1999), email correspondence reviewed during the course of discovery was significant in building the United States governments' case against Microsoft. Such cases are becoming more common, where hundreds of thousands of email messages may be involved during litigation.
Although cases such as these are often viewed as "high tech" cases because the subject matter of discovery (e.g., emails or other electronic documents) involves electronic media rather the information printed on paper, these cases are nevertheless constrained to traditional discovery methods. The electronic email documents are downloaded and printed on paper (e.g., "hardcopies"), and then reviewed using the same types of manual reviewing and indexing procedures as used for traditional paper-printed documents. That is, the process involves meticulously analyzing each hardcopy document for specific evidence; indexing/recording which documents have been read, which contain evidence, etc.; and collecting the necessary evidence to develop a legal strategy.
There is virtually no means to control the timing of the discovery critical documents. The pivotal evidence might be discovered at any point during the process of reviewing hardcopy emails, which leaves legal teams with an incomplete picture of the evidence upon which to base their strategy. As is common, the focus or strategy of the litigation may change repeatedly during discovery. Thus, previously reviewed documents that were initially dismissed as irrelevant may need to be repeatedly reviewed. Often, the relevancy of individual documents is difficult to ascertain unless viewed in context along with a large body of documents. Obviously, these problems are aggravated when using traditional manual methods for processing paper documents.
Printing email from its native electronic format into a hardcopy results in the destruction of useful characteristics of email, even if hardcopies are scanned into an imaging database. For example, attachments and nested documents become detached and disassociated from their corresponding email messages. Metadata (e.g., date/time stamps, author identification, attachment data, tracking IDs, headers, etc.) are lost when email is printed.
Conversation threads revealing the contextual relationships between messages are also lost. For example, a response to an email message asking whether or not someone intended to commit an illegal act might be a one-word message simply stating "yes." This reply could be a pivotal in a lawsuit, but if it became disconnected from the email containing the question (as would happen if the email message were printed), the reply would be rendered utterly meaningless. This problem becomes worst if there are multiple cc's, replies, forwards associated with a voluminous number of hardcopy emails. The sheer volume of email hardcopies, coupled with the lack of threading (or other easily identifiable contextual mechanisms), can easily overwhelm readers who, despite their efforts and attention, are nevertheless apt to make mistakes or to miss critical information. Thousands of emails must be read per day, and the emails are often a bewildering combination of disconnected questions and answers, copies of the same message, and detached attachments.
Accordingly, there is a need to improve the manner in which legal documents are made available for review and processing by legal professionals.

Network-based system and method for accessing and processing emails and other electronic legal documents that may include duplicate information


A mounting apparatus is used to mount a fan having a bottom panel with a mounting hole defined therein. The mounting apparatus is configured to support the bottom panel on a top side thereof. The board forms a clip on the top side of the board, and defines a through hole adjacent the clip. The clip includes a elastic shank standing on the top side of the board, a flange formed on a top end of the shank and suspended over the shank, and a driving pole extending downwards from the shank and through the through hole of the board to have a driving end of the driving pole located below the board adapted to bend the shank. The clip is inserted in the mounting hole of the bottom panel with the flange engaging on a top surface of the bottom panel. The bottom panel is sandwiched between the flange and the top side of the board. The driving end of the driving pole is manually bendable to disengage the flange of the clip from the top surface of the bottom panel.

1. Technical Field
The present invention relates to mounting apparatus for fans, and particularly to a mounting apparatus which can conveniently and firmly secure a fan to a computer enclosure.
2. Description of related art
A typical contemporary personal computer includes a central processing unit (CPU) and a power supply. Heat generated by the CPU is removed by a fan attached to the CPU. There is usually a fan in the power supply to assist in cooling the power supply as well.
Components are being mounted in computer enclosures in greater numbers than ever before, and these components not only generate heat in the computer enclosures, but also block air flow, so fans are often installed in the computer enclosures to assist in cooling the computer enclosure. The fans are generally mounted in the computer enclosures by screws, which require using a screwdriver. The attachment procedure is unduly tedious and inconvenient, especially when the enclosure is small. Furthermore, other components in the enclosure are prone to be accidentally damaged during the attachment procedure.
Another conventional means of attachment of a fan to a computer enclosure is to use a fan holder. The fan holder includes four lateral spring hooks and two longitudinal spring hooks. An enclosure defines four lateral and two longitudinal slots therein. The hooks respectively extend through the slots of the enclosure and engage therein. Thus, the fan is fastened to the enclosure. The fan holder does not require screws. However, the fan holder is not easily removed from the enclosure when maintenance or replacement is required.
What is needed, therefore, is an improved mounting apparatus for a fan which solves the above-mentioned problems.

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


An article includes a support substrate bonded to heterostructure epitaxial layers that include one or more electronic devices. The support substrate has a bonding surface and the heterostructure epitaxial layers have a surface with the epitaxial growth direction of the heterostructure epitaxial layers towards the surface. The surface of the heterostructure epitaxial layers is bonded at the bonding surface of the support substrate by ion exchange between the surface of the heterostructure epitaxial layers and the bonding surface of the support substrate.

Monolithically integrating compound semiconductor devices such as laser diodes, light emitting diodes, and heterojunction transistors onto non-native substrates can open the door to many useful applications of these devices. However, most compound semiconductor devices require high quality epitaxially grown layers that can only be attained by crystalline growth on a lattice-matched or lattice-compatible substrate. This substrate restriction severely limits the functionality and application flexibility of many semiconductor devices.

Integration of semiconductor epilayers on non-native substrates


A communication unit for use in a wireless communication system in which a transmitting unit is arranged for wireless communication with at least one receiving unit, said network further comprising at least a first and a second relay node arranged to receive a signal from the transmitting unit and forward it to the receiving unit, said node being characterized in that it comprises a processor arranged to perform the following steps: identifying at least a first and a second communication path between the transmitting unit and the receiving unit, at least one of said paths involving the first or the second relay node, calculating a first and a second capacity of at least one hop in the first and second communication path, respectively communicating information related to the first and second capacity to at least one other communication node in the wireless network.

In the development of wireless/cellular communication networks and systems a good coverage and support of higher data rate, are desired. At the same time, the cost aspect of building and maintaining the system is of great importance and is expected to become even more so in the future. The topology of existing wireless communication systems has traditionally been characterized by the cellular architecture with the fixed radio base stations and the mobile stations as the only transmitting and receiving entities in the networks typically involved in a communication session.
One way to introduce diversity in the received signal is to exploit the spatial diversity offered when multiple antennas are used at the transmitter with the possibility of using one or more antennas at the receiver. The use of multiple antennas offers significant diversity and multiplexing gains relative to single antenna systems. Multiple-Input Multiple-Output (MIMO) wireless systems can thus improve the link reliability and the spectral efficiency relative to Single-Input Single-Output (SISO) system. In wireless systems it is generally not desired to include more than one antenna in the mobile terminals, since they should be kept as small and light as possible.
Another method that offers macro-diversity is relaying. A relaying system is a conventional radio network that is complemented with relay nodes. The relay nodes communicate wirelessly with other network elements, such as a base station, another relay and/or a user terminal. In this way, relay nodes can be used to introduce diversity in a system where one or both of the communicating units only has one antenna. A cooperative relaying system is a relaying system where the information sent to an intended destination is conveyed through various routes and combined at the destination. Each route can consist of one or more hops utilizing the relay nodes. In addition, the destination may receive the direct signal from the source. Cooperative relaying system can be divided into numerous categories based on desired parameters.
P. A. Anghel, G. Leus, M. Kaveh, "Multi-User Space-Time Coding in Cooperative Networks," in Proc. of IEEE ICASSP, Hong-Kong, Apr. 6-10, 2003, and P. A. Anghel, G. Leus, and M. Kaveh, "Distributed Space-Time Coding in Cooperative Networks," In Proc. of the Nordic Signal Processing Symposium, Norway, Oct. 4-7, 2002 discuss relaying schemes based on transmit diversity.
The coherent transmission for cooperating transmitters has been investigated for a regenerative case and with identical transmit powers in Yung-Szu Tu and Gregory Pottie, "Coherent Cooperative Transmission from Multiple Adjacent Antennas To a Distant Stationary Antenna Through AWGN Channels", in Proc. of IEEE VTC 2002, Birmingham, Ala., USA, May 6-9, 2002.
In the literature numerous relaying schemes have been compared to a single hop system in order to a give general recommendation for the suitable scenarios for the deployment of a multi-hop system.
Y. Fan and J. S. Thompson, "On the Outage Capacity of MIMO Multihop Networks", IEEE Globecom 2005, St. Louis, USA, November 2005 discloses a routing algorithm where the decision is based on instantaneous channel state information (CSI). This method has limitations since in practice obtaining the instantaneous CSI is not realistic in an FDD system type.
V. Sreng, H. Yanikomeroglu, and D. D. Falconer, "Relayer Selection Strategies in Cellular Networks With Peer-to-Peer Relaying," IEEE VTC Fall October 2003 discloses a routing algorithm based on the path-gain. A routing algorithm based on the path-gain is not optimal since the fast fading of radio channel is not taken into account in a proper way.

Communication unit and a method in a wireless communication network


A clip for hanging decorative lights from the eaves of a house has an elongated C-shaped body. This body has an intermediate curved section extending between two ends that curve inwardly. A hook is attached to the outside surface of the intermediate curved section. The elongated body is made of a flexible plastic having a memory such that the curved ends may be moved away from one another by a force acting on at least one of the distal ends. When the force is removed the memory will cause the distal ends of the clip to move together. The inward curvature enables the curved ends to unravel to some extent. The combination of the unraveling of the ends and the flexing of the curved intermediate portion enables this clip to fit onto eaves ranging in width from ⅝ inch to over two inches without breaking.

During holiday seasons many homeowners place decorations on and around their houses. One popular way to decorate a house is to attach strings of decorative lights to the edge of the roof or eaves of the house. It has been known to attach decorative light strings by using staples or hooks which are attached to the eaves. This type of attachment creates holes in the wood when the staples or hooks are removed.
Another type of eaves hook involves a generally U-shaped clip which fits over the eaves. One example of such a clip is disclosed in U.S. Pat. No. 3,883,926 to Reynolds. This clip has a flat base containing a hole in which the socket of a decorative light is held. Two arms extend upward from opposite edges of the base and are directed inward toward one another. At the distal end of each arm there is a tab extending outward from the arm. The tabs, arms and base are preferably formed as a single flexible plastic piece, but could be made of metal. A similar Christmas light clip is disclosed in U.S. Pat. No. Des. 306,553 to Ruppel. One disadvantage of this type structure is that the clip can easily be dislodged from the eaves to which it is attached. Another problem is that the shape and flexibility of the arms provide a limited range of widths of boards to which the clip can be attached without slipping or breaking. Clips designed for use on eaves having a width of ⅝ inch should not be used on a 2 inch width unless the height of the arms is relatively long rendering the clip unless on eaves having a height of an inch or less.
Protz, Jr. in U.S. Design Pat. Nos. 368,219 and 385,776 discloses U-shaped clips used to hold Christmas lights on gutters. These clips are similar to that disclosed by Reynolds, but have somewhat different shapes. The distal ends of these clips curve outward with a gradual curvature. Pan in U.S. Pat. No. 5,288,047 discloses yet another clip for holding decorative light bulbs. This clip has two oppositely disposed U-shaped clips in which the outer ends curve outwardly. The disadvantage of this type of clip again is that that the clips can hold onto a fairly narrow range of board or product widths.
The U-shaped clips disclosed by Reynolds and Protz, as well as similarly shaped clips, are typically made of plastic such as polycarbonate. When the arms of these clips are spread apart, stress on the material is concentrated along the joints between the arms and the base. Repeated opening and closing of the arms or opening the arms too wide will cause the clip to break or to weaken along these joints. Such weakening in a clear or translucent polycarbonate clip is often evidenced by a white stress mark.
Consequently, there is a need for a clip for holding decorative lights which will hold securely on eaves of a house and wherein the width of the eaves may range from ⅝ inch to over 2 inches, and the height of the eaves ranges from less than an inch to several inches. These clips should not break or weaken during normal and repeated use.