A novel infant child restraint system that includes a base having a height adjustment to allow the base to assume one of a plurality of positions and inclinations when mounted to the vehicle seat. Additionally, in certain embodiments the base is formed to have a recessed knee-receiving area, into which the user can place their knee when tightening the vehicle's restraint system around the base. The base and car seat are removably attached in interlocking relation using a novel connection mechanism that is not susceptible to premature or improper release due to forces, regardless of the direction of such forces. This mechanism is independent of the car seat handle. Furthermore, this connection mechanism includes a simple manual disconnect or release system, to allow quick removal of the seat from the base.

Infant child restraint systems are well known in the art. Typically, the infant child restraint system is made up of two parts; an infant car seat and a base into which the infant car seat is mounted. The base is positioned on the seat of a vehicle, such as a car, truck, train or airplane, and secured using the restraint system of the vehicle, or a latch system. For example, a base is typically secured in place on an automobile seat through the use of the vehicle's seat belt or a latch system.
The infant car seat is then attached to the base, typically using one or more connection points. This allows the base to be left secured to the vehicle seat, while only the baby seat is removed. To provide maximum protection to the infant, the infant seat is typically oriented such that when the infant occupies the seat, the infant's feet are nearest the seat back.
There are a number of issues associated with each of these two components. For example, as stated above, the base is typically secured to the vehicle seat via the restraint system. Usually the restraint system consists of a lap belt, which in its operative mode is a horizontally disposed belt that passes across the passenger at the waist. The restraint system also includes a shoulder belt, which in its operative mode is slanted and positioned from the waist of the passenger on one side to the opposite shoulder. Alternatively, a latch system can be employed.
In view of its low vertical profile, the base generally must be secured using only the lap and shoulder belt. Given the single axis of restraint, it is important that the weight of the base (with the baby seat) is properly distributed. If the belt crosses the base at an unstable position, it is possible that the base may be able to rotate about this axis of restraint, especially in the case of a sudden change in motion, such as sudden braking or a crash impact.
A second issue associated with the base is the need to insure that the base is tightly secured by the vehicle's restraint system. If the belt is not taut, it is possible that the base (and attached baby seat) can shift forward during a sudden stop or crash impact.
Another issue is the variation in slope and position of the vehicle seat onto which the base is placed. For example, some vehicle seats are horizontal, or nearly horizontal. Others, however, are much more sloped. Typically, the inner portion of the seat, where it meets the seat back, will be at a lower height then the outer portion of the seat, where the user's legs hang from. Therefore, the base, unless it has an adjustment, is positioned at different inclinations, based on the vehicle's seat. These differences in inclination cause the infant car seat to also be at different inclinations; some of which may not offer sufficient protection for the infant. Height adjustments within the base can be used to minimize this issue.
In addition to the above mentioned safety concerns associated with the base, there are also a number associated with the connection of the base to the infant car seat. The connection of the base to the infant car seat has conflicting goals. On the one hand, it is preferable for the seat to be easily disconnected from the base, so that a parent can easily separate the infant car seat from the base and use the disconnected seat as a baby-carrying apparatus. On the other hand, it is imperative that the connection be robust enough that it does not inadvertently disconnect in response to a sudden motion or impact.
Therefore, it is important that the connection mechanism between the base and the infant car seat be easily actuated yet robust, even in the presence of sudden, unexpected movements. Some connection mechanisms are optimized to withstand forces in one particular direction. In other words, they are tested to insure no inadvertent disconnections when the seat is forced forward relative to the base. While this is obviously important, this connection must equally withstand forces that tend to push the infant car seat backward, to the left and to the right.
While the strength of the connection cannot be compromised, there is a need for a manual disconnect mechanism that is preferably simple and requires little force to operate. This manual disconnect mechanism is preferably operable using a single hand, such that the other hand can be used to hold or support the infant car seat. Additionally, the mechanism should preferably be located in a convenient location, so that the user can readily access the mechanism with minimum inconvenience.
In addition to the strength and convenience of the connection mechanism, another important consideration is the location of the mechanism with respect to both the base and the car seat. In some embodiments of the prior art, the connection mechanism includes one point of attachment. In this scenario, the location of that attachment point is critical. If the attachment point is located near one end of the car seat, such as near the feet, it may be possible for the car seat to rotate about this attachment point. For example, a sudden stop may cause the car seat to move relative to the base. If the attachment point is located near the end of the car seat (either the head end or the foot end), the seat can rotate about this point, causing unnecessary motion of the seat and excessive stress on the attachment point and connection mechanism.
Some other considerations include the overall weight and strength of the infant car seat, and its ability to be attached to a stroller, or other apparatus.
Currently, some of these issues are addressed in a variety of ways, with varying degrees of success. In some cases, the solutions to these issues are expensive, thereby raising the price of the infant child restraint system. It would be beneficial if these issues could be addressed in a safe, convenient and cost effective manner.


Disclosed is an encapsulating material for solar cell containing an ethylene/α-olefin copolymer satisfying the following requirements (a1) to (a4): (a1) the content ratio of structural units derived from ethylene is from 80 to 90 mol % and the content ratio of structural units derived from α-olefin having 3 to 20 carbon atoms is from 10 to 20 mol %; (a2) MFR is from 10 to 50 g/10 minutes as measured under the conditions of a temperature of 190 degrees centigrade and a load of 2.16 kg in accordance with ASTM D1238; (a3) the density is from 0.865 to 0.884 g/cm3 as measured in accordance with ASTM D1505; and (a4) the shore A hardness is from 60 to 85 as measured in accordance with ASTM D2240.

With growing concerns about global environmental issues and energy issues, a solar cell has been paid attention as an energy generating means. Such energy is clean with no concerns about drying up. When a solar cell is used in outdoor environment such as on the roof of a building, it is generally used in the form of a solar cell module.
The aforementioned solar cell module is generally produced according to the following procedures. First, a crystalline solar cell element (hereinafter also referred to as the power generating element or cell, meaning the same) formed from polycrystalline silicon, monocrystalline silicon or the like, or a thin film solar cell element obtained by forming an ultra-thin (several micrometers) film made of amorphous silicon or crystalline silicon onto a substrate of glass or the like, is manufactured. Next, in order to obtain a crystalline solar cell module, a protective sheet for a solar cell module (surface protective sheet), an encapsulating material sheet for solar cell, a crystalline solar cell element, an encapsulating material sheet for solar cell and a protective sheet for a solar cell module (back surface protective sheet) are laminated in this order. On the other hand, in order to obtain a thin film solar cell module, a thin film solar cell element, an encapsulating material sheet for solar cell and a protective sheet for a solar cell module (back surface protective sheet) are laminated in this order. Thereafter, a solar cell module is manufactured through a lamination method in which the laminated material is absorbed under vacuum and pressed with heating. Solar cell modules manufactured in this manner are weather-resistant and thus are suitable for use in outdoor environment such as on the roof of a building.
As an encapsulating film material for a solar cell, a film made of an ethylene/vinyl acetate (EVA) copolymer has been widely used because it is excellent in transparency, flexibility and adhesiveness. For example, Patent Document 1 discloses an encapsulating film excellent in both adhesiveness and film-forming properties consisting of a crosslinking agent and an EVA composition containing trimellitate. However, when the EVA composition is used as a constituent material of an encapsulating material for solar cell, there is the risk of possibly affecting the solar cell element by the component such as acetic acid gas and other unwanted gas generated by decomposition of EVA.
On the other hand, there has been proposed the use of a polyolefin based material, particularly an ethylene based material, as an encapsulating film material, because it is also excellent in insulation properties (for example, see Patent Document 2).
Meanwhile, there has also been proposed a resin composition for an encapsulating material for solar cell using an ethylene/α-olefin copolymer excellent in a balance between rigidity and crosslinking properties, and extrusion moldability (for example, see Patent Document 3).

Encapsulating material for solar cell and solar cell module


A system for projecting content at an angle to a rear projection screen. The system includes a projector configured for projecting changeable electronic content and a rear projection screen for receiving the projected content at an angle and displaying the projected content. The rear projection screen includes a turning film having prisms facing toward or away from the projector. For prisms facing toward the projector, a protective film covers the turning film. When the projected content is displayed on the rear projection screen, the content has a substantially uniform appearance.

Rear projection films are increasingly used in digital point of purchase signage. One of the challenges with using these rear projection films in point of purchase applications relates to the long throw distance of most projectors, typically measuring two to three times the long axis of the display. The expansion angle of the image emanating from the projector increases dramatically when the throw distance is shortened. When the entrance angle of the image projected onto the rear projection screen is increased, the light capture efficiency of the screen decreases rapidly. This phenomenon results in significant uniformity and view angle loss, and it can lead to an observable hot spot in the center of the image, which moves around as the viewer changes position, leading to poor useful view angle. Accordingly, a need exists for an improved rear projection screen, particularly for digital signage.


A method and system for determining sequence parameters to limit cycle attack in time-line sequences associated with digital signature technologies is disclosed. The method comprises the steps of determining a pair of values associated with a modulus value for generating said sequence, wherein said values are non-equal prime numbers of a known size, selecting a root value of said sequence and selecting a third value for determining the order of said sequence. In one aspect of the invention, each of the pair of values used to determine the modulus is a safe prime number.

In the field of electronic commercial transactions, a guarantee that a certain operation will take a minimum amount of "time," understood here as a number of computational steps, enables a variety of electronic commerce applications, for example, the timed release of a payment (e.g., a mortgage payment), and/or the fair exchange of information items such as a digital signature. This guarantee is particularly important between the exchange of two parties, i.e., a committing party and a receiving party, when there are no trusted parties acting as intermediaries. In this case, the guarantee insures that either both parties obtain each other's commitment information or neither party obtains the other's commitment information. When both parties receive each other's commitment information substantially concurrently, then electronic contract signing may be completed by the transfer of each party's digital signature. However, when contract negotiations are abruptly terminated for failures, either intentional or unintentional, that may occur in the transmission, one party may obtain a significant advantage over the other party by the failure to complete the communication.
A leading candidate operation for preventing one party from obtaining a significant advantage over the other party is the use of modular exponentiation in the commitment information. Modular exponentiation is a well-researched operation believed not well suited for parallelization, i.e., operations by multiple computers or computing systems substantially concurrently. Indeed, timed sequences based on modular exponentiation, where the next element in the sequence is obtained from raising the previous element to a certain power, has been taught in Rivest, et al., "Time-lock Puzzles and Timed-Release Crypto," MIT/LCS/TR-683, 1996. Rivest teaches the construction of "time-lock puzzles" for encrypting data, where the goal is to design puzzles that are "intrinsically sequential." In using time-lock puzzles, putting computers to work together in parallel does not speed up the finding a solution to the puzzle. Using a function similar to that of Rivest, Boneh and Naor (See, D. Boneh and M. Naor, "Timed Commitments (extended abstract)," Advances in Cryptology, CRYPTO 2000, volume 1880 of Lecture Notes in Computer Science, pages 236-254, Springer-Verlag, 2000) defined the notion of verifiable timed commitments as an extension to the standard notion of commitments in which a potential forced opening phase permits the receiving party to recover, with significant effort, the committed value without the help of the committing party. Boneh and Naor show how to use timed commitments to realize a variety of applications involving time, including timed signatures of a special kind, and, in particular, contract signing. Boneh and Naor also show how to exchange Rabin and RSA signatures when the respective moduli coincide with the one used to build the timed sequence.
Efficient Boneh and Naor time structure generation is proposed by Garay and Jakobsson (see, Garay and Jakobsson "Timed Release of Standard Digital Signatures," Proceedings of Financial Cryptography '02, Matt Blaze (Ed.), volume 2357 of Lecture Notes in Computer Science, pages 168-182, Springer-Verlag, 2002). Garay and Jakobsson teach how to generate, and use, time structures or time-lines together with blinding techniques for the timed release of standard signatures.
A further improvement in the construction of time-line based on modular exponentiation, referred to as a "mirrored time-line," is more fully disclosed in the concurrently-filed, co-pending related patent application Ser. No. 10/611,711, filed Jun. 30, 2003, entitled "Method and System for Fair Exchange of User Information" and in Garay and Pomerance, "Timed Fair Exchange of Standard Signatures," Financial Cryptography '03, Rebecca Wright (Ed.), LNCS, Springer-Verlag (to appear), Gosier, Guadeloupe, January 2003. In this improved time-line construction, a protocol is disclosed that allows for the fair exchange of standard signatures, and further enables each receiving party to recover, with limited effort, the committed value without the help of the committing party.
An important requirement in the time structures discussed above is that the underlying sequence that comprises the structure does not cycle. That is, the period of the sequence is large enough that there are no repeated values in the sequence. Otherwise with a sequence that repeats, no guarantees could be given that a time-line would be traversed sequentially. That is if a repeated value is observed in the sequence, then the party computing the sequence can skip intermediate values and jump ahead to the next repetition(s). Such operations, referred to as cycle attacks, are known to be are possible when the sequence period is shorter than the total number of elements in the sequence.
Efforts have been made in estimating the period of more general sequences of the form gab for arbitrary g, a and b. See for example, Friedlander, et al., "Period of the Power Generator and Small Values of Carmichael's Function," Math. Comp. 70 (2001), pp. 1591-1605 and Friedlander, et al.,"Small Values of the Carmichael Function and Cryptographic Applications," Progress in Computer Science and Applied Logic, Vol. 20, pp. 25-232, Birkhäuser Verlag, Basel Switzerland, 2001. However, the period of sequences used in association with a timed release, timed commitment, timed fair exchange or "mirrored-time-line" has not been considered before.
Accordingly, there is a need for a method and system that allows for the selection of parameters that construct time-line sequences having periods that are large enough to limit cycle attacks on the time-line.

Method and system for determining sequence parameters to limit cycle attacks in timed release cryptography


A signature feeder/conveyor for converting tightly packed signatures into a succession of discrete signatures stacked on edge while moving the signatures while on edge to an end station for delivery thereto upon demand. The feeder/conveyor involves successive stages of walking the signatures on edge in steps to compact the stream of signatures, then loosen the stream, and then substantially sliding the loosened signatures on edge without walking for delivery to the end station. A sensor detects the pressure of loosened signatures approaching the end station for controlling the successive stages of walking the signatures.

In the graphic arts industry, signatures (which are sheets oftentimes folded into a "V") are required to be assembled and then bound in book form by a saddle stitcher such as disclosed in McCain U.S. Pat. No 3,087,721. The different signatures are first stacked into tightly packed logs and supplied to respective feeder conveyor stations. The individual signatures are separated from the log and fed to a gathering mechanism such as a chain, moving past the stations, one signature being dropped atop another. Several stations may be involved, each feeding a different signature for one book, or there may be only two active stations. Equipment associated with these stations maybe controlled in many ways: McCain U.S. Pat. Nos. 3,565,422, 3,589,712 and 3,608,893.
Signature machines may be located in a bindery area near the press room, or in an adjacent building. The printed matter, fresh from the press, is bundled into logs and delivered by pallets, or the like, to feeder stations where an attendant takes over. The function of the attendant is to keep the supply stations full with makeup additions. Heretofore, this involves the attendant separating a small stack of signatures from the log, carrying it to the feeder/conveyor and placing it there for manipulation. It is also necessary that the signatures be joggled by the attendant so they will not stick together as a result of friction, static electricity, etc. Even the best worker can get behind or err when separating, carrying and loosening the stacked signatures as an incident to assuring proper feeding of the signature on the feeder/conveyor. Quite often this human error has resulted in human injury, machine stoppage, signature jamming, etc.


Systems and methods for envelope-based acoustic echo cancellation in a communication device are provided. In exemplary embodiments, a primary acoustic signal is received via a microphone of the communication device, and a far-end signal is received via a receiver. Frequency analysis is performed on the primary acoustic signal and the far-end acoustic signal to obtain frequency sub-bands. An echo gain mask based on magnitude envelopes of the primary and far-end acoustic signals for each frequency sub-band is generated. A noise gain mask based on at least the primary acoustic signal for each frequency sub-band may also be generated. A combination of the echo gain mask and noise gain mask may then be applied to the primary acoustic signal to generate a masked signal. The masked signal is then output.

1. Field of Invention
The present invention relates generally to audio processing and, more particularly, to envelope-based acoustic echo cancellation in an audio system.
2. Description of Related Art
Conventionally, when audio from a far-end environment is presented through a speaker of a near-end communication device, sounds from a far-end audio signal may be picked up by microphones or other audio sensors of the near-end communication device. As such, the sounds from the far-end audio signal may be sent back to the far-end environment resulting in an echo to a far-end listener.
Conventionally, acoustic echo cancellation (AEC) systems may take the far-end audio signal and use it to predict the echo of the far-end audio signal (after being played through the speaker and picked up by the microphone). Typically, a transfer function that describes a path from the far-end audio signal, through the speaker, through an acoustic environment, and back to the microphone is linearly modeled to predict the echo. These AEC systems are performed in a waveform domain whereby the echo is predicted, inverted, delayed, and subtracted out from a near-end audio signal.
Disadvantageously, there are many problems with these conventional AEC systems. First, the transfer function (i.e., relationship between the far-end audio signal and the echo) is typically constantly changing, since the acoustic environment is rarely fixed. In the case of a handheld communication device (e.g., a cellular phone), there may also be reflections off a face of a user. The prior art AEC systems are adaptive and continually update the transfer function. However, errors usually occur in the echo prediction due to the changing environment. If the echo prediction is even slightly incorrect, or an applied delay is incorrect, residual echo will remain.
A second disadvantage is that these prior art AEC systems typically use a linear model (i.e., linear filter) to predict the echo. However, the transfer function is often not linear (e.g., if there are non-linearities in the speaker which may cause distortion). As a result, poor echo prediction may occur.
Other AEC systems may attempt to overcome this disadvantage by introducing non-linearity to the echo prediction model. However, this results in more complexity. For example, non-linearity may become problematic in cellular phones or speakerphones with cheap components. The prediction may be difficult to obtain unless an exact model of the speaker (e.g., of the cellular phone or speakerphone) is known.

System and method for envelope-based acoustic echo cancellation


Described is a system for configuring a wireless mobile device for operation on a wireless network including a receiving element to receive configuration information for the wireless device and a generation element to generate codes for an optically readable element, the optically readable element configured to be read by the wireless device, wherein the configuration information configures the wireless device for operation on a wireless network.

When a mobile unit ("MU") is added to a network, it must first be configured with parameters compatible with the network. The configuration process may include inputting network identifications and various passwords and/or security codes. An MU new to the network may also lack the latest updates and programs, requiring their download and installation before the MU is fully functional on the network.
Currently, a user of the MU manually enters all the necessary configuration information and downloads and installs all the required files. Whether this process is outsourced or executed internally, it is an additional task and cost that delays deployment of the MUs. Businesses that employ enterprise mobility solutions today typically have several thousand MUs connected to their network at one time. As the size of these networks grow, the costs and time associated with device roll-out increases exponentially. Moreover, a business with multiple facilities or networks may require that an MU be frequently transported between and reconfigured for different networks. Therefore, there is a need to expedite the cumbersome roll-out process so that new MUs are ready to connect to the network and perform their required operations with minimal time and effort.

System and method for rapid deployment of a wireless device


A manufacture method of a non-spherical lens module includes: firstly, forming a housing having a row of through holes running through a first surface and a second surface thereof; secondly, providing and filling liquid waveguide with the through holes and forming two convex portions at jointing positions of the through holes and said two surfaces respectively; lastly, cooling the liquid waveguide to form the waveguide in the through hole, cooling the two convex portions to form first and second lens portions.

1. Field of the Invention
The present invention generally relates to a non-spherical lens module, and more particularly, to a novel structure of a non-spherical lens module for easy manufactory and achieving cost-down purpose.
2. Description of Related Art
Signal transmitting by cables has been widely applied in industry. Now there is a new technology of signal transmitting by optical-fiber for speeding up signal transmission. Therefore, many companies all develop optical-fiber transmission technology. In particularly, the Intel Company has released Light Peak Technology on internet which includes a connector with an optical-fiber at back of the connector. Signal is transmitted by the optical-fiber to other connector. Our company intends to design an optical-fiber connector for easy manufactory and achieving cost-down purpose. Our company also design a lens module used in conjunction with the optical-fiber. Thus, a lens module for easy manufactory is desired to achieve cost-down purpose.
Hence, the present invention is directed to solving this problem in the related art.

Non-spherical lens module for easy manufactory


A method of controlling an atomic oscillator includes generating a resonant light pair in response to a center frequency signal and a sideband signal, and setting the sideband signal so that an electromagnetically induced transparency (EIT) phenomenon does not occur in a gas cell of the atomic oscillator. The method includes applying the resonant light pair to the gas cell and detecting an intensity level of light transmitted through the gas cell. While the sideband signal is set so that the EIT phenomenon is not occurring, the center frequency signal is varied until a minimum value of the intensity level is identified. A first frequency is calculated by subtracting a predetermined frequency offset from the center frequency at which the intensity level was equal to the minimum value. A center frequency of the resonant light pair is set to the first frequency for operation of the atomic oscillator.

1. Technical Field
The present invention relates to an atomic oscillator, and particularly to a technique to generate an optimum frequency of EIT to maximize EIT intensity in an atomic oscillator of an EIT system.
2. Related Art
An atomic oscillator based on an electromagnetically induced transparency system (EIT system, also called a CPT system) is an oscillator using a phenomenon (EIT phenomenon) in which when two resonant lights different from each other in wavelength are simultaneously irradiated to an alkali metal atom, the absorption of the two resonant lights is stopped. Only one pair of two resonant lights different in wavelength is prepared, and the frequency is controlled so that the frequency difference (wavelength difference) between the two simultaneously irradiated resonant lights accurately coincides with an energy difference ΔE12 between the respective ground levels. An initial operation at the time when the atomic oscillator in a stop state is started will be described. When the power source of the atomic oscillator is turned on, first, a wavelength of a light source is swept to find the bottom of an absorption band of an objective alkali metal atom. That is, the minimum value of a detection signal is detected when the center frequency of a resonant light pair is swept, that point is determined to be an excitation frequency (excitation wavelength), and an EIT signal is obtained.
U.S. Pat. No. 6,265,945 (patent document 1) discloses a structure and an operation method of a CPT system small atomic oscillator of a sideband system in which a surface emitting laser (VCSEL) is used as a light source.
However, it is experimentally confirmed that the excitation frequency (excitation wavelength) at which the maximum EIT signal intensity is obtained is not the bottom of the absorption band and is shifted to a low frequency side from the bottom of the absorption band (FIG. 4 shows a case where the alkali metal atom is a cesium (Cs) atom, and the EIT signal intensity is maximum at the frequency of point P. The bottom of the absorption band is near 500 (MHz) in the value of the horizontal axis of the drawing. Incidentally, the reference (zero point) of the absolute value of the horizontal axis is arbitrary.). Thus, in the related art atomic oscillator, it can not be necessarily said that the maximum EIT signal is detected, and the degradation of S/N is caused.
Besides, in the related art disclosed in the patent document 1, the frequency condition of two light waves to maximize the CPT (EIT) signal intensity is not prescribed.

This patent is subject to a terminal disclaimer.

Atomic oscillator and control method of atomic oscillator


A mine explosion-isolating hoisting device with a built-in type permanent magnet motor includes a spindle fixed on the ground; a permanent magnet motor stator fixed on the spindle; a drum rotating relative to the spindle, the drum surrounding the spindle circumferentially; and a permanent magnet motor external rotor fixed by a spoke plate and rotating relative to the spindle; the drum is connected to the permanent magnet motor external rotor via an isolating disc; and a radial distance between an outer circumferential surface of the permanent magnet motor external rotor and an inner wall of the drum is greater than a preset value.

A mine explosion-isolating winch is applied to flammable and combustible special working environments with a high gas and the like such as a shaft of a coal mine, a metal mine, and a non-metal mine, and configured to hoist a material or a person, etc. However, the existing explosion-isolating hydraulic winch and the traditional explosion-isolating three-phase asynchronous motor and decelerator type winch have the defects that the failure rate is high, the reliability is not high and the operation is also not stable enough due to a large load and an evil service environment.

Mine explosion-isolating hoisting device with built-in type permanent magnet motor

Guiyang Plateau Machinery Company Limited


A clock adjustment circuit includes: first and third switching elements to be in a conductive state when in-phase and reverse-phase clock signals in a high level are applied to input terminals, respectively; second and fourth switching elements whose input terminals are connected to output terminals of the first and third switching elements, respectively, which become in the conductive state when the in-phase and reverse-phase clock signals in a low level are applied to output terminal, respectively; first and second capacitor elements whose one terminal is connected to an output terminal of the first and third switching element, respectively; and a shift detection unit detecting potential difference between the output terminals of the first and third switching elements and outputs the detection signal as a signal for adjusting a duty ratio of the clock signal.

1. Field of the Invention
The present invention relates to a clock adjust circuit, a shift detection circuit, an imaging device and a clock adjustment method capable of detecting and adjusting a shift in a duty ratio of a clock signal.
2. Description of the Related Art
Clock signals are heretofore used for controlling operations in various electronic apparatuses. For example, clock signals are supplied also to circuits such as a counter and a DAC (Digital to Analog Converter) in solid-state imaging devices such as a CIS (Contact Image Sensor) (for example, refer to JP-A-2005-323331 (Patent Document 1)).
Here, FIG. 15 shows a circuit block configuration on the periphery of the counter used in the related-art solid-state imaging device, for example, proposed in Patent Document 1. In the related-art solid-state imaging device, a clock signal (internal clock) having a given duty ratio generated by a clock generation unit 201 is supplied to a DAC 203 and a counter 204 through a buffer 202. In such solid-state imaging device, the counter 204 is driven by a DDR (Double Data Rate) system to generate a high-definition as well as high-frame rate video signal.
The operation outline performed when the counter 204 is driven by the DDR system will be explained reference to FIG. 16. FIG. 16 is a schematic block configuration diagram of the DDR-driven counter 204. The DDR-driven counter 204 includes a first latch 205 and a second latch 206. The clock signal (CLK in FIG. 16) is inputted to one input terminal of the first latch 205 and a data signal (Data in FIG. 16) is inputted to the other input terminal. Additionally, the clock signal is inputted to one input terminal of the second latch 206 through a NOT element 207 (inverter) and the data signal is inputted to the other input terminal.
When the counter 204 is DDR-driven, counting processing is performed at both timings of rising and falling of the clock signal to be inputted. Specifically, the first latch 205 latches data when triggered by rising of the clock signal, and the second latch 206 latches data when triggered by falling of the clock signal. Then, the data latched by the second latch 206 is used as the least significant bit of the counter 204.
In the counter 204 having the above configuration, a trigger cycle in which data is latched by the first latch 205 and the second latch 206 is desired to be half of the cycle of the clock signal. That is, the duty ratio of the clock signal at the time of driving the counter 204 in the DDR system is ideally desired to be 50%.
In the present specification, "duty ratio" of the clock signal means the ratio of a high-level period occupied in one cycle of the clock signal, which can be calculated by [H-width/clock signal cycle]×100%. Hereinafter, the high-level period and a low-level period of the clock signal are referred to as an H-period and an L-period and values of the time width of the H-period and the L-period are referred to as an H-width and an L-width.

Clock adjustment circuit, shift detection circuit of duty ratio, imaging device and clock adjustment method


A vehicle includes an accelerator pedal moveable across a plurality of predefined positions and a controller programmed to, responsive to the pedal reaching a tip-in position, command a downshift to a downshift gear from an initial gear. A difference between the initial and downshift gears exceeds a number of predefined positions crossed upon moving to the tip-in position when a rate of change of pedal position exceeds a predefined threshold.

Downshift scheduling for automatic transmissions may be based on gear and pedal position. A downshift scheduling plot may illustrate a relationship between vehicle speed and a driver demand for torque, the latter being indicated by an accelerator pedal position. If the pedal spacing between shift points on the plot are too close together, a driver may tip-in and back out of the pedal to hunt for the desired gear to meet driver demand.


The present invention relates to a method for preparing graphene using the two-dimensional confined space between the layers of inorganic layered materials. Such method comprises the following steps: mix a soluble salt of a divalent metal ion M2+, a soluble salt of a trivalent metal ion M′3+, a soluble salt of a chain alkyl anion A− and a carbon source molecule C and dissolve them in deionized and CO2-eliminated water to prepare a mixed salt solution; mix the mixed salt solution with an alkali solution under nitrogen protection and subject them to reaction and crystallization under nitrogen, and filter the suspension obtained thereafter and wash the filter cake with deionized water until the pH of the filtrate is 7 to 7.5, and then dry the filter cake to obtain layered double hydroxides with an intercalated structure; under an inert atmosphere or a reducing atmosphere, calcinate the layered double hydroxides with an intercalated structure to provide a calcinated product; add the calcinated product into a hydrochloric acid solution for ultrasonic treatment, and separate the solution by centrifugation and wash the precipitate obtained by centrifugation with deionized water until the pH of the filtrate is 6.5 to 7 to obtain the graphene.

Graphene is a two-dimensional (2D) carbon nanomaterial in which the arrangement of carbon atoms is identical to that in a single atomic layer of graphite, and generally refers to a 2D carbon layered structure stacked with less than 10 carbon atom layers. Since the number of layers of graphene has direct impact on the distribution of the electron cloud thereof, graphenes with various number of layers have different optical and electric performances, and the controlled synthesis of graphenes with various number of layers is beneficial in practical applications.
Novoselov et al. (K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva and A. A. Firsov, Electric field effect in atomically thin carbon films, Science, 2004, 306: 666-669) employed a mechanical peeling method to peel single-layer and multi-layer graphene thin films from highly oriented pyrolytic graphene and observe them, but such preparation method is difficult to control and scale up; Kim et al. (K. S. Kim, Y. Zhao, H. Jang, S. Y. Lee, J. M. Kim, K. S. Kim, J.-H. Ahn, P. Kim, J.-Y. Choi and B. H. Hong, Large-scale pattern growth of graphene films for stretchable transparent electrodes, Nature, 2009, 457: 706-710) utilized a chemical vapor deposition method to deposit various number of layers of graphene on a nickle substrate using methane as the carbon source, but such method used a gaseous carbon source which might cause safety issues during storage and in the process of reaction and could not produce graphene in large scale. Zhang et al. (W. Zhang, J. Cui, C. Tao, Y. Wu, Z. Li, L. Ma, Y. Wen and G. Li, A Strategy for producing pure single-layer graphene sheets based on a confined self-assembly approach, Angew. Chem. Int. Ed., 2009, 48: 5864-5868) designed and synthesized a novel amphiphilic molecule having a polymerisable pyrrole group and used it as a structure inducer and a carbon source to prepare a mesoporous silica with a layered structure, and to prepare a single-layered graphene by in situ polymerization of the preorganized pyrrole groups in the mesopores and carbonization using the 2D reaction microcavity formed by the silica, but this method has a high requirement for the amphiphilic molecule which needs specialized design and synthesis, and the 2D template formed by the amphiphicle molecule was poorly stable and may fail in controlled synthesis.

Method for preparing graphene by using two-dimensional confined space between the layers of inorganic layered materials

Beijing University of Chemical Technology


Apparatus and processes are presented to contact a dry, preferably high purity inert gas with a chemical composition in a pressure vessel, or a wetting composition, to form a wet inert gas, which is then used to pressurize the chemical composition out of the pressure vessel. No additional space is needed for an external humidifier. Since a very small amount of vapor is needed to form a wet inert gas, the composition of chemical composition will not be significantly affected.

1. Field of the Invention
This invention is related to chemical composition delivery systems and methods, especially to the chemical delivery systems for electronics specialty chemical compositions, including CMP slurries for wafer polishing.
2. Related Art
Process chemicals for semiconductor manufacturing are usually delivered from bulk containers to user stations with so called chemical delivery systems. High-pressure inert gases, such as nitrogen gas, have become popular for driving chemical compositions from chemical containers to user stations. Compared to the delivery systems having a pump, systems employing high-pressure inert gas for chemical delivery have the advantages of delivery from further distance, and also smooth and pulse-less delivery, thus avoiding impurity shedding from the components of the delivery system.
Although the advantages of such a chemical delivery method have been realized and the method has been practiced in large extent, some concerns and problems have arisen when some of the semiconductor process chemical compositions are delivered with this type of delivery system. For example, inert gas, such as nitrogen gas, will readily dissolve into some of these process chemicals during compression process and eventually form dry spots on wafers. These dry spots become manufacturing defects and seriously reduce the production yield of semiconductor manufacturing. To avoid and eliminate the problem of gas dissolving in chemical compositions, a new delivery system with a bladder installed inside the pressure vessel has been invented. With this method and apparatus, high-pressure nitrogen gas is filled into the bladder to pressurize chemical compositions outside of the bladder. Since there is no direct contact between the chemical composition and nitrogen gas, dissolving of nitrogen gas into chemicals is avoided. Furthermore, chemical compositions will not change in assay due to chemical evaporation.
When delivering aqueous chemical compositions using direct contact with an inert gas, such as slurry compositions used for polishing wafer surfaces, water and other chemical compounds in the chemical composition at the composition surface and composition residuals on the container surfaces will be rapidly lost into the inert gas when the high-pressure inert gas directly contacts with the chemical composition. This is because inert gases are usually very dry and very pure. Amounts of chemical compounds such as water in the chemical composition will change because of evaporation. This change in chemical composition may make the chemical composition function improperly when it is used in the semiconductor manufacturing process. When water evaporates into inert gas, a dry film or dry residuals could be formed with much less water and more concentrated compositions of less volatility. In the case of slurry compositions, this dry film or dry residuals will be in the form of agglomerated particles of larger sizes. These agglomerated particles eventually will be delivered with chemical compositions to user stations and produce scratches on wafer surfaces. This problem could be solved by using the above mentioned bladder technology by preventing the direct contact of nitrogen gas with chemical composition. With this technology, a thin and flexible material that is compatible with the chemical composition must be carefully selected for the bladder.
To overcome the shortcomings of water evaporation into inert gas, a moisturizer can be used to moisturize the nitrogen gas prior to its going into the pressure vessels to pressurize chemical compositions, such as depicted in U.S. Pat. No. 6,076,541. When the moisturized nitrogen gas contacts with chemical compositions, mass transfer of water in the nitrogen gas and the chemical composition is significantly reduced or completely eliminated. Therefore, there is no, or very little, dry residuals or dry film formed within the pressure vessels. However, there are still some drawbacks. First, more space will be needed for accommodating a humidifier near to the pressure vessel. This could be a serious problem because in a semiconductor manufacturing facility, space is always limited. Additional equipment to occupy space is not always permitted and space is not always affordable. Second, moisturized nitrogen gas may create some problems in the system operation. Since moisturized nitrogen flows through a relative long line into the pressure vessel, moisture in nitrogen gas can be condensed in the line because of changes of physical condition. This condensate could block up valves and make the valves malfunction. The condensate could also be carried further into the pressure vessel to dilute the chemical compositions. Chemical composition change by such kind of dilution is forbidden because the composition of chemical compositions must be precisely controlled to meet user""s specification. Further, some chemical compositions, such as hydrogen peroxide in the chemical composition, will evaporate into high purity inert gas even though it is moisturized. Hence, chemical compositions will change when the chemical composition is delivered with such a method although such a change in chemical composition may not be a serious problem for some cases.
It would therefore be advantageous, and an advance in the chemical delivery art, if chemical delivery systems and methods could be designed that reduce or avoid the above-noted drawbacks.
In accordance with the present invention, novel and simple apparatus and methods are proposed to reduce or eliminate the problems of dry residuals and dry film during liquid chemical composition delivery with pressure vessels, as well as problems associated with previously known humidification systems. As used herein the terms xe2x80x9csystemxe2x80x9d and xe2x80x9capparatusxe2x80x9d are used interchangeably.
As used herein the term xe2x80x9cliquid chemical compositionxe2x80x9d means:
a fluid that flows under the presence of pressure, gravity, or combination;
may be Newtonian or non-Newtonian fluid;
may be aqueous, non-aqueous or combination;
may be a combination of components (liquid, solid, and gaseous).
Preferably, liquid chemical compositions which may benefit from the present invention are substantially aqueous, Newtonian fluids having a combination of ingredients, including, in some embodiments, one or more organic compounds, such as reactive diluents, non-reactive diluents, solvents, co-solvents, coupling agents, and the like, and abrasive matter, for example dispersed in individual particles, or agglomerates of individual particles. Chemical-mechanical planarization slurries and chemical-mechanical polishing slurries are two preferred liquid chemical compositions. Suitable organic solvents might include organic alcohols, ketones, acids and the like, isopropyl alcohol, for example.
A first aspect of the invention is an apparatus for delivery of liquid chemical compositions. A first apparatus embodiment comprises:
a) a pressure vessel comprising an inlet and an outlet for a liquid chemical composition, and a vapor space, the pressure vessel adapted to contain the liquid chemical composition, the liquid chemical composition having a vaporizable portion (preferably a major portion of water) therein;
b) means for contacting (preferably bubbling) a dry, preferably high purity inert gas with at least a portion of the liquid chemical composition in the pressure vessel to transfer at least a portion of the vaporizable portion from the chemical composition to the inert gas to form a wet inert gas in the vapor space; and
c) means for pressurizing the chemical composition out of the vessel using the wet, high purity inert gas.
Preferred apparatus within this embodiment are those wherein the inlet and the outlet are each legs of a tee connection, a remaining leg of the tee connected to the pressure vessel. Also preferred are apparatus wherein the dry, preferably high purity inert gas is adapted to be sparged into the pressure vessel near a bottom of the vessel through an inert gas inlet conduit, the inert gas inlet conduit having an exit end, preferably the exit end of the inert gas inlet having a sparging device attached thereto.
As used herein the term xe2x80x9cdryxe2x80x9d means the inert gas preferably has a moisture content less than 10 percent relative humidity (RH), more preferably less than 1 percent RH. xe2x80x9cHigh purityxe2x80x9d as used herein when referenced to the inert gas means the inert gas has less than 10 parts per million (ppm) total impurity (inorganic compounds and organic compounds), more preferably less than 5 ppm. xe2x80x9cUltra high purityxe2x80x9d as used herein when referenced to the inert gas means the inert gas has less than 1 part per billion total impurity (inorganic compounds and organic compounds). One preferred dry inert gas is that referenced in Semiconductor Equipment and Materials International (SEMI) standard C3.29-96, Standard for Nitrogen, Bulk Gaseous, 99.9995% Quality (1999), incorporated herein by reference. The term xe2x80x9cwetxe2x80x9d means a gas composition having components selected from the group consisting of water vapor, organic vapor, inorganic vapor, and combinations thereof.
A second apparatus embodiment of the invention for delivery of liquid chemical compositions comprises:
a) a pressure vessel comprising a first compartment and a second compartment, the first compartment and the second compartment divided by a dividing element;
b) the first compartment connected to an inlet conduit for a wetting composition, and a waste conduit for allowing the wetting composition to be delivered to waste, the dividing element functioning to establish a liquid level of the wetting composition in the first compartment, the first compartment also having a dry, preferably high purity inert gas inlet conduit having an end positioned (preferably adapted to be submerged into the liquid chemical composition to be delivered to waste) to provide contact in the first compartment between the inert gas and the wetting composition to form a wet inert gas, the first compartment further having an outlet for the wet inert gas;
c) the outlet for the wet inert gas connected to the second compartment by a wet inert gas conduit;
d) the second compartment connected to an inlet conduit and an outlet conduit for a liquid chemical composition, and a vapor space, the vapor space connected to the first compartment via the wet inert gas conduit.
Preferred apparatus of the second embodiment are those wherein the conduit is part of a means for monitoring level of the liquid chemical composition inside the second compartment. Also preferred are those apparatus wherein the wet inert gas conduit includes a means for removing liquid droplets from the wet inert gas, such means selected from screens, meshes, mist eliminators, coalescers, adsorbent materials, absorbent materials, molecular sieves, zeolites, filters, heat exchangers, condensers, cryocoolers and the like.
A third apparatus embodiment for delivery of liquid chemical compositions comprises:
a) a pressure vessel comprising a first compartment and a second compartment, the first compartment and the second compartment divided by a dividing element;
b) the first compartment connected to an inlet conduit for spraying a wetting composition into the first compartment, and a waste conduit for allowing the wetting composition to be delivered to waste, the inlet conduit terminating in a means for spraying the wetting composition into the first compartment, the dividing element functioning to establish a level of the wetting composition in the first compartment, the first compartment also connected to a gas inlet conduit for a dry, preferably high purity inert gas, the gas inlet conduit having a terminal end positioned (preferably above a level of the sprayed portion of liquid chemical composition to be delivered to waste) to allow contact in the first compartment between the inert gas and the wetting composition to form a wet inert gas, the first compartment further having an outlet for the wet inert gas;
c) the outlet for the wet inert gas connected to the second compartment by a wet inert gas conduit;
d) the second compartment having an inlet conduit and an outlet conduit for a liquid chemical composition, and a vapor space, the vapor space connected to the first compartment via the wet inert gas conduit.
A fourth apparatus embodiment of the invention for delivery of liquid chemical compositions comprises:
a) a pressure vessel comprising a first compartment and a second compartment, the first compartment and the second compartment divided by a dividing element;
b) the first compartment connected an inlet conduit for spraying a wetting composition into a chamber formed by a housing, and a waste conduit for allowing the wetting composition to be delivered to waste, the inlet conduit terminating in a means for spraying the wetting composition into the chamber, (the dividing element preferably functioning to establish a level of the wetting composition in the chamber), the housing also connected to a gas inlet conduit for a dry, preferably high purity inert gas, the gas inlet conduit and housing adapted to allow contact between the inert gas and the wetting composition in the chamber, the housing further having means for allowing wet inert gas to move into the first compartment;
c) the dividing element having means for allowing passage of said wet inert gas from the first compartment to the second compartment;
d) the second compartment connected to an inlet conduit and an outlet conduit for a liquid chemical composition, and a vapor space, the vapor space fluidly connected to the first compartment via the means for allowing passage in the dividing element.
A fifth apparatus embodiment is a slight modification of the fourth embodiment, and includes the feature that the housing has one or more means for allowing the wetting composition, after contacting the dry inert gas, to traverse through the housing and fall into the second compartment. Preferably, the means for allowing the wetting composition to traverse through the housing are located at location selected from the group consisting of the bottom of the housing, the sidewall of the housing, or both.
It will be understood as included within the scope of the invention that there may exist a plurality of housings inside the first compartment, each having a gas inlet conduit and a conduit for spraying wetting composition into each housing.
A second aspect of the invention includes methods of delivering a liquid chemical composition. A first preferred method embodiment comprises:
a) filling a pressure vessel with a liquid chemical composition comprising a vaporizable component (preferably including moisture), the pressure vessel having a vapor space and adapted to contain the liquid chemical composition;
b) contacting (preferably by bubbling) a dry, preferably high purity inert gas with at least a portion of the liquid chemical composition in the pressure vessel to transfer at least a portion of the vaporizable composition from the liquid chemical composition to the dry inert gas to form a wet inert gas in the vapor space; and
c) pressurizing the liquid chemical composition out of the pressure vessel using the wet inert gas in the vapor space.
A second method embodiment of delivering a liquid chemical composition comprises the steps of:
a) providing a pressure vessel comprising a first compartment and a second compartment, the first compartment and the second compartment divided by a dividing element;
b) at least partially filling the first compartment with a wetting composition, the dividing element functioning to establish a level of the wetting composition in the first compartment;
c) flowing a dry, preferably high purity inert gas into the first compartment in a manner to provide contact between the inert gas and the wetting composition, thus forming a wet inert gas, the first compartment further connected to an outlet conduit for the wet inert gas;
d) flowing the wet inert gas into the second compartment through a conduit; and
e) substantially filling the second compartment with a liquid chemical composition allowing a vapor space, the second compartment connected to the first compartment via the conduit.
A third method embodiment of delivering a liquid chemical composition comprises the steps of:
a) providing a pressure vessel comprising a first compartment and a second compartment, the first compartment and the second compartment divided by a dividing element;
b) spraying into the first compartment a wetting composition, the dividing element functioning to establish a level of the wetting composition in the first compartment;
c) flowing a dry, preferably high purity inert gas into the first compartment (preferably above a level of the wetting composition), and contacting the inert gas with the wetting composition, thus forming a wet inert gas;
d) flowing the wet inert gas from the first compartment into the second compartment through a conduit; and
e) substantially filling the second compartment with a liquid chemical composition, allowing a vapor space, the second compartment connected to the first compartment via the conduit.
A fourth method embodiment of delivering a chemical composition comprises the steps of:
a) providing a pressure vessel comprising a first compartment and a second compartment, the first compartment and the second compartment divided by a dividing element, the first compartment having a chamber formed by a housing;
b) spraying into the chamber a wetting composition, the dividing element functioning to establish a level of the wetting composition in the chamber;
c) flowing a dry, preferably high purity inert gas into the chamber to provide contact between the inert gas and the wetting composition, thus forming a wet inert gas;
d) flowing the wet inert gas into the second compartment through a conduit; and
e) substantially filling the second compartment with a liquid chemical composition, allowing a vapor space, the vapor space connected to the first compartment via the conduit.
The first apparatus embodiment of the invention allows contacting a dry, preferably high purity inert gas with a wetting composition, the wetting composition being the liquid chemical composition to be delivered. Contacting occurs in a pressure vessel to form a wet inert gas, which is then used to pressurize the liquid chemical composition out of the pressure vessel. Therefore, no additional space is needed for an external humidifier as in previous apparatus and methods. Since preferably a very small amount of vapor is needed to saturate the dry inert gas, the assay of the liquid chemical composition will not be substantially affected when the wetting composition is the liquid chemical composition being delivered. The vapor content of the wet inert gas can also be easily controlled by carefully flowing the dry inert gas through the liquid chemical composition, in the first embodiment.
Other preferred embodiments of the presented invention feature two compartments within a pressure vessel of integral body. Liquid chemical composition to be delivered is supplied into one compartment, and a relatively small amount of a wetting composition (which may be the liquid chemical composition being delivered, if desired) and inert gas is supplied into another compartment in such a manner as to cause contact between the dry inert gas and the wetting composition. The two compartments communicate with each other through means described herein. Hence, the liquid chemical composition is propelled with wet inert gas that comprises chemical vapors, preferably water vapor, but not limited thereto. The problem of liquid chemical being lost into the dry inert gas is prevented while the dry residual problem is eliminated at the same time.
With one preferred embodiment, the two compartments as mentioned above communicate with each other through a conduit, allowing wet inert gas to flow into and out of the compartments.
With an additional preferred embodiment, the two compartments as mentioned above communicate with each other through a series of means, preferably small openings such as holes, louvers, channels, and the like in the dividing means separating the two compartments.
All of the embodiments in this invention are provided with necessary control and isolation valves for discharging and recharging liquid chemical compositions into the pressure vessels, introducing in and draining out of liquid chemical composition, and filling and releasing inert gas. The preferred embodiments of the pressure vessels can be operated for delivering chemical compositions with one, or more than one, pressure vessels in parallel. Two or more pressure vessels are usually installed in parallel to continuously deliver liquid chemical compositions. Preferred embodiments of pressure vessels of this invention can also be arranged in series to recharge liquid chemical compositions from one pressure vessel to another.
These and other advantages and aspects of the invention are demonstrated with reference to the following drawings and description of preferred embodiments, although not limited thereto.

Pressure vessel systems and methods for dispensing liquid chemical compositions