A wellbore chemical treating system includes a pressure vessel for containing a treating chemical. The pressure vessel is closed to atmospheric pressure. A first controllably operated valve is disposed in fluid communication between an outlet of the pressure vessel and a well for selectively controlling the flow of the chemical from the pressure vessel to the well. A pressurized gas is disposed in the pressure vessel wherein the pressure exerted by the pressurized gas causes the chemical to flow from the pressure vessel to the well through the first valve when the first valve is opened. A second controllably operated valve is disposed in fluid communication between the well and an outlet of a fluid tank for selectively controlling flow of fluid in the tank to the well. The fluid tank is replenished by fluid produced from the well. The system includes a controller for selectively operating the first valve and the second valve.

1. Field of the Invention
The invention relates generally to the field of chemical treatment systems for use with hydrocarbon producing wells. More specifically, the invention relates to chemical treatment systems which inject "pre flushed" or diluted treatment chemicals into the well.
2. Background Art
In wellbores drilled through the Earth and then used for production of hydrocarbons, a pipe or casing is disposed in the wellbore from the Earth's surface to the bottom of the well. The casing serves to hydraulically isolate the various Earth formations penetrated by the wellbore and to provide the wellbore with a degree of mechanical stability. Typically a tubing string, which is a pipe of considerably lesser diameter than the casing, is positioned within the well casing. The purpose of the tubing string is to enable produced fluids to move to the Earth's surface at greater velocity than would be possible within the casing. The hydrocarbons, and in many cases a considerable amount of connate water, enter the tubing through perforations located at the lower end of the casing, travel through the tubing, to a wellhead at the Earth's surface. In some wells, where the natural fluid pressure in the Earth's subsurface is not sufficient to lift the produced fluids to the Earth's surface, the fluids are pumped to the surface with a "sucker rod" pump or with a downhole electrical submersible pump.
At the Earth's surface, various production equipment directs the produced fluids to holding tanks and/or to a pipeline. The production equipment typically comprises tubing, valves, piping, and other components. The produced fluids typically contain numerous compounds which adversely affect the production equipment. For example, paraffins and water/oil emulsions can coat well production equipment and can eventually plug off the tubing and/or plug the perforations in the casing. In addition, chemical reactions between the produced fluids and metallic equipment can cause scale to be formed on the well production equipment, and some compounds in the produced fluids can corrode the well production equipment.
Various techniques are known in the art to treat these well conditions to extend the useful life of the well production equipment, tubing and casing. In wells susceptible to paraffin build-up, for example, "treater trucks" or "hot oil trucks" are regularly dispatched to pump heated oil and/or heated water into the well. The heated oil and/or water is pumped into the well through the annular space between the tubing and the casing, travels down through the annulus to melt the paraffin deposits in the well production equipment, and the returns to the surface through the tubing. In wells susceptible to corrosion and scale problems, high pressure injection treater trucks pump batches of chemicals into the well to chemically remove the scale, and to inhibit the causes of corrosion. All of these techniques require regular maintenance services which are costly and which do not continuously treat the well. Treater truck or batch treatment of wells is less efficient than continuous treatments because more chemicals are typically injected in batch treatment operations.
To avoid inefficiencies associated with treater truck maintenance of hydrocarbon producing wells, it is known in the art to use mechanical pumps to inject chemicals into a well. Typically, mechanical pumps are supplied from a storage tank which holds the chemicals. The mechanical pumps and storage tanks are located adjacent the well for several reasons, such as for reducing the length of power cable or piping that connects the pump to a power source such as electricity or natural gas. The tanks are located above the pump and the chemical is gravity fed to the intake port of the pump. The tanks include a vent at the upper end of the tank to prevent a vacuum from developing in the tank as the pump draws chemical from the tank. In addition, the vent releases excess pressure within the tank caused by thermal expansion of the chemical. Such thermal expansion can cause the chemical vapors to be released into the environment through the vent. In addition, thermal expansion can cause the chemical to be ejected through the vent or through the sight glass used to indicate the chemical level in the tank. In either event, chemical vapors or the chemical fluids are released in an uncontrolled manner and can pose a hazard to personnel and to the environment.
The mechanical pumps used in typical chemical injection systems are powered by electricity or gas and include numerous moving components. It is customary to inspect these pumps on a regular basis, sometimes daily, to verify the operability of the pumps. Because the chemical is gravity fed to the intake of the chemical pump, sediment in the tank or the chemical settles toward the pump intake and can interfere with the operation of the pump In addition, the presence of an air bubble in the intake line may impede the operation of the pump because of a vapor lock. In such event, maintenance personnel routinely open a bleeder valve on the pump and release chemical from the pump until the air bubble has been cleared. This practice is undesirable because it releases chemical into the environment. An additional consideration with respect to venting a chemical pump system to the atmosphere is introduction of moisture into the chemical system, which may condense and foul the chemical.
One device known in the art for providing controllable, continuous chemical treatment for well production equipment is disclosed in U.S. Pat. No. 5,209,300 issued to Ayres. An apparatus and method described in the Ayres '300 patent include a vessel which holds the chemical and a pressurized gas which exerts a pressure on the chemical. A pressure regulator and a valve selectively control the injection of the chemical into the well as the pressurized gas urges the chemical out of the vessel. The pressurized gas drives the chemical through the regulator, valve, and into the well without venting the chemical or pressurized gas into the ambient environment. The apparatus described in the Ayres '300 patent is adapted to inject chemicals into the well in essentially undiluted form. As will be explained below, in certain cases it is desirable to pump undiluted chemicals into a wellbore and follow such injection with a water flush.
So called "batch treatment" is among the more widely used methods used for downhole treatment of sucker rod pumped wells. A treater truck is dispatched to the well. The chemical is placed into the annulus in undiluted form, and is followed by an "overflush" of water to assure proper treatment of the well, because sucker rod pumped wells are susceptible to "pump off", whereby the pump is operated at such a rate as to essentially remove all the fluid from the well down to the level of the pump In such cases, there is substantially no fluid to dilute and disperse the treating chemical, making the treatment less effective. The overflush is intended to provide sufficient dispersing fluid for the treatment chemical so that the chemical can reach the bottom of the well. The chemical would otherwise need to travel the entire distance from the surface in undiluted form, often against upward flow of gas in the well. Typically, the chemical can dry out inside the well before ever reaching the bottom when injected in undiluted form. The overflush water, however, is typically taken from storage tanks located near the well for storing, and subsequent environmentally safe disposal, of connate water that is produced from the well along with oil and gas. The water in the tanks is often contaminated with high levels of oxygen and sulfate reducing bacteria. When reinjected into a well, such cross-inoculation of contaminates lessens the effectiveness of typical corrosion inhibitor chemicals, among other problems. The truck batch treatment process in effect provides a recirculation of the corrosive materials through the entire well, and any other wells sharing the same surface production equipment, on a periodic basis. Some method is needed to break this cycle so that the fluid used to protect the system is not part of the problem.

This patent is subject to a terminal disclaimer.

Automatic chemical treatment system with integral flush fluid dispenser and method for using the same


Information for configuring control apparatus for a power system including a plurality of controlled power supplies is produced using a graphical interface which displays the topology and sequencing of the power supplies in the power system. A database is used to select power supplies to add in determining the power system topology. Sequencing is represented by displacing icons representing the power supplies along lines representing their input and output voltages, and arrows representing startup sequence dependencies. A processor produces the configuration information, consistent with the displayed topology and sequencing, using information for the selected power supplies from the database, for downloading to the control apparatus.

The related applications describe and claim aspects of a power supply controller which can be used for controlling a plurality of isolating and/or non-isolating power supplies, such as switch mode power supplies or DC power converters, and linear voltage regulators, for providing controlled electrical power to loads. For example, the power supplies may provide different supply voltages to various electrical circuits on a circuit card on which the power supply controller is also provided. As described in the related applications, the power supply controller has six converter state machines (CSMs), one for each of up to six controlled power supplies, and an input state machine (ISM) for an input or supply voltage for the controlled power supplies.
A primary aspect of the control of the power supplies relates to their sequencing in accordance with conditions monitored by the power supply controller. Sequencing refers to an order in which, and parameters in dependence upon which, the power supplies are enabled or started up in a power-up process, disabled or shut down in a normal power-down process, and/or disabled or shut-down in a fault situation. The monitored conditions include, for example, the input voltage and the output voltages produced by the respective power supplies. For example, enabling of each individual controlled power supply on power-up of the circuit card can be dependent upon the input voltage, or upon a monitored output voltage of a prior-enabled power supply, exceeding a threshold voltage.
The related applications by D. Brown et al. disclose arrangements of controlled power supplies that can provide relatively arbitrary sequence topologies, and that allow for a location of each controlled power supply on either a main circuit board or a daughter board. As described in these applications, various configuration registers are provided in the power supply controller to identify the presence and locations of the controlled power supplies and their sequencing for power-up, normal shut-down, and shut-down in a fault situation.
In addition to this information, it is desirable to be able to vary, and it is therefore necessary to specify for desired operation of the power supply controller, a large amount of other configuration information relating to the controlled power supplies and their sequencing.
By way of example, such other information can include, for each controlled power supply, under- and over-voltage thresholds and associated time periods for triggering warnings and detecting fault conditions in operation of the controlled power supply, a mask time period for start-up to be completed before under-voltage monitoring takes effect, a start-up voltage threshold which must be exceeded to trigger a subsequent CSM in the power-up sequence of the controlled power supplies, a restart voltage threshold below which the monitored voltage must fall before a power-up sequence is initiated following a shut-down of the controlled power supplies, voltage parameters for adjustment or trimming of the controlled power supply output voltages, and time delay periods associated with the power-up, normal shut-down, and fault shut-down sequences.
Such other information can further include a threshold voltage and related period which must be exceeded by the input voltage for a power-up sequence of the controlled power supplies to begin, and information related to the use of general purpose input/output (GPIO) pins of the power supply controller.
All of this and any other desired information for operation of the power supply controller, collectively referred to herein as configuration information, must be correctly set up for operation of the power supply controller. For example, the configuration information is stored in a non-volatile random access memory (NVRAM) of the power supply controller, and is downloaded from the NVRAM to registers of the power supply controller on power-up of the power supply controller.
While such a power supply controller is very versatile, it can be seen that its configuration information is relatively complex. Voltage thresholds and time delays such as those identified above, especially those relating to power supply sequencing for power-up and shut-down, must be correctly set for operation of the power system; if even one of the registers for this configuration information is set incorrectly the power system may be rendered inoperable. Furthermore, the configuration of the power supply controller may be by power system designers who have previously used only analog power system control circuits and who are not familiar with a configurable power supply controller such as described above.
Accordingly, there is a need to facilitate such configuration of a power supply controller.

Graphical interface for configuring a power supply controller


The present invention provides a screening tool and screening method for obtaining a substance useful as a prophylactic and/or therapeutic drug for diseases associated with 5-HT production/secretion abnormalities, including digestive organ diseases, and a prophylactic and/or therapeutic drug for diseases associated with 5-HT production/secretion abnormalities, including digestive organ diseases. Examples of digestive organ diseases in the present invention include constipation type irritable bowel syndrome, functional dyspepsia, constipation, diarrhea type irritable bowel syndrome, diarrhea and vomiting.

Serotonin (hereinafter referred to as 5-HT) is abundantly contained in fruits such as bananas, vegetables, harmful plants and the like. In animals, 90% of 5-HT in the living body is present in the gastrointestinal tract. The 5-HT in the gastrointestinal tract is biosynthesized in gastrointestinal mucosal chromaffin cells (enterochromaffin cells; hereinafter referred to as EC cells), entering the blood circulation, and is transported to the whole body. The 5-HT released upon chemical stimulation or mechanical stimulation of the gut binds to 5-HT receptors of target cells to cause physiological reactions. As 5-HT receptors involved in digestive tract movement functions, 5-HT receptor 1, 5-HT receptor 2, 5-HT receptor 3, 5-HT receptor 4, 5-HT receptor 7 and the like have been recognized. These receptors have been shown to be expressed in the nerve cells and smooth muscles of the gastrointestinal tract. The 5-HT released from EC cells controls digestive tract movement functions via the nerve cells and smooth muscles that express these 5-HT receptors. Hence, 5-HT is thought to be a kind of hormone that regulates gastrointestinal tract functions (non-patent document 1).
Although it has been known that when chemical stimulation or mechanical stimulation is given to EC cells, 5-HT release is promoted and gut movement is accentuated, little has been demonstrated about what is the molecular mechanism by which the above-described promotion of 5-HT release from EC cells is caused.
Currently, in the clinical settings for the field of digestive organ diseases, drugs that control the activity of 5-HT receptors are used. For example, 5-HT receptor 3 inhibitors are used to treat diarrhea type IBS, as antiemetics, and for other purposes, whereas 5-HT receptor 4 activators are used to treat constipation type IBS and digestive organ dysfunction and for other purposes. Because many IBS patients have an abnormality in postprandial blood 5-HT level, it has been demonstrated that 5-HT is associated with the pathologic condition. However, not many therapeutic drugs offer high satisfaction for patients with constipation type IBS or other digestive organ diseases (non-patent document 1).
TRPA1, belonging to the TRP (Transient Receptor Potential) channel family, was recently reported to be a temperature-sensitive channel, and TRPA1 was reported to become activated at temperatures of 17° C. or lower, and to become activated by nociceptive cold stimulation (non-patent document 2). It was also demonstrated that TRPA1 serves as a ligand agonizing ion channel that becomes activated not only by low temperatures, but also by stimulants such as mustard (non-patent document 3, patent document 1).
Furthermore, from experiments using TRPA1-deficient mice, it was demonstrated that TRPA1 activates primary afferent nociceptors to cause inflammatory algesia (non-patent document 4). From these experimental results, it is thought that TRPA1 plays an important part in the transmission mechanism by which an exogenous stimulant and an endogenous pain inducer cause inflammatory pain.
Although functions of TRPA1 concerning the sensory nerves and the like are already commonly known as described above, there is no research report on the roles of TRPA1 in the digestive tract, and its functions in the gut remain elusive.
[Patent document 1] WO2005/089206
[Non-patent document 1] TEXTBOOK of Gastroenterolorogy, Fourth Edition, ISBN 0-7817-2861-4
[Non-patent document 2] Cell, Vol. 112, 819-829(2003)
[Non-patent document 3] Nature, Vol. 427, 260-265(2004)
[Non-patent document 4] Cell, Vol. 124, 1269-1282(2006)


A communications device configured to extract weighting factors from incoming signals received from two or more antennas while estimating a channel ratio for the signals. The device includes at least one antenna and a digital signal processor. The method includes receiving two signals and extracting the weighting factors while estimating the channel ratio.

1. Technical Field of the Invention
The present invention relates generally to wireless systems and more particularly to determining ratio estimations and weightings for multi-antenna verification.
2. Background Information
The increasing use of wireless communications leads to a need for clearer transmissions using less to do more. The move to multiple antenna systems has caused a need for new ways to balance transmissions over more than one antenna to one or more receiving antennas. In some cases, weighting factors may be used for balancing the transmissions. It is thus desirable to implement a convenient way to determine weighting factors from a received transmission to maximize some transmission condition, such as a maximized signal to noise ratio.

Joint ratio estimation and weights detection in closed loop transmit diversity


An optimal maximum likelihood signal detection method and apparatus for a MIMO system are disclosed. An embodiment of the invention can provide an optimal signal detection method for a multiple-input multiple-output system that includes: determining the smallest metric of the final layer expanded from the candidate symbols of the i-th detection layer as the optimal threshold of the i-th detection layer; and selecting surviving candidate symbols from among the candidate symbols of the i-th detection layer by using the optimal threshold.

1. Technical Field
The present invention relates to an optimal maximum likelihood signal detection method and apparatus for a MIMO system that can provide optimal signal detection of the same quality as maximum likelihood detection by setting an optimal threshold for selecting the number of surviving candidate symbols variably for the adaptive detection of signals in each detection layer according to the channel environment or the signal-to-noise ratio (SNR) based on the QR decomposition (QRD)-M algorithm in a MIMO system.
2. Description of the Related Art
A multiple-input multiple-output (MIMO) system can increase system efficiency without additional bandwidth or increased transmission power. For this reason, the MIMO system is widely being employed or considered in current communication standards.
Maximum likelihood (ML) detection is known as an optimal algorithm for signal detection in a MIMO system. Although ML detection provides an optimal error performance, there is the drawback that its computational complexity grows exponentially according to increases in the number of multiple inputs at the transmitter and in modulation order. Due to such increase in computational complexity, it may actually be impossible to implement in communication and/or broadcasting systems having a large number of multiple inputs (the number of antennas or the number of channels) or a high modulation order. For example, the Long Term Evolution (LTE)-advanced standard employs the Single Carrier Frequency Division Multiple Access (SC-FDMA) technology for the uplink, and if 4-Quadrature Amplitude Modulation (QAM) and 16-QAM modulation were applied and two resource blocks (RB: 1 RB being 12 subchannels) were allotted to a user, then a ML detection for a receiver would require computing the Euclidean norm 424=248 times (approximately 281 trillion times) and 1624=296 times (approximately 7.9×1028 times), respectively, which cannot be achieved with a typical personal computer.
In recent times, near ML detection methods have been proposed, such as the QRD-M detection method, which when applied in a signal detection algorithm provides a bit error rate (BER) performance comparable to that of the ML detection method. This can reduce complexity compared to ML detection while providing a performance comparable to the BER of ML detection, but cannot provide the same BER performance as does ML detection, and hence is referred to as "near ML" detection.
For instance, the QRD-M detection algorithm performs signal detection by selecting M candidate symbols in each detection layer and can reduce complexity compared to ML detection. However, the conventional QRD-M detection algorithm may constantly select candidate symbols for each detection layer. As a result, in the conventional QRD-M detection algorithm, the number of candidate symbols M should be set to a large value in order to obtain a comparable BER performance to the ML detection, and since a fixed M number of candidate symbols are selected for each detection layer even when the received SNR is high, the efficiency of the computational complexity may be degraded.
An adaptive threshold method was proposed as an improvement in which M candidate symbols are selected variably in each detection layer, but because an optimal threshold cannot be applied for each detection layer, it cannot achieve the same BER performance as that of ML detection and remains at a performance level comparable to the near ML detection methods.

Optimal maximum likelihood signal detection method and apparatus for MIMO system

INDUSTRY-UNIVERSITY COOPERATION FOUNDATION HANYANG UNIVERSITY


The subject authentication scheme encompasses a large family of authentication systems which may be built over existing transmission systems. By superimposing a carefully designed secret modulation on the waveforms, authentication is added to the signal without requiring additional bandwidth. The authentication information (tag signal) is sent concurrently with data (message signal). The authentication is designed to be stealthy to the uninformed user, robust to interference, and secure for identity verification. The tradeoffs between these three goals are identified and analyzed. The use of the authentication for channel estimation is also considered, and improved bit errors are demonstrated for time-varying channels. With a long enough authentication code word an authentication system is achieved with very slight data degradation. Additionally, by treating the authentication tag as a sequence of pilot symbols, the data recovery may be improved by the aware receiver.

In conventional digital communications systems, a sender uses a message signal to transmit message symbols to a receiver. The sender and receiver agree upon a transmission scheme such that the mapping between signals and symbols are unique and known by both parties. In order to satisfy requirements for stealth, robustness, and security of a communication system, authentication, integrity, and secrecy of the signal transmission via a transmitting media is to be provided. For an authentication system, uniqueness and non-reproducibility of the identification signal are of the utmost importance.
Research in authentication techniques have focused mostly above the Physical Layer (PHY) of the Open System Interconnection (OSI) model underlying the operation of the network system. As is known to those skilled in the art, the OSI model is an abstract description for layered communications and computer network protocol design. The OSI divides network architecture into seven layers, out of which the Physical Layer (PHY) is the bottom layer. The function of the PHY is to define the electrical and physical specifications of a device, and, in particular, to define the relationship between the device and a physical medium, including performing encoding and signaling functions that transform data from bits residing within a device into signals to be sent over the network. The PHY also defines specifications as to data transmission and reception at the device.
There are two paradigms conventionally used in communication systems for adding authentication: multiplexing or embedding. Examples of multiplexed authentication may be represented by message authentication codes or authentication protocols that require a series of message devoted to authentication. An overview of these methods may be found in G. J. Simmons, "A survey of information authentication", Proceedings of the IEEE, Volume 76, Issue 5, May 1988, pp. 603-620; as well as in Chapters 9 and 10 of A. J. Menezes, P. C. van Oorschot, and S. A. Vanstone, "Handbook of Applied Cryptography", 5th printing, CRC Press, 2001. The advantage of these methods is that the authentication is received with the same quality as the data. However, data throughput is penalized since some of the bits carry authentication instead of data.
In 1972, T. Cover, "Broadcast channels", IEEE Transactions on Information Theory, Volume 18, Issue 1, January 1972, pp. 2-14 analyzed broadcast channels and demonstrated that high joint rates of transmissions are best achieved with simultaneous, as opposed to time-multiplexed, transmissions. Digital watermarking follows the paradigm of embedded signaling by modifying the data in a controlled manner that provides additional information to the receiver. Authentication may be transmitted in this manner as presented in C. Fei, D. Kundur, and R. H. Kwong, "Analysis and Design of Secure Watermark-based Authentication Systems", IEEE Transactions on Information Forensics and Security, Volume 1, No. 1, March 2006, pp. 43-55; as well as in L. M. Marvel, C. G. Boncelet, and C. T. Retter, "Spread Spectrum Image Steganography", IEEE Transactions on Image Processing, Volume 8, Issue 8, August 1999, pp. 1075-1083. The embedded signaling for adding the authentication has proven to provide stealthy authentication. However, as opposed to the multiplexing approach, embedding of additional information degrades the data quality (I. J. Cox, M. L. Miller, and A. L. McKellips, "Watermarking as Communications with Side Information", Proceedings of the IEEE, Volume 87, Issue 7, July 1999, pp. 1127-1141). Much of the research in digital watermarking has focused on watermarking multimedia data and minimizing the distortion at the receiver in terms of human perception.
At the Physical Layer, work has been done in authenticating the sender and receiver based on prior coordination or secret sharing, where the sender is authenticated if the receiver can successfully demodulate and decode the transmission. Spread spectrum techniques, such as direct sequence and frequency hopping, may be viewed as examples of physical layer authentication systems (J. G. Proakis, Digital Communications, 4th ed. New York: McGraw-Hill, 29000, Chapters 5, 13). While these techniques are covert and provide robustness to interference, they achieve this at the cost of bandwidth expansion. Additionally, if it is desired to add authentication to a system in a stealthy way so that users unaware of the authentication continue to communicate without modifications to hardware or protocol, the technique does not serve this purpose well, since only authenticated parties with knowledge of the secret are allowed to participate in communications. The need for such stealth arises, for example, when authentication is piggybacked onto an existing system.
The idea of transparently adding information at the physical layer has been studied for some specific cases. S. H. Supangkat, T. Eric, and A. S. Pamuji, "A public key signature for authentication in telephone", APCCAS 2002, Volume 2, pp. 495-498 proposed one such authentication scheme for telephony where an encrypted hash of the conversation is added back into the signal. Similarly, J. E. Kleider, S. Gifford, S. Chuprum, and B. Fette, "Radio Frequency Watermarking for OFDM Wireless Networks", ICASSP 2004, Volume 5, pp. 397-400 proposed a scheme where a low-power watermark signal is added to the data signal with spread spectrum techniques. X. Wang, Y. Wu, and B. Caron, "Transmitter identification using embedded pseudo random sequences", IEEE Transactions on Broadcasting, Volume 50, Issue 3, September 2004, pp. 244-252 proposed a scheme for broadcast television where each transmitter adds a unique low-power signal to its transmission in order to prove its identity to the receivers.
The transparent transmission of data may also be built by using multi-resolution transmission, where varying levels of protection are guaranteed for multiple data streams as presented in L. F. Wei, "Coded modulation with unequal error protection", IEEE Transactions on Communications, Volume 41, Issue 10, October 1993, pp. 1439-1449; P. K. Vitthaladevuni and M. S. Alouini, "Exact BER computations of generalized hierarchical PSK constellations:", IEEE Transactions on Communications, Volume 51, Issue 12, December 2003, pp. 2030-2037; and M. Morimoto, M. Okada, and S. Komaki, "A hierarchical image transmission system in a fading channel", Fourth IEEE International Conference on Universal Personal Communications, November 1995, pp. 769-772. With this scheme, data symbols are sent at high rate while the authentication is sent at a lower rate. Multi-resolution (also known as asymmetric or nonuniform) constellations provide important data signal points to be far apart while less important signal points are close together.
Authentication at the physical layer may be viewed as a special use of pilot symbols inserted in the transmitted signal, since the authentication signal is verified and therefore known at the receiver. However, a subtle difference arises since the authentication signal may or may not be present in the received signal. Pilot symbols are either time division multiplexed (TDM) or superimposed (SI) with the transmitted messages. M. Dong, L. Tong, B. M. Sadler, "Optimal insertion of pilot symbols for transmission over time-varying flat fading channels" IEEE Transactions on Signal Processing, Volume 52, Issue 5, May 2004, pp. 1403-1418 showed that SI schemes may outperform TDM schemes when the transmission channel becomes sufficiently time varying. For a packet-based multi-carrier system, J. E. Kleider, G. Maalouli, S. Gifford, S. Chuprun, "Preamble and embedded synchronization for RF carrier frequency-hopped OFDM", IEEE Journal on Selected Areas in Communications, Volume 23, Issue 5, May 2005, pp. 920-931 suggested that SI pilot symbols may be used for channel acquisition while incurring only a 1 dB penalty when compared to a TDM training scheme.
Although a vast amount of research has been performed in the field of authenticated communication there still is a need to improve stealth, robustness and security of authentication schemes by hiding the authentication in the physical waveform while maintaining high levels of robustness and security.

Wireless communication method and system for transmission authentication at the physical layer

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


A liquid crystal display has, a plurality of pixel including a switching element, a plurality of gate lines extending transversally, a plurality of data lines extending longitudinally, a first storage electrode line extending transversally, a second storage electrode line extending longitudinally, a third storage electrode line connecting two of the adjacent second storage electrode line, a repair assistant formed in an area that the data line crosses over the third storage electrode line. The liquid crystal display can be repaired with good quality by shortening the repair path.

1. Field of the Invention
The present invention relates to a liquid crystal display (LCD), an array substrate characterizing a large size display, and a method for manufacturing the array substrate and the LCD.
2. Discussion of the Background
A liquid crystal display (LCD) comprises a lower substrate, an upper substrate and a liquid crystal (LC) layer confined between the upper substrate and the lower substrate. A pixel electrode is formed on the lower substrate, which may also be referred to as a thin film transistor substrate. The upper substrate may comprise a common electrode and a color filter layer. The upper substrate is assembled with the lower substrate to confine the LC layer and to form an LCD panel. The LCD displays images by applying electric field to the liquid crystal (LC) layer and by controlling light intensity transmitting through the device. The LCD also comprises a data driving circuit, a gate driving circuit, and a signal controlling circuit.

Thin film transistor array substrate, method for manufacturing the same, liquid crystal display having the substrate, and method for manufacturing the liquid crystal display


A system may be provided that includes a random access memory, a non-volatile solid state memory, a serial non-volatile semiconductor memory, and a memory controller. The non-volatile solid state memory may include a boot block and a code partition. The serial non-volatile semiconductor memory stores a last written boot sector identifier. The memory controller may be configured to read the last written boot sector identifier from the serial non-volatile semiconductor memory and find a last written boot sector of the boot block based on the last written boot sector identifier read from the serial non-volatile semiconductor memory.

When booting a non-volatile solid state memory device, such as a flash drive, a boot loader may load and initialize firmware that implements a block storage protocol, such as SATA or ATA. The firmware may be stored in the non-volatile solid state memory of the device. In order to initialize and/or load the firmware, the boot loader may read parameters from the non-volatile solid state memory of the device.
The parameters may vary over time. As a result, the parameters may be written to the non-volatile solid state memory of the device when the device is being shut down, for example. Accordingly, when the boot loader reads the parameters from the non-volatile solid state memory, the parameters should have the correct values.
To increase the endurance of the non-volatile solid state memory, the parameters may be written to a new location, such as a new sector, in the non-volatile solid state memory each time the parameters are written. When booting the device, the boot loader may search sectors in a block of the non-volatile solid state memory for a sector in which one or more of the parameters are stored.

Expedited find sector to decrease boot time


The present description relates to a method in which a multi-radio access technology (RAT) terminal transceives data to/from a first base station that supports a first RAT and to/from a second base station that supports a second RAT, in a radio access system which supports multi-radio access technologies (RATs). The multi-RAT terminal transmits, to the first base station, a multi-RAT capability negotiation request message containing control information indicating the second base station which is preferred for communication, thereby simplifying a scanning process for the second base station and thus reducing the power consumption of the multi-RAT terminal.

1. Field of the Invention
The present invention relates to a radio access system supporting multi-radio access technology (RAT) and, more particularly, to a method and apparatus for transmitting and receiving data over two or more heterogeneous networks.
2. Related Art
In a conventional radio communication environment supporting two or more heterogeneous networks, although a terminal has capabilities to access multi-RAT, the terminal is unable to access the multi-RAT at the same time and transmit and receive data to and from the two or more heterogeneous networks at the same time.
That is, a conventional terminal supporting multi-RAT accesses any one RAT based on switching and transmits and receives data over one network. Accordingly, if a terminal having multi-RAT capabilities transmits and receives data over a specific network and transmits and receives data over a network different from the specific network, the transmission and reception of data over any one network is stopped.
Accordingly, in the prior art, a terminal having capabilities supporting two or more heterogeneous networks is able to perform communication by using different networks, but efficiency is limited because the terminal operates based on simple switching.
Furthermore, since different networks independently operate, an inefficient operation is performed from a viewpoint of the overall flow management of a terminal.
Accordingly, a method of a mobile station (MS), having a multi-RAT capability, transmitting and receiving data at the same time over 2 or more networks has been defined. However, overall contents of a multi-RAT capability negotiation process procedure have been defined, but detailed solutions to detailed contents and method of each operation have not been proposed.
In particular, it is clear that a multi-RAT MS must perform a scanning procedure on a secondary system in order to transmit and receive data to and from heterogeneous networks, that is, a primary system and the secondary system at the same time, but there is no detailed solution regarding that the a multi-RAT MS has to perform scanning on the secondary system through what method.
Furthermore, the number of APs belonging to the coverage of a cellular network is gradually increased, and that an MS scans all neighbor APs can be inefficient in terms of power efficiency.

Method and apparatus for transceiving data in a radio access system which supports a multi-radio access technology


The automatic troubleshooting of failed single sign on attempts via an identity provider to a service provider. When an error message is encountered due to that failed single sign on attempt, that error message is used to automatically identify a root cause of the failure of the single sign on attempt. In some embodiments, a resolution of the failure is also identified, and a tool for the resolution automatically provided to the user. Such failures in single sign on attempts usually are due to improper configuration information being provided to the identity provider. The principles described herein allow a user to test ahead of time whether they have provided proper configuration information to the identity provider, and potentially correct any problems in the single sign on experience in advance, perhaps well in advance of actually needing a resource provided by the service provider.

Many applications (also called "service providers") are offered over the Internet, often in cloud computing environments. In order to ensure the right services are provided to the right user, it is critical to authenticate the user to verify their identity. Accordingly, service providers often require the user to sign on by providing appropriate credentials. Sometimes, a user would like to sign on to multiple related service providers.
"Single sign on" is a procedure that allows the user to sign onto one of the multiple related service providers, without having to perform a separate sign on for each. An example is when one of the services is an identity provider, and another is a hosting service provider that hosts a resource that the user wants access to. The hosting service provider trusts assertions by the identity provider regarding the identity of users and/or authorizations for those identities.
The user issues a request to access the resource from the hosting service provider. The hosting service provider redirects the user to an identity provider that the hosting service provider trusts. The user then signs on with the identity provider, which provides information (perhaps in the form of a token) that the user then relays back to the hosting service provider. The hosting service provider verifies that the information did indeed originate from the trusted identity provider, and then authenticates the user based on that information. The hosting service provider then decides access control of the resource based on that authentication. In this case, the user really only had a single sign on experience with the identity provider.
When a user sets up a service provider to provide a single sign on experience with a particular identity provider, the user will provide configuration information to the identity provider. This configuration information is used by the identity provider when receiving a sign on request from the user, and to send appropriate information back to the user for relay to the hosting service provider. If there is something wrong with the configuration information, the single sign on experience may fail. That is, the identity provider might respond with an error message. Even if there was no error message, and the identity provider provides the information in the form of a token, the service provider itself may still respond with an error message.
The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some embodiments described herein may be practiced.


A connector assembly that includes an insulation displacement member including a hydrophobic organosilane mono-layer protective coating is disclosed. In one embodiment, the connector assembly may be manufactured by a method that includes assembling the connector assembly, contacting the connector assembly with an organosilane coating solution, and curing the organosilane coating solution. The connector assembly may be assembled by mechanically supporting the insulation displacement member with a connector framework. The connector assembly may be contacted with the organosilane coating solution by contacting at least the wire engaging portion of the insulation displacement member and at least a portion of the connector assembly with the organosilane coating solution.

Field
The subject matter of the present disclosure generally relates to electrical connectors comprising insulation displacement members.
Technical Background
Electrical circuits, and in particular telecommunications networks, make extensive use of electrical connectors, sometimes referred to herein as connector assemblies, to quickly and easily establish electrical connections with insulated electrical conductors, such as insulated wires. For example, electrical connections need to be established between a service provider, such as a telephone company or an internet service provider, and the subscriber. In telecommunications networks, electrical connectors are typically disposed within wire termination devices, such as line modules, protected terminal devices, and station protectors, and establish the necessary electrical connections throughout the network.
Some electrical connectors utilize insulation displacement type connectors, which contain an insulation displacement member that serves to break through the insulation of an electrical conductor. In these types of connectors, the insulation on the electrical conductor may not need to be removed prior to connection between the electrical conductor and the electrical connector. For example, an insulation displacement member may cut through the insulation of the insulated electrical conductor, such as an insulated wire, to establish electrical continuity between the insulation displacement member and the electrical conductor.

Connector assemblies and methods of manufacture


The invention provides a method and system for packet processing, in which a router (or switch) is capable of quickly processing incoming packets, thus performing level 2, 3, and 4 routing and additional services, in real time. A system includes a packet processing engine (PPE), having elements for receiving packets, distinguishing header and payload information for those packets, outsourcing router decision-making to additional hardware resources such as a fast forwarding engine (FFE), and forwarding those packets. The PPE is synchronized to the FFE, so that the PPE can send and the FFE can receive packets at each one of a sequence of constant-duration time quanta. Similarly, the PPE can receive and the FFE can send packet routing information at each one of a sequence of similar time quanta. The PPE and the FFE have separate hardware so that their functions can be performed in parallel without contention for operating resources.

1. Field of the Invention
This invention relates to packet processing.
2. Related Art
In a computer network for transmitting information, messages are received by each router (or switch) at an input interface and retransmitted at an output interface, so as to forward those messages onward to their respective destinations. Each router performs a lookup operation for each message it encounters, in which the router determines from the message to which output interface the message should be forwarded.
One problem in the known art is that the lookup operation can be relatively complex, and can use a relatively large amount of processor resources. For example, the lookup operation can be complicated by concurrently determining one or more of the following:                which output interface is the closest, within a defined network topology, to the specified destination;        whether the message is unicast or multicast, and in the latter case, from which input interface the message was received;        whether the message is authorized to be forwarded by this router from its specified source, and whether the message is authorized to be forwarded by this router to its specified destination;        whether the message should be forwarded to a selected output interface for quality of service considerations, security considerations, or other administrative considerations;        whether the message should be counted, measured, or otherwise accounted for, concurrently with forwarding.
Known responses to this problem include (1) to provide greater processing capability, so as to make up for the processor load on the router, (2) to provide only some of these concurrent services, or to provide them only a reduced functionality. While these responses achieve the goal of routing messages in a forwarding network, they have the disadvantage that added services introduce additional load on the router processor and slow down the router.
Accordingly, it would be advantageous to provide a method and system for packet processing that is not subject to drawbacks of the known art.


Centrifugal turbomachines, such a centrifugal compressors, centrifugal blower, and centrifugal pumps, having unique treatments that enhance their performance ranges. In one arrangement, the treatment involves injecting a relatively high-momentum flow proximate to the blade-tip clearance gap at the inlet to the impeller of the turbomachine in a manner that reenergizes flow at the gap. The injected high-momentum flow can be taken from a location downstream of the outlet of the impeller and/or from a flow external to the turbomachine. In another arrangement, the non-self-bleed-type treatment involves providing the centrifugal turbomachine with a secondary flow path upstream of the inlet to the impeller. In one example, the flow of working fluid to the secondary flow path is modulated according to the mass flow of the working fluid. During times of higher flow, the secondary flow path is opened, and at times of lower flow, the secondary flow path is closed.

The performance characteristics of a given turbocharged internal combustion engine (ICE) rely on the proper selection and integration of turbomachinery elements. Component efficiency levels and flow capacities, coupled with the limits of stable compressor operation, heavily influence the overall power output, transient response, and emissions control strategies available to engine designers. To address tightening emissions requirements, most of the emerging clean combustion strategies rely on heavy exhaust gas recirculation (EGR) and subsequently place higher demands on the turbocharger and proper turbocharger-to-ICE matching.
In general terms regarding compressor performance requirements, the approach for reduced emissions via higher EGR utilization is in direct opposition to achieving a rated engine power condition. Since a portion of the charge air is recycled at high pressure, high EGR has the effect of increasing the required compressor pressure ratio, while reducing the necessary mass flow rate, thus driving the compressor towards or past the stable operating limit. In opposition to the low-flow requirements of the high EGR, low-emissions strategy is the rated power condition, typically requiring substantially higher flow with equivalent or slightly increased pressure ratio.
As the operating range requirements are increased for a single stage centrifugal compressor, an apparent limit in usable range is reached. Useable range is typically defined as a region where the compressor efficiency exceeds a desired minimum threshold value. Typically, the minimum level of efficiency is based on the duty cycle and life requirements of the various interacting system components, including the compression stage. Stable operating range can be increased further without improving the usable operating range, thus yielding minimal benefits. Due to the extremely broad required range, oftentimes the solution is two compressors (small and large) designed to deliver high performance levels at differing flow rates. The changeover between the small and large compressors is regulated via valves. To achieve the desired range in a single compressor requires compromises in the design process. Traditionally, recirculating casing treatments are applied to the baseline compressor to extend the stable operating range. The primary approach is that flow is removed from the mid-passage region (between compressor leading and trailing edge) and then re-introduced upstream of the compressor inlet.
To improve internal combustion engine emissions levels, exhaust gas is recirculated in varying amounts. Typically, exhaust gas is removed upstream of the turbine at high temperature and pressure and re-introduced at high pressure prior to entering the cylinders of the engine. The EGR loop can pass through an EGR cooler and can have a throttle valve in place to modulate the flow rate.

Centrifugal turbomachines having extended performance ranges


The present invention provides a packet detector for use with a packet-based wireless receiver employing a receive antenna for P concurrently transmitted streams, where P is at least two. In one embodiment, the packet detector includes a correlation unit coupled to the single receive antenna and configured to provide a correlation function based on P acquisition fields corresponding to the P concurrently transmitted streams. Additionally, the packet detector also includes a pseudo-magnitude calculator coupled to the correlation unit and configured to calculate a packet detection metric based on the correlation function.

Expansion of the wireless communication arena is being driven by an increasing demand for wireless devices along with improvements in wireless communications platforms and systems. Users may exchange information through pagers, cellular telephones, other wireless communications and computer based products. Wireless communication provides users the benefit of exchanging personal and business information employing wireless networks such as a wireless local area network (WLAN). A WLAN provides flexibility and mobility for users by enabling access to a spectrum of communication and computer networks, including the Internet, without being restricted to a wired network.
Several standards have been established to provide uniformity and support growth in the development of wireless networks. One such standard that has been promulgated by the Institute of Electrical and Electronic Engineers (IEEE) is IEEE 802.11, which is incorporated herein by reference. IEEE 802.11 is an overarching standard that encompasses a family of specifications pertaining to packet-based wireless communication. Generally, IEEE 802.11 specifies an over-the-air interface between a wireless client and a base station or between two wireless clients.
Within the IEEE 802.11 family are several specifications, such as IEEE 802.11a/b/g, covering areas such as different transmission rates, encoding schemes and frequency bands for transmitting data wirelessly. Performance of the packet-based wireless network is dependent on reliable detection of the transmitted packets. Much work has been done in this area for a packet-based wireless receiver employing a single transmitted stream. However, when multiple concurrent transmitted streams are employed, the packet-based single receiver is typically not equipped to detect these transmitted streams reliably.
Accordingly, what is needed in the art is an improved way for a packet-based wireless receiver to reliably detect multiple, concurrent transmitted streams.

Apparatus and method of detection for a packet-based wireless receiver employing multiple, concurrent transmitted streams


A process is disclosed for coal liquefaction in which minute particles of coal in intimate contact with a hydrogenation catalyst and hydrogen arc reacted for a very short time at a temperature in excess of 400.degree. C. at a pressure of at least 1500 psi to yield over 50% liquids with a liquid to gaseous hydrocarbon ratio in excess of 8:1.

1. Field of the Invention
The invention is a short residence coal liquefaction process in which more than fifty percent of the carbon in coal is converted to liquids, while limiting production of hydrocarbon (HC) gases, resulting in high ratios of liquids/HC gases.
2. State of the Art
Structurally, bituminous coal typically consists of monocyclic and condensed aromatic and hydroaromatic rings (clusters), varying in size from a single ring to perhaps four or five rings, which are linked to each other by connecting bridges which are typically short aliphatic chains or etheric linkages. Generally, coal liquefaction processes occur in the temperature range of 400.degree. C.-500.degree. C. by rupturing the connecting bridges to form free radicals or ions. The free radicals or ions are then capped by a small entity such as hydrogen. If the free radicals are not capped, they will combine in condensation or polymerization reactions to produce large structures which will be solid at room temperature.
Prior art coal liquefaction processes can be grouped into four different types of processes: pyrolysis (including hydropyrolysis), solvent extraction, catalytic hydrogenation with a solvent, and Fischer-Tropsch which is an indirect process.
In pyrolysis processes, coal is heated to 400.degree. C. to 500.degree. C. in the absence of any reacting atmosphere or in the case of hydropyrolysis, a hydrogen atmosphere, but without an externally-applied catalyst. The connecting bridges between the condensed ring units are thermally ruptured and the free radicals which are formed are stabilized by capping with hydrogen which is abstracted from some of the structural units in the coal. The total yield of liquids and gases by pyrolysis is typically in the range of 40% by weight of the coal. The remaining 60% by weight of the coal is a solid residue known as char.
Solvent extraction processes typically involve dissolving coal in a hydrogen donor solvent and heating to 400.degree. C. to 450.degree. C. One of the more advanced solvent extraction processes is the Exxon Donor Solvent Process of Exxon Oil Company. In this process a hydrogen donor solvent is added to coal feedstock to form a slurry which is then heated to a temperature of approximately 450.degree. C. for approximately 15-20 minutes. While heating, hydrogen gas is added to the slurry.
In catalytic hydrogenation with a solvent, coal is dissolved in a hydrogen donor solvent, e.g. tetralin, to form a slurry, a hydrogenation catalyst is then introduced into the slurry and the slurry is heated to above 400.degree. C. Hydrogen addition to the coal is approximately 4% to 5% by weight and the product is a liquid and gas (C.sub.1 -C.sub.4 hydrocarbons) at room temperature. One of the most successful examples of a catalytic hydrogenation with a solvent process is the H-Coal process developed by Hydrocarbon Research, Inc.
The Fischer-Tropsch coal liquefaction technology, is the only liquefaction technology that is being utilized on a commercial scale. In the Fischer-Tropsch process, coal is gasified with oxygen and steam at a temperature which is usually above 950.degree. C., to produce carbon monoxide and hydrogen. These gases are then reacted at a temperature of approximately 430.degree. C., in the presence of an appropriate catalyst, to form gaseous and liquid hydrocarbons. In an alternative technology to produce hydrocarbons, coal is gasified to CO and H.sub.2, which are then converted, principally to methanol by well-known technology. The methanol is then converted to gasoline using the Mobil ZSM-5 catalyst.
The prior art direct coal liquefaction technologies produce large amounts of hydrocarbon (HC) gases, ratios of liquids to HC gases usually being of the order 3/1 to 4/1, with none reported greater than about 7/. Residence times of the materials (reactants plus products) in the temperature zone above 350.degree. C. are characteristically between 15 minutes and one hour. Such long exposure of the primary liquid molecules to temperatures above 350.degree. C. results in extensive thermal cracking, yielding hydrocarbon gases. Since more than half of the gases thus formed is methane, this cracking results in large consumption of hydrogen.


A positive photosensitive composition comprises                (A) a resin that has an acid decomposable repeating unit represented by formula (I) and increases its solubility in an alkali developer by action of an acid;        (B) a compound generating an acid in irradiation with actinic light or radiation;        (C) a resin that contains neither fluorine nor silicon and has a repeating unit having the predetermined structure; and        (D) a solvent,

1. Field of the Invention
The present invention relates to a positive resist composition for use in fabrication steps of semiconductors such as ICs, production of circuit boards for liquid crystals, thermal heads, etc., and lithographic steps of other photoapplications, and a pattern forming method using the composition. In particular, the invention relates to a positive resist composition suited for exposure with an immersion type projection exposure apparatus employing far ultraviolet light having a wavelength of 300 nm or less as an exposure light, and a pattern forming method using the composition.
2. Description of the Related Art
The trend toward miniaturization of semiconductor elements has lead to a decrease in the wavelength of exposure lights and an increase in the numerical aperture (NA) of projection lenses. As a result, an exposure apparatus which has an NA of 0.84 and employs an ArF excimer laser having a wavelength of 193 nm as a light source has been developed. As is generally well known, resolution and focal depth can be expressed by the following equations:(Resolution)=k1·(λ/NA)(Focal depth)=±k2·λ/NA2
wherein λ is the wavelength of the exposure light, NA is the numerical aperture of the projection lens, and k1 and k2 are coefficients relating to the process.
For achieving enhanced resolution by further reduction in the wavelength, an exposure apparatus employing an F2 excimer laser having a wavelength of 157 nm as a light source is under investigation. Since materials for the lens to be used in the exposure apparatus and materials for resists are limited strictly, however, it is very difficult to stabilize the manufacturing cost of the apparatus or material or stabilize their quality. There is hence a possibility that an exposure apparatus and a resist having sufficient performance and stability cannot be provided within a required period.
As a technique for enhancing resolution of an optical microscope, a so-called immersion method, that is, a method of filling a liquid with a high refractive index (which may hereinafter be called "immersion liquid") between the projection lens and the sample is known.
This "immersion" has the following effects. Assuming that the wavelength of the exposure light in air is λ0, the refractive index of the immersion liquid relative to that of air is n, the convergence half angle of light is θ and NA0=sin θ, the resolution and the focal depth when immersion is performed can be expressed by the following equations:(Resolution)=k1·(λ0/n)/NA0(Focal depth)=±k2·(λ0/n)/NA02
This means that the immersion produces the same effect as the use of an exposure light having a wavelength of 1/n. In other words, supposing that optical projection systems equal in NA are employed, the focal depth can be made n times larger by the immersion.
This is valid in any pattern profile. The immersion can therefore be used in combination with a super resolution technique such as the phase shift method or off axis illumination method which are being studied now.
Examples of an apparatus which has utilized the above-described effect for the transfer of fine image patterns of semiconductor devices are described in JP-A-57-153433 and the like.
Recent progress in the immersion exposure technique is reported in The Proceedings of The International Society for Optical Engineering (SPIE Proc.), 4688, 11(2002), J. Vac. Sci. Technol., B 17(1999), The Proceedings of The International Society for Optical Engineering (SPIE Proc.), 3999, 2(2000), etc. When an ArF excimer laser is used as a light source, pure water (refractive index at 193 nm: 1.44) is presumed to be most promising as an immersion liquid from the standpoints of safety in handling as well as transmittance and refractive index at 193 nm. A fluorine-containing solution is being studied as an immersion liquid for use in the exposure using an F2 excimer laser as a light source in consideration of balance between transmittance and refractive index at 157 nm. An immersion liquid satisfactory in view of environmental safety and refractive index however has not yet been found. Judging from the degree of the effect of the immersion and the maturity of resist, the immersion exposure technique will be first utilized in ArF exposure apparatuses.
Since the advent of a resist for KrF excimer laser (248 nm), chemical amplification has been employed as an image forming method of a resist for compensating a reduction in the sensitivity caused by light absorption. The image forming method, for example, using positive chemical amplification is a method of exposing a resist to light to cause decomposition of an acid generator in the exposed portions and generate an acid, subjecting the resulting resist to post-exposure bake (PEB) to utilize the acid thus generated as a reaction catalyst to convert an alkali-insoluble group into an alkali-soluble group, and removing the exposed portions by alkali development. As a chemical amplification type resist composition, resist compositions obtained by mixing two or more resins having specific structures are proposed, for example, in WO2005/003198 and JP-A-2002-303978. Although resists for ArF excimer laser using the chemical amplification mechanism are have recently become major resists, they need improvement because pattern collapse occurs when they are exposed to light through a mask with a very fine mask size.
It has been pointed out that when a chemical amplification type resist is exposed to immersion exposure, the resist layer comes into contact with the immersion liquid during exposure, resulting in deterioration of the resist layer or emission, from the resist layer, of components adversely affecting on the immersion liquid. International Publication WO 2004/068242 describes an example of a change in resist performance caused by immersing a resist for ArF exposure in water before and after exposure, while pointing out that this change is a problem in immersion exposure.
In an immersion exposure process, exposure using a scanning type immersion exposure apparatus needs movement of the immersion liquid keeping pace with the movement of a lens. If not, the exposure speed decreases, which may adversely affect on the productivity. When the immersion liquid is water, the resist film is desired to be hydrophobic and have good followability of water.
In addition, it is actually difficult to find an appropriate combination of a resin, photoacid generator, additive and solvent capable of satisfying the integrated performance of a resist. In forming fine patterns with a line width of 100 nm or less, even if the resolution performance is excellent, collapse of line patterns occurs, which may lead to defects during fabrication of a device. There is therefore a demand for overcoming this collapse of patterns and reducing line edge roughness which will otherwise disturb formation of uniform line patterns.
The term "line edge roughness" means that line patterns of a resist and edge of the interface of a substrate are shaped irregularly in a direction vertical to the line direction due to properties of the resist. Such patterns viewed from right above seem to have an edge with concavities and convexities (approximately from ± several nm to ± several tens of nm). Since these concavities and convexities are transferred to the substrate in an etching step, large concavities and convexities may deteriorate electrical properties, resulting in a reduced yield.

Positive resist composition and pattern forming method

Abstract: wherein each symbol represents a predetermined group.