High strength foamed well cement compositions and methods of cementing subterranean zones penetrated by well bores are provided. The foamed well cement compositions are basically comprised of a hydraulic cement, hydrophilic fibers, water sufficient to form a pumpable slurry, a mixture of foaming and foam stabilizing surfactants and sufficient gas to foam the slurry.

1. Field of the Invention
The present invention relates generally to cementing subterranean zones penetrated by well bores, and more particularly, to such methods whereby high strength foamed well cement compositions which are crack and shatter resistant are utilized.
2. Description of the Prior Art
Light weight foamed hydraulic cement compositions are commonly utilized in subterranean well completion and remedial operations. For example, foamed hydraulic cement compositions are used in primary cementing operations whereby pipe strings such as casings and liners are cemented in well bores. In performing primary cementing where light weight cement compositions are required to prevent fracturing of subterranean zones, light weight foamed hydraulic cement compositions are pumped into the annular space between the walls of a well bore penetrating the zones and the exterior surfaces of a pipe string disposed therein. The light weight foamed cement composition is permitted to set in the annular space thereby forming an annular sheath of hard substantially impermeable foamed cement therein. The cement sheath physically supports and positions the pipe string in the well bore and bonds the exterior surfaces of the pipe string to the walls of the well bore whereby the undesirable migration of fluids between zones or formations penetrated by the well bore is prevented.
Multi-lateral wells have recently been developed which include vertical or deviated principal well bores having one or more ancillary laterally extending well bores connected thereto. Drilling and completion equipment is available which allows multiple laterals to be drilled from a principal cased and cemented well bore. Each of the lateral well bores can include a liner cemented therein which is tied into the principal well bore. The lateral well bores can be drilled into predetermined producing formations or zones at any time in the productive life cycle of the well.
In both conventional wells having single well bores and multi-lateral wells having several well bores, the light weight foamed cement compositions utilized for cementing casings or liners in the well bores must have sufficient strength, resiliency, ductility and toughness to resist cracking or shattering as a result of pipe movements, impacts and/or shocks subsequently generated by drilling and other well operations such as perforating. Set foamed cement in wells, and particularly, a set foamed cement sheath in the annulus between a pipe string and the walls of a well bore often fails by cracking or shattering during drilling and/or perforating operations. When the set cement cracks or shatters, rubble is often produced and the seal between the pipe and the walls of the well bore is lost.
Various types of fibers have been utilized in construction cement compositions heretofore. The fibers have been formed of glass, steel, graphite, polyesters, polyamides and polyolefins. Polyolefin fibers have generally been the most preferred in that they are readily available, are low in cost and have high resistance to corrosion and degradation. Fibrillated net-shaped polyolefin fibers have been found to be particularly suitable for use in construction cement compositions because they resist being pulled out of the set cement. The fibers also function to control shrinkage cracking in the early stages of the cement setting process, and after setting, the fibers provide resiliency, ductility and toughness to the cement composition whereby it resists cracking or shattering. When cracking or shattering does occur, the fibers hold the cracked or shattered set cement together and prevent the formation of rubble.
While fibrillated polyolefin net-shaped fibers have been included in well cement compositions heretofore, problems have been encountered because the fibers have been hydrophobic and are difficult to dry blend with cement. Also, the fibers agglomerate in the dry cement when it is conveyed causing plugging to occur, and when the cement and hydrophobic fibers are combined with mixing water, the hydrophobic fibers form mats which prevent their dispersion into and throughout the cement slurry. The lack of dispersion of the fibers in the cement slurry make it difficult to pump and foam.
Thus, there are needs for improved foamed well cement compositions and methods wherein the cement compositions contain fibrillated fibers which can be easily mixed and conveyed with dry cement and subsequently dispersed in the aqueous cement slurry formed prior to pumping and foaming the slurry.
The present invention provides high strength, resilient, foamed well cement compositions and methods of cementing a subterranean zone using the compositions which meet the needs described above and overcome the deficiencies of the prior art. The compositions of the invention are basically comprised of a hydraulic cement, hydrophilic fibers present in the composition in an amount in the range of from about 0.1% to about 0.25% by weight of the cement in the composition, water present in an amount sufficient to form a pumpable slurry, a mixture of foamed and foam stabilizing surfactants and sufficient gas to foam the slurry.
The improved methods of cementing a subterranean zone penetrated by a well bore of the present invention are basically comprised of the steps of introducing a high strength, resilient, foamed cement composition into the subterranean zone by way of the well bore comprised of a hydraulic cement, hydrophilic fibers, water, a mixture of foaming and foam stabilizing surfactants and a gas. Thereafter, the foamed cement composition is allowed to set in the zone. The compositions and methods of this invention are particularly suitable for cementing a pipe string such as casing or a liner in a well bore utilizing a light weight foamed cement composition whereby the set foamed cement can withstand the formation of perforations therein as well as other impacts and shocks subsequently generated by drilling and other well operations without cracking, shattering or forming rubble.
It is, therefore, a general object of the present invention to provide high strength, resilient, foamed well cement compositions and methods of cementing subterranean zones penetrated by well bores using the cement compositions.
Other and further objects, features and advantages of the present invention will be readily apparent to those skilled in the art upon a reading of the description of preferred embodiments which follows.
The present invention provides high strength, resilient, foamed well cement compositions and methods of using the compositions for cementing subterranean zones penetrated by well bores. The high strength resilient foamed cement compositions are basically comprised of a hydraulic cement, hydrophilic fibers, water present in an amount sufficient to form a pumpable slurry, a mixture of foaming and foam stabilizing surfactants present in an amount sufficient to form and stabilize the foamed cement composition and sufficient gas to foam the slurry.
Upon setting, a foamed cement composition of this invention has high strength, resiliency, ductility and toughness whereby it resists cracking and/or shattering as a result of impacts or shocks produced in drilling or perforating operations, stresses created by pipe movements and the like. If cracking or shattering does occur, the pieces formed are held together by the hydrophilic fibers in the foamed cement composition.
A variety of hydraulic cements can be utilized in the foamed well cement compositions of this invention including those comprised of calcium, aluminum, silicon, oxygen and/or sulfur which set and harden by reaction with water. Such hydraulic cements include Portland cements, pozzolana cements, gypsum cements, high aluminum content cements, silica cements and high alkalinity cements. Portland cements are generally preferred for use in accordance with the present invention. Portland cements or the types defined and described in the API Specification For Materials And Testing For Well Cements, API Specification 10, Fifth Edition, dated Jul. 1, 1990 of the American Petroleum Institute are particularly suitable. Preferred API Portland cements include classes A, B, C, G and H, with API classes G and H being the most preferred.
While fibers formed of various materials can be utilized in accordance with the present invention, the fibers utilized must resist degradation in a hydraulic cement composition. For example, fibers formed of polyesters, polyamides and glass suffer from the disadvantage that they degrade in the presence of hydrated lime. Hydrated lime is released in a cement composition as the cement therein is hydrated. Polyolefin fibers are suitable for use in cement compositions in that polyolefin fibers do not degrade or otherwise lose their strength over time in a set cement composition. However, fibers formed from polyolefins are hydrophobic and as mentioned above, are very difficult to dry blend with hydraulic cements and disperse in water.
In accordance with the present invention, hydrophilic polyolefin fibers are included in the foamed cement compositions of this invention. The hydrophilic polyolefin fibers do not degrade in cement compositions and are readily dry mixed with cement and dispersed in the cement mixing water. Particularly suitable such hydrophilic polyolefin fibers are commercially available from the Forta Corporation of Grove City, Pa.
The preferred polyolefin fibers are polypropylene or polyethylene fibers which are in a fibrillated net configuration which maximizes the long term durability and toughness of a set cement composition including the fibers. The fibrillated net-shaped fibers function exceptionally well in preventing cracking or shattering of set cement compositions containing them, and if cracking or shattering does occur, in holding the cracked or shattered cement together, i.e., the individual pieces produced are held together by the fibers thereby preventing rubble formation.
The normally hydrophobic polyolefin fibers are converted to hydrophilic fibers by treating the hydrophobic fibers with a surface active agent. The most preferred hydrophilic fibers for use in accordance with the present invention are hydrophilic polypropylene fibrillated net-shaped fibers having lengths in the range of from about 0.5 inch to about 1.5 inches.
Generally, the hydrophilic fibers utilized are included in a foamed cement composition of this invention in an amount in the range of from about 0.1% to about 0.25% by weight of hydraulic cement in the composition, more preferably in an amount in the range of from about 0.1% to about 0.125% and most preferably about 0.125%.
The water utilized in the cement compositions of this invention can be fresh water, unsaturated aqueous salt solutions or saturated aqueous salt solutions such as brine or seawater. The water is generally present in the cement compositions in an amount in the range of from about 30% to about 100% by weight of hydraulic cement in the compositions, more preferably in an amount in the range of from about 35% to about 60%.
In order to facilitate the formation and stabilization of a foamed cement composition, at least one foaming and foam stabilizing surfactant is included in the cement compositions. While a variety of foaming and foam stabilizing surfactants can be utilized, a particularly preferred mixture of such surfactants is comprised of an ethoxylated alcohol ether sulfate of the formula H(CH2)a(OC2H4)bOSO3NH4+ wherein a is an integer in the range of from about 6 to about 10 and b is an integer in the range of from about 3 to about 10, an alkyl or alkene amidopropylbetaine having the formula Rxe2x80x94CONHCH2CH2CH2N+(CH3)2CH2CO2xe2x88x92 wherein R is a radical selected from the group of decyl, cocoyl, lauryl, cetyl and oleyl and an alkyl or alkene amidopropyldimethylamine oxide having the formula Rxe2x80x94CONHCH2CH2CH2N+(CH3)2Oxe2x88x92 wherein R is a radical selected from the group of decyl, cocoyl, lauryl, cetyl and oleyl.
The ethoxylated alcohol ether sulfate is generally present in the above described mixture in an amount in the range of from about 60 to about 64 parts by weight. The alkyl or alkene amidopropylbetaine is generally present in the mixture in an amount in the range of from about 30 to about 33 parts by weight and the alkyl or alkene amidopropyldimethylamine oxide is generally present in the additive in an amount in the range of from about 3 to about 10 parts by weight. In order to make the surfactant mixture more easily combinable with the cement slurry, water can be combined with the mixture in an amount sufficient to dissolve the surfactants.
The most preferred foaming and foam stabilizing surfactant mixture of the type described above for use in accordance with this invention is comprised of an ethoxylated alcohol ether sulfate wherein a in the formula set forth above is an integer in the range of from 6 to 10 and the ethoxylated alcohol ether sulfate is present in the surfactant mixture in an amount of about 63.3 parts by weight; the alkyl or alkene amidopropylbetaine is cocoylamidopropylbetaine and is present in the mixture in an amount of about 31.7 parts by weight and the alkyl or alkene amidopropyldimethylamine oxide is cocoylamidopropytdimethylamine oxide and is present in an amount of about 5 parts by weight.
The mixture of foaming and foam stabilizing surfactants is generally included in the foamed cement composition in an amount in the range of from about 1% to about 7.5% by volume of water in the cement composition, preferably in an amount of about 1% to about 5%.
The gas utilized for foaming the cement slurry can be air or nitrogen, with nitrogen being preferred. The gas is present in an amount sufficient to foam the slurry, generally in an amount in the range of from about 20% to about 60% by volume of the slurry.
As will be understood by those skilled in the art, the foamed well cement compositions of this invention can include a variety of conventional additives for improving or changing the properties of the foamed cement compositions. Examples of such additives include, but are not limited to, set retarding agents, fluid loss control agents, dispersing agents, set accelerating agents and formation conditioning agents.
Set retarding agents are included in the foamed cement compositions when it is necessary to extend the time in which the foamed cement compositions can be pumped so that they will not thicken or set prior to being placed at a desired location in a well. Examples of set retarding agents which can be used include, but are not limited to, lignosulfonates such as calcium and sodium lignosulfonate, organic acids such as tartaric acid and gluconic acid, copolymers of acrylic acid, maleic acid and others. The proper amount of set retarding agent required for particular conditions can be determined by conducting a xe2x80x9cthickening time testxe2x80x9d for the particular retarder and foamed cement composition. Such tests are described in the API Specification 10 mentioned above. A particularly preferred set retarder for use in accordance with the present invention is a copolymer or copolymer salt of 2-acrylamido-2-methylpropane sulfonic acid and acrylic acid. The copolymer comprises from about 60 to about 90 mole percent 2-acrylamido-2-methylpropane sulfonic acid with the balance comprising acrylic acid, and the copolymer or salt thereof preferably has an average molecular weight below about 5,000. When used, a set retarder is included in the foamed cement compositions of this invention in an amount in the range of from about 0.1% to about 2% by weight of hydraulic cement in the compositions.
Examples of fluid loss control agents which can be used include, but are not limited to, cellulose derivatives, modified polysaccharides, polyacrylamides, 2-acrylamido-2-methylpropane sulfonic acid copolymers, polyethyleneimine and the like.
An example of a dispersing agent which can be utilized is comprised of the condensation polymer product of an aliphatic ketone, an aliphatic aldehyde and a compound which introduces acid groups into the polymer. e.g., sodium bisulfite. Such a dispersant is described in U.S. Pat. No. 4,557,763 issued to George et al. on Dec. 10, 1985.
Examples of set accelerating agents which can be utilized include, but are not limited to, calcium chloride, zinc formate and triethanolamine, and examples of formation conditioning agents include, but are not limited to, potassium chloride and sodium chloride.
A particularly preferred foamed cement composition which upon setting has high strength, resiliency, ductility and toughness is comprised of Portland cement, fibrillated polyethylene hydrophilic fibers which are net-shaped present in an amount of about 0.1% to about 0.125% by weight of the cement in the composition, a mixture of foaming and foam stabilizing surfactants comprised of an ethoxylated alcohol ether sulfate present in the mixture in an amount of about 63.3 parts by weight, cocoylamidopropylbetaine present in the mixture in an amount of about 31.7 parts by weight and cocoylamidopropyldimethylamine oxide present in the mixture in an amount of about 5 parts by weight, the mixture being present in the cement composition in an amount in the range of from about 1% to about 5% by volume of the water in the composition, and sufficient gas to foam the slurry.
The improved methods of cementing in a subterranean zone penetrated by a well bore basically comprise the steps of: (a) introducing a foamed cement composition into the subterranean zone by way of the well bore, the foamed cement composition being comprised of a hydraulic cement, hydrophilic fibers, water, a foaming and foam stabilizing surfactant and a gas, and (b) allowing the foamed cement composition to set into a high strength, resilient, ductile and tough foamed cement mass in said zone.
Another improved method of cementing a pipe string in a well bore of the present invention using a light weight foam cement composition comprises the steps of: (a) preparing a foamed cement composition having a density in the range of from about 10 to about 14 pounds per gallon comprising a hydraulic cement, hydrophilic fibers, water, a mixture of foaming and foam stabilizing surfactants and a gas, (b) pumping the foamed cement composition into the annulus between the pipe string and the walls of the well bore; and (c) allowing the cement composition to set into a hlgh strength, resilient, ductile and tough foamed cement mass in said annulus.


The invention is the circuit and method for selecting a window of desired address locations to be written. A start address and a stop address activate a start and stop decoder output respectively. The active start and stop decoder output signals are rippled through start and stop ripple circuitry which enables the outputs electrically interposed between the start and stop addresses respectively. AND circuitry ensures that only the outputs interposed between the start and stop addresses are activated in addition to the start and stop decoder outputs. The activated outputs comprise the window of desired address locations to be written.

A DRAM consists of an arrangement of individual memory cells. Each memory cell comprises a capacitor capable of holding a charge and a field effect transistor, hereinafter referred to as an access transistor, for accessing the capacitor charge. The charge is referred to as a data bit and can be either a high voltage or a low voltage. Therefore, the memory has two states; often thought of as the true logic state and the complementary logic state. An arrangement of memory cells is called an array. There are two options available in a DRAM memory: a bit of data may be stored in a specific cell in the write mode, or a bit of data may be retrieved from a specific cell in the read mode. The data is transmitted on signal lines, also called digit lines, to and from the Input/Output lines, hereinafter known as I/O lines, through field effect transistors used as switching devices and called decode transistors. For each bit of data stored, its true logic state is available at the I/O lines and its complementary logic state is available at lines designated I/O*. For purposes of this discussion, I/O and I/O* lines are often referred to as just I/O lines. Therefore, each cell has two digit lines, referred to as digit line pairs.
In order to read from or write to a cell, the particular cell in question must be selected, also called addressed. Typically, the cells are arranged in the array in a configuration of intersecting rows and columns. In order to select a cell an active output from the row decoder selects a wordline appropriate to the given address. The active wordline then turns on the cell's access transistor. Next the column decoder activates and selects the desired digit line pair. For a write operation the active column decoder output activates the decode transistors to pass the data to be written from the I/O lines to the digit line pair. The data is then coupled through the access transistor to the memory cells which then store the data.
FIG. 1 represents a video display. The video display displays data stored in a memory device. The memory device is typically referred to as a video random access memory (VRAM) device. One example of a video display is a color or monochrome monitor for a personal computer. The data must be pumped to the video display by the VRAM. Each location on the video display is called a pixel.
The VRAM typically contains a DRAM memory in which pixel data is stored and a serial access memory (SAM) port. The data is usually loaded into the VRAM through a DRAM port. The pixel data is typically stored in the DRAM and supplied to the video display through a SAM port.
FIG. 1 is a simplified representation of a video display having 64 pixels. There are different methods employed to get pixel data into the DRAM memory. One method comprises computing a value representing the color of the data and computing an address for each pixel representing the data. The DRAM cycles once for each pixel. For example if the data is represented by the five pixels 1, the DRAM goes through five cycles in order to store the pixel data into the DRAM memory.
A second method can increase the speed of inputing the data into the DRAM. This method is called a block write. The block write method computes a value and an address for four pixels simultaneously. The four pixels comprise the block. The DRAM cycles once for each block of four pixels stored in the DRAM. In this method four pixels are typically accessed in each cycle. It would therefore require two cycles to implement the previous example wherein the data is defined by five pixels.
A third method of loading the data into the DRAM can increase the speed over the block write. This method is called a flash write. In a flash write all of the column addresses for a given row are loaded in one cycle. The disadvantage of the flash write is the inability to load only a portion of the column addresses for a given row.
Since a specific address is used to identify each pixel there must be a method for decoding that address. A column decoder is typically used to decode the address. A tree type column decoder is typically used as the column decoder. The tree column decoder is implemented in a NOR configuration such that when the proper inputs are low the desired column decoder output goes high.
Micron Semiconductor, Inc. distributes a "1992 DRAM Data Book," of which sections 3 and 1 are hereby incorporated by reference, containing detailed descriptions of Micron's VRAM devices. An article published in Electronic Design Nov. 23, 1989, entitled "Speed Memory, Ease Timing Requirements With VRAM Functions," by Mailloux, et al., describes many of the features used to speed data transfer to and from an associated graphics processor or microprocessor and is also incorporated by reference.


A radio receiver for a digital cellular system or the like corrects a doppler frequency shift with a simple arrangement. A phase difference of received data I,Q is corrected by generating an estimated signal EXn through estimation of the received data I,Q corresponding to transmitted data y estimated for the maximum likelihood by a maximum likelihood determination circuit 25, by detecting the branch metric BM, BM+, or BM- in which the estimated data is in phase with the received signal, or in the leading or trailing phase to the received signal, respectively, by detecting the phase difference of the received data I,Q from the estimated signal EXn based on the result of comparison of the branch metrics BM+, BM, and BM-, and by correcting the phase difference based on the result of detection of the phase difference.

1. Field of the Invention
This invention relates to a radio receiver, and is applicable for example, to a digital cellular system transmitting and receiving voice signals by coding them.
2. Description of the Related Art
Conventionally, a digital cellular system, which is a kind of radiotelephony, is designed to allow a plurality of terminals to simultaneously use one channel through a time division multiplex approach by coding voice signals for transmitting and receiving.
That is, when it is turned on, such a type of terminal sequentially scans received frequencies in a predetermined number of channels, for example, 124 channels, and detects a FCCH (frequency correction channel) which is inserted in the channel at a predetermined cycle (typically, consisting of 10 or 11 frames) in order stronger field strength, to recognize the channel including the FCCH as control channel.
Then, the terminal detects and receives a control channel assigned to the area to which it belongs.
The control channel is designed to form a time slot for transmission of various information, whereby, in the digital cellular system, each terminal receives the control channel to receive information such as information on a base station sending the control channel, information on an adjacent base station, and information for calling the terminal.
To this end, the terminal corrects the processing timing based on this FCCH.
Here, the FCCH is a synchronizing signal assigned with a bit pattern in which, when it is decoded, data of value "0" continues for a predetermined number of bits. In the digital cellular system, the bit pattern is differential coded and then GMSK (Gaussian filtered minimum shift keying) modulated for transmission.
Thus, the digital cellular system detects this FCCH, and roughly synchronizes the entire operation based on the result of this detection (that is, frame synchronization).
At the completion of frame synchronization, such a type of terminal corrects the deviation of frequency of its internal clock to the base station based on the FCCH, and then finely synchronizes the entire operation based on the subsequent predetermined reference signal.
When a state ready for receiving the control channel is thus established, the terminal receives control data sent from the base station by receiving the time slot assigned to it, and switches the transmission/receiving frequency from the control channel to a call channel, as required.
Then, the terminal transmits or receives a voice signal to or from a called station by using this call channel.
At the moment, the digital cellular system is designed to add an error correction code to the data to be transmitted, and sends out the data after performing differential coding and GMSK modulation, whereby stable communication can be assured.
Such a type of terminal may be used on a car or the like. In such a case, the terminal moves at a high speed in respect to the base station.
In this case, assuming that the relative moving speed between the terminal station and the base station is "v", and the transmission carrier frequency of the digital cellular is ".lambda.", the transmitted/received signal is doppler shifted by a frequency f.sub.dp as represented by the following equation: EQU f.sub.dp =v/.lambda. (1)
As shown in FIG. 1, if the mobile station with a terminal on board is moving in respect to the base station with an angle .alpha., the equation (1) is represented by: ##EQU1##
In this case, because the carrier frequency is selected for about 950 MHz in the digital cellular system, when the terminal moves at 250 km per hour with respect to the base station, this relationship is substituted for equation (2), thereby finding that the received signal is doppler shifted in frequency by 220 Hz at the maximum.
Such a doppler frequency shift is observed at the terminal as a deviation of the carrier frequency, resulting in a reduction of the decoding efficiency when demodulating the data and deterioration of the bit error rate for the entire terminal.
In such a case, an approach may be possible to correct the doppler shifted carrier frequency based on the above-mentioned FCCH. However, because the amount of the doppler shift varies depending on the moving speed of the terminal, the doppler shift may not be properly corrected in correspondence with the variation in the amount of shift if based on the FCCH which is intermittently inserted in the control channel.
Particularly, when the terminal moves as in the above, fading may often be caused as well. In such a case, the level and phase of the received signal simultaneously vary so that the correction of doppler shift becomes difficult.
On the other hand, a method has been proposed in which received data is stored once in a predetermined storage means, the amount of frequency shift being estimated based on the stored data, the frequency shift being corrected with the result of the estimate (The Transactions of IECE Japan, B-11, Vol.J73-8-11, No. 11, pp. 736-744, November 1990). This method causes the entire configuration to be complicated and consequently has such a problem that it can be applied to a base station, but is difficult to be applied to a terminal.
For this reason, in such a digital cellular system, the drift of the carrier frequency is specified as being 0.1 ppm or less (equivalent to a frequency of 95 Hz for the carrier frequency of 950 Hz. If the frequency doppler shifts as much as 220 Hz as in the above, not only is the bit error rate deteriorated, but it also becomes difficult to attain synchronization with the base station.
In addition, such a digital cellular system has a characteristic that the effect of doppler frequency shift becomes significant when external noise is low, in which there arises such a strange situation that the reception state is poor although sufficient field strength can be assured.


The present invention provides a novel silicone free copolymer and coating prepared therefrom. The coating which is capable of being written on effectively with both solvent-based and water-based inks is also bleedthrough resistant. A repositionable pressure sensitive adhesive note is capable of effectively adhering to the coating. The invention also provides substrates coated with the coatings and articles such as pads and rolls formed from the coated substrates.

A variety of coatings for paper have been developed to impart many different properties to the paper. These properties can include color, stiffness, receptivity to indicia, water resistance, bleedthrough resistance, release from pressure sensitive adhesives, etc.
Mertens, U.S. Pat. No. 5,154,962 describes a coating which comprises copolymers of (A) free radically polymerizable vinyl monomer, (B) polar monomer in a sufficient amount to impart a hydrated glass transitition temperature (Tg) of -15 degrees C. to 35 degrees C. and a difference of at least 20 degrees C. between the hydrated and actual Tgs, and (C) siloxane-based polymer of a type and in an amount that will impart a satisfactory release value, The coating provides a substrate with a number of properties including the ability to be effectively written on with solvent and water-based inks, the indicia remaining firmly bonded and resistant to smearing. The coating also provides bleedthrough resistance to these inks. This coating, however, provides such good release properties that repositionable pressure sensitive adhesives do not adhere to it. For example, Post-it.TM. Notes, and Post-it.TM. Tape Flags available from Minnesota Mining and Manufacturing Company ("3M") of St. Paul, Minn., which have a repositionable pressure sensitive adhesive thereon, either immediately or after a very short period of time, fall off of a vertically positioned substrate having the Mertens' coating thereon.
Thus there exists a need for a coating demonstrating ink receptivity and bleedthrough resistance, to which a repositionable pressure sensitive adhesive note can effectively adhere.

Silicon-free copolymer and bleed-through resistant, ink receptive, and adhesive receptive coatings and coated substrates prepared therefrom


A method for drawing a composite figure by combining a plurality of figures. The contours of the plurality of figures are first drawn, and thereafter the insides of the contours are successively filled with in accordance with plane filling attributes of the corresponding figures. Thus, a composite figure with unnecessary contours made to disappear at superposed portions of the figures can be obtained.

The present invention relates to an information processing device for making or preparing a document containing figures, or the like, and displaying and/or the document thus formed, and more particularly to a method for drawing figures such as animation, illustration, etc.
In order to draw figures, several kinds of figure processing software have been developed. The prior art figure processing software is to prepare basic figures such as circles, polygons, and to set their contour attributes (kinds of lines, width thereof, color thereof, etc.) and plane attributes (patterns or colors for filling plane areas, for example) and to provide shapes defining the form of the figure, thereby drawing a desired figure.
The prior art, however, has the following drawback. Referring to FIG. 1A, when the basic figures such as FIGS. 21 and 22 which show a foot are to be combined to composite FIGS. 31 to 34 as shown in FIG. 1B, the contour 31 of one basic figure overlaps the other basic figure, thus leaving an unnecessary contour 35. This is because the prior art figure processing software comprises steps such as a first step of collectively filling the contour and interior of one basic or elementary figure and thereafter a second step of filling those of the other figure. More specifically, the FIG. 21 (31, 33) drawn later hides the FIG. 22 (32, 34). The above prior art software may have a function of changing the up-and-down side relationship between the figures. However, even so, the contour 36 of the figure representing the down side remains on the FIG. 33.

Method for and apparatus for synthesizing and filling in figures having contours


A cardboard blank for constructing a first larger size food storage box and also constructing a smaller size food storage box is provided. The blank includes a first plurality of panels foldably connected to one another along a plurality of primary fold lines in order to foldably construct the larger box, and further includes a series of tearable line elements for defining removable portions of the blank and a second smaller blank. The second smaller blank includes a second plurality of panels foldably connected to one another along a plurality of secondary fold lines in order to foldably construct the smaller box.

This application claims priority benefit of Provisional application Ser. No. 60/872,427, filed May 5, 2006 (having been converted from application Ser. No. 11/381,784.)
This invention relates to a cardboard box for use in food storage, and more particularly, to a single cardboard blank that is suitable for use in the construction of cardboard boxes of different sizes.
Cardboard boxes made from foldable cardboard blanks are well known for use in packaging food and other items, such as cakes, pizza, etc. The problem is when a portion of the food item is eaten and there is a need to retain the remaining left over portion in the box for later consumption. What happens presently is that there is now a box used for storing the remaining food that is substantially empty. This creates a storage problem, since one has to reuse the large box when storing the food item in a refrigerator or pantry, where space is often at a premium. And, while the supplier of the food could provide a second small box for food storage purposes, this is rarely done, and would otherwise increase costs and inconvenience.
Accordingly, it would be desirable to provide a foldable cardboard blank that can be constructed into different size boxes in order to also accommodate the storage of left-over food or other types of items without wasting unused space in the box.


Disclosed herein are methods and devices for rapid assessment of whether a microorganism present in a sample is susceptible or resistant to a treatment.

Antibiotic resistance constitutes a major imminent threat to public health worldwide. Statistics from the CDC (U. S. Department of Health and Human Services, 2013, 114) and WHO (Organization, 2014, 257) are alarming and emphasize that the current paradigm of liberal and non-selective antibiotic use cannot continue. Emergence of resistance in Gram-negative organisms, for which there are limited treatment options, is of particular concern. Over-use of broad-spectrum antibiotics in clinics is a major contributor to the evolution and spread of drug-resistant pathogens; however, combating resistance requires diagnostic development in all settings.
To improve care, clinical laboratories require rapid tests to identify the pathogen and determine its antimicrobial susceptibility. Laboratories currently conduct identification and antimicrobial susceptibility tests (AST) via culture-based methods, which take 24-48 hours. Because the physician does not know in a proximate timeframe what organism is present, the bacterial burden, or the susceptibility of the organism to various therapeutic approaches, clinicians often choose to treat with broad spectrum (e.g. 2nd and 3rd generation) antibiotics and can even treat sub-clinical infection or false positives. Overprescribing antibiotics is most acute among complex, recurrent, and specialty cases. These include febrile children, obstructed patients, such as men with BPH, nephrolithiasis, especially those with repeated instrumentation, women with infection during pregnancy, hospitalized patients, and immune-compromised patients. In these situations, clinicians tend to treat more aggressively. Accelerating turnaround will allow clinicians to improve patient care by administering the right antimicrobial regimen without delays. Thus, to improve the problem of emerging antimicrobial resistance and to improve care, physicians in primary care settings require ultra-rapid tests to identify the pathogen and determine its antimicrobial susceptibility. What is needed, therefore, are devices and methods for rapidly and accurately diagnosing infection and antimicrobial resistance or susceptibility.

Microfluidic measurements of the response of an organism to a drug


The invention of the present patent application provides, a histamine-hyperproductive animal, which is a non-human animal or progeny thereof obtained by ontogenesis of totipotent cell transfected with a polynucleotide encoding histidine decarboxylase and has the above polynucleotide in the cellular chromosome to produce histamine at a high level in the somatic cells. Thus, analysis of the pathogenesis and pathological consequence in various disorders associated with histamine in human as well as development of therapeutic techniques and remedies for these disorders will be developed.

Histamine is a member of autacoids acting in the living body, abundant in the skin, lung, digestive organs, and so on, which is released in allergy and anaphylaxis and associated with the onset of urticaria or inflammation or hematopoiesis. In the gastric mucosa, it has been found that histamine is involved in the generation of gastric ulcers because it is present in the enterochromaffin cells to play an important role in promoting secretion of gastric juice.
Thus, since histamine is involved in a variety of human disorders and alteration of physical condition, elucidation of the mechanism of its action is essential for development of the therapeutics and remedies used in histamine-related diseases. Since these diseases or change of physical condition arise in the context of i various tissues or organs in the body, it is indispensable to study the effect of histamine in vivo using a model animal.
In this viewpoint, the inventors of the present application have already invented knockout animals (animals lackng in histamine) in which th gene for histamine synthetase has been knocked out, and filed as the Japanese Patent Application no. 11-246315 (1999). However, animals expressing histamine in excess have not yet been known.
Therefore, it has eagerly been desired to develop a model animal system by which a variety of symptoms in animal individuals in the excess state of histamine could be analyzed systematically. It has also been expected that such model animals might be a powerful tool for developing remedies used in treatment of a variety of disorders associated with histamine.
The invention was made in view of the above-mentioned situation, aiming for providing animals with high histamine productivity, capable of producing histamine in excess in the body.

Animals with high histamine productivity

Japan Science and Technology Corporation


An intake system for a supercharged engine can include a blow-off passage provides communication between the upstream side of the throttle valve and the upstream side of a supercharger. A blow-off valve opens and closes the blow-off passage. The blow-off valve can be configured to open and close based upon pressure on the downstream side of the throttle valve. The present intake system can further comprise a first conduit providing communication between the upstream side of the throttle valve and the blow-off valve, a second conduit providing communication between the downstream side of the throttle valve and the blow-off valve, and a solenoid valve for switching between the first and second conduits.

1. Field of the Inventions
The present inventions relate to intake systems for supercharged engines.
2. Description of the Related Art
Supercharged engines are conventionally used in small boats and vehicles such as automobiles. Intake systems in such engines are generally adapted to supply the engine with air that is compressed by the supercharger, which is disposed in an intake passage. Some intake systems for supercharged engines are configured with a blow-off passage including a blow-off valve disposed in the intake passage. The blow-off passage and blow-off valve are generally configured to prevent an excessive increase in pressure within the intake passage. (See Japanese Patent Application JP-A-Hei 10-89079, for example).
In such intake systems for supercharged engines, a throttle valve is provided in the intake passage between the engine and the supercharger, and the blow-off passage connects the upstream side of the throttle valve and the upstream side of the supercharger. The blow-off valve, which is located in the blow-off passage, opens when the pressure on the upstream side of the throttle valve exceeds the pressure on the downstream side, and exceeds a predetermined value. When the blow-off valve opens, the air on the upstream side of the throttle valve, namely, the air between the throttle valve and the supercharger, returns to the upstream side of the supercharger through the blow-off passage. The blow-off valve and the blow-off passage thereby prevent damage to a compressor of the supercharger that could be caused by excessive pressure produced during abrupt deceleration.


Processing of out-of-order data transfers is facilitated in computing environments that enable data to be directly transferred between a host bus adapter (or other adapter) and a system without first staging the data in hardware disposed between the host bus adapter and the system. An address to be used in the data transfer is determined, in real-time, by efficiently locating an entry in an address data structure that includes the address to be used in the data transfer.

One or more aspects of the invention relate, in general, to the transfer of data to and from memory of a computing environment, and in particular, to the processing of out-of-order data transfers within the computing environment.
In some computing environments, such as those that include System z® servers offered by International Business Machines Corporation, data is transferred from memory of a computing system to input/output devices, and from the input/output devices to memory using one or more host bus adapters (HBAs). The host bus adapters are attached to the system through hardware which isolates the host bus adapters from the system. This hardware provides isolation of the unchecked host bus adapter from the system, so as to maintain reliability, availability and serviceability (RAS) for the system.
With this type of configuration, all data flowing to/from the system is temporarily stored in the hardware, and then, moved from the hardware to its intended destination. Thus, a store and forward delay is incurred for each data transfer.

This patent is subject to a terminal disclaimer.

Facilitating processing of out-of-order data transfers

INTERNATIONAL BUSINESS MACHINES CORPORATION


A method for measuring table sag of a table may include utilizing images of an unloaded table and a loaded table, plotting pixel values for a range of pixels for each image within a particular column, identifying a pixel within each plot that has a highest pixel value, calculating a difference between the identified pixel row numbers, and converting the difference into a measurement of table sag. A storage medium encoded with machine-readable computer program code for measuring table sag of a table may include instructions for causing a computer to implement the method. A computer for use in an imaging system may utilize digital images for the measurement of table sag and an imaging system may include such a computer.

This invention relates generally to a method and system for measuring table sag, and more particularly, this invention relates to an improved method and system for measuring sag of a loaded table used in imaging systems.
In a computed tomography (CT) system, an x-ray source projects a fan-shaped beam that is collimated to lie within an X-Y plane of a Cartesian coordinate system, termed the "imaging plane." The x-ray beam passes through the object being imaged, such as a medical patient, and impinges upon a multi-row multi-column detector array. The detector array comprises a plurality of detector elements. The intensity of the transmitted radiation is dependent upon the attenuation of the x-ray beam by the object and each detector element of the detector array produces a separate electrical signal that is a measurement of the beam attenuation. The attenuation measurements from all of the detector elements are acquired separately to produce the transmission profile.
The source and detector array in a conventional CT system are rotated on a gantry within the imaging plane around the object so that the angle at which the x-ray beam intersects the object constantly changes. A group of x-ray attenuation measurements from the detector array at a given angle is referred to as a "view" and a "scan" of the object comprises a set of views made at different angular orientations during one revolution of both the x-ray source and the detector. In an axial scan, the projection data is processed to construct an image that corresponds to a two-dimensional slice taken through the object. One method for reconstructing an image from a set of projection data is referred to as the filtered back projection technique. This process converts the attenuation measurements from a scan into integers called "CT numbers" or "Hounsfield units", which are used to control the brightness of the corresponding pixel on a cathode ray tube display.
A detector array in a CT imaging system comprises a plurality of detector modules. Each detector module has a scintillator array optically coupled to a semiconductor photodiode array. The scintillator array emits light in response to receiving x-rays. The photodiode array detects light output by the scintillator array and generates electrical signals responsive thereto.
When acquiring CT images, it is important to have precise patient and image registration. For radiation treatment (RT) planning purposes, it is desired to scan the patient on the CT scanner in the exact position that will be used for radiation treatment. Third party laser lights are often installed and calibrated in order to assist with this patient positioning. The 3rd party laser lights are usually installed a substantial distance (˜0.6 m) from the scanning plane and a noticeable amount of vertical table sag can occur between the table position used to align the patient with the third party lights and the table position used while acquiring the CT scan. This table sag, if unaccounted for, could result in errors in the radiation treatment. Table sag distances as large as 6 mm have been measured at clinical sites.
U.S. Pat. No. 6,561,695 addresses several patient and image registration inaccuracies, including table sag. However, the method requires special equipment to be installed in tables. Thus, previous methods have used additional hardware that gives geometrical information including table sag and special tables must be purchased and installed for conducting such methods.

Method and system for measuring table sag


The present invention discloses a system and method for predicting the dryness of clothing articles in a clothes dryer 10. In one embodiment of this invention, the clothes dryer 10 uses a temperature sensor 52, a phase angle sensor 54, and a humidity sensor 56 to generate signal representations of the temperature of the clothing articles, the motor phase angle, and the humidity of the heated air in the duct, respectively. A controller 58 receives the signal representations and determines a feature vector. A neural network 168 uses the feature vector to predict a percentage of moisture content and a degree of dryness of the clothing articles in the clothes dryer 10. In another embodiment of this invention, the clothes dryer uses a combination of sensors to predicts a percentage of moisture content and a degree of dryness of the clothing articles.

Typically, an appliance for drying articles such as a clothes dryer for drying clothing articles uses an open control loop to dry the articles. The open control loop allows a user to set a drying time for drying the clothing articles. Setting the drying time requires an estimation by the user of when the clothing articles will be dry and generally results in the articles being either over-heated or under-heated. Over-heating of clothing articles results in unnecessary longer drying times, higher energy consumption, and the potential for damaging the articles. On the other hand, under-heating causes great inconvenience because the user has to reset the drying time and wait again for the clothing articles to be dry. Since the drying results provided by the open control loop are unpredictable, further clothes processing such as ironing is hindered. Accordingly, there is a need for a clothes dryer that can predict the moisture content and degree of dryness of the articles in order to facilitate further clothes processing.

System and method for predicting the dryness of clothing articles


A method for forming a contact in a semiconductor device includes opening a contact hole exposing a surface of a substrate, performing a first post treatment to form a rough portion at a bottom surface of the contact hole, and performing a second post treatment. The first post treatment includes using a fluorocarbon gas and the second post treatment includes using a nitrogen trifluoride (NF3) gas.

The present invention relates to a method for fabricating a semiconductor device, and more particularly, to a method for forming a contact in a semiconductor device with increased contact area and reduced leakage current.
As patterns in highly integrated memory devices below 0.100 μm become micronized, contact hole spacing has decreased. Accordingly, a high aspect ratio has caused margins to rapidly decrease, and thus, spacing distance between lines also have decreased. The source/drain contact resistance (Rc) increases substantially when the hole spacing and the spacing distance between lines decreases.
FIGS. 1A and 1B illustrate cross-sectional views showing a typical method for forming a contact in a semiconductor device.
Referring to FIG. 1A, a plurality of gate patterns are formed over a substrate 11. Each gate pattern includes a gate insulation layer 12, a gate electrode 13, and a gate hard mask layer 14. Cell spacers 15 are formed over the gate patterns. In more detail, a cell spacer layer is formed over the substrate 11 and the gate patterns. The cell spacer layer may include a nitride-based layer. An insulation layer is formed over the cell spacer layer to sufficiently gap-fill between the gate patterns. An etching process for forming a landing plug contact is performed. That is, the insulation layer is etched until the etching stops at the cell spacer layer to form trenches. This creates patterned insulation layers 16.
A buffer oxide layer is formed over the resultant substrate structure. The buffer oxide layer is formed with poor step coverage. That is, the buffer oxide layer is formed to have a small thickness over upper surfaces of the substrate 11 and sidewalls of the gate patterns and have a large thickness over an upper portion of the gate patterns, having an overhang structure. An etch-back process is performed on the buffer oxide layer to form contact holes 17 exposing the upper surfaces of the substrate 11 between the gate patterns. This creates patterned buffer oxide layers 18. During the etch-back process, portions of the cell spacer layer over the upper surfaces of the substrate 11 are also etched away. This creates the cell spacers 15. Since the etch-back process of the buffer oxide layer includes a dry etching process using plasma, the substrate damage 19 is often generated by plasma ions during the etch-back process.
Referring to FIG. 1B, a post treatment is performed to remove the substrate damage 19. The post treatment includes performing an etching process referred to as a light etch treatment (LET). Such post treatment often generates a substrate depression 20.
The typical method increases the depth of the substrate depression 20 by the LET process which reduces contact resistance of the source/drain contacts, by increasing the contact area. However, the increased depth may cause leakage current, and refresh may be deteriorated. Also, although a certain depth in the substrate depression 20 is generally needed to control the cell threshold voltage (Vth) and the refresh, this is typically not enough to increase the contact resistance value. Thus, a method for forming a contact that can maintain a certain depth of the substrate depression and improve contact resistance may be necessary.

Method for forming a roughened contact in a semiconductor device


An image forming apparatus includes a light source to emit a laser beam; a resonant scanning mirror, including a reflection surface to reflect the laser beam emitted from the light source, to scan the reflected laser beam by oscillating the reflection surface; at least one detector to detect the reflected laser beam during the scanning of the reflected laser beam, and generate a synchronizing signal each time the reflected laser beam is detected; and at least one light selection unit to restrict a path over which the reflected laser beam is incident on the at least one detector to a predetermined path.

1. Field of the Invention
Aspects of the invention relate to an image forming apparatus with a laser scanning device and a method of aligning the laser scanning device, and more particularly to an image forming apparatus equipped with a laser scanning device capable of performing bidirectional laser scanning using a resonant scanning mirror, and a method of aligning the laser scanning device.
2. Description of the Related Art
In general, an image forming apparatus is a device that prints out black-and-white images or color images onto a recording medium such as paper in accordance with image signals. Examples of such an image forming apparatus include a laser printer, an inkjet printer, a photocopier, a digital multifunction printer, a facsimile machine, and the like. The various image forming apparatuses create an image generally by an electrophotographic method or an inkjet method. In the electrophotographic method, an electrostatic latent image is formed on a photoconductive medium by scanning the photoconductive medium with a laser beam. Then, developer is adhered to the photoconductive medium corresponding to the electrostatic latent image, and a thus-formed developer image is transferred to a recording medium, thereby forming a final image. The inkjet method forms an image by spraying liquid ink on a recording medium in accordance with image signals.
An electrophotographic image forming apparatus forms a desired image using the following process. First, a surface of the photoconductive medium is charged to a predetermined electric potential. A laser beam is emitted onto the surface of the charged photoconductive medium to thereby form an electrostatic latent image. A visible image is formed by adhering powder-type developer to the electrostatic latent image. Next, the visible image formed by the developer is transferred to a recording medium and fixed on the recording medium by heat and pressure.
The electrophotographic image forming apparatus is equipped with a laser scanning device that forms the electrostatic latent image by scanning the photoconductive medium with a laser beam in accordance with image signals. The laser scanning device includes a light source that generates the laser beam according to the image signals, a collimator lens that forms a parallel laser beam from the laser beam emitted from the light source with respect to an optical axis, a cylinder lens that converts the parallel laser beam emerging from the collimator lens to a linear laser beam that is horizontal with respect to a vertical scanning direction, a polygon mirror that reflects the linear laser beam emerging from the cylinder lens and scans the reflected laser beam in a horizontal scanning direction, an fθ lens that focuses the reflected laser beam scanned by the polygon mirror on the photoconductive medium by compensating for an aberration of the scanned laser beam, and a detector that detects the scanned laser beam and generates a synchronizing signal each time the scanned laser beam is detected. These component parts are all mounted in a single frame as one integrated unit.
Recently, the tendency has been to increase the rotation speed of the polygon mirror to improve a printing speed of the image forming apparatus. Therefore, the cost to achieve this has been increasing.
To this end, there has been introduced a method of employing a flat mirror having a reflection surface, which is relatively inexpensive, instead of the polygon mirror rotating at a high speed, as disclosed in U.S. Patent Application Publication No. 2005-0275710 published on Dec. 15, 2005.
According to the disclosed method, a photoconductive medium is scanned in accordance with image signals in a forward direction and then a backward direction using a resonant scanning mirror in which the reflection surface that reflects the laser beam is oscillated at a resonant frequency.
In order to accurately form the electrostatic latent image on the photoconductive medium according to the image signals, all component parts of a laser scanning device including the resonant scanning mirror, including an incident optical system including the collimator lens and the cylinder lens, must be precisely and stably mounted on a housing.
When the resonant scanning mirror is used to deflect the laser beam, synchronizing signals are generated using different detectors corresponding to the different scanning directions, that is, the forward scanning direction and the backward scanning direction. Thus, the positions of the detectors mounted on the housing as well as the position of the resonant scanning mirror oscillating at the resonant frequency to deflect the laser beam must be strictly controlled.
For accurate generation of the synchronizing signals, the plurality of detectors generating the synchronizing signals and the resonant scanning mirror must be placed at correct positions. If an error occurs in mounting the resonant scanning mirror on the housing during assembly, the resonant scanning mirror may not be synchronized properly, or the scanning may be performed according to incorrectly generated synchronizing signals. Accordingly, the ability to check the position of the resonant scanning mirror after assembly is required.

Image forming apparatus with laser scanning device and method of aligning the laser scanning device


A recording method suitable for high-density recording is provided. When information is recorded on an optical recording medium with irradiation of a write pulse of a laser beam, a length corresponding to 7 T is set to be equal to or less than the spot diameter λ/NA of the laser beam where T is one recording clock cycle, λ is a wavelength of the laser beam, and NA is a numerical aperture of the objective lens, and a specified mark with a length corresponding to 3 T or more is recorded by a single write pulse.

1. Field of the Invention
The present invention relates to a method and apparatus for recording information on an optical recording medium, and in particular, to a method for irradiation the optical recording medium with a laser beam using pulse control during recording.
2. Description of the Related Art
Various standards of optical recording media such as CD-R/RWs and DVD-R/RWs, which allow the user to record information, have been widely used. Meanwhile, the demand for large storage capacity in these types of optical recording media is increasing year by year. In order to meet this demand, new standards such as Blu-ray discs (BDs) have been proposed. In the Blu-ray Disc standard, an optical disc apparatus uses a data recording/reproduction laser beam with a narrow beam spot diameter. Specifically, the apparatus uses a laser beam with a shorter wavelength λ and a higher numerical aperture (NA) objective lens for condensing the laser beam. As a result, an information recording layer of the Blu-ray disc can store as much data as 25 GB or greater.
In general, rewritable optical recording media, which allow rewriting data, use a recording film made of a phase change material. Specifically, heating the recording film by irradiation with a laser beam and appropriately controlling the cooling rate thereafter can selectively form an amorphous region and a crystal region in the film, and the difference in reflectivity between these regions achieves recording information. When doing so, the laser beam is required to be set under various conditions such as a write power level (Pw) with a high energy, an erase power level (Pe) with a middle energy, and a bias power level (Pb) with a low energy. Recording information on the optical recording medium is performed by pulse irradiation of the laser beam with any selected one of the three power levels.
In order to form a mark on an optical recording medium, a write pulse at the write power level and a bias pulse at the bias power level are alternately irradiated. The recording film is irradiated with the write pulse, so that the irradiated region is heated to its melting point or more. When the same region is then irradiated with the bias pulse, the area is rapidly cooled and thus is turned to an amorphous recording mark. Therefore, if the set of the write pulse and the bias pulse is continuously applied, it is possible to form a long recording mark.
Irradiating the optical recording medium with a laser beam with the erase power level erases a mark having been recorded on the optical recording medium. The recording film is irradiated with the laser beam with the erase level, so that the irradiated region is heated to its crystallization temperature or more. The whole irradiated region, including the amorphous region (mark), is then crystallized by natural cooling, so that the recording mark is erased.
Accordingly, recording information is performed in such a manner that a region where a mark is to be formed is continuously irradiated alternately with the write pulse and the bias pulse according to the length of the mark, and a region where a space is to be formed is irradiated with a laser beam with the erase power level according to the length of the space. Such a power modulation method is called a write strategy.
Increasing the recording density as well as the write speed causes an edge shift on the recording mark. For example, when a long recording mark such as 4 T or 6 T is formed by a plurality of write pulses, too high write speed makes it hard to ensure sufficient cooling time, which corresponds to the width of the bias pulse between the write pulses. This poor cooling causes a part of the mark to recrystallize, and thus may degrade the recording quality. Therefore, in order to increase the recording accuracy, accurate control of the laser pulse is required, and therefore, there are various approaches.
For example, Japanese Patent Application Laid-Open No. 2005-71516 discloses that, when writing each mark, the width of a bias pulse which is inserted into the end of the mark is varied depending on the length of the mark so as to reduce the jitter of a production signal. Moreover, when writing each mark, a bias pulse is inserted additionally into the top of the mark so as to delay the rising of the first write pulse. Similarly, Japanese Patent Application Laid-Open Nos. 2005-63586 and 2002-288830 disclose that at the beginning of writing a mark, a pulse with a power level lower than that of an erase pulse is inserted so as to prevent the top area of the mark from recrystallizing.
Japanese Patent Application Laid-Open No. 2001-273638 discloses that, when forming a mark with a 4 T length or more, a bias pulse is inserted so as to prevent the mark from recrystallizing. The publication of Japanese Patent No. 2707774 discloses that, when forming a long mark by, for example, three write pulses or more, a bias pulse is inserted either before a top write pulse or after an end write pulse so as to sharpen the leading or trailing edge of the mark.
However, a further increase in storage capacity increases the recording density of the information recording layer, thereby degrading the quality of the reproduction signal. This makes it hard to identify a bit using zero-crossing detection. At the same time, this makes it hard to determine the signal quality using the jitter. Therefore, a Partial Response, Maximum Likelihood (PRML) detection scheme may be used for signal reproduction. However, if the PRML detection scheme is adopted, then errors associated with marks corresponding to 2 T or 3 T are likely to increase. In other words, errors are likely to occur when the recording pattern is made of a series of relatively short marks. All the patent documents mentioned above are to perform a precise pulse control of all marks or relatively long marks. Therefore, the application of such a control without any modification is unable to fully perform high density recording.
Moreover, when high-speed recording is to be conducted on a large capacity (high density) medium exceeding 30 GB, it is necessary that the recording film be made of a material whose crystallization speed is extremely fast. However, if low-speed recording is conducted on such an optical recording medium, the recording accuracy will significantly deteriorate.

Recording method for optical recording medium and recording apparatus


A delta modulation method and system is provided for processing signals in a digital communications system. The method quantizes an input signal using a tri-state quantizer into a quantized value selected from a set of three different quantized values including a low value, a middle value, and a high value. The selection of the quantized value is based on a comparison between the input signal and a predicted signal of a corresponding sampling period. The method generates from the quantized value an output signal representative of the input signal, determines a predicted signal of the next sampling period, and then feeds the predicted signal of next sampling period back to the tri-state quantizer.

1. Field of the Invention
The present invention relates generally to the field of signal processing involving signal conversion, modulation, encoding, decoding, and/or compression, and more particularly to delta modulation methods for converting and modulating an analog signal to a digital signal.
2. Description of the Prior Art
Delta modulation (DM) is an analog-to-digital signal conversion in which the analog signal is approximated with a series of segments, and each segment of the approximated signal is then compared to the original analog wave to determine the increase or decrease in relative amplitude. The decision process for establishing the state of successive bits is determined by this comparison, and only the change of information is retained, stored or sent. Specifically, conventional delta modulation describes a status of the signal in a quantized binary fashion. The status is either "1" or "0", representing either an increase or decrease of the present status of the signal when compared to the previous status of the signal. Only an increase or decrease of the signal amplitude from the previous sample is retained. An output signal is then reconstructed (decoded) through integration (summing up) of the consecutive statuses of the signal to represent the origin of signal. The ingenuity of delta modulation technique lies in its taking advantage of the inherent data redundancy to greatly reduce the amount of data without losing much information. For this reason, delta modulation is also referred to as delta compression. Since its inception in the early 1950s, delta modulation technique has proven to be a highly advantageous signal modulation method when compared to other pulse communications systems. It is now often the de facto method used in a broader range of applications of signal processing, compression, transmitting, and data streaming. Although its most common use is for processing audio signals, delta modulation technique is not limited to such signals. In principle, delta modulation technique can be applied to any type of signal that can be digitized, including but not limited to audio signals, image signals and video signals.
Delta modulation used in communications systems usually has a differential input circuit having one input connected to a source of input signals (typically analog signals) to be encoded, and a second input to receive a feedback signal. The system also has a decoder connected to a decision circuit. The output of the decision circuit acts as the output of the delta modulation, but is additionally applied to the second input of the differential input circuit as the feedback signal to facilitate a comparison operation.
In general, the performance of a delta modulation apparatus is affected by sampling rate and choices of quantization steps. Delta modulation typically exhibits a maximum tracing slope for an input signal to be encoded. The tracing slope is limited by the product of the magnitude of the quantization step of the decision circuit and the frequency of the sampling pulses applied. For a given sampling rate (the frequency of the sampling pulses), a steeper slope of the signal (corresponding to either rapid increase or decrease of the signal amplitude) requires a greater quantization step. On the other hand, a large quantization step may produce high-level noises when applied in relatively smoother regions of the signal. To reduce this problem, adaptive delta modulation techniques, such as Continuous Variable Step Delta Modulation (CVSD), are used. These techniques use dynamically adaptive quantization steps to suit for signals having both steep slopes and smoother regions.
Despite the advancements in the delta modulation technique, further improvement is desired. One area for improvement is signal/noise ratio. For applications involving data compression, which is one of the areas where delta modulation is particularly useful, there is a constant demand for higher signal/noise ratio at a given sampling rate, or for maintaining the same signal/noise ratio at a lower sampling rate. This is because sampling rate is directly proportional to the size of data that needs to be stored or transmitted in a communications system. For narrowband implementations, for example, bandwidth is typically limited to 50 kHz or below, often in the range of 12.5 kHz–25 kHz, due to the limited transmission capacity of the system. A bandwidth of 12.5 kHz–25 kHz would mean that data rate is limited to 8 kbps–16 kbps or lower. These implementations include wireless voice communications systems such as wireless networks and walkie-talkie devices, and digital telephone systems. There is a significant need for improving performance at relatively low data rate for this type of narrowband implementations.


An intake silencer is designed as a broadband silencer for noises causes by intake of combustion air into internal combustion engines. To achieve the broadband effect, an axial sequence of resonator chambers with different volumes is formed by partitions which extend transversely to the intake pipe in a resonator that surrounds the intake pipe Each resonator chamber communicates through openings in the wall of the intake pipe with the air sucked through the intake pipe. By matching the open surface area of the openings, the thickness of the wall of the intake pipe in the area of the openings and the volume of the resonator chambers, a continuous broadband silencing may be set even over a wide frequency range, the range of practical interest in the present application extending combustion from to 1 to 10 kHz. In motor vehicles with an internal combustion engine, a supercharger and an air charge cooler, the intake silencer is advantageously arranged in the pressure pipe joint of the supercharger, directly behind it or integrated therein, but in any case at a certain distance upstream of the air charge cooler.

An intake muffler of the above species is known from German patent document 743,418 A. FIG. 1 of this document shows, immediately after the intake-air filter, a muffler system wherein the intake pipe is fitted with wall apertures directly behind the dust-filter cartridge and is enclosed by an insulating material. After this segment, as seen in the direction of flow, the intake pipe comprises an axial sequence of apertures arrayed in an annular manner. Each aperture communicates with a chamber externally enclosing the intake pipe. The intake-air acoustic waves passing through any particular set of apertures are deflected by bell-shaped sleeves so that they move in counterflow to the intake-pipe airflow into the enclosing chamber and onto the radially directed chamber base. The chamber base acts as a reflector. As a result, the back-reflected acoustic waves moving towards the set of intake apertures effectively lower the acoustic admittance of the apertures in the intake pipe such that effectively coupled intake-muffling is achieved even at frequencies in the lower-frequency range.
Accordingly the state of the art disclosed in the '418 German reference discloses intake muffling by resonance-coupling of a reflection damper. Dampers of this construction are suitable only at low frequencies, for instance to dampen 2nd-order engine vibrations, since they comprise only a single resonance frequency per chamber. Moreover, they entail bulk due to the configuration of each reflecting chamber and the number of chambers required to achieve at least a moderately broad band in the intake muffler.
Another muffler for internal-combustion engines is known from German patent document 580,923 A in the form of an intake muffler or backfire damper. Boreholes determining resonance wavelengths in the exhaust pipe are enclosed by a sleeve because of the higher pressure in the exhaust pipe. This sleeve degrades the damping of the exhaust muffler.
Another intake muffler is known from U.S. Pat. 4,350,223. This intake muffler is inserted into a conduit consisting of a corrugated hose connecting an ambient-air suction aperture in the vehicle body to an inlet stub of the air filter. This intake muffler dampens air noise generated at the suction zone within a narrow frequency band straddling the resonance frequency of the resonator.
German offenlegungsschrift 32 34 634 A1 discloses a resonator of a similar construction which is integrated directly ahead of the filter inlet stub. Two rows of apertures connect the filter inlet stub acting as the intake pipe of the intake muffler to the inside of the enclosing resonator. Both rows of apertures are arrayed in such manner that they cause .lambda./2 and .lambda./4 damping relative to the natural frequency of the inlet stub. While muffler effectiveness is improved thereby, its bandwidth is not.
German patent document 35 31 353 C2 discloses an intake muffler "plugged" with damping material and integrated into the inlet stub of a booster-air cooling device to be used in an internal combustion engine fitted with a booster (supercharger).
The intake mufflers of the state of the art illustrated above effectively dampen only within a narrow frequency band. Moreover, the muffler plugged with damping material are suitable only for systems having moderate superpressure. Mufflers damped with damping materials are unsuitable for a supercharger intake conduit.
It is known from International Patent Application WO 92/14922 A1 to construct a broadband intake muffler by connecting in parallel variously elongated side pipe resonators. Even though these resonators are made partly compact using labyrinths, this intake muffler is nevertheless still sufficiently bulky as to preclude practical use in automotive engineering.
It is already known, from European patent document EP 242 797 B1 as regards diffusers and from German offenlegungsschrift 41 34 408 A1 as regards a bypass resonator to construct intake mufflers with an effective broad bandwidth while averting bulk by using flaps and valves to produce matched damping systems which can be adjusted in relation to engine speed.
These systems incur the drawbacks of requiring a more or less complex regulating means, and additional installation space is required than for the initially described in-line resonators.
This state of the intake muffling art is faced with increasing ecological demands that motor vehicles shall reduce fuel consumption significantly. In particular, highly effective superchargers are inevitable to implement such goals.
The turbochargers presently used for such purposes operate at rotor speeds of nearly 200,000 rpm. Obviously turbochargers meeting such high requirements can practically remain economical only by trading off manufacturing tolerances. As a result, high acoustic radiation arises from such turbochargers, in particular the typical turbocharger "whistling" in the approximate frequency range of 2 to 4 kHz. In the process too, the boosting steps per se in the intake conduit also generate broadband radiated noise in the 4-6 kHz band, which is called "hissing".
Consequently, environmentally friendly motor vehicles shall require broadband absorbers of airborne noise in the foreseeable future in order to act as intake mufflers in motor vehicles using internal combustion engines charged by a supercharger and making it possible to effectively dampen the frequency band of 2 to 6 kHz.
Accordingly, it is an object of the invention to create a generally applicable broadband airborne-noise absorber which is also appropriate as an intake muffler for an internal combustion engine and which, while of minimal bulk that can be easily matched to specific requirements, allows effective damping of airborne noise uniformly over a broad frequency band. In particular, such an intake muffler shall be able to dampen noises acoustically generated and radiated by turbochargers in the approximate frequency band of 2 to 6 kHz to such an extent that for practical purposes they no longer can be heard either inside or outside the vehicle.


A navigation system includes a GPS receiver for receiving radio waves transmitted from multiple GPS satellites and producing a measured position, an error-range setting unit for setting an estimated error range in which a measured position at the time of current positioning by the GPS receiver is included, a relative-position determining unit, and a position correcting unit. The relative-position determining unit and the position correcting unit correct the measured position by using an actual measured position, when the actual measured position produced by the GPS receiver at the current positioning time is in the estimated error range. The relative-position determining unit and the position correcting unit correct the measured position in accordance with a relative positional relationship between the actual measured position and the estimated error range, when the actual measured position is out of the estimated error range.

1. Field of the Invention
The present invention relates to a navigation system that corrects a measured position obtained by using a GPS receiver, and that uses the corrected measured position.
2. Description of the Related Art
It has been conventionally known that a measured position obtained by using a GPS receiver varies due to error factors, such as multipaths, and a navigation system that corrects the measured position so as to reduce an influence caused by the error is known (refer to, e.g., Japanese Unexamined Patent Application Publication No. 8-313278, pages 5 to 8 and FIGS. 1 to 3). The navigation system estimates the current measured position based on the previous measured position to set an estimated error range. When the current measured position is in the estimated error range, the navigation system uses the actual measured position, and when the current measured position is out of the estimated error range, the navigation system uses the estimated measured position. Thus, when error in the measured position using GPS is large, the navigation system can reduce the influence.
In the identified Publication, when the current measured position is out of the estimated error range, the estimated measured position is used. Since the estimated error range is set centering at the estimated measured position, the estimated measured position is inevitably set at the center of the estimated error range. Thus, for example, even when the estimated measured position is slightly out of the estimated error range, the estimated measured position is used without considering the slight difference. Thus, there is a problem in that error is increased. The Publication also discloses a method for correcting the measured position by adding the estimated measured position and the actual measured position through predetermined weighting. In this method, even when the measured position is expected to be in the estimated error range, the corrected measured position may be out of the estimated error range (in particular, when the actual measured position is greatly out of the estimated error range). Thus, there is a problem in that error can be increased. For example, since it is considered that the accuracies of a velocity and a travel direction detected with a GPS receiver are high, the possibility that an error-free measured position is in the estimated error range is considerably increased when the current measured position is assumed to be correct.


A method for calculating a high-altitude power curve for a wind turbine is provided, the method including the steps of determining a cp-λ curve for a predetermined blade pitch angle of said wind turbine; calculating a first power curve without power limit based on the cp-λ curve; and calculating the high-altitude power curve with power limit from said first power curve, thereby using a site air density.

The present invention relates to a method for predicting a power curve for a wind turbine, especially to a method for obtaining a power curve adapted for high altitude operation of a wind turbine. Furthermore, the present invention is directed to a control strategy utilizing such power curve and to a wind turbine in which such control strategy is implemented.
Wind turbines capture kinetic energy from the wind and convert it into electrical power. Since wind turbines can be designed as stand-alone or island solutions, they are especially suited to supply electric power to remote areas. For example, such areas may be located in mountainous regions or elevated plains, i.e. at high altitude. Due to their elevated location, wind turbines installed at those sites encounter a lower air density compared to sea level. The lower air density causes significant deviations from the "normal" operation at sea level. In particular, the power curve of the wind turbines is different for operation in high altitude. Since the power curve is used to predict the annual power output of the turbines, the power curve deviation may adversely affect the quality of power output predictions. Also, the power curve is used as a basis for the control strategy implemented in the turbine controller. Accordingly, turbine control will not be optimal if the implemented power curve does not correctly reflect the actual behavior of the turbine.
For the above reasons, a power curve correction for high altitudes was developed which is known to those skilled in the art as the IEC 61400-12 standard for air density normalization. The IEC standard describes a method how the sea level power curve of a pitch-regulated wind turbine can be corrected for lower air density at high-altitude sites. However, it turned out overtime that still the power curves corrected according to standard IEC 61400-12, edition 1998, do not correctly reflect the turbine behavior and, typically, overrate the power production in the partial load operation range of the wind turbine.

Method for predicting a power curve for a wind turbine


A fin-channel recess-gate MISFET has a fin channel including a first portion configured by a portion of a silicon substrate and a second portion configured by a pair of silicon layers selectively grown on the silicon substrate. The first portion is disposed below the recess of the recess gate and above an isolation film of a STI structure formed on the silicon substrate. The second portion is disposed above the recess of the recess gate.

(a) Field of the Invention
The present invention relates to a semiconductor device including a fin-channel recess-gate MISFET (metal-insulator-semiconductor field-effect-transistor) and a method for manufacturing the semiconductor device including the fin-channel recess-gate MISFET.
(b) Description of the Related Art
Recently, new models of MISFET including a fin-channel MISFET having a fin channel and a recess-gate MISFET having a recess gate are expected to achieve a finer pattern size in a semiconductor device. The techniques for the fin-channel MISFET and recess-gate MISFET may be applied to a single MISFET to achieve a fin-channel recess-gate MISFET. FIGS. 7A to 11A show consecutive steps of a conceivable (or comparative) process for manufacturing a semiconductor device including such a fin-channel recess-gate MISFET. FIGS. 7B to 11B are sectional views taken along line B-B in FIGS. 7A to 11A, respectively, and FIG. 10C is a sectional view taken along line C-C in FIG. 10A.
The structure shown in FIGS. 7A and 7B is formed by the following steps. An array of dielectric film patterns 12, one of which is shown in those drawings, are formed on a silicon substrate 11 by a photolithographic and dry etching technique using a photoresist mask pattern. Subsequently, a trench 18 is formed on the surface region of the silicon substrate 11 by a dry etching technique using the dielectric film patterns 12 as an etching mask, followed by depositing an isolation film 13 within the trench 18 to form a shallow trench isolation (STI) structure. The height (h13) of the dielectric film 12 as measured from the bottom of the trench 18 of the STI structure to the top of the dielectric film 12 is set at a specific value in consideration of the dimensions of the fin channel and recess gate.
For example, the height h13 of the isolation film 13 is set at 400 nm assuming that the thickness of dielectric film patterns 12 is 100 nm, the height of fin channel is 100 nm, the depth of gate trench is 100 nm, and the depth of shallow trench 18 needed for isolation between adjacent device regions is 100 nm in the final structure of MISFETs. The isolation film 13 and shallow trench 18 are then polished using a CMP (chemical-mechanical-polishing) technique using the dielectric film patterns 12 as a stopper, thereby forming the structure shown in FIGS. 7A and 7B.
Subsequently, a photoresist pattern 21 having an opening in the central area of the dielectric film patterns 12 is formed by a photolithographic technique. The width d2 of the opening in the dielectric film patterns 12 is set at 50 nm. The dielectric film patterns 12 are then etched using the photoresist pattern 21 as an etching mask, to form an opening 19 in the dielectric film patterns 12 for exposing therethrough the silicon substrate 11. The resultant structure is shown FIGS. 8A and 8B.
Subsequently, the photoresist pattern 21 is removed, and a dry etching process is performed to the silicon substrate 11 by using the dielectric film patterns 12 as an etching mask, to thereby form a recess 23 for the gate electrode within the silicon substrate 11. The depth h2′ of the recess 23 is set at 100 nm, for example. A wet etching process is then conducted to the dielectric film patterns 12 and the isolation film 13 of the STI structure. At this stage, the amount of wet etching is controlled so that the dielectric film patterns 12 are entirely removed and the height h 13′ of the isolation film 13 remaining after the wet etching is 100 nm, for example. The resultant structure is shown in FIGS. 9A and 9B.
Thereafter, a gate insulation film 14 is formed on the exposed surface of the silicon substrate 11 by using a thermal oxidation technique, for example, followed by deposition of a gate electrode material. The thickness of the deposited gate electrode material is larger than the width d2 of the recess 23 in the silicon substrates 11, whereby the entire depth of the recess 23 is filled with the gate electrode material. Thereafter, the gate electrode material is polished using a CMP technique for planarization of the top surface thereof. The top surface of the gate electrode material has a height of h5 with respect to the top surface of the silicon substrate 11. The gate electrode material is then patterned to form a gate electrode (gate electrode line) 15 having a depth d5 of 70 nm, for example, which is larger than the width d2 of the recess 23, whereby both the edges of the gate electrode (i.e., gate electrode line) 15 are outside the recess 23. This structure is shown in FIGS. 10A and 10B, and also shown in FIG. 10C which is taken along line C-C in FIG. 10A, i.e., along the extending direction of the gate electrode line 15. The gate electrode 15 encircles the fin channel 20 at the top and side surfaces of the fin channel 20, as shown in FIG. 10C.
An insulation film is then formed on the entire surface including the surface of the gate electrode 15, followed by etch-back thereof to form a sidewall insulation film 16 on the sidewall of the gate electrode 15. An interlevel dielectric film and contact plugs penetrating therethrough are then formed to complete the structure of MISFETs, as shown in FIGS. 11A and 11B.
The fin-channel MISFET is described in Patent Publications Nos. JP-2004-533728A, -2005-236305A and -2006-13521A, for example. The recess-gate MISFET is described in a literature "Symposium on VLSI Technology Digest of Technical Papers", P 11-12, 2003 presented by J. Y. Kim et al.
In the comparative process for manufacturing the fin-channel recess-gate MISFET as described above, there is a problem in that the trench 18 of the STI structure during embedding the isolation film 13 within the trench 18 has a large aspect ratio to thereby incur occurrence of a void within the isolation film 13. The void, if formed in the isolation film 13, degrades the characteristics of the isolation film 13 and may increase the leakage current of the MISFET.

Semiconductor device including a fin-channel recess-gate MISFET


A driving mass of an integrated microelectromechanical structure is moved with a rotary motion about an axis of rotation, and a first sensing mass is connected to the driving mass via elastic supporting elements so as to perform a first detection movement in a presence of a first external stress. The driving mass is anchored to an anchorage arranged along the axis of rotation by elastic anchorage elements. An opening is provided within the driving mass and the first sensing mass is arranged within the opening. The elastic supporting and anchorage elements render the first sensing mass fixed to the driving mass in the rotary motion, and substantially decoupled from the driving mass in the first detection movement. A second sensing mass is connected to the driving mass so as to perform a second detection movement in a presence of a second external stress. A first movement is a rotation about an axis lying in a plane, and a second movement is a linear movement along an axis of the plane.

1. Field of the Invention
The present invention relates to a microelectromechanical integrated sensor structure having a rotary driving motion. In particular, in the following description reference will be made to a gyroscope (whether uniaxial, biaxial, or triaxial), which can possibly operate as an accelerometer (whether uniaxial, biaxial, or triaxial).
2. Description of the Related Art
As is known, microprocessing techniques enable formation of microelectromechanical structures or systems (the so-called MEMS) within layers of semiconductor material, which have been deposited (for example, in the case of a layer of polycrystalline silicon) or grown (for example, in the case of an epitaxial layer) on top of sacrificial layers, which are removed by chemical etching. Inertial sensors, accelerometers and gyroscopes obtained with said technology are encountering an increasing success, for example in the automotive field, in inertial navigation, or in the sector of portable devices.
In particular, integrated semiconductor gyroscopes are known, which are made with MEMS technology. Said gyroscopes operate according to the theorem of relative accelerations, exploiting Coriolis acceleration. When an angular velocity is imparted on a movable mass that is moving with a linear velocity, the movable mass "feels" an apparent force, referred to as Coriolis force, which determines a displacement thereof in a direction perpendicular to the direction of the linear velocity and to the axis of rotation. The movable mass is supported via springs that enable a displacement thereof in the direction of the apparent force. According to Hooke's law, said displacement is proportional to the apparent force, and consequently, from the displacement of the movable mass, it is possible to detect the Coriolis force and the angular velocity that has generated it. The displacement of the movable mass can, for example, be detected capacitively, by measuring, in resonance conditions, the variations in capacitance caused by the movement of movable electrodes, integrally fixed to the movable mass and comb-fingered to fixed electrodes.
Examples of embodiment of integrated gyroscopes of a MEMS type are described in EP-A-1 253 399 and EP-A-1 365 211, filed in the name of the present applicant, which relate to gyroscopes with a rectilinear driving motion, or else in WO 02/103364 and U.S. Pat. No. 6,062,082, which relate to gyroscopes with rotary driving motion.
In general, gyroscopes of a known type are not completely satisfactory for what concerns simplicity of production, reduction in dimensions, efficiency, and immunity to disturbance. In addition, microelectromechanical structures of a known type enable a limited configurability. Furthermore, rejection of external interference (for example, due to spurious linear or angular accelerations) is critical.

Microelectromechanical integrated sensor structure with rotary driving motion