A reaction vessel support device for mounting on a magnetic stirrer hotplate. The modular device comprises a base unit capable of positioning and seating at the reaction hotplate, and an insert formed non-integrally with the base unit comprising a reaction vessel receiving portion capable of seating and locating about a portion of a reaction vessel. At any one time, the base unit is capable of accommodating a plurality of different shaped and sized inserts each insert being configured to seat and support a specific reaction vessel of particular shape and size. The device therefore serves as a magnetic stirrer hotplate adapter.

(1) Field of the Invention
The present invention relates to a device for positioning at a reaction plate, the device being configured to seat a reaction vessel at the reaction plate.
(2) Description of the Related Art
Laboratory based chemical reactions are typically carried out in a reaction vessel and where the reaction medium is liquid based, the reaction vessel is typically a round bottomed glass flask, commonly borosilicate, which is sold under the brand name Pyrex® by Corning of Corning, N.Y.
In order to drive the reaction heat is supplied to the reaction vessel which in turn transfers the heat to the reaction medium. The common bunsen burner represents one of the more primitive sources of heat used in the laboratory to heat reaction vessels. A further example is the commonly used oil bath in which the oil is heated by heating elements located within the bath. Oil baths have found particular use where elevated temperatures are required.
When used within a laboratory environment, the naked flame of the bunsen burner is particularly hazardous as it may serve as an ignition source for flammable solids, liquids or vapour. Oil baths pose a number of significant hazards. Firstly, the viscosity of the oil decreases when heated and spillage or splattering of the heated oil commonly results in skin burns or provides an ignition source. However, one of the more frequent accidents associated with oil baths stems from overheating of the oil resulting in ignition or explosion.
Hotplates and hotplate stirrers have been available for sometime and represent significantly safer laboratory heat sources. Hotplate stirrers operate by generating a rotating electromagnetic field in the region of the hotplate which induces a rotation effect on a magnetised stirring bar positioned within the liquid to be stirred. Resistance heating elements positioned in contact with the hotplate provide a means for heating the substantially planar working surface. Heat is supplied from the hotplate either directly to the reaction vessel, in contact with the hotplate, or via a liquid, typically an oil bath, positioned on the hotplate working surface. When used in combination with an oil bath, the significant risks posed to laboratory personnel remerge. Where a liquid/oil bath is not used the limited surface contact area between the planar hotplate and the curved flask provides for inefficient heat transfer and a limited heating effect.
One known device includes an adapter block constructed from aluminum or stainless steel for positioning over a stirrer hotplate. The adapter block comprises a plurality of recesses, each recess being configured to seat and partially house a reaction vessel. As a result of the extended surface contact area between the adapter block and reaction vessel, heat generated by the hotplate is efficiently transferred to the reaction medium within the reaction vessel.
The known device described above is specifically designed for parallel synthesis involving the simultaneous heating and stirring of multiple reaction vessels positioned outside the perimeter of the hotplate. This known adapter block is specifically designed for use with test tube or boiling tube type reaction vessels having a substantially elongate shape. Additionally, as the reaction vessels are located outside the perimeter of the reaction plate the rotational effect imparted to the magnetised stirring bar within each reaction vessel is reduced. This may be a particular problem where the reaction medium is particularly viscous.


A process for treating bacteria laden effluent from a sewage treatment digester to condition the effluent for release into the environment includes the steps of thoroughly mixing the effluent with a bactericide, conveying the mixed effluent to a reaction zone to completely kill any bacteria entrained in the waste water to provide a substantially bacteria free effluent, mixing an oxidant with the bacteria free effluent, maintaining the mixture for a sufficient time to permit substantially complete oxidation and neutralization of entrained bactericide, and discharging the treated effluent into the environment. In an alternative procedure the treated effluent is passed through a neutralizing filtration step to neutralize any active bactericide before the effluent is discharged to the environment.

A serious problem all over the world is handling waste water resulting from sewage treatment facilities. Cities are becoming larger and larger and accordingly are generating increasing quantities of sewage waste water that must be properly treated before it is released to the environment. A standard technique for treating municipal sewage is to pass the sewage into a digester system wherein the sewage is reacted with bacteria to break down the organic components. After complete reaction with bacteria the result under ideal condition is a relatively clear effluent, the non-digestible components such as dirt, sand and so forth settling out as sludge that is permitted to dry and then disposed of. Such sludge makes good landfill and is otherwise readily disposed of.
A more serious problem is disposition of the resultant water effluent after treatment in a digester. While the organic action in a digester usually results in substantially complete decomposition of organic matter, nevertheless the resultant effluent can contain bacteria that can be harmful to aquatic life as well as animals and humans. Standard procedures for treating municipal waste in digesters frequently result in production of effluent that contains coliforms, that is, E-coli type bacteria that can be a serious environmental hazard.
The presently used procedure for treating the effluent from a municipal waste digester is to inject chlorine into the effluent for discharge to the environment. While chlorine is successful in killing any remaining bacteria and particularly killing coliforms, the chlorine itself is becoming an environmental problem. Because of the huge amounts of municipal waste effluent that is treated by chlorine that is constantly released to the environment, including into the atmosphere, some authorities are beginning to impose restrictions on the amount of chlorine that can be contained within discharged effluent. Putting it another way, some governmental agencies have enacted specifications defining effluent suitable for environmental discharge to substantially eliminate the use of chlorine. Most plants which put effluent back into the environment are to dechlorinate the effluent first. This doubles the cost of disinfecting the effluent and then dechlorinating.
This invention provides a method of treating sewage waste water that results from a sewage digester system to make the sewage waste water acceptable for discharge into the environment, such as a lake, stream, ocean or the like, and which does not include entrained chlorine.
Others have provided systems and processes for treating municipal waste in an effort to provide an effluent discharge that is environmentally acceptable. As an example, U.S. Pat. No. 4,188,289 that issued Feb. 12, 1980 entitled "Process For Purification Of Sanitary Water", Ferdinand Besik, inventor, teaches a relatively complex system employing a series of various biochemical and chemical reactions including the use of a fluidized reactions that take place in a fluidized non-biodegradable suspended solid solution. The system includes chemical oxidation for providing removal of remaining impurities and the killing of bacteria and viruses. However, the system involves a relatively complex sequence of steps so that the system would be inheritantly difficult to monitor and control.
U.S. Pat. No. 4,204,955 issued May 27, 1980 is entitled "System For Pollution Suppression", Edward T. Armstrong, inventor. This patent teaches a process in which air, oxygen-enriched gas, or oxygen itself is ozonated and the system operates in a way to provide increased concentration of ozone that is fed to a fluid dispersing system containing a flat plate orifice which creates a down stream vena contracta. The addition of the ozonated gas into the vena contracta produces an efficient mixing device, however the overall system is complex and the equipment required to carry out the process is therefore relatively expensive compared with the simplicity and economy of operation of the process that is to be revealed in this disclosure.
U.S. Pat. No. 4,370,306 issued Jan. 25, 1983 is entitled "Process For Separation of Traces of Gaseous Contaminants From Waste Gases By Chemical Absorption", Kurt Kirchner and Wolfgang Litzenburger, inventors. The process disclosed in this patent is useful for separation of traces of gaseous contaminants or pollutants that are based on halogens, sulfur or other compounds. The process that is taught in this patent is not helpful in finding a way to avoid the commonly employed use of chlorine to kill bacteria that is typically entrained in a sewage treatment discharge effluent and therefore does not solve the problem that is solved by the present invention.
U.S. Pat. No. 4,416,786 issued Nov. 22, 1983 is entitled "Process For The Treatment of Continuous Waste Water Streams Having Changing Contents of Different Oxidizable Materials With Hydrogen Peroxide", Helmut Knorre, Joachim Fischer and Klaus Stutzel, inventors. This patent is concerned with a process for the treatment of a continuous waste water stream having a varying content of oxidizable materials wherein the oxidizable materials are treated with hydrogen peroxide for the purpose of detoxification and reduction of the chemical oxygen demand and biological oxygen demand. This patent further includes a method of regulating the rate of administration of hydrogen peroxide. The system is relatively complex and does not achieve the economy, efficiency and simplicity of the system of this invention for treating waste water.
For additional background information relating to efforts of others to improve waste water treatment, the disclosures contained in the following United States patents are helpful.
______________________________________ U.S. PAT. NO. INVENTOR TITLE ______________________________________ 4,612,124 Escrig Method of Sewage Treatment 5,037,624 Tom et aI Composition, Apparatus and Process, For Sorption of Gaseous Compounds of Group II-VII Elements 5,132,383 Larson et al Copolymers of 3- Methacryloyloxy-2- Hydroxypropyl Trimethylammonium Chloride Monomer and Vinyl Monomer 5,167,806 Wang et al Gas Dissolving and Releasing Liquid Treatment System 5,240,600 Wang et al Water and Wastewater Treatment System 5,433,858 Elliott, Jr. Treatment of Hazardous Waste Water 5,470,480 Gray et al Process For Treating Waste Water Effluent 5,503,720 Teske Process For The Quantitative Determination of Electrochemically Reducible or Oxidizable Substances, Particularly Peracetic Acid Mixed With Other Oxidizing Substances ______________________________________


An apparatus, method and system is provided for generating an optical code where a portion of the information stored in the optical code is encrypted prior to being stored in the optical code. In accordance with an aspect of the invention, a portion of the information stored in the optical code is encrypted to prevent the fraudulent creation of an optical code or use of the optical code on an item it was not created for or intended to be used with.

Any discussion of prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.
Point of sale (POS) terminals are used throughout the retail industry to process purchase transactions. A POS terminal typically includes a personal computer (PC) core in a chassis, one or more displays, an optical code scanner with weigh scale, a cash drawer, a magnetic stripe reader (MSR), keyboard and a printer. The POS terminals can either be self-service or assisted service.
The optical code scanner includes an imaging scanner and may also include a laser scanner. The two scanners use different technologies to independently read optical codes such as barcodes presented to the scanner. The laser scanner reads a barcode by sweeping a beam of laser light across a barcode, capturing data representing the reflected laser light, and then processing the captured data to recover information encoded in the barcode. An imaging scanner reads a barcode by capturing a complete image of the barcode and then processing the image to recover information encoded in the barcode.
Optical codes, such as barcodes, are generally affixed to or printed on items being presented to a POS terminal for purchase. The optical codes include information about the item they are affixed to or printed on. This information can include identification information for the item and the weight of the item if it is prepackaged and sold by weight. Some retailers have experienced a type of fraud where a person presents a false optical code, sometimes on a cell phone, instead of scanning the actual item being presented to the POS terminal for purchase. The false optical code has weight information that either matches or is approximately equal to the actual item so a weigh scale of POS terminal does not detect the substitution.
Therefore, to prevent the above fraud, as well as other related frauds, there is a need to determine if an optical code that is being presented to a POS terminal for scanning corresponds to the item being presented for purchase.

Apparatus, method and system for generating an optical code with authenticatable information


A system includes an encoding module and a laser driver module. The encoding module is configured to encode a data stream. The laser driver module is configured to convert the encoded data stream into a write signal including one or more edges. The write signal is output to an optical writer. The laser driver module is configured to adjust an actual position at which the optical writer writes a first edge of the one or more edges on an optical storage medium away from a desired position for the first edge. The adjustment is made based on (i) a first preceding edge position, (ii) a first following edge position, (iii) a second preceding edge position or a second following edge position, and (iv) a third preceding edge position or a third following edge position. The first edge corresponds to a beginning of a mark edge of the write signal.

The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Optical recording devices are used to record information, such as music, movies, pictures, data, etc., on recordable media. Examples of recordable media are compact discs (CDs), digital versatile discs (DVDs), high density/high definition DVDs and Blu-ray Discs (BDs). In order to record information onto recordable media, a recording device typically tracks the location of a laser beam on the recordable media.
FIGS. 1A-1B respectively illustrate partial cross-sectional views of examples of recordable mediums 10-A, 10-B. The recordable mediums 10-A, 10-B have lands 12 and grooves 14, which are formed on one or more recording layers 16 of one or more main substrates 18. The main substrates 18 may be adhered via an adhesive layer 20 to dummy substrates 22, as shown.
The lands 12 and grooves 14 refer to physical structures of the recording layer 16 that are adjacent each other but that have different associated depths. For example, the grooves 14 have a greater associated depth than the lands 12. Sample land depths D1 and sample groove depths D2 are shown. The depths may be measured relative to a disk outer surface 24 and are equal to a fraction of an optical wavelength of a laser beam. The lands 12 and grooves 14 provide servo information for positioning of a laser beam spot on a disc. The lands 12 and grooves 14 also provide reflected beam signal modulation that is detected and used for tracking.
Standards, such as DVD+/−R and DVD+/−RW, require recording only over grooves. An alternative standard, referred to as DVD-RAM, requires recording over both land and groove structures. In DVD+/−R and DVD+/−RW recording, the lands 12 and grooves 14 typically form a continuous spiral. In DVD-RAM recording, the lands 12 alternate with the grooves 14 to form a continuous spiral.
FIG. 2 illustrates a conventional optical DVD drive system 50. The optical DVD drive system 50 includes a laser source 52, such as a laser diode, that emits a laser beam 54. The laser source 52 may be part of an optical read/write assembly (ORW) 56. The ORW 56 includes a collimator lens 58, a polarizing beam splitter 60, a quarter wave plate 62, and an objective lens 64. The laser beam 54 is collimated by the collimator lens 58 and passed through the polarizing beam splitter 60. The laser beam 54 is received by the quarter wave plate 62 from the beam splitter 60 and is focused via the objective lens 64. The laser beam 54 may be radially displaced across tracks of the optical storage medium 68 through movement of the ORW 56 via a sled motor 66. The laser beam 54 is moved while the optical storage medium 68 is rotated about a spindle axis 69. The laser beam 54 is shaped and focused to form a spot over the land/groove structures of an optical storage medium 68 via lens actuators 70.
The light from the laser beam 54 reflects off the optical storage medium 68 and is thus directed back into the ORW 56. The reflected light, represented by dashed line 72, is redirected by the beam splitter 60. An astigmatic focus lens 76 focuses the reflected light into a spot over a photo-detector integrated circuit (PDIC) 74. Although not shown, additional photo-detectors may be used to detect other diffracted light beams, which are also not shown.
Referring now to FIG. 3, an exemplary bit-stream of write channel data is presented. Data that is to be written to optical storage media may first be encoded using techniques such as cyclic redundancy check (CRC), error-correcting code (ECC), Reed-Solomon coding, and/or interleaving. Alternatively, 8-to-14 modulation (EFM) may be used to encode the data to be stored on an optical storage medium. The encoded data stream may then be sent to a laser driver unit, which converts the data stream into a series of electrical pulses that are used to record the data onto the optical storage medium.
An exemplary channel bit-stream is represented as waveform 80. The waveform 80 contains one bit for every time period (T). The interval where the waveform 80 is high may be referred to as a space 82a, 82b. The intervals where the waveform 80 is low may be referred to as marks 84a-84c. Marks may be represented on the optical storage media as areas of low reflectivity (pits), amorphous domains, or any other type of form that can be sensed by the optical system. Spaces may be represented as areas of high reflectivity between marks. These reflectivities may be created by a laser beam, as is known in the art.
A typical optical reader, for example a DVD player, has a light spot that is approximately 9T wide. In other words, a typical optical reader detects the reflectivity of an area on the optical storage medium that is nine time periods long. Thus, marks or spaces of a length less than 9T may be difficult to distinguish from adjacent spaces or marks. In most encoding schemes, optical readers are generally designed to detect edges of a waveform (e.g., edges 85 of waveform 80) in order to decode the data therein.
Depending on the parameters of the optical storage media, and the binary encoding scheme employed, the length of marks and spaces may be constrained. For example, in the EFM encoding technique, the smallest length of a mark or space is 3T and the longest length of a mark or space is 11T. A laser driver, based on the information in the data stream, determines the correct power and time duration for operating a laser to create marks (e.g., marks 84a-84c). These marks 84a-84c, in combination with spaces 82a, 82b, are then detected or read by an optical reader. The goal of the laser driver is to create marks and spaces such that the optical reader will detect the stored data correctly. In accordance with this goal, a laser driver typically includes a translation module, such as a laser table, that dictates how data is to be stored on an optical storage medium.
Among other functions, a laser table will direct the laser driver to position a mark based on the immediately preceding space length and the length of the mark to be written. Thus, the actual physical beginning of a mark edge 85 may need to be adjusted from a desired position (that is, the position corresponding substantially to the intended data stream) in order for the position that is detected to correspond with the desired position of the signal to be stored. In other words, the optical reader will detect an edge 85 in a position that may not correspond to the actual physical position of the edge as written on the optical storage medium. This phenomenon is referred to as inter-symbol interference or ISI and causes the waveform that is output from the optical reader to differ from the physical marks and spaces that are stored on the optical storage medium. ISI contributes to jitter and other causes of error in data retrieval.

System and method for storing data to an optical recording device


Blends of epoxy-functional silicone polymers with vinyl ether monomers and alkylphenol compounds plus an effective amount of a suitable iodonium photocatalyst provide a radiation-curable silicone release coating composition.

This invention relates to improved ultraviolet light curable silicone release coating compositions. More particularly, it relates to novel additive blends of alkylphenols and alkyl vinyl ethers, which, when added to epoxysilicone polymers, provide for superior miscibility of polar onium salt photocatalysts in the epoxysilicone medium, and provide for superior release of the resulting photocured silicone coating from acrylic adhesives laminated thereto.
Silicone coating compositions are used for many applications including release coatings, or adhesive coatings, designed to permit release of aggressive adhesives without denigration of the adhesive properties due to contact with the silicone surface. Other silicone coatings well known to those versed in the art include protective coatings and conformal coatings. Such coatings have often been applied to various substrates as dispersions in solvents such as low boiling aromatic and aliphatic organic compounds or as emulsions dispersed in water. In such cases it is necessary to apply considerable heat to both remove the dispersing agent and to accelerate crosslinking (curing) of the silicone that has been applied to the substrate. Application of silicone without solvent or water dispersing agents is a desirable improvement of the art in that removal of volatile organic solvent requires environmentally compliant technology that adds cost to the coating process without otherwise benefiting the coating process. Similarly, elimination of a thermal cure step in favor of a low temperature radiation crosslinking process permits use of film, plastic or other thin gauge substrate material for the silicone release coating which would otherwise be ruled out because such substrates cannot accommodate the heat required for conventional silicone release coating crosslinking.
Silicone compositions have long been in use for rendering surfaces non-adherent to materials which would otherwise adhere thereto. Epoxy-functional polydimethylsiloxanes (PDMS), when combined with compatible iodonium cationic type photocatalysts, are well known to those skilled in the art to be useful UV curable silicone release coatings. Such combinations of organofunctional silicone polymers and lipophilic iodonium photocatalysts have been taught in U.S. Pat. No. 4,279,717 and many other subsequent patents. Such coatings based on cationic photocurable epoxy-silicones have been shown to be readily coatable to thin, defect-free continuous films when applied to smooth paper or plastic film liners using 3 roll offset gravure or multiroll liquid film splitting techniques, and these coatings are quickly crosslinked by exposure to focused ultraviolet light to create low surface energy adhesive surfaces capable of release of organic pressure sensitive adhesives (PSA). A drawback to the cationic epoxysilicone based photocurable release coating systems has been their inability to provide long term stable release from commonly used aggressive acrylic PSA""s, particularly if the adhesive is laminated to the silicone coating in-line, that is, as part of the converting process. While the precise cause of this performance deficiency is not established, it is thought that a significant post-cure of the epoxysilicone coating takes place which, when occurring in the laminate with the acrylic PSA, leads to chemical interactions of the silicone surface with the acrylic PSA which in turn leads to unstable release and even a lock-up of the silicone surface with the PSA. It is therefore clear that providing a means by which a photocured epoxysilicone release coating can consistently give low (premium) release of aggressive acrylic adhesives as a function of laminate aging is highly desirable.
The absence of solvent from a coating composition reduces the energy needed for crosslinking as well as the need for pollution abatement. But the absence of solvent leads to problems insofar as silicone release coatings are non-polar viscous materials that are immiscible with many polar additives including ""onium type cationic photocatalysts. Another problem associated with solvent-free silicone coatings is that the high viscosity associated with solvent free compositions is unsuited for many cost-effective coating techniques including direct gravure or indirect gravure coating. Such coating equipment is used for pattern coating of silicone to produce complex double release constructions and other specialty products. Vinyl ether monomers such as dodecylvinyl ether and the bis-vinyl ether of 1,4-cyclohexanedimethanol have been shown to be useful reactive diluents for photocurable epoxysilicone release coatings, capable of efficient reduction of viscosity and enhancement of photocure, as taught by Eckberg et al in U.S. Pat. No. 5,650,453. However, the presence of vinyl ethers in the cured epoxysilicone release coating gives rise to unstable release of the silicone coated liner from most acrylic and rubber based adhesives. Alkylphenols such as 4-dodecylphenol (DDP), in blends with certain alkanediols, have been shown to be effective reactive diluents for cationic photocure epoxysilicone release systems, as taught by Descorcie et al in U.S. Pat. No. 5,010,118. Also, the use of DDP or other alkylphenols in such cases for the enhanced miscibility of alkoxy-substituted bis-aryl iodonium and tris-phenyl sulfonium hexafluoroantimonates has been published. Phenol-substituted epoxysilicone terpolymers have been described as controlled release additives for UV epoxysilicone systems in Riding et al, U.S. Pat. No. 4,952,657.
The present invention is based on the discovery that certain specific combinations of additives are miscible with photocurable silicone compositions and also act as compatibilizing agents for polar ""onium type cationic photocatalysts which are often incompletely miscible with nonpolar organofunctional silicones and which, unexpectedly, provide dramatic improvement in the stability of release of the resultant UV cured silicone coating from aggressive acrylic adhesives. The present invention provides for photocurable silicone release coating compositions that are efficiently photo-crosslinked, readily applied to film, paper, and glassine substrates, and which provide exceptionally stable release from aggressive adhesives. The compositions of the instant invention provide for a curable additive for catatonically photocurable silicone polymers, said additive selected from a first group consisting of vinyl ether monomers and a second group selected from a group of alkylphenol compounds.
The present invention therefore provides for an ultraviolet light or electron beam curable silicone coating composition comprising:
a) An epoxy functional silicone selected from the group consisting of:
MDxDEyQzTuDRfjM
MEDxDEyQzTuDRfjME
MEDxDEyQzTuDRfjM
And mixtures thereof; and where:
M=(CH3)3SiO1/2
ME=(C6H9O(CH2)2)(CH3)2SiO1/2
D=(CH3)2SiO2/2
DE=(C6H9O)(CH2)2(CH3)SiO2/2
DRf=(CF3CH2CH2)(CH3)SiO2/2
Q=SiO4/2
T=(CH3)SiO3/2
where j, x,y,z, and u are positive integers and j, z, and u may be zero and wherein said epoxy-functional silicone has a viscosity ranging from about 20 to about 100000 centistokes at 25xc2x0 C. And, if preferred, a polydimethylsiloxane chainstopped with (poly)(carbinol) group-containing trialkylsiloxy species of the general formula:
MBOHDvMBOH
Where D is as defined above, and MBOH=R1R2R3SiO1/2, with R1, R2, and R3 each monovalent radicals and each independently selected from the group consisting of hydrogen, trifluoropropyl, monovalent hydrocarbon radicals, and (HO-alkyl)nxe2x80x94 radicals such that each MBOH chainstopper unit includes at least one, and preferable more than one, (HO-alkyl) group;
b) an unsaturated ether compound selected from the group consisting of:
CH2xe2x95x90CHxe2x80x94Oxe2x80x94(CH2)11CH3
(CH2xe2x95x90CHxe2x80x94Oxe2x80x94CH2)2xe2x80x94(C6H10)
CH2xe2x95x90CHxe2x80x94Oxe2x80x94(CHa-bRxe2x80x2bCH2xe2x80x94Oxe2x80x94)cxe2x80x94CHxe2x95x90CH2
(CH2xe2x95x90CHxe2x80x94Oxe2x80x94CH2)(HOCH2)(C6H10)
CH2(CH2COOCH2xe2x80x94C6H10xe2x80x94CH2OCHxe2x95x90CH2)2
(CH2xe2x95x90CHxe2x80x94Oxe2x80x94(CH2)4OOC)2(C6H4)
CF3(CF2)dxe2x80x94Oxe2x80x94CHxe2x95x90CH2
Where a is two, b is zero or 1, c and d are integers, and Rxe2x80x2 is an alkyl group selected from CH3, C2H5, C3H7, and C4H9;
c) an alkylphenol selected from the group described by:
Rwxe2x80x94C6Hi(OH)k, where R=saturated or unsaturated aliphatic substituent of from 1 to about 20 carbon atoms, halogenated aliphatic groups, alkylaryl groups, and where i=4xe2x88x92(w+k);
d) an effective amount of a bis(alkylphenyl)iodonium salt photocatalyst, said photocatalyst being selected from the salts of the groups of acids consisting of hexafluoroantimononic acid, hexafluorophosphosphoric acid, hexafluoroarsenic acid, tetrafluoroboric acid, triflic acid, tetra(perfluorophenyl)boric acid and mixtures thereof.
The subscripts on the various components of the epoxy-functional silicones may be varied within the constraints listed such that viscosity and other properties are within a desired range. The present invention further provides for curable silicone compositions that include unsaturated ethers selected from the group listed in b) above, plus alkylphenols selected from the group listed in c) above and further defined as 4-C12H25xe2x80x94(C6H4)xe2x80x94OH and 4-C9H19xe2x80x94(C6H4)xe2x80x94OH, and 2-C3H5xe2x80x94(C6H4)xe2x80x94OH. The present invention comprises ingredients a), b), c), and d). Those knowledgeable and skilled in the art will recognize that other epoxy-functional silicones bearing various other organofunctional groups such as polyethers, hydroxyesters, and the like, may be substituted for the epoxysilicone ingredients a) listed above.
UV curable siloxane fluids provided by the instant invention are more specifically dialkylepoxysiloxy- or trialkylsiloxy chain-stopped polydialkyl-alkylepoxysiloxane copolymers diluted with a reactive vinyl ether monomer plus an alkylphenol. The reactive vinyl ether monomer is independently polymerizable and crosslinkable by virtue of the presence of vinyl ether groups in the monomer, while the alkylphenol will cure into the crosslinked epoxysilicone network. Thus, curing of this combination system as provided by the present invention results in interpenetrating polymerized networks that may or may not be crosslinked to each other.
The epoxy functionality is obtained when certain of the hydrogen atoms on the polysiloxane chain of a polydialkyl-alkylhydrogen siloxane copolymer are reacted with unsaturated epoxide molecules via hydrosilation addition as taught in U.S. Pat. No. 5,258,480.
The radiant energy curable epoxyfunctional silicone fluid can comprise an epoxy-functional dialkyl-alkylsiloxy- or trialkylsiloxy-chainstopped polydialkyl alkylepoxy siloxane copolymer fluid that is the product of sequential hydrosilation reactions involving a polydialkylsiloxane that includes unsaturated groups with a separate polydialkyl-alkylhydrogen siloxane, followed by reaction of an unsaturated epoxy monomer wherein the resulting epoxy-silicone fluid product is subsequently diluted with a vinyl ether plus alkylphenol.
The alkyl groups of the pre-crosslinked polydialkyl-alkylepoxy siloxane are preferably methyl groups. The unsaturated polydialkylsiloxane is preferably a vinyl-dimethylsiloxy chain stopped linear PDMS. The unsaturated epoxy monomer used to make the epoxy functional silicone is preferably an olefinic cyclo-aliphatic epoxy compound such as 4-vinylcyclohexenemonoxide (VCHO), vinylnorbornenemonoxide, limoneneoxide, or dicyclopentadiene monoxide.
Hydrosilation reactions are used for pre-crosslinking and subsequent functionalization of silylhydride containing PDMS. These reactions are catalyzed by low levels of Group VIII noble metal complex compounds. Such complexes are silicone-miscible compounds of ruthenium, rhodium, palladium, platinum, osmium, and iridium. Certain rhodium and platinum complex compounds are particularly preferred, as taught by Eckberg et al in U.S. Pat. No. 5,391,676.
The vinyl functional silicone employed in the pre-crosslinking network synthesis may be selected from the group consisting of dimethylvinylsiloxy-chainstopped polydimethylsiloxane, dimethylvinyl-chainstopped dimethyl-methylvinyl siloxane, tetravinyl tetramethylcyclotetrasiloxane, and sym-tetramethyldivinyldisiloxane.
The hydrogen functional siloxane precursor fluid can be selected from the group consisting of dimethylhydrogensiloxy-stopped polydimethylsiloxane, dimethylhydrogen siloxy-stopped polydimethyl-methylhydrogen siloxane, trimethylsiloxy-stopped polydimethyl-methylhydrogen siloxane, tetramethylcyclotetrasiloxane, and sym-tetramethyldisiloxane.
Certain vinyl ether monomers and oligomers are widely available, and, as cationically polymerizable monomers and oligomers, have been found to be useful additives and diluents in compatible photocurable epoxy-based compositions. Such compositions have been found to be curable by means of electron beam radiation as well as by ultraviolet light. The reactive additives consist in part of vinyl ether monomers and oligomers, with those most preferred for the practice of the instant invention being:
CH2xe2x95x90CHOxe2x80x94(CH2)11CH3,
(CH2xe2x95x90CHOxe2x80x94CH2)2xe2x80x94(C6H10),
(CH2xe2x95x90CHOCH2)(HOCH2)(C6H10),
CH2(CH2COOCH2xe2x80x94C6H10xe2x80x94CH2OCHxe2x95x90CH2)2,
(CH2xe2x95x90CHO(CH2)4OOC)2(C6H4),
CH2xe2x95x90CHO(CHaxe2x88x92bRxe2x80x2bCH2O)cxe2x80x94CHxe2x95x90CH2,
CF3(CF2)dxe2x80x94OCHxe2x95x90CH2,
where a is 2, b is 0 or 1, c and d are integers, and Rxe2x80x2 is an alkyl group selected from CH3, C2H5, C3H7, and C4H9,
and also consist in part of alkylphenol compounds including but not limited to:
4-(C12H25xe2x80x94(C6H4)xe2x80x94OH,
4-(C9H19xe2x80x94(C6H4)xe2x80x94OH,
2-(CH2xe2x95x90CHCH2)xe2x80x94(C6H4)xe2x80x94OH.
The chemical formulas of the compounds in the foregoing lists are written without regard for positional isomerism of substituents. Since the polymerizing and crosslinking of these molecules depends only on the reactive vinyl ether and phenol groups of the vinyl ether monomers and oligomers and alkylphenols, respectively, the relative positional isomerism of these reactive substituents should not affect the chemical properties for which these compounds are used in the instant invention. Therefore these compounds are claimed as the general structures with the expectation that geometric isomers having the same empirical and molecular formula will function similarly to effect the purposes of the invention.
We have discovered that when the vinyl ether+alkylphenol diluted epoxy functional silicone polymers (also referred to as epoxysilicones) are combined with a compatible bis-aryl iodonium catalyst, the resulting mixture can be exposed to ultraviolet light or electron beam radiation to initiate a crosslinking reaction which in turn forms a solid adhesive silicone release coating incorporating the photo-polymerized vinyl ether and alkylphenol possessing a very stable release from common aggressive pressure sensitive adhesives (PSA""s) to which the photocured silicone coating is laminated.
UV light curable or electron beam (EB) curable epoxysilicone compositions of the instant invention may be applied to cellulosic or plastic film substrates including but not limited to supercalenderedkraft (SCK) paper, glassine paper, polyethylene kraft (PK) paper, polyethylene film, polypropylene film, polyester film, and polyvinylchloride (PVC) films. The actinic radiationxe2x80x94initiated crosslinking reaction cures the liquid coating to form a solid, crosslinked non-adherent (or adhesive) surface also known as a release coating on the substrate so coated.
It has been shown that UV and/or EB curable epoxysilicone polymers such as those taught by Eckberg et al in U.S. Pat. No. 4,279,717 and in subsequent patents, are efficiently cured in the presence of certain compatible ""onium type cationic photocatalysts without inhibition by atmospheric oxygen, which is a useful feature of this technology, since practice of such coating processes does not require complex xe2x80x9cinertingxe2x80x9d of cure chambers. Such epoxysilicone compositions are constrained within a narrow range of viscosity and epoxy content dictated by the need for application of defect-free coatings about 0.5 to 2.0 microns thick capable of application on substrates of choice at high speed, and by the necessity that these photocurable epoxysilicone coatings quickly photo-crosslink upon exposure to actinic radiation, all the while retaining good adhesion to the substrate.
Three roll offset gravure or multi-roll film splitting coating techniques are commonly practiced for high speed coating of silicone compositions and are most suited for application of silicones whose viscosity is in the range of 100 to 3000 cstk viscosity at the temperature of application. Rapid cure requires sufficient amount of reactive oxirane be present in the epoxysilicone to ensure high reactivity of the coating, as well as aid in dissolution of the polar ""onium salt catalyst in the coating. But, if too much oxirane is present in the epoxysilicone, the cured coating will not properly release PSA""s.
The epoxy-functional silicones comprising the coating composition of the instant invention are selected from the group consisting of:
MDxDEyQzTuDRfjM,
MEDxDEyQzTuDRfjME,
MEDxDEyQzTuDRfjM,
and mixtures thereof, where:
M=(CH3)3SiO1/2,
ME=(C6H9O)(CH2CH2)(CH3)2SiO1/2
D=(CH3)SiO2/2
DE=(C6H9O)(CH2CH2)(CH3)SiO2/2
DRf=(CF3CH2CH2)(CH3)SiO2/2
Q=SiO4/2
T=CH3SiO3/2
where j, u, x, y, and z are positive integers and j, z, and u may be zero and where said epoxy-functional silicone has a viscosity of between 20 and 100000 cstk at ambient conditions. The subscripts on the various components of the epoxysilicones may be varied at will within the constraints already listed such that the polymer viscosity is within the defined, coatable range. It should be noted that the viscosity of these undiluted epoxysilicones can exceed that which may be readily applied to substrates using conventional application equipment. If a diluent is used to improve the coating characteristics of the epoxysilicone composition it is important that the selected diluent or blend of diluents be capable of reducing the viscosity of the coating composition while maintaining the crosslink density and photoresponse of the curable coating mixture. An additional consideration regarding choice of diluent is that the curing catalyst (an ""onium salt for such cationically polymerizable compounds) must remain miscible with the coating bath. It is known that certain vinyl ethers and vinyl ether oligomers both reduce viscosity and accelerate the photocure of epoxy-based coating compositions. In addition, the inclusion of a second reactive diluent may further advantageously speed crosslinking and improve catalyst compatibility. Thus, the specific combination of vinyl ether and alkylphenol diluents of the instant invention provide for a novel silicone-based coating system that permits use of high viscosity epoxysilicone or of epoxysilicones that would otherwise be immiscible with polar ""onium photocatalysts but for the addition of the vinyl ether and the alkylphenol. Since the coating composition is a solvent-free composition as defined in the art, the fraction of vinyl ether monomers and oligomers and alkylphenols present in the coating mixture can range from about 1 to 90 percent, more preferably from about 2 to 50 percent, and most preferably from about 5 to 25 percent. Based on a coating composition of 100 parts containing about 5 to 20 parts total reactive diluent mixture and 95 to 80 parts epoxy-functional silicone, 0.2 to 3 parts of cationic-type ""onium salt photocure catalyst are added, more preferably 0.2 to 2 parts and most preferably 0.2 to 1.5 part.
The requirement for rapid efficient photocure militates that photocatalysts and, if desired, photosensitizers, be freely miscible with the photocurable compositions in which they are mixed, forming either clear solutions or stable suspensions or dispersions. In the case of epoxy-functional photocurable silicones of the instant invention, ""onium-type cationic salt photocatalysts should be compatible with the epoxysilicone fluid. Iodonium salts of the general formula (R-Ph)2I+Xxe2x88x92 have been designed to address the miscibility issue posed by use of ionic polar substances in nonpolar silicone polymers, where R is typically a mixture of alkyl fragments derived from linear alkylate grade dodecylbenzene; such R is generically termed xe2x80x98dodecylxe2x80x99 although the alkyl groups vary in chain length. As a consequence, the (R-Ph)2I+ salts are mixtures rather than pure compounds and therefore exhibit freezing point depression relative to a pure bis-alkylphenyl iodonium salt and are amorphous, non-crystalline semi-fluids that are more compatible with nonpolar media especially epoxysilicones. Where X=SbF6xe2x88x92 or B(C6F5)4xe2x88x92, the iodonium species are most compatible with epoxysilicone polymers and are most efficient at promoting rapid photocrosslinking reaction; where X=PF6xe2x88x92, Clxe2x88x92 or BF4xe2x88x92 or other similarly small anions whose charge is localized, analogous iodonium salts are poorly compatible with epoxysilicone polymers useful for silicone release coatings. It should be noted that the iodonium salts where the anion is hexafluoroantimonate or tetrakis(perfluorophenyl)borate, while very effective for photocure of epoxysilicone release coatings, are much more expensive than iodonium salts whose anion is hexafluorophosphate or tetrafluoroborate. It is therefore evident that if inexpensive iodonium salts can be made useful for photocure of epoxysilicone coatings in which they are normally immiscible, it would be advantageous for processing of photocurable release coatings.
The UV curable epoxy-functional silicone based compositions of the instant invention can be applied to cellulosic and other substrates including paper, metal, foil, plastic, films, PK paper, SCK paper, and other common liner materials. A UV light or electron beam initiated reaction will cure the epoxysilicone compositions of the present invention to form a non-adherent, adhesive surface on the coated substrate.
Ultraviolet light curable silicone release coating compositions of the instant invention are obtained by combining an iodonium salt effective for catalysis of a UV light initiated reaction of a cationically polymerizable material with a dialkylepoxysiloxy- or trialkylsiloxy-stopped epoxysilicone fluid having a viscosity of about 20 to 100000 cstk at 25xc2x0 C. with a vinyl ether monomer plus an alkylphenol compound.
The preferred UV light initiator or photocatalyst utilized by the present invention is a diaryl iodonium salt derived from xe2x80x98linear alkylatexe2x80x99 dodecylbenzene. Such salts have the following general formula:
[(CxH2x+1)Ph]2I+Yxe2x88x92
where x is an integer varying from about 6 to about 18, Y=SbF6, AsF6, PF6, BF4, or B(C6F5)4xe2x88x92, and Ph stands for a phenyl group. xe2x80x98Linear alkylatexe2x80x99 dodecylbenzene is a commercial grade of alkylbenzenes prepared by Friedel Craft alkylation of benzene with a mixed alpha-olefin distillation cut. Consequently, the alkylate contains both straight and branched chain alkyl benzenes of a wide range of molecular weight and isomer mix. Such a mixture is useful, however, to promote compatibility of the iodonium salt derived therefrom with nonpolar epoxysilicones.
The UV curable silicone coating compositions of the present invention utilize epoxy-functional silicone fluids that can be prepared via different routes. Olefin epoxide compounds that include unsaturation and oxirane functionality react with silyl-hydride functional polysiloxanes via hydrosilation to produce organofunctional siloxanes bearing pendant epoxy groups. 4-vinylcyclohexeneoxide (VCHO) is especially useful for synthesis of UV curable epoxysilicones in this fashion. The analogous hydrosilation reaction between vinyl siloxane groups and silylhydride groups is a well-known means of crosslinking silicone coatings and elastomers. This latter reaction is used to partially crosslink silylhydride functional silicones and vinyl-functional silicones creating a lightly crosslinked loose network, which, provided an excess of silylhydride is present at the onset of the reaction, creates a siloxane network with residual SiH groups that can undergo subsequent addition to unsaturated epoxy monomers such as VCHO to produce epoxysilicones which are partially networked prior to final photocure.
Such epoxysilicones can be prepared from other unsaturated oxiranes including allylglycidyl ether, vinylnorbornene oxide, and dicyclopentadiene monoxide. While cyclohexyl epoxy functional silicones are particularly useful, other olefin epoxies may be used to create epoxysilicones without altering the properties of the cured silicone release coating. The scope of this invention is not limited to the epoxy silicone species used in the examples to follow.
The photocurable epoxysilicone based coating compositions comprising the instant invention are illustrated by numerous example which follow. The instant invention is not limited by the particular examples described. Those skilled in the art will be able to provide other epoxy functional silicones, vinyl ether monomers or oligomers, and other alkylphenol diluents upon consideration of the examples. All US patents referenced in this application are hereby and herewith incorporated by reference.

Cost-effective performance enhancement of UV cured epoxysilicone release agents


A method for compressing an input sequence of data portions is disclosed. The input sequence is compressed using a Lempel-Ziv technique to generate an output codestream. The codestream includes an ordered sequence of codewords corresponding to and separate from a stream of at least one sequence of non-matchable portions in the input sequence. Each codeword includes three data items denoting a length of a non-matchable sequence receding a matchable first sequence, the offset associated therewith and the length of the matchable first sequence. The codewords are used to reference sequences of data portions which previously appeared when decompressing the output codestream to allow the input sequence to be rebuilt. A program storage device and a compressing system for providing the above method are also disclosed.

This invention relates to data compression, and more particularly, to a system and a method for compressing a data sequence using a variant of a Lempel-Ziv technique.
Data compression techniques are used to reduce the amount of data to be stored or transmitted for reducing the storage capacity and transmission time respectively. In either case it is necessary to provide a corresponding decompression technique to enable the original data to be reconstructed.
Many data compression and decompression techniques are known, with the Lempel-Ziv (LZ) technique and its variants proving to be very popular. U.S. Pat. No. 4,558,302, Welch, entitled xe2x80x9cHigh Speed Data Compression and Decompression Apparatus and Method;xe2x80x9d U.S. Pat. No. 4,701,745, Waterworth, entitled xe2x80x9cData Compression System;xe2x80x9d and U.S. Pat. No. 4,814,746, Miller et al., entitled xe2x80x9cData Compression Methodxe2x80x9d are patents that disclose some of these LZ techniques. One of the LZ variants is known as the LZ Opperhumer (LZO) technique. FIG. 1 shows an output codestream obtained by compressing an input character sequence using the LZO technique. The output codestream includes codewords interspersed with non-matchable sequences of characters from the input character sequence. The codewords reference sequences of characters which have previously appeared when decompressing the output codestream to allow the original input character sequence to be rebuilt from the codestream.
There is room for improvement in the LZO technique. Because the codewords are interspersed among the non-matchable character sequences, the codewords need to be byte-aligned. If the codewords are of a variable length, delimiters are also required. The need for byte-alignment of the codewords and for the delimiters results in extraneous bits being included in the LZO output codestream. If the codewords are of a fixed length, the delimiters are not necessary. However, such fixed-length codewords can only represent length of character sequences of up to a value representable by data items in the codewords.
According to an aspect of the present invention, there is provided a method for compressing an input sequence of data portions. The input sequence is sequentially traversed, portion by portion, to determine if a first sequence of portions starting with each portion is matchable with a second sequence of previously traversed portions. If a first sequence is matchable with a second sequence, a length of the first sequence and an offset between the first sequence and the matching second sequence are noted. A stream of at least one non-matchable sequence of data portions in the input sequence is recorded in sequential order. An ordered sequence of codewords separate from the stream is generated. Each codeword includes three data items denoting a length of a non-matchable sequence preceding a matchable first sequence, the offset associated therewith and the length of the matchable first sequence.
According to another aspect of the present invention, there is provided a compressing system having means for compressing an input sequence of data portions as described above.
According to another aspect of the present invention, there is provided a program storage device readable by a computing device, tangibly embodying a program of instructions, executable by the computing device to perform the above method for compressing an input sequence of data portions.

System, method and computer readable medium for compressing a data sequence


In a distributed feedback semiconductor laser, the active medium has a periodic thickness variation in the light propagation direction so as to generate a periodic gain variation, while maintaining the effective refractive index constant, and has a discrete multi-quantum wire structure.

In optical communications systems and, more particularly, in long-haul communications systems, sources capable of emitting single-frequency signals are of primary interest in order to reduce as much as possible signal distortion due to the different propagation rates of the different frequencies. This condition is essential in the case of high-speed direct source modulation and for use in coherent communications systems.
Semiconductor lasers in which optical feedback is obtained by other mechanisms than multiple reflections between the mirrors delimiting the laser cavity are examples of sources meeting the above requirement. In those lasers a selection of the oscillation free (or modes) is obtained without resorting to external components, so that the laser can be fabricated by integrated-optics circuit technology. Moreover, owing to the absence of the end mirrors, the devices are suitable for integration with other components of an optical communications system. Some examples of such lasers are Distributed Bragg Reflector (DBR) lasers and Distributed-Feedback (DFB) lasers. The latter lasers are of simpler manufacture and hence are presently preferred.
Generally, in DFB lasers, optical feedback is obtained thanks to a periodic spatial variation in the effective refractive index (i.e. the refractive index presented by the whole structure for the guided radiation) in the light propagation direction (longitudinal direction). This variation is caused by a grating extending across the whole cavity on or beneath the laser active layer. This optical feedback mechanism is commonly known as "index coupling" and exploits the fact that each refractive index change is accompanied by a weak reflection in the guided radiation. By a suitable choice of the grating period, back reflection will be obtained, and the grating acts as a wavelength-selective mirror, which reflects only the wavelengths closer to that which meets the Bragg condition ##EQU1## where .LAMBDA.=grating period
.lambda.B Bragg wavelength PA1 m=grating order PA1 n.sub.v =mode refractive index
In practice, .lambda..sub.B is chosen so as to be coincident with the emission wavelength of the laser active layer.
Yet, index-coupled DFB lasers are not per se monomode sources, and their behavior, in terms of emitted modes, is highly sensitive to reflections on the end facets. More particularly, if those facets are left untreated, the oscillation modes of the laser depend on the relative positions of the facets with respect to the grating spatial phase, which position is entirely casual, since it is impossible to exactly determine at which point a grating will be cut upon manufacturing the individual devices. If the laser facets are covered with antireflecting coatings, the laser will steadily oscillate on two modes symmetrical with respect to Bragg wavelength. In the latter case monomodality can be achieved by causing the rays propagating in the laser to undergo a quarter-wave phase shift in the central grating zone. This phase shift is obtained by eliminating a groove of the grating in such a zone, which operation is rather complicated from the technological standpoint. The operations necessary to manufacture a grating presenting the phase shift and to apply the antireflecting coatings cause such a cost increase that generally, in the industrial production of such lasers, it is preferred to keep which are monomode by fabrication and to discard the others. Notwithstanding the elimination of a considerable proportion of the production, this approach is still advantageous from the economic standpoint.
The problems of high costs or wastes can be solved by manufacturing a DFB laser where a longitudinal periodic gain variation (gain coupling) occurs instead of a periodic refractive-index variation. It has been theoretically shown (H. Kolgenick, C. V. Shank: "Coupled Wave Theory of Distributed Feedback Lasers", Journal of Applied Physics, Vol. 43, No. 5, May 1972) that a DFB laser is intrinsically a monomode structure and is relatively insensitive to facet reflections, so that no expensive machining such is required for phase-shift introduction in the grating and application of antireflecting coatings is necessary.
An example of gain-coupled DFB laser is described by Y. Luo et al. in the paper entitled "Gain Coupled DFB Semiconductor Laser Having Corrugated Active Layer" presented at the International Conference on Solid Slate Devices and Materials, Tokyo, August 1988, paper 20DPB-2, and issued at pages 328-330 of the proceedings of such a Conference. That paper describes a GaAs/GaAlAs laser, comprising, between conventional confinement layers of GaAlAs (lower and upper claddings), a corrugated layer or grating (pattern-providing layer), this too made of GaAlAs, but with such relative proportions of the constituent elements as to give a refractive index which is high if compared to the lower and upper claddings and is close to that of the active layer. The grating is followed by a further corrugated layer, always made of GaAlAs ("buffer layer"), who index is low but slightly higher than that of the lower and upper claddings. The active layer of undoped GaAs is deposited on the buffer layer in such as to obtain a planar structure. In this way a periodic thickness variation is obtained which causes a periodic gain variation. The refractive indices of the various layers and the heights of the teeth of the pattern-providing layer and the active layer are chosen so that the effective refractive index remains constant in longitudinal direction, so as to obtain a laser with pure gain-coupling.
This known structure presents a number of disadvantages due to the presence of a massive active layer, which does not allow attainment of high values not only of the absolute gain, but also of the differential gain (dg/dN, where g=absolute gain, N=number of the injected carriers). As is known, the higher the differential gain, the better the spectral line-width characteristics of the laser and more generally the dynamic properties of the device (frequency behavior, frequency modulation, etc.).

Gain-coupled distributed-feedback semiconductor laser

CSELT-Centro Studi e Laboratori Telecommunicazioni S.p.A.


The present technology relates to an information processing apparatus, an information processing method, and a recording medium that can improve user's operability on a video image. The information processing apparatus includes: a coordinate system setting unit configured to change an input coordinate system on the basis of a user operation; and a video image control unit configured to control a content in a video image on the basis of a first input coordinate system, and control a display position of the video image on the basis of a second input coordinate system. The present technology can be applied to, for example, a system for displaying a video image on a wall or the like of a room by using a drive-type display device capable of moving a display position of the video image.

Conventionally, it has been proposed to set an input coordinate system on the basis of an orientation of a finger of a user's hand in a case where the user's hand is used to remotely control a video image projected on a wall or the like (see, for example, Patent Document 1).

Information processing apparatus, information processing method, and recording medium


A motor controller including an inverter including plural switching elements that are subjected to PWM control to generate sine waves of plural phases, a motor including a stator coil supplied with the sine waves thus generated so that rotational magnetic field is generated in the stator coil, and a rotor that is rotationally driven by the action of the rotational magnetic field generated by the stator coil, a storage unit for detecting the sine waves of the respective phases generated in the inverter and storing a correction amount for each phase that is calculated on the basis of the detection result so that the sine waves of the respective phases are coincident with one another and a correcting unit for correcting a PWM signal for carrying out the PWM control on the switching elements on the basis of the correction amount thus calculated.

JP-A-2002-10685 (patent document 1) discloses a related art time compensation control for a motor driven by an inverter. The motor control device of this publication provides a compensation amount for a dead time occurring due to PWM control to an PWM signal for driving an inverter. According to this motor control device, a dead time compensation gain is calculated in accordance with a torque amount calculated on the basis of a torque current instruction value, and the compensation gain thus calculated is multiplied by the compensation amount described above to correct the PWM signal. Accordingly, it is possible to smoothen the PWM signal to be transmitted to the inverter, so that it is possible to suppress the current variation of the motor and suppress the torque variation of the motor.
In addition to the above patent document 1, JP-A-2000-85610 (patent document 2) discloses another related art in which a steering device is equipped with a transmission ratio varying mechanism for varying the transmission ratio between a steering angle of a steering wheel and a turning angle of a steered wheel, and the transmission ratio varying mechanism is applied to a motor.
If some dispersion exists in electrical characteristic values of switching elements provided to the inverter, even when a dead time compensation gain is settled and the compensation amount of the dead time is multiplied by the gain to correct the PWM signal, the wave height and waveform of a sine wave of each phase generated by the inverter are not coincident with those of a reference sine wave, surge occurs in torque current and torque variation occurs.
Furthermore, when the motor disclosed in the patent document 2 is driven by using the above motor controller, torque variation occurs in the motor for the above reason, and this torque variation is transmitted to the steering wheel, so that a driver may have an uncomfortable feeling. The same symptom may occur in an electrical power steering in which an auxiliary mechanism for assisting the steering force of a steering wheel is applied to a motor.


The present invention relates to vibration-insensitive point-diffraction interferometry. For the purpose of obtaining high immunity to vibration, a single-mode optical fiber is used to generate the reference wave, by means of point diffraction, directly from a measurement wave reflected from test objects. The capability of vibration desensitization is further strengthened by adding a spatial phase-shift device that enables four interferograms of different amounts of phase shift to be obtained simultaneously with no time delay between interferograms. The present invention may be effectively used in the design of measuring systems for in-line applications where measurements need to be performed in the presence of significant levels of vibration.

1. Field of the Invention
The present invention relates to interferometry. More precisely, the present invention relates to methods and apparatus for a vibration-insensitive point-diffraction interferometer. The methods and apparatus of the present invention may be implemented in measuring systems that measure various parameters of test objects by effectively removing the effect of vibration.
2. Description of the Related Art
Interferometry is a well-established method of measuring various parameters of test objects. Interferometry requires generating two waves; one is generally named the reference wave and the other the measurement wave. The reference wave is generally formed by either a plane wave using the beam of light reflected from a flat surface or a spherical wave using the beam of light generated by means of point diffraction using a pinhole or optical fiber. The measurement wave is generated by either transmitting light through test objects or having light reflected from test objects.
A practical problem encountered in performing interferometry is the presence of vibration, which causes unwanted fluctuation in interference fringes obtained between the reference and measurement waves. The vibration effect is generally considered the main cause of deteriorating measurement accuracy. In order to cope with the vibration problem, several vibration-desensitization methods have been proposed as results of previous work. A method is adopting an active means of monitoring the fluctuation of interference fringes due to vibration using a sensor with subsequent fast moving the reference surface, thus stabilizing the interference fringe (see T. Yoshino et al., Opt. Lett., 23, p. 1576). Another method is using a spatial phase-shift method to capture interference fringes in a very short period time, minimizing vibration fluctuation (see R. A. Smythe et al., Opt. Eng., 23, p. 361). Another method is using a diffraction grating in combination with a pinhole to obtain three spatially phase-shifted interference fringes at the same time (see Osuk Y. Kwon et al., Opt. Lett., 12, p. 855). Another method is using a wave-splitting element that splits the interference wavefront into a plurality of sub-waves with different phase shifts (see U.S. Pat. No. 6,304,330).

Korea Advanced Institute of Science and Technology (KAIST)


Disclosed herein is an improved impact wrench structure, particularly an impact wrench for tightening and loosening fasteners for vehicle tires, it has a reversible motor as a power source to drive a drive wheel at a high speed so that flyweight sides of two hammers provided inside the drive wheel bound outwards by a centrifugal force.. The knocking sides of the two hammers drop downwards, impacting and engaging with reception blocks of the transmission shaft and transmit output power to the transmission shaft. Such actions are repeated to perform the expected function of the novel impact wrench for tightening or loosening fastening components. The structure of the novel impact wrench of the present invention is more simple in construction, more practical in application, convenient in production and much saving cost compared to a conventional one.

1. Field of the Invention
The present invention relates to an improved impact wrench structure, and more particularly to a novel internal structure for an impact wrench having two counterpositioned hammers fixed to a drive wheel and an auxiliary wheel. A spring is engaged to the flyweight side of the brake hammer for restricting the action of the brake hammer. When rotation of the drive wheel rotated by a driving motor reaches to a certain speed, the flyweight side of the brake hammer bounds outwards due to a centrifugal force produced by rotation of the brake hammer itself At this moment the knocking side of the brake hammer drops downward, impacting a reception block of the transmission shaft and engages with it and transmits power to the transmission shaft. The design of the two hammers and incorporated with spring of the present invention contributes to make the impact wrench more practical in application and convenient in assembling and production compared to a conventional one.
2. Description of the Prior Art
The impact wrench available in the market are quite similar in their shapes and functions, but each has its own feature so far as the internal structure is concerned. One of the cases is an utility model under the R.O.C. patent "Spare Tire Installation and Removal Tool" (application Ser. No. 75,207,418), published in R.O.C. Patent Gazette dated Jan. 1, 1987. The internal structure of this utility model is very complicated, it has dozens of components, some of which are intricate in shape, thus causing much inconvenience to the assembling and production.
Another prior art is the utility model "Multipurpose Screw Tightening and Loosening Tool (application Ser. No. 7,821,007) published by the R.O.C. patent Gazette on Mar. 1, 1990. As an improvement of the above-mentioned utility model its structure remains substantially unchanged, the only difference lies on the clutch. The former has a trigger together with a Y-shaped weight board to separate a movable pin from a driving brake element which consequently engaging with a driven brake for transmitting power, while the latter, on the other hand, has a "rapid throwing plate" incorporated with a brake hammer so that when a rotating body reaches a certain rotating speed, "the rapid throwing plate" is expanded outwards by a centrifugal force to separate the movable pin from the brake hammer for transmitting power by engaging the brake hammer with the protruding tooth at the periphery of the brake element. The former is operating mechanically, while the latter makes use of a centrifugal force. Both of them have their own features, but at the same time a weak point in common: they consist of numerous parts and components so that their assembly is time and labor consuming resulting in a high production cost. Moreover, the shapes of some of the components are so complicated that they are difficult to assemble and produce, leading to the obvious shortcoming in terms of the costs and the time spent on assembling.
Furthermore, the impact wrench of the prior art is driven by a motor directly, which requires a higher torque and thus a motor of higher power rating is required, which in turn adds an extra weight to the impact wrench, causing increase of production cost and inconvenience to users as well.


A semiconductor memory device and a method of operating the same are disclosed. The semiconductor memory device includes a memory cell array configured to include memory cells, a peripheral circuit configured to perform an erase operation and a soft program operation and a control circuit configured to control the peripheral circuit so that the memory cells are programmed though a hot carrier injection HCI method when the soft program operation is performed.

1. Technical Field
The present invention generally relates to a semiconductor memory device and method of operating the same, more particularly relates to a semiconductor memory device for performing a soft program operation after an erase operation is performed and method of operating the same.
2. Related Art
A semiconductor memory device is a memory device for enabling to store and read data. The semiconductor memory device is divided into a random access memory RAM and a read only memory ROM. Data stored in the RAM becomes lost if power is not supplied. This memory is referred to as a volatile memory. However, data stored in ROM is not lost though the power is not supplied. This memory is referred to as non-volatile memory.
A memory cell is programmed though an FN tunneling method when a program operation of the semiconductor memory device is performed. In case that high voltage is applied to a control gate of the memory cell in the program operation, electrons are charged in a floating gate of the memory cell. In a read operation of the semiconductor memory device, threshold voltage of the memory cell varied according to amount of the electrons charged in the floating gate is detected, and read data is determined according to level of the detected threshold voltage.
An erase operation of the semiconductor memory cell may be performed in the unit of selected block. For example, the erase operation may be performed by applying a ground voltage, e.g. 0V to every word line included in the selected block and providing an erase voltage, e.g. 20V to a well of the block.
Since threshold voltage distribution of memory cells of which an erase operation is finished is generally wide, a time taken for the program operation performed after the erase operation may increase. For example, in case that a memory cell having lowest threshold voltage and a memory cell having greatest threshold voltage of the erased memory cells are programmed simultaneously, velocity difference of the program operation between two memory cells occurs.
To improve the velocity difference, a soft program operation is performed after the erase operation is finished.
FIG. 1 is a view illustrating circuit diagram of a string in a memory cell array of a semiconductor memory device.
FIG. 2 is a view illustrating a graph showing threshold voltage (i.e., Vt) distribution according to a conventional soft program operation (i.e., No).
In FIG. 1 and FIG. 2, in the soft program operation, a ground voltage is applied to bit lines BL, and a supply voltage is provided to a drain select line DSL and a ground voltage is applied to a source select line SSL under the condition that a source line SL may be connected to the supply voltage. Every memory cell MC0 to MCn are soft-programmed simultaneously by applying simultaneously a soft program voltage to word lines WL<0:n> so as to have one or more memory cells having threshold voltages higher than a soft program verification voltage SEV. That is, the soft program operation is performed by using a program operation through the FN tunneling method similar to common program operation method (i.e., FN PGM). However, in case that every memory cell is simultaneously programmed through FN tunneling method, threshold voltage of every memory cell increases, and so effect of reducing width of the threshold voltage distribution is inadequate. In other words, the threshold voltage distribution B of the memory cells for which the soft program operation is finished increases comparing to threshold voltage distribution A (where the target threshold voltage is indicated by HEV) of the memory cells before the soft program operation is not performed, but the width of the threshold voltage distribution does not reduce.

Semiconductor memory device and method of operating the same


A lighter than air balloon constructed from a flexible film material which has coated one or more of its interior or exterior surfaces thereon a barrier material which is not a pure metal and which has an oxygen transmission rate of less than 0.5 cm.sup.3 /100 in.sup.2 /24 hr. at 75.degree. F., 65% relative humidity, said balloon being able to float when inflated with a lighter than air gas and a process for producing the balloon is provided.

1. Field of the Invention
The present invention relates to lighter than air balloons. More specifically, the balloons are constructed from a polymeric film material which has coated thereon a barrier material having an oxygen transmission rate of less than 0.5 cm.sup.3 /100 in.sup.2 /24 hr. at 75.degree. F., 65% relative humidity. The film material may also be used for other applications such as food and beverage packaging.
2. Technology Description
Conventional lighter than air balloons are typically produced by filling an elastomeric material with a helium containing gas to enable the balloon to "float". Such balloons may be used for novelty purposes and are commonly sold at fairs, circuses, restaurants, gift shops, and the like. While these balloons are still in great use, they are relatively limited in their appearance and by their limited lifetime as a result of helium diffusing through the elastomeric material. Elastomeric balloons have also been used for technical applications, e.g., carrying weather instruments to the upper atmosphere.
Within the past 20 years, a new form of balloon made from polymeric film materials has been produced which has been extremely successful as a premium item. Such balloons are typically constructed of Nylon-6 and have coated thereon a metal layer to reduce the rate of helium diffusion and give the balloon a more attractive appearance. As novelties, these balloons are generally sold for special holidays such as birthdays, graduations, anniversaries, Valentine's Day, and the like at card shops, florists, and other shops. Metallized nylon-6 and metallized polyester films are used for technical applications as well. The key criteria for such balloons is that they be constructed of a material which will float when filled with helium and also be relatively gas impermeable to enable to helium to remain in the interior of the nylon film for extended periods of time.
Examples of such premium novelty balloons are described in the literature. U.S. Pat. Nos. 4,077,588 and 4,290,763 disclose a laminate of a nonelastomeric continuous polymer film having coated thereon a metal film. U.S. Pat. No. 4,693,695 discloses an ascending and descending balloon made from this laminate material.
U.S. Pat. No. 5,023,118 discloses artificial flowers made from non-elastomeric polymer sheets whose inner surfaces are coated with continuous metallic coatings. Laminates having multiple polymer sheets and/or metallic coatings are also suggested for use.
In the case of metallized nylon balloons, both the metal layer and the nylon substrate provide the barrier to helium penetration. Balloons made from metallized polyester have relied heavily on the metal layer for the barrier until now.
A fundamental desire is to provide a material which has a lower weight to area ratio to allow smaller, flotable balloons as well as move innovative shapes. A secondary desire is to reduce the cost of raw materials when producing such premium novelty balloons. More specifically, it would be desirable to produce premium novelty balloons from polymers that are lighter than nylon on a per unit area basis.
Accordingly, there exists a need in the art for balloons which are made from polymeric substrate film materials, are produced from relatively inexpensive raw materials, and can float for extended periods of time.


A sampling function waveform data generating device for fast generating data on a waveform approximating a sampling function with a simple circuit structure. Data on a waveform of a step function is outputted from a memory 20. A first digital integrating circuit 30 integrates the data on waveform of the step function and outputs data on a waveform of a broken-line function. A second digital integrating circuit 40 integrates the data on the waveform of the broken-line function and outputs data on a waveform approximating a sampling function. The outputted sampling function is a function of a local support that is differentiable once, takes on 1 in sampling position t=0, 0 in all the other sampling positions, 0 in the ranges t less than xe2x88x923 and t greater than +3, and a value other than 0 in the other range, and converges to 0 in sampling positions t=xc2x13.

The present invention relates to a sampling function waveform data generating device for generating waveform data based on a sampling function.
Conventionally, a CD (Compact Disk) player, uses a D/A (digital-to-analog) converter to which an over-sampling technique is applied to obtain a continuous analog audio signal from discrete digital music data. Such a D/A converter generally uses a digital filter to raise a pseudo sampling frequency by interpolating input digital data, and outputs smooth analog voice signals by passing each interpolation value through a low-pass filter after generating a staircase signal waveform with each interpolation value held by the sample holding circuit.
A data interpolating process is performed with a digital filter mentioned above using a sampling function generally referred to as a sinc function. FIG. 7 is an explanatory graph of a sinc function. This sinc function is obtained when a Dirac delta function is inverse-Fourier-transformed, and is defined as sin (xcfx80ft)/(xcfx80ft) where the sampling frequency is f. This sinc function becomes one only at a sample point, where t=0, and zero at all other sample points. In the FIG. 7, sinc function corresponding to the range where t=xc2x13 is showed.
A sinc function converges to 0 as a variable t goes to +∞ or xe2x88x92∞, and if the correct interpolated value is obtained, all the digital data values must be considered. However, actually, the tap coefficients of a digital filter are set up in a limited range of digital data under consideration from the convenience of the circuit scale, whereby the interpolated value contains a truncation error. This truncation error can be decreased by setting the number of tap coefficients for the digital filter at higher degree, in which there is a problem that the circuit scale is increased, with a tradeoff relation between decreasing the truncation error and reducing the circuit scale. Moreover, when such an oversampling operation is performed in DSP, etc., a value of the above mentioned sampling function (sinc function) has to be kept computing at a high speed, thereby limiting the process performance.
Such a problem is caused by employing the sinc function as a sampling function correctly. Considering that a truncation error or a quantizing noise may occur even when the sinc function is used, there is less need of generating the sinc function at high precision. Accordingly, if the function values approximating the sinc function can be generated fast in a predetermined range with a simple circuit structure, the data interpolation process is enabled by using the function values in the same manner as when using the sinc function.
The present invention has been developed based on the above mentioned problems, the object of the present invention is to provide a sampling function waveform data generating device for fast generating data on a waveform approximating a sampling function with a simple circuit structure.
A sampling function waveform data generating device of the present invention comprises data output unit for sequentially outputting digital waveform data of a predetermined step function, and digital integrating unit for digitally integrating the waveform data output from the data output unit to output a sampling function of a local support that takes 1 in sampling position t=0, 0 in all the other sampling positions, 0 in the range t less than xe2x88x92n and t greater than +n where n is a positive integer greater than 1, and a value other than 0 in the other range, and converges to 0 in sampling positions t=+n.
The sinc function takes 1 only in sampling position t=0, and 0 in all the other sampling positions, and converges to 0 as t goes to +∞ or xe2x88x92∞m, as shown in FIG. 7. When this sinc function is applied to the practical circuit, a limited range of sampling position is employed so that a truncation error is overlooked in the current situation. Thus, in this invention, the sinc function itself is not output, but a waveform approximating the sinc function is output. Namely, the sinc function is substituted by a sampling function of a local support that is differentiable finite times, and takes 1 in sampling position t=0, 0 in all the other sampling positions, 0 in the range t less than xe2x88x92n and t greater than +n where n is a positive integer greater than 1, and a value other than 0 in the other range, and converges to 0 in sampling positions t=+n. In order to obtain the waveform that is differentiable finite times, the integration may be made. For example, a broken-line function with a waveform as shown in FIG. 5 can be obtained by integrating a step function with a waveform as shown in FIG. 2. Further, a waveform approximating the sampling function as shown in FIG. 6 can be obtained by integrating the broken-line function with the waveform as shown in FIG. 5. Thus, in this invention, digital waveform data of the step function as shown in FIG. 2 is output sequentially, employing the data output unit, and then integrated plural times by the digital integrating unit, whereby the sampling function as shown in FIG. 6 is generated through the digital processing. The sampling function as shown in FIG. 6 converges to 0 in sampling positions t=xc2x13, and can be employed to make the interpolation, whereby three sampling values before and after the interpolated position may be only considered to reduce the amount of operations largely. Also, since the interpolation is truncated at the sampling positions where the function converges to 0, but not halfway of the sampling positions to be operated such as the sinc function, the influence due to truncation error can be eliminated. Further, since the range of sampling position to be operated can be narrowed, the less number of data is necessary to be held so that the circuit scale can be reduced.
It is desirable that the digital integrating unit outputs a sampling function of a local support that takes 1 in sampling position t=0, 0 in sampling positions t=xc2x11, t=xc2x12, t less than xe2x88x923 and t greater than +3, and a value other than 0 in the other range, and converges to 0 in sampling positions t=xc2x13. This is a case where the value of n is limited to 3, and it is possible to output a sampling function that converges to 0 in sampling positions t=xc2x13, as shown in FIG. 6.
Also, it is desirable that the digital integrating unit outputs a sampling function of a local support that takes 1 in sampling position t=0, 0 in sampling positions t=xc2x11, t less than xe2x88x922 and t greater than +2, and a value other than 0 in the other range, and converges to 0 in sampling positions t=xc2x12. This is a case where the value of n is limited to 2, and it is possible to output a sampling function that converges to 0 in sampling positions t=xc2x12.
Furthermore, the data output unit preferably comprises a memory for holding the values of the step function, and data reading unit for reading cyclically the values held in the memory in predetermined order. Since the waveform data of the sampling function having the value changing continuously can be generated only by holding the values of the step function, the circuit scale can be more reduced.
Furthermore, it is preferable that the sampling function is differentiable finite times. The sampling function that is differentiable finite times can be generated by integrating the waveform data of the step function a predetermined number of times, resulting in the simplified processing.

Sampling function waveform data generating device


A multi-stage inflator including a housing at least in part defining first and second combustion chambers each containing a quantity of gas generant reactable to form respective product gases. The inflator includes first and second initiators each operatively associated with a respective one of the combustion chambers in reaction initiating communication with at least a portion of the quantity of the gas generant therein contained such that upon actuation the gas generant ignites to form product gas. The second combustion chamber has an exit opening to allow product gas to exit from the second combustion chamber and into the first combustion chamber. The housing includes at least one discharge opening to permit gas to exit the housing and an end wall and wherein both the first and the second initiators are connected.

This invention relates generally to inflators for use in inflating inflatable restraint airbag cushions, such as used to provide impact protection to occupants of motor vehicles. More particularly, the invention relates to inflator devices having multiple or plural stages or levels of inflation gas output and as such may be used to provide an inflation gas output which is adaptive to factors such as one or more crash and occupant conditions.
It is well known to protect a vehicle occupant by means of safety restraint systems which self-actuate from an undeployed to a deployed state without the need for intervention by the operator, i.e., "passive restraint systems." Such systems commonly contain or include an inflatable vehicle occupant restraint or element, such as in the form of a cushion or bag, commonly referred to as an "airbag cushion." In practice, such airbag cushions are typically designed to inflate or expand with gas when the vehicle encounters a sudden deceleration, such as in the event of a collision. Such airbag cushions may desirably deploy into one or more locations within the vehicle between the occupant and certain parts of the vehicle interior, such as the doors, steering wheel, instrument panel or the like, to prevent or avoid the occupant from forcibly striking such parts of the vehicle interior. For example, typical or customary vehicular airbag cushion installation locations have included in the steering wheel, in the dashboard on the passenger side of a car, along the roof line of a vehicle such as above a vehicle door, and in the vehicle seat such as in the case of a seat-mounted airbag cushion. Other airbag cushions such as in the form of knee bolsters and overhead airbags also operate to protect other or particular various parts of the body from collision.
In addition to an airbag cushion, inflatable passive restraint system installations also typically include a gas generator, also commonly referred to as an "inflator." Upon actuation, such an inflator device desirably serves to provide an inflation fluid, typically in the form of a gas, used to inflate an associated airbag cushion. Various types or forms of inflator devices have been disclosed in the art for use in inflating an inflatable restraint system airbag cushion. One particularly common type or form of inflator device used in inflatable passive restraint systems is commonly referred to as a pyrotechnic inflator. In such inflator devices, gas used in the inflation of an associated inflatable element is derived from the combustion of a pyrotechnic gas generating material.
In view of possibly varying operating conditions and, in turn, possibly varying desired performance characteristics, there is a need and a desire to provide what has been termed an "adaptive" inflator device and a corresponding inflatable restraint system. With an adaptive inflator device, output parameters such as one or more of the quantity, supply, and rate of supply of inflation gas, for example, can be selectively and appropriately varied dependent on selected operating conditions such as one or more of ambient temperature, occupant presence, seat belt usage and rate of deceleration of the motor vehicle, for example.
Pyrotechnic inflators typically may have one or more chambers containing gas generant. Adaptive pyrotechnic inflators having gas generant material in two chambers, for which reaction is each independently initiated by a specified initiator, have been referred to as "dual stage" inflators.
In practice, each such gas generant material-containing chamber is oftentimes referred to as a "combustion chamber" as the gas generant material therein contained is burned or otherwise reacted to produce or form gas such as may be used to inflate an associated inflatable restraint airbag cushion. The initiators are typically electrically-actuated. As a result, dual stage tubular passenger inflators are commonly configured with one initiator electrical connection on each of two opposite ends of a tubular-shaped inflator body. Such an inflator construction necessitates an inflatable restraint system airbag module that allows access to both ends of the tubular inflator so that appropriate required electrical connections can be made thereto.
Dual stage inflators may have several contemplated firing scenarios. In a first such scenario, only the gas generant material in a first or primary chamber is actuated whereby a fixed quantity of inflation gas is produced thereby. In a second possible firing scenario, the first or primary chamber is first actuated whereby gas generant material in the first chamber is first reacted to start to produce or form inflation gas and after a predetermined or preselected delay, the gas generant material in a second or secondary chamber is then actuated whereby gas generant material in the second chamber is reacted to also produce or form inflation gas. In a third possible firing scenario, the gas generant material in the first chamber and the gas generant material in the second chamber are actuated simultaneously to produce or form inflation gas from the gas generant material in each of the chambers.
As will be appreciated, through the selection and use of an appropriate such firing scenario, inflator output parameters such as one or more of the quantity, supply, and rate of supply of inflation gas, for example, can be selectively and appropriately varied dependent on selected operating conditions such as one or more of ambient temperature, occupant presence, seat belt usage and rate of deceleration of the motor vehicle, for example.
Multi-stage and adaptive inflator devices find widespread use in modern day vehicle occupant safety restraint systems. Such use leads to a need and desire for improved such inflator devices such as capable of specifically varying selected inflation performance scenarios. Thus, there is a need and demand for such inflator devices and associated methods of operation of increased simplicity and reliability of operation and design. In particular, there is a need and demand for such inflator devices and associated methods of operation that provide or result in specifically desired inflation performance scenarios in a less costly and/or more efficient manner.


A compression technique is used to suppress the idle or silent portion of both stations in a facsimile transmission. Facsimile transmission is a half-duplex protocol resulting in considerable idle time for either the called terminal or the calling terminal. The invention provides a signal level threshold for each station whereby signals above the threshold are allowed to pass through while signal levels below threshold are not, resulting in more efficient network bandwidth utilization.

Facsimiles are well known for exchanging written time-critical information. Early facsimile standards, i.e., CCITT Group 1 (1960) and CCITT Group 2 (1976) established a relatively slow rate of transmitting data between terminals with times of 5 or 6 minutes per page being common. These standards are used rarely today but are still supported for backward compatibility. The current dominant standard is CCITT Group 3 which has boosted image quality and reduced transmission time to as little as 6 seconds per page. Group 1 and Group 2 standards use tonal signal for control and handshaking whereas Group 3 uses binary coded Frequency Shift Keying (FSK) signalling.
Modems are also used extensively for transmitting data over the public switched telephone network between terminals including computers and the like.
Facsimile transmission between terminals is half-duplex, meaning that only one of the two terminals is transmitting at any one time. During a typical facsimile connection, the transmitting (calling) terminal sends a calling (CNG) signal (a 1100 Hz calling tone) and the receiving (called) terminal replies with a called (CED) signal (a 2100 Hz called station identifier) and a digital identification signal (DIS) at 462 Hz. After the handshaking, which consists of a transmit digital command signal (DCS), a training signal and a received confirmation to receive (CFR), the calling facsimile starts transmitting the first page with compression according to CCITT (ITU) T.4. The called facsimile is silent at this time.
Systems such as Magellan Passport allows the carriage of synchronous digital data (voice and non-voice) over a cell-based Magellan Passport network. Magellan and Passport are trademarks of Northern Telecom.
Two techniques for compression or bandwidth saving are used for the data voice component in Passport: Adaptive Differential Pulse Code Modulation (ADPCM) and silence suppression. ADPCM compression is a means of looking at successive data and coding the difference instead of the data itself. Thus the number of bits representing a sample data can go from 8 to 4, 3 or 2 bits per sample. On the other hand, silence suppression uses knowledge of speech properties and dynamics to reduce transmission requirements.

Idle suppression and signal threshold determination therefor


A hydraulic spool valve includes a housing, a valve element disposed within the housing, a first piston coupled to the valve element, and a first biasing member. The housing includes a pair of first ports. The valve element is selectively moveable within the housing between a first closed position and a second open position allowing fluid communication between the first ports. Hydraulic pressure against the first piston causes helical translation of the piston in a first direction, and motion of the valve element in a first direction from the first position toward the second position. The first biasing member is configured to bias the first piston and the valve element toward the first position.

1. Field of the Invention
The present invention relates generally to hydraulic valves. More particularly, the present invention relates to a hydraulic spool valve having an internal helical actuator.
2. Related Art
Spool valve manifolds are used to accomplish opening and closing of ports, such as for directing hydraulic fluid to various hydraulic devices. These types of manifolds are frequently used in aircraft, for example, to selectively direct hydraulic fluid between actuators for ailerons, flaps, rudders and other flight surfaces, as well as actuators for landing gear, thrust reversers, and other hydraulic devices.
Current spool valve manifolds tend to be relatively large and heavy. They are typically long in order to accommodate a number of ports that are sequenced in-line (e.g. neutral, open, & closed positions). This length and size gives them a fairly large volume. These types of valves also tend to be heavy because they are often machined from solid metals, such as titanium. The size, weight and volume of typical hydraulic spool valve manifolds is a concern in the field of aviation and other applications of these types of valves.