A self-sacrifice type metal corrosion inhibitor is prepared by dispersing one or more kinds of metal powder having a greater ionization tendency than that of a metal to be treated and a water-insoluble thermoplastic resin powder in water containing a water-soluble anticorrosion agent, a surface-active agent and a thickener to from a treatment solution. The treatment solution is applied to the surface of the metal to be treated, which is heated to melt the thermoplastic resin powder and form a thermoplastic resin layer fixed to the surface of the metal. It forms a metal corrosion-inhibiting layer fixed to the surface through the thermoplastic resin, which acts as an adhesive layer.

The present invention relates to a self-sacrifice type metal corrosion inhibitor for the corrosion proof treatment of the surface of the metal such as iron or iron alloy and a metal corrosion inhibiting method using said self-sacrifice type metal corrosion inhibitor.
Hitherto, a metal corrosion inhibitor comprising a metal powder having a greater ionization tendency than that of a metal to be treated such as zinc powder or aluminum powder in a case where said metal to be treated is iron or iron alloy, chromium (VI) source such as chromate and the like, pH adjusting agent such as metal oxide, metal hydroxide and the like, reducing organic compound such as low molecular oxohydroxy ether and the like, and water soluble solvent has been provided.
Said traditional metal corrosion inhibitor is adhered to the surface of a metal to be treated and chromium (VI) from said chromium (VI) source may be reduced by said reducing organic compound to chromium (III) to sedimentate on the surface of said metal to be treated by heating and said metal powder is adhered to, and fixed on the surface of said metal to be treated through said chromium (III) layer as an adhesive layer to form a metal corrosion inhibiting layer.
Hitherto, zinc-electro plating, zinc-mechanical plating and zinc-mechanical galvanized, zinc-melting plating and the like have been also used for the metal corrosion inhibiting treatment.
Said traditional metal corrosion inhibitor contains chromium (VI) source and in said zinc-electro plating, zinc-mechanical plating and zinc-mechanical galvanized, zinc-melting plating and the like also chromium (VI) is used to improve the metal corrosion inhibiting property. Nevertheless, said chromium (VI) is poisonous and it becomes difficult to use said chromium (VI) considering environmental contamination. Further said zinc-mechanical plating and zinc-mechanical galvanized has a problem of noise so that the advert of a self-sacrifice type metal corrosion inhibitor has been desired. Said self-sacrifice type metal corrosion inhibitor may contain no poisonous component and cause no public nuisance and no noise while said self-sacrifice type metal corrosion inhibitor has a metal corrosion inhibiting property equal to the traditional metal corrosion inhibitor containing chromium (VI) source.
Accordingly, an object of the present invention is to provide a self-sacrifice type metal corrosion inhibitor causing no public nuisance and no noise.
Another object of the present invention is to provide a self-sacrifice type metal corrosion inhibitor having a metal corrosion inhibiting property equal to the traditional metal corrosion inhibitor containing chromium (VI).
Briefly, said objects of the present invention can be attained by a self-sacrifice type metal corrosion inhibitor comprising;
one or more kind(s) of metal powder having a greater ionization tendency than that of a metal to be treated, water insoluble thermoplastic resin powder, water soluble anticorrosion agent, surface active agent, thickener and water; and
a metal corrosion inhibiting method comprising; preparing a treatment solution by dispersing said metal powder having a greater ionization tendency than that of said metal to be treated and said water insoluble thermoplastic resin powder in water containing said water soluble anticorrosion agent, said surface active agent and said thickener, adhering said treatment solution to the surface of said metal to be treated, heating said metal to be treated to melt said thermoplastic resin powder and form a thermoplastic resin layer fixed on the surface of said metal to be treated, and forming a metal corrosion inhibiting layer on the surface of said metal to be treated by fixing said metal powder on the surface of said metal to be treated through said thermoplastic resin layer as an adhesive layer; and further
a metal corrosion inhibiting method comprising; a treatment solution by dispersing said metal powder having a greater ionization tendency than that of said metal to be treated and said water insoluble thermoplastic resin powder in water containing said water soluble anticorrosion agent, said surface active agent and said thickener, adhering said treatment solution to the surface of said metal to be treated, heating said metal to be treated to melt said thermoplastic resin powder and form a thermoplastic resin layer fixed on the surface of said metal to be treated, and forming a metal corrosion inhibiting layer on the surface of said metal to be treated by fixing said metal powder on the surface of said metal to be treated through said thermoplastic resin layer as an adhesive layer; and further treating with a mixture of polymer and/or oligomer and Na2O:nSiO2 (n=3 or 4) as a self-restoring agent for the self-sacrifice type corrosion inhibiting property of said metal corrosion inhibiting layer wherein said polymer and/or oligomer is(are) one or more polymer or oligomer selected from a group consisting of poly (meth)acrylic acid, copolymer of (meth)acrylic acid and other vinyl monomer which can be copolymerized with (meth)acrylic acid, (meth)acrylic acid oligomer, and oligomer consisting of (meth)acrylic acid and other vinyl monomer which can be copolymerized with (meth)acrylic acid.
In a case where said metal to be treated is iron or iron alloy, zinc powder or aluminum powder or zinc-aluminum alloy powder is preferably used.
In said metal corrosion inhibitor of the present invention, said metal powder and said water insoluble thermoplastic resin powder are stably dispersed in water containing said water soluble anticorrosion agent, said surface active agent and said thickener.
When said treating solution is adhered on the surface of said metal to be treated and heated, said water insoluble thermoplastic resin is melted to adhere the surface of said metal to be treated and a metal corrosion inhibiting layer is formed. In said metal corrosion inhibiting layer, said thermoplastic resin powder maintains powder form since said thermoplastic resin powder is insoluble in water, the resulting thermoplastic resin layer on the surface of said metal to be treated has a porous structure. Accordingly said metal corrosion inhibiting layer consisting of said metal layer which is fixed on the surface of said metal to be treated by said thermoplastic resin layer also has a porous structure, and as a result said metal corrosion inhibiting layer becomes an electroconductive layer having a low electric resistance and a desirable electric resistance on the surface of said metal to be treated is guaranteed.
Further when said treated metal is further treated with a mixture of polymer and/or oligomer and Na2O:nSiO2 (n=3 or 4) as a self-restoring agent for the self-sacrifice type corrosion inhibiting property of said metal corrosion inhibiting layer wherein said polymer and/or oligomer is(are) one or more polymer or oligomer selected from a group consisting of poly (meth)acrylic acid, copolymer of (meth)acrylic acid and other vinyl monomer which can be copolymerized with (meth)acrylic acid, (meth)acrylic acid oligomer, and oligomer consisting of (meth)acrylic acid and other vinyl monomer which can be copolymerized with (meth)acrylic acid, to form an organo silicate compound layer on said metal corrosion inhibiting layer, a self-restoring property equal to or higher than that of zinc-chromate treatment layer is given to said metal corrosion inhibiting layer.
Said treatment solution consisting of only nonpoisonous components contains no poisonous component such as chromium (VI) source and the like.
Metal powder used in the present invention consists of a metal having a greater ionization tendency than that of a metal to be treated and in a case where said metal to be treated is iron or iron alloy, said metal powder may be zinc powder, aluminum powder, zinc-aluminum alloy powder and the like. The purity of said metal powder is preferably higher than 99.0% by weight, more preferably higher than 99.5% by weight and said metal powder has preferably powder form or flake form. In the case of zinc powder having flake form, the thickness is preferably less than 3 xcexcm, more preferably less than 2 xcexcm and the diameter is preferably less than 10 xcexcm, more preferably less than 7 xcexcm, and in the case of aluminum powder having flake form, the thickness is preferably less than 1 xcexcm, more preferably less than 0.5 xcexcm and the diameter is preferably less than 10 xcexcm, more preferably less than 7 xcexcm. The thinner is the better in each case where said metal powder has flake form.
Silver powder or silver flake, gold powder or gold flake, nickel powder or nickel flake, titanium powder or titanium flake, copper powder or copper flake and the like may be used instead of said metal powder or alloy powder or partially added to said metal powder or alloy powder.
Desirably, the surface of said metal powder may be treated with a treatment agent such as higher fatty acid, higher alcohol, wax having a high melting point, paraffine having a high melting point, antioxidant and the like. To treat the surface of said metal powder with said treatment agent, said metal powder may be dipped in a solution of said treatment agent using kerosine, mineral spirit, mineral terpin and the like as a solvent or said solution may be sprayed to said metal powder.
It is preferable to use zinc powder and aluminum powder together comparing the case where zinc powder or aluminum powder is singly used since when the surface of said metal to be treated is treated with zinc powder and aluminum powder together, zinc powder having a smaller ionization tendency and a higher specific gravity than aluminum may be migrated to the lower side of the treatment layer and aluminum may be migrated to the upper side of the treatment layer and as a result, a desirable self-sacrifice type metal corrosion inhibiting property is given to said surface of said treated metal.
Said metal powder may give a low electric resistance to said treatment layer and guarantee the preferable electroconductivity of the surface of said treated metal and said metal powder may be added in said treatment solution commonly in an amount between 1 to 75% by weight, desirably 5 to 40% by weight. In a case where the self-sacrifice type metal corrosion inhibiting property is very important, both zinc powder and aluminum powder are desirably used. In this case, the adding amount of zinc powder is desirably settled to be more than two times as the adding amount of aluminum, and the adding amount of zinc powder may be settled to be 1 to 30% by weight, desirably 5 to 25% by weight, and the adding amount of aluminum powder may be settled to be 1 to 25% by weight, desirably 2 to 15% by weight.
When silver, gold, nickel, titanium or copper is used as a material of said metal powder, the electric resistance of the resulting treatment layer may be much lower and the electroconductivity of said treatment layer may be much higher so that said treatment solution can be used in the electromagnetic wave shield treatment, photocatalyst, and the like besides the metal corrosion inhibiting treatment.
Water insoluble thermoplastic resin is used to adhere said metal powder to the surface of said metal to be treated and to adhere said metal powder together in the present invention. When water-soluble thermoplastic resin is used as an adhesive agent, said thermoplastic resin dissolves in water so that the surface of said metal to be treated may be wholly covered with said thermoplastic resin layer and non-electroconductive film of said thermoplastic resin layer may be formed between said metal powders and the surface of said metal to be treated, which inhibits the electroconductivity of said treatment layer and the self sacrifice type metal corrosion inhibiting property may not be produced sufficiently.
In the present invention, water insoluble thermoplastic resin powder is used not to inhibit the electroconductive ity of said treatment layer. The smaller particle size of said thermoplastic resin powder may result in the smaller using amount of said thermoplastic resin powder and adhesion of said metal powder together and between said metal powder and the surface of said metal to be treated may become more partial, resulting in an excellent electroconductivity and said treatment layer having self-sacrifice type metal corrosion inhibiting property may become finer and stronger.
Said water insoluble thermoplastic resin powder may be such as thermoplastic epoxy resin, polyethylene, polyvinylchloride, nylon resin such as nylon 6, nylon 66, nylon12, nylon 612, nylon 12 copolymer and the like, fluoro carbon resin such as PTFE, PFA, FED, teflon derivative and the like, epoxy-polyester copolymer, polyolefin thermoplastic elastomer such as TPE and the like, polycarbonate resin, polyacetal resin, melamine resin and the like.
Said water insoluble thermoplastic resin has been traditionally used in the powder coating process. The diameter of said thermoplastic resin powder is preferably less than 40 xcexcm, more preferably less than 20 xcexcm. The smaller diameter of said thermoplastic resin powder is better for the present invention. The using amount of said water insoluble thermoplastic resin powder may be 1 to 35% by weight, desirably 1 to 10% by weight.
Said water soluble anticorrosion agent used in the present invention has been traditionally used in cooling water for the radiator, the engine, and the like of the automobile and said water soluble anticorrosion agent is used for anticorrosion treatment of steel, cast iron, copper, copper alloy, solder, zinc, aluminum and the like. Many kinds of water soluble anticorrosion agent passing the anticorrosion ability test (metal corrosion test) JAOS-7014 can be used in the present invention.
Typically said water soluble anticorrosion agent may comprise an amide of lower fatty acid such as diethanol amide of hippuric acid, diethyl amide of hippuric acid, diethanol amide of saccinic acid amide and the like, and nitrite such as dicyclohexylamine nitrite, cyclohexyl amine nitrite, diethanol amine nitrite and the like. The adding amount of said water soluble anticorrosion agent may be commonly 0.1 to 10% by weight, desirably 0.5 to 3% by weight.
In the metal corrosion inhibitor of the present invention, a surface active agent is used to disperse said metal powder and said water insoluble thermoplastic resin powder in water stably.
Said surface active agent may be alkylaryl ether type nonionic surface active agents such as polyoxyethyleneno nylphenyl ether, polyoxyethyleneoctylphenyl ether and the like, alkyl ether type nonionic surface active agents such as polyoxyethylenebutyl ether, polyoxyethyleneoctylether, polyoxyethylenelauryl ether, polyoxyethyleneoleyl ether, polyoxyethylenestearyl ether, alkyl acetate type nonionic surface active agents such as polyoxyethylenelaurate, polyoxyethyleneo leate, polyoxyethylenestearate and the like, and ethylene oxide-propylene oxide block copolymer type nonionic surface active agents such as polypropylene glycol-polyethylene glycol ether and the like.
It is preferable to select a surface active agent containing no aryl group considering environmental hormone contamination. Further, it is preferable to select a surface active agent having H.L.B (Hydrophile-Lipophile Balance) value 7 to 18 more desirably 11 to 14. The adding amount of said surface active agent may be commonly 0.05 to 8% by weight, desirably 0.1 to 5% by weight.
Thickener should be added in said metal corrosion inhibitor of the present invention to ensure enough thickness of the coating layer of said treatment solution on the surface of said metal to be treated. Said thickener, used for this invention, is a water-soluble thickener comprising methyl cellulose, carboxymethylcellulose, hydroxymethylcellulose, ethyl cellulose, carboxymethylcellulose, hydroxyethylcellulose, poly(vinyl alcohol), starch, nonionic starch, pectin, guar gum, tamarind gum, locast bean gum, galactomannan, carrageenan, agar and the like. Further said carboxymethylcellulose, hydroxymethylcellulose, and hydroxyethylcellulose are more preferable as a thickener. The adding amount of said thickener may be commonly 0.05 to 5% by weight, desirably 0.1 to 1% by weight.
Water used to prepare said treatment solution of said metal corrosion inhibitor in the present invention may be such as distilled water, deionized water, further boiled city water and the like.
Since said treatment solution in said self-sacrifice type metal corrosion inhibitor of the present invention is nearly neutral, it is desirable to add a sterilizer to inhibit propagation of many kinds of microorganism such as bacteria, fungus, yeast, duckweed, and the like in the case of a long time storage. Said sterilizer to be selected has preferable compatibility with other components used in said treatment solution.
Said sterilizer used in the present invention may be isothiazoline and its derivative, organonitrogen-sulfur compound, organonitorogen compound, organonitrogen halogen compound, chlorohexidine salt, mixture of organonitrogen compound and organo sulfur halogen compound, mixture of organonitrogen compound and organonitrogen sulfur compound and the like. Desirable sterilizer may be isothiazolin and its derivative and chlorohexydine salt. Adding amount of said sterilizer may be commonly 0.01 to 5% by weight, desirably 0.01 to 1% by weight.
It is preferable to add on aqueous organic solvent to improve dispersing stability together with said anticorrosion agent and said surface active agent in said treatment solution of said corrosion inhibitor of the present invention. Said aqueous organic solvent may be 1-propanol, 2-propanol, primary butanol, secondary butanol, tertiary butanol, ethyleneglycol, diethyleneglycol, propyleneglycol, dipropyleneglycol, glycerol, methylcellosolve, ethyllcellosolve, butylcellosolve, methylcarbitol, ethylcarbitol, butylcarbitol, butyleneglycol, 2-ethyl-1,3-hexanediol, neopentylglycol, 1,5-pentanediol, 2,3-dimethyl-2,2-butanediol, and ethyleneglycol-mono-t-butyl ether, diacetone alcohol and the like. Further, said glycerol, ethyleneglycol, diethyleneglycol, propyleneglycol, butyleneglycol, dipropyleneglycol, 2-ethyl-1,3-hexanediol, and 1,5-pentanediol are more desirable as an aqueous organic solvent. Adding amount of said aqueous organic solvent may be commonly 3 to 40% by weight, desirably 8 to 35% by weight.
Said treatment solution of said corrosion inhibitor may be prepared by mixing said metal powder, said surface active agent, said water insoluble thermoplastic resin powder, said thickener and water, and desirably said aqueous organic solvent, said anticorrosion agent, and said sterilizer and stirring enough to disperse said metal powder in said treatment solution and the viscosity of said treatment solution is commonly adjusted 40xc2x15 sec by Iwata Ford cup #4. To treat the surface of said metal to be treated, first the surface of said metal is polished by shot blast, sand blast and the like and then desirably washed by an organic solvent such as n-hexane, xylene, methylethyl ketone, acetone, and the like followed by drying.
After that, said treatment solution is coated on the surface of said metal by dipping, spraying, roll coater, curtain flow coater, rotating blush coater, electrostatic coating and the like. After coating, said metal is kept at room temperature if necessary with blowing against said metal to dry and heat at a temperature between 150 to 160xc2x0 C. for at least 10 minutes for predrying and then at a temperature between 230 to 240xc2x0 C. for at least 10 minutes for main drying.
A self-sacrifice type metal corrosion inhibiting layer is formed on the surface of said metal by said treatment.
If desirable, paint may be further coated on said corrosion inhibiting layer. Further, aqueous paint can be prepared by adding inorganic pigment instead of said metal powder when said treatment solution is prepared and said aqueous paint can be used for coating on said corrosion inhibiting layer instead of common paint.
On said corrosion inhibiting layer, self-restoring treatment by using a self-restoring agent having self-sacrifice type corrosion inhibiting property may be desirably effected. Mixture, which is used for said self-restoring agent, comprises Na2O:nSiO2 (n=3 or 4) and polymer and/or oligomer which is one or more polymer and/or oligomer selected from the group consisting of poly acrylic and/or methacrylic acid (hereinafter referred to as (meth)acrylic acid), copolymer of (meth)acrylic acid and other vinyl monomer which can be copolymerized with (meth)acrylic acid, (meth)acrylic acid oligomer, and oligomer consisting of (meth)acrylic acid and other vinyl monomer which can be copolymerized with (meth)acrylic acid
As said other vinyl monomer which can be copolymerized with (meth)acrylic acid, one or more vinyl monomer can be used, wherein said one or more vinyl monomer is(are) one or more vinyl monomer comprising methyl (meth) acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth)acrylate, and diethylaminoethyl (meth)acrylate and the like. One or more kinds of said self-restoring agents may be used together.
Said self-restoring agent may be added in an amount of 0.1 to 20% by weight, desirably 1 to 5% by weight as a resin component of said polymer, and/or said copolymer and/or said oligomer, and Na2O:nSiO2 may be added in an amount of 20 to 45% by weight, desirably 25 to 35% by weight as SiO2.
By said self-restoring treatment, self-restoring property equal to or higher than that of zinc-chromate treatment layer can be given on said metal corrosion inhibiting layer.

Self-sacrifice type metal corrosion inhibitor and a metal corrosion inhibiting method

Institute of Technology Precision Electric Discharge Work""s


The caster wheel having integrated electrical brake involves a standard caster wheel and an electronic braking component that screws into the top surface of the caster wheel mounting bracket. The electrical braking component includes a solenoid that moves a pin up and down to impact a spring-loaded brake mounted underneath the caster wheel mounting bracket.

A. Field of the Invention
The present invention relates to the field of caster wheels, more specifically, a caster wheel with an electrical braking system.
B. Discussion of the Prior Art
As a preliminary note, it should be stated that there is an ample amount of prior art that deals with caster wheels. As will be discussed immediately below, no prior art discloses a caster wheel with an integrated electrical braking system.
The Lange Patent (U.S. Pat. No. 5,184,373) discloses a caster wheel for a dolly or a cart that has an electrically activated brake which prevents rolling and turning movement of the wheel. However, the caster wheel braking system is not a component that screws into the top mounting bracket of the caster.
The Strong Patent (U.S. Pat. No. 7,159,695) discloses a dampening or braking system for a wheel for a dolly or a cart in which an electrically controlled pin is activated to press against the wheel. Again, the electrically controlled braking system is not a component that screws into the top mounting bracket of a caster wheel.
The Lin Patent (U.S. Pat. No. 6,834,746) discloses a caster wheel braking system in which a pin or other device is pressed against the wheel to prevent movement. However, the pin presses against a lower cam and disk that act as a brake to stop or impede the rotational movement of the caster wheel.
The Milbredt Patent (U.S. Pat. No. 6,584,641) discloses a manually operated brake and steering lock for the caster wheel of a rolling device in which a person presses a spring activated tab against the wheel. However, the manually operated brake is not electrically operated, and is not a component that is screwed into the top mounting bracket of the caster wheel.
The Neumann Patent (U.S. Pat. No. 4,414,702) discloses a device for preventing the movement of a caster wheel from rolling and swiveling in which a device is pressed against the wheel. However, the locking device does not attach to the top surface of the caster wheel mounting bracket.
While the above-described devices fulfill their respective and particular objects and requirements, they do not describe a caster wheel electronic braking system that screws into the top surface of the caster wheel mounting bracket. In this regard, the caster wheel having integrated electrical braking means departs from the conventional concepts and designs of the prior art.

Caster wheel having integrated braking means


Methods for assembling fiberglass reinforced plastic sucker rods include transporting fiberglass reinforced plastic sucker rod sections from an off-site location to an assembly facility at or near a point of use, and providing a sufficient number of metallic end fittings to connect respective ends of the plurality of sucker rod sections in series at the assembly facility. Systems for assembly of sucker rods from sucker rod sections transported from off-site location to or near a point of use are also described.

Fiberglass reinforced plastic (FRP) sucker rods and present manufacturing methods are discussed in various public resources, such as U.S. Pat. No. 7,730,938, to Rutledge, Sr. It is assumed the reader is familiar with FRP sucker rods and their use. As will be noted by reviewing the '938 patent, the known manufacturing process involves many steps. Manufacture of the FRP rod sections that make up the final, complete FRP sucker rod relies on a very expensive pultrusion machine and labor-intensive process. It is an object of the present disclosure to perform only certain assembly steps of a completed FRP sucker rod at or near a point of use, such as at or near a producing hydrocarbon basin, thus reducing the need to purchase and operate an expensive rod section pultrusion machine at such points of use, or to transport completed FRP sucker rods long distances to such points of use, with attendant worries of damage to the rods prior to use.
In addition to the above-mentioned problems attendant to the remote manufacture of FRP sucker rods (both jointed and continuous), the present inventor has noted that the known methods of attaching metallic end fittings to abraded fiberglass rod section ends was in need of improvement. In particular, almost no disclosure has been made of particular abrading materials or methods, or of adhesives used in attaching the end fittings to the abraded ends of the FRP rod sections. The '938 patent provides no teaching or details on these issues.
An additional problem faced by the FRP sucker rod assembler, and so far as can be seen in the patent literature, an underappreciated fact, is that the FRP rods stretch during assembly. In one known assembly process, according to the '938 patent, after the adhesive is applied to the end fitting and the end fitting applied to rod end, the end fitting area is heated to cure the adhesive, and then cooled or allowed to cool. As explained in the '938 patent, the cooled rods are then "pull tested" (pulled longitudinally) to set the mechanical wedge bond between the cured adhesive and the end fitting. According to the '938 patent, the pull test both creates and checks the integrity of the mechanical bond between the rod body and the end fitting. What is not discussed is how the pull test is performed (by a hand crank mechanism), or that the rod itself undergoes stretching during the pull test, the degree of stretch depending on the tension three applied, the type of FRP material, diameter of the rod, and so on. In some instances, the present inventor is aware that a nominal 37 foot (11.3 m) length rod may be stretched up to 11 inches (28 cm) or more. Monitoring and measurement of rod stretch is not currently practiced during pull testing, as far as is known, because the hand crank method and apparatus is not set up to measure this. Although the stretch could be measured by hand, it would be beneficial to know the actual rod stretch measurement precisely, since an FRP rod that stretches even a little too much or too little will be compounded over the length of the connected rods down hole. FRP rods that stretch too much may be an indication that they do not have enough longitudinal glass fiber roving, and therefore may not endure many pumping cycles during use; on the other hand, FRP rods that stretch too little may have too much glass fiber roving, and therefore may be too rigid for many down hole applications, or may not be suitable for winding onto to spools.
The industry has long lived with the above-mentioned problems and has accepted them as facts of the business. There is thus a long-felt but as yet unmet need in the art of assembling FRP sucker rods for methods and systems alleviating these problems. Note that while the '938 patent mentions that end fittings may be attached to a sucker rod at a field location, and that several "conventional" steps can be performed, such as "additional quality control checks or inspections", there is no description of or directions given how pull testing and stretch measurement would be accomplished at a field location.

Methods and systems for assembly of fiberglass reinforced sucker rods


An electrical connector is provided with electrical contacts comprising three contact zones or regions. The primary contact region is planar and parallel with the axis of insertion when two identical hermaphroditic connectors are mated. The tip of the contact assembly is formed to create a second contact zone and a third contact zone is formed at the same orientation as the second contact zone and disposed to be engaged by the second contact zone of the mating contact assembly. The housing of the connector is keyed to permit connection only with an identically keyed connector housing. The connector is provided with a strain relief formed integrally with the housing to resist the pulling of the conductors from the connector. The contact assembly engages the wire in the conductor when final assembly occurs, by means of a double insulation displacement contact.

Hermaphroditic electrical connectors are desirable because the mating nature of the connectors is such that only one design of the connector element need be manufactured and then multiple connector elements may be used by merely reversing them and inserting them into a second identical connector. Connectors of the hermaphroditic type are typically used in cases where there is a requirement to assemble and disassemble the connector or to make an electrical connection and then disconnect the electrical connection on a repeated basis. The connector must be reliable and provide a high quality electrical contact when assembled. The electrical connector housing or module must capture the wires which extend from the connector housing and at the same time provide a strain relief to insure that the electrical wires are properly maintained in contact with the electrical contact elements within the housing.

International Business Machines Corporation


The present disclosure relates to the technical field of mechanical precision manufacturing, in particular to a motor tracking error reduction method and an implementation device based on a micro-drive unit. A motor tracking error reduction method based on micro-drive unit includes: providing a motor mover as the working output end, and feeding back the position information of the motor mover to the micro-drive controller in real time by the sensor; controlling the micro-drive unit to compensate the displacement of the motor mover by the micro-drive controller; correcting the tracking error of the motor mover after the displacement compensation, and feeding back the tracking error information after correction to the motor controller. The error reduction method and implementation device in the present disclosure reduce the motor tracking error and solve the problem of coupling interference. In addition, the single position feedback is used to reduce the production cost.

With the progress of science and technology, the performance of products is improving, and the requirements of processing accuracy of corresponding products are also higher and higher. Wherein, the motor is widely used in various manufacturing and processing equipment, such as laser cutting machine, machine tool, semiconductor manufacturing equipment and so on.
At present, due to the uncertainty of mechanical/electrical parameters, thrust fluctuation, nonlinear friction and other problems in the motor system, the position tracking error is large in the process of motor motion. In the existing equipment, the stroke of high-precision micro motion platform is generally short, and the precision of ordinary macro motion equipment with large stroke can not meet the actual demand. If the special large stroke high-precision motion equipment is used, the manufacturing cost of the product will be greatly increased. Therefore, the method of combining general precision macro motion with high-precision small stroke micro motion is mainly used to realize large stroke and high-precision feeding, so as to reduce tracking error.
However, in the existing technology, micro motion is used as the output working end to achieve high tracking accuracy. The workpiece is placed on the micro motion part, and after the micro motion part reaches the expected location, the controller drives the micro motion part to compensate for the displacement movement of the macro motion part, but the tracking error of the motor mover in this compensation method does not reduce. At the same time, the macro and micro motion system needs dual position feedback, which will increase the detection cost of absolute sensor. In addition, in practical application, for the feeding of large workpiece, the workpiece is placed on the micro motion platform, and the mass of micro motion part can not be ignored. When micro motion is used for displacement compensation, the coupling interference is difficult to eliminate for macro motion, which increases the complexity of macro motion controller and deteriorates the trajectory accuracy.

Motor tracking error reduction method and implementation device based on micro-drive unit


Disclosed are a computer-based tutoring method and system in which an animated tutor, an animated avatar, and at least one animated group member selected by a user are displayed on a screen. A tutorial is presented by the animated tutor. During the tutorial, an interactive question is presented. An answer is received from the user. If the answer is correct, the tutorial continues. If the answer is incorrect, a second tutorial is presented. The second tutorial is based on the incorrect answer received from the user. Dialog between the animated tutor, the animated avatar, and the animated group members may be held. Dialog among animated group members may be held.

The present invention relates generally to education systems, and more particularly to computer-based tutoring methods and systems.
In a traditional education system, an instructor and a group of students meet in a classroom. The instructor gives a lecture, and the students listen. How well a student learns the subject is gauged periodically by grades on homework and tests. Although the traditional education system has been entrenched for centuries, it inherently suffers from a number of deleterious constraints.
One constraint is access. Access to the traditional education system is limited to students who can travel to the classroom and whose schedule may accommodate a specific class. For a full-time student, access is not an issue. For part-time students, including employees receiving professional training, however, travel, schedule, and attendant expenses restrict the opportunities for classroom instruction.
Another constraint is limited opportunity for instructor-student interaction. Lectures are traditionally structured in fixed periods and follow a specified pace to fit within the allotted time. Often there is limited opportunity for questions and answers. Since individual students learn at different paces and may have questions on different portions of the subject, classroom instruction often does not meet the needs of individual students (in contrast to students in aggregate). A related issue is timeliness of feedback. As discussed above, students are evaluated on the basis of grades on homework and tests. Deficiencies in students' understanding of the subject matter are uncovered after they have received poor grades. Depending on the frequency of the homework and tests, students may struggle with new material because they have not yet mastered the previous material. They then must perform remedial study and play catch-up with the current material being taught in class.
Computer-based instruction has provided a more flexible mode of education. One option is software locally installed on an individual personal computer. With the advent of high-speed Internet connections, another option is software loaded on a central server (or system of servers), which may be accessed from remote locations. Access is then no longer constrained by distance and time. Computer-based instruction, however, often shares some of the same limitations as traditional classroom instruction. In particular, instruction modules are highly structured, and students' understanding of the material is tested at periodic intervals (at the end of each module, for example). What are needed are computer-based tutoring methods and systems which adapt to the learning skills of individual students and which provide rapid evaluation of students' performance.

Computer-based tutoring method and system


A scroll type hydraulic machine is provided with a scroll unit received in a housing, and a thrust bearing arranged between a movable scroll of the scroll unit and a support surface of the housing and receiving a thrust load of the movable scroll, and the thrust bearing includes a plurality of circular retention holes formed in the support surface, and sliding discs rotatably fitted into these retention holes and sliding with respect to both inner surfaces of the retention holes and the movable scroll.

1. Field of the Invention
The present invention relates to a scroll type hydraulic machine, and more particularly to a hydraulic machine preferably used as a compressor for a refrigerating circuit incorporated in an air conditioning system of a vehicle.
2. Description of the Related Art
This kind of scroll type compressor is provided with a housing, and a scroll unit arranged in the housing, and the scroll unit includes a stationary scroll and a movable scroll. These scrolls cooperate with each other so as to form compression chambers, and the compression chambers are intermittently connected to a refrigerating circuit, that is, a refrigerant circulating path.
In more detail, the movable scroll executes a revolving motion with respect to the stationary scroll in a state in which the movable scroll is inhibited from rotating on its own axis. The revolving motion of the movable scroll executes a series of processes from a suction of the refrigerant to the compression chamber from the circulating path to a compression and discharge of the refrigerant, and the discharged compression refrigerant is delivered to a condenser of the refrigerating circuit through the circulating path. In this case, the refrigerant sucked to the compression chamber is supplied from an evaporator of the refrigerating circuit.
Since a pressure of the refrigerant becomes very high in the compressing process of the refrigerant, the compressed refrigerant in the compression chamber applies a large reaction force, that is, a thrust force to the movable scroll. The thrust force operates so as to drag away the movable scroll from the stationary scroll, and hinders a smooth revolving motion of the movable scroll.
Accordingly, the compressor is provided with a thrust bearing supporting the movable scroll with respect to the housing, and the thrust bearing is disclosed, for example, in Japanese Unexamined Patent Publication No. 8-338377.
The thrust bearing in the publication includes a ring-like thrust plate, and this thrust plate is fixed to the movable scroll. The thrust plate is in sliding contact with a support surface of the housing so as to transmit a thrust fore to the housing during the revolving motion of the movable scroll.
Since a structure of the thrust plate is simple in comparison with a rolling bearing, the thrust plate is obtained inexpensively, however, can not sufficiently lower a sliding resistance of the movable scroll, so that an electric power consumption of the compressor is increased.
On the other hand, in the case that the scroll compressor is driven by an engine of a vehicle, the thrust load of the movable scroll is largely fluctuated on the basis of a rotating speed of the engine and a drive condition of the compressor.
Accordingly, it is necessary that this kind of thrust plate can sufficiently resist the great fluctuation of the thrust load. More specifically, the thrust plate is formed by a material having high hardness, and a sliding surface of the thrust plate in a side of the support surface is ground or coated. Therefore, the thrust plate has the sliding surface with a small friction coefficient. For example, the coating for the thrust plate is formed by nickel and phosphor plating, Teflon or the like disclosed in the publication.
The thrust plate mentioned above has an outer diameter which is approximately equal to that of the movable scroll, and is a comparatively large part in view of constituting parts of the compressor. Accordingly, since a lot of labor hour is required for grinding and coating the thrust plate, not only a productivity of the compressor is deteriorated, but also a cost of the compressor is increased.
Further, even if the sliding surface of the thrust plate is coated, a conjunction between the coating and a base material of the thrust plate is weak. Accordingly, the coating is peeled off from the thrust plate during the drive of the compressor, and the sliding resistance of the thrust plate is increased.


A coating system includes a work piece, a coating delivery apparatus configured to apply a coating material to the work piece in a plasma-based vapor stream, and a first electron gun configured to direct a first electron beam at the plasma-based vapor stream for adding thermal energy to the coating material in the plasma-based vapor stream.

The present invention relates to coating apparatuses and methods of applying coatings.
Coatings are utilized in a variety of settings to provide a variety of benefits. For example, modern gas turbine engines can include thermal barrier coatings (TBCs), environmental coatings, etc. to help promote efficient and reliable operation. Application of coatings can involve a variety of different application methods, such as plasma-based physical vapor deposition (PVD). When TBCs are applied to gas turbine engine components, such as blades and vanes, using plasma-based-PVD, the components being coated are rotated within a process chamber while a plasma stream directs a vapor stream of the coating material at the components. Examples of such known coating processes are disclosed in U.S. Pat. No. 7,482,035 and in U.S. Pat. App. Pub. Nos. 2007/0259173A1 and 2008/0226837A1.
A significant problem with known plasma-based PVD processes is the loss of heat. Plasma-based PVD coating processes have substantial difficulty managing spontaneous nucleation of coating particles at the periphery of the coating material vapor stream. Such spontaneous nucleation occurs at the periphery of the vapor stream where temperatures become cool enough for the formation of liquid and/or solid ceramic particles. When liquid and/or solid ceramic particles impinge the work piece, those liquid and/or solid particles detrimentally interfere with the formation and growth of desirable TBC microstructure. Specifically, solid spherical particles become entrapped in the growing TBC and disrupt desired columnar growth of ceramic crystals. A similar problem occurs when liquid ceramic impinges against the work-piece during columnar crystal growth; the development of proper TBC microstructures is disrupted by the discontinuity that results from droplets of ceramic that adhere and freeze to the work piece.
One approach known in the art for providing temperature control involves passive thermal shielding. However, passive thermal shielding mitigates only off-axis heat loss to a relatively cold process chamber. Known passive thermal shielding may be insufficient to sufficiently maintain coating materials in a vapor state for deposition on work pieces.

Thermal stabilization of coating material vapor stream


Systems and methods for tracking ammunition supply in a magazine are disclosed herein. A method for tracking a number of cartridges remaining within a magazine includes tracking an indicator strip coupled to a spring housed within a magazine housing, the magazine housing having the spring coupled at a first end to a follower and at a second end to a foot plate, the spring tangent to the foot plate. The method further includes selectively altering a number of cartridges in the magazine housing and monitoring an indicator window attached to the foot plate and configured to guide the indicator strip, the indicator strip aligned with a reference on the indicator window showing the number of cartridges remaining.

With the increasing complexity of small arms weapons systems and the increasing complexity of urban warfare, the importance of knowing the ammunition count within a weapon's ammunition magazine becomes more relevant. Death or serious bodily injury may result if an operator of a weapon with a magazine runs out of ammunition in the duration of a small arms altercation. Current magazines with full metal casings do not allow for a direct view into the ammunition storage inside a magazine, while plastic magazines allow a limited view at the ammunition source, but not beyond where the magazine goes into the weapon and is covered by the magazine well of the weapon. In many situations, knowing when a magazine is at its last five to ten rounds is more crucial than knowing when it has lost its first five to ten rounds, as usually indicated to a limited degree by most clear magazines, in the decision process for tactical magazine replacements.
Several strategies have been developed to aid the decision to change magazines in a weapon. One of the more popular is to add tracer ammunition at a predetermined count of ammunition. However, the disadvantage of this method is that in warfare, tracer ammunition can potentially create fires in buildings. Also, besides warning the operator of the weapon of the low ammunition count, tracers can likewise warn the operator's adversaries of the operator's position in the battlefield, which could be catastrophic for the operator. Furthermore, the use of tracer ammunition does not communicate the actual ammunition count to the operator, but just a warning of a low count of it.
Another method devised to aid with the magazine replacement decision process is keeping mental track of a magazine's remaining ammunition. By keeping a count, even if not with complete accuracy, an approximation of the count will provide enough information for the magazine change decision process. However, with the intensity and high stressfulness of small arms altercation situations, this becomes an impractical practice, as even an operator's momentary loss of focus could lead to the loss of count. Likewise, if the magazine that the operator is using does not contain the initial amount of ammunition that he or she believes it initially does, the basis for which the magazine replacement would occur will be faulty.
One of the more popular methods for deciding a magazine change is for an operator to estimate the amount of ammunition he or she has based on the weight of his or her weapon with ammunition. To a limited extent, this may be a useful approximation, however with the incorporation of different add-ons onto the operator's weapon, such as night sights, scopes and other accessories, the operator's judgment of the count can be hindered, increasing the liabilities associated with this method.
Understanding some of the limitations to the current systems and methods for keeping track of unspent ammunition, one embodiment of the present invention is devised to eliminate the risks caused from the overestimation of one's ammunition count, while avoiding the waste of ammunition caused by the premature replacement of magazines due to underestimation. By doing so, the aims of one embodiment of the present invention include, but are not limited to making the use of the ammunition within a given as efficient as possible with little compromise to the magazine's weight or profile, by aiding an operator in his or her decision process for changing magazines in high stress situations.


A method of forming an element to float at least partially on a surface of an at least partially liquid hydrocarbon mixture. The method includes mixing a polymer resin and a foaming agent together in preselected proportions to provide a material mixture, and heating the material mixture, to at least partially liquefy it. The material mixture is injected into a mold cavity configured to define the element's exterior surface in a series of at least three steps, commencing with an initial step. In each step, the material mixture is injected over a predetermined time period at a predetermined velocity and under a predetermined pressure. Each predetermined velocity in the steps following the initial step is less than the predetermined velocity in an immediately preceding step thereof. Each predetermined pressure in the steps following the initial step is less than the predetermined pressure in the immediately preceding step thereof.

As is well known in the art, oil field collection tanks are used as loading points for oil collected from conventional heavy and mid to light crude oil wells. The field collection tanks allow the operator to have a mixture including crude oil (as hereinafter described) flow from the subsurface formation, via the well, to the Earth's surface (i.e., the collection tanks) at a natural flow rate, or at a pump-assisted flow rate. The mixture accumulates in the tank until sufficient volume is in the tank to trigger level instrumentation inside the tank, which then signals that the volume of accumulated crude oil has reached a predetermined level. Typically, a tanker is then sent to the site in response to the signal to remove the accumulated crude oil from the collection tank. The oil is transported by the tanker to larger storage tanks, where it is stored until processed.
Typically, the crude oil accumulates in the collection tank over an extended period of time, e.g., several days, before a volume sufficient to cause the signals to be sent that request the tanker to remove crude oil from the collection tank.
The mixture that flows from the subsurface formation usually includes water and sediment. ("Sediment" herein refers to all foreign (non-crude oil) material other than water in the mixture.) Where the crude oil is heavy crude oil, it is desirable that the mixture that accumulates in the collection tank be treated (i.e., "conditioned") while it is in the collection tank, to separate at least part of the water and sediment from the crude oil. Such separation permits more efficient processing of the crude oil subsequently.
The treatment, or conditioning, involves maintaining the crude oil at an elevated temperature (e.g., approximately 80° C.). Due to such conditioning, over a relatively short time period, the water and sediment separate from the heavy crude oil, and stratify, i.e., they also substantially separate from each other. As is known in the art, the heat facilitates the separation of the heavy crude oil, the water, and the sediment, under the influence of gravity. The heat reduces the viscosity of the heavy crude oil sufficiently to permit the sediment to separate from the crude oil, under the influence of gravity. The separation of the crude oil from the water and sediment typically begins upon introduction of the mixture into the container. However, in order for the separation (i.e., the conditioning) to be substantially completed, it appears that the mixture needs to reach a temperature of approximately 80° C.
FIG. 1A is a cross-section of a collection tank 10 of the prior art showing, for purposes of illustration, a mixture 12, i.e., prior to conditioning thereof. In FIG. 1B, the results of the conditioning are shown. (As will be described, the remainder of the drawings illustrate the present invention.) Due to the conditioning, the mixture 12 shown in FIG. 1A has separated into heavy crude oil 14 positioned above water 16 and sediment 18. Those skilled in the art would appreciate that the mixture as shown in FIG. 1A, and the stratification of the mixture as shown in FIG. 1B, are somewhat simplified for the purposes of illustration. In FIG. 1A, a surface 19 of the mixture 12 is identified. In FIG. 1B, a surface of the heavy crude oil 14 is identified by reference numeral 19′ for clarity.
Because of the conditioning, the water and sediment are generally separated from the heavy crude oil in the collection tank. Having a density of about 0.92 g/cc (57.4 lbs./cu. ft.), the heavy crude oil is less dense than the water and the sediment. Accordingly, once the mixture has been conditioned, the water and the sediment are separated, and positioned below the heavy crude oil so that the tanker can remove only the "conditioned" crude portion to the processing facility (FIG. 1B). As is well known in the art, after the heavy crude oil is removed, the accumulated water and sediment are removed separately.
In practice, where an oil well produces crude oil at a relatively rapid rate, the mixture may not be allowed to remain in the container long enough to reach the desired conditioning temperature of 80° C. In this situation, due to the relatively small capacity of the container in view of the well's production rate, the crude oil is removed from the container of necessity, however, the removal may take place before the preferred temperature of 80° C. is achieved. One consequence of this is that the viscosity of the crude oil is relatively high while it is in the container, and for this reason, smaller pieces of sediment remain trapped in the crude oil. That is, if the mixture doesn't remain in the container long enough to reach 80° C., the conditioning is not completed. These trapped impurities ultimately result in higher processing costs.
Existing field collection tank designs typically include thermal insulation on the outside of the tank and a source of heat (e.g., a gas-fired direct burner heater) (not shown in FIGS. 1A and 1B) mounted on the field tank to maintain the mixture's temperature at, or close to, the ideal temperature of approximately 80° C. which is required for oil conditioning during accumulation. However, because the desired temperature is elevated, heat is lost from the mixture to the surroundings. Accordingly, one disadvantage of the prior art is that the heat loss results in increased operational costs, due to energy inputs required for additional heat, to replace the heat lost to the surroundings.
As noted above, another disadvantage of the prior art is that, when the crude oil production rate requires that the container be emptied relatively frequently, the mixture is not properly heated (i.e., to 80° C.) before the heavy crude oil is removed.
Much of the heat loss from the mixture is from the surface thereof, partially (but not entirely) due to vapours escaping therefrom. The vapours contain many light hydrocarbon compounds, generally known in the industry as BTEX. These vapours contain carcinogens and therefore pose a health risk. Also, their escape from the collection tank is a vehicle for the loss of a great deal of thermal energy. As is well known in the art, the collection tanks are not pressure vessels and are vented to the atmosphere, to allow the liquid level to change without causing a pressure or vacuum condition to occur. In FIGS. 1A and 1B, vapours and thermal energy escape from the collection tank via the headspace "H" as schematically indicated by arrow "A". Accordingly, the escape of such vapours from the container is another disadvantage of the prior art.
Depending upon the oil well, there may be natural gas and other vapours that percolate up in the mixture in the collection tank, and these gases can cause the mixture (or, after separation, the heavy crude oil) to froth. This oil froth or foam, which can become relatively thick in elevation above the actual liquid surface, can cause the liquid level instrumentation to generate a false high level indication and prematurely shut down the oil well pump prior to the field tank actually being full. To prevent this, current practice is to employ chemical surfactant additives via dosing systems at each of the well locations, to administer the chemical surfactants into the flow of the mixture that will reduce frothing inside the storage tanks. However, the chemical surfactants also contain BTEX and carcinogenic chemicals that are undesirable, and consequently put operators at risk.
Also, the chemical surfactant additives, by their nature, reduce the heat transfer efficiency of any thermal equipment that comes into contact with the heavy crude oil, thereby making heat transfer processes less energy efficient. That is, because surfactants reduce surface tension, their use tends to result in more laminar flow, i.e., correspondingly less turbulent flow. Because energy transfer to the liquid is more efficient where the liquid is subject to turbulent flow, the use of surfactants generally tends to result in less efficient transfers of energy, e.g., heat energy. Accordingly, elimination of the chemical surfactant additives would be advantageous, because it would save costs, increase thermal efficiency and eliminate certain health risks to operators.
Floating segmented covers are known that typically are made from recycled polypropylene/high-density polyethylene (HDPE) or polyethylene (PE) that is chemically foamed to a specific gravity of at least 0.5 (i.e., a density of not less than 0.5 g/cc (approximately 31.2 lbs./cu. ft.)). This density is due to the nature of the material and technical and processing limitations, as is known in the art. These covers are made of several cover components and are only intended for water and wastewater applications, where the specific gravity of the fluid covered is approximately 1.0. With a specific gravity of 0.5 (i.e., a density of approximately 0.5 g/cc (approximately 31.2 lbs./cu. ft.)) these prior art cover components initially can float on the surface of an aqueous liquid with the liquid waterline positioned substantially at the center of the cover component. For instance, the wastewater may include manure, and the cover is intended to impede and obstruct the release of noxious odours and potentially harmful vapours from the wastewater.
However, it has been found that, over time, the prior art cover components absorb and/or adsorb water into the cellular structure of the foamed polymer. They therefore become heavier (i.e., more dense) over time. When the specific gravity of the cover component is greater than 0.5 (i.e., a density of 0.5 g/cc (approximately 31.2 lbs./cu. ft.)), the liquid level is above the vertical center of the cover component, i.e., allowing liquid to be above at least part of the cover component. At that point, the cover components are no longer covering the surface of the wastewater, and the odours and vapours escape from the wastewater. It can be seen, therefore, that the prior art foamed polypropylene, HDPE, or PE cover components are effective for only a limited period of time when they are used on water.
The prior art foamed polypropylene covers have been tested in the heated (or "conditioned") mixture of heavy crude oil, water, and sediment described above. Such prior art covers have been found to be unsatisfactory in this context, for a number of reasons. In particular, the prior art covers tend to sink within a relatively short time after being positioned on the heated mixture. Based on the testing done to date, it appears that there are at least three distinct reasons why the prior art covers do not function properly when positioned in and on the mixture in the collection tank.
First, the density of the prior art cover components is too high. The a hydrocarbon liquid mixture typically has a specific gravity of about 0.8-0.9 (i.e., a density of about 0.8-0.9 g/cc (approximately 49.9-56.2 lbs./cu. ft.)). In order for the cover component to be less than about 50 percent submerged initially, the prior art cover component would need a specific gravity less than about 0.5 (i.e., a density of less than about 0.5 g/cc (approximately 31.2 lbs./cu. ft.)). Accordingly, the prior art cover components tend to sink when positioned on the mixture. Due to the configuration of the cover components (i.e., generally wider in the middle), when the cover component is more than about 50 percent submerged, the mixture is on top of at least part of the cover component, and the cover components do not substantially cover the surface.
Second, it is believed that the heavy crude oil is relatively quickly absorbed and/or adsorbed into the foamed cellular structure of the prior art cover components. The prior art chemically foamed polymer cover components, made of polypropylene or polyethylene (as described above), appear to allow the diffusion of hydrocarbons and water through the cellular structure of the polymer wall thereof relatively quickly. This causes the prior art cover component to gain weight relatively quickly and sink further into the liquid, quickly rendering it largely submerged and ineffective.
Third, the prior art foamed polypropylene, HDPE, and PE cover components are not chemically compatible with the hydrocarbons, i.e., these materials are soluble in hydrocarbons. In particular, the elevated operating temperatures encountered in the crude oil collection tanks tend to accelerate the polypropylene, HDPE, and PE degradation.

System for covering hydrocarbon liquids and method of forming same

Greatario Industrial Storage Systems Ltd.


An electric sanding machine has a housing with a drive device disposed therein, a base plate disposed under the housing, and a driven shaft for driving the base plate. A sanding device is attached to the base plate. The housing has a drive device housing part substantially perpendicular to the base plate and a grip housing part substantially parallel to the base plate. A cross section of the housing in a vertical direction is substantially L-shaped. The drive device is disposed in the drive device housing part while the driven shaft is located in the grip housing part so that the drive device is departed from the driven shaft in a radius direction of the driven shaft. With this arrangement, the sanding machine is provided with stronger power and has a smaller contour size which may be controlled more effectively.

The following generally relates to a portable power tool and, more particularly, relates to an improved electric sanding machine.
In the art of power tools, electric sanding machines are known. A commonly used electric sanding machine shown in FIG. 1 comprises a housing 1, a base plate 2 with an abrasive sheet attached thereon, and handles mounted on the housing. For convenience of operation, a main handle 3 and an auxiliary handle 4 are respectively connected to the rear side and the front side of the housing 1. A dust vent 5 is defined on the rear side of the housing 1 for permitting escape of dust created due to the sanding operation and sucked from holes (not shown) on the base plate.
To satisfy requirements of sanding power, the above described sanding machine typically is installed with a relatively large sized motor which occupies a lot of space and increases the height of the sanding machine. Furthermore, the above structural arrangement results in a sanding machine with the main handle being positioned near the top of the housing which is not on the line of the gravity center of the machine which thus causes the sanding machine to be difficult to control effectively only by gripping the main handle. While the operator may grip both the main handle and the auxiliary handle with two hands to smoothly perform the sanding operation, there is a disadvantage in that the operator no longer has a free hand to do other assistant work for the sanding operation. The above structural arrangement further results in the operation position being far from the working surface which also makes the machine not very easy to control to achieve a good work especially when a surface to be sanded is on a special position, such as ceiling, vertical wall, object in a narrow space, and so on. Still further, in order to collect the dust escaping from the dust vent, the dust vent is commonly connected with a dust collection box or an exhausting duct which also increase the contour size of the sanding machine.


Method and apparatus for controlling vibrotactile sensations for haptic feedback devices. An actuator in a haptic feedback device includes a rotatable eccentric mass, and information is received at the haptic feedback device causing a drive signal. The drive signal controls the actuator to oscillate the mass in two directions about an axis of rotation of the actuator such that the oscillation of the mass induces a vibration in the haptic feedback device. The magnitude and frequency of the vibration can be independently controlled by adjusting a magnitude and a frequency, respectively, of the drive signal. The vibrations can also be provided in a bi-directional mode or uni-directional mode to provide the most efficient magnitude of the vibrotactile sensations. The haptic feedback device can be, for example, a gamepad controller receiving commands from a host computer providing a graphical environment.

The present invention relates generally to producing forces in haptic feedback interface devices, and more particularly to the output and control of vibrations and similar force sensations from actuators in a haptic feedback interface device.
Using an interface device, a user can interact with an environment displayed by a computer system to perform functions and tasks on the computer, such as playing a game, experiencing a simulation or virtual reality environment, using a computer aided design system, operating a graphical user interface (GUI), or otherwise influencing events or images depicted on the screen. Common human-computer interface devices used for such interaction include a joystick, mouse, trackball, steering wheel, stylus, tablet, pressure-sensitive ball, or the like, that is connected to the computer system controlling the displayed environment.
In some interface devices, force feedback or tactile feedback is also provided to the user, also known more generally herein as "haptic feedback." These types of interface devices can provide physical sensations which are felt by the user using the controller or manipulating the physical object of the interface device. One or more motors or other actuators are used in the device and are connected to the controlling computer system. The computer system controls forces on the haptic feedback device in conjunction and coordinated with displayed events and interactions on the host by sending control signals or commands to the haptic feedback device and the actuators.
Many low cost haptic feedback devices provide forces to the user by vibrating the manipulandum and/or the housing of the device that is held by the user. The output of simple vibration haptic feedback (tactile sensations) requires less complex hardware components and software control over the force-generating elements than does more sophisticated haptic feedback. One or more motors are mounted in the housing of the devices and are energized to provide the vibration forces. An eccentric mass is positioned on the shaft of each motor, and the shaft is rotated quickly to cause the motor and the housing of the device to vibrate. One problem with these currently-available implementations of vibration haptic feedback devices is that the vibrations that these implementations produce are limited.

Controlling vibrotactile sensations for haptic feedback devices


An inflatable product has a first layer and a second layer, each layer having a peripheral edge, with the first and second layers joined together along their peripheral edges to define an internal space for receiving air or fluid. Each layer has a uniform thickness throughout except that the thickness along the peripheral edge of each layer is greater than the thickness of the rest of the layer. A plurality of tension members can also be provided inside the internal space, each tension member having a first end that is joined to an inner surface of the first layer, and a second end that is joined to an inner surface of the second layer. Each tension member has a uniform thickness throughout except that the thickness along the first and second ends is greater than the thickness of the rest of the tension member.

1. Field of the Invention
The present invention relates to an inflatable product, and in particular, to a connection structure for use with inflatable products.
2. Description of the Prior Art
At present, most of the inflatable products on the market are made up of a top layer and a bottom layer, which are made from environmentally friendly materials, such as PVC and TPU. For example, a current inflatable mattress is generally formed of a top layer having a uniform thickness and strength, a bottom layer, connecting coils that function as tension members, and a surrounding material layer. The top layer and the bottom layer are joined all around, through the surrounding material layer, by means of high-frequency welding, to form a sealed air chamber. A plurality of coils or tension members are joined between the top and bottom layers via high-frequency welding. In this manner, after the mattress is inflated, the top and bottom layers are kept flat under the pull of the tension members, so as to form the desired shape for the mattress. The top layer and the bottom layer typically both have a uniform thickness. When such a product is used, the base positions where the tension members are joined with the top and bottom layers are subject to a maximum stress. In addition, because the base positions where two layers having a uniform thickness and strength are joined by high-frequency welding become thinner due to welding, the stress-resistant strength of the base positions is much lower than that of the positions free from such welding. Therefore, the base positions are most likely to be torn during use, and the service life of the product is thus shortened.
Thus, when inflatable products such as mattresses, inflatable pools, inflatable recreational products, life-saving and protecting products, and the like, are manufactured, it is necessary to improve the tensile strength of the base positions where the top layer and the bottom layer are joined, and to ensure that the joints of the top layer and the bottom layer are unlikely to be damaged during welding. One attempt to address this problem is to uniformly increase the overall thickness of the top layer and the bottom layer. However, this uniform increase in thickness increases the weight of resulting product, making it difficult to carry or transport, and also increases the cost of the product.
There remains a need for an improved connection structure for inflatable products that avoids the drawbacks identified above.

Connecting structure for inflatable products


A CMOS EPROM, EEPROM or inverter device includes an nFET device with a thin gate dielectric layer and a pFET device juxtaposed with the nFET device with a thick gate dielectric layer and a floating gate electrode. The thick gate dielectric layer is substantially thicker than the thin gate dielectric layer. A common drain node connected both FET devices has no external connection in the case of a memory device and has an external connection in the case of an inverter. There are external circuit connections to the source regions of both FET devices and to the gate electrode of the nFET device. The pFET and nFET devices can be planar, vertical or FinFET devices.

This invention relates to Complementary Metal Oxide Silicon (CMOS) Electrically Programmable Read Only Memory (EPROM) and CMOS EEPROM (Electrically Erasable and Programmable Read Only Memory) devices, which are especially suitable for embedded applications.
In many applications, particularly in System-on-Chip (SoC) applications, designers want to have a certain number of embedded non-volatile memory devices on the microprocessor or Application-Specific Integrated Circuit (ASIC) chips. The preferred approach for meeting this need is to provide embedded non-volatile memories that require little or no additional process cost to the base logic technology. Often, the additional requirements for such embedded non-volatile memories are high density, i.e. small cell size, low power, and high speed.
In a regular CMOS logic process, non-volatile memory devices are typically made using charge storage in a floating gate electrode. In general, it takes a lower voltage to inject hot electrons from silicon into a floating gate electrode than to inject electrons from silicon into a floating gate electrode by Fowler-Nordheim tunneling. As a result, for high-speed and low-voltage operation, hot electron injection is typically used.
Floating gate Field Effect Transistors (FETs) including a control gate are well known. A floating gate electrode differs from a control gate electrode in that it has no direct electrical connection to any external component and is surrounded by isolation on all sides. In a typical floating gate FET including a control gate, the control gate is positioned on top of the floating gate. The presence of a control gate electrode enables an FET device to function as a regular FET, while a floating gate electrode collects and stores injected electrons or holes. The floating gate electrode provides a method for changing the threshold voltage needed to pass a charge from the source region of the FET to the drain region thereof. The presence of the control gate electrode adds control to the injection of charges into and out of the floating gate region of the FET, thus enabling the FET device to function as an electrically programmable or reprogrammable memory device depending upon other factors as explained below.
Source-side injection flash cells or split gate flash cells are commonly used as embedded flash memories. In a split gate cell, the floating gate overlies only a portion of the channel and the control gate electrode overlies both the floating gate electrode and the remainder of the channel. In other words, there are two transistors in series between a source and a drain. One relatively popular flash cell employs oxidized polysilicon to create sharp points in the polysilicon in order to enhance the electric field. This in turn allows erasure at lower voltages and provides for thicker dielectric layers between the floating gate electrode and the control gate electrode. The LOCalized Oxidation of Silicon (LOCOS) process is commonly used for fabricating such cells to form an insulator cap over the polysilicon of the floating gate electrode. The LOCOS process creates sharp points on the floating gate electrode, resulting in a bird's beak structure.
Nevertheless, the existing flash memory cells exhibit two major shortcomings which are high programming voltage required and non-planar cell topography due to the presence of the floating gate electrode.
In a floating gate device, electrons are injected into the floating gate electrode, either by hot electron injection or by electron tunneling (Fowler-Nordheim or F-N tunneling). In the case of hot electron injection, it is well-known that it is much more efficient to use avalanche hot electron injection using a p-channel FET device than to use channel hot electron injection using an n-channel FET device. A paper by Hsu et al. entitled "A High-Speed Low-Power P-Channel Flash EEPROM Using Silicon-Rich Oxide as Tunneling Dielectric," 1992 Int. Conf. Solid-State Devices and Materials, Extended Abstract, pp. 140-142 (1992) includes experimental evidence that it is desirable to use both a p-channel floating-gate FET as the memory element and avalanche hot electron injection as the programming mechanism.
For embedded applications, it is desirable to use an access or select transistor connected in series with the memory element to form the non-volatile memory cell. While adding a select transistor adds area to the memory cell, the use of a select transistor avoids many issues of operation of a true single-device memory cell with no access transistor. For example, such an access transistor guarantees that there is no over-erase problem, and avoids disturbing the non-selected cells.
For the select transistor, it is desirable to use an n-channel FET, instead of a p-channel FET, because an n-channel FET typically has twice the performance as a p-channel FET due to higher electron mobility. In other words, it is desirable to have a CMOS non-volatile memory device where the n-channel FET is used as an access transistor and the floating-gate p-channel FET is used as the memory element.
U.S. Pat. No. 7,091,075 B2 of Chaudhry entitled "Fabrication of an EEPROM Device with SiGe Source/Drain Regions" shows a non-volatile memory device which employs an nFET and a pFET, but it is built using bulk CMOS devices, not SOI CMOS. The pFET is used as select device while the nFET gate electrode is floating and is used as memory device. The present invention teaches using a pFET, with its gate electrode floating, as the memory device, while the nFET is used as select device. A problem with such a device are first that a pFET select device has only about half the performance of a nFET select device and second that a floating-gate nFET used as memory device has much higher power dissipation compared with a floating-gate pFET employed as a memory device.
U.S. Pat. No. 6,841,447 of Logie entitled "EEPROM Device having an Isolation-Bounded Tunnel Capacitor and Fabrication Process" describes a memory element built using bulk CMOS devices, not an SOI CMOS consisting of both an nFET and a pFET, with the floating gate electrode of the pFET and the floating gate electrode of the nFET are connected together electrically. Also there is a control gate electrode "on top" of the connected floating gate electrode. A problem with such a device is that the resulting memory element, consisting of an nFET and a pFET, is significantly larger than the present invention where only the floating-gate pFET is used as memory element. In contrast to Logie, according to the present invention, only the pFET, with its gate electrode floating, is used as memory element.
U.S. Pat. No. 5,016,217 of Brahmbhatt entitled "Logic Cell Array Using CMOS EPROM Cells Having Reduced Chip Surface Area" describes an Electrically Programmable Read Only Memory (EPROM) memory cell including a serially connected Complementary Metal Oxide Silicon (CMOS) transistor pair with common floating gate electrodes and common control gate electrodes. A third n-type floating gate FET is used to program the memory cell. The floating and control gates of the third transistor are connected to the common floating and control gates, respectively, of the CMOS transistor pair. A tri-state memory cell can be provided by connecting the source of the p-channel transistor of the CMOS pair to the common control gates. An EPROM cell is described including the pFET and the nFETs in the cell all of which have a floating gate. Those floating gates are all electrically connected together. Each FET has a control gate above the floating gate. According to the present invention, the nFET does not have a floating gate, while the pFET has a floating gate but without a control gate. A problem with such a device is that a very large area is taken up by the floating-gate memory element which covers all three transistors. In addition, Brahmbhatt is built using bulk CMOS devices which have an additional problem that the pFET is built using an n-well and the nFETs are built using a p-well. Since the well regions are larger than the actual pFET and nFET devices themselves, the resulting area taken up to build the Brahmbhatt memory device is significantly larger than the area of a memory device built in accordance with the present invention.
U.S. Pat. No. 5,886,376 of Acovic et al entitled "EEPROM Having Coplanar On-Insulator FET and Control Gate" describes an electrically erasable programmable read-only memory (EEPROM) which includes an FET and a control gate spaced apart on a first insulating layer. A second insulating layer is formed over the FET and the control gate and a common floating gate on the second insulating layer over the channel of the FET and the control gate, the floating gate thus also forms the gate electrode of the FET. The EEPROM devices may be interconnected in a memory array and a plurality of memory arrays may be stacked on upon another. In contrast, the present invention overcomes the problem of using a non-standard Silicon-On-Insulator (SOI) CMOS process to make EEPROM arrays with high areal density.
U.S. Pat. No. 6,215,689 B1 of Chorr entitled "Architecture, Circuitry and Method for Configuring Volatile and/or Non-Volatile Memory for Programmable Logic Applications" describes a memory device, states as follows: "Architecture, circuitry, and methods are provided for operating a high speed, volatile programmable logic integrated circuit using back-up non-volatile memory cells configured on an integrated circuit separate from the programmable logic integrated circuit. The lower density non-volatile memory cells can be formed on an integrated circuit using fabrication steps similar to those used to form, e.g., EEPROM devices or, more specifically, flash EEPROM devices. The programmable logic integrated circuit includes high density, volatile memory cells integrated with high speed, low density configurable CMOS-based logic. By using two separate processing technologies on two separate and distinct monolithic substrates, and interconnecting the separate integrated circuits on a singular monolithic substrate, the advantages of non-volatility can be combined with a high speed programmable circuit. The pins extending from the programmable logic device can be mounted in various ways to corresponding receptors on a printed circuit board. The architecture, circuitry, and method thereby present a packaged device which inherently has the same characteristics as a single integrated circuit, yet is actually two integrated circuits having the benefits of non-volatility as well as the benefits of higher speed, higher density volatile logic blocks within a programmable logic device or complex programmable logic device." In accordance with the present invention, the memory element is fully compatible with CMOS logic process, and both memory and logic elements are made on the same silicon chip. In Chorr memory elements and logic elements are made on different silicon chips by different process flows, with the problem that the device lacks the desirable attribute of integrating all the desired logic circuits and memory functions on a single chip.
U.S. Pat. No. 6,207,991 B1 of Rahim "Integrated Non-Volatile and CMOS Memories Having Substantially the Same Thickness Gates and Methods of Forming the Same" describes a method of forming non-volatile memory (e.g. an EEPROM device) and a bulk CMOS device (e.g. a RAM), not a SOI CMOS, on a single die or chip, and a structure formed by the method. In one embodiment, the control gate of the storage transistor as well as the isolation gate of the isolation transistor may be formed during the same manufacturing process step, and thus may be formed of the same gate polysilicon material and may have similar thickness. The memory device in the Rahim patent is an nFET device. A problem with such an nFET memory device is that it requires more power dissipation to program a floating-gate nFET than a floating-gate pFET. In the present invention, the memory device is a pFET device.
U.S. Pat. No. 6,498,371 of Krishnan et al. entitled "Body-Tied-To-Body SOI CMOS Inverter Circuit" describes an SOI CMOS inverter circuit in which the drain of each of an n-FET and a P-FET are electrically coupled to form an output of the inverter circuit by a silicide layer in combination with a body region formed in the SOI layer ties. At the same time, however, the body regions remain floating electrically so that the benefits of SOI are maintained.
To reduce cell area in bulk CMOS implementations, a p-FET is usually used for an access transistor instead of an n-FET. Such all p-FET bulk CMOS implementations are described in both U.S. Pat. No. 6,678,190 of Yang entitled "Single Poly Embedded EPROM" and U.S. Pat. No. 6,711,064 of Hsu entitled "Single-Poly EPROM". U.S. Pat. No. 6,678,190 of Yang describes an erasable programmable read only memory comprising two serially connected P-type metal-oxide semiconductor (MOS) transistors wherein the control gate is omitted in the structure for layout as the bias is not necessary to apply to the floating gate during the programming mode. U.S. Pat. No. 6,711,064 of Hsu describes a single-poly EEPROM which includes a first PMOS transistor that is serially connected to a second PMOS transistor. The first and second PMOS transistors are both formed on an N-well of a P-type substrate. The first PMOS transistor includes a floating gate, a first P+ doped drain region, and a first P+ doped source region. The second PMOS transistor includes a gate and second P+ doped source region. The first P+ doped source region of the first PMOS transistor serves as a drain of the second PMOS transistor. For erasing the single-poly EEPROM, an erase gate which extends to the floating gate is provided in the P-type substrate. A problem with such a device is that a pFET access transistor has only about half the performance of an nFET access transistor.
B Commonly assigned U.S. Pat. No. 7,244,976 of Cai et al. entitled "EEPROM Device with Substrate Hot-Electron Injector for Low-Power Programming" describes a low programming power, high speed EEPROM device adapted for large scale integration. The device comprises a body, a source, and a drain, plus it has means for injecting a programming current into the body. The hot carriers from the body enter the floating gate with much high efficiency. The drain current of the device, which is built on an insulator, with a bottom common plate, and a top side body, is controlled by the body bias. The device is adapted for SOI and thin film technologies.
FIG. 1A is a schematic diagram of a cross section of a prior art CMOS inverter 10 comprising an SOI nFET 11 and an SOI pFET 13. FIG. 1B is an electrical schematic diagram of the device of FIG. 1A. The inverter 10 is formed on a substrate 12 preferably composed of silicon, with a Buried Oxide (BOX) layer 14 formed on the top surface thereof. A left isolation oxide region 15L is formed over the BOX layer 14 on the left of the inverter 10; and a right isolation oxide region 15R is formed over the BOX layer 14 on the right of the inverter 10. An SOI layer composed of doped regions 16, 17, 18, 19, 20 and 21 is formed over the BOX layer 14 between left isolation oxide region 15L and the right isolation oxide region 15R. The nFET II is composed of an n+ doped source region 16, a p doped channel region 17 and an n+ drain region 18, which are formed on the top surface of the BOX layer 14 adjacent to the left isolation oxide region 15L. The pFET 13 is composed of p+ doped drain region 19, an n doped channel region 20 and a p+ source region 21 which are formed on the top surface of on the BOX layer 14 between the n+ drain region 18 and the right isolation oxide region 15R.
The nFET 11 includes a thin gate dielectric (silicon dioxide or other electrical insulating material) layer 23 formed over the p doped channel region 17 of the nFET 11 and a first gate electrode G1, which is electrically conductive, located above the thin gate dielectric layer 23.
The pFET 13 includes a second, thin gate dielectric (silicon dioxide or other electrical insulating material) layer 25, formed over the n doped channel region 20 of the pFET 13, and a second gate electrode G2, which is also electrically conductive, located above the second gate dielectric layer 25. The first and second gate dielectric layers 23 and 25 have thicknesses which are thin, as stated above, and are preferably substantially equal.
A first silicided contact 22 (S) is formed on the top surface of the source region 16 of the nFET 11. A second silicided contact 24, which is formed on the combined top surfaces of both the drain region 18 of the nFET 11 and the drain region 19 of the pFET short circuits the drains regions 18 and 19 together. A third silicided contact 26(S) is formed on the top surface of the source region 21 of the pFET 13. The first silicided contact region 22(S) and the second silicided contact region 24 are spaced away from the first gate electrode G1, and the second and third silicided contact regions 24 and 26(S) are spaced away from the second gate electrode G2.
Referring to both FIGS. 1A and 1B, the first silicided contact 22 connects reference potential Vss, i.e. ground voltage, which equals zero Volts, to the source region 16 of the nFET 11. The first gate electrode G1 is connected by line 28A to an input terminal VIN and to line 28B which connects to the second gate electrode G2, so that the first gate electrode G1 is electrically connected to the second gate electrode G2, with both of them being at the input potential VIN. The second silicided contact 24 is connected to an output terminal VOUT. The third silicided contact 26(S) is connected to a power supply terminal Vdd. Referring to FIG. 1C, the input and output voltages of the inverter 10 are related so that when VIN is in a logic state of "0" or has a value substantially equal to zero, VOUT is in a logic state of "1" or has a value substantially equal to Vdd, and when VIN is in a logic state of "1" or has a value substantially equal to Vdd, VOUT is in a logic state of "0" or has a value substantially equal to zero. These relationships are indicated in Table I below, as will be well understood by those skilled in the art.
TABLE IVINVOUT"0" or zero"1" or Vdd"1" or Vdd"0" or zero
FIG. 1D is a schematic diagram of a cross section of a prior art MOS FET EPROM device 30 comprising a bulk pFET 31 and another bulk pFET 33, without any n-FET devices, formed on an N-well 39. The N-well 39 is centered between the right edge of a left isolation oxide region 35L and the left edge of a right isolation oxide region 35R. The pFET 31, which is formed adjacent to the left isolation oxide region 35L, is composed of an p+ doped source region 32(S), an n doped channel region CH1 and the left half of a shared, p+ doped region 37. The pFET 33 is composed of the right hand half of the shared, p+ doped region 37, an n doped channel region CH2 and a p+ drain region 36 formed between the pFET 31 and the right isolation oxide region 35R. The shared, p+ region 37 is the source for the pFET device 33. For a pFET, the region with higher voltage is the source and the region with the lower voltage is the drain, visa versa for an nFET. For two pFETs in series, as in FIG. 1D, the highest voltage (Vdd) is applied to region 32(S), or the source of pFET 31, and the region 37 is the drain of pFET device 31 as well as the source of the pFET device 33. The p+ drain region 36 is the drain of pFET device 33.
As in FIG. 1A, the pFET 31 includes a thin gate dielectric (gate oxide) layer 23 formed over the first channel region CH1 of the pFET 31 and a third gate electrode G3, which is electrically conductive, located above the thin gate dielectric layer 23.
The pFET 33 includes a first thick gate dielectric (e.g. silicon oxide) layer 25F, formed over the n doped channel region CH2 of the pFET 33, and a first floating gate electrode FG1, which is also electrically conductive, located above the first thick gate dielectric layer 25F. The gate dielectric layer 23 and the first thick gate dielectric layer 25F have substantially different thicknesses with the first thick gate dielectric layer 25F being substantially thicker than gate dielectric layer 23, since the thick gate dielectric must be sufficiently thick to prevent leakage of charge stored on the floating gate FG1, as stated by the following references. U.S. Pat. No. 6,992,926 of Iwase et al. entitled "Driver Circuit for Semiconductor Storage Device and Portable Electronic Apparatus" states "For prevention of leakage of holding charges, the thickness of an insulating film isolating the floating gate from the channel region or the well region cannot be reduced to about 7 nm or less." In addition, an article by Prinz et al entitled "Nonvolatile memories for 90 nm SoC and beyond" stated as follows: "To maintain high reliability for safety-critical applications, the insulators surrounding the floating gate must be thicker than 100 angstroms if error correction is not employed. This is due to the fact that a single point defect in an insulator is sufficient to create a leakage path through which the entire floating gate charge can leak out.", EE-Times, http://www.eetimes.com/story/OEG20030317S0057 (2003)

CMOS EPROM and EEPROM devices and programmable CMOS inverters

International Business Machines Corporation