A process for catalytic conversion of hydrocarbon feedstock to produce isobutane and isoparaffin-enriched gasoline which comprises two different reactions, the preheated feedstock is contacted with hot regenerated catalyst in the lower part of a reactor with the result that catalytic cracking reaction takes place, and the mixture of vapors and the coke deposited catalyst are up-flowed and enter into a suitable reaction environment with the result that isomerization and hydrogen transfer reaction take place. The produced LPG has an isobutane content of about 20 wt % to about 40 wt % and the produced gasoline contains isoparaffin content of about 30 wt % to about 45 wt % and olefin content of less than 30 wt %. RON and MON of the gasoline are 90xcx9c93 and 80xcx9c84 respectively.

This invention relates to a process for catalytic conversion of hydrocarbon feedstock in the absence of added hydrogen. More particularly, the present invention relates to a catalytic conversion process for producing isobutane and isoparaffin-enriched gasoline.
The mixture of isoparaffins possessing high octane number, low octane sensitivity, appropriate volatility and clean burning is an ideal blending components for aviation gasoline and motor gasoline. The mixture of isoparaffins can be obtained by propylene polymerization or alkylation reaction of isobutane and olefins.
The conventional fluidized catalytic cracking (FCC) technology is used for producing gasoline with a yield of up to 50 wt %. In the 1980s, the phase down of leaded gasoline forced the catalytic cracking technology to go forward to the production of high octane gasoline. The changing market demands have resulted in a great change in technology and catalyst types. The advance in technological development is to increase reaction temperature, shorten reaction time, intensify reaction severity, suppress hydrogen transfer reaction and overcracking reaction and improve the contacting efficiency between feedstock and hot catalyst at the bottom of a riser reactor. In catalyst development, the catalysts containing USY zeolite supported on an inert or active matrix or containing different typed zeolites have been put into commercial use.
Though FCC technology has been advanced to meet octane blending requirement, whether it is by means of changing in process parameters or using novel catalysts for increasing gasoline octane number, it results in an increase in olefin content of FCC gasoline. Apparently, there is a great difference between the olefin contents of about 35 wt %xcx9c65 wt % in FCC gasoline and that required for reformulated gasoline (RFG). FCC liquid petroleum gas (LPG) has an olefin content of up to 70 wt %, in which butylenes is several times as much as the yield of isobutane, so it is not fit to be used as feedstock for alkylation.
U.S. Pat. No. 5,154,818 discloses a method for the fluidized catalytic cracking of plural hydrocarbon feedstocks in a riser reactor to produce more gasoline of high octane number. The process generally comprises two reaction zones. A relatively light hydrocarbon feedstock contacts with spent catalyst in a first reaction zone located in the bottom of a conventional riser where aromatization and oligomerization take place. All of the first reaction zone effluent, the regenerated catalyst and heavy hydrocarbon feedstock are introduced into the second reaction zone where heavy hydrocarbon feedstock is cracked to desired reaction products. The reaction products and spent catalyst then pass through disengager for removal of entrained catalyst before the hydrocarbon vapors pass into a separation system. Spent catalyst passes into stripper and is divided into two parts, one is introduced into regenerator for burning off coke, the other part is recycled to the first reaction zone.
U.S. Pat. No. 4,090,948 discloses a catalytic cracking process for producing the desired conversion of hydrocarbon feedstock of inferior quality (having higher contents of basic nitrogen and carbon residue) to obtain higher yields of the desired products in a riser reactor. The process generally comprises contacting the hydrocarbon feedstock containing the highly reactive nitrogen and carbon residue with a recycled spent catalyst in the first reaction zone where the highly reactive nitrogen and carbon residue will deposit on the spent catalyst and then contacting the resultant mixture with freshly regenerated catalyst in the second reaction zone. The reaction products and spent catalyst then pass through disengager for removal of entrained catalyst before the hydrocarbon vapors pass into a separation system. Spent catalyst passes into stripper and is divided into two parts, one is introduced into regenerator for burning off coke and then returned to the second reaction zone, and the other part is recycled without regeneration to the first reaction zone.
Though the above two prior art processes have divided an iso-diameter riser reactor into two reaction zones, the reactions take place at lower temperature in the first reaction zone and the reactions take place at higher temperature in the second reaction zone. In addition, the processes utilize a conventional riser reactor without flexibility for adjusting operating conditions. This arrangement is subject to significant disadvantages to carry on catalytic cracking reaction and selective hydrogen transfer at the same time for producing LPG with higher yield of isobutane and isoparaffin enriched gasoline.
An object of the present invention is to provide a catalytic conversion process for producing isobutane and isoparaffin-enriched gasoline to meet the requirement for blending components of the RFG, i.e., limiting the olefin content on the premise of maintaining higher gasoline octane number.
The process provided by the present invention is to contact the preheated hydrocarbon feedstock with hot regenerated catalyst in the lower part of a reactor with the result that hydrocarbon cracking reaction takes place at higher reaction temperature and shorter reaction time, and then the resultant mixture is up-flowed and enters into a suitable reaction environment with the result that isomerization and hydrogen transfer reaction take place at lower reaction temperature and longer reaction time. The reaction products and spent catalyst that pass through disengager for removal of entrained catalyst. The reaction products flow into subsequent separation system. Spent catalyst is stripped with steam, and then flow into the regenerator for regeneration, and thereafter the hot regenerated catalyst is recycled to the lower part of the reactor.
The process provided by the present invention employs a reactor to carry on two different reactions under different operating conditions, said reactor is preferably selected from the group consisting of an iso-diameter riser, an iso-linear velocity riser, a multi-cascade riser, a fluidized bed or a combination reactor of an iso-diameter riser and a fluidized bed.
The applicants have found that the olefins produced by catalytic cracking reaction can be selectively converted into isoparaffins and aromatics or isoparaffins and coke under specific reaction conditions and with specific catalysts.
The present invention is practiced by different embodiments. In embodiment one, the invention is a process comprising: the preheated hydrocarbon feedstock is atomized with injection steam and charged into the bottom of a conventional iso-diameter riser, and then mixed with hot regenerated catalyst with the result that feedstock is vaporized and cracked. The product vapors and the coke deposited catalyst are up-flowed and are mixed with cooled regenerated catalyst with the result that isomerization and hydrogen transfer reaction take place. The reaction vapors and catalyst flow into disengager where entrained catalyst is separated and dropped into the catalyst stripper. The reaction vapors are separated into products in subsequent separation system. Spent catalyst is stripped and introduced into regenerator for regeneration. Regenerated catalyst is divided into two parts, one is recycled into the prelift zone of the riser, and the other part is cooled in catalyst cooler and then recycled into the second reaction zone.
In embodiment two, this invention is a process comprising: the preheated hydrocarbon feedstock is atomized with injection steam and charged into the bottom of a convention iso-diameter riser, and then mixed with hot regenerated catalyst with the result that the feedstock is vaporized and cracked. The product vapors and the coke deposited catalyst are up-flowed and are mixed with cooled semi-regenerated catalyst with the result that isomerization and hydrogen transfer reaction take place. The reaction vapors and catalyst flow into disengager where entrained catalyst is separated and dropped into the catalyst stripper. The reaction vapors are separated into products in subsequent separation system. Spent catalyst is stripped and introduced into the primary regenerator for regeneration. Semi-regenerated catalyst is divided into two parts, one flows into the secondary regenerator for regeneration, and then is recycled into the prelift zone of the riser, and the other part is cooled in catalyst cooler and then recycled into the second reaction zone.
In embodiment three, this invention is a process comprising: the preheated hydrocarbon feedstock is atomized with injection steam and charged into the bottom of the riser in a combination reactor of an iso-diameter riser and a fluidized bed, and then mixed with hot regenerated catalyst with the result that the feedstock is vaporized and cracked. The product vapors and the coke deposited catalyst in the riser flow upward and are mixed with cooled regenerated catalyst with the result that isomerization and hydrogen transfer reaction take place in the fluidized bed. The reaction vapors and catalyst flow into disengager where entrained catalyst is separated and dropped into the catalyst stripper. The reaction vapors are separated into products in subsequent separation system. Spent catalyst is stripped and introduced into regenerator for regeneration. Regenerated catalyst is divided into two parts, one is recycled into the prelift zone of the riser, and the other part is cooled in catalyst cooler and then recycled into the fluidized bed.
In a more preferred embodiment of this invention, this invention comprises that the preheated hydrocarbon feedstock is atomized with injection steam and charged into the bottom of the first reaction zone in a multi-cascade riser, and then mixed with hot regenerated large particle size distribution catalyst containing USY zeolite with the result that feedstock is vaporized and cracked, providing the lifting force to carry the product vapors and the coke deposited catalyst in the first reaction zone into the second reaction zone where the effluents are mixed with the cooled regenerated small particle size distribution catalyst containing rare-earth Y zeolite with the result that isomerization and hydrogen transfer reaction take place. The reaction vapors and catalyst flow into disengager where entrained catalyst is separated and dropped into the catalyst stripper. The reaction vapors are separated into products in subsequent separation system. Spent catalyst is stripped and introduced into regenerator for regeneration. Regenerated catalyst is divided into the large particle size distribution catalyst and the small particle size distribution catalyst, the large particle size distribution catalyst is recycled into the prelift zone of the riser, and the small particle size distribution catalyst is cooled in catalyst cooler and then recycled into the second reaction zone.
The above embodiments are not meant to limit the present invention to the details disclosed herein.

Catalytic conversion process for producing isobutane and isoparaffin-enriched gasoline

Research Institute of Petroleum Processing


This invention comprises a photographic element comprising at least one silver halide emulsion layer in which the silver halide is sensitized with a compound of the formula X--H, wherein X is an electron donor moiety to which a base, B.sup.-, is covalently linked and H is a leaving hydrogen atom, and wherein:. 1) X--H has an oxidation potential between 0 and about 1.4 V; and PA1 2) the oxidized form of X--H undergoes deprotonation reaction with the base B.sup.-, to give the radical X.sup..cndot. and the protonated base B-H.. In a preferred embodiment of the invention, the radical X.cndot. has an oxidation potential <-0.7V.

A variety of techniques have been used to improve the light-sensitivity of photographic silver halide materials.
Chemical sensitizing agents have been used to enhance the intrinsic sensitivity of silver halide. Conventional chemical sensitizing agents include various sulfur, gold, and group VIII metal compounds.
Spectral sensitizing agents, such as cyanine and other polymethine dyes, have been used alone, or in combination, to impart spectral sensitivity to emulsions in specific wavelength regions. These sensitizing dyes function by absorbing long wavelength light that is essentially unabsorbed by the silver halide emulsion and using the energy of that light to cause latent image formation in the silver halide.
Many attempts have been made to further increase the spectral sensitivity of silver halide materials. One method is to increase the amount of light captured by the spectral sensitizing agent by increasing the amount of spectral sensitizing agent added to the emulsion. However, a pronounced decrease in photographic sensitivity is obtained if more than an optimum amount of dye is added to the emulsion. This phenomenon is known as dye desensitization and involves sensitivity loss in both the spectral region wherein the sensitizing dye absorbs light, and in the light sensitive region intrinsic to silver halide. Dye desensitization has been described in The Theory of the Photographic Process, Fourth Edition, T. H. James, Editor, pages 265-266, (Macmillan, 1977).
It is also known that the spectral sensitivity found for certain sensitizing dyes can be dramatically enhanced by the combination with a second, usually colorless organic compound that itself displays no spectral sensitization effect. This is known as the supersensitizing effect.
Examples of compounds which are conventionally known to enhance spectral sensitivity include sulfonic acid derivatives described in U.S. Pat. Nos. 2,937,089 and 3,706,567, triazine compounds described in U.S. Pat. Nos. 2,875,058 and 3,695,888, mercapto compounds described in U.S. Pat. No. 3,457,078, thiourea compounds described in U.S. Pat. No. 3,458,318, pyrimidine derivatives described in U.S. Pat. No. 3,615,632, aminothiatriazoles as described in U.S. Pat. No. 5,306,612 and hydrazines as described in U.S. Pat. Nos. 2,419,975, 5,459,052 and 4,971,890 and European Patent Application No. 554,856 A1. The sensitivity increases obtained with these compounds generally are small, and many of these compounds have the disadvantage that they have the undesirable effect of deteriorating the stability of the emulsion or increasing fog.
Various electron donating compounds have also been used to improve spectral sensitivity of silver halide materials. U.S. Pat. No. 3,695,588 discloses that the electron donor ascorbic acid can be used in combination with a specific tricarbocyanine dye to enhance sensitivity in the infrared region. The use of ascorbic acid to give spectral sensitivity improvements when used in combination with specific cyanine and merocyanine dyes is also described in U.S. Pat. No. 3,809,561, British Patent No. 1,255,084, and British Patent No. 1,064,193. U.S. Pat. No. 4,897,343 discloses an improvement that decreases dye desensitization by the use of the combination of ascorbic acid, a metal sulfite compound, and a spectral sensitizing dye.
Electron donating compounds that are covalently attached to a sensitizing dye or a silver-halide adsorptive group have also been used as supersensitizing agents. U.S. Pat. Nos. 5,436,121 and 5,478,719 disclose sensitivity improvements with the use of compounds containing electron-donating styryl bases attached to monomethine dyes. Spectral sensitivity improvements are also described in U.S. Pat. No. 4,607,006 for compounds containing an electron-donating group derived from a phenothiazine, phenoxazine, carbazole, dibenzophenothiazine, ferrocene, tris(2,2'-bipyridyl)ruthenium, or a triarylamine skeleton which are connected to a silver halide adsorptive group. However, these latter compounds generally have no silver halide sensitizing effect of their own and provide only minus-blue sensitivity improvements when used in combination with a sensitizing dye.

Silver halide light sensitive emulsion layer having enhanced photographic sensitivity


The present invention provides a drug delivery system containing a pharmaceutically active core and a coating of the core. The coating is comprised of a an emulsifier and a wax. The coating provides rapid dissolution and enhanced long-term stability for the pharmaceutically active ingredient.

Numerous drugs are known for their unpleasant taste and the prior art has disclosed products to mask these drugs from unpleasant tastes. To be effective coatings must not merely mask the taste by overcoming the unpleasant taste but also delay the hydration of the drug until it passes the mouth and taste buds.
U.S. Pat. No. 4,797,288 discloses a drug delivery system which may be chewed or swallowed that contains a hydrophobic matrix of an emulsifier, an edible material having a melting point below 100.degree. C. selected from a fatty acid, natural waxes, synthetic waxes and mixtures thereof. The matrix is coated with a coating consisting of fatty acids and wax combination. The coat level is 200% to 400% by weight resulting in a low drug potency. Due to the high coating levels employed and materials employed in the matrix it is expected that the drug delivery rate is retarded.
European Patent 455 391 discloses granules of polyglycerol esters and a pharmaceutically active material made in a fluidized bed. The fluidized bed is heated and the material is entrained in the heated fluidized bed until the polyglycerol esters are melted and the particles are agglomerated.
U.S. Pat. No. 5,399,357 discloses a stable controlled release pharmaceutically acceptable matrix preparation consisting of a fatty acid ester of polyglycerol and microcrystalline waxes. The drug dissolution rate is retarded resulting in prolonged release not suitable for immediate drug action in the body. The system claimed is a matrix not a coating.
Although these prior disclosures provide taste masked compounds, the described systems do not provide a dissolution rate that is suitable for a pharmaceutical product where the drug is immediately released and available for drug absorption. Those with skill in the art will appreciate that the therapeutic effect will thus be delayed, see for example, "Dissolution, Bioavailability and Bioequivalence" by H. M. Abdou, Mack Publishing Company, 1989.
Additionally, the above identified disclosures do not provide any data to show that the systems are physically stable. If the systems are not stable, the delivery of the active pharmaceutical ingredient can vary over time based on environmental conditions and the length of time the pharmaceuticals have been in storage.
Therefore alternative formulations which provide uniform, stable dissolution rates during storage in various environmental conditions but which also provide rapid dissolution once ingested is highly desirable.


One embodiment of the invention relates to a method for accessing a memory cell. In this method, at least one bit of the memory cell is erased. After erasing the at least one bit, a soft program operation is performed to bias the memory cell thereby improving the reliability of data stored in the memory cell.

Many different types of memory exist to store data for computers and other digital devices. Flash memory is one type of memory that has become popular because it combines the high density and low cost of EPROM with the electrical erasability of EEPROM. Flash memory can be rewritten and can hold its contents without power, and thus is nonvolatile. It is used in many portable electronic products, such as cell phones, portable computers, voice recorders, etc., as well as in many larger electronic systems, such as cars, planes, industrial control systems, etc.
FIG. 1 shows one example of a dual-bit flash memory cell 100, which is a memory cell is essentially split into two identical (mirrored) parts, each of which is formulated for storing one of two independent bits. Thus, one bit of data can be independently stored in one of two storage regions 102, 104. The dual bit memory cell, like a traditional single bit flash memory cell, has a wordline (WL) 106 associated with a source 108 and a drain 110. Like a traditional single bit flash memory cell, a channel region 112 may exist under the wordline between the source and drain.
A stacked gate structure 114, which may include a multi-level dielectric layer 116 and the wordline 106, is formed over the semiconductor substrate or p-well 118. The multi-level dielectric layer 116 can generally be composed of three separate layers: a first insulating layer 120, a charge-trapping layer 122, and a second insulating layer 124. The wordline 106 is formed over the multi-layer dielectric layer 116.
In FIGS. 2A-2D, a prior art method 200 for performing a memory operation on the dual-bit memory cell 100 is described with reference to a flow diagram (FIG. 2A) and schematic representations (FIGS. 2B-2D). The illustrated flow diagram (FIG. 2A) shows general functional steps, while the schematic representations (FIG. 2B-2D) show various bias conditions applied on a dual-bit cell and movement of charged carriers (i.e., holes p+, and/or electrons n−) at various blocks of the method 200.
As shown in FIG. 2A, the method 200 proceeds differently depending on whether a user is programming the memory cell or erasing the memory cell. If the operation is a program operation ("PROGRAM" at 202), the method 200 proceeds to block 204 wherein one bit of the memory cell is programmed. Conversely, if the operation is an erase operation ("ERASE" at 202), the method proceeds to block 206 wherein one bit of the memory cell is erased.
After the right bit of the cell is programmed (FIG. 2B, 204A) and/or the left of the cell is programmed (FIG. 2C, 204B), a user may want to erase either bit of data in the cell. Referring now to FIG. 2D, one can see an erase operation 206 in accordance with the prior art, wherein the right bit of the cell is erased. A relatively high voltage (6V) is applied to the drain, and the wordline WL is held at a negative voltage (−6V), while the source is allowed to float. Under these conditions, a strong electric field is developed across the multi-layer dielectric 116 between the wordline and the drain. The negatively charged electrons that are trapped in the charge trapping layer 122 are attracted to the positive voltage on the drain, while positively charged holes flow from the substrate or p-well 118 into the charge trapping layer 122, both by way of Fowler-Nordheim tunneling through the tunnel oxide 120. As the electrons are removed from the charge trapping layer and holes flow into the charge trapping layer, the cell is erased.
One shortcoming of the prior art method 200 is that hot-carriers (e.g., accelerated carriers) are difficult to precisely control. Thus, for example, while the cell is erased, an excess number of holes may be injected into the charge trapping layer 122 or an excess number of electrons may be removed from the charge trapping layer. In either case, the voltage threshold of the cell may differ from an expected threshold value, causing the data stored in the cell to be less reliable. Therefore, during a subsequent read operation, the cell may provide a different current from the drain to source then expected. Because the current level may be indicative as to the data value stored in the cell, the cell will return unreliable data.
Therefore, a need has arisen to provide systems and methods relating to memory devices that cure some deficiencies of the prior art.

Abstract: Other methods and systems are also disclosed.


The present invention is directed to a system for and a method of automatically generating personal homepages accessible through the Internet. The method includes entering data indicative of the identity of a salesperson, harvesting personal data associated with the identified salesperson from a human resource database, and automatically generating a personal homepage by populating the template with the personal data. Preferably, the homepage is automatically disabled when data from the human resource database indicates that the person is no longer employed with the organization.

As electronic commerce and the information economy become more popular, it is important that all organizations, and particularly large organizations, have a presence on the Internet. Nowhere is this more important than in an organization's sales and marketing efforts. While marketing is important to all companies, it is particularly important to companies and organizations where the human channels are the main sales vehicle, such as those offering financial services, such as stocks, bonds, investments, insurance policies, annuities and the like.
It is important for these companies to maintain the personal relationship between the members of their sales force and their customers while taking advantage of the Internet. In addition to resolving channel cannibalization issues, many organizations are fighting the inertia of a sales force that may be uninformed or fearful of the Internet's impact on their job functions. Moreover, conventional methods for creating web pages are labor intensive and require specialized skill sets. These companies need a way to quickly provide an Internet presence for the members of the sales force to maintain the human personal contact to their current customers who may be increasingly embracing doing business in an impersonal manner over the Internet. These companies need a vehicle to quickly provide their sales force with a relevant presence on the Internet that complements, rather than competes, with the companies other Internet marketing initiatives.

Automatic generation of personal homepages for a sales force

Abstract: The system includes an application server linked to a database of personal data of the sales force members. The application server includes a homepage template. Personal data is available in the database to be communicated to the application server to automatically populate the homepage template when requested, thereby generating a personal homepage for the member for viewing on an Internet.


The present invention is an improvement upon the known method of anionically polymerizing monomers by contacting the monomers with an anionic polymerization initiator which is an organo-substituted alkali metal compound. The improvement comprises decreasing the viscosity of the polymer cement by adding at least 0.01 equivalent of a metal alkyl compound per equivalent of alkali metal initiator if the metal alkyl is added before or at the beginning of polymerization. If the metal alkyl is added during the polymerization or after but before the living polymer is terminated, then at least 0.01 equivalent of the metal alkyl compound per equivalent of living polymer chain ends is should be used. The alkyl groups of the metal alkyl are chosen such that they do not exchange with the organo substituents of the alkali metal, which can be the living polymer chain ends or the organo substituents of the initiator. To avoid this undesired exchange reaction, the alkyl groups of the metal alkyl compound are selected to be more basic and/or less bulky or both than the organo substituents of the alkali metal compound.

This invention relates to the manufacture of polymers by anionic polymerization of monomers, especially conjugated dienes and/or vinyl aromatic hydrocarbons, in a hydrocarbon solvent. More particularly, this invention relates to an improvement in such a process whereby the throughput of the manufacturing system is increased by reducing the viscosity of the polymer cement (the solution of the anionic polymer in the hydrocarbon solvent).
Anionic polymers, including polymers of conjugated dienes and/or vinyl aromatic hydrocarbons, have been produced by numerous methods. However, anionic polymerization of such or other monomers in the presence of an anionic polymerization initiator is the most widely used commercial process. The polymerization is carried out in an inert solvent such as hexane, cyclohexane, or toluene and the polymerization initiator is commonly an organo alkali metal compound, especially alkyl lithium compounds. The solvent used is almost always a non-polar hydrocarbon because such solvents are much better solvents for the polymers of such monomers, especially conjugated diene polymers or blocks when they form a part of block copolymers.
As the polymer is created from the monomers, a solution of the polymer forms in the inert hydrocarbon solvent. This solution is called the polymer cement. These polymerizations may be carried out at a variety of solids contents and it is reasonably obvious that if the process can be run at high solids content, the manufacturing cost will be decreased because the cost of solvent will be decreased and more polymer can be produced in a given amount of time.
Unfortunately, with polymer cements of anionic polymers, one of the most significant rate limiting aspects is the viscosity of the polymer cement. This is especially true in the manufacture of block copolymers of conjugated dienes such as butadiene or isoprene and vinyl aromatic hydrocarbons such as styrene.
Solutions of living anionic polymers, living polymer cements, tend to be higher in viscosity than their terminated analogs, terminated polymer cements. The higher viscosity of living polymer cements in polymerization tends to limit the production capacity of equipment used to make these products. Higher concentrations of terminated polymer solutions could be pumped and mixed with the existing equipment but polymerization at these higher concentrations is not possible due to the prohibitively high viscosities of the living polymer solutions. Production rates are limited by the viscosity of the living anionic polymer solutions in polymerization since the polymer chain must be kept xe2x80x9clivingxe2x80x9d, i.e., not terminated, until the desired molecular weight is achieved.
The present invention is an improvement upon the known method of anionically polymerizing monomers by contacting the monomers with an anionic polymerization initiator which is an organo-substituted alkali metal compound. The improvement comprises decreasing the viscosity of the polymer cement by adding at least 0.01 equivalent of a metal alkyl compound per equivalent of alkali metal initiator if the metal alkyl is added before or at the beginning of polymerization. If the metal alkyl is added during the polymerization or after but before the living polymer is terminated, then at least 0.01 equivalent of the metal alkyl compound per equivalent of living polymer chain ends (i.e., styryl-lithium or dienyl-lithium moiety) should be used. Preferably, in both cases, from 0.01 to 1.5 equivalents is used and most preferably, 0.01 to 1.0 equivalents.
The metal alkyl is preferably added during the polymerization but it can be added before polymerization begins. It can also be added subsequent to polymerization before termination if desired. The alkyl groups of the metal alkyl are chosen such that they do not exchange with the organo substituents of the alkali metal, which can be the living polymer chain ends or the organo substituents of the initiator. To avoid this undesired exchange reaction, the alkyl groups of the metal alkyl compound are selected to be more basic and/or less bulky or both than the organo substituents of the alkali metal compound. The organo substituents of the alkali metal compound are aliphatic, cycloaliphatic, aromatic, or alkyl-substituted aromatic and include multi-functional initiators such as the sec-butyl lithium adduct of diisopropenyl. In a preferred embodiment of the invention, the organo-substituted alkali metal species at the time of the addition of the metal alkyl is a styryl-lithium or dienyl-lithium moiety. The preferred metal alkyl for use herein is triethyl aluminum.
This invention relates to anionic polymers and processes for polymerizing them by anionic polymerization using mono- or di- or multi-alkali metal, generally lithium, initiators. Sodium or potassium initiators can also be used. For instance, polymers which can be made according the present invention are those from any anionically polymerizable monomer, including random and block copolymers with styrene, dienes, polyether polymers, polyester polymers, polycarbonate polymers, polystyrene, acrylics, methacrylics, etc. Polystyrene polymers hereunder can be made in the same manner as the polydiene polymers and can be random or block copolymers with dienes.
In general, when solution anionic techniques are used, copolymers of conjugated diolefins, optionally with vinyl aromatic hydrocarbons, are prepared by contacting the monomer or monomers to be polymerized simultaneously or sequentially with an anionic polymerization initiator such as group IA metals, their alkyls, amides, silanolates, naphthalides, biphenyls or anthracenyl derivatives. It is preferred to use an organo alkali metal (such as lithium or sodium or potassium) compound in a suitable solvent at a temperature within the range from about xe2x88x92150xc2x0 C. to about 150xc2x0 C., preferably at a temperature within the range from about xe2x88x9270xc2x0 C. to about 100xc2x0 C. Particularly effective anionic polymerization initiators are organo lithium compounds having the general formula:
RLin
wherein R is an aliphatic, cycloaliphatic, aromatic or alkyl-substituted aromatic hydrocarbon radical having from 1 to about 20 carbon atoms and n is an integer of 1 to 4. The organolithium initiators are preferred for polymerization at higher temperatures because of their increased stability at elevated temperatures.
Other initiators that can be used herein include multifunctional initiators. There are many multifunctional initiators that can be used herein. The di-sec-butyl lithium adduct of m-diisopropenyl benzene is preferred because of the relatively low cost of the reagents involved and the relative ease of preparation. Diphenyl ethylene, styrene, butadiene, and isoprene will all work well to form dilithium (or disodium) initiators by the reaction:
Still another compound which will form a diinitiator with an organo alkali metal such as lithium and will work herein is the adduct derived from the reaction of 1,3-bis(1-phenylethenyl)benzene (DDPE) with two equivalents of a lithium alkyl:
Related adducts which are also known to give effective dilithium initiators are derived from the 1,4-isomer of DDPE. In a similar way, it is known to make analogs of the DDPE species having alkyl substituents on the aromatic rings to enhance solubility of the lithium adducts. Related families of products which also make good dilithium initiators are derived from bis[4-(1-phenylethenyl)phenyl]ether, 4,4xe2x80x2-bis(1-phenylethenyl)-1,1xe2x80x2-biphenyl, and 2,2xe2x80x2-bis[4-(1-phenylethenyl)-phenyl]propane (See L. H. Tung and G. Y. S. Lo, Macromolecules, 1994, 27, 1680-1684 (1994) and U.S. Pat. Nos. 4,172,100, 4,196,154, 4,182,818, and 4,196,153 which are herein incorporated by reference). Suitable lithium alkyls for making these dilithium initiators include the commercially available reagents (i.e., sec-butyl and n-butyl lithium) as well as anionic prepolymers of these reagents, polystyryl lithium, polybutadienyl lithium, polyisopreneyl lithium, and the like.
The polymerization is normally carried out at a temperature of 20 to 80xc2x0 C. in a hydrocarbon solvent. Suitable solvents include straight and branched chain hydrocarbons such as pentane, hexane, octane and the like, as well as alkyl-substituted derivatives thereof; cycloaliphatic hydrocarbons such as cyclopentane, cyclohexane, cycloheptane and the like, as well as alkyl-substituted derivatives thereof; aromatic and alkyl-substituted derivatives thereof; aromatic and alkyl-substituted aromatic hydrocarbons such as benzene, naphthalene, toluene, xylene and the like; hydrogenated aromatic hydrocarbons such as tetralin, decalin and the like; linear and cyclic ethers such as dimethyl ether, methylethyl ether, diethyl ether, tetrahydrofuran and the like.
It is known to polymerize such polymers with multifunctional initiators and then cap the living chain ends with a capping agent such as described in U.S. Pat. Nos. 4,417,029, 4,518,753, and 4,753,991, which are herein incorporated by reference. When such polymers formed with multifunctional initiators are polymerized and then capped, a polymer gel often forms. It is the subject of an earlier invention to prevent the formation of such gel by the addition of a trialkyl aluminum compound during the polymerization/capping process. The present invention only relates to reduction in viscosity of living polymer cement on addition of a metal alkyl and the improvement in polymerization process throughput that results from this viscosity reduction when using initiators of the type described above under the conditions described above and does not relate to the prevention of polymer gels during the manufacture of capped polymers using multifunctional initiators.
The presence of Cxe2x80x94Li chain ends (lithium being used herein as an example of an alkali metal used in the initiator) in the living polymer cements seems to contribute to the viscosity of the solution. Cxe2x80x94Li chain ends are the points in the molecule of the initiator where the carbon-lithium bond is located and at which the propagation of the polymer chain occurs and from which the polymer may continue to grow until it is terminated. It is known that lithium alkyls form aggregates in hydrocarbon solution. These aggregates are stabilized by metal-metal bonding between the lithium centers in the lithium alkyl moieties. Such aggregates likely are present in living anionic polymer solutions as well. The equilibrium between aggregated and unassociated polymer chains appears to strongly favor the aggregated species. The unassociated species, though present as a minor component of the mixture, appears to be the predominant and perhaps the only center for propagation of polymerization. For this reason, it is important that the exchange of polymer chains between aggregated and unassociated centers is fast relative to the rate of polymerization.
Aggregation of Polymer-Li Centers
The viscosity of a polymer solution is directly related to the molecular weight of the dissolved polymer. The aggregated moiety is n times larger in mass than the unassociated polymer, n representing the number of centers in the aggregate. For this reason, it is not surprising that the viscosity of a living anionic polymer cement (mostly aggregates) is higher than that of its terminated analog (as a terminated chain would have no Cxe2x80x94Li centers, it is reasonable to assume that it will not be aggregated). The strong association of the Cxe2x80x94Li chain ends in living anionic polymer solutions is likely the source of the very high viscosity for such solutions.
We have discovered that addition of selected metal alkyls to solutions of living anionic polymers can afford a substantial reduction in the viscosity of the living anionic polymer cement. It is preferred that the metal alkyl is selected form the group of metal alkyls that interact with Cxe2x80x94Li centers to form metal xe2x80x9catexe2x80x9d complexes. As an example of this type of interaction, see the equation below in which an aluminum alkyl is used as an example of the preferred type of metal alkyl and a living anionic polymer chain end as the preferred type of aggregation prone lithium species. The xe2x80x9cate complexxe2x80x9d is in equilibrium with the unassociated polymer chain. It is important that this complex is formed reversibly as the xe2x80x9cate complexxe2x80x9d is not capable of either initiating or propagating the polymerization of monomer.
Aluminate Complex Formation
It is our hypothesis that the added metal alkyl reduces the viscosity of a living anionic polymer solution by linking the two equilibria discussed above. See the equation shown below.
Mechanism for Reducing the Degree of Aggregation
The formation of the aluminate complex effectively drains away the aggregated polymer lithium moiety. The equilibrium concentration of aggregated species is reduced as more of the aluminate complex is formed. As the aluminate moiety is unassociated, this mechanism effectively reduces the concentration of aggregated species that is the principle contributor to viscosity in the living polymer cement. In this way, the viscosity of the living polymer cement is minimized. As more aluminum alkyl is added, more aggregated species are eliminated, up to the limit where all of the polymer is associated with the aluminum center. This appears to occur at about one aluminum alkyl per polymer lithium center. Added aluminum alkyl beyond one per polymer lithium center seems to have a diminished affect on the reduction of the viscosity of the living polymer cement and at least 0.01 equivalents of metal alkyl per 100 alkali metal centers must be added before any appreciable effect is noticed. Additional amounts of metal alkyl may be added but they do not significantly further reduce the viscosity of the cement while adding additional cost and reducing the rate of polymerization. Therefore, it is preferred that no more than 1.5 equivalents of metal alkyl be used, most preferably, no more than 1 equivalent. When the metal alkyl is added during or after polymerization, the basis is equivalents of living polymer chain ends. When the metal alkyl is added before or at the beginning of polymerization, the basis is equivalents of alkali metal initiator.
The selection of the alkyl on the metal center is important for the effective use of metal alkyls for the reduction of viscosity of a living anionic polymer cement if additional polymerization on the living anionic center is desired. As the formation of the metalate complex is reversible, alkyl groups must be selected which are not prone to dissociation to form RLi molecules. As outlined below using an aluminum alkyl for illustrative purposes, dissociation of the aluminate complex to form RLi and an aluminum alkyl attached to the polymer chain end is effectively a chain transfer mechanism for the polymerization reaction. The living polymerization center, a Cxe2x80x94Li moiety, has been transferred from the end of the polymer chain to the alkyl which was originally on the aluminum species.
Undesired xe2x80x9cChain Transferxe2x80x9d Reaction
The polymer aluminum alkyl moiety will be inactive under typical conditions for anionic polymerization of monomers. This polymer chain is essentially xe2x80x9cdeadxe2x80x9d for purposes of additional polymerization reactions. If the newly formed RLi species is not an effective initiator for polymerization of anionic monomers, the consequence of this reaction will be to stop the consumption of monomer and terminate polymerization. If, on the other hand, the newly formed RLi species is an effective polymerization initiator, this reaction provides a route to generation of a new anionic polymer, one not attached to the starting polymer chain.
For typical anionic polymerization processes that are often used to make block copolymers having well defined structures, all of these reactions are undesirable. Chain transfer processes like those described above interfere with the orderly process normally used for making well defined block copolymers with living polymerization systems. For such processes, it is desirable to minimize or eliminate these side reactions. It is desirable to select alkyl groups on the metal alkyls that are being used for purposes of reducing the living anionic polymer cement viscosity such that Polymer-Li species are the predominant, and desirably the only, species which are not associated with a metal ate complex.
At equilibrium, alkyl groups that are more basic will favor being attached to the more electronegative metal, the metal alkyl. Less basic alkyls will favor being attached to more electropositive metal, the alkali metal alkyl. The more electronegative metal is better able to stabilize the charge of a strongly basic alkyl anion. Consider the example shown below for the distribution of alkyl groups R and Rxe2x80x2 between lithium and aluminum centers:
Distribution of Alkyl Groups Between Li and Al Centers
The selection rule for whether RLi or Rxe2x80x2Li is the predominant unassociated lithium alkyl species present at equilibrium depends, in part, on which alkyl is more basic. A discussion of basicity in this context, and a table comparing the basicity of alkyl groups can be found in Chapter 8 of Advance Organic Chemistry, 4th Ed by Jerry March (Wiley and Sons, 1992), incorporated by reference. The basicity of alkyl moieties has been shown to follow the general trend outlined below:
Selection Rule for the Distribution of Alkyl Centers Between Li and Al
In a competition for the two metal centers, it is also reasonable to expect that more bulky alkyls will prefer to be attached to the monofunctional lithium center while less sterically encumbered alkyls will select the more highly substituted aluminum center.
In a practical application of these concepts, consider the case where a living polymer derived from the anionic polymerization of styrene or diene (styryl-lithium or allyl-lithium chain end) is treated with triethylaluminum (primary alkyl group). Formation of the ate complex should be facile but exchange of alkyls between the metal centers is not favored. The least basic and more bulky alkyl group, styryl-lithium or allyl-lithium, will stay on lithium while the more basic and less sterically encumbered alkyl, ethyl, will have an affinity for the aluminum center. This is a preferred system for viscosity reduction in a living anionic polymer cement where subsequent polymerization is desired. Aluminum alkyls having secondary or tertiary alkyls should work as well. While simple tertiary alkyl groups, such as t-butyl, can be considered bulky, these substituents are highly basic (as defined above) and would not be expected to participate in chain transfer reaction. Preferred embodiments include all combinations of living chains derived from typical anionicallyxe2x80x94polymerizable monomers such as butadiene, isoprene and styrene and most commerciallyxe2x80x94available trialkylaluminum compounds, including triethylaluminum, trimethylaluminum, triisobutylaluminum, tri-n-butylaluminum and tri-n-hexylaluminum. Arylaluminum compounds such as triphenylaluminum would be less preferred, as the phenyl ring is both less basic and fairly bulky. The addition of such a compound during polymerization of styrene or dienes may result in chain transfer. These same trends would expect to be observed for other metal alkyls that form ate complexes, such as magnesium and zinc alkyls.
Conversely, treatment of the s-butyllithium (secondary alkyl) polymerization initiator with triethylaluminum (primary alkyl) followed by addition of monomer (thus, addition of the metal alkyl before polymerization) should not be an effective polymerization system. This hypothesis was tested as outlined in a comparative example. As the ratio of triethylaluminum to sec-butyllithium was increased, the efficiency of the system for the initiation of the polymerization of styrene was reduced until at 1 mole of triethylaluminum for each mole of sec-butyllithium, the system was not able to initiate the polymerization of styrene. For this combination of alkyls, the more basic alkyl, sec-butyl, should have an affinity for Al while the less basic primary alkyl, ethyl, would be expected to favor the lithium center. When a molar equivalent of triethylaluminum has been added, all of the sec-butyllithium has been converted to ethyllithium which is inactive as a polymerization initiator. Since ethyllithium is an ineffective initiator of styrene polymerization, the alkyl exchange reaction has worked to remove the only effective polymerization initiator in the system, sec-butyllithium.
If the objective is to retain the living nature of the polymerization and reduce the viscosity of the cement, then more care must be exercised in the selection of the metal alkyl that is to be added to the Polymer-Li solution. In particular, the alkyl group on the xe2x80x9catexe2x80x9d complex forming metal alkyl that is to be added must be more basic and/or less bulky than the Cxe2x80x94Li chain end (usually styryl-Li or dienyl-Li or allyl-Li) of the living polymer. This additional requirement for the viscosity reduction agent will insure that the undesired side reaction of chain transfer will be avoided or at least minimized. In this way, viscosity reduction can be obtained without a loss in polymerization capability.
Alkyls of aluminum, zinc, boron (especially trialkyls such as triethylborane), and magnesium, and combinations thereof, should all be effective for this purpose. Preferably, the alkyls have from 1 to 20 carbon atoms per alkyl substituent. Preferably, the metal alkyl is selected from the group consisting of trialkyl aluminum, dialkyl magnesium, and dialkyl zinc compounds. Preferred trialkylaluminum compounds are triethylaluminum, trimethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, trisobutylaluminum, tri-n-hexylaluminum, and trioctylaluminum because these reagents are readily available in commercial quantities. Triethylaluminum is most preferred as it is least expensive on a molar basis. Preferred dialkylmagnesium compounds are butylethylmagnesium, di-n-butylmagnesium, and di-n-hexylmagnesium because these reagents are readily available in commercial quantitites. Preferred dialkylzinc compounds are dimethylzinc, diethylzinc, di-n-propylzinc, diisobutylzinc, and di-n-butylzinc because these reagents are readily available in commercial quantities.

Increased throughput in the manufacture of anionic polymers by reduction in polymers by reduction in polymer cement viscosity through the addition of metal alkyls


A weed trimmer and edger apparatus and method for cutting, edging, and lawn maintenance in general. In one embodiment, the apparatus is an attachment for a riding lawnmower. At least one belt and pulley attach to the lawnmower to power and rotate a cutting head arrangement, which is supported by a bracket attached to the lawnmower. In another embodiment, the apparatus is a standalone portable weed trimmer and edger apparatus with a cutting head arrangement powered by an electric motor. The cutting head arrangement may comprise a rotating shaft contained within a stationary housing with a disc attached to an underside portion of the shaft. Weed eater line descends from a storage housing on an upper portion of the apparatus through a feed mechanism which advances or retracts weed eater line through the apparatus.

Field of the Invention
The present invention relates generally to lawn mower attachments, and more specifically to a weed trimmer and edger attachment for riding lawnmowers.
Background of the Invention
Lawn maintenance and upkeep is a common concern in many residential and commercial settings. This maintenance may include cutting grass, trimming weeds, edging along fence lines or property boundaries, and the like. Oftentimes, there is numerous equipment to accomplish the many tasks associated with lawn maintenance, including a lawn mower, an edger, a weed trimmer or weed eater, a blower, and the like. This equipment requires maintenance itself and can be cumbersome to handle and transport.
Large areas are more problematic, because of the increased area needed to be reached by the weed trimmer and the need to haul this equipment around the property. Furthermore, these devices generally feed the cutting string from a position below the cutting axis, such as storing the cutting string in a head portion which fastens to the rest of the machine with the cutting string deployed through various orifices. While weed eater attachments can be utilized with lawn mowers and the like, the resulting devices can be problematic.
Prior art weed eaters provide a feed for additional string as the string is worn that is provided in a supply beneath the weed eater machine. The position of the supply can be problematic if feed problems arise due to difficulty of access to the feed supply for a riding weed eater mower attachment.
Numerous attempts to produce a weed trimmer and edger attachment for lawnmowers exist in the prior art. The following patents discuss background art related to the above discussed subject matter:
U.S. Pat. No. 8,464,504, issued Jun. 18, 2013 to Huff, discloses a combination edger and trimmer for mounting on a riding lawn mower's deck. The edger/trimmer comprises a deck mount plate, an intermediate plate and a motor mount plate. The three plates are offset from one another with the intermediate plate hingeably attached to the deck mount plate and also to the motor mount plate. An electric motor with a cutting head is attached to the motor mount plate. The edger/trimmer is positioned in rest, edging, or trimming positions by manually moving the plates about their hinge points.
U.S. Pat. No. 8,322,121, issued Dec. 4, 2012 to Marcell, discloses an electric trimmer attachment for lawn tractors comprising an attachable apparatus for use with existing lawn tractors which provides trimmer capabilities. The apparatus comprises a mounting bracket, an arm, and a line trimmer. The mounting bracket provides a means for removably securing the device to a deck of an existing mower. The arm comprises a gooseneck arm attached to the bracket, which extends outwards. An outside end portion of the arm comprises a line trimmer with an electric motor and features such as automatic line advancement and safety controls. The motor is powered via a converter or battery pack on the mower. The arm provides an arc-shaped rotating motion to the trimmer.
U.S. Pat. No. 8,302,372, issued Nov. 6, 2012 to Eubanks, teaches an auxiliary trimmer for a lawnmower including a mounting plate removably fastened to a lawnmower deck. Attached to the mounting plate is a trimmer housing having a shaft extending therefrom. At a distal end of the shaft is a trimmer spool that is driven by the lawnmower blade with a series of belts and pulleys. On the rear surface of the trimmer housing is an adjustment ring having a plurality of notches thereon. A spring-biased latch on an end of the shaft releasably fits within any one of the notches on the adjustment ring to position the trimmer spool at a select angular orientation. A pivotal handle raises and lowers the trimmer spool to a desired elevation.
U.S. Pat. No. 7,900,428, issued Mar. 8, 2011 to Maldonado, discloses a gear assembly which may have a first gear attached to a gear shaft and a second gear attachable to a powered rotating element of a mowing machine. An attachment element may have a shaft hole with the gear shaft rotatably inserted through the shaft hole with one end of the gear shaft positioned in a coupling end of the attachment element. A trimming device with a trimmer tube open at a first end and an end of a shaft of the trimming device with a shaft socket fitting inserted in the coupling end of the attachment element for the shaft socket fitting to engage the gear shaft. An anti-rotating clamp attached adjacent the first end of the trimmer tube for positioning and retention in a clamp recess in a front face of the coupling end to inhibit rotation of the trimmer tube in the coupling end.
U.S. Pat. No. 4,453,372, issued Jun. 12, 1984 to Remer, teaches a universal grass edger and trimmer attachment utilizing a rotary flexible drive shaft whose operating end is supported by a multipositional boom.
United States Patent App. No. 2010/00326031, published Dec. 30, 2010 to Branden, discloses a device allowing a user to removably attach a weed line trimmer to a lawnmower deck, allowing a user to activate the weed trimmer or automatically engaging during the mowing of a yard to trim areas beside the mower while mowing the yard, eliminating duplicate effort and also to relieve the stress of carrying the weed trimmer.
United States Patent App. No. 2004/0154277, published Aug. 12, 2004 to Shumate, discloses a trimming and edging attachment for all types of riding mowers and garden tractors used for residential and commercial needs. The attachment consist of a mounting plate to mount to the front of the mower with three sections of arms extending outward to the left of said mower and just ahead of the left front wheel. The trim head is powered from an engage mechanism with a drive belt off of the main shaft of the mower motor. The power of the pneumatic cylinders that operate the up and down motion of the arms comes from a twelve volt dc motor and pump combination. This pump is an on demand pump and only operates when some type of adjustment or movement is needed. This unit does not depend on the mowing deck to be in operation while using the trim and edge attachment.
There exists a need for an improved weed trimmer attachment for riding lawnmowers. Consequently, those skilled in the art will appreciate the present invention.

Weed trimmer and edger attachment for riding lawnmowers


A spatial light modulator may include a plurality of deflectable modulating elements. Each of the deflectable modulating elements may further include a support structure, an electrostatically deflectable mirror element and at least one electrode. The mirror element may be set to a deflection state by charging and selectively discharging a capacitor coupled to the at least one electrode.

1. Field of the Invention
Example embodiments of the present invention relate to spatial light modulators (SLMs) and methods for addressing the same.
2. Description of the Related Art
Related art micro-electromechanical systems (MEMS) may include movable mirrors fabricated on wafer substrates using micro-electronic processing techniques. In these related art MEMS, electrostatic actuation may be used to deflect the micro-mirrors. For example, a voltage may be generated between two electrodes, one of which is stationary and the other of which positioned on the mirror, in order to produce a force between the two electrodes.
A related art SLM with an array of actuators (e.g., micro-mirrors, reflecting elements, modulating elements, pixel elements, etc.) used in, for example, a mask writing tool or a chip manufacturing tool may be loaded with a specific pattern. Each actuator may be in an addressed state or a non-addressed state before respective stamps may be printed. This pattern may be a subset of the pattern to be printed on the mask or chip, respectively. Each actuator mirror may be deflected electrostatically by applying voltage between the mirror and an underlying address electrode, after which the actuator mirror may move into a deflected state before an electromagnetic radiation source may be triggered to print the stamp.
An SLM may be loaded in an analogue mode by applying one potential to the mirrors and individually addressing at least one electrode belonging to each of the mirrors in order to create a pattern of the SLM. In the analogue mode, the SLM mirror may be set to a number of different states, for example, 64 or 128 states ranging from non-deflected (e.g., completely non-deflected or minimum deflection) to a higher (e.g., maximum) deflection. A maximum deflection may be a state in which little or no electromagnetic radiation impinges on the micro-mirror, and minimum deflection may be defined as full reflection of the impinged electromagnetic radiation.
In a related art digital SLM, maximum deflection may be when the reflected electromagnetic beam is deflected out of the target plane and minimum deflection may be full reflection of the impinged electromagnetic radiation. Related art digital SLMs operate in a deflection mode, while related art analogue SLMs operate in a diffraction mode. The degree of deflecting individual elements may vary between those digital and analogue SLMs, where the analogue SLMs may be deflected parts of a degree and the digital SLMs may be deflected several degrees.
FIG. 3 illustrates a side view of a related art actuator 300. As shown in FIG. 3, the actuator structure 300 may be, for example, a micro-mirror structure in a spatial light modulator (SLM), and may include a substrate 313, a first electrode 312, a second electrode 314, a support structure 311 and a movable element 310. The substrate 313 may be made of semi-conducting material and may comprise one or a plurality of circuits (e.g., CMOS circuits). The first and second electrodes 312 and 314 may be made of an electrically conductive material, for example, gold, copper, silver, alloys thereof and/or other electrically conductive materials. The electrodes 312 and 314 may be connectable to steering circuits, such as, the above-mentioned circuit.
The support structure 311 may be manufactured of a stiff (e.g., relatively stiff) material, for example, single crystal silicon or any similar, or substantially similar materials. The movable element 310 may be manufactured of a material having suitable (e.g., good) optical properties, for example, aluminum or any other suitable metallic material. Alternatively, a material without the above characteristics may be coated with one or a plurality of other materials having suitable characteristics, and a sandwich structure may be created.
An electrostatic force may deflect the movable element 310. Applying different potentials on the movable element 310 and the first electrode 312 or second electrode 314 may create electrostatic force. When a first potential is applied to the movable element 310 and a second (e.g., different) potential is applied to the first and second electrodes 312 and 314, an electrostatic force may be generated, but may not deflect the movable element 310, for example, because the attractive force, which may be attractive independent of the polarity of the potential difference, between the first electrode 312 and the mirror may be equivalent, or substantially equivalent, to the attractive force between the second electrode 314 and the same mirror. The two attractive forces may equalize each other.
In FIG. 3 the actuator structure may include the first 312 and second 314 electrodes. However, deflecting the movable element 310 may require one electrode, either the first electrode 312 or second electrode 313. However, two electrodes arranged spaced apart from each other may allow the mirror to be deflected in two different directions.


Systems and methods to determine vehicle safety conditions are provided. Techniques include receiving one or more vehicle conditions from vehicle sensors and sending the data to a centralized server. The data is aggregated based on vehicle identifier and location to determine the type and location of the safety condition. The determined safety condition is sent to one or more vehicles in the vicinity of the determined safety condition to alert the drivers of the hazard. The safety condition can be displayed as an overlay on a map to aid the driver in locating it.

Currently, standard vehicles offer drivers only the information that the driver can see. Some vehicles have sensors that can assist drivers, but these sensors are confined to the particular vehicle and can operate only over a short distance. There is a need to improve driving safety by enabling drivers to know of safety risks that are not in their line-of-sight.


A safety needle device and positive flush mechanism for use with a vascular access port. In one embodiment, the combination needle assembly includes a needle, a body and a base, the body being collapsible to expunge fluid therefrom as the needle is withdrawn from a vascular access port. In another embodiment, the combination needle assembly includes a needle, a housing and a reservoir, the housing squeezing the reservoir to expunge fluid therefrom as the needle is withdrawn from the port. In another embodiment, the needle assembly includes a compression plate and balloon extension, the compression plate forcing fluid out of the balloon extension as the needle is withdrawn from the port. In all embodiments, the needle assembly is configured to provide a positive flush to overcome negative pressures in the vascular access port, while also providing a locking mechanism to prevent accidental needle sticks.

The present invention relates generally to medical devices and more particularly to needle safety devices and positive flushing mechanisms.
Implantable vascular access systems are used extensively in the medical field to facilitate the performance of recurrent therapeutic tasks inside the body of a patient. Such vascular access systems generally include an implantable vascular access port attached to a vascular catheter. A typical vascular access port has a needle-impenetrable housing that encloses a fluid reservoir that is accessible from the exterior of the access port through a needle-penetrable elastomeric septum.
The entirety of the system, both the vascular access port and the catheter attached thereto, is implanted in the body of a patient. The distal tip of the catheter is disposed at a predetermined location where therapeutic activity is to be effected. Once the vascular access system is implanted, the tip of a hypodermic needle can then be employed selectively and repeatedly to access the fluid reservoir of the access port by penetrating the skin at the implantation site for the access port and then by being advanced through the septum of the access port itself.
While often times syringe-type devices are utilized for vascular access ports in acute or short-term situations, a special type of device is utilized for longer term infusion therapy. Such an infusion assembly device generally consists of a needle and wing assembly that lies flat against the skin in an insertion position, the needle having a proximal end attached to a wing assembly that is in angular relation to the needle shank, the angle being approximately 90°. As mentioned, when this longer term needle device is inserted into the vascular access port, it lies flat against the patient's skin and is adhered thereto as described, for example, in U.S. Pat. No. 4,710,176 to Quick.
With respect to the needle tip of the needle used in infusion assemblies for vascular access ports, a non-coring configuration is generally utilized due to repeated entry of the needle into the septum of the vascular access port. When the tip of a hypodermic or other traditional needle advances through the septum, coring occurs if any portion of the septum material is forced inside the shaft of the needle through the opening in the tip thereof. That portion of the septum material forced inside a needle in this process is in effect severed from the rest of the body of the septum material. Such septum coring produces small, detached particles of the septum that are likely to enter the fluid that is infused by the implanted vascular access system into the vascular system of the patient. These particles can obstruct fluid flow through the outlet stem of the vascular access port, or if escaping through the outlet stem of the vascular access port, can become trapped in the cardiovascular system of the patient.
In addition, septum coring produces small passageways through the body of a septum. On occasion these passageways extend entirely through the septum, from the exterior thereof to the fluid reservoir inside the vascular access port. The inwardly directed forces imposed on the installed septum by the housing of a vascular access port should initially urge the material of the body of the septum inwardly upon itself to close such passageways after the shaft of the needle is withdrawn therefrom. Nonetheless, continued coring eventually leads to various forms of septum failure that cannot be overcome by such inwardly directed forces. The material continuity of the septum is increasingly compromised, resulting in crumbled areas of the septum matrix. Eventually, leakage of fluid can be expected through the septum from the fluid reservoir in the vascular access port. Once such fluid escapes to the exterior of the vascular access port, necrosis will occur of the tissue surrounding the subcutaneous pocket in which the vascular access port is implanted, causing many undesirable consequences. Therefore, non-coring or Huber needles are preferably used in conjunction with infusion assemblies for vascular access ports. These needles, in contradistinction to the standard or traditional hypodermic needles pierce the septum like a knife, facilitating the resealing thereof so that the aforementioned problems are largely averted.
As with any needle-type device, there exists the problem of inadvertent needle sticks, which generally occurs when the needle-type device is withdrawn from the patient prior to appropriate disposal thereof. Of course, inadvertent needle sticks introduce a variety of concerns due to unwanted transmission of blood from the patient to the medical practitioner. Inadvertent needle sticks can occur because of carelessness on the part of the medical practitioner or due to accidents in the handling of devices with exposed needle tips. With respect to Huber needles specifically, needle stick accidents can occur due to difficulty in removal as well. This difficulty results from the configuration of the Huber needle, which gets hooked into the port making it difficult to remove. Increased pulling force on behalf of the medical practitioner to dislodge the needle from the port results in less control over the tip of the needle when freed from the port, causing the inadvertent needle stick.
To address the inadvertent needle stick problem in winged infusion assemblies, such as those described herein, various safety devices have been designed to encase the needle after it is withdrawn from the port. One such safety device is described in U.S. Pat. No. 5,755,694 to Camus. Camus discloses a needle base disposed over a segment of the needle at its proximal end, comprising two generally flat wings made of flexible material with one hinge connecting each of the wings to the needle base. Upon removal of the needle from the patient the wings flex against a moveable member that keeps them adjacent the needle until the needle is completely removed from the skin of a patient after which the wings surround the needle to prevent the tip from making contact outside of the needle base.
Another type of safety device is described in U.S. Pat. No. 5,951,522 to Rosato et al., in which the particular configuration of the Huber needle is also taken into account. Rosato et al. discloses a safety enclosure comprising a wing assembly mounted to the aft end of a angled Huber needle, the wing assembly having a configuration consisting of either a single integral member having a plurality of spaced apart fold lines which divide the member into a plurality of interconnected panels, or a pair of wing members mounted in a scissors-type arrangement. In each embodiment, when the medical practitioner removes the needle from the patient, the wing assembly closes around the needle and locks together, encasing it therein.
While many advancements have been made in the area of needle devices for use with vascular access ports, such as those described herein, there remains a heretofore unsolved problem related to removal of the needle device from the vascular access port. When the needle is inserted through the septum, it occupies a volume equal to the external dimensions thereof present in the fluid reservoir positioned underneath the septum. When the needle is removed from the vascular access port, the needle volume is evacuated without replacement, causing an equivalent volume of venous fluid to be drawn into the catheter tip at the distal end thereof. This infiltration of venous fluid is suspected to cause or contribute to thrombus formation at the catheter tip, which blocks the flow of fluid therethrough and results in early removal of the port and catheter from the patient. Early removal is costly, invasive and time-consuming and otherwise extremely undesirable.
One solution to this problem of unwanted venous fluid being drawn into the catheter tip has been to implement a positive flushing technique as the needle is withdrawn. This technique generally consists of the medical practitioner inserting a syringe into the port and injecting a solution such as heparin while simultaneously withdrawing the needle. This technique, however, can be quite cumbersome and complicated and in fact may require more than one operator, as many of the infusion sets for use with vascular access ports require two hands to withdraw. For these reasons and others, it is known that a significant population of medical practitioners forego the practice of the described technique despite the adverse consequences that could result, as outlined herein. Therefore, it would be desirable to incorporate a flushing mechanism into a needle infusion set for use with a vascular access port so that flushing upon removal of the needle from the septum is assured.
In particular, it would be desirable to incorporate a positive flushing mechanism into various needle assemblies, one of which being an improved infusion needle assembly for use with a vascular access port that also provides a safety feature to prevent needle sticks.


A filter assembly configured for acoustic dampening for use with compressor assemblies such as oxygen concentrators including a compartmented housing member having an inlet opening, an outlet opening, a filter member, and a plurality of noise attenuating members positioned and located therewithin. The configuration of the compartmented housing member in conjunction with the positioning and location of the filter member and the noise attenuating members therewithin all contribute to absorb and dissipate any sound waves generated within the housing member due to air flow movement therethrough. This substantially reduces and minimizes noise associated with the present filter assembly.

This invention relates generally to filter assemblies and, more particularly, to various embodiments of a filter assembly configured for acoustic damping for use in compressors such as oxygen concentrators and other medical applications in the home care medical equipment industry.
Oxygen concentrators are commonly used in the care of respiratory patients, particularly, in the home care environment, to provide sufficiently high purities of oxygen to the patient without using high pressure tanks or liquid oxygen. Oxygen concentrators utilize ambient atmospheric air as their source of oxygen in conjunction with an absorption system such as one or more molecular sieve beds to separate oxygen from the other gases found in the air and to provide that oxygen in concentrated form to the patient. Atmospheric air typically includes approximately 80% nitrogen and 20% oxygen. Nitrogen is absorbed by the absorption system and is retained therein until subsequently purged.
Typically, atmospheric air is drawn into an oxygen concentrator from the ambient environment. Such ambient air is then passed through a filter assembly to remove dust and other contaminants, and the filtered air is then pressurized by a compressor for introduction into the absorption system. Once the compressed air is introduced into the absorption system, the nitrogen is selectively absorbed and released to atmosphere leaving the residual oxygen available for patient use. The absorption system is then regenerated and made ready for the next cycle. Oxygen concentrators typically produce an oxygen concentration usually in the range of 90–95%.
Use of an effective filtration system for purging contaminants from any liquid or gas is always important for a multitude of obvious reasons. Properly and effectively filtering the incoming ambient air before it is compressed and introduced into the absorption system of an oxygen concentrator is likewise important because effective filtration not only improves the overall efficiency of the oxygen concentrator but it also improves and increases the oxygen concentration provided to the patient. Poor filtration of the incoming air also subjects the oxygen concentrator and its associated compressor to excessive wear from particles which contaminate the system thereby decreasing service life while increasing maintenance.
Routine maintenance also includes changing the filter assembly at some point in time when the filter is dirty and no longer functional within certain parameters. It is often difficult to determine when the filter assembly should be changed because the filter element is often times hidden and concealed within an opaque housing structure. As a result, such filters are often replaced at a predetermined regular time interval regardless of the actual condition of the filter element. This is not economical or efficient since, depending upon the type and amount of use of the oxygen concentrator, the filter element may still be operable and may still have additional useful life when it is replaced at the predetermined time interval. A better mechanism for identifying when the filter element should be changed is needed.
Still further, the type and size of compressor associated with an oxygen concentrator determines the overall oxygen flow rate capacity as well as the level of noise produced by the system during operation. In general, large compressors required for providing higher rates of oxygen can be quite noisy. Also, such oxygen concentrators are typically used at home, or in a hospital or nursing home type environment, where noise generation can be a problem. Despite the fact that efforts are made to insulate and dampen the noise for the compressor, the sound generated is often excessive. Noise attenuation is therefore always an issue.
It is therefore desirable to provide a filter assembly which improves the air filtration process to the absorption system of an oxygen concentrator or other compressor assembly, which includes means for determining when to change the filter assembly, and which includes means to reduce and dampen the overall noise level associated with the operation of an oxygen concentrator or other compressor assembly.
Accordingly, the present invention is directed to a filter assembly which overcomes one or more of the problems as set forth above.

Home Health Medical Equipment Incorporated


Methods and network devices are provided for forwarding a message in a layer 2 edge network that includes an access server device connected to sender and gateway devices. Forwarding information including destination IP address, destination MAC address, destination VLAN ID and destination device ID is established. A message is received by the access server device from the sender device. The message includes first destination MAC address, first destination IP address, first destination VLAN ID, and first destination device ID. When the first destination MAC address of a received message is a MAC address of the gateway device, the received message is forwarded according to the first destination MAC address, first destination VLAN ID and first destination device ID. Otherwise the message is modified and forwarded according to second destination MAC address, second destination VLAN ID, and second destination device ID determined to be associated with the first destination IP address.

A data centre edge network serves as a boundary to the data centre. The edge network is connected to host devices or servers on one side, and to an edge router that serves as an outgoing interface to an external network on the other side. A first-hop gateway of the edge network may implement a redundancy protocol for establishing a fault-tolerant gateway, such as VRRP (Virtual Router Redundancy Protocol), HSRP (Hot Standby Route Protocol) etc. The fabric core of an edge network may be implemented as a layer 2 virtual private network (L2VPN). In this case, from a global perspective, the L2VPN domain may be viewed as a single virtual device such as a layer 3 switch.
Traffic forwarding within a layer 2 network of a data centre may use any suitable network protocol such as SPB (Shortest Path Bridge), TRILL (Transparent Interconnection of lots of link), VPLS (Virtual Private Label Switch) etc. These techniques support layer 2 traffic forwarding according to ECMP (Equal Cost Multi Path), shortest path and transparent switching. Internal layer 2 traffic forwarding is by way of L2VPN forwarding between physical devices. Layer 2 and layer 3 forwarding is performed via the edge network.

Traffic forwarding in a layer 2 edge network


A method of manufacturing a semiconductor device may include, but is not limited to the following processes. A first recess is formed in a semiconductor substrate to define an active region on the semiconductor substrate. The active region includes a protruding portion of the semiconductor substrate surrounded by the first recess. The protruding portion has a sloped side surface. A first insulating film that fills the first recess is formed. A gate recess is formed in the active region to form a thin film portion that upwardly extends. The thin film portion is positioned between the gate recess and the first insulating film. The thin film portion is a part of the protruding portion. An upper part of the thin film portion is removed by wet-etching to adjust a height of the thin film portion.

1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor device.
Priority is claimed on Japanese Patent Application No 2009-231725, filed Oct. 5, 2009, the content of which is incorporated herein by reference.
2. Description of the Related Art
With the miniaturization of semiconductor devices, the gate length of MOS transistors has been reduced. Regarding planar MOS transistors, the reduction in the gate length causes the short channel effect. Consequently, the threshold voltage is reduced, thereby causing an increase in off-current.
Japanese Patent Laid-Open Publication No. 2007-158269 discloses a semiconductor device and a method of manufacturing the same. The semiconductor device includes a channel portion between an STI (Shallow Trench Isolation) region and a gate trench. Japanese Patent Laid-Open Publication No. 2007-258660 discloses a semiconductor device including a recessed channel region and a method of manufacturing the same.
The semiconductor devices of the above related art include a recessed channel region between a recessed gate electrode and an element isolation region. Hereinafter, such transistors as disclosed in the above related art are referred to as RC (Recessed Channel) transistors.
Japanese Patent Laid-Open Publication No. H09-232535 discloses a method of manufacturing a semiconductor device in which a photolithography process for forming a trench and a photolithography process for forming a gate electrode are carried out in one process. Compared to the trench gate transistor, which is formed by simply embedding a gate electrode in a trench, the RC transistor is a higher performance transistor that can prevent a decrease in the threshold voltage and increase the on-current as much as possible.
The operation characteristics of the RC transistor vary according to the shape and height of the channel region adjacent to a side surface of the recess. It is important to optimize the shape and height of the channel region of the RC transistor according to the electrical characteristics required for a device to which the RC transistor is applied.
Regarding the methods of the related art, however, it has been difficult to precisely adjust and properly process the shape and height of the channel region. Further, a bur portion is likely to remain. The bur portion is a thin semiconductor layer, which covers a side surface of the element isolation region. For this reason, it has been difficult to remove the bur portion while maintaining the shape and height of the channel region.
Japanese Patent Laid-Open Publication No. 2007-194333 discloses a method of removing a bur portion (Si bur) which remains and covers a side surface of an element isolation region of a trench gate transistor. The bur portion affects operations of the trench gate transistor. However, an object of the method is to completely remove the bur portion or to reduce the size of the bur portion to 10 nm or less. For this reason, the amount of the removed silicon substrate is so large. Therefore, the method of the related art cannot be applied to an RC transistor including, as a channel region, a semiconductor layer forming a Si bur portion.
Thus, according to the methods of the related art, it has been difficult to adjust the height of the channel region of the RC transistor to be in a desired range. Further, it has been difficult to completely remove the bur portion remaining adjacent to the channel region.

Method of manufacturing semiconductor device


A system and method for providing high speed emulation of a computer system by transforming selected target instructions and bypassing target instruction decoding for those target instructions which have been transformed. A target computer system, controlled by a plurality of target instructions, is emulated on an emulation host computing system. Target instructions are successively loaded into the emulation host computing system in the order that the target instructions would be executed. The target instructions are decoded to identify the functions designated by the target instructions, and these functions are executed by the emulation host computing system. Emulation information is assigned to selected target instructions, where the emulation information controls execution of these selected target instructions, referred to as transformed instructions. Software routines identified by the emulation information are initiated for these transformed instructions, where the software routines execute the functions of the target instruction in the machine language of the emulation host computing system.

Computer emulation involves emulating a target computing system with a different computer system. There are various reasons for emulating a computer system, including testing, or debugging, the program code associated with the computer system. Another reason is that when a computer center is updated with different computing systems, the problem of program compatibility becomes acute.
Computer systems that have become obsolete may include program code which is not compatible with other computing systems which might be used to replace the obsolete system. When computers become obsolete, or are replaced for any reason, the users want to run their old programs on the new machine without having to rewrite them. These programs can be moved to the new machine provided that the new machine can simulate the execution of each individual instruction as well as the registers and hardware features of the old machine. This can be accomplished by providing the new programming level with an interpreter for executing programs in the old machine language. The interpreter for the old machine is typically referred to as an emulator.
There are various types of emulation available, including interpretive emulation and compiled emulation. The interpretive execution approaches uses an interpreter to decode each target computer instruction and call a routine to emulate each of the operations that would have been performed by the target system. This approach is effective, but slow. Emulating hardware functions is time consuming because hardware can perform many functions in parallel, while software must perform the same functions serially.
The compiled execution approach is faster than the interpretive approach. For compiled execution, a compiler analyzes object code instructions and converts them into native mode routines which perform the same function.
However, these emulation techniques still do not handle all situations, and still operate at less than desirable speeds. Emulation of object code by execution of pre-compiled instructions is not practical when there is a mixture of instructions and data within a memory bank, as the compiler is unable to differentiate between them. It is also not practical where instruction modification is allowed. Instruction modification (also referred to as self-modifying code) refers to the modification of the program as the program is executed. Although this technique is generally disfavored today, system still exist with such self-modifying code, and the compiled execution approach does not handle such a situation well.
It is therefore desirable to provide very fast emulation of the target computing system, and to manage situations such as instruction/data mixtures and self-modifying code. The present invention provides a new approach called "transformed execution", that utilizes transformed instruction and data banks which in turn allows certain emulation steps to be bypassed, thereby increasing emulation efficiency and performance. The present invention provides numerous advantages over the prior art, including selectable execution performance based on transformation time and storage space tradeoffs, wherein high performance transformations can be directed at high usage banks or instructions, and slower (more space saving) transformations can be directed to lower usage banks or instructions. Instruction modification is allowed, and the original instructions are never destroyed or modified by the transformation. The transformed banks are portable, and allow for a mixture of instructions and data. Improvements in transformation techniques can be included without user intervention, by implementing additional emulation code and selecting a new level of transformation.
The present invention provides a solution to the aforementioned problems, and offers other advantages over the prior art.

Selective emulation interpretation using transformed instructions


A field oxide region and method of forming a field oxide region using a LOCOS process and nitride spacers formed on the sidewalls of the field oxide regions. During the LOCOS process recesses are formed in the field oxide which result in poor step coverage during successive process steps. Nitride spacers are formed on the sidewalls of the field oxide covering the recesses. The spacers provide a smooth surface over the field oxide and improved step coverage during subsequent process steps.

(1) Field of the Invention
This invention relates to the formation of field oxide isolation regions using local oxidation of silicon and more specifically to the use of nitride spacers to provide a smooth surface on the field oxide to improve step coverage of subsequent process steps.
(2) Description of the Related Art
U.S. Pat. No. 5,399,520 to Jang describes the use of nitride films and trenches formed in the integrated circuit substrate to form field oxide isolation regions. The processes and structure are different from the invention of this Patent Application.
U.S. Pat. No. 5,393,694 to Mathews describes the use of polysilicon to fill recesses in the field oxide isolation regions. The processes and structure are different from the invention of this Patent Application.
A paper entitled "Reverse Elevated Source/Drain (RESD) MOSFET for Deep Submicron CMOS," by J. R. Pfiester et al., IEDM 92, pages 885-888 describes the use of disposable nitride spacers to define selective silicon offset from the gate edge prior to Lightly Doped Drain implantation in a new Reverse Elevated Source/Drain CMOS device.
A paper entitled "IMPACT OF LDD SPACER REDUCTION ON MOSFET PERFORMANCE FOR SUB-.mu.m GATE/SPACE PITCHES," by Carlos Mazure et al., IEDM 92, pages 893-896 describes the use of nitride spacers and LPCVD TEOS spacers in forming MOSFET devices having sub micron gate/space pitches.
The invention of this Patent Application uses nitride spacers formed on the sidewalls of field oxide regions to fill the recesses formed in the field oxide by over etching thereby providing a smooth surface for subsequent process steps.

LOCOS field oxide and field oxide process using silicon nitride spacers

Taiwan Semiconductor Manfacturing Company, Ltd.


A method for fabricating an anisotropic conductive substrate is disclosed. A back holder has metal pins on a surface thereof. A liquid compound is formed on the surface of the back holder with metal pins. The liquid compound is pressed to deform the metal pins into electrodes in the liquid compound. The thickness between upper surface and lower surface of the liquid compound is between 25 μm and 250 μm. The electrodes have upper ends and lower ends exposed from upper surface and lower surface of the liquid compound to provide electrical contact of anisotropic conduction.

The conventional printed circuit board is made of glass fiber reinforced resin, and is laser-drilled through its upper and lower surfaces to make through holes. A layer of metal is filled in the drilled through holes by electroplating to attain to vertical electrical connection. The electroplated metal layer covers the entire surface of the printed circuit board including the drilled through holes, therefore it cannot be provided for anisotropic electrical connection unless the metal layer connecting high-pitch via went through a highly accurate etching processes.
Conventionally Anisotropic Conductive Film (ACF) is an adhesive film with anisotropic conductivity, which is used in the connection and adherence of electrical devices, such as the anisotropic conductive film disclosed in U.S. Pat. No. 6,344,156 entitled "ANISOTROPIC CONDUCTIVE ADHESIVE FILM". The anisotropic conductive adhesive film is used in outer lead bonding (OLB), bump connection of the Tape Carrier Package (TCP) or combination of IC chips with the LCD panels by Chip-On-Glass bonding. The anisotropic conductive film is an insulating resin containing conductive particles properly. To acquire vertical conductivity, the conductive particles must have same size and with uniformity distribution. Meanwhile, the electrical devices should have extruded electrodes, such as bumps or pillar, to stick into the anisotropic conductive film. When the distance between the extruded electrode and outer circuit board is close enough corresponding to the diameter of an electric particle, the anisotropic conductivity can be acquired. Therefore, the conventional anisotropic conductive film is used in the adherence of electrical devices and outer circuit board, but it is improper to an interposer between semiconductor burn-in testing apparatus and wafer under test due to adhesion and reactivity of the anisotropic conductive film.

Method for fabricating anisotropic conductive substrate