180 results about "Chain termination" patented technology

A method for identifying nucleic acid ligands to target molecules using the SELEX procedure wherein the candidate nucleic acids contain photoreactive groups and nucleic acid ligands identified thereby are claimed. The complexes of increased affinity nucleic acids and target molecules formed in the procedure are crosslinked by irradiation to facilitate separation from unbound nucleic acids. In other methods partitioning of high and low affinity nucleic acids is facilitated by primer extension steps as shown in the figure in which chain termination nucleotides, digestion resistant nucleotides or nucleotides that allow retention of the cDNA product on an affinity matrix are differentially incorporated into the cDNA products of either the high or low affinity nucleic acids and the cDNA products are treated accordingly to amplification, enzymatic or chemical digestion or by contact with an affinity matrix.

Copolyorganosiloxanecarbonates are prepared by first preparing an oligomeric aromatic polycarbonate, such as an oligomeric bisphenol A polycarbonate, in the presence of a tertiary amine as the only catalyst species; contacting the oligomeric polycarbonate mixture with a polyorganosiloxane bis(aryl)chloroformate, such as the bischloroformate of hydroxy-terminated eugenol polydimethylsiloxane; and introducing phosgene and/or chain termination agent either continuously or in stages. A feature of the process is the presence of dihydroxyaromatic compound in only one charge, at the beginning. The products have excellent physical properties, including transparency.

The present invention provides methods of extending primer nucleic acids and sequencing target nucleic acids. The methods include the use of 2′-terminator nucleotides to effect chain termination. In addition to related reaction mixtures and kits, the invention also provides computers and computer readable media.

The invention relates to a method for preparing a low-temperature finalizing polyurethane elastic fiber, comprising the steps of carrying out condensation polymerization on polyether diol PTMG, polyester diol PE, diphenylmethane diisocyanate MDI and tetramethyl benzene dimethyl diisocyanate m-TMXDI to obtain a carbamic acid ester prepolymer, fully dissolving the prepolymer by taking DMAC (Dimethyl Acetamide) or DMF (Dimethyl Formamide) as the solvent, carrying out chain extension and chain termination on the prepolymer by using a chain extender and a chain terminator to obtain polyurethane urea solution, and finally adding various functional auxiliaries in the polyurethane urea solution and preparing to obtain the polyurethane elastic fiber with low-temperature finalizing performance via a dry spinning system.

The invention relates to an oxidization viscosity reducer for viscous oil recovery by steam injection and a preparation method thereof. The oxidization viscosity reducer comprises components by weight percentage: 0.5 to 10 percent of component A, 0.5 to 10 percent of component B, 0.1 to 8 percent of component C, 0.1 to 5 percent of component D, and the balance being water, wherein the component Ais peroxide, the component B is transition metal salt of an organic acid, the component C is inorganic salt with the acidity shown in a hydrolysate, and the component D is an alkaline substance. The oxidization viscosity reducer can oxidize gelatine and asphaltine in viscous oil, reduce the viscosity of crude oil by changing a structure of the viscous oil through chain termination, oxidize to generate an acid substance at the same time, ensure that the viscous oil becomes a substance with the effect of a surfactant by adding the alkaline substance, and also play a role in viscosity reduction.The experiments show that the viscosity reduction rate can reach 99.9 percent when the viscosity reducer reacts with the crude oil for 24 hours at the temperature of 100 DEG C. The viscosity reducer has higher viscosity reduction rate, is applicable to the viscosity reduction of oil well stratums with high steam injection temperature, and also has good effect under relatively lower temperature conditions.

The present invention is directed toward improving the efficiency of chain terminator incorporation by Family B archaeon DNA polymerases. Previously, the low efficiency of ddNTP, and more especially dye-labeled ddNTP, incorporation has limited the usefulness of this group of DNA polymerases in protocols requiring chain terminator incorporation.

The invention relates to heat accumulation and preservation polyurethane elastic fibers containing phase change microcapsules and a preparation method of the heat accumulation and preservation polyurethane elastic fibers. According to the heat accumulation and preservation fibers, the heat accumulation and preservation performance of polyurethane fibers can be improved by adding 0.5-5wt% of the phase change microcapsules into polyurethane elastic fibers. The preparation method specifically comprises the following steps: (1) preparing the phase change microcapsules with nuclear shell structures by adopting a suspension polymerization method; (2) performing condensation and polymerization by taking polyether diol and diisocyanate as synthetic monomers to form prepolymer, dissolving the prepolymer by adding a solvent, and adding mixed amine to perform chain extension reaction and chain termination reaction on the prepolymer to obtain a polyurethane urea solution; and (3) adding the prepared phase change microcapsules together with other auxiliary agents into the polyurethane urea solution, performing mixed curing, and treating a spinning stock solution subjected to curing by virtue of a dry spinning technology to prepare the heat accumulation and preservation polyurethane elastic fibers. The polyurethane elastic fibers prepared by the method provided by the invention contain a certain proportion of a phase change material, the fibers prepared by the method provided by the invention or textiles of the fibers have excellent heat accumulation and preservation performances.

The invention provides an amine composition which consists of diamine and monoamine in the molar ratio of (1.1-17.1):1. The invention further provides polyurethane resin and a preparation method thereof. The total amine value of the polyurethane resin is 1.20-20.0 mgKOH/g; the primary amine value is 8.7-38.8 percent of the total amine value; the secondary amine value is 5.6-82.6 of the total amine value; and the tertiary amine value is 8.7-55.6 percent of the total amine value. The preparation method comprises the following steps of: mixing high molecular dihydric alcohol with diisocyanate ester; adding a catalyst, and reacting at the temperature of 30-100 DEG C for 2-8 hours to obtain a dibasic alcohol polymer; reacting with a low molecular active hydrogen compound and a low molecular polyhydroxy compound; adding diamine which accounts for 0-70.6 percent of 100 percent by weight of diamine in the amine composition, and expanding a chain in an ester solvent; and adding the rest of diamine in the amine composition and all monoamine, and undergoing chain expansion and chain termination reactions in an ester and/or amine solvent to obtain polyurethane resin. The prepared polyurethane resin has the advantages of high physical and mechanical properties and high-temperature stewing resistance.

The invention relates to a preparation method of a rare earth aluminate polyurethane elastic fiber capable of emitting long afterglow. The method comprises several steps as follows: (1) fully reacting polyalcohol with diisocyanate and adding a solvent for fully dissolution to obtain a -NCO-terminated prepolymer polyurethane formate solution; (2) performing chain extension and chain termination on the prepolymer solution with a mixed amine solution to produce a polyurethane urea stock solution; (3) adding 10wt% of a rare earth aluminate luminescent material to a polyurethane urea solution for curing, and spinning the polyurethane elastic fiber from the polyurethane urea solution by the aid of a dry spinning system. The polyurethane elastic fiber prepared with an in-situ polymerization method can be excited by visible light or fluorescence to emit blue afterglow with the wavelength ranging from 450 nm to 500 nm and the strength of about 3 cd/m<2>, the fiber has the very lasting glowing effect, the service life of the afterglow is longer than 10 h, and the fiber is non-toxic and harmless and has no adverse effect on the environment and human bodies.

The invention relates to a preparation method of a porous easy-dyeing spandex. The method is as below: adding polytetramethylene ether glycol PTMG, and 4,4- diphenyl-methane-diisocyanate 4,4-MDI in a first reactor for thorough prepolymerization reaction, so as to obtain an -NCO terminated prepolymer PP; fully dissolving the prepolymer PP in a high-speed dissolving machine by using N,N-dimethylacetamide DMAC as a solvent, so as to obtain a solution PPs containing -NCO terminated prepolymer; conducting chain growth and chain termination on the PPs in a second reactor by using a mixed amine DMAC solution containing a diamine chain extender, a monoamine termination agent and alcohol amine, so as to prepare -OH terminated polyurea carbamate solution; then, adding an antioxidant, a lubricant, a matting agent, an ultraviolet absorbent and polyvinylpyrrolidone PVP, stirring and dispersing; and finally, conducting spinning tension, high temperature drying, oiling and winding formation on the polyurea carbamate solution containing additives with the help of a dry spinning system, so as to obtain the porous easy dyeing spandex.

The invention relates to a monte carlo molecular simulation research method for the kinetic process of polymerization reaction. The method comprises the step that the polymerization reaction simulation process is divided into two parts, namely, a systemic movement part and a polymerization reaction part; when in the polymerization reaction part, the occurrence probability of triggering, chain growth, chain transfer, chain termination and other elementary reactions are controlled through different reaction probability; when in the systemic movement part, a local-global concentration potential difference which shows the difference of the local concentration and the global concentration of components is introduced to determine the concentration distribution state of each unit component in the system, in order to realize the balanced distributing state of the component unit in the polymerization reaction process; the monte carlo energy criterion for controlling unit particle movement involves a chemical key part and a non-key part. The method is simple and efficient; the problem of non-uniform distribution of the component unit in the simulation system caused by the consumption of an initiator and a monomer under the polymerization reaction can be avoided, and the kinetic process of the experiment system can be really reflected by being compared with the traditional molecular simulation method.

The invention relates to a preparation method of a polyurethane elastic fiber with moisture absorption and moisture liberation performance. The method is as below: 1) successively conducting a prepolymerization reaction, a chain extension reaction and a chain termination reaction on raw materials of polytetramethylene ether glycol PTMG and diphenylmethane-4,4'diisocyanate 4,4'-MDI to obtain a polyurethane urea stoste; 2) grinding and dispersing a natural macromolecular fibroin powder in an organic solvent dimethylacetamide DMAC to obtain a fibroin suspension; 3) measuring and mixing the polyurethane urea stoste and fibroin suspension at the same time in a static mixer to form a spandex blended spinning solution; and 4) conducting spurting and filament stretching on the prepared spandex blended spinning solution by a dry method spinning system, and evaporating and drying the solvent, so as to obtain the polyurethane elastic fiber with moisture absorption and moisture liberation performance. Compared with conventional polyurethane elastic fiber, the product prepared by the invention has significantly improved moisture absorption and moisture liberation performance.

The invention discloses a silicon hybridization acrylate-cement composite grouting material and a preparation method thereof, and belongs to the technical field of new materials of municipal and construction projects. Inorganic binder cement and inorganic nanoparticles are introduced into an acrylate pre-polymer, a polymerization reaction is generated under the effects of a crosslinking agent, aninitiator and a promoter, and a mixture is polymerized to form a mesh complex hybridization gel body insoluble in water through the processes of chain initiation, chain growth and chain termination; siloxane modified acrylate can eliminate the difference between an organic material and an inorganic material (cement), improve the interaction between interfaces, and improve compatibility between polyacrylate resin and the cement; and the composite grouting material is less in environment pollution, does not generate dust pollution, belongs to an environment-friendly material, and can simultaneously solve the problems that an acrylate grouting material is low in strength, and a cement grouting material is poor in dry shrinkage resistance, durability and dispersion resistance.

The invention discloses a method for identifying the species of plants by using genes; it comprises the following steps: extracting the genome DNA of the plant sample to be tested; using the genome DNA of the plant sample to be tested as a template, using primers designed for the rbcL gene sequence and matK The primers designed for the gene sequence were amplified by PCR; the PCR amplified products were recovered to obtain the target DNA; the target DNA was sequenced using the Sanger dideoxy chain termination method; the sequencing results were compared with the sequences in the public database, according to Homology identifies the test plant to a genus or species. The present invention identifies the species of the plant from the molecular level, which is more accurate than the morphological identification; there is no too much requirement on the integrity of the plant form, as long as there is a little tissue of the plant itself, DNA can be extracted and identified by the present invention.

The invention provides a waterborne polyurethane resin emulsion which contains a hydroxyl-modified binary vinyl chloride-vinyl acetate copolymer resin, a polymer dihydric alcohol, diisocyanate, a hydrophilic chain extender, an organic fluororesin, a catalyst, a neutralizer, a chain terminating agent and an initiator. The invention also provides a preparation method of the above waterborne polyurethane resin emulsion, a two-component waterborne silver powder coating composition prepared by the same and a preparation method thereof. The two-component waterborne silver powder coating composition provided by the invention has the advantages of good silver powder arrangement, good chemical corrosion resistance and good hardness.

The invention discloses a chloroethylene suspension polymerization terminator and a preparation method and a use method thereof, belonging to a terminator used in a chloroethylene polymerization process. The chloroethylene suspension polymerization terminator is characterized by being an aqueous emulsion dispersion liquid and consisting of the following raw materials in parts by weight: 100 parts of deionized water, 2-30 parts of organic tin thermal stabilizer, 0.3-4.5 parts of polyvinyl alcohol I, 0-3.1 parts of polyvinyl alcohol II, 0.2-4.5 parts of cellulose ether and 0.1-3.5 parts of chain terminator, wherein the deionized water is industrial secondary desalted water; the alcoholysis degree of the polyvinyl alcohol I is between 75-85 percent; the alcoholysis degree of the polyvinyl alcohol II is between 50-60 percent; and the cellulose ether is methyl cellulose (MC), hydroxyethylmethylcellulose (HEC) or hydroxypropyl methyl cellulose (HPMC). The invention provides a chloroethylene suspension polymerization terminator which can be used for effectively terminating a chloroethylene polymerization reaction and remarkably improving the aging whiteness and heat resistance of polymerized resin, and the preparation method and the use method thereof.

The invention relates to a method for preparing ultraviolet aging resistant spandex through in situ polymerization. The method comprises the following steps: (1) dissolving a special uvioresistant absorbent to a dimethylacetamide solvent, and forming a stable dispersion liquid through stirring; (2) adding the dispersion liquid to oligomer polyol, mixing the oligomer polyol evenly, adding diisocyanate to prepare -NCO-capped carbamate prepolymer, and fully dissolving the carbamate prepolymer with the dimethylacetamide solvent to obtain a prepolymer solution; (3) carrying out chain expansion and chain termination reaction on the prepolymer by using the mixed amine solution to obtain a polyurethane-urea solution; (4) adding functional additives, such as an antioxidant, a delustering agent and a lubricating reeling agent to the polyurethane-urea solution, and stirring, mixing and storing the polyurethane-urea solution to prepare a polyurethane spinning solution; and (5) drawing and drying the prepared spinning solution by using a dry spinning system to obtain the ultraviolet aging resistant spandex.