Beijing University of Technology

China University of Geosciences (beijing)

Jiangsu Arit New Materials Co., Ltd.

Ziming Wang

Xiao Xi Liu

Shanshan Qian

Mingzhang Lan

Suping Cui

Yali Wang

Qian Xu

Guanghong Lai

Xiabing Bai

Jianan Guan

Yu Wang

Ming Zhao

Xiaoyu Ma

Jie Zhu

Jinbo Yang

Zhihua Luo

Peizhi Yu

Qianjin Mao

Hongxia Guo

Yuhong Wang

Xuesong Xing

Bairu Xia

A computer implemented method for recognizing an answer sheet includes the steps of: reading a filled answer sheet comprising at least one set of graphical codes; locating each set of graphical codes in the answer sheet; a set of graphical codes comprising one grid or two grids, wherein for each set of graphical codes, if the function mark of the first grid is filled, two sets or four sets of 8-digit binary codes are obtained according to the filling state of each of the filling areas in each grid of the set of graphical codes; and recognizing the corresponding characters according to the encoding format determined by the encoding format mark. If the function mark in the first grid is un-filled, the filling states of the eight icons of the encoding format mark are converted to the third set of binary codes for character recognition.

Computer implemented method for recognizing answer sheet

A method for preparing an accelerator for sprayed mortar/concrete is provided. The accelerator includes an organic component, inorganic component aluminum sulfate, an initiator, and a reductant. The organic component in the form of a polymer monomer is added to concrete and polymerized into a polymer network structure in the presence of the initiator and the reductant; and the inorganic component aluminum sulfate promotes rapid hydration of the concrete to form an inorganic network structure. Such organic-inorganic interpenetrating network thickens a cement-based material rapidly to achieve strong adhesion, fast-setting and hardening properties and effectively reduces resilience of the sprayed mortar/concrete. The accelerator prepared by the method is well compatible with all sorts of cement, efficient and environmentally friendly. The organic-inorganic interpenetrating network is formed by polymerization and cement hydration, and therefore, the toughness of the sprayed mortar/concrete is improved by the organic polymer-inorganic compound accelerator.

Method for preparing accelerator for sprayed mortar/concrete

A method for preparing comb structure temperature/pH-responsive polycarboxylic acid by end-group functionalization adopts temperature/pH-responsive monomer, unsaturated halogenated hydrocarbon, small monomer of carboxylic acid and other raw materials to prepare polycarboxylic acid material via self-polymerization, substitution and copolymerization. Temperature/pH-responsive monomers are first self-polymerized to obtain temperature/pH-responsive polymer chain with end-group functionalization, and then substitution with unsaturated halogenated hydrocarbons is conducted to obtain temperature/pH-responsive macromonomers with end-group functionalization, finally the obtained product is copolymerized with small carboxylic acid monomers to prepare comb structure polymer with polycarboxylic acid main chain and temperature/pH-responsive side chain.

End-group functionalized comb structure polycarboxylic acid and method for preparing the same

A preparation method of comb structure temperature/pH-responsive polycarboxylic acid adopts acrylic ester, temperature/pH-responsive monomer and other raw materials to obtain polycarboxylic acid via acrylate monomer self-polymerization, grafting with temperature/pH-responsive monomers and hydrolyzation. In other words, acrylate is used as the reaction monomer to polymerize polyacrylate with controllable molecular weight under the action of initiator and chain transfer agent, then the graft copolymers are copolymerized with temperature/pH-responsive monomers to obtain graft copolymers with acrylate polymers main chain and temperature/pH-responsive polymer side chains. Finally, the graft copolymer is hydrolyzed to obtain the comb structure temperature/pH-responsive polycarboxylic acid with polyacrylic acid main chain and temperature/pH-responsive monomer side chain.

Preparation method of temperature/pH-responsive polycarboxylic acid

A star-shaped polyacrylamide copolymer and a preparation method thereof are provided, as well as a drilling fluid containing the star-shaped polyacrylamide copolymer. Only the star-shaped polyacrylamide copolymer is added into the drilling fluid; under a high-temperature environment, the filtration volume of the drilling fluid can be reduced, the high-temperature rheological property of the drilling fluid is improved, and the pressure loss of a circulation system of the drilling fluid is reduced.

Star-shaped polyacrylamide copolymer and preparation method thereof and drilling fluid including the copolymer

This invention relates to a method for preparing a polycarboxylate superplasticizer by graft copolymerization of fatty acid vinyl ester onto acrylate polymer. In this invention, a type of polycarboxylate superplasticizer by graft copolymerization of fatty acid vinyl ester onto acrylate polymer was synthesized by the processes of polymerization-grafting-alcoholysis-hydrolysis with acrylate and fatty acid vinyl ester as main reactants. In the first polymerization step, the polyacrylate was synthesized by using acrylate as monomer and a certain amount of initiator and molecular weight regulator. In the second graft copolymerization step, the graft polymer with polyacrylate as main chain and poly(fatty acid vinyl ester) as side chain was synthesized by graft copolymerization between polyacrylate and fatty acid vinyl ester. The final polycarboxylate superplasticizer product with polyacrylic acid as main chain and polyvinyl alcohol as side chain was obtained by subsequent alcoholysis and hydrolysis steps. The preparation process of this invention exhibited some characteristics including simpleness, easy controlling, low cost, environmental friendliness and pollution free. The fatty acid vinyl ester was as a reactant instead of conventional polyethylene glycol macromonomer, which enriched the applicable scope of reactive raw materials. The prepared polycarboxylate superplasticizer showed good cement paste fluidity and fluidity retention, which manifested as good adaptability to cement and application performance in concrete.

Method for preparation of polycarboxylate superplasticizer by graft copolymerization of fatty acid vinyl ester onto acrylate polymer

This invention relates to a method for preparing a star-shaped polycarboxylate superplasticizer by the first esterification step with polyol and (meth)acrylic acid as main reactants and the second polymerization step. In the first step, the star-shaped polymerizable active ends were synthesized by esterification between polyol and (meth)acrylic acid in the presence of catalyst. In the second step, the final star-shaped polycarboxylate superplasticizer was prepared by radical polymerization among the product obtained in first step, unsaturated polyoxyethylene ethers, molecular weight regulator and unsaturated carboxylic acid in the presence of initiator. The production process of this invention exhibits some characteristics including simple, easily controllable, high polymerization degree, low cost and pollution free. The star-shaped molecular structure of polycarboxylate superplasticizer can be achieved through synthesizing active 'core' by esterification and 'arm' by radical polymerization. It showed better cement paste fluidity and fluidity retention, which manifested as better adaptability to cement and application performance in concrete, than both traditional linear and comb-shaped polycarboxylate superplasticizer at common or lower dosage.

Preparation method of high-performance star-shaped polycarboxylate superplasticizer

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Beijing, China

Ziming Wang