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RAFT Miniemulsion Polymerization of MMA with Cumyl Dithiobenzoate as Chain Transfer Agent

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Chinese Chemical Letters 2006年第9期17卷 1247-1250页

作者： Tian Ying GUO Dong Lin TANG Jing Wei ZHU mou dao song Bang Hua ZHANG Key Laboratory of Functional Polymer Materials Ministry of Education Institute of Polymer Chemistry Nankai University Tianjin 300071

Reversible addition-fragmentation transfer （RAPT） miniemulsion polymerizations for PMMA with cumyl dithiobenzoate （CDB） as a chain transfer agent （CTA） has been carried out. Higher temperature made the polymeriz... 详细信息

关键词： RAFT polymerization miniemulsion chain transfer agent cumyl dithiobenzoate.

SYNTHESIS AND CHARACTERIZATION OF POLYURETHANE LATEX

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Chinese Chemical Letters 1996年第4期7卷 375-376页

作者： Qing Ye ZHOU Han LI mou dao song Bang Hua ZHANG Bing Lin HE(Institute of Polymer Chemistry, Nankai University, Tianjin 300071) Institute of Polymer Chemistry Nankai University Tianjin 300071

A method of preparing stable, film-forming polyurethane latices without the use of emulsifying agents is described in this article. The reaction of polypropylene glycol with a stoichiometric ratio(NCO:OH=2:1) of tolylene-diisocyanate in the presence of ketones and catalyst produces an isocyanate terminated prepolymer. Then addition of diethylene glycol as chain extender to prepolymer solution can yield a relatively high molecular weight poly(urethane-ether) which is readily dispersed with aqueous tartaric acid after tartaric acid and water diffuse into the suspended globules of the latex and produces the chain extended urethane. A linear or crosslinked high molecular weight self-emulsifiable polyurethane carl be obtained due to the reaction of the hydroxy group of tartaric acid and little water with isocyanate endgroups. The results of FTIR also show that an expected polyurethane emulsion has been successfully synthesized.

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Semibatch Emulsifier-free Emulsion Copolymerization of Methyl Methacrylate and n-Butyl Acrylate in the Presence of 2-Hydroxyethyl Methacrylate

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Chinese Chemical Letters 1998年第7期9卷 683-686页

作者： Tian Ying GUO mou dao song Qing Ye ZHOU Bang Hua ZHANG Jian Biao MA Bing Lin HE (The State key Laboratory of Functional Polymer Materials for Adsorption and Separation,Institute of Polymer Chendstry, Nankai University, Tianin, 300071) State Key Lab. Funct. Poly. M.A.S. Institute of Polymer Chemistry Nankai University Tianjin 300071 China

The semibatch emulsifier-free emulsion copolymerization of methyl methacrylate (MMA) and n-butyl acrylate (BA) in the presence of 2-hydroxyethyl methacrylate (HEMA) initiated by K2S2O8 (PSP) was studied. The average particle diameter increases with an increase of total solids content, HEMA content, PSP content, ionic strength of the system and monomer feed rate, and decreases with the monomer feed ratio from 3/1 (MMA/BA mole.) to 1/3. The stability of this reaction system is improved by adding HEMA as nonionic comonomer. The high solids content (50%) latex with monodisperse particle can be obtained using this process.

关键词： emulsion copolymerization semibatch emulsifier-free MMA and BA latex stability

Distribution and geochemical significance of alkylbenzenes for crude oil with different depositional environments and thermal maturities

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Petroleum Science 2024年第2期21卷 777-790页

作者： Bing-Kun Meng dao-Fu song Yuan Chen Sheng-Bao Shi School of Petroleum Engineering and Environmental Engineering Yan'an UniversityYan'an716000ShaanxiChina State Key Laboratory of Petroleum Resources and Prospecting College of GeosciencesChina University of PetroleumBeijing102249China

A total of 45 alkylbenzenes were detected and identified in crude oils with different depositional environments and thermal maturities from the Tarim Basin,Beibuwan Basin,and songliao Basin using comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry(GC×GCTOFMS).By analyzing the distribution characteristics of C0-C5alkylbenzenes,it is found that the content of some alkylbenzenes varies greatly in crude *** on the distribution characteristics of 1,2,4,5-tetramethylbenzene(Te MB)and 1,2,3,4-Te MB,the ratio of 1,2,4,5-Te MB to 1,2,3,4-Te MB is proposed to indicate the organic matter origin and depositional environment of ancient *** samples originated mainly from lower hydrobiont,algae,bacteria and source rocks deposited under reducing/anoxic conditions have low 1,2,4,5-/1,2,3,4-Te MB values(less than 0.6),while oil samples originated mainly from terrestrial higher plants and source rocks deposited under oxic/sub-oxic conditions have higher 1,2,4,5-/1,2,3,4-Te MB values(greater than 1.0).The significant difference of 1,2,4,5-/1,2,3,4-Te MB values is controlled by 1,2,4,5-Te MB content.1,2,4,5-Te MB content in oils derived from source rocks deposited in oxidized sedimentary environment(greater than 1.0 mg/g whole oil)is higher than that in oils from source rocks deposited in reduced sedimentary environment(less than 1.0 mg/g whole oil).1,2,4,5-/1,2,3,4-Te MB ratio might not or slightly be affected by evaporative fractionation,biodegradation and thermal maturity.1,2,4,5-/1,2,3,4-Te MB ratio and 1,2,4,5-Te MB content can be used as supplementary parameter for the identification of sedimentary environment and organic matter *** should be noted that compared to the identification of organic matter sources,the 1,2,4,5-/1,2,3,4-Te MB parameter is more effective in identifying sedimentary environments.

关键词： 1 2 4 5-Tetramethylbenzene GC×GC-TOFMS Organic matter origin Depositional environment

Co/carbon nanofiber with adjustable size and content of Co nanoparticles for tunable microwave absorption and thermal conductivity

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Journal of Materiomics 2024年第1期10卷 124-133页

作者： Shaohua Shi Pengpeng mou dao Wang Xiangying Li Shengjie Teng Maofan Zhou Xiaolong Yu Zhen Deng Gengping Wan Guizhen Wang State Key Laboratory of Marine Resource Utilization in South China Sea School of Materials Science and EngineeringHainan UniversityHaikouHainan570228China Department of Radiology Central South University Xiangya School of Medicine Affiliated Haikou HospitalHaikou570208China College of Science Qiongtai Normal UniversityHaikouHainan571127China Sanya Nanfan Research Institute of Hainan University Hainan Yazhou Bay Seed LaboratorySanya572025China

Electromagnetic pollution and heat dissipation problems are becoming increasingly worthy of attention due to the rapid development of electronic devices,which puts forward an urgent demand for microwave absorbers with excellent thermal management ***,high-performance Co/carbon nanofiber(Co/CNF)microwave absorbers with high thermal conductivity were fabricated by facile step-by-step *** microwave absorption properties can be readily tuned by adjusting the content and size of Co nanoparticles through concentration gradient *** from the formation of dielectric and magnetic coupling network,Co/CNF composites possess intensive dipole polarization,interface polarization,and magnetic *** optimal Co/CNF composites exhibit outstanding microwave absorption performance with a minimum reflection loss(RL)of−53.0 dB at 11.44 GHz,and a maximum effective absorption bandwidth(EAB)of 5.5 *** addition,the thermal conductivities of the Co/CNF-natural rubber(Co/CNF-NR)composites are significantly *** work may inspire the exploration of high-efficiency heat-conduction microwave absorbers based on CNF.

关键词： Carbon nanofiber Co nanoparticle Microwave absorption Heat conductivity

Gut microbiota-dependent phenylacetylglutamine in cardiovascular disease:current knowledge and new insights

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Frontiers of Medicine 2024年第1期18卷 31-45页

作者： Yaonan song Haoran Wei Zhitong Zhou Huiqing Wang Weijian Hang Junfang Wu dao Wen Wang Division of Cardiology Department of Internal MedicineTongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan430030China Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders Wuhan430030China

Phenylacetylglutamine(PAGln)is an amino acid derivate that comes from the amino acid *** are increasing studies showing that the level of PAGln is associated with the risk of different cardiovascular *** this review,we discussed the metabolic pathway of PAGln production and the quantitative measurement methods of *** summarized the epidemiological evidence to show the role of PAGln in diagnostic and prognostic value in several cardiovascular diseases,such as heart failure,coronary heart disease/atherosclerosis,and cardiac *** underlying mechanism of PAGln is now considered to be related to the thrombotic potential of platelets via adrenergic ***,other possible mechanisms such as inflammatory response and oxidative stress could also be induced by ***,since PAGln is produced across different organs including the intestine,liver,and kidney,the cross-talk among multiple organs focused on the function of this uremic toxic ***,the prognostic value of PAGln compared to the classical biomarker was discussed and we also highlighted important gaps in knowledge and areas requiring future investigation of PAGln in cardiovascular diseases.

关键词： PAGln cardiovascular disease gut microbiota uremic metabolite biomarker

High Speed Sintering:Assessing the Influence of Energy Input on Microstructure and Mechanical Properties of Polyether Block Amide(PEBA)Parts

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Chinese Journal of Polymer Science 2024年第5期42卷 675-682,I0004,I0010页

作者： Jiang-Tao Sun Zhi-Yong Fan Yi-Wei Mao Wei Li Wei Zhu dao-Sheng Cai Qing-song Wei State Key Laboratory of Materials Processing and Die&mould Technology Huazhong University of Science and TechnologyWuhan430074China State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan430074China National Engineering Research Centre for High Efficiency Grinding Hunan UniversityChangsha410082China Wuhan EasyMFG Technology CO. LTDWuhan430074China

High speed sintering,a new powder-bed fusion additive manufacturing technology,utilizes infrared lights(IR)to intensely heat and melt polymer *** presence of defects such as porosity,which is associated with particle coalescence,is highly dependdent on the level of energy *** study investigate the influcence of energy input on porosity and its subsequent effects on the mechanical properties and microstructures of PEBA *** parts were manufactured with a variety of lamp powers,resulting in a range of energy input levels spanning from low to ***,they underwent testing using Archimedes’method,followed by tensile *** porosity,mechanical characteristics,and energy input exhibit a strong correlation;inadequate energy input was the primary cause of pore *** the reduced IR light power resulted in the following outcomes:porosity,ultimate tensile strength,and elongation of 1.37%,7.6 MPa,and 194.2%,*** the energy input was further increased,the porosity was reduced to as low as 0.05%and the ultimate tensile strength and elongation were increased to their peak values of 233.8%and 9.1 MPa,respectively.

关键词： High speed sintering Additive manufacturing Energy input Powder bed fusion PEBA

High-static-low-dynamic stiffness isolator based on an electromagnetic negative stiffness spring with long linear stroke

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Science China(Technological Sciences) 2024年第3期67卷 740-752页

作者： YUAN ShuJin WU YaJun song DaiPing PU HuaYan mou LiSheng HOU Lei ZHAO JingLei LI XuePing LUO Jun WU Jie HUANG XiaoXu State Key Laboratory of Mechanical Transmissions Chongqing UniversityChongqing 400044China China Aerodynamics Research and Development Center Mianyang 621000China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China

Negative stiffness mechanisms can improve low-frequency vibration isolation performance and have been widely used in the vibration isolation of precision equipment. However, the negative stiffness mechanism usually introduces a nonlinear stiffness,resulting in a nonlinear response and worsening the vibration isolation performance, especially under large amplitude *** this paper, an electromagnetic spring with linear negative stiffness(ESLNS) is proposed, in which the antagonistic ampere forces of the energized coils are used to generate negative stiffness within a long linear stroke. The magnetic field distribution is improved through the design of the magnetic circuit, thereby increasing the stiffness generation efficiency. The stiffness can be adjusted bidirectionally by current within the range of positive and negative stiffness. An electromagnetic stiffness model was established based on the equivalent magnetic circuit method. Experimental measurements verified the accuracy of the model and proved the linearity of the electromagnetic spring. A vibration isolator with high static and low dynamic stiffness(HSLDS) based on the ESLNS is designed and tested. The experimental results prove that the introduction of the ESLNS can effectively expand the isolation frequency band without changing the equilibrium position. Moreover, the vibration isolator with ESLNS does not produce nonlinear response. The proposed electromagnetic spring with linear negative stiffness extends the application range of HSLDS isolators to a large amplitude vibration environment.

关键词： linear negative stiffness mechanism low-frequency vibration isolation electromagnetic spring vibration control

Pseudomonas aeruginosa regulator PvrA binds simultaneously to multiple pseudo-palindromic sites for efficient transcription activation

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Science China(Life Sciences) 2024年第5期67卷 900-912页

作者： Yibo Zhu Bingnan Luo Xingyu mou Yingjie song Yonghong Zhou Yongbo Luo Bo Sun Youfu Luo Hong Tang Zhaoming Su Rui Bao Center of Infectious Diseases Division of Infectious Diseases in State Key Laboratory of BiotherapyWest China HospitalSichuan UniversityChengdu 610041China Department of Geriatrics and National Clinical Research Center for Geriatrics West China HospitalSichuan UniversityChengdu 610041China Key Laboratory of Biodiversity and Environment on the Qinghai-Tibetan Plateau Ministry of EducationSchool of Ecology and EnvironmentTibet UniversityLhasa 850000China Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201210China College of Life Science Sichuan Normal UniversityChengdu 610101China Accurate Biotechnology(Hunan)Co. LtdChangsha 410006China

Tetracycline repressor(TetR)family regulators(TFRs)are the largest group of DNA-binding transcription factors and are widely distributed in bacteria and *** play vital roles in controlling the expression of various genes and regulating diverse physiological ***,a TFR protein Pseudomonas virulence regulator A(PvrA),was identified from Pseudomonas aeruginosa as the transcriptional activator of genes involved in fatty acid utilization and bacterial ***,we show that PvrA can simultaneously bind to multiple pseudo-palindromic sites and upregulate the expression levels of target ***-electron microscopy(cryo-EM)analysis indicates the simultaneous DNA recognition mechanism of PvrA and suggests that the bound DNA fragments consist of a distorted B-DNA double *** crystal structure and functional analysis of PvrA reveal a hinge region that secures the correct domain motion for recognition of the promiscuous ***,our results showed that mutations disrupting the regulatory hinge region have differential effects on biofilm formation and pyocyanin biosynthesis,resulting in attenuated bacterial ***,these findings will improve the understanding of the relationship between the structure and function of the TetR family and provide new insights into the mechanism of regulation of *** virulence.

关键词： Pseudomonas aeruginosa transcription regulator TetR protein-structure virulence