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molecular SIMULATION STUDY ON THE CHANGE OF polymer STRUCTURE DURING YIELDING

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chinese Journal of polymer science 2001年第5期19卷 527-529页

作者： Chen-guang xu Tai-ning Liang Juan Sun Xiao-zhen Yang state key {3. of polymer physics and chemistry center for molecular science, institute of chemistry chinese academy of sciences,{13. 中科院化学所高分子物理与化学国家重点实验室北京

A better understanding of a recently raised argument on whether there occurs a structure change during yielding has been acquired by using molecular simulation. That is, when monitoring the displacements of all atoms before and after the yield, a structure transition does occur, which is the 'atomic jump' that coordinates the amount of the atoms in the polymer and makes a large step beyond similar to0.05 nm for all those atoms. Results indicate that the complex of polymer chain packing induces the multiple atomic jumps around the yield point. This explains why polymers have a broader yielding peak.

关键词： polymer deformation yield structure transition atomic jump multiple yields

STUDY ON PYROLYSIS OF POLYPHENYLSILSESQUIOXANE

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chinese Journal of polymer science 2002年第6期20卷 573-577页

作者： Jun Ma Liang-he Shi jian-min Zhang Bai-yu Li De-yan Shen jian xu state key laboratory of polymer physics & chemistry center for molecular science, institute of {3.,chinese academy of sciences, beijing 100080 china center for molecular science Institute of Chemistry Chinese Academy of Sciences State Key Laboratory of Polymer Physics & Chemistry 北京 100080

X-ray photoelectron spectroscopy and Raman spectroscopy were' used to determine the chemical change of polyphenylsilsesquioxane (PPSQ) during pyrolysis in flowing nitrogen. Two temperature ranges were found for pyrolysed PPSQ below and above 600degreesC, respectively. The former is related to the rearrangement of PPSQ backbone and the latter reflects that most of backbone structure of PPSQ might be broken down and unorganized. Carbon formed in carbonization of PPSQ sample pyrolysed at 900degreesC should be sp(3. bonded carbon with crystallite size effects or defects.

关键词： pyrolysis polyphenylsilsesquioxane

STRESS-INDUCED CRYSTALLIZATION OF POLYURETHANE/MONTMORILLONITE NANOCOMPOSITE

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chinese Journal of polymer science 2002年第5期20卷 481-483页

作者： Xin-hua Dai Xiang-dong Luo Qun Gu Xiao-li Zhang De-yan Shen Liang-he Shi jian xu state {3. laboratory of polymer physics and Chemiscy center for molecular science, institute of chemistry,chinese academy of sciences, {13. 100080, china center for molecular science Institute of Chemistry Chinese Academy of Sciences State Key Laboratory of Polymer Physics and Chemistry 北京 100080

Exfoliated polyurethane/montmorillonite nanocomposites with both high elongation at break and high tensilestrength were studied by dynamic-infrared spectroscopy (dynamic-IR). The results show that crystallization indu... 详细信息

关键词： PU/montmorillonite nanocomposite dynamic-IR crystallization

A NOVEL METHOD FOR CHARACTERIZING THE WHOLE PROCESS OF polymer GELATION

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chinese Journal of polymer science 2001年第4期19卷 335-339页

作者： Qiang Chen Xian-min Zhang Guo-wei Wang jian xu state {3. laboratory of polymer physics & chemistry, center for molecular science, institute of chemistry, {13. beijing 100080, china Department of Information & Electronic Engineering Zhejiang University, Hangzhou 3.0027, china Tjanjin Polytechnic University,Tianjin 3.0160 中科院化学所高分子物理与化学国家重点实验室北京浙江大学浙江杭州

A novel method was established to investigate the gelation process of polymers. The change of refractive index of a polymer system during gelation was determined in situ in a prismatic cell. It can give reliable information on the whole gelation process. The apparatus and the execution of this technique are illustrated and the error is also discussed.

关键词： gelation process in situ technique refractive index

FABRICATION OF SELF-ASSEMBLY DNA-C_(60) MULTILAYER FILMS

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chinese Journal of polymer science 2002年第6期20卷 591-593页

作者： Shu-guang Yang Yong-jun Zhang Xin-hua Dai Wen-hong Tang Chun-yan Liu Wei-xiao Cao Yu-liang Li jian xu state {3. laboratory of polymer physics and chemistry, institute of chemistry, chinese academy of sciences,beijing 100080, {13. Technology institute of physics and chemistry chinese academy of sciences, beijing 100101, {13. College of chemistry and molecular Engineering Peking University beijing 100871, {13. institute of chemistry Chinese Academy of Sciences State Key Laboratory of Polymer Physics and Chemistry 北京 100080 Technology institute of physics and chemistry Chinese Academy of Sciences 北京 100101 College of chemistry and molecular Engineering Peking University 北京 100871

Electrostatic layer-by-layer self-assembly multilayer films were successfully fabricated from C-60-ethylenediamine adduct (C-60-EDA) and DNA. Under visible light irradiation, DNA is ready to be cleaved and the films a... 详细信息

关键词： self-assembly photo-induced cleavage DNA C-60

Characterization of the sequence distribution of poly （ethylene-co-vinyl acetate）with NMR spectroscopy

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Characterization of the sequence distribution of poly （ethy...

New sustainable polymers with on-demand depolymerization property

第四届全国高聚物分子表征学术讨论会

作者： Zhiqiang Su, Ying Zhao, Xiuqin Zhang, Shannong Zhu, Dujin Wang, Duanfu xu state key {3. of polymer physics and chemistry, Joint {3. of polymer science and Materials, center for molecular science, {13. of chemistry, chinese academy of sciences, beijing 100080, china

＜正＞ High-resolution NMR,either solution or solid-state spectra,can provideabundant structure information and has been paid more attention inrecent years, capable of elucidating not only the details of thechemical structure of a polymer,but also its dynamic *** help of high-resolution NMR techniques, the sequence distributionand condensed state of EVA copolymers can be clearly characterized,helping to further understand the structure-property correlations ofthe corresponding materials on a molecular level.

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来源： cnki会议评论

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cnki会议

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science china chemistry 2024年第9期67卷 2803-2841页

作者： Yangyang Sun Zesheng An Yanshan Gao Rongrong Hu Ye Liu Hua Lu Xiao-Bing Lu xuan Pang Anjun Qin Yong Shen Youhua Tao Yu-Zhong Wang Junpeng Wang Gang Wu Guang-Peng Wu Tie-Qi xu Xing-Hong Zhang Yuetao Zhang Zhenbiao Zhang jian-Bo Zhu Miao Hong Zhibo Li state key laboratory of Organometallic {3. Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China state key laboratory Base of Eco-Chemical Engineering College of Chemical EngineeringQingdao University of Science and TechnologyQingdao266042China state key laboratory of Supra{3. Structure and Materials College of ChemistryJilin UniversityChangchun 130012China state key laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Luminescence from Molecular AggregatesSouth China University of TechnologyGuangzhou 510640China state key laboratory of Fine Chemicals Frontiers Science Center for Smart MaterialsDalian University of TechnologyDalian 116024China beijing National laboratory for molecular {3. Center for Soft Matter Science and EngineeringKey Laboratory of Polymer Chemistry and Physics of Ministry of EducationCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China key laboratory of polymer Ecomaterials Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China The Collaborative Innovation center for Eco-Friendly and Fire-Safety polymeric Materials(MoE) National Engineering Laboratory of Eco-Friendly Polymeric Materials(Sichuan)College of ChemistryState Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu 610064China School of polymer science and polymer Engineering the University of AkronAkronOH 44325USA MOE key laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027China state and Local Joint Engineering laboratory for Novel Functional polymeric Materials Jiangsu Key Laboratory of Advanced Functional Polymer Design and ApplicationSuzhou Key Laboratory of Macromolecular Design and Precision SynthesisCollege of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China

To combat the crisis of today's synthetic polymers arising from unsustainable production and disposal,it is essential for the synthetic polymer community to reshape the current polymer industry with sustainable *** an emerging class of sustainable polymers,the development of chemically depolymerizable polymers(CDPs),which can undergo closed-loop depolymerization/repolymerization cycles to reproduce virgin polymers without the loss of properties from recovered monomers,offers an ideal solution to preserve finite natural resources,provides a feasible solution to the end-of-life issue of polymer waste,and thereby establishes a circular materials ***,two grand key challenges have been encountered in the establishment of practically useful CDPs:how to balance polymerization and depolymerization ability and how to unify conflicted depolymerizability and physical ***,this critical review article presents our vision for summarizing feasible strategies to overcome the above two significant challenges and the design principles for constructing an ideal CDP by highlighting selected major progress made in this rapidly expanding field.

关键词： chemically depolymerizable polymers sustainable polymers depolymerization monomer recovery degradation plastics

Compressive strain in Cu catalysts:Enhancing generation of C2+products in electrochemical CO_(2)reduction

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science Bulletin 2024年第18期69卷 2881-2891页

作者： Qikui Fan Pengxu Yan Fuzhu Liu Zhongshuang xu Pengfei Liang Xi Cao Chenliang Ye Moxuan Liu Lingyi Zhao Shan Ren Huanran Miao Xiai Zhang Zhimao Yang Xiangdong Ding {3. Yang Chuncai Kong Yuen Wu MOE key laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter Key Laboratory for Advanced Materials and Mesoscopic Physics of Shaanxi ProvinceSchool of PhysicsXi’an Jiaotong UniversityXi’an 710049China state key laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China College of chemistry and Materials science Anhui Normal UniversityWuhu 241002China Department of Power Engineering North China Electric Power UniversityBeijing 102206China College of chemistry and Chemical Engineering Xi’an University of Science and TechnologyXi’an 710054China center for Materials and Interfaces Shenzhen Institutes of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China Hefei National laboratory for Physical sciences at the Microscale Collaborative Innovation Center of Chemistry for Energy Materials(iChEM)School of Chemistry and Materials Scienceand National Synchrotron Radiation LaboratoryUniversity of Science and Technology of ChinaHefei 230026China

Elastic strain in Cu catalysts enhances their selectivity for the electrochemical CO_(2)reduction reaction(eCO_(2)RR),particularly toward the formation of multicarbon(C_(2+))***,the reasons for this selectivity and the effect of catalyst precursors have not yet been ***,we employed a redox strategy to induce strain on the surface of Cu *** transformation was employed to convert Cu nanocrystals to CuxO nanocrystals;these were subsequently electrochemically reduced to form Cu catalysts,while maintaining their compressive *** a flow cell configuration,a current density of 1 A/cm^(2)and Faradaic efficiency exceeding 80%were realized for the C_(2+)*** selectivity ratio of C_(2+)/C1 was also remarkable at 9.9,surpassing that observed for the Cu catalyst under tensile strain by approximately 7.6 ***-situ Raman and infrared spectroscopy revealed a decrease in the coverage of K+ion-hydrated water(K·H_(2)O)on the compressively strained Cu catalysts,consistent with molecular dynamics simulations and density functional theory *** element method simulations confirmed that reducing the coverage of coordinated K·H_(2)O water increased the probability of intermediate reactants interacting with the surface,thereby promoting efficient C–C coupling and enhancing the yield of C_(2+)*** findings provide valuable insights into targeted design strategies for Cu catalysts used in the eCO_(2)RR.

关键词： Strain effect CO_(2)electroreduction to C^(2+) Catalytic selectivity Copper catalyst Water coverage

Blocking the PD-1 signal transduction by occupying the phosphorylated ITSM recognition site of SHP-2

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science china Life sciences 2024年

作者： Wenjie Li Wenyi Mei Hewei jiang Jie Wang Xiaoli Li Lina Quan Yanyan Diao Yanni Ma Sisi Fan Zhuwei Xie Mengdie Gong Huan Zhu Dewen Bi Feng Zhang Lei Ma jian Zhang Yufeng Gao Aris Paschalidis Honghuang Lin Fangfang Liu Kangdong Liu Mingliang Ye Zhenjiang Zhao Yajun Duan Zhuo Chen Yufang {3. Weilie Xiao Shengce Tao Lili Zhu Honglin Li Innovation center for AI and Drug Discovery East China Normal University Shanghai key laboratory of New Drug Design School of PharmacyEast China University of Science&Technology Shanghai center for Systems Biomedicine Key Laboratory of Systems Biomedicine (Ministry of Education)Shanghai Jiao Tong University Lingang laboratory key laboratory of Medicinal chemistry for Natural Resource Ministry of EducationYunnan Characteristic Plant Extraction LaboratoryYunnan Provincial Center for Research&Development of Natural ProductsState Key Laboratory for Conservation and Utilization of Bio-Resources in YunnanSchool of Pharmacy and School of Chemical Science and TechnologyYunnan University CAS key laboratory of Separation sciences for Analytical {3. National Chromatographic R&A CenterDalian Institute of Chemical PhysicsChinese Academy of Sciences Department of Cardiology The First Affiliated Hospital of USTCDivision of Life Sciences and MedicineUniversity of Science and Technology of China Department of Infectious Diseases The First Affiliated Hospital of Anhui Medical University Department of Medicine University of Massachusetts Chan Medical School Department of Pathophysiology School of Basic Medical SciencesAcademy of Medical ScienceCollege of MedicineZhengzhou University

Targeting the PD-1/PD-L1 axis with small-molecular inhibitors is a promising approach for immunotherapy. Here, we identify a natural pentacyclic triterpenoid, Pygenic Acid A(PA), as a PD-1 signaling inhibitor. PA exerts anti-tumor activity in hPD-1 knock-in C57BL/6 mice and enhances effector functions of T cells to promote immune responses by disrupting the PD-1 signaling transduction. Furthermore, we identify SHP-2 as the direct molecular target of PA for inhibiting the PD-1 signaling transduction. Subsequently, mechanistic studies suggest that PA binds to a new druggable site in the phosphorylated PD-1 ITSM recognition site of SHP-2, inhibiting the recruitment of SHP-2 by PD-1. Taken together, our findings demonstrate that PA has a potential application in cancer immunotherapy and occupying the phosphorylated ITSM recognition site of SHP-2 may serve as an alternative strategy to develop PD-1 signaling inhibitors. In addition, our success in target recognition provides a paradigm of target identification and confirmation for natural products.

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