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A Study on the Impact of Chemical Structure on the Evolution of Aggregate Structure in Fiber-shaped High Density Polyethylene Vitrimer

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Chinese Journal of polymer science 2024年第10期42卷 1557-1565,I0013页

作者： Bing Wang Yuan-Chu Gao Hai Wang Hui Niu State Key Laboratory of Fine Chemicals School of Chemical EngineeringDalian University of TechnologyDalian116024China

Vitrimers have emerged as a prominent research area in the field of polymer *** of the studies have focused on synthesizing polymers with versatile dynamic crosslinking structures,while the impact of chemical structure on aggregate structure of vitrimers,particularly during polymer processing,remains insufficiently *** present study employed commercial maleic anhydride-grafted-high density polyethylene(M-g-HDPE)as the matrix and hexanediol as the crosslinker to facilely obtain fiber-shaped HDPE vitrimers through a reaction extrusion and post-drawing *** chemical structure characterization,morphology observation,thermal and mechanical properties investigation,as well as aggregate structure analysis,this work revealed the influence of dynamic bonds on the formation of aggregate structures during fiber-shaped vitrimers processing.A small amount of dynamic bonds in HDPE restricts the motion of PE chain during melt-extruding and post-drawing,resulting in a lower orientation of the PE ***,lamellar growth and fibril formation during post-drawing at high temperature are enhanced to some extent due to the competition between dynamic bond and chain *** uneven morphology of fibershaped HDPE vitrimers can be attributed to the stronger elastic effect brought by dynamic bonding,which plays a more dominant role in determining the mechanical properties of fiber-shaped vitrimers compared to aggregate *** Vitrimers have emerged as a prominent research area in the field of polymer *** of the studies have focused on synthesizing polymers with versatile dynamic crosslinking structures,while the impact of chemical structure on aggregate structure of vitrimers,particularly during polymer processing,remains insufficiently *** present study employed commercial maleic anhydride-grafted-high density polyethylene(M-g-HDPE)as the matrix and hexanediol as the crosslinker to facilely obtain fiber-shap

关键词： High density polyethylene vitrimer Fiber-shaped Aggregate structures Transesterification reaction

Recent progress on mechanisms,principles,and strategies for high-activity and high-stability non-PGM fuel cell catalyst design

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Carbon Energy 2024年第5期6卷 25-52页

作者： Yuping Yuan Yun Zheng Dan Luo Weibin Qiu Jiantao Wang Xin Wang Zhongwei Chen GRINM(Guangdong)Institute of New Materials Technology FoshanChina Department of Chemical Engineering Waterloo Institute for NanotechnologyWaterloo Institute for Sustainable EnergyUniversity of WaterlooWaterlooOntarioCanada Guangdong Provincial Key Laboratory of Nanophotonic Functional Materials and Devices School of Information and Optoelectronic Science and EngineeringSouth China Normal UniversityGuangdongChina National Power Battery Innovation Center GRINM Group Co.Ltd.BeijingChina

The commercialization of a polymer membrane H2-O2 fuel cell and its widespread use call for the development of cost-effective oxygen reduction reaction(ORR)nonplatinum group metal(NPGM)***,to meet the requests for the real-world fuel cell application and replacing platinum catalysts,it still needs to address some challenges for NPGM catalysts regarding the sluggish ORR kinetics in the cathode and their poor durability in acidic *** response to these issues,numerous efforts have been made to study NPGM catalysts both theoretically and experimentally,developed these into the atomically dispersed coordinated metal-nitrogen-carbon(M-N-C)form over the past *** this review,we present a comprehensive summary of recent advancements on NPGM catalysts with high activity and *** design strategies in terms of optimizing active-site density and enhancing catalyst stability against demetalization and carbon corrosion are *** is also emphasized the importance of understanding the mechanisms and principles behind those strategies through a combination of theoretical modeling and experimental ***,further understanding the mechanisms related to the active-site structure and the formation process of the single-atom active site under pyrolysis conditions is critical for active-site *** the active-site distance is the basic principle for improving catalyst activity through increasing the catalyst active-site *** studies for the catalyst deactivation mechanism and modeling stable active-site structures provide both mechanisms and principles to improve the NPGM catalyst ***,currently remained challenges and perspectives in the future on designing high-performance atomically dispersed NPGM catalysts toward fuel cell application are discussed.

关键词： batteries electrocatalysis energy storage and conversion fuel cells

Regulation of specific abnormal calcium signals in the hippocampal CA1 and primary cortex M1 alleviates the progression of temporal lobe epilepsy

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Neural Regeneration Research 2024年第2期19卷 425-433页

作者： Feng Chen Xi Dong Zhenhuan Wang Tongrui Wu Liangpeng Wei Yuanyuan Li Kai Zhang Zengguang Ma Chao Tian Jing Li Jingyu Zhao Wei Zhang Aili Liu Hui Shen Laboratory of Neurobiology School of Biomedical EngineeringTianjin Medical UniversityTianjinChina Institute for Translational Neuroscience the Second Affiliated Hospital of Nantong UniversityNantongJiangsu ProvinceChina Institute for Translational Brain Research Fudan UniversityShanghaiChina Department of Radiology the Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjingJiangsu ProvinceChina Innovative Institute of Chinese Medicine and Pharmacy Shandong University of Traditional Chinese MedicineJinanChina Department of Anesthesiology Tianjin Medical University General HospitalTianjinChina Department of Orthopaedics Tianjin Medical University General HospitalTianjinChina Tianjin Eye Hospital Tianjin Eye InstituteTianjin Key Lab of Ophthalmology and Visual ScienceTianjinChina Laboratory of Neurobiology School of Basic Medical SciencesTianjin Medical UniversityTianjinChina

Temporal lobe epilepsy is a multifactorial neurological dysfunction syndrome that is refractory,resistant to antiepileptic drugs,and has a high recurrence *** pathogenesis of temporal lobe epilepsy is complex and is not fully *** calcium dynamics have been implicated in temporal lobe ***,the effect of fluctuating calcium activity in CA1 pyramidal neurons on temporal lobe epilepsy is unknown,and no longitudinal studies have investigated calcium activity in pyramidal neurons in the hippocampal CA1 and primary motor cortex M1 of freely moving *** this study,we used a multichannel fiber photometry system to continuously record calcium signals in CA1 and M1 during the temporal lobe epilepsy *** found that calcium signals varied according to the grade of temporal lobe epilepsy *** particular,cortical spreading depression,which has recently been frequently used to represent the continuously and substantially increased calcium signals,was found to correspond to complex and severe behavioral characteristics of temporal lobe epilepsy ranging from gradeⅡto gradeⅤ.However,vigorous calcium oscillations and highly synchronized calcium signals in CA1 and M1 were strongly related to convulsive motor *** inhibition of pyramidal neurons in CA1 significantly attenuated the amplitudes of the calcium signals corresponding to gradeⅠ*** addition,the latency of cortical spreading depression was prolonged,and the above-mentioned abnormal calcium signals in CA1 and M1 were also significantly ***,it was possible to rescue the altered intracellular calcium *** simultaneous analysis of calcium signals and epileptic behaviors,we found that the progression of temporal lobe epilepsy was alleviated when specific calcium signals were reduced,and that the end-point behaviors of temporal lobe epilepsy were *** results indicate that the calcium dynamic between CA1 and M1 may reflect sp

关键词： Ca^(2+) calcium signals chemogenetic methods hippocampus primary motor cortex pyramidal neurons temporal lobe epilepsy

Bulk heterojunction perovskite solar cells incorporated with solution-processed TiOx nanoparticles as the electron acceptors

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Chinese Chemical Letters 2020年第9期31卷 2249-2253页

作者： Tao Zhu Yongrui Yang Suyuan Zhou Xiang Yao Lei Liu Wenping Hu Xiong Gong Department of polymer Engineering College of Polymer Science and Polymer EngineeringThe University of AkronAkronOH 44325United States Institute of Molecular Plus Tianjin Key Laboratory of Molecular Optoelectronic SciencesSchool of ScienceTianjin University and Collaborative Innovation Centre of Chemical Science and EngineeringTianjin 300072China

In the past ten years,perovskite solar cells were rapidly developed,but the intrinsic unbalanced charge carrier diffusion lengths within perovskite materials were not fully addressed by either a planar heterojunction or meso-superstructured perovskite solar *** this study,we report bulk heterojunction perovskite solar cells,where perovskite materials CH3NH3PbI3 is blended with solution-processed n-type TiOx nanoparticles as the photoactive *** indicate that one-step solution-processed CH3NH3PbI3:TiOx bulk-heterojunction thin film possesses enhanced and balanced charge carrier mobilities,superior film morphology with enlarged crystal sizes,and suppressed trapinduced charge ***,bulk heterojunction perovskite solar cells by CH3NH3PbI3 mixed with 5 wt% of TiOx,which is processed by one-step method rather than typical two-step method,show a short-circuit current density of 20.93 mA/cm2,an open-circuit voltage of 0.90 V,a fill factor of 80% and with a corresponding power conversion efficiency of 14.91%,which is more than 30% enhancement as compared with that of perovskite solar cells with a planar heterojunction device ***,bulk heterojunction perovskite solar cells possess enhanced device *** these results demonstrate that perovskite solar cells with a bulk heterojunction device structure are one of apparent approaches to boost device performance.

关键词： Bulk heterojunction Perovskite TiO_x Balanced mobilities Stability

Artificial stepwise light harvesting system in water constructed by quadruple hydrogen bonding supramolecular polymeric nanoparticles

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Chinese Chemical Letters 2024年第2期35卷 370-373页

作者： Tangxin Xiao Xiuxiu Li Liangliang Zhang Kai Diao Zheng-Yi Li Xiao-Qiang Sun Leyong Wang Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology School of Petrochemical EngineeringChangzhou UniversityChangzhou 213164China Jiangsu Key Laboratory of Advanced Organic Materials School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China

Stepwise energy transfer is ubiquitous in natural photosynthesis,which greatly promotes the widespread use of solar ***,we constructed a supramolecular light harvesting system based on sequential energy transfer through the hierarchical self-assembly of M,which contains a cyanostilbene core flanked by two ureidopyrimidinone motifs,endowing itself with both aggregation-induced emission behavior and quadruple hydrogen bonding *** monomer M can self-assemble into hydrogen bonded polymers and then form supramolecular polymeric nanoparticles in water through a mini-emulsion *** nanoparticles were further utilized to encapsulate the relay acceptor ESY and the final acceptor NDI to form a two-step FRET *** fluorescence including a white-light emission was successfully *** work not only shows a desirable way for the fabrication of efficient two-step light harvesting systems,but also shows great potential in tunable photoluminescent nanomaterials.

关键词： Light harvesting system Supramolecular polymer Quadruple hydrogen bonding AIE Self-assembly

SYNTHESIS,CHARACTERIZATION AND ENHANCED ELECTRICAL PROPERTIES OF CTAB-DIRECTED POLYANILINE NANOPARTICLES

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Chinese Journal of polymer science 2011年第2期29卷 181-190页

作者： Lal Said Jan Mohamed Ahmed Siddig Department of Physics Postgraduate College Mardan23200Khyber PakhtunkhwaPakistan school of Physics and Applied Physics Faculty of Science and TechnologyEL Neelain UniversityKhartoumSudan

Inverse microemulsion system of cetyltrimethylammonium bromide（CTAB） molecules is utilized for virtually monodispersed and controlled growth of HCl polyaniline（PANI） nanoparticles at room temperature（ca.300 K）.The templated electroconductive polymer reveals lamellar crystalline structure under X-ray diffraction signifying marked sub-chain alignment of the polymerized *** nanostructured polymer has spherically symmetric morphology in a size range of 2.0 nm to 6.0 nm under electron microscope *** permeation chromatography gives polydispersity index of 1.02 for nanostructured polymer in agreement with the size monodispersity transpired by electron *** *** conductivityσ_（dc） of PANI at room temperature is 10.11 S/cm whereas the variation of conductivity with temperature in the range 227-303 *** that the conducting mechanism can be considered as three-dimensional variable-range-hopping（3D-VRH）.UV-Vis spectrum indicates two broad absorption bands due to polaron formation that contributes to enhanced electrical conductivity of the *** fundamental absorption edge in the polymer is formed by direct allowed transitions to the extent that the optical band gap value was found to be 2.35 *** crystalline nanostructure and homogeneous doping attained in the cationic template of amphiphile are argued as contributing factors to the enhanced conductivity of the polymer.

关键词： Polyaniline Nanostructured Band gap energy Electrical conductivity

PRELIMINARY INVESTIGATION ON THE MISCIBILITY OF ISOTACTIC POLYPROPYLENE (iPP) AND SYNDIOTACTIC POLYPROPYLENE (sPP) BLENDS

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Chinese Journal of polymer science 2006年第6期24卷 569-573页

作者： Chun-xiao Zheng Xiu-qin Zhang Joerg Rottstegge Xia Dong Ying Zhao Du-jin Wang Shan-nong Zhu Zhi-gang Wang Charles C. Han Duan-fu Xu Key Laboratory of Engineering Plastics Joint Laboratory of Polymer Science and Materials Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China State Key Laboratory of polymer Physics and Chemistry Joint Laboratory of Polymer Science and Materials Institute of Chemistry Chinese Academy of Sciences Beo＇ing 100080 China Graduate school of Chinese Academy of sciences Beijing 100080 China

Experimental miscibility studies were performed on different compositions of iPP/sPP blends, where sPP has a low syndiotacticity （[rrrr] = 81%）. Combining optical microscopy, rheology, and solid state NMR spectroscopy, the miscibility of the blends was investigated at different scales in the traditionally thought to be ＂immiscible＂ iPP/sPP blends. For the composition of iPP/sPP （90/10） blend, it shows to be miscible in the melt, and furthermore, the existence of intermolecular chain interactions between sPP and iPP components was detected in the solid state.

关键词： iPP/sPP blends Miscibility Optical microscopy Rheology Solid state NMR spectroscopy.

Conservation laws for energy and momentum in curved spaces

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Journal of Zhejiang University-science A(Applied Physics & Engineering) 2007年第4期8卷 665-668页

作者： LóPEZ-BONILLA J. MORALES J. OVANDO G. Section of postgraduate studies and Research Superior School of Mechanical and Electrical EngineeringNational Polytechnic InstituteCP 07738Mexico Division of Basic sciences and Engineering Autonomous Metropolitan UniversityCP 02200Mexico

In arbitrary Riemannian 4-spaces, continuity equations are constructed which could be interpreted as conservation laws for the energy and momentum of the gravitational field. Special attention is given to general relativity to obtain, of natural manner, the pseudotensors of Einstein, Landau-Lifshitz, Moeller, Goldberg and Stachel, and also the conservation equations of Komar, Trautman, DuPlessis and Moss.

关键词： Noether theorem Lagrangians in curved spaces Energy and momentum in Riemannian spaces Rund-Lovelock identities

Synthesis and Characterization of a Novel pH-sensitive Complex for Drug Release

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Journal of Wuhan University of Technology(Materials science) 2010年第1期25卷 24-27页

作者：许东颖李光吉 Department of polymer science and Engineering South China University of Technology

A novel pH-sensitive complex was prepared by using oxidized konjac glucomannan and 4-aminosalicylic acid （4-ASA） through glutaraldehyde as a cross-linking agent. The product was characterized by FTIR and 13C NMR spectra, and the thermogravimetric analysis was also studied. The drug release studies in vitro showed that the amount of 4-ASA released from the complex was about 4%, 56% and 17% after 12 h at pH 1.2, 6.8 and 7.4, respectively. The data demonstrate that the rate of the drug release of the complex can be more effectively controlled by pH value. The results showed that the novel pH-sensitive complex could be potentially useful for colon-targeting drug delivery system.

关键词： konjac glucomannan pH-sensitivity drug release