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Chinese Journal of Polymer Science 2014年第12期32卷 1724-1736页

作者： Yu-han Li Mi Zhou cheng-zhen geng 陈枫傅强 College of Polymer Science and Engineering State Key Laboratory of Polymer Materials Engineering Sichuan University

Inspired by the photoprotection, radical scavenging of melanin together with versatile adhesive ability of mussel proteins, polydopamine（PDA） nanoparticles were successfully prepared and incorporated into environmentally friendly polymer, poly（propylene carbonate）（PPC） via solvent blending. The prepared composites exhibited excellent thermal stability in air and nitrogen atmosphere and extraordinary mechanical properties. The composites displayed eminent increase of temperature at 5% weight loss（T5%） by 30-100 K with 0.3 wt%-2.0 wt% loadings, meanwhile, the tensile strength and Young＇s modulus were significantly improved from 11.5 MPa and 553.7 MPa to 40.5 MPa and 2411.2 MPa, respectively. The kinetic calculation indicated that improvement of T5% is presumably derived from suppressing chain-end unzipping. The glass transition temperature（Tg） of the PPC/PDA composites increased by 8-10 K. This is probably due to hydrogen bonding interaction since the abundant proton donors along PDA chains would interact with proton acceptors like C = O and C―O―C in PPC which would cause restriction of segmental motion of PPC chains.

关键词： Biodegradable polymers Reinforcements Mechanical properties Thermal properties Free radical scavenging

Mechanically Reinforced Chitosan/Cellulose Nanocrystals Composites with Good Transparency and Biocompatibility

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Chinese Journal of Polymer Science 2015年第1期33卷 61-69页

作者： cheng-zhen geng Xin Hu Guang-hui Yang Qin Zhang Feng Chen 傅强 College of Polymer Science and Engineering State Key Laboratory of Polymer Materials EngineeringSichuan University

Chitosan/cellulose nanocrystals（CS/CNCs） composites were prepared with different contents of CNCs. Due to the homogeneous dispersion of CNCs and the strong interfacial interactions resulting from hydrogen bonding between CS chains and CNCs, the transparency of CS is well retained and the overall mechanical properties of CS are significantly improved. Furthermore, because both CS and CNCs are biocompatible materials, cell proliferation test shows that the obtained composites are noncytotoxic and can potentially meet safety requirements of biomedical applications. These advantages pave the way of potential applications of CS in the field of commercial plastics and encourage the use of CS as environmentfriendly material and biomedical material.

关键词： Chitosan Cellulose nanocrystals Reinforcement Cytotoxicity.

Size Distribution and Anisotropy of the Minor Phase Droplets in Polypropylene/Ethylene-Octene Copolymer Blends: Effects of Shear and Component Miscibility

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Chinese Journal of Polymer Science 2014年第1期32卷 9-20页

作者： cheng-zhen geng Yan-ling Zhu Guang-hui Yang 傅强 Chao-liang Zhang Ke Wang Tian-nan Zhou College of Polymer Science and Engineering State Key Laboratory of Polymer Materials Engineering Sichuan University State Key Laboratory of Oral Diseases West China Hospital of Stomatology Sichuan University

In this work, polypropylene （PP）/octene-ethylene copolymer （POE） blends were injection-molded using the so- called dynamic packing injection technique, which imposed oscillatory shear on the gradually cooling melt during the packing solidification stage. In this way, the effect of shear on the size distribution and anisotropy of the minor phase droplets could be investigated. Besides, by using two kinds of POE with different octene contents, the effect of component miscibility was also studied. The results show that the droplet size is mainly determined by composition and miscibility, and droplet anisotropy is mainly determined by droplet size and shear. Most importantly, under the same processing condition, droplet anisotropy increases with droplet size, and there seems a linear fit between them, disregarding the miscibility factor. These results may provide guidance for preparing polymer blends with desired properties by tailoring their phase morphologies.

关键词： Shear Miscibility Size distribution Anisotropy Phase morphology.

Locally and globally uniform approximations for ruin probabilities of a nonstandard bidimensional risk model with subexponential claims

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Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 98-113页

作者： LIU Zai-ming geng Bing-zhen WANG Shi-jie School of Mathematics and Statistics Central South UniversityChangsha 410083China School of Big Data and Statistics Anhui UniversityHefei 230601China

Consider a nonstandard continuous-time bidimensional risk model with constant force of interest,in which the two classes of claims with subexponential distributions satisfy a general dependence structure and each pair of the claim-inter-arrival times is arbitrarily *** some mild conditions,we achieve a locally uniform approximation of the finite-time ruin probability for all time horizon within a finite *** we further assume that each pair of the claim-inter-arrival times is negative quadrant dependent and the two classes of claims are consistently-varying-tailed,it shows that the above obtained approximation is also globally uniform for all time horizon within an infinite interval.

关键词： bidimensional risk model asymptotic formula subexponential distribution consistently varying tail ruin probability

Unified Classification and Rejection:A One-versus-all Framework

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Machine Intelligence Research 2024年第5期21卷 870-887页

作者： zhen cheng Xu-Yao Zhang cheng-Lin Liu State Key Laboratory of Multimodal Artificial Intelligence Systems Institute of AutomationChinese Academy of SciencesBeijing100190China School of Artificial Intelligence University of Chinese Academy of SciencesBeijing100049China

Classifying patterns of known classes and rejecting ambiguous and novel(also called as out-of-distribution(OOD))inputs are involved in open world pattern *** neural network models usually excel in closed-set classification while perform poorly in rejecting OOD *** tackle this problem,numerous methods have been designed to perform open set recognition(OSR)or OOD rejection/detection *** methods mostly take post-training score transformation or hybrid models to ensure low scores on OOD inputs while separating known *** this paper,we attempt to build a unified framework for building open set classifiers for both classification and OOD *** formulate the open set recognition of K-known-class as a(K+1)-class classification problem with model trained on known-class samples *** decomposing the K-class problem into K one-versus-all(OVA)binary classification tasks and binding some parameters,we show that combining the scores of OVA classifiers can give(K+1)-class posterior probabilities,which enables classification and OOD rejection in a unified *** maintain the closed-set classification accuracy of the OVA trained classifier,we propose a hybrid training strategy combining OVA loss and multi-class cross-entropy *** implement the OVA framework and hybrid training strategy on the recently proposed convolutional prototype network and prototype classifier on vision transformer(ViT)*** on popular OSR and OOD detection datasets demonstrate that the proposed framework,using a single multi-class classifier,yields competitive performance in closed-set classification,OOD detection,and misclassification *** code is available at https://***/zhen-cheng121/CPN_OVA_unified.

关键词： Open set recognition out-of-distribution detection misclassification detection convolutional prototype network oneversus-all Dempster-Shafer theory of evidence

Stress relaxation properties of calcium silicate hydrate:a molecular dynamics study

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第2期25卷 97-115页

作者： Zhicheng geng Shengwen TANG Yang WANG Hubao A zhen HE Kai WU Lei WANG State Key Laboratory of Water Resources Engineering and Management Wuhan UniversityWuhan430072China Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education School of Materials Science and EngineeringTongji UniversityShanghai200092China College of Materials Science and Engineering Xi’an University of Architecture and TechnologyXi’an710055China

The time-dependent viscoelastic response of cement-based materials to applied deformation is far from fully understood at the atomic *** silicate hydrate(C-S-H),the main hydration product of Portland cement,is responsible for the viscoelastic mechanism of cement-based *** this study,a molecular model of C-S-H was developed to explain the stress relaxation characteristics of C-S-H at different initial deformation states,Ca/Si ratios,temperatures,and water contents,which cannot be accessed *** stress relaxation of C-S-H occurs regardless of whether it is subjected to initial shear,tensile,or compressive deformation,and shows a heterogeneous *** plays a crucial role in the stress relaxation process.A large Ca/Si ratio and high temperature reduce the cohesion between the calcium-silicate layer and the interlayer region,and the viscosity of the interlayer region,thereby accelerating the stress relaxation of *** effect of the hydrogen bond network and the morphology of C-S-H on the evolution of the stress relaxation characteristics of C-S-H at different water contents was elucidated by nonaffine mean squared *** results shed light on the stress relaxation characteristics of C-S-H from a microscopic perspective,bridging the gap between the microscopic phenomena and the underlying atomic-level mechanisms.

关键词： Calcium silicate hydrate(C-S-H) Stress relaxation Ca/Si ratio Temperature Water content Atomic simulation

Differential Operator Approach to■quantum Groups and Their Oscillator Representations

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Acta Mathematica Sinica,English Series 2024年第5期40卷 1360-1374页

作者： Zhao Bing FAN Ji cheng geng Shao Long HAN College of Mathematical Science Harbin Engineering UniversityHarbin 150001P.R.China

For a quasi-split Satake diagram,we define a modified q-Weyl algebra,and show that there is an algebra homomorphism between it and the corresponding■quantum *** other words,we provide a differential operator approach to■quantum ***,the oscillator representations of■quantum groups are *** crystal basis of the irreducible subrepresentations of these oscillator representations are constructed.

关键词： ■quantum group differential operator oscillator representation crystal basis

Recent advances and future prospects on Ni_(3)S_(2)-Based electrocatalysts for efficient alkaline water electrolysis

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Green Energy & Environment 2024年第4期9卷 659-683页

作者： Shiwen Wang zhen geng Songhu Bi Yuwei Wang Zijian Gao Liming Jin Cunman Zhang Clean Energy Automotive Engineering Center School of Automotive StudiesTongji UniversityShanghai201804China

Green hydrogen(H_(2))produced by renewable energy powered alkaline water electrolysis is a promising alternative to fossil fuels due to its high energy density with zero-carbon ***,efficient and economic H_(2) production by alkaline water electrolysis is hindered by the sluggish hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).Therefore,it is imperative to design and fabricate high-active and low-cost non-precious metal catalysts to improve the HER and OER performance,which affects the energy efficiency of alkaline water ***_(3)S_(2) with the heazlewoodite structure is a potential electrocatalyst with near-metal conductivity due to the Ni–Ni metal ***,the review comprehensively presents the recent progress of Ni_(3)S_(2)-based electrocatalysts for alkaline water ***,the HER and OER mechanisms,performance evaluation criteria,preparation methods,and strategies for performance improvement of Ni_(3)S_(2)-based electrocatalysts are *** challenges and perspectives are also analyzed.

关键词： Alkaline water electrolysis Hydrogen Electrocatalysts Ni_(3)S_(2)

Review on recent advances of inorganic electrode materials for potassium-ion batteries

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Tungsten 2024年第1期6卷 174-195页

作者： Jian-zhen Xiong Ze-cheng Yang Xin-Liang Guo Xi-Ying Wang Chao geng Zong-Fu Sun An-Yong Xiao Quan-Chao Zhuang Ya-Xin Chen Zhi-cheng Ju School of Materials Science and Physics China University of Mining and TechnologyXuzhou 221116China

Rechargeable potassium-ion batteries(PIBs)have great potential in the application of electrochemical energy storage devices due to the low cost,the abundant resources and the low standard reduction potential of *** electrode materials are the key factors to determine the electrochemical performance of devices,relevant research is being carried out to build high-performance *** recent years,significant progress has been made in the study of the design of inorganic electrode ***,we review the cathode materials(Prussian blue and its analogues,layered oxides and poly anionic compounds)and the anode materials(antimony-based,selenium-based and bismuth-based compounds).On the basis of previous work,the structural design principles for improving the performance of electrode materials are reasonably *** the same time,the problems that need to be solved in the preparation of electrode materials and the direction of future research and improvement are pointed out.

关键词： Inorganic electrode materials Potassium-ion batteries Cathode materials Anode materials

Novel process for facile preparation of mesoporous silica-based materials with controllable pore structure from coal fly ash Author links open overlay panel

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Particuology 2024年第8期91卷 128-137页

作者： Jian-ming Gao zhen Li Shujia Ma Yuanyuan Zhang Fangqin cheng Institute of Resources and Environment Engineering State Environmental Protection Key Laboratory of Efficient Utilization Technology of Coal Waste ResourcesShanxi Collaborative Innovation Center of High Value-added Utilization of Coal-related WastesShanxi UniversityTaiyuan 030006China

Extraction of silica from fly ash to produce mesoporous silica materials is one of the most important utilization *** silica could not be synthesized on a large-scale by conventional sol-gel *** this paper,facile preparation of mesoporous silica with controllable pore structure from fly ash by the template-free process via two steps of mineral phase transformation and selective acid etching was *** influence of crystalline structure and acid etching degree on structure of as-synthesized mesoporous silica materials was revealed,as well as mechanism of crystalline structure transformation and pore structure *** results show that mullite and quartz could be transformed into acid-soluble kaliophilite when fly ash reacted with K_(2)CO_(3)at temperature of 800-1100℃.The hexagonal kaliophilite would be transformed into orthorhombic KAlSiO_(4)-O1 phase when the temperature is controlled at 1100℃.Mesoporous silica with specific surface area of 475.93 m^(2)/g and 642.57 m^(2)/g could be synthesized from activated fly ash with kaliophilite and KAlSiO_(4)-O1 phase crystalline *** controlling the degree of acid etching,mesoporous silica materials with different pore structures can be *** paper provides a cost-effective and large-scale process for the preparation of mesoporous silica materials with controllable pore structure from solid waste fly ash.

关键词： Fly ash Mesoporous silica Crystal transformation Acid etching Controllable pore structure