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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.

Regional Stability of Positive Switched Linear Systems with Multi-equilibrium Points

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International Journal of Automation and computing 2017年第2期14卷 213-220页

作者： Zhi Liu yu-zhen Wang School of Control Science and Engineering Shandong University Ji'nan 250061 China

This paper studies the regional stability for positive switched linear systems with multi-equilibrium points （PSLS-MEP）. First, a sufficient condition is presented for the regional stability of PSLS-MEP via a common linear Lyapunov function. Second, by establishing multiple Lyapunov functions, a dwell time based condition is proposed for the regional stability analysis. Third, a suprasphere which contains all equilibrium points is constructed as a stability region of the considered PSLS-MEP, which is less conservative than existing results. Finally, the study of an illustrative example shows that the obtained results are effective in the regional stability analysis of PSLS-MEP.

关键词： Regional stability positive switched linear system multi-equilibrium points common linear Lyapunov function multipleLyapunov function.

MODELLING STRAIN-RATE-DEPENDENCY OF NATURAL SOFT CLAYS COMBINED WITH ANISOTROPY AND DESTRUCTURATION

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Acta Mechanica Solida Sinica 2011年第3期24卷 216-230页

作者： zhen-yu Yin Minna Karstunen Department of Civil Engineering Shanghai Jiao Tong University Shanghai 200240 China Department of Civil Engineering University of Strathclyde John Anderson Building 107 Rottenrow Glasgow G40NG UK

The paper aims to investigate modelling the strain-rate-dependency of natural soft clays combined with anisotropy and destructuration using an elasto-viscoplastic model. The model is based on Perzyna＇s overstress theory and the elastoplastic model S-CLAYIS. Tests at constant strain^rate and creep tests under both one-dimensional and triaxial conditions on several clays are simulated. Simulations highlight the loading scenarios in which it is necessary to account for anisotropy and/or destructuration in order to get accurate predictions. Comparisons between the predicted and measured results demonstrate that the proposed model can successfully reproduce the time-dependent behaviour of natural soft clays under different loading conditions.

关键词： anisotropic materials creep debonding time-dependent

Anisotropic phononic crystal structure with low-frequency bandgap and heat flux manipulation

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Science China(Physics,Mechanics & Astronomy) 2020年第2期63卷 93-103页

作者： Ting Guo XiongWei Yang Qian geng zhen Li yueMing Li Xian Wang Hu Zhang State Key Laboratory for Strength and Vibration of Mechanical Structures Shaanxi Key Laboratory of Environment and Control for Flight Vehicle School of Aerospace Xi’an Jiaotong University

This study presents a two-dimensional phononic crystal with heat flux manipulation and wide bandgaps of out-of-plane modes within the low-frequency range. The anisotropic matrix made of spiral-multilayered materials with different thermal conductivities, and the coating layer inserted with metal are designed for heat flux manipulation. Rubber-coated metal cylinders are periodically embedded in the anisotropic matrix to obtain the low-frequency bandgaps of out-of-plane modes. Numerical simulation is carried out to validate the heat and elastic characteristics of the spiral-multilayered anisotropic structure and reveal the effects of the laying angle and temperature on the bandgaps. Subsequently, a spiral-multilayered plate with periodic structures is studied, which shows an obvious vibration attenuation in the frequency ranges of the bandgaps and a deflected heat flux from the initial propagation direction. In the experimental investigation, the multi-phase spiral-multilayered anisotropic plate is simplified to a single-phase anisotropic plate made of aluminum. The characteristics of this type of anisotropic phononic crystal structure may pave the way for the design of a new kind of thermo-acoustic metamaterial serving in combined thermal and acoustic environments.

关键词： heat flux manipulation bandgap anisotropic structure thermal stress spiral-multilayered structure

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)

GAAF:Searching Activation Functions for Binary Neural Networks Through Genetic Algorithm

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Tsinghua Science and Technology 2023年第1期28卷 207-220页

作者： Yanfei Li Tong geng Samuel Stein Ang Li Huimin yu Department of Information Science and Electronic Engineering Zhejiang UniversityHangzhou 310027China h Pacific Northwest National Laboratory RichlandWA 99354USA

Binary neural networks(BNNs)show promising utilization in cost and power-restricted domains such as edge devices and mobile *** is due to its significantly less computation and storage demand,but at the cost of degraded *** close the accuracy gap,in this paper we propose to add a complementary activation function(AF)ahead of the sign based binarization,and rely on the genetic algorithm(GA)to automatically search for the ideal *** AFs can help extract extra information from the input data in the forward pass,while allowing improved gradient approximation in the backward *** novel AFs are identified through our GA-based search,while most of them show improved performance(up to 2.54%on ImageNet)when testing on different datasets and network ***,periodic functions are identified as a key component for most of the discovered AFs,which rarely exist in human designed *** method offers a novel approach for designing general and application-specific BNN *** will be released on GitHub.

关键词： binary neural networks(BNNs) genetic algorithm activation function

Important role of the ENSO combination mode in the maintenance of the anomalous anticyclone over the western North Pacific in boreal summer

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Science China Earth Sciences 2022年第7期65卷 1379-1387页

作者： Wenjun ZHANG Zuoli yu Feng JIANG Xin geng Renhe ZHANG CIC-FEMD/ILCEC Key Laboratory of Meteorological Disaster of Ministry of Education(KLME)/School of Atmospheric SciencesNanjing University of Information Science and TechnologyNanjing 210044China Zhangjiagang Meteorological Bureau Suzhou 215600China Institute of Atmospheric and Oceanic Sciences Fudan UniversityShanghai 200433China

This study demonstrates the main physical mechanism for the maintenance of the western North Pacific(WNP)anomalous anticyclone(WNPAC)during the El Niño decaying summer by analyzing the respective effects of the cold sea surface temperature(SST)anomalies in the WNP,the warm SST anomalies in the Indian Ocean(IO),and the El Niño and Southern Oscillation(ENSO)combination *** find that the WNPAC is usually accompanied by significant cold WNP SST anomalies in the El Niño mature winter and following spring,which almost disappear in the decaying summer and cannot explain the maintenance of the WNPAC in *** influence of the IO warm SST anomalies on the WNPAC exhibits conspicuous decadal *** the 2000 s,the IO warm SST anomalies played a role in the WNPAC maintenance through the response of the baroclinic atmospheric Kelvin wave;however,this effect cannot be evidently detected after the 2000 *** decadal difference may be related to changes in the decaying speed of ENSO *** contrast to El Niño events before the 2000 s,El Niño events after the 2000 s decay more rapidly,and the associated tropical central-eastern Pacific SST features a La Ni?a-like condition in the El Niño decaying ***,no significant warm SST anomalies appear over the tropical Indian Ocean,exerting a weak influence on the *** to the cold WNP SSTanomalies and warm IO SST anomalies,the ENSO combination mode,originating from the nonlinear interaction between ENSO and the annual cycle,has a relatively stable relationship with the WNPAC during the El Niño decaying summer,which exhibits a crucial role in the maintenance of the *** the persistence of the ENSO combination mode,the WNPAC and associated climate variability during the El Niño decaying summer can be skillfully predicted at least one season in advance based on the ENSO combination mode.

关键词： ENSO WNP anomalous anticyclone ENSO combination mode

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Highly Stereoselective Synthesis of 2,2-Disubstituted Vinylphosphonates via Aryl to Vinyl 1,4-Palladium Migration

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Chinese Journal of Chemistry 2022年第18期40卷 2188-2192页

作者： Yan-zhen Chen geng-yu Bao Xin-Chen Zhan Jian-Guo Fu Xiao-Ming Ji Shu-Sheng Zhang Chen-Guo Feng The Research Center of Chiral Drugs Innovation Research Institute of Traditional Chinese MedicineShanghai University of Traditional Chinese MedicineShanghai201203 China

Vinylphosphates play an important role in the fields of synthetic chemistry,pharmaceuticals and material *** is a long-standing challenge to control the geometry of multi-substituted ***,an efficient method for the synthesis of 2,2-disubstituted vinylphosphonates has been *** reaction proceeded via aryl to vinyl 1,4-palladium migration progress,in which two difficulties that the deactivation of palladium catalyst by the coordination of excess secondary phosphine oxide and the competitive cross-coupling to form arylphosphonates are successfully *** judicious selection of phosphine ligand is the key to *** protocol features excellent regio-and stereoselectivitiy,generally excellent reaction yields and broad substrate socpe.

关键词： 1,4-Palladium migration Phosphorylation C-H activation Stereoselectivity Cross-coupling

Split nitrogen fertilizer application improved grain yield in winter wheat (Triticum aestivum L.) via modulating antioxidant capacity and ^(13)C photosynthate mobilization under water-saving irrigation conditions

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Ecological Processes 2021年第1期10卷 290-302页

作者： zhen Zhang zhenwen yu Yongli Zhang yu Shi Key Laboratory of Crop Ecophysiology and Farming System Ministry of AgricultureShandong Agricultural UniversityTai-an 271017ShandongChina

A water-saving cultivation technique of supplementary irrigation based on soil moisture levels has been adopted for winter wheat production in the Huang-Huai-Hai Plain of China,due to the enhanced water-use ***,appropriate split nitrogen management may further improve crop growth and grain ***,we conducted a 2-year field experiment to determine if split nitrogen management might improve wheat productivity by enhancing ^(13)C photosynthate mobilization and the antioxidant defense system under water-saving *** nitrogen management involved a constant total nitrogen rate(240 kg ha^(−1))split in four different proportions between sowing and jointing stage,i.e.,10:0(N1),7:3(N2),5:5(N3),and 3:7(N4).The N3 treatment significantly enhanced“soil-plant analysis development”values,superoxide dismutase antioxidant activity,soluble protein content,sucrose content,and sucrose phosphate synthetase activity,although it reduced the accumulation of malondialdehyde(MDA).The N3 treatment ultimately increased the amount of dry matter assimilation after anthesis *** addition,the ^(13)C isotope tracer experiment revealed that the N3 treatment promoted the assimilation of carbohydrates after anthesis and their partitioning to the developing *** to the unequal ratio treatments(N1,N2,and N4),the equal ratio treatment(N3)increased grain yield by 5.70–16.72%via increasing 1000-grain weight and number of grains per spike in both growing ***,we recommend the use of a 5:5 basal-topdressing split nitrogen fertilizer application under water-saving irrigation conditions to promote antioxidant enzyme activity and the remobilization of photosynthate after anthesis for improving wheat grain yield.

关键词： Split nitrogen fertilization Modulating antioxidant capacity ^(13)C photosynthate mobilization Water-saving irrigation