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Fabrication of metal-organic framework-based nanofibrous separator via one-pot electrospinning strategy

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Nano Research 2021年第5期14卷 1465-1470页

作者： Congcong Chen weidong zhang He Zhu Bo-Geng Li Yingying Lu Shiping Zhu State Key Lab of Chemical Engineering College of Chemical and Biological EngineeringZhejiang UniversityHangzhou310027China Institute of Pharmaceutical Engineering College of Chemical and Biological EngineeringZhejiang UniversityHangzhou310027China School of Science and Engineering The Chinese University of Hong KongShenzhenShenzhen518172China Department of Chemical Engineering McMaster UniversityHamiltonOntarioL8S 4L7Canada

Metal-organic framework(MOF)/polymer composites have attracted extensive attention in the recent ***,it still remains challenging to efficiently and effectively fabricate these composite *** this study,we propose a facile one-pot electrospinning strategy for preparation of HKUST-1/polyacrylonitrile(PAN)nanofibrous membranes from a homogeneous stock solution containing HKUST-1 precursors and *** crystallization and polymer solidification occur simultaneously during the electrospinning process,thus avoiding the issues of aggregation and troublesome multistep fabrication of the conventional *** obtained HKUST-1/PAN electrospun membranes show uniform MOF distribution throughout the nanofibers and yield good mechanical *** membranes are used as separators in Li-metal full batteries under harsh testing conditions,using an ultrathin Li-metal anode,a high mass loading cathode,and the HKUST-1/PAN nanofibrous *** results demonstrate significantly improved cycling performance(capacity retention of 83.1%after 200 cycles)under a low negative to positive capacity ratio(N/P ratio of 1.86).The improvement can be attributed to an enhanced wettability of the separator towards electrolyte stemmed from the nanofibrous structure,and a uniform lithium ion flux stabilized by the open metal sites of uniformly distributed HKUST-1 particles in the membrane during cycling.

关键词： one-pot electrospinning strategy metal-organic framework composite nanofibrous membrane battery separator

A Novel System Model based on Cost-prediction for Spectrum Leasing in Cognitive Radio

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China Communications 2010年第2期7卷 32-41页

作者： Wang weidong Wang Ben zhang Yinghai Zhao Xinlei Wang Shoufeng Information ＆ Electronics Technology Lab Beijing University of Posts and Telecommunications Beijing 100876 China

In current researches on spectrum leasing, Common model and Property-right model are two main approaches to dynamic spectrum sharing. However, Common model does not consider the obligation of Primary System (PS) and is unfair to Secondary System (SS), while the cooperation based on Property-rights model has problems on its feasibility. This paper proposes a novel system model, in which a Cost-Prediction scheme for Spectrum Leasing (CPSL scheme) is designed to forecast the cost that PS would pay for leasing spectrum. Cost Function is introduced as a criterion to evaluate the potential cost of spectrum leasing for PS. The simulation results show that compared with Common model based scheme, CPSL scheme substantially improves the QoS of the delay-sensitive traffic in SS at the cost of a small degradation of PS performance.

关键词： cognitive radio spectrum leasing cost prediction dynamic spectrum sharing CPSL

An experimental study of shear strength of gas-hydrate-bearing core samples

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Petroleum Science 2011年第2期8卷 177-182页

作者： zhang weidong Ma Qingtao Wang Ruihe Ren Shaoran School of Petroleum Engineering China University of Petroleum Dongying Shandong 257061 China

The shear strength of gas-hydrate-bearing reservoirs is one of the most important parameters used to study mechanical properties of gas-hydrate-bearing reservoirs. The shear strength of gas-hydrate- bearing reservoirs changes with filling and cementation of gas hydrates, which will affect the wellbore and reservoir stability. Traditional shear tests could not be conducted on gas-hydrate-bearing core samples because the gas hydrates exist under a limited range of temperature and pressure conditions. This paper describes a novel shear apparatus for studying shear strength of gas-hydrate-bearing core samples under original reservoir conditions. The preparation of gas-hydrate-bearing core samples and subsequent shear tests are done in the same cell. Cohesion and internal friction angle of the core samples with different saturations of gas hydrates were measured with the apparatus. The effect of gas hydrates on the shear strength of reservoirs was quantitatively analyzed. This provides a foundation for studying wellbore and reservoir stability of gas-hydrate-bearing reservoirs.

关键词： Natural gas hydrate reservoir experimental apparatus shear test internal cohesion internalfriction angle

A novel microwave absorption and dielectric spectrum detection technology in photoelectron dynamic study for solar cells

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Rare Metals 2006年第Z1期25卷 153-157页

作者： LI Xiaowei SUN Shuxu LAI weidong zhang Rongxiang DAI Xiuhong JIANG Xiaoli College of Physics Science & Technology Hebei University Baoding 071002 China College of Physics Science & Technology Hebei University Baoding 071002 China College of Physics Science & Technology Hebei University Baoding 071002 China College of Physics Science & Technology Hebei University Baoding 071002 China College of Physics Science & Technology Hebei University Baoding 071002 China College of Physics Science & Technology Hebei University Baoding 071002 China

The photoelectron property is directly related to the light-energy conversion efficiency of solar cells. In this paper, the photoelectron dynamic of semiconductor was analyzed. The diffusion of electrons has influence on the dielectric function of the solar cell material. And the amplitude variance of the imaginary and real part of the dielectric function is in direct proportion to the dynamic process of free and shallow-trapped electrons. Based on the untouched detection technique, the method is present to detect the amplitude change of the microwave signal which is passing through the material whose dielectric function changes after exposure. A 35 GHz oscillator was used as a microwave source. The absorption and dispersion microwave signals, which contain the dynamic information of free and shallow-trapped electron signal, are split respectively with phase-sensitive instrument. The photoelectron character of n-type Si(100) thin film was investigated by the novel equipment, and the lifetime of different kinds of electrons with the resolution of 1 ns was obtained. The equipment can be directly used in the study of the optoelectronic conversion mechanism of solar cells.

关键词： dye sensitization solar cells microwave absorption dielectric spectrum

Strengthening in Al-,Mo-or Ti-doped CoCrFeNi high entropy alloys:A parallel comparison

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Journal of Materials Science & Technology 2021年第35期94卷 264-274页

作者： Xi Li Zhongtao Li Zhenggang Wu Shijun Zhao weidong zhang Hongbin Bei Yanfei Gao College of Materials Science and Engineering&Hunan Province Key Laboratory for Spray Deposition Technology and Application Hunan UniversityChangsha 410082China Department of Mechanical Engineering City University of Hong KongHong KongChina epartment of Materials Science and Engineering Center of Electron Microscopy and State Key Laboratory of Silicon MaterialsZhejiang UniversityHangzhou 310027China Department of Materials Science and Engineering University of TennesseeKnoxvilleTN 37996United States

In the current work,a parallel comparison of the influence of Al,Mo and Ti,on the microstructure and strengthening of the CoCrFeNi alloy was *** achieve this,inconsistencies on variables including the extent of alloying,thermomechanical processing and property-evaluation method were ***,following cold-rolling,annealing of the 4 at.%Al-doped alloys at 800-1000℃ did not result in phase separation;nevertheless,that of the 4 at.%Mo-and Ti-doped alloys led to the respective formation ofσandηphase and,consequently,caused extra strengthening through the Orowan dislocation bypassing *** systematic qualitative analysis and DFT calculations showed that Al and Ti are more effective than Mo in reducing the stacking fault energy(SFE)of the CoCrFeNi alloy,because they can induce more considerable deformation of electronic density,making the gliding of atomic layers *** identical thermomechnical processing,Al-,Mo-,and Ti-doping causes different extent of solid solution strengthening and grain boundary *** causes the most pronounced solid solution strengthening but does not benefit the grain boundary strengthening;in contrast,the effectiveness of grain boundary strengthening is boosted by the doping Al and *** analyses support that Labusch instead of Fleischer mechanism is applicable to explain the differences in solid solution strengthening,and the observed differences in grain boundary strengthening arise from the different tendency of Al,Mo and Ti to reduce the SFE of *** addition,we determined the value of the dimensionless parameter f in the Labusch model for CoCrFeNi-based alloys and observed a close relation between Hall-Petch slope and *** more in-depth studies are needed to provide full and mechanistic understandings,both these findings in fact presents significant values toward designing novel singlephase high-strength CoCrFeNi-based alloys through manipulating the solid solution an

关键词： CoCrFeNi alloy Compositional effect Solid solution strengthening Grain boundary strengthening Precipitation strengthening Stacking fault energy

Corrosion Behavior of Pre-oxidized GH4169 Alloy with Solid NaCI Deposited in a Wet Oxygen Flow at 600 ℃

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Acta Metallurgica Sinica(English Letters) 2024年第7期37卷 1249-1264页

作者： weidong zhang Yu Cui Li Liu Wenquan Wang Wenzheng Chen Rui Li Fuhui Wang Shenyang National Laboratory for Materials Science Northeastern UniversityShenyang110819China Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang110016China

The corrosion behavior of the pre-oxidized GH4169 alloy was studied after 20 h of exposure under a solid NaCl deposit film in a wet O_(2) environment at 600℃ by mass-gain measurements,X-ray diffraction,scanning electron microscopy,transmission electron microscopy *** results indicate that the pre-oxidized GH4169 alloy undergoes serious corrosion in the corrosive *** preformed Cr_(2)O_(3) layer is gradually destroyed by deposit NaCl,and the inner Nb2O5 layer beneath the complete outer Cr_(2)O_(3) layer also reacts with NaCl to form NaNbO_(3).The electrochemical test results testified the existence of electrochemical reactions during this corrosion *** corrosion behavior of pre-oxidized GH4169 under a solid NaCl deposit film in a wet O_(2) environment at 600℃has been discussed in detail.

关键词： Pre-oxidation Solid NaCl Wet O2 Electrochemical corrosion

Analytical design of PI controller for AQM with robustness adjustability

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Frontiers of Electrical and Electronic Engineering in China 2008年第2期3卷 240-245页

作者： Danying GU Jiwen YANG weidong zhang Shanghai Jiao Tong University Shanghai 200240China

Based on a linearized TCP/AQM model,a new proportional integral(PI)controller design approach is *** analytical approach applies H_(∞) optimization and internal model control(IMC)theory to design active queue management(AQM)routers that support transmission control protocol(TCP)*** most important feature of the proposed scheme lies in that it can be explicitly tuned with a single parameter for the trade-off between performance and stability of the AQM control *** is thus flexible and easy to use in *** proposed method and the designed PI controller are verified and compared with other existing AQM schemes using ns-2 *** results show the advantages of the new PI controller design approach for AQM routers supporting TCP flows.

关键词： active queue management(AQM) proportional integral(PI)controller transmission control pro-tocol(TCP) time delay robustness

Does nitrogen fertilization impact nonstructural carbohydrate storage in evergreen Podocarpus macrophyllus saplings?

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Journal of Forestry Research 2021年第4期32卷 1653-1661页

作者： Renshan Li Jianming Han Liqiong Zhu Lijun Zhao Xiangling Huang Mingyue zhang Qingpeng Yang weidong zhang Life Science Department Luoyang Normal UniversityLuoyang 471934People’s Republic of China College of Forestry Guangxi UniversityNanning 530004People’s Republic of China Key Laboratory of Forest Ecology and Management Institute of Applied EcologyChinese Academy of SciencesShenyang 110016People’s Republic of China Huitong National Research Station of Forest Ecosystem Huitong 418307People’s Republic of China

Nonstructural carbon(NSC),which represents the relationship between the carbon source and carbon sink,is an important factor that reflects the functions and performance of a ***,little is known regarding the timeseries responses of NSC storage in evergreen species to different nitrogen(N)fertilization *** study,which was based on a pot experiment,examined the response of the NSC(soluble sugars and starch storage to different N addition intensities[light N addition(LN):6.5 g N m^(-2)a^(-1);moderate N addition(MN):13.0 g N m^(-2)a^(-1);and heavy N addition(HN):26.0 g N m^(-2)a^(-1))]in saplings of the evergreen species Podocarpus *** results showed that the net photosynthetic rate(P_(n))under MN was significantly higher than that under LN,but was comparable to that under ***,saplings subject to MN had a significant higher leaf biomass than that to LN and *** results indicated that the C supply via photosynthesis under MN was greater than that under LN and *** NSCs reserve under MN was considerable with that under LN,which suggested that saplings in MN group consumed higher and stored lower properties of NSCs than those in LN ***,saplings under HN stored higher properties of NSCs than those under MN considering that no difference in NSCs pools was found between the two *** leaf N concentrations were found in the increasing sequence of LN

关键词： Photosynthate Allocation Source-sink balance Plant nutrient supply Podocarpus macrophyllus saplings

Speed Control for Sensorless SPMSM via Variable Structure Controller and EMF-Based Position Estimation Scheme 36

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Speed Control for Sensorless SPMSM via Variable Structure Co...