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Science China Chemistry 2023年第9期66卷 2563-2568页

作者： Xiao-Lu Wang Linfeng Liang Shuai Dou xian-ming Zhang Institute of Crystalline Materials Shanxi UniversityTaiyuan 030006China Institute of Urban Environment Chinese Academy of SciencesXiamen 361021China College of Chemistry Taiyuan University of TechnologyTaiyuan 030024China

By tactically integrating two different kinds of proton donors and acceptors into one supramolecular tecton, a new crystalline hydrogen-bonded organic framework(HOF-SXU-1) has been developed. HOF-SXU-1 features a remarkable proton conductivity as high as 6.32 mS cm^(-1) and an extremely low activation energy of 0.16 eV at 160℃ under anhydrous N_(2) *** contrast, under identical conditions, the organic precursors of HOF-SXU-1 only exhibit negligible proton conduction performance, demonstrating that the formation of HOF is crucial for excellent proton conduction performance.

关键词： two-in-one strategy hydrogen-bonded organic framework proton conduction solid state electrolyte

Trapping, Transporting, and Splitting Cold Molecules Employing a Spatial Liquid Crystal Modulator

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Chinese Physics Letters 2013年第1期30卷 63-66页

作者： GONG Tian-Lin huang Yun-Xia MU Ren-Wang JI xian-ming YANG Xiao-Hua School of Science Nantong UniversityNantong 226019 State Key Laboratory of Precision Spectroscopy East China Normal UniversityShanghai 200062

Optically transporting and splitting cold molecules are proposed by spatially pure phase modulating a Gaussian laser beam with a spatial liquid crystal modulator(SLM).Taking the experimentally available cold KRb molecules(350 nK)as an example,the computations show that the trapping depth is about 460μK and the trap can be split and transported up to 1 cm when a commercially available SLM is employed.

关键词： modulator Crystal Optically

Dynamic Theory of Die Swell for Entangled Polymeric Liquids in Tube Extrusion： Correlations of Total and Ultimate Extrudate Swell Effects to Growth Time, Shear Stress and Aspect Ratio Under the Free States

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Chinese Journal of Chemical Physics 2008年第1期21卷 55-68页

作者： Jing Zhao ming-shi Song Chang-wei Zhu Gui-xian Hu Ke-jian Wang Da-ming Wu School of Mechanical and Electrical Engineering Belting University of Chemical and TechnologyBeijing 100029 China School of Materials Science and Engineering Beifing University of Chemical and TechnologyBeijing 100029 China

The dynamic theory of die swell deduced in a previous paper was extensively applied to study the extrudate swelling behaviors of two entangled polymeric liquids （HDPE and PBD） in a simple shear flow at steady shear stress. The mechanism and dynamics for the recoils and the recoveries of viscoelastic strains in the extrudate were investigated under the free recovery and dynamic states. It was found that in the course of recovery the free recoil and the growth of die swell in the extrudate may be divided into two recovery regions （instantaneous and delayed regions） and three growth stages （instantaneous, delayed, and ultimate extrudate swelling stages）. The free recoil and the extrudate swelling behaviors may be expressed as a function of shear stress. The correlations of instantaneous, delayed, total and ultimate extrudate swell effects to the molecular parameters and the operational variables in the simple shear flow at steady shear stress were derived from the dynamic theory of die swell. Also, two sets of new universal equations on the total extrudate swelling effect （TESE） and ultimate extrudate swelling effect （UESE） were deduced. The first is the universal equation of the logarithmic correlation between the TESE and the growth time under the free and dynamic states; the second is the universal equation of the logarithmic correlation between the UESE and the operational variables under the free and equilibrium states. The first equation was verified by experimental data of PBD with different molecular weights at different operational variables. The second equation was verified by experimental data of HDPE at two temperatures and different operational variables. An excellent agreement result was obtained. The excellent agreement shows that the two universal equations can be used directly to predict the correlations of the TESE and UESE to the growth time, the molecular parameters, and the operational variables under the dynamic and equilibrium states.

关键词： Die swell Entanglement Viscoelastic recoil

Crystalline-amorphous M@MN_x(M=Co,Fe,Ni)encapsulated in nitrogen-doped carbon for enhanced efficient and durable hydrogen evolution reaction

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Rare Metals 2024年第4期43卷 1547-1556页

作者： Yang Yang Xiao-Chuan Duan Shao-Hui Guo xian-ming Zhang College of Materials Science and Engineering College of ChemistryKey Laboratory of Interface Science and Engineering in Advanced MaterialsTaiyuan University of TechnologyYuci030600China

Developing earth-abundant electrocatalysts for hydrogen evolution reaction(HER)is important for the sustainable energy ***,efficient and stable heterocatalysts consisting of crystalline-amorphous M@MN_(x)(M=Co,Fe,Ni)encapsulated in N-doped carbon layers supported with N-doped graphene sheets(denoted as M@MN_(x)@NC-NG)are synthesized by facile hydrothermal reaction and nitridation *** the nitriding process,metal ions in M(tzbc)_2(H_(2)O)_4(tzbc=4-(1H-1,2,4-triazol-1-yl)benzoic acid)complexes are reduced to crystalline M cores,accompanied by the formation of amorphous MN_(x)shells;the tzbc ligands are insitu carbonized to form outermost N-doped carbon(NC)layers that connect with inner MN_(x)via M-N-C motifs inherited from the complex precursors and inhibit the transition of MN_(x)from amorphous to crystalline *** Co@CoN_(x)@NC-NG catalyst exhibits excellent HER activity with small overpotentials of 45 and 64 mV at a cathode current density of 10 mA·cm^(-2)and low Tafel slopes of 40 and 85 mV·dec^(-1)in 0.5 mol·L^(-1)H_(2)SO_4 and1.0 mol·L^(-1)KOH electrolytes,*** Co@CoN_(x)@NC-NG retains 97%of the initial overpotential after 100,000 s in both acidic and alkaline *** outstanding HER performance originates from the crystalline-amorphous Co@CoN_(x)that redistributes electrons around the heterointerfaces,facilitating the conversion process of H^(+)/H_(2)O to hydrogen and thereby promoting HER *** outermost NC layers serve as the armor of Co@CoN_(x),and graphene nanosheets act as carriers of egg-like Co@CoN_(x)@NC and conduction paths for electron shuttles,ensuring stable and continuous electrocatalytic hydrogen production.

关键词： Hydrogen evolution reaction Electrocatalysts Iron group metals Heterojunction Crystalline-amorphous structure

Numerical analysis of heat transfer enhancement on steam condensation in the presence of air outside the tube

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Nuclear Science and Techniques 2022年第8期33卷 55-68页

作者： Wen-Tao Li xian-Ke Meng Hao-Zhi Bian ming Ding Heilongjiang Provincial Key Laboratory of Nuclear Power System and Equipment Harbin Engineering UniversityHarbin 150001China China Nuclear Engineering Consulting Co. Ltd.Beijing 100073China

In loss-of-coolant accidents,a passive containment heat removal system protects the integrity of the containment by condensing *** a large amount of air exists in the containment,the steam condensation heat transfer can be significantly *** on previous research,traditional methods for enhancing pure steam condensation may not be applicable to steam–air *** the present study,new methods of enhancing condensation heat transfer were adopted and several potentially enhanced heat transfer tubes,including corrugated tubes,spiral fin tubes,and ring fin tubes were ***-CCM+was used to determine the effect of enhanced heat transfer tubes on the steam condensation heat *** to the calculations,the gas pressure ranged from 0.2 to 1.6 MPa,and air mass fraction ranged from 0.1 to *** effective perturbation of the high-concentration air layer was identified as the key factor for enhancing steam–air condensation heat ***,the designed corrugated tube performed well at atmospheric pressure,with a maximum enhancement of 27.4%,and performed poorly at high *** the design of spiral fin tubes,special attention should be paid to the locations that may accumulate high-concentration ***,the ring-fin tubes generally displayed good performance under all conditions of interest,with a maximum enhancement of 24.2%.

关键词： Air–steam condensation Numerical simulation Heat transfer enhancement Fin tube

Characteristic analysis of a Smith–Purcell terahertz source

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Photonics Research 2016年第5期4卷 162-167页

作者： xian-Zhu Meng ming-Hong Wang Li-ming Zhang Zhong-Min Ren Shandong Provincial Key Laboratory of Optical Communication Science and Technology School of Physics Science and Information Engineering Liaocheng University

We investigate a novel Smith–Purcell terahertz source. This device is composed of an electron gun, a cylindrical resonator, a metallic grating, and a collector. The characteristics of the Smith–Purcell terahertz source are discussed with the help of three-dimensional particle-in-cell simulation. In this device, coherent and high-power Smith–Purcell radiation(SPR) at the terahertz frequency range can be produced for the reasonable parameters of charge energy and grating. Our results indicate that coherent SPR at 506.529 GHz with a power around 1000 W can be obtained for a grating of period l=0.3 mm operating at the beam energy E=50 keV and beam current I=10 A.

关键词： cell THz Purcell terahertz source Characteristic analysis of a Smith

Time-variant reliability analysis of a continuous system with strength deterioration based on subset simulation

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Advances in Manufacturing 2019年第2期7卷 188-198页

作者： Xi-Nong En Yi-Min Zhang xian-Zhen huang School of Mechanical Engineering and Automation Northeastern University Shenyang 110819 People's Republic of China Equipment Reliability Institute Shenyang University of Chemical Technology Shenyang 110142 People's Republic of China

To conduct a reliability analysis for mechanical components, it is necessary to consider the combined influence of strength deterioration and dynamic loads. An efficient method based on subset simulation is proposed in this paper to analyze time-variant reliability by considering the strength deterioration of mechanical components in a continuous system. A gamma process is used to describe the deterioration of system strength. A model for timevariant reliability considering strength deterioration is constructed for a continuous system. A representative example and tubular cantilever structure are assessed to demonstrate the efficiency and accuracy of the proposed method. The reliability probability examples were analyzed using a first-order reliability method and benchmark results for the proposed method were derived using direct Monte Carlo simulation (MCS). The results of the proposed method and MCS are consistent, indicating that the proposed method is an effective reliability analysis method for evaluating small failure probabilities in a continuous system subjected to strength deterioration and dynamic loads.

关键词： Time-variant reliability Strength deterioration Subset simulation (SS) Continuous system

MANAGING REDISTRIBUTION OF TOLL REVENUE WITH USER HETEROGENEITY

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Journal of Systems Science and Systems Engineering 2014年第3期23卷 330-342页

作者： Shu-xian Xu Tian-Liang Liu Hai-Jun huang School of Economics and Management Beihang University

With the explicit consideration of user heterogeneity, i.e., each user has a different value of time （VOT）, this paper examines the system efficiency and social equity of toll revenue redistribution in a bi-mode transportation system. Three schemes of distributing the road toll revenue are proposed, which respectively consider efficiency, equity, as well as efficiency and equity together. With mild assumptions, we prove that the number of auto-motorists decreases and the total social cost increases with transit subsidy share when only marginal operating cost of the transit is covered by its fare. However, when average fixed cost of the transit is further covered, the total social cost is a ＂U＂ shape curve against the transit subsidy share. Numerical results show that the well designed toll revenue redistribution schemes can make the system more equitable while keeping high efficiency. With the increase of user heterogeneity, the Gini coefficient becomes larger while the total social cost goes down.

关键词： Mode choice value of time toll revenue redistribution efficiency equity

Geometric Phase in a Time-Dependent A-Type Jaynes-Cummings Model

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Communications in Theoretical Physics 2009年第3期51卷 407-410页

作者： QIN xian-ming YU Zbao-xian JIAO Zhi-Yong XIE Bing-Hao Department of Mathematics and Physics Chongqing University of Science and Technology Chongqing 400042 China Department of Physics Beijing Information Science and Technology University Beijing 100192 China Department of Physics China University of Petroleum （East China） Dongying 257061 China

By using the Lewis-Riesenfeld invariant theory, we have studied the dynamical and the geometric phases in a generalized time-dependent A-type Jaynes Cummings model. We lind that, compared with the dynamical phases, the geometric phases in a cycle case are independent of the frequency of the photon field, the coupling coefficient between photons and atoms, and the atom transition frequency. It is pointed out that the geometric phases in a cycle ease can be measured under the case of a stronger time-dependent photon field and a stronger coupling photon-atom system. On the other hand, the geometric phases of the model may be measured in the composition of cold atoms.

关键词： geometric phase generalized Jaynes-Cummings model

Microstructure and hot flow stress at 970℃ of various heat-treated Ti2AlNb sheets

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Rare Metals 2020年第6期39卷 695-706页

作者： Yong Wu Rong-Lei Fan xian-Jun Zhou ming-He Chen College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

The microstructure and hot tensile behaviors of the different heat-treated Ti2AlNb sheets were investigated by backscattered electron image(BSE),electron backscattering diffraction(EBSD),transmission electron microscope(TEM)and tensile *** grain sizes and contents ofα2,B2/βand O phases were quantitatively *** the heating time increases at 970℃,the mean grain size and content ofα2-phase *** grain shapes and distributions of the O-phase lamellar grains were affected by the heat *** plastic deformation promoted the O→B2/βphase transition and the globularization of O-phase lamellar grains at 970℃.Calculated by the creep equation and the iso-stress method,the grain size exponent wasμ=1.1 and the relationship between the material constants of B2/βand O phase was KO=1.14KB2/β.

关键词： Ti2AlNb alloy Heat treatment Tensile behaviors Microstructure evolution