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Chinese Physics B 2017年第2期26卷 452-460页

作者： q.m.hmood m Hassan m A Faridi Department of Physics University of the Punjab Quaid-e-Azam Campus-54590 Lahore Pakistan Centre for High Energy Physics University of the Punjab Lahore Pakistan

We present structural,magnetic and optical characteristics of Zn_（1-x）Tm_xTe（Tm = mn,Fe,Co,Ni and x = 6.25%）,calculated through Wien2 k code,by using full potential linearized augmented plane wave（FP-LAPW） *** optimization of the crystal structures have been done to compare the ferromagnetic（Fm） and antiferromagnetic（AFm） ground state energies,to elucidate the ferromagnetic phase stability,which further has been verified through the formation and cohesive ***,the estimated Curie temperatures T_c have demonstrated above room temperature ferromagnetism（RTFm） in Zn_（1-x）Tm_xTe（Tm =mn,Fe,Co,Ni and x= 6.25%）.The calculated electronic properties have depicted that mn- and Co-doped ZnTe behave as ferromagnetic semiconductors,while half-metallic ferromagnetic behaviors are observed in Fe- and Ni-doped *** presence of ferromagnetism is also demonstrated to be due to both the p-d and s-d hybridizations between the host lattice cations and Tm *** calculated band gaps and static real dielectric constants have been observed to vary according to Penn＇s *** evaluated band gaps lie in near visible and ultraviolet regions,which make these materials suitable for various important device applications in optoelectronic and spintronic.

关键词： magnetic semiconductors density functional theory optical and dielectric properties electron density of states and band structure of crystalline solids

Reliability of quasi integrable and non-resonant Hamiltonian systems under fractional Gaussian noise excitation

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Acta mechanica Sinica 2020年第4期36卷 902-909页

作者： q.F.Lu W.q.Zhu m.L.Deng Department of mechanics State-Key Laboratory of Fluid Power and Mechatronic SystemsZhejiang UniversityHangzhou 310027China

The reliability of quasi integrable and non-resonant Hamiltonian system under fractional Gaussian noise(fGn)excitation is *** rather flat fGn power spectral density(PSD)in most part of frequency band,the fGn is innovatively regarded as a wide-band ***,the stochastic averaging method for quasi integrable Hamiltonian systems under wide-band noise excitation is applied to reduce 2n-dimensional original system into n-dimensional averaged ltd stochastic differential equations(SDEs).Reliability function and mean first passage time are obtained by solving the associated backward Kolmogorov equation and Pontryagin *** validity of the proposed procedure is tested by applying it to an example and comparing the numerical results with those from monte Carlo simulation.

关键词： Reliability Fkst passage time quasi integrable and non-resonant Hamiltonian systems Fractional Gauss noise

Gnetifolin K, a New Stilbene Diglucoside from Gnetum parvifolium

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Chinese Chemical Letters 1997年第6期8卷 509-510页

作者： Xu, q Lin, m CHINESE ACAD mED SCI INST MAT MEDBEIJING 100050PEOPLES R CHINA BEIJING UNION mED COLL BEIJING 100050PEOPLES R CHINA

A new stilbene diglucoside, gnetifolin K, was isolated from the lianas of Gnetum parvifolium. Its structure was established as isorhapotigenin-3,4'-di-O-beta-D-glucoside on the basis of spectral and chemical evidence.

关键词： Gnetifolin K a New Stilbene Diglucoside from Gnetum parvifolium

Stochastic averaging of quasi integrable and resonant Hamiltonian systems excited by fractional Gaussian noise with Hurst index 1/2

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Acta mechanica Solida Sinica 2017年第1期30卷 11-19页

作者： q.F.Lü m.L.Deng W.q.Zhu Department of mechanics State Key Laboratory of Fluid Power and Mechatronic SystemsKey Laboratory of Soft Machines and Smart Devices of Zhejiang ProvinceZhejiang University

A stochastic averaging method of quasi integrable and resonant Hamiltonian systems under excitation of fractional Gaussian noise （fGn） with the Hurst index 1/2 〈 H 〈 1 is proposed. First, the definition and the basic property of fGn and related fractional Brownian motion （iBm） are briefly introduced. Then, the averaged fractional stochastic differential equations （SDEs） for the first integrals and combinations of angle variables of the associated Hamiltonian systems are derived. The stationary probability density and statistics of the original systems are then obtained approximately by simulating the averaged SDEs numerically. An example is worked out to illustrate the proposed stochastic averaging method. It is shown that the results obtained by using the proposed stochastic averaging method and those from digital simulation of original system agree well.

关键词： quasi integrable and resonant Hamiltonian system Fractional Brownian motion Fractional Gaussian noise Stochastic averaging method Internal resonant

Strain Growth in Containment Vessels

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Transactions of Tianjin University 2006年第B9期12卷 193-198页

作者： DONG q LI q m ZHENG J Y School of mechanical Aerospace and Civil Engineering The University of Manchester PO Box 88 Manchester M60 1QD UK Institute of Chemical machinery Zhejiang University Hangzhou 310027 China

Strain growth is a phenomenon observed in containment vessels subjected to internal blast loading. The elastic response of the vessel may become larger in a later stage compared to its response during the initial stage. The dynamic responses of infinitely long cylindrical containment vessels subjected to uniformly-distributed internal blast loading are studied using LS-DYNA. The development of bending modes and the interaction between the breathing mode and bending modes are observed. The methodology developed for dynamic elastic buckling analysis is employed to study the strain growth phenomenon in explosion containment vessels. It is shown that the dynamic instable vibration of a containment vessel is the basic mechanism of strain growth.

关键词： strain growth containment vessel dynamic response impulsive loading

Theoretical investigation of optical properties and band gap engineering for Zn1-xTmxTe(Tm=Fe,Co)alloys by modified Becke-Johnson potential

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Chinese Physics B 2017年第8期26卷 491-498页

作者： q.m.hmood m Yaseen m Hassan Shahid m Ramay Asif mahmood materials Growth and Simulation Laboratory Department of PhysicsUniversity of the PunjabQuaid-i-Azam Campus54590LahorePakistan Department Of Physlcs University of Agriculture UniversityFaisalabad 38040Pakistan Physics and Astronomy Department College of ScienceKing Sand UniversityRiyadhSaudi Arabia Chemical Engineering Department College of EngineeringKing Saud UniversityRiyadhSaudi Arabia

The direct band gap ZnTe with transition metal （Tm） impurities plays a vital role in optoelectronic and spintronic applications. In the present study, we use the advanced modified Becke-Johnson （mBJ） functional for performing the structural computations and detailed investigations of the optical characters in Zn1_xTmxTe （Tm = Fe, Co） alloys with 0 ≤ x ≤1. By employing the FP-LAPW method, we determine various optical parameters for the ternary alloys and for the end binaries. The calculated static dielectric constants and optical band gaps for Zn1_xTmxTe （Tm = Fe, Co） have an inverse relation that verifies the Penn model. We find that the static dielectric constant is nearly equal to the square of the static refractive index, and both increase with Tm content. Furthermore, we also find a slight shift of peaks to a higher energy region with increasing Tm concentration. The decreasing band gap and high value of the absorption in the visible region of electromagnetic spectrum make these alloys suitable for photonic and solar cell applications.

关键词： amorphous semiconductors transition metal-doped ZnTe structural computation optical property

COSET DIAGRAmS FOR A HOmOmORPHIC ImAGE OFΔ(3,3,k)

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Acta mathematica Scientia 2008年第2期28卷 363-370页

作者： m.Ashiq q.mushtaq Department of Basic Sciences and Humanities College of E and mE National University of Sciences and Technology RawalpindiPakistan Department of mathematics quaid-i-Azam University IslamabadPakistan

Let q be a prime power. By PL（Fq） the authors mean a projective line over the finite field Fq with the additional point ∞. In this article, the authors parametrize the conjugacy classes of nondegenerate homomorphisms which represent actions of △（3, 3, k） = （u, v： u^3 = v^3 = （uv）^k = 1〉on PL（Fq）, where q ≡ ±1（modk）. Also, for various values of k, they find the conditions for the existence of coset diagrams depicting the permutation actions of △（3, 3, k） on PL（Fq）. The conditions are polynomials with integer coefficients and the diagrams are such that every vertex in them is fixed by （u^-v^-）^k. In this way, they get △（3, 3, k） as permutation groups on PL（Fq）.

关键词： Coset diagrams conjugacy classes nondegenerate homomorphism projec tire line and triangle groups

Stability and optoelectronic property of low-dimensional organic tin bromide perovskites

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Chinese Physics B 2021年第3期30卷 483-487页

作者： J H Lei q Tang J He m q Cai School of Science Hunan University of TechnologyZhuzhou 412007China School of Physics and Electronics Science Hunan UniversityChangsha 410082China

The toxicity and degradation of hybrid lead-halide perovskites hinder their extensive *** is thus of great importance to explore non-toxic alternative materials with excellent stability and optoelectronic *** investigate the atomic structures and optoelectronic properties of non-toxic organic tin bromide perovskites(OTBP)with one/zerodimensional(1D/0D)structures by first-principles *** calculated atomic structures show that the 1D/0D OTBPs are stable and the structure of inorganic octahedra in 0D is higher order than that in ***,the origination of exceptional purity emitting light in experiments is explained based on the calculated electronic structure.

关键词： one/zero dimensional non-toxic organic tin bromide perovskites first principle calculation stability Optoelectronic property

A new model for the expansion tube considering the stress coupling:Theory,experiments and simulations

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Defence Technology（防务技术） 2022年第7期18卷 1190-1204页

作者： m.Z.Wu X.W.Zhang q.m.Zhang State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyHaidian DistrictBeijing10081China

Based on the two-arc profile assumption,the expansion deformation and energy absorption of circular tubes compressed by conical-cylindrical dies were ***,the deformation of the two arcs was analyzed independently and an improved model denoted as model-I was ***,by further involving the coupling between the bending moment and membrane forces,a more elaborate model,i.e.,model-II was ***,experiments and simulations were conducted to verify the models,which show that,compared with previous theoretical models,model-II could not only capture the prominent features of the deformation,but also improve the prediction accuracy of the steady driving force *** means of this model,it was found that the critical semi-conical angle,which makes the driving force minimum,increases with the increase of the friction coefficient,expansion ratio as well as the radius/thickness ratio of the ***,the energy dissipation due to stretching is always greater than that of bending,while the friction dissipation can account for the largest proportion at small semi-conical angle or large friction *** a certain friction and die conditions,the specific energy absorption of expanded tubes can be much higher than that under progressive collapse mode.

关键词： Expansion Circular tube Stress coupling Strain hardening Energy absorption

mechanical properties of cocoons constructed consecutively by a single silkworm caterpillar,Bombyx mori

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Acta mechanica Sinica 2008年第2期24卷 151-160页

作者： S.q.Huang H.P.Zhao X.q.Feng W.Cui Z.Lin m.q.Xu Department of Engineering mechanics FML Tsinghua University Beijing 100084 China Department of Sericulture Shandong Agriculture University Tai'an 271018 China Department of Landscape Architecture Human Environment-Biological Polytechnic College. Hengyang 421005 China

most animals have the ability to adapt, to some extends and in different ways, the variation or disturbance of environment. In our experiments, we forced a silkworm caterpillar to spin two, three or four thin cocoons by taking it out from the cocoon being constructed. The mechanical properties of these cocoons were studied by static tensile tests and dynamic mechanical thermal analysis. Though external disturbances may cause the decrease in the total weight of silk spun by the silkworm, a gradual enhancement was interestingly found in the mechanical properties of these thin cocoons. Scanning electron microscopy observations of the fractured specimens of the cocoons showed that there exist several different energy dissipation mechanisms occurred simultaneously at macro-, meso-, and micro-scales, yielding a superior capacity of cocoons to adsorb the energy of possible attacks from the outside and to protect efficiently its pupa against damage. Through evolution of millions of years, therefore, the silkworm Bombyx mori seems to have gained the ability to adapt external disturbances and to redesign a new cocoon with optimized protective function when its first cocoon has been damaged for some reasons.

关键词： Silk Silkworm cocoon mechanical property Biomimetics