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journal of Magnesium and Alloys 2021年第3期9卷 1007-1018页

作者： L.B.Tong j.h.Chu W.T.Sun Z.h.jiang D.N.Zou S.F.Liu S.Kamado M.Y.zheng School of Metallurgical Engineering Xi'an University of Architecture and TechnologyXi'an 710055China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China School of Materials Science and Engineering Jilin UniversityChangchun 130025China Department of Mechanical Engineering Nagaoka University of TechnologyNagaoka 940-2188Japan

In the current study,a homogenous ultra-fine grained microstructure with average grain size of 1.0μm is achieved in the Mg-Zn-Ca-Mn alloy through the reduplicative equal channel angular pressing(ECAP)at 300℃,and the mechanical properties are remarkably improved,with room-temperature yield strength of 269.6 MPa and elongation of 22.7%.The twinning deformation results in a discontinuous recrystallization behavior in the initial stage of *** further deformation,the continuously dynamic recrystallization contributes to an obvious grain refinement *** activation of non-basal slip system leads to the formation of a unique basal texture,which is related to the elevated ECAP temperature and the decreased grain *** grain refinement and texture modification derived from ECAP process result in the increase of yield strength,while the cracked secondary phase particles are beneficial to the enhanced ductility,through reducing the stress concentration and hindering premature failure.

关键词： Mg alloy ECAP Microstructural evolution high strength Superior ductility

Nodal superconducting gap in LiFeP revealed by NMR:Contrast with LiFeAs

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Chinese Physics B 2021年第4期30卷 113-118页

作者： A F Fang R Zhou h Tukada j Yang Z Deng X C Wang C Q jin Guo-Qing zheng Department of Physics Beijing Normal UniversityBeijing 100875China Institute of Physics Chinese Academy of Sciencesand Beijing National Laboratory for Condensed Matter PhysicsBeijing 100190China Songshan Lake Materials Laboratory Dongguan 523808China Department of Physics Okayama UniversityOkayama 700-8530Japan

Identifying the uniqueness of FeP-based superconductors may shed new lights on the mechanism of superconductivity in ***,we report nuclear magnetic resonance(NMR) studies on LiFeP and LiFeAs which have the same crystal structure but different pnictogen *** NMR spectrum is sensitive to inhomogeneous magnetic fields in the vortex state and can provide the information on the superconducting pairing symmetry through the temperature dependence of London penetration depth λ_(L).We find that λ_(L) saturates below T~0.2 T_(C) in LiFeAs,where T_(C) is the superconducting transition temperature,indicating nodeless superconducting ***,by using a two-gaps model,we simulate the temperature dependence of λ_(L) and obtain the superconducting gaps of LiFeAs,as Δ_(1)=1.2 kB T_(C) and Δ_(2)=2.8 k_(B)T_(C),in agreement with previous result from spin-lattice *** LiFeP,in contrast,λ_(L) does not show any saturation down to T~0.03 T_(C),indicating nodes in the superconducting gap ***,we demonstrate that strong spin fluctuations with diffusive characteristics exist in LiFeP,as in some cuprate high temperature superconductors.

关键词： iron-based superconductor nuclear magnetic resonance superconducting pairing symmetry spin fluctuations

Three-dimensional structure of the wild-type RhDV

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Chinese Science Bulletin 2001年第12期46卷 1005-1009页

作者： zheng Dong XUE Tao ChEN Donghua zheng Ming Z.h.ZhOU XU Wei Beijing Laboratory of Electron Microscopy Institute of PhysicsChinese Academy of SciencesBeijing 100080China Department of Pathology and Laboratory Medicine University of Texas-Houston Medical SchoolHoustonTX 77030USA Institute of Biophysics Chinese Academy of SciencesBeijing 100101China Analytical and Testing Center Beijing Normal UniversityBeijing 100875China China Institute of Veterinary Drug Control Beijing 100081China

The three-dimensional (3D) structure of the wild-type rabbit hemorrhagic disease virus (RhDV) has been determined to a resolution of 3.2 nm by electron cryo-microscopy and computer image reconstruction techniques. The 3D density map exhibits characteristic structural features of a calicivirus: a T=3 icosahedral capsid with 90 arch-like capsomeres at the icosahedral and local 2-fold axes and 32 large surface hollows at the icosahedral 5- and 3-fold axes. This result confirms that the RhDV isolated in China is a member of the Caliciviridae family. A rather continuous capsid shell was found without channels. however, our RhDV structure also reveals some distinct structural char-acteristics not observed in other caliciviruses, including interconnected capsomeres and the lack of protuberance on the base of each of the surface hollows. Two types of particles were identified with similar outer capsid structure but different density distributions inside the capsid shells, which could not be distinguished by

关键词： electron cryomicroscopy three-dimensional reconstruction RhDV calicivirus.

Observation of geometric phase in a dispersively coupled resonator-qutrit system

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Chinese Physics B 2018年第7期27卷 133-137页

作者： Libo Zhang Chao Song h Wang Shi-Biao zheng Department of Physics Zhejiang UniversityHangzhou 310027China Fujian Key Laboratory of Quantum Information and Quantum Optics College of Physics and Information EngineeringFuzhou University.Fuzhou 350116China

We present an experiment of observing the geometric phase in a superconducting circuit where the resonator and the qutrit energy levels are dispersively coupled. The drive applied to the resonator displaces its state components associated with the qutrit＇s ground state and first-excited state along different circular trajectories in phase space. We identify the resonator＇s phase-space trajectories by Wigner tomography using an ancilla qubit, following which we observe the difference between the geometric phases associated with these trajectories using Ramsey interferometry. This geometric phase is further used to construct the single-qubit It-phase gate with a process fidelity of 0.851± 0.001.

关键词： geometric phase superconducting circuit Wigner tomography

An Indirect Finite Element Method for Variable-Coefficient Space-Fractional Diffusion Equations and Its Optimal-Order Error Estimates

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Communications on Applied Mathematics and Computation 2020年第1期2卷 147-162页

作者： Xiangcheng zheng V.j.Ervin hong Wang Department of Mathematics University of South CarolinaColumbiaSC 29208USA Department of Mathematical Sciences Clemson UniversityClemsonSC 29634-0975USA

We study an indirect finite element approximation for two-sided space-fractional diffusion equations in one space *** the representation formula of the solutions u(x)to the proposed variable coefficient models in terms of v(x),the solutions to the constant coefficient analogues,we apply finite element methods for the constant coefficient fractional diffusion equations to solve for the approximations vh(x)to v(x)and then obtain the approximations uh(x)of u(x)by plugging vh(x)into the representation of u(x).Optimal-order convergence estimates of u(x)−uh(x)are proved in both L2 and hα∕2 *** numerical experiments are presented to demonstrate the sharpness of the derived error estimates.

关键词： Fractional diffusion equation Finite element method Convergence estimate

Formation of β' phase in LPSO structures in an Mg88Co5Y7 alloy

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journal of Magnesium and Alloys 2022年第1期10卷 175-182页

作者： Q.Q.jin X.h.Shao Y.T.Zhou B.Zhang S.j.zheng X.L.Ma Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences72 Wenhua Road110016 ShenyangChina Materials Science and Engineering Research Center Guangxi University of Science and TechnologyLiuzhou 545006China School of Materials Science and Engineering Research Institute for Energy Equipment MaterialsHebei University of TechnologyTianjin 300130China

Formation of β’ phase in long-period stacking ordered(LPSO) structures in an Mg;Co;Y;(at.%) alloy after aging at 200 °C for 24 h or electron beam(EB) irradiation has been studied by high-angle annular dark-field scanning transmission electron microscopy(hAADFSTEM). β’ phase was precipitated only in the Mg matrix but not in LPSO structures after aging at 200 °C for 24 h. LPSO structure containing stacking defects transforms into the β’-long phase during EB irradiation, which plays a key role in accelerating solute atoms’ diffusion. New complex β’(LPSO) structures formed in the alloy after EB irradiation, such as β’(12 h) structure with an orthorhombic lattice(Mg;Y, Cmcm,a = 2 _(a0)= 0.642 nm, b=4√3_(a0), c = 6 _(c0)= 3.12 nm).

关键词： Magnesium alloys Long-period stacking ordered(LPSO)structure hAADF-STEM β’phase

Thermal performance and reduction kinetic analysis of cold-bonded pellets with CO and h2 mixtures

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International journal of Minerals,Metallurgy and Materials 2018年第7期25卷 752-761页

作者： Rong-rong Wang jian-liang Zhang h-ran Liu An-yang zheng zheng-jian Liu Xing-le Liu Zhan-guo Li School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China School of Chemical Engineering University of New South WalesSydneyAustralia

Cold-bonded pellets, to which a new type of inorganic binder was applied, were reduced by h2~CO mixtures with different hjCO molar ratios （1：0, 5：2, 1：1, 2：5, and 0：1） under various temperatures （1023, 1123, 1223, 1323, and 1423 K） in a daermogravimetric analysis appaxatus. The effects of gas composition, temperature, and binder ratio on the reduction process were studied, and the microstxucture of re- duced pellets was observed by scanning electron microscopy-energy-dispersive spectrometry （SEM-EDS）. The SEM-EDS images show that binder particles exist in pellets in two forms, and the form that binder particles completely surround ore particles has a more significant hin- der effect on the reduction. The reduction equilibrium constant, effective diffusion coefficient, and the reaction rate constant were calculated on the basis of the unreacted core model, and the promotion effect of temperature on reduction was further analyzed. The results show that no sintering phenomenon occurred at low temperatures and that the increasing reaction rate constant and high gas diffusion coefficient could main- tain the promotion effect of temperature; however, when the sintering phenomenon occurs at high temperatures, gas diffusion is hindered and the promotion effect is diminished. The contribution of the overajl equilibrium constant to the promotion effect depends on the gas composition.

关键词： cold-bonded pellets inorganic binder reduction fraction reduction kinetic model sintering phenomenon

A new type of cell related to organ movement for selfing in plants

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National Science Review 2023年第9期10卷 190-203页

作者： Yin-zheng Wang Yan-Xiang Lin Qi Liu jing Liu Spencer C.h.Barrett State Key Laboratory of Systematic and Evolutionary Botany Institute of BotanyChinese Academy of Sciences China National Botanical Garden College of Life Sciences University of Chinese Academy of Sciences College of Pharmacy Fujian University of Traditional Chinese Medicine Department of Ecology and Evolutionary Biology University of Toronto

Many plants employ osmotic and hydrostatic pressure to generate movement for survival,but little is known about the cellular mechanisms ***,we report a new cell type in angiosperms termed ’contractile cells’ in the stigmas of the flowering plant Chirita pumila with a much-expanded rough endoplasmic reticulum(RER).Cryo-scanning electron microscopy and transmission electron microscopy analyses revealed that the RER is continuously distributed throughout the entirety of cells,confirmed by endoplasmic reticulum(ER)-specific fluorescent labeling,and is distinct from the common feature of plant *** RER is water-sensitive and extremely elongated with water *** show that the contractile cells drive circadian stigma closing-bending movements in response to day-to-night moisture ***-seq analyses demonstrated that contractile cells have distinct molecular ***,multiple microstructural changes in stigma movements convert an anti-selfing structure into a device promoting selfing—a unique cellular mechanism of reproductive adaptation for uncertain pollination environments.

关键词： stigma movement rough endoplasmic reticulum contractile cells circadian moisture changes reproductive transition

Estimations of primary production and export production in the South China Sea based on sediment trap experiments

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Chinese Science Bulletin 1998年第7期43卷 583-586页

作者： jianfang Chen Lianfu zheng M. G. Wiesner Ronghua Chen Yulong zheng h. K. Wong SOA Inst Oceanog 2 Hangzhou 310012 Peoples R China Univ hamburg Inst Biogeochem & Marine Chem D-20146 Hamburg Germany

The results of time series sediment trap experiments in the South China Sea show that particulate organic carbon (POC) fluxes are influenced by the monsoons. The increase of productivity in the northern South China Sea is mainly due to northeast monsoon while in the central South China Sea the influence of southwest monsoon becomes more prominent. The annual primary production and export production calculated based on POC fluxes are 53 0-63 4 and 10 32-12 93 gC·m -2·a -1, respectively. The enhancement of POC flux during monsoon period suggest that higher palaeoproductivity or organic carbon accumulation rate in glacial age in the South China Sea might be the result of strengthening of the monsoons.

关键词： South China Sea POC flux sediment trap primary production export production

Mid-infrared superabsorbers based on quasi-periodic moiré metasurfaces

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Chinese Optics Letters 2018年第5期16卷 12-16页

作者： Yaoran Liu Zilong Wu Eric h. hill Yuebing zheng Department of Mechanical Engineering and Texas Materials Institute The University of Texas at Austin Austin Texas 78712 USA

We report on mid-infrared superabsorbers based on quasi-periodic moiré metasurfaces in metal-insulator-metal form. By varying the spacer thickness, moiré rotation angle, and filling factor of the superabsorbers, we can tune narrowband or broadband absorption in a systematic way. With their high tunability of near-unity absorption and simple fabrication, in combination with decoupled mode theory for an efficient design, moiré superabsorbers are well-suited for a wide range of applications in sensing, imaging, and communication.

关键词： Mid-infrared superabsorbers based on quasi-periodic moir metasurfaces