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Synthesis, Single-crystal Structure, and Optical and Magnetic Properties of CaEr_2S_4

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Chinese Journal of Structural Chemistry 2007年第8期26卷 973-979页

作者： ZENG Hui-Yi Mattausch Hansjtirgen zheng Fa-Kun DONG zhen-Chao GUO Guo-Cong HUANG Jin-shun State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter The Chinese Academy of Sciences Fuzhou Fujian 350002 China Max Planck Institute for Solid State Research Heisenbergstrasse 1 D-70569 Stuttgart Germany Hefei National Laboratory for Physical Sciences at Microscale University of Science and Technology of China Hefei Anhui 230026 China

Brown needle-like crystals of CaEr2S4 were isolated as the major product from a reaction of elements and binary sulfides by a two-step flux technique. CaEr2S4 crystallizes in the orthorhombic space group Pnma with a=12.845（4）, b=3.862（4）, c=13.001（2）（A）, V=645.0（7）（A）3,Z=4, F（000）=880,μ（MoKα）=27.794 mm^-1, the final R=0.0528 and wR=0.0562 for 1070observed reflections with I 〉 3σ（I）. The CaEr2S4 structure forms a three-dimensional framework that consists of interconnected tetra-octahedral Er4S18 fragments. Ca^2＋cations, in a monocapped trigonal prism geometry, are stuffed in two parallel rows into the one-dimensional channels along the b direction. CaEr2S4 is an infrared-transparent semiconductor with a band gap of 1.81 eV. Magnetic susceptibility measurements over 6～300 K indicate a Curie-Weiss paramagnetic behavior for the phase, with an effective magnetic moment of 9.64（1） μB per Er^3＋ ion.

关键词： rare-earth chalcogenides flux crystal growth crystal structure optical and magnetic properties

Dynamics of a Stochastic Epidemic Model with Age-group

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应用数学 2025年第1期38卷 294-307页

作者： LAN Xiaomin CHEN Guangmin ZHOU Ruiyang zheng Kuicheng CAI Shaojian WEI Fengying JIN zhen MAO Xuerong School of Mathematics and Statistics Fuzhou UniversityFuzhou 350116China Fujian Provincial Center for Disease Control and Prevention Fuzhou 350012China Center for Applied Mathematics of Fujian Province Fuzhou UniversityFuzhou 350116China Key Laboratory of Operations Research and Control of Universities in Fujian Fuzhou UniversityFuzhou 350116China Complex models Research Center Shanxi UniversityTaiyuan 030006China Department of Mathematics and Statistics University of StrathclydeGlasgowG11XHUK

A stochastic epidemic model with two age groups is established in this study,in which the susceptible(S),the exposed(E),the infected(I),the hospitalized(H)and the recovered(R)are involved within the total population,the aging rates between two age groups are set to be *** existence-and-uniqueness of global positive solution is firstly ***,by constructing several appropriate Lyapunov functions and using the high-dimensional Itô’s formula,the sufficient conditions for the stochastic extinction and stochastic persistence of the exposed individuals and the infected individuals are *** stochastic extinction indicator and the stochastic persistence indicator are less-valued expressions compared with the basic reproduction ***,the main results of this study are modified into multi-age ***,by using the surveillance data for Fujian Provincial Center for Disease Control and Prevention,Fuzhou COVID-19 epidemic is chosen to carry out the numerical simulations,which show that the age group of the population plays the vital role when studying infectious diseases.

关键词： Epidemic model Age groups Persistence Extinction

Yrast Bands Calculation for Odd-Odd Nuclei ^(160)Ho, ^(162)Tm and ^(164)Tm

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Chinese Physics Letters 1996年第7期13卷 504-507页

作者： ZHU shun-quan zheng Ren-rong Department of Physics Southwest Normal UniversityChongqing 630715

In this paper,the axial symmetry rotor plus quasiparticle model is generalized from odd nuclei to odd-odd *** spectra of yrast bands for nuclei ^(160)Ho,^(162)Tm and ^(164)Tm are calculated by using the *** inversions in these three nuclei are reproduced,and one possible signature inversion mechanism connected with the calculation is also discussed.

关键词： method symmetry

Polynomial-Time Key-Recovery Attacks Against NTRURe Encrypt from ASIACCS'15

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Journal of Systems Science & Complexity 2024年第3期37卷 1308-1325页

作者： LIU zhen PAN Yanbin zheng Jinwei School of Cyber Science and Technology Hubei Key Laboratory of Applied MathematicsHubei UniversityWuhan 430062China Key Laboratory of Mathematics Mechanization Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100190China

In ASIACCS 2015, Nu nez, et al. proposed a proxy re-encryption scheme, named NTRURe Encrypt, based on NTRU, which allows a proxy to translate ciphertext under the delegator’s public key into a re-encrypted ciphertext that can be decrypted correctly by delegatee’s private key. Because of the potential resistance to quantum algorithm, high efficiency and various applications in real life,NTRURe Encrypt has drawn lots of attention and its security has been widely discussed and *** PQCrypto2019, Liu, et al. proposed two key recovery attacks against it. However, their first attack heavily relies on a weaken decryption oracle, and the second attack needs to collect about 260ciphertexts from the same message by theoretical analysis, which makes both of the attacks unrealistic. In this paper, inspired by the broadcast attack against NTRU, the authors find out that for NTRURe Encrypt the delegator and the delegatee can efficiently recover each other’s private key in polynomial time without any unrealistic assumptions. In addition, the authors also show how to fix NTRURe Encrypt to resist the proposed attacks. As a by-product, the authors also show how to commit broadcast attacks against NTRU 2001 with even dg, which was thought infeasible before.

关键词： Broadcast attack key recovery NTRU NTRUReEncrypt

Anisotropic magnetocaloric effect in a dysprosium(Ⅲ) single-molecule magnet——Commemorating the 100th anniversary of the birth of Academician Guangxian Xu

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Journal of Rare Earths 2021年第12期39卷 1554-1559,I0004页

作者： You-Song Ding Yan-zhen zheng Xi'an Jiaotong University Shenzhen Research Academy Shenzhen 518057China Frontier Institute of Science and Technology Xi'an Jiaotong University

Dysprosium compounds with high magnetic anisotropy are widely studied as single molecule magnets(SMMs).Here the anisotropic magnetocaloric effect in a Dy(Ⅲ)SMM,{[Dy(OSiMe_(3))_(2)(4-Mepy)5(BPh_(4))]0.5 Toluene},was studied by single *** dependent magnetization can be observed at 300 K because of its high magnetic *** behavior measured along the easy axis direction is identical to that of the polycrystalline *** magnetization from the easy axis to the hard plane gives a maximum magnetic entropy change(-ΔSR)of 3.05 J/(kg·K)at 19 K atΔB=5 T,which enables the Dy(Ⅲ)SMM to be used as a low-temperature rotating magnetic refrigerant.

关键词： Lanthanide complex Magnetic anisotropy Rotate magnetocaloric effect Single molecule magnets Rare earths

Tourism Route Recommendation Based on A Multi-Objective Evolutionary Algorithm Using Two-Stage Decomposition and Pareto Layering

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IEEE/CAA Journal of Automatica Sinica 2023年第2期10卷 486-500页

作者： Xiaoyao zheng Baoting Han zhen Ni IEEE the School of Computer and Information Anhui Normal UniversityWuhu 241002China the Department of Electrical Engineering and Computer Science Florida Atlantic UniversityBoca Raton FL33431 USA

Tourism route planning is widely applied in the smart tourism *** Pareto-optimal front obtained by the traditional multi-objective evolutionary algorithm exhibits long tails,sharp peaks and disconnected regions problems,which leads to uneven distribution and weak diversity of optimization solutions of tourism *** by these limitations,we propose a multi-objective evolutionary algorithm for tourism route recommendation(MOTRR)with two-stage and Pareto layering based on *** method decomposes the multiobjective problem into several subproblems,and improves the distribution of solutions through a two-stage *** crowding degree mechanism between extreme and intermediate populations is used in the two-stage *** neighborhood is determined according to the weight of the subproblem for crossover ***,Pareto layering is used to improve the updating efficiency and population diversity of the *** two-stage method is combined with the Pareto layering structure,which not only maintains the distribution and diversity of the algorithm,but also avoids the same *** with several classical benchmark algorithms,the experimental results demonstrate competitive advantages on five test functions,hypervolume(HV)and inverted generational distance(IGD)*** the experimental results of real scenic spot datasets from two famous tourism social networking sites with vast amounts of users and large-scale online comments in Beijing,our proposed algorithm shows better *** proves that the tourism routes recommended by our proposed algorithm have better distribution and diversity,so that the recommended routes can better meet the personalized needs of tourists.

关键词： Evolutionary algorithm multi-objective optimization Pareto optimization tourism route recommendation two-stage decomposition

Extended Group Foliation Method and Functional Separation of Variables to Nonlinear Wave Equations

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Communications in Theoretical Physics 2005年第4X期44卷 577-582页

作者： QU Chang-zheng ZHANG shun-Li Center for Nonlinear Studies Northwest University Xi'an 710069 China Department of Mathematics Northwest University Xi'an 710069 China

Generalized functional separation of variables to nonlinear evolution equations is studied in terms of the extended group foliation method, which is based on the Lie point symmetry method. The approach is applied to nonlinear wave equations with variable speed and external force. A complete classification for the wave equation which admits functional separable solutions is presented. Some known results can be recovered by this approach.

关键词： symmetry group group foliation method nonlinear wave equation functional separation of variables

Enhancement of the mechanical properties of polylactic acid/basalt fiber composites via in-situ assembling silica nanospheres on the interface

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Journal of Materials Science & Technology 2021年第25期84卷 182-190页

作者： Xianliang Hou shun Yao zhen Wang Changqing Fang Tiehu Li School of Materials Science and Engineering Northwestern Polytechnical UniversityXi'an710072China Faculty of Printing Packaging and Digital Media TechnologyXi’an University of TechnologyXi'an710048China

A valid strategy to tailor the properties of polylactic acid for more extensive applications was introducing *** this work,basalt fiber assembled with in-situ SiO_(2) nanoparticles on the surface was successfully prepared via hydrothermal method and it was further treated with coupling agent KH-550 to improve interfacial interaction between polylactic acid(PLA)and basalt fibers(BF).It was demonstrated that the introduction of BFS could increase the crystallization of PLA and resulted in forming trans-crystallization based on TG and DSC *** tensile strength of PLA/BF composites raised from 39 MPa to 62.5 MPa with increasing the fiber loading from 1 wt%to 10 wt%.Furthermore,the interfacial interaction could be effectively improved by assembling SiO_(2)(especially with 250 nm in diameter)on BF surface to build mechanical locking,which could keep the PLA matrix in place during the mechanical deformation with the tensile strength value raised from 62.5 MPa to 74.0 *** is noticeable that the impact and flexural properties were effectively increased with the incorporation of in-situ SiO_(2) *** further KH-550 treatment made a positive impact as *** instance,the impact strength and flexural strength of the sample with SiO_(2) and KH-550 modification were improved to 22.49 k J/m^(2) and 146.83 MPa and it enhanced about 42.16%and 41.04%than those of neat PLA,***,an efficient enhancement of mechanical performance was achieved and this concept of assembling in-situ SiO_(2) on silica-based fiber as a modifier was a novel and simple path to design the interfacial construction and properties of the polymer composites.

关键词： Poly(lactic acid) Basalt fiber Silica nanoparticles In-situ assembled Interface interaction

A THEORETICAL MODEL FOR THERMAL-SENSITIVE MICROGEL WITH PNIPAM CORE AND ELASTIC SHELL

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Acta Mechanica Solida Sinica 2012年第5期25卷 520-529页

作者： zhen Wu zheng Zhong School of Aerospace Engineering and Applied Mechanics Tongji Universityshanghai 200092China

Poly （N-isopropylacrylamide）（PNIPAM） microgels are widely used in drug delivery due to their fast response to temperature. In order to get a better biocompatibility, PNIPAM mi- crogels are typically coated with a layer of biocompatible material, resulting in composite microgels with core-shell structure. In a composite microgel prepared recently, for example, a microsphere of PNIPAM gel is enclosed by a phospholipid membrane, and the composite microgel exhibits a substantial volume transition in response to temperature changes. Here we develop a theoretical model to describe the thermal-responsive behavior of this composite microgel. In particular, we treat the phospholipid membrane as an elastic layer behaving like rubber-like elastomers and adopt the form of the free-energy function for nematic gels （which refer to anther species of thermal- sensitive gels whose behavior has been intensively studied） as that for PNIPAM gels. We show that the thermal-responsive behavior of the composite microgel can be markedly influenced by the membrane. By investigating the state of stress on the interface, we further predict that when the coating membrane is stiff and thin, wrinkles are expected to occur on the outer surface of the composite microgel after the volume transition.

关键词： gel poly (N-isopropylacrylamide) volume transition core-shell structure