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PARAREAL ALGORITHMS APPLIED TO STOCHASTIC DIFFERENTIAL EQUATIONS WITH CONSERVED QUANTITIES

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Journal of Computational Mathematics 2019年第1期37卷 48-60页

作者： liying zhang Weien Zhou Lihai Ji School of Mathematical Science China University of Mining and TechnologyBeijing 100083China National Innovation Institute of Defense Technology Beijing 100000China College of Science National University of Defense TechnologyChangsha 410072China Institute of Applied Physics and Computational Mathematics Beijing 100088China

In this paper,we couple the parareal algorithm with projection methods of the trajectory on a specifc manifold,defined by the preservation of some conserved quantities of stochastic differential ***,projection methods are introduced as the coarse and fine ***,we apply the projection methods for systems with conserved quantities in the correction step of original parareal ***,three mumerical experiments are performed by different kinds of algorithms to show the property of convergence in iteration,and preservation in conserved quantities of model systems.

关键词： Stochastic differential equation Parareal algorithm Conserved quantity Structurepreserving method

The electromagnetically induced transparency in the Y-type four-level atom system at low light levels

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Science China(Physics,Mechanics & Astronomy) 2005年第5期48卷 593-599页

作者： zhang liying LIU Zhengdong CHEN Jun Institute of Modern Physics Nanchang University Nanchang 330047 China Institute of Modern Physics Nanchang University Nanchang 330047 China Institute of Modern Physics Nanchang University Nanchang 330047 China

In this paper a Y-type four-level atom interacting with external fields system is investigated. It is shown that increasing the control field can reduce the probe absorption, the electromagnetically induced transparency (EIT) and gain can be obtained if the parameters are taken appropriately. An interesting phenomenon is found that the system appears to be probe gain in a large region if the external fields Rabi phases are taken appropriately, too.

关键词： quantum optics, the nonlinear effect at low light levels, EIT, spontaneous emission, quantum interference.

Nanomaterials for Cardiac Tissue Engineering Application

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Nano-Micro Letters 2011年第4期3卷 270-277页

作者： Yachen zhang Yong Tang Ying Wang liying zhang Division of Cardiology Xinhua Hospital School of MedicineShanghai Jiaotong University Key Laboratory for Thin Film and Microfabrication of Ministry of Education Research Institute of Micro/Nanometer Science and TechnologyShanghai Jiaotong University

In recent years, the emerging cardiac tissue engineering provides a new therapeutic method for heart diseases. And in the tissue engineering, the scaffold material which can mimic the structure of the extracellular matrix properly is a key factor. The rapid expansion of nano-scaffolds during the past ten years has led to new perspectives and advances in biomedical research as well as in clinical practice. Here we search articles published in recent years extensively on cardiac tissue engineering scaffold materials and nanotechnology. And we review the traditional scaffold materials and the advances of the nano-scaffolds in cardiac tissue engineering. A thorough understanding of the nano-scaffolds would enable us to better exploit technologies to research the ideal scaffold material, and promote the cardiac tissue engineering using in the clinical practice as soon as possible.

关键词： Cardiac tissue engineering Nano-scaffolds Nanomaterials

CONVERGENCE ANALYSIS OF PARAREAL ALGORITHM BASED ON MILSTEIN SCHEME FOR STOCHASTIC DIFFERENTIAL EQUATIONS

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Journal of Computational Mathematics 2020年第3期38卷 487-501页

作者： liying zhang Jing Wang Weien Zhou Landong Liu Li zhang School of Mathematical Science China University of Mining and TechnologyBeijing 100083China National Innovation Institute of Defense Technology Chinese Academy of Military ScienceBeijing 100101China Department of Foundation Courses Beijing Union UniversityBeijing 100101China

In this paper,we propose a parareal algorithm for stochastic differential equations(SDEs),which proceeds as a two-level temporal parallelizable integrator with the Milstein scheme as the coarse propagator and the exact solution as the fine *** convergence order of the proposed algorithm is analyzed under some regular ***,numerical experiments are dedicated to illustrate the convergence and the convergence order with respect to the iteration number k,which show the efficiency of the proposed method.

关键词： Stochastic differential equations Parareal algorithm Convergence Stochastic Taylor expansion Milstein scheme

First-principles study on electronic structure and optical properties of N-doped P-type β-Ga_2O_3

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Science China(Physics,Mechanics & Astronomy) 2012年第1期55卷 19-24页

作者： zhang liying YAN JinLiang zhang YiJun LI Ting DING XingWei School of Physics Ludong University Yantai 264025 China

The band structure, density of states, electron density difference and optical properties of intrinsic β-Ga2O3 and N-doped β-Ga2O3 were calculated using first-principles based on density functional theory. After N doping, the band gap decreases, shallow acceptor impurity levels are introduced over the top of the valence band and the absorption band edge is slightly red-shifted compared to that of the intrinsic one. The anisotropic optical properties are investigated by means of the complex dielectric function, which are explained by the selection rule of the band-to-band transitions. All calculation results indicate that N-doping is a very promising method to get P-type β-Ga2O3.

关键词： P-type β-Ga2O3 N-doped β-Ga2O3 first-principles electronic structure optical properties

Novel Nanotrees of Crystalline Nickel Formed via Electrolytic Approach

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Nano-Micro Letters 2011年第4期3卷 264-269页

作者： Jian Wang liying zhang Liangming Wei Chuanhai Jiang Yafei zhang Key Laboratory for Thin Film and Microfabrication of the Ministry of Education Research Institute of Micro/Nano Science and TechnologySchool of Materials Science and EngineeringShanghai Jiao Tong University

Tree-shaped nickel nanocrystals with long main trunk and highly ordered branches were prepared via electrolytic method in ethylene glycol solution. The morphology and structures of nanotrees of crystalline nickel can be controlled by the processing of the surfactant(PVP) and electrolytic voltage. Magnetic property measurements at room temperature indicated that the as-prepared nanotrees of crystalline nickel possess higher saturation magnetism(MS) and coercivity(HC) than those of corresponding bulk nickel materials.

关键词： Nickel crystals Nanotrees Hysteresis loop Thermogravimetric analysis

Synthesis of nanosized tungsten powder

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Journal of University of Science and Technology Beijing 2005年第4期12卷 360-364页

作者： Guangfeng Lu Junjie Hao Zhimeng Guo Ruizhu zhang Ji Luo liying zhang Materials Science and Engineering School University of Science and Technology Beijing Beijing 100083 China Department of Mechanical and Engineering North China Institute of Water Conservancy and Hydroelectric Power Zhengzhou 450045 China

Nanosized tungsten powder was synthesized by means of different methods and under different conditions with nanosized WO3 powder. The powder and the intermediate products were characterized using XRD, SEM, TEM, BET （Brunauer Emmett Teller Procedure） and SAXS （X-ray diffracto-spectrometer/Kratky small angle scattering goniometer）. The results show that nanosized WO3 can be completely reduced to WO2 at 600℃ after 40 min, and WO2 can be reduced to W at 700℃ after 90 min, moreover, the mean size of W particles is less than 40 nm. Furthermore, the process of WO3→WO2→W excelled that of WO3→W in getting stable nanosized tungsten powder with less grain size.

关键词： Nano-tungsten powder reduce SAXS

Temporal and spatial variations of low-molecular-weight organic acids in Dianchi Lake, China

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Journal of Environmental Sciences 2011年第8期23卷 1249-1256页

作者： Min Xia Fengchang Wu Runyu zhang liying Wang XinqingLi Rongsheng Huang State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of SciencesGuiyang 550002 China.

Low-molecular-weight organic acids （LMWOAs） in eutrophic lake water of Dianchi, Southwestern China Plateau were investigated diurnally and vertically using ion chromatography. Two profiles （P1 and P2） were studied due to the difference of hydrochemical features. Lactic, formic, pyruvic and oxalic acid were detected as major components at P1 and P2 which were on average 7.98 and 6.53 ~tmol/L, respectively, corresponding to their proportions of 2.68% and 2.48% relative to DOC. Pyruvic acid was regarded as the uppermost species at P1 and P2, reaching up to 3.82 and 3.35 μmol/L and accounting for 47.9% and 51.3%, respectively, in individual TOA. Although humus were of biogenetic production at both sites, the significant negative correlation between diurnal variations of TOAs, fluorescence intensity （FI） of protein-like components and humic-like components at P1 indicated LMWOAs were greatly originated from bacterioplankton excretion and degradation. However, correlations between diurnal variations of humic-like FI and physicochemical parameters demonstrated algal origination of LMWOAs at P2. Although content of humus was high, TOA at P2 was 1.45 ~tmol/L lower than that at P1, due to the co-influence of more intense photo-oxidation and aggregation at P2. Therefore, TOAs exhibited quite opposite diurnal variation trends of increasing-decreasing and decreasing-increasing at P1 and P2, respectively. Except for impact of solar radiation, bacterial decomposition and assimilation rendered shifts of maximal LMWOAs along water column at P1. Covering with massive algae, UV rays penetrated shallower depth that LMWOAs assembled in surface layer water before 18：00 at P2 and represented decreasing profiles.

关键词： Dianchi Lake, humus, algae solar radiation low-molecular-weight organic acids

Fe_(3)O_(4)@C 3D foam for strong low-frequency microwave absorption

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Journal of Materiomics 2023年第1期9卷 148-156页

作者： Li Wang zhang Chen Xue Wang liying zhang Zongtao zhang Qi Zhao Yanfeng Gao School of Materials Science and Engineering Shanghai UniversityShanghai200444China Shanghai Collaborative Innovation Center for High Performance Fiber Composites Center for Civil Aviation CompositesDonghua UniversityShanghai201620China School of Materials Science and Engineering Zhengzhou UniversityZhengzhou450066China

Low-frequency microwave absorbing materials have been challenging for many ***-dimensional dielectric/magnetic porous materials are beneficial for improving the low-frequency microwave absorbing performance because of natural resonance and improved impedance *** this study,Fe_(3)O_(4)@C 3D foam was prepared by carbothermal reduction method and the microwave attenuation performances and mechanisms were *** adjusting the content of Fe_(3)O_(4)@C 3D foam in paraffin composites,the low-frequency microwave attenuation capacity could be effectively *** minimum reflection loss(RLmin)of paraffin composite with 40%(in mass fraction)loading exhibits-54.7 dB at 4.1 GHz for a thickness of 4.0 ***,the paraffin composite with 50%(in mass fraction)loading could almost cover 2–4 GHz(S-band)in the thickness range of 3.5–5.5 *** strong low-frequency microwave attenuation property of Fe_(3)O_(4)@C 3D foam is mainly attributed to excellent low-frequency impedance matching,natural resonance,interfacial/dipole polarization,multiple reflection and *** method provides a new perspective for preparing lightweight and high performance low-frequency microwave absorbing materials.

关键词： Fe_(3)O_(4)@C 3D foam Low-frequency microwave absorption