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New breakthrough:Building non-markovian environments for single-qubit systems at any time interval

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Science China(Physics,Mechanics & Astronomy) 2025年

作者： H. z. shen Center for Quantum Sciences and School of Physics Northeast Normal University

The proposal of quantum simulation provides a highly effective approach for experimental research on open quantum systems. To date, numerous quantum simulation studies pertaining to open quantum systems have been put forward,including Fanchini et al.’s simulation of a dephasing noise channel utilizing an optical system[1], and Xiong et al.’s realization of a quantum simulation for a non-rotating-wave approximation noise channel, also leveraging an optical system[2].

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OXIDATION BEHAVIOR OF KOVAR ALLOY IN CONTROLLED ATMOSPHERE

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Acta Metallurgica Sinica(English Letters) 2008年第6期21卷 409-418页

作者： D. w. Luo z.S. shen School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

Controlled oxidation experiments were performed on Kovar alloy by changing oxidation atmosphere, temperature, and exposure time to produce films with different oxide type and thickness. The results indicated that single Fe3O4 and single FeO were respectively obtained when Kovar alloy was oxidized in N2-2.31%H2O-0.95%H2 at 500℃ and in N2-2.31%H2O-0.5%H2 at 1000℃, and all kinetic curves followed linear relation; mixed oxides of FeO and Fe3O4 formed when Kovar was oxidized in N2-2.31%H2O at 1000℃and parabolic kinetics were obeyed. Analysis of metallographic cross section of oxides indicated that oxygen diffusion inward through the oxide scale is responsible for intergranular oxide, which had formed beneath the oxide scales when the oxide products were mixed oxides of FeO and Fe3O4, and which did not occur when the oxide was single FeO or Fe3O4. The oxidation model was also established.

关键词： Kovar alloy, Oxidation Controlled atmosphere H2-H2O-N2

A FAMILY OF DIFFERENCE SCHEMES wITH FOURNEAR-CONSERVED QUANTITIES FOR THE KdV EQUATION

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Journal of Computational Mathematics 1998年第2期16卷 129-140页

作者： Han, z shen, LJ No Jiaotong Univ Dept Comp Sci & Technol Beijing 100044 Peoples R China Inst Appl Phys & Computat Math Beijing 100088 Peoples R China

we construct and analyze a family of semi-discretized difference schemes with two parameters for the Korteweg-de Vries (KdV) equation. The scheme possesses the first four near-conserved quantities for periodic boundary conditions. The existence and the convergence of its global solution in Sobolev space L-infinity(0,T;H-3) are proved and the scheme is also stable about initial values. Furthermore, the scheme conserves exactly the first two conserved quantities in the special case.

关键词： convergence difference scheme KdV equation conserved quantity

Transient Characteristics and Accommodative Current Limiting Strategy for Bidirectional Interlinking Converters in Hybrid AC/DC Microgrids

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CSEE Journal of Power and Energy Systems 2024年第4期10卷 1575-1588页

作者： Xia shen zhikang Shuai wen Huang Chao shen Yang shen z.John shen College of Electrical and Information Engineering Hunan UniversityChangsha 410082China Department of Electrical and Computer Engineering Illinois Institute of TechnologyChicagoIL 60616 USA

Bidirectional interlinking converter(BIC)is the core equipment in a hybrid AC/DC microgrid connected between AC and DC ***,the variety of control modes and flexible bidirectional power flow complicate the influence of AC faults on BIC itself and on DC sub-grid,which potentially threaten both converter safety and system *** study first investigates AC fault influence on the BIC and DC bus voltage under different BIC control modes and different pre-fault operation states,by developing a mathematical model and equivalent sequence ***,based on the analysis results,a general accommodative current limiting strategy is proposed for BIC without limitations to specific mode or operation *** amplitude is predicted and constrained according to the critical requirements to protect the BIC and relieving the AC fault influence on the DC bus *** with conventional methods,potential current limit failure and distortions under asymmetric faults can also be ***,experiments verify feasibility of the proposed method.

关键词： Bidirectional interlinking converter current limiting fault characteristic hybrid AC/DC microgrid variation/oscillation of DC bus voltage

COMPARISON OF MATERIAL FOR ENCAPSULATING MINIMODULES

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Acta Metallurgica Sinica(English Letters) 2005年第3期18卷 380-384页

作者： z.zhang H.shen X.Q.Xu w.Chen GuangzhouInstituteofEnergyConversion TheChineseAcademyofSciencesGuangzhou510070China GuangzhouInstituteofEnergyConversion TheChineseAcademyofSciencesGuangzhou510070China／／TheSchoolofPhysicsandEngineeringZhongshanUniversityGuangzhou510640China

The main characteristics of glass, polymethyl methacrylate (PMMA) and polycarbon ate (PC) were presented. The transmittance of glass, PMMA and PC was measured by the UV-VIS spectroscopy analysis. PMMA and PC have the advantages of higher tra nsparency, higher resistance and lower density. It is indicated that both PMMA a nd PC are suitable for encapsulating solar minimodules.

关键词： solar module PMMA PC encapsulate

Surface wettability and Chemistry of Ozone Perfusion Processed Porous Collagen Scaffold

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Journal of Bionic Engineering 2011年第3期8卷 223-233页

作者： Chaozong Liu Shirley z. shen 乙hiwu Han School of Mechanical and Systems Engineering University of Newcastle Newcastle upon Tyne NEI 7R U UK Polymer Composite & Nanomaterials CSIRO Manufacturing & Infrastructure Technology Highett Vic 3190 Australia Key Laboratory of Bionic Engineering (Ministry of Education China) Jilin University Changchun 130022 P. R. China

Crosslinking treatment of collagen has often been used to improve the biological stability and mechanical properties of 3D porous collagen scaffolds. However, accompanying these improvements, the collagen fibril surface becomes hydrophobic nature resulting in a reduced surface wettability. The wetting of the collagen fibril by culture medium is reduced and it is difficult for the medium to diffuse into the 3D structure of a porous collagen scaffold. This paper reports a ＂perfusion processing＂ strategy using ozone to improve the surface wettability of chemical crosslinked collagen scaffolds. Surface wettability, surface composition and biological stability were analyzed to evaluate the effectiveness of this surface processing strategy. It was observed that ozone perfusion processing improved surface wettability for both exterior and interior surfaces of the porous 3D collagen scaffold. The improvement in wettability is attributed to the incorporation of oxygen-containing functional groups onto the surface of the collagen fibrils, as confirmed by X-ray Photoelectron Spectroscopy （XPS） analysis. This leads to a significant improvement in water taking capability without compromising the bulk biological stability and mechanical properties, and confirms that ozone perfusion processing is an effective tool to modify the wettability both for interior and exterior surfaces throughout the scaffold.

关键词： scaffold collagen surface modification hydrophilicity ozone perfusion

SYNTHESIS AND MICROSTRUCTURE OF SUPERHARD TiN/SiN_x MULTILAYER THIN FILMS

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Acta Metallurgica Sinica(English Letters) 2005年第3期18卷 242-248页

作者： z.F.zhou Y.G.shen Y.w.Mai K.Y.Li AdvancedCoatingsAppliedResearchLaboratory（ACARL） DepartmentofManufacturingEngineeringandEngineeringManagementCityUniversityofHongKongKowloonHongKongChina CentreforAdvancedMaterialsTechnology（CAMT） SchoolofAerospaceMechanicalandElectronicEngineeringUniversityofSydneySydneyNSW2006Australia

Multilayer thin films of TiN/SiNx have been deposited onto heated Si 100 substra tes (200℃) by reactive dc-magnetron sputtering from Ti and Si targets in an Ar- N2 gas mixture. The rotation speed of the substrate holder was varied from 1 to 20rpm, while target currents were held constant, to produce bilayer periods vary ing from approximately 22 to 0.6nm. These multilayer films were characterized by atomic force microscopy (AFM), cross-sectional transmission electron microscopy (TEM), scanning electron microscopy (SEM), and microhardness measurements. TEM and SEM studies showed elimination of columnar structure in TiN, owing to the in corporation of amorphous SiNx layers. The crystallinity of TiN and amorphous nat ure of SiNx were confirmed by high resolution TEM. An optimum rotation speed was observed, at which hardness was a maximum. The resulting bilayer period was fou nd to be approximately 1.6nm, which resulted in a significant improvement in mic rohardness (~57GPa). The rms surface roughness for this film was less than 1.5nm .

关键词： multilayers hardness supermodulu s stress TiN/SiNx

Stability Investigation and Improvement for DC Cascade Systems with Simplified Impedance-based Stability Criterion

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1044-1052页

作者： Junbin Fang zhikang Shuai Yang Li zhibing wang Xiangyang wu Xia shen z.John shen College of Electrical and Information Engineering Hunan UniversityChangsha 410082China Renewable Energy Department of China Electric Power Research Institute Beijing 100192China Department of Electrical and Computer Engineering Illinois Institute of TechnologyChicagoIL 60616USA IEEE

In DC distributed power systems(DPSs),the complex impedance interactions possibly lead to DC bus voltage oscillation or *** previous research,the stability analysis of DPSs is implemented based on mathematical analysis in control *** specific mechanisms of the instability of the cascade system have not been intuitively *** this paper,the stability analysis of DPSs based on the traditional Nyquist criterion is simplified to the resonance analysis of the seriesconnected port impedance(z=R+jX)of source and load *** reveals that the essential reason for impedance instability of a DC cascade system is that the negative damping characteristic(Rzero-crossing *** simplified stability criterion for DC cascade systems can be concluded as:in the negative damping frequency ranges(Rzero-crossing point of the reactance component(i.e.,X=0).According to the proposed stability criterion,the oscillation modes of cascade systems are classified.A typical one is the internal impedance instability excited by the negative damping,and the other one is that the external disturbance amplified by negativity in a low stability ***,the impedance reshaping method for stability improvement of the system can be further *** validity of the simplified criterion is verified theoretically and experimentally by a positive damping reshaping method.

关键词： DC cascaded system,impedance model impedance reconstruction stability criterion

In vitro and in vivo studies on pure Mg, Mg-1Ca and Mg-2Sr alloys processed by equal channel angular pressing

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Nano Materials Science 2020年第1期2卷 96-108页

作者： wenting Li Yunong shen Jie shen Danni shen Xiao Liu Yufeng zheng Kelvin w.K.Yeung Shaokang Guan Olga B.Kulyasova R.z.Valiev Department of Materials Science and Engineering College of EngineeringPeking UniversityBeijing100871China College of Materials Science and Engineering University of Science and Technology BeijingBeijing100083China Department of Orthopaedics and Traumatology The University of Hong KongPokfulamHong KongChina School of Materials Science and Engineering Zhengzhou UniversityZhengzhou450001China Ufa State Aviation Technical University 12 Karl Marx StreetUfa450008Russia

In the present work,the biomedical as-cast pure Mg,Mg–1 Ca and Mg–2 Sr alloys were processed with equal channel angular pressing(ECAP)technique to develop ultrafine microstructure within the materials,and their microstructures,mechanical properties,degradation behavior,cytocompatibility in vitro and biocompatibility in vivo were studied ***-gained microstructures and improved mechanical properties of these three materials after ECAP were confirmed compared to their as-cast ***,after ECAP the degradation rate of pure Mg was increased while that of Mg–1 Ca or Mg–2 Sr alloys decreased compared to the ascast ***,good in vitro cytocompatibility and in vivo biocompatibility of these three materials were revealed by cell cultural tests using osteoblastic MC3 T3-E1 and human mesenchymal stem cells(h MSC)and in vivo animal tests at the lateral epicondyle of SD-rats’*** study offers an alternative powerful avenue to achieve good comprehensive properties of magnesium-based biodegradable *** might also help to extend the applied range of magnesium-based biodegradable metals in orthopedic field.

关键词： Magnesium alloys Equal channel angular pressing Mechanical property Degradation behavior Biocompatibility