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Influence of the extraction parameters on the cytotoxicity test results of Mg materials

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Progress in Natural Science:Materials International 2014年第5期24卷 507-515页

作者： xiaoli Liu Tingfei xi Yudong zheng School of Materials Science and Technology University of Science and Technology Beijing Center for Biomedical Materials and Tissue Engineering Academy for Advanced Interdisciplinary Studies Peking University Shenzhen Key Laboratory of human Tissue Regeneration and Repair Shenzhen Institute Peking University

Recently more and more researchers query the predictability of cytotoxicity results of biomedical Mg alloys obtained according to ISO 10993 due to significant difference between in vitro and in vivo corrosion. This study aimed to observe the influence of different extraction parameters(time, volume/surface ratio and medium composition) on cytotoxicity results and illustrate whether more predictable results could be obtained by adjusting the extraction parameters. The results showed that longer extraction time and smaller extraction volume/surface ratio improve the sensitivity of screening Mg materials by making inferior Mg materials release relatively more ions to the extract; and more predictable results could not be obtained by the way of simply adding bovine serum albumin(BSA) into the extraction medium to the same level in vivo or simply using fetal bovine serum(FBS) directly as extraction medium, since BSA and FBS accelerated the corrosion of Mg materials during extraction and they affected the cells’ health states during the test. In order to get more predictable results, in our opinions, it is necessary to establish a database of primary cells’ hazards(metal ions, p H and H2gas) tolerance and a set of in vitro corrosion test with high similarity in vivo, which is very difficult to realize now however.

关键词： Mg alloys Cytotoxicity test Extraction parameters Corrosion Predictability

Multi-agent and ant colony optimization for ship integrated power system network reconfiguration

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Journal of Systems Engineering and Electronics 2022年第2期33卷 489-496页

作者： WANG zheng hu Zhiyuan YANG Xuanfang School of Electrical Engineering Naval University of EngineeringWuhan 430033China

Electric power is widely used as the main energy source of ship integrated power system(SIPS), which contains power network and electric power network. SIPS network reconfiguration is a non-linear large-scale problem. The reconfiguration solution influences the safety and stable operation of the power system. According to the operational characteristics of SIPS, a simplified model of power network and a mathematical model for network reconfiguration are established. Based on these models, a multi-agent and ant colony optimization(MAACO) is proposed to solve the problem of network reconfiguration. The simulations are carried out to demonstrate that the optimization method can reconstruct the integrated power system network accurately and efficiently.

关键词： ship integrated power system(SIPS) multi-agent and ant colony optimization(MAACO) network reconfiguration ring grid fault recovery

Two-Level Linear Clustering Protocol Based on Wireless Sensor Networks

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Journal of Electronic Science and Technology 2016年第3期14卷 257-261页

作者： Mei hu Yong-xi Wang the School of Electronic and Information Engineering Lanzhou Institute of TechnologyLanzhou 730050China

Aiming at the defects of the nodes in the low energy adaptive clustering hierarchy （LEACH） protocol, such as high energy consumption and uneven energy consumption, a two-level linear clustering protocol is built. The protocol improves the way of the nodes distribution at random. The terminal nodes which have not been a two-level cluster head in the cluster can compete with the principle of equivalent possibility, and on the basis of the rest energy of nodes the two-level cluster head is selected at last. The single hop within the cluster and single hop or multiple hops between clusters are used. Simulation experiment results show that the performance of the two-level linear clustering protocol applied to the Hexi corridor agricultural field is superior to that of the LEACH protocol in the survival time of network nodes, the ratio of success, and the remaining energy of network nodes.

关键词： Clustering energy-efficient farmland Hexi corridor low energy adaptive clustering hierarchy (LEACH) linear wireless sensor network (WSN).

New design of large fully-steerable radio telescope reflector based on homogenized mesh structure

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Research in Astronomy and Astrophysics 2021年第10期21卷 27-36页

作者： Li-De Yan Fei zheng xi Rui School of Mechano-Electronic Engineering Xidian UniversityXi'an 710071China

The self-weight of a large fully-steerable radio telescope is one of the important factors affecting its *** the existing reflector system scheme,the problem of surface accuracy caused by its large and heavy structure has seriously restricted the application and implementation of large radio ***,a new mesh structure scheme for a large fully-steerable radio telescope reflector is proposed in this *** scheme is based on a homogenized mesh back-up structure in the form of a quasi-geodesic grid and regular quasi-tri-prism or tetrahedron,which can significantly reduce the structural complexity and self-weight of the reflector under the condition that the reflector can meet the desired performance ***,the feasibility and rationality of the scheme are evaluated by numerical simulation analysis,which has significant advantages and provides a new design for the reflector of a large fullysteerable radio telescope.

关键词： telescopes techniques:radar astronomy methods:data analysis

Dynamic Parameters Cellular Automaton Model for Passengers in Subway

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Tsinghua Science and Technology 2015年第6期20卷 594-601页

作者： Yichen zheng xiangyu xi Yifan Zhuang Yi Zhang Department of Automation Tsinghua National Laboratory for Information Science and Technology (TN List)Tsinghua University National Engineering Research Center of Software Engineering Peking University Tsinghua University

To simulate the passenger behavior in subway system, a Dynamic Parameters Cellular Automaton(DPCA) model is put forward in this paper. Pedestrian traffic flows during waiting, getting on or off, and traveling can be simulated. The typical scenario in Beijing Subway Line 13 is modeled to analyze the passenger behavior in subway system. By comparing simulation results with statistical ones, the correctness and practicality of the DPCA model are verified. At last, the additional results made by DPCA model can make contribution to passenger comfort analysis and pedestrian facility planning and guidance.

关键词： pedestrian stream subway cellular automaton dynami

Probing the interplay between chain diffusion and polymer crystal growth under nanoscale confinement： a study by single molecule fluorescence microscopy

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Science China Chemistry 2018年第11期61卷 1440-1446页

作者： xi Lu Kaikai zheng Jingfa Yang Jiang Zhao Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China

Motions of single poly（c-caprolactone）（PCL） molecules during the formation of the dendrite crystals in ultrathin films are captured by single molecule fluorescence microscopy. The relationship of single molecule diffusion coefficient with the crystal growth rate, together with radius curvature, side-branch spacing of dendrite crystal and morphology are examined. The results support Mullins-Sekerka （MS） instability as the origin of lamellar branching induced by a diffusion field generated by a gradient of polymer segment density ahead of the crystal. Further analysis of the molecular trajectories has recognized different types of motions, depending on the distance to the crystal front： Fickian diffusion in regions far away from the crystal, sub-diffusion in regions adjacent to the crystal, and directed motion between these two regions. Anti-correlation of successive steps is discovered accompanying the sub-diffusion, providing a clear signature of macromolecule crowding at the crystal growth front. This anomalous diffusion process in polymer ultrathin films presents a new insight into the understanding of the retarded dynamics of interfacial mass transport towards the crystal front. It is considered to play a decisive role in controlling the crystal growth and evolution of crystal morphology.

关键词： single molecule imaging fluorescence microscopy polymer crystallization diffusion pattern formation

THE SOLVABILITY CONDITIONS FOR THE INVERSE PROBLEM OF BISYMMETRIC NONNEGATIVE DEFINITE MATRICES

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Journal of Computational Mathematics 2000年第6期18卷 597-608页

作者： Dong-xiu xie Lei Zhang xi-yan hu Department of Applied Mathematics Dalian University of TechnologyDalian 116023China Department of Applied Mathematics Hunan UniversityChangsha 410082China hunan Computing Center Changsha 410012China

A = (a[sub ij]) ∈ R[sup n×n] is termed bisymmetric matrix if a[sub ij] = a[sub ji] = a[sup n ? j + 1, n ? i + 1], i, j = 1, 2 ··· n. We denote the set of all n x n bisymmetric matrices by BSR[sup n x n]. This paper is mainly concerned with solving the following two problems: Problem I. Given X, B ∈ R[sup n×m], find A ∈ P[sub n] such that AX = B, where P[sub n] = {A ∈ BSR[sup n×n]| x[sup T] Ax ≥ 0, ?x ∈ R[sup n]}. Problem II. Given A[sup *] ∈ R[sup n×n], find ? ∈ S[sub E] such that ||A[sup *] - ?||[sub F] = ... ||A[sup *] - A||[sub F] where || · ||[sub F] is Frobenius norm, and S[sub E] denotes the solution set of problem I. The necessary and sufficient conditions for the solvability of problem I have been studied. The general form of S[sub E] has been given. For problem II the expression of the solution has been provided. [ABSTRACT FROM AUTHOR]

关键词： Frobenius norm bisymmetric matrix the optimal solution

Adsorption Behavior of CH2 and CH3 on Metal Clusters CUn （n=1-6）

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Chinese Journal of Chemical Physics 2008年第5期21卷 445-450页

作者： xi-hui Cheng Ming-xing Jin Zhan hu Fei-fei hu Da-jun Ding Institute of Atomic and Molecular Physics Jilin University Changchun 130012 China

Using density functional theory with generalized gradient approximation and hybrid functional, we studied the properties of energy, charge population, and vibration of CH2 and CH3 adsorbed on Cun （n=1-6） clusters. The results show that the DFT calculation with the hybrid functional matches the experimental results better in both cases. The calculation results indicate that the adsorption of CH2 is stronger than that of CH3. During adsorption, the charges transfer from Cu to CH2 or CH3. The obtained vibrational frequencies for different modes of CH2 and CH3 adsorbed on Cun agree well with the experimental results for the adsorption on Cu（111） surface.

关键词： Adsorption CH2 CH3 Cu cluster

Platinum drugs:from Pt(Ⅱ)compounds,Pt(Ⅳ)prodrugs,to Pt nanocrystals/nanoclusters

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Science Bulletin 2017年第8期62卷 589-596页

作者： xi hu Fangyuan Li Nabila Noor Daishun Ling Zhejiang Province Key Laboratory of Anti-Cancer Drug Research College of Pharrnaceutical SciencesZhejiang UniversityHangzhou 310058China Key Laboratory of Biomedical Engineering of the Ministry of Education College of Biomedical Engineering&Instrument ScienceZhejiang UniversityHangzhou 310027China

Platinum(Pt) based drugs, such as cisplatin, are widely used as anti-cancer agents, but their severe adverse reactions and resistance of cancer patients have limited their board clinical use. For the last few decades, Pt(Ⅱ) compounds, Pt(Ⅳ) prodrugs as well as smart drug delivery systems have been developed to overcome these problems. However, most conventional strategies rely on the similar anti-cancer mechanism with cisplatin and consequently only achieve limited success. Recently, Pt nanocrystals/nanoclusters(Pt NCs), with a brand new anti-cancer mechanism, have shown a promising potential in targeted cancer therapy, especially in Pt resistance circumvention. This review is helpful to understand the research strategies of Pt drugs, particularly, the recent developments and medical applications of Pt NCs.

关键词： Platinum Pt(Ⅱ) Pt(Ⅳ) Pt nanocrystals/nanoclusters Pt resistance Cancer therapy