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Application of unmanned underwater vehicles in polar research

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Advances in Polar Science 2021年第3期32卷 173-184页

作者： ZENG Junbao LI Shuo liu ya State Key Laboratory of Robotics Shenyang Institute of AutomationChinese Academy of SciencesShenyang 110016China Institutes for Robotics and Intelligent Manufacturing Chinese Academy of SciencesShenyang 110169China University of Chinese Academy of Sciences Beijing 100049China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China

The importance of polar ice as vital components of the global ocean-climate system is widely *** this paper,we demonstrate the importance and urgency of polar research,describe the primary characteristics of sea ice and ice shelves,and outline the current status and difficulties associated with sub-ice *** highlight the importance of Unmanned Underwater Vehicles(UUVs)as important tools for oceanographic *** present recent progress in UUV deployment in sub-ice research in the Arctic and the Antarctic,and review the latest international developments in UUV structure,navigation,payload,and field ***,Chinese polar UUVs and their deployments in the polar regions are presented in *** technologies and solutions regarding polar application of UUVs(e.g.,sub-ice navigation and positioning,energy supply and data transmission,and sub-ice guidance and recovery)are *** the current worldwide attention on polar science,the potential future directions of UUV-related polar research(e.g.,observations under Antarctic ice shelves,long-range surveys beneath Arctic sea ice and application of intelligent technology)are discussed.

关键词： unmanned underwater vehicle polar ocean scientific investigation key technologies development trend

A GENERALIZED EXPLICIT SOLUTION OF THE SEQUENT DEPTH RATIO FOR THE HYDRAULIC JUMP

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Journal of Hydrodynamics 2005年第5期17卷 596-600页

作者： NI Han-gen liu ya-kun State Key Laboratory of Coastal and Offshore Enginccring Dalian University of Technology Dalian 116024 China

By use of the property of the momentum equation describing the hydraulic jump in rectangular channels, a generalized solution of the sequent depth ratio was given. On the basis of the generalized solution the explicit solutions of the sequent depth ratio were obtained for the hydraulic jump in gradual enlargements, the corresponding relative energy losses were also presented, and a method to determine the location of hydraulic jump in gradual enlargements was proposed.

关键词： cubic algebraic equation hydraulic jump sequent depth ratio jump in gradual enlargement

Thermoelectric Properties of Mg_2Si_(1-x)Sn_x Synthesized by Bulk Mechanical Alloying

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Chinese Journal of Aeronautics 2006年第B12期19卷 134-138页

作者： SONG Ren-bo liu ya-zheng Tatsuhiko AIZAWA School of Material Science and Engineering University of Science and Technology Beijing Beijing 100083 China Jayram Office University of Toronto Shanghai International Building 6F 1-24-12 Shinkawa Chuo-ku Tokyo 104-0033 Japan

Bulk mechanical alloying （BMA） has been successfully applied to solid-state synthesis of p-type and n-type thermoelectric materials Mg2Si1-xSnx （x = 0, 0.2, 0.4, 0.6, 0.8, 1） from element-powders at the room temperature in a relatively short time. The electrical conductivity, the Seebeck coefficient and the thermal conductivity of the Mg2Si1-xSnx are quite sensitive to the x-content. With the x-content rising, the electrical conductivity increases. When x = 0.6, it reaches the lowest and Mg2Si shows an n-type of semi-conducting However, when x = 0.2 and T 〉525 K, the Seebeck coefficient of the samples will change the opposite way. While x≥0.4, the samples present a p-type of semi-conducting. The figure of merit, Z of Mg2Si1-xSnx will be obtained in the range from 300 K to 700 K. When x = 0.6, Z proves to be higher than that of other samples at 300 K≤ T≤650 K.

关键词： solid-state synthesis thermoelectric bulk mechanical alloying Mg2Si1-xSnx

Dynamics and measurement of cavitation bubble

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Science China(Physics,Mechanics & Astronomy) 2006年第4期49卷 385-395页

作者： CHEN Weizhong liu ya'nan HUANG Wei GAO Xianxian Key Laboratory of Modern Acoustics and Institute of Acoustics Nanjing University Nanjing 210093 China Key Laboratory of Modern Acoustics and Institute of Acoustics Nanjing University Nanjing 210093 China Key Laboratory of Modern Acoustics and Institute of Acoustics Nanjing University Nanjing 210093 China Key Laboratory of Modern Acoustics and Institute of Acoustics Nanjing University Nanjing 210093 China

Based on the introduction of international progress, our investigations on acoustic cavitation have been reported. Firstly we considered the cavity's dynamics under the drive of the asymmetrical acoustic pressure. An aspheric dynamical model was proposed and a new stable and aspheric solution was found in numerical simulation of the theoretical framework of the aspheric model. Then, a dual Mie-scattering technique was developed to measure the cavity's aspheric pulsation. A significant asynchronous pulsation signal between two Mie-scattering channels was caught in the case of large cavity driven by low acoustic pressure. As a direct deduction, we observed an evidence of cavity's aspheric pulsation. Furthermore, we studied the dependency of the asynchronous pulsation signal on the various parameters, such as the amplitude and frequency of the driving acoustic pressure, and the surface tension, viscosity and gas concentration of the liquid. Finally, we introduced a new numeric imaging technique to measure the shapes of the periodic pulsation cavities. The time-resolution was in the order of 20 ns, one order of magnitude lower than that in the previous work, say, 200 ns.

关键词： cavitation, dynamics of cavitation bubble, sonoluminescence.

θ-improved limited tolerance relation model of incomplete information system for evaluation of water conservancy project management modernization

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Water Science and Engineering 2013年第4期6卷 469-477页

作者： Yu-qin GAO Guo-hua FANG ya-qin liu College of Water Conservancy and Hydropower Engineering Hohai University

The modernization of water conservancy project management is a complicated engineering system involving a management system, a management method, management personnel, the exertion of social, economic, and ecological effects, and so on. However, indices for evaluating the modernization of water conservancy project management are usually unobtainable in practical applications. Conducting appropriate extension of the classical rough set theory and then applying it to an incomplete information system are the key to the application of the rough set theory Based on analysis of some extended rough set models in incomplete information systems, a rough set model based on the θ-improved limited tolerance relation is put forward. At the same time, upper approximation and lower approximation are defined under this improved relation. According to the evaluation index system and management practices, the threshold for θ is defined. An example study indicates the practicability and maneuverability of the model.

关键词： Key words: modernization of water conservancy project management O-improved limitedtolerance relation model," upper and lower approximations," threshold

An Efficient Inexact Newton-CG Algorithm for the Smallest Enclosing Ball Problem of Large Dimensions

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Journal of the Operations Research Society of China 2016年第2期4卷 167-191页

作者： ya-Feng liu Rui Diao Feng Ye Hong-Wei liu State Key Laboratory of Scientific and Engineering Computing Institute of Computational Mathematics and Scientific/Engineering ComputingAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China Department of Applied Mathematics Xidian UniversityXi’an 710071China

In this paper,we consider the problem of computing the smallest enclosing ball(SEB)of a set of m balls in Rn,where the product mn is *** first approximate the non-differentiable SEB problem by its log-exponential aggregation function and then propose a computationally efficient inexact Newton-CG algorithm for the smoothing approximation problem by exploiting its special(approximate)sparsity *** key difference between the proposed inexact Newton-CG algorithm and the classical Newton-CG algorithm is that the gradient and the Hessian-vector product are inexactly computed in the proposed algorithm,which makes it capable of solving the large-scale SEB *** give an adaptive criterion of inexactly computing the gradient/Hessian and establish global convergence of the proposed *** illustrate the efficiency of the proposed algorithm by using the classical Newton-CG algorithm as well as the algorithm from Zhou et al.(Comput Optim Appl 30:147–160,2005)as benchmarks.

关键词： Smallest enclosing ball Smoothing approximation Inexact gradient Inexact Newton-CG algorithm Global convergence

Quasicrystal dissolution and performance of isothermally heat-treated Mg–Zn–Y alloy

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Rare Metals 2015年第7期34卷 452-456页

作者： Di-Qing Wan Xian Luo ya-Juan liu Tian Yu Key Laboratory of Ministry of Education for Conveyance and Equipment East China Jiaotong University State Key Laboratory of Solidification Processing Northwestern Polytechnical University School of Materials Science Northwestern Polytechnical University

Conventional casting method was employed to prepare Mg–Zn–Y alloy only with a-Mg+I-phase; however, the grain size of quasicrystal is quite large in the ascast ***, isothermal treatment was applied to refine the quasicrystal *** result shows that after the Mg–Zn–Y alloy was isothermally treated at 500 °C for several hours, the coarse quasicrystal can be gradually dissolved and thus ***, the dissolving processes of quasicrystal are slow first and then accelerate;after isothermally treated with 8 h at 500 °C, the quasicrystal is almost completely dissolved into the matrix only with 1–5 lm tiny quasicrystals *** of quasicrystal can markedly reduce the wear resistance, but increase the corrosion resistance.

关键词： Magnesium alloy Quasicrystal Isothermal treatment

Applications of chitosan-based biomaterials:a focus on dependent antimicrobial properties

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Marine Life Science & Technology 2020年第4期2卷 398-413页

作者： Zhenwei Deng Ting Wang Xiguang Chen ya liu College of Marine Life Science Ocean University of ChinaQingdao 266003China Qingdao National Laboratory for Marine Science and Technology Qingdao 266000China

Marine-derived chitosan has been widely examined for its use in developing biomedical *** only is it non-toxic,biocompatible,and degradable,it has also shown unique antimicrobial *** antimicrobial properties of chitosan are restricted by neutral and physiological conditions because it is insoluble in water and its pKa values is *** solution to this problem is to graft chemically modified groups onto the backbone of *** aim of this paper is to review the mode of antimicrobial action of chitosan and chitosan *** chitosan alone may not meet the demands of various ***,the introduction of additional polymers and antimicrobial agents is commonly used to enhance the antimicrobial potential of chitosan-based ***-based composite biomaterials have been developed that allow diversified formulations to broaden applications,including nanoparticles,hydrogels,films,sponges,fibers,or even *** along with recent advances on chitosan-based composite biomaterials used for wound healing,food packaging,textile sector,3D printing and dental materials,were reviewed in detail.

关键词： Chitosan Derivatives Antimicrobial Wound Food packaging Textile

Lycopene exerts anti-inflammatory effect to inhibit prostate cancer progression

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Asian Journal of Andrology 2019年第1期21卷 80-85页

作者： Li-Ning Jiang ya-Bin liu Bing-Hui Li Department of Surgery II Fourth Hospital of Hebei Medical UniversityShijiazhuang 050011China Department of Urology Surgery I Cangzhou Central Hospita Cangzhou 061000China

Lycopene is a natural compound that alleviates oxidative stress and inflammation,exerting therapeutic effects in a number of *** aim of this study is to investigate the efficacy of lycopene in inhibiting prostate *** viability assays indicated the dose-and time-dependent toxicity of lycopene in prostate cancer *** V/propidium iodide double-staining assays revealed the strong apoptotic effects of *** levels of inflammatory factors,including interleukin-1 (ILl),IL6,ILS,and tumor necrosis factor-α(TNF-α),in lycopene-treated cells were also reduced by lycopene *** the increasing dose of lycopene,the survival of mice bearing prostate cancer xenografts was significantly improved (P <0.01),and the tumor burden was significantly reduced (P <0.01).Our results indicate that lycopene is a promising chemotherapy drug,which inhibits prostate cancer progression by suppressing the inflammatory response.

关键词： dietary supplement inflammation lycopene prostate cancer