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Cold-temperature deformation of nano-sized tungsten and niobium as revealed by in-situ nano-mechanical experiments

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Science China(Technological Sciences) 2014年第4期57卷 652-662页

作者： LEE Seok-Woo CHENG YinTong RYU Ill GREER Julia R. division of engineering and Applied Science California Institute of Technology School of engineering Brown University

We constructed and developed an in-situ cryogenic nanomechanical system to study small-scale mechanical behavior of materials at low temperatures. Uniaxial compression of two body-centered-cubic （bcc） metals, Nb and W, with diameters between 400 and 1300 rim, was studied at room temperature and at 165 K. Experiments were conducted inside of a Scanning Electron Microscope （SEM） equipped with a nanomechanical module, with simultaneous cooling of sample and diamond tip. Stress-strain data at 165 K exhibited higher yield strengths and more extensive strain bursts on average, as compared to those at 298 K. We discuss these differences in the framework of nano-sized plasticity and intrinsic lattice resistance. Dislocation dynamics simulations with surface-controlled dislocation multiplication were used to gain insight into size and temperature effects on deformation of nano-sized bcc metals.

关键词： dislocation plasticity metal nanopillar cryogenics

Bitmap lattice index in road networks

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Journal of Central South University 2014年第10期21卷 3856-3863页

作者： Doohee Song Keun-Ho Lee Kwangjin Park Information Communication engineering Wonkwang University division of Information Communication engineering Baekseok University

A novel technique called the bitmap lattice index(BLI) is proposed, which combines the advantages of a wireless broadcasting environment with a road network. Existing road networks are based on the on-demand method: a server's workload increases as the query request increases when a server sends a client information. To solve this problem, we propose the BLI. The BLI denotes an object and a node as 0 and 1 in the Hilbert curve(HC) map. The BLI can identify the position of a node and an object through bit information; it can also reduce the broadcasting frequency of a server by reducing the size of the index, thereby decreasing the access latency and query processing times. Moreover, the BLI is highly effective for data filtering, as it can identify the positions of both an object and a node. In a road network, if filtering is done via the Euclidean distance, it may result in an error. To prevent this, we add another validation procedure. The experiment is conducted by applying the BLI to kNN query, and the technique is assessed by a performance evaluation experiment.

关键词： road network wireless broadcast spatial query bitmap lattice index(BLI)

Using magnetic nanoparticles to manipulate biological objects

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Chinese Physics B 2013年第9期22卷 29-39页

作者：刘毅高宇徐臣杰 division of Bioengineering School of Chemical and Biomedical EngineeringNanyang Technological University

The use of magnetic nanoparticles （MNPs） for the manipulation of biological objects, including proteins, genes, cellular organelles, bacteria, cells, and organs, are reviewed. MNPs are popular candidates for controlling and probing biological objects with a magnetic force. In the past decade, progress in the synthesis and surface engineering of MNPs has further enhanced this popularity.

关键词： magnetic nanoparticles manipulation biological objects

Distinct synergetic effects in the ozone enhanced photocatalytic degradation of phenol and oxalic acid with Fe^(3+)/TiO_2 catalyst

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Chinese Journal of Chemical engineering 2018年第7期26卷 1528-1535页

作者： Yongbing Xie Yingying Chen Jin Yang Chenming Liu He Zhao Hongbin Cao Beijing engineering Research Center of Process Pollution Control Division of Environment Technology and Engineering Institute of Process Engineering Chinese Academy of Sciences

In this work. phenol and oxalic acid （OA） degradation in an ozone and photocatalysis integrated process was intensively conducted with Fe3 ＋/TiO2 catalyst. The ferrioxalate complex formed between Fe3＋ and oxalate accelerated the removal of OA in the ozonation, photolysis and photocatalytic ozonation process, for its high reactivity with ozone and UV. Phenol was degraded in ozonation and photolysis with limited TOC removal rates, but much higher TOC removal was achieved in photocatalytic ozonation due to the generation of-OH. The sequence of UV light and ozone in the sequential process also influences the TOC removal, and ozone is very powerful to oxidize intermediates catechol and hydroquinone to maleic acid. Fenton or photo-Fenton reactions only played a small part in Fe3＋/TiO2 catalyzed processes, because Fe＋ was greatly reduced but not regenerated in many cases. The synergetic effect was found to be highly related with the property of the target pollutants. Fe3 ＋/TiO2 catalyzed system showed the highest ability to destroy organics, but the TiO2 catalyzed system showed little higher synergy.

关键词： Catalysis Environment Waste water Fe3 +/TiO2 Synergistic effect Photocatalytic ozonation

Numerical Study on Air Turbines with Enhanced Techniques for OWC Wave Energy Conversion

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China Ocean engineering 2017年第5期31卷 517-527页

作者： CUI Ying HYUN Beom-Soo KIM Kilwon Department of Ocean engineering College of EngineeringOcean University of China division of Naval Architecture and Ocean engineering Korea Maritime and Ocean University

In recent years,the oscillating water column(OWC) wave energy converter,which can capture wave energy from the ocean,has been widely applied all over the *** the essential part of the OWC system,the impulse and Wells turbines are capable of converting the low pressure pneumatic energy into the mechanical shaft *** an enhanced technique,the design of endplate or ring attached to the blade tip is investigated numerically in this paper.3 D numerical models based on a CFD-software FLUENT 12.0 are established and validated by the corresponding experimental results from the reports of Setoguchi et al.(2004) and Takao et al.(2001).Then the flow fields and non-dimensional evaluating coefficients are calculated and analyzed under steady *** show that the efficiency of impulse turbine with ring can reach up to 0.49 when Ф=1,which is 4% higher than that in the cases for the endplate-type and the original *** the ring-type Wells turbine with fixed guide vanes shows the best performance with the maximal efficiency of 0.55,which is 22% higher than that of the original *** addition,the quasi-steady analysis is used to calculate the mean efficiency and output-work of a wave cycle under sinusoidal flow *** all together,this study provides support for structural optimization of impulse turbine and Wells turbine in the future.

关键词： OWC impulse turbine Wells turbine CFD endplate ring quasi-steady analysis

Emotional inference by means of Choquet integral and λ-fuzzy measurement in consideration of ambiguity of human mentality

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Journal of Central South University 2016年第1期23卷 160-168页

作者： KWON Il-kyoung LEE Sang-yong division of Computer Science & engineering Kongju National University Department of Computer Science & engineering Kongju National University

Research on human emotions has started to address psychological aspects of human nature and has advanced to the point of designing various models that represent them quantitatively and systematically. Based on the findings, a method is suggested for emotional space formation and emotional inference that enhance the quality and maximize the reality of emotion-based personalized services. In consideration of the subjective tendencies of individuals, AHP was adopted for the quantitative evaluation of human emotions, based on which an emotional space remodeling method is suggested in reference to the emotional model of Thayer and Plutchik, which takes into account personal emotions. In addition, Sugeno fuzzy inference, fuzzy measures, and Choquet integral were adopted for emotional inference in the remodeled personalized emotional space model. Its performance was evaluated through an experiment. Fourteen cases were analyzed with 4.0 and higher evaluation value of emotions inferred, for the evaluation of emotional similarity, through the case studies of 17 kinds of emotional inference methods. Matching results per inference method in ten cases accounting for 71% are confirmed. It is also found that the remaining two cases are inferred as adjoining emotion in the same section. In this manner, the similarity of inference results is verified.

关键词： fuzzy measure fuzzy integral emotional model emotion space AHP fuzzy inference system Choquet integral

Temperature Distribution and Thermal Stresses in Various Conditions of Moving Heating Source during Line Heating Process

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Journal of Thermal Science 2012年第1期21卷 82-87页

作者： Yoon Hwan Choi Yeon Won Lee Kwang Choi Deog Hee Doh Kyoung Joon Kim Department of Mechanical and Automotive engineering Pukyong National University Steel Structure Research division Research Institute of Industrial Science & Technology division of Mechanical and information engineering Korea Maritime University

Line heating method is widely used to manufacture curved surfaces in ship building. The main factors governing the quality of the manufactured products are the moving velocity of the heating source, heating strength, and heating ways. In this study, the temperature distributions of the heated plate were investigated with the condition that the line heating process was automatic. The temperature variations were also investigated with the changes of those three variables. The numerical results showed that the peak temperature decreased as the moving velocity of the heating source increased. It also revealed that the peak temperatures changed linearly with the changes of the heating source.

关键词： Moving heat source Line heating Thermal stress Residual deformation Conductive heat transfer

Turbulent structure in uniform inclined open channel flow over different rough porous beds

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International Journal of Sediment Research 2017年第1期32卷 45-52页

作者： Evangelos Keramaris University of Thessaly Department of Civil EngineeringDivision of Hydraulic and Environmental Engineering

In this study the effects of the different rough porous beds in an open inclined channel are studied experimentally for impermeable and permeable porous *** the simulation of porous bed two different types of permeable bed with the same thickness(s’ = 3 cm) and the same porosity ε=0.70 are used:(a) porous filters and(b) gravel *** experiments were used for the calculation of turbulent velocity *** of velocity were taken for inclined channel for three different slopes(S=-0.002,S=-0.004 and S=-0.006) and for five different flow depths(h=5 cm,7 cm,9 cm,11 cm and 13 cm).The total discharge Q varies from 0.78 to 1.31 1/*** measurements were obtained using a two-dimensional(2D) Particle Image Velocimetry(PIV).The total discharge was estimated using a calibrated venture *** showed that the presence of rough porous bed in inclined open channels influence significantly the turbulent characteristics of the flow in comparison with impermeable open channels with the same slopes.

关键词： Particle image velocimetry Porous filters Gravel bed Channel slope Turbulent characteristics

Corrosion and optimum corrosion protection potential of friction stir welded 5083-O Al alloy for leisure ship

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中国有色金属学会会刊：英文版 2009年第4期19卷 898-903页

作者： Sung-Hyeon PARK Jong-Shin KIM Min-Su HAN Seong-Jong KIM division of Maritime Transportation System Mokpo Maritime University Korea Register of Shipping division of Marine engineering Mokpo Maritime University

Electrochemical tests were undertaken to determine the optimum conditions in seawater for corrosion protection of friction stir-welded 5083-O Al *** trend observations show that the limiting potential that avoids the effects of hydrogen embrittlement is -1.6 V,corresponding to the crossover point between concentration polarization and activation ***,the optimum protection potential is between -1.5 and -0.7 V since the current density at these values is low in the potentiostatic *** a galvanic cell is formed in the seawater,the welds exhibit electrochemically stable *** parts in galvanic tests with various area ratios are stable and have excellent anticorrosion characteristics.

关键词：搅拌摩擦焊接保护电位海水腐蚀铝合金氧铝船舶休闲防腐