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UPA based 3D visualization of discontinuities in great thickness EBW seam

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china Welding 2016年第2期25卷 1-5页

作者： Sun Changli gang Tie chi Dazhao State Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology Harbin 150001 School of Computer and Information Engineering Heilongjiang University of Science and Technology Harbin150022

Electron beam welding （EBW） is a fusion welding process in which a beam of high-velocity electrons is applied to two materials to be joined. It is a complex high-temperature metallurgical process, and the quality of welding may deteriorate because of defects caused by improper welding parameters, especially in the EBW of thickened aluminum alloy plate. Ultrasonic phased array（UPA） technology has been applied more widely in the field of nondestructive testing because of its ability of effectively controlling the shape and direction of the emitted ultrasonic beam. In present research, a specimen with EBW seam on thickened aluminum plate was tested with a linear array ultrasonic phased array probe, and a large number of B-scan images of the weld were acquired by electronic scanning in probe combined with the mechanical scanning of the probe along the weld direction. This large number of B-scan images were stacked to construct the volume data, with which the 3D image of the weld discontinuities were reconstructed, and the 3D visualization was realized. More details about weld discontinuities＇ spatial distribution and orientation were revealed, and this approach also made the results of non-destructive ultrasonic testing more easily to understand.

关键词： electron beam welding thickened aluminum plate ultrasonic phased array 3D reconstruction 3Dvisualization

Growth and Cd Accumulation of Orychophragmus violaceus as Affected by Inoculation of Cd-Tolerant Bacterial Strains

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Pedosphere 2014年第3期24卷 322-329页

作者： LIANG Xia HE chi-Quan NI gang TANG Gui-E CHEN Xue-Ping LEI Yan-Ru School of Environmental and Chemical Engineering Shanghai University

Beneficial interactions between microorganisms and plants, particularly in the rhizosphere, are a research area of global interest. Four cadmium(Cd)-tolerant bacterial strains were isolated from heavy metal-contaminated sludge and their effects on Cd mobility in soil and the root elongation and Cd accumulation of Orychophragmus violaceus were explored to identify the capability of metalresistant rhizobacteria for promoting the growth of O. violaceus roots on Cd-contaminated soils. The isolated strains, namely, Bacillus subtilis, B. cereus, B. megaterium, and Pseudomonas aeruginosa, significantly enhanced the plant Cd accumulation. The Cd concentrations in the roots and shoots were increased by up to 2.29- and 2.86-fold, respectively, by inoculation of B. megaterium, as compared with the uninoculated control. The bacterial strains displayed different effects on the shoot biomass. Compared with the uninoculated plants, the shoot biomass of the inoculated plants was slightly increased by B. megaterium and significantly decreased by the other strains. B. megaterium was identified as the best candidate for enhancing Cd accumulation in O. violaceus. Thus, this study provides novel insight into the development of plant-microbe systems for phytoremediation.

关键词： heavy metals phytoremediation plant-microbe systems rhizobacteria soil contamination

Material properties of friction stir spot welded joints of dissimilar aluminum alloys

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中国有色金属学会会刊：英文版 2012年第S3期22卷 605-613页

作者： chi-Sung JEON Sung-Tae hong Yong-Jai KWON Hoon-Hwe CHO Heung Nam HAN Technical Research Center Hyundai Steel Company School of Mechanical Engineering University of Ulsan Department of Materials Science and Engineering University of Ulsan Department of Materials Science and Engineering Seoul National University

Mechanical properties and material mixing patterns of friction stir spot welded (FSSW) joints of dissimilar aluminum alloys were *** aluminum alloys typically used in automotive applications,5052-H32 and 6061-T6,were *** the experiment,the process parameters including the z-axis force and torque histories were measured as a function of the tool *** mechanical properties were investigated by microhardness measurements of the joint,and the material mixing in the stir zone was investigated by *** experimental results illustrate different process parameter histories,material mixing in the stir zone and material properties including microhardness distributions for FSSW joints of dissimilar aluminum alloys,likely due to different mechanical behaviors of the selected aluminum alloys in the FSSW process temperature range.

关键词： friction stir spot welding dissimilar aluminum alloys force histories torque histories microhardness

Signals of α clusters in ^(16)O+^(16)O collisions at the LHC from relativistic hydrodynamic simulations

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chinese Physics C 2023年第2期47卷 149-156页

作者：丁驰庞龙刚张松马余刚 Key Laboratory of Quark&Lepton Physics(MOE)and Institute of Particle Physics Central China Normal UniversityWuhan 430079China Key Laboratory of Nuclear Physics and Ion-beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai 200433China Shanghai Research Center for Theoretical Nuclear Physics NSFC and Fudan University Shanghai 200438China

In relativistic heavy ion collisions,the fluctuations of initial entropy density convert to the correlations of final state hadrons in momentum space through the collective expansion of strongly interacting QCD *** a(3+1)D viscous hydrodynamic program,CL Visc,we consider whether the nuclear structure,which provides initial state fluctuations as well as correlations,can affect the final state of heavy ion collisions,and whether one can find signals of α cluster structures in oxygen using final state observables in ^(16)O+ ^(16)O collisions at the CERN Large Hadron *** the initial nucleon distributions in oxygen nuclei,we compare three different configurations,a tetrahedral structure with four-α clusters,the deformed Woods-Saxon distribution,and a spherical symmetric Woods-Saxon *** results show that the charged multiplicity as a function of centrality and the elliptic flow at the most central collisions using the four-α structure differs from those with the Woods-Saxon and deformed Woods-Saxon distributions,which may help to identify α clustering structures in oxygen nuclei.

关键词： alpha cluster heavy ion collisions nuclear structure of oxygen relativistic hydrodynamics

Portfolio optimization based on network centralities:Which centrality is better for asset selection during global crises?

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Journal of Management Science and Engineering 2024年第3期9卷 348-375页

作者： gang-Jin Wang Huahui Huai You Zhu chi Xie Gazi Salah Uddin Business School and Center for Finance and Investment Management Hunan UniversityChangsha410082China Hunan Province Key Laboratory of Philosophy and Social Science of Industrial Digital Intelligence Finance Changsha410082China Department of Management and Engineering Linköping University58183LinköpingSweden Cambridge Centre for Economic and Public Policy(CCEPP) University of CambridgeCambridgeUnited Kingdom

We construct correlation-based networks linking 86 assets(stock indices,bond indices,foreign exchange rates,commodity futures,and cryptocurrencies)and analyze the impact of asset selection on portfolio optimization using different centrality measures(including degree,eigenvector,eccentricity,betweenness,PageRank,and hybrid centralities).In times of a global crisis,peripheral assets located in cross-market networks are more suitable for *** comparing portfolio performance based on different centrality measures,we find that(i)hybrid,eigenvector,and PageRank centralities can best improve portfolio performance;(ii)degree centrality is suitable for larger portfolios;and(iii)eccentricity and betweenness centralities are unsuitable for network optimization *** response,we explain them based on the construction principle of centrality ***,our optimal portfolios suggest that investors pay more attention to the role of emerging countries,which are less exposed to external shocks and whose financial markets are more likely to remain stable.

关键词： Financial network Centrality measures Portfolio optimization Asset selection Global crisis

Physical Insight for Grafting Polymer Chains onto the Substrate via Computer Simulations:Kinetics and Property

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chinese Journal of Polymer Science 2022年第7期40卷 817-833页

作者： chi-Xin Liang Hui Lu Bai-Ying Huang Ji-Yuan Xing Feng-Long Gu hong Liu School of Chemistry South China Normal UniversityKey Laboratory of Theoretical Chemistry of Environment Ministry of EducationGuangzhou510006China State Key Laboratory of Supramolecular Structure and Materials Institute of Theoretical ChemistryCollege of ChemistryJilin UniversityChangchun130023China State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China

Molecules adsorbed or attached on a surface is a quite basic phenomenon in numerous chemical or biological ***-onto is considered as a feasible way to achieve *** grafting reaction is essentially controlled by the diffusion of the molecules,thus it is more likely a physical issue,instead of a chemical *** of the experimental difficulty in measuring the properties of surface-attached molecules(e.g.,the polymeric molecules),the surface-bound molecules are often assumed as with the same properties as that of the start feeding ones in *** assumption was even used to guide further characterization,while it is proved to be invalid by different quantifying ***,an effective prediction for the properties of surface-bound molecules is still *** on a microscopic level and a dynamic perspective,the grafting process onto a flat substrate with polydisperse feeding polymeric molecules is investigated in-depth by coarse-grained Brownian dynamics simulation as well as model *** find from simulations that for the final grafting densityσ_(g)and the mean chain length of start feeding molecules,the dependence ofσ_(g)-^(γ)with the constant exponential factorγmay be a determined rule for one-end functionalized flexible linear polymer chains grafting on the flat *** grafting-onto is a multiple interplayed process,our simulation study indicates that there is an optimized initial concentration of start feeding molecules for achieving high grafting density of surface-bound *** also propose a correctional equation to quantitatively predict the molecular weight distribution(MWD)of surface-bound polymeric molecules,which may be effective for predicting the MWD of the surface-bound ones in specific *** simulation study helps to better understand the kinetics of grafting-onto process,and serves as a theoretical guide to achieve the precise design of surface modification materials vi

关键词： Grafting-onto Grafting density Polydisperse Molecular weight distribution

Optical sensing of explosives in wastewater by competitive complexation

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Progress in Natural Science:Materials International 2019年第6期29卷 655-659页

作者： Jiaxin Niu hong chi Pingxin Gao Zongkuan Liu Xiaohu Yin Zhaolin Gu School of Human Settlement and Civil Engineering Xi'an Jiaotong University Shandong Provincial Key Laboratory of Molecular Engineering School of Chemistry and Pharmaceutical Engineering Qilu University of Technology (Shandong Academy of Sciences)

A facile strategy for optical sensing of explosives with the assistance of 1,3,5-Triazine-2,4,6-triamine（MEL） in aqueous solution is proposed. Upon exposure to MEL, the electron-sufficient amino group in MEL was prone to form complexes with electron-deficient nitro group in explosives. The interaction could be tuned by the amount of MEL to fully consumed nitro-contained explosives dissolved in wastewater, thus prevented the gold nanoparticles（GNPs） from combining with MEL. In comparison with common detection method, the dose-response curve procedure reported here was in good linear relationship from 0 μM to 80 μM with good correlation factor（R;= 0.9871）, and was satisfactorily agreed with the proposed theoretical model. The detection limit（Lo D） was1.1 μM by spectrometer, 3.0 μM visualized by naked eyes and 21.3 nM by calculation. The procedure described in this study could be finished within a few minutes and showed its effectiveness in explosive detection upright on the gold surface in real wastewater, making this proposed method a powerful tool in several sensing platforms.

关键词： Explosive detection Optical sensing Competitive complexation Gold nanoparticles 1,3,5-Triazine-2,4,6-triamine

Immunomodulatory effects of mesenchymal stem cells derived from adipose tissues in a rat orthotopic liver transplantation model

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Hepatobiliary & Pancreatic Diseases International 2008年第1期7卷 29-33页

作者： Wan, chi-Dan Cheng, Rui Wang, hong-Bo Liu, Tao Huazhong Univ Sci & Technol Tongji Med Coll Unino Hosp Dept Gen Surg Wuhan 430022 Peoples R China

BACKGROUND: Acute rejection after liver transplantation is usually treated with large doses of immunosuppressants with severe toxic and side-effects, so it is imperative to find a safe and effective method for preventing and treating rejection. This study was designed to confirm the immunomodulatory effects of rat mesenchymal stem cells (MSCs) in vitro and investigate the tolerogenic features in a rat model of allogeneic liver transplantation. METHODS: MSCs were isolated from adipose tissue of Sprague-Dawley (SD) rats and cultured. In vitro, MSCs were added into a mixed lymphocyte culture (MLC) system to study the inhibitory effects of MSCs on the proliferation of T lymphocytes in Wistar rats. By using SD and Wistar rats as liver donors and recipients, an orthotopic liver transplantation model was established and the rats were divided into a MSC-treated group and a blank control group. On postoperative day 7, all rats were sacrificed, and the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), interleukin-2 (IL-2) and interleukin-10 (IL-10) were measured. The pathological changes of liver tissue and apoptosis of hepatocytes were also assessed. RESULTS: In in vitro MLC, T lymphocyte proliferation in Wistar rats was significantly inhibited by 48.44%. In the MSC-treated group, the levels of ALT, AST, TBIL, IL-2 and IL-10 were 134.2 +/- 45.0 U/L, 162.5 +/- 30.5 U/L, 30.6 +/- 5.4 mu mol/L, 187.35 +/- 18.26 mu g/L and 193.95 +/- 37.62 mu g/L, and those in the blank control group were 355.6 +/- 54.3 U/L, 296.4 +/- 71.2 U/L, 145.7 +/- 28.6 +/- mol/L, 295.73 +/- 57.15 mu g/L and 75.12 +/- 11.23 mu g/L, respectively, with statistically significant differences (P<0.05). Pathological examination revealed that the rejection in the MSC-treated group was clearly alleviated compared with that in the blank control group. TUNEL indicated that the apoptosis of hepatocytes in the MSC-treated group was milder than that in the blank control

关键词： adipose tissue mesenchymal stem cells liver transplantation acute rejection

STRUCTURE EVOLUTION OF POLYMER CHAINS FOR NECKING FORMATION IN HIGH-SPEED FIBER SPINNING PROCESS

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chinese Journal of Polymer Science 2006年第1期24卷 1-11页

作者： hong Zheng Wei Yu hong-bin Zhang and chi-xing Zhou Department of Polymer Materials Science & Engineering,Shanghai Jiao Tong University,Shanghai 200240,china Shanghai Jiao Tong Univ Dept Polymer Mat Sci & Engn Shanghai 200240 Peoples R China

Finite element method is used to simulate the high-speed melt spinning process, based on the equation system proposed by Doufas et al. Calculation predicts a neck-like deformation, as well as the related profiles of velocity, diameter, temperature, chain orientation, and crystallinity in the fiber spinning process. Considering combined effects on the process such as flow-induced crystallization, viscoelasticity, filament cooling, air drag, inertia, surface tension and gravity, the simulated material flow behaviors are consistent with those observed for semi-crystalline polymers under various spinning conditions, The structure change of polymer coils in the necking region described by the evolution of conformation tensor is also investigated. Based on the relaxation mechanism of macromolecules in flow field different types of morphology change of polymer chains before and in the neck are proposed, giving a complete prospect of structure evolution and crystallization of semi-crystalline polymer in the high speed fiber spinning process.

关键词： Semi-crystalline Polymer Crystallization High-speed Fiber Spinning Process Conformation Finite Element Method (FEM).