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ON THE L_∞ CONVERGENCE AND THE EXTRAPOLATION METHOD Of.A DIf.ERENCE SCHEME f.R NONLOCAL PARABOLIC EQUATION WITH NATURAL BOUNDARY CONDITIONS

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Journal of.Computational Mathematics 2001年第5期19卷 449-458页

作者： wan, z.-S. Sun, z.-z. Institute of.Applied Physics and CM P.O. Box 8009 Beijing 100088 China

In paper (J. Comput. Appl. Math., 76 (1996), 137-146), a dif.erence scheme f.r a class of.nonlocal parabolic equations with natural boundary conditions was derived by the method of.reduction of.order and the unique solvability and second order convergence in L2-norm are proved. In this paper, we prove that the scheme is second order convergent in L∞ norm and then obtain f.urth order accuracy approximation in L∞ norm by extrapolation method. At last, one numerical example is presented.

关键词： Approximation theory Boundary conditions Convergence of.numerical methods Extrapolation

A method f.r analyz.ng on-line video images of.crystalliz.tion at high-solid concentrations

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Particuology 2008年第1期6卷 9-15页

作者： Jian wan Cai Y. Ma Xue z. wang Institute of.Particle Science and Engineering School of Process Environmental and Materials Engineering University of Leeds Leeds LS2 9JT UK

Recent research has demonstrated that on-line video imaging is a very promising technique f.r monitoring crystalliz.tion processes. The bottleneck in applying the technique f.r real-time closed-loop control is considered as image analysis that needs to be robust, f.st and able to handle varied image qualities due to temporal variations of.operating conditions such as mixing and solid concentrations. Image analysis at highsolid concentrations turns out to be extremely challenging because crystals tend to overlap or attach to each other and the boundaries between the crystals are usually ambiguous. This paper presents an image segmentation algorithm that can ef.ectively deal with images taken at high-solid concentrations. The method segments crystals attached to each other along the mostly related concave points on the contours of.crystal blocks. The detailed procedure is introduced with application to crystalliz.tion of.L-glutamic acid in a hot-stage reactor.

关键词： Crystalliz.tion High-solid concentrations Image processing Multi-scale segmentation Watershed segmentation Crystal siz. distribution

f.iction and wear behaviors of.a gradient nano-grained AISI 316L stainless steel under dry and oil-lubricated conditions

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Journal of.Materials Science & Technology 2018年第10期34卷 1835-1842页

作者： P.f. wang z. Han Shenyang National Laboratory f.r Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China University of.Chinese Academy of.Sciences Beijing 100049 China

A gradient nano-grained （GNG） surf.ce layer was f.bricated on an AIS1316L stainless steel （SS） by using the surf.ce mechanical rolling treatment （SMRT）. Reciprocating dry and oil-lubricated sliding tests of.the GNG 316L SS in air at room temperature were conducted in comparison with the coarse-grained （CG） counterpart. Worn surf.ce morphologies and subsurf.ce microstructures were investigated f.r both 316L SS samples. 316L SS with a GNG surf.ce layer shows a signif.cantly improved wear resistance, especially under oil-lubricated condition. The notably wear resistance enhancement of.the GNG 316L SS is attributed to the GNG surf.ce layer with high strain accommodation ability and high hardness, which can reduce the wear volume in the running-in stage ef.ectively.

关键词： Austenitic stainless steel Gradient nano-grained surf.ce layer f.iction and wear Running-in

Evaluation of.the inf.ctivity,gene and antigenicity persistence of.rotaviruses by f.ee chlorine disinf.ction

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Journal of.Environmental Sciences 2011年第10期23卷 1691-1698页

作者： Dan Li April z. Gu Siyu z.ng wan Yang Miao He Hanchang Shi Environmental Simulation and Pollution Control （ESPC） State Key Joint Laboratory School of Environment Tsinghua University Beijing 100084 China Department of.Civil and Environmental Engineering Northeastern University Boston MA 02115 USA

The ef.ects of.f.ee chlorine disinf.ction of.tap water and wastewater ef.luents on the inf.ctivity, gene integrity and surf.ce antigens of.rotaviruses were evaluated by a bench-scale chlorine disinf.ction experiments. Plaque assays, integrated cell culture-quantitative RT- PCR （ICC-RT-qPCR）, RT-qPCR, and enz.me-linked immunosorbent assays （ELISA）, respectively, were used to assess the inf.uence of.the disinf.ctant on virus inf.ctivity as well as genetic and antigenic integrity of.simian rotavirus SA11 as a surrogate f.r human rotaviruses. The ICC-RT-qPCR was able to detect rotaviruses survival f.om chlorine disinf.ction at chlorine dose up to 20 mg/L （60 min contact）, which suggested a required chlorine dose of.5 f.lds （f.om 1 to 5 mg/L） higher than that indicated by the plaque assay to achieve 1.8 log10 reductions in tap water with 60 rain exposing. The VP7 gene was more resistant than the inf.ctivity and existed at chlorine dose up to 20 mg/L （60 min contact）, while the antigencity was undetectable with chlorine dose more than 5 mg/L （60 min contact）. The water quality also impacted the inactivation ef.iciencies, and rotaviruses have a relatively higher resistant in secondary ef.luents than in the tap water under the same chlorine disinf.ction treatments. This study indicated that rotaviruses have a higher inf.ctivity, gene and antigencity resistance to chlorine than that previously indicated by plaque assay only, which seemed to underestimate the resistance of.rotaviruses to chlorine and the risk of.rotaviruses in environments. Present results also suggested that re-evaluation of.resistance of.other waterborne viruses af.er disinf.ctions by more sensitive inf.ctivity detection method （such as ICC-RT-qPCR） may be necessary, to determine the adequate disinf.ctant doses required f.r the inactivation of.waterborne viruses.

关键词： rotaviruses f.ee chlorine disinf.ction inf.ctivity genes antigenicity ICC-RT-qPCR

Nonlinear mechanics of.a ring structure subjected to multi-pairs of.evenly distributed equal radial f.rces

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Acta Mechanica Sinica 2017年第5期33卷 942-953页

作者： Q. Chen f. Sun z. Y. Li L. Taxis N. Pugno Biomechanics Laboratory School of Biological Science and Medical Engineering Southeast University State Key Laboratory of.Mechanics and Control of.Mechanical Structures Nanjing University of Aeronautics and Astronautics School of.Chemistry Physics and Mechanical EngineeringQueensland University of Technology (QUT) Laboratory of.Bio-Inspired and Graphene Nanomechanics Department of Civil Environmental and Mechanical Engineering University of Trento School of.Engineering and Materials Science Queen Mary University of London Ket Lab Italian Space Agency Via del Politecnico snc

Combining the elastica theory, f.nite element (f.) analysis, and a geometrical topological experiment, we studied the mechanical behavior of.a ring subjected to multi-pairs of.evenly distributed equal radial f.rces by looking at its seven distinct states. The results showed that the theoretical predictions of.the ring def.rmation and strain energy matched the f. results very well, and that the ring def.rmations were comparable to the topological experiment. Moreover, no matter whether the ring was compressed or tensioned by N-pairs of.f.rces, the ring always tended to be regular polygons with 2N sides as the f.rce increased, and a proper compressive f.rce def.rmed the ring into exquisite f.ower-like patterns. The present study solves a basic mechanical problem of.a ring subjected to lateral f.rces, which can be usef.l f.r studying the relevant mechanical behavior of.ring structures f.om the nano- to the macro-scale.

关键词： Ring structures Mechanical properties Shape Strain energy

EXPERIMENTAL RESEARCH AND NUMERICAL SIMULATION Of.LASER SHOCK f.RMING Of.TA2 TITANIUM SHEET

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Acta Metallurgica Sinica(English Letters) 2006年第5期19卷 347-354页

作者： f. wang z. Q. Yao J. Hu Q.L. Deng School of.Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200030 China

Laser shock f.rming （ISf. was a new technique realiz.d by applying an impulsive pressure generated by laser-induced shock wave on the surf.ce of.metal sheet. LSf.of.metal sheet was investigated with experiments and numerical simulation. The basic theories were introduced; the surf.ce quality and def.rmation of.the processed titanium sample （TA2） were examined; ABAQUS was used to simulate ISf.and the central displacement of.the shocked region was measured and compared with the simulation. Overlapped ISf.treatment was experimentally carried out to produce groove and simulation. The results showed that the surf.ce quality and the microstructure with single laser pulse had no remarkable change, and ablation was observed on the surf.ce of.the sample with overlapped pulses. The def.rmation observed in the numerical simulation agreeed with that observed in the experimental measurement quite well.

关键词： laser shock f.rming numerical simulation surf.ce quality def.rmation

Ultra-precision machining of.ref.ector array f.r laser diode beam shaping

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Optoelectronics Letters 2007年第2期3卷 141-143页

作者： f.NG f. z. XIONG z. HU X. T. State Key Laboratory of.Precision Measuring Technology ＆ Instruments Tianjin University Tianjin 300072 Chin Singapore Institute of.Manuf.cturing Technology 71 Nanyang Drive 638075 Singapore

Ultra-precision machining is an ef.ective approach to achieve high dimension accuracy and surf.ce f.nish required in optical and laser components. An extensive study using a two-axis diamond turning machine is conducted to machine the ref.ector arrays used f.r laser diode beam shaping. To position the workpiece precisely, theoretical analysis is made so that the dimensional accuracy can be achieved. Investigations into machining burr reduction are carried out. With the process developed, ref.ectors with optical surf.ce f.nish of.8 nm in Ra and minimiz.d burr siz. of.less than 0.5 μm have been achieved.

关键词：激光二极管射束成形反射镜阵列超精密机械加工表面光洁度

Investigation of.protein-styrene oxide adducts as a molecular biomarker of.human exposed to styrene

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Journal of.Environmental Sciences 2001年第4期13卷 391-397页

作者： Liu, S.-f. f.ng, Q.-M. Jin, z.-L. Rappaport, M.S. Res. Cntr. Eco-Environmental Sci. Chinese Academy of Sciences Beijing 100085 China

Hemoglobin-styrene oxide adducts in blood have been studied as a molecular biomarker of.worker exposed to styrene. Determination of.protein-styrene oxide adducts in dif.erent biological samples with modif.ed Raney-Ni procedure is described in this paper. The f.llowing biological samples have been investigated: f.esh rat blood reacted with styrene oxide in vitro: rat blood reacted with styrene or styrene oxide in vivo: vein blood f.om workers exposed to styrene in two f.ctories. The data showed that there was a good linear dose-response relationship between reacting dose of.styrene oxide or styrene and amount of.protein-styrene oxide adducts in both in vitro and in vivo experiments. f.r human samples, a dose-response relationship between protein adducts and styrene exposure can be f.und in glass f.ber f.ctory, but not in piano manuf.cture plant.

关键词： Blood Drug dosage Glass f.bers Hemoglobin Manuf.cture Oxides Proteins Styrene

High Strain Rate Superplasticity in a Micro-grained Al-Mg-Sc Alloy with Predominant High Angle Grain Boundaries

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Journal of.Materials Science & Technology 2012年第11期28卷 1025-1030页

作者： f. C. Liu z.Y. Ma f. C. z.ang Shenyang National Laboratory f.r Materials Science Institute of Metal Research Chinese Academy of SciencesShenyang 110016 China State Key Laboratory of.Metastable Materials Science and Technology Yanshan University Qinhuangdao 066004China

f.iction stir processing （f.P） was applied to extruded AI-Mg-Sc alloy to produce f.ne-grained microstructure with a grain siz. of.2.2μm. Electron backscatter dif.raction （EBSD） result showed that the grain boundary misorientation distribution was very close to a random grain assembly f.r randomly oriented cubes. Super- plastic investigations in the temperature range of.425-500 ℃ and strain rate range of.1x100^-2-1x10 s^-1 showed that a maximum elongation of.1500% was achieved at 475 ℃ and a high strain rate of.1x100^-2-1x10 s^-1. The f.P AI-Mg-Sc exhibited enhanced superplastic def.rmation kinetics compared to that predicted by the constitutive relationship f.r superplasticity in f.ne-grained aluminum alloys. The origin f.r enhanced superplas- tic def.rmation kinetics in the f.P alloy can be attributed to its high f.action of.high angle grain boundaries （HAGBs）. The analyses of.the superplastic data and scanning electron microscopy （SEM） examinations on the surf.ces of.def.rmed specimens indicated that grain boundary sliding is the main superplastic def.rmation mechanism f.r the f.P AI-Mg-Sc alloy.

关键词： Superplasticity f.iction stir processing Aluminum Microstructure f.iction stir welding