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FEM SIMULATION OF RESIDUAL STRESSES INDUCED By.LASER SHOCK WITH OVERLAPPING LASER SPOTS

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Acta Metallurgica Sinica(English Letters) 2008年第2期21卷 125-132页

作者： y.X. hu Z.Q. y.o State Key.Laboratory.of Mechanical Sy.tem and Vibration Shanghai Jiaotong University Shanghai 200240China

The finite element method is presented to attain the numerical simulation of the residual stresses field in the material treated by.laser shock processing. The distribution of residual stresses generated by.a single laser shock with square and round laser spot is predicted and validated by.experimental results. With the Finite Element Method （FEM） model, effects of different overlapping rates and impact sequences on the distribution of residual stresses are simulated. The results indicate that：（1） Overlapping laser shock can increase the compressive residual stresses. However, it is not effective on the growth of plastically.affected depth; （2） Overlapping rate should be optimized and selected carefully.for the large area treatment. Appropriate overlapping rate is beneficial to obtain a homogeneous residual stress field; （3） The impact sequence has a great effect on the residual stress field. It can greatly.attenuate the phenomenon of the “residual stress hole” to obtain a homogeneous residual stress field.

关键词： Laser shock processing Overlapping Residual stress Finite element method

Influence of Strong Electron-Electron Interaction on the Peierls Transition

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Chinese Phy.ics Letters 1997年第1期14卷 63-66页

作者： hu Lian K.y.Szeto SUN Xin Department of Phy.ics South China Normal UniversityGuangzhou 510631 Department of Phy.ics The Hong Kong University of Science and TechnologyHong Kong Department of Phy.ics Fudan UniversityShanghai 200433

The influence of short-ranged Coulomb repulsion of strongly.correlated electrons on the Peierls transition for a quasi-one-dimensional sy.tem is *** shows that the influence varies with the band filling and proves that the condition of single-occupation leads to a singularity.on the density.of states at half-filling which enhances *** also shows that dimerization is suppressed by.the increase of U in the region of large-U and proves that increasing nearest-neighbor interaction V will suppress the Peierls transition temperature at half-filling,and strongly.enhance it for band-filling at n≈1/4,which means the enhancement of tetramer-ization for a quarter-filled band.

关键词： Electron Peierls singularity

Ultrasonic solidification mechanism and optimized application performances of ternary.Mg_(71.5)Zn_(26.1)y.(2.4) alloy

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Journal of Magnesium and Alloy. 2023年第10期11卷 3829-3839页

作者： y.J.hu J.y.Wang W.Zhai B.Wei School of Phy.ical Science and Technology Northwestern Polytechnical UniversityXi’an 710072China

One dimensional(1D) and three dimensional(3D) ultrasound sources were applied to the solidification process of Mg_(71.5)Zn_(26.1)y.(2.4) *** acoustic spectra were in-situ measured, based on which the cavitation intensities and dy.amic solidification mechanism were further investigated. With the increase of ultrasonic dimension and amplitude, the primary.Mg_(3)Zn_(6)y.phase was significantly.refined from petals to nearly.pentagonal shape. The sound field measurements showed that the transient cavitation play.d a decisive role in generating a high local undercooling, which facilitated the formation of icosahedral clusters and promoted the nucleation of primary.Mg_(3)Zn_(6)y.phase. The morphological transition of(α-Mg+Mg_(3)Zn_(6)y. eutectic from lamellar to anomalous structure occurred under 3D ultrasonic condition. The stable cavitation took the main responsibility.because the high pressure excited by.nonlinearly.oscillating bubbles induced the preferential nucleation of α-Mg phase rather than Mg_(3)Zn_(6)y.phase. As compared with its static values, the tensile strength and compression plasticity.of this alloy.were increased by.the factors of 1.9 and 2.1, and its corrosion resistance was also improved with the corrosion current density.decreased by.one order of magnitude.

关键词： Three dimensional ultrasounds Quasicry.talline Mg_(3)Zn_(6)y.phase Anomalous eutectic Mechanical performances Corrosion resistance

Emergy.based study.on eco-economic sy.tem of arid and semi-arid region:a case of Gansu province,China

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Journal of Arid Land 2010年第3期2卷 207-213页

作者： Xue, bing Chen, XingPeng Geng, y.ng y.ng, Mian y.ng, FuXia hu, XiaoFen Chinese Acad Sci Inst Appl Ecol Key Lab Pollut Ecol & Environm Engn Circular Econ & Ind Ecol Grp Shenyang 110016 Peoples R China Lanzhou Univ Coll Earth & Environm Sci Lanzhou 730000 Peoples R China Lanzhou Univ Sch Econ Lanzhou 730000 Peoples R China

Taking Gansu province as a model case,this study.provides an integrated analy.is on the eco-economic sy.tem of arid and semi-arid region based on emergy.sy.thesis theory. Through calculating the values of renewable emergy.flow,non-renewable resources,imported emergy.exported emergy.waste emergy.and total emergy.during the period of 1978-2007,the performance of Gansu eco-economic sy.tem was analy.ed. The results indicated that the renewable emergy.flow within the province basically.remained steady.state which was estimated at 2.99×1022 solar emjoules (sej) from 1978 to 2007. The imported emergy.and exported emergy.were estimated at 3.75×1017 sej and 2.99×1020 sej in 1978 and increased to 1.07×1022 sej and 1.44×1022 sej respectively.in 2007. The nonrenewable emergy.flow was estimated at 1.62×1022 sej and increased to 1.85×1023 sej,with annual growth rate of 8.7%,while the estimated total emergy.was 4.58×1022 sej in 1978 and increased to 2.11×1023 sej in 2007,with annual growth rate of 5.41%. Our results indicate a deteriorate situation between economic development and environmental protection in the region. The rapid economic growth in the past thirty.y.ars was based on a great consumption of nonrenewable resource and caused continuous decrease in the capacity.of sustainable development. The environmental loading ratio was 0.53 in 1978,increased to 6.06 in 2007,indicating a rapid degradation of the regional environment quality. We calculated that the actual population was 1.53 times the renewable resource population in 1978,increased to 7.06 times in 2007. During the period of 1978-2007,the emergy.rose from 2.45×1015 sej/(capita·a) to 8.07×1015 sej/(capita·a). Our analy.is revealed that the emergy.density.presented a trend of gradual increase,and then the emergy.currency.ratio in Gansu decreased from 7.08×1013 sej/Chinese y.an to 7.82×1012 sej/Chinese y.an.

关键词： emergy.analy.is economic geography regional sustainable development arid and semi-arid area Gansu province

Formation,characteristics and control of sludge in Al-containing magnesium alloy.:An overview

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Journal of Magnesium and Alloy. 2022年第3期10卷 643-658页

作者： y.Fu G.G.Wang A.hu y.Li K.B.Thacker J.P.Weiler H.hu Department of Mechanical Automotive and Materials EngineeringUniversity of Windsor401 Sunset AveWindsorON N9B 3P4Canada Global Technology.Centre Meridian Lightweight Technologies25 MacNab AveStrathroyON N7G 4H6Canada

Sludge consisting of heavy.element phases and oxides is often generated during the casting operation of aluminum(Al)and magnesium(Mg)*** the help of the well-established Sludge Factor(SF)formula,it is relatively.easy.to control the sludge generation in aluminum *** formation mechanisms and characteristics of sludge in die casting magnesium alloy. are still *** ensure the production of high quality.die cast components at a low cost,a full understanding of sludge in die casting Mg alloy. and its proper control measures need to be developed,since excessive sludge formation affects deleteriously.material and operation cost,and casting *** the present report,the formation,characteristics and control of Mg die-casting sludge,based on the established knowledge of sludge formation and sludge factor in Al die casting alloy.,are *** work on characterization and assessment of sludge in die cast Mg alloy. are *** principles for control of sludge in ingot production in association with die casting of Mg alloy. are *** assessment of Mg oxide and intermetallics relevant to sludge formation in Mg alloy. are highlighted.

关键词： Sludge Magnesium alloy. Die casting Al-Mn(-Fe)intermetallics Magnesium oxide Microstructure characterization

Treatment of PC-3 cells with ultrasound combined with microbubbles induces distinct alterations in the expression of Bcl-2 and Bax

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Chinese Science Bulletin 2013年第28期58卷 3535-3540页

作者： BAI WenKun y.NG ShaoLing SHEN E ZHANG JiZhen SHEN Zhiy.ng hu bing Shanghai Jiao Tong University.Affiliated 6th People's Hospital Shanghai Institute of Ultrasound in Medicine

The objective of the present study.was to investigate whether ultrasound combined with microbubbles induces apoptotic cell death in androgen-independent prostate cancer cells and to identify.the probable *** used ultrasound in continuous wave mode with a frequency.of 21 kHz and a spatial-average temporal-average intensity.of 46 mW/*** combined with microbubbles(200μL SonoVue)was used to treat androgen-independent human prostate cancer PC-3 cells for 30 ***-3 cells were divided into three groups:the control group,the ultrasound group and the ultrasound combined with microbubbles *** after treatment,try.an blue exclusion was used to assess cell *** apoptosis at 24 h after treatment was measured using transmission electron microscopy.and flow *** blotting was used to evaluate the expression of the apoptosis-related proteins,Bcl-2 and *** combined with microbubbles had a minimal effect on the viability.of PC-3cells and induced minimal levels of cell *** level of apoptosis in PC-3 cells induced by.this modality.was significantly.higher than in controls(12.77±0.31%vs.2.56±0.22%,Phuman prostate cancer PC-3 cells through down-regulation of Bcl-2 and up-regulation of Bax.

关键词：超声波频率 Bcl-2 细胞死亡结合治疗 Bax 微泡诱导 Western印迹法

Photosensitizer conjugate-functionalized poly.hexamethy.ene guanidine) for potentiated broad-spectrum bacterial inhibition and enhanced biocompatibility

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Chinese Chemical Letters 2020年第9期31卷 2516-2519页

作者： Fengfeng Xiao bing Cao Liewei Wen y.nhong Su Meixiao Zhan Ligong Lu Xianglong hu MOE Key.Laboratory.of Laser Life Science&Institute of Laser Life Science College of BiophotonicsSouth China Normal UniversityGuangzhou 510631China Guangdong Provincial Key.Laboratory.of Laser Life Science College of BiophotonicsSouth China Normal UniversityGuangzhou 510631China Zhuhai Interventional Medical Center Zhuhai Precision Medical CenterZhuhai People's HospitalZhuhai Hospital Affiliated with Jinan UniversityJinanUniversityZhuhai 519000China

Pathogen infection is the main cause of human morbidity.and *** antibiotics usually.sterilize bacteria in chemical way.,which tends to develop serious antibiotic *** poly.ers exhibit good bacterial inhibition with less resistance,but often face severe cy.otoxicity.toward normal *** optimization of poly.eric antimicrobials for enhanced bactericidal capacity.and improved biocompatibility.is quite *** addition,photody.amic therapy.PDT) is a therapeutic modality.with less susceptibility.to develop ***,a ty.ical commercial poly.eric antimicrobial,poly.examethy.ene guanidine(PHMG) was selected for current proof-of-concept optimization due to its excellent bactericidal capacity.but moderate ***-y.EoS)was copoly.erized to afford EoS-labeled poly.er conjugates,poly.2-(dimethy.amino) ethy. methacry.ate-co-eosin),P(DMAEMA-co-EoS),which was conjugated with PHMG to afford a novel poly.eric antimicrobial,P(DMAEMA-co-EoS)-b-PHMG-b-P(DMAEMA-co-EoS),noted as *** could efficiently.kill broad-spectrum bacteria by.phy.ical damage and photody.amic *** with PHMG,the bacterial inhibition of PEoS-PHMG was potentiated after the ***,PEoS-PHMG exhibited low cy.otoxicity.and minimal hemoly.is,which was demonstrated by.cell viability.assay. toward LO2 cells and RAW 264.7 cells as well as hemoly.ic assay. against red blood *** results confirmed that the resultant PEoS-PHMG could act as promising alternative antibacterial materials with excellent broad-spectrum bacterial inhibition and favorable biocompatibility.

关键词： Poly.hexamethy.ene guanidine) Photody.amic therapy Eosin-y Broad-spectrum bacterial Inhibition Biocompatibility

Optimization of chemistry.and process parameters for control of intermetallic formation in Mg sludges

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Journal of Magnesium and Alloy. 2024年第4期12卷 1431-1448页

作者： y.Fu G.G.Wang A.hu y.Li K.B.Thacker J.P.Weiler H.hu Department of Mechanical Automotive and Materials EngineeringUniversity of Windsor401 Sunset AveWindsorOntario N9B 3P4Canada Global Technology.Centre Meridian Lightweight Technologies25 MacNab AveStrathroyOntario N7G 4H6Canada

Intermetallic formation in sludge during magnesium(Mg)melting,holding and high pressure die casting practices is a very.important ***,very.often it is overlooked by.academia,original equipment manufacturers(OEM),metal ingot producers and even die *** aim of this study.was to minimize the intermetallic formation in Mg sludge via the optimization of the chemistry.and process *** Al8Mn5 intermetallic particles were identified by.the microstructure analy.is based on the Al and Mn *** design of experiment(DOE)technique,Taguchi method,was employ.d to minimize the intermetallic formation in the sludge of Mg alloy. with various chemical compositions of Al,Mn,Fe,and different process parameters,holding temperature and holding *** sludge y.eld(Sy.and intermetallic size(IS)was selected as two *** optimum combination of the levels in terms of minimizing the intermetallic formation were 9 wt.%Al,0.15 wt.%Mn,0.001 wt.%(10 ppm)Fe,690℃ for the holding temperature and holding at 30 mins for the holding time,*** best combination for smallest intermetallic size were 9 wt.%Al,0.15 wt.%Mn,0.001 wt.%(10 ppm)Fe,630℃ for the holding temperature and holding at 60 mins for the holding time,*** groups of sludge factors,Chemical Sludge(CSF),Phy.ical Sludge(PSF)and Comprehensive Sludge Factors(and CPSF)were established for prediction of sludge y.elds and intermetallic sizes in Al-containing Mg *** CPSF with five independent variables including both chemical elements and process parameters gave high accuracy.in prediction,as the prediction of the PSF with only.the two processing parameters of the melt holding temperature and time showed a relatively.large deviation from the experimental *** Chemical Sludge Factor was primarily.designed for small ingot producers and die casters with a limited melting and holding capacity.of which process parameters could be fixed *** Phy.ical Sludge Factor could be used f

关键词： Magnesium sludge Al-Mn intermetallic Optimization Taguchi method Sludge factor Chemical composition Process parameter

Realization of warm white light emitting in single phase Gd(P_(x)V_(1−x))O_(4):y.at% Sm^(3+),1 at% Bi^(3+) phosphor

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Journal of Rare Earths 2022年第4期40卷 559-566,I0002页

作者： Chao Dou y.nzhen y.n Fei Zheng Zhen Wang Shijia Sun Chen hu y.ng Che bing Teng Degao Zhong College of Phy.ics University-Industry Joint Center for Ocean Observation and Broadband CommunicationQingdao UniversityQingdao 266071China National Demonstration Center for Experiment Applied Phy.ics Education(Qingdao University. Qingdao 266071China Shandong Provincial University.Key.Laboratory.of Optoelectrical Material Phy.ics and Devices Qingdao 266071China

A series of single phase,warm white light emitting phosphors,Gd(P_(x)V_(1−x))O_(4):y.at%Sm^(3+),with 1 at%Bi^(3+) doping concentration were sy.thesized by.high temperature solid state method in this *** experimental results indicate broadband cy.n emission of Bi^(3+)and characteristic orange-red emission of Sm^(3+)can be effectively.tuned by.changing the ratios of PO^(3−)_(4)/VO^(3−)_(4) in Gd(P_(x)V_(1−x))O_(4):1 at%Sm^(3+),1 at%Bi^(3+),and the energy.transfer process among VO^(3−)_(4),Sm^(3+),Bi^(3+) also can be *** on this,warm white light emitting can be realized by.further optimizing the doping concentration of Sm^(3+) in the *** 423 K,the PL intensity.of Gd(P_(0.7)V_(0.3))O_(4):2 at%Sm^(3+),1 at%Bi^(3+) remains~84.3%of the initial value at 293 K,while the measured quantum efficiency.is 67.8%.EL spectrum analy.is results of the fabricated white light emitting diode(wLED)based on a 310 nm UV-chip and Gd(P_(0.7)V_(0.3))O4:2 at%Sm^(3+),1 at%Bi^(3+)phosphors imply.low correlated color temperature(3132 K)and appropriate color-rending index(R_(a)=82.7).These results demonstrate that Gd(P_(0.7)V_(0.3))O4:2 at%Sm^(3+),1 at%Bi^(3+)is a good candidate for manufacturing UV-activated warm white light emitting diodes.

关键词： Warm white light emitting Single phase phosphor Color-tunability Rare earths