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Cluster size and substrate temperature affecting thin film formation during copper cluster deposition on a Si(001) surface

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Chinese Physics B 2012年第11期21卷 190-197页

作者：龚恒风吕炜王鲁闽李公平 School of nuclear science and technology Lanzhou University department of Mechanical Engineering University of Michigan department of nuclear Engineering and Radiological science University of Michigan

the soft deposition of Cu clusters on a Si （001） surface was studied by molecular dynamics simulations. the embedded atom method, the Stillinger-Weber and the Lennar-Jones potentials were used to describe the interactions between the cluster atoms, between the substrate atoms, and between the cluster and the substrate atoms, respectively. the Cu13, Cu55, and Cu147 clusters were investigated at different substrate temperatures. We found that the substrate temperature had a significant effect on the Cn147 cluster. For smaller Cu13 and Cu55 clusters, the substrate temperature in the range of study appeared to have little effect on the mean center-of-mass height. the clusters showed better degrees of epitaxy at 800 K. With the same substrate temperature, the Cu55 cluster demonstrated the highest degree of epitaxy, followed by Cu147 and then Cu13 clusters. In addition, the Cu55 cluster showed the lowest mean center-of-mass height. these results suggested that the Cu55 cluster is a better choice for the thin-film formation among the clusters considered. Our studies may provide insight into the formation of desired Cu thin films on a Si substrate.

关键词： copper cluster deposition epitaxy diffusion

Calculation and analysis of cross-sections for p+^(184)W reactions up to 200 MeV

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Chinese Physics C 2015年第8期39卷 43-49页

作者：孙建平张正军韩银录 department of Physics Northwest University science and technology on nuclear Data laboratory China Institute of Atomic Energy

A set of optimal proton optical potential parameters for pd-lS4w reactions are obtained at incident proton energy up to 250 MeV. Based on these parameters, the reaction cross-sections, elastic scattering angular distributions, energy spectra and double differential cross sections of proton-induced reactions on lS4w are calculated and analyzed by using theoretical models which integrate the optical model, distorted Born wave approximation theory, intra- nuclear cascade model, exciton model, Hauser-Feshbach theory and evaporation model. the calculated results are compared with existing experimental data and good agreement is achieved.

关键词： reaction models elastic scattering angular distribution energy spectra double differential cross-section

CFD simulation of thermal hydraulic characteristics in a typical upper plenum of RPV

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Frontiers in Energy 2021年第4期15卷 930-945页

作者： Mingjun WANG Lianfa WANG Yingjie WANG Wenxi tIAN Jian DENG Guanghui SU Suizheng QI State Key laboratory of Multiphase Flow in Power Engineering Department of Nuclear Science and TechnologyXi’an Jiaotong UniversityXi’an 710049China science and technology on Reactor System Design technology laboratory Nuclear Power Institute of ChinaChengdu 610213China

A comparative computational fluid dynamics(CFD)study was conducted on the three different types of pressurized water reactor(PWR)upper plenum,named tYPE 1(support columns(SCs)and control rod guide tubes(CRGts)with two large windows),tYPE 2(SCs and CRGts without windows),and tYPE 3(two parallel perforated barrel shells and CRGts).First,three types of upper plenum geometry information were collected,simplified,and adopted into the BORA facility,which is a 1/5 scale system of the four-loop PWR ***,the geometry,including the upper half core,upper plenum region,and hot legs,was built using the Salome *** that,an unsteady calculation to simulate the reactor balance operation at hot full power scenario was ***,the differences of flowrate distribution at the core outlet and temperature distribution and transverse velocity inside the hot legs with different upper plenum internals were *** results suggest that tYPE 1 upper plenum internals cause the largest flowrate difference at the core outlet while tYPE 3 leads to the most even distributed *** distribution and evolution pattern of the tangential velocity inside hot legs is highly dependent on the upper plenum *** counter-rotating swirls exist inside the tYPE 1 hot leg and only one swirl revolving around the hog leg axis exist inside the tYPE 2 hot *** tYPE 3,two swirls like that of tYPE 1 rotating around the hot leg axis significantly increase the temperature homogenization *** research provides meaningful guidelines for the future optimization and design of advanced PWR upper plenum internal structures.

关键词： pressurized water reactor(PWR) upper plenum internal structures temperature distribution computational fluid dynamics(CFD)

Localized Vibrational Modes of Excitation in Electroluminescent Polymers

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Chinese Physics Letters 1999年第11期16卷 836-837页

作者： JIANG Hao XU Xiao-hua SUN Xin KYonemitsu t.D.lee laboratory and department of Physics Fudan UniversityShanghai 200433 National laboratory of Infrared Physics Shanghai Institute for Technical PhysicsShanghai 200083 Institute for Molecular science Okazaki 444-8585Japan

the localized vibrational modes of exciton and polaron are investigated, and the results show that the frequencies of the three even parity modes of exciton are very different from those of polaron. For the exciton, three modes are distinctly separated;but, for the polaron, two modes with higher frequencies are close to each other, then, it is possible to distinguish exciton from polaron by watching their Roman spectra. therefore, the localized mode may be used to specify the exciton and polaron in the electroluminesent polymers.

关键词： spectra. polaron vibrational

A novel flexible nerve guidance conduit promotes nerve regeneration while providing excellent mechanical properties

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Neural Regeneration Research 2025年第7期20卷 2084-2094页

作者： tong Li Quhan Cheng Jingai Zhang Boxin Liu Yu Shi Haoxue Wang Lijie Huang Su Zhang Ruixin Zhang Song Wang Guangxu Lu Peifu tang Zhongyang Liu Kai Wang department of Orthopedics the Fourth Medical Center of Chinese PLA General HospitalBeijingChina department of training and Sports Medicine Characteristic Medical Center of Chinese People’s Armed Police ForceTianjinChina Medical School of Chinese PLA BeijingChina Key laboratory of Bioactive Materials for the Ministry of Education College of Life SciencesNankai UniversityTianjinChina department of Orthopedics Tianjin HospitalTianjinChina department of Rehabilitation Medicine Er Quan Hospital of PAPWuxiJiangsu ProvinceChina

Autografting is the gold standard for surgical repair of nerve defects>5 mm in length;however,autografting is associated with potential complications at the nerve donor *** an alternative,nerve guidance conduits may be *** ideal conduit should be flexible,resistant to kinks and lumen collapse,and provide physical cues to guide nerve *** designed a novel flexible conduit using electrospinning technology to create fibers on the innermost surface of the nerve guidance conduit and employed melt spinning to align ***,we prepared disordered electrospun fibers outside the aligned fibers and helical melt-spun fibers on the outer wall of the electrospun fiber *** presence of aligned fibers on the inner surface can promote the extension of nerve cells along the *** helical melt-spun fibers on the outer surface can enhance resistance to kinking and compression and provide *** novel conduit promoted nerve regeneration and functional recovery in a rat sciatic nerve defect model,suggesting that it has potential for clinical use in human nerve injuries.

关键词： aligned fibers anti-kinking helical fibers nerve guidance conduit nerve regeneration peripheral nerve injury topological guidance

Polydispersity effects on the magnetization of diluted ferrofluids:a lognormal analysis

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Chinese Physics B 2010年第10期19卷 534-540页

作者：王旭飞施立群 Applied Ion Beam Physics laboratory Fudan University Key Laboratory of the Ministry of Education Institute of Modern Physics Department of Nuclear Science and Technology Fudan University

Based on a lognormal particle size distribution, this paper makes a model analysis on the polydispersity effects on the magnetization behaviour of diluted ferrofluids. Using a modified Langevin relationship for the lognormal dispersion, it first performs reduced calculations without material parameters. From the results, it is extrapolated that for the ferrofluid of lognormal polydispersion, in comparison with the corresponding monodispersion, the saturation magnetization is enhanced higher by the particle size distribution. It also indicates that in an equivalent magnetic field, the lognormally polydispersed ferrofluid is magnetically saturated faster than the corresponding monodispersion. Along the theoretical extrapolations, the polydispersity effects are evaluated for a typical ferrofluid of magnetite, with a dispersity of σ = 0.20. the results indicate that the lognormal polydispersity leads to a slight increase of the saturation magnetization, but a noticeable increase of the speed to reach the saturation value in an equivalent magnetic field.

关键词： ferrofluid polydispersity effects lognormal distribution

Effect of Cu on the boron segregation at grain boundaries and vacancy-type defects in ultra-low carbon micro-alloy steels

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science China(technological sciences) 2014年第6期57卷 1135-1141页

作者： YANG RuiJie WU Ping LI XiangLong ZHANG ShiPing CHEN Sen WANG BaoYi JU Xin department of Physics School of Mathematics and PhysicsUniversity of Science and Technology Beijing Key laboratory of nuclear Analysis techniques

By thermal neutron irradiation particle tracking autoradiography(PtA)technique,the development of boron segregation at grain boundaries in ultra-low carbon micro-alloy steels was investigated during cooling from 1150°C to 850°C,and the effect of Cu on boron segregation at grain boundaries was *** positron annihilation lifetime(PAL)technique,the changes of vacancy-type defects with temperatures and the effect of Cu on vacancy-type defects in the cooling process were *** show that,the concentration of boron at grain boundaries increases rapidly at the beginning of the cooling;after that,it begins to decrease;and then,it increases gradually *** addition of Cu not only increases the concentration of boron at grain boundaries but also speeds up the development process of boron segregation at grain *** the continuous cooling process,the addition of Cu significantly affects the change of vacancy-type defects with temperatures in ultra-low carbon micro-alloy steels.

关键词： particle tracking autoradiography(PtA) technique boron segregation at grain boundaries positron annihilation lifetime(PAL) technique vacancy-type defects ultra-low carbon micro-alloy steels

the Impact of Beam Deposition on Bootstrap Current of Fast Ion Produced by Neutral Beam tangential Injection

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Chinese Physics Letters 2015年第8期32卷 107-110页

作者：黄千红龚学余路兴强余俊曹锦佳 department of nuclear science and technology University of South China

the density profile of fast ions arising from a tangentially injected diffuse neutral beam in tokamak plasma is calculated. the effects of mean free paths and beam tangency radius on the density profile are discussed under typical HL-2A plasmas parameters. the results show that the profile of fast ions is strongly peaked at the center of the plasma when the mean free path at the maximum deuteron density is larger than the minor radius, while the peak value decreases when the mean free path at the maximum deuteron density is larger than twice that of the minor radius due to the beam transmission loss. Moreover~ the bootstrap current of fast ions for various mean free paths at the maximum deuteron density is calculated and its density is proved to be closely related to the deposition of the neutral beam. With the electron return current considered, the net current density obviously decreases. Meanwhile, the peak central fast ion density increases when the beam tangency radius approaches the major radius, and the net bootstrap current increases rapidly with the increasing beam tangency radius.

关键词： DEUtERONS tOKAMAKS BOOtStRAP circuits PLASMA beam injection heating ELECtRIC lines

Impulse force reductions and their effects on WBV exposures in high impact shovel loading operations

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International Journal of Mining science and technology 2018年第3期28卷 423-435页

作者： Danish Ali Samuel Frimpong Mining & nuclear Engineering department Missouri University of Science and Technology

When shovels load the dump trucks with over 100-ton passes under gravity dumping conditions, they will create a large impact force on the dump truck body which generates high frequency shock waves which expose the operators to whole body vibrations （WBV）. the main cause of such truck vibrations is the large impact force due to the gravity dumping of large tonnage passes. therefore a rigorous mathematical model has been developed for the impact force containing all the necessary factors upon which it depends. Latter, a thorough analysis shows that percentage reduction of 7.19%, 9.40%, 13.27%, 14.8%, 17.30% and 18.13% can he achieved by reducing the dumping distance to 6.33 m, 6.0 m, 5.5 m, 5.33 m, 5.0 m and 4.9 m, respectively, as compared to when the dumping distance was 7.33 m. Even more reduction in the magnitude of impact force can he observed if the shovel pass gets divided into more than two sub-passes. therefore, these models can he used to figure out the number of sub-passes into which a single ore pass can he divided and/or the extent to which the dumping distance can he reduced which would reduce the impact force significantly enough to obtain safer yet economic operations.

关键词： Impact force HISLO Mathematical modeling Dumping distance Shovel ore sub-passes