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ATOMIC STATES AND BRITTLENESS OF hcp Ti_3Al-ORDERED-TyPE ALLOyS

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Acta Metallurgica Sinica(English Letters) 2007年第4期20卷 270-276页

作者： H.J. peng y.Q. xie College of Chemistry and Chemical Engineering Central South University Changsha 410083 China College of Materials Science and Engineering Central South University Changsha 410083 China

On the basis of the framework of systematic science of alloys （SSA）, the basic information such as states, volumes, and potential energies of characteristic atoms in hcp Ti-Al system have been determined. The average atomic state of the hcp Ti3Al compound consisting of ψ4^Ti and ψ0^Al atoms is 0.75[Ar] （3dn）^0.573 （3dc）^2.1685 （4sc）^0.972 （4sf）^0.3093 ＋ 0.25[Ne] （3sc）^1.32 （3pc）^1.19 （3sf ＋ 3pf）^0.49. The brittleness of the ordered hcp Ti3Al compound has been discussed considering the fundamental factors, which are atomic states, bond networks, potential energy wave planes, and the ratio xTi/xAl. The existence of more pc and more dc directional electrons in the hcp Ti3Al compound lead to considerable brittleness; From bond networks and potential energy wave planes, the hcp Ti3Al compound has poorer ductility than the pure hcp Ti metal and the pure fcc Al metal; The Al-rich hcp Ti3Al ordered type alloys have poorer ductility than the Ti-rich hcp Ti3Al ordered type alloys.

关键词： Ti3Al alloy atomic state brittleness

The Role of TNF Related Apoptosis-Inducing Ligand in Neurodegenerative Diseases

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Cellular & Molecular Immunology 2005年第2期2卷 113-122页

作者： y.Huang N.Erdmann H.peng y.Zhao ThelaboratoryofNeurotoxicologyattheCenterforNeurovirology＆NeurodegenerativeDisorders ／／Dept.Pharmacology Dept.ofSurgery UniversityofNebraskaMedicalCenterOmahaNE68198-5880USA／／InstituteofAnimalResearchChineseAcademyofScienceChina

A hallmark of all forms of neurodegenerative diseases is impairment of neuronal functions,and in many cases neuronal cell *** the etiology of neurodegenerative diseases may be distinct,different diseases display a similar pathogenesis,for example abnormal immunity within the central nervous system(CNS),activation of macrophage/microglia and the involvement of proinflammatory *** studies show that neurons in a neurodegenerative state undergo a highly regulated programmed cell death,also called ***-related apoptosis-inducing ligand(TRAIL),a member of the TNF family,has been shown to be involved in apoptosis during many *** one member of a death ligand family,TRAIL was originally thought to target only tumor cells and was not present in ***,recent data showed that TRAIL was unregulated in HIV-1-infected and immune-activated macrophages,a major disease inducing cell during HIV-1-assoeiated dementia(HAD).TRAIL is also induced on neuron by β-amyloid protein,an important pathogen for Alzheimer's *** this review,we summarize the possible common aspects that TRAIL involved those neurodegenerative diseases,TRAIL induced apoptosis signaling in the CNS cells,and specific role of TRAIL in individual *** & Molecular Immunology.2005;2(2):113-122.

关键词： Alzheimer's disease HⅣ-1 associated dementia multiple sclerosis apoptosis TRAIL macrophage

SIx SINAPyL ALCOHOL DERIVATIVES FROM LIGULARIA NELUMBIFOLIA

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Chinese Chemical Letters 1995年第5期6卷 387-390页

作者： Zhao, y peng, HR Jia, ZJ Lanzhou Univ Inst Organ Chem Natl Lab Appl Organ Chem Lanzhou 730000 Peoples R China

Further phytochemical investigation of the roots of Ligularia nelumbi folia afforded six new sinapyl alcohol derivatives. Their structures were elucidated by high field NMR spectroscopy.

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Five-fold local symmetry in metallic liquids and glasses

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Chinese Physics B 2017年第1期26卷 10-19页

作者： M Z Li H L peng y C Hu F x Li H P Zhang W H Wang Department of Physics Beijing Key Laboratory of Opto-electronic Functional Materials ＆ Micro-nano Devices Renmin University of China Beijing 100872 China Institute of Physics Chinese Academy of Sciences Beijing 100091 China

The structure of metallic glasses has been a long-standing mystery. Owing to the disordered nature of atomic structures in metallic glasses, it is a great challenge to find a simple structural description, such as periodicity for crystals, for establishing the structure–property relationship in amorphous materials. In this paper, we briefly review the recent developments of the five-fold local symmetry in metallic liquids and glasses and the understanding of the structure–property relationship based on this parameter. Experimental evidence demonstrates that five-fold local symmetry is found to be general in metallic liquids and glasses. Comprehensive molecular dynamics simulations show that the temperature evolution of five-fold local symmetry reflects the structural evolution in glass transition in cooling process, and the structure–property relationship such as relaxation dynamics, dynamic crossover phenomena, glass transition, and mechanical deformation in metallic liquids and glasses can be well understood base on the simple and general structure parameter of five-fold local symmetry.

关键词： metallic glass structure–property relation five-fold local symmetry

Three-Dimensional Lattice Kinetic Scheme and its Application to Simulate Incompressible Viscous Thermal Flows

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Communications in Computational Physics 2007年第2期2卷 239-254页

作者： y.peng C.Shu y.T.Chew Department of Mechanical Engineering National University of Singapore10 Kent Ridge CrescentSingapore 119260.

In this paper,the three-dimensional lattice kinetic scheme is presented to simulate incompressible viscous thermal *** compared with the standard LBM,the present scheme has the following good *** can save the computer memory since there is no need to store the density *** the conventional NS solvers,the implementation of boundary conditions is straightforward since the dependent variables are the macroscopic flow *** easy implementation of boundary conditions is a good property for solving three-dimensional flow *** present scheme is validated by simulating the three-dimensional natural convection in an air-filled cubical enclosure,which is heated differentially at two vertical side *** obtained numerical results compare very well with available data in the literature.

关键词： Lattice kinetic scheme lattice Boltzmann method three-dimensional incompressible flow natural convection thermal flow.

Nanoscale Wire Bonding of Individual Ag Nanowires on Au Substrate at Room Temperature

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Nano-Micro Letters 2017年第3期9卷 27-32页

作者： peng peng Wei Guo ying Zhu Lei Liu Guisheng Zou y.Norman Zhou School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191People’s Republic of China International Research Institute for Multidisciplinary Science Beihang UniversityBeijing 100191People’s Republic of China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084People’s Republic of China Centre for Advanced Materials Joining University of WaterlooWaterlooON N2L 3G1Canada

The controllable wire bonding of individual Ag nanowires onto a Au electrode was achieved at room temperature. The plastic deformation induced by pressure using nanoindentation could break the protective organic shell on the surface of the Ag nanowires and cause atomic contact to promote the diffusion and nanojoining at the Ag and Au interface. Severe slip bands were observed in the Ag nanowires after the deformation. A metallic bond was formed at the interface, with the Ag diffusing into the Au more than the Au diffused into the Ag. This nanoscale wire bonding might present opportunities for nanoscale packaging and nanodevice design.

关键词： Nanojoining Bonding Diffusion Interface Nanoindentation

A neuron-immune circuit regulates neurodegeneration in the hindbrain and spinal cord of Arf1-ablated mice

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National Science Review 2023年第12期10卷 98-110页

作者： Guohao Wang Shuhan Jin Jiaqi Liu xu Li peng Dai yuetong Wang Steven x.Hou The Basic Research Laboratory Center for Cancer ResearchNational Cancer Institute at FrederickNational Institutes of Health Department of Cell and Developmental Biology at the School of Life Sciences State Key Laboratory of Genetic EngineeringInstitute of Metabolism and Integrative BiologyHuman Phenome Institute Department of Liver Surgery and Transplantation of Liver Cancer Institute at Zhongshan Hospital Fudan University

Neuroimmune connections have been revealed to play a central role in neurodegenerative diseases(NDs).However, the mechanisms that link the central nervous system(CNS) and peripheral immune cells are still mostly unknown. We recently found that specific ablation of the Arf1 gene in hindbrain and spinal cord neurons promoted NDs through activating the NLRP3 inflammasome in microglia via peroxided lipids and adenosine triphosphate(ATP) releasing. Here, we demonstrate that IL-1β with elevated chemokines in the neuronal Arf1-ablated mouse hindbrain and spinal cord recruited and activated γ δ T cells in meninges. The activated γ δ T cells then secreted IFN-γ that entered into parenchyma to activate the microglia-A1astrocyte-C3-neuronal C3a R neurotoxic pathway. Remarkably, the neurodegenerative phenotypes of the neuronal Arf1-ablated mice were strongly ameliorated by IFN-γ or C3 knockout. Finally, we show that the Arf1-reduction-induced neuroimmune-IFN-γ-gliosis pathway exists in human NDs, particularly in amyotrophic lateral sclerosis and multiple sclerosis. Together, our results uncover a previously unknown mechanism that links the CNS and peripheral immune cells to promote neurodegeneration.

关键词： neurodegenerative diseases disease-associated microglia γδ T cells reactive astrocyte IFN-γ C3

Electron mass enhancement and magnetic phase separation near the Mott transition in double-layer ruthenates

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Frontiers of physics 2018年第4期13卷 159-165页

作者： Jin peng x. M. Gu G. T. Zhou W. Wang J. y. Liu yu Wang Z. Q. Mao x. S. Wu Shuai Dong School of Physics Southeast University Nanjing 211189 China Collaborative Innovation Center of Advanced Microstrucutres Lab of Solid State Microstructures School of Physics Nanjing University Nanjing 210093 China Department of Physics and Engineering Physics Tulane University New Orleans LA 70118 USA

We present a detailed investigation of the specific heat of Ca3（Ru1-xMx）2O7 （M = Ti, Fe, Mn） single crystals. Depending on the dopant and doping level, three distinct regions are present： a quasi- two-dimensional metallic state with antiferromagnetic （AFM） order formed by ferromagnetic bilayers （AFM-b）, a Mott insulating state with G-type AFM order （G-AFM）, and a localized state with a mixed AFM-b and G-AFM phase. Our specific heat data provide deep insights into the Mort transitions induced by Ti and Mn doping. We observed not only an anomalous large mass enhancement, but also an additional term in the specific heat, i.e., C ∝ T2, in the localized region. The C ∝ T2 term is most likely due to long-wavelength excitations with both FM and AFM components. A decrease in the Debye temperature is observed in the G-type AFM region, indicating lattice softening associated with the Mott transition.

关键词： specific heat ruthenates Mort insulator phase separation

New progress of the miniaturized microwave ion source at Peking University

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Radiation Detection Technology and Methods 2023年第4期7卷 545-549页

作者： S.x.peng T.H.Ma W.B.Wu B.J.Cui A.L.Zhang y.x.Jiang Z.y.Guo J.E.Chen State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics Peking UniversityBeijingChina State Key Laboratory of Particle Detection and Electronics Department of Modern PhysicsUniversity of Science and Technology of ChinaHefei230026China

The generation of plasma in a microwave ion source involves confining electrons using a static magnetic field and energizing them with an electromagnetic field that transmitted into the plasma ***,according to electromagnetics theory,there is always a cut-off size in circular wave guides for a given *** a 2.45 GHz microwave,this dimension is 72 mm,which should theoretically prevent transmission of the microwave into the discharge chamber and no plasma can be *** 2006 Peking University(PKU)has successfully developed a series of permanent magnet 2.45 GHz microwave ion sources(PKU PMECRs)with a discharge chamber less than 50 mm,capable of delivering tens of mA beams for *** explain this anomalous phenomenon,a hybrid discharge heating(HDH)mode that combines surface wave plasma and electron cyclotron heating has been *** HDH mode not only successfully explains PKU PMECRs,but also predicts that the optimized inner diameter of the plasma chamber is 24 mm,which is confirmed by experiments involving different liners in the miniaturized microwave ion source.

关键词： Miniaturized 2.45 GHz ECR source Hybrid discharge mode Hydrogen plasma