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Preparation and Characterization of Amorphous Layer on Aluminum Alloy Formed by Plasma Electrolytic Deposition(PED)

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材料热处理学报 2004年第05B期25卷 1084-1087页

作者： GUANYong-jun XIAYuan instituteofmechanics CASBeijingChina

In this investigation, protective layers were formed on aluminum substrate by Plasma Electrolytic Deposition (PED) using sodium silicate solution. The relation between the thickness of the layer and process time were studied. XRD, SEM, EDS were used to study the layer’s structure, composition and micrograph. The results show that the deposited layers are amorphous and contain mainly oxygen, silicon, and aluminum. The possible formation mechanism of amorphous [Al-Si-O] layer was proposed: During discharge periods, A12O3 phase of the passive film and SiO32"near the substrate surface are sintered into xSiO2(l - x)Al2O, and then transformed into amorphous [Al-Si-O] phase.

关键词：等离子电镀非晶形层铝合金 PED

Effects of the Spectral Line Broadened Model on the Performance of a Floing Chemical Oxygen—Iodine Laser

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Chinese Physics Letters 2002年第11期19卷 1628-1631页

作者：高智胡利民 instituteofmechanics ChineseAcademyofSciencesBeijing100080

A new gain saturation model of chemical oxygen-iodine lasers (COILs) is deduced from the conservation equations of the population number of upper and lower lasing levels. The present model is compared with both the Voigt profile function model and its low-pressure limit model. The differences between the Voigt profile function model or its low-pressure limit model and the model presented here are pointed out, such as the length of power extraction, the optimal range of the threshold gain. These differences are useful for the optimization of COIL adjustable parameters.

关键词： Chemical oxygen iodine lasers

Deformation Morphology underneath the Vickers Indent in Bulk Metallic Glasses

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Chinese Physics Letters 2005年第8期22卷 1994-1997页

作者：刑冬梅张泰华魏炳忧 StateKeyLaboratoryofNonlinearMechanics(LNM) InstituteofMechanicsChineseAcademyofSciencesBeijing100080//CollegeofPhysicsandElectronicInformationScienceTianjinNormalUniversityTianjin300072 StateKeyLaboratoryofNonlinearMechanics(LNM) InstituteofMechanicsChineseAcademyofSciencesBeijing100080 NationalMicrogravityLaboratory InstituteofMechanicsChineseAcademyofSciencesBeijing100080

Plastic deformation behaviour of Zr52.5Al10Ni10Cu15Be12.5 and Mg65Cu25Gd10 bulk metallic glasses (BMGs) is studied by using the depth-sensing nanoindentation and microindentation. The subsurface plastic deformation zone of the BMGs is investigated using the bonded interface technique. Both the BMGs exhibit the serrated flow depending on the loading rate in the loading process of indentation. Slow indentation rates promote more conspicuous serrations, and rapid indentations suppress the serrated flow. Mg-based BMG shows a much higher critical loading rate for the disappearance of the serration than that in Zr-based BMG. The significant difference in the shear band pattern in the subsurface plastic deformation zone is responsible for the different deformation behaviour between the two BMGs. Increase of the loading rate can lead to the increase of the density of shear bands. However, there is no distinct change in the character of shear bands at the loading rate of as high as 1000nm/s.

关键词： BMG Cu SEM

Marangoni-Bénard Instability with the Exchange of Evaporation at Liquid-Vapour Interface

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Chinese Physics Letters 2005年第2期22卷 402-404页

作者：刘荣刘秋生胡文瑞 instituteofmechanics ChineseAcademyofSciencesBeijing100080

A new two-sided model rather than the one-sided model in previous works is put forward. The linear instability analysis is performed on the Marangoni–Bénard convection in the two-layer system with an evaporation interface. We define a new evaporation Biot number which is different from that in the one-sided model, and obtain the curves of critical Marangoni number versus wavenumber. The influence of evaporation velocity and Biot number on the system is discussed and a new phenomenon uninterpreted before is now explained from our numerical results.

关键词：不稳定性液态-蒸汽表面蒸发交换温度差临界值

Effects of Adiabatic Exponent on Richtmyer-Meshkov Instability

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Chinese Physics Letters 2004年第9期21卷 1770-1772页

作者：田保林傅德薰马延文 LNM InstituteofMechanicsChineseAcademyofSciencesBeijing100080

We present a systematical numerical study of the effects of adiabatic exponent γ on Richtmyer–Meshkov instability (RMI) driven by cylindrical shock waves, based on the γ model for the multi-component problems and numerical simulation with high-order and high-resolution method for compressible Euler equations. The results show that the RMI of different γ across the interface exhibits different evolution features with the case of single γ. Moreover, the large γ can hold back the development of nonlinear structures, such as spikes and bubbles.

关键词： Shock waves

Shear Strength Measurements in LY-12 Aluminium Alloy During Shock Loading

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Chinese Physics Letters 2004年第4期21卷 707-708页

作者：戴兰宏阎敏沈乐天 StateKeyLaboratoryofNonlinearMechanics InstituteofMechanicsChineseAcademyofSciencesBeijing100080

Lateral stress of LY-12 aluminium alloy under plate impact shock loading was measured. Based on the measured data, the Hugoniot relation and shear strength were obtained. The result has demonstrated that the shear strength of the tested material increases remarkably with the increasing longitudinal stress. This means that the assumption of constant shear strength usually adopted in shock stress calculation is not suitable for the present material.

关键词： Stress analysis

Plasma-Particle Transfer Process with Phase-Changeand Chemistry Effects

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Journal of Thermal Science 1998年第2期7卷 97-103页

作者： WangBoyi TianWendong 等 instituteofmechanics ChineseAcademyofSciencesBeijing100080 instituteofmechanics ChineseAcademyofScie

A numerical model is proposed to analyze mass, momentum, and energy transfer between plasma andparticles in d.c. arc-heated and confined jet reactors at atmospheric pressure. It emphasizes the phasechange and thermal chemistry of particles and includes some other effects such as flow turbulence, gascompressibility and temperature-dependence of the transport properties under the plasma *** calculations for plasma-dissociated zircon process indicate the influences of reactor operationparameters on the plasma jet and particle behavior.

关键词： plasma-particle interaction transfer process turbulent jet phase change thermal chemistry numerical model

Heat Transfer from a dc Laminar Plasma—Jet Flow to Different Solid Surfaces

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Chinese Physics Letters 2003年第5期20卷 685-687页

作者： NENGXian PANWen-Xia WUCheng-Kang instituteofmechanics ChineseAcademyofSciencesBeijing100080

The heat flux distributions were measured by using transient method for an argon dc laminar plasma-jet flow impinging normally on a plate surface embedded with copper probes. Different powders were coated on the probe surfaces and the effect of powder coatings on the heat transfer from jet flow to the probe surface was examined. Experimental results show that the maximum values of the heat flux to the probe increase with the coating of fine metal powders, while for the surfaces coated with fine ceramic powders, the maximum values of heat flux decrease, compared with that to the bare copper probe surface.

关键词：等离子体涂层喷镀表面处理金属

An Experimental Study of Turbulent Flow in Attachment Jet Combustors by LDV

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Journal of Thermal Science 1993年第4期2卷 275-281页

作者： JUNLI CHENG－KANGWU instituteofmechanics ChineseAcademyofSciencesBeijing100080China instituteofmechanics ChineseAcademy

Flame stabilization in attachment jet combustors is based on the existence of the high temperature recirculation zone,provided by the Coanda effect of an attachment *** single attachment jet in a rectangular channel is a fundamental form of this type of *** this paper,the detailed characteristics of turbulent flow of a single attachment jet were experimentally studied by using a 2-D *** flowfield consists of a forward flow and two reverse *** forward one is composed of a curved and a straight *** curved section resembles a bent turbulent free jet,and the straight part is basically a section of turbulent wall jet.A turbulent counter-gradient transport region exists at the curved *** to the results,this kind of combustor should have a large sudden enlargement ratio and not too narrow in width.

关键词： attachment jet flame stability turbulent flow coherent structure