Determination of interface properties between micron-thick metal film and ceramic substrate using peel test

Peel test measurements have been performed to estimate both the interface toughness and the separation strength between copper thin film and Al2O3 substrate with film thicknesses ranging between 1 and 15 mu m. An inverse analysis based on the artificial neural network method is adopted to determine the interface parameters. The interface parameters are characterized by the cohesive zone (CZ) model. The results of finite element simulations based on the strain gradient plasticity theory are used to train the artificial neural network. Using both the trained neural network and the experimental measurements for one test result, both the interface toughness and the separation strength are determined. Finally, the finite element predictions adopting the determined interface parameters are performed for the other film thickness cases, and are in agreement with the experimental results.

Microstructures of explosively consolidated rapidly solidified aluminum and Al-Li alloy powders

The microstructures and the characteristics of water-atomized, nitrogen gas-atomized Al powders and ultrasonic argon gas-atomized Al-Li alloy powder were investigated by means of metallography, SEM, Auger electron spectroscopy and X-ray diffraction techniques. Rapidly solidified powders were explosively consolidated into different sized cylinders under various explosive parameters. The explosively consolidated compacts have been tested and analysed for density microhardness, retention of rapidly solidified microstructures, interparticle bonding, fractography and lattice distortion. It is shown that the explosive consolidation technique is an effective method for compacting rapidly solidified powders. The characteristics of surface layers play a very important role in determining the effectiveness of the joints sintered, and the Al-Li alloy explosive compacts present an abnormal softening appearance compared to the original powder.

BONDING OF ALUMINA AND METAL USING BULK METALLIC GLASS FORMING ALLOY

Metal-alumina joints have found various practical applications in electronic devices and high technology industry. However, making of sound metal ceramic brazed couple is still a challenge in terms of its direct application in the industry. In this work we successfully braze copper with Al2O3 ceramic using Zr52.5Cu17.9Ni14.6Al10Ti5 bulk metallic glass forming alloy as filler alloy. The shear strength of the joints can reach 140 MPa, and the microstructrural analysis confirms a reliable chemical boning of the interface. The results show that the bulk metallic glass forming alloys with high concentration of active elements are prospective for using as filler alloy in metal-ceramic bonding.

电子封装中的不流动芯下材料力学性能和封装可靠性的研究

可控坍塌芯片互连（C4）技术可以实现高速、高密度、小外形的封装，因此日渐得到关注和发展。本文针对发展新一代c4技术所面临的不流动芯下材料的机械性能问题，采用具有不同填充颗粒含量的不流动芯下材料，通过对材料的机械性能的测试和分析以及有限元模拟，初步揭示了不流动芯下材料变形行为的特点，填充颗粒含量对芯下材料机械性能的影响，以及芯下材料机械性能和芯下材料工艺导致的颗粒沉积对封装可靠性的影响。首先在差示扫描量热仪（DSC）、热一力学分析仪（TMA）上对材料的固条件、热膨胀系数、玻璃化转变温度进行了测试，接着又在六轴微型试验机上对材料在不同温度和应变率下的应力一应变行为进行了测试。测试结果表明，所用材料的固化条件和玻璃化转变温度可以满足不流动芯下材料的性能要求，材料的热膨胀系数高于芯下材料理想的热膨胀系数值，材料中填充颗粒含量、温度、应变率等对材料的应力一应变行为有重要的影响。为了解芯下材料中填充颗粒含量对机械性能的影响，对不同颗粒含量材料在各测试温度和应变率下的杨氏模量、屈服强度和流动应力进行了对比和分析。结果表明，在各测试条件下，芯下材料的杨氏模量基本随着颗粒含量的增加而升高；温度较低时，材料的屈服强度随颗粒含量的增加而升高，但是，较高温度时，材料的屈服强度和流动应力随着颗粒含量的增加呈现先升高后降低再升高的变化趋势。为理解芯下材料的屈服强度和流动应力随着颗粒含量非单调变化的行为，采用广义Eshelby等效夹杂法对含颗粒试样在单轴拉伸时试样内的应力分布进行了分析，并用纳米硬度计对材料纳米尺度的性能进行了测量。应力分析的结果表明，不流动芯下材料的SiO2填充颗粒的加入会在基体里引起应力集中，应力集中系数随着颗粒含量的增加先升高后降低，试样内的应力集中有使材料屈服强度降低的趋势。纳米硬度计的测试结果表明，芯～卜材料内形成了性能介于颗粒Z基体之间的界面相，界面相的形成有使芯下材料屈服强度提高的趋势。芯下材料屈服强度随着填充颗粒含量的非单调的变化是应力集中和界面效应藕合作用的结果。温度和应变率是影响芯下材料机械性能的重要因素。为刻画温度和应变率的效应，采用Pe化yna模型描述材料的应力一应变行为。结果表明，Per叮na模型可以拟合材料应变率相关的应力一应变行为，描述不流动芯下材料应力一应变曲线的基本趋势，对材料在测试范围外的行为给出较合理的预测，并且Perzyna模型可以很方便地用于ABAQUS中，这将易于工业应用。最后，采用商用有限元程序AB AQus分析了芯下材料机械性能和芯下材料工艺导致的填充颗粒沉积对C4封装可靠性的影响。结果表明，在芯片／基板的缝隙中填入芯下材料可以显著延长可控坍塌倒装封装焊点的热疲劳寿命，提高封装可靠性，可控坍塌倒装封装焊点的热疲劳寿命随着芯下材料中填充颗粒含量的增加而增长；芯下材料中填充颗粒在C4封装基板侧的沉积将导致封装焊点的热疲劳寿命缩短，而颗粒在芯片侧的沉积则可使焊点的热疲劳寿命稍稍延长。

Determination Of Interfacial Properties Between Metal Film And Ceramic Substrate With An Adhesive Layer

Peel test measurements and inverse analysis to determine the interfacial mechanical parameters for the metal film/ceramic system are performed, considering that there exist an epoxy interface layer between film and ceramic. In the present investigation, Al films with a series of thicknesses between 20 and 250 mu m and three peel angles of 90, 135 and 180 degrees are considered. A finite element model with the cohesive zone elements is used to simulate the peel test process. The finite element results are taken as the training data of a neural network in the inverse analysis. The interfacial cohesive energy and the separation strength can be determined based on the inverse analysis and peel experimental result. (C) 2008 Elsevier Ltd. All rights reserved.

Bonding Of Alumina And Metal Using Bulk Metallic Glass Forming Alloy

Metal-alumina joints have found various practical applications in electronic devices and high technology industry. However, making of sound metal ceramic brazed couple is still a challenge in terms of its direct application in the industry. In this work we successfully braze copper with Al2O3 ceramic using Zr52.5Cu17.9Ni14.6Al10Ti5 bulk metallic glass forming alloy as filler alloy. The shear strength of the joints can reach 140 MPa, and the microstructrural analysis confirms a reliable chemical boning of the interface. The results show that the bulk metallic glass forming alloys with high concentration of active elements are prospective for using as filler alloy in metal-ceramic bonding.

Heterorhabditidoides chongmingensis gen. nov., sp nov (Rhabditida : Rhabditidae), a novel member of the entomopathogenic nematodes

During a recent soil sample survey in Eastern China, a new entomopathogenic nematode species, collected from the Chongming Islands in the southern-eastern area of Shanghai, was discovered. Morphological characteristics of different developmental stages of the nematode combined with molecular data showed that this nematode is a new genus of Rhabditidae, and described as Heterorhabditidoides chongmingensis gen. nov., sp. nov., for that it shares more morphological characteristics with heterorhabditids than with ste-inernematids. For males, the papillae formula of bursa is 1, 2, 3, 3, with constant papillae number in the terminal group, stoma tubular-shaped and about 1.5 head width; cheilorhabdions cuticularized, esophageal collar present and long, median bulb present. For infective juveniles, EP = 90 (80-105) mu m, ES = 104 (92-120) mu m, tail length = 111 (89-159) mu m, and a = 19.1 (15-21). The percentages of the nucleotides A, T, C and G in the ITS1 regions of the new species are significantly different from those of heterorhabditids and other rhabditids. Molecular phylogenetic trees based on 18S rDNA and the internal transcribed spacer (ITS) sequences data revealed that the new entomopathogenic nematode species forms a monophyletic group, which is a sister group of the clade comprised of some genera of Rhabditidae. (c) 2008 Elsevier Inc. All rights reserved.

Potamothrix scleropenis sp nov (Oligochaeta : Tubificidae) from Fuxian Lake, the deepest lake in southwest China

Potamothrix scleropenis sp. nov. (Tubificidae: Tubificinae) is described from the profundal zone (74 m) of Fuxian Lake, the deepest lake (up to 155 m) on the Yunnan-Guizhou Plateau in China. The new species is assigned to Potamothrix because of its short vasa deferentia. and its tubular atria without ejaculatory ducts and prostate glands. It differs from congeners by its cuticularized penis sheaths; bifurcated, strongly curved spermathecal chaetae; bifurcated lower prongs of bifids; and feathered hairs. P scleropenis appears closely related to P cekanovskajae Finogenova, 1972 and P tudoranceai porka, 1994, since all the three species have homogeneous atria without prostate glands.

The toxic effects of microcystin-LR on embryo-larval and juvenile development of loach, Misguruns mizolepis Gunthe

Microcystin-LR, a specific and potent hepatotoxin, was tested for its effects oil loach embryo-larval and juvenile development, The results of this study showed that loach embryos were more sensitive when exposed to microcystin-LR at a later than at an earlier stage of development, Juveniles were far less sensitive to MC-LR than were embryos and larvae. Mortality and developmental abnormality were proven to be dose-dependent and to be stage-specific sensitive. Among the abnormal changes noted were: pericardial edema and tubular heart, bradycardia, homeostasis, poor yolk resumption. small head, curved body and tail, and abnormal hatching, Liver and heart were the main targets of microcystin-LR toxicity. Ultrastructural analysis documented a complex set of sublethal effects of microcystin-LR on loach hepatocytes, chiefly including morphological alteration in nuclear and RER of loach liver cells. fit addition, microcystin-LR was lethal to loach juvenile in the subacute (7 days) exposure (LC50) = 593.3 mug/l). (C) 2002 Elsevier Science Ltd. All rights reserved.

Inland free-living nematodes in China: A historical review of taxonomic studies with descriptions of Aphanonchus orientalis sp nov (Chromadorida : Leptolaimidae) and Daptonema limnobia sp nov (Monhysterida : Xyalidae)

The study of inland free-living nematodes is relatively imperfect in China, only seventeen papers were previously published. Since the early researches in 20-30s, few works have been accomplished until 80s. Altogether 171 taxa were formerly recorded, among which, over eighty species have been re-combined. A checklist of the former records with notes on their distribution is presented in this paper. Recently, the function of free-living nematodes has received much attention from Chinese zoologists. Hence, the present authors carried out their studies with emphasis on taxonomy of inland nematodes. During the survey of freshwater lakes, two species are found to be nem to science. Aphanonchus orientalis sp. nov. is characterized by having sclerotized vagina, the presence of 10-11 tubular supplements and 42-62 alveoli supplements in males, but no alveoli in females. Daptonema limnobia sp, nov. is distinguished from other species of the genus in the presence of larger and more anteriorly located amphids, shorter bifurcated spicules, smaller apophysis of gubernaculum, shorter terminal setae, and postvulval uterine sac in females.

Raman scattering of non-planar graphite: arched edges, polyhedral crystals, whiskers and cones

Planar graphite has been extensively studied by Raman scattering for years. A comparative Raman study of several different and less common non-planar graphitic materials is given here. New kinds of graphite whiskers and tubular graphite cones (synthetic and natural) have been introduced. Raman spectroscopy has been applied to the characterization of natural graphite crystal edge planes, an individual graphite whisker graphite polyhedral crystals and tubular graphite cones. Almost all of the observed Raman modes were assigned according to the selection rules and the double-resonance Raman mechanism. The polarization properties related to the structural features, the line shape of the first-order dispersive mode and its combination modes, the frequency variation of some modes in different carbon materials and other unique Raman spectral features are discussed here in detail.

Al2O3 : Cr3+ nanotubes synthesized via homogenization precipitation followed by heat treatment

Cr3+-doped NH4Al(OH)(2)CO3 nanotubes, templated by surfactant assemblies, were successfully synthesized via the homogenization precipitation method, and various crystallographic phase Al2O3:Cr3+ nanotubes were also obtained by postannealing at different temperatures. The characteristic R-1, R-2 doublet line transitions of ruby can be observed in the high crystalline alpha-Al2O3 nanotubes calcined at temperatures higher than 1200 degrees C. The results also indicate that the formation mechanism of the tubular nanostructures should result from the self-rolling action of layered compound NH4Al(OH)(2)CO3 under the assistance of the surfactant soft-template. The convenient synthetic procedure, excellent reproducibility, clean reactions, high yield, and fine quality of products in this work make the present route attractive and significant. Aluminum oxide nanotubes with high specific surface area could be used as fabricating nanosized optical devices doped with different elements and stable catalyst supports of metal clusters.

Surface morphology of ion-beam deposited carbon films under high temperature

Carbon films with an open-ended structure were obtained by mass-selected ion-beam deposition technique at 800degreesC. Raman spectra show that these films are mainly sp(2)-bonded. In our case, threshold ion energy of 140 eV was found for the formation of such surface morphology. High deposition temperature and ion-beam current density are also responsible for the growth of this structure. Additionally, the growth mechanism of the carbon films is discussed in this article. It was found that the ions sputtered pits on the substrate in the initial stage play a key role in the tubular surface morphology. (C) 2002 American Vacuum Society.

印刷线路板废弃物的热解与动力学实验研究

分别应用管式炉反应器和热重分析手段对印刷线路板废弃物的热解行为和热解动力学进行了实验研究。在管式炉中，研究不同的热解温度：700～950℃，对产物分布和气体成分分布的影响。实验结果表明：PCB热解气体的主要成分是H2和CO2，气体的热值较低，仅为2.09～5.41MJ/m^3，PCB不适合以气体产物为目标的能源利用方式。应用Friedman方法对PCB的热解动力学进行了研究，求得PCB的热解动力学参数分别是：表观活化能190.92kJ/mol，反应级数5.97，指前因子lnA47.14min^-1。

Design and operation of integrated pilot-scale dimethyl ether synthesis system via pyrolysis/gasification of corncob

The integrated pilot-scale dimethyl ether (DME) synthesis system from corncob was demonstrated for modernizing utilization of biomass residues. The raw bio-syngas was obtained by the pyrolyzer/gasifier at the yield rate of 40-45 Nm(3)/h. The content of tar in the raw bio-syngas was decreased to less than 20 mg/Nm(3) by high temperature gasification of the pyrolysates under O-2-rich air. More than 70% CO2 in the raw bio-syngas was removed by pressure-swing adsorption unit (PSA). The bio-syngas (H-2/CO approximate to 1) was catalytically converted to DME in the fixed-bed tubular reactor directly over Cu/Zn/Al/HZSM-5 catalysts. CO conversion and space-time yield of DME were in the range of 82.0-73.6% and 124.3-203.8 kg/m(cat)(3)/h, respectively, with a similar DME selectivity when gas hourly space velocity (GHSV, volumetric flow rate of syngas at STP divided by the volume of catalyst) increased from 650 h(-1) to 1500 h(-1) at 260 degrees C and 4.3 MPa. And the selectivity to methanol and C-2(+) products was less than 0.65% under typical synthesis condition. The thermal energy conversion efficiency was ca. 32.0% and about 16.4% carbon in dried corncob was essentially converted to DME with the production cost of ca. (sic) 3737/ton DME. Cu (111) was assumed to be the active phase for DME synthesis, confirmed by X-ray diffraction (XRD) characterization.