Wear resistance of reaction sintered alumina/mullite composites

Alumina and alumina/mullite composites with mullite content of 0.96-8.72 vol.% were subjected to an abrasive wear test under loads of 0.1-2.0 N with a ball-on-disc apparatus. The wear rate and area fraction of pullout f(po) on the worn surfaces were measured. The wear resistances of the alumina/mullite composites were better by a factor of 1-2 than that of pure alumina. The main wear mechanism of alumina is fracture wear, and for alumina/mullite composites, fracture wear and plastic wear mechanisms work together. The influence of mechanical properties on wear resistance was estimated by Evans' method. It was found that the wear rate depends on f(po), and the primary reason for the better wear resistance of alumina/mullite composites is the reduction off, induced by fracture mode transition. (c) 2007 Elsevier B.V. All rights reserved.

大豆超氧岐化酶和品质因素相关性研究

本文进行了大豆种子超氧岐化酶和大豆品质因素（脂肪酸）之间的相关性研究。在这一研究中，我们使用了三种方法：1、HPLC分离测定脂肪酸的组成。2、用聚丙烯酰胺凝胶电泳研究同功酶。3、建立了自旋捕捉方法分析超氧岐化酶的活性。我们对二十四种大豆进行了研究：虎林野生大豆、公主岭野生大豆、秣食豆、黑豆、金元1号、满仓金、小金黄、东农4号、大白眉、早丰1号、十胜长叶、阿姆索、九农9号、黑河3号、绥农4号、黑农26号、吉林3号、合丰23号、哈76-6296、辽宁3号、吉林20、铁丰18、长农4号和EVANS、结果表明大豆种子SOD的比活力和其油脂含量呈极显著负相关；和亚麻酸含量呈极显著正相关；和油酸含量呈极显著负相关；和棕榈酸含量呈显著正相关；和亚油酸含量基本无关；和不饱和脂肪酸和为负相关。其直线回归方程分别为：Yoil = 27.72270-193.04800X比活力 Y18:3 = 3.64289 + 86.69367X比活力 Y18:1 = 31.42366 - 206.61395X比活力 Y16:0 = 9.03986 + 73.46336X比活力 只考虑栽培大豆，它们均未达到5％的显著水平。同功酶的研究结果表明，同功酶可分三个谱带区：A、B和C区，A区为MN-SOO、B、C区均为Cu、Zn-SOD。其中：虎林野生大豆、公主岭野生大豆，秣食豆、黑豆均有两条Mn-SOD同功酶谱带，其余二十个品种栽培大豆均有一条。吉林3号、吉林20的B区只有一条Cu、Zn-SOD同功酶谱带，其余二十二种大豆均有三条。C区都为三条Cu、Zn-SOD同功酶谱带。A、B和C区的百分量和大豆含油量、脂肪酸进行相关分析。结果表明，只有栽培大豆的A区和亚麻含量为显著负相关，其它均没达到5％的显著水平。其直线回归方程为：YA = 43.3277 - 2.5481 X18:3对用HPLC分离脂肪酸的文献方法进行了改进，由文献的1小时改进到每个样品十八分钟。并对二十四种大豆的脂肪酸组成进行了分离测定，结果发现，野生大豆、半栽培大豆和黑豆的亚麻酸含量高于栽培大豆。对光照核黄素体系，DMPO捕捉O_2:的机理进行了探讨。通过SOD抑制O_2~-的DMPO捕捉加合物DMPO－OOH的生成，建立了用自旋捕捉方法分析SOD的活性，并对二十四种大豆种子SOD的活性进行了分析，结果发现，野生大豆，半栽培大豆和黑豆的SOD比活力偏高。

STRUCTURAL DEFECTS AND THEIR ELECTRICAL-ACTIVITY IN GERMANIUM IMPLANTED SILICON

The electrical and structural characteristics of secondary defects in regrown amorphous layers formed in n-type Si(100) with a resistivity of 2 OMEGA cm and 6 OMEGA cm using Ge+ ions, has been studied. The amorphous layers with a thickness of 460 nm are formed by implantation of 1 x 10(15) Ge+ cm-2 at an energy of 400 keV. Both conventional furnace and rapid thermal annealing were used to regrow the amorphous layer and the residual defects have been characterised in terms of their concentration depth distribution and activation energies using C-V and DLTS. Structural information has been obtained from RBS and XTEM. By choosing suitable anneal conditions it is possible to eliminate extended defects, apart from a low concentration of end of range dislocation loops. However, a substantial population of electrically active point defects remain after simple low thermal budget anneals. In a sample implanted with 1 x 10(15) Ge+ cm-2 at 400 keV a region of deep donors approximately 460 nm from the surface is always present When the samples are annealed at higher temperatures (> 850-degrees the total deep donor concentration is reduced by one order of magnitude. Other electrically active defects not observable in the low (750-degrees-C) temperature annealed layers become apparent during anneals at intermediate temperatures.

中国管口苔属（Solenostoma Mitt.）植物研究

本文是对中国管口苔属（Solenostoma Mitt.）植物种类的初步整理和研究。共记载3亚属、44种及1变种，其中有24个新组合，如下：Solenostoma (L.) subulatum (Evans) Wang, S. (L.) atrovirens (Schleich) Wang, S. (L.) grossitextum (Steph.) Wang, S. (S.) fusiformis (Steph.) Wang, S. (S.) lanigerum (Mitt.) Wang, S. (S.) pseudocyclops (Inoue) Wang, S. (S.) subrubrum (Steph.) Wang, S. (S.) pyriflorum var.minutissimum (Amak.) Wang, S. (S.) sinensis (Nich.) Wang, S. (S.) faurianum (Beauvd) Wang, S. (S.) cyclops (HAtt.) Wang, S. (S.) apressifolium (Mitt.) Wang, S. (S.) schaulianum (Steph.) Wang, S. (P.) Japonicum (Amak.) Wang, S. (P.) tetragonum (Lindb.) Wang, S. (P.) rosulans (Steph.) Wang, S. (P.) thermarum (Steph.) Wang, S. (P.) hattorianum (Amak.) Wang, S. (P.) rupicolum (Amak.) Wang, S. (P.) rubripunctatum (Hatt.) Wang, S. (P.) hasskarlianum (Nees) Wang, S. (P.) setulosum (Herzog) Wang, S. (P.) truncatum (Nees) Wang, S. (P.) tsukushiensis (Amak.) Wang, 其中有14种及1变种为中国分布新纪录，如下：Solenostoma (L.) grossitextum (Steph.) Wang, S. (S.) fusiformis (Steph.) Wang, S. (S.) faurianum (Beauvd.) Wang, S. (S.) cyclops (Hatt.) Wang, S. (S.) pusillum (Jens) Steph., S. (S.) pyriflorum var. minutissimum (Amak.) Wang, S. (P.) rubripunctatum (Hatt.) Wang, S. (P.) thermarum (Steph.) Wang, S. (P.) rosulans (Steph.) Wang, S. (P.) hyalinum (Lyell) Mitt., S. (P.) radicellosum Mitt, S. (P.) Japonicum (Amak.) Wang, S. (P.) tsukushiensis (Amak.) Wang, S. (P.) hatterianum (Amak.) Wang, S. (P.) rupicolum (Amak.) Wang, 其中还有6种中国特有种，如下：Solenostoma (L.) subulatum (Evans) Wang, S. (P.) flagellalioides Gao, S. (P.) microphyllum Gao, S. (P.) orbicularifolium Gao, S. (P.) setulosum (Herzog) Wang, S. (S.) sinensis (Nich.) Wang。本文还对管口苔属（Solenostoma Mitt.）的研究历史作了回顾。对中国管口苔属各分类群的鉴别特征、产地和地理分布作了叙述，对区系成份做了分析。并对前人工作中的某些问题进行了讨论，提出了自己的看法。

First principles based predictions of the toughness of a metal/oxide interface

We describe a first-principles-based strategy to predict the macroscopic toughness of a gamma-Ni(Al)/alpha-Al2O3 interface. Density functional theory calculations are used to ascertain energy changes upon displacing the two materials adjacent to the interface, with relaxation conducted over all atoms located within adjoining rows. Traction/displacernent curves are obtained from derivatives of the energy. Calculations are performed in mode I (opening), mode II (shear) and at a phase angle of 45 degrees. The shear calculations are conducted for displacements along < 110 > and < 112 > of the Ni lattice. A generalized interface potential function is used to characterize the results. Initial fitting to both the shear and normal stress results is required to calibrate the unknowns. Thereafter, consistency is established by using the potential to predict other traction quantities. The potential is incorporated as a traction/displacement function within a cohesive zone model and used to predict the steady-state toughness of the interface. For this purpose, the plasticity of the Ni alloy must be known, including the plasticity length scale. Measurements obtained for a gamma-Ni superalloy are used and the toughness predicted over the full range of mode mixity. Additional results for a range of alloys are used to demonstrate the influences of yield strength and length scale.

基于第一性原理的金属/氧化物界面结合强度与宏观韧性的系统性研究

<正>总结介绍作者们多年来发展的基于第一性原理的系统性研究金属/氧化物界面结合强度和宏观韧性的策略方法。以应用广泛的γ-Ni/α-Al_2O_3界面为例,从第一性原

First principles based predictions of the toughness of a metal/oxide interface

We describe a first-principles-based strategy to predict the macroscopic toughness of a gamma-Ni(Al)/alpha-Al2O3 interface. Density functional theory calculations are used to ascertain energy changes upon displacing the two materials adjacent to the interface, with relaxation conducted over all atoms located within adjoining rows. Traction/displacernent curves are obtained from derivatives of the energy. Calculations are performed in mode I (opening), mode II (shear) and at a phase angle of 45 degrees. The shear calculations are conducted for displacements along < 110 > and < 112 > of the Ni lattice. A generalized interface potential function is used to characterize the results. Initial fitting to both the shear and normal stress results is required to calibrate the unknowns. Thereafter, consistency is established by using the potential to predict other traction quantities. The potential is incorporated as a traction/displacement function within a cohesive zone model and used to predict the steady-state toughness of the interface. For this purpose, the plasticity of the Ni alloy must be known, including the plasticity length scale. Measurements obtained for a gamma-Ni superalloy are used and the toughness predicted over the full range of mode mixity. Additional results for a range of alloys are used to demonstrate the influences of yield strength and length scale.

四苯基丁二烯基稀土化合物的合成及其对丁二烯聚合的催化活性

稀土碳π键型化合物已得到广泛研究,而稀土碳σ键型化合物的合成却报道得较少。1970年Hart等人首次报道了稀土碳σ型化合物LiLn(C_6H_5)_4(Ln=Sc,Y,La,Pr)的合成,1981年Evans等人合成了稀土碳σ键型化合物[(C_5H_5)_2LnC(CH_3)_3](THF)(Ln=Er和Lu)。我们合成了如下两种新型四苯基丁二烯基稀土σ键化合物。相似的d-类化合物的晶体结构证实金属碳键为σ键型。研究了(Ⅰ)中的Nd化合物与三乙基铅配合对丁二烯聚合的催化活性。

Locating hexagonal and cubic phases in boron nitride using wavelength-selective optically detected x-ray absorption spectroscopy

Locating hexagonal and cubic phases in boron nitride using wavelength-selective optically detected x-ray absorption spectroscopy, D.A. Evans, A.R. Vearey-Roberts, N.R.J. Poolton Appl Phys Lett 89, (2006) 161107

Modification of GaAs Schottky diodes by thin organic interlayers

Modification of GaAs Schottky diodes by thin organic interlayers, A.R. Vearey-Roberts and D.A. Evans, Appl. Phys. Lett. 86, 072105 (2005)

Direct observation of Schottky to Ohmic transition in Al-diamond contacts using real-time photoelectron spectroscopy

Evans D A, Roberts O R, Vearey-Roberts A R, Langstaff D P, Twitchen D J and Schwitters M 2007 Direct observation of Schottky to ohmic transition in Al-diamond contacts using realtime photoelectron spectroscopy Appl. Phys. Lett. 91 132114 doi:10.1063/1.2790779