SiC 粒子增强铝基复合材料界面行为研究

通过热力学和俄歇剖面分析，对用半固态溶液搅拌法制备的ＳｉＣｐ／Ａｌ－Ｃｕ复合材料的界面行为及其对湿润性的影响进行了研究．表明在ＳｉＣｐ／Ａｌ界面上发生了界面反应，界面反应的产物是ＭｇＯ和ＭｇＡｌ２Ｏ４．     

甲醇脱氢制备甲酸甲酯的催化性能研究

将浸渍法制备的Ｃｕ／ＳｉＯ２、Ｃｕ－ＺｎＯ／ＳｉＯ２、Ｃｕ－ＺｎＯ－ＺｒＯ２／ＳｉＯ２,以及Ｃｕ／γ－Ａｌ２Ｏ３、Ｃｕ－ＺｎＯ／γ－Ａｌ２Ｏ３、Ｃｕ－ＺｎＯ－ＺｒＯ２／γ－Ａ六种催化剂应用于甲醇脱氢制甲酸甲酯反应。实验结果表明,以Ａｌ２Ｏ３为载体的催化选择性较差且易积炭失活;加有ＺｎＯ助催化剂的Ｃｕ－ＺｎＯ／ＳｉＯ２性能优于末加助催化剂的Ｃｕ／ＳｉＯ２;加有权助催化剂的Ｃｕ－Ｚｎ－ＺｒＯ２／Ｓｉ     

SiCp—ZA22复合材料的结构与性能

研究了ＳｉＣｐ－ＺＡ２２复合材料的组织、界面关系及材料的常高温力学性能。结果表明,ＳｉＣ较均匀地分布于基体中,ＳｉＣ颗粒与基体结合良好且在ａ－Ａｌ界面上形成了少量Ａｌ２ＭｇＯ４过渡层;加入ＳｉＣ颗粒可明显提高材料的强度和弹性模量且高温下表现出较好的力学稳定性。     

Al2O3短纤维增强Al—Si合金复合材料的界面研究

本采用电子探针和扫描电镜分析Ａｌ２Ｏ３ｔ／Ａｌ－Ｓｉ合金复合材料的界面和拉伸断口形貌，发现界面处有Ｍｇ富集；Ａｌ－Ｓｉ合金很好地润湿Ａｌ２Ｏ３纤维，并形成共格、半共格混合界面，提高了界面结合强度；纤维被剪切断裂，无拔出现象。     

SiC晶须增强Al－2．0％Li合金的拉伸性能

研究了压力铸造法制备的ＳｉＣ晶须增强Ａｌ－Ｌｉ合金的时效硬化行为与拉伸性能．结果表明，ＳｉＣ晶须的引入不仅可以加速δ′相的长大，使时效峰提前，而且ＳｉＣ晶须的加入还明显提高Ａｌ－Ｌｉ合金的强度，而拉伸延伸率降低较少；ＳｉＣｗ／Ａｌ－Ｌｉ复合材料的拉伸断口呈穿晶韧窝状，不存在通常Ａｌ－Ｌｉ合金中因时效引起的断口形貌由穿晶型向沿晶型过渡的现象     

β-Sialon/SiC复合材料在冰晶石熔液中的腐蚀行为

探讨了β－Ｓｉａｌｏｎ／ＳｉＣ复合材料在冰晶石熔液中的腐蚀动力学规律、腐蚀机理及材料密度和碳化硅含量对其抗蚀性能的影响．研究发现，由于该复合材料中的β－Ｓｉａｌｏｎ相与冰晶石反应生成粘度较大的ＮａＡｌＳｉＯ＿４熔体能有效地阻止基体材料与冰晶石间的继续反应，抑制了腐蚀过程，使得β－Ｓｉａｌｏｎ／ＳｉＣ复合材料作为铝电解槽内衬侧壁的候选材料成为可能．     

SiC/Al_2O_3/Al-Si 复合材料的组织结构和性能

通过Ｘ－射线衍射、光学显微检验和扫描电子显微镜观察，研究了由Ａｌ－Ｍｇ－Ｓｉ合金高温直接氧化形成的ＳｉＣ／Ａｌ２Ｏ３／Ａｌ－Ｓｉ复合材料的相组成和显微结构，分析了工艺参数和材料显微结构对其力学性能的影响。实验结果表明，材料抗弯强度可高达５００ＭＰａ、断裂韧性达５．０８ＭＰａ·ｍ１２，致密度高达９８．４１％。     

反应条件对改性ZSM—5催化裂化性能的影响

将ＳｉＯ２／Ａｌ２Ｏ３＝２５．４６的ＮａＺＳＭ－５沸石用ＨＣｌ，ＮＨ４ＣＸｌ，ＬａＣｌ３进行了改性，并对改性样品进行水热处理。用正十六烷裂解反应考察改性样品水热处理后的催化性能，并研究了反应条件对正十六烷裂解活性和选择性的影响。     

NaCl的层厚度对NaCl—Si（111）界面电子特性的影响

根据Ｙａｎｉｖ的界面理论，利用紧束缚近似下的格林函数方法，研究了绝缘体ＮａＣｌ的层厚度对ＮａＣｌ－Ｓｉ（１１１）界面电子特性的影响。结果表明，（１）Ｓｉ上覆盖一层ＮａＣｌ时，导致局域在Ｓｉ－边的价带态密度显著降低和导带态密度显著升高，这可能是由于ＮａＣｌ的离子性将Ｓｉ的价带电子排斥到导带的缘故；（２）当ＮａＣｌ层厚增加时，局域在Ｓｉ－边的态密度几乎不受影响，这与ＮａＣｌ－Ｓｉ（１１１）界面热垒形成     

增强体颗粒尺寸对SiCp/2124Al复合材料变形行为的影响

利用常规静态单向拉伸技术,研究了ＳｉＣ颗粒尺寸对用粉末冶金工艺制得的ＳｉＣ颗粒增强２１２４Ａｌ合金（ＳｉＣｐ／２１２４Ａｌ）变形行为和力学性能的影响。在体积比为２０％的条件下,ＳｉＣ颗粒尺寸在０．２～４８μｍ的范围内变化,无论室温还是３００℃,材料的变形行为和拉伸力学性能明显取决于ＳｉＣ颗粒尺寸。研究表明,材料中的空隙密度、ＳｉＣ颗粒的间距、分布状态以及ＳｉＣ颗粒的断裂、ＳｉＣ颗粒／Ａｌ界面的脱粘     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

正~~