Cr5Mo／A302异质焊头时效过程中的组织结构变化

利用光学显微镜对ＣｒＭｏ／Ａ３０２异质焊头在高温时效过程中的组织结构变化进行了研究。结果表明珠江体钢／奥氏体钢划质焊头中γ－Ｆｅ与α－Ｆｅ在熔合区有结晶相适应的结晶条件；增碳层与时效时间呈抛物线关系；时效中熔合区附近碳化物转变基本遵循Ｍ７Ｃ３→Ｍ２３Ｃ６→Ｍ６Ｃ；增碳层中析出碳化物与奥氏体基体保持共格关系。     

9Cr—1Mo—V—Nb耐热钢焊接接头组织分析

文章分析了９Ｃｒ－１Ｍｏ－Ｖ－Ｎｂ与几种常用耐热钢焊接接头的显微组织,表明试验的各种焊接接头的机械性能良好．各焊接接头回火后焊缝区的显微组织均为回火马氏体,这与９Ｃｒ－１Ｍｏ－Ｖ－Ｎｂ钢正火回火态的显微组织相类似,但晶粒相对粗大．９Ｃｒ－１Ｍｏ－Ｖ－Ｎｂ同类钢焊接接头过热区显微组织为回火马氏体,局部地区有少量δ铁素体．９Ｃｒ－１Ｍｏ－Ｖ－Ｎｂ钢与合金元素较低的异类钢焊接接头过热区的晶粒长大程度较同类钢为甚,碳化物聚集长大较显著．     

65Nb钢中的相关系研究

通过加热－冷却－组织分析法，研究了含铌基体钢６５Ｃｒ４Ｗ３Ｍｏ２ＶＮｂ（简称６５Ｎｂ）从１５００℃至室温不同温度下，钢所处的相区及不同冷速条件下相组成的变化，初步探讨了６５Ｎｂ钢中的相关系。     

Cu—20%Nb（纤维）／Sn复合材料低温预处理及Nb纤维富集的机理

用多种微结构分析方法及高温电阻方法研究了原位法制备的Ｃｕ－２０％Ｎｂ（纤维）／Ｓｎ复合材料在３５０￣４５０℃低温热处理中Ｎｂ纤维（等效于惰性标记）向背离Ｃｕ－Ｓｎ合金方向迁移并富集的机理。结果表明：Ｎｂ纤维的迁移和热处理过程中Ｃｕ／Ｓｎ扩散形成ε相时的体积膨胀有关。处于高度拉伸应变状态的Ｎｂ纤维在热处理过程中因应力释放而弯折或卷曲则为Ｎｂ纤维的移动提供了主要驱动力，使得其富集程度与温度有关。     

HSLA100钢的时效动力学

采用硬度法、透射电镜等方法研究了ＨＳＬＡ１００钢的时效动力学，结果表明，ε－Ｃｕ的析出动力学可用Ａｖｒａｍｉ方程来描述，时效过程表征激活能为１４０ｋＪ／ｍｏｌ，ε－Ｃｕ的粗化长大符合Ｏｓｔｗａｌｄ机制。     

ULCB钢中的冷变形与ε-Cu的脱熔行为

研究两种工艺的含铜超低碳贝氏体钢（ULCB）时效硬化行为,一种是直接固熔时效处理;一种是在固熔与时效处理之间进行一定量的冷预变形处理.实验结果表明,在一定的时效温度内,该钢的ε-Cu析出动力学曲线均会出现双峰甚至三峰现象.且经过预变形处理的钢,峰值出现的时间大幅度提前,峰值的高度也有明显的提高,在低温450℃时,预变形的这一作用更加明显.变形时效后,试验钢中的ε-Cu析出大量增加,且更加均匀.     

Cr5Mo钢管异种接头中碳迁移的研究

研究了Ｃｒ５Ｍｏ异种钢焊接接头在５００℃温度下长期运行后接头中各微区的组织变化、碳迁移后增碳层的变化规律。试验结果表明，焊态下无增碳层，运行后出现增碳层并依运行寿命的延长，增碳层中碳化物数量逐渐增多，碳化物颗粒变化大，并分布在含有较多位错线的板条铁素体基体上，对基中的Ｃｒ，Ｃ元素的分丰及含量进行了测定。接头的强度、硬度随碳迁移的增多无明显的变化。对接头微区的电极电位测量后，认为对接头的寿命无大影响     

富集性和亏损性A型花岗岩：以华北燕山和新疆乌伦古河地区岩石 …

华北燕山地区和新疆乌伦古河地区发育有过碱性Ａ型花册岩类。前者了出现于板内,富Ｎｂ,低εＮｂ而高εＳｒ;后者形成于造山晚期,贫Ｎｂ,高εＮｄ而低εＳｒ。总结了它们的地质学,岩石学,主要和痕量元素地球化学资料,报道了Ｒｂ－Ｓｒ和Ｓｍ－Ｎｄ同位素分析结果;     

电镀液和电镀层中铜和锰的联合测定

当ｐＨ＝１０时,铜和锰都能与ＰＡＲ生成稳定的红色络合物;当ｐＨ＝７时,锰与ＰＡＲ几乎不络合,而铜与ＰＡＲ则可以稳定络合．利用这种差异,可以在ｐＨ＝１０的介质中测定铜和锰的合量,而在ｐＨ＝７的介质中测定铜的量,再由两者之差求得锰的含量．试验表明,ｐＨ＝１０．０时,εＣｕ－ＰＡＲ４９８．５＝４．６６×１０４Ｌ／ｍｏｌ·ｃｍ;εＭｎ－ＰＡＲ４９８．５＝８．００×１０４Ｌ／ｍｏｌ·ｃｍ;ｐＨ＝７．０时,εＣｕ－ＰＡＲ４９８．５＝４．２６×１０４Ｌ／ｍｏｌ·ｃｍ．相对标准偏差小于３％,回收率为９５％～１０１％．其方法适用于电镀液和电镀层中Ｃｕ和Ｍｎ的测定     

微晶CuCr材料的制备及电击穿性能的研究

根据真空断路器大功率、小型化发展趋势对触头材料的要求，探索用高能球磨制粉、热压烧结的方法制备微晶ＣｕＣｒ触头材料．结果表明，高能球磨能够制备出超细晶Ｃｕ－Ｃｒ合金粉．７５０℃热压时材料仍保持合金粉形貌，颗粒内发生部分过饱和固溶Ｃｕ与Ｃｒ的时效析出过程．９２０℃热压时Ｃｕ与Ｃｒ组元重新分布并发生了再结晶过程，晶粒尺寸为２～３μｍ，远远小于常规方法生产的ＣｕＣｒ材料．由于微晶ＣｕＣｒ材料中Ｃｒ相固溶度升高，使材料电击穿机制发生变化，首次击穿相从常规材料中的Ｃｒ相转移到Ｃｕ相上．     

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.     

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     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

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

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