含氮奥氏体钢时效析出Cr2N的数值模拟

研究Fe-24Mn-18Cr-3Ni-0．6N高氮奥氏体钢在1023～1223K温度范围内时效过程中Cr2N的析出规律。根据析出相变热力学和动力学建立Cr2N析出的定量计算的数理模型。利用人工神经网络进行计算和验证，结果是满意的。该数学模型可用于高氮奥氏体钢时效Cr2N析出的计算设计和预测。     

低温奥氏体钢及其断裂机理的研究进展

综述了低温奥氏体钢的研究进展。论述了高锰、高氮奥氏体钢低温脆断模式及其断裂机理，指出不同合金化的高锰、高氮奥氏体钢有着不同的层错能、相变临界分切应力、解理强度、屈服强度，因而有不同的断裂现象，包括晶间开裂、穿晶脆断、退火孪晶界开裂。着重探讨了穿晶脆断现象，指出穿晶脆断是高锰含氮奥氏体钢特有的脆性断裂形式，提出了今后的研究方向。     

高氮钢相变及重熔过程的在线观察

在高温、低压或真空状态下高氮钢中的氮会释放出来,常压氮气氛中高氮钢的焊接也会引起氮的损失.利用共聚焦激光扫描高温显微镜对几种高氮钢的高温相变以及重熔时氮的释放进行了在线观察.观察到Fe-12Cr-0.276N的γ-δ相变、Fe-20Cr-8Mn-0.853N的α-γ相变、Fe-19Cr-15Mn-0.576N的γ-δ相变,验证了计算相图的正确性.观察到液态高氮钢熔化时氮气泡上浮到钢液表面、游动和破裂.根据观察到的氮气泡最大直径和液态不锈钢的表面张力,估算了气泡破裂前期内部的氮气压力.共聚焦激光扫描高温显微镜的在线观察适于发现热效应小的相变发生,并能测定新相的尺寸变化和气泡直径,可以弥补DTA/DSC等高温热分析手段的不足.     

低温奥氏体钢及其断裂机理的研究进展

综述了低温奥氏体钢的研究进展 论述了高锰、高氮奥氏体钢低温脆断模式及其断裂机理 ,指出不同合金化的高锰、高氮奥氏体钢有着不同的层错能、相变临界分切应力、解理强度、屈服强度 ,因而有不同的断裂现象 ,包括晶间开裂、穿晶脆断、退火孪晶界开裂 着重探讨了穿晶脆断现象 ,指出穿晶脆断是高锰含氮奥氏体钢特有的脆性断裂形式 提出了今后的研究方向     

低温奥氏体钢韧度计算设计

研究了低温奥氏体钢的韧脆转变规律和三个重要特征参数：室温冲击韧度A^300KV,韧脆转变温度和韧脆转变曲线斜率Kc，根据实验结果，经计算机处理得到定量计算式：A^300KV=f(Me),AKV(J)=A^300KV^exp[-B(300-TK/300)^2]，B是合金元素和温度的函数，经验证，计算结果是满意的，可应用于低温奥氏体钢的冲击韧度计算和设计。     

10Cr21Mn16NiN高锰氮奥氏体不锈钢组织与性能研究

研究了固溶处理温度对热轧态10Cr21Mn16NiN高锰氮奥氏体不锈钢微观组织、力学性能和腐蚀性能的影响,并进一步揭示了该材料的低温韧脆转变行为。结果表明,随着固溶温度的升高,屈服强度和抗拉强度逐渐降低,而延伸率和耐腐蚀性能逐渐增大。这是因为高温固溶促进了热轧阶段形成的有害相重新溶解,从而消除析出相对性能带来的不利影响。10Cr21Mn16NiN钢在低温冲击载荷下表现出明显的韧脆转变行为,韧脆转变温度在-110℃附近,高于-110℃可以获得强度与韧性的良好配合。     

Ti和Nb对18Cr-2Mo铁素体不锈钢韧脆转变温度的影响

通过真空冶炼、锻造、热轧和退火试验制备出18Cr-2Mo铁素体不锈钢,结合其冲击试验和透射电子显微镜、扫描电子显微镜及电子背散射衍射等分析结果探讨了Ti和Nb微合金化对其韧脆转变温度的影响.结果表明：在C和N含量较低的条件下,添加微量元素Ti和Nb可以显著降低18Cr 2Mo铁素体不锈钢的韧脆转变温度（降低约40 °C）,并改变热轧后的织构类型而形成(001)和(111)复合织构;通过合适的退火工艺处理,可进一步提高其冲击韧性;在热轧过程中,产生细小弥散的Ti（N, C）和Nb（C, N）相是复合织构形成的主要原因.     

18%Cr-12%Mn-0.55%N高氮奥氏体不锈钢低温性能与组织稳定性

研究了高氮奥氏体不锈钢18%Cr-12%Mn-0.55%N在室温和低温下的力学行为和组织稳定性,并对实验钢的断裂失效行为进行了讨论.低温冲击实验结果表明,实验钢在-70℃前后存在韧脆转变现象,这种脆性类解理断裂是在奥氏体的{111}面发生的;低温拉伸实验结果表明,该钢室温拉伸时即有相变发生,相变产物除α′马氏体外,还发现了一种不同于α′马氏体的相变产物,其结构和相关参数暂不能确定.基于冲击实验和拉伸实验结果可以认为,该钢在-60℃以上有很好的强度和塑性结合,因此其使用温度应该在-60℃以上.     

氢致开裂的TEM原位拉伸观察与研究

通过对颈充氢３１０不风薄膜在透射电镜（ＴＥＭ）下的原位拉伸观察，并和不含氢试样的结果相比较，研究了氢在韧－脆转变中的作用及氢致脆断机理，结果表明，氢使奥氏体不锈钢由韧变脆的根本原因是氢降低了微裂纹形核时的临界应力强度因子，从而抑制ＤＦＺ中纳米级微裂纹向空洞的转化。     

输油管线钢焊接粗晶区韧脆规律的研究

系统研究了粗晶区在不同焊接热过程中的韧性分布特征和控制韧性的显微组织因素．基于示波冲击试验提供的动态断裂信息，提出了几种新的评定管线钢韧脆转变温度的准则．     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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     

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