结构钢疲劳裂纹扩展门槛值预测的新方法

通过对各种疲劳门槛值的理论模型的分析，认为结构钢的拉伸性能指标和循环加载条件是裂纹体疲劳门槛值的决定因素．建立了用屈服强度、抗拉强度、断裂延性和循环加载应力比预测疲劳门槛值的人工神经网络模型，并用10种结构钢的60个样本对该模型进行了训练．结果表明，人工种经网络模型可以很好地描述疲劳门槛值与结构钢拉伸性能指标及应力比之间复杂的定量关系．应用所训练的人工神经网络模型预测了部分结构钢的疲劳门槛值，预测的结果与实测值符合良好。     

轴承钢的产皮劳裂纹研究

对轴承钢的产皮劳裂纹和门槛值进行了仔细研究。提出了该类材料门槛值的理论计算公式，考虑了如应力比，应力集中，曲率半径等影响脆性开裂的主要因素，并给出了实验验证，两者非常吻合。     

计算机控制测定门坎值的新方法

阐述了用新型ＡＭＳＬＥＲ高频疲劳试验机，结合计算机控制测定材料门槛值△Ｋｔｈ的新方法，该方法通过在恒应力比Ｒ下疲劳一定周次后，频率下降不超过某一特定值，从而得到门槛值△Ｋｔｈ。     

汽车静态侧翻门槛值的计算方法

文章介绍了一种汽车静态侧翻门槛值的计算方法，该方法考虑了悬架和轴的侧倾以及悬架组合侧倾角刚度和轮胎垂直刚度，具有较高的准确性。同时推导了侧翻门槛值的两种简化计算方法，以评估汽车的侧倾稳定性。     

1420铝锂合金的疲劳裂纹扩展和自抑制

研究了１４２０铝锂合金在２种不同应力比（０．１和０．７）下的疲劳长裂纹扩展特性和闭合效应，测量了裂纹扩展的门槛值和闭合力．虽然１４２０合金具有较低的本征门槛值，然而在低应力比下却呈现出优良的疲劳裂纹扩展特性，表现在低应力比下较高的疲劳门槛值和近门槛区裂纹扩展的自抑制．从实验的角度探讨了该合金“自抑制”现象产生的原因，指出这种作用主要来源于外韧化作用，包括分层韧化作用和晶体学扩展路径导致的高的裂纹闭合效应     

岩石扩容现象与超声横波特征参数相互关系研究评述

介绍了岩石扩容现象与超声皮特征参数相互关系相关专业领域研究的现状及其应用，在用横波速度最大值（Vsmax）来分析岩石微裂纹初始扩展时的应力值（应力门槛值）新方法的基础上，建议利用主动的人工横波震源，应力门槛值、Vsmax后的横波速度值与岩石裂纹加速发展的同步减小特性，更深入地进入地震破裂丛集及前兆特征的研究，有可能建立地震和地质灾害性预报的新方法，并提出利用利用传统方法研究岩石扩容机理，应力门槛值，泊松比等的同时，进行岩石扩容现象，声发射和超声波横波等特性参相互关系研究的新思路。     

结构钢疲劳裂纹扩展门槛值预测的新方法

通过对各种疲劳门槛值的理论模型的分析 ,认为结构钢的拉伸性能指标和循环加载条件是裂纹体疲劳门槛值的决定因素 .建立了用屈服强度、抗拉强度、断裂延性和循环加载应力比预测疲劳门槛值的人工神经网络模型 ,并用 1 0种结构钢的 60个样本对该模型进行了训练 .结果表明 ,人工神经网络模型可以很好地描述疲劳门槛值与结构钢拉伸性能指标及应力比之间复杂的定量关系 .应用所训练的人工神经网络模型预测了部分结构钢的疲劳门槛值 ,预测的结果与实测值符合良好     

声发射在研究岩石古温度中的应用

利用岩石的热Ｋａｉｓｅｒ效应探讨了我国９个地区的部分岩石的门槛温度，获得了它们的古地质温度值。实验取得的盘石包体的热声发射门槛温度值与地质温度计测得的该包体温度值十分吻和。     

汽车静肪侧翻门槛值的计算方法

文章介绍了一种汽车静态侧翻门槛值的计算方法，该方法考虑了悬架和轴的侧倾以及悬架组合侧倾角刚度和轮胎垂直赐度，具有较高的准确性。同时推导了侧翻门槛值的两种简化计算方法，以评估汽车的侧倾稳定性。     

一种确定压电传感器位置的拓扑优化方法

基于可观矩阵奇异值单元灵敏度的思想，提出了确定智能压电传感器安放位置的一种拓扑优化方法。为了获得智能结构压电传感器的优化位置，首先采用有限元方法对原系统进行了特征问题分析；第二利用奇异值分解法讨论了智能结构模态可观性的度量问题；第三推导了可观矩阵奇异值单元灵敏度公式；第四以奇异值单元灵敏度作为度量和准则并且给出一个门槛值，根据门槛值可以确定压电传感器优化位置；最后利用算例来说明本文方法的有效性。     

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

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