大型汽轮发电机组基础动力特性灵敏度分析

利用空间梁单元建立汽机基座的动力学分析模型,并运用有限元数值模拟,对发电机框架式基础动力特性进行灵敏度分析,讨论汽机基座动力特性影响因素的敏感程度.结合国内某大型汽轮发电机组基础进行优化设计,得到了动力特性优良的汽机基座方案.通过与模型试验结果相比较,验证了有限元数值模拟的准确性和可行性.     

以二氧化碳作介质的冷凝汽轮机排汽的节能分析

以100 MW 高压凝汽式汽轮机发电机组为例,对采用以二氧化碳为介质的带膨胀机的排汽冷凝系统进行了循环过程的热力计算,得出这种系统通过二氧化碳膨胀机回收汽轮机排汽中的部分能量,不仅能够减少汽轮机系统的冷源损失,还能减少冷却水的消耗量,减少系统运行的动力消耗,并与现在常用的汽轮机排气冷却水系统在热效率、冷却水用量、冷却水系统用电量等方面进行了对比分析。     

液压基座平台的振动控制方程与动力响应

将液压基座平台上部装置简化为一个质量单元，考虑平台的刚体运动和液压控制系统的耦合，建立了平台系统的运动控制方程。根据平台受迫后运动的稳定条件和工程控制理论，提出了液压系统反馈流量系数的计算条件，应用Laplace变换，提出了时域和频域内平台动力响应计算方法。应用该方法设计了平台的控制系统并计算了平台的动力响应。结果表明，该方法可以有效提高平台动力 稳定性和减小平台振动。     

矩形反应器的速度分布和质量输运

本文将Andrew对水平基座的矩形反应器的速度分布和质量输运的分析推广到有小角度的倾斜基座反应器上,计算了不同倾角时各截面的速度分布,分析了外延层厚度均匀性、基座宽度利用率与反应器几何参数之间的关系。最后通过引入质量输运系数校正因子,计算了倾斜基座上纵向生长速率,分析和计算结果与生产中的测试结果基本吻合。     

汽轮机启停过程中的轴胀数学模型

汽轮机启停过程中的轴胀数学模型胥建群，曹祖庆（东南大学动力工程系，南京２１００１８）在电站仿真系统中，汽轮机差胀模型是很重要的一部分，而差胀模型又离不开轴胀模型。以往用有限元计算的轴胀模型，精度虽然比较高，但模型复杂计算周期长。以致很难达到仿真实时性...     

预应力对基座振动特性的影响分析

设备安装引起的预应力会影响基座的振动特性。基座主要由梁板结构组成,该文首先从理论推导出发分析了预应力对简支梁、板固有频率及导纳的影响,并验证了有限元方法计算预应力结构振动特性的准确性;然后利用有限元方法计算了预应力对加筋板结构振动特性的影响,最后分别计算分析了设备安装对刚性台架上的淡水泵基座以及对实艇浮筏基座振动特性的影响。结果表明预加载荷对梁板结构低频振动特性影响较为显著;设备安装对刚性台架上的淡水泵基座低频导纳峰值频率处的影响较为明显,尤其是跨点导纳;设备安装对实艇浮筏基座导纳的影响可以忽略。     

CVD反应器内复杂流动现象的有限元模拟

本文建立了用于计算立式钟罩CVD反应器内对流扩散现象的流体动力学和热输运方程,并用Galerkin有限元法做了计算(计算过程中考虑了热浮力对流动的影响)。计算结果表明,在热基座上方存在着涡旋运动,彻底消除这种运动比较困难,但适当地增加入流速度可使涡旋区远离基座表面,从而可消弱涡旋运动对薄膜生长均匀性的影响。     

小型背压式汽轮机性能计算软件开发

针对小型汽轮机性能定量研究相对缺乏的现状,开发了小型背压式汽轮机性能通用计算软件. 采用顺序和倒序的计算方法和模块化设计方法,以Windows为工作平台,运用Visual Basic 6.0软件开发工具研制开发,界面友好,适用性强,能满足小型背压式汽轮机性能计算要求,是汽轮机设计、改进和运行良好的辅助计算工具.     

汽轮机机械超速不合格原因分析及改进

兰州石化公司化肥厂动力车间2×18MW汽轮发电机组1#汽轮机已运行12年,在一次超速试验中危急保安器不动作,经过对相关部件检查,最终确定主要原因是危急遮断器螺钉松动,造成机械超速不合格。针对这种情况,通过计算危急保安的偏心距,不断调整螺钉在飞锤中的位置,并经过机械超速试验验证,最终解决了机械超速不合格的问题,保证了汽轮机的安全运行。     

基于回热系统分析的汽轮机变工况热力计算

在传统汽轮机变工况计算原理的基础上提出了一种工程实用的变工况热力计算方案,并针对某300MW汽轮机进行了实施,完成了多个变工况下的热力计算.计算结果与已知该汽轮机变工况下蒸汽参数设计值的对比表明:方案切实可行,程序方便实用,计算精度能满足工程应用要求.     

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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