在线诊断中离心式压缩机预期性能计算

鉴于离心式压缩机运行性能在线诊断中预期性能的计算极为重要，而对于运行中工作元件发生变化引起性能的变化尚无较好的计算方法，特别是在许多情形下压缩机的结构参数不全时更难于计算，提出将对压缩机段的热力计算简化成为一个中国平均级的计算方法；     

活塞式压缩机热力计算的新方法——工作过程的计算机模拟

本文提供的新方法是在热力学基本方程的基础上,综合考虑影响压缩机各工作过程的诸因素(如:传热、泄漏、气流脉动、气阀运动规律等),建立了数学模拟方程,采用数值计算方法,在计算机上求解压缩机工作过程中热力参数的变化规律,以及压缩机的宏观热力性能(排气量、功率及容积比能等)。计算结果与实测结果较一致,证明了所提供方法的正确性及实用性。     

IGCC 系统蒸汽岛热力性能评估的模块化通用计算软件

应用模块化建模思想,建立了用于整体煤气化联合循环（ＩＧＣＣ）系统中余热锅炉与蒸汽轮机子系统（即蒸汽岛）热力性能计算与评估的理论模型,并开发了相应的模块化通用计算软件。此计算软件可用于对国外引进的ＩＧＣＣ系统的余热锅炉与蒸汽轮机子系统的热力性能进行分析与评估;也可用于ＩＧＣＣ系统中余热锅炉与蒸汽轮机子系统的方案设计计算与方案论证。应用所建立的软件,对国外设计的若干ＩＧＣＣ系统进行了热力性能分析与评估,结果表明所开发的软件具有一定的工程应用价值。     

制冷剂充注量对太阳能热泵热水器性能的影响

在建立太阳能集热/蒸发器和冷凝器的分布参数均相流动数学模型、压缩机和热力膨胀阀的集总参数数学模型和系统充注量模型的基础上,编制了直接膨胀式太阳能热泵热水器系统性能模拟程序.将模拟计算值和实验值进行了对比.基于此模型计算了不同充注量下系统的运行参数和性能参数,分析了充注量变化对加热时间、集热器出口过热度、蒸发压力、冷凝压力、压缩机功率、集热器集热效率及系统性能系数等的影响,指出了确定系统最佳充注量需考虑的主要因素.     

等β角对称圆弧型线的涡旋压缩机几何模型

针对基于等β角对称圆弧型线的涡旋压缩机建立了通用的几何模型，推导出了修正部分的工作腔容积、吸气孔口面积、泄漏线长度和工作腔换热面积随转角变化的计算公式，并假定修正部分的泄漏线为渐开线，起始展开角为涡旋线的起始展开角．通过解析几何的方法求取排气孔口和轴向力作用面积的各个顶点坐标，并沿其边界积分，从而精确地计算出它们的面积．所建立的通用几何模型可直接用于涡旋压缩机热力和动力模型的计算，为优化设计奠定了基础，运用通用几何模型对一台样机进行热力和动力计算，得到了合理的计算结果．     

基于MATLAB的多列往复式压缩机热力计算程序开发

为了快速高效地计算多列往复式压缩机热力参数,开发了基于MATLAB的多列往复式压缩机热力参数计算程序.以6M25A压缩机为例开展了热力计算,计算结果与厂家提供的热力参数相吻合.基于论文设计的热力计算程序,开展了压缩比、绝热指数对压缩机相对指示功损失的影响规律研究,获取了相对指示功损失随压缩比、绝热指数的变化曲线.研究结果表明:压缩机相对指示功损失随着压缩比的增大而减小,随着绝热指数的增大而增大;压缩比是影响压缩机相对指示功损失的主要因素.     

直线双缸压缩机的特性计算

为了提高制冷设备如空调、冰箱等的制冷效率,设计了一种直线双缸压缩机,介绍了其主要结构和工作原理。用LAWSON法对直线双缸压缩机的磁路数学模型和活塞运动数学模型进行了计算求解。计算结果表明:压缩机排气量能够满足所设定的制冷量的要求,效率较高,理论上运行会比较平稳。还分析了压缩机各个参数,如动子质量、频率等对其工作性能的影响,发现压缩机处于共振状态时具有最高工作效率。计算结果为压缩机的参数确定提供了参考依据。     

喷油螺杆压缩机指示图的试验研究

为了深入了解压缩机内部的微观工作过程,从而给压缩机参数的优化设计提供可靠的试验依据,通过安装在阴转子齿根处的压力传感器,测同从吸气过程中段至排气过程完毕时基元容积中压力的变化,得到了压缩机的一个基元容积内气体工作过程的指示图,通过比较不同工况下的指示图及相应的热力性能,分析了排气压力,转速及喷油量等设计参数对喷油螺杆压缩机热力性能的影响,研究结果表明：在较宽广的排气压力范围内,指示图上并未出现明显的等容压缩,转速对指示图及热力性能的影响不大,喷油量控制在压缩机容积流量的1％－2％时,压缩机性能较优;为了避免排气过程末期明显的压力突升现象,应在排气端盖上设置导流槽。     

螺杆压缩机设计计算软件的研究与开发

介绍了所开发的以Windows为操作平台的螺杆压缩机设计计算软件SCCAD,总结了SCCAD软件中转子型线、几何特性、热力性能、转子受力、转子变形以及刀具刃形等设计内容的计算方法和计算机程序,给出了利用VisualBasic语言设计的用户界面和后处理程序.SCCAD软件克服了传统设计方法设计周期长、计算准确度差的缺点,设计人员可通过该软件,采用建立在工作过程数学模拟基础上的螺杆压缩机设计新方法.利用SCCAD软件设计的螺杆压缩机的研制成功,证明了该软件的可靠性     

制冷压缩机热力性能的模糊建模方法

压缩机热力性能的准确计算，对使用压缩机的制冷空调装置的优化设计很重要。提出了预测压缩机热力性能的模糊建模方法，对比研究了单纯的模糊建模与基于理论模型的模糊建模两种方法的效果，结果表明，基于理论模型的模糊建模方法具有更好的预测精度和泛化能力。     

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