对极型高温超导直流感应加热装置电磁优化

基于高温超导（High Temperature Superconductivity,HTS）直流感应加热技术加热质量好、加热效率高等优点,提出一种基于圆筒形多极直流电机结构的对极铁芯高温超导直流感应加热装置.首先,针对加热装置气隙磁场与铝棒温升特性,采用麦克斯韦方程组与法拉第电磁感应定律,并结合固体热传导方程,建立铝棒加热过程数值模型;其次,兼顾加热装置环形铁芯与直流电机多极结构模式,构建4极与2极电磁模型与热模型;再次,针对铝棒电导率、转速以及长度对铝棒加热过程的影响,利用对极加热装置电磁热模型,研究铝棒内涡流与加热功率的变化过程;最后,针对加热区域磁场强度不足的问题,基于直流电机极靴长度对气隙磁场大小的影响,提出极靴结构改善气隙磁场模型.研究结果表明：2极铁芯结构下铝棒最大磁通密度高于4极结构0.16 T,铝棒最大温度高于4极结构54 K;铝棒内涡流密度和加热功率与铝棒电导率、长度以及转速呈正相关性;极靴结构提高了铝棒磁通密度0.11 T,铝棒温度提升了4.2℃.     

空气燃料比寻优技术在加热炉中的应用

分析了燃气加热炉热工特点，建立了热值前馈和烟气中氧含量反馈的空气燃料比寻优模型，并将模糊控制技术运用于所建立的空气燃料比寻优模型中．现场实际运行结果表明，使用该模型能合理地控制炉气的含氧量，提高钢坯加热质量，降低燃料消耗，取得了很好的效果．     

基于EES的Kalina循环系统优化设计

目前在世界各国中能源消耗主要依赖石油、煤炭、天然气等不可再生资源,各行各业在积极寻求新能源的同时也加大了对节能技术的研究来提高能源的利用率.具体到船舶运输业,由于燃料的利用率不超过50%,有的甚至不到30%,造成了能源的极大浪费.为了提高燃料总能量利用率,以柴油机排放的烟气余热为热源并结合Kalina循环技术,设计一种用于船舶烟气余热回收的Kalina循环动力系统,在此基础上对循环系统的性能做了优化设计,将Kalina动力循环系统与蒸馏系统耦合组成新的一级蒸馏Kalina动力循环系统,以便提高余热回收的利用率.     

基于EBSILON的冷热电三联供系统及能量利用特性

为研究天然气冷热电三联供分布式能源(combined cooling heating and power,CCHP)系统的能量利用特性,以某冷热电三联供能源站作为研究对象,利用EBSILON软件分别建立内燃机组、烟气-热水型溴化锂吸收式冷水机组、换热器组件等模型,分析了烟气-热水型溴化锂吸收式冷水机组在不同烟气与缸套水热源驱动下的制冷系数(coefficient of refrigeration,COP)特性,内燃机组不同负荷率下系统的综合供能特性.研究结果表明,CCHP采用单一热源制冷时,烟气热水型溴化锂吸收式冷水机组以烟气作为驱动热源可获得较高的COP,而以缸套水作为驱动热源时COP较低;在同时具备冷热负荷情况下,高温烟气更适合作为制冷热源,而高温缸套水更适合充当制热热源;采用双热源驱动制冷与单一热源相比,具有更高的综合能源利用效率,在内燃机75％负荷率、WY1工况下,COP与综合能源效率达到最大值1.28与92.0％;而在50％负荷率时采用缸套水作为单一热源驱动制冷机时,COP与综合能源利用效率达到最低值,分别为0.74与76.1％.模型分析得出的CCHP系统综合供能特性,在一定程度上可有效指导冷热电三联供能源站的高效运行.     

太阳能热泵热水系统辅助热源热经济分析

采用内燃发动机驱动的热泵作为太阳能热泵热水系统的辅助热源,从热力学和经济性两个方面对适合系统辅助热源使用的燃料进行了研究.定义了折算性能系数的概念,并用其衡量能量利用效率.确定了自变量,并分析了其对折算性能系数和一次能源利用率的影响,确定了自变量的影响度.研究表明,提高发动机和发电机效率,并回收利用发动机的余热是提高系统辅助热源能量利用率的根本措施.引入寿命周期费用法研究系统辅助热源的燃料费用,针对办公楼、住宅和宾馆3种典型建筑分析了燃料热值和价格对寿命周期费用的影响.综合考虑一次能源利用率和寿命周期费用,在不考虑燃料获取难度的前提下,得出在现阶段的条件下系统辅助热源应优先选用沼气和天然气作为其燃料的结论.     

不同海拔气体燃料燃烧和水温升特性实验研究

为研究在高海拔地区液化石油气燃料燃烧效率等问题,在海拔1000m至4500m的自然环境中,采用自制液化石油气燃烧试验装置并自行设计两种烧水壶进行实验研究.研究不同海拔、燃气流量、加热时间及水壶类型与沸点、水温升及温升速度之间的关系.结果表明,受海拔因素影响,燃料燃烧效率及热效率降低;海拔与水沸点、加热时间、温升速度及热效率具有对应的线性关系;不同海拔下,水加热时间与水温升之间线性相关;不同海拔地区,研究热水壶类型可以提高热效率.这为进一步提高高海拔地区燃料燃烧效率及热效率利用,居民环境改善具有现实意义.     

改进烟气加热刨花干燥机的探讨

<正>目前,国内刨花板工厂或车间使用的烟气加热刨花干燥机存在着两个缺点,即在操作过程中,未完全燃烧或带有明火的炭粒可能会污染刨花和引起失火。为了改进其性能,我们进行了四方面的试验: 1.在烟气发生炉内增设了一道挡火墙,显著改善了刨花污染程度,并避免了刨花与明火的直接接触, 2.分段制造干燥转筒,减少了中小型刨花板工厂在制造,安装和维修干燥机方面的困难; 3.干燥机使用了司·控硅无级调速,干燥转筒的转速可以在2—16(r.p.m)范围内调节; 4.增设了简易防火装置,保证干燥转筒内烟气温度始终低于刨花着火点。 这种经过改进的新型烟气加热刨花干燥机已经使用二年多时间,效率和性能都比旧式烟气加热刨花干燥机好。     

可调气隙高温超导直流感应加热样机仿真与实验

为了实现铝棒轴向温度分布的调节,设计了一台气隙结构可调的高温超导直流感应加热器,以在轴向上获取不同大小的磁场.通过调节加热器气隙结构进行均匀和梯度加热实验,分析双边调节与单边调节方式对加热效果的影响.验证可调气隙结构在调节加热工件轴向温度分布中的可靠性、有效性.同时利用有限元仿真软件对加热器样机进行建模,分析加热工件温度分布规律,从理论角度验证可调气隙结构的有效性.     

快速渗碳工艺的研究

以电阻对焊机和高频感应电炉为快速加热热源,研究试样在表面熔化与未熔化状态下的石墨快速加热渗碳及稀土元素对其催渗的作用,通过对金阻组织.显微硬度及渗层深度的对比分析可知,石墨快速加热渗碳能在较短的时间内,获得较深的渗碳层深度,具有一定的使用价值.     

金属氢化物导热系数测量

储氢材料是一类新的功能材料.研究它的导热性能,对于储氢材料使用时放氢所需的热源以及加热时间是十分重要的.通过稳态测量和非稳态测量理论分析,设计出相应的实验装置,探讨金属氢化物导热系数的测定.     

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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