一种耐高温多层热防护组件结构设计与性能研究

研究了由多种功能层材料组成的热防护组件的结构设计方法与热防护性能.利用仿真计算模拟了高温热环境下由不同厚度的面板层材料与隔热层材料组成的热防护组件的热响应行为,并通过石英灯加热考核验证了优化设计的热防护组件的耐温隔热与可重复使用性能.结果表明,致密的面板层材料具有优异的耐温性能,而由气凝胶组成的隔热层材料具有极低的热导率.根据目标环境匹配设计两种功能层材料厚度,可使多层热防护组件具备经最高温度1 600℃的加热考核后,背温仅为118℃的优异耐温隔热性能.      

高温环境中VMOS超声功率开关的性能分析

对采用ＶＭＯＳ功率器件构成的超声功率开关的开关性能和温度性能进行了分析，设计了应用于超声测井仪器中的实用功率发射电路，给出了实际电路的高温试验结果。结果表明，ＶＭＯＳ功率器件在高温环境下的多项性能指标均优于双极型功率器件，可靠性也更高。所给出的设计方法可供高温环境功率电路设计参考。     

飞机平台诱发环境温度的建模与仿真

飞机平台的诱发环境是机载设备的实际工作环境,诱发环境温度是影响机载设备工作的主要环境因素。针对飞机平台诱发环境温度的建模与仿真问题,分析了影响飞机平台诱发环境温度的主要因素,提出了以相似传热结构分类为基础的一种飞机平台诱发环境温度建模与仿真方法。将飞机平台相似传热结构分为翼形舱结构、环形舱结构、大舱室结构、开启舱结构和热防护结构,采用集中参数方法建立5种传热结构的通用热特性模型,以Modelica语言为工具建立了5种传热结构的通用热特性仿真模型。对飞机平台进行相似热区域划分,采用通用热特性仿真模型建立飞机整机的诱发环境温度仿真模型。以某型机为例,进行了诱发环境温度仿真计算,验证了建模与仿真的可行性。仿真表明,飞机飞行时机身区域舱内空气温度最高可达70℃,发动机舱内温度短时间内可达140℃,长时间工作在90℃~110℃之间,发动机热防护结构的最高温度可达160℃。     

高温环境中VMOS超声功率开关的性能分析

对采用ＶＭｔＯＳ功率器件构成的超声功率开关的开关性能和温度性能进行了分析，设计了应用于超声测井仪器中的实用功率发射电路，给出了实际电路的高温试验结果。结果表明，ＶＭＯＳ功率器件在高温环境下的多项性能指标均优于双极型功率器件，可靠性也更高，所给出的设计方法可供高温环境功率电路设计参考。     

燃料电池汽车整车热管理系统设计与仿真分析

以某款燃料电池汽车为研究对象,综合考虑车辆的整车布置环境和热管理要求,设计了一套完整的氢燃料电池汽车热管理系统;对关键零部件进行选型与性能匹配设计,运用AMESim软件搭建热管理系统一维仿真模型并进行可信度验证。通过冷却液输入流量、零部件进出水温度及温差等指标对不同工况下的氢燃料电池汽车热管理系统进行仿真分析,结果表明:除电堆和中冷器出水温度在峰值工况下达到极限值不宜长时间工作外,该系统其余工况均运行良好,满足设计要求,可为今后研发燃料电池汽车整车热管理系统提供一定设计思路。     

附加相变材料层的热防护服装传热数值模拟

火灾高温环境中,作业人员穿着防护服装可有效减小热压并提高着装舒适性.本文构建了模拟火灾环境下含相变材料的多层火灾安全防护服的传热模型,并利用热防护性能测试装置对模拟结果进行验证,计算与实验结果吻合良好.同时利用模型结果研究了防护性能与相变材料的熔点及相变层在服装层中的配置关系.研究发现与一般多层消防服相比,含相变材料层消防服在高温火灾环境下具有较好的防护性能,所选PCM的热物理属性,尤其是含PCM织物层在多层服装各层中的布置对服装防护人体皮肤烧伤性能影响较为显著.     

基于压电传感器的电荷放大测量电路的优化方案

从压电传感器的工作特点、适用范围和影响压电传感器工作性能的主要因素出发,在给出了压电传感器两种测量电路的基础上,进一步分析了电荷放大器测量电路的性能.提出设计一种差分放大形式的信号调理电路来减小干扰和漂移,通过EWB电子仿真软件对所设计的信号适调电路进行仿真,结果表明,差分放大形式的信号适调电路达到了预期的优化要求.     

发动机舱温度场仿真与分析

利用热网络法和流体网络法对发动机舱进行热仿真.建立了飞行器发动机舱各部件与其内外流体之间的网络关系及仿真模型,并进行耦合求解,得到此发动机舱各部件不同位置的温度分布.根据所得的数据对发动机舱各部件受热后对工作性能的影响进行分析,对非耐热部件的热防护与热控进行分析与设计,为使发动机各个部件能够在比较理想的环境下工作,提出了表面抛光、加隔热层以及组合隔热等3种优化方案并进行仿真.     

航空发动机静电传感器温度漂移特性分析

高稳定性的传感器是传感器设计追求的目标,其中温漂是影响设计传感器性能稳定性的主要因素。采用ARIMAGARCH模型对传感器温度的线性和非线性漂移进行了建模,找出温度漂移数据的变化规律。对于线性漂移,滞后1阶的样本自相关系数大于2倍标准差,说明该温漂序列具有短期相关性。对于非线性漂移,残差平方的自相关系数2阶截尾,偏自相关系数1阶截尾,说明具有ARCH效应。研究结果表明,在不影响信度的情况下,提出的模型能够更加精确的预测置信区间,表明长时间的高温实验对传感器稳定性造成的影响能够控制在合理范围内。     

风冷汽油机热载荷分析及喇叭型导流罩的影响研究

为了深入分析热载荷对风冷发动机运行稳定性的影响，通过CONVERGE仿真软件对某四冲程风冷式汽油发动机缸内燃烧过程进行数值模拟计算，获得了完整的缸内燃气侧热边界条件。基于FLUENT仿真软件，建立发动机热流固耦合稳态传热仿真模型，获得了燃气侧不均匀热载荷与机体外复杂空气流动共同作用下的发动机热载荷分布，并通过台架实验验证了稳态传热仿真的准确性。设计喇叭型结构导流罩，分析了导流罩收缩比对导流罩性能的影响，改善发动机的冷却效果。结果表明：发动机稳态传热仿真与台架测试最大误差为3.12%,仿真模型具有较高的准确性；发动机机体最高温度为655 K,出现在排气道端口处位置；随着导流罩收缩比的减小，发动机冷却散热性能增强，收缩比λ为1.94时，冷却强化效果最好，机体最高温度降低8.8 K。研究对风冷汽油机的冷却系统设计及优化具有一定的指导意义。     

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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