超声波清洗技术工艺研究

产品的装配试验状态与产品表面清洁度有直接关系,尤其对于高精密产品来说保证产品"洁净"是十分必要的。此次研究主要针对管路、复杂结构壳体及弹簧等部件的清洗情况进行对比研究,对超声波下产品表面洁净度进行细致的分析,以提高产品清洗质量。利用新购置超声波清洗机,通过开展超声波清洗技术达到完善工厂清洗技术能力,并满足工艺要求。     

超滤处理含油污水的臭氧清洗机理研究

通过对臭氧清洗工艺参数优化,确定了膜的清洗流速为3.5 m/s,臭氧投加质量浓度为4 mg/L,清洗时间为10 m in,清洗水的初始pH值为10.利用该工艺参数对原油污染超滤膜进行清洗,总体膜通量恢复率接近100%.对清洗后的超滤膜污染物GC-MS分析表明,臭氧使膜表面轻烃类污染物氧化为小分子有机酸或CO2和H2O,而难溶于水的重烃类污染物降解为易溶于水的极性物质.     

聚醚砜中空纤维超滤膜的化学清洗

以某电厂的超滤膜为研究对象,利用光学显微镜、扫描电镜(SEM)、EDX能谱仪、傅里叶红外光谱仪等表征仪器对污染后的膜形貌及膜污染物进行了表征分析.结果表明:超滤膜同时存在有机物污染和无机物污染,外表面主要为无机污染物,内表面主要为有机污染物.使用了HCl、NaOH、NaClO及乙二胺四乙酸(EDTA)等化学清洗剂对膜进行了化学清洗,发现经NaClO和EDTA清洗后,膜通量恢复较明显;并对NaClO和EDTA清洗体系的清洗温度和清洗时间进行优化.研究了NaClO和EDTA的组合清洗对膜通量恢复的影响.结果发现:NaClO和EDTA对膜清洗效果表现出协同作用,方案F清洗后能使膜通量恢复到最大值1 780 L/(m2·h).     

模拟管袋坝接缝管路的糙率率定试验方法

为了解决模拟管袋坝袋间接缝管路的糙率边界条件模拟和观察试验的矛盾,自行设计一套糙率率定的试验装置,主要包括供水设备、模拟管路和数据采集设备.针对该试验装置提出了相应的试验原理和试验方法,并验证该试验装置及试验方法是可行的.在此基础上进行了纱网糙率率定试验,选出适当糙率的纱网完成对管路边界条件的模拟,同时满足观察管路中砂体的运移状态的需要.     

短舱管路接头耐火试验数值仿真预测

防耐火性能是航空发动机零部件满足适航要求的基本指标之一,在短舱火区内输送可燃液体的管路是其中的关键考核部件。为预测短舱管路耐火试验结果,评价管路接头火焰耐受性能,提出了开展标准火焰燃烧仿真获取第三类边界条件,通过管路流热耦合换热获取传热稳定后的流体域及固体域温度场,作为热边界条件进行结构变形分析考察管路接头接触状态的数值分析方法。通过直管火焰冲击试验及管路接头耐火试验对相关结果进行了验证。结果表明：出口管路温度预测结果误差小于3%,管路接头泄漏预测结果与试验结果一致。     

基于ANSYS的某型飞机液压管路应力测试

为了优化液压管路应力测试,减少测点数量,提高测试准确度,提出在应力测试前用ANSYS对管路进行受力分析,试验后用试验数据进行模型修正。通过对管路进行三维建模,将模型导入ANSYS,分析管路振动时应力分布,根据受力情况确定传感器的安装位置。后将测得的数据修正模型参数,通过模型计算最大应力。通过ANSYS优化应力测试,减少了传感器布置的数量,提高了测试的准确度。     

圆形管道90°汇流口局部能量损失

进行汇流管路特别是管路较短或汇流节点较多的管路系统设计时,正确确定管道汇流口水流局部能量损失具有重要意义.为此,根据水动力学基本原理,在分析90°汇流口独特水流特性及能量耗散机理的基础上,提出了局部能量损失系数的综合表达式,并应用试验资料对该综合表达式进行了验证.研究结果表明,正确分析管道汇流口水流的局部能量损失机理,必须考虑汇入断面上支流沿下游主流方向的动量输入和主支流间相互掺混引起的附加摩擦阻力的影响.     

印制电路板蚀刻废水中重金属污染物分析

对印制电路板生产中表面酸洗去除铜箔表面氧化层和蚀刻后清洗过程中产生的清洗废水中的重金属污染物进行了分析。除总铜污染因子外,应关注总镍、总铬等第一类污染物,并分析计算了污染物浓度,提出了废水处理过程中应分质处理,确保达标排放。     

民用飞机高压空气管路系统累积压力分析方法

本文介绍了一种民用飞机高压空气管路内气体压力累积现象,介绍了区域累积压力的分析方法。民用飞机高压空气管路由高压空气导管和调节活门等组成。在飞机起飞,活门失效或飞行员操作等情况下,管路系统中的调节活门处于关闭状态。由于活门的内部泄露,高压空气在管路系统内部不断聚集,在系统内部不同区域,空气聚集后形成不同内部压力。这一由空气聚集导致的管路压力升高的现象,称为管路系统压力累积。本文针对某型飞机高压管路系统,对管路进行了累积压力水平分析。高压管路系统设计需要确定系统在正常工作过程中的空气工作压力和温度水平,进而确定高压导管和调节活门的验证压力和爆破压力,保证管路和活门在该水平的压力温度条件下不发生失效。确定管路系统累积压力,对高压管路系统的设计和系统控制设计有非常重要的作用。     

论电厂化学EDTA清洗工艺

本文主要论述电厂化学清洗工艺。其清洗范围主要为高压给水系统、锅炉受热面、启动分离器、储水箱及过热器减温水管路等其他辅助回路。对清洗中出现的炉水循环泵跳泵、药品配制和浓度不足、受热面加热不均及辅助管道清洗范围等问题进行了详细叙述和分析。     

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

正~~