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1.
研究常曲率的3维球面S3到复射影空间CP4中的等变极小浸入,研究结果表明这种浸入只能是弱Lagrangian浸入,从而是全测地的。  相似文献   

2.
研究复射影空间CP4中常曲率的等变极小3维球面S3=SU(2),结果表明这种浸入若不是弱Lagrangian浸入,则其截面曲率C≤1。  相似文献   

3.
邯钢连铸板坯结晶器内流场的水模拟研究   总被引:1,自引:0,他引:1  
用水力学模拟实验方法研究邯郸钢厂板坯结晶器内流场,分析在确定的拉速参数下浸入式水口结构尺寸对连铸结晶器内钢液流动状况的影响,并优化出适合邯郸钢厂板坯连铸工艺的浸入式水口结构尺寸。  相似文献   

4.
以某钢厂210 t RH装置为研究对象,利用水力模型对现场生产过程进行物理模拟,研究驱动气体流量、顶吹气体流量、枪位、浸入深度和真空度对脱碳速率的影响.结果表明,随顶吹气体流量的增大,脱碳速率明显增大;随插入管浸入深度的增大,脱碳速率略有增大;随真空度的增大、枪位的减小,脱碳速率逐渐增大;驱动气体流量对脱碳速率的影响很小.真空度为3 616 Pa、枪位为40 mm、插入管浸入深度为125 mm、驱动气体流量为4.0 m3/h和顶吹气体流量为4.8 m3/h时,脱碳速率最大.  相似文献   

5.
RH精炼过程循环流量及夹杂去除的水模型研究   总被引:1,自引:1,他引:0       下载免费PDF全文
以某钢厂120tRH真空精炼炉为原型建立水模型,研究不同工艺参数对RH精炼过程钢液循环流量和夹杂去除率的影响。结果表明,钢液循环流量随着驱动气体流量、浸入深度、真空度、气孔数的增大而增大,随处理量的增大而减小,实验室循环流量最佳工艺参数为:气体流量2.8m3/h,浸入深度150mm,真空度3614Pa,气孔数12个;夹杂去除率随驱动气体流量、浸入深度、真空度和气孔数的变化均不是单调的,而是存在一个最佳值使夹杂去除率最高,实验室去除夹杂的合理工艺条件为:气体流量2.2m3/h,浸入深度125mm,真空度为3500Pa,气孔数8个。  相似文献   

6.
设M是紧的定向曲面,χ:M→CP。是常Kǎhler角的浸入,给出了χ是正自旋扭曲全纯浸入的充要条件和负自旋扭曲全纯浸入的必要条件.  相似文献   

7.
连铸结晶器液面波动的模拟   总被引:8,自引:0,他引:8  
基于Fr-We相似特征数,通过相似比例为0.6的水模型实验,系统地研究了拉速、浸入深度、吹气量、水口直径和侧孔倾角对结晶器液面波动的影响。结果表明:结晶器液面波动是由于气泡的逸出,流股对液面的直接冲击和驻波综合作用造成的;结晶器液面波随吹气量的增加而增加而增大,拉速、浸入式水口的浸入深度、直径及侧孔倾角对液面波动的影响具有双重性。  相似文献   

8.
以新型流化床颗粒层过滤器为应用对象,对内置过滤元件的流化床料层阻力进行了实验研究,实验发现,在没有床料循环时,过滤元件浸入料层的有效面积越大,料层阻力下降越多,通过定义元件浸入料层有效面积与床截面之比的无因次数,回归得到了内置过滤元件流化床料层阻力的经验表达式,为过滤器的进一步研究奠定了基础。  相似文献   

9.
赵晓姣 《科技资讯》2013,(18):180-180
本文论述了安全工程专业英语教学中存在的不足,浸入式英语教学法的概述及原则,提出了浸入式教学法在安全工程专业英语教学过程中的蛊用对策。  相似文献   

10.
蔡咏梅 《科技信息》2009,(28):I0135-I0136
我国现行的“双语教学”实际上是外语浸入式教学,主要采用的是英语半浸入式教学模式。英语浸入式教学必须明确教学的目标,注重培养既掌握专业知识又掌握外语的高素质、复合型人才。本文结合我院计算机专业双语教学的实践,研究分析影响英语浸入式双语教学过程的关键因素,以更好地推动双语教学的发展。  相似文献   

11.
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.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

13.
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。  相似文献   

14.
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.  相似文献   

15.
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-  相似文献   

16.
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-  相似文献   

17.
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  相似文献   

18.
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  相似文献   

19.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

20.
<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  相似文献   

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