Intact soft clay’s critical response to dynamic stress paths on different combinations of principal stress orientation

Comprehensive tests on Hangzhou intact soft clay were performed, which were used to obtain the soils’ critical response to undrained dynamic stress paths under different combinations of principal stress orientation. The different combinations included cyclic principal stress rotation (CPSR for short), cyclic shear with abrupt change of principal stress orientation (CAPSO for short) and cyclic shear with fixed principal stress orientation (CFPSO for short). On one side, under all these stress paths, samples have obvious strain inflection points and shear bands, and the excess pore water pressure is far from the level of initial effective confining pressure at failure. Stress paths of major principal stress orientation (α) alternating from negative and positive have quite different influence on soil’s properties with those in which α is kept negative or positive. On the other side, due to the soil’s strongly initial anisotropy, samples under double-amplitudes CPSR and CAPSO (or single-amplitude CPSR and CFPSO) have similar properties on dynamic shear strength and pore water pressure development tendency when α is kept within ±45°, while have quite different properties when α oversteps ±45°.     

Research advances of un-symmetric constitutive theory of anisotropic viscoelastic liquids and its hydrodynamic behavior

Research advances of un-symmetric constitutive equation of anisotropic fluid,influence of un-symmetric stress tensor on material functions,vibrational shear flow of the fluid with small amplitudes and rheology of anisotropic suspension were reported.A new concept of simple anisotropic fluid was introduced.On the basis of anisotropic principle,the simple fluid stress behaviour was described by velocity gradient tensor F and spin tensor W instead of velocity gradient tensor D in the classic Leslie-Ericksen continuum theory.Two relaxation times analyzing rheological nature of the fluid and using tensor analysis a general form of the constitutive equation of co-rotational type was introduced.More general model LCP-H for the fluid was developed.The unsymmetry of the shear stress was predicted by the present continuum theory for anisotropic viscoelastic fluid-LC polymer liquids.The influence of the relaxation times on material functions was specially studied.It is important to study the unsteady vibrational rotating flow with small amplitudes,as it is a best way to obtain knowledge of elasticity of the LC polymer,i.e.dynamic viscoelasticity.For the shear-unsymmetric stresses,two shear stresses were obtained thus two complex viscosities and two complex shear modulus(i.e.first and second one) were introduced by the constitutive equation which was defined by rotating shear rate introduced by author.For the two stability problems of fluid,such as stability of hydrodynamic flow and orientational motion,were discussed.The results show that the polymer suspension systems exhibit anisotropic character.The PNC systems can exhibit significant shear-thinning effects.For more concentrated polymer nano-suspensions,the first normal stress difference change from positive to negative,which is similar to LC polymer behavior.     

当前民办高校融资难的成因及对策

针对民办高校所需办学经费无国家财政拨款,全部为自筹资金的现状,分析了形成当前民办高校融资难的原因,既有信贷政策、银行方面的因素,也有民办高校自身的因素.提出民办高校要生存,要发展,光靠举办者投入或捐赠以及每年的学费收入是不够的,还需要积极拓展更多融资渠道解决办校融资难的问题.     

脉冲振动预磁器的研究和设计

根据细粒磁性物回收工艺中需要使用预磁器的要求,研究预磁器的工作时序、充放电回路的电器元件特性和电路电压、电流特征.设计的电磁预磁器磁场强度高,能耗低,性价比高.对预磁化电路展开理论计算和推导.首次提出脉冲振动预磁器系统结构,将RLC电路振荡波形转变为振动波形,形成"脉振"高场强,延长了线圈的使用寿命.经实际运行检验,该装置性能稳定,效果好,能耗低,每小时耗电仅0.8 kW,在预磁器领域是一项创新的实用技术.     

城市污水热能资源化的基础研究

作为城市污水热能资源化的基础研究,根据理论分析方法,对有效利用城市污水所赋存的热能时,其节能效果和对减轻大气污染的作用进行了若干分析和探讨.分别计算了流量为1 m3/s时城市污水赋存的热量,以及采暖面积为1万m2时所需的城市污水及赋存的热量,与空调、锅炉相比产生相同热量时的一次能和二次能的消减量,以及相应条件下的污染物年间(采暖期)消减量等.     

解读连战先生的民族情

文章试图从两方面解读连战先生深厚的民族情.这种民族情一方面来源于他的家族,连战的先祖到台湾死也不臣服清,曾祖父至父亲三代以各种形式坚持抗日及父母对他言传身教;另一方面与他早年在祖国大陆的生活经历有关,从他对抗战和日本的态度及祖国大陆寻踪等方面体现出来.     

Vibrational shear flow of anisotropic viscoelastic fluid with small amplitudes

Using the constitutive equation of co-rotational derivative type for anisotropic viscoelastic fluid-liquid crystalline(LC),polymer liquids was developed.Two relaxation times are introduced in the equation:λn represents relaxation of the normal-symmetric stress components;λs represents relaxation of the shear-unsymmetric stress components.A vibrational rotating flow in gap between cylinders with small amplitudes is studied for the anisotropic viscoelastic fluid-liquid crystalline polymer.The time-dependent constitutive equation are linearized with respect to parameter of small amplitude.For the normal-symmetric part of stress tensor analytical expression of the shear stress is obtained by the constitutive equation.The complex viscosity,complex shear modulus,dynamic and imaginary viscosities,storage modulus and loss modulus are obtained for the normal-symmetric stress case which are defined by the common shear rate.For the shear-unsymmetric stress part,two shear stresses are obtained thus two complex viscosities and two complex shear modulus(i.e.first and second one) are given by the constitutive equation which are defined by rotating shear rate introduced by author.The dynamic and imaginary viscosities,storage modulus and loss modulus are given for each complex viscosities and complex shear modulus.Using the constituive equation the rotating flow with small amplitudes in gap between two coaxial cylinders is studied.     

玉米中转基因成分的定性PCR检测

利用改良 CTAB 法提取玉米产品的基因组 DNA,应用 PCR 检测方法,并以玉米特异性内源基因 IVR 为内参,花椰菜花叶病毒 35S 启动子(CaMV35S 启动子)、农杆茵胭脂碱合成酶终止子(NOS终止子)为靶基因检测玉米中是否存在转基因成分.实验结果表明,有些玉米样品中存在转基因成分,表明市场上存在未经标识的转基因玉米及其加工品.     

利用双折射晶体实现双偏振光叠加的教学研究

利用晶体的双折射现象和它的基本性质,采用现代光纤和CCD摄像放大技术手段研究了双偏振光的叠加和干涉现象,讨论了学生在教学中不易理解的难点问题.     

科技期刊版式设计略谈

对科技期刊版式设计中的标题、插图与空白的处置进行了分析探讨,认为科技期刊版式设计在总体上应是追求格式一致与节奏变化的统一,整体性与连贯性的统一.布局合理的版式设计带给期刊的是整体的和谐美,别具风格的版式设计标志着期刊的个性特征.     

时域指标在除尘风机轴承故障诊断中的应用

避免突发性设备事故造成的损失,设备故障诊断方法是非常有效的手段。本文着重介绍时域指标在转炉除尘风机滑动轴承故障诊断中的应用。     

单片机实践教学的问题与对策

实践教学是整个教学过程中的重要环节,然而许多学校教学中,单片机实践教学的方法、手段远远不能满足实际需要,并已成为单片机难教、难学的根源所在。文章从教学资源、教学演示、教学装置、教学实用性等诸方面对单片机课程的实践教学进行了比较深入的剖析,并提出了一些新的对策。     

某商住楼变压器容量的选择

主要分析了在正常情况、火灾情况,以及非火灾事故3种状态下,商住楼变压器的负荷计算,以便确定变压器容量．     

微机母线保护在开关站的应用及分析

LFP—975专用母线保护采用了以差电流为总起动元件 ,以母联电流方向或两母线间序电压差值 (方向·幅值 )作为故障母线选择元件的工作原理。本文在保护装置运行的基础上 ,对母线短路时以序电压比较作为故障母线选择元件的灵敏度进行了分析 ,同时通过计算提出了参数修改方法     

林东水库大坝渗流分析

根据渗流观测资料分析和有限单元法反演计算 ,分析了林东水库长期出现的坝脚渗水及坝坡渗漏的原因 ,建议对坝基与坝体进行防渗处理     

建筑消防设施火灾隐患的分析与对策

通过工程实例对当前建筑消防设施存在的火灾隐患进行了深入细致分析,并提出了相应的对策。     

试论模糊理论在变压器故障诊断专家系统研制中的应用

不确定问题是建立变压器故障诊断系统中一个难点。本文从不确定知识的获取，不确定知识的表示和不确定推理三个方面，利用模糊理论进行研究分析，并提出解决问题的对策。     

钱塘江流域水厂取水口管道延伸施工方法的探讨

采用新的围堰施工方法,在进行水下管道与取水口沉井连接时,能避免因施工而影响水厂供水,避免了因停水而造成生产重大损失和居民生活用水不便,此施工方法有一定的推广意义.     

堤坝地形对直流视电阻率曲线影响的实验研究

直流电阻率法是一种无损检测方法，因其快速、经济、直观、高效率而常用于堤坝隐患探测中，其基本理论是建立在半无限空间基础上的，然而堤坝作为一类较为特殊的几何体，会影响地下电场的空间分布规律，因此堤坝的这种特殊几何形状会对视电阻率造成一定的影响，从而给测量结果的正确解释带来不利影响。通过对几类简单堤坝隐患模型实验的结果进行分析可知，在堤坝上进行直流电阻率法工作必须进行地形改正，才有可能对测量结果做出正确的解释，最后简要介绍了地形改正的方法。     

我国粮食安全现状及其保障制度的完善

中国是世界上人口最多的国家,粮食安全始终是中国经济社会发展中的首要战略问题之一.近年来,国际粮食市场趋紧,有的国家和地区还出现较为严重的短缺;而在中国,受耕地面积减少、农民种粮意愿下降等诸多因素制约,在相当一段时间里,粮食形势仍处于"紧平衡"状态.文中通过对我国粮食安全理论和现状的阐述,提升对新形势下粮食安全的认识,分...