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°.     

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.     

Evaluation of ultimate bearing capacity of Y-shaped vibro-pile

Based on Mindlin stress solution, a numerical computational method was proposed to calculate the stresses in the ground induced by side friction and the resistance of Y-shaped vibro-pile. The improved Terzaghi’s and ЪерезанцевВГ’s methods for ultimate bearing capacity evaluation were proposed by considering the stress strength induced by friction resistance at pile head level of Y-pile. A new method to calculate the ultimate bearing capacity of Y-pile was also proposed based on the assumptions of soil failure mode at the tip of Y-pile and the use of Mohr-Coulomb soil yield criterion and Vesic compressive correction coefficient with the induced stresses in the ground. Based on the comparisons with the field static load test results, it is found that the improved Terzaghi’s method gives higher ultimate capacity, while the other two methods shows good agreement with the field results.     

Adhesion coefficient of automobile tire and road surface

The adhesion coefficient of automobile tire and road surface was analyzed and the formula about it was derived.Some suggestions about highway construction,driving safety of the drivers and the judgment of the traffic accidents were presented.The results show that the adhesion coefficient is a function with the extreme value.If there is atmospheric pressure in the tire,the load of the vehicle and the degree of the coarse on the road surface is not selected properly,it will reach the least and affect the safety of the running automobile.     

Effects of stress conditions on rheological properties of granular soil in large triaxial rheology laboratory tests

In order to study the rheological properties of red stone granular soil,a series of rheological experiments were executed on large tri-axial rheological apparatus.Under 100,200 and 300 kPa confining stress conditions,the rheological tests were carried out.These experiment results showed that the stress conditions,especially the stress level were the critical influencing factors of the rheological deformation properties.Under the low stress level(S=0.1),the granular soil showed the elastic properties,and there was no obvious rheological deformation.Under the middle stress level(0.20.8) creep curves showed the non-linear viscous plastic rheological properties.Especially,under the stress level of S=1.0,the accelerated rheological phase of creep curves occurred at early time with a trend of failure.The stress level had obvious effects on the final rheological deformation of the soil sample,and the final rheological deformation increments nonlinearly increased with stress level.The final rheological deformation increment and step was little under low stress level,while it became large under high stress level,which showed the nonlinearly rheological properties of the granular soil.The confining pressure also had direct effects on final rheological deformation,and the final rheological deformation linearly increased with confining pressure increments.     

2008年我国房地产业的发展模式与市场把握

在深入市场调查、认真采集数据和科学分析研究的基础上,从我国新一年房地产业发展的"背景和环境"、"预期和责任"、"风险和影响"、"保障和创新"等方面进行阐述和论证.     

窃取商业秘密获得的专利权归商业秘密权利人所有——兼谈商业秘密构成要件和范围

中国加入WTO以后,知识产权的保护意识日益强化,作为知识产权范畴的专利权更是被人们普遍关注和重视.以"错案"为研究对象,运用商业秘密的有关理论以及保护商业秘密和专利权的有关法律制度,特别是从窃取商业秘密获得的专利权归谁所有的角度,对人民法院的判决进行了分析研究,指出了人民法院的判决是错误的,提出了窃取商业秘密获得的专利权归商业秘密权利人所有.这有利于人民法院公正司法,依法审判.     

从语气助词的角度浅析日语表达方式的特性

日语中有着十分丰富的语气助词,其虽然不具有实际的意义,然而通过语气助词,却能够流露出说话者的心情和感受,传递出不溢于言表的隐性含义,在日常的表达中扮演着十分重要的角色.从语气助词的角度,分析总结日语在表达上所具有的特性.     

Additional water use influencing strength and fluidity of recycled concrete

Through adding different additional water use,the compressive strength,splitting tensile strength and fluidity of recycled concrete of three aggregate combination forms were studied by experiment respectively.The experimental results show that with the increase of adding additional water use,the compressive strength and splitting tensile strength of recycled coarse aggregate concrete decrease,but that of recycled fine aggregate concrete and recycled all aggregate concrete increase firstly then decrease.When additional water use is added more 15% or 20% than that of basic ordinary concrete,the recycled coarse aggregate concrete and fine one can get pretty good fluidity.When it is added more 30%,the recycled all aggregate concrete has fluidity that is just satisfied.     

情趣与意象的契合——《逢雪宿芙蓉山主人》与《雪夜林边驻脚》之比较

通过分析《逢雪宿芙蓉山主人》与《雪夜林边驻脚》两诗的情趣和意象,发现两诗都采用了大致相似的意象.但由于诗人各自的文化传统的差异,在两诗中所传达的情趣却不同.然而,正是由于两诗各自在情趣与意象上的契合,才创造出了各自完美的诗境.     

Processing the rig test data of an air filling twin-tube shock absorber

A separation method is proposed to design and improve shock absorber according to the characteristics of each force. The method is validated by rig test. The force data measured during rig test is the resultant force of damping force, rebound force produced by pressed air, and friction force. Different characters of damping force, air rebound force and friction force can be applied to seperate each force from others. A massive produced air filling shock absorber is adopted for the validation. The statistic test is used to get the displacement-force curves. The data are used as the input of separation calculation. Then the tests are carried out again to obtain the force data without air rebound force. The force without air rebound is compared to the data derived from the former tests with the separation method. The result shows that this method can separate the damping force and the air elastic force.     

Research on the Earth system multi-body force system dynamical model

This paper presents an overview of the binding force and freedom force of Earth system, and describes force moment to point and line and force system in the Earth system. It introduces the force theory of the Earth system multi-body force system from special or equivalent force system of Earth system mechanics, general force and no-power force of Earth system. Finally it describes the force and moment of nodes of Earth system and provides basic model for the research of the Earth system multi-body dynamics.     

介观与宏观角度下的磨削力修正研究

从砂轮磨粒的几何形状和砂轮地貌入手,针对45^# 钢磨削力变化规律,从介观和宏观两个角度对磨削力进行了研究。通过介观角度下的磨削力仿真分析,研究了磨削深度、磨削速度与磨削力之间的关系;通过宏观角度下的磨削力仿真研究,得出了某一磨削参数下的磨削应力云图和磨削力变化图;对介观和宏观角度下的磨削力研究结果进行总结,得到了45# 钢磨削力的修正公式。从仿真研究以及得到的磨削力修正公式可以看出,磨削力随磨削深度的增大而增大,磨削深度越大,磨削力变化趋势越明显;磨削力随磨削速度的增大而减小,当磨削速度超过一定值时,磨削力减小趋势减缓。     

空调风管中细颗粒物受力机理研究

对空调风管中的细颗粒物主要受力类型进行了梳理,发现主要作用力都与颗粒粒径相关,理论计算结果表明,曳力是湍流流场中细颗粒物的主要作用力,剪切升力和热泳力是近壁面区颗粒的重要作用力,高压静电场下细颗粒所受电场力成为主要作用力,库仑力和偶极子力在颗粒距离极近时发挥作用.     

高强螺栓群纯弯作用下中和轴位置研究

从分析存在于端板及高强螺栓中的轴增力、压减力及荷载外拉力的概念及三者间关系入手,指出目前高强螺栓计算中关于中和轴位置及荷载外拉力分布的假定所存在的问题.建立了两种关于螺栓的轴增力和压减力关系的力学模型,此两种模型所得到的荷载外拉力均为对距离的非线性分布.基于其中一种模型,应用力学平衡原理,推导出了高强螺栓关于中和轴位置的方程组,进而对方程组进行求解得到高强螺栓群在弯矩作用下的中和轴位置,为高强螺栓的工程设计提供了一定的理论参考.     

波形刃铣刀片受力密度函数的研究

为建立铣刀片瞬态铣削力模型，进行了铣削力试验，对铣削力数据进行了采集，并对铣削力的试验数据进行了分析及数据拟合；建立瞬态铣削力数学模型及铣削力受力密度函数，同时对受力密度函数曲线及曲面进行了模拟，为波形刃铣刀片的应力场分析及评价提供理论依据．     

遥操作机器人执行末端的力反射型变增益力反馈算法

在以遥操作工程机器人执行末端为从端的力反馈双向伺服系统中,为了使主端受力真实地反映从端执行末端叉手所受的环境力,在力反射型算法的基础上,提出了一种变增益力反馈算法。根据机器人叉手的运动模型建立叉手液压缸位移与驱动力关系的数学模型,以此调节主端的力反馈控制增益。为了验证该算法的优越性,将该算法与常用的力反射型算法进行了比较实验。实验证明,该算法在保证系统稳定性的前提下,精确地反映了机器人叉手在运动中的惯性力和阻尼力所带来的影响,操作者可以更为真实地感知机器人从手所受环境力的变化,有利于系统工作性能的提高。     

Study of the interfacial interactions in the molybdenite floatation system

Interfacial interactions involving Van der Waals force, hydrophobic attractive force and hydration exclusive force were investigated in this paper. The interfacial interactive free energy of a series of interfaces occurring between minerals, water, collectors and bubble was calculated. The results show that a Van der Waals attractive force and a hydrophobic attractive force exist between each mineral and water interface. The hydrophobic attractive force between molybdenite and water is markedly weaker than the hydrophobic attractive force between gangue and water. The hydrophobic attractive force between collector molecules and water is the main driving force that causes the collectors to become dispersed in the pulp. The strong hydrophobic attractive force between molybdenite and the bubble interface is the basic reason for the natural floatability of molybdenite. The Van der Waals force between molybdenite and the collectors is attractive in water solution, but it is not the cause of the main force between them. The main force that results in the collection effect is a hydrophobic attractive force caused by the Lewis acid-base interaction at the molybdenite surface. A floatation experiment shows that the adsorption intensity of the collector on the molybdenite surface is not the crucial factor for molybdenite floatation. Rather, the dispersing capability of the collector in the water phase and its selectivity for the various minerals in the floatation system are more important.     

六维力传感器标定及其在气动柔性手指上应用

提出了一种精密六维力传感器的标定方法。搭建了实验平台,采用移动滑台搭载测力计对传感器施加外力的方式,得到传感器在不同外力情况下各方向力和力矩输出的电压差值,利用数值分析方法对电压差值和外力、力矩大小之间的关系进行分析,获得了电压差值与外力、力矩大小的关系方程,并应用六维力传感器对气动柔性手指进行了夹持力实验研究。实验结果表明,柔性手指指尖夹持力、所受力矩随气压增加而增大,且指根处受力、力矩均小于指尖夹持力及夹持力所产生力矩,为后续柔性机械手的研究提供了科学依据。     

考虑侧向约束的预应力混凝土超静定结构次内力计算及影响

由于侧向约束对超静定结构中预压力的传递以及二次内力产生的影响,有侧向约束的框架梁或连续刚构桥的预应力次内力计算比无侧向约束的连续梁次内力计算更为复杂.文中提出一种计算思路,把预加力分解为侧向约束引起的作用在柱上的预压力损失及作用在梁上有效预压力,结合等效弹簧模型及简化结构计算侧向约束预压力损失引起的次内力,利用约束次弯矩法计算有效预压力引起的次内力,然后进行叠加计算总次内力影响.通过实例分析了有侧向约束对框架结构二次内力的影响.结果表明,该影响随着梁柱刚度比减小而增大,忽略侧向约束预压力损失引起的附加二次内力影响是不合理也不安全的,文中方法能够满足工程实际中的精度要求,有助于预应力框架结构的设计和内力分析.