确定柔性机器人主动控制力的一种新算法

提出一种计算柔性机器人铰上主动控制力的程式化方法，在已知柔性机器人铰上运动学规律的前提下求产生这种规律的主劝控制规律通常需先通过求解系统动力学正总是俐到部件变形规律，然后通过动力学逆问题得到。本文在不破坏原方程程式化的形式的前提下将原动力学方程转化为另一种等价的程式化形式将上述两个过程合并在一起求解，减化了计算步骤，并提高了计算效率。     

框架剪力墙结构考虑剪力墙剪切变形时的内力和位移

本文用沿高度方向连续化的方法，建立了考虑剪力墙剪切变形时框架剪力墙结构在水平荷载作用下共同工作时的平衡微分方程。推导了多种荷载情况下结构内力和位移的计算公式。同时，进一步分析了剪切变形对框架剪力墙结构内力和位移的影响。     

企业经济效益量化分析与控制技术

针对目前国有企业存在的问题，在理论上对经济系统的机理和机理与效益之间的关系进行了深入分析，从生产力与生产关系的深层次上指出了国有企业经济效益下降的原因，并从技术上提出了政府对国有企业调控职能的实现方法。     

On the numerical implementation of variational arbitrary Lagrangian–Eulerian (VALE) formulations

This paper is concerned with the implementation of variational arbitrary Lagrangian–Eulerian formulations, also known as variational r‐adaption methods. These methods seek to minimize the energy function with respect to the finite‐element mesh over the reference configuration of the body. We propose a solution strategy based on a viscous regularization of the configurational forces. This procedure eliminates the ill‐posedness of the problem without changing its solutions, i.e. the minimizers of the regularized problems are also minimizers of the original functional. We also develop strategies for optimizing the triangulation, or mesh connectivity, and for allowing nodes to migrate in and out of the boundary of the domain. Selected numerical examples demonstrate the robustness of the solution procedures and their ability to produce highly anisotropic mesh refinement in regions of high energy density. Copyright © 2006 John Wiley & Sons, Ltd.     

对称性分子间氢键诱导液晶

本文以４－［（４－烷氧基苯甲酰氧基）－４’－苯乙烯基］－吡啶（７ＳＺ和１０ＳＺ）为质子受体．以脂肪族二元羧酸（ｍＤＡ）为质子给体，合成了对称性的氢键复和物。其液晶行为经ＤＳＣ和偏光显微镜研究，结果表明复合物的液晶范围较相应的质子受体的液晶范围宽．     

建设国家稳定社会武警水电部队的双重职能与使命

自上世纪60年代以来,武警水电部队肩负“劳武结合、能工能战”的双重使命,承建或参建了大中型水电站30多座,装机容量300多万kW。从红水河畔到青藏高原,从三峡工地到西电东送骨干工程,到处都留下了武警水电部队的丰功伟绩;部队同时承担了维护社会稳定、处置突发事件和重大抢险救灾等光荣任务。为适应水电部队的新定位,部队坚持科学发展观,加强人才队伍建设;坚持科技强军思想,加强装备和信息化建设;依法上勤,科学组训,努力提高管理水平,不断拓展施工领域和市场空间,誓为国家作出新的更大的贡献。     

On probability distributions of contact force magnitudes in loaded dense granular media

This paper discusses possible models for probability distributions of contact force magnitudes in loaded granular media. Many authors have studied such distributions, based on experiments with real particles as well as simulations in 2D and 3D. This has led to various and partly contradicting suggestions for the form of those distributions, which are described in the present paper. Its new theoretical investigations start from the empirically justified assumption that the components of contact forces follow exponential distributions with a certain dependence structure. This leads to distributions of force magnitudes similar to Gamma distributions with shape parameters depending on space dimension, which is in good agreement to results from experiments and numerical simulations. Also the analytical and statistical difficulties of the problem of determination of distributions of force magnitudes are discussed.In a discussion of Stefan Luding and D.S. the idea arose to consider dependent force components. Niels Kruyt supported our work by sending his papers and by patient discussions via e-mail and a careful reading of an earlier version of this paper.We had a very useful discussion with Farhang Radjai about the problem P(0)=0 and experiments with real disks. Finally, we are grateful to Tomaso Aste for leading our attention to infinitely divisible distributions.     

Thermodynamic Properties of Sulfur Hexafluoride

We present new vapor phase speed-of-sound data u(P, T), new Burnett density–pressure–temperature data (P, T), and a few vapor pressure measurements for sulfur hexafluoride (SF₆). The speed-of-sound data spanned the temperature range 230 KT460 K and reached maximum pressures that were the lesser of 1.5 MPa or 80% of the vapor pressure of SF₆. The Burnett (P, T) data were obtained on isochores spanning the density range 137 mol·m^–34380 mol·m^–3 and the temperature range 283 KT393 K. (The corresponding pressure range is 0.3 MPaP9.0 MPa.) The u(P, T) data below 1.5 MPa were correlated using a model hard-core, Lennard–Jones intermolecular potential for the second and third virial coefficients and a polynomial for the perfect gas heat capacity. The resulting equation of state has very high accuracy at low densities; it is useful for calibrating mass flow controllers and may be extrapolated to 1000 K. The new u(P, T) data and the new (P, T) data were simultaneously correlated with a virial equation of state containing four terms with the temperature dependences of model square-well potentials. This correlation extends nearly to the critical density and may help resolve contradictions among data sets from the literature.     

Discontinuous Bifurcation Analysis of a Coupled Rate-Dependent Damage and Plasticity Model for Impact Responses

To identify the transition from continuous to discontinuous modes in the failure evolution of quasibrittle materials under impact, a coupled rate-dependent damage and plasticity model is developed within the thermodynamics framework. Due to the simplicity in model formulation, a continuum tangent stiffness tensor could be obtained for discontinuous bifurcation analysis, and the model parameters could be calibrated from split Hopkins pressure bar experimental data available. The coupled rate-dependent model could describe not only the pressure-dependent hardening/softening response but also the degradation of material stiffness under impact. A geometric criterion with a corresponding solution scheme is presented to explore the rate-dependent transition from continuous to discontinuous failure modes in the Mohr coordinates. The uniaxial compressive loading path is considered to illustrate the loading rate effect on the critical localization orientation and hardening parameters. It appears from the preliminary results that the coupled rate-dependent local continuum model might be combined with a decohesion model via discontinuous bifurcation analysis so that large-scale simulation of failure evolution could be performed without invoking higher-order spatial terms in the stress-strain space.     

Material forces for inelastic models at large strains: application to fracture mechanics

Elastomeric materials show a wide range of different elastic and inelastic properties. Additionally, this class of materials is subjected to large deformations. Considering all these effects, fracture mechanical investigations are very challenging tasks and cannot be performed with standard approaches. Effects of inhomogeneities and discontinuities such as cracks can be investigated with the so-called material force approach in an efficient and elegant way. For comprehensive investigations of inelastic materials, the complete balance of the material motion problem has to be formulated. In this case, the material volume forces depend on the internal history variables which are required for the inelastic constitutive model. This paper derives a general formulation for rate-dependent and rate-independent inelastic materials based on a multiplicative split of the deformation gradient to cover viscoelastic and elastoplastic materials at finite deformations.