基于PCI总线的GPS接收机设计

介绍了基于周边元件扩展接口(PCI)总线的全球定位系统(GPS)接收机, 该接收机通过PCI总线实现PC机对相关器的控制并得到导航信息. 该接收机和参考接收机的同步测量结果表明, 两个接收机对定位信息获取的误差趋势相同, 通过接收机的水平误差散点图和时间序列垂直误差分布图可见, 该测量系统较稳定, 可准确地反映定位点的位置信息.      

几何非线性连续体结构拓扑优化仿生方法

利用基于Wolff法则的仿生方法对几何非线性、线弹性连续体进行拓扑优化.该仿生方法中引入构造张量作为设计变量用于描述设计域内各点处材料微结构的几何特征及其宏观弹性本构.同时,引入参考应变区间并结合Wolff法则用于确定结构中某点处材料的更新方案.考查了结构最优拓扑的网格依赖性以及参考应变区间对结构的最优拓扑及材料分布的影响.数值算例表明,结构的最优拓扑无网格依赖性.几何非线性线弹性连续体结构的最优拓扑明显地依赖于参考应变区间的选取.如果参考应变区间长度为零且荷载为指定位移时,按同比例改变荷载及参考应变区间上确界,可得到相近的最优拓扑和材料的分布.     

Parametric variational solution of linear-quadratic optimal control problems with control inequality constraints

A parametric variational principle and the corresponding numerical algo- rithm are proposed to solve a linear-quadratic （LQ） optimal control problem with control inequality constraints. Based on the parametric variational principle, this control prob- lem is transformed into a set of Hamiltonian canonical equations coupled with the linear complementarity equations, which are solved by a linear complementarity solver in the discrete-time domain. The costate variable information is also evaluated by the proposed method. The parametric variational algorithm proposed in this paper is suitable for both time-invariant and time-varying systems. Two numerical examples are used to test the validity of the proposed method. The proposed algorithm is used to astrodynamics to solve a practical optimal control problem for rendezvousing spacecrafts with a finite low thrust. The numerical simulations show that the parametric variational algorithm is ef- fective for LQ optimal control problems with control inequality constraints.     

Heusler合金NiCoMnSn中的磁场驱动马氏体相变、超自旋玻璃和交换偏置

合成了一系列Ni_50-xCo_xMn₃₉Sn₁₁ (8≤x≤10) 样品, 并对它们的结构和磁性进行了研究. 发现随Co含量的增加, 样品的饱和磁化强度逐渐增强, 并在Ni₄₂Co₈Mn₃₉Sn₁₁中实现了磁场诱发马氏体相变. 另外, 在Co大于8.0的成分中探测到了超自旋玻璃, 并且观察到交换偏置现象. 证实了超自旋玻璃的马氏体相和铁磁奥氏体母相共存, 这也是产生交换偏置的原因.我们猜测超自旋玻璃的形成可能是来源于Mn-Mn团簇的存在, 这和之前报道的Mn₂Ni_1.6Sn_0.4 的结果相一致^[1]. 关键词： NiCoMnSn Heusler合金 超自旋玻璃 交换偏置     

紫外应力发光材料SrMgSi2O6：Ce的制备与光谱性质研究

采用固相烧结法制备了3种紫外应力发光材料SrMgSi₂O₆：Ce_0.005、SrMgSi₂O₆：Ce_0.005,Er_0.015和Sr₂MgSi₂O₇：Ce_0.005,Er_0.015。XRD测试结果表明：SrMgSi₂O₆与Sr₂MgSi₂O₇具有相同的结构,掺杂离子的加入没有改变相结构。3种样品的荧光发射光谱很类似,均在330~400 nm紫外波段有较宽的发射谱带。应力发光曲线的测试结果表明,样品的应力发光强度与物体受力变化呈良好的对应关系,证明所制备的样品可以用来检测物体的受力情况。同时,研究了共掺杂离子以及改变基质结构对应力发光强度的影响,结果表明发光体中陷阱数目的增加以及基质对称性的降低有利于应力发光的产生。由于所开发的样品波长在紫外区,因而可以作为光源来激发其他颜色的光致发光材料从而实现多颜色应力发光材料的开发。     

纳米发光粉体YVO4：Sm的研制及性能

用明胶作为络合剂，以乙二醇作为分散剂，采用络合溶胶-凝胶法，合成了纳米级的YVO4：Sm发光粉体．并进行了荧光光谱(FR)、X-射线衍射(XRD)和透射电镜(TEM)等一系列表征．结果表明，制备的粉体粒子尺寸在20nm左右，因此，用明胶作络合剂的溶胶-凝胶法是一种很好的合成纳米粉体的方法．此外，将该纳米粉体与自制的相应YVO4：Sm块体对比，发现纳米发光材料的发光强度较块体发光粉体的强度有一定明显的增强。     

NON-INTERIOR SMOOTHING ALGORITHM FOR FRICTIONAL CONTACT PROBLEMS

A new algorithm for solving the three-dimensional elastic contact problem with friction is presented. The algorithm is a non-interior smoothing algorithm based on an NCP-function. The parametric variational principle and parametric quadratic programming method were applied to the analysis of three-dimensional frictional contact problem. The solution of the contact problem was finally reduced to a linear complementarity problem, which was reformulated as a system of nonsmooth equations via an NCP-function. A smoothing approximation to the nonsmooth equations was given by the aggregate function. A Newton method was used to solve the resulting smoothing nonlinear equations. The algorithm presented is easy to understand and implement. The reliability and efficiency of this algorithm are demonstrated both by the numerical experiments of LCP in mathematical way and the examples of contact problems in mechanics.     

结构分析有限元程序JIGFEX和它的新发展

本文简要介绍了结构静，动力有限元分析程序ＪＩＧＦＥＸ的主要特色和它在土与结构相互作用，饱和土分析，动态子结构分析，非线性接触分析，高层建筑抗震分析，温度场与热传导分析，群论结构分析以及平稳与非稳多点随机地震激励响应分析等多方面最新发展。     

土体固结分析的一种有效算法

对土体固结分析,提出一种有效算法,避免了文[1]求解的迭代过程。文末附有算例。     

INSTABILITY AND DISPERSIVITY OF WAVE PROPAGATION ININELASTIC SATURATED/UNSATURATED POROUS MEDIA

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