非线性变形对大范围平面运动梁动力学特性的影响

根据柔性梁的几何非线性变形理论,从连续介质的力学原理出发,针对大范围运动的平面柔性梁,考虑了弯曲的非线性因素对横向变形的影响,得到了较为精确的变形模式。利用Lagrange方程建立了非线性变形模式下的动力学方程。仿真算例说明横向变形的非线性因素会对柔性梁的变形位移产生影响。     

基于虚拟仪器技术的装载机力学性能检测系统

虚拟仪器技术是测试与控制领域中最流行的技术之一。提出了一套基于虚拟仪器的装载机力学性能检测系统的开发方案。整套系统在LabWindows/CVI环境下开发,集成了DAQ采集、数据库及多媒体技术,实现了在线数据高速实时采集、信号分析、数据库管理等多项功能。目前整套系统已在几大工程机械厂投入使用,具有工程实际使用价值,可满足工程机械厂测试力学性能的任务多样化的要求。     

基于分项调查法和SWAT模型的水资源评价方法

现状下垫面条件下长系列天然径流资料是水资源评价的基础,但下垫面变化以及人类活动常常改变了水文循环过程,给水资源评价带来系统性偏差与较大的不确定性。以浠水流域为实例,提出将分项调查法和SWAT模型相结合的水资源评价方法,即根据水文站与水库位置关系建立不同水量平衡方程进行径流还原,利用与现状下垫面条件相近年份的还原后的径流数据进行参数率定与验证,并将构建的模型应用于长系列天然径流过程模拟计算。结果表明：仅采用分项调查法还原后的水文站降水-径流关系的一致性存在明显偏差;而通过构建基于现状下垫面条件下的SWAT模型,各水文站径流模拟值的降水-径流相关性优于还原值,且不同时期降水-径流关系一致性得到显著改善,表明该方法能够有效修正下垫面变化对径流的影响,有助于进一步开展水资源规划、水旱灾害风险评估等工作。     

Study on Synthesis and Catalytic Performance of Hierarchical Zeolite

A kind of hierarchical zeolite catalyst was synthesized by hydrothermal method. X-ray diffraction （XRD） and nitrogen adsorption-desorption method were used to study the phase and aperture structure o（ the prepared catalyst. Infrared （IR） spectra of pyridine adsorbed on the sample showed that the hierarchical zeolite really had much more Bronsted and Lewis acidic sites than the HZSM-5 zeolite. The catalytic cracking of large hydrocarbon molecules showed that the hierarchical zeolite had a higher catalytic activity than the HZSM-5 zeolite.     

用加氢裂化尾油生产润滑油基础油

天津石化公司炼油厂加氢裂化装置是轻油型的二次加工装置 ,其尾油全部用于循环。通过采用 FDW-1 0催化剂 ,对该尾油临氢降凝 ,在一定的温度、压力下 ,在实验室内得到了粘度指数大于 60的润滑油基础油馏分 ,经白土精制后完全符合润滑油基础油指标     

石墨炉原子吸收光谱法测定助燃剂中含铂量

采用石墨炉原子吸收技术 ,研究了石墨杯、普通石墨管、热解石墨管中铂的原子化行为 ,灰化和原子化条件及仪器的操作条件等。考察了盐酸、硝酸、硫酸和十几种元素对铂测定的影响 ,建立了石墨炉原子吸收光谱测定铂的方法 ,综合应用光控升温和石墨管技术 ,提高了电热原子吸收测定铂的灵敏度。通过样品分析及回收率试验 ,验证了此分析方法具有较高的准确度和精密度 ,其分析结果的变异系数 <5 .0 % ,相对误差 <± 2 .0 % ,回收率为 97%～ 10 4%。     

适用不同Brunnstrom等级患者基于表面肌电信号的动作识别方法

针对不同患病程度的脑卒中患者运动意图识别率低的问题,提出了一种适用于不同Brunnstrom等级患者基于表面肌电信号（sEMG）的动作识别方法．首先将所有等级患者sEMG数据进行融合,使用tsfresh库提取特征,然后基于随机森林（random forest,RF）模型筛选特征,并利用筛选的特征训练动作分类模型．进一步,通过研究动作和康复等级的关系,确定了康复评估动作并设计了康复等级自动评估算法．为了验证所提方法的有效性,在24例患者sEMG数据上进行了测试,实验结果表明所提方法能够将9种动作和6类康复等级的平均识别精度分别提升至89.81%和94%．基于所提方法构建的手部康复机器人系统能够实现康复等级自动评估．     

A two-level linearized compact ADI scheme for two-dimensional nonlinear reaction–diffusion equations

A novel two-level linearized compact alternating direction implicit (ADI) scheme is proposed for solving two-dimensional nonlinear reaction–diffusion equations. The computational cost is reduced by use of the Newton linearized method and the ADI method. The existence and uniqueness of the numerical solutions are proved. Moreover, the error estimates in $H^1$ and $L^{\infty }$ norms are presented. Numerical examples are given to illustrate our theoretical results.     

A Central Discontinuous Galerkin Method for Hamilton-Jacobi Equations

In this paper, a central discontinuous Galerkin method is proposed to solve for the viscosity solutions of Hamilton-Jacobi equations. Central discontinuous Galerkin methods were originally introduced for hyperbolic conservation laws. They combine the central scheme and the discontinuous Galerkin method and therefore carry many features of both methods. Since Hamilton-Jacobi equations in general are not in the divergence form, it is not straightforward to design a discontinuous Galerkin method to directly solve such equations. By recognizing and following a “weighted-residual” or “stabilization-based” formulation of central discontinuous Galerkin methods when applied to hyperbolic conservation laws, we design a high order numerical method for Hamilton-Jacobi equations. The L ² stability and the error estimate are established for the proposed method when the Hamiltonians are linear. The overall performance of the method in approximating the viscosity solutions of general Hamilton-Jacobi equations are demonstrated through extensive numerical experiments, which involve linear, nonlinear, smooth, nonsmooth, convex, or nonconvex Hamiltonians.