一种简便的饮用水除铀方法及其机理

本文介绍一种利用原水中含有的无机盐,加入廉价的化学试剂除去饮用水中微量铀的简便方法。并对其除铀机理进行了探讨,证明除铀主要是以软化水过程中产生的氢氧化镁表面吸附共沉淀机理进行的。     

木素及衍生物在油田上的应用

木素磺酸盐及改性物在三次采油过程中，具有降低石油磺酸盐等阴离子型活性剂在岩石表面上的吸附损失、乳化原油，与石油磺酸盐产生协同效应，降低油、水界面张力，提高残余油回收效率的性能。介绍了木素碘酸盐的改性方法与用途。应用木素磺酸盐及改性物进行三次采油，对于有效地开采水驱残余油，降低表面活性剂驱油成本具有重要意义。     

气动人工肌肉关节的自抗扰控制

气动人工肌肉关节系统是一个强非线性时变自平衡2阶系统,鉴于传统控制方法难以克服控制精度、调节速度和稳定性之间的矛盾,设计了一种2阶自抗扰控制器.采用3阶扩张状态观测器实时估计未建模型部分及外界扰动,对系统进行线性补偿,并利用非线性反馈机制提高控制效率,在保证稳定性的前提下,提高调节速度和控制精度,使得系统的稳态精度小于...     

激波绕尖劈障碍物运动粘性流场的数值模拟研究

本文以数值方法研究了运动激波绕射的非定常粘性流的发展过程．计算中采用二阶ＴＶＤ差分格式求解二维非定常薄层Ｎａｖｉｏｒ－Ｓｔｏｋｅｓ方程，得到了清晰的流场结构图谱，分析了产生局部粘性分离的现象．研究结果表明，本文的方法可以很好地描述激波绕射的复杂流动，对流场间断有较高的捕获能力，同时表明在激波障碍物干扰的绕射场研究中局部粘性效应作用是不可忽视的重要因素     

Force Control of Electro-Hydraulic Servo System Based on Load Velocity Compensation

In an electro-hydraulic servo control system, the force servo system is an important component. However, due to the nonlinear characteristic of hydraulic systems, traditional control methods cannot achieve satisfactory control performances. To deal with this issue, a load velocity compensation algorithm based on the structural invariant principle is proposed in this paper. First, the theoretical analysis of the hydraulic and cylindrical force control system is presented, and the mathematical model of the force control system is established. Then the open-loop frequency response characteristics of the system are analyzed, in which the Bode diagram shows that the bandwidth of the system is obviously expanded after adopting the load velocity compensation algorithm. Finally, a practical hydraulic and cylindrical force servo system is introduced to validate the feasibility of the proposed controller, the experimental results demonstrate that the proposed method can improve the performance of force control and eliminate the influence of load stiffness on the dynamic characteristics of the system through a set of comparative experiments with different elastic loads.     

建筑节能墙体保温技术的研究

随着经济的快速增长,我国的能源短缺问题日益严重,节能工作成为现代社会面临的重要问题。化工企业的科技革新使得我国的建筑节能墙体保温材料成为了可能,这种材料的使用不仅符合绿色环保的要求,也降低了施工工艺的成本。本文以节能墙体保温材料出发,探讨了建筑节能墙体保温技术的实施类型,为新材料的运用提出了基础。     

利用ArcObjects实现DWG挂接MDB属性数据转入Geodatabase的方法

以某工程为例,介绍一种利用ArcObjects实现DWG挂接MDB属性数据直接转入Geodatabase的方法。     

岸基导弹远程突防航迹规划模型研究

针对岸基导弹对敌突防过程中可能面临的各类威胁源进行了量化分析,根据各威胁源的性能、特点在三维空间构建了地理障碍威胁、平台障碍威胁、恶劣气象威胁、敌防空火力与电子干扰系统威胁等不同威胁源的威胁概率函数模型,模型函数能连续、完整地表述威胁值的变化状态。在分析影响岸基导弹航迹规划因素的基础上,建立了岸基导弹航迹预规划的目标函数模型,并进行了仿真实验,仿真结果校验了所构建模型的有效性。     

浅谈“因材施教”专业英语教学——以化工专业英语为例

随着就业形势日趋严峻,用人单位对应聘者的要求越来越高。因此,高技能复合型外语人才倍受青睐。提高学生就业竞争优势已然成为高职高专教育发展的巨大挑战和必然趋势。文章通过分析化工专业英语教学现状,提出"因材施教"、学校自出教材和增大专业英语教学实习实训的几点建议。     

Design of NPR DFT-Modulated Filter Banks via Iterative Updating Algorithm

In this paper, an efficient algorithm is proposed to design nearly-perfect-reconstruction (NPR) DFT-modulated filter banks. First, the perfect-reconstruction (PR) condition of the oversampled DFT-modulated filter banks in the frequency domain is transformed into a set of quadratic equations with respect to the prototype filter (PF) in the time domain. Second, the design problem is formulated as an unconstrained optimization problem that involves PR condition and stopband energy of the PF. With the gradient vector of the objective function, an efficient iterative algorithm is presented to design the PF, which is updated with linear matrix equations at each iteration. The algorithm is identified as a modified Newton’s method, and its convergence is proved. Numerical examples and comparison with many other existing methods are included to demonstrate the effectiveness of the proposed method.