Effect of Synthesis Technique and Carbonate Content on the Crystallinity and Morphology of Carbonated Hydroxyapatite

The syntheses of nanosized carbonated hydroxyapatite（CHA） were performed by comparing dropwise and direct pouring of acetone solution of Ca（N0₃）₂-4H₂0 into mixture of（NH₄）₂HP0₄ and NH₄HCO₃ at room temperature controlled at pH 11.Direct pouring method was later applied to study the increment of carbonate content in syntheses.The as-synthesized powders were characterized by various characterization techniques.The crystallographic results of the produced powders were obtained from X-ray diffraction analysis,whilst the carbonate content in the produced powders was determined by the CHNS/O elemental analyzer.Fourier transform infrared analysis confirmed that the CHA powders formed were B-type.Field emission scanning electron microscopy revealed that the powders were highly agglomerated in nanosized range and hence energy filtered transmission electron microscopy was employed to show elongated particles which decreased with increasing carbonate content.     

Development of Sensor and Control Systems of a Wearable Robot to Walk on a Step

The goal of our study is to develop a system for walking on a step using a wearable robot. Our system consists of (1) sensing of a step from the movement of the walker, (2) detection of the foot placement state related to the step, and (3) generation of gait patterns of climbing and stepping down for the step. In the generation of gait patterns for the step, toe trajectories are generated according to the height of the step to avoid collision of the swinging leg with the step. The hip trajectory is generated by an optimization technique that minimizes the sum of the joint angular jerk of the robot subject to constraints on the hip position and the velocity at toe liftoff. Each joint angle trajectory is calculated from the generated trajectories by means of inverse kinematic equations. We investigated the feasibility of the proposed sensor and control systems for two steps with different heights.     

热风炉冷风放风阀带压更换

分析了热风炉冷风放风阀更换情况,利用冷风放风阀工作特性实现带压更换,效果良好.     

光谷大桥桥面铺装设计及施工

介绍了武汉光谷大桥（庙湖段）防水粘结体系的选择及Eliminator体系的防水设计,详细阐述了该桥面喷砂除锈、防水粘结体系和浇注式混合料GA10的施工工艺流程,并提出了相关施工控制重点.     

羽毛绒含水率测定的不确定度评估

采用标准不确定度的A类评估对羽毛绒含水率测量过程中各种影响因素进行了分析。通过找出各影响因素的分量，进行测量不确定度的评估，从而使确定产品的合格与否更加可信。     

一种带改进开关和使用新型按比例缩小策略的10位120兆的流水线模数转换器

这篇文章介绍了一种精度为10比特,采样率为120兆的双通道流水线模数转换器(ADC)。这个模数转换器利用了体效应来改善开关的导通性能。在版图绘制中应用了一种新型的按比例缩小的策略。基于0.18μm的CMOS工艺,ADC的整个版图面积为2.05x1.83 mm2。在采样频率为120兆,输入信号频率为4.9兆的情况下,无杂散动态范围达到了74.32dB,信号噪音失真比为55.34dB,3伏供电电压下每通道的功耗为220毫瓦。     

一种基于频分复用信号的宽带数字收发设计

介绍了一种基于频分复用信号的宽带数字收发设计。根据软件无线电基本理论给出了系统的硬件具体实现和软件处理流程,描述了基于FPGA平台的并行FIR滤波器和并行CIC滤波器的高效实现方法。给出了宽带数字收发系统的仿真和测试结果。该系统硬件结构简洁,逻辑资源开销小,通用性和扩展性强。     

建筑施工混凝土浇筑技术研究

混凝土浇筑技术决定着建筑工程质量的好坏,甚至还影响着整个工程的安全以及成本造价。因此,在实际工程施工过程中要严格督察混凝土浇筑问题。本文就建筑施工混凝土浇筑技术进行浅析,主要对目前国内建筑混凝土浇筑技术的概况以及浇筑前期准备和浇筑技术进行探讨。