Optimization of waste quail eggshells as biocomposites for polyaniline in ammonia gas detection

A simple, cost-effective, and novel chemical sensor for ammonia (NH₃) gas detection was developed from polyaniline (PANI)/quail eggshell (QES) composites. QES is a natural waste enriched in calcium carbonate. In this work, pure PANI was synthesized from chemical oxidation method and PANI/QES composites were prepared from physical mixing of QES with the synthesized PANI at different mass ratio. A series of complementary techniques including Fourier transform infrared and ultraviolet-visible spectrometers, scanning electron microscope with energy dispersive detection coupled with mapping, thermogravimetric analysis, and X-ray diffractometer were used to characterize the physicochemical and textural properties of the biocomposites. From the results, PANI/QES composite with a mass ratio of 1 exhibited the lowest NH₃ detection limit of 5.24 ppm with a linear correlation coefficient (R²) of close to unity (0.9932) between the signal and NH₃ gas concentration. As a whole, the PANI/QES biocomposites synthesized from this work exhibited excellent selectivity toward NH₃ gas even in the presence of other gas impurities, such as acetone, ethanol, and hexane. For the sensor reusability, the PANI/QES biocomposites can be reused in the application of NH₃ gas detection for at least 4 cycles.     

0.88C-1.2Si-0.75Mn-2Al高强度电缆铠装钢用盘条的试制

采用中高碳成分添加低密度元素Si、Al进行轻量化的设计思路设计了试验钢的化学成分,试验钢采用50 kg真空感应炉冶炼。利用金相显微镜、SEM扫描电镜和力学性能检测设备对试制后的Φ6 mm盘条进行了显微组织观察、珠光体片层间距的测量和屈服强度、抗拉强度、延伸率的检验。结果表明:盘条在600℃等温2 h后的金相显微组织为铁素体+珠光体的混合组织,珠光体的片层间距为(126±5) nm,屈服强度大于1 183 MPa、抗拉强度大于1 425 MPa、延伸率大于10%,其力学性能满足电缆用铠装钢的技术要求。     

A visual tool for computer supported learning: The robot motion planning example

We introduce an effective computer aided learning visual tool (CALVT) to teach graph-based applications. We present the robot motion planning problem as an example of such applications. The proposed tool can be used to simulate and/or further to implement practical systems in different areas of computer science such as graphics, computational geometry, robotics and networking. In the robot motion planning example, CALVT enables users to setup the working environment by creating obstacles and a robot of different shapes, specifying starting and goal positions, and setting other path or environment parameters from a user-friendly interface. The path planning system involves several phases. Each of these modules is complex and therefore we provide the possibility of visualizing graphically the output of each phase. Based on our experience, this tool has been an effective one in classroom teaching. It not only cuts down, significantly, on the instructor’s time and effort but also motivates senior/graduate students to pursue work in this specific area of research.     

Characterizing Performance Variation of Product Designs

Quality and reliability design practitioners have utilized Taguchi's methodology of matrix experimentation to generate computer simulation data for characterizing performance variation of product designs. However, the sampling strategy employed renders computer implementation of matrix experimentation cumbersome and statistically invalid. Weaknesses of this approach also include sample size limitation and overestimation of performance variation. An alternative approach that combines Monte Carlo simulation with the strategies of independent sampling across runs and correlated sampling between runs is presented. An application case study shows that the proposed approach constitutes an improvement on the matrix approach with respect to statistical validity and estimation accuracy.     

游艇概念设计方法与技术研究

针对游艇的概念设计方法与技术展开研究,从创意设计思维层面入手,建立了游艇设计概念引入、意象及内涵深化的设计创意库,包括海洋生物库、东方文化符号库、其它类产品创意库等三大类;分析了游艇概念设计从抽象到具体的过程,提出了游艇创意概念设计的底影套模法;探讨了游艇设计的参数化、模块化实现技术。     

有源电光调制式高功率瞬态电场传感器的研制

瞬态电场防护及应用技术的研究离不开瞬态电场测试系统;文中基于有源电光调制法,研制了一种高功率瞬态电场传感器;通过建立该传感器的等效电路模型,并借助CST仿真建模,分别从频域和时域角度分析了传感器的接收特性,并得到了一致的结果;最后利用脉冲噪声模拟器和吉赫兹横电磁波小室对研制的传感器性能进行了测试;结果表明:接收天线为单极子天线,天线负载采用高阻时响应电压与被测电场场强成正比;研制的传感器带宽为10kHz～314MHz,可用于纳秒级高功率瞬态电场的时域测试。     

基于RLS-DLUKF算法的锂电池SOC预测方法研究

本工作以钴酸电池为研究对象,针对锂电池在复杂工况下电流的剧烈变化导致荷电状态(SOC)无法有效预测的问题,建立了以精确参数为基础的双层无迹卡尔曼滤波算法(DLUKF)架构来更精准的估算SOC.首先,以脉冲功率特性实验数据获取二阶电路模型中电池开路电压与荷电状态的函数关系及特性曲线;其次,为增强模型辨识过程中的自适应学习能力并解决模型参数估计不准确的问题,应用递推最小二乘(RLS)算法在线准确地识别出模型中的未知变量;最后根据输入的变量信息,利用UKF算法相互嵌套形成的DLUKF算法实现对SOC的快速预测来解决单一的UKF算法在高阶非线性系统里估算不准确、精度低的问题.在UDDS工况和FUDS工况下对DLUKF算法和单一的UKF算法进行比较,通过对比分析两种算法估计出的SOC曲线、SOC误差曲线、端电压曲线及端电压误差曲线,表明DLUKF算法预测SOC的平均误差比UKF的低且预测精度更高.     

配电自动化模式下配电网保护的模式选择和整定计算

配电自动化设备大量使用在配电网中,目前配电网的继电保护配置只有在66 kV变电站10 kV出口配置,缺乏对配电网的整体准确计算,提出配电网故障电流的计算,基于故障电流对配电自动化设备继电保护定值进行配置,包括保护模式的选择、配电网网架的改造以及配电自动化设备的优化布局。     

基于线性约束最小方差的全球定位系统抗干扰技术

针对全球定位系统（ GPS）接收机在强宽带干扰下无法正常工作的情况,采用自适应调零天线,利用信号和干扰的入射空间角度不同进行空域滤波,可提高其抗干扰能力。理论分析和仿真结果表明,基于线性约束最小方差（ LCMV）准则的自适应滤波算法简单有效,在牺牲一个干扰抑制自由度的条件下,可对高仰角卫星导航信号进行较好的保护。