基于变压器反馈的平坦噪声系数超宽带CMOS低噪声放大器

在系统中集成超宽带(UWB)收发机芯片用于支持室内定位正成为移动通信终端技术发展的一个重要趋势.在超宽带收发机中,低噪声放大器(LNA)是一个核心功能模块.超宽带的全频段(3.1～10.6 GHz)覆盖要求给低噪声放大器的设计带来了巨大挑战,尤其是需要在宽带匹配及在带内维持平坦的噪声系数的情况下.传统的低噪声放大器架构应用在超宽带设计时,噪声、增益和输入匹配之间存在较明显的性能折中关系,因此无法达到良好的综合性能指标要求.本文采用基于变压器反馈的输入匹配的第一级架构和多功能第二级输出驱动结构,实现了平坦的噪声系数和高增益等性能.基于TSMC 65 nm工艺设计的电路仿真结果表明,该低噪声放大器在3.1～10.6 GHz全频段内,可实现输入匹配S_(11)-10 dB,增益17 dB,噪声系数2.71±0.28 dB,1-dB压缩点-17.5 dBm等指标,电路整体功耗为32.8 mW.因此,综合性能Ⅰ(FoM-Ⅰ)和综合性能Ⅱ(FoM-Ⅱ)分别可达2.32和0.41.     

直动式电反馈高压电气比例减压阀的研制

介绍一种新型的直动式电反馈高压电气比例减压阀的结构原理。实验结果表明，该减压阀调压范围宽，调压精度高，具有较好的静、动态特性。     

国外现代铝带冷轧机和国产先进冷轧机

介绍了国外现代化铝带冷轧机的特点和典型轧机及国内铝带冷轧机的发展。     

SEQUENTIAL LOOP CLOSING IDENTIFICATION OF MULTIVARIABLE PROCESSES USING THE BIASED RELAY FEEDBACK METHOD

Each controller in multiloop control systems for multivariable processes can be tuned sequentially with the ultimate information for the paired input and output while former loops have been closed, and hence, single-input single-output autotuning methods can be applied. In this sequential autotuning for multiloop control systems, several iterations are usually required for better control performances. Especially when pairings are undesirable, the autotuning sequences should be repeated with correct pairings, which result in long field experiments. Here, to avoid this drawback, a simple method to identify process models while loops are being sequentially tuned is proposed. The identified models can be used to correct pairings of multiloop control systems and to improve tuning performances without several field iterations. In addition, they can be used to obtain model-based control systems such as decoupling control systems.     

Testing usability and trainability of indirect touch interaction: perspective for the next generation of air traffic control systems

This study aims to determine whether indirect touch device can be used to interact with graphical objects displayed on another screen in an air traffic control (ATC) context. The introduction of such a device likely requires an adaptation of the sensory-motor system. The operator has to simultaneously perform movements on the horizontal plane while assessing them on the vertical plane. Thirty-six right-handed participants performed movement training with either constant or variable practice and with or without visual feedback of the displacement of their actions. Participants then performed a test phase without visual feedback. Performance improved in both practice conditions, but accuracy was higher with visual feedback. During the test phase, movement time was longer for those who had practiced with feedback, suggesting an element of dependency. However, this ‘cost’ of feedback did not extend to movement accuracy. Finally, participants who had received variable training performed better in the test phase, but accuracy was still unsatisfactory. We conclude that continuous visual feedback on the stylus position is necessary if tablets are to be introduced in ATC.     

基于状态聚类的多站点CSPS系统的协同控制方法

单站点传送带给料加工站（Conveyor-serviced production station,CSPS）系统中,可运用强化学习对状态——行动空间进行有效探索,以搜索近似最优的前视距离控制策略.但是多站点CSPS系统的协同控制问题中,系统状态空间的大小会随着站点个数的增加和缓存库容量的增加而成指数形式（或几何级数）增长,从而导致维数灾,影响学习算法的收敛速度和优化效果.为此,本文在站点局域信息交互机制的基础上引入状态聚类的方法,以减小每个站点学习空间的大小和复杂性.首先,将多个站点看作相对独立的学习主体,且各自仅考虑邻近下游站点的缓存库的状态并纳入其性能值学习过程;其次,将原状态空间划分成多个不相交的子集,每个子集用一个抽象状态表示,然后,建立基于状态聚类的多站点反馈式Q学习算法.通过该方法,可在抽象状态空间上对各站点的前视距离策略进行优化学习,以寻求整个系统的生产率最大.仿真实验结果说明,与一般的多站点反馈式Q学习方法相比,基于状态聚类的多站点反馈式Q学习方法不仅具有收敛速度快的优点,而且还在一定程度上提高了系统生产率.     

基于输出反馈滑模控制的分数阶超混沌系统同步

以具有更大秘钥空间的分数阶超混沌系统为驱动系统和响应系统,利用具有实际应用意义的输出反馈滑模控制实现两个系统的同步.通过对同步误差系统方程进行结构分解,在辅助系统的基础上设计具有输出反馈特性的滑模控制律.在分数阶系统稳定性理论基础上利用MATLAB YALMIP工具箱对滑模参数进行整定,并利用分数阶Lyapunov稳定性定理证明了滑模控制律和自适应滑模控制律的稳定性.最后,数值仿真表明了本文方法的有效性和可行性.     

水泥棒磨机预粉磨技术的增产节能效果

随着水泥工业结构调整，传统的一级圈流短磨水泥粉磨系统已经难以满足高产、优质、低耗的产业政策要求，必须进行必要的技术改造。文章分析了一级圈流磨存在的技术问题及其产生原因，介绍了对其实施增产节能改造的系统工艺技术方案和主机设备的内部结构改造方案。从两个厂的改造实施情况看，技改效果显著。     

Effects of real‐time visual feedback on pre‐service teachers' singing

This pilot study focuses on the use real‐time visual feedback technology (VFT) in vocal training. The empirical research has two aims: to ascertain the effectiveness of the real‐time visual feedback software ‘Sing & See’ in the vocal training of pre‐service music teachers and the teachers' perspective on their experience with VFT. Forty participants from an undergraduate music teacher education programme were randomly assigned to three groups. The first two groups were assigned the teacher and student versions of Sing & See, respectively, and the third group served as a control group without access to the software. The experimental groups were given 12 weeks to use the software for vocal training on a self‐regulated basis. The technique of complex selections (TCS) was designed to assess the pitch accuracy and richness of vocal timbre. Pre‐ and post‐test singing tasks showed that the participants from the experimental groups significantly improved their vocal timbre. A questionnaire survey conducted after the training period found that most of the participants in the experimental s were positive about the effectiveness of VFT software in vocal training. As future leaders in the implementation of music education technology, pre‐service music teachers expressed a positive attitude towards the use of VFT as a technology‐enhanced learning (TEL) component in music education.     

Design of a slave arm of a surgical robot system to estimate the contact force at the tip of the employed instruments

Acquisition of the contact force at the instrument tip can enable better performance, e.g. transparency of the haptic feedback in the surgical robot systems. It is, however, difficult to measure the contact force directly due to technical limitations in attaching sensors to the tip of the instruments. This paper proposes a method to estimate the forces by installing the sensors away from the instrument tip. The proposed method employs specially designed mechanical parts of the slave robot, i.e. a slider cover plate for the z-axis translational force along the insertion direction, and docking clamps for the rotational pivot torques around the fulcrum point. Strain gauges are attached to specially designed places with enhancing shapes. The simulation results of the force estimation are presented to confirm the strain concentration area. The proposed method is validated with quantitative experimental results. Calibrated weights are determined upon the comparison of the strain value with a calibrated 6-axis force/torque sensor. The percentage error in the force calibration is about 5~8% calculated by the root mean square error (RMSE) of force-sensing performance. In addition, it can be computed by considering only the bending phase of each sensor although the hysteresis is observed from the calibration graph.