Material selection methodology for radio frequency (RF) microelectromechanical (MEMS) capacitive shunt switch

Microsystem Technologies - This paper describes the process of selecting the most optimum Radio Frequency Micro- electro- mechanical-systems (RF-MEMS) switch design using Ashby’s methodology....     

Development of a novel radio frequency identification chipless tag with multifrequency response

This article presents an innovative contribution, which is the design of a novel radio frequency identification chipless tag characterized by a reduced size and a multifrequency response. It consists of a microstrip grounded structure based on a circular patch coupled with meandered metal strip. The adopted approach is an encoding frequency approach that ensures a capacity of 20 data bits in the ultra wideband. The main aim of this contribution is to introduce a novel configuration resulting from the study of the classic principles of the chipless tag design. It focuses on the design of an encoding surface associated with the same shape having the role of the transmitter/receiver antenna in order to mainly gain time to work on another tag component. The tag is analyzed, optimized, and measured to validate its feasibility and to prove the possibility of its commercial application.     

A modelling and simulation approach for radio frequency (RF) parasitic effects reduction in wafer-level packaging (WLP) of RF-MEMS passive components

Microsystem Technologies - RF-MEMS, i.e. micro electro mechanical-systems (MEMS) for radio frequency (RF) passive components, started to make their way into mass-market applications in the...     

Investigation of the impact on the radio frequency (RF) behaviour of electrically conductive adhesives (ECAs) used in wafer-level packaging (WLP) of RF-MEMS

Microsystem Technologies - In this work, an anisotropic conductive adhesive (ACA), belonging to the family of electrically conductive adhesives (ECAs), exploited for the wafer-level bonding phase...     

复杂化工流程的优化及在DOPS上的实现(I)复杂化工流程的优化策略

在数据驱动的化工流程模拟系统ＤＯＰＳ（ＤａｔａＯｒｉｅｎｔｅｄＰｒｏｃｅｓｓＳｙｓｔｅｍ）中采用逐次二次规划，实现了一个通用的复杂过程优化系统。本系统的规格化由系统根据变量、约束条件的上下限和初值自动进行，也可以在界面上由用户给出。本系统在流程扰动过程中引入Ｐ矩阵以简化流程计算提高计算速度，利用模块的中间结果提高了模块的计算效率，改善了系统的收敛性能。     

RLL（2，12；8，15）调制码设计与FPGA实现

在分析现有光盘调制码的基础上,提出了一种新的RLL(2,12;8,15)编码。给出了码的构造方法和编解码步骤,并与几种常见的游程长度受限码进行了比较,分析了其优缺点,在FPGA上完成硬件实现。     

Ergonomic evaluation of the musculoskeletal risks in a banana harvesting activity through qualitative and quantitative measures,with emphasis on motion capture (Xsens) and EMG

The objective of this study was to evaluate the risk of musculoskeletal injuries in a banana processing task. A sample of three workers were evaluated with the Nordic questionnaire as well as according to effort, discomfort and usability levels, hand grip dynamometry, inertial sensor motion capture (Xsens) and surface electromyography in the right arm. The workers had musculoskeletal complaints throughout the spine and hips, low effort and discomfort levels, and a satisfactory usability level. The hand grip strength values (dominant: 54.8 Kgf; non-dominant: 54.2 Kgf) were above the reference values for the Brazilian population. Regarding movement analysis, we identified risks related to cervical protrusion, forward and lateral trunk flexion, abduction and flexion in the shoulders, flexion, extension, radial and ulnar deviation in the wrists, as well as repetitive movements. Surface electromyography showed that the greatest demand during the task was on the extensor carpi radialis, although the trapezius and flexor carpi radialis showed a tendency toward fatigue. Thus, the set of evaluations showed that the tool used and worker adaptation to the position of the bunches, together with the repetitious movement, led to inadequate postures and musculoskeletal risks.Relevance to industryThe banana processing activity generates employment and income in several regions of the world and in Brazil. However, it is still rudimentary and may present risks to the worker's health. This study seeks to elucidate ergonomic risks through technological instrumentation in order to have a quantitative assessment of the ergonomic risks.     

Serial‐fed linear frequency diverse arrays for obtaining direction of arrival (DOA) of frequency modulated continuous waveform (FMCW) sources with ambiguity reduction

Possibility of exploiting serial‐fed linear arrays for obtaining the direction of arrival (DOA) of frequency modulated continuous waveform (FMCW) sources is discussed in this article. The angle of incident wave is assumed to be in the range, [?90°, 90°] , with ambiguity reduction compared with the previous work. At first, the serial‐fed arrays are assumed as a transmitter with triangular FMCW sources, composing modified frequency diverse arrays. An explicit angle dependency is obtained on the separations between the maximums of the produced spatial power pattern in a design procedure. The approach is generalized for modified sawtooth frequency modulated continuous waveform (SFMCW) sources, which are combinations of two SFMCW sources with two different slopes of frequency shifts. In addition, a measurement setup is implied assuming the serial‐fed array as the receiver and an antenna with a known FMCW source and an unknown DOA as the transmitter. The DOA will be obtained from the separations between maxima of the received signals. Advantages of the proposed structure are the simplicity of antenna structure, ability of operation with narrowband antenna elements, and ambiguity reduction compared with the previous work.     

优化伪随机脉冲位置调制序列激励的无串扰超声测距系统

超声测距系统中多路换能器同时工作存在的串扰会导致错误的距离测量和降低系统的工作效率.为消除此串扰,提出伪随机脉冲位置调制(PPPM)法用于构造超声发射序列.PPPM序面中脉宽固定,脉冲位置由伪随机数序列调制.为获得满面春风锐的自相函数和平坦的互丰关函数,对四种常用的同余法产生的伪随机数进行了定量检验,并选定统计特性最好的系列静电型换能器构成的超声测距系统,实验验证了所提方法的可行性.     

双馈型变速恒频风力发电系统的鲁棒控制

研究了双馈变速恒频风力发电系统的鲁棒控制问题. 采用定子磁场定向的矢量变换技术, 建立了系统非线性数学描述, 利用非线性鲁棒控制技术, 设计了能实现发电机输出有功功率和无功功率鲁棒解耦控制, 同时具有鲁棒干扰抑制作用的转子励磁控制器. 理论分析和仿真结果均表明, 所设计的控制器可以保证在风速变化、系统参数不确定性和外部干扰的情况下, 风力发电系统仍能安全可靠地最大获取风能, 并且输出恒频恒压的电量.     

应用微机理论研究Ni(pz)_4Cl_2型络合物的光、热、磁性质

利用d8 (D 4h)全组态统一晶场理论模型 ,研究了Ni(pz) 4Cl2 型化合物能量矩阵的特征值、特征矢以及计算其ZFS、EPR参量的计算方法 ,并利用该方法拟合出了Ni(pz) 4Cl2 型化合物的光谱、ZFS和EPR参量 ,总结出利用微机对其拟合的一般规律 ,计算结果与实验值一致。