Small-organ dynamic imaging system

Dynamic ultrasonic imaging of superficial body organs adds a new dimension to clinical sonographic examinations in that it enables the real-time evaluation of tissue motion and vascular pulsations. A high-frequency (7.2 MHz) linear-array system has been newly developed that generates simultaneous A- and B-mode displays at 60 frames/sec. The instrument produces real-time scan-converted images in standard television format for direct viewing on television (TV) monitors or clinical recording through videotape equipment. Clinical application of this dynamic imaging system has increased the diagnostic capabilities of ultrasound in ophthalmology, radiology, and pediatrics.     

变频调速系统在恒压供水中的应用

变频器交流调速系统在风机、水泵的控制中得到了广泛应用,它具有节约能源,提高经济效益等优点。重点介绍了变频器交流调速控制系统在一次水能源供应系统的应用和控制方法。     

新型X射线指示装置的研究设计

目的：在辐射防护领域中设计和研制一种X射线指示装置,用于医用放射设备机房外时时指示X射线产生情况,有效地保护患者和医务工作者的健康。方法：利用闭环霍尔电流传感器,对医用放射设备的供电电流进行检测,一旦超过X射线产生时的阀值电流,将启动指示装置。结果：该电路在不对原设备进行任何改动的条件下,可以时时指示医用放射设备X射线的产生情况。结论：新型X射线指示装置电路制作成本低,功耗远低于传统的X射线防护指示灯,实现了医用放射设备X射线的产生与指示同步,切实做好辐射防护工作。     

应用于超声成像的数据采集系统设计

数据采集系统在全数字医用超声成像设备中占有重要地位.本文介绍了应用于超声成像的数据采集系统的设计方案.系统采用AD9228芯片（Analog Devices Inc）作为模数转换芯片,使用现场可编程门阵列（FPGA）与静态随机存储器（SRAM）构成相关控制、缓存等数字电路模块,使用ISE组件Chipscope对采样结果进行测试.测试结果表明：系统采集样本正确;FPGA准确接收采样数据的输出,并完成串并联转换、缓存等处理;系统可以稳定地工作在40MHz的数据采集与存储速率下,符合医用超声成像系统的使用要求.     

汽油发动机排放物经三元催化器催化前后苯系物的健康风险评价

目的比较三元催化器催化前后汽油机中苯系物排放的健康风险的改变情况,探讨健康环境风险评估方法在汽油机排放物健康效应评价中的可行性。方法采集分析100%负荷下三元催化器进气口和出气口中苯系物(苯、甲苯、二甲苯)的浓度,利用健康环境风险评估方法比较催化前后苯系物健康风险的变化。结果在100%负荷下经三元催化器催化后,甲苯、二甲苯的危害指数降低,苯的危害指数和致癌风险升高;苯系物的慢性长期健康危害指数降低。结论三元催化器改变了汽油机排放物的健康风险,催化后苯系物的非致癌风险降低,致癌风险增加。健康环境风险评估可以用于汽油机排放物的健康效应。     

An elite hybrid strategy for solar photovoltaic system based optimized cascade controller under uniform and partial shading conditions

A hybrid technique for maximum power point tracking (MPPT) for a photovoltaic (PV) system is proposed in this paper. The proposed hybrid system is combination of Wing suit Flying Search (WFS) and modified Transient search optimization (MTSO), therefore it is called WFS-MTSO method. The proposed controller has three processes: (i) to identify the operating level of photovoltaic (uniform or in PSC), (ii) to estimate the maximal power point using WFS technique, and (iii) to ensure the photovoltaic system runs on the estimated maximum power point (MPP) by MTSO optimized cascade controller. This method begins with a sense of irradiance and temperature. The proposed photovoltaic system has two components. The first one is WFS maximal power point tracking algorithm attain maximal power point. The second one is MTSO optimized cascade controller to force the photovoltaic system to activate at maximal power point. Here, the proposed hybrid technique is utilized at MPPT to diminish tracking error and oscillation across MPP for optimizing power output. The proposed optimized cascade control improves the system efficiency by averting interruptions previously they propagate to the system. Finally, the performance of proposed hybrid system is executed on MATLAB/Simulink working platform and the performances are compared with various existing approaches. The statistical matrices, like mean, median, and standard deviation is analyzed the tracking efficiency of the proposed WFS-MTSO approach.     

Experimental investigation of Harris Hawk optimization-based maximum power point tracking algorithm for photovoltaic system under partial shading conditions

An integrated quasi Z-source DC–DC converter (qZSC) along with Harris Hawk Optimization (HHO)-based maximum power point tracking (MPPT) algorithm is proposed in this paper to increase the efficiency of photovoltaic (PV) system. The qZSC-based PV system experiences more voltage and current stress during partial shading conditions (PSCs), which causes overheat on qZSC components hence, degrade the efficiency and reliability of the system. Conventional swarm intelligence-based MPPT algorithms track the G_MPP during PSC, but these take longer convergence time and fail to settle at G_MPP. This uncertainty of finding the G_MPP leads to fluctuations at output of qZSC, hence more stress on the converter components. HHO in tracking the G_mpp eliminates premature local MPPs, enhances convergence speed by expanding the search space for finding the G_MPP. The proposed system is developed in MATLAB/Simulink environment and verified the results by developing prototype model in the laboratory by using C2000™ Piccolo™ Launch Pad™, LAUNCHXL-F28027 controller. The tracking performance of the proposed HHO-based MPPT algorithm is tested under fast changing and PSCs in comparison with perturb & observe (P&O), particle swarm optimization (PSO), and artificial bee colony (ABC)-based MPPT algorithms. The simulation and experimental results show that the proposed HHO-based MPPT algorithm is robust, tracks maximum power point in minimum convergence time in comparison with P&O, PSO and ABC-based MPPT algorithms. Hence, voltage and current fluctuations at the output of qZSC are reduced. Therefore, voltages and current stress on qZSC components are reduced and the efficiency of the system is improved.