X线摄影放大装置的研制及临床应用

介绍了X线摄影放大装置,利用X线几何投影和光学成像原理,采用单片机软件编程,通过光耦技术和变频调速技术,实现仪器的自动控制。临床试验表明,该X线放大装置用于摄取开放大人体小部位的病灶是可行的。     

基于全响应功率补偿的电压型PWM整流器直接功率控制

为提高直流环节的动态响应,抑制功率突变时的母线电压波动,本文在建立双PWM变频调速系统能量平衡数学模型的基础上,将无功电流引入功率调节环,采用输出功率直接反馈,首次提出动态和稳态分步补偿的全响应直接功率控制策略,即以功率为控制量,对稳态所需能量进行实时性补偿,对动态所需能量以n个期望控制周期为单位进行阶段性补偿。实验结果表明,改进后的电压型PWM整流器控制策略显著提高了直流环节的动态响应,且有效抑制直流母线电压波动,实现了对双PWM变频系统能量流动的精确控制和协调性能的提升。     

一种新型B超数字扫描变换系统的设计方法

针对B超设备小型化以及扫描图像存储容量大的要求,本文提出了一种基于FPGA和DDR SDRAM结构的新型的数字扫描系统的设计方法;介绍了相应的逻辑设计流程和系统实现的关键技术。仿真结果和实验结果表明,该系统为实现B超的小型化需求提供了途径。     

Thermoelectric Oxide Modules (TOMs) for the Direct Conversion of Simulated Solar Radiation into Electrical Energy

The direct conversion of concentrated high temperature solar heat into electrical energy was demonstrated with a series of four–leg thermoelectric oxide modules (TOM). These temperature stable modules were not yet optimized for high efficiency conversion, but served as proof-of-principle for high temperature conversion. They were constructed by connecting two p- (La_1.98Sr_0.02CuO₄) and two n-type (CaMn_0.98Nb_0.02O₃) thermoelements electrically in series and thermally in parallel. The temperature gradient ΔT was applied by a High–Flux Solar Simulator source (HFSS) which generates a spectrum similar to solar radiation. The influence of the graphite layer coated on the hot side of the Al₂O₃ substrate compared to the uncoated surface on ΔT, P_max and η was studied in detail. The measurements show an almost linear temperature profile along the thermoelectric legs. The maximum output power of 88.8 mW was reached for a TOM with leg length of 5 mm at ΔT = 622 K. The highest conversion efficiency η was found for a heat flux of 4–8 W cm^-2 and the dependence of η on the leg length was investigated.     

一种高性能价格比的B超用数字扫描变换器

数字扫描变换器是B超诊断仪中的一个关键部件。本文提出了一种新颖的数字扫描变换器设计方案。它以递推算法和圆插补技术为基础,采用小存储器结构,不仅获得了失真小的高质量图像,而且具有部件成本低、硬件规模小等特点。实践证明,它具有很高的性能价格比与推广应用价值。文中详细说明了系统的工作原理,并给出了有关的实验结果。     

某企业转炉炼钢一次烟气处理职业病危害因素控制效果评价

目的对某企业转炉炼钢一次烟气进行职业病危害因素控制效果评价,为建设项目的设计提供必要的职业病危害防护对策和建议,评价职业病防护措施的"三同时"与主体工程同时设计,同时施工,同时投入生产和使用的效果。方法采用现场职业卫生学调查、工作场所职业病危害因素检测相结合。结果该次共检测各种职业病危害因素46点次的粉尘、高温、热辐射、噪声和各种毒物,检测结果均符合国家职业卫生标准。结论该建设项目各种职业病危害因素均在国家职业卫生限值之内,反映该项目烟气处理效果较好,符合国家相关职业卫生标准、规范。     

Band-Pass Filtering Cross-Polarization Converter Using Transmitarrays

Microwave devices with polarization conversion and band-pass filtering response have great application prospects on radomes. Here, the concepts of band-pass filters and cross-polarization converters are combined to realize a band-pass filtering cross-polarization converter with an extremely high polarization-conversion ratio. Most importantly, the device has an excellent out-of-band rejection level, above 30 and 40 dB for the lower and upper edges, respectively. In addition, the transmission zeros of the passband can be flexibly tuned independently. The band-pass filtering polarization converter was simulated, fabricated, and measured, and the measured results were found to be in good agreement with the simulation results.     

心电图机的网络化改造

目的：改造具有COM接口的老型号心电图机,使其支持网络传输。方法引入信号转换器,将心电图机COM口输出信号转换为无线网络信号,然后输出到医院信息网络。结果改造后的光电9000系列心电图机具备了无线网络传输功能。结论该改造方案具有较强的可行性,值得临床应用。     

不同输出功率对覆膜型激光光纤光热转换效应的影响

目的 探讨不同输出功率对覆膜型激光光纤光热转换作用的影响,为光纤尖端光热转换后激光能量分布提供有效预测平台.方法 建立光纤尖端输出功率及温差变化监测模型,光纤尖端进行光热转换前后使用红外成像测温仪器测量光纤尖端在不同的输出功率(100 mW、200 mW、300 mW、400 mW、500 mW、600 mW、700 ...     

基于UC3842芯片的医用开关电源设计

以UC3842芯片为核心,提出了一种医用开关电源设计方案。首先阐述了UC3842的基本原理,在此基础上提出了单端反激开关电源的原理和设计方法。UC3842是Unitorde公司推出的电流型脉宽调制器,该调制器单端输出,可以直接驱动双极型功率管或场效应管,适用于无工频变压器的20~80 W小功率开关电源的设计。文章介绍的设计方案采用单端反激式结构,实现宽电压输入,稳定的直流输出,具有输入纹波小,输出稳定,体积小,质量轻,效率高,电磁兼容好等优点,能够很好地满足医疗设备供电需求。