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11.
This article describes a new powering system for implantable medical devices that could significantly increase their lifetime. The idea is based on the substitution of the usual implantable device battery for an electric accumulator (rechargeable battery), which is fed by the electric power generated by a photovoltaic converter inside the implantable device. Light impinges on the photovoltaic device through an optical fiber going from the photovoltaic device to just beneath the patient's epidermis. Light can enter the optical fiber by passing through the skin. A complete power-by-light system has been developed and tested with a real implantable pulse generator for spinal cord stimulation. The feasibility of the proposed system has been evaluated theoretically. For example, after 13 h/week of laser exposure, the lifetime of the implantable device would increase by 50%. Other combinations resulting in lifetime increases of more than 100% are also possible. So, the proposed system is now ready to take a further step forward: in vivo animal testing. 相似文献
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目的对基于LabVIEW的医用放射性核素活度计的系统设计方案进行了硬件部分的改进。方法应用性能优良的电压/频率转换芯片VFC32实现了硬件电路设计和性能分析。利用设计的电路对医用放射性核素活度计电离室输出的电压进行信号处理,得到的频率信号通过NI公司的USB-6009 DAQ和LabVIEW8.0开发的虚拟仪器实现进一步的处理和显示。结果实验数据的图形表明改进后的系统在中低频段具有更好的线性度。结论改进后的活度计更有利于改善医用放射性核素活度计的测量精度、测量范围、低能探测限等性能。 相似文献
13.
电阻抗参数成像数据采集系统中三种电流-电压转换器的比较 总被引:1,自引:1,他引:0
目的 寻找一种能在2-380kHz间提供2MΩ以上的等效输出阻抗和0.1%以上精度的电压-电流转换电路(VIC)。为电阻抗参数成像数据采集系统的建立打下基础。方法 在分别对单运放VIC=三运放VIC和由仪表放大器的成的VIC的工作原理进行了分析的基础上,根据各自的要求建立了这3个VIC,并在不同频率点进行了测量。结果 在低频端,基于仪表放大器的VIC具有极高的输出阻抗和很低的噪声水平,在高频时只有三运放VIC性能能接近要求。结论 在电阻抗参数成像数据采集系统中应采用三运放VIC。 相似文献
14.
基于电流滞环型双闭环并网控制策略运用于模块化多电平变换器(MMC),实时监测电网电压、并网电流与给定电流误差,从而决定其网侧输出电压,使得并网电流快速、高效地跟踪给定电流;同时对并网电流脉动频率、开关频率做了详细分析,证明了该策略优越性。建立虚拟子模块,在此基础上根据子模块电容电压大小排序和桥臂电流方向,不断改变虚拟子模块与实际子模块驱动信号的循环映射关系,达到子模块电容电压动态平衡的目的。该控制方法适用于任意单元级联和任意电平数。设计了一台五电平MMC的实验样机对上述控制方法进行了实验验证。 相似文献
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John C. Norman Michael G. McGee John M. Fuqua Stephen R. Igo Stephen A. Turner Rosalyn Sterling Carlos O. Urrutia O. H. Frazier Warren C. Clay Jack A. Chambers 《Artificial organs》1983,7(1):64-73
Summary: A long-term, impĺantable, electrically actuated left ventricular assist system (THI/Gould LVAS) is being developed and characterized in vitro and in vivo for utilization in patients with end-stage heart disease. This system consists of five major components: a long-term, implantable blood pump (THI E-type ALVAD); an electrical-mechanical energy converter (Gould Model V); a control unit with batteries; a volume compensation system; and an external power supply and monitoring unit. Two of these components (blood pump and electrical-mechanical energy converter) have been integrated, and are undergoing chronic in vivo evaluations in calves. Thus far, 44 pneumatically and electrically actuated THI/Gould LVAS evaluations have been performed. This experience has resulted in >6.5 years of actuation in vivo , with durations exceeding 1 year. System in vivo performance in terms of durability, mechanical reliability, hemodynamic effectiveness, and biocompatibility has been satisfactory. Demonstration of long-term (2-year) effectiveness in supporting the circulation is the ultimate goal. 相似文献
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A new type of cardiac period meter, which allows the simultaneous collection of digital and analog records, was designed. The wave-shaper and the pulse sequencer in a digital counter were modified for the purpose of measuring successive heartbeat intervals. The output terminals of the counter were connected directly to a digital-to-analog (DA) converter. The pen-oscillograph record of the analog output produces a stair-case waveform characterized by sharp edges and stable horizontal lines. 相似文献
19.
This study investigated the air aging converter (Basic Oxygen Furnace, BOF) slag aggregate mortar with pulverized fly ash (PFA) and ferronickel slag (FNS). The chemical composition and mineralogical constituents of BOF incorporated mortar were analyzed. Setting time, flowability, compressive strength, and length change were measured to evaluate the fundamental properties of BOF mortar. The X-ray CT analysis was employed to observe the effect of converter slag in the cement matrix visually. The results showed that the hydration of BOF generated a pore at the vicinity of the aggregate, which decreased the compressive strength and increased the length change of mortar. However, the PFA or FNS incorporation of PFA or FNS can decrease the alkalinity of pore solution and subsequently reduce the reactivity of BOF aggregate. Thus, the incorporation of PFA and FNS can be a way to eliminate the disadvantage of BOF, such as volume expansion. 相似文献
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