基于新型四象限开关单元的并联型有源滤波器

提出了一族基于新型四象限开关单元的并联型有源电力滤波器(Parallel Active Power Filter,PAPF)拓扑。它实质上由降压型最小功率单元通过有机方式组合而成,解决了传统有源滤波器拓扑的桥臂直通隐患,且具有可高频、高效率运行的优点。本文以一种半桥型交错降压有源滤波器(IB-APF)为例,详细分析研究了其工作原理,给出了其控制策略,仿真和实验结果验证了这种新型有源滤波器的可行性。该族有源滤波器特别适合于高可靠性的场合,同时具备优良的补偿性能。     

下腔静脉滤器血栓形成局部置管溶栓与外周静脉溶栓治疗的比较

目的对比局部置管溶栓和外周静脉溶栓治疗在下腔静脉滤器血栓形成中的溶栓疗效,缩短滤器植入时间,提高滤器取出率,降低滤器永久植入后中远期合并症。方法采用单中心前瞻性研究的方法,收集2013年2月至2014年8月期间北京积水潭医院血管外科收治的创伤性下肢骨折合并深静脉血栓并放置可回收性腔静脉滤器(Opt Ease)的患者,下腔静脉造影或彩超发现滤器下血栓≥1.0 cm者,采用随机数字表法分组,进行外周溶栓或导管溶栓治疗,对滤器的取出率进行对比分析讨论。结果外周溶栓组30例,滤器取出11例,取出率36.7%,导管溶栓组30例,滤器取出24例,取出率80.0%,导管溶栓组取出率明显高于外周溶栓取出率(P<0.05);两组间溶栓治疗后血栓大小变化的对比,导管溶栓组的溶栓效果优于外周溶栓组(P<0.05)。滤器取出后无再发肺栓塞表现。结论在下腔静脉滤器血栓形成中局部置管溶栓效果明显优于外周静脉溶栓治疗。     

下腔静脉滤器置入术围手术期护理50例临床探讨

目的：探讨50例患者行下腔静脉血栓滤器置入术时实施围术期护理的临床效果,探讨该类手术护理要点。方法对50例下肢深静脉血栓患者采用下腔静脉滤器置入术及溶栓治疗的综合性治疗,对其进行术前、术中、术后护理。结果50例患者手术顺利,阻塞段血管通畅,血液流动,均未发生肺栓塞及滤器移位等并发症及不良反应。结论应用下腔静脉滤器置入术和溶栓治疗对预防肺栓塞并减少并发症是一种较为简单、方便、安全的方法,并且给予术前、术中、术后护理,可有效提高患者生存质量。     

In vivo potentiostatic studies at the electrode tissue interface: filter properties of the monophasic action potential (Ag/AgCl) electrode in living rat heart

The monophasic action potential (Franz) catheter is regarded as the criterion standard for high fidelity recording of a class of physiological signals. However, its signal modulation characteristics have never been reported. Broadband impedance spectroscopy was performed in perfused living rat heart in a three-electrode potentiostatic configuration to determine the filtering characteristics of the MAP and model Ag/AgCl electrode-tissue interfaces. The filter transfer function H(f) (attenuation [dB] vs log(f) [log(Hz)]) was derived for the frequency range 10 Hz-10(6) Hz. As a filter, the MAP interface is characterized by two ranges of filtering behavior. At high frequency the MAP interface is a high-pass filter with passband frequency 54 kHz-549 kHz (median 321 kHz) and with -3 dB cutoff points ranging from 10 kHz to 302 kHz. In this high frequency range the transfer function is characterized by decreasing attenuation per decade. However, in the lower frequency range relevant to physiological signals (the monophasic action potential, 0.1-40 Hz), it is a severely attenuating nondiodic high-pass filter element with an average attenuation of 16.87 dB relative to passband. In this physiological range, rolloff is nonlinear with increasing attenuation per decade. While the MAP electrode and model Ag/AgCl electrodes are high-pass filters with robust transfer functions for high frequency signals in the living heart, the attenuation of signals in a frequency range relevant to in vivo physiological recording imparts extreme attenuation that may distort physiological signals unpredictably. This disadvantage may be mitigated by amplitude scaling to a calibrated pure tone signal within the physiological frequency band to recover a reproducible signal.     

Robust fault detection filter design for a class of neutral‐type neural networks with time‐varying discrete and unbounded distributed delays

This paper is concerned with the problem of robust fault detection filter design for a class of neutral‐type neural networks with time‐varying discrete and unbounded distributed delays. A Luenberger‐type observer is designed for monitoring fault. By introducing an appropriate Lyapunov–Krasovskii functional and by using Jensen's inequality techniques to deal with its derivative, a new sufficient condition for the existence of robust fault detection filter is proposed in the form of LMIs with nonlinear constraints. To solve the nonlinear problem, a cone complementarity linearization algorithm is proposed. In addition, several numerical examples are provided to illustrate the applicability of the proposed approach. Copyright © 2012 John Wiley & Sons, Ltd.     

A prospective long-term study of 220 patients with a retrievable vena cava filter for secondary prevention of venous thromboembolism

BACKGROUND: The immediate and long-term clinical events associated with the placement and removal of a retrievable filter (ALN filter; ALN Implants Chirurgicaux; Ghisonaccia, France) remain largely unknown. METHODS: This was a prospective cohort study with an 18-month follow-up. All consecutive patients scheduled for placement of an ALN filter between April 1999 and June 2005 in the Radiology Department of our hospital were included. RESULTS: During the study period, placement of an ALN filter was indicated in 220 patients (mean age, 70.8 years), who were followed up for a median duration of 338.5 days (range, 1 to 561 days); 148 patients (67.3%) completed the 18-month follow-up. No patients were unavailable for follow-up. All patients had an acute or past venous thromboembolism. Main indications were recurrent venous thromboembolism despite adequate anticoagulation therapy (10.9%), transient bleeding event (21.8%), definitive contraindication for anticoagulant therapy (26.8%), or obligation to stop anticoagulant therapy due to major surgery, major trauma, or invasive procedure (37.7%). Filter insertion was successful in 98.6% of patients and resulted in an immediate complication in 11.8%. The median duration of filter implantation was 166 days (first to third quartiles, 34 to 478 days). Meanwhile, 17.0% (37 of 217 patients) had at least one venous thromboembolic event. Filter retrieval was attempted in 25.3% of patients after a median of 51 days (range, 6 to 352 days); removal was successful at the first attempt in 92.7% of patients. CONCLUSIONS: The filter could be easily inserted and successfully removed up to 1 year after insertion. Its safety and efficacy in preventing pulmonary embolism should be properly assessed in a randomized study.     

用滤除白细胞输血器制备洗涤红细胞的可行性探讨

目的：探讨用滤除白细胞输血器制备洗涤红细胞（WRC）的可行性。方法：用滤除白细胞输血器过滤红细胞后，用0．9％氯化纳溶液冲满血袋，一并在低温离心机中离心，然后把洗涤液挤到0．9％氯化纳溶液袋中，再用新的注射用0．9％氯化纳溶液冲满血袋离心。这样反复3次，既成洗涤红细胞。结果：经检验各项指标符合洗涤红细胞标准，输洗涤红细胞组中的RBC、HGB和HCT均高于输未洗涤红细胞组，经t检验分析，均P〈0．01，差异有统计学意义，且无1例输血反应。结论：用滤除白细胞输血器制备洗涤红细胞方法简便、安全可行，值得基层医院的推广使用。     

声光可调滤光器-近红外主成分分析法快速鉴别银黄口服液和双黄连口服液

目的:以声光可调滤光器(AOTF)-近红外光谱(NIR)技术对银黄口服液和双黄连口服液进行快速鉴别。方法:收集不同生产厂家及不同批号的银黄口服液和双黄连口服液,采集样品的NIR,用主成分分析法分别建立2种口服液的定性分析模型,并以建立的模型相互分析验证。结果:所建立的银黄口服液和双黄连口服液定性分析模型可相互正确予以鉴别。结论:本方法是一种简便、快速、低耗的新型分析技术,可用于2种口服液的快速鉴别。     

作业场所空气中磷酸二丁酯采样方法研究

目的研究作业场所空气中磷酸二丁酯（DBP）的采样监测方法。方法用粉尘采样器采集空气于采样材料中,用溶剂洗脱,取适量洗脱液经硅烷化衍生后作毛细管柱气相色谱分析,研究DBP采样监测的条件。结果采样材料选择过氯乙烯微孔滤膜或丙纶测尘滤膜,使用采样器以5—10L／min流速采集25～50L空气,以乙腈浸泡洗脱滤膜30min最佳,洗脱效率99．0％-101．5％,采样稳定性和溶液稳定性好,7d下降率〈1％,方法的最低检测浓度可达0．005mg／m3,磷酸三丁酯等4种可能干扰物质对DBP的测定不造成影H向。结论该方法适合作业场所空气中DBP的采样监测要求。