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A.L. Pan H.G. ZhengZ.P. Yang F.X. Liu Z.J. Ding Y.T. Qian 《Materials Research Bulletin》2003,38(5):789-796
Small Ag particles or clusters dispersed mesoporous SiO2 composite films were prepared by a new method: First the matrix SiO2 films were prepared by sol-gel process combined with the dip-coating technique, then they were soaked in AgNO3 solutions followed by irradiation of γ-ray at room temperature and in ambient pressure. The structures of these films were examined by X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), and optical absorption spectroscopy. It has been shown that the Ag particles grown within the porous SiO2 films are very small, and they are isolated and dispersed from each other with very narrow size distributions. With increasing the soaking concentration and an additional annealing, an opposite peakshift effect of the surface plasmon resonance (SPR) was observed in the optical absorption measurements. 相似文献
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用保角变换法对共面波导金属厚度效应进行了理论分析,编制了相应的计算机程序,给出了数值解,并对此进行了多元曲线拟合,导出了考虑金属厚度后的形状比k、有效介电常数、特征阻抗、损耗的闭定表达式。用此修正表达式求得特征阻抗及损耗的数值解,并与K.C.格普塔的修正值及实验测量值进行了详细比较,结果表明此修正公式与实验值相符较好。 相似文献
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BACKGROUND: The enterococci have become important nosocomial pathogens. They can cause multiple site infections and enterococcal bacteremia becomes more frequently associated with a high mortality rate. Previous studies of enterococcal bacteremia showed a variety of results. To establish the significance and importance of enterococci as nosocomial pathogens in this hospital, to characterize their clinical pictures and to search for the risk factors for mortality, this retrospective study was performed. METHODS: There were 208 cases of enterococcal bacteremia which occurred from 1988 to 1992. Twenty-seven cases had no medical charts, dismissing possibility of evaluation. Finally, 181 cases of enterococcal bacteremia were analysed. RESULTS: One hundred and eighteen episodes were nosocomial infections. Polymicrobial bacteremia occurred in 68.5% of the patients and the most common co-isolate was Pseudomonas aeruginosa. Those patients (78.5%) with underlying diseases and malignancies were the most common underlying problems. The portal of entry could be found in 69.6 percent of patients, with the gastrointestinal tract the most common sources. Antimicrobial susceptibility testing showed high gentamicin resistance rate (89.5%), and ampicillin still had about 80 percent sensitivity rate. The group who received specific antibiotic therapy for enterococcus showed lower mortality (36.4% versus 47.6%). Only one case had infective endocarditis. Forty-nine patients suffered from septic shock, the cause of 30 deaths. Totally 75 patients died during hospitalization. Besides sepsis, another major cause of death was their underlying diseases itself. CONCLUSIONS: Enterococci have no doubt become important nosocomial pathogens and enterococcal bacteremia were associated with high mortality, especially in elderly patients with underlying diseases such as malignancy or diabetes. When clinically dealing with sepsis from the gastrointestinal or biliary tract, especially when previous cephalosporins therapy showed no response, the possibility of enterococcal bacteremia should always be considered. 相似文献
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NF Saba JD Sweeney LC Penn JC Lawton RL Yankee CH Huang MS Schanfield 《Canadian Metallurgical Quarterly》1997,37(3):321-324
PURPOSE: We report a case of postoperative reparalysis in the recovery room, following nebulized epinephrine. The patient was pharmacologically reversed with edrophonium after paralysis with rocuronium. CLINICAL FINDINGS: A 12-yr-old girl developed postoperative reparalysis following the intraoperative administration of rocuronium. A total of 0.92 mg.kg-1 rocuronium was administered. After surgery, pharmacological reversal was achieved with 20 mg edrophonium with 0.15 mg atropine sulfate iv 35 min after the last administration of rocuronium. Muscular relaxation was monitored using an ulnar peripheral nerve stimulator (PNS). After reversal, a full train-of-four and sustained tetanus at 50 Hz were present. In the recovery room, following nebulized epinephrine, the patient became apneic. The patient was paralyzed and an ulnar PNS demonstrated only one faint twitch. The paralysis was reversed with 1.5 mg neostigmine with 0.3 mg glycopyrrolate. CONCLUSION: Postoperative reparalysis following rocuronium may be a cause of postoperative respiratory distress. The definitive diagnosis is made using PNS and observing the response to pharmacological reversal. Nebulized epinephrine may have a previously undescribed role in the development of postoperative reparalysis. 相似文献
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大规模数据库中的知识获取 总被引:1,自引:0,他引:1
一、前言数据是知识的潭泉,拥有大量的数据与拥有许多有用的知识完全是两回事.为了有效地利用大量的公共数据,必须更好地理解这些数据,并从其中快速、准确地发现知识.这里所说的知识是指大量数据中存在的规律性(r egularity)或不同属性值之间所存在的[I F THEN〕规则.将所获取的知识附加于仅由事实数据(fact data)构成的传统数据库上,既可强化数据库的查询能力,又可给数据库提供推理能力, 相似文献
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