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991.
PECVD方法用于梯度薄膜材料的研究 总被引:3,自引:1,他引:2
本文研究了PECVD方法制备Si-O-M系梯度薄膜材料,并运用计算机控制技术成功地制备了涂层折射率随膜深成正弦波形式连续变化的Rugate单通带滤波器样品。结果表明,采用PECVD方法可以制备性能上乘、结构复杂的梯度薄膜材料,PECVD方法在研究、开发高级光学涂层领域有着宽广的应用前景。 相似文献
992.
993.
There is agreement on the clinical diagnostic criteria for acute inflammatory demyelinating polyneuropathy (AIDP/GBS) however, there is lack of consensus for detection of demyelination. In order to critically evaluate the prevailing criteria, sixty-six patients who fulfilled NINCDS criteria and had typical features of GBS were studied for electrophysiological abnormalities of peripheral nerves by using standard methods (median, common peroneal, sural and ulnar) between 1 to 12 weeks after the onset of symptoms. The commonest abnormality on motor nerve conduction study was prolonged distal latency (75%-83%) followed by reduction in CMAP amplitude (63%-82%), decreased velocity (48%-62%), conduction block (17%-39%) and f-wave abnormalities (37.8%-59%). Sensory conduction abnormalities were detected in over 20% of median, 25% of ulnar and 33% of sural nerves. All the patients had abnormality of at least two motor conduction parameters in one nerve when values beyond 2 SD of the mean were considered abnormal and over 70% of patients had three abnormalities in two nerves or two abnormalities in three nerves. Comparison with the prevailing criteria for demyelination revealed that the number of patients fulfilling them varied widely: Albers et al. (1985): 74.2%, Albers et al. (1989): 40.9% and Cornblath: 30.3%. We believe that the current criteria for detection of demyelination in acute neuropathy are too strict, underestimate the underlying pathology in GBS and need reassessment. 相似文献
994.
From 1970 to 1992 a total of 63 patients underwent operation for ampullary tumor: 40 pancreatoduodenectomies (PDs), 3 total PDs, 8 ampullectomies, and 12 bypass or exploratory laparotomies. The resectability rate was 68%. There were 9 benign tumors, 1 anaplastic tumor, and 53 adenocarcinomas. According to Martin's classification, there were 7 stage I, 11 stage II, 14 stage III, and 21 stage IV tumors. All patients with stage I, II, and III tumors underwent resection. Patients with stage IV tumors had either resection (n = 11) or bypass (n = 10). The mean duration of hospital stay was 20.6 days. Operative mortality was 12.7% for the whole series and 7.5% after PD (2.5% for the last 10 years). Overall survival was 40% at 5 years (85% for stage I, 65% for stage II, 44% for stage III, and 8% for stage IV). Survival was better for stages I, II, and III after PD than after ampullectomy. For stage IV patients survival was 70% after PD versus 20% after bypass at 1 year and 25% versus 0% after 2 years. In our opinion, PD should be proposed even for benign lesions because two of our patients had to undergo repeat operation (PD) 4 and 22 years later, respectively, for stage IV disease. PD is our choice for all tumors of the ampulla. 相似文献
995.
饮用水氯化中氯仿形成的动力学模式 总被引:12,自引:0,他引:12
以黄腐酸(FA)为卤仿前驱物质,分别测定不同投氯量、TOC水平、温度以及pH值对CHCl3形成速率的影响,确定出CHCl3形成的动力学模式。该模式可用于预测投氯后的管网水中CHCl3的形成量,以便采取必要措施保证饮用水符合国家规定CHCl3〈60μg/L的标准。 相似文献
996.
A closed-form physical model is reported for VLSI bipolar devices considering energy transport. Based on the model, for a base width of 810 Å, the bipolar device, biased at Vcb=2 V, has a peak electron temperature of over 700 K, which results in a 5% reduction in the collector current 相似文献
997.
Gain-enhanced compact broadband microstrip antenna 总被引:1,自引:0,他引:1
Chih-Yu Huang Jian-Yi Wu Cheng-Fu Yang Kin-Lu Wong 《Electronics letters》1998,34(2):138-139
With the loading of a high-permittivity superstrate layer and a 1 Ω chip resistor, a compact rectangular microstrip antenna with enhanced gain and wider bandwidth can be implemented. With the antenna size reduced to be ~6% that of a conventional patch antenna, the proposed structure can have an operating bandwidth of more than six times that of a conventional patch antenna, with an almost equal antenna gain level. Details of the experimental results are presented and discussed 相似文献
998.
999.
郭瑞璜 《消防技术与产品信息》2002,(3):60-64
关东大地震火灾 ,可谓 2 0世纪世界上最大的地震火灾 ,造成的人员伤亡和财产损失确实称得上前所未有。最近 ,有关方面正在吸取阪神大地震的教训 ,实施各种防灾对策。笔者以为 ,只有把确实存在着严重程度远远超过阪神大地震的灾害这件事 ,牢牢铭刻在头脑中 ,理顺对付罕见的大灾害的基本思路 ,才能从总体上全面地研究灾害对策。而且 ,关东大地震火灾的有些问题至今尚未研究清楚 ,笔者切望彻底搞清这些问题 ,以促进火灾工程学的发展。有鉴于此 ,有必要对关东大地震火灾这一历史性大灾害作一番回顾。1.关东大地震的调查情况关东大地震发生在 192… 相似文献
1000.
下套管作业时,套管螺纹联接质量的好坏直接影响着油井寿命,因此有必要研制一种套管动力钳转矩监测系统。以目前国内常用的TQ-20型套管动力钳为例,介绍了一种与之相配套的套管钳转矩监测系统的功能特点,测试原理,结构设计,并对实测各类紧扣曲线进行了分析。该系统采用主从机结构,主机为工业控制微机,从机为单片机系统,主从机采用远距离通信传输,大大地改善了工业控制微机的工况条件。该系统实现无人监控、自动记录、绘 相似文献