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71.
本文对四维空间直线绕平面旋转的轨迹进行一投详尽的讨论,按照直线与“轴平面”的相对位置不同,该旋转轨迹分别为圆柱面、圆锥面和单叶回转双曲面,并认为这些回转曲面的轴线是过该直线的与“轴平面”垂直的超平面与“轴平面”的交线。 相似文献
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Li Xi Zuoyan Peng Wei Fan Kui Guo Gu Jianmin Muyu Zhao Wu Guoqiang 《Materials Science and Engineering: B》1996,40(2-3):147-152
SrMgxTi1 - xO3 nanocrystals (x = 0.1–0.6) were synthesized by the stearic acid gel method. Powder samples were characterized by X-ray diffraction and X-ray photoelectron (XP) spectroscopy. The results showed that the lattice parameter a and the O 1s XP spectrum changed not only with the Mg content x but also with the grain size d of the samples. The conductivity of a thick film specimen fabricated on an aluminium oxide wafer was investigated in a nitrogen—oxygen atmosphere. 相似文献
74.
步进式加热炉炉温优化设定模型及软件开发 总被引:1,自引:0,他引:1
针对线材厂步进式加热炉实际工况,提出了基于经验规则的炉温优化设定模型和在线自学习获取知识的思想,并以炉温优化设定模型为核心,开发出加热炉计算机控制系统的优化运行软件。 相似文献
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本文首先对ATM的背景作了一个简单的介绍,接着阐述了ATM和ATM交换机的主要原理和技术,然后从硬件系结构的角度具体地分析了一种实验ATM交换机是怎样ATM技术的详细方法。 相似文献
78.
BACKGROUND: In the outpatient use of tuberculin skin testing (purified protein derivative [PPD]), it is at times inconvenient to have a patient revisit for interpretation. Therefore, we assessed patients' ability to self-interpret these test results. METHODS: In keeping with prior custom, patients were seen by an experienced nurse, who performed skin testing with PPD intermediate strength as well as mumps and Candida anergy control tests in some cases, and explained the procedure. The patients were asked to return 48 to 72 h later, at which time one of the researchers recorded their test interpretations before they were again evaluated by the nurse. RESULTS: Sixty-eight patients were studied, of whom 59 returned at appropriate interval. Eighteen patients had a positive PPD test reaction of 10 to 20 mm induration, which only one patient correctly identified as a positive test result. However, positive anergy control tests were correctly interpreted in 10 of 27 cases. CONCLUSION: The small number of positive PPD test result recognition by these patients may be partially attributed to their lack of education, as well as foreign birth and denial of illness. PPD results should be checked by an experienced professional. 相似文献
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A simple and accurate measurement of intraabdominal pressure is essential to predict a successful closure of defects in omphalocele and gastroschisis. Intravesical pressure (IVP) is a close estimation of intraabdominal pressure and can be measured safely by placing a catheter in the urinary bladder during surgery. Three neonates with gastroschisis and four with omphalocele were studied. Pressure-related complications such as ascites leakage, ventral hernia, impaired venous return of the lower extremities, and oliguria developed only in the patients with IVP > 20 mmHg after fascial closure. Prolonged hospitalization, ventilation support and intensive care were required for these patients. 相似文献