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31.
噪声是影响雷达接收机灵敏度的重要因素。本文通过讨论雷达接收机噪声的来源,分析并提出了集中降低雷达接收机内部和外部噪声的几种方法,具有一定的实际意义。  相似文献   
32.
As many as 3033 patients with myocardial infarction residing in rural areas were kept under observation. In this population, myocardial reinfarction (MRI) was diagnosed in 411 subjects, with 78.8% having had it for 4 years. Those MRI patients ranging between 51 to 60 years showed the greatest prevalence (44.3%). The ratio of micro- to macrofocal (through-and-through) MRI was 1:3, that of males to females 9:1. Microfocal MRI was commonly associated with a pain-free variant of the disease (23.5%) with low frequency of thromboembolic complications (3.1%). Every fifth patient with macrofocal (through-and-through) renecrosis presented with aneurysm of the heart. In a 10-year and longer follow-up, mortality from MRI was 43.6 percent among patients with macrofocal MRI, while deaths attributable to microfocal MRI were estimated to be 28.9 percent. High mortality rates suggest great severity of illness and low efficacy of the drug therapy adopted.  相似文献   
33.
In order to improver the mould filling ability ,the method for production of thin-walled castings in the traveling magnetic field was applied,The relationship between magnetic field density and input voltage as well as distance was investigated,and the mould filling length of A357 melt has been studied,The electromagnetic forces applied on the melt were also analyzed,The result shows that the mould-filling length of the melt increase rapidly with the increase of magnetic flux density,The mould filling lengths in gypsum upper mould and magnetic material upper mould were compared from the standpoint of application,It demonstrated that the steel upper mould is superior to gypsum mould.  相似文献   
34.
通过对一次爆炸量为65t的硐室大爆破地震效应的实测,得出了一些有价值的结论。  相似文献   
35.
工程制图精品课程建设的探索与实践   总被引:2,自引:0,他引:2  
论述了为培养高素质人才,全面提升高等教育教学质量,必须积极推进和实施工程制图精品课程建设及其建设目标。从加强师资队伍建设、教学内容与课程体系、教学方法与手段、教材与教学资源、实践教学、教学效果等方面探索了工程制图的教学改革和课程建设实践。总结了制图精品课程建设的特色和所取得的成果,并提出了进一步应探讨和研究的一些问题。  相似文献   
36.
The purpose of the study was to describe how three generations of mothers have reacted to their pregnancies and deliveries and also how they feel about their maternity. Furthermore, the purpose was to illustrate the transfer of knowledge from one generation to another. Interviews have been made with three triads of generations, in all nine mothers. A phenomenological-hermeneutic onset has been chosen in order to analyse the narratives of the mothers. In the structural analyses the following themes came to hand: positive experiences/feelings, negative experiences/feelings, internal and external network and knowledge. The life-experiences of the maternity of the mothers were chiefly positive while experiences from pregnancy and childbirth were positive as well as negative. The knowledge of the mothers regarding childbirth and the bringing up of children were mostly conveyed in the everyday-contact during their early years, amongst mother-daughter-granddaughter. For the feeling of a successful experience during pregnancy, delivery and maternity, the internal network as well as the external turned out to be of great importance. In order to even better be able to provide for the needs of the expectant mothers or of those who have recently become mothers, an individual planning of care of both in- and out-patients within maternity- and childwelfare can be valuable.  相似文献   
37.
基于FPGA的位同步信号提取   总被引:1,自引:0,他引:1  
同步是通信系统中一个非常重要的实际问题。在同步通信系统中,同步系统性能的降低会导致通信系统性能的降低,甚至使通信系统不能正常工作。因此,同步是信息能够正确可靠地进行传输的前提。介绍一种基于FPGA的锁相环位同步提取技术的原理,并用VHDL语言编程实现,在QuartusⅡ下编译仿真通过,给出仿真波形图。经分析该设计稳定可靠,且能够完成要求。  相似文献   
38.
Based on a comprehensive analysis of findings from examination and surgical treatment of 196 patients with bleeding pyloroduodenal ulcers, it was found out that patients with concurrent helicobacteriosis of the stomach are prone to more unfavourable course of their illness, which fact is evidenced by a greater loss of blood and higher risk for bleeding recurrences. A classification is proposed by the authors, taking advantage of the data from endoscopic, microscopic and immunoenzymatic techniques, with the purpose of providing an assessment of degree of severity of helicobacteriosis of the stomach.  相似文献   
39.
STUDY OBJECTIVE: To validate the utility of a previously reported 3-point limited sampling model (LSM) for determining etoposide area under the curve to infinity (AUC(infinity)). DESIGN: Secondary analysis of data from two clinical trials of etoposide. SETTING: University medical center clinical research center. PATIENTS: Thirty-four patients with different malignancies. INTERVENTIONS: Etoposide was administered as a 2-hour infusion to 34 patients. Serial plasma samples were drawn over 24 hours after the infusion and analyzed for etoposide by high-performance liquid chromatography. MEASUREMENTS AND MAIN RESULTS: The 3-point LSM AUC was compared with a 14-point actual AUC calculated by the linear trapezoidal rule. Actual and predicted AUC(infinity) by the LSM were highly correlated (r=0.97, p<0.0001). The LSM predictions had a mean absolute error of 10.9% (95% CI -14.1, -5.3) and a mean error of -9.7% (95% CI 6.9, 14.9). Nine patients with poor AUC(infinity) estimations by the LSM (error > 12%) tended to have abnormally low or high peak concentrations. CONCLUSION: Our findings suggest the development of more robust LSM using other techniques, such as pharmacostatistical models, that can accommodate a greater degree of pharmacokinetic variability.  相似文献   
40.
对维吾尔药材数据仓库构建中各阶段的模型进行设计。信息包图进行概念模型设计。根据信息包图生成逻辑模型的星形图,进而实现物理模型设计。根据三级模型的设计,利用MicrosoftSQLServer2005创建维吾尔药l材数据仓库维度表和事实表,为方便用户决策分析,利用SQLServerBusinessIntelligenceDevelopmentStudio组件创建了维吾尔药材数据立方体。  相似文献   
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