虚拟技术在固体冲压发动机地面试验系统中的应用     

李进贤  岳春国  侯晓  冯喜平  唐金兰 《实验技术与管理》2009,26(1)

在深入分析固体火箭冲压发动机试验系统的组成和参数特点的基础上,提出了发动机温度、压力、流量及其推力测量的总体方案和进气模拟总体控制方案.利用LabVIEW测量与自动化软件开发平台,开发了适用固体火箭冲压发动机试验推力、压力、流量和温度测量的数据采集软件.基于PID控制器开发了温度、压力调节控制软件,能根据试验要求自动地调节空气和燃油的流量,能实现进气温度、压力模拟和试验过程控制.开发了通用的温度、压力、流量、推力等物理量标定程序,并建立了相应的试验数据库.  相似文献   

聚氨酯泡沫塑料应力-应变关系的试验与参数识别     

赵培  侯之超  何乐  胡德贵 《实验技术与管理》2009,26(1)

介绍了获得聚氨酯泡沫塑料压缩状态下应力-应变关系的恒速加、卸载试验与参数识别的基本方法与过程.针对2种不同密度的聚氮酯泡沫塑料,以不同的速率做了恒速加、卸载试验,以遗传积分模型为例介绍了利用恒速加、卸载试验识别模型参数的方法,提出了进行试验数据预处理的线性插值法.  相似文献   

Relationships between endothelial nitric oxide synthase gene polymorphisms and osteoporosis in postmenopausal women     

Shun-zhi Liu  Hong Yan  Wei-kun Hou  Peng Xu  Juan Tian  Li-fang Tian  Bo-feng Zhu  Jie Ma  She-min Lu 《Journal of Zhejiang University. Science. B》2009,10(8):609-618

Objective: To investigate the relationships between endothelial nitric oxide synthases (eNOS) G894T and 27 bp-variable number tandem repeat (VNTR) gene polymorphisms and osteoporosis in the postmenopausal women of Chinese Han nationality. Methods: In the present study, 281 postmenopausal women from Xi'an urban area in West China were recruited, and divided into osteoporosis, osteopenia, and normal groups according to the diagnostic criteria of osteoporosis proposed by World Health Organization (WHO). The bone mineral density (BMD) values of lumbar vertebrae and left hips were determined by QDR-2000 dual energy X-ray absorptiometry. Blood samples were tested for plasma biochemical indicators including testosterone, estradiol, calcitonin, osteocalcin, and procollagen type I amino-terminal propeptide by enzyme-linked immunosorbent assay (ELISA), tartrate-resistant acid phosphatase by spectrophotometric method, and the content of nitric oxide by Griess method. Genome DNA was extracted from whole blood, and G894T polymorphism of eNOS gene was analyzed by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method and 27 bp-VNTR polymorphism of eNOS gene was genotyped by PCR method. Then the relationships between genotypes and biochemical indicators, genotypes and osteoporosis, and haplotypes and osteoporosis were analyzed. Results: The average BMD values of the femoral neck, ward's triangle and lumbar vertebrae 1～4 (L1～L4) in the subjects with T/T genotype in eNOS G894T locus were significantly higher than those in the subjects with G/T and G/G genotypes (P<0.05). The average BMD of the femoral neck in the subjects with a/a genotype of eNOS 27 bp-VNTR locus was evidently higher than that in the subjects with b/b genotype (P<0.05). The plasma testosterone and osteocalcin concentrations in the subjects of eNOS G894T G/T genotype were evidently higher than those in the subjects of other genotypes (P<0.05); the plasma estradiol concentration in the subjects of eNOS 27 bp-VNTR a/a genotype was obviously higher than that in the subjects of b/b genotype (P<0.01). eNOS G/G homozygous frequencies in osteoporosis women, osteopenia women, and normal women were 85.37%, 76.38%, and 83.87%, respectively (P＞0.05). 0% osteoporosis woman, 0.79% osteopenia women, and 3.23% normal women were eNOS a/a homozygous (P<0.05). The frequencies of eNOS 27 bp-VNTR a allele were 5.33% in the osteoporosis group, 10.24% in the osteopenia group, and 16.13% in the normal group (P<0.05, odds ratio (OR)=0.29, 95% confidence interval (CI)=0.11～0.77), suggesting that a/a genotype and a allele might have protective effects on osteoporosis. The haplotype analysis showed that G-b was 87.7% (214/244) in the osteoporosis group (P<0.05, OR=2AS, 95% CI=1.18～5.18). G-a was 5.3% (13/244) in the osteoporosis group (P<0.05, OR=0.29, 95% CI=0.11～0.77). G-b was a risk factor for osteoporosis, and G-a a protective factor. Conclusion: eNOS G894T G/T genotype influenced the plasma testosterone and osteocalcin concentrations, and T/T genotype influenced BMD. eNOS 27 bp-VNTR a/a genotype increased plasma estradiol concentration to have a protective effect on osteoporosis.  相似文献   

机械设计制造及其自动化专业建设的实践与探索   总被引：4，自引：0，他引：4  

孙全平  刘远伟  侯志伟  蒋同洋 《高教论坛》2005,(6):117-118

本文针对大众化高等教育的办学思想和人才培养要求,对机械设计制造及其自动化专业建设的深层次问题进行了研究与探索,提出了具体的建设思路,取得了阶段性的成果.  相似文献   

Multi-product total cost functions for higher education: The case of Chinese research universities     

Hou Longlong  Li Fengliang  Min Weifang 《Economics of Education Review》2009

This paper empirically investigates the economies of scale and economies of scope for the Chinese research universities by employing the flexible fixed cost quadratic (FFCQ) function. The empirical results show that both economies of scale and economies of scope exist in the Chinese higher education system and support the commonly belief that universities as multi-product organizations.  相似文献   

情报价值的定量化研究综述     

侯丽  李娟 《情报理论与实践》2009,32(4)

情报研究是一项极其复杂的知识活动,对情报价值的定量化研究具有一定的难度,本文较为全面地阐述了国内外情报价值定量化研究的现状和热点,重点对情报价值量化理论与量化方法进行全面综述.  相似文献   

基于知识图谱的国际科学计量学研究前沿计量分析   总被引：10，自引：0，他引：10       下载免费PDF全文

侯海燕  刘则渊  栾春娟 《科研管理》2009,30(1):164-170

摘要：通过绘制科学计量学研究前沿知识图谱,界定出七大国际科学计量学研究前沿领域：1、引文理论、科学交流、基础科研评价;2、科学知识图谱理论与方法、网络计量学;3、科学技术合作;4、科学计量学经典概率分布、文献计量学定律、信息计量学;5、科学计量学指标与国家科研绩效评价;6、知识的新产品--科技动力学;7、科学与技术的关系。其中前沿领域1、2、4属于理论与方法研究领域,而前沿领域3、5、6、7属于应用研究领域。经过比较发现科学计量学更加侧重于理论与方法研究。  相似文献   

图书馆产业运作模式探讨   总被引：1，自引：0，他引：1  

侯国柱 《情报探索》2009,(5):21-22

从可持续发展的角度,论述了图书馆开展产业运作的必要性以及产业运作的模式和需要处理好的几种关系。  相似文献   

西藏城镇居民消费结构状况分析     

徐爱燕  刘天平  侯霞 《科技广场》2009,(12):103-106

随着经济水平的提高,人们的收入及消费结构都在不断的发生变化.本文分析了西藏城镇居民消费结构的变化及发展趋势,并通过计算西藏城镇居民的平均消费倾向、对比高收入群体和低收入群体的可支配收入,发现西藏城镇内需不足,收入差距不断增大,这些都严重阻碍了消费结构的升级.文章最后对造成这两种现象的原因进行了总结,提出了克服这两大阻碍因素的政策建议.  相似文献   

基于语音识别的智能防盗报警系统设计     

侯昭广 《中国科技信息》2009,(19):143-144

为了使防盗报警系统具有智能化和增加安全性,该系统利用凌阳16位单片机SPCE061A芯片对特定人短语音具有较好的语音识别能力,并且采用反混叠滤波、预加重和动态时间规整技术,使系统具有防干扰能力强,成本低,语音识别好等优点,从大量实验知道,该系统防盗报警的准确率和可靠性都较好。  相似文献