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81.
韩华  吕健  宋佩茜 《柴油机》2004,(3):44-46
通过分析基于现场总线技术的数字化智能仪表及其网络系统,介绍了数字化智能传感器及执行机构、网桥等网络设备的原理和功能,阐述了把单个分散的测量或控制设备变成网络节点的开放式全分布综合自动化网络系统的特点,并指出其广泛的应用前景。  相似文献   
82.
模拟深海压力对2种低合金钢腐蚀行为的影响   总被引:1,自引:0,他引:1  
刘杰  李相波  王佳 《金属学报》2011,(6):697-705
通过腐蚀失重、电化学测试、锈层分析和微观形貌观察研究了海水压力对不同成分2种低合金钢(X和Y)腐蚀行为的影响.结果表明,X钢更易受到海水压力的影响而被加速腐蚀.深海压力均加速了2种低合金钢的阳极溶解速度;压力对于X钢的氧扩散还原过程影响很小,而海水压力的增加导致Y钢阴极电流密度降低的原因是腐蚀产物直接参与了阴极还原反应...  相似文献   
83.
    
Spinal cord injuries result in the loss of motor and sensory functions controlled by neurons located at the site of the lesion and below. We hypothesized that experimentally enhanced remyelination supports axon preservation and/or growth in the total spinal cord transection in rats. Multifocal demyelination was induced by injection of ethidium bromide (EB), either at the time of transection or twice during transection and at 5 days post-injury. We demonstrated that the number of oligodendrocyte progenitor cells (OPCs) significantly increased 14 days after demyelination. Most OPCs differentiated into mature oligodendrocytes by 60–90 dpi in double-EB-injected rats; however, most axons were remyelinated by Schwann cells. A significant number of axons passed the injury epicenter and entered the distant segments of the spinal cord in the double-EB-injected rats. Moreover, some serotoninergic fibers, not detected in control animals, grew caudally through the injury site. Behavioral tests performed at 60–90 dpi revealed significant improvement in locomotor function recovery in double-EB-injected rats, which was impaired by the blockade of serotonin receptors, confirming the important role of restored serotonergic fibers in functional recovery. Our findings indicate that enhanced remyelination per se, without substantial inhibition of glial scar formation, is an important component of spinal cord injury regeneration.  相似文献   
84.
85.
海洋工程技术强国战略   总被引:2,自引:0,他引:2  
为了推进海洋强国建设,中国工程院于2011年启动了\"中国海洋工程与科技发展战略研究\"重大咨询项目研究。本文从海洋探测、海洋运载、海洋能源、海洋生物资源、海洋环境和海陆关联6个重要工程技术领域开展咨询调查研究,系统分析了海洋工程与科技发展的机遇与战略需求,提出了发展战略和任务。明确提出建设海洋强国,科技必须先行,必须首先建设海洋工程技术强国,建议国家加大海洋工程技术的发展力度,加快实施海洋工程科技创新驱动和现代海洋产业发展推进两大计划。  相似文献   
86.
Aiming at the mode mixture in local wave decomposition(LWD) caused by a noise signal, the original data is preprocessed using the lifting wavelet transformation to suppress abnormal interference of noise and improve the quality of decomposition. It is employed to analyze the vibration signal of rotor rub-impact for extracting the weak impulsive feature. The signal is decomposed into intrinsic mode functions by LWD, then the high-frequency components are analyzed by Hilbert envelop demodulation. The period o...  相似文献   
87.
南秦岭中段亚碱性-碱性岩板块构造环境及岩浆演化   总被引:1,自引:0,他引:1  
从地质特征及室内各种测试入手,对比国外典型地区同类岩石成分特征,运用多种分析方法,对南秦岭中段广泛分布的亚碱性-碱性岩进行深入研究,确定了岩石形成的构造背景、成岩时代,并对岩石多样性原因与演化机理进行了探讨。岩石产于大陆板内张性深大断裂环境,橄榄拉斑玄武岩浆为本区的原始岩浆。  相似文献   
88.
We previously identified the ZNF85 (HPF4) KRAB zinc finger gene, a member of the human ZNF91 family. Here, we show that the ZNF85 gene is highly expressed in normal adult testis, in seminomas, and in the NT2/D1 teratocarcinoma cell line. Immunocytochemical localization of a panel of beta-Gal/ZNF85 fusion proteins revealed that ZNF85 contains at least one nuclear localization signal located in the spacer region connecting the KRAB domain with the zinc finger repeats. Bacterially expressed ZNF85 zinc finger domain bound strongly and exclusively to DNA in vitro in a zinc-dependent manner. The KRAB(A) domain of the ZNF85 protein and of several other members of the ZNF91 family exhibited repressing activity when tested in Gal4 fusion protein assays. The repression was significantly enhanced by the addition of the KRAB (B) domain, whereas further addition of other conserved regions had no effect. The ZNF85 KRAB(A) and (B) domains in vitro bound several nuclear proteins that might constitute critical cofactors for repression.  相似文献   
89.
The association between memory self-efficacy (MSE) and memory performance is highly documented in the literature. However, previous studies have produced inconsistent results, and there is no consensus on the existence of a significant link between these two variables. In order to evaluate whether or not the effect size of the MSE–memory performance relationship in healthy adults is significant and to test several theory-driven moderators, we conducted a meta-analysis of published and unpublished studies. A random-effects model analysis of data from 107 relevant studies (673 effect sizes) indicated a low but significant weighted mean correlation between MSE and memory performance, r = .15, 95% CI [.13, .17]. In addition, the mean effect size was significantly moderated by the way MSE was assessed. Memory performance was more strongly related to concurrent MSE (perceived current ability to perform a given task) than it was to global MSE (perceived usual memory ability in general). Furthermore, we found marginally larger MSE–memory performance correlations when the memory situations used to assess MSE involved familiar stimuli. No effect of the method used to assess global MSE or domain MSE (memory rating vs. performance predictions) was found. The results also show that the resource demands of the memory tasks have a moderator effect, as the MSE–performance correlation is larger with free-recall and cued-recall tasks than it is with recognition tasks. Limitations (generalization issues, moderators not considered) and implications for future research are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
90.
We propose in this paper a programmable band-pass filter based on an array of fully differential transconductance circuits that controls the filter parameters. The signal path does not contain any switch, and fine-tuning of the filter parameters is implemented using programmable capacitors. A digital building block is implemented in the proposed band-pass filter to tune its central frequency as well as its bandwidth. The filter circuit is based on a biquad topology, which is designed and implemented with CMOS 0.18 μm technology. Experimental results show a programming ability of the center frequency between 5.9 and 58 MHz, and the quality factor can be tuned from 0.36 to 10. These features are obtained for a total power consumption of less than 10.5 mW from a single 1.8 V power supply.  相似文献   
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