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51.
本文介绍了风力发电系统目前存在的技术方案,重点介绍了ABB用于双馈式风力发电系统的变频产品ACS800—67的特性,并对由其构建的发电机测试平台的案例进行了实验分析。  相似文献   
52.
Recently Fourier Transform Infrared (FTIR) spectroscopic imaging has been used as a tool to detect the changes in cellular composition that may reflect the onset of a disease. This approach has been investigated as a mean of monitoring the change of the biochemical composition of cells and providing a diagnostic tool for various human cancers and other diseases. The discrimination between different types of tissue based upon spectroscopic data is often achieved using various multivariate clustering techniques. However, the number of clusters is a common unknown feature for the clustering methods, such as hierarchical cluster analysis, k-means and fuzzy c-means. In this study, we apply a FCM based clustering algorithm to obtain the best number of clusters as given by the minimum validity index value. This often results in an excessive number of clusters being created due to the complexity of this biochemical system. A novel method to automatically merge clusters was developed to try to address this problem. Three lymph node tissue sections were examined to evaluate our new method. These results showed that this approach can merge the clusters which have similar biochemistry. Consequently, the overall algorithm automatically identifies clusters that accurately match the main tissue types that are independently determined by the clinician.  相似文献   
53.
For the purpose of remediation of soils polluted by heavy metals, the use of some strong synthetic chelating agents such as ethylenediaminetetraacetic acid (EDTA) has been proposed. However, EDTA would not be considered as the preferential choice for the remediation of soil polluted with heavy metals like copper because of its nonbiodegradability and permanent residence in the natural environment. In the present work, some novel environmentally benign chelating agents, glucosamine hydrochloride, chito-oligosaccharide and -asparaginic-N,N-diacetic acid (ASDA) were screened to find alternatives to EDTA by investigating the elution of copper from vermiculite with these reagents and comparing their effectiveness with EDTA. The effects of suspension contact time, reagent concentration and equilibrium pH of the solution on the removal of copper were examined. A stoichiometric amount of EDTA can quantitatively remove copper in both acidic and neutral conditions. Chito-oligosaccharide was a slightly less-effective reagent under acidic conditions compared to EDTA, and an amount well in excess of stoichiometry is required to achieve the maximum removal of copper from vermiculite. Glucosamine hydrochloride shows a relatively weak ability for the liberation of copper. The elution behavior of ASDA was equivalent to EDTA in acidic and neutral media. It was concluded that ASDA is the best substitute for EDTA because of its similar high complexing ability and superior biodegradability.  相似文献   
54.
Palladium-doped silica nanocomposites were synthesized via a sol-gel technique combined with a template of Triton X-100 micelle. The freshly prepared sol sample of Pd-doped silica nanocomposites was investigated by TEM. Determined from the TEM image, the sizes of the Pd nanoparticles are narrowly distributed, which are around 30 nm in diameter. The prepared sol solution of the sample was injected into a Tygon Microbore Autoanalysis tubing. After 14 days gelatinization, a transparent porous optical fiber was obtained. The response of the fiber to hydrogen gas was tested by using a fiber-optic spectrometric method. The palladium-doped silica nanocomposite fiber is sensitive upon exposure to hydrogen gas and the response is reversible. This palladium-doped silica nanocomposite fiber can be applied as a new kind of hydrogen gas sensor  相似文献   
55.
根据生产实践 ,结合PLC的技术特点和 385m2 凯利式叶滤机的电气联锁特性 ,阐述了应用PLC技术 ,可进一步提高 385m2 凯利式叶滤机的运转率和自动化水平。  相似文献   
56.
鉴于目前电信的声讯系统中竞争的激烈性,它们急需要提高自身的系统集成度及高可用性,保证以最小的投资获得最丰厚的回报,由此出现了CompactPCI的系列产品,它不仅可以大大提高系统的集成度,同时对于系统的高可用性也进行了充分的考虑。本文将就声讯系统中基于CompactPCI的应用进行分析。  相似文献   
57.
自蔓延高温合成TiNi多孔体合金   总被引:3,自引:0,他引:3  
为了开发新型的生体材料,本文对自蔓延高温合成TiNi多孔体合金——人造骨材料进行了研究。以单质钛粉和镍粉作原料,在氩气保护条件下,采用预热点燃模式和热爆模式制得了不同形态的多孔TiNi形状记忆合金。采用SEM和XRD分析了样品的孔洞特征和相组成,测试了其力学性能,并研究了合成条件参数与样品表面形貌和孔隙状态之间的关系。结果表明,用SHS法制备TiNi多孔体合金是可行的。  相似文献   
58.
Voucher-based reinforcement therapy (VBRT) is an effective drug abuse treatment, but the cost of VBRT rewards has limited its dissemination. Obtaining VBRT incentives through donations may be one way to overcome this barrier. Two direct mail campaigns solicited donations for use in VBRT for pregnant, postpartum, and parenting drug users in Toronto, Ontario, Canada, and in Los Angeles, California. In Toronto, 19% of those contacted over 2 months donated $8,000 ($4,000/month) of goods and services. In Los Angeles, nearly 26% of those contacted over 34 months donated $161,000 ($4,472/month) of goods and services. Maintaining voucher programs by soliciting donations is feasible and sustainable. The methods in this article can serve as a guide for successful donation solicitation campaigns. Donations offer an alternative for obtaining VBRT rewards for substance abuse treatment and may increase its dissemination. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
59.
The change of foot length and width with age has been reported in a few anthropometric studies in the literature. However, the relationship with body height rarely is reported, and the dynamic effect of weightbearing on foot size has not been documented. In this series, 2829 children 3 to 18 years of age of equal gender distribution were included in the study. The foot length and width on weightbearing and nonweightbearing were measured with a special precision electronic caliper. The foot length and width were found to increase linearly from the age of 3 years until 12 years in girls and 15 years in boys. This was followed by a phase during which the increase plateaued. The foot length and width increased significantly on weightbearing at all ages in both genders with a mean of 2.1 to 4.4 mm or 3.1% to 4.8%, respectively. The foot length and width also were found to correlate significantly with the body height in both genders, with a correlation coefficient of 0.96 to 0.98. No significant differences were found between the sizes of the dominant and nondominant foot in either gender.  相似文献   
60.
岩样自然伽玛能谱的数据库管理系统   总被引:3,自引:0,他引:3  
郭余峰  高升 《测井技术》1995,19(1):58-62
本文阐述了岩样自然伽玛能谱数据库管理系统的功能、结构、特点以及它在研究自然伽玛能谱与岩性参数间关系中的应用,为自然伽玛能谱测井的资料解释奠定了理论基础。  相似文献   
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