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181.
182.
瑞典Laholm沼气厂的运行实践 总被引:1,自引:0,他引:1
瑞典沼气的总产量约为1400GW·h,约有60%产自200多家市政污水处理厂的污泥消化池,垃圾填埋场的产量占30%,剩余的10%主要来源于工业废水处理厂和混合消化厂。一般情况下,沼气用作热源和发电,也可以作为汽车燃料。有机废物转化成沼气的同时还产生了消化残余物,可用作生物肥料。在瑞典有机废物填埋要课以重税,并且自2005年开始该国已严禁有机物的填埋处理,所以人们逐渐开始了对有机物混合消化的重视和研究。目前瑞典约有10家沼气厂利用厌氧消化处理收集来的各种有机废料,总处理能力>20×104t/a。多数沼气厂将牲畜粪便作为主要原料,再辅以其他… 相似文献
183.
184.
基于概念网络的文本信息监控技术 总被引:1,自引:0,他引:1
由于网上信息的迅速增长,文本信息监控已经成为网上信息管理中的热点研究课题。本文在模糊集和语义网络的理论基础上,构建了模糊值动态约束性概念网络,介绍了该概念网络的基本构建方法,并提出了基于概念网络的文本分析算法。 相似文献
185.
An analytical solution of the dependence of the field distribution on the three-spatial coordinates in a permanent-magnet (PM) disk machine is obtained using the concept of magnetic charge and the method of images. A good correlation between the analytical solution and experimental data validates the method described. It is further indicated how this method can be extended to more complex problems. It is applicable to other PM machines, such as permanent-magnet linear synchronous motors.<> 相似文献
186.
Yourong XU Deying WANG Qi JIN Yijian ZHOU Shanghai University of Science Technology Shanghai ChinaFan HU Chao LIU Iron Steel Research Institute of Baoshan Iron Steel Complex Shanghai China 《材料科学技术学报》1993,9(4):279-282
By means of electron probe(EPMA),scanning electron microscope(SEM),and optical microscope(QM),the diffusion behaviour on the Fe-Cu interface of copper brazed double-wall steel tubes andthe microstructure of the diffusion layer have been investigated.There are three kinds of metallurgicalbonds between copper plating layer and steel substrate: (1)the Cu diffusing into steel substratealong grain boundary of ferrite;(2)the Cu diffusion into grain bulk of ferrite: (3)the Fe diffusing intoCu layer.The copper brazed double-wall steel tubes are formed by the combination of the diffusionsmentioned above and this is the reason for excellent mechanical and technological properties of thecopper brazed double-wall steel tubes. 相似文献
187.
Gao Chao 《电子科学学刊(英文版)》2005,22(5):558-563
This letter puts forward a method of modeling for the steady-state and small signal dynamic analysis on PWM, quasi-resonant and series/(parallel) resonant switching converters based on pulse-waveform integral approach. As an example, PWM and quasi-resonant converters are used to discuss the principle of the approach. The results are compared with those in the relative literatures. Computer aided analysis are made to confirm the correctness. 相似文献
188.
An efficient approach for calculating the dispersions of photonic-crystal fibers: design of the nearly zero ultra-flattened dispersion 总被引:1,自引:0,他引:1
Tzong-Lin Wu Chia-Hsin Chao 《Lightwave Technology, Journal of》2005,23(6):2055-2061
A novel and efficient approach is proposed to calculate the dispersions of the guided modes of the photonic-crystal fibers (PCFs). Based on the vector boundary-element method (VBEM), the surface integral equations for the first and second derivatives of the propagation constants with respect to the wavelength are explicitly derived. Compared with the three-point finite-difference approach, which needs to solve and search three effective indexes near the interested wavelength, this approach can determine the dispersions of the PCFs by only solving one effective index at this wavelength based on the derived formulations. This novel approach saves over 60% computing time without losing the accuracy. Based on this approach, a novel four-ring PCF is designed by optimizing only three geometrical parameters to achieve the nearly zero ultra-flattened dispersion property. Compared with previously presented dispersion-flattened PCFs, the design procedure for the four-ring structure could be more efficient and easier because relatively lesser parameters need to be optimized. 相似文献
189.
E Aida Pea‐Ramos Youling L Xiong Guillermo E Arteaga 《Journal of the science of food and agriculture》2004,84(14):1908-1918
Whey protein isolate (WPI) was hydrolysed for 1 h using Alcalase, Protamex and Flavourzyme. Native WPI, hydrolysed WPI and two commercial WPI hydrolysates were subjected to fractionation by size exclusion chromatography. Antioxidant activity of WPI fractions was measured with a liposome‐oxidising system (50 µM FeCl3/0.1 µM ascorbate, pH 7.0). Lipid oxidation was measured as thiobarbituric acid‐reactive substances (TBARS). Gel electrophoresis and amino acid analysis were run to identify the peptide composition. The influence of amino acid composition on antioxidant activity was evaluated using multivariate analysis methods (correlation analysis, principal component analysis, multiple linear regression and discriminant analysis). TBARS assays indicated the presence of antioxidant activity in all protein fractions, including non‐hydrolysed WPI. For native and hydrolysed WPI samples the first fraction (> 45 kDa) showed a higher TBARS inhibition effect (24–27%) when compared with lower‐molecular‐weight fractions and hydrolysate mixtures. In contrast, for commercial WPI hydrolysates a higher inhibitory effect was found in most of the lower‐molecular‐weight fractions (30–55%). The ability of WPI fractions to delay lipid oxidation was found to be related to the prevalence of histidine and hydrophobic amino acids. Copyright © 2004 Society of Chemical Industry 相似文献
190.