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81.
文章提出配电接线系统综合布线思想,完成了系统主要部件的功能设计和电气设计。该接线系统与武汉供电公司多用户电能集中检测控制器配合使用,较好地解决了防窃电和消除配电接线火灾隐患难题。接线系统施工方便,降低了工程造价。 相似文献
82.
83.
This study seeks to improve the geometrical distribution of bricks to optimise the equivalent thermal transmittance of a wall built of Termoarcilla® ECO 29 voided clay bricks, using calculations according to Spanish UNE [1], AENOR [10], European EN [6], [7], [8] and [9] and international ISO [11] and [12] standards.The objective is to study improvements in the wall's thermal conductivity, always remembering the limitations imposed by the manufacturing process. Simulations are made using a finite elements application [14].It is concluded that, within the possibilities allowed by the manufacturing process, with non-rectangular voids the heat flux has to cross a higher number of voids, which improves its thermal properties. A rhomboid layout of voids with the longer diagonal at right angles to the heat flux is the best internal void layout. If the internal perforations are also extended to the end of the tongue and groove, the direct thermal bridge in this type of brick is broken.Finally, a 290 mm wide brick with 25 rows is obtained with the geometrical properties described above which shows an improvement of almost 16% over the original ECO 29 brick, performing well in all climatic areas of Spain, with a full-bed mortar joint 30 mm thick. 相似文献
84.
The thermal conductivities of solid materials were measured by a G-M cryo-cooler based apparatus in the temperature range of 2.6–21.0 K. The performance of this apparatus was verified by measuring the thermal conductivity of 304-stainless steel, and good reproducibility as well as accuracy was shown when compared with the certified values. The thermal conductivities of EC1017 and Stycast2850FT and a composite material were measured. Similar behavior to amorphous materials was shown for EC1017 and Stycast2850FT in that there was an apparent plateau, which could be ascribed to a very lower crystallinity of epoxy. An equivalent model was proposed to predict the thermal conductivity of the composite material. 相似文献
85.
Silver coated vapor-grown-carbon nanofibers for effective reinforcement of polypropylene-polyaniline
This work utilizes a modification of our process of polymer entrapment in silver to deposit silver crystals on carbon nanofibers at different relative concentrations. The experimental procedure and the characteristics of silver coated nanofibers are presented in detail. The resulting nanofibers are then melt-mixed with a polypropylene-polyaniline blend to form a uniform dispersion that is finally extruded to produce continuous monofilament composites of high axial orientation. The reinforcement effect of the silver coated nanofibers, manifested in the mechanical properties of the monofilament composites, is 3-5 folds higher than that of the pristine nanofibers due to the improved stress transfer mechanism of the former. Additional attractive properties of the new system may result from its anisotropic crystalline structure, enhanced thermal stability, potential electrical conductivity and antibacterial behavior. 相似文献
86.
Five different compositions of K x V 2 O 5 ·nH 2 O(where x=0.00,0.0017,0.0049,0.0064 and 0.0091 mol) were prepared by the sol-gel process.Electrical conductivity and thermoelectric power were measured parallel to the substrate surface in the temperature range of 300-480 K.The electrical conductivity showed that all samples were semiconductors and that conductivity increased with increasing K content.The conductivity of the present system was primarily determined by hopping carrier mobility.The carrier density was evaluated as well.The conduction was confirmed to obey non-adiabatic small polaron hopping.The thermoelectric power or Seebeck effect,increased with increasing K ions content.The results obtained indicated that an n-type semiconducting behavior within the temperature range was investigated. 相似文献
87.
采用火花源原子发射光谱分析测定电工钢中超低C,研究试样制备方法、Ar纯度和压力等条件对分析结果的影响,并对工作曲线进行了优化,实现了一次分析同时测定电工钢的多种元素,满足炉前和精炼在线分析的要求。 相似文献
88.
《国际生产研究杂志》2012,50(17):4793-4805
The purpose of this paper is to investigate the customer satisfaction of power users using the Analytic Hierarchy Process (AHP) method. The objective is to safeguard the interests of electricity consumers and to increase the profitability of the energy distributer. Compared with previous work based on customer questionnaires describing the level of satisfaction, and where the solution is judged to be random due to the low significance of the studied sample, this paper develops a novel strategy. It is based on a global and transparent process regarding the reliability and economic criteria associated with alternatives, highlighting technical and organisational measures taken by the enterprise. The importance of reliability and economic criteria to the alternatives is processed using reliability indices analysis and cost benefit analysis methods. To analyse the customer's reactions to the decisions taken by the system's manager, and to validate the obtained results using the AHP method, we introduce economic criteria often used in the case of an uncertain future. The obtained results indicate the advantage of investment to improve customer satisfaction and enterprise profitability. It is also shown that reliability criteria are significant in the performance of a business and are an important asset for the justification of new projects. 相似文献
89.
90.
复合励磁发电机在移动电源领域有着广泛的应用前景。该文提出了一种磁路独立组合转子复合励磁发电机,介绍了其结构和磁路特点。在此基础上,提出了电机的电磁设计方法,并推导了电机重要参数E0、Xad、Xaq的计算方法。设计了一台额定功率为25kW的样机,样机试验结果表明,设计计算值准确,电机性能均达到了要求。 相似文献