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991.
利用Landauer-Büttiker公式对金属导线/单臂纳米碳管/金属导线结构的热电传输进行理论计算.在有限温度梯度下,利用迭代法计算非线性热电势和热电导,研究表明,热电势和热电导与系统电子的传输行为密切相关,热电势随系统化学势的变化而振荡,且可为正也可为负值,这种行为完全依赖于电子电导的变化.研究结果对分子器件热传输的实际应用有意义. 相似文献
992.
Formation and coexistence of tricalcium silicate (C3S) and calcium sulphoaluminate (C4A3
) minerals in Portland cement clinker containing calcium sulphoaluminate were investigated. The f-CaO content, mineral composite and formation of mineral in the clinker were analyzed respectively by chemical analysis, differential
scanning calorimetry(DSC) and X-ray diffraction. The results show that, adding a suitable amount of BaO can improve the burnability
of raw meal and promote the f-CaO absorption. Tricalcium silicate and calcium sulphoaluminate minerals can form and coexist in clinkers at 1 234–1 317
°C by the addition of BaO to the raw meal. A suitable amount of BaO expanded the coexistence temperature of two minerals by
58 °.
Funded by the National Basic Research Program of China (No. 2009CB623100), National Eleven Five-Year Scientific and Technical
Support Plans (No. 2006BAF02A24), the Natural Science Fund for Colleges and Universities in Jiangsu Province(No. 08KJB430006),
the Open Fund for the Key Laboratory of Inorganical and Composite Materials in Jiangsu Province(No. wjjqfhxc1200801) and the
Innovation Fund of Doctoral Dissertation of Nanjing University of Technology (No. BSCX200705) 相似文献
993.
The catalysts of air electrode were prepared by sintering the active carbon loaded with manganese nitrate and potassium permanganate
at 360 °C The air electrode was made up of a catalyst layer, a waterproof and gas-permeable layer, a current collecting substrate
and a second waterproof and gas-permeable layer. The cell was assembled by the air electrode, pure magnesium anode and 10%
NaCl solution used as electrolyte. The microstructures of air electrodes before and after discharging were characterized by
SEM. The electrochemical behaviors of the air electrodes were determined by means of polarization curves, volt-ampere curves
and constant current discharge curves. The polarization voltage of air electrode is—173 mV (vs SCE) at the current density of 50 mA/cm2. The air electrodes exhibits good activity and stability in neutral electrolyte. The magnesium-air cell could work at 5 W
for more than 7 h. 相似文献
994.
MA制备GdSiGeDy合金系室温磁制冷性能研究 总被引:1,自引:0,他引:1
机械合金化(MA)是一种材料固态非平衡加工新技术.本文主要探讨稀土元素Dy在机械合金化工艺条件下对磁制冷合金GdSiGe磁熵变的影响,发现用机械合金化制备的GdSiGeDy合金系室温磁制冷材料不仅有光滑的磁熵变曲线,而且研究表明,由于元素Dy的加入在磁熵变达到单质Gd的两倍情况下大量减少使用昂贵元素Ge的结果,具有明显经济效益. 相似文献
995.
柴油机排气管恒温进气的内流场数值模拟 总被引:3,自引:1,他引:2
采用汽车尾气温差发电技术是一种合理有效的节能方法,而温差发电器件的安装位置将直接影响传热效果。根据柴油机排气管道的内流特点,建立流动模型,利用FLUENT软件进行了数值模拟,根据计算仿真的结果,通过对速度场、压力场、温度场和湍动能的计算值的分析,精确的指出了热量利用的最佳区域。 相似文献
996.
To predict and optimize the temperature distribution of slab continuous casting in steady operational state, a three-dimensional model (named offline model) based on the heat transfer and solidification theories was developed. Both heat transfer and flux distribution characteristics of the nozzle sprays on the slab were considered, and the complicated boundary condi-tions, such as spray cooling, natural convection, thermal radiation as well as contact cooling of individual rolls were involved in the model. ... 相似文献
997.
To overcome the limitations of traditional monitoring methods, based on vibration parameter image of rotating machinery, this paper presents an abnormality online monitoring method suitable for rotating machinery using the negative selection mechanism of biology immune system. This method uses techniques of biology clone and learning mechanism to improve the negative selection algorithm to generate detectors possessing different monitoring radius, covers the abnormality space effectively, and avoids such problems as the low efficiency of generating detectors, etc. The result of an example applying the presented monitoring method shows that this method can solve the difficulty of obtaining fault samples preferably and extract the turbine state character effectively, it also can detect abnormality by causing various fault of the turbine and obtain the degree of abnormality accurately. The exact monitoring precision of abnormality indicates that this method is feasible and has better on-line quality, accuracy and robustness. 相似文献
998.
Physical-chemical properties of phosphorous gypsum, proportion and cemented mechanism of slurry with gypsum as aggregate were
studied to remove the harms of gypsum pile, combining with difficult problems of excessive mined-out gobs, enormous ore body
under roadway and low recovery ratio of Yongshaba Mine, Kaiyang Phosphor Mine Group, Guizhou Province, China. An appropriate
backfill system and craftwork were designed, using shattering milling method to crush gypsum, double-axles mixing and strong
activation mixing way to mix slurry, cemented slurry and mullock backfill alternately process. The results show that gypsum
is fit for backfilling afterwards by adding fly ash, though it is not an ideal aggregate for fine granule and coagulate retardation.
The suggested dosage (the mass ratio of cement to fly ash to gypsum) is 1:1:6–1:1:8 with mass fraction of solid materials
60%–63%. Slurry is transported in suspend state with non-plastic strength, and then in concretion state after backfilling.
The application to mine shows the technology is feasible, and gypsum utilization ratio is up to 100%. Transportation and backfill
effect is very good for paste-like slurry and drenching cemented slurry into mullock, and the compressive strength and recovery
ratio are 2.0 MPa and 82.6%, respectively, with the maximum subsidence of surface only 1.307 mm. Furthermore, the investment
of system is about 7×106 yuan (RMB), only 1/10 of that of traditional paste backfill system.
Foundation item: Project (2006BAB02A03) supported by the National Key Technology Research and Development Program; Project (08MX16) supported
by Mittal Scientific and Technological Innovation Projects of Central South University during 2008 相似文献
999.
阐述了全要素生产率理论和技术进步的关系,并通过对某电厂10多年中各个阶段全要素生产率的实证计算和分析,说明了技术进步对电力企业效率的提高有着巨大贡献. 相似文献
1000.
远程虚拟实验室数据库的设计及访问 总被引:1,自引:0,他引:1
在基于LabVIEW的虚拟实验室平台中,引入数据库管理系统可以更加有效、安全地对用户、仪器设备和实验数据等进行管理。运用SQL Server2000设计了远程虚拟实验室平台的数据库系统,并借助LabSQL工具包实现了LabVIEW远程虚拟仪器程序对数据库的访问及操作. 相似文献