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11.
The scale along the coordinate axes in the equations of motion hitherto used for an H-maser (in relative units) is shown to depend on Q as the quality factor for an H-maser. This hinders both analysis of the operation of the H-maser and optimization of its parameters. The modified equations of motion proposed here do not have that shortcoming. We determine the atomic flux into the bulb that gives the H-maser the best metrological characteristics. 相似文献
12.
根据通信导航设备在雷击中的损坏现象,提出了电源防雷措施,即实施分级保护,在多雷区配置防雷变压器。简单介绍了级间配合,抑制横向过电压的产生,以及接地阻抗的简单计算和正确选用等,以达到对电源系统的有效防雷保护。 相似文献
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高热流密度电加热元件 总被引:1,自引:0,他引:1
本文论述了用于液态金属钠热工水力性能研究的高热流密度模拟电加热元件的结构特点、材料选择、热电偶设置及其他与棒束传热实验研究有关的问题。 相似文献
16.
在介绍“铝丝印”概念的基础上,从金属腐蚀学的观点出发,分析了“铝丝印”形成的电化学腐蚀机理,并提出了具体的解决措施。 相似文献
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F Javier Benítez Ana I Leal Francisco J Real Juan L Acero Gloria Roldán 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2008,83(3):309-316
BACKGROUND: The first stage of the cork industrial process generates great volumes of wastewater with moderate to high organic pollutant content that must be purified using different procedures, such as filtration by membranes. RESULTS: The tangential filtration of these wastewaters was studied using two different laboratory equipments. In the first one, three ultrafiltration (UF) membranes were tested, with molecular weight cut‐off (MWCO) 100 kDa and 30 kDa, and two operating modes were used: total recycling of permeate and retentate streams, and in continuous mode, without recycling both streams. In the total recycling UF experiments, the influence of the operating variables on the permeate flux was first established. The effectiveness of the different membranes was determined by evaluating the rejection coefficients for several parameters that measure the global pollutant content of the effluent. The values found for these rejection coefficients were in the following order: ellagic acid and color > absorbance at 254 nm > tannic content > COD (chemical oxygen demand). In the continuous mode experiments, the fouling mechanism for each membrane was established by fitting the experimental data to various filtration fouling models given in the literature. The operating mode in the second equipment was batch concentration, and additional experiments were carried out with an UF membrane (2 kDa), and with a NF membrane (with MWCO in the range 150–300 Da). CONCLUSIONS: The three operating modes tested provided different rejection levels of organic matter; among them, the most effective procedure tested was batch concentration mode using a NF membrane. Copyright © 2007 Society of Chemical Industry 相似文献
20.
Sea-air flux of CO2 in the Caribbean Sea estimated using in situ and remote sensing data 总被引:2,自引:0,他引:2
Empirical relationships between sea surface carbon dioxide fugacity (fCO2sw) and sea surface temperature (SST) were applied to datasets of remotely sensed SST to create fCO2sw fields in the Caribbean Sea. SST datasets from different sensors were used, as well as the SST fields created by optimum interpolation of bias corrected AVHRR data. Empirical relationships were derived using shipboard fCO2sw data, in situ SST data, and SST data from the remote sensing platforms. The results show that the application of a relationship based on shipboard SST data, on fields of remotely sensed SST yields biased fCO2sw values. This bias is reduced if the fCO2sw-SST relationships are derived using the same SST data that are used to create the SST fields. The fCO2sw fields found to best reproduce observed fCO2sw are used in combination with wind speed data from QuikSCAT to create weekly maps of the sea-air CO2 flux in the Caribbean Sea in 2002. The region to the SW of Cuba was a source of CO2 to the atmosphere throughout 2002, and the region to the NE was a sink during winter and spring and a source during summer and fall. The net uptake of CO2 in the region was doubled when potential skin layer effects on fCO2sw were taken into account. 相似文献