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931.
932.
在小试条件下,以石英砂为载体,利用表面负载的铁锰复合氧化膜研究了地表水和地下水催化氧化去除锰的效果差异。结果表明,保持相同的操作条件,地表水中锰去除率(20%)远不及地下水(40%)。通过对比水质参数,认为该差异可能主要取决于水中pH和碱度。将地表水pH提高至和地下水相同,去除效果未见大幅提升;而将碱度提高至和地下水相同时去除效果有较大改善,锰去除率由20%提高至40%,认为碱度含量的不同是导致不同水源水中锰去除效果差异的主要原因。进而在提高碱度至120 mg/L的基础上改变其他运行条件,以寻求保持活性氧化膜去除地表水中锰的有效方法。发现降低进水锰浓度、滤速,增加滤层厚度均有助于提高去除效率,几乎可达到与地下水相同去除率。 相似文献
933.
The corrosion behavior of an austenitic stainless steel (UNS S30400) has been characterized in a 10,000 h test conducted in hydrogenated, ammoniated water at 260 °C. The corrosion kinetics were observed to be parabolic, the parabolic rate constant being determined by chemical descaling to be 1.16 mg dm−2 h−1/2. X-ray photoelectron spectroscopy, in combination with argon ion milling and target factor analysis, was applied to provide an independent estimate of the rate constant that agreed with the gravimetric result. Based on the distribution of the three oxidized alloying constituents (Fe, Cr, Ni) with respect to depth and elemental state, it was found that: (a) corrosion occurs in a non-selective manner, and (b) the corrosion film consists of two spinel oxide layers--a ferrite-based outer layer (Ni0.2Fe0.8)(Fe0.95Cr0.05)2O4 on top of a chromite-based inner layer (Ni0.2Fe0.8)(Cr0.7Fe0.3)2O4. These compositions agree closely with the solvi phases created by immiscibility in the Fe3O4-FeCr2O4 binary, implying that immiscibility plays an important role in the phase separation process. 相似文献
934.
《Measurement》2016
Polycarbonate (PC) and Poly (methyl methacrylate) blends were prepared by incorporating Al2O3 into the polymer matrix using solution blending. The modified blends were characterized by X-ray diffraction, Thermogravimetric analysis, and Scanning electron microscopy. The crystalline to amorphous phase variation was confirmed by XRD with increase in the interplanar distance (d). TGA results indicate that the thermal stability of the modified blend was significantly improved as a function of alumina loading which may be due to interfacial interaction between the alumina particles and the polymers. Scanning electron microscopy studies reveal the presence of alumina particles resulting in plane surface morphology. The modified blends show very high dielectric constant value (105–107) as a function of frequency (in the range 50 Hz–35 MHz) and temperature in the range (40–150 °C). The modified polymer blend demonstrate consistent polarization across the frequency band 50 Hz–10 kHz. The neutral aggregates formation due to higher concentration of alumina loading demonstrated an influence on AC conductivity. This investigation can be feasible for electronic and electrical engineering application as the dielectric medium. 相似文献
935.
Effect of running‐in process on friction behaviour of carbon nitride (CNx) coating in N2 gas stream was investigated with a newly introduced two‐step ball‐on‐disk friction test, where the rubbed Si3N4 ball in the pre‐sliding (step 1) was replaced by a new CNx‐coated Si3N4 ball in the subsequent sliding stage under N2 gas (step 2). The two‐step friction test is clarified to be a simple but effective technique for obtaining contact material combination of self‐mated CNx coatings and for achieving stable and low frictions of CNx coatings. Friction coefficients of CNx/CNx in N2 gas stream decrease greatly from 0.07 without pre‐sliding to less than 0.025 in two‐step friction tests. The minimum friction coefficient of 0.004 was obtained by introducing 500 cycles of pre‐sliding in ambient air. These stable and low frictions are attributed to the generation of self‐mated CNx coatings and the formation of a lubricious layer on the disk surface. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
936.
A lab-scale anaerobic-anoxic-oxic (A^2O) process used to treat a synthetic brewage wastewater was investigated. The objectives of the study were to identify the existence of denitrifying phosphorus removing bacteria (DPB), evaluate the contribution of DPB to biological nutrient removal and enhance the denitrifying phosphorus removal in A^2O bioreactors. Sludge analysis confirmed that the average anoxic P uptake accounted for approximately 70% the total amount of P uptake, and the ratio of anoxic P uptake rate to aerobic P uptake rate was 69%. In addition, nitrate concentration in the anoxic phase and different organic substrate introduced into the anaerobic phase had significant effect on the anoxic P uptake. Compared with conventional A^2O processes, good removal efficiencies of COD, phosphorus, ammonia and total nitrogen (92.3%, 95.5%, 96% and 79.5%, respectively) could be achieved in the anoxic P uptake system, and aeration energy consumption was saved 25%. By controlling the nitrate recirculation flow in the anoxic zone, anoxic P uptake could be enhanced, which solved the competition for organic substrates among poly-P organisms and denitrifiers successfully under the COD limiting conditions. Therefore, in wastewater treatment plants the control system should be applied according to the practical situation to optimize the operation. 相似文献
937.
在实验室,采用SBR生化反应器,分别研究了经空气吹脱预处理和未经预处理的新型气化炉煤气洗涤废水经驯化建立的生态系统脱除氨态氮和COD以及脱氮模式的区别,得出以下结论:新型气化炉煤气洗涤废水可采用短程亚硝化型硝化形式直接进行生化处理。 相似文献
938.
939.
论述了我国发展高浓度复合型肥料的必要性,介绍了以尿素为氮源生产复合肥的特点,以团粒法、料浆法、熔体法和掺混法为代表,介绍了尿基复混肥的生产方法和工艺技术特征。 相似文献
940.
本文综述讨论了镁铬耐火材料中氧化铁的平衡及其使镁铬耐火材料产生体积爆胀、变疏的原因。研究指出,合理的生产工艺可以控制这种危害,使高铁铬矿得以良好利用。 相似文献