共查询到19条相似文献,搜索用时 312 毫秒
1.
2.
3.
为了提高AlSi12Fe铝熔体除气和晶粒细化的效果,通过优化超声波功率和对铝熔体处理效率的变量参数,对AlSi12Fe铝熔体进行超声波处理.实验结果:经1000W超声波功率处理1min后,40 kg的AlSi12Fe铝熔体的密度当量为1.28%,比处理前降低了45.06%;除气效果明显,晶粒级别由二级细化至一级.表明,利用超声波的空化作用,对铝熔体进行超声波处理,并选择合适的输入功率和处理效率,能实现有效提高铝合金熔体除气的效果和晶粒细化的效果. 相似文献
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
借助等离子发射光谱、电子能谱仪、X 射线衍射仪、显微硬度计、磨损试验机和振动样品磁强计等分析了超声波对化学沉积Co Fe B Ce合金涂层化学成分、晶体结构、显微硬度、磨损体积和磁性能的影响。结果表明 ,在超声波的作用下 ,化学沉积Co Fe B Ce合金涂层中Co和Ce含量提高 ,Fe和B的含量则降低 ,而且具有微晶结构的化学沉积Co Fe B Ce合金涂层转变成了晶态结构的涂层。超声波的空化作用还明显地提高了化学沉积Co Fe B Ce合金涂层的显微硬度、耐磨性、饱和磁化强度与磁导率 ,降低了涂层的矫顽力 ,改善了涂层的软磁性能。 相似文献
14.
This contribution reports the results of batch and semibatch experiments involving bubbling of nitrogen in aqueous solutions of magnesium bicarbonate, with and without the addition of either carbonic anhydrase (CA) or Scenedesmus alga to the solution. Precipitation of nesquehonite occurred during both an accelerated degassing of CO2 induced by sparging small nitrogen bubbles (representative diameter of 20 μm), and during slow degassing engendered by introducing large nitrogen bubbles (representative diameter of 5 mm). The response of the system during low rates of degassing closely approached quasi-thermodynamic predictions, which permitted an estimation of the level of supersaturation of nesquehonite, prior to the onset of precipitation. Small bubbles and CA significantly increased rates of degassing and indirectly the production of nesquehonite, as the rate of degassing can limit the precipitation process. The response of the system during rapid rates of degassing, prior to precipitation, was not entirely consistent with quasi-thermodynamic predictions. During precipitation, higher rates of degassing produced similar alkalisation and precipitation trends to that observed for lower rates of degassing. Our results agree with the formation of travertine deposits in nature, where the degassing of solutions enriched with inorganic carbon, and enhanced alkalisation by microorganisms, have been shown to influence carbonate formation. The results demonstrate a catalytic effect of CA on the rate limiting carbonate reactions, increasing CO2 exchange between nitrogen and water, and indirectly accelerating the precipitation of carbonates for a system controlled by rate of degassing. The results of this study have applications to large-scale storage of CO2 by mineralisation. 相似文献
15.
16.
The discussion covers the issues of difficult caving roof control in production faces and coal bed degassing. The methods and means meant for the directional hydraulic fracturing and coal degassing are described. The practical results of the method introduction in coal mines in Kuzbass are reported. 相似文献
17.
A procedural backbone has been formulated for parametrization of coal bed degassing technique. It is found that the preliminary
methane drainage criterion is a limit value of methane content in a coal bed to be extracted. The procedure for lower limit
of methane content includes a series of calculations, which determine the required degassing efficiency, basic parameters
of degassing holes, as well as the parameters of post-degassing methane content and methane emission in a coal bed. 相似文献
18.
地面抽采煤层气被认为是降低煤层瓦斯含量、解决煤矿安全问题的有效途径,地面抽采效果得到煤矿企业的普遍关注,但一直缺乏工程验证。以晋城寺河矿东五盘区为研究区,其煤层气地面抽采效果评价主要基于两个方面,首先将区块内14口参数检验井的现今含气量数据与原位含气量进行了对比,评价了含气量实际降低情况;其次运用煤储层数值模拟软件(CBM-SIM),通过对141口气井近7 a生产数据的历史拟合、参数修正,开展产能预测,预测了含气量随抽采时间变化规律和未来10 a、15 a的抽采效果。研究结果表明煤矿区地面煤层气抽采可以有效降低煤层瓦斯含量,通过近7 a的地面抽采,寺河矿东五盘区煤层含气量由23 m3/t降至10.51 m3/t,下降幅度平均为55%;通过储层数值模拟得出,抽采7 a、10 a和15 a后3号煤层剩余含气量分别为10.07,7.31,4.35 m3/t,降低幅度分别达57%,69%和82%。 相似文献