共查询到20条相似文献，搜索用时 31 毫秒
1.
圆柱射流截面形状的周向变化对界面不稳定性的影响 总被引：2，自引：0，他引：2
This paper concentrated on the effect of azimuthal variation of section shape on the instability of a cylindrical jet.A single fluid model under certain assumptions was constructed.The characteristic relation between frequency and wave number is obtained using the normal-mode method.The effect of some parameters on the stability was examined and some phenomena in experiments were explained. 相似文献
2.
An equation of atomization quantity from energy dissipation by hydraulic jump was derived from the dimensional analysis. By applying Gauss diffusion equation, the spray diffusion rule in valley was studied under the condition of continuous linear source and random wind direction. By considering the spray-rain switching process, coagulation, condensation and evaporation of droplets, the air temperature, air relative humidity,spray density and the rainfall intensity in the lower reaches of the linear source were calculated. The 3-D numerical simulation fitted well with prototype monitoring. Finally, the prediction of atomization influence on environments for Xiangjiaba Hydropower Station was conducted. 相似文献
3.
奇偶指数与链烷烃原子化热的关系 总被引：3，自引：0，他引：3
在距离矩阵的基础上提出一种新的拓扑指数一奇偶指数OE,该指数对C1-C10的150个链烷烃有很好的结构区分性。将其对C1-C9的有关链烷烃的原子化热进行结构性质相关,结果表明,该指数具有良好的性质相关性。奇偶指数计算简便,有望作为一个重要参数在QSPR／QSAR研究中得到应用。 相似文献
4.
农民原子化的后果及对策 总被引：4，自引：0，他引：4
20世纪的中国革命、市场经济以及家庭联产承包责任制的推行，动摇了农民一致行动的村庄基础，相互之间的合作越来越困难，农民日益原子化。农民成为分散和孤立的个体，无法为共同利益达成有效的合作，导致农民的市场竞争力下降、农民政治参与的积极性不高、农村公共物品供给出现严重不足等后果。农民只有组织起来才能摆脱不利的局面，国家应鼓励农民建立自己的组织。 相似文献
5.
As a sanitary, reproducible and inexpensive en-ergy resource, the hydroelectric generation has beenincreasingly used in recent years. A great number ofhuge dams have been constructed in the narrow gor-ges, with the height of around 300 m and the flooddischarging powers ranging from10 billion to100 bil-lion W. The maximum unit discharges all exceed 200m3/(s·m). With the characteristics of flood dis-charge such as high head, large discharge, narrowgorges and high frequency, the existing dams ha… 相似文献
6.
牛楠森 《四川师范大学学报(社会科学版)》2012,(4):117-121
在现代家庭中,成员间联系的强度和长度都越来越低,以至有逐渐脱离家庭共同体的"原子化"倾向。"家庭原子化"现象产生的根本原因在于个人主义和功利主义在家庭中的渗透。由于"个人主义","家庭原子化"取消了长辈的"持续‘在场’影响",再加之"功利主义"这一不利的价值观导向,家庭教育功能由此而式微。超越此"家庭原子化"遭遇,促进家庭教育功能的恢复,有必要倡导关注家庭教育的学校教育、教育政策与社会舆论。 相似文献
7.
杨超 《青海师范大学学报(哲学社会科学版)》2009,(1):15-18
在当前中国,具有主体性、创造性、能动性等有个性的人在改革开放的浪潮的催生之下不断涌现,但同时,与人的个性发展如影随形,人也出现了单子化这种人的异化现象。这种发展趋向在我国有其独特的根源。我们要遵循唯物辩证法的基本原理,研讨改革开放背景下人的发展的这一悖论,从而积极采用各种策略,使人走向全面而自由的发展。 相似文献
8.
According to the problem during mining coal seam with high gas and its control, the theory numerical calculation of gas and strata movement law caused by protection layer mining was studied, with the background of Snake Mountain coal mine. First of all, the basic principle of fluid (gas)-solid coupling was briefly described, and a three dimensional model was established by FLAC software. Secondly, the calculation parameters of fluid-solid coupling were obtained based on the measured data, and the numerical calculation of sublevel mining was carried out in turn. Lastly, initial stress state, gas movement law, deformation law of pore pressure and movement characteristics of rock strata were studied, respectively. The results show that the gas and pressure were greatly reduced with the advance of 4 coal seam working surface, as well as the constant increase of area of goaf. Facilitating gas and the stress were gradually penetrated and released to goaf during the whole process of mining. The gas pressure, the aggregation degree and the surrounding rock pressure of the 1 coal seam and the 3 coal seam were greatly reduced. 相似文献
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10.
我们将芳香性概念扩展到全金属团簇Mg3^2-,运用密度泛函理论（B3LYP,B3PW91）对全金属团簇Mg32^-,NaMg3^-和Na2Mg3的稳定结构、振动频率与电子总能量（考虑了零点能ZPE）进行理论计算。计算的结果显示,NaMg3^-和Na2Mg3团簇中包含一个正三角形的阴离子Mg3^2-。对芳香性的平面电子结构、核独立化位移（NICS）以及分子轨道的几个标准模式进行分析,分析的结果指出,2个离域化的π电子遵循4n＋2电子计算规则,并且呈现出π芳香性。 相似文献
11.
Cover systems are used to prevent water infiltration into a waste body. They also play an important role in controlling landfill gas transport from the waste body to the atmosphere. It is important to assess the flux of landfill gas at the surface of a cover system by considering the coupled effects of rainwater infiltration and gas transport in the cover soils. We have developed a 1D mathematical model for coupled transient gas and water transport in unsaturated cover soils. The coupled model was solved by the finite element method. Results obtained by the proposed model agreed well with experimental data. Based on the proposed solution, the influences of gas pressure, gas permeability, and the thickness of the cover soils on soil gas concentration profiles were investigated. The difference in soil gas concentration reached up to 31% as the thickness of cover increased from 1 to 2 m. Gas concentration at a depth of 0.2 m decreased by 6% as the amplitude of atmospheric gas pressure fluctuation increased from 20 to 100 Pa. The gas concentration increased by only 3% when gas permeability increased by a factor of 2 for a relatively long period of gas migration (e.g., 60 h) under the given conditions. Results suggest that both diffusion and advection should be considered when estimating gas transport in unsaturated cover soils. The numerical model can be used in the design of cover systems in relation to gas breakthrough time, breakthrough concentration, and flux. 相似文献
12.
提出一种新型的液体除湿系统——超声雾化液体除湿系统,该系统用超声雾化技术取代了传统塔式除湿过程中的填料,避免了由填料带来的溶液耗量大和阻力大的缺点.建立了数学模型来预测在理想条件下液体除湿过程的效率及耗液量.通过对比计算结果和传统塔式除湿的实验数据,发现后者的溶液耗量远大于理想情况下的耗量.另外,在提出的系统中除湿过程发生在通过超声作用产生的微小除湿剂液滴表面,等量的除湿剂能够产生更大的反应表面积;整个新系统中没有喷嘴和溶液泵,系统阻力和能耗相应降低.因此,该方法比塔式除湿方式更接近于理想情况. 相似文献
13.
Different two-equation k-ε models were used to simulate the gas flow field generated by a new type of circulating fluidized bed reactor with venturi gas distributor. The numerical results were compared with the experimental data. It has been shown that the simulation results from the standard k-ε model have the best match with the experimental data. Based on this model, the gas flow field in the venturi diffuser and riser was analyzed by the concept of velocity nonuniformity and dead zone percentage. Both the nonuniformity of gas velocity and the dead zone percentage reach the maximum at the venturi outlet due to the effect of the vortex. At the same time, it provides a good platform for the further optimization of the inlet configuration of circulating fluidized bed reactor. 相似文献
14.
The use of loess as an earthen final cover material is promising in northwest China which has an arid and semi-arid climate. A full-scale testing facility with an area 30 m long by 20 m wide was constructed at the Xi’an landfill of municipal solid wastes to investigate the performance of an inclined capillary barrier cover. The cover consisted of a compacted loess layer underlain by a gravel layer. The testing facility was well instrumented for a gas permeation test and recording of the soil conditions in terms of volumetric water content, pore gas pressure, and soil temperature. Tests were performed to measure the gas permeability of the compacted loess before and after the planting of vegetation on the cover. The field measurements demonstrate that the capillary break at the fine/coarse soil interface allows the upper compacted loess layer to retain more water, and conversely reduces its gas permeability, which is favorable for reducing landfill gas emissions. When the degree of saturation of the compacted loess was greater than 85%, the gas permeability decreased significantly with a further increment in volumetric water content. The growth of vegetation roots tended to fill the large pores in the upper loosely-compacted loess, resulting in a decrease in gas permeability of one order of magnitude. The influence of soil clods in the compacted loess on gas permeability can be one to two orders of magnitude due to an increase in pore size and a decrease in tortuosity. 相似文献
15.
郑殿峰 《实验室研究与探索》2011,30(5):32-34,41
设计制造了工业燃烧技术和加热炉技术的教学实验与科研装置,主要包括水套加热炉、燃油及燃气全自动燃烧机、烟气分析仪等。由全自动燃烧机为水套炉提供热源,通过燃烧室外侧水套及管式换热器,将热量传递给循环水,出口烟气温度为70~150℃;利用穿过水套的测量孔,测量燃烧室的温度场、速度场、浓度场,在烟道出口测定烟气成分。利用该装置能够进行科学全面的燃烧技术的研究和评价,并已在教学实验中取得了很好的教学效果。 相似文献
16.
建立了热风炉栅格燃烧器内空、煤气流动混合过程的三维物理、数学模型,对燃烧器内流场特性和组分浓度均匀性进行了数值模拟。计算结果揭示了燃烧器内空、煤气流场结构及混合过程;得到了燃烧器空气和煤气通道的阻力系数、速度均匀度以及组分浓度均匀度;同时分析了冷风配气均匀度的影响因素,为热风炉燃烧特性的研究奠定了基础。 相似文献
17.
首次利用激光拉曼技术对微量乙烯气体进行测试和分析,得到500 cm-1~3500 cm-1内乙烯气体的拉曼光谱。结果表明,乙烯气体的拉曼光谱有明显特征峰,这一性质为进一步研究果蔬散发乙烯气体的检测提供了依据。 相似文献
18.
To understand the absorption mechanism of nitrogen dioxide into a sodium sulfide solution, a stirred tank reactor with a plane gas-liquid interface was used to measure the chemical absorption rate of diluted nitrogen dioxide into sodium sulfide solution. The absorption rates under various experimental conditions were measured and the effects of experimental conditions on nitrogen dioxide absorption rate were discussed. The results show that, in the range of this study, nitrogen dioxide absorption rate increases with increasing sodium sulfide concentration, nitrogen dioxide inlet concentration, and flue gas flow rate, but decreases with increasing reaction temperature and oxygen content in flue gas. 相似文献
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