共查询到20条相似文献,搜索用时 31 毫秒
1.
2.
3.
Effect of Rare Earths on Diffusion Coefficient and Transfer Coefficient of Carbon during Carburizing 总被引:5,自引:0,他引:5
Newachievementsintheapplicationofrareearths (RE)tothermochemicaltreatmentssuchascarburizingandnitridinghavebeenmadeoverthepast 1 5years .TheresultsshowthattheadditionofREnotonlyresultsinpro cessacceleration ,butalsosignificantlyim provesboththemicrostructu… 相似文献
4.
5.
6.
本文研究了两种形式的插入件对辐射换热器综合传热系数K的影响。比较可知,网状插入件与板翅状插入件相比对提高换热器的K值更有效,同时也研究了换热器的操作参数对综合传热系数及阻力损失的影响。 相似文献
7.
8.
9.
10.
11.
Elsa Moggia 《中国稀土学报(英文版)》2014,32(10):979-988
This work dealt with the computation of the mean activity coefficients of rare-earth halide aqueous solutions at 25℃, by means of the Quasi Random Lattice(QRL) model. The osmotic coefficients were then calculated consistently, through the integration of the Gibbs-Duhem equation. Using of QRL was mainly motivated by its dependence on one parameter, given in the form of an electrolyte-dependent concentration, which was also the highest concentration at which the model could be applied. For all the electrolyte solutions here considered, this parameter was experimentally known and ranged from 1.5 to 2.2 mol/kg, at 25 ℃.Accordingly, rare- earth halide concentrations from strong dilution up to 2 mol/kg about could be considered without need for best-fit treatment in order to compute their osmotic and mean activity coefficients. The experimental knowledge about the parameter was an advantageous feature of QRL compared to existing literature models. Following a trend already observed with low charge electrolytes,a satisfactory agreement was obtained with the experimental values for all the investigated rare-earth chlorides and bromides. For the sake of compactness, in this work the considered rare-earth halides were all belonging to the P63/m space group in their crystalline(anhydrous) form. 相似文献
12.
将岩体和节理抽象为Kelvin黏弹性介质,建立谐波穿过黏弹性节理的传播模型,分析了谐波在黏弹性节理的透、反射系数和子波穿过节理后的波形变化规律。研究结果表明,黏弹性节理具有低通滤波特性,导致Ricker子波穿过黏弹性节理后,透射波振幅减小,主瓣不突出,波形在时域上变得更平缓;波形相关系数主要反映子波穿过黏弹性节理后发生的相位变化,而波形变化系数能综合反映子波的振幅和相位变化,因而两者描述子波波形变化时具有不同的变化规律;相对于切向刚度和切向黏性系数,节理的法向刚度和法向黏性系数对子波波形变化影响更大。 相似文献
13.
14.
15.
采用高温熔融对铁矿石试样进行预处理,以消除矿物效应。X射线荧光光谱法测定铁矿石中TFe,Al2O3,CaO,MgO,SiO2,P,Cu,Pb,Zn,As,Sn,Ti,Mn时,应用SUPERQ软件中的理论系数法、经验系数法对各组分进行校正,计算出各组分分析曲线的校正常数和拟和精度,得到最佳工作曲线,取得满意的结果。 相似文献
16.
烟化熔炼中粉煤的燃烧过程及空气系数的确定 总被引:3,自引:1,他引:2
介绍了烟化炉熔炼生产铅锌等氧化物时粉煤燃烧过程的特点,研究了空气系数α对烟化熔炼之重要冶金参数的影响,提出还原吹炼期合理的α的取值范围。 相似文献
17.
通过对常见的几种标准或计算方法进行比较和分析,提出各种阻力系数的合理取值范围以及功率计算中安全系数和备用系数的选取原则。 相似文献
18.
郭立宏 《有色冶金设计与研究》2012,33(4):56-58
针对目前国内构筑物水池的专业结构计算软件尚不成熟,结构设计者只能凭借手算加经验进行工程设计的情况,对矩形水池荷载计算、不同规范的分项系数取值及计算边界条件、计算假定及底板计算进行了探讨,并指出有限元软件可高效准确地进行水池设计计算,是今后发展的方向。 相似文献
19.
胶结充填体矿柱结构可靠性设计方法 总被引:2,自引:0,他引:2
胶结充填体矿柱广泛应用于地下矿山,矿柱结构的稳定性直接关系到采矿生产安全,胶结充填体矿柱结构可靠性设计日益受到重视和普遍应用。传统的安全系数法不能考虑影响胶结充填体矿柱结构稳定性因素的随机性和离散性,因而其结论具有很大的局限性。变异安全系数法可以可靠性理论为基础,充分考虑胶结充填体矿柱结构稳定性影响因素的随机性及其离散程度,计算结果更具指导性。章从胶结充填体矿柱力学分析入手,分析了安全系数法的局限性,详细介绍了变异安全系数法及其用于胶结充填体矿柱结构可靠性设计的方法。 相似文献
20.
There are a number of circumstances in which the use of the Pearson product-moment correlation is inappropriate and a rank order procedure (Tau) is required. The advantages of Tau over Spearman's rho technique are discussed. Definitional and computational formulae of Tau, tests of significance, the confidence limits of Tau, and the relationship between Tau and the product-moment correlation, are presented. Additional useful formulae are included. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献