期刊文献+
共找到4篇文章
< 1 >
每页显示 20 50 100
窄分布双氢基封端硅氧烷低聚物的合成 被引量:4
1
作者 李涛 原华 +1 位作者 周楠 张志斌 《有机硅材料》 CAS 2014年第2期77-83,共7页
以八甲基环四硅氧烷、1,1,3,3-四甲基二氢基二硅氧烷(俗称含氢双封头)为原料,以浓硫酸为催化剂,采用平衡聚合的方法制备了不同摩尔质量的双氢基封端硅氧烷低聚物(HMDn MH)。采用红外光谱、核磁共振氢谱、凝胶渗透色谱、气相色... 以八甲基环四硅氧烷、1,1,3,3-四甲基二氢基二硅氧烷(俗称含氢双封头)为原料,以浓硫酸为催化剂,采用平衡聚合的方法制备了不同摩尔质量的双氢基封端硅氧烷低聚物(HMDn MH)。采用红外光谱、核磁共振氢谱、凝胶渗透色谱、气相色谱等分析方法对产物结构进行了确认和表征。研究了反应温度、反应时间、催化剂用量等对反应的影响。较佳反应条件为:平衡反应温度35℃、浓硫酸质量分数1.5%、反应时间6h。在此条件下可获得较高收率的窄摩尔质量分布(1.22~1.39)的HMDn MH.D4和HMMH的质量比影响产物的摩尔质量。D4含量越高(或HMMH含量越低)则产物的摩尔质量越大,且与设计值之间的偏差越大。HMDn MH的特性黏数与数均摩尔质量的自然对数之间呈线性关系,其相关系数为R2=Q994,相关性极好。 展开更多
关键词 端氢基聚硅氧烷 摩尔质量分布系数 特性黏数 1 1 3 3-四甲基二氢基二硅氧烷
下载PDF
果树施药仿形喷雾关键参数的模拟试验研究 被引量:45
2
作者 洪添胜 王贵恩 +2 位作者 陈羽白 杨丹彤 张建瓴 《农业工程学报》 EI CAS CSCD 北大核心 2004年第4期104-107,共4页
为了对仿形喷雾参数和雾滴分布质量进行系统分析,设计并制造了一套室内仿形喷雾试验装置,由变频器控制喷雾电动机的转速以调节喷雾压力,由试验架与果树样本的相对位置调节喷雾距离,由定时器控制电路调节喷雾时间。仿形喷雾试验按照不同... 为了对仿形喷雾参数和雾滴分布质量进行系统分析,设计并制造了一套室内仿形喷雾试验装置,由变频器控制喷雾电动机的转速以调节喷雾压力,由试验架与果树样本的相对位置调节喷雾距离,由定时器控制电路调节喷雾时间。仿形喷雾试验按照不同的喷雾参数组合采用正交试验的方法进行。雾滴的整体分布质量采用分布质量系数进行评价。试验结果表明,在室内环境条件下,喷雾距离是影响雾滴分布质量的首要因素,其次是喷雾压力,喷雾时间对分布质量的影响不显著。喷雾距离超过80cm时,果树内的沉积量显著减少,在喷雾距离≤50cm的范围内,增加喷雾压力有利于提高分布均匀性。 展开更多
关键词 仿形 喷雾 果树施药 分布质量系数
下载PDF
A numerical simulation of seepage structure surface and its feasibility 被引量:3
3
作者 彭康 李夕兵 +1 位作者 王泽伟 刘爱华 《Journal of Central South University》 SCIE EI CAS 2013年第5期1326-1331,共6页
According to Cubic law and incompressible fluid law of mass conservation, the seepage character of the fracture surface was simulated with the simulation method of fractal theory and random Brown function. Furthermore... According to Cubic law and incompressible fluid law of mass conservation, the seepage character of the fracture surface was simulated with the simulation method of fractal theory and random Brown function. Furthermore, the permeability coefficient of the single fracture was obtained. In order to test the stability of the method, 500 simulations were conducted on each different fractal dimension. The simulated permeability coefficient was analyzed in probability density distribution and probability cumulative distribution statistics. Statistics showed that the discrete degree of the permeability coefficient increases with the increase of the fractal dimension. And the calculation result has better stability when the fractal dimension value is relatively small. According to the Bayes theory, the characteristic index of the permeability coefficient on fractal dimension P(Dfi| Ri) is established. The index, P(Dfi| Ri), shows that when the simulated permeability coefficient is relatively large, it can clearly represent the fractal dimension of the structure surface, the probability is 82%. The calculated results of the characteristic index verify the feasibility of the method. 展开更多
关键词 fractal theory numerical simulation representative elementary volume (REV) random brown function permeabilitycoefficient fractal dimension
下载PDF
Effects of binary interactions on the color evolution of M33
4
作者 KANG XiaoYu ZHANG FengHui ZHANG Yu 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2012年第8期1505-1509,共5页
In this work, predictions of the spectral energy distribution from populations of single and binary stars are incorporated into a galactic chemical and color evolution model to explore the significance of the effects ... In this work, predictions of the spectral energy distribution from populations of single and binary stars are incorporated into a galactic chemical and color evolution model to explore the significance of the effects of the binary interactions on the color evolution of M33. We first constructed a model without binary interactions, and the model is able to reproduce most of the available observational constraints on the distribution of stellar parameters. We then run simulations with the same set of model parameters but with binary interactions considered. By comparing the results for the populations with and without binary interactions, we find that the inclusion of binary interactions makes the surface brightness greater (~0.1 mag arcsec 2) in FUV-band but smaller (~0.7 mag arcsec 2) in K-band, while it results in the FUV K color bluer (~0.8 mag). To reproduce the observations, a model that considers the binary interactions should make more gas fall onto the disk in the early time of the galaxy evolution, or increase the total stellar mass, or both. 展开更多
关键词 M33 EVOLUTION binary stars
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部