排序方式： 共有9条查询结果，搜索用时 453 毫秒
1
1.
本文采用精确的数学解析式描述环境对学习者的愉快感和兴趣度的影响，以及由此导致的学习者情绪水平的变化规律，建立了环境对学习者情绪状态影响数学模型，对环境的结构层次进行了深入的分析，形成了一个激发学习者饱满情绪为评价指标的教学理念。 相似文献
2.
3.
The lanthanum aluminum mesoporous materials were synthesized using sodium dodecyl sulfate as a template agent by ultrasonic hydrothermal method.The resulting samples were characterized by low angle X-ray diffraction(XRD),N2 adsorption-desorption studies,transmission electron microscopy(TEM)and surface morphology analysis(SEM),surface acid(NH3-TPD),reducibility properties(TPR),X-ray energy dispersive spectrometer(EDS)and thermogravimetric analysis(TG/DTG).A l/La composite mesoporous material were synthesized with n(Al)︰n(La)=70︰1.0,80°C of reaction temperature,20 h of reaction time,12 h of crystallization time,650°C of calcination temperature.The specific surface area of the sample is 273.90 m 2 ·g ?1 ,with the average diameter 5.642 nm and pore volume 0.2354 cm 3 ·g ?1 .The samples have mesoporous structure and its particles are similar to a worm-shaped tubular structure.The influence of calcination temperature on the surface physical and chemical properties of Al/La composited mesoporous materials was examined,and the results showed that the acid strength was increased but the amount of acidic sites is decreased as the calcination temperature increased.It was found that the sample calcined at 650°C had appropriate acid content,acid strength and better reducibility. 相似文献
4.
炼油厂实际生产方案随着原油的种类以及产品需求的变化而变化,氢气网络的耗氢量和产氢量也会随之变化。笔者在详细分析了某炼油厂氢气网络成本特点的基础上,考虑制氢装置产氢量的动态变化,首次采用预测精度较高的回声状态网络对氢气网络动态用氢成本进行数据驱动建模及预测,然后根据预测出的成本在不同工况下最小用氢成本的优化操作区域中的位置,对氢气网络中氢气流量的合理配置提供决策支持。 相似文献
5.
以Zn-MCM-41介孔分子筛为催化剂,考察了其在正辛醇乙氧基化反应中的催化特性。结果表明,升高反应温度、增加初始压力以及提高催化剂用量,环氧乙烷反应速度增加。产物正辛醇聚氧乙烯醚相对分子质量分布较窄。当环氧乙烷平均聚合度为5.0时,正辛醇聚氧乙烯醚相对分子质量分布选择性系数达到19。 相似文献
6.
7.
8.
9.
1
