Enhancement by SO2 of initial activity for selective catalytic reduction of NO with CH3OH over \gamma-alumina

The effect of SO₂ on catalytic activity for NO reduction to N₂ by methanol in excess oxygen over $\gamma$ -alumina has been investigated. SCR activity increased initially upon exposure of a fresh $\gamma$ -alumina catalyst to SO₂ which is attributed to formation of Brønsted acid sites. Longer exposure to SO₂ leads to a decline in catalytic activity to a lower steady-state NO_x reduction activity which is independent of the SO₂ content in the feed gas.     

矿用丁腈橡胶覆盖胶橡塑整芯输送带的粘合研究

概述矿用丁腈橡胶覆盖胶橡塑整芯输送带研制的意义。通过丁腈橡胶覆盖胶配方设计试验体会，对影响盖胶与带芯粘合的丁腈橡胶类型、增塑剂品种的选择及共硫化、混炼胶的停放等因素进行讨论。     

转盘反应器固定米根霉的L－乳酸发酵

研究了米根霉的固定化方法，研制了用吸附法固定米根霉的生物转盘反应器，考察了在该反应器中培养基组成及其它操作条件对Ｌ－乳酸发酵的影响。实验结果表明，应用吸附法固定化的米根霉及生物转盘反应器进行Ｌ－乳酸发酵具有发酵速率快，Ｌ－乳酸得率高及既能用于连续发酵又能用于间歇发酵等优点     

R-卡尼丁的合成和改进

以环氧氯丙烷为原料合成了 ( R,S) -卡尼丁 ,用二苯甲酰 - L-酒石酸对其进行了拆分 ,对反应和拆分条件进行了优化 ,并用氧化还原法实现了 S-卡尼丁的消旋化 ,使其可以回收利用。     

R407系列产品专利研究

介绍了杜邦公司R407系列产品专利申请、授权和专利权有效期情况。     

基于重标极差法和神经网络的隧道变形趋势判断

为准确、科学及全面地对隧道变形进行趋势判断和预测分析,将隧道的变形过程划分为中期阶段和长期阶段,利用R/S分析对其位移序列和速率序列进行趋势判断研究,再利用PSO-BP神经网络对各阶段的变形进行预测,将预测结果与R/S分析结果进行对比,验证两者的一致性。利用两个工程实例进行检验,得出各序列的Hurst指数均大于0.5,说明各序列均具有持续变形的长期性,且位移序列的趋势性均大于速率序列的趋势性;同时,变形预测结果也显示隧道后期变形将持续增加,验证了R/S分析的准确性。     

重塑黄土与植物根系界面摩擦离散元分析

油松作为一种植根于黄土地区的常见植物,在提高黄土强度方面起重要作用。为了弄清油松根系在黄土地区的固土效应,本文采用离散单元法(Distinct Element Method)模拟根系拉拔试验,分析了法向压力、根系埋深、含水率对根-黄土界面摩擦力学特性的影响。结果表明:拉拔试验中,根-黄土界面峰值强度、残余强度随着法向力的增大而增大;峰值强度、残余强度随着根系埋深的增加而增大;随着含水率的降低,根-黄土界面峰值强度、残余强度呈增大的趋势。     

Glass transition and the rigid amorphous phase in semicrystalline blends of bacterial polyhydroxybutyrate PHB with low molecular mass atactic R, S-PHB-diol

The glass transition and the crystallinity of blends of isotactic bacterial PHB and low molecular mass atactic R, S-PHB-diols was investigated by means of differential scanning calorimetry (DSC), temperature-modulated DSC and dielectric spectroscopy. It was found that (i) T_g of crystallized blends is much lower than T_g of quenched blends, (ii) the semi-crystalline blends can only be described with a three-phase model. From the experimental results the amount of the oligomer component in the mobile amorphous as well as in the rigid amorphous phase was determined. It could be shown that the low molecular mass atactic R, S-PHB-diol is enriched in the mobile amorphous phase of the semi-crystalline blends, but 5-15% oligomer remains, however, in the rigid amorphous phase.     

Toughness Optimization of SBR Elastomers – Use of Fracture Mechanics Methods for Characterization

Elastomer materials are used in a wide application range and subjected to different loading from which failure of the material results. Because this failure is caused by initiation and propagation of cracks, the application of fracture mechanics methods for the assessment of the material is obvious. A short summary of the methods of technical fracture mechanics including possibilities of determination of crack resistance curves is given. Vulcanizates on the basis of SBR 1500 with various sulfur and carbon black contents were investigated. For describing the crack initiation and crack propagation behavior, several fracture mechanics examination methods were applied. Tear‐analyzer results were used to assess the crack propagation behavior under fatigue‐like loading conditions. Furthermore, for the characterization of the crack resistance of the materials under impact‐like loading conditions, instrumented tensile‐impact tests were performed. To obtain information about the initiation and propagation of a stable crack, quasi‐static fracture mechanics tests were applied. The results of the several tests are discussed in dependence on sulfur and carbon black contents. We found a non‐monotonous behavior of the toughness as a function of carbon black loading. An explanation is given in connection with a percolation‐like transition in filler morphology on larger length scales.

Schematic crack propagation curve for characterizing the fatigue behavior of the vulcanizates recorded in a TFA test.     

基于R语言的机器人教育微博可视化研究

本文利用R语言对关注度不高、转发量不太大的机器人教育微博进行了可视化研究。在分析技术实现过程的同时,我们得出结论是:机器人教育的舆情由教育官方媒体和企业培训机构主导;经济力量决定着参与讨论的程度;微博不是学习内容交流的主阵地。