丙烯抗冲共聚产品EPF30R的开发

介绍了聚丙烯抗冲共聚产品EPF30R的工艺生产特点,并详细阐述了EPF30R重要物理性能与相关工艺控制参数的关系。通过调整TEAL/DONOR比、液相和气相聚合中的氢气浓度、气相组份和乙烯含量,使多相共聚物EPF30R具有良好的高刚性、流动性和冲击性能。     

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。     

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。     

二氧化钛固载杂多酸催化剂的制备及其光催化性能研究

采用浸渍法以TiO2为载体制备了固载型杂多酸光催化剂--H3PW12O40/TiO2,H8SiW12O42/TiO2,H7PMo12O42/TiO2.通过Hammett指示剂与紫外光谱相结合的方法测定固体杂多酸催化剂的酸度,分别考察杂多酸种类、浸渍时间、浸渍浓度、烧结方式、烧结温度对催化剂酸度的影响,并对所制备的催化剂进行了红外光谱和光催化活性测试.结果表明,杂多酸固载到TiO2的表面,得到了催化活性较TiO2更强的复合杂多酸光催化剂,其对酸性大红3R的降解率从纯TiO2的79%提高到91%.以磷钨酸水溶液浸渍TiO2,浸渍浓度为0.10 mol·L-1 ,浸渍时间为28 h,烘干温度为120℃,微波炉焙烧功率为650 W,烧结时间为40 min制得的催化剂活性最高.在HPA-TiO2光催化系统中,杂多酸显著加速电子从TiO2表面到O2分子的传递,改变了TiO2光催化反应历程,从而提高光催化效率.     

快固化、无收缩特种MMA-R17树脂在设备基础灌浆,锚固及修补中应用

本文介绍国外聚合物砂浆的性质和应用、施工配比及物理机械性能，供设计人员参考。     

多项式方程区间内求根基于R2空间的3次裁剪方法

多项式方程的求根问题在求交、最近距离计算等方面有着广泛的应用.3次裁剪求根方法充分利用了Bernstein基函数较好的计算稳定性,避免了数值迭代求解的不稳定性,同时具有4次收敛的速度.不同于传统的基于R1空间内的3次裁剪方法,提出了基于R2空间内的3次裁剪方法.首先引入R2空间中一条曲线(t,f(t)),在该曲线给定的区间上选取3个点,并计算这3个点及其对应的切向;然后求解3次多项式曲线Ai(u),满足同时插值这3个点及其中2个点处的切向;最后选择适当的重新参数化函数φ(t),使得Ai(φ(t))和f(t)之间具有5次逼近阶.若给定的参数区间Φ充分小,A1(φ(t))和A2(φ(t))可以在区间Φ内直接包住f(t),从而节省了用于求解包围多项式的大量计算.实例结果表明,该方法具有更好的逼近效果、更快的收敛速度和更高的计算效率.     

多单体熔融接枝天然橡胶及其性能的研究

以甲基丙烯酸缩水甘油酯（GMA）为接枝单体，苯乙烯（St）为接枝共单体，过氧化二异丙苯（DCP）为引发剂，通过熔融接枝法制备接枝天然橡胶[NR-g-（GMA-co-St）]。研究了GMA、St及DCP用量和接枝温度对NR的接枝率及其力学性能的影响。结果表明，GMA、St和DCP质量分数分别为8％、4％和0．3％，接枝温度为160℃时，NR-g-（GMA—co—St）的接枝率最高，综合力学性能最好；St的加入能明显提高NR的接枝率，并能减轻NR的降解；红外光谱的分析证实了GMA已接枝到天然橡胶分子链上。     

32位和8位单片机的无线传感器网络系统

采用STM32F10X系列的芯片为主芯片、SH79F32为辅芯片,温度传感器DS18B20做采集工具,PTR8000无线模块做通信工具,实现无线传感器网络功能。通过Altium Designer Release 10进行原理图设计及PCB板的绘制,并制作电路板、焊接电路板,之后利用Keil软件设计程序,实现不同单片机之间的无线传感器网络通信,并完成了无线通信平台的设计与制作。