Synthesis of organobentonite-supported Pd composite catalyst used for the catalytic transfer hydrogenation of polyunsaturated fatty acid methyl ester

Journal of Materials Science - In this work, via the method of wet impregnation and chemical reduction, low-cost and available bentonite modified by cetyltrimethylammonium bromide (CTAB) was...     

Design of Domain Structure and Realization of Ultralow Thermal Conductivity for Record‐High Thermoelectric Performance in Chalcopyrite

Chalcopyrite compound CuGaTe₂ is the focus of much research interest due to its high power factor. However, its high intrinsic lattice thermal conductivity seriously impedes the promotion of its thermoelectric performance. Here, it is shown that through alloying of isoelectronic elements In and Ag in CuGaTe₂, a quinary alloy compound system Cu_1?xAg_xGa_0.4In_0.6Te₂ (0 ≤ x ≤ 0.4) with complex nanosized strain domain structure is prepared. Due to strong phonon scattering mainly by this domain structure, thermal conductivity (at 300 K) drops from 6.1 W m^?1 K^?1 for the host compound to 1.5 W m^?1 K^?1 for the sample with x = 0.4. As a result, the optimized chalcopyrite sample Cu_0.7Ag_0.3Ga_0.4In_0.6Te₂ presents an outstanding performance, with record‐high figure of merit (ZT) reaching 1.64 (at 873 K) and average ZT reaching 0.73 (between ≈300 and 873 K), which are ≈37 and ≈35% larger than the corresponding values for pristine CuGaTe₂, respectively, demonstrating that such domain structure arising from isoelectronic multielement alloying in chalcopyrite compound can effectively suppress its thermal conductivity and elevate its thermoelectric performance remarkably.     

Real-time energy-efficient anticipative driving control of connected and automated hybrid electric vehicles

In this paper, we propose a real-time energy-efficient anticipative driving control strategy for connected and automated hybrid electric vehicles (HEVs). Considering the inherent complexities brought about by the velocity profile optimization and energy management control, a hierarchical control architecture in the model predictive control (MPC) framework is developed for real-time implementation. In the higher level controller, a novel velocity optimization problem is proposed to realize safe and energy-efficient anticipative driving. The real-time control actions are derived through a computationally efficient algorithm. In the lower level controller, an explicit solution of the optimal torque split ratio and gear shift schedule is introduced for following the optimal velocity profile obtained from the higher level controller. The comparative simulation results demonstrate that the proposed strategy can achieve approximately 13% fuel consumption saving compared with a benchmark strategy.     

3GPP R165G核心网络技术研究

5G通信技术开启了一个新的通信时代.5G核心网作为5G网络架构中重要的组成部分,具有重要的研究意义.对此,从3GPP 5G标准化演进情况、5G核心网网络架构和R165G标准中新增核心网关键技术等几个部分对5G核心网络技术进行介绍.     

含有端基和碳桥结构的OSG薄膜性能研究

研究了具有甲基末端和碳桥结构的多孔有机硅酸盐玻璃(OSG)薄膜的化学组成、孔结构和力学性能。对薄膜进行不同的固化处理,形成稳定的多孔薄膜结构。结果表明,在空气环境中固化时,由于氧气的存在,碳桥形成硅醇的过氧化物自由基被破坏,薄膜的机械性能降低。尽管氮气固化样品中保留了乙烯桥接基团,空气固化样品的力学性能仍优于氮气固化样品。原因是空气固化中微孔的坍塌增加了薄膜内部密度,为硅醇基团的缩合创造了更有利的条件。     

胶结砂砾石料剪胀方程研究

分析了胶结砂砾石料的剪胀特性及其与围压、胶结掺量之间的关系,探讨了Rowe剪胀方程、修正剑桥模型的剪胀方程对胶结砂砾石料剪胀性的适用性,在此基础上提出一种新的胶结砂砾石料剪胀模型。研究表明：修正剑桥模型的剪胀方程不能反映胶结砂砾石料的剪胀性;Rowe剪胀方程在一定程度上能反映粗粒土的剪胀性,但高围压下在压缩阶段低估了其压缩性、而在剪胀阶段则高估了其剪胀性。提出的新剪胀方程是一种二次函数,参数简单,只需通过胶结砂砾石料三轴剪切试验即可确定,利用几种胶结砂砾石料的试验结果能很好地验证其适用性。     

磷改性对氯化Ni-W/SiO2/γ-Al2O3降烯烃催化剂性能的影响

采用氯化处理后的硅铝载体，通过等体积浸渍法分别制备了磷改性前后的两种Ni-W/硅铝催化剂。利用FR/IR-560和Digisorb-2400物理吸附仪对两种催化剂的酸度、比表面积、孔径和孔容等进行了表征，同时利用荧光指示剂吸附法对磷改性前后催化剂降烯烃的性能进行了考察。结果表明，磷改性使催化剂的B酸中心数量增加了0.02 mmol·g^－1，而B酸中心的增加有利于双分子的氢转移反应,避免反应过程中催化剂表面的积炭。在催化剂活性方面，磷改性使催化裂化汽油中的烯烃含量降低了3.06个百分点，同时提高了产品油的液体收率；从产品分布看，含磷催化剂的液体产品中异构烷烃和芳烃比例均有所提高，说明磷的加入增加了异构化和芳构化的反应活性。     

基于实际工程及虚拟装置的直流输电控制保护模型设计方法

交直流大电网的仿真,要求高压/特高压直流输电控制保护模型功能完备、特性准确,同时期望模型有良好的仿真速度,为此提出了基于实际工程及虚拟装置的控制保护模型设计方法。首先,提出了控制保护模型逻辑结构的构成方法,说明了各层级虚拟装置的功能;然后说明了在电磁暂态仿真软件中实现虚拟装置的原理。以灵绍特高压直流工程为例,在多种电磁暂态仿真软件中分别构建了控制保护模型,并仿真验证了模型的精确性及并行计算能力。     

基于相移小波的信号包络提取方法研究

针对现有的包络解调方法对噪声宽容性差的不足，论文利用窄带调制类型信号相关函数的一个基本特性，建立了基于相移小波的信号包络提取方法。该方法采用Morlet小波为基小波，根据信号的中心频率和采样率等已知信息，能够有效地提取信号的包络，并且对低信噪比信号也具有良好的宽容性，仿真结果证明了该方法的有效性，并且证明了该方法的性能优于现有的其他解调方法。最后，采用该方法对一个实测的水声数据进行了分析处理，也取得了令人满意的结果。