Facile preparation,spectral property and application of Ag/ZnO nanocomposites

Research on Chemical Intermediates - In this paper, a one-pot and sustainable method for the preparation of Ag/ZnO nanocomposites in green polyethylene glycol-200 (PEG-200) was reported with silver...     

Zirconia fiber membranes based on PVDF as high-safety separators for lithium-ion batteries using a papermaking method

Journal of Solid State Electrochemistry - Lithium-ion batteries have been receiving more and more attention because of the energy crisis. As an important subassembly of lithium-ion batteries, the...     

Impact Force Identification on Carbon Fibre–Epoxy Honeycomb Composite Panel Based on Local Convex Curve Criterion

Experimental Mechanics - Identification of impact force is essential for various engineering applications, such as performance evaluation, design optimisation, noise suppression, and vibration...     

Copper quinolate: A simple and efficient catalytic complex for coupling reactions

We describe an effective and novel method to prepare N-aryl imidazoles via the copper quinolate-catalyzed N-arylation of aryl halides and imidazoles. A wide range of products were obtained in moderate to excellent yields under the optimal reaction conditions. Applying standard conditions, the model reaction could be performed on a gram scale. This method also presents a new avenue to the “click” reaction of terminal alkynes, benzyl bromide, and sodium azide and to the construction of C–C bonds by homocoupling of phenylboronic acid or phenylacetylene derivatives with the aid of copper quinolate.     

Insights into the Control of Optoelectronic Properties in Mixed-Stacking Charge-Transfer Complexes

Although cocrystallization has provided a promising platform to develop new organic optoelectronic materials, it is still a big challenge to purposely design and achieve specific optoelectronic properties. Herein, a series of mixed-stacking cocrystals (TMFA, TMCA, and TMTQ) were designed and synthesized, and the regulatory effects of the acceptors on the co-assembly behavior, charge-transfer nature, energy-level structures, and optoelectronic characteristics were systematically investigated. The results demonstrate that it is feasible to achieve effective charge-transport tuning and photoresponse switching by carefully regulating the intermolecular charge transfer and energy orbitals. The inherent mechanisms underlying the change in these optoelectronic behaviors were analyzed in depth and elucidated to provide clear guidelines for future development of new optoelectronic materials. In addition, due to the excellent photoresponsive characteristics of TMCA, TMCA-based phototransistors were investigated with varying light wavelength and optical power, and TMCA shows the best performance among all reported cocrystals under UV illumination.     

无轴承旋翼柔性梁载荷特性研究

应用Hamilton原理建立了双路传力的无轴承旋翼运动方程。采用均匀入流模型,基于直升机飞行平衡条件,建立了无轴承旋翼柔性梁载荷的计算模型,并通过算例验证了模型的精度。利用该模型,研究了全机重心位置、机身气动阻力以及平尾安装角对柔性梁载荷特性的影响,给出了各因素对柔性梁载荷的影响趋势,得出了降低柔性梁载荷的方法。数值结果表明:2cm左右重心位置的变化能够引起9%~11%的柔性梁载荷变化量,15%气动阻力的增加会导致约9%的柔性梁载荷的增大;2°平尾安装角的变化引起约10%柔性梁载荷的变化量,3°平尾安装角的变化引起约26%柔性梁载荷的变化。     

F(1H-Pyrazol-4-yl)methylene-Hydrazide derivatives: Synthesis and antimicrobial activity

This paper investigates the seismic and collapse performance of shape memory alloy (SMA) braced steel frame structures considering the effects of various brace design parameters and ultimate state of SMAs. An SMA braced steel frame building is designed to have comparable strength and stiffness with a steel-moment resisting frame selected as case study building. Then, the stiffness and ultimate deformation capacity of the SMA braces in the initially designed reference SMA braced frame are systematically varied. First, the static pushover analysis and incremental dynamic analysis (IDA) are employed to illustrate the significance of SMA brace failure consideration in seismic performance assessment of steel frames with SMA elements. Then, the influence of SMA brace initial stiffness and ultimate deformation capacity on the seismic and collapse performance of SMA braced frames are studied through pushover analyses, nonlinear response history analyses, and IDA. The results show that the SMA brace initial stiffness does not affect the interstory drift and floor absolute acceleration response at design and maximum considered earthquake (MCE) level seismic hazard or collapse capacity of the frame. However, it has considerable influence on post-event functionality of the frame. It is also found that the SMA brace ultimate deformation capacity should be at least 80% of maximum inter-story drift demand at MCE level for satisfactory seismic performance, while larger values provide higher collapse capacity for the SMA braced frame.     

In Vitro Light-Up Visualization of a Subunit-Specific Enzyme by an AIE Probe via Restriction of Single Molecular Motion

Enzymes contain several subunits to maintain different biological functions. However, it remains a great challenge for specific discrimination of one subunit over another. Toward this end, the fluorescent probe TPEMA is now presented for highly specific detection of the B subunit of cytosolic creatine (CK) kinase isoenzyme (CK-B). Owing to its aggregation-induced emission property, TPEMA shows highly boosted emission toward CK-B with a fast response time and very low interference from other analytes, including the M subunit of CK (CK-M). With the aid of a Job plot assay, ITC assay and molecular dynamics simulation, it was directly confirmed that the remarkably enhanced fluorescence of TPEMA in the presence of CK-B results from the restriction of single molecular motion in the cavity. Selective wash-free fluorescence imaging of CK-B in macrophages under different treatments was successfully demonstrated.     

工业催化:选择性提升策略

工业催化直接或间接贡献了世界GDP的20%-30%,推动了产业变革和社会进步.对于工业催化,开发高活性、高选择性和高稳定性的多相催化剂至关重要,而选择性是最主要的挑战.因为实现催化选择性的精确控制是绿色化学的重要概念之一,更是工业催化可持续发展的重要驱动力;而且,选择性不仅决定了催化过程的原子经济性,也影响到后续分离过程的能耗.针对多数工业催化反应存在'活性越高、选择性越低'的相互制约与矛盾问题,本文以若干能源化工催化反应为例,试图总结催化选择性提升的一般策略,以期为有关工业应用的催化新过程提供科学参考.多相催化一般经历与反应物有关的步骤(反应物的外扩散、内扩散和化学吸附)、与反应有关的步骤(活化和表面反应)、以及与产物相关的步骤(产物脱附、内扩散和外扩散).本文依此归纳并举例说明提高选择性的一般策略.在汽油催化吸附脱硫中,主要利用了催化剂中零价镍-氧化锌耦合活性中心的选择吸附策略,使零价镍优先吸附含硫化合物,从而实现选择性脱硫而不饱和烯烃.在甲苯和甲醇侧链烷基化反应中,主要利用了特定空间分布的酸碱吸附位,实现吸附甲苯和稳定甲醛中间体的协同匹配.在乙苯脱乙基型二甲苯异构化反应中,主要利用了双床层对催化剂功能的分离策略,在不同的择形催化剂床层中分别进行乙苯脱乙基反应和二甲苯异构化反应,从而提高对二甲苯的产量.在苯选择加氢制环己烯反应中,主要利用强化产品脱附的策略,促进环己烯产品从亲水改性的催化剂表面脱附,实现环己烯选择性的提升.这些炼油与化工研究案例中同时存在多个连串-平行反应,主要是利用吸附中心、反应中心在时间或空间上的耦合、解耦或限域策略,调控不同途径的扩散能垒、反应能垒,实现了催化剂选择性的提升.多相催化多是复杂过程,基于提高选择性的初步认识,还要结合具体复杂催化过程,系统研究单策略以及多策略组合作用下的选择催化过程,实现在合理时间尺度、空间尺度上设计高选择性的催化剂,而这本质上是一种介尺度催化.