One-Pot Fabrication of Pd Nanoparticles@Covalent-Organic-Framework-Derived Hollow Polyamine Spheres as a Synergistic Catalyst for Tandem Catalysis

Facile fabrication of nanocatalysts consisting of metal nanoparticles (NPs) anchored on a functional support is highly desirable, yet remains challenging. Covalent organic frameworks (COFs) provide an emerging materials platform for structural control and functional design. Here, a facile one-pot in situ reduction approach is demonstrated for the encapsulation of small Pd NPs into the shell of COF-derived hollow polyamine spheres (Pd@H-PPA). In the one-pot synthetic process, the nucleation and growth of Pd NPs in the cavities of the porous shell take place simultaneously with the reduction of imine linkages to secondary amine groups. Pd@H-PPA shows a significantly enhanced catalytic activity and recyclability in the tandem dehydrogenation of ammonia borane and selective hydrogenation of nitroarenes through an adsorption–activation–reaction mechanism. The strong interactions of the secondary amine linkage with borane and nitroarene molecules afford a positive synergy to promote the catalytic reaction. Moreover, the hierarchical structure of Pd@H-PPA allows the accessibility of active Pd NPs to reactants.     

Poly-3BCMU薄膜上光栅的制备

报道了利用光致漂白现象在Poly－3BCMU薄膜上制备光栅的方法。对于不同条件下制备的光栅的衍射效率进行了测量。并建立了简单的模型，对实验结果进行了解释。     

五氧化二钒催化钾碱液吸收二氧化碳的机理

从五氧化二钒(V_2O_5)的物理化学性质出发,研究了V_2O_5加快CO_2在钾碱液(K_2CO_3)中的吸收速率的化学作用机理。实验证明: 当9相似文献   

Synthesis and characterization of 9-(cycloheptatrienylidene)fluorene derivatives: acid-triggered "switch on"of fluorophores

A series of 9-(cycloheptatrienylidene)fluorene derivatives were synthesized in good yields through the Suzuki or Sonogashira cross-coupling reactions. Fluorescence "off-on" behaviors of these compounds were investigated on the basis of variable acid concentrations. These compounds were shown to be acid-sensing fluorophores with utility as indicators in acidic environments.     

Crystal structure,thermal behaviour and detonation characterization of bis(4,5‐diamino‐1,2,4‐triazol‐3‐yl)methane monohydrate

Bis(4,5‐diamino‐1,2,4‐triazol‐3‐yl)methane monohydrate (BDATZM·H₂O or C₅H₁₀N₁₀·H₂O) was synthesized and its crystal structure characterized by single‐crystal X‐ray diffraction; it belongs to the space group P (triclinic) with Z = 2. The structure of BDATZM·H₂O can be described as a two‐dimensional ladder plane with extensive hydrogen bonding and no disorder. The thermal behaviour was studied under non‐isothermal conditions by differential scanning calorimetry (DSC) and thermogravimetric/differential thermogravimetric (TG/DTG) methods. The detonation velocity (D) and detonation pressure (P) of BDATZM were estimated using the nitrogen equivalent equation according to the experimental density. A comparison between BDATZM·H₂O and bis(5‐amino‐1,2,4‐triazol‐3‐yl)methane (BATZM) was made to determine the effect of the amino group; the results suggest that the amino group increases the hydrophilicity, space utilization and energy, and decreases the thermal stability and symmetry of the resulting compound.     

醋酸综合症对电影胶片影像影响研究

醋酸综合症是醋酸纤维素酯电影胶片特有病害现象，是威胁其安全保存的主要因素。醋酸综合症导致电影胶片的几何尺寸改变、机械强度降低、影像信息严重受损。本文采用基恩士VK-X250K形状分析激光显微镜研究了醋酸综合症电影胶片片基层表面粗糙度；采用X-Rite Model VS450分光光度计研究了其表面对可见光的反射率。实验结果表明胶片发生醋酸综合症之后，其表面粗糙度增大，对可见光的漫反射增强。由此可以说明醋酸综合症发生之后，胶片表面析出的增塑剂形成粗糙界面，对可见光的漫反射增强，在放映过程中透射光减弱，这是胶片记载影像受损的主要因素。     

基于能量函数的SMES优化布局研究

SMES的快速功率响应特性可以实现电力系统的主动致稳,为电力系统稳定问题提供有效的解决途径。分布式SMES的布局作为SMES应用过程中一个关键问题,是其在电力系统中实现工程化应用的重要技术课题。文中采用能量函数方法,对分布式SMES的布局问题进行研究。首先采用暂态能量函数法进行故障扫描,然后分析网络中暂态能量的分布特性,将电力系统的全局稳定性问题映射于网络局部的稳定性问题,确定系统的薄弱环节,在此基础上提出多机系统中的SMES优化布局方案。基于三机九母线系统模型进行仿真,验证了本方案的有效性。     

In vivo and in vitro metabolism of aspirin eugenol ester in dog by liquid chromatography tandem mass spectrometry

Aspirin eugenol ester (AEE) is a promising drug candidate for treatment of inflammation, pain and fever and prevention of cardiovascular diseases with fewer side effects than its precursor, aspirin. Investigation into its metabolic process in target animal species will help to illustrate its mechanism of action and to establish its residual mark compound to formulate its dosage. Six beagle dogs were orally given a dose of 20 mg kg^?1 of AEE and one dog was used to prepare blank liver microsomes. Their liver microsomes were prepared for in vitro study and their plasma and urine were collected for in vivo metabolic analysis using liquid chromatography tandem mass spectrometry. In this study we identified 10 metabolites, M1, M2, M3, M4, M5 in phase I and M6, M7, M8, M9, M10 in phase II. Based on the metabolites of AEE, the pathways of AEE metabolism in dog were demonstrated. Copyright © 2014 John Wiley & Sons, Ltd.