碳酸及碳酸酯热消除反应的量子化学研究

用AM1方法研究了碳酸和碳酸酯的热消除反应．发现迁移基团R和基团R’共同制约这类吸热反应的活化能。     

电子自旋共振准三维图象的重建方法

根据投影切片原理, 设计了一个简单而有效的ESR图象重建算法和程序, 可利用样品的一集ESR谱, 方便地绘制出样品在某截面的自旋密度立体轮廓图、等值图和散点密度分布图等, 为分析和研究自旋密度的分布及其性质, 提供了直观依据。作为应用, 文中给出了石英杜瓦受紫外光辐照后产生的局部晶格缺陷——F心的空间分布图, 图中清楚表明, F心的浓度与辐照方向和辐照强度的密切关系, 与试验结果完全相符。     

电场作用下苏氨酸的电流特性研究

制备了以液态苏氨酸为沟道材料的四端有机场效应晶体管,观测了其随着栅极电压的不同呈现出源漏两极之间不同的电学特异现象;还观测了苏氨酸在外电场作用下,阻抗随着源漏之间电压频率变化的关系,提出一个极性液体模型解释了其导电机理。     

表面包覆改性对纳米CeO2分散性的影响

了改善纳米CeO2在Zn-Al类共晶合金中的分散性,采用超声液相包覆法对纳米CeO2进行表面活性剂表面包覆改性,并用AES测定了包覆层的厚度,用TEM研究了CeO2的团聚状况,用TGA分析了有机物包覆层的炭化温度范围,最后用FE-SEM观察了CeO2在复合材料中的分散情况。结果表明,包覆在纳米CeO2表面的厚度约为20 nm的表面活性剂层提高了微粒的分散性,而且该包覆层在495℃时已经炭化。热力学计算的结果也表明,炭化层能与氧化膜反应,该反应提高了CeO2与基体间的润湿性,并使其均匀分布在基体合金中。     

Infrared study of co adsorbed species on ru/silicalite catalyst

Carbon monoxide adsorbed species on Ru/silicalite and their reactivity towards oxygen have been studied using in situ diffuse reflectance infrared spectroscopy (DRIFT). Four species were detected: a bridge bonded CO on metallic Ru (1980 cm ^-1), a linearly adsorbed CO on metallic Ru (2040 cm^-1), a linearly adsorbed CO on partially oxidized Ru (2081 cm^-1), and a multicarbonyl on oxidized Ru (2081 and 2133 cm^-1). Among the four CO species the most strongly held species was the bridge bonded CO on metallic Ru while the multicarbonyl was the most weakly held species. These four species have different reactivities towards oxygen. Only the linearly adsorbed CO on metallic Ru can be oxidized at room temperature.     

Scalable synthesis of multi-shelled hollow N-doped carbon nanosheet arrays with confined Co/CoP heterostructures from MOFs for pH-universal hydrogen evolution reaction

Developing low-cost but efficient hydrogen evolution reaction(HER)electrocatalysts over whole pH values is a significant but daunting task for the large-scale application of electrochemical hydrogen production.Herein,we develop,for the first time,a scalable MOF-assisted strategy for the fabrication and microstructural optimization of multi-shelled hollow N-doped carbon nanosheet arrays with confined Co/CoP heterostructures on carbon cloth(Co/CoP@NC/CC)for boosting HER performances.The key to this strategy is the step-by-step epitaxial growth of unprecedented multilayer ZIF-L arrays on carbon cloth,which are subsequently pyrolyzed and controllably phosphorized to achieve the precise control over the shell number and nanoarchitectures of the Co/CoP@NC/CC.Impressively,the HER performances can be significantly enhanced by increasing hollow shell number,and the optimal triple-shelled hollow Co/CoP@NC/CC exhibits low overpotentials of 86,78 and 145 mV in acidic,alkaline and neutral media to deliver a current density of 10 mA cm^-2,respectively,ranking as one of the best Co-based HER electrocatalysts over whole pH values.Further DFT calculations suggest that the Co/CoP heterostructures can effectively boost the cleavage of H–OH to generate protons and optimize the adsorption energy of hydrogen(ΔG_H*),which,together with the large electrode/electrolyte interface and accelerated charge/mass transfer of multi-shelled hollow array structure as well as the good conductivity and dispersity,are responsible for the remarkably improved HER performances.This study not only provides a new toolbox for enriching the family of multi-shelled nanoarchitecture materials,but also points out a general and effective route to develop highly efficient self-supported electrode materials for energy-related applications and beyond.     

乙醇酸和DL─乳酸交替共聚物的合成和表征

乙醇酸和ＤＬ－乳酸交替共聚物具有不同于其无规共聚物的理化性能和生物降解性。以ＤＬ－３－甲基－１，４－二烷－２，５－二酮为单体，通过在辛酸亚锡引发下的本体开环聚合，合成了该交替共聚物，并进行了结构表征。     

Determination of Organophosphorus Pesticides in Soil by MMSPD-GC-NPD and Confirmation by GC-MS

A novel method, modified matrix solid-phase dispersion (MMSPD), has been developed for quantitative analysis of organophosphorus pesticide residues in soil. It was based on matrix solid-phase dispersion (MSPD) and continuous liquid-solid extraction (continuous LSE), using Florisil as sorbent and dichloromethane as the recycling solvent. Two soils with different texture and physicochemical properties were studied to validate the method. The effect of residence time of pesticides in soil was also studied. MMSPD was compared with MSPD and continuous LSE respectively. Determination was carried out by gas chromatography with nitrogen-phosphorus detection (GC-NPD). The method gave recoveries ranging from 72–105% with relative standard deviations (RSDs) lower than 15% for the pesticides studied. The limits of detection (LODs) ranged from 0.1 to 0.6 ng g⁻¹. Two pesticide residues have been detected in real soil samples from Fujian, China, using MMSPD. The pesticides were confirmed by gas chromatography-mass spectrometry (GC-MS) in a selected-ion monitoring (SIM) mode. Revised: 4 and 9 April 2006     

冷态德士古气化炉流场与停留时间分布的研究

测定了德士古气化炉的冷态速度分布和停留时间分布。结果表明：德士古气化炉内在轴向２．５～３．０倍直径范围内存在回流，最大回流量为射流量的３．５倍左右；在平均停留时间之前，已有５０％左右的物料逸出炉外。本文指出，德士古气化炉中存在的问题，如结渣、耐火砖寿命短、有效气体成分偏低均与炉内流场有关。