Adsorption of nicotine and tar from the mainstream smoke of cigarettes by oxidized carbon nanotubes

The adsorption of nicotine and tar from the mainstream smoke (MS) by the filter tips filled respectively with oxidized carbon nanotubes (O-CNTs), activated carbon and zeolite (NaY) has been investigated. O-CNTs show exceptional removal efficiency and their adsorption mechanism is investigated. Capillary condensation of some ingredients from MS in the inner hole of O-CNTs is observed and may be the primary reason for their superior removal efficiency. The effect of O-CNTs mass on the removal efficiencies is also studied and the results show that about 20-30 mg O-CNTs per cigarette can effectively remove most of nicotine and tar.     

光学薄膜厚度网络监控系统应用研究

以光电极值法为基本理论,以现代网络传输技术为基础,实现了光学薄膜厚度网络监控系统.文中主要描述了光电极值法的基本原理和网络监控系统的技术基础,并给出了详细实现方案及部署模型,最后通过实验验证了网络监控系统.     

低轨卫星扩频系统中的PN码混合并行捕获技术研究

以低轨卫星信道多普勒特性为背景,给出一种适用于大频偏条件下突发通信系统直接扩频序列混合并行捕获结构,并以门限信噪比下平均捕获时间最小为设计目标,对检测积分时间和判决门限设置进行讨论,给出最优配置方案。     

煤焦水蒸气气化动力学模型及参数敏感性研究

在热重分析仪上对小龙潭煤焦、府谷煤焦和晋城煤焦水蒸气气化过程进行了研究。使用收缩核模型、混合模型和随机孔模型模拟了三种煤焦水蒸气气化反应过程。结果表明,混合模型总体上模拟效果最好,收缩核模型和随机孔模型对低变质程度的小龙潭煤焦气化过程模拟效果不佳,但是适用于模拟另外两种煤阶较高的煤焦气化过程。求解了三种模型的动力学参数,并分析了不同模型参数出现差异的原因。同时,采用敏感性分析法定量研究了模型中的参数发生偏差时引起模型误差的大小,并通过比较发现反应速率常数k为敏感性因素,而混合模型中反应级数n和随机孔模型中孔结构参数ψ为非敏感性因素。     

面向有机光电材料的电子激发态结构与过程的计算方法

共轭聚合物与有机分子材料中的电子激发结构与过程决定了材料的光电功能：根据Kasha规则,低能级激发态的排序决定能否发光;最低激发态至基态的辐射跃迁与无辐射跃迁之间的竞争决定了发光效率,后者主要由非绝热耦合（声子作用）决定;电荷激发态载体的传输由电子分布与振动耦合或杂质和无序的散射弛豫过程决定．本文针对有机功能材料的发光性能,介绍两种理论方法的研究进展,即可用于计算共轭聚合物激发态结构的量子化学密度矩阵重整化群方法和计算发光效率的多模耦合无辐射跃迁速率方法．这些方法被应用于有机功能材料的性能预测和分子设计中．     

Complementary Standoff Chemical Imaging to Map and Identify Artist Materials in an Early Italian Renaissance Panel Painting

Two imaging modalities based on molecular and elemental spectroscopy were used to characterize a painting by Cosimo Tura. Visible‐to‐near‐infrared (400–1680 nm) reflectance imaging spectroscopy (RIS) and X‐ray fluorescence (XRF) imaging spectroscopy were employed to identify pigments and determine their spatial distribution with higher confidence than from either technique alone. For example, Mary’s red robe was modeled through the distribution of an insect‐derived red lake (RIS map) and lead white (XRF lead map), rather than a layer of red lake on vermilion. The RIS image cube was also used to isolate the preparatory design by mapping the reflectance spectra associated with it. In conjunction with results from an earlier RIS study (1650–2500 nm) to map and identify the binding media, a more thorough understanding was gained of the materials and techniques used in the painting.     

Trace of the interesting "V"-shaped dynamic mechanism of interactions between water and ionic liquids

The mixture of ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate, bmimBF4) and water (2.5%, molar fraction) under isothermal conditions at 80 degrees C was investigated by FTIR spectroscopy and two-dimensional correlation infrared spectroscopy (2D-IR) methods. Three regions were focused: the OH stretching band of water (3755-3300 cm (-1)), the stretching band of CH on the imidazole ring (3300-3020 cm (-1)), and the BF stretching band of anions (1310-1260 cm (-1)). During this process, water was gradually evaporated as time passed, which produced influences on the interactions among cations, anions, and water molecules. In the FTIR analysis, we found an interesting "V"-shaped changing trend in peak areas of the C-H on the imidazole ring and the B-F stretching band; the inflection of the system was 913 s, gained through the "moving window" method. A two-step variation was accordingly found during this process. Hydrogen bonds formed by water molecules with cations or water molecules with anions were destroyed by the reduction of water, making a fall in the former period of "V" process, while electrostatic interactions newly formed between anions and cations leading to a rise during the latter period of this course. In this paper, various conformations formed among cations, anions, and water molecules were clearly assigned, and we managed to trace the whole dynamic mechanism of this isothermal process by 2D-IR techniques.     

Electric-field-induced fabrication of covalently linked second-order nonlinear optical multilayer films on nonconductive substrates

A highly stable second-order nonlinear optical multilayer film was constructed on insulating substrates using the electric-field-induced layer-by-layer assembly technique. The substrates used in this method could be arbitrary. In another, the substrates could be modified with polyanion solution by spin coating as cladding layer. Then, the nonlinear optical multilayer films were assembled on the cladding layer directly by the electric-field-induced layer-by-layer assembly technique. The resulting cross-linked multilayer films fabricated by this method displayed high optical transparency, good thermal stability, and excellent nonlinear optical properties which can be made into waveguide devices directly.     

可逆加成—断裂链转移自由基聚合在制备水溶性聚合物中的应用

水溶性聚合物在工业、农业、医药等领域都有着广泛用途,但随着近年对水溶性聚合物精细化的要求,寻找新的结构可控的聚合方法已成为迫切需求.由于可逆加成-断裂链转移(RAFT)自由基聚合具有适用单体范围广、反应条件温和、不受聚合方法的限制等优点,以及可控制聚合物的嵌段、接枝、梳型、星型、无规及梯度等结构,成为合成结构可控的水溶性聚合物的最有效手段之一.本文主要讨论了单体、引发剂、链转移剂、溶剂等组成对RAFT聚合反应的影响,并介绍了利用RAFT方法制备非离子、阴离子、阳离子及两性离子水溶性聚合物的实例.     

第一性原理的形变势理论研究声学声子散射对电荷传输的影响

本文应用密度泛函理论和玻尔兹曼方程,在形变势理论的框架和驰豫时间近似下,研究了分子晶体中电子与声学声子散射对电荷传输的影响.针对蒽、萘、丁省和并五苯的计算表明,非局域化电子的传输过程主要受到来自于声学声子的散射.对于蒽晶体,与以前的Holstein-Peierls模型计算结果相比,发现纵向声学声子对空穴的散射强度是光学声子的3倍,所得到的空穴迁移率更接近超纯单晶样品的实验测量结果.同时,我们发现电子的本征迁移率比空穴还要大,应用前线轨道交叠分析可以合理地解释这一结果.