In situ measurements of human cough aerosol hygroscopicity

The airborne dynamics of respiratory droplets, and the transmission routes of pathogens embedded within them, are governed primarily by the diameter of the particles. These particles are composed of the fluid which lines the respiratory tract, and is primarily mucins and salts, which will interact with the atmosphere and evaporate to reach an equilibrium diameter. Measuring organic volume fraction (OVF) of cough aerosol has proved challenging due to large variability and low material volume produced after coughing. Here, the diametric hygroscopic growth factors (GF) of the cough aerosol produced by healthy participants were measured in situ using a rotating aerosol suspension chamber and a humidification tandem differential mobility analyser. Using hygroscopicity models, it was estimated that the average OVF in the evaporated cough aerosol was 0.88 ± 0.07 and the average GF at 90% relative humidity (RH) was 1.31 ± 0.03. To reach equilibrium in dry air the droplets will reduce in diameter by a factor of approximately 2.8 with an evaporation factor of 0.36 ± 0.05. Hysteresis was observed in cough aerosol at RH = ∼35% and RH = ∼65% for efflorescence and deliquescence, respectively, and may depend on the OVF. The same behaviour and GF were observed in nebulized bovine bronchoalveolar lavage fluid.     

电导率仪法测定醋酸离解平衡常数

根据在“电解质溶液的电导”实验中，用电导率仪测定模型醋酸的离解平衡常数获得成功的改革成果。阐述改用电导仪测定电解质溶液的电导，既解决了常规实验教学中交流电桥测定电导率所面临的仪器资源短缺的困难，满足了实验教学的需要，又用活了一批闲置的新仪器的实验开发经验。     

纳米α-Fe2O3的制备及其催化高氯酸铵热分解

采用高温水解相转化法制备了纳米级的α-Fe2O3催化剂, 比较了NaOH、(NH4)2CO3以及尿素三种沉淀剂的作用效果. 对制得样品的尺寸、形貌和晶型等使用纳米粒度仪、透射电镜(TEM)以及X射线衍射仪(XRD)进行分析测试, 结果表明各个样品均为粒度分布均匀、分散性很好的α-Fe2O3纳米粒子. 将纳米催化剂按1.0wt%加入高氯酸铵(AP)中, 对混合物进行差热分析仪(DTA)分析, 发现添加有纳米α-Fe2O3催化剂样品的AP的分解峰有明显的提前. 其中, 以添加用尿素为沉淀剂的样品(粒度最小)的AP分解峰提前最多, 高、低温分解峰提前分别达到了78℃和9.66℃. 对以尿素为沉淀剂时催化剂粒径较小的情况进行了分析, 并解释了该纳米粒子对AP的热分解催化作用较大的原因.     

EAK基熔铸分子间炸药的熔化安全性

实验测定了不同装药尺寸的含RDX的EAK (乙二胺二硝酸盐 ,硝酸铵 ,硝酸钾三元低共熔物 )基分子间炸药的热爆炸临界温度 ,比较了Semenov、Thomas和Frank Kamenetskii临界方程对实验临界温度的处理结果 ,并由此得到了该炸药的分解动力学参数 :Arrhenius活化能为 1 5 8 2kJ·mol- 1,指前因子为 1 .4 6× 1 0 13s- 1.以分解动力学参数为主要依据 ,通过热爆炸理论推算了该炸药在熔化工艺过程中的热爆炸危险性 ,结果表明该炸药在 1 30℃以下 ,尺寸小于 2m的设备中进行工艺操作是安全的     

柠樣酸铋的制备、结构表征及其在固体推进剂中的催化作用

以柠檬酸、氧化铋为原料，制备了柠檬酸铋(CIT-Bi)，收率达到80%，釆用FT-IR、元素分析和X荧光衍射法对其结构进行了表征。研究了柠檬酸铋对双基和RDX-CMDB推进剂燃烧的催化作用，结果表明，柠檬酸铋对双基系推进剂燃烧有良好的催化作届，能显著提高推进剂的燃速，降低压カ指数,特别是与少量炭黑复合后，对推进刹的催化效率更高。用热重-微商热重分析(TG-DTG).X荧光衍射法和FT-IR研究了柠檬酸铋催化剂的催化作用机理。     

三乙酰基三甲酰基六氮杂异伍兹烷分子结构理论研究

采用Gaussian 98软件包,在B3LYP/6-31G水平下,对三乙酰基三甲酰基六氮杂异伍兹烷( TATFIW)的分子结构进行了全优化和频率计算,通过理论上对TATFIW的分子结构（键长、键角、二面角、电荷）的分析,知TATFIW存在分子内氢键,在硝硫混酸中硝解乙酰基易于离去,与实验吻合。文中给出了TATFIW的IR振动频率、强度计算值与实验值的对比,振动频率相对误差小于3.6%．     

电气绝缘子污闪的大气物理化学因素作用机理

根据大气物理化学的基本原理,论述了绝缘子的积污、雾的酸化、粉尘粒子及电解质溶液的导电性诸因素的相互作用与绝缘子污闪之间的关系,并据此做出了几项推断。通过此项研究,期望揭示绝缘子污闪与大气关系的一般性规律。     

Surface constructions of nano TiO_2 as the environmental and energy materials

TiO_2 has attracted an increasing attention because of its variety of potential applications in environments and energies,such as gas sensing,self-cleaning,solar energy conversion, wettability and photo-catalysis applications.In this presentation,we summarize some progress in surface constructions of nano TiO_2 and its characterizations of physicochemistry and properties. (1)Superhydrophobic nanostructure TiO_2 films Superhydrophobic nanotube,nanopore and sponge-like structure TiO_2 films are fabricated ...     

化学起爆的动力学过程研究

本文研究了化学起爆剂BrF3 、NF4BF4与有机燃料的化学反应动力学过程,实测了动力学参数,并在约束和非约束条件下实现了液化石油气、环氧丙烷气云的化学一次起爆.研究结果证实,化学一次起爆能够实现的主要因素是该自加速化学反应活化能较低,自由化学键的给予体具有极强的化学活性, NaBrF4与液化石油气反应的活化能为6.2kJ/mol,NF4BF4与环氧丙烷、液化石油气反应活化能为8.9和6.2kJ/mol,远低于一般化学反应的活化能 (41.84～418.4kJ/mol).化学起爆剂与有机燃料的反应诱导时间在0.1～1ms.