羟基启动苯液相光氧化产物的傅里叶变换红外光谱研究

苯是大气中常见的挥发性有机化合物,它能溶于大气水滴、云雾等水相中,与水相中的过氧化氢在太阳光的照射下会发生液相光氧化反应。利用自制的液相反应装置研究了羟基启动苯液相光氧化反应,利用傅里叶变换衰减全反射红外光谱仪测量了液相反应产物的分子官能团,定性分析了产物的化学组分。实验结果表明,在没有过氧化氢存在时,在光照3 h后,苯溶液的红外谱图中含有苯环C-H和C=C双键伸缩振动吸收峰官能团,溶液中仅存在苯有机物,没有新产物产生。苯和过氧化氢的混合溶液在紫外光照3 h后,反应产物溶液的红外谱图除了含有苯环C-H和C=C双键伸缩振动吸收峰外,还含有O-H和C-O-C键的伸缩振动吸收峰,表明羟基启动苯液相光氧化反应形成了酚类化合物和芳香醚产物。这为研究苯液相光氧化机理提供了实验依据。     

异戊二烯及其光氧化产物的傅里叶变换红外光谱研究

利用傅里叶变换红外吸收光谱,测量得到了异戊二烯单体分子的光谱信息,采用Gaussion03程序,通过密度泛函方法计算得到异戊二烯的红外光谱,理论结果与实验结果符合较好.利用自制的烟雾腔模拟研究.OH自由基启动的异戊二烯光氧化过程,使用傅里叶变换红外光谱仪,测定光氧化产物的分子官能团,定性分析产物组分.结果表明产物中含有羰基化合物、C-O键化合物、醛、酮、羧酸及硝酸类有机化合物.     

OH自由基启动异戊二烯光氧化反应时间演化特性的研究?

利用烟雾箱反应装置,开展了OH自由基启动的异戊二烯光氧化生成二次有机气溶胶（SOA）反应的研究。用质子转移质谱仪（PTR-MS）监测反应物异戊二烯浓度、气相产物异丁烯醛和甲基乙烯酮（m/z=70）浓度随反应时间的变化;用扫描电迁移率粒径谱仪（SMPS）监测二次有机气溶胶产生和生长过程;用同步辐射光电离质谱仪（SRPIMS）检测不同反应时刻的光氧化气相产物的质谱。实验数据显示随着反应时间的增长,异戊二烯浓度逐渐减少,主要气相产物的浓度逐渐增加,SOA逐渐产生和增长;当异戊二烯快要消耗完时,SOA仍然继续增长。它表明由于有机气溶胶粒子的产生,主要的气相产物表面上发生的后续反应或者非均相反应产物对SOA的生长具有促进作用。     

固体电解质双功能气体传感器的研制

以sol-gel法合成的NASICON为基体导电层材料,以掺杂C的Cr2O3和ZnO-TiO2分别作为对氨和甲苯敏感的电极材料,制备了一种能同时检测氨和甲苯的新型管式结构固体电解质双功能气体传感器。当工作温度为250~400℃时,传感器对浓度为(50~500)×10–6的氨和(5~50)×10–6的甲苯具有较好的气敏性能,其电动势E值与氨和甲苯浓度的对数呈线性关系,在350℃时,对氨和甲苯的灵敏度分别为–91mV/decade和–60mV/decade。并有较快的响应恢复时间和较好的选择性。     

化学需氧量(COD=Chemical Oxygen Demand)

当水中受到有机物污染时,由于有机物中含有碳。氢而可以被氧化。因此,只要加入强氧化剂(如重铬酸钾,K_2Cr_2O_7),便可以将水样中的有机污染物加以氧化分解,并从所消耗去的氧量而测出已污染“有     

质子转移反应质谱检测不同品种桂花挥发性有机物

为了研究金桂、银桂和丹桂释放的挥发性有机物特征,利用自制的质子转移反应质谱分别检测金桂、银桂和丹桂中的挥发性有机物.在三种漂移管电压(250V、320 V和461 V)下分别获得了金桂、银桂和丹桂的特征全谱图.研究表明金桂的特征产物离子有m/z=171、105、91、87、73和69,银桂的特征产物离子有m/z=120、105、91、77、73和69,丹桂的特征产物离子有m/z=137、73、69和51.通过比较分析发现三种桂花有共同特征产物离子,但不同品种桂花的特征离子及其强度存在一定的差异性.实验结果表明该仪器可以实现快速检测,利用特征产物离子可对不同品种的桂花进行鉴别.质子转移反应质谱技术已应用于环境监测领域,实验结果对开展环境气体监测研究具有一定的参考意义.     

有机物沉积质量对溶胶凝胶减反膜性能的影响规律

真空环境中高功率激光装置光学元件表面的有机物污染是限制其负载能力的原因之一。针对装置中常见的有机物污染和三倍频激光溶胶凝胶减反膜，通过精确控制真空环境中污染源的挥发扩散，制备了有机物质量面密度不同的元件表面，定量研究了有机污染物质量面密度对溶胶凝胶减反膜光学性能及损伤特性的影响规律。实验结果表明：样品表面粗糙度、透过率、损伤阈值等的变化量均与有机物质量面密度成正相关。有机污染物沉积量较少时，由于膜层孔隙被填充，膜层的表面粗糙度略有减小；随着沉积量增加，有机物附着影响表面形貌，粗糙度显著增加。溶胶凝胶减反膜在351 nm波长处的光学透过率随着有机物质量面密度的增加而逐渐降低，这与有机物分子改变溶胶凝胶膜孔隙填充比有关。样品表面的激光损伤阈值变化量和损伤面积随着有机物质量面密度的增加而增加，而且不同有机物沉积量的光学表面的损伤形貌存在显著差异。基于实验结果讨论了有机物影响溶胶凝胶减反膜性能的机理，并探讨了高功率激光系统的洁净度控制方法。     

气动CO_2激光器小信号增益的实验研究

用放大法测量了分别在甲苯和乙醇两种液体燃烧驱动下气动CO2 激光器的小信号增益系数。实验发现 ,用甲苯作为燃料时激光器的平均小信号增益系数可达 0 .62m- 1,远远高于乙醇作燃料时的小信号增益系数。结合甲苯和乙醇分别与空气燃烧后产物组分的配比 ,对实验结果进行了分析 ,得出甲苯是燃烧驱动气动CO2 激光器的一种比较理想的燃料     

气动CO2激光器小信号增益的实验研究

用放大法测量了分别在甲苯和乙醇两种液体燃烧驱动下气动CO2激光器的小信号增益系数。实验发现,用甲苯作为燃料时激光器的平均小信号增益系数可达0.62m-1,远远高于乙醇作燃料时的小信号增益系数。结合甲苯和乙醇分别与空气燃烧后产物组分的配比,对实验结果进行了分析,得出甲苯是燃烧驱动气动CO2激光器的一种比较理想的燃料。     

光照对柠檬烯臭氧氧化产生二次有机气溶胶的影响

作为一种重要的生物源挥发性有机物,柠檬烯的臭氧氧化是大气环境中二次有机气溶胶(SOA)的重要来源之一.基于实验室烟雾箱模拟系统,研究了紫外光照对柠檬烯臭氧氧化形成SOA的影响.实验分别对无光照(即“暗反应”)和有光照条件下反应前体物的消耗、SOA的质量浓度以及SOA的粒径分布随时间的变化等进行了实时探测,并结合气粒分配模型对产率进行了分析.研究结果表明在相应的实验条件下,紫外光照会导致SOA产率下降10％～16％,而气相氧化阶段相关中间产物或者最终产物的光化学反应可能是导致产率下降的重要原因之一.     

NH3 对二甲苯光氧化形成二次有机气溶胶的影响

二甲苯是一种重要的人为源 VOC, 也是城市地区 SOA 的重要前体物。二甲苯光氧化形成的 SOA 受多种环 境因素影响, 而 NH3 对该反应形成的 SOA 生成产率及反应机制的影响尚不清楚。基于室内烟雾箱模拟系统, 探讨了 NH3 对二甲苯光氧化形成 SOA 质量浓度、物理特性及化学组成的影响。研究表明, 在低浓度条件下, NH3 对二甲苯 光氧化生成 SOA 具有明显的促进作用, 结合气溶胶质谱结果发现 NH3 促进醛酮类物质进入颗粒相以及含氮有机物的 生成是导致 SOA 质量浓度增加的主要原因。此外, NH3 能够提高邻二甲苯生成 SOA 的吸光度, 但是对对二甲苯无明 显影响。分析表明, 相较于对二甲苯, 邻二甲苯光氧化会生成大量醛类物质, NH3 与醛类发生美拉德反应是导致 SOA 吸光性增加的主要原因。     

Effective technology for processing industrial volatile organic compounds by the atmospheric pressure microwave plasma torch

In this study, we investigated the abatement of volatile organic compounds (VOCs) by the atmospheric pressure microwave plasma torch (AMPT). To study the treatment efficiency of AMPT, we used the toluene and water-based varnish to simulate VOCs, respectively. By measuring the compounds and contents of the mixture gas before/after the microwave plasma process, we have calculated the treatment efficiency of AMPT. The experiment results show that the treatment efficiency of AMPT for toluene with a concentration of 17.32×10⁴ ​ppm is up to 60 ​g/kWh with the removal rate of 86%. For the volatile compounds of water-based varnish, the removal efficiency is up to 97.99%. We have demonstrated the higher potential for VOCs removal of the AMPT process.     

Effect of component interactions on the removal of organicimpurities in ultrapure water systems

The interaction among the components of the ultrapure water systems in semiconductor plants is explored. Two important examples of these interactions are investigated: interactions of ultraviolet (UV) radiation units with membrane filters and interactions of UV with ion-exchange units. Both experimental and theoretical techniques are developed to study these interactions. The results indicate that the sequencing of UV and filter units affect the efficiency of total oxidizable carbon (TOC) removal. In particular, the efficiency is higher when the filter is before UV. Interaction between UV and ion exchange is desirable for the removal of recalcitrant, low-molecular-weight organic compounds such as ethanol, but undesirable for the removal of high-molecular-weight charged compounds such as bacterial lipopolysaccharides, alginic acids, humic acids, methionine, and glycine     

Preparation of Highly Ordered Nitrogen‐Containing Mesoporous Carbon from a Gelatin Biomolecule and its Excellent Sensing of Acetic Acid

Novel nitrogen‐containing mesoporous carbon with well‐ordered pores (NMC‐G) and high basicity is synthesized using a low‐cost single‐molecule precursor, gelatin biomolecule, and SBA‐15 as a template via nanocasting method. The obtained materials are thoroughly characterized. It is found that the prepared materials have excellent textural properties such as high specific surface areas, huge pore volumes, and large pore diameters. The pore diameter of the materials can also be controlled with a simple adjustment of the pore diameter of the hard templates. The C/N ratio of the samples is calculated to be ≈6.01, which is slightly higher than that observed for mesoporous carbon nitride samples. X‐ray photoelectron spectroscopy (XPS) reveals the presence of sp² hybridized carbon in aromatic ring structure attached to amino groups. The materials could adsorb a huge quantity of CO₂. The sensing capability of the materials with different pore diameters for different adsorbates including ethanol, acetic acid, aniline, toluene, and ammonia is also investigated. Among the materials with different pore diameters studied, the material with the highest basicity and the largest pore diameter (NMC‐G‐150) showed excellent sensing performance with a high selectivity of adsorption for acetic acid molecule.     

Preparation of Hollow Silica Nanospheres by Surface‐Initiated Atom Transfer Radical Polymerization on Polymer Latex Templates

Poly(vinylbenzyl chloride), (PVBC) latex particles of about 100 nm in size are prepared by emulsion polymerization. Silyl functional groups are introduced onto the PVBC‐nanoparticle templates via surface‐initiated atom transfer radical polymerization of 3‐(trimethoxysilyl)propyl methacrylate. The silyl groups are then converted into a silica shell, approximately 20 nm thick, via a reaction with tetraethoxysilane in ethanolic ammonia. Hollow silica nanospheres are finally generated by thermal decomposition of the PVBC template cores. Field‐emission scanning electron microscopy and field‐emission transmission electron microscopy are used to characterize the intermediate products and the hollow nanospheres. Fourier‐transform infrared spectroscopy results indicate that the polymer cores are completely decomposed.     

Highly Emitting Neutral Dinuclear Rhenium Complexes as Phosphorescent Dopants for Electroluminescent Devices

A series of neutral, dinuclear, luminescent rhenium(I) complexes suitable for phosphorescent organic light emitting devices (OLEDs) is reported. These compounds, of general formula [Re₂(µ‐Cl)₂(CO)₆(µ‐1,2‐diazine)], contain diazines bearing alkyl groups in one or in both the β positions. Their electrochemical and photophysical properties are presented, as well as a combined density functional and time‐dependent density functional study of their geometry, relative stability and electronic structure. The complexes show intense green/yellow emissions in toluene solution and in the solid state and some of the complexes possess high emission quantum yields (? = 0.18–0.22 for the derivatives with disubstituted diazines). In butyronitrile glass, at 77 K, due to the charge transfer character of the lowest (emitting) excited state, strong blue shift of the emission is observed, accompanied by a strong increase in the lifetime values. The highest‐performing emitting complex, containing cyclopentapyridazine as ligand, is tested in a polymer‐based light‐emitting device, with poly(9‐vinylcarbazole) as matrix, as well as in a device obtained by vacuum sublimation of the complex in the 2,7‐bis(diphenylphosphine oxide)‐9‐(9‐phenylcarbazol‐3‐yl)‐9‐phenylfluorene (PCF) matrix. This represents the first example of devices obtained with a rhenium complex which can be sublimed and is solution processable. Furthermore, the emission is the bluest ever reported for electrogenerated luminescence for rhenium complexes.     

Emerging Chemistry in Enhancing the Chemical and Photochemical Stabilities of Fused-Ring Electron Acceptors in Organic Solar Cells

The power conversion efficiency of organic solar cells (OSCs) has made exceptionally rapid progress in the past five years owing to the emergence of fused-ring electron acceptors (FREAs). To achieve the commercialization, it is urgent to resolve the stability issues of OCSs from materials to devices. In particular, the state-of-the-art FREAs, often synthesized by Knoevenagel condensation, generally contain two exocyclic vinyl groups (CC bond) as the conjugated bridges, which inevitably exhibit an obvious electron-deficient characteristic due to the strong push-pull electronic effect. As a result, these vinyl bridges are vulnerable to nucleophile attacking and/or photooxidation, leading to poor chemical and photochemical stabilities of FREAs that easily cause the degradation of device performance. In this perspective, an in-depth understanding of the degradation mechanism of FREAs is provided, and then effective strategies reported recently are reviewed for improving the chemical and photochemical stabilities of FREAs from interfacial engineering to molecular engineering to additive engineering. Finally, a conclusion and outlook for the future design of highly efficient and stable FREAs are also presented.