A three-dimensional (3D) photochemical grid model, CAMx-2.0 (1998), was employed to analyze the spatial and temporal variations of ambient ozone during ozone episodes (concentration of ozone > 120 ppbv) in the Kao-Ping airshed in 2000-2001. The sensitivity analyses of ozone concentrations to the emission reductions in volatile organic compounds (VOC) and nitrogen oxides (NOx) were performed, and the relationships between ozone concentrations and meteorological parameters were examined. Furthermore, the transport routes were studies using inverse trajectory method. Examinations of meteorological parameters and ozone trends reveal that warm temperature, sufficient sunlight, low wind, and high surface pressure are distinct parameters that tend to trigger ozone episodes in Kao-Ping area in autumn and winter seasons. Seasonal patterns of surface ozone include a summer minimum with two maxima in autumn and late winter to the middle of spring, consistent with low mixing heights in autumn and winter and large mixing height in summer. Predicted values of hourly ozone concentration agree reasonably well with measured data. The assessment of the effect of the initial and boundary conditions on the performance of the model revealed that the model can be improved by specifying an ozone concentration of 70 ppbv rather than 30 ppbv on the top boundary of the model, while separately considering the daytime and nighttime ozone concentration on the lateral boundary conditions. The sensitivity analysis shows a VOC-sensitive regime in Kaohsiung City. In addition to the locally emitted pollutants, the inverse trajectory analysis shows that most pollutants in Kaohsiung City come from Kaohsiung County, followed by Tainan County and Ping-Tung County. In autumn, the air quality is worst in Ping-Tung County and ozone episodes occur most frequently. Because the prevailing wind is north or north-east wind in autumn, most pollutants are transported from the upwind areas, including Kaohsiung City and Kaohsiung County. The sensitivity analysis shows a NOx-sensitive regime for Ping-Tung city, consistent with Sillman¡¦s results (1999), indicating that freshly emitted pollutants are typically (but not always) characterized by VOC-sensitive chemistry and evolve towards NOx-sensitive chemistry as the air parcels move downwind.

No description available.

No description available.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第20215号 / 理博第4300号 / 新制||理||1618(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 鹿内 利治, 教授 長谷 あきら, 准教授 小山 時隆 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

The synthesis of o-(N,N-dimethylamino)methylphenyl tris (trimethylsilyl) silane (II), a photochemical precursor of o- (N,N-dimethylamino) methylphenyl (trimethylsilyl) sila ammonium ylide (intramolecular silylene complex) and otolyl(trimethylsilyl)silylene is reported. Photolysis of II at room temperature in a cyclohexane solution of triethyl silane produced the silylene ylide and the presumably uncomplexed isomer, a silylene, which is trapped to afford the 2-(o-(N,N-dimethylamino)methylphenyl) -1,1,1-triethyl 3,3,3-trimethyltrisilane, 33% yield. A second decomposition pathway, a photodeamination, produced o-tris(trimethyl silyl) silyltoluene. UV spectra of the silaammonium ylide formed in the photochemical reaction of II was observed at 77k in hard or soft matrices.

No description available.

No description available.

This thesis is a study of the photochemical reactions of 2,7-dimethyloctane.

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy in Chemistry. Johannesburg, 2013 / Unable to load abstract.

Methods for the remotely triggered release of biologically active molecules has been an area of intense research in recent years, as it would allow hard-to-obtain biomolecules to be tested in cell-like environments.1 The removal of polar functional groups from hydrophilic structures upon the application of an external stimulus would generate unfunctionalised molecules, which could then participate in amphiphilic self-assembly. This could be used in the release of bioactive molecules and therefore in the in vitro investigation of drug activity. In this PhD project, diazene chemistry was identified as the optimal method for the generation of unfunctionalised compounds through the removal of polar groups since fragmentation takes place rapidly and without the formation of potentially toxic intermediates or by-products. The synthesis of a range of protected hydrazines is described in this thesis (Scheme 1), in addition to the investigation of the rates of decomposition of various simple sulfonyl hydrazides, which led to the isolation of the product of the decomposition of a sulfonyl hydrazide. The photolysis of NVOC- and NPPOC-protected hydrazine derivatives is discussed.