New derivatization method for determination of 3-chloro-4(dichloromethyl)-5-hydroxy-2(5H)-furanone in water

An extremely potent mutagen, 3-chloro-4(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) is commonly present in chlorinated drinking water. Due to its high mutagenic activity and according to World Health Organization guidelines its concentration should be controlled in drinking waters. Determination of MX is difficult due to ppt levels at which the compound usually exists in drinking waters. Derivatization of MX with 2-propanol is presented as a method which significantly lowers the GC–MS detection level compared to other alcohol derivatization agents.     

Synthesis of hexacarbonyldiiron complexes from azines of the aromatic series

Conclusions A preparative method for the synthesis of binuclear hexacarbonyldiiron complexes from aromatic azines and Fe₃(CO)₁₂in cyclohexane solutions in the presence of carbonyls of group VIb as catalysts has been proposed.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 418–422, February, 1982.     

Hypernuclear production in the (K, π) reaction

Cross sections for the production of hypernuclei were measured in the reaction A(K⁻, π⁻) _ΛA. on light and heavy nuclear targets, using a separated K⁻ beam at the CERN Proton Synchrotron. The pions were detected in the forward direction. The results are compared with cross sections calculated under the assumption that the reaction took place on a single neutron. The good agreement between the measured and the calculated cross sections justifies the use of the (K⁻, π⁻) reaction in order to obtain spectroscopic information on hypernuclei.     

Fabrication of high-aspect-ratio microstructures using excimer laser

An excimer laser micromachining system is developed to study the ablation of high-aspect-ratio microstructures. The study examines the ablation efficiency, specifically, the impact of changing major laser operating parameters on the resulting microstructural shapes and morphology. The study focuses on glass, although results on silicon and aluminum are also included for comparison. In ablating grooved structures, the ablation depth has been observed to be linearly proportional to the operating parameters, such as the pulse number and fluence. The results specifically indicate that ablation at low fluence and high repetition rates tends to form a V-shaped cross-section or profile, while a U-shaped profile can be obtained at high fluence and low repetition rate. The ablation rate or ablated volume has then been quantified based on the ablation depth measured and the ablated profile observed. The threshold fluence has also been obtained by extrapolating experimental data of ablation rate. The extrapolation accuracy has been established by the good agreement between the extrapolated value and the one predicted by Beer's law. Moreover, a one-dimensional analytical solution has been adopted to predict the ablated volume so as to compare with the experimental data. The reasonable agreement between the two indicates that a simple analytical solution can be used for guiding or controlling further laser operations in ablating glass structures. Finally, the experimental results have shown that increasing the repetition rate favors the morphology of ablated surfaces, though the effect of repetition rate on ablation depth is insignificant.     

Spectroscopic studies of 5,5′-dimethoxy-3,3,′-disulfobutyl-9-ethylthiacarbocyanine (DDTC) in solutions and immobilized in sol-gel matrices

Absorption spectra of 5,5′-dimethoxy-3,3,′-disulfobutyl-9-ethylthiacarbocyanine (DDTC) in aqueous solutions and immobilized in xerogels prepared by the sol-gel method were obtained. Influence of pH, detergent (Triton X-100), ethanol addition and sol-gel preparation method on the dye aggregation equilibria and its photostability were investigated. In liquid solutions lowering of pH, as well as addition of the detergent, shift the aggregation equilibrium towards the DDTC monomeric form. However, while more acidic conditions result in a decrease of the dye stability, addition of the detergent has a slightly stabilizing effect on the dye. However, addition of ethanol drastically reduces the DDTC photodecomposition and shifts the aggregation equilibrium towards the dye monomer. Entrappment of the thiacarboxycyanine in sol-gel matrix does not prevent the bleaching although the entrapped dye displays significantly increased stability. Lowering of temperature and keeping the doped xerogels in the dark further retards the immobilized dye bleaching and dimer formation.     

外延定向生长氧化铌模型催化剂的制备

为用现代表面科学技术研究金属氧化物催化剂，在Pt（111）上于超高真空系统中原位蒸镀制备了NbO、NbO2、NbO2、单晶薄膜（＞2nm）．通过AES、ISS、LEED、ILS等手段研究了单晶薄膜的成长模式、化学计量和几何结构．表明通过选择合适的废物和控制制备条件，可制备出确定结构的金属氧化物单晶薄膜表面作为体相氧化物催化剂的模型表面．这种方法克服了电子能谱技术研究金属氧化物表面的困难，为研究金属氧化物催化剂的表面化学物理性质提供了方法