ESTIMATION OF VOLATILE SULPHUR COMPOUNDS IN BEER

A method has been developed for the quantitative estimation of volatile sulphur compounds in beer at levels below 0.1 μg litre^?1. The method relies on the concentration of beer headspace volatiles onto a porous polymer followed by injection into a capillary gas chromatographic column using a thermal desorption cold trap injector. The volatile components are separated using temperature programming and detected by a flame photometric detector specific for sulphur compounds. The mean concentrations and the estimates of r₉₅ (μg litre^?1) for volatile sulphur compounds measured in a commercial lager were respectively: methanethiol (0.33, 0.30); dimethyl sulphide (19.3, 5.3); carbon disulphide (0.42, 0.32); ethylene sulphide (0.37, 0.05); 1-propanethiol (0.11, 0.02); methyl thioacetate (11.7; 2.7); methyl disulphide (0.34, 0.42). The method is a significant improvement over previous techniques for the quantification of sulphur-containing volatiles in beer .     

Preparation of large-area high-quality YBCO thin films by pulsed laser deposition with Si heater and composite scanning of laser and target

We report on the successful preparation of large-area high-quality YBa₂Cu₃O₇ superconducting thin films by pulsed excimer laser ablation with a Si heater and composite scanning of laser beam and target. The Si heater, composite scanning of laser beam and target, and experiment results are described. The temperature variation of the Si heater was < ±0.5% in a 45×40 mm² area of 900–1000 °C. Films were deposited on LaAlO₃ substrates 35 mm in diameter. The thin films exhibited a thickness variation of ±2.5%; the superconducting properties wereT _c0=91×0.5 K andJ _c= (3.3±0.7)×10⁶ A/cm² at 77 K and zero magnetic field.     

脉冲激光重复烧蚀石墨的反应性光声谱

利用脉冲ＮｄＹＡＧ激光器对石墨进行重复性烧蚀。在一定的激光能量下，激光光声强度随重复次数增加而衰减。表明烧蚀坑对能量和质量从样品中流出有抑制作用。     

脉冲激光诱导液—固界面反应制备金刚石纳米晶

采用液体水中激光熔蚀固体石墨靶的方法，制成晶形较好的六方金刚石相和立方金刚石，还观察到一种柱状纳米金刚石晶体。     

反应脉冲激光淀积硫化铅膜的SEM和XPS研究

以扫描电镜和Ｘ射线光电子能谱等多种测试手段研究分析了用反应脉冲激光淀积技术制备的ＰｂＳ薄膜。分析结果表明，利用该淀积方法可以得到附着力好，符合化学计量比的硫化铅薄膜。     

Coupled Ablation and Heat Transfer Analysis of Lower Head for Reactor Pressure Vessel under Severe Accident Condition

After a reactor core melts accident, the solid wall of the reactor pressure vessel (RPV) will be inevitably eroded by the melting core which contains large density of heat flux. The analysis of the coupled ablation and heat transfer of the lower head for RPV is of great theoretical significance to the effectiveness demonstration of water injection in reactor pit and the confirmation of the residual wall thickness of RPV. In this work, numerical simulations were carried out based on the RPV model of CPR1000 using the CFD software FLUENT 17.2. Based on dynamic mesh model and user-defined function (UDF) redevelopment, a fully coupling calculation model considering the transient ablation and heat conduction of solid wall of RPV, the redistribution of heat flux density in RPV inner wall and the subcooled boiling of RPV outer wall was established. Both two-phase flow pattern in the reactor pit and temperature field of RPV solid wall ablation within 9 000 s were obtained and the minimum residual wall thickness and the occurrence location were determined by analysis. The results show that it is feasible to use dynamic mesh to capture wall ablation. The fully coupling calculation model has certain advantages in analyzing the transient ablation process of RPV under severe accident.     

火电机组火焰检测系统的分析与研究

通过对中储式锅炉、W型火焰燃烧的火电机组火焰检测的基本原理、调整方法以及火焰检测、调整中遇到的问题进行分析与研究,提出一些经验与体会供国内相同类型的机组参考。     

用于火焰探测的紫外光敏管

介绍了用火焰探测紫外光敏管的结构，工作原理和主要技术参数，讨论了紫外光敏管材料及管内工作气氛的选择原则，并对影响紫外光敏管性能参数因素作了讨论。     

Pulsed laser deposition of epitaxial BaxSr1−xTiO3/YBa2Cu3O7 bilayers on LaAIO3 substrates

YBa₂Cu₃O₇/Ba_xSr_1−xTiO₃ bilayers were grown epitaxially on LaA10₃ substrates using the pulsed laser deposition method. A microstructural investigation revealed that all compositions of Ba_xSr_1−xTiO₃ investigated from x = 0 to x = 1 showed (001) orientation and epitaxy across the interface as analyzed by Rutherford backscattering spectroscopy channel yields of < 8% for BaTiO₃ on YBa₂Cu₃O₇ films. Dielectric properties including the dielectric constant, k, and the loss tangent, tan δ, were measured as a function of composition, and it was found that the highest k-values (k = 400) existed for the x = 0.72 composition.