流动VLBI站氢原子钟的研制与性能测试

氢脉泽是射电天文所必需的频率标准.文中对为流动vLBI站研制的新一代氢脉泽的物理结构特点进行了讨论，包括对腔泡结构、磁屏蔽、原子束光学系统等.同时性能测试表明在80秒到1天之间频率稳定度优于1×10     

ISOLATION, PURIFICATION AND CHARACTERIZATION OF THE HYDROGEN EVOLUTION PROMOTING FACTOR OF HYDROGENASE OF SPIRULINA PLATENSIS

A component (s-factor) with obvious promoting effect on hydrogen evolution of hydrogenase has beenisolated and extracted from a Cell=free preparation of Spirulina platensis.The effect of the s-factor in the re-action system is similar to that of Na_2S_2O_4, but is coupled with ligh. The s-factor has the maximumabsorption peak at 620 nm in the oxidized state, at 590 nm in the reduced state. The partially purifieds-factor showed two bands by SDS-PAGE and is distinctly different from phycocyanin,which has nochange of oxidized state and reduced state absorption spectra, and also has no promoting effect onhydrogenase of Spirulina platensis under the light.     

A numerical investigation of the destruction of peroxy radical by Cu ion catalysed reactions on atmospheric particles

To determine if Cu mediated reactions on atmospheric particles are important to HO₂ chemistry in the ambient atmosphere, Cu molalities were calculated from measured Cu aerosol particle concentrations, mass and number size distribution data from a site in central Sweden. A comparison of characteristic times indicates that at low relative humidities the reaction is limited by the mass transport of gas phase HO₂ to the particle surface and not by the chemical kinetics of the aqueous reaction. Comparison of half-lives for particle reactions and the gas phase destruction of HO₂ to form H₂O₂ indicate that heterogeneous reactions on aerosol particles may have important consequences on the chemistry of HO₂ and H₂O₂ in the troposphere.     

蒸发皿中水面蒸发氢氧同位素分馏的实验研究

气象要素与蒸发密切相关,通过室内外不同气象条件下的器皿水蒸发实验,获得了水面蒸发氢氧稳定同位素分馏因子与气象要素的关系。实验结果表明,随着蒸发的进行,剩余水体中逐渐富集重同位素;自由水体蒸发同位素分馏在垂线上有分层现象,表层水体同位素值比垂线平均的同位素值略富集;不同温度条件下的室内蒸发实验中,温度越高,液-气间分馏系数越小,相应于同一剩余水体体积比,剩余水体稳定同位素值则越低。室外器皿水自由蒸发实验中得出的蒸发线方程斜率较大地偏离了当地降水线,表明实验期间水体蒸发分馏作用较明显。该研究为进一步揭示水体蒸发分馏规律提供了可靠的实验依据。     

青藏高原东缘缅萨洼金矿成矿流体地质地球化学特征

缅萨洼金矿位于中国中轴构造带的中南段,青藏高原的东缘,赋存于金河-箐河断裂带次级断裂羊坪子韧性剪切带中本文根据对该矿床硫化物流体包裹体的氦氩同位素、硫化物的硫同位素以及与硫化物共生的石英的流体包裹体特征、成分以及氢氧同位素组成的测定,讨论了缅萨洼金矿的成矿流体来源及其矿床成因。结果显示,该矿床硫化物流体包裹体中的3He/4He变化较小,为0.69-0.82,显示了地幔流体参与成矿作用的可能性。而4He的含量变化范围较大,一般在2.19-10.62×10-6cm3STP/g(方铅矿除外)与3He/4He相比,40Ar/36Ar的比值则变化较小,一般为251-509。而硫化物的δ34S同位素变化范围在-1.8-2.2‰,平均值为0.5‰,说明硫的地幔来源。与硫化物共生的石英的流体包裹体的类型主要有富液相的盐水溶液包裹体、富气相的盐水溶液包裹体、三相CO2包裹体、纯液相CO2包裹体以及有机流体包裹体。成矿流体的氢氧同位素则显示成矿流体来源于岩浆水(或地幔流体)与大气降水的混合流体,本文认为,缅萨洼金矿的成矿流体为地幔流体与大气降水的混合流体,是渐新世印度大陆与亚洲大陆碰撞之后,该地区大规模走滑与剪切作用过程中,局部伸展作用的产物。     

极地冰雪氢氧同位素指标及其指示意义

本文综述了水汽来源状况、降水季节变化、火山喷发、太阳活动等气候环境因素对极地冰雪中同位素含量的可能影响及其程度 ,以及降水区域不均衡性、降水年际不均衡性、逆温层和同位素在冰雪中的扩散迁移作用等几种不稳定因素可能对冰雪同位素分析造成的干扰 ;在此基础上 ,综述了极地冰雪中δ1 8O、δD和其差值d(d =δD - 8δ1 8O)与局部或全球气温之间的一些线性关系 (包括全球尺度 ,格陵兰地区 ,南极地区等 )及它们在空间分布上的变化规律     

金刚石中分子氢的赋存状态研究

金刚石中分子氢的定向红外光谱研究表明在垂直于(100),(110)和(111)三个方向上所测得分子氢的浓度是不相同的,且不同样品中的变化趋势也不同,即分子氢在金刚石中的定向性不明显;MNDO法计算结果显示分子氢在金刚石中的稳定程度大小关系依次为沿〈111〉定向的键心与反键心组合(a.b+b.c)〉六角体空隙(H)〉四面体空隙(T1)〉菱形中心(C1＝C2)〉四面体空隙(T2).     

水电解制氢设备在使用中应注意的问题

介绍GX-2型水电解制氢设备在使用过程中,对电解液的配制与氢气纯度分析应注意的问题。     

Diurnal Variations of Atmospheric Hydrogen Peroxide Concentrations in Saxony (Germany)

During a 3-year study, gaseous hydrogenperoxide (H₂O₂) concentrations were measuredas part of the SANA project at the Melpitz FieldResearch Station and in the city of Leipzig. Typicaldaily mean H₂O₂ mixing ratios on sunny dayswere 0.15 to 0.25 ppbv with maximum values of 0.3 to0.5 ppbv at Melpitz, and 0.3 to 0.6 ppbv with maximumvalues of 0.4 to 1.0 ppbv in Leipzig. Over the entireperiod of the project the maximum hourly mean valueswere 2.1 ppbv and 5.3 ppbv in Melpitz and Leipzig,respectively. The data were not complete enough to show a trend.Linear regression analysis shows, that ozone(O₃), temperature and solar radiation arepositively correlated with H₂O₂, whereasnitrogen oxides (NO_x), carbon monoxide (CO) andrelative humidity are negatively correlated. Negativecorrelation between H₂O₂ and CO is caused byjoint occurrence of CO with NO_x in exhaust gases.Negative correlation between H₂O₂ andrelative humidity is not necessarily in contradictionto the accelerating effect of water vapour onH₂O₂ formation. The strong positivecorrelation of H₂O₂ with the dew pointdifference however seems to better reflect theinfluence of water vapour. Multiple linear regression analysis (MLRA) of thecomponents measured, indicates the great influence of CO on the formation of H₂O₂ in the gasphase.