氢同位素分馏效应校正

同位素分馏效应是影响氢同位素丰度准确测定的主要因素。采用系统校正法和分子泵压缩比校正系数法可以较好地解决分馏效应对氢同位素丰度准确测定产生的影响。系统校正法是用标准样品的标称值对测量系统进行误差修正得到系统误差校正系数k，然后通过C校=kC样测，通过对标准样品的测量给出，校正系数k=C标／C标测，用系统校正法校正分析待测样品的丰度值，需要使用气体同位素标准，而分析不同丰度的氢同位素气体样品，需要使用相应丰度值的气体同位素标准。因此氢同位素标准气体的获取以及在储存过程中保持标称值不变是需要考虑的问题。     

拉曼光谱研究苯-重水间氢同位素分馏效应

应用金刚石压腔结合拉曼光谱技术研究了封闭体系内氢同位素在苯和重水之间的分馏效应。物相间达到同位素交换平衡是测定稳定同位素分馏系数的前提。与高温高压条件下水抑制正烷烃、环烷烃等烷烃的氢同位素分馏不同,苯的特殊结构可促使其在实验条件下与重水发生氢同位素分馏。通过逐步升高体系温度、增大苯和重水的接触面积、300 ℃下恒温足够长时间等实验手段促使苯和液态重水间达到氢同位素交换平衡,测得300 ℃条件下苯和重水之间的氢同位素分馏系数为0.909 9。证明了原位拉曼技术测定不同液相间氢同位素分馏系数的可行性,同时扩展了金刚石压腔结合拉曼光谱技术测定不同物相间稳定同位素分馏系数的应用范围。     

大容量贮氘氚铀床的研制

为了满足重水提氚中大量氘氚气体的安全贮存与转运，设计并加工了大容量氘氚铀床并对其进行了贮氘氚性能的测试。     

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对所研制的质谱测量与分析系统进行了性能测试。烘烤后系统的极限真空达到了7.3×10-7Pa,总漏气率为3.84×10-9Pa.m3.s-1。上下球室之间的气体压力,以及漏孔的漏气率与高分辨四极质谱计的氦分压力均呈现了良好的线性关系。结果满足动态流导法真空校准的技术要求,为氘、氦混合气体的测量与分析提供了条件。     

靶丸内混合气体的质谱法测量技术

 叙述了四极质谱(QMS)的结构和气体分析质谱(GAM)的定量分析工作原理。四极质谱具有快速扫描响应，较高的响应灵敏度的特点，在经过标准气体校准后，加上独特的气体进样系统，可用于惯性约束聚变(ICF)靶丸内混合气体组分含量及总量的定量分析。同时，在经过坐标尺度放大等手段，可以对混合气体中质量数极为接近的氘(4.028 2)和氦(4.002 6)在高分辨模式下进行基线分离。用四极质谱对各种靶丸结构、不同混合气体种类的气体进行了定量组分分析，为ICF实验用靶提供了同批次实验数据。     

氢同位素氘从气相到液相的催化交换实验

在自行建立的气-液催化交换装置上，用氢同位素氘代替氚研究了氘从气相到液相的催化交换过程。实验装置的流程图见图1。主要由催化交换柱、气体流量计、料液泵、贮液槽及控制系统组成。     

2H NMR研究分子中氢同位素氘分布

²H NMR测定了酒中氢同位素氘的分布。发现随水质不同氘含量将变化;且在亚基甲中氘含量变化幅度大。而由不同原料酿造的酒的氘含量的区别主要表现在甲基上的变化。因而获得用²H NMR监测化合物质量及探究生化机制有意义的方法。     

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介绍了为开展漏孔检测、氘-氦分辨性能及真空检漏技术等相关实验研究而进行的四极质谱计分析与测量系统的研制,描述了真空室结构、抽气设备的选型、测量仪器的选择及控制保护子系统工作方式。对系统进行了包括极限真空、残余气体质谱分析、漏放气率、质谱计性能等测试,结果表明本系统达到了设计要求。     

高压氘氚靶球的制备与拉曼光谱研究

氢同位素的定量分析与监测在能源与环境领域都有着重要的意义。激光拉曼光谱由于其可以无损分析氢同位素分子,已经成为一种重要的方法,在国际热核聚变实验反应堆(ITER)和美国萨凡纳河工厂得到了广泛应用。利用高压充气装置得到了惯性约束聚变(ICF)高压靶丸,并对靶丸内气体进行原位拉曼光谱测量,通过对高压下氘氚混合气体的拉曼光谱进行分析得到了靶丸内气体的成分比例,验证了靶丸充气工艺参数。实验表明,在CCD的积分时间延长到1 min时,氘(DD),氘氚(DT)和氚(TT)的测量精度可以达到1%,同时对不同时刻靶丸内气体组分的拉曼光谱进行测量,实验结果表明在氘氚渗透和氚衰变两者共同作用下,靶丸内总气体压力随时间不断下降,但是气体组成基本不发生变化。     

高分辨等离子体质谱法测定高纯二氧化钛中痕量杂质

采用高分辨电感耦合等离子体质谱(HR-ICP-MS)法同时测定高纯二氧化钛中26种杂质元素。样品用硫酸铵和浓硫酸分解后,在高分辨质谱测量模式下避免了大量的质谱干扰。详细地研究了高浓度钛和硫酸的基体效应,讨论和确定了实验的最佳测定条件,应用标准加入法进行定量分析。结果表明,方法的检出限为0.004～0.63 μg·g-1,回收率为87.6%～106.4%,相对标准偏差(RSD)小于3.5%。方法准确、快速、简便,应用于高纯二氧化钛中杂质元素的测定,满意结果。     

The isotope altitude effect reflected in groundwater: a case study from Slovenia

This paper presents the stable isotope data of oxygen (δ¹⁸O) and hydrogen (δ²H) in groundwater from 83 sampling locations in Slovenia and their interpretation. The isotopic composition of water was monitored over 3 years (2009–2011), and each location was sampled twice. New findings on the isotopic composition of sampled groundwater are presented, and the data are also compared to past studies regarding the isotopic composition of precipitation, surface water, and groundwater in Slovenia. This study comprises: (1) the general characteristics of the isotopic composition of oxygen and hydrogen in groundwater in Slovenia, (2) the spatial distribution of oxygen isotope composition (δ¹⁸O) and d-excess in groundwater, (3) the groundwater isotope altitude effect, (4) the correlation between groundwater d-excess and the recharge area altitude of the sampling location, (5) the relation between hydrogen and oxygen isotopes in groundwater in comparison to the global precipitation isotope data, (6) the groundwater isotope effect of distance from the sea, and (7) the estimated relation between the mean temperature of recharge area and δ¹⁸O in groundwater.     

Stable isotope study of precipitation and cave drip water in Florida (USA): implications for speleothem-based paleoclimate studies

Stable isotopes of hydrogen and oxygen were used to examine how the isotopic signal of meteoric water is modified as it travels through soil and epikarst into two caves in Florida. Surface and cave water samples were collected every week from February 2006 until March 2007. The isotopic composition of precipitation at the investigated sites is highly variable and shows little seasonal control. The delta18O vs. delta2H plot shows a mixing line having a slope of 5.63, suggesting evaporation effects dominate the isotopic composition of most rainfall events of less than 8 cm/day, as indicated by their low d-excess values. The delta18O values of the drip water show little variability (<0.6 per thousand), which is loosely tied to local variations in the seasonal amount of precipitation. This is only seen during wintertime at the Florida Caverns site. The lag time of over two months and the lack of any relationship between rainfall amount and the increase in drip rate indicate a dominance of matrix flow relative to fracture/conduit flow at each site. The long residence time of the vadose seepage waters allows for an effective isotopic homogenisation of individual and seasonal rainfall events. We find no correlation between rainfall and drip water delta18O at any site. The isotopic composition of drip water in both caves consistently tends to resemble the amount-weighted monthly mean rainfall input. This implies that the delta18O of speleothems from these two caves in Florida cannot record seasonal cycle in rainfall delta18O, but are suitable for paleoclimate reconstructions at inter-annual time scales.dagger.     

Nickel/Chromium oxide/Zirconium oxide Catalysts for Hydrogen/Deuterium Isotopic Exchange

Catalysts composed of nickel and promoted with different metal oxides proved to be suitable for H/D isotropic exchange between hydrogen and water vapour. They loss their activity due to water condensation on their surfaces. Several nickel/chromium oxide/zirconium oxide catalysts of different composition were prepared by the coprecipitation technique. The liquid phase activity of these catalysts were followed using the hydrogen peroxide decomposition on their surfaces at different temperatures. The surface characteristics of the examined catalysts were followed by applying the BET method. The results were discussed and lead to the required catalyst composition which resists the water condensation on its surface during operation and has relatively high activity in the vapour phase H/D isotopic exchange reaction between hydrogen and water.     

金刚石压腔结合拉曼光谱技术进行氢同位素分馏的实验研究

应用水热金刚石压腔结合拉曼光谱技术来进行石膏和重水间稳定同位素分馏的实验研究.氢同位素 D 与 H 的质量差百分比是所有稳定同位素里最大的,由质量引起的分馏更容易发生,更容易在实验中观测;石膏是浅部地壳重要的含水矿物,它与重水之间的同位素分馏效应对矿物-水体系的同位素平衡分馏研究具有重要意义.常用分馏系数是指两矿物或两...     

低阶煤热解结构演化及与烷烃气碳同位素相关性的红外光谱

为了阐释煤热解过程中结构演化与烷烃气碳同位素的关系,进行了低阶煤在高压釜密闭体系下热解实验,分析热解烷烃气碳同位素组成;借助傅里叶红外光谱(FTIR)精细剖析了煤结构演化规律,构建了烷烃气碳同位素组成与结构演化的关系模型,揭示了热解烷烃气碳同位素变化的原因。结果显示在R_{o, max}＜1.3%之前的阶段,煤中脂链轻碳同位素被分馏出去而重碳同位素被留在长链中;当1.3%＜R_{o, max}＜2.0%时, 具有相对较重碳同位素组成脂链再进一步的断裂分解仍主导了烷烃气碳同位素变化,也即是R_{o, max}在2.0%之前的阶段,煤中脂链倾向性的裂解方式是烷烃气碳同位素变化的主要因素;此后(R_{o, max}＞2.0%)由于芳环缩聚和解体进程的加剧使得环内重碳物质得以释放进入烷烃气中,而导致其碳同位素组成迅速变重。热解烷烃气中甲烷和乙烷碳同位素组成与煤脂链结构演化呈现同步性特征,δ13C_CH4和δ13C_C2H6值可以作为煤脂链结构演化的敏感性指标。R_{o, max}=1.3%和2.0%是煤热解结构演化与烷烃气碳同位素组成关联性的重要节点。研究成果对探索煤生烃与结构演化的耦合关系及二次生烃机理有理论意义。     

Distribution of stable isotopes in surface water along the Danube River in Serbia

Stable hydrogen and oxygen isotopes were analysed in water samples from the River Danube and its tributaries during a longitudinal survey performed in August 2005 on Serbian territory. Danube river water data ranged from-80 per thousand to-66 per thousand for delta2H, and from-11.2 per thousand to-9.3 per thousand for delta18O with delta values increasing downstream. The isotopic signatures of the adjacent tributaries (the Tisza, the Sava and the Velika Morava) sampled at the locations close to their confluence with the Danube (Titel, Ostruznica and Ljubicevski most, respectively) just about the time of the campaign were enriched (-67 per thousand and-63 per thousand for delta2H, and-9.3 per thousand and-8.9 per thousand for delta18O) with respect to the Danube water because of their catchment effects. Hydrogen and oxygen stable isotope values were used in combination with measured physico-chemical and biological parameters to trace hydrological and transport processes in these river systems. The mixing relationships between the Danube main stream and its tributaries were estimated using the mass balance for isotopic composition and electrical conductivity as conservative parameters. Evidence of an incomplete mixing process at the Centa location, 8 km below the confluence of the Tisza river, with its participation of 88% was shown by its oxygen-18 content. The correlations between river water isotope composition and physico-chemical and biological parameters are discussed.     

Stable Isotope Geochemistry of Antarctic Salt Efflorescences

Salt efflorescences consisting of gypsum sampled mainly in the Schirmacher Oasis have been analyzed for the isotopic composition of the water of crystallization and of the sulphate-sulphur. For comparison, a few samples from other Antarctic locations (Guettard Range, Prince Charles Mts., Insel Mts.) were included in the study. The isotopic variations of the water of crystallization of secondary gypsum and the calculated isotopic composition of the mother solution reflect the local climatic conditions during the precipitation of the efflorescences. It is therefore possible to obtain qualitative information about the climatic conditions prevailing in the studied region.     

Defining a stable water isotope framework for isotope hydrology application in a large trans-boundary watershed (Russian Federation/Ukraine)

Stable isotopes of hydrogen (²H) and oxygen (¹⁸O) of the water molecule were used to assess the relationship between precipitation, surface water and groundwater in a large Russia/Ukraine trans-boundary river basin. Precipitation was sampled from November 2013 to February 2015, and surface water and groundwater were sampled during high and low flow in 2014. A local meteoric water line was defined for the Ukrainian part of the basin. The isotopic seasonality in precipitation was evident with depletion in heavy isotopes in November–March and an enrichment in April–October, indicating continental and temperature effects. Surface water was enriched in stable water isotopes from upstream to downstream sites due to progressive evaporation. Stable water isotopes in groundwater indicated that recharge occurs mainly during winter and spring. A one-year data set is probably not sufficient to report the seasonality of groundwater recharge, but this survey can be used to identify the stable water isotopes framework in a weakly gauged basin for further hydrological and geochemical studies.     

Isotopic Exchange of Hydrogen between the Fluids of the Hydrocarbon Fields

It is presented the isotopic exchange of hydrogen in natural gas, crude oil, and underground water. The general behaviour of the isotopic exchange occuring in a system with a large number of components is given. A good agreement between the calculated and the experimental isotopic distribution factors is obtained in the case of the isotopic exchange of hydrogen between methane and underground water. The deuterium concentration of the crude oil samples inserts between the values obtained for methane and underground water. This fact is due to the presence of the isotopic exchange between these fluids.     

Fractionation of Oxygen and Hydrogen Isotopes at the Hydrate Gas forming in the Sea Sediments

The paper gives data on isotope composition of interstitial and near-bottom waters sampled in a region of gas-hydrate formation in the Sea of Okhotsk. The studies shows that heavy isotope of oxygen and hydrogen is used in gas-hydrate formation, with the result that isotope composition of its constitution water constitutes δ¹⁸O = +1.99‰, δD = +23‰ relatively to SMOW. Formation of autogenic carbonates leads to isotope exchange with interstitial water wich, in turn, changes its primary isotope composition in the direction of increasing of O-18 content. The near-bottom waters are isotope-light relatively to the SMOW standard and to the mean isotope composition of interstitial water in the studied region of gas-hydrate spreading.