原子荧光光谱仪在黄金矿山金测定中的应用

本文着重介绍了原子荧光光谱仪在黄金矿山中的应用。该仪器与化学法和其它类型的仪器相比较,具有灵敏度高（DL：〈1×10-9）、重现性好（RSD：〈2.0%）、分析速度快等优点。同时简单介绍了目前测定金的一些其它方法,包括原子吸收和发射光谱、化学分析等方法在应用过程中的优缺点和所遇到的情况,论证了原子荧光光谱仪在黄金矿山金...     

氢化物发生-原子荧光光谱法直接测定地球化学样品中痕量碲

采用硝酸-氢氟酸-高氯酸溶解样品,以Fe3 作减缓剂,不需分离富集,用氢化物发生-原子荧光光谱法直接测定地球化学样品中痕量碲.对测定介质、KBH4浓度、铁盐的作用等条件进行试验.方法检出限为0.0031μg/g,精密度(RSD,n=11)＜6.10%.方法用于国家一级地球化学标准物质中痕量碲的测定,结果与标准值一致.     

大兴安岭地区浅覆盖层对地面伽马能谱测量的影响

讨论在大兴安岭地区进行地质填图中浅覆盖层对伽马能谱测量的影响问题。通过放射性元素的取样分析、岩石—土壤的矿物分析以及实测剖面分析,得知了伽马能谱测量的影响因素,从而为应用伽马能谱测量解决地质填图中的问题提供了依据。     

石墨炉原子吸收分光光度法测定土壤样品中痕量镉

研究了土壤样品中痕量镉的石墨炉原子吸收分光光度法测定最佳条件以及磷酸二氢铵与硝酸镁作基体改进剂对测定镉的基体改进效应，并比较了两种试样分解体系。方法检出限为0.01pg／L，精密度(RSD，n=8)为3．29％-7．69％，经国家一级标准物质分析验证，结果与标准值符合。     

静电场轨道阱质谱在水中溶解性有机质表征中的应用进展

溶解性有机质(Dissolved Organic Matter,DOM)在水生生态环境中广泛存在,影响着水环境中多种物质的生物地球化学性质.分析其组成与含量具有重要的生态环境意义,是生态环境科学领域研究的热点.溶解性有机质组成非常复杂,其分子组成的解析一直是难题.近年来,具有高分辨率、高灵敏度、高通量、高扫描速率等特性...     

高压下天然菱铁矿的压缩性和电子结构研究

采用同步辐射光源和金刚石对顶砧(DAC)技术,对天然菱铁矿的压缩性和电子结构进行了原位X射线衍射(XRD)和X射线吸收近边结构谱(XANES)测试研究。在室温下随着压力逐渐升高至50.2 GPa,菱铁矿保持方解石型结构不变,但是逐渐向Na Cl型结构转变;刚性[CO3]2-基团平行于ab-平面定向排列使c轴的压缩性大于a轴。菱铁矿在44.6~47.1 GPa之间发生电子由高自旋态(HS)向低自旋态(LS)的转变,表现为体积塌陷8%。HS菱铁矿的等温状态方程参数为K0=112(5)GPa和K'0=4.6(3)。首次采用XANES技术对菱铁矿中Fe2+的电子结构进行了研究,结果表明:随着压力升高至37.3 GPa,Fe2+的配位和局域对称并未发生明显变化;此后电子结构开始转变,Fe2+的3d轨道分裂能降低,电子跃迁概率增大,呈现LS特性。     

Seasonal dynamics of light absorption by chromophoric dissolved organic matter (CDOM) in the NW Mediterranean Sea (BOUSSOLE site)

We analyze a two-year time-series of chromophoric dissolved organic matter (CDOM) light absorption measurements in the upper 400 m of the water column at the BOUSSOLE site in the NW Mediterranean Sea. The seasonal dynamics of the CDOM light absorption coefficients at 440 nm (a_cdom(440)) is essentially characterized by (i) subsurface maxima forming in spring and progressively reinforcing throughout summer, (ii) impoverishment in the surface layer throughout summer and (iii) vertical homogeneity in winter. Seasonal variations of the spectral dependence of CDOM absorption, as described by the exponential slope value (S_cdom), are characterized by highest values in summer and autumn at the surface and low values at the depths of a_cdom(440) subsurface maxima or just below them. Variations of a_cdom(440) are likely controlled by microbial digestion of phytoplankton cells, which leads to CDOM production, and by photochemical destruction (photobleaching), which leads to CDOM degradation. Photobleaching is also the main driver of S_cdom variations. Consistently with previous observations, a_cdom(440) for a given chlorophyll a concentration is higher than expected from Case I waters bio-optical models. The total non-water light absorption budget shows that surface waters at the BOUSSOLE site are largely dominated by CDOM during all seasons but the algal bloom in March and April. These results improve the knowledge of CDOM absorption dynamics in the Mediterranean Sea, which is scarcely documented. In addition, they open the way to improved algorithms for the retrieval of CDOM absorption from field or satellite radiometric measurements.     

The potential of historic rock avalanches and man-made structures as chlorine-36 production rate calibration sites

Samples from three medieval rock avalanches from the French (Le Claps, Mont Granier) and Austrian Alps (Dobratsch) and a man-made structure, i.e. the Stephansdom in Vienna, have been analysed for in-situ produced ³⁶Cl by accelerator mass spectrometry (AMS). All four sampling sites of independently known exposure duration turned out to be not appropriate as calibration sites for the determination of the ³⁶Cl-production rate from Ca. Indeed, the determination of short exposure ages for dating rock avalanches and man-made structures by ³⁶Cl is hindered dramatically by inheritance, especially for samples characterized by high ^natCl-concentrations. Generally, there are hints that the theoretical calculation of ³⁶Cl-production from epithermal and thermal neutron-capture on ³⁵Cl is highly underestimated in all existing models, thus, asking for particular precaution if working on high-Cl samples for any project. Hence, this work evidences that potential high inheritance, even for samples reasonably shielded before exhumation, has to be considered especially when dealing with recently exposed surfaces such as glacially polished rocks, alluvial terraces, fault scarps etc.     

Speciation and Determination of Inorganic Mercury and Methylmercury by Headspace Single Drop Microextraction and Electrothermal Atomic Absorption Spectrometry in Water and Fish

In this study, headspace single drop microextraction (HS‐SDME) method in combination with electrothermal atomic absorption spectrometry (ETAAS) method was developed and validated for the speciation and determination of inorganic mercury (iHg) and methylmercury (MeHg). MeHg and iHg species were reduced to volatile methylmercury hydride (CH₃HgH) and elemental mercury, respectively, in the presence of NaBH₄ and trapped onto a drop of acceptor phase in the tip of a microsyringe. Thiourea and ammonium pyrrolydinedithiocarbamate (APDC) were tested as the acceptor phase. The experimental parameters of the method such as microextraction time, temperature, NaBH₄ concentration, acceptor phase concentration, and pH of the medium were investigated to obtain distinctive conditions for mercury species. Possible interference effects have also been investigated. In order to validation of the method, analytical figures of merits such as accuracy, precision, limit of detection (LOD), limit of quantitation (LOQ), and linear working range have been evaluated. Accuracy of the method has been verified by analyzing certified reference materials (BCR 453 Tuna fish) and spiked samples. The proposed method was applied for the speciation and determination of mercury species in water and fish samples. Mercury species (MeHg and iHg) have been determined in the real samples with a relative error less than 10%.     

大型岩体洞室采用柔性垫层减震的可行性研究

采用无限元作为岩体地下洞室静动力分析的边界条件,建立了岩体地下洞室的静动力有限元一无限元(FE-IE)计算模型,分析了柔性垫层对水电站厂房这类大型岩体洞室结构的减震效果.研究结果表明:柔性垫层虽未能从根本上改变岩体洞室结构的地震响应,但是设置一定厚度的柔性垫层后不仅能充分发挥岩体洞室围岩的自承能力,而且还能明显地减小混...