ICP-MS和ICP-AES测定地球化学勘查样品及稀土矿石中铌钽方法体系的建立   总被引：6，自引：4，他引：2  

高会艳 《岩矿测试》2014,33(3):312-320

针对目前铌钽分析中出现的样品溶解不完全、元素易水解及现有分析技术流程复杂的情况,本文对常用的混合酸恒温电热板溶解和过氧化钠碱熔两种样品前处理方式进行优化,运用电感耦合等离子体质谱法(ICP-MS)、电感耦合等离子体发射光谱法(ICP-AES)两种技术手段,建立了测定地球化学勘查样品及稀土矿石中不同含量水平的铌、钽两套分析方法。对于铌、钽含量较低且易于分解的样品,采用硝酸-氢氟酸-硫酸混合酸恒温电热板消解ICP-MS方法测定;对于铌、钽含量高且难溶的样品,采用过氧化钠高温熔融ICP-AES方法测定。ICP-MS用于分析低含量样品更具优势,而高含量样品更适合运用ICP-AES。通过分析土壤、水系沉积物、岩石、稀有稀土矿石系列国家标准物质,结果表明混合酸处理ICP-MS分析方法的线性范围为0~200ng/mL;检出限为铌0.01μg/g,钽0.05μg/g;相对误差小于10%,精密度(RSD)小于6%;碱熔处理ICP-AES分析方法的线性范围为0~30μg/mL,检出限为铌0.2μg/g,钽2.5μg/g,相对误差小于10%,精密度(RSD)小于7%。这两套分析方法可以满足基体复杂、铌钽含量变化范围大、试样批量大的检测要求。  相似文献   

电感耦合等离子体发射光谱法测定地球化学样品中的钍   总被引：1，自引：1，他引：0  

汪君  王頔  邓长生  张建梅  羊鸫  王斌堂  朱素霞 《岩矿测试》2014,33(4):501-505

运用电感耦合等离子体发射光谱(ICP-AES)测定地球化学样品中的钍,样品处理方法通常是采用四酸溶矿。但在实际测定中发现,当钍含量接近本底时,检测结果不稳定;当基体干扰大时,钍含量甚至无法检出。本文对样品前处理方法进行改进,采用过氧化钠碱熔样品,10 g/L氢氧化钠溶液过滤洗涤,再用热的40%盐酸溶解沉淀,ICP-AES法测定钍的含量。通过实验确定了钍的最佳分析谱线为401.913 nm,方法检出限为0.21μg/g,精密度(RSD,n=6)为7.7%~15.9%,准确度(n=6)为7.0%~10.0%,加标回收率为92.0%~104.0%。经国家标准物质验证,本方法可准确测定钍含量大于0.21μg/g的样品。方法简便快捷,干扰少,较一般的酸溶ICP-AES测定方法的检出限(0.6~0.7μg/g)低,适用于大批量实际样品的快速检测。  相似文献   

石英岩化学成分分析标准物质研制   总被引：4，自引：4，他引：0  

刘瑱  马玲  时晓露  查立新 《岩矿测试》2014,33(6):849-856

目前巴西、英国、日本、南非等国研制有一些石英岩类标准物质,SiO₂含量均在96%以上,含量范围较窄,定值元素较少。我国尚无石英岩类的标准物质,无法满足石英岩勘查和实际应用的需要。本文研制了3个石英岩化学成分分析标准物质,样品采自我国具有代表性的安徽省凤阳县大庙镇老青山、青海省大通县景阳镇和湖北省蕲春县灵虬山三个石英矿区,利用流化床式气流粉碎机将样品细碎至-45 μm,解决了纯度较高的石英岩粉碎加工易受污染的难题。因石英岩样品难以压制成型,均匀性检验未采用压片制样X射线荧光光谱法,而是采用以电感耦合等离子体发射光谱法和电感耦合等离子体质谱法为主的检验方法。结果表明,方差检验的F值均小于临界值,证明其均匀性符合要求。为期两年的长期稳定性8次检验中未发现统计学意义上的明显变化,在颠震和极端温度条件下所检验的短期稳定性良好。经我国十家实验室使用多种分析方法联合定值,同时探索采用类似元素比较法获取未进行均匀性和稳定性检验的成分的相应不确定度分量,给出了36个成分的认定值(或参考值)和相应的不确定度。3个标准物质现已被批准为国家一级标准物质(编号GBW 07835、GBW 07836、GBW 07837),其主要成分SiO₂的含量相应为92.93%、95.97%、99.18%,呈梯度分布。此系列标准物质具有样品粒度均匀、粒度分布范围窄(D₂₅～D₇₅在4～16 μm之间),定值元素种类多,SiO₂含量分布广泛的特点,可以满足石英岩样品化学成分分析过程中监控的需要。  相似文献   

水泥生产碳排放的产生环节及减排措施     

逄思宇  曹烨 《化工矿产地质》2014,(4):250-254

在工业生产过程中,CO2的大量排放被认为是导致气候变暖的重要因素之一,因此控制和减少CO2排放已成为人类社会面临的紧迫任务。水泥工业是人为排放CO2的重要来源之一,这就意味着水泥工业会在一种不断增加的管理压力下减少CO2的排放量,以应对全球变暖的现状。水泥生产过程中CO2的直接排放和间接排放两大排放途径,直接排放主要包括碳酸盐分解,烧成燃料/非烧成燃料的燃烧。间接排放主要是指电力消耗所产生的CO2。针对碳的排放环节,有效可行的CO2减排措施,例如原料、燃料的替代,熟料化学成分的改变,能源效率的提高等,对我国水泥工业的碳减排提出一些建议和看法。  相似文献   

Point and Diffuse Nutrient Emissions and Transports in the Odra Basin and its Main Tributaries     

H. Behrendt  M. Kornmilch  R. Korol  M. Stronska  W.-G. Pagenkopf 《洁净——土壤、空气、水》1999,27(5):274-281

The river Odra is one of the biggest transboundary rivers in Central Europe. The basin is characterized by an area of 110 074 km?sk (upstream Krajnik Dolny) and a population of about 15.5 million inhabitants. Compared with the Westeuropean river basins the specific runoff of the Odra basin is low and amounts only 4.5 L km?sk s–1. The long term changes of the average annual nutrient transport of the Odra at Krajnik Dolny show for the period 1991 to 1994 a low reduction for phosphorus but no changes for nitrogen. For the period of 1991 to 1994 an inventory of the point sources produces emissions of 10.7 kt a–1 P and 54.4 kt a–1 N upstream of the station Krajnik Dolny/Schwedt. Emissions from agricultural land and urban areas represent the main diffuse sources. A range of 68 to 96 kt a–1 N and 3.3 to 3.9 kt a–1 P were estimated for the total diffuse emissions depending on the database and the method of modeling. The emission situation of the river is characterized by a high dominance of point sources in the case of phosphorus (about 73%). For nitrogen the diffuse emissions dominate the total emissions to an amount between 59 and 67%. Compared to the emissions the nutrient transport is low. An average load of 5.1 kt a–1 P and 70.1 kt a–1 N was observed at the station Krajnik Dolny for the period 1991 to 1994. The emission and load situation within the main tributaries of the river Odra is comparable to the whole basin. The big difference between the total emissions and the observed load refers to intensive retention and loss processes within the river system of the Odra.  相似文献   

The global scale,distribution and growth of aviation: Implications for climate change     

《Global Environmental Change》2020

Prior to the COVID-19 crisis, global air transport demand was expected to triple between 2020 and 2050. The pandemic, which reduced global air travel significantly, provides an opportunity to discuss the scale, distribution and growth of aviation until 2018, also with a view to consider the climate change implications of a return to volume growth. Industry statistics, data provided by supranational organizations, and national surveys are evaluated to develop a pre-pandemic understanding of air transport demand at global, regional, national and individual scales. Results suggest that the share of the world’s population travelling by air in 2018 was 11%, with at most 4% taking international flights. Data also supports that a minor share of air travelers is responsible for a large share of warming: The percentile of the most frequent fliers – at most 1% of the world population - likely accounts for more than half of the total emissions from passenger air travel. Individual users of private aircraft can contribute to emissions of up to 7,500 t CO₂ per year. Findings are specifically relevant with regard to the insight that a large share of global aviation emissions is not covered by policy agreements.  相似文献   

Characterization of dissolved organic matter fluorescence in the South Atlantic Bight with use of PARAFAC model: Interannual variability   总被引：13，自引：0，他引：13  

Piotr Kowalczuk  Michael J. Durako  Heather Young  Amanda E. Kahn  William J. Cooper  Michael Gonsior 《Marine Chemistry》2009,113(3-4):182-196

Systematic water sampling for characterization of chromophoric dissolved organic matter (CDOM) in the coastal South Atlantic Bight, was conducted as part of the long term Coastal Ocean Research and Monitoring Program (CORMP). Water samples were collected during a 3.5 year period, from October 2001 until March 2005, in the vicinity of the Cape Fear River (CFR) outlet and in adjacent Onslow Bay (OB). During this study there were two divergent hydrological and meteorological conditions in the CFR drainage area: a severe drought in 2002, followed by the very wet year of 2003. CDOM was characterized optically by the absorption coefficient at 350 nm, the spectral slope coefficient (S), and by Excitation Emission Matrix (EEM) fluorescence. Parallel Factor Analysis (PARAFAC) was used to assess CDOM composition from EEM spectra and six components were identified: three terrestrial humic-like components, one marine humic-like component and two protein-like components. Terrestrial humic-like components contributed most to dissolved organic matter (DOM) fluorescence in the low salinity plume of the CFR. The contribution of terrestrial humic-like components to DOM fluorescence in OB was much smaller than in the CFR plume area. Protein-like components contributed significantly to DOM fluorescence in the coastal ocean of OB and they dominated DOM fluorescence in the Gulf Stream waters. Hydrological conditions during the observation period significantly impacted both concentration and composition of CDOM found in the estuary and coastal ocean. In the CFR plume, there was an order of magnitude difference in CDOM absorption and fluorescence intensity between samples collected during the drought compared to the wet period. During the drought, CDOM in the CFR plume was composed of equal proportions of terrestrial humic-like components (ca. 60% of the total fluorescence intensity) with a significant contribution of proteinaceous substances (ca. 20% of the total fluorescence). During high river flow, CDOM was composed mostly of humic substances (nearly 75% of total fluorescence) with minor contributions by proteinaceous substances. The impact of changes in fresh water discharge patterns on CDOM concentration and composition was also observed in OB, though to a lesser degree.  相似文献   

IPCC emission scenarios: How did critiques affect their quality and relevance 1990–2022?     

《Global Environmental Change》2022

Long-term global emission scenarios enable the analysis of future climate change, impacts, and response strategies by providing insight into possible future developments and linking these different climate research elements. Such scenarios play a crucial role in the climate change literature informing the Intergovernmental Panel on Climate Change’s (IPCC) Assessment Reports (ARs) and support policymakers. This article reviews the evolution of emission scenarios, since 1990, by focusing on scenario critiques and responses as published in the literature. We focus on the issues raised in the critiques and the possible impact on scenario development. The critique (280) focuses on four areas: 1) key scenario assumptions (40%), 2) the emissions range covered by the scenarios and missing scenarios (25%), 3) methodological issues (24%), and 4) the policy relevance and handling of uncertainty (11%). Scenario critiques have become increasingly influential since 2000. Some areas of critique have decreased or become less prominent (probability, development process, convergence assumptions, and economic metrics). Other areas have become more dominant over time (e.g., policy relevance & implications of scenarios, transparency, Negative Emissions Technologies (NETs) assumptions, missing scenarios). Several changes have been made in developing scenarios and their content that respond to the critique.  相似文献   

Thermodynamical analysis of acoustic Schwarzschild black hole     

《New Astronomy》2024

In this paper, we analyze the thermodynamic properties of acoustic Schwarzschild black holes with its parameter. The study is conducted in the extended phase space displaying the phase transition. This phase transition is examined through Gibbs free energy, specific heat, and heat capacity. Later, we discuss the thermal stability of acoustic black holes through Hawking temperature by identifying their stable and unstable regions. We calculate the corrected entropy to examine the thermal fluctuations. Through the corrected entropy we observe that there is no fluctuation in the case of small black holes. We also discuss the energy emission process from acoustic black holes. Moreover, we employ the generalized uncertainty principle to obtain a modified Lagrangian equation. We analyze the tunneling and Hawking temperature of the acoustic Schwarzschild black hole after solving the field equations.  相似文献