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D Banks AK Midtg?rd B Frengstad JR Krog T Strand 《Canadian Metallurgical Quarterly》1998,222(1-2):93-105
Seventy-two samples of groundwater derived from Norwegian Quaternary (largely glaciofluvial or glacial) aquifers were analysed for a wide range of major and minor hydrochemical parameters. The waters exhibit a relatively uncomplex evolution from Na-Cl dominated, immature waters (which reflect marine salts in precipitation) to Ca-HCO3 dominated waters via calcite dissolution. The median pH of these waters is 7.37, in contrast to similar waters from crystalline bedrock aquifers with a median pH of 8.07. The water samples provide little evidence of significant acidification or sulphatisation of groundwaters by 'acid rain'. In fact, a positive correlation emerges between non-marine sulphate and alkalinity/pH, suggesting dominantly lithological sources for non-marine sulphate. No groundwaters from Quaternary deposits exceed maximum recommended concentrations for Rn, F- and Na, while 10% fall outside the required pH range. This again contrasts with bedrock aquifers where 30% of waters are non-compliant with respect to one or more of these parameters. 相似文献
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以标准物质作为参照物,采用熔融法制样,建立了测定镁砂及其矿物原料(镁石、菱镁矿)中SiO2、Al2O3、CaO、MgO、Fe2O3、MnO、P2O5、TiO2含量的X射线荧光光谱法。讨论了熔融制样采用的熔剂体系、样品与熔剂的稀释比例、融熔制样的温度和时间对制样精度及测量准确度的影响。探讨了镁石、菱镁矿等碳酸盐样品烧损量对测定结果的影响和校正方法。本方法应用于镁砂、镁石、菱镁矿标准样品及镁砂实际样品的分析,测定值与认定值或其他方法的测定值相一致,所得分析结果能够满足镁砂中常见组分快速分析的需要。 相似文献
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采用玻璃熔片法制样,建立测定铁矿石中TFe、SiO2、Al2O3、CaO、MgO、MnO、K2O、Ti O2、P、S等主次成分的X射线荧光光谱分析方法。确定了仪器最佳参数,采用系列标样建立了校准曲线,以数学法校正基体效应。对稀释比、熔样时间等进行了探讨,结果表明,试样和熔剂的质量比以1∶15、熔样时间以15 min为好,所得试样在熔剂中的分散度(浓度)适当,可同时适合试样中高、低含量组分的测定。采用熔融法分解试样的方法有效地消除了试样的粒度效应,精确度试验表明,待测元素的相对标准偏差在0.10%~7.14%之间,能满足铁矿石中各元素的检测要求。 相似文献
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采用熔融片法制样,使用X射线荧光光谱仪测定了铜矿中的13种主次量元素。为了有效地控制在熔样过程中硫的挥发,重点讨论了熔融制片法熔剂、氧化剂、脱模剂的选择及用量,预氧化及熔融温度和时间的选择。对分析元素谱线选择、基体效应和谱线重叠干扰校正等也作了详细讨论。实验表明,熔片制备过程中加入氧化剂硝酸锶既可使坩埚避免被腐蚀,又可准确测定铜精矿中的S,氧化效果最佳。此外,采用Sr作为测量铜元素的内标,分析结果的准确度和精密度均得到很好改善。X射线荧光光谱熔片法测定铜矿中的主次元素结果与参考值一致,表明该法能够有效应用于铜矿中主次元素的测量。 相似文献
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S. M. L. Sastry P. J. Meschter J. E. O’neal 《Metallurgical and Materials Transactions A》1984,15(7):1451-1463
The feasibility of developing dispersion-strengthened powder metallurgy Ti alloys was determined in Ti-RE (RE = Ce, Dy, Er, Gd, La, Nd, or Y) alloys prepared by rapid solidification processing. The alloys were produced by electron-beam melting and splat quenching. Dispersoid precipitation and growth were studied as functions of annealing temperature, 700 to 1000 °C, for annealing times between 5 and 50,000 minutes. Dispersoid diameters, spacings, compositions, and crystal structures were characterized by transmission and scanning electron microscopy, X-ray and electron diffraction, energy-dispersive X-ray analysis, and scanning Auger microscopy. Two classes of dispersoid coarsening behavior at temperatures below theβ-transus were identified. In Ti-Ce, Ti-Gd, and Ti-Nd alloys, equilibrium rare earth sesquioxide (RE2O3) dispersoids form early in the annealing process and coarsen rapidly to > 1 μm diameter. The Ti-Nd alloys additionally contain large volume fractions of small (< 100 nm diameter) dispersoids. In the other Ti-RE alloys, dispersoids identified as Ti-RE-O-C compounds coarsen relatively slowly. Ti-Er is the most promising of the investigated systems for application in a multicomponent dispersion-strengthened alloy because long-time annealing at 700 to 800 °C produces stable dispersoids of 50 to 150 nm average diameter and 300 to 600 nm inter-particle spacing. 相似文献
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ICP-AES/AFS联合测定金矿地质样品中32种主次痕量元素 总被引:1,自引:0,他引:1
建立了电感耦合等离子体发射光谱(ICP-AES)与原子荧光光谱(AFS)联合测定金矿地质样品中32种主、次、微痕量元素的方法。样品分别采用HNO3-HF-HCl O4-H3PO4和KOH及含酒石酸的王水分解,ICP-AES依次测定主量元素Si、Al、Ca、Mg、Fe、P,较高含量元素Mo、Sn、W,以及Ag、As、B、Ba、Be、Bi、Ce、Co、Cr、Cu、K、Mn、Na、Sb、Sr、Ti、Ni、Pb、V、Zn等;AFS依次测定微痕量Hg和Se、Te。该方法应用于金矿地质样品和多金属国家标准样品分析,测定结果与推荐值吻合,精密度(RSD)小于10%,为金矿地质样品化学组成和多金属矿床成矿环境、成因机制的研究以及矿产资源的综合利用等,提供了充分的依据。 相似文献
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报道了一种快速测定多金属矿中Al、Ca、Mg、Mn、Fe、Ti、Cu、Ag、Pb、Zn、As、Mo、Cd等13种元素的电感耦合等离子体原子发射光谱(ICP-AES)法。样品经混合酸(HCl和HNO3)缓慢溶解和氢氟酸除硅后,在HNO3介质中,用ICP-AES法测定其中的主次量元素。讨论了溶样条件和基体效应等影响因素。为了消除基体效应和待测元素间的谱线干扰,通过配制与样品中组分相同的校准溶液绘制校准曲线和选取干扰小的谱线作为待测元素分析线。实验结果表明,在上述条件下进行测定,各元素之间没有干扰,标准样品测定值与认定值一致,测定结果的相对标准偏差(RSD,n=12)在0.83%~3.4%之间。与现行的单元素分析方法相比,分析周期短,适用于多金属矿日常检验。 相似文献
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Bylsma Lauren M.; Taylor-Clift April; Rottenberg Jonathan 《Canadian Metallurgical Quarterly》2011,120(1):155
Although emotional dysfunction is an important aspect of major depressive disorder (MDD), it has rarely been studied in daily life. Peeters, Nicolson, Berkhof, Delespaul, and deVries (2003) observed a surprising mood-brightening effect when individuals with MDD reported greater reactivity to positive events. To better understand this phenomenon, we conducted a multimethod assessment of emotional reactivity to daily life events, obtaining detailed reports of appraisals and event characteristics using the experience-sampling method and the Day Reconstruction Method (Kahneman, Krueger, Schkade, Schwarz, & Stone, 2004) in 35 individuals currently experiencing a major depressive episode, 26 in a minor depressive (mD) episode, and 38 never-depressed healthy controls. Relative to healthy controls, both mood-disordered groups reported greater daily negative affect and lower positive affect and reported events as less pleasant, more unpleasant, and more stressful. Importantly, MDD and mD individuals reported greater reductions in negative affect following positive events, an effect that converged across assessment methods and was not explained by differences in prevailing affect, event appraisals, or medications. Implications of this curious mood-brightening effect are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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采用四硼酸锂挂壁制备熔剂坩埚,分散剂溶解并分散硅铁合金样品,蒸干过量水分后加混合熔剂[m(Li2B4O7)∶m(LiBO2)=67∶33]熔融制样,用X射线荧光光谱仪对硅铁合金中Si、Fe、Mn、Al、Ca等元素同时进行测定。本法有效避免了硅铁合金熔融过程中铂金坩埚腐蚀问题,且能够制得适合荧光分析硅铁合金玻璃片,实现了快速而准确地分析硅铁合金中主元素和微量元素。采用本方法分析硅铁合金标准样品,测定值与认定值相符,且主次元素相对标准偏差均能满足硅铁合金测定需要。 相似文献
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采用X射线荧光光谱法(XRF)测定稀土硅铁中硅、锰、铝、铁、钛及镧系元素时,熔融制样过程中氧化条件不好控制,容易造成挂壁坩埚过早熔化或坩埚挂壁不好的现象,使铂-金坩埚受到严重侵蚀。实验以四硼酸锂为熔剂铺底保护铂-金坩埚,使用碳酸锂对稀土硅铁样品进行烧结氧化;再采用过氧化钠进行深度氧化,解决了稀土硅铁合金对铂-金坩埚腐蚀的问题。试样和四硼酸锂熔剂的质量比为1∶30,在1 100℃下熔融试样12 min,可制得表面质量良好的玻璃片,有效地消除了试样的粒度效应和矿物效应影响。按照实验方法测定稀土硅铁中硅、锰、铝、钙、铁、钛、镧、铈、镨、钕、钐等11种主次元素,结果的相对标准偏差(RSD,n=10)为0.39%~5.0%,与标准方法及滴定法分析结果吻合较好,能满足稀土硅铁中主次元素的检测需求。 相似文献
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铬铁矿是一种极难分解的矿物,包含多种元素,常见的分析方法是将每种元素单独取样分析,费时费力,因此有必要寻求一种简便快速的分析方法。采用1.5g碳酸钠-四硼酸钠在1000℃熔融30min分解样品,选用50mL 25%(V/V)盐酸进行酸化处理,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定铬、铁、铝、镁、硅、钙、钛、锰、钴、镍、钒等元素含量,建立了电感耦合等离子体原子发射光谱法测定铬铁矿中主次量元素铬、铁、铝、镁、硅、钙、钛、锰、钴、镍、钒等的方法。考察了铬对其他元素的影响,用加铬和不加铬的标准溶液系列测定其他元素,结果无明显差别,因此选用不加铬的标准溶液系列测定其他元素。在线性范围内,各元素校准曲线的线性相关系数均不小于0.9995;方法检出限为0.0003%~0.008%。按照实验方法测定铬铁矿标准物质GBW07201和GBW07819中铬、铁、铝、镁、硅、钙、钛、锰、钴、镍、钒,结果的相对标准偏差(RSD,n=12)为0.41%~5.5%,测定值和认定值一致。 相似文献
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采用氢氧化钾在700℃熔融20min,经盐酸酸化、稀释10倍后,选取Si 251.611nm、Al 396.153nm、Ca 317.933nm、Mg 285.213nm、Ba 233.527nm、P 334.940nm、Cu 213.617nm、Fe 327.393nm、Sr 407.771nm为分析线,使用电感耦合等离子体原子发射光谱法(ICPAES)同时测定Si、Al、Ca、Mg、Ba、P、Cu、Fe、Sr,从而建立了炼钢用脱氧剂中9种主、次量元素的测定方法。结果表明,与酸溶方式相比,采用碱熔前处理对常见的各类脱氧剂可以避免分解不彻底的问题。当称样量为0.1g时,加入2.0g氢氧化钾熔剂可以使样品熔解完全。采用基体匹配法绘制校准曲线可以有效消除基体效应的影响,各元素质量浓度在一定范围内与其发射强度呈线性,校准曲线的线性相关系数r≥0.999 8,各元素的检出限在0.001 6%~0.012%之间。按照实验方法测定脱氧剂样品中Si、Al、Ca、Mg、Ba、P、Cu、Fe、Sr,结果的相对标准偏差(RSD,n=11)在0.81%~4.5%之间。实验方法用于测定4个脱氧剂标准样品(E511d、YSB 14609-2001、YSB 14606-2001、YSB 14607-2001)中Si、Al、Ca、Mg、Ba、P、Cu、Fe、Sr,测定值与认定值吻合较好,相对误差在0.25%~7.14%之间。 相似文献
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准确测定钛铁矿中主次元素对提高钛铁矿的选钛技术及有益元素的综合回收具有指导意义。钛铁矿难溶易水解,一般很难实现一次分解多元素同时测定。采用3 mL HF-1 mL HNO3-0.5 mL H2SO4于180 ℃高压密闭消解10 h,用5 mL逆王水180 ℃高压密闭方式溶解盐类5 h,在线引入Rh、Re混合内标,采用标准模式测定Li、Be、Sc、Ti、V、Cr、Mn、Co、Ni、Cu、Zn、Ga、Rb、Sr、Y、Mo、Cd、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu、W、Pb、U,动能歧视模式测定Fe、Zr、Nb、La、Ce、Hf、Ta,对于受质谱干扰严重的V、Ni、Cd、Eu、Gd、Tb,通过数学校正方程在线进行校正,建立了电感耦合等离子体质谱法(ICP-MS)测定钛铁矿中39种主次元素的方法。方法校准曲线的相关系数均不小于0.999 6,检出限为0.002~2.4 μg/g,将其应用于钛铁矿成分分析标准物质分析,结果的相对误差(RE)为-10.0%~13.0%,相对标准偏差(RSD,n=12)均不大于3.5%;对主量元素及缺少认定值的元素进行加标回收试验,回收率为96%~104%。采用实验方法对钛铁矿样品进行分析,测得结果的相对标准偏差(RSD,n=12)均不大于4.1%。 相似文献
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The mathematical model described in Part I[14] was extended to include the minor element behavior inside a flash-furnace shaft during flash smelting of copper concentrate.
The volatilization of As, Sb, Bi, and Pb was computed, and experiments were carried out for Sb and Pb in a laboratory flash
furnace. Satisfactory agreement between the predicted and measured results was obtained for antimony and lead. From the computational
results, the behavior of each minor element was predicted for various target matte grades. The model predictions show that
the elimination of As and Bi to the gas phase increases sharply at about 0.3 m from the burner; however, that of the Sb increases
gradually along the flash-furnace shaft, and that of lead occurs suddenly at about 0.6 m from the burner. The predicted results
also show that the elimination increases for Bi and Pb as the target matte grade increases; however, it is relatively independent
of the target matte grade between 50 and 60 pet Cu for As and Sb. At higher target matte grades above 60 pet Cu, the elimination
of As and Sb decreases as matte grade increases.
formerly Graduate Student, Department of Chemical Engineering, University of Utah, 相似文献
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TR Mahalingam S Vijayalakshmi RK Prabhu A Thiruvengadasami CK Mathews KR Shanmugasundaram 《Canadian Metallurgical Quarterly》1997,57(3):191-206
Blood is one of the widely used specimens for biological trace element research because of its biological significance and ease of sampling. We have conducted a study of the blood of the Kalpakkam township population for trace and minor elements. For this purpose, analytical methods have been developed and standardized in our laboratory for the elemental analysis of blood plasma and red cells. Inductively coupled plasma-mass spectrometry (ICP-MS), a relatively new technique, has been applied for the analysis of trace elements. Details regarding spectral interference and matrix interference encountered in the analysis of blood and the methods of correcting them have been discussed. Flame atomic absorption spectrometry (AAS)/atomic emission spectrometry (AES) has been applied for the determination of minor elements. Precision and accuracy of these methods have also been discussed. 相似文献
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AT Beekman DJ Deeg AW Braam JH Smit W Van Tilburg 《Canadian Metallurgical Quarterly》1997,27(6):1397-1409
BACKGROUND: The consequences of major depression for disability, impaired well-being and service utilization have been studied primarily in younger adults. In all age groups the consequences of minor depression are virtually unknown. In later life, the increased co-morbidity with physical illness may modify the consequences of depression, warranting special study of the elderly. With rising numbers of elderly people, excess service utilization by depressed elderly represents an increasingly important issue. METHODS: Based on a large, random community-based sample of older inhabitants of the Netherlands (55-85 years), the associations of major and minor depression with various indicators of disability, well-being and service utilization were assessed, controlling for potential confounding factors. Depression was diagnosed using a two-stage screening design. Diagnosis took place in all subjects with high depressive symptom levels and a random sample of those with low depressive symptom levels. The study sample consists of all participants to diagnostic interviews (N = 646). RESULTS: As in younger adults, associations of both major and minor depression with disability and well-being remained significant after controlling for chronic disease and functional limitations. Adequate treatment is often not administered, even in subjects with major depression. As the vast majority of those depressed were recently seen by their general practitioners, treatment could have been provided in most cases. Bivariate analyses show that major and minor depression are associated with an excess use of non-mental health services, underscoring the importance of recognition. In multivariate analyses the evidence of excess service utilization was less compelling. CONCLUSIONS: Both major and minor depression are consequential for well-being and disability, supporting efforts to improve the recognition and treatment in primary care. However, controlled trials are necessary to assess the impact this may have on service utilization. 相似文献
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Pettit Jeremy W.; Lewinsohn Peter M.; Seeley John R.; Roberts Robert E.; Yaroslavsky Ilya 《Canadian Metallurgical Quarterly》2010,119(4):811
Stress generation and stress exposure models of the relations among depressive symptoms, minor hassles, and major event stress were investigated among 815 community-dwelling participants. Autoregressive latent trajectory models were constructed to examine latent growth patterns from ages 15 years to 30 years and to test 1-year lagged, reciprocal paths between depressive symptoms and stress constructs. Results indicated significant cross-sectional and longitudinal associations between depressive symptoms and both stress constructs at the latent level. At the manifest level, lagged paths from hassles at 1 year to depressive symptoms at the next year were significant between ages 17 years and 24 years. Significant cross-sectional paths between major events and depressive symptoms were found between ages 24 years and 28 years, and modest support was found for lagged paths from depressive symptoms to major events 1 year later. Findings generally suggest a high degree of covariation in depressive symptoms and stress concurrently and over time. One-year lagged predictive effects net of the associations between individuals' latent trajectories appear to be weak, constrained to specific time periods, and most consistent with a stress exposure effect of hassles on depressive symptoms. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献