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21.
多金属结核中二氧化锰的测定 总被引:1,自引:0,他引:1
用过量的含有H2SO4的(NH4)2Fe(SO4)2溶液分解多金属结核的同时,还原了试样中的MnO2,然后以K2Cr2O7标准溶液滴定测定了多金属结核中的MnO2。就样品分解过程中的加热温度和时间对测定结果的影响及标准溶液的标定等问题进行了讨论,经多次测定,方法重现性好。应用此方法为新研制的多金属结核标准物质提供了MnO2的定值数据,其结果与初定值相符,无剔除值,精密度(RSD,n=8)小于06%。 相似文献
22.
光度法测定痕量钛的研究 总被引:6,自引:1,他引:6
基于痕量Ti(Ⅳ)在稀H2SO4介质中对EDTA还原Cr2O2-7褪色反应的抑制作用,建立了测定痕量Ti(Ⅳ)的光度法。测定范围为24~24μg/L,检出限为106×10-7g/LTi(Ⅳ)。结合萃取分离富集技术,方法用于测定人发及茶叶样品中的痕量Ti(Ⅳ),结果与标准值相符,加标回收率在95%~100%,RSD(n=6)为11%~20%。 相似文献
23.
催化分光光度法测定痕量钛 总被引:2,自引:0,他引:2
催化分光光度法测定痕量钛周之荣1吴伟华东地质学院应化系江西临川344000催化褪色光度法测定钛的报道较少[1],本文研究了痕量Ti(Ⅳ)催化过氧化氢氧化酸性铬蓝K褪色反应的影响因素,建立了测定痕量Ti(Ⅳ)的催化光度法,并用于测定植物及人发中钛。方法... 相似文献
24.
本文研究了以cHCl=8mol·L-1盐酸为移动相,以聚四氟乙烯负载的钽试剂-CHCl3为固定相反相萃取层析钛(Ⅳ)的新体系,柱上层析的钛用cHCl=3mol·L-1盐酸洗脱后经二安替比林甲烷光度法测定,不仅钛回收率可达100%,并可使钛(Ⅳ)与多种离子分离。能用于矿物岩石类复杂样品及其他物质中钛的分离富集与测定,方法简便快速。 相似文献
25.
The shear viscosities and 1 bar heat capacities of glasses and melts along the 67mol% silica isopleth in the system SiO2-Al2O3-Na2O-TiO2 have been determined in the temperature ranges 780-1140 K and 305-1090 K respectively. Anomalous behaviour of both these properties is observed for compositions rich in TiO2 and/or Al2O3, an observation attributed to liquid-liquid phase separation followed by anatase crystallization. For samples which do not show anomalous behaviour, it is found that the partial molar heat capacity of the TiO2 component previously determined in Al-free compositions reproduces our heat capacities to within 1.3%. Viscosity data show that addition of TiO2 tends to increase viscosity and melt fragility at constant temperature. Furthermore, heat capacity and viscosity data may be combined within the framework of the Adam-Gibbs theory to extract values of the configurational entropy of the liquids and qualitative estimates of the variation of the average energy barrier to viscous flow. Configurational entropy at 900K is inferred to decrease upon addition of TiO2, in contrast to previous results from Al-free systems. The compositional limit separating normal from anomalous behaviour, as well as the data for homogenous melts have been used to constrain the structural role of Ti in these samples. Our data are consistent with a majority of Ti in five-fold coordination associated with a titanyl bond, in agreement with previous spectroscopic studies. Furthermore, we find no evidence for a Ti-Al interaction in our samples, and we are led to the conclusion that Al and Ti are incompletely mixed, a hypothesis consistent with the observed reduction of configurational entropy upon addition of TiO2, suggesting an important role of medium range order in controlling the variations in thermodynamic properties. 相似文献
26.
F. S. Turalioglu H. Bayraktar 《Stochastic Environmental Research and Risk Assessment (SERRA)》2005,19(1):41-47
In the assessment of air quality, regional distribution and dispersion with distance are important, together with the variations of pollutants in time. On this occasion, the point cumulative semi-variogram (PCSV) method is used in order to find simply regional distribution of pollutants of Erzurum urban centre. This method is based simply on the summation of square differences in air pollutant concentrations between different sites. Monthly regional variation maps of Erzurum are constructed by finding radius of influence (for SO2, from 1000 m to 3500 m and, for TSP, 1000–2000 m) and PCSV scattering diagram data at different levels by using monthly average sulphur dioxide (SO2) and total suspended particulate (TSP) matter concentrations in 2001–2002 winter season. Consequently, the air pollution distribution of Erzurum is assessed. 相似文献
27.
Simultaneous in situ immobilisation of uranium (U) and radium (226Ra) by injectible amounts of grey cast iron (gcFe), nano-scale iron (naFe) and a gcFe/MnO2 mixture (1:1) was studied in batch and column tests. Both 0.5 g/L naFe and gcFe are effective in 226Ra and U removal from mine water, whereas MnO2 addition clearly increased the efficiency of gcFe for 226Ra and U immobilisation. In a column test with 0.6 wt% gcFe/MnO2 mixture (1:1), neither 226Ra nor U was detected in the effluent after replacement of 45 pore volumes. A sequential extraction under flow condition revealed 226Ra to be mostly occluded in manganese oxides. Uranium was mostly sorbed onto poorly crystalline iron hydroxides, but a significant part was found to be occluded in manganese oxides also. The results of this study suggest that MnO2 promotes iron hydroxide formation under slightly reducing environmental conditions resulting in an increased pollutant retention capacity. 相似文献
28.
基于主体功能区约束的大气污染物总量控制目标分配研究 总被引:1,自引:0,他引:1
考虑经济发展水平、污染物排放现状、污染物治理水平、空气质量,特别是国家主体功能区环境目标约束等因素,构建大气污染物排放总量分配的指标体系,用改进的等比例分配方法对2015年国家SO2,NOx总量控制目标进行区域分配。分配结果表明:SO2和NOx削减量大的省份主要集中在华北平原及其周围地区,这些地区污染物排放量大、空气质量较差;削减比例较大的地区主要集中在西部地区以及北京、天津2个直辖市,这些地区单位GDP能耗高、工业污染物去除率低、空气质量差;削减量相对较小的地区主要集中在西南和南部一些省份;削减比例较小的地区主要集中在中南部和南部几个省份,这些地区污染物排放量相对较少,空气质量好于其他省份。 相似文献
29.
Land surface temperature (LST) is an important aspect in global to regional change studies, for control of climate change and balancing of high temperature. Urbanization is one of the influencing factors increasing land surface and atmospheric temperature, by the emission of greenhouse gases (e.g. CO2, NO and methane). In the present study, LST was derived from Landsat-8 of multitemporal data sets to analyse the spatial structure of the urban thermal environment in relation to the urban surface characteristics and land use–land cover (LULC). LST is influenced by the greenhouse gases i.e. CO2 plays an important role in increasing the earth’s surface temperature. In order to provide the evidence of influence of CO2 on LST, the relationship between LST, air temperature and CO2 was analysed. Landsat-8 satellite has two thermal bands, 10 and 11. These bands were used to accurately to calculate the temperature over the study area. Results showed that the strength of correlation between ground monitoring data and satellite data was high. Based on correlation values of each month April (R2 = 0.994), May (R2 = 0.297) and June (R2 = 0.934), observed results show that band 10 was significantly correlating with air temperature. Relationship between LST and CO2 levels were obtained from linear regression analysis. band 11 was correlating significantly with CO2 values in each of the months April (R2 = 0.217), May (R2 = 0.914) and June, (R2 = 0.934), because band 11 is closer to the 15-micron band of CO2. From the results, it was observed that band 10 can be used for calculating air temperature and band 11 can be used for estimation of greenhouse gases. 相似文献
30.
许厂煤矿下组煤中蕴藏着较为丰富的瓦斯、二氧化碳资源。下组煤位于瓦斯风化带内,含瓦斯、二氧化碳和氮气等气体,瓦斯含量与埋藏深度呈正相关关系,主要存在低含量瓦斯、二氧化碳抽采率、二氧化碳资源化转换等技术方面的问题。从国家相关优惠政策、资源优势、煤与煤层气一体化开发技术、近水平长钻孔定向钻进技术、煤层压裂造缝技术、煤层注气增产技术和瓦斯、二氧化碳气体提纯技术等关键技术的发展程度,结合煤矿的下组煤层的开采方案,认为许厂煤矿有着较好的煤炭与瓦斯、二氧化碳一体化开发利用前景。 相似文献