排序方式: 共有89条查询结果,搜索用时 15 毫秒
71.
Investigation of sulfur speciation in particles from small coal-burning boiler by XANES spectroscop 总被引:1,自引:0,他引:1
Sulfur K-edge X-ray absorption near-edge structure (XANES) spectroscopy was employed to study the speciation of sulfur in raw coal, ash by-product and fine particulate matter from a small coal-burning boiler. By means of least square analysis of the XANES spectra, the major organic and inorganic sulfur forms were quantitatively determined. The results show that about 70% of the sulfur in raw coal is present as organic and a minor fraction of the sulfur occurs as other forms: 17% of pyrite and 13% of sulfate. While in bottom ash, fly ash, and PM2.5, the dominant form of sulfur is sulfate, with the percentage of 80,79 and 94, respectively. Moreover, a number of other reduced sulfur including thiophenic sulfur, element sulfur and pyrrhotite are also present. During coal combustion, most of organic sulfur and pyrite were oxidized and released into the atmosphere as SO2 gas, part of them was converted to sulfate existing in coal combustion by-products, and a small part of pyrite was probably reduced to elemental sulfur and pyrrhotite. The results may provide information for assessing the pollution caused by small boiler and developing new methods for the control of SO2 pollution. 相似文献
72.
Transfer characterization of sulfur from coal-burning emission to plant leaves by PIXE and XANES 总被引:1,自引:0,他引:1
The impact of coal-burning emission on sulfur in camphor leaves was investigated using Proton Induced X-ray Emission (PIXE) and synchrotron radiation technique X-ray Absorption Near-Edge Structure (XANES) spectroscopy. The PIXE results show that the sulfur concentrations in the leaves collected at the polluted site are significantly higher than those in controls. The Sulfur XANES spectra show the presence of organic (disulfides, thiols, thioethers, sulfonates and sulfoxides) and inorganic sulfur (sulfates) in the leaves. The inorganic sulfur in the leaves of camphor tree polluted by coal combustion is 15% more than that of the control site. The results suggest that the long-term coal-burning pollution resulted in an enhanced content of the total sulfur and sulfate in the leaves, and the uptake of sulfur by leaves had exceeded the metabolic requirement of plants and the excess of sulfur was stored as SO42-. It can monitor the sulfur pollution in atmosphere. 相似文献
73.
74.
75.
天文观察用超软X射线探测器的标定 总被引:1,自引:0,他引:1
在北京同步辐射装置3W1B光束线上,对天文观测用超软X射线(0.2keV—3.5keV)正比计数管探测器进行了系统地标定.得到了正比计数管的死时间、计数率坪曲线、能量线性、能量分辨、窗材料透过比曲线;借助于已标定过的光电二极管探测器,测量了正比管探测器的能量响应效率,标定不确定度在10%—18%之间.另外,还对正比管系统在卫星上的六道记录和在实验室里的多道记录进行了对比,两种记录方式符合得很好. 相似文献
76.
Nanoscale carbon tubules deposited in anodic aluminium oxide template: a study of soft x-ray transmission 下载免费PDF全文
Well-aligned, catalyst-free nanoscale carbon tubules array was prepared by organic compound vapour deposition method using anodic aluminium oxide (AAO) as a template. The experiment of soft x-ray channelling in such carbon tubules array deposited in AAO template was performed at Beijing Synchrotron Radiation Facility. The transmission of x-rays in carbon tubules array with AAO template support was found even higher than that in bare AAO template at high-energy part of energy spectrum though the porous area of the former was smaller than that of the latter. A qualitative explanation is presented to interpret our results. 相似文献
77.
Measurement of integral diffraction coefficients of crystals on beamline 4B7 of Beijing Synchrotron Radiation Facility 下载免费PDF全文
Integral diffraction coefficients of the crystal are the essential data of a crystal spectrometer which is extensively used to measure quantitative x-ray spectra of high temperature plasmas in kilo-electron-volt region. An experimental method has been developed to measure the integral diffraction coefficients of crystals on beamline 4B7 of Beijing Synchrotron Radiation Facility. The integral diffraction coefficients of several crystals including polyethylene terephthalate (PET), thallium acid phthalate (TlAP) and rubidium acid phthalate (RAP) crystals have been measured in the x-ray energy range 2100--5600 eV and compared with the calculations of the 'Darwin Prins' and the 'Mosaic' models. It is shown that the integral diffraction coefficients of these crystals are between the calculations of the 'Darwin Prins' and the 'Mosaic' models, but more close to the `Darwin Prins' model calculations. 相似文献
78.
以十二胺和十八胺、磷酸二甲酯和磷酸二丁酯为原料合成系列磷酸酰胺类P-N型极压抗磨添加剂,用四球摩擦磨损评价了其添加到聚乙二醇(PEG-400)中的摩擦学性能,并用X射线吸收精细结构光谱(XANES)对所形成的摩擦膜进行了表面分析,初步探讨了该类添加剂的摩擦化学作用机理.摩擦学性能评价结果表明:所合成的P-N型添加剂添加于聚乙二醇(P-EG)润滑液中都具有良好的摩擦学性能,其中烷基链较短的PN1表现出优异的抗磨和耐极压特性.XANES分析结果显示:该类P-N型添加剂在PEG润滑液生成的摩擦膜主要有吸附层和反应层组成,在反应层中,磷元素主要以磷酸盐和聚磷酸盐形式存在. 相似文献
79.
80.