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本文以二苯基甲酮的KBr压片为标样,在Bruker IFS 120HR付里叶变换红外光谱仪上系统考察了该仪器折一些重要操作参数(光源光栏、切趾函数、扫描速度)对光谱质量(信噪比,分辨率)的影响。从而获得了测样时的优化操作条件。 相似文献
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Paul?LanganEmail author Narayanasami?Sukumar Yoshiharu?Nishiyama Henri?Chanzy 《Cellulose (London, England)》2005,12(6):551-562
Synchrotron X-ray data have been collected to 1.4 Å resolution at the NE-CAT beam-line at the Advanced Photon Source from fibers of cellulose Iβ and regenerated cellulose II (Fortisan) at ambient temperature and at 100 K in order to understand the effects of low temperature on cellulose more thoroughly. Crystal structures have been determined at each temperature. The unit cell of regenerated cellulose II contracted, with decreasing temperature, by 0.25%, 0.22% and 0.1% along the a, b, and c axes, respectively, whereas that of cellulose Iβ contracted only in the direction of the a axis, by 0.9%. The value of 4.6×10?5 K?1 for the thermal expansion coefficient of cellulose Iβ in the a axis direction can be explained by simple harmonic molecular oscillations and the lack of hydrogen-bonding in this direction. The molecular conformations of each allomorph are essential unchanged by cooling to 100 K. The room temperature crystal structure of regenerated cellulose II is essentially identical to the crystal structure of mercerized cellulose II. 相似文献
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建立了高效液相色谱-线性离子阱/静电场轨道阱高分辨质谱(HPLC-LTQ/Orbitrap MS)筛查和确证生态纺织品中致癌染料的方法。样品在水浴(95 ℃)中用吡啶/水(1/1, v/v)振荡(150 r/min)提取,上清液过聚四氟乙烯(PTFE)滤膜后,CAPCELL PAK C18色谱柱(100 mm×2.0 mm, 5 μm)分离,以乙腈和5 mmol/L乙酸铵水溶液(含0.01%甲酸)、乙腈和5 mmol/L乙酸铵水溶液分别作为正、负电喷雾离子化(ESI)模式的色谱流动相梯度洗脱。在m/z 200~800范围内进行一级质谱全扫描。以准分子离子峰的精确质量数和提取的色谱图峰面积进行筛查分析和定量,以保留时间和数据依赖扫描(data-dependent scan)模式获得的子离子质谱图进行定性确证。9种染料的质量准确度小于5×10-6(5 ppm),线性良好,相关系数大于0.99,方法检出限为0.125~25 mg/kg。3个添加水平的回收率范围为62.13%~116.28%,相对标准偏差小于15%。应用该方法检测了棉、涤纶及混纺纤维等20余件纺织品样品中的致癌染料残留。该方法准确、可靠。 相似文献
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The study of γ‐neutrons attenuation and mechanical characteristics of modified concrete are vital and crucial parameters for the construction of civilian radiological, nuclear shielding, and/or shelters. In this work, fifteen samples of ordinary concretes with five different additives; steel fibers, polypropylene, silica fume, and fly ash, with variation of cement percentages, were prepared and used for performing the mechanical and radiation attenuation investigations. The compressive strength, tensile strength, slump test, bulk density, and water permeability were also carried out for the prepared concrete mixes. Collimated coherent beams from 60Co and Pu‐Be fast neutron sources were used to check the radiation penetrability through the syntheized mixed concrete‐additives. Very sensitive and well calibrated gamma‐neutron pulse shape discriminating spectrometer with its electronic componenets and stilbene organic detector and 3′′ × 3′′ NaI scintillation crystal was used to measure the radiation before and after attenuation and transmission. The integrated fast neutron removal macroscopic cross section (Σr) and linear attenuation coefficient of total gamma rays (μ) were calculated for all the analysed concrete mixes. The results of measurements, tests, analyses and calculations are given and explained. The investigated modified concrete mixes show good workability and properties from the view point of mechanical loads and γ‐fast neutrons penetrability and resistance. These results can be used for shielding and sheltering design. 相似文献
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Hao Cheng Xiaoguang Gao Jian Jia Dexin Zhang Dongjie Zhao 《International journal of environmental analytical chemistry》2013,93(3):279-288
A simple and rapid method using a microhotplate-based preconcentrator and an ion mobility spectrometer (IMS) is proposed for the detection of malathion in water. The preconcentrator is prepared by micro-electro-mechanical system (MEMS) process. Coated with Polydimethylsiloxane (PDMS), it has the advantages of solvent-less, low energy cost, self-heating and ease to combine with IMS. The operating conditions of the preconcentrator-IMS system, such as extraction time, extraction temperature, agitation speed and desorption temperature, were optimised. Using the preconcentrator, the sampling procedure can be simplified and the detection limit of the system can be decreased. A linear relationship between the IMS response and the concentration of the analyte solution was verified. The malathion detection limit based on 3 times the baseline noise is 0.43?µg?L?1 and the total analysis time is less than 30?minutes. 相似文献
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光谱实验室的建设和管理 总被引:1,自引:0,他引:1
阐述冶金、铸造等行业用于金属成分分析的直读发射光谱仪实验室的建设和管理。从仪器的调研、选型,实验室选址,基础设施设备的准备,仪器的安装、调试、验收、日常分析,实验室管理等几个方面,分别作了介绍。 相似文献