排序方式: 共有112条查询结果,搜索用时 15 毫秒
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差分吸收光谱法测量大气痕量气体浓度误差分析及改善方法 总被引:8,自引:2,他引:6
差分吸收光谱技术(DOAS)中采用线性最小二乘拟合方法,用痕量气体标准差分吸收截面对测量得到的差分吸收光谱进行拟合,得出大气中痕量气体的浓度.计算结果的准确性不仅取决于光谱的测量精度,而且受标准差分吸收截面以及仪器函数和温度等诸多因素的影响.详细地分析了计算误差的产生原因,提出了用高浓度样品池得到标准吸收截面的方法,针对光谱固有结构,以及温度对标准吸收截面的影响,改进了浓度反演算法.大量的实验表明,综合运用上述方法,即便对低浓度的样气,相对测量误差也能降低到10%以下. 相似文献
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Li-Na Xiang Li-Juan Chen Lin Tan Chong Zhang Fu-Hu Cao Song-Tao Liu Yan-Mei Wang 《中国化学快报》2013,24(7):597-600
A novel polydopamine-graft-poly(2-methyl-2-oxazoline)(PDA-g-PMOXA) coating was prepared by immobilizing poly(2-methyl-2-oxazoline)(PMOXA) onto material surfaces through polydopamine (PDA) anchored coating for the first time.And then,the chemical composition,hydrophilicity,and protein-resistant properties of the PDA-g-PMOXA coating were studied using X-ray photoelectron spectroscopy(XPS),contact angel(CA) test,surface plasmon resonance(SPR),and quartz crystal microbalance with dissipation(QCM-D) measurement.Finally,the coating was applied to the capillary inner surface for protein separation by capillary electrophoresis(CE). 相似文献
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Chen Li Wendong Wang Congying Xu Yuanxu Liu Bo He Chusheng Chen .CAS Key Laboratory of Materials for Energy Conversion University of Science Technology of China Hefei Anhui China 《天然气化学杂志》2011,(4):345-349
The double perovskite oxides Sr2Mg1-xF exMoO6-δ were investigated as catalysts for the methane oxidation.The structural properties of catalysts were characterized in detail by X-ray diffraction,X-ray photoelectron spectroscopy and X-ray absorption spectroscopy.The catalytic property was strongly influenced by the Fe substitution.The relation between catalytic performance and the degree of Fe substitution was examined with regard to the structure and surface characteristics of the mixed oxides.The Fe-containing catalysts exhibited higher activity attributable to the possible(Fe2+,Mo6+) and (Fe3+,Mo5+)valency pairs,and the highest activity was observed for Sr2Mg0.2Fe0.8MoO6-δ.The enhancement of the catalytic activity may be correlated with the Fe-relating surface lattice oxygen species and was discussed in view of the presence of oxygen vacancies. 相似文献
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各向异性本构关系在板料成形数值模拟中的应用 总被引:7,自引:0,他引:7
对几种能表达面内各向异性的屈服准则Hill、Barlat-Lian、Barlat进行了比较。以弹性变形服从各向同性广义虎克定律的情况下,给出了基于张量算法推导的弹塑性本构关系的一般表达式,并由此导出了相应屈服准则的弹塑性本构关系的显式表达。借助ABAQUS软件本构模块用户子程序接口,分别实现了这些屈服准则在ABAQUS的嵌入。以模拟方形盒的拉延过程为例,分析了不同的屈服准则在板料成形过程数值模拟中的应用。模拟结果表明,基于弹塑性本构关系一般表达所列出的相应屈服准则的显式表达式是正确的;在采用壳元来模拟板料成形时,采用Barlat准则的模拟结果和采用Barlat-Lian准则的结果差别不大。 相似文献
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A high detection efficiency calorimeter which is used to detect γ-rays with energies from 1 MeV up to 10 MeV as well as light charged particles has been proposed. Design of the geometry, results of the crystal tests and Monte Carlo simulations are presented in this paper. The simulation results confirm that the calorimeter can obtain high detection efficiency and good energy resolution with the current designed geometry. And the calorimeter is competent for the future External Target Facility (ETF) experiments. 相似文献
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ASIF Anila 《中国科学B辑(英文版)》2011,(9)
A novel hyperbranched poly(urethane-tetrazole)(HPUTZ) was synthesized via the A2+BB2' approach using hexadiisocyanate(HDI) and 3-(bis-(2-hydroxyethyl)) aminopropyltetrazole(HAPTZ).The molecular structure was characterized by FTIR and 1H NMR spectroscopy.The number average molecular weight was measured to be 1.05×104 g/mol with a polydispersity of 1.27 by GPC analysis.The HPUTZ was further cured by the semi-adduct(PEG-IPDI) from polyethylene glycol(PEG) reacting with isophorone diisocyanate(IPDI) to form th... 相似文献
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Coherent X-ray microscopy has advanced towards higher-energy, more brilliant sources over the past decade since its demonstrations, and many advancements have been made towards optimizing this imaging technique. Here we present both the experimental instrument for obtaining diffraction patterns and the primary reconstruction of yeast cell 2D projection. In addition, the characteristics of the existing optics at BL29XUL of SPring-8 Facility and the method of image reconstruction are discussed. 相似文献