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本文探讨了用XRF法分析不锈钢时,用个别交叉项系数校正Cr,Fe,Ni之间的交叉效应,从而有效地修正了它们之间的吸收-增强效应,使分析结果得到改善。最大误差不超过0.5%,与C-Q方程相比,该法计算简便,具灵活性和实用性,可推广使用。 相似文献
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在交叉缔合的均相状态方程的基础上,结合密度梯度理论(density gradient theory,DGT),建立了适用于CO2-甲醇和CO2-乙醇二元体系界面性质研究的状态方程,对CO2-乙醇体系表面张力的关联结果与实验值吻合良好.阐明了CO2分子与甲醇分子和乙醇分子之间的交叉缔合作用对二元体系表面张力计算结果的影响,以及界面相中CO2与醇羟基之间的交叉缔合与温度和压力之间的关系. 相似文献
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以原子的电负性χP和极化度α为基本参数, 估算卤代甲烷CHnY4−n−mZm(Y, Z=F, Cl, Br, I) C 1s电子电离能的电荷效应和松弛效应. 电荷效应由C—H和C—Y(Z)键两端原子的电负性差来度量, 松弛效应由碳原子带的电荷乘上氢和卤素原子极化度来衡量, 进而用电荷效应和松弛效应一起表达卤代甲烷中C 1s电子电离能的静电-松弛屏蔽效应ΔSi. 将ΔSi代入类-Slater模型, 得到卤代甲烷中C 1s电子电离能E1,C的估算方程, 该方程的相关系数r=0.99987, 对27个卤代甲烷的计算值与实验值之间的平均绝对误差仅为0.038 eV, 小于实验误差0.1 eV. 同时, 用留一法(leave-one-out)进行交叉验证(相关系数rcv=0.99977, 预测值与实验值之间的绝对平均误差只有0.049 eV), 结果表明所得方程具有良好的预测能力和稳定性. 相似文献
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自旋交叉配合物在温度、压力、光照和磁场等刺激下可以发生高低自旋态之间的可逆转变,通常还伴随着颜色、体积和电导率变化以及热滞等效应,因此这类材料在光热开关、传感器、显示和存储等领域具有潜在的应用.由于可以获得高质量的超洁净薄膜,高真空蒸镀工艺常用于分子电子学与分子磁学等的器件制备,目前报道的可蒸镀自旋交叉配合物种类较少,大大限制了自旋交叉配合物的器件应用.针对可蒸镀自旋交叉配合物的薄膜与器件进行了系统的综述,介绍了几种主要的适于高真空蒸镀的自旋交叉配合物,结合不同的表征手段分析了衬底对分子薄膜自旋转变特性的影响,并针对相关的概念性器件进行了讨论,最后对自旋交叉配合物在器件应用中存在的难点和未来的发展趋势进行了展望和评述,希望能够为自旋交叉领域的器件应用提供一些借鉴. 相似文献
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锥形交叉可以通过几何相效应影响核动力学.在过去的一些年里关于锥形交叉的理论有大量的发展和进步,本文综述了分子反应动力学领域针对几何相效应研究的一些理论成果.介绍了分子反应动力学中与几何相效应直接相关的一些最新成果,同时也对这些重要结果进行了解释.我们相信几何相效应将会在非绝热化学中发挥最重要的作用. 相似文献
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在统计缔合流体理论(statistical associating fluid theory,SAFT)的基础上,将二氧化碳(CO2)处理为似缔合分子,考虑醇羟基之间的自缔合作用,以及CO2分子与醇羟基之间的交叉缔合作用,提出了适用于CO2-醇类体系的交叉缔合模型.应用该模型研究了CO2-甲醇和CO2-乙醇体系从低温低压到高温高压的相平衡性质.p-x和p-ρ相图的计算值与实验值吻合良好.研究表明,考虑CO2与甲醇和乙醇分子之间的交叉缔合对Helmholtz自由能的贡献,可显著改善相平衡性质的计算结果,并避免模型对低温区间中三相平衡和三相点的错误预测. 相似文献
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用中压汞灯(λ > 300 nm)照射4-苯乙烯基吡啶、2-苯乙烯基苯并噁唑和5-苯基-2-苯乙烯基噁唑三种杂芳基乙烯单体中任意两种的硫酸水溶液,得到三种交叉二聚体.用高效液相色谱跟踪研究了交叉光二聚反应,发现每组反应生成三种光二聚体,其中二种为单体自身的光二聚体,而另外一种是两种不同单体的交叉光二聚体.交叉二聚体通过柱色谱分离得到,其顺式头对尾结构经紫外、红外、氢谱、碳谱和元素分析确定.用紫外光谱和高效液相色谱跟踪研究了交叉光二聚体的稀溶液在低压汞灯(λmax=254 nm)照射下的光解反应.研究发现交叉二聚体能够彻底发生光解,首先生成原来的反式单体,所生成的反式单体容易发生异构化而生成顺式单体,最终建立起反顺异构化平衡. 相似文献
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建立了一种在氮气和氢气的还原性混合气氛和1100 ℃条件下加热商业不锈钢箔(304)制备MnCr2O4尖晶石纳米线的简单方法, 并研究了不同气氛对纳米线生长的影响. 研究发现, 混合气体中氢气含量的变化会影响纳米线的形貌和产率; 而氧化性气氛(如空气)下则得不到纳米线. 在还原性气氛下, Mn和Cr原子可以和反应室内残留的痕量氧反应生成MnCr2O4尖晶石, 而Fe和Ni原子不能被氧化, 但是Fe和Ni可以起到催化纳米线生长的作用, 纳米线的生长机理属于自催化性的气-液-固(VLS)机制. 相似文献
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《Spectrochimica Acta Part B: Atomic Spectroscopy》2005,60(2):249-252
Steel with a paint layer was analyzed with a hand-held X-ray fluorescence spectrometer. When the 0.5 mm thick paint layer was composed mainly of light elements, alloying elements in steel such as Fe, Cr, Ni, W, and Mo were easily detected. 0.2% Mo in steel was detectable even if the paint contained Ti or Fe as a main element. The signal intensity of each element in steel decreased exponentially when the paint thickness increased, and the degree of decrease depended on the X-ray energy. Therefore the peak intensity for non-painted steel could be calculated from the paint thickness. The paint thickness was estimated from the intensity ratio Fe Kβ/Kα or W Lβ/Lα. When a paint of Ti (0.07–0.49 mm thick) was used, the peak intensities of the Fe Kα, Cr Kα, Ni Kα, and Mo Kα lines for non-painted steel were estimated by using the intensity ratio Fe Kβ/Kα, with errors of less than 30%. The content of each element in steel is estimated when the fluorescent X-rays are detectable by analysis of painted steel without removing the paint layer. On-site screening of painted steel can be performed on the basis of the alloy composition estimated by analysis with a hand-held XRF spectrometer. 相似文献
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不同炊具铁、铝或镍、铬溶出量的测定 总被引:1,自引:0,他引:1
常用炊具铁、铝和不锈钢锅分别以水、水加醋煮沸10min后,用原子吸收分光光度法测定3种锅加水对应无奈的溶出量(mg/L)分别为铁11.60、铝21.41、镍0.06和铬0.07,而水加醋则其溶出量均明显增加,为加水的2.0-4.5倍。 相似文献
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《Electrochemistry communications》2001,3(9):494-499
The Fe–Cr–Ni and Fe–Cr–Ni–Ta alloy films were deposited on quartz substrates by magnetron-sputtering using targets of AISI 316 stainless steel and in combination with pure tantalum. The conventional melting of the Fe–Cr–Ni–Ta alloy formed is virtually impossible because the melting point of tantalum is higher than the boiling points of the other components. Elemental content of the films was determined by XPS analysis. Corrosion behaviour of both alloy films was studied in 5% NaCl and 10 M HCl by electrochemical quartz crystal microgravimetry (EQCM), electrochemical impedance spectroscopy (EIS) and dc-voltammetry. The corrosion resistance of Fe–Cr–Ni–Ta appeared to be significantly higher than that of Fe–Cr–Ni in both neutral (5% NaCl) and strongly acidic (10 M HCl) media. The Fe–Cr–Ni–Ta specimen exhibited an extremely high corrosion resistance in 10 M HCl, where the corrosion rates were about one order of magnitude lower than those of Fe–Cr–Ni in neutral solution. EQCM measurements in NaCl solution indicated accumulation of corrosion products on the Fe–Cr–Ni–Ta surface, which was evident from a distinctive increase in electrode mass. By contrast, the mass of the tantalum-free alloy film decreased with a constant rate, which indicated alloy dissolution to prevail. The corrosion current calculated from the mass decrease was in good agreement with that derived from voltammetric measurements. The EQCM data showed that the corrosion resistance of the Fe–Cr–Ni–Ta alloy film in 10 M HCl was about two orders of magnitude higher than that of the Fe–Cr–Ni. 相似文献
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Fe3Al and Cr18-Ni8 stainless steel were diffusion-bonded in vacuum and a Fe3Al/Cr18-Ni8 interface with reaction layer was formed. Microstructure in the reaction layer at Fe3Al/Cr18-Ni8 interface was analyzed by means of scanning electron microscope (SEM) and electron probe micro-analyzer (EPMA). The growth of reaction layer with heating temperature (T) and holding time (t) was researched. The results indicate that FeAl, Fe3Al, Ni3Al, and alpha-Fe (Al) solid solution are formed in the reaction layer. These phases are favorable to promote the element diffusion and to accelerate the formation of the reaction layer at Fe3Al/Cr18-Ni8 interface. The growth of reaction layer obeys the parabolic law and its thickness (X) is expressed by X2 = 7.5 x 10(-4)exp(-83.59/RT)(t - t0). 相似文献
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应用电化学动电位再活化法(EPR法)评价不锈钢复合板和低铬铁素体不锈钢的晶间腐蚀敏感性. 结果表明,以电化学动电位再活化法测得的反向扫描与正向扫描电流最大值之比(ir / ia)评价堆焊不锈钢复合板00Cr17Ni14Mo2/20R复层晶间敏感性与传统H2SO4-CuSO4-Cu法测定的结果吻合甚好;评价爆炸复合板复层06Cr13R低铬铁素体不锈钢晶间腐蚀敏感性与草酸浸蚀法测定的也一致. 说明该法可以成功用于定量、定性地评价不锈钢复合板和低铬铁素体不锈钢的晶间腐蚀敏感性. 相似文献
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T. Green S. Biegalski S. O’Kelly G. Sayre 《Journal of Radioanalytical and Nuclear Chemistry》2008,276(1):279-284
Stainless steel flux wires were used to determine the neutron energy spectra and total flux during the Reactor Accelerator
Coupling Experiments (RACE) at The University of Texas at Austin. A LINAC electron accelerator produced 20 MeV electrons at
a power of 1.6 kW, which struck a tungsten-copper target to produce bremsstrahlung radiation and photoneutrons. The neutrons
produced in the target were multiplied by the subcritical core of a Triga reactor. The purpose of the RACE experiments is
to develop a sub-critical accelerator driven system that would be capable of transmuting actinides from spent fuel. Flux measurements
were made with 1.58 mm diameter stainless steel wires placed throughout the core between the fuel rods and cadmium covered
and uncovered gold and indium foils above the target. The MAXED and GRAVEL computer codes were used to perform the spectrum
unfolding. The composition of the stainless steel wires was determined using neutron activation analysis with comparators
prior to the flux measurement. The reactions measured in the stainless steel to determine the flux were 50Cr(n,γ)51Cr, 58Ni(n,p)58Co, 54Fe(n,p)54Mn, and 58Fe(n,γ)59Fe. Flux measurements agreed well with an MCNP simulation of the experiment. 相似文献
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应用光电直读光谱法测定了不锈钢(CD4MCu)中碳、镍、铬、铜及钼5种元素。通过下述三项措施提高了方法的准确度和精密度:共存元素的干扰校正;增加制作各元素的标准工作曲线时所用的标准样品数,用了两套标准共13块光谱分析用标准样品;选择样块上合适部位作为光谱激发点。上述5种元素的测量范围(质量分数)依次为0.02%~0.35%,3.50%~28.0%,6.50%~32.0%,0.05%~5.0%及0.05%~4.0%。对方法的精密度做了试验,测得相对标准偏差(n=11)为碳4.8%,镍、铬、钼0.4%,铜2.3%。应用此方法分析了5个不锈钢(CD4MCu)样品,所测得数据与用GB标准中化学法所测得的结果完全一致。 相似文献