共查询到18条相似文献,搜索用时 437 毫秒
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研究了Ni()-PAR在吐温80-硫酸铵-水体系中的最佳萃取条件,建立了水样中测定痕量镍的非有机溶剂液-固萃取光度法。在NH3·H2O-NH4Cl缓冲溶液中,金属配合物Ni()-PAR可被吐温80固相富集萃取,最大吸收波长为500nm,镍含量在0—1.0μg/mL范围内服从朗伯-比耳定律,表观摩尔吸光系数为6.345×104L·mol-1·cm-1。该法测定水样中镍含量,回收率可达96.3%—103.0%。 相似文献
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在硼砂-盐酸缓冲液中,Triton X-100/n-C5H11OH/n-C9H20/H2O微乳液或Triton X-100/H2O胶束体系中,水杨基荧光酮(SAF)与镍具有荧光猝灭特性,本文研究了微乳液介质体系中,以SAF作荧光剂,用荧光猝灭法测定微量镍的方法,实验结果表明,与相应的胶束介质体系比较,Triton X-100/n-C5H11oH/n-C9H20/H2O微乳液介质体系中,该法测定灵敏度高,选择性好,可直接用于水样中痕量镍的测定,测定结果令人满意。 相似文献
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硫酸钡吸光比浊法测定大蒜中大蒜素含量 总被引:3,自引:1,他引:2
用浓硝酸将大蒜中有机硫化物定量氧化成硫酸根,在聚乙烯醇介质中与钡离子反应生成稳定的硫酸钡悬浊液,吸光比浊法测定其硫酸根含量,从而换算出大蒜素含量.建立了吸光比浊法测定大蒜中大蒜紊含量的新方法,该法不需大蒜素标准样品,简单、快速、实用,结果与定硫法(重量法)基本一致. 相似文献
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用石墨炉原子吸收法测定掺质钆镓石榴石单晶中钴、铬、镍的含量,晶体中的钆不影响测定,但镓呈现背景干扰,文中对此进行了讨论。用氘灯扣除背景。钴、铬、镍含量为0.015%、0.037%、0.0057%时,变动系数分别为1.4%、1.9%、2.7%,检出限分别为2.5μg/g、0.87μg/g、2.0μg/g。 相似文献
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应用X射线显微CT(X-μCT)对正常及骨质疏松大鼠的骨小梁结构进行了分析,并与骨组织形态计量法的测量值进行了比较,探讨了X射线光谱技术在骨结构分析中的应用。实验对大鼠骨样品进行X-μCT扫描,扫描条件为 80 kVp,80 μA,360°旋转,帧平均4帧,角度增益 0.4°,分辨率14 μm。三维重建并分析了骨小梁结构,结构参数包括骨体积分数(BV/TV)、骨小梁厚度(Tb.Th)、骨小梁数量(Tb.N)以及骨小梁间隔(Tb.Sp)。结果表明,采用X-μCT分析不同组大鼠的骨小梁结构参数值之间存在显著差异(P<0.05),测定值与传统骨组织形态计量法的测定值显著相关,其中胫骨骨小梁BV/TV,Tb.Th,Tb.N,Tb.Sp的相关系数r分别为0.984,0.960,0.995,0.988,腰椎骨小梁各结构参数的相关系数分别为0.938,0.968,0.877,0.951。因此,X-μCT可以较好地呈现并区分正常骨组织、骨质疏松骨组织以及经雌激素治疗后骨组织的微观结构,可以实现对骨小梁结构参数的分析测定,与骨组织形态计量法相比是一种更精确、立体、快速且无损测量骨微结构和评价骨质量的方法。 相似文献
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Pipeline steels absorb different amounts of hydrogen during transportation of sour oil and gas. Since hydrogen-related damages such as hydrogen-induced cracking are strongly affected by hydrogen permeation behavior of steels, the purpose of this study determined to investigate hydrogen permeation behavior in API X-70 pipeline steel using electrochemical permeation method. The effect of heat treatment was also considered. It was found that hydrogen diffusivity increased by annealing the X-70 and it was decreased by normalizing. The condition was reverse for hydrogen apparent solubility. Finally, it was concluded that change in hydrogen diffusivity can be attributed to changes in grain size due to heat treatment. 相似文献
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Alaa S. Amin 《光谱学快报》2013,46(6):424-431
ABSTRACT A cloud-point extraction (CPE) process using the nonionic surfactant Triton X-114 to extract bismuth from aqueous solutions was investigated. The method is based on the complexation reaction of Bi(III) with 4-(2-benzothiazolylazo)2,2′-biphenyldiol (BTABD) and micelle-mediated extraction of the complex. The optimal extraction and reaction conditions (e.g., pH, reagent concentration, surfactant concentration, and effect of time) were studied. The analytical characteristics of the method (e.g., linear range, molar absorptivity, Sandell sensitivity, optimum Ringbom concentration ranges, limits of detection and quantification, preconcentration factor, and improvement factors) were obtained. Linearity was obeyed in the range of 2.50–85.0 ng mL?1 of Bi(III) ion. The detection limit of the method was 0.75 ng mL?1 of Bi(III) ion. The interference effect of some anions and cations was also tested. The method was applied to the determination of bismuth in environmental water, human hair, and urine samples. 相似文献
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采用液态离子交换法制备了不同负载量的镍改性ZSM-5分子筛催化剂,并考察了上述催化剂的微观结构和物理化学特性及其在NH3-SCR反应中的催化性能。结果表明:在负载量<10.9%时镍在分子筛中具有高度的分散性,而随着镍负载量的进一步增加,分子筛表面开始出现较大的NiO颗粒;镍元素只以+2价存在于分子筛催化剂中;在NH3-SCR反应中,镍负载量低于14.9%时,增加镍负载量将提高催化剂的低温活性;当反应温度超过300℃时,高温催化中心开始起作用,但随镍负载量的增加,高温活性开始下降时的温度逐渐降低。 相似文献
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The effect of tensile stress on diffusion was studied by the diffusion couple method. A diffusion couple was prepared by electroless plating a nickel thin layer on the round notch surface of a compact tension-type specimen of 20% cold-worked Type 316 stainless steel. The couple was diffused at 450°C for 4003?h under the maximum tensile stress of 553?MPa in the load direction. A rapid diffusion coefficient of nickel in the Type 316 stainless steel was observed at the high tensile stress zone that was 6.5 times faster than that at the low-stress zone. 相似文献