共查询到19条相似文献,搜索用时 156 毫秒
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利用沉淀分离、氧化 -还原、萃取和分光光度法测定 KIO3 - KI- KBr O3 - KBr混合体系中各组分含量。实验设计方案对实验综合设计以及复杂体系中各组分测定具有参考价值。 相似文献
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紫外光谱法同时测定卤水海产品中I和IO_3~- 总被引:1,自引:0,他引:1
样品中I-被溴水氧化成IO-3,用甲酸除去多余的溴水,在磷酸介质中IO-3与过量的I-生成I-3;样品中的IO-3在磷酸介质中直接与加入的过量I-生成I-3,I-3在350和288nm具有强吸收,且吸光度与I-3的浓度在一定的范围内具有线性关系。通过测定样品氧化前后的吸光度分别得到样品中I-和IO-3总量以及IO-3的量,差减法得到I-的量,建立了自身紫外光谱法快速方便地测定卤水和海产品中的I和IO-3。讨论了溴水、甲酸、磷酸和碘化钾的加入量以及光照、反应时间、反应温度对测定的影响,优化试剂条件是:对测定I-的体系,加入3%溴水溶液2滴,10%甲酸溶液0.5mL,20%磷酸溶液4mL,100g·L-1 KI溶液1mL;对测定IO-3的体系,加入20%磷酸溶液0.2mL,100g·L-1 KI溶液1mL。室温避光条件下反应30min测定体系吸光度。在优化条件下,I和IO-3的浓度分别在0~1.2mg·L-1与0~1.5mg·L-1的范围内符合朗伯-比尔定律。对样品空白平行测定12次,得到I-和IO-3的检出限分别是1.54和14.8μg·L-1。对0.8mg·L-1的I和IO-3平行测定12次,相对标准偏差分别是0.097%和0.067%。用建立的方法直接测定了扎布耶卤水、洪峰地下卤水中的I-和IO-3,并且采用碱式消解测定了海带、紫菜、海白菜中I-和IO-3,同时进行了样品加标回收实验,I-和IO-3回收率均在80%~120%之间,测定结果符合分析化学检测要求。 相似文献
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1-乙酰乙酰基-3-甲基吲哚对稀土离子能量传递过程研究 总被引:1,自引:0,他引:1
通过1-乙酰乙酰基-3-甲基吲哚(I3MK)与各种稀土离子在77K乙醇刚性溶液体系中的荧光光谱、磷光光谱的测定,进行了I3MK向稀土离子能量传递过程的静态分析;从I3MK和I3MK-Tb(Ⅲ)体系的荧光寿命、磷光寿命、量子产率,时间分辨光谱等,计算了各主要能量传递过程的速率常数和能量传递效率,进行了该体系能量传递过程的动态分析,提出了Perrin公式的修正参数,讨论了I3MK-Tb(Ⅲ)体系的能量传递机理. 相似文献
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微波消-石墨炉原子吸收法测定鲨鱼肝脏中的痕量镉 总被引:1,自引:0,他引:1
翁棣 《光谱学与光谱分析》2006,26(11):2147-2149
采用石墨炉原子吸收法直接测定鲨鱼肝脏中的痕量镉,试验发现,在HNO3-H2SO4-HClO4体系、HNO3-H2O2体系、HCl-HNO3体系、HF-HClO4体系中,以HF-HClO4体系消化效果最佳,经试验,0.2 g样品用1 mL HF,2 mL HClO4消溶效果较好.以HF-HClO4体系为消化试样、微波消解,用Pd(NO3)2作基体改进剂,灰化温度1 000℃,原子化温度2 200℃.该方法相对标准偏差为1.5%,标准物质测定值在其推荐值范围内,该方法快速、简便、准确. 相似文献
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探讨了电感耦合等离子体-原子发射光谱法(ICP-AES)测定铬质引流剂中Cr2O3、Al2O3、Fe2O3和MgO的分析条件.试样经过氧化钠熔融分解,盐酸酸化,采用内标加入法,利用ICP光谱仪于所推荐的波长处,测量溶液中铬、铝、铁、镁元素对钇内标元素的相对强度,根据标准溶液绘制的校准曲线计算出待测元素氧化物的质量分数.对该方法进行精密度试验,相对标准偏差(RSD,n=8)均小于1.0%,本测试方法简单、快速、精度高,将该方法用于铬质引流剂中Cr2O3、Al2O3、Fe2O3和MgO含量的测定,取得满意效果. 相似文献
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Jiazhu Hu 《Journal of sound and vibration》2010,329(19):3972-3998
This paper presents an experimental study of the nonlinear dynamic characteristics of taut steel cables using a 3-D motion analysis system. In the experiment, the taut cables have one end fixed and the other end subject to harmonic vertical excitation. The 3-D motion analysis system can simultaneously record (with high resolution) the instant 3-D coordinates of the multiple markers fixed on a vibrating cable; this distinguishes it from other experimental systems used in vibration studies, in which the vibration of only one single point can be recorded during each individual testing. With the 3-D motion analysis system, this experimental study presents a distinctive interpretation of the dynamic characteristics of taut cables in spatial domain (based on the mode-shape information of the entire cable), in addition to one in time domain (based on real-time traces of one single point). This paper introduces the 3-D motion analysis system and experimental setup, discusses practical experimental procedures, and presents a detailed analysis of three sets of experimental vibration data of three taut steel cables with different small sags. The frequency response curves were obtained for three cables. For one of the three taut cables, more informative vibration data were recorded; this cable was studied in greater detail via modal analysis using a modal decomposition technique and nonlinear time-series analysis. 相似文献
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采用微乳液法合成了Ce3 ,Tb3 单掺和双掺KZnF3纳米晶。分析了样品的结构与形态,结果表明,所合成的样品均为单相,颗粒粒度分布均匀。讨论了光谱特性,并与高温固相法合成的产物作了对比。研究发现,KZnF3:Ce3 纳米晶的发射光谱与体相多晶相比,最强峰位置红移约35nm;在KZnF3纳米晶双掺体系中存在Ce3 →Tb3 能量传递,尤其是Tb3 的5D4→7F5跃迁发射显著增强,有望成为一种有发展前途的绿色荧光材料。 相似文献
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建立光学投影层析三维成像系统,该系统包括光学成像、图像采集、断层重建及三维显示,重建算法为滤波反投影算法.实验结果表明:利用该系统得到的重建图像与样品的形状吻合,重建结果边缘清晰,伪迹较小. 相似文献
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Up-conversion luminescence have been studied on Yb3+-Er3+ co-doped fluoride samples. Two infrared lasers with wavelength of 930 nm and 858 nm are carefully chosen as excitation sources. The experimental results suggest direct cooperation sensitization up-conversion rather than two-step sensitization up-conversion is responsible for the increased population of 2H11/2 (Er3+) and thus the increased green emission in the region 514~574 nm in Yb3+-Er3+ co-doped system. 相似文献
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采用均相沉积法制备了不同Er3+离子浓度掺杂的Y2O3纳米晶, 应用XRD,SEM和PL光谱对该体系材料进行了表征.在Y2O3:Er3+纳米材料体系中, 观察和研究了Stokes及anti-Stokes PL谱强度与Er3+离子摩尔浓度变化的关系, 当Er3+离子浓度为2.0mol%时, anti-Stokes PL强度最强.粉末X
关键词:
氧化钇纳米晶
anti-Stokes PL
双光子吸收 相似文献
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Al2O3:Fe3+体系晶格局域结构的EPR理论研究 总被引:3,自引:1,他引:2
本文通过分析Al2O3∶Fe3+体系中Fe3+离子的EPR谱,研究Fe3+的局域晶体结构结果表明Al2O3∶Fe3+的局域结构存在各向异性膨胀.用拟合EPR谱的低对称参量D和(a-F)实验值的方法,求得两个三棱锥的棱与C3轴的夹角分别为θ1=46.54°和θ2=61.26°,相对于原Al2O3结构的畸变角分别是Δθ1=-1.1°±0.1°,Δθ2=-1.8°.两畸变角同时均小于0说明Al2O3∶Fe3+体系中含Fe3+离子的晶格主要产生沿C3轴的伸长畸变. 相似文献
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In this paper, we propose a system combining the pickup process using an active sensor and the display process using depth-priority integral imaging (DPII) system to display true three-dimensional (3D) objects within large depth through real and virtual image fields. The active sensor provides depth map and color images of 3D objects. Using captured depth map and original color images, elemental images are computationally synthesized and displayed optically in DPII system. Proposed system provides scaling of 3D scenes for true 3D object. To show the usefulness of proposed system, we carry out the experiment for true 3D objects of three character patterns and present the experimental results. 相似文献
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We argue that the large Jahn-Teller (JT) distortions in YVO3 and LaVO3 should suppress the quantum orbital fluctuation. The unusual magnetic properties can be well explained based on local density approximation + Hubbard U calculations using experimental structures, in terms of the JT orbital. The observed splitting of the spin-wave dispersions for YVO3 in a C-type antiferromagnetic state is attributed to the inequivalent VO2 layers in the crystal structure, instead of the "orbital-Peierls state." Alternative stacking of ab-plane exchange couplings produces the c-axis spin-wave splitting; thus, the spin system is highly three dimensional rather than quasi-one-dimensional. Similar splitting is also predicted for LaVO3, although it is weak. 相似文献