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排序方式: 共有1136条查询结果,搜索用时 15 毫秒
51.
T.R. Rautray V. Vijayan M. Sudarshan S. Panigrahi 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(17):2878-2883
Particle induced X-ray emission, particle induced γ-ray emission studies has been carried out to analyse normal and carcinoma tissues and blood samples of gallbladder of both sexes and seventeen trace elements namely Na, Mg, Al, K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br and Pb were estimated in the tissue and blood samples. In the present study, concentration of Zn in the carcinoma gallbladder tissue is less than that of the normal gallbladder tissue. Tobacco habit could be one of the important factors to decrease the elemental concentrations in blood and tissue samples. 相似文献
52.
构造了一类新的周期为素数 的六次剩余序列,利用有限域和差集理论给出了该序列在周期为素数 情形下的迹函数表示.新序列的线性复杂度为 ,优于Hall六次剩余序列在相同条件下的线性复杂度. 相似文献
53.
The Callovian-Oxfordian carbonate reservoirs are the most important hydrocarbon reservoir in the Samandepe gas field,Amu Darya basin,Turkmenistan.Based on the analysis of Fe,Mn and Sr trace elements,and carbon,oxygen and strontium isotopes,the genesis and evolutionary characteristics of the carbonate reservoirs were studied,and the conclusions were follows:1) Sustained transgressive-regressive cycles played an important role during Callovian-Oxfordian.The reservoir of reef-bank facies was well developed in the period of transgression,while the regional dense cap rocks developed in the period of regression;2) The 87 Sr/86 Sr ratio measured from rudist shells yields an age of 157.2 Ma according to the global strontium isotope curve;3) As diagenetic intensity increased,δ 13 C changed little,and δ 18 O showed strong negative deviation but was still limited to the range of Late Jurassic seawater.High Fe and Sr contents,and low Mn content,and the evolutionary trend of δ 13 C and δ 18 O all indicate that diagenesis occurred in a relatively confined environment,where the fluids were relatively reducing and contained hot brine.The stage of diagenesis reached is mesodiagenesis,which is very favorable for preservation of primary pores in carbonates;4) Strong dissolution of reef limestones,burial dolomitization and hydrothermal calcite precipitation were all the results of the interaction between the 87 Sr-rich diagenetic fluid and rocks;5) The analysis results of isotopes,fluid inclusions and vitrinite reflectance show that the diagenetic fluid was compaction-released water that originated from the deep,coal-bearing clastic strata. 相似文献
54.
微波消解-电感耦合等离子体质谱法同时测定化妆品中五种微量元素 总被引:2,自引:0,他引:2
本文以Sc、Ge、In、Re内标校正体系,采用微波消解-电感耦合等离子体质谱法(ICP-MS)对化妆品中As、Pb、Hg、Cd和Cr五种微量元素进行同时测定,通过对三种化妆品的加标回收试验,建立了化妆品中As、Pb、Hg、Cd和Cr五种微量元素含量的ICP-MS分析方法,Hg所采用线性范围为0~10ng/ml,其它元素所采用线性范围为0~500ng/ml,各元素校正方程的线性相关系数均大于0.9996,各元素检出限均小于0.1ng/mL、测定五种元素的相对标准偏差均小于10%,各元素的加标回收率在84.1%~107.9%。实验表明:该法操作简单、快速,灵敏度高,重现性好,而且能够对五种微量元素进行同时测定,大大提高了检测效率。 相似文献
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57.
《Intermetallics》2014
Ni segregation in the interfacial (Cu,Ni)6Sn5 intermetallic layer of Sn-0.7Cu-0.05Ni/Cu BGA solder joints was investigated by using synchrotron micro X-ray fluorescence (XRF) analysis and synchrotron X-ray diffraction (XRD). Compared to Sn-0.7Cu/Cu BGA joints, Ni containing solder show suppressed Cu3Sn growth in both reflow and annealed conditions. In as-reflowed Sn-0.7Cu-0.05Ni/Cu BGA joints, Ni was relatively homogenously distributed within interfacial (Cu,Ni)6Sn5. During subsequent annealing, the diffusion of Ni in Cu6Sn5 was limited and it remained concentrated adjacent the Cu substrate where it contributes to the suppression of Cu3Sn formation at the interface between the Cu substrate and Cu6Sn5 intermetallics. 相似文献
58.
Infant formula developed by manufacturers requires a rigorous control of composition, particularly those elements added routinely in an attempt to mimic the mineral composition of human milk. A total of 97 different types of powdered infant formulae (preterm, adapted starter, adapted follow-up, toddler, specialised and soy-based formulae) commercially available in Spain were studied. It is noteworthy great differences in mineral (Ca, P, Mg) and trace element (Zn, Fe, Cu, Mn) contents found between analysed and listed in label information. The development of a fast, simple and direct slurry method for the determination of these essential micronutrients in infant formula by inductively coupled plasma optical emission spectrometry (ICP OES) and flame atomic absorption spectrometry (FAAS) was performed in order to help in quality control tasks. Infant formula samples were solubilised using different amounts of several different solvents. An addition of 250 μL of a solution 10% tetramethylammonium hydroxide and 25% ammonium hydroxide were required for the accurate quantification of Ca and P, Mg, Zn, Fe, Cu and Mn, respectively. The standard reference material 1549 non-fat milk powder was solubilised to compare the validity of assayed methodology following slurry nebulisation and traditional microwave-assisted acid digestion method. Good agreement of the analytical results by both ICP OES and FAAS, with the certified values was obtained. Method performance parameters (accuracy, precision and methodological detection limits) were determined for studied elements to check the quality and usefulness of the optimised slurry method. The analytical procedure was applied successfully to the analysis of a representative group of infant formulae. Levels of analysed elements were graphically represented, showing an acceptable comparability between slurry and acid-mineralisation method set by linear correlation coefficients and slopes close to the unit. The described simple and slurry method is appropriate, as an attractive alternative, for routine control analysis of added essential elements in infant formulae regardless of predominant protein type used in manufacture. 相似文献
59.
Kyunghun Jung Yuta Yamamoto Shuichi Hasegawa 《Journal of Nuclear Science and Technology》2017,54(11):1261-1266
Excess micromotion of trapped calcium ions was detected and compensated in our linear Paul trap apparatus for trace isotope analysis. The micromotion was detected by Charge-coupled device (CCD). camera and radio frequency (rf) correlation method. We found that 230 and 2280 V of compensation voltages were needed for x- and y-axis compensation in our apparatus, respectively. The z-axis micromotion was confirmed by the experiment and its cause was investigated by finding a shape of z-axis confinement field. The confinement field was indeed distorted in our apparatus and it gave rise to the trapped ion to shift from potential center. And the micromotion of r-direction was transferred to the z-axis by the distorted confinement field. The z-axis micromotion was suppressed by increasing cap voltage of trap. 相似文献
60.
Carolyn M. Nyberg Jeffrey S. Thompson Ye Zhuang John H. Pavlish Lynn Brickett Sara Pletcher 《Fuel Processing Technology》2009
During the past several years, and particularly since the Clean Air Mercury Rule (CAMR) was promulgated in June of 2005, the electric utility industry, product vendors, and the research community have been working diligently to develop and test Hg control strategies for a variety of coal types and plant configurations. Some of these strategies include sorbent injection and chemical additives designed to increase mercury capture efficiency in particulate control devices. These strategies have the potential to impact the fate of other inorganic hazardous air pollutants (HAPs), which typically include As, Be, Cd, Cr, Co, Mn, Ni, Pb, Se, and Sb. To evaluate this impact, flue gas samples using EPA Method 29, along with representative coal and ash samples, were collected during recent pilot-scale and field test projects that were evaluating Hg control technologies. These test programs included a range of fuel types with varying trace element concentrations, along with different combustion systems and particulate control devices. The results show that the majority of the trace element HAPs are associated with the particulate matter in the flue gas, except for Se. However, for five of the six projects, Se partitioning was shifted to the particulate phase and total emissions reduced when Hg control technologies were applied. 相似文献