火焰原子吸收法测定高含量硒中碲

硒化合物在电子、玻璃等工业部门用途广泛，对高含量硒中碲的测定通常是用分光光度比色法或极谱法。本文详细研究了火焰原子吸收光谱法在这领域中的应用。使用本方法不必从硒化物试样中分离碲。在０．６—１．２ｍｏｌ／ＬＨＣｌ介质中测定碲时，检出限０．０８μｇ／ｍＬ，特证浓度０．１５μｇ／ｍＬ１％，线性范围１—２０μｇ／ｍＬ。相关系数０．９９９８。     

连续氢化法电感耦合等离子体发射光谱同时测定生物样品…

本文叙述用氢化法电感耦合等离子体发射光谱同时测定生物样品中痕量硒，砷，锡，锑的方法。比较了浓度为２．８８ｍｏｌ／Ｌ，４．８ｍｏｌ／Ｌ和６．０ｍｏｌ／Ｌ的ＨＣｌ对Ｓｅ，Ａｓ，Ｓｎ，Ｓｂ，Ｈｇ和Ｇｅ谱线强度的影响，也比较了ＮａＢＨ４溶液中ＶＣ对测定Ｓｅ，Ａｓ，Ｓｂ，Ｓｎ，Ｈｇ和Ｇｅ的影响。在４．８ｍｏｌ／Ｌ ＨＣｌ浓度下，在１％ＮａＢＨ４溶液中加０．５％ＶＣ，ＨＹ－ＩＣＰ－ＡＥＳ的检出限是：Ｓｅ ０．     

导数光谱法同时测定甲硝唑和维生素B6的研究

本建立了以０．１ｍｏｌ／ＬＨＣｌ为介质，采用三阶导数光谱法，同时测定甲硝唑和维生素Ｂ６的新方法，方法检测限为０．８１μｇ／ｍＬ甲硝唑和０．１６μｇ／ｍＬ维生素Ｂ６，二测定的线性范围均为１．６－２２．４μｇ／ｍＬ，直接用于复方甲硝唑片剂中甲硝唑和维生素Ｂ６的测定，两种生物的测定变异系数分别小于２．２６和２．６０％，回收率分别为９３－１０２％和９９－１０１％．     

平台石墨炉原子吸收法测定高温镍基合金中痕量碲

用镍作基体改进剂，碲的灵敏度提高的约２倍，灰化温度提高４００℃，抗干扰能力明显增强，不需要分离样品基体，采用平台石墨炉即可同温镍基金中痕量磅。方法检出限为０．０４１μｇ／ｇ，样品中碲含量为０．５μｇ／ｇ时，相对标准偏差为３－６％，回收率在９０－９９％之间，方法简单快速。     

双波长倍增差示法测定双嘧啶片中磺胺嘧啶和甲氧苄啶的含量

本论述了双波长倍增差示法同时测定了双嘧啶片中磺胺嘧啶（ＳＤ）和甲氧苄啶（ＴＭＰ）的含量，本法是基于测定标准溶液ＳＤ（８～１４）×１０＾－６ｇ／ｍＬ，ＴＭＰ（１～２）×１０＾－６ｇ／ｍＬ，和样品溶液在２４２．５ｎｍ和２２８．０ｎｍ处的吸收度。ＳＤ和ＴＭＰ的平均回收率与ＲＳＤ分别为１００．６０％，０．３３％，和９８．２７％，１．５８（ｎ＝２０）。本法简便快捷，结果满意。     

流动注射在线萃取—火焰原子吸收光谱法测定明胶中的微量Fe和Cu

本文采用氧化水解制样及流动注射在线取火焰原子吸收光谱法，测定明胶中微量Ｆｅ和Ｃｕ，解决了水解法制样测定结果偏低和不能直接测定低含量样品的问题。本文法测定Ｆｅ和Ｃｕ的灵敏度分别提高了１４．５倍和１７．６倍，分析速度达３６次／ｈ，Ｆｅ和Ｃｕ的回收率分别在９０．８－１１０．５％和７．５－１０７．０％之间，测定精密度分别为４．５３％和４．２６％。     

火焰原子吸收法同时测定地质样品中金和银

二氯化锡还原，二氯化汞共沉淀，火焰原子吸收法同时测定地质样品中金和银。对于原矿和尾矿样品，金含量为５．１５μｇ／ｇ，４．４５μｇ／ｇ和０．５４μｇ／ｇ时，相对标准偏差分别为６．２％，３．４％和４．１％。银含量为９．７８μｇ／ｇ和１．２２μｇ／ｇ时，相对标准偏差分别为４．４％，３．５％和１２．５％。金的分析结果与参考值基本一致。金和银的回收率分别为８８－１０２％和８５－１００％。方法具有干扰小，分离     

磁场效应下分子发光行为的研究：Ⅲ.痕量蒽,北同时MFE共振同步…

本文建立了痕量蒽、北的同时磁场效应（ＭＦＥ）共振同步荧光分析方法，该法能有效地抑制同步描述过程中散射光的波动而使在低试样浓度下测定蒽、北的灵敏度提高。蒽和北的检测限分别为０．１４和０．０２７ｎｇ／ｍｌ。相对标准偏差不大于６％。     

流动注射在线萃取－火焰原子吸收光谱法测定明胶中的微量Fe和Cu

本文采用氧化水解制样及流动注射在线萃取火焰原子吸收光谱法，测定明胶中微量Ｆｅ和Ｃｕ，解决了水解法制样测定结果偏低和不能直接测定低含量样品的问题。本方法测定Ｆｅ和Ｃｕ的灵敏度分别提高了１４．５倍和１７．６倍，分析速度达３６次／ｈ，Ｆｅ和Ｃｕ的回收率分别在９０．８－１１０．５％和８７．５～１０７．０％之间，测定精密度分别为４．５３％和４．２６％。     

流动注射氢化物发生原子吸收法测定血液中硒

采用流动注射分析与氢化物发生原子吸收相结合的方法测定了血液中痕量硒。采用ＨＮＯ３－ＨＣｌＯ４体系溶解样品，取样量少，样品处理简单，快速。本法检出限为０．０６μｇ／Ｌ＾－１（３σ），进样频率为１２０－１５０样次／小时。讨论了砷对硒测定时的干扰及其排除方法，用该法测定了３００个正常人全血和７５个血清样品，其硒含量范围分别为０．０５６－０．１１８μｇｍ１＾－１和０．０４０－０．０７６μｇｍ１＾－１，回收     

碲、硒碲合金纳米线的可控合成

"采用一种新的化学溶液法合成了具有不同形貌的碲、硒碲合金纳米线．用十二烷基苯磺酸钠作为表面活性剂实现了对纳米线的可控合成,通过控制反应过程可以弯曲状、"V"字型的硒碲纳米线,利用XRD、TEM以及HRTEM对纳米线的形貌结构特征进行表征;以实验结果为依据讨论了纳米线的生长机理．"     

Evidence for insulator–metal transition in amorphous chalcogenide Se–Ge–Te films

The temperature dependence of the dc conductivity and thermoelectric power was determined for five different amorphous chalcogenide Se–Ge–Te films, with Ge?=?3.0–22?at.%, Se?=?0–97?at.% and Te?=?0–97?at.%. The films were prepared by thermal evaporation of GeSe₄, GeTe₄ and GeSe₂Te₂ quenched bulk materials. Values of the activation energy calculated from the temperature dependence of both electrical conductivity and thermoelectric power showed a decrease with increasing Ge content in the Se–Ge films as well as with replacement of Te for Se in the Se–Ge–Te films. The results showed an Anderson transition, with the conductivity showing insulating behaviour on the Ge–Se side to metallic behaviour at the binary composition Ge–Te. The radius of localization was obtained for the different compositions investigated. The wave function associated with the charge carriers at the composition Ge_3.3Te_96.7 is non-localized. A minimum metallic conductivity of 237?±?5?(Ω?cm)^?1 was found.     

Synthesis,Spectroscopic Characterization,Thermogravimetric and Biological Activity Evaluation of Te(Ⅳ),Se(Ⅳ),V(Ⅲ),Nb(Ⅴ),Ta(Ⅴ)Complexes With Indole-3-Acetic Acid Plant Hormone Ligand

Te(Ⅳ), Se(Ⅳ), V(Ⅲ), Nb(Ⅴ) and Ta(Ⅴ) complexes of indole-3-acetic acid (IAAH) ligand were synthesized, characterized by elemental analysis and various spectroscopic techniques like, IR, 1H-NMR, X-ray powder diffraction, UV-Visible, thermogravimetry analysis, magnetic measurements, molar conductance and surface morphology using SEM. All the synthesized complexes of IAAH ligand have 1∶2 stoichiometry of the types [Te(IAA)₂(NH₃)₂]·2Cl (Ⅰ), [Se(IAA)₂(NH₃)₂]·2Cl (Ⅱ), [V(IAA)₂(NH₃)(Cl)] (Ⅲ), [Nb(IAA)₂(Cl)₃] (Ⅳ), and [Ta(IAA)₂(Cl)₃] (Ⅴ). Spectral analysis indicates octahedral geometry for the Te(Ⅳ), Se(Ⅳ) and V(Ⅲ) complexes, whereas both Nb(Ⅴ) and Ta(Ⅴ) have a seven-coordination. The bonding sites are the oxygen atoms of carboxylate group for the deprotonated indole-3-acetic acid (IAA) ligand. The thermogravimetry analysis studies gave evidence for the presence of other coordinated molecules (Cl or NH₃) in the composition of IAA complexes, which were further supported by IR and micro analytical measurements. The higher molar conductance data of tellurium and selenium (Ⅳ) complexes reveal that these chelates are electrolytes, while low conductivity values for the vanadium(Ⅲ), niobium and tantalum(Ⅴ) chelates indicated a non-electrolytes. To test the antibacterial property of the five complexes in this study, four bacterial strains Klebsiella (G-), Escherichia coli (G-), Staphylococcus aureus (G+) and Staphylococcus epidermidis (G+) were used in the investigation. The effects of the five complexes in the cytotoxicity of Caco-2 and Mcf-7 human cancer cell lines were studied Neutral red uptake assay for the estimation of cell viability/cytotoxicity protocol.     

Dimers of heavy <Emphasis Type="Italic">p</Emphasis>-elements of groups IV–VI: Electronic,vibrational, and magnetic properties

Equilibrium lengths and binding energies, vibrational frequencies, width of the HOMO–LUMO gap, and the magnetic anisotropy energies for one- and two-component dimers of heavy p elements of Groups IV (Sn, Pb), V (Sb, Bi), and VI (Se, Te) with a pronounced relativistic effect have been calculated with the use of the formalism of the density functional theory. It has been shown that it is necessary to take into account the spin–orbit coupling, which significantly affects the energy parameters of clusters. The analysis of the data obtained has revealed that the Pb–Te, Pb–Se, Sn–Te, and Sn–Se dimers have the widest gap at the Fermi level and the lowest reactivity. The magnetic anisotropy energy has been calculated for all single- and doublecomponent dimers and the direction of the easy magnetization axis has been determined.     

The absorption spectra of single selenium and tellurium chains in dielectric matrix channels

The absorption spectra are reported for single Se and Te chains stabilized in the regular system of parallel channels of mordenite dielectric matrix. A conclusion is made that the Se(Te) chain located in the mordenite channel has no D₃ symmetry as the dihedral angle of the chain varies randomly. A correlation is found between absorption spectra of the Se(Te) chain and amorphous Se(Te).     

Nuclear quadrupole interaction at Te125 in monoclinic selenium

The quadrupole splitting (QS) at Te¹²⁵ in monoclinic Se is measured to be 11.33 ± 0.05 mm/sec. This interaction is attributed to a Te site covalently bonded to two Se near neighbors in the ring geometry. The isomer-shift (IS) and (QS) in monoclinic Se are found larger than in trigonal Se. These results are suggestive of a structurally dissimilar SeTeSe molecular unit in mixed rings and helical chains.     

Robust surface state of intrinsic topological insulator Bi2Te2Se thin films: a first-principles study

Bi(2)Te(2)Se, a ternary tetradymite compound, has recently been identified to be a three-dimensional topological insulator. In this paper, we theoretically study the electronic structures of bulk and thin films of Bi(2)Te(2)Se employing spin-orbit coupling (SOC) self-consistently with density-functional theory. It is found that SOC plays an important role in determining the electronic properties of Bi(2)Te(2)Se. A finite bandgap opens up in the surface states of Bi(2)Te(2)Se thin films due to the hybridization of the top and bottom surface states of films. The intrinsic Bi(2)Te(2)Se thin films of three or more quintuple layers exhibit a robust topological nature of electronic structure with the Fermi energy intersecting the Dirac cone of the surface states only once between time-reversal-invariant momenta. These characteristics of Bi(2)Te(2)Se are similar to the topological behavior of Bi(2)Te(3), promising a variety of potential applications in nanoelectronics and spintronics.     

Scanning tunneling microscopy on iron-chalcogenide superconductor Fe(Se, Te) single crystal

We have investigated the iron-chalcogenide superconductor Fe(Se, Te) using a low-temperature scanning tunneling microscopy/spectroscopy (STM/STS) technique. STM topography at 4.9 K shows clear regular square arrangements of spots with the lattice spacing ～0.37 nm, from which what we observe are attributed to Se or Te atomic plane. In the topography, brighter and darker atomic spots are randomly distributed, which are most probably due to Te and Se atoms, respectively. For the FeTe compound, the topography exhibits clusters of the bright spots probably arising from separated iron atoms distributing over several Te lattice sites. The STS measurements clarify the existence of the large-size gap with 2Δ = 0.4–0.6 eV.