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331.
A computational study on the structural and electronic properties of a special class of artificial atoms, known as quantum dots, has been carried out. These are semiconductors with unique optical and electronic properties and have been widely used in various applications, such as bio-sensing, bio-imaging, and so on. We have considered quantum dots belonging to II–VI types of semiconductors, due to their wide band gap, possession of large exciton binding energies and unique optical and electronic properties. We have studied their applications as chemical ion sensors by beginning with the study of the ion sensing ability of (CdSe) n (n?=?3, 6, 9 which are in the size range of ~?0.24, 0.49, 0.74 nm, respectively) quantum dots for cations of the zinc triad, namely Zn2+, Cd2+, Hg2+, and various anions of biological and environmental importance, and studied the effect of increasing number of rings on their ion sensing ability. The various structural, electronic, and optical properties, their interaction energies, and charge transfer on interaction with metal ions and anions have been calculated and reported. Our studies indicate that the CdSe quantum dots can be employed as sensors for both divalent cations and anions, but they can sense cations better than anions. 相似文献
332.
Frank Ruthe Peter G. Jones Wolf‐W. du Mont Paola Deplano Maria L. Mercuri 《无机化学与普通化学杂志》2000,626(5):1105-1111
Oxidation of Triisopropylphosphane with Iodine: The Role of Dry or Moist Solvent i‐Pr3P ( 1 ) and iodine give i‐Pr3PI2 ( 2 ). In crystals obtained from CH2Cl2 solution, ion pairs [i‐Pr3PI+I–] of 2 exhibiting I…I interactions are linked by CH2Cl2 molecules. With a second equivalent of iodine, i‐Pr3PI+ I3– ( 3 ) is formed; the reaction of 2 with AgSbF6 provides i‐Pr3PI+SbF6– ( 6 ). The presence of moisture and air leads to the formation of i‐Pr3POH+ salts. Solid i‐Pr3POH+I– ( 4 ) exhibits P–O–H…I cation‐anion contacts, solid (i‐Pr3PO)2H+I3– ( 5 ) contains a centrosymmetric P=O…H…O=P‐bridged cation. Distinguishing i‐Pr3PI+ salts 2 , 3 from hydrolysis products 4 , 5 by 31P‐NMR in reaction mixtures is not trivial, because both kinds of cations exihibit similar 31P‐NMR shifts and both participate in interactions with their anions, and in equilibria with uncharged donors: rapid I+ transfer reactions and I…I soft‐soft interactions involving 1 , and rapid H+ transfer reactions and hydrogen bonds involving i‐Pr3P=O ( 7 ). 相似文献
333.
Using the Nikiforov-Uvarov (NU) method, pseudospin and spin symmetric solutions of the Dirac equation for the scalar and vector Hulthén potentials with the Yukawa-type tensor potential are obtained for an arbitrary spin-orbit coupling quantum number κ. We deduce the energy eigenvalue equations and corresponding upper- and lower-spinor wave functions in both the pseudospin and spin symmetry cases. Numerical results of the energy eigenvalue equations and the upper- and lower-spinor wave functions are presented to show the effects of the external potential and particle mass parameters as well as pseudospin and spin symmetric constants on the bound-state energies and wave functions in the absence and presence of the tensor interaction. 相似文献
334.
依据液相色谱中溶质计量置换保留模型及线性参数 log I(与 1mol溶质对固定相的亲和势大小有关的常数 ) ,通过作图得知非极性和极性小分子溶质及生物大分子的 log I与绝对温度的倒数 1/T,以及小分子溶质的log I与其在正辛醇 -水中分配系数的对数 log Po/ w呈线性关系 ,从两方面进一步证明了 log I具有热力学平衡常数的性质。基于小分子溶质、生物大分子的 log I和分配系数大小的差别 ,对两者在反相液相色谱中的保留对柱长的依赖关系给予了定量的说明 相似文献
335.
Dirk Sewing Wolf-Walther du Mont Siegfried Pohl
Wolfgang Saak Dieter Lenoir 《无机化学与普通化学杂志》1998,624(8):1363-1368
Diacyltellurides: Synthesis by Reactions of Acyl Chlorides with Bis(trialkylsilyl)tellurides. Structure Determinations of Di(1-adamantoyl)telluride and Adamantanecarbonic Anhydride Bis(isopropyldimethylsilyl)telluride ( 1 ) is prepared from tellurium with lithiumtriethylhydridoborate and chloro(isopropyl)dimethylsilane. From reactions of acylchlorides RCOCl with 1 , diacyltellurides (RCO)2Te (R = CH3- 2 , i-C3H7- 3 , i-C4H9- 4 , (CH3)3CH2-) 5 are isolated in pure state after removal of chloro(isopropyl)dimethylsilane. With succinic and glutaric dichlorides, 1 leads to impure cyclic diacyltellurides 6 (tellurosuccinic anhydride) and 7 (telluroglutaric anhydride). The reactions of bulky pivaloyl chloride and 1-adamantoyl chloride with 1 are too slow to be synthetically useful, but using bis(trimethylsilyl)telluride, dipivaloyltelluride 8 and di(1-adamantoyl)telluride 9 are straightforwardly available. 9 is accompanied by traces of 1-adamantanecarbonic anhydride 10 and by small amounts of di(1-adamantyl)ditelluride 11 . Constitutions of the new compounds 1 , 3–7 and 9 were confirmed by multinuclear NMR and mass spectroscopy. The structures of 9 and 10 were determined by X-ray crystallography. 相似文献
336.
L. -L. Andersson D. Rudolph E. K. Johansson D. A. Torres B. G. Carlsson I. Ragnarsson C. Andreoiu C. Baktash M. P. Carpenter R. J. Charity C. J. Chiara J. Ekman C. Fahlander C. Hoel O. L. Pechenaya W. Reviol R. du Rietz D. G. Sarantites D. Seweryniak L. G. Sobotka C. H. Yu S. Zhu 《The European Physical Journal A - Hadrons and Nuclei》2008,36(3):251-278
A largely extended experimental knowledge of the 61
29Cu32 nucleus has been obtained from three experiments. Excited states in 61Cu were produced via the fusion-evaporation reaction 28Si(36Ar, 3p)61Cu . In addition to the Ge array GAMMASPHERE, neutron and charged-particle detectors placed around the target position were
used for high-performance particle spectroscopy. The constructed level scheme includes more than 160 energy levels and 320
γ -ray transitions belonging to both normally deformed as well as superdeformed rotational structures. The multipolarities
have been determined for the γ -ray transitions and as a result spin-parity assignments are given for nearly all energy levels.
Experimental results in the normally deformed region are compared with predictions from large-scale shell model calculations.
The collective structures are compared with results from cranked Nilsson-Strutinsky calculations. The results reveal the need
to modify the standard Nilsson parameters in the mass A ∼ 60 region. 相似文献
337.
Dead cell and side leakage correction for a lead-scintillating fiber electromagnetic calorimeter
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Cheng Zhang Zu-Hao Li Zhi-Cheng Tang Suzan Basegmez du Pree Shao-Wen Zhang Xue-Qiang Wang Min Yang Guo-Ming Chen He-Sheng Chen 《中国物理C(英文版)》2016,40(9):096204-096204
The electromagnetic calorimeter(ECAL) of the Alpha Magnetic Spectrometer(AMS-02) is one of the key detectors for dark matter searches. It measures the energies of electrons, positrons and photons and seperates them from hadrons. Currently, there are 5 dead cells in the ECAL, which affect the reconstructed energy of 4.2%of total events in the ECAL acceptance. When an electromagnetic shower axis is close to the ECAL border, due to the side leakage, the reconstructed energy is affected as well. In this paper, methods for dead cells and side leakage corrections for the ECAL energy reconstruction are presented. For events with the shower axis crossing dead cells,applying dead cell correction improves the difference in the reconstructed energy from 12% to 1%, while for events near the ECAL border, with side leakage correction it is improved from 4% to 1%. 相似文献
338.
首次研究了疏水作用色谱 (HIC)中芳香醇同系物在不同种类盐流动相中的保留行为。以计量置换保留模型中的参数Z分析了HIC中小分子与生物大分子保留行为的差别 ,以及不同流动相组成对两种类型溶质的洗脱范围及洗脱能力的影响。与反相色谱相似 ,芳香醇在HIC中的保留仍存在同系物规律。比较了小分子和生物大分子在不同盐溶液中的Z值变化 ,表明流动相中的盐仅改变小分子与固定相的水合程度 ,而对生物大分子 ,除改变其和固定相水合程度外 ,还会影响生物大分子与固定相接触区的分子构象 相似文献
339.
We investigate the exact solution of the Dirac equation for the Mie-type potentials under the conditions of pseudospin and spin symmetry limits. The bound state energy equations and the corresponding two-component spinor wave functions of the Dirac particles for the Mie-type potentials with pseudospin and spin symmetry are obtained. We use the asymptotic iteration method in the calculations. Closed forms of the energy eigenvalues are obtained for any spin-orbit coupling term κ. We also investigate the energy eigenvalues of the Dirac particles for the well-known Kratzer-Fues and modified Kratzer potentials which are Mie-type potentials. 相似文献
340.
F.C. Ragel P. de V. du Plessis A.M. Strydom 《Journal of Physics and Chemistry of Solids》2010,71(12):1694-1701
The solid solution (Ce1−xLax)PtGa has been studied through X-ray diffraction, magnetization (σ(B)), magnetic susceptibility (χ(T)), electrical resistivity (ρ(T)), magnetoresistivity (MR) and heat capacity (CP(T)) measurements. The Néel temperature (TN=3.3 K) for CePtGa is lowered upon La substitution as observed from χ(T) and ρ(T) measurements. The Kondo temperature TK as calculated from MR measurements is comparable to TN and also decreases with La substitution. The volume dependence of TK is in accordance with the compressible Kondo lattice model and a Doniach diagram of the results is presented. CP(T) measurements are presented for CePtGa, Ce0.2La0.8PtGa and LaPtGa and the results are discussed in terms of the electronic and magnetic properties. Other features of interest are anomalies in ρ(T) and CP(T) due to crystalline electric field effects and metamagnetism as observed in σ(B) studies for samples with 0≤x≤ 0.3. 相似文献