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151.
Thin films of SnSb2S4 have been prepared on glass substrate by using thermal evaporation techniques. The films were annealed in argon gas at low pressure in sealed glass ampoules at 85 °C, 150 °C, 275 °C and 325 °C. XRD of the films reveal that the low temperature annealed films are poly crystalline while the as deposited films and high annealed films are in amorphous states. There is no adequate variation in the photoconductivity response of the amorphous and crystalline phases. The transmittance of the films is low and having no transmittance below 740 nm. The band gap calculated by ellipsometry technique is in the range of 1.82–3.1 eV. The films have n-type conductivity but the film annealed at 325 °C show p-type conductivity. 相似文献
152.
The characterization and accurate determination of the chloride content in cement/concrete is very important for the assessment of the durability and safety of a concrete structure. The available analytical techniques are relatively expensive and time consuming. In this study, a laser-induced breakdown spectroscopy (LIBS) system was used for determination of elemental composition in three different types of cement samples. The plasma was generated by focusing a pulsed Nd: YAG laser at 1064 nm on the cement samples. The concentrations of different elements of significance for structural stability in cement samples were determined. The evaluation of the potential and the capabilities of LIBS as a rapid tool for characterization of cement samples is discussed. The optimum LIBS setup and experimental conditions to detect and measure chloride in building materials are reported. The LIBS results were compared with the results obtained using a standard analytical technique such as inductively coupled plasma emission spectroscopy (ICP–ES). The limits of detection were determined, and calibration curves were measured. The results of this investigation indicate the reliability of LIBS to characterize different cement samples and to assess the chloride content in these cements. 相似文献
153.
S. Decoster C. J. Glover B. Johannessen R. Giulian D. J. Sprouster P. Kluth L. L. Araujo Z. S. Hussain C. Schnohr H. Salama F. Kremer K. Temst A. Vantomme M. C. Ridgway 《Journal of synchrotron radiation》2013,20(3):426-432
Lift‐off protocols for thin films for improved extended X‐ray absorption fine structure (EXAFS) measurements are presented. Using wet chemical etching of the substrate or the interlayer between the thin film and the substrate, stand‐alone high‐quality micrometer‐thin films are obtained. Protocols for the single‐crystalline semiconductors GeSi, InGaAs, InGaP, InP and GaAs, the amorphous semiconductors GaAs, GeSi and InP and the dielectric materials SiO2 and Si3N4 are presented. The removal of the substrate and the ability to stack the thin films yield benefits for EXAFS experiments in transmission as well as in fluorescence mode. Several cases are presented where this improved sample preparation procedure results in higher‐quality EXAFS data compared with conventional sample preparation methods. This lift‐off procedure can also be advantageous for other experimental techniques (e.g. small‐angle X‐ray scattering) that benefit from removing undesired contributions from the substrate. 相似文献
154.
Santanu Chakraborty D. Bhattacharjee Syed Arshad Hussain 《Applied Physics A: Materials Science & Processing》2013,111(4):1037-1043
In the present communication, we report the formation of organized nanoscale aggregates of a coumarin derivative 7 Hydroxy-N-Octadecyl Coumarin-3-Carboxamide (7HNO3C) at the air–water interface and in Langmuir–Blodgett (LB) films in the presence and absence of stearic acid (SA). A pressure-area isotherm reveals that the 7HNO3C form stable monolayer at the air–water interface. However, the stability can be improved by mixing it with a fatty acid stearic acid (SA). The miscibility study shows that the nature of interaction is strongly dependent on the mixing ratio and surface pressure. At a mole fraction of 0.4 of 7HNO3C in SA, the attractive and repulsive interaction between these two molecules balance each other forming a stable film with nanoscale aggregates. UV-Vis absorption spectroscopic studies reveal the nature of the aggregates in LB films. Scanning electron microscopy gives compelling visual evidence of formation of nanoscale aggregates in the mixed LB films. 相似文献
155.
156.
F. Hussain J. G. Körner J. Landgraf Salam Tawfiq 《Zeitschrift fur Physik C Particles and Fields》1995,69(1):655-662
We study the current-induced bottom baryon to charm baryon transitions in the Heavy Quark Symmetry limit asm q→∞. Our discussion involvess-wave tos-wave as well ass-wave top-wave transitions. Using a constituent quark model picture for the light diquark system with an underlyingSU(2N f)?O(3) symmetry and the heavy quark symmetry we arrive at a number of new predictions for the reduced form factors that describe these transitions. 相似文献
157.
In this note we obtain generalization of well known results of carbone and Conti, Sehgal and Singh and Tanimoto concerning
the existence of best approximation and simultaneous best approximation of continuous funcitons from the set up of a normed
space to the case of a Hausdorff locally convex space. 相似文献
158.
Faheem Hussain 《Physics letters. [Part B]》1991,260(3-4):359-364
A direct correspondence between supersymmetric models and a recently proposed field theory based on non-commutative geometry is established. 相似文献
159.
F. Hussain J. G. Körner J. Landgraf Salam Tawfiq 《Zeitschrift fur Physik C Particles and Fields》1996,69(4):655-662
We study the current-induced bottom baryon to charm baryon transitions in the Heavy Quark Symmetry limit as mq → ∞. Our discussion involves s-wave to s-wave as well as s-wave to p-wave transitions. Using a constituent quark model picture for the light diquark system with an underlying SU (2Nf) ? O(3) symmetry and the heavy quark symmetry we arrive at a number of new predictions for the reduced form factors that describe these transitions. 相似文献
160.
High-resolution angular-dependent X-ray photoemission (XPS) valence-band spectra from a copper single crystal with (001) orientation are presented and analyzed in terms of a direct-transition model of photoemission. This model includes the effects of photon momentum, spectrometer geometry, and, for very low angles of emission, refraction of electrons in leaving the surface, but neglects matrix-element variation. Theoretical calculations are found to be in good agreement with experiment for six distinct emission directions. For low (grazing) angles of emission, a sharpening of the d-band peak is observed that may be associated with surface-specific band-structure changes. 相似文献