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481.
In this study, we have investigated the high-pressure structural phase transition of alkaline earth's chalcogenides within the framework of three-body potentials. We are considering short-range repulsive interactions up to the second nearest neighbors. The structural phase transition from the low-pressure NaCl (B1) to the high-pressure CsCl (B2) structure is estimated by Gibbs free energy calculations. The results are satisfactory and in agreement with the available experimental and other theoretical results. 相似文献
482.
Vikas Kumar Alessio Gambetta Cristian Manzoni Roberta Ramponi Giulio Cerullo Marco Marangoni 《Pramana》2010,75(6):1129-1134
We demonstrate a new approach to CARS spectroscopy by efficiently synthesizing synchronized narrow-bandwidth (less than 10
cm−1) pump and Stokes pulses (frequency difference continuously tunable upto ≈3000 cm−1) based on spectral compression together with second harmonic generation (in periodically-poled nonlinear crystals) of femtosecond
pulses emitted by a single compact Er-fibre oscillator. For a far better signal to non-resonant background contrast, interferometric
CARS (I-CARS) is demonstrated and CARS signal enhancement upto three orders of magnitude is achieved by constructive interference
with an auxiliary local oscillator at anti-Stokes field, also synthesized by spectral compression of pulses emitted from the
same fibre oscillator. 相似文献
483.
S. V. Thakare A. G. C. Nair S. Chakrabarty B. S. Tomar 《Journal of Radioanalytical and Nuclear Chemistry》1999,242(2):537-539
An alternative reaction route for the production of111In from rhodium target bombarded with a12C beam has been developed. Sulfate fusion was adapted for dissolution of the irradiated rhodium metal target. Indium was coprecipitated
with La(OH)3 and purified by solvent extraction of the InBr3 complex into di-isopropyl ether and back extraction in 6M HCl. The chemical yield of the separation, determined using105Rh as tracer, was found to be above 90%. The radionuclidic purity of the separated111In satisfies the requirement prescribed for radiopharmaceutical preparations. The radioactivity yield achieved using this
route was about 0.2 MBq/μAh. 相似文献
484.
R. S. Tomar Prakash Bhartia 《International Journal of Infrared and Millimeter Waves》1985,6(9):807-829
Effects of manufacturing tolerances in the dimensions and parameters of suspended and inverted microstrip lines on the electrical performance of these lines have been studied through sensitivity analysis. The closed-form expressions recently given by Pramanick and Bhartia for the analysis of these lines have been used to derive the mathematical expressions for various sensitivities and the dependence of sensitivities on the aspect ratios and on the substrate dielectric constant has been depicted graphically. Generally speaking, the effects of tolerances are seen to be reflected much more sharply in the sensitivities of the characteristic impedance than in those of the effective dielectric constant. Many other useful inferences are also drawn from the sensitivity graphs. The conclusions are presented in tabular form, so as to be of direct help to the user. 相似文献
485.
C. S. Dileep Poonam Jagasia S. K. Das Prem Singh Dhami S. C. Tripathi P. M. Gandhi B. S. Tomar 《Journal of Radioanalytical and Nuclear Chemistry》2013,296(1):105-110
This work focuses on the polymorphic nature of the UO3 and UO3–H2O system, which are important materials associated with the nuclear fuel cycle. The UO3–water system is complex and has not been fully characterized, even though these species are key fuel cycle materials. Powder X-ray diffraction, and Raman and fluorescence spectroscopies were used to characterize both the several polymorphic forms of UO3 and the certain UO3-hydrolysis products for the purpose of developing predictive capabilities and estimating process history; for example, polymorphic phases of unknown origin. Specifically, we have investigated three industrially relevant production pathways of UO3 and discovered a previously unknown low temperature route to the production of β-UO3. Several phases of UO3, its hydrolysis products, and key starting materials were synthesized and characterized as pure materials to establish optical spectroscopic signatures for these compounds for forensic analysis. 相似文献
486.
Vaidya Vikas V. Menon Sasikumar N. Singh Ganesh R. Kekare Maharudra B. Choukekar Milind P. 《平面色谱法杂志一现代薄层色谱法》2007,20(2):145-147
JPC – Journal of Planar Chromatography – Modern TLC - An HPTLC method for simultaneous determination of clotrimazole and tinidazole in a pharmaceutical formulation has been developed... 相似文献
487.
S. B. Manohar A. Goswami B. S. Tomar 《Journal of Radioanalytical and Nuclear Chemistry》1996,203(2):331-351
Present status of work on charge and mass distribution in medium energy fission of compound nuclei produced using various target projectile combinations is reviewed. Systematics of charge distribution parameters and their dependence on excitation energy of the fissioning nucleus is presented. Variation of mass distribution with excitation energy and mass and charge of the fissioning nucleus is discussed. Qualitative explanation of the data has been sought in terms of existing theories of fission. The importance of charge and mass distribution studies in identifying the different reaction mechanisms in heavy ion induced reaction is highlighted.This article is dedicated to the memory of our beloved friend and colleague Dr. Tarun Datta who passed away on April 2, 1995. 相似文献
488.
Cochran FV Wu SP Wang W Nanda V Saven JG Therien MJ DeGrado WF 《Journal of the American Chemical Society》2005,127(5):1346-1347
We report the complete de novo design of a four-helix bundle protein that selectively binds the nonbiological DPP-Fe(III) metalloporphyrin cofactor (DPP-Fe(III) = 5, 15-Di[(4-carboxymethyleneoxy)phenyl]porphinato iron(III)). A tetrameric, D2-symmetric backbone scaffold was constructed to encapsulate two DPP-Fe(III) units through bis(His) coordination. The complete sequence was determined with the aid of the statistical computational design algorithm SCADS. The 34-residue peptide was chemically synthesized. UV-vis and CD spectroscopy, size-exclusion chromatography, and analytical ultracentrifugation indicated the peptide undergoes a transition from a predominantly random coil monomer to an alpha-helical tetramer upon binding DPP-Fe(III). EPR spectroscopy studies indicated the axial imidazole ligands were oriented in a perpendicular fashion, as defined by second-shell interactions that were included in the design. The 1-D 1H NMR spectrum of the assembled protein displayed features of a well-packed interior. The assembled protein possessed functional redox properties different from those of structurally similar systems containing the heme cofactor. The designed peptide demonstrated remarkable cofactor selectivity with a significantly weaker binding affinity for the natural heme cofactor. These findings open a path for the selective incorporation of more elaborate cofactors into designed scaffolds for constructing molecularly well-defined nanoscale materials. 相似文献
489.
Shyamprasad Karagadde Anirban Bhattacharya Gaurav Tomar Pradip Dutta 《Journal of computational physics》2012,231(10):3987-4000
A coupled methodology for simulating the simultaneous growth and motion of equiaxed dendrites in solidifying melts is presented. The model uses the volume-averaging principles and combines the features of the enthalpy method for modeling growth, immersed boundary method for handling the rigid solid–liquid interfaces, and the volume of fluid method for tracking the advection of the dendrite. The algorithm also performs explicit–implicit coupling between the techniques used. A two-dimensional framework with incompressible and Newtonian fluid is considered. Validation with available literature is performed and dendrite growth in the presence of rotational and buoyancy driven flow fields is studied. It is seen that the flow fields significantly alter the position and morphology of the dendrites. 相似文献
490.
In this paper the effect of temperature on the mechanoluminescence of Au doped phosphors of(Zn,Cd)S is described.It is found that the ML disappears beyond a particular temperature.The temperature dependence of ML intensity follows the relation I =I_T~O(1-TIT_C)~n,where I_T~O is a constant,n is the slop of log I_T versus log(1- TIT_C) plot which lies between 0.9 and 1.10,T_C is the temperature at which ML disappear.It is found that the ML intensity in(Zn,Cd)S:Au disappear at 600 K. 相似文献