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101.
Various empirical theories of ultrasonic velocity have been applied to three binary liquid mixtures, under pressures up to
200 MPa and their validity have been tested. A pressure dependent study of ultrasonic velocities has been made at 303.15 K.
The agreement between theory and experiment is found to be quite satisfactory. 相似文献
102.
Ibon Alkorta Fernando Blanco Pere M. Deyà José Elguero Carolina Estarellas Antonio Frontera David Quiñonero 《Theoretical chemistry accounts》2010,126(1-2):1-14
This review covers two aspects concerning cooperativity in multiple weak bonds: a summary of literature results and a theoretical study of a complete series of model complexes. All the 15 combination of five weak bonds were explored: hydrogen bonds, hydric bonds, dihydrogen bonds, halogen bonds and ion–π interactions. Since in several cases there were no examples reported, a systematic exploration has been carried out on simple models at the MP2/aug-cc-pVTZ level. The results thus obtained have been analyzed using the atoms in molecules methodology. 相似文献
103.
We have studied the analytic solutions for modified electron acoustic double layers and solitary waves in a four component plasma system viz. two electrons and two ions, one positive and the other negative. It has been shown that DL solution does not exist when the temperatures of the free and the trapped particles are considered to be same for all the free species. On the other hand, DL solutions are found to exist when the effects of the reflected electrons (hot) are considered. The velocity and thickness of the DL have been valculated. 相似文献
104.
Kinsuk Das Tarak Nath Mandal Somnath Roy Samik Gupta Anil Kumar Barik Partha Mitra Arnold L. Rheingold Susanta Kumar Kar 《Polyhedron》2010
The varying coordination modes of the title ligand, L [5-methyl-1-(pyridin-2-yl)-N′-[pyridin-2-ylmethylidene]pyrazole-3-carbohydrazide] towards the different metal centers is reported by preparation and characterization of Cu(II), Zn(II) and Cd(II) complexes, [Cu(L)NO3.H2O](NO3) (1) [Zn(L)2](ClO4)2·2DMF (2) and [Cd(L)(I)2] (3) respectively. In 1, the neutral ligand serves as tetradentate 4 N donor where both pyridine and pyrazole nitrogen atoms of pyridyl–pyrazole part are coordinatively active, leaving the carbonyl oxygen of the carbohydrazide part inactive. The same pyridine and pyrazole N atoms remain abstained from the coordination process towards the Zn(II) and Cd(II) metal centers. For 2 and 3 the ligand behaves as a tridentate NNO donor where the two nitrogen atoms come from azomethine, pyridine of pyridine-2-carbaldehyde parts and O from carbonyl oxygen atoms (carbohydrazide part). The complex 1 and 2 are distorted octahedral while complex 3 adopts distorted square pyramidal geometry. All the complexes are X-ray crystallographically characterized. 相似文献
105.
106.
Background
Triptolide is a diterpene triepoxide from the Chinese medicinal plant Tripterygium wilfordii Hook F., with known anti-inflammatory, immunosuppressive and anti-cancer properties. 相似文献107.
Daniel Lokshtanov Venkatesh Raman Saket Saurabh Somnath Sikdar 《Discrete Optimization》2011,8(1):97-109
We study the parameterized complexity of a directed analog of the Full Degree Spanning Tree problem where, given a digraph and a nonnegative integer , the goal is to construct a spanning out-tree of such that at least vertices in have the same out-degree as in . We show that this problem is W[1]-hard even on the class of directed acyclic graphs. In the dual version, called Reduced Degree Spanning Tree, one is required to construct a spanning out-tree such that at most vertices in have out-degrees that are different from that in . We show that this problem is fixed-parameter tractable and that it admits a problem kernel with at most vertices on strongly connected digraphs and vertices on general digraphs. We also give an algorithm for this problem on general digraphs with running time , where is the number of vertices in the input digraph. 相似文献
108.
S. Dey J. P. Gewali A. K. Jha L. Chhaigte Y. S. Jain 《Indian Journal of Physics》2011,85(8):1309-1330
High resolution spectroscopy of doped molecules in 4He nano-droplets and clusters gives a signature of superfluidity in microscopic system, termed as microscopic superfluidity. Ro-vibrational spectrum of 4HeN-M clusters is studied with the help of some important observations, revealed from experiments (viz., localised and orderly arrangement of 4He atoms, although, being free to move in the order of their locations; individual 4He atoms can not be tagged as normal/ superfluid, etc.) and other factors (e.g., consideration that the 4He atoms which happen to fall in the plane of rotation of a molecule, render a equipotential ring and thus, do not take part
in rotation; etc.) which effect the rotational and vibrational spectrum of the system. This helps us in successfully explaining the experimental
findings which state that the rotational spectrum of clusters have sharp peaks (indicating that the molecule rotates like
a free rotor) and moment of inertia and vibrational frequency shift have a non-trivial dependence on N. 相似文献
109.
S.C. Dey 《Journal of luminescence》2011,131(12):2707-424
The article reports a green chemical synthesis of colloidal ZnSe quantum dots at a moderate temperature. The prepared colloid sample is characterised by UV-vis absorption spectroscopy and transmission electron microscopy. UV-vis spectroscopy reveals as-expected blue-shift with strong absorption edge at 400 nm and micrographs show a non-uniform size distribution of ZnSe quantum dots in the range 1-4 nm. Further, photoluminescence and electroluminescence spectroscopies are carried out to study optical emission. Each of the spectroscopies reveals two emission peaks, indicating band-to-band transition and defect related transition. From the luminescence studies, it can be inferred that the recombination of electrons and holes resulting from interband transition causes violet emission and the recombination of a photon generated hole with a charged state of Zn-vacancy gives blue emission. Meanwhile electroluminescence study suggests the application of ZnSe quantum dots as an efficient light emitting device with the advantage of colour tuning (violet-blue-violet). 相似文献
110.
A. Delfino Jishnu Dey Mira Dey M. Malheiro 《The European Physical Journal C - Particles and Fields》2011,71(1):507-514
The models of translationally invariant infinite nuclear matter in the relativistic mean field models are very interesting and simple, since the nucleon can connect only to a constant vector and scalar meson field. Can one connect these to the complicated phase transitions of QCD? For an affirmative answer to this question, one must consider models where the coupling contstants to the scalar and vector fields depend on density in a nonlinear way, since as such the models are not explicitly chirally invariant. Once this is ensured, indeed one can derive a quark condensate indirectly from the energy density of nuclear matter which goes to zero at large density and temperature. The change to zero condensate indicates a smooth phase transition. 相似文献