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排序方式: 共有498条查询结果,搜索用时 125 毫秒
41.
Swarup Kumar Maji Anup Mondal Bibhutosh Adhikary Basudeb Karmakar 《Journal of Physics and Chemistry of Solids》2011,72(6):784-788
We report the formation of mesoporous zinc sulphide, composed by the fine network of nanoparticles, which was formed via a single precursor Zn(SOCCH3)2Lut2 complex. The complex was chemically synthesized using zinc carbonate basic, 3,5-lutidine and thioacetic acid, in air. The metal precursor complex was characterized using different conventional techniques. Thermogravimetric analysis (TGA) result indicates that the decomposition of the complex starts at 100 °C and continues up to 450 °C, finally yielding ZnS. ZnS nanocrystals were characterized by powder X-ray diffraction (XRD) technique, field emission scanning electron microscopy (FESEM), N2-sorption isotherm, UV-vis spectroscopy and photoluminescence (PL) spectroscopy. The grain diameter of nanocrystals was found to be 4-5 nm. The material followed Type-IV N2-sorption isotherm, which is the characteristic of mesoporous materials. The band gap energy, as obtained from optical measurements was around 3.8 eV. 相似文献
42.
In this study, in situ control growth of bismuth nanoparticles (Bi0 NPs) was demonstrated in bismuth-based glass dielectrics under an electron beam (EB) irradiation at room temperature. The
effects of EB irradiation were investigated in situ using transmission electron microscopy (TEM), selected-area electron diffraction
and high-resolution transmission electron microscopy. The EB irradiation for 2–8 min enhanced the construction of bismuth
nanoparticles with a rhombohedral structure and diameter of 4–9 nm. The average particle size was found to increase with the
irradiation time. Bismuth metal has a melting point of 271 °C and this low melting temperature makes easy the progress of
energy induced structural changes during in situ TEM observations. This is a very useful technique in nano-patterning for
integrated optics and other applications. 相似文献
43.
Bahni Ray P. Dinesh Sankar Reddy Dipankar Bandyopadhyay Sang Woo Joo Ashutosh Sharma Shizhi Qian Gautam Biswas 《Theoretical and Computational Fluid Dynamics》2012,26(1-4):311-318
Instability of a thin electrolyte film undergoing a direct current electroosmotic flow has been investigated. The film with a compliant electrolyte–air interface is flowing over a rigid charged substrate. Unlike previous studies, inclusion of the Maxwell stresses in the formulation shows the presence of a new finite wavenumber shear-flow mode of instability, alongside the more frequently observed long-wave interfacial mode. The shear mode is found to be the dominant mode of instability when the electrolyte–solid and electrolyte–air interfaces are of opposite charge or of same charge but have very large zeta-potential at the electrolyte–air interface. The conditions for mode-switch (interfacial to shear) and the direction of the travelling waves are discussed through stability diagrams. Interestingly, the analysis shows that when the interfaces are of nearly same zeta potential, the ‘free’ electrolyte–air interface behaves more like a ‘stationary’ wall because of the ion transport in the reverse direction of the flow. 相似文献
44.
P. K. Karmakar R. Bera G. Tarafdar A. Maitra A. K. Sen 《International Journal of Infrared and Millimeter Waves》1991,12(11):1333-1348
Rain, perhaps, is the worst offender for utilising Millimeterwaves in practice. This paper describes the rain rate distribution from which millimeterwave attenuation distribution have been attempted. Results reveal that in our location (Calcutta: lat 23°N long 88.5°E) the rain rate distribution fits well with normal distribution. The cumulative distribution of rain rate also prompted the present authors to find out rain attenuation cumulative distribution for both terrestrial and earth-space paths in millimeterwave band. 相似文献
45.
Like liquid alkali metalsd-shell liquid metals show scaling behaviour in structure and interaction potentials. A realistic interaction potential model,
properly parametrized can reasonably describe the universality in the isothermal compressibility and vacancy formation energy
of 3d-liquid metals in electron ion plasma model. 相似文献
46.
The average effective pair potential energy function between two neighbouring molecules has been computed from the centre structure factor data of water and this shows an unusual feature at short range due to strong hydrogen bonding. The effective potential is highly temperature dependent and at elevated temperature it turns out to be approximately like that for simple liquids. The effective potential can be represented satisfactorily by the square well model. 相似文献
47.
Ambarish Ray Indrani Bhowmick Atish Dipankar Jana Mahammed Ali 《Journal of solid state chemistry》2009,182(10):2608-5253
A [Ni(CN)4]2−-based two-dimensional Mn(II) coordination polymer {Mn(H2O)2[NiCN]4·4H2O}, in which the coordination layers are stacked on top of each other sandwiching 2D water layer of boat-shaped hexagonal water clusters has been synthesized. The complex exhibits high thermal decomposition temperature and reversible water absorption, which were clearly demonstrated by thermal and PXRD studies on the parent and rehydrated complex after dehydration. 相似文献
48.
Susanto Chakraborty Pranab Krishna Chanda Dipankar Ray 《International Journal of Theoretical Physics》1995,34(11):2223-2244
Under some assumptions and transformations of variables, Yang's equations forR-gauge fields on Euclidean space lead to conformally invariant equations permitting one to obtain infinitely many other solutions from any solution of these conformally invariant equations. These conformally invariant equations closely resemble the mathematically interesting generalized Lund-Regge equations. Some exact solutions of these conformally in variant equations are obtained. Except for some singular situations, these solutions are self-dual. 相似文献
49.
Dipankar Mishra Subhendu Naskar Shyamal K. Chattopadhyay Milan Maji Parbati Sengupta Rupam Dinda Saktiprasad Ghosh Thomas C. W. Mak 《Transition Metal Chemistry》2005,30(3):352-356
The synthesis, crystal structure, redox and spectroscopic properties of trans-[Ru(bbpH2)(PPh3)2Cl]Cl are reported. In the crystalline solvate trans-[Ru(bbpH2)(PPh3)2cCl]Cl CHCl3 H2O, the molecular components are connected by strong intermolecular hydrogen bonding to form an infinite double column. 相似文献
50.
A. K. Sen R. Bera P. K. Karmakar 《International Journal of Infrared and Millimeter Waves》1997,18(11):2233-2257
The use of Ka Band (20/30 GHz) for future satellite communications has been addressed. The exploitation of Ka band with a
bandwidth of 2500 MHz seems to represent the largest significant achievement in satellite communications potential, so far.
The problems associated with the use of this frequency band such as attenuation and receiver noise temperature (floor) variation
with rain has been addressed. The receiver noise floor variation with rain has so far been ignored. Therefore, in view of
propagation and noise study over this Ka Band, both signal attenuation and receiver noise floor variations with rain rate
are estimated using dual frequency radiometers operating at 22.235 and 31.4 GHz over a tropical station, Calcutta, India. 相似文献