排序方式: 共有42条查询结果,搜索用时 796 毫秒
1.
S. N. Achary B. R. Ambekar M. D. Mathews A. K. Tyagi P. N. Moorthy 《Thermochimica Acta》1998,320(1-2):239-243
Volume thermal expansion behaviour of a number of rare-earth oxyfluorides (REOF) have been studied using high-temperature X-Ray diffractometry (HT-XRD) in the 298–1075 K range in air. The studies revealed an anomalous expansion for each compound associated with phase transition. The phase transition temperature and the coefficient of volume thermal expansion of five compounds in REOF series determined by this method are reported and compared with our earlier results obtained by dilatometry. 相似文献
2.
3.
Physics of the Solid State - The synthesis of the perovskites BiSmO3 was done by the solid-state reaction method. In this communication, the structural and detailed electrical (dielectric,... 相似文献
4.
K. K. Mishra S. Nagabhusan Achary Sharat Chandra T. R. Ravindran K. K. Pandey Avesh K. Tyagi Surinder M. Sharma 《ChemInform》2016,47(13):no-no
The title compound is synthesized by solid state reaction of a stoichiometric mixture of BaCO3 and TeO2 (air, 550 °C for 6 h, and 650 °C for 12 h). 相似文献
5.
A recently developed coupled third-order zigzag theory for the statics of piezoelectric hybrid cross-ply plates is extended
to dynamics. The theory combines a third-order zigzag approximation for the in-plane displacements and a sub-layerwise linear
approximation for the electric potential, considering all components of the electric field. The nonuniform variation of the
transverse displacement due to the piezoelectric field is accounted for. The conditions for the absence of shear traction
at the top and bottom surfaces and continuity of transverse shear stresses in the presence of electromechanical loading are
satisfied exactly, thereby reducing the number of displacement variables to five, which is the same as in a first- or third-order
equivalent single-layer theory. The governing equations of motion are derived from the extended Hamilton's principle. The
theory is assessed by comparing the Navier solutions for the free and forced harmonic vibration response of simply supported
plates with the exact three-dimensional piezoelasticity solutions. Comparisons for hybrid test, composite and sandwich plates
establish that the present theory is quite accurate for the dynamic response of moderately thick plates. 相似文献
6.
Here we report the results of combined powder X-ray and neutron diffraction studies of Bi4?x Nd x Ti3O12 (0.0 ≤ x ≤ 2.0) compositions. The parent Bi4Ti3O12 has an orthorhombic lattice (space group: B2cb) with unit cell parameters a = 5.4432(5) Å, b = 5.4099(5) Å and c = 32.821(2) Å, and V = 966.5(1) Å3. This orthorhombic lattice is retained in all the studied compositions. The unit cell parameters gradually decrease with Nd3+ ion concentration with a discontinuity at x = 0.75. Orthorhombicity of the lattice decreases with increase in Nd3+ content in the lattice. The orthorhombic unit cell parameters for a representative Bi2Nd2Ti3O12 composition are: a = 5.3834(9), b = 5.3846(9) and c = 32.784(1) Å. The observed orthorhombic distortion at x = 2.0 is very small and thus the crystal structure apparently has a pseudo-tetragonal lattice. In addition, Nd3+ preferentially substitutes in the perovskite slab of the Aurivillius structure. The fraction of Nd3+ in the fluorite slab increases with increase in Nd3+ contents. 相似文献
7.
In this paper the use of the generalised λ-type distribution (GLD) is proposed for the analysis of standard inventory problems. Using this distribution to approximate the lead time demand distribution we analyse the generalised newsboy problem and a (Q, r) policy. The standard inventory measures like optimal order size, reorder level, average demand lost, etc. are obtained under the GLD and are compared with those given by Shore's approximation and also under exact distributional assumptions. Through a numerical study the various inventory measures are compared using the GLD and Shore's approximation with the exact distributions. The comparison reveals that the GLD approximation is better suited than Shore's approximation to model the lead time demand. 相似文献
8.
H. P. Sachin G. Achary S. Shiva Kumara Y. Arthoba Naik T. V. Venkatesha 《Russian Journal of Electrochemistry》2007,43(2):204-210
The electrochemical reduction of nitro group of orthonitroaniline (ONA) is carried out on Pb, Cu, and Sn electrodes. The effect
of current density, temperature, and acid concentration on product yield is studied. The polarization curve for ONA in acidic
condition is recorded. Under preparative electrolysis, ONA gives a mixture of hydroxylamine and phenylenediamine, the proportion
of phenylenediamine increasing with the electrolysis time. The product formation is confirmed by thin-layer chromatography,
melting-point test, UV-visible, IR, and NMR methods. The operating conditions are optimized for a good yield of orthophenylenediamine.
The catalytic activity of different metals for the reduction of nitro group is discussed. The percent yield of orthophenylenediamine
is found to be high on the lead electrode.
Published in Russian in Elektrokhimiya, 2007, Vol. 43, No. 2, pp. 215–221.
The text was submitted by the authors in English. 相似文献
9.
S. Meenakshi V. Vijayakumar S.N. Achary 《Journal of Physics and Chemistry of Solids》2011,72(6):609-612
The results of high-pressure angle dispersive X-ray diffraction measurements up to 34.3 GPa on the double perovskite Ba2MgWO6 are presented. The ambient rock salt phase (SG: Fm-3m) is found to be stable up to the highest pressure of the present measurements. The third order Birch-Murnaghan equation of state when fitted to pressure-volume data, yielded a zero pressure bulk modulus (B0),and its first and second pressure derivatives as 137.0(81) GPa, and 3.9(5) and −0.03 GPa−1, respectively. 相似文献
10.
S. N. Achary O. D. Jayakumar S. J. Patwe A. B. Shinde P. S. R. Krishna S. K. Kulshreshtha A. K. Tyagi 《Pramana》2008,71(5):941-946
Herein we report the results of detailed crystallographic studies of Ca1−x
Ba
x
Zr4P6O24 compositions from combined Rietveld refinements of powder X-ray and neutron diffraction data. All the studied compositions
crystallize in rhombohedral lattice (space group R-3 No. 148). A continuous solid solution is concluded from the systematic
variation of unit cell parameters. The variation of unit cell parameters with the composition indicates decreasing trend in
a parameter with increasing Ba2+ concentration contrast to an increasing trend in c parameter.
相似文献