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1.
2.
LetP(z) be a polynomial of degreen which does not vanish in |z|<1. In this paper, we estimate the maximum and minimum moduli of thekth polar derivative ofP(z) on |z|=1 and thereby obtain compact generalizations of some known results, which among other results, yields interesting refinements of Erdos-Lax theorem and a theorem of Ankeny and Rivlin. 相似文献
3.
The dielectric constant, ε, and the d.c. conductivity, σ, were measured along the a-, b- and c-axes of (NH4)2ZnCl4 (AZC) crystal in the 300-450 K temperature range. Crystals of AZC grown from aqueous solutions containing excess of ZnCl2 were used. The value of the dielectric permittivity of AZC is extremely small compared to other ferroelectric crystals. Pronounced broad or step-like peaks at the phase transition temperatures were detected along the a- and b-axes, while ε along the c-axis is temperature independent up to the end of the measuring range. Reciprocal of the dielectric permittivity in the range of the commensurate to incommensurate phase transition obeys a relation similar to the Curie-Weiss law that is valid for second order ferroelectric/paraelectric phase transitions. The constants of the proposed relationship applied to the cooling run are given. The J-E characteristics along the three crystallographic axes were measured in the normal, incommensurate, commensurate and antiferroelectric phases. Hence, the type of conduction mechanism has been estimated. Parameters of Poole-Frenkel and Richardson-Schottky types of conduction mechanism have been determined. The effect of applied electric field on the conductivity measurement was also tested. Conductivity anomalies with different character were observed at the phase transition temperatures. The lnσ−1000/T dependence revealed thermal activation energy of conduction along the a-, b- and c-axes with different values in different phases of AZC. 相似文献
4.
A mathematical model of laser beam treatment of double layer alloys (Ni/Fe, Al/Fe and Cr/Fe systems) describing the effect of laser beam on different physical and geometrical parameters of coated layer system has been adapted. The numerical solutions of the non-homogeneous heat-transport differential equation could estimate the temperature of the treated region.The suggested model allows investigation of the temperature distribution as a function of treated surface and laser parameters. The physical parameters of the treated materials were taken as functions of temperature due to the change in the temperature of the treated double layer materials. 相似文献
5.
Ashfaque H. Bokhari Abdul R. Kashif Asghar Qadir 《General Relativity and Gravitation》2003,35(6):1059-1076
Curvature collineations are symmetry directions for the Riemann tensor, as isometries are for the metric tensor and Ricci collineations are for the Ricci tensor. Complete listings of many metrics possessing some minimal symmetry have been given for a number of symmetry groups for the latter two symmetries. It is shown that a claimed complete listing of cylindrically symmetric static metrics by their curvature collineations [1] was actually incomplete and is completed here. It turns out that in this complete list, unlike the previous claim, there are curvature collineations that are distinct from the set of isometries and of Ricci collineations. The physical interpretation of some of the metrics obtained is given. 相似文献
6.
Dipak Ghosh Madhumita Lahiri Argha Deb Susobhan Das Krishnadas Purkait Biswanath Biswas Jayanta Roy Choudhury Rini Chatterjee Abdul Kayum Jafry 《Zeitschrift fur Physik C Particles and Fields》1996,71(1):243-249
The scaled factorial moments and the multifractal moments have been investigated in differentη-intervals to study the dynamical fluctuation of pions produced in 200 AGeV32S-Ag/Br interaction. In order to investigate the detail characteristics of intermittency behaviour, theF-moments are extracted up to the eighth order of moments in differentM-intervals. The analysis indicates a non-thermal phase transition and different regime of particle production during the hadronisation process. 相似文献
7.
Sk. Asrof Ali Yunusa Umar B. F. Abu‐Sharkh Hasan A. Al‐Muallem 《Journal of polymer science. Part A, Polymer chemistry》2006,44(19):5480-5494
The cycloterpolymerizations of single‐, twin‐, and triple‐tailed hydrophobes with hydrophilic monomer N,N‐diallyl‐N‐carboethoxymethylammonium chloride and sulfur dioxide afforded a series of cationic polyelectrolytes (CPEs) in excellent yields. These CPEs, upon the acidic hydrolysis of the pendent ester groups, gave the corresponding pH‐responsive cationic acid salts, which, upon a treatment with sodium hydroxide, were converted to polybetaines (PBs), anionic polyelectrolytes (APEs), and PB/APE polymers containing various proportions of zwitterionic (PB) and anionic fractions (APE) in the polymer chain. At a shear rate of 0.36 s−1 at 30 °C, salt‐free water solutions of the CPEs (2 g/dL) containing 8, 4, and 2.67 mol % of the single‐, twin‐, and triple‐tailed hydrophobes (all having 8 mol % octyloxy tails) had apparent viscosity values of 70, 2800, and 396,000 cps, respectively. The PB/APE polymer with a ratio of 33:67 for the zwitterionic and anionic fractions in the polymer chain gave the highest viscosity value. The superior viscosity behavior of the polymers containing the triple‐tailed hydrophobe was attributed to the blocky nature of the comonomer. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5480–5494, 2006 相似文献
8.
Anwar Usman Ibrahim Abdul Razak Hoong‐Kun Fun Suchada Chantrapromma Yan Zhang Jian‐Hua Xu 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(5):o287-o288
In the title compound, C18H13BrClNO3, the heterocyclic ring of the indole is distorted from planarity towards an envelope conformation. The orientations of the indole, oxetane, chloro and bromophenyl substituents are conditioned by the sp3 states of the spiro‐junction and the Cl‐attached C atoms. 相似文献
9.
M.I. Bruce O.M.Abu Salah R.E. Davis N.V. Raghavan 《Journal of organometallic chemistry》1973,64(3):C48-C50
In contrast to a related iron—copper compound, the complex (π-C5H5)Ru(PPh3)2(C2Ph)CuCl is shown to be monomeric, and contains linear dicoordinate copper(I); the reactions of this and similar complexes with metal carbonyls are sources of new mixed-metal clusters, such as (π-C5H5)Fe2 Ru(C2Ph)(CO)6 (PPh3). 相似文献
10.
Norimah Yusof A.H. Ainul Hafiza Rozaini M. Zohdi Md Zuki A. Bakar 《Radiation Physics and Chemistry》2007,76(11-12):1767-1770
Radiation at 25 and 50 kGy showed no effect on the acidic pH of the local honey, Gelam, and its antimicrobial property against Staphylococcus aureus but significantly reduced the viscosity. Honey stored up to 2 years at room temperature retained all the properties studied. Radiation sterilized Gelam honey significantly stimulated the rate of burn wound healing in Sprague-Dawley rats as demonstrated by the increased rate of wound contraction and gross appearance. Gelam honey attenuates wound inflammation; and re-epithelialization was well advanced compared to the treatment using silver sulphadiazine (SSD) cream. To enhance further the use of honey in wound treatment and for easy handling, Gelam honey was incorporated into our hydrogel dressing formulation, which was then cross-linked and sterilized using electron beam at 25 kGy. Hydrogel with 6% of honey was selected based on the physical appearance. 相似文献