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61.
Three kinds of horizon-like hypersurface of a uniformly rectilinearly accelerating, non-stationary charged black hole: event
horizon, apparent horizon and time-like limit surface are studied. The result is that the event horizon is apart from the
time-like limit surface and the apparent horizon in the case where the black hole is charged, uniformly accelerating and its
mass is varying (evaporating and accreting). Some other new results are also given.
Project supported by the National Natural Science Foundation of China. 相似文献
62.
A. González J. Bonastre L. Escoda J. J. Suñol 《Journal of Thermal Analysis and Calorimetry》2007,87(1):255-258
In this work several Fe(Co,Ni) based nanocrystalline alloys were obtained
by mechanical alloying. Thermal study was performed by differential scanning
calorimetry and thermogravimetry. After 80 h milling, all DSC scans show several
reactions on heating. At low temperature, about 400 K, the exothermal process
detected is associated to structural relaxation. In all alloys, the main crystallization
process begins over 700 K and has apparent activation energy values between
3.7 and 3.1 eV at–1. The Co content increases
the thermal stability of this process. Furthermore, thermomagnetic measurements
confirm the Co solid solution into Fe. The ferromagnetic–paramagnetic
transition occurs at about 900 K. 相似文献
63.
Kenneth S. Pitzer John R. Peterson Leonard F. Silvester 《Journal of solution chemistry》1978,7(1):45-56
The extensive data for the osmotic coefficients, heats of dilution, and densities of aqueous solutions of rare earth chlorides, nitrates, and perchlorates are fitted to a single type of equation found satisfactory for many other solutes Good agreement is obtained. The various parameters do not show simple trends with cation radius. While there are some plausible explanations of these complexities, the total picture is far from clear. 相似文献
64.
Density,viscosity, conductance,and transference number of concentrated aqueous magnesium chloride at 25°C 总被引:1,自引:0,他引:1
The density, viscosity, conductance, and transference number of aqueous magnesium chloride at 298.15°K are reported for the concentration range 0 to 5.7m. The transference numbers were determined using the emf method. It was found that the viscosity, conductance, and transference number of aqueous magnesium chloride are similar to those for aqueous nickel chloride. It was therefore tentatively concluded that incomplete dissociation and complex formation was unlikely to be of importance in nickel chloride solutions. 相似文献
65.
Abstract The performance assessment of orthogonal frequency division multiplexing signals in direct-detection transmission systems by using the error vector magnitude and several bit error ratio approaches is analyzed and compared through numerical simulation. It is shown that excellent accuracy of the bit error ratio estimates is obtained by a semi-analytical Gaussian approach for all the orthogonal frequency division multiplexing system configurations analyzed and that the error vector magnitude only provides reliable estimates of the system performance when the system is dominantly impaired by noise. Additionally, a novel Q-factor approach for orthogonal frequency division multiplexing optical signals showing improved bit error ratio estimates is also presented. 相似文献
66.
玉米支链淀粉在单糖、寡糖水溶液中的粘度行为 总被引:1,自引:0,他引:1
通过乌氏粘度计和数字流变仪研究了玉米支链淀粉在单糖和寡糖溶液中的特性粘度和表观粘度.发现在稀溶液中,玉米支链淀粉的特性粘度随糖浓度的增加而降低;浓溶液中,玉米支链淀粉的糖溶液的表观粘度随糖浓度的增加而升高.小分子糖对支链淀粉在糖溶液中的特性粘度和表观粘度的影响由强到弱依次为蔗糖>麦芽糖>葡萄糖>半乳糖>果糖. 相似文献
67.
P. Pardhasaradhi B.T.P. Madhav M. Venugopala Rao R.K.N.R. Manepalli 《Phase Transitions》2016,89(9):902-909
Characterization and phase transitions in pure and 0.5% BaTiO3 nano-dispersed liquid crystalline (LC) N-(p-n-heptyloxybenzylidene)-p-n-nonyloxy aniline, 7O.O9, com-pounds are carried out using a polarizing microscope attached with hot stage and camera. We observed that when any of these images are distorted, different local structures suffer from various degradations in a gradient magnitude. So, we examined the pixel-wise gradient magnitude similarity between the reference and distorted images combined with a novel pooling strategy – the standard deviation of the GMS map – to determine the overall phase transition variations. In this regard, MATLAB software is used for gradient measurement technique to identify the phase transitions and transition temperature of the pure and nano-dispersed LC compounds. The image analysis of this method proposed is in good agreement with the standard methods like polarizing microscope (POM) and differential scanning calorimeter (DSC). 0.5% BaTiO3 nano-dispersed 7O.O9 compound induces cholesteric phase quenching the nematic phase, which the pure compound exhibits. 相似文献
68.
Density and sound speed measurements have been carried out for the ternary systems consisting of tetra-n-butyl ammonium bromide (TBAB) in 0.1 m aqueous magnesium sulphate heptahydrate (MgSO4.7H2O)-water over the full range of composition from T = 293.15 to 318.15 K by using volumetric method. Using this experimental data, various physical and thermodynamical parameters such as adiabatic compressibility, apparent molal compressibility, apparent molal volume, apparent and limiting partial molar volumes of the electrolytes and ions in these mixtures have been evaluated and split into respective ionic contributions. The results have been discussed in terms of ion–ion and ion–solvent interactions occurring between TBAB and aqueous MgSO4 solutions. Further, structure making/breaking behaviour of MgSO4 has been reported in terms of sign of the partial molar expansibility at infinite dilution. 相似文献
69.
According to the principle of fluid mechanics,the law of laminar,helical flow of power-law fluid in eccentric annuli is studied extensively in this paper.The apparent viscosity,velocities distribution of laminar helical flow of power-law fluid are discussed and calculating methods of flow rate and pressure loss are presented.The factors influencing flow are also analysed.On the basis of theoretical studies some new results of the present paper are compared with the theories of the helical flow of the power-law fluid in concentric annuli.The test verified that theoretical formulas in this article are proper and general.They can be used for calculating hydraulic parameters in drilling engineering. 相似文献
70.
对目前利用配位吸附波测定配合物表观稳定常数的常用方法进行了修正,提出了更具有普遍适用性的测定配合物表观稳定常数的理论公式,并对计算方法进行了探讨,获得了预期的满意的结果。 相似文献