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91.
Polarizing microscopy was used to study the kinetics of formation and droplet size growth of the ordered (nematic) phase during the phase separation of an azomethine dimer melt at various rates of cooling. The statistical droplet size distribution of the nematic phase during phase separation was described by a model derived in terms of the thermodynamics of irreversible processes. Two kinetic phase separation stages were observed and described by the universal scaling function.  相似文献   
92.
医药类专业物理课程教学存在的问题及对策   总被引:2,自引:0,他引:2  
根据对国内69所普通高等院校医药类专业(本科)物理课程教学现状调查的结果,分析了在我国高等教育进入“大众化教育”的形势下,医药类专业物理课程教学中存在的4个急需解决的问题,指出了医药类专业物理课程教学改革的方向,并介绍了我们所做的一些工作。  相似文献   
93.
Black holes with a conformal scalar field are proved to be unstable under monopole perturbations.  相似文献   
94.
A study is made of the stability of previously found static spherically symmetric solutions of a multidimensional theory of gravitation with Maxwell and dilaton fields. It is shown that in the entire 4-parameter family of solutions only the solutions describing multidimensional black holes (which form a 2-parameter subfamily) are stable with respect to linear monopole perturbations. This confirms the hypothesis in accordance with which gravitational collapse leads to the formation of black holes even when additional spacetime dimensions are taken into account.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 106–110, January, 1992.  相似文献   
95.
A multidimensional generalization is obtained for the Reissner-Nordstrom solution of general relativity theory for the case of n Ricci-plane internal spaces with inclusion of the dilaton field. A two-parameter family of solutions that describe black holes of arbitrary dimensionality D is identified. It is shown that nontrivial black holes with dimensionality D > 4 exist only for nonzero electric charge. The observational consequences, particularly a violation of Coulomb's law, are discussed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 24–28, July, 1991.  相似文献   
96.
Global properties of static, spherically symmetric configurations with scalar fields of sigma-model type with arbitrary potentials are studied in D dimensions, including models where the space-time contains multiple internal factor spaces. The latter are assumed to be Einstein spaces, not necessarily Ricci-flat, and the potential V includes a contribution from their curvatures. The following results generalize those known in four dimensions: (A) a no-hair theorem on the nonexistence, in case V 0, of asymptotically flat black holes with varying scalar fields or moduli fields outside the event horizon; (B) nonexistence of particlelike solutions in field models with V 0; (C) nonexistence of wormhole solutions under very general conditions; (D) a restriction on possible global causal structures (represented by Carter-Penrose diagrams). The list of structures in all models under consideration is the same as is known for vacuum with a cosmological constant in general relativity: Minkowski (or AdS), Schwarzschild, de Sitter and Schwarzschild – de Sitter, and horizons which bound a static region are always simple. The results are applicable to various Kaluza-Klein, supergravity and stringy models with multiple dilaton and moduli fields.  相似文献   
97.
Using solution polycondensation, a new polyazomethine with m-tolylazo side groups (PAz) exhibiting thermotropic liquid crystalline phase was synthesised and its chemical structure was characterised with generally accepted methods. Its phase transition temperatures were detected with both polarising optical microscopy and differential scanning calorimetry. Using dielectric spectroscopy method, both real and imaginary parts of the permittivity were investigated in wide regions of temperature (from ?100°C to 170°C) and frequency (from 1 Hz to 1 MHz). Analysis of frequency dependent permittivity allowed finding three relaxations (α, β1 and β2) in PAz. β-relaxations were described with the Arrhenius equation, whereas α-relaxation was described with the Vogel–Fulcher–Tammann equation. The alternating current conductivity (ACC) of PAz was studied in the same regions of temperature and frequency. The frequency dependent ACC was described with an exponent power equation. Presentation of ACC as a function of inverse temperature allowed us to describe ACC with the Arrhenius equation.  相似文献   
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