Observational manifestations of black holes in the Horndeski gravity model

The geodesic equations for black hole solutions in the scalar–tensor Horndeski gravity model with non-minimal kinetic coupling have been investigated. The ranges of model parameters admitting the existence of bounded orbits have been determined. Constraints on the model parameters providing agreement of the model with the observational data on the accretion and motion of bodies in the Solar system have been obtained.     

描述氨水体系VLE行为适宜热力学模型的研究

基于对氨／水体系气液平衡研究的文献调查,选择了Ｇｕｉｌｌｅｖｉｃ等提出的一套等温数据为工作基础,本文研究了状态方程法与活度系数法对氨／水体系气液平衡性质预测的适用性．其中状态方程法分别选用理想体系的计算方法、ＢＷＲ方程、ＳＲ－Ｐｏｌａｒ方程、ＬＫ－Ｐ方程和ＲＫＳ方程;活度系数法是基于气相选用ＲＫＳ方程,液相分别选用ＮＲＴＬ模型、电解质ＮＲＴＬ模型、ＵＮＩＱＵＡＣ模型、ＵＮＩＦＡＣ模型和Ｗｉｌｓｏｎ方程。本研究发现,活度系数法并没有良好表现,而 ＬＫ－Ｐ方程和 ＲＫＳ方程对氨／水体系气液平衡性质预测的适用性显然优于其它方法。     

Study of critical properties of the frustrated antiferromagnetic Heisenberg model on a triangular lattice

The replica Monte Carlo method has been applied to study critical properties of the three-dimensional frustrated antiferromagnetic Heisenberg model on a layered triangular lattice. Magnetic and chiral critical exponents for this model have been calculated within the finite-size scaling theory. The data for this model have been analyzed for the first time taking into account corrections to scaling. It has been shown that the critical behavior of the frustrated antiferromagnetic Heisenberg model on the triangular lattice differs from the critical behavior of the pure Heisenberg model and is independent of the type of interlayer exchange interaction.     

Calculation of the intensity of Touschek electrons in the VEPP-4M storage ring

Formulas for calculating the intensity of intrabeam scattering of electrons in the Born approximation for the one- and two-dimensional collision models have been obtained for the nonrelativistic and relativistic cases. The Baier-Katkov-Strakhovenko two-dimensional relativistic model with Coulomb corrections has been analyzed. Formulas in the ultrarelativistic limit have been obtained using this model. Different models have been compared. The intensities of Touschek electrons and the polarization contribution have been calculated under the conditions of the detection of scattered particles at the VEPP-4M storage ring. The calculations have been compared to experimental data.     

Simulations of dynamic resistive evaporation in a vacuum

The model of dynamic resistive evaporation in vacuum has been considered, and the model takes into account the structural peculiarities of the corresponding evaporator. In the model, the dependences to determine the time of material heating up to evaporation temperature as well as dynamic characteristics of the evaporation have been obtained. It has been shown that the obtained characteristics are nonharmonic and periodically repeated. The adequacy of the developed model to the physical model has been corroborated. It has been found that the discrepancy between the experimental and calculated time characteristics of shutter movement is not higher than 5%. The recommendations for using the suggested model to fabricate of thin films of multicomponent materials via thermal evaporation have been considered.     

A simple model of triton

A model of triton has been considered in which three interactions between nucleons have been approximated by harmonic oscillator forces of different strengths. The parameters have been determined by fitting the mass radius, the charge radius and the binding energy of the triton. The model involves an exact solution of the threebody problem. The wave function parameters and various physical parameters of the triton have been calculated. The assessment of the neutron-neutron interaction has been obtained irrespectively of the charge independence of nuclear forces. The model provides the possibility of testing the fulfilment of charge independence using the neutron-proton interaction only.     

Theoretical Study on the Gain and Tuning Characteristics of Miniature Optically Pumped NH3 Submillimeter Laser

The gain and the tuning characteristics of miniature optically pumped super-radiant NH₃ submillimeter-wave gas laser have been studied theoretically based on the quantum density matrix equations. The density matrix equations of three-level quantum system have been solved, and the gain and the output density versus different frequency detuning of submillimeter laser and infrared pumping laser have been calculated respectively by means of iteration method. The characteristic curves corresponding to ideal monochromatic IR pumping model and broadened IR pumping model have been obtained. Meanwhile, the tuning and the nonlinear properties of the system have been revealed.     

Cyclic period-3 window in antiferromagnetic potts and Ising models on recursive lattices

The magnetic properties of the antiferromagnetic Potts model with two-site interaction and the antiferromagnetic Ising model with three-site interaction on recursive lattices have been studied. A cyclic period-3 window has been revealed by the recurrence relation method in the antiferromagnetic Q-state Potts model on the Bethe lattice (at Q < 2) and in the antiferromagnetic Ising model with three-site interaction on the Husimi cactus. The Lyapunov exponents have been calculated, modulated phases and a chaotic regime in the cyclic period-3 window have been found for one-dimensional rational mappings determined the properties of these systems.     

Phase transitions in the antiferromagnetic Heisenberg model on a layered triangular lattice with the next-nearest neighbor interactions

Phase transitions in the three-dimensional antiferromagnetic Heisenberg model on a layered triangular lattice with the next-nearest neighbor interactions have been studied by the histogram Monte Carlo method. Phase transitions in this model have been studied in the range of the next-nearest neighbor interactions from 0.0 to 1.0. The first-order phase transition has been revealed in the considered interval in the studied model.     

CALCULATION OF DEMAGNETIZATION CURVES OF NANOCOMPOSITE Pr2Fe14B/α－Fe MAGNETS USING A ONE-DIMENSIONAL MODEL

The demagnetization curves of nanocomposite magnets have been calculated using a one-dimensional model. The results are in agreement with experimental results. The shoulders of the demagnetization curve have also been explained based on the model.     

一种新型TNLCD光学模型及其应用

提出一种型LCD光学模型并采用计算机模拟,应用液晶显示屏电极显露问题的量化分析,成功地解释了有关现象,并提出相应的解决方法,且获得印证。     

FRW Cosmology with Variable G and Λ

We have considered a cosmological model of the FRW universe with variable G and Λ. The solutions have been obtained for flat model with particular form of cosmological constant. The cosmological parameters have also been obtained for dust, radiation and stiff matter. The statefinder parameters are analyzed and have shown that these depends only on w and ε. Further the lookback time, proper distance, luminosity distance and angular diameter distance have also been calculated for our model.     

Optical model analysis of90, 92, 94, 96Zr+4He elastic scattering at 35.4 MeV

The elastic scattering data of 35.4 MeV alpha particles from Zr-isotopes have been analysed using the optical model. Both the phenomenological and the folding model potentials have been employed in fitting the data with the optical model. The resultant systematics. concerning the volume integrals and the root mean square radii are summarized.     

Temperature variation of the Debye-Waller factors of metal and halide ions in CsCl and CsBr powders by X-ray diffraction. II. Debye-Waller factors of Cs+ and Br− ions in CsBr from room temperature to 78.2°K

The temperature variation of the Debye-Waller factors of Cs⁺ and Br⁻ ions in CsBr powder has been studied using powder X-ray diffraction. The integrated intensities of the Bragg peaks at different temperatures have been obtained. These results have been verified by structure factor least squares refinement program. Theoretical shell model lattice dynamical calculations have been done using a 7-parameter model in the harmonic approximation and the values compared with the present X-ray measurements. The observed intensities have been corrected for first order thermal diffuse scattering.     

Optical functions of tris (8-hydroxyquinoline) aluminum (Alq3) by spectroscopic ellipsometry

Optical functions of tris (8-hydroxyquinoline) aluminum (Alq₃) have been studied in the spectral range from 1.55 eV to 5 eV using spectroscopic ellipsometry. The samples have been deposited by thermal evaporation on glass substrates. Optical functions of Alq₃ deposited on unheated substrates and on substrates kept at 100 °C have been determined. The optical functions have been modeled using point-to-point fitting, with the conventional oscillator model and modified oscillator model. It has been found that point-to-point fitting gives the best agreement with the experimental data, and that the modified oscillator model yields better agreement with the experimental data than the conventional oscillator model. Received: 3 September 2001 / Accepted: 22 March 2002 / Published online: 5 July 2002 RID="*" ID="*"Corresponding author. Fax: +852-2559/8738, E-mail: dalek@eee.hku.hk     

Theoretical Study of Millimeter Wave Harmonic Oscillator Stabilized with a Transmission Cavity

An equivalent circuit model of millimeter wave second harmonic oscillator stabilized with a transmission cavity has been proposed for constructing analytical formulations between performance parameters of the oscillator and parameters of the circuit. The model consists of an equivalent circuit of fundamental wave and that of second harmonic wave. Each of the circuits comprises circuit models of main cavity, transmission waveguide, and transmission cavity. Absorbing material placed between the transmission waveguide and the transmission cavity can suppress additional resonances originated from transmission cavity. The behavior of the second harmonic oscillator can be effectively described by the circuit model. Furthermore, based on this model, mechanical tuning characteristics have been studied at first, and then analytical formulas for quality factor and efficiency depending on circuit parameters have been derived. The circuit parameters can be conveniently extracted by electromagnetic field simulation. Hence the formulas exhibit both compact form and enough accuracy. Thereafter, general rules of performance parameters varying with circuit parameters have been deduced for the harmonic oscillators. Then some design considerations have been derived according to the corresponding analysis. The equivalent circuit model is useful for designing and adjusting millimeter wave second harmonic stabilizing oscillator with a transmission cavity.     

Observation of hydrogen pellet ablation material flow by tomography

An H\al emission measurement array with 25 detection channels has been built on HL-1M tokamak. Reconstruction maps of H\al emission distribution in plasma cross-section have been obtained by using tomography, with a hydrogen pellet injected into the plasma. The dimension, the shape and the rotation characteristic of the cross-section of the pellet ablation material flow tube have been observed. These results have been analysed and explained tentatively by using the `tail' model and the linear expansion model.     

Measurement of the neutron-induced deuteron breakup reaction cross-section between 5 and 25 MeV

High-spin states in ¹⁸⁷Pt have been studied by means of ??-ray spectroscopy techniques. Known bands have been significantly extended and new bands have been found. The band structures are discussed in the framework of the cranking model and negative-parity states are compared with calculations performed with a semi-microscopic axial-rotor plus one-quasiparticle coupling model. Shape coexistence is observed from low excitation energy.     

Lattice dynamics of hcp metals

A lattice dynamical model for hcp metals has been developed which considers ion-ion interaction as a five-neighbour central pair potential and electron-ion interaction in a modified form of Bhatia's model. Complete account of the equilibrium of the hcp lattice including the effect of electron pressure has been considered and as a consequence two equilibrium conditions, necessary for the hcp structure, have been obtained and used in the study. Phonon dispersion curves for four hcp metals, Be, Mg, Y and Ho have been computed for two symmetry directions and a good agreement has been obtained with the neutron data. The results have also been compared with the use of the same model but with a single condition, reported earlier and show in general a significant improvement.