新型超快探测器性能研究

 为提高强g 场超快辐射探测器抗信号堆积的性能，可采用BaF₂（La）与快的光电器件组合的技术途径。用同步辐射闪烁荧光衰减谱仪和X光激发发射谱仪测量了国产不同掺La浓度的BaF₂晶体抑制快慢成分之比，探讨掺La对抑制慢成分的机理，研究了BaF₂（La）抗辐照性能。并用同步辐射测量BaF₂（La）与GD40Z光电管组成超快辐射探测器的快慢成分抑制比。     

Transient simulation of 2–3D stratified and intermittent two-phase flows. Part II: Applications

In this paper a new type of transient multidimensional two-fluid model has been applied to simulate intermittent or slug flow problems. Three different approaches to modelling interfacial friction, including an interfacial tracking scheme, have been investigated. The numerial method is based on an implicit finite difference scheme, solved directly in two steps applying a separate equation for the pressure. 2D predictions of Taylor bubble propagation in horizontal and inclined channels have been compared with experimental data and analytical solutions. The 2D model has also been applied to investigate a number of special phenomena in slug flow, including slug initiation, bubble turning in downflow and the bubble centring process at large liquid flow rates.     

Non-Fourier heat conduction with radiation in an absorbing, emitting, and isotropically scattering medium

This article numerically analyses the combined conductive and radiative heat transfer in an absorbing, emitting, and isotropically scattering medium. The non-Fourier heat conduction equation, which includes the time lag between heat flux and the temperature gradient, is used to model the conductive heat transfer in the medium. It predicts that a temperature disturbance will propagate as a wave at finite speed. The radiative heat transfer is solved using the P₃ approximation method. In addition, the MacCormack's explicit predictor-corrector scheme is used to solve the non-Fourier problem. The effects of radiation including single scattering albedo, conduction-to-radiation parameter, and optical thickness of the medium on the transient and steady state temperature distributions are investigated in detail. Analysis results indicate that the internal radiation in the medium significantly influences the wave nature. The thermal wave nature in the combined non-Fourier heat conduction with radiation is more obvious for large values of conduction-to-radiation parameter, small values of optical thickness and higher scattering medium. The results from non-Fourier-effect equation are also compared to those obtained from the Fourier equation. Non-Fourier effect becomes insignificant as either time increases or the effect of radiation increases.     

Transient coupled radiation-conduction in infinite semitransparent cylinders

A method is developed to analyze the transient coupled radiation-conduction in infinite semitransparent cylinders surrounded by isothermal black walls. The radiative heat source term is calculated by the radiative transfer coefficients and the transient energy equation is solved by an implicit finite difference method. The radiative transfer coefficients are deduced by use of the ray tracing method in combination with the Hottel and Sarofim zonal method. The effects of the related parameters on the transient radiative heat source and temperature distribution are analyzed. It is found that the peak of the dimensionless radial radiative heat source can be located at the interior shell of the cylinder with small optical thickness when heated by the surrounding irradiation. Treating the volume radiation as a surface radiation will result in large errors of transient temperature distribution for the cylinder with small optical thickness.     

Simultaneous maneuver and vibration suppression of flexible spacecraft

A method is described for the simultaneous large-angle maneuver and vibration suppression of flexible spacecraft. The control action is carried out in two independent systems, one system performing the maneuvers and the other system controlling the elastic motion. The vibration is suppressed using a natural control. It is shown that control of the elastic motion does not distort the maneuver because the spacecraft linear and angular momenta are conserved regardless of spacecraft modeling errors. Thus, the maneuver can be designed and performed independently of the elastic motion control.     

Transient Behaviour of an M/M/1/N queue

For a simple queue with finite waiting space the difference equations satisfied by the Laplace transforms of the state probabilities at finite time are solved and the state probabilities have been obtained. The method economizes in algebra and the simple closed form of the state probabilities is used to obtain important parameters.     

Importance of the counterion in optimization of a borate electrolyte system for analyses of anions in samples with complex matrices performed by capillary zone electrophoresis

Borate buffers are common background electrolytes for analyses of anions in capillary zone electrophoresis. Usually, sodium borate at a given pH is used and this specification seems to be sufficient for a successful analysis. In this paper, we show that free migration of OH(-) may deteriorate the analysis of a typical anionic analysis of clinical samples due to uncontrolled migration of OH(-) throughout the systems of analyzed zones and may damage the stacking of anionic analytes of interest. We have proven that the use of ammonium borate may remedy the situation where the presence of ammonium may selectively stop the free migration of OH(-) ions, slow down their effective mobility and bring their safe behavior resulting in reproducible stacking of clinically important anions. Results of real analyses of human serum samples confirmed the proposed method and proved that substitution of sodium for ammonium in borate buffers offers reliable analyses of clinical samples having chloride as the bulk component. The experimental results given in this paper are supported also by computer simulation, which can not only support the positive results but also show the dynamics of the separation that is otherwise hidden to any detection possibilities.     

Integrated design of piezoelectric damping system for flexible structure

This paper aims at developing an integrated design method of the active/passive hybrid type of piezoelectric damping system for reducing the dynamic response of the flexible structures due to external dynamic loads. The design method is based on the numerical optimization technique whose objective function is a control effort of the active damping. A vibration suppression performance, which is evaluated by the maximum value of the gain of the frequency response function of the structure, is constrained. In order to demonstrate the structural damping capability of the hybrid type of piezoelectric damping system designed by proposed method, numerical simulation and laboratory experiment will be done using a three-story flexible structure model equipped with 12 surface bonded PZT tiles pairs. Both numerical and experimental results indicate that the optimally designed hybrid piezoelectric damping system can be successfully achieving excellent performance as compared to a conventional purely active piezoelectric damping system.     

Dipionic decays of psions in a local derivative coupling model

A local derivative coupling model is used to study theφ′→ππ and other dipionic decays ofφ andφ″, as an alternative to theε-model. The results obtained are quite satisfactory. We findt hat the existence of theε-resonance is not essential in order to understand the dipionic decays of the psions at the present level of experimental data available. A preliminary version of this paper was presented at the 3rd High Energy Phys. Symp. held in Nov. 1976 at Bhubaneswar.     

Plastic Versus Glass Support for an Immunoassay on Metal-Coated Surfaces in Optically Dense Samples Utilizing Directional Surface Plasmon-Coupled Emission

We compared plastic (polycarbonate) and high-quality glass support materials for gold-coated slides, when performing a model immunoassay against rabbit IgG using fluorescently labeled (AlexaFluor-647) anti-rabbit IgG, and detecting surface plasmon-coupled emission (SPCE) signals. Both, glass and plastic slides were simultaneously coated with a 48-nm layer of gold and protected with a 10-nm layer of silica. The maximum SPCE signal of AlexaFluor-647 was only two- to three-fold smaller on plastic slides than on glass slides. A small difference in the SPCE angles on glass (θ _F = 55°) and plastic (θ _F = 52.5°) slides was observed and can be explained with a slightly smaller refractive index of the plastic. We have not found any difference in the angle distribution (sharpness of the fluorescence signal at optimal SPCE angle) for the plastic slide compared to the glass slide. The kinetics of binding was monitored on the plastic slide as well as on the glass slide. Optically dense samples, a 4% red blood cell suspension and a 15% hemoglobin solution, are causing a reduction in the immunoassay SPCE signal by approximately 15% and three times, respectively, and the percentage of the reduction is the same for plastic and for glass slides. We believe that plastic substrates can be readily used in any SPCE assay, with only marginally lower total signal compared to high-quality glass slides.