边界扫描测试在数字电路自动测试系统中的研究与应用[BT)]

边界扫描测试是当前数字电路模块故障隔离的主要手段,但测试能力受到模块可测试性设计限制,其它方面作用也被忽略。文中对数字电路自动测试系统设计提出了边界扫描测试应用技术,包括系统自检测试,模块功能测试和模块故障隔离。在系统自检测试中应用边界扫描,提高了设备自检故障隔离精度;而对于模块功能测试,边界扫描测试技术提供了一种新的选择;在故障隔离中扩展和延伸应用边界扫描技术,突破了模块自身测试性的限制,提高了边界扫描测试的故障覆盖率和故障隔离精度。通过实际测试验证表明,该设计方法稳定可靠,同时提升了测试系统自身和模块的测试能力和隔离精度。     

Normal modes and quality factors of spherical dielectric resonators: I — shielded dielectric sphere

Electromagnetic theoretic analysis of shielded homogeneous and isotropic dielectric spheres has been made. Characteristic equations for the TE and TM modes have been derived. Dielectric spheres of radii of the order of μm size are found suitable for the optical frequency region whereas for the microwave region radii of the order of mm size are found suitable. Parameters suitable for their application in the optical and microwave frequency ranges have been used to compute the frequencies corresponding to the normal modes for the TE and TM modes. Expressions for the quality factors for realistic resonators, i.e., for a dielectric sphere with a non-zero conductivity and a metal shield with a finite conductivity have also been derived for the TE and TM modes. Computations of the quality factors have been made for resonators with parameters suitable for the optical and the microwave regions.     

Structural and Thermodynamic Peculiarities of Core-Shell Particles at Fluid Interfaces from Triangular Lattice Models

A triangular lattice model for pattern formation by core-shell particles at fluid interfaces is introduced and studied for the particle to core diameter ratio equal to 3. Repulsion for overlapping shells and attraction at larger distances due to capillary forces are assumed. Ground states and thermodynamic properties are determined analytically and by Monte Carlo simulations for soft outer- and stiffer inner shells, with different decay rates of the interparticle repulsion. We find that thermodynamic properties are qualitatively the same for slow and for fast decay of the repulsive potential, but the ordered phases are stable for temperature ranges, depending strongly on the shape of the repulsive potential. More importantly, there are two types of patterns formed for fixed chemical potential—one for a slow and another one for a fast decay of the repulsion at small distances. In the first case, two different patterns—for example clusters or stripes—occur with the same probability for some range of the chemical potential. For a fixed concentration, an interface is formed between two ordered phases with the closest concentration, and the surface tension takes the same value for all stable interfaces. In the case of degeneracy, a stable interface cannot be formed for one out of four combinations of the coexisting phases, because of a larger surface tension. Our results show that by tuning the architecture of a thick polymeric shell, many different patterns can be obtained for a sufficiently low temperature.     

Tracing of interference fringes using average gray value and simultaneous row and column scan

An algorithm for computer tracing of interference fringes is reported. The method uses the average gray-level value for thresholding, row and column scans for determining the type of the scan and simultaneous row and column scan for tracing. The proposed method yield good result even for low-contrast and high-noise images. The program for the interferogram tracing was written using MATLAB6.     

Tritium Content and Salinity of Some Groundwaters in Greater Cairo Water Supply Stations

Abstract

Groundwaters from some wells, used for potable water supply from three drinking water stations at Greater Cairo in El-Ameria, El-Harem and Joli Ville, were sampled for tritium measurement. The wells with low tritium content are very suitable for drinking purpose due to the high residence time indicating that the groundwater was away from surface contaminations for a longer time. The pumping of the production wells should be restricted to deep wells of low salinity for drinking purpose. General recommendations are given for the proper approach for exploiting groundwater as a useful and cheap source for drinking water in Greater Cairo.     

氢化物发生-原子荧光光谱法测定淡水鱼中砷和汞

应用AFS820双道原子荧光光度计同时测定鱼肉、鱼骨中的砷和汞含量,样品采用湿消解法和干灰化法。结果表明,砷和汞在鱼骨中富集量高于鱼肉。该方法对砷、汞的检出限均小于0.06μg/L,RSD（n=5）：砷〈4.8%、汞〈6.2%,回收率分别为90%—118%和92%—115%。     

Increasing the performance of tritium analysis by electrolytic enrichment†

Several improvements are described for the existing tritium enrichment system at the Isotope Hydrology Laboratory of the International Atomic Energy Agency for processing natural water samples. The improvements include a simple method for pretreatment of electrolytic cells to ensure a high tritium separation factor, an improved design of the exhaust system for explosive gases, and a vacuum distillation line for faster initial preparation of water samples for electrolytic enrichment and for tritium analysis. Achievements included the reduction of variation of individual enrichment parameters of all cells to less than 1% and an improvement of 50% of the stability of the background mean. It resulted in an improved detection limit of less than 0.4 TU (at 2s), important for application of tritium measurements in the future at low concentration levels, and resulted in measurement precisions of±0.2 TU and±0.15 TU for liquid scintillation counting and for gas proportional counting, respectively.     

The radio frequency conductivity of some aliphatic alcohols at different temperatures

Activation energies for viscous flow and conductivity are computed from experimental values of RF conductivity (frequency 400 kHz) at different temperatures for eight polar liquids. It is observed that for aliphatic alcohols the activation energy for conductivity is greater than that for viscous flow. However, their ratio is slightly greater than unity and is different for different alcohols whereas for nonassociating polar liquids the ratio is almost equal to unity. The dependence of conductivity on viscosity for the liquid alcohols does not follow the Walden’s law but can be well represented by Adamczewskis relation.     

Maps and inverse maps in open quantum dynamics

Two kinds of maps that describe evolution of states of a subsystem coming from dynamics described by a unitary operator for a larger system, maps defined for fixed mean values and maps defined for fixed correlations, are found to be quite different for the same unitary dynamics in the same situation in the larger system. An affine form is used for both kinds of maps to find necessary and sufficient conditions for inverse maps. All the different maps with the same homogeneous part in their affine forms have inverses if and only if the homogeneous part does. Some of these maps are completely positive; others are not, but the homogeneous part is always completely positive. The conditions for an inverse are the same for maps that are not completely positive as for maps that are. For maps defined for fixed mean values, the homogeneous part depends only on the unitary operator for the dynamics of the larger system, not on any state or mean values or correlations. Necessary and sufficient conditions for an inverse are stated several different ways: in terms of the maps of matrices, basis matrices, density matrices, or mean values. The inverse maps are generally not tied to the dynamics the way the maps forward are. A trace-preserving completely positive map that is unital cannot have an inverse that is obtained from any dynamics described by any unitary operator for any states of a larger system.     

Respiratory and laryngeal contributions to maximum phonation duration

Maximum phonation duration (MPD) is a common assessment procedure in speech-language pathology. However, the specific contributions of the respiratory and phonatory components of the speech-production mechanism to this task are not typically assessed. Six women and 6 men with normal speech and voice were monitored for lung volume during a standard MPD task, and for laryngeal airway resistance (Rlaw) during a modified MPD (slow syllable-repetition) task. On average, subjects used 90% of their vital capacity (VC) for their best MPD trial. There was no systematic relation between MPD and VC for these subjects. Rlaw was strongly correlated with MPD for the men (r(s) = 0.886 for /a/; r(s) = 0.829 for /i/), but not for the women. Rlaw increased linearly as lung volume decreased (slope > 0.15) for a subset of trials (32%). This was a common pattern for four of the subjects. The clinical utility of MPD to assess breathing for speech is questioned because of the lack of association between MPD and VC, and some atypical laryngeal-valving strategies.     

Exact solution of a coagulation equation with a product kernel in the multicomponent case

In this paper, we obtain the general solution for the continuous Smoluchowski equation in the multicomponent case with a product kernel as a series expansion. The solution of the problem involves the Laplace transform in several dimensions. We obtain a nonlinear partial differential equation (PDE) of the advective kind generalizing the one previously given by other authors for the mono-component case.As in its relative mono-component case, gelation is produced at some point, the conditions for its occurrence being the same as those for the mono-component case, though substituting a sum of derivatives by a derivative in the Laplace transform field. We demonstrate that for a multicomponent particle size distribution (PSD) of multiplicative form, it is sufficient for one of the marginal PSDs to generate instantaneous gelation for the occurrence of instantaneous gelation in the multicomponent PSD.The general solution is applied to several specific cases, a discrete case that recovers a previously known solution, and another two continuous cases which can be used to check numerical methods designed to directly solve the Smoluchowski equation in more general cases.We have compared the solutions for the multicomponent PSD for constant, additive and product kernels and we conjecture about the relation existing between the functional forms for the solutions both in the mono-component and the multicomponent case.Finally, we have analysed the shape of the solutions for multicomponent PSD for constant, additive and product kernels for very small masses of components, obtaining a qualitatively different behaviour for the product kernel. This has effects in the mixing state of the sol phase as time passes.     

Feynman integral and perturbation theory in quantum tomography

We present a definition for tomographic Feynman path integral as representation for quantum tomograms via Feynman path integral in the phase space. The proposed representation is the potential basis for investigation of Path Integral Monte Carlo numerical methods with quantum tomograms. Tomographic Feynman path integral is a representation of solution of initial problem for evolution equation for tomograms. The perturbation theory for quantum tomograms is constructed.     

FAAS测定电解镉中的Zn、Cu和Fe

采用火焰原子吸收光谱法测定电解镉中铜、铁和锌的方法,确定了最佳仪器工作条件和样品处理方法.在选择好的实验条件下.测定铜的特征浓度为0.006#g/mL/1%吸收;铁的特征浓度为0.015μg/mL/1%吸收;锌的特征浓度为0.0031μg/mL/1%吸收.回收率分别为铜97.5%-98.0%,铁99.1%-100.2%,锌97.4%-99.1%.     

Hamilton's equations for constrained dynamical systems

We derive expressions for the conjugate momenta and the Hamiltonian for classical dynamical systems subject to holonomic constraints. We give an algorithm for correcting deviations of the constraints arising in numerical solution of the equations of motion. We obtain an explicit expression for the momentum integral for constrained systems.     

Ground State and Single Vortex for Bose-Einstein Condensates in Anisotropic Traps

For Bose-Einstein condensation of neutral atoms in anisotropic traps at zero temperature, we present simple analytical methods for computing the properties of ground state and single vortex of Bose-Einstein condensates, and compare those results to extensive numerical simulations. The critical angular velocity for production of vortices is calculated for both positive and negative scattering lengths a, and find an analytical expression for the large-N limit of the vortex critical angular velocity for a 〉0, and the critical number for condensate population approaches the point of collapse for a 〈 0, by using approximate variational method.     

Critical coupling and coherent perfect absorption for ranges of energies due to a complex gain and loss symmetric system

We consider a non-Hermitian medium with a gain and loss symmetric, exponentially damped potential distribution to demonstrate different scattering features analytically. The condition for critical coupling (CC) for unidirectional wave and coherent perfect absorption (CPA) for bidirectional waves are obtained analytically for this system. The energy points at which total absorption occurs are shown to be the spectral singular points for the time reversed system. The possible energies at which CC occurs for left and right incidence are different. We further obtain periodic intervals with increasing periodicity of energy for CC and CPA to occur in this system.     

Some Observations about the MOLSCAT

For calculation of cross sections for collisional transitions between rotational levels in a molecule, a computer code, MOLSCAT is available. For the transitions between rotational levels in H₂CS due to collisions with He atom, we have calculated cross sections under the CS approximation, for example, for total energy 11 cm^-1. The calculations have been done for the single energy 11 cm^-1 and for ten combinations. We have found that the cross sections for the single energy 11 cm^-1, differ from those in the first seven combinations, but are in agreement with those in the last three combinations. The reason for the difference in the results appears that the MOLSCAT uses the intermediate data of calculations for one energy, in the calculations for other energies. The agreement with the last three combinations may be understood that when the energy of combination is in the decreasing trend, the cross sections for the first (common) energy are equal. It may be suggested to run the MOLSCAT for a single energy at a time.     

多能级原子系统暗压缩态的制备

基于二能级原子暗压缩态的制备方案，对多能级原子系统暗压缩态的产生机理进行研究，并提出一个如何在多能级原子系统中制备压缩态的方案。结果表明，在Lamb—Dicke近似下，考虑边带冷却效应就可以将多能级原子冷却至最低最子态；通过选择合适的入射光中心频率，利用多能级原子系统同样可以激光冷却被俘获的原子，并导致暗压缩态的出现。     

Systematics of inner-shell photo-ionization X-ray lasers with constant pump rates

Population-rate equations are analytically solved for constant pump rates. Conditions for population inversions are developed for this simplified case. Numbers appropriate for inner-shell photo-ionization of magnesium and neon are used. These allow back-of-the envelope calculations for predicting lasing duration. Pump-rate thresholds are also given which permit lasing for the duration of the pumping. Blackbody-source temperatures associated with such pump rates are calculated. A method of using the solution of the small-signal population-rate equations to determine the saturated intensity when the lower lasing level has a decay channel is given. This method is applied to the case of constant pump rates. An analytic expression for the saturated intensity is developed for this case.