电话机免提通话集成电路的特点及常见故障的分析

在比较电话机免提通话集成电路特点的同时,分析了MC34018集成电路的内部工作原理及其常见故障,并优化了与集成块TEA1062共同组成的免提电路的工作流程.     

硅二极管I-V特性及二次击穿计算

利用时域有限差分方法 ,求解了一维半导体器件内部载流子所满足的耦合、非线性、刚性偏微分方程组。得出了发生二次击穿的判据应以空穴电离率为准 ,而不是通常认为的以电子电离率为准的结论 ,并构造了一种准确、快捷地计算半导体器件反偏I-V特性曲线的方法。     

Determination of the major elements in homogeneous and heterogeneous samples by tandem laser-induced breakdown spectroscopy-partial least square regression

The tandem laser-induced breakdown spectroscopy-partial least square regression (LIBS-PLS) was applied for the analysis of both, a smelting product from a noble metal ore (as example of a homogeneous sample) and a calcareous rock from a Maya building (as a heterogeneous sample). The method was designed for the analysis of both samples without perceptible deterioration of the pieces, by monitoring the emission lines of the major elements present in each sample while subjecting the pieces to a number of laser shots. The results obtained, as well as the precision provided by the LIBS-PLS method, were statistically compared with those obtained by graphite furnace-atomic absorption spectroscopy (for Ag and Cu) and flame atomic emission spectroscopy (for Ca), showing good agreement between methods.     

Morphology and Fine Structure of Membranes upon Osmotic Upshifts

Lipid bilayers are impermeable to most polar molecules. Osmoregulated transporters are responsible for controlling the intracellular osmolarity and protecting the cell against changes in osmolality in the environment. The mechanisms by which membranes regulate the activity of these transporters are still largely unknown. In this paper we investigate the response to hyperosmotic stress in artificial, chemically well-defined membrane models called Giant Unilamellar Vesicles (GUV). The lipid compositions analysed are relevant for the activity of an ABC-transport system that is controlled by the physicochemical properties of the membrane bilayer. Morphology changes are monitored by phase-contrast optical microscopy, and fine structural details related to domain formation are investigated by fluorescence confocal optical microscopy.     

Mechanical and optical properties of silver-halide infrared transmitting fibers

This article presents a review of the optical and mechanical properties of infrared transmitting fibers extruded from single crystals of silver-halides at the Applied Physics Group in Tel-Aviv University during the last decade. The optical properties of Agcl_xBr_1-x crystals and fibers include the spectral transmission window, laser power transmission, the change of the power distribution traveling along the fiber, and the laser-induced breakdown. The mechanical properties include the investigation of the ultimate tensile strength (UTS), hardness, and the elastic strain limits of these fibers and their composition dependence. The mechanical properties that involve single and multiple bending of fibers in the plastic and the elastic strain limits are also described.     

Complex networks: Dynamics and security

This paper presents a perspective in the study of complex networks by focusing on how dynamics may affect network security under attacks. In particular, we review two related problems: attack-induced cascading breakdown and range-based attacks on links. A cascade in a network means the failure of a substantial fraction of the entire network in a cascading manner, which can be induced by the failure of or attacks on only a few nodes. These have been reported for the internet and for the power grid (e.g., the August 10, 1996 failure of the western United States power grid). We study a mechanism for cascades in complex networks by constructing a model incorporating the flows of information and physical quantities in the network. Using this model we can also show that the cascading phenomenon can be understood as a phase transition in terms of the key parameter characterizing the node capacity. For a parameter value below the phase-transition point, cascading failures can cause the network to disintegrate almost entirely. We will show how to obtain a theoretical estimate for the phase-transition point. The second problem is motivated by the fact that most existing works on the security of complex networks consider attacks on nodes rather than on links. We address attacks on links. Our investigation leads to the finding that many scale-free networks are more sensitive to attacks on short-range than on long-range links. Considering that the small-world phenomenon in complex networks has been identified as being due to the presence of long-range links, i.e., links connecting nodes that would otherwise be separated by a long node-to-node distance, our result, besides its importance concerning network efficiency and security, has the striking implication that the small-world property of scale-free networks is mainly due to short-range links.     

Laser-induced breakdown spectra of Zn2 molecule in the violet region

Laser-induced breakdown spectrum has been recorded in the region of 380–455 nm using second harmonics of Nd:YAG laser, computer-controlled TRIAX 320 M monochromator with a reciprocal linear dispersion 2.64 nm/mm fitted with ICCD detector. The spectrum consists of 108 bands, which are classified into four new subsystems E0 _u ⁺ (¹Σ _u ⁺ ) → A1_g(³Π_g), J0 _g ^± \1_g(³Σ _g ⁺ ) → D1_u(¹Π_u), F1_u → A0 _g ^± (³Π_g) and F1_u → A2_g(³Π_g) along with additional bands of the known system E0 _u ⁺ (¹Σ _u ⁺ ) → A0 _g ^± (³Π_g). The molecular constants for these systems have also been determined.     

电容容量降低对电视机的影响分析

电容容量的降低会引起电视机开关电源不能正常工作，还会造成图像效果变差或伴音失真的故障，在解码电路中电容容量的降低会产生无彩色等现象，调制级接地时回扫线布满屏幕也多是由电容容量下降引发。     

工程机械发动机水温过高故障的分析及排除

工程机械施工功率大、负荷重、工况复杂,水温过高是常见的故障之一。以作者在老挝万象市2号路的施工实践为例,对工程机械发动机水温过高故障进行了系统的分析,并总结出如何及时准确地发现故障和有效排除的方法。