The potential for energy efficiency in electric end usetechnologies

The authors summarize a recent study conducted by the Electric Power research Institute (EPRI) that contains estimates of potential energy savings that will result if the most efficient electricity technologies readily available immediately attain complete market saturation in the year 2000. They first define and contrast various efficiency scenarios and then summarize the energy savings forecast associated with demand-side management measured by sector. These estimates have been developed through discussions with a wide range of experts both inside and outside the utility industry, review of the trade and technical literature, and simulations and forecasts using several end-use models. The main results for efficient technologies that reduce electric usage are presented     

Automated derivation of time bounds in uniprocessor concurrentsystems

The successful development of complex real-time systems depends on analysis techniques that can accurately assess the timing properties of those systems. This paper describes a technique for deriving upper and lower bounds on the time that can elapse between two given events in an execution of a concurrent software system running on a single processor under arbitrary scheduling. The technique involves generating linear inequalities expressing conditions that must be satisfied by all executions of such a system and using integer programming methods to find appropriate solutions to the inequalities. The technique does not require construction of the state space of the system and its feasibility has been demonstrated by using an extended version of the constrained expression toolset to analyze the timing properties of some concurrent systems with very large state spaces     

Invasiveness of LiTaO/sub 3/ and GaAs probes in external E-O sampling

Disturbances of signals on a coplanar waveguide (CPW) induced by the presence of LiTaO/sub 3/ and GaAs electrooptic probes in external electrooptic (EO) sampling have been simulated and compared quantitatively. The finite-difference-time-domain method is used to simulate the full wave field around a coplanar waveguide on a GaAs substrate in an external EO sampling configuration. The results indicate that the induced signal disturbance, or invasiveness, of a LiTaO/sub 3/ probe is almost ten times that of a GaAs probe in terms of the magnitude of S/sub 11/, but that LiTaO/sub 3/ yields about two times the EO response for a given S/sub 11/ and optical probing wavelength. The transparency of LiTaO/sub 3/ to shorter wavelengths, however, allows an even higher sensitivity for this material relative to GaAs. The results suggest that these probes do not exhibit significant invasiveness (magnitude of S/sub 11/ smaller than -40 dB), if they are removed from contact by the distance of CPWs center conductor width.<>     

智能化红外焊缝检测仪的实时信号自相关分析

详细介绍了在改进红外焊缝检测仪的过程中实时信号的一种抗干扰方法－－自相关方法。重点离自相关方法的数学模型，软件框图及设计思想，并给出了实验结果。     

基于逻辑器件的可编程增益放大器设计

本文介绍了可编程增益放大器设计的方法。它主要由控制电路、放大电路、显示电路三大模块组成。该系统性能好、成本低、工作可靠,具有一定的工程应用价值,经测试表明,该设计基本上达到了设计的要求。     

Multiregional estimation of gross internal migration flows

"A multiregional model of gross internal migration flows is presented in this article. The interdependence of economic factors across all regions is recognized by imposing a non-stochastic adding-up constraint that requires total inmigration to equal total outmigration in each time period. An iterated system estimation technique is used to obtain asymptotically consistent and efficient parameter estimates. The model is estimated for gross migration flows among the Canadian provinces over the period 1962-86 and then is used to examine the likelihood of a wash-out effect in net migration models. The results indicate that previous approaches that use net migration equations may not always be empirically justified."     

Updated Characteristics of Torrential Pools

Power Technology and Engineering - Advanced methods for determining the hydrological and geomorphological characteristics of torrential pools, which are important for the design of reliable and...     

Differentiation of hydroxyproline isomers and isobars in peptides by tandem mass spectrometry

The isomeric 3- and 4-hydroxyprolines are isobaric with the isomers leucine and isoleucine, and all four have, therefore, the same "residue mass" of 113. Secondary fragmentation processes were found that differentiate the hydroxyproline isomers from each other and from the leucines. Variants of synthetic bradykinin containing one or two hydroxyproline moieties were prepared by using manual Edman degradation and/or enzymatic methods. The tandem mass spectra of these peptides were recorded. The C-terminal wn fragment ions allow the differentiation of 4-hydroxyproline from the 3-isomer and isoleucine, while the N-terminal an ions containing 4-hydroxyproline undergo H2O elimination to differentiate this amino acid from the 3-isomer and leucine. Lys-C digestion of a mussel adhesive protein produced a set of decapeptides varying in the degree of hydroxylation of proline and tyrosine. Heterogeneity with respect to 3-hydroxyproline and 4-hydroxyproline at a certain position in these peptides was assessed by tandem mass spectrometry based on the wn ion series in the CID spectra of these Lys-C peptides. Some N-terminal ions further allow for the differentiation of these two isomeric species.     

Crack tip parameters and elastic-plastic fracture of metals

By using optical displacement-measuring techniques we obtain the crack tip fields in terms of crack tip strain, crack opening angle (COA) and crack tip opening angle (CTOA). Thin plates with different crack configurations made of six elastic-plastic materials with strain hardening exponent ranging from 3 to are studied. We find that the COA resistance curve assumes certain characteristics common to all the materials. The experimental results indicate that the critical value of COA may be used as a fracture toughness parameter for these materials.

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Résumé En utilisant une technique de mesure optique des déplacements, on obtient les champs régnant à l'estrémité d'une entaille, qui s'experiment par la déformation d'extrémité d'entaille, l'angle d'ouverture de la crique (COA et l'angle d'ouverture de la pointe de la crique (CTOA). On étudie des feuillards présentant différentes configurations de fissures et réalisés en six matériaux élasto-plastiques dont les modules d'écrouissage s'échelonnent de 3 à l'infini.On trouve que la courbe de résistance COA suppose certaines caractéristiques communes à tous les matériaux. Les résultats expérimentaux indiquent que la valeur critique du COA peut être utilisée comme paramètre de ténacité à la rupture pour les matériaux étudiés.