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31.
基于面向对象技术的多媒体CAI素材库系统 总被引:1,自引:0,他引:1
建立实用、高效的多媒体CAI素材库是高效率、高质量开发CAI软件的基础和关键.本文从数据模型、面向对象分析和存储模式三方面入手,提出一种支撑CAI制作工具的素材库体系结构,并讨论该体系结构的特性和进一步研究的问题. 相似文献
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The prediction of infrared spectral radiance from high temperature media such as combustion gases requires spectroscopic data for triatomic molecules like water vapor and carbone dioxyde. At temperature above 2000 K, water vapor spectrum is composed of hundreds of thousands lines making practical computations uneasy. We have set up a spectroscopic database for water vapor, based on three existing lines compilations. This database is well suited to computation of remote sensing spectra where hot gases emission is seen through atmospheric paths. The database enables efficient computation of water vapor spectra between 600 and 6600 cm−1 at moderate spectral resolution (5 cm−1). It has been used to compute parameters of a statistical narrow band model which are used in practical applications. 相似文献
34.
Sieck L. Wayne Heron John T. Green David S. 《Plasma Chemistry and Plasma Processing》2000,20(2):235-258
Reliable kinetic and thermodynamic data are required to model the evolution of electric discharge or electron-beam decomposition chemistry of gases in humid air streams. In this first segment of a continuing series, we provide a core database describing the initially dominant ion-neutral molecule reactions in humid air plasmas. Recommended reaction rate data and extrapolation tools are presented in a manner to facilitate prediction of reactivities and reaction channels as a function of temperature, pressure, and applied electric field. 相似文献
35.
A stochastic model is developed describing a service system subject to inhomogeneous Poisson interruptions with age dependent interruption periods. By studying the probabilistic flow of the underlying multivariate Markov process, the Laplace transform of the effective service time is explicitly obtained. For general renewal interruptions, only the expected effective service time is derived. As an application, an optimal checkpoint policy is examined for database management. It is shown that an optimal policy maximizing the ergodic availability of the database is to implement a checkpoint as soon as the cumulative uptime of the database reaches a prespecified constantk
*. A computational procedure is then developed for findingk
* and numerical results are exhibited.This work was supported in part by the National Science Foundation under Grant No. ECS-8600992 and by the IBM Program of Support for Education in the Management of Information Systems. 相似文献
36.
Multifarious injection chamber for molecular structure study (MICOSS) system: development and application for serial femtosecond crystallography at Pohang Accelerator Laboratory X‐ray Free‐Electron Laser 下载免费PDF全文
Jaehyun Park Seonghan Kim Sangsoo Kim Ki Hyun Nam 《Journal of synchrotron radiation》2018,25(2):323-328
The multifarious injection chamber for molecular structure study (MICOSS) experimental system has been developed at the Pohang Accelerator Laboratory X‐ray Free‐Electron Laser for conducting serial femtosecond crystallography. This system comprises several instruments such as a dedicated sample chamber, sample injectors, sample environment diagnostic system and detector stage for convenient distance manipulation. Serial femtosecond crystallography experiments of lysozyme crystals have been conducted successfully. The diffraction peaks have reached to ~1.8 Å resolution at the photon energy of 9.785 keV. 相似文献
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David P. Kratz 《Journal of Quantitative Spectroscopy & Radiative Transfer》2008,109(6):1060-1080
Over the last quarter century, improvements in the determination of the spectroscopic characteristics of the infrared-active trace species have enhanced our ability to retrieve quantitative distributions of temperatures, clouds, and abundances for various trace species within the Earth's atmosphere. These improvements have also allowed for refinements in the estimates of climatic effects attributed to changes in the Earth's atmospheric composition. Modeling efforts, however, have frequently experienced significant delays in assimilating improved spectroscopic information. Such is the case for highly parameterized models, where considerable effort is typically required to incorporate any revisions. Thus, a line-by-line radiative transfer model has been used to investigate the magnitude of the effects resulting from modifications to the spectroscopic information. Calculations from this line-by-line model have demonstrated that recent modifications to the HITRAN (High Resolution Transmission) line parameters, the continuum formulation, and the CO2 line-mixing formulation can significantly affect the interpretation of the high spectral resolution radiance and brightness temperature retrievals. For certain moderate-resolution satellite remote sensing channels, modifications to these spectroscopic parameters and formulations have shown the capacity to induce changes in the calculated radiances equivalent to brightness temperature differences of 1-2 K. Model calculations have further shown that modifications of the spectroscopic characteristics tend to have a modest effect on the determination of spectrally integrated radiances, fluxes, and radiative forcing estimates, with the largest differences being of order 1 W m−2 for the total thermal infrared fluxes, and of order 2-3% of the calculated radiative forcing at the tropopause attributed to the combined doubling of CO2, N2O, and CH4. The results from this investigation are intended to function as a guide to differentiate between cases where older parameterizations provide acceptable results, within specified accuracy bounds, and cases where upgrades to the latest spectroscopic database are necessary. 相似文献
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Amidines, due to their unique biocompatibility and desirable physical characteristics, have been the functionality of choice as a scaffold for large number of drug synthesis. But still synthesis of amidines in the presence of other active functional groups or pharmacophore, remained a challenge. In this work, a simple and reliable protocol for conversion of nitrile-amide to unsubstituted amidine–amide is developed using metal amide and/or ammonia gas. The scope and efficiency of this synthetic strategy are demonstrated on several substrates which differ in functional groups will be discussed. In this process, 10 novel aryl amidines in good yields (upto 85%) were synthesized. Biological evaluation revealed that compound 4-(aminoiminomethyl)-N-(2-furanyl methyl) benzamide (IC50?=?9?µM) and 4-(aminoiminomethyl)-N-(3-pyridinylmethyl) benzamide (73.36% growth inhibition) showed moderate efficacy for cancer cells. 相似文献