英国兰开夏大学的物理实验教学

简要介绍了英国兰开夏大学的物理实验教学和成绩评定方法,分析了其特色,可以看出该大学较重视学生创造性综合能力的培养.     

理性、有序地建设探究实验室

建设探究实验室是提高学生对学习、学科兴趣的重要举措.本文提出了一套探究实验室评价方案以期对实验室的建设和发展有所帮助.总体评价和导向性评价基于对一个个实验就一些指标进行评估以及其后的统计.我们还对一些深层次的要求和指标进行了探讨.     

Generalized entropy optimization problems and the existence of their solutions

In the present study we have formulated a generalization of entropy optimization problems (GEOP), proposed sufficient conditions for the existence of solution. We have suggested also a new method based on a priori evaluations and Newton's methods for calculation of Langrange multipliers. Mentioned method allows calculating Langrange multipliers by starting from arbitrary initial point for Newton's approximations of constructed auxiliary equation. The solution of auxiliary equation is chosen as initial point for second constructed auxiliary equation. The recurring mentioned process for finite time leads to achieve an initial point for Newton's approximations of given equation and allows to find its unknown solution.     

Uncertainty evaluation of the spectral UV irradiance evaluated by using the UVSPEC radiative transfer model

The radiative transfer models allow calculating the spectral UV irradiance from some set of measured input quantities linked with the surface reflectivity, the solar zenith angle, the ozone column and the characteristics of clouds and aerosols. The spectral irradiance yielded by a model is influenced by errors in the measurement of the input quantities. In this paper, the influences of these errors are characterized and compared with other systematic effects through an uncertainty analysis. We evaluated the uncertainty of the spectral UV irradiance rendered by the UVSPEC model, under cloudless sky conditions. In order to express the uncertainty of the output quantities (the global, direct and diffuse irradiances) in terms of the standard uncertainties of the input quantities, we used a Monte Carlo-based uncertainty propagation technique. We found that the uncertainty of the irradiance in the UV-B part of the spectrum was strongly influenced by the uncertainty attributed to the ozone column datum. Moreover, the uncertainities associated with the aerosol parameters accounted for most of the UV-A global irradiance uncertainty; the latter increased from about 4% under low aerosol conditions, up to about 14% in case of polluted air. We conclude that the UV irradiance evaluation through radiative transfer models requires paying special attention to the assessment of the aerosols properties.     

Phase recovery from fringe patterns using the continuous wavelet transform

Interferometry is well established as an optical technique in which a measurand is encoded as the phase of a periodically varying intensity pattern. In view of the inherent accuracy of interferometry, many methods have been developed to retrieve the phase from images of the fringe pattern. Our focus in this paper is one such technique—the continuous wavelet transform (CWT). We begin by reviewing the CWT and the space–spatial–frequency localisation properties of wavelets. We show that a path which follows the maximum modulus of the CWT (the wavelet ridge) gives the instantaneous fringe frequency as a function of spatial displacement. The phase is automatically and trivially obtained, without discontinuities, by integration. Examples of practical wavelets are given and algorithms to isolate the wavelet ridge reviewed.     

NorTRACK product tracking system—development and implementation

This paper presents the experience gained by developers and users with implementation and operation of NorTRACK^TM, a real-time computerized product tracking system. A Programmable Logic Controller (PLC) collects and transfers data in real time to NorTRACK’s Oracle^TM database on a Windows NT^TM server network. After extensive development and Beta testing at MDS Nordion’s Canadian Irradiation Centre in Montreal, Canada, NorTRACK was installed in January 1997 with a new irradiation facility in Ethicon Endo-Surgery Inc.’s Albuquerque plant in the United States. NorTRACK communicates with the irradiator control and safety system, the plant's central manufacturing database, an innovative pallet staging and tote loading robot, and an automated dosimetry reading system. This integrated system allows the sterilization facility to monitor the irradiator operation and the flow of many products, through varied processing modes, continuously and reliably. As a result of operating with NorTRACK, both MDS Nordion’s CIC facility and the Endo-Surgery manufacturing site, are beginning to realize unique benefits in their respective operations. MDS Nordion is also initiating several future product enhancements and additional productivity modules. This paper describes the NorTRACK system, the various stages of the development project and Beta tests, and the experience of the users to date in their operations.     

线性规划中大M法的参数M估值问题

在线性规划的单纯形法中,为求初始的可行基有著名的大M法,即惩罚因子法.在通常的运筹学教材中,只说明当M充分大时,大M法是有效的,并没有给出参数M的确切估计值.现给出一个确定的常数M0,并证明当M>M0时,大M法收敛于原问题的最优解.     

Construction of triangular DP surface and its application

In this paper, a new type of bivariate basis on a triangle is presented, which is constructed by extending the univariate NTP basis proposed by Delgado and Peña. Some algebraic properties and its recursive formulae are given. Then a new type of surfaces that is called triangular DP surface is defined, and its recursive evaluation algorithm is obtained. Also, in the case of low degree, its subdivision algorithm and degree elevation algorithm are derived. It is shown that this type of surfaces is obviously more advantageous than triangular Bézier surface, and hence extremely useful for geometric design, especially for the situation in which the surface needs to be evaluated quickly.