电渣炉冶炼控制方式对比研究

介绍了电渣炉冶炼的两种控制方式,即功率控制和熔速控制。对此两种冶炼控制方式进行了对比研究。通过工艺稳定性试验,对其优缺点进行分析,并确定最优的电渣炉冶炼方式。     

Comparison of diffusion calculations for two models of powder mixtures

Summary The advantages and drawbacks are discussed of two models of powder mixtures: The model based on single-particle approximation and the concentric sphere model. Calculated values obtained by using both models are compared with experimental data.Translated from Poroshkovaya Metallurgiya, No. 1, pp. 23–24, January, 1968.     

Context effects in letter perception: Comparison of two theories.

This study showed that Elementary Perceiver and Memorizer (EPAM) can explain letter recognition phenomena earlier simulated by the connectionist Interactive Activation Model (IAM) of word perception by J. L. McClelland and D. E. Rumelhart (see record 1981-31825-001) and Rumelhart and McClelland (see record 1982-07091-001). EPAM, a model of learning and recognition in the form of a computer program, has previously successfully explained many aspects of learning and perception in a range of task environments (E. A. Feigenbaum and H. A. Simon, 1962). This study shows that the human data modeled by the IAM are at least as accurately simulated by EPAM. The fact that one model (EPAM) processes perceptions serially and the other (IAM) processes them in parallel plays no essential role in producing the observed context effects. Both connectionist and serial symbolic simulations can be designed to exhibit these effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of finite-difference transport and diffusion calculations for photon migration in homogeneous and heterogeneous tissues

We analyse the limits of the diffusion approximation to the time-independent equation of radiative transfer for homogeneous and heterogeneous biological media. Analytical calculations and finite-difference simulations based on diffusion theory are compared with discrete-ordinate, finite-difference transport calculations. The influence of the ratio of absorption and transport scattering coefficient (mu(a)/mu'(s)) on the accuracy of the diffusion approximation are quantified and different definitions for the diffusion coefficient, D, are discussed. We also address effects caused by void-like heterogeneities in which absorption and scattering are very small compared with the surrounding medium. Based on results for simple homogeneous and heterogeneous systems, we analyse diffusion and transport calculation of light propagation in the human brain. For these simulations we convert density maps obtained from magnetic resonance imaging (MRI) to optical-parameter maps (mu(a) and mu'(s)) of the brain. We show that diffusion theory fails to describe accurately light propagation in highly absorbing regions, such as haematoma, and void-like spaces, such as the ventricles and the subarachnoid space.     

Comparison of an asymmetric screen-film combination with a conventional screen-film combination for chest radiography in 51 patients

Comparison is made between a new asymmetric screen-film combination and a conventional screen-film combination for use in chest radiography. Seven anatomical features were assessed by three consultant radiologists in each of 51 film pairs. A preference was indicated if one system better demonstrated a particular feature. Alternatively, no preference was indicated if the feature was equally demonstrated by both systems or not demonstrated at all. Any pathology incidentally noted which remained unchanged between the two films was localized to lung, mediastinum or bone and marked in the same way. The asymmetric high contrast system scored higher than the conventional system for demonstration of anatomy in both mediastinum and lungs, but no difference emerged between the two systems in the demonstration of pathology. The asymmetric screen-film system showed improved mediastinal and, to a lesser degree, improved lung detail. Further assessment in necessary to define any associated improvement in diagnostic yield.     

电渣炉冷却水系统的发展

本文从冷却水系统的水量、水质、水温等几个方面分析了其对设备使用寿命和钢锭凝固质量的影响,并对国内外几种电渣炉循环水系统形式进行了比较,得出带热交换器的双重冷却水系统是目前最为科学的,此种冷却水系统可以保证设备使用寿命和钢锭的凝固质量.