大断面结构参数计算机模拟研究

为了解决弓长岭井下在矿体倾角较大、下盘围岩不稳固的情况下矿石回收率低的问题,本文从弓长岭铁矿的实际应用出发,深入研究了放矿口对散体移动规律的影响,在分析模拟系统的设计要求及功能的基础上,对D.Jolley模型进行建模.采用C#开发了计算机模拟系统,模拟实现了大断面出矿的一系列过程。该系统能够对多种方案进行模拟,并对模拟结果进行选优。仿真结果表明大断面进路出矿对提高矿石回收率的正确性及有效性。     

Strain rate sensitivity of the commercial aluminum alloy AA5182-O

The mechanical behavior of the commercial aluminum alloy AA5182-O is investigated at temperatures ranging from −120 to 150 °C and strain rates from 10⁻⁶ to 10⁻¹ s⁻¹. The strain rate sensitivity parameter is determined as a function of temperature and plastic strain, and the strain rate and temperature range in which dynamic strain aging leads to negative strain rate sensitivity is mapped. The effect of dynamic strain aging on ductility and strain hardening is investigated. The sensitivity of the measured quantities to the experimental method employed and their dependence on grain shape are discussed. The experimental data are compared with the predictions of a model constructed based on a recently proposed mechanism for dynamic strain ageing. The mechanism is based on the effect solute clustering at forest dislocations has on the strength of dislocation junctions. The model is shown to reproduce qualitatively the experimental trends.     

A bending specimen for constant energy release rate under controlled displacement conditions

A bending specimen that gives a constant energy release rate (independent on the crack length) under controlled displacement conditions is developed. It is assumed that engineering beam theory is applicable, i.e. that among other things, small deformations and linear elastic isotropic material can be assumed.A specific geometry is analyzed numerically by use of the finite element method and experimentally by manufacturing a specimen with the actual geometry in PMMA (polymethylmetacrylate) and then determining the specimen stiffness for different crack lengths.It is found that the geometry considered gives a constant energy release rate under controlled displacement conditions.     

组合式空调系统设计中机组选型方法探讨

对目前组合式空调机组在选型设计及使用中出现的问题进行了分析，运用空气处理设备选型的有关理论和计算方法，对舒适性空调系统中机组选型的一些问题和数据进行了简化和近似处理，提出了能够满足工程设计的要求的简便实用的选型方法。     

钒球的中子倍增率与活化反应率

以一直径138cm的聚乙烯球作为中子慢化剂与全吸收探测器，采用全吸收法测量了钒球的14MeV中子的泄漏倍增率。用1支与H对热中子具有相同1／V吸收规律的^6Li玻璃探测器的测量子全吸收体的径向中子计数率分布。实验得到了钒球中心D－T中子时的Al、Fe、In和V一组阈探测器的绝对活化反应率的分布。用MCNP／4A程序、ENDF／B－Ⅵ和FENDL－2核数据进行了模拟计算。与实验结果相比较可知：用ENDF／B－Ⅵ库数据的计算结果与实验结果符合良好，而用FENDL－2库数据的计算结果比实验结果约高4％。     

SABUL: A Transport Protocol for Grid Computing

This paper describes SABUL, an application-level data transfer protocol for data-intensive applications over high bandwidth-delay product networks. SABUL is designed for reliability, high performance, fairness and stability. It uses UDP to transfer data and TCP to return control messages. A rate-based congestion control that tunes the inter-packet transmission time helps achieve both efficiency and fairness. In order to remove the fairness bias between flows with different network delays, SABUL adjusts its sending rate at uniform intervals, instead of at intervals determined by round trip time. This protocol has demonstrated its efficiency and fairness in both experimental and practical applications. SABUL has been implemented as an open source C++ library, which has been successfully used in several Grid computing applications.     

Classification of heart rate data using artificial neural network and fuzzy equivalence relation

The electrocardiogram is a representative signal containing information about the condition of the heart. The shape and size of the P-QRS-T wave, the time intervals between its various peaks, etc. may contain useful information about the nature of disease afflicting the heart. However, these subtle details cannot be directly monitored by the human observer. Besides, since bio-signals are highly subjective, the symptoms may appear at random in the time scale. Therefore, the signal parameters, extracted and analysed using computers, are highly useful in diagnostics. This paper deals with the classification of certain diseases using artificial neural network (ANN) and fuzzy equivalence relations. The heart rate variability is used as the base signal from which certain parameters are extracted and presented to the ANN for classification. The same data is also used for fuzzy equivalence classifier. The feedforward architecture ANN classifier is seen to be correct in about 85% of the test cases, and the fuzzy classifier yields correct classification in over 90% of the cases.     

Stochastic stabilization of differential systems with general decay rate

Some sufficient conditions concerning stability of solutions of stochastic differential evolution equations with general decay rate are first proved. Then, these results are interpreted as suitable stabilization ones for deterministic and stochastic systems. Also, they permit us to construct appropriate linear stabilizers in some particular situations.     

千兆比特以太网结构化布线要求

本文就目前人们较为关注的千兆比特以太网进行了简要的介绍，并较为详细地说明了千兆比特以太网所需的布线系统和结构化布线的要求。     

Knowledge-directed Adaptation in Multi-level Agents

Most work on adaptive agents have a simple, single layerarchitecture. However, most agent architectures support three levels ofknowledge and control: a reflex level for reactive responses, a deliberatelevel for goal-driven behavior, and a reflective layer for deliberateplanning and problem decomposition. In this paper we explore agentsimplemented in Soar that behave and learn at the deliberate and reflectivelevels. These levels enhance not only behavior, but also adaptation. Theagents use a combination of analytic and empirical learning, drawing from avariety of sources of knowledge to adapt to their environment. We hypothesize that complete, adaptive agents must be able to learn across all three levels.