Effect of Additives on Magnetic Properties of High Frequency MnZn Power Ferrite

In keeping with the advance of more compact and more power-saving electronic equipment, the demand is increasing for smaller and more efficient switching power supply. Therefore, it is necessary to provide the adequate magnetic power ferrite materials to satisfy the demand. Such ferrite materials have to meet the following main requirement: 1) high initial permeability (μ i ); 2) high saturation magnetic induction (Bs); 3) high Curie temperature (Tc); 4) high electrical resistivity (ρ ); 5)…     

预测控制算法的统一格式及其在电加热炉的应用

本文根据常用的两类预测控制算法推出一种新型预测控制算法。并将其应用于一双输入/双输出的力学持久机电加热炉的温度控制系统上,获得了满意的结果:控温精度为±1.5℃/300℃,且适用于非最小相位系统。     

毫米波连续波雷达载波泄漏对消——理论分析与系统仿真

对限制连续波体制雷达系统作用距离的载波泄漏问题仔细地作了探讨，对各种连续波体制载波泄漏有源对消方法进行了理论分析，并针对毫米波宽带调频雷达实际泄漏信号的特点进行了对消环路的系统仿真。结果表明设计良好的对消系统能有效地抵消载波泄漏功率达３０￣６０ｄＢ，对进一步作实验研究提供了理论基础。     

On the algebraic formulation of certain geometry statements and mechanical geometry theorem proving

In this paper we analyze the algebraic formulations of certain geometry statements appearing in recent literature related to mechanical geometry theorem proving and give several examples to show that one of these formulations can cause serious problems. We clarify a formulation which is essentially due to W. T. Wu and, in our opinion, is the most satisfactory.This author was supported by NSF Grants DCR-8503498 and CCR-8702108.     

岩金矿山空区处理研究

文章阐述了岩金矿山空区处理研究的手段及空区处理的方法，探讨了空区破坏的地质，力学机理。     

我国核裂变能可持续发展战略研究

本文从科学技术的角度,分析我国国民经济增长对核能发展的需求,探讨我国核能的近中期发展战略构想,指出为实现其发展战略目标而应重点研究的关键科学技术与问题,并提出一些相关的政策建议,为国家制定核能中长期发展规划提供参考。     

封闭式差动轮系的功率分流和力分流

对封闭式差动轮系进行了受力分析，揭示了封闭系统所起的作用以及轮系中的功率分流和力分流的现象．     

A new algorithm for fast mining frequent itemsets using N-lists

Mining frequent itemsets has emerged as a fundamental problem in data mining and plays an essential role in many important data mining tasks.In this paper,we propose a novel vertical data representation called N-list,which originates from an FP-tree-like coding prefix tree called PPC-tree that stores crucial information about frequent itemsets.Based on the N-list data structure,we develop an efficient mining algorithm,PrePost,for mining all frequent itemsets.Efficiency of PrePost is achieved by the following three reasons.First,N-list is compact since transactions with common prefixes share the same nodes of the PPC-tree.Second,the counting of itemsets’ supports is transformed into the intersection of N-lists and the complexity of intersecting two N-lists can be reduced to O(m + n) by an efficient strategy,where m and n are the cardinalities of the two N-lists respectively.Third,PrePost can directly find frequent itemsets without generating candidate itemsets in some cases by making use of the single path property of N-list.We have experimentally evaluated PrePost against four state-of-the-art algorithms for mining frequent itemsets on a variety of real and synthetic datasets.The experimental results show that the PrePost algorithm is the fastest in most cases.Even though the algorithm consumes more memory when the datasets are sparse,it is still the fastest one.     

闭式叶盘叶身加工切触点规划算法研究与实现

闭式整体叶盘是现代高推重比航空发动机采用的新结构。在对闭式整体叶盘叶身造型方法分析的基础上，提出基于叶片防扭曲高质量造型的等误差切触点规划算法，详细描述了算法中边界参数点确定、切削行参数划分、走刀步长确定和型值点网格化四个步骤，给出了该算法的在UGCAD系统中的实现及工程应用实例。实践证明，该算法可以保证加工质量、提高加工效率、节省系统资源，具有较强的工程实践意义。     

两相闭式热虹吸管冷凝换热规律的实验研究

本文通过可视化热虹吸管实验,拍摄了冷凝段内部冷凝液的各种基本流型和特殊流型,设计了试验用多节风冷热虹吸管以及相应的风道系统。采用自行组装的高精度微机控制的测试系统测量温度,对不同工质(水、乙醇、丙酮、氟里昂-11)热虹吸管进行了不同工况的实验。获得了各种工程实际工况下的冷凝换热系数,还获得了冷凝换热系数随热流密度、蒸汽压力变化的规律以及沿2.5米长冷凝面长度上的变化规律。实验结果表明,热虹吸管的冷凝换热系数在很大范围内偏离努塞尔特理论解。本文结合可视化实验,对其进行了分析。