Extended application of the complex source-point theory

In this paper, the complex source-point theory used for a symmetric concave spherical resonator is extended to an asymmetric concave spherical resonator. Thus, the formulae for the field distribution of the asymmetric spherical resonator can be easily deduced from the formulae for the field distribution of the symmetric resonator, thereby the application range of the complex source-point theory is enlarged and a convenient method is provided for the field analysis of an arbitrary spherical resonator.     

CAD OF MILLIMETER WAVE OSCILLATORS WITH THE FDHB TECHNIQUE

In this paper the modelling, analysis and optimization of millimeter wave oscillatorsare investigated by using the a frequency-domain harmonic balance technique (FDHB), where theexternal-circuit impedances looking outside from the active device are calculated with a combinedtechnique of modes expansion, Galerkin, and collocation methods. The optimization results arein agreement with the experimental ones, which show the reliability of the presented model andoptimization.     

A new kind of compound solid-state quasi-optical power combiner

In this paper, a new kind of solid-state quasi-optical power combiner is presented. It consists of two or more singlecavity multiple-device power combiners and a Fabry-Perot cavity. The experimenal results using six Gunn diodes at X-band show that the total output power is higher than 400 mW, the total combining efficiency is as high as 83%, and the frequency stability is better than 10^?5.     

Finite element analysis of local damage and post-failure behavior for strain-softening solid

A finite element analysis of the viscoplastic-softening model with the evolution of local damage for strain softening material is presented. An effective damage matrix is introduced to consider the influence of isotropic damage on different types of micro-cracking by different states of stress. The localized strain mode with local damage occurs in the post-failure regime of deformation. The computational techniques for tracing the post-failure path of the softening response are discussed with several examples.     

真空微电子三极管几何参数的设计考虑

真空微电子三极管是近年来兴起与发展的真空微电子学中的一类重要器件。本文从真空微三极管的工作特性出发,分析了这类器件中所需考虑的几何参数和工作特性的关系,并给出了一些理论和实验公式,为今后的设计提供一些参考。     

Compressive and tribological properties of Al2O3 fibre and hexagonal BN particle hybrid reinforced Al-Si alloys

Al₂O₃ fibre-hexagonal BN particle hybrid reinforced aluminium-silicon alloys were fabricated by centrifugal force infiltration route. Hardness test and ultimate compressive test results are reported. The wear and friction properties of hybrid MMCs was investigated by means of a block-on-ring (bearing steel) type wear rig in a dry sliding condition. It is shown that the hardness and ultimate compressive strength of hybrid MMCs was evidently decreased with the addition of hexagonal BN particles, however, the wear rate and coefficient of friction of hybrid MMCs was improved simultaneously with increase of BN particle volume fraction, especially for the higher applied loads in the test.     

一个捕食模型的反应扩散方程组解的动力学性质

研究了一个带有齐次Neumann边界条件的捕食模型的反应扩散方程组的初边值问题解的动力学性质.首先利用常微分方程解的渐近性质和偏微分方程的比较原理,讨论半平凡的常数平衡解[λ/a,0]的全局渐近稳定性,其次利用Lyapunov泛函方法讨论正的常数平衡解(■,■)的全局渐近稳定性.     

ROP防御研究现状

自从ROP思想被提出以来,对程序安全的影响,特别是当前已知的安全防御提出了新的挑战。最近几年,ROP的研究取得一些进展。如何去防御这种基于控制流的细粒度,而灵巧的攻击思想已成为当前ROP研究的一个重要方向。而ROP的最终防御的解决方案能够有效处理当前多数基于控制流攻击的防御问题,能够根除很多现行的控制流程序。因而,ROP的研究对于提升程序乃至体系结构的安全有着特别的意义。将阐述ROP的研究现状,指出ROP防御研究的当前瓶颈,并对ROP防御当前的瓶颈提出一些设想和解决方案。     

学龄前儿童教育类APP交互设计研究

目的探讨学龄前儿童教育类APP设计原则及实践,为基于移动应用的学龄前儿童教育软件交互设计提出方法论指导。方法从国内外学龄前儿童教育类APP交互设计研究现状分析入手,根据学龄前儿童生理与心理特征表现,提出学龄前儿童教育类APP交互设计原则,并将所提出的原则在实践中进行运用检验。结论定义了学龄前儿童教育类APP交互设计原则,并通过具体案例设计,初步验证了所做研究的适用性,使学龄前儿童与APP之间的交互体验契合学龄前儿童成长发育的特征。     

超临界直流锅炉蒸汽发生器的建模与仿真研究(一)

以某６００ＭＷ机组超临界直流锅炉的研究对象,建立了适用于大扰动全工况仿真的非线性集总参数移动边界的蒸汽发生器动态数学模型,解决了亚临界＝超临界以及水冷壁出口蒸汽为干态＝湿态的模型切换问题,对各个集总环节的代表参数的选取问题进行了研究,并提出采用最大比热点的工况作用为超临界压力下划分汽水区域的标准,采用了合理的二次建模方法,使模型方程组右端函数中不存在导数项,提高了数值积分的稳定性。