用AE打造逼真的“文字流星雨”特效

电视片头和广告中经常看到出现下落的流星雨效果,它能够起到活跃气氛,加强节奏的作用.在此,我们用AE的Particle Playground制作这种效果,操作简单,无须任何插件.     

ATM交换集线器中FKO算法的效率改进

ＦＫＯ （Ｆａｓｔ Ｋｎｏｃｋｏｕｔ） 算法是用于由２ ×２ （ 二输入二输出） 排序元件构造多级级连自路由集线器的算法． 当ｍｔｏｎ 自路由集线器的输入端数ｍ 和输出端数ｎ 在实际应用范围内时，ＦＫＯ 是一种非常有效的技术．ＦＫＯ 算法中需用到一个配对的子算法， 选用不同的子算法就得到复杂性不同的集线器网络． 本文提出一个新的配对子算法可以得到覆盖所有实际应用范围的最好结果， 且新的配对子算法与原来存在的配对子算法相比在近２０ ％ 的个例中效率得到改进．     

FAST Gen发电机远程检测系统的应用

详细介绍了FAST Gen发电机远程检测系统的组成和功能特，董，以及在珠海发电厂2号机组检修中的应用情况，结果证明FAST Gen系统能够有效缩短检修工期，提高检修质量。     

The application of Fast Fourier Transform (FFT) method in the twin-channel system instability under ocean conditions

Parallel-channel two-phase flow systems under ocean conditions suffer from very serious parallel-channel instability, depending on the inherent characteristics of each channel and operating conditions. The influences of ocean conditions on the instability of parallel channel are very intensive. The trajectory of mass flow is very complex, sometimes even chaos occurs. The traditional methods cannot analyze such curves effectively. In this paper, Fast Fourier Transformation (FFT) method is used to analyze the complex curve of mass flow. Based on this method the oscillation curve can be decomposed. Some basic motions and inherent characteristics can be shown by the decomposition. The accurate analysis of the influence of ocean conditions can be achievable. The onset of inherent parallel-channel instability is also analyzed.     

快帧速双稳态胆甾相反射式液显示器

本文讨论快帧速双稳态胆甾相(BCT)反射式显示器的设计。从理论上研究由垂直态排列到平面排列转换的弛豫时间对亮度的影响。实验确定了帧频、隔行比和显示尺寸对亮度和对比度的影响，并提供了一些驱动波形的概貌。     

Reversal modes and reversal times in submicron sized elements for MRAM applications

The switching behavior of submicron sized NiFe nanoelements was calculated using a hybrid finite element/boundary element method. The numerical integration of the Gilbert equation of motion reveals the transient states during magnetization reversal under the influence of a constant applied field. The reversal mode and the reversal time sensitively depend on the size and the shape of the elements. The 200 × 100 × 10 nm³ elements switch well below 1 ns for an applied field of 80 kA/m and a Gilbert damping constant =0.1. The elements reverse by non-uniform rotation. If an external field is applied the magnetization starts to rotate near the ends, followed by the reversal of the center. This process requires only about 0.1 ns. In what follows, the magnetization component parallel to the field direction shows oscillations, which decay within a time of 0.4 ns. The excitation of spin waves is caused by the precession of the magnetization around the local effective field. A rapid decay of the oscillations is obtained in elements with slanted ends, where surface charges cause a transverse demagnetizing field.     

Fast H in hydrogen mixed gas microwave plasmas when an atomic hydrogen supporting surface was present

Atomic hydrogen is heated to temperatures of up to two orders of magnitude greater than the electron temperature or the temperature of any other species in certain hydrogen mixed gas RF or glow discharge plasmas. A crucial test of energetic hydrogen chemistry regarding a resonant energy transfer or rt-mechanism (RTM) versus field acceleration models (FAM) as the basis of this selective isotropic heating of a population of extraordinarily high-kinetic-energy hydrogen atoms is the observation of fast H in microwave cells proven to lack a high field as shown by the complete absence of fast H (∼0.08 eV) by Jovicevic et al. [S. Jovicevic, N. Sakan, M. Ivkovic, N. Konjevic, J. Appl. Phys. 105, 013306-1 (2009)]. The RTM predicts an enhancement in the production of fast H with the presence of a surface to support a high concentration of hydrogen atoms in order to initiate the energetic hot H source reaction that then propagates isotropically throughout the plasma. In contrast to the prior results, extraordinarily fast H of greater than 4 eV (50 times that observed and deemed possible in the Evenson microwave cell by FAM advocate Jovicevic et al.) and 50% fractional population was observed as predicted for RTM using the catalytic reaction systems of He/H₂, Ar/H₂, pure H₂, and water vapor microwave plasmas when an electrically insulating, but atomic hydrogen supporting material was placed in the plasma region. Increasing concentrations of Xe in the non-catalytic Xe/H₂ system results in a significant decrease in the energy and population of fast excited-state H atoms.     

Control of a dual stage magnetostrictive actuator and linear motor feed drive system

A dual stage feed drive system is well suited to satisfying current demands of high performance machining with tight position control under high feed rates in the presence of disturbances. It does this by integrating an actuator with high position resolution and fast response together with a conventional linear drive. A magnetostrictive actuator (MA) with a bandwidth in the kHz range capable of several kN of force output is an ideal candidate for use as the fine positioning element in such a dual stage system. However, MAs display significant hysteresis in their performance. This makes the effective implementation of real-time fast servo control challenging. In this paper, a dynamic Preisach model is utilized to reduce the undesired nonlinearity. A sliding mode controller (SMC) is designed to deal with uncertainties such as the Preisach modeling error as well as external disturbances so as to ensure a robust stable system. Experimental results show the servo performance improvement during a feed step test for single axis control and a single axis component of a sharp path interpolation test.     

Call admission and handoff control in multi-tier cellular networks: algorithms and analysis

In this paper, we investigate a call-admission and handoff-control framework for multi-tier cellular networks. We first propose and compare Call-Admission Control (CAC) algorithms based on the cell-dwelling time, by studying their impact on the handoff-call dropping and new-call blocking probabilities and the channel partitioning between the two tiers. Our results show that a simple, cell-dwelling-time-insensitive algorithm performs better under various mixes of user mobilities and call types. Moreover, there is an optimal channel partition of the overall spectrum between the tiers which minimizes the dropping and blocking probabilities for the two different CAC algorithms studied in this paper. Once the call is admitted into the network, we propose and compare various handoff- queuing strategies to reduce the call dropping probability. We show that implementing a queuing framework in one of the tiers (especially the upper, i.e., macrocellular, tier), results in a significant reduction in the dropping probability.