Cogging Torque Characteristics of a Magnetic‐Geared Motor

This paper describes the cogging torque characteristics of a magnetic‐geared motor with permanent magnets only on the high‐speed rotor. The operational principle, which is different from that of the magnetic‐geared motor with permanent magnets on the high‐speed rotor and stator, is described. The torque characteristics, especially the order of the cogging torque, are mathematically formulated and verified by conducting 3D finite element analysis and carrying out measurements on a prototype. A novel cogging torque reduction method is proposed and verified as well.     

异步计数器的一种设计方法

本文讨论了N进制异步计数器的一种快速设计法.这种方法对任意进制异步计数器的设计,特别是在模数N很大时,具有非常简便的优点.文中给出设计实例.     

State‐space µ analysis for an experimental drive‐by‐wire vehicle

This paper considers the application of the skewed structured singular value to the robust stability of systems subject to strictly real parametric uncertainty. Three state‐space formulations that counteract the discontinuous nature of this problem are detailed. It is shown that the calculation of the supremum of the structured singular value over a frequency range using these formulations transforms into a single skewed structured singular value calculation. Similar to the structured singular value, the exact calculation of the skewed structured singular value is an NP‐hard problem. In this work, two efficient algorithms that determine upper and lower bounds on the skewed structured singular value are presented. These algorithms are critically assessed using a series of robustness analysis tests on a safety‐critical experimental drive‐by‐wire vehicle. Copyright © 2008 John Wiley & Sons, Ltd.     

Differential effects of methamphetamine and haloperidol on the control of an internal clock.

Humans and animals process temporal information as if they were using an internal stopwatch that can be stopped and reset, and whose speed is adjustable. Previous data suggest that dopaminergic drugs affect the speed of this internal stopwatch. Using a paradigm in which rats have to filter out the gaps that (sometimes) interrupted timing, the authors found that methamphetamine and haloperidol also affect the stop and reset mechanism of the internal clock, possibly by modulating attentional components that are dependent on the content and salience of the timed events. This is the fist report of both clock and attentional effects of dopaminergic drugs on interval timing in the same experimental setting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

用于网络单元时钟的压控石英振荡器

介绍了１５５．５２Ｍｂｉｔ／ｓ、６２２．０８Ｍｂｉｔ／ｓ、２４８８．３２Ｍｂｉｔ／ｓ、１０Ｇｂｉｔ／ｓＳＤＨ系统上的时钟频率源的基本原理，针对ＳＤ我同步对网络单元时钟要求的３８．８８ＭＨｚ压控振荡顺频率源进行了设计，当环境温度在０℃到７０℃范围内变化时，压控振荡器的频率漂移优于±１×１０＾－６，瞬时频率稳定定优于１．２５×１０＾－９。     

Microstructure coarsening during static annealing of 60Sn40Pb solder joints: I stereology

The phase size distributions (PSDs) of the Sn, Pb, and the combined Pb and Sn phases, and the shape factor δ were determined for as-reflowed 60Sn40Pb solder joints and following their annealing at 50°C to 150°C. The PSDs in all cases had a positive skew which was approximated by a log-normal function. The PSDs were time invariant and were in accord with the Bitti and Nunzio model for phase coarsening. The shape factor, δ, decreased with the mean of the combined Pb and Sn phase size, and with temperature. Whether or not δ affects the PSDs is not clear.     

优化光正交码

本文给出了一种构造光正交码的新的组合方法。通过对一类斜Ｓｔａｒｔｅｒ的存在性的讨论，证明了对任意正整数ｖ，当ｖ与６互素时，存在优化（６ｖ，４，１）光正交码。     

Primary Atomic Frequency Standards at NIST

The development of atomic frequency standards at NIST is discussed and three of the key frequency-standard technologies of the current era are described. For each of these technologies, the most recent NIST implementation of the particular type of standard is described in greater detail. The best relative standard uncertainty achieved to date for a NIST frequency standard is 1.5×10⁻¹⁵. The uncertainties of the most recent NIST standards are displayed relative to the uncertainties of atomic frequency standards of several other countries.     

Refined Stick Model for Dynamic Analysis of Skew Highway Bridges

Stick models are widely employed in the dynamic analysis of bridges when only approximate results are desired or when detailed models are difficult or time-consuming to construct. Although the use of stick models for regular bridges has been validated by various researchers, the application of such models to skew highway bridges continues to present challenges. The conventional single-beam stick model used to represent the bridge deck often fails to capture certain predominant vibration modes that are important in obtaining the true dynamic response of the bridge. In this paper, a refined stick model is proposed for the preliminary dynamic analysis of skew bridges. The model utilizes a dual-beam stick representation of the bridge deck. The validity of the model is established by comparing results obtained from the proposed model with numerical solutions obtained for skew plates and a skew bridge. It is shown that this dual-beam stick model is superior to the conventional single-beam model in estimating the natural vibration frequencies and in predicting the predominant vibration modes of the bridge. Because of its simplicity and relative accuracy, this model is recommended for the preliminary dynamic analysis of skew highway bridges.     

DDR2在一种电脑主板上的接口设计

根据DDR2的技术规范，在介绍了DDR2SDRAM的基本特征、工作原理的基础上，分别针对主板上内存部分与北桥、时钟发生器以及电源部分的连接做出了相应的研究，并使用Cadence，Allegro工具软件对接口电路进行了优化设计。