Wind turbine response to parameter variation of analytic inflow vortices

As larger wind turbines are placed on taller towers, rotors frequently operate in atmospheric conditions that support organized, coherent turbulent structures. It is hypothesized that these structures have a detrimental impact on the blade fatigue life experienced by the wind turbine. These structures are extremely difficult to identify with sophisticated anemometry such as ultrasonic anemometers. This study was performed to identify the vortex characteristics that contribute to high‐amplitude cyclic blade loads, assuming that these vortices exist under certain atmospheric conditions. This study does not attempt to demonstrate the existence of these coherent turbulent structures. In order to ascertain the idealized worst‐case scenario for vortical inflow structures impinging on a wind turbine rotor, we created a simple, analytic vortex model. The Rankine vortex model assumes that the vortex core undergoes solid body rotation to avoid a singularity at the vortex centre and is surrounded by a two‐dimensional potential flow field. Using the wind turbine as a sensor and the FAST wind turbine dynamics code with limited degrees of freedom, we determined the aerodynamic loads imparted to the wind turbine by the vortex structure. We varied the size, strength, rotational direction, plane of rotation, and location of the vortex over a wide range of operating parameters. We identified the vortex conformation with the most significant effect on the blade root bending moment cyclic amplitude. Vortices with radii on the scale of the rotor diameter or smaller caused blade root bending moment cyclic amplitudes that contribute to high damage density. The rotational orientation, clockwise or counter‐clockwise, produces little difference in the bending moment response. Vortices in the XZ plane produce bending moment amplitudes significantly greater than vortices in the YZ plane. Published in 2005 by John Wiley & Sons, Ltd.     

一种T形高压输电线路故障测距新方法

对T形线路的故障测距，现有方法都是先判断故障支路，再将3端线路等效成2端线路进行测距。但在 T节点附近短路，尤其是经高阻短路时，现有的测距方法由于无法正确判别故障支路而存在一定范围的测距死区。针对上述缺陷，分别假设故障发生在某一支路，由假定正常的2段支路端的电压、电流推算求得 T节点电压和注入假定故障支路的电流，从而分别求得3个故障距离。经证明，求得的3个故障距离有且仅有1个在0和对应支路总长度之间，该距离就是真实的故障距离，故障发生在对应支路上。该方法无需事先判别故障支路即可测距，在 T节点附近经高阻故障时无测距死区。其测距精度理论上不受过渡电阻和故障类型影响，无需故障前数据，且对滤波无高要求。EMTP仿真结果表明该方法正确、有效，测距精度高。     

On the Locus of Speed-Accuracy Trade-Off in Reaction Time: Inferences From the Lateralized Readiness Potential.

Lateralized readiness potentials (LRPs) were used to determine the stage(s) of reaction time (RT) responsible for speed-accuracy trade-offs (SATs). Speeded decisions based on several types of information were examined in 3 experiments, involving, respectively, a line discrimination task, lexical decisions, and an Erikson flanker task. Three levels of SAT were obtained in each experiment by adjusting response deadlines with an adaptive tracking algorithm. Speed stress affected the duration of RT stages both before and after the start of the LRP in all experiments. The latter effect cannot be explained by guessing strategies, by variations in response force, or as an indirect consequence of the pre-LRP effect. Contrary to most models, it suggests that SAT can occur at a late postdecisional stage. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

一种新的数据通讯方式--电力线数据通讯

本文概括叙述了利用电源线路实现数据通信的国际技术背景，我国电力线状况以及能有效解决电力线数据传输中各种干扰问题的扩频通信技术。     

催化裂化大油气管线阻焦剂的研究与开发

介绍了阻焦剂的阻聚分散机理，测定了不同组分的阻焦剂对不同性质原料的阻焦效果，并考察了不同加入浓度对阻焦率以及催化裂化产品分布的影响。试验结果表明：加入50—100μg/g的阻焦剂，可使催化裂化大油气管线阻焦率达到53．7％—63．8％，同时对产品分布及产品性质无不良影响，具有技术经济可行性。     

Modelling of Al2O3 Powder Compaction with Hot Pressing in a Rigid Die

Computer modelling of hot pressing is provided. Kinetics are described for compaction during hot pressing in a rigid die, and the change in density distribution, irreversible solid phase strain accumulation, and equivalent stresses are studied by means of the finite element method. Shrinkage during the preparation of complex-shaped articles by hot pressing pure Al₂O₃ powder in a graphite die without a protective atmosphere and the physicomechanical properties of the finished article are studied. Calculated and experimental results agree satisfactorily.     

矿用交换机用户线接口电路

介绍了一种由新型集成芯片组成的电话用户线接口电路，由用户线功能块DTLM630和可编程单片全双工增量调制解调器CMX639等组成。由于芯片的高度集成化，从而使电路结构简单，使用可靠，是一种新型实用的用户线接口电路。     

SPC在变速器制造中的应用

这里首先建立了SPC系统的数学模型及数据处理模型，在此基础上完成了系统的功能结构设计以及事务处理过程设计，建立了关键工序与质量特性值的选取准则，继而完成了代码设计、数据库设计和故障诊断专家系统的设计：所形成的SPC软件系统达到了原设计指标要求。     

Magnetic properties of high-temperature superconductors: Analysis within the framework of the impurity mechanism

The impurity mechanism proposed earlier is used to interpret the magnetic properties of hightemperature superconductors. The appearance of superconductive granules and the existence of weak bonds in grains of ceramics and in single crystals is explained. The irreversibility line is obtained and its new interpretation as the line of thresholds of appearance of infinite nonsuperconductive cluster is given. The relaxation time of the magnetic susceptibility in alternating magnetic fields is calculated. The decrease of the Meissner fraction with increase in magnetic field and decrease in doping, and other magnetic properties are explained.     

利用Love波特性计算地基动力响应

本文利用Love波弥散特性在频域上对地基出平面振动及扭振问题进行了研究。在计算区域内结构将采用有限单元划分,而在边界上则根据Love 面波特性使用传递边界有限单元。本文同时讨论了不同模态波对结构动力响应的贡献。本文方法也适合于静力分析。