SF_6旋弧式断路器似稳吹弧磁场的数值分析

SF_6旋弧式断路器依靠相位上滞后的吹弧磁场对电流产生的电动力,使电弧在SF_6气体中快速旋转而熄灭。这种断路器的灭弧机理与磁场形态有密切关系,吹弧磁场是由通过吹弧线圈的电弧电流与铜套中的涡流共同产生的。本文用数值方法研究这种吹弧装置的似稳态磁场,计算结果与实验数据十分吻合,说明所采用的方法具有满意的精度。通过在不同条件下对吹弧磁场的数值分析,找到了吹弧装置的结构参数和材料性能与磁场的关系,并且还提出了在电弧电流零区获得最大磁场的途径。     

辽河油田L46块开发前期油藏工程研究

首先分析了辽河油田Ｌ４６块的地质特征，然后分析和介绍了开发前的油藏工程，主要包括前期准备井的部署原则，实施要求，指出该块必须采用注水补充能量的开发方式进行开发，给出了合理的井冈井距、即合理井距为３００ｍ，采用正方形并网，确定了油井产能为平均单井产油１０ｔ／ｄ，最后予测了年产原油６．６×１０４ｔ／ｄ，采油速度为２．２０％．     

走近"习性"、"资本"和"场"--读《布尔迪厄访谈录》

布尔迪厄以访谈的形式,阐述了在他的理论体系中起核心组织作用的三个概念"习性"、"资本"和"场".习性是一个构筑在实践层面上的后天获得的性情系统,是在实践中形成的即兴创作的能力.资本是以同一的形式和扩大的形式获取利润的潜在能力,它实质上是权力的一种形式.场涉及的是对人们的关系、地位的分析,对行动者占据的位置的多维空间的阐述;每个场都是斗争的场所.     

新型两性离子聚合物FA369钻井液在樊学油田的应用

介绍了樊学油田地质概况,论述了新型两性离子聚合物FA369钻井液的配方及优点,提出了现场维护要点。     

甘谷驿油田长6油层储层成岩作用及其对储层物性的影响

甘谷驿油田长6油层为湖泊三角洲平原分流河道砂体及三角洲前缘水下分流河道、河口坝砂体．砂岩以中细粒长石砂岩为主，主要成岩矿物有绿泥石环边、方解石胶结物、长石和石英加大生长、伊利石、伊一蒙混层、钠长石和高岭石等．在成岩过程中，强烈的压实作用及胶结作用导致原生孔隙丧失殆尽，是储层成为特低渗透率的主要原因；而晚期的溶蚀作用，特别是方解石、浊沸石的溶解，使得储层的孔隙度和渗透率有所改善，这才使得鄂尔多斯盆地长6层发育部分“甜点”储层，成为有利的储集相带．     

The natural history of the parasitic wasp Trogus pennator (Hymenoptera: Ichneumonidae): Host‐finding behaviour and a possible host countermeasure

The parasitic wasp Trogus pennator (Ichneumonidae) attacks the larvae of swallowtail butterflies (Papilionidae). Female T. pennator were followed in the field as they searched for larvae of the zebra swallowtail butterfly, Eurytides marcellus (Papilionidae), feeding on Asimina (Annonaceae) in central Florida, USA. Predictions of host‐finding theory and interactions with the host were thus investigated in a natural setting. Wasps seldom flew to plants other than Asimina and apparently recognized the plants by visual cues. Plants were attractive regardless of host presence, as the wasps approached plants lacking E. marcellus feeding damage twice as often as they approached damaged plants. However, wasps approached damaged plants at a rate greater than their frequency in the Asimina population, indicating that they can detect host damage before they approach the plants. After approaching within 0.5?m of plants, wasps tended not to land on plants lacking feeding damage. A comparison of the plants they landed on, however, showed no consistent preferences for damaged plants. The weaker trends in the latter data indicate that the presence of feeding damage was not the sole criterion for landing, although it evidently influenced behaviour. After landing, wasps spent more time searching damaged plants than undamaged plants. Butterflies preferred to oviposit on plants shorter than those searched by T. pennator. Possible adaptive consequences of this phenomenon are discussed.     

FPGA在图象处理中的应用

介绍了FPGA的硬件结构和特性 ,以及采用现场可编程器件FPGA设计图象处理板的原理和设计方法 ,给出了实现图象左右翻转的应用实例。实践证明这种方法速度快 ,编程简单 ,设备具有很高的性能价格比。     

建立麦克斯韦方程组的新途径

用普通物理学的方法推导了不同惯性系之间产场量的变换式，在此基础上，给出了一咱简便、快捷并且物理意义清晰的建立麦克斯韦方程组的新途径。     

新产品WK-668在下二门联合站的性能评估及应用

分析了河南下二门油矿含油污水处理现状，论述了新型破乳剂WK-668的应用。     

Speed-Sensorless Control Using Elman Neural Network

1. INTanDUCTIONControlling induction motor without sensor is available nowadays. In order to aclileve two-level closed lOops,i. e., digital current lOop and digital speed loop, it is necessary to sense.and digitize the motor phase currentand motor speed. Howver, the sensors involved have the followillg disadvantages. First, they aJre eXPensiveand make up a significan portion of the total cost. Second, they may result in electrical or mechaulcal fault.Based on speed estimation, it is pos…