双基地ISAR成像分析

在建立远场条件下双基地ISAR转台模型的基础上,阐述了双基地ISAR的成像原理。针对双基地ISAR系统中相对转角计算复杂的问题,给出了一种利用合多普勒带宽计算双基地ISAR方位分辨率的方法。详细分析了双基地ISAR系统的收、发分置结构对目标成像的影响,针对双基地ISAR系统中机动目标多普勒频率信息的时变特性,将基于时频分析技术的距离-瞬时多普勒成像算法引入双基地ISAR目标像的重建过程中。最后,仿真实验验证了算法的有效性。     

Global space–time multiquadric method for inverse heat conduction problem

In this paper, a radial basis collocation method (RBCM) based on the global space–time multiquadric (MQ) is proposed to solve the inverse heat conduction problem (IHCP). The global MQ is simply constructed by incorporating time dimension into the MQ function as a new variable in radial coordinate. The method approximates the IHCP as an over‐determined linear system with the use of two sets of collocation points: one is satisfied with the governing equation and another is for the given conditions. The least‐square technique is introduced to find the solution of the over‐determined linear system. The present work investigates two types of the ill‐posed heat conduction problems: the IHCP to recover the surface temperature and heat flux history on a source point from the measurement data at interior locations, and the backward heat conduction problem (BHCP) to retrieve the initial temperature distribution from the known temperature distribution at a given time. Numerical results of four benchmark examples show that the proposed method can provide accurate and stable numerical solutions for one‐dimensional and two‐dimensional IHCP problems. The sensitivity of the method with respect to the measured data, location of measurement, time step, shape parameter and scaling factor is also investigated. Copyright © 2010 John Wiley & Sons, Ltd.     

冷却塔设计布置实例谈

冷却塔的噪声和水雾对周围的环境影响很大,尤其是大型建筑的冷却塔群,由于放置空间所限,在设计中对其进行合理的布置更显重要。通过工程实例,介绍了冷却塔有效排布的思路和方法。     

密闭自控式注水工艺管柱的研制与现场试验

针对聚合物后续水驱井下注水工艺存在的问题,研制了密闭自控式注水工艺管柱.对管柱的结构组成和工作原理进行了分析,并在胜利石油管理局孤岛采油厂注水示范区有针对性的进行了现场试脸和推广应用,结果表明,采用新工艺后的地层吸水量得到明显提高,改善了吸水剖面,提高了测试成功率.新型注水工艺管柱能够有效防止关井后地层返吐造成的出砂现...     

Synthesis and behavior evaluation of a relative permeability modifier

Using N, N-dimethylaminoethyl methacrylate (DMAEMA) and methoxy polyethylene glycol methacrylate (MPEGMA) as raw materials, hydrophobically associating copolymer was synthesized by inverse emulsion polymerization and structurally confirmed by FTIR. Choosing partially hydrolyzed polymer of the copolymer as a relative permeability modifier, its intrinsic viscosity reaches 212.66 mL/g at 25 °C. Its adsorbability on the oil sandstone is investigated, that is to say, the equilibrium concentration is approximately 5100 mg/L while the saturated adsorption is about 0.652 mg/g. Temperature and salt also have a certain effect of RPM system based on the partially hydrolyzed polymer. Finally, the residual resistance factors to water and oil were measured by core displacement test. The results show that the flow resistance of the system to water is 19.9 times as large as that to oil. That is, the system has obvious selectivity to water and oil.     

建场测深技术新进展——三塘湖盆地马朗凹陷石炭系结构属性研究实例

石炭系是三塘湖盆地的重要含油气层系,但由于地震勘探在深层难以得到有效反射信息,导致对盆地内石炭系的内部结构认识不清,制约了油气勘探进程。本文将多频段高信噪比建场测深采集和广义逆二维约束反演为核心的一体化技术,用于该盆地马朗凹陷的油气勘探。应用结果表明,建场测深法能够揭示石炭系多套层系及其中分布的火山岩体,并指出上石炭统哈尔加乌组低阻电性层是泥质碎屑岩发育的烃源层,卡拉岗组和巴塔玛依内山组高阻电性层是火山岩发育的有利储集层,并为钻探结果证实。     

反相悬浮聚合制备淀粉-丙烯酰胺-丙烯酸共聚物暂堵剂

以淀粉、丙烯酰胺、丙烯酸为共聚单体,硝酸铝为交联剂,过硫酸钾为引发剂,Span-60/Tween-60为复合乳化剂,采用反相悬浮聚合法合成了一种新型暂堵剂淀粉-丙烯酰胺-丙烯酸共聚物,并采用SEM和FTIR技术对共聚物进行了表面形貌分析和结构表征;考察了硝酸铝用量、丙烯酸中和度和淀粉用量对暂堵剂吸水性能的影响。实验结果表明,暂堵剂的最佳合成条件:丙烯酰胺5.00 g、环己烷60 mL、0.80 g Span-60、0.40 g Tween-60、丙烯酸中和度80%、淀粉1.50 g、硝酸铝0.02 g、70℃、3 h;在该条件下合成的暂堵剂的吸水倍率最大,且具有适中的强度。     

基于传热正反模型的动态测温方法研究

为减少热惯性温度传感器的动态测温误差,提出了基于传热模型和反演算法的动态测温方法,其实质是将求解被测对象的真实温度转化为一个优化问题.该方法首先建立温度传感器非线性非定常瞬态传热正模型和有限元求解方程,并进行实验验证.在此基础上,推导了瞬态传热一阶敏度计算公式,建立了温度传感器的非稳态反演传热模型,结合快速反演算法,反求作为边界条件的被测对象真实温度.将所提出的动态测温方法应用于具有内外两层套管、传热过程复杂的复合温度传感器.实验和仿真结果均表明,正向模型的仿真值与测量值相比最大误差小于5℃,反演求解的被测对象真实温度误差不超过1％,热响应时间由548 s缩短到106s.应用实例分析结果表明,所提出的动态测温方法具有较高的准确性和快速性.     

四自由度并联工作台的运动学建模

提出一种四自由度并联工作台,进行了机构学分析及其自由度的计算;研究了该机构的运动学建模方法,给出了位置分析的正解、逆解,并阐述丫其应用前景.     

6-HUS并联机构位置逆解与运动学优化设计

针对并联机构设计过程复杂、设计周期长等问题,对6-HUS并联机构运动学逆解及相关参数的优化进行了研究.建立了运动学逆解方程并得到解析解,应用ADAMS软件进行参数化建模并仿真;通过解析解和模拟解的对比,验证模型的正确性;根据性能要求,以滑块最大速度最低为目标对机构结构尺寸进行了优化设计.分析结果表明:该方法方便快捷,缩短了设计周期,降低了产品成本,为同类机构的设计提供了较为精确的实用方法.