Synthesis of amphiphilic magnetic microspheres by dispersion copolymerization of styrene and poly(ethylene oxide) macromonomer

Amphiphilic magnetic microspheres ranging in diameter from 5 to 100 µm were prepared by dispersion copolymerization of styrene and poly(ethylene oxide) vinylbenzyl (PEO‐VB) macromonomer (MPEO) in the presence of Fe₃O₄ magnetic fluid. The effects of various polymerization parameters on the average particle size were systematically investigated. The average particle size was found to increase with increasing styrene concentration and initiator concentration. It also increased with decreasing stabilizer concentration and molecular weight of MPEO. The content of the hydroxyl groups localized in the microspheres ranged from 0.01 to 0.2 mmol g^?1. © 2003 Society of Chemical Industry     

储层应力敏感性影响因素研究

全面分析储层应力敏感性产生的机理认为，外部因素的改变会引起储层产生应力敏感性．而储层岩石物性等内部因素对应力敏感性的强弱起决定性作用。室内岩心应力敏感性评价时．仪器与设备的精度、加载与卸载方式、实验用流体类型以及各种人为因素等都会对评价结果产生影响，其中岩心密封套在高压、高温条件下的密闭性会对实验结果产生较大影响。所以储层应力敏感性不应该从孔隙度和渗透率的高低进行简单评价，中、高渗储层和低渗储层在生产过程也都可能表现出较强的应力敏感性现象。     

五种恒虚警方法性能分析

比较了五种恒虚警方法在各种杂波背景下的检测性能,得出CMLD-CFAR是工程上可以实现且检测性能比较好的一种恒虚警处理方法.     

Study of Disk-Loaded Waveguide Filled with Plasma

Recently disk-loaded waveguide has been widely used in high-power traveling wave tubes (HPTWT). It has been shown in many experiments that the interaction efficiency and output power can be increased greatly by injecting plasma into the vacuum microwave device. Using field analysis, the dispersion characteristics and the interaction impedance of the disk-loaded waveguide filled with plasma are analyzed in a strong longitudinal magnetic field. In conclusion, the frequency of the TM₀₁ mode increases as the density of the plasma increases. It also can be found when the plasma density increases to a large scale, the TM₀₁ mode of the disk-loaded waveguide overlaps the TG mode, these two modes couple each other and form the new hybrid modes.     

径向水平井弯曲转向机构影响因素仿真研究

针对径向水平井钻进中钻杆弯曲转向前进运动困难的问题,通过建立弯曲转向机构仿真有限元模型,对其主要影响因素:滑道轨迹曲率、间隙、工作压力、滚轮形状与位置和钻杆壁厚等用ANSYS软件进行仿真研究。研究表明:影响截面变形的主要因素是滑道曲率的改变和滑道摩擦因数,钻井失败时钻杆所受阻力的增大不是因为升高工作压力导致截面变形过大与滑道干涉所致,钻杆经校直段,钻头中轴线与校直中心线存在一定的角度,即钻杆的前进轨迹就会偏离理论值,或与地层干涉,或可能再次发生弯曲变形;另一主要原因是转向器滑道工作恶化。增加钻杆壁厚,降低工作压力和滑道摩擦因数,设计合理弯曲转向机构是解决问题的关键。     

忠武输气管道悬索跨越设计创新及探讨

忠武输气管道有4次悬索跨越,分别是蚂蝗溪悬索跨越、木龙河悬索跨越、马水河悬索跨越、野三河悬索跨越。文章介绍了这几座悬索跨越管桥设计中采用的多项新技术,如采用热聚乙烯半平行钢丝索代替以往的钢丝绳;采用钢管塔架代替以往的角钢塔架;根据地形地貌特点变换风索型式或取消塔架等。这些新技术、新设计在工程中均取得了良好的效果。另外,文章还针对悬索跨越桥面结构型式、预拱度设置、不对称荷载的影响、风索基础的设置等问题进行了探讨。     

陶瓷企业实施MRPⅡ现状及问题分析

分析了我国陶瓷企业实施制造资源计划的现状，并提出了成功实施的方略，最后通过实例进行了分析。     

线性调频雷达最小作用距离范围内目标距离的测量

介绍了一种新的探测雷达最小作用距离的方法,打破了传统的最小跟踪距离受发射脉宽局限的限制,重点介绍对发射线性调频信号的雷达的近距离探测方法,并给出了仿真计算结果。     

电磁超声流量计的研制

基于电磁声换能器的原理，研制了一种新型的电磁超声流量计，并讨论提高测量精度的措施。     

Microscale Patterning of Mesoscopic PZN-PT Single Crystal Films by Crystal ion Slicing and Laser-Induced Etching

Advances in the fabrication of solid-solution single crystal relaxor ferroelectrics have made it possible to produce highly efficient piezoelectric crystals, and have attracted renewed interest in the use of these crystals for a new generation of piezoelectric transducers, actuators and sensors. Of particular interest is their incorporation into micro-electromechanical systems (MEMS). In this paper we report on the laser-induced wet chemical etching of lead zinc niobate-lead titanate (PZN-PT) in hydrochloric acid (HCl). Argon-ion laser radiation at power levels up to 4 W is focused to a spot diameter of about 15μm and results in the chemical etching of grooves at patterning speeds up to 5μm/sec. Crystal ion slicing, an ion-implant-based film separation technique, is used in combination with laser etching to form 5 to 10μm-thick patterned and freestanding films for incorporation into micro-electromechanical devices.