基于压电陶瓷动态信息的结构裂纹识别方法

利用压电陶瓷的动态特性和压电系统的动态信息,对铝梁的裂纹损伤进行了分析研究。随着梁裂纹尺寸的增加,压电陶瓷片的导钠幅值下降,且系统固有频率减小。利用导钠幅值的变化和系统的动态信息,可以对裂纹的位置和尺寸大小进行识别。实验证明该方法的有效性。     

差分跳频通信系统的特点及性能

文章介绍了一种新型的短波跳频通信技术——差分跳频,分析了差分跳频技术区别于常规跳频技术的主要特点。针对按序列检测的信号接收方法,对差分跳频通信系统在AWGN信道下的性能进行了理论分析,同时做出相应的计算机仿真,证实了差分跳频通信技术和按序列检测方法的结合,使通信系统在AWGN信道下的性能得到了比较显著的提升。     

Cover Picture: Arresting,Fixing, and Separating Dimers Composed of Uniform Silica Colloidal Spheres (Adv. Funct. Mater. 12/2006)

In colloidal suspensions of silica, particles undergo constant collisions. By controlling various parameters, the repulsive barrier can be reduced, thereby substantially increasing the number of collision‐induced dimerization events. Xia and co‐workers report on p. 1627 that the dimers could be arrested and then permanently fixed by introducing a small amount of fresh tetraethylorthosilicate into the colloidal suspension, with monodisperse dimer yields of up to 50 %. This yield could be increased to 80 % by centrifugation in a density gradient medium. When fresh tetraethylorthosilicate is introduced into a colloidal suspension of silica spheres, it hydrolyzes and condenses in situ to arrest and fix the dimers resulting from constant collisions between the spheres. By optimizing the experimental parameters (including the length of aging time) and the diameter of the silica spheres, as well as the concentrations of counterions, water, and ammonia, it is possible to routinely produce monodisperse dimers with a yield as high as 50 %. When combined with centrifugation using a density gradient medium, the yield of such dimers could be further increased to 80 %. It is believed that this method will provide a simple and versatile approach to the high‐volume production of dimers from spherical colloids composed of different materials. These dimers may find widespread use in a range of applications such as fabrication of photonic crystals and fundamental studies related to colloidal science.     

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     

Mathematical modelling and numerical simulation of ordered porosity metal materials formation

Ordered porosity metal materials belong to a relatively new class of porous materials named gasars. This paper presents a mathematical model of the complex physical phenomena in the production of gasars. Analyses for heat transfer, solidification kinetics and gas diffusion were coupled to describe the formation of unique gasar structure. Several criterial functions were introduced to provide significant quantitative information about the relationship between the operating technological parameters and the final structure. The computational outcomes of the numerical simulation were compared with the characteristics of real gasar ingots. The model was applied to determine the boundary conditions that would provide approximately constant physical conditions on the solidification front. The structure sensitiveness of gasars with respect to the different technological parameters is discussed.     

产出水处理设备的腐蚀和机械磨损

提供了能够延长与产出水举升、加工、处置和注入有关的油气生产设备使用寿命的成功经验和技术,并按照产出水的处理程序进行介绍,即从油藏中的液体进入井筒到举升到地面(井筒管理),地面生产/加工设备和处理/注入设备的整个处理过程.由于井筒是最主要的设备,多数作业成本都与将液体举升到地面有直接关系,因此要重点强调井筒的管理.通过减少井的事故(抽油杆、油管和泵)可以大大降低操作成本,延长边缘井的生产时间.地面处理成本包括如何使泄漏、漏出物清洗及原油携带量降到最低的费用.上述经验来源于2002年8月对Permian盆地上成功优化水处理成本的作业商进行的采访;已发表的油气技术文献;本文作者在油气作业领域的个人经验(31年以上).     

川合137井大修井工艺技术浅析

在川合137井的修井作业中，运用了多种修井工具和工艺技术。通过内捞、外捞、强提、倒扣、磨铣、套铣、开钻新井眼和铣锥通井的方法，充分解放了油气层，达到了修井目的。其独特的想法、施工和自制工具的成功应用对今后大修井作业具有很高的参考价值。     

番禺30-1砂岩强水驱气藏储层非均质性研究

针对垂向非均质性严重且边底水能量强的番禺30-1气田面临的潜在开发问题，通过岩心分析及测井二次解释，对其夹层特征及储层非均质性等进行了研究，划分出19个流动单元并定量描述了各流动单元的特征参数，建立了该气田的精细地质模型。综合评价表明，新建的地质模型具有较高的精度，为该气藏合理开发提供了坚实的地质基础。     

深水海底泥浆举升钻井技术及其应用前景

为了解决深水钻井中遇到的问题，由Conoco公司领导的工业联合项目组研发了海底泥浆举升钻井（以下简称SMD）技术。采用该技术进行深水钻井时，隔水管内充满海水，泥浆用小直径管线从海底返回，在返回环空中形成两个压力梯度，实现双梯度控压钻井。文中着重介绍了SMD的理论依据、系统工作原理、系统关键设备以及SMD井控程序的HAZOP分析等。从技术适用性、经济性、装备以及可能存在的风险等方面对该技术在南中国海钻井中使用的可行性进行研究，并展望其应用前景。     

关于天然气水合物钻采工艺技术进展的研究

目前全球正面临着前所未有的能源危机，天然气水合物由于储量大、能量密度高而将成为一种诱人的新型能源。天然气水合物主要存在于冻土带和海洋，在地下处于低温和高压状态，以现有的技术，钻井和开采都存在很大的困难。简要介绍了天然气水合物的性质及储量，阐述了天然气水合物钻井的六个挑战及目前国外天然气水合物的两种钻探方法；同时阐述了以热力法、降压法和化学试剂注入法为主的天然气水合物开采方法，并针对天然气水合物钻采技术现状指出了下一步的研究方向。