基于多材质复合管柱的裸眼井壁支撑工艺及应用

已完钻超深裸眼水平井侧钻技术是经济、高效开发油藏剩余油的主要手段之一，传统的磨铣钢套管开窗侧钻技术存在下入摩阻大、磨铣耗时长导致开窗失败等问题。为此，提出了基于多材质复合管柱的超深水平井裸眼井壁支撑工艺，结合中国西北油田已完钻超深裸眼水平井井况，首先，提出了基于“铝合金+碳钢”的多材质复合管柱组合及设计方法；其次，开展了基于管柱实物屈曲实验数据的管柱临界屈曲载荷计算模型适用性评价，并优选出了适合于“铝合金+碳钢”多材质复合管柱的屈曲临界载荷计算模型；最后，研究了综合考虑管柱扭矩、摩阻、刚性、井眼条件、管柱强度及材质的多材质复合管柱下入性分析方法，并利用下入性分析软件对西北油田顺北X1井、X2井、X3井、X4井复合管柱进行了下入可行性评价。该方法在X1井和X2井得到成功应用，进一步论证了该工艺现场应用的可行性。研究成果可为超深水平井裸眼井壁支撑的复合管柱设计和下入可行性评价提供理论参考。     

建党百年广东省科技创新事业迈向新征程

与中国共产党的百年发展历程相伴的是国家科学技术的快速发展.广东省作为国家社会与经济发展的前沿阵地,其科学创新的发展经验能够代表国家在改革浪潮中的发展变化.尤其是改革开放伟大征程的开启以及粤港澳大湾区规划的提出,促进了广东省科技创新事业的快速发展.广东省目前已成为国际科技创新的重要发生地,甚至在一些科技创新领域领先全球.文章通过回顾改革开放40多年来广东省科技创新取得的伟大成就,从政策、人才培养与引进、制度创新与科创平台建设、企业发展等领域分析广东省科技创新发展的特征、优势以及独特的做法,以期为我国科技创新的发展提供借鉴.     

Meet-Cloud for Secure and Accurate Distribution of Negative Messages in Vehicular Ad hoc Network

Keeping Vehicular Ad hoc Network(VANET) from attacks requires secure and efficient distribution of information about bad entities. Negative messages are pieces of information that define the negative attributes of vehicles. By formally defining the negative message, we observe that accuracy is essential for its efficient distribution. We formally define the coverage percentage and accurate coverage percentage to describe the availability and distribution efficiency of negative message. These two metrics can jointly evaluate the performance of a distribution method. To obtain both high coverage percentage and high accurate coverage percentage, we propose meet-cloud, a scheme based on meet-table and cloud computing to securely and accurately distribute negative messages in VANET. A meet-table in a Road Side Unit(RSU) records the vehicles it encounters. All meettables are sent to cloud service to aggregate a global meet-table. The algorithm for distributing and redistributing negative messages are designed. Security analysis shows that meet-cloud is secure against fake and holding on to negative message attacks. Simulations and analysis demonstrate that meet-cloud is secure under denial of service and fake meet-table attacks. The simulation results also justify that meet-cloud outperforms the RSU broadcast and epidemic model.     

云计算视角下可验证计算的分析研究

云计算能否在未来的各个领域中被广泛运用,决定因素在于其可信度。可验证计算在检测云计算结果的可信度方面具有其独特优势。利用可验证计算协议可验证云服务器端所返回的数据是否正确,它成为实现云计算可信度的重要保障。文中在阐述可验证计算基本内容和相关设计原则的基础上,分析了可验证计算协议的一般流程、设计原则及计算模型,并结合基于交互系统的可验证计算协议分析,探讨在云计算视角下可验证计算的研究展望。     

基于回波预处理和相参积累的C&I干扰抑制算法

C&I(chopping and interleaving)干扰是一种针对线性调频(linear frequency modulation, LFM)雷达的典型干扰样式, 干扰子信号调频斜率与雷达发射信号相同, 利用信号处理工具分离真实回波与干扰信号难度较大。针对该问题, 以LFM相参雷达抗自卫式C&I干扰为背景, 提出基于回波预处理和相参积累的干扰抑制算法。根据估计的回波时延, 设置距离窗截取受干扰回波段, 在此基础上, 通过对回波预处理, 改变不同重复周期内假目标的快时间位置分布, 通过相参积累实现干扰抑制。仿真试验表明, 所提算法能够有效抑制强干扰背景下的C&I干扰, 干扰抑制后真实目标检测概率大幅提高, 虚假目标数量明显减少。     

Geochemistry of Clayey Aquitard Pore Water as Archive of Paleo-Environment,Western Bohai Bay

The record of paleo-environment in clayey aquitard pore water is much more effective relative to aquifer groundwater owing to the low permeability of clayey aquitard. Oxygen-18 (18O), deuterium (D), an...     

利用SRTM数据修测高山区地貌的探讨

在高海拔区域测制地形图,如青藏高原地区,所获取的遥感影像局部存在着大范围的高山阴影或云雪覆盖,造成立体观测地貌困难的现象,探讨应用SRTM数据对这类特殊区域地貌进行修测补绘。介绍了数据处理的作业过程,并对实验区SRTM与SPOT5影像立体测图成果进行实验对比分析,成果符合要求。     

磁流变液中磁性颗粒成链与团聚的临界特征分析

热运动对纳米级磁流变液系统的颗粒团聚行为和宏观流变特性扰动影响不可忽视.为研究施加外磁场后系统微结构与热运动间的关系，探讨在不同颗粒粒径情况下热运动能量在系统总能量中的占比.采用CCD设计方法，分析Monte Carlo仿真获取的颗粒位形信息，生成关于外磁场磁感应强度、颗粒粒径和体积分数的系统热耦合系数<λ>回归模型;成链团聚的临界颗粒粒径计算值比文献经验值高出约23%，证实在考虑系统内多因素的综合影响下，纳米级磁流变液具有更严格的流变现象临界发生条件.     

Fuzzy Views on Black-Litterman Portfolio Selection Model

In this paper, views of investor are described in fuzzy sets, and two fuzzy Black-Litterman models are constructed with fuzzy views and fuzzy random views respectively. In the models, expected returns and uncertainty matrix of views are redefined and the views are formulated by fuzzy approaches suitably. Then the models are tested with data from Chinese financial markets. Empirical results show that the fuzzy random views model performs the best, and both the fuzzy models are better than the traditional ones, demonstrating that the fuzzy approaches can contain more information in the views and measure the uncertainty more correctly.     

Speeding Up the GVW Algorithm via a Substituting Method

Journal of Systems Science and Complexity - The GVW algorithm is an efficient signature-based algorithm for computing Gröbner bases. In this paper, the authors consider the implementation of...