Approximation Optimal Vibration Control with Applications to Jacket Offshore Platforms with Nonlinear Dynamic Characteristics

International Journal of Control, Automation and Systems - The vibration control problem of offshore jacket platforms is studied. The model of offshore platforms with nonlinear interactions of the...     

Stochastic control via direct comparison

The standard approach to stochastic control is dynamic programming. In this paper, we introduce an alternative approach based on direct comparison of the performance of any two policies. This is achieved by modeling the state process as a continuous-time and continuous-state Markov process and applying the same ideas as for the discrete-time and discrete-state case. This approach is simple and intuitively clear; it applies to different problems with, finite and infinite horizons, discounted and long-run-average performance, continuous and jump diffusions, in the same way. Discounting is not needed when dealing with long-run average performance. The approach provides a unified framework for stochastic control and other optimization theory and methodologies, including Markov decision processes, perturbation analysis, and reinforcement learning.     

Multiple pharmacological effects of olive oil phenols

Olive oil is a unique component of Mediterranean diet and is likely to be partially responsible for the health effects of this diet. Although the medicinal potential of olive oil has been largely attributed to the antioxidant effects of bio-phenols derived from olive oil, accumulating evidence strongly suggests that, to elucidate olive oil’s benefits to human health, we have to go beyond antioxidants. In this communication, through summarizing the reference-reported and database-recorded pharmacological information of olive oil phenols, we reveal that multiple pharmacological effects, other than antioxidant potential, are involved in olive oil phenols, which is of significance for understanding the health benefits of olive oil in the Mediterranean diet.     

综合地基处理技术在大型油罐建设中的应用

随着国家能源建设的发展,沿海软弱复杂地基上建造大型油罐的情形越来越多。如何安全、经济和高效的治理油罐软弱地基成为迫切的课题。本文结合近十年来几个代表性的工程实例,探讨了多种地基处理工艺相结合的综合治理法的适用性和应用前景。     

不同被检材料中不同缺陷超声波检测的波形识别

超声波检测技术由于具有费用低,灵敏度高,对缺陷定位准确等优点而被广泛使用,但对各种缺陷的波形识别技术至今没有完整的系统性,长期以来一直是人们研究的热点。本文将对不同被检材料中不同缺陷超声检测的波形识别与定性问题进行阐述。     

支持软件过程可信评估的可信证据

近年来,软件可信一直是人们争论的焦点.一种比较共识的观点认为,软件可信是软件行为符合预期的程度.质量形成于过程,显然,建立质量信心的证据也散布于过程.软件开发过程中,主体、行为和各种保障手段则是建立软件可信的基本依据.基于证据的决策和管理是现代质量理论的核心,基于证据、数据驱动的软件工程都是试图从客观数据的角度去解决问题.在国家自然科学基金等计划的支持下,从过程保障的角度提出了软件过程可信度模型,其中,证据作为建立软件可信、支持可信评估的基础要素,是模型非常重要且基础的组成部分.主要研究该模型中的证据体系,遵循完整性、必要性、兼容性和可持续性这4项原则,基于过程管理的基本要素,通过调研以及与CMMI等软件过程参考模型的对接来提炼、定义和质证模型中的可信证据,使证据具备良好的公信力和可比性;同时,增加了部分目前其他模型都没有涉及的证据来刻画对软件过程的可信增强,从而建立了一个从可信实体、可信行为、可信制品这3个目标进行可信保障、并覆盖软件过程全生命周期的证据体系.该证据体系科学、客观并具有良好的公信力,结合可信度模型的其他部分,可以实现基于证据的、自底向上的软件过程可信评估,可供软件组织广泛采用.     

Numerical Analysis and Verification of the Gas Jet from Aircraft Engines Impacting a Jet Blast Deflector

The process of the gas jet from aircraft engines impacting a jet blast deflector is not only a complex fluid–solid coupling problem that is not easy to compute, but also a safety issue that seriously interferes with flight deck environment. The computational fluid dynamics (CFD) method is used to simulate numerically the impact effect of gas jet from aircraft engines on a jet blast deflector by using the Reynolds-averaged Navier-Stokes (RANS) equations and turbulence models. First of all, during the pre-processing of numerical computation, a sub-domains hybrid meshing scheme is adopted to reduce mesh number and improve mesh quality. Then, four different turbulence models including shear-stress transport (SST) k-w, standard k-w, standard k-ε and Reynolds stress model (RSM) are used to compare and verify the correctness of numerical methods for gas jet from a single aircraft engine. The predicted values are in good agreement with the experimental data, and the distribution and regularity of shock wave, velocity, pressure and temperature of a single aircraft engine are got. The results show that SST k-w turbulence model is more suitable for the numerical simulation of compressible viscous gas jet with high prediction accuracy. Finally, the impact effect of gas jet from two aircraft engines on a jet blast deflector is analyzed based on the above numerical method, not only the flow parameters of gas jet and the interaction regularity between gas jet and the jet blast deflector are got, but also the thermal shock properties and dynamic impact characteristics of gas jet impacting the jet blast deflector are got. So the dangerous activity area of crew and equipments on the flight deck can be predicted qualitatively and quantitatively. The proposed research explores out a correct numerical method for the fluid–solid interaction during the impact process of supersonic gas jet, which provides an effective technical support for design, thermal ablation and structural damage analysis of a new jet blast deflector.     

内蒙古边墙里矿区银铜铅锌矿床成矿地质条件及找矿模型

边墙里矿区位于内蒙-大兴安岭褶皱系华力西优地槽褶皱带东部,处于内蒙古浩布高-敖脑大坝铜、铅、锌成矿带上,是寻找构造蚀变岩型银多金属矿以及矽卡岩型铜铅锌多金属矿的有利地区,尤其是NW向和NE向断裂构造发育区,为成矿有利区段。该矿带现已发现双尖子山超大型热液型矿床、浩布高矽卡岩型铜多金属矿等多个大中型矿床。为进一步查清成矿带的成矿地质条件和成矿规律,在1∶5万区域矿产地质调查的基础上,选择边墙里矿区进行矿产勘查工作,相继开展了1∶1万地质草测、1∶1万电法测量、1∶2.5万土壤测量和槽探工程控制。对矿区取得的地质勘查资料进行了综合研究,结果表明：①矿区内圈出了8条矿化带,矿化带主要位于构造蚀变带上,长度为20~550 m,出露宽度为0.6~8.0 m,与矿化有关的主要蚀变有硅化、方铅矿化、闪锌矿化、黄铜矿化等;②矿区共圈定了4条矿体,其中,2条铅矿体,1条银铅矿体,1条银铜铅锌多金属矿体,矿床类型为构造热液型矿床,矿体多呈脉状、透镜状、带状等;③矿化带严格受控于地质构造,多呈NW、NE向带状、脉状展布,次级韧性-韧脆性构造带是控矿和储矿的有利部位;④矿区内圈出了10处土壤化探综合异常和5处激电异常,二者异常套合好,峰值明显,8条矿化蚀变带和4条矿体均分布于物化探异常内。在上述分析的基础上,根据矿床地质特征及物化探异常特征,构建了综合找矿模型,并据此在矿区内圈定了3处找矿靶区（编号为B1,B2和B3）,其中,B2区为矿区最有潜力的找矿靶区,进一步工作有望圈出有开采价值的矿体;根据地表探矿工作成果,预测矿区内远景银铜铅锌（334）资源量达到中型以上。     

藏东母拉同铅锌矿地质特征及控矿因素

母拉同矿床大地构造位置处于班公湖-怒江蛇绿混杂岩带北东侧边界处,属三江成矿带中北段,区内成矿地质条件良好。分别从地层、构造、岩浆岩、1∶5万水系沉积物测量等方面总结了矿区成矿地质背景,分析了水系沉积物异常特征及岩石地球化学剖面特征,总结了矿床控矿因素。研究表明：①母拉同铅锌矿床具有良好的找矿潜力,区内NW向2组次级断裂破碎带的交汇部位为主要的容矿空间;②成矿有利地段具有明显的Ag、As、Cu、Pb、Sb、Sn等元素异常组合,且异常浓集中心较为突出;③成矿物质来源与超基性岩块无明显的成因联系,而与中酸性闪长玢岩脉存在成因关系;④硅化、褐铁矿化为矿区重要的间接找矿标志,地表铅锌矿（化）体露头、褐铁矿带为矿区的直接找矿标志;⑤矿石以侵染状、脉状为主,团块状、角砾状矿石主要分布于破碎带中。上述分析对于进一步在班公湖-怒江蛇绿混杂岩带东段寻找铜、铅、锌等有色金属矿产资源具有一定的参考价值。     

注水管柱蠕动机理分析及蠕动量计算

注水管柱在工作过程中可能会发生蠕动现象,影响了封隔器的使用寿命和注水开发的效果。对坐封
后的封隔器进行受力分析,从力学角度探讨了注水管柱蠕动现象产生的机理,为合理设计注水管柱和防止蠕动现
象的发生提供了理论依据。以管柱力学分析为基础,提出了注水管柱蠕动量计算的方法,并进行了实例计算,研究
成果对准确分析注水管柱力学性能、优化施工工艺参数、提高注水作业有效期有重要意义。