可调螺距螺旋桨船舶的操纵运动数学模型

为利用模拟器对可调螺距螺旋桨(CPP)船舶操纵运动进行仿真,应用船舶操纵性分离建模理论,基于荷兰船模试验水池B系列螺旋桨的敞水试验结果,利用Akima插值获得了不同类型的CPP在不同螺距比时的四象限推力系数和扭矩系数,求得CPP的推力和扭矩,建立了CPP船舶的平面运动数学模型.模型充分考虑了风、流对船舶操纵的影响,并可适用于CPP船舶常速域和低速域的操纵运动仿真.仿真结果与实船试验结果吻合较好,能够满足大型船舶操纵模拟器对船舶运动数学模型仿真精度的要求.     

海洋石油支持船动力定位模块推力分配策略

为了实现海洋石油支持船动力定位模块中的推力分配子功能,提出在现有航海模拟器的基础上升级添加动力定位模拟器模块,研究其中的推力分配方法及实现。利用伪逆法进行推力分配,采用动态链接库技术完成Matlab仿真代码转化,联合QT界面形式完成软件功能模块设计,通过软件实时对控制力向量进行推力分配计算并显示。研究结果表明,该推力分配子功能模块能够有效并快速进行推力分配计算,可以作为子功能集成于现有航海模拟器中。     

导管调距桨全回转拖轮停船运动建模与仿真

针对配备了双导管调距桨的全回转拖轮进行紧急停船运动仿真.基于分离型建模思想,建立全回转拖轮的停船运动数学模型.采用塔格尔特剩余阻力图谱获得不同弗汝德数下的剩余阻力系数,建立适用于常速域和低速域的拖轮阻力模型.通过修正后的JD7704导管+Ka4-70螺旋桨图谱与荷兰船模试验水池最新提出的C4-40调螺旋桨图谱,获得不同水动力螺距角与螺距比下的推力系数,建立适用于导管调距桨实际操纵工况的推力模型.仿真结果显示,所建模型可满足拖轮操纵模拟器中全回转拖轮紧急停船运动精度的要求.     

半潜式自航工程船动力定位模型研究

近年来随着海洋油气开发的广泛需求,我国动力定位技术自主化研究也逐渐展开。为验证半潜式自航工程船的动力定位性能,文中建立了研究半潜式自航工程船的动力学模型的坐标系统。在此基础上,建立了半潜船的运动数学模型以及控制系统需要的运动模型。采用模块法,对影响半潜船的海风、海浪、海流等外界干扰载荷进行了最优计算。通过对环境载荷各个方向的力和力矩的仿真实验,获得了半潜船的水平运动时历曲线和船舶纵向、横向、艏向的运动变化曲线。运动模型的输出结果与半潜船缩比模型的水池试验结果运动趋势一致,满足精度要求。     

侧推器协助船舶靠离泊操纵的数学模型

给出一种港内运用侧推器协助靠离泊操纵的数学模型.模型吸取日本MMG分离建模的思想,以船、桨、舵单独性能为基础,并考虑其各部分之间的相互干涉,同时考虑到靠离泊的船舶运动为低速、大漂角的特点,对作用于船体上流体力及桨、舵力都提出了相应的算法,将侧推器数学模型应用到该模型中,并运用MATLAB语言以某集装箱船为例进行了模拟仿真.经有关船长验证,仿真计算结果基本满足工程要求,可为完善船舶操纵模拟器提供一定的理论基础.     

"育鹏"轮斜航水动力数值计算及运动仿真

为了建立高精度船舶运动数学模型,以目前国内最大、最先进的大连海事大学教学实习船"育鹏"轮为研究对象,采用计算流体力学方法,分别对该船模压载状态下的直航运动和斜航运动水动力进行数值计算,将直航阻力系数计算结果与船模物理水池试验数据进行比较,验证了计算方法的可行性;对斜航水动力系数和力矩系数利用最小二乘法进行多项式拟合求取相关操纵性斜航水动力导数,代入"育鹏"轮六自由度运动数学模型中,用于预报和运动仿真.将部分仿真试验结果与实船海试数据进行对比,吻合较好,误差均在12%以内,验证了数学模型的正确性,提高了航海模拟器数学模型的精度.     

正横规则波中游艇操纵运动仿真

针对游艇与常规排水型船舶在高速运动时所受水动力存在明显差别的问题,提出一种提高游艇模拟器中游艇运动数学模型仿真精度的方法.以某游艇为研究对象,结合国内外研究现状,将船舶操纵性方程与耐波性方程有机结合,建立正横规则波中游艇4自由度运动数学模型.采用查洁法对船体水动力进行计算,并通过编程实现.最后,将仿真结果与船模试验数据进行对比验证.结果表明,该模型误差较小,满足游艇模拟器对游艇运动仿真精度的指标要求,具有工程实用价值.     

吊舱推进船舶操纵性仿真研究

为进一步提高吊舱推进船舶的操纵性能,根据船舶在操纵过程中的运动状态,建立了吊舱推进船舶综合仿真模型。分析吊舱推进器推力大小、回转角度与船舶操纵的关系,改进了现有三自由度非线性船舶运动方程,提出了吊舱推力矢量模型以及具体计算方法。在Matlab平台下分别实现了吊舱推进船舶和传统推进船舶模型的仿真,并比较了这两种船的回转操纵和Z形操纵性能。结果表明该模型能正确地反映吊舱推进船舶操纵运动状态并为吊舱推进控制技术的研究提供了可信的数学模型。     

航海模拟器研发设计之探讨

航海模拟器从开始利用以来,从当初的小型单功能模拟器发展到今天的大型操纵模拟器,对模拟器的使用也从纯粹的教学发展到今天的在通航评估、工程论证等工程项目中发挥了重要的作用.回顾国内模拟器发展的同时介绍了挪威KONGSBERG公司Polaris大型船舶操纵模拟器系统,研究其在设计上的优点,参考STCW马尼拉修正案对船舶操纵模拟器提出的新要求.探讨模拟器今后的研制方向,并就船舶操纵模拟器的研制提出粗浅意见.     

船舶空调舱室夏季制冷工况的建模与仿真

为解决船员培训中船用空调模拟器操作问题,建立了船用空调仿真模型,利用Simlink模块得出的仿真曲线为船用空调模拟器设计提供了可靠的依据,实现了对船用空调系统运行工况的实时仿真、动态仿真.正确可靠的数学模型和精确的仿真曲线为船舶空调模拟器的设计提供了有力的保证,为船用空调的设计提供了可靠的科学依据.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.