新矿物与新矿物研究创新探索     

李国武 《地学前缘》2020,27(5):1-9

作为矿物学的重要基础研究方向之一,新矿物的发现及其晶体结构、晶体化学的研究始终备受各发达国家的一贯重视。新矿物的研究和发现及其成果具有国际性,在一定程度上反映了国家在该领域以及整体科技水平和对科学发现的贡献。笔者近年来参与了对若干存疑矿物进行的精细晶体结构与晶体化学研究和矿物学研究,从2005年至今参与发现的23种新矿物均获得国际矿物学协会新矿物及分类命名委员会(IMA-CNMNC)所批准。这些新矿物的获批得益于成功地获取了成分数据、衍射数据和晶体结构的阐明。本文就新矿物的认定规则、申报内容和数据、分类命名、研究内容及工作方法等进行综述,在此抛砖引玉,希望通过交流促进我国新矿物研究领域的发展。  相似文献   

透射边界高频耦合失稳机理及稳定实现——SH波动          下载免费PDF全文

章旭斌  廖振鹏  谢志南 《地球物理学报》2015,58(10):3639-3648

就大型近场波动的高效数值模拟而言,稳定实现高阶人工边界是一个尚未圆满解决的问题.本文针对使用多次透射公式的SH波动集中质量有限元模拟,依据GKS定理的群速度解释,进一步阐明了人工边界与内域离散格式耦合所导致高频失稳的机理,即两者支持群速度指向内域的外行高频平面谐波,波动能量自发地从人工边界进入內域,从而导致失稳,而这类谐波是由集中质量有限元离散引入的.本文提出了消除此种耦合失稳的一种方法:通过修改有限元刚度阵来改变内域离散格式,并保证修改格式的精度不低于原有格式的精度.理论分析和数值实验表明此法能稳定实现透射边界.本文研究结果具有推广应用前景.  相似文献   

The shape of the seismic response interaction diagram: The effect of combination rules in response spectrum analysis     

Manuel Ritto-Corrêa  Ana Rita Tomaz  Luís Guerreiro 《地震工程与结构动力学》2020,49(14):1428-1451

This paper deals with the construction of seismic response interaction diagrams that show the correlation of multiple responses and are important to determine the critical combination of modal responses. Many design problems, such as column design under combined axial force and bending moments, fall into this category. We address general modal and multicomponent combination rules and study their effect on the shape of the response interaction diagrams, thus extending previous work done for quadratic combination rules. Special attention is given to multilinear combination rules which lead to polyhedral shapes. Having developed efficient methods to deal with polyhedral shapes, we explore the idea of adopting a multilinear modal combination rule to compose with a multicomponent percentage rule.  相似文献   

关联规则挖掘在LBS动态数据管理的应用研究     

吴中忠  程新文  陈秀万  张飞舟  吴才聪  陈军峰 《测绘科学》2004,29(5):62-65

为了满足人们能在任意地点、任意时刻存取任意数据的需求,基于位置的服务(LBS,LocationBasedService)需要进行动态数据管理。一种解决方案是服务器根据关联规则挖掘出的规律,对热点数据进行预测,并利用数据广播技术将热点数据不断地推向移动客户机。但经典的Apriori算法并不适合时序数据的处理,而现有的时序关联规则挖掘算法又对服务的关联时间阀值考虑不够,故本文对经典的Apriori算法进行改进,使之适应动态数据管理的需要,从而为解决LBS动态数据管理问题提出新的解决思路。  相似文献   

大城市边缘区人居环境系统演变规律——以广州市为例   总被引：4，自引：3，他引：1  

祁新华  程煜  陈烈  朱宇 《地理研究》2008,27(2):421-430

文章以广州市为例,揭示了大城市边缘区人居环境系统的演变规律:首先,人居环境系统演变过程可以划分为初期、中期、后期三个阶段,各阶段在城市化水平、经济发展状况、基础设施建设、社区形态、景观类型、土地利用等方面都呈现出显著的特征;其次,提出了人居环境容量概念,并借助于GIS空间分析方法,发现边缘区人口密度不断地增加,人居环境容量逐步趋于饱和;第三,大城市边缘区人居环境演变呈现出不均衡的周期性变化。在此基础上,借鉴Verhulst逻辑斯蒂方程与复合生态系统的动力学机制,构建了大城市边缘区人居环境演变的阶段性、生命周期与可持续发展模型。揭示大城市边缘区人居环境系统演变的规律,可为大城市边缘区人居环境系统优化调控提供理论依据,充实人居环境科学理论体系。  相似文献   

基于规则的位置地图情境推理构建与实例分析     

汶博  齐晓飞  吴长枝  张帆 《地理信息世界》2017,(6):70-76

情境在移动位置服务领域起到融合多源时空数据、模拟地图使用情形及获取用户空间需求的作用。根据作者早期建立的位置地图情境模型,本文基于活动理论构建了位置地图情境三层推理规则,重点描述其基本原理与方法;通过形式化表达将情境推理的结果与位置地图表达联系起来,形成三层推理规则的解析与运行流程;以用户去机场登机为例,假设2种不同情形,验证5种情境事例。实验结果表明,本文的情境推理方法简洁、可操作性强,为进一步研究智能化地图服务提供参考和借鉴。  相似文献   

A heuristic cellular automata approach for modelling urban land-use change based on simulated annealing     

Yongjiu Feng 《International journal of geographical information science》2013,27(3):449-466

This article presents a novel cellular automata (CA) approach to simulate the spatio-temporal process of urban land-use change based on the simulated annealing (SA) algorithm. The SA algorithm enables dynamic optimisation of the CA's transition rules that would otherwise be difficult to configure using conventional mathematical methods. In this heuristic approach, an objective function is constructed based on a theoretical accumulative disagreement between the simulated land-use pattern and the actual land-use pattern derived from remotely sensed imagery. The function value that measures the mismatch between the actual and the simulated land-use patterns would be minimised randomly through the SA process. Hence, a set of attribution parameters that can be used in the CA model is achieved. An SA optimisation tool was developed using Matlab and incorporated into the cellular simulation in GIS to form an integrated SACA model. An application of the SACA model to simulate the spatio-temporal process of land-use change in Jinshan District of Shanghai Municipality, PR China, from 1992 to 2008 shows that this modelling approach is efficient and robust and can be used to reconstruct historical urban land-use patterns to assist with urban planning policy-making and actions. Comparison of the SACA model with a typical CA model based on a logistic regression method without the SA optimisation (also known as LogCA) shows that the SACA model generates better simulation results than the LogCA model, and the improvement of the SACA over the LogCA model is largely attributed to higher locational accuracy, a feature desirable in most spatially explicit simulations of geographical processes.  相似文献   

A new discovery of transition rules for cellular automata by using cuckoo search algorithm     

Min Cao  Quanfei Shen  Yanxia Wang 《International journal of geographical information science》2013,27(5):806-824

This paper presents an intelligent approach to discover transition rules for cellular automata (CA) by using cuckoo search (CS) algorithm. CS algorithm is a novel evolutionary search algorithm for solving optimization problems by simulating breeding behavior of parasitic cuckoos. Each cuckoo searches the best upper and lower thresholds for each attribute as a zone. When the zones of all attributes are connected by the operator ‘And’ and linked with a cell status value, one CS-based transition rule is formed by using the explicit expression of ‘if-then’. With two distinct advantages of efficient random walk of Lévy flights and balanced mixing, CS algorithm performs well in both local search and guaranteed global convergence. Furthermore, the CA model with transition rules derived by CS algorithm (CS-CA) has been applied to simulate the urban expansion of Nanjing City, China. The simulation produces encouraging results, in terms of numeric accuracy and spatial distribution, in agreement with the actual patterns. Preliminary results suggest that this CS approach is well suitable for discovering reliable transition rules. The model validation and comparison show that the CS-CA model gets a higher accuracy than NULL, BCO-CA, PSO-CA, and ACO-CA models. Simulation results demonstrate the feasibility and practicability of applying CS algorithm to discover transition rules of CA for simulating geographical systems.  相似文献   

柴达木周缘金属矿床成因类型、成矿规律与成矿系列   总被引：4，自引：0，他引：4  

丰成友  张德全  贾群子  李大新  闫升好  徐文艺  佘宏全 《西北地质》2012,45(1):1-8

位处青藏高原东北部、古亚洲构造域与特提斯构造域结合部位的柴达木盆地周缘地区,是一个具有复杂构造演化历史的多旋回复合造山区.同时,该区也是我国重要的、极富潜力的金属成矿带.在综合分析以往多年工作成果基础之上,较系统总结研究了区域成矿地质构造背景、区域构造演化、主要矿床类型、区域成矿规律与成矿系列.结果表明:该区地质构造演化主要经历了前寒武纪古陆形成、早古生代造山、晚古生代—早中生代造山和中新生代叠复造山等4个构造旋回.其中,早古生代和晚古生代—早中生代构造旋回与区内金属成矿关系密切;总结出6个主要矿床成因类型,分属于拉伸裂解构造背景的喷气-沉积矿床组合(包括VMS型、SEDEX型)和与造山过程有关的造山矿床组合(包括斑岩型、矽卡岩型、热液脉型、造山带型金矿等);该区成矿作用具有多期、多矿种和多类型的特点,初步总结划分出5个金属矿床成矿系列,即与新元古代—寒武纪裂解有关的铜多金属矿床成矿系列、与奥陶—志留纪裂解有关的铜钴铅锌多金属矿床成矿系列、与晚加里东陆-陆碰撞有关的金多金属矿床成矿系列、与晚古生代裂解有关的铜多金属矿床成矿系列、与晚华力西—印支期造山有关的铁铜铅锌金多金属矿床成矿系列.  相似文献   

基于语义网的地名本体服务框架研究     

梁汝鹏  李文娟  李勤超  姜海林 《测绘科学》2011,36(3):230-233

本文在总结地名本体的基本概念基础上,根据基于地理空间语义网的日常地理信息查询需要,进行了地名本体的概念设计.地名本体的设计可以分为两个阶段,第一阶段主要偏重于初级本体的设计,它主要支持地理对象的标示和检索等较为初级的任务.第二阶段将支持更多高级的任务,例如空间推理等.本文通过地名本体模型的构建,探讨了基于语义网的地名本...  相似文献