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91.
详细的地球化学研究表明,新疆北部富蕴县沙尔布拉克中泥盆统北塔山组的辉石安山岩具有中等的SiO2含量(52.13%-60.45%);高MgO(3.91%-9.31%)和相容元素(包括Ni、Cr、Co等)含量,以及高Mg^#和Al2O3/TiO2比值;低TiO2含量(0.21%-0.35%);同时具有U型稀土元素分布模式;并强烈亏损高场强元素。这些特征均与玻安岩的地球化学特征一致,应属于玻安岩,形成于前弧环境。沙尔布拉克玻安岩的存在表明,古亚洲洋在早-中泥盆世向南发生了洋壳俯冲作用。  相似文献   
92.
2001年11月14日新疆-青海8.1级特大地震,是1951年当雄8.0级特大地震后,整整50年大陆上首发8级特大地震,它的发生虽然没有造成较大经济损失和人员伤亡,但它的科学意义和学术价值超过过去几十年来任何一次强震,它打破了我们对地震活跃期的划分和许多传统认识,同时对如何判断未来地震大形势提出了重大课题。  相似文献   
93.
内蒙古中西部地区震源参数研究   总被引:1,自引:1,他引:0  
选取内蒙古测震台网2009—2016年内蒙古中西部ML≥2.8中小地震波形记录,采用多台联合反演方法,计算该区中小地震震源谱参数,获得地震矩M0、矩震级MW、应力降Δσ和震源尺度r,利用线性回归,分析近震震级ML、地震矩M0、矩震级MW、应力降Δσ和震源尺度r之间的关系。结果表明,各参数之间存在一定线性关系,内蒙古中西部地区应力降模型为增加应力降模型(ISD)。  相似文献   
94.
在野外地质调查的基础上,对新疆东准噶尔南明东金矿床的矿床地质特征、成因类型、控矿因素、找矿标志以及下一步找矿方向进行了综合研究,认为该矿床为中低温热液蚀变岩型金矿床,受韧-脆性剪切带、地层建造和热液活动的多重控制。矿区地质环境复杂,地表蚀变带规模较大,深部尚未完全控制,具有较好的找矿前景。南明水组的层间断裂、褶皱交汇部位是成矿的有利地段。  相似文献   
95.
新疆县域产业结构转换能力综合评价   总被引:13,自引:1,他引:12  
产业结构的演进和转换是经济发展的本质特征,也是促进经济持续稳定协调发展的关键。文章从影响区域产业结构转换的技术创新能力、需求能力、供给能力、对外贸易发展、经济政策等因素出发,从5个方面构建了由13个指标组成的区域产业结构转换能力评价指标体系,并在此基础上采用主成分分析、层次分析和均方差3种方法的组合评价法对新疆县域产业结构转换能力进行研究,并提出相应建议。  相似文献   
96.
Traditionally autonomous underwater vehicles (AUVs) have been built with a torpedo-like shape. This common shaping is hydrodynamically suboptimal for those AUVs required to operate at snorkeling condition near the free surface. In this case, the wave resistance associated to the wavy deformation of the sea surface induced by the motion of the platform is an important component of the drag. This work has investigated the optimum hull shape of an underwater vehicle moving near the free surface. Specifically a first-order Rankine panel method has been implemented to compute the wave resistance on a body of revolution moving close to the free surface. A simulated annealing algorithm was then employed to search those set of parameters defining the hull shape that minimize the wave resistance. The optimization was constrained to keep constant the total volume of the vehicle. The total drag of scaled models of the torpedo-like and resulting optimum shapes was measured in the naval tank of the University of Trieste. Measurements showed a smaller resistance of the optimized shape in the range of the considered Froude numbers.  相似文献   
97.
The paper describes the current developments of a class of low-cost, light-weight autonomous underwater vehicles for coastal oceanographic applications; the vehicle class is named Fòlaga, the Italian name of an aquatic bird that swims on the water surface and dives to catch fish. The main design characteristics of the most recent vehicle of the class, the Fòlaga III, are reviewed. Navigation and control system design are discussed, with particular attention to the diving phase, which is accomplished as in oceanographic gliders by varying the vehicle buoyancy and attitude. Experimental results show that the PID robust controllers implemented are effective in the diving control phase. Finally, a distributed cooperation algorithm to be applied by a team of Fòlaga-like vehicles in adaptive oceanographic sampling applications is described. The algorithm optimizes area coverage while taking into account the accuracy in the reconstruction of the oceanographic field and inter-vehicle communication through a range constraint. The resulting dynamic programming algorithm can be implemented in a distributed fashion among the team components.  相似文献   
98.
The Korea Ocean Research and Development Institute (KORDI) has developed a small AUV named ISiMI. The mission of ISiMI is to work as a test-bed AUV for the development and validation of various algorithms and instruments required to enhance the AUV's functions. The design concept of ISiMI is that of a vehicle small enough to cruise the Ocean Engineering Basin (OEB) of KORDI and to be handled by one or two people. The downsized design and the cruising ability in its tank enable fast experimental feedback on AUV technologies and a shorter development period for new technologies. This paper presents a review of our research work on the development of ISiMI, with a performance evaluation by simulation and an experimental test. After the design and implementation of ISiMI, including its positioning system in the OEB, are presented, a series of test results in the OEB and discussions of the results are presented, with comparisons of the simulation and experimental outputs.  相似文献   
99.
This paper discusses control strategies adapted for practical implementation and efficient motion of autonomous underwater vehicles (AUVs). For AUVs we would like efficiency in both the measured time and the energy consumption, the mission dictating the weight to put on each of these cost. As a first approach to this problem, we focus in this paper on time minimization. Based on the structure of the time optimal trajectories and of the pure motions, we develop an algorithm to design time efficient trajectories corresponding to piecewise constant thrust arcs with few actuator switchings. We do that by solving a new optimization problem where the unknowns are the time period between two actuator switchings as well as the values of the constant thrust arcs. We apply a direct method to compute the solutions numerically. With our algorithm, we gain considerable computational time. Moreover, with as few as three actuator switchings, the duration of our trajectories is within 10% of the optimal trajectories. Since our control strategies have a simple structure they can be implemented on a test-bed vehicle. For the experiments displayed in this paper we use a spherical underwater vehicle which exhibits with almost no preference of direction or orientation for movement; this gives us a very controllable and versatile vehicle.  相似文献   
100.
在内蒙古东部喀喇沁地区早中生代大营子闪长岩中首次发现基性麻粒岩捕虏体.初步研究表明它们不同于华北克拉通地表出露的前寒武纪麻粒岩.根据其主要造岩矿物斜方辉石、单斜辉石、黑云母及斜长石的电子探针分析结果, 重点研究了各主要造岩矿物的化学成分特点, 并讨论了麻粒岩捕虏体的变质作用温压条件.研究结果表明, 捕虏体岩石的变质作用已达麻粒岩相, 其变质作用条件约为850~900 ℃, 0.6~1.0 GPa.这些麻粒岩捕虏体反映了研究区早中生代下地壳的组成特点, 为恢复该区早中生代深部地壳结构提供了依据.   相似文献   
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