深水风浪的风区指数律     

管长龙  张淑芳  孙建  孙群 《中国海洋大学学报(自然科学版)》2004,34(5):704-712

对已有根据观测提出的幂函数形式风浪成长关系进行了分析。发现这些风浪成长关系在消去无因次风区后一致地与3／2指数律相协调，尽管它们原来存在较大的不协调性。发现Jeffreys，Sverdrup和Munk以及Platit的风能输入源函数在谱积分意义下具有相似性，而Tsikunov，Hasselmann和Phillips的破波耗散源函数在谱积分意义下也具有相似性，尽管这些源函数的原始形式和物理背景显著地不同。利用有效波能量平衡方程，将3／2指数律和发现的风能输入及破波耗散源函数相似性相结合，提出了深水风浪随风区成长的分式指数律，以得到的分式指数律拟合已有基于观测提出的风浪成长关系提出了半经验的风浪成长关系，与已有观测数据符合。  相似文献   

中国海岸侵蚀治理和海岸保护   总被引：5，自引：0，他引：5  

薛春汀 《海洋地质前沿》2002,18(2):6-9

加强海滩和海岸侵蚀的研究，组织建筑用砂资源的调查，进一步完善海洋环境保护法或制定海岸环境保护法以便制止不合理的采砂和保护沿岸单位和居民的合法权益，使出现环境问题后的赔偿有确定保证，防止人工海岩进一步扩大，发展偏僻海岸地区的发候旅游，让沿岩居民能从保护海岩中得到实际利益，以便使我国海岸侵蚀治理和海岸保护达到一个新水平。  相似文献   

Similarities of Some Wind Input and Dissipation Source Terms   总被引：1，自引：0，他引：1  

管长龙  孙建 《中国海洋工程》2004,18(4):629-642

Wind input parameterizations proposed by Jeffreys, Sverdrup and Munk, and Plant are analyzed. It is round by analogy that the similarity of integrals of the three wind input parameterizations exists. Wave breaking dissipation parmneterizations proposed by Tsikunov, Hasselmann, and Phillips are also analyzed. Likewise it is found by analogy that the similarity of integrals of the three dissipation parameterizations exists. The similarities of wind input and dissipation are applied to the investigation of the fetch-limited growth of wind waves, together with the 3/2 power law presented by Toba. Some semi-empirical formulas concerning the growth of wave height and period with fetch are presented. The results from the formulas are in good agreement with previous field observations.  相似文献   

Low T heat capacity measurements and new entropy data for titanite (sphene): implications for thermobarometry of high-pressure rocks     

M. R. F. Manon  E. Dachs  E. J. Essene 《Contributions to Mineralogy and Petrology》2008,156(6):709-720

The accepted standard state entropy of titanite (sphene) has been questioned in several recent studies, which suggested a revision from the literature value 129.3 ± 0.8 J/mol K to values in the range of 110–120 J/mol K. The heat capacity of titanite was therefore re-measured with a PPMS in the range 5 to 300 K and the standard entropy of titanite was calculated as 127.2 ± 0.2 J/mol K, much closer to the original data than the suggested revisions. Volume parameters for a modified Murgnahan equation of state: V _P,T  = V ₂₉₈° × [1 + a°(T − 298) − 20a°(T − 298)] × [1 – 4P/(K ₂₉₈ × (1 – 1.5 × 10⁻⁴ [T − 298]) + 4P)]^1/4 were fit to recent unit cell determinations at elevated pressures and temperatures, yielding the constants V ₂₉₈° = 5.568 J/bar, a° = 3.1 × 10⁻⁵ K⁻¹, and K = 1,100 kbar. The standard Gibbs free energy of formation of titanite, −2456.2 kJ/mol (∆H°_f = −2598.4 kJ/mol) was calculated from the new entropy and volume data combined with data from experimental reversals on the reaction, titanite + kyanite = anorthite + rutile. This value is 4–11 kJ/mol less negative than that obtained from experimental determinations of the enthalpy of formation, and it is slightly more negative than values given in internally consistent databases. The displacement of most calculated phase equilibria involving titanite is not large except for reactions with small ∆S. Re-calculated baric estimates for several metamorphic suites yield pressure differences on the order of 2 kbar in eclogites and 10 kbar for ultra-high pressure titanite-bearing assemblages.  相似文献   

乍得湖盆地构造特征与油气成藏规律初探   总被引：1，自引：1，他引：0  

黄先雄  夏斌  万志峰  吕宝凤  蔡周荣 《大地构造与成矿学》2008,32(3)

以前人的研究为基础,结合研究区及邻区地球物理资料、岩矿特征、钻井资料,分析了盆地结构特征、构造样式、演化序列以及油气成藏规律。研究表明,乍得湖盆地为伸展断-坳型裂谷盆地,断裂、褶皱构造发育;经历了前裂谷(侏罗纪以前)、同裂谷(135~23.5Ma)、后裂谷(23.5Ma以后)三个演化阶段;主要发育白垩纪和古近纪两套含油气系统。  相似文献   

提高线要素匹配率的动态化简方法     

陈竞男  钱海忠  王骁  何海威  胡慧明 《测绘学报》2016,45(4):486-493

矢量线要素匹配是当前空间数据匹配领域的研究焦点之一。本文提出了一种提高已有匹配算法正确率的线要素动态化简方法。首先,对待匹配双方利用开方根规律分别确定各自的化简阈值范围;其次,令化简参数在线要素各自的阈值范围内以一定的步长变化,对每条线要素分别进行化简,每完成一次化简,重新计算待匹配双方的匹配相似度,并与上一次化简后的匹配相似度进行比较,最终得到最高的匹配相似度值;最后,根据获取的最高匹配相似度来判断其是否成功匹配。该算法是一种以动态化简来带动动态匹配的过程。通过化简提取线要素主要形态,降低了局部细节对已有匹配算法的影响,从而提高了匹配正确率。试验验证及对比分析证明了本方法的科学性和普适性。  相似文献   

喀斯特发育机理与发展工程建设效应研究方向     

卢耀如 《地球学报》2016,37(4):419-432

喀斯特在中国分布广泛,更主要与经济发展、工程建设及人民日常生活具有密切关系,所以研究喀斯特发育规律,进而探索其对发展与工程产生的效应是非常重要的研究方向。本文在几十年开展这方面研究的成果上,综合探讨了:(1)区域性综合建设方面地质环境效应研究,包括岩溶区域性发育规律及长江、黄河大型工程的效应评判研究;(2)地下空间开拓方面,涉及城市地铁、高铁、地下大型建筑、矿山开采常发生的不良效应,及运用喀斯特水文地质等综合研究以评判危害性和开拓中的六个超前措施;(3)城镇群的发展与生态内涵的几个层次问题。通过这实例研究,强调水文地质、工程地质与环境地质在今后对实现中华强国梦的重要作用。  相似文献   

四川攀枝花小河流域地质灾害发育分布规律浅析     

李石桥  许俊豪  刘磊  曹亚廷  刘多林  计扬  叶小林  马启科 《地质灾害与环境保护》2016,(3):45-48

小河流域地处四川省攀枝花仁和区境内,地势南高北低,山脉走向近南北,岭谷相间。总体为中-大起伏中山地貌,较复杂的地形为滑坡、崩塌、泥石流的发生提供了空间,流域内地质灾害的发生一定程度影响了当地经济的发展。本文通过对区内23处地质灾害点的分析,讨论了流域地质灾害的主控因素及发育、分布规律,为科学合理地评价预测地质灾害的发展趋势与可能造成的危害提供参考资料。  相似文献   

单自由度陀螺寻北仪的运动规律分析     

郭金运  李成尧 《四川测绘》1995,18(2):57-61

根据傅科第一类回转仪的设想模型，本文用分析力学的方法研究了单自由度陀螺寻北仪的定向原理，分析了陀螺轴的运动规律，建立了多种因素如陀螺力矩，常阻尼力矩和空气阻尼等影响下的运动微分方程，分别求出对应解，并用小扰动理论研究了稳定性。  相似文献   

Implications of principal stress axes and eigenvalue ratios on critical orientation of fractures. Application to two tectonic regions in Alaska     

C. Caldentey  X. Lana 《Pure and Applied Geophysics》1990,133(1):87-102

The principal stress axes and eigenvalue ratios of the stress tensors from two active seismic regions in Alaska (eastern Aleutian Arc and eastern Gulf of Alaska) are computed. These results are obtained using focal mechanisms of earthquakes with magnitudes ranging from 5.5 to 8.2 and show for both regions slightly different compressional states with an orientation of the pressure axis of N26°W for the eastern Gulf of Alaska and N27°W for the east Aleutian Arc. The eigenvalue ratios for the eastern Gulf of Alaska and east Aleutian Arc are 0.84 and 0.99, respectively. The algorithm used in computations allows us to detect some focal mechanisms which are incoherent with respect to the obtained stress tensors. These incoherences are explained in terms of some tectonic features of the region. The orientations of possible pre-existing fractures which would need an unrealistically high maximum shear stress to start a slip on their fault planes are also investigated. These critical orientations depend on a constitutive frictional law as well as on eigenvalue ratios and eigenvectors of the stress tensors. The orientation, which is given in our case by the angle between the normal vector to a fracture and the regional tensional axis, is approximately 59° for the eastern Aleutian Arc. This angle ranges from 49° to 59° for the eastern Gulf of Alaska. It must be pointed out that fractures which need unrealistically high shear stress to start slip on their fault planes are defined by a very narrow band of possible angles between tensional direction and the normal vector to fault plane.  相似文献