沉入式大圆筒结构码头工作机理离心模型试验研究   总被引：6，自引：0，他引：6  

徐光明  章为民等 《海洋工程》2001,19(1):38-44

沉入式大圆筒结构码头，由于筒体下部有一定长度嵌入港地泥面以下的地基土层中，因此，其工作机理不仅不同于其它挡土岸壁式码头，而且也有别于基床式大圆铜结构码头。本文介绍了用土工物理离心试验对这一结构形式码头工作机理所作的研究，就沉入式大圆的深高比、径高比和筒壁摩擦作用对工作性状影响规律进行了初步研究，另外还尝试测定了大圆筒侧壁土压力分布规律，并探讨了码头面沉降发展趋势特征。  相似文献   

等幅疲劳三参数P—S—N曲线族最优拟合法   总被引：2，自引：0，他引：2  

匡卫红  倪侃等 《海洋工程》2002,20(2):74-77

对于给定的等幅疲劳成组试验数据 ,利用三参数幂函数方程来描述P -S -N等幅曲线。通过线性拟合相关系数的最优化来确定其中三个系数 ,采用割线法进行最优化求解。该方法具有迭代收敛快、拟合精度高的特点  相似文献   

Sea-surface acoustic backscattering measurement at 6–25 kHz in the Yellow Sea     

戚乐华  阚光明  刘保华  裴彦良  杨志国  于盛齐 《海洋学报(英文版)》2020,39(3):113-122

Sea-surface acoustic backscattering measurements at moderate to high frequencies were performed in the shallow water of the south Yellow Sea, using omnidirectional spherical sources and omnidirectional hydrophones. Sea-surface backscattering data for frequencies in the 6–25 k Hz range and wind speeds of(3.0±0.5)and(4.5±1.0) m/s were obtained from two adjacent experimental sites, respectively. Computation of sea-surface backscattering strength using bistatic transducer is described. Finally, we calculated sea-surface backscattering strengths at grazing angles in the range of 16°–85°. We find that the measured backscattering strengths agree reasonably well with those predicted by using second order small-roughness perturbation approximation method with "PM" roughness spectrum for all frequencies at grazing angles ranged from 40° to 80°. The backscattering strengths varied slightly at grazing angles of 16°–40°, and were much stronger than roughness scattering. It is speculated that scattering from bubbles dominates the backscattering strengths at high wind speeds and small grazing angles. At the same frequencies and moderate to high grazing angles, the results show that the backscattering strengths at a wind speed of(4.5±1.0) m/s were approximately 5 d B higher than those at a wind speed of(3.0±0.5) m/s. However, the discrepancies of backscattering strength at low grazing angles were more than 10 d B. Furthermore the backscattering strengths exhibited no significant frequency dependence at 3 m/s wind speed. At a wind speed of 4.5 m/s, the scattering strengths increased at low grazing angles but decreased at high grazing angles with increasing grazing angle.  相似文献   

和田泉水涌出量的混沌特性分析与预测     

张高锋  宁立强  罗光明  张梦花  王权 《地下水》2007,29(4):20-22,35

应用功率谱分析及混沌理论对和田 12 号泉水涌出量进行判定分析,结果表明该泉水的流量具有混沌特性.并在此基础上,应用改进的最大 Lyapunov 指数模型对该泉水流量进行了预测,取得了比较理想的效果,为研究及合理利用该地区地下水资源提供了新的依据.  相似文献   

不同发展阶段台风大气边界层暖区变化特征     

刘学刚  罗哲贤  滕代高  代刊 《南京气象学院学报》2007,30(3):320-327

采用NCEP/NCAR全球对流层1°×1°再分析格点资料,选取6个登陆台风个例,分析了不同发展阶段台风大气边界层暖区变化的特征及其与强度变化的关系.结果表明:在台风的不同发展阶段,其大气边界层相对涡度场和温度场的结构有着明显的不同特征,暖中心与正涡中心的距离与台风强度为反相关关系,暖中心与正涡中心的距离越小,台风强度越强.  相似文献   

Late Triassic granitoids of the eastern margin of the Tibetan Plateau: Geochronology, petrogenesis and implications for tectonic evolution   总被引：7，自引：0，他引：7  

L. Xiao  H.F. Zhang  J.D. Clemens  Q.W. Wang  Z.Z. Kan  K.M. Wang  P.Z. Ni  X.M. Liu 《Lithos》2007,96(3-4):436-452

Late Triassic granitoids in the Songpan-Garzê Fold Belt (SGFB), on the eastern margin of the Tibetan Plateau, formed at 230 to 220 Ma and can be divided into two groups. Group 1 are high-K calc-alkaline rocks with adakitic affinities (K-adakites), with Sr > 400 ppm, Y < 11 ppm, strongly fractionated REE patterns ((La/Yb)_N = 32–105) and high K₂O/Na₂O (≈ 1). Group 2 are ordinary high-K calc-alkaline I-types with lower Sr (< 400 ppm), higher Y (> 18 ppm) and weakly fractionated REE patterns ((La/Yb)_N < 20). Rocks of both groups have similar negative Eu anomalies (Eu/Eu = 0.50 to 0.94) and initial ⁸⁷Sr/⁸⁶Sr (0.70528 to 0.71086), but group 1 rocks have higher ε_Nd(t) (− 1.01 to − 4.84) than group 2 (− 3.11 to − 6.71). Calculated initial Pb isotope ratios for both groups are: ²⁰⁶Pb/²⁰⁴Pb = 18.343 to 18.627, ²⁰⁷Pb/²⁰⁴Pb = 15.610 to 15.705 and ²⁰⁸Pb/²⁰⁴Pb = 38.269 to 3759. Group 1 magmas were derived through partial melting of thickened and then delaminated TTG-type, eclogitic lower crust, with some contribution from juvenile enriched mantle melts. Group 2 magmas were generated by partial melting of shallower lower crustal rocks. The inferred magma sources of both groups suggest that the basement of the SGFB was similar to the exposed Kangding Complex, and that the SGFB was formed in a similar manner to the South China basement. Here, passive margin crust was greatly thickened and then delaminated, all within a very short time interval ( 20 Myr). Such post-collisional crustal thickening could be the tectonic setting for the generation of many adakitic magmas, especially where there is no spatial and temporal association with subduction.  相似文献   

PRECIS模式对宁夏气候变化情景的模拟分析^*   总被引：2，自引：0，他引：2  

陈楠  许吟隆  陈晓光  杨侃  张勇 《第四纪研究》2007,27(3):332-338

使用英国Hadley气候中心区域气候模式PRECIS,分析了B2温室气体排放情景下,相对于气候基准时段1961~1990年宁夏2071~2100年(2080s)地面气温、降水量等的变化。结果表明:PRECIS模式能够很好地模拟宁夏气温的分布特征,对夏季最高气温的模拟效果好于冬季最低气温;较好地模拟出了宁夏降水南多北少的空间差异特征,且对夏季降水的模拟能力明显强于年均降水和冬季降水。相对于气候基准时段, 在B2情景下,2080s宁夏年平均、冬季和夏季平均气温均明显上升,宁夏北部和南部的部分地区气温上升幅度最大,夏季平均气温和最高气温上升幅度大于冬季平均气温和最低气温;未来宁夏年、冬季和夏季平均降水较基准时段均有所增加,但降水随年代际却呈减少趋势,由于气温和降水的气候变率加大,2080s宁夏出现高温、干旱、洪涝等异常天气事件的可能性增大。  相似文献   

华南沿海近100年气温上升速率估算   总被引：11，自引：42，他引：11  

陈特固  曾侠  钱光明  赵美霞  余克服 《广东气象》2006,(3):1-5

采用华南沿海气象站气温资料,在排除城市热岛效应的基础上,分析近50年、近100年地表气温的变化趋势,得出华南沿海近51年(1953~2003年)的平均增温速率为0.12℃/10年,近100年(1905~2004年)的增温速率为0.6~0.8℃/100年,均与同时期的北半球(陆地 海面)平均增温速率相近。  相似文献   

上海地震台阵标定结果研究     

于海英  朱元清  阚道玲  赵书礼 《中国地震》2006,22(2):190-196

本文阐述了地震台阵标定理论和上海地震台阵的标定方法，并对上海台阵标定结果进行了分析：给出2个典型地震的台阵标定结果；对日本北海道地区和本州地区的地震标定差别进行了研究；研究了不同方向、不同震中距和不同震级的地震标定结果。讨论结果表明，上海地震台阵标定显著提高了定位的精度。  相似文献   

郯庐断裂与金矿成矿   总被引：4，自引：0，他引：4  

沈远超  曾庆栋  刘铁兵  李光明  申萍  孙秀英 《世界地质》2003,22(1):41-44

郯庐断裂带是我国东部规模巨大的北东向断裂构造系，长约2500km。南起庐江至郯城，经渤海向北，分成伊兰-舒兰断裂和敦化-密山断裂。不同区域、不同时代具有不同特征。郯庐断裂控制了许多大型、中型和小型金矿分布，是中国最大的金矿成矿带。  相似文献