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111.
112.
The sway, heave and roll added masses of three uniform cylinders with semi-circular, rectangular and triangular cross-sectional shapes in shallow and narrow water are numerically analysed. The method is based on simulation of the potential flow induced by the cylinder's mode of motion. The effects of shallow and narrow water on added mass are analysed and presented. It is concluded that the shallow and narrow water effects on added mass depend on the different cross-section shapes of the cylinders. In particular, the water depth effect on sway added mass is stronger than that on heave added mass while the narrow water effect on sway is weaker than that on heave. The shallow water effect on added mass tends to weaken the narrow water effect. Lastly the effect of shallow and narrow water on added mass on a rectangular cylinder is the strongest while that on a triangular cylinder is the weakest. 相似文献
113.
海洋数字图书馆建设概论 总被引:1,自引:1,他引:1
本文在探讨数字图书馆建设关键技术的基础上,从图书馆门户网站、海洋特色数字化资源、海洋文献检索服务系统和图书馆自动化系统建设等方面,概述了海洋数字图书馆建设的实践,以推动海洋图书馆的进一步发展。 相似文献
114.
南极布兰斯菲尔德海峡表层沉积物的酸解烃 总被引:1,自引:0,他引:1
本文研究了南极布兰斯菲尔德海峡表层沉积物的酸解烃分布特征,并佐以热释汞和蚀变碳酸盐的分析。从酸解烃中甲烷含量的低值和C1/(C2+C3)比值,以及乙烯的存在等判断,布兰斯菲尔德海峡沉积物的烃类气体来自于生物成因。 相似文献
115.
非常规管节点疲劳寿命分析与计算 总被引:6,自引:1,他引:6
对非常规管节点的疲劳寿命进行了分析研究,用SESAM计算疲劳载荷,应用精细有限元分析计算热点应力,用规范的S—N曲线计算管节点的疲劳寿命。通过实例计算表明,这些处理对非常规管节点疲劳寿命分析与计算是很有效的。 相似文献
116.
117.
董胜 《中国海洋大学学报(自然科学版)》1997,(2)
针对海上矿石运输,介绍了一种完成定量任务并能使投资费用最少为目标的最优船队组建方法,同时对易变参数进行了灵敏度分析,使决策更加科学化 相似文献
118.
Shipborne GPS attitude determination during MMST-93 总被引:1,自引:0,他引:1
Lachapelle G. Cannon M.E. Lu G. Loncarevic B. 《Oceanic Engineering, IEEE Journal of》1996,21(1):100-104
The attitude parameters of a ship underway were measured using a configuration of four 10-channel NovAtel Model 951 narrow-correlator-spacing receivers. These C/A code receivers have output rates of up to 10 Hz and maintain effective carrier phase lock under relatively harsh ship dynamics. The attitude parameters are calculated independently at each epoch using differential carrier phase measurements, carrier phase ambiguities are resolved on-the-fly by constraining the approximately known distances between the antennas that are rigidly mounted on the ship. Carrier phase thermal noise and multipath are minimized by mounting the antennas as far apart as possible. The four-antenna configuration provides redundancy and further improves accuracy. During the Matthew Motion Sensor Trials (MMST-93) conducted off the coast of Halifax, Nova Scotia, in June-July 1993, the GPS-derived attitude parameters were compared with those obtained with a Honeywell HG1050 ring laser gyro inertial navigation system (INS) which provides roll and pitch with an accuracy of 15 arcsecs and heading with an accuracy of 2 arcmins. To simulate rough weather conditions, sharp maneuvers were performed to induce roll angles in excess of 10°. No accuracy degradation nor any loss of GPS measurements occurred. The RMS agreement between GPS and INS derived attitude parameters is better than 2 arcmins in heading, 1 arcmin in pitch and 3 arcmins in roll. This level of accuracy demonstrates the capability of GPS for cost-effective shipborne attitude determination at an accuracy level of 0.05 相似文献
119.
1975-1976年,中国科学院海洋研究所东海大陆架调查时,在底栖生物采泥取样中获得3个小单売标本;经鉴定,认为是马蹄螺总科(Trochacea)、蝾螺科(Turbinidac)、缩口螺属(Collonia)中的一个新种。标本存中国科学院海洋研究所。 相似文献
120.
A Preliminary Study of Shear Wave in Seafloor Surface Sediments 总被引:1,自引:0,他引:1
This article preliminarily reports and analyses the transmission characteristics and behaviors of shear wave in the offshore seafloor surface sediments in China, discusses the relationships between the physical and mechanical features of the shear wave and the compression wave, and compares the testing results with that of Hamilton and Chen et al. The result shows that the shear wave can be tested if the seafloor surface sediment has tangent modulus. The shear wave velocity ranges from 50-600 m/s and the measuring frequency from 50-200 kHz. The sound velocity rate of shear wave and compression wave can be used to appraise the stress-strain feature of seafloor surface sediments. This study provides a basis for further describing and appraising the seafloor sedimentary acoustic-mechanical feature and building a geological-acoustic model on China's offshore sea area. 相似文献