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Mohammad Rezwanul Islam Syeda Fahliza Begum Yasushi Yamaguchi Katsuro Ogawa 《Journal of Marine Systems》2002,32(4):73
Remote sensing technique was applied to estimate suspended sediment concentration (SSC) and to understand transportation, distribution and deposition of suspended sediment in the estuary and throughout the coastal sea, off the Ganges–Brahmaputra River mouth. During low river discharge period, zone of turbidity maximum is inferred in the estuary near the shore. SSC map shows that maximum SSC reaches 1050 mg/l in this period. Magnitude of SSC is mainly owing to resuspension of the bottom surface sediments induced by tidal currents flowing over shallow water depths. The influence of depth on resuspension is farther revealed from the distribution and magnitude of SSC along the head of Swatch of No Ground (SNG) submarine canyon. During high river discharge period, huge river outflow pushed the salt wedge and flashes away the suspended sediments in the coastal sea off the river mouth. Zone of turbidity maximum is inferred in the coastal water approximately within 5–10 m depth of water, where the maximum SSC reaches 1700 mg/l. In this period, huge fluvial input of the suspended sediments including the resuspended bottom sediments and the particles remaining in suspension for longer period of time since their initial entry control mainly the magnitude of SSC. In the estuary near the shore, seasonal variation in the magnitude of SSC is not evident. In the coastal sea (>5 m water depth), seasonal influence in the magnitude of SSC could be concluded from the discrepancy between SSC values of two different seasons. Transportation and deposition of suspended sediments also experiences seasonal variations. At present, suspended sediments are being accumulated on the shallow shelf (between 5 and 10 m water depth) in low discharge period and on the mid-shelf (between 10 and 75 m water depth) during high discharge period. An empirical (exponential) relationship was found between gradual settle down of suspended sediments in the coastal sea and its lateral distance from the turbidity maximum. 相似文献
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选择性PDGF受体酪氨酸激酶抑制剂对兔PVR的治疗作用 总被引:1,自引:0,他引:1
目的 评价一种新的血小板源性生长因子 (platelet derivedgrowthfactor,PDGF)受体酪氨酸激酶抑制剂AG12 95对兔增殖性玻璃体视网膜病变 (proliferativevitreoretinopathy ,PVR)的治疗作用。 方法 兔结膜成纤维细胞 (rabbitconjunctivalfibroblastscells,RCF)培养 ,用MTT分析法检测PDGF AA和 BB以及AG12 95对兔RCF的增殖状况的影响。建立PVR动物模型 ,玻璃体腔内给予AG12 95 ,用牵引性视网膜脱离 (tractionalretinaldetach ment,TRD)的发生率判断药物的体内疗效。眼视网膜电生理检查和HE染色分析药物的毒性。结果 10 μmol·L-1和 10 0 μmol·L-1两种浓度的AG12 95均可显著抑制由PDGF AA和 BB诱导的成纤维细胞的增生 ,10 0 μmol·L-1AG12 95可减缓兔TRD的发生 ,但其作用仅持续至第 2 1d。在AG12 95治疗组中 ,未发现明显的网膜毒性。结论 PDGF受体酪氨酸激酶抑制剂AG12 95可减缓兔TRD的发生。 相似文献
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Budi S. Prasodjo Kimio Saito Yasushi Higo Hisashi Nobukawa Katsuya Maeda 《Journal of Marine Science and Technology》2006,11(4):260-269
This article discusses the dynamic responses of a coastal cargo ship that consists of unit modules with advance forward speed
in waves. We introduce a simple way of connecting the modules that has enough capability to link the modular parts of the
ship as a unified whole. The flexible connection consists of male and female rubber fenders with additional pretensioned ropes.
This kind of connection system is proposed for use in coastal regions with relatively calm waters wherein the modular ship
can move at a moderate speed. The modules are assumed to be rigid compared to the connections. Computations were performed
to investigate the vertical elastic responses of four modules connected end-to-end with the assumption that in the simple
hinge, no gaps occur in the flexible rubber connections between adjacent modules. A simple method, which is an extension of
the computational analysis we reported previously, is presented to study the hydroelasticity and rope tension forces of the
modular ship with forward speed in waves. Experiments with a three-dimensional model at Froude numbers of 0 and 0.16 in head
waves were performed to evaluate the effectiveness of the calculation method. In the experiments, deflections for each part
were measured using calibrated potentiometers. Force transducers were used to measure the rope tension force between the modules
of the articulated cargo ship. Some slight differences were observed, but generally the calculated results showed the same
trends as the experimental values. 相似文献
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Yoichi Sumi Hiroshi Yajima Masahiro Toyosada Takao Yoshikawa Shuji Aihara Koji Gotoh Yoshitaka Ogawa Toshiyuki Matsumoto Kazuhiro Hirota Hideyuki Hirasawa Masanobu Toyoda Yasushi Morikage 《Journal of Marine Science and Technology》2013,18(4):497-514
The rapid enlargement of the size of container ships has led to the application of extremely thick plate in the deck structures, which may grow concerns about the fracture toughness at the butt-weld with large amount of heat input, and the arrest toughness of brittle crack propagation in the base metal of such thick plates. Also, slam-induced whipping stresses might affect the fatigue crack propagation and the initiation of a brittle crack in a container ship. In order to prevent the catastrophic failure of deck structures by brittle fracture, national joint research projects, which focused on the safety-related issues of extremely thick steel plate applied to hull of large container ships, were formed from April 2007 to March 2011 organized by the Japan Ship Technology Research Association (JSTRA) supported by the Japanese Government in collaboration with universities, national research institute, classification societies and relevant industries including shipbuilding, steel manufacturing and shipping companies. The joint research projects have carried out the investigations on crack initiation toughness of the weld, fatigue crack propagation under seaway loading, the potential of defect detection by ultrasonic testing, and the crack-arrest methods after brittle crack propagation. Practical recommendations to prevent brittle fracture of large container ships were proposed based on these comprehensive investigations. The essential parts of the above research activities are presented in this paper. 相似文献
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The Molikpaq is a steel mobile arctic structure which has been used for exploration of hydrocarbon reserves on the Canadian
Beaufort shelf. In early 1986, the Molikpaq experienced numerous interactions with various ice features at Amanuligak I-65.
An extensive ice loads investigation program was conducted as a joint industrial project. Ishikawajima-Harima Heary Industries
(IHI) has proposed a method to estimate the global ice load on an arctic structure by utilizing results from ice tank experiments.
Experiments were conducted in the IHI ice model tank using a model of the Molikpaq. A comparison between the measured ice
loads and the estimated ice loads was made and it was found to be in fair agreement, in spite of some uncertainties involved
in both the measured and the estimated ice loads. In this paper, instrumentation which the Molikpaq employed in the investigation
program is briefly introduced. Failure modes of ice features observed in the program are also mentioned. The basic idea behind
the dual parameters testing and estimating method (DuPTEM) is described. The model experiments and the results are then outlined.
The comparison between the measured and estimated ice loads is shown. Finally, uncertainties in both the estimated and the
measured ice loads are discussed. 相似文献
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Michio Ueno Hideki Miyazaki Harukuni Taguchi Yasushi Kitagawa Yoshiaki Tsukada 《Journal of Marine Science and Technology》2013,18(2):192-202
A model scale experiment at a new basin reproduced a phenomenon occurring for a fast ferry; large roll motion and subsequent cargo shift in a quartering sea. Wave generators surrounding the whole periphery of the basin realized a designated directional sea. A carriage system tracked a free-running model ship and a movable weight simulated the cargo shift. Measuring the directional wave field in the basin confirmed the all-around wave generator successfully reproduced the intended wave field that was estimated for the location and the time of the incident. The encounter wave spectrum analyzed using measured data agree well with the theoretically predicted one. The reproduced ship motion, triggered by a small concentrating wave, tells how the ship responded in the successive large quartering waves and the validity of the procedure to reproduce the incident. Repeated measurements of the model ship’s extreme motion confirm a high repeatability of the experiment. 相似文献
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