Dynamic responses under the excitation of pulse sequences   总被引：6，自引：3，他引：3  

戴君武  Mai Tong  George C.Lee  齐霄斋  白文婷 《地震工程与工程振动(英文版)》2004,3(2):157-169

This paper studies the dynamic responses of SDOF system under pulse-dominant excitations. The purpose of the study is to prepare for scrutiny of some near-field pulse-dominant ground motions and their potential to cause structural damage. Extending the single pulse dynamics, we consider the effect of pulse sequences. This kind of excitation was particularly obvious in some of previous earthquakes such as Northridge (1994) and Chi-Chi (1995). Based on the duration,peak and rise and decay era of the main pulse as well as its relationship with the predecessor and successor pulses, we propose a classification for the pulse sequences. Consequent studies have been carried out for acceleration, velocity and displacement response spectra of the main pulse with either a predecessor or a successor pulse. The analysis also includes general response behaviors in different fundamental period segments and special aspects of response at certain points (e.g., the corresponding peak points).  相似文献   

Bayesian inference of kinematic earthquake rupture parameters through fitting of strong motion data     

D. Monelli  P. M. Mai 《Geophysical Journal International》2008,173(1):220-232

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Effects of dietary β-glucan and glycyrrhizin on non-specific immunity and disease resistance of the sea cucumber (<Emphasis Type="Italic">Apostichopus japonicus</Emphasis> Selenka) challenged with <Emphasis Type="Italic">Vibrio splendidus</Emphasis>     

Jie Chang  Wenbing Zhang  Kangsen Mai  Hongming Ma  Wei Xu 《中国海洋大学学报(英文版)》2010,9(4):389-394

Sea cucumbers, Apostichopus japonicus Selenka, were fed diets containing non-immunostimulant (basal diet), 0.2% β-glucan and 0.02% glycyrrhizin in a recirculatory water system for 45 days, and subsequently challenged with Vibrio splendidus by injection at 1.0×10⁸ cfu / sea cucumber for 15 days. Phagocytic capacity (PC), intracellular superoxide anion production (ISAP), lysozyme (LSZ) activity and superoxide dismutase (SOD) activity in the coelomic fluid were analyzed on the 0^th, 5^th, 10^th and 15^th days after injection. Results showed that after the 45-day feeding period, PC, ISAP, LSZ activity and SOD activity in sea cucumbers fed with dietary β-glucan or glycyrrhizin were significantly higher than in those fed with the basal diet. On the 5th day after infection, all the immune parameters examined in the sea cucumbers injected with V. splendidus decreased in value significantly. On the 15^th day, PC, ISAP and LSZ activity returned to levels similar to those on the 0^th day. For the sea cucumbers injected with saline, there were no significant differences in all the immune parameters examined and in the cumulative morbidity during the 15-day challenging trial. After injecting with V. splendidus, the cumulative morbidity of sea cucumbers fed with the basal diet was significantly higher than those fed with dietary β-glucan or glycyrrhizin when challenged with V. splendidus challenged sea cucumber fed with the basal diet was significantly higher than those fed with dietary β-glucan or glycyrrhizin. There was no significant difference in cumulative morbidity between the dietary β-glucan and glycyrrhizin treatments over time.  相似文献   

Enhancement of Seismic Data Processing and Interpretation of Fracture Zones on the Upper Part of Granitic Basement in Cuu Long Basin,Vietnam     

Mai Thanh Tan  Mai Thanh Ha  Kurt J. Marfurt  Nguyen Trung Hieu  Nguyen Thi My Hanh 《Acta Geophysica》2016,64(6):2214-2231

The fractured granite basement is the primary oil and gas reservoir in the Cuu Long Basin, Vietnam. Due to the complexity of this nonlayered unconventional target, combined with complicated fault and fracture systems, the seismic data quality near and within the basement section is very low. For this reason, it is important to apply improved seismic data processing workflows, filtering and migration techniques, as wells as attribute processing methods to enhance the imaging quality.Our studies show that applying different types of filters, including the f-k, Radon transform and Tau-P, improves signal to noise ratio, removing multiples, revealing basement’s top and its related fractured and fault zones. In addition, the application of multi-arrival-solution migration algorithms, such as Kirchhoff Migration and Controlled Beam Migration, provides improved imaging for identifying basement top and faults and fractures within the basement. Furthermore, the application of seismic attributes such as curvature, apparent dip, or energy gradient, is important in locating faults and fractures, whereas mapping of intensity and orientation of such structures assists the delineation of “sweet spots” and assists the planning of exploration.  相似文献   

An analysis of coastal erosion in the tropical rapid accretion delta of the Red River, Vietnam     

Do Minh Duc  Mai Trong NhuanChu Van Ngoi 《Journal of Asian Earth Sciences》2012,43(1):98-109

The largest plain in the North Vietnam has formed by the redundant sediment of the Red River system. Sediment supply is not equally distributed, causing erosion in some places. The paper analyzes the evolvement and physical mechanism of the erosion. The overlay of five recent topographical maps (1930, 1965, 1985, 1995, and 2001) shows that sediment redundantly deposits at some big river mouths (Ba Lat, Lach, and Day), leading to rapid accretion (up to 100 m/y). Typical mechanism of delta propagation is forming and connecting sand bars in front of the mouths. Erosion coasts are distributed either between the river mouths (Hai Hau) or nearby them (Giao Long, Giao Phong, and Nghia Phuc). The evolvement of erosion is caused by wave-induced longshore southwestward sediment transport. Meanwhile sediment from the river mouths is not directed to deposit nearshore. The development of sand bars can intensively reduce the erosion rate nearby river mouths. Erosion in Hai Hau is accelerated by sea level rise and upstream dams. Sea dike stability is seriously threatened by erosion-induced lowering of beach profiles, sea level rise, typhoon, and storm surge.  相似文献   

Influence of dietary probiotic Bacillus TC22 and Prebiotic fructooligosaccharide on growth, immune responses and disease resistance against Vibrio splendidus infection in sea cucumber Apostichopus japonicus     

Yancui Zhao  Kangsen Mai  Wei Xu  Wenbing Zhang  Qinghui Ai  Yanjiao Zhang  Xiaojie Wang  Zhiguo Liufu 《中国海洋大学学报(英文版)》2011,10(3):293-300

The effects of probiotic Bacillus TC22 (isolated from intestine of infected sea cucumber) and prebiotic fructooligosaccharide (FOS) on growth, immunity and disease resistance in sea cucumber Apostichopus japonicus were studied. Six experimental diets were formulated with combinations of three levels of TC22 (0, 107 and 109 CFU g-1 diet) and two levels of FOS (0 and 0.5%) in a 3 × 2 factorial experiment. At the end of the 8-week feeding trial,animals were challenged by injecting Vibrio splendidus. The results revealed that the specific growth rates (SGR) of sea cucumbers were not affected by TC22 and FOS, or the interaction between TC22 and FOS (P > 0.05). However,there were significant interactions between TC22 and FOS for immune response and disease resistance in sea cucumbers (P < 0.05). When sea cucumbers were fed with TC22 at 109 CFU g?1 feed and 0.5% FOS alone or in combination, the phagocytosis, respiratory burst and phenoloxidase activity of sea cucumber coelomocytes were significantly enhanced;the disease resistance against V. splendidus infection was also increased significantly (P < 0.05).However, dietary combination of TC22 at 109 CFU g-1 diet and 0.5% FOS did not yield significantly higher efficiency than either TC22 at 109 CFU g-1 diet or 0.5% FOS used alone (P > 0.05). Therefore, further studies should examine the effects of combinations of other levels of FOS(> 0.5% or < 0.5%) and TC22 on the immunity and disease resistance of sea cucumbers.  相似文献   

Diatom quantification and their distribution with salinity brines in coastal sediments of Terra Nova Bay (Antarctica)     

Baldi F  Facca C  Marchetto D  Nguyen TN  Spurio R 《Marine environmental research》2011,71(4):304-311

Benthic diatoms represent an important element of global nutritional productivity; to raise attention on their role, which is often neglected due to analytical difficulties, surface (1 cm top layer) coastal sediments from Gerlache inlet to Penguin Bay at Terra Nova Bay were collected and stored at -20 °C. DNA amplification by real-time PCR, based on diatom-specific oligonucleotide primers designed on small-subunit rRNA (SSU rRNA), was performed in addition to diatom conventional cell counting and spectrophotometric determination of photo-pigments. Moreover, cations and anions were determined in sediments with the aim to identify factors involved in the control of diatom abundance. Diatom distribution was found quite heterogeneous displaying significant differences from site to site. The salinity in sediments ranged from 45.1 at Gerlache inlet to 76.2 at Penguin Bay and it was correlated with cell abundance, biodiversity, amount of pigments and amplified DNA. The dominant species, Fragilariopsis curta, was associated to sediment salinity brines.  相似文献   

Tracing sewage pollution in the Pearl River Delta and its adjacent coastal area of South China Sea using linear alkylbenzenes (LABs)   总被引：4，自引：1，他引：3  

Luo XJ  Chen SJ  Ni HG  Yu M  Mai BX 《Marine pollution bulletin》2008,56(1):158-162

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The oldest tylosaurine mosasaur (Reptilia; Lacertilia) from the Late Cretaceous of Belgium: Hermann von Meyer (1860) revisited     

Mulder  Eric W.A.  Mai  Hartmut 《Geologie en Mijnbouw》1999,78(2):207-213

A mosasaurid parietal from the Late Cretaceous of Belgium, originally described by Von Meyer (1860), turns out to be assignable to the tylosaurine Hainosaurus cf. bernardi Dollo 1885. A small sediment sample, extracted from the bone, was analysed for coccoliths and revealed its early Late Campanian age. This is thus the earliest record of a tylosaurine mosasaur from Belgium.  相似文献   

微藻的应用概述   总被引：10，自引：0，他引：10  

梁英  麦康森 《海洋湖沼通报》1999,(2):70-82

微藻太阳能利用效率高、个体小、营养丰富、生长繁殖迅速、对环境的适应能力强、容易培养,因此受到人们的重视。微藻的培养开始于18世纪末,当时培养的种类是栅藻和小球藻等淡水藻类,目的是作为植物生理学的试验材料。到了第二次世界大战期间及战后时期,由于粮食缺乏,...  相似文献