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Microearthquake reveals the lithospheric structure at midocean ridges and oceanic transform faults
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作者 Zhiteng YU Jiabiao LI Weiwei DING 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2024年第3期697-700,共4页
Mid-ocean ridge and oceanic transforms are among the most prominent features on the seafloor surface and are crucial for understanding seafloor spreading and plate tectonic dynamics,but the deep structure of the ocean... Mid-ocean ridge and oceanic transforms are among the most prominent features on the seafloor surface and are crucial for understanding seafloor spreading and plate tectonic dynamics,but the deep structure of the oceanic lithosphere remains poorly understood.The large number of microearthquakes occurring along ridges and transforms provide valuable information for gaining an indepth view of the underlying detailed seismic structures,contributing to understanding geodynamic processes within the oceanic lithosphere.Previous studies have indicated that the maximum depth of microseismicity is controlled by the 600-℃isotherm.However,this perspective is being challenged due to increasing observations of deep earthquakes that far exceed this suggested isotherm along mid-ocean ridges and oceanic transform faults.Several mechanisms have been proposed to explain these deep events,and we suggest that local geodynamic processes(e.g.,magma supply,mylonite shear zone,longlived faults,hydrothermal vents,etc.)likely play a more important role than previously thought. 展开更多
关键词 microearthquake mid-ocean ridge oceanic transform fault oceanic lithosphere thermal structure earthquake location
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Discovery and characterization of a new hydrothermal field at 2°N on the slow-spreading Carlsberg Ridge
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作者 Zhongyan QIU Yejian WANG +6 位作者 Xiqiu HAN Honglin LI Xing YU Ruyong CUI Mou LI Xuegang CHEN Jiqiang LIU 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2024年第4期1106-1118,共13页
A new hydrothermal field(Tianshi)was discovered on the rift valley wall through plume anomaly surveys and geological work conducted in 2012 and 2018 between 2°35′N and 2°43′N of the slow-spreading Carlsber... A new hydrothermal field(Tianshi)was discovered on the rift valley wall through plume anomaly surveys and geological work conducted in 2012 and 2018 between 2°35′N and 2°43′N of the slow-spreading Carlsberg Ridge(CR).Here,the results of two expeditions conducted to detect and characterize the new hydrothermal field are reported.Mineralogical and geochemical data,as well as 14 C ages of a sediment core collected near the field are presented to reveal the hydrothermal history.Results show that the Tianshi field is a basalt-hosted hydrothermal system.Geochemical data of the sediments collected near the field indicate a strong hydrothermal contribution,and hydrothermal Fe and Cu fluxes range from 30 to 155 mg/(cm^(2)·ka)and 0.59 to 11.49 mg/(cm^(2)·ka),respectively.Temporal variations in the fluxes of hydrothermal Fe indicate that there have been at least three amplified hydrothermal venting events(H 1,H 2,and H 3)in the Tianshi field over the last 35.2 ka,in 28.6-35.2 ka BP,22.0-27.6 ka BP,and 1.2-11.4 ka BP,respectively.Hydrothermal event H 2 was driven by an increased magmatic production associated with sea level fall during the Last Glacial Maximum,while event H 3 was promoted by tectonic activity associated with a rapid sea level rise.This study further verified the role of sea level change in modulating hydrothermal activity on mid-ocean ridges. 展开更多
关键词 plume anomaly sediment core new hydrothermal field hydrothermal history Carlsberg ridge
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Characteristics of the Deep Crustal Structure of the Greenland–Iceland–Faroe Ridge in the North Atlantic
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作者 ZHANG Chunguan LI Fengyuan +3 位作者 ZHANG Qiang ZHANG Guoli HU Hongchuan YIN Rui 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2024年第S01期87-89,共3页
The Greenland–Iceland–Faroe Ridge,located between the central eastern part of Greenland and the northwestern edge of Europe,spans across the North Atlantic.As the core component of the Greenland–Iceland–Faroe Ridg... The Greenland–Iceland–Faroe Ridge,located between the central eastern part of Greenland and the northwestern edge of Europe,spans across the North Atlantic.As the core component of the Greenland–Iceland–Faroe Ridge,the Iceland is an alkaline basalt area,which belongs to the periodic submarine magmatism and submarine volcano eruption resulting from mantle plume upwelling(Jiang et al.,2020).For the oceanic plateaus,the characteristics of the Iceland are closest to the continental crust,so the Iceland is considered the most suitable for simulating the earliest continental crust on the Earth(Reimink et al.,2014). 展开更多
关键词 crustal thickness deep fault Moho surface gravity anomaly Greenland-Iceland-Faroe ridge
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Environmental characteristics of trace metals in seawater from the Ninety East Ridge in the Indian Ocean
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作者 Jingxi LI Di ZHANG +3 位作者 Fenghua JIANG Hong CHEN Wei CAO Chengjun SUN 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2024年第4期1119-1129,共11页
The Ninety East Ridge in the Indian Ocean has complex and unique characteristics.The concentrations and distribution characteristics of 10 trace metals(V,Cr,Mn,Fe,Co,Ni,Cu,Cd,Pb,and U)in seawater from the Ninety East ... The Ninety East Ridge in the Indian Ocean has complex and unique characteristics.The concentrations and distribution characteristics of 10 trace metals(V,Cr,Mn,Fe,Co,Ni,Cu,Cd,Pb,and U)in seawater from the Ninety East Ridge in the Indian Ocean were investigated.Results show that the average concentrations of different trace metals in all the collected seawater samples were 1.134μg/L for V,0.158μg/L for Cr,0.489μg/L for Mn,0.427μg/L for Fe,0.011μg/L for Co,0.395μg/L for Ni,0.403μg/L for Cu,0.097μg/L for Cd,0.139μg/L for Pb,and 3.470μg/L for U.Differences in the horizontal and vertical distributions of all measured trace metals were revealed,and the occurrence of high concentrations was nonuniform.In addition,the significant differences in the concentration distribution of different trace metals in seawater on both sides of the Ninety East Ridge present regional segmentation in the area for various trace metals in deep sea water.This study provided basic data for future investigations on the environmental and ecological impact of trace metals in the Indian Ocean and the potential water mass transport mechanism. 展开更多
关键词 trace metal environmental characteristic Ninety East ridge seawater Indian Ocean
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Cu-Zn isotope compositions of hydrothermal sediments from the southern Mid-Atlantic Ridge:implications to the sediment formation and mineral exploration
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作者 Baoju YANG Lianhua HE +3 位作者 Chuanshun LI Qiannan HU Bingfu JIN Jihua LIU 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2024年第5期1470-1485,共16页
Six hydrothermal sediment samples were collected from the Xunmei and Tongguan hydrothermal fields along the southern Mid-Atlantic Ridge during the China Ocean Cruise DY46 in 2017.Sulfides and oxides in the samples wer... Six hydrothermal sediment samples were collected from the Xunmei and Tongguan hydrothermal fields along the southern Mid-Atlantic Ridge during the China Ocean Cruise DY46 in 2017.Sulfides and oxides in the samples were separated,and Cu and Zn isotope compositions were analyzed.Results show that the ranges ofδ^(65)Cu values of the bulk sediments,sulfides,and oxides were 0.36‰-2.46‰,-0.21‰-1.10‰,and 0.68‰-1.52‰,respectively.Theδ^(65)Cu values of sulfides in four samples(46II-14,46II-30,46III-06,and 46II-09)were relatively low(-0.21‰-0.50‰),corresponding to theδ^(65)Cu values of sulfides from inactive old hydrothermal chimneys in northern Mid-Atlantic Ridge(n MAR),suggesting that the sulfides in the sediments were originated from collapsed dead chimney mainly.While theδ^(65)Cu values of the other two samples(46III-02 and 46III-08)were relatively high(1.10‰-0.96‰),corresponding to theδ^(65)Cu values for active hydrothermal chimneys sulfides in n MAR,which indicated that the sulfides in these two samples might mainly come from sulfide particles settled from active hydrothermal plume.Because of the high density of sulfide particles,they tended to settle near the hydrothermal vents first.Therefore,highδ^(65)Cu values of sulfides in 46III-02 and 46III-08 implied that undiscovered active hydrothermal vents near the sampling positions of 46III-02 in the Xunmei hydrothermal field and 46III-08 in the Tongguan hydrothermal field.Theδ^(66)Zn values of hydrothermal sediments and sulfides ranged 0.11‰-0.43‰and 0.29‰-0.67‰,respectively.In the four samples from the Xunmei hydrothermal field,a positive correlation was found between the distance of the sampling position from sulfide mineralized spot and the Zn isotopic ratio,showing that the greater the distance from the mineralized spot,the heavier the Zn isotope composition as seen in two samples(46II-30 and 46II-14)of the Xunmei-3 spot.This result aligned with the findings of Wilkinson et al.(2005)and Baumgartner et al.(2023),suggesting that the lower the Zn isotope composition,the closer it is to the hydrothermal vent.However,in the Xunmei hydrothermal field,the Zn isotope composition in the other two samples(46III-02and 46III-06)showed the opposite trend.This indicated that there might be an active hydrothermal vent near the sampling location of sample 46III-02.This observation aligned with the Cu isotope analysis results.This study showed that Cu-Zn isotopes are good indicators for understanding the formation mechanisms of hydrothermal sediments and for locating active hydrothermal vents. 展开更多
关键词 Cu-Zn isotope hydrothermal sediments mineral exploration southern Mid-Atlantic ridge
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Hydrographic Characteristics and Oceanic Heat Flux in the Upper Arctic Ocean over the Alpha Ridge Observed by the DTOP Platform in 2018 and 2021
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作者 WANG Yongjun LI Tao 《Journal of Ocean University of China》 CAS CSCD 2024年第2期304-316,共13页
In 2018 and 2021,the Drift-Towing Ocean Profilers(DTOP)provided extensive temperature and salinity data on the upper 120m ocean through their drifts over the Alpha Ridge north of the Canada Basin.The thickness and tem... In 2018 and 2021,the Drift-Towing Ocean Profilers(DTOP)provided extensive temperature and salinity data on the upper 120m ocean through their drifts over the Alpha Ridge north of the Canada Basin.The thickness and temperature maximum of Alaska Coastal Water(ACW)ranged from 20m to 40m and-1.5℃to-0.8℃,respectively,and the salinity generally maintained from 30.2 to 32.5.Comparison with World Ocean Atlas 2018’s climatology manifested a 40m-thick and warm ACW roughly ex-ceeding the temperature maximum by 0.4–0.5℃in June–August 2021.This anomalously warm ACW was highly related to the ex-pansion of the Beaufort Gyre in the negative Arctic Oscillation phase.During summer,the under-ice oceanic heat flux F_(w)^(OHF)was elevated,with a maximum value of above 25Wm^(-2).F_(w)^(OHF)was typically low in the freezing season,with an average value of 1.2Wm^(-2).The estimates of upward heat flux contributed by ACW to the sea ice bottom F_(w)^(OHF)were in the range of 3–4Wm^(-2)in June–August 2021,when ACW contained a heat content of more than 80MJm^(-2).The heat loss over this period was driven by a weak stratification upon the ACW layer associated with a surface mixed layer(SML)approaching the ACW core.After autumn,F_(w)^(OHF)was reduced(<2 Wm^(-2))except during rare events when it elevated F_(w)^(OHF)slightly.In addition,the intensive and widespread Ekman suction,which created a violent upwelling north of the Canada Basin,was largely responsible for the substantial cooling and thinning of the ACW layer in the summer of 2021. 展开更多
关键词 Arctic Ocean oceanic heat flux Alaska Coastal Water Alpha ridge
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Structural features in the mid-southern section of the Kyushu–Palau Ridge based on satellite altimetry gravity anomaly
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作者 Feifei Zhang Dingding Wang +3 位作者 Xiaolin Ji Fanghui Hou Yuan Yang Wanyin Wang 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2024年第4期50-60,共11页
The Kyushu–Palau Ridge(KPR),an anti-S-shaped submarine highland at the center of the Philippine Sea Plate(PSP),is considered the residual arc of the Izu–Bonin–Mariana Island Arc,which retains key information about ... The Kyushu–Palau Ridge(KPR),an anti-S-shaped submarine highland at the center of the Philippine Sea Plate(PSP),is considered the residual arc of the Izu–Bonin–Mariana Island Arc,which retains key information about the cessation of the Western Philippine Basin(WPB)expansion and the Parece Vela Basin(PVB)breakup.Herein,using the new generation of satellite altimetry gravity data,high-precision seafloor topography data,and newly acquired ship-borne gravity data,the topographic and gravity characteristics of the KPR mid-southern section and adjacent region are depicted.The distribution characteristics of the faults were delineated using the normalized vertical derivative–total horizontal derivative method(NVDR-THDR)and the minimum curvature potential field separation method.The Moho depth and crustal thickness were inverted using the rapid inversion method for a double-interface model with depth constraints.Based on these results,the crust structure features in the KPR mid-southern section,and the“triangular”structure geological significance where the KPR and Central Basin Rift(CBR)of the WPB intersect are interpreted.The KPR crustal thickness is approximately 6–16 km,with a distinct discontinuity that is slightly thicker than the normal oceanic crust.The KPR mid-southern section crust structure was divided into four segments(S1–S4)from north to south,formed by the CBR eastward extension joint action and clockwise rotation of the PVB expansion axis and the Mindanao fault zone blocking effect. 展开更多
关键词 structural features satellite altimetry gravity data Kyushu-Palau ridge Central Basin Rift FAULTS Moho depth
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Molybdenum isotope composition of the upper mantle and its origin:insight from mid-ocean ridge basalt
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作者 Shuo CHEN 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2024年第3期705-708,共4页
The molybdenum(Mo)isotope system is pivotal in reconstructing marine redox changes throughout Earth’s history and has emerged as a promising tracer for igneous and metamorphic processes.Understanding its composition ... The molybdenum(Mo)isotope system is pivotal in reconstructing marine redox changes throughout Earth’s history and has emerged as a promising tracer for igneous and metamorphic processes.Understanding its composition and variation across major geochemical reservoirs is essential for its application in investigating high-temperature processes.However,there is debate regarding theδ^(98/95)Mo value of the Earth’s mantle,with estimates ranging from sub-chondritic to super-chondritic values.Recent analyses of global mid-ocean ridge basalt(MORB)glasses revealed significantδ^(98/95)Mo variations attributed to mantle heterogeneity,proposing a two-component mixing model to explain the observed variation.Complementary studies confirmed the sub-chondriticδ^(98/95)Mo of the depleted upper mantle,suggesting remixing of subduction-modified oceanic crust as a plausible mechanism.These findings underscore the role of Mo isotopes as effective tracers for understanding dynamic processes associated with mantle-crustal recycling. 展开更多
关键词 molybdenum(Mo)isotope MANTLE crustal recycling mid-ocean ridge basalt(MORB)
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Nuclear charge radius predictions by kernel ridge regression with odd-even effects
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作者 Lu Tang Zhen-Hua Zhang 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第2期94-102,共9页
The extended kernel ridge regression(EKRR)method with odd-even effects was adopted to improve the description of the nuclear charge radius using five commonly used nuclear models.These are:(i)the isospin-dependent A^(... The extended kernel ridge regression(EKRR)method with odd-even effects was adopted to improve the description of the nuclear charge radius using five commonly used nuclear models.These are:(i)the isospin-dependent A^(1∕3) formula,(ii)relativistic continuum Hartree-Bogoliubov(RCHB)theory,(iii)Hartree-Fock-Bogoliubov(HFB)model HFB25,(iv)the Weizsacker-Skyrme(WS)model WS*,and(v)HFB25*model.In the last two models,the charge radii were calculated using a five-parameter formula with the nuclear shell corrections and deformations obtained from the WS and HFB25 models,respectively.For each model,the resultant root-mean-square deviation for the 1014 nuclei with proton number Z≥8 can be significantly reduced to 0.009-0.013 fm after considering the modification with the EKRR method.The best among them was the RCHB model,with a root-mean-square deviation of 0.0092 fm.The extrapolation abilities of the KRR and EKRR methods for the neutron-rich region were examined,and it was found that after considering the odd-even effects,the extrapolation power was improved compared with that of the original KRR method.The strong odd-even staggering of nuclear charge radii of Ca and Cu isotopes and the abrupt kinks across the neutron N=126 and 82 shell closures were also calculated and could be reproduced quite well by calculations using the EKRR method. 展开更多
关键词 Nuclear charge radius Machine learning Kernel ridge regression method
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Study on Relative Soil and Water Conservation Benefits of Ridge Tillage in Different Terrain Conditions in the Black Soil Area of Northeast China
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作者 赵玉明 姜洪涛 王世界 《Agricultural Science & Technology》 CAS 2015年第10期2354-2360,共7页
Ridge tillage, which is a very common and important tillage measure in the black soil area of northeast China, has some soil and water conservation bene- fits, but has little attention. It is very important to explore... Ridge tillage, which is a very common and important tillage measure in the black soil area of northeast China, has some soil and water conservation bene- fits, but has little attention. It is very important to explore the spatial distribution of the ridge direction of the arable land and its soil and water conservation benefits in different terrain conditions in the black soil area. So Binxian County of Heilongjiang Province was selected as the study area, and 168 field investigation units were ex- tracted by stratified sampling method and investigated. According to equations of slope gradient factor and slope gradient in ridge direction, and based on the soft- ware of Arcmap, SPSS and Excel, the investigation data of soil and water loss in Binxian County were analyzed and counted, The results show that in plain, hilly and mountainous areas, the average ground slope gradients are 1.92°, 6.20° and 8.27° respectively, and the average slope gradients along ridge direction are 1.33°, 4.52°and 6.45° respectively, which account for about 70%, 73% and 78% of the average ground slope gradients in the same terrain condition; the relative quantities of soil erosion in the present ridge tillage condition account for about 55%, 69% and 67% respectively of that in down-slope ridge tillage conditions, so the present ridge tillage has obviously relative soil and water conservation benefits. Based on these results, the reasons of the present ridge tillage status were analyzed, and some reform measures were proposed. The results could not only help to comprehend the spatial distribution and soil and water conservation benefits of ridge tillage in the black soil area of Northeast China, but also provide scientific references for the layout of local soil and water conservation measures. 展开更多
关键词 The black soil area in northeast China ridge tillage ridge direction Soil erosion Investigation of soil and water loss Soil and water conservation benefits
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Variations in melt supply along an orthogonal supersegment of the Southwest Indian Ridge(16°–25°E)
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作者 Caicai Zha Jian Lin +3 位作者 Zhiyuan Zhou Xubo Zhang Min Xu Fan Zhang 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2021年第5期94-104,共11页
The orthogonal supersegment of the ultraslow-spreading Southwest Indian Ridge at 16°–25°E is characterized by significant along-axis variations of mantle potential temperature.A detailed analysis of multibe... The orthogonal supersegment of the ultraslow-spreading Southwest Indian Ridge at 16°–25°E is characterized by significant along-axis variations of mantle potential temperature.A detailed analysis of multibeam bathymetry,gravity,and magnetic data were performed to investigate its variations in magma supply and crustal accretion process.The results revealed distinct across-axis variations of magma supply.Specifically,the regionally averaged crustal thickness reduced systematically from around 7 Ma to the present,indicating a regionally decreasing magma supply.The crustal structure is asymmetric in regional scale between the conjugate ridge flanks,with the faster-spreading southern flank showing thinner crust and greater degree of tectonic extension.Geodynamic models of mantle melting suggested that the observed variations in axial crustal thickness and major element geochemistry can be adequately explained by an eastward decrease in mantle potential temperature of about40℃ beneath the ridge axis.In this work,a synthesized model was proposed to explain the axial variations of magma supply and ridge segmentation stabilities.The existence of large ridge-axis offsets may play important roles in controlling melt supply.Several large ridge-axis offsets in the eastern section(21°–25°E)caused sustained along-axis focusing of magma supply at the centers of eastern ridge segments,enabling quasi-stable segmentation.In contrast,the western section(16°–21°E),which lacks large ridge-axis offsets,is associated with unstable segmentation patterns. 展开更多
关键词 ultraslow-spreading ridge Southwest Indian ridge ridge segmentation asymmetric accretion melt supply mantle temperature gradient
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Spreading-rate dependence of hydroacoustic and teleseismic seismicity of ridge-transform systems:East Pacific Rise,Galapagos Ridge,and Mid-Atlantic Ridge
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作者 Tingting Zheng Jian Lin Qiu Zhong 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2022年第5期124-135,共12页
Seismicity in ocean ridge-transform systems reveals fundamental processes of mid-ocean ridges,while comparisons of seismicity in different oceans remain rare due to a lack of detection of small events.From 1996 to 200... Seismicity in ocean ridge-transform systems reveals fundamental processes of mid-ocean ridges,while comparisons of seismicity in different oceans remain rare due to a lack of detection of small events.From 1996 to 2003,the Pacific Marine Environmental Laboratory of the National Oceanic and Atmospheric Administration(NOAA/PMEL)deployed several hydrophones in the eastern Pacific Ocean and the northern Atlantic Ocean.These hydrophones recorded earthquakes with small magnitudes,providing us with opportunities to study the seismic characteristics of ridge-transform systems at different spreading rates and make further comparisons of their differences.This study comparatively analyzed hydroacoustic and teleseismic data recorded on the fast-spreading East Pacific Rise(EPR,10°S to 12°N),intermediate-spreading Galapagos Ridge(103°W to 80°W),and slow-spreading Mid-Atlantic Ridge(MAR,15°N to 37°N).We present a systematic study of the spatial and temporal distribution of events,aftershock seismicity,and possible triggering mechanisms of aftershock sequences.Our analysis yields the following conclusions.(1)From the hydroacoustic data,the EPR transform faults had the highest average seismicity rate among the three regions.(2)Along-ridge event distributions show that a high number of earthquakes were concentrated on the EPR,while they became dispersed on the GR and fewer and more scattered on the MAR,reflecting that the different tectonic origins were closely correlated with the spreading rate.(3)Analysis from mainshock-aftershock sequences shows no significant differences in the aftershock decay rate among the three regions.(4)Multiple types of aftershock triggering models were inferred from Coulomb stress changes:strike-slip mainshocks triggered strike-slip aftershocks and normal faulting aftershocks,and normal faulting mainshocks triggered normal faulting aftershocks.Although these results are case studies,they may be applicable to other ocean ridge-transform systems in future investigations.Our results provide important new insights into the seismicity of global ocean ridge-transform systems. 展开更多
关键词 East Pacific Rise Galapagos ridge Mid-Atlantic ridge hydroacoustic and teleseismic seismicity ridge-transform system
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A study of impact of the reclamation and artificial island projects on tidal currents and sediment concentration in radial sand ridge field of the South Yellow Sea 被引量:3
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作者 赵强 何琴燕 +1 位作者 杨耀芳 黄秀清 《Marine Science Bulletin》 CAS 2015年第1期71-85,共15页
The two-dimensional hydrodynamic model, MIKE21, is applied to simulate the tidal currents and sediment concentration in the radial sand ridges of the South Yellow Sea. Results are in accordance with in situ observatio... The two-dimensional hydrodynamic model, MIKE21, is applied to simulate the tidal currents and sediment concentration in the radial sand ridges of the South Yellow Sea. Results are in accordance with in situ observations. Then the variations of tidal currents and suspended sediment concentration caused by reclamation and artificial islands projects are simulated. The results show that the impacts are limited around the project areas. After the projects, the fan-shaped, Jianggang centered tidal current pattern would be replaced by a pattern which is formed by two tidal paths. One locates at the Xiyang channel in north-south direction, and the other locates at the Huangshayang channel in east-west direction. The reclamation of Tiaozini separates the waters into south portion and north portion. The changes of sediment concentrations coincide with those of currents. Both the sediment concentrations and tidal currents increase at the northwest of Dongsha and the south of Gaoni, while both decrease at the north and south of Tiaozini, and the east and southwest of Dongsha. 展开更多
关键词 radial sand ridges RECLAMATION artificial island tidal currents suspended sediment concentration numerical modeling
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Ridge Waveguide Electro-Optic Polymer Modulator with a New Kind of Corona Poled Crosslinkable Polyurethane 被引量:1
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作者 杨晓红 杜云 +2 位作者 殷爱民 石志文 吴荣汉 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2001年第2期130-133,共4页
A polymer electro optic modulator has been fabricated with the functional layer acting as a kind of corona poled crosslinkable polyurethane. The three optical layers, namely waveguide, photolithography and oxygen are... A polymer electro optic modulator has been fabricated with the functional layer acting as a kind of corona poled crosslinkable polyurethane. The three optical layers, namely waveguide, photolithography and oxygen are fabricated by spin coating. With the Reactive Ion Etching method, the ridge of the waveguide is constructed. With light at 1 31μm being fiber coupled to waveguide, the mode and the modulation properties of these devices are demonstrated in a micron control system. 展开更多
关键词 MODULATOR polymer ridge waveguide
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一种基于核ridge回归的解耦控制系统 被引量:2
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作者 全勇 杨杰 《上海交通大学学报》 EI CAS CSCD 北大核心 2003年第9期1421-1425,共5页
提出了一种新的基于核ridge回归的解耦方法.该方法具有传统径向基(RBF)神经网络解耦方法对被控对象数学模型依赖性小的特点,同时又能有效地克服RBF神经网络解耦方法对训练样本要求高、噪声敏感和解耦速度慢的缺点,经核ridge解耦器补偿... 提出了一种新的基于核ridge回归的解耦方法.该方法具有传统径向基(RBF)神经网络解耦方法对被控对象数学模型依赖性小的特点,同时又能有效地克服RBF神经网络解耦方法对训练样本要求高、噪声敏感和解耦速度慢的缺点,经核ridge解耦器补偿后的控制系统具有被调节量和调节量之间耦合作用小、动态特性好、稳定性强的优点.补偿后的控制系统具有很强的校正能力,对外界各种干扰也有较强的解耦效果和控制质量.仿真试验表明,采用核ridge解耦器的多变量控制系统能够有效地解除系统各变量之间的耦合作用,且结构简单、易于实现,大大增强了解耦控制系统的实用性能. 展开更多
关键词 解耦 多变量控制系统 ridge回归
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Seismic phases from the Moho and its implication on the ultraslow spreading ridge 被引量:5
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作者 ZHANG Jiazheng ZHAO Minghui +2 位作者 QIU Xuelin LI Jiabiao RUAN Aiguo 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2013年第12期75-86,共12页
The Moho interface provides critical evidence for crustal thickness and the mode of oceanic crust accretion. The seismic Moho interface has not been identified yet at the magma-rich segments (46°-52°E) of ... The Moho interface provides critical evidence for crustal thickness and the mode of oceanic crust accretion. The seismic Moho interface has not been identified yet at the magma-rich segments (46°-52°E) of the ultra- slow spreading Southwestern Indian Ridge (SWIR). This paper firstly deduces the characteristics and do- mains of seismic phases based on a theoretical oceanic crust model. Then, topographic correction is carried out for the OBS record sections along Profile Y3Y4 using the latest OBS data acquired from the detailed 3D seismic survey at the SWIR in 2010. Seismic phases are identified and analyzed, especially for the reflected and refracted seismic phases from the Moho. A 2D crustal model is finally established using the ray tracing and travel-time simulation method. The presence of reflected seismic phases at Segment 28 shows that the crustal rocks have been separated from the mantle by cooling and the Moho interface has already formed at zero age. The 2D seismic velocity structure across the axis of Segment 28 indicates that detachment faults play a key role during the processes of asymmetric oceanic crust accretion. 展开更多
关键词 Moho interface seismic phases ultra-slow spreading ridge 2D crustal structure SouthwesternIndian ridge (SWIR)
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New discovery of seafloor hydrothermal activity on the Indian Ocean Carlsberg Ridge and Southern North Atlantic Ridge-progress during the 26th Chinese COMRA cruise 被引量:5
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作者 TAO Chunhui WU Guanghai +3 位作者 DENG Xianming QIU Zhongyan HAN Chenhua LONG Yanmei 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2013年第8期85-88,共4页
The 26th Chinese COMRA (China Ocean Mineral Resources Research & Development Association) cruise was an important cruise. The Carlsberg Ridge (CR) of the Northwest Indian Ocean and the North Atlantic Ridge (NAR... The 26th Chinese COMRA (China Ocean Mineral Resources Research & Development Association) cruise was an important cruise. The Carlsberg Ridge (CR) of the Northwest Indian Ocean and the North Atlantic Ridge (NAR), in which less investigation has been carried out for hydrothermal activities, were investigated and studied during the first two legs of the 26th COMRA cruise. During the first leg, we found one hydrother- mal activity field located in the CR at 3.5^-3.8~ N on the Northwest Indian Ocean Ridge (NWIR), and sampled seafloor polymetallic sulfide deposits where only abnormalities were found before. During the second leg, we found a new hydrothermal anomaly field located in the NAR at 4^-7~N. The discovery of two hydrother- real and anomaly fields filled in the gap of hydrothermal investigation and study in the corresponding re- ~ions for China. 展开更多
关键词 26th COMRA cruise Carlsberg ridge Indian Ocean North Atlantic ridge seafloor hydrothermal activity
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Geological structures of ridges with relation to the definition of three types of seafloor highs stipulated in Article 76 被引量:3
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作者 WANG Weiguo 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2011年第5期125-140,共16页
The ridge like seafloor highs with various geological origins can be classed into mid-ocean ridges,transverse ridges related to transform faults,hot spot/mantle plume originated ridges,microcontinent rifted from major... The ridge like seafloor highs with various geological origins can be classed into mid-ocean ridges,transverse ridges related to transform faults,hot spot/mantle plume originated ridges,microcontinent rifted from major continent,intra-plate arc formed by interaction of two oceanic plates,and tectonic ridges uplifted by later tectonic activity.Those ridges moved towards the convergent continental margins along with the underlain plate drifting and formed so-called accreted ridges commonly trending at a high angle to the continental margins.At divergent continental margins,the continental crusts were extended and thinned accompanying with magmatism,which formed high terrains protruding or parallel to the coastal line.The ridges worldwide have various origins and the crustal thicknesses and structures of them are diversity.The crusts beneath the microcontinents,and the transverse ridges along the transform margin,and the seafloor highs beside the passive continental margins are continental,while the crusts of other ridges are oceanic.Article 76 of the United Nations Convention on the Law of the Sea (UNCLOS) has classed the seafloor highs worldwide into three legal categories,namely oceanic ridges,submarine ridges and submarine elevations,for the purpose to delineate the outer limit of the coastal States' continental shelf beyond 200 nautical miles.To define the categories of the legal seafloor highs to which the ridges with various geological origins belong,the continuities in morphology and geology including the rock types,crustal structures,origins and tectonic setting of the ridges and the coastal States' land mass with its submerged prolongation should be taken into account.If a ridge is continuous both in morphology and geology with the coastal States' land mass and its submerged prolongation,it is a submarine elevation stipulated in Article 76.If it is discontinuous in morphology,the ridge should be regarded as oceanic ridges.If a ridge is continuous in morphology but discontinuous in geology with the coastal States' land mass and its submerged prolongation,then it is a submarine ridge as stipulated in Article 76. 展开更多
关键词 ridge geological structure UNCLOS continental shelf ridge provisions
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TEM investigations of South Atlantic Ridge 13.2°S hydrothermal area 被引量:3
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作者 TAO Chunhui XIONG Wei +2 位作者 XI Zhenzhu DENG Xianming XU Yixian 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2013年第12期68-74,共7页
According to the exploration contract about polymetallic sulfides in the SWIR (Southwest Indian Ridge) signed by China with the International Seabed Authority, to delineate sulfide minerals and estimate resource qua... According to the exploration contract about polymetallic sulfides in the SWIR (Southwest Indian Ridge) signed by China with the International Seabed Authority, to delineate sulfide minerals and estimate resource quantity are urgent tasks. We independently developed our first coincident loop Transient Electromagnetic Method (TEM) device in 2010, and gained the TEM data for seafloor sulfide at South Atlantic Ridge 13.2°S in June 2011. In contrast with the widely applied CSEM (Marine controlled-source electromagnetic) method, whose goal is to explore hydrocarbons (oil/gas) of higher resistivity than seawater from 102 to 103 m below the sea floor, the TEM is for low resistivity minerals, and the target depth is from 0 to 100 m below the sea floor. Based on the development of complex sulfide geoelectrial models, this paper analyzed the TEM data obtained, proposing a new method for seafloor sulfide detection. We present the preliminary trial results, in the form of apparent resistivity sections for both half-space and full-space conditions. The results cor- respond well with the observations of the actual hydrothermal vent area, and the detection depth reached 50-100m below the bed, which verified the capability of the equipment. 展开更多
关键词 transient electromagnetic method mid-ocean ridge hydrothermal activity seafloor polymetallicsulfides South Atlantic ridge
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Vibro-acoustic Radiation Characteristics Analysis of Railway Vehicle Wheel with Damping Ridges Based on Modal Strain Energy 被引量:2
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作者 HE Bin XIAO Xinbiao +1 位作者 JIN Xuesong FANG Jianying 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2011年第6期1056-1067,共12页
The existing researches on the damping wheel mainly focus on investigating the influence of damping structure change on the vibro-acoustic control.The changes include the geometric size of the damping structure,the da... The existing researches on the damping wheel mainly focus on investigating the influence of damping structure change on the vibro-acoustic control.The changes include the geometric size of the damping structure,the damping material parameters,and the placement,and so on.In order to further understand the mechanism in reducing the acoustic radiation of railway wheel with layer damping treatment,in this paper,the wheel is simply modified by a full-sized circular plate.The circle plate side has stuck circumference constrained damping ridges and radial constrained damping ridges on it.Based on a hybrid finite element method-boundary element method(FEM-BEM),the paper develops a vibro-acoustic radiation model for such a distributed constrained damping structure.The vibration and acoustic radiation of the circular plate is analyzed.In the analysis,the dynamic response of the system is obtained by using the 3D finite model superposition method.The obtained vibration response is used as the initial boundary condition in solving Helmholtz boundary integral equation for the sound radiation analysis.In the procedure,firstly,the modal analysis of the circular plate is performed to get the distribution of the system modal strain energy.Secondly,the vibro-acoustic radiation characteristics of the plate with different kinds of circumference damping ridges and radial damping ridges are compared in order to try to find the best effective damping ridge structure.Thirdly,using the distribution of the plate modal strain energy investigates the effect of the ridge distribution locations on the circular plate on its vibro-acoustic radiation.The calculation and analysis research results show that,the sticking circumference and radial damping ridges on the plate can control the vibro-acoustic radiation of the plate effectively in different frequency range.The distribution of the constrained damping ridge has an effect on reduction in vibro-acoustic radiation of the circular plate.The present research is very useful in the design of railway wheel with low noise level. 展开更多
关键词 wheel/rail noise vibro-acoustic radiation circumference damping ridge radial damping ridge modal strain energy
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