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Characteristics of transfer zones under the influence of preexisting faults and regional stress transformation:Wenchang A subsag,Zhujiang River Mouth Basin,northern South China Sea
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作者 Wei LI Mingyue CAO +7 位作者 Meifang MENG Caiwei FAN Hui LI Jia LI Wanqiu WU Ruiqing QIN Xingan LI Yiming LIU 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2024年第3期744-759,共16页
A transfer zone in rift basins preserves important information on regional tectonic evolution and plays significant roles in hydrocarbon accumulation.Based on the systematic analysis of 3D seismic data and hydrocarbon... A transfer zone in rift basins preserves important information on regional tectonic evolution and plays significant roles in hydrocarbon accumulation.Based on the systematic analysis of 3D seismic data and hydrocarbon accumulation conditions,the geometry,kinematics,and reservoir control of a large synthetic overlapping transfer zone in the south of the Wenchang A subsag in the Zhujiang(Pearl)River Mouth basin were investigated.Results indicate that the development and evolution of the transfer zone was controlled by the interaction between pre-existing faults and regional stress transformation.The intense rifting of the main faults of the transfer zone controlled the development of source rocks and faultcontrolled slope break paleogeomorphology.The strike-slip overprint since the Oligocene is conducive to the formation of a large-scale fault-anticline trap,and the secondary faults in the transfer zone contribute to the hydrocarbon transportation.The conjugate intersection area of the NE-and NW-trending faults offers more opportunity for hydrocarbon migration and accumulation. 展开更多
关键词 transfer zone pre-existing fault regional stress transformation CENOZOIC Wenchang A Subsag Zhujiang(Pearl)River Mouth Basin
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On Radiation Boundary Conditions and Wave Transformation Across the Surf Zone 被引量:2
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作者 许泰文 温志中 《China Ocean Engineering》 SCIE EI 2001年第3期395-406,共12页
The purpose of this paper is to extend the validity of Li's parabolic model (1994) by incorporating a combined energy factor in the mild-slope equation and by improving the traditional radiation boundary condition... The purpose of this paper is to extend the validity of Li's parabolic model (1994) by incorporating a combined energy factor in the mild-slope equation and by improving the traditional radiation boundary conditions. With wave breaking and energy dissipation expressed in a direct form in the equation, the proposed model could provide an efficient numerical scheme and accurate predictions of wave transformation across the surf zone. The radiation boundary conditions are iterated in the model without use of approximations. The numerical predictions for wave height distributions across the surf zone are compared with experimental data over typical beach profiles. In addition, tests of waves scattering around a circular pile show that the proposed model could also provide reasonable improvement on the radiation boundary conditions for large incident angles of waves. 展开更多
关键词 radiation boundary condition wave transformation mild-slope equation surf zone
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Understanding ductile-to-brittle transition of metallic glasses from shear transformation zone dilatation 被引量:4
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作者 M.Q.Jiang G.Wilde +1 位作者 F.Jiang L.H.Dai 《Theoretical & Applied Mechanics Letters》 CAS CSCD 2015年第5期200-204,共5页
A theoretical model that takes into account the flee-volume aided cooperative shearing of shear transformation zones (STZs) is developed to quantitatively understand the ductile-to-brittle transition (DBT) of meta... A theoretical model that takes into account the flee-volume aided cooperative shearing of shear transformation zones (STZs) is developed to quantitatively understand the ductile-to-brittle transition (DBT) of metallic glasses. The STZ dilatational strain is defined as the ratio of STZ-activated free volume to STZ volume itself. The model demonstrates that the STZ dilatational strain will increase drastically and exceed the characteristic shear strain of STZ as temperature decreases below a critical value. This critical temperature is in good agreement with the experimentally measured DBT temperature. Our results suggest that the DBT of metallic glasses is underpinned by the transition of atomic-cluster motions from STZ-tvpe rearrangements to dilatational processes (termed tension transformation zones (TrZs)). 展开更多
关键词 Ductile-to-brittle transitionMetallic glassFractureShear transformation zoneTension transformation zone
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MICROSTRUCTURE TRANSFORMATION IN THE WELDING HEAT AFFECTED ZONE OF 800MPa GRADE ULTRA FINE STRUCTURED STEEL 被引量:1
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作者 J.B. Liu L.J. Hu +3 位作者 Y.T.Wang Z. Q. Liu K. Miao Z.L. Tian 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2004年第3期238-246,共9页
The transformation behavior and microstructure development in the heat affected zone(HAZ)of 800MPa grade ultra fine structured steel was investigated.It was found that the HAZ has intermediate temperature transformati... The transformation behavior and microstructure development in the heat affected zone(HAZ)of 800MPa grade ultra fine structured steel was investigated.It was found that the HAZ has intermediate temperature transformation characteristics in a wide range of cooling rates,with the bainite sheaves consisting of bainite ferrite plates without carbide precipitation and retained austenite in the fast cooling regime.At relatively high cooling rates,which corresponded to low heat inputs,the hardness of the simulated HAZ was above that of the base metal.When the cooling rate was below 9C/s,the welding HAZ would have an obvious softening.The analysis of transformation rates in continuous cooling processes was completed by numerical differential method.The result indicated that the microstructure transformation rate of the HAZ in 800MPa grade ultra fine structured steel changed sharply to slow speeds when the cooling time t8/5 is longer than 7s. 展开更多
关键词 ultra fine structured steel WELD heat affected zone transformation rate microstructure
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A review of POPs in the fragile critical zone of the Tibetan Plateau: transport and transformation 被引量:1
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作者 Jun Li Guoli Yuan 《Acta Geochimica》 EI CAS CSCD 2017年第3期396-399,共4页
The near-surface environment of the Tibetan Plateau is a fragile critical zone. Our understanding of the transport and transformation of persistent organic pollutants(POPs) in the ecosystem has significantly improved ... The near-surface environment of the Tibetan Plateau is a fragile critical zone. Our understanding of the transport and transformation of persistent organic pollutants(POPs) in the ecosystem has significantly improved with research conducted in recent decades. In the current study,POP concentrations in soils logarithmically decreased and fractionated with increasing distance from the source area,patterns attributed to air–soil exchange. Transport from soils resulted in the enrichment of POP concentrations in plants and sediments. The enantiomeric fraction indicated that transformation of POPs in soils was significantly correlated with altitude. At the same time, the chiral signature of POPs in soils was maintained from soils to sediments, while the chiral transformation from soils to plants was found to be complex. 展开更多
关键词 Tibetan Plateau Critical zone TRANSPORT transformation POPS
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Study on Migration and Transformation Rule of Organic Pollutants (COD) in Aerated Zone
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作者 GaoTaizhong HuangQunxian +3 位作者 LiuYe QiPeng ZhangHuanzhen CaiHesheng 《Journal of China University of Geosciences》 SCIE CSCD 2003年第1期73-78,共6页
Collecting waste water with a certain c onc entration of organic pollutants COD (chemical oxygen demand), static adsorption, static biodegradation and dynamic soil column experiments were made in laborato ry, we rese... Collecting waste water with a certain c onc entration of organic pollutants COD (chemical oxygen demand), static adsorption, static biodegradation and dynamic soil column experiments were made in laborato ry, we researched migration and transformation of COD in aerated zone, and put f orward a mathematical model showing the process. The results show that adsorptio n of organism in aerated zone is linear, which is represented by Henry's law s =K dc+s d, adsorption coefficient K d=0.069 3; biodegradati on diagram accord basically with first order kinetics equation c=c 0e -K 1t , biodegradation coefficient K 1 = 0.049 9 d -1 ; dispersio n coefficient D= 0.002 42 m 2/d in experiments. The migration and transform ation of organic pollutants (COD) in aerated zone jointly result from many f actors such as dispersion, adsorption and biodegradation etc.. 展开更多
关键词 chemical oxygen demand of organic pollutants aerated zone migration and transformation.
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Unstable Rifts,a Leaky Transform Zone and a Microplate:Analogues from South Iceland 被引量:1
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作者 Maryam Khodayar Sveinbjorn Bjornsson +1 位作者 Skúli Víkingsson Guorún Sigríour Jonsdottir 《Open Journal of Geology》 2020年第4期317-367,共51页
A structural analysis was undertaken in the South Iceland Seismic Zone (SISZ) transform zone, and in the Hreppar Microplate (HMP) located between the propagating Eastern Rift Zone (ERZ) and the receding Western Rift Z... A structural analysis was undertaken in the South Iceland Seismic Zone (SISZ) transform zone, and in the Hreppar Microplate (HMP) located between the propagating Eastern Rift Zone (ERZ) and the receding Western Rift Zone (WRZ). The age of the oceanic crust in these areas is 3.4 Ma to present. About 20,000 fracture segments on aerial images reflect the dominance of NNE extensional structures in the WRZ. Around 9,000 basement faults, intrusions, secondary fractures, surface ruptures of earthquakes, and leakages were mapped in the outcrops of the HMP and the SISZ. About 23% of these fractures strike NNE, while 77% are dominantly northerly dextral and ENE sinistral, and secondarily E-W, WNW and NW sinistral strike- and oblique-slip structures, forming a Riedel shear pattern typical of a transform zone. Dyke injections into Riedel shears indicate a leaky transform zone. Fractures reactivated, accumulated slip, and re-opened for fluid flow. The ENE faults dip mostly to the southeast and could be the present boundary of the SISZ to the north. A 10 - 30 km wide ENE structural zone hosts a valley to the east, which could be deeper in the west. This ENE zone contains all the earthquakes, dominant ENE rivers, frequent ENE secondary fractures, and is likely the active part of the SISZ. The HMP does not show rotation since 3.4 Ma despite being between two rift segments. Future propagation/recession of the rift segments along their N55&deg;E sections would cause a migration and a clockwise rotation of the SISZ from ENE to E-W. The boundary faults of the SISZ would then be E-W, with unchanged internal Riedel shears, compensating its sinistral motion. Insights into complexities of diverging plate boundaries are critical for resource management in such tectonic contexts. 展开更多
关键词 Unstable Diverging Plate Boundaries South Iceland Seismic zone Leaky transform zone Rotation of Microplate Tectonics of Iceland
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Structures and Styles of Deformation in Rift,Ridge,Transform Zone,Oblique Rift and a Microplate Offshore/Onshore North Iceland 被引量:1
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作者 Maryam Khodayar Sveinbjorn Bjornsson 《International Journal of Geosciences》 2018年第8期461-511,共51页
The diverging plate boundaries in North Iceland and its shelf display a complex tectonic at the Kolbeinsey Ridge (K-R), the Northern Rift Zone (NRZ), and the Tj?rnes Fracture Zone containing the Grímsey Oblique R... The diverging plate boundaries in North Iceland and its shelf display a complex tectonic at the Kolbeinsey Ridge (K-R), the Northern Rift Zone (NRZ), and the Tj?rnes Fracture Zone containing the Grímsey Oblique Rift (GOR), the Húsavík-Flatey Fault (HFF), and the Dalvík Lineament (DL). While active deformation is well-known, the structural pattern is sporadically mapped and a comprehensive account of the upper Tertiary-present deformation is not fully at hand. To address the gaps, this paper provides new regional tectonic maps with continuous coverage, and detailed analyses of the deformation. Faults, open fractures, prominent joints and volcanic edifices were identified on Multibeam/Single beam, Spot 5, and Digital Elevation Model, and subjected to multidisciplinary structural analysis and correlation with selected data. Some of the results are: 1) Six sets constitute the structural pattern. The N-S rift-parallel normal faults are 1/3, and the shear fractures of the transform zone and the oblique rift 2/3 of the fracture population. The en échelon arrangements above deep-seated shear zones indicate dextral slip on WNW to NW, and sinistral slip on NNE to ENE faults, conformable with earthquake data. 2) During the polyphase tectonic, the six sets led to basin and horst formation, block compartmentalisation, rotation, horsetail splay, rhomb-graben in relay zone of strike-slips, and volcanism. 3) Listric faults are absent and the steeply-dipping faults are antithetic, synthetic, or form extensional flower structures above 4 km depth. The Plio-pleistocene/present syn-sedimentary deformation caused a deep half graben in the Eyjafjarearáll Basin (Ey), fault growth, rollover, and sediment onlaps, with some of the faults still active. 4) The plate boundaries of K-R/Ey, GOR/?xarfjreur/NRZ, and DL delimit a major microplate labelled here as Grímsey-Tj?rnes-Dalvík. 5) The WNW earthquake cluster in GOR corresponds either to a blind horsetail splay fault or to initiation of a transform segment parallel to the HFF. The described tectonic-sedimentary-magmatic deformation is relevant to other diverging plate boundaries where similar sets control the hydrocarbon and geothermal resources. 展开更多
关键词 Kolbeinsey Ridge Iceland Northern Rift zone Tjornes transform zone Grimsey Oblique Rift Grimsey-Tjornes-Dalvík Microplate Magmatic/Sedimentary/Tectonic Processes
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Influence of hexagonal to orthorhombic phase transformation on diffusion-controlled dendrite evolution in directionally solidified Sn−Ni peritectic alloy
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作者 Peng PENG Bi-zhou ZHAO +4 位作者 Jia-tai WANG Xing PEI Zi-jie LIU Lu GAN Sheng-yuan LI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第5期1728-1740,共13页
The hexagonal to orthorhombic(HO)transformation fromβ-Ni_(3)Sn_(2)(hexagonal)phase toα'-Ni_(3)Sn_(2)(orthorhombic)phase was confirmed in directionally solidified Sn−Ni peritectic alloys.It is shown that the reme... The hexagonal to orthorhombic(HO)transformation fromβ-Ni_(3)Sn_(2)(hexagonal)phase toα'-Ni_(3)Sn_(2)(orthorhombic)phase was confirmed in directionally solidified Sn−Ni peritectic alloys.It is shown that the remelting/resolidification process which is caused by both the temperature gradient zone melting(TGZM)and Gibbs−Thomson(G−T)effects can take place on secondary dendrites.Besides,the intersection angle between the primary dendrite stem and secondary branch(θ)is found to increase fromπ/3 toπ/2 as the solidification proceeds.This is the morphological feature of the HO transformation,which can change the diffusion distance of the remelting/resolidification process.Thus,a diffusion-based analytical model is established to describe this process through the specific surface area(S_(V))of dendrites.The theoretical prediction demonstrates that the remelting/resolidification process is restricted when the HO transformation occurs during peritectic solidification.In addition,the slope of the prediction curves is changed,indicating the variation of the local remelting/resolidification rates. 展开更多
关键词 directional solidification dendritic solidification peritectic microstructures Gibbs−Thomson effect temperature gradient zone melting HO transformation
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融合Transformer和LSTM的蓝莓根区土壤含水量预测模型
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作者 王亿 曹姗姗 +3 位作者 孙伟 胡博 古丽米拉·克孜尔别克 孔繁涛 《湖北农业科学》 2024年第8期78-84,共7页
针对土壤含水量预测模型存在难以解决非线性复杂特征、易陷入局部极小值等问题,构建融合Transformer和LSTM的土壤含水量深度学习预测模型(Transformer-LSTM)。采集山东省青岛市黄岛区丁家寨村蓝莓(Vaccinium spp.)生产区冷棚与露天2个... 针对土壤含水量预测模型存在难以解决非线性复杂特征、易陷入局部极小值等问题,构建融合Transformer和LSTM的土壤含水量深度学习预测模型(Transformer-LSTM)。采集山东省青岛市黄岛区丁家寨村蓝莓(Vaccinium spp.)生产区冷棚与露天2个站点的蓝莓根区土壤和气象数据作为建模数据,根据皮尔逊相关性和偏自相关性分析选择模型的数据输入特征与输入长度,与单一的Transformer模型和LSTM模型进行对比分析,评估模型对土壤含水量的预测性能。结果表明,Transformer-LSTM模型在预测精度上均优于单一的Transformer模型和LSTM模型,Transformer-LSTM模型的平均绝对误差(MAE)、均方根误差(RMSE)、平均绝对百分比误差(MAPE)、决定系数(R^(2))分别为0.245 9、0.572 0、0.012 1、0.960 6。Transformer-LSTM模型可以更全面地提取蓝莓种植环境因子输入序列中的特征信息,有效提升土壤含水量因子预测精度和水平。 展开更多
关键词 蓝莓(Vaccinium spp.) 根区土壤 含水量 transformER LSTM 预测模型
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Tectonic Control of the Theistareykir Geothermal Field by Rift and Transform Zones in North Iceland:A Multidisciplinary Approach
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作者 Maryam Khodayar Sveinbjorn Bjornsson +3 位作者 Sigurour Garoar Kristinsson Ragna Karlsdóttir Magnús Olafsson Skúli Víkingsson 《Open Journal of Geology》 2018年第6期543-584,共42页
This paper presents a multidisciplinary structural analysis of a 165 km2 area in the Northern Rift Zone and the Tj&#246;rnes Fracture Zone of Iceland, and unravels the tectonic control of the Theistareykir geother... This paper presents a multidisciplinary structural analysis of a 165 km2 area in the Northern Rift Zone and the Tj&#246;rnes Fracture Zone of Iceland, and unravels the tectonic control of the Theistareykir geothermal field and its surroundings. About 10729 fracture segments (faults, open fractures, joints) are identified in the upper Tertiary to Holocene igneous series. The segments were extracted from aerial images and hillshade, and then analyzed in terms of number of sets, geometry, motions, frequency, and relative age. The correlation with surface geothermal manifestations, resistivity, earthquakes, and occasional well data reveals the critical regional and local fractures at the surface, reservoir level and greater depth. The main conclusions of this study are: 1) The structural pattern consists of N-S rift-parallel extensional fractures and the Riedel shears of the transform zone striking NNE, ENE, E-W, WNW and NW, which compartmentalize together the blocks at any scale. 2) The en échelon segmentation shows strike and oblique slips on the Riedel shears, with a dextral component on the WNW and NW planes and a sinistral component on the NNE to ENE faults. 3) Fractures form under the influence of the transform mechanism and the effect of rifting becomes significant only with time. 4) The WNW dextral oblique-slip Stórihver Fault of the transform zone has a horsetail splay that extends eastwards into the geothermal field. There, this structure, along with few NW, ENE, NNE and N-S fractures, controls the alteration, alignment of fumaroles, emanating deep gases. These fractures also rupture during natural or induced earthquakes. 5) The resistivity anomalies present en échelon geometries controlled by the six fracture sets. These anomalies display clockwise and anticlockwise rotations within the upper 8 km crustal depth, but at 8 km depth, only three sets (the N-S rift structures, and the E-W and the NW Riedel shears) are present at the rift and transform plate boundaries. Results of this study are relevant to resource exploration in other complex extensional contexts where rift and transform interact.&#246;&#246;&#246; 展开更多
关键词 Northern Rift zone of Iceland Tjornes transform zone Tectonic Control of Geothermal Activity Fractured Reservoir EARTHQUAKES Resistivity Anomalies
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智慧教育示范区何以实现整体教育数字化转型:问题审思、策略设计与实施路径
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作者 王星 李怀龙 《成都师范学院学报》 2025年第1期98-106,共9页
智慧教育示范区是教育数字化转型的先行示范窗口,但在发展中依然面临新基建革新受限、共建资源配置失衡、教学改革重量轻质、数据治理范式尚未成型等问题。基于这些问题,提出了党建引领、标准规约、示范先行和培引结合等智慧教育示范区... 智慧教育示范区是教育数字化转型的先行示范窗口,但在发展中依然面临新基建革新受限、共建资源配置失衡、教学改革重量轻质、数据治理范式尚未成型等问题。基于这些问题,提出了党建引领、标准规约、示范先行和培引结合等智慧教育示范区教育数字化转型策略,探索出智慧教育示范区教育数字化转型的实施路径:一是在融合发展上,促进智慧教育示范区建设与智慧城区发展双向协同;二是在工程导向上,统筹数字化转型实践体系实现系统化发展;三是在智能教育资源服务上,系统整合资源以深度融入教育教学改革;四是在重点突破上,聚力创新解决教育改革中的关键痛点难点。有鉴于此,未来需要深入探索智慧教育示范区实现整体数字化转型的系统运行机制,形成区域教育数字化转型发展可供推广的实践范式。 展开更多
关键词 智慧教育 智慧教育示范区 教育数字化 数字化转型 教育改革 数字治理
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Microstructure evolution and phase transformation of the mushy zone in a quenchedβ-solidifying TiAl alloy
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作者 Fuqiang Zhang Xianfei Ding +5 位作者 Leming Xu Xin Feng Hai Nan Jianping He Yongfeng Liang Junpin Lin 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2024年第2期28-41,共14页
This study investigates the phase constitutions and transformations that occur in the mushy zone and in the adjacent phase fields of a directionally solidified Ti-44Al-8Nb-1Cr alloy via quenching technique.The results... This study investigates the phase constitutions and transformations that occur in the mushy zone and in the adjacent phase fields of a directionally solidified Ti-44Al-8Nb-1Cr alloy via quenching technique.The results indicate that the mushy zone consists of unmeltedβdendrites and interdendritic liquid,whose formation can be attributed to the difference in melting point aroused by local heterogeneity in solutecontent.Theβdendrite is composed of numerous subgrains with various orientations.During quenching,theβdendrite transforms into Widmanstättenαvia a precipitation reaction,owing to the decreasing cooling rate caused by heat transfer from the surrounding liquid.Additionally,after quenching,the interdendritic liquid is transformed intoγplates.Within the singleβphase field and the lower part of the mushy zone,a massive transformation ofβtoγoccurs.Conversely,in theβ+αphase field,bothβandαphases are retained to ambient temperature.During the heating process,the transformation ofα→βgives rise to the formation ofβvariants,which affects the orientation ofβdendrites in the mushy zone.The growth kinematics of theα→βtransformation was elucidated,revealing the preferential growth directions of111and112forβvariants.Furthermore,this study presents an illustration of the formation process of the mushy zone and the microstructural evolution during the heating and quenching process. 展开更多
关键词 Titanium aluminides Mushy zone Quenching Electron backscattering diffraction Phase transformation
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Seismic detection of the X-discontinuity beneath the Ryukyu subduction zone from the SdP conversion phase 被引量:2
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作者 QingHui Cui WenLan Li +3 位作者 GuoHui Li MaiNing Ma XiaoYu Guan YuanZe Zhou 《Earth and Planetary Physics》 2018年第3期208-219,共12页
The X-discontinuity,which appears at the depth of approximately 300 km,is an important seismic interface with positive velocity contrasts in the upper mantle.Detecting its presence and topography can be useful to unde... The X-discontinuity,which appears at the depth of approximately 300 km,is an important seismic interface with positive velocity contrasts in the upper mantle.Detecting its presence and topography can be useful to understand phase transformations of relevant mantle minerals under the high-temperature and high-pressure circumstance of the Earth's interior.In this study,we detect the X-discontinuity beneath the Ryukyu subduction zone using five intermediate-depth events recorded by the dense Alaska Regional Network(AK).The X-discontinuity is successfully revealed from the robust slant stacking of the secondary down-going and converting Sd P phases.From the depth distribution of conversion points,we find that the X-discontinuity's depth ranges between 269 km and 313 km,with an average depth of 295 km.All the conversion points are located beneath the down-dipping side of the Philippine Sea slab.From energy comparisons in vespagrams for observed and synthetic seismograms,the strong converted energy is more likely from a thin high-velocity layer,and the S-wave velocity jumps across the X-discontinuity are up to 5% to 8% with an average of 6.0%.According to previous petrological and seismological studies,the X-discontinuity we detected can be interpreted as the phase transformation of coesite to stishovite in eclogitic materials within the oceanic crust. 展开更多
关键词 Ryukyu subduction zone X-discontinuity coesite-stishovite transformation dense network SDP CONVERSION PHASE
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On the generation of deep focus earthquakes in subduction zones 被引量:1
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作者 宁杰远 臧绍先 《Acta Seismologica Sinica(English Edition)》 CSCD 1999年第5期573-583,共11页
Following a quasi-dynamic scheme proposed by Minear and Toksoz (1970), thermal structures of subduction zonesfor different models by finite element method (FEM) were calculated. Density distribution and p-wave anomaly... Following a quasi-dynamic scheme proposed by Minear and Toksoz (1970), thermal structures of subduction zonesfor different models by finite element method (FEM) were calculated. Density distribution and p-wave anomaly ofsubduction zones were calculated at the same time. Comparing with seismological evidences and results of laboratories. it is proposed that earthquakes occurred below 400 km depth are probably controlled by anti-crackmechanism. 展开更多
关键词 subduction zone numerical simulation phase transformation generation of earthquakes anticrack theory
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In-situ nitrogen fate in the vadose zone of different soil types and its implications for groundwater quality in the Huaihe River Basin,China 被引量:1
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作者 Rongfu Li Xiaohong Ruan +2 位作者 Tianhai Ma Ying Bai Congqiang Liu 《Acta Geochimica》 EI CAS CSCD 2020年第3期281-290,共10页
This paper focused on nitrate fate in the vadose zone(VZ)and its implications for groundwater vulnerability under different soil types in the agricultural area of Huaihe River Basin,China.Isotopic compositions of nitr... This paper focused on nitrate fate in the vadose zone(VZ)and its implications for groundwater vulnerability under different soil types in the agricultural area of Huaihe River Basin,China.Isotopic compositions of nitrate(δ15N andδ18O)along with NO3-and Cl-concentrations were determined in the VZ-shallow groundwater continuum beneath silty-loam and silty-clay-loam,which are distinctive in texture and organic carbon(OC).In the soil zone(<1 m in depth),measuredδ18O-NO3-suggested the ubiquitous of nitrification regardless of soil types.In the subsoil zone(>1 m in depth),however,the concurrent enrichment ofδ15N-NO3-andδ18O-NO3-indicated the occurrence of denitrification,which showed a dependence on subsoil properties.Specifically,during wheat and maize land uses,denitrification removed as much as 76%-88%of the total nitrate where the subsoil was dominated by stratified OC-rich silty-clay-loam.In contrast,only 0%-28%of the nitrate was degraded via denitrification where the subsoil was composed of uniform,OC-depleted silty-loam.Furthermore,inactive denitrification and higher permeability in the silty-loam VZ implied higher groundwater vulnerability.This observation was consistent with the fact that groundwater NO3--N concentration beneath silty-loam(11.24 mg L-1)was over two times higher than that of the silty-clay-loam(5.32 mg L-1),where stricter fertilization management and conservation strategies should be applied to protect groundwater quality. 展开更多
关键词 Vadose zone Silty-loam Silty-clay-loam Nitrogen transformation Groundwater vulnerability Stable isotopes
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Topography of the 660-km discontinuity within the Izu-Bonin subduction zone and evidence of slab penetration near the Bonin Super Deep Earthquake(~680 km) 被引量:1
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作者 Gang Hao 《Earthquake Science》 2023年第6期458-476,共19页
The Izu-Bonin subduction zone in the Northwest Pacific is an ideal location for understanding mantle dynamics such as cold lithosphere subduction. The slab produces a lateral thermal anomaly, inducing local topographi... The Izu-Bonin subduction zone in the Northwest Pacific is an ideal location for understanding mantle dynamics such as cold lithosphere subduction. The slab produces a lateral thermal anomaly, inducing local topographic changes at the boundary of a post-spinel phase transformation, considered to be the origin of the ‘660-km discontinuity.’ In this study, the short-period(1–2 Hz) S-to-P conversion phase S660P was used to obtain the fine-scale structure of the discontinuity. More than 100 earthquakes that occurred from the 1980s to the 2020s and were recorded by high-quality seismic arrays in the United States and Europe were analyzed. A discontinuity in the ambient mantle with an average depth of ~670 km was found beneath the 300–400-km event zone in the northern Bonin region near 33°N. Meanwhile, the ‘660-km discontinuity’ has been pushed upward, away from the slab, possibly because of a hot upwelling mantle plume. In the central part of the subduction zone, the 660-km discontinuity is depressed to an average depth of(690 ± 5) km within the slab at approximately 150 km below the coldest slab core, indicating a(300 ± 100) ℃ cold anomaly estimated using a post-spinel transformation Clapeyron slope of(-2.0 ± 1.0) MPa/K. In southern Bonin near 28°N, the discontinuity was found to be further depressed at an average depth of(695 ± 5) km below the deepest event and with a focal depth of ~550 km. The discontinuity is located where the slab bends abruptly to become sub-horizontal toward the west-southwest. Near the zone of the isolated Bonin Super Deep Earthquake, which occurred at ~680 km on May 30,2015, the discontinuity is depressed to ~700 km, suggesting a near-vertical penetrating slab and an S-to-P conversion in the coldest slab core, where a large low-temperature anomaly should exist. 展开更多
关键词 Izu-Bonin subduction zone DISCONTINUITY post-spinel transformation S-to-P wave conversion vertical subduction cold slab
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大陆横向转换构造及其地质作用 被引量:1
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作者 刘池洋 黄雷 +4 位作者 赵红格 王建强 杨丽华 席晓东 彭恒 《地质学报》 EI CAS CSCD 北大核心 2024年第12期3455-3477,共23页
大陆横向转换构造(带)存在普遍,发育在大陆演化的不同阶段和各种不同的地球动力环境中。通常为一形态不规则、结构复杂的构造带;可定义为:在走向上与区域优势构造线近于垂直或大角度斜交的构造;其相邻两侧地质特征和构造变形差异明显。... 大陆横向转换构造(带)存在普遍,发育在大陆演化的不同阶段和各种不同的地球动力环境中。通常为一形态不规则、结构复杂的构造带;可定义为:在走向上与区域优势构造线近于垂直或大角度斜交的构造;其相邻两侧地质特征和构造变形差异明显。根据其形成环境、结构构造特征和地质作用等的不同,将横向转换构造(带)分为4类:变换(断裂)带、调节(构造)带、继接-传递带及岩浆-热力构造。不同类型和不同级别横向转换构造的地质特征和地质作用明显有别。但其间仍有较多的共性特征:如存在普遍、貌不惊人;特征多样、复杂多变;破裂具走滑剪切(扭动、旋转)构造特性;同类同级构造近等间距展布等。这些个性和共性特征可作为判识和确定横向转换构造的线索与依据。横向转换构造(带)值得关注的地质作用是:重要的转换、调节、传递作用,显著的分区(段)效应,特别的建造、改造场所和地震易发地段。其成矿作用主要表现为:本身常为重要的成矿带、造成矿产赋存条件和成藏(矿)作用的分区(段)。横向转换构造这些显著的地质作用、特别的构造特征及其规模(级别),常与其发育的时限或相对时序有密切的关联。本文主要据发育时限(序)的不同,在前期既成先存、同期转换调节、后期新生改造和加强三方面探讨了横向构造的成因机制。 展开更多
关键词 大陆横向转换构造(带) 变换(断裂)带 调节(构造)带 继接-传递带 岩浆-热力构造 分区作用 地质-成矿作用 成因机制
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Analysis of Dynamic Characteristics of Crustal Horizontal Deformation in the South Segment of Longmenshan Fault Zone Revealed by GPS Data after the Wenchuan Earthquake
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作者 Xiong Xiaohui Jiang Zaisen +2 位作者 Wu Yanqiang Wang Qixin Li Shengle 《Earthquake Research in China》 CSCD 2016年第1期43-56,共14页
In order to obtain deformation parameters in the south segment of Longmenshan fault zone,Euler datum transformation and the least square collocation for data interpolation and smoothing are used to process GPS displac... In order to obtain deformation parameters in the south segment of Longmenshan fault zone,Euler datum transformation and the least square collocation for data interpolation and smoothing are used to process GPS displacement time series data in the south segment of Longmenshan fault zone,and the rigid and elastic-plastic block motion model is used to calculate the strain parameters in each subarea. Conjoint analysis of displacement,velocity of each station and strain parameters of each subarea reveals that the influence of the Wenchuan earthquake on the south segment of Longmenshan fault zone increases from southeast to northwest,causing a highest deformation rate 6 times the background value and heightening the influence of the hidden faults on the difference of the earth surface along its two sides,which leads to the seismic risk of the southern segment increasing from north to south. The comparison of seismic risk among subareas based on the tectonic and seismicity background indicates that the most dangerous area is on the southeast of Longmenshan faults,and the background strain accumulation and the promoting effect of the Wenchuan earthquake advanced the occurrence of Lushan earthquake and the sinistral strike-slip on the rupture plane. The Wenchuan earthquake also caused a slight two-year long continuous strain release in the south segment of Xianshuihe fault,but the influence is far less than the effect of the compressive strain caused by the Sichuan-Yunnan block. 展开更多
关键词 South segment of Longmenshan fault zone the Wenchuan earthquake GPStime series The Least Square Collocation Euler transform Strainparameters Lushan earthquake
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个体化LEEP手术设计对宫颈鳞状上皮内病变患者切缘及疾病预后的影响
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作者 刘婷艳 王伟嘉 +3 位作者 廖惠明 麦碧 胡桂英 罗喜平 《国际医药卫生导报》 2024年第21期3594-3600,共7页
目的本研究旨在探讨个体化宫颈锥切手术设计与切缘状况及宫颈病变预后之间的关系。方法收集2015年1月至2019年12月在广东省妇幼保健院门诊因宫颈高级别鳞状上皮内病变(HSIL)行宫颈环形电切术(LEEP)的151例患者进行回顾性研究,年龄(35.54... 目的本研究旨在探讨个体化宫颈锥切手术设计与切缘状况及宫颈病变预后之间的关系。方法收集2015年1月至2019年12月在广东省妇幼保健院门诊因宫颈高级别鳞状上皮内病变(HSIL)行宫颈环形电切术(LEEP)的151例患者进行回顾性研究,年龄(35.54±7.29)岁,其中有生育要求60例、无生育要求91例。术前阴道镜医师在全面、准确阴道镜评估基础上结合宫颈细胞学、宫颈活检病理等因素对患者分别进行个体化LEEP手术设计,收集术后标本内切缘状况、宫颈口粘连狭窄及2年内复查人乳头瘤病毒(HPV)检测结果。多因素logistic回归分析影响LEEP手术标本内切缘状况的相关因素,以及不同切缘状况、手术方式与疾病预后之间的关系,探讨个体化LEEP手术设计的可行性和有效性。统计学方法采用t检验、χ^(2)检验、Fisher确切概率法检验。结果151例行LEEP手术患者内切缘阳性20例,内切缘阴性131例,切缘阳性率为13.25%。无生育要求患者锥切长度、锥切厚度均大于有生育要求患者[(1.18±0.34)cm比(0.93±0.21)cm、(1.11±0.45)cm比(0.90±0.33)cm],且“一刀切”的LEEP手术占比低于有生育要求患者[75.8%(69/91)比91.7%(55/60)],差异均有统计学意义(t=5.680、3.459,χ^(2)=6.181;均P<0.05);两组内切缘阳性率比较,差异无统计学意义(P>0.05)。单因素分析结果显示,术前宫颈细胞学、阴道镜下醋白上皮累及象限数、术前活检病变级别与LEEP手术标本内切缘状况具有相关性(均P<0.05)。多因素logistics回归分析结果显示,阴道镜下醋白上皮累及象限数、术前活检病变级别是影响LEEP术后标本内切缘的独立危险因子(均P<0.05)。术后随访2年HPV总转阴率为82.7%(124/150)。不同内切缘状况患者随访数据表明,术后宫颈口狭窄及术后6个月、12个月、24个月HPV检测结果比较,差异均无统计学意义(均P>0.05)。结论以患者生育要求为前提,在全面准确阴道镜评估基础上结合患者宫颈细胞学及病变级别等因素进行个体化的锥切手术设计,临床上是可行且有效的,尤其是对有生育要求的女性更具临床价值。 展开更多
关键词 宫颈高级别鳞状上皮内病变 人乳头瘤状病毒 宫颈环形电切术 内切缘 转化区
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