The geochronological works for the Hannan intrusive complex, cosisting of the gabbro-quartz dio-rite-plagiogranite bodies, in the north border of the Yangtze craton block, adjoining the Qinling orogen, are reported, b...The geochronological works for the Hannan intrusive complex, cosisting of the gabbro-quartz dio-rite-plagiogranite bodies, in the north border of the Yangtze craton block, adjoining the Qinling orogen, are reported, because its age and genesis are of great importance to research of the tectonic evalutional history for the Qinling orogen and of the rifted processes for the Late Proterozoic supercontinent Rodinia. A good isochron of t=(837±26) Ma (2σ), corresponding to INd=0.51165±2(2σ), εNd(t)=+1.9, MSWD1.02, was difined by the Nd isotopic analytical results for the 21 whole-rock samples from the varied lithological complex bodies, but for the Rb-Sr isotopic aralytical data there is no isochron. The 40Ar/39Ar plateau age of the biotite, sorted from plagiogranites, is (796±20) Ma(2σ), and yet for the Rb-Sr isotopic data of the plagiogranite whole-rock samples (WR) and the sorted biotite (Bio), plagioclase (Plag) and apatite (Apt) mineral samples from the plagiogranitewhole-rock samples, an展开更多
For a large-scale array,its realized gain is always smaller than the summation of the element gains in isolation,which is the well-known gain paradox proposed by Hannan.To explain the paradox,embedded element efficien...For a large-scale array,its realized gain is always smaller than the summation of the element gains in isolation,which is the well-known gain paradox proposed by Hannan.To explain the paradox,embedded element efficiency(EEE)was defined to indicate whether the array elements are being fully utilized,and Hannan’s limit was introduced to provide a fundamental upper bound of the EEE.In this paper,Hannan’s limit is extended to assess the beam-scanning capability of a phased array,which can provide a fundamental upper bound of the EEE corresponding to different scanning angles.In addition,the methods for enhancing the EEE of a large-scale array to approach Hannan’s limit are discussed,including selecting an appropriate power pattern for the array element and efficiently decoupling the array elements.For verification,a planar large-scale wide-angle scanning array utilizing a hybrid decoupling strategy is designed in this paper.The proposed decoupling structure improves the isolation between adjacent array elements in both the E-plane and H-plane by approximately 18.3 dB.The beam-scanning range in the E-plane and H-plane can±65°±60°reach and.During beam scanning,the realized gain of the array can be improved by approximately 0.74 dB.After decoup-×ling,the EEE of the 88 wide-angle scanning array can be improved by approximately 12.64%on average during beam scanning,which is closer to Hannan’s limit.展开更多
Lying at the junction of the Dabashan, Longmenshan and Qinling mountains, the Micangshan Orogenic Belt coupled with a basin is a duplex structure and back-thrust triangular belt with little horizontal displacement, sm...Lying at the junction of the Dabashan, Longmenshan and Qinling mountains, the Micangshan Orogenic Belt coupled with a basin is a duplex structure and back-thrust triangular belt with little horizontal displacement, small thrust faults and continuous sedimentary cover. On the basis of 3D seismic data, and through sedimentary and structural research, the Micangshan foreland can be divided into five subbelts, which from north to south are： basement thrust, frontal thrust, foreland depression-back-thrust triangle, foreland fold belt or anticline belt, and the Tongjiang Depression. Along the direction of strike from west to east, the arcuate structural belt of Micangshan can be divided into west, middle and east segments. During the collision between the Qinling and Yangtze plates, the Micangshan Orogenic Belt was subjected to the interaction of three rigid terranes： Bikou, Foping, and Fenghuangshan （a.k.a. Ziyang） terranes. The collision processes of rigid terranes controlled the structural development of the Micangshan foreland, which are： （a） the former collision between the Micangshan-Hannan and Bikou terranes forming the earlier rudiments of the structure; and （b） the later collision forming the main body of the structural belt. The formation processes of the Micangshan Orogenic Belt can be divided into four stages： （1） in the early stage of the Indosinian movement, the Micangshan-Hannan Rigid Terrane was jointed to the Qinling Plate by the clockwise subduction of the Yangtze Plate toward the Qinling Plate; （2） since the late Triassic, the earlier rudiments of the Tongnanba and Jiulongshan anticlines and corresponding syncline were formed by compression from different directions of the Bikou, Foping and Micangshan-Hannan terranes; （3） in the early stage of the Himalayan movement, the Micangshan-Hannan Terrane formed the Micangshan Nappe torwards the foreland basin and the compression stresses were mainly concentrated along both its flanks, whereas the Micangshan-Hannan Terrane wedged into the Qinling Orogenic Belt with force; （4） in the late stage of the Himalayan movement, the main collision of the Qinling Plate made the old basement rocks of the terrane uplift quickly, to form the Micangshan Orogenic Belt. The Micangshan foreland arcuate structure was formed due to the non-homogeneity of terrane movement.展开更多
基金the NationalNatural Science Foundation of China (Grant Nos. 49732080 and 49773182).
文摘The geochronological works for the Hannan intrusive complex, cosisting of the gabbro-quartz dio-rite-plagiogranite bodies, in the north border of the Yangtze craton block, adjoining the Qinling orogen, are reported, because its age and genesis are of great importance to research of the tectonic evalutional history for the Qinling orogen and of the rifted processes for the Late Proterozoic supercontinent Rodinia. A good isochron of t=(837±26) Ma (2σ), corresponding to INd=0.51165±2(2σ), εNd(t)=+1.9, MSWD1.02, was difined by the Nd isotopic analytical results for the 21 whole-rock samples from the varied lithological complex bodies, but for the Rb-Sr isotopic aralytical data there is no isochron. The 40Ar/39Ar plateau age of the biotite, sorted from plagiogranites, is (796±20) Ma(2σ), and yet for the Rb-Sr isotopic data of the plagiogranite whole-rock samples (WR) and the sorted biotite (Bio), plagioclase (Plag) and apatite (Apt) mineral samples from the plagiogranitewhole-rock samples, an
基金National Natural Science Foundation of China(Grant No.U2141230).
文摘For a large-scale array,its realized gain is always smaller than the summation of the element gains in isolation,which is the well-known gain paradox proposed by Hannan.To explain the paradox,embedded element efficiency(EEE)was defined to indicate whether the array elements are being fully utilized,and Hannan’s limit was introduced to provide a fundamental upper bound of the EEE.In this paper,Hannan’s limit is extended to assess the beam-scanning capability of a phased array,which can provide a fundamental upper bound of the EEE corresponding to different scanning angles.In addition,the methods for enhancing the EEE of a large-scale array to approach Hannan’s limit are discussed,including selecting an appropriate power pattern for the array element and efficiently decoupling the array elements.For verification,a planar large-scale wide-angle scanning array utilizing a hybrid decoupling strategy is designed in this paper.The proposed decoupling structure improves the isolation between adjacent array elements in both the E-plane and H-plane by approximately 18.3 dB.The beam-scanning range in the E-plane and H-plane can±65°±60°reach and.During beam scanning,the realized gain of the array can be improved by approximately 0.74 dB.After decoup-×ling,the EEE of the 88 wide-angle scanning array can be improved by approximately 12.64%on average during beam scanning,which is closer to Hannan’s limit.
基金These research results are part of a key project carried out in 2005-2007 and financially supported by the Natural Science Foundation of China (No.40472110).
文摘Lying at the junction of the Dabashan, Longmenshan and Qinling mountains, the Micangshan Orogenic Belt coupled with a basin is a duplex structure and back-thrust triangular belt with little horizontal displacement, small thrust faults and continuous sedimentary cover. On the basis of 3D seismic data, and through sedimentary and structural research, the Micangshan foreland can be divided into five subbelts, which from north to south are： basement thrust, frontal thrust, foreland depression-back-thrust triangle, foreland fold belt or anticline belt, and the Tongjiang Depression. Along the direction of strike from west to east, the arcuate structural belt of Micangshan can be divided into west, middle and east segments. During the collision between the Qinling and Yangtze plates, the Micangshan Orogenic Belt was subjected to the interaction of three rigid terranes： Bikou, Foping, and Fenghuangshan （a.k.a. Ziyang） terranes. The collision processes of rigid terranes controlled the structural development of the Micangshan foreland, which are： （a） the former collision between the Micangshan-Hannan and Bikou terranes forming the earlier rudiments of the structure; and （b） the later collision forming the main body of the structural belt. The formation processes of the Micangshan Orogenic Belt can be divided into four stages： （1） in the early stage of the Indosinian movement, the Micangshan-Hannan Rigid Terrane was jointed to the Qinling Plate by the clockwise subduction of the Yangtze Plate toward the Qinling Plate; （2） since the late Triassic, the earlier rudiments of the Tongnanba and Jiulongshan anticlines and corresponding syncline were formed by compression from different directions of the Bikou, Foping and Micangshan-Hannan terranes; （3） in the early stage of the Himalayan movement, the Micangshan-Hannan Terrane formed the Micangshan Nappe torwards the foreland basin and the compression stresses were mainly concentrated along both its flanks, whereas the Micangshan-Hannan Terrane wedged into the Qinling Orogenic Belt with force; （4） in the late stage of the Himalayan movement, the main collision of the Qinling Plate made the old basement rocks of the terrane uplift quickly, to form the Micangshan Orogenic Belt. The Micangshan foreland arcuate structure was formed due to the non-homogeneity of terrane movement.
