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61.
20世纪中国女性文学的女性意识经历了五四时期的暖昧期、30年代至70年代的消融期和80年代后觉醒张扬的超越期,渐渐走向成熟。这种变化是与时代的变化、社会的发展和妇女解放的步伐相一致的。 相似文献
62.
该文简要描述了Lennard-Jones(12,6)势能参数的HB、TW、FP、IGS等计算方法,并对上述计算结果的可靠性进行了讨论,认为IGS、FP的结果最为令人满意,TW公式次之,HB公式再次。最后,在综合前人工作的基础上,针对各种不同对象采用对各自适合的计算方法,列出了300种常见液态物质势能参数σ与ε/k的最佳值。 相似文献
63.
64.
赵世英 《山东科技大学学报(自然科学版)》1986,(4)
郯庐断裂带是我国东部的一条巨型断裂带。在山东境内是不同大地构造单元的分界线,使东西两侧的深部、基底和盖层在地质和地球物理方面,都有很大的差异。该断裂成生于太古代中期,并开始对两侧的沉积与剥蚀起控制作用。在长期的活动中,表现出间歇性、继承性和差异性。运动特点则主要以差异升降为主,没有发生大规模的水平运动。 相似文献
65.
Deep crustal structure of Baiyun Sag,northern South China Sea revealed from deep seismic reflection profile 总被引:15,自引:0,他引:15
HUANGChunju ZHOUDi SUNZhen CHENChangmin HAOHujun 《科学通报(英文版)》2005,50(11):1131-1138
This paper discusses deep crustal architecture of the Baiyun Sag of the Pearl River Mouth Basin, northern South China Sea based on velocity analysis, time-depth conversion and seismic interpretation of the deep seismic reflection profile DSRP-2002. The profile was acquired and processed to 14 S TWT by the China National Offshore Oil Corp. (CNOOC) in 2002. It extends across the Baiyun Sag of the Pearl River Mouth Basin, from the northern continental shelf of the SCS to the deepwater province. As the first deep seismic reflection profile in the Pearl River Mouth Basin, this profile reveals seismic phases from basement down to upper most mantle. The Moho surface appears in the profile as an undulating layer of varying thickness of 1-3 km. It is not a single reflector interface, but a velocity gradient or interconversion layer. The crust thins stepwisely from the shelf to the continental slope and the abyssal plain (from north to south), and also thins under depocenters. The crustal thickness is only 7 km in the depocenter of the main Baiyun Sag, which corresponds to a Moho upwelling mirroring the basement topography. In the lower slope and the ocean-continental transition zone of the southernmost portion of the profile, three sub-parallel, NW-dipping strong reflectors found at depths around 10--21 km are interpreted as indications of a subducted Mesozoic oceanic crust. Crustal faults exist in the northern and southern boundaries of the Baiyun Sag. The intense and persistent subsidence of the Baiyun Sag might be related to the long-term activity of the crustal faults. 相似文献
66.
Opening and evolution of the South China Sea constrained by studies on volcanic rocks: Preliminary results and a research design 总被引:8,自引:0,他引:8
The South China Sea (SCS) is characterized by abundant seamounts, which provide important information about the evolution of the SCS and related deep processes. Cenozoic volcanism in the SCS and its surroundings comprises three stages relative to the spreading of the SCS:prespreading (>32 Ma), syn-spreading (32-16 Ma), and post-spreading (<16 Ma). The pre-spreading magmatism predominantly occurs on the northern margin of the SCS and in South China coastal areas and shows a bi-modal affinity. The syn-spreading magmatic activity was very limited on the periphery of the SCS, but may be concentrated in the SCS. However, seafloor samples of this stage are not available yet because of overlying thick sedimentary deposits. Post-spreading magmatism is widespread in the central and southwest sub-basins of the SCS, Hainan Island, Leizhou Peninsula, Thailand, and Vietnam. These are mainly alkali basalts with subordinate tholeiites, and display OIB-type geochemical characteristics. The Dupal isotope anomaly and presence of high-magnesian olivine phenocrysts suggests their possible derivation from the Hainan mantle plume. The temporal and spatial distribution of Cenozoic volcanism in the SCS and its surroundings may be accounted for either by plate stress re-organization before and after SCS spreading, or by ridge suction of plume flow during opening of the SCS. If the latter is the case, the volcanic rocks within the SCS basin may not be typical mid-ocean ridge basalts (MORB). It remains puz-zling, however, that the transition between the South China continental margin and the SCS basin does not have features typical of a volcanic rifted margin. Clearly, the relationship between mantle plume and SCS opening needs further evaluation. A better un-derstanding of the link between deep processes and opening of the SCS not only requires enhanced studies on igneous petrogene-sis, but also is heavily dependent on systematic sampling of seafloor rocks. 相似文献
67.
Petrogenesis of Aoyougou high-silica adakite in the North Qilian orogen, NW China: Evidence for decompression melting of oceanic slab 总被引:2,自引:0,他引:2
A trondhjemitic body occurs in the Aoyougou area,the western part of the North Qilian orogen.It is geochemically characterized by high SiO 2,Na 2 O (high Na/K),elevated Sr/Y and (La/Yb) N,positive Sr anomaly,relatively enriched large ion lithophile elements (LILEs) and light rare earth elements (LREEs),and depleted Nb,Ta,Ti,resembling the high-silica adakite.Zircon U-Pb SHRIMP dating yields a weighted mean age of 438±3 Ma.This age is significantly younger than eclogitization ages of 460-490 Ma in the North Qilian orogen,suggesting that formation of the adakite postdates the subduction of oceanic crust in association with closure of the ancient Qilian Ocean.Whole-rock Sr and Nd isotopic analyses give initial ratios of I Sr =0.7044 0.7047 and Nd (t)=3.0 4.1,indicating that they are derived from partial melting of the juvenile oceanic crust.In view of the tectonic evolution of the North Qilian orogen,the high-silica adakite was probably derived from decompression melting of the exhumed eclogite at the depth of ~60 km. 相似文献
68.
Eocene high grade metamorphism and crustal anatexis in the North Himalaya Gneiss Domes,Southern Tibet 总被引:13,自引:0,他引:13
Determination of the timing and geochemical nature of early metamorphic and anatectic events in the Himalayan orogen may provide key insights into the physical and chemical behavior of lower crustal materials during the early stage of tectonic evolution in large-scale collisional belts.The Yardoi gneiss dome is the easternmost dome of the North Himalayan Gneiss Domes(NHGD),and contains three types of amphibolites with distinct mineral assemblage,elemental and radiogenic isotope geochemistry,as well as various types of gneisses.SHRIMP zircon U/Pb analyses on the garnet amphibolite and garnet-bearing biotite granitic gneiss yield ages of nearly peak metamorphism at 45.0±1.0 Ma and 47.6±1.8 Ma,respectively,which are 2 to 4 Ma older than the age for partial melting in migmatitic garnet amphibolite(43.5±1.3 Ma).Available data have demonstrated that ultra-high pressure metamorphism in the Tethyan Himalaya occurred at ~55 Ma,and high amphibolite facies to granulite facies metamorphism at 45 to 47 Ma.In addition,partial melting at thickened crustal conditions occurred at 43.5±1.3 Ma,which led to the formation of high Sr/Y ratios two-mica granites.The high-grade metamorphic rocks in the NHGD may represent the subducted front of the Indian continental lithosphere.In large collisional belts,fertile components in crustal materials could melt and form granitic melts with relatively high Na/K and Sr/Y ratios under thickened crustal conditions,significantly different from those formed by decompressional melting during rapid exhumation. 相似文献
69.
核磁共振成像原位监测冰融化及四氢呋喃水合物分解的微观过程 总被引:2,自引:0,他引:2
核磁共振成像(Magnetic Resonance Imaging,MRI)可以通过物质在不同相态之间的亮度差别来识别物质相态的变化,冰、水和水合物之间较大的亮度对比使MRI成为监测水合物生成分解动态过程的有效工具.采用MRI原位监测了冰融化和四氢呋喃(THF)水合物分解的微观过程,从微观角度对比研究了THF水合物分解与冰融化过程的异同.冰融化和THF水合物的分解过程受传热程控,冰的融化和水合物的分解总是沿着固-液界面从外向内推进,消解速度持续加快.固相表面的"结构化水层"是冰和水合物立体结构瓦解的主要原因.THF水合物的分解过程与气体水合物不同,没有明显的"自保护效应".由于温度梯度产生的密度差异,液相产生自然对流,造成了水合物的分解及冰的融化过程中固-液界面运动的随机性. 相似文献
70.
粉末特性与工艺参数对SLM成形的影响 总被引:1,自引:0,他引:1
通过试验研究了316L不锈钢粉末参数及工艺参数对选择性激光熔化(SLM)成形性能的影响规律.结果表明:单一粒径分布的粉末松装密度低于多种粒径混合后的松装密度;采用2种不同粒径粉末充分混合,最大松装密度达到59.83%;平均粒径小的粉末比平均粒径大的粉末成形性好,粒径分布范围宽的粉末成形时球化现象明显;利用平均粒径为26.36p.m的粉末和优化的工艺参数制造出测试件,最高致密度达99.75%,拉伸强度最高达1068MPa. 相似文献