检索结果-南通市图书馆

Coherent variations of the obliquity components in global ice volume and ocean carbon reservoir over the past 5 Ma

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2013年第12期56卷 2160-2172页

作者： tian jun State Key Laboratory of Marine Geology Tongji University

The Milankovid theory stresses that the summer insolation in the high northern latitudes that is dominated by the precession cycle controls the glacial/interglacial cycles in global climate change. If the climate system responds linearly to the external insolation forcing, the precession cycle of 23 or 19 ka should dominate the variations in the climatic proxy records. I per- formed spectral and evolutive cross spectral analyses on the high resolution benthic ~80 and oa3C records from the South China Sea and the North Atlantic, the proxies of global ice volume and ocean carbon reservoir respectively. I found that the obliquity instead of the eccentricity or the precession is the most marked cycle in the global ice volume and ocean carbon res- ervoir variations over the past 5 Ma. The analysis further reveals that only at the obliquity band instead of the eccentricity or the precession band does the global ice volume and ocean carbon reservoir display consistently high coherency and stable phase relationship over the past 5 Ma. The consistently positive or near-zero phases of the benthic -o^SO relative to the benthic ff3C at the obliquity band suggest that the global carbon cycle is involved in the polar ice sheet growth as an important internal feedback, not a determinative driving factor. The obliquity instead of the precession or the eccentricity takes the dominant role of driving the global climate change during the Pliocene and Pleistocene.

关键词： global ice volume ocean carbon reservoir obliquity 5 Ma

Stability of Nonlinear Wave of Kadomtsev-Petviashvili-Type Equation

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2007年第2期47卷 333-338页

作者： FENG tian-jun Department of Physics Lanzhou Jiao Tong University Lanzhou 730070 China

For ion-acoustic waves in a plasma with non-isothermal electrons, the MKP equation is its governing equation. The instability of a soliton solution of MKP equation to two-dimensional long-wavelength perturbations is investigated up to the third order. It indicates that the one-soliton solution of MKP equation is unstable if v = -1 wheras it is stable if v = 1 until the third order approximation has been considered.

关键词： MKP equation stability solitary waves

Warming magnitude of Indonesian Throughflow during the penultimate deglaciation (Termination Ⅱ) and its relationship with climate change in high-latitude regions

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2010年第32期55卷 3709-3717页

作者： tian CuiCui tian jun State Key Laboratory of Marine Geology Tongji University Shanghai 200092 China

The tropical oceans are important source areas for global heat and water vapor transport,and changes in tropical sea surface temperature (SST) will have important impacts on high-latitude and global climate change. It is crucial to establish the precise phase relationship between tropical and high-latitude climate variability to gain insight into the mechanisms of global climate change. Here,we present multi-proxy records across the penultimate deglaciation (Termination Ⅱ) from sediment Core SO18459,which is located in the outflow area of the Indonesian Throughflow (ITF) of the Timor Sea. These proxy records include planktonic and benthic foraminifera δ 18O,planktonic foraminifera G. ruber Mg/Ca-derived SST,and δ18Ow of sea surface water. The Mg/Ca-SST records indicate a warming of 4.1°C in the Timor Sea over Termination Ⅱ,which is in phase with decrease in planktonic and benthic δ18O. Our results suggest that at millennial timescales,climate change of the tropical oceans is synchronous with high-latitude ice volume changes. Furthermore,warming of the Timor Sea is almost simultaneous with warming of the Antarctic,suggesting a rapid heat transfer from the tropics to the Antarctic via the atmosphere and/or ocean circulations. The G. ruber δ18O and SST records of Core SO18459 show a marked YD-like event during Termination Ⅱ,which is probably caused by decrease in Australian rainfall or strengthening of the Western Pacific Warm Pool. However,a similar YD-like event is not observed in East Asian rainfall records. This discrepancy indicates that different tropical climate systems may have different responses to the same forcing,such as El Nio Southern Oscillation. A similar YD-like event is observed in the global benthic foraminiferal δ18O records during Termination Ⅱ,implying teleconnection of millennial scale climate change between the tropical regions and high latitudes.

关键词：印度尼西亚贯穿流高纬度地区气候变暖冰消期倒数全球气候变化热带海洋底栖有孔虫

Dissipation of Nonlinear Wave in Inhomogeneous Dust Plasma Crystal

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2009年第11期52卷 941-944页

作者： FENG tian-jun Department of Physics Lanzhou Jiao Tong University Lanzhou 730070 China

A Korteweg-de Vires-type （KdV-type） equation and a modified Nonlinear Schrodinger equation （NLSE） for the dust lattice wave （DLW） are derived in a weakly inhomogeneous dust plasma crystal. It seems that the amplitude and the velocity of the dust lattice solitary waves decay exponentiaJly with increasing time in a dust lattice. The modulational instability of this dust lattice envelope waves is investigated as well. It is found that the waves are modulational stable under certain conditions. On the other hand, the waves are modulationaJ unstable if the conditions are not satisfied.

关键词： reductive perturbation method dust lattice wave

The hardest transition metal nitride predicted from machine learning

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2018年第15期63卷 947-948页

作者： Yong, jun tian Center for High Pressure Science. State Key Laboratory of Metastable Materials Science and Technology Yanshan University Qiahuangdaa 066004 China

Materials that possess Vickers hardness(Hv)higher than 40 GPa are known as superhard materials,which have important applications in industry and scientific ***,there are only two types of superhard materials,*** and cubic boron nitride(c-BN),which are widely used as cutting,polishing,drilling and coating *** diamond has unrivaled hardness of 60–120 GPa,its applications in some circumstances,such as cutting ferrous materials,are limited due to poor

关键词：金属氮化物机器学习涂层材料预言科学研究

Interactively Inspection Layers of CT Datasets on CUDA-Based Volume Rendering

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2015年第2期24卷 355-360页

作者： LUO Yanhong tian jun LUO Yanlin The School of Nuclear Science and Technology Lanzhou University The College of Electrical Engineering Northwest University for Nationalities The School of Biomedical Engineering Xinjiang Medical University Institute of Virtual Reality and Visualization Technology Beijing Normal University

With the fast growing size and dimensionality of scientific datasets, inspection and rendering data features has become an important topic when traversing through it. We propose opacity transfer function with trapezoid shape having an overlapping region to extract different layers when using Compute unified device architecture(CUDA)-based volume ray-casting. We define different tools such as probe for 3D inspection and virtual lenses for 2D inspection of inner layers in Region-ofinterest(ROI). We verify the effectiveness which allowing inspection of structures both interior layers in ROI and exterior semi-transparent ones at interactive frame rates.

关键词： Volume inspection Volume rendering Opacity transfer function Volume interaction

MIXED LEGENDRE-HERMITE PSEUDOSPECTRAL METHOD FOR HEAT TRANSFER IN AN INFINITE PLATE

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2005年第6期23卷 587-602页

作者： tian-jun Wang Ben-yu Guo Department of Mathematics Division of Computational Science of E-institute of Shanghai Universities Shanghai Normal University Shanghai 200234 China

A new mixed Legendre-Hermite interpolation is introduced. Some approximation results are established. Mixed Legendre-Hermite pseudospectral method is proposed for non-isotropic heat transfer in an infinite plate. Its ... 详细信息

关键词： Non-isotropic heat transfer Infinite plate Mixed Legendre-Hermite pseudospectral method

Mechanical properties and microstructure of Mg-treated and Catreated industrial H13 steel after quenching and tempering

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第8期31卷 1987-2001页

作者： jun-ying Yue Dong Hou De-yong Wang tian-peng Qu Xiang-long Li jun tian School of Iron and Steel Soochow UniversitySuzhou 215021JiangsuChina

The effect of magnesium treatment and calcium treatment on the microstructure and mechanical properties of industrial H13 steel after quenching and tempering was *** impact toughness and tensile tests were mainly carried out,and the microstructure was observed by scanning electron microscopy,electron backscattered diffraction,and X-ray *** results show that magnesium treatment is still feasible in industrial *** is mainly manifested in the refinement of lath martensite and *** with calcium treatment,the prior austenite grains and carbides size of industrial H13 steel treated with magnesium decreased by 3.17μm after *** quenching and tempering,the carbides(especially V-rich carbides)in Mg treatment obviously spheroidized and distributed uniformly and increased in quantity *** lath martensite size is reduced from 2.45 to 2.31μ*** suggests that magnesium treatment was able to yield smaller grains and more evenly distributed ***,the impact toughness,yield strength,and ultimate tensile strength of industrial H13 steel with magnesium treatment increased by 28%,65.5 MPa and 123.7 MPa,*** increment of strength mainly comes from dislocation strengthening,grain refinement strengthening,and precipitation strengthening,among which precipitation strengthening accounts for the largest proportion.

关键词： Industrial H13 steel Mg treatment Heat treatment Carbide-Mechanical property

Paleoenvironment and organic matter enrichment of the Carboniferous volcanic-related source rocks in the Malang Sag,Santanghu Basin,NW China

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Petroleum Science 2021年第1期18卷 29-53页

作者： tian-jun Li Zhi-Long Huang Xuan Chen Xin-Ning Li jun-tian Liu State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum(Beijing)Beijng 102249China College of Geosciences China University of Petroleum(Beijing)Beijing 102249China Research Institute of Exploration and Development PetroChina Tuha Oilfield CompanyHamiXinjiang 839009China

Volcanic activity was quite frequent during the deposition of the Late Carboniferous Ha’erjiawu Formation in the Santanghu *** petrology and organic and inorganic geochemical indicators were used to investigate hydrocarbon potential,paleoenvironmental conditions and organic matter enrichment of the *** results show that the oil generation capacity of the Ha’erjiawu Formation mudstones,which has abundant oil-prone organic matter(TypeⅡkerogen with hydrogen index values mainly ranging from 250 to 550 mg HC/g TOC)in mature stage(Tmax values mainly ranging from 435 to 450℃),is *** Ha’erjiawu Formation was deposited in a dysoxic,freshwater-mildly brackish,and warm-humid *** its deposition,the Ha’erjiawu Formation received hydrothermal *** volcanic hydrothermal activities played an important role in the organic matter *** addition,the total organic carbon(TOC)is significantly positively correlated with the felsic mineral content,but it is negatively correlated with the carbonate mineral content and C27/C29 ratios,indicating that terrigenous organic matter input also contributed to the primary productivity in the surface ***,the formation of the high-quality source rocks in the Ha’erjiawu Formation was jointly affected by the hydrothermal activity and the terrigenous organic matter input.

关键词： Organic-rich rocks Paleoenvironment Organic matter enrichment Hydrothermal activity Ha’erjiawu Formation Santanghu Basin