检索结果-南通市图书馆

Quantitative analysis of soil pores under natural vegetation successions on the Loess Plateau

Science china Earth sciences 2010年第4期53卷 617-625页

作者： ZHAO ShiWei1,ZHAO YongGang1,2.& WU JinShui3.1 State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Institute of Soil and Water Conservation,Northwest Agriculture & Forestry university,Yangling 712.00,{2. 2.graduate university of chinese Academy of sciences,Beijing 100049,{2. 3.Institute of Subtropical Agriculture,chinese Academy of sciences,Changsha 41012.,{2. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water Conservation Northwest Agriculture & Forestry University Yangling China graduate university of {2. Academy of {3. Beijing China Institute of Subtropical Agriculture Chinese Academy of Sciences Changsha China

Soil pore is a key attribute of the soil structure that affects soil reservoir under natural vegetation recovery on the Loess *** study is to quantitatively analyze soil pore parameters,measured with Computed Tomography(CT) at 15-57 mm depths under five different vegetation succession stages using a concept of substituting "space" for "time" in the Ziwuling Forest Region of the Loess *** results showed that the soil pore parameters,such as pore number,porosity,circularity,and fractal dimension,increased significantly under the natural vegetation successions and varied with the pattern climax community stage>pioneering arbor community stage>scrub community stage>herbaceous community stage>abandoned farmland stage,indicating that natural vegetation recovery could remarkably improve soil pore *** the vegetation succession,this positive effect will be strengthened gradually,which means that the soil pore parameters may appear to be best at the climax community *** organic matter content increased linearly with the soil pore parameters(P<0.001).Increased organic matter accumulation was one of the major reasons for the changes in soil pore characteristics in natural vegetation succession.

关键词： Computed Tomography Loess Plateau natural vegetation succession soil pore soil organic matter

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Narrow line Seyfert 1 galaxies: where are the broad line regions?

引用

Science china(Physics,Mechanics & Astronomy) 2010年第12期53卷 2307-2311,2339-2343页

作者： MAO WeiMing 1,2.3., HU Chen 2., WANG JianMin 2., BIAN WeiHao 4 , ZHANG Shu 2.& ZHAO Gang 1 1 Key Laboratory of Optical Astronomy, National Astronomical Observatories, chinese Academy of {2., Beijing 100012. china 2.Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, chinese Academy of {2., Beijing 100049, china 3.graduate university of the chinese Academy of {2., Beijing 100049, china 4 Department of Physics, Nanjing Normal university, Nanjing 2.0011, china chinese Academy of sciences Key Laboratory of Optical Astronomy National Astronomical Observatories Beijing China (GRID:grid.9227.e) (ISNI:***) chinese Academy of sciences Key Laboratory for Particle Astrophysics Institute of High Energy Physics Beijing China (GRID:grid.9227.e) (ISNI:***) graduate university of the {2. Academy of {3. Beijing China (GRID:grid.458514.9) chinese Academy of sciences Key Laboratory for Particle Astrophysics Institute of High Energy Physics Beijing China (GRID:grid.9227.e) (ISNI:***) Nanjing Normal university Department of Physics Nanjing China (GRID:grid.260474.3) (ISNI:***) chinese Academy of sciences Key Laboratory of Optical Astronomy National Astronomical Observatories Beijing China (GRID:grid.9227.e) (ISNI:***)

A sample consisting of 2.1 narrow line Seyfert 1 galaxies (NLS1s) with high quality spectra from the Sloan Digital Sky Survey (SDSS) is selected to explore where broad line regions are in these objects. We find that the Hβ profile can be fitted well by three (narrow, intermediate and broad) Gaussian components, and the FWHM ratios of the broad to the intermediate components hold a constant of 3.0 roughly for the entire sample. If the broad components originate from the region scaled by the well-determined Hβ reverberation mapping relation, we find that the intermediate components originate from the inner edge of the torus, which is scaled by dust K-band reverberation. We find that the IC and the BC are strongly linked dynamically, but the relation of their covering factors is much more relaxed, implying that both regions are clumpy.

关键词： black hole physics galaxies: evolution quasars: general

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Quaternary marine transgressions in eastern china

引用

Journal of Palaeogeography 2012年第2期1卷 105-125页

作者： Lin Jingxing1, 3. Dai Luping2. 3.1. Institute of Geology, {2. Academy of Geological sciences, Beijing 10003., china 2. Key Laboratory of Marine Ecology and Environmental sciences, Institute of Oceanology, {2. Academy of sciences, Qingdao 2.6071, china 3. College of Earth Science, graduate {12. of {2. Academy of sciences, Beijing 100049, china Institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China College of Earth Science Graduate University of Chinese Academy of Sciences Beijing 100049 China Key Laboratory of Marine Ecology and Environmental sciences Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China

Based on the data from 117 holes (9151 samples) and the research on ecology and palaeoecology of Foraminifera combined with that on Ostracoda, diatoms, pollen and spores, eight marine transgressions have been recognized in the great plain regions through the Quaternary sequences and two marine transgressions have been found since the Late Pleistocene in the coastal plain (bedrock coast) areas. In the North china Plain, these are in ascending order:the Bohai transgression in the Early Pleistocene, the Haixing and Huanghua transgressions in the Middle Pleistocene, the Baiyangdian and Cangzhou transgressions in the Late Pleistocene, and the Tianjin transgression in the Holocene. In the Yangtze River Delta region the Rugao and Zhoupu transgressions occurred in the Early Pleistocene, the Shanghai, Jiading, and Wangdian transgressions in the Middle Pleistocene, the Jiangyin and Ge Hu transgressions in the Late Pleistocene, and the Zhenjiang transgression in the Holocene. In the coastal plain (bedrock coast) areas of North china, the Cangzhou transgression was recorded in the Late Pleistocene and the Tianjin transgression in the Holocene, whereas in South china the Fuzhou transgression took place in the Late Pleistocene and the Changle transgression in the Holocene. The transgressions correspond to warm periods and regressions to cold periods. The younger transgressions were not only of shorter duration, but also of larger magnitude. These findings point to the existence of four flood event strata since the Middle Pleistocene: two in the late Middle Pleistocene and another two in the Late Pleistocene.

关键词： Quaternary marine transgressions palaeoclimate eastern china

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Compression behavior of Zr_(41)Ti_(14)Cu_(12.5)Ni_(10)Be_(2..5) bulk metallic glass up to 2. GPa

引用

Science china(Physics,Mechanics & Astronomy) 2005年第3期48卷 319-324页

作者： LI Gong 1, 2., ZHAN Zaiji 2., LIU Jing 3., YUN Jinku 1 , SUN Liling 2., LIU Riping 1 , ZHANG Jun 2.& WANG Wenkui 1, 2.1. Key Laboratory of Metastable Materials Science and Technology, Yanshan university, Qinhuangdao 066004,{2. 2. Center for Condensed Matter Physics, Institute of Physics, chinese Academy of {3., Beijing 100080,{2. 3. BSRF, Institute of High Energy Physics, chinese Academy of {3., Beijing 10003.,{2. Key Laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao China Center for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing China BSRF Institute of High Energy Physics Chinese Academy of Sciences Beijing China

The compression of a Zr41Ti14Cu12.5Ni10Be2..5 bulk metallic glass (BMG) is investigated at room temperature up to 2. GPa using in-situ high pressure energy dispersive X-ray diffraction with a synchrotron radiation source. The pressure-induced structural relaxation is exhibited. It is found that below about 8 GPa, the existence of excess free volume contributes to the rapid structural relaxation, which gives rise to the rapid volumetric change, and the structural relaxation results in the structural stiffness under higher pressure.

关键词： bulk metallic glass, high pressure, structural relaxation, synchrotron radiation.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Application of the moist vorticity vector in the analysis of a heavy rainfall event in North china

引用

Progress in Natural Science:Materials International 2007年第12期17卷 1457-1465页

作者： Zhao Yu1,2.3. Wang Jianguo4 and Xue Deqiang2.1. Laboratory of Cloud-Precipitation Physics and Severe Storms, Institute of Atmospheric Physics, chinese Academy of {2., Beijing 10002., china 2. Shandong Provincial Meteorological Observatory, Jinan 2.003., china 3. graduate university of chinese Academy of {2., Beijing 10003., china 4. Shandong Provincial Meteorological Bureau, Jinan 2.003., china) Laboratory of Cloud-Precipitation Physics and Severe Storms Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Shandong Provincial Meteorological Observatory Jinan 250031 China graduate university of {2. Academy of {3. Beijing 100039 China Shandong Provincial Meteorological Bureau Jinan 250031 China

The moist vorticity vector (MVV), defined as (ζa×▽qv)/ρ introduced by Gao et al. is used to study a heavy rainfall event in North china. The MVV has zonal, meridional and vertical components in a three-dimensional framework. Analysis of domain-mean and mass-integrated quantities shows that the variation of the vertical component of the MVV closely follows the variation of the cloud hydrometeors, with a linear correlation coefficient of 0.95, indicating that the vertical component of the MVV is strongly associated with midlatitude convection. Further analysis shows that the vertical component of the MVV reflects the interaction between the horizontal vorticity and the horizontal specific humidity gradient, which can associate dynamic and thermodynamic processes with cloud microphysical processes. Thus, this study can help to understand how the interaction between circulations and clouds aids the development of convection, and the MVV can be used to trace the development and evolution of heavy rainfall.

关键词： moist vorticity vector heavy rainfall modeling study.

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

fMRI time series analysis based on stationary wavelet and spectrum analysis

引用

Progress in Natural Science:Materials International 2006年第11期16卷 1171-1176页

作者： ZHI Lianhe~ 1,2.3., ZHAO Xia~4, SHAN Baoci~1**, PENG Silong~5, YAN Qiang~1, YUAN Xiuli~1 and TANG Xiaowei~ 1,6 (1. Key Laboratory of Nuclear Analysis Techniques, Institute of High Energy Physics, chinese Academy of {2., Beijing 100049,{3. 2. graduate School of chinese Academy of {2., Beijing 100049,{3. 3. Department of Physics, Zhoukou Normal university, Zhoukou 466100,{3. 4. Research Imaging Center, university of Texas Health Science Center, San Antonio, Texas 782.9, USA 5. National ASIC Design and Engineering Center, Institute of Automation, chinese Academy of {2., Beijing 100049,{3. 6. Department of Physics, Zhejiang university, Hangzhou 3.002.,{3.) Key Laboratory of Nuclear Analysis Techniques Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China

The low signal to noise ratio (SNR) of functional MRI (fMRI) prefers more sensitive data analysis methods. Based on stationary wavelet transform and spectrum analysis, a new method with high detective sensitivity was developed for analyzing fMRI time series, which does not require any prior assumption of the characteristics of noises. In the proposed method, every component of fMRI time series in the different time-frequency scales of stationary wavelet transform was discerned by the spectrum analysis, then the components from noises were removed using the stationary wavelet transform, finally the components of real brain activation were detected by cross-correlation analysis. The results obtained from both simulated and in vivo visual experiments illustrated that the proposed method has much higher sensitivity than the traditional cross-correlation method.

关键词： fMRI stationary wavelet transform spectrum analysis data analysis.

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Exsolution of ilmenite and Cr-Ti magnetite from olivine of garnet-wehrlite

引用

Science china Earth sciences 2005年第9期48卷 1368-1376页

作者： LIU Xiangwen1,2. JIN Zhenmin1,3. QU Jing2.& WANG Lu2.1. State Key Laboratory of Geological Processes and Mineral Resources, china {2. of Geosciences, Wuhan 43.074, china 2. graduate School of china {2. of Geosciences, Wuhan 43.074, china 3. Faculty of Earth sciences, china {2. of Geosciences, Wuhan 43.074, china State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Wuhan China graduate School of china {2. of Geo{3. Wuhan China Faculty of Earth sciences China University of Geosciences Wuhan China

Exsolution of rod-like ilmenite (Ilm) and Cr-Ti magnetite (Mt) have been found in olivine of garnet-wehrlite from the core of chinese Continental sciences Drilling (CCSD). Their composition, morphology, crystal structure and their topotaxies with host olivine have been studied in detail by the transmission electron microscopy (TEM) and electron probe microanaly- sis (EPMA) technique. It shows that rod-like Ilm exsolution reported in this paper has similar characteristic with that of Alpe Arami olivine, while Cr-Ti magnetite exsolution mentioned in this paper has large discrepancy with chromite exsolution in Alpe Arami olivine. These observations suggest that both of the exsolutions found in this paper should be solid solution phases in β-olivine at their first period, then experiencing decomposition of solid solution and therefore forming Ilm and Cr-Ti magnetite exsolution with the pressure decreasing. So, this garnet-wehrlite perhaps had been ever located in mantle transition zone with a minimum depth of {2.0 km.

关键词： garnet-wehrlite, ilmenite, magnetite, exsolution, CCSD.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The solid lubricating material experiment device for Shenzhou-7 Spaceship

引用

Science china(Technological sciences) 2010年第9期53卷 2521-2527页

作者： WANG Ke1,2.REN WeiJia1,WANG ShiDa1 & WENG LiJun3.1 Academy of Opto-Electronics,chinese Academy of {2.,Beijing 100190,china 2.{3. university of chinese Academy of {2.,Beijing 100049,china 3.Lanzhou Institute of Chemical Physics,chinese Academy of {2.,Lanzhou 73.000,china Academy of Opto-Electronics Chinese Academy of Sciences graduate university of {2. Academy of {3.

A solid lubricating material exposure experiment in space is one of the missions during the seventh manned spaceflight of china,and the key is to develop a device which can be fixed reliably outside of the orbital module and can be fetched conveniently by an astronaut during space *** solid lubricating material experiment device needs to be locked reliably in a vibrating and impacting environment during the launch phase,and should meet the requirement that it can be unlocked and fetched reliably by the astronaut wearing an extravehicular spacesuit via simple operations in orbit in an environment of high and low *** for the device we developed,the environmental characteristic of the mission was analyzed,the mechanical analysis and thermal analysis were carried out,and then a mechanism with functions of mechanical locking,structural self-locking and manual unlocking was *** device was verified by a sequence of experiments and was fetched by the astronaut during the flight of the Shenzhou-7 Spaceship.

关键词： manned spaceflight exposure experiment mechanism unlock

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Congruences on ideal nil-extension of completely regular semigroups

引用

chinese Science Bulletin 1998年第5期43卷 379-381页

作者： REN Xueming 1, 2.GUO Yuqi 2.and CEN Jiaping (Shum Kar-ping) 3.. Department of Mathematics, Xi’an university of Architecture & Technology, Xi’an 710055,{2. 2. Department of Mathematics, Yunnan university, Kunming 650091,{2. 3. Department of Department of Mathematics Xi’an University of Architecture & Technology Xi’an China Department of Mathematics Yunnan University Kunming China Department of Mathematics Chinese University of Hong Kong Hong Kong

Let S be an ideal nil-extension of a completely regular semigroup K by a nil semigroup Q with zero. A concept of admissible congruence pairs (δ,ω) of S is introduced, where δ and ω are a congruence on Q and a congruence on K respectively. It is proved that every congruence on S can be uniquely respresented by an admissible congruence pair (δ,ω) of S. Suppose that ρ K denotes the Rees congruence induced by the ideal K of S. Then it is shown that for any congruence σ on S,a mapping Γ:σ|→(σ Q,σ K) is an order-preserving bijection from the set of all congruences on S onto the set of all admissible congruence pairs of S,where σ K is the restriction of σ to K and σ Q=(σ∨ρ K)/ρ K. Moreover,the lattice of congruences of S is also discussed. As a special case,every congruence on completely Archimedean semigroups S is described by an admissible quarterple of S. The following question is asked: Is the lattice of congruences of the completely Archimedean semigroup a semimodular lattice?

关键词： completely regular semigroups ideal nil-extension congruences.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A puzzle of the radio-quiet quasar PG 1407+2.5:Are optical and X-ray emissions produced from a relativistic jet?

引用

Science china(Physics,Mechanics & Astronomy) 2011年第1期54卷 183-186页

作者： CHEN Liang 1,2.3.& BAI JinMing 1,2.1 National Astronomical Observatories/Yunnan Observatory,chinese Academy of {2.,Kunming 650011,china 2.Key Laboratory for the Structure and Evolution of Celestial Objects,chinese Academy of {2.,Kunming 650011,china 3.graduate university of chinese Academy of {2.,Beijing {12.,china chinese Academy of sciences National Astronomical Observatories/Yunnan Observatory Kunming China (GRID:grid.9227.e) (ISNI:***) chinese Academy of sciences Key Laboratory for the Structure and Evolution of Celestial Objects Kunming China (GRID:grid.9227.e) (ISNI:***) graduate university of {2. Academy of {3. Beijing China (GRID:grid.458514.9) chinese Academy of sciences National Astronomical Observatories/Yunnan Observatory Kunming China (GRID:grid.9227.e) (ISNI:***) chinese Academy of sciences Key Laboratory for the Structure and Evolution of Celestial Objects Kunming China (GRID:grid.9227.e) (ISNI:***)

PG 1407+2.5 is a radio quiet quasar that has a relativistic *** this report,we show some peculiar properties of its optical and X-ray emissions,which indicate possible non-thermal origins produced from the *** use a simple synchrotron + synchrotron self Compton (SSC) model to fit the emissions with different ratios of energy densities between the magnetic field and electrons (η≡U B/U e),which predicts a different γ-ray *** First LAT AGN Catalog (1LAC) did not include PG 1407+2.5,which indicates an upper limit of γ-ray *** upper limit constrains the ratio to be unreasonably large (η≥10 4-5).This inversely indicates that the optical and X-ray emissions may not be produced from the beaming *** discuss the physical implications of these results.

关键词： active galactic nuclei jet non-thermal emission PG 1407+2.5

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：