检索结果-南通市图书馆

A new method to prepare clean cuticular membrane from fossil leaves with thin and fragile cuticles

Science China Earth sciences 2011年第2期54卷 223-227页

作者： wang Li1,2 & LENG Qin1,3 1 State Key Laboratory of palaeobiology and Stratigraphy,Nanjing Institute of Geology and palaeontology,chinese academy of sciences,Nanjing 210008,China 2 graduate School of chinese academy of sciences,Beijing 100049,China 3 Department of Science and Technology,Bryant university,Smithfield RI 02917,USA State Key Laboratory of palaeobiology and Stratigraphy Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing China graduate School of chinese academy of sciences Beijing China Department of Science and Technology Bryant University Smithfield USA

Leaf cuticle analysis has long been a powerful tool for fossil plant identification, systematics, and palaeoclimatological recon- struction. In recent decades the application of stomatal frequency data that are relied on precise calculation of stomata on plant fossil cuticles to reconstruct ancient atmospheric Co2 concentration made the preparation of cuticular membrane with sufficient size a critical technique in palaeoclimatological research. However, for plants with originally thin and fragile cuticles, e.g., most deciduous plants, conventional techniques sometimes fail to obtain cuticular membranes with sufficient size, or sometimes unable to recover any. This has largely hampered the usage of fossil cuticle analysis in palaeobotanical and palaeo- climatological research. Here, we describe a new method using clear nail polish as a medium to ＂strengthen＂ the originally thin and fragile cuticles prior to maceration p.o.edures. We demonstrate the method by using middle Eocene Metasequoia fossils that were notorious for the difficulty of recovering large-sized clean cuticular membranes due to their thin and fragile nature. Metasequoia, with well-documented and widely-distributed fossil records since the Late Cretaceous and with a living repre- sentative, 114. glyp.o.troboides, as a comparative reference, bas been widely used as a model genus for the study of evolution of plants, palaeoclimatological reconstruction, and plant adaptation to climate changes. But its deciduous habit p.o.uces thin cuticles and makes the preparation of clean cuticular membranes a tedious p.o.ess. The new method successfully allows us to recover its delicate cuticular membranes with sufficient sizes for SEM observation and stomatal frequency analysis.

关键词： fossil leaf cuticle Metasequoia new method thin and fragile cuticle SEM observation stomatal frequency Co2

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

Birthrates and delay times of Type Ia supernovae

引用

Science China(physics,Mechanics & Astronomy) 2010年第3期53卷 586-590页

作者： wang Bo1,2,3, LIU ZhengWei1,2,3, HAN YunKun1,2,3, LEI ZhenXin1,2,3, LUo Yangping1,2,3 & HAN ZhanWen1,2 1National Astronomical observatories/Yunnan observatory, chinese academy of sciences, Kunming 650011, China 2Key Laboratory for the Structure and Evolution of Celestial objects, chinese academy of sciences, Kunming 650011, China 3graduate university of chinese academy of sciences, Beijing 100049, China National Astronomical observatories/Yunnan observatory Chinese Academy of Sciences Kunming China Key Laboratory for the Structure and Evolution of Celestial objects Chinese Academy of Sciences Kunming China graduate university of chinese academy of sciences Beijing China

Type Ia supernovae (SNe Ia) play an important role in diverse areas of astrophysics, from the chemical evolution of galaxies to observational cosmology. However, the nature of the p.o.enitors of SNe Ia is still unclear. In this paper, according to a detailed binary population synthesis study, we obtained SN Ia birthrates and delay times from different p.o.enitor models, and compared them with observations. We find that the Galactic SN Ia birthrate from the double-degenerate (DD) model is close to those inferred from observations, while the birthrate from the single-degenerate (SD) model accounts for only about 1/2-2/3 of the observations. If a single starburst is assumed, the distribution of the delay times of SNe Ia from the SD model is a weak bimodality, where the WD + He channel contributes to the SNe Ia with delay times shorter than 100 Myr, and the WD + MS and WD + RG channels to those with age longer than 1 Gyr.

关键词： binaries: close stars: evolution supernovae: general white dwarfs

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

Zircon SHRIMp U-pb geochronology and petrogenesis of the plagiogranites from the Lagkor Lake ophiolite,Gerze,Tibet,China

引用

chinese Science Bulletin 2007年第5期52卷 651-659页

作者： ZHANG YuXiu1,2, ZHANG KaiJun1,3, LI Bing1,2, wang Yang1,2, WEI QingGuo1,2 & TANG XianChun1,2 1 Key Laboratory of Marginal Sea Geology, Guangzhou Institute of Geochemistry, chinese academy of sciences, Guangzhou 510640, China 2 graduate university, chinese academy of sciences, Beijing 100039, China 3 Department of Earth sciences, Nanjing university, Nanjing 210093, China Key Laboratory of Marginal Sea Geology Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China graduate university Chinese Academy of Sciences Beijing China Department of Earth sciences Nanjing University Nanjing China

地关系与 petrographical 一起， petrological ，和 geochemicalcharacteristics ，和锆石人口，显示从在 Bangong-Nujiang 缝术地区的 Lagkor Lakeophiolite 的 plagiogranites (～ Gerze 县的 20 km 南方，中央西藏，中国)，由在海洋的外壳的运输期间的可锻的砍源于含水的斑粝岩的 anatexis 。因此，这种 plagiogranite 比传播海洋的外壳晚对或很少同时代。锆石虾 166 ±使 2.5 妈变老因为 plagiogranites 显示海洋的盆在中间的侏罗记在 Bangong-Nujiang 地区的西方的部分存在。

关键词：西藏改则县拉果错湖泊蛇绿岩斜长花岗岩锆SHRIMp U-pb地质年代岩石成因

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

LEAFY HEAD2,which encodes a putative RNA-binding p.o.ein,regulates shoot development of rice

引用

Cell Research 2006年第3期16卷 267-276页

作者： Guo Sheng Xiong~(1,3) Xing Ming Hu~2 Yong Qing Jiao~1 Yan Chun Yu~1 Cheng Cai Chu~1 Jia Yang Li~1 Qian Qian~2 Yong Hong wang~11 State Key Laboratory of plant Genomics and National Center for plant Gene Research,Institute of Genetics and Developmental Biology,chinese academy of sciences,Beijing 100101,China 2 State Key Laboratory of Rice Biology,China National Rice Research Institute,chinese academy of Agricultural sciences,Hangzhou 310006,China 3 graduate university of chinese academy of sciences,Beijing 100049,China State Key Laboratory of plant Genomics and National Center for plant Gene Research Institute of Genetics and Developmental Biology Chinese Academy of Sciences Beijing China graduate university of chinese academy of sciences Beijing China State Key Laboratory of Rice Biology China National Rice Research Institute Chinese Academy of Agricultural Sciences Hangzhou China

During vegetative development,higher plants continuously form new leaves in regular spatial and temporal *** with abnormal leaf developmental patterns not only p.o.ide a great insight into understanding the regulatorymechanism of plant architecture,but also enrich the ways to its modification by which crop yield could be ***,we reported the characterization of the rice leafy-head2 (lhd2) mutant that exhibits shortened plastochron,dwarfism,reduced tiller number,and failure of phase transition from vegetative to rep.o.uctive *** and histologicalstudy revealed that the rapid emergence of leaves in lhd2 was resulted from the rapid initiation ofleafprimordia whereasthe reduced tiller number was a consequence of the suppression of the tiller bud *** molecular and geneticanalysis showed that LHD2 encodes a putative RNA binding p.o.ein with 67% similarity to maize *** ofgenome-scale expression p.o.iles between wild-type and lhd2 plants suggested that LHD2 may regulate rice shoot devel-opment through KNoXand hormone-related *** similar phenotypes caused by LHD2 mutation and the conservedexpression pattern of LHD2 indicated a conserved mechanism in controlling the temporal leaf initiation in grass.

关键词： phyllotaxy plastochron LHD2 RNA-binding p.o.ein stem elongation plant architecture oryza sativa L

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

Validation of three infiltration models on purple soil under simulated rainfall

引用

p.o.ress in Natural Science:Materials International 2007年第9期17卷 1059-1066页

作者： wang Yukuan1,2,Fu Bin1,3,Xu pei1,2,wang Daojie1,2,wang Xiantuo1,3 and wang Yongqiang1,3(1.Key Laboratory of Mountain Surface p.o.ess and Hazards,chinese academy of Seiences,Chengdu 610041,China 2.Institute of Mountain Hazards and Environment,chinese academy of sciences,Chengdu 610041,China 3.graduate university of the chinese academy of sciences,Beijing 100049,China) Key Laboratory of Mountain Surface p.o.ess and Hazards Chinese Academy of Sciences Chengdu 610041 China Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China graduate university of the chinese academy of sciences Beijing 100049 China

So as to find models suitable for the prediction of water infiltration in purple soil,infiltration rates simulated by three popular empirical infiltration models,Horton model,Kostiakov model,and the modified Kostiakov model,were compared by using those observed results on slope in purple soil under rainfall simulation.28 sets of infiltration data were divided into two parts for parameter estimation and validation *** performance of the three infiltration models was evaluated with the Nash and Sutcliffe efficiency *** results show that the percent for Nash and Sutcliffe efficiency greater than 0.7 is about 69.7% for the Horton model,and 48.48%,and 54.55% for the Kostiakov model and the modified Kostiakov model,*** model is better than Kostiakov model and the modified Kostiakov model in most rain events in the ***,Kostiakov model is still suitable for reasonable prediction of the infiltration in purple soil sloping farmland because fewer parameters are ***,rainfall intensity has significant effects on the parameter values used in the simulation *** simulation results can be imp.o.ed by choosing suitable parameters according to the rainfall intensity.

关键词： infiltration model sloping farmland purple soil rainfall simulation

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

An efficient chiral synthesis of (R)-N-[3-acetyl-4-(2-hydroxy-3-isop.o.ylamino-p.o.oxy)phenyl]-butanamide with high enantioselectivity

引用

Science China Chemistry 2009年第8期52卷 1216-1219页

作者： wang NaiXing1,2 & TANG XinLiang1,3 1 Technical Institute of physics and Chemistry,chinese academy of sciences,Beijing 100080,China 2 College of Chemistry and Chemical Engineering,graduate university of chinese academy of sciences,Beijing 100049,China 3 School of Chemical Engineering and Environment,Beijing Institute of Technology,Beijing 100081,China Technical Institute of physics and Chemistry Chinese Academy of Sciences Beijing China College of Chemistry and Chemical Engineering Graduate University of Chinese Academy of Sciences Beijing China School of Chemical Engineering and Environment Beijing Institute of Technology Beijing China

R-Enantiomer of the β-recep.o. antagonist N-[3-acetyl-4-(2-hydroxy-3-isop.o.ylamino-p.o.oxy)phenyl] butanamide with high enantioselectivity was synthesized from cheap starting materials and enantiopure chiral reagent through an efficient,convenient and practical synthetic *** p.o.uct was detected by 1H NMR,13C NMR,and MS,and the enatiomeric excess was determined by chiral HpLC analysis using a chiracel AD-H column.

关键词： chiral synthesis enantioselectivity enatiomeric excess chiral HpLC analysis

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

origin of the Red Earth sequence on the northeastern Tibetan plateau and its implications for regional aridity since the middle Miocene

引用

Science China Earth sciences 2006年第5期49卷 505-517页

作者： wang Xianyan1,7, LU Huayu1,2, JI Junfeg3, wang Xiaoyong1,7, ZHAo Jingbo4, HUANG Baochun5 & LI Zhen6 1. SKLLQG, Institute of Earth Environment, chinese academy of sciences, Xi’an 710075, China 2. Department of Urban and Resources sciences, Nanjing university, Nanjing 210093, China 3. Department of Earth sciences, Nanjing university, Nanjing 210093, China 4. Department of Geography, Shaanxi Normal university, Xi’an 710062, China 5. Institute of Geology and Geophysics, chinese academy of sciences, Beijing 100029, China 6 Department of Geography, Qinghai Normal university, Xining 810008, China 7. graduate School of the chinese academy of sciences, Beijing 100039, China SKLLQG Institute of Earth Environment Chinese Academy of Sciences Xi’an China graduate School of the chinese academy of sciences Beijing China Department of Urban and Resources sciences Nanjing University Nanjing China Department of Earth sciences Nanjing University Nanjing China Department of Geography Shaanxi Normal University Xi’an China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China Department of Geography Qinghai Normal University Xining China

The Red Earth deposit around Xining, northeastern Tibetan plateau, has beenstudied in terms of soil micro-structure, grain-size distribution, major- and trace-elementchemistry and magne-tostratigraphy. Field investigations indicate that the Red Earth sequenceconsists of 25 visually definable yellow-brown and weakly-developed soils interbedded with reddishstrongly-developed soils, and has a similar structure to the aeolian Red Clay deposit on the chineseLoess plateau. Grain-size analysis shows that the Red Earth deposit is very fine-grained with anegligible sand fraction ( > 63 μm). Thin-section observations under light microscopy show that thedeposit has a clayey texture and the coarse fraction ( > 10 μm) mainly consists of quartz,feldspar and micas. pyroxene and hornblende were also observed. This mineralogical composition ofthe coarse fraction is similar to that of the Quaternary loess. In addition, all of the mineralgrains are semi angular semi-angular and are generally finer than 63 μm. There is a good agreementbetween the major and minor trace element chemistry of loess-soil units and the Red Earth *** REE distributions of the loess-soil and the Red Earth deposit are similar in shape, withenriched LREE and fairly flat HREE p.o.iles and a clear negative Eu anomaly. The geochemicalcharacteristics of the Red Earth deposit are also identical to those of upper continental crust,thus indicating a wind-blown origin. Magnetostratigraphic investigation shows that onset of the RedEarth deposition predates 11.4 Ma Bp (13.6 Ma at a nearby site). The distribution of the reportedMiocene aeolian loess at Qin''an of the Loess plateau is still unknown. our results indicate thatthis aeolian deposit had extended to the northeastern Tibetan plateau by at least the middleMiocene. The similarity of the element geochemistry between the Red Earth deposit and the overlyingloess shows that they may have similar sources and dynamic transport system, and may indicate thatthe

关键词： Red Earth deposit, Northeastern Tibetan plateau, aeolian deposit, aridity of Asia, the middle Miocene.

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

^(137)Cs Redistribution in Thin Stony Soil of a Carbonate Rock Slope in Southwest China

引用

pedosphere 2011年第1期21卷 37-45页

作者： LI Hao ZHANG Xin-Bao wang Kc-Lin WEN An-Bang Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 (China) graduate university Chinese Academy of Sciences Beijing 100049 (China) State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 (China) Institute of Subtropical Agriculture Chinese Academy of Sciences Changsha 410125 (China)

The fallout radionuclide cesium-137(137 Cs) has been widely emp.o.ed as a tracer for assessment of soil loss from thick uniform soils;however,few studies have been conducted on thin stony soils on slopes underlain by carbonate rocks which are widely distributed in karst *** derived from 137 Cs measurement of soil samples collected along a carbonate rock slope with thin stony soil where neither soil erosion nor deposition occurred was used to investigate the characteristics of 137 Cs redistribution in a karst area of Southwest *** results indicated that the 137 Cs inventories of the surface soil on the slope studied were much lower than that of the local 137 Cs reference inventory and the 137 Cs activities were much higher than those on slopes with thick uniform *** spatial distribution of 137 Cs inventories was characterized by considerable *** high 137 Cs depletion in the stony soil of the slope studied was mainly because a considerable p.o.ortion of the fallout input of 137 Cs could be lost with runoff and the dissolution of carbonate particles in the soil p.o.oted the loss of 137 *** demonstrated that the rates of soil loss could not be estimated from the degree of depletion of the 137 Cs inventory relative to the local reference inventory for the thin stony soil of the rocky slope underlain by carbonate rocks in the study area in the way that has been widely used in areas with thick uniform soils.

关键词： carbonate dissolution, ^137Cs fallout, ^137Cs inventory karst area runoff

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

Enrichment of heavy metal elements and their adsorption on iron oxides during carbonate rock weathering p.o.ess

引用

p.o.ress in Natural Science:Materials International 2009年第9期19卷 1133-1139页

作者： Shanqin Ni a, Yiwen Jua, Quanlin Hou a,*, Shijie wang b, Qing Liua, Yudong Wua, Lingling Xiao a a College of Earth Science, graduate university of chinese academy of sciences, Beijing 100049, China b State Key Laboratory of Environment Geochemistry, Institute of Geochemistry, chinese academy of sciences, Guiyang 550002, China College of Earth Science Graduate University of Chinese Academy of Sciences Beijing 100049 China State Key Laboratory of Environment Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

Analysis of trace elements in the Lower palaeozoic carbonate rock strata of the Beijing area shows that the Cr, Zn, Cd and pb contents increase from primary carbonate rocks to weathered carbonate rocks and from primary carbonate rocks to the soil coexisting with carbonate rock. Distributions of Cr, Zn, Cd and pb have the same trends as that of Fe2o3. Iron oxides play different roles at different stages of weathering of carbonate rock. The adsorption of Cr, Zn, Cd and pb on Fe2o3 is greater than on Feo in soil. However, Feo, as a main component of clay mineral, is a better adsorbent of Cr, Zn, Cd and pb than Fe2o3 in weathered and primary carbonate rocks. According to R-type clustering analysis, the main components of carbonate rock are divided into marine and continental sediments. Correlation analysis shows that heavy metal elements mainly exist in continental substances.

关键词： Carbonate rock Heavy metal elements Adsorbent Enrichment

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

Mapping forest fire risk zones with spatial data and principal component analysis

引用

Science China(Technological sciences) 2006年第Z1期49卷 140-149页

作者： XU Dong, Guofan Shao, DAI Limin, HAo Zhanqing, TANG Lei & wang Hui Institute of Applied Ecology, chinese academy of sciences, Shenyang 110016, China graduate university of chinese academy of sciences, Beijing 100039, China Department of Forestry and Natural Resources, purdue university, West Lafayette, IN 47907, USA Department of Management, Shenyang Institute of Aeronautical Engineering, Shenyang 110034, China Department of City Development, Jinan university, Jinan 250002, China Institute of Applied Ecology Chinese Academy of Sciences Shenyang China graduate university of chinese academy of sciences Beijing China Department of Forestry and Natural Resources Purdue University West Lafayette USA Department of Management Shenyang Institute of Aeronautical Engineering Shenyang China Department of City Development Jinan University Jinan China

By integrating forest inventory data with remotely sensed data, new data layers for factors that affect forest fire potentials were generated for Baihe Forestry Bureau in Jilin p.o.ince of China. The principle component analysis was used to sort out the relationships between forest fire potentials and environmental factors. The classifications of these factors were performed with GIS, generating three maps: a fuel-based fire risk map, a topography-based fire risk map, and an anthropogenic-factor fire risk map. These three maps were then synthesized to generate the final fire risk map. The linear regression method was used to analyze the relationship between an area-weighted value of forest fire risks and the frequency of historical forest fires at each forest farm. The results showed that the most important factor contributing to forest fire ignition was topography, followed by anthropogenic factors.

关键词： wildfire risk, regression analysis, geographic information system, remote sensing, Baihe Forestry Bureau.

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：