检索结果-南通市图书馆

Synthesis,characterization,structures and magnetic property of chiral oxalate-bridged dicopper(Ⅱ) complexes

Science china Chemistry 2010年第6期53卷 1255-1260页

作者： WU Ling1,WANG Jun2,ZHU CaiFei1,LIN YiJi1,CHEN LeiQi1,FAN Jun2 & ZHANG Hui1 1State key laboratory of Physical Chemistry of Solid Surfaces Department of Chemistry,College of Chemistry and Chemical Engineering,Xiamen University,Xiamen 361005,china 2School of Chemistry and environment,South china Normal University,Guangzhou 510006,china 1. State key laboratory of Physical Chemistry of Solid Surfaces Department of Chemistry College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China2. School of Chemistry and Environment South China Normal University Guangzhou 510006 China

The oxalato-bridged dicopper(II) complexes [Cu2(μ-ox)(LRR)2(H2O)2(ClO4)2] (1),[Cu2(μ-ox)(LRR)2(CH3COCH3)2(ClO4)2](1a),[Cu2(μ-ox)(LSS)2(H2O)2(ClO4)2] (2) and [Cu2(μ-ox)(LRR)(LSS)2(CH3COCH3)2(ClO4)2] (3) [LRR = (8R,10R)-(-)-[4,5]-pineno2,2′-bipyridine,LSS = (8S,10S)-(+)-[4,5]-pineno-2,2′-bipyridine;ox2= oxalate] were first prepared.A possible mechanism for the formation of the chial dicopper(II) complexes was *** on elemental analysis,conductance measurement,UV-Vis spectra,CD spectra and X-ray single-crystal diffraction,the oxalato-bridged structures of 1 and 2 were deduced to adopt two Cu(II) ions and the bridged oxalate lying in the nearly same *** crystal structures of 1a and 3 reveal that the coordination geometry around each Cu(II) ion is an elongated and distorted octahedron and two axial solvent molecules and two perchlorate ions are anti to each other respectively in both binuclear *** solution CD spectra of 1 and 2 in the visible d-d range show very weak Cotton effects with peaks at 588 and 779 nm,which are approximately of mirror image,suggesting the optical activities may be derived from the vicinal effects of the chiragenic centers at the pinene group of LRR and LSS,*** 1 has been characterized by variable-temperature magnetic susceptibility and the data was least-square fitted to the Blenaey-Bowers *** exchange integral J was found to be -338.41(4) cm-1,indicating a strong antiferromagnetic interaction between two copper(II) ions.

关键词： dicopper(II) complex chiral bipyridine μ-oxalate bridge crystal structure CD spectroscopy magnetic property

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

High-resolution dating of Co-rich crusts: A comparative study using the methods of orbital pacing and ^(230)Th_(ex)/^(232)Th dating

引用

Science china Earth Sciences 2009年第4期52卷 484-488页

作者： HAN XiQiu1,2, QIU ZhongYan1,2,3, MA WeiLin1,2 & QIAN JiangChu1,2 1 key laboratory of Submarine Geosciences, State Oceanic Administration, Hangzhou 310012, china 2 Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, china 3 Department of Earth Sciences, Zhejiang University, Hangzhou 310027, china key laboratory of Submarine Geosciences State Oceanic Administration Hangzhou 310012 China Second Institute of Oceanography State Oceanic Administration Hangzhou 310012 China Department of Earth Sciences Zhejiang University Hangzhou

Due to their slow growth rates, seamount Co-rich crusts are very difficult to date with high resolution and precision. This paper is to test the use of orbital pacing on the growth profile of crusts to determine high-resolution age and growth rate. Crust CB14 from the central Pacific Ocean was selected for this study. We first examined the growth pattern in detail under a reflected-light microscope and ascertained that the growth environment was stable for the sub-layer 1 (0-3 mm). We then used electron micro-probe line-scanning to obtain elemental profiles. The pattern of the power spectrum analysis of the Al-profile revealed that there are significant cycles of 113.9, 87.8, 51.5, 42.2 and 25.8 μm. These cycles correspond to the Milankovitch cycles of 53.1, 41, 24, 19.7 and 12 ka, respectively, and yield the growth rate of about 2.14 mm/Ma and an age of about 1.40 Ma for the boundary between the sub-layer 1 and sub-layer 2. We also used a drilling machine with a numerically controlled drive to obtain high-resolution samples at 0.1mm intervals, and used the 230Thex/232Th method to date the samples. For the uppermost 1.3 mm, the growth rate was about 2.15 mm/Ma, and the age for the layer at the depth of 3 mm was about 1.40 Ma, which coincides perfectly with the results obtained from orbital pacing. Thus, it is considered that orbital pacing is a new and effective method to determine the growth rate of the seamount Co-rich crust. This method is applicable for establishing a high-resolution age frame for the crusts of the world's oceans.

关键词： seamount Co-rich crust Milankovitch cycles 230Thex/232Th dating growth rates of Mn-crusts central Pacific Ocean

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

Biodegradation of polycyclic aromatic hydrocarbons in sediments from the Daliao River watershed, china

引用

Journal of environmental Sciences 2009年第7期21卷 865-871页

作者： QUAN Xiangchun, TANG Qian, HE Mengchang, YANG Zhifeng, LIN Chunye, GUO Wei State key Joint laboratory of environmental Simulation and Pollution Control, School of environment, Beijing Normal University, Beijing 100875, china. [a]State key Joint laboratory of environmental Simulation and Pollution Control School of Environment Beijing Normal University Beijing 100875 China

The Daliao River, as an important water system in Northeast china, was reported to be heavily polluted by polycyclic aromatic hydrocarbons （PAHs）. Aerobic biodegradations of four selected PAHs （naphthalene, phenanthrene, fluorene and anthracene） alone or in their mixture in river sediments from the Daliao River water systems were studied in microcosm systems. Effects of additional carbon source, inorganic nitrogen and phosphorus, temperature variation on PAHs degradation were also investigated. Results showed that the degradation of phenanthrene in water alone system was faster than that in water-sediment combined system. Degradation of phenanthrene in sediment was enhanced by adding yeast extract and ammonium, but retarded by adding sodium acetate and not significantly influenced by adding phosphate. Although PAHs could also be biodegraded in sediment under low temperature （5~C）, much lower degradation rate was observed. Sediments from the three main streams of the Daliao River water system （the Hun River, the Taizi River and the Daliao River） demonstrated different degradation capacities and patterns to four PAHs. Average removal rates （15 or 19 d） of naphthalene, phenanthrene, fluorene and anthracene by sediment were in the range of 0.062-0.087, 0.005-0.066, 0.008- 0.016 and 0-0.059 mg/（L.d）, respectively. As a result, naphthalene was most easily degraded compound, anthracene was the hardest one. In multiple PAHs systems, the interactions between PAHs influenced each PAH biodegradation.

关键词： biodegradation the Daliao River microcosm polycyclic aromatic hydrocarbon sediment

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

Responses of soil respiration in non-growing seasons to environmental factors in a maize agroecosystem,Northeast china

引用

Chinese Science Bulletin 2010年第24期55卷 2723-2730页

作者： LI RongPing1,2,3, ZHOU GuangSheng1,4 & WANG Yu1,3 1 State key laboratory of Vegetation and environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, china 2 Institute of Atmospheric environment, china Meteorological Administration, Shenyang 110016, china 3 Graduate University of Chinese Academy of Sciences, Beijing 100049, china 4 Chinese Academy of Meteorological Sciences, Beijing 100081, china State key laboratory of Vegetation and environmental Change Institute of Botany Chinese Academy of Sciences Beijing 100093 China Institute of Atmospheric environment China Meteorological Administration Shenyang 110016 China Graduate University of Chinese Academy of Sciences Beijing 100049 China Chinese Academy of Meteorological Sciences Beijing 100081 China

Based on continuous three-year measurements (from 2004 to 2007) of eddy covariance and related environmental factors, environmental controls on variation in soil respiration (Rs) during non-growing season were explored in a maize agroecosystem in Northeast china. Our results indicated that during non-growing seasons, daily Rs was 1.08-4.08 g CO2 m-2 d-1, and the lowest occurred in late November. The average Rs of non-growing season was 456.06 ± 20.01 g CO2 m-2, accounting for 11% of the gross primary production (GPP) of the growing season. Additionally, at monthly scale, the lowest value of Rs appeared in January or February. From the beginning to the end of non-growing season, daily Rs tended to decrease first, and then increase to the highest. There was a significant quadratic curve relationship between Rs and soil temperature at 10 cm depth when soil temperature was more than 0°C (Pchina.

关键词：中国东北地区农田生态系统生长季节土壤呼吸环境因素玉米土壤含水量反应

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

Sea-salt aerosol transport patterns over the Northern Hemisphere inferred from two subarctic ice core records

引用

Science china Earth Sciences 2005年第4期48卷 576-584页

作者： YAN Yuping1,2, KANG Shichang2,3,5, SUN Junying4,5, Paul A. Mayewski2 & QIN Dahe5 1. national Climate Center, china Meteorological Administration, Beijing 100081, china 2. Climate Change Institute, University of Maine, Orono, ME 04469, USA 3. Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, china 4. Chinese Academy of Meteorological Sciences, Beijing 100081, china 5. key laboratory of Ice Core and Cold Regions environment, Cold and Arid environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, china 1. national Climate Center China Meteorological Administration 100081 Beijing China 2. Climate Change Institute University of Maine 04469 Orono ME USA 3. Institute of Tibetan Plateau Research Chinese Academy of Sciences 100085 Beijing China 4. key laboratory of Ice Core and Cold Regions environment Cold and Arid Environmental and Engineering Research Institute Chinese Academy of Sciences 730000 Lanzhou China 5. Chinese Academy of Meteorological Sciences 100081 Beijing China

Atmospheric circulation reconstruction based on glaciochemical records requires knowledge of chemical concentration controls, such as source, transport pathway and strength. To gain insight into these processes, the relationships between glaciochemical records from two Northern Hemisphere sites (Mt. Logan in Yukon Territory and 20D in southern Greenland) and instrumental sea level pressure (SLP) series are investigated. Calibrations between Mt. Logan sea-salt sodium (ssNa+) concentration and SLP series show that ssNa+ concentrations are closely correlated with the autumntime (SON) Aleutian Low and the summertime (JJA) North Pacific Subtropical High. Both the deepened Aleutian Low and enhanced North Pacific Sub- tropical High strengthen the transport of sea-salt aerosols from the North Pacific to the Mt. Logan region. Calibrations between 20D ssNa+ concentrations and SLP series indicate that ssNa+ concentrations are closely related to the wintertime (Jan.) Icelandic Low. A deepening of the Icelandic Low strengthens winter storms and frequent cyclogenesis over the North Atlantic and pushes more sea-salt laden air masses to the Greenland ice sheet. Therefore, ice core ssNa+ records from the Mt. Logan region can be considered as a proxy for reconstructing the au- tumntime Aleutian Low and summertime North Pacific Subtropical High, and the ssNa+ records from Greenland ice core (20D) may provide a proxy for reconstructing the wintertime Icelandic Low.

关键词： sea-salt aerosol, ice core records, sea level pressure, subarctic regions.

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

Planation Surfaces on the Tibet Plateau,china

引用

Journal of Mountain Science 2008年第4期5卷 310-317页

作者： ZHANG Xinbao HE Xiubin WANG Yangchun LONG Yi Institute of Mountain Hazards and environment CAS Chengdu 610041 China State key laboratory of Loess and Quaternary Geology Institute of Earth Environment GAS Xi＇an 710075 China Graduate University of the Chinese Academic of Sciences Beijing 100039 China

A planation hypothesis is proposed to explain landform evolution of the Tibet Plateau. A denudation threshold （T）, the maximum potential denudation rate for a certain type of rock, is introduced to explain the combined effects of lithology and tectonics on landform evolution. If the tectonic uplifting rate （U） is equal to or less than the threshold rate （U ≤ T）, the tectonic uplifting and terrain denudation are in dynamic equilibrium, and landforms are in a steady state. The end product should be planation surfaces whether the original landforms are flat plains or deeply dissected mountains. If U 〉 T, uplift and denudation are not able to reach a dynamic equilibrium state. The plateau surface is mostly underlain by soft rocks, such as the Mesozoic epimetamorphic argillites and Tertiary sedimentary rocks, while the mountain ranges comprise hard rocks, such as granite, gneiss and limestone. In soft rock regions, hills are low with a relative relief of mostly less than 100 m and the slopes are gentle at a gradient of 〈200. In contrast, hills can maintain steep slopes in hard rock regions. The Tibet Plateau has been under an equilibrium condition between tectonic uplifting and denudation except for the mountain ranges. The plateau might have reached the present altitudes before the Quaternary.

关键词： planation denudation threshold landform evolution Tibet Plateau 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

Assessment and utilization of soil water resources

引用

Journal of Geographical Sciences 2001年第1期11卷 87-91页

作者： WANG Hui-xiao, LIU Chang-ming, YANG Zhi-feng (State key laboratory of Water environment Simulation, Beijing Normal University, Beijing 100875, china) State key laboratory of Water environment Simulation Beijing Normal University Beijing China

Based on the analyses of water interactions and water balance, this paper discusses the issues on the assessment and regulation of soil water resources, which lays the scientific basis for limited irrigation and water... 详细信息

关键词： soil water resources assessment water interactions water balance

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 heuristic path-estimating algorithm for large-scale real-time traffic information calculating

引用

Science china(Technological Sciences) 2008年第S1期51卷 165-174页

作者： L WeiFeng1,ZHU TongYu1,WU DongDong2,DAI Hong3 & HUANG Jian1 1 State key laboratory for Software Development environment,Beihang University,Beijing 100083,china 2 Beijing Transportation Information Center,Beijing 100055,china 3 College of Arts & Science,Beijing Union University,Beijing 100083,china 1. State key laboratory for Software Development environment Beihang University Beijing 100083 China 2. Beijing Transportation Information Center Beijing 100055 China 3. College of Arts & Science Beijing Union University Beijing 100083 China

As the original Global Position System (GPS) data in Floating Car Data have the accuracy problem,this paper proposes a heuristic path-estimating algorithm for large-scale real-time traffic information calculating. It uses the heuristic search method,imports the restriction with geometric operation,and makes comparison between the vectors composed of the vehicular GPS points and the special road network model to search the set of vehicular traveling route candidates. Finally,it chooses the most optimal one according to weight. Experimental results indicate that the algorithm has considerable efficiency in accuracy (over 92.7%) and com-putational speed (max 8000 GPS records per second) when handling the GPS tracking data whose sampling rate is larger than 1 min even under complex road network conditions.

关键词： path-estimating floating car data (FCD) road network vector GPS

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

Impacts of increased atmospheric CO_2 concentration on photosynthesis and growth of micro-and macro-algae

引用

Science china(Life Sciences) 2008年第12期51卷 1144-1150页

作者： WU HongYan1, ZOU DingHui1 & GAO KunShan2 1 Marine Biology Institute, Shantou University, Shantou 515063, china 2 State key laboratory of Marine environmental Science, Xiamen University, Xiamen 361005, china Marine Biology Institute Shantou University Shantou 515063 China State key laboratory of Marine environmental Science Xiamen University Xiamen 361005 China

Marine photosynthesis drives the oceanic biological CO2 pump to absorb CO2 from the atmosphere, which sinks more than one third of the industry-originated CO2 into the ocean. The increasing atmos-pheric CO2 and subsequent rise of pCO2 in seawater, which alters the carbonate system and related chemical reactions and results in lower pH and higher HCO3- concentration, affect photosynthetic CO2 fixation processes of phytoplanktonic and macroalgal species in direct and/or indirect ways. Although many unicellular and multicellular species can operate CO2-concentrating mechanisms (CCMs) to util-ize the large HCO3- pool in seawater, enriched CO2 up to several times the present atmospheric level has been shown to enhance photosynthesis and growth of both phytoplanktonic and macro-species that have less capacity of CCMs. Even for species that operate active CCMs and those whose photo-synthesis is not limited by CO2 in seawater, increased CO2 levels can down-regulate their CCMs and therefore enhance their growth under light-limiting conditions (at higher CO2 levels, less light energy is required to drive CCM). Altered physiological performances under high-CO2 conditions may cause genetic alteration in view of adaptation over long time scale. Marine algae may adapt to a high CO2 oceanic environment so that the evolved communities in future are likely to be genetically different from the contemporary communities. However, most of the previous studies have been carried out under indoor conditions without considering the acidifying effects on seawater by increased CO2 and other interacting environmental factors, and little has been documented so far to explain how physi-ology of marine primary producers performs in a high-CO2 and low-pH ocean.

关键词： CO2 photosynthesis growth phytoplankton macroalgae

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

Experimental study on the interaction between peat,lignite and germanium-bearing solution at low temperature

引用

Science china Earth Sciences 2005年第9期48卷 1411-1417页

作者： QI Huawen1,2, HU Ruizhong1 & QI Liang1 1. key laboratory of Ore Deposit Geochemistry, Chinese Academy of Sciences, Guiyang 550002, china 2. Department of Earth Science, Nanjing University, Nanjing 210093, china 1. key laboratory of Ore Deposit Geochemistry Chinese Academy of Sciences 550002 Guiyang China 2. Department of Earth Science Nanjing University 210093 Nanjing Chin

The interaction between peat, lignite and germanium(Ge)-bearing solution with an initial Ge concentration of 5 mg/L was studied at 25―100℃ and at pH 2.96―12.08. The results show that the apparent transfer ratios of peat and lignite for Ge in the solution were positively correlated with temperature in acid environment (initial pH=2.96), and the ratios (up to 86.5%) of lignite were obviously higher than those (up to 58.5%) of peat, but the organic transfer ratios of lignite were lower than those of peat. The activation energy values for interaction between peat, lignite and Ge-bearing solution are 30.96 and 15.67 kJmol?1, respectively. The strong acid (initial pH=2.96) and the strong alkaline (initial pH=12.08) environment contribute to the transfer of Ge in the solution. At 4environment (initial pH=6.38) conduces to the transfer of Ge into lignite. The interaction between peat, lignite and Ge-bearing solution are mainly attributable for the complexation of Ge with organic substrate. The experimental results from this study provide direct experimental evidence for the hydrothermal sedimentary genesis of abnormal enrichment of Ge in coal.

关键词： low temperature, peat, lignite, Ge4+, complexation.

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：