检索结果-南通市图书馆

Critical phosphorus concentrations in winter wheat genotypes with various phosphorus efficiencies

Journal of Environmental sciences 1999年第1期11卷 79-85页

作者： Wang Qing ren, Li Ji yun Research center for Eco Environmental sciences,{2., beijing 100085, china Li Zhen sheng Research institute of Genetics,{2., beijing 100101, china

Under greenhouse conditions, a pot experiment was conducted to seek critical phosphorus concentrations of wheat genotypes with high and low phosphorus use efficiency. Results indicated that low efficient genotype was much more sensitive to phosphorus deficiency, with low or without phosphorus application, seed yield and dry matter of biomass were much lower. The yield of all the genotypes gradually got higher as application rate increased, but high efficient genotype——Lofflin produced relatively higher yields of seeds and biomass with low or without phosphorus input. Highly tolerate to low availability of soil phosphorus and efficient activation and absorption for soil unavailable phosphorus had been displayed. As application rates increased, yields of both genotypes were increased but high efficient genotype maintained stable while low efficient one showed continuously increase with remuneration decrease progressively. Critical phosphorus concentrations in high efficient genotypes of winter wheat were lower than that in low efficient ones and changed with various development stages, for example, at seedling state, the concentrations of high efficient genotype were 4.50—4.60 g/kg while low efficient one was 5.0 g/kg. They were 2.2.—2.30 g/kg and 2.52.g/kg at flower stage, 1.96—2.05 g/kg and 2.15 g/kg at maturity respectively. But the values in seeds were reversal, higher in high efficient genotype(4.05—4.10 g/kg) than that in low efficient(3.90 g/kg). Therefore, phosphorus high efficient genotypes belong to the phosphorus resource saving type.

关键词： critical phosphorus concentration wheat genotypes phosphorus efficiency.

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

Adsorption of atrazine by natural organic matter and surfactant dispersed carbon nanotubes

引用

Journal of Environmental sciences 2010年第8期22卷 1195-1202页

作者： Baoyou Shi, Xiaoyan Zhuang, Xiaomin Yan, Jiajuan Lu, Hongxiao Tang State Key Laboratory of Environmental Aquatic Chemistry, Research center for Eco-Environmental sciences,{2., beijing 100085, china. State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China

The aggregation and dispersion behaviors of carbon nanotubes （CNTs） can regulate the environmental spread and fate of CNTs, as well as the organic pollutants adsorbed onto them. In this study, multi-walled carbon nanotubes （MWNTs） and single-walled carbon nanotubes （SWNTs） were surface modified with humic acids from different sources and with surfactants of different ionic types. The dispersion stability of surface modified CNTs was observed by UV-Vis spectrophotometry. The effect of humic acid and surfactant dispersion on the adsorption of atrazine by CNTs was investigated by batch equilibrium experiments. Both humic acid and surfactant could effectively disperse MWNTs, but not SWNTs, into stable suspensions under the studied conditions. Surface modified CNTs had a greatly reduced capacity for adsorption of atrazine. The inhibitory effect of peat humic acid was relatively stronger than that of soil humic acid, but the two surfactants had a similar inhibitory effect on atrazine adsorption by the two CNT types. Increases in surfactant concentration resulted in rapid decreases in the adsorption of atrazine by CNTs when the surfactant concentration was less than 0.5 critical micelle concentration.

关键词： carbon nanotubes adsorption dispersion atrazine

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

用聚苯乙烯小球模拟生物组织中的光强分布

引用

物理学报 2003年第2期52卷 324-327页

作者：郭红莲程丙英张道中中国科学院物理研究所凝聚态物理中心光物理实验室北京100080

用水中周期排列的直径为 3μm的单层聚苯乙烯小球以及单个聚苯乙烯小球模拟对光敏感的生物组织 ,如绿色植物叶肉细胞、动物皮肤的表皮细胞、苍蝇蜜蜂等的复眼以及一种海蛇尾背部的光敏器官的光强分布 .通过观测聚苯乙烯小球在不同深度... 详细信息

用水中周期排列的直径为 3μm的单层聚苯乙烯小球以及单个聚苯乙烯小球模拟对光敏感的生物组织 ,如绿色植物叶肉细胞、动物皮肤的表皮细胞、苍蝇蜜蜂等的复眼以及一种海蛇尾背部的光敏器官的光强分布 .通过观测聚苯乙烯小球在不同深度的光强分布 ,发现随着深度的改变其光强分布是截然不同的 .在小球的横截面上 ,光强分布不很均匀而且呈有规律的花纹图案 .在小球的外面 ,光强分布表现为独立的透镜成像分布 .周期排列的小球与单个小球在其横截面上的光强分布也完全不同 ,前者的光强分布表现出球与球之间很大的相关性 .

关键词：聚苯乙烯小球模拟生物组织周期排列光强分布

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

Contradiction between strong lensing statistics and a feedback solution to the cusp/core problem

引用

Research in Astronomy and Astrophysics 2010年第12期10卷 1215-1222页

作者： Stacy McGaugh Department of Astronomy University of MarylandCollege Park

Standard cosmology has many successes on large scales, but faces some fundamental difficulties on small, galactic scales. One such difficulty is the cusp/core problem. High resolution observations of the rotation curves for dark matter domi- nated low surface brightness （LSB） galaxies imply that galactic dark matter halos have a density profile with a flat central core, whereas N-body structure formation simula- tions predict a divergent （cuspy） density profile at the {2.. It has been proposed that this problem can be resolved by stellar feedback driving turbulent gas motion that erases the initial cusp. However, strong gravitational lensing prefers a cuspy density profile for galactic halos. In this paper, we use the most recent high resolution observations of the rotation curves of LSB galaxies to fit the core size as a function of halo mass, and compare the resultant lensing probability to the observational results for the well defined combined sample of the Cosmic Lens All-Sky Survey （CLASS） and Jodrell Bank/Very Large Array Astrometric Survey （JVAS）. The lensing probabilities based on such density profiles are too low to match the observed lensing in CLASS/JVAS. High baryon densities in the galaxies that dominate the lensing statis- tics can reconcile this discrepancy, but only if they steepen the mass profile rather than making it more shallow. This places contradictory demands upon the effects of baryons on the central mass profiles of galaxies.

关键词： cosmology: theory -- dark matter -- galaxies: halos -- gravitationallensing: strong

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

Construction and Physical Properties of a Single Molecular Device

Construction and Physical Properties of a Single Molecular D...

引用

中国化学会第2.届学术年会纳米化学分会场

作者： Hongjun Gao beijing National Laboratory of condensed {2. physics & institute of physics, chinese academy of sciences, PO Box 603, beijing 100190, china

＜正＞Constructing single molecular devices of functionalities has stimulated a great interest in the past decades. One of the challenges in this field is to make the single molecule stably connected to a single metal atom on metal surfaces, and further to make the molecule create electric energy and optical/electro radiation by rotating the molecule.

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

厚度与应变效应对La_(0.67)Ca_(0.33)MnO_3薄膜电输运与居里温度的影响

引用

物理学报 2004年第11期53卷 3909-3915页

作者：熊昌民孙继荣王登京沈保根中国科学院物理研究所与凝聚态物理中心磁学国家重点实验室北京100080

在厚度为 2.5— 4 0 0nm范围内 ,系统地研究了 (0 0 1)SrTiO3(STO) ,(0 0 1)LaAlO3(LAO)衬底上La0 6 7Ca0 33MnO3(LCMO)薄膜的电输运与居里温度TC 随薄膜厚度及衬底的变化 .结果表明 ,随薄膜变薄 ,电阻率 ρ增加 ,TC降低 .对于同一薄... 详细信息

在厚度为 2.5— 4 0 0nm范围内 ,系统地研究了 (0 0 1)SrTiO3(STO) ,(0 0 1)LaAlO3(LAO)衬底上La0 6 7Ca0 33MnO3(LCMO)薄膜的电输运与居里温度TC 随薄膜厚度及衬底的变化 .结果表明 ,随薄膜变薄 ,电阻率 ρ增加 ,TC降低 .对于同一薄膜厚度 ,LCMO STO薄膜的 ρ大于LCMO LAO基上的薄膜的 ρ .TC与衬底的依赖关系则与 ρ相反 .分析表明 ,LCMO薄膜的低温区电阻温度 (ρ T)符合关系式 ρ =ρ0 +Bωs sinh2.(ωs 2. kBT) +CTn,其中 ρ0 为剩余电阻 ;等号右端第二项反映软光学模声子对电子散射的贡献 ;第三项包括其余可能散射机理在电输运过程中所起的作用 ;B ,ωs(软光学模声子的平均频率 )与C都为拟合系数 .高温区的电输运则由小极化子跃迁模型 ρ =DT×exp(Ea kBT)描述 (Ea为极化子激发能 ) .根据 ρ0 ,ωs,Ea以及TC变化 ,初步讨论了薄膜中的厚度与应变效应 .进一步研究发现ωs,Ea的变化与TC 相关 ,从而说明极化子效应为影响TC

关键词： La0.67Ca0.33MnO3 声子薄膜厚度应变效应极化子效应激发能电子散射衬底输运 DT

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

Electrical and Optical Properties of Strongly Reduced Epitaxial BaTiO3-x Thin Films Grown by Laser Molecular Beam Epitaxy

Electrical and Optical Properties of Strongly Reduced Epitax...

引用

第五届全国光学前沿问题研讨会

作者： Chen Zhenghao Zhao Tong Chen Fan Lu Huibin Yang Guozhen (Laboratory of Optical physics,institute of physics and center for condensed matter physics,The chinese academy of sciences,beijing 100080)

It is well known that stoichiometric barium titanate (BaTiO) is ***,electrical conduction will be induced either through reduction or through im- purity *** to its ferroelectric proper- ties,the electrical trausport properties of BaTiO,espe- cially the oxygen dcficient BaTiO(i.e.,BaTiOare not well understood so *** this work,a series of

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Exact solution of some spin-ladder models

Exact solution of some spin-ladder models

引用

CCAST“可积系统”研讨会

作者： Yupeng WangLaboratory of Ultra-Low Temperature physics & center for {2. matter physics, chinese academy of sciences, P. O. Box 2.11, beijing 100080, People''sRepublic of china

＜正＞We study some integrable spin-ladder models with nearest-neighbor exchanges and biquadratic *** the Betheansatz solutions of the model hamiltonians,the possible phases inthe ground state,the possible fixed points of the systems and thequantum critical behavior at the critical points are *** lattice model based on a doped spin ladder is ***,***,***

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Defects in La2.uO4 and La1.86Sr0.14CuO4 single crystals

引用

工程科学学报 2005年第2期 244-244页

作者： YANG Wei, JIA Liansuo, CHEN Xiaolong, and WANG Cong center of Materials physics and Chemistry, School of {2., Beihang University, beijing 100083, china institute of physics and center for condensed matter physics, chinese academy of sciences, beijing 100080, china

La2.uO4 and La1.86Sr0.14CuO4 single crystals were obtained by traveling solvent floating zone method. There were five kinds of defects in these single crystals: cracks, inclusions, gas bubbles, unhomogeneous distribution of Sr2., and substructures. CH3COOH aqueous solution was used to etch these single crystals, and the etch-pit density was calculated. The formation mechanism of these defects was discussed. It is suggested that the good preparation of raw materials and the stringent growth conditions play an important role in growing high quality single crystals.

关键词： defects TSFZ method etch-pit density

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

Scaling anomalous Hall effect in CoFeB based thin films

Scaling anomalous Hall effect in CoFeB based thin films

引用

2.12.国功能新材料学术论坛暨第三届全国电磁材料及器件学术会议

作者： T.Zhu institute of physics and beijing National Laboratory for {2. matter physics, chinese academy of sciences,beijing 100190,P.R.china

The anomalous Hall effect(AHE)in ferromagnetic materials has been attracting the continuous interest of researchers due to its controversial physical *** this presentation,the AHE scaling properties of the CoFeB based thin films have been investigated. The perpendicular multilayers of[CoFeB(t:0.3-0.7)/Pt(1-5)] (numbers are nominal thicknesses in nanometers)were deposited on a thermally oxidized silicon wafer by DC magnetron *** temperature dependence of the longitudinal resistivity,p,can be approximately fitted by a linear function of T, indicating the electron-magnon scattering dominates the resistivity of the *** is found that the related anomalous Hall resistivity obeys the common scaling relation of R=ap+bp,where the first term and the second term represent for the skew scattering mechanism and side jump mechanism,***,the AHE comes from a small side jump contribution combines with a large skew scattering component,which is in contradiction to the conventional perpendicular Co/Pt *** experiment also shows that the skew scattering anomalous Hall conductivity exhibits a quadratic dependence of the magnetization,σ∝M(T).Due to the increase of the interface roughness with the increase of the number of the CoFeB/Pt bilayer,N,the skew scattering component is enhanced.

关键词：

来源： cnki会议评论

在线全文

cnki会议

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：