检索结果-南通市图书馆

Sediment transport and carbon sequestration characteristics along mangrove fringed coasts

Acta Oceanologica Sinica 2015年第2期34卷 21-26页

作者： TU Qiang YANG Shengyun ZHOU Qiulin YANG juan College of Ocean and Earth Science Xiamen University Third Institute of Oceanography State Oceanic Administration School of Marine Science China University of Geosciences

Mangroves play an important role in sequestering carbon and trapping sediments. However, the effectiveness of such functions is unclear due to the restriction of knowledge on the sedimentation process across the vegetation boundaries. To detect the effects of mangrove forests on sediment transportation and organic carbon sequestration, the granulometric and organic carbon characteristics of mangrove sediments were investigated from three vegetation zones of four typical mangrove habitats on the Leizhou Peninsula coast. Based on our results, sediment transport was often ＂environmentally sensitive＂ to the vegetation friction. A transition of the sediment transport mode from the mudflat zone to the interior/fringe zone was often detected from the cumulative frequency curve. The vegetation cover also assists the trapping of material, resulting in a significantly higher concentration of organic carbon in the interior surface sediments. However, the graphic parameters of core sediments reflected a highly temporal variability due to the sedimentation process at different locations. The sediment texture ranges widely from sand to mud, although the sedimentary environments are restricted within the same energy level along the fluvial-marine transition zone. Based on the PCA results, the large variation was mainly attributed to either the mean grain size features or the organic carbon features. A high correlation between the depth and δ13C value also indicated an increasing storage of mangrove-derived organic carbon with time.

关键词： mangroves grain size distribution sedimentary organic carbon Leizhou Peninsula

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

Pathologic research update of colorectal neuroendocrine tumors

引用

World Journal of Gastroenterology 2010年第14期16卷 1713-1719页

作者： Ni, Shu-juan Sheng, Wei-Qi Du, Xiang Fudan Univ Dept Pathol Canc Hosp Shanghai 200032 Peoples R China Fudan Univ Dept Oncol Shanghai Med Sch Shanghai 200032 Peoples R China

Colorectal neuroendocrine tumors (NETs) originate from neuroendocrine cells in the intestinal tract, and represent a small area within oncology, but one which has provided increasing new data during the past years. Although the World Health Organization has determined clinical and histological features to predict prognosis for such tumors, they may not be valid on an individual basis. We aim to give an overview of the recent findings with regard to pathology, molecular genetics and diagnosis of NETs.

关键词： Neuroendocrine tumors Carcinoid Colorectal World Health Organization classification Tumornode-metastases

来源：

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

拔节期渍水对软质小麦淀粉粒度分布与糊化特性的影响

引用

作物学报 2024年第7期50卷 1877-1884页

作者：陈娟杨婷婷闫素辉雍玉东张士雅李文阳安徽科技学院农学院安徽凤阳233100

为明确拔节期渍水对软质小麦淀粉粒度分布与糊化特性的影响。在大田条件下,于2021—2023年,选用软质小麦品种华成麦1688和荃麦725为试验材料,设对照(CK)和渍水(WL)2种处理,在小麦拔节期进行连续10 d的渍水处理,研究拔节期渍水对软质小... 详细信息

为明确拔节期渍水对软质小麦淀粉粒度分布与糊化特性的影响。在大田条件下,于2021—2023年,选用软质小麦品种华成麦1688和荃麦725为试验材料,设对照(CK)和渍水(WL)2种处理,在小麦拔节期进行连续10 d的渍水处理,研究拔节期渍水对软质小麦淀粉粒度分布及黏度参数的影响及其相互关系。结果表明,与对照相比,拔节期渍水胁迫通过降低小麦穗数、穗粒数及千粒重,从而降低小麦产量,籽粒湿面筋含量、蛋白质含量显著降低,淀粉含量显著增加。拔节期渍水胁迫抑制了小麦胚乳B淀粉的产生和生长,使小麦B型淀粉粒体积、表面积及数目百分比显著降低,其中主要影响2.8~10.0μm的淀粉粒;A型淀粉粒体积、表面积百分比显著增加,以影响其中10.0~22.0μm的淀粉粒为主,渍水胁迫对A型淀粉粒数目百分比无显著性影响。渍水胁迫后,面粉峰值黏度、低谷黏度、最终黏度、稀懈值及回升值显著增加。可见,拔节期渍水胁迫改变了小麦淀粉粒度分布,通过降低B型淀粉粒占比,增加A型淀粉粒占比,进而增加峰值黏度等黏度参数,最终影响小麦籽粒品质。

关键词：小麦淀粉粒淀粉粒度分布糊化特性渍水

来源：

维普期刊数据库博看期刊

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

Workability and Durability of Concrete Incorporating Waste Tire Rubber:A Review

引用

Journal of Renewable Materials 2023年第2期11卷 745-776页

作者： Peng Zhang Xixi Wang juan Wang Tianhang Zhang School of Water Conservancy Engineering Zhengzhou UniversityZhengzhou450001China

Environmental problems caused by waste tires are becoming increasingly *** is an urgent need to find a green way to dispose of waste tires,and scholars have made considerable efforts in this *** the construction industry,rubber extracted from waste tires can be added to concrete to alleviate environmental problems to a certain *** a new building material,rubber concrete has superior properties compared to ordinary concrete and has been widely used in many *** studies have been conducted worldwide to investigate the effect of waste tire rubber on the performance of *** has been reported that the addition of waste tire rubber has a significant influence on the performance of *** influences the hardened performance of rubber concrete,especially the *** on the current research results,the workability and durability of concrete manufactured with waste tire rubber,including water absorption and permeability,carbonation resistance,chloride ion permeability resistance,and freeze-thaw resistance,are summarized in this *** is concluded that the addition of waste tires has a negative effect on the workability of *** terms of durability,concrete exhibits better chloride ion penetration resistance and frost resistance,with a higher water absorption rate,and lower anti-permeability and carbonation resistance owing to the addition of waste tire rubber.

关键词： Rubber concrete waste tire rubber workability durability

来源：

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

TfOH/Fe（OTf）3 Cocatalyzed Reaction of Arylallenes with Alcohols for Structurally Diverse Indene Derivatives

引用

Chinese Journal of Chemistry 2018年第8期36卷 737-742页

作者： Congrong Liu Haiyun Zhang Lianghui Ding juan Liu School of Environment Engineering Nanjing Institute of Technology 1 Hongjingdadao Nanjing Jiangsu 212167 China Department of Chemistry University of Science and Technology of ChinaHefei Anhui 230026 China

The indene moiety is an important unit because of its presence in many chemical catalysts, functional materials and biologically relevant molecules. Herein, we report a facile reaction of arylallenes with benzylic or allylic alcohols through TfOH/Fe（OTf）3 cocatalyzed cleavage of sp3 carbon-oxygen. In the presence of 5 mol% TfOH and 5 mol% Fe（OTf）3, a range of arylallenes undergo carbocation initiated cyclization reaction with alkyl alcohols to give structurally diverse polysubstituted indenes in good to excellent yields. H2O is the sole byproduct that makes this transformation highly atom-economic and environmentally benign.

关键词： allenes alcohols cocatalyst electrophilic cyclization indenes

来源：

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

The Possible Effect of Climate Warming on Northern Limits of Cropping System and Crop Yield in China

引用

Agricultural Sciences in China 2011年第4期10卷 585-594页

作者： YANG Xiao-guang LIU Zhi-juan CHEN Fu College of Resources and Environmental Sciences China Agricultural University Beijing 100193 P.R. China College of Agronomy and Biotechnology China Agricultural University Beijing 100193 P.R.China

Significantly increasing temperature since the 1980s in China has become a consensus under the background of global climate change and how climate change affects agriculture or even cropping systems has attracted more and more attention from Chinese government and scientists. In this study, the possible effects of climate warming on the national northern limits of cropping systems, the northern limits of winter wheat and double rice, and the stable-yield northern limits of rainfed winter wheat-summer maize rotation in China from 1981 to 2007 were analyzed. Also, the possible change of crop yield caused by planting limits displacement during the periods 1950s-1981 and 1981-2007 was compared and discussed. The recognized calculation methods of agricultural climatic indices were employed. According to the indices of climatic regionalization for cropping systems, the national northern limits of cropping systems, winter wheat and double rice, and the stable-yield northern limits of rainfed winter wheat-summer maize rotation during two periods, including the 1950s-1980 and 1981-2007, were drawn with ArcGIS software. Compared with the situation during the 1950s- 1980, the northern limits of double cropping system during 1981-2007 showed significant spatial displacement in Shaanxi, Shanxi, Hebei, and Liaoning provinces and Beijing municipality, China. The northern limits of triple cropping system showed the maximum spatial displacement in Hunan, Hubei, Anhui, Jiangsu, and Zhejiang provinces, China. Without considering variety change and social economic factors, the per unit area grain yield of main planting patterns would increase about 54-106% if single cropping system was replaced by double cropping system, which turned out to be 27- 58% if double cropping system was replaced by triple cropping system. In Liaoning, Hebei, Shanxi, Shaanxi, Gansu, and Qinghai provinces, Inner Mongolia and Ningxia autonomous regions, China, the northern limits of winter wheat during 1981-200

关键词： climate warming the northern limits of cropping system the planting northern limits of winter wheat the planting northern limits of double rice crop yield

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

Relationship of atmospheric boundary layer depth with thermodynamic processes at the land surface in arid regions of China

引用

Science China Earth Sciences 2011年第10期54卷 1586-1594页

作者： ZHANG Qiang ZHANG Jie QIAO juan WANG Sheng Key Laboratory of Arid Climate Change and Reducing Disaster of Gansu Province Key Open Laboratory of Arid Climate Change and Disaster Reduction Lanzhou Institute of Arid Meteorology China Meteorological Administration Lanzhou 730020 China Key Laboratory of Meteorological Disasters (KLMD) Ministry of Education Nanjing Information Engineering University Nanjing 210044 China Meteorological Bureau of Xi' an City Xi'an 710016 China Institute of Atmospheric Sciences Lanzhou University Lanzhou 730000 China

The atmospheric boundary layer （ABL） is an important physical characteristic of the Earth＇s atmosphere. Compared with the typical ABL, the ABL in arid regions has distinct features and is formed by particular mechanisms. In this paper, the depth of the diurnal and nocturnal ABLs and their related thermodynamic features of land surface processes, including net radiation, the ground-air temperature difference and sensible heat flux, under typical summer and winter conditions are discussed on the basis of comprehensive observations of the ABL and thermodynamic processes at the land surface carried out in the extreme arid zone of Dunhuang. The relationships of the ABL depth in the development and maintenance stages with these thermodynamic features are also investigated. The results show that the depth of the ABL is closely correlated with the thermodynamic features in both development and maintenance stages and more energy is consumed in the development stage. Further analysis indicates that wind velocity also affects ABL development, especially the development of a stable boundary layer in winter. Taken together, the analysis results indicate that extremely strong thermodynamic processes at the land surface are the main driving factor for the formation of a deep ABL in an arid region.

关键词： arid region deep atmospheric boundary layer development and maintenance thermodynamic process at the land surface main driving factor

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

Global Helically Symmetric Solutions to 3D MHD Equations

引用

Acta Mathematicae Applicatae Sinica 2014年第2期30卷 347-358页

作者： Wen GAO Zhen-hua GUO Dong-juan NIU Northwest University School of Mathematical Sciences Capital Normal University

We prove the existence and uniqueness of global strong solutions to the Cauchy problem of the three-dimensional magnetohydrodynamic equations in R3 when initial data are helically symmetric. Moreover, the large-time b... 详细信息

关键词： magnetohydrodynamic equations helically symmetric solutions large-time behavior of solutions

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

Photosynthetic characteristics and nitrogen distribution of large-spike wheat in Northwest China

引用

Journal of Integrative Agriculture 2016年第3期15卷 545-552页

作者： WANG Li-fang CHEN juan SHANGGUAN Zhou-ping State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Northwest A&F University

The leaf photosynthesis and nitrogen（N） translocation in three large-spike lines and control cultivar（Xi＇nong 979） of winter wheat（Triticum aestivum L.） were studied in 2010–2011 and 2011–2012. The objectives of this study were to investigate the differences in the physiological characteristics of large-spike lines and control cultivar and identify the limiting factors that play a role in improving the yield of breeding materials. The average yield, grain number per spike, kernel weight per spike, and 1 000-kernel weight of the large-spike lines were 16.0, 26.8, 42.6, and 15.4%, respectively, significantly higher than those of control. The average photosynthetic rates（Pn） were not significant between the large-spike lines and control cultivar during the active growth period. The average PSII maximum energy conversion efficiency（Fv/Fm）, PSII actual quantum efficiency（Ф（PSII））, photochemical quenching coefficient（qP）, PSII reaction center activity（Fv′/Fm′） and water-use efficiency（WUE） of the large-spike lines were 1.0, 5.1, 3.6, 0.8, and 43.4%, respectively, higher than those of the control during the active growth stages. The N distribution proportions in different tissues were ranked in the order of grains〉culms＋sheathes〉rachis＋glumes〉flag leaves〉penultimate leaves〉remain leaves. This study suggested that utilization of the large-spike wheat might be a promising approach to obtain higher grain yield in Northwest China.

关键词： wheat nitrogen distribution large-spike lines photosynthetic characteristics yield

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

System Size Resonance Associated with Canard Phenomenon in a Biological Cell System

引用

Chinese Journal of Chemical Physics 2008年第6期21卷 521-525页

作者： juan Ma Hong-ying Li Zhong-huai Hou Hou-wen Xin Department of Chemical Physics University of Science and Technology of China Hefei 230026 China Hefei National Lab of Physical Science at Microscale University of Science and TechnoloEy of China Hefei 230026 China Department of Chemistry Hefei Teachers College Hefei 230000 China

The influence of internal noise on the calcium oscillations is studied. It is found that stochastic calcium oscillations occur when the internal noise is considered, while the corresponding deterministic dynamics only yields a steady state. Also,. the performance of such oscillations shows two maxima with the variation of the system size, indicating the occurrence of system size resonance. This behavior is found to be intimately connected with the canard phenomenon. Interestingly, it is also found that one of the optimal system sizes matches well with the real cell size, and such a match is robust to the variation of the control parameters.

关键词： Internal noise Calcium oscillations System size resonance Canard phenomenon

来源：

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

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：