检索结果-南通市图书馆

Morphological and physiological plasticity response to low nitrogen stress in black cottonwood(Populus deltoides Marsh.)

引用

Journal of Forestry Research 2022年第1期33卷 51-62页

作者： Cun chen Yanguang Chu qinjun Huang Changjun Ding Weixi Zhang Bo Li Jing Zhang Xiaohua su State Key Laboratory of Tree Genetics and Breeding Research Institute of ForestryChinese Academy of ForestryBeijing 100091People’s Republic of China Key Laboratory of Tree Breeding and Cultivation State Forestry and Grassland AdministrationBeijing 100091People’s Republic of China Co-Innovation Center for sustainable Forestry in Southern China Nanjing Forestry UniversityNanjing 210037People’s Republic of China

It is important to evaluate nitrogen use efficiency and nitrogen tolerance of trees in order to improve their *** this study,both were evaluated for 338 Populus deltoides genotypes from six *** plants were cultured under normal nitrogen(750μM NH_4 NO_3)and low nitrogen(5μM NH_4 NO_3)conditions for 3 ***,chlorophyll content and glutamine synthetase activity of each genotype were *** low nitrogen,heights,ground diameter,leaf area,leaf and root biomass,and chlorophyll contents were significantly lower than those under normal nitrogen *** analysis showed that nutrient distribution changed under different nitrogen *** was a negative correlation between leaf traits and root biomass under normal nitrogen level,however,the correlation became positive in low nitrogen ***,with the decrease of nitrogen level,the negative correlation between leaf morphology and chlorophyll levels became *** growth of the genotypes under the two treatments was evaluated by combining principal component analysis with a fuzzy mathematical membership function;the results showed that leaf traits accounted for a large proportion of the variation in the evaluation *** to the results of comprehensive evaluation of plants under the two treatments,the 338 *** genotypes could be divided into nine categories,with wide genotypic diversity in nitrogen use efficiency and low nitrogen *** a result,26 N-efficient genotypes and 24 N-inefficient genotypes were *** comparative analysis of their morphological and physiological traits under the two treatments,leaf traits could be significant indicators for nitrogen use efficiency and nitrogen tolerance,which is of considerable significance for breeding poplar varieties with high nitrogen use efficiencies.

关键词： Populus deltoides Nitrogen deficiency Nitrogen use efficiency Comprehensive evaluation Genotypic diversity

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

Numerical studies of stepwise radial fuel shuffling in a traveling wave reactor

引用

Science China(Technological Sciences) 2014年第6期57卷 1229-1237页

作者： ZHANG DaLin ZHENG MeiYin AN HongZhen chen XueNong TIAN WenXi QIU suiZheng su GuangHui School of Nuclear Science and Technology Xi'an Jiaotong University Nuclear and Radiation Safety Center Ministry of Environmental Protection of the People's Republic of China Institute for Nuclear and Energy Technologies Karlsruhe Institute of TechnologyEggenstein-Leopoldshafen D-76344Germany

The concept of travelling wave reactor(TWR)applies the mechanism of self-sustaining and propagating nuclear fission travelling waves in fertile media of 238U and 232Th to achieve very high fuel *** on this concept,a stepwise radial fuel shuffling strategy was proposed and applied to a sodium-cooled fast reactor(SFR)loading metallic 238U *** multi-group deterministic neutronic code ERANOS with JEFF3.1 data library was used as a basic tool to perform the neutronics and burnup *** inward fuel shuffling calculations were first performed in a 1-D cylindrical case for parametric understanding,and then extended to a 2-D R-Z *** shuffling calculations for the 1-D and 2-D SFR model yielded some interesting *** asymptotic keff varied parabolically with the characteristic fluence,while the burnup increased *** highest burnup achieved in 2-D case was 38%.The power peak shifted from the fuel outlet side(core centre)to the fuel inlet side(core periphery)in both 1-D and 2-D cases and the corresponding peaking factor decreased dramatically along with the characteristic *** present research demonstrated that the proposed stepwise radial fuel shuffling in the sodium fast reactor achieved the characteristics of the traveling wave reactor.

关键词： stepwise radial fuel shuffling traveling wave reactor asymptotic state numerical study

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

Enhanced strength and ductility in Ti46Al4Nb1Mo alloys via boron addition

引用

Journal of Materials Science & Technology 2022年第7期102卷 16-23页

作者： Yingmei Tan Ruirun chen Hongze Fang Yangli Liu Hongzhi Cui Yanqing su Jingjie Guo Hengzhi Fu National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of TechnologyHarbin 150001China School of Materials Science and Engineering Shandong University of Science and TechnologyQingdao 266590China

To improve the strength and ductility of Ti Al alloys by second phase, Ti46 Al4 Nb1 Mo alloys doped with different B content(0.4%, 0.8%, 1.2%, 1.6% and 2.0%, atomic percent, hereafter in at.%, referred to as TNMx B) were prepared. Macro/microstructure evolution, mechanical properties and deformation mechanisms of the alloys were studied systematically. Results showed that the microstructure of TNM-0.4 B and TNM-0.8 B alloy remained columnar dendrites, and the secondary dendritic arms of columnar grains were more obvious. When the content of B is 1.2%, the columnar dendrites transformed to equiaxed grains, and theα2/γ lamellae colony size was further refined in TNM-1.6 B and TNM-2.0 B alloy. The morphologies and kinds of the borides were changed with increasing B content, XRD results showed that Ti B phase appeared with 1.6%B content, and both Ti B and Ti B2 phase formed in TNM-2.0 B alloy. There were straight and curved Ti B phases located around grain boundaries in TNM-0.4 B and TNM-0.8 B alloy, and when the content of B increased to 1.2%, the curved Ti B phases were reduced, while the tiny and straight Ti B phases increased. With further increasing B content to 1.6% and 2.0%, the tiny and straight Ti B phases were coarser. Compressive testing results showed that the mechanical properties of the TNM alloy were enhanced with increasing B content. The maximum strength and strain of TNM alloy were 2339 MPa and33.7% with 1.6% B addition. The compressive strength and strain were mainly enhanced via refinement of lamellar colony and formation of Ti B, and it is found that pile-up of dislocations and deformed twins promoted by Ti B are predominant in improving the mechanical properties of TNM alloys with higher strength and strain.

关键词： TiAl alloy TiB Microstructure Mechanical properties

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

金属离子掺杂氧化锌的制备与光催化性能研究综合实验

引用

化学教育（中英文） 2024年第20期45卷 29-34页

作者：姚平平龙应钊杨昊宇黄钰钦杨启帆崔天奕苏佳正华东理工大学化学与分子工程学院上海200237

以无机化学、光化学为知识背景,以实现“双碳目标”为核心理念,采用直接沉淀法制备了3种金属离子掺杂氧化锌。实验包括8个环节:文献调研、实验方案确定、材料合成、材料表征、光催化性能探研、数据处理与分析、报告撰写和PPT分享交流等... 详细信息

以无机化学、光化学为知识背景,以实现“双碳目标”为核心理念,采用直接沉淀法制备了3种金属离子掺杂氧化锌。实验包括8个环节:文献调研、实验方案确定、材料合成、材料表征、光催化性能探研、数据处理与分析、报告撰写和PPT分享交流等。该综合性实验,能帮助学生融会贯通无机化学、光化学、仪器分析化学和结构化学的相关知识,体验高科技仪器设备的技术优势,在小组协作中培养朋辈相互学习、合作共赢、勇攀高峰的科学研究精神。

关键词： ZnO 金属离子掺杂光催化

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

Macrophage inflammatory protein-2 as mediator of inflammation in acute liver injury

引用

World Journal of Gastroenterology 2017年第17期23卷 3043-3052页

作者： Chao-Chao qin Yan-Ning Liu Ying Hu Ying Yang Zhi chen State Key Laboratory for Diagnosis and Treatment of Infectious Diseases The First Affiliated HospitalZhejiang University School of Medicine Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases

Macrophage inflammatory protein(MIP)-2 is one of the CXC chemokines and is also known as chemokine CXC ligand(CXCL2). MIP-2 affects neutrophil recruitment and activation through the p38 mitogen-activatedprotein-kinase-dependent signaling pathway, by binding to its specific receptors, CXCR1 and CXCR2. MIP-2 is produced by a variety of cell types, such as macrophages, monocytes, epithelial cells, and hepatocytes, in response to infection or injury. In liver injury, activated Kupffer cells are known as the major source of MIP-2. MIP-2-recruited and activated neutrophils can accelerate liver inflammation by releasing various inflammatory mediators. Here, we give a brief introduction to the basic molecular and cellular sources of MIP-2, and focus on its physiological and pathological functions in acute liver injury induced by concanavalin A, lipopolysaccharides, irradiation, ischemia/reperfusion, alcohol, and hypoxia, and hepatectomy-induced liver regeneration and tumor colorectal metastasis. Further understanding of the regulatory mechanisms of MIP-2 secretion and activation may be helpful to develop MIP-2-targeted therapeutic strategies to prevent liver inflammation.

关键词： Macrophage inflammatory protein-2 Liver injury Polymorphonuclear neutrophils Macrophages Inflammation

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

Spatial distribution of Cd and Cu in soils in Shenyang Zhangshi Irrigation Area(SZIA),China

引用

Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2008年第3期9卷 271-278页

作者： Li-na suN Xiao-bo YANG Wen-qing WANG Li MA su chen Key Laboratory of Eco-Remediation of Contaminated Environment and Resourcilization Technology Shenyang University Shenyang 110044 China Liaoning Geology Academe Shenyang 110032 China

Heavy metal contamination of soils,derived from sewage irrigation,mining and inappropriate utilization of various agrochemicals and pesticides,and so on,has been of wide concern in the last several *** Shenyang Zhangshi Irrigation Area(SZIA) in China is a representative area of heavy metal contamination of soils resulting from sewage irrigation for about 30 *** study investigated the spatial distribution and temporal variation of soil cadmium(Cd) and copper(Cu) contamination in the *** soil samples were collected from the SZIA in 1990 and 2004;Cd and Cu in soils was analyzed and then the spatial distribution and temporal variation of Cd and Cu in soils were modeled using Kriging *** results show that long-term sewage irrigation had caused serious Cd and Cu contamination in *** mean and the maximum of soil Cd are markedly higher than the levels in second grade standard soil(LSGSS) in China,and the maximum of soil Cu is close to the LSGSS in China in 2004 and is more than the LSGSS in China in *** contamination magnitude of soil Cd and the soil extent of Cd contamination had evidently increased since sewage irrigation ceased in *** contamination magnitude of soil Cu and the soil extent of Cu contamination had evidently increased in topsoil,but obviously decresed in *** soil contamination of Cd and Cu was mainly related to Cd and Cu reactivation of contaminated sediments in Shenyang Xi River and the import of Cd and Cu during *** eluviation of Cd and Cu in contaminated topsoil with rainfall and irrigation water was another factor of temporal-spatial variability of Cd and Cu contamination in soils.

关键词： Cadmium (Cd) Copper (Cu) Contamination of soils Spatial distribution Shenyang Zhangshi Irrigation Area (SZLA)

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

方格星虫体壁明胶的理化特征及功能特性分析

引用

食品与发酵工业 2024年第17期50卷 226-234页

作者：庄毓秀林海生秦小明曹文红陈忠琴高加龙郑惠娜章超桦广东海洋大学食品科技学院广东湛江524088 广东省水产品加工与安全重点实验室广东普通高等学校水产品深加工重点实验室国家贝类加工技术研发分中心(湛江)南海生物资源开发与利用协同创新中心广东湛江524088

以方格星虫为原料,分析体壁明胶(Sipunculus nudus body gelatine,SNBG)的结构与功能特性。热水法提取SNBG,分析其氨基酸组成,采用聚丙烯酰胺凝胶电泳法、质谱法、紫外光谱法、傅里叶红外光谱、扫描电子显微镜等对SNBG结构进行表征;通... 详细信息

以方格星虫为原料,分析体壁明胶(Sipunculus nudus body gelatine,SNBG)的结构与功能特性。热水法提取SNBG,分析其氨基酸组成,采用聚丙烯酰胺凝胶电泳法、质谱法、紫外光谱法、傅里叶红外光谱、扫描电子显微镜等对SNBG结构进行表征;通过测定SNBG的等电点、热变性温度、乳化活性指数(emulsifying activity index,EAI)、乳化稳定性指数(emulsion stability index,ESI)、起泡能力(foam capacity,FC)、泡沫稳定性(foam stability,FS)和持油性(oil holding capacity,OHC)研究其功能特性,并测定其DPPH自由基清除率与抑制酪氨酸酶活力。结果表明,热水提取SNBG富含甘氨酸(22.41%)、脯氨酸(6.62%)和疏水性氨基酸(27.89%),具有Ⅰ型胶原的亚基结构,且产生更多的小分子肽,纤维网状结构较少,出现不规则孔隙,形成光滑片状结构交联;光谱结果显示,SNBG在230 nm处有最大的紫外吸收峰,具有部分三螺旋结构,热水提取过程中大部分解折叠为α螺旋和无规则卷曲结构;此外,SNBG的热变性温度为42.70℃,等电点为4.37;10 mg/mL的SNBG,pH值为6时,EAI、ESI、FC、FS和OHC分别为99 m^(2)/g、40 min、60%、5.88%和12.67 g/g;SNBG在1~5 mg/mL质量浓度范围内,抗氧化活性与抑制酪氨酸酶活力呈浓度依赖关系,并且5 mg/mL的SNBG对DPPH自由基清除率和酪氨酸酶抑制率分别为30.46%和78.61%。综上所述,SNBG部分三螺旋结构解旋以光滑片状结构交联,具有抗氧化和抑制酪氨酸酶活力且功能特性较好,该研究可为SNBG在食品及化妆品领域的应用提供理论依据。

关键词：方格星虫明胶结构表征功能特性抑制酪氨酸酶活力

来源：

维普期刊数据库

同方期刊数据库

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

Preparation of poly(lactide-co-glycolide)microspheres and evaluation of pharmacokinetics and tissue distribution of BDMC-PLGA-MS in rats

引用

Asian Journal of Pharmaceutical Sciences 2018年第1期13卷 82-90页

作者： Guozhuan Li Liang Yao Jing Li Xiaoyan qin Zhen Qiu Weidong chen Anhui University of Chinese Medicine Hefei First People's Hospital

The aim of the present study was to develop a novel long-acting Poly(lactic-co-glycolic acid)(PLGA)-based microspheres formulation of Bisdemethoxycurcum(BDMC) by emulsionsolvent evaporation method. Meanwhile, the effects of the volume ratio of the dispersed phase and continuous phase, the concentration of PLGA and PVA, the theoretical drug loading and stirring speed were investigated. The mean diameter of the microspheres was 8.5 μm and the size distribution was narrow. The encapsulation efficiency(EE) and drug loading efficiency(DLE) of BDME loaded PLGA microspheres(BDMC-PLGA-MS) was 94.18% and 8.14%,respectively. In an in vitro study of drug release, it can be concluded that the BDMC-PLGAMS exhibited sustained and long-term release properties for 96 h. Stability studies suggested that the microspheres we prepared had a very good stability. Furthermore, the results of an in vivo study indicated that the BDMC-PLGA-MS had sustained release effect and was mainly distributed in the lung tissue, and less distribution in other tissues, which indicated that microspheres could be an effective parenteral carrier for the delivery of BDMC in lung cancer treatment.

关键词： Bisdemethoxycurcumin Microsphere Poly (lactic-co-glycolic acid) Solvent evaporation method Pharmacokinetics

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

基于改进人工势场的无人飞行器三维路径规划

引用

云南电力技术 2024年第3期52卷 64-68页

作者：余顺金冯建辉秦建明陈乐云南电网有限责任公司怒江供电局云南怒江673100

为了在森林火灾中为无人飞行器(UAV)寻找安全路径,提出了一种基于改进的人工势场(APF)的全局路径规划方法。该方法采用网格模型对三维空间中的威胁进行建模,然后以目标为引力源建立引力场,以威胁为斥力源建立斥力场。同时,改进了引力场... 详细信息

为了在森林火灾中为无人飞行器(UAV)寻找安全路径,提出了一种基于改进的人工势场(APF)的全局路径规划方法。该方法采用网格模型对三维空间中的威胁进行建模,然后以目标为引力源建立引力场,以威胁为斥力源建立斥力场。同时,改进了引力场和斥力场的建模,克服了传统人工势场的缺点;再配合动态避障,无人机就能快速躲避动态障碍物的威胁。仿真结果证明,该方法能在给定环境下获得最优路线。

关键词：无人机路径规划人工势场避障

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

Incidence and mortality of laryngeal cancer in China,2008–2012

引用

Chinese Journal of Cancer Research 2018年第3期30卷 299-306页

作者： Yuqin Liu qin Zhao Gaoheng Ding Yitong Zhu Wenying Li Wanqing chen Central Cancer Registry of Gansu Gansu Cancer Hospital National Cancer Center/Cancer Hospital Chinese Academy of Medical Sciences & Peking Union Medical College

Objective：To analyze the incidence and mortality rates of laryngeal cancer in China from 2008 to ***：Incident and death cases of laryngeal cancer were retrieved from the National Central Cancer Registry（NCCR）database collecting from 135 cancer registries in China during 2008–*** crude incidence and mortality rates of laryngeal cancer were calculated by area（urban/rural）,region（eastern,middle,western）,gender and age group（0,1–4,5–9,…,85＋）.China census in 2000 and Segi’s world population were applied for age standardized *** Point（Version 4.***.0.1）model was used for time trend ***：The crude incidence rate of laryngeal cancer was 1.86/100,000 ranked the 21st in overall *** age-standardized incidence rates by China population（ASIRC）and by World population（ASIRW）were1.22/100,000 and 1.23/100,000,*** crude mortality of laryngeal cancer in China was 1.01/100,000and it was the 21st cause of cancer-related death in overall *** the age-standardized mortality rates by Chinese standard population（ASMRC）and by world standard population（ASMRW）were 0.63/100,*** and mortality rates of laryngeal cancer were higher in males than in females and higher in urban areas than in rural *** areas had the highest incidence and mortality rates followed by eastern and western *** and mortality rates of laryngeal cancer retained low level before age of 40 years old but increased greatly after and peaked in age group of *** showed significant down trends in recent 10 years by 1.27%annually[95%confidence interval（95%CI）：–2.2%,–0.3%].Mortality declined in females sharply by 5.18%per year although stable in males and both sexes ***：Appropriate targeted prevention,early detection and treatment programs should be carried out to control the local burden of laryngeal cancer.

关键词： Laryngeal cancer incidence mortality 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

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：