检索结果-南通市图书馆

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

长白山北坡森林群落结构组成及其海拔变化

生态学杂志 2003年第6期22卷 28-32页

作者：姜萍赵光叶吉崔国发邓红兵中国科学院沈阳应用生态研究所沈阳110016 北京林业大学资源与环境学院北京100083 中国科学院生态环境研究中心北京100085

对长白山北坡海拔 70 0～ 1.0 0m的 1.个森林群落进行了群落组成、结构随海拔上升变化情况的研究。结果表明 ,随着海拔的升高 ,群落的建群种组成、层次结构等 ,都表现出由复杂多样逐渐向简单单一过渡的变化趋势 ,从 70 0m至 1.0 0m ,针... 详细信息

对长白山北坡海拔 70 0～ 1.0 0m的 1.个森林群落进行了群落组成、结构随海拔上升变化情况的研究。结果表明 ,随着海拔的升高 ,群落的建群种组成、层次结构等 ,都表现出由复杂多样逐渐向简单单一过渡的变化趋势 ,从 70 0m至 1.0 0m ,针叶树所占的比例随海拔的升高呈明显的增加趋势 ,阔叶树比例随之减少 ,到林线时针阔叶树种均急剧减少 ,沿海拔梯度存在明显的树种更替现象。从群落的平均胸径及胸高断面积和可知 ,最大值出现于 90 0～ 1.0 0m及 1. 0 0m ,这 2个海拔段正是不同森林群落类型间的过渡区。除海拔 1.0 0m的岳桦林之外 ,其它群落径级结构都呈倒J形分布 ,即各径级树木中 ,更新幼苗、幼树在数量上占绝对优势 ,随着胸径的增大 ,立木株数逐渐减少 ,这种径级结构表明 ,长白山北坡各海拔群落更新良好 ,群落处于稳定的发展状态。

关键词：长白山森林群落结构海拔梯度

基施与叶面施硒肥对富硒镉污染农田水稻降镉增硒的效应

在线全文

学校读者我要写书评

暂无评论

农业环境科学学报 2024年第5期43卷 974-982页

作者：郑晶鲍广灵陶荣浩吴承龙马友华叶文玲农田生态保育与污染防控安徽省重点实验室安徽农业大学资源与环境学院合肥230031 石台富硒农业试验站石台县农业农村局安徽池州245100

为探讨基施硒肥和叶面施硒肥在轻度镉污染的富硒土壤中对水稻降镉增硒的效果,在田间试验条件下,通过设置基施硒肥、叶面施硒肥和基施硒肥+叶面施硒肥3个处理,以常规施肥作为对照,对成熟期水稻产量、各部位镉和硒含量、富集与转运系数以... 详细信息

为探讨基施硒肥和叶面施硒肥在轻度镉污染的富硒土壤中对水稻降镉增硒的效果,在田间试验条件下,通过设置基施硒肥、叶面施硒肥和基施硒肥+叶面施硒肥3个处理,以常规施肥作为对照,对成熟期水稻产量、各部位镉和硒含量、富集与转运系数以及土壤中镉的形态进行测定分析。结果表明:叶面施硒肥能显著提高水稻产量。基施硒肥后,土壤pH提高了0.1.个单位,提高率为3.01.,同时降低了土壤中镉的弱酸提取态含量,降低率为2.96%,促进了镉从弱酸提取态向可氧化态和残渣态转变,从而降低了土壤中镉的有效性。而叶面施硒肥能显著降低水稻对镉转运特别是秸秆到糙米的转运系数,降低率达1..1.%,同时提高水稻对硒的转运特别是根到秸秆的转运系数,提高率达1..69%。不同硒肥处理下,糙米中镉含量为0.1.9~0.1.3 mg·kg^(-1.,硒含量为0.21.~0.244 mg·kg^(-1.,不同硒肥处理均能使糙米达到降镉增硒的效果,且叶面施硒肥处理相较于基施硒肥处理的效果更好,并在基施硒肥和叶面施硒肥同时使用下的效果最佳,其对糙米中镉含量的降低率达26.39%,硒含量的提升率达41.50%。综上,在轻度镉污染的富硒土壤中,基施硒肥或叶面施硒肥均能有效降低水稻籽粒中镉含量并提高稻米对硒的富集,且基施硒肥+叶面施硒肥处理是降低糙米镉含量与提高糙米硒含量综合效果最好的一种措施。

关键词：水稻硒肥镉转运和累积

维普期刊数据库博看期刊

Spatial Information Research for Temperature and Precipitation Climate Data in Hengduan Mountains

在线全文

学校读者我要写书评

暂无评论

Meteorological and environmental Research 2011年第4期2卷 26-29页

作者： ye Jiang-xia {1. of resources, Southwest Forestry university, Kunming 650224, china

[Objective] The aim was to study the spatial information of temperature and precipitation data in Hengduan mountains. [Method] Considering GIS spatial interpolation and numerical statistics theory, spatial prediction were carried out to the ten {1.ars average temperature and precipitation flux observation data in 1.9 sparse meteorological stations in Hengduan Mountains. Based on the spatial range of geographic position of Hengduan Mountains, and 1.1.000 000 scale DEM as data sources, and using trend surface simulation and residual ordinary Kriging interpolation correction method, the spatial continuous surface for annual average temperature and precipitation were studied. [Result] It was scientific and reasonable to use certain unevenly distributed sparse climate observation station value, and by dint of trend simulation and residue interpolation method to get climate consecutive spatial result. This method can not only accurate the temperature and precipitation spatial distributions to grid point, but also can reflect macro and micro geography factors and topographic influence factor of variation. Furthermore, it can be predicted error term trend surface reasonable spatial distribution. Simulation results were basically in accordance with the objective law, and can be used for the region climate data spatial informatization simulation. [Conclusion] The study provided scientific spatial basic data for the further study of ecological and vegetation in Hengduan Mountains.

关键词： Hengduan Mountains Climate {1. Spatial information Trend simulation Residue ordinary Kriging interpolation china

Gravity and magnetic field feature for archaeology in site of the Emperor Qinshihuang mausoleum,china

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

Gravity and magnetic field feature for archaeology in site o...

地下水“三氮”污染来源及其识别方法研究进展

The 4th International Conference on environmental and Engineering Geophysics

作者： Bingqiang Yuan~1.Shiyi Liu~2 Guoming yu~2 Mingsheng Yang~3 Qingbo Duan~4 1.school of Petroleum {1. Xi’an Shiyou university Xi’an 71.065 china 2.Center of Development and Research Chinese Geological Survey Beijing 1.0037 china 3.The Second Integrated Geophysical Exploration Brigade Exploration and Empolder Bureau of Geological and Mineral {1. Shaanxi Province Xi’an 71.01. china 4.school of Archaeology and Museumology Northwestern university Xi’an 71.069 china

＜正＞The Emperor Qinshihuang mausoleum is abundant in the cultural relics at surface and underground and the kinds of cultural heritage sites are *** than 600 accompanying pits, tombs and ancient construction sites with different shape and different size have been discovered, a large numbers of those relics are still not be found at *** method validity has been tested on those sites known using high precision gravity and magnetic survey,which are for to explore the distribution of underground relics,to provide the proof in protecting such an important cultural relic in science and to choose geophysical prospecting method and technology being fit to existing character in the *** test results have showed that the range of ancient construction base site can be confirmed and the underground distribution can be conjectured by using high precision gravity *** is valid to explore the accompanying pits burned and also to find the accompanying tombs by using high precision magnetic *** test results have yet provided the foundation to explore the similar cultural relics in the Emperor Qinshihuang mausoleum area in future.

关键词： Emperor Qinshihuang mausoleum accompanying pits and tombs construction base gravity and magnetic field

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

环境科学 2018年第11期39卷 5266-5275页

作者：杜新强方敏冶雪艳吉林大学环境与资源学院长春130021 吉林大学地下水资源与环境教育部重点实验室长春130021

地下水"三氮"污染来源的识别研究对污染控制与修复有重要的意义.在阐述地下水"三氮"污染来源(大气氮沉降、土壤天然有机氮矿化、地表径流氮输入、人类活动氮排放等)及其在我国的分布特征的基础上,总结了国际上常用的"三氮"污染来源识别... 详细信息

地下水"三氮"污染来源的识别研究对污染控制与修复有重要的意义.在阐述地下水"三氮"污染来源(大气氮沉降、土壤天然有机氮矿化、地表径流氮输入、人类活动氮排放等)及其在我国的分布特征的基础上,总结了国际上常用的"三氮"污染来源识别方法,包括水化学方法、统计学相关方法、区域氮平衡法、稳定同位素示踪法及一些新型示踪方法.指出由于"三氮"污染来源的多样性及污染形成机制的复杂性,单一识别方法在应用中均有较明显的局限性,目前主流识别手段为稳定同位素示踪法与多种识别方法相综合.进一步提出要加强新型示踪方法的开拓、定量识别方法的优化,污染源识别与迁移转化机制、地下水补排条件、地下水-地表水转化关系等研究相结合为未来发展的主要趋势.

关键词：地下水 “三氮”污染污染来源污染源识别同位素示踪

信阳西部地区土地利用变化与地表水水质关系研究

在线全文

学校读者我要写书评

暂无评论

水电能源科学 2010年第5期28卷 29-32,129页

作者：董杰英陈启慧李琼芳蔡涛聂利群河海大学水文水资源与水利工程科学国家重点实验室江苏南京210098 河海大学水文水资源学院江苏南京210098 新余环保局江西新余338000

以信阳西部地区为例,选取该区域20世纪80、90年代和2000年后三期TM影像及1.80~2007年地表水水质资料,运用ArcGIS软件和SWAT模型,采用综合指数法及相关性分析法研究了土地利用变化与地表水水质的关系。结果表明:研究区内旱地、草地、水... 详细信息

以信阳西部地区为例,选取该区域20世纪80、90年代和2000年后三期TM影像及1.80~2007年地表水水质资料,运用ArcGIS软件和SWAT模型,采用综合指数法及相关性分析法研究了土地利用变化与地表水水质的关系。结果表明:研究区内旱地、草地、水体面积以较大变化率先减后增,水田、园地面积先增后减,林地面积变化不大,90年代后城乡用地大幅增长;地表水水质整体呈逐渐恶化趋势,主要污染因子为氨氮、总磷、挥发酚;在无点源污染的3个子流域,流域出口可溶性无机氮和总磷含量与旱地面积的变化相关性显著,其他土地利用方式对地表水水质影响不明显。

关键词：土地利用变化地表水水质信阳西部地区

Spatial patterns of terrestrial net ecosystem productivity in china during 1.81.2000

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2007年第5期50卷 745-753页

作者： tao Bo1. CAO MingKui1. LI KeRang1. GU FengXue1. JI JinJun1.2, HUANG Mei1.& ZHANG LeiMing1.1.Institute of Geographical Sciences and Natural {1. Research, Chinese Academy of Sciences, Beijing 1.01.1. china 2 Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 1.01.1. china 1. Institute of Geographical Sciences and Natural resources Research Chinese Academy of Sciences Beijing 100101 China 2. Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100101 China

As the third largest country in the world, china has highly variable {1. condition and eco- logical pattern in both space and time. Quantification of the spatial-temporal pattern and dynamic of terrestrial ecosystem carbon cycle in china is of great significance to regional and global carbon budget. In this study, we used a high-resolution climate database and an improved ecosystem process-based model to quantify spatio-temporal pattern and dynamic of net ecosystem productivity (NEP) in china and its responses to climate change during 1.81.to 2000. The results showed that NEP increased from north to south and from northeast to southwest. Positive NEP (carbon sinks) occurred in the west of Southwest china, southeastern Tibet, Sanjiang Plain, Da Hinggan Mountains and the mid-west of North china. Negative NEP (carbon sources) were mainly found in Central china, the south of Southwest china, the north of Xinjiang, west and north of Inner Mongolia, and parts of North china. From the 1.80s to 1.90s, the increasing trend of NEP occurred in the middle of Northeast china Plain and the Loess Plateau and decreasing trends mainly occurred in a greater part of Central china. In the study period, natural forests had minimal carbon uptake, while grassland and shrublands accounted for nearly three fourths of the total carbon terrestrial uptakes in china during 1.81.2000.

关键词： china terrestrial ecosystem carbon cycle spatial patterns climate change

在线全文

学校读者我要写书评

暂无评论

一种船舶操纵离线模拟系统及其应用

天津大学学报（自然科学与工程技术版） 2002年第3期35卷 281-284页

作者：张庆河韩涛李炎保刘晔杨希宏天津大学建筑工程学院天津300072 中交第一航务工程勘察设计院天津300222

在建立船舶操纵模拟自动舵系统的基础上建立了船舶操纵运动离线模拟系统 .该系统可以快速模拟船舶在风浪流和限制性航道等各种复杂外环境作用下的操纵运动 ,研究外荷载对船舶操纵的影响 ,从而可以从船舶安全出入港角度定量考虑港口航道... 详细信息

在建立船舶操纵模拟自动舵系统的基础上建立了船舶操纵运动离线模拟系统 .该系统可以快速模拟船舶在风浪流和限制性航道等各种复杂外环境作用下的操纵运动 ,研究外荷载对船舶操纵的影响 ,从而可以从船舶安全出入港角度定量考虑港口航道的优化设计问题 .实际应用表明。

关键词：船舶操纵离线模拟系统港口航道设计

Influence of Degree-Day Factor Variation on the mass Balance of Glacier No. 1.at the Headwaters of ürümqi River,{1.

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science 2013年第6期24卷 1008-1022页

作者：崔玉环叶柏生王杰刘友存 State Key Laboratory of Cryospheric Sciences Cold and Arid Regions Environment and Engineering Research InstituteChinese Academy of Sciences school of {1. and environmental Engineering Anhui University Key Laboratory of Water resources and Environment Tianjin Normal University

The degree-day factor （DDF） is a key parameter in the degree-day model, and the varia- tions in DDF have the significant effects on the accuracy of glacier mass balance modeling. In this study, Glacier No. 1.at the headwaters of Uriimqi （-~O）~Z~=） River in{1. was selected, and the estimated DDF by stakes-observed mass balance and meteorological data from 1.83-2006 was used to analyze the spatio-temporal variability of DDF and its influencing factors, such as climate condition, surface fea- ture, and topography. Then, the ablations from the 1.80s to 2000s were estimated using the degree-day modei, and the ablation change from the 1.80s to 2000s was divided into the changes caused by climate change and by the ice-surface feature. The following results were obtained：（1. The annual change in DDF for snow was not obvious, whereas that for ice increased, and the increasing trend on the lower glacier was more significant than that on the upper glacier because of decreased albedo caused by vari- ations in ice-surface feature; （2） The DDF for ice clearly decreased with altitude by approximately 0.046 and 0.043 mm.＇C-l-d-Lm-1.on the east and west branches, respectively, and the DDF of the west branch was obviously larger than that of the east branch in the same altitude belt; （3） the changes in mass balance in the summers from the 1.80s to 2000s were -391.and -467 mm on the east and west branches, respectively. Among the total changes, the components directly caused by climate change were -1.3 and -1.8 mm, whereas those indirectly caused by ice-surface feature change were -1.8 and -269 mm on the east and west branches, respectively.

关键词： degree-day factor mass balance,Glacier No. 1 climate change.