检索结果-南通市图书馆

Predicting Potential Distribution of Tibetan Spruce (Picea smithiana) in Qomolangma (Mount Everest) National Nature Preserve Using Maximum Entropy Niche-based Model

在线全文

学校读者我要写书评

暂无评论

Chinese Geographical Science 2011年第4期21卷 417-426页

作者： zhang jiping zhang Yili LIU Linshan NIE Yong Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China Graduate University of Chinese Academy of Sciences Beijing 100049China Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China

Tibetan spruce (Picea smithiana) is an endemic species of the Himalayas,and it distributes only in a re-stricted area with very low *** address the lack of detailed distributional information,we used maximum en-tropy (Maxent) niche-based model to predict the species' potential distribution from limited occurrence-only *** location data of ***,relative bioclimatic variables,vegetation data,digital elevation model (DEM),and the derived data were analyzed in *** receiver operating characteristic (ROC) curve was applied to assess the prediction *** Maxent jackknife test was performed to quantify the training gains from data layers and the response of *** distribution to four typical environmental variables was *** show that the model performs well at the regional *** is a potential for continued expansion of *** population numbers and distribution in *** potentially distributes in the lower reaches of Gyirong Zangbo and Poiqu rivers in Gyirong and Nyalam counties in Qomolangma (Mount Everest) National Nature Preserve (QNNP),*** species prefers warm temperate climate in mountain area and mainly distributes in needle-leaved evergreen closed to open forest and mixed forest along the river valley at relatively low altitudes of about 2000-3000 *** simulations suggest that distribution patterns of rare species with few species numbers can be well predicted by Max-ent.

关键词： Picea smithiana maximum entropy niche-based model potential distribution Qomolangma (Mount Ev-erest) National Nature Preserve (QNNP)

Impact of livelihood diversification of rural households on their ecological footprint in agro-pastoral areas of northern China

在线全文

学校读者我要写书评

暂无评论

Journal of Arid Land 2015年第5期7卷 653-664页

作者： HAO Haiguang zhang jiping LI Xiubin zhang Huiyuan zhang Qiang Chinese Research Academy of Environmental Sciences Beijing Municipal Research Institute of Environmental Protection Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences

Human-environment relationship is a focus of academic researches and an understanding of the rela- tionship is important for making effective policies and decisions. In this study, based on rural household survey data of Taibus Banner, Duolun county and Zhengxiangbai Banner in the Inner Mongolia autonomous region of China, we identified the impact of livelihood diversification on ecosystems in these agro-pastoral areas by using the ecological footprint theory and methodology together with the one-way analysis of variance （ANOVA） and correlation analysis methods. In 2011, the total ecological footprint of consumption （EFC） was 0.665 g hm2, and the total ecological footprint of production （EFP） was 2.045 g hm2, which was more than three times the EFC. The ecological footprint of arable land consumption （EFAC） accounted for a large proportion of the EFC, and the ecological footprint of grassland production （EFGP） occupied a large proportion of the EFP. Both the ecological footprint of grassland consumption （EFGC） and EFGP had a significant positive correlation with the income, indicating that income was mainly depended on livestock production and the households with higher incomes consumed more livestock prod- ucts. The full-time farming households （FTFHs） had the highest EFP, ecological footprint of arable land production （EFAP）, EFGP and EFGC, followed by the part-time farming households （PTFHs） and non-farming households （NFHs）, which indicated that part-time farming and non-farming employment reduced the occupancy and con- sumption of rural households on local ecosystems and natural resources to some extent. When farming households engaged in livestock rearing, both the EFAP and EFAC became smaller, while the EFP, EFC, EFGC and EFGP increased significantly. The differences in ecological footprints among different household groups should be taken into account when making ecosystem conservation policies. Encouraging the laborers who have the advantages of participati

关键词： ecological footprint livelihood diversification livestock rearing non-farming employment rural households agro-pastoral area

Carbon storage of a subtropical forest ecosystem: a case study of the Jinggang Mountain National Nature Reserve in south-eastern China

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2019年第3期30卷 1011-1021页

作者： jiping zhang Linbo zhang Haiguang Hao Chunlan Liu Hui Wang Beijing Municipal Research Institute of Environmental Protection Beijing 100037People’s Republic of China Chinese Research Academy of Environmental Sciences Beijing 100012People’s Republic of China

The carbon cycle of forest ecosystems plays a key role in regulating CO2 concentrations in the atmosphere. Research on carbon storage estimation of forest ecosystems has become a major research topic. However, carbon budgets of subtropical forest ecosystems have received little attention. Reports of soil carbon storage and topographic heterogeneity of carbon storage are limited. This study focused on the Jinggang Mountain National Nature Reserve as an example of a mid-subtropical forest and evaluated soil and vegetation carbon storage by field sampling combined with GIS, RS and GPS technology. We classified the forest into nine forest types using ALOS high-resolution remote sensing images. The evergreen broad-leaved forest has the largest area, occupying 26.5% of the total area, followed by coniferous and broad-leaved mixed forests and warm temperate coniferous forest, occupying 24.2 and 22.9%, respectively. The vegetation and soil carbon storage of the whole forest ecosystem were 1,692,344 and 5,514,707 t, with a carbon density of 7.4 and 24.2 kg/m^2, respectively, which suggests that the ecosystem has great carbon storage capacity. The topographic heterogeneity of the carbon storage was also analysed. The largest vegetation storage and soil storage is at 700–800 and 1000–1100 m, respectively. The vegetation carbon storage is highest in the southeast, south and southwest.

关键词： Vegetation carbon storage Soil carbon storage Mid-subtropical forest ecosystem Jinggang Mountain National Nature Reserve

Agricultural land use intensity study in Taibus Banner, and its determinants： a case Inner Mongolia, China

在线全文

学校读者我要写书评

暂无评论

Frontiers of Earth Science 2015年第2期9卷 308-318页

作者： Haiguang HAO Xiubin LI Minghong TAN jiping zhang Huiyuan zhang Chinese Research Academy of Environmental Sciences Beijing 100012 China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China Beijing Municipal Research Institute of Environmental Protection Beijing 100037 China

Based on rural household survey data from Taibus Banner, in the Inner Mongolia Autonomous Region, China, this study separately categorizes agricul- tural land use intensity into labor intensity, capital intensity, the intensity of labor-saving inputs, and the intensity of yield-increasing inputs, and then analyzes their determinants at the household level. The findings reveal that within the study area：（1） labor intensity is higher and capital intensity is lower than in the major grain-producing and economically developed areas of eastern and central China; （2） the most widely planted crops are those with the lowest labor intensity （oats） and capital intensity （benne）; （3） there are marked differences in agricultural land use intensity among households; a major factor affecting land use decision-making is the reduced need for labor intensity for those households with high opportunity costs, such as those with income earned from non-farming activities which alleviates financial constraints and allows for increased capital intensity. As a result, these households invest more in labor-saving inputs; （4） households with a larger number of workers will allocate adequate time to manage their land and thus they will not necessarily invest more in labor-saving inputs. Those households with more land to manage tend to adopt an extensive cultivation strategy. Total income has a positive impact on capital intensity and a negative impact on labor intensity. House- holds that derive a higher proportion of their total income through farming are more reliant upon agriculture, which necessitates significant labor and yield-increasing inputs. Finally, the authors contend that policy makers should clearly recognize the impacts of non-farming employment on agricultural land use intensity. In order to ensure long- term food security and sustainable agricultural develop-ment in China, income streams from both farming and non- farming employment should be balanced.

关键词： agricultural land use intensity labor intensity,capital intensity opportunity cost of farm workers TaibusBanner

在线全文

学校读者我要写书评

暂无评论

FT-粗糙集模型的一些性质

泉州师范学院学报 2024年第2期42卷 1-9页

作者：张纪平周缪娟李进金泉州师范学院数学与计算机科学学院福建泉州362000 闽南师范大学数学与统计学院福建漳州363000

T-粗糙集是Pawlak粗糙集理论发展过程中的一个重要模型,已成功应用于数据挖掘等诸多领域.FT-粗糙集模型能够在保持数据的完整性下处理连续型数据,是对仅能处理离散型数据的T-粗糙集模型上的发展.文章引入模糊近似空间(X,Y,T)一对模糊集... 详细信息

T-粗糙集是Pawlak粗糙集理论发展过程中的一个重要模型,已成功应用于数据挖掘等诸多领域.FT-粗糙集模型能够在保持数据的完整性下处理连续型数据,是对仅能处理离散型数据的T-粗糙集模型上的发展.文章引入模糊近似空间(X,Y,T)一对模糊集的弱逆和强逆定义,用量化方法研究FT-粗糙集的一些性质,得到模糊技能映射在析取模型、合取模型下分别生成的知识结构;用量化方法与矩阵表示探究FT-粗糙集模糊集值映射在并、交运算下的性质.

关键词： FT-粗糙集模糊近似空间下逆和上逆弱逆和强逆

Preliminary crystallographic studies on two insulin analogues which retain high biological activities after alterations in A chain

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1999年第16期44卷 1480-1483页

作者： Yiding Huang Hui Chen Youmin Feng jiping zhang Shanghai Inst Biochem State Key Lab Mol Biol Shanghai 200031 Peoples R China Inst Biophys State Key Lab Biomacromol Beijing 100101 Peoples R China

Using Fmoc solid phase synthesis and site-directed gene mutagenesis, two insulin analogues, [A13-14GABA,A21Ala] porcine insulin and [A3Thr] human insulin, have been prepared respectively, which retain high biological activities. The results show that non-coded y-amino butyric acid (GABA) could replace the dipeptide, Leu-Tyr, in A13-A14 of insulin and

关键词： [A13-14GABA.A21Ala] porcine insulin [A3Thr] human insulin insulin analogue crystal culture X-ray diffraction.

我国葡萄土壤氮素丰缺指标和适宜施氮量初步研究

在线全文

学校读者我要写书评

暂无评论

中国农业大学学报 2024年第7期29卷 58-67页

作者：孙洪仁朱凯迪王彦张吉萍王尚波王志栋中国农业大学草业科学与技术学院北京100193 山东良土生物科技有限公司山东齐河251100

为建立我国葡萄测土推荐施肥系统,本研究检索了我国葡萄施氮的相关文献,提取土壤有机质、全氮和碱解氮含量,缺氮处理和施氮处理的产量数据,采用作物土壤养分丰缺指标推荐施肥系统研究新方法,研究了我国葡萄土壤氮素丰缺指标与适宜施氮... 详细信息

为建立我国葡萄测土推荐施肥系统,本研究检索了我国葡萄施氮的相关文献,提取土壤有机质、全氮和碱解氮含量,缺氮处理和施氮处理的产量数据,采用作物土壤养分丰缺指标推荐施肥系统研究新方法,研究了我国葡萄土壤氮素丰缺指标与适宜施氮量。结果表明:我国葡萄土壤有机质第1~8级丰缺指标依次为≥75、36~75、17~36、8~17、4~8、2~4、1~2和<1 g/kg,土壤碱解氮第1~8级丰缺指标依次为≥288、158~288、87~158、48~87、26~48、15~26、8~15和<8 mg/kg。当氮肥利用率为30%~50%、葡萄目标产量15.0~60.0 t/hm^(2)时,氮素丰缺级别第1~8级土壤适宜施氮量分别为0、14~90、27~180、41~270、54~360、68~450、81~540和95~630 kg/hm^(2)。本研究初步建立了我国葡萄土壤氮素丰缺指标推荐施肥系统,可为我国葡萄测土施氮提供依据。

关键词：中国葡萄测土施肥碱解氮全氮有机质丰缺指标施肥量

基于Multibody的穿刺手术机器人设计与仿真

在线全文

学校读者我要写书评

暂无评论

实验室研究与探索 2024年第1期43卷 97-101页

作者：邹宇鹏张际平郑杰仁张宗源顾学斌李万哲中国石油大学(华东)机电工程学院山东青岛266580

微创穿刺手术是诊断和治疗肿瘤的重要手段。结合穿刺手术核磁兼容性和穿刺定位精度要求,提出一款2R3T并联柔索驱动核磁兼容穿刺定位手术机器人,可提高穿刺精度,缩短手术时间。设计穿刺手术机器人总体结构,完成正逆运动学分析和轨迹规划... 详细信息

微创穿刺手术是诊断和治疗肿瘤的重要手段。结合穿刺手术核磁兼容性和穿刺定位精度要求,提出一款2R3T并联柔索驱动核磁兼容穿刺定位手术机器人,可提高穿刺精度,缩短手术时间。设计穿刺手术机器人总体结构,完成正逆运动学分析和轨迹规划,借助Multibody构建机器人各模块,建立机器人运动学模型;联合运动学模型与Multibody虚拟样机模型进行仿真。仿真结果表明,运动学模型具有准确性和设计的合理性。Multibody建模仿真过程对机器人运动学和动力学仿真实验教学具有重要意义。

关键词：微创穿刺手术穿刺手术机器人建模仿真

在线全文

学校读者我要写书评

暂无评论

柔索驱动单元的模型辨识与控制器设计

实验室研究与探索 2024年第3期43卷 18-22,45页

作者：邹宇鹏张宗源王梦菲张际平来小靖王新庆中国石油大学(华东)机电工程学院山东青岛266580

针对并联柔索驱动机器人力场模拟应用场景下驱动单元的力伺服控制系统设计,基于Links半物理仿真环境,运用Matlab System Identification工具箱,对柔索驱动单元系统数学模型进行模型辨识,并对系统的不确定性进行辨识。结果表明,考虑柔索... 详细信息

针对并联柔索驱动机器人力场模拟应用场景下驱动单元的力伺服控制系统设计,基于Links半物理仿真环境,运用Matlab System Identification工具箱,对柔索驱动单元系统数学模型进行模型辨识,并对系统的不确定性进行辨识。结果表明,考虑柔索驱动单元的不确定性因素后实际系统模型与理论模型相吻合,且系统理论模型具有较高的可靠性。在可靠的理论模型基础上,对柔索驱动单元进行控制器设计,并验证了模型辨识方法的有效性。基于模型辨识的控制器设计方法可以推广到其他类型系统的模型辨识。

关键词：模型辨识力伺服系统半物理仿真柔索驱动单元