检索结果-南通市图书馆

Invasive Spartina alterniflora accelerates the increase in microbial nitrogen fixation over nitrogen removal in coastal wetlands of china

在线全文

学校读者我要写书评

暂无评论

Eco-Environment & Health 2023年第3期2卷 184-192页

作者： Shuntao Chen Dengzhou gao Xiaofei li Yuhui Niu Cheng liu Dongyao Sun yanling Zheng Hongpo Dong Xia liang Guoyu Yin Xianbiao lin Min liu lijun Hou State Key Laboratory of Estuarine and Coastal Research East China Normal UniversityShanghai 200241China Key Laboratory of Geographic information science of the Ministry of Education College of Geographical SciencesEast China Normal UniversityShanghai 200241China Shandong Key Laboratory of Eco-Environmental science for the Yellow River Delta Binzhou UniversityBinzhou 256600China School of Geography science and Geomatics Engineering Suzhou University of Science and TechnologySuzhou 215009China Frontiers science Center for Deep Ocean Multispheres and Earth System and Key Laboratory of Marine Chemistry Theory and TechnologyMinistry of EducationOcean University of ChinaQingdao 266100China

Salt marsh plants play a vital role in mediating nitrogen(N)biogeochemical cycle in estuarine and coastal ***,the effects of invasive Spartina alterniflora on N fixation and removal,as well as how these two processes balance to determine the N budget,remain ***,simultaneous quantifications of N fixation and removal via^(15)N tracing experiment with native Phragmites australis,invasive ***,and bare flats as well as corresponding functional gene abundance by qPCR were carried out to explore the response of N dynamics to *** *** results showed that N fixation and removal rates ranged from 0.77±0.08 to 16.12±1.13 nmol/(g·h)and from 1.42±0.14 to 16.35±1.10 nmol/(g·h),respectively,and invasive *** generally facilitated the two processes *** on the difference between N removal and fixation rates,net N_(2)fluxes were estimated in the range of-0.39±0.14 to 8.24±2.23 nmol/(g·h).Estimated net N_(2)fluxes in *** stands were lower than those in bare flats and *** stands,indicating that the increase in N removal caused by *** invasion may be more than offset by N fixation *** forest analysis revealed that functional microorganisms were the most important factor associated with the corresponding N transformation ***,our results highlight the importance of N fixation in evaluating N budget of estuarine and coastal wetlands,providing valuable insights into the ecological effect of *** invasion.

关键词： Salt marsh plant N removal N fixation N budget Estuarine and coastal ecosystems

A Prediction Mode of Crop Canopy Nitrogen Hyperspectral Under Mode of "Cornfield Goose Breeding"

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

Journal of Northeast Agricultural university(English Edition) 2019年第2期26卷 75-86页

作者： Wang Shu-wen Ma Xin-yu Guo Chun-fei Guo Yong-gang Zhang yan Zhao Zhong-yuan Wang Chaofan Chen Xiao-liang liu Jun li Rui-xuan li Si-jia Xu kun gao Jia-ying Wang Run-tao college of Electric and information Northeast Agricultural UniversityHarbin 150030China college of information Engineering Lingnan Normal UniversityGuangdong 524048China Tibet Agriculture and Animal Husbandry university Tibet UniversityLinzhi Tibet860000China

The corn canopy taking in before and after grazing term in the production mode of"cornfield goose"was used as the research *** techniques were used to analyze the spectral characteristics of corn canopy leaves in different periods,and a full-band based Principal Component Regression model,Partial Least Squares Regression model and Support Vector Machine regression model were established to propose a fast,convenient and efficient hyperspectral imaging detection *** results showed that the nitrogen value of the grazing area was always lower than that of the control area,during the grazing period,the reflectance of the near-infrared spectrum increased,and the red edge position moved to the *** terms of model establishment,the optimal model was obtained for different grazing *** positive set determining coefficient(Rc 2),the root-mean-square error correction(RMSEC),the prediction set decision coefficient(Rp 2)and the root-mean-square error prediction(RMSEP)were obtained by using SNV-BICA-PCA-PLS in the pre-grazing *** values were 0.9136,0.1750,0.8910 and 0.1052,*** values of Rc 2,RMSEC,Rp 2 and RMSEP were 0.9006,0.0418,0.8508 and 0.1233,respectively,when they were obtained by using MSC-BICA-PCA-MSC in the post-grazing *** research results provided support and help for the future"agriculture and animal husbandry integration"to optimize production management and establish a nitrogen nutrient balance model.

关键词： hyperspectral agriculture and animal husbandry integration nitrogen corn canopy

基于决策融合的SPOT-6影像土地覆被分类研究

在线全文

学校读者我要写书评

暂无评论

地球信息科学学报 2021年第5期23卷 928-937页

作者：李宏达高小红汤敏青海师范大学地理科学学院西宁810008 高原科学与可持续发展研究院西宁810008 青海省自然地理与环境过程重点实验室西宁810008 青藏高原地表过程与生态保育教育部重点实验室西宁810008

多分类器决策融合方法在提高遥感影像分类的准确性和可靠性方面已表现出了巨大潜力,但这一过程中对所有像元多次分类会产生巨大的时间代价,为改善这一问题,本文提出了主分类器的概念。在青海湟水流域确定2个试验区,对7种常用的分类器进... 详细信息

多分类器决策融合方法在提高遥感影像分类的准确性和可靠性方面已表现出了巨大潜力,但这一过程中对所有像元多次分类会产生巨大的时间代价,为改善这一问题,本文提出了主分类器的概念。在青海湟水流域确定2个试验区,对7种常用的分类器进行评估,排除精度较低的3种分类器后,选择支持向量机(Support Vector Machine,SVM)、多层感知机(Multilayer Perceptron,MLP)、随机森林(Random Forest,RF)和梯度提升树(Gradient Boosting Decision Tree,GBDT)4种不同的分类器,建立决策规则共同对SPOT-6影像分类。为提高分类效率,以精度最高的GBDT作为主分类器对影像分类后,仅对结果中可信度不高的像元使用多分类器共同决策。研究结果表明,2个区域内主分类器独立完成分类的像元分别占38.10%和65.26%,错分率为1.57%和2.18%;多分类器共同决策的区域,相比GBDT的分类结果,总体精度分别高出2.49%和3.66%。整体上看,决策融合使2个区域的总体分类精度分别提高了1.18%和1.09%,能够有效减少分类结果中的"椒盐噪声",精度更加均衡。相比现有的决策融合方法,主分类器的使用在保证分类精度的同时有利于分类效率的提高及分类结果保持良好的一致性。

关键词：决策融合多分类器主分类器机器学习 GBDT 土地覆被分类 SPOT-6 湟水流域

Mapping wetland changes in china between 1978 and 2008

在线全文

学校读者我要写书评

暂无评论

Chinese science Bulletin 2012年第22期57卷 2813-2823页

作者： NIU ZhenGuo ZHANG HaiYing WANG XianWei YAO WenBo ZHOU DeMin ZHAO KuiYi ZHAO Hui li NaNa HUANG HuaBing li CongCong yanG Jun liU CaiXia liU Shuang WANG lin li Zhan yanG ZhenZhong QIAO Fei ZHENG YaoMin CHEN yanLei SHENG YongWei gao XiaoHong ZHU WeiHong WANG WenQing WANG Hong WENG Yongling ZHUANG DaFang liU JiYuan LUO ZhiCai CHENG Xiao GUO ZiQi GONG Peng State Key Laboratory of Remote Sensing science Jointly Sponsored by Institute of Remote Sensing ApplicationsChinese Academy of Sciences and Beijing Normal UniversityBeijing 100101China Ministry of Education Key Laboratory for Earth System Modeling Center for Earth System ScienceInstitute for Global Change StudiesTsinghua UniversityBeijing 100084China Department of Resource Environment and Tourism Capital Normal UniversityBeijing 100037China Northeast Institute of Geography and Agricultural Ecology Chinese Academy of SciencesChangchun 130012China Department of Geography and Remote Sensing Beijing Normal UniversityBeijing 100875China college of Forestry Beijing Forestry UniversityBeijing 100083China Department of Environmental science Policy and ManagementUniversity of CaliforniaBerkeley94720USA Department of Geography University of CaliforniaLos Angeles90095USA Department of life and Geographic sciences Qinghai Normal UniversityXining 810008China Department of Geography Yanbian UniversityYanbian 133002China School of Environment and Ecology Xiamen UniversityXiamen 361005China School of Geographical information science Hohai UniversityNanjing 211100China School of Surveying and Mapping Transportation Engineering Southeast UniversityNanjing 210096China Institute of Geographical sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China School of Surveying and Mapping Wuhan UniversityWuhan 430079China

Four wetland maps for all china have been produced,based on Landsat and CBERS-02B remote sensing data between 1978 and 2008 (1978,1990,2000 and 2008).These maps were mainly developed by manual interpretation and validated by substantial field investigation in *** on these maps,we analyzed the 2008 wetland distribution in china and discussed wetland changes and their drivers over the past 30 years.(i) There were about 324097 km 2 of wetlands in 2008,for which inland marshes or swamps were the most common wetland type (35%),with lakes (26%) *** of the wetlands were in Heilongjiang,Inner Mongolia,Qinghai and Tibet,occupying about 55% of the national wetland area.(ii) From 1978 to 2008,china's wetland area continually and significantly decreased,by about 33% based on changes in the wetland *** was in sharp contrast to the increase in artificial wetlands,which increased by about 122%.Inland marshes accounted for the main loss of total wetlands from 1978 to *** 2000 through 2008,riverine and lacustrine wetlands constituted the main wetland *** however,the rate of wetland loss decreased from 5523 to 831 km 2 /a.(iii) The change ratio of lost natural wetlands (including inland and coastal wetlands) to non-wetlands has decreased slightly over the past 30 *** 1978 to 1990,nearly all natural wetlands (98%) lost were transformed into ***,the ratio declined to 86% from 1990 to 2000,and to 77% from 2000 to 2008.(iv) All Chinese provinces were divided into three groups according to patterns of wetland changes,which could relate to the driving forces of such *** was completely different from other provinces,as it was one representative example in which there was a net wetland increase,because of global warming and decreased human activity since *** economic development caused considerable wetland loss in most eastern provinces,and artificial wetlands increased.

关键词：湿地变化中国地图映射地球资源卫星内陆湿地人工湿地全球气候变暖湿地面积

Oxygen-deficient TiO_(2) Yolk-shell Spheres for Enhanced lithium Storage Properties

在线全文

学校读者我要写书评

暂无评论

Energy & Environmental Materials 2022年第1期5卷 238-244页

作者： Zhaoqian li Yuqi Peng Chaofeng liu Xianxi Zhang Xiuling li yang Huang Yingke Ren Denghui Ji Guozhong Cao Key Laboratory of Photovoltaic and Energy Conservation Materials CASInstitute of Solid State PhysicsHefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China college of science Hebei University of Science and TechnologyShijiazhuang 050018China Shandong Provincial Key Laboratory/Collaborative Innovation Center of Chemical Energy Storage&Novel Cell Technology School of Chemistry and Chemical EngineeringLiaocheng UniversityLiaocheng 252000China Department of Materials science and Engineering University of WashingtonSeattle WA 98195USA college of Physics Mechanical and Electronical CollegeShijiazhuang UniversityShijiazhuang City 050035P.R.China college of Physics and information Engineering Hebei Advanced Thin Films LaboratoryHebei Normal UniversityShijiazhuang City 050024P.R.China

Anatase TiO_(2) is a promising anode material for lithium-ion batteries(liBs)owing to its low cost and ***,the intrinsically kinetic limits seriously hindered its lithium-ion storage *** we present that anatase TiO_(2) with rich oxygen vacancies can enhance its lithium-ion storage *** synthesize anatase TiO_(2) with well-retained hierarchical structure by annealing the H_(2)Ti_(5)O_(11)·3H_(2)O yolk-shell spheres precursor in nitrogen *** and XPS data evidence that the oxygen-deficient environment could generate abundant oxygen vacancies in the as-derived anatase TiO_(2),which leads to improved electron conductivity and reduced charge-transfer *** rich oxygen vacancies and high structural integrity of the hierarchical yolk-shell spheres enable the as-derived anatase TiO_(2) yolk-shell spheres with a high specific capacity of 280 mAh g^(-1) at 100 mA g^(-1) and 71%of capacity retention after 5000 cycles at 2 A g^(-1).

关键词： anatase TiO_(2) lithium-ion batteries oxygen vacancies yolk-shell spheres

The relations between the metallicity and orbital parameters of Galactic disk stars

在线全文

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2010年第7期53卷 1348-1356页

作者： li Ji SUN JianAn FU RuiJuan college of Physics science&information Engineering Hebei Normal UniversityShijiazhuang 050016China

The iron abundance gradient in the Galactic disk provides fundamental constraints on the chemical evolution of this important component of the ***,there are still some arguments about the shape of the iron abundance gradient across the Galactic stellar *** provide quantitative constraints on these trends,we constructed an unbiased stellar sample from the common objects of two large *** sample consists of 4004 disk stars in the solar neighborhood with the range of metallicity [Fe/H] from ^-1.0 to ~0.5,including 3855 thin disk stars and 146 thick disk *** range of their mean Galactocentric distances R m is from ~4 to ~11 kpc,and the range of their maximum vertical distance from the Galactic Plane Z max is from 0 to ~3.5 *** relations of the stellar metallicity [Fe/H] with the orbital eccentricity e,and [Fe/H] with R m,as well as [Fe/H] with Z max are investigated in *** results showed that:(1) The orbital eccentricity of disk stars decreases with increasing metallicity,while this trend becomes flat for stars with [Fe/H]>-0.2.(2) For thin disk,there is a clear radial iron gradient of-0.051±0.005 dex/***,this metallicity gradient is discontinuous once we split the sample into the inner(Rm12 dex/kpc is in the outer *** the thick disk,there is no trend of [Fe/H] with R m.(3) The vertical gradient of iron abundance is-0.146 dex/kpc and-0.251 dex/kpc for the thick and thin disks,***,the vertical abundance gradient shows a steeper trend with the evolution of the *** results confirm the collapse mechanism associated with the formation and evolution of the Galactic disk.

关键词： Galaxy Galactic disk star orbital eccentricity abundance gradient

在线全文

学校读者我要写书评

暂无评论

三维形貌测量机器人的轨迹规划技术

中国激光 2019年第2期46卷 118-125页

作者：刘丽马国庆高艺范师杰长春理工大学机电工程学院吉林长春130022

针对带有深孔特征的异型曲面三维形貌的测量需求,提出基于CAD(Computer Aided Design)数模提取信息进行自适应布点的方法和基于法向精度控制的轨迹规划测量方法。通过对机器人的位移-时间、速度-时间与加速度-时间曲线的仿真分析,验证... 详细信息

针对带有深孔特征的异型曲面三维形貌的测量需求,提出基于CAD(Computer Aided Design)数模提取信息进行自适应布点的方法和基于法向精度控制的轨迹规划测量方法。通过对机器人的位移-时间、速度-时间与加速度-时间曲线的仿真分析,验证了运用高阶多项式插值法可得到平滑的轨迹曲线。通过基于法向精度控制的形貌测量实验分析形貌测量过程中TCP(Tool Centror Point)的位置偏差与角度偏差,发现位置偏差小于0.092 mm,角度偏差在0.19°内,证明了所提方法的可行性。

关键词：测量形貌测量机器人轨迹规划

UPLC/Q-TOF MS/MS负离子模式下环氧烷型环烯醚萜苷的结构表征

在线全文

学校读者我要写书评

暂无评论

质谱学报 2019年第2期40卷 197-207页

作者：牟德华胡高爽李存满河北科技大学生物科学与工程学院河北石家庄050018 河北科技大学河北省分析测试研究中心河北石家庄050018

利用四极杆飞行时间串联质谱(Q-TOF MS/MS)研究4个环氧烷型环烯醚萜苷同系组分(胡黄连苷Ⅰ、胡黄连苷Ⅱ、胡麻属苷、梓醇)的质谱裂解行为。在大气压化学电离源负离子(APCI^-)模式下,该类同系组分主要的裂解途径除了常见的母环上取代基... 详细信息

利用四极杆飞行时间串联质谱(Q-TOF MS/MS)研究4个环氧烷型环烯醚萜苷同系组分(胡黄连苷Ⅰ、胡黄连苷Ⅱ、胡麻属苷、梓醇)的质谱裂解行为。在大气压化学电离源负离子(APCI^-)模式下,该类同系组分主要的裂解途径除了常见的母环上取代基的断裂,如中性丢失H_2O、CO_2和葡萄糖基等,生成^(1,6)F^-、^(1,4)F^-等特征碎片离子;另外还存在葡萄糖基环的断裂,生成^(0,4)A_1^-、^(1,4)A_1^-及^(2,4)A_1^-等碎片离子。通过对上述环氧烷型同系组分的质谱裂解行为进行归纳总结,依据其裂解规律,利用UPLC/Q-TOF MS/MS对胡黄连提取物中的环烯醚萜苷类化合物进行表征,共初步鉴定出10个环烯醚萜苷,其中包括8个环氧烷型环烯醚萜苷(胡黄连苷Ⅰ、胡黄连苷Ⅱ、胡黄连苷Ⅲ、胡黄连苷Ⅳ、黄金树苷、梓苷、婆婆纳苷和Piscroside B)和2个环戊烷型环烯醚萜(Boschnaloside和Mussaenosidic acid)。该方法有助于推动胡黄连在物质基础表征、质量控制和临床应用上的开发和利用。

关键词：环氧烷型环烯醚萜苷裂解行为超高效液相色谱-四极杆飞行时间串联质谱(UPLC/Q-TOF MS/MS) 大气压化学电离源负离子模式胡黄连

Influence of Heating Rate on Morphologies and Magnetic Properties ofα-Fe_(2)O_(3)

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2012年第3期29卷 173-175页

作者： li Zi-Yue ZHANG Hui-Min liU li-Hu SUN Hui-Yuan college of Physics science and information Engineering Hebei Normal UniversityShijiazhuang 050024 Key Laboratory of Advanced Films of hebei Province Hebei Normal UniversityShijiazhuang 050024

A variety of hematite microstructures are synthesized through oxalic acid-assisted thermal treatment of iron films sputtered onto glass ***-likeα-Fe_(2)O_(3)nanoslices and honeycomb-likeα-Fe_(2)O_(3)particles of micrometer sizes are obtained after annealing at 500℃but with different rates of heating to the final annealing *** and morphologies of the samples are studied by means of x-ray diffraction,scanningelectron microscopy and atomic force *** structures are believed to be formed during the period of increasing temperature to the final annealing ***-quantum-interference-device magnetometer measurements show room-temperature ferromagnetism in these samples.

关键词： temperature annealing