检索结果-南通市图书馆

Multi-Source Characteristics of Atmospheric Deposition in Nanjing,China,as Controlled by East Asia Monsoons and Urban Activities

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2016年第3期26卷 374-385页

作者： LI Shanquan ZHANG Ganlin yang jinling JIA Nan State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 (China) University of Chinese Academy of Sciences Beijing 100049 (China)

Atmospheric deposition, a major pathway of metals entering into soils, plays an important role in soil environment, especially in urban regions where a large amount of pollutants are emitted into atmosphere through various sources. In order to understand the characteristics of atmospheric deposition in urban area and its relation with natural and anthropogenic sources, a three-year study of atmospheric deposition at three typical sites, industrial zone(IN), urban residential area(RZ) and suburban forested scenic area(FA),was carried out in Nanjing, a metropolitan city in eastern China from 2005 to 2007. The bulk deposition rate and element composition of atmospheric deposition varied spatio-temporally in the urban zones of Nanjing. The concentrations of Cu, Zn, Pb and Ca in the atmospheric deposits were strongly enriched in the whole Nanjing region; however, anthropogenic pollutants in atmospheric deposits were diluted by the input of external mineral dust transported from northwestern China. Source apportionment through principal component analysis(PCA) showed that the background atmospheric deposition at the FA site was the combination of external aerosol and local emission sources. The input of long-range transported Asian dust had an important influence on the urban background deposition, especially in spring when the continental dust from the northwestern China prevailed. Marine aerosol source was observed in summer and autumn, the seasons dominated by summer monsoon in Nanjing. In contrast, the contribution of local anthropogenic emission source was constant regardless of seasons. At the RZ and IN sites, the atmospheric deposition was more significantly affected by the nearby human activities than at the FA site. In addition, different urban activities and both the winter and summer Asian monsoons had substantial impacts on the characteristics of dust deposition in urban Nanjing.

关键词： aerosol anthropogenic pollutants Asian dust metals source apportionment urban environment

Mapping Soil Texture Based on Field Soil Moisture Observations at a High Temporal Resolution in an Oasis Agricultural Area

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2016年第5期26卷 699-708页

作者： yang Renmin LIU Feng ZHANG Ganlin ZHAO Yuguo LI Decheng yang jinling yang Fei yang Fan State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008(China) University of Chinese Academy of Sciences Beijing 100049(China)

Due to the almost homogeneous topography in low relief areas, it is usually difficult to make accurate predictions of soil properties using topographic covariates. In this study, we examined how time series of field soil moisture observations can be used to estimate soil texture in an oasis agricultural area with low relief in the semi-arid region of northwest China. Time series of field-observed soil moisture variations were recorded for 132 h beginning at the end of an irrigation event during which the surface soil was *** correlation between two time-adjacent soil moisture conditions was used to select the factors for fuzzy c-means clustering. In each of the ten generated clusters, soil texture of the soil sample with the maximum fuzzy membership value was taken as the cluster centroid. Finally, a linearly weighted average was used to predict soil texture from the centroids. The results showed that soil moisture increased with the increase of clay and silt contents, but decreased with the increase of sand content. The spatial patterns of soil moisture changed during the entire soil drying phase. We assumed that these changes were mainly caused by spatial heterogeneity of soil texture. A total of 64 independent samples were used to evaluate the prediction accuracy. The root mean square error(RMSE)values of clay, silt and sand were 1.63, 2.81 and 3.71, respectively. The mean relative error(RE) values were 9.57% for clay, 3.77% for silt and 12.83% for sand. It could be concluded that the method used in this study was effective for soil texture mapping in the low-relief oasis agricultural area and could be applicable in other similar irrigation agricultural areas.

关键词： digital soil mapping fuzzy c-means clustering low relief particle-size distribution semi-arid region water content

Direct electrochemistry and electrocatalysis of horseradish peroxidase in MnO_2 nanosheet film

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2008年第8期53卷 1152-1156页

作者： XIAO Han WU jinling CHEN Xu yang WenSheng State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology Beijing 100029 China

A novel material MnO2 nanosheet has been used as the support matrix for the immobilization of horseradish peroxidase (HRP). HRP entrapped in MnO2 nanosheet film exhibits facile direct electron transfer with the electron transfer rate constant of 6.86 s-1. The HRP/MnO2 nanosheet film gives a re- versible redox couple with the apparent formal peak potential (E0′) of -0.315 V (vs. Ag/AgCl) in pH 6.5 phosphate buffer solution (PBS). The formal potential E0′ of HRP shifts linearly with pH with a slope of -53.75 mV·pH-1, denoting that an electron transfer accompanies single-proton transportation. The immobilized HRP shows an electrocatalytic activity to the reduction of H2O2. The response time of the biosensor for H2O2 is less than 3 s, and the detection limit is 0.21 μmol·L-1 based on signal/noise = 3.

关键词：过氧化物酶 HRP 二氧化锰纳米薄片直流电化学过氧化氢

Stoichiometry of base cations and silicon during weathering of a deep soil profile derived from granite

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2023年第5期33卷 800-807页

作者： Yue ZHAO jinling yang Nan JIA Yufang SUN Zhe XU Ganlin ZHANG State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China University of Chinese Academy of Sciences Beijing 100081China State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing 210008China Soil&Environment Analysis Center Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China

Evaluation of the stoichiometry of base cations(BCs,including K^(+),Na^(+),Ca^(2+),and Mg^(2+))and silicon(Si)(BCs:Si)during soil mineral weathering is essential to accurately quantify soil acidification *** aim of this study was to explore the differences and influencing factors of BCs:Si values of different soil genetic horizons in a deep soil profile derived from granite with different extents of mineral *** type was typic acidi-udic *** samples were collected from Guangzhou,China,which is located in a subtropical *** ensure that the BCs and Si originated from the mineral weathering process,soil exchangeable BCs were washed with an elution *** BCs:Si values during weathering were obtained through a simulated acid rain leaching experiment using the batch *** showed that soil physical,chemical,and mineralogical properties varied from the surface horizon to saprolite in the soil *** BCs:Si values of soil genetic horizons during weathering were 0.3–*** BCs:Si value was 1.7 in the surface horizon(A),1.1–3.7 in the argillic horizon(Bt),and 0.3–0.4 in the cambic(Bw)and transition(BC)horizons,as well as in horizon C(saprolite).The general pattern of BCs:Si values in the different horizons was as follows:Bt>A>Bw,BC,and *** BCs:Si values were influenced by weathering intensity,they did not correlate with the chemical index of alteration(CIA).The release amounts of Si and BCs are the joined impact of soil mineral composition and physical and chemical properties.A comprehensive analysis showed that the BCs:Si values of the soil derived from granite in this study were a combined result of the following factors:soil clay,feldspar,kaolinite,organic matter,pH,and *** main controlling factors of BCs:Si in soils of different parent material types require extensive *** wide variance of BCs:Si values in the deep soil profile indicated that H+consumed by soil mineral weathering was very dissimilar i

关键词： mineral weathering soil acidification rate soil evolution soil genesis soil geochemistry weathered sequence

Vertical distribution and storage of soil organic and inorganic carbon in a typical inland river basin,Northwest China

在线全文

学校读者我要写书评

暂无评论

Journal of Arid Land 2018年第2期10卷 183-201页

作者： yang Fan HUANG Laiming yang Renmin yang Fei LI Decheng ZHAO Yuguo yang jinling LIU Feng ZHANG Ganlin State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China

Knowledge of soil carbon（C） distribution and its relationship with the environment can improve our understanding of its biogeochemical cycling and help to establish sound regional models of C cycling. However, such knowledge is limited in environments with complex landscape configurations. In this study, we investigated the vertical distribution and storage of soil organic carbon（SOC） and soil inorganic carbon（SIC） in the 10 representative landscapes（alpine meadow, subalpine shrub and meadow, mountain grassland, mountain forest, typical steppe, desert steppe, Hexi Corridor oases cropland, Ruoshui River delta desert, Alxa Gobi desert, and sandy desert） with contrasting bioclimatic regimes in the Heihe River Basin, Northwest China. We also measured the 87 Sr/86 Sr ratio in soil carbonate to understand the sources of SIC because the ratio can be used as a proxy in calculating the contribution of pedogenic inorganic carbon（PIC） to total SIC. Our results showed that SOC contents generally decreased with increasing soil depth in all landscapes, while SIC contents exhibited more complicated variations along soil profiles in relation to pedogenic processes and parent materials at the various landscapes. There were significant differences of C stocks in the top meter among different landscapes, with SOC storage ranging from 0.82 kg C/m^2 in sandy desert to 50.48 kg C/m^2 in mountain forest and SIC storage ranging from 0.19 kg C/m^2 in alpine meadow to 21.91 kg C/m^2 in desert steppe. SIC contributed more than 75% of total C pool when SOC storage was lower than 10 kg C/m^2, and the proportion of PIC to SIC was greater than 70% as calculated from Sr isotopic ratio, suggesting the critical role of PIC in the C budget of this region. The considerable variations of SOC and SIC in different landscapes were attributed to different pedogenic environments resulted from contrasting climatic regimes, parent materials and vegetation types. This study provides an evidence for a general t

关键词： Heihe River Basin arid ecosystem soil landscape pedogenesis pedogenic carbonate SOC CaCO3

Quantitative Relationship Between Land Use and Phosphorus Discharge in Subtropical Hilly Regions of China

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2003年第1期13卷 67-74页

作者： yang jinling and ZHANG GANLINInstitute of Soil Science, the Chinese Academy of Sciences, Nanjing 210008 (China) Institute of Soil Science the Chinese Academy of Sciences Nanjing 210008

The increase of phosphorus concentration is a crucial factor causing the eutrophication of water body,while land use has an important impact on agricultural non-point sources (NPS) phosphorus discharge. Sevensites controlling the water in four sub-watersheds and the main exit of the Meicun Watershed of XuanchengCounty, Anhui Province, were investigated by dynamic monitoring of stream water and nutrient discharge,integrating interpretation of aerial image and GIS analysis to find out how the land use affects phosphorusloss with stream water in typical agriculture-forest watershed in subtropical China. These monitored sitesare different in structure of land use. Phosphorus concentration of the stream water was analyzed everyweek and at the next day of rainfall. The velocity of flow was measured by kinemometer to calculatethe runoff flux and phosphorus discharge. The results showed that the runoff flux and the discharges ofdissolved phosphorus (DP), particle-associated phosphorus (PAP) and total phosphorus (TP) had significantexponential relationships with the area percentages of forest, pond and paddy field. There existed a significantlinear relationship between the TP and PAP concentrations in stream water and the area percentages of forest,pond and paddy field, and the discharge of PAP was also significantly linearly correlated with the dischargeof suspended soil particles. There was a logarithmic linear relationship between DP and PAP discharges. Thestudy indicated that the adjustment of land use patterns and construction of ecologically sound landscapewould be an important measure to reduce the runoff discharge of phosphorus. The results would be veryuseful in building the best management practices (BMPs) of agricultural watershed in subtropics.

关键词： land use phosphorus runoff watershed

A mechanically coupled MEMS filter with high-Q width extensional mode resonators

在线全文

学校读者我要写书评

暂无评论

Journal of Semiconductors 2024年第8期45卷 41-48页

作者： Wei Wang Wenli Liu Junyuan Zhao Bo Niu Zeyu Wu Yinfang Zhu jinling yang Fuhua yang Institute of Semiconductors Chinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

This work presents a novel radio frequency(RF)narrowband Si micro-electro-mechanical systems(MEMS)filter based on capacitively transduced slotted width extensional mode(WEM)*** flexibility of the plate leads to multiple modes near the target *** high Q-factor resonators of around 100000 enable narrow bandwidth filters with small size and simplified *** 1-wavelength and 2-wavelength WEMs were first developed as a pair of coupled modes to form a *** reduce bandwidth,two plates are coupled with aλ-length coupling *** 79.69 MHz coupled plate filter(CPF)achieved a narrow bandwidth of 8.8 kHz,corresponding to a tiny 0.011%.The CPF exhibits an impressive 34.84 dB stopband rejection and 7.82 dB insertion loss with near-zero passband *** summary,the RF MEMS filter presented in this work shows promising potential for application in RF transceiver front-ends.

关键词： MEMS narrowband filter mechanically coupling quality factor width extensional mode

Modeling spatio-temporal distribution of soil moisture by deep learning-based cellular automata model

在线全文

学校读者我要写书评

暂无评论

Journal of Arid Land 2016年第5期8卷 734-748页

作者： SONG Xiaodong ZHANG Ganlin LIU Feng LI Decheng ZHAO Yuguo yang jinling State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of Sciences

Soil moisture content （SMC） is a key hydrological parameter in agriculture,meteorology and climate change,and understanding of spatio-temporal distributions of SMC in farmlands is important to address the precise irrigation ***,the hybrid interaction of static and dynamic environmental parameters makes it particularly difficult to accurately and reliably model the distribution of *** present,deep learning wins numerous contests in machine learning and hence deep belief network （DBN） ,a breakthrough in deep learning is trained to extract the transition functions for the simulation of the cell state *** this study,we used a novel macroscopic cellular automata （MCA） model by combining DBN to predict the SMC over an irrigated corn field （an area of 22 km^2） in the Zhangye oasis,Northwest *** and dynamic environmental variables were prepared with regard to the complex hydrological *** widely used neural network,multi-layer perceptron （MLP） ,was utilized for comparison to *** hybrid models （MLP-MCA and DBN-MCA） were calibrated and validated on SMC data within four months,*** to September 2012,which were automatically observed by a wireless sensor network （WSN） .Compared with MLP-MCA,the DBN-MCA model led to a decrease in root mean squared error （RMSE） by 18%.Thus,the differences of prediction errors increased due to the propagating errors of variables,difficulties of knowing soil properties and recording irrigation amount in *** sequential Gaussian simulation （s Gs） was performed to assess the uncertainty of soil moisture *** with a threshold of SMC for each grid cell,the local uncertainty of simulated results in the post processing suggested that the probability of SMC less than 25% will be difference in different areas at different time *** current results showed that the DBN-MCA model performs better than the MLP-MCA model,and the DBN-MCA model provides a powerful tool for predicti

关键词： soil moisture soil moisture sensor network macroscopic cellular automata (MCA) deep belief network (DBN) multi-layer perceptron (MLP) uncertainty assessment hydropedology

Mapping Soil Organic Carbon Using Local Terrain Attributes： AComparison of Different Polynomial Models

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2017年第4期27卷 681-693页

作者： SONG Xiaodong LIU Feng ZHANG Ganlin LI Decheng ZHAO Yuguo yang jinling State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China

Local terrain attributes,which are derived directly from the digital elevation model,have been widely applied in digital soil *** study aimed to evaluate the mapping accuracy of soil organic carbon(SOC) concentration in 2 zones of the Heihe River in China,by combining prediction methods with local terrain attributes derived from different polynomial *** prediction accuracy was used as a benchmark for those who may be more concerned with how accurately the variability of soil properties is modeled in practice,rather than how morphometric variables and their geomorphologic interpretations are understood and *** this study,2 neighborhood types(square and circular) and 6 representative algorithms(Evans-Young,Horn,Zevenbergen-Thorne,Shary,Shi,and Florinsky algorithms) were *** general,35 combinations of first-and second-order derivatives were produced as candidate predictors for soil mapping using two mapping methods(i.e.,kriging with an external drift and geographically weighted regression).The results showed that appropriate local terrain attribute algorithms could better capture the spatial variation of SOC concentration in a region where soil properties are strongly influenced by the *** the different combinations of firstand second-order derivatives used,there was a best combination with a more accurate *** different prediction methods,the relative improvement in the two zones varied between 0.30% and 9.68%.The SOC maps resulting from the higher-order algorithms(Zevenbergen-Thorne and Florinsky) yielded less interpolation ***,it was concluded that the performance of predictive methods,which incorporated auxiliary variables,could be improved by attempting different terrain analysis algorithms.

关键词： cross-validation digital soil mapping geographically weighted regression kriging with an external drift mapping accuracy