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Portable Software Environment for Ultrahigh-Resolution ELM Development on GPUs
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作者 Dali Wang Peter Schwartz +5 位作者 Fengming Yuan Franklin Eaglebarge Danial Riccuito Peter Thornton Chris Layton Qinglei Cao 《Journal of Computer and Communications》 2025年第2期28-36,共9页
This paper presents our endeavors in developing the large-scale, ultra-high-resolution E3SM Land Model (uELM), specifically designed for exascale computers furnished with accelerators such as Nvidia GPUs. The uELM is ... This paper presents our endeavors in developing the large-scale, ultra-high-resolution E3SM Land Model (uELM), specifically designed for exascale computers furnished with accelerators such as Nvidia GPUs. The uELM is a sophisticated code that substantially relies on High-Performance Computing (HPC) environments, necessitating particular machine and software configurations. To facilitate community-based uELM developments employing GPUs, we have created a portable, standalone software environment preconfigured with uELM input datasets, simulation cases, and source code. This environment, utilizing Docker, encompasses all essential code, libraries, and system software for uELM development on GPUs. It also features a functional unit test framework and an offline model testbed for comprehensive numerical experiments. From a technical perspective, the paper discusses GPU-ready container generations, uELM code management, and input data distribution across computational platforms. Lastly, the paper demonstrates the use of environment for functional unit testing, end-to-end simulation on CPUs and GPUs, and collaborative code development. 展开更多
关键词 E3SM Land Model Ultrahigh-Resolution ELM Portable Software Environment GPU-Ready Environment
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Soil Environment and Pollution Remediation 被引量:7
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作者 ZHOU Dongmei SONG Xin +1 位作者 ZHAO Fangjie Baohua GU 《Pedosphere》 SCIE CAS CSCD 2017年第3期387-388,共2页
The global soil environment has been under increasing pressure due to rapid industrialization and urbanization,along with intensive farming on arable land.In particular,the soil environmental quality in China is deter... The global soil environment has been under increasing pressure due to rapid industrialization and urbanization,along with intensive farming on arable land.In particular,the soil environmental quality in China is deteriorating in a rapid pace according to the'National Soil Pollution Survey'by the Ministry of Environmental Protection and the Ministry of Land and Resources of China(released on April 17,2014). 展开更多
关键词 土壤环境质量 污染修复 生态系统功能 环境保护 城市化进程 国土资源部 污染状况 人类健康
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Considerations in Applying the General Equilibrium Approach to Environmental Health Assessment 被引量:2
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作者 YUE WAN HONG-WEI YANG AND TOSHIHIKO MASUI 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2005年第5期356-361,共6页
There are currently two commonly used approaches to assessing economic impacts of health damage resulting from environmental pollution: human capital approach (HCA) and willingness-to-pay (WTP). WTP can be furthe... There are currently two commonly used approaches to assessing economic impacts of health damage resulting from environmental pollution: human capital approach (HCA) and willingness-to-pay (WTP). WTP can be further divided into averted expenditure approach (AEA), hedonlc wage approach (HWA), contingent valuation approach (CVA) and hedonlc price approach (HPA). A general review of the principles behind these approaches by the authors indicates that these methods are incapable of unveiling the mechanism of health impact from the point of view of national economy. On a basis of economic system, the shocks brought about by health effects of environmental pollution change the labor supply and medical expenditure, which in turn affects the level of production activity in each sector and the total final consumption pattern of the society. The general equilibrium approach within the framework of macroeconomic theory is able to estimate the health impact on national economy comprehensively and objectively. Its mechanism and applicability are discussed in detail by the authors. 展开更多
关键词 Human capital approach WILLINGNESS-TO-PAY General equilibrium approach
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Using Longwave Infrared Hyperspectral Imaging for a Quantitative Atmospheric Tracer Monitoring in Outdoor Environments 被引量:1
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作者 Eitan Hirsch Eyal Agassi Alon Manor 《International Journal of Geosciences》 2021年第3期233-252,共20页
Quantitative real-time retrieval of concentration-lengths (CL) through gaseous plumes is an important tool for environmental monitoring, enabling remote monitoring of emissions from industrial facilities and risk asse... Quantitative real-time retrieval of concentration-lengths (CL) through gaseous plumes is an important tool for environmental monitoring, enabling remote monitoring of emissions from industrial facilities and risk assessment in scenarios of toxic gas releases. The adoption of LWIR (Long Wave InfraRed) hyperspectral imaging as a leading technique for remote gas plume detection paved the way for an introduction of a precise CL estimation and two-dimensional (2D) mapping. A novel methodology for evaluating and characterizing the performance of a retrieval algorithm is presented. The algorithm utilizes state-of-the-art retrieved hyperspectral 2D mapping and is applied on a series of localized atmospheric tracer gas (SF<sub><span style="font-family:Verdana;">6</span></sub><span style="font-family:Verdana;">) releases in monitored environmental conditions. The retrieved CL distributions are compared to a numeric atmospheric T&D (Transport and Diffusion) model. Satisfactory agreement between retrieved and simulated CL prediction is manifested, and the uncertainty involved is quantified. Possible sources for the remained discrepancies between retrieved and simulated CL values are characterized, and methods to minimize them are discussed.</span> 展开更多
关键词 HYPERSPECTRAL INFRARED Gaseous Plumes Concentration-Length Quantification Atmospheric Transport and Diffusion (T&D) Model
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Modeling of Precipitation over Africa:Progress,Challenges,and Prospects
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作者 A.A.AKINSANOLA C.N.WENHAJI +21 位作者 R.BARIMALALA P.-A.MONERIE R.D.DIXON A.T.TAMOFFO M.O.ADENIYI V.ONGOMA I.DIALLO M.GUDOSHAVA C.M.WAINWRIGHT R.JAMES K.C.SILVERIO A.FAYE S.S.NANGOMBE M.W.POKAM D.A.VONDOU N.C.G.HART I.PINTO M.KILAVI S.HAGOS E.N.RAJAGOPAL R.K.KOLLI S.JOSEPH 《Advances in Atmospheric Sciences》 2026年第1期59-86,共28页
In recent years,there has been an increasing need for climate information across diverse sectors of society.This demand has arisen from the necessity to adapt to and mitigate the impacts of climate variability and cha... In recent years,there has been an increasing need for climate information across diverse sectors of society.This demand has arisen from the necessity to adapt to and mitigate the impacts of climate variability and change.Likewise,this period has seen a significant increase in our understanding of the physical processes and mechanisms that drive precipitation and its variability across different regions of Africa.By leveraging a large volume of climate model outputs,numerous studies have investigated the model representation of African precipitation as well as underlying physical processes.These studies have assessed whether the physical processes are well depicted and whether the models are fit for informing mitigation and adaptation strategies.This paper provides a review of the progress in precipitation simulation overAfrica in state-of-the-science climate models and discusses the major issues and challenges that remain. 展开更多
关键词 RAINFALL MONSOON climate modeling CORDEX CMIP6 convection-permitting models
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Biological transformation,kinetics and dose-response assessments of bound musk ketone hemoglobin adducts in rainbow trout as biomarkers of environmental exposure
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作者 M A Mottaleb J H Zimmerman T W Moy 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2008年第7期878-884,共7页
Low levels (ng/g) of musk ketone (MK),used as a fragrance additive in the formulation of personal care products,are frequently detected in the water and other environment.Thus,aquatic organisms can be continuously exp... Low levels (ng/g) of musk ketone (MK),used as a fragrance additive in the formulation of personal care products,are frequently detected in the water and other environment.Thus,aquatic organisms can be continuously exposed to MK.In this study,kinetics and dose-response assessments of 2-amino-MK (AMK) metabolite,bound to cysteine-hemoglobin (Hb) in rainbow trout,formed by enzymatic nitro-reduction of MK have been demonstrated.Trout were exposed to a single exposure of 0.010,0.030,0.10,and 0.30 mg MK/g fish.Tw... 展开更多
关键词 BIOTRANSFORMATION KINETICS hemoglobin adducts DOSE-RESPONSE nitro musks BIOMARKER fish
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Hybrid energy module for remote environmental observations, experiments, and communications
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作者 Misha B.KRASSOVSKI Jeffery S.RIGGS +2 位作者 Chris TAVINO Stan D.WULLSCHLEGER Susan L.HEINZ 《Advances in Polar Science》 CSCD 2020年第3期156-166,共11页
Increased concerns about climate change have led to a significant expansion of monitoring, observational, and experimental sites in remote areas of the world. Meanwhile, advances in technology and availability of low-... Increased concerns about climate change have led to a significant expansion of monitoring, observational, and experimental sites in remote areas of the world. Meanwhile, advances in technology and availability of low-power equipment have allowed increasingly sophisticated measurements with a wide variety of instruments. However, the deployment and use of these technologies in remote locations is often restricted not only by harsh environmental conditions, but also by the availability of electrical power and communication options. In some cases, research stations and military installations can provide power for scientific equipment, data acquisition, storage, and transmission. Clustering of research sites near existing infrastructure has had the unintended consequence of limiting a spatial understanding of large geographic regions. Fortunately, the modern market offers many power and communication solutions, but most of them are oriented toward large industrial applications. Use of those solutions to power a research site is limited because of their cost and need for significant modification for the specific research purposes. Each study has its own unique power requirements and needs for proper instrumentation. A power and communication solution for a vast majority of implementations with or without modification would be of considerable benefit. This article describes design of a universal, scalable hybrid energy module for the Next-Generation Ecosystem Experiments Arctic project(https://ngee-arctic.ornl.gov/). Two modules were built, and the authors describe their implementation and findings over a 2-year period at a remote field site on the Seward Peninsula in western Alaska, USA. 展开更多
关键词 solar energy wind energy COMMUNICATIONS power sources alternative energy NGEE Arctic
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Technical, Economic and Environmental Evaluation on Mechanical Rice Straw Gathering Method
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作者 Nguyen Thanh Nghi Nguyen Duc Canh +2 位作者 Hau Duc Hoa Nguyen Van Hung Martin Gummert 《Journal of Environmental Science and Engineering(B)》 2015年第11期614-619,共6页
Rice straw is a rice by-product, which is currently mostly wasted in Vietnam, in particular in the Mekong delta. At present, the cost of straw gathering is increasing because of the increased use of combine harvesters... Rice straw is a rice by-product, which is currently mostly wasted in Vietnam, in particular in the Mekong delta. At present, the cost of straw gathering is increasing because of the increased use of combine harvesters. High labor cost and lack of labor makes manual collection unfeasible. Farmers therefore often just burn it, which causes pollution, increased greenhouse gas emissions and loss of opportunities to value add. An economic and environmental evaluation and technical field testing of a straw baler with 4 ha/day capacity was therefore conducted in Long An province. During the field testing data on the gathering capacity, fuel consumption, labor requirement and other cost items were collected. The test results showed that the baling cost is US$19.0 per ton of rice straw, the pay-back period of 2. 1 years and the internal rate of return of 38%. In addition to the baling cost, the transportation cost varies from US$24 for a distance of 100 km to US$32 for 150 km. The benefits of the machine are not only economical but also include the reduction of field burning. 展开更多
关键词 Rice straw gathering technical and economic evaluation environmental benefits.
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Concealed Environmental Threat in the Coastal Region Requires Persistent Attention:The Panglao Island,Philippines Example
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作者 Daniel Edison Husana Tomohiko Kikuchi 《Journal of Environmental Protection》 2013年第10期1149-1156,共8页
Panglao is a small island in the central part of the Philippines and well-known for its world-class beaches and coral reefs. These attract millions of tourists each year thus providing business opportunities and emplo... Panglao is a small island in the central part of the Philippines and well-known for its world-class beaches and coral reefs. These attract millions of tourists each year thus providing business opportunities and employment, a significant source of revenue for the local economy. Moreover, this island lies in a region with high biodiversity. However, the escalating activity is so alarming that the negative effect to the local environment is very much prevalent but not easily perceivable. Analysis and measurement of physico-chemical parameters of the groundwater revealed high levels of human-induced contaminants. This subterranean pollution was attributable to the leakage of septic tanks, artificial application of disinfectants as well as infiltration of saltwater from the ocean due to over-extraction of groundwater in order to meet the increasing demand for water. The community within the area was oblivious because human impacts to the environment appear to be virtually absent. These findings clearly suggest the concealed vulnerability of the groundwater resources from human activities. Higher standard for the coastal development plan, strong implementation of environmental policy and immediate government action is deemed necessary. 展开更多
关键词 Hidden Environmental Threat GROUNDWATER Coastal Region Panglao Island Philippines
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Building Information Modeling for Environmental Impact Assessment in Early Design Phases: A Literature Review
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作者 Marie-France Stendahl Marie-Claude Dubois +1 位作者 Daniel Forgues Eilif Hjelseth 《Open Journal of Applied Sciences》 2022年第1期59-81,共23页
The building sector is the largest consumer of energy in industrial countries. Saving energy in new buildings or building renovations can thus lead to significant global environmental impacts. In this endeavor, buildi... The building sector is the largest consumer of energy in industrial countries. Saving energy in new buildings or building renovations can thus lead to significant global environmental impacts. In this endeavor, building information <span>modeling (BIM) and building energy modeling (BEM) are two important to</span>ols to make the transition to net-zero energy buildings (NZEB). So far, little attention has been devoted, in the literature, to discuss the connection between BIM, BEM, and Life-cycle assessment (LCA), which is the main topic of this article. A literature review of 157 journal articles and conference proceedings published between 1990 and 2020 is presented. This review outlines knowledge gaps concerning BIM, BEM, and environmental impact assessment. It suggests that defining the process with the right technology (at the right time) would result in a more integrated design process (IDP) and bridge current gaps. The most efficient way to improve process and technology is related to the competences of the architects, engineers and constructors (AEC). The review also indicates that the IDP in the early design phases (EDP) is in need of improvement for architects and engineers, where a better connection between design phases, specific levels of development (LOD) and BIM tools is needed. <span>Competences, process and technology are the three main themes addressed in the review. Their relation to design phases and LOD is discussed. The aim </span>is to propose possible solutions to the current hinders in BIM-to-BEM (BIM2BEM) and BIM-for-LCA (BIM4LCA) integration. 展开更多
关键词 Building Information Modeling (BIM) Building Energy Modeling (BEM) Life Cycle Assessment (LCA) Simulations Energy CARBON Design Process Design Phases Level of Development
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Patterns of plant species richness and diversity across treelines in Himachal Pradesh,Western Himalaya
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作者 Rohit SHARMA Sanjay Kr.UNIYAL Shalinder KAUR 《Journal of Mountain Science》 2025年第5期1586-1599,共14页
Treelines are ecologically unique,fragile,and rich in natural resources.They harbour high species diversity and at the same time are under threat due to anthropogenic activities.Recognizing this,the present study has ... Treelines are ecologically unique,fragile,and rich in natural resources.They harbour high species diversity and at the same time are under threat due to anthropogenic activities.Recognizing this,the present study has been framed to document the patterns of species richness and diversity in the state of Himachal Pradesh,western Himalaya.A total of six treeline sites(three disturbed and three undisturbed)were identified for vegetation sampling.Trees,shrubs,and herbs were sampled at each site using nested plots of 10 m^(2),5 m^(2),and 1 m^(2),respectively.The study exhibits the rich diversity of treeline communities,the patterns of which varied between treeline sites.Altogether,221 species of vascular plants belonging to 47 families and 140 genera were recorded from the area.Amongst families,Asteraceae was the dominant family followed by Apiaceae and Ranunculaceae.The study also revealed the presence of threatened species like Aconitum heterophyllum,Angelica glauca,Bergenia stracheyi,Dactylorhiza hatagirea,Picrorhiza kurroa,and Trillium govanianum etc.at treeline.Moreover,species composition revealed high densities of Betula utilis followed by the under canopy of Rhododendron campanulatum and R.anthopogon at treeline sites.Overall,species richness of herbs,shrubs,and trees were higher at undisturbed site as compared to disturbed one.The diversity indices of herbs and shrubs varied significantly between treeline sites while that of trees was non-significant.At the same time,soil properties showed distinct patterns wherein pH and available nitrogen significantly varied between treeline sites.Present study provides detailed insights into the floristic and ecological aspects of treeline communities from the unexplored ecoregion of western Himalaya.The treelines in the area are anthropogenically depressed and continued land-use activities might result in habitat fragmentation and displacement of plant communities in the near future. 展开更多
关键词 Alpine treeline DISTURBANCE Floristic diversity HIMALAYA Soil Vegetation patterns
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Half-Covered'Glitter-Cake'AM@SE Composite:A Novel Electrode Design for High Energy Density All-Solid-State Batteries
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作者 Min Ji Kim Jin-Sung Park +8 位作者 Jin Woong Lee Sung Eun Wang Dowoong Yoon Jong Deok Lee Jung Hyun Kim Taeseup Song Ju Li Yun Chan Kang Dae Soo Jung 《Nano-Micro Letters》 2025年第5期463-478,共16页
All-solid-state batteries(ASSBs)are pursued due to their potential for better safety and high energy density.However,the energy density of the cathode for ASSBs does not seem to be satisfactory due to the low utilizat... All-solid-state batteries(ASSBs)are pursued due to their potential for better safety and high energy density.However,the energy density of the cathode for ASSBs does not seem to be satisfactory due to the low utilization of active materials(AMs)at high loading.With small amount of solid electrolyte(SE)powder in the cathode,poor electrochemical performance is often observed due to contact loss and non-homogeneous distribution of AMs and SEs,leading to high tortuosity and limitation of lithium and electron transport pathways.Here,we propose a novel cathode design that can achieve high volumetric energy density of 1258 Wh L^(-1)at high AM content of 85 wt%by synergizing the merits of AM@SE core–shell composite particles with conformally coated thin SE shell prepared from mechanofusion process and small SE particles.The core–shell structure with an intimate and thin SE shell guarantees high ionic conduction pathway while unharming the electronic conduction.In addition,small SE particles play the role of a filler that reduces the packing porosity in the cathode composite electrode as well as between the cathode and the SE separator layer.The systematic demonstration of the optimization process may provide understanding and guidance on the design of electrodes for ASSBs with high electrode density,capacity,and ultimately energy density. 展开更多
关键词 All-solid-state batteries Cathodes Sulfide-based solid electrolytes Interfaces Mechanofusion
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Source apportionment of PM_(2.5) using dispersion normalized positive matrix factorization(DN-PMF)in Beijing and Baoding,China
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作者 Ilhan Ryoo Taeyeon Kim +6 位作者 Jiwon Ryu Yeonseung Cheong Kwang-joo Moon Kwon-ho Jeon Philip K.Hopke Seung-Muk Yi Jieun Park 《Journal of Environmental Sciences》 2025年第9期395-408,共14页
Fine particulatematter(PM_(2.5))samples were collected in two neighboring cities,Beijing and Baoding,China.High-concentration events of PM_(2.5) in which the average mass concentration exceeded 75μg/m^(3) were freque... Fine particulatematter(PM_(2.5))samples were collected in two neighboring cities,Beijing and Baoding,China.High-concentration events of PM_(2.5) in which the average mass concentration exceeded 75μg/m^(3) were frequently observed during the heating season.Dispersion Normalized Positive Matrix Factorization was applied for the source apportionment of PM_(2.5) as minimize the dilution effects of meteorology and better reflect the source strengths in these two cities.Secondary nitrate had the highest contribution for Beijing(37.3%),and residential heating/biomass burning was the largest for Baoding(27.1%).Secondary nitrate,mobile,biomass burning,district heating,oil combustion,aged sea salt sources showed significant differences between the heating and non-heating seasons in Beijing for same period(2019.01.10–2019.08.22)(Mann-Whitney Rank Sum Test P<0.05).In case of Baoding,soil,residential heating/biomass burning,incinerator,coal combustion,oil combustion sources showed significant differences.The results of Pearson correlation analysis for the common sources between the two cities showed that long-range transported sources and some sources with seasonal patterns such as oil combustion and soil had high correlation coefficients.Conditional Bivariate Probability Function(CBPF)was used to identify the inflow directions for the sources,and joint-PSCF(Potential Source Contribution Function)was performed to determine the common potential source areas for sources affecting both cities.These models facilitated a more precise verification of city-specific influences on PM_(2.5) sources.The results of this study will aid in prioritizing air pollution mitigation strategies during the heating season and strengthening air quality management to reduce the impact of downwind neighboring cities. 展开更多
关键词 Source apportionment Dispersion normalized positive matrix factorization Adjacent cities Inter-city impact Source location Heating season Air quality management
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Sustainable aviation fuels from biomass and biowaste via bio-and chemo-catalytic conversion:Catalysis,process challenges,and opportunities
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作者 Junyan Zhang Matthew S.Webber +22 位作者 Yunqiao Pu Zhenglong Li Xianzhi Meng Michael L.Stone Bingqing Wei Xueqi Wang Sainan Yuan Bruno Klein Bhogeswararao Seemala Charles E.Wyman Karthikeyan K.Ramasamy Mike Thorson Matthew H.Langholtz Joshua S.Heyne Aibolat Koishybay Shiba Adhikari Sufeng Cao Andrew D.Sutton Gerald A.Tuskan Yuriy Román-Leshkov Arthur J.Ragauskas Tao Ling Brian H.Davison 《Green Energy & Environment》 2025年第6期1210-1234,共25页
Sustainable aviation fuel(SAF)production from biomass and biowaste streams is an attractive option for decarbonizing the aviation sector,one of the most-difficult-to-electrify transportation sectors.Despite ongoing co... Sustainable aviation fuel(SAF)production from biomass and biowaste streams is an attractive option for decarbonizing the aviation sector,one of the most-difficult-to-electrify transportation sectors.Despite ongoing commercialization efforts using ASTM-certified pathways(e.g.,lipid conversion,Fischer-Tropsch synthesis),production capacities are still inadequate due to limited feedstock supply and high production costs.New conversion technologies that utilize lignocellulosic feedstocks are needed to meet these challenges and satisfy the rapidly growing market.Combining bio-and chemo-catalytic approaches can leverage advantages from both methods,i.e.,high product selectivity via biological conversion,and the capability to build C-C chains more efficiently via chemical catalysis.Herein,conversion routes,catalysis,and processes for such pathways are discussed,while key challenges and meaningful R&D opportunities are identified to guide future research activities in the space.Bio-and chemo-catalytic conversion primarily utilize the carbohydrate fraction of lignocellulose,leaving lignin as a waste product.This makes lignin conversion to SAF critical in order to utilize whole biomass,thereby lowering overall production costs while maximizing carbon efficiencies.Thus,lignin valorization strategies are also reviewed herein with vital research areas identified,such as facile lignin depolymerization approaches,highly integrated conversion systems,novel process configurations,and catalysts for the selective cleavage of aryl C-O bonds.The potential efficiency improvements available via integrated conversion steps,such as combined biological and chemo-catalytic routes,along with the use of different parallel pathways,are identified as key to producing all components of a cost-effective,100%SAF. 展开更多
关键词 LIGNOCELLULOSE Bio-and chemo-catalytic conversion Lignin valorization Sustainable aviation fuel CATALYSIS
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北京大气重污染过程PM_(10)中水溶性盐的研究 被引量:28
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作者 张凯 王跃思 +3 位作者 温天雪 胡波 刘广仁 Meslmani Yousef 《中国环境科学》 EI CAS CSCD 北大核心 2006年第4期385-389,共5页
利用大气颗粒物快速捕集及化学成分在线分析系统,观测了2004年秋季北京出现的一次长时间严重污染天气过程中PM10的水溶性无机盐浓度的变化.结果表明,PM10中总水溶性无机盐浓度在这次重污染过程中升高了4.7倍.硝酸盐、硫酸盐、铵盐的浓... 利用大气颗粒物快速捕集及化学成分在线分析系统,观测了2004年秋季北京出现的一次长时间严重污染天气过程中PM10的水溶性无机盐浓度的变化.结果表明,PM10中总水溶性无机盐浓度在这次重污染过程中升高了4.7倍.硝酸盐、硫酸盐、铵盐的浓度分别升高7.9,4.1,5.4倍,这3种无机盐的日变化在污染期和非污染期有明显差异.污染期SO2、NOx向SO42-、NO3-转化率明显高于非污染期. 展开更多
关键词 重污染 PM10 硝酸盐 硫酸盐 铵盐
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应用集成BP神经网络进行田间土壤空间变异研究 被引量:34
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作者 沈掌泉 施洁斌 +1 位作者 王珂 John S.Bailey 《农业工程学报》 EI CAS CSCD 北大核心 2004年第3期35-39,共5页
以英国北爱尔兰Hayes的一块牧草地为研究区,将所有样点分为独立的训练和检验数据集,并在训练样点集的基础上设计了其他4种样点布局方案,以研究神经网络集成技术应用于田间土壤性质空间变异性的可能性。与广泛应用的克里格法的试验结果相... 以英国北爱尔兰Hayes的一块牧草地为研究区,将所有样点分为独立的训练和检验数据集,并在训练样点集的基础上设计了其他4种样点布局方案,以研究神经网络集成技术应用于田间土壤性质空间变异性的可能性。与广泛应用的克里格法的试验结果相比,集成BP神经网络的插值结果精度与之基本相当,尤其是在样点分布较稀疏和样点数较少的情况下,集成BP网络表现出明显的优势;由于神经网络集成方法对样本数据的分布没有任何要求,因此具有较广泛的应用前景和潜力,并在不符合克里格法对样本数据分布要求的情况下是一种可行的替代方法。 展开更多
关键词 神经网络集成 BP网络 土壤性质 空间变异 克里格插值法
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应用广义回归神经网络进行土壤空间变异研究 被引量:55
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作者 沈掌泉 周斌 +1 位作者 孔繁胜 John S.Bailey 《土壤学报》 CAS CSCD 北大核心 2004年第3期471-475,共5页
关键词 广义回归神经网络 土壤性质 空间变异 空间插值技术 地统计学
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超级杂交稻干物质生产特点与产量稳定性研究 被引量:130
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作者 敖和军 王淑红 +6 位作者 邹应斌 彭少兵 唐启源 方远祥 肖安民 陈玉梅 熊昌明 《中国农业科学》 CAS CSCD 北大核心 2008年第7期1927-1936,共10页
【目的】探明超级杂交稻在不同种植地点和不同施肥量条件下的产量表现及干物质生产特点。【方法】于2004~2005年在湖南省桂东、长沙、衡阳、南县和永州5个地点进行大田试验,按照N﹕P2O5﹕K2O为1﹕0.5﹕1的比例,设置3种施肥量处理(135、... 【目的】探明超级杂交稻在不同种植地点和不同施肥量条件下的产量表现及干物质生产特点。【方法】于2004~2005年在湖南省桂东、长沙、衡阳、南县和永州5个地点进行大田试验,按照N﹕P2O5﹕K2O为1﹕0.5﹕1的比例,设置3种施肥量处理(135、180、225kgN·ha-1),田间采用随机区组排列,4次重复,以超级杂交稻组合准两优527和两优293为试验材料。【结果】超级杂交稻收获产量以桂东点产量最高,地点间差异显著,其中准两优527平均为7492.3~12209.2kg·ha-1,两优293为6984.0~11679.5kg·ha-1。产量构成因子和干物质生产量的地点间变化与收获产量一致,但在同一地点的不同施肥量处理间收获产量和干物质生产量差异均不显著。收获产量与单位面积穗数、结实率和千粒重表现为正相关,而与每穗粒数表现为负相关。【结论】超级杂交稻存在适宜的种植区域,且在施肥量为135~225kgN·ha-1的范围内,施肥量不是超高产栽培的限制因子。超级杂交稻的库容量大,提高结实率和粒重是获得超高产的可能途径。 展开更多
关键词 超级杂交稻 产量稳定性 干物质生产 肥料用量
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不同林型土壤微生物有机碳降解基因的多样性 被引量:13
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作者 张于光 张小全 +2 位作者 刘学端 肖烨 Wu Liyou 《生态学报》 CAS CSCD 北大核心 2007年第4期1412-1419,共8页
应用寡聚核苷酸基因芯片,分析了米亚罗林区冷杉原始林(M-Y)和20世纪60年代云杉人工林(M-60)土壤微生物的功能基因多样性。该功能基因芯片含有与有机碳降解、碳固定、氮、磷、硫循环和金属抗性相关的1961个基因探针。在M-Y和M-60样地中... 应用寡聚核苷酸基因芯片,分析了米亚罗林区冷杉原始林(M-Y)和20世纪60年代云杉人工林(M-60)土壤微生物的功能基因多样性。该功能基因芯片含有与有机碳降解、碳固定、氮、磷、硫循环和金属抗性相关的1961个基因探针。在M-Y和M-60样地中分别检测到39和62个具有较强杂交信号(SNR≥2)的功能基因,其基因多样性水平指数分别为3.59和4.04,杂交信号强度总值分别为480280和630560。M-Y和M-60样地中分别检测到32个和37个有机碳降解基因,占总基因的82%和60%,这些基因分属于22个不同的基因类群,分别参与木质素、木聚糖、几丁质等有机碳的降解过程。有机碳降解基因在两个样地中存在较大的多样性和丰度差异。这些结果说明了大多数的土壤微生物直接参与了土壤有机碳的降解,同时,林型不同显著影响了土壤微生物群落结构和有机碳降解微生物的多样性。 展开更多
关键词 土壤有机碳 功能基因芯片 林型 基因多样性
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不同CO_2浓度下苦槠(Castanopsis sclerophylla)叶片光合光响应模型模拟比较 被引量:8
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作者 唐星林 曹永慧 +2 位作者 周本智 周燕 顾连宏 《生态学杂志》 CAS CSCD 北大核心 2017年第7期2060-2067,共8页
以亚热带森林建群种苦槠为试验材料,采用5种光响应模型对4个CO_2浓度下苦槠叶片的光响应曲线进行模拟,比较不同CO_2浓度下适宜的光响应模型,探讨苦槠对CO_2浓度变化的响应规律。结果表明:5种模型对苦槠叶片光响应曲线的拟合效果优劣次... 以亚热带森林建群种苦槠为试验材料,采用5种光响应模型对4个CO_2浓度下苦槠叶片的光响应曲线进行模拟,比较不同CO_2浓度下适宜的光响应模型,探讨苦槠对CO_2浓度变化的响应规律。结果表明:5种模型对苦槠叶片光响应曲线的拟合效果优劣次序为直角双曲线修正模型>指数改进模型>指数模型>非直角双曲线模型>直角双曲线模型;直角双曲线修正模型对光饱和点(LSP)和最大净光合速率(Pmax)的拟合效果最好,非直角双曲线模型对暗呼吸速率(Rd)的拟合效果最好;5种光响应模型对不同CO_2浓度有不同的适应性,直角双曲线模型、指数模型和直角双曲线修正模型适合低CO_2浓度,非直角双曲线模型适合高CO_2浓度;随CO_2浓度的增加,光补偿点(LCP)和Rd逐渐减小而Pmax逐渐增大;CO_2浓度的增大可以提高苦槠的光合能力及其对弱光的利用能力,并抑制呼吸作用。 展开更多
关键词 光响应模型 净光合速率 苦槠 CO2浓度 光响应参数
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