检索结果-南通市图书馆

Edge Effect Correction in the S-A Method for Geochemical Anomaly Separation

在线全文

学校读者我要写书评

暂无评论

Journal of china University of Geosciences 2004年第4期15卷 379-387页

作者： Ge Yong Department of Earth and Atmospheric Science, York University, Toronto, ON, M3. 1P3. Canada State key laboratory of resources and {3.al Information System, Institute of Geographic Sciences & Natural resources Research, Chinese Academy of Sciences, beijing 100101, china Cheng Qiuming Department of Earth and Atmospheric Science, York University, Toronto, ON, M3. 1P3. Canada Earth Systems and Mineral resource Engineering lab, china University of Geosciences, Wuhan 43.074, china Zhang Shenyuan Department of Earth and Atmospheric Science, York University, Toronto, ON, M3. 1P3. Canada Department of resource and Earth Science, china University of Mining & Technology, beijing 100083. china Department of Earth and Atmospheric Science York University Toronto ON M3J 1P3 Canada State key laboratory of resources and {3.al Information System Institute of Geographic Sciences & Natural Resources Research Chinese Academy of SciencesBeijing 100101China Department of Earth and Atmospheric Science York University Toronto ON M3J 1P3 Canada Earth Systems and Mineral resource Engineering lab China University of Geosciences Wuhan 430074 China Department of Earth and Atmospheric Science York University Toronto ON M3J 1P3 Canada Department of resource and Earth Science China University of Mining & Technology Beijing 100083 China

Anomaly separation using geochemical data often involves operations in the frequency domain, such as filtering and reducing noise/signal ratios. Unfortunately, the abrupt edge truncation of an image along edges and holes (with missing data) often causes frequency distribution distortion in the frequency domain. For example, bright strips are commonly seen in frequency distribution when using a Fourier transform. Such edge effect distortion may affect information extraction results; sometimes severely, depending on the edge abruptness of the image. Traditionally, edge effects are reduced by smoothing the image boundary prior to applying a Fourier transform. Zero-padding is one of the most commonly used smoothing methods. This simple method can reduce the edge effect to some degree but still distorts the image in some cases. Moreover, due to the complexity of geoscience images, which can include irregular shapes and holes with missing data, zero-padding does not always give satisfactory results. This paper proposes the use of decay functions to handle edge effects when extracting information from geoscience images. As an application, this method has been used in a newly developed multifractal method (S-A) for separating geochemical anomalies from background patterns. A geochemical dataset chosen from a mineral district in Nova Scotia, Canada was used to validate the method.

关键词： edge effect correction fractal modeling spatial information extraction zero-padding decay functions.

在线全文

学校读者我要写书评

暂无评论

浅层地下水水质系统碘浓度场数值仿真

系统仿真学报 2002年第5期14卷 653-655页

作者：宫辉力赵文吉诸云强首都师范大学资源环境与旅游学院

基于地下水系统概念模型分析,采用准三维数值仿真技术,建立了由地下水水流模型、溶质运移模型和地下水运动方程组成的地下水水质模型。先解地下水水流模型,得到地下水渗流场水位函数H(x, y, t);再解地下水运动方程得到各单元的地下水实... 详细信息

基于地下水系统概念模型分析,采用准三维数值仿真技术,建立了由地下水水流模型、溶质运移模型和地下水运动方程组成的地下水水质模型。先解地下水水流模型,得到地下水渗流场水位函数H(x, y, t);再解地下水运动方程得到各单元的地下水实际流速;最后解溶质运移模型,求出计算区内任一点的溶质浓度。数值计算结果表明,水质模型仿真性能良好。

关键词：浅层地下水水质系统碘浓度场数值仿真

Evidence from carbon isotope measurements for biological origins of individual long-chain n-alkanes in sediments from the Nansha Sea,china

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2002年第7期47卷 578-581页

作者： DUAN Yi & WANG ZhipingState key laboratory of Gas Geochemistry, Lanzhou Institute of Geology, Chinese Academy of Sciences, Lanzhou 73.000, china Institute of {3.al Science, beijing Normal University, beijing 100875, china State key laboratory of Gas Geochemistry Lanzhou Institute of Geology Chinese Academy of Sciences Lanzhou China Institute of environmental Science Beijing Normal University Beijing China

Carbon isotopes are measured for individual long-chain n-alkanes in sediments from the Nansha Sea. The features of carbon isotopic compositions of individual n-alkanes and their origins are studied. The results show that the long-chain n-alkanes have a light carbon isotopic composition and a genetic feature of mixing sources, and low-latitude higher plants and microbes are considered to be their main end member sources. Based on the abundances and carbon isotopic compositions of individual n-alkanes, the fractional contributions of the two end member sources to individual n-alkanes are quantitatively calculated by using a mixing model. The obtained data indicate that the fractional contributions of the two biological sources are different in the three samples. A trend is that the contribution of microbes increases with the depth. These results provide the theory basis and quantitatively studied method for carbon isotopic applied research of individual n-alkanes.

关键词： modern marine sediment individual n-alkane carbon isotopic composition biological source.

Effects of humic acids and microorganisms on decabromodiphenyl ether, 4,4′-dibromodiphenyl ether and anthracene transportation in soil

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2010年第4期53卷 950-958页

作者： YU Sheng, ZOU Peng, ZHU Wei, YANG LiuYan, XIAO Lin, JIANG LiJuan, WANG XiaoLin, WU Jun & YUAN Ye State key laboratory of Pollution Control and resource Reuse School of the {3., Nanjing University, Nanjing 210093. china State key laboratory of Pollution Control and resource Reuse Nanjing University Nanjing China School of the environment Nanjing University Nanjing China

In this study, effects of humic acids (HA) and microorganisms on the migration of hydrophobic organic contaminants (HOCs), decabromodiphenyl ether (BDE-209), 4,4′-dibromodiphenyl ether (BDE-15) and anthracene, in soils were examined. More soil particles were dispersed into the colloidal phase (0.22-1 μm) in the presence of HA and/or microorganisms as a result of increased erosion and friction. The study suggested that PBDEs (BDE-209 and BDE-15) and anthracene in soils would be transported to other places by soil colloids with surface and underground water flow given the high concentrations of HA and microorganisms in the natural environment.

关键词： humic acids microorganisms transportation hydrophobic organic contaminants soil colloid

Crop Yield and Soil Responses to Long-Term Fertilization on a Red Soil in Southern china

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2009年第2期19卷 199-207页

作者： ZHANG Hui-Min WANG Bo-Ren XU Ming-Gang FAN Ting-Lu key laboratory of Plant Nutrition and Nutrient Cycling Ministry of Agriculture of China and Institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural Sciences Beijing 100081 China Department of resource and environment Northwest Sci-Tech University of Agriculture and Forestry Yangling 712100 China Department of Agronomy Henan University of Science and Technology Luoyang 471003 China

A 15-year fertilization experiment with different applications of inorganic N,P and K fertilizers and farmyard manure (M)was conducted to study the yield and soil responses to long-term fertilization at Qiyang,Hunan Province,china. Average grain yields of wheat and corn(1 672 and 5 111 kg ha-1,respectively)for the treatment NPKM were significantly higher than those(405 and 3.0 kg ha-1)of the unfertilized control and single inorganic fertilizer *** with the corresponding initial values of the experiment,all treatments showed a yield decline of 9 to 111 kg ha-1 year-1 in wheat and 3. to 260 kg ha-1 year-1 in corn,respectively,and a significant pH decline of 0.07 to 0.12 pH year?1,except for the treatments PK and *** long-term fertilization,the soil organic C,soil available P,exchangeable Ca2+ and Mg2+and available Cu2+and Zn2+contents were higher in the treatment NPKM than in the treatments applied with inorganic fertilizer *** to the treatment NPK,the treatment NPKM,where manure partially replaced inorganic N,had a positive impact on arresting the decline of soil *** improved grain yields of wheat and corn, suggesting that application of NPK fertilizer in combination with farmyard manure is important to maintain soil fertility and buffering capacity in red soil.

关键词： corn long-term fertilization red soil wheat yield

Effects of Amino Acids Replacing Nitrate on Growth,Nitrate Accumulation,and Macroelement Concentrations in Pak-choi (Brassica chinensis L.)

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2007年第5期17卷 595-600页

作者： WANG Hua-Jing WU Liang-Huan WANG Min-Yan ZHU Yuan-Hong TAO Qin-Nan ZHANG Fu-Suo Ministry of Education key laboratory of environmental Remediation and Ecosystem Health College of Environmental and Resource Sciences Zhejiang University Hangzhou 310029 （China） College of Geography and resource Sciences Sichuan Normal University Chengdu 610066 （China） Department of Crop and Soil Sciences the Pennsylvania State University （USA） College of resources and environment China Agricultural University Beijing 100094 （China）

A hydroponic experiment was carried out to determine the influence of replacing 20% of nitrate-N in nutrient solutions with 20 individual amino acids on growth, nitrate accumulation, and concentrations of nitrogen （N）, phosphorus （P）, and potassium （K） in pak-choi （Brassica chinensis L.） shoots. When 20% of nitrate-N was replaced with arginine （Arg） compared to the full nitrate treatment, pak-choi shoot fresh and dry weights increased significantly （P ≤ 0.05）, but when 20% of nitrate-N was replaced with alanine （Ala）, valine （Val）, leucine （Leu）, isoleucine （Ile）, proline （Pro）, phenylalanine （Phe）, methionine （Met）, aspartic acid （Asp）, glutamic acid （Glu）, lysine （Lys）, glycine （Gly）, serine （Ser）, threonine （Thr）, cysteine （Cys）, and tyrosine （Tyr）, shoot fresh and dry weights decreased significantly （P ≤ 0.05）. After replacing 20% of nitrate-N with asparagine （Asn） and glutamine （Gin）, shoot fresh and dry weights were unaffected. Compared to the full nitrate treatment, amino acid replacement treatments, except for Cys, Gly, histidine （His）, and Arg, significantly reduced （P ≤0.05） nitrate concentrations in plant shoots. Except for Cys, Leu, Pro, and Met, total N concentrations in plant tissues of the other amino acid treatments significantly increased （P ≤ 0.05）. Amino acids also affected total P and K concentrations, but the effects differed depending on individual amino acids. To improve pak-choi shoot quality, Gln and Asn, due to their insignificant effects on pak-choi growth, their significant reduction in nitrate concentrations, and their increase in macroelement content in plants, may be used to partially replace nitrate-N.

关键词： amino acids growth N P and K nitrate accumulation pak-choi

Resistance to chemical attack of bittern-resisting cement in high-bittern environment

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2005年第5期 87-93页

作者： Yunbing Hou, Bingwen Wang, Yu Chen, Botao Zhang, and Lin Yu School of resource & Safety Engineering, china University of Mining & Technology (beijing), beijing 100083. china

A new kind of bittern-resisting cement (BRC) was introduced. This material is based on the ternary cementitious system of clinker containing C4A3.S phase, high-activity ground granulated blast-furnace slag (GGBFS) and fly ash (FA). The hydration proc- ess and the hydrated products of BRC were studied by means of XRD, TG-DTA and SEM, and the resistance to chemical attack of BRC in high-bittern environment was also examined. The corrosion experiment in seven kinds of brines proved that BRC exhibits an excellent resistance to chemical attack of bittern. The corrosion resistance factors were calculated and all of them were greater than 0.96. It showed that BRC totally controls the cement-based material corrosion in brines from four aspects: (1) making full use of the dominant complementation effect of mineral materials; (2) diminishing the hydrated products easy to be attacked; (3. improving the microstructure of hardened cement mortar; (4) degrading the chemical attack of bittern.

关键词： bittern-resisting cement ternary cementitious system high-activity mineral materials resistance to chemical attack bit- tern corrosion resistance factor corrosion mechanism

Investigation on Co-Combustion Kinetics of Anthracite and Waste Plastics by Thermogravimetric Analysis

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2012年第10期19卷 30-35页

作者： LIU Zheng-jian, REN Shan, ZHANG Jian-liang, LIU Wei-jian, XING Xiang-dong, SU Bu-xin (State key laboratory of Advanced Metallurgy, University of Science and Technology beijing, beijing 100083. china) State key laboratory of Advanced Metallurgy University of Science and Technology Beijing Beijing China

In order to effectively recycle resource for the benefit of the global environment, the utilization of waste plastics as auxiliary injectant for blast furnaces is becoming increasingly important. Combustion kinetics of plastics-coal blends with 0, 10%, 20% and 40% waste plastics (WP) are investigated separately by thermogravimetric analysis (TGA) from ambient temperature to 900 ℃ in air atmosphere. These blends are combusted at the heating rates of 5, 10 and 20 ℃/min. The results indicate that, with the increase of waste plastics content, the combustion processes of blends could be divided into one stage, two stages and three stages. The waste plastics content and heating rates have important effects on the main combustion processes of blends. With the increase of waste plastics content, the ignition temperature and the final combustion temperature of blends tend to decrease, while the combustion reaction becomes fiercer. With the increase of the heating rate, the ignition temperature, the mass loss rate of the peaks and the final combustion temperature of blends combustion tend to increase. The Flynn-Wall-Ozawa (FWO) iso-conversional method is used for the kinetic analysis of the main combustion process. The results indicate that, when the waste plastics content varied from 0 to 40%, the values of activation energy increase from 126.05 to 184.12 kJ /mol.

关键词： waste plastics anthracite co-combustion kinetics TGA iso-conversional method

Change in Sediment Load of the Yangtze River after Wenchuan Earthquake

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2010年第1期7卷 100-104页

作者： CHENG Genwei HE Xiubin CHEN Guirong TAO Heping key laboratory of Mountain environment Evolvement and Regulation. Institute of Mountain Hazards & environment CAS Chengdu 610041 China Siehuan Hydrology &Water resource Survey Bureau Chengdu 610041 China

On May 12, 2008, an earthquake of 8.0 magnitude on the Richter scale and its numerous aftershocks devastatingly hit Wenchuan County and its nearby region along the Longman Mountains in Sichuan Province, china. The heavy ruined area was up to 3.,000km2 and 13. of its land surface was denuded by the extremely terrible quakes. The mountain collapses, landslides and debris flows induced by the earthquake not only scared the landscape at the immense scale, but also poured L66-billion-m3.sediment combined with offscourings and rubble into the Yangtze River and its breaches. This amount of sediments is 3.times more than the normal amount discharged into the Yangtze River, and will significantly increase sediment transportation of rivers and decrease storage capacities of reservoirs downstream. The dramatic increase in sediment load will imperil the engineering safety and impact the operation of the giant Three-Gorge Hydro-power Station if no proper prevention measures are taken.

关键词： Wenchuan earthquake sediment load the Yangtze River