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建筑物体量对烟源扩散和环境质量的影响分析
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作者 程昊淼 戴俭 陈东升 《山西建筑》 2009年第20期21-23,共3页
基于建筑物对污染物扩散的影响,利用Matlab系统开发的建筑物体量与空气质量识别系统,针对城市采暖锅炉烟囱污染物排放源特征,分析了建筑物体量对下风向区域污染物的扩散影响及浓度分布,结合建筑物对风的阻挡和扰流影响,探索了场地规划... 基于建筑物对污染物扩散的影响,利用Matlab系统开发的建筑物体量与空气质量识别系统,针对城市采暖锅炉烟囱污染物排放源特征,分析了建筑物体量对下风向区域污染物的扩散影响及浓度分布,结合建筑物对风的阻挡和扰流影响,探索了场地规划和建筑设计中已有污染源的影响因素。 展开更多
关键词 建筑物体量 大气污染源 排放高度 扩散 空气质
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物体量表达的认知语义基础 被引量:7
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作者 李先银 《语言教学与研究》 CSSCI 北大核心 2003年第6期17-23,共7页
本文从认知域的划分和名词的指称两个方面探讨了物体量表达的实质及其功能表现。我们认为物体量成分和其他定语成分一样,是确立认知域成员的标准,使名词定指化。
关键词 物体量 认知域 名词 指称 认知语义基础 功能表现.
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Syntheses,crystal structures,and quantum chemistry calculation of two Ni(Ⅱ)coordination polymers
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作者 LI Xiumei HUANG Yanju +1 位作者 LIU Bo PAN Yaru 《无机化学学报》 SCIE CAS CSCD 北大核心 2024年第10期2031-2039,共9页
Two new coordination polymers,[Ni(Hpdc)(bib)(H_(2)O)]_(n)(1)and{[Ni(bib)_(3)](ClO_(4))_(2)}_(n)(2),were prepared by mixing Ni^(2+),3,5⁃pyrazoledicarboxylic acid(H3pdc)/p⁃nitrobenzoic acid and 1,4⁃bis(imidazol⁃1⁃ylmeth... Two new coordination polymers,[Ni(Hpdc)(bib)(H_(2)O)]_(n)(1)and{[Ni(bib)_(3)](ClO_(4))_(2)}_(n)(2),were prepared by mixing Ni^(2+),3,5⁃pyrazoledicarboxylic acid(H3pdc)/p⁃nitrobenzoic acid and 1,4⁃bis(imidazol⁃1⁃ylmethyl)butane(bib)by a hydrothermal method,respectively.X⁃ray crystallography reveals a 2D network constructed by six⁃coordinated Ni(Ⅱ)centers,bib,and Hpdc2-ligands in complex 1,while a 2D network is built by Ni(Ⅱ)and bib ligands in 2.Furthermore,the quantum⁃chemical calculations have been performed on‘molecular fragments’extracted from the crystal structure of 1 using the PBE0/LANL2DZ method in Gaussian 16 and the VASP program.CCDC:2343794,1;2343798,2. 展开更多
关键词 coordination polymer nickel(Ⅱ)complex crystal structure quantum⁃chemical calculation
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Self-adapting extraction of matrix mineral bulk modulus and verification of fluid substitution 被引量:5
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作者 林凯 熊晓军 +4 位作者 杨晓 贺振华 曹俊兴 张玺华 王萍 《Applied Geophysics》 SCIE CSCD 2011年第2期110-116,176,共8页
Gassmann's equations are commonly used for predicting seismic wave velocity in rock physics research.However the input matrix mineral bulk modulus parameters are not accurate,which greatly influences the prediction r... Gassmann's equations are commonly used for predicting seismic wave velocity in rock physics research.However the input matrix mineral bulk modulus parameters are not accurate,which greatly influences the prediction reliability.In this paper,combining the Russell fluid factor with the Gassman-Biot-Geertsma equation and introducing the dry-rock Poisson's ratio,we propose an effective matrix mineral bulk modulus extraction method.This method can adaptively invert the equivalent matrix mineral bulk modulus to apply the Gassmann equation to fluid substitution of complex carbonate reservoirs and increase the fluid prediction reliability.The verification of the actual material fluid substitution also shows that this method is reliable,efficient,and adaptable. 展开更多
关键词 Self-adapting matrix mineral bulk modulus fluid substitution dry rock Poisson's ratio
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Genetic Analysis of a Biomass Mutant in Oryza sativa 被引量:12
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作者 廖子荣 黄东益 +2 位作者 牛杰 李俏 吴安迪 《Agricultural Science & Technology》 CAS 2008年第2期63-66,共4页
[ Objective ] The study aimed to reveal the genetic model of a biomass mutant in Oryza sativa. [ Method ] In the process of screening and identification of Bar-transgenic rice, a biomass mutant was found in 10 lines o... [ Objective ] The study aimed to reveal the genetic model of a biomass mutant in Oryza sativa. [ Method ] In the process of screening and identification of Bar-transgenic rice, a biomass mutant was found in 10 lines of T1 progenies. The mutant was investigated for genetic analysis and agronomic traits by herbicide spraying and PCR amplification. [ Result] The segregation ratio is consistent with mendelian law(3:1). The mutant assumed not only higher plant height, wider straw and earlier florescence, but also more tillers, bigger spikes and resultantly higher biomass. PCR detections indicated that no co-segregation was observed between mutant traits and target gene(Bar) in the T-DNA inserted, proving that the mutant is not caused by the insertion of T-DNA containing target gene (Bar). [ Conclusion] Our study may avail to understand the cloning of mutant gene and the mechanism of the mutant gene on biomass. 展开更多
关键词 Oryza sativa BIOMASS MUTANT Genetic analysis
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A preliminary study on in-stream large woody debris in broadleaved and Korean pine forest in Changbai Mountain, Northeast China 被引量:2
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作者 邓红兵 王青春 王庆礼 《Journal of Forestry Research》 SCIE CAS CSCD 2002年第3期196-200,251,共5页
This study was conducted in Erdaobaihe River passing through the broadleaved and Korean pine forest located on the north slope of Changbai Mountain. In-stream large woody debris (LWD) in two segments of the river chan... This study was conducted in Erdaobaihe River passing through the broadleaved and Korean pine forest located on the north slope of Changbai Mountain. In-stream large woody debris (LWD) in two segments of the river channel was investigated with base diameter, top diameter, length, and decay class. To study relationship between in-stream LWD and adjacent riparian forest, species of each log of LWD in segment 1 was identified, and the riparian forest was examined by setting a 32m?4 m quadrat consisting of twelve 8m?m small quadrats. The results showed that, in segment 1, in-stream LWD loading was 1.733 m3/100m or 10.83 m3hm-2, and in segment 2, it was 1.709m3/100m or 21.36 m3hm-2. In-stream LWD in decay class III and IV were accounted for a high proportion, which was different from that in the broadleaved and Korean pine forest, and the possible reason might be different decomposing velocities due to different decomposing conditions. Logs of LWD in stream and living trees in riparian forest declined as diameter increased, and it was in a reverse J-shaped distribution except logs of LWD in segment 1 in the first diameter class. Volumes of LWD in stream and living trees in riparian forest increased as diameter increased, and it was in a typical J-shaped distribution. Loading and species component of in-stream LWD were correlative to status of riparian forest to a certain extent, and there also existed difference. Comparing the correlation and difference was helpful to study on dynamic of the riparian forest. 展开更多
关键词 In-stream large woody debris Broadleaved and Korean pine forest Changbai Mountain LOADING Riparian zone
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Algorithm and System of Scanning Color 3D Objects 被引量:1
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作者 许智钦 孙长库 郑义忠 《Transactions of Tianjin University》 EI CAS 2002年第2期134-138,共5页
This paper presents a complete system for scanning the geometry and texture of a large 3D object, then the automatic registration is performed to obtain a whole realistic 3D model. This system is composed of one line ... This paper presents a complete system for scanning the geometry and texture of a large 3D object, then the automatic registration is performed to obtain a whole realistic 3D model. This system is composed of one line strip laser and one color CCD camera. The scanned object is pictured twice by a color CCD camera. First, the texture of the scanned object is taken by a color CCD camera. Then the 3D information of the scanned object is obtained from laser plane equations. This paper presents a practical way to implement the three dimensional measuring method and the automatic registration of a large 3D object and a pretty good result is obtained after experiment verification. 展开更多
关键词 D measurement color 3D object laser scanning surface construction
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数和数学的现实原型
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作者 敬石心 肖玉山 《长春大学学报》 2006年第12期145-147,共3页
数和数学源于客观现实,数学的形成、发展,初等数学和现代数学的创立与社会历史发展、科学技术的进步相适应。从数的使用到数学的创立,是个充满矛盾的认识过程。抽象性、相对独立性是数学的基本特征。数学理论、原理及诸多的数学概念、... 数和数学源于客观现实,数学的形成、发展,初等数学和现代数学的创立与社会历史发展、科学技术的进步相适应。从数的使用到数学的创立,是个充满矛盾的认识过程。抽象性、相对独立性是数学的基本特征。数学理论、原理及诸多的数学概念、公式是外部世界的物体的量和量的关系的反映,是人类思维活动发展的必然结果。现实世界是数学的无限原型。 展开更多
关键词 现代数学 抽象性 相对独立性 物体 现实原型
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PREPARATION AND CHARACTERIZATION OF WATER-SOLUBLE NEAR-INFRARED EMITTING PbS QUANTUM DOTS
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作者 曹洁 李杉 +1 位作者 邓大伟 顾月清 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2010年第1期81-87,共7页
A new facile method for preparing water-soluble near-infrared (NIR)-emitting PbS quantum dots (QDs) is proposed by using N-acetyl-L-cysteine (NAC, a derivate of L-cysteine) as its stabilizer. The influence of th... A new facile method for preparing water-soluble near-infrared (NIR)-emitting PbS quantum dots (QDs) is proposed by using N-acetyl-L-cysteine (NAC, a derivate of L-cysteine) as its stabilizer. The influence of the precursor Pb/S molar ratio, the Pb/NAC molar ratio, and the pH of original solution on optical properties is explored. Results show that aqueous PbS QDs with strong NIR fluorescence can be prepared and their photoluminescence emission peaks can be tuned from 895 nm to 970 nm. Studies indicate that such aqueous QDs have a potential application in biomedical imaging, especially in noninvasive in vivo fluorescence imaging. In addition, the resulting PbS QDs are further characterized by a transmission electron microscopy and X-ray diffraction analysis. 展开更多
关键词 semiconductor quantum dots (QDs) biomedical imaging N-acetyl-L-cystelne(NAC) NEAR-INFRARED
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Effects of Reduced Nitrogen Fertilization and Biochar Application on CO_2 and N_2O Emissions from a Summer Maize-Winter Wheat Rotation Field in North China 被引量:1
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作者 韩雪 范靖尉 +4 位作者 白晋华 任寰宇 李迎春 刁田田 郭李萍 《Agricultural Science & Technology》 CAS 2016年第12期2800-2808,共9页
This experiment was conducted in Xinxiang, Henan from June 2013 to June 2014. Total four treatments were designed including farmers ’ common practice (F, 250 kg/hm^2), 80% F (LF, 200 kg/hm^2), 80% F+biochar (LF... This experiment was conducted in Xinxiang, Henan from June 2013 to June 2014. Total four treatments were designed including farmers ’ common practice (F, 250 kg/hm^2), 80% F (LF, 200 kg/hm^2), 80% F+biochar (LFC) and no fertilizer (CK) to measure the dynamic emissions of CO2 and N2O from a summer maize-winter wheat field by static chamber-gas chromatography method. The results showed that the soil CO2 emission was 21.8-1 022.7 mg/(m^2·h), and was mainly influenced by soil temperature and moisture content. During the growth of summer maize, the soil CO2 emission was more significantly affected by soil moisture con-tent; and in winter wheat growing season, it was more significantly affected by soil temperature in the top 5 cm. The LF and LFC treatments significantly reduced the soil cumulative CO2 emission, especial y during the growth of winter wheat. Fertiliza-tion and irrigation were the main factors influencing the soil N2O emission. The soil N2O emission during the fertilization period accounted for 73.9%-74.5% and 40.5%-43.6% of the soil cumulative N2O emission during the summer maize-and winter wheat-growing season, respectively. The peak of emission fluxes was determined by fertilization amount, while the occurrence time of emission peak and emission re-duction effect were influenced by irrigation. The LF treatment reduced the soil cu-mulative N2O emission by 15.7%-16.8% and 18.1%-18.5% during the growth period of summer maize and winter wheat, respectively. Reduced nitrogen fertilization is an effective way for reducing N2O emission in intensive high-yielding farmland. Under a suitable nitrogen level (200 kg/hm^2), the application of biochar showed no significant effect on the soil N2O emission in a short term. The N2O emission factors of the L and LF treatments were 0.60% and 0.56%, respectively. ln the intensive high-yield-ing farmland of North China, reducing the nitrogen application amount is an appro-priate measure to mitigate greenhouse gas emissions without crop yield loss. 展开更多
关键词 Reduced nitrogen fertilization BIOCHAR Greenhouse gas emissions N2O emission Winter wheat-summer maize
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排序活动中的美感教育
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作者 黄润芳 《山东教育》 1999年第9期20-21,共2页
排序活动中的美感教育成都黄润芳排序是将两个以上的物体按某种特征上的差异或规则排列成序。排列成序的事物所呈现的各种形式可以给人一种顺序美、渐变美、动态美和变化美的享受。对幼儿进行排序教育不仅有助于他们学习计数,认识数的... 排序活动中的美感教育成都黄润芳排序是将两个以上的物体按某种特征上的差异或规则排列成序。排列成序的事物所呈现的各种形式可以给人一种顺序美、渐变美、动态美和变化美的享受。对幼儿进行排序教育不仅有助于他们学习计数,认识数的顺序,建立起数序概念,理解抽象的数... 展开更多
关键词 幼儿 形式美 审美经验 体育活动 美感教育 序列变化 物体量 音乐活动 审美兴趣 动手操作活动
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Part-level 3-D object classification with improved interpretation tree
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作者 邢薇薇 刘渭滨 袁保宗 《Journal of Southeast University(English Edition)》 EI CAS 2007年第2期221-225,共5页
For classifying unknown 3-D objects into a set of predetermined object classes, a part-level object classification method based on the improved interpretation tree is presented. The part-level representation is implem... For classifying unknown 3-D objects into a set of predetermined object classes, a part-level object classification method based on the improved interpretation tree is presented. The part-level representation is implemented, which enables a more compact shape description of 3-D objects. The proposed classification method consists of two key processing stages: the improved constrained search on an interpretation tree and the following shape similarity measure computation. By the classification method, both whole match and partial match with shape similarity ranks are achieved; especially, focus match can be accomplished, where different key parts may be labeled and all the matched models containing corresponding key parts may be obtained. A series of experiments show the effectiveness of the presented 3-D object classification method. 展开更多
关键词 3-D object classification shape match similarity measure interpretation tree
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Comparison of Fe^(2+) oxidation by Acidithiobacillus ferrooxidans in rotating-drum and stirred-tank reactors 被引量:2
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作者 金建 石绍渊 +2 位作者 刘国梁 张庆华 丛威 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第3期804-811,共8页
Fe2+ oxidation by Acidithiobacillus ferrooxidans(At.ferrooxidans) under different solid contents by adding inert Al2O3 powder was examined in rotating-drum and stirred-tank reactors.The results show that the bioact... Fe2+ oxidation by Acidithiobacillus ferrooxidans(At.ferrooxidans) under different solid contents by adding inert Al2O3 powder was examined in rotating-drum and stirred-tank reactors.The results show that the bioactivity of At.ferrooxidans in the stirred-tank is higher than that in the rotating-drum in the absence of Al2O3 powder,but the biooxidation rate of Fe2+ decreases markedly from 0.23 g/(L·h) to 0.025 g/(L·h) with increasing the content of Al2O3 powder from 0 to 50%(mass fraction) in the stirred-tank probably due to the deactivation of At.ferrooxidans resulting from the collision and friction of solid particles.The increase in Al2O3 content has a little adverse effect on the bioactivity of At.ferrooxidans in the rotating-drum due to different mixing mechanisms of the two reactors.The biooxidation rate of Fe2+ in the rotating-drum is higher than that in the stirred-tank at the same content of Al2O3 powder,especially at high solid content.The higher bioactivity of At.ferrooxidans can be maintained for allowing high solid content in the rotating-drum reactor,but its application potential still needs to be verified further by the sulfide bioleaching for the property differences of Al2O3 powder and sulfide minerals. 展开更多
关键词 Fe2+ Acidithiobacillus ferrooxidans OXIDATION bioactivity solid content rotating-drum reactor stirred-tank reactor
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Mutagenesis and selection of high efficiency hydrogen-producing mutants by ultraviolet radiation 被引量:5
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作者 任南琪 郑国香 +2 位作者 李永峰 林海龙 李建政 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2006年第6期635-639,共5页
Hydrogen is an ideal, clean and sustainable energy source for the future because of its high conversion and nonpolluting nature. Biohydrogen production by dark-fermentation appears to have a great potential to be deve... Hydrogen is an ideal, clean and sustainable energy source for the future because of its high conversion and nonpolluting nature. Biohydrogen production by dark-fermentation appears to have a great potential to be developed for practical application. However, one limiting factor affecting the development of hydrogen-production industrialization is that the hydrogen-producing capacity of bacteria is lower, so how to increase bacteria' s hydrogen-producing ability will be an urgent issue. In this experiment, 2 mutants, namely UV3 and UV7, were obtained by ultra-violet radiation. They grew and produced hydrogen efficiently on iron-containing medium. The hydrogen evolution of UV3 and UV7 were 2 356. 68 ml/L and 2 219. 62 ml/L at a glucose concentration of 10 g/L, respectively. With wild parent strain Ethanoligenens sp. ZGX4, the hydrogen evolution was 1 806. 02 ml/L under the same conditions. Mutants' hydrogen-producing capacities were about 29. 71% and 22.22% higher than that of wild parent strain ZGX4. The maximum H2 production rate by mutants UV3 and UV7 were estimated to be 32.57 mmol H2/g cell h and 31.19 mmol H2/g cell h, respectively, which were 38. 18% and 34. 78% higher than the control (23.57 mmol H:/g cell h). The abundant products of UV3 and UV7 were ethanol and acetic, which accounted for 95% - 98% of total soluble microbial products. In each case, mutant strains UV3 and UV7 evolved hydrogen at a higher rate than the wild type, showing a possible potential for commercial hydrogen production. Another mutant named UV20' was also gained whose main end metabolites were butyric acid and acetic acid. This would provide researched material for a discussion of metabolic pathways of hydrogen-producing bacteria. 展开更多
关键词 BIOHYDROGEN UV-mutagenesis MUTANTS
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Effects of 3 months of full-court and half-court street basketball training on health profile in untrained men 被引量:5
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作者 Morten B.Randers Marie Hagman +4 位作者 Jonathan Brix Jesper F.Christensen Mogens T.Pedersen Jens J.Nielsen Peter Krustrup 《Journal of Sport and Health Science》 SCIE 2018年第2期132-138,共7页
Purpose: The aim of the present study was to investigate whether street basketball organized as 3 v 3 on either a half court(HC) with 1 basket or a full court(FC) with 2 baskets could improve fitness and health profil... Purpose: The aim of the present study was to investigate whether street basketball organized as 3 v 3 on either a half court(HC) with 1 basket or a full court(FC) with 2 baskets could improve fitness and health profiles of untrained men after 3 months of supervised training.Methods: Thirty-five untrained men(aged 20—42 years) completed the pre-and post-intervention testing(FC: n = 13, HC: n = 12, CO(control):n = 10). The training attendance was 2.0 ± 0.4 and 1.9 ± 0.3 times per week in FC and HC, respectively. Mean heart rate(HR) was 83.8 ± 6.0 percent of maximal heart rate(%HR_(max)) and 84.5 ± 2.9 %HR_(max) in FC and HC, respectively.Results: The 3 months of street basketball training on an FC with 2 baskets increased maximal oxygen uptake(2.4 mL/min/kg(95% confidence interval(CI): 1.0—3.9)), time to exhaustion(47 s(95%CI: 26—67)), lean body mass(0.8 kg(95%CI: 0.1—1.5)), and bone mineral density(0.021 g/cm^2(95%CI: 0.011—0.031)), whereas mean arterial pressure(—5.6 mm Hg(95%CI: —7.5 to 3.7)), body fat percentage(—1.6%,(95%CI: —2.5 to —0.7)), heart rate(—18 bpm(95%CI: —24 to —12)), and blood lactate(median: —1.4 mmol/L(interquartile range: —1.5 to —0.6)) during submaximal running were lowered. The changes were less pronounced after the training period when playing on an HC with 1 basket, but increases in maximal oxygen uptake(1.6 mL/min/kg(95%CI: —0.1 to 3.3)), time to exhaustion(28 s(95%CI: 9—47)), lean body mass(1.3 kg(95%CI: 0.3—2.4)), and lower body fat percentage(—0.9%(95%CI: —1.9 to —0.1)) were observed in this group.Conclusion: Three months of 3 v 3 street basketball training improved fitness and led to broad-spectrum improvements in variables related to overall health profile, with the most marked effects observed when playing on an FC with 2 baskets. 展开更多
关键词 Blood pressure Body composition Cardiovascular fitness Maximal oxygen uptake Muscoloskeletal fitness Physical demands Small-sided games Team sport
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Microbial Biomass Carbon Trends in Black and Red Soils Under Single Straw Application: Effect of Straw Placement, Mineral N Addition and Tillage 被引量:27
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作者 J. CHILIMA, HUANG CHANGYONG and WU CIFANG College of Natural Resources and Environment, Zhejiang University, Hangzhou 310029 (China) 《Pedosphere》 SCIE CAS CSCD 2002年第1期59-72,共14页
Quantifying trends in soil microbial biomass carbon (SMBC) undercontrasting management conditions is important in understanding thedynamics of soil organic matter (SOM) in soils and in ensuring theirsustainable use. A... Quantifying trends in soil microbial biomass carbon (SMBC) undercontrasting management conditions is important in understanding thedynamics of soil organic matter (SOM) in soils and in ensuring theirsustainable use. Against such a background, a 60-day greenhousesimulation experiment was carried out to study the effects of strawplacement, mineral N source, and tillage on SMBC dynamics in twocontrasting soils, red sol (Ferrasol) and black soil (Acrisol). Thetreatments included straw addition + buried (T1); straw addition +mineral N (T2); and straw addition + tillage (T3). 展开更多
关键词 microibla biomass carobn mineral N soil straw placement TILLAGE
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Combining Ridge with No-Tillage in Lowland Rice-Based Cropping System: Long-Term Effect on Soil and Rice Yield 被引量:18
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作者 JIANG Xian-Jun2 and XIE De-Ti College of Resources and Environment, Southwest University, 216 Tiansheng Road, Beibei, Chongqing 400716 (China) 《Pedosphere》 SCIE CAS CSCD 2009年第4期515-522,共8页
A tillage method of combining ridge with no-tillage (RNT) was employed in lowland rice-based cropping system to study the long-term effects of RNT on soil profile pattern, soil water stable aggregate distribution, nut... A tillage method of combining ridge with no-tillage (RNT) was employed in lowland rice-based cropping system to study the long-term effects of RNT on soil profile pattern, soil water stable aggregate distribution, nutrients stratification and yields of rice and post-rice crops. After flooded paddy field (FPF) was practiced with RNT for a long time, soil profile changed from G to A-P-G, and horizon G was shifted to a deeper position in the profile. Also the proportion of macroaggregate (> 2 mm) increased, whereas the proportion of silt and clay (< 0.053 mm) decreased under RNT, indicating a better soil structure that will prevent erosion. RNT helped to control leaching and significantly improved total N, P, K and organic matter in soil. The highest crop yields were found under RNT system every year, and total crop yields were higher under conventional paddy-upland rotation tillage (CR) than under FPF, except in 2003 and 2006 when serious drought occurred. RNT was proven to be a better tillage method for lowland rice-based cropping system. 展开更多
关键词 aggregate-size distribution conservative tillage flooded paddy field soil profile pattern
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Comparisons of the effects of different drying methods on soil nitrogen fractions:Insights into emissions of reactive nitrogen gases(HONO and NO) 被引量:4
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作者 WU Dianming DENG Lingling +7 位作者 LIU Yanzhuo XI Di ZOU Huilan WANG Ruhai SHA Zhimin PAN Yuepeng HOU Lijun LIU Min 《Atmospheric and Oceanic Science Letters》 CSCD 2020年第3期224-231,共8页
Reactive nitrogen(Nr)emission from soils,e.g.,nitrous acid(HONO)and nitric oxide(NO),is a key process of the global nitrogen(N)cycle and has significant implications for atmospheric chemistry.To understand the underly... Reactive nitrogen(Nr)emission from soils,e.g.,nitrous acid(HONO)and nitric oxide(NO),is a key process of the global nitrogen(N)cycle and has significant implications for atmospheric chemistry.To understand the underlying mechanisms of soil Nr emissions,air-dried or oven-dried soils are commonly used in the laboratory.To date,few studies have compared the effects of different drying methods on soil Nr gas fluxes and N fractions.Here,the authors studied soil water content,pH,(in)organic N content,and Nr gas fluxes of air-dried,freeze-dried,oven-dried,and fresh soils from different land-use types.The results showed that the soil pH of air-dried and oven-dried samples was significantly lower compared with fresh soil from farmland and grassland,but higher compared with forest soil.The difference in soil pH between freeze-dried and fresh soil(mean±standard deviation:0.52±0.31)was the lowest.In general,all drying methods increased the soil NH4+-N,NO3−-N,and dissolved organic N contents compared with fresh soil(P<0.05).The maximum HONO and NO flux and total emissions during a full wetting–drying cycle of fresh soil were also increased by air-drying and oven-drying(P<0.001),but comparable with freeze-dried soil(P>0.2).In conclusion,all drying methods should be considered for use in studies on the land–atmosphere interface and biogeochemical N cycling,whereas the freeze-drying method might be better for studies involving the measurement of soil Nr gas fluxes. 展开更多
关键词 FREEZE-DRIED nitrogen cycling NOx soil pH gas flux
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Numerical simulations of water flow and contaminants transport near mining wastes disposed in a fractured rock mass 被引量:10
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作者 Ben Abdelghani Farouk Aubertin Michel +1 位作者 Simon Richard Therrien René 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2015年第1期37-45,共9页
A numerical tool, called Hydro-Geosphere, was used to simulate unsaturated water flow and contaminants migration around an open pit filled with mining wastes. Numerical simulations had been carried out to assess the i... A numerical tool, called Hydro-Geosphere, was used to simulate unsaturated water flow and contaminants migration around an open pit filled with mining wastes. Numerical simulations had been carried out to assess the influence of various factors on water flow and solute transport in and around the surface openings including recharge, properties of the waste material and presence of fractures in the surrounding rock mass. The effect of the regional hydraulic gradient was also investigated. The analyses were conducted by simulating various 2D cases using experimentally obtained material properties and controlled boundary conditions. The effects of the hydrogeological properties of the filling material(i.e., water retention curve and hydraulic conductivity function), fracture network characteristics and conductivity of the joints were assessed. The results illustrate that fractures control water flow and contaminants transport around the waste disposal area. A fracture network can desaturate the system and improve the regional gradient effect. 展开更多
关键词 Hydro-GeosphereNumerical modellingUnsaturated water flowContaminants transportTailingsWaste rocks
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Addition of Urban Waste to Semiarid Degraded Soil:Long-term Effect 被引量:10
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作者 F.BASTIDA J.L.MORENO +1 位作者 C.GARC■A T.HERNNDEZ 《Pedosphere》 SCIE CAS CSCD 2007年第5期557-567,共11页
The addition of municipal solid wastes (MSW) is considered as a possible strategy for soil rehabilitation in southeast Spain. The objective of this study was to evaluate the long-term (17 years) effect of five dos... The addition of municipal solid wastes (MSW) is considered as a possible strategy for soil rehabilitation in southeast Spain. The objective of this study was to evaluate the long-term (17 years) effect of five doses of MSW addition on the microbiological, biochemical, and physical properties of semiarid soil. Increased values of several parameters that serve as indicators of general microbiological activity, such as, basal respiration, adenosine triphosphate (ATP) or dehydrogenase activity; microbial population size (microbial biomass C), and extracellular hydrolase activity related to macronutrient cycles, such as, urease, 3-glucosidase, and N-a-benzoyl-L-argininamide protease, were observed in the amended soils. The highest MSW doses showed the highest values in these hydrolase activities. The incorporation of municipal waste resulted in a more dense development of the plant cover, 50% greater in higher doses than in the control treatment, which generated a substantial increase in several C fractions. Total organic carbon reached 12 g kg^-1 soil with the highest MSW doses, compared to 4.30 g kg^-1 soil in the control treatment. The physical properties of the soil were also improved, showing greater percentage of stable aggregates and water holding capacity. Positive correlation coefficients between C fractions and parameters related to microbial activity and aggregate stability were observed. Although these improvements were greater in the soils receiving the highest doses of organic amendment, the increases were not proportional to the amount added, demonstrating the existence of a threshold, above which an increase in the amount of organic matter added is not reflected in an increase in the soil's physical, biochemical, and microbiological properties. However, the addition of municipal solid wastes proved its suitability for improving soil quality, thereby indicating the potential of such an amendment, to prevent desertification in Mediterranean areas such as those studied. 展开更多
关键词 enzyme activities long-term effect microbial biomass C municipal solid waste RESPIRATION
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