活性炭对柴油机尾气吸附机理及其行为研究     

董佳晟  彭樟林  毛勇 《农业装备与车辆工程》2013,(11):61-63

柴油车排放尾气严重污染环境并危害人类健康，其净化技术一直是人们研究的热点问题。基于各种活性炭的尘埃吸附性及气体通透性．研究了不同量活性炭在非催化条件下对尾气的吸附机理及行为。试验结果表明：各种活性炭对柴油机尾气排放物吸附作用较为明显：煤质活性炭对于尾气排放物吸附作用要强于椰壳活性炭碳，且对尾气排放降低程度最大、经济性最好用量在400g左右。  相似文献   

基于P300高性能BCI打字机的研究与实现     

樊恩伯  陈曦 《湖南农业大学学报(自然科学版)》2013,40(4):80-83

利用Gleeble-3800数字控制热/力模拟试验机研究了Q690低碳微合金钢在变形温度850~1150 ℃，应变速率0.01~30 s-1条件下的高温单道次压缩变形行为.建立了基于动态材料模型(DMM)的加工图，结合OM观察变形体微观组织确定了该钢种的高温热变形机制.结果表明：应变量0.7及以下的加工图中包含2个峰区(1 000~1 120 ℃，0.01~0.37 s-1和1 100~1 150 ℃，3.16~30 s-1)和3个加工失稳区(850~900 ℃，0.01~0.32 s-1和850~900 ℃，10~30 s-1以及1 000~1 085 ℃，1~30 s-1).应变量超过0.8的加工图包含2个峰区(1 025~1 100 ℃，0.01~0.38 s-1和1 100~1 150 ℃，3~30 s-1)，失稳区为低温(850~900 ℃，0.01~30 s-1)以及应变速率1 s-1以上的中低温度(850~1 100 ℃)范围，在这两个峰区峰值点附近的热变形显微组织为均匀的完全动态再结晶组织，因此，这两个区域均适合Q690钢的热加工变形.  相似文献   

Investigations on the radioactive contamination of crop plants as a result of H-bomb detonation (Part 2) Root and foliage uptake of “Bikini ash”     

Shingo Mitsui  Sueo Aso  Kiyoshi Tensho  Kikuo Kumazawa 《Soil Science and Plant Nutrition》2013,59(1):17-18

The Foliar Uptake by Squash Plant

The radioactive ash for experimental use, hereafter referred to as “Bikini ash”, was prepared by igniting the heavily contaminated substances on board No. 5 Fukuryu Maru at about 650°C, followed by sifting through a 100 mesh sieve. On ignition some parts of the fission products, particularly iodine, ruthenium and tellurium would have possibly been lost to the air.  相似文献   

Short and long‐term distribution with depth of soil organic carbon and nutrients under traditional and conservation tillage in a Mediterranean environment (southwest Spain)     

R. López‐Garrido  E. Madejón  J. M. Murillo  F. Moreno 《Soil Use and Management》2011,27(2):177-185

The impacts of tillage and cropping sequences on soil organic matter and nutrients have been frequently reported to affect the uppermost soil layers, but there is little published information concerning effects at greater depth. This article reports results on the distribution of soil organic carbon (SOC), active carbon (AC), N, Olsen‐P and extractable K within 100 cm in short (4 yr) and long (16 yr) term experiments under different tillage systems. Short (TT₄) and long (TT₁₆) traditional tillage are compared with conservation tillage, reduced (RT₁₆) and non‐tillage (NT₄). The results show more accumulation of SOC in the near‐surface under RT₁₆ and NT₄ in both experiments compared with traditional tillage. Moreover, greater C content occurs to 40 cm depth in the long‐term experiment. The results demonstrate the importance of time on C accumulation, not only in near‐surface layers but also at greater depths. Active C is an indicator of the increase in soil quality in the long‐term experiment. This trend is only apparent for the first 10 cm in the short‐term experiment. Patterns in N, Olsen‐P and extractable K are similar to that of SOC. However, only extractable K is significantly greater in soil under conservation tillage (RT₁₆ and NT₄) after short and long periods. Potassium availability is a good indicator of the changes caused by tillage. Our results indicate that studies of soils at depth could be very useful in long‐term experiments to demonstrate the effect of conservation tillage on C and nutrient distribution.  相似文献   

Potential carbon stock in Japanese forest soils – simulated impact of forest management and climate change using the CENTURY model     

S. Hashimoto  S. Ugawa  K. Morisada  M. Wattenbach  P. Smith  Y. Matsuura 《Soil Use and Management》2012,28(1):45-53

Forest management and climate change may have a substantial impact on future soil organic carbon (SOC) stocks at the country scale. Potential SOC in Japanese forest soils was regionally estimated under nine forest managements and a climate change scenario using the CENTURY ecosystem model. Three rotations (30, 50, 100 yr) and three thinning regimes were tested: no‐thinning; 30% of the trees cut in the middle of the rotation (e.g. 15 year in a 30‐yr rotation) and thinned trees all left as litter or slash (ThinLef) and the trees from thinning removed from the forest (ThinRem). A climate change scenario was tested (ca. 3 °C increase in air temperature and 9% increase in precipitation). The model was run at 1 km resolution using climate, vegetation and soil databases. The estimated SOC stock ranged from 1600 to 1830 TgC (from 6800 to 7800 gC/m²), and the SOC stock was largest with the longest rotation and was largest under ThinLef with all three rotations. Despite an increase in net primary production, the SOC stock decreased by 5% under the climate change scenario.  相似文献   

Effect of Water and Rice Straw Management Practices on Soil Organic Carbon Stocks in a Double-Cropped Paddy Field     

《Communications in Soil Science and Plant Analysis》2012,43(18):2330-2342

ABSTRACT

Water and rice straw (RS) management practices can potentially affect the accumulation of soil organic carbon (SOC) in agricultural soils. Field experiments were conducted in two consecutive rice-growing seasons (wet and dry) to evaluate SOC stocks under different water (continuous flooding [CF], alternate wetting and drying [AWD]) and RS management practices (RS incorporation [RS-I], RS burning [RS-B], without RS incorporation and burning [WRS]) in a double-cropped paddy field. RS-I under AWD had higher volumetric water content than the same RS management under CF at tillering in both growing seasons. Total SOC was significantly higher under AWD at tillering in both wet and dry seasons and after harvesting in the dry season compared with CF. The same trend was also observed for C:N ratio at tillering and after harvesting in the dry season. RS-B plots had lower SOC stocks than RS-I and WRS plots across most of the measuring periods regardless of the growing seasons. SOC stocks were 33.09 and 39.31 Mg/ha at RS-B and RS-I plots, respectively, in the wet season, whereas the respective values were 21.45 and 24.55 Mg/ha in the dry season. Incorporation of RS enhanced SOC stocks under AWD irrigation, especially in the dry season before planting. Soil incorporation of RS in combination with AWD could be a viable option to increase SOC stocks in the double-cropped rice production region as it is strongly linked with soil fertility and productivity. However, the environmental consequences of RS incorporation in irrigated lowland rice production system should be taken into consideration before its recommendation for paddy field on a large scale.  相似文献   

二氧化碳输送管道关键技术研究现状     

李昕 《油气储运》2013,32(4):343-348

碳捕集与封存作为减少温室气体排放的重要手段成为全球研究热点，管道运输是该技术得以实施的关键环节。当CO2处于超临界或密相状态时，其具有液体的密度、气体的粘性和压缩性，对于管道运输是最有效率的。由于管输CO2的特殊性质，CO2输送管道与碳氢化合物输送管道存在不同；由于海洋环境的复杂性，CO2海上输送管道与陆地输送管道存在不同。系统总结了实现CO2管道输送需要解决的关键技术问题，着重介绍了CO2输送管道流动保障和延性断裂扩展领域的研究进展，指出CCS作为大规模减少温室气体排放的重要选项，开展与之相关的基础研究十分迫切。（图3，参44）  相似文献   

我国橡胶林碳汇贸易潜力的实证分析     

魏宏杰  刘锐金  杨琳 《热带作物学报》2012,32(5):81-86

依据气候减缓项目选择可贸易的碳库，利用森林蓄积量扩展法，计算了2008年和2011年橡胶林碳汇量，进而以2011年为基期，测算了2015年我国橡胶林的碳汇贸易潜力。计算结果表明，到2015年，我国橡胶林碳汇贸易潜力为248.61万t，占现有碳储量的10.62%，碳汇量年均增长速度呈下降趋势，显示出我国橡胶林碳汇贸易潜力的后劲不足。最后提出了依靠内涵式增长途径来提升碳汇潜力的几点建议。  相似文献   

Soil Organic Carbon,Biochar, and Applicable Research Results for Increasing Farm Productivity under Australian Agricultural Conditions     

《Communications in Soil Science and Plant Analysis》2012,43(10):1187-1199

The conversion of vegetative biomass waste to biochar (biologically derived charcoal) is a source of carbon (C) that can be used to increase the level of soil organic C (SOC) in agricultural soils. This review collates available research into the effects of biologically derived C species with respect to the direct and indirect effects on agricultural productivity and their potential for use in Western Australian agricultural systems. There is a growing requirement to quantify the effect of specific biochar applications for agroecological purposes and to verify biosequestered C for climate-change-mitigation activities. This work provides a review and assessment of safe biochar application rates and examines the present levels of scientific uncertainty surrounding the efficacy and reliability of applying biochar to soils in relation to crop productivity.  相似文献   

Above and Below Ground Measurements of Greenhouse Gases from Swine Effluent Amended Soil     

《Communications in Soil Science and Plant Analysis》2012,43(17-18):2479-2503

Abstract

As a means of economic disposal and to reduce need for chemical fertilizer, waste generated from swine production is often applied to agricultural land. However, there remain many environmental concerns about this practice. Two such concerns, contribution to the greenhouse effect and stratospheric ozone depletion by gases emitted from waste‐amended soils, have not been thoroughly investigated. An intact core study at Auburn University (32 36′N, 85 36′W) was conducted to determine the source‐sink relationship of three greenhouse gases in three Alabama soils (Black Belt, Coastal Plain, and Appalachian Plateau regions) amended with swine waste effluent. Soil cores were arranged in a completely random design, and treatments used for each soil type consisted of a control, a swine effluent amendment (112 kg N ha^?1), and an ammonium nitrate (NH₄NO₃) fertilizer amendment (112 kg N ha^?1). During a 2‐year period, a closed‐chamber technique was used to determine rates of emission of nitrous oxide (N₂O)–nitrogen (N), carbon dioxide (CO₂)–carbon (C), and methane (CH₄)–C from the soil surface. Gas probes inserted into the soil cores were used to determine concentrations of N₂O‐N and CO₂‐C from depths of 5, 15, and 25 cm. Soil water was collected from each depth using microlysimeters at the time of gas collection to determine soil‐solution N status. Application of swine effluent had an immediate effect on emissions of N₂O‐N, CO₂‐C, and CH₄‐C from all soil textures. However, greatest cumulative emissions and highest peak rates of emission of all three trace gases, directly following effluent applications, were most commonly observed from sandier textured Coastal Plain and Appalachian Plateau soils, as compared to heavier textured Black Belt soil. When considering greenhouse gas emission potential, soil type should be a determining factor for selection of swine effluent waste disposal sites in Alabama.  相似文献