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91.
以石油焦为活性炭原料,运用化学活化法制备了超级电容器用高比表面积活性炭。利用SEM和BET对实验制备的活性炭进行了分析和表征。以实验制备的活性炭为超级电容器电极材料,利用恒流充放电测试对其电容特性进行了研究。结果表明,实验研制的活性炭的比表面积为1674m2/g,中孔含量达到40%,在10mA/cm2的电流密度下其比容达到285F/g,而且基于实验研制的活性炭的超级电容器具有低内阻和良好的功率特性。  相似文献   
92.
The rate of oxidation of peat soils is highly seasonal and varies with temperature and soil moisture content. Large variations in soil moisture content result in wet–dry cycles that can enhance peat degradation. Water‐table management plays a crucial role in controlling and damping the effect of these environmental factors. However, maintaining high ditch water levels in fields bounded by ditches does not guarantee a high field groundwater level. The effect of installing subsurface irrigation at different spacings on water table elevation was studied in a low‐lying peat grassland. The water table elevation data were compared against values predicted with a water balance model. In addition, greenhouse experiments were carried out on undisturbed soil core samples collected from the peat grassland as well as a low‐lying peatland under intensive arable faming to measure CO2 evolution under different water regimes. The field data from the peat grassland suggest that sub‐irrigation spacing as low as 10 m is necessary during summer periods to maintain groundwater levels similar to those in the ditches. Over the same period of observation, the difference in water level between the ditches and the non‐irrigated fields is as high as 0.7 m. Modelled outputs are in good correlation with the field observations, and demonstrate that simple water balance models can provide an effective tool to study the effect of water management practices and potential changes in subsurface conditions, climate and land use on water‐table levels. The measurement of CO2 emission from undisturbed peat soil columns shows that the rate of oxidation of soil organic matter from peat soils is highly seasonal and that drainage exacerbates the rate of peat mineralization.  相似文献   
93.
Abstract. Field margins are a valuable resource in the farmed landscape, providing numerous environmental benefits. We present a preliminary analysis of the carbon mitigation potential of different field margin management options for Great Britain, calculated using data from long-term experiments and literature estimates. The carbon sequestration potential of the individual options investigated here varies from 0.1 to 2.4% of 1990 UK CO2-C emissions, or 0.7–20% of the Quantified Emission Limitation Reduction Commitment (QELRC). The scenarios investigated covered three possible margin widths and options for the management of margins at each width (viz. grass strips, hedgerows and tree strips). Scenarios involving margin widths of 2, 6 or 20 m would require approximately 2.3, 6.7 or 21.3% of the total arable area of Great Britain, respectively. Scenarios including tree strips offered the greatest potential for carbon sequestration, since large amounts would be accumulated in above-ground biomass in addition to that in soil. We also accounted for the possible impacts of changed land management on trace gas fluxes, which indicated that any scenario involving a change from arable to grass strip, hedgerow or tree strip would significantly reduce N2O emissions, and thus further increase carbon mitigation potential. There would also be considerable potential for including the scenarios investigated here with other strategies for the alternative management of UK arable land to identify optimal combinations. We assumed that it would take 50–100 years for soil carbon to reach a new equilibrium following a land use change. More detailed analyses need to be conducted to include environmental benefits, socioeconomic factors and the full system carbon balance.  相似文献   
94.
中国正在不断推进农村绿色经济转型与乡村振兴战略,田园综合体等各种以生态环境为导向的农业开发模式是乡村振兴建设的新途径,驱动农业固碳减排的同时,也带动着传统农业不断向现代农业发展的转变。以EOD(Ecology-Oriented-Development,生态环境导向的开发)模式的上海市金山区枫泾镇郊野村庄田园综合体为研究对象,在现场调研与数据统计的基础上,分析了园区内的碳输入和碳输出以及碳在园内各区域间的流动和储积;同时,根据碳源和碳汇清单和估算结果,分析了田园综合体各区的碳平衡特点。结果显示,上海市金山区郊野村庄田园综合体2021年碳平衡表现为净碳汇区,净碳汇量为152.09 tC,其中排放量为588.79 tC,碳固定量为740.88 tC。田园综合体内,作物种植区通过低碳有机种植模式成为净碳汇量最大的区域,净碳汇量185.76 tC;水产养殖区通过高效的水草多级循环利用模式净碳汇量达62.20 tC;高空间利用率的立体农业区因农肥的碳排放量大表现为碳源区,净碳汇量为-10.81 tC;生产生活区是最大的碳源区,净碳汇量达-85.05 tC,人类文旅活动是其中最大的碳排放源。分析结合该田园综合体的碳流动,提出了发展高物质循环利用率、高空间利用率、低碳有机种植模式和农业科学管理四个农业降碳增汇的方向。  相似文献   
95.
木质原料热解及活性炭结构的研究   总被引:7,自引:0,他引:7  
以椰壳为代表原料进行热解研究,用热重分析法分析了椰壳热分解的机理。与一般木质原料一样,椰壳也是由半纤维素、纤维素和木质素构成,椰壳中的半纤维素的分解温度在200~260℃,纤维素的分解温度在260~295℃,木质素的分解温度在295~320℃。本研究还探讨了椰壳炭的孔结构参数,炭化温度425~720℃,其微孔容积为0.124~O.222mL/g,并用扫描电子显微镜观察了椰壳炭的表面形貌,椰壳在热分解时,细胞壁分解形成了微米级的大孔,并保留了椰壳的纤维状结构。采用离子发射光谱,分析了椰壳炭的微量元素组成,主要有铝、钡、铁、镁、钙、硅等。  相似文献   
96.
We investigated carbon (C) uptake and respiratory losses of an adult Pinus cembra tree at the alpine timberline throughout an entire year by means of an automated, multiplexing gas exchange system. These chamber measurements were then combined with biomass data for scaling up the C budget to the tree level. Integrated over an entire year, the cumulative C gain of the tree under study was 23.5 kg of C in 2002. The daily C balance was negative for 5 months and the estimated total wintertime respiratory losses were 9% of the amount of C fixed during the growing season. The total annual C loss of the tree consumed 55% of the annual net C gain and the remaining surplus was stored in new tissues (36%) and used for fine root growth (9%). Thus, the overall C budget of P. cembra at the upper timberline is balanced fairly well, although the C sink strength in fine roots is strongly limited owing to low root zone temperatures when compared to conifers at lower elevation sites.  相似文献   
97.
地中海山地土壤中团聚体的形成和有机质的储存   总被引:1,自引:0,他引:1  
R. M. POCH  M. ANT&#;NEZ 《土壤圈》2010,20(6):702-710
Soil aggregation and organic matter of soils from the pre-Pyrenean range in Catalonia (NE Spain) were studied, in order to assess their quality as carbon sinks and also to select the best soil management practices to preserve their quality. Aggregate stability, organic carbon and micromorphology were investigated. The highest amount of organic carbon was found in alluvial, deep soils (228 Mg C ha-1), and the lowest was in a shallow, stony soil with a low plant cover (78 Mg C ha-1). Subsurface horizons of degraded soils under pastures were the ones with smaller and less-stable aggregates. Fresh residues of organic matter (OM) were found mostly in interaggregate spaces. Within the aggregates there were some organic remains that were beginning to decompose, and also impregnative nodules of amorphous OM. Although OM was evenly distributed among the aggregate fractions, the larger blocky peds had more specific surface, contained less decomposed OM and had a lower organic/mineral interphase than smaller crumb aggregates, which were also more stable. Soil carbon storage was affected primarily by the OM inputs in the surface horizons. In order to store organic carbon over the mid-and long-term periods, the mechanisms favouring structuration through biological activity and creating small aggregates with intrapedal stable microporosities seemed to be the most effective.  相似文献   
98.
【目的】碳计量参数的研究对科学评价大兴安岭林区森林碳汇功能和价值以及合理制定应对全球气候变化策略具有十分重要意义。【方法】本文以内蒙古大兴安岭地区兴安落叶松人工林为研究对象,利用NPP方法对不同林龄的兴安落叶松人工林生物量碳储量进行测定,依据联合国政府间气候变化专门委员会(IPCC)发布的指南方法,计算兴安落叶松人工林的碳计量参数,并与IPCC提供的生物量碳计量参数进行差异分析,并分析实测碳计量参数与林龄、胸径、林分密度等易测因子的相关性,对比分析NPP法实测碳储量与IPCC法获得碳储量之间的差异。【结果】(1)碳计量参数中除根茎比(R)外,其他的碳计量参数的实测值均大于IPCC缺省值;(2)碳计量参数生物量转化与扩展因子(BCEF)、生物量扩展因子(BEF)和木材基本密度(WD)随林龄、及胸径呈负相关,R则是一个相对稳定的数值。【结论】IPCC指南所给出的生物量碳计量参数值会随着林龄、立地条件、林种等因素发生改变。通过与NPP法计算出来的碳储量对比发现两种方法计算的碳储量差异较大。本研究为进一步校正IPCC中的碳计量参数以及森林碳储量的准确估算提供基础数据。  相似文献   
99.
辽宁省乔木林的碳储量和碳密度研究   总被引:1,自引:0,他引:1  
李宁 《中国农学通报》2022,38(16):27-31
为更好地了解辽宁省森林的碳汇能力,基于森林资源“一张图”数据对乔木林的碳储量和碳密度进行研究。针对乔木林各林种的不同龄组、各龄组的不同林种的碳特征值进行估算和比较分析,进而对辽宁省森林资源的固碳功能进行分析。研究认为,防护林中中龄林碳储量权重最大,面积权重幼龄林最大;特种用途林中成熟林的碳储量权重最大,面积权重成熟林最大;用材林中中龄林的碳储量权重最大,面积权重幼龄林最大;薪炭林中幼龄林的碳储量权重最大,面积权重也是幼龄林最大;幼龄林、中龄林、近熟林、成熟林和过熟林都是防护林的碳储量最高。研究结果可为森林经营管理、环境保护政策的提出等提供数据支撑。  相似文献   
100.
吴志强 《林产工业》2020,57(3):96-98
随着我国对环保的日益重视,以人造板为主要原料的板式家具适应绿色健康发展理念。介绍了板式家具主要材料以及板式家具主要原材料分类,分析了板式家具设计与制造中的减碳技术,为板式家具设计及制造企业能获得更好的社会和经济效益提供参考。  相似文献   
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