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可控碳改性Pd/TiO2用于直接合成双氧水:非均相界面对催化性能的影响 预览
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作者 严伟 孙睿 +5 位作者 李蒙 李力成 杨祝红 花泽林 陆小华 刘畅 《催化学报》 SCIE EI CAS CSCD 北大核心 2020年第2期312-321,共10页
双氧水(H2O2)是一种重要的绿色氧化剂,广泛应用于纺织、医疗、废水处理、军事等重要领域.目前, H2O2的工业生产以蒽醌法为主,该法设备投资大、运行成本高,同时工艺涉及大量的有机溶液,活性中间体蒽醌也会发生缓慢降解,产生有毒副产物.... 双氧水(H2O2)是一种重要的绿色氧化剂,广泛应用于纺织、医疗、废水处理、军事等重要领域.目前, H2O2的工业生产以蒽醌法为主,该法设备投资大、运行成本高,同时工艺涉及大量的有机溶液,活性中间体蒽醌也会发生缓慢降解,产生有毒副产物.与蒽醌法相比,通过负载型贵金属催化剂催化H2与O2反应直接合成H2O2,过程绿色环保且生产工艺简单,引起了各界广泛关注.然而,从热力学上分析, H2和O2更容易反应生成H2O, H2O2只是该反应的中间产物,会继续发生加氢和直接分解反应生成H2O,导致H2和O2的低效利用,开发高H2O2选择性且高反应效率的催化剂已成为氢氧直接合成H2O2研究的重点与难点.目前大部分研究策略旨在通过调控或影响反应中心结构、价态来抑制H2O2的副反应,进而提升H2O2的选择性和反应效率;尽管已取得了良好的进展,但仍需发展新的调控策略来满足工业应用的要求.本课题组前期研究表明,促使H2O2从催化剂上脱附可以有效地提升H2O2的选择性和产率.相比于针对反应中心的调控,不稳定的H2O2从催化剂上快速脱附同样起到抑制H2O2参与副反应的作用.为此,本文提出一种炭量可控的非均一界面改性方法,以常规的Pd/TiO2作为研究对象,借助各种结构表征,发现炭物种在TiO2表面呈非均一分散状态,而且改性对于催化剂的几何结构影响较小;另外,催化剂表面的疏水性会随着碳含量的增加而增加,导致其与H2O2间的吸附能相应变小.反应结果显示,表面非均一的炭化改性技术可以显著提升Pd/TiO2催化剂的H2O2选择性和产率.通过构效关系分析,可知这种改性技术可以保持Pd颗粒与TiO2间相互作用的同时,还可以促进H2O2的快速脱附,进而提升改性Pd/TiO2催化剂的H2O2直接合成效率.该改性方法简单、易控,可拓展应用到其他类型催化剂的H2O2直接合成性能调控与改进. 展开更多
关键词 H2O2直接合成 二氧化钛 非均一界面改性
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碳对镍基单晶高温合金凝固缺陷影响的研究进展 预览
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作者 王晓娟 刘林 +5 位作者 黄太文 杨文超 岳全召 霍苗 张军 傅恒志 《材料导报》 EI CAS CSCD 北大核心 2020年第3期148-156,共9页
镍基单晶高温合金因优异的高温力学性能而被广泛应用于先进航空发动机的涡轮叶片和导向叶片等热端部件中。近几十年来,随着单晶高温合金的发展,合金代次已由最初的第一代发展到第五代。在单晶高温合金逐代更替的过程中,一方面微量元素... 镍基单晶高温合金因优异的高温力学性能而被广泛应用于先进航空发动机的涡轮叶片和导向叶片等热端部件中。近几十年来,随着单晶高温合金的发展,合金代次已由最初的第一代发展到第五代。在单晶高温合金逐代更替的过程中,一方面微量元素碳由最初的完全去除发展到后来的限量使用,另一方面难熔元素(W、Mo、Ta和Re)的加入量逐渐增加。这是因为碳的加入可以减少氧化物,提高合金的纯净度,改善合金的可铸性,其主要的作用是控制由难熔元素增加所引起的雀斑、缩松、杂晶和小角度晶界等凝固组织缺陷。目前,碳对镍基单晶高温合金中凝固缺陷影响的研究取得了一些进展,但也存在一定问题。研究表明雀斑的形成是糊状区液态金属流动所导致的枝晶生长停滞或枝晶熔断,通过碳的添加减缓液态金属流动以抑制雀斑的形成,但这一研究仅停留在定性阶段,在定量上仅有一些经验公式和判据,关于碳化物在糊状区的析出时间与析出量如何影响热质流动的证据欠缺,需进一步完善。研究发现缩松是凝固过程中固相和液相收缩率不同所引起的枝晶间的微小熔池,碳添加形成的适量碳化物可以通过后期生长填补枝晶间的孔洞以减少缩松,但此研究也只停留在实验现象和笼统的定性说明阶段,具体到碳化物添加量和缩松含量之间的关系还没有明确的规律,还需要深入探究。杂晶的形成与枝晶碎片、模壁过冷形核和籽晶回熔有关,碳的添加可以抑制热质流动,减少枝晶碎片,降低过冷形核,避免杂晶生成。小角度晶界的产生是由于枝晶弯曲和扭转变形,与热质流动无关,微量元素碳的添加虽然不能阻止这类缺陷出现,但可以起到晶界强化作用。目前,碳对杂晶和小角度晶界的影响无论从实验现象还是机理分析都非常欠缺,需要系统地进行研究。本文综述了碳对镍基单晶� 展开更多
关键词 镍基单晶高温合金 凝固缺陷
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Characteristics of carbonaceous aerosols analyzed using a multiwavelength thermal/optical carbon analyzer: A case study in Lanzhou City
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作者 Yulan ZHANG Shichang KANG 《中国科学:地球科学英文版》 SCIE EI CAS CSCD 2019年第2期389-402,共14页
Characteristics of atmospheric carbonaceous aerosols in Lanzhou City from December 2014 to November 2015 are analyzed using a multiwavelength thermal/optical carbon analyzer. Results reveal that average concentrations... Characteristics of atmospheric carbonaceous aerosols in Lanzhou City from December 2014 to November 2015 are analyzed using a multiwavelength thermal/optical carbon analyzer. Results reveal that average concentrations of black carbon (BC) and organic carbon in atmospheric aerosols at Lanzhou are 6.7 and 25.4 μg m-3, respectively, showing obvious seasonality (higher in winter and lower in summer). This is consistent with findings in cities of northern China. Primary organic aerosols and secondary organic aerosols respectively account for approximately 60% and 17% of carbonaceous aerosols. No significant seasonality is found for secondary organic carbon, indicating that its potential sources do not vary significantly throughout the study period. The mass absorption cross-section (MAC632nm) of BC is 7.1 m2g-1, slightly higher than that of immediately emitted BC. MAC values of BC at different wavelengths vary drastically;they are higher for ultraviolet and visible light (8.5–10.2 m2g-1) than for near-infrared light (4.9–5.7 m2g-1). The aerosol absorption optical depth generally declines from the near-infrared to the near-ultraviolet region. The values are higher in winter than in summer, thus showing there are different contributions of BC deposition in different seasons. Brown carbon (BrC) has an ?ngstr?m absorption exponent (AAE) value of approximately 2.75, which is similar to the AAE value of BrC generated by diesel combustion (2.3). The contribution of BrC to light absorption is as much as 34% at a wavelength of 635 nm. This study demonstrates that the multiwavelength thermal/optical carbon analyzer can quantify absorption properties of BrC in atmospheric aerosols. This can enhance understanding of carbonaceous aerosols and provide key parameters for simulations of climate models. 展开更多
关键词 CARBONACEOUS aerosol Black CARBON Organic CARBON BROWN CARBON MULTIWAVELENGTH thermal/optical CARBON ANALYZER
大气圈碳热氧平衡系统工程技术研究 预览
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作者 雷学军 《中国能源》 2019年第9期5-19,共15页
工业化以来,人类大量地开采使用化石燃料,向大气中排放了海量的CO2及CO2当量物质,释放了大量的热量,消耗了大量的O2,打破了大气圈碳热氧的平衡状态,使温室效应显著增强,导致全球气候变暖、臭氧穿洞、冰川融化、海面上升、海啸增多、风... 工业化以来,人类大量地开采使用化石燃料,向大气中排放了海量的CO2及CO2当量物质,释放了大量的热量,消耗了大量的O2,打破了大气圈碳热氧的平衡状态,使温室效应显著增强,导致全球气候变暖、臭氧穿洞、冰川融化、海面上升、海啸增多、风暴升级、陆地缩小、沙漠扩张、土地干旱、粮食减产、森林火灾、灰霾肆虐、物种消失和生态失衡等一系列因环境遭受破坏而造成的极端气候灾难。目前,国内外广泛推行低碳经济和节能减排(主要是减少CO2的排放),忽视了化石能源燃烧释热耗氧的问题。本文对“碳汇草技术”与“减排减碳方法”进行了系统的科学研究,证实了“碳汇草技术”对大气圈碳热氧的平衡作用比林业碳汇、CCS、生物质能发电、风能发电、水能发电、太阳能发电、海洋能发电、地热能发电、天然气发电、核能发电、SAM和TPX等方法更生态、更环保、更经济、更安全、更合理、更优良。 展开更多
关键词 碳热氧平衡 碳汇草技术 减排减碳方法 系统工程 技术研究
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新疆尾闾盐湖滨岸盐碱土中碳酸盐的固碳效应及影响因素 预览
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作者 张芳 熊黑钢 张兆永 《农业工程学报》 EI CAS CSCD 北大核心 2019年第2期122-127,共6页
土壤碳酸盐对现代大气CO2的截存与土壤中的硅酸盐矿物组成、盐基元素供给、有机碳含量等因子密切相关。该文结合土壤理化性质和碳同位素分馏特性,以新疆艾比湖为例,探讨了干旱区尾闾盐湖滨岸盐碱土中碳酸盐的固碳效应和影响因素,研究结... 土壤碳酸盐对现代大气CO2的截存与土壤中的硅酸盐矿物组成、盐基元素供给、有机碳含量等因子密切相关。该文结合土壤理化性质和碳同位素分馏特性,以新疆艾比湖为例,探讨了干旱区尾闾盐湖滨岸盐碱土中碳酸盐的固碳效应和影响因素,研究结果表明:1)土壤碳酸盐是干旱区最重要的碳库,艾比湖滨岸土壤碳酸盐的平均碳密度是有机碳的4.05倍;2)艾比湖滨岸盐碱土中的δ^13CSCC介于-7.9‰~0.3‰之间,δ^13CSCC与HCO3^-存在良好的线性负相关关系,决定系数高达0.6699,大气碳以重碳酸盐形式存在是次生碳酸盐淀积的关键环节之一;3)土壤δ^13CSCC值与硅酸盐矿物阳起石、绿泥石、伊利石存在着良好的线性负相关关系,δ^13CSCC值随着富Ca、Mg、Fe矿物的含量增加明显向负向漂移;4)土壤中有机碳含量越高,生物风化过程越强烈时,δ^13CSCC负向漂移越大,土壤碳酸盐截存较多大气中的轻碳;当土壤含盐量超过一定程度时,有机过程受到抑制,土壤碳酸盐则截存较多大气中的重碳。因此,干旱区存在着有机-无机耦合固碳效应,提高干旱区植被覆盖,可以增加有机碳库储量,同时,经有机过程分馏转移到土壤中的CO2可进一步促进土壤硅酸盐矿物风化,使这部分CO2不再返回大气,而是以碳酸盐形式被长久固存。 展开更多
关键词 土壤 生态 干旱区尾闾盐湖 成土碳酸盐 碳稳定同位素 分馏固碳效应
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Influence of the biological carbon pump effect on the sources and deposition of organic matter in Fuxian Lake,a deep oligotrophic lake in southwest China
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作者 Haibo He Zaihua Liu +5 位作者 Chongying Chen Yu Wei Qian Bao Hailong Sun Yundi Hu Hao Yan 《中国地球化学学报:英文版》 CSCD 2019年第5期613-626,共14页
Biological carbon pumping(BCP)is a key process in which dissolved inorganic carbon in terrestrial aquatic ecosystems is utilized by aquatic autotrophs for photosynthesis and transformed into autochthonous organic matt... Biological carbon pumping(BCP)is a key process in which dissolved inorganic carbon in terrestrial aquatic ecosystems is utilized by aquatic autotrophs for photosynthesis and transformed into autochthonous organic matter(AOC).However,the mechanisms underlying BCP and the amount of generated AOC deposited effectively,are still poorly understood.Therefore,we conducted a systematic study combining modern hydrochemical monitoring and a sediment trap experiment in Fuxian Lake(Yunnan,SW China),the second-deepest plateau,oligotrophic freshwater lake in China.Temperature,pH,EC(electrical conductivity),DO(dissolved O2),[HCO3^-],[Ca^2+],SIc,partial CO2(pCO2)pressure,and carbon isotopic compositions of HCO3^-(δ^13CDIc)in water from Fuxian Lake all displayed distinct seasonal and vertical variations.This was especially apparent in an inverse correlation between pCO2 and DO,indicating that variations of hydrochemistry in the lake water were mainly controlled by the metabolism of the aquatic phototrophs.Furthermore,the lowest C/N ratios and highestδ^13Corg were recorded in the trap sediments.Analyses of the C/N ratio demonstrated that the proportions of AOC ranged from 30%to 100%of all OC,indicating that AOC was an important contributor to sedimentary organic matter(OC).It was calculated that the AOC flux in Fuxian Lake was 20.43 t C km^-2 in 2017.Therefore,AOC produced by carbonate weathering and aquatic photosynthesis could potentially be a significant carbon sink and may have an important contribution to solving the lack of carbon sinks in the global carbon cycle. 展开更多
关键词 Carbonate weathering Hydrochemical variation BIOLOGICAL CARBON PUMP EFFECT Sediment trap AUTOCHTHONOUS organic CARBON CARBON sink
The Carbon Effects of the Urban Ecological Recreational System Based on Systems Simulation 预览
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作者 Hua LI Helong TONG Xiaoxiang WANG 《系统科学与信息学报:英文版》 CSCD 2019年第2期134-147,共14页
As a major component of urban ecological systems, the urban ecological space is an important carbon pool in the urban carbon circulation. Meanwhile, its special recreational function adds to the complexity of its carb... As a major component of urban ecological systems, the urban ecological space is an important carbon pool in the urban carbon circulation. Meanwhile, its special recreational function adds to the complexity of its carbon effects. According to the carbon process and effects of the urban ecological recreational system, the Source-Leakage-Sink-Order(SLSO) framework is proposed as the basis of the four subsystems of the system model. Consisting of 63 parameters, the system dynamics model of urban ecological recreational system is constructed by using VENSIM PLE. Then the urban ecological recreational system in Shanghai under different scenarios is simulated, and the carbon sources and sinks of the system as well as the process of carbon effects such as carbon footprints are analyzed and predicted. Research shows that due to the imbalance of the spatial pattern of ecological recreational space, the carbon sink effects of the system are quite limited. The human carbon source is the main contributor of the system’s carbon sources and the carbon footprint deficit is striking. The management ability of ecological recreational space influences the carbon sink potentials of the system. In addition,the maintenance mode of ecological green space plays a non-trivial role in the composition of carbon sources. 展开更多
关键词 URBAN ECOLOGICAL RECREATIONAL SYSTEM URBAN ECOLOGICAL space CARBON EFFECTS CARBON sinks CARBON sources
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Carbon Storage and Distribution of the Mature Pinus massoniana Plantation in Northwest Guangxi 预览
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作者 Zhenge HUANG Minyang XIE +4 位作者 Mingbao WEI Bin HE Shaozhuang MO Gang ZHOU Ji LIANG 《农业生物技术:英文版》 CAS 2019年第3期141-144,共4页
[Objectives]This study was conducted to understand the carbon sequestration function of mature Pinus massoniana plantation in northwest Guangxi.[Methods]The carbon storage and distribution in a 26-year-old P.massonian... [Objectives]This study was conducted to understand the carbon sequestration function of mature Pinus massoniana plantation in northwest Guangxi.[Methods]The carbon storage and distribution in a 26-year-old P.massoniana plantation were investigated through biomass harvesting in Shankou Forestry Farm of Nandan County,Guangxi Province.[Results]The average carbon content of P.massoniana was 489.3 g/kg,and the carbon contents of different organs ranked from large to small as pine needles > trunks > trunk bark > roots > branches.The carbon contents of understory shrub layer,herb layer and litter layer were 453.0,425.6 and 482.5 g/kg,respectively.The soil organic carbon content in forestland varied from 6.20 to 32.15 g/kg,decreasing with the depth of the soil layer.The carbon storage of the mature P.massoniana plantation ecosystem was 232.13 t/hm^2,of which the tree layer,shrub layer,herb layer,litter layer and soil layer were 92.67,1.36,1.12 and 134.49 t/hm^2,respectively,which accounted for 39.92%,0.59%,0.48%,1.07% and 57.94% of the carbon storage of the whole ecosystem,respectively.The annual net productivity of the tree layer of the mature P.massoniana plantation was 10.36 t/(hm^2·a),the annual net carbon sequestration was 5.41 t/(hm^2·a),and the annual net CO2 absorption was 19.83 t/(hm^2·a).[Conclusions]This study provides basic data and scientific basis for rational evaluation of the ecological benefits of P.massoniana plantation in this area. 展开更多
关键词 PINUS massoniana MATURE FOREST CARBON CONTENT CARBON STORAGE
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Terrestrial dissolved organic carbon consumption by heterotrophic bacterioplankton in the Huanghe River estuary during water and sediment regulation 预览
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作者 ZHANG Mingliang YU Guanglei +4 位作者 WANG Fei LI Bin HAN Huizong QI Zhanhui WANG Tengteng 《海洋湖沼学报(英文)》 SCIE CAS CSCD 2019年第3期1062-1070,共9页
Nearly 20%–50% of the annual terrestrial dissolved organic carbon(DOC)from the Huanghe(Yellow)River was transported to the estuary during the 5-14d of water and sediment regulation.The concentration of DOC increased ... Nearly 20%–50% of the annual terrestrial dissolved organic carbon(DOC)from the Huanghe(Yellow)River was transported to the estuary during the 5-14d of water and sediment regulation.The concentration of DOC increased sharply during the period of water and sediment regulation,which may promote the terrestrial DOC consumption by heterotrophic bacterioplankton.Water and sediment regulation provides an ideal condition for the study of terrestrial DOC consumption by heterotrophic bacterioplankton when terrestrial DOC increases sharply in rainy season,which may help to seek the fates of terrestrial DOC in the estuaries and coasts.In this study,the concentration and stable isotope of DOC,the biomass,growth,and respiration of heterotrophic bacterioplankton were determined.By the study,we found both average percent contribution of terrestrial DOC to the DOC pool and Contribution of terrestrial DOC to the carbon composition of heterotrophic bacterioplankton decreased as distance from the river mouth increased off shore,which was deceased from(39.2±4.0)%,(37.5±4.3)%to(30.3±3.9)%,(28.2±3.9)%respectively.255-484μg C/(L·d)terrestrial DOC was consumed by heterotrophic bacterioplankton.And 29%-45%terrestrial DOC consumed by heterotrophic bacterioplankton releasing as CO2 by respiration.Comparing with tropical estuary,terrestrial DOC consumed by heterotrophic bacterioplankton was lower in temperate estuary(this study).Temperature may limit the consumption of terrestrial DOC by heterotrophic bacterioplankton. 展开更多
关键词 TERRESTRIAL dissolved organic CARBON HETEROTROPHIC BACTERIOPLANKTON CARBON stable ISOTOPE BIOGEOCHEMICAL cycles
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A global carbon market?
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作者 Michael G. POLLITT 《工程管理前沿:英文版》 2019年第1期5-18,共14页
This paper explores the prospects for a global carbon market as the centerpiece of any serious attempt to reach the ambitious goal for greenhouse gas (GHG) reductions set by climate scientists. My aim is to clarify th... This paper explores the prospects for a global carbon market as the centerpiece of any serious attempt to reach the ambitious goal for greenhouse gas (GHG) reductions set by climate scientists. My aim is to clarify the extent to which we know what policy might best support global decarbonisation. We begin by discussing what we might mean by a global carbon market and its theoretical properties. We then go on to discuss the EU Emissions Trading System experience and the recent experience with the Australian carbon tax. Next, we assess recent carbon market initiatives in the US and in China. My argument is that while establishing the amount of emissions required and dividing it up acceptably between countries requires an enormous scientific and international negotiations effort, the economic instruments to deliver the agreed targets are readily at hand. 展开更多
关键词 CARBON MARKET CARBON TAX EU ETS
掺杂碳封装的Fe/Co基纳米颗粒氧还原催化剂(英文)
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作者 倪保霞 武鲁明 +2 位作者 陈睿 史成香 陈铁红 《中国科学:材料科学(英文版)》 CSCD 2019年第11期1626-1641,共16页
氧还原反应是电化学能量转换和存储装置的重要反应过程,但其反应动力学缓慢,因此开发高效低成本的氧还原催化剂至关重要.目前,包裹过渡金属基纳米颗粒的碳材料因其优异的氧还原催化活性,引起了广泛关注.本文按照金属基纳米颗粒的类别从... 氧还原反应是电化学能量转换和存储装置的重要反应过程,但其反应动力学缓慢,因此开发高效低成本的氧还原催化剂至关重要.目前,包裹过渡金属基纳米颗粒的碳材料因其优异的氧还原催化活性,引起了广泛关注.本文按照金属基纳米颗粒的类别从金属、碳化物、磷化物、氧化物、硫化物以及混合颗粒等六个方面综述了掺杂碳封装的Fe/Co基纳米颗粒氧还原催化剂.催化剂碳基质的结构、纳米颗粒的种类及其分布对催化性能有很大影响,目前这类催化剂在碱性介质中表现出了优异的氧还原活性和稳定性,但在酸性介质中的活性仍需要进一步提高.文章讨论了制备封装型纳米颗粒/碳高效氧还原催化剂过程中存在的挑战,并展望了其发展前景. 展开更多
关键词 Fe/Co based NANOPARTICLES ENCAPSULATION carbon OXYGEN REDUCTION REACTION
Scanning Mode Application of Neutron-Gamma Analysis for Soil Carbon Mapping
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作者 Aleksandr KAVETSKIY Galina YAKUBOVA +4 位作者 Nikolay SARGSYAN Clyde WIKLE Stephen A. PRIOR Henry Allen TORBERT Bryan A. CHIN 《土壤圈:英文版》 SCIE CAS CSCD 2019年第3期334-343,共10页
Soil carbon mapping is extremely useful in assessing the effect of land management practices on soil carbon storage. Applications of neutron-gamma analysis in scanning mode for mapping of soil carbon are discussed. A ... Soil carbon mapping is extremely useful in assessing the effect of land management practices on soil carbon storage. Applications of neutron-gamma analysis in scanning mode for mapping of soil carbon are discussed. A Global Positioning System(GPS) device and softwares required to simultaneously acquire gamma signals and geographical positions during scanning operations were added to an existing measurement system. The reliability of soil carbon measurements in scanning mode was demonstrated to be in agreement with results acquired from static mode. The error analysis indicated that scanning measurements can be conducted with the same accuracy as static measurements in approximately one fourth the time. To obtain results suitable for mapping analogous to traditional chemical analyses(i.e.,± 0.5 in weight percent or ± 0.5 w%), scanning time over a given site should be ca. 15 min using the current measurement system configuration. Based on this measurement time, a reasonable towing speed of 3–5 km h^-1, the necessity for complete site coverage during scanning, the number of sites(within the surveyed field), and the required total measurement time can be estimated. Soil carbon measurements for 28 field sites(total area ca. 2.5 ha) were conducted in ca. 8 h. Based on acquired data,a soil carbon distribution map was constructed utilizing various softwares. The surveyed field area included an asphalt road that had carbon readings higher than the surrounding land. The clarity with which these carbon-rich zones were delineated on the constructed map represents evidence supporting the veracity of this method. Neutron-gamma analysis technology can greatly facilitate timely construction of soil carbon maps. 展开更多
关键词 ArcGIS Google Earth Pro IGOR SCANNING technology SOIL CARBON distribution map SOIL CARBON storage
A ketone-functionalized aromatic saddle as a potential building block for negatively curved carbon nanobelts
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作者 Kwan Yin Cheung Qian Miao 《中国化学快报:英文版》 SCIE CAS CSCD 2019年第8期1506-1508,共3页
A novel ketone-functionalized aromatic saddle consisting of 72 sp^2 carbon atoms is successfully synthesized and unambiguously identified with X-ray crystallography.It can,in principle,be used as a building block for ... A novel ketone-functionalized aromatic saddle consisting of 72 sp^2 carbon atoms is successfully synthesized and unambiguously identified with X-ray crystallography.It can,in principle,be used as a building block for synthesis of negatively curved carbon nanobelts and for a bottom-up approach to negatively curved carbon allotropes. 展开更多
关键词 POLYCYCLIC ARENES Synthesis Negatively curved CARBON ALLOTROPES CARBON NANOBELTS Scholl reaction
Effect of biological activated carbon filter depth and backwashing process on transformation of biofilm community
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作者 Wanqi Qi Weiying Li +3 位作者 Junpeng Zhang Xuan Wu Jie Zhang Wei Zhang 《中国环境科学与工程前沿:英文版》 SCIE EI CAS CSCD 2019年第1期159-169,共11页
The biological activated carbon (BAC) is a popular advanced water treatment to the provision of safe water supply. A bench-scale device was designed to gain a better insight into microbial diversity and community stru... The biological activated carbon (BAC) is a popular advanced water treatment to the provision of safe water supply. A bench-scale device was designed to gain a better insight into microbial diversity and community structure of BAC biofilm by using high-throughput sequencing method. Both samples of BAC biofilm (the first, third and fifth month) and water (inlet water and outlet water of carbon filter, outlet water of backwashing) were analyzed to evaluate the impact of carbon filter depth, running time and backwash process. The results showed that the microbial diversity of biofilm decreased generally with the increase of carbon filter depth and biofilm reached a steady-state at the top layer of BAC after three months' running. Proteobacteria (71.02%-95.61%) was found to be dominant bacteria both in biofilms and water samples. As one of opportunistic pathogen, the Pseudomonas aeruginosa in the outlet water of device (1.20%) was about eight times higher than that in the inlet water of device (0.16%) at the genus level after five-month operation. To maintain the safety of drinking water, the backwash used in this test could significantly remove Sphingobacteria (from 8.69% to 5.09%, p < 0.05) of carbon biofilm. After backwashing, the operational taxonomic units (OTUs) number and the Shannon index decreased significantly (p <0.05) at the bottom of carbon column and we found the Proteobacteria increased by about 10% in all biofilm samples from different filter depth. This study reveals the transformation of BAC biofilm with the impact of running time and backwashing. 展开更多
关键词 Biological activated CARBON BIOFILM COMMUNITY structure CARBON filter DEPTH HIGH-THROUGHPUT SEQUENCING
The Carbon Isotope Fluctuations across the Lower–Middle Jurassic Boundary and the Paleoclimate Changes 预览
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作者 YI Haisheng XIA Guoqing +5 位作者 LI Gaojie YI Fan ZHANG Shuai CAI Zhanhu JIAO Haijing WU Chihua 《地质学报:英文版》 SCIE CAS CSCD 2019年第1期244-245,共2页
The Qiangtang Basin of Tibetan Plateau most widely outcrops marine Jurassic strata in China,even in eastern Asian,and the Jurassic strata and ammonites’occurrence are in favor of researching evolution of paleoceanogr... The Qiangtang Basin of Tibetan Plateau most widely outcrops marine Jurassic strata in China,even in eastern Asian,and the Jurassic strata and ammonites’occurrence are in favor of researching evolution of paleoceanography in the Tethyan region and global stratigraphic comparison.This work focused on the carbon isotope changes across the J I–J 2 boundary in the eastern Tethys region. 展开更多
关键词 CARBON STRATA Plateau marine CARBON most
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Effects of prescribed burning on carbon accumulation in two paired vegetation sites in subtropical China 预览
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作者 Yuanqi Chen Jianbo Cao +2 位作者 Lixia Zhou Feng Li Shenglei Fu 《森林生态系统:英文版》 CSCD 2019年第3期210-218,共9页
Background: Prescribed burning is a common practice of site preparation before afforestation in subtropical forests. However, the effects of prescribed burning on carbon (C) dynamics of an ecosystem are poorly underst... Background: Prescribed burning is a common practice of site preparation before afforestation in subtropical forests. However, the effects of prescribed burning on carbon (C) dynamics of an ecosystem are poorly understood. Therefore, a Eucalyptus urophylla plantation (EU) and a naturally recovered shrubland (NS), each treated with prescribed burning and no burning were examined in subtropical China. Methods: Biomass of trees and shrubs in the 1st, 3nd, 4th, and 6th year after treatments were estimated by quadrat survey and allometric equations. Biomass of herbs and forest floors were estimated by harvest method. Plant biomass C storage was calculated by plant biomass multiplying by its C concentration. Soil organic C (SOC) storage in the 6th year after treatments was estimated by SOC concentration multiplying by soil bulk density and soil volumes. Results: Tree biomass C storage was significantly higher in the burned EU (BEU) than in the unburned EU (UEU) in the 1st year after treatments, yet the difference decreased over time. Conversely, tree biomass C storage was lower in the burned NS (BNS) than in the unburned NS (UNS), although the difference was not significant. However, in the 6th year after treatments, the total plant biomass C storage was 14.56% higher in the BEU than that in the UEU, and 59.93% higher in the BNS than that in the UNS, respectively, although the significant difference was only found between UNS and BNS. In addition, neither SOC storage at 0-20 cm nor ecosystem C storage in either the EU or NS was significantly affected by prescribed burning. Conclusions: Prescribed burning has little impact on overall C storage of forest ecosystems, we consider that prescribed burning may be an option for forest site preparation regarding plant biomass C accumulation. 展开更多
关键词 PRESCRIBED fire REFORESTATION Plant BIOMASS CARBON Soil ORGANIC CARBON FOREST management
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Impact of carbon-based nutrient enhancement on biofiltration performance for drinking water treatment
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作者 Yu Zhao Liz Taylor-Edmonds Robert C. Andrews 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第8期124-131,共8页
Incorporation of a carbon-based nutrient enhancementstrategy for drinking water biofiltration is an attractive option, especially for source waters which contain recalcitrant organics. This study compared biofilters t... Incorporation of a carbon-based nutrient enhancementstrategy for drinking water biofiltration is an attractive option, especially for source waters which contain recalcitrant organics. This study compared biofilters that were operated in parallel and individually enhanced with amino acids(including alanine, phenylalanine, and tryptophan), inulin, and sucrose to increase biomass concentration and promote biodegradation of dissolved organic carbon(DOC) in the source water, including disinfection by-product(DBP) precursors. Biomass activity was characterized by measuring adenosine tri-phosphate(ATP), dissolved oxygen(DO) consumption, and through the use of laccase and esterase enzyme assays. Performance was evaluated in terms of headloss,turbidity, p H, DOC, UV254, and DBP formation potential(DBP FP). The introduction of carbonbased nutrients significantly increased biomass activity, where ATP values peaked at 976 ng/g of filter media, 853 ng/g, and 513 ng/g for amino acids, inulin, and sucrose-spiked biofilters,respectively, while a non-spiked control only reached 104 ng/g. DO utilization by the enhanced biofilters was significantly higher than the control, with a strong correlation between ATP and DO uptake observed for all filters(R~2> 0.74). Laccase and esterase enzyme activities of enhanced biofilters were also elevated(p > 0.05), suggesting greater biodegradation potential. Operational parameters such as headloss development and turbidity control were not impaired by carbon supplementation strategies or an increase in biomass concentration and activity. However, the enhancement strategy did not provide improvement in terms of source water carbon removal(DOC and UV254) or DBP FP when treated filters were compared to a control. 展开更多
关键词 Biological FILTRATION CARBON ENHANCEMENT Biomass DISINFECTION by-products Dissolved organic CARBON
Aerosol light absorption in a coastal city in Southeast China:Temporal variations and implications for brown carbon
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作者 Yuqing Qiu Xin Wu +5 位作者 Yanru Zhang Lingling Xu Youwei Hong Jinsheng Chen Xiaoqiu Chen Junjun Deng 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第6期257-266,共10页
Light-absorbing carbonaceous aerosols including black carbon(BC) and brown carbon(BrC)play significant roles in atmospheric radiative properties. One-year measurements of aerosol light absorption at multi-wavelength w... Light-absorbing carbonaceous aerosols including black carbon(BC) and brown carbon(BrC)play significant roles in atmospheric radiative properties. One-year measurements of aerosol light absorption at multi-wavelength were continuously conducted in Xiamen,southeast of China in 2014 to determine the light absorption properties including absorption coefficients(σabs) and absorption ?ngstr?m exponent(AAE) in the coastal city.Light absorptions of BC and BrC with their contributions to total light absorption were further quantified. Mean σabsat 370 nm and 880 nm were 56.6 ± 34.3 and 16.5 ± 11.2 Mm-1,respectively. σabspresented a double-peaks diurnal pattern with the maximum in the morning and the minimum in the afternoon. σabswas low in warm seasons and high in cold seasons. AAE ranged from 0.26 to 2.58 with the annual mean of 1.46, implying that both fossil fuel combustion and biomass burning influenced aerosol optical properties. σabsof BrC at 370 nm was 24.0 ± 5.7 Mm-1, contributing 42% to the total absorption. The highest AAE(1.52 ± 0.02) and largest BrC contributions(47% ± 4%) in winter suggested the significant influence of biomass burning on aerosol light absorption. Long-distance air masses passing through North China Plain and the Yangtze River Delta led to high AAE and BrC contributions. High AAE value of 1.46 in July indicated that long-range transport of the air pollutants from intense biomass burning in Southeast Asia would affect aerosol light absorption in Southeast China. The study will improve the understanding of light absorption properties of aerosols and the optical impacts of BrC in China. 展开更多
关键词 LIGHT ABSORPTION BROWN CARBON Black CARBON ABSORPTION ANGSTROM exponent Biomass burning Western Taiwan STRAIT
高频感应燃烧红外吸收法测定硅碳复合负极材料中的碳 预览
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作者 陈彩霞 李涛 付鹏飞 《化学分析计量》 CAS 2019年第2期65-67,共3页
采用高频感应燃烧红外吸收法测定硅碳复合负极材料中碳含量。分别考察了称样量,助熔剂种类、用量对测定结果的影响,确定了称样量为100~200mg,以1.5g钨粒、0.8g铁粒和0.3g锡粒为助熔剂。碳的线性相关系数为0.9999,检出限为0.84μg/g,测... 采用高频感应燃烧红外吸收法测定硅碳复合负极材料中碳含量。分别考察了称样量,助熔剂种类、用量对测定结果的影响,确定了称样量为100~200mg,以1.5g钨粒、0.8g铁粒和0.3g锡粒为助熔剂。碳的线性相关系数为0.9999,检出限为0.84μg/g,测定下限为2.8μg/g。测定结果的相对标准偏差为1.83%~2.02%(n=11),样品加标回收率为97.6%~101.1%。该方法快速、准确,适用于硅碳复合负极材料中碳含量的测定。 展开更多
关键词 高频感应燃烧红外吸收法 硅碳复合负极材料
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Thermal conductivity of natural rubber nanocomposites with hybrid fillers
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作者 Junping Song Xiteng Li +3 位作者 Kaiyan Tian Lianxiang Ma Wei Li Shichune Yao 《中国化学工程学报:英文版》 SCIE EI CAS CSCD 2019年第4期928-934,共7页
Natural rubber nanocomposites filled with hybrid fillers of multi-walled carbon nanotubes(CNTs) and carbon black(CB) were prepared. CNTs were ultrasonically modified in mixture of hydrogen peroxide(H2O2) and distilled... Natural rubber nanocomposites filled with hybrid fillers of multi-walled carbon nanotubes(CNTs) and carbon black(CB) were prepared. CNTs were ultrasonically modified in mixture of hydrogen peroxide(H2O2) and distilled water(H2O). The functional groups on the surface of CNTs, changes in nanotube structure and morphology were characterized by Fourier transform infrared spectroscopy(FT-IR), Raman Spectroscopy, and transmission electron microscopy(TEM). It shows that hydroxyl(OH·) is successfully introduced. The surface defects of modified CNTs were obviously higher than those of original CNTs, and the degree of agglomeration was greatly reduced. Thermal conductivity of the composites was tested by protection heat flow meter method. Compared with unmodified CNTs/CB filling system, the thermal conductivity of hybrid composites is improved by an average of 5.8% with 1.5 phr(phr is parts per hundred rubber) of hydroxyl CNTs and 40 phr of CB filled. A three-dimensional heat conduction network composed of hydroxyl CNTs and CB, as observed by TEM, contributes to the good properties. Thermal conductivity of the hybrid composites increases as temperature rises. The mechanical properties of hybrid composites are also good with hydroxyl CNTs filled nanocomposites;the tensile strength, 100% and 300% tensile stress are improved by 10.1%, 22.4% and 26.2% respectively. 展开更多
关键词 Modified CARBON NANOTUBE CARBON black HYBRID FILLER Natural rubber Thermal CONDUCTIVITY
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