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Characteristics of particle fluxes in the Prydz Bay polynya, Eastern Antarctica
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作者 Zhengbing HAN Chuanyu HU +4 位作者 Weiping SUN Jun ZHAO Jianming PAN Gaojing FAN Haisheng ZHANG 《中国科学:地球科学英文版》 SCIE EI CAS CSCD 2019年第4期657-670,共14页
The settling of particulate carbon in seawater is a key component of the ocean carbon cycle. We deployed a set of sediment trap in the polynya of Prydz Bay from December 2010 to December 2011 to investigate the season... The settling of particulate carbon in seawater is a key component of the ocean carbon cycle. We deployed a set of sediment trap in the polynya of Prydz Bay from December 2010 to December 2011 to investigate the seasonal variations in particle fluxes. There was a clear seasonal variation in the particle fluxes, with maximum and minimum fluxes recorded during the summer and winter, respectively. The average total flux over the sampling period was 193.58 mg m-2d-1, and the average fluxes of organic carbon(Corg), inorganic carbon(Cinorg), and biogenic silica(Sibio) were 721.78, 28.67, and 2382.80 μmol m-2 d-1, respectively. Sibiowas the main contributor to the total mass flux, and strongly correlated with Corg. The high Sibio/Corgmolar ratios(>1) suggest that Corgwas transported to deep sea in association with Sibio. By comparing remote sensing data of sea ice and chlorophyll in the upper water column, we found that the dynamics of carbon fluxes were closely related to changes in sea ice. Algae in sea ice may have a key role in biological pump processes in early summer. Apart from the ice algae bloom period, variations in carbon fluxes generally corresponded with phytoplankton blooms in the upper water. The ballast effect controlled the particle settling velocity and the efficiency of the biological pump. Sea ice rafts initiated the first particle export event and enhanced the particle settling efficiency during melting period. As diatoms might become less dominant in the ice-free area, sea ice loss may cause the efficiency of the biological pump efficiency to decrease over the long term. 展开更多
关键词 PRYDZ BAY Particle FLUXES Polynya BALLAST effect Biological PUMP efficiency
Diurnal and seasonal variations in carbon fluxes in bamboo forests during the growing season in Zhejiang province,China 预览
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作者 Liang Chen Yuli Liu +5 位作者 Guomo Zhou Fangjie Mao Huaqiang Du Xiaojun Xu Pingheng Li Xuejian Li 《林业研究:英文版》 CAS CSCD 2019年第2期657-668,共12页
Bamboo forest is an important forest type in subtropical China and is characterized by fast growth and high carbon sequestration capacity.However,the dynamics of carbon fluxes during the fast growing period of bamboo ... Bamboo forest is an important forest type in subtropical China and is characterized by fast growth and high carbon sequestration capacity.However,the dynamics of carbon fluxes during the fast growing period of bamboo shoots and their correlation with environment factors are poorly understood.We measured carbon dioxide exchange and climate variables using open-path eddy covariance methods during the 2011 growing season in a Moso bamboo forest(MB,Phyllostchys edulis)and a Lei bamboo forest(LB,Phyllostachys violascens)in Zhejiang province,China.The bamboo forests were carbon sinks during the growing season.The minimum diurnal net ecosystem exchange(NEE)at MB and LB sites were-0.64 and-0.66 mg C m^-2 s^-1,respectively.The minimum monthly NEE,ecosystem respiration(RE),and gross ecosystem exchange(GEE)were-99.3±4.03,76.2±2.46,and-191.5±4.98 g C m-2 month-1,respectively,at MB site,compared with-31.8±3.44,70.4±1.41,and-157.9±4.86 g C m^-2 month^-1,respectively,at LB site.Maximum RE was 92.1±1.32 g C m^-2 month^-1 at MB site and 151.0±2.38 g C m^-2 month^-1 at LB site.Key control factors varied by month during the growing season,but across the whole growing season,NEE and GEE at both sites showed similar trends in sensitivities to photosynthetic active radiation and vapor pressure deficit,and air temperature had the strongest correlation with RE at both sites.Carbon fluxes at LB site were more sensitive to soil water content compared to those at MB site.Both onyear(years when many new shoots are produced)and offyear(years when none or few new shoots are produced)should be studied in bamboo forests to better understand their role in global carbon cycling. 展开更多
关键词 Bamboo forest EDDY COVARIANCE CARBON fluxes CARBON SEQUESTRATION
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Effect of CeO2 on heat transfer and crystallization behavior of rare earth alloy steel mold fluxes 预览
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作者 Ze-yun Cai Bo Song +2 位作者 Long-fei Li Zhen Liu Xiao-kang Cui 《矿物冶金与材料学报:英文版》 SCIE EI CAS CSCD 2019年第5期565-572,共8页
To improve the heat transfer capability and the crystallization property of the traditional mold flux,CaF2 was replaced with B2O3.Then,the influences of CeO2 on the heat transfer and the crystallization of the CaF2-be... To improve the heat transfer capability and the crystallization property of the traditional mold flux,CaF2 was replaced with B2O3.Then,the influences of CeO2 on the heat transfer and the crystallization of the CaF2-bearing mold flux and the new mold flux with 10wt% B2O3 were studied using a slag film heat flux simulator and X-ray diffraction (XRD).The results revealed that the addition of CeO2 reduced the heat transfer by increasing the solid slag thickness and the crystallization of two mold fluxes.However,CeO2 had less effect on the B2O3-containing mold flux compared with the CaF2-bearing mold flux.According to the analyses,the CeO2 contents in the CaF2-bearing mold flux and the B2O3-containing mold flux should not exceed 8wt% and 12wt%,respectively.Therefore,these experimental results are beneficial to improve and develop the mold flux for casting rare earth alloy steels. 展开更多
关键词 CERIUM oxide BORON TRIOXIDE MOLD FLUXES heat transfer crystallization rare earth alloy steels
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Characterizing nitric oxide emissions from two typical alpine ecosystems
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作者 Fei Lin Chunyan Liu +5 位作者 Xiaoxia Hu Yongfeng Fu Xunhua Zheng Rui Wang Wei Zhang Guangmin Cao 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第3期312-322,共11页
portion of alpine meadows has been and will continue to be cultivated due to the concurrent increasing demands for animal-and crop-oriented foods and global warming.However, it remains unclear how these long-term chan... portion of alpine meadows has been and will continue to be cultivated due to the concurrent increasing demands for animal-and crop-oriented foods and global warming.However, it remains unclear how these long-term changes in land use will affect nitric oxide(NO) emission. At a field site with a calcareous soil on the Qinghai-Tibetan Plateau,the authors measured the year-round NO fluxes and related variables in a typically wintergrazed natural alpine meadow(NAM) and its adjacent forage oat field(FOF). The results showed that long-term plow tillage, fertilization and growing forage oats significantly yielded ca. 2.7 times more(p < 0.01) NO emissions from the FOF than the NAM(conservatively 208 vs. 56 g N/(ha·year) on average). The spring freeze–thaw period and non-growing season accounted for 17%-35% of the annual emissions, respectively. The Q10 of surface soil temperature(Ts) was 8.9 in the NAM(vs. 3.8 in the FOF), indicating increases of 24%–93% in NO emissions per 1–3 °C increase. However, the warming-induced increases could be smaller than those due to land use change and management practices. The Tsand concentrations of ammonium, nitrate and water-extractable organic carbon jointly explained 69% of the variance in daily NO fluxes from both fields during the annual period(p < 0.001). This result indicates that temporally and/or spatially distributed NO fluxes from landscapes with calcareous soils across native alpine meadows and/or fields cultivated with forage oats can be predicted by simultaneous observations of these four soil variables. 展开更多
关键词 ALPINE MEADOW Annual NO FLUXES Non-growing SEASON Freeze–thaw period Land use change Global WARMING
The analysis of heat and water fluxes in frozen silty soil 预览
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作者 DaHu Rui Ming Lu +1 位作者 Kunio Watanabe Jun Zhang 《寒旱区科学:英文版》 CSCD 2019年第1期21-28,共8页
In this paper,based on the basic equations of water flow and heat transfer,the hydrothermal coupling model is established.The numerical model was realized in COMSOL Multiphysics software,and simulation results are com... In this paper,based on the basic equations of water flow and heat transfer,the hydrothermal coupling model is established.The numerical model was realized in COMSOL Multiphysics software,and simulation results are compared with the experimental results of Watanabe and Wake(2008)to verify the effectiveness of the model.Through the calculation,we can obtain the dynamic changes of heat and water fluxes,thermal and hydrological properties,matric potential and temperature gradient in unsaturated freezing soil;and these variables are unmeasurable in practice. 展开更多
关键词 UNSATURATED FREEZING soil HYDROTHERMAL coupling HEAT and water FLUXES COMSOL
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Flux blended synthesis of novel Y2O3:Eu^3+ sensing arrays for highly sensitive dual mode detection of LFPs on versatile surfaces
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作者 K.N. Venkatachalaiah H. Nagabhushana +3 位作者 R.B. Basavaj G.R Darshan B. Daruka Prasad S.C. Sharma 《中国稀土学报:英文版》 SCIE EI CAS CSCD 2018年第9期954-964,共11页
关键词 Y2O3 混合 流动 双模式 合成 表面 万用 敏感
河流入海通量在线监测方法及标准化工作探讨
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作者 侯二虎 武贺 +1 位作者 周庆伟 白杨 《标准科学》 2018年第10期80-84,共5页
我国现有的人海通量研究多基于历史监测资料,采用短期或长期等不同估算方法,无法准确反映河流入海污染物现状,通量监测标准化工作尚处于起步阶段。本文研究了通量监测的现状及存在的问题,提出了适用于在线形式的监测方法,比较了各... 我国现有的人海通量研究多基于历史监测资料,采用短期或长期等不同估算方法,无法准确反映河流入海污染物现状,通量监测标准化工作尚处于起步阶段。本文研究了通量监测的现状及存在的问题,提出了适用于在线形式的监测方法,比较了各方法的实现方式、特点及适用范围,实现了流量与水质监测的有机结合,提出了推进入海通量在线监测标准化工作的建议。 展开更多
关键词 通量 在线 监测 标准化
Estimating submarine groundwater discharge and associated nutrient inputs into Daya Bay during spring using radium isotopes 预览
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作者 Jing-yan Gao Xue-jing Wang +1 位作者 Yan Zhang Hai-long Li 《水科学与水工程:英文版》 EI CAS CSCD 2018年第2期120-130,共11页
Daya Bay,a semi-enclosed bay in the South China Sea,is well known for its aquaculture,agriculture,and tourism.In recent years,many environmental problems have emerged,such as the frequent(almost yearly)occurrence of h... Daya Bay,a semi-enclosed bay in the South China Sea,is well known for its aquaculture,agriculture,and tourism.In recent years,many environmental problems have emerged,such as the frequent(almost yearly)occurrence of harmful algal blooms and red tides.Therefore,investigations of submarine groundwater discharge(SGD)and associated nutrient inputs to this bay have important theoretical and practical significance to the protection of the ecological system.Such a study was conducted using short-lived radium isotopes 223Ra and 224Ra.The estimated SGD fluxes were 2.89×10^7 m^3/d and 3.05×10^7 m^3/d based on 223Ra and 224Ra,respectively.The average SGD flux was about 35 times greater than that of all the local rivers.The SGD-associated dissolved inorganic nitrogen(DIN)and dissolved inorganic phosphorus(DIP)fluxes ranged from 1.95×10^6 to 2.06×10^6 mol/d and from 5.72×10^4 to 6.04×10^4 mol/d,respectively.The average ratio of DIN to DIP fluxes in SGD was 34,much higher than that in local rivers(about 6.46),and about twice as large as the Redfield ratio(16).Our results indicate that SGD is a significant source of nutrients to the bay and may cause frequent occurrence of harmful algal blooms.This study provides baseline data for evaluating potential environmental effects due to urbanization and economic growth in this region. 展开更多
关键词 SUBMARINE groundwater discharge(SGD) RADIUM isotopes RADIUM mass balance model SGD-associated NUTRIENT fluxes DAYA Bay
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Evaluation of the CAM and PX Surface Layer Parameterization Schemes for Momentum and Sensible Heat Fluxes Using Observations
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作者 Youshan JIANG Dongqing LIU Gang LIU 《气象学报:英文版》 SCIE CSCD 2018年第6期1026-1040,共15页
In this study, the performances of the Community Atmosphere Model (CAM) and Pleim-Xiu (PX) surface layer parameterization schemes are investigated by using field observations. The parameterization schemes are evaluate... In this study, the performances of the Community Atmosphere Model (CAM) and Pleim-Xiu (PX) surface layer parameterization schemes are investigated by using field observations. The parameterization schemes are evaluated against continuous momentum and sensible heat flux observations measured at two flat and homogeneous grassland sites in the suburb of Nanjing, eastern China. The observations were conducted from 30 December 2014 to 18 April 2017 at Jiangxinzhou and from 9 February 2015 to 26 March 2018 at Jiangning. It is found that the momentum flux is overall in good agreement with the observation, and the sensible heat flux is overestimated. The parameterizations of the momentum and sensible heat fluxes well capture the diurnal and seasonal patterns seen in the observations at the two sites. At Jiangxinzhou, the PX parameterization underestimates the momentum flux throughout the day and the CAM parameterization slightly overestimates it around the noon, while they underestimate the momentum flux throughout the year. The two parameterizations overestimate the sensible heat flux in the daytime as well as over the entire year. At Jiangning, the two parameterizations overestimate the momentum flux throughout the day and the sensible heat flux in the daytime, and overestimate both of them over the entire year. The two parameterizations are not significantly different from each other in reproducing the turbulent fluxes at the same site, while they perform differently at the two sites in terms of statistics. In addition, the parameterized fluxes increase with increased roughness length. 展开更多
关键词 EVALUATION PARAMETERIZATION TURBULENT FLUXES surface layer
Mechanism to remove oxide inclusions frommolten aluminum bymethodsolid fluxes refining
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作者 Cong Li Jian-guo Li +1 位作者 Yi-zhe Mao Jia-cheng Ji 《中国铸造:英文版》 SCIE 2017年第4期233-243,共11页
A novel flux charging method and a crucible quenching method were employed to study themechanism of solid fluxes refining method regarding the removal of oxide inclusions (Al203) from molten aluminum.Electrochemical... A novel flux charging method and a crucible quenching method were employed to study themechanism of solid fluxes refining method regarding the removal of oxide inclusions (Al203) from molten aluminum.Electrochemical polishing method was adopted to prepare surfaces of the samples. Through experiments, themorphology of the residual solidified flux in the solidified samples as well as the wetting action of the molten fluxduring refining were observed for the first time. Three wetting regimes denoted by absorbing regime, engulfingregime and penetration regime correlating with the removal of oxide films (the most typical and common oxideinclusions in molten aluminum) were proposed in terms of different types and distributions of oxide films anddifferent size ratios of the molten flux to oxide films. Particularly, from a thermodynamic point of view, for the firsttime, the penetration regime provided concrete evidence that the practical oxide inclusions can be wet by moltenflux under ambient fluid of molten aluminum. A spreading model was proposed, according to which ingredients andsize parameters of practical solid fluxes can be optimized. 展开更多
关键词 MELT quality INCLUSIONS removal MELT treatment FLUXES aluminum CASTING
烧结中使用钢渣磁选尾渣替代部分烧结熔剂的实验研究 预览 被引量:1
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作者 孟飞 刘清才 +5 位作者 朱广太 任山 朱博洪 兰苑培 刘国庆 牛德良 《中南大学学报:自然科学版》 EI CAS CSCD 北大核心 2017年第1期31-38,共8页
通过化学分析、X线衍射分析、光学显微分析等方法对钢渣磁选后剩余尾渣进行基础特性分析,并将其按照质量分数0,2.5%,5.0%和10.0%的比例分别配入烧结原料中,研究其代替部分烧结熔剂对烧结矿显微结构、质量及冶金性能的影响。研究结果表... 通过化学分析、X线衍射分析、光学显微分析等方法对钢渣磁选后剩余尾渣进行基础特性分析,并将其按照质量分数0,2.5%,5.0%和10.0%的比例分别配入烧结原料中,研究其代替部分烧结熔剂对烧结矿显微结构、质量及冶金性能的影响。研究结果表明:当烧结原料中尾渣配入量小于5.0%时,随着尾渣配入量的增加,烧结矿中铁酸钙含量增加,烧结矿的成品率、落下强度及转鼓强度均逐渐增大,之后均开始降低,而垂直烧结速度及烧结利用系数则一直逐渐降低。烧结矿的还原度及低温还原粉化性能随着尾渣配入量得到改善,但当尾渣配入量大于5.0%时开始下降。尾渣的配入会提高烧结矿的自由流动及完全熔化温度,扩大软熔区间,使得烧结矿软熔性能变差。 展开更多
关键词 磁选尾渣 烧结 熔剂 冶金性能
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潮水作用下苏北海岸带盐沼甲烷通量时空特征研究
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作者 颜文 王进欣 +1 位作者 赵赟昊 郭楠 《海洋湖沼通报》 CSCD 北大核心 2017年第3期7-14,共8页
甲烷是大气中重要的温室气体,对全球气候变暖具有重要的贡献,在全球的碳循环中也扮演着重要的角色。2013年7月(生长季)和2013年12月(非生长季)在中国江苏省盐城海岸带盐沼湿地采用静态箱技术原位测定CH4的通量。结果表明,在光滩和... 甲烷是大气中重要的温室气体,对全球气候变暖具有重要的贡献,在全球的碳循环中也扮演着重要的角色。2013年7月(生长季)和2013年12月(非生长季)在中国江苏省盐城海岸带盐沼湿地采用静态箱技术原位测定CH4的通量。结果表明,在光滩和植被演替带上,光滩、互花米草带和獐茅带甲烷的通量均值分别为0.26±0.44mg·m^-2·d^-1、25.83±4.25mg·m^-2·d^-1和2.68±1.47mg·m^-2·d^-1表现为甲烷的源,盐地碱蓬带通量均值为-0.56±0.94mg·m^-2·d^-1表现为甲烷的汇,距离潮沟远近上,潮沟处甲烷的通量均值最大(16.90±3.71mg·m^-2·d^-1),大于近潮沟处(5.17±2.11mg·m^-2·d^-1)和远潮沟处的甲烷通量均值(8.93±3.21mg·m^-2·d^-1);植被区生长季与非生长季甲烷通量较为接近,甲烷通量均值分别为10.48±2.90mg·m^-2·d^-1、9.65±2.29mg·m^-2·d^-1,生长季的甲烷通量略大于非生长季的甲烷通量;生长季潮水周期性变化中落潮甲烷通量比涨潮、平潮时期的甲烷通量值大,非生长季涨潮时期甲烷通量大于平潮、落潮时期的甲烷通量。高等植物的地上部分去除对甲烷的排放影响不一,去除高等植物后的互花米草带甲烷通量增加,盐地碱蓬带和獐茅带甲烷通量减少。盐沼甲烷排放与丰富的有机质有关,有机质提供甲烷产生的基质。在过碱的盐沼环境中产甲烷菌的活性受到限制,甲烷的通量与pH的呈负相关。硫酸盐浓度在378mg/L-530mg/L与甲烷通量无相关性、530mg/L-1100mg/L与甲烷通量呈正相关,在1100mg/L-1130mg/L与甲烷通量呈负相关。生长季光照、温度与甲烷通量呈正相关。 展开更多
关键词 盐沼 甲烷 潮水 通量
沙颖河丰水期CH4排放特征及其影响因子研究 被引量:1
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作者 马培 李亚林 +2 位作者 戚蓝月 田宪峰 杨丽标 《环境科学与技术》 CAS CSCD 北大核心 2017年第2期26-30,38共6页
为研究沙颍河表层水体CH4溶存浓度、饱和度、释放特征,该研究于7-9月利用顶空模型法对沙颍河主要站点进行观测分析,并探讨了环境因子对水体CH4的影响。结果表明:丰水期沙颍河各个采样点CH4浓度在0.001 2-3.120 4μmol/L之间,与世界河... 为研究沙颍河表层水体CH4溶存浓度、饱和度、释放特征,该研究于7-9月利用顶空模型法对沙颍河主要站点进行观测分析,并探讨了环境因子对水体CH4的影响。结果表明:丰水期沙颍河各个采样点CH4浓度在0.001 2-3.120 4μmol/L之间,与世界河流相比处于较高的浓度水平。贾鲁河上游水体CH4浓度最高,沙河-颍河交汇处浓度最低。水气界面CH4的释放强度为(2.295 4±2.073 9)μmol/(m-2·h)。昼夜分析显示,沙颍河丰水期CH4昼夜均处于过饱和状态,是大气的源。贾鲁河上游CH4昼间释放量占总排放量的一半,沙颍河干流昼间排放量占61.06%,显著大于夜间排放量。丰水期水温偏高、DO偏低以及高浓度的NH3-N是造成沙颍河CH4浓度偏高的主要原因。 展开更多
关键词 沙颍河 CH4 排放通量 影响因子
亚热带典型岩溶溪流水气界面CO_2交换通量变化过程及其环境影响 被引量:6
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作者 李丽 蒲俊兵 +3 位作者 李建鸿 于奭 肖琼 张陶 《环境科学》 CAS CSCD 北大核心 2016年第7期2487-2495,共9页
具有较高水体CO_2分压(p CO_2)的岩溶地下水出露地表后常与大气形成较高的正向CO_2浓度梯度,因此评价岩溶水体水气界面CO_2交换通量对于岩溶碳循环过程研究具有重要意义.本文以广西柳州官村地下河补给的地表溪流为研究对象,详细讨论... 具有较高水体CO_2分压(p CO_2)的岩溶地下水出露地表后常与大气形成较高的正向CO_2浓度梯度,因此评价岩溶水体水气界面CO_2交换通量对于岩溶碳循环过程研究具有重要意义.本文以广西柳州官村地下河补给的地表溪流为研究对象,详细讨论了岩溶溪流水-气界面CO_2交换通量.使用静态箱法和手持式二氧化碳测量仪GM70对脱气通量进行检测,结果表明,溪流的CO_2交换通量以脱气为主,地下河出口(G1点)脱气通量变化范围为139.48~890.84 mg·(m^2·h)^-1,平均值为445.72mg·(m^2·h)^-1,溪流下游(G2点)脱气通量变化范围为16.54~844.18 mg·(m^2·h)^-1,平均值为159.81 mg·(m^2·h)^-1,脱气通量的时空变化特征表现为雨季要大于旱季,地下河出口地区要大于下游地区.溪流CO_2脱气会对附近空气中CO_2气体碳同位素(δ~(13)C-CO_2)产生影响,使溪流附近空气中CO_2气体碳同位素(δ~(13)C-CO_2)值逐渐偏负,并表现出明显的时空变化,即δ13C-CO_2雨季偏负于旱季,G1点δ~(13)C-CO_2偏负于G2点.并且由于脱气作用的进行,溪流的水化学性质沿流程变化,表现为HCO-3沿流程逐渐降低,p H值升高,电导率降低,p CO_2沿流程递减,常见碳酸盐矿物的饱和指数SIc逐渐升高,δ~(13)C-DIC值逐渐偏正. 展开更多
关键词 岩溶地表溪流 CO2脱气 通量 影响因素 官村岩溶地表溪流
环渤海河流COD入海通量及其对渤海海域COD总量的贡献 预览 被引量:3
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作者 晋春虹 李兆冉 盛彦清 《中国环境科学》 EI CAS CSCD 北大核心 2016年第6期1835-1842,共8页
于2013年8月~2014年10月,分季节对环渤海36条入海河流进行了4次调查采样,核算其COD入海通量,并评估其对渤海水质的影响.结果表明,大部分河流都受到了严重污染(COD为地表IV类),但污染最重的河流并不是COD入海通量最大的河流,COD的最大... 于2013年8月~2014年10月,分季节对环渤海36条入海河流进行了4次调查采样,核算其COD入海通量,并评估其对渤海水质的影响.结果表明,大部分河流都受到了严重污染(COD为地表IV类),但污染最重的河流并不是COD入海通量最大的河流,COD的最大值和COD入海通量的最大值不具有一致性;环渤海河流排入渤海的CODCr的年入海通量最大(606万t),其次是酸性COD_(Mn)的入海通量(62万t),碱性COD_(Mn)最小,为53万t;环渤海河流在丰水期COD的入海通量约占全年的68%,其次是平水期(28%),枯水期最小(4%);整个渤海海域的碱性COD_(Mn)总量为239万t,其中环渤海河流输入约占25%. 展开更多
关键词 渤海 沿海河流 COD 入海通量
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红色荧光粉Ca3Y2Si3O12:Eu^3+的制备及发光特性
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作者 吴疆 张萍 +1 位作者 蒋春东 邱泽忠 《稀有金属材料与工程》 SCIE EI CAS CSCD 北大核心 2016年第4期1030-1034,共5页
采用高温固相法合成了红色荧光粉Ca3Y2Si3O12:Eu^3+。研究了Eu^3+离子掺杂浓度、助熔剂及Gd^3+共掺杂对荧光粉发光特性的影响。XRD检测结果显示,荧光粉的主晶相为Ca3Y2Si3O12,属单斜晶系。荧光光谱分析表明:硅酸盐荧光粉Ca3Y2Si3O1... 采用高温固相法合成了红色荧光粉Ca3Y2Si3O12:Eu^3+。研究了Eu^3+离子掺杂浓度、助熔剂及Gd^3+共掺杂对荧光粉发光特性的影响。XRD检测结果显示,荧光粉的主晶相为Ca3Y2Si3O12,属单斜晶系。荧光光谱分析表明:硅酸盐荧光粉Ca3Y2Si3O12:Eu^3+的发射光谱包含2个主峰,峰值分别位于590和614 nm,归属于Eu^3+离子从-5D0→7-F1和-7F2的特征跃迁。用614 nm最强峰监测,得到激发光谱为一多峰宽带(200-500 nm)。改变Eu^3+离子掺杂浓度发现:随着掺杂量增加,荧光粉发光强度先增加后降低,最佳掺杂量为20 mol%;讨论了几种助熔剂的影响:NaCl、CaF2作为助熔剂,对荧光粉的发光强度影响不大,H3BO3作为助熔剂降低荧光粉的发光强度,而NH4F能显著提高荧光粉的发光强度;Gd^3+可以作为一种很好的共激活剂,敏化Eu^3+离子发光。 展开更多
关键词 红色荧光粉 Eu3+离子掺杂 高温固相法 助熔剂 Gd3+离子掺杂
中国东部海域底质沉积物中重金属研究现状 预览 被引量:4
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作者 陈彬 刘健 +2 位作者 范德江 刘明 郭志刚 《海洋地质与第四纪地质》 CAS CSCD 北大核心 2016年第1期43-56,共14页
中国东部海域(渤海、黄海和东海)底质沉积物接受了巨量的重金属(As、Cd、Cu、Cr、Hg、Ni、Pb、Zn和V),从而使得底质环境质量可能面临严重的重金属污染。这些重金属来源复杂,其中既有自然源重金属又有不同人为来源。其中自然源可能... 中国东部海域(渤海、黄海和东海)底质沉积物接受了巨量的重金属(As、Cd、Cu、Cr、Hg、Ni、Pb、Zn和V),从而使得底质环境质量可能面临严重的重金属污染。这些重金属来源复杂,其中既有自然源重金属又有不同人为来源。其中自然源可能主要包括长江流域、黄河流域的泥沙和中国西部沙漠的粉尘,人为来源可能主要包括煤炭和燃油消耗、钢铁冶炼和有色金属冶炼,其中煤炭消耗和有色金属冶炼可能是中国东部海域沉积物铅和汞的最主要的来源。这些重金属主要通过河流输入的方式进入到中国东部海域,尽管鉴定沉积物中重金属具体人为来源的方法较多,但在中国东部海域应用最为成功的是铅稳定同位素。尽管巨量的重金属输入到中国东部海域,但绝大部分海域底质沉积物质量良好,仅在锦州湾海域重金属含量严重超标。 展开更多
关键词 重金属 来源 通量 环境质量 中国东部海域
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助熔剂对Gd1-xTbxNbO4绿色荧光粉的形貌及发光性能的影响
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作者 周伟杰 王广发 +3 位作者 高林辉 巩子强 廖世才 祝洪良 《浙江理工大学学报》 2016年第6期808-813,共6页
采用传统的高温固相法制备出了不同掺杂浓度的Gd_(1-x)Tb_xNbO_4绿色荧光粉。荧光光谱分析表明,Gd_(1-x)Tb_xNbO_4荧光粉的最强发射峰归属于Tb^(3+)离子^5D_4→^7F_5电子跃迁(543nm)的强绿光发射且当Tb^(3+)掺杂浓度为20%... 采用传统的高温固相法制备出了不同掺杂浓度的Gd_(1-x)Tb_xNbO_4绿色荧光粉。荧光光谱分析表明,Gd_(1-x)Tb_xNbO_4荧光粉的最强发射峰归属于Tb^(3+)离子^5D_4→^7F_5电子跃迁(543nm)的强绿光发射且当Tb^(3+)掺杂浓度为20%时荧光粉的发光强度达到最大值,即绿色荧光粉Gd_(1-x)Tb_xNbO_4的最佳掺杂浓度为20%。在最佳掺杂浓度的基础上,于制备过程中添加助熔剂可以进一步提高Gd_(1-x)Tb_xNbO_4荧光粉的发光性能,尤其是以Na_2SO_4为助熔剂不仅可以得到分散性好、颗粒尺寸分布范围窄的微米尺寸鹅卵石状颗粒,且位于543nm处的绿光发射强度相比无任何助熔剂辅助时所得产物的发光强度提高了约1.3倍。 展开更多
关键词 Gd1-xTbxNbO4 绿色荧光粉 发光性能 助熔剂
全文增补中
不同助熔剂对磷矿熔融特性影响研究 被引量:2
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作者 汤建伟 兰方杰 +3 位作者 化全县 刘咏 刘丽 王保明 《化工矿物与加工》 CAS 北大核心 2016年第9期9-12,19共5页
利用分析纯级Ca3(PO4)2、SiO2、Al2O3、MgO为原料模拟磷矿组成,研究SiO2、Al2O3、MgO对磷矿熔点的影响。结果表明,SiO2、Al2O3、MgO单独添加均可改善物料的熔融特性,且SiO2对降低物料熔点的促进效果优于其他两种助熔剂;SiO2/CaO摩尔比... 利用分析纯级Ca3(PO4)2、SiO2、Al2O3、MgO为原料模拟磷矿组成,研究SiO2、Al2O3、MgO对磷矿熔点的影响。结果表明,SiO2、Al2O3、MgO单独添加均可改善物料的熔融特性,且SiO2对降低物料熔点的促进效果优于其他两种助熔剂;SiO2/CaO摩尔比为0.85~1.75、MgO/CaO摩尔比为0.75~1.5时SiO2-MgO复合助熔体系磷矿存在低熔点区,熔融温度介于1260~1290℃之间;SiO2/CaO摩尔比为0.3~1.25、Al2O3/CaO摩尔比为0.25~1.0,和SiO2/CaO摩尔比为1.4~1.75、Al2O3/CaO摩尔比为0.3~1.25两种条件下SiO2-Al2O3复合助熔体系磷矿均存在低熔点区,熔融温度介于1400~1420℃之间。研究结果为深入研究磷矿熔融还原反应提供了理论依据。 展开更多
关键词 磷矿 助熔剂 熔点 相图
The Modeled Atmospheric and Oceanic Response to the South China Sea SST Anomaly 预览
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作者 ZHU Xiande WU Lixin +1 位作者 ZHOU Jun GAO Jianjun 《中国海洋大学学报:英文版》 SCIE CAS 2016年第5期741-750,共10页
The sensitivity of the global atmospheric and oceanic response to sea surface temperature anomaly(SSTA) throughou the South China Sea(SCS) is investigated using the Fast Ocean-Atmosphere Model(FOAM). Forced by a warmi... The sensitivity of the global atmospheric and oceanic response to sea surface temperature anomaly(SSTA) throughou the South China Sea(SCS) is investigated using the Fast Ocean-Atmosphere Model(FOAM). Forced by a warming SST, the ex periment explicitly demonstrates that the responses of surface air temperature(SAT) and SST exhibit positive anomalous center ove SCS and negative anomalous center over the Northern Pacific Ocean(NPO). The atmospheric response to the warm SST anomalie is characterized by a barotropical anomaly in middle-latitude, leading to a weak subtropical high in summer and a weak Aleutian low in winter. Accordingly, Indian monsoon and eastern Asian monsoon strengthen in summer but weaken in winter as a result of wind convergence owing to the warm SST. It is worth noting that the abnormal signals propagate poleward and eastward away in the form of Rossby Waves from the forcing region, which induces high pressure anomaly. Owing to action of the wind-driven circulation, an anomalous anti-cyclonic circulation is induced with a primary southward current in the upper ocean. An obvious cooling appear over the North Pacific, which can be explained by anomalous meridional cold advection and mixing as shown in the analysises o heat budget and other factors that affect SST. 展开更多
关键词 South China Sea SSTA thermodynamic budgets wave activity fluxes
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