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紫菜的营养价值研究概况 被引量:62
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作者 张全斌 赵婷婷 +2 位作者 綦慧敏 李智恩 徐祖洪 《海洋科学》 CAS CSCD 北大核心 2005年第2期69-72,共4页
关键词 紫菜 营养价值 营养成分 矿物质 碳水化合物 维生素 研究概况 含量 蛋白质
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锰离子非均匀掺杂TiO2薄膜电极光电催化测定COD 被引量:6
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作者 田玉华 李新军 +2 位作者 郑少健 张玉媛 冯满枝 《生态环境》 CSCD 北大核心 2008年第2期489-494,共6页
COD是水体质量评价的一个重要指标,目前对于COD测定方法主要是高锰酸钾法和重铬酸钾法,这些方法的测定工艺相对繁杂。本文采用溶胶-凝胶法分步控制工艺制备锰离子非均匀掺杂二氧化钛的薄膜电极,并用该薄膜作为光电催化电极测定COD。在... COD是水体质量评价的一个重要指标,目前对于COD测定方法主要是高锰酸钾法和重铬酸钾法,这些方法的测定工艺相对繁杂。本文采用溶胶-凝胶法分步控制工艺制备锰离子非均匀掺杂二氧化钛的薄膜电极,并用该薄膜作为光电催化电极测定COD。在三电极体系中,比较该薄膜电极与纯二氧化钛薄膜电极对于氧化丁二酸、乙醇、邻苯二甲酸氢钾、α-D-葡萄糖四种有机物的影响。实验结果表明:三电极体系中电子转移的电量与有机物完全矿化所需的化学需氧量(COD)有着内在的关系。在相同的条件下,锰离子非均匀掺杂二氧化钛的薄膜氧化降解丁二酸、乙醇、邻苯二甲酸氢钾、α-D-葡萄糖的速率大于纯二氧化钛薄膜。进一步结合线性扫描伏安(LSV)、阻抗谱等光电化学表征,从锰离子非均匀掺杂引起二氧化钛薄膜光生空穴-电子分离,初步分析了其光电催化活性提高的机理。 展开更多
关键词 COD 光电催化 TIO2薄膜 非均匀掺杂
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Synthesis,Structural Characterization and Magnetic Properties of{[Gd(DMF)_(3)(DMSO)(H_(2)O)_(3)](μ-CN)(Fe)(CN)_(5)]}·2H_(2)O
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作者 CHEN Wen-Tong CAI Li-Zhen +4 位作者 WU A-Qing GUO Guo-Cong HUANG Jin-Shun DONG Zhen-Chao Akiyuki Matsushita 《无机化学学报》 SCIE CAS CSCD 北大核心 2004年第6期693-697,共5页
A new cyano-bridged Gadolinium^(Ⅲ)-Iron^(Ⅲ)complex{[Gd(DMF)_(3)(DMSO)(H_(2)O)_(3)]2H_(2)0(DMF=N,N·-dimethylformamide;DMSO=dimethylsulfoxidel}was synthesized by the grinding reaction method,.It crysta-]llizes in... A new cyano-bridged Gadolinium^(Ⅲ)-Iron^(Ⅲ)complex{[Gd(DMF)_(3)(DMSO)(H_(2)O)_(3)]2H_(2)0(DMF=N,N·-dimethylformamide;DMSO=dimethylsulfoxidel}was synthesized by the grinding reaction method,.It crysta-]llizes in the triclinic.,space group P1 with ceIl parameters:a=O.90363(2)nm,b=1.25078(3)nm,c=1.41303(1)nm,穋m^(-3),Z=2,Mr=756.72,F(000)=760,Ⅲ)and the approxi-mately oriented octahedrally sixfold-coordinated Fe(Ⅲ)are linked by a cyano-bridge group to construct a dinuclear compound.The{[Gd(DMF)_(3)(DMSO)(H_(2)O)_(3)](Ⅲ)-Fe(Ⅲ)interaction is antiferromagnetic.CCDC:223430. 展开更多
关键词 crystal structure cyano-bridged dinuclear complex hybrid prussian blue complex molecular magnet lanthanide mixed ligand complex
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Biophysical Regulation of Carbon Flux in Different Rainfall Regime in a Northern Tibetan Alpine Meadow 被引量:5
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作者 CHAI Xi SHI Peili +3 位作者 ZONG Ning NIU Ben HE Yongtao ZHANG Xianzhou 《Journal of Resources and Ecology》 CSCD 2017年第1期30-41,共12页
Inter-annual variability in total precipitation can lead to significant changes in carbon flux.In this study,we used the eddy covariance(EC) technique to measure the net CO_2 ecosystem exchange(NEE) of an alpine m... Inter-annual variability in total precipitation can lead to significant changes in carbon flux.In this study,we used the eddy covariance(EC) technique to measure the net CO_2 ecosystem exchange(NEE) of an alpine meadow in the northern Tibetan Plateau.In 2005 the meadow had precipitation of 489.9 mm and in 2006 precipitation of 241.1 mm,which,respectively,represent normal and dry years as compared to the mean annual precipitation of 476 mm.The EC measured NEE was 87.70 g C m^(-2) yr^(-1) in 2006 and-2.35 g C m^(-2) yr^(-1) in 2005.Therefore,the grassland was carbon neutral to the atmosphere in the normal year,while it was a carbon source in the dry year,indicating this ecosystem will become a CO_2 source if climate warming results in more drought conditions.The drought conditions in the dry year limited gross ecosystem CO_2 exchange(GEE),leaf area index(LAI) and the duration of ecosystem carbon uptake.During the peak of growing season the maximum daily rate of NEE and Pmax and a were approximately 30%-50% of those of the normal year.GEE and NEE were strongly related to photosynthetically active radiation(PAR) on half-hourly scale,but this relationship was confounded by air temperature(Ta),soil water content(SWC) and vapor pressure deficit(VPD).The absolute values of NEE declined with higher Ta,higher VPD and lower SWC conditions.Beyond the appropriate range of PAR,high solar radiation exacerbated soil water conditions and thus reduced daytime NEE.Optimal T_a and VPD for maximum daytime NEE were 12.7℃ and 0.42 KPa respectively,and the absolute values of NEE increased with SWC.Variation in LAI explained around 77% of the change in GEE and NEE.Variations in R_e were mainly controlled by soil temperature(T_s),whereas soil water content regulated the responses of R_e to T_s. 展开更多
关键词 CO_2 flux different rainfall regime depression alpine meadow water stress Tibetan Plateau
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