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Sorption of Eu^(3+) onto nano-size silica-water interfaces

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Science China earth sciences 2005年第11期48卷 1942-1948页

作者： HU Ping1,2, YIN Xiulan3 , ZHAO Linghu1 & LI Dien4 1. Department of earth sciences, China University of Geosciences, Wuhan 430074, China 2. Northeastern Illinois University, Chicago, IL 60625, usa 3. China Institute of Geo-environmental Monitoring, Beijing 100081, China 4. division of Chemistry, los alamos national laboratory, los alamos, nm 87544, usa Department of earth sciences China University of Geosciences Wuhan China Northeastern Illinois University Chicago IL USA China Institute of Geo-environmental Monitoring Beijing China division of Chemistry Los Alamos National Laboratory Los Alamos NM USA

The sorption of Eu species onto nano-size silica-water interfaces is investigated at pH range of 1―8.5 and the initial Eu concentrations (CEu) of 2 × 10?5, 2 × 10?4 and 2 × 10?3 M using fluorescence spectroscopy. The sorption rate of Eu is initially low, but significantly in-creases at pH > 4. For the initial CEu of 2 × 10?5, 2 × 10?4 and 2 × 10?3 M, the dissolved Eu spe-cies are completely sorbed onto silica-water interfaces at pH = 4.75, ~5.8 and 6.6, respectively, with the respective sorption densities of ~1.58 × 10?8, 1.58 × 10?7 and 1.58 × 10?6 mol/m2. The sorbed Eu species at pH < 6 is aquo Eu3+, which is sorbed onto silica-water interfaces as an outer-sphere complex at pH < 5, but may be sorbed as an inner-sphere bidentate complex at 5 < pH < 6, due to the decrease of the NH2O to ~6 at pH = 6. At pH = 6 – 8, Eu(OH)2+, Eu(CO3)+ and Eu(CO3)2? form in the solutions, and Eu(CO3)+ is dominant at pH = ~7.5. These ions may be sorbed onto silica-water interfaces as inner-sphere bidentate complexes or multi-nuclear pre-cipitates.

关键词： surface sorption, Eu3+ species, nano-size silica, fluorescence spectroscopy, immobilization of toxic metals

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Magnetic characterization of noninteracting,randomly oriented,nanometer-scale ferrimagnetic particles

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Magnetic characterization of noninteracting,randomly oriente...

Photosynthetically active radiation retrieval based on HJ-1A/B satellite data

中国科学院地质与地球物理研究所第十届(2010年度)学术年会

作者： Changqian Cao,Lanxiang Tian,Qingsong Liu,Weifeng Liu,Guanjun Chen, and Yongxin Pan 1 Paleomagnetism and Geochronology laboratory,Key laboratory of the earth’s Deep Interior,Institute of Geology and Geophysics,Chinese Academy of sciences,Beijing,China. 2 Also at France-China Bio-Mineralization and Nano-Structures laboratory,Institute of Geology and Geophysics,Chinese Academy of sciences,Beijing,China. 3 Also at Graduate University of Chinese Academy of sciences,Beijing, China. 4 State Key laboratory of Microbial Technology,School of Life sciences,Shandong University,Jinan,China.

[1]Studying the magnetic properties of ultrafine nanometer-scale femmagnetic particles (<10 nm)is vital to our understanding of superparamagnetism and its applications to environmental magnetism,biogeomagnetism,iron b...

[1]Studying the magnetic properties of ultrafine nanometer-scale femmagnetic particles (nm)is vital to our understanding of superparamagnetism and its applications to environmental magnetism,biogeomagnetism,iron biomineralization,and biomedical ***,magnetic properties of the ultrafine nanometer-sized femmagnetic grains are very poorly constrained because of ambiguities caused by particle magnetostatic interactions and unknown size *** resolve these problems,we synthesized magnetoferritins using the recombinant human H chain ferritin(HFn). These femmagnetic HFn were further purified through size exclusion chromatography to obtain monodispersed ferrimagnetic *** electron microscopy revealed that the purified ferrimagnetic HFn are monodispersed and each consists of an iron oxide core(magnetite or maghemite)with an average core diameter of 3.9±1.1 nm imbedded in an intact protein *** R value of the Wohlfarth-Cisowski test measured at 5 K is 0.5,indicating no magnetostatic *** saturation isothermal remanent magnetization acquired at 5 K decreased rapidly with increasing temperature with a median unblocking temperature of 8.2 *** preexponential frequency factor f determined by AC susceptibility is(9.2±7.9)×*** extrapolated M/M and B/B at 0 K are 0.5 and 1.12,respectively,suggesting that the ferrimagnetic HFn cores are dominated by uniaxial *** calculated effective magnetic anisotropy energy constant K=1.2×10 J/m,which is larger than previously reported values for bulk magnetite and/or maghemite or magnetoferritin and is attributed to the effect of surface *** data provide useful insights into superparamagnetism as well as biomineralization of ultrafine ferrimagnetic particles.

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Science China earth sciences 2010年第S1期53卷 81-91页

作者： LI Li1,XIN XiaoZhou1,SU GaoLi1,2 & LIU QinHuo1 1 State Key laboratory of Remote Sensing Science,Institute of Remote Sensing Applications,Chinese Academy of sciences,Beijing 100101,China 2 Zhejiang Climate Center,Hangzhou 310017,China State Key laboratory of Remote Sensing Science Institute of Remote Sensing Applications Chinese Academy of Sciences Beijing China Zhejiang Climate Center Hangzhou China

Photosynthetically active radiation(PAR) is essential for plant photosynthesis and carbon cycle,and is also important for meteorological and environmental *** advance China's disaster and environmental monitoring capabilities,the HJ-1A/B satellites have been placed in earth *** of their environmental monitoring objectives is the study of *** simulated direct solar,scattered and environment radiation between 400 and 700 nm under different atmospheric parameters(solar zenith angle,atmospheric water vapor,atmospheric ozone,aerosol optical thickness,surface elevation and surface albedo),and then established a look-up table between these input parameters and *** on the look-up table,we used HJ-1A/B aerosol and surface albedo outputs to derive the corresponding *** of inversed instantaneous and observed PAR values using HJ-1 Heihe experimental data had a root mean square error of 25.2 W m-2,with a relative error of 5.9%.The root mean square error for accumulated daily PAR and observed values was 0.49 MJ m-2,with a relative error of 3.5%.Our approach improved significantly the computational efficiency,compared with using directly radiation transfer *** also studied the sensitivity of various input parameters to photosynthetically active radiation,and found that solar zenith angle and atmospheric aerosols were sensitive PAR *** albedo had some effect on PAR,but water vapor and ozone had minimal impact on PAR.

关键词： Photosynthetically active radiation 6S HJ-1A/B satellites

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Temporal-spatial variations of euphotic depth of typical lake regions in Lake Taihu and its ecological environmental significance

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Science China earth sciences 2006年第4期49卷 431-442页

作者： ZHANG Yunlin1, 2, QIN Boqiang1, HU Weiping1, WANG Sumin1, CHEN Yuwei1 & CHEN Weimin1 1. Nanjing Institute of Geography & Limnology, Chinese Academy of sciences, Nanjing 210008, China 2. Graduate School of the Chinese Academy of sciences, Beijing 100039, China Nanjing Institute of Geography & Limnology Chinese Academy of Sciences Nanjing China Graduate School of the Chinese Academy of sciences Beijing China

By using the data of underwater irradiance measured in the different lake regions of Lake Taihu during 1998-2004 and total suspended solids (TSS), wind speeds of the total 13 stations in typical lake regions during 1993-2003, this paper analyzes the factors of influencing on PAR (pho- tosynthetically available radiation) attenuation, euphotic depth, and presents the temporal and spatial variations of euphotic depth of typical lake regions in Lake Taihu, and the spectral distributions of euphotic depth at station 2. The results show that the concentration of TSS is the most important factor impacting PAR attenuation, followed by chlorophyll a; chromophoric dissolved organic matter (CDOM) has little impact on the PAR euphotic depth. During 1993-2003, the mean yearly PAR eu- photic depths of the typical lake regions ranged from 1.04 to 1.95 m with a mean value of 1.35±0.23 m. The PAR euphotic depth fell into 3 spatial zone types: Type I, the lowest, including the lake center and the inflows of rivers; Type II, intermediate, including Meiliang Bay, Wulihu Lake and Gonghu Bay; Type III, the greatest, including the East Lake Taihu; corresponding mean depths were approximately 1.1, 1.4, 2.0 m, respectively. The seasonal variations of euphotic depths were not quite the same in different lake regions. In the lake center, the mean values of PAR euphotic depth in summer and au- tumn were significantly greater than those in winter and spring; in the Meiliang Bay, winter means were significantly greater than in the other three seasons; in the East Lake Taihu, winter means were significantly less than in the other three seasons. However, no distinct seasonal change was recorded in the Wulihu Lake, Gonghu Bay and the inflows of rivers. The spectral distributions of euphotic depth present a minimal value at the blue light wave band of 400 nm, and a peak at the green light wave band of around 580 nm. In 1998 and 1999, based on the seasonal many-day continuous measure- ments, the PAR

关键词： Lake Taihu, euphotic depth, diffuse attenuation coefficient, total suspended solid, ecological environmental significance.

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