Based on the remote sensing data of GOME and SCIMACHY, the paper analyzes the variation trend, temporal and spatial characteristics of NO 2 column density from Apr. 1996 to Nov. 2009 in Yangtze Delta region. Besides that, seasonal analyses are also taken. In this session, a whole year is divided into dry season and rainy season. In spatial analyses, the paper emphasizes on the difference between NO 2 column density over the land and the sea located in study area. In addition, some comparative analyses are carried out on monthly average data of NO 2 column density and chlorophyll-a (Chl-a) concentration, in order to explore the relationship between the 2 factors and influence of NO 2 in global carbon cycling, as a part of research on global change. The research result shows that: (1) From 1996 to 2009, the NO 2 column density over Yangtze Delta Region increases, with some fluctuation. (2) The value of NO 2 column density has a higher value in the beginning and the end of the year, while it gets lower in the middle of a year. The value that in dry season is apparently higher than that in rainy season. (3)The spatial analyses show that the column density over land is higher than that over sea on average. Though changing consistently, temporal change of column density over land has a little lag behind that over the sea. (4) The spatial distribution pattern of the value in study area is relatively stable. The place in city of Nanjing, almost all of southern part of Jiangsu Province and Shanghai has a high value, and the place with a low value is in southern part of Zhejiang Province and open sea area to the east of Zhejiang Province. The value in other part of study area is moderate. (5) The variation trend of NO 2 column density and Chl-a concentration is almost opposite. Also, it can be proved that there is no linear relationship between the two parameters.
manganese ferrite (mnfe2o4) with rough surface was synthesized by a simple solvothermal method. the average diameter of particles was about 150 nm, and the tubes of rough surface about 10 nm. here, magnetic mnfe2o4 particles with different morphologies (cube, polyhedron and octahedron) were successfully prepared by controlling ctab concentration. both of the samples with different morphologies exhibit ferromagnetic behavior at room temperature. the saturation magnetization (m-s) and coercivity (h-c) of mnfe2o4 with non-smooth surface are 58.7 am-2/kg and 6.23 ka/m, respectively. the particles with rough surface also show good performance in removal of pollutants like congo red (92.4 mg/g), cr-vi (54.4 mg/g), and pb-ii (84.4 mg/g) from waste water by adsorption experiments. because the particles are recollected by magnetic separation, the waste water purification rate can be improved, which expands the applications of magnetic materials.
Polyaniline(PANI) nanofibers doped with perchloric acid(HClO4) were fast synthesized by electrochemical method including cyclic voltammetry(CV),galvanostatic method(GM) and potentiostatic method(PM) on carbon paper. The microstructure,doping level and conductivity of the PANI nanofibers were characterized by scanning electron microscope( SEM),transmission electron microscope( TEM),Fourier transform infrared spectroscopy( FTIR) and four-probe conductivity meter. The electrochemical property of PANI nanofibers was analyzed by cyclic voltammetry plot. The SEM and TEM images show that,PANI nanofibers have a diameter of 50—150 nm,length of 3 μm,the aspect ratio of 60. The synthetic rate of PANI nanofibers is fastest when synthesised by GM,followed by CV and PM. Compared with the PANI nanofibers synthesized by the other two method,the PANI nanofibers synthesized by CV exhibit the more outstanding conductivity,5. 97 S /cm. FTIR results indicate that the PANI appear strong absorption peaks at 817,1122,1290,1444,1491 and 1567 cm- 1,each peak corresponds with certain structural units of polyaniline,and the PANI synthesized by CV and GM have higher doping level. The CV curves indicates that the PANI nanofibers synthesized by GM exhibit the highest specific capacitance of 578 F /g,followed by PM and CV,which can be used as electrode materials of high-performance supercapacitor.
Abstract In this work, surface modification technique with coupling agents and anchoring polymerization was adopted to tailor the surface properties of nanoscaled titanium dioxide (TiO 2 ). Ethyl glycol sols with TiO 2 were prepared in order to simulate the dispersibility of differently modified TiO 2 in a molten polyamide 6 (PA6) matrix. The modified TiO 2 were melt compounded with PA6 and composites and fibers were prepared. The average filler diameter of 47 nm (in composites) and 44 nm (in fibers) indicated homogeneous dispersion of TiO 2 in the matrix, whereas unmodified TiO 2 showed agglomerated structures in the PA6 matrix. The mechanical properties of the composite fibers were improved as compared to pure PA6 fibers and composite fibers with unmodified TiO 2 .
Rechargeable Li-CO2 batteries have been studied extensively as an attractive strategy for simultaneous energy storage and CO2 fixation to address the global environmental and energy crisis. However, state-of-the-art Li-CO2 systems still suffer from unsatisfactory performance. Here, we successfully exfoliated quinone-based covalent organic frameworks (COFs) into large-scale and ultrathin MnO2/2,6-diaminoanthraquinone-2,4,6-triformylphloroglucinol (DQTP)-COF-nanosheet (NS) hybrid materials. The obtained ultrathin nanosheets (as thin as 1.87 nm) synergistically integrate quinone-COF-NSs with MnO2 and serve as powerful cathode catalysts in Li-CO2 batteries. MnO2/DQTP-COF-NS-3 has a high discharge capacity of 42,802 mAh/g at 200 mA/g. Additionally, it is durable for higher-stress test with a negligible change of overpotential from 500 to 1,000 mA/g and is discharged/charged rapidly for 120 cycles at 1 A/g. Moreover, the CO2 activation mechanism is discussed and supported by density functional theory (DFT) calculations. This work may pave a new way for exploring porous crystalline materials as efficient cathode catalysts for Li-CO2 batteries.
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