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861.
BiFeO_3–g-C_3N_4 nanoscaled composite was prepared with a hydrothermal method and evaluated as a highly efficient photo-Fenton like catalyst under visible light irradiation. The BiFeO_3–g-C_3N_4 composite exhibited much stronger adsorption ability to lignin model pollutant(guaiacol) than that of BiFeO_3, which may be due to the higher specific surface area(BiFeO_3–g-C_3N_4: 35.59 m~2/g BiFeO_3: 7.42 m~2/g) and the adsorption form of π–π stack between g-C_3N_4 and guaiacol. The composite exhibited excellent visible light-Fenton like catalysis activity, being influenced by the solution pH value and the proportions of BiFeO_3 and g-C_3N_4 nanosheets. Under optimal conditions with visible light irradiation, the BiFeO_3–g-C_3N_4 composite yielded fast degradation of guaiacol with an apparent rate constant of 0.0452 min~(-1), which were 5.21 and 6.80 folds of that achieved by using BiFeO_3 and the mixture of BiFeO_3 and g-C_3N_4 nanosheets, respectively. The significantly enhanced visible light-Fenton like catalytic properties of the BiFeO_3–g-C_3N_4 composite in comparison with that of BiFeO_3 was attributed to a large surface area, much increased adsorption capacity and the semiconductor coupling effect between BiFeO_3 and g-C_3N_4 in the composite. 相似文献
862.
雌激素受体(Estrogen Receptor,ER)ERα和ERβ能与雌激素特异性结合,它们在结构上的差异性可能影响与类雌激素的相互作用,这进而会影响其功能.因此,针对10种有机磷农药对ERα和ERβ的雌激素效应差异,采用分子对接方法比较分析了它们与ERα、ERβ相互作用的差异并筛选出与ERα和ERβ相互作用的最佳结合模式.结果发现,10种有机磷农药分子与ERα配体结合域(Ligand Binding Domain,LBD)精氨酸(Arg394)、赖氨酸(Lys449)、色氨酸(Trp393)形成氢键;而部分农药分子与ERβLBD精氨酸(Arg346)、亮氨酸(Leu343)、赖氨酸(Lys401)形成氢键.有机磷农药配体与ERαLBDArg394、Lys449、苯丙氨酸(Phe445)、脯氨酸(Pro324)、Leu387、谷氨酸(Glu353)、甘氨酸(Gly390)等存在疏水作用,与ERβLBD氨基酸Arg346、Glu305、Leu343、蛋氨酸(Met336)、组氨酸(His279)、丙氨酸(Ala302)等存在疏水作用.采用量子化学从头算进一步分析了10种有机磷农药分子表面静电势的差异.研究发现,有机磷农药分子与ERα和ERβ受体不同的相互作用是导致雌激素效应差异的重要原因. 相似文献
863.
864.
865.
CO2 capture by electrothermal swing adsorption is considered superior over conventional adsorption approaches: temperature swing adsorption and pressure swing adsorption. In this work, the effects of electricity, preheating and flow rate were studied. An increase in energy input by electricity has been found able to improve desorption performance more significantly than an increase in current level. However, higher current level is recommended because it can minimise energy loss while passing electricity. Higher flow rate can also be beneficial due to the improved desorption rate and reduced desorption time. However, there is a drop in CO2 concentration in the effluent gas. When desorption takes place at a high current level, preheating is not required as it extends desorption duration with no obvious improvement in desorption rate. CO2 capture by electrothermal swing adsorption has also been tested with different concentrations of CO2. It is found that electrothermal swing adsorption can be more energy efficient while dealing with higher concentration CO2. 相似文献
866.
This study investigated allelopathy and its chemical basis in nine switchgrass (Panicum virgatum L.) accessions. Perennial ryegrass (Lolium perenne L.) and alfalfa (Medicago sativa L.) were used as test species. Undiluted aqueous extracts (5 g plant tissue in 50 ml water) from the shoots and roots of
most of the switchgrass accessions inhibited the germination and growth of the test species. However, the allelopathic effect
of switchgrass declined when extracts were diluted 5- or 50-fold. Seedling growth was more sensitive than seed germination
as an indicator of allelopathic effect. Allelopathic effect was related to switchgrass ecotype but not related to ploidy level.
Upland accessions displayed stronger allelopathic potential than lowland accessions. The aqueous extract from one switchgrass
accession was separated into phenols, organic acids, neutral chemicals, and alkaloids, and then these fractions were bioassayed
to test for allelopathic potential. Alkaloids had the strongest allelopathic effect among the four chemical fractions. In
summary, the results indicated that switchgrass has allelopathic potential; however, there is not enough evidence to conclude
that allelopathic advantage is the main factor that has contributed to the successful establishment of switchgrass on China’s
Loess Plateau. 相似文献
867.
Junyeong An Soo-Jin Lee How Yong Ng In Seop Chang 《Journal of environmental management》2010,91(12):2478-2482
We examined the possibility of harvesting electricity from the surface of a tidal mud flat using a cylindrical-type sediment microbial fuel cell (SMFC), a marine mud battery (MMB), which can be applied in a sea environment where the ebb and flow occur due to tidal difference. In addition, we indirectly investigated the influence of ebb and flow in a lab, using aeration, argon gassing, and by agitating the cathodic solution. The MMBs consisted of cylindrical acrylic compartments containing a nylon membrane, an anode, and a cathode in a single body. The MMBs were stuck vertically into an artificial tidal mud flat such that the anode electrode was in direct contact with the tidal mud surface. As a result, the maximum current and power density generated were 35 mA/m2 and 9 mW/m2, respectively, thus verifying that it is possible to harvest electricity from the surface of a tidal mud flat using an MMB without burying the anode electrode in the tidal mud. Furthermore, the results of tests using an artificial turbulence flow showed the flow induced by the tidal ebb and flow could allow the performance of MMBs to be enhanced. 相似文献
868.
The present study identified creative role identity and job autonomy as two moderators that influence the relationship between benevolent leadership, a leadership style that prevails in paternalistic contexts, and creativity. Using 167 dyads of supervisor and subordinate as a sample, we found that both creative role identity and job autonomy have significant moderating effects: When each moderator is high, the positive relationship between benevolent leadership and creativity is stronger; when each moderator is low, this relationship is weaker. Our results suggest that the effect of benevolent leadership upon creativity is dependent on the coexistence of important individual and contextual factors. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
869.
Assessing the impact of urbanization on regional net primary productivity in Jiangyin County, China 总被引:2,自引:0,他引:2
Urbanization is one of the most important aspects of global change. The process of urbanization has a significant impact on the terrestrial ecosystem carbon cycle. The Yangtze Delta region has one of the highest rates of urbanization in China. In this study, carried out in Jiangyin County as a representative region within the Yangtze Delta, land use and land cover changes were estimated using Landsat TM and ETM+ imagery. With these satellite data and the BEPS process model (Boreal Ecosystem Productivity Simulator), the impacts of urbanization on regional net primary productivity (NPP) and annual net primary production were assessed for 1991 and 2002. Landsat-based land cover maps in 1991 and 2002 showed that urban development encroached large areas of cropland and forest. Expansion of residential areas and reduction of vegetated areas were the major forms of land transformation in Jiangyin County during this period. Mean NPP of the total area decreased from 818 to 699 gCm(-2)yr(-1) during the period of 1991 to 2002. NPP of cropland was only reduced by 2.7% while forest NPP was reduced by 9.3%. Regional annual primary production decreased from 808 GgC in 1991 to 691 GgC in 2002, a reduction of 14.5%. Land cover changes reduced regional NPP directly, and the increasing intensity and frequency of human-induced disturbance in the urbanized areas could be the main reason for the decrease in forest NPP. 相似文献
870.
Xin Zhang Zhongzhi Zhang Zhisheng Xiao Guigang Tang Hong Li Rui Gao Xu Dao Yeyao Wang Wenxing Wang 《环境科学学报(英文版)》2022,34(4):170-178
To investigate the characteristics of particulate matter with an aerodynamic diameter less than 2.5 μm (PM2.5) and its chemical compositions in the Beijing-Tianjin-Hebei (BTH) region of China during the novel coronavirus disease (COVID-19) lockdown, the ground-based data of PM2.5, trace gases, water-soluble inorganic ions, and organic and elemental carbon were analyzed in three typical cities (Beijing, Tianjin, and Baoding) in the BTH region of China from 5-15 February 2020. The PM2.5 source apportionment was established by combining the weather research and forecasting model and comprehensive air quality model with extensions (WRF-CAMx). The results showed that the maximum daily PM2.5 concentration reached the heavy pollution level (>150 μg/m3) in the above three cities. The sum concentration of SO42−, NO3− and NH4+ played a dominant position in PM2.5 chemical compositions of Beijing, Tianjin, and Baoding; secondary transformation of gaseous pollutants contributed significantly to PM2.5 generation, and the secondary transformation was enhanced as the increased PM2.5 concentrations. The results of WRF-CAMx showed obviously inter-transport of PM2.5 in the BTH region; the contribution of transportation source decreased significantly than previous reports in Beijing, Tianjin, and Baoding during the COVID-19 lockdown; but the contribution of industrial and residential emission sources increased significantly with the increase of PM2.5 concentration, and industry emission sources contributed the most to PM2.5 concentrations. Therefore, control policies should be devoted to reducing industrial emissions and regional joint control strategies to mitigate haze pollution. 相似文献