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131.
基于空间信息技术的呼伦湖流域研究 总被引:1,自引:0,他引:1
通过对干涉雷达技术任务(SRTM)数据处理,运用土壤与水评价工具(SWAT)模型对呼伦湖整个流域的数字高程模型(DEM)进行水文特征提取,分析流域地形分布情况。呼伦湖全流域面积约为25.6万km2,蒙古国部分约为16.3万km2,约占总面积的63.7%。坡度为0~2.0°的地形主要分布在中国境内的呼伦湖南岸和东岸以及贝尔湖周边的平坦草原上,降雨主要被植被截留和土壤吸收,产汇流条件差;而呼伦湖的主要水源、产汇流条件较好的克鲁伦河和乌尔逊河,其产流区大部分位于蒙古国。2国应加强流域综合管理,合理配置水资源,以保证下游入湖的水量来防止呼伦湖的持续萎缩。 相似文献
132.
采用浸渍法制备了CuO/BiVO4光催化剂,通过X射线衍射(XRD)、热重/差示扫描量热(TG/DSC)和傅立叶红外光谱(FTIR)对其进行了表征,并在可见光照射下考察了其光催化氧化亚甲基蓝(MB)的动力学特性。结果表明,Cu的掺杂并未改变BiVO4的晶型结构;Cu(NO3)2/BiVO4在热处理(30~300℃)过程中,NO3-已经完全分解,Cu最终以CuO的形式存在于CuO/BiVO4光催化剂体系中;掺杂不同量Cu的CuO/BiVO4中的Cu2+/Bi+(摩尔比)实测值与理论值相近,该系列光催化剂的合成过程具有较高的可信度;在可见光照射下,CuO/BiVO4光催化降解MB反应符合表观一级反应动力学特征;当Cu2+/Bi+为0.050时,反应动力学速率常数(k)达到最高值(0.4334h-1),此时的k比单体BiVO4作用下的提高了1.04倍;由于异质结的存在,CuO/BiVO4与单体BiVO4相比,电子和空穴的利用率大大增加,使得CuO/BiVO4的光催化活性较单体BiVO4有了大幅度提高。 相似文献
133.
Chuan-Yao Lin C.-C. Chang C.Y. Chan C.H. Kuo W.-C. Chen D. Allen Chu Shaw C. Liu 《Atmospheric environment (Oxford, England : 1994)》2010,44(2):182-193
To quantify the possible sources of the high ambient ozone concentration in the low troposphere over Taiwan, ozone sounding data from a two-year intensive field measurement program conducted in April and early May of 2004 and 2005 in northern Taiwan has been examined. We found that the vertical ozone distributions and occurrence of enhanced ozone in the lower troposphere (below 6 km) mainly resulted from (1)Type NE: the long-range transport of ozone controlled by the prevailing northeasterly winds below 2 km, (2)Type LO: the local photochemical ozone production process, and (3)Type SW: the strong southwest/westerly winds aloft (2–6 km). In the boundary layer (BL), where Asian continental outflow prevails, the average profile for type NE is characterized by a peak ozone concentration of nearly 65 ppb at about 1500 m altitude. For type LO, high ozone concentration with an average ozone concentration greater than 80 ppb was also found in the BL in the case of stagnant atmospheric and sunny weather conditions dominated. For type SW, significant ozone enhancement with average ozone concentration of 70–85 ppb was found at around 4 km altitude. It is about 10 ppb greater than that of the types NE and LO at the same troposphere layer owing to the contribution of the biomass burning over Indochina. Due to Taiwan's unique geographic location, the complex interaction of these ozone features in the BL and aloft, especially features associated with northeasterly and south/southwesterly winds, have resulted in complex characteristics of ozone distributions in the lower troposphere over northern Taiwan. 相似文献
134.
Jasper Lewis Russell De Young Richard Ferrare D. Allen Chu 《Atmospheric environment (Oxford, England : 1994)》2010,44(35):4510-4520
Aerosol distributions from two aircraft lidar campaigns conducted in the California Central Valley are compared in order to identify seasonal variations. Aircraft lidar flights were conducted in June 2003 and February 2007. While the ground PM2.5 (particulate matter with diameter ≤ 2.5 μm) concentration was highest in the winter, the aerosol optical depth (AOD) measured from the MODIS and lidar instruments was highest in the summer. A multiyear seasonal comparison shows that PM2.5 in the winter can exceed summer PM2.5 by 68%, while summer AOD from MODIS exceeds winter AOD by 29%. Warmer temperatures and wildfires in the summer produce elevated aerosol layers that are detected by satellite measurements, but not necessarily by surface particulate matter monitors. Temperature inversions, especially during the winter, contribute to higher PM2.5 measurements at the surface. Measurements of the mixing layer height from lidar instruments provide valuable information needed to understand the correlation between satellite measurements of AOD and in situ measurements of PM2.5. Lidar measurements also reflect the ammonium nitrate chemistry observed in the San Joaquin Valley, which may explain the discrepancy between the MODIS AOD and PM2.5 measurements. 相似文献
135.
136.
丁生 《长江流域资源与环境》2010,19(Z2):6
曲靖市在滇中城市群大经济圈构建中具有资源丰富,基础资源水、土组合较佳,人均拥有量相对较多,能源优势突出的特点。这些使得曲靖市在滇中城市群发展中起着十分关键的作用,曲靖是滇中城市群农业、能源和重化工工业基地,其资源环境基础是促进滇中城市群快速、稳步、健康、高效发展的发动机和加速器。同时也应看到,一些矿产资源不足及作为生态保障的森林资源不足是其发展的限制因素,加之长期的消耗也使曲靖市面临水土流失和煤大量消耗而产生酸雨等严重的生态压力,人地关系呈现紧张状态。分析曲靖市资源环境基础情况,可以为曲靖市和滇中城市群快速、稳步、健康、高效的发展和相关政策的制定提供参考。〖 相似文献
137.
Sheng‐Suan Cai John D. Stark 《Journal of environmental science and health. Part. B》2013,48(6):985-1004
Abstract A fluorescent method for the determination of rhodamine B (RhB) and brilliant sulfaflavine (BSF) dual tracers on cotton string collectors and in spray tank solutions was developed for the evaluation of the effects of adjuvants on the atmospheric drift of agricultural sprays. Both tracers on collectors were extracted with deionized water simultaneously and measured directly with a Fluorescent Specrometer by switching the maximum excitation and emission wavelengths. The linear ranges of the RhB and BSF standard curves were 0–50 and 0–10 ppb respectively. Recoveries of tracers on cotton strings ranged from 92.9% ± 1.1% to 95.1% ± 1.0% for RhB and 91.9% ± 2.8% to 103% ± 0.6% for BSF when spiked levels ranged from 0.25 to 2.5 μg per collector. The detection limit of the instrument was approximately 0.1 ppb for both tracers. The detection limits of the analytical method were approximately 0.1 ppb for RhB and 0.3 ppb for BSF when the background levels of cotton strings were subtracted. The presence of one tracer in the solution did not significantly interfere with the detection of the other tracer in the same solution. The presence of adjuvants added to the spray tank solutions did not interfere with the detection of both tracers when the adjuvants were applied at the manufacturer's maximum recommendation rates. 相似文献
138.
Hong-Guang Guo Nai-Yun Gao Wen-Hai Chu Lei Li Yong-Ji Zhang Jin-Shan Gu Yu-Liang Gu 《Environmental science and pollution research international》2013,20(5):3202-3213
Photochemical degradation of fluoroquinolone ciprofloxacin (CIP) in water by UV and UV/H2O2 were investigated. The degradation rate of CIP was affected by pH, H2O2 dosage, as well as the presence of other inorganic components. The optimized pH value and H2O2 concentration were 7.0 and 5 mM. Carbonate and nitrate both impeded CIP degradation. According to liquid chromatography–tandem mass spectrometry analysis, four and 16 products were identified in UV and UV/H2O2 system, respectively. Proposed degradation pathways suggest that reactions including the piperazinyl substituent, quinolone moiety, and cyclopropyl group lead to the photochemical degradation of CIP. Toxicity of products assessed by Vibrio qinghaiensis demonstrated that UV/H2O2 process was more capable on controlling the toxicity of intermediates in CIP degradation than UV process. 相似文献
139.
Qinsong Xu Han Qiu Weiyue Chu Yongyang Fu Sanjuan Cai Haili Min Sha Sha 《Environmental science and pollution research international》2013,20(12):8672-8679
Laboratory experiments were conducted to investigate copper (Cu) subcellular distribution and toxicity in Hydrilla verticillata. Fronds were subjected to different concentrations (15, 75, and 150 μM) of Cu for 7 days. Cu grains were found in cell walls, plasmodesmata, and within the nuclei and chloroplasts using the autometallographic technique. Subcellular fractionation of Cu-containing tissues indicated that in leaves subjected to high Cu concentrations, 59–65 % of the element was located in the cell wall fraction, followed by cell organelles (21–30 %) and the soluble fraction (10–14 %). The levels of K, P, Zn, and Mg declined under all Cu concentrations, but Ca, Mn, and Fe contents reached their peak at 15 μM Cu and decreased thereafter. F v/F m, F 0, and F m fell significantly in line with the decrease in pigment content. Cu exposure also caused significant damage to the chloroplasts, mitochondria, and nuclei, including disintegration of the chloroplasts and vacuolization of the mitochondria and nuclei, all of which suggested that Cu hastened plant senescence. The Cu maximum permissible concentration for H. verticillata was 10 μM, which was less than the existing general water quality standard. This suggested that H. verticillata could be used to assess Cu phytotoxicity. 相似文献
140.
The interactions between metals (Ca2+ and Hg2+) and extracellular polymeric substances (EPS) extracted from the aerobic and anaerobic sludge in wastewater treatment reactors were investigated using a combination of zeta potential measurement and 3-dimensional excitation–emission matrix (EEM) fluorescence spectroscopy with parallel factor (PARAFAC) analysis. Results show that Ca2+ had no substantial effects on the EEM fluorescence spectra of the EPS, but their zeta potentials increased with the increasing Ca2+ dosage. However, Hg2+ had a significant effect on the EEM fluorescence spectra of the EPS, while their zeta potentials seemed not to be affected by the dose of Hg2+. The interactions between Hg2+ and EPS were elucidated using the fluorescence quenching with PARAFAC analysis, while the interactions between Ca2+ and EPS were evaluated by the zeta potential technique. The binding constants for Hg2+ and EPS were two orders of magnitude higher than those for Ca2+ and EPS, suggesting that the binding mechanisms between Ca2+ and EPS were different from those between Hg2+ and EPS. The results might be useful for understanding the roles of EPS in bacterial self-protection against heavy metals and the aggregate formation mechanisms through ionic bridging interactions. 相似文献