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391.
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浙赣皖相邻地区燕山期大茅山、铜山、里山岭、黄山、伏岭等岩体主要由黑云母花岗岩组成,其中斜长石属钠长石和富钠更长石,黑云母呈它形填隙状,结晶晚于浅色矿物。岩石化学成分富SiO_2(73.92%-77.55%)、富碱(Na_2O+K_2O为7.81%~8. 67%),贫CaO(0.26%-0.92%)、MgO(0—0.45%);微量元素中富集Y、Nb、Zr等HFSE,贫过渡元素及Sr、Ba;稀土配分曲线呈“海鸥型”。这些特点与区内及华南I型和S型花岗岩明显不同,而具有A_2型花岗岩的典型特征。 相似文献
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394.
以水环境功能区区划为基础,进行了丹河流域水系特征、水文特征和入河污染源现状调查,在此基础上,对丹河流域各排污口的排放量及污染物进行分析,以流域各功能区应达到的水质目标和恢复其应有的自然功能为依据,建立一雏稳态条件下水环境容量计算两种的模型:完全混合水环境容量模型解析解和非线性衰减、多点容量计算模型,计算出流城内水环境容量。以此为依据可对排入丹河污染物的量进行控制,为总量控制提供了较适用的方法。 相似文献
395.
分别用溴化十六烷基三甲铵(CTMAB)和氯化十六烷基吡啶(CPC)改性膨润土,研究了制备有机膨润土的适宜条件及其对吸附对对硝基苯酚性能的影响。25℃时,CTMB-膨润土和CPC-膨润土对对硝基苯酚的饱和吸附量分别为475mg/g,远大于原土的饱和吸附量(125mg/g)。pH〉7时,有机膨润土吸附处理对硝基苯酚的去除率都在85%以上,比原土的去除率(8.6%)大9倍,通过X-衍射、红外光谱分析、比 相似文献
396.
Anyun Zhang Zunfang Tu Junrui Shui Jinxin Liu Hongmei Tuo Haoyu Zhang Cong Lin Jingyi Feng Yuxuan Feng Wen Su 《环境科学学报(英文版)》2023,35(2):462-471
Plasmids play a critical role in the dissemination of antimicrobial resistance genes (ARGs), however, a systematical understanding of ARGs originated from plasmids in swine production is currently lacking. Herein, quantitative polymerase chain reaction was applied to determine the prevalence of ten ARGs and the class1 integron gene intI1 of plasmid source in swine manure from 44 farms in Sichuan, Hubei and Hebei provinces, China. All assayed ARGs were observed in plasmid DNA samples, and the average absolute abundance of aac(6’)-Ib-cr, blaNDM, blaCTX-M, optrA, ermB, floR, mcr-1, qnrS, tetM, sul1 and intI1 were 7.09, 2.90, 4.67, 6.62, 7.55, 7.14, 4.08, 4.85, 7.16, 7.11 and 8.07 of 10 log copies/gram, respectively. IntI1 showed a high correlation (r > 0.8, P < 0.01) with the abundance of aac(6’)-Ib-cr and sul1 in swine manure. Moreover, the farm scale (i.e., herd population) and geographical location were not found to be critical factors influencing the absolute abundance of ARGs of plasmid DNA in swine farms. However, the concentrations of florfenicol, Cu, Zn, Fe, total phosphorus (TP) and total potassium (TK) demonstrated a significant correlation with the abundance of several ARGs. Particularly, Cu and Zn had high correlations with optrA and blaCTX-M, respectively. Our results demonstrated that antibiotics, heavy metals and environmental nutrients are likely jointly contributing to the long-term persistence of ARGs in swine production. This study provides insights into the abundance and influencing factors of ARGs from swine manure, which is of significance for assessing and reducing the public health risks in livestock production. 相似文献
397.
A photoelectrochemical process in the degradation of an azodye(Acid Orange II)on a Pt/TiO2 film electrode was investigated.By using the glass device and the voltage stabilized source of direct current,decolorization ratios higher than 78% were observed during a period of 5h.Comparing this value with the sum of the decolorization ratios obtained by a sole application of electrochemical(lower than 3%)and photochemical(about 23%)procedures, a significant synergic effect between both processes was observed.The effects of adscititious voltage and pH value on the decolorization ratios were obvious while the effect of the amount of aeration was minor. 相似文献
398.
自民国迄今,一些政治家、思想家及学者分别从自然科学角度和社会历史角度对民国初年灾荒史予以诠释,依时间而言主要集中于20世纪80年代以后,依内容而言又呈现出一种多元化的态势。其间,虽然取得了一定的成就,诸如积累了一些资料、研究内容多样化等,但仍存在着一些不足。 相似文献
400.
Penghao Su Yuejiao Hao Zhe Qian Weiwei Zhang Jing Chen Fan Zhang Fang Yin Daolun Feng Yingjun Chen Yifan Li 《环境科学学报(英文版)》2020,32(5):262-270
Ship auxiliary engines contribute large amounts of air pollutants when at berth.Biodiesel,including that from waste cooking oil(WCO),can favor a reduction in the emission of primary pollutant when used with internal combustion engines.This study investigated the emissions of gaseous intermediate-volatile organic compounds(IVOCs) between WCO biodiesel and marine gas oil(MGO) to further understand the differences in secondary organic aerosol(SOA) production of exhausts.Results revealed that WCO exhaust exhibited similar IVOC composition and volatility distribution to MGO exhaust,despite the differences between fuel contents.While WCO biodiesel could reduce IVOC emissions by 50% as compared to MGO,and thus reduced the SOA production from IVOCs.The compositions and volatility distributions of exhaust IVOCs varied to those of their fuels,implying that fuel-component-based SOA predicting model should be used with more cautions when assessing SOA production of WCO and MGO exhausts.WCO biodiesel is a cleaner fuel comparing to conventional MGO on ship auxiliary engines with regard to the reductions in gaseous IVOC emissions and corresponding SOA productions.Although the tests were conducted on test bench,the results could be considered as representative due to the widely applications of the test engine and MGO fuel on real-world ships. 相似文献