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31.
秦林芳 《辽宁师范大学学报(社会科学版)》2002,25(6)
浅草———沉钟社在个性主题的创作中 ,形成了三种表现模式。他们在“离乡与回乡的互补”中 ,以决绝的“离乡”喻示个性意识的觉醒 ,以深情的“回乡”表现对都市文明的超越和对理想人性的追求 ;在“童心与成人的对照”中 ,以儿童的圣洁反衬成人世界的污浊 ,显示出自然人性的价值取向 ;在“自然与社会的对立”中 ,以秀丽、雄强的自然景观寓托和谐、强悍的生命形式 ,以反社会的姿态 ,表达了改造社会、实现异化人性复归的强烈愿望。这三种模式特色鲜明 ,从不同角度传达出个性主题的内涵 ,具有深厚的文化意蕴 相似文献
32.
Kasthurirangan Gopalakrishnan 《浙江大学学报(A卷英文版)》2008,9(9):1157-1166
Previous research studies have successfully demonstrated the use of artificial neural network （ANN） models for predicting critical structural responses and layer moduli of highway flexible pavements. The primary objective of this study was to develop an ANN-based approach for backcalculation of pavement moduli based on heavy weight deflectometer （HWD） test data, especially in the analysis of airport flexible pavements subjected to new generation aircraft （NGA）. Two medium-strength subgrade flexible test sections, at the National Airport Pavement Test Facility （NAPTF）, were modeled using a finite element （FE） based pavement analysis program, which can consider the non-linear stress-dependent behavior of pavement geomaterials. A multi-layer, feed-forward network which uses an error-backpropagation algorithm was trained to approximate the HWD back- calculation function using the FE program generated synthetic database. At the NAPTF, test sections were subjected to Boeing 777 （B777） trafficking on one lane and Boeing 747 （B747） trafficking on the other lane using a test machine. To monitor the effect of traffic and climatic variations on pavement structural responses, HWD tests were conducted on the trafficked lanes and on the untrafficked centerline of test sections as trafficking progressed. The trained ANN models were successfully applied on the actual HWD test data acquired at the NAPTF to predict the asphalt concrete moduli and non-linear subgrade moduli of the medium-strength subgrade flexible test sections. 相似文献
33.
Characterization of suspended solids and particle-bound heavy metals in a first flush of highway runoff 总被引：1，自引：0，他引：1
To investigate the dynamic characteristics of total suspended solids （TSS） and their particle-bound heavy metals in a first flush, the runoff sampling together with its flow rate measuring was conducted for three rainfall events at outfalls of highway in Shanghai from June to September 2007. Field samples were analyzed to determine the concentrations of TSS and particle-bound heavy metals, such as Zn, Pb, and Cu. Results show that the wash offbehavior of TSS under varying runoffrate condition can be explained by different antecedent dry weather period （ADWP）. Contribution of fine fraction （〈45 μm） to TSS was generally higher than that of coarse fraction （〉45 μm）. When the runoff flow increased obviously, a significant contribution of the coarse fraction was observed for a certain rainfall events with long antecedent dry weather condition. The changes of total metals concentration and particle-bound metal concentrations were strongly dependent on the TSS variation. TSS was generally well correlated with most particulate-bound heavy metals. Of the heavy metals, the concentration of Zn was found considerably high and that of Pb was significantly low at North Zhongshan 2 Road, in Shanghai, China, but they are still within the range reported in the literature. Fluctuation of heavy metal contents in the coarse fraction during a first flush period was more significant compared with that in the fine fraction. The results will assist in the development of effective control strategies to minimize heavy metals and solids in highway runoff. 相似文献
34.
沉积物中重金属元素的来源及其含量的影响因素 总被引：1，自引：0，他引：1
简要介绍了水体沉积物中重金属元素的主要来源，影响水体沉积物中重金属元素含量的自然因素，其中包括沉积物-水界面环境条件、有机质和微生物活动等。 相似文献
35.
INTRODUCTION Nitrate and heavy metals commonly found ingroundwater pollutants constitute significant healthrisk to humans and a burden on the environment.Mixtures of these compounds often exist in soils andgroundwater at numerous contaminated sites. Highnitrate (NO3 ) levels in drinking water supplies sig- ?nificantly endanger human health, as they are directlyresponsible for methemoglobinemia in infants (bluebaby syndrome) and may play a role in the develop-ment of som… 相似文献
36.
重金属的开采和冶炼不仅破坏生态平衡,而且严重威胁人类的健康。以毕节地区2个铅锌矿为研究对象,采用现场采样、室内分析的方法,调查研究了该地区土壤及优势植物中重金属含量。结果表明：研究区土壤主要受到Pb、Zn、Cu、Cd四种重金属污染,其中,Cd污染最为严重,Pb、Zn为轻度污染。优势植物重金属含量测定表明,野艾蒿属于重金属富集型植物,苦苣菜属于规避型植物,马刺蓟属于根部囤积型植物。以上几种优势植物对重金属均具有一定的耐性,可以作为铅锌矿区弃地植物修复的优选物种。 相似文献
37.
柱撑改性膨润土的制备及吸附性能研究 总被引：1，自引：0，他引：1
天然膨润土进行酸化处理后,对其进行无机、有机和无机有机柱撑,制备出改性膨润土。研究了改性膨润土和天然膨润土对重金属离子Ni2 及苯酚的吸附效果,表明改性膨润土的吸附效果明显优于天然膨润土。 相似文献
38.
Immobilization of heavy metals in sludge using phosphoric acid and monobasic calcium phosphate 总被引：1，自引：0，他引：1
The purpose of this research is to investigate the potential of pre-treatment with phosphoric acid(PA) and monobasic calcium phosphate(MCP) for the stabilization of heavy metals in sludge and its bottom ash.The tannery sludge samples were collected in Wenzhou,China and heavily contaminated with heavy metals,such as Pb,Cr and so on.The samples were pre-treated with PA or MCP.Then XRD and TCLP tests were adopted as the evaluating methods to characterize the Pb,Cr,Cu,Zn and Cd immobilization in the pre-treated sludge and its bottom ash.The results showed that this treatment effectively immobilized Pb and Cd in the sludge,lightly stabilized the metal Cu,and adversely,enhanced the leachability of Zn.After incineration at 900℃,Pb and Cr in the bottom ash of pre-treated sludge were significantly stabilized due to the formation of their highly thermostable phosphates and pyromorphite-like minerals during the incineration process.However,an increase of Cu and Zn solubility was observed which might be attributable to the acidification of sludge due to the addition of PA or MCP. 相似文献
39.
Vitamin C in Disease Prevention and Cure: An Overview 总被引：1，自引：0，他引：1
Shailja Chambial Shailendra Dwivedi Kamla Kant Shukla Placheril J. John Praveen Sharma 《Indian journal of clinical biochemistry : IJCB》2013,28(4):314-328
The recognition of vitamin C is associated with a history of an unrelenting search for the cause of the ancient haemorrhagic disease scurvy. Isolated in 1928, vitamin C is essential for the development and maintenance of connective tissues. It plays an important role in bone formation, wound healing and the maintenance of healthy gums. Vitamin C plays an important role in a number of metabolic functions including the activation of the B vitamin, folic acid, the conversion of cholesterol to bile acids and the conversion of the amino acid, tryptophan, to the neurotransmitter, serotonin. It is an antioxidant that protects body from free radical damage. It is used as therapeutic agent in many diseases and disorders. Vitamin C protects the immune system, reduces the severity of allergic reactions and helps to fight off infections. However the significance and beneficial effect of vitamin C in respect to human disease such as cancer, atherosclerosis, diabetes, neurodegenerative disease and metal toxicity however remains equivocal. Thus further continuous uninterrupted efforts may open new vistas to understand its significance in disease management. 相似文献
40.
INTRODUCTION Biosphere pollution by heavy metals and nu-cleotides was accelerated dramatically during the last few decades due to mining, smelting, manufacturing, treatment of agricultural soils with agro-chemicals and soil sludge, etc. Problems associated with the contamination of soil and water such as animal wel-fare, health, fatalities and disruptions of natural eco-systems are well documented (He et al., 2005). Heavy metals such as Pb, Cr, As, Cu, Cd, and Hg, being added to our so… 相似文献