期刊文献+
共找到8篇文章
< 1 >
每页显示 20 50 100
THE EXISTENCE OF INFINITELY MANY SO UTIONS OF QUASILINEAR PARTIAL DIFFERENTIAL EQUATIONS IN UNBOUNDED DOMAINS 被引量:1
1
作者 李工宝 《Acta Mathematica Scientia》 SCIE CSCD 1989年第2期175-188,共14页
In this paper, we use the concentration-compactness principle together with the Mountain Pass Lemma to get the existence of nontrivial solutions and the existence of infinitely many solutions of the problem need not b... In this paper, we use the concentration-compactness principle together with the Mountain Pass Lemma to get the existence of nontrivial solutions and the existence of infinitely many solutions of the problem need not be compact operators from E to R~1. 展开更多
关键词 THE EXISTENCE OF INFINITELY MANY SO utions OF QUASILINEAR PARTIAL DIFFERENTIAL EQUATIONS IN UNBOUNDED DOMAINS
在线阅读 下载PDF
Rural Environmental Pollutions and Countermeasures Research in Fengxiang County,Shaanxi Province
2
作者 赵绍梅 王玉 +4 位作者 田宇芳 王宁馨 常慧 张明明 杨子 《Agricultural Science & Technology》 CAS 2014年第10期1816-1818,共3页
With economy develops, rural modernization and urbanization proceed faster in China, and environment issue increasingly draws attention. ln order to ex-plore rural environment contamination, the research made survey a... With economy develops, rural modernization and urbanization proceed faster in China, and environment issue increasingly draws attention. ln order to ex-plore rural environment contamination, the research made survey and interview in Shijiaying and Daxin Vil ages in Fengxiang County, Shaanxi Province. Based on the results, the research analyzed environment pol ution in surveyed vil ages and dis-cussed pol ution causes, with countermeasures proposed. 展开更多
关键词 COUNTRYSIDE Environmental pol ution COUNTERMEASURES Sustainable development
在线阅读 下载PDF
Investigation and Analysis of Soil Pb Contamination at Two Sides of Arterial Traffic in Yellow River Delta Area 被引量:3
3
作者 姚志刚 刘俊华 《Agricultural Science & Technology》 CAS 2016年第12期2722-2725,共4页
[Objective] This study was conducted to investigate soil heavy metal Pb pol ution level and spatial distribution characteristics at two sides of arterial traffic in Yel ow River delta area. [Method] Soil samples were ... [Objective] This study was conducted to investigate soil heavy metal Pb pol ution level and spatial distribution characteristics at two sides of arterial traffic in Yel ow River delta area. [Method] Soil samples were col ected by sample-plot sur-vey method, and soil Pb pol ution condition in road area of Yel ow River delta was determined and analyzed by atomic absorption spectrometry. [Result] Pb pol ution at two sides of national road G205 and provincial road S312 was mainly from auto-mobile exhaust, and Pb content in soil decreased with the distance from road in-creasing. Soil samples col ected at points with distances in the range of 1-50 m from truck road of G205 was 32.46-86.04 mg/kg, which was 1.2-3.3 times of soil Pb background value in this area, and the pol ution was more remarkable. Further study showed that green belt aside road could effectively reduce soil Pb pol ution level. [Conclusion] This study provides theoretical basis and basic information for in-vestigation of soil heavy metal Pb pol ution level and spatial distribution characteris-tics at two sides of arterial traffic in Yel ow River delta area. 展开更多
关键词 Pb pol ution SOIL Arterial traffic Spatial distribution
在线阅读 下载PDF
Soil Environmental Quality Evaluation for Wasteland of Coalmine Tailing Polluted by Heavy Metals in Mingshan of Guangdong 被引量:1
4
作者 刘德良 杨期和 《Agricultural Science & Technology》 CAS 2014年第10期1759-1763,共5页
ln order to appraise scientifical y the heavy metal contamination in waste-land of coalmine tailing in Mingshan of Guangdong, the 5 soil samples in wasteland of coalmine tailing were col ected in November 2010 to Marc... ln order to appraise scientifical y the heavy metal contamination in waste-land of coalmine tailing in Mingshan of Guangdong, the 5 soil samples in wasteland of coalmine tailing were col ected in November 2010 to March 2011. The 7 heavy metals content in the contaminated soil was measured by atomic absorption spec-trophotometry. The results showed the pH of the wasteland soil ranged from 2.87 to 6.16, and the soil was relatively infertile. The soil was mainly pol uted by Cd and Mn. The Cd content in wasteland soil ranged from 0.759 mg/kg to 3.109 mg/kg with an average content of 2.052 mg/kg, which was much higher than the standard content. The Mn content ranged from 387.057 to 488.660 mg/kg with an average content of 421.215 mg/kg, which was much higher than the standard content. The Nemerow integrated pol ution indexes showed the sample 1, sample 4 and sample 5 were of heavy pol ution, and sample 2 and sample 3 were of moderate pol ution. 展开更多
关键词 Heavy metal pol ution Wasteland of coalmine tailing Environmental quality evaluation Coalmine in Mingshan of Guangdong
在线阅读 下载PDF
Dynamic Analysis on Organic Matter and Nitrogen Pollution of Dongchang Lake
5
作者 翟胜 王东丽 +5 位作者 肖栋梁 韩婷 江振 齐永强 周建伟 王巨媛 《Agricultural Science & Technology》 CAS 2014年第8期1390-1394,1402,共6页
The aim was to explore dynamic changes of organic matter and nitrogen pol ution in Dongchang Lake. [Method] Monitoring data, including BOD5, CODCr, NH3-N and TN, of Dongchang Lake were chosen for analysis during 2002-... The aim was to explore dynamic changes of organic matter and nitrogen pol ution in Dongchang Lake. [Method] Monitoring data, including BOD5, CODCr, NH3-N and TN, of Dongchang Lake were chosen for analysis during 2002-2011. [Result] Water quality of the six lake districts showed deteriorating in monitor-ing period, and TN was the dominant pol ution factor; BOD5/CODCr ratio was low, suggesting biodegradability of organic pol utant in the lake was lower. NH3/TN ratio was higher, indicating NH3-N was a major factor causing nitrogen exceeding in 2010. In addition, correlations between BOD5 and CODCr and between NH3-N and TN in the lake districts maintained at a significant level. [Conclusion] The research provides references for improving water in Dongchang Lake. 展开更多
关键词 Dongchang Lake Organic pol utant Nitrogen pol ution Dynamic trend Correlation analysis
在线阅读 下载PDF
SPACE-TIME TEXTURE AND TECTONIC EVOLUTION OF QAMDO BLOCK IN EAST TIBET
6
作者 Wang Mingjie, Wang Gaoming 《地学前缘》 EI CAS CSCD 2000年第S1期175-177,共3页
Qamdo block in the east Tibet lay in front of southwestern margin of the Yangtze landmass and was one of many micro\|blocks between the Gondwana and the Eurasia continents .It played an important role in the developme... Qamdo block in the east Tibet lay in front of southwestern margin of the Yangtze landmass and was one of many micro\|blocks between the Gondwana and the Eurasia continents .It played an important role in the development of the multi\|arc\|basin system of the north sector of the Jinsha\|lancang\|nujiang rivers . Space\|time texture of the block reflected the tectonic evolution of the east Tibet and neighbouring areas directly, providing important information for evolutionary history of the east Tethys.1\ Crustal structure of the Qamdo block\;Crustal structure of the Qamdo block is characterized by “double basement and double cover”.By double basement is meant the Middle—Upper Proterozoic crystalline basement and the Lower Paleozoic folded basement. The Middle—Upper Proterozoic crystalline basement is composed of medium\|high\|grade metamorphic biotite\|plagiogneiss, plagioclase\|amphibole schist, nacritid intercalated with (intermediate\|) basic metavolcanite. These rocks are characteristic of strong ductile deformed metamorphic core complex. The zircon of gneiss yields an U\|Pb age of 1680~2200Ma while the basic metavolcanite give a Sm\|Nd age of 1594Ma.The Lower Paleozoic folded basement consists of the Lower Ordovician and Silurian. Basement of the Qamdo block is similar to that of the Yangtze landmass. By double cover we mean two covers consisting of the Upper Paleozoic and Mesozoic, respectively. The Upper Paleozoic is composed of carbonate and clastic rock which were formed from epicontinental to back\|arc basins. The Mesozoic consists of the Upper Triassic—Cretaceous concordant formations which were formed in a back\|arc foreland basin.Sequences of the formations are molasse, neritic carbonate, paralic coal\|bearing rock and terrigenous red clastic rock from the bottom to the top. 展开更多
关键词 EAST TIBET Qamdo BLOCK time\|space TEXTURE structural evol ution
在线阅读 下载PDF
Evolution of Regional Industrial Structure and Characteristics of Pollution Emissions in China 被引量:6
7
作者 王菲 董锁成 +1 位作者 毛琦梁 黄永斌 《Journal of Resources and Ecology》 CSCD 2014年第1期60-67,共8页
We conducted a quantitative analysis of the relationship between the evolution of China’s industrial structure and environmental change. Using the industrial structure characteristic bias index and data from 29 manuf... We conducted a quantitative analysis of the relationship between the evolution of China’s industrial structure and environmental change. Using the industrial structure characteristic bias index and data from 29 manufacturing industries in each province from 1995 to 2010, we described the impact of pollution-emission characteristics of industry structure on the regional environment. The results show that wastewater-discharged characteristic of industrial structure in the northwest and central areas declined from 1995-2010, but this trend has weakened. The industrial structure of southwest and southeast areas had a high level of solid waste discharge and a constantly strengthening trend in SO2 emissions. We also analyzed the growth and recession of each sector in eight regions in China from 1995 to 2010. Among the eight regions, the middle reach of the Yel ow River, and northwest and southwest China had a clear increasing trend of high pol ution industries;the eastern coast, southern coast, middle reach of the Yangtze River and northeastern China did not sustain an increase in high pollution industries. In addition, regression analysis modeling was used to analyze the impact of the evolution of industrial structure on the disparities of regional environmental effects. We found that regional industry structure was closely related to environmental quality, especially for western areas at lower stages of economic development. In the future, all regions must prevent and forefend the risk of environmental pollution in the update and adjustment of industrial structure. 展开更多
关键词 industrial structure industrial structure characteristic bias index characteristics of pol ution emissions regional differences
原文传递
High-resolution Givetian-Frasnian boundary recognition from conodont-chemo-stratigraphic correlation at Liujing, Guangxi, South China 被引量:2
8
作者 江大勇 郝维城 +1 位作者 丁干 白顺良 《Science China Earth Sciences》 SCIE EI CAS 1999年第3期285-291,共7页
The Givetian-Frasnian boundary at Liujing, Guangxi, South China is for the first time recognized and correlated in high resolution using characteristic chemocycles of element abundance fluctuation integrated with cono... The Givetian-Frasnian boundary at Liujing, Guangxi, South China is for the first time recognized and correlated in high resolution using characteristic chemocycles of element abundance fluctuation integrated with conodont biostratignphy. The first appearance of Ancyrodella rotundiloba early form is as a biomarker, and the boundary of lowering fluctuation of element abundance followed by a sequence of characteristic chemocycles with a sequence of cmodonts is as an abiotic auxiliary marker. The error is not more than 0.10 Ma. The study indicates that in a quiet interval, characteristic chemocycles integrated with biomarkers can be used for boundary recognition and regional cormlation in high resolution, and this method has potential for intercontinental correlation 展开更多
关键词 Givetian-Frasnlsn boundary high reso1ution. correlation chemocyle CONODONT
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部