检索结果-南通市图书馆

Geomorphologic analysis and physico-dynamic characteristics of Zhatai-Gully debris flows in SW China

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2016年第1期13卷 137-145页

作者： liu xi-lin TANG Chuan NI Hua-yong ZHAO Yuan School of Geography and Planning Sun Yat-sen UniversityGuangzhou 510275China State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu 610059China Chengdu Institute of Geology and Mineral Resources China Geological SurveyChengdu 610081China Natural Resoources Science Academy of Sichuan Province Chengdu 610041 China

Zhatai gully is a typical debris flow channel in Butuo county of Sichuan province, southwestern China. The geomorphologic features are analyzed and the physical-dynamic characteristics are discussed on the basis of field investigation and laboratory tests. Geomorphologic analysis indicates that Zhatai-gully drainage in relation to debris flow can be divided into source area, transport area, and deposition area. The source area has a steep slope and has very limited vegetation cover, which favors runoff, allowing loose solid materials to be mobilized easily and rapidly. In the transport area, there are many small landslides, lateral lobes, and loose materials distributed on both banks. These landslides are active and constantly providing abundant source of soils for the debris flows. In the deposition area, three old debris-flow deposits of different ages can be observed. The dynamic calculation shows that within the recurrence intervals of 50 and lOO years, debris flow discharges are 155.77m^3/s and 178.19m^3/s and deposition volumes are 16.39 × 10^4 m^3 and 18.14 × 10^4 m^3, respectively. The depositional fan of an old debris flow in the outlet of the gully can be subdivided into six layers. There are three debris flow deposits on left and two on the right side of the gully. Grain-size tests of sediments from the soil, gulley bed deposits, and the fresh and old debris flow deposits showed that high amounts of clay and fine gravel were derived from the soil in the source area whereas much of the gravel fraction were sourced from the gully bed deposits. Comprehensive analysis indicates that Zhatai gully is viscous debris-flow gully with moderate to high frequency and moderate to large magnitude debris flows. The risk of a debris flow disaster in Zhatai-gully is moderate and poses a potential threat to the planned hydroelectric dam. Appropriate engineering measures are suggested in the construction and protection of the planned hydroelectric station.

关键词： Debris flows Geomorphologic feature Zhatai gully China

Promotion by 5-Aminolevulinic Acid of Germination of Pakchoi （Brassica campestris ssp. chinensis var. communis Tsen et Lee） Seeds Under Salt Stress

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Plant Biology 2005年第9期47卷 1084-1091页

作者： Liang-Ju WANG Wei-Bing JIANG Hui liu Wei-Qin liu Lang KANG xi-lin HOU College of Horticulture Nanjing Agricultural University Nanjing 210095 China

The seed germination and seedling growth of pakchoi （Brassica campestris ssp. chinensis var. communis Tsen et Lee cv. Hanxiao） were not significantly inhibited until the concentration of NaCl was increased to 150 mmol/L. Treatment of pakchoi seeds with exogenous 5-aminolevulinic acid （ALA）, at concentrations ranging from 0.01 to 10.00 mg/L, promoted seed germination when seeds were stressed by salinity, whereas levulinic acid （LA）, an inhibitor of ALA dehydrase, significantly inhibited seed germination and seedling growth, suggesting that metabolism of ALA into porphyrin compounds was necessary for seed germination and seedling growth. Determination of respiratory rate during seed germination showed that ALA increased seed respiration under both normal conditions and salt stress. Furthermore, salt stress decreased levels of endogenous ALA, as well as heme, in etiolated seedlings. More salt-tolerant cultivars of pakchoi contained higher relative levels of endogenous ALA and heme under conditions of salt stress. These results indicate that salt stress may inhibit the biosynthesis of endogenous ALA and then heme, which is necessary for seed germination, and treatment of seeds with exogenous ALA prior to germination may be associated with the biosynthesis of heme.

关键词： 5-aminolevulinic acid (ALA) germination heme pakchoi respiration salt stress.

GULLY-SPECIFIC DEBRIS FLOW HAZARD ASSESSMENT IN CHINA

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Geographical Science 2003年第2期13卷 112-118页

作者： liu xi-lin (Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, C hengdu 610041, P.R. China) Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu P. R. China

Techniques of gully-specific debris flow hazard assessment develope d in four periods since the end of the 1980s have been discussed in the present paper. The improvement for the empirical assessment method is the sectionalized function transformation for the factor value, rather than the classified logical transformation. The theoretical equation of the gully-specific debris flow haz ard is expressed as the definite integral of an exponential function and its num erical solution is expressed by the Poisson Limit Equation. Current methods for assessment of debris flow hazard in China are still valid and practical. The fur ther work should be put on the study of the reliability (or uncertainty) of the techniques. For the future, we should give a high priority to the relationship b etween debris flow magnitude and its frequency of occurrence, make more developm ents of prediction model on debris flow magnitude, so as to finally reach the go al of assessing the hazard of debris flow by theoretical model, and realize both actuality assessment and prediction appraisal of debris flow.

关键词： debris flow hazard gully-specific debris flow assessment theoreticalequation

All-transRetinoic Acid Regulates Th1/Th2 Balance in CD4+T cells When GATA-3 is Deficient

在线全文

学校读者我要写书评

暂无评论

Biomedical and Environmental Sciences 2013年第9期26卷 774-777页

作者： ZHU Yan Feng HU Jia Zhe ZHAO Pin Nan liu lin xi and LI Yun Department of Nutrition and Food Hygiene West China School of Public Health Sichuan University Food and Drug Administration Chengdu Centers for Diseases Control and Prevention

The essential effect of vitamin A on immune function occurs through various mechanisms including direct effect on ThloTh2 balance modulation. However, it is unclear whether or not vitamin A can regulate Thl-Th2 balance under a strong Thl-polarizing condition. Therefore, the purpose of our study was to examine the effect of vitamin A metabolite allotrans retinoic acid （ATRA） on ThloTh2 differentiation in CD4~ T cells under GATA-3 deficiency, which can induce Thl-polarizing condition. In the present study, GATA-3 deficiency T cells were induced by siRNA and checked by real-time quantitative PCR and western blot. GATA-3 deficiency CD4＋ T cells and normal CD4＋ T were treated for 48 h with or without ATRA.

关键词： GATA cell Th All-transRetinoic Acid Regulates Th1/Th2 Balance in CD4+T cells When GATA-3 is Deficient CD

Research on Service-oriented Knowledge Management Model of Multi-campus College and University

在线全文

学校读者我要写书评

暂无评论

International Journal of Plant Engineering and Management 2013年第4期18卷 212-216页

作者： LI Dong liu xi-lin School of Management Northwestern Polytechnical University xi'an Communications Institute

Knowledge management theory is increasingly attracting the attention of colleges and universities, and has become a new perspective to the reform of college management. With the development of education informa tionization, the service orientation will become the main direction in knowledge management. On the fact of many campuses in colleges and universities, this paper presents model based on serviceoriented idea and grid technology, campus university knowledge management. a university knowledge management system framework and discusses the processes of serviceoriented multi

关键词： service oriented knowledge management multi-campus universities management mode

Customer Value Driving Model of Network Marketing Environment

在线全文

学校读者我要写书评

暂无评论

Customer Value Driving Model of Network Marketing Environmen...

UNCERTAINTY ANALYSIS ON ZONATION MAPS OF DEBRISFLOW HAZARD IN YUNNAN PROVINCE,CHINA

2011 International Conference on Information Management and Engineering(ICIME 2011)

作者： WANG Ji-lin liu xi-lin School of Management Northwestern Polytechnical University

ISBN: (纸本)9781612842387

The paper summarizes the research status of customer value at home and abroad, and points out the existing research deficiencies. Combining network marketing its own characteristics, the customer value driving model of network marketing environment is constructed, and the structure relation and application of the model are explained.

关键词： customer value network marketing marketing driving model

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Chinese Geographical Science 2000年第2期10卷 138-143页

作者： liu xi-lin(Dapartment of Urban and Environmental Scicnces, Peking University Beijing 100871, P.R.China Institute of Moun tain Hazards and Environment, the Chinese Academy of Sicnces, Chengdu 610041,P.R.China) Department of Urban and Environmental Sciences Peking University Beijing P. R. China Institute of Mountain Hazards and Environment the Chinese Academy of Sciences Chengdu P. R. China

Different researchers select different factors and use different methods to assess the regional hazard degrees of debris now. consequenily, even for the same region, tb.. are often different hazard zonation maps, and there must be some uncertainty in the zonations. Thus the ceriainty analysis of zonation maps becomes obviously *** debris now hazard, those zonation maps with a certainty analysis could provide most valuable information for land users, hazard managers and policy makers. By comparison of three researchers’ findings in Yunnan Province, this paPer shows that seven to nine iafluential factors are chosen for the zonation maps. spatial density of debris flow ravines,regional average rock-weathering coefficient, yearly precipitation, days of≥50 mm daily rainfall, and proportion of sloping land with slope≥25℃to the total land are the most acceptable factors. Mathemahcal methods of maximum-minimumvalues, upperlower limit values and Fuzzy values are used to quantify the factors. Step-by-step methodoogy is commonly used for the zonation maps. Research results show that mchmum uncedrinty is 66. 6% and minimum uncertainty is 35.7% in debris now hazard maps of zhaotong Prefecture and Yunnan Province. Therefore there is still much work for us to improve the zonation methedology.

关键词： debris flow hazard zonation uncertainty zonation map

在线全文

学校读者我要写书评

暂无评论

多孔介质中流动泡沫的压力分布计算

化学工程 2009年第6期37卷 20-23,36页

作者：庞占喜刘慧卿刘喜林中国石油大学石油工程教育部重点实验室北京102249 中国石油辽河油田分公司博士后工作站辽宁盘锦124010

将多孔介质简化为一簇变截面毛细管组成的毛细管束,根据多孔介质的颗粒直径、颗粒排列方式、孔喉尺度比以及束缚水饱和度,计算出变截面毛细管的喉道半径和孔隙半径。在考虑多孔介质喉道和孔隙中单个气泡的受力和变形基础上,利用质量守... 详细信息

将多孔介质简化为一簇变截面毛细管组成的毛细管束,根据多孔介质的颗粒直径、颗粒排列方式、孔喉尺度比以及束缚水饱和度,计算出变截面毛细管的喉道半径和孔隙半径。在考虑多孔介质喉道和孔隙中单个气泡的受力和变形基础上,利用质量守恒定理和动量守恒定理,推导出单个孔隙单元内液相的压力分布和孔隙单元两端的压力差计算公式,最终得到多孔介质的压力分布以及多孔介质中泡沫当量直径计算方法。利用长U型填砂管对多孔介质中稳定泡沫的流动特性进行了实验研究,并对实验结果和计算结果进行了对比。结果表明:稳定泡沫流动时多孔介质中的压力分布呈线性下降,孔喉结构和泡沫干度是影响泡沫封堵能力的主要因素;泡沫的封堵能力随泡沫干度的增加而先增加后降低,在泡沫干度为85%时达到最强封堵能力。

关键词：泡沫多孔介质变截面毛细管稳定流动压力分布

自然灾害发生时间序列的分形特征及R/S分析

在线全文

学校读者我要写书评

暂无评论

自然灾害学报 2005年第6期14卷 37-41页

作者：倪化勇刘希林中国科学院成都山地灾害与环境研究所

统计了公元960年到1979年我国地震、洪涝和台风风暴潮灾害发生的时间及死亡人数,以分形几何中的Cantor集合为模型,发现我国自然灾害发生时间序列的分布呈现出明显的分形特征,并采用Sm alley方法分别计算了不同灾害发生时间序列分布的分... 详细信息

统计了公元960年到1979年我国地震、洪涝和台风风暴潮灾害发生的时间及死亡人数,以分形几何中的Cantor集合为模型,发现我国自然灾害发生时间序列的分布呈现出明显的分形特征,并采用Sm alley方法分别计算了不同灾害发生时间序列分布的分维值,它们均在0.5左右,同严格意义上的数学分形Cantor集合相比分维较小,说明我国地震等自然灾害发生发展的自组织程度还有进一步发展的趋势,其危害程度将可能进一步提高;在自然灾害发生时间序列的分形特征的基础上,通过R/S分析,得出3种自然灾害发生时间序列的H指数均在0.28左右,同日斑指数、树木年轮、湖泊水位变化等自然现象相比较小,说明自然灾害的发生具有短程相关性,其发生规律没有日斑指数等自然现象明显。该研究对于进一步认识和研究我国地震等自然灾害的发生规律和发展趋势等具有一定意义。

关键词：自然灾害时间序列分维 Cantor集合 R/S分析