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Search Results: 1 - 10 of 457039 matches for " <br>张勃 "
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Zhang Bofu,<br>
自然资源学报 , 1990,
Abstract: The complex geological structure, the frequent activities of volcanos, and the strong neo-tectonic movement are the favourable conditions for the natural mineral spring water to form and emerge. The basic characteristics of the carbonated mineral spring water in the Chang-Bai Mountains are: the contents of CO2, and H2SiO3 are very large, the mineralization degree is very high, and it is rich in some trace elements such as Sr, Li, Zn, ect. The majority of the silicic acid mineral spring water contain Srand some contain Zn.The natural mineral spring water is widely distributed in Jilin Province. Its exploitation has many advangeous conditions such as rich resources, concentrated distrution, and the excellent quality of the water. The basic strategy for exploiting the mineral spring water includes overall planing, protecting resources, making rational exploitation, increasing advertisement, etc.The recent activities of volcanos and the active faults are the two mechanisms to form the mineral spring water. So volcano groups and active fault belts in the province are the most hopeful locations to find the mineral spring water.
Review on Land Use and Land Cover Change Models

ZHANG Hu,ZHANG Bo,<br>张华,
自然资源学报 , 2005,
Abstract: Land Use and Land Cover Change (LUCC) study has been carried out for a long time in the world.Recently,because of contribution and response of LUCC to global change,it is necessary to predict LUCC.Therefore,more and more scientist s devote themselves to studying LUCC models,and have made positive progress in t his aspect.This paper presents some correlative issues about LUCC models,i.e.,sc ale dependency of LUCC modeling,data issues of LUCC modeling,and location and qu antity of land,use change prediction.It reviews the available five kinds of main LUCC models:1)Agent,based Models of Land,use/Land,cover Change(ABM/LUCC);2)Empi rical statistical models;3)Optimisation Model;4)Hybrid/Integrated models;and 5)D ynamic simulation models.It then summarizes the problems of the existing models, and discusses the future developing direction of LUCC models.Although much progr ess has been made in theory and practice of LUCC models,and many new modeling me thodology and technique have been developed with multiple purposes,there still e xist certain problems in these models.The understanding of LUCC models multi,sca le attribute is inadequate and there is a lack of interaction of the temporal an d spatial studies of the models,so the validity of the models is affected.Finall y,we should further strength the integration of modeling methodology and constit ute more effective LUCC models.
The Study on Affecting Factors of Runoff Changes at Yingluoxia Station of Heihe River

YANG Mingjin,ZHANG Bo,<br>杨明金,
地理科学进展 , 2010,
Abstract: Based on the runoff data covering 45 years at Yingluoxia Station at the main stream of the Heihe River,this paper studied the global change,sunspot activity,ENSO cycle and underlying surface variation affecting the change of mountainous runoff at the main stream of the Heihe River using correlation analysis,cross-spectrum analysis,statistical law analysis and precipitation-runoff double mass analysis. The results showed that:(1) The global change had significant influence on the runoff of Yingluoxia Station...
Characteristics of Frost Days and Accumulated Temperature in Eastern Gansu Over the Last 40 Years

WANG Yuanyuan,ZHANG Bo,<br>王媛媛,
资源科学 , 2012,
Abstract: 本文基于陇东地区15个气象站点1971年-2010年的逐日气温和地温资料,采用相关分析、气候倾向率、MK突变检验法,结合GIS空间分析技术,对各站逐年的初、终霜日、无霜期及≥0℃、≥10℃和<0℃积温与持续日数等进行定量化分析,并阐述其时空变化特征及相互关系。结果表明:陇东地区初霜日和无霜期分别与纬度和海拔呈负相关,与经度呈正相关,终霜日则与纬度和海拔呈正相关,与经度呈负相关;20世纪70年代和80年代初霜日偏早,终霜日偏晚,无霜期较短,自90年代以来呈反向变化;大部分地区初霜日后推,终霜日提前,无霜期延长,主要集中在中南部的镇原、崇信等地;初霜日和无霜期的突变年分别在1986年、1987年和1984年,终霜日无明显突变年。本区积温呈显著上升趋势,积温年均最大值与年均最晚初霜日、最早终霜日和最长无霜期都位于陇东南部地区;积温年均最小值与年均最早初霜日、最晚终霜日和最短无霜期则分布于西部和北部地区。

中国沙漠 , 1993,
Abstract: 绿洲农业是在荒漠环境下人为控制的生态系统,具有生态结构简单、生态系统脆弱、稳定性差等特点。本文运用系统论、耗散结构理论及生态学的基本原理,对酒泉绿洲农业生态系统的结构和功能进行了分析,提出了以水定地,解决水土平衡问题,促使水盐动态的协调。制定了合理的灌溉定额及其保护和发展林草植被的调控措施。
Space-Time Coupling Analysis of Climate Change and Runoff in Hexi Inland Arid Region:A Case Study of Heihe River Valley in the Middle Region of Hexi Corridor

LIU Jing-feng,ZHANG Bo,<br>柳景峰,
资源科学 , 2008,
Abstract: 基于ArcGIS平台的地统计Kriging插值方法,分析了黑河上中游25个气象和水文站点1956年~2000年逐月气温、降水、蒸发和径流资料,并且空间化显示了各年代间的气温、降水和蒸发的变化幅度,结果表明:本区域气温和降水的变化及由此引起的蒸发和径流的变化具有时间和空间上的差异性,反映了大气环流、地形、下垫面因素和径流变化的时空耦合性。60年代~70年代开始整体升温, 70年代以来80年代和90年代气温上升最为典型,高山湿润半湿润区气温升高约为0.5℃~0.6℃,平原荒漠区升温一般高于0.5℃,同期中西部山区降水增加, 50年代~60年代之间西北部降水增加、中部小幅减少, 60年代~70年代上中游绝大部分地方的降水增加,70年代~80年代除北山迎风坡降水增加较少外,其它地方降水均增加较多,80年代~90年代降水的变率呈现出由西向东规律性递减的趋势。另外,径流形成主要受到山区降水的影响,但冬季气温的上升会将融雪期提前,增加冬季流量,影响流域的春季径流。上游降水量和径流增幅比较接近,体现出时间上的一致性和空间上的拟合性,径流和降水的变化系数分别为1.3444和1.4823。平原大面积的人工绿洲区升温幅度较低,在0.3℃~0.5℃,与局地下垫面即绿洲的小气候效应有关。
冰川冻土 , 2002,
Abstract: 对干旱区绿洲的物质和能量空间分异现象和规律的研究,有助于深刻了解不同类型绿洲形成和演化的自然背景和农业资源组合的特点,为农业生产的合理布局和农业自然资源的优化配置提供理论依据.以黑河流域绿洲为例,在综合分析影响绿洲空间分异的气候、地质构造和地貌演化、地表水和地下水水文化学性质、土壤性状和水资源供应状况等自然地理要素基础上,将黑河绿洲划分为高位绿洲、中位绿洲和低位绿洲等不同类型.在此基础上,分析了黑河流域不同类型绿洲主要农作物气候适宜性的空间分异,为绿洲农业资源的优化配置提供了重要的理论依据。
An approach to the designing principle of desertification indicators

SUN wu,NAN Ahong ren,LI Bao sheng,ZHAN Bo,<br>孙武,南忠仁,李保生,
自然资源学报 , 2000,
Abstract: Desertification index system plays an important role in desertification research,as indicating both the level of dynamic mechanism of desertification and the contribution to the rehabilitaition of desertified land.Firstly,the problems concerning the selection,acquisition,quantification and checking about index are evaluated according to the criterion of standardization,simplicity and practicability.Then,the approach is made to the relationship between ecological base plane and indicators.Finally,based on the view that the establishment of ecological base plane is fundamental to ideal index system in the desertification monitoring and assessment,three principles to design index system are put foreward,which are respectively zonation,scale and landscape.
Cross-layer feedback based adaptive coding for wireless video transmission

Wang Yaozhong,Zheng Shibao,Zhang Chongyang,Liu Bo,<br>王垚中,郑世宝,重阳,
中国图象图形学报 , 2012,
Abstract: One cross-layer feedback based on video coding scheme is proposed in this paper,which applies both adaptive modulation coding(AMC)and automatic repeat request(ARQ)techniques to provide an adaptive wireless video coding solution.Within this method,timely channel-aware can be obtained by the feedback information from the PHY layer,and then the video encoder at application(APP)layer can take accurate rate control to adapt the channel’s bandwidth varying.Experimental results showed that,compared to the existed scheme without feedback and channel-aware,the proposed method can get a significant improvement in Peak Signal-to-Noise Ratio(PSNR)for wireless video transmission.
The Study on the Change of Mountainous Runoff in Heihe River Basin from 1950 to 2004

YANG Mingjin,ZHANG Bo,WANG Haiqing,YUAN Jianping,<br>杨明金,,王海青,袁健萍
资源科学 , 2009,
Abstract: 以黑河流域出山口莺落峡水文监测站1950年~2004年55 年的天然径流序列为基础数据,径流年际变化规律采用滑动平均、累积距平曲线、Mann-kendall非参数统计检验等方法指标,径流年内分配变化规律采用分配不均匀系数、集中度(期)及变化幅度等方法指标,定性与定量相结合,分析黑河流域出山径流年际年内变化规律。结果表明:①莺落峡多年径流量呈现增加的趋势,但是趋势不是很显著。1959年和1979年是莺落峡径流量突变开始的年份,1959年是莺落峡径流量由多变少的突变年份,1979年是莺落峡径流量由少变多的突变年份。累积距平曲线和Mann-kendall突变检验同时验证了这一结论;②受径流补给条件(大气降水)的影响,莺落峡径流年内分配主要集中在汛期,即5月~10月,其径流量占全年平均径流量百分比都超过80%,11月~次年4月所占比重不大;③不均匀性和集中程度1950s最大,2000s最小,其它各年代介于二者之间,但差别不大。集中期最大径流量1970s和2000s出现时间较多年平均的7月30日推迟6~7天,其它各年代出现时间比较接近,前后仅相差一两天,相对变化幅度呈现减小的趋势,绝对变化幅度表现出节律性变化规律;④集中度RCD有比不均匀系数Cv为大的变幅和分辨力,能更充分地反映径流年内分配的特点,用集中度RCD表示径流年内分配更为合适。
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