铜川市滑坡侵蚀灾害强度分区研究

铜川市是滑坡侵蚀灾害严重的地区之一,本项研究调查了铜川市滑坡侵蚀的形成环境,分析了滑坡侵蚀的基本规律,用现场调查得到的滑坡侵蚀量作等值线图,按照等值线将铜川市滑坡侵蚀强度分为剧烈侵蚀区、强烈侵蚀区、中度侵蚀区、轻度侵蚀区、微弱侵蚀区5个等级的分区。结果表明,中等以上侵蚀区面积5 8.2 5km2,占研究区总面积的70.6%。研究区内共有滑坡12 7个,滑坡侵蚀量115 42.6万t,占重力侵蚀总量的92.9%。研究表明,铜川市滑坡侵蚀非常剧烈,必须尽快建立防灾、减灾的预警系统,加大治理对人们生命财产有威胁的滑坡侵蚀。      

沙层特性对沙盖黄土坡面产流产沙变化贡献的定量分析

沙盖黄土坡面产流产沙方式独特,侵蚀过程复杂,量化降雨过程中该类坡面产流产沙变化影响因素贡献的大小对揭示其侵蚀机理具有重要的意义。基于室内模拟降雨试验,定量分析沙层厚度（2 cm、5 cm和10 cm）和粒径组成（100%粒径≤ 0.25 mm、75%粒径≤ 0.25 mm +25%粒径> 0.25 mm、50%粒径≤ 0.25 mm+50%粒径> 0.25 mm、未处理原沙和100%粒径> 0.25 mm）在降雨过程中对产流产沙变化的影响和贡献。结果显示：沙层厚度增加能明显延长产流时间,减少总产流量,增加总产沙量,增大降雨过程中产流产沙的变异性;随沙层粒径组成变粗,初始产流时间和产沙量无明显变化规律,产流量有增大趋势。沙层厚度、粒径组成及二者交互作用对初始产流时间变化的贡献率分别为68.03%、15.77%和3.85%。沙层厚度对降雨不同时段15 min产流量和不同历时总产流量的贡献率分别在23.89%~52.22%和41.10%~48.94%之间,对相应产沙的贡献率分别在29.19%~62.01%和13.53%~30.31%之间。整体上沙层粒径组成变化对产流产沙量变化的贡献率小于沙层厚度,且无明显规律。沙层厚度和粒径组成交互作用对产流量和降雨中前期产沙量的影响显著（p < 0.05）,其对产流产沙变化的贡献率分别在13.12%~26.62%和3.22%~43.12%之间,不同降雨时段变化明显。研究结果说明,沙层厚度决定沙盖黄土坡面产流产沙过程,其和沙层粒径组成对产流产沙的影响和贡献随坡面沙层的侵蚀演化而动态变化,且二者的交互作用也不容忽视。     

SNMP与NetStream流量监控方法的对比分析

随着海洋信息通信网业务需求量的日益增加,以及用户对网络性能要求的提高,网络管理必不可少,而流量监控和统计分析是网络管理的基础.本文主要对海洋信息通信网中不同的流量监控技术进行研究,通过分析海洋信息通信网网络监控现状、SNMP流量监控技术、NetStream流量监控技术以及通过对比对两种监控手段在海洋信息通信网中的差异,找到适合海洋信息通信网的流量采集手段.     

梯田建设和淤地坝淤积对土壤侵蚀影响的定量分析(英文)

To study the influences of terraced field construction and check-dam siltation on soil erosion of a watershed,we built a simplified watershed model for the Loess Plateau hilly-gully region including terraced fields,slope farmlands,steep-slope grasslands,and dam farmlands,and defined three states of watershed(i.e.,pioneer,intermediate,and climax stages,respectively).Then,the watershed soil erosion moduli at various stages were studied by using a revised universal soil loss equation.Our results show that the pioneer and climax stages are the extreme states of watershed soil-and-water conservation and control;in the pioneer stage,the soil erosion modulus was 299.56 t ha-1 a-1 above the edge of gully,136.64 t ha-1 a-1 below the edge of gully,and 229.74 t ha-1 a-1 on average;in the climax stage,the soil erosion modulus was 39.10 t ha-1 a-1 above the edge of gully,1.10 t ha-1 a-1 below the edge of gully,and 22.81 t ha-1 a-1 on average;in the intermediate stage,the soil erosion modulus above the edge of gully exhibited an exponential decline along with the increase in terraced field area percentage,while the soil erosion modulus below the edge of gully exhibited a linear decline along with the increase in siltation height.     

不同植被类型的坡面径流侵蚀产沙试验研究

利用野外模拟降雨试验,研究不同植被类型的侵蚀产沙、径流、地表糙度和入渗规律以及相关关系。结果表明,植被对水沙调控作用大小依次为:植物根系,整个坡面植被,坡面下部植被和坡面上部植被。林草地具有蓄水减沙的水土保持措施功效,该机制通过植物根系对水沙的调控作用实现;草地具有直接拦沙的水土保持功效,该机制通过地表植被对水沙的调控作用体现。累计产沙量随累计径流量呈幂函数递增趋势,具有很好的相关性;坡面径流产沙过程分为发育期、活跃期和稳定期3个阶段。植被覆盖度越大,地表糙度变化越小。     

Numerical simulation of wave field in the South China Sea using WAVEWATCH III

Wave fi elds of the South China Sea(SCS) from 1976 to 2005 were simulated using WAVEWATCH III by inputting high-resolution reanalysis wind fi eld datasets assimilated from several meteorological data sources. Comparisons of wave heights between WAVEWATCH III and TOPEX/Poseidon altimeter and buoy data show a good agreement. Our results show seasonal variation of wave direction as follows: 1. During the summer monsoon(April–September), waves from south occur from April through September in the southern SCS region, which prevail taking about 40% of the time; 2. During the winter monsoon(December–March), waves from northeast prevail throughout the SCS for 56% of the period; 3. The dominant wave direction in SCS is NE. The seasonal variation of wave height H s in SCS shows that in spring, H s ≥1 m in the central SCS region and is less than 1 m in other areas. In summer, H s is higher than in spring. During September–November, infl uenced by tropical cyclones, H s is mostly higher than 1 m. East of Hainan Island, H s 2 m. In winter, H s reaches its maximum value infl uenced by the north-east monsoon, and heights over 2 m are found over a large part of SCS. Finally, we calculated the extreme wave parameters in SCS and found that the extreme wind speed and wave height for the 100-year return period for SCS peaked at 45 m/s and 19 m, respectively, SE of Hainan Island and decreased from north to south.     

陕北黄土高原可持续发展评价研究

通过对陕北黄土高原可持续发展评价指标体系和方法的初步研究,设计出了包括 1个高级综合指标——可持续发展综合指数、人口状况等 5个基本指标和人口自然增长率等 30个元素指标的层次性指标体系结构框架,熵技术支持下确定可持续发展指标权重的层次分析法,以及由递阶多层次综合评价、主成份分析和回归分析等数学方法所集成的可持续发展全面综合评价模型,并依次对该地区可持续发展现状及趋势进行了全面分析评价。     

神府东胜煤田开发中人为泥石流发育现状及其分布特征

神府东胜煤田我国本世纪重要能源供应地，90年代大规模开发以来泥石流频繁发生，通过实地考察发现：神府东胜煤田泥石流规模小、同人为诱发的人为泥石流，泥石流的分布特征与人工采石场等弃土弃堆放地的分布紧密对应；泥石流呈集群式分布，与地面物质组成密切相关；泥石流主要分布在面积为1km^2以下的二级沟里。     

坡面侵蚀水沙流时间变化特征的模拟实验

多坡段实验模型以黄土丘陵沟壑区垂向上梁峁坡面与沟谷坡面构成的坡沟系统为原型,采用人工降雨模拟实验方法,对坡沟系统土壤侵蚀链内降雨径流产沙随时间变化的规律进行了系统的研究。结果表明:雨强29 7mm/h时36′40″开始产流,60 5mm/h时3′43″产流,90 2mm/h时2′30″产流。雨强29 7mm/h时侵蚀过程以面蚀为主,产沙起伏20min出现一次。60 5mm/h时以面蚀与细沟蚀为主,35°陡坡伴有崩塌、滑塌等重力侵蚀,产沙波动平均12min出现一次。雨强90 2mm/h时坡面上细沟发育充分,有细沟合并及出现浅沟侵蚀现象,35°坡崩塌、滑塌剧烈,产沙过程波动频繁,每10min一次。雨强29 7mm/h时单位流量的产沙量为0 10kg/L;雨强60 5mm/h时为0 30kg/L;雨强90 2mm/h时为0 41kg/L。流量的大小影响了侵蚀方式和形态分异的程度,使产沙过程出现强弱相间的波动性特点。