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91.
Yu Chongwen Faculty of Earth Sciences China University of Geosciences Wuhan 《中国地质大学学报(英文版)》1998,9(1)
QUANTITATIVEDYNAMICSTRATIGRAPHY(QDS)Duringthepastfewdecadesindependentstudiesofsedi-mentarybasinswerecarriedoutalongdiferenta... 相似文献
92.
层析成像的分辨率取决于对地震(声波)全波列记录信息提取的精度,本文阐述了从地震(声波)全波列记录提取特征信息,建立三层神经元网络模型,利用神经元网络对地震(声波)全波列记录的信息提取,如初至波走时拾取。本文讨论了神经元网络模型的建立和神经元网络模型的学习。侧重讨论了初至波出现时的特征并对它进行了定量化描述,用它对地震(声波)全波列记录信息提取,取得了很高的精度。 相似文献
93.
黄培之 《武汉大学学报(信息科学版)》1989,(4)
本文对利用以规则格网表示的地面数字高程模型绘制透视立体图的方法进行了讨论,以透视原理为基础计算出模型点对应的变换点坐标。在分析过去采用的单方向处理隐藏线的方法基础上,提出了双方向处理隐藏线的方法,并应用该方法绘制出了透视立体图。 相似文献
94.
In order to obtain a better understanding of the behavior of aerosols and SO2 in the longrange transport through a marine boundary layer, a simple box-model is applied to the evaluation of the residence times of the species from the concentrations of gases and aerosols measured simulataneously on two islands in the West Pacific Ocean in the north-west monsoon. For Aitken and large particles, the residence time is varied from 3.7 to 7.4 days depending on the particle size, and their flux to the sea is equal to or slightly smaller than that of the free atmosphere. The residence time of giant particles is about one day and their flux to the sea is three times larger than that of the free atmosphere. The residence time of SO2 is 15 hr, and the relative SO2 mass flows of the deposition to the sea, of the diffusion to the free atmosphere and of the transformation to SO4
2- are approximately 4, 1 and 1, respectively. 相似文献
95.
96.
概述了乐山建材非金属矿产资源的主要特征,阐明了其勘查与开发利用现状,并对资源形势作了分析,进而论述勘查与开发利用的前景。 相似文献
97.
位于北方农牧交错区地形、气候、植被过渡带的宁夏盐池县是典型的农牧生产和生态敏感区。基于农户视角,应用目标-过程-结果-调控四维分析框架(TPOA)和问卷数据,分析禁牧政策的实施效果和适时调整问题,对于全面了解禁牧政策的实施效用、制定相应的调控对策具有一定的实践指导意义,可为北方农牧交错区禁牧的适时调整与草原的合理利用提供案例支撑。禁牧政策实施中,60.40%、55.38%和11.83%的受访户分别采取了扩张型、调整型和收缩型适应策略,农户从事非农产业的比例提高,夜间偷牧现象普遍,存在饲草缺口大、养殖成本高、龙头企业带动力不强、市场监管难等困境。该政策的实施实现了盐池当地草原生态恢复和沙漠化逆转,38.79%的受访户认为禁牧政策确实“达到了”生态恢复的预期目标,60.87%的农户对草原补奖表示满意,46.09%的受访户认为禁牧政策亟待调整,可从提高禁牧补偿标准、生态适宜地区适当开牧、延长补助期限等方面着手。将TPOA框架应用于禁牧政策效果评价中,为评价生态政策的实施绩效提供了理论基础。 相似文献
98.
延边东部金铜矿化区成矿规律与找矿方向 总被引:2,自引:1,他引:1
珲春东北部金铜矿化区与古生代、中古生代火山岩浆活动有关。通过对中生代火山岩及矿区地质特征,构造控矿特征及已知典型矿床的研究,提取多元综合成矿信息,总结出矿化区控岩、控矿条件及找矿标志,确定了区内找矿靶区和找矿方向,并对成矿远景进行了评价。 相似文献
99.
Air temperature(AT) is a subsystem of a complex climate.Long-range correlation(LRC) is an important feature of complexity.Our research attempt to evaluate AT’s complexity differences in different land-use types in the Heihe River Basin(HRB) based on the stability and LRC.The results show the following:(1) AT’s stability presents differences in different land-use types.In agricultural land,there is no obvious variation in the trend throughout the year.Whereas in a desert,the variation in the trend is obvious: the AT is more stable in summer than it is in winter,with Ta ranges of [8,20]°C and SD of the AT residual ranges of [0.2,0.7],respectively.Additionally,in mountainous areas,when the altitude is beyond a certain value,AT’s stability changes.(2) AT’s LRC presents differences in different land-use types.In agricultural land,the long-range correlation of AT is the most persistent throughout the year,showing the smallest difference between summer and winter,with the Hs range of [0.8,1].Vegetation could be an important factor.In a desert,the long-range correlation of AT is less persistent,showing the greatest difference between summer and winter,with the Hs range of [0.54,0.96].Solar insolation could be a dominant factor.In an alpine meadow,the long-range correlation of AT is the least persistent throughout the year,presenting a smaller difference between summer and winter,with the Hs range of [0.6,0.85].Altitude could be an important factor.(3) Usually,LRC is a combination of the Ta and SD of the AT residuals.A larger Ta and smaller SD of the AT residual would be conducive to a more persistent LRC,whereas a smaller Ta and larger SD of the AT residual would limit the persistence of LRC.A larger Ta and SD of the AT residual would create persistence to a degree between those of the first two cases,as would a smaller Ta and SD of the AT residual.In addition,the last two cases might show the same LRC. 相似文献
100.
Analyses of the soil moisture evolution trend and the influence of different types of radiation on soil moisture are of great significance to the simulation and prediction of soil moisture.In this paper,soil moisture(2–60 cm) and various radiation data from 2014–2015 at the A’rou superstation were selected.The radiation data include the net radiation(NR),shortwave and longwave radiation(SR and LR).Using adaptive fractal analysis(AFA),the long-range correlation(LRC) of soil moisture and long-range cross correlation(LRCC) between moisture and three types of radiation were analyzed at different timescales and soil depths.The results show that:(1) Persistence of soil moisture and consistency between soil moisture and radiation mutate at 18-d and 6-d timescales,respectively.The timescale variation of soil moisture persistence is mainly related to the influence process of radiation on soil moisture;(2) Both the soil moisture persistence and soil moisture-radiation consistency vary substantially with soil depth.The soil depth variation of soil moisture persistence is related to the influence intensity of radiation;(3) From 2–6 day timescales,LR displays the strongest influence on soil moisture at depths of 2–10 cm through negative feedback of radiation on the soil temperature.The influence intensity decreases with depth from 2–15 cm.Therefore,the soil moisture persistence is weak and increases with depth from 2–15 cm;and(4) At more than 6 day timescales,SR and NR display a stronger influence on the soil moisture persistence at depths of 2–40 cm through positive feedback of radiation on the soil temperature,especially at depths of 2–10 cm.This influence also weakens with depth.The soil moisture persistence at depths of 2–10 cm is the weakest and increases with depth from 2–40 cm.The research results are instructive for determining timescales and soil depths related to soil water in hydrological models. 相似文献