Results 81 to 90 of about 13,853 (179)
Microscopic fracture characterization and permeability evolutionary patterns of granites under cyclic thermal shock [PDF]
ObjectiveThis study aims to reveal the microscopic damage characteristics and permeability evolutionary patterns of high-temperature granite reservoirs fractured under cyclic thermal shock produced by low-temperature fluids like drilling fluids and ...
Chengcheng REN +5 more
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Shuitu Baochi Xuebao, 2011 运用分形模型研究了重庆四面山几种林地土壤颗粒的分形特征,并探讨了分形维数与粒级分布的关系及其影响因素。结果表明:①0-60cm土壤分形维数平均值的顺序为:针叶林>针阔混交林>楠竹林>阔叶林,阔叶林和楠竹林土壤具有相对疏松、通透性好的结构,而针叶林和混交林地土壤质地较细,具有较好的持水保肥性能。②随着土层深度的增加,阔叶林地土壤的分形维数减小最为显著,楠竹林地呈增大的趋势,而针叶林和针阔混交林地减小不显著。这种变化与4个剖面上粘粒含量的变化规律完全一致。③分形维数能够表征土壤颗粒的大小和数量 ...
王贤 +6 more
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Zhejiang Daxue xuebao. Lixue ban, 2019 介绍了Husimi 分布函数的基本特性及其引入过程和非对易（相） 空间中物理量及物理规律的表述方法。把普通对易空间中的一维相干态辐射场的Husimi 分布函数推广到三维形式，利用Bopp 变换，得到了非对易相空间中的三维相干态辐射场的Husimi 分布函数，并用对易空间中的参数对其进行了描述。
WANGXingzhong(王兴忠)
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Effect of Supercritical Carbon Dioxide (SCCO2) on the mechanism of change in pore and fracture structure of coal with different moisture content [PDF]
When the CO2 in a supercritical state (SCCO2) is released from deep coal seams, it reacts with minerals in coal, changing the porosity of coal, which in turn affects the effect of CO2 sequestration in coal seams and the effect of increasing methane ...
Lei HAN +4 more
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Shuitu Baochi Xuebao, 2011 土壤粒径分布影响土壤的水力特性、土壤肥力以及土壤侵蚀状况等,是重要土壤物理性状之一。以黄河三角洲滩地土壤为研究对象,利用单重与多重分形学理论和方法,对黄河三角洲滩地不同土地利用方式土壤的分形特征及其与土壤有机质的相关性进行研究。结果表明,不同土地利用方式对土壤单重分形维数D有显著影响,D值介于2.465 7～2.678 9,其中,林地的D值最大,粘粒含量最高,砂粒含量最低;而荒草地的D值最小,粘粒含量最低,砂粒含量最高;土壤粒径分布的多重分形参数D0(容量维数)、D1(信息维数)和D1/D0(信息维数 ...
吕圣桥 +4 more
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Shuitu Baochi Xuebao, 2021 柽柳（Tamarix chinensis）沙包是古尔班通古特沙漠地区特殊的生物地貌景观，对维持区域生态环境稳定具有重要作用。采用野外调查与室内分析相结合的方法，对古尔班通古特沙漠西南缘柽柳沙包0—500 cm层土壤粒度特征进行分析。结果表明：（1）该地区柽柳沙包土壤粒度组成以细粒物质为主，其中粉粒含量最高，其次为极细沙粒，两者含量达到80%以上，且50 μm以下土壤粒度含量在57%以上。（2）随着土层深度的增加，黏粒、粉粒、平均粒径及分形维数总体呈先升高后降低再升高的变化趋势，极细沙粒 ...
董正武 +3 more
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Influence of the position and depth of pre-cutting kerfs on the rock breaking by SBM cutter [PDF]
The combination of water-jet and disc-cutter rock breaking is a key technology to improve the rock breaking efficiency of the full-face shaft boring machine and achieve the mechanized development of deep resources.
Chenxi DING +5 more
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Shuitu Baochi Xuebao, 2008 探讨干旱缺水地区灌溉方式对果园土壤物理性质的影响,为采取合理的果园节水灌溉措施、有效利用灌溉水资源提供科学依据。以鲁中南山地果园为研究区域,利用分形理论,对渗灌和漫灌条件下果园土壤物理性质及其分形特征进行了研究。结果表明:(1)渗灌和漫灌土壤物理性质存在着明显的异质性,二者差异显著,土壤容重渗灌比漫灌降低6.71%;土壤总孔隙度、非毛管孔隙度和毛管孔隙度渗灌比漫灌分别高11.62%,43.84%和8.72%。(2)渗灌和漫灌土壤粒径分布存在明显差异,土壤的粘粒和粉粒含量渗灌高于漫灌 ...
高鹏 +4 more
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Research on the evolution and prediction of the heights of water-conducting fracture zones in overlying rocks during layered mining of extremely thick coal seams [PDF]
Current research on the developing heights of water-conducting fracture zones mainly focuses on the heights of water-conducting fracture zones in single coal seam mining, while research on the prediction of the developing heights of water-conducting ...
CHENG Xianggang, MENG Hailun, QIAO Wei
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Transient signal feature extraction based on box dimension and maximum Lyapunov dimension [PDF]
, 2013 认知无线电是一种通过无线频谱感知来有效提高频谱利用率的无线通信技术。它除了面临传统无线通信的各种安全问题外,还会面临一些新的问题,比如模仿主用户攻击(PuE)。提出基于分形维数的瞬态信号特征提取来预防认知无线网络中的模仿主用户攻击,并通过实验提取无线发射机的分形维数,为下一步信号识别提供可靠的特征参数,达到预防PuE攻击的目的。Cognitive radio is one kind of wireless communication technology,which effectively ...
赵彩丹, 颜富甲, 黄联芬
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