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148篇 您的检索式:作者名="Hesp"
    题名 作者 年代 出处 被引量
1海岸横向沙脊表面风沙流结构的野外观测研究显示文摘选择中国规模最大、形态最为典型的河北昌黎黄金海岸的横向沙脊,采用野外梯度风速仪和平口式积沙仪对其顶部的风沙流结构进行了观测。观测结果表明,海岸横向沙脊表面的风沙流结构特征基本表现为0~40cm高程内气流搬运的沙尘物质浓度或质量随高度递减并符合指数分布,20~60cm高程内符合幂函数分布,40~60cm高程内输沙量与高度之间则为多项式函数关系。同时,海岸横向沙脊表面的风沙流结构受风速与总输沙量的影响较大,随风速增大或总输沙量的增加,风沙流下层输沙量相对减少、上层则相应增加。董玉祥 P A Hesp S L Namikas 马骏 2008地理科学2008,28,4:29
2海岸横向沙脊表面风沙流结构粒度响应的野外观测研究显示文摘风沙流中沙粒粒度组成的垂向变化及不同粒径沙粒的垂向分布特征等是风沙流结构粒度响应的基本研究内容,但一直较缺少野外观测实证证据。在我国海岸沙丘集中分布的河北昌黎黄金海岸,选择规模高大、形态典型的横向沙脊,采用野外梯度风速仪和平口式积沙仪对其顶部风沙流结构的粒度响应进行了野外实地观测。结果表明,海岸沙丘表面风力的分选作用明显,与横向沙脊表面相比风沙流所含沙物质中细沙组分比例增多、粗沙组分比例降低;粒度构成的垂向变化是,在风沙流0—10 cm、10—40 cm和40—60 cm三个高程段内,分别是以中沙为主、中沙与细沙并重和以中沙为主,其中中沙含量在三个高程段内分别呈现出自地表向上逐渐降低、含量比较稳定、向上逐渐升高的垂向变化,细沙则呈现相应的反向变化,随之平均粒径也呈现为自下而上逐步变细、比较稳定到逐渐变粗的变化,但分选系数、偏度和峰态无明显差异;横向沙脊顶部的风沙流结构整体符合指数分布,但不同粒径沙粒的垂向分布特征并不相同,其中粗沙为幂函数分布,细沙遵循指数函数递减,中沙的指数函数和幂函数拟合均有较高相关系数,但在0—40 cm高度内更符合指数函数分布。董玉祥 Hesp P A Namikas S L 马骏 2008中国沙漠2008,28,6:21
3海岸风沙流中不同粒径组沙粒的垂向分布模式显示文摘通过对河北昌黎黄金海岸沙丘风沙流的野外实地观测与室内风洞模拟实验数据的数值模拟,探讨了我国典型海岸沙丘风沙流中不同粒径组沙粒输沙量的垂向分布模式。结果表明,河北昌黎黄金海岸沙丘表面风沙流中不同粒径组沙粒输沙量的垂向分布特征并不一致,其中细沙和中沙符合典型的指数递减分布规律,但粗沙则为负幂函数分布。究其原因,主要与不同粒径组沙粒输沙量的分布高度及运动方式差异有关。在实际非均匀沙床面上,粗沙主要集中分布于沙丘表面4cm高度内湍流发育的近地表层,运动方式以蠕移为主,沙丘表面湍流的主导作用使其输沙量随高度的变化满足负幂律关系,但中沙和细沙则以跃移运动为主,跃移沙粒输沙量的垂向分布呈现指数递减特征。董玉祥 S. L. Namikas P. A. Hesp 2009地理研究2009,28,5:14
4Field Measurements of Influence of Sand Transport Rate on Structure of Wind-sand Flow over Coastal Transverse Ridge显示文摘The structure of wind-sand flow under different total sand transport rates was measured with field vertical anemometer and sand trap on the crest of typical coastal transverse ridge in Changli Gold Coast of Hebei Province, which is one of the most typical coastal aeolian distribution regions in China and famous for the tall and typical coastal transverse ridges. The measurement results show that, on the conditions of approximate wind velocities and same surface materials and environments, some changes happen to the structure of wind-sand flow with the increase of total sand transport rate on the crest of coastal transverse ridge. First, the sand transport rates of layers at different heights in the wind-sand flow increase, with the maximum increase at the height layer of 4-8cm. Second, the ratios of sand trans-port rates of layers at different heights to total sand transport rate decrease at the low height layer (0-4cm), but increase at the high height layer (4-60cm). Third, the distribution of the sand transport rate in the wind-sand flow can be expressed by an exponential function at the height layer of 0-40cm, but it changes from power function model to ex-ponential function model in the whole height layer (0-60cm) and changes into polynomial function model at the height layer of 40-60cm with the increase of total sand transport rate. Those changes have a close relationship with the limit of sand grain size of wind flow transporting and composition of sand grain size in the wind-sand flow.DONG Yuxiang S L NAMIKAS P A HESP MA Jun 2008Chinese Geographical Science2008,18,3:9
5沥青胶结料低温物理硬化及结晶动力学分析显示文摘为了准确模拟沥青胶结料的物理硬化过程及评估其物理硬化趋势,采用常规弯曲梁流变(BBR)试验设备对10种常用道路沥青进行了改进弯曲梁流变(EBBR)试验,并根据试验结果计算了低温等级损失指标;此外,在设计不同的低温恒温养护时间的基础上,测试了沥青蠕变劲度与蠕变劲度变化率,并采用Avrami等温结晶动力学理论对试验结果进行了拟合分析.结果表明:EBBR法较BBR法对沥青的低温性能区分精度更高;采用Avrami等温结晶动力学理论可较好地模拟沥青胶结料的物理硬化过程,拟合分析得到的Avrami指数与EBBR试验得到的低温等级损失值变化规律具有一致性;沥青胶结料低温物理硬化与结晶性能为评价沥青在实际工程中的低温抗开裂能力提供了更准确的信息.聂忆华 孙世恒 丁海波 HESP Adrianus Maria Simon 2018建筑材料学报2018,21,4:5
6Morphology, dynamics, ecology and fauna of Arctotheca populifolia and Gazania rigens nabkha dunes显示文摘Patrick Hesp Anton McLachlan 2000Journal of Arid Environments2000,,2:3
7Foredunes and blowouts: initiation, geomorphology and dynamics显示文摘Patrick Hesp 2002Geomorphology2002,,1:3
8Recurrent abdominal complaints caused by a cecal neurofi broma:A case report显示文摘Gastrointestinal involvement of neurof ibromatosis type 1 (NF1, Von Recklinghausen’s disease) is generally associated with the upper gastrointestinal tract. Abdominal manifestation of NF1 includes several tumors such as malignant peripheral nerve sheath tumors, gastrointestinal stromal tumors and ampulla of vater tumors. However, colonic involvement in NF1 patients is rare. We report a case of a patient presenting with dysphagia, weight loss, intermittent abdominal pain and constipation caused by a single cecal neurof ibroma obstructing the ileocecal valve. Also gastrointestinal involvement of the lower tract should be considered in patients with NF1 presenting with abdominal complaints.Willem Donk Paul Poyck Pieter Westenend Wilco Lesterhuis Fried Hesp 2011World Journal of Gastroenterology2011,17,34:2
9Elastic steric stabilization of polyethylene-asphalt emulsions by using low molecular weight polybutadiene and devulcanized rubber tire显示文摘Morrison G Hedmark H Hesp S 1994Colloid and Polymer Science1994,272,:1
10Morphology, dynamics, ecology and fauna of Arctotheca populifolia and Gazania rigens nabkha dunes 显示文摘Hesp P McLachlan A 2000Journal of Arid Environments2000,44,2:1
11Flow dynamics over a foredune at Prince Edward Island 显示文摘Hesp P A Davidson - Arnott J Walker I J 2005Canada Geomorphology2005,65,12:1
12The formation of shadow dunes显示文摘Hesp P A 1981Journal of Sedimentary Research1981,51,1:1
13A new tracer method for the calculation of rates of bone formation and breakdown in osteoporosis and other generalised skeletal disorders显示文摘Reeve J Hesp R Wootton R 1976Calcif Tissue Res1976,22,2:1
14Correlations between chemical structure,stress-induced crystallization, an deformation behavior of polyurethane elastomers显示文摘Morbitzer L Hespe H 1972J Appl Polym Sci1972,16,10:1
15Wind flow and topographic steering within a tough blowout显示文摘Hesp P A Pringle A 2001Journal of Coastal Research2001,34,:1
16The formation of shadow dunes显示文摘Hesp P A 1981Sedimentary Petrology1981,51,:1
17Foredunes and blowouts: initiation, geomorphology and dynamics显示文摘Hesp P A 2002Geomorphology2002,48,:1
18Foredunes and blowouts:initiation,geomorphology and dynamics显示文摘Hesp P A 2002Geomorphology2002,48,:1
19Flow dynamics in a trough blowout显示文摘Hesp P A 1996Boundary- Layer Meteorology1996,77,:1
20Morphology, dynamics, eco显示文摘Hesp P McLachlan A 2000Journal of arid environments2000,44,2:1
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