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气象科技进展 2020年第5期10卷 177-177页

作者：张萌 Arabzadeh A ehsani m r Guan B

大气河(Ar)是大气低空急流层中水汽输送的狭长走廊。Zhu等在1994年首次提出了这一术语,以反映它们的狭窄及其对全球水循环的重要性。在任何给定的时刻,在每个半球大约有3～5个Ar,它们的宽度仅占全球中高纬度纬圈的10%不到,但其输送的水...

大气河(Ar)是大气低空急流层中水汽输送的狭长走廊。Zhu等在1994年首次提出了这一术语,以反映它们的狭窄及其对全球水循环的重要性。在任何给定的时刻,在每个半球大约有3～5个Ar,它们的宽度仅占全球中高纬度纬圈的10%不到,但其输送的水汽却占经向水汽通量的90%以上。

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遥感和再分析产品中大气河降水的全球比较

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气象科技进展 2020年第5期10卷 M0003-M0003页

作者： Arabzadeh A ehsani m r Guan B 张萌(编译) 不详

大气河(Ar)是大气低空急流层中水汽输送的狭长走廊。Zhu等在1994年首次提出了这一术语,以反映它们的狭窄及其对全球水循环的重要性。在任何给定的时刻,在每个半球大约有3~5个Ar,它们的宽度仅占全球中高纬度纬圈的10%不到,但其输送的水... 详细信息

大气河(Ar)是大气低空急流层中水汽输送的狭长走廊。Zhu等在1994年首次提出了这一术语,以反映它们的狭窄及其对全球水循环的重要性。在任何给定的时刻,在每个半球大约有3~5个Ar,它们的宽度仅占全球中高纬度纬圈的10%不到,但其输送的水汽却占经向水汽通量的90%以上。

关键词：水汽通量中高纬度低空急流大气河水汽输送全球水循环降水 Ar

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Shear modulus and damping ratio of sand-granulated rubber mixtures

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Journal of Central South University 2015年第8期22卷 3159-3167页

作者： m.ehsani N.Shariatmadari S.m.mirhosseini School of Civil Engineering Iran University of Science and Technology Department of Civil Engineering Amirkabir University of Technology

recycled waste tires when mixed with soil can play an important role as lightweight materials in retaining walls and embankments, machine foundations and railroad track beds in seismic zones. Having high damping characteristic, rubbers can be used as either soil alternative or mixed with soil to reduce vibration when seismic loads are of great concern. Therefore, the objective of this work was to evaluate the dynamic properties of such mixtures prior to practical applications. To this reason, torsional resonant column and dynamic triaxial experiments were carried out and the effect of the important parameters like rubber content and ratio of mean grain size of rubber solids versus soil solids(D50,r/D50,s) on dynamic response of mixtures in a range of low to high shearing strain amplitude from about 4×10-4% to 2.7% were investigated. Considering engineering applications, specimens were prepared almost at the maximum dry density and optimum moisture content to model a mixture layer above the ground water table and in low precipitation region. The results show that tire inclusion significantly reduces the shear modulus and increases the damping ratio of the mixtures. Also decrease in D50,r/D50,s causes the mixture to exhibit more rubber-like behavior. Finally, normalized shear modulus versus shearing strain amplitude curve was proposed for engineering practice.

关键词： sand-rubber mixture shear modulus damping ratio low to high shear strain amplitude cyclic triaxial test torsionalresonant column test granular rubber

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Structural,magnetic and electrical characterization of the La_(0.7)Ca_(0.3)Co_(1–x)mn_xO_3(x=0,0.7 and 1) compounds prepared by a simple method

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Journal of rare Earths 2014年第10期32卷 965-972页

作者： m.Eshraghi P.Kameli F.Khalili m.H.ehsani H.Salamati Department of Physics Payame Noor University Department of Physics Isfahan University of Technology Department of Physics Semnan University

Structural, magnetic and electrical properties of the La0.7Ca0.3Co1–xmnxO3（x=0, 0.7 and 1） samples prepared by a simple method were systematically studied and it was found that the crystal structure was transformed from rhombohedral for La0.7Ca0.3CoO3（LCCO） and La0.7Ca0.3Co0.3mn0.7O3（LCCmO） samples to orthorhombic for La0.7Ca0.3mnO3（LCmO） sample. The AC magnetic susceptibility measurements showed that LCCO sample underwent a transition from paramagnetic（Pm） to ferromagnetic（Fm） phase at Curie temperature, TC^155 K and below Curie temperature, the glassy ferromagnetism nature was observed. In LCCmO sample,clear evidence of spin glass（SG） state was observed at low temperature. Pm-Fm phase transition at about TC^260 K and long range Fm order at low temperatures were observed in LCmO sample. Both the LCCO and LCCmO samples exhibited insulating behavior in the whole range of measuring temperature whereas the LCmO sample underwent a clear metal-insulator（mI） transition at about TmI^263 K, corresponding to Curie temperature. metallic region of ρ（T） curve of the LCmO sample was fitted to the model of electron-electron and electron-magnon scattering. The charge carrier transport behavior in all the samples was compared based on polaronic models.

关键词： cobaltite spin glass manganites rare earths

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Selection and experimental evaluation of shaking rods of canopy shaker to reduce tree damage for citrus mechanical harvesting

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International Journal of Agricultural and Biological Engineering 2018年第2期11卷 48-54页

作者： Yingjun Pu Arash Toudeshki reza ehsani Fuzeng Yang Jaafar Abdulridha College of mechanical and Electronic Engineering Northwest A&F UniversityYangling 712100ShaanxiChina Citrus research&Education Center Institute of Food and Agricultural SciencesUniversity of FloridaLake AlfredFL 33850USA School of Engineering University of CaliforniaMercedCA 95343USA

Canopy shaking system is one of the research hotspots for large-scale mechanized fruits *** rods considered as one of the essential components of canopy shaker are responsible for transferring mechanical energy from shaking mechanism to different regions of tree *** transfer depends on the characteristics of the shaking rods that directly strike the tree *** order to evaluate the effects of the shaking rods on tree damage level and fruit removal percentage,three kinds of shaking rods with different materials or shapes were *** on the results of bending deformation tests,it was proven that the rigid shaking rod(r_(1))with the material of Polyvinyl Chloride(PVC)did more resistance against producing bending deformation in comparison with the other two types of shaking rods with the material of Polyamide Nylon 12(PA).By contrast,the position close to the free end of the flexible shaking rod was easier to be deformed by less external *** addition,dynamic analysis and vibration performance tests indicated that the rigid shaking rod could produce stronger vibration with higher shaking frequency of 4.8 Hz and maximum acceleration of 31.4 m/s^(2).Finally,the results of field trials indicated that the flexible bow-shaped shaking rod(r_(3))has a better widespread performance to achieve comparative higher fruit removal percentage up to 82.6%while producing lower tree damage rate of 5.36%.This study demonstrates that the materials or shapes of the shaking rod could significantly influence the fruit detachment rate and tree damage *** study would provide an essential reference for the application of shaking rods for canopy shaker.

关键词： citrus harvester shaking rod canopy shaker bending deformation tree damage fruit removal

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