大尺度
- 与 大尺度 相关的网络例句 [注:此内容来源于网络,仅供参考]
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Based on the theory of large eddy simulation and the method of VOF , the initial breakup process of fuel liquid jet, which eject from the nozzle exit at the time scale of micro-second level, is investigated. The mechanism of primary atomization is analyzed, and the initial breakup model of liquid jet is presented. By modeling and numerical simulation of atomization for a diesel nozzle under the given conditions, the initial umbrella-like spray shapes are obtained, which fits better with the experimental results. Meanwhile, the droplets secondary breakup process, such as leeward RT breakup, dumbbell-like breakup and droplets coalescence, etc. are exhibited visually.
基于大涡模拟LES理论和VOF方法,考察了燃油喷雾初始时刻即时间尺度为微秒级的液柱破碎过程,分析了初始破碎的机理,给出了该时间尺度下液柱初始破碎过程的模型;通过对一特定条件下的柴油机喷油器的建模和喷雾过程的大涡数值模拟,获得了液柱初始时刻"伞状头部"的喷雾形态,所得计算结果与相应的试验数据符合较好;数值模拟还直观地展现了液滴背风RT破碎、哑铃型破碎以及液滴的聚集融合等液滴的二次雾化过程。
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Phase structure function and aperture-averaged slope correlation function with finite outer scale are derived.
导出了有限外尺度影响下的相位结构函数和孔径平均的斜率相关函数的表达式,结果表明有限的大气外尺度对大气湍流统计特征的测量有很大的影响,尤其对大尺寸的望远镜和子孔径更是如此。
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The study has shown:(1) With increasing sediment depth and the woody giblets, the total organic carbon, the extraction of benzene , the total humic acids and the unhydrolyte are enhanced, while the hydrolyte is decreasing.(2) According to the GC-MS analysis, n-alkane,n-alkan-2-ones and n-alkanones are composed mainly of long-chains,such a result is thought to be characteristic of a herbaceous input from 2300a.B.P. n-alkanones exist in the samples may be considered as the evidence of microorganisms activity.(3) It is showed that the lipids is more sensitive to the climate change than the floristic. The proxy of the pollen spore of the peat stratum is different from the normal environment proxy. It is one of the main reasons that the sensitivity difference of the bog vegetation reacting to the climate isn't accordant with the log of the fat molecule fossil and biology fossil.(4) The transformation of the peat organic carbon is under the influence of temperature,acidity,organic material constituting, etc, and it showed the up-trend with the depth. In the short-term scale, the conversion of the peat organic carbon is effected by seasonal water,regional climate and vegetations; while in the long-term scale, it is controlled mainly by the climate.(5) According to the comparing the orderliness of organic compound,vegetation giblets with the depth to the characteristics of the peat molecule fossil with the section, in the development of this peatmire, 1500a B.P(210cm)is regard as the borderline of the late Holocene, the keynote of the front period is warm with several cold fluctuations, and the trend of the back period is dry and cold although there were several fluctuations.
研究表明:(1)随深度的增高及植物残体中木本残体的增多,总有机碳、苯萃取物、总腐植酸、不被水解物含量逐渐增高,而易水解物含量减少;(2)GC- MS分析显示,正构烷烃,直链烷基2-酮和正烷醇均以长链组分为主,揭示了该泥炭柱剖面2347a.B.P的母源输入以草本植物为主;甲基酮类和短链正烷醇的存在是微生物活性很大的生物证据;(3)通过有机分子标志物与孢粉、植物残体等指标的对比研究表明:脂类化合物对气候变化的反映要比植物种灵敏得多,不同沼泽植物对气候变化的敏感性的差异是脂类分子化石记录与生物大化石结果很难一致的主要原因之一;(4)泥炭有机碳的转化受到温度、酸度、有机物质组成等很多因素的影响,短时间尺度,泥炭有机碳的转化受季节性降水、地方气候和植被等因素的影响;长时间尺度,泥炭地有机碳的转化,受气候条件控制;(5)总结泥炭分子化石特征、泥炭有机质各组分含量及植物残体组成随深度的变异规律,分析结果显示该泥炭地层形成过程中,1500a B.P(210cm)可作为划分前后晚全新世的界线,前期的基调是气候偏暖,但又有几次偏干冷气候的反复,后期气候以干冷为主,其间虽有几次上升波动,但整体趋势不变。
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Numerical results show that constant coagulation kernel has more influences on small particles than linear and quadratic coagulation kernel,whereas has less influences on big particles than linear and quadratic coagulation kernel;in the same wa...
发现常凝并核要比线性和二次方凝并核对小颗粒的影响大一些、对大颗粒的影响小一些,线性和二次方凝并核对颗粒尺度分布的时间演变影响则取决于具体情况;常冷凝核要比线性冷凝核对小颗粒的影响大一些、对大颗粒的影响小一些;连续区布朗凝并核类似于常凝并核;扩散冷凝核对颗粒尺度分布的影响界于常冷凝核和线性冷凝核之间。
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At leaf scale, TJ photosynthesis model was selected and Gao stomatal conductance model was proved suitable for semi-arid region after comparing with BBL model through the parameter regression and analysis of model sensitivity. Plant physio-ecological characteristics were analyzed based on the parameters gained from the nonlinear regression using TJ model and Gao model with field experimental data. As C4 photosynthesis types Zea mays and Panicum miliaceum 's carboxylation coefficient are bigger than the others.
在叶片尺度上,选择TJ模型作为叶片尺度所使用的光合模型,并对景观模拟中经常用到的Ball-Berry模型和Gao模型进行比较,通过参数拟合和模型的敏感性分析,选择Gao模型作为叶片尺度的气孔导度模型,应用模型模拟的结果,分析了研究区主要植物种的生理生态学特性。C4光合型的玉米和糜子,羧化速率系数大,光合能力强。
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; 3 younger Dryas Only has reflection in the hundred-year-scales climatic curve, it is not evident in the curve of long period; 4 in the hundred-year-scales climatic curve, the last glacial maximum fluctuation as frequuently and 18-28KaBP was the stage in which the frequency fluctuation was the largest.
;(3)新仙女木事件仅反映在百年尺度的气候曲线上,在较长周期的饿曲线上不明显;(4)在百年尺度的气候曲线中,末次冰盛期气候波动频繁,其中18-28KaBP 是频率波动的最大阶段,但随着周期尺度的加大,气候的波动频率逐渐趋于均匀。
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Regardless to the research development or industrial application, nano metal powders are extensively discussed. Within these powders, the flammable and explosible nano aluminum, titanium and iron powders produce a great amount production and apply widely. Meanwhile, the surface/volume ratio of powders is increased significantly under nano scale, in which to enhance the ignition opportunity. Thus, the dust explosion hazard risk of nano powders could remarkable rise. In addition, the comparison of explosion phenomenon, test methods and quantification parameters between nano and micro scale is necessary to deeply investigate further. So that this project operates the explosion characteristic experiments to measure and determine such the maximum explosion pressure, minimum explosion concentration and explosion characteristic Kst value on above mentioned three nano metal powders. Expectantly, to provide the appropriate recommendations of safety prevention for nano dust explosion based on the experimental results.
奈米金属粉末无论是研究发展或是工业界应用,目前皆是广泛讨论研究之材料,其中,奈米铝粉、奈米钛粉以及奈米铁粉等可燃、爆性粉末,均有高额产量及大量应用领域,与此同时,在粉末粒径进入奈米尺度的情况下,粉尘比表面积大幅提升,增加此三种粉尘可被点燃的机会,因此,潜在的粉尘爆炸危害风险将广幅增加,另外,微米尺度粉尘爆炸的现象、测试方法以及量化参数是否具有相同的实验尺度基点,也需要深入探讨,故本次计画针对上述三种奈米金属粉末,进行三种不同粒径的爆炸特性参数实验,如最大爆炸压力、最低爆炸浓度以及爆炸特性参数Kst值之量测与计算,期能量化其粉尘爆炸特性,并据此提出适当的安全防护建议。
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When the receiving aperture is much larger than the scattering disk scale, the aperture-smooth effect is remarkable and the derived variance approximates the result given by weak-fluctuation theory for any zenith; when the receiving aperture is much smaller than the scattering disk scale, the low-pass filter effect of the scattering disk scale is dominating and weak-fluctuation theory is valid only for small zeniths.
散射盘尺度和接收孔径对到达角起伏起平滑作用,当接收孔径远大于散射盘尺度时,由于孔径平滑作用,导出的表达式在任意天顶角都可以近似为弱起伏理论给出的结果;当接收孔径小于散射盘尺度时,散射盘尺度的平滑作用明显,接收孔径的平滑作用相对较小,传统的到达角起伏理论仅在小天顶角是适用的,在大天顶角必须用新导出的方差表达式。
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We performed a simulative test, which confirms that wavelet analysis can separate annual wobble and Chandler wobble. Our results show that this method can be used in astronomical geodynamies effectively. This paper is divided into two parts. The first is about statistic characteristic of polar motion. Polar motion includes secular motion, long period fluctuations, Chandler wobble, annual wobble and high frequency wobble. The secular motion is 3.4mas/year and towards 760W meridian. Long period fluctuations have difference periods in x-axis and y-axis. They are 31.7-year and 24-year in x-axis and 28.5-year and 22.9-year in y-axis. These 2~? decades fluctuations have an amplitude of about 30 mas , and are very nearly linearly polarized, with the observed motion of pole being almost entirely along a line between 360E and 1440W. There is a 55.4-year wobble whose amplitude is 9 mas. The amplitude of the interannual fluctuations is about 4? mas. The amplitude of long period fluctuations decreased after 1970. The annual wobble is a steady wobble. It retrograde wobble is only 1/20 of prograde wobble in amplitude.
本文的工作主要分为两部分:第一部分是通过分析POLE97序列,我们对极移的统计特性有了一个较全面的认识,极移主要包括趋势项、长周期项、Chandler项、周年项和高频项:趋势项的方向是西经76°,速度为每年3.4mas;长周期项中Markowitz 项在X、Y两个方向有不同的周期,它们分别是:X方向的两个周期是31.7年和24 年,Y方向的两个周期为28.5年和22.9年它们叠加在一起是一个线偏振运动,最大振幅约为30mas,偏振方向在西经144°和东经36°之间;极移的长周期波动中还存在一个 55.4年周期的圆周运动,振幅约为9mas;十年尺度变化的振幅在4~6mas之间,在Y 方向十年尺度的成份比较多,它们的周期在X方向和Y方向不是对应的;从七十年代年开始长周期变化的振幅明显降低;周年项是一个振幅稳定的摆动,在X、Y两个方向的振幅略有差别,逆向运动振幅大约为顺向运动振幅的1/20;Chandler摆动的振幅自1900年以来经历了几次较大的变化,其中包括1915年和1955年两次极大值,振幅分别达到0&。25和0&。28,以及1925~1940期间小于0.09的过程,Chandler项在X、Y 两个方向的振幅几乎完全相等,其逆向运动振幅不到顺向运动振幅的1/50。
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It was the first time that experimental studies of the flow characteristics and convective heat transfer in platelet regenerative cooling channels with high aspect ratio were conducted in China.
大高宽比再生冷却套在宽度上已属于微小通道,为考察其流动传热是否与常规尺度管道不同,本文理论分析采用经典N-S方程而未考虑微小尺度效应是否合理,研究流道高宽比等几何参数对其水力和对流换热特性的影响,分别搭建了挤压式水力实验台和泵压式对流换热实验台,设计了d〓=1.0~1.2mm,宽度为0.6~0.8mm,AR=3~15的5个不同高宽比矩形通道层板试验件,采用线切割加工槽道和扩散焊接盖板的制造工艺,得到了质量可靠的试验件,以水为工质,在国内首次对大高宽比层板再生冷却通道的流动和对流换热特性进行了实验研究。
- 推荐网络例句
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The split between the two groups can hardly be papered over.
这两个团体间的分歧难以掩饰。
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This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.
这种做法不仅鼓励了更多的反应,而且减少跟风的可能性。
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The new PS20 solar power tower collected sunlight through mirrors known as "heliostats" to produce steam that is converted into electricity by a turbine in Sanlucar la Mayor, Spain, Wednesday.
聚光:照片上是建在西班牙桑路卡拉马尤城的一座新型PS20塔式太阳能电站。被称为&日光反射装置&的镜子将太阳光反射到主塔,然后用聚集的热量产生蒸汽进而通过涡轮机转化为电力