作者:陈雪飞; 秦国良; 贾诚; 李元 期刊:《风机技术》 2019年第05期
In this paper,a correlation model between centrifugal compressor and its piping system is built based on plenum chamber model and throttle valve model.This model could be used to conduct numerical analysis of compressor systems from steady to surge operating points.Three dimensional unsteady numerical simulations were performed to predict the performance of a centrifugal compressor.The flow stru...
作者:刘艳; 赵鹏飞; 刘啸; 王杨; 石海 期刊:《风机技术》 2019年第05期
CFD method was employed to analyze the effect of the wall extension of hub and shroud at the impeller outlet(rotating diffuser)in a centrifugal compressor model stage with a large mass flow coefficient.The effect of clearance leakage was considered.Results show that the extended hub and shroud increases the head coefficient and ploytropic efficiency for the centrifugal compressor stage,and the e...
作者:Ming; Wang; Shaobao; Liu; Zhimin; Xu; Kai; Qu; Moxiao; Li; Xin; Chen; Qing; Xue; Guy; MGenin; Tian; Jianlu; Feng; Xu 期刊:《医用生物力学》 2019年第A01期
Flow of fluids within biological tissues often meets with resistance that causes a rate-and size-dependent material behavior known as poroelasticity.Characterizing poroelasticity can provide insight into a broad range of physiological functions,and is done qualitatively in the clinic by palpation.Indentation has been widely used for characterizing poroelasticity of soft materials,where quantitat...
作者:Qing; Hua; XU; Fang; FANG; Tai; Shun; LIU 期刊:《数学学报》 2017年第04期
Let Sα^* be the familiar class of normalized starlike functions of order α in the unit disk. Inthis paper, we establish the Fekete and Szego inequality for the class Sα^*, and then we generalize thisresult to the unit ball in a complex Banach space or on the unit polydisk in C^n.
作者:Wei; LI; Ji; LUO; Guoqing; JIA; Danli; YANG; Yongmei; HE 期刊:《生物技术》 2019年第05期
A field experiment was carried out to examine the soil respiration rate in Abies fabri forests in Gongga Mountain National Nature Reserve using LI-6400-09 portable soil respiration chamber.The results showed that the soil respiration rate and soil temperature of mature and middle-aged A.fabri forests were different in each month.The soil CO2 emission rates of the two stands had obvious seasonal ...
作者:周广盼; 李爱群; 李建慧; 端茂军 期刊:《中南大学学报·社会科学版》 2017年第10期
The present work is aimed at studying the mechanic properties of the extra-wide concrete self-anchored suspension bridge under static and dynamic vehicle loads. Based on the field test using 12 heavy trucks and finite element simulations, the static deformations of different components, stress increments and distributions of the girder, as well as the vibration characteristics and damping ratio ...
作者:He; Mingqian; Thomas; M.; Leslie 期刊:《合成化学》 2004年第Z1期
Chromophores are the center piece of second order nonlinear optical (NLO) materials.The common chromophore consists of a Donor-Bridge-Acceptor structure. Donors and acceptors are connected by a bridge and together they make a fully conjugated system. Based on our previously synthesized novelacceptors [1], we have synthesized a large number of high electro-optic chromophores. In this paper, we re...
作者:刘伟; 黄秀全; 王丁喜; 刘若阳 期刊:《风机技术》 2019年第01期
影响系数法长期以来被用于数值和实验方面的颤振分析研究。在实验研究中,实验装置通常采用3-11个叶片的线性或环形叶栅,并在上下两端放置挡板。实验中仅驱动中间叶片振动,在各叶片表面产生非定常压力,测量各叶片表面的非定常压力并采用影响系数法可以得到以行波模式振动时叶片表面的非定常压力。而我们在数值模拟中使用影响系数法时,不需要在上下两端放置挡板,通过采用周期性边界条件就可以保证流场的周期性。有些学者指出,当叶栅...
作者:Kezhong; Zhang; Li; Xu; Zhiyong; Feng; Ping; Zhang 期刊:《中国通信》 2019年第01期
Automatic Modulation Classification(AMC)is an important technology used to recognize the modulation type.A dictionary set was trained via signals with known modulation schemes in cooperative scenarios.Then we classify the modulation scheme of the signals received in the non-cooperative environment according to its sparse representation.Furthermore,we proposed a novel approach called Fast Block C...
作者:TANG; Yanli; YANG; Wenzhao; SUN; Liyuan; ZHAO; Fenfang; LONG; Xiangyu; WANG; Gang 期刊:《中国海洋大学学报·自然科学版》 2019年第01期
As a simplified model of artificial reefs,a series of plate models punched with square or circular openings are designed to investigate the effects of openings on the hydrodynamic characteristics of artificial reefs.The models are grouped by various opening numbers and opening-area ratios.They are physically tested in a water flume or used in the numerical simulation to obtain the drag force in ...
作者:于晓明; 李思颖 期刊:《红外技术》 2018年第12期
对运动目标跟踪时,主流Mean-Shift(均值偏移)算法对环境的影响较为敏感。针对目标遮挡时准确跟踪这一问题,提出了多步预测融合Mean-Shift的优化运动目标跟踪算法。在目标跟踪的过程当中采取Bhattacharyya coefficient(巴氏系数)辨别目标是否出现了遮挡。当目标产生遮挡的情况,采取多步预测算法,根据目标前一帧的特征信息对下一帧中目标位置信息进行判断。当运动目标离开遮挡时,则继续采取Mean-Shift实施后续跟踪。通过对不同场景下...
作者:楚彩云; 张宝泉; 刘秀凤; 林跃生 期刊:《化工学报》 2004年第06期
Ethanol has more accessible critical properties (Tc = 241℃, Pc =6.38 MPa) than water and stronger solubility power than carbon dioxide. Nearcritical and supercritical ethanol is a compressible fluid exhibiting great tunability with both temperature and pressure. It offers a great potential as an
作者: 期刊:《中国海洋大学学报·自然科学版》 2007年第01期
作者:蓝建华 期刊:《中国医疗器械信息》 2012年第11期
目的:探讨新版国际标准ISO 8637:2010中超滤系数的分析检测方案。方法:计算滤过液流率和跨膜压之间的回归线斜率作为超滤系数。结论:通过该方案可以确定血液透析器产品的超滤系数。
作者:马海波 崔广柏 常文娟 期刊:《水电能源科学》 2010年第09期
针对当前河流纵向离散系数计算方法的缺陷,提出了一种利用改进的BP神经网络模型计算河流纵向离散系数的新方法.实例应用结果表明,该法增强了BP网络预测的精度和泛化能力,可简单、有效地预测河流纵向离散系数.
作者:成洁筠 杨建军 唐小弟 期刊:《中南大学学报·社会科学版》 2008年第S1期
In order to get the formulae for calculating the equivalent frame width coefficient of reinforced concrete hollow slab-column structures with edge beam,the finite element structural program was used in the elastic analysis of reinforced concrete hollow slab-column structure with different dimensions to study internal relationship between effective beam width and the frame dimensions.In addition,...
作者:刘长生 期刊:《中南大学学报·社会科学版》 2008年第S1期
The adhesion coefficient of automobile tire and road surface was analyzed and the formula about it was derived.Some suggestions about highway construction,driving safety of the drivers and the judgment of the traffic accidents were presented.The results show that the adhesion coefficient is a function with the extreme value.If there is atmospheric pressure in the tire,the load of the vehicle and...
作者:丁科 唐小弟 期刊:《中南大学学报·社会科学版》 2008年第S1期
Based on constitutive theory of viscoelasticity,the viscoelastic behaviour of concrete pile was investigated.The influence of viscosity coefficient on the stress,displacement and velocity response was discussed.With the increase of viscosity coefficient,the amplitude of stress wave decreases,and the maximum value of the stress wave shifts to deeper position of the pile.In other words,the viscosi...
作者:李福琴 涂金忠 期刊:《科学技术与工程》 2010年第05期
通过CCEBC方法讨论一类带两个平方项的三维混沌系统的动力学行为。其次,运用theflint Lypaunovcoefficient方法研究混沌系统的Hop分岔,得到了系统发生亚临界或超临界H0pf分岔的区间范围。
作者:姚庆六 Qing-liu 期刊:《吉首大学学报·自然科学版》 2010年第06期
研究了变系数非线性三阶用期边值问题的正解,非线性项可以关于空间变元奇异.利用适当的变换此问题被转换为一个Hammerstein积分方程,利用锥上的Guo-Krasno-serski不动点定理获得了1~2个正解的存在性. Abstract: The positive solutions of a nonlinear third-order periodic boundary value problem with variable coefficient are studied.The nonlinear term may be singular with respect to the space variable.By making us...