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应用“均度法”对磨牙磨耗与年龄关系的初步研究 被引量:2
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作者 李春彪 纪贵金 《中国医科大学学报》 CAS CSCD 1991年第3期196-199,共4页
本文应用首创的牙齿磨耗分度法—平均磨耗度法(简称“均度法”)对94例东北人的518颗磨牙磨耗程度与年龄的关系进行了初步研究。材料年龄范围为15岁~71岁。经直线回归分析得到4个牙齿磨耗度与年龄关系的回归方程式。统计及回代结果表明... 本文应用首创的牙齿磨耗分度法—平均磨耗度法(简称“均度法”)对94例东北人的518颗磨牙磨耗程度与年龄的关系进行了初步研究。材料年龄范围为15岁~71岁。经直线回归分析得到4个牙齿磨耗度与年龄关系的回归方程式。统计及回代结果表明,均度法能较以往方法更客观、更全面、更科学地反映整个牙齿的磨耗情况,推断出的年龄更加准确,且可避免某些咬关系对推断年龄的影响。 展开更多
关键词 磨牙 牙齿磨耗 年龄 均度法
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Evaluation model of individual thermal comfort based on mean skin temperature 被引量:10
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作者 刘蔚巍 连之伟 邓启红 《Journal of Southeast University(English Edition)》 EI CAS 2010年第2期254-257,共4页
The local skin temperatures of 22 subjects at air temperatures of 21,24,26,29 ℃ are measured,and the mean skin temperatures are calculated by ten skin temperature measuring points.The thermal comfort levels and the t... The local skin temperatures of 22 subjects at air temperatures of 21,24,26,29 ℃ are measured,and the mean skin temperatures are calculated by ten skin temperature measuring points.The thermal comfort levels and the thermal sensations of these subjects are also investigated by a questionnaire.The Mahalanobis distance discrimination method is applied to establish the evaluation model for the thermal comfort based on the mean skin temperature.The experimental results indicate that the difference of the mean skin temperatures between the comfort level and the discomfort level is significant.Using the evaluation model,the mean skin temperature at the thermal comfort level is 32.6 to 33.7 ℃,and the thermal comfort levels of 72% of the subjects are correctly evaluated.The accuracy of the evaluation model can be improved when the effects of sex of the subject on the mean skin temperature and the thermal comfort are considered.It can be concluded that the mean skin temperature can be used as an effective physiological indicator to evaluate human thermal comfort in a steady thermal environment. 展开更多
关键词 thermal comfort mean skin temperature Mahalanobis distance discrimination method THERMOREGULATION
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Flow Field Around Rushton Turbine in Stirred Tank by Particle Image Velocimetry Measurement 被引量:7
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作者 高殿荣 ACHARYA Sumanta +1 位作者 王益群 UHM Jongho 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2004年第6期843-850,共8页
In this paper, particle image velocimetry (PIV) was used to measure the mean and root meansquare(RMS) velocity in the stirred tank with six-flat blade Rushton turbine and with no baffles. Two typesof motion patterns w... In this paper, particle image velocimetry (PIV) was used to measure the mean and root meansquare(RMS) velocity in the stirred tank with six-flat blade Rushton turbine and with no baffles. Two typesof motion patterns were studied. One was that the impeller runs at constant speed, the other was that the impellerruns at time-dependent speed and in a periodic way. The emphasis of the paper was on the comparison of meanand RMS velocity vector maps and profiles between these two types of motion patterns, and especial attention waspaid to the comparison of the mean velocity, time-averaged RMS velocity, phase averaged RMS velocity betweenthe constant 3 RPS (revolution per second) and time-dependent operation. The Reynolds number was between 763and 1527. The study explained the mechanism that time-dependent RPS is more efficient for mixing than that ofconstant RPS. 展开更多
关键词 particle image velocimetry mean velocity stirred tank root mean squarevelocity time-dependent speed
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ANALYSIS AND DESIGN OF THE STABLE PARALLEL PACKET SWITCH
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作者 DongYuguo LiZupeng +1 位作者 GuoYunfei WuJiangxin 《Journal of Electronics(China)》 2005年第2期161-170,共10页
This paper analyzes the Parallel Packet Switch(PPS) architecture and studies how to guarantee its performance. Firstly a model of Stable PPS (SPPS) is proposed. The constraints of traffic scheduling algorithms, the nu... This paper analyzes the Parallel Packet Switch(PPS) architecture and studies how to guarantee its performance. Firstly a model of Stable PPS (SPPS) is proposed. The constraints of traffic scheduling algorithms, the number of switching layers and internal speedup, for both bufferless and buffered SPPS architecture, are theoretically analyzed. Based on these results, an example of designing a scalable SPPS with 1.28T capacity is presented, and practical considerations on implementing the scheduling algorithm are discussed. Simulations are carried out to investigate the validity and delay performance of the SPPS architecture. 展开更多
关键词 Parallel Packet Switch(PPS) LOAD-BALANCING SCHEDULING Distributed algorithm
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Soft Direct-Adaptation Based Bidirectional Turbo Equalization for MIMO Underwater Acoustic Communications 被引量:5
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作者 Junyi Xi Shefeng Yan +1 位作者 Lijun Xu Jing Tian 《China Communications》 SCIE CSCD 2017年第7期172-183,共12页
This paper proposes a soft direct-adaptation based bidirectional turbo equalizer for multiple-input multiple-output underwater acoustic communication systems. Soft, rather than hard, direct-adaptation based equalizer ... This paper proposes a soft direct-adaptation based bidirectional turbo equalizer for multiple-input multiple-output underwater acoustic communication systems. Soft, rather than hard, direct-adaptation based equalizer combined with the fast self-optimized least mean square algorithm is employed to achieve a faster convergence rate, and the second-order phase-locked loop is embedded into the equalizer to track the time-varying channel. Meanwhile, by utilizing a weighted linear combining scheme, the conventional soft direct-adaptation based equalizer is combined with the time-reversed soft direct-adaptation based equalizer to exploit bidirectional diversity and mitigate error propagation. Both the simulation and experimental results demonstrate that the soft direct-adaptation based bidirectional turbo equalizer outperforms the single-direction soft direct-adaptation based turbo equalizer, and achieves a faster convergence rate than the hard direct-adaptation based bidirectional turbo equalizer. 展开更多
关键词 soft direct-adaptation based turbo equalizer bidirectional turbo equalizer multipie-input multiple-output underwater acoustic communications
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3D FEM simulations and experimental validation of plastic deformation of pure aluminum deformed by ECAP and combination of ECAP and direct extrusion 被引量:5
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作者 Mohamed Ibrahim Abd EL AAL 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2017年第6期1338-1352,共15页
Rigid-viscoplastic3D finite element simulations(3D FEM)of the equal channel angular pressing(ECAP),thecombination of ECAP+extrusion with different extrusion ratios,and direct extrusion of pure aluminum were performed ... Rigid-viscoplastic3D finite element simulations(3D FEM)of the equal channel angular pressing(ECAP),thecombination of ECAP+extrusion with different extrusion ratios,and direct extrusion of pure aluminum were performed andanalyzed.The3D FEM simulations were carried out to investigate the load-displacement behavior,the plastic deformationcharacteristics and the effective plastic strain homogeneity of Al-1080deformed by different forming processes.The simulationresults were validated by microstructure observations,microhardness distribution maps and the correlation between the effectiveplastic strain and the microhardness values.The3D FEM simulations were performed successfully with a good agreement with theexperimental results.The load-displacement curves and the peak load values of the3D FEM simulations and the experimentalresults were close from each other.The microhardness distribution maps were in a good conformity with the effective plastic straincontours and verifying the3D FEM simulations results.The ECAP workpiece has a higher degree of deformation homogeneity thanthe other deformation processes.The microhardness values were calculated based on the average effective plastic strain.Thepredicted microhardness values fitted the experimental results well.The microstructure observations in the longitudinal andtransverse directions support the3D FEM effective plastic strain and microhardness distributions result in different formingprocesses. 展开更多
关键词 equal channel angular pressing (ECAP) EXTRUSION finite element method (FEM) MICROHARDNESS deformation homogeneity microstructure
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An algorithm for segmentation of lung ROI by mean-shift clustering combined with multi-scale HESSIAN matrix dot filtering 被引量:7
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作者 魏颖 李锐 +1 位作者 杨金柱 赵大哲 《Journal of Central South University》 SCIE EI CAS 2012年第12期3500-3509,共10页
A new algorithm for segmentation of suspected lung ROI(regions of interest)by mean-shift clustering and multi-scale HESSIAN matrix dot filtering was proposed.Original image was firstly filtered by multi-scale HESSIAN ... A new algorithm for segmentation of suspected lung ROI(regions of interest)by mean-shift clustering and multi-scale HESSIAN matrix dot filtering was proposed.Original image was firstly filtered by multi-scale HESSIAN matrix dot filters,round suspected nodular lesions in the image were enhanced,and linear shape regions of the trachea and vascular were suppressed.Then,three types of information,such as,shape filtering value of HESSIAN matrix,gray value,and spatial location,were introduced to feature space.The kernel function of mean-shift clustering was divided into product form of three kinds of kernel functions corresponding to the three feature information.Finally,bandwidths were calculated adaptively to determine the bandwidth of each suspected area,and they were used in mean-shift clustering segmentation.Experimental results show that by the introduction of HESSIAN matrix of dot filtering information to mean-shift clustering,nodular regions can be segmented from blood vessels,trachea,or cross regions connected to the nodule,non-nodular areas can be removed from ROIs properly,and ground glass object(GGO)nodular areas can also be segmented.For the experimental data set of 127 different forms of nodules,the average accuracy of the proposed algorithm is more than 90%. 展开更多
关键词 HESSIAN matrix multi-scale dot filtering mean-shift clustering segmentation of suspected areas lung computer-aideddetection/diagnosis
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Color image segmentation using mean shift and improved ant clustering 被引量:3
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作者 刘玲星 谭冠政 M.Sami Soliman 《Journal of Central South University》 SCIE EI CAS 2012年第4期1040-1048,共9页
To improve the segmentation quality and efficiency of color image,a novel approach which combines the advantages of the mean shift(MS) segmentation and improved ant clustering method is proposed.The regions which can ... To improve the segmentation quality and efficiency of color image,a novel approach which combines the advantages of the mean shift(MS) segmentation and improved ant clustering method is proposed.The regions which can preserve the discontinuity characteristics of an image are segmented by MS algorithm,and then they are represented by a graph in which every region is represented by a node.In order to solve the graph partition problem,an improved ant clustering algorithm,called similarity carrying ant model(SCAM-ant),is proposed,in which a new similarity calculation method is given.Using SCAM-ant,the maximum number of items that each ant can carry will increase,the clustering time will be effectively reduced,and globally optimized clustering can also be realized.Because the graph is not based on the pixels of original image but on the segmentation result of MS algorithm,the computational complexity is greatly reduced.Experiments show that the proposed method can realize color image segmentation efficiently,and compared with the conventional methods based on the image pixels,it improves the image segmentation quality and the anti-interference ability. 展开更多
关键词 color image segmentation improved ant clustering graph partition mean shift
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Determination of Rhodamine B in Food Using HPLCUV Method 被引量:2
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作者 WANG Yong WU Na 《Chinese Food Science》 2012年第2期37-39,共3页
[ Objective] The aim was to establish a method for the determination of Rhodamine B in food by HPLC-UV. [ Metkod] Rhodamine B was extracted with acetone/hexane from food samples. After concentrated and purified by alu... [ Objective] The aim was to establish a method for the determination of Rhodamine B in food by HPLC-UV. [ Metkod] Rhodamine B was extracted with acetone/hexane from food samples. After concentrated and purified by alumina cartridge, the Rhodamine B content in the food was determined by using high performance liquid chromatography with ultraviolet visible detector. [ Result] Within tile concentration range of 0.005 - 2.000 mg/kg, the peak area of Rhodamine B presented good linear relation with the concentration, and the related coefficient was 0.999 98. With high average recovery rate, the detection limit of the method was 0.005 mg/kg[ Concision] It is a fast and accurate method with high sensitivity to detect Rhodamine B in food. 展开更多
关键词 FOOD HPLC-UV Rhodamine B DETECTION China
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Dynamic analysis of new type elastic screen surface with multi degree of freedom and experimental validation 被引量:6
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作者 宋宝成 刘初升 +1 位作者 彭利平 李珺 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第4期1334-1341,共8页
A feasible method was proposed to improve the vibration intensity of screen surface via application of a new type elastic screen surface with multi degree of freedom(NTESSMDF). In the NTESSMDF, the primary robs were c... A feasible method was proposed to improve the vibration intensity of screen surface via application of a new type elastic screen surface with multi degree of freedom(NTESSMDF). In the NTESSMDF, the primary robs were coupled to the main screen structure with ends embedded into the elastomers, and the secondary robs were attached to adjacent two primary robs with elastic bands. The dynamic model of vibrating screen with NTESSMDF was established based on Lagrange's equation and the equivalent stiffnesses of the elastomer and elastic band were calculated. According to numerical simulation using the 4th order Runge-Kutta method, the vibration intensity of screen surface can be enhanced substantially with an averaged acceleration amplitude increasing ratio of 72.36%. The primary robs and secondary robs vibrate inversely in steady state, which would result in the friability of materials and avoid stoppage. The experimental results validate the dynamic characteristics with acceleration amplitude rising by62.93% on average, which demonstrates the feasibility of NTESSMDF. 展开更多
关键词 vibrating screen elastic screen surface multi degree of freedom dynamic analysis mesh stoppage prevention
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A New Model for Prediction of Mean Liquid Circulating Velocity in Bubble Columns
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作者 陈启明 吴元欣 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2000年第4期385-387,共3页
A new model without any fitting parameter for estimating the mean liquid recirculating velocity has been derived from previous work directly. The prediction agrees with experimental data reasonably well. Accurency of ... A new model without any fitting parameter for estimating the mean liquid recirculating velocity has been derived from previous work directly. The prediction agrees with experimental data reasonably well. Accurency of prediction from the new model is comparable with the models reported in the literature. However, the new model has a potential capability to predict the average liquid recirculation velocity at elevated pressure bubble columns since n and c is developed under pressure. However this needs to be further tested experimentally. 展开更多
关键词 mean liquid velocity correlation prediction bubble column
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A method for correcting regional bias in SMOS global salinity products
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作者 佟晓林 王振占 李青侠 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2015年第4期1072-1084,共13页
Soil Moisture and Ocean Salinity (SMOS) Level 3 (L3) sea surface salinity (SSS) products are provided by the Barcelona Expert Centre (BEC). Strong biases were observed on the SMOS SSS products, thus the data f... Soil Moisture and Ocean Salinity (SMOS) Level 3 (L3) sea surface salinity (SSS) products are provided by the Barcelona Expert Centre (BEC). Strong biases were observed on the SMOS SSS products, thus the data from the Centre Aval de Traitement des Donnees SMOS (CATDS) were adjusted for biases using a large-scale correction derived from observed differences between the SMOS SSS and World Ocean Atlas (WOA) climatology data. However, this large-scale correction method is not suitable for correcting the large gradient of salinity biases. Here, we present a method for the correction of SSS regional bias of the monthly L3 products. Based on the stable characteristics of the large SSS biases from month to month in some regions, corrected SMOS SSS maps can be obtained from the monthly mean values after removing the regional biases. The accuracy of the SMOS SSS measurements is greatly improved, especially near the coastline, at high latitudes, and in some open ocean regions. The SMOS and ISAS SSS data are also compared with Aquarius SSS to verify the corrected SMOS SSS data. The correction method presented here only corrects annual mean biases. The measurement accuracy of the SSS may be improved by considering the influence of atmospheric and ocean circulation in different seasons and years. 展开更多
关键词 ocean salinity microwave radiometry sea surface Soil Moisture and Ocean Salinity (SMOS)
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Adaptive Rate Control Scheme for H.264/AVC
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作者 Myoung-jin KIM Min-cheol HONG 《Journal of Measurement Science and Instrumentation》 CAS 2010年第2期192-195,共4页
The purpose of this paper is to improve allocation of the number of bits without skipping the frame by accurately estimating the target bits in H. 264/AVC rate control. The scheme ImPoses an enhancement method of the ... The purpose of this paper is to improve allocation of the number of bits without skipping the frame by accurately estimating the target bits in H. 264/AVC rate control. The scheme ImPoses an enhancement method of the target frame rate based on H. 264/AVC bit allocation. The enhancement uses a frame complexion estimation to improve the existing Mean Absolute Difference (MAD) complexity measurement. Bit allocation to each frame is not just computed by target frame rote but also adjusted by a combined frame complexity measure. Using the statistical characteristic, the scheme obtains change of occurrence bit about QP to apply the bit amount by QP from the video characteristic and apply it in the estimated bit amount of the current frame. Simulation results show that the proposed rate eontrol scheme achieves time saving of mine than 99% over existing rate control algorithm. Nevertheless, Peak Signal-to-Noise Ration (PSNR) and bit rate were almost the same as the performances. 展开更多
关键词 computational complexity Mean Absolute Difference rote control Peak Signal-to-Noise Ration
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Comparison of Absolute Distance Measurement by Different Types of Dual Mode-Locked Fiber Lasers
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作者 Tze-An Liu Yi-Chen Chuang +2 位作者 Hau-Wei Lee Po-Er Hsu Jin-Long Peng 《Journal of Mechanics Engineering and Automation》 2015年第12期676-680,共5页
Two types of the dual mode-locked fiber lasers for asynchronous absolute distance measurement are investigated, The lasers are linear and ring cavity with repetition rate of 70 MHz and 100 MHz, respectively. The group... Two types of the dual mode-locked fiber lasers for asynchronous absolute distance measurement are investigated, The lasers are linear and ring cavity with repetition rate of 70 MHz and 100 MHz, respectively. The group velocity dispersion is not compensated in the first type of the lasers, while the others are fully done. The timing jitter with the Allan deviation below averaging time of 0.2 s during the distance measurement for around 1 m of both types of lasers were 2.5 ps with 600 nm and 1.6 ps with 200 nm. We concluded that the phase noise resulted from the intra-cavity dispersion is the main contribution for the uncertainty of the ranging in these two types of the lasers. 展开更多
关键词 MODE-LOCKED fiber laser DISTANCE timing jitter.
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Use of Non-uniform Rational B-splines for Discharge Calculation in the Velocity Area Method
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作者 Zbigniew Krzemianowski Adam Adamkowski 《Journal of Energy and Power Engineering》 2014年第5期911-919,共9页
The velocity area method belongs to the group of primary methods for discharge measurement in hydropower plants. The measurements require an appropriate application of measuring devices and carrying out correctly the ... The velocity area method belongs to the group of primary methods for discharge measurement in hydropower plants. The measurements require an appropriate application of measuring devices and carrying out correctly the process of data analyzing including integration technique. The authors present their own experiences gathered during many years of utilizing the current meter method for discharge measurement in many hydropower plants. They have developed the special integration techniques using the progressive numerical algorithms. The techniques differ from the recommendations contained in the relevant international standards. The authors' own software for calculating the discharge from the measured local velocity distribution (obtained using current meters) adopts advanced spline functions, the so-called NURBS (non-uniform rational B-splines). Nowadays, this kind of splines is commonly used in modeling of the complex geometrical shapes because of their smoothness. It is assessed that it represents much better quality of interpolation than the classic spline functions (classic cubic spline technique). Particularly, the better properties of the NURBS splines can be observed for velocity profile area characterized by very strong velocity gradients where boundary layers meet the core regions of the flow (mainstream). In the developed software the boundary layer thickness and exponent of von Karman function is calculated in accordance with the ISO 3354 standard. The software has been successfully used during many performance tests of the hydraulic turbines in Poland for several years. Paper presents the results of flow rate measurements for two different flow systems of Kaplan turbines. First case concerns the application of the current meters in a long circular penstock whereas the second one in short rectangular turbine intake. A comparative analysis of three flow calculation procedures applied for these two cases is presented in the paper-(1) the integration procedure according to the ISO 3354 standard; (2) the integration procedure based on the NS (natural splines); and (3) the integration procedure based on the NURBS. The results obtained using these three procedures for the first case (intake via long circular penstock) were compared with the results of discharge measurements conducted using the pressure-time method. 展开更多
关键词 HYDROPOWER discharge measurements current meter method pressure-time method.
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An Adaptive Genetic Algorithm for Multiprocessor Real-time Task Scheduling
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作者 李亚军 杨宇航 《Journal of Donghua University(English Edition)》 EI CAS 2009年第2期111-118,共8页
Real-time task scheduling is of primary significance in multiprocessor systems.Meeting deadlines and achieving high system utilization are the two main objectives of task scheduling in such systems.In this paper,we re... Real-time task scheduling is of primary significance in multiprocessor systems.Meeting deadlines and achieving high system utilization are the two main objectives of task scheduling in such systems.In this paper,we represent those two goals as the minimization of the average response time and the average task laxity.To achieve this,we propose a genetic-based algorithm with problem-specific and efficient genetic operators.Adaptive control parameters are also employed in our work to improve the genetic algorithms' efficiency.The simulation results show that our proposed algorithm outperforms its counterpart considerably by up to 36% and 35% in terms of the average response time and the average task laxity,respectively. 展开更多
关键词 SCHEDULING genetic algorithm REAL-TIME DEADLINE
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Empirical likelihood for single-index models with responses missing at random 被引量:3
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作者 XUE LiuGen LIAN Heng 《Science China Mathematics》 SCIE CSCD 2016年第6期1187-1207,共21页
The missing response problem in single-index models is studied, and a bias-correction method to infer the index coefficients is developed. Two weighted empirical log-likelihood ratios with asymptotic chisquare are der... The missing response problem in single-index models is studied, and a bias-correction method to infer the index coefficients is developed. Two weighted empirical log-likelihood ratios with asymptotic chisquare are derived, and the corresponding empirical likelihood confidence regions for the index coefficients are constructed. In addition, the estimators of the index coefficients and the link function are defined, and their asymptotic normalities are proved. A simulation study is conducted to compare the empirical likelihood and the normal approximation based method in terms of coverage probabilities and average lengths of confidence intervals. A real example illustrates our methods. 展开更多
关键词 single-index model empirical likelihood confidence region index coefficient missing response
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Influence of Temperature Difference Calculation Method on the Evaluation of Rankine Cycle Performance 被引量:1
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作者 Takafumi.Morisaki Yasuyuki.Ikegami 《Journal of Thermal Science》 SCIE EI CAS CSCD 2014年第1期68-76,共9页
In the new century, energy and environmental problems are becoming more critical, and the development of natural energy is desired. Low-grade Thermal Energy Conversion(LTEC) is refocused as one of the renewable energy... In the new century, energy and environmental problems are becoming more critical, and the development of natural energy is desired. Low-grade Thermal Energy Conversion(LTEC) is refocused as one of the renewable energy methods. The usefulness of LTEC is expected using hot springs and waste heat. In the case of the Rankine cycle using ammonia as the working fluid, the thermal properties of the working fluid changes in the evaporator. The traditional evaluation method of heat exchanger performance is the LMTD(Logarithmic Mean Temperature Difference) method. On the other hand, the GMTD(Generalized Mean Temperature Difference) method allows the variation of thermal properties in the heat exchanger. The aim of this study is to compare the two methods for the calculation of temperature differences and the corresponding influence on the total performance of the Rankine cycle that is operated using ammonia as a working fluid. As a result, the thermal efficiency of the Rankine cycle is greater than that of the LMTD method. Moreover, the computable range of the GMTD calculation method is less than that of the LMTD calculation method. 展开更多
关键词 GMTD LMTD LTEC OTEC rankine cycle
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Retinex based low-light image enhancement using guided filtering and variational framework 被引量:5
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作者 张诗 唐贵进 +2 位作者 刘小花 罗苏淮 王大东 《Optoelectronics Letters》 EI 2018年第2期156-160,共5页
A new image enhancement algorithm based on Retinex theory is proposed to solve the problem of bad visual effect of an image in low-light conditions. First, an image is converted from the RGB color space to the HSV col... A new image enhancement algorithm based on Retinex theory is proposed to solve the problem of bad visual effect of an image in low-light conditions. First, an image is converted from the RGB color space to the HSV color space to get the V channel. Next, the illuminations are respectively estimated by the guided filtering and the variational framework on the V channel and combined into a new illumination by average gradient. The new reflectance is calculated using V channel and the new illumination. Then a new V channel obtained by multiplying the new illumination and reflectance is processed with contrast limited adaptive histogram equalization(CLAHE). Finally, the new image in HSV space is converted back to RGB space to obtain the enhanced image. Experimental results show that the proposed method has better subjective quality and objective quality than existing methods. 展开更多
关键词 RGB CLAHE Retinex based low-light image enhancement using guided filtering and variational framework HSV
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Convection in the Rayleigh-Bénard Flow with all Fluid Properties Variable 被引量:1
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作者 Athanasios Sassos Asterios Pantokratoras 《Journal of Thermal Science》 SCIE EI CAS CSCD 2011年第5期454-459,共6页
In the present paper, the effect of variable fluid properties (density, viscosity, thermal conductivity and specific heat) on the convection in the classical Rayleigh-Benard problem is investigated. The investigatio... In the present paper, the effect of variable fluid properties (density, viscosity, thermal conductivity and specific heat) on the convection in the classical Rayleigh-Benard problem is investigated. The investigation concerns water, air, and engine oil by taking into account the variation of fluid properties with temperature. The results are obtained by numerically solving the governing equations, using the SIMPLE algorithm and covering large temperature differences. It is found that the critical Rayleigh number increases as the temperature difference increases considering all fluid properties variable. However, when the fluid properties are kept constant, calculated at the mean temperature, and only density is considered variable, the critical Rayleigh number either decreases or remains constant. 展开更多
关键词 Rayleigh-Benard variable properties ONSET numerical investigation.
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