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THE STRUCTURAL FLOW IN PIPE CONTAINING POROUS MEDIUM SATURATED WITH POWER-LAW FLUID

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Journal of Hydrodynamics 2012年第1期24卷 138-144页

作者： ZHOU Xiao-jun YU Min-chao School of Mechatronics-Engineering and Automation Shanghai UniversityShanghai 200072China

In this article,the method of volume averaging of flow in porous media and averaging theorem was employed to the Navier-Stokes *** total drag force per unit volume was considered as the bulk damping resistance due to the porous structure（i.e.,the Darcy resistance）and the resistance due to the inertia force（i.e.,the Forchheimer resistance）,then the Brinkman-Forchheimer extended Darcy model was obtained from average momentum *** structural flow in a pipe containing porous medium saturated with power law fluid was applied in the present study.A new theoretical analysis of fully developed non-Darcy flow in a pipe containing a fibrous medium saturated with power law fluid was *** the integration method,the boundary layer solutions were obtained for flow core velocity and its *** theoretical solutions were used to analyze the effects of the Darcy number and inertia parameter on the axial velocity profile in the porous medium pipe.

关键词： power-law fluid porous media volume averaging structural flow non-Darcy regime

Model and algorithm of flow interception problem with multi-type of flows

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Journal of Systems Engineering and Electronics 2009年第4期20卷 755-761页

作者： Hu Dandan Yang chao Yang jun Dept. of Management Science and Engineering Huazhong Univ. of Science and Technology Wuhan 430074 P. R. China

To study simultaneous location of different kinds of facilities, a new model of flow interception problem with multi-type of flows is proposed, with the consideration of multi-purpose flows and the influence of facilities on each other. To be more practical, the objective is to maximize the benefits from flow-by customers instead of maximizing flows in the past. Since this problem is NP-hard and there is no optimal solution for large network, greedy and improved greedy heuristic algorithms are proposed. A computational example is presented to show that the optimal location decisions are proved to be strongly dependent on the influence coefficients and average profits by one customer and different types of facilities are almost co-located. Finally the results of sensitivity analysis are reported.

关键词： location flow interception greedy heuristic multi-purpose influence coefficient

Budget constrained flow interception location model for congested systems

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Journal of Systems Engineering and Electronics 2009年第6期20卷 1255-1262页

作者： Hu Dandan Yang chao Yang jun Dept. of Management Science and Engineering Huazhong Univ. of Science and Technology Wuhan 430074 P. R. China

To study location problems with congestion demand, a bi-objective model based on flow intercep-tion problem is *** model is formulated from the view of M/M/m queuing *** quantity and quality are simultaneously considered as objectives, with constraint on total *** quality includes deviation distance from preplanned trips and customers＇ waiting *** quantity is the number of intercep-tion customers.A multi-objective evolutionary algorithm combined with greedy heuristic is *** a computational experiment is given, and the algorithm is proved to be efficient.

关键词： location flow interception bi-objective heuristic.

Co-based Amorphous/Nanocrystalline Composite Coatings Deposited by Arc Ion Plating

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Journal of Materials Science & Technology 2013年第9期29卷 806-812页

作者： Zhengkai Chang jun Gong chao Sun State Key Laboratory for Corrosion and Protection Institute of Metal ResearchChinese Academy of Sciences

Cobalt-based amorphous/nanocrystalline composite coatings have been grown by arc ion plating together with a specimen cooling system. With decreasing substrate temperature, the coatings undergo significant structure evolution. The degree of crystallization first decreases and subsequently increases as confirmed by X-ray diffraction. The cluster size first decreases and then remains constant as confirmed by transmission electron microscopy. The effect of substrate temperature on the evolution of the structure has been studied as a result of a competition between nucleation thermodynamics and kinetics of crystalline growth. With decreasing the substrate temperature, the microhardness and the critical load of the composite coatings firstly increased, and then remained almost constant. And the saturation magnetization revealed the opposite trend over the same range. The essence of these phenomena was ascribed to the microstructural variations caused by the decrease of the substrate temperature.

关键词： Amorphous/nanocrystalline composite coatings Arc ion plating Thermodynamics Kinetics Microhardness Critical load

Temporally Consistent Depth Map Prediction Using Deep Convolutional Neural Network and Spatial-Temporal Conditional Random Field

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Journal of Computer Science & Technology 2017年第3期32卷 443-456页

作者： Xu-Ran Zhao Xun Wang qi-chao Chen School of Computer and Information Engineering Zhejiang Gongshang University Hangzhou 310018 China

Deep convolutional neural networks （DCNNs） based methods recently keep setting new records on the tasks of predicting depth maps from monocular images. When dealing with video-based applications such as 2D （2-dimensional） to 3D （3-dimensional） video conversion, however, these approaches tend to produce temporally inconsistent depth maps, since their CNN models are optimized over single frames. In this paper, we address this problem by introducing a novel spatial-temporal conditional random fields （CRF） model into the DCNN architecture, which is able to enforce temporal consistency between depth map estimations over consecutive video frames. In our approach, temporally consistent superpixel （TSP） is first applied to an image sequence to establish the correspondence of targets in consecutive frames. A DCNN is then used to regress the depth value of each temporal superpixel, followed by a spatial-temporal CRF layer to model the relationship of the estimated depths in both spatial and temporal domains. The parameters in both DCNN and CRF models are jointly optimized with back propagation. Experimental results show that our approach not only is able to significantly enhance the temporal consistency of estimated depth maps over existing single-frame-based approaches, but also improves the depth estimation accuracy in terms of various evaluation metrics.

关键词： depth estimation temporal consistency convolutional neural network conditional random fields

Shear bond strengths between alumina-toughened zirconia cores and veneering ceramics and their susceptibility to aging

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Asian Pacific Journal of Tropical Medicine 2012年第5期5卷 402-405页

作者： Yong-qi Zhao Li Jiang Jing-chao Zhang Yun-Mao Liao jun-jun Lu Wei Li State Key Laboratory of Oral Diseases Sichuan University Hainan Stomatological Hospital

Objective:To evaluate the shear bond strength(SBS) between alumina-toughened zirconia (ATZ) cores and veneering ceramics,investigate the effect of aging in artificial saliva on SBS and compare it with that of yttria-stabilized tetragonal zirconia polycrystals(Y-TZP).Methods:Bars of ATZ and Y-TZP were layered with veneering ceramics in accordance to the recommendation of the *** of each group(n = 10) was aged at 134℃.(under 2 bar pressure) in an autoclave for 48 ***,all specimens were subjected to shear force in a universal testing *** interface and fractured surface of the specimens were evaluated using scanning electron microscopy and X-ray energy dispersive ***:The initial mean SBS values in MPa±SD were 28.9±8.0 for ATZ and 26.2±7.6 for *** aging,the mean SBS values for ATZ and Y-TZP were 22.9±4.9 MPa and 22.8±6.9 MPa,*** the differences between the SBS values of the ATZ and Y-TZP groups nor the influence of aging on all groups were statistically ***:The SBS between the ATZ core and the veneering ceramics was not affected by *** SBS of ATZ to veneering ceramics was not significantly different compared with that of Y-TZP.

关键词： Shear bond strength Zirconia Alumina Veneering ceramics Aging

The Effect of Heating Direction on Flow Boiling Heat Transfer of R134a in Microchannels

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Journal of Thermal Science 2017年第2期26卷 166-174页

作者： XU Mingchen JIA Li DANG chao PENG qi Institute of Thermal Engineering School of MechanicalElectronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Beijing Key Laboratory of Flow and Heat Transfer of Phase Changing in Micro and Small Scale Beijing 100044China

This paper presents effects of heating directions on heat transfer performance of R134 a flow boiling in micro-channel heat sink. The heat sink has 30 parallel rectangular channels with cross-sectional dimensions of 500mm width 500mm depth and 30 mm length. The experimental operation condition ranges of the heat flux and the mass flux were 13.48 to 82.25 W/cm^2 and 373.3 to 1244.4 kg/m^2 s respectively. The vapor quality ranged from 0.07 to 0.93. The heat transfer coefficients of top heating and bottom heating both were up to 25 k W/m^2 K. Two dominate transfer mechanisms of nucleate boiling and convection boiling were observed according to boiling curves. The experimental results indicated that the heat transfer coefficient of bottom heating was 13.9% higher than top heating in low heat flux, while in high heat flux, the heat transfer coefficient of bottom heating was 9.9%.higher than the top heating, because bubbles were harder to divorce the heating wall. And a modified correlation was provided to predict heat transfer of top heating.

关键词： top heating bottom heating flow boiling micro-channels R134a correlation

Visualization Investigation on Flowing Condensation in Horizontal Small Channels with Liquid Separator

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Journal of Thermal Science 2018年第1期27卷 48-54页

作者： ZHANG Xuan JIA Li DANG chao PENG qi Institude of Thermal Engineering School of MechanicalElectronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Beijing key laboratory of flow and heat transfer of phase changing in micro and small scale Beijing 100044China

A simultaneous visualization and measurement experiment was carried out to investigate condensation flow pat- terns and condensing heat transfer characteristics of refrigerant R14 lb in parallel horizontal multi-channels with liquid-vapor separator. The hydraulic diameter of each channel was 1.5 mm and the channel length was 100 ram. The refrigerant vapor flowing in the small channels was cooled by cooling water. The parallel horizontal mul- ti-channels were covered with a transparent silica glass for visualization of flow patterns. Experiments were per- formed at different inlet superheat temperatures （ranging from 3~C to 7~C）. Mass velocity was in the range of 82.37 kg mZs1 to 35.56 kg m-2s1. It was found that there were three different flow patterns through the mul- ti-channels with the increase of mass velocity. The flow patterns in each channel pass almost tended to be same and all of them were annular flows.＇ The efficiency of the liquid-vapor separator with U-type was related to vapor mass velocity and the pressure in the small channels. It was also found that the heat transfer coefficient increased with the increase of the mass velocity while the cooling water mass flow rate increased. It increased to a top point and then decreased. It increased with the increase of superheat in the low superheat temperature region.

关键词： condensation visualization multi-channels liquid-vapor separation

Estrogenic effects of water from the Yangtze River (Nanjing section) on goldfish (Carassius auratus) after an early life stage exposure

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Journal of Environmental Sciences 2011年第7期23卷 1179-1185页

作者： Wenting Song Guanghua Lu Pengde qi chao Wang Key Laboratory for Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education College of Environment Hohai University Nanjing 210098 China School of Physics and Chemistry Henan Polytechnic University Jiaozuo 454000 China

Effects of river water from the Yangtze River （Nanjing section） on fish development, vitellogenin （VTG） induction, gonado-somatic index （GSI） and sex ratio were investigated by exposing goldfish （Carassius auratus） in the early life stage （from fertilization to 28 days post-hatch） to water samples （25%, 50% and 100%） collected from three representative sections. The results showed that there was no significant effect on hatching success for any of the exposure groups, but survival was significantly reduced when compared with the control （P 0.05）. Body lengths, weights of all treated fish did not differ significantly from those of the control. Condition factors （CF） of larval fish exposed to 50% and 100% river water from the Jiangxinzhou section and 100% river water from the Daqiao section were significantly lower than that of the control （P 0.05）. VTG inductions were significant in larval fish exposed to all the dilution series of river water. No significant difference in CF value was observed in any exposure group after 150 days of depuration. VTG was fully eliminated after 75 days of depuration. For both female and male, GSI did not significantly differ between exposure groups and the control after 150 days of convalescence. The highest female：male ratios were observed in response to the treatment with 50% or 100% river water from the Jiangxinzhou section and 100% river water from the Daqiao section （53：47, 56：44 and 54：46, respectively）, but no significant difference in sex ratio was observed in any treated group when compared to the control. The results showed that early life stage exposure of river water from the Yangtze River （Nanjing section） had adverse effects on goldfish development and reproductive health, and the effects on CF and VTG were reversible after depuration in clean water.

关键词： the Yangtze River estrogenic effects goldfish early life stage exposure