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Heat transfer characteristics in a narrow confined channel with discrete impingement cooling

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Chinese Journal of Aeronautics 2022年第4期35卷 220-229页

作者： yang LI Tao LIU Jianjun TAO weihua yang Likun DONG Hunan Key Laboratory of Turbomachinery on Small and Medium Aero-Engine AECC Hunan Aviation Powerplant Research InstituteZhuzhou 412002China College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Heat transfer characteristics in a narrow confined channel with discrete impingement cooling were investigated using thermal infrared camera. Detailed heat transfer distributions and comparisons on three surfaces with three impact diameters were experimentally studied in the range of Reynolds number of 3000 to 30000. The experimental results indicated that the strong impingement jet leaded to a high strength heat transfer zone in the ΔX=±2.5D;range of the impact center,which was 1.3–2.5 times of the average heat transfer value of the impingement wall. With the same coolant mass flow rate, small diameter case had lower heat transfer coefficient on both inner wall and outside wall, while the impingement wall was insensitive to the impact diameter. The surface averaged Nusselt number of inner wall was only 43%–57% of impingement wall, while the outside wall can reach up to 80%–90%. The larger the diameter, the higher heat transfer enhancement and the smaller the channel flow resistance was observed in term of Reynolds number. The surface averaged Nusselt numbers were developed as the function of Reynolds number and the impingement height-to-diameter for further engineering applications.

关键词： Aero-engine Heat transfer characteristics Impingement cooling Narrow confined channel Turbine blade

Experimental Investigation on Convective Heat Transfer Characteristics in Ribbed Channel

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Transactions of Nanjing University of Aeronautics and Astronautics 2018年第6期35卷 962-972页

作者： Xie Changtan Xue Shulin yang weihua AEEC Hunan Avation Powerplant Research Institute Zhuzhou 412002P.R.China College of Energy and Power Engineering Nanjing University of Astonautics and AeronauticsNanjing 210016P.R.China

The heat transfer and pressure loss characteristics on a square channel with two opposite surfaces roughened by high blockage ratio ribs are measured by systematic *** numbers studied in the channel range from 1 400 to 8 *** ratios of rib height to hydraulic diameter (e/D) are 0.2and 0.33,*** ratio of rib spacing to height (P/e) ranges from 5to *** rib orientations in the opposite surfaces are symmetrical and staggered *** results show that the heat transfer coefficients are increased with the increase of rib height and Reynolds number,though at the cost of higher pressure *** the rib spacing to height ratio is 10,it keeps the highest heat transfer coefficient in three kinds of rib spacing to height ratios 5,10 and *** heat transfer coefficient of symmetrical arrangement ribs is higher than that of the staggered arrangement ribs,but the pressure loss of the symmetrical arrangement ribs is larger than that of the staggered arrangement ribs.

关键词： convective heat transfer rib channel experimental investigation aeroengine

A survey on book-embedding of planar graphs

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Frontiers of Mathematics in China 2022年第2期17卷 255-273页

作者： Xiaxia GUAN Chuxiong WU weihua yang Jixiang MENG College of Mathematics Taiyuan University of TechnologyTaiyuan 030024China College of Mathematics and System Science Xinjiang UniversityUrumqi 830046China

The book-embedding problem arises in several area,such as very large scale integration(VLSI)design and routing multilayer printed circuit boards(PCBs).It can be used into various practical application fields.A book embedding of a graph G is an embedding of its vertices along the spine of a book,and an embedding of its edges to the pages such that edges embedded on the same page do not *** minimum number of pages in which a graph G can be embedded is called the pagenumber or book-thickness of the graph *** is an important measure of the quality for *** is NP-hard to research the pagenumber of book-embedding for a graph *** paper summarizes the studies on the book-embedding of planar graphs in recent years.

关键词： Book embedding planar graphs pagenumber

HCSP-Net:A Novel Model of Age-Related Macular Degeneration Classification Based on Color Fundus Photography

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Computers, Materials & Continua 2024年第4期79卷 391-407页

作者： Cheng Wan Jiani Zhao Xiangqian Hong weihua yang Shaochong Zhang College of Electronic and Information Engineering/College of Integrated Circuits Nanjing University of Aeronautics and AstronauticsNanjing211106China Shenzhen Eye Institute Shenzhen Eye HospitalJinan UniversityShenzhen518040China

Age-related macular degeneration(AMD)ranks third among the most common causes of *** the most conventional and direct method for identifying AMD,color fundus photography has become prominent owing to its consistency,ease of use,and good quality in extensive clinical *** this study,a convolutional neural network(CSPDarknet53)was combined with a transformer to construct a new hybrid model,*** hybrid model was employed to tri-classify color fundus photography into the normal macula(NM),dry macular degeneration(DMD),and wet macular degeneration(WMD)based on clinical classification manifestations,thus identifying and resolving AMD as early as possible with color fundus *** further enhance the performance of this model,grouped convolution was introduced in this study without significantly increasing the number of ***-Net was validated using an independent test *** average precision of HCSPNet in the diagnosis of AMD was 99.2%,the recall rate was 98.2%,the F1-Score was 98.7%,the PPV(positive predictive value)was 99.2%,and the NPV(negative predictive value)was 99.6%.Moreover,a knowledge distillation approach was also adopted to develop a lightweight student network(SCSP-Net).The experimental results revealed a noteworthy enhancement in the accuracy of SCSP-Net,rising from 94%to 97%,while remarkably reducing the parameter count to a quarter of *** attribute positions SCSP-Net as a highly suitable candidate for the deployment of resource-constrained devices,which may provide ophthalmologists with an efficient tool for diagnosing AMD.

关键词： Computer-aided diagnosis deep learning age-related macular degeneration transformer

Experimental analysis of pore structure and fractal characteristics of soft and hard coals with same coalifcation

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International Journal of Coal Science & Technology 2022年第4期9卷 107-121页

作者： Barkat Ullah Yuanping Cheng Liang Wang weihua yang Izhar Mithal Jiskani Biao Hu School of Safety Engineering China University of Mining and TechnologyXuzhouChina School of Resources and Safety Engineering Central South UniversityChangshaChina NUST Balochistan Campus National University of Sciences and TechnologyQuettaPakistan

Accurate and quantitative investigation of the physical structure and fractal geometry of coal has important theoretical and practical signifcance for coal bed methane(CBM)development and the prevention of dynamic disasters such as coal and gas *** study investigates the pore structure and fractal characteristics of soft and hard coals using nitrogen and carbon dioxide(N_(2)/CO_(2))*** samples from Pingdingshan Mine in Henan province of China were collected and pulverized to the required size(0.20–0.25 mm).N_(2)/CO_(2)adsorption tests were performed to evaluate the specifc surface area(SSA),pore size distribution(PSD),and pore volume(PV)using Braunuer-Emmett-Teller(BET),Barrett-Joyner-Halenda(BJH),and Density Functional Theory(DFT).The pore structure was characterized based on the theory of fractal *** results unveiled that the strength of coal has a signifcant infuence on pore structure and fractal *** are signifcant diferences in SSA and PV between both *** BJH-PV and BET-SSA obtained by N_(2)-adsorption for soft coal are 0.029–0.032 cm^(3)/g and 3.523–4.783 m^(2)/*** the values of PV and SSA obtained by CO_(2)-adsorption are 0.037–0.039 cm^(3)/g and 106.016–111.870 m^(2)/*** coal shows greater SSA and PV than hard coal,which is consistent with the adsorption capacity(VL).The fractal dimensions of soft and hard coal are respectively *** Ding coal exhibits larger D1 and smaller D_(2),and the reverse for the Wu coal seam is *** greater the value of D1(complexity of pore surface)of soft coal is,the larger the pore surface roughness and gas adsorption capacity *** results enable us to conclude that the characterization of pores and fractal dimensions of soft and hard coals is diferent,tending to diferent adsorption/desorption *** this regard,the results provide a reference for formulating corresponding coal and gas outburst prevention and control measures.

关键词： Methane adsorption Soft and hard coal Pore structure Fractal characteristics N_(2)/CO_(2)adsorption

On the design of compensator for quantization-caused input-output deviation

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Science China(Information Sciences) 2011年第4期54卷 824-835页

作者： GUO YuQian,GUI weihua & yang ChunHua School of Information Science and Engineering,Central South University,Changsha 410083,China 1. School of Information Science and Engineering Central South University Changsha 410083 China

This paper considers the design of compensators for systems with quantized inputs in order to reduce the influence of *** systems with (vector) relative degrees,we propose a kind of compensators which can compensate for the accumulated output deviation completely caused by *** proposed compensators are capable of keeping the differences of the input-output responses between the systems with quantized inputs and the original systems without considering quantization within certain small *** show that the compensators in this paper are robust with respect to model uncertainties,disturbance and measurement noise and can significantly improve the input-output responses of systems with both input quantization and packet dropouts.

关键词： networked control systems quantization packet dropout I/O deviation compensation

Energy dissipation and angular momentum transfer within a magnetically torqued accretion disc

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Science China(Physics,Mechanics & Astronomy) 2010年第S1期53卷 106-109页

作者： GAN ZhaoMing,WANG DingXiong,LEI weihua & LI yang School of Physics,Huazhong University of Science and Technology,Wuhan 430074,China 1. School of Physics Huazhong University of Science and Technology Wuhan 430074 China

We discuss transportation and redistribution of energy and angular momentum in the magnetic connection(MC) process and Blandford-Payne(BP) *** results in readjusting the interior viscous torque,and its effects are operative not only in but also beyond the MC *** BP process is invoked to transfer the "excessive" angular momentum from an accretion *** addition,we derive a criterion for the interior viscous torque to resolve the puzzle of the overall equilibrium of angular momentum in disc *** turns out that the efficiency of BP at extracting angular momentum and the intensity of the outflow are required to be greater than some critical values.

关键词： accretion:accretion discs black hole physics magnetic field angular momentum transfer

Establishment of fundus Image Database for Current Artificial Intelligence Research

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Establishment of fundus Image Database for Current Artificia...

松辽盆地双城断陷白垩系营城组四段致密油成藏主控因素及模式

2019年浙江省眼科学学术大会

作者： yang,weihua Wu,Maonian Key Laboratory Of Medical Artificial Intelligence Of Huzhou University

BACKGROUND:Ophthalmology has abundant kinds of imaging data and has become an advantageous subject in the application of intelligent *** image database suitable for current AI research needs to be constructed ***:To e...

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岩性油气藏 2024年第4期36卷 25-34页

作者：杨为华中国石油大庆油田公司采油五厂黑龙江大庆163712

综合利用地震资料和岩心分析测试资料如包裹体均一温度、岩石热解和储层物性等,对松辽盆地双城断陷白垩系营城组四段(营四段)致密油藏类型、分布特征、成藏期次进行了分析,并从烃源岩评价、储层特征、构造活动和输导体系4个方面对致密... 详细信息

综合利用地震资料和岩心分析测试资料如包裹体均一温度、岩石热解和储层物性等,对松辽盆地双城断陷白垩系营城组四段(营四段)致密油藏类型、分布特征、成藏期次进行了分析,并从烃源岩评价、储层特征、构造活动和输导体系4个方面对致密油成藏的主控因素进行了研究。研究结果表明:(1)松辽盆地双城断陷营四段致密油藏的类型及分布规律为,自中部洼槽向两侧斜坡依次发育源内岩性油藏、近源断层-岩性、地层油藏和远源构造油藏,油藏为一期成藏,主成藏期为晚白垩世姚家组沉积末期—嫩江组沉积初期(80~78 Ma)。(2)研究区营四下亚段发育的湖相泥岩、油页岩的生烃潜力较大,中部洼槽为生、排烃中心,生、排烃强度均较高,分别为(20~300)×10^(4)t/km^(2)和(5~53)×10^(4)t/km^(2);营四上亚段发育的扇三角洲相含砾砂岩储层厚度大、连续性好,前缘砂体延伸入湖,平均孔隙度为11.4%,平均渗透率为0.95 mD,其中孔隙度大于8.0%、渗透率高于0.85 mD的相对优质储层是致密油富集的有利目标;深层各类圈闭在早白垩世泉头组沉积末期即已形成,而主成藏期时研究区构造活动较弱,有利于油藏的形成和保存;由断裂、不整合和连通砂体组成的多类型立体输导体系是油气运移主要通道,促进油气向两侧斜坡汇聚。(3)研究区致密油成藏受“源-扇-体”耦合控制,围绕生烃洼槽呈环带状分布,具有大面积分布、局部富集的特点,中部洼槽为源内“源-储叠置、网毯连接、扇体聚集”成藏模式,东部斜坡为近源“源-储紧邻、断-砂匹配、阶梯运移”成藏模式,西部陡坡为远源“源-储分离、‘Y’型运聚、高点富集”成藏模式。被泥岩包裹或与泥岩互层式接触的扇体、油源断裂附近的断层-岩性圈闭和地层圈闭、靠近油源断裂的背斜和断背斜圈闭分别是中部洼槽、东部斜坡和西部斜坡的有利勘探目标。

关键词：深层致密油断陷盆地源内自生自储近源岩性地层油藏远源构造油藏输导体系营城组四段白垩系双城断陷松辽盆地