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Heat Transfer Coefficient of Film Cooling with Ellipse-Shaped Tab

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Transactions of Nanjing University of Aeronautics and Astronautics 2016年第2期33卷 155-165页

作者： Zheng Xianwu yang weihua China Aviation Powerplant Research Institute Zhuzhou 412002 P. R. China College of Energy and Power Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 P.R. China

The enhanced cooling performance caused by ellipse-shaped tabs located at the outlet of the film cooling holes is *** covering ratios of ellipse-shaped tabs on film holes and four blowing ratios are *** results show that:(1)The heat transfer coefficient ratio is higher than that without tab,indicating that the mixing of mainstream and coolant jet provides a better coverage film on the cooling wall,but increases the local turbulence production which enhances the heat transfer coefficient;(2)When the ellipse-shaped tabs are located at the film hole outlet,there is a larger pressure drop with the ellipse tab relative to the no-tab ***,the discharge coefficient with ellipse tab is lower than that without tab.

关键词： energy and power engineering turbine machine ellipse-shaped tab film cooling

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

外泌体在糖尿病视网膜病变诊断和治疗中的研究进展

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国际眼科杂志 2025年第2期25卷 235-241页

作者：董松果宋春艳侯小凤杨卫华王云中国广东省深圳市眼科医院、深圳市眼病防治研究所 518033

外泌体在各类体液中普遍存在,且含量丰富种类多样。因其特殊的结构、功能参与了细胞间通讯、物质运输、免疫调节等生命活动。越来越多的研究发现外泌体中有诊断糖尿病视网膜病变的标志物,也是治疗糖尿病视网膜病变新的突破口,具有良好... 详细信息

外泌体在各类体液中普遍存在,且含量丰富种类多样。因其特殊的结构、功能参与了细胞间通讯、物质运输、免疫调节等生命活动。越来越多的研究发现外泌体中有诊断糖尿病视网膜病变的标志物,也是治疗糖尿病视网膜病变新的突破口,具有良好的临床应用前景。文章基于外泌体的生物学功能,探究糖尿病视网膜病变中外泌体的诊断和治疗机制,总结外泌体在糖尿病视网膜病变诊断和治疗研究中的进展,实现对糖尿病视网膜病变更有效的临床诊断和治疗。

关键词：外泌体生物学功能糖尿病视网膜病变诊断和治疗

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

有机磷农药污染地块有机物质组成特征与异味物质识别

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环境化学 2025年第1期44卷 164-173页

作者：翟增秀李伟芳李佳音杨伟华肖咸德王静天津市生态环境科学研究院天津300191 国家环境保护恶臭污染控制重点实验室天津300191 天津迪兰奥特环保科技开发有限公司天津300191

农药污染地块异味问题凸显,准确识别异味物质是地块治理修复的重要科学依据.采用顶空-气相色谱高分辨质谱法对有机磷农药污染地块土壤中的挥发性及半挥发性有机物进行检测,综合检出物质的嗅觉阈值、浓度水平、检出率及挥发性等4个指标,... 详细信息

农药污染地块异味问题凸显,准确识别异味物质是地块治理修复的重要科学依据.采用顶空-气相色谱高分辨质谱法对有机磷农药污染地块土壤中的挥发性及半挥发性有机物进行检测,综合检出物质的嗅觉阈值、浓度水平、检出率及挥发性等4个指标,通过综合评分法进行异味物质筛选,并结合异味物质的气味安全等级提出有机磷农药污染地块优控异味物质.结果表明,有机磷农药污染地块共检出有机污染物354种,其中以烷烯烃、苯系物、卤代烃、含氧有机物以及硫化物为主(占比之和在90%以上).通过综合评分法筛选出47种潜在异味物质,包括10种含氧有机物、9种含硫有机物、16种芳香化合物、9种卤代烃、2种含氮化合物和1种其他物质(O,O,O-三乙基硫代磷酸酯).根据47种潜在异味物质气味安全等级评价结果,将气味安全等级为A级的8种物质(乙硫醇、三甲胺、戊醛、四氢呋喃、乙醛、甲硫醇、异丙苯和甲硫醚)列为有机磷污染地块优先控制异味物质.

关键词：有机磷农药污染地块有机污染物异味物质筛选.

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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 School of Information Science and Engineering Central South University Changsha 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