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Aerodynamic Optimization and Flow Mechanism for a Compressor Cascade at Low Reynolds Number

Journal of Thermal Science 2025年第1期34卷 92-109页

作者： LI Lin zhang Jianshe CHEN Caiyan TAN Wei zhang yanfeng Key Laboratory of Light-Duty Gas-Turbine Institute of Engineering ThermophysicsChinese Academy of Sciences University of Chinese Academy of Sciences National Key Laboratory of Science and Technology on Advanced Light-duty Gas-turbine

Low-Reynolds-number effect is an important factor affecting the performance of compressors and other main components of high-altitude long-endurance unmanned aerial *** improve the flow condition and reduce flow loss under the condition of high altitude and low Reynolds number(Re),this paper proposes an optimization process based on a surrogate model,which combines the class-shape transformation method(CST),the Latin hypercube sampling(LHS) method,the light gradient-boosting machine algorithm(LightGBM),and a genetic algorithm(GA) to optimize a high-subsonic compressor *** surrogate model is verified to be accurate and can be used in the optimization *** accuracy of the GA is higher than the other algorithms under common test *** optimization results are verified by numerical simulation,and the flow differences before and after optimization are compared,especially the flow within the boundary *** changing the blade shape,the optimization process adjusts the loading distribution to delay the transition of the optimized blade on the suction surface,which changes the turbulent reattachment in the laminar separation bubble(LSB) into laminar ***,the mixing loss induced by the turbulent reattachment of the LSB and the wake loss of turbulent separation at the trailing edge are significantly reduced,and the performance of the compressor profile is finally *** addition,turbulent separation of the optimized profile is delayed reducing the range of the wake region on the suction *** this optimization process,the reduction of total pressure loss coefficient at Re of 2.5×10～5,3.5×10～5,and 4.5×10～5 are 16.32%,20.76%,and 22.16%,respectively.

关键词： Reynolds number

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Reversing free-electron transfer of sulfide cocatalyst for exceptional photocatalytic H_(2)evolution

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Journal of Materials Science & Technology 2024年第4期171卷 147-149页

作者： yanfeng zhang Zhenyi zhang National Experimental Chemistry Teaching Center Hebei Key Laboratory of Inorganic Nano-materialsCollege of Chemistry and Materials ScienceHebei Normal UniversityShijiazhuang 050024China Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission Key Laboratory of Photosensitive Materials and Devices of Liaoning ProvinceSchool of Physics and Materials EngineeringDalian Minzu UniversityDalian 116600China

Recently,Yu and co-workers deeply explore the potential impact of free electron transfer between co-catalysts and photocatalyst carriers on H_(2)evolution efficiency of active sites over MoS_(2+x).They pro-pose an electron-reversal tactics to evade the unexpected electron transfer and synchronously regulate the above transfer in a beneficial orientation for weakening hydrogen adsorption on S ***,this highlight not only discusses and summarizes the essences of electron reversal and the optimized H ad-sorption/desorption mechanism,but also emphasizes the significance of femtosecond transient absorp-tion spectroscopy(fs-TAS)and in-situ irradiated X-ray photoelectron spectroscopy(ISI-XPS)for revealing charge transfer dynamics and *** anticipate that this highlight can disseminate a new per-spective on the roles of photocatalyst carriers in improving cocatalytic H_(2)-production kinetics.

关键词： Photocatalysis Cocatalyst Electron reversal Antibonding-orbital occupancy S–H bonds

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长链非编码RNA核富集转录本1对瘢痕成纤维细胞增殖、凋亡和迁移的影响

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中国组织工程研究 2025年第2期29卷 347-354页

作者：张彦峰张慧敏何翔郑屿萍上海中医药大学附属曙光医院皮肤科上海市201203

背景:已有研究阐明核富集转录本1(nuclear enriched abundant transcript 1,NEAT1)下调抑制了瘢痕成纤维细胞的进展,但具体机制尚不完全清楚。目的:探讨长链非编码RNA NEAT1调节miR-136-5p/泛素特异性蛋白酶4(ubiquitin specific protease 4,USP4)轴对瘢痕成纤维细胞生物学行为的影响。方法:将瘢痕成纤维细胞分为5组:si-NC组、空白对照组、si-NEAT1组、si-NEAT1+miR-136-5p inhibitor组、si-NEAT1+inhibitor-NC组,qRT-PCR检测NEAT1、miR-136-5p表达;CCK-8法及EDU染色检测细胞增殖能力;流式细胞术检测细胞凋亡情况;划痕愈合实验检测细胞迁移情况;Western blot检测USP4、p27、Bax、基质金属蛋白酶9、α-平滑肌肌动蛋白、Ⅰ型胶原蛋白α1链蛋白表达;双荧光素酶实验检测NEAT1与miR-136-5p、miR-136-5p与USP4的关系。结果与结论:①与si-NC组比较,si-NEAT1组NEAT1表达、A450值、EDU阳性细胞百分比、划痕愈合率以及USP4、基质金属蛋白酶9、α-平滑肌肌动蛋白、Ⅰ型胶原蛋白α1链蛋白表达降低(P<0.05),miR-136-5p表达、细胞凋亡率及p27、Bax蛋白表达升高(P<0.05);②miR-136-5p inhibitor逆转了沉默NEAT1对瘢痕成纤维细胞生物学行为的影响;③miR-136-5p与NEAT1、miR-136-5p与USP4存在靶向调控关系。结果表明,沉默NEAT1可能通过调控miR-136-5p/USP4轴抑制瘢痕成纤维细胞的增殖和迁移,诱导其凋亡。

关键词：长链非编码RNA核富集转录本1 miR-136-5p 泛素特异性蛋白酶4 瘢痕成纤维细胞增殖

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Unsteady wakes-secondary flow interactions in a high-lift low-pressure turbine cascade

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Chinese Journal of Aeronautics 2020年第3期33卷 879-892页

作者： Xiao QU yanfeng zhang Xingen LU Junqiang ZHU Key Laboratory of Light-Duty Gas-Turbine Institute of Engineering ThermophysicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100190China

Detailed experimental measurements were conducted to study the interactions between incoming wakes and endwall secondary flow in a high-lift Low-Pressure Turbine(LPT)*** of the measurements were conducted in both the presence and absence of incoming wakes,and numerical analysis was performed to elucidate the flow *** increasing Reynolds number,the influence of the incoming wakes on suppressing the secondary flow gradually increased owing to the greater influence of incoming wakes on reducing the negative incidence angle at higher Reynolds numbers,leading to a lower blade loading near the leading edge and suppression of the Pressure Side(PS)leg of the horseshoe ***,the effect of unsteady wakes on suppressing the profile losses gradually became weaker owing to the reduced size of the Suction Side(SS)separation bubble and increased mixing loss in the free-flow region at high Reynolds *** wakes clearly improved the aerodynamic performance of the low-pressure turbine cascade at low Reynolds numbers of 25,000 and 50,*** contrast,at the high Reynolds number of 100,000,the profile loss at the midspan and mass-averaged total losses downstream of the cascade were higher in the presence of wakes than in the absence of wakes,and the unsteady wakes exerted a negative influence on the aerodynamic performance of the LPT cascade.

关键词： Experimental study High-lift Incoming wakes Low-pressure turbine Secondary flow

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Unsteady experimental and numerical investigation of aerodynamic performance in ultra-high-lift LPT

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Chinese Journal of Aeronautics 2020年第5期33卷 1421-1432页

作者： Xiao QU yanfeng zhang Xingen LU Junqiang ZHU Key Laboratory of Light-Duty Gas-Turbine Institute of Engineering ThermophysicsChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100190China

Detailed experimental and numerical investigations were performed for an ultra-high-lift front-loaded low-pressure turbine cascade (Zw=1.58) with periodic *** interaction mechanisms between the incoming wakes and endwall secondary flow were carefully *** were produced by moving upstream rods,and flow field downstream of the cascade was measured using a seven-hole *** results revealed that incoming wakes influenced not only the boundary layer development of the blade suction surface but also the complex endwall secondary vortex *** the suction surface:Incoming wakes clearly suppressed the suction side separation bubble at a low Reynolds number of ***,the effects of different wake passing frequencies were not significantly different at Re=100000,and the profile losses under wake passing were even greater than in the absence of *** the end walls:Incoming wakes more strongly suppressed secondary flow at Re=100000 than at Re=25000,because the lowmomentum fluid inside the incoming wakes clearly increased the endwall cross-passage pressure gradient at Re=*** experimental results indicated that periodic wakes decreased the passage vortex and counter vortex core strength by 25% and 30%,respectively,at Re=*** results also demonstrated that endwall secondary vortices decreased significantly near the position of wakes passing.

关键词： Experimental investigation Low pressure turbine Periodic wake Secondary flow Ultra-High-lift

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Peak identification for ChIP-seq data with no controls

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Zoological Research 2012年第S3期33卷 121-128页

作者： yanfeng zhang Bing SU State Key Laboratory of Genetic Resources and Evolution Kunming Institute of Zoologythe Chinese Academy of SciencesKunming 650223China

Chromatin immunoprecipitation followed by sequencing(ChIP-seq)is increasingly being used for genome-wide profiling of transcriptional regulation,as this technique enables dissection of the gene regulatory *** input as control,a variety of statistical methods have been proposed for identifying the enriched regions in the genome,i.e.,the transcriptional factor binding sites and chromatin ***,when there are no controls,whether peak calling is still reliable awaits systematic *** address this question,we used a Bayesian framework approach to show the effectiveness of peak calling without controls(PCWC).Using several different types of ChIP-seq data,we demonstrated the relatively high accuracy of PCWC with less than a 5%false discovery rate(FDR).Compared with previously published methods,e.g.,the model-based analysis of ChIP-seq(MACS),PCWC is reliable with lower ***,to interpret the biological significance of the called peaks,in combination with microarray gene expression data,gene ontology annotation and subsequent motif discovery,our results indicate PCWC possesses a high ***,using in silico data,only a small number of peaks were identified,suggesting the significantly low FDR for PCWC.

关键词： ChIP-seq Bayesian Peak calling Gene regulation

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Anisotropic monolayer of ReX_(2)on Au foils for exploring abnormal growth behavior and electronic properties

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Nano Research 2023年第3期16卷 4197-4210页

作者： Wenzhi Quan Shuangyuan Pan Fan Zhou yanfeng zhang Academy for Advanced Interdisciplinary Studies Peking UniversityBeijing 100871China School of Materials Science and Engineering Peking UniversityBeijing 100871China

As an emerging class of semiconducting transition metal dichalcogenides(TMDCs),two-dimensional(2D)rhenium dichalcogenides(ReX_(2),X=S or Se)have recently aroused great research interest due to their unique anisotropic structure(1T′phase),and the related novel properties and ***,many efforts have been devoted to the controllable syntheses of high-quality monolayer or few-layer ReX_(2)flakes/films by chemical vapor deposition(CVD),wherein the metallic Au foil is found to be a unique substrate,due to the relatively strong interfacial coupling between monolayer ReX_(2)and *** the conductive nature of Au enables in situ characterizations of the as-grown ReX_(2)samples,which is essential for exploring the fundamental properties and internal growth ***,this review focuses on the recent progresses on the CVD syntheses and in situ characterizations of high-quality monolayer ReX_(2)flakes/films and their heterostructures with graphene on Au *** effects of Au foils on improving the crystal quality and inducing the growth of monolayer ReX_(2)single crystals are intensively *** crystallinity,domain morphology,atomic and electronic structures,as well as the growth behaviors of monolayer ReX_(2)flakes/films and graphene/ReX_(2)heterostructures on Au revealed by in situ characterization techniques are also *** contrasts,the growth behaviors of monolayer or few-layer ReX_(2)on insulating substrates are also ***,the potential applications of 2D ReX_(2)in new-generation electronic,optoelectronic devices,and energy-related fields are also ***,future research directions are also prospected for propelling the practical applications of 2D ReX_(2)materials in more versatile fields.

关键词： rhenium dichalcogenides(ReX_(2)) Au chemical vapor deposition scanning tunneling microscopy/spectroscopy growth behavior electronic properties

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Flow mechanism between purge flow and mainstream in different turbine rim seal configurations

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Chinese Journal of Aeronautics 2020年第8期33卷 2162-2175页

作者： Ziqing zhang Yingjie zhang Xu DONG Xiao QU Xingen LU yanfeng zhang Key Laboratory of Light-duty Gas-turbine Institute of Engineering ThermophysicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

The rim seal is used to prevent mainstream ingestion to the gap between the vane of a turbine and its blade. In this article, the dolphin lip with a hook configuration and a large seal cavity with hook structures are designed based on the high-pressure turbine datum single shark lip rim seal configuration. The sealing effect and parameters of the flow field are measured by an experiment method and a numerical simulation is used to explain the mechanism. For three configurations,the effect of the leakage slot vortex on the efficiency of the seal and the influence of leakage vortex,generated by the interaction between purge flow and mainstream flow, are discussed in depth. The result shows that the reverse vortex formed by the dolphin lip rim seal with hook structure will increase the sealing efficiency. The seal configuration with a large cavity improves sealing efficiency to a greater extent than the datum structure. At different purge flow rates and with unequal seal structures, the purge flow produces three types of leakage vortices in the passage. Besides, the seal configuration with dolphin lip produces a Kelvin-Helmholtz instability at the interface of the purge and the mainstream flows at a low purge flow rate to induce new leakage vortex branches in the passage of the blade.

关键词： Kelvin-Helmholtz instability Loss of fluid Rim seal Sealing efficiency Turbine Vortex flow

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现象图析学视角下健康焦虑与信息搜寻行为的交互机理研究

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科技情报研究 2025年第1期7卷 75-85页

作者：张艳丰余忞谦湘潭大学公共管理学院湘潭411105

[目的/意义]探析健康焦虑与信息搜寻行为的影响因素与交互机理,有助于丰富信息行为研究的理论范式,为深入解析用户健康焦虑现象提供理论指导与实践应用。[方法/过程]利用现象图析学的质性研究方法,对健康焦虑与信息搜寻行为的交互机理... 详细信息

[目的/意义]探析健康焦虑与信息搜寻行为的影响因素与交互机理,有助于丰富信息行为研究的理论范式,为深入解析用户健康焦虑现象提供理论指导与实践应用。[方法/过程]利用现象图析学的质性研究方法,对健康焦虑与信息搜寻行为的交互机理进行深入挖掘,基于I-PACE理论模型框架,从“用户-情感-认知-行为”4个维度,对用户健康焦虑与信息搜寻行为进行模型要素解析,构建健康焦虑与信息搜寻行为机理关系模型。[结果/结论]研究结果揭示了健康焦虑与信息搜寻行为的交互机理可分为情绪触发、浏览调节、认知控制、行为反馈4个子机理,进而基于研究提出健康焦虑情境下公众信息素养培育策略。

关键词：现象图析学健康焦虑信息搜寻行为交互机理

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Numerical Investigation of the Unsteady Tip Leakage Flow and Rotating Stall Inception in a Transonic Compressor

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Journal of Thermal Science 2010年第4期19卷 310-317页

作者： yanfeng zhang Xingen Lu Wuli Chu Junqiang Zhu School of Power and Energy Northwestern Polytechnical University Xi'an Shaanxi 710072 China Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing 100190 China

It is well known that tip leakage flow has a strong effect on the compressor performance and stability. This paper reports on a numerical investigation of detailed flow structures in an isolated transonic compressor rotor-NASA Rotor 37 at near stall and stalled conditions aimed at improving understanding of changes in 3D tip leakage flow structures with rotating stall *** and unsteady 3D Navier-Stokes analyses were conducted to investigate flow structures in the same *** steady analysis,the predicted results agree well with the experimental data for the estimation of compressor rotor global *** unsteady flow analysis, the unsteady flow nature caused by the breakdown of the tip leakage vortex in blade tip region in the transonic compressor rotor at near stall condition has been captured with a single blade *** the other hand, the time-accurate unsteady computations of multi-blade passage at near stall condition indicate that the unsteady breakdown of the tip leakage vortex triggered the short length-scale-spike type rotating stall inception at blade tip *** was the forward spillage of the tip leakage flow at blade leading edge resulting in the spike stall inception. As the mass flow ratio is decreased,the rotating stall cell was further developed in the blade passage.

关键词： transonic axial-flow compressor tip clearance flow stall inception unsteadiness

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