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Parametric analyses for synthetic jet control on separation and stall over rotor airfoil

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Chinese Journal of Aeronautics 2014年第5期27卷 1051-1061页

作者： zhao Guoqing zhao Qijun National Key Laboratory of Rotorcraft Aeromechanics Nanjing University of Aeronautics and Astronautics

Numerical simulations are performed to investigate the effects of synthetic jet control on separation and stall over rotor airfoils. The preconditioned and unsteady Reynolds-averaged Navier–Stokes equations coupled with a k x shear stream transport turbulence model are employed to accomplish the flowfield simulation of rotor airfoils under jet control. Additionally,a velocity boundary condition modeled by a sinusoidal function is developed to fulfill the perturbation effect of periodic jets. The validity of the present CFD procedure is evaluated by the simulated results of an isolated synthetic jet and the jet control case for airfoil NACA0015. Then, parametric analyses are conducted specifically for an OA213 rotor airfoil to investigate the effects of jet parameters（forcing frequency, jet location and momentum coefficient, jet direction, and distribution of jet arrays） on the control effect of the aerodynamic characteristics of a rotor airfoil. Preliminary results indicate that the efficiency of jet control can be improved with specific frequencies（the best lift-drag ratio at F＋= 2.0） and jet angles（40 or 75） when the jets are located near the separation point of the rotor airfoil. Furthermore, as a result of a suitable combination of jet arrays, the lift coefficient of the airfoil can be improved by nearly 100%, and the corresponding drag coefficient decreased by26.5% in comparison with the single point control case.

关键词： Flow control Flow separation Parametric analysis Rotor Synthetic jet

Surface modification of die casting mold steel by a composite technique of hot-dipping and plasma electrolytic oxidation

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Rare Metals 2012年第4期31卷 362-367页

作者： zhao, Guohua zhao, Jianhua College of Materials Science and Engineering Chongqing UniversityChongqing 400045China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400045China

The hot dipping process of pure aluminum on H13 steel substrates followed by plasma electrolytic oxidation(PEO) was studied to form alumina ceramic coatings for protective purpose.H13 steel bars were first dipped in pure aluminum melts,and then,a reactive iron-aluminum intermetallic layer grew at the interface between the melt and the steel *** reactive layer was mainly composed of intermetallic Fe-Al(Fe_2Al_5);the thickness of aluminum layer and Fe-Al intermetallic layer were mainly influenced by dipping time(1.5～12.0 min) and dipping temperature(710～760 ℃).After PEO process,uniform Al_2O_3 ceramic coatings were deposited on the surface of aluminized *** element distribution,phase composition and morphology of the aluminized layer,and the ceramic coatings were characterized by SEM/EDS and *** distribution of hardness across the composite coating is demonstrated,and the maximum value reaches 1864 *** thermal shock resistance of the coated sample is also well improved.

关键词： plasma electrolytic oxidation hot-dipping aluminum surface modification

Exit options sustain altruistic punishment and decrease the second-order free-riders, but it is not a panacea

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Science China(Information Sciences) 2025年第1期 278-291页

作者： Chen SHEN zhao SONG Lei SHI Jun TANIMOTO Zhen WANG Faculty of Engineering Sciences Kyushu University School of Statistics and Mathematics Yunnan University of Finance and Economics School of Computing Engineering and Digital Technologies Teesside University School of Artificial Intelligence OPtics and Electro Nics (iOPEN) Northwestern Polytechnical University

Why do humans punish free riders at their own expense? This behavior represents an evolutionary puzzle in human societies. This study explores the role of exit strategies in fostering altruistic punishment within evolutionary game theory. We extend the traditional prisoner's dilemma model by incorporating exiters, players who opt out for a small payoff while nullifying their opponent's payoff, and altruistic punishers who cooperate and punish non-cooperators. Our findings indicate that in well-mixed populations, exiters destabilize defection but do not promote altruistic punishment. In social networks, however,exiters enable altruistic punishment via cyclic dominance among altruistic punishers, defectors, and exiters. Notably, this cyclic dominance is sensitive to exit payoffs; adjustments can lead to cyclic dominance of non-punishing cooperators, defectors, and exiters, or to a bi-stable state between these two types of cyclic dominance. These results highlight the nuanced impact of exiters on altruistic punishment, emphasizing the need for careful incentivization of exit behavior. While exiters can support altruistic punishment in networked populations, their effectiveness is not a panacea and is highly sensitive to exit payoffs, indicating limits to the voluntary participation mechanism.

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肾外夹角对外生型肾乏脂肪血管平滑肌脂肪瘤与肾透明细胞癌的鉴别诊断价值

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临床放射学杂志 2025年第1期44卷 133-137页

作者：张小梅李娜赵艳王滔乐山市人民医院放射医学科 614000

目的探讨肾外夹角对外生型肾乏脂肪血管平滑肌脂肪瘤(AMLmf)与肾透明细胞癌(ccRCC)的鉴别诊断价值。方法回顾性分析经手术和病理证实的ccRCC患者55例共56个病灶,AMLmf患者20例共22个病灶,通过形态学分析两组肿瘤差异,测量肿瘤的肾外夹... 详细信息

目的探讨肾外夹角对外生型肾乏脂肪血管平滑肌脂肪瘤(AMLmf)与肾透明细胞癌(ccRCC)的鉴别诊断价值。方法回顾性分析经手术和病理证实的ccRCC患者55例共56个病灶,AMLmf患者20例共22个病灶,通过形态学分析两组肿瘤差异,测量肿瘤的肾外夹角并定量分析两组间的差异。结果假包膜、劈裂征及“冰激凌蛋筒征”对AMLmf与ccRCC的鉴别有统计学差异(P<0.05);两组肿瘤的肾外较大夹角及较小夹角值间差异有统计学意义。受试者工作特征(ROC)曲线分析显示肾外较大夹角、肾外较小夹角、劈裂征、“冰激凌蛋筒征”及假包膜鉴别AMLmf与ccRCC的曲线下面积(AUC)值分别为0.925、0.983、0.638、0.727、0.731,五种指标联合的AUC值为0.996,明显高于单一指标。结论肾外夹角、假包膜、劈裂征及“冰激凌蛋筒征”有助于AMLmf与ccRCC的鉴别诊断,联合五种影像学特征的诊断效能更高。

关键词：体层摄影术 X线计算机肾外夹角肾乏脂肪血管平滑肌脂肪瘤肾透明细胞癌

Fatigue Strength Analysis of Dissimilar Aluminum Alloy TIG Welds

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Journal of Wuhan University of Technology(Materials Science) 2025年第1期 265-274页

作者：廖祥雲王瑞杰 LIU Guoshou zhao Pinglin Faculty of Mechanical and Electrical Engineering Kunming University of Science and Technology Faculty of Civil Engineering and Mechanics Kunming University of Science and Technology

The constant amplitude loading fatigue tests were carried out on the 6061/7075 aluminum alloy TIG fillet welded lap specimens in this study,and the weld seam cross-section hardness was *** experimental results show that most specimens mainly failed at the 7075 side weld toes even though the base material tensile strength of 7075 is higher than that of *** maximum stress-strain concentration in the two finite element models is located at the 7075 side weld toe,which is basically consistent with the actual fracture *** weld zone on the 7075 side experiences severe material softening,with a large ***,the Vickers hardness value on the 6061 side negligibly changes and fluctuates around 70 *** obvious defects are found on the fatigue fracture,but a large number of secondary cracks *** germinate from the weld toe and propagate in the direction of the plate *** reinforcement has a serious impact on fatigue *** life will decrease exponentially as the weld reinforcement increases under low *** is found that the notch stress method can give a better fatigue life prediction for TIG weldments,and the errors of the predicted results are within the range of two factors,while the prediction accuracy decreases under low *** equivalent structural stress method can also be used for fatigue life prediction of TIG weldments,but the errors of prediction results are within the range of three factors,and the accuracy decreases under high stress.

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Gradient maturation experiment on hairs implies taphonomic changes in fossil hairs

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Science China Earth Sciences 2025年第1期 62-73页

作者： Xin LI Yibo ZHOU Tao zhao Xingjian HE Yanhong PAN State Key Laboratory for Mineral Deposits Research Center for Critical Earth Material Cycling Centre for Research and Education on Biological Evolution and Environment and Frontiers Science School of Earth Sciences and Engineering Nanjing University Institute of Palaeontology Yunnan Key Laboratory of Earth System Science Yunnan Key Laboratory for PalaeobiologyYunnan University

Mammalian hair, as a key feature related to endothermy, physical protection, and camouflage, has a long geohistorical record that dates back even to the Mesozoic. However, the limited information on the taphonomy of hair hinders the understanding of its evolutionary significance in deep time. To address this, we conducted taphonomic experiments to simulate the transformation process of black hair. The changes in the morphological structure, microscopic characteristics, and chemical composition of hair during the simulated fossilization process were documented by scanning electron microscopy, Fourier transform infrared(FTIR) spectroscopy, and Raman spectroscopy. Our results revealed that damage to the morphology of hair began at a mild temperature(150–175°C), and hair transformed into a fluid-like mass at a relatively high temperature(200°C). In addition, the morphological structure of melanosomes had relatively greater preservation potential than keratins did, and the microscopic features of melanosomes were persistently stable. The Raman and FTIR spectra indicated that the characteristic melanin and keratin peaks changed as the temperature increased. Although the chemical signals were not lost completely, the variations in the characteristic amide bands in the FTIR spectra indicate that the keratins severely degraded at high temperatures(>200°C), whereas the characteristic melanin bands in the Raman spectra suggested that melanin signals were still recognizable, even at high temperatures(>200°C). These results were confirmed by principal component analysis(PCA) and principal component analysis linear discriminant analysis(PCA–LDA). In addition, the Raman signals of all the samples in the simulated experiments were distinguished from the signals of common geological carbonaceous materials(humic acid), which suggested that Raman spectroscopy can be used to detect melanin in fossils.

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Nanoprobes in biomedical detection

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Science China Chemistry 2016年第3期59卷 255-263页

作者： Yawei zhao Changling Zou Hongkang zhao Lina zhao School of Physics Beijing Institute of Technology Beijing 100081 China Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China

Environmental problems caused by the development of nanotechnology have threatened human health. Investigating the biomedical effects of nanomaterials can help to solve these environmental safety issues. In studies on the biomedical effects of nanomaterials, several types of novel nanoscale probes that allow reliable, sensitive, accurate and rapid biomedical detection have emerged. We summarize recent developments in three categories of these nanoprobes, including noble metal nanocluster probes, carbon-based nanostructured probes, and unnatural amino acid-based probes. Besides reviewing the utility of different nanoprobes in cell imaging and protein detection, we also discuss the molecular mechanism of nanoprobe detection. Perspectives of novel nanoprobe design based on molecular details of biomedical detection are presented.

关键词： nanomaterials nanoprobes biomedical detection environmental safety

Extreme weather and climate events in China under changing climate

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National Science Review 2020年第5期7卷 938-943页

作者： Weijie zhao An NSR news editor based in Beijing

In the summer of 2003, a heat wave swept Europe and caused more than 70 000 additional fatalities [J.-*** et al., C. R. Biologies 331 (2008)]. Global warming and climate change is no longer a prophecy to be fulfilled, as strong heat waves and typhoons, as well as severe rainfalls, are becoming more severe. Extreme weather and climate events in the world, especially over Europe and North America, are widely studied and frequently

关键词： Extreme weather and climate events in China under changing climate

Analysis of COVID-19 clusters involving vertical transmission in residential buildings in Hong Kong region

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Building Simulation 2023年第5期16卷 701-711页

作者： Pengcheng zhao Department of Mechanical Engineering The University of Hong KongPokfulamHong KongChina

Multiple clusters of coronavirus disease 2019(COVID-19)in Hong Kong have involved vertical transmissions in residential buildings,wherein the flats of confirmed cases were often vertically *** on the buildings and cases associated with 19 such clusters were retrieved and compared with the corresponding data on the entirety of Hong Kong *** transmissions usually occurred in old high-rise buildings with small flat areas and low estate prices during *** addition,infection occurred frequently among the elderly and among upstairs neighbours of index ***-laden aerosols may have been transmitted between flats mostly via shared drainpipes,and the vertical distribution of the confirmed cases in a building varied by its drainage system *** buildings with their entire drainpipes installed indoors,both the upstairs and downstairs neighbours of the index case flats could be *** comparison,buildings with their drainage stacks installed outdoors had lower infection risks and demonstrated a clearer pattern of vertical transmission:most infected cases resided upstairs from the index case flats,indicating that the virus spread could be dominated by the stack *** study provides valuable data and analysis for developing epidemic control strategies for residential buildings.

关键词： drainage system high-rise building infection SARS-CoV-2 stack effect ventilation