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Effect of vortex dynamics and instability characteristics on the induced drag of trailing vortices

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Chinese Journal of Aeronautics 2022年第9期35卷 160-173页

作者： Zepeng cheng Shiyan zhang Yang xiang Chun SHAO Miao zhang Hong liu Yingchun chen School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Aircraft Design and Research Institute Commercial Aircraft Corporation of China Ltd.Shanghai 201210China

In this paper, trailing vortices generated by three wingtip configurations, namely the M6wing and the M6 wing with a blended or split winglet, are experimentally investigated using the Stereo Particle Image Velocimetry(SPIV) technology. Then, linear stability analysis is performed to investigate instability characteristics. Three corresponding trailing vortex patterns, including the isolated trailing vortex without wake(pattern v) and with wake(pattern v-w), co-rotating vortex pair(pattern v-v), are observed in experiments. The strength of trailing vortices, characterized by circulation, is reduced after installing winglets as expected, and the strength of pattern v-v can be further suppressed compared with pattern v-w. Moreover, instability characteristics, such as the eigenvalue spectrum and perturbation mode, are distinctive among these three vortex *** distribution of eigenvalue spectrums indicates that pattern v and pattern v-w are temporally“marginally stable”, while pattern v-v is temporally “unstable.” The primary perturbation mode of pattern v and pattern v-w is the m =-1 helical mode, while |m|>1 for the case of pattern *** effect of vortex dynamics and instability characteristics can be concluded in two ***, the value of induced drag is polluted by about 3% from vortex wandering since vortex wandering affects the tangential velocity and streamwise vorticity of trailing vortices. Secondly, the growth rate and penetration depth perturbation mode affect trailing vortex evolution and further affect induced drag. Specifically, the larger the growth rate and penetration depth are, the more turbulence injects inside the vortex core, thus leading to a quicker and more intense attenuation of trailing vortex, as well as a smaller induced drag. This finding can guide us to manipulate the induced drag in flow control.

关键词： Induced drag Linear stability analysis SPIV Trailing vortex Vortex flow Winglet

Enhanced electrochemical oxidation of benzene and toluene in aqueous environments using Sb–SnO2-doped TiO2 nanotubes modified by hydrophobic polytetrafluoroethylene（PTFE）

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Progress in Natural Science:Materials International 2024年第5期34卷 1009-1020页

作者： Yameng Li Shuo zhang Peizhen Yang Yilin Yang fei chen xiang liu Miao Li School of Environment Tsinghua University Tianjin Key Laboratory of Water Resources and Environment Tianjin Normal University

The presence of benzene and toluene in groundwater poses a serious threat to both aquatic ecosystems and human health. The electrochemical removal of these contaminants is primarily hindered by the low generation yield of reactive oxygen species（ROS）. Herein, polytetrafluoroethylene（PTFE） was electrodeposited onto the surface of Sb–SnO2-doped TiO2nanotubes（TNT/Sb–SnO2/5PTFE-300） to enhance electrochemical activity. The resulting nanoelectrode achieved removal efficiencies of 96.2 % for benzene and 97.6 % for toluene. The minimal variation in the degradation of benzene and toluene following 8 cycles of use verified its stability. Experiments confirmed that ·OH was the primary ROS. Hydrophobic surface of the nanoelectrode promoted the one-electron reaction of H2O oxidation, leading to ·OH concentrations that were 54.0 and 27.5 times higher, respectively, than those produced by Ti/Sb–SnO2, and 4.7 and 2.0 times higher, respectively, than those produced by TNT/Sb–***, intermediate products suggested the ring-opening of benzene and toluene, yielding easily degradable small organic molecules. The electrochemical oxidation（EO） process revealed a competitive relationship between benzene and toluene, with toluene exhibiting stronger competitive effects（kinetic constant was 2.1 times that of benzene）. The efficient nanoelectrode provide a novel approach for the removal of benzene and toluene from aquatic environments through EO.

关键词： Aquatic environment remediation Benzene and toluene removal Competitive oxidation Electrochemical oxidation Hydrophobicity

Cardiomyocyte-specific knockout of ADAM17 ameliorates left ventricular remodeling and function in diabetic cardiomyopathy of mice

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Signal Transduction and Targeted Therapy 2022年第9期7卷 3468-3483页

作者： fei Xue Jing cheng Yanping liu cheng cheng Meng zhang Wenhai Sui Wenqiang chen Panpan Hao Yun zhang cheng zhang The Key Laboratory of Cardiovascular Remodeling and Function Research Chinese Ministry of EducationChinese National Health Commission and Chinese Academy of Medical SciencesThe State and Shandong Province Joint Key Laboratory of Translational Cardiovascular MedicineDepartment of CardiologyQilu HospitalCheeloo College of MedicineShandong UniversityJinan 250012 ShandongChina Heart Center and Beiling Key Laboratory of Hypertension Being Chayang HospitalCapital Medical UniversityBeijing 100020China SCardiovascular Disease Research Center of Shandong First Medical University Central Hospital Afliated to Shandong First Medical UniversityJinanChina

Angiotensin-converting enzyme 2(ACE2)has proven beneficial in attenuating diabetic cardiomyopathy(DCM)but has been found to be a substrate of a disintegrin and metalloprotease protein-17(ADAM17).However,whether ADAM17 plays a role in the pathogenesis and intervention of DCM is *** this study,we created cardiomyocyte-specific knockout of ADAM17(A17^(α-MHCKO))mice,and left ventricular dimension,function,pathology and molecular biology were assessed in ADAM17^(fl/fl) control,A17^(α-MHCKO) control,ADAM17^(fl/fl) diabetic and A17^(α-MHCKO) diabetic *** differentiated H9c2 cells and neonatal rat cardiomyocytes(NRCMs)were used to explore the molecular mechanisms underlying the effect of ADAM17 on *** results showed that protein expression and activity of ADAM17 were upregulated whereas the protein expression of ACE2 was downregulated in the myocardium of diabetic ***-specific knockout of ADAM17 mitigated cardiac fibrosis and cardiomyocyte apoptosis and ameliorated cardiac dysfunction in mice with *** analyses detected a number of genes enriched in metabolic pathways,in particular the AMPK signaling pathway,expressed differentially between the hearts of A17^(α-MHCKO)and ADAM17^(fl/fl)diabetic *** mechanism may involve activated AMPK pathway,increased autophagosome formation and improved autophagic flux,which reduced the apoptotic response in *** addition,hypoxia-inducible factor-1α(HIF-1α)might act as an upstream mediator of upregulated ADAM17 and ADAM17 might affect AMPK signaling viaα1 A-adrenergic receptor(ADRA1A).These results indicated that ADAM17 activity and ACE2 shedding were enhanced in DCM,which was reversed by cardiomyocyte-specific ADAM17 ***,inhibition of ADAM17 may provide a promising approach to the treatment of DCM.

关键词： ACE2 diabetic ADAM17

Rolling reduction-dependent deformation mechanisms and tensile properties in aβtitanium alloy

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Journal of Materials Science & Technology 2022年第9期104卷 183-193页

作者： Zhaoxin Du Qiwei He Ruirun chen fei liu Jingyong zhang fei Yang Xueping Zhao Xiaoming Cui Jun cheng School of Materials Science and Engineering Inner Mongolia University of TechnologyHohhot 010051China National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of TechnologyHarbin 150001China School of Materials Science and Engineering China University of Mining and TechnologyXuzhou 221008China Waikato Centre for Advance Materials and Manufacturing School of EngineeringUniversity of WaikatoHamilton 3240New Zealand State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China

This work investigated the dependence of deformation mechanisms and mechanical properties on cold rolling reductions of the metastable TB8 titanium *** shown that the crystal orientation of the matrix changes with the increasing level of reduction,leading to the activation of complex deformation mechanisms in the *** the rolling reduction is 10%,the deformation mechanisms are dominated by dislocations and{332}deformation *** the reductions increase to 20%-50%,the secondary deformation twinning(SDT)is triggered in primary deformation twins besides the primary kink band is ***,the secondary kink bands and{332}twins have be observed in the primary kink *** the reduction reaches to 60%,the deformation mechanisms are dominated by dislocations and deformation ***,the matrix refined by crisscrossing among the twins,kink bands and other deformation mechanisms during cold rolling,which shortens the dislocation mean free path and then affects the strength and shape of the *** dynamic Hall-Petch effect and the interaction between multi-scale deformed structures control the work hardening behavior of the alloy.

关键词： TB8 titanium alloy Deformation mechanisms Kink band variants Twinning Mechanical properties

Free-radical evolution and decay in cross-linked polytetrafluoroethylene irradiated by gamma-rays

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Nuclear Science and Techniques 2022年第5期33卷 113-125页

作者： fei-xiang Sha Guo-Jun cheng Zi-Yue Xuan Yang liu Wei-Hua liu Xiao-Dong zhang Zhong-Feng Tang School of Materials Science and Engineering Anhui University of Science and TechnologyHuainan 232000China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China National Key Laboratory of Materials Behavior and Evaluation Technology in Space Environment Harbin Institute of TechnologyHarbin 150001China University of Chinese Academy of Sciences Beijing 100049China

Electron spin resonance techniques were employed to investigate the effects of the absorbed dose and post-irradiation conditions on the evolution and decay of free-radicals in cross-linked polytetrafluoroethylene(XPTFE),induced byγ-ray ***-end free-radicals,chain alkyl free-radicals,and tertiary alkyl free-radicals were detected when XPTFE was irradiated under Ar *** corresponding peroxy free-radicals were formed upon exposure of irradiated XPTFE to air;the freeradicals concentration first increased linearly with increasing absorbed dose and then gradually *** free-radicals yield under air atmosphere was greater than that under Ar,and the peroxy free-radicals were preserved for a relatively long time when irradiated XPTFE was stored under air *** chain alkyl free-radicals may be converted to chain end free-radicals byβ-scission,while chain end free-radicals are more sensitive to oxygen than chain alkyl *** the annealing temperature was raised above the a-transition temperature of XPTFE,the decay of the free-radicals was greatly affected and accelerated by the motion of the molecules over the long range.

关键词： Polytetrafluoroethylene Cross-linked polytetrafluoroethylene Electron spinresonance Decay Radiation c-ray

Improvement in structure and superconductivity of YBa2Cu3O6＋δ ceramics superconductors by optimizing sintering processing

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Journal of Rare Earths 2017年第1期35卷 85-89页

作者： JIN fei zhang Hui WANG Wenzhang liu xiang chen Qingming Faculty of Materials Science and Engineering Kunming University of Science and Technology Kunming 650093 China

Polycrystalline YBa2Cu3O6＋δbulks were synthesized by sol-gel method. Sintering processing played a vital role in the evolution of phase structure and microstructure, and thus significantly influenced their superconducting properties. The influence of calcination temperature, sintering temperature, on the bulks structure, morphology and superconducting behaviors were investigated. The results showed that the oxygen content drastically increased with calcination temperature and sintering temperature. The SEM images revealed that the grains grew up monotonously with increase of calcination temperature. With increased calcination and sintering temperature, the resistivity was reduced gradually and the superconducting properties increased. Moreover, it was found that the optimal superconducting properties（with the highest superconducting transition temperature Tc^onset and the narrowest transition width ΔT） were obtained at calcination temperature of 900℃ and sintering temperature of 950 ℃.

关键词： YBa2Cu3O6+δ sol-gel method sintering processing superconducting property rare earths

Duodenal-jejunal bypass reduces serum ceramides via inhibiting intestinal bile acid-farnesoid X receptor pathway

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World Journal of Gastroenterology 2022年第31期28卷 4328-4337页

作者： Zhi-Qiang cheng Tong-Ming liu Peng-fei Ren Chang chen Yan-Lei Wang Yong Dai xiang zhang Department of General Surgery Qilu Hospital of Shandong UniversityJinan 250012Shandong ProvinceChina Department of Colorectal and Anal Surgery Feicheng Hospital Affiliated to Shandong First Medical UniversityFeicheng 271600Shandong ProvinceChina Department of General Surgery Lincheng People’s HospitalDezhou 253500Shandong ProvinceChina

BACKGROUND Bile acids play an important role in the amelioration of type 2 diabetes following duodenal-jejunal bypass(DJB).Serum bile acids are elevated ***,the clinical relevance is not *** acids in the peripheral circulation reflect the amount of bile acids in the ***,a further investigation of luminal bile acids following DJB is of great *** To investigate changes of luminal bile acids following *** Salicylhydroxamic acid(SHAM),DJB,and DJB with oral chenodeoxycholic acid(CDCA)supplementation were performed in a high-fat-diet/streptozotocininduced diabetic rat *** weight,energy intake,oral glucose tolerance test,luminal bile acids,serum ceramides and intestinal ceramide synthesis were analyzed at week 12 *** Compared to SHAM,DJB achieved rapid and durable improvement in glucose tolerance and led to increased total luminal bile acid concentrations with preferentially increased proportion of farnesoid X receptor(FXR)-inhibitory bile acids within the common *** ceramide synthesis was repressed with decreased serum ceramides,and this phenomenon could be partially antagonized by luminal supplementation of FXR activating bile acid *** DJB significantly changes luminal bile acid composition with increased proportion FXR-inhibitory bile acids and reduces serum ceramide *** observations suggest a novel mechanism of bile acids in metabolic regulation after DJB.

关键词： Bariatric surgery Duodenal-jejunal bypass Farnesoid X receptor Ceramide Bile acids Liver fat accumulation

Resveratrol Prevents Vibrio vulnificus-Induced Sepsis by Attenuating Necroptosis

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Biomedical and Environmental Sciences 2023年第2期36卷 135-145页

作者： QIN Ke Wei liu Jian fei WU cheng Lin zhang chen ZHOU Li Jun Central Laboratory The Sixth Medical CentreChinese PLA(People’s Liberation Army)General HospitalBeijing 100048China College of Otolaryngology Head and Neck Surgery The Sixth Medical CentreChinese PLA(People’s Liberation Army)General HospitalBeijing 100048China The Fifth Clinical Medical College of Anhui Medical University Hefei 230032AnhuiChina

Objective This study investigated how the natural phytophenol and potent SIRT1 activator resveratrol(RSV)regulate necroptosis during Vibrio vulnificus(***)-induced sepsis and the potential *** The effect of RSV on *** cytolysin(VVC)-induced necroptosis was analyzed in vitro using CCK-8 and Western blot ***-linked immunosorbent assays and quantitative real-time polymerase chain reaction,western blot,and immunohistochemistry and survival analyses were performed to elucidate the effect and mechanism of RSV on necroptosis in a ***-induced sepsis mouse *** RSV relieved necroptosis induced by VVC in RAW264.7 and MLE12 *** also inhibited the inflammatory response,had a protective effect on histopathological changes,and reduced the expression level of the necroptosis indicator pMLKL in peritoneal macrophages,lung,spleen,and liver tissues of ***-induced septic mice in *** with RSV downregulated the mRNA of the necroptosis indicator and protein expression in peritoneal macrophages and tissues of *** septic *** also improved the survival of ***-induced septic *** Our findings collectively demonstrate that RSV prevented ***-induced sepsis by attenuating necroptosis,highlighting its potency in the clinical management of ***-induced sepsis.

关键词： Vibrio vulnificus Resveratrol Necroptosis Sepsis Inflammation

Preparation, Characterization, and in vitro Release of Biodegradable Erythromycin-gelatin Microspheres

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Chemical Research in Chinese Universities 2008年第2期24卷 196-199页

作者： WANG fei liu Pai JIANG Dan liu cheng-bai zhang Feng-chun chen Xia College of Life Science Jilin University Changchun 130021 P. R. China College of Life Science Beihua University Jilin 132013 P. R. China

Blank and erythromycin-loaded gelatin microspheres were successfully fabricated via emulsion chemical- crosslinking technique. The surface morphology of the microspheres was characterized by scanning electron microscope（SEM） and optical microscope. The results show that the microspheres were spherical and smooth. The particle average size of erythromycin-loaded microspheres was found to be 20.6 μm, with a high purity of more than 90% and with a good dispersibility. The microspheres could be obtained in a high yield. Erythromycin released from the microspheres was monitored in buffer and artificial body fluid at 37 ℃. Average drug content was 27.2%, and erythromycin-loaded gelatin microspheres showed good release profiles with a nearly constant release during 4-8 h in artificial body fluid in vitro degradation studies. These gelatin microspheres are useful for studying and developing various drug-delivery systems.

关键词： In vitro degradation Gelatin Erythromycin Microsphere