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Effects of synthetic jet frequency on the separated flow in a diffusing S-duct

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航空动力学报 2016年第2期31卷 432-442页

作者： HE Peng dong jin-zhong School of Energy and Power Engineering Beijing University of Aeronautics and Astronautics

Numerical simulations were carried out to investigate the effects of synthetic jet actuation frequency on the separated flow in a diffusing *** Reynolds number based on the entrance height was9.78×*** first,the numerical model was validated with experimental data,and then,the interaction between the separated flow and the synthetic jets at different frequencies was *** results demonstrate that the control effect is significantly dependent on the momentum mixing enhancement between inside of the separated boundary layer and the outer *** exists a narrow range of actuation frequency,in which effective separation control can be achieved using synthetic jets.A dimensionless frequency F+=1.0is identified as the optimal frequency,with a momentum coefficient of 1.62×10-3,the separation area is reduced about46%,and the aerodynamic performance of the S-duct is also greatly improved compared to uncontrolled *** analysis reveals that the choice of actuation frequency is mainly determined by the momentum flux produced by a single ejection and the spacing between adjacent ejections,the optimal frequency case can be understood as a balance between the two *** addition,it is found that the synthetic jets can also suppress the secondary flows while decreasing the separation.

关键词： active flow control boundary layer separation synthetic jet actuation frequency S-duct

Experiment of heat transfer in oscillating turbulent flow in a pipe with constant heat flux

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航空动力学报 2013年第9期28卷 1949-1955页

作者： LI Ming-zhen dong jin-zhong School of Energy and Power Engineering Beijing University of Aeronautics and Astronautics

Heat transfer characteristics of oscillating turbulent air flow in a pipe heated with constant heat flux were experimentally *** experiments were performed over a range of 245.7 to 902 of the kinetic Reynolds number and 25 to 175 of the dimensionless oscillation *** effects of these two dimensionless parameters were *** results show that the cycle-averaged local Nusselt number increases with both the kinetic Reynolds number and the dimensionless oscillation *** space-cycle averaged Nusselt number also effectively increases with the kinetic Reynolds number and the dimensionless oscillation *** on the experimental data,a correlation equation of the space-cycle averaged Nusselt number for air in terms of these two dimensionless parameters has been obtained.

关键词： oscillating turbulent flow heat transfer kinetic Reynolds number Nusselt number constant heat flux

C_(Ar)-Br bond cleavage via cooperative EnT/NHC catalysis: mild access to indolines

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Science China Chemistry 2024年第3期67卷 922-927页

作者： Yi-Xiong dong Cao-Bo Li Ming-Lei jin zhong-Hua Gao Song Ye Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Molecular Recognition and FunctionCAS Research/Education Center for Excellence in Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

The cooperative visible-light mediated and NHC-catalyzed dearomative arylation-acylation of N-(2-bromobenzoyl)indoles with aldehydes was developed, affording the corresponding highly functionalized polycyclic indolines in moderate to good yields with exclusive diastereoselectivities. Mechanism investigations support the activation of CAr-Br bond via visible-light mediated energy transfer(EnT) and the following single-electron-transfer(SET) with Breslow intermediate under NHC catalysis to give key aryl radical and ketyl radical. This protocol demonstrates the cleavage of CAr-Br bond under mild cooperative EnT/NHC catalysis.

关键词： energy transfer N-heterocyclic carbenes photocatalysis aryl radicals indolines

A novel DPSS filter optimization scheme to reduce the intrinsic interference of FBMC-QAM systems

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High Technology Letters 2024年第1期30卷 68-74页

作者：董琪阳 MA Tianming jin Jie WU zhong School of Electrical and Electronic Engineering Shanghai University of Engineering ScienceShanghai 201620P.R.China

In order to reduce the intrinsic interference of the filter bank multicarrier-quadrature amplitude modulation(FBMC-QAM)system,a novel filter optimization scheme based on discrete prolate spheroidal sequences(DPSS)is ***,a prototype filter function based on DPSS is designed,since the eigenvalue can be used as an indicator of the energy concentration of DPSS,so a threshold is set,and the sequence with the most concentrated energy is selected under the threshold,that is,the sequence with the eigenvalue higher than the threshold,and the prototype filter function is rewritten as a weighted sum function of multiple *** the energy constraints of the filter,the relationship between the eigenvectors and the intrinsic interference function is established,and the function problem is transformed into an optimization problem for the weighted *** the interior point method,the most suitable weight is found to obtain the minimum intrinsic interference *** analysis and simulation results show that compared with the prototype filters such as Type1 and CaseC,the DPSS filter applying the proposed optimization algorithm can effectively suppress the intrinsic interference of the system and obtain a better bit error rate(BER)performance.

关键词： filter bank multicarrier-quadrature amplitude modulation(FBMC-QAM) intrinsic interference discrete prolate spheroidal sequences(DPSS) interior point method

Nano polystyrene microplastics could accumulate in Nile tilapia(Oreochromis niloticus):Negatively impacts on the intestinal and liver health through water exposure

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Journal of Environmental Sciences 2024年第3期137卷 604-614页

作者： Di Wu Xing Lu Li-Xue dong Juan Tian jin Deng Lei Wei Hua Wen Shan zhong Ming Jiang School of Basic Medical Sciences Wuhan UniversityWuhan 430071China Key Laboratory of Freshwater Biodiversity Conservation Ministry of Agriculture and Rural AffairsYangtze River Fisheries Research InstituteChinese Academy of Fishery SciencesWuhan 430223China Hubei Province Key Laboratory of Allergy and Immunology Wuhan 430071China

Microplastics(MPs)have become a significant concern for their potential ***,the correlation between the size of plastic particles and their toxicity remains ***,we investigate the toxic effects of different sizes(80 nm,800 nm,8μm and 80μm)polystyrene MPs(PS-MPs)on the model organism Nile tilapia(Oreochromis niloticus).The results of bioluminescent imaging indicate that the 80 nm PS-MPs are more likely to invade the body.H&E staining shows severe damage on the intestinal villi and distinct hepatic steatosis in the 80 nm *** U labeling shows that the proliferation activity of intestinal and liver cells reduces significantly in the 80 nm *** gut microbiome analysis shows a severe imbalance of gut microbiota homeostasis in the 80 nm *** analysis of liver transcriptomics and metabolomics shows that the liver lipid metabolism is disordered in the 80 nm *** conclusion,this study confirms that the 80 nm PS-MPs are more likely to induce intestinal and liver *** the above lay the foundation for further study on the pathological damage of MPs to other organisms.

关键词： Microplastics(MPs) Intestinal toxicity Liver toxicity Gut microbiome Lipid metabolism

New Results in Cooperative Adaptive Optimal Output Regulation

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Journal of Systems Science & Complexity 2024年第1期37卷 253-272页

作者： dong Yuchen GAO Weinan JIANG zhong-Ping State Key Laboratory of Synthetical Automation for Process Industries Northeastern UniversityShenyang 110819China Department of Electrical and Computer Engineering Tandon School of EngineeringNew York UniversityBrooklynNY 11201USA

This paper investigates the cooperative adaptive optimal output regulation problem of continuous-time linear multi-agent *** the multi-agent system dynamics are uncertain,solving regulator equations and the corresponding algebraic Riccati equations is challenging,especially for high-order *** this paper,a novel method is proposed to approximate the solution of regulator equations,i.e.,gradient descent *** is worth noting that this method obtains gradients through online data rather than model information.A data-driven distributed adaptive suboptimal controller is developed by adaptive dynamic programming,so that each follower can achieve asymptotic tracking and disturbance ***,the effectiveness of the proposed control method is validated by simulations.

关键词： Adaptive dynamic programming cooperative output regulation gradient descent method multi-agent systems.

Reliable calculations of nuclear binding energies by the Gaussian process of machine learning

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Nuclear Science and Techniques 2024年第6期35卷 130-144页

作者： Zi-Yi Yuan dong Bai Zhen Wang zhong-Zhou Ren School of Physics Science and Engineering Tongji UniversityShanghai 200092China College of Science Hohai UniversityNanjing 211100China Key Laboratory of Advanced Micro-Structure Materials Ministry of EducationShanghai 200092China

Reliable calculations of nuclear binding energies are crucial for advancing the research of nuclear physics. Machine learning provides an innovative approach to exploring complex physical problems. In this study, the nuclear binding energies are modeled directly using a machine-learning method called the Gaussian process. First, the binding energies for 2238 nuclei with Z > 20 and N > 20 are calculated using the Gaussian process in a physically motivated feature space, yielding an average deviation of 0.046 MeV and a standard deviation of 0.066 MeV. The results show the good learning ability of the Gaussian process in the studies of binding energies. Then, the predictive power of the Gaussian process is studied by calculating the binding energies for 108 nuclei newly included in AME2020. The theoretical results are in good agreement with the experimental data, reflecting the good predictive power of the Gaussian process. Moreover, the α-decay energies for 1169 nuclei with 50 ≤ Z ≤ 110 are derived from the theoretical binding energies calculated using the Gaussian process. The average deviation and the standard deviation are, respectively, 0.047 MeV and 0.070 MeV. Noticeably, the calculated α-decay energies for the two new isotopes ^ (204 )Ac(Huang et al. Phys Lett B 834, 137484(2022)) and ^ (207) Th(Yang et al. Phys Rev C 105, L051302(2022)) agree well with the latest experimental data. These results demonstrate that the Gaussian process is reliable for the calculations of nuclear binding energies. Finally, the α-decay properties of some unknown actinide nuclei are predicted using the Gaussian process. The predicted results can be useful guides for future research on binding energies and α-decay properties.

关键词： Nuclear binding energies decay Machine learning Gaussian process

An improved laser flash method for thermal conductivity measurement of molten salts

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Progress in Natural Science:Materials International 2024年第2期34卷 345-353页

作者： Shiyan dong Mingzhen Zhang Kaiyuan jin Ronggui Yang State Key Laboratory of Coal Combustion School of Energy and Power Engineering Huazhong University of Science and Technology

Thermal conductivity measurement of high-temperature heat transfer fluids provides a crucial basis for designing utility-scale thermal systems. Molten salts are promising heat transfer and thermal storage fluids in hightemperature thermal energy storage systems, while the molten salt thermal conductivity obtained in existing studies exhibits large deviations due to the high experimental complexity and unstandardized test procedures. In this work, we improve the conventional laser flash analysis method by proposing a theoretical heat transfer model for multi-layer heat conduction and providing a near-optimal molten salt container design. With water as a test sample, the relative error of thermal conductivity measurement using the improved method is 6.3%. The thermal conductivity of Solar Salt from 250 to 400°C, and of Hitec Salt from 160 to 250°C are measured and compared with the previous work. Both results show that the thermal conductivity increases with the temperature *** work will promote the technology standardization for accurately acquiring the thermal conductivity of molten salts or other similar high-temperature heat transfer fluids.

关键词： Laser flash analysis Molten salt Multi-layer heat conduction Thermal conductivity Thermal energy storage

Super-high bed sintering for iron ores:behaviors,causes and solutions of horizontal segregation on strand

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Journal of Iron and Steel Research(International) 2024年第7期31卷 1590-1596页

作者： Liang-ping Xu Hui-bo Liu zhong-lin dong Qiang zhong Yu-chao Zhao Guang-hui Li School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083HunanChina

Horizontal segregation has been a constraint to the development and application of super-high bed *** eliminate the horizontal segregation of super-high bed sintering,several typical sintering machines were sampled and analyzed,and theoretical calculation was made to compare the bed depth and their differences in different areas within the mixture ***,solutions were proposed and applied to a 265 m^(2) sintering *** results showed that the horizontal seg-regation of the 265 m^(2) sintering machine was dominated by particles larger than 8 mm with horizontal segregation degree of 0.48,while 360 and 550 m^(2) sintering machines were affected by 5-8 mm and 1-3 mm particles with horizontal segregation degree of 0.27 and 0.31,*** analysis indicated the different segregation distribution results from the matching of the bed depth of each area within the mixture ***,the horizontal segregation degree not larger than 0.06 was achieved by optimizing the time parameters and the division of three zones on the 265 m^(2) sintering machine.

关键词： Super-high bed sintering Horizontal segregation Feeder Particle distribution Agglomeration