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Experimental and numerical investigation on the gas leakage regime for ventilated tail cavity of an underwater vehicle

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Journal of Hydrodynamics 2023年第1期35卷 46-60页

作者： Xiao-bo Quan Shao-Hua Cheng College of Shipbuilding Engineering Harbin Engineering UniversityHarbin150001China China Academy of Launch Vehicle Technology Beijing100076China Beijing Institute of Astronautical Systems Engineering Beijing100076China

The objective of this paper is mainly to investigate the ventilated tail cavity flow of an underwater vehicle with focus on the gas leakage regime by experimental and numerical methods.A high-speed camera and pressure measurement system are used to record the cavity flow patterns and pressure behavior,respectively.The numerical simulation is carried out with volume of fluid(VOF)model and Filter-based turbulence model(FBM).Good agreement can be obtained between the experimental and numerical results.There are three gas leakage types in the evolution of the intact tail cavity,i.e.,twin-vortex tube entrainment(TVTE),toroidal vortex shedding(TVS)and hybrid twin-vortex tube entrainment and toroidal vortex shedding(TVTE-TVS).With the increase of Fr,the unsteady behavior of the cavity with different gas leakage types becomes more apparent.The internal flow characteristics revealed three distinct regions including the ventilation influence region,the reverse flow region and the high shear flow region and have an important effect on the transition of gas leakage regime.

关键词： Ventilated tail cavity gas leakage regime unsteady behavior internal flow characteristics

Modified strict sperm morphology threshold aids in the clinical selection of conventional in vitro fertilization(IVF)or intracytoplasmic sperm injection(ICSI)

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Asian Journal of Andrology 2022年第1期24卷 62-66页

作者： Yong Zhu Feng Zhang Hua Cheng Xiao-Xi Sun Feng Jiang Obstetrics and Gynecology Hospital Fudan UniversityShanghai 200011China Shanghai Ji Ai Genetics and IVF Institute Obstetrics and Gynecology HospitalFudan UniversityShanghai 200011China

For infertility treatment,the selection of in vitro fertilization(IVF)or intracytoplasmic sperm injection(ICSI)is decided by multiplying indicators(including fallopian tube factors,semen count,and semen motility),except for sperm morphology.In this study,we conducted a retrospective analysis,from implantation to birth,over a period of 5 years.A total of 1873 couples with primary or secondary fallopian tube factors and an increased defective sperm morphology rate(DSMR)were divided into different groups to receive IVF or ICSI cycles.By comparing the outcomes,we found that the F1 group(DSMR98%,IVF group 3;P98%,ICSI group 3)had higher cleavage rate(P<0.001),biochemical pregnancy rate(P<0.05),clinical pregnancy rate(P<0.05)and live birth rate(P<0.05)than the F3 group.However,the ICSI subgroup had a lower two pronuclei fertilization rate than the IVF subgroup(P<0.05).Our data suggest that the sperm morphology should also be considered when selecting IVF or ICSI combined with other semen parameters before the first assisted reproductive technologies(ART)cycle,especially for males with severe sperm defects.

关键词： clinical outcome in vitro fertilization intracytoplasmic sperm injection sperm morphology

Breaking mechanism and control technology of sandstone straight roof in thin bedrock stope

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International Journal of Mining Science and Technology 2020年第2期30卷 259-263页

作者： hualei Zhang Min Tu Hua Cheng Yongzhi Tang Key Laboratory of Safety and High-Efficiency Coal Mining Ministry of Education Anhui University of Science and TechnologyHuainan 232001China School of Resources and Environmental Engineering Anhui UniversityHefei 230039China huainan Mining Group Huainan 232001China

The key problem to be solved urgently is how to avoid the occurrence of support break-off and water inrush in the stoping of sandstone straight roof under the action of load transfer in unconsolidated aquifer.For this reason,taking the thin bedrock 1602(3)working face of huainan(the middle part of Anhui Province)Panyi Coal Mine as the engineering background,this study establishes the stope mining model by using the discrete element UDEC software and the mathematics mechanical model of the support load,and analyzes the reason of support crushing and decides to re-mining the working face by using the compulsive roof caving method.It is concluded that when the working face of sandstone straight roof is broken,the"voussoir beam"structure cannot be formed and acts on the support in the form of cantilever beam,but only when it falls to the high key stratum can the"voussoir beam"structure be formed and at this point,at this time,the bracket bears the weight of the rock layer in the range from the fractured sandstone layer to the lower critical layer.The working resistance of the support increases with the increase of the thickness and the breaking length of straight sandstone roof.When the breaking length of the roof reaches a certain extreme value,the support crushing accidents will occur.Managing roof with compulsive roof caving method can reduce the intensity of rock pressure in the stope,and the working face can be safely stoped,which provides a certain reference for similar conditions.

关键词： Thin bedrock Key stratum Compulsive roof caving

Few-layer metasurfaces with engineered structural symmetry

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Science China(Physics,Mechanics & Astronomy) 2021年第6期64卷 125-126页

作者： Zhancheng Li Hua Cheng ShuQi Chen Key Laboratory of Weak Light Nonlinear Photonics Ministry of EducationSchool of Physics and TEDA Institute of Applied PhysicsNankai UniversityTianjin 300071China The Collaboraive Innovation Center of Extreme Optics Shanxi UnjversityTaiyuan 030006China Collaborative Innovation Center of Light Manipulations and Applications Shandong Normal UniversityJinan 250358China

Metasurfaces are planar arrays composed of artificial nanostructures at the subwavelength scale.Since the first demonstration of their excellent capacity in the phase manipulation of optical waves,metasurfaces have attracted increasing attention in optics and other disciplines,with extraordinary progress over the past decade.The unique capabilities of metasurfaces in the multidimensional manipulation of optical waves have made them versatile and powerful platforms for integrating and minimizing optical devices[1,2].

关键词： surfaces symmetry versatile

A Reliable Iteration Algorithm for One-Bit Compressive Sensing on the Unit Sphere

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 801-822页

作者： Yan-cheng LU Ning BI An-hua WAN School of Mathematics Sun Yat-sen UniversityGuangzhou 510275China

The one-bit compressed sensing problem is of fundamental importance in many areas,such as wireless communication,statistics,and so on.However,the optimization of one-bit problem coustrained on the unit sphere lacks an algorithm with rigorous mathematical proof of convergence and validity.In this paper,an iteration algorithm is established based on difference-of-convex algorithm for the one-bit compressed sensing problem constrained on the unit sphere,with iterating formula■,where C is the convex cone generated by the one-bit measurements andη_(1)>η_(2)>1/2.The new algorithm is proved to converge as long as the initial point is on the unit sphere and accords with the measurements,and the convergence to the global minimum point of the l_(1)norm is discussed.

关键词： one-bit compressed sensing difference of convex algorithm iteration algorithm ■1-minimization

Layered coordination polymer with two-dimensional covalent bismuth-organic networks:Semiconductor and lithium ion storage

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Nano Research 2024年第3期17卷 2181-2185页

作者： Mu-Qing Li Yulin Cao Lei Qin Hua Cheng Weimin Yang Zhouguang Lu School of Materials Science and Environmental Engineering Shenzhen Polytechnic UniversityShenzhen 518055China Industrial Training Center Shenzhen Polytechnic UniversityShenzhen 518055China Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Department of Chemistry Southern University of Science and TechnologyShenzhen 518055China

Single crystals of a bismuth-based coordination polymer(CP)with carboxyl-thiol ligands,[Bi(C_(8)H_(2)O_(4)S_(2))(C2H8N)]n(Bi-DSBDC-DMA,DMBDC=2,5-disulfur-1,4-dicarboxylate,DMA=dimethylamine),have been successfully synthesized.X-ray diffraction analysis reveals that Bi-DSBDC-DMA possesses a layered structure,with two-dimensional(2D)Bi-DSBDC networks alternating with layers composed of dimethylamine ions.This material demonstrates semiconducting properties,featuring an optical bandgap of 2.2 eV and an electrical conductivity of 2×10^(-8) S/cm.Furthermore,electrodes based on this material exhibit a capacity of 250 mAh/g after 200 cycles for lithium-ion storage.

关键词： bismuth layer coordination polymer(CP) semiconductor lithium ion storage

Imidodiphosphorimidates (IDPis): Catalyst Motifs with Unprecedented Reactivity and Selectivity

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Chinese Journal of Chemistry 2023年第6期41卷 685-694页

作者： Jun Kee cheng Shao-hua Xiang Bin Tan Shenzhen Grubbs Institute and Department of Chemistry Guangdong Provincial Key Laboratory of CatalysisSouthern University of Science and TechnologyShenzhenGuangdong 518055China Academy for Advanced Interdisciplinary Studies Southern University of Science and TechnologyShenzhenGuangdong 518055China

The conceptually designed imidodiphosphorimidates(IDPis)have emerged as one of the most potent classes of chiral acid catalysts.They are characterized by enzyme-like,highly confined active site and high acidity,which underlie their wide-reaching applications as Bronsted acid catalysts and as precatalysts for silylium Lewis acids.Many carbon-carbon and carbon-heteroatom bond formation reactions that were deemed intractable could now be attained with spectacular reactivity and selectivity.Substrates that are small,unbiased and/or possess insufficient reactivity such as simple alkenes could now be engaged.The high structural confinement is particularly invaluable to control stereo-and chemoselectivity.The well-defined steric environment offers unique opportunity to control high-energy but structurally unbiased cation intermediates such as the norbonyl cations.Beyond practical appeals such as good scalability as well as ease and modularity of preparation,the extremely low pre-catalyst loadings required to achieve high turnover and stereoselectivity have also come to define a new frontier in organocatalysis.

关键词： Bronsted acid catalyst Lewis acid catalyst Silylium ACDC Imidodiphosphorimidates Asymmetric organocatalysis

Smart Multiple Wetting Control on ZnO Coated Shape Memory Polymer Arrays

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Chemical Research in Chinese Universities 2023年第1期39卷 151-158页

作者： WANG Xiaonan WANG Bohan LAI hua cheng Zhongjun State Key Laboratory of Urban Water Resource&Environment School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin150001P.R.China

Recently,surfaces with intelligent wetting controllability have aroused increased attention.Endowing the surface with stimuli-responsive surface chemistry and tunable surface microstructure can achieve a surface with smart wetting performances.However,almost all existing surfaces only focused on single surface chemistry or micromorphology,thus to achieve smart multiple wetting regulation is still difficult.Herein,we report a ZnO coated shape memory polymer(SMP)surface,and the surface chemistry and micromorphology can be synergistically regulated.ZnO can provide adjustable surface chemistry under UV irradiation,and SMP can offer tunable micromorphology due to its shape memory effect(SME).Based on the combined effect between the above two features,surface wetting performance can be smartly regulated among multiple states.Moreover,due to the excellent controllability of the surface,the application in directional droplet transportation was also demonstrated.This paper offers a new surface with tunability in both surface chemistry and micromorphology,and given the excellent wetting controllability,the surface is believed to be applied in a lot of fields,such as droplet manipulation,fluidic devices and selective catalysis.

关键词： Wetting control Shape memory polymer ZnO Reversible transition

Extended-state-observer-based robust torsional vibration suppression for rolling mill main drive system with input saturation

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Journal of Iron and Steel Research(International) 2023年第5期30卷 985-993页

作者： Jia-qiang Chen Shu-zong Chen Chang-chun hua cheng Jia cheng Qian Institute of Electrical Engineering Yanshan UniversityQinhuangdao 066004HebeiChina National Engineering Research Center for Equipment and Technology of Cold Strip Rolling Yanshan UniversityQinhuangdao 066004HebeiChina

A robust torsional vibration suppression strategy is proposed for the main drive system of the rolling mill subject to uncertainties,disturbances and input saturation.With given model information incorporated into observer design,an extended state observer that relies only on roller speed measurements is developed to estimate the system states and lumped uncertainties of the rolling mill main drive system.To handle the motor torque saturation,an auxiliary signal system with the same order as the plant is constructed.The error between the control input and plant input is taken as the input of the constructed auxiliary system,and a number of signals are generated to compensate for the effect of the motor torque saturation.Furthermore,a robust output feedback controller is introduced to obtain better transient and steady-state performance of the rolling mill main drive system and the stability of the closed-loop system is strictly proved via Lyapunov theory.Finally,comparative simulations are performed to verify the effectiveness and superiority of the proposed control strategy.

关键词： Rolling mill Main drive system Vibration suppression Extended state observer Input saturation