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Theories and methods for designing hypersonic high-enthalpy flow nozzles

Chinese Journal of Aeronautics 2022年第1期35卷 318-339页

作者： Yunpeng WANG Zonglin jiang State Key Laboratory of High Temperature Gas Dynamics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

Hypersonic high-enthalpy wind tunnels have been a challenge to ground tests in aerospace research area for decades and its test flow uniformity is one of the most important parameters for evaluating wind tunnel *** to the performance requirement,theories and methods for designing hypersonic flow nozzles at high enthalpy conditions are quite difficult,but very interesting topics,especially when air molecule dissociations take place in wind tunnel test gas *** this paper,fundamental theories and important methods for nozzle designs are briefly reviewed with the emphasis on two-dimensional axisymmetric nozzles for hypersonic high-enthalpy wind tunnels,including the Method of Characteristics(MOC),the graphic design method,the Sivells method,the theory for boundary correction,and the CFD-based design optimization *** theories and methods had been proposed based on several physical issues,respectively,which play important roles in nozzle flow expansion *** issues cover the expansion wave generation and reflection,the boundary layer development,the real gas effect of hypersonic high-enthalpy *** arising from applications of these methods in hypersonic high-enthalpy nozzle design are discussed in detail and the state of the art of the nozzle design technologies that have reached for decades is summarized with some brief ***,the prospect for the hypersonic nozzle design methods,and its numerical and experimental verifications are provided with from authors’viewpoint for readers’reference.

关键词： Boundary layer correction High-enthalpy flow Hypersonic wind tunnel Nozzle design Real-gas effects

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Heat Transfer and Friction Characteristics of Printed Circuit Heat Exchangers with Different Channel Structures for S-CO_(2) Power System

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Journal of Thermal Science 2024年第3期33卷 1132-1147页

作者： jiang Tao LI Mingjia Key Laboratory of Thermo-Fluid Science and Engineering of Ministry of Education School of Energy and Power EngineeringXi’an Jiaotong UniversityXi’an710049China School of Mechanical Engineering Beijing Institute of TechnologyBeijing100081China

Printed circuit heat exchanger(PCHE)has been widely used in supercritical carbon dioxide(S-CO_(2))power systems because of its high heat transfer efficiency and good ***,due to the large variety of PCHE configurations,channel selection in practical applications lacks a ***,this paper discussed the heat transfer and friction characteristics and the synergy of three fields in the channel under the guidance of the field synergy principle for four typical PCHE ***,the comprehensive performance of four channels was ***,the heat transfer and friction factor correlations for S-CO_(2)in four channels were *** findings demonstrate that the synergy of velocity and pressure fields of the straight channel PCHE is better(β≈180°),so its resistance loss is relatively *** zigzag and sinusoidal wavy channels and the airfoil fins can reduce the angle a between the temperature gradient and velocity,thus enhancing the heat *** sinusoidal wavy channel can reduce flow resistance compared to the zigzag channel due to the rounded *** streamlined airfoil structure can guide the flow and reduce backflow,thus reducing resistance *** the range of Re studied in this paper,the maximum error of the proposed heat transfer and friction factor correlations of PCHE is 7.0%,which shows good fitting *** research in this paper can provide a reference for the selection and design of PCHE with different channel configurations.

关键词： printed circuit heat exchanger supercritical carbon dioxide typical channel structure field synergy analysis

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Towards trustworthy blockchain systems in the era of “Internet of value”: development, challenges, and future trends

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Science China(Information Sciences) 2022年第5期65卷 250-260页

作者： Hai JIN jiang XIAO National Engineering Research Center for Big Data Technology and System Services Computing Technology and System Lab Cluster and Grid Computing Lab School of Computer Science and TechnologyHuazhong University of Science and Technology

Since the advent of cryptocurrencies such as Bitcoin, blockchain, as their underlying technologies,has drawn a massive amount of attention from both academia and the industry. This ever-evolving technology inherits the “genes” of distributed systems, offering significant advantages of immutability, transparency,auditability, and tamper-resistance. These benefits help blockchain re-establish public confidence, and hold the significant promise of reliable information sharing and value transfer. Therefore, blockchain has become the foundation of crucial strategic deployments in countries across the world, and the fundamental basis for building the next generation Web 3.0 — “Internet of value”. In this article, we will start with unraveling the essential ingredients of blockchain technology, and showing the characteristics of each of these ingredients in the context of distributed systems. We will then present the core technical challenges that need to be addressed prior to unleashing its full potential, including its performance, scalability, and cross-chain interoperability. Finally, we will introduce the recent developments of blockchain systems, and discuss the future trends of the blockchain ecosystem.

关键词： blockchain distributed systems internet of value challenges development

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Granulation of m A-modified mRNAs protects their functionality through cellular stress

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Journal of Molecular Cell Biology 2020年第11期12卷 821-822页

作者： Hao jiang Department of Biochemistry and Molecular Genetics University of Virginia School of MedicineCharlottesvilleVA 22908USA

To cope with various stress conditions,cells turn off house-keeping processes and turn on stress-protective pathways(Rabouille and Alberti,2017).A successful strategy would also require cells to efficiently reactivate the essential cellular processes once the stress is *** addition to activation of signaling events,recent studies have shown that formation of certain membraneless assemblies plays a role in stress adaptation(Rabouille and Alberti,2017).

关键词： stress protective activation

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Influence of shock attenuation on tailored operation in free piston shock tunnels

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Chinese Journal of Aeronautics 2021年第2期34卷 279-287页

作者： Hao ZHU Hainan jiang China Academy of Aerospace Aerodynamics Beijing 100074China

The free piston shock tunnel is a type of shock tunnel with high performance. For this type of tunnel, the influence mechanism of shock wave attenuation on tailored operation is explored by numerical simulation and theoretical analysis. By introducing the normalized velocity, the simple constraint equation for shock wave under the tailored operation is deduced. Moreover, the real gas effect is also taken into account in this equation. Based on the equation, the tailored operation of shock tunnels can be predicted with very few calculations. The present study shows that the change rate of the thermodynamic state of the gas behind the shock wave is inconsistent with the attenuation rate of the shock wave, which is the fundamental reason why the wind tunnel achieves tailored operation at a lower Mach number of shock waves. This lower Mach number of shock waves differs from the corresponding ideal value by a factor, which is about the square root of shock attenuation rate.

关键词： Attenuation Constraint equation Free piston shock tunnel Real gas effect Shock wave Tailored operation

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Hybrid Static-dynamic Sensation Electrotactile Feedback for Hand Prosthesis Tactile and Proprioception Feedback

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Journal of Bionic Engineering 2023年第1期20卷 267-277页

作者： Bin Yang Li jiang State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin150001China

Tactile and proprioception feedback are essential to myoelectric hand prostheses control for regaining functionality of lost hands of *** studies focus on tactile feedback,while the lack of appropriate multisensory feedback,especially proprioception feedback,limits the grasping ***,a typical non-invasive stimulation scheme for sensation feedback uses stimulation on the stationary site of the skin continuously,which can lead to fatigue and adaptation of sensation,further reduces the feedback consistency,and increases the cognitive burden for the *** the sensitivity and modality matching of sensation,this study presented a multimodal sensations feedback scheme based on hybrid static-dynamic sensation elicited by multisite Transcutaneous Electrical Nerve Stimulation(TENS)to deliver grasping force and joint position *** the proposed scheme,stimulation of single electrode produced only in-loco tactile sensation under the electrode,and the sensation intensity was adjusted according to grasping force;sequential activation of multi-electrodes produced an illusion dynamic sensation of a stimulus moving,and the velocity and direction of movement were adjusted according to finger joint *** test results demonstrated the identifiability of stimulus in the proposed ***,prosthetic hand closed-loop grasping tasks evaluate the effectiveness of the proposed feedback *** results showed that the proposed feedback scheme could substantially improve the grasping accuracy and *** addition,the study outcomes also demonstrated the benefit of artificial proprioception feedback in grasping rapidity and security.

关键词： TENS-Prosthetic hand control-Bioinspired sensation-Multimodal sensations Proprioception feedback Tactilefeedback Myoelectric control

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Transient Response in a Bi-material Cylinder of Soft Ferromagnetic Material Subjected to Magnetic Shock

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Acta Mechanica Solida Sinica 2021年第2期34卷 286-296页

作者： Zhangjianing Cheng Quan jiang College of Civil Engineering Tongji UniversityShanghai 200092China School of Transportation and Civil EngiTieering Nantong UniveirsityNantong 226019China

The transient response in a bi-material cylinder of soft ferromagnetic material under magnetic shock is investigated in this *** analytical solutions for displacement and stress have been derived using the finite Hankel transform and the Laplace *** numerical examples show that the displacement and stress fields respond dynamically in the bi-material cylinder under magnetic *** derived displacement at the center and radial stress on the surface of the cylinder satisfy the boundary conditions,showing the correctness of *** displacement and stress waves propagate from the surface to the center of the cylinder when the magnetic field is *** stress fields increase from the center to the surface of the cylinder and are much larger than the quasi-static state since the waves reflect,collide and concentrate in the body of the *** method of this paper can be used in the design of soft ferromagnetic structures.

关键词： Soft ferromagnetic material Bi-material cylinder Transient stress Magnetic shock

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Liquid metal-based paper electronics:Materials,methods,and applications

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Science China(Technological Sciences) 2023年第6期66卷 1595-1616页

作者： jiang ChengJie GUO Rui Department of Biomedical Engineering Tianjin UniversityTianjin 300072China

The liquid metals exhibit both the properties of liquids and metals and have a low melting point near room *** a lowcost and easy-to-obtain flexible substrate,paper has significant advantages for large-area and multilayer flexible circuit *** has led to a growing interest in liquid metal-based paper electronics among both scientists and *** order to promote the development and application of liquid metal-based paper electronics,this review will summarize and analyze the progress from three perspectives,including liquid metal inks,printing methods,and their applications.A variety of liquid metalbased electronic inks are introduced,and their advantages and disadvantages are ***,a comparison of typical fabrication methods has been presented,including chemical interaction-based selective adhesion and surface roughness-based transfer printing.A number of emerging applications used and expected to be applied to liquid metal-based paper electronics have been ***,paper electronics based on liquid metals are discussed along with their challenges and opportunities for the further *** the future,further investigations and applications of paper electronics based on liquid metals are expected.

关键词： EGain flexible electronics paper electronics health monitoring

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An improved initial rotor position estimation method using high-frequency pulsating voltage injection for PMSM

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Defence Technology（防务技术） 2024年第3期33卷 19-29页

作者： Yang jiang Ming Cheng School of Electrical Engineering Southeast UniversityNanjing 210096China

High frequency pulsating voltage injection method is a good candidate for detecting the initial rotor position of permanent magnet synchronous ***,traditional methods require a large number of filters,which leads to the deterioration of system stability and dynamic *** order to solve these problems,a new signal demodulation method is proposed in this *** proposed new method can directly obtain the amplitude of high-frequency current,thus eliminating the use of filters,improving system stability and dynamic performance and saving the work of adjusting filter *** addition,a new magnetic polarity detection method is proposed,which is robust to current measurement ***,experiments verify the effectiveness of the method.

关键词： Initial position detection Signal demodulation algorithm Magnetic polarity detection Filter elimination

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Effect of sliding speed on elevated-temperature wear behavior of AISI H13 steel

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Journal of Iron and Steel Research International 2021年第9期28卷 1180-1189页

作者： Yin Zhou Wei jiang School of Shipping and Mechatronic Engineering Taizhou UniversityTaizhou225300JiangsuChina Light Alloy Research Institute Central South UniversityChangsha410083HunanChina

Elevated-temperature wear tests were performed on AISI H13 steel under 50 and 100 r/min at 400–600℃.Through examining the morphology,structure and composition of worn surfaces as well as the microhardness at subsurfaces,the wear mechanisms in various sliding conditions were explored.H13 steel exhibited totally different elevated-temperature wear behavior at two sliding speeds while the high sliding speed would seriously deteriorate its wear *** sliding at two sliding speeds,the wear rate of H13 steel decreased first and then rose with the increase in temperature and the wear rate reached the lowest value(lower than 1×10^(–6)mm^(3)/mm)at 500℃and 50 r/*** wear rate at 600℃was lower than that at 400℃for 50 r/min,but the wear rate at 600℃was higher than that at 400℃for 100 r/min(except for 50 N).At 50 r/min,the wear rate decreased first and then increased with the increase in ***,at 100 r/min,the wear rate monotonically increased with increasing load and reached 33×10^(–6)mm^(3)/mm at 600℃and 150 N,where severe wear *** the other sliding conditions,severe wear did not appear with wear rate lower than 5×10^(–6)mm^(3)/*** mild wear merely prevailed at 500℃and 50 r/min and oxidative wear appeared in the other sliding conditions except for 600℃and 150 N,where severe plastic extrusion wear *** effect of sliding speed on wear behavior was attributed to the changes of tribo-oxide *** elevated-temperature sliding,tribo-oxide particles were more readily retained to form protective tribo-oxide layers on worn surfaces at the lower sliding speed than at the higher sliding speed,so as to protect from wear.

关键词： AISI H13 steel Dry sliding wear Elevated-temperature wear Wear testing Surface analysis Wear mechanism Sliding speed

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