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Acoustic characteristics of bi-directional turbines for thermoacoustic generators

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Frontiers in Energy 2022年第6期16卷 1027-1036页

作者： dongdong LIU Yanyan CHEN wei DAI Ercang LUO University of Chinese Academy of Sciences Beijing 101408China Technical Institute of Physics and Chemistry Chinese Academy of SciencesBeijing 100190China

Bi-directional turbines combined with rotary motors may be a feasible option for developing high power thermoacoustic generators with low cost.A general expression for the acoustic characteristics of the bidirectional turbine was proposed based on theoretical derivation,which was validated by computational fluid dynamics modeling of an impulse turbine with fixed guide vanes.The structure of the turbine was optimized primarily using steady flow with an efficiency of near 70%(the shaft power divided by the total energy consumed by the turbine).The turbine in the oscillating flow was treated in a lumped-parameter model to extract the acoustic impedance characteristics from the simulation results.The key acoustic impedance characteristic of the turbine was the resistance and inertance due to complex flow condition in the turbine,whereas the capacitance was treated as an adiabatic case because of the large-scale flow channel relative to the heat penetration depth.Correlations for the impedance were obtained from both theoretical predictions and numerical fittings.The good fit of the correlations shows that these characteristics are valid for describing the bi-directional turbine,providing the basis for optimization of the coupling between the thermoacoustic engine and the turbine using quasi-one-dimensional theory in the frequency domain.

关键词： thermoacoustic power generator acoustic characteristics bi-directional impulse turbine energy conversion

Time Sequence Change-Point Model of Electrostatic State Parameters of Aircraft Engine

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Transactions of Nanjing University of Aeronautics and Astronautics 2018年第1期35卷 126-134页

作者： Fu Yu Wei Dongdong Zuo Hongfu Feng Zhengxing College of Aeronautical Engineering Civil Aviation University of China College of Civil Aviation Nanjing University of Aeronautics and Astronautics

Electrostatic monitoring technology of particle charging information can facilitate online monitoring of aero-engine,which effectively enhances engine fault diagnosis and health managements.Unlike traditional engine state monitoring technologies,aircraft engine monitoring by gas path electrostatic monitoring not only covers the predicted information source itself,but also detects the information that can provide an early warnings for initial fault states through gas path charging levels.This paper establishes a non-stationary time sequence change-point model for anomaly recognition of electrostatic signals based on change-point theory combined with difference method of non-stationary time series.Finally,electrostatic induction data were utilized by the engine life test for a particular aircraft to validate the proposed algorithm.The results indicate that the activity level and the event rate were0.5—0.8(nc)and 50%,respectively,which were far greater than 4—12(pc)and 0—4% under normal working conditions of the engine.

关键词： aero-engine state identification electrostatic monitoring technology time series change-point statistics

Construction of Zn-incorporated Micro/Nano Hierarchical Structure Coatings on Tantalum

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Journal of Bionic Engineering 2020年第6期17卷 1186-1195页

作者： Yongjie wei Yang Hu Mingrui Li dongdong Li Key Laboratory of Automobile Materials of MOE Department of Materials Science and EngineeringJilin UniversityChangchun 130012China

Tantalum(Ta)alloys have been widely used as bone repair materials duc to their excellent biocompatibility.In present work,zinc(Zn)incorporated ceramic coatings with micro/nano hierarchical structure were successfully fabricated on Ta by micro-arc oxidation and hydrothermal treatment.The content of Zn ions is about(1.35士0.3)wt%.Cortex-like rough morphology(Ra:1.504μm)with irregular vermiform slots can be clearly observed on the surface of Ta.More importantly,the coatings resembling the structure of natural bone can release Zn,Ca,and P ions in a controlled and sustained manner.The corrosion resistance ofTa is greatly improved after functionalized with ceramic coatings,confirming by potentiodynamic polarization tests.The bonding strength between the coatings and substrates can be up to 18.9 N.Furthermore,the surface of MAOs-HT@Ta is covered by bonelike apatite after immersed in Simulated Body Fluid(SBF)for three weeks,showing excellently bioactivity.These results suggest that the innovative Zn-incorporated micro/nano hierarchical coatings on Ta may be used as promising candidates for orthopedic implants.

关键词： micro-arc oxidation micro/nano hierarchical structure bioactivity coatings corrosion resistance

Synthesis and Antibacterial Properties of ZIF-8/Ag-Modified Titanium Alloy

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Journal of Bionic Engineering 2022年第2期19卷 507-515页

作者： Mingrui Li Yongjie wei Bowen Ma Yang Hu dongdong Li Xiaoqiang Cui Key Laboratory of Automobile Materials of MOE Department of Materials Science and EngineeringJilin UniversityChangchun 130022China State Key Laboratory for Materials Processing and Die and Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

The loosening of implant due to bacterial infection brings great difficulties to the implantation of bionic titanium devices.In this study,the Zeolitic Imidazolate Framework 8(ZIF-8)and silver ions were added to the surface of titanium alloy to obtain a uniform coating,which has nice biological activity and antibacterial property.The material structure characterizations,such as X-ray diffraction(XRD),scanning electron microscope(SEM),X-ray photoelectron spectroscopy(XPS),proved that titanium is successfully modified with ZIF-8 and silver ions.It has micro-and nano-level characteristics,rough porous morphology,and excellent apatite inducing ability.The water contact angle experiment shows that the addition of ZIF-8 greatly increases the hydrophilicity of material,which provides conditions for the attachment of osteoblasts.The polarization curve obtained from the electrochemical test proves that the addition of ZIF-8 coating improves the corrosion resistance of titanium.The release of silver ion has a strong growth inhibitory effect on E.coli,and exhibits excellent antibacterial properties.Therefore,the preparation of ZIF-8/Ag coatings on 3D printed titanium provides a new option for the development of orthopedic implants.

关键词： Zeolitic imidazolate framework-8 Antibacterial Osseointegration Surface modifcatio

Inducing immunogenic cell death in immuno-oncological therapies

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Chinese Journal of Cancer Research 2022年第1期34卷 1-10页

作者： dongdong Ti Xin Yan Jianshu wei Zhiqiang Wu Yao Wang weidong Han Department of Bio-therapeutic the First Medical CenterChinese PLA General HospitalBeijing 100853China

Immunotherapy has revolutionized cancer treatment and substantially improved patient outcomes with respect to multiple types of tumors.However,most patients cannot benefit from such therapies,mainly due to the intrinsic low immunogenicity of cancer cells(CCs)that allows them to escape recognition by immune cells of the body.Immunogenic cell death(ICD),which is a form of regulated cell death,engages in a complex dialogue between dying CCs and immune cells in the tumor microenvironment(TME),ultimately evoking the damage-associated molecular pattern(DAMP)signals to activate tumor-specific immunity.The ICD inducers mediate the death of CCs and improve both antigenicity and adjuvanticity.At the same time,they reprogram TME with a“cold-warmhot”immune status,ultimately amplifying and sustaining dendritic cell-and T cell-dependent innate sensing as well as the antitumor immune responses.In this review,we discuss how to stimulate ICD based upon the biological properties of CCs that have evolved under diverse stress conditions.Additionally,we highlight how this dynamic interaction contributes to priming tumor immunogenicity,thereby boosting anticancer immune responses.We believe that a deep understanding of these ICD processes will provide a framework for evaluating its vital role in cancer immunotherapy.

关键词： Immunogenic cell death damage-associated molecular pattern tumor immunogenicity antitumor immune responses

Compressive mechanical properties and shape memory effect of NiTi gradient lattice structures fabricated by laser powder bed fusion

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International Journal of Extreme Manufacturing 2022年第4期4卷 189-205页

作者： wei Chen dongdong Gu Jiankai Yang Qin Yang Jie Chen Xianfeng Shen Jiangsu Provincial Engineering Laboratory for Laser Additive Manufacturing of High-Performance Metallic Components College of Materials Science and TechnologyNanjing University of Aeronautics and AstronauticsYudao Street 29Nanjing 210016People's Republic of China Institute of Machinery Manufacturing Technology China Academy of Engineering PhysicsMianyangSichuan 621000People's Republic of China

Laser additive manufacturing (AM) of lattice structures with light weight, excellent impact resistance, and energy absorption performance is receiving considerable attention in aerospace, transportation, and mechanical equipment application fields. In this study, we designed four gradient lattice structures (GLSs) using the topology optimization method, including the unidirectional GLS, the bi-directional increasing GLS, the bi-directional decreasing GLS and the none-GLS. All GLSs were manufactureed by laser powder bed fusion (LPBF). The uniaxial compression tests and finite element analysis were conducted to investigate the influence of gradient distribution features on deformation modes and energy absorption performance of GLSs. The results showed that, compared with the 45° shear fracture characteristic of the none-GLS, the unidirectional GLS, the bi-directional increasing GLS and the bi-directional decreasing GLS had the characteristics of the layer-by-layer fracture, showing considerably improved energy absorption capacity. The bi-directional increasing GLS showed a unique combination of shear fracture and layer-by-layer fracture, having the optimal energy absorption performance with energy absorption and specific energy absorption of 235.6 J and 9.5 J g-1 at 0.5 strain, respectively. Combined with the shape memory effect of NiTi alloy, multiple compression-heat recovery experiments were carried out to verify the shape memory function of LPBF-processed NiTi GLSs. These findings have potential value for the future design of GLSs and the realization of shape memory function of NiTi components through laser AM.

关键词： additive manufacturing laser powder bed fusion gradient lattice structures deformation behavior shape memory effect

Investigation of internal phases of linear SBS modified bitumen at the nanoscale using AFM PF-QNM

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Journal of Traffic and Transportation Engineering(English Edition) 2023年第3期10卷 399-412页

作者： Chengwei Xing Liping Liu wei Jiang Jinhuan Shan Jingjing Xiao dongdong Yuan Wangjie Wu Key Laboratory of Special Area Highway Engineering of Ministry of Education Chang'an UniversityXi'an 710064China School of Highway Chang'an UniversityXi'an 710064China Key Laboratory of Road and Traffic Engineering of Ministry of Education Tongji UniversityShanghai 201804China School of Civil Engineering Chang'an UniversityXi'an 710064China

Currently,few studies explore the internal phases of styrene-butadiene-styrene(SBS)modified bitumen at the nanoscale,though the surface phases of SBS modified bitumen have been deeply understood through a lot of research.The present study uses the atomic force microscopy(AFM)peak force quantitative nanomechanical mode(PF-QNM)to investigate the nanomechanical properties of the interior of linear SBS modified bitumen and corresponding mastics at the nanoscale.Firstly,the suitable experimental methods for the interior of bitumen and mastics are explored.Then,the phase relationship between surfaces and interiors of linear SBS modified bitumen is determined by analyzing nanomechanical properties.On this basis,in comparison with the internal phases of base bitumen,the effect of modifiers on phases is deeply investigated.Finally,the internal phases of linear SBS modified bituminous mastics are further investigated.The results reveal that the interior of linear SBS modified bitumen only has two phases,which form in a manner like periphase and paraphase on the surface.In contrast to base bitumen,linear SBS modified bitumen does not create new phases and change the properties of original phases in the interior,but affects the proportion of A-phase and B-phase and presents the homogenization.Furthermore,due to the influence of preparation methods,only the bitumen area away from the fillers can be imaged by AFM PF-QNM.It can be found that the addition of mineral fillers also slightly changes the internal phase distribution of linear SBS modified bitumen,while the effect is less than that of fillers on base bitumen.

关键词： Road engineering SBS modified bitumen Internal phase AFM PF-QNM

Shape Memory Polymer Composite Booms with Applications in Reel-Type Solar Arrays

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Chinese Journal of Mechanical Engineering 2023年第3期36卷 326-338页

作者： Hong Xiao Sijie Wu dongdong Xie Hongwei Guo Li Ma Yuxuan wei Rongqiang Liu State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150006China Yinhe Hangtian Internet Technology Co. Ltd.Beijing 100192China China Academy of Space Technology Beijing 100098China

Solar arrays are the primary energy source for spacecraft.Although traditional rigid solar arrays improve power supply,the quality increases proportionally.Hence,it is difficult to satisfy the requirements of high-power and low-cost space applications.In this study,a shape-memory polymer composite(SMPC)boom was designed,fabricated,and characterized for flexible reel-type solar arrays.The SMPC boom was fabricated from a smart material,a shape-memory polymer composite,whose mechanical properties were tested.Additionally,a mathematical model of the bending stiffness of the SMPC boom was developed,and the bending and buckling behaviors of the boom were further analyzed using the ABAQUS software.An SMPC boom was fabricated to demonstrate its shape memory characteristics,and the driving force of the booms with varying geometric parameters was investigated.We also designed and manufactured a reel-type solar array based on an SMPC boom and verified its self-deployment capability.The results indicated that the SMPC boom can be used as a deployable unit to roll out flexible solar arrays.

关键词： Shape memory polymer composite Reel-type solar array Deployable boom Bending behavior

Pd nano-catalyst supported on biowaste-derived porous nanofibrous carbon microspheres for efficient catalysis

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化学科学与工程前沿:英文版 2023年第9期17卷 1289-1300页

作者： Xianglin Pei Siyu Long Lingyu Zhang Zhuoyue Liu wei Gong Aiwen Lei dongdong Ye School of Materials and Architectural Engineering Guizhou Normal UniversityGuiyang550025China College of Chemistry and Molecular Sciences Wuhan UniversityWuhan430072China School of Textile Materials and Engineering Wuyi UniversityJiangmen529020China Guizhou Key Laboratory of Inorganic Nonmetallic Functional Materials Guizhou Normal UniversityGuiyang550025China

Environmental pollution caused by the presence of aromatic aldehydes and dyes in wastewater is a serious global concern. An effective strategy for the removal of these pollutants is their catalytic conversion, possibly to valuable compounds. Therefore, the design of efficient, stable and long-lifetime catalysts is a worthwhile research goal. Herein, we used nanofibrous carbon microspheres (NCM) derived from the carbohydrate chitin present in seafood waste, and characterized by interconnected nanofibrous networks and N/O-containing groups, as carriers for the manufacture of a highly dispersed, efficient and stable Pd nano-catalyst (mean diameter ca. 2.52 nm). Importantly, the carbonised chitin’s graphitized structure, defect presence and large surface area could promote the transport of electrons between NCM and Pd, thereby endowing NCM supported Pd catalyst with high catalytic activity. The NCM supported Pd catalyst was employed in the degradation of some representative dyes and the chemoselective hydrogenation of aromatic aldehydes;this species exhibited excellent catalytic activity and stability, as well as applicability to a broad range of aromatic aldehydes, suggesting its potential use in green industrial catalysis.

关键词： biowaste chitin nanofibrous palladium nano-catalyst catalysis