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A compact bimorph rotary piezoelectric actuator with customized small power supply

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Science China(Technological Sciences) 2024年第4期67卷 1185-1195页

作者： DENG Jie liu DaQing WANG WeiYi liu YingXiang School of mechatronics and Engineering Harbin Institute of TechnologyHarbin 150001China

Inertial piezoelectric actuators are widely applied in precision devices with simple structure and accurate ***,existing inertial piezoelectric actuators still face the challenges of rollback motion and bulky power *** this work,an alternate excitation strategy and a customized small power supply for a bimorph rotary piezoelectric actuator(BRPA)are proposed to solve the *** BRPA prototype is designed with a bipedal symmetrical structure,measuring 35 mm in height and 32 mm in diameter,which has a maximum rotation velocity of 0.247 rad/s and a resolution of 0.66μ*** to the bipedal symmetrical structure,the friction directions between the driving feet and the rotor can be coordinated to suppress the *** rollback ratio is almost zero when the phase difference of the exciting signal is set as 180°.The customized power supply is designed and manufactured,whose size is 58 mm×56 mm×46 *** can output signals for the single step mode and the continuous mode,and they are adopted to excite BRPA to achieve a small stroke with one single step and a large stroke with continuous step,***,an experimental system for optical fiber alignment is developed based on the BRPA and the customized small power supply,the experiment has verified the practicability of this work in the precision fields,especially in the miniaturized precision systems.

关键词： inertial piezoelectric actuator customized small power supply single step mode continuous mode rollback suppression miniaturized precision system

Enhanced structural damage behavior of liquid-filled tank by reactive material projectile impact

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Defence Technology（防务技术） 2024年第1期31卷 211-229页

作者： Jianwen Xie Yuanfeng Zheng Zhenyang liu Chengzhe liu Aoxin liu Pengwan Chen Haifu Wang State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China

A series of ballistic experiments were performed to investigate the damage behavior of high velocity reactive material projectiles(RmPs) impacting liquid-filled tanks,and the corresponding hydrodynamic ram(HRAm) was studied in ***/Al/W RmPs with steel-like and aluminum-like densities were prepared by a pressing/sintering *** projectiles impacted a liquid-filled steel tank with front aluminum panel at approximately 1250 m/*** corresponding cavity evolution characteristics and HRAm pressure were recorded by high-speed camera and pressure acquisition system,and further compared to those of steel and aluminum *** different from the conical cavity formed by the inert metal projectile,the cavity formed by the RmP appeared as an ellipsoid with a conical *** RmPs were demonstrated to enhance the radial growth velocity of cavity,the global HRAm pressure amplitude and the front panel damage,indicating the enhanced HRAm and structural damage ***,combining the impact-induced fragmentation and deflagration characteristics,the cavity evolution of RmPs under the combined effect of kinetic energy impact and chemical energy release was *** mechanism of enhanced HRAm pressure induced by the RmPs was further revealed based on the theoretical model of the initial impact wave and the impulse ***,the linear correlation between the deformation-thickness ratio and the non-dimensional impulse for the front panel was obtained and *** was determined that the enhanced near-field impulse induced by the RmPs was the dominant reason for the enhanced structural damage behavior.

关键词： Reactive material projectile Hydrodynamic ram Enhanced structural damage Liquid-filled tank Impact

Automatic modulation recognition of radio fuzes using a DR2D-based adaptive denoising method and textural feature extraction

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Defence Technology（防务技术） 2024年第4期34卷 328-338页

作者： Yangtian liu Xiaopeng Yan Qiang liu Tai An Jian Dai Science and Technology on Electromechanical Dynamic Control Laboratory School of Mechatronical EngineeringBeijing Institute of TechnologyBeijing 100081China China Research and Development Academy of machinery Equipment Beijing 100089China

The identification of intercepted radio fuze modulation types is a prerequisite for decision-making in interference ***,the electromagnetic environment of modern battlefields is complex,and the signal-to-noise ratio(SNR)of such environments is usually low,which makes it difficult to implement accurate recognition of radio *** solve the above problem,a radio fuze automatic modulation recognition(AmR)method for low-SNR environments is ***,an adaptive denoising algorithm based on data rearrangement and the two-dimensional(2D)fast Fourier transform(FFT)(DR2D)is used to reduce the noise of the intercepted radio fuze intermediate frequency(IF)***,the textural features of the denoised IF signal rearranged data matrix are extracted from the statistical indicator vectors of gray-level cooccurrence matrices(GLCms),and support vector machines(SVms)are used for *** DR2D-based adaptive denoising algorithm achieves an average correlation coefficient of more than 0.76 for ten fuze types under SNRs of-10 d B and above,which is higher than that of other typical *** trained SVm classification model achieves an average recognition accuracy of more than 96%on seven modulation types and recognition accuracies of more than 94%on each modulation type under SNRs of-12 d B and above,which represents a good AmR performance of radio fuzes under low SNRs.

关键词： Automatic modulation recognition Adaptive denoising Data rearrangement and the 2D FFT(DR2D) Radio fuze

Effect of heat treatment on microstructure and mechanical properties of selective laser-melted PH13-8mo stainless steel

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Journal of Iron and Steel Research International 2024年第4期31卷 945-955页

作者： Yuan Zhang Xiang liu Chang-jun Wang Chang liu School of material Science and Engineering Kunming University of Science and TechnologyKunming 650093YunnanChina Central Iron&Steel Research Institute Co. Ltd.Beijing 100081China

PH13-8mo stainless steel powder with high sphericity and well fluidity was prepared by the plasma rotating electrode *** formed parts with ultra-high purity were manufactured by selective laser *** tensile and impact mechanical properties of the printed parts under three heat treatment regimes were compared to those without heat *** microstructure,grain orientation and phase composition were characterized by electron-backscatter diffraction,X-ray diffraction and transmission electron *** characterization results reveal that the addition of heat treatment makes the grains enlarge,and after different heat treatments,the average grain size from 1.51μm in the printed state increases to 2.78,3.09 and 2.06μm,*** formed parts are mainly composed of martensite and retained ***,the NiAl and m23C precipitates form,which are the major strengthening phases of PH13-8mo stainless *** optimal heat treatment process is 925℃×1 h water cooling(WC)+0℃×2 h air cooling(AC)+540℃×4 h *** this heat treatment process,PH13-8mo formed parts have the optimal comprehensive mechanical properties:the tensile strength,yield strength and impact energy KU2 are 1492 mPa,1432 mPa and 63 J,*** strengthening and toughening via heat treatment are mainly attributed to dislocation strengthening,the formation of NiAl and m23Co precipitates and the change of volume fraction of the retained austenite.

关键词： High-strength stainless steel-Selective laser melting-Heat treatment microstructure mechanical property

Polyimide covalent organic frameworks as efficient solid-state Li^(+) electrolytes

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Science China Chemistry 2024年第5期67卷 1647-1652页

作者： Xu liu Shi Wang Siqi liu Chengfang liu Xiangchun Li Jian Wu Dazhi Li Shihao Xu Chongyang liu Wen-Yong Lai State Key Laboratory of Organic Electronics and Information Displays(SKLOEID) Institute of Advanced Materials(IAM)School of Chemistry and Life SciencesNanjing University of Posts&TelecommunicationsNanjing 210023China

Covalent organic frameworks(COFs) are attractive porous crystalline materials with extremely high stability, easy functionalization, and open channels, which are expected to be unique ion conductors/transporters in lithium ion batteries(LIBs). Despite recent advances, low ion conductivity and low transference number, resulting in low charging/discharging rate, low energy density, and short battery life, are the main issues that limit their direct application as solid electrolytes in LIBs. Here, we designed and synthesized a novel polyimide COF, namely, TAPA-PDI-COF, with abundant C=O groups, which has been successfully employed as high-performance solid electrolytes by doping TAPA-PDI-COF and succinonitrile(SN). Both the well-defined nanochannels of COFs and SN confined in the well-aligned channels restricted the free migration of anions, while C=O on COFs and CN groups of SN enhanced Li^(+) transport, thus achieving a high ion conductivity of 0.102 m S cm^(-1)at 80 °C and a high lithium-ion transference number of 0.855 at room temperature. According to density functional theory(DFT)calculations, Li-ion migration mainly adopted in-plane transport rather than the axial pathway, which may be due to the shorter hopping distances in the planar pathway. The results suggest an effective strategy for the design and development of all-solidstate ionic conductors for achieving high-performance LIBs.

关键词： lithium ion batteries(LIBs) covalent organic frameworks(COFs) solid-state ion conductors solid-state electrolytes ion conductivity

Two intestinal microbiota-derived metabolites, deoxycholic acid and butyrate, synergize to enhance host defense peptide synthesis and alleviate necrotic enteritis

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Journal of Animal Science and Biotechnology 2024年第3期15卷 1158-1172页

作者： Dohyung m.Kim Jing liu melanie A.Whitmore Isabel Tobin Zijun Zhao Guolong Zhang Department of Animal and Food Sciences Oklahoma State UniversityStillwaterOKUSA

Background Necrotic enteritis(NE)is a major enteric disease in poultry,yet effective mitigation strategies remain *** acid(DCA)and butyrate,two major metabolites derived from the intestinal microbiota,have independently been shown to induce host defense peptide(HDP)***,the potential synergy between these two compounds remains *** To investigate the possible synergistic effect between DCA and butyrate in regulating HDP synthesis and barrier function,we treated chicken HD11 macrophage cells and jejunal explants with DCA and sodium butyrate(NaB),either individually or in combination,for 24 ***,we performed RNA isolation and reverse transcrip-tion-quantitative PCR to analyze HDP genes as well as the major genes associated with barrier *** further determine the synergy between DCA and NaB in enhancing NE resistance,we conducted two independent trials with Cobb broiler *** each trial,the diet was supplemented with DCA or NaB on the day-of-hatch,followed by NE induction through sequential challenges with Eimeria maxima and Clostridium perfringens on d 10 and 14,*** recorded animal mortality after infection and assessed intestinal lesions on d *** impact of DCA and NaB on the microbiota in the ileum and cecum was evaluated through bacterial 16S rRNA gene *** We found that the combination of DCA and NaB synergistically induced multiple HDP genes in both chicken HD11 cells and jejunal ***,the gene for claudin-1,a major tight junction protein,also exhibited synergistic induction in response to DCA and ***,dietary supplementation with a combination of 0.75 g/kg DCA and 1 g/kg NaB led to a significant improvement in animal survival and a reduction in intestinal lesions compared to either compound alone in a chicken model of ***,the cecal microbiota of NE-infected chickens showed a marked decrease in SCFA-producing bacteria such as Bacteroides,F

关键词： Bile acids Host defense peptides metabolites microbiome Necrotic enteritis Short-chain fatty acids

Identification of the optimal doping position of hetero-atoms in chalcogen-doped Fe-N-C catalysts for oxygen reduction reaction

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Particuology 2024年第6期89卷 99-108页

作者： Weihao liu Huanhuan He Qingtao liu Xin Wan Jianglan Shui School of materials Science and Engineering Beihang UniversityBeijing100191China School of Space and Environment Beihang UniversityBeijing102206China Tianmushan Laboratory Hangzhou310023China

The excellent oxygen reduction reaction(ORR)activity of Fe–N–C catalysts in acidic media makes them potential for low-cost proton exchange membrane fuel *** recent years,it has been shown that heteroatoms(B,O,S,P,Cl,F,etc.)can be used as electron-withdrawing groups to modulate the planar structure and electron distribution of the Fe–Nx active sites to achieve simultaneous improvement of catalytic activity and ***,the optimal location of the heteroatoms remains ***,taking chalcogen heteroatoms(S and Se)as an example,we control the doping positions and investigate their effect on the ORR performance of the Fe–N–C *** first coordination shell of the iron single atom is identified as the optimal doping *** optimized catalysts Fe–N_(3)Se_(1)/NC and Fe–N_(3)Se_(1)/NC demonstrate improved activity and stability in both half cells and fuel *** work provides insights into the enhancement mechanism of heteroatom doping in single-atom catalysts.

关键词： Oxygen reduction reaction Fe-N-C catalysts Hetero-atom doping Doping position Enhancement mechanism

Bioinspired 4D Printing Shape-memory Polyurethane Rhinoplasty Prosthesis for Dynamic Aesthetic Adjustment

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Journal of Bionic Engineering 2024年第3期21卷 1397-1411页

作者： Jiaqi liu Guiwei Li He liu Jincheng Wang Hui Wang Xue Gao Qingping liu Chenyu Wang Department of Plastic and Reconstructive Surgery The First Hospital of Jilin UniversityChangchun130021China Department of Orthopaedics The Second Hospital of Jilin UniversityChangchun130041China Key Laboratory of Bionic Engineering(ministry of Education) Jilin UniversityChangchun130022China

The disparity between the postoperative outcomes of rhinoplasty and the expected results frequently necessitates secondary or multiple surgeries as a compensatory measure,greatly diminishing patient ***,there is renewed optimism for addressing these challenges through the innovative realm of Four-Dimensional(4D)*** groundbreaking technology enables three-dimensional objects with shape-memory properties to undergo predictable transformations under specific external ***,implants crafted using 4D printing offer significant potential for dynamic *** by worms in our research,we harnessed 4D printing to fabricate a Shape-memory Polyurethane(SmPU)for use as a nasal augmentation *** choice of SmPU was guided by its Glass Transition Temperature(Tg),which falls within the acceptable temperature range for the human *** attribute allowed for temperature-responsive intraoperative self-deformation and postoperative *** chosen animal model for experimentation was *** into account the anatomical structure of the rabbit nose,we designed and produced nasal augmentation prostheses with superior *** prostheses were then surgically implanted in a minimally invasive manner into the rabbit ***,they exhibited successful temperature-controlled in-surgery self-deformation according to the predetermined shape and non-invasive remodeling within a mere 9 days *** histological evaluations confirmed the practical viability of these prostheses in a living *** research findings posit that worm-inspired 4D-printed SmPU nasal prostheses hold significant promise for achieving dynamic aesthetic adjustments.

关键词： 4D printing Shape memory polyurethane Rhinoplasty Self-deformation Dynamic aesthetic adjustment

Unlocking high-efficiency oxygen evolution reaction through Co-N coordination engineering in Co@N-doped porous carbon core–shell nanoparticles

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Nano Research 2024年第8期17卷 7068-7076页

作者： Shucheng liu Yu Shuai Xiaosi Qi Zhao Ding Yi liu College of Big Data and Information Engineering Guizhou UniversityGuiyang 550025China College of Physics Guizhou Province Key Laboratory for Photoelectrics Technology and ApplicationGuizhou UniversityGuiyang 550025China

modulation of metal sites coordination can significantly refine the electronic architecture of catalysts,thereby improving their catalytic *** work successfully developed a core–shell Co@N-doped porous carbon(Co@NC)catalyst by pyrolyzing the COF/mOF(IISERP-COF3/ZIF-67)composite in an inert *** Co@NC catalyst exhibited impressive oxygen evolution reaction(OER)performance,with a small overpotential of 304 mV and a modest Tafel slope of 88.6 mV·dec^(−1) in a 1 m KOH,alongside remarkable stability,maintaining 98.5%of its activity over 13 *** role of IISERP-COF3 was pivotal in preventing Co atom aggregation during the ZIF-67 pyrolysis,which facilitated the creation of mesopores for enhanced mass transport and ***,it effectively modulated the Co-N coordination to fine-tune the electronic structure,thereby optimizing the catalyst's capacity for adsorption of intermediates and boosting its intrinsic *** functional theory(DFT)studies corroborate that the exceptional OER efficiency of Co@NC can be linked to the enhanced Co-N coordination,optimizing the localized electronic structure at the Co active *** study not only proposes an innovative approach for optimizing COF/mOF as effective electrocatalysts but also clears the path for the emergence of affordable,high-performance alternatives to precious metal-based catalysts,marking a significant advancement in sustainable energy technologies.

关键词： covalent organic framework(COF) metal-organic framework(mOF) core-shell structure catalysts oxygen evolution reaction