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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

IN SITU mETALLOGRAPHIC OBSERVAION OF THERmALCYCLING EFFECTS ON PHASE TRANSFORmATION IN Cu-Zn-Al SHAPE mEmORY ALLOY

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Acta metallurgica Sinica(English Letters) 1997年第3期10卷 157-165页

作者： m liu X.m Zhang m.Z. liuand R.S. liu(metal material Department, Sichuan Union University, Chengdu 610065, China) (Institute of metal Research, Chinese Academy of Sciences, Shenyang 110015, China)

In this paper, an in situ metallographic video system was used to study the morphology in Cu-Zn-Al shape memory alloy (SmA) during thermal cycling phase tmnsforma-tion. There are seven different types of martensite morphology in Cu-Zn-Al SmA,i.e. plate, spean bamboo, noose, round-spot, line and dot-like martensites. During transformation and inverse-transformation, the thermoelastic martensites were rising and falling, growing and shrinking, splitting and merping. The growth patterns of thermoelastic martensite were divided into three types: fast growing, very slow ex-pansion and uniform automatic growth. Automatic growth appeared when ageing at a temperature below ms. The result, for the first time, coofirmed Olson and Cohen,s suggestion that thermoelastic martensite may be automatically grown when ageing be-low ms. With increasing numbers of thermal cycling, both the memory recovery ratio (% )and memory recoverp degradation (%) degraded logarithmically. The degrada-tion was steep in the initial stage and then became more and more gradual in the middle and the final stages caused by the stabilisation of martensite. In the initial stage, vacancies assumed the controlling role, while dislocations took the major role in other stages. The martensite transformation caused the intedeces to become bent and blurmd, but with increasing cycling numbers, the movements of interface had the same degradation effects as the memory recovery ratio curves. Under these conditions, we also found the martensites on one side of the intedece became reorientated and par-allel to the intedece. It was therefore concluded that the movement degradation of the interface and the appearance of bamboo like martensite induced the degradation of two way shape memory effect (TWmP).

关键词： in situ metallographic video study thermal cycling phase trans-formation the degradation of TWmE

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

Accuracy of LA-ICPmS zircon U-Pb age determination:An inter-laboratory comparison

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Science China Earth Sciences 2015年第9期58卷 1722-1730页

作者： LI XianHua liu Xiaoming liu YongSheng SU Li SUN WeiDong HUANG HuiQing YI Keewook State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences State Key Laboratory of Continental Dynamics Department of Geology Northwest University State Key Laboratory of Geological Processes and mineral Resources Faculty of Earth Sciences China University of Geosciences Geological Lab Center China University of GeosciencesBeijing State Key Laboratory of Isotope Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences NSW Institute of Frontiers Geoscience School of Environmental and Life Sciences University of Newcastle University Drive Korea Basic Science Institute

LA-ICPmS zircon U-Pb dating has been greatly advanced and widely applied in the past decade because it is a cheap and fast *** internal error of LA-ICPmS zircon U-Pb dating can be better than 1%,but reproducibility(accuracy)is relatively *** order to quantitatively assess the accuracy of this technique,zircons from two dioritic rocks,a mesozoic dioritic microgranular enclave(FS06)and a Neoproterozoic diorite(WC09-32),were dated independently in eight laboratories using SImS and *** of three SImS analyses on FS06 and WC09-2 are indistinguishable within error and give a best estimate of the crystallization age of 132.2 and 760.5 ma(reproducibility is^1%,2RSD),*** U-Pb ages determined by LA-ICPmS in six laboratories vary from 128.3±1.0 to 135.0±0.9 ma(2SE)for FS06 and from 742.9±3.1 to777.8±4.7 ma(2SE)for WC09-32,suggesting a reproducibility of^4%(2RSD).Uncertainty produced during LA-ICPmS zircon U-Pb analyses comes from multiple sources,including uncertainty in the isotopic ratio measurements,uncertainty in the fractionation factor calculation using an external standard,uncertainty in the age determination as a result of common lead correction,age uncertainty of the external standards and uncertainty in the data *** of our study suggests that the uncertainty of LA-ICPmS zircon U-Pb dating is approximately 4%(2RSD).The uncertainty in age determination must be considered in order to interpret LA-ICPmS zircon U-Pb data rationally.

关键词： zircon U-Pb dating Laser ablation-inductively coupled plasma mass spectrometry (LA-ICPmS) Secondary ion massspectrometry (SImS) accuracy precision

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

Design and performance investigation of modified dual reflector parabolic trough collector with double planar mirrors

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Science China(Technological Sciences) 2024年第3期67卷 902-918页

作者： LI Peijing liu TaiXiu QIN YuanLong LI JiChao liu QiBin School of Energy Powerand Mechanical EngineeringNorth China Electric Power University Beijing 226China Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Department of Thermal Science and Energy Engineering University of Science and Technology of ChinaHefei 230027China

In a typical parabolic trough collector(PTC), sunlight is concentrated at the bottom of the absorber tube. This concentrated solar flux leads to uneven heat distribution, resulting in high local temperatures and significant thermal stress on the absorber *** limitations have restricted the application of PTCs in solar thermochemistry and other fields and have impacted their safe operation. In this study, a new PTC with dual planar mirrors(DPmS) is proposed to homogenize the circumferential solar flux distribution of the absorber tube. A design method and single-objective optimization of the new PTC with a DPmS are proposed,and an uncertainty analysis of the operational and structural parameters is performed. A coupled light-heat-structure numerical model was developed to study the heat transfer performance and structural mechanical properties. The thermodynamic properties of the PTC with DPmS under different boundary conditions were analyzed. The results show that the circumferential temperature difference of the new PTC is within 2.6 K, and the circumferential thermal deformation is within 0.9 mm under typical working conditions(the inlet velocity of the heat transfer fluid is 3 m/s, inlet temperature is 573.15 K, and the direct normal irradiance is 1000 W/m^(2)). Compared with conventional PTCs, the circumferential temperature difference is reduced by 74%–90%, and the maximum thermal deformation along the y-axis is reduced by more than 95% under all working conditions(1–5 m/s, 373.5–675.15 K, 200–1000 W/m^(2)). The new PTC maintains the uniformity of the circumferential solar flux distribution for different operating parameters(sun incident angle of 0°–3°) and installation errors(±3 mm), is suitable for solar energy applications in various fields, and has the potential for large-scale applications.

关键词： solar thermal energy parabolic trough collector secondary reflector solar flux distribution optical optimization