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Interconnected microstructure and flexural behavior of Ti_(2)C-Ti composites with superior Young’s modulus

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International Journal of Minerals,Metallurgy and Materials 2024年第9期31卷 2088-2101页

作者： Fengbo Sun Rui Zhang Fanchao meng shuai wang Lujun Huang Lin Geng School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China Waikato Centre for Advanced Materials and Manufacturing School of EngineeringUniversity of WaikatoHamilton 3240New Zealand State Key Laboratory of Precision Welding&Joining of Materials and Structures Harbin Institute of TechnologyHarbin 150001China

To enhance the Young’s modulus(E)and strength of titanium alloys,we designed titanium matrix composites with intercon-nected microstructure based on the Hashin-Shtrikman *** to the results,the in-situ reaction yielded an interconnected microstructure composed of Ti_(2)C particles when the Ti_(2)C content reached 50vol%.With widths of 10 and 230 nm,the intraparticle Ti lamellae in the prepared composite exhibited a bimodal size distribution due to precipitation and the unreacted Ti phase within the grown Ti_(2)C *** composites with interconnected microstructure attained superior properties,including E of 174.3 GPa and ultimate flexural strength of 1014 *** with that of pure Ti,the E of the composite was increased by 55% due to the high Ti_(2)C content and interconnected *** outstanding strength resulted from the strong interfacial bonding,load-bearing capacity of interconnected Ti_(2)C particles,and bimodal intraparticle Ti lamellae,which minimized the average crack driving *** flexural tests revealed preferential crack initiation along the{001}cleavage plane and grain boundary of Ti_(2)C in the region with the highest tensile *** addition,the propagation can be efficiently inhibited by interparticle Ti grains,which prevented the brittle fracture of the composites.

关键词： titanium matrix composites titanium carbide interface Young’s modulus flexural behavior

Fatigue Crack Initiation and Propagation Dominated by Crystallographic Factors in TiB/near α-Ti Composite

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Acta Metallurgica Sinica(English Letters) 2024年第5期37卷 763-776页

作者： Fanchao meng Rui Zhang shuai wang Fengbo Sun Run Chen Lujun Huang Lin Geng School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China Waikato Centre for Advanced Materials and Manufacturing School of EngineeringUniversity of WaikatoHamilton 3240New Zealand State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China

Discontinuously reinforced titanium matrix composites(DRTMCs)with a network structure have been extensively researched due to their superior combination of strength and ***,their fatigue performance has remained *** order to elucidate the fatigue behavior of DRTMCs,a tension-tension fatigue test was performed on a TiB/nearα-Ti composite with network *** results showed that the variability of fatigue lifetime increased as the stress level *** analysis indicated that fatigue crack initiation was associated with facet formation,while the subsequent propagation was hindered by the network structure comprising TiB whiskers and *** characterization further revealed that facets formed due to a combination of shear and normal *** reduction in fatigue lifetime was attributed to an increase in the effective slip length,which was influenced by the orientation of grains near the crack-initiation sites toward basal slip in the life-limiting *** in situ observation suggested that the crack initiation was facilitated by both basal and prismatic slip ofα-Ti as well as fracture of *** propagation was found to be associated with basal and prismatic slip systems with high Schmid factors,regardless of whether the crack was intergranular or intragranular.

关键词： Titanium matrix composite TiBw Fatigue lifetime variability Crack initiation Crack propagation

Hot deformation behavior and microstructure evolution of GH3536-TiB_(2) composites fabricated by powder metallurgy

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Science China(Technological Sciences) 2024年第7期67卷 2107-2124页

作者： ZHOU ShiPeng wang shuai HUANG LuJun ZHANG Rui CHEN Xin meng FanChao CHEN Run SUN FengBo wang CunYu GENG Lin School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China Waikato Centre for Advanced Materials and Manufacturing School of EngineeringUniversity of WaikatoHamilton 3240New Zealand State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China

The hot deformation behavior and microstructure evolution of GH3536-TiB2composites fabricated by powder metallurgy(PM)were examined in the temperature range of 950–1150℃ and strain rate range of 0.001–1 s^(-1). The hot compression stress-strain curves and the constitutive equation were obtained. In addition, the hot processing map was drawn, which indicated that the appropriate hot working window was 950–1050℃/0.001–0.1 s^(-1)and 1050–1100℃/0.001–0.01 s^(-1). The microstructure analysis showed that the splitting and spheroidization of M3B2led to a decrease in size and volume fraction at 950–1100℃. At 1150℃,the eutectic microstructure of M_(3)B_(2)+ γ was formed due to the dissolution of M_(3)B_(2), which caused macroscopic cracking of the deformed sample. Additionally, the deformation temperature and the strain rate had little effect on the size and volume fraction of M_(3)B_(2). Besides, discontinuous dynamic recrystallization(DDRX) and continuous dynamic recrystallization(CDRX) were found in the deformed microstructure, while the former was dominant. Within the test range of this work, the dynamic recrystallization(DRX) fraction of the deformed composites was high due to the bulging nucleation of numerous interfaces. The DRX grain size increased with increasing deformation temperature or decreasing strain rate. Texture analysis showed that the deformation texture of //compression direction RD existed in the matrix when the deformation temperature was below 1100℃, and the texture type became //RD at 1100℃. Additionally, it was also found that the //RD texture was formed in M3B2under the strain rates of 0.1 and 0.01 s^(-1).

关键词： GH3536 alloy matrix composites powder metallurgy hot deformation behavior microstructure evolution

Spatio-Temporal Service Analysis in Multi-Layer Non-Terrestrial Networks

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Journal of Communications and Information Networks 2024年第1期9卷 43-55页

作者： Qian Chen Weixiao meng shuai Han Cheng Li School of Electronics and Information Engineering Harbin Institute of TechnologyHarbin 150001China School of Engineering Science Simon Fraser UniversityBurnabyBC V5A 1S6Canada Department of Electrical and Computer Engineering Memorial UniversitySt.John’sNL A1B 3X5Canada

In the advent of the 6G era, non-terrestrial networks (NTN) with expansive coverage are being increasingly recognized as a vital supplement to cellular networks for facilitating seamless communication. The intricate interplay between network performance and service quality necessitates a thorough investigation into the modeling and analysis of services for efficient construction of *** studies on service analysis, predominantly focused on terrestrial networks,fall short in addressing the unique challenges posed by NTN,particularly those related to platform distribution and antenna gain modeling. This deficiency in research,coupled with the varying preferences of users for different network types, forms the basis of this study. This paper explores the spatio-temporal characteristics of services within a multi-layered NTN *** this context,the spatial distribution of the platforms is modeled using a binomial point process, and the antennas are characterized by a sectorized beam pattern. We derive the closed-form expressions for the association probability,the number of accessed users, and the arrival rate of services with certain delay requirements towards different types of NTN. Simulation results are provided to evaluate the influence of various parameters on the association probability, the number of accessed users, and the total arrival rate of services. The number of satellites can be determined to achieve the optimal system utility,balancing the accessed services, offloading effects, and launching costs. This initial investigation lays the groundwork for further theoretical progress in the service analysis and platform deployment of NTN.

关键词： association strategy non-terrestrial networks service analysis stochastic geometry system utility

Generation and Tunable Focal Shift of the Hybridly Polarized Vector Optical Fields with Parabolic Symmetry

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Chinese Physics Letters 2020年第12期37卷 36-40页

作者： Xu-Zhen Gao meng-shuai wang Jia-Hao Zhao Peng-Cheng Zhao Xia Zhang Yue Pan Yongnan Li Chenghou Tu Hui-Tian wang School of Physics and Physical Engineering Shandong Provincial Key Laboratory of Laser Polarization and Information TechnologyQufu Normal UniversityQufu 273165China School of Physics and Key Laboratory of Weak-Light Nonlinear Photonics Nankai UniversityTianjin 300071China National Laboratory of Solid State Microstructures and School of Physics Nanjing UniversityNanjing 210093China Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China

Based on a parabolic coordinate system,we theoretically design and experimentally generate hybridly polarized vector optical fields with parabolic symmetry of the first and second kinds,which can further enrich the family of vector optical *** wavefront of this new-kind vector optical field contains circular,elliptic and linear polarizations,and the polarizations can keep the same or change along the parabolic *** we present the realization of tunable focal shift with the hybridly polarized vector optical field,and show a specific law of the focal shift of the focused hybridly polarized vector optical field with the parabolic *** hope these results can provide a new way to flexibly modulate focal fields,which can be applied in realms such as optical machining,optical trapping and information transmission.

关键词： parabolic polarized realization

Clinical relevance of distolingual roots and periodontal status in mandibular first molars: a cross-sectional study employing CBCT analysis

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2024年第3期25卷 244-253页

作者： Feifei MAO meng wang shuai ZHOU Yan ZHAO Jiaping HUANG Fengying YIN Haiping YANG Pei-hui DING Stomatology Hospital School of StomatologyZhejiang University School of MedicineZhejiang Provincial Clinical Research Center for Oral DiseasesKey Laboratory of Oral Biomedical Research of Zhejiang ProvinceCancer Center of Zhejiang UniversityHangzhou 310016China

Objectives:Distolingual root of the permanent mandibular first molar(PMFM-DLR)has been frequently reported,which may complicate the treatment of *** study aimed to assess the morphological features of PMFM-DLR and investigate the correlation between the morphological features of PMFM-DLR and periodontal status in patients with Eastern Chinese ethnic *** and methods:A total of 836 cone beam computed tomography(CBCT)images with 1497 mandibular first molars were analyzed to observe the prevalence of PMFM-DLR at the patients and tooth levels in Eastern *** them,complete periodontal charts were available for 69 Chinese patients with 103 *** and regression analyses were used to evaluate the correlation between the morphological features of DLR,bone loss,and periodontal clinical parameters,including clinical attachment loss(CAL),probing pocket depth(PPD),gingival recession(GR),and furcation involvement(FI).Results:The patient-level prevalence and tooth-level prevalence of DLR in mandibular first molars were 29.4%and 26.3%,*** linear regression analysis suggested that bone loss at the lingual site and CAL were negatively affected by the angle of separation between distolingual and mesial roots in the transverse section,while they were significantly influenced by age and the angle of separation between distobuccal and mesial roots in the coronal ***:The prevalence of PMFM-DLR in Eastern China was relatively high in our *** morphological features of DLR were correlated with the periodontal status of mandibular first *** study provides critical information on the morphological features of DLR for improved diagnosis and treatment options of mandibular molars with DLR.

关键词： Distolingual root Mandibular first molar Periodontal clinical parameter Clinical attachment loss Cone beam computed tomography(CBCT)

Exciting broadband thermochromic transmission property opposite to vanadium dioxide in the atmospheric window

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Science China(Technological Sciences) 2024年第7期67卷 2244-2254页

作者： GONG YiQuan GUO YanMing CHEN ShuNi LI meng PAN QingHui shuai Yong Ministry of Industry and Information Technology Key Laboratory of Aerospace Thermophysics School of Energy Science and EngineeringHarbin Institute of TechnologyHarbin 150001China

The traditional telecommunications band performs poorly in harsh weather conditions due to atmospheric absorption. In recent years, researchers have begun to study optical communication through atmospheric windows, and optical switches are an essential component of optical communication. A broadband atmospheric window optical switch was proposed based on Vanadium dioxide and magnetic polaritons(MP). It is formed by the stacking of two metal-dielectric-metal structures. The simulation results show that the modulation depth can reach 98.38%, and the extinction ratio is 17.93 dB. By calculating the magnetic field, we confirmed that the reason for the “off” mode is the coupling between the different MP modes, while the “on”mode is the excitation of MP. The optical switch we proposed may be applied to radiation cooling and optical satellite communication.

关键词： optical communication thermochromic property atmospheric window optical switch magnetic polariton

Photocatalytic transformation of selected biomass derivatives to value added chemicals and hydrogen fuel

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Chinese Chemical Letters 2024年第3期35卷 19-26页

作者： Xiangjun Liu shuai Zhang Miao wang Junqi wang School of Human Settlements and Civil Engineering Xi'an Jiaotong UniversityXi'an 710049China

Biomass is the most bountiful renewable carbon resource on *** transformation is a promising method to utilize biomass to obtain high-value-added chemicals and it has more obvious advantages compared with thermochemical and biological processes due to the milder operational conditions,fewer reagents and *** material is one of the most common kinds of heterogeneous biomass photocatalysts,which has the advantages of high selectivity,stable catalytic performance,long activation time,and low *** this paper,the significant research progress on the photocatalytic transformation of biomass with semiconductor materials to produce high-value-added chemicals is reviewed,and the three most typical semiconductor photocatalysts(TiO_(2),Cd S,and g-C_(3)N_(4))are *** photocatalytic mechanism and photocatalytic system optimization including structural modification,metal co-catalyst loading,and introduction of heterojunction are ***,the main problems,the development direction and trend of semiconductor materials in photocatalytic transformations of biomass in the future are prospected,which provide guidance and inspiration for the further development of semiconductor photocatalysts and make contributions to the progress in efficient utilization of biomass.

关键词： Photocatalytic transformation Biomass Semiconductor material H_(2) High value-added chemical

DCEL:classifier fusion model for Android malware detection

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Journal of Systems Engineering and Electronics 2024年第1期35卷 163-177页

作者： XU Xiaolong JIANG shuai ZHAO Jinbo wang Xinheng Jiangsu Key Laboratory of Big Data Security&Intelligent Processing Nanjing University of Posts and TelecommunicationsNanjing 210023China School of Computer Science Nanjing University of Posts and TelecommunicationsNanjing 210023China School of Computing and Engineering University of West LondonLondon W55RFUK

The rapid growth of mobile applications,the popularity of the Android system and its openness have attracted many hackers and even criminals,who are creating lots of Android ***,the current methods of Android malware detection need a lot of time in the feature engineering ***,these models have the defects of low detection rate,high complexity,and poor practicability,*** analyze the Android malware samples,and the distribution of malware and benign software in application programming interface(API)calls,permissions,and other *** classify the software’s threat levels based on the correlation of ***,we propose deep neural networks and convolutional neural networks with ensemble learning(DCEL),a new classifier fusion model for Android malware ***,DCEL preprocesses the malware data to remove redundant data,and converts the one-dimensional data into a two-dimensional gray ***,the ensemble learning approach is used to combine the deep neural network with the convolutional neural network,and the final classification results are obtained by voting on the prediction of each single *** based on the Drebin and Malgenome datasets show that compared with current state-of-art models,the proposed DCEL has a higher detection rate,higher recall rate,and lower computational cost.

关键词： Android malware detection deep learning ensemble learning model fusion