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Indoor Uncertain Semantic Trajectory Similarity Join

Journal of Computer Science & Technology 2024年第6期39卷 1441-1465页

作者： Hong-Bo Yin Dong-Hua Yang Kai-Qi Zhang Hong Gao Jian-Zhong Li Faculty of Computing Harbin Institute of TechnologyHarbin 150001China Center of Analysis Measurement and ComputingHarbin Institute of TechnologyHarbin 150001China Faculty of Computer Science and Control Engineering Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China

With the widespread deployment of indoor positioning systems, an unprecedented scale of indoor trajectories is being produced. By considering the inherent uncertainties and the text information contained in such an indoor trajectory, a new definition named Indoor Uncertain Semantic Trajectory is defined in this paper. In this paper, we focus on a new primitive, yet quite essential query named Indoor Uncertain Semantic Trajectory Similarity Join (IUST-Join for short), which is to match all similar pairs of indoor uncertain semantic trajectories from two sets. IUST-Join targets a number of essential indoor applications. With these applications in mind, we provide a purposeful definition of an indoor uncertain semantic trajectory similarity metric named IUS. To process IUST-Join more efficiently, both an inverted index on indoor uncertain semantic trajectories named 3IST and the first acceleration strategy are proposed to form a filtering-and-verification framework, where most invalid pairs of indoor uncertain semantic trajectories are pruned at quite low computation cost. And based on this filtering-and-verification framework, we present a highly-efficient algorithm named Indoor Uncertain Semantic Trajectory Similarity Join Processing (USP for short). In addition, lots of novel and effective acceleration strategies are proposed and embedded in the USP algorithm. Thanks to these techniques, both the time complexity and the time overhead of the USP algorithm are further reduced. The results of extensive experiments demonstrate the superior performance of the proposed work.

关键词： filtering-and-verification framework indoor uncertain semantic trajectory inverted index trajectory similarity join

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Refined microstructure and enhanced mechanical properties of AlCrFe_(2)Ni_(2) medium entropy alloy produced via laser remelting

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Journal of Materials Science & Technology 2022年第4期99卷 18-27页

作者： Tianyi Han Yong Liu Mingqing Liao Danni Yang Nan Qu Zhonghong Lai Jingchuan Zhu School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of TechnologyHarbin 150001China Center of Analysis and Measurement and Computing Harbin Institute of TechnologyHarbin 150001China

A Co-free as-cast AlCrAlCrFe_(2)Ni_(2)medium entropy alloy(MEA)with multi-phases was remelted by fiber laser in this *** effect of laser remelting on the microstructure,phase distribution and mechanical properties was investigated by characterizing the as-cast and the remelted AlCrAlCrFe_(2)Ni_(2)*** laser remelting process resulted in a significant decrease of grain size from about 780μm to 58.89μm(longitudinal section)and 15.87μm(transverse section)and an increase of hardness from 4.72±0.293 GPa to 6.40±0.147 GPa(longitudinal section)and 7.55±0.360 GPa(transverse section).It was also found that the long side plate-like microstructure composed of FCC phase,ordered B2 phase and disordered BCC phase in the as-cast alloy was transformed into nano-size weave-like microstructure consisting of alternating ordered B2 and disordered BCC *** mechanical properties were evaluated by the derived stressstrain relationship obtained from nano-indentation tests *** results showed that the yield stress increased from 661.9 MPa to 1347.6 MPa(longitudinal section)and 1647.2 MPa(transverse section)after *** individual contribution of four potential strengthening mechanisms to the yield strength of the remelted alloy was quantitatively evaluated,including grain boundary strengthening,dislocation strengthening,solid solution strengthening and precipitation *** calculation results indicated that dislocation and precipitation are dominant strengthening mechanisms in the laser remelted MEA.

关键词： Medium entropy alloy Laser remelting Microstructure Nano-indentation Strengthening mechanism

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Beneficial effects of deep cryogenic treatment on mechanical properties of additively manufactured high entropy alloy:cyclic vs single cryogenic cooling

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Journal of Materials Science & Technology 2022年第20期115卷 40-51页

作者： Hongge Li Wenjie Zhao Tian Chen Yongjiang Huang Jianfei Sun Ping Zhu Yunzhuo Lu Alfonso H.W.Ngan Daqing Wei Qing Du Yongchun Zou School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China School of Materials Science and Engineering Dalian Jiaotong UniversityDalian 116028China Department of Mechanical Engineering The University of Hong KongHong KongChina Center of Analysis Measurement and Computing Harbin Institute of TechnologyHarbin 150001China

Additively manufactured(AM)metallic materials commonly possess substantial tensile surface residual stress,which is detrimental to the load-bearing service ***,we demonstrated that deep cryogenic treatment(DCT)is an effective method for improving the tensile properties of CoCrFeMnNi high-entropy alloy(HEA)samples fabricated by laser melting deposition(LMD),by introducing high compressive residual stress and deformation microstructures without destroying the AM ***,carrying out the DCT in a single-step mode does not improve the residual stress gradients inherent from the LMD process,which are undesirable as the mechanical properties will not be homogeneous within the *** this work,we show that carrying out the DCT in a cyclic mode with repeated cryogenic cooling and reheating can significantly homogenize the residual stress in LMD-fabricated Co Cr Fe Mn Ni HEA,and improve tensile strength and ductility,compared with single-step DCT of the same cryogenic soaking *** cyclic DCT,the thermal stress is re-elevated to a high value at each cryogenic cooling step,leading to the formation of denser and more intersecting reinforcing crystalline defects and hcp phase transformation,compared to single-step DCT of the same total cryogenic soaking duration in which the thermal stress relaxes towards a low value over *** enhancement of defect formation in the cyclic mode of DCT also leads to more uniform residual stress distribution in the sample after the *** results here provide important insights on optimizing DCT processes for post-fabrication improvement of mechanical properties of AM metallic net shapes.

关键词： Additive manufacturing High entropy alloy Deep cryogenic treatment Residual stress Mechanical properties

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A new strategy for fabrication of unique heterostructured titanium laminates and visually tracking their synchronous evolution of strain partitions versus microstructure

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Journal of Materials Science & Technology 2022年第12期107卷 70-81页

作者： Hao Ding Xiping Cui Zhiqi Wang Tao Zhao Yuchen Wang Yuanyuan Zhang Hongtao Chen Lujun Huang Lin Geng Junfeng Chen School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China Center for Analysis Measurement and ComputingHarbin Institute of TechnologyHarbin 150001China School of Materials Science and Engineering Harbin University of Science and TechnologyHarbin 150080China School of Materials Science and Engineering Fuzhou UniversityFuzhou 350116China

Heterostructured(HS)material with extraordinary mechanical properties has been regarded as one of the most promising structural ***,we reported a new strategy for preparing heterostructured pure titanium laminates that possess a good combination of strength and ductility by combining gradient structure(GS)and heterogeneous lamella structure(HLS).The deformation characteristic versus microstructure evolution of GS/HLS titanium laminates,namely the strain partitions between different-sized grains(480–25μm)was visualized using a scanning electron microscope(SEM)equipped with electron backscattered diffraction(EBSD)mode combined with the digital image correlation(SEM-DIC)with an ultrahigh spatial resolution for the first *** a result,the hetero-deformation of unique GS/HLS structure by the characteristic of strain partitions could be accurately *** the hetero-deformation could result in the hetero-deformation induced(HDI)stress strengthening and HDI hardening,which were regarded as the key reason that the resulting GS/HLS Ti laminates showed a superior combination of strength and *** could promote a more in-depth understanding of the strengtheningtoughening mechanism of heterostructured material.

关键词： Gradient structure Heterogeneous lamella structure Digital image correlation Strain partition

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Relating microstructure to magnetocaloric properties in RE_(36)Tb_(20)Co_(20)Al_(24)(RE=Gd,Dy or Ho)high-entropy metallic-glass microwires designed by binary eutectic clusters method

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Journal of Materials Science & Technology 2023年第18期149卷 167-176页

作者： Hangboce Yin Jun-Qiang Wang Yongjiang Huang Hongxian Shen Shu Guo Hongbo Fan Juntao Huo Jianfei Sun School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China CAS Key Laboratory of Magnetic Materials and Devices and Zhejiang Province Key Laboratory of Magnetic Materials and Application TechnologyNingbo Institute of Materials Technology&EngineeringChinese Academy of SciencesNingbo 315201China Center for Analysis Measurement and Computing Harbin Institute of TechnologyHarbin 150001China Space Environment Simulation Research Infrastructure Harbin Institute of TechnologyHarbin 150001China

The new high-entropy metallic-glasses(HE-MGs)are designed by using Dy and Ho to replace Gd in Gd_(36)Tb_(20)Co_(20)Al_(24)alloy based on the binary eutectic clusters *** with the equiatomic Gd 25 Tb 25 Co 25 Al 25 HE-MG,the non-equiatomic RE_(36)Tb_(20)Co_(20)Al_(24)(RE=Gd,Dy,or Ho)alloys show bet-ter glass-forming ability,which is attributed to the deep binary eutectic compositions used for alloy *** RE_(36)Tb_(20)Co_(20)Al_(24)alloys undergo second-order magnetic *** extreme peak value of magnetic entropy change is obtained as 10.3 J kg^(-1) K-1(5 T)for the Ho_(36)Tb_(20)Co_(20)Al_(24)***-situ high-energy synchrotron X-ray diffraction was conducted to observe the microstructural difference among non-equiatomic samples at cryogenic *** results indicate that Gd_(36)Tb_(20)Co_(20)Al_(24)alloy possesses a relatively large average value of the dispersion of local clusters at a low-temperature ***,com-bined with the critical exponentβclose to 0.5 of Gd_(36)Tb_(20)Co_(20)Al_(24)alloy,leads to its widest working temperature span among non-equiatomic *** work successfully establishes the connection be-tween microstructure and magnetocaloric properties of HE-MGs,which is beneficial for understanding the physical mechanism of the magnetocaloric behaviors of HE-MGs.

关键词： High-entropy metallic-glass Magnetocaloric effect High energy synchrotron X-ray diffraction Cryogenic temperature

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Study on the Microstructure of SiC Ceramic Joint Bonding by CaO-Al2O3 Glass-ceramic Solder 6

Study on the Microstructure of SiC Ceramic Joint Bonding by ...

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6th International Conference on Mechanical, Electrical and Material Application, MEMA 2023

作者： Liu, Wei Lu, Yongheng Shao, Zongyi Meng, Ying Shan, Tipeng Sun, Liangbo China North Nuclear Fuel Co. Ltd. Baotou014030 China Cnnc Key Laboratory on Fabrication Technology of Reactor Irradiation Special Fuel Assembly Baotou014030 China Center of Analysis Measurement and Computing Harbin Institute of Technology Harbin150001 China

In this paper, 49.77wt.% CaO-50.23wt.% Al2O3 (CA) glass has been designed, fabricated and studied for the joining of SiC ceramics. The thermophysical properties, crystallization kinetics, crystallization behavior of glass solder, and the microstructure of the joint were analyzed and discussed in detail. It is found that the melting point of CA glass solder is 1437 °C, the crystallization activation energy is 274.07 kJ/mol, and the precipitated crystal is 12CaO·7Al2O3. The minimum wetting angle of CA solder on pre-oxidized SiC ceramics is 23°. The joint interface is well combined, and two crystal phases of 2CaO·Al2O3·SiO2 and 12CaO·7Al2O3 are formed in the weld. The typical microstructure of a SiC ceramic joint with CA glass solder is SiC/2CaO·Al2O3·SiO2+12CaO·7Al2O3/SiC at 1550 °C for 10 min. © Published under licence by IOP Publishing Ltd.

关键词： Activation energy

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Heterostructured Mn_(3)O_(4)-MnS Multi-Shelled Hollow Spheres for Enhanced Polysulfide Regulation in Lithium-Sulfur Batteries

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Energy & Environmental Materials 2023年第6期6卷 436-444页

作者： Bin Qin Qun Wang Weiqi Yao Yifei Cai Yuhan Chen Pengcheng Wang Yongchun Zou Xiaohang Zheng Jian Cao Junlei Qi Wei Cai State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China College of Chemistry and Chemical Engineering Taiyuan University of TechnologyTaiyuan 030024China State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai 200237China Department of Mechanical Engineering City University of Hong KongHong KongChina Center of Analysis Measurement and Computing Harbin Institute of TechnologyHarbin 150001China School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001China

Constructing heterojunctions and hollow multi-shelled structures can render materials with fascinating physicochemical properties,and have been regarded as two promising strategies to overcome the severe shuttling and sluggish kinetics of polysulfide in lithium-sulfur(Li-S)***,a single strategy can only take limited *** catalytic hosts with synergistic effects are urgently ***,Mn_(3)O_(4)-MnS heterogeneous multi-shelled hollow spheres are meticulously designed by controlled sulfuration of Mn2O3 hollow spheres,and then applied as advanced encapsulation hosts for Li-S *** from the separated spatial confinement by hollow multi-shelled structure,ample exposed active sites and built-in electric field by heterogeneous interface,and synergistic effects between Mn_(3)O_(4)(strong adsorption)and MnS(fast conversion)components,the assembled battery achieves prominent rate capability and decent cyclability(0.016%decay per cycle at 2 C,1000 cycles).More crucially,satisfactory areal capacity reaches up to 7.1 mAh cm^(-2)even with high sulfur loading(8.0 mg cm^(-2))and lean electrolyte(E/S=4.0 pL mg^(-1))*** work will provide inspiration for the rational design of hollow multi-shelled heterostructure for various electrocatalysis applications.

关键词： electrocatalyst heterojunction host hollow multi-shelled structure Li-S battery Mn_(3)O_(4)-MnS

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Electronic structure and optical properties of non-metallic modified graphene:a first-principles study

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Communications in Theoretical Physics 2022年第3期74卷 70-76页

作者： Jing-tao Huang Yong Liu Zhong-hong Lai Jin Hu Fei Zhou Jing-chuan Zhu School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of TechnologyHarbin 150001China Center for analysis measurement and computingHarbin Institute of TechnologyHarbin 150001China MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin 150001China

In this paper,the electronic structure and stability of the intrinsic,B-,N-,Si-,S-doped graphene are studied based on first-principles calculations of density functional ***,the intrinsic,B-,N-,Si-,S-doped graphene structures are optimized,and then the forming energy,band structure,density of states,differential charge density are analyzed and *** results show that Band Si-doped systems are p-type doping,while N is n-type *** comparing the forming energy,it is found that N atoms are more easily doped in *** addition,for B-,N-,Si-doped systems,it is found that the doping atoms will open the band gap,leading to a great change in the band structure of the doping ***,we systematically study the optical properties of the different *** comparison,it is found that the order of light sensitivity in the visible region is as follows:S-doped>Si-doped>pure>B-doped>*** results will provide theoretical guidance for the stability and electronic structure of non-metallic doped graphene.

关键词： Graphene Non-metallic Electronic structure Optical properties Density functional theory

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Exploring Microstructure and Caloric Effects in Gas-Atomized Ni–Mn–Sn–Co Precursor for Additive Manufacturing

SSRN

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SSRN 2024年

作者： Zhong, Shijiang Qian, Mingfang Gong, Shuhe Shen, Xinxin Li, Yonghua Sun, Liangbo Shen, Ping Zhang, Xuexi Geng, Lin School of Materials Science and Engineering Jilin University No. 5988 Renmin Street Changchun130025 China School of Materials Science and Engineering Harbin Institute of Technology Harbin150001 China Center of Analysis Measurement and Computing Harbin Institute of Technology Harbin150001 China

Recently, additive manufacturing (AM) of intrinsically brittle Ni–Mn–X alloys, in which obtaining high-quality powders is imperative, has received widespread attention. Here, a batch weight of about 34 kg Ni–Mn–Sn–Co powder was prepared using industrial gas atomization equipment. To explore the sinterability of the gas-atomized powder and provide a direct comparison in caloric effects for binder-based AM techniques, we sintered Ni–Mn–Sn–Co alloy powder samples at 1173–1273 K for 2–24 h by using a powder metallurgy process with air cooling. The sintered powder samples had a relative density of about 60.3–80.1%, and 5M martensite and L21–ordered austenite were found to coexist at room temperature. For all sintered samples, martensitic transformation temperature width of about 11–17 K and hysteresis of about 21–23 K were obtained, and strong magneto-structural coupling was observed. The magnetocaloric and elastocaloric effects of the sample sintered at 1273 K for 2 h were examined. A magnetic entropy change of about 23.0 J·kg–1·K–1 and an adiabatic temperature change (ΔTad) of –0.97 K were achieved for magnetic fields of 5.0 and 1.25 T, respectively. Furthermore, a ΔTad of –4.71 K was achieved upon unloading a compressive stress of 350 MPa. These excellent caloric effects in the gas-atomized powder lay the foundation for the AM of Ni–Mn–Sn–Co alloys with complex structures. This study provides a reference for the reliable manufacturing of composition-sensitive Ni–Mn–X Heusler alloys. © 2024, The Authors. All rights reserved.

关键词： Sintering

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A New Approach for measurement of the Low-Temperature Specific Heat Capacity

SSRN

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SSRN 2022年

作者： Jiao, Yang Liu, C.F. Cui, X.P. Huang, L.J. Geng, Lin Center for Analysis Measurement and Computing Harbin Institute of Technology Harbin150001 China School of Materials Science and Engineering Harbin Institute of Technology Harbin150001 China

The manuscript presented the application of simultaneous thermal analyzer (STA449F3) at low-temperature Differential Scanning Calorimetry (DSC) and specific heat capacity tests. Moreover, some problems were found during the specific heat capacity measurement. The STA449F3 instrument can provide accurate characteristic temperature and enthalpy values calculation. However, the specific heat capacity deviation increased gradually when temperature increased above room-temperature. The liquid nitrogen cooling way led to nonlinear temperature during increasing, decreasing and holding temperature process, and larger deviation of low-temperature specific heat capacity. Three methods were adopted to measure the specific heat capacity from below zero to above room-temperature. The error between tested and theoretical values was greatly reduced via creating a non-liquid nitrogen cooling environment. © 2022, The Authors. All rights reserved.

关键词： Room temperature

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