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Complete Your Mobility： Linking Trajectories Across Heterogeneous Mobility Data Sources

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Journal of Computer Science & Technology 2018年第4期33卷 792-806页

作者： Guo-Wei Wang Jin-dou zhang Jing Li School of Computer Science and Technology University of Science and Technology of China Hefei 230026 China

Nowadays, human activities and movements are recorded by a variety of tools, forming different trajectory sets which are usually isolated from one another. Thus, it is very important to link different trajectories of one person in different sets to provide massive information for facilitating trajectory mining tasks. Most prior work took advantages of only one dimensional information to link trajectories and can link trajectories in a one-to-many manner （providing several candidate trajectories to link to one specific trajectory）. In this paper, we propose a novel approach called one-to-one constraint trajectory linking with multi-dimensional information （OCTL） that links the corresponding trajectories of one person in different sets in a one-to-one manner. We extract multidimensional features from different trajectory datasets for corresponding relationships prediction, including spatial, temporal and spatio-temporal information, which jointly describe the relationships between trajectories. Using these features, we calculate the corresponding probabilities between trajectories in different datasets. Then, we formulate the link inference problem as a bipartite graph matching problem and employ effective methods to link one trajectory to another. Moreover, the advantages of our approach are empirically verified on two real-world trajectory sets with convincing results.

关键词： trajectory linking trajectory data mining trajectory similarity mobility pattern mining

Ion sulphuration-an effective surface engineering technique for reducing friction and wear of rubbing-pairs

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中国有色金属学会会刊：英文版 2004年第Z1期14卷 13-18页

作者： LIU Jia-jun WANG Hai-dou zhang Ning zhang Da-ming Department of Mechanical Engineering Tsinghua University Beijing 100084 China National Key Laboratory for Remanufacturing Academy of Armored Force Engineering Beijing 100072 China Chinergy Co. Ltd. Beijing 100084 China Department of Mechanical Engineering Tsinghua University Beijing 100084 China

The low temperature ion sulphuration-an effective surface engineering technique for reducing friction and wear of rubbing-pairs was introduced. It involves the principle of ion sulphuration process, microstructure of FeS film on 1045 steel, tribological properties of FeS film on steels, microstructions and tribological properties of MoS2 and nano-FeS/MoS2 multi-layered films, as well as their applications.

关键词： solid lubrication low temperature ion sulphuration friction and wear surface engineering

Cascaded plasmonic nanorod antenna for large broadband local electric field enhancement

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Chinese Physics B 2019年第10期28卷 535-540页

作者： dou zhang Zhong-Jian Yang Jun He Hunan Key Laboratory of Super Microstructure and Ultrafast Process School of Physics and ElectronicsCentral South University

We propose a cascaded plasmonic nanorod antenna for large broadband electric near-field enhancement. The structure has one big gold nanorod on each side of a small two-wire antenna which consists of two small gold nanorods. For each small nanorod, the enhanced and broadened optical response can be obtained due to the efficient energy transfer from its adjacent big nanorod through strong plasmonic near-field coupling. Thus, the electric field intensity of the cascaded antenna is significantly larger and broader than that of the individual small two-wire antenna. The resonant position, field intensity enhancement, and spectral width of the cascaded antenna are highly tunable by varying the geometry of the system. The quantum efficiency of the cascaded antenna is also greatly enhanced compared with that of the small antenna. Our results are important for the applications in field-enhanced spectroscopy.

关键词： surface plasmon optical antenna electric field enhancement broadband cascaded

Improvement in piezoelectric performance of the lead-free BiFeO_(3)-BaTiO_(3) ceramics by synergistic approach

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Journal of Materials Science & Technology 2023年第29期160卷 55-65页

作者： Muhammad Habib Lin Tang Guoliang Xue Xuefan Zhou dou zhang State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China

High-piezoelectric properties in lead-free materials have been the pursuit for both industry and scientific *** this work,the synergistic approaches of phase/domain engineering and novel poling method are adopted for the improvement of piezoelectric *** strategically designed lead-free donor-doped BiFeO_(3)-x BaTiO_(3) ceramics at the crystal structure morphotropic phase boundary(MPB)between the rhombohedral and tetragonal phases exhibited a high Curie temperature(T C≥450°C).Furthermore,si-multaneously enhanced static piezoelectric constant(d_(33))of 436±5 pC/N and thermally stable dynamic piezoelectric constant(d_(33)^(∗))of 550±10 pm/V were *** high piezoelectric performance is col-lectively attributed to the crystal structure MPB,thermal quenching effect,local structure heterogeneity induced by donor doping,mesoscale nanodomains,and novel poling method inside a magnetic *** temperature-insensitive and high piezoelectric performance of the current work is superior to the other lead-free *** synergistic approach for the improvement of piezoelectricity provides a path for the development of lead-free ceramics for high-temperature commercial applications.

关键词： Lead-free piezoceramics BiFeO_(3)-BaTiO_(3) Quenching Temperature-insensitive AC-poling

Optimized strain performance in <001>-textured Bi_(0.5)Na_(0.5)TiO_(3)-based ceramics with ergodic relaxor state and core-shell microstructure

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Journal of Advanced Ceramics 2022年第10期11卷 1542-1558页

作者： Xuefan ZHOU Huiping YANG Guoliang XUE Hang LUO dou zhang Powder Metallurgy Research Institute Central South UniversityChangsha 410083China

Herein,a high strain of ~0.3% with a small hysteresis of 43% is achieved at a low electric field of 4 kV/mm in the highly -textured 0.97(0.76Bi_(0.5)Na_(0.5)TiO_(3)-0.24SrTiO_(3))-0.03NaNbO_(3)(BNT-ST-0.03NN)ceramics with an ergodic relaxor(ER)state,leading to a large normalized strain(d_(33)^(*))of 720 pm/*** introduction of NN templates into BNT-ST induces the grain orientation growth and enhances the *** highly -textured BNT-ST-0.03NN ceramics display a pure ergodic relaxor state with coexisted ferroelectric R3c and antiferroelectric P4bm polar nanoregions(PNRs)on ***,due to the incomplete interdiffusion between the NN template and BNT-ST matrix,the textured ceramics present a core-shell structure with the antiferroelectric NN core,and thus the BNT-based matrix owns more R3c PNRs relative to the homogeneous nontextured *** high crystallographic texture and more R3c PNRs both facilitate the relaxor-to-ferroelectric transition,leading to the low-field-driven high strain,while the ergodic relaxor state ensures a small ***,the d_(33)^(*)value remains high up to 518 pm/V at 100℃ with an ultra-low hysteresis of 6%.

关键词： Bi_(0.5)Na_(0.5)TiO_(3)(BNT)-based ceramics ergodic relaxor(ER)state crystallographic texture core-shell structure optimized strain performance

Enhanced piezoelectricity in Na and Ce co-doped CaBi_(4)Ti_(4)O_(15) ceramics for high-temperature applications

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Journal of Advanced Ceramics 2023年第7期12卷 1331-1344页

作者： Zimeng Hu Vladimir Koval Hangfeng zhang Kan Chen Yajun Yue dou zhang Haixue Yan School of Engineering and Materials Science Queen Mary University of LondonLondon E14NSUK Institute of Materials Research Slovak Academy of SciencesKosice 04001Slovakia Spallation Neutron Source Science Center Dongguan 523803China Institute of High Energy Physics Chinese Academy of Sciences(CAS)Beijing 100049China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China

The sodium(Na)and Ce co-doped calcium bismuth titanate(CBT;CaBi_(4)Ti_(4)O_(15))Aurivillius ceramics in a Ca_(1-x)(Na_(0.5)Ce_(0.5)),Bi_(4)Ti_(4)O_(15)(CNCBT;doping content(x)=0,0.03,0.05,0.08 and 0.12)system were synthesized by the conventional solid-state sintering *** compositions show a single-phase orthorhombic(space group:A2jam)structure at room *** shift of the Curie point(T_(c))towards lower temperatures(T)on doping results from the increased tolerance factor(t).The substitution-enhanced ferroelectric performance with large maximum polarization(P_(m))and facilitated domain switching is evidenced by the developed electrical polarization-electric field(P-E)and electrical current-electric field(I-E)hysteresis *** piezoelectric coefficient(d_(33)=20.5±0.1 pC/N)of the x=0.12 sample is about four times larger than that of pure *** improved piezoelectric properties can be attributed to the high remanent polarization(P_(r))and relatively high dielectric permittivity(ε′).In addition,multi-sized(micron and sub-micron)domain structures were observed in the CNCBT ceramics by the piezoresponse force microscope(PFM).The multiple-sized ferroelectric domain structure with smaller domains is beneficial to the easy domain switching,enhanced ferroelectric performance,and improved piezoelectric properties of the CNCBT *** designed Aurivillius-phase ferroelectric ceramics with the T_(c) around 765℃and high piezoelectric coefficient(d_(33))are suitable for high-temperature piezoelectric applications.

关键词： Aurivillius-phase ceramics high Curie point domain switching,piezoelectric properties

Multiple Effects Tailoring the Self-organization Behaviors of Triphenylene Side-chain Liquid Crystalline Polymers via Changing the Spacer Length

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Chinese Journal of Polymer Science 2018年第8期36卷 960-969页

作者： Xiang-Hui Han Xi-Wen Yang Sheng Chen Hang Luo dou zhang Hai-Liang zhang Key Laboratory of Polymeric Materials and Application Technology of Hunan Province Key Laboratory of Advanced Functional Polymer Materials of Colleges and Universities of Hunan ProvinceCollege of ChemistryXiangtan University State Key Laboratory of Powder Metallurgy Central South University

Long-alkyl tail triphenylene （TP） side-chain liquid crystalline polymers （SCLCPs） with different spacer length （P-m-TP, m = 2, 3, 4, 6, 8, which is the number of carbon atom in the flexible alkyl spacers） have been successfully synthesized via free radical polymerization. The differential scanning calorimetry （DSC）, polarized light microscopy （POM）, ultraviolet-visible spectroscopy （UV- Vis）, wide-angle X-ray diffraction （WAXD） and small-angle X-ray scattering （SAXS） measurements were performed to investigate the influence of multiple effects on the self-organization behaviors of P-m-TP, including steric effect, decoupling effect and π-π stacking effect. The experimental results revealed that P-m-TP （m = 2, 3, 4） formed the columnar phase which was developed by the TP moieties and the main chain as a whole, suggesting that the side-chains had strong steric effect even though the number of spacer length （m） exceeded 4. In addition, the clearing points （Tis） of the polymers were above 300 ℃. When m = 6 and 8, the polymers displayed hexagonal columnar phase and exhibited the low Tis （91 and 80 ℃ respectively）, originating from the self-assembly of triphenylene due to the decoupling effect and π-π stacking effect. This work offers a viable and inspiring pathway to control the phase transition temperature and phase structure ofTP SCLCPs via simply tailoring the spacer length and increasing the alkyl tail length of TP.

关键词： Polymer synthesis Side-chain liquid crystalline polymers Phase structure Steric effect

Effect of advanced paternal age on reproductive outcomes in IVF cycles of non-male-factor infertility: a retrospective cohort study

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Asian Journal of Andrology 2023年第2期25卷 245-251页

作者： Xin-Mei Lu Yu-Bing Liu dou-dou zhang Xiang Cao Tian-Cheng zhang Miao Liu Hui-Juan Shi Xi Dong Su-Ying Liu Reproductive Medicine Center Zhongshan HospitalFudan UniversityNo.180 Fenglin RoadShanghai 200032China NHC Key Lab of Reproduction Regulation Shanghai Institute for Biomedical and Pharmaceutical TechnologiesPharmacy SchoolFudan UniversityNo.2140 Xietu RoadShanghai 200032China Center for Reproductive Medicine Tenth People’s Hospital of Tongji University301 Middle Yanchang RoadShanghai 200072China

Advanced paternal age has been overlooked,and its effect on fertility remains *** studies have focused mainly on intracytoplasmic sperm injection(ICSI)cycles in men with ***,few studies have reported on men with semen parameters within reference ***,we conducted a retrospective cohort study analyzing the reproductive outcomes of couples with non-male-factor infertility undergoing in vitro fertilization(IVF)*** total,381 cycles included were subgrouped according to paternal age(0.05).The pregnancy rate was not significantly different in the 35–39-year-old group(42.0%;P>0.05),but was significantly lower in the≥40-year-old group(26.1%;P0.05),but showed a declining *** miscarriage rate significantly increased in the 35–39-year-old group(44.8%)compared with that in the<35-year-old group(21.0%;P<0.05).No abnormality in newborn birth weight was *** results indicated that paternal age over 40 years is a key risk factor that influences the assisted reproductive technology success rate even with good semen parameters,although it has no impact on embryo development.

关键词： embryo development implantation in vitro fertilization paternal age pregnancy sperm

Preparation of CuCr alloys by thermit-reduction electromagnetic stirring

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Journal of University of Science and Technology Beijing 2007年第6期14卷 538-542页

作者： Zhihe dou Tingan zhang Haien Yu Liping Niu Xiaoli Jiang Huan Yang School of Materials and Metallurgy Northeastern University Shenyang 110004 China

The influences of the additive CaF2, different molds, mold pre-heating temperature, electromagnetic stirring, and alloying elements on CuCr have been investigated respectively during the preparation of CuCr alloys by thermit-reduction electromagnetic stirring. The results indicate that the reasonable reactant mass ratio of CuO： Cr2O3：Al is 100：140：160; CaF2 can reduce the solidification point of slags to improve the metal separating efficiency from slags; the crystal particles become thinner because of the high cooling velocity in the metal mold; while casting in the graphite mold, the casting properties of CuCr improve with the increase of pre-heating temperature; the compact alloys are prepared at 500℃; electromagnetic stirring can prevent the growth of dendrite crystal into refine crystal particles, as well as homogenize Cu and Cr to improve the CuCr properties; the optimal stirring time is 7 min; when the alloying elements Ni and Co are added to the reactants, elements Cu and Cr can distribute evenly but the crystal particles become thick.

关键词： contact material CuCr alloy thermit reduction electromagnetic stirring additive