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Recommendation Method for Contrastive Enhancement of Neighborhood Information

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Computers, materials & Continua 2024年第1期78卷 453-472页

作者： Hairong Wang beijing Zhou Lisi Zhang He Ma School of Computer Science and Engineering North Minzu UniversityNingxia750021China

Knowledge graph can assist in improving recommendation performance and is widely applied in various person-alized recommendation ***,existing knowledge-aware recommendation methods face challenges such as weak user-item interaction supervisory signals and noise in the knowledge *** tackle these issues,this paper proposes a neighbor information contrast-enhanced recommendation method by adding subtle noise to construct contrast views and employing contrastive learning to strengthen supervisory signals and reduce knowledge ***,first,this paper adopts heterogeneous propagation and knowledge-aware attention networks to obtain multi-order neighbor embedding of users and items,mining the high-order neighbor informa-tion of users and ***,in the neighbor information,this paper introduces weak noise following a uniform distribution to construct neighbor contrast views,effectively reducing the time overhead of view *** paper then performs contrastive learning between neighbor views to promote the uniformity of view information,adjusting the neighbor structure,and achieving the goal of reducing the knowledge noise in the knowledge ***,this paper introduces multi-task learning to mitigate the problem of weak supervisory *** validate the effectiveness of our method,experiments are conducted on theMovieLens-1M,MovieLens-20M,Book-Crossing,and Last-FM *** results showthat compared to the best baselines,our method shows significant improvements in AUC and F1.

关键词： Contrastive learning knowledge graph recommendation method

Nd-doped barium titanate ceramics with various Ti/Ba ratios prepared by sol-gel method

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Science china Chemistry 2005年第Z1期48卷 60-64页

作者： SHI Qizhen,CUI Bin,WANG Hui,TIAN Jing,CHANG Zhuguo & HOU Yudong Department of Chemistry,Northwest university,Shaanxi key laboratory of Physico-lnorganic Chemistry,Xi’an 710069,china key laboratory of advanced functional materials of china Education Ministry,beijing university of technology,beijing 100022,china Department of Chemistry Northwest University Shaanxi Key Laboratory of Physico-lnorganic Chemistry Xi’an China key laboratory of advanced functional materials of china Education Ministry Beijing University of Technology Beijing China

The Nd-doped BaTiO3 nanocrystalline powders and ceramics with different Ti/Ba ratios were prepared by sol-gel method. Phases and microstructures of the Nd-doped BaTiO3based powders and ceramics were characterized by XRD, SEM and TEM methods. The results revealed that the powders synthesized by sol-gel method were nanometer scale (30-60 nm)and were mainly composed of cubic BaTiO3 with a small amount of BaCO3. After sintering at high temperature, both cubic BaTiO3 and BaCO3 were transformed into tetrahedron BaTiO3 *** dielectric properties of the ceramics were also determined and the influence of Ti/Ba ratio on the dielectric properties was discussed. The Tc did not change with the variation of Ti/Ba ratio,while the εmax increased firstly and then decreased. The excess TiO2 is benefit for the modification of ceramics' microstructure and dielectric properties.

关键词： sol-gel method, dielectric properties, nanometer materials, Nd-doped barium titanate, Ti/Ba mole ratio.

Thermodynamic Functions and Phase Transformation of Metal Nanocrystals

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Journal of materials Science & technology 2005年第5期21卷 705-709页

作者： Jinping GAO, Xiaoyan SONG , Jiuxing ZHANG, keyong YANG and Xuemei LIUCollege of materials Science and Engineering, the key laboratory of advanced functional materials of the Education Ministry,beijing university of technology, beijing 100022, china key laboratory of advanced functional materials College of Materials Science and Engineering Beijing University of Technology Beijing 100022 China

A model to calculate the thermodynamic functions of the pure metal nanocrystals has been developed, with the consideration of the effects of both the interfaces and the crystal in the nano-grain interior. As an example, the enthalpy, entropy and Gibbs free energy, as functions of the excess free volume at interfaces, temperature and grain size, are calculated for the Co nanocrystals. Furthermore, the characteristics of β-Co→α-Co phase transformation are studied, and the transformation temperatures at different levels of grain size, as well as the critical grain sizes at different temperatures, are predicted. The calculation results show that, the nano-grained β-Co （fcc） is thermodynamically stable at temperatures much lower than that for the conventional coarse-grained materials, and may also stably exist at room temperature when the grain size is reduced to be small enough. The present model is verified by comparisons between the experimental findings and the theoretical predictions.

关键词： Thermodynamic function Nanocrystal Phase transformation

A Creep Equation Based on Thermal Activation

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International Journal of Minerals,Metallurgy and materials 1998年第1期12卷 44-46页

作者： Jiyue Sun Guoliang Chen (State key laboratory for advanced Metals and materials, university of Science and technology beijing, beijing 100083, china) State key laboratory for advanced Metals and materials University of Science and Technology Beijing Beijing 100083 China

The creep equation proposed in so called θ projection concept is developed in the concept of thermal activation of creep. The measured creep curves of A286 alloy are fitted by the equation. The activation energy in theequation is evaluated, and creep rupture lives are predicted. The results are confirmed by creep tests of up to 13years.

关键词： creep creep curve equation creep rupture life A286 superalloy

Advances in Thermionic Cathode of Tungsten and Molybdenum

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Rare Metals 2001年第3期20卷 137-141页

作者： Jinshu Wang,Meiling Zhou, Tieyong Zuo, Juan Liu, Jiuxing Zhang, Zuoren Nie The key laboratory of advanced functional materials, Ministry of Education, School of materials Scence and Engineering, beijing Polytechnic university, beijing 100022, china 北京工业大学教育部新型功能材料重点实验室北京 100022.

Several kinds of tungsten thermonic cathodes have been introduced. As a promising alternative for thoriated tungsten, rare earth doped molybdenum cathode has been studied. Compared with the traditional thoriated tungsten, La-Mo cathode has higher emission current density at lower temperature, but it has poor emission stability. In order to improve the emission stability, systematical study on the emission mechanism of La-Mo cathode has been carried out. The life of La-Mo cathode has been improved and has achieved 1400 It, which exceeds the minimum life for practical uses (1000 h). As another alternative for thoriated tungsten cathode, Y-Mo cathode has shown better performance. The thermionic emission capability of Y-Mo cathode is between that of La-Mo cathode and Th-W cathode.

关键词： tungsten molybdenum thermonic cathode emission

Distribution of Nb atom in the TiAl+Nb system

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Rare Metals 2001年第1期20卷 5-12页

作者： Xiaodong Ni, Xidong Hui, Guoliang Chen (Applied Science School, university of Science and technology beijing, beijing 100083, china State key laboratory for advanced Metals and materials, university of Science and technology beijing, china) Appl. Sci. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

Based on MEAM (the modified embedded atom method) potential and an average atom model similar to B-W (Bragg-Williams) method, the distribution of Nb atoms in TiAl+Nb compounds with various composition was calculated. The calculation results showed that Nb atoms prefer to occupy the Ti sublattice of L10 structure for all compounds in question. With increasing atomic fraction of Nb and Al, Nb atoms exhibited a trend of ordered distribution on the Ti sublattice and result in a new L10 derivative superlattice structure.

关键词： Computer simulation Intermetallics Superlattices Ternary systems

Structure Evolution of Bulk Metallic Glass Zr_(52.5)Ni_(14.6)Al_10Cu_(17.9)Ti_5 during Annealing

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Journal of materials Science & technology 2000年第4期16卷 357-361页

作者： Guo HE, Zan BIAN and Guoliang CHEN (State key laboratory of advanced Metals and materials, university of Science and technology beijing,beijing 100083, china) State key laboratory of advanced Metals and materials University of Science and Technology Beijing Beijing 100083 China

Bulk metallic glass Zr_52.5Ni_14.6Al_10Cu_17.9Ti_5 was prepared by melt injection casting method. Its glass transition and crystallization temperatures were determined by differential scanning calorimetry (DSC) to be 631 K and 710 K respectively. By analysis of X-ray diffractometry (XRD) and transmission electron microscopy (TEM ), the predominant crystallized phase of Zr_2Ni0.67O0.33 distributed on glass state matrix was detected after annealing at 673 K for 600 s. The transformation to Zr_2Ni_0.67O_0.33 and a small amount of ZrAl and Zr_2Cu took place after annealing for 600 s at temperature from 703 K to 723 K. With increasing annealing temperature from 753 K to 823 K, the amounts of ZrAl and Zr_2Cu increased, but the size of the crystals did not significantly change. The transformation to Zr_2Ni_0.67O_0.33 is interface-controlled, but is diffusion-controlled to Zr_2Cu and ZrAl. With increasing annealing temperature up to 200 K above T_x, the nanometer grains became very fine because of the increase of nucleation rate for Zr_2Cu and ZrAl.

关键词： Structure Evolution of Bulk Metallic Glass Zr Ti5 during Annealing Al10Cu Ni Cu

MEAM Potential with Angular Dependence for TiAl

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Rare Metals 2001年第1期20卷 13-17页

作者： Xiaodong Ni, Xitao Wang, Guoliang Chen (Physics Department, university of Science and technology beijing, beijing 100083, china State key laboratory for advanced Metals and materials, university of Science and technology beijing, beijing 100083, china) 北京科技大学新金属材料国家重点实验室北京 100083 北京科技大学北京 100083

The modified embedded atom method (MEAM) is an empirical extension of the embedded atom method (EAM) that includes angular forces. By fitted to the lattice constants, the cohesive energy, the APE (anti-phase boundary) energy, and the vacancy formation energy of TiAl, an accurate MEAM potential is obtained for the TiAl system with L10 structure. The calculation results of the properties of TiAl are in good agreement with experiments and the results of first principle (F.P.) calculations.

关键词： embedded atom method TiAl alloy angular dependence potential intermetallics

Micro-alloying of yttrium in Zr-based bulk metallic glasses

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Progress in Natural Science:materials International 2011年第1期21卷 46-52页

作者： Wei-jie PENG,Yong ZHANG State key laboratory for advanced Metals and materials, university of Science and technology beijing,beijing 100083,china State key laboratory for advanced Metals and materials University of Science and Technology Beijing Beijing 100083 China

The effect of yttrium addition on the glass-forming ability(GFA) and mechanical properties of the Zr-based (Zr0.525Al0.1Ti0.05Cu0.179Ni0.146)100-xYxand(Zr0.55Al0.15Ni0.1Cu0.2)100-xYx(x=0,0.2,0.4 0.6,1,2) alloys was ***-alloying of 0.6%yttrium enhances the room temperature ductility as well as the GFA of the Zr-based *** mechanism of enhancing the GFA and room temperature ductility was *** is indicated that proper yttrium addition stabilizes the undercooled liquid by means of forming lots of ordered clusters,thus improving the GFA and the room temperature ductility.

关键词： micro-alloying glass-forming ability Zr-based alloys yttrium