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| 1 | Electrical properties of yttrium calcium oxyborate crystal annealed at high temperature and low oxygen partial pressure显示文摘The yttrium calcium oxyborate crystal(YCa_(4)O(BO_(3))_(3),YCOB)has been actively studied for hightemperature piezoelectric sensing applications.In this work,the stability of electric properties of YCOB crystal annealed in critical conditions(high-temperatures of 900-1100℃ with a low oxygen partial pressure of 4×10^(-6) atm for 24 h)was investigated and the recovery mechanism for the electrical resisitivity,dielectric permittivity and dielectric loss were studied,taking advantage of the X-ray photoelectron spectra and the first principle calculations.The electrical resistivity of the annealed YCOB crystal was slightly decreased when compared to the pristine counterpart,being(2-5)×10^(7) Ω·cm at 850C.The dielectric permittivity and dielectric loss were found to increase after annealing,showing recoverable behaviours after thermal treatment above 650℃ in air.The calculated vacancy formation energy indicates that the oxygen vacancy is the dominant defects in YCOB.The formation of oxygen vacancy weakens the chemical bonding strength between B(Ca or Y)and O atoms,introduces extra donor levels in the band gap,which excites the electrons to conduction band more easily thus enhances the electrical conductivity and dielectric loss.The recovered electrical properties are believed to be associated with the reduced vacancy defects at elevated temperatures in air. | Shiwei Tian Lili Li Feifei Chen Chao Jiang Fapeng Yu Yanlu Li Xiulan Duan Zhengping Wang Shujun Zhang Xian Zhao | 2019 | Journal of Materiomics2019，5，3： | 2 |
| 2 | Runoff pre- dictions in ungauged catchments in southeast Tibetan Plateau显示文摘 | LI Fapeng ZHANG Yongqiang XU Zongxue | 2014 | Journal of Hydrology2014，511，： | 1 |
| 3 | Research on Flexible Job Shop Scheduling Optimization Based on Segmented AGV显示文摘As a typical transportation tool in the intelligent manufacturing system,Automatic Guided Vehicle(AGV)plays an indispensable role in the automatic production process of the workshop.Therefore,integrating AGV resources into production scheduling has become a research hotspot.For the scheduling problem of the flexible job shop adopting segmented AGV,a dual-resource scheduling optimization mathematical model of machine tools and AGVs is established by minimizing the maximum completion time as the objective function,and an improved genetic algorithmis designed to solve the problem in this study.The algorithmdesigns a two-layer codingmethod based on process coding and machine tool coding and embeds the task allocation of AGV into the decoding process to realize the real dual resource integrated scheduling.When initializing the population,three strategies are designed to ensure the diversity of the population.In order to improve the local search ability and the quality of the solution of the genetic algorithm,three neighborhood structures are designed for variable neighborhood search.The superiority of the improved genetic algorithmand the influence of the location and number of transfer stations on scheduling results are verified in two cases. | Qinhui Liu Nengjian Wang Jiang Li Tongtong Ma Fapeng Li Zhijie Gao | 2023 | Computer Modeling in Engineering & Sciences2023，，3： | 0 |
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