In order to explore the effect of vacancy defects on the structural,electronic,magnetic and optical properties of CoS_(2) and FeS_(2),first-principles calculation method was used to investigate the alloys.The calculat...In order to explore the effect of vacancy defects on the structural,electronic,magnetic and optical properties of CoS_(2) and FeS_(2),first-principles calculation method was used to investigate the alloys.The calculated results of materials without vacancy are consistent with those reported in the literatures,while the results of materials with vacancy defect were different from those of literatures due to the difference vacancy concentration.The Co vacancy defect hardly changes the half-metallic characteristic of CoS_(2).The Fe vacancy defect changes FeS_(2) from semiconductor to half-metal,and the bottom of the spin-down conduction band changes from the p orbital state of S to the d(t_(2g))orbital state of Fe,while the top of the valence band remains the d orbital d(eg)state of Fe.The half-metallic Co vacancy defects of CoS_(2) and Fe vacancy defects of FeS_(2) are expected to be used in spintronic devices.S vacancy defects make both CoS_(2) and FeS_(2) metallic.Both the Co and S vacancy defects lead to the decrease of the magnetic moment of CoS_(2),while both the Fe and S vacancy defects lead to the obvious magnetic property of FeS_(2).Vacancy defects enhance the absorption coefficient of infrared band and long band of visible light obviously,and produce obvious red shift phenomenon,which is expected to be used in photoelectric devices.展开更多
针对簧片哨空化噪声的问题,首先通过ANSYS模拟簧片哨的振动,研究簧片哨的振动频率;然后通过水听器测量方法采集簧片哨的空化噪声数据,并利用ORIGIN软件分析噪声谱,最后分析模拟结果与噪声谱的关系.结果表明,簧片哨模拟振动频率与实际测...针对簧片哨空化噪声的问题,首先通过ANSYS模拟簧片哨的振动,研究簧片哨的振动频率;然后通过水听器测量方法采集簧片哨的空化噪声数据,并利用ORIGIN软件分析噪声谱,最后分析模拟结果与噪声谱的关系.结果表明,簧片哨模拟振动频率与实际测得的频率基本相符;在不同水压条件下,簧片哨的噪声谱基本一致,测得的基频为0.8 k Hz,泛频为1.6 k Hz、2.4 k Hz、3.2 k Hz、4.0 k Hz、4.8 k Hz等;簧片哨的噪声谱具有明显的线状谱特点,但噪声谱的频率为可听声频率范围而不是超声频率范围.簧片哨的线状空化噪声谱特点有利于加强空化效果.展开更多
基金Funded by the Scientific and Technologial Innovation Programs of Higher Education Institutions in Shanxi (No. 2020L0628)the Taiyuan Institute of Technology Scientific Research Initial Funding (No. 2022KJ072)+2 种基金the Program for the (Reserved) Discipline Leaders of Taiyuan Institute of Technologythe Fundamental Research Funds for the Central Universities (Nos. 2017TS004, 2017TS006, and GK201704005)Supported by HZWTECH for providing computational facilities
文摘In order to explore the effect of vacancy defects on the structural,electronic,magnetic and optical properties of CoS_(2) and FeS_(2),first-principles calculation method was used to investigate the alloys.The calculated results of materials without vacancy are consistent with those reported in the literatures,while the results of materials with vacancy defect were different from those of literatures due to the difference vacancy concentration.The Co vacancy defect hardly changes the half-metallic characteristic of CoS_(2).The Fe vacancy defect changes FeS_(2) from semiconductor to half-metal,and the bottom of the spin-down conduction band changes from the p orbital state of S to the d(t_(2g))orbital state of Fe,while the top of the valence band remains the d orbital d(eg)state of Fe.The half-metallic Co vacancy defects of CoS_(2) and Fe vacancy defects of FeS_(2) are expected to be used in spintronic devices.S vacancy defects make both CoS_(2) and FeS_(2) metallic.Both the Co and S vacancy defects lead to the decrease of the magnetic moment of CoS_(2),while both the Fe and S vacancy defects lead to the obvious magnetic property of FeS_(2).Vacancy defects enhance the absorption coefficient of infrared band and long band of visible light obviously,and produce obvious red shift phenomenon,which is expected to be used in photoelectric devices.
文摘针对簧片哨空化噪声的问题,首先通过ANSYS模拟簧片哨的振动,研究簧片哨的振动频率;然后通过水听器测量方法采集簧片哨的空化噪声数据,并利用ORIGIN软件分析噪声谱,最后分析模拟结果与噪声谱的关系.结果表明,簧片哨模拟振动频率与实际测得的频率基本相符;在不同水压条件下,簧片哨的噪声谱基本一致,测得的基频为0.8 k Hz,泛频为1.6 k Hz、2.4 k Hz、3.2 k Hz、4.0 k Hz、4.8 k Hz等;簧片哨的噪声谱具有明显的线状谱特点,但噪声谱的频率为可听声频率范围而不是超声频率范围.簧片哨的线状空化噪声谱特点有利于加强空化效果.
