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22.
The magnetization reversal behaviour for SmCo6.8Zr0.2 and SmCo6.8Zr0.2a-(Fe,Co) nanocrystalline magnets at low temperature 下载免费PDF全文
This paper reports that the SmCo6.8Zr0.2 nanocrystalline permanent magnets and SmCo6.8Zr0.2/a-(Fe,Co) nanocomposite permanent magnets are successfully produced by mechanical alloying and subsequently annealing at 700℃ for 10 minutes. The x-ray diffraction results show that the phase structure of SmCo6.8Zr0.2 nanocrystalline permanent magnets is composed of SmCo7 phase and SmCo6.8Zr0.2/a-(Fe,Co) nanocomposite permanent magnets is composed of SmCo7 and a-(Fe,Co) phases. The mechanism of magnetization reversal is mainly controlled by inhomogeneous domain wall pinning in SmCo6.8Zr0.2 and SmCo6.8Zr0.2/a-(Fe,Co) magnets. The inter-grain exchange interaction at low temperature is investigated, which shows that the inter-grain exchange interaction of SmCo6.8Zr0.2/a-(Fe,Co) magnets increases greatly by the decrease of the measured temperature. According to Amirr-H/Hcj, Amrev-H/Hcj and Xirr-H/Hcj curves at room temperature and 100 K, the changes of irreversible and reversible magnetization behaviours of SmCo6.8Zr0.2 and SmCo6.8Zr0.2/a-(Fe,Co) magnets with the decreasing temperature are analysed in detail. The magnetic viscosity and the activation volume of SmCo6.8Zr0.2 and SmCo6.8Zr0.2/a-(Fe,Co) magnets at different temperatures are also studied. 相似文献
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为了研究偏振光在椭球细粒子中多次散射的传输特性,建立了以黑碳气溶胶粒子为对象的仿真与实验验证系统。采用T矩阵和蒙特卡罗相结合的方法,对偏振光经随机取向椭球细粒子多次散射后的偏振传输特性进行仿真研究,建立半实物模拟测试平台对仿真方法进行验证,采用延长灵芝孢子燃烧时间的方式制备椭球细粒子,分别由马尔文粒度仪和光功率计测试椭球细粒子的尺寸分布和光学厚度,建立实验与仿真间的联系,验证了仿真结果的正确性。结果表明:随着黑碳椭球细粒子浓度的增加,水平、垂直、+45°线偏光和右旋圆偏光的偏振度都随之下降,且3种线偏振光的保偏性基本一致;随着浓度的增大,圆偏振光的保偏性逐渐优于线偏振光,且两者保偏性差距越来越大,在光学厚度为3.12时达到最大值,当光学厚度大于3.12时,圆偏光和线偏光的偏振度差值趋于稳定。经计算,仿真与实验结果符合度优于70.84%。本研究结果可扩展偏振探测的适用范围,为非球形颗粒物环境下偏振探测研究提供理论支撑。 相似文献
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洛阳北魏大市遗址出土玻璃珠成分分析 总被引:3,自引:0,他引:3
采用原子吸收光谱法(AAS)洛阳北魏大市遗址出土的玻璃珠成分和用X射线衍射(XRD)技术研究了其晶体结构,实验结果显示了玻璃珠主要成分Na2O、K2O、CaO、MgO、Fe2O3、CuO、PbO、MnO、Al2O3、ZnO、NiO、SiO2和给出了其XRD图,并以这些实验数据为依据讨论了玻璃珠的来源及形态。 相似文献
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胆红素,胆绿素与金属离子的作用机制初探 总被引:5,自引:0,他引:5
用电化学方法和光谱方法对胆红素、胆绿素与金属离子在碱性水溶液中的作用机制进行了研究。发现它们与金属离子的作用情况依金属离子种类和反应条件不同而异。在有氧情况下,碱土、稀土等金属离子不与它们发生作用,Hg^2+、Ag^+、Tl^+、Hg^2+2等则可与它们发生直接氧化还原或催化氧化反应;而在除氧的条件下,胆红素、胆绿素则可与Fe^3+、Cu^2+、Zn^2+、Cd^2+等形成配合物,而无催化氧化反… 相似文献
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Modeling of high permittivity insulator structure with interface charge by charge compensation 下载免费PDF全文
An analytical model of the power metal–oxide–semiconductor field-effect transistor(MOSFET)with high permittivity insulator structure(HKMOS)with interface charge is established based on superposition and developed for optimization by charge compensation.In light of charge compensation,the disturbance aroused by interface charge is efficiently compromised by introducing extra charge for maximizing breakdown voltage(BV)and minimizing specific ON-resistance(Ron,sp).From this optimization method,it is very efficient to obtain the design parameters to overcome the difficulty in implementing the Ron,sp–BV trade-off for quick design.The analytical results prove that in the HKMOS with positive or negative interface charge at a given length of drift region,the extraction of the parameters is qualitatively and quantitatively optimized for trading off BV and Ron,sp with JFET effect taken into account. 相似文献