Some new members of MAX family including light-elements: Nanolayered Hf2XY (X= Al,Si, P and Y=B,C, N)

The structural, electronic, mechanical and dynamical properties of new members of MAX family (Hf₂XY, X=Al, Si, P and Y= B, C, N compounds) with Cr₂AlC-type structure have been investigated by first-principles density functional plane-wave pseudopotential calculations within generalized gradient approximation. From calculated cohesive energies, all compounds are energetically stable. And, from calculated elastic constants and phonon dispersion curves, it is shown that all compounds are mechanically stable, while the boron including ones are dynamically unstable except for Hf₂PB. At the same time, related mechanical properties such as bulk and shear moduli are calculated. For further mechanical characterization, hardnesses of the compounds are determined theoretically. It is observed from electronic structure calculations including band structure and partial density of states, all stable compounds are metallic. Additionally, bonding nature of the compounds are analyzed by using 3D and 2D electron density maps, Mulliken atomic charges and bond overlap populations.     

3DMAX模型在VRML中的数据简化

在保持3DS MAX原始模型特征的情况下,利用顶点删除法对数据模型中的三角形进行合并处理。对合并后的多边形重新进行三角划分,从而实现对满足一定条件的冗余三角形的简化处理,最大限度地减少原始模型的三角形和顶点的数目,以达到提高显示速度的目的。最后给出的实例说明了该方法的有效性。     

采用MAX813L芯片对复位电路可靠性提高的讨论

文中对五种单片机复位电路进行了分析并作比较．结合几种不同复位电路在实际产品上的应用结果,表明采用MAX813L专用复位芯片可以大大提高产品的稳定性和可靠性．     

一种调幅红外无线耳机的设计

采用MAX1726与MAX9722器件,通过幅度调制方式,实现一款红外无线耳机.该红外无线耳机具有供电方式多样、方向性好、音量可调节等功能.给出了详细设计原理与硬件实现.     

MXenes的制备、结构调控及电化学储能应用

MXenes因其独特的二维层状结构、较高的比表面积、优异的导电性、良好的表面亲水性和化学稳定性,受到国内外研究者的广泛关注。近年来,研究者普遍采用含氟刻蚀剂(HF与LiF-HCl等)选择性刻蚀MAX相中的A位元素,制备带有丰富表面基团的多层MXenes材料。由于含氟刻蚀剂的污染问题,当前采用更为绿色环保的无氟刻蚀剂(NaOH与ZnCl₂等)刻蚀MAX相的研究报道越来越多。MXenes的性能与其结构密切相关,不同制备方法对MXenes的层间距和表面基团的影响很大,进而也影响其性能。基于此,本文总结对比了文献中MXenes的制备方法,概述了MXenes层间距和表面基团的调控方法,同时介绍了MXenes在电化学储能方面的应用,最后对今后MXenes研究所面临的挑战和发展方向进行了展望。     

MAX232在串口通信中的作用分析与测试

讨论了MAX232集成芯片在PC机串口通信中的作用，分析了测试MAX232芯片性能的方法。     

一种特殊信号发生器的设计

本设计以函数信号发生器集成芯片MAX038为核心，充分利用该芯片的功能来实现特殊输出波形的要求。频率调节利用芯片自身功能来实现，幅值调节通过运放来实现。     

带均衡电路的锂电池充电器的设计与实现

MAX1757是MAXIM公司生产的一种锂离子电池充电控制器,它具有可编程性,外围电路简单等特点,可实现充电控制各种参数的设定.设计了基于MAX1757的三节锂电池串联充电控制管理的硬件电路,给出了充电参数的设定方法并分析了四个充电状态.设计了均衡充电电路,并给出了实验结果.     

First‐order Raman scattering of the MAX phases: Ti2AlN,Ti2AlC0.5N0.5, Ti2AlC, (Ti0.5V0.5)2AlC,V2AlC,Ti3AlC2, and Ti3GeC2

Here, we report, for the first time, on the Raman spectra of Ti₂AlN, Ti₂AlC_0.5N_0.5, (Ti_0.5V_0.5)₂AlC, Ti₃AlC₂, and Ti₃GeC₂ and compare the results with those of Ti₂AlC and V₂AlC reported previously. The first‐order mode peaks of the end members are narrower than those of their respective solid‐solution compounds. The Ti₃AlC₂ and Ti₃GeC₂ phases show, in addition to atomic displacements of the ‘M’ and ‘A’ atomic planes, modes that correspond with vibrations of the ‘X’ sublattice relative to itself. We also predict the Raman modes using density functional theory. The agreement between theory and experiment was found to be satisfactory. Copyright © 2011 John Wiley & Sons, Ltd.     

用双光路方法精确测量光栅衍射效率

光栅衍射效率是光栅的重要参数．设计了用双光路并利用计算机作数据采集和处理来测量光栅衍射效率的方法．实验中使用的微电流放大器的分辨能力为10pA．自行研制了数据采集卡以及编写了基于计算机的增强型并行接口（enhanced parallel port，EPP）协议的软件，使得测量精确度达到2．1％．能够较好地满足光栅衍射效率的测量．