虚拟实验室在实践教学环节中的实现途径

虚拟现实作为一种新兴技术在以培养操作型、技能型人才为目标的高等职业教育领域内有着巨大的应用前景.阐述虚拟现实技术的概念、分类,并针对职业技术教育的特点提出适合现阶段发展水平的虚拟现实技术改革教学思路,尤其从实践环节方面来促进创新教育、强化技能培训.     

基于3DS MAX的会泽铅锌矿区遥感影像的三维可视化

随着地球科学及计算机图形图像学的不断发展,三维地质建模及可视化已引起地学界的高度重视.自然地质现象极为复杂,二维地质数据在认识三维状态下的地质体有很大的局限性.利用计算机图形学及可视化技术,将二维抽象的地学信息以三维可视化的图形方式直观形象地显示出来,创建逼真的三维空间地质体模型具有重要意义.本文阐述了以会泽铅锌矿区遥感影像为基础,利用3DS MAX中各种建模、材质贴图等一系列工具对会泽铅锌矿区地表信息的可视化模拟.     

PWM升压控制器MAX668/MAX669及其应用

MAX668／MAX669是美国MAXIM公司生产的固定频率的PWM控制器。本文详细介绍了其主要特性、管脚排列，并给出了自举和非自举操作时的典型应用电路。     

固态继电器在固体蓝光激光器温度控制系统中的应用

当808 nm的红外激光通过YAG晶体时,激光泵浦Nd:YAG产生的热效应使晶体发热量很大,要求对YAG晶体制冷的TEC的最大功率为144 W.当946 nm的红外激光通过LBO晶体时,要求对LBO晶体制冷的TEC的最大功率为30 W,现有的一些专门的TEC控制芯片均无法达到以上所述电流及功率.可以用弱信号控制强电流并且其灵敏度高,切换速度快(可达1 ms),无机械运动零部件,寿命长,可靠性高,开关过程中没有抖动.在如上所述制冷量如此大的情况下采用固态继电器驱动TEC工作,只要选择合适的电源,并配合相应的PID软件控制就可以控制Nd:YAG晶体温度波动在±0.375℃.LBO晶体温度波动在±0.250℃.在除湿环境中,激光器可以稳定输出1.6 W的蓝光.     

高速8位ADC MAX156在数控车床切削力测量中的应用

MAX156是MAXIM公司生产的具有跟踪/保持功能的高速、多通道8位A/D模数转换器(ADC),结合其在数控车床切削力测量中的应用,着重分析了MAX156的结构、功能特性、工作原理及其应用。     

具2+δ阶矩的一类时变MAX(q)序列的样本均值的极限分布

本文继续作者在文献[1]中的工作,证明具2+δ(0<δ<1)阶原点矩的时变 MAX(q)序列{x_n)的样本均值 N~(1/2)(_N-E_N)渐近正态分布 N(0,ν_2-ν_2-(2q+1)μ~2),其中μ_1=Ex_1,ν_2=E(x_1+x_2+…+x_(q+1))~2,ν_2=E(x_1+x_2+…+x_q)~2,从而,减弱了文献[1]中要求{x_n}具有限三阶原点的限制条件.但其论证方法与文献[1]不相同.     

Structural,elastic, electronic and thermal properties of M2SbP (M = Ti,Zr and Hf)

The structural, elastic, electronic and thermal properties of M₂SbP (M = Ti, Zr and Hf) were studied by means of a pseudo-potential plane-wave method based on the density functional theory within both the local density approximation and the generalised gradient approximation. The optimised zero-pressure geometrical parameters, i.e. the two unit cell lengths (a, c) and the internal coordinate (z), were in good agreement with available experimental and theoretical data. The effect of high pressure, up to 20 GPa, on the lattice constants shows that the contractions along the a-axis were higher than along c-axis. The anisotropic independent elastic constants were calculated using the static finite strain technique. Numerical estimations of the bulk modulus, shear modulus, Young's modulus, Poisson's ratio, average sound velocity and Debye temperature for ideal polycrystalline M₂SbP aggregates were performed in the framework of the Voigt–Reuss–Hill approximation. The calculated band structures show that all studied materials are electrical conductors. Analysis of the atomic site projected densities showed that the bonding is of covalent–ionic nature with the presence of metallic character. The density of states at the Fermi level is dictated by the transition metal d–d bands; the Sb element has little effect. Thermal effects on some macroscopic properties of M₂SbP were predicted using the quasi-harmonic Debye model, in which the lattice vibrations are taken into account. The variations of the volume expansion coefficient, heat capacity and Debye temperature with pressure and temperature in the ranges 0–50 GPa and 0–2000 K were obtained successfully.     

Synthesis and characterization of arc deposited magnetic (Cr,Mn)2AlC MAX phase films

(Cr_1–xMn_x)₂AlC MAX phase thin films were synthesized by cathodic arc deposition. Scanning transmission electron microscopy including local energy dispersive X‐ray spectroscopy analysis of the as‐deposited films reveals a Mn incorporation of as much as 10 at% in the structure, corresponding to x = 0.2. Magnetic properties were characterized with vibrating sample magnetometry, revealing a magnetic response up to at least room temperature. We thus verify previous theoretical predictions of an antiferromagnetic or ferromagnetic ground state for Cr₂AlC upon alloying with Mn. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

低功耗FSK超外差式接收电路设计

所设计的308 MHz/315 MHz/418 MHz/433.92 MHz低功耗FSK超外差式接收电路,采用MAX7042高集成度、低功耗,CMOS型超外差式射频(RF)接收芯片,灵敏度为-110~-109 dBm,接收频移键控(FSK)数据速率可达66 kbps(NRZ)(33kbps曼彻斯特编码);文中介绍了MAX7042的主要技术性能、内部结构、工作原理和应用电路.     

3DS MAX中TREE FACTORY(树工厂)插件的运用

TREEFACTORY(树工厂 )插件是 3DSMAX很重要的组成部分。利用它可以产生各种各样的树 ,这些树可应用到游戏、室内外虚拟环境的布置中。苹果树是其中一种很具有代表性的树 ,通过对它的产生过程的研究 ,可以完整地了解树工厂插件的组成及其运用