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.     

12位AD转换器MAX1246/MAX1247的原理及应用

ＭＡＸ１２４６／ＭＡＸ１２４７是ＭＡＸＩＭ于１９９７年最新出品的１２位串行输出Ａ／Ｄ转换芯片．具有工作能耗低、采样、转换速度快、精度高、接口逻辑简单以及灵活的可编程控制模式等优点．详细分析和说明了该芯片的工作原理、特点及注意事项     

Optimization of Oxygen Parameters for Determination of Carbon and Nitrogen in Biochar Materials

Recently, there has been increased focus on biochar materials due to their ability to sequester carbon for long-term in soil. In the production of biochar or charcoal, plant biomass is heated in a low or no oxygen environment. This process results in a product with unique characteristics. But there is limited research on the standardization of methods for determining total carbon (C) and nitrogen (N) in the biochar materials whose properties vary by feedstock type and pyrolytic conditions. The objective of this study was to determine the oxygen dosing time (OT) and dose (OD) for total organic carbon (TC) and nitrogen (TN) analysis in biochar materials by dry combustion method (using Vario Max CNS analyzer). Central composite rotatable design was used to determine the effect of five levels of oxygen dosing time (OT) and dosing level (OD) on measurement of total carbon and total nitrogen in four types of plant originated biochars. OT and OD level interaction had significant impact on the measurement of TC and TN in all types of biochar materials. Optimum levels of OT and OD were determined as 103 to 110 sec and 180 to 232 ml/min, respectively.     

网络RTK测量MAX与VRS技术优势分析

本文基于笔者多年从事工程测量的相关工作经验,以网络RTK在工程测量应用中的关键技术为研究对象,从实践经验处罚,结合笔者参考的大量文献,对其中涉及的三项关键技术的原理,优势和不足给出了分析评价,全文是笔者长期工作实践基础上的理论升华,相信对从事相关工作的同行有着重要的参考价值和借鉴意义。     

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.     

基于FPGA的欧洲应答器编码实现

应答器作为车地间信息传输的方式之一,在列车运行控制系统中有广泛的应用,欧洲列车控制系统(ETCS)就利用欧洲应答器(EUROBALISE)来实现车-地间的通信.本文在EU-ROBALISE编码原理的基础上,设计了一种利用现场可编程逻辑门阵列(FPGA)来实现EU-ROBALISE实时编码的方法,在MAX PLUS Ⅱ平台上应用VHDL硬件描述语言进行了仿真分析,最后的验证结果表明设计正确,达到了预期的目的.     

Structural, electronic and elastic properties of Ti2TlC, Zr2TlC and Hf2TlC

Using First-principle calculations, we have studied the structural, electronic and elastic properties of M₂TlC, with M = Ti, Zr and Hf. Geometrical optimization of the unit cell is in good agreement with the available experimental data. The effect of high pressures, up to 20 GPa, on the lattice constants shows that the contractions are higher along the c-axis than along the a axis. We have observed a quadratic dependence of the lattice parameters versus the applied pressure. The band structures show that all three materials are electrical conductors. The analysis of the site and momentum projected densities shows that bonding is due to M d-C p and M d-Tl p hybridizations. The M d-C p bonds are lower in energy and stiffer than M d-Tl p bonds. The elastic constants are calculated using the static finite strain technique. We derived the bulk and shear moduli, Young’s modulus and Poisson’s ratio for ideal polycrystalline M₂TlC aggregates. We estimated the Debye temperature of M₂TlC from the average sound velocity. This is the first quantitative theoretical prediction of the elastic properties of Ti₂TlC, Zr₂TlC, and Hf₂TlC compounds that requires experimental confirmation.      

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