基准平面垂直断面法在爆破漏斗试验中的应用

系统阐述了基准平面垂直断面法在爆破漏斗试验中测量爆破漏斗体积的基本原理,并将隧道激光断面仪应用于金厂河矿1 750 m水平15^#采场底部切割巷道爆破漏斗试验爆破漏斗体积测量中。通过与传统体重法等计算法所得漏斗体积分析比较,结果表明基于隧道激光断面仪与3D Mine软件分析的基准平面垂直断面法实用性强、操作方便、结果直观可靠,达到试验预期目的。     

Adaptive actuator failure compensation design for unknown chaotic multi‐input systems

In this paper, an adaptive control approach is designed for compensating the faults in the actuators of chaotic systems and maintaining the acceptable system stability. We propose a state‐feedback model reference adaptive control scheme for unknown chaotic multi‐input systems. Only the dimensions of the chaotic systems are required to be known. Based on Lyapunov stability theory, new adaptive control laws are synthesized to accommodate actuator failures and system nonlinearities. An illustrative example is studied. The simulation results show the effectiveness of the design method. Copyright © 2014 John Wiley & Sons, Ltd.     

ACCUGRAM: A novel approach based on classification to frequency band selection for rotating machinery fault diagnosis

Frequency band selection (FBS) in rotating machinery fault diagnosis aims to recognize frequency band location including a fault transient out of a full band spectrum, and thus fault diagnosis can suppress noise influence from other frequency components. Impulsiveness and cyclostationarity have been recently recognized as two distinctive signatures of a transient. Thus, many studies have focused on developing quantification metrics of the two signatures and using them as indicators to guide FBS. However, most previous studies almost ignore another aspect of FBS, i.e. health reference, which significantly affect FBS performance. To address this issue, this paper investigates importance of a health reference and recognize it as the third critical aspect in FBS. With help of the health reference, the frequency band where the fault transient exists could be located. A novel approach based on classification is proposed to integrate all three aspects (impulsiveness, cyclostationarity, and health reference) for FBS. Classification accuracy is developed as a novel indicator to select the most sensitive frequency band for rotating machinery fault diagnosis. The proposed method (coined by accugram) has been validated on benchmark and experiment datasets. Comparison results show its effectiveness and robustness over conventional envelope analysis, the kurtogram, and the infogram.     

Structural,electrical, optical and dielectric properties of yttrium substituted cadmium ferrites prepared by Co-Precipitation method

The yttrium substituted cadmium ferrites having composition Cd_1-xY_xFe₂O₄ (X = 0.00, 0.125, 0.250, 0.375, 0.500) were synthesized by the co-precipitation method and sintered at 1100 °C for 6 h. Structural, morphological, electrical, optical and dielectric characteristics were explored by XRD, SEM, EDS, FTIR, I–V two probes, UV–Vis and LCR techniques.XRD results confirmed the cubic structure of spinel ferrites. A decrease in lattice constants of the prepared samples was observed with the substitution of Y ions and was attributed to the difference in ionic radii of Y³⁺ (0.95 Å) and Cd²⁺ (0.97 Å) ions. Cationic distributions, ionic radii of both tetrahedral and octahedral sites, tolerance factor, oxygen positional parameters, bond lengths, interatomic distances, positional parameters and bond length angles were calculated from XRD data. The morphology of the prepared ferrites was studied using SEM and results ratified the XRD results. EDS confirmed the presence of all inserted elements in Cd_1-xY_xFe₂O₄ composition. DC resistivity and drift mobility of soft-ferrites were found to be increased from 1.047 × 10⁸–4.822 × 10¹⁰ Ω-cm and 5.87 × 10⁻¹² – 1.045 × 10⁻¹⁴ cm²V⁻¹s⁻¹, respectively, at 523 K with yttrium content confirming the behavior of semiconductor materials. The optical band gap energy calculated from the UV–Vis pattern of the Cd_1-xY_xFe₂O₄ system was decreased from 3.6011 to 2.8153 eV. DC resistivity and optical band gaps exposed inverse relation. FTIR results revealed lower and upper-frequency absorption bands in the ranges of 419.31–417.01 cm⁻¹ and 540.95–565.70 cm⁻¹, respectively. Dielectric constant and dielectric losses were in decreasing order, while ac conductivity revealed rising behavior with increasing frequency. Results showed the potential of yttrium doped Cd nanoferrites for applications in high-frequency microwave absorbing devices.     

基于投影寻踪的径向基函数网络在参考腾发量预测中的应用

径向基函数网络(RBFN)已广泛应用于参考腾发量预测等领域，但常用的K均值聚类和自组织特征映射等方法在求取径向基函数网络隐层节点中心时存在较大不足。针对这一问题，本文引入投影寻踪方法，在投影降维的基础上实现对大量高维数据的聚类，建立了基于投影寻踪的径向基函数网络模型，并将该模型应用于山西潇河灌区参考腾发量的预测，研究了不同气象因子输入对参考腾发量预测精度的影响。结果表明，基于投影寻踪的径向基函数网络具有较强的适用性，只需使用最高温度、最低温度、日照时数和旬序数作为输入因子，就能以较高的精度预测参考腾发量。     

电流叠加型CMOS基准电压源

介绍了一种CMOS基准电压源,该电路由NMOS管阈值电压的温度系数及NMOS管迁移率温度系数形成温度补偿,产生低温度系数的基准电压。与传统的带隙基准比较而言,不需要三极管;另外,通过结构的改进,变成正负温度系数电流叠加型的基准电压源,可以按需要任意调节输出基准电压的值,而且可以同时提供多个基准电压。电流叠加型基准电压源电路已经在3μmCMOS工艺线上实现,基准电压源输出中心值在2.2 V左右,温度系数为80 ppm/℃。     

Improving narrow bandgap a-SiGe:H alloys grown by hot-wire chemical vapor deposition

We have improved the electronic properties of narrow-bandgap (Tauc gap below 1.5 eV) amorphous-silicon germanium alloys (a-SiGe:H) grown by hot-wire chemical vapor deposition (HWCVD) by lowering the substrate temperature and deposition rate. Prior to this work, we were unable to grow a-SiGe:H alloys with bandgaps below 1.5 eV that had photo-to-dark conductivity ratios comparable with our plasma-enhanced CVD (PECVD) grown materials [B.P. Nelson et al., Mater. Res. Soc. Symp. 507 (1998) 447]. Decreasing the filament diameter from our standard configuration of 0.5 mm to 0.38 or 0.25 mm provides first big improvements in the photoresponse of these alloys. Lowering the substrate temperature from our previous optimal temperatures (T_sub starting at 435 °C) to at 250 °C provides additional photo-to-dark conductivity ratio increasing by two orders of magnitude for growth conditions containing 20–30% GeH₄ in the gas phase (relative to the total GeH₄+SiH₄ flow).     

一种具有高电源抑制比的低功耗CMOS带隙基准电压源

文章设计了一种适用于CMOS工艺的带隙基准电压源电路，该电路采用工作在亚阈值区的电路结构，并采用高增益反馈回路，使其具有低功耗、低电压、高电源电压抑制比和较低温度系数等特点。     

光子晶体与光子晶体光纤的应用

介绍了上世纪80年代末出现的光子晶体的概念和材料特点、光子晶体光纤的性能、国际学术界的研究热点及具有深远影响的应用领域。     

The Person Reference Process in Spontaneous Trait Inferences.

Five studies examined whether spontaneous trait inferences uniquely reference the person who performed a trait-implying behavior. On each study trial in 5 studies, participants saw 2 faces and a behavioral sentence referring to one of them. Later, participants saw face-trait pairs and indicated whether they had seen the trait word in the sentence presented with the face. Participants falsely recognized implied traits more when these traits were paired with actors' faces than with control faces. This effect was replicated for a large set effaces (120), after a week delay between study and recognition test, when equal attention was paid to each face, and when the orientation of the face at recognition was different from the orientation at encoding. (PsycINFO Database Record (c) 2010 APA, all rights reserved)