环锭细纱机牵伸机构应用压力棒的回顾与探讨——兼析压力棒的多种定位方式

针对在现代棉纺环锭细纱机上压力棒的应用现状,进行了简明扼要的历史回顾和由浅入深的分析探讨。由于并条机（乃至粗纱机）前区和细纱机前、后区都在使用压力棒,对直接影响压力棒性能的各种支撑定位方式的特点进行了分析并进行了纺纱对比试验。指出：前、后区压力棒的使用都是通过借助补充、完善摩擦力场、加强对纤维运动的控制来提高成纱质量,其中稳固、精确是下销带压力棒的基本特点,是今后重要的发展方向;强调灵活使用压力棒对赛络纺纱质量的提高主要集中在降低条干CV值、减少IPI纱疵（特别是粗节、棉结）、减少3mm及以上长毛羽,也提升了强伸性能。附加压力棒的应用,虽然对成纱质量的改善不及改造的集聚纺,但较高的性价比使其不失为投资少、质量好、见效快的一种技术措施,应该优先选择使用。     

二维人脸表情仿真技术研究

提出了一种基于单张正面中性表情人脸图像输入的二维人脸表情仿真方法.该方法基于输入的中性表情人脸图像,采用人工神经网络技术对该人脸其它表情下人脸特征点偏移量进行预测,利用预测结果使用基于线性插值的二值表情图像生成方法以及基于人脸图像特征区域变形的灰度表情图像生成方法实现二维人脸表情仿真.仿真结果表明,该方法可满足对人脸表情图像实时性和个性化的仿真需求,为个性化web虚拟人的研究提供技术支持.     

膜转移施胶机的液压故障分析

在膜转移施胶机的调试及生产过程中,发现液压系统经常性的出现一些故障,如：停机时刮刀梁不能长时间保持脱开位置、比例阀控制失效导致压区压力控制失效等,本文提出了解决液压系统故障的办法。     

Is authoritative teaching beneficial for all students? A multi-level model of the effects of teaching style on interest and achievement.

This study examined the effects of the two facets of authoritative teaching—high academic press and caring for students—on student interest and achievement in mathematics for middle and high school students (N = 3,602 in 198 classrooms), and whether those effects are moderated by students' ethnicity (Hispanic, Vietnamese, and Caucasian Non-Hispanic). Tested with hierarchical modeling, a trend suggested that the authoritative teaching style predicted higher levels of interest for Hispanic students; however, the trend for caring was approaching significance, which suggests that future research should be conducted to determine whether authoritative and authoritarian teaching styles truly have different effects on interest for this group. Authoritarian teaching (high press and low caring) was positively related to interest for Vietnamese students. Results for Caucasian students did not differ from Hispanic students, but should be interpreted with caution due to small sample size. For all students, authoritarian teaching was positively associated with achievement gains. Results are discussed in terms of the relationships between teaching style and different academic outcomes among particular student groups, as informed by the parenting style and teaching style literatures. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

A 1 V CMOS programmable accurate charge pump with wide output voltage range

A 1 V, programmable, accurate, high speed, single-ended charge pump is proposed, suitable for low voltage PLLs. It is designed in TSMC 90-nm digital CMOS process and it consists of four switches in a current steering configuration, a unity gain rail to rail buffer for the charge sharing effect elimination, one more rail to rail amplifier for minimizing the DC current mismatch, a programmable current bias circuitry and two drivers based on the standard cell XOR gates specific configuration for achieving good synchronization between all charge pump input pulses at the PLL lock state. Replica biasing technique is applied to all charge pump switches. Current glitches and charge mismatch are suppressed by employing a mechanism with additional switches at the output. It exhibits a maximum DC current mismatch of 1% and charge mismatch of 6% over a wide output voltage range of 0.7 V for the entire range of output currents. The wide range of the output voltage remains relatively constant and independent of the selected charge pump current amplitude. This is attained by applying appropriate variation of the W/L ratios of the bias cascode current sources via the employment of additional programmable switches such that their saturation voltages remain relatively constant, something which in turn enables the output currents range to be as wide as it is required.     

LTE系统时频同步算法及其DSP实现

介绍了LTE—FDD系统主同步序列的产生,给出了一种基于主同步信道的时频同步算法,包括符号定时同步算法和频偏估计算法。定时同步算法引入了多径能量窗,并且根据LTE系统同步信道的特点,对多个同步信道上的相关值进行非相干合并,有效地提高了同步性能。对所给出的算法进行仿真,并采用DSP实现同步算法。仿真和实验结果表明,所给出的算法具有良好的性能,能够满足LTE系统对同步性能的要求。     

Joint estimation of carrier frequency offset, dc offset and I/Q imbalance for OFDM systems

Orthogonal frequency division multiplexing (OFDM) systems with direct-conversion receiver (DCR) are vulnerable to carrier frequency offset (CFO), dc offset (DCO) and in-phase/quadrature (I/Q) imbalance. In this paper, we propose blind estimator for joint estimation of CFO, DCO and I/Q imbalance in OFDM systems with DCR. Simulation results show that performance of proposed estimator approaches Cramér-Rao lower bound (CRLB) asymptotically, which demonstrates its effectiveness.     

钢管高强混凝土核心柱轴心受压复合刚度研究

本文在对12根柱试件在弹性阶段的轴压复合刚度的试验研究的基础上,参考大量文献、规程,分别计算核心钢管混凝土和外围钢筋混凝土复合刚度,进行叠加得到钢管高强混凝土核心柱复合刚度,所得结果与试验结果较为～致。     

铝合金蛇形轧制轧板曲率解析模型研究

根据蛇形轧制的受力特点将变形区划分为5个不同的区域,分别计算了各个区域的压力分布及角位移,在此基础上运用平面应变主应力法建立了7150铝合金蛇形轧制轧板曲率的解析模型.通过蛇形轧制实验对解析模型的精确性进行了验证.使用该解析模型对蛇形轧制过程中由线性应变差引起的轧板曲率、剪切应变差引起的轧板曲率以及总的轧板曲率进行了研究.结果表明,随着错位距离的增加由剪切应变差引起的轧板曲率增加而由线性应变差引起的轧板曲率减小,它们的共同作用导致总的轧板曲率先减小后增加.随着异速比的增加,由剪切应变差引起的轧板曲率增加,由线性应变差引起的轧板曲率保持不变,它们的共同效果使总的轧板曲率增加.增大轧板初始厚度或减小压下量都会减小轧板曲率.     

利用SSP模块改善热轧带钢边部线状缺陷

边部线状缺陷是发生在热轧带钢上的常见缺陷,当前研究结果发现该类缺陷产生于水平轧制时带坯棱角部金属翻转至表面的过程.据此理论,对板坯定宽侧压机(SSP)模块进行形状上的设计应用,通过SSP模块改变带坯侧面形状,缩短缺陷距带钢边部距离,实现了减少切边量、提高成材率的目的.