烧混-1胶带机驱动装置故障分析及技术改造     

王中元  赵曙光 《昆明大学学报》2007,18(4):20-22,26

昆钢烧结厂三烧车间烧混-1胶带机减速机随着生产顺行，烧结机上料量增加以及产量的大幅度提高。该驱动装置的承载能力已不能满足生产需求，减速机因承受交变载荷出现高速轴、中间轴扭断，齿轮点蚀严重、减速机箱体发热等缺陷而造成系统频繁停机，严重影响了生产的正常运行，同时增加了备件消耗。鉴于此，对烧混-1胶带机减速机进行了提高承载能力及通风冷却的改造。  相似文献   

解析法确定从动件为等速运动规律的凸轮基圆半径     

程葆伦  罗永前 《重庆职业技术学院学报》2005,14(4):54-55

本文尝试采用解析法，按许用压力角确定直动从动件盘形凸轮机构的基圆半径和偏心距。该方法只适用于从动件为等速运动规律的凸轮机构。  相似文献   

The Contribution of Naming Speed to the Simple View of Reading     

Timothy C. Johnston  John R. Kirby 《Reading and writing》2006,19(4):339-361

The purpose of this study was to investigate whether naming speed makes a contribution to the prediction of reading comprehension, after taking into account the product of word decoding and listening comprehension (i.e., the Simple View of Reading; [Gough, P.B. & Tunmer, W.E. (1986). Remedial and Special Education 7, 6–10]), and phonological awareness. In grade 3, word decoding was measured with the Woodcock [(1998). Woodcock Reading Mastery Tests – Revised. Circle Pines, MN: American Guidance Services]. Word Identification and Word Attack subtests, listening comprehension with the Woodcock (1991) [Woodcock Language Proficiency Battery – Revised. Chicago: Riverside Publishing Company] test of Listening Comprehension, naming speed with a picture naming task, and 4 measures assessed phonological awareness. Reading comprehension was assessed in grades 3, 4, and 5 with the Woodcock (1998) Passage Comprehension subtest and in grade 5 with the Gates–MacGinitie reading test. The Simple View was evaluated twice: first, with a pseudoword measure for decoding (Grapheme–Phoneme-conversion product) and, second, with a word identification measure for decoding (word recognition product). Hierarchical regression and commonality analyses indicated that the decoding and listening comprehension products accounted for considerable variance in reading comprehension. Naming speed had a small but significant effect after accounting for the Grapheme–Phoneme-conversion product (2–3%), but little effect after accounting for the word-recognition product (0–2%). Subgroup analyses indicated that naming speed had its primary effect for less able readers. Commonality analyses supported the interpretation that naming speed contributes after the Grapheme–Phoneme-conversion product but not after the word recognition product because naming speed has already had its effect upon word recognition. These results indicate that it is important how the Simple View decoding term is defined, and that the Simple View may be incomplete, especially for less able readers.  相似文献   

Novel Sensorless Vector Control System of Induction Machine Based on Flux Observer in Field Weakening     

邹积勇  许镇琳孙凯 《天津大学学报(英文版)》2006,12(1):1-5

A speed-sensorless vector control system for induction machines （IMs）is presented, According to the vector control theory of IMs, the rotor flux is estimated based on a flux observer,and the speed is estimated through the method of q-axis rotor flux converging on zero with proportional integral regulator, A 0.75 kW,50 Hz,two-pole induction machine was used in the simulation and experimental verification, The simulation model was constructed in Matlab. A series of tests were performed in the field weakening region, for both no-load and loaded operation. The estimated speed tracks the actual speed well in the based speed region and field weakening region （ 1 per unit value to 4 per unit value）. The small estimation error of residual speed is due to the existence of slip.  相似文献   

急行跳远助跑过程中速度利用率的探讨     

李宗香  王进 《通化师范学院学报》2004,25(4):80-82

通过对高等院校体育学院(系)田径队跳跃组男子跳远运动员的助跑速度、平跑速度、速度利用率的测试，结合自身实践，并大量的查闼相关资料进行综合分析，试探讨跳远助跑速度利用率和成绩的关系，以便指导运动实践．  相似文献   

从翻译过程的“合”到翻译成果的“和”——“和合”翻译学始末     

李霞 《唐山师范学院学报》2012,34(1):15-18

和合说起源于中国古代"天人合一"的哲学思想,是一种整体思维。在此基础上提出的和合翻译说避免了翻译局部研究引起的纷争,把翻译过程中的各个要素有机、动态、开放地融合在一起,使得矛盾不断得到化解,新事物不断得到化生。分析译者在选择原作、意义再生、翻译策略以及译语读者期待四方面的"和合"意识,进一步论证了和合翻译思想对翻译实践的指导作用。  相似文献   

电流截止负反馈自动调速控制电路设计     

金轶锋 《渭南师范学院学报》2012,(10):44-47

在电压负反馈和电流正反调速控制系统中增设了自动限制电枢电流的电路,并能实现在正常运行时限制电枢电流电路与负反馈调速控制系统自动分离,当电流增大到一定程度时又能自动投入.既克服了由于电流负反馈使系统的静特性变软的不足,又能满足一般调速系统的要求.  相似文献   

速度对奥运会470级帆船船体阻力和压力分布的影响     

张志勇  马勇  蔺世杰 《西安体育学院学报》2021,(1):124-128

目的得到航速对于470级帆船船体的阻力大小影响的系列规律,增加运动员对帆船船体水动力性能认识,更加高效操纵帆船。方法利用计算流体动力学方法,湍流模式采用RNG k-ε湍流模型,运用SIMPLE算法进行求解,空间离散格式采用二阶迎风格式,边界条件均设置为速度入口、压力出口,数值模拟了速度为2 m/s、4 m/s、6 m/s、8 m/s、10 m/s等5种工况下帆船船体水动力性能,分析不同航速条件下船体的阻力和压力分布。结果船体受到的阻力随航速的增大而增大,在阻力增大趋势线中低航速条件下阻力变化斜率较小、高航速条件下阻力斜率较大。根据趋势线确定阻力与航速的乘幂公式,可以预测不同航速条件下船体在不考虑兴波条件下的船体所受到的阻力大小。研究中不同航速对船体压力分布的规律基本一致,造成的影响主要体现在船体不同部位受力的值上,不同航速对船体船首局部压力造成的影响差异很大。船体考虑兴波时压力分布规律影响差异较大,在不考虑兴波时航速对船体压力分布规律影响较小。结论航速对于船体的阻力大小影响较大,船体阻力随航速的增大而增大;船体阻力随航速变化可以用乘幂公式拟合;船体的兴波对船体阻力分布规律影响不可忽略。  相似文献   

第49届世界体操锦标赛单杠成套动作编排特征研究     

刘敦晓 《辽宁体育科技》2021,(2)

运用文献资料法、录像观察法和数理统计法,对参加第49届世界体操锦标赛的前8名单杠决赛运动员成套动作的编排特征进行研究。结果显示:(1)成套动作选择以Ⅱ、Ⅲ组动作为主,动作难度集中趋向C、D、E三个组别,A、B组动作使用数量锐减,并向着F、G、H组更高难度动作不断努力;(2)第Ⅰ组动作中大回环转体类动作成为首选,第Ⅱ组动作形成特卡切夫类、马尔凯洛夫类、空翻越杠类"三足鼎立"局面,第Ⅲ组动作中穿衍生动作为主体,正、反掏类动作使用稳定,第Ⅳ组下法仍未打破直体后空翻两周转体类动作的垄断局面;(3)"特卡切夫类+特卡切夫类"仍为编排主流,"马凯洛夫类+马凯洛夫类"成为编排亮点,"空翻越杠类+空翻越杠类"成为编排"杀手锏",连接串由"二连飞"向"三、四连飞"跨越发展,使动作连接技术更具惊险性、欣赏性、创新性。  相似文献   

KPSF-35传动用自动控制系统设计中电流自适应与平波电抗器的组合应用     

董学彤 《天津职业院校联合学报》2013,15(5):23-28

传动用自控系统设计,传统设计采用平波电抗器维持电流连续确保控制对象的工作,但铜耗多、体积大。电流自适应也可解决问题但效果欠佳,＂电流自适应＋平波电抗器＂解决方案,充分利用各自特点,即降低铜耗又最大限度满足系统的要求,提高了性能价格比。  相似文献