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基于最优品质因子信号共振稀疏分解的滚动轴承故障诊断

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振动工程学报 2015年第6期28卷 998-1005页

作者：李星于德介张顶成湖南大学汽车车身先进设计制造国家重点实验室湖南长沙410082

滚动轴承常常在复杂工况下工作,当滚动轴承出现局部故障时,其振动信号中除了与故障信息相关的周期性瞬态冲击成分外,还包含轴转频等谐波成分和背景噪声。因此,在滚动轴承故障早期,对滚动轴承振动信号直接进行包络解调分析往往效果不佳... 详细信息

滚动轴承常常在复杂工况下工作,当滚动轴承出现局部故障时,其振动信号中除了与故障信息相关的周期性瞬态冲击成分外,还包含轴转频等谐波成分和背景噪声。因此,在滚动轴承故障早期,对滚动轴承振动信号直接进行包络解调分析往往效果不佳。针对上述问题,提出了基于最优品质因子信号共振稀疏分解的滚动轴承故障诊断方法。该方法首先以信号共振稀疏分解低共振分量的峭度最大为目标,利用遗传算法对信号共振稀疏分解方法的品质因子进行优化,得到最优品质因子;然后利用最优品质因子对轴承振动信号进行信号共振稀疏分解,得到高共振分量和低共振分量;最后对低共振分量进行希尔伯特解调分析,提取轴承故障特征频率,进而诊断滚动轴承故障。仿真信号和试验信号的分析结果表明,该方法能有效提取轴承故障振动信号中的冲击成分,诊断轴承故障。

关键词：故障诊断滚动轴承共振稀疏分解品质因子遗传算法

基于模糊Bow-tie模型的城镇燃气管道泄漏定量风险评价

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天然气工业 2013年第7期33卷 134-139页

作者：於孝春贾朋美张兴南京工业大学机械与动力工程学院中国石油管道科技研究中心

燃气管道事故一旦发生后果大多比较严重。为全面分析燃气管道风险的前因后果,确定重点维护和监控的管段区域,引入了Bow-tie模型,将管道泄漏的故障树与事件树统一到一起对燃气管道进行定量风险评价。采用模糊集相关理论与专家评价相结合... 详细信息

燃气管道事故一旦发生后果大多比较严重。为全面分析燃气管道风险的前因后果,确定重点维护和监控的管段区域,引入了Bow-tie模型,将管道泄漏的故障树与事件树统一到一起对燃气管道进行定量风险评价。采用模糊集相关理论与专家评价相结合的方法得出管道泄漏的模糊可能值;然后基于模糊层次分析法确定管道泄漏后果因素的权重系数;再通过矩阵乘法求得泄漏后果值。以某段燃气管线为案例,全面识别出各风险因素,量化得到管道各泄漏后果事件的风险值。实际应用结果表明:①该方法可快速合理地评判出管道系统的相对风险大小;②三角模糊数与层次分析法的应用减少了传统评价中主观及模糊因素产生的评价偏差,使得评价结果更接近客观实际;③依据评价结果制订有针对性的预防维护措施,能够实现有限维护资源的合理配置,保障燃气管道的安全可靠运行。

关键词：燃气管道模糊Bow—tie模型故障树事件树定量风险评价模糊层次分析法三角模糊数泄漏后果

Dicer in Schwann cells is essential for the maintenance of axon integrity in adult mice

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Dicer in Schwann cells is essential for the maintenance of a...

中国神经科学学会第十二届全国学术会议

作者： Tao Li Jingjing Wang Hongkai Wang Nanxin Huang xing Gao Feng Mei lan Xiao Department of Histology and Embryology Chongqing Key Laboratory of NeurobiologyThird Military Medical University

Objective Dicer is an enzyme that responsible for generating functional noncoding micro-RNAs(miRNAs), which has been shown to importantly participate in regulation of myelination in CNS or PNS. Recent evidence indicated that myelinating glia cells, oligodendrocytes(OLs) in CNS and Schwann cells(SCs) in PNS, also provide nutrition for the energy consumption of axons. To investigate the functional consequence of Dicer deletion in myelinating glial cells post-myelination in adulthood, we induced Dicer deletion in 8-week old mice(PLP-cre ERT2;Dicer fl/fl) by tamoxifen. Methods Conditional knock out is achieved by tamoxifen induced cre recombination in specific target cells. The motor abnormalities are evaluated by tail lift test, grid test, beam walking and open field. The pathology of sciatic nerve is identified by immunofluorescence staining(IFC) and electron microscope(EM) observation. Micro RNA array is used for primary candidate targeting. Results We found progressive motor dysfunctions in these mice, which started as hind limb ataxia month after recombination and deteriorated into hind limb ataxia and paralysis, caused by massive axon degeneration/atrophy in the sciatic nerves. To understand whether this phenotype is due to Dicer deletion in OLs, we induced Dicer deletion in OLs at P9 in the NG2-cre ERT2;Dicer fl/fl mice. Dicer deletion in OLs did not cause similar symptoms at the same age, suggesting this phenotype was caused by the Dicer deletion in SCs rather than OLs. Concomitantly, the PLP-cre ERT2;Dicer fl/fl mice showed premature hair greying, suggesting Dicer is also responsible for maintaining melanoblasts. Bio-informatic analysis of miRNAs array from the PLP-cre ERT2;Dicer fl/fl sciatic nerves indicated that miRNAs that in charge of lipid metabolism were greatly changed. Conclusion All together, our results reveal that Dicer in Schwann cells is essential for the maintenance of axon integrity of PNS in adult mice.

关键词： Dicer Schwann cell motor dysfunction sciatic nerve axon degeneration

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一种带落角约束的精确导引方法(英文)

宇航学报 2012年第5期33卷 570-576页

作者：覃天陈万春邢晓岚北京航空航天大学宇航学院北京100191 空军装备研究院总体所北京100085

为了解决落角控制问题,本文提出了一种新的导引规律。它在零化脱靶量的同时可以达到任何期望的落角。该导引律不需要弹目距离信息和估计飞行剩余时间,并且在理想条件下,对非机动目标可实现完美拦截(零脱靶量和零落角误差)。此外,该导引... 详细信息

为了解决落角控制问题,本文提出了一种新的导引规律。它在零化脱靶量的同时可以达到任何期望的落角。该导引律不需要弹目距离信息和估计飞行剩余时间,并且在理想条件下,对非机动目标可实现完美拦截(零脱靶量和零落角误差)。此外,该导引律可使加速度指令在拦截目标前收敛到零,这有利于加大弹头的侵彻深度。通过与参考文献中两种导引律的仿真对比,表明了本文提出的导引律在落角控制方面的优越性能。

关键词：导引落角约束完美拦截

基于文献计量学的土壤盐渍化研究动态定量综述

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清华大学学报（自然科学版） 2024年第2期64卷 303-317页

作者：王忠静于蘇越许兴宁夏大学土木与水利工程学院银川750021 清华大学土木水利学院北京100084 宁夏大学农学院银川750021

土壤盐渍化研究纷繁复杂,传统的文献综述方法因主观性强较难全面准确把握学科动态。该文引入文献计量学,提出了一种学科方向研究动态的定量综述方法;基于WoS(Web of Science)和中国知网(China National Knowledge Infrastructure,CNKI)... 详细信息

土壤盐渍化研究纷繁复杂,传统的文献综述方法因主观性强较难全面准确把握学科动态。该文引入文献计量学,提出了一种学科方向研究动态的定量综述方法;基于WoS(Web of Science)和中国知网(China National Knowledge Infrastructure,CNKI)数据库近30 a土壤盐渍化及盐碱地治理与利用的相关文献,定量综述了该学科领域研究动态和发展趋势。结果表明,国内外土壤盐渍化研究呈上升趋势,但总体上处于研究的初始阶段,仍有很大发展空间;中国、美国、印度、澳大利亚等国在土壤盐渍化及盐碱地改良与利用研究上贡献突出,中国学者发表论文数量最多,是土壤盐渍化研究的主力;核心作者间合作密切,但跨背景、跨机构、跨国家的合作仍然较少;研究热点已从上世纪90年代的灌溉排水与盐碱地改良,转移到当前的土壤植物盐分互作机制及耐盐植物培育、土壤水盐调控机制与优化控制技术、盐渍土改良剂研发技术及其规模化应用、盐碱地遥感监测与盐渍化影响评价等方向,代表着土壤盐渍化及盐碱地治理与利用研究从排水改良为主向综合利用延伸的发展趋势。

关键词：土壤盐渍化盐碱地治理与利用文献计量定量综述

Epidemiological and clinical characteristics of fifty-six cases of COVID-19 in Liaoning Province, China

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World Journal of Clinical Cases 2020年第21期8卷 5188-5202页

作者： Jing-Bo Wang Hai-Tao Wang Lei-Shi Wang Lu-Ping Li Jiao Xv Chun Xv xing-Hai Li yun-Hai Wu Hong-Yan Liu Bai-Jun Li Hong yu Xia Tian Zhi-yu Zhang Yan Wang Rui Zhao Jin-Yang Liu Wei Wang Ye Gu Department of Infectious Disease The Sixth People’s Hospital of ShenyangShenyang 110006Liaoning ProvinceChina Department of General Surgery The Second Affiliated Hospital of Shenyang Medical CollegeShenyang 110002Liaoning ProvinceChina Department of Clinical Laboratory The Sixth People’s Hospital of ShenyangShenyang 110006Liaoning ProvinceChina Department of Intensive Critical Medicine The Sixth People’s Hospital of ShenyangShenyang 110006Liaoning ProvinceChina Department of Infectious Diseases Clinic The Sixth People’s Hospital of ShenyangShenyang 110006Liaoning ProvinceChina

BACKGROUND Pneumonia of uncertain cause has been reported in Wuhan,China since the beginning of early December *** early January 2020,a novel strain ofβ-coronavirus was identified by the Chinese Center for Disease Control and Prevention from the pharyngeal swab specimens of patients,which was recently named severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).There is evidence of human-to-human transmission and familial cluster outbreak of SARSCoV-2 *** World Health Organization(WHO)recently declared the SARS-CoV-2 epidemic a global health *** of February 17,2020,71329 laboratory-confirmed cases(in 25 countries,including the United States and Germany)have been reported *** than its rapid transmission,the epidemiological and clinical characteristics of coronavirus disease 2019(COVID-19)remain *** December 2019,coronavirus disease(named COVID-19 by the WHO)associated with the SARS-CoV-2 emerged in Wuhan,China and spread quickly across the *** To analyze the epidemiological and clinical characteristics of confirmed cases of this disease in Liaoning province,a Chinese region about 1800 km north of *** The clinical data of 56 laboratory-confirmed COVID-19 cases due to 2019-nCoV infection were *** cases originated from eight cities in Liaoning *** The median age of the patients was 45 years,and 57.1%of them were *** patient had been in direct contact with wild *** them,23 patients(41.1%)had resided in or traveled to Wuhan,27 cases(48.2%)had been in contact with confirmed COVID-19 patients,5 cases(8.9%)had been in contact with confirmed patients with a contact history to COVID-19 patients,and 1 case(1.8%)had no apparent history of ***(75.0%)and cough(60.7%)were the most common *** typical manifestations in lung computed tomography(CT)included ground-glass opacity and patchy shadows,with 67.8%of them being *** the patients in the cohort,78.6%

关键词： SARS-CoV-2 COVID-19 Epidemiological characteristics Clinical characteristics Hypoxemia Acute respiratory distress syndrome

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一水硬铝石型铝土矿选择性絮凝分选工艺研究

中国矿业大学学报 2006年第6期35卷 742-746页

作者：王毓华黄传兵兰叶中南大学资源加工与生物工程学院湖南长沙410083

采用沉降试验法系统地考查了阴离子聚丙烯酰胺(AP7),阳离子聚丙烯酰胺(CP3),羧甲基纤维素(CMC)和有机絮凝剂HSPA对细粒一水硬铝石、高岭石、伊利石和叶腊石4种单矿物以及人工混合矿的絮凝性能．结果表明,在絮凝能力上,其顺序依次为:AP7... 详细信息

采用沉降试验法系统地考查了阴离子聚丙烯酰胺(AP7),阳离子聚丙烯酰胺(CP3),羧甲基纤维素(CMC)和有机絮凝剂HSPA对细粒一水硬铝石、高岭石、伊利石和叶腊石4种单矿物以及人工混合矿的絮凝性能．结果表明,在絮凝能力上,其顺序依次为:AP7≈CP3≈HSPA> CMC;在选择性上,其顺序依次为:HSPA>CP3>CMC>AP7.以HSPA为絮凝剂,碳酸钠为矿浆分散剂,在pH为9.5-10范围內,当HSPA用量为7 g／t,Na2CO3用量5 kg／t时,对铝硅质量分数比(ω(Al)／ω／(Si))为5．68的矿石,经3次絮凝分离,取得了精矿铝硅质量分数比为8.9, Al2O3回收率86．98％的良好指标.新型絮凝剂HSPA是一水硬铝石型铝土矿较适宜的选择性絮凝分选药剂。

关键词：絮凝剂沉降铝土矿选择性絮凝铝硅质量分数比

基于最佳扫描行快速搜索策略的线阵推扫式影像微分纠正算法

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测绘学报 2013年第6期42卷 861-868页

作者：耿迅徐青邢帅蓝朝桢侯一凡信息工程大学地理空间信息学院 61363部队地理信息工程国家重点实验室

线阵推扫式影像的几何纠正是当前海量遥感影像数据处理的难点与性能瓶颈。基于严密几何模型对线阵影像进行微分纠正是生成各级影像产品的基础,其核心是地面点的反投影,即确定地面点对应的最佳扫描行。传统的最佳扫描行搜索算法基于像方... 详细信息

线阵推扫式影像的几何纠正是当前海量遥感影像数据处理的难点与性能瓶颈。基于严密几何模型对线阵影像进行微分纠正是生成各级影像产品的基础,其核心是地面点的反投影,即确定地面点对应的最佳扫描行。传统的最佳扫描行搜索算法基于像方的共线方程迭代计算,效率低,实用化程度不高。本文基于严密几何模型提出一种适用于大数据量线阵影像微分纠正的最佳扫描行快速搜索策略,利用扫描行投影面进行物方几何约束,通过判断物方点到扫描行投影面的距离定位最佳扫描行。由于线阵列CCD像元并非严格按照一条直线排列,笔者讨论了CCD线阵的分段处理以及分段投影面的确定方法。利用机载ADS40、火星快车HRSC线阵影像进行试验。结果表明,本文方法仅需少量几次物方空间解析几何迭代计算即可精确定位最佳扫描行,计算效率相比基于像方的搜索方法提高了8倍以上,线阵影像微分纠正速度提升了6倍以上。

关键词：线阵推扫式影像微分纠正反投影最佳扫描行搜索 ADS40 HRSC

Design of a high sensitivity and wide range angular rate sensor based on exceptional surface

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Chinese Physics B 2024年第8期33卷 277-286页

作者：丁鑫圣刘文耀王师贤陶煜周彦汝白禹刘来邢恩博唐军刘俊 State Key Laboratory of Dynamic Measurement Technology North University of ChinaTaiyuan 030051China Shanxi Province Key Laboratory of Quantum Sensing and Precision Measurement North University of ChinaTaiyuan 030051China

It is found that when the parity–time symmetry phenomenon is introduced into the resonant optical gyro system and it works near the exceptional point,the sensitivity can in theory be significantly amplified at low angular ***,in fact,the exceptional point is easily disturbed by external environmental variables,which means that it depends on harsh experimental environment and strong control ability,so it is difficult to move towards practical ***,we propose a new angular rate sensor structure based on exceptional surface,which has the advantages of high sensitivity and high *** system consists of two fiber-optic ring resonators and two optical loop mirrors,and one of the resonators contains a variable ratio coupler and a variable optical *** theoretically analyze the system response,and the effects of phase and coupling ratio on the system ***,compared with the conventional resonant gyro,the sensitivity of this exceptional surface angular rate sensor can be improved by about 300 times at low *** addition,by changing the loss coefficient in the ring resonator,we can achieve a wide range of 600 rad/*** scheme provides a new approach for the development of ultra-high sensitivity and wide range angular rate sensors in the future.

关键词： exceptional surface exceptional points ring resonator angular rate sensing rotational direction recognition wide operating range