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Experimental and FEM Modal Analysis of a Deployable-Retractable wing

Modern Mechanical Engineering 2014年第4期4卷 183-197页

作者： P. Jia S. K. Lai w. Zhang C. w. Lim Department of Architecture and Civil Engineering City University of Hong Kong Hong Kong China Shenzhen Research Institute City University of Hong Kong Shenzhen China College of Mechanical Engineering Beijing University of Technology Beijing China Meinhardt (M & E) Ltd Hong Kong China

The aim of this paper is to conduct experimental modal analysis and numerical simulation to verify the structural characteristics of a deployable-retractable wing for aircraft and spacecraft. A modal impact test was conducted in order to determine the free vibration characteristics. Natural frequencies and vibration mode shapes were obtained via measurement in LMS Test. Lab. The frequency response functions were identified and computed by force and acceleration signals, and then mode shapes of this morphing wing structure were subsequently identified by PolyMAX modal parameter estimation method. FEM modal analysis was also implemented and its numerical results convincingly presented the mode shape and natural frequency characteristics were in good agreement with those obtained from experimental modal analysis. Experimental study in this paper focuses on the transverse response of morphing wing as its moveable part is deploying or retreating. Vibration response to different rotation speeds have been collected, managed and analyzed through the use of comparison methodology with each other. Evident phenomena have been discovered including the resonance on which most analysis is focused because of its potential use to generate large amplitude vibration of specific frequency or to avoid such resonant frequencies from a.wide spectrum of response. Manufactured deployable-retractable wings are studied in stage of experimental modal analysis, in which some nonlinear vibration resulted should be particularly noted because such wing structure displays a low resonant frequency which is a.ways optimal to be avoided for structural safety and stability.

关键词： Deployable-Retractable wing Experimental Modal Analysis FEM Mode Shapes Natural Frequency LMS Test. Lab

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喧哗与骚动

喧哗与骚动

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作者： w.·福克纳(w. Faulkner)

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Dexmedetomidine versus Ketamine for the Prevention of Emergence Agitation in Pediatric: A Prospective, Randomized, and Controlled Clinical Trial

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Open Journal of Anesthesiology 2020年第5期10卷 203-212页

作者： Elsayed Mohamed Abdelzaam Enas w. Mahdy Department of Anesthesiology Faculty of Medicine Benha University Benha Egypt

Background: This study compares the effect of dexmedetomidine versus Ketamine for the prevention of emergence agitation in children undergoing general anaesthesia. Method: 75 Children are randomly allocated into three groups. Group C: were assigned to receive normal saline. Group K: were assigned to receive Ketamine 0.25 mg/kg. Group D: assigned to receive 0.25 ug /kg of dexmedetomidine, before the end of surgery. Results: There was no statistically significant difference in demographic data and intraoperative parameters between the three groups. But as regards to time to discharge, there was a significant difference between group C, group K and group D (group C = 39.96 ± 2.84, group K = 37.28 ± 3.80, group D = 35.08 ± 3.36 and P value = 0.0002). FLACC scale was low after extubation, before leaving the operating room and on arrival to PACU (small FLACC scale in group K, D than group C). PAED scoreless in Group K and Group D than Group C (postoperative, at 10 minutes, 20 min, 30 min). Conclusion: Ketamine and dexmedetomidine reduced the incidence and severity of emergence delirium effectively when compared to normal saline, and the effects of dexmedetomidine being much superior to Ketamine.

关键词： Emergence Agitation Ketamine Dexmedetomidine

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奥塞罗

奥塞罗

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作者： w.·莎士比亚(w. Shakespeare)

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李尔王

李尔王

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作者： w.·莎士比亚(w. Shakespeare)

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Spectral and Temporal Emission Behaviors in Disordered Scattering of Rh640 Dye Solution

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Chinese Physics Letters 1997年第10期14卷 736-739页

作者： wANG He-zhou ZHAO Fu-li HUANG Xu-guang ZHENG Xi-guang wU Ming-mei w.K.LEE Institute for Laser and Spectroscopy Department of ChemistryZhongshan UniversityGuangzhou 510275 Department of Physics Chinese University of Hong KongHong Kong

The fluorescent decays and spectra of pump power density dependent emission demonstrated that the excitation power density was enhanced in Rh640 dye solution containing scattering *** in disordered scattering medium with low threshold,narrow bandwidth,and short duration was *** mechanism of this enhancement,together with the lasing properties of low threshold and narrow bandwidth,was discussed.

关键词： scattering pump narrow

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Ordovician Stratigraphy of Erhtsun,Kunming

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地质学报 1941年第Z1期 273-280页

作者： w.K.Kuo (National University of Peking)

Erhtsun is a small village about 22 km northwest of *** liesin the valley dissected by the Shalangho;flowing from southeast to northwest

关键词： Th Ordovician Stratigraphy of Erhtsun,Kunming

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基于THEMIS卫星数据的等离子体层顶位置模型

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中国科学：地球科学 2014年第10期44卷 1980-1986页

作者：刘旭刘文龙北京航空航天大学宇航学院空间科学研究所北京100191 中国科学院空间天气学国家重点实验室北京100190

利用2010～2011年的THEMIS卫星观测的卫星电位数据反演电子密度,并用来确定等离子层顶的位置,研究其与地磁指数的关系。利用观测数据得到了一个THEMIS卫星等离子体层顶位置数据库。利用该数据库建立了新的等离子体层顶位置的磁地方时经... 详细信息

利用2010～2011年的THEMIS卫星观测的卫星电位数据反演电子密度,并用来确定等离子层顶的位置,研究其与地磁指数的关系。利用观测数据得到了一个THEMIS卫星等离子体层顶位置数据库。利用该数据库建立了新的等离子体层顶位置的磁地方时经验模型,并比较了其与现有的四个等离子体层顶位置经验模型的优劣。发现新建立的等离子体层顶位置模型明显优于其余四个经验模型。在模型的三种输入参数中,Kp指数和Dst指数模型的预测效果相当,并明显优于AE指数的模型,这说明磁层的大尺度对流强度是影响等离子体层顶位置最主要的因素。

关键词：等离子体层顶地磁指数磁地方时

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秦巴山区人居生活质量研究:关注城市发展建设对相关人群的影响

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中国工程科学 2016年第5期18卷 92-99页

作者： Robert w.Marans 徐滢密歇根大学社会研究所密歇根州安娜堡市48103

地处秦巴腹地的陕南地区正在开展一项大规模的避险移民工程。此项工程意在通过涵养自然生态、推进地区产业转型和城市就业、加大新城新区建设等以达到防灾、扶贫和提高城乡居民生活水平的目的。本文建议在秦巴山区开展以评估人居生活质... 详细信息

地处秦巴腹地的陕南地区正在开展一项大规模的避险移民工程。此项工程意在通过涵养自然生态、推进地区产业转型和城市就业、加大新城新区建设等以达到防灾、扶贫和提高城乡居民生活水平的目的。本文建议在秦巴山区开展以评估人居生活质量为主题的纵向社会学研究。此项研究主要依靠当地居民从个体视角出发,对生活状况的综合主观评价来衡量移民工程的社会意义。研究重点关注三类人群:已经完成搬迁安置的新移民,尚未搬迁——其中包括在未来有移民意向的农村居民,以及移民迁入地区的原有城镇居民。此项研究可以用于监测移民工程和城乡建设的进展,分析此工程对各个社会群体民生状况的现实影响,并对当地及其他地区政府的后续的政策规划提供参考意见。以此为出发点,本文综述了在社会学领域内生活质量研究的理论发展和研究体系,并针对秦巴山区的具体状况提出了若干建议。

关键词：生活质量研究社会调查研究社会影响评价移民新城新区建设秦巴山区

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A method for solving relative dispersion of the cloud droplet spectra

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Science China Earth Sciences 2015年第5期58卷 929-938页

作者： LIU Yu LI weiLiang Chinese Academy of Meteorological Sciences

The relative dispersion of the cloud droplet spectra or the shape parameter is usually assumed to be a constant in the two-parameter cloud microphysical scheme, or is derived through statistical analysis. However, observations have revealed that the use of such methods is not applicable for all actual cases. In this study, formulas were derived based on cloud microphysics and the properties of gamma function to solve the average cloud droplet radius and the cloud droplet spectral shape parameter. The gamma distribution shape parameter, relative dispersion, and cloud droplet spectral distribution can be derived through solving the droplet spectral shape parameter equation using the average droplet radius, volume radius, and their ratio, thereby deriving an analytic solution. we further examined the equation for the droplet spectral shape parameter using the observational droplet spectral data, and results revealed the feasibility of the method. In addition, when the method was applied to the two-parameter cloud microphysical scheme of the weather Research and Forecast(wRF) model to further examine its feasibility, the modeling results showed that it improved precipitation simulation performance, thereby indicating that it can be utilized in two-parameter cloud microphysical schemes.

关键词： cloud droplet spectrum gamma distribution relative dispersion shape parameter average radius

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