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review of the dynamic stiffness method for free-vibration analysis of beams

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Transportation Safety and Environment 2019年第2期1卷 106-116页

作者： J.r.Banerjee Department of Mechanical Engineering and Aeronautics School of MathematicsComputer Science and EngineeringCityUniversity of LondonLondonEC1V 0HBUnited Kingdom

The application of the dynamic stiffness method(DSM)for free-vibration analysis of beams is surveyed in this *** historical development of the DSM,which has taken place in several stages,is discussed in detail with reference to the free-vibration problems of *** particular,the suitability of the DSM in solving the free-vibration problems of beams through the application of the well-known Wittrick–Williams algorithm as a solution technique is *** literature concerning homogeneous isotropic metallic beams,for which the DSM is well established,is reviewed first,after which,with the rapid and ongoing emergence of advanced composite materials,the development of the DSM in solving the free-vibration problems of anisotropic beams is *** free-vibration analysis of functionally graded beams using the DSM is also *** survey covers the DSM application for free-vibration analysis of a wide range of beams,including sandwich beams,rotating beams,twisted beams,moving beams and bending-torsion coupled beams,amongst *** aspects of the contributions made by the author and his research team are also ***,the future potential of the DSM in solving complex engineering problems is projected.

关键词： dynamic stiffness method Wittrick-Williams algorithm free-vibration analysis

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“阳光市长”

疯狂英语（新悦读） 2022年第11期 28-30,74页

作者： Cathy free 不详

如果天气允许的话,艾尔每天早上4:30起床,开车行驶10余公里到海滨,在那里待2个小时。主题语境:人与社会篇幅:331词建议用时:6分钟~1Almost eight years ago, Al Nixon decided to begin each day from a bench with a wonderful view of... 详细信息

如果天气允许的话,艾尔每天早上4:30起床,开车行驶10余公里到海滨,在那里待2个小时。主题语境:人与社会篇幅:331词建议用时:6分钟~1Almost eight years ago, Al Nixon decided to begin each day from a bench with a wonderful view of the St. Petersburg, Florida waterfront (海滨).

关键词： wonderful decided Florida

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初夏波扒猎鲈心得

垂钓 2018年第7X期18卷 32-37页

作者：雨花free

每年到了春末夏初时节,都是一年之中水面系拟饵又可以大展拳脚的时节。从这个时候开始,水面系拟饵将成为我每次出钓必不可少的钓组之一,而在水面拖拉机、浮水铅笔、波扒、BASS蛙等各式各样的水面系拟饵之中,我更青睐于波扒。使用浮水铅... 详细信息

每年到了春末夏初时节,都是一年之中水面系拟饵又可以大展拳脚的时节。从这个时候开始,水面系拟饵将成为我每次出钓必不可少的钓组之一,而在水面拖拉机、浮水铅笔、波扒、BASS蛙等各式各样的水面系拟饵之中,我更青睐于波扒。使用浮水铅笔作钓需要不停下压手低抽,使其走出'之'字,手腕很容易疲劳,而波扒的操作负荷则相对较低。回过头来再看看水面拖拉机,这种钓组的操控要领是落水即收。

关键词：尼龙线窗口期

关于Pre-spawn阶段作钓模式的一些思路——与55厘米巨鲈的亲密接触

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垂钓 2017年第4X期17卷 26-31页

作者：雨花free 江苏

我们在路亚鲈鱼时,有一个非常重要的知识点需要掌握,那就是'鲈鱼六季'。有人可能会问:一年之中只有四个季节,而路亚鲈鱼怎么会分为六季呢?在这里我想告诉大家,除了正常的夏、秋、冬三个季节之外,很多路亚钓手会将短短的一个春季分为鲈... 详细信息

我们在路亚鲈鱼时,有一个非常重要的知识点需要掌握,那就是'鲈鱼六季'。有人可能会问:一年之中只有四个季节,而路亚鲈鱼怎么会分为六季呢?在这里我想告诉大家,除了正常的夏、秋、冬三个季节之外,很多路亚钓手会将短短的一个春季分为鲈鱼的产卵前季、产卵中季和产卵后季这三个小季节。

关键词： Pre-spawn 深水区浅水区

Enhancing Dehydration Performance of Isopropanol by Introducing Intermediate Layer into Sodium Alginate Nanofibrous Composite Pervaporation Membrane

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Advanced Fiber Materials 2019年第2期1卷 137-151页

作者： Peiyun Li Cheng Cheng Ke Shen Tonghui Zhang Xuefen Wang benjamin S.Hsiao State Key Lab for Modification of Chemical Fibers and Polymer Materials Donghua UniversityShanghai 201620People’s Republic of China Department of Chemistry Stony Brook UniversityStony BrookNY 11794USA

A novel three-tier composite membrane based on highly porous nanofibrous substrate was demonstrated for efficient iso-propanol dehydration by ***,polyethyleneimine(PEI)modified graphene oxide(GO)sheets were vacuum-assistant assembled onto porous electrospun polyacrylonitrile(PAN)nanofibrous substrate to achieve a smooth,hydrophilic and compact PEI-GO intermediate *** introduction of PEI chains endowed GO interlayer with sufficient interaction for bonding adjacent GO nanosheets to enhance stability in water/isopropanol mixture and also with the ascended inter-lamellar space to improve the water-sorption ability due to the abundant active amino *** from PEI-GO layer,a defect-free sodium alginate(SA)skin layer could be facilely manufactured with elaborately controlled thickness as thin as possible in order to reduce mass transfer resistant and enhance permeability ***,the interlayer would also contribute to enhance interfacial adhesion to promote the structure integrity of three-tier thin-film nanofibrous composite(TFNC)membrane in pervaporation dehydration *** fine-tuning of membrane preparation process,the SA/PEI(75)-GO-60/PAN TFNC membrane exhibited competitive pervaporation performance with the permeate flux of 2009 g/m2 h and the separation factor of 1276 operated at 70°C for dehydration of 90 wt%isopropanol *** unique three-tier composite membrane structure suggested an effective and facile approach to design novel membrane structure for further improvement of pervaporation performance.

关键词： Polyethyleneimine modified graphene oxide Intermediate layer Thin-film nanofibrous composite membrane Pervaporation membrane

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《魔兽》战报

家庭电脑世界 2002年第9期 146-147页

作者： free

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四月鲈鱼进行时

垂钓 2017年第6X期17卷 28-33页

作者：雨花free 不详

四月可能是我一年之中最爱出发作钓鲈鱼的月份了,因为在这个月份里,南京的气温一般都可以达到20℃以上,而这个温度所带来的效应正是大量鲈鱼进入产卵的高峰季。在这个时间节点上,你可能在一片水域里同时钓到产前、产中以及产后的鲈鱼,... 详细信息

四月可能是我一年之中最爱出发作钓鲈鱼的月份了,因为在这个月份里,南京的气温一般都可以达到20℃以上,而这个温度所带来的效应正是大量鲈鱼进入产卵的高峰季。在这个时间节点上,你可能在一片水域里同时钓到产前、产中以及产后的鲈鱼,多样的形态带来的则是多样的标点和咬口,所以在此时出钓会非常有意思。

关键词：产卵期油菜花进行时

Ultra-high suppression microwave photonic bandstop filters

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Chinese Science Bulletin 2014年第22期59卷 2684-2692页

作者： David Marpaung Blair Morrison Mattia Pagani ravi Pant benjamin J.Eggleton Centre for Ultrahigh Bandwidth Devices for Optical Systems (CUDOS) the Institute of Photonics and Optical Sciences (IPOS) School of Physics University of Sydney Sydney NSW 2006 Australia

A bandstop radio frequency(rF)filter can enhance the capabilities of rF communication systems by removing unwanted signal components such as distortion,or *** modern cognitive radio systems,frequency agile filters are desired to block interferers with dynamically changing frequencies and *** filters should be tunable over a broad frequency range,and they should be capable of suppressing very strong signals with a high *** simultaneously meet these requirements with traditional rF filters are highly *** photonic(MWP),a technology that primary deals with the generation,distribution,and processing of high speed rF signals using photonic techniques and components,is promising for creating frequency agile rF ***,traditional MWP filters are lacking the high resolution and peak suppression exhibited by state-ofthe-art rF electrical *** recently introduced a new class of MWP notch filter which is free from this *** scheme allowed the creation of anomalously high suppression MWP notch filter from virtually any kind of optical resonance,irrespective of its type(gain or absorption),or its *** enabled,for the first time,simultaneous optimization of the MWP filter resolution,peak attenuation,and frequency tuning *** this paper,we present the analysis of notch filter response creation using the novel sideband processing *** thenshow the applicability of this technique to a wide range of optical *** compare simulated and experimental results of the notch filter response created using three types of optical filter commonly used in MWP signal processing,namely stimulated Brillouin scattering(SBS),an integrated optical ring resonator(Orr),and a phase-shifted fiber Bragg-grating(FBG).

关键词： rF滤波器微波光子陷波滤波器光学滤波器受激布里渊散射 rF信号光子技术频率捷变

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The Classification of Torsion-free TI-Groups

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Algebra Colloquium 2022年第4期29卷 595-606页

作者： ryszard r.Andruszkiewicz Mateusz Woronowiczt Faculty of Mathematics University of Bialystok 1MCiolkowskiego Street15-245 BialystokPoland

An abelian group A is called a TI-group if every associative ring with the additive group A is *** filiality of a ring r means that the ring r is associative and all ideals of any ideal of r are ideals in *** this paper,torsion-free TI-groups are described up to the structure of associative nil *** is also proved that,for torsion-free abelian groups that are not associative nil,the condition TI implies the indecomposability and *** paper contains constructions of 2^(■o)such groups of any rank from 2to 2^(■o)which are pairwise non-isomorphic.

关键词： torsion-free abelian group filial ring associative ring commutative ring additivegroupsof rings