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航空发动机进气畸变诱导叶片振动的研究 被引量:7
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作者 杜少辉 陆山 《航空发动机》 2003年第3期30-34,共5页
介绍了进气畸变导致的叶片振动响应的一般分析方法 ,讨论了引起叶片振动响应的周向总压畸变导致的激振力谐波的计算方法 ,并结合某型发动机叶片试验结果和计算结果进行对比 。
关键词 航空发动机 进气畸变 叶片 动响应 谐波激振
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一种结构振动响应再分析方法
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作者 朱亚军 宋海平 《南京化工大学学报》 2000年第6期47-50,共4页
利用初始振动响应分析结果 ,研究了在谐波或周期激振力作用下结构振动响应再分析方法 ,该方法以机械阻抗法为基础 ,采用矩阵级数展开形式建立了结构设计参数变化后的振动响应再分析方法。
关键词 结构 动响应 再分析 谐波激振 周期
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不同轨道激扰下柔性轮对重载货车垂向振动特性分析 被引量:1
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作者 朱红霞 刘红军 +2 位作者 张成成 王鹏 王翠艳 《机械设计与研究》 CSCD 北大核心 2022年第4期87-93,共7页
为了分析轮对弹性振动对重载货车动力学性能的影响,研究了考虑柔性轮对的重载货车垂向振动响应。建立轮对有限元模型,导入UM软件建立货车刚柔耦合动力学模型,利用线路实测数据验证了模型的有效性。基于实测数据分析了不同服役阶段车轮... 为了分析轮对弹性振动对重载货车动力学性能的影响,研究了考虑柔性轮对的重载货车垂向振动响应。建立轮对有限元模型,导入UM软件建立货车刚柔耦合动力学模型,利用线路实测数据验证了模型的有效性。基于实测数据分析了不同服役阶段车轮多边形几何特征,得到车轮径向偏差和谐波阶次的演变规律。在谐波激振、轨道短波激励以及车轮不圆激励下,仿真分析了货车模型的轮对垂向加速度、轮轨垂向力响应特性。结果表明:随着运营里程的增加,车轮径向偏差值增大,车轮不圆阶次逐渐向高阶发展。谐波波长越短对轮对弹性振动影响越大;短波轨道激励下刚柔耦合货车模型在中频段(25~50)Hz内的振动能量比刚性货车模型小30%左右;服役初期和后期的车轮不圆激励下,轮对在高频范围(300~500)Hz的弹性振动容易被激发,且后者引起的轮对垂向振动相比刚性货车模型振动差异显著。 展开更多
关键词 重载货车 柔性轮对 谐波激振 短波 车轮多边形
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Electromagnetic simulation and experimental analysis of microwave heaters for asphalt pavements 被引量:3
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作者 朱松青 张志胜 史泰龙 《Journal of Southeast University(English Edition)》 EI CAS 2011年第4期410-416,共7页
In order to study the thermoelectric efficiency of microwave heating and reproduction of asphalt pavements and the uniformity of reproduction temperature distribution, a waveguide excitation cavity is designed and app... In order to study the thermoelectric efficiency of microwave heating and reproduction of asphalt pavements and the uniformity of reproduction temperature distribution, a waveguide excitation cavity is designed and applied to the structural design of a microwave heater. The structural sizes of the incentive cavities are determined based on the waveguide transmission line theory. Using IE3D software, electromagnetic simulations are respectively carried out in four different situations, including the distances between the magnetron probes (antennas) and a short-circuit board, different horn electric lengths and aperture sizes, different dielectric properties of the asphalt mixture, and the distances between the asphalt surface and the mouth cavity. The results show that, when the distance between the magnetron probe and the short-circuit board is 32.5 ram, it is the best installation site; reduction of aerial length is the main factor in improving the heating uniformity. When the aggregate is limestone, the best heating effect can be produced. Maximum radiation efficiency can be realized by adjusting the space between the heater radiation port and the asphalt pavement. The experimental results of asphalt mixture heating in four different situations have a substantial agreement with the simulation results, which confirms that the developed microwave heater can achieve better impedance matching, thus improving the quality and efficiency of heating regeneration. 展开更多
关键词 microwave heater excitation cavity structural design electromagnetic simulation temperature distribution experimental analysis
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Mean First Passage Time for System with Fluctuating Potential Barrier and Coupled Noise
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作者 LI Jing-Hui HAN Yin-Xia 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第3期517-519,共3页
In this paper we study the mean first passage time (MFPT) over a fluctuation potential barrier driven by a coupled noise. It is shown that the MFPT over the fluctuation potential barrier displays resonant activation... In this paper we study the mean first passage time (MFPT) over a fluctuation potential barrier driven by a coupled noise. It is shown that the MFPT over the fluctuation potential barrier displays resonant activations as the function of the flipping rate of the fluctuation potential barrier, and as the function of the dichotomous noise transition rate. 展开更多
关键词 mean fist passage time resonant activation coupled noise
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Calculation of coupling efficiency for rectangular waveguide CO_2 laser by fresnel approximation
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作者 Hussain Badran 田兆硕 王骐 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2003年第3期335-337,共3页
Theoretical analyses have been performed to describe the coupling losses for a plane mirror in rectangular waveguide resonator for an arbitrary waveguide mode as a function of the Fresnel number for several values of ... Theoretical analyses have been performed to describe the coupling losses for a plane mirror in rectangular waveguide resonator for an arbitrary waveguide mode as a function of the Fresnel number for several values of the aspect ratio by using Fresnel approximation. 展开更多
关键词 rectangular waveguide RESONATOR coupling efficiency
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Wide and Fast Wavelength-Swept Fiber Lasers Based on Dispersion Tuning and Their Application to Optical Coherence Tomography 被引量:2
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作者 Shinji YAMASHITA Yuya TAKUBO 《Photonic Sensors》 SCIE EI CAS 2013年第4期320-331,共12页
We recently proposed a new class of wavelength-swept lasers for swept-source optical coherence tomography (SS-OCT). It uses the same gain medium with the conventional swept lasers, but does not require any tunable f... We recently proposed a new class of wavelength-swept lasers for swept-source optical coherence tomography (SS-OCT). It uses the same gain medium with the conventional swept lasers, but does not require any tunable filters. It is based on a principle called "dispersion tuning", in which a highly dispersive medium is inserted in the laser cavity, and loss/gain modulation is applied to mode-lock the laser. Since the cavity contains no mechanical components, such as tunable filters, we could achieve the very high sweep rate. In this review paper, we describe the principle of the dispersion-tuned swept lasers in detail and present our recent work on the application to the SS-OCT system. 展开更多
关键词 OCT swept lasers dispersion tuning
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Electromagnetically Induced Transparency of Two Intense Circularly-Polarized Lasers in Cold Plasma: Beat-Wave Second Harmonic Effect
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作者 N.Sepehri Javan L.Akbari 《Communications in Theoretical Physics》 SCIE CAS CSCD 2014年第2期246-252,共7页
In the present paper the problem of nonlinear interaction of two mildly-relativistic circularly polarized lasers in a cold plasma is studied in order to investigate electromagneticaily induced transparency (EIT). Ba... In the present paper the problem of nonlinear interaction of two mildly-relativistic circularly polarized lasers in a cold plasma is studied in order to investigate electromagneticaily induced transparency (EIT). Based on a relativistic kinetic model, by expansion of relativistic Lorentz factor in terms of lasers amplitude, we obtain the coupled nonlinear dispersion relations. It is observed that due to resonance in the second harmonic of plasma beat-wave, the new EIT pass-band is created in the high intensities of lasers. The effect of amplitude and frequency variation on the dispersion is numerically investigated. 展开更多
关键词 EIT laser-plasma interaction beat-wave DISPERSION second harmonic
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