单人Bounce荷载下楼盖结构加速度反应谱设计

Bounce指双脚不离地的人体上下往复运动,是一种常见的有节奏人致激励。采用先进的无线测力鞋垫技术收集了175条bounce荷载曲线,计算每条荷载曲线的单自由系统加速度反应谱,在此基础上提出了设计反应谱分段表达式,主要分为三段：对应bounce一阶主频范围2～3.5 Hz的第一平台段、对应二阶主频范围4～7 Hz的第二平台段以及对应高阶频率的下降段,由试验数据分析给出了两个平台段的不同保证率下的代表值以及下降段参数。文中给出了设计反应谱的详细使用步骤,并通过大跨楼盖试验模型验证了方法的准确性。

单人Bounce荷载的实验建模研究

Bounce指音乐会或体育比赛中常见的观众双脚不离地的身体有节奏的上下往复运动。利用测力板以及无线测力鞋垫,开展了单人在不同频率下的Bounce荷载的测试试验,共得到了109人次822条有效单人Bounce荷载记录。在此基础上,建立了Bounce荷载的傅里叶级数模型,给出了四阶动载因子和相位角的建议值,并与国外已有模型进行了对比分析。本文模型所模拟的Bounce荷载与实测荷载的时域特性相同,所引起的结构响应幅值一致,可供工程设计参考使用。

多人Bounce荷载下结构动力响应折减系数研究

体育比赛、演唱会中观众原地身体上下往复式的欢庆动作会引起Bounce荷载,是典型的有节奏人致动力荷载。该研究将考虑和不考虑人群协同性所计算出的结构响应的比值,定义为Bounce荷载下的结构动力响应折减系数,利用小组人群同步Bounce荷载的实测数据,研究了折减系数随人数、结构频率和阻尼比的变化规律,并提出了对应的设计曲线及表达式。应用于实际结构响应计算时,首先由反应谱法计算单人Bounce荷载下结构的动力响应,将其乘以总体重并考虑振型值影响后,再乘以对应的折减系数,即可实现考虑协同性的人群Bounce荷载下结构动力响应的快速计算,算例分析表明了上述步骤及所建议的折减系数的合理性。

Bouncing Ball模型的弱混沌性

用异于传统的方法 ,作出BouncingBall映射不变流形的对称流形 ,从而成功地将稳定流形与不稳定流形的位置进行比较 .应用 [1]关于弱横截与弱混沌的有关概念及定理 ,给出了Bounc ingBall映射产生弱混沌的较为一般的参数区域 ,进一步揭示了BouncingBall映射的动力学行为 .

Bouncing Ball映射的弱混沌性

在文［1］引进的弱横截与弱混沌等概念的基础上，利用微分同胚不变流形的旋转性讨论了BouncingBall映射的混沌性与弱混沌性，揭示了BouncingBall映射的动力学行为．

Matter Bounce宇宙模型研究

通过描述宇宙学的发展历史和现状,指出大爆炸理论和暴涨理论虽然有许多优点,可以解释许多现象,但它们并不是完美无缺,无懈可击,仍然有一些无法解释的问题。而matter bounce宇宙模型是一个可以取代前两种理论的模型,可以得到与宇宙观测相吻合的结论,因此研究这个模型是非常有意义的。

Bouncing Ball映射的双曲不变集

对碰撞恢复系数范围为 0 <α<1的“弹跳球 (Bouncing Ball)”映射 ,通过适当的坐标变换 ,给出了双曲不变集存在的严格条件 .

Multi-Bounce ATR-FTIR结合Gram-Schmidt正交化法计算烟用香精相似度

采集2种不同风格特征烟用香精的Multi-Bounce Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy(Multi-Bounce ATR-FTIR)指纹图谱,运用主成分分析法各筛选出30条光谱,结合Gram-Schmidt正交化方法,分别建立了2类不同风格特征烟用香精的相似度鉴别模型。使用鉴别模型对未知样品进行相似度计算,并评价使用效果。结果显示,当相似度高于90%时,可以判定属于同一类香精,且相似度越高,风格特征越接近;当相似度低于90%时,可以判定不属于同一类香精,且相似度越低,风格特征的差异越显著。

GROUND BOUNCING NOISE REDUCTION TECHNIQUE CONSIDERING WAKE-UP DELAY IN MTCMOS CIRCUITS

Multi-Threshold CMOS(MTCMOS) is an effective technique for controlling leakage power with low delay overhead.However the large magnitude of ground bouncing noise induced by the sleep to active mode transition may cause signal integrity problem in MTCMOS circuits.We propose a methodology for reducing ground bouncing noise under the wake-up delay constraint.An improved two-stage parallel power gating structure that can suppress the ground bouncing noise through turn on sets of sleep transistors consecutively is proposed.The size of each sleep transistor is optimized by a novel sizing algorithm based on a simple discharging model.Simulation results show that the proposed techniques achieve at least 23% improvement in the product of the peak amplitude of ground bouncing noise and the wake-up time when compared with other existing techniques.

Experimental Study of a Sphere Bouncing on the Water

In this paper,the fow physics and impact dynamics of a sphere bouncing on a water surface are studied experimentally.During the experiments,high-speed camera photography techniques are used to capture the cavity and free surface evolution when the sphere impacts and skips on the water surface.The infuences of the impact velocity(v_(1))and impact angle(θ_(1))of the sphere on the bouncing fow physics are also investigated,including the cavitation evolution,motion characteristics,and bounding law.Regulations for the relationship between v_(1)andθ_(1)to judge whether the sphere can bounce on the water surface are presented and analyzed by summarizing a large amount of experimental data.In addition,the efect ofθ_(1)on the energy loss of the sphere is also analyzed and discussed.The experiment results show that there is a ftted curve of v_(1)=17.5θ_(1)−45.5 determining the relationship between the critical initial velocity and angle whether the sphere bounces on the water surface.

Corotating drift-bounce resonance of plasmaspheric electron with poloidal ULF waves

The purpose of this paper is to understand how low energy plasmaspheric electrons respond to ULF waves excited by interplanetary shocks impinging on magnetosphere. It is found that both energy and pitch angle dispersed plasmaspheric electrons with energy of a few eV to tens of eV can be generated simultaneously by the interplanetary shock. The subsequent period of successive dispersion signatures is around 40 s and is consistent with the ULF wave period(third harmonic). By tracing back the energy and pitch angle dispersion signatures, the position of the electron injection region is found to be off-equator at around -32° in the southern hemisphere. This can be explained as the result of injected electrons being accelerated by higher harmonic ULF waves(e.g. third harmonic) which carry a larger amplitude electric field off-equator. The dispersion signatures are due to the flux modulations(or accelerations) of " local" plasmaspheric electrons rather than electrons from the ionosphere. With the observed wave-borne large electric field excited by the interplanetary shock impact, the kinetic energy can increase to a maximum of 23 percent in one bouncing cycle for plasmaspheric electrons satisfying the drift-bounce resonance condition by taking account of both the corotating drift and bounce motion of the local plasmaspheric electron.

Constraints on Deceleration Parameter of a 5D Bounce Cosmological Model from Recent Cosmic Observations

We study the constraint on deceleration parameter q from the recent SNela Gold dataset and observational Hubble data by using a model-independent deceleration parameter q（z） = 1/2 - a/（1 ＋ z）^b under the flve-dimensional bounce cosmological model. For the cases of SNeIa Gold dataset, Hubble data, and their combination, the present results show that the constraints on transition redshift ZT are 0.35-0.07^＋0.14,0.68-0.58^＋1.47,and 0.55-0.09^＋0.18 with 1σ errors,respectively.

Observational constraints on the accelerating universe in the framework of a 5D bounce cosmological model

In the framework of a five-dimensional （5D） bounce cosmological model, a useful function f（z） is obtained by giving a concrete expression of deceleration parameter q（z） = q1 ＋q2/1＋1n（1＋z） Then using the obtained Hubble parameter H（z） according to the function f（z）, we constrain the accelerating universe from recent cosmic observations： the 192 ESSENCE SNe Ia and the 9 observational H（z） data. The best fitting values of transition redshift zT and current deceleration parameter q0 are given as zT =0.65-0.12^＋0.25 and q0=-0.76-0.15^＋0.15（1σ）. Furthermore, in the 5D bounce model it can be seen that the evolution of equation of state （EOS） for dark energy Wde can cross over -1 at about z = 0.23 and the current value W0de ： =-1.15 〈 -1. On the other hand, by giving a concrete expression of model-independent EOS of dark energy Wde, in the 5D bounce model we obtain the best fitting values zT = 0 .66-0.08^＋0.11 and q0=-0.69-0.10^＋0.10（1σ） from the recently observed data： the 192 ESSENCE SNe Ia, the observational H（z） data, the 3-year Wilkinson Microwave Anisotropy Probe （WMAP）, the Sloan Digital Sky Survey （SDSS） baryon acoustic peak and the x-ray gas mass fraction in clusters.

Optimization design method of contact bounce and breakaway initial velocity for aerospace electromagnetic relay

Aerospace electromagnetic relay is an electric component that has been widely used in aerospace industry.Contact bounce and contact breakaway for initial velocity are the key parameters that have strong influence on reliability and electric life of the relay.Generally,it is difficult to optimize these two parameters simultaneously.In this paper,according to kinetics theory and structural mechanics,a dynamic reaction calculation model of the relay that describes contact bounce and breakaway for initial velocity is proposed.Under the constraints of contact gap and contact force,the optimal combination of debugging parameters is obtained by the application of orthogonal design.It considers the reduction of contact bounce and the augmentation of breakaway for initial velocity as the optimization objectives,and takes the debugging parameters as the optimization variables.All these above ensure the increase of contact breakaway for initial velocity and the decrease of contact bounce simultaneously,and contact arc erosion is also reduced.

Scattering from Rough Surfaces Using the"Shooting and Bouncing Rays" Technique

The “shooting and bouncing rays” (SBR) technique is used to analyze the electromagnetic scattering characters of ocean rough surfaces varying with time. Some numerical results are presented and compared with the method of moments, and some factors, such as the incident angle, polarization and frequency are investigated which influence on electromagnetic scattering characters of ocean rough surfaces.

Landau damping of electrons with bouncing motion in a radio-frequency plasma

One-dimensional particle simulations have been conducted to study the interaction between a radio-frequency electrostatic wave and electrons with bouncing motion.It is shown that bounce resonance heating can occur at the first few harmonics of the bounce frequency(nω_(b),n=1,2,3,...).In the parameter regimes in which bounce resonance overlaps with Landau resonance,the higher harmonic bounce resonance may accelerate electrons at the velocity much lower than the wave phase velocity to Landau resonance region,enhancing Landau damping of the wave.Meanwhile,Landau resonance can increase the number of electrons in the lower harmonic bounce resonance region.Thus electrons can be efficiently heated.The result might be applicable for collisionless electron heating in low-temperature plasma discharges.

Admissible Periodic Bouncing Solutions for A Class of Semi-linear and Non-conservative Impact Oscillators

In this paper, by using the topological degree method and some limiting arguments, the existence of admissible periodic bouncing solutions for a class of non-conservative semi-linear impact equations is proved.

Complete Coalescence, Partial Bounce and Rebound: Different Regimes Resulting from the Interaction of a Free Falling Drop with a Target Fluid

The interaction of a falling drop(diluted aqueous solution of ink in various concentrations)with a target fluid(partially degassed tap water)has been tracked by means of high-resolution video recording and photography.The experimental setup has carefully been prepared in order to preserve the axial symmetry of initial conditions.Three regimes of interaction have been identified accordingly(depending on the drop velocity as controlled by the distance of fall):rapid droplet coalescence,rebound with the conservation of the drop volume and shape,and partial coalescence.Previous findings are recovered and confirmed,and enriched with heretofore unseen observations of complex partial coalescence.An extensive set of data is reported to support understanding of the observed dynamics and their repeatability and reproducibility.The overall study has been carried out with the express intent to spur the future development of detailed mathematical models and numerical methods suited for this kind of problems.

Modified Ceiling Bounce Model for Computing Path Loss and Delay Spread in Indoor Optical Wireless Systems

This paper proposes modifications to the tradional Ceiling Bounce Model and uses it to characterize diffuse indoor optical wireless channel by analyzing the effect of transceiver position on signal propagation properties. The modified approach uses a combination of the tradional ceiling bounce method and a statistical approach. The effects of different transmitter-receiver separations and height of the ceiling on path loss and delay spread are studied in detail.

Angular Impulse and Spinning Bouncing Ball

A solid ball of mass m, size r and spin ω about an axis through its center is dropped freely from a height h on a rough horizontal plane. Assuming its angular momentum is parallel to the horizontal plane upon impact it bounces repeatedly drifting on a vertical plane. We analyze the kinematics of the bouncing ball assuming the impacts are semi-elastic without slipping. By varying the spin and relevant parameters, a robust Mathematica [1] program enables simulating the trajectories.