Modal Amplitude Stability Analysis and its application to brake squeal

In the present study, a new approach is proposed to predict the occurrence of squeal in brake systems. This strategy, called Modal Amplitude Stability Analysis (MASA), is based on the calculation of the first harmonic state-space system of nonlinear original equations using a specific linearization of the nonlinear contact forces at the frictional interfaces. An estimation of the occurrence and generation of increasing self-excited vibration is proposed on the basis of monitoring and the evolution of the real parts of the dynamic system considered as a function of modal amplitudes.     

Frequency Map分析在合肥光源GPLS上的应用

介绍了Frequency Map Analysis在合肥光源上的应用,通过粒子跟踪得到加入六极以及八极磁铁后合肥光源的tune漂移,根据得到的tune图分析高阶共振情况计算发现通用光源模式(GPLS)lattice处在弱共振带上.     

FMA在BEPCⅡ上的应用

介绍了基于AT的FMA方法在BEPCⅡ上首次较系统的应用. 将AT分析结果与MAD和SAD程序比较, 吻合较好. 考虑高频腔和辐射阻尼效应, 利用FMA分别对BEPCⅡ对撞模式和注入模式进行分析, 揭示了相应的单粒子动力学, 为进一步优化提供指导和依据. 结果显示纵向横向耦合共振可能会对粒子动力学产生较大影响.     

Active Anomalous Transmission and Its Application in Compensating Waveform Distortions

In theory, engineered anomalous transmission in passive materials and waveguide devices can be used to compensate for waveform distortions. However, they suffer from inherent dissipation. Recently, active non-Foster elements with imaginary immittance monotonically decreasing with frequency have shown important potentials in broadening bandwidths of electromagnetic devices. So far, they are implemented based on negative impedance convertors(NICs) loaded with Foster devices. This makes them intrinsically one-port elements and thus cannot be used to compensate for distortions of signals. We construct a two-port network with a non-Foster transmission coefficient based on an unconventional use of NICs. Simulation and experiments show that it can compensate for extremely distorted signals. The proposed method can be used to broaden existing applications in different areas such as antennas, circuits and systems, and physical-layer signal processing.     

Modal quantum logic and its dialogic foundation

In this paper we investigate a modal calculus of quantum metalogic which is complete and sound with respect to a dialogic semantics. This calculus calledM _eff(Q _eff) has three parts: one covering the formal metalogic, one reflecting the calculus of the object language, and one which is a link between object language and metalanguage. This third part is invariant with respect to a variation of the object language     

Reinforced Concrete Fracture Diagnostics under Conditions of Bending by Parameters of the Electric Response to an Impact Action

Technical Physics - Regularities of changes in the stress-strain state of reinforced concrete in the process of testing for four-point bending have been studied. The change in characteristics of...     

音频分析软件在声学中的应用

介绍如何利用计算机通过基于声卡的虚拟仪器来演示各种声学现象，使学生从“看声音”中得到学习的乐趣，加深对声学基本概念的理解。     

Regression Analysis of Confocal FRAP and its Application to Diffusion in Membranes

In most biological processes, diffusion plays a critical role in transferring various bio-molecules to transfer desirable locations in an effective and energy-efficient manner. How fast molecules are transferred is measured by diffusion coefficients. Since each bio-molecules, in particular, signaling molecules have their unique diffusion coefficients and quantifying the diffusion coefficients help us to understand various time scales of both physiological and pathological processes in biological systems. Moreover, since diffusion profiles of a diffusant vary in different micro-environments of cell membranes, accurate diffusion coefficient also can provide a good picture of membrane landscapes as well as interactions of different membrane constituents. Currently, only a few experimental methods are available to assess the diffusion coefficient of a biomolecule of interest in live cells including Fluorescence Recovery After Photobleaching (FRAP). FRAP was developed to study diffusion processes of biomolecules in the cell membranes in the 1970s. Albeit its long history, the main principle of FRAP analysis has remained unchanged since its inception: fitting FRAP data to a theoretical diffusion model for the best fitting diffusion coefficient or using the relation between the half time of recovery and ROI size. In this study, we developed a flexible yet versatile confocal FRAP data analysis framework based on linear regression analysis which allows FRAP users to determine the diffusion from either single or multiple FRAP data points without data fitting. We also validated this approach for a series of fluorescently labeled soluble and membrane-bound proteins and lipids.

     

Application of Microwave Nonstationary Spectroscopy for Noninvasive Medical Diagnostics

We consider an application of the method of microwave nonstationary gas spectroscopy for analytical studies of multicomponent gas mixtures using exhaled air as an example. The methods used for studying multicomponent gas mixtures are reviewed. We describe subterahertz and terahertz nonstationary gas spectrometers based on the effect of freely damped polarization. The results of test measurements of nitric oxide (NO) in the 2-mm wavelength range are presented. Methods for studying the response dynamics are developed. The prospects of using the method of microwave nonstationary gas spectroscopy in the subteraherz and teraherz ranges are shown. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 51, No. 6, pp. 545–551, June 2008.     

基于近红外频域自适应分析法的电煤发热量模型研究（英文）

目前由于部分电站锅炉所用到的燃煤大多为配煤,在有些情况下,其复杂的物理化学特性导致难以获得高精确度的常规近红外定量分析模型,这给电煤发热量的在线检测带来了一定困难。针对该问题,深入研究了电煤近红外光谱时域和频域特征,提出一种能够通过全局优化策略自动在频域内建立最优近红外定量分析模型的新方法—频域自适应分析法。该方法首先将时域近红外光谱通过快速傅里叶变换转换为频域近红外信号;然后采用有效光谱能量率得到合适的频域信息范围;接着根据近红外光谱频域下的相关系数谱图、方差谱图以及谐波在频域中的坐标合理构建了频域信息量评价参数,利用该参数对模型输入变量的种群位置进行初始化;最后采用频域分区搜索和综合性能评价函数得到最佳建模方案。与此同时,结合电煤煤粉近红外图谱的特性,并以其发热量为待测目标对该方法进行了验证,取得相对较好实验效果,与传统方法主成分回归、偏最小二乘回归、反向传播神经网络以及基于遗传算法的偏最小二乘回归和支持向量机回归相比,该方法预测精度更高,并且有效避免了频域随机搜索潜在的过拟合和虚假有效模型的弊端,具有良好的应用前景。此外,该方法也可推广用于其他类型的光谱定量分析。     

Electric polarization in crystals and its response to thermal and elastic perturbations

The basic properties of electric polarization response in crystalline dielectrics are theoretically analysed. Spontaneous polarization, pyroelectricity, piezoelectricity, flexoelectricity (polarization response to strain gradient) and thermopolarization effect (polarization response to temperature gradient) are discussed on the basis of a unified approach. Special attention is paid to the problem of the adequate theoretical definition of these phenomena. The effect of the sample termination on the polarization response is considered in detail.     

Diagnostics of High-Temperature,High-Density Plasma by Radiation Analysis

This article will be restricted to the diagnostics of laboratory plasmas having an average particle energy of higher than 30 eV per particle and a density of greater than 10¹⁹ particles per cm³. Common features of such plasmas related to applied spectroscopy are their complete ionization, the high excitation and ionization levels the particles, the large emission coefficients for continuum radiation over a wide spectral range from the X-ray region up to the infrared, their small size, high temperature and density gradients to the environment, and their transient nature.     

水平变化浅海声波导中模态特征频率与声源距离被动估计

针对水平变化浅海声波导中声源宽容性被动测距问题,理论分析了海底地形水平缓变浅海波导中卷绕变换基础上的低频声场特征频率.推导了绝对硬海底时水平变化波导中声场模态时频到达结构以及模态瞬时相位的表达式,由该表达式给出了特征频率与收发距离的变化关系,进而提出了水平变化浅海波导中声源距离被动估计的修正方法,通过仿真和实验对理论与方法进行了验证.     

低频信号发生器在感抗、容抗实验中的应用

普通高中课程标准实验教科书《物理》选修3-2第五章第三节"电感和电容对交变电流的影响",在讲电感对频率变化的交流的影响时是这样描述的:"实验和理论分析都表明,线圈的自感系数越大、交流的频率越高,电感对交流电的阻碍作用就越大,也就是说,线圈的感抗越大."同样地,在讲电容对频率变化对交流电的影响时也是这样描述的:"理论和实验分析都表明,电容器的电容越大,交流的频率越高,电容器对交流的阻碍作用就越小,也就是说,电容器的容抗就越小."     

Frequency multi-mode lens for atoms and molecules: Application to nanofabrication

We present a frequency multi-mode lens with corrected spherical aberration suitable for focusing of both atoms and molecules. The lens is formed by superposing of several harmonics of standing light waves in such a way that to create harmonic potential for all particles crossing the light field. The application to nanolithography is discussed emphasizing the possibility to improve the contrast of deposited structures.     

Distortions of videofiberoscopy imaging: Reconsideration and correction

An analysis was made of the optical distortion of a lens system of a fiberscope and the distortion related to lens-object angles and lens-object distances used in laryngeal flexible endoscopic examinations. The optical distortion was systematic and, therefore, could be corrected through computer processing once the calibration was made. Similarly, the distortion related to the lens-object angle and distance varied systematically depending on distance and angle and, therefore, could be predicted if those parameters were measured simultaneously. The correction of those distortions of videofiberoscopic image is demonstrated, and a procedure for recording and measuring laryngeal images that minimizes measurement error due to those distortions is suggested.     

Modelling and Analysis of Modal Behaviour in SOI Slot Waveguides

Mode behaviour for SOI slot waveguides is modelled and analysed using a numerical full vectorial method based on the film mode matching method （MMM）. Only the quasi-TE mode is investigated. Waveguide heights and slot widths, as well as silicon widths are properly chosen with respect to the single mode behaviour in the slot region. Comparison between the effective index method and our side loss method shows that our single mode condition is creditable. The optical power confinement in slot region for the quasi-TE mode is also studied and presented. We demonstrate that the maximum achievable optical power confinement Pslot and the maximum normalized average optical intensity Islot are 42% and 26um^-2, respectively.