基于光的反射与折射定律的表述方法推导及应用

光的反射和光的折射是几何光学应用中最基本的方法。在现代精密光学元件加工过程中,其不同的表述方法可以为光线追迹、棱镜误差分析以及棱镜装调提供不同的解决思路。介绍了光的反射定律和折射定律的传统形式表述方法,并推导了光的反射定律和折射定律的矢量、矩阵及四元数3种表述方法。通过Matlab辅助下的模拟计算,得到施密特棱镜检验光路中2个不同区域入射光线的反射在水平方向上对称分布于前表面反射像两侧,与实际应用相符,实现了矢量、矩阵和四元数表述方法在施密特棱镜检验光路中的应用。3种表述方法可以为光线追迹、棱镜误差分析以及棱镜装调提供科学、实用的解决方法。     

Experimental characterization of instrument panel buzz, squeak, and rattle (BSR) in a vehicle

Among the various elements affecting a customer’s evaluation of automobile quality, buzz, squeak, and rattle (BSR) are considered to be major factors. We propose an integrated experimental method that can be used to reduce BSR in an instrument panel module in a vehicle cabin, especially during the early design stage of vehicle development. We devised a vibration triggering system consisting of a fixture and an electromagnetic shaker to generate an input load reproducing the excitation signal from the road to the instrument panel without distortion. Potential source regions for BSR were localized using a near-field acoustic holography map obtained from near-acoustic-field visualization equipment consisting of 48 intensity-type microphones, a data-acquisition system, and its analysis software. Finally, a sound quality evaluation of BSR from the detected potential source regions was performed using sound quality metrics. These experimental procedures were applied to characterize BSR from the instrument panel in a passenger vehicle. Based on our measurements and analysis, typical main source regions for BSR on the instrument panel were identified and quantitatively evaluated in terms of physical levels and sound quality metrics. These results revealed that the proposed experimental procedure can be used as a test procedure to identify BSR issues at an early stage in the vehicle development cycle, which could ultimately reduce production costs.     

焊缝超声相控阵检测数据深度学习降噪方法

超声相控阵检测技术在焊缝检测中具有广泛的应用.超声相控阵检测技术检测信号中常混入噪声导致检测成像时难以分辨真实的缺陷特征.这些噪声主要为无关的反射信号和局部相关的结构噪声,传统的超声图像降噪方法难以有效滤除这些噪声,且存在计算效率低、参数优化复杂等问题.该文提出了一种基于深度学习的焊缝超声相控阵检测技术检测S扫图像的降...     

How can automotive friction-induced noises be related to physical mechanisms?

Three main physical mechanisms are found in the literature to explain the occurrence of friction-induced noises: the stick–slip, the sprag-slip and the mode-coupling instabilities. In order to improve the understanding of the automotive friction-induced noises and regarding the variety of these noises and the systems concerned, the consideration of these three physical mechanisms in a unique model, called phenomenological model, is proposed. The relationships between the mechanisms at the origin of friction-induced noises and the different kinds of friction-induced noises that can be perceived in a vehicle are particularly investigated. First, a simple classification of automotive-friction induced noises is proposed and highlights three noise categories: squeal, squeak and creak noises. Time simulations carried out on the phenomenological model show the qualitative reproduction of the vibrational behaviors at the origin of these three noise categories. Conditions are then proposed to define the three noise categories, based on the contact states ratios encountered in the time response. In order to understand the relationships between the three physical mechanisms and the three noise categories, a fullfact design of experiments is carried out with the phenomenological model. A system with realistic dynamic properties is used and submitted to a large number of conditions of use, allowing the appearance of a wide diversity of responses. The results show that the three mechanisms as well as the three noise categories can be obtained on a same dynamic system. They also show that creak is caused by a stick–slip phenomenon, squeal is mainly due to a mode-coupling phenomenon, while squeak can be caused either by mode-coupling or stick–slip phenomena. Finally, the occurrence of each mechanism and noise category is independently analyzed for the given dynamic system, giving quite significant trends towards model parameters. These trends highlight some interesting design levers to reduce the propensity of noise for an automotive structure.     

ICF靶丸装配误差检测

针对激光惯性约束聚变装置中靶丸装配误差检测困难、要求精度高的特点,研制了一套用于微靶装配参数检测的测量系统。提出了一种基于激光与CCD的复合式测量方法,建立了二者数据融合的数学模型,通过标定空间位置关系有效地把二者的测量数据融合到同一个坐标系中,从而实现了高精度三维测量。分两种情况讨论了靶丸装配误差的检测方法。实验结果验证了这两种方法的可行性,并比较了两种方法的测量精度,其极限测量误差均不超过3 m。     

光学元件损伤在线检测中的图像处理

 利用在传统的边缘提取方法上加入灰度抑制,并在梯度计算中考虑每个像素与周围8个邻域的关系的图像处理方法,解决了在线检测中被检测元件以布儒斯特角放置、元件片数较多、CCD所采集的损伤图像噪声成分复杂等造成的像质较差的图像处理问题,并系统地进行了光学元件疵点分析和计算。分析计算结果表明:此图像处理方法得到的损伤疵点尺寸与实际尺寸相符,误差在检测的范围内;为大型光学系统中光学元件损伤的在线、自动化检测提供了一种有用的技术途径。     

Application of structured lighting sensor for online measurement

On the background of increasing request for stringent quality improvement and rising productivity, requirements for online measurement systems are growing as well. Among all the measurement tools, the vision system is considered as the most appropriate tool to provide proper accuracy, high speed, low cost, and 100% online inspection. Structure lighting sensor is the most popular method used in vision system. In this paper, the theory of vision system based on structure lighting is introduced. The measurement application to the seamless steel tube is introduced particularly. Another typical application, the online measurement on car body using structure lighting, is also illustrated.     

Laser-based ultrasonic inspection with a fiber-coupled scanning Cassegrain system

State-of-the-art integrally stiffened composite materials, manufactured for use in the next generation of commercial and military aircraft, are increasingly being used for structural components such as wings and fuselages. However, the complexity of the manufacturing processes can produce small variations in the shape of integrally stiffened composite structures. Thus, a priori knowledge of the nominal part shape often does not provide sufficient accuracy to allow an automated conventional ultrasonic inspection. In contrast, automated inspections of integrally stiffened structures can be performed using laser-based ultrasound techniques since a priori knowledge of the nominal part shape is adequate to scan the laser beams over the structure. This paper addresses the issues associated with the extension of laser-based ultrasonics to inspections in remote and limited access areas, and describes the implementation of a fiber-based remote and limited access LBU inspection system based upon a Cassegrain scanning and optical collection system. The ability to quickly and directly manipulate flexible low mass optical fibers equipped with specialized endoscopic scanning optics make fiber systems an attractive method for the development of limited and remote access inspection systems. The Cassegrain optical system is described in detail and both numerical and experimental validation of the system operational characteristics are presented.     

基于深度学习的太赫兹时域光谱识别研究

太赫兹时域光谱技术,由于其具有物质"指纹谱"特性,是一种可以快速无损地鉴别物质的重要手段,在毒品和爆炸物的无损检测等方面有广阔的应用前景.其中,光谱识别是太赫兹时域光谱技术应用研究的重要方向之一.现有的光谱识别方法多是依靠手工选取特征后进行机器学习分类,或是通过设置吸收峰阈值门限进行判断.由于一些物质在太赫兹波段内并没...     

Procedure for determining manufacturing defects in a diesel engine in a workshop

Customers’ demands regarding the quality level of automobile vehicles are constantly increasing. These demands include noise, vibration and harshness (NVH) quality as an important item.The main source of NVH in the vehicle is the engine and this is particularly the case for diesel engines. The design effort to reduce the emissions of noise and vibration transmitted to the vehicle’s driver could be lessened because of the assembly process variation and assembly errors.In the present paper, a procedure for assessing these variations or errors is suggested in order to maintain NVH performances within the limits of the design and achieve the quality level expected by customers.In order to achieve it, the measurement of the engine vibration level through three sensors allocated at strategic points is suggested. Some objective criteria based on the vibration level at certain frequencies are established to determine possible assembly defects as a final step of the assembly process.     

Numerical study of one-dimensional incommensurate charge-density-wave in the weak pinning regime

By the joint use of the Monte Carlo and molecular dynamics techniques, we show, that a classical treatment of the Fukuyama-Lee model on ID incommensurate CDW in the weak pinning regime can well reproduce many peculiar transport properties attributed to a motion of CDW, such as the nonlinear electric conduction associated with narrow band noises. The results of the inspection of phase profiles in motion are also discussed and the importance of the CDW internal degrees of freedom is demonstrated.     

An Improved Method for Site‐Specific End Modification of Zeolite L for the Formation of Zeolite L and Gold Nanoparticle Self‐Assembled Structures

The ability to site‐selectively modify micro‐ and nanosized particles has allowed for directed self‐assembly in two and three dimensions. Site‐selective modification of particles can be a complicated task requiring the pre‐organization of particles or enhanced particle fabrication methods. The aluminum silicate, zeolite L has been reported to undergo site‐specific modification at the zeolite channel entrances, post‐fabrication in a solution‐based method. The process by which the channel entrances are site selectively modified is explored here. The preliminary step of charging the zeolite channels with aqueous acid allows for catalysis of covalent bond formation at the channel entrances. Three new end‐specific modification reagents are described based on silanol and silyl ether functional groups. These reagents are purified by column chromatography and characterized by¹H NMR spectroscopy and high resolution mass spectrometry (HRMS); they provide for reliable end modification of zeolites L. Preferential reactivity at the channel entrances is also observed. The utility of the approach is demonstrated by modifying zeolite L with adamantane at the channel entrances. Site‐specific self‐assembly with β‐cyclodextrin coated gold nanoparticles can be triggered with a chemical stimulus. The resulting multivalent host‐guest interactions give gold clustered nanoparticles at the ends of the micrometer‐sized zeolites.     

Stochastic bounded consensus tracking of leader-follower multi-agent systems with measurement noises based on sampled data with general sampling delay

In this paper we provide a unified framework for consensus tracking of leader-follower multi-agent systems with measurement noises based on sampled data with a general sampling delay. First, a stochastic bounded consensus tracking protocol based on sampled data with a general sampling delay is presented by employing the delay decomposition technique. Then, necessary and sufficient conditions are derived for guaranteeing leader-follower multi-agent systems with measurement noises and a time-varying reference state to achieve mean square bounded consensus tracking. The obtained results cover no sampling delay, a small sampling delay and a large sampling delay as three special cases. Last, simulations are provided to demonstrate the effectiveness of the theoretical results.     

Z箍缩丝阵参数的视觉检测技术

采用视觉检测技术及图像处理技术相结合的方法,实现了直径约为5μm钨丝丝阵负载单丝的垂直度,相邻两根微丝的间距,丝阵上是否有异物,丝是否断裂等装配参数的自动、连续、无损检测。研究了视觉检测系统图像采集和配置方法,构建了Z箍缩丝阵负载装配参数视觉检测系统。实验结果表明,视觉检测系统的检测精度达2μm,可以精确地检测出丝上异物和丝是否断裂,满足Z箍缩丝阵负载装配参数的检测要求。     

一种快速的图像边缘精确提取算法

图像边缘检测是图像处理与分析中最基础的内容之一。现有的边缘检测算法存在检测精度低、抗噪性能差、处理速度慢等缺点。针对这些问题,提出了一种快速图像边缘检测算法。通过基于图像边缘信息的阈值分割,能快速地提取出图像的边缘轮廓,通过对其进行中心细化,可达到对物体边缘精确定位的目的。仿真实验证明,该算法在滤除图像噪声、保留细节边缘、细化边缘宽度和保持边缘连通性方面都获得了不错的效果,并且运算量小,既适用于对视频图像的实时处理,也适用于对图像中的隐蔽目标特征的提取和分析。     

Effective defect detection in thin film transistor liquid crystal display images using adaptive multi-level defect detection and probability density function

A new automated inspection algorithm is proposed for detecting critical defects based on adaptive multi-level defect detection and probability density function in thin film transistor liquid crystal display (TFT-LCD) images containing a background region’s non-uniform and random noises. To improve the detecting capability for a critical-defect-detecting algorithm, the background region’s non-uniformity is eliminated using statistical values such as the mean and standard deviation of a test image. For the defect detection, the candidate defects are collected on each detection level and used to find a probability density function based on Parzen-window technique. Through simulation it was verified that the proposed method has superior capability for detecting critical defects which results in smaller brightness difference between a defect and its neighbors.     

特种设备信息加密系统设计

对特种设备信息的加密系统进行设计,目前存在信息加密不彻底和采集的可靠性较低等问题。为此,提出特种设备加密系统设计方法,通过信息接口模块完成特种设备中信息的输入和输出,信息流程编辑模块负责开发设备中信息加密流程的组件,完成对特种设备中任务流程的检验,信息流程调度模块对信息流程任务进行调度管理。系统软件设计部分采用数据加密改进方法使信息源节点将要传输的多份信息数据分解成互不相关的信息数据,完成特种设备信息加密系统的设计。实验结果表明,所设计系统信息加密效果好、信息的完备性较高。     

噪声对滑动移除近似熵的影响

受外强迫和仪器本身的测量误差等因素的影响, 观测数据中经常包含噪声和扰动等一些虚假的信息. 针对这一问题, 本文研究了各种不同噪声对滑动移除近似熵的影响. 研究结果表明, 滑动移除近似熵的检测结果受尖峰噪声和高斯白噪声的影响较小, 意味着其具有很强的抗噪能力, 这为该方法在实际观测资料中的广泛应用提供了坚实的实验基础.     

Interferometry with independent Bose-Einstein condensates: parity as an EPR/Bell quantum variable

When independent Bose-Einstein condensates (BEC), described quantum mechanically by Fock (number) states, are sent into interferometers, the measurement of the output port at which the particles are detected provides a binary measurement, with two possible results ±1. With two interferometers and two BEC’s, the parity (product of all results obtained at each interferometer) has all the features of an Einstein-Podolsky-Rosen quantity, with perfect correlations predicted by quantum mechanics when the settings (phase shifts of the interferometers) are the same. When they are different, significant violations of Bell inequalities are obtained. These violations do not tend to zero when the number N of particles increases, and can therefore be obtained with arbitrarily large systems, but a condition is that all particles should be detected. We discuss the general experimental requirements for observing such effects, the necessary detection of all particles in correlation, the role of the pixels of the CCD detectors, and that of the alignments of the interferometers in terms of matching of the wave fronts of the sources in the detection regions. Another scheme involving three interferometers and three BEC’s is discussed; it leads to Greenberger-Horne-Zeilinger (GHZ) sign contradictions, as in the usual GHZ case with three particles, but for an arbitrarily large number of them. Finally, generalizations of the Hardy impossibilities to an arbitrarily large number of particles are introduced. BEC’s provide a large versality for observing violations of local realism in a variety of experimental arrangements.     

Finite Larmor radius magnetohydrodynamic analysis of the ballooning modes in tokamaks

In this paper,the effect of finite Larmor radius (FLR) on high n ballooning modes is studied on the basis of FLR magnetohydrodynamic (FLR-MHD) theory.A linear FLR ballooning mode equation is derived in an ’s α’ type equilibrium of circular-flux-surfaces,which is reduced to the ideal ballooning mode equation when the FLR effect is neglected.The present model reproduces some basic features of FLR effects on ballooning mode obtained previously by kinetic ballooning mode theories.That is,the FLR introduces a real frequency into ballooning mode and has a stabilising effect on ballooning modes (e.g.,in the case of high magnetic shear s ≥ 0.8).In particular,some new properties of FLR effects on ballooning mode are discovered in the present research.Here it is found that in a high magnetic shear region (s ≥ 0.8) the critical pressure gradient (α c,FLR) of ballooning mode is larger than the ideal one (α c,IMHD) and becomes larger and larger with the increase of FLR parameter b 0.However,in a low magnetic shear region,the FLR ballooning mode is more unstable than the ideal one,and the α c,FLR is much lower than the α c,IMHD.Moreover,the present results indicate that there exist some new weaker instabilities near the second stability boundary (obtained from ideal MHD theory),which means that the second stable region becomes narrow.