腔长失调对光腔衰荡法测量精度的影响

 只考虑腔长失调因素下建立了反射率模拟测量的理论模型。根据高斯光束传输规律分析了腔长失调对衰荡腔模式耦合的影响，推导了腔长失调与谐振腔输出脉冲信号、衰荡信号与反射率之间的关系，模拟了腔长失调在±10mm范围内的光脉冲衰荡现象。结果表明：对于光敏面直径为0.2mm的高速探测器，为了保证10^-6的测量精度，腔长的失调量应控制在±1mm之间。在光路调节中采用具有对数变换功能的示波器和动态范围较大的探测器，可以提高测量精度。     

Spectral analysis of the flow sound interaction at a bias flow liner

The interaction between the flow field and the sound field is responsible for the sound absorption at perforated acoustic liners with bias flow and has to be investigated contactlessly. Based on the optically measured flow velocity spectrum, an energy analysis was performed. As a result, the generation of broadband flow velocity fluctuations in the shear layer surrounding the bias flow caused by the flow sound interaction has been observed. In addition, the magnitude of this acoustically induced flow velocity oscillation exhibits a correlation with the acoustic dissipation coefficient of the bias flow liner. This supports the assumption that an energy transfer between the flow field and the sound field is responsible for the acoustic damping.     

一种不同地面分辨率图像的拼接算法

航空遥感监测中变焦镜头的广泛应用以及飞行高度的变化会获得不同地面分辨率的航空影像,因此为了实时监控到飞行区域的整体情况,需要对不同地面分辨率的图像进行拼接。提出了针对不同地面分辨率图像进行拼接的方法。首先用四分法对图像进行分割,检测变化倍率,选择配准策略;然后用基于加速鲁棒性特征(Speeded-Up Robust Features,SURF)的算法对相邻图像进行拼接。获得了焦距变化从高倍过渡到低倍,或从低倍过渡到高倍的拼接图像。通过航空变焦模拟影像的拼接实验和地面变焦影像的拼接实验表明,该方法能够对不同地面分辨率的图像进行拼接,且拼接结果均以高分辨率为基准。     

Non‐contact evaluation of the electrical conductivity of thin metallic films by eddy current microscopy

An eddy current microscopy technique to evaluate the electrical conductivity of thin metallic films in a non‐contact manner is reported. A narrow track formed in an approximately 100 nm thick Au film was prepared, and a Co–Cr coated magnetic tip was driven to oscillate above the track both with and without current passing through the track. Despite the absence of current, the electromagnetic interaction between the tip and the stray magnetic field from the track gave rise to a phase delay in the probe. This was due to an eddy current being induced within part of the track. Moreover, measurements of the phase change in the probe oscillation for different metallic films with thicknesses of about 100 nm found this to be proportional to the electrical conductivity of the film. Finally, the electrical conductivity of an Al film was evaluated using the eddy current microscopy technique. Copyright © 2012 John Wiley & Sons, Ltd.     

1-D zigzag double-chain coordination polymers of transition metals derived from pyridine-2,3,5,6-tetracarboxylic acid

Three new 1-D zigzag coordination polymers {[M₂(pdtc)(bpy)₂(H₂O)₃]?·?4H₂O} _n [M?=?Zn (1), Ni (2), Co (3)] (H₄pdtc?=?pyridine-2,3,5,6-tetracarboxylic acid, bpy?=?2,2′-bipyridine) have been synthesized by the reactions of H₄pdtc and corresponding metal salts in the presence of bpy at room temperature and characterized by elemental analyses, IR, TGA, fluorescence, and X-ray diffraction. The main structural feature of 1–3 is the presence of octahedrally coordinated M1(II) and M2(II) centers sequentially bridged by pdtc ligands; bpy acts as a blocking ligand to avoid further polymerization. These coordination modes lead to 1-D double-chain structures. The 2-D or 3-D supramolecular structures of 1–3 are built up by π?···?π and hydrogen-bond interactions. Two (H₂O)₃ clusters are observed in 1–3. The zinc complex shows strong fluorescent emission at 325?nm.     

蒸发器支撑板板孔精密测量系统

建立了蒸发器支撑板板孔精密测量系统,并提出了基于边缘约束条件的轮廓参量测量方法.首先采用图像处理技术将待测目标转化为二维离散坐标点,计算其最小外接矩形并对轮廓进行预定位;然后将轮廓分割成相互重合的"扩展邻域轮廓",建立以曲率角为原则的边缘约束算法对各轮廓段精确定界,实现对轮廓参量的精密测量.实验和误差分析表明,该系统测量准确度优于0.02mm,对具有复杂轮廓的零件参量测量有参考价值.     

Microstructural and mechanical analysis of Cu and Au interconnect on various bond pads

Effects of High Temperature Storage (HTS) and bonding toward microstructure change of intermetallic compound (IMC) at the wire bonding interface of 3 types of bond pad (Al, AlSiCu and NiPdAu) were presented in this paper. Optical and electron microscope analyses revealed that the IMC growth rate of samples under 175 and 200 °C HTS increased in the order of Al > AlSiCu > NiPdAu. Besides, higher HTS and bonding temperatures also promoted higher IMC thickness. The compositional study showed that higher HTS and bonding temperature developed rapid interdiffusion in bonding interface. In the mechanical ball shear test, a decrease of the shear force of Al and AlSiCu bond pads after 500 h HTS was believed due to poorly developed IMC at bonding interface. On the other hand, shear force degradation at 1000 h was due to excessive growth of IMC that in turn causes the formation of defects. For NiPdAu bond pad, increasing trend of shear force with HTS duration at 175 °C implied a good reliability of the Cu wire bonding. The rapid microscopic inspection on Cu wired Al bond pad under HTS 175 °C showed the IMC development from the periphery to the center of the ball bond. However, after 500 h voids started to develop until the crack was observed at 1000 h.     

Research on the optical fiber gas flowmeters based on intermodal interference

In this work, a self-heating type optical fiber flowmeter with high sensitivity was proposed. The core-offset fiber structures were employed to couple a part of signal light into the fiber cladding layer, and the other part of light still propagated in the core layer. The intermodal interference between the two parts of light happened when the cladding modes were coupled back into core layer. Meanwhile, the high power laser was also introduced into fiber to heat the silver film coated on the surface of the cladding layer. When the cool gas flow passed, the temperature of the sensor probe decreased due to the heat transfer process. Because of the thermo-optic effect in the fiber, interference spectrum could be shifted when the temperature was changed. The experimental results showed the resolution of the proposed sensor was 2×10⁻² m/s in the region of 0–8 m/s. The highest sensitivity could achieve 1537 pm/(m/s).     

Development of Optical Techniques for Chemical Engineering Applications

The design of separation processes for nuclear spend fuel treatment, dedicated to either R&D studies or industrial applications, is currently based on a phenomenological approach, relying on Computational Fluid Dynamics, and complemented by validation tests achieved at small-scale. Indeed, most of the steps of the PUREX^® process involve multiphasic flows (dissolution, leaching, liquid-liquid extraction, precipitation, filtration, etc.). Therefore an accurate knowledge of the dispersed phase properties is required in order to assess their coupling with the flow features, to predict the process performance and efficiency and to achieve size reduction or extrapolation.Hence, the measurements of particulate flows properties, and especially the particles (or drops or bubbles) size distribution, concentration (i.e. hold-up) and velocity has become a growing issue. Relevant techniques for measuring these flow properties are multiple, from the high-speed video acquisition coupled to image processing to the laser-induced fluorescence, including the particle imaging velocimetry or interferometric techniques (digital in-line holography, rainbow refractometry, etc.). In this communication, different techniques developed at CEA Marcoule for the characterization of multiphase flows, will be introduced. The strong interaction with computational fluid dynamics, in the scope of a multiscale approach, will be discussed through typical results of gas-liquid, liquid-liquid and solid-liquid flows possibly encountered in nuclear fuel reprocessing process.