Long-wavelength stability of an unsupported multilayer liquid film falling under gravity

The long-wavelength stability of an unsupported multilayer liquid film falling under the effects of gravity and surface tension is investigated. By considering the Navier–Stokes equations for two fluid layers in the high-Reynolds-number and small-aspect-ratio limits the steady-state solutions are obtained. The stability criterion found by Lin (J Fluid Mech 104:111–118, 1981) for a one-layer fluid curtain is generalised to the two-layer case and the criterion for an n-layer curtain is established.     

Shear banding deformation in Cu/Ta nano-multilayers

Nanoscale Cu/Ta multilayers with individual layer thickness ranging from 3 to 70 nm were deformed under nanoindentation at room temperature. Shear bands can be observed only when individual layer thickness is reduced to 9 nm or below, indicating formation of shear bands in the Cu/Ta multilayers is layer thickness dependent. By observing the cross sectional transmission electron microscope images of the indentation fabricated through focused ion beam technique, shear banding deformation causing a unique layer-morphology with prevalent mismatched laminate structure has been reported for the first time. By capturing and analyzing a series of typical indentation-induced deformed microstructures, a new physical mechanism of shear banding behavior in metallic nano-multilayers is suggested.     

诱导透射滤光片的研制

本文介绍了诱导透射滤光片的设计原理,给出了膜系设计和实验结果,并对有关工艺进行了讨论。     

A study of photoconductive properties of vacuum-sublimated copper-phthalocyanine/zinc sulphide multilayer films

Copper-phthalocyanine (CuPc)/zinc sulphide (ZnS) multilayer films were prepared by vacuum-sublimation. X-ray diffraction, optical absorption spectra and photoconductive properties were measured for the multilayer films. The results showed that the photoconductive properties of the CuPc/ZnS multilayer films were better than that of the CuPc film. The effects of the pair number on the photoconductive properties of the multilayer films were studied. It was found that three-pair CuPc/ZnS multilayer film had the best photoconductive properties with the light sensitivity S=100 lx s and residual potential V_R=17 V.     

Rolling textures in nanoscale Cu/Nb multilayers

Rolling textures in nanoscale multilayered thin films are found to differ markedly from textures observed in bulk materials. Multilayered thin films consisting of alternating Cu and Nb layers with columnar grains were produced by magnetron sputtering, with individual layer thickness ranging from 4 μm to 75 nm and Cu/Nb interfaces locally satisfying the Kurdjumov–Sachs (K–S) orientation relations. After rolling to 80% effective strain, samples with a larger initial layer thickness develop a bulk rolling texture while those with a smaller initial layer thickness display co-rotation of Cu and Nb columnar grains about the interface normal, in order to preserve the K–S orientation relations. The resulting K–S texture has 0 0 1Nb parallel to and 1 1 0Cu approximately 5° from the rolling direction. A crystal plasticity model based on the Principle of Minimum Shear captures the K–S texture approximately and suggests that Nb drags Cu along in the rotation process.     

An MLP-based texture segmentation method without selecting a feature set

A texture segmentation technique which employs a multilayer perceptron (MLP) and does not consider the selection of features is presented in this paper. Thus, users can avoid selection and computation of the feature set and hence real-time segmentation may be possible. The technique apparently works in a fashion similar to our visual system whereby we do not consciously compute any feature for texture discrimination. A detailed study has been made for the selection of the network size. A newly proposed variant of the back-propagation algorithm has been used for more efficient training of the network. An edge-preserving noise-smoothing approach has been proposed to remove noise from the segmented image.     

多层各向异性地基的初参数解法

本文推导了多层各向异性地基在轴对称表面荷载作用下的位移和应力的初参数解法。所用的方法是Fourier-Bessel积分变换和矩阵递推法。并已将多层各向异性地基的位移和应力的一般表达式编制了计算程序,通过算例验证了该方法的精确性和实用性。     

Ultrafast synthesis of Au(I)-dodecanethiolate nanotubes for advanced Hg2+ sensor electrodes

In this work, an ultrafast and facile method is developed to synthesize Au(I)-dodecanethiolate nanotubes (Au(I)NTs) with the assistance of glycyl-glycyl-glycine (G-G-G). Transmission electron microscopy (TEM) images reveal that the as-prepared Au(I)NTs can be obtained in a 2-h reaction instead of a previous 24-h reaction and are uniform with a hollow structure and smooth surface by virtue of the G-G-G peptide tubular template. According to structural analysis, a possible preparative mechanism is proposed that the G-G-G peptide could help to curl into tube-like morphology in alkaline situation spontaneously to accelerate the formation of Au(I)NTs. Meanwhile, PVDF-stabilized Au(I)NT-modified glassy carbon electrodes present their promising potential for Hg²⁺ detection.     

Solar absorption behaviour of multilayer stacks

In this paper, the absorption spectra of multilayer structures have been obtained and analysed in the wavelength range 0.5–10 μm. The multilayer system is an SMS type in which M is a thin metallic layer sandwiched between two semiconducting layers. The systems (i) B.S./Cu/B.S. and (ii) Cu₂S/Cu/Cu₂S (where B.S. = black sulphide) are developed by the methods of electrodeposition/chemical dipping, whereas the ZnS/Cu/ZnS system is fabricated in vacuo. The /ε ratios are also calculated using the experimentally observed absorption spectra, and found to be higher in the case of the ZnS/Cu/ZnS system, in comparison to the other two systems. The absorption spectra have also been calculated using our theoretical model of the above-mentioned systems.     

Novel multilayer Nafion/SPI/Nafion composite membrane for PEMFCs

A novel multilayer membrane for the proton exchange membrane fuel cell (PEMFC) was developed. Nafion was dispersed uniformly onto both sides of the sulfonated polyimide (SPI) membrane. The Nafion/SPI/Nafion composite membrane was prepared by immersing the SPI into the Nafion-containing casting solution. Through immersing both membranes into the Fenton solution at 80 °C for 0.5 h for an accelerated ex situ test, chromatographic analysis of the water evacuated from the cathode and the anode of the cells and a durability test of a single proton exchange membrane fuel cells, it was proved that the stability of the composite membrane has been greatly improved by adding the Nafion layer compared with the SPI membrane. The fuel cell performance with the SPI and Nafion/SPI/Nafion membranes was similar to the performance with the commercial product Nafion^® NRE-212 membrane at 80 °C.