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In this work, low pressure glow discharge O2 plasma has been used to increase wettability in a LDPE film in order to improve adhesion properties and make it useful for technical applications. Surface energy values have been estimated using contact angle measurements for different exposure times and different test liquids. In addition, plasma-treated samples have been subjected to an aging process to determine the durability of the plasma treatment. Characterization of the surface changes due to the plasma treatment has been carried out by means of Fourier transformed infrared spectroscopy (FTIR) to determine the presence of polar species such as carbonyl, carboxyl and hydroxyl groups. In addition to this, atomic force microscopy (AFM) analysis has been used to evaluate changes in surface morphology and roughness. Furthermore, and considering the semicrystalline nature of the LDPE film, a calorimetric study using differential scanning calorimetry (DSC) has been carried out to determine changes in crystallinity and degradation temperatures induced by the plasma treatment. The results show that low pressure O2 plasma improves wettability in LDPE films and no significant changes can be observed at longer exposure times. Nevertheless, we can observe that short exposure times to low pressure O2 plasma promote the formation of some polar species on the exposed surface and longer exposure times cause slight abrasion on LDPE films as observed by the little increase in surface roughness. 相似文献
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M. A. Sanchis 《Zeitschrift fur Physik C Particles and Fields》1991,52(3):511-515
Flavor-changing effective verticesq
l
q
h
V
0, whereV
0 represents a neutral gauge boson (,Z
0,g), involving a heavy external quark, are discussed within the standard model at one-loop level and second-order approximation in external momenta and masses: the logarithmic singular terms in the form factors at vanishing mass of the internal quark in the loop have to be replaced by pieces coming from next order in external momenta. Implications in thebd+X penguin transitions are commented. 相似文献
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A simple theoretical model of a Mach-Zehnder interferometer (MZI) consisting of two coupled-resonator optical waveguides with different lengths is proposed and experimentally demonstrated at microwave frequencies. Good agreement between theoretical and experimental results is observed. MZIs in planar photonic crystals may become key building blocks in the development of microscale optical integrated devices such as filters, demultiplexers, switches, and modulators. 相似文献
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Photonic crystal technology allows the creation of optical waveguides with low sharp-bending losses as well as ultra-low group velocity. This last property is particularly interesting to develop highly-compact optical devices based on the controlled modification of the optical phase of the signals traveling through the waveguides. Among these devices, the Mach–Zehnder interferometer acquires fundamental importance because it can be used as a building block of more complex optical devices and functionalities such as optical filters, wavelength demultiplexers, channels interleavers, intensity modulators, switches and optical gates. In this paper, the performance of a Mach–Zehnder interferometer consisting of two coupled-cavity waveguides with different lengths created in a two-dimensional photonic crystal is theoretically analyzed. We also provide simulation results using a finite-difference time-domain code that confirm the theoretical analysis. The main limitations in the performance of the structure are addressed and discussed. 相似文献
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