Synthesis and optical properties of MgO-doped ZnO microtubes using microwave heating

The Zn_1−xMg_xO (x = 0%, 2% and 5%) microtubes have been successfully synthesized via a microwave heating method. The as synthesized microtubes were carefully investigated. Field emission scanning electron microscope (FE-SEM) showed that all the microtubes exhibit an exact hexagonal hollow structure with smooth surfaces and straight characteristics throughout their whole lengths. UV–Vis measurement indicates that the absorption peak for ZnO microtube was shifted from 378.88 nm (3.27 eV) to 369.91 nm (3.35 eV) for Zn_0.95Mg_0.05O microtube. Room temperature photoluminescence (PL) spectra showed that the intensity of UV emission peak decreased with increase of MgO concentration and the visible emission band showed a blue shift from 538.06812 nm for ZnO microtube to 529.54114 nm for Zn_0.95Mg_0.05O microtube. Energy-dispersive spectrometer (EDS) analysis revealed the presence of Zn and O as the only elementary components with the absence of MgO as a doping material.     

Design and fabrication of an alternating dielectric multi-layer device for surface plasmon resonance sensor

An alternating dielectric multi-layer device was fabricated and tested in the laboratory to show that dielectric mirrors of alternating high/low refractive index materials, based on the design of distributed Bragg reflector (DBR) for vertical cavity surface emission lasers (VCSELs), can be used in designing SPR biochemical sensors. The thickness, number of layers, and other design parameters of the device used were optimized using optical admittance loci analysis. The proof-of-concept device was fabricated with a symmetrical structure using Au/(SiO₂/TiO₂)₄/Au.Using a 632 nm-wavelength light source on a BK7 coupling prism, our laboratory tests showed that, under water, there was an 11.5° shift in resonant peak position towards the critical angle (from 74° in a conventional single-layer Au film), and a 3.25 times decrease in FWHM (the half-peak width). Our design also resulted in a wider dynamic range of up to a 1.50 refractive index unit (RIU), compared to 1.38 RIU in a conventional single-layer Au film. Using glucose solutions in ddH₂O, the calculated resolution was 1.28 × 10⁻⁵. The calculated intensity sensitivity was 10 000 a.u./RIU, about twice the improvement over the conventional single-layer Au film.     

Analysis of the importance of structural change in non-energy intensive industry for prospective modelling: The French case

A large number of studies have been conducted on the contribution of technological progress and structural change to the evolution of aggregate energy intensity in the industrial sector. However, no analyses have been done to examine theses changes in the non-energy intensive industry in France. We analyzed their importance in French industry with respect to their energy intensity, energy costs, value added, labour and the diffusion of production sites by using data at the 3-digit level with 236 sectors. Using a new decomposition method that gives no residual, this paper attempted to examine, over 10 years from 1996 to 2005, the changes that occurred in an area that has been neglected in energy analysis. We found that structural change had an overwhelming effect on the decline of aggregate energy intensity. Furthermore, we found that the higher the level of sector disaggregation, the more significant the changes that can be attributed to structural change, due to the homogeneity of this industrial group. The results of our study show that it is important to take into account the effects of structural change in “bottom-up” modelling exercises so as to improve the accuracy of energy demand forecasting for policy-makers and scientists.     

基于隐式空间映射算法微波滤波器的优化设计

该文叙述了隐式空间映射算法的方法,并应用隐式空间映射法优化设计了中心频率为5.5 GHz,通带带宽为800MHz的超宽带微波平行耦合谐振滤波器.滤波器经过3次的迭代达到了设计指标,减少了在精确模型中的仿真次数,与通常电磁仿真软件的参数扫描相比优化效果明显.     

Physical conditions for sources radiating a cosh-Gaussian model beam

Based on the coherence theory of diffracted optical field and the model for partially coherent beams,analytical expressions for the cross-spectral density and the irradiance spectral density in the far zone are derived,respectively.Utilizing the theoretical model of radiation from secondary planar sources,the physical conditions for sources generating a cosh-Gaussian(CHG) beam are investigated.Analytical results demonstrate that the parametric conditions strongly depend on the coherence property of sources.When almost coherence property is satisfied in the source plane,the conditions are the same as those for fundamental Gaussian beams;when partial coherence or almost incoherence property is satisfied in the spatial source plane,the conditions are the same as those for Gaussian-Schell model beams.The results also indicate that the variance of cosine parameters has no influence on the conditions.Our results may provide potential applications for some investigations such as the modulations of cosh-Gaussian beams and the designs of source beam parameters.