体相位全息光栅式波分复用器的研究

利用体相位全息光栅的优良特性,研制光栅式密集型波分复用器(DWDM)。准直后的信道波长通过体相位全息光栅两次衍射,在焦面上实现信道波长的分复用。阐述了体相位全息光栅的独特结构特点,给出了体相位全息光栅式密集型光波分复用器件的原理图,计算出各个信道的位置及间隔,用Zemax仿真出设计模型。相比于薄膜滤光片式器件而言,具有许多独特的优良特性,能够实现更密集更多信道数量的分复用。     

Energy balance in dense microemulsions

A water-in-oil microemulsion composed of water, AOT and decane with volume fraction φ=0.50 and molar ratio X=40.8 was analysed by DSC. The percolation and the bicontinuous transitions as well as the melting endotherms and the freezing exotherms were measured. The main attention was focussed on the system energy balance. It was found that, by freezing the samples after the occurrence of the percolative transition, the total heat released is significantly less than the heat absorbed in the melting endotherms. A simple geometrical model was used as an analysis tool of the aforementioned energy difference. Since the system studied exhibits a percolative transition of dynamic type, on approaching the percolation threshold temperature (T≤T _p) and a static percolation for T≥T _p, the structural change from the connecting water-droplet-cluster to a connecting water channel was schematised in the model as a change from a sphere-necklace to a water-cylindrical channel of equal volume and equal length. The surface energy associated with the formation of the two different geometrical surfaces was evaluated and the amount of saved energy compared with the experimentally measured one.     

The behaviour of macromolecules in the flow through a sudden planar contraction

Analytic steady-state results for FENE-P model macromolecules, in the nearly coiled-up and nearly stretched state respectively, in general two-dimensional flow fields are derived. These results are utilized in the flow through a sudden planar contraction. Special emphasis is devoted to the structure tensor R R, which furnishes, among other things, the mean square extension and the average orientation of the macromolecules.     

Opacity and radiative power losses calculations

In this contribution we present results on opacity and radiative power losses in laser-produced plasmas. We focus our attention on the inner shell transition array 1s–2p in an aluminum plasma. At high densities, electron, Doppler and ion Stark broadening play a role in line merging. This is why the PPP line-shape code developed at Université de Provence was adapted to calculate opacity and radiative power losses in Al and Ge ions. Atomic physics data required in PPP calculations is provided by an MCDF code. Comparison with experiments is discussed.     

快速床动力学统一模型Ⅱ:上部稀相与下部浓相固含率的预报

在前文建立的分相共存快速床动力学模型的基础上,对分相模型中存在颗粒团聚物时的上升稀相进行了受力分析。以有限直径提升管中颗粒终端速度的修正,导出了上升稀相受力关于等效管径与浓稀相滑移速度的修正表达式。将本模型预报的上部稀相固含率与已有的实验数据经验关联式进行了对比,并根据所得结果初步优化了模型参数(k=8,n=6)。进而,根据所得模型参数计算了下部浓相固含率随曳力函数f(ε)的变化规律;与李佑楚经验关联式相比,同样具有合理的一致性。本文工作进一步验证了快速床动力学统一模型的整体合理性。     

Dipolar contrast for dense tissues imaging

A new type of contrast called dipolar contrast is obtained by a decrease in the dipolar line broadening of protons. This contrast is usable for dense tissue NMR imaging and more generally for the study of dipolar linked protons in biological tissues. The sequence used is based on a variant of the Magic Sandwich Echoes (MSE) technique. In vitro experiments on a tendon sample are used to reinforce the image intensity of regions where the direct proton dipolar interaction exists.     

Analysis of visual perception of light emitting diode brightness in dense fog with various droplet sizes

Road signs must provide a conspicuous signal to a wide variety of drivers over a broad range of environmental and geometric conditions. Recently, there are an increasing number of applications in which light emitting diodes (LEDs) are used as the light source, including critical transportation signaling. In the presence of fog, the resulting visual signal is disturbed due to light scattering by airborne water droplets. By measuring LED brightness with human spectral sensitivity in various densities and various droplet sizes (10, 30, 50, and 100 μm), it is understood that the particle size distribution (fog droplet size) and density of fog does affect visibility in fog. The colored LEDs that contain a yellow component had high brightness evaluation, blue component had low brightness evaluation in all densities and different droplet sizes. The result in this paper can contribute to air and land traffic safety and the prevention of accidents.     

超大规模集成电路波导光互连技术的现状与前景

介绍超大规模集成电路(VLSI)波导(?)互连技术的最新进展,并预测其发展方向,以及如阿解决存在的实际问题。     

Closely packed dense frequency selective surface

In order to realize wideband filtering properties of frequency selective surface （FSS）, FSS of closely packed elements is presented. The Y loop elements are chosen as the graphics elements. Based on the spectral domain method, the frequency response is analyzed for different incident angles and polarizations. The result of the numerical analysis shows that the dense FSS has wide passband with better independence of angle and polarization.