Optical characterization of photochromic effect

Photochromic powders are powders whose color is sensitive to UV irradiation. When such a powder is exposed to the sunlight or any other UV rays, it becomes darker and then looks back progressively to its initial color. An optical method has been set up in order to quantify these colors variations. We can then quantify the variations in the colorimetric space, and the time response of the coming back phenomenon.     

Scattering loss in Nd-doped silica based optical fibers

Rare-earth doped fibers suffer from relatively high attenuation in comparison to conventional communication fibers. In order to improve the properties of such fibers, understanding of the mechanisms involved in scattering effects is of great importance. The effect of Nd-doping, Al-codoping and of the drawing temperature on the scattering effect was investigated for several different optical fibers. To this end a measuring setup was realized which allows absolute measurements of the scattering coefficient at different positions along a fiber. Also separation of total attenuation and scattering effects is possible. The presented results indicate scattering effects as primary source for increased attenuation compared with undoped fibers.     

Magneto-optical visualization of a sound-induced domain structure in hematite

Non-uniform spin states (stripe domains) are induced by powerful pulse ultrasonic waves in a hematite (-Fe₂O₃) single crystal. These states are visualized with the help of the Cotton-Mouton effect and quantitatively described in terms of an effective field proportional to the square of ultrasound amplitude.     

Phase diagram for stripes in YBa2Cu3O6+x superconductors

Neutron scattering has been used to measure the charge and spin structure in the YBa₂Cu₃O_6+x superconductors. Incommensurate static charge ordering is found at low doping levels while only charge fluctuations are found at higher doping. The spin structure is complex with both a commensurate resonance and incommensurate structure observed at low temperatures. The scattering results are used to construct a phase diagram for stripes in the YBa₂Cu₃O_6+x system.     

THE THREE-DIMENSIONAL STRESS INTENSITY FACTOR UNDER MOVING LOADS ON THE CRACK FACES

The dynamic stress intensity factor history for a half plane crack in anotherwise unbounded elastic body,with the crack faces subjected to a tractiondistribution consisting of two pairs of combined mode point loads that move in adirection perpendicular to the crack edge is considered.The analytic expression for thecombined mode stress intensity factors as a function of time for any point along thecrack edge is obtained.The method of solution is based on the application of integraltransform together with the Wiener-Hopf technique and the Cagniard-de Hoop method.Some features of the solution are discussed and graphical results for various point loadspeeds are presented.     

Method of Self-Mixing in the Spectroscopy of Quasielastically Scattered Laser Radiation

Interaction of a semiconductor laser with its self-radiation quasielastically scattered in the environment is considered. It is established that at small coefficients of coupling of the laser with the scattering medium the spectral density of the power of an optoelectronic signal in the laser faithfully reproduces the shape of the scattered-radiation spectrum at the Doppler-shift frequencies. This makes it possible to measure the spectrum with a resolution characteristic for optical homodynation by recording the optoelectronic signal.     

A NEW ENGINEERING CALCULATING MODEL FOR A LINEAR INCLUSION AND ITS APPLICATIONS

By using the hypothesis of the deformation of the straight bar and beamin mechanics of materials,a new engineering calculating model for a linear inclusion inplane is presented.Through the Kelvin's solution of a concentrated force,the inclusionproblem is reduced to solving a set of uncoupled singular integral equations which canbe solved by the numerical method of singular integral equation.Based on theseresults,several applicable examples including an inclusion-crack problem are calculatedand the results are quite satisfactory.     

一种软X射线多层膜界面粗糙度的计算方法

提出一个利用多层膜小角X射线衍射谱衍射峰积分强度计算多层膜界面粗糙度的公式。用磁控溅射技术制备Mo／Si多层膜，用波长为0．154nm的硬X射线测量样品在小掠入射角区的衍射曲线，分别用本文公式和反射率曲线拟合方法计算了样品的界面粗糙度。实验结果表明：由本文公式获得的界面粗糙度近似于拟合方法获得的界面粗糙度，它们略等于多层膜界面实际粗糙度。     

Resonance light scattering technique used for biochemical and pharmaceutical analysis

By coupling and scanning simultaneously excitation and the emission monochromators of a common spectrofluorometer, enhanced resonance light scattering (RLS) signals could be obtained. The enhanced RLS signals could be used for designating bio-assemblies, aggregation species, and analytical purposes. Herein, we review the reports since the year of 2000 concerning the biochemical and pharmaceutical analysis with the RLS measurements, and discuss the possible developments of this technique.     

拉曼对光散射的实验研究

介绍了拉曼的生平和对物理学的主要贡献，回顾了他从观察海水的蓝色人手，继而发现气体、液体对光的散射规律，一直到发现物质的散射光不仅包含原来的波长，而且还包括与原入射光不同的其他波长的散射的研究过程，并讨论了他的成功对我们的启示．