Nanocrystallization of the amorphous Co-B-Si alloys formed by melt spinning and mechanical alloying

X-ray diffraction, differential scanning calorimetry, and transmission electron microscopy were used to investigate the thermal stability and peculiarities of nanocrystallization upon heating of amorphous Co_65.5S₁₈B₁₀ M _6.5 (M = Cr, Fe) alloys obtained by melt-spinning (MS) and mechanical alloying (MA) of mixtures of elemental components. It is shown that, irrespective of the method of manufacture, the amorphous iron-containing alloys, in general, have a lower thermal stability than the chromium-containg alloys. The thermal stability of MA alloys is lower than that of the MS alloys of the same chemical composition. The processes of nanocrystallization during heating of MS and MA amorphous alloys differ. The first crystallize, when heating, through the formation of intermediate phases, and the second, with the formation of stable crystalline phases directly from the amorphous matrix. After the crystallization, the alloys have a nanocrystalline structure with a crystallite size of about 20 nm and the same phase composition of crystallization products for the alloys of the same nominal composition obtained by MA and MS: ɛ-Co, Co₂B, and β-Co₂Si for Co_65.5Si₁₈B₁₀Cr_6.5 and α-Co, Co₂B, β-Co₂Si, and (Fe,Co)₃Si for Co_65.5Si₁₈B₁₀Fe_6.5. The results are discussed in terms of the excess free volume of the amorphous phase and of the value of its specific surface area.     

Single-particle evanescent light scattering simulations for total internal reflection microscopy

We simulate and measure light scattering of a micrometer-sized spherical particle suspended in solution close to a glass substrate. The model, based on the discrete sources method, is developed to describe the experimental situation of total internal reflection microscopy experiments; i.e., the particle is illuminated by an evanescent light field originating from the glass-solvent interface. In contrast to the well-established assumption of a simple exponential decay of the scattering intensity with distance, we demonstrate significant deviations for a certain range of penetration depths and polarization states of the incident light.     

严格按照中央要求继续推进节能减排工作——对吴江市印染行业近几年节能减排工作的调查

吴江市印染行业是耗能、排污大户,在当前创建资源节约型、环境友好型社会的热潮中首当其冲。吴江市丝绸协会曾于2003年6月对该行业的节能减排工作做过调研,近几年在这方面有哪些建树?根据中央对节能减排的更高要求,下一步棋应该怎么走?这是摆在大家面前的重要课题。为此,协会近期又作了调研。