Space-selective co-precipitation of silver and gold nanoparticles in femtosecond laser pulses irradiated Ag+, Au3+ co-doped silicate glass

We report on space-selective co-precipitation of silver and gold nanoparticles in Ag+, Au3+ co-doped silicate glasses by irradiation of femtosecond laser pulses and subsequent annealing at high temperatures. The color of the irradiated area in the glass sample changed from yellow to red with the increase of the annealing temperature. The effects of average laser power and annealing temperature on precipitation of the nanoparticles were investigated. A reasonable mechanism was proposed to explain the observed phenomena. (c) 2006 Elsevier Ltd. All rights reserved.

Gizarte erantzukizun eta garapen jasangarriaren inguruko ekimenak: Global Compact

[EU]Gradu Amaierako lan honetan, enpresen gizarte erantzukizunak azkenaldian hartu duen garrantzia kontuan hartuta, kontzeptu hau jorratuko da eta eremu honetan burututako ekimen ezberdinen artean bat aukeratuko da, honen garapena eta inplementazioa aztertzeko. Hain zuzen ere, lan honetan erabiliko den ekimena, Munduko Hitzarmena edo Global Compact-a izango da. Hau, nazioarte mailako ekimen bat izanik, 10 printzipio proposatzen ditu, lau eremu ezberdinetan banatuz: Giza eskubideak, lan-arauak, ingurumena eta ustelkeriaren kontrako borroka. Bukatzeko, Global Compact-a aplikatzen duten sektore ezberdinetako hiru enpresa aukeratuko dira eta bakoitza dimentsio bat aztertzeko erabilia izango da, soziala, ekonomikoa eta ingurumenekoa hurrenez hurren. Azkenik, lanean zehar aztertutakoa kontuan hartuta zein ondoriotara iritsi garen adieraziko da.

Space-selective precipitation of Au nanoparticles inside silica gel

Au colloids were prepared by irradiation with a Nd:YAG laser. Au nanoparticles were characterized by absorption spectra, transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis. It is found that the wavelength of the laser has no effect on the size but the number of the Au nanoparticles. By irradiating a transparent silica gel doped with gold ions with the focused laser in the gel and subsequent exposing in air, a space-selective pattern of letter "P" consisting of Au nanoparticles was observed inside the silica gel.

Growth and spectroscopic characteristics of Yb : LPS single crystal

For the first time, a high optical quality Yb3+-doped lutetium pyrosilicate laser crystal Lu2Si2O7 (LPS) was grown by the Czochralski (Cz) method. The segregation coefficient of ytterbium ion in Yb:LPS crystal detected by the inductively coupled plasma atomic emission spectrometer (TCP-AES) method is equal to 0.847. X-ray powder diffraction result confirms the C2/m phase monoclinic space group of the grown crystal and the peaks corresponding to different phases were indexed. The absorption and fluorescence spectra, as well as fluorescence decay lifetime of Yb3+ ion in LPS have been investigated. The absorption and fluorescence cross-sections of the transitions F-2(7/2) <-> F-2(5/2) of Yb3+ ion in LPS crystal have been determined. The advantages of the Yb:LPS crystal including high crystal quality, quasi-four-level laser operating scheme, high absorption cross-sections (1.33 x 10(-2) cm(2)) and particularly broad emission bandwidth (similar to 62 nm) indicated that the Yb:LPS crystal seemed to be a promising candidate used as compact, efficient thin chip lasers when LD is pumped at 940 and 980 nm due to its low-symmetry monoclinic structure and single crystallographic site. (c) 2007 Elsevier B.V. All rights reserved.