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31.
Preparation and characterization of new fluorotellurite glasses for photonics application 总被引:1,自引:0,他引:1
Guihua Liao Jianjun Xing Hrvoje Gebavi Daniel Milanese Michael Fokine Monica Ferraris 《Journal of Non》2009,355(7):447-503
Glasses based on (85 − x)TeO2-xZnF2-12PbO-3Nb2O5 (x = 0-40) system have been studied for the first time for fabricating mid-infrared optical fiber lasers. The thermal and optical properties including UV-Vis, Raman as well as FTIR spectra are reported. It is demonstrated that increasing the ZnF2 concentration to 30 mol% significantly increased the thermal stability of the glass. Adding ZnF2 also reduced the hydroxyl (OH) content of the glass resulting in lower optical absorption in the mid-infrared region, which is crucial for infrared laser applications. The glass absorption cut-off edge near 400 nm blue-shifts with increasing ZnF2 addition. Raman spectra show a depolymerization of the glass network with increasing transformation of TeO3+1 to TeO3 structures. 相似文献
32.
Daniel Milanese Monica Vota Jianjun Xing Hrvoje Gebavi Nicola Coluccelli 《Journal of Non》2008,354(18):1955-1961
In this paper we describe fabrication and characterization of rare-earth-doped active tellurite glasses to be used as active laser media for fiber lasers emitting in the 2 μm region. The base composition is (mol%): 75TeO2-20ZnO-5Na2O with different concentrations of Tm3+, Yb3+ and Ho3+ as dopants or co-dopants. Optical properties of doped glasses were studied and pumping at 800 nm and at 980 nm were tested in order to compare the efficiency of two pumping mechanisms. Optical characterization carried out on glasses containing only Tm3+ ions indicated the optimum concentration of Tm2O3 in terms of emission efficiency as 1 wt%. The addition of 5 wt% of Yb2O3 to Tm3+-doped glasses led to the best results in terms of intensity of fluorescence emission and of lifetime values. Yb and Ho co-doped Tm-tellurite glass was measured in emission. 相似文献
33.
In an interferometric pump-probe experiment, we demonstrate the phase tuning of the spin polarization of photoelectrons emitted in a three-photon process from Cu(001). A phase shift of pi between delayed ultrafast circularly polarized light pulses can switch the spin polarization from +/-20% to -/+40%. In the delay regime of overlapping pulses, we show the dominating role of optical interference effects in determining the spin polarization. For longer delays, we detect the influence of the coherent material response, manifested in both the final state electron population as well as the final state spin polarization. 相似文献
34.
Optical spatial solitons made from incoherent white light were experimentally observed in 1997 by Mitchell and Segev [Nature (London) 387, 880 (1997)]. We present what is believed to be the first theory describing these solitons and find the characteristic features of their spatiotemporal coherence properties and their temporal power spectrum. 相似文献
35.
Tayebeh Sharifi Marin Kova
i Monika Belec Klara Perovi Marin Popovi Gabrijela Radi Botjan
ener Anamarija Pulitika Marijana Kralji Rokovi Urka Lavren
i
tangar Ana Lon
ari Boi Hrvoje Kui 《Molecules (Basel, Switzerland)》2022,27(22)
Sustainable hydrogen production is one of the main challenges today in the transition to a green and sustainable economy. Photocatalytic hydrogen production is one of the most promising technologies, amongst which BiVO4-based processes are highly attractive due to their suitable band gap for solar-driven processes. However, the performance of BiVO4 alone in this role is often unsatisfactory. Herein we report the improvement of BiVO4 performance with reduced graphene oxide (rGO) as a co-catalyst for the photoelectrochemical water splitting (PEC-WS) in the presence of simple functionalized benzene derivatives (SFBDs), i.e., phenol (PH), benzoic acid (BA), salicylic acid (SA), and 5-aminosalicylic acid (5-ASA) as potential photogenerated hole scavengers from contaminated wastewaters. Linear sweep voltammetry and chronoamperometry, along with electrochemical impedance spectroscopy were utilized to elucidate PEC-WS performance under illumination. rGO has remarkably improved the performance of BiVO4 in this role by decreasing photogenerated charge recombination. In addition, 5-ASA greatly improved current densities. After 120 min under LED illumination, 0.53 μmol of H2 was produced. The type and concentration of SFBDs can have significant and at times opposite effects on the PEC-WS performance of both BiVO4 and rGO-BiVO4. 相似文献
36.
Hrvoje Hrgovčić 《International Journal of Theoretical Physics》1994,33(4):745-795
A simple model of many-body quantum mechanics governed by completely local interactions in ordinary three-dimensional space is presented. The equations of motion, involving no Euclideanization of time, are elementary extensions of those describing random walks on a square lattice, and are far simpler than those obtained through standard path-integral theory. A quantity is defined in terms of populations of particles on the lattice, whose expectation value is proportional to the square of the multiparticle wave functions associated with the system; for sufficiently microscopic measurement scales, this generalized density may take on negative values, thereby circumventing the constraints imposed by Bell's inequality. 相似文献
37.
Jelena Macan Ivan Brnardi? Sebastijan Orli? Hrvoje Ivankovi? Marica Ivankovi? 《Polymer Degradation and Stability》2006,91(1):122-127
Degradation kinetics of organic-inorganic hybrid materials based on epoxy resin were investigated by thermogravimetric analysis (TGA). The hybrid materials were prepared from diglycidyl ether of bisphenol A (DGEBA) and 3-glycidyloxypropyltrimethoxysilane (GLYMO) polymerised simultaneously by poly(oxypropylene)diamine (Jeffamine D230). Nanometric level of homogeneity in the hybrids was verified by electron microscopy. Energy of activation of degradation for the hybrids with varying inorganic content, as well as for the unmodified epoxy-amine system, was determined by the isoconversional Kissinger-Akahira-Sunose method, and was found to be significantly higher for the hybrid materials than for the unmodified epoxy-amine system. The degradation process was described by empirical kinetic models. The results indicated that presence of the inorganic network influences the mechanism of degradation of organic phase. Greater thermal stability of hybrid materials was confirmed by other parameters obtained from TGA curves. 相似文献
38.
Light-triggered polymerase chain reaction 总被引:2,自引:0,他引:2
Young DD Edwards WF Lusic H Lively MO Deiters A 《Chemical communications (Cambridge, England)》2008,(4):462-464
Photochemical control of the polymerase chain reaction has been achieved through the incorporation of light-triggered nucleotides into DNA. 相似文献
39.
No Heading Conventional relativistic quantum mechanics, based on the Klein-Gordon equation, does not possess a natural probabilistic
interpretation in configuration space. The Bohmian interpretation, in which probabilities play a secondary role, provides
a viable interpretation of relativistic quantum mechanics. We formulate the Bohmian interpretation of many-particle wave functions
in a Lorentz-covariant way. In contrast with the nonrelativistic case, the relativistic Bohmian interpretation may lead to
measurable predictions on particle positions even when the conventional interpretation does not lead to such predictions. 相似文献
40.
Brillouin zone spectroscopy of nonlinear photonic lattices 总被引:1,自引:0,他引:1
We present a novel, real-time, experimental technique for linear and nonlinear Brillouin zone spectroscopy of photonic lattices. The method relies on excitation with random-phase waves and far-field visualization of the spatial spectrum of the light exiting the lattice. Our technique facilitates mapping the borders of the extended Brillouin zones and the areas of normal and anomalous dispersion within each zone. For photonic lattices with defects (e.g., photonic crystal fibers), our technique enables far-field visualization of the defect mode overlaid on the extended Brillouin zone structure of the lattice. The technique is general and can be used for photonic crystal fibers as well as for periodic structures in areas beyond optics. 相似文献