Structure and properties of samarium overlayer and Sm/Rh surface alloy on Rh(100)

The structure and properties of Sm overlayer and Sm/Rh surface alloy have been investigated with Auger electron spectroscopy (AES), low energy electron diffraction (LEED), X-ray photoelectron spectroscopy (XPS), and temperature programmed desorption spectroscopy (TDS). The growth of Sm on Rh(100) at room temperature (RT) appears following the Stranski-Krastanov growth mode and only the trivalent state Sm is observed from XPS results. Thermal treatment of the Sm film at 900 K leads to the formation of ordered surface alloy which shows the c(5 root2 x root2)R45 degrees and c(2 x 2) LEED patterns. Annealing the Sm film at temperature above 400 K makes the binding energy (B.E.) of Sm 3d(5/2) shift to higher energy by 0.7 eV, which indicates charge transfer from Sm to Rh(100) substrate, causing the increase of CO desorption temperature.

Wideband antireflection film fabricated by glancing angle deposition

Graded-index ZrO2 films has been fabricated on K9 glass by glancing angle deposition. Because the index mismatch at the interface has been reduced, the film results in wideband high-transmission antireflection. From 400nm to 1200nm, the film reflection is lower than 0.8% and the lowest value is 0.2% at 432nm.

Adaptive holographic pumping of thin-film organic lasers

In this Letter, we use a reconfigurable hologram to dynamically control the position of incidence of the pump beam onto a liquid-crystal dye-based laser. The results show that there is an increase in the stability of the laser output with time and the average power when compared with the output of the same laser when it is optically excited using a static pump beam. This technique also provides additional functionality, such as wavelength tuning and spatial shaping of the pump beam, both of which are demonstrated here. © 2013 Optical Society of America.

Cathodoluminescence study of GaN-based film structures

GaN films grown on sapphire substrate with an emphasis on epitaxial lateral overgrown (ELOG) layers with an array of rhombic shaped mask area as well as InGaN/GaN MQW laser diode layer structures were investigated by cathodoluminescence (CL) spectroscopy and CL imaging at room and low temperatures. The microscopic imaging with a high-spatial resolution clearly reveals the distribution of threading dislocations and point defects in ELOG GaN films. The secondary electron and CL data measured on cleaved faces of laser diodes are analyzed in consideration with luminescence mechanisms in semiconductor heterostructures and around the p - n junction, providing important information on the defects and carrier dynamics in laser diode devices.

Evaluation of both composition and strain distributions in InGaN epitaxial film using x-ray diffraction techniques

The composition and stain distributions in the InGaN epitaxial films are jointly measured by employing various x-ray diffraction (XRD) techniques, including out-of-plane XRD at special planes, in-plane grazing incidence XRD, and reciprocal space mapping (RSM). It is confirmed that the measurement of (204) reflection allows a rapid access to estimate the composition without considering the influence of biaxial strain. The two-dimensional RSM checks composition and degree of strain relaxation jointly, revealing an inhomogeneous strain distribution profile along the growth direction. As the film thickness increases from 100 nm to 450 nm, the strain status of InGaN films gradually transfers from almost fully strained to fully relaxed state and then more in atoms incorporate into the film, while the near-interface region of InGaN films remains pseudomorphic to GaN.

Enhance the optical absorptivity of nanocrystalline TiO2 film with high molar extinction coefficient ruthenium sensitizers for high performance dye-sensitized solar cells

We report two new heteroleptic polypyridyl ruthenium complexes, coded C101 and C102, with high molar extinction coefficients by extending the pi-conjugation of spectator ligands, with a motivation to enhance the optical absorptivity of mesoporous titania film and charge collection yield in a dye-sensitized solar cell. On the basis of this C101 sensitizer, several DSC benchmarks measured under the air mass 1.5 global sunlight have been reached.

A new heteroleptic ruthenium sensitizer enhances the absorptivity of mesoporous titania film for a high efficiency dye-sensitized solar cell

A heteroleptic polypyridyl ruthenium complex, cis-Ru(4,4'-bis(5-octylthieno[3,2-b]thiophen-2-yl)-2,2'-bipyridine)(4,4'-dicarboxyl-2,2'-bipyridine)(NCS) 2, with a high molar extinction coefficient of 20.5 x 10(3) M-1 cm(-1) at 553 nm has been synthesized and demonstrated as a highly efficient sensitizer for a dye-sensitized solar cell, giving a power conversion efficiency of 10.53% measured under an irradiation of air mass 1.5 global ( AM 1.5G) full sunlight.

Stimulated emission in the film of polymer/dye blend

Optically pumped stimulated emission behavior in an organic film was demonstrated in this study. The gain material consists of a laser dye perylene doped into polystyrene (PS) matrix in an appropriate weight ratio. The sample was transversely pumped by the three harmonic output of a mode-locked Nd:YAG laser. The change of the emission spectra showed a clear threshold action and gain narrowing phenomenon when increasing the excitation intensity. Three emission peaks were observed below the excitation threshold, which are locate at 446, 475 and 506 nm, respectively. However, only the gain narrowing peak centered at 475 nm could be detected above the threshold. The spectra narrowing observed results from the amplified spontaneous emission (ASE) in the gain material. (C) 2000 Elsevier Science S.A. All rights reserved.

Evidence of extended orientational order in amorphous Fe/Sm thin films

Amorphous thin films of Fe/Sm, prepared by evaporation methods, have been magnetically characterized and the results were interpreted in terms of the random magnets theory. The samples behave as 2D and 3D random magnets depending on the total thickness of the film. From our data the existence of orientational order, which greatly influences the magnetic behavior of the films, is also clear.

Små citroner gula : En studie i hur estetiska lärprocesser iscensätts, värderasoch realiseras, samt hur en lärmiljö med – ”The Wow Factor”påverkar inlärning på gymnasienivå

Uppsatsens syfte är att studera hur estetiska lärprocesser används för att stimulera lärandet och utveckla eleverna på gymnasial nivå i ämnet religionskunskap. För att få svar har under-sökningen fokuserat på hur estetiska lärprocesser iscensätts i praktiken, kopplat till teori om hur dessa lärprocesser kan påverka och stimulera elevens utveckling och lärande. Studien grundar sig på kvalitativa intervjuer gjorda på två olika skolor, en privat skola och en kom-munal med gymnasielärare i ämnet religion. Intervjutexterna har tolkats hermeneutiskt för att inte bara synliggöra samtalet mellan informanter och forskare, utan även belysa den tolkade texten som på så sätt även den kan ses som ett samtal mellan tolkare, läsare och text. Studien har använt ett teoretiskt ramverk där tre teoretiska perspektiv belyst estetiska lärprocesser samt kringliggande problematik i ämnet. Studien är av komparativ art och analysverktygen har selekterats utifrån tanken att med olika teoretikers perspektiv bemöta och besvara studiens frågeställningar.Resultatet påvisar att det råder en tveksamhet om vad som kan betraktas som estetiska lärpro-cesser och vad som ska inkluderas i begreppet bland informanterna. Dock råder en samstäm-mighet i att det rör sig om praktiskt, kreativt engagemang i grupp som kännetecknar estetiken i verksamheten. Värderingsfrågan visade sig ha två dimensioner. Den ena aspekten var att in-formanterna värderade de estetiska lärprocesserna högt som ur motivations-, engagemangs- och personlighetsutvecklande perspektiv. Däremot värderades de estetiska lärprocesserna lågt ur ett betygsgrundande perspektiv.De estetiska lärprocesserna iscensätts främst genom film, möten och miljöbyten. Film an-vänds främst som visuell och känslomässig förstärkning av undervisningens valda innehåll. Möten med personer aktiva inom det aktuella undervisningstemat används i lika stor utsträck-ning för att öka elevernas minnesförnimmelse och engagemang samt verklighetsrelatering, det vill säga koppling till extern kunskap. Möten kunde även i mer abstrakt betydelse innefatta möten med andra, redan befintliga kulturer i dess omgivning som synliggjorts genom den estetiska lärprocessen.Fördelarna med att använda sig av de estetiska lärprocesserna i undervisningen visade sig i huvudsak vara att de skapade utrymme för känslor och att de bidrar till en större studiemoti-vation samt ett ökat engagemang bland eleverna. Respekt för andra människor ur ett sociokul-turellt perspektiv var vad informanterna anser att de estetiska lärprocesserna genererar i ett vidgat lärande perspektiv, det vill säga ett externt lärande. Nackdelarna kan sammanfattas med de bristande resurser som stod till pedagogernas förfogande i form av tid och utbildning i ämnet, vilket i hög grad kom att belysa bedömningsproblematiken.

Investigation of RuO2/Ta2O5 thin film evolution by thermogravimetry combined with mass spectrometry

The thermal evolution process of RuO2–Ta2O5/Ti coatings with varying noble metal content has been investigated under in situ conditions by thermogravimetry combined with mass spectrometry. The gel-like films prepared from alcoholic solutions of the precursor salts (RuCl3·3H2O, TaCl5) onto titanium metal support were heated in an atmosphere containing 20% O2 and 80% Ar up to 600 °C. The evolution of the mixed oxide coatings was followed by the mass spectrometric ion intensity curves. The cracking of retained solvent and the combustion of organic surface species formed were also followed by the mass spectrometric curves. The formation of carbonyl- and carboxylate-type surface species connected to the noble metal was identified by Fourier transform infrared emission spectroscopy. These secondary processes–catalyzed by the noble metal–may play an important role in the development of surface morphology and electrochemical properties. The evolution of the two oxide phases does not take place independently, and the effect of the noble metal as a combustion catalyst was proved.