Konserttiohjelma 1907-06-13 - [Framsidan]

Helsingfors : Esplanad Kapellet 1907, Helsingfors stentryckeri

Electrical pump & probe and injected carrier losses quantification in Er doped Si slot waveguides

Electrically driven Er3+ doped Si slot waveguides emitting at 1530 nm are demonstrated. Two different Er3+ doped active layers were fabricated in the slot region: a pure SiO2 and a Si-rich oxide. Pulsed polarization driving of the waveguides was used to characterize the time response of the electroluminescence (EL) and of the signal probe transmission in 1 mm long waveguides. Injected carrier absorption losses modulate the EL signal and, since the carrier lifetime is much smaller than that of Er3+ ions, a sharp EL peak was observed when the polarization was switched off. A time-resolved electrical pump & probe measurement in combination with lock-in amplifier techniques allowed to quantify the injected carrier absorption losses. We found an extinction ratio of 6 dB, passive propagation losses of about 4 dB/mm, and a spectral bandwidth > 25 nm at an effective d.c. power consumption of 120 μW. All these performances suggest the usage of these devices as electro-optical modulators.

Naapurit meistä ja me heistä

Kirjallisuusarvostelu

Vodkaa, Viola-juustoa ja merkkifarkkuja

Kirjallisuusarvostelu

Lapsuuden toverille

Myös Zonophone/Gramophone G.C.-80614 ja 280362.

Porilaisten marssi

Myös Zonophone/Gramophone G.C.-8060.

Lapsuuden toverille

Suomalainen kansansävelmä.

Äänikävely Hämeenpuistossa : Hämeenpuisto soundwalk : 7.5 - 8.6.2012

Näyttely: Äänikävely Hämeenpuistossa : Hämeenpuisto soundwalk 7.5 - 8.6.2012 Sisältö: 1. Hanna Tullila: Vaari ; Aleksei Melnik: Anachronism ; Timo Piikkilä: Adrift - Kymmenentuhatta kilomertiä ; Sirkku Niskanen: Lauri Viita Hämeenpuistossa ; Laura Lehtinen: Pikkuriikkisten matkassa ; Jemina Lindholm: Akvaariot ; Inga Weber: Metsässä ; Niko Skorpo: Chronoscopia

Spin-electromagnetic waves spectra in multiferroic heterostructures

This work devotes to the theoretical investigations of spin-electromagnetic waves (SEW) propagating in a thin-film multiferroic structures that were composed of a slot-line and structures with several ferrite films. In contrast to earlier works, the spin-electromagnetic waves in the investigated structures are originated from two different electrodynamics coupling. The first one is coupling of the electromagnetic wave localized mainly in the slot-line with the spin wave excited mostly in the ferrite film. The second one is coupling of two spin waves in the different ferrite films separated by a thin ferroelectric film. For theoretical analysis of SEWs propagation in such kind of structures theories of their eigen-wave spectra were developed. Spectra of SEW in the investigated structures were calculated and analyzed. The range of electric and magnetic tunability of dispersion characteristic were investigated. Spectra of SEW in the investigated multiferroic structures are used for investigation of transfer function of periodic structures.

A natureza histórico-social da personalidade

Este artigo analisa o processo de formação da personalidade a partir da perspectiva do materialismo histórico e dialético. Esse processo ocorre em interação com as condições sociais objetivas da vida do indivíduo. Somente por meio da análise das alienadas relações sociais capitalistas é possível compreender-se a construção da subjetividade na sociedade contemporânea. Baseado nas contribuições teóricas de Lucien Sève e Aleksei N. Leontiev, este artigo formula uma análise crítica das abordagens que conceituam a personalidade como algo existente independentemente das atividades sociais. Essa análise do papel que as relações sociais desempenham na formação da personalidade é fundamental se se pretende descobrir maneiras concretas pelas quais a sociedade pode promover o máximo desenvolvimento de cada indivíduo.

A educação escolar e a relação entre o desenvolvimento do pensamento e a apropriação da cultura: a psicologia de A. N. Leontiev como referência nuclear de análise

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

O ensino da recepção estético-lierária e a formação humana

In this article are defended the possibility and the necessity of the teaching of the reception of art works in school education. Firstly, some relations between art and the development of both the human species and the individual are analysed in Georg Lukács and Lev Vygotsky’s works. In order to put in question the old assumption that opposes education and instruction, the discussion made by Gramsci on the grammatical teaching of Latin and Greek in the traditional school education is explored. In the article is concluded its path analysing the intentional and systematic formation of the reception of art works provided by school education based on Aleksei N. Leontiev’s works on the appropriation process of culture by the individual.

The Bologna Stone: history's first persistent luminescent material

In 1603, the Italian shoemaker Vincenzo Cascariolo found that a stone (baryte) from the outskirts of Bologna emitted light in the dark without any external excitation source. However, the calcination of the baryte was needed prior to this observation. The stone later named as the Bologna Stone was among the first luminescent materials and the first documented material to show persistent luminescence. The mechanism behind the persistent emission in this material has remained a mystery ever since. In this work, the Bologna Stone (BaS) was prepared from the natural baryte (Bologna, Italy) used by Cascariolo. Its properties, e. g. impurities (dopants) and their valences, luminescence, persistent luminescence and trap structure, were compared to those of the pure BaS materials doped with different (transition) metals (Cu, Ag, Pb) known to yield strong luminescence. The work was carried out by using different methods (XANES, TL, VUV-UV-vis luminescence, TGA-DTA, XPD). A plausible mechanism for the persistent luminescence from the Bologna Stone with Cu+ as the emitting species was constructed based on the results obtained. The puzzle of the Bologna Stone can thus be considered as resolved after some 400 years of studies.