Flash Memory Cells Reliability Parameters Investigation

The present work is a part of the large project with purpose to qualify the Flash memory for automotive application using a standardized test and measurement flow. High memory reliability and data retention are the most critical parameters in this application. The current work covers the functional tests and data retention test. The purpose of the data retention test is to obtain the data retention parameters of the designed memory, i.e. the maximum time of information storage at specified conditions without critical charge leakage. For this purpose the charge leakage from the cells, which results in decrease of cells threshold voltage, was measured after a long-time hightemperature treatment at several temperatures. The amount of lost charge for each temperature was used to calculate the Arrhenius constant and activation energy for the discharge process. With this data, the discharge of the cells at different temperatures during long time can be predicted and the probability of data loss after years can be calculated. The memory chips, investigated in this work, were 0.035 μm CMOS Flash memory testchips, designed for further use in the Systems-on-Chips for automotive electronics.

FLASH-OFDM System Performance Studies for Wireless Broadband Network Operator Services

@450 wireless broadband service is Digita’s mobile wireless broadband network service. In @450 network Digita acts as the network operator offering network capacity to service operators. For Digita it is important to know what kind of services its network is capable of and what are the network’s service parameters. The knowledge of the network parameters and the behaviour can be used in advance in the development of new service products. Before a new service product can be offered to service operators a lot of work has to be done. The basic testing is necessary to get an understanding of the basic functionality. The requirement specification has to be done and a new product has to be created. The new product has to be tested. The test results have to be analysed in order to find out if the new product is suitable for real use and with which limitations. The content of this Thesis is the development of wireless technologies, @450 service and network, FLASH-OFDM technology, FLASH-OFDM performance testing and the development of a new service product.

Elokuva Internetissä : katsaus elokuvaan verkossa sekä suunnitelma Uhripuu-elokuvan julkaisemisesta

Opinnäytetyössäni tarkastellaan Internet-elokuvan historiaa sekä nykyistä tilaa. Käyn läpi yleisimmät katseluohjelmat: QuickTime Player, Windows Media Player, RealPlayer ja Flash Player sekä Internet-elokuvasivustot: YouTube, IFILM, AtomFilm ja Pixoff.net. Kerron myös Flash-elokuvista ja siitä miten Internet on luonut kokonaan uuden elokuvan muodon sekä Internetissä julkaistuista Dogma 2001 The New Rules for Internet Cinema -säännöistä. Käsittelen myös lyhyesti miten Internet-elokuva on vaikuttanut perinteiseen elokuvaan. Käsittelen perinteisen, isolta ruudulta katsottavaksi tehdyn, elokuvan julkaisemista Internetissä. Tarkastelen kahta verkossa julkaistua elokuvaa: Star Wreck ja The Silent City ja käyn läpi miksi ne on julkaistu Internetissä. Star Wreck on tamperelainen poikkeuksellisen kunnianhimoinen amatööriprojekti. The Silent City on taas irlantilaisen 3D-animaattorin, Ruairi Robinsonin, lyhytelokuva, jonka hän on tehnyt työnäytteeksi Hollywoodiin. Käsittelen myös ohjaaja David Lynchin verkkosivut, koska ne ovat Internetissä ainoaa laatuaan ja mainio ympäristö elokuvan julkaisemiseen. Kerron oman Uhripuu-kauhuelokuvani synnystä ja tekoprosessista. Uhripuun idea sai alkunsa Iso-Britanniassa vuoden 2004 alussa. Käsikirjoitus sai lopullisen muotonsa keväällä 2006. Käsittelen miksi ja miten se julkaistaan Internetissä. Kerron elokuvan Internet-sivujen sisällöstä ja sen jaosta eri osiin: Tarina, Rooleissa, Tekijät, Uhripuista, Traileri, Näin tehtiin, Kuvagalleria, E-kortti, Näe/Katso elokuva. Koska olen saanut koulutukseni nimenomaan verkkoviestinnän enkä audiovisuaalisen viestinnän puolella, Uhripuu-elokuvan tekoprosessi on ollut minulle elokuvakoulu. Sen tekemisen aikana olen oppinut elokuvan tekemisestä paljon. Elokuva kuvattiin HD-tarkkuuksilla, jotta kuva ei kärsisi liikaa jälkikäsittelyssä. Mitä tulee elokuvan ja Internetin yhteiseen tulevaisuuteen, näyttää siltä, että nämä kaksi mediaa ovat yhdistymässä yhä enemmän toisiinsa.

Photodamage to Oxygen Evolving Complex - An Initial Event in Photoinhibition of Photosystem II.

Photosystem II (PSII) of oxygenic photosynthesis is susceptible to photoinhibition. Photoinhibition is defined as light induced damage resulting in turnover of the D1 protein subunit of the reaction center of PSII. Both visible and ultraviolet (UV) light cause photoinhibition. Photoinhibition induced by UV light damages the oxygen evolving complex (OEC) via absorption of UV photons by the Mn ion(s) of OEC. Under visible light, most of the earlier hypotheses assume that photoinhibition occurs when the rate of photon absorption by PSII antenna exceeds the use of the absorbed energy in photosynthesis. However, photoinhibition occurs at all light intensities with the same efficiency per photon. The aim of my thesis work was to build a model of photoinhibition that fits the experimental features of photoinhibition. I studied the role of electron transfer reactions of PSII in photoinhibition and found that changing the electron transfer rate had only minor influence on photoinhibition if light intensity was kept constant. Furthermore, quenching of antenna excitations protected less efficiently than it would protect if antenna chlorophylls were the only photoreceptors of photoinhibition. To identify photoreceptors of photoinhibition, I measured the action spectrum of photoinhibition. The action spectrum showed resemblance to the absorption spectra of Mn model compounds suggesting that the Mn cluster of OEC acts as a photoreceptor of photoinhibition under visible light, too. The role of Mn in photoinhibition was further supported by experiments showing that during photoinhibition OEC is damaged before electron transfer activity at the acceptor side of PSII is lost. Mn enzymes were found to be photosensitive under visible and UV light indicating that Mn-containing compounds, including OEC, are capable of functioning as photosensitizers both in visible and UV light. The experimental results above led to the Mn hypothesis of the mechanism of continuous-light-induced photoinhibition. According to the Mn hypothesis, excitation of Mn of OEC results in inhibition of electron donation from OEC to the oxidized primary donor P680+ both under UV and visible light. P680 is oxidized by photons absorbed by chlorophyll, and if not reduced by OEC, P680+ may cause harmful oxidation of other PSII components. Photoinhibition was also induced with intense laser pulses and it was found that the photoinhibitory efficiency increased in proportion to the square of pulse intensity suggesting that laser-pulse-induced photoinhibition is a two-photon reaction. I further developed the Mn hypothesis suggesting that the initial event in photoinhibition under both continuous and pulsed light is the same: Mn excitation that leads to the inhibition of electron donation from OEC to P680+. Under laser-pulse-illumination, another Mn-mediated inhibitory photoreaction occurs within the duration of the same pulse, whereas under continuous light, secondary damage is chlorophyll mediated. A mathematical model based on the Mn hypothesis was found to explain photoinhibition under continuous light, under flash illumination and under the combination of these two.