Preparation of GaAs₁-ₓPₓ compounds from the melt under controlled vapour pressures

Crystalline solid solutions between GaAs and GaP compounds were prepared from the melt under controlled vapour pressures. The experimental results were found to agree with the theoretical formulae derived in order to calculate the pseudo-equilibrium in a heterogeneous system consisting of two parts with different temperatures. It was assumed that all condensed phases would be regular or sub-regular and that the gas phase is ideal. In addition some of the thermodynamic properties of the Ga-As-P ternary system were dicussed. It was confirmed that one can apply the concept of the pseudo-equilibrium to preparation of crystalline solid solutions of III-V compounds containing two volatile components

Infrared Absorption in Gallium Arsenide-Gallium Phosphide Alloys

The infrared absorption has been quantitatively investigated with respect to the shape, the temperature dependence and the carrier concentration dependence of the additional absorption band in the region from 1000 to 4000 cm⁻¹. The experimental method for the determination of the threshold energy was discussed. The present experimental results have given a reasonably clear indication of the difference between the additional absorptions in n-GaAs-rich alloys and ones in n-GaP-rich alloys. Especially, the additional bands in n-GaAs-rich alloys were concluded to occur by a transition of conduction electron from the lowest band minimum to the upper subsidiary one. The dependence of the threshold energy on composition x was found to be expressed as Eₜ＝0.29-0.67x (eV). The empirical cross over point occurred at 43 mol% GaP. On the other hand, in n-GaP and GaP-rich alloys, the additional band showed a relatively sharp peak and all the absorption shapes were similar to the previous analysis. The threshold energy was found to depend to a small extent on the composition. The dependence could be illustrated in terms of the composition dependence of the ionization energy

Mechanical and Superconducting Properties of Multifilamentary Nb₃Sn Composites

The interrelation of mechanical and superconducting properties with the microstructure of multifilamentary composites has been investigated. The fracture behaviour changed depending on the growth of the compound layer. When the layer is thin, multiple fracture is observed and the composite can be plastically deformed with a large elongation. On the other hand, when the heat tratment progresses and the layer thickness becomes thicker, the whole composite fractures at once after a small elastic elongation. There exists a critical thickness dividing these two modes, which has been determined theoretically as well as experimentally. The maximum global pinning force can be well described as a function of the inverse grain size of the compound. The strength of the compound is also made clear so as to be expressed as a function of the inverse grain size. Finally, we propose the structure of composites and the conditions of heat treatment to optimize both properties mentioned above

Electrical and Optical Properties of Te doped GaSb

To examine the property of impurity states in n- and p-type GaSb, the crystals were prepared by doping it with Te. The Hall and resistivity measurements were made and, simultaneously, the free carrier absorption was measured. The undoped crystals were always p-type. The perfect compensation was found to occur at the 0.003 at% amount of Te added to the melt. In the p-type GaSb, it was found that the acceptor level, which results from vacancies in Sb sub-lattice site, is located at 0.021 eV. In the n-type GaSb, the donor concentration changed from 0.5 to 10 x10¹⁸cm⁻³ by increasing the Te amount. It was suggested that the acceptor introduced into the n-type crystal corresponds to the deeper acceptor level, which was observed in the highly compensated p-type sample. The concentration of its acceptor was found to be fairly larger than that of the native acceptor

Muisti ja Arki : Ajankohtaista tietoa muistisairauksista, niiden ennaltaehkäisemisestä sekä arjesta muistisairauden kanssa

Suomen väestön ikärakenne muuttuu nopeasti lähivuosikymmeninä. Tilastokeskuksen ennusteiden mukaan yli 75-vuotiaiden määrä kaksinkertaistuisi vuoteen 2030 mennessä, joten muistisairauksien esiintyvyys tulee myös lisääntymään ikääntyvien määrän kasvaessa. Opinnäytetyömme idea sai alkunsa SenioriKaste-hankkeelta, joka toivoi ensitietopäivän järjestämistä Keski-Pohjanmaan alueella muistisairauksiin sairastuneille sekä heidän läheisilleen. Opinnäytetyömme tarkoituksena oli järjestää muistisairauksia käsittelevä tilaisuus muistisairauteen sairastuneille sekä heidän läheisilleen. Tilaisuus oli myös avoin kaikille asiasta kiinnostuneille. Opinnäytetyömme tavoitteena oli välittää muistisairauteen sairastuneille ja heidän läheisilleen ajankohtaista tietoa muistisairauksista sekä keinoista, joiden avulla kotona pärjääminen onnistuu mahdollisimman pitkään. Kartoitimme yhteistyökumppaneidemme kautta aiheen tärkeyttä ja tarvetta. Heidän asiakkailtaan saadun palautteen perusteella varmistuimme tilaisuuden järjestämisen tärkeydestä ja tiedon tarpeellisuudesta. Opinnäytetyömme toteutui toiminnallisena projektityönä yhteistyössä toimeksiantajan SenioriKaste-hankkeen kanssa Kokkolassa 4.6.2015. Tilaisuudessa luennoitiin muistisairauksien ennaltaehkäisemisestä, yleisimmistä muistisairauksista, muistisairauksien varhaisesta tunnistamisesta sekä niiden tuomista haasteista ja vaikutuksista ihmisen jokapäiväiseen elämään. Tilaisuuteen osallistui yhteensä 140 henkilöä. Osallistujilta kerättiin kirjallinen palaute. Palautekyselyistä tehtiin yhteenveto ja kehittämisehdotukset kirjattiin myös opinnäytetyöhön. Tilaisuus vastasi yleisesti osallistujien odotuksia kiitettävästi. Projekti toteutettiin parityöskentelynä, jossa onnistuimme kiitettävästi.The age structure of Finnish population is changing rapidly within the next few decades. Statistics prognosis is that the number of over 75 years old people will be doubled by 2030, so the occurrence of memory disorders will increase with aging people. The idea for this study got its start from Senior Initiation project that wished a public lecture to be organized in Central Ostrobothnia for patients with memory disorder and their families. The purpose of our study was to organize a memory disorder event for the aforementioned groups. The occasion was open for anyone who was interested in it. The aim of this study was to provide current information to memory disorder patients and their loved ones about memory disorders and ways to cope with it at home as long as possible. Through our co-operation partners we surveyed the importance and need of the topic. Based on the feedback from their clients we were convinced of the importance of the event and the need for information. Our thesis was completed as a functional project work together with our client Senior Initiation project in Kokkola 4th of June 2015. The prevention of memory disorders, most common memory disorders, their early recognition and the challenges and effects they bring to people’s everyday lives were discussed during this event. The total of 140 people took part in the event. A written feedback was collected from all participants. A summary was made from the feedback survey, and all development proposals were registered also in this thesis. The event corresponded in general to the participants’ expectations very well. The project was implemented as pair work, in which we succeeded commendably

Reversion Characteristics in an Al-4wt%Cu Alloy

The X-ray diffuse scattering intensity around the 110 reciprocal lattice point was measured in order to determine quantitatively the amount and size of precipitates during ageing and reversion. The precipitated phase was definitely determined by the aids of Laue X-ray photographs and the electron diffraction patterns. The electrical resistivity was carefully measured. When the alloy was aged for 1000 min at 373K, the GP zones precipitated with a mean diameter of 8.0nm. During the reversion, those zones dissolved perfectly above 458K, which is in good agreement with the result of Beton and Rollason. After the perfect dissolution of the GP zones, the Θ′ phase precipitated directly and heterogeneously. By ageing for 4000 min at 408K, the Θ″ phase precipitated with a mean diameter of 12.5 nm. When its aged alloy was reverted, the temperature at which the volume fraction of precipitates becomes minimum, but not zero, was 498K, where the successively precipitated Θ′phase exsisted already

ガリウム ト 5ゾク ゲンソ ト ノ カゴウブツ オヨビ インジウム セレナイド カゴウブツ ノ チョウセイ ト セイシツ ニ カンスル ケンキュウ

京都大学0048新制・課程博士工学博士甲第1049号工博第236号新制||工||172(附属図書館)UT51-46-A583京都大学大学院工学研究科冶金学専攻(主査)教授 村上 陽太郎, 教授 盛 利貞, 教授 森山 徐一郎学位規則第5条第1項該当Kyoto UniversityDFA