33,304 research outputs found
Electrical phase change of CVD-grown Ge-Sb-Te thin film device
No full textA prototype Ge-Sb-Te thin film phase-change memory device has been fabricated and reversible threshold and phase change switching demonstrated electrically, with a threshold voltage of 1.5 – 1.7 V. The Ge-Sb-Te thin film was fabricated by chemical vapour deposition (CVD) at atmospheric pressure using GeCl4, SbCl5, and Te precursors with reactive gas H2 at reaction temperature 780 °C and substrate temperature 250 °C. The surface morphology and composition of the CVD-grown Ge-Sb-Te thin film has been characterized by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The CVD-grown Ge-Sb-Te thin film shows promise for the phase change memory applications
395. Tsukigarisen-ge ou Gesshakusen-ge
No full textIwao Seiichi, Iyanaga Teizō, Ishii Susumu, Yoshida Shōichirō, Fujimura Jun'ichirō, Fujimura Michio, Yoshikawa Itsuji, Akiyama Terukazu, Iyanaga Shōkichi, Matsubara Hideichi. 395. Tsukigarisen-ge ou Gesshakusen-ge. In: Dictionnaire historique du Japon, volume 19, 1993. Lettre T. p. 148
Deposition and characterization of CVD-grown Ge-Sb thin film device for phase-change memory application
No full textGermanium antimony (Ge-Sb) thin films with tuneable compositions have been fabricated on SiO2/Si, borosilicate glass, and quartz glass substrates by chemical vapour deposition (CVD). Deposition takes place at atmospheric pressure using metal chloride precursors at reaction temperatures between 750 and 875 °C. The compositions and structures of these thin films have been characterized by micro-Raman, scanning electron microscope (SEM) with energy dispersive X-ray analysis (EDX), and X-ray diffraction (XRD) techniques. A prototype Ge-Sb thin film phase-change memory device has been fabricated and reversible threshold and phase change switching demonstrated electrically, with a threshold voltage of 2.2 - 2.5 V. These CVD-grown Ge-Sb films show promise for applications such as phase change memory and optical, electronic and plasmonic switching
As equações algébricas no ensino médio: um estudo de uma sequência didática utilizando software gráfico
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina. Programa de Pós-Graduação em Educação Científica e Tecnológica.O presente trabalho apresenta um estudo sobre o ensino das equações algébricas no ensino médio. Na prática docente e em alguns livros didáticos percebemos a ênfase dada aos algoritmos para a resolução de equações algébricas, enquanto as soluções ficam restritas ao conjunto dos números racionais e números complexos imaginários. A análise de alguns documentos oficiais tais como Parâmetros Curriculares Nacionais e Orientações Curriculares para o ensino médio mostra a possibilidade de se ensinar outros métodos de resolução. Adotamos conceitos da Didática da Matemática como quadro teórico de referência. Apoiamo-nos em elementos da Transposição Didática de Yves Chevallard para estudar o desenvolvimento histórico do saber Equações Algébricas até a proposição em livros didáticos. Para conhecer a Praxeologia Matemática em livros didáticos, adotamos elementos da Teoria Antropológica do Saber de Chevallard. A metodologia de pesquisa baseou-se em elementos teóricos da Engenharia Didática. Aplicamos uma seqüência didática a alunos de ensino médio em que alguns exercícios podiam ser resolvidos pelas técnicas freqüentemente empregadas. Uma das equações, no entanto, não podia ser resolvida pelos algoritmos usuais, pois apresentava como solução um número irracional. Apresentamos aos alunos noções de um método numérico e um software gráfico para auxiliar o trabalho de localização de raízes reais. Além de apresentarmos as transformações pelas quais passa o objeto Equações Algébricas, da forma como foi concebido até como saber a ensinar por meio do livro didático, esse trabalho pode subsidiar discussões acerca da prática docente apoiada por programas computacionais
OU SHAREOK Proxy Licensing Agreement
No full textThose uploading work to SHAREOK on behalf of others must have written permission from the author(s) granting a license via the SHAREOK Proxy Licensing Agreement. This written permission will be uploaded with its associated file(s) and hidden from public view. For additional information see the “Student Work in SHAREOK” section of SHAREOK Institutional Repository: OU Policies and Guidelines at https://shareok.org/handle/11244/330071; however, this Proxy Licensing Agreement is not limited to student work
Projeção liquidus do sistema Ta-Ge-B
No full textCurrent technological progress has demanded materials that can maintain their physi cal and chemical properties and integrity when submitted to high mechanical stress for
long periods and high temperatures. Ni-based superalloys belong to a class of materials
currently used in these conditions, but they have reached their limit of development and,
therefore, there is a demand for materials that can complement them. Among the materials
with this potential it can be highlighted those based on multiphase microstructures of MR
(Refractory Metals) in thermodynamic equilibrium with intermetallics. The most promis ing results have been obtained with alloys based on Nb-Si-B or Mo-Si-B. A good example
is the MoSi2 phase, as it has a high melting point, 2020 °C, and excellent resistance to oxi dation at high temperatures, however, its toughness and mechanical strength are low, but
if this phase reaches thermodynamic equilibrium with a refractory metal, this metal can
impart the necessary ductility to the alloy. Due to the similarities in chemical structure
existing between the pairs Nb, Si and Ta, Ge, this last pair of chemical elements can be
used to stabilize a desired microstructure and, in addition, they can control diffusion and
oxidation resistance. Thus, the study of the Ta-Ge-B system can be important to assist
in the development of these alloys, especially if associated with thermodynamic modeling
by the CALPHAD method. No information on the liquidus projection or thermodynamic
modeling of the Ta-Ge-B system was found in the literature. Thus, this work presents the
experimental study of the liquidus projection of the Ta-Ge-B system through the analy sis of the solification structure of 17 alloys associated with thermodynamic calculations
by the CALPHAD method. As a result, a partial proposal for the liquidus projection is
presented for the first time in the literature.O progresso tecnológico da atualidade tem demandado materiais que possam manter as
suas propriedades e integridade física e química quando submetidos a grandes esforços
mecânicos por longos períodos e temperaturas elevadas. As superligas à base de Ni per tencem a uma classe de materiais atualmente usados nessas condições, mas tem chegado
ao seu limite de desenvolvimento e, por isso, há uma demanda de materiais que possam
complementá-las. Dentre os materiais com este potencial estão aqueles constituídos de mi croestruturas multifásicas de MR (Metais Refratários) em equilíbrio termodinâmico com
intermetálicos. Os resultados mais promissores têm sido obtidos com as ligas baseadas em
Nb-Si-B ou Mo-Si-B. Um bom exemplo é a fase MoSi2, pois apresenta um alto ponto de
fusão, 2020 °C, e excelente resistência à oxidação em altas temperaturas, no entanto, sua
tenacidade e resistência mecânica são baixas, mas se essa fase entrar em equilíbrio termo dinâmico com um metal refratário, este metal pode conferir a ductibilidade necessária a
liga. Devido às semelhanças na estrutura química existentes entre os pares Nb, Si e Ta,
Ge, esse par de elementos químicos apresentados por último pode ser usado para estabi lizar uma microestrutura desejada e, além disso, podem controlar a difusão e resistência
à oxidação. Assim, o estudo do sistema Ta-Ge-B pode ser importante para auxiliar no
desenvolvimento destas ligas principalmente, se associado a modelagem termodinâmica
pelo método CALPHAD. Não foram encontradas na literatura, informações sobre a pro jeção liquidus ou modelagem termodinâmica do sistema Ta-Ge-B . Assim, este trabalho
apresenta o estudo experimental da projeção liquidus do sistema Ta-Ge-B através da aná lise da estrutura de solidificação de 17 ligas associada aos cálculos termodinâmicos pelo
método CALPHAD. Como resultado, uma proposta parcial para a projeção liquidus é
apresentada pela primeira vez na literatura
Les salariés des GE gagnants ou perdants?
No full textLes groupements d’employeurs (GE) sont présentés comme des dispositifs permettant de concilier les besoins des entreprises et des travailleurs. On évoque toujours un modèle « gagnant-gagnant ». L’entreprise gagne à recourir aux services des GE. Tester cette hypothèse nous est apparu moins pertinent, d’abord parce que l’entreprise étant rationnelle, si elle s’adresse au GE, c’est qu’elle y trouve un intérêt ; ensuite les avantages des entreprises à uti..
Educational drama in the teaching of education for sustainability
No full textIn this paper, I describe part of my research project that examines the use of Educational Drama in Education for Sustainability in the upper stages of the primary school (10- and 11-year-olds). Central to the research is a small-scale qualitative research study. Here, I describe the educational focus of the study and outline the methodology. Central to the study was a series of drama lessons (taught by me) based on environmental themes. The lessons link with some of the key aims in Education for Sustainability - to help young people to develop awareness, knowledge and concepts, to encourage positive attitudes and personal lifestyle decisions and to help them to acquire action skills in and for the environment. The locus is within the Scottish education system. A number of key data were generated during the teaching and evaluation of the lessons. These take the form of field notes, children's evaluations of their work and learning, observation schedules, taped interviews with participants and observers and videotapes of the lessons. The analysis of the data is ongoing, but already there is substantial evidence to suggest that the drama was instrumental in helping the children to achieve the learning outcomes set for the lessons. Some of that evidence is presented here. I suggest that the active, participative learning central to drama is particularly useful for allowing children to develop skills in communication, collaboration and expressing ideas and opinions. Also, the immersion in the imagined context and narrative, integral to the 'stories' in the drama, allows the children to feel sympathy for and empathy with people who are affected by environmental issues and problems. In giving the children a context for research and in helping them to plan solutions and to suggest alternatives, the drama allows the participants opportunities to rehearse active citizenship and facilitates learning in Education for Sustainability
Corrigendum to “General reduced vehicle model for simulating truck-bridge pier collisions” [Dev. Built. Environ. 16 (2023) 100233] (Developments in the Built Environment (2023) 16, (S2666165923001151), (10.1016/j.dibe.2023.100233))
No full textThe authors regret there were two errors in the authors' affiliation in the published article. First, the affiliation of the first author (Daogang Ou) should only be the School of Civil Engineering, Hunan University of Science and Technology, Xiangtan, 411201, China. Second, the corresponding author (Lin Chen) should have two affiliations; the first one should be: School of Civil Engineering, Hunan University of Science and Technology, Xiangtan, 411201, China; and the second one should be: Key Laboratory of Building Safety and Energy Efficiency of Ministry of Education, Hunan University, Changsha, 410082, China. The authors would like to apologise for any inconvenience caused
"Popular author, poet to read at OU"
No full textNews article"One of America's most popular writers will visit OU Friday, Oct. 18. Marge Piercy, award winning author and poet, will read from her poetry at 4 p.m. in 201 Dodge Hall.
- …
