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Dissertations / Theses on the topic 'BARIUM FLUORIDES'

Author: Grafiati

Published: 4 June 2021

Last updated: 16 February 2022

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1

ESPIRITO, SANTO ANA M. do. "Sintese e purificacao de fluoretos para o crescimento de matrizes laser ativas: BaLifsub3 e LiSrAlFsub6." reponame:Repositório Institucional do IPEN, 1997. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10651.

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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

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2

NAKAMURA, GERSON H. de G. "Análise térmica e equilíbrios de fase no sistema BaFsub(2)-YFsub(3)." reponame:Repositório Institucional do IPEN, 2008. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11678.

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Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN/CNEN-SP

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3

VIDAL, AUGUSTO T. "Sintese e crescimento de cristais fluoretos dopados com terras raras: LiCAF:Er e BLF:TR (TR = Yb sup(3+), Ce sup(3+), Nd sup(3+))." reponame:Repositório Institucional do IPEN, 2001. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10970.

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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

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4

SAWADA, LIDIA. "Determinação da difusividade térmica de cristais de BaLiFsub(3) puro e dopado." reponame:Repositório Institucional do IPEN, 2000. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9291.

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Dissertacao (Mestrado)
IPEN/D
Intituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP

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5

METAIRON, SABRINA. "Desenvolvimento de uma metodologia de analise da qualidade cristalina de monocristais." reponame:Repositório Institucional do IPEN, 1999. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10710.

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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

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6

LOPES, ARTUR J. da S. "Sintese e refino por zona de fluoretos para crescimento de cristais laser: BaLiF sub(3):Co sup(2)." reponame:Repositório Institucional do IPEN, 2001. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10960.

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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

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7

DUARTE, MARCOS. "Caracterizacao do BaLiFsub3:Cosup2+ visando sua utilizacao como meio laser ativo .Estudo de suas propriedades espectroscopicas e determinacao da difusidade termica." reponame:Repositório Institucional do IPEN, 1994. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10408.

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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

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8

BALDOCHI, SONIA L. "Sintese e crescimento de cristais de BaLiFsub3 puros e dopados com Pb." reponame:Repositório Institucional do IPEN, 1993. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10336.

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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

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9

Clegg, Paul S. "The chemical and magnetic structures of rare earth alloys and superlattices." Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343299.

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10

HWANG, MIRIAM K. "Analise microestrutural de telureto de chumbo obtido por crescimento epitaxial." reponame:Repositório Institucional do IPEN, 2000. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10829.

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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

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11

LIBRANTZ, ANDRE F. H. "Investigacao dos processos de excitacao multifotonica da configuracao 4fsup(2)5d nos cristais de LiYFsub(4), LuLiFsub(4) e BaYsub(2)Fsub(8) dopados com neodimio trivalente." reponame:Repositório Institucional do IPEN, 2004. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11202.

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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

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12

Jeandel, Gérard. "Influence de quelques impuretés sur les thermo-courants ioniques, et la dynamique de vibration des fluorures de baryum et strontium." Nancy 1, 1987. http://www.theses.fr/1987NAN10192.

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Interprétation de l'absorption IR par un modèle base sur les fonctions de green et nécessitant la connaissance de la dynamique du cristal et de la perturbation due à l'impureté. Les spectres raman de BAF::(2) : DY**(3+) et SRF::(2) : DY**(3+) comportent des raies à des fréquences voisines ; leur position est identique dans un repère de fréquence absolu pour les raies laser différentes. Cette étude a permis l'interprétation des courbes de thermo-courant ionique par l'intermédiaire de constantes diélectriques

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13

Partey, Frederick Kenneh. "SOURCE OF FLUORINE AND PETROGENESIS OF THE RIO GRANDE RIFT TYPE BARITE-FLUORITE-GALENA DEPOSITS." Miami University / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=miami1092262697.

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14

Song, Hang. "Fabrication and characterisation of electrospun polyvinylidene fluoride (PVDF) nanocomposites for energy harvesting applications." Thesis, Brunel University, 2016. http://bura.brunel.ac.uk/handle/2438/12850.

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Three systems of electrospun composite membranes with piezoelectric polymer polyvinylidene fluoride (PVDF) as matrix incorporating: 1) Carbon based fillers: carbon nanotube (CNT) and graphene oxide (GO); 2) Ceramic based fillers-barium titanate (BT), zinc oxide (ZnO) and nanoclays (halloysite and bentonite); 3) Cellulosic fillers: microcrystalline cellulose (MCC) and nanocrystalline cellulose (NCC) at different loadings were prepared by electrospinning process. Influence of filler type and loading on total PVDF crystallinity (Xc), relative fraction of β phase (piezoelectric phase) in total crystalline PVDF (Fβ), volume fraction of β phase in the samples (vβ) and piezoelectric coefficient d33 were characterised and analysed. Correlation between vβ and piezoelectric performance (d33) will be focused by this work. A common situation was observed for the composites-d33 increased while vβ is reduced by the fillers, so it can be concluded that d33 of the composites is not totally up to their vβ, there are other factors that need to be taken into account. For example, for carbon based filler like CNT, it increased electric conductivity of sample during and after electrospinning process, making it easier for charges produced by β crystals from inside of sample to be transferred to surfaces of the sample, and possibly promoting orientation of β crystals in d33 direction, therefore enhanced d33 of the composites though β phase formation was significantly hindered by inclusion of CNT; For piezoelectric ceramic fillers like BT and ZnO, a possible combined piezoelectricity from filler and β phase PVDF might enhanced d33 though less β phase was formed; And for non-piezoelectric and non-conductive fillers, enhancement in orientation of β crystals might play a major role in promotion of d33. Keywords: electrospinning; polyvinylidene fluoride (PVDF); nanocomposites; piezoelectric coefficient d33; energy harvesting.

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15

AYADI, MOHAMED. "Contribution a l'etude de la dynamique de reseau de quelques composes de la serie de la mathlockite (pbfcl)." Université Louis Pasteur (Strasbourg) (1971-2008), 1986. http://www.theses.fr/1986STR13183.

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Etude de l'energie de cohesion de composes a structure de mathlockite; conditions de stabilite, expressions de la polarisation ionique, des constantes d'elasticite et des constantes dielectriques (modele de la coquille, presence de sites non centrosymetriques). Condition de synthese et de croissance cistalline de cahcl, bafcl, pbfcl et biocl; spectres raman et ir. Analyse des spectres de reflexion ir de bafcl (kramers-kronig et oscillateur classique). Determination de la densite d'etats et de la dispersion de phonons pour bafcl; calcul de certaines constantes d'elasticite

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16

Salaeh, Subhan. "Élaboration des composites et mélanges à base de caoutchouc naturel : relations structure - propriétés." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10141/document.

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Le caoutchouc naturel (NR) et le caoutchouc époxydé (ENR) ont constitué la base de cette étude consacrée à l’étude des composites et mélanges de polymères. La présence du groupe époxyde a conduit à une amélioration des propriétés mécaniques de ces formulations en termes de module et de la résistance à la traction. De plus, l’utilisation de la spectroscopie diélectrique a révélé que les ENRs présentent une conductivité plus élevée que le NR à basse fréquence et à haute température. En particulier, le caoutchouc naturel époxidé contenant 50 mol% de groupes époxyde ENR-50 présente des conductivités et permittivités les plus élevées. Par conséquent, ce dernier a été choisi pour préparer des composites polymères en incorporant des particules de titanate de barium (BT) et de noir de carbone (CB). Les résultats montrent que la permittivité et conductivité des composites élaborés augmentent avec le taux d'incorporation de ces charges. Par exemple, les composites BT/ENR-50 atteignent une permittivité élevée 48.7 pour 50 vol% de BT. De plus, les composites CB/ENR-50 présentent un seuil de percolation de 6.3 vol% de CB. Enfin les mélanges à base de poly(fluorure de vinylidène) (PVDF) et d’ENR ont été étudiés. Il a été observé que la morphologie de ces mélanges dépend du degré d’époxydation du caoutchouc naturel et bien entendu de la composition du mélange. Une morphologie co-continue peut être observée dans l’intervalle 40 et 60% en masse d’ENR-50. En outre, les résultats issus d’analyses dynamiques mécanique et diélectrique montrent que ces mélanges présentent une miscibilité partielle. Enfin, des composites à base de ces mélanges binaires PVDF/ENR- 50 contenant BT ont été préparés. L’étude des morphologies a révélé que les particules de BT étaient dispersées dans la phase d’ENR-50 pour le mélange classique. Cependant, les particules de BT sont localisées à l'interface et dans la phase PVDF pour le mélange réticulé dynamiquement. En termes de propriétés, la permittivité plus élevée est obtenue pour le mélange PVDF/ENR 50 (80/20) ayant été réticulé dynamiquement
Natural rubber (NR) and epoxidized natural rubber (ENR) were chosen to study the composites and blends of polymers. The presence of epoxide group caused to improve the mechanical properties in terms of modulus and tensile strength. Furthermore, dielectric spectroscopy revealed that ENR showed conductivity process at low frequency and high temperature. Epoxidized natural rubber containing 50 mol% of epoxide group or ENR-50 exhibited the highest dielectric permittivity and electrical conductivity. Therefore, ENR-50 was then selected to prepare polymer composite filled with barium titanate (BT) and carbon black (CB) particles. The permittivity and conductivity of the composites increased with the volume content of the fillers. The BT/ENR-50 composites reached a high permittivity of 4 8 . 7 for addition of 50 vol% BT. Meanwhile, CB/ENR-50 composite reached percolation threshold at 6. 3 vol% of CB. The phase development and miscibility of poly(vinylidene fluoride) (PVDF)/epoxidixed natural rubber (ENR) blends were then investigated. It was also found that phase structure depended on epoxidation level and blend compositions. The blend exhibited a co-continuous phase morphology in the region of 40 to 60 wt% of ENR-50. Furthermore, the results from dynamic mechanical and dielectric analysis revealed that these blends present a partial miscibility. Finally, the composites based on binary blends of PVDF/ENR-50 containing BT were prepared. The study of the morphologies revealed that BT was dispersed in ENR-50 phase in the case of simple blend. However, the addition of BT after dynamic vulcanization induced localization of BT in PVDF phase and at interface. The highest increment of permittivity can be observed for the composite based on dynamically cured PVDF/ENR-50 (80/20) blend
ศึกษาอิทธิพลของโครงสร้างโมกุลยางธรรมชาติ (NR) และยางธรรมชาติอิพอกไซด์ (ENR) ต่อสมบัติ พบว่าการมีหมู่อิพอกไซด์อยู่ในยาง ENR ทำให้มีการปรับปรุงสมบัติเชิงกล เช่น มอดุลัสและความต้านทานต่อแรงดึง นอกจากนี้สมบัติไดอิเล็กทริกได้แสดงให้เห็นถึงการนำ ไฟฟ้าที่ความถี่ต่ำและอุณหภูมิสูง ยางที่มีหมู่อิพอกไซด์ 50 โมล% (ENR-50) มีค่าการนำไฟฟ้า และค่า permittivity สูงที่สุด ดังนั้นจึงนำยาง ENR-50 ไปใช้ในการเตรียมคอมพอสิตที่ใช้แบเรียม ไททาเนตและเขม่าดำเป็นตัวเติม ซึ่งพบว่าค่า permittivity และค่าการนำไฟฟ้าสูงขึ้นตาม ปริมาณตัวเติมที่ใส่ลงไป ที่ปริมาณ 50%โดยปริมาตรของแบเรียมไททาเนตในยางให้ค่า permittivity สูงถึง 48.7 ในขณะเดียวกันก็พบว่าการเตรียม ENR-50 คอมพอสิตที่ใช้เขม่าดำมี percolation threshold ที่ 6.3 vol% ของเขม่าดำ สำหรับการศึกษาการเปลี่ยนแปลงของสัณฐาน วิทยาและความเข้ากันได้ของพอลิเมอร์เบลนด์ระหว่างพอลิไวนิลลิดีนฟลูออไรด์ (PVDF) กับยาง ENR พบว่า สัณฐานวิทยาของพอลิเมอร์ที่เตรียมได้ขึ้นอยู่กับปริมาณหมู่อิพอกไซด์ในยาง ENR และอัตราส่วนการเบลนด์ อัตราส่วนการเบลนด์ในช่วง 40 ถึง 60% โดยน้ำหนักของยาง ENR- 50 ให้ลักษณะสัณฐานวิทยาแบบวัฏภาคร่วม (co-continuous) นอกจากนี้ผลการทดสอบจาก สมบัติพลวัตเชิงกลและสมบัติไดอิเล็กทริกแสดงให้เห็นถึงความเข้ากันได้บางส่วน (partial miscibility) ท้ายที่สุดนี้ได้เตรียมคอมพอสิตจากพอลิเมอร์เบลนด์ที่เติมแบเรียมไททาเนต สัณฐานวิทยาของคอมโพสิทที่เตรียมได้นั้น พบว่าแบเรียมไททาเนตกระจายตัวในเฟสยางเป็น หลัก อย่างไรก็ตามการเติมแบเรียมไททาเนตหลังจากการวัลคาไนซ์แบบไดนามิกส์ทำให้ แบเรียมไททาเนตกระจายตัวในเฟสพอลิไวนิลลิดีนฟลูออไรด์ (PVDF) และที่ผิวประจัญ (interface) นอกจากนี้คอมพอสิตที่เตรียมจากเทอร์โมพลาสติกวัลคาไนซ์ของ PVDF/ENR 50 ที่ อัตราส่วนการเบลนด์ที่ 80/20 ให้ค่า permittivity ที่สูง

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17

Schifferová, Zuzana. "Příprava kompozitních vláknitých struktur metodou elektrostatického zvlákňování pro piezoaplikace." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-400447.

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Polymer and composite polymer-ceramic nanofibers were prepared by electrospinning process. Solution of 20 wt.% polyvinylidene fluoride (PVDF) in a mixture of dimethyl sulfoxide (DMSO) and acetone in the ratio of 7:3 was chosen as the most suitable precursor. When preparing composite nanofibers, 20 wt.% of barium calcium zirconate titanate (BCZT) or barium titanate (BT) nanoparticles was added to this PVDF solution. Given parameters were defined as the most suitable for the process of electrospinning: voltage of 50 kV, feeding rate of 30 l/min, distance between emitter and collector of 20 cm and needle diameter of 17 G. The effect of polymer molecular weight and the rotation speed of collector was also studied. Various properties of prepared samples were studied: morphology and fiber diameter, phase composition with the use of x-ray diffraction and Fourier transform infrared spectroscopy and also chosen electrical properties. Lower fiber diameters appeared with lower polymer molecular weight and higher rotation speed of the collector. These parameters resulted in higher percentage of the piezoelectric phase as well. The smallest achieved fiber diameter was around 300 nm, the highest percentage of phase was 92 % and the highest piezoelectric constant had a value of 16 pC/N. Composite fibers filled with BT particles showed better properties that the ones filled with BCZT particles.

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18

Faleh, El Mâti el. "Les mecanismes de synthese de l'apatite par activite bacterienne : role et comportement de quelques elements mineraux, application aux phosphates sedimentaires." Strasbourg 1, 1988. http://www.theses.fr/1988STR13038.

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La synthese des apatites a ete realisee dans un milieu liquide d'eau douce ou marine, par transformation de carbonate et par precipitation directe. La cristallogenese de ces mineraux necessite une activite bacterienne indispensable a la biodegradation de la matiere organique (arn) et a la mineralisation du phosphore sous forme d'acide phosphorique. En plus de leur activite biodegradante, les bacteries servent de site a la nucleation et a la cristallisation purement chimique de l'apatite hors de leur membrane. Cette nucleation est favorisee par une forte saturation en phosphore, calcium et fluor dans un micro-milieu cree a proximite de ces micro-organismes. Les apatites synthetisees se presentent sous forme de micro-grains, constitues de cristallites enchevetres, possedant une grande surface et determinant des micropores fermes dans lesquels se piegent l'eau connee et la matiere organique. Les elements traces trouvent donc plusieurs sites possibles : insertion dans le reseau cristallin, adsorption sur la grande surface offerte par les cristallites, piegeage dans les micropores.

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19

Ramesh, Dinesh. "The Role of Interface in Crystal Growth, Energy Harvesting and Storage Applications." Thesis, University of North Texas, 2020. https://digital.library.unt.edu/ark:/67531/metadc1752367/.

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A flexible nanofibrous PVDF-BaTiO3 composite material is prepared for impact sensing and biomechanical energy harvesting applications. Dielectric polyvinylidene fluoride (PVDF) and barium titanate (BaTiO3)-PVDF nanofibrous composites were made using the electrospinning process based on a design of experiments approach. The ultrasonication process was optimized using a 2k factorial DoE approach to disperse BaTiO3 particles in PVDF solution in DMF. Scanning electron microscopy was used to characterize the microstructure of the fabricated mesh. The FT-IR and Raman analysis were carried out to investigate the crystal structure of the prepared mesh. Surface morphology contribution to the adhesive property of the composite was explained through contact angle measurements. The capacitance of the prepared PVDF- BaTiO3 nanofibrous mesh was a more than 40% increase over the pure PVDF nanofibers. A comparative study of dielectric relaxation, thermodynamics properties and impact analysis of electrospun polyvinylidene fluoride (PVDF) and 3% BaTiO3-PVDF nanofibrous composite are presented. The frequency dependent dielectric properties revealed micro structural features of the composite material. The dielectric relaxation behavior is further supported by complex impedance analysis and Nyquist plots. The temperature dependence of electric modulus shows Arrhenius type behavior. The observed non-Debye dielectric relaxation in electric loss modulus follows a thermally activated process which can be attributed to a small polaron hopping effect. The particle induced crystallization is supported with thermodynamic properties from differential scanning calorimetric (DSC) measurements. The observed increase in piezoelectric response by impact analysis was attributed to the interfacial interaction between PVDF and BaTiO3. The interfacial polarization between PVDF and BaTiO3 was studied using density functional theory calculations and atomic charge density analysis. The results obtained indicates that electrospinning offers a potential way to produce nanofibers with desired crystalline nature which was not observed in molded samples. In addition, BaTiO3 can be used to increase the capacitance, desired surface characteristics of the PVDF nanofibers which can find potential application as flexible piezoelectric sensor mimicking biological skin for use in impact sensing and energy harvesting applications.

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Cherqaoui, Bennaceur. "Etude du comportement rhéologique à l'état fondu et du comportement diélectrique du polyfluorure de vinylidène chargé de titanate de baryum." Saint-Etienne, 1986. http://www.theses.fr/1986STET4007.

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Etude en régime dynamique et en régime statique. L'addition de titanate augmente la constante diélectrique tout en gardant un niveau faible des pertes diélectriques. Essais d'extrusion difficiles compte tenu des temps de relaxation et viscosité élevées de la matrice

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21

Aulagner, Emmanuel. "Elaboration et étude des propriétés diélectriques de films minces de polyfluorure de vinylidène et de polypropylène chargés d'une céramique à haute permittivité relative." Saint-Etienne, 1996. http://www.theses.fr/1996STET4002.

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Des films de polyfluorure de vinylidène et de polypropylène, chargés en titanate de baryum, sont réalisés par extrusion. Les propriétés diélectriques de ces films sont mesurées dans différentes conditions. Les films à matrice PVDF présentent les meilleures caractéristiques pour une application de stockage d'énergie. L'évolution de la permittivité relative et de la rigidité diélectrique en fonction du taux volumique de charge, sont modélisées respectivement par la théorie de la percolation et par un modèle semi-empirique. Les mélanges sont étudiés en rhéométrie dynamique et capillaire. Les interactions interparticules donnent naissance à un réseau dont la structure est dépendante de la sollicitation appliquée. En écoulement de poiseuille, des instabilités d'écoulement ainsi que des défauts d'écoulement sont observés pour des gradients de vitesse de cisaillement relativement faibles

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22

Militon, Christian. "La metallogenie polyphasee a zn-pb-ba-f et mg-fe de la region de gedre-gavarnie-barroude (hautes-pyrenees)." Orléans, 1987. https://tel.archives-ouvertes.fr/tel-00798146.

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Une prospection geologique systematique de ces terrains a conduit a la reconnaissance de quatre principaux types de mineralisations dans le socle, le devonien inferieur et le cretace : 1 - une mineralisation stratiforme a zn-pb-ba-f de type sedimentaire - exhalatif omnipresente au sommet de la barre calcaire emsienne (devonien inferieur). 2 - de nombreux filons de types b. P. G. C. A gangue de siderite avec, pour certains, presence importante de barytine ou de fluorine ; ces filons correspondent a une phase de mineralisation tardi-hercynienne, probablement en liaison avec une phase tectonique compressive impliquant un contexte decrochant a composante cisaillante senestre, evoluant progressivement vers une distension nord-sud. 3 - des amas metasomatiques a mg-fe dans la barre calcaire emsienne, pouvant representer le sommet du systeme hydrothermal responsable des filons tardi-hercyniens du socle. 4 - la dissemination de galene dans les calcaires du santonien et de petits amas decimetriques de barytine secants sur la dolomie greseuse du cenomanien ; ces indices traduisent la remobilisation de filons tardi-hercyniens principalement d'apres l'identite des compositions isotopiques du plomb.

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王福堂. "Dielectric Study of Barium Titanate Mixed with Barium Fluoride Thin Films Fabricated by R. F. Sputtering." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/03055308799146459682.

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碩士
輔仁大學
物理學研究所
86
The main goal of this study, we deposited Barium Titanate mixed with Fluoride thin film by R.F.- Sputtering. The main of mixture is Barium Fluoride ( BaF2 ). The synthesis of Barium Titanate ( BaTiO3 ) ceramic fabricated by solid-state reaction process. The composition of the ceramic is Barium Carbonate (BaCO3) and Titanium Dioxide (TiO2) and Barium Fluoride The ceramic is used for the target on the sputtering. Titanium is used for electrode. We develop the MIM ( metal - insulator - metal ) structure for producing Barium Titanate thin film capacitor. The parameters of processing include : Oxygen content and temperature. The capacitors were also analyzed by X-ray diffraction, Ellipsometry, scanning electron microscopy, P - E Curve, etc.

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24

Kurz, Volker. "Magneto-optical measurements on niobium selenide, barium fluoride and gallium arsenide." 2007. http://proquest.umi.com/pqdweb?did=1441230031&sid=3&Fmt=2&clientId=39334&RQT=309&VName=PQD.

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Thesis (M.S.)--State University of New York at Buffalo, 2007.
Title from PDF title page (viewed on June 17, 2008) Available through UMI ProQuest Digital Dissertations. Thesis adviser: Cerne, John. Includes bibliographical references.

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Hsien, Cheng Chih, and 鄭至先. "The Effect of Lithium Fluoride and Borosilicate Glass on the sintering and Dielectric Properties of Barium Titanate." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/85606358427280101932.

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碩士
國立臺灣大學
材料科學與工程學研究所
90
In the present study, two liquid-phase sintering aids, lithium fluoride (LiF) and a borosilicate glass were added into barium titanate to reduce its sintering temperature. The Ba/Ti ratio of the BaTiO3 powder was either higher or lower than unity. The effects of the liquid-phase sintering aids on the sintering behavior and dielectric properties of the BaTiO3 were investigated. The densification rate of barium titanate was significantly enhanced as the sintering temperature was raised above 842℃, the melting point of LiF. When the Ba/Ti ratio was higher than unity, the densification rates was much higher than that of the powder small Ba/Ti ratio. The addition of the borosilicate glass could also lower the sintering temperature of BaTiO3. However, the borosilicate glass reacted with BaTiO3 to form BaTiSiO5, Ba2TiSi2O8, BaTiSi3O9 and BaTi(BO3)2. The dielectric constant of the reaction phases was low so that dielectric property of sintered BaTiO3 was thus degraded.

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Mehner, Erik. "Pyroelektrische Materialien: elektrisch induzierte Phasenumwandlungen, thermisch stimulierte Radikalerzeugung." Doctoral thesis, 2017. https://tubaf.qucosa.de/id/qucosa%3A31917.

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Zur Messung pyrelektrischer Koeffzienten wurde ein Messplatz nach einem erweiterten SHARP-GARN-Verfahren entwickelt und zur Untersuchung von Phasenumwandlungen in Pyroelektrika eingesetzt. Einerseits konnten pyroelektrische Messungen im elektrischen Feld die Pyroelektrizität einer neuen durch elektrisch angetriebene Defektmigration erzeugten Phase in Strontiumtitanat nachweisen. Andererseits gelang es, Ferroelektrizität in der Hochtemperaturphase von Poly(Vinylidenfluorid-Trifluorethylen), mittels phasenreiner Präparation der Hochtemperaturphase unterhalb der CURIEtemperatur und anschließender Polarisierung, nachzuweisen. Ferner ließen sich mittels thermisch angeregter Pyroelektrika Redoxprozesse antreiben, was durch Desinfektion von Escherichia coli Bakterien in wässriger Lösung mittels Lithiumniobat und -tantalat gezeigt wurde. Die Hypothese der Desinfektion durch reaktive Sauerstoffspezies konnte durch spektroskopisch nachgewiesene OH-Radikale - erzeugt mittels thermisch angeregter Bariumtitanatnanopartikel - belegt werden.

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