Utilisés pour leur bon compromis entre propriétés mécaniques, thermiques et électriques, les alliages Cu-Ni-Si à durcissement structural par précipitation sont notamment employés pour la maintenance ferroviaire. Ils sont donc soumis aux passages des trains et aux effets d’environnement. C’est pourquoi la résistance d’un alliage CuNi2Si a été étudiée en fatigue oligocyclique, en corrosion aqueuse et en fatigue-corrosion. Le but est de relier les propriétés macroscopiques aux mécanismes microstructuraux. Les essais de fatigue ont montré un durcissement initial de l’alliage, suivi d’un adoucissement continu jusqu’à la rupture. À l’aide des microscopies électroniques en transmission (MET) et à balayage (MEB), notamment en ECCI (Electron Channeling Contrast Imaging) et en EBSD (Electron BackScattered Diffraction), une formation initiale de cellules de dislocations a été identifiée, ces dernières disparaissant au profil de la formation de bandes dénuées de précipités suite à la dissolution mécanique des précipités δ-Ni2Si. Ceci constitue le mécanisme d’accommodation de la déformation cyclique. L’avancée de la formation de ces bandes explique les différents régimes observés sur le diagramme de Manson-Coffin. L’alliage présente en milieu NaCl à 50 g.L1 un mécanisme de corrosion intergranulaire. La spectroscopie d’impédance électrochimique (SIE) semble indiquer la présente d’un film passif compact en surface de l’alliage. Enfin, une sensibilité à la fatigue-corrosion apparaît, notamment aux plus hauts niveaux de déformation où la durée de vie est réduite d’un tiers. De plus, un faciès de rupture semblable à ceux observés en corrosion sous contrainte est constaté. / Employed for their good balance between mechanical, thermal and electrical properties, precipitation hardened Cu-Ni-Si alloys are used for various purposes, including railway maintenance. In the latter case, they are submitted to train traffic and environmental effects. This is why the low cycle fatigue (LCF), the wet corrosion and the fatigue-corrosion behaviours of a CuNi2Si alloy have been studied. The aim of the present work is to relate the macroscopic properties to the microstructural behaviour. The fatigue life of the alloy is composed of an initial hardening step, followed by a continuous softening until fracture. Thanks to the combination of transmission and scanning electron microscopies (respectively TEM and SEM), including ECCI (Electron Channeling Contrast Imaging) in addition to EBSD (Electron BackScattered Diffraction), the formation of dislocation cells has been identified, which ones are then consumed by the formation of precipitate free bands after the mechanical dissolution of the δ-Ni2Si precipitates. This sequence describes the cyclic strain accommodation mechanism. The progress in the formation of these bands explains the different regimes observed into the Manson-Coffin diagram. The alloy exhibits intergranular corrosion in 50 g.L-1 NaCl solution. The electrochemical impedance spectroscopy (EIS) indicates the formation of a compact passive film at the surface of the alloy. Finally, the alloy seems to be sensible to fatigue-corrosion, especially at high strain range where the number of cycle to failure is reduced by a third. Moreover, a fracture surface similar to a stress corrosion cracking surface is also observed.

Organic semiconductor interfaces are promising materials for use in next-generation electronic and optoelectronic devices. Current models for metal-organic interfacial electronic structure and dynamics are inadequate for strongly hybridized systems. This work aims to address this issue by identifying the factors most important for understanding chemisorbed interfaces with an eye towards tuning the interfacial properties. Here, I present the results of my research on chemisorbed interfaces formed between thin-films of phthalocyanine molecules grown on monocrystalline Cu(110). Using atomically-resolved nanoscale imaging in combination with surface-sensitive photoemission techniques, I show that single-molecule level interactions control the structural and electronic properties of the interface. I then demonstrate that surface modifications aimed at controlling interfacial interactions are an effective way to tailor the physical and electronic structure of the interface. This dissertation details a systematic investigation of the effect of molecular and surface functionalization on interfacial interactions. To understand the role of molecular structure, two types of phthalocyanine (Pc) molecules are studied: non-planar, dipolar molecules (TiOPc), and planar, non-polar molecules (H2Pc and CuPc). Multiple adsorption configurations for TiOPc lead to configuration-dependent self-assembly, Kondo screening, and electronic energy-level alignment. To understand the role of surface structure, the Cu(110) surface is textured and passivated by oxygen chemisorption prior to molecular deposition, which gives control over thin-film growth and interfacial electronic structure in H2Pc and CuPc films. Overall, the work presented here demonstrates a method for understanding interfacial electronic structure of strongly hybridized interfaces, an important first step towards developing more robust models for metal-organic interfaces, and reliable, predictive tuning of interfacial properties.

In this work, the possibility of Cu electrodeposition on Ru-Ta alloy thin films is explored. Ru and Ta were sputter deposited on Si substrate with different composition verified by RBS. Four point probe, XRD, TEM and AFM were used to study the properties of Ru-Ta thin films such as sheet resistance, crystallinity, grain size, etc. Cyclic voltammetry is used to study the Cu electrodeposition characteristics on Ru-Ta after various surface pretreatments. The results provide insights on the removal of Ta oxide such that it enables better Cu nucleation and adhesion. Bimetallic corrosion of Cu on modified Ru-Ta surface was studied in CMP related chemicals. In Cu interconnect fabrication process, the making of trenches and vias on low-k dielectric films involves the application of fluorocarbon plasma etch gases. Cu microdots deposited on Ru and Ta substrate were treated by fluorocarbon plasma etch gases such as CF4, CF4+O2, CH2F2, C4F8 and SF6 and investigated by using x-ray photoelectron spectroscopy, contact angle measurement and electrochemical techniques. Micropattern corrosion screening technique was used to measure the corrosion rate of plasma treated Cu. XPS results revealed different surface chemistry on Cu after treating with plasma etching. The fluorine/carbon ratio of the etching gases results in different extent of fluorocarbon polymer residues and affects the cleaning efficiency and Cu corrosion trends.

京都大学 / 新制・課程博士 / 博士(理学) / 甲第23029号 / 理博第4706号 / 新制||理||1675(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)准教授 加納 太一, 教授 依光 英樹, 教授 時任 宣博 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

The Cassenha Hill copper-gold prospect is situated in the Catabola area, Huambo Province, southwestern Angola. Geologically, the prospect is part of the Angolan Central Eburnean Zone (CEZ) and consists of Paleoproterozoic metasedimentary rock sequences which have been intruded by Eburnean granitoids at ± 2.1 Ga. The prospect itself comprises an area of 180 Km2 and has been intermittently explored since 2005 by Rift Valley Resources (RVR) and its associates. The Cassenha Hill prospect is characterized by the occurrence of partially altered and highly oxidized metasedimentary rocks (meta-mudstone, meta-siltstone, carbonate-rich rock, meta-sandstone, breccia, and quartzite), and altered isolated granitoids. This study represents the first detailed study of the prospect and aims to shed light on the characteristics of the various rock types (i.e., host and barren rocks), their source/provenance, styles of alteration, and the origin and/or type of the fluid responsible for the mineralization. Techniques applied include borehole core logging, petrography, whole-rock geochemistry (XRF and ICP-MS), and stable isotope geochemistry on samples collected on the surface and from exploration boreholes drilled as part of RVR exploration program. Overall, the petrographic and geochemical studies undertaken in the rocks of the Cassenha Hill prospect indicate the following: (1) The rocks are moderately to strongly fractured; (2) The rocks have experienced weak to moderate chemical weathering; (3) The rocks are compositionally immature and originated from felsic provenance; (4) The rocks are sulfur-poor, and lacking in sulfide minerals (5) The rocks are enriched in LREE and LILE elements and depleted in HREE and HFSE elements; (6) The mineralization is associated with chloritization alteration and predominantly occurs within and/or at the edges of quartz/chlorite-rich veins/fractures and is not restricted to any rock type. Two ore stages could be identified, namely, hypogene ore (stage I) consisting of pyrite ± chalcopyrite ± other copper sulfides, and supergene ore (stage II) consisting of malachite ± azurite ± chrysocolla, which represents the prevalent mineralization at the prospect. The δ 18O value of quartz veins range from +12.81 to +13.53‰, while the δD of chlorite minerals range from -51 to -45‰. Therefore, assuming fluid-rock interaction took place at ≈ 350oC, due to the presence of quartz, the fluid had δ 18OH20 values of about +8‰, which are typical of magmatic waters. On the other hand, at a temperature of ≈ 350oC, and with the difference between chlorite and water being -33.5‰, such fluids would have had δDH20 values of about -20‰ (δ 18OH20= -4‰), which are typical of meteoric waters. Although the various mineral phases have yielded different isotopic signatures, this study suggests that water is ultimately of meteoric origin but exchanged with hydrogen-poor magmatic rock, thus maintaining the meteoric signature. The continuous influx of meteoric waters within the fracture system led to the development of copper oxides such as malachite, azurite and chrysocolla, which possibly originated from the insitu oxidation of the hypogene sulfides. This signature, together with other field, petrographic and geochemical observations allows one to, tentatively, suggest that the Cassenha Hill prospect represents an extension of a polymetallic vein-type of porphyry Cu deposit that has been subjected to supergene processes at the weathering profile.

Title: Electronics and adsorption properties of model catalytic systems contains cerium Author: Miloš Cabala Department: Department of Surface and Plasma Science, Supervisor: RNDr. Kateřina Veltruská, Department of Surface and Plasma Science, Abstract: The doctoral thesis contains the study of model catalyst systems based on cerium and ceria. The thesis deals with model systems of CeAg, CeO2/Cu(111), Ni- CeO2/Cu(111) a Ni-Sn-CeO2/Cu(111). We have studied these systems using photoelectron spectroscopy, ion scattering spectroscopy and low energy electron diffraction. Model systems were prepared under strictly defined conditions. The strong bimetallic interaction was observed on the CeAg layers. Molecular adsorption of carbon monoxide on CeAg was demonstrated. We also observed intensive reaction of these layers with oxygen. By measurements in different directions of surface Brillouin zone, we managed to reconstruct the band structure of the prepared CeO2/Cu(111) layer. We have shown that the Cu substrate interacts weakly with deposited CeO2 layer. This interaction results in a charge transfer from Cu into CeO2. Overall, in the valence spectrum we have identified three main electron bands corresponding to O 2p state bound in CeO2. It has been proven that the deposition of Ni on CeO2 layers leads to partial...

Die Cu – Ag - Mikroverbund – Werkstoffe besitzen das Potenzial die gegensätzlichen Anforderungen an das Leitermaterial für den Einsatz in einem Hochfeldmagneten, wie hohe Festigkeit bei gleichzeitig hoher elektrischen Leitfähigkeit und ausreichender Verformbarkeit, zu erfüllen. Außerdem bieten diese Werkstoffe gegenüber den anderen, die dafür in Frage kommen können, den großen technologischen Vorteil einer konventionellen schmelzmetallurgischen Herstellung. Jedoch wurde bisher dafür eine sehr aufwändige Technologie verwendet, die die Herstellung des Leitermaterials nur im Labormaßstab ermöglicht. Die vorliegende Arbeit befasst sich mit einer Technologie der Herstellung von Leitern, die den Anforderungen für den Einsatz in einem Hochfeldmagneten genügen können und in einem großtechnischen Maßstab verfügbar sind. Der Schwerpunkt der Leiterherstellung aus Cu – Ag - Legierung lag in der Einstellung der geeigneten Mikrostruktur über metallkundliche Mechanismen vor der Drahterzeugung. Hierfür wurden während der einzelnen Prozessschritten die Gefügeentwicklung und für die Anwendung relevante Eigenschaften der Legierungen in binären Cu – Ag – Legierungen und in ternären Cu – Ag -X –Legierungen untersucht. Darüber hinaus wurde der Einfluss der Mikrostruktur und der Zusammensetzung auf die mechanischen und elektrischen Eigenschaften der Drähte ermittelt sowie eine Korrelation zwischen Mikrostruktur und elektrischen Eigenschaften aufgestellt.

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With high rates of cannabis use in college students and increasing legalization of cannabis, psychometrically sound scales of cannabis consumption remain a high research priority. The Daily Sessions, Frequency, Age of Onset, and Quantity of Cannabis Use Inventory (DFAQ-CU; Cuttler & Spradlin, 2017) assesses daily sessions, frequency, age of onset, and quantity of marijuana, concentrates, and edibles consumed. Preliminary psychometric properties have been established in a population of college students using cannabis legally. The current study aims to evaluate the psychometric properties of the DFAQ-CU in college students using cannabis illicitly. Participants (N=114) were 18- to 58-years-old (M=21.25). They completed the DFAQ-CU, Drug Use Disorders Identification Test (DUDIT), and Buss Perry Aggression Questionnaire (BPAQ). Analyses were performed using the original factor structures. The factor analysis will be replicated once the full sample has been obtained (~400 by 02/2021). Cronbach's alphas ranged from.32 to.92, with some factors showing stronger reliability (e.g., frequency) than others (e.g., daily sessions). Bivariate correlations indicated daily sessions (r(54)=.32, p=.02), frequency (r(53)=.50, p<.001), marijuana quantity (r(78)=.32, p=.004), and edible (r(25)=.54, p=.006) factors demonstrated high convergent validity with the DUDIT total score. The age of onset and concentrate quantity factors did not. All factors were significantly divergent from the BPAQ. Overall, the original six-factor scale appears to have a poor fit within a college student population with illicit use. Notably, the concentrate quantity and daily sessions factors have poor internal consistency and convergent validity. These will be further explored upon completion of data collection.

No description available.