Search results for: S. Wiesner

Items from 1 to 20 out of 31 results

article

Microstructural analysis of germanium modified tin‐copper brazing filler metals for transient liquid phase bonding of aluminium

R. Iskandar, A. Schwedt, J. Mayer, P. Rochala, more

Materialwissenschaft und Werkstofftechnik > 48 > 12 > 1257 - 1263

The present contribution summarises first results that have been achieved with the new brazing material Sn75Cu20Ge5 (wt‐%) for transient liquid phase (TLP) bonding of aluminium cast alloy AlSi7Mg0.3 (wt‐%). The microstructure of the braze ribbons and the obtained joints have been thoroughly investigated on different length‐scales using scanning and transmission electron microscopy as well. Whereas...

article

Formation of the reaction zone between tin‐copper brazing fillers and aluminum‐silicon‐magnesium alloys: Experiments and thermodynamic analysis

K. Bobzin, M. Öte, S. Wiesner, A. Schmidt, more

Materialwissenschaft und Werkstofftechnik > 48 > 12 > 1241 - 1248

A primary challenge in brazing is the controlled formation of phases resulting from interactions of elements of the liquid filler metal with those of the base material. The morphology of the brazed joint, which is decisive for the mechanical properties of the joint, is influenced by present elements and process parameters such as brazing temperature and time. Furthermore, the wetting of the base material...

article

Residual stress measurement in AlSi alloys

U. Reisgen, R. Sharma, S. Gach, S. Olschok, more

Materialwissenschaft und Werkstofftechnik > 48 > 12 > 1270 - 1275

In this work, the relaxation of residual stresses inside a sample made of the aluminum alloy AlSi7Mg0.3 after tempering is described. The comparison of stress evaluation by X‐ray diffraction and incremental hole drilling method combined with electronic speckle pattern interferometry strain determination gives the opportunity to evaluate micro stresses together with first order macro stresses. Compressive...

article

Effect of Alloying Elements on Growth Behavior of Intermetallic Compounds at the Cold-Sprayed Coating/Steel Interface During Immersion in Aluminum Melt

K. Bobzin, M. Öte, S. Wiesner, L. Gerdt, more

International Journal of Metalcasting > 2018 > 12 > 4 > 712-721

The formation of the intermetallic compounds at the interface between cold-sprayed coatings and steel as well as interaction between coatings and aluminum melt was investigated. Coatings of AA7075 (AlZn5.5MgCu) and AA4145 (AlSi10Cu4) were deposited on the sheets of the deep drawing steel DC04. The coated samples were then immersed in the aluminum melt AlSi9Mn at the temperature of T = 610 °C for different...

article

CuInSe2 nanostructures prepared by chemical close-spaced vapor transport for hybrid photovoltaic devices

S. Vatavu, N. von Morzé, S. Wiesner, S. Moras, more

Thin Solid Films > 2017 > 633 > C > 185-192

This work focuses on the fabrication of stoichiometric CuInSe₂ nanostructures with controllable physical parameters of the nanocrystals suitable for hybrid organic/inorganic photovoltaics. CuInSe₂ nanostructures were prepared by the chemical close-spaced vapor transport (CCSVT) method onto Mo/barrier/glass substrates by using an In₂Se₃ source material and Cu precursors. The In₂Se₃ source material...

article

Impact of the CaCl2 content in the rehydration media on the microcapsule formation out of spray dried capsule precursors for the immobilization of probiotic bacteria

R. Würth, S. Wiesner, P. Foerst, U. Kulozik

International Dairy Journal > 2017 > 68 > C > 75-79

The aim of this work was to develop a capsule formation process at moderate temperatures with a high encapsulation yield (EY) of probiotic bacteria. Capsule precursors (CP) obtained by spray drying were rehydrated at 40 °C in aqueous solution to form water-insoluble hydrogel capsules. The CaCl₂ concentration (0–2 mm) in the rehydration solution was varied. The rehydration step was evaluated regarding...

article

An immunocompetent 49-year-old man with a disseminated infection

S. Ortiz, S. Wiesner, J.C. Cataño

European Journal of Internal Medicine > 2016 > 34 > C > e5-e6

•Nowadays, paracoccidioidomycosis can be seen anywhere in the world•Paracoccidioidomycosis clinical manifestations can be very diverse•Paracoccidioidomycosis diagnosis often requires deep tissue biopsies•Metastatic malignancies has to be ruled out when suspecting Paracoccidioidomycosis

article

X-ray irradiation induced effects on the chemical and electronic properties of MoO3 thin films

X. Liao, A.R. Jeong, R.G. Wilks, S. Wiesner, more

Journal of Electron Spectroscopy and Related Phenomena > 2016 > 212 > C > 50-55

The time and photon-flux dependent x-ray irradiation induced effects on the chemical and electronic properties of MoO₃ thin films have been systematically investigated by ultraviolet photoelectron spectroscopy (UPS) and x-ray photoelectron spectroscopy (XPS). After exposure to Mg K_α x-ray irradiation of different photon flux (realized by using different x-ray source powers: 30, 100, and 300W), the...

chapter

Performance and Transport Properties of Phthalocyanine:Fullerene Organic Solar Cells

M. Rusu, J. Gasiorowski, S. Wiesner, D. Keiper, more

Springer Proceedings in Physics > Interface Controlled Organic Thin Films > E. Organic Devices > 195-198

Copper phthalocyanine (CuPc)-fullerene (C₆₀) photovoltaic cells are produced by organic vapour phase deposition reaching efficiencies of 3%. The electronic transport properties of the devices are investigated as a function of the CuPc:C₆₀ absorber blend layer composition and its preparation temperature. The analysis of the transport properties of the devices employs the one-diode model. It is shown...

article

Erforschung Ti–Co‐basierter, bioaktiver Auftraglötschichten auf oxidischen Hochleistungskeramiken in der Medizintechnik

K. Bobzin, N. Kopp, S. Wiesner, S. Puidokas, more

Materialwissenschaft und Werkstofftechnik > 45 > 6 > 504 - 504

Der Bedarf an Prothesen und Implantaten aus Biomaterialien nimmt infolge des steigenden Menschenalters stetig zu. Bei Biomaterialien, z. B. bei Hüft‐ oder Gelenkprothesen, die im direkten Kontakt mit dem Organismus stehen, wird nicht nur die mechanische Belastbarkeit gefordert, sondern auch die Verträglichkeit der Substanzen im Körper sowie die Fähigkeit zum Knochenaufbau. Um dies zu ermöglichen,...

article

Optical constants of diindenoperylene in the dependence of preparation temperature and pressure

D. Greiner, V. Hinrichs, S. Wiesner, W. Ludwig, more

Thin Solid Films > 2013 > 534 > Complete > 255-259

We determine the optical constants, that is, refractive index n, extinction coefficient k, and absorption coefficient α, of diindenoperylene (DIP) films deposited by organic vapor phase deposition (OVPD®) on quartz glass at different substrate temperatures between 60°C and 140°C and chamber pressures between 0.08 and 1.10kPa. The corresponding optical properties of the OVPD-films are compared with...

article

Stable Organic Solar Cells with Mg:Ag Contacts

M. Rusu, F. Kraffert, S. Wiesner, W. Schindler, more

Energy Procedia > 2012 > 31 > Complete > 96-101

Stable and efficient organic solar cells with Mg (20 at. %): Ag alloy cathodes and bulk-heterojunction absorber layers from metal (e.g., Cu, Zn)-phthalocyanine and C60 small molecules are demonstrated. Device efficiencies of 4.0% under an illumination of 100 mW/cm2 at 25̊C were achieved as a result of the fine adjustment of the cathode work function as well as of the absorber design. By combining...

article

CuGaxSey chalcopyrite-related thin films grown by chemical close-spaced vapor transport (CCSVT) for photovoltaic application: Surface- and bulk material properties, oxidation and surface Ge-doping

M. Rusu, S. Wiesner, R. Würz, S. Lehmann, more

Solar Energy Materials and Solar Cells > 2011 > 95 > 6 > 1555-1580

Device-grade ternary Cu–Ga–Se chalcopyrite thin films used for photovoltaic energy conversion have been prepared by a novel chemical close-spaced vapor transport (CCSVT) technique developed for a deposition on areas of up to 10×10cm ² . A two-step process has been developed which allows the fine tuning of the film composition and the electronic properties. The extension of deposition times...

article

Research Supplement

C. S. Wiesner

Welding in the World > 2009 > 53 > 1-2 > R1-R1

article

Fine tailored interpenetrating donor–acceptor morphology by OVPD for organic solar cells

M. Rusu, J. Gasiorowski, S. Wiesner, N. Meyer, more

Thin Solid Films > 2008 > 516 > 20 > 7160-7166

The fine adjustment of the organic absorber nanoscopic properties, such as crystallite orientation, dimension and separation distance is demonstrated. This is essential for organic solar cells based on bulk and three-layered molecular heterojunctions for well controlled and reproducible properties. The required structures are achieved by using the organic vapor-phase deposition technique. Homogeneously...

article

Organic donor, acceptor and buffer layers of small molecules prepared by OVPD technique for photovoltaics

M. Rusu, S. Wiesner, T. Mete, H. Blei, more

Renewable Energy > 2008 > 33 > 2 > 254-258

Organic vapour-phase deposition (OVPD ^® ) is used for the growth of the organic solar cell component materials such as the donor copper phthalocyanine (CuPc), the acceptor fullerene C ₆₀ , and electron-conducting buffer layers of bathocuproine (BCP) on Si〈100〉 wafers and indium tin oxide (ITO) substrates on areas as large as 15×15cm ² . By means of X-ray diffraction (XRD) analysis...

article

Research Supplement

Christoph S. Wiesner

Welding in the World > 2008 > 52 > 11-12 > 9-9

article

Recent Developments in the Friction Stir Welding of Titanium Alloys

M. J. Russell, C. Blignault, N. L. Horrex, C. S. Wiesner

Welding in the World > 2008 > 52 > 9-10 > 12-15

This paper describes recent developments in the joining of titanium alloys using Friction Stir Welding (FSW). Titanium alloys represent an extremely challenging application for FSW, due to their high strength, high melting point, and very low thermal conductivity. Recent work at TWI has resulted in the invention of a new variant of FSW, named Stationary Shoulder Friction Stir Welding (SSFSW), which...

chapter

Monitoring Patient Respiration using a Single Optical Camera

S. Wiesner, Z. Yaniv

2007 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society > 2740 - 2743

29th Annual International Conference of the IEEE EMBS

We present a system for monitoring patient respiration using a single low cost camera. The system is based on tracking the motion of color fiducials placed on the patients abdomen. We show that our system is able to deal with variations in camera pose, and that its performance is equivalent to that obtained when using a commercial tracking system. We also validate our system using ultrasound images...

article

CuGaSe2–CuGa3Se5 phase transition in CCSVT-grown thin films

S. Lehmann, M. Bär, D. Fuertes Marrón, P. Pistor, more

Thin Solid Films > 2006 > 511-512 > Complete > 623-627

The system CuGaSe ₂ –CuGa ₃ Se ₅ in thin films has been investigated. Layer synthesis was carried out by chemical close-spaced vapour transport (CCSVT) using Cu precursors on Mo/soda-lime glass substrates. The extension of deposition times in a two-step process led to final film compositions with [Ga]/[Cu] ratios ranging from 1 to 3, allowing the study of the phase transition...

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Search results for: S. Wiesner

Microstructural analysis of germanium modified tin‐copper brazing filler metals for transient liquid phase bonding of aluminium

Formation of the reaction zone between tin‐copper brazing fillers and aluminum‐silicon‐magnesium alloys: Experiments and thermodynamic analysis

Residual stress measurement in AlSi alloys

Effect of Alloying Elements on Growth Behavior of Intermetallic Compounds at the Cold-Sprayed Coating/Steel Interface During Immersion in Aluminum Melt

CuInSe2 nanostructures prepared by chemical close-spaced vapor transport for hybrid photovoltaic devices

Impact of the CaCl2 content in the rehydration media on the microcapsule formation out of spray dried capsule precursors for the immobilization of probiotic bacteria

An immunocompetent 49-year-old man with a disseminated infection

X-ray irradiation induced effects on the chemical and electronic properties of MoO3 thin films

Performance and Transport Properties of Phthalocyanine:Fullerene Organic Solar Cells

Erforschung Ti–Co‐basierter, bioaktiver Auftraglötschichten auf oxidischen Hochleistungskeramiken in der Medizintechnik

Optical constants of diindenoperylene in the dependence of preparation temperature and pressure

Stable Organic Solar Cells with Mg:Ag Contacts

CuGaxSey chalcopyrite-related thin films grown by chemical close-spaced vapor transport (CCSVT) for photovoltaic application: Surface- and bulk material properties, oxidation and surface Ge-doping

Research Supplement

Fine tailored interpenetrating donor–acceptor morphology by OVPD for organic solar cells

Organic donor, acceptor and buffer layers of small molecules prepared by OVPD technique for photovoltaics

Research Supplement

Recent Developments in the Friction Stir Welding of Titanium Alloys

Monitoring Patient Respiration using a Single Optical Camera

CuGaSe2–CuGa3Se5 phase transition in CCSVT-grown thin films

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