Recently it has been discovered that when growing AlxGa1−xN on low-defect-density bulk AlN substrates pseudomorphic layers can be achieved with a thickness far exceeding the critical thickness as given by the Matthews and Blakeslee model. For instance, the critical thickness of an AlxGa1−xN layer (with x=0.6) is about 40 nm thick. However we have been able to grow layers with this composition that are pseudomorphic with a thickness exceeding the critical thickness by more than an order of magnitude. This work defines the limits of pseudomorphic growth on low defect density, bulk AlN substrates to obtain low defect density, high-power UV LEDs. 相似文献
Polymers with pendant phenoxyl radicals are synthesized and the electrochemical properties are investigated in detail. The monomers are polymerized using ring‐opening metathesis polymerization (ROMP) or free‐radical polymerization methods. The monomers and polymers, respectively, are oxidized to the radical either before or after the polymerization. These phenoxyl radicals containing polymers reveal a reversible redox behavior at a potential of −0.6 V (vs Ag/AgCl). Such materials can be used as anode‐active material in organic radical batteries (ORBs).
Summary: The influence of architecture on ink‐jet printability of polymer solutions is investigated by comparing linear and 6‐arm star PMMA. At comparable concentration and molecular weight, filament formation is much more pronounced for linear PMMA than for star PMMA. Visual examination of filament stretching allows estimation of the involved elongation rates, which are at high voltages sufficiently large for coil‐stretch transition of the chains, suggesting its role in filament formation.
The results obtained in this study suggest a possible role of the coil‐stretch transition of the polymer chains in filament formation. 相似文献
Zusammenfassung An Hand neuer Versuche wird unter Berücksichtigung der vorliegenden Literatur die Anwendung der quantitativen Spektralanalyse auf die Bestimmung von Blei in Blut diskutiert.Es wird eine Methode beschrieben, welche die quantitative spektralanalytische Bestimmung eines Blutbleigehaltes bis zu 0,1mg in 100ccm Blut gestattet.Zur Verbindung der chemischen Voranalyse mit der Spektralanalyse wird die elektrolytische kathodische Bleifällung als Metall angewandt.Die Fehlerquellen der Spektralanalyse, sowie der Elektrolyse, verhindern vorläufig eine Steigerung der Empfindlichkeit und werden einer eingehenden kritischen Betrachtung unterzogen.Wir sind der Notgemeinschaft der Deutschen Wissenschaft und dem Reichsinnenministerium, welche die vorliegenden Untersuchungen ermöglichten, zu besonderem Dank verpflichtet. Aufrichtiger Dank gilt Herrn Prof. Dr. Th. v. Wasielewski, Rostock, der uns ihre Ausführung übertrug und sie in zuvorkommender Weise förderte. Einen großen Teil der experimentellen Arbeiten führte Herr Dr. H. Starck, Rostock, unter der Instituts-Leitung von Herrn Prof. Dr. Kollath, Rostock, aus, wofür wir auch an dieser Stelle herzlichst danken möchten. 相似文献
Ionic liquid gels, or ionogels, are semi‐conductive, flexible materials, offering a host of tunable physical properties, gaining an increasing level of scientific interest. One of the challenges of this emerging category of materials is that the structure–process–property relationships are still empirically driven. In this study, a simple, practical approach is laid out to prepare standardized libraries of these materials, for the purpose of selecting transparent, flexible conductive formulations that can be dispensed using inkjet printing. The net result of this was the optimization of a PEG‐DMA ionogel formulation exhibiting an optical transparency that was greater than 94% from near‐UV to near‐IR from a 150 µm thick films, and a resistivity of 12.4 Ω · m.
