@inproceedings{GuizzardiWagnerSinderen, author = {Guizzardi, Giancarlo and Wagner, Gerd and Sinderen, Marten van}, title = {A Formal Theory of Conceptual Modeling Universals}, editor = {B{\"u}chel, Gregor and Klein, Bertin}, language = {en} } @inproceedings{Wagner, author = {Wagner, Gerd}, title = {A UML Profile for External Agent-Object Relationship Models}, language = {en} } @incollection{Wagner, author = {Wagner, Gerd}, title = {Web Rules Need Two Kinds of Negation}, language = {en} } @misc{TaveterWagner, author = {Taveter, Kuldar and Wagner, Gerd}, title = {Agent-Oriented Enterprise Modeling Based on Business Rules}, language = {de} } @inproceedings{Wagner, author = {Wagner, Gerd}, title = {A Database needs two knds of Negation}, language = {en} } @misc{SchmeisserIrmscherWagner, author = {Schmeißer, Dieter and Irmscher, Klaus and Wagner, Gerd}, title = {Photoelectron spectra of Al dopants in 4H-SiC}, series = {Materials Science \& Engineering B}, volume = {102}, journal = {Materials Science \& Engineering B}, number = {1-3}, issn = {0921-5107}, pages = {284 -- 288}, abstract = {Al-doped 4H-SiC epitaxial layers were grown in a hot-wall chemical vapor deposition (CVD) system on commercial 4H-SiC substrates (CREE). The incorporation of Aluminum has been studied in the concentration range from 2*1014cm-3 up to 3*1020cm-3. Epitaxial layers with doping concentration NA-ND> 1019cm-3 were studied by HV-TEM and synchrotron radiation investigations. In the concentration range from 1*1019cm-3 to 3*1020 cm-3, measured by SIMS and Hall investigations, no Aluminum precipitation were detected in the grown layers. For SiC samples with an Al concentration of 1020cm-3 we have been able to detect the Al2p photoemission signal. The Al2p signal is recorded through the oxide layer (thickness of about 0.4nm), it has a main contribution at a binding energy of 73eV which corresponds to the energy typical for elemental Al0. In spectra excited with higher photon energies the sampled photoelectrons originate from deeper layers. In these data we notice an additional shoulder in the Al2p signal at around 71eV. The evidence of two contributions is attributed to the fact that Al is incorporated at different lattice sites. As the latter data represent more bulk like properties we argue that Al in the bulk SiC occupies both, substitutional lattice sites and interstitial sites while in the surface near regions Al is found only at substitutional lattice sites.}, language = {en} } @misc{SchwarzkopfDirsyteDevietal., author = {Schwarzkopf, Jutta and Dirsyte, R. and Devi, A. and Kwasniewski, A. and Schmidbauer, M. and Wagner, Gerd and Michling, Marcel and Schmeißer, Dieter and Fornari, Robert}, title = {Influence of Na on the structure of Bi4Ti3O12 films deposited by liquid-delivery spin MOCVD}, series = {Thin solid films}, volume = {519}, journal = {Thin solid films}, number = {17}, issn = {0040-6090}, pages = {5754 -- 5759}, language = {en} }