Fakultäten & Zentralinstitute

7148 Items

Recent Submissions
Virtuelle Welten – reale Entscheide? Die Alpen im Modellbaukasten

Walz, Ariane ; Gloor, Christian ; Bebi, Peter ; Fischlin, Andreas ; Lange, Eckart ; Nagel, Kai ; Allgöwer, Britta (2008)

Landschaften bieten keinen Raum für Experimente. Was in ihnen realisiert wird, bildet – meist für Jahrzehnte oder gar für Jahrhunderte – einen unauslöschlichen Teil von ihnen. Bevor endgültige Entscheide gefällt werden, ist deshalb umsichtige und vorausschauende Planung gefordert. Computergestützte Modelle erlauben es, Entwicklungsoptionen und Entscheidungsalternativen zu prüfen und zu visualis...

Conditioning fixed-bed filters with fine fractions of granulated iron hydroxide (µGFH)

Hilbrandt, Inga ; Ruhl, Aki S. ; Jekel, Martin (2018-09-25)

The fine fraction of granular ferric hydroxide (µGFH, <0.3 mm) is a promising adsorbent for the removal of heavy metals and phosphate, but properties of µGFH were hitherto not known. The present study aimed at characterizing µGFH regarding its physical and chemical properties and at evaluating methods for the conditioning of fixed-bed filters in order to develop a process that combines filtrati...

Modeling and simulation of electrically driven quantum dot based single-photon sources

Kantner, Markus (2018)

Semiconductor quantum optics is on the leap from the lab to real world applications. The currently unfolding "second quantum revolution" aims at the development of novel quantum technologies that exploit inherent quantum mechanical phenomena like entanglement and quantum superposition for communication and information processing tasks. Many applications, such as eavesdropping-secure encryption ...

Investment banks and underpricing

Baltes, Pascal (2018)

After the Internet Bubble in 1999-2000, US investigators found that investment banks have manipulated initial public offerings (IPO) in differing schemes to create higher profits at the cost of investors and issuing firms. One of these schemes included profit sharing agreements in which an investment bank offered underpriced share allocations of rationed IPOs to buy-side investor clients in ret...

Optical gain and modal loss in AlGaN based deep UV lasers

Martens, Martin Georg Rudolf (2018)

Because of its direct bandgap covering the ultraviolet (UV) spectral region from 360 nm to 200 nm, the AlGaN material system is a promising candidate for the realization of deep UV laser diodes emitting below 300 nm, being an alternative for bulky and energy consuming excimer or frequency multiplied lasers. Possible applications cover e.g. medical detection, gas sensing, material processing, ...

The future of global land use

Kreidenweis, Ulrich (2018)

Global land-use change is a main driver of two of the biggest environmental alterations threatening human well-being: climate change and the decline in biodiversity. Over recent decades, a growing and wealthier population has requested more agricultural products, and this demand has been satisfied by expanding agricultural areas and intensifying production. However, this has posed consequences....

Remarks on thermodynamical terminology

Muschik, Wolfgang (2004)

Often difficulties in understanding thermodynamics arise from using different terminology or semantics. Therefore here some few remarks are made for tending towards a unified thermodynamical terminology.

Thermodynamic interaction between two discrete systems in non-equilibrium

Muschik, Wolfgang ; Berezovski, Arkadi (2004)

A systematic description of the interaction between two systems is presented within the framework of thermodynamics of discrete systems. We distinguish between two situations: a contact between an equilibrium system and a non-equilibrium one, and a contact between two non-equilibrium systems. In the second case the state space includes replacement quantities, which reduce the situation to a con...

Mesoscopic theory of liquid crystals

Muschik, Wolfgang ; Papenfuss, Christina ; Ehrentraut, Harald (2004)

Liquid crystals of uniaxial and biaxial molecules are considered in the framework of the mesoscopic description which is a general tool of continuum theory. A mesoscopic theory introduces the fields beyond hydrodynamics as additional variables of a configuration space, called mesoscopic space, on which the fields appearing in balances are defined. Besides the mesoscopic space, a mesoscopic dist...

Intrusion Detection in Unlabeled Data with Quarter-sphere Support Vector Machines

Laskov, Pavel ; Schäfer, Christin ; Kotenko, Igor ; Müller, Klaus-Robert (2004)

The anomaly detection methods are receiving growing attention in the intrusion detection community. The two main reasons for this are their ability to handle large volumes of unlabeled data and to detect previously unknown attacks. In this contribution we investigate the application of a modern machine learning technique – one-class Support Vector Machines (SVM) – for anomaly detection in unlab...

New Products of Defense Secretion in South East Asian Whip Scorpions (Arachnida: Uropygi: Thelyphonida)

Haupt, Joachim ; Müller, Frank (2004)

Secretion products from the opisthosomal defense gland of south east Asian whip scorpions were identified for the first time by gas-chromatography and mass-spectrometry. Specimens of the genera Hypoctonus, Typopeltis and Ginosigma were tested. While some ingredients are present in large concentrations, others are possibly only side products and may be synthesized more incidentally. For this rea...

Self-Management – Potentiale, Probleme, Perspektiven

Herrmann, Klaus ; Mühl, Gero ; Geihs, Kurt (2004)

Gordon Moores Gesetz vom exponentiellen Wachstum der Transistordichte pro Quadrat-Zoll hat seit 1965 die IT-Industrie geprägt. Mit der damit einhergehenden Explosion der Rechnerleistung wurde die Software immer leistungsfähiger, und man ist dazu übergegangen, Rechnersysteme zu vernetzen und Anwendungen zu verteilen. Eine Folge dieser Entwicklungen ist die rapide zunehmende Komplexität der moder...

Fragmentable Heterogeneous Cocatalysts for the Metallocene-Catalyzed Polymerization of Olefins, I. Surface Modification of Silica and Characterization of the Resulting Carriers

Schumann, Herbert ; Widmaier, Ralf ; Lange, Katharina C. H. ; Wassermann, Birgit C. (2005)

Surface modification of pre-dried spherical silica nano-particles with diameters of 235 nm and 10 to 20 nm and of commercially available non-spherical silica materials using various aminoalkyltrialkoxysilanes and α-ω-bis(alkoxysilyl)organyls (organyl = alkanediyl, aminoalkanediyl, polyether, polysiloxane) has been performed in suspension in solvents with water. The quantity of water has a domin...

Fragmentable Heterogeneous Cocatalysts for the Metallocene-Catalyzed Polymerization of Olefins, II [1]. Preparation, Characterization and Testing of the Cocatalysts and Microscopic Evaluation of the Polyethylene

Schumann, Herbert ; Widmaier, Ralf ; Lange, Katharina C. H. ; Wassermann, Birgit C. (2005)

Surface modified silica were reacted with different aluminiumalkyls AlR2R’ (R = Me, Et, i-Bu, R’ = H, Me, Et, i-Bu), oligomeric methylaluminoxane (MAO) and combinations of both, to yield heterogeneous cocatalysts. These cocatalyts were employed to polymerize ethylene using zirconocene dichloride as the catalyst. The polymerization activity profiles have been recorded and compared with the infor...

2,5-Dimethyl-3,6-bis[(2,6-diisopropylphenylimino)methyl]- and 2,6-Bis[(2,6-diisopropylphenylimino)methyl]pyrazine: Two New Chelating Ligands for Transition Metal Complexes

Schumann, Herbert ; Luo, He-Kuan (2005)

The reaction of tetramethylpyrazine with SeO2 yields 2,5-dimethylpyrazine-3,6-dicarboxaldehyde (1) from which the 2,5-dimethyl-3,6-bis[(2,6-diisopropylphenylimino)methyl]pyrazine (2) was synthesized by treatment with 2 equivalents of 2,6-diisopropylaniline. 2,6-Dimethylpyrazine reacts with benzaldehyde to give 2,6-distyrylpyrazine (3). Ozonolysis of 3, followed by treatment with Na2SO3 and 2,6-...

Di-, Hexa- und Deca-substituierte Decaphenylferrocene

Schumann, Herbert ; Sühring, Klaudia (2005)

5-Bromo-1,2,3,4-tetraphenyl-5-p-tolyl-1,3-cyclopentadiene (1a), 5-Bromo-1,4-di-phenyl-2,3,5- tri-p-tolyl-1,3-cyclopentadiene (1b), 5-Bromo-1,2,3,4,5-penta-p-tolyl-1,3-cyclopentadiene (1c), 5- Bromo-1,2,3,4-tetraphenyl-5-p-bromophenyl-1,3-cyclopentadiene (1d), and 5-Bromo-1,2,3,4-tetraphenyl- 5-p-anisyl-1,3-cyclopentadiene (1e) react with ironpentacarbonyl in m-xylene to yield the corresponding ...

Metallkomplexe von 2,2’-Dipyridyldisulfid mit Quecksilber(II)-, Cadmium(II)- und Zink(II)-Halogeniden und mit Cadmium(II)- Trifluormethansulfonat

Pickardt, Joachim ; Chrzanowski, Lars von ; Steudel, Ralf ; Borowski, Marina ; Beck, Sebastian (2005)

Crystals of diiodo-2,2’-dipyridyldisulfide mercury(II) [HgI2(C5H4N)2S2], dichloro-2,2’-dipyridyldisulfide zinc(II) [ZnCl2(C5H4N)2S2], dibromo-2,2’-dipyridyldisulfide cadmium(II) [CdBr2 (C5H4N)2S2], diiodo-2,2’-dipyridyldisulfide cadmium(II) [CdI2(C5H4N)2S2], and diaquo 2,2’-dipyridyldisulfide cadmium(II) trifluoromethanesulfonate [Cd(H2O)2(C5H4N)2S2](CF3SO3)2, were obtained by evaporation of so...

Studies on the Thermolysis of Ether-Stabilized Lu(CH2SiMe3)3. Molecular Structure of Lu(CH2SiMe3)3(THF)(diglyme)

Rufanov, Konstantin A. ; Freckmann, Dominique M. M. ; Kroth, Heinz-Jürgen ; Schutte, Stefan ; Schumann, Herbert (2005)

Lu(CH2SiMe3)3(THF)2 (2) decomposes slowly at room temperature with formation of Me4Si. In order to understand the mechanism of this elimination process, Lu(CH2SiMe3)3([D8]-THF)2 (1), Lu(CH2SiMe3)3(THF)(DME) (3), and Lu(CH2SiMe3)3(THF)(diglyme) (4) were prepared. The results of 1H NMR spectroscopic studies of the decomposition in solution exclude an α- as well as a β -H elimination mechanism and...

Deca(4-methylbenzyl)ferrocen und -stannocen

Schumann, Herbert ; Sühring, Klaudia ; Weimann, Roman ; Hummert, Markus (2005)

Cyclopentadiene reacts with five equivalents of 4-methylbenzylalcohol (1:5,6 mole ratio) and sodium yielding penta(4-methylbenzyl)cyclopenta-2,4-diene (1), which upon treatment with butyl lithium affords the lithium salt [(4-MeC6H4CH2)5C5]Li (2). The reactions of 2 with FeCl2 and SnCl2 result in the formation of deca(4-methylbenzyl)ferrocene (3) and deca(4-methylbenzyl)stannocene (4), respectiv...

Flow Velocity and Effective Viscosity of a Fluid Containing Rigid Cylindrical Inclusions

Hess, Siegfried (2005)

The determination of the flow properties of a fluid containing a cylindrical inclusion with its long axis oriented parallel to the vorticity direction is a 2-dimensional problem which is treated as a special case in a calculation of the corresponding D-dimensional problem. The velocity and pressure are obtained from the solution of the equations of hydrodynamics where D-dimensional multipole po...