bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ordnungsreduktion linearer zeitinvarianter Finite-Elemente-Modelle mit multivariater polynomieller Parametrierung (Model Order Reduction of Linear Finite Element Models Parameterized by Polynomials in Several Variables)
Authors: Farle Ortwin , Hill Volker , Ingelström Pär , Dyczij-Edlinger Romanus 
Published: April 2006

Abstract
Der vorliegende Beitrag stellt ein Verfahren zur Ordnungsreduktion linearer Gleichungssysteme vor, die durch Polynome in mehreren Variablen parametriert sind und aus der Finite-Elemente-Methode hervorgehen. Der vorgeschlagene Ansatz beruht auf multivariaten Krylov-Unterräumen und erweitert bestehende Verfahren in zweierlei Hinsicht: Erstens beinhaltet er einen neuen Algorithmus zur Berechnung einer stabilen Basis für das reduzierte System, und zweitens verallgemeinert er das Konzept der Krylov-Unterräume höherer Ordnung auf Mehrparametersysteme.
Modellreduktion in elastischen Mehrkörpersystemen (Model Reduction in Flexible Multibody Systems)
Authors: Lehner Michael , Eberhard Peter 
Published: April 2006

Abstract
In dieser Arbeit wird die Verwendung von Krylov-Unterraummethoden zur Reduktion flexibler Körper in elastischen Mehrkörpersystemen vorgeschlagen. Mit diesen Verfahren können reduzierte Modelle sehr gut auf den zu untersuchenden Frequenzbereich und die wirkenden Kräfte abgestimmt werden. Dadurch ist es möglich, für bestimmte Problemklassen bessere Approximationen zu erzeugen als bei Verwendung der in diesem Anwendungsbereich üblichen Verfahren auf Basis der modalen Reduktion.
Zur zeitdiskreten Implementierung nichtlinearer Regelgesetze (On the Discrete-time Implementation of Nonlinear Control Laws)
Authors: Holl Johann , Schlacher Kurt 
Published: April 2006

Abstract
Basierend auf wohlbekannten Entwurfsmethoden der nichtlinearen Regelungstheorie wird für die Klasse der zeitkontinuierlichen dynamischen Systeme ein Zugang zur modellbasierten zeitdiskreten Regelung vorgestellt. Die Berechnung der Stellfolge erfolgt durch die Forderung nach Äquivalenz der Trajektorien des betrachteten dynamischen Systems und denen des durch zeitkontinuierliche Regelung resultierenden geschlossenen Kreises zu diskreten Zeitschritten. Der dazu benötigte Fluss des nichtlinearen zeitkontinuierlichen Systems wird hierfür auf dem Intervall zweier aufeinander folgender Abtastzeitpunkte durch eine Lie-Reihe oder numerische Integration approximiert. In diesem Beitrag werden insbesondere die Methoden der exakten Linearisierung, Regelgesetze basierend auf differentieller Flachheit sowie ein passivitätsbasierter Reglerentwurf hinsichtlich ihrer zeitdiskreten Implementierung untersucht. Erörtert wird auch, dass die Trajektorienfolgeregelung keine Neuplanung der gewünschten Trajektorie erfordert. Schließlich wird die vorgeschlagene Methode anhand der Regelung eines stufenlosen Getriebes illustriert.
EDA — Eine Voraussetzung für die Nanoelektronik (EDA — a Precondition for Nanoelectronics)
Authors: Treytnar Dieter , Popp Ralf 
Published: April 2006

Zusammenfassung
Der fehlerfreie und effiziente Entwurf von hochkomplexen Chips mit oft mehr als 100 Millionen Transistoren ist heute eine der größten Herausforderungen beim Chip-Design. Ohne Entwurfsautomatisierung (Electronic Design Automation, EDA) ist sie nicht zu bewältigen. Um die hierzu notwendigen intensiven Forschungsarbeiten voranzutreiben, fördert das BMBF diesen Bereich in hohem Maße und hilft damit deutsche Kernkompetenzen wie Automotive und Telekommunikation voranzutreiben.
Effiziente Selbstkonfiguration mobiler Ad-hoc-Netze (Efficient Self-Configuration of Mobile ad hoc Networks)
Authors: Weniger Kilian Alexander 
Published: April 2006

Zusammenfassung
Mobile Ad-hoc-Netze (MANET) ermöglichen die Datenkommunikation vollkommen unabhängig von einer Kommunikationsinfrastruktur und eröffnen dadurch zahlreiche neue Möglichkeiten der mobilen Kommunikation. Auf Grund der speziellen Randbedingungen in diesen Netzen, wie die Notwendigkeit zur Selbstorganisation, die hochdynamische Netztopologie und die beschränkte Bandbreite und Energie, entstehen jedoch neue Anforderungen an Systemkonzepte und Protokolle. Eine essentielle, bisher aber nicht zufriedenstellend gelöste Problemstellung in diesem Zusammenhang ist die effiziente und zuverlässige Selbstkonfiguration solcher Netze, auch Autokonfiguration genannt. Wichtigster Konfigurationsparameter im Zusammenhang mit IP ist eine netzweite eindeutige IP-Adresse der Netzwerkschnittstelle. Dieser Artikel gibt einen Überblick über einige Ergebnisse der Dissertation mit dem Titel “IP-Autokonfiguration in mobilen Ad-hoc-Netzwerken”, in der mögliche Ansätze analysiert und eine sehr effiziente und zuverlässige Lösung zur dezentralen und automatischen IP-Adresszuweisung in MANETs vorgeschlagen wird.
Von Wissensportalen zu Wissensinfrastrukturen – Gestaltung von IT für die Wissensarbeit mit dem Konzept der Wissenslage (From Knowledge Portals to Knowledge Infrastructures – Designing IT for Knowledge Work with the Concept of Knowledge Stance)
Authors: Maier Ronald 
Published: April 2006

Zusammenfassung
Wissensintensive Arbeit stellt einen zunehmenden Anteil der Tätigkeiten in Unternehmen und Organisationen dar. Die Steigerung ihrer Produktivität verlangt nach einer gleichermaßen organisatorischen wie informations- und kommunikationstechnischen Unterstützung durch Instrumente des Wissensmanagements. Entsprechend gestaltete Wissensportale bieten geeignete Plattformen für deren Implementierung. Bei der Entwicklung von Wissensportalen werden weit reichende Anforderungen an Angebot, Zugang und Integration von Daten, Dokumenten und Diensten gestellt. Deren konsequente Umsetzung bedeutet den Aufbau einer unternehmensweiten Wissensinfrastruktur.
Virtuelle Portale – Mandantenfähigkeit für Websphere Portal Server (Virtual Portal – Multiple Tenant Capabilities for Websphere Portal)
Authors: Stober Thomas 
Published: April 2006

Zusammenfassung
Websphere.® Portal 5.1 unterstützt ein Konzept von virtuellen Portalen, die ohne wiederholtes Durchführen des Installationsprozesses auf sehr komfortable Weise angelegt werden können. Derartige virtuelle Portale entstehen durch Partitionieren einer existierenden Installation in mehrere logische Server. Endanwender bemerken dabei keinerlei Unterschied, ob ihre Anfrage von einer Vollinstallation oder einem virtuellen Portal bedient wird. Dieser Beitrag beschreibt die Konzepte, die dieser Lösung zugrunde liegen. Außerdem wird auf Anwendungsszenarien eingegangen, in denen virtuelle Portale genutzt werden, um die Mandantenfähigkeit von Websphere Portal zu erreichen.
Wirtschaftlichkeit von Unternehmensportalen (Economic Valuation of Enterprise Portals)
Authors: Okujava Shota , Remus Ulrich 
Published: April 2006

Zusammenfassung
Mittlerweile erkennen immer mehr Unternehmen, dass Portalprojekte enorm komplex, zeit- und kostenintensiv sind. Kosten und Nutzen, um ein Unternehmensportal aufzubauen und zu betreiben, sollten daher sorgfältig abgewägt werden. Häufig fehlen jedoch genaue Kennzahlen, die detailliert die Wirtschaftlichkeit einer Portalinvestition darstellen. Ziel des Artikels ist daher die Analyse der relevanten Faktoren, die Gegenstand einer Wirtschaftlichkeitsbetrachtung von Unternehmensportalen sind. Dazu werden Vorgehen zur Wirtschaftlichkeitsanalyse, sowie wesentliche Faktoren bzgl. des Nutzens, der Kosten und des Risikos bei der Implementierung eines Unternehmensportals, strukturiert nach den wesentlichen Portaltypen B2E und B2C diskutiert.
Enumeration of closest-packings by the space group: a simple approach
Authors: Iglesias Juan E. 
Published: April 2006

Abstract
The problem of enumerating the possible closest-packings of equal spheres having a period P for each of the possible space groups is solved by systematic exploitation of the properties of the two-color symmetry group of the cyclotomic representation of the Zhdanov symbol. No sophisticated combinatorial or group-theoretical techniques are required, and for some space groups, non-recursive, simple analytical expressions are obtained through the use of Möbius Inversion Formula. A corollary to Möbius theorem, used in the derivation, has been proved.
Uranyl oxalate hydrates: structures and IR spectra
Authors: Giesting Paul A. , Porter Nathan J. , Burns Peter Carman 
Published: April 2006

Abstract
The novel compound (UO2)2C2O4(OH)2(H2O)2 (UrOx2A) and the previously studied compound UO2C2O4(H2O)3 (UrOx3) have been synthesized by mild hydrothermal methods. Single crystal diffraction data collected at 125 K using MoK
α radiation and a CCD-based area detector were used to solve and refine the crystal structures by full-matrix least-squares techniques to agreement indices (UrOx2A, UrOx3) wR
2 = 0.037, 0.049 for all data, and R1 = 0.015, 0.024 calculated for 1285, 2194 unique reflections respectively. The compound UrOx2A is triclinic, space group P-1, Z = 1, a = 5.5353(4), b = 6.0866(4), c = 7.7686(6) Å, α = 85.6410(10)°, β = 89.7740(10)°, γ = 82.5090(10)°, V = 258.74(3) Å3. The compound UrOx3 is monoclinic, space group P21/c, Z = 4, a = 5.5921(4), b = 16.9931(13), c = 9.3594(7) Å, β = 99.5330(10)°, V = 877.11(11) Å3. The structures consist of chains of uranyl pentagonal bipyramids connected by oxalate groups and, in UrOx2A, hydroxyl groups; UrOx2A is also notable for its high (2 : 1) ratio of uranyl to oxalate groups, higher than any observed in other published structures of uranyl oxalates. The structure determined for UrOx3, previously studied by Jayadevan and Chackraburtty (1972); Mikhailov et al. (1999) is in agreement with the previous results; however, the increased precision of the present low-temperature structure refinement allows for the assignment of H atom positions based on the difference Fourier map of electron density. The infrared spectra of these two materials collected at room temperature are also presented and compared with previous work on uranyl oxalate systems.
The crystal structure of ZSM-10, a powder X-ray and electron diffraction study
Authors: Dorset Douglas L. 
Published: April 2006

Abstract
The crystal structure of the aluminosilicate, ZSM-10 (T108O216, where T = Si, Al), has been determined from electron diffraction and powder X-ray diffraction data. The material crystallizes in space group P6/mmm, where a = 31.390(2), c = 7.5147(8) Å. The framework [001] projection was determined independently with 300 kV precession electron diffraction amplitudes by direct methods. T-site positions in this projection were consistent with two models proposed in 1996 by Higgins and Schmitt. Subsequent Rietveld refinement favors their model A, comprising stacked cancrinite cages and hexagonal prisms. The framework density is 16.6 T sites/1000 Å3, similar to zeolite framework LTL. However, the refinement against synchrotron data from a dehydrated sample (R
wp = 0.1600, R(F
2) = 0.1418) finds no extra-framework species, despite the detection of some K+ in the material.
The structure of the red-brown form of [Fe2(η5-C5H4Me)2(CO)(CN)(μ-CO)(μ-CNMe2)] and its confirmation as a cis isomer
Authors: Boss Kevin , Manning Anthony R. , Müller-Bunz Helge 
Published: April 2006

Abstract
The crystal and molecular structure of the red brown form of [Fe2(η5-C5H4Me)2(CO)(CN)(μ-CO) · (μ-CNMe2)] has been determined by X-ray crystallography. It crystallises with one molecule per asymmetric unit (P21/c) and CO/CN disorder among the terminal ligands. It is a cis isomer with a non-planar Fe2(μ-C)2 bridge having a dihedral angle of 154° between the two Fe2C planes. The Fe—C distances to the 2-electron donor ligands (CO, CN, μ-CO and μ-CNMe2
+) can be rationalised on the basis of their σ donor and π acceptor abilities.
Crystal structure of silver salicylate C7H5AgO3 solved by reverse Monte-Carlo method from X-ray powder diffraction data and confirmed on single crystal
Authors: Wolcyrz Marek , Paściak Marek , Kowalczyk Jerzy , Maciejewski Marcin 
Published: April 2006

Abstract
The crystal structure of silver salicylate C7H5AgO3 has been solved originally on powder sample by molecular modeling and reverse Monte-Carlo (RMC) algorithm and then confirmed by X-ray diffraction single crystal structure solution and refinement. C7H5AgO3 crystallizes in the monoclinic symmetry (space group P21/n) with the lattice parameters: a = 10.9868(15) Å, b = 8.8190(18) Å, c = 7.398(2) Å, β = 112.27(3)° (data from single crystal). The structure consists of [C6H4(OH)COOAg— AgOOCC6H4(OH)] dimers and is stabilized by weak intermolecular interactions of the C—H···O type. The comparison of the two independent structure solutions confirmed the effectiveness of the RMC procedure based on powder data to solve the unknown organic structures of the mediocre complexity even using the laboratory X-ray sources.
Synthesis, crystal structure and magnetic behaviourof a mononuclear Fe(III) — Schiff base metal complex
Authors: Nazir Hasan , Akben Nimet Sapmaz , Ateş Meltem Bürke , Sözeri Hüseyin , Ercan Ismail , Atakol Orhan , Ercan Filiz 
Published: April 2006

Abstract
A complex from Fe(II) and a hexa-dentate linear ligand containing O2N4 donor atoms were prepared and the structure enlightened with X-ray diffraction. The Fe(II) ion in the complex was seen to be oxidized to form a Fe(III) complex, [C20H24Cl3N4O2]Fe and the three chloride ions were situated at a distance of Fe…Cl(1) 3.976(5), Fe…Cl(2) 4.479(3) and Fe…Cl(3) 7.509(4) Å outside the coordination sphere. The Fe(III) ion has an octahedral coordination sphere and as expected the two oxygen donor atoms are coordinated in a -cis position. The Fe—O, Fe—Nimin and Fe—Namine distances are 1.880(3) Å, 1.931(4) Å and 2.004(4) Å, respectively.
The molecular structure of 2-phenylbenzimidazole: a new example of incommensurate modulated intramolecular torsion
Authors: Zúñiga F. Javier , Palatinus Lukáš , Cabildo Pilar , Claramunt Rosa M. , Elguero José 
Published: April 2006

Abstract
Molecular crystals of 2-phenylbenzimidazole, C13H10N2, exhibit a one-dimensional incommensurate structure. The structure has been solved by charge flipping and refined using the superspace formalism in the (3 + 1) D superspace group C2/c(0b0) s0 with modulation wave-vector q = 0.368b*. The unit cell contains 8 molecules, each one disorderly occupying two configurations related by inversion center. The refinement based on a molecular model with two rigid-body parts per molecule includes up to second order Fourier amplitudes for the modulation. The displacive modulation involves a significant intra-molecular twist between the phenyl and the benzimidazole parts.
Non-linear optical properties and absolute structure of metastable 4-methyl benzophenone
Authors: Kaminsky Werner , Weckert Edgar , Kutzke Hartmut , Glazer A. Michael , Klapper Helmut 
Published: April 2006

Abstract
Metastable 4-methyl benzophenone (4-MBP, C14H12O) crystallizes in the polar (pyroelectric) and enantiomorphic space groups (SG) P31 and P32. The optical rotation tensor has been measured for 670 nm and the material was tested for evidence of phase-matchability. The absolute structure was determined via three-beam diffraction, showing that the structural right-hand screw 31 is combined with positive (right-handed, i.e. clockwise when looking towards the light source) optical rotation, for both tensor components ρ
11 = ρ
22 = 26(5)°/mm, ρ
33 = 8.3(5)°/mm (contrary to low-quartz which shows negative optical rotation for ρ
33 and positive rotation for ρ
11 in right-hand SG P312).
The non-linear optical tensors for optical rotation, d-coefficients, electro-optic effect and electrogyration have been calculated using a set of electronic polarizabilities as input parameters for a dipole-dipole interaction model that reproduces the experimental refractive indices and optical rotation. Unusually high polarizability volumes are needed for hydrogen atom bonding to aromatic carbons in order to model the optical tensors. The non-linear optical coefficients are of medium size.
Electroless, Electrolytic and Galvanic Copper Deposition with the Scanning Electrochemical Microscope (SECM)
Authors: Radtke Valentin , Heß Christian , Souto Ricardo M. , Heinze Jürgen 
Published: April 2006

Summary
The Scanning Electrochemical Microscope (SECM) can be used with different techniques of microstructured copper deposition. A first approach involves the electrolytic copper deposition on noble metals, whereby copper ions are released from a complex by a suitable tip reaction and then reduced on the polarised conducting surface to form a copper microstructure. The second approach is very similar to the first, but does not involve polarising the substrate. It generates a tip-induced microgalvanic cell, the positive electromotoric force of which is constituted by two electrochemical reactions at different areas of the substrate. Finally the electroless copper deposition is performed on nonconducting surfaces like glass or semiconducting surfaces like silicon. This involves locally reducing a suitable precursor film whose surface has been previously immobilised.
Amphiphilic Block Copolymers that Form Micelles but Are not Surface Active and Bind Normal Surfactants
Authors: Eghbali Elham , Hoffmann Heinz 
Published: April 2006

Summary
The phase diagram and the properties of the aqueous phases of the AB block copolymer poly-n-butylacrylate-block-polyacrylic acid (nBuA100-b-AA150) has been studied as a function of the neutralisation degree α with NaOH. Aqueous solutions of the block copolymer with α < 0.1 are turbid and separate into two phases while solutions with α > 0.1 are transparent and single phase. The viscosities of such solutions increase with α and pass over a maximum at α = 0.5. Solutions with a concentration of Cp ≥ 1% and at α = 0.5 are highly viscoelastic and have a yield stress value. Cryo-TEM micrographs show that globular micelles are present in the viscoelastic solutions. The micelles have a polydisperse size distribution. The radius of the hydrophobic core varies from about 100 Å to 200 Å what is the length of the fully stretched hydrophobic block.
The rheological properties of the solutions are explained on the basis of the globular core–shell micelles where the polyelectrolyte chains form a corona around the hydrophobic block. Most of the counter ions are in the condensed and free state inside the corona. Some of the counter ions are outside of the corona and form an electrical double layer whose thickness depends on α. The viscoelastic properties of the solutions are thus given by the dense packing of the charged globular micelles. The decrease of the viscosity for α > 0.5 comes about by the shrinkage of the thickness of the electrical double layer. With increase of excess salt the double layer and the corona also shrink and the viscoelastic properties break down. With adsorption of zwitterionic surfactants the viscoelastic properties also disappear. Cryo-TEM micrographs of the block copolymers at α = 0.5 with adsorbed zwitterionic surfactants show that the polyelectrolyte chains of the block copolymers are wrapped around small globular micelles of the zwitterionic surfactants. The supra-molecular structures look like raspberry-like micelles.
The block copolymers show a very unusual amphiphilic behavior. For a neutralisation degree of α > 0.1 the compounds do not seem to adsorb at the water surface even though the compounds form micelles in the bulk solution. The micellar solutions have the same surface tension of water. The acidic form of the compound however is surface active.
Activation Parameters of the Eu3+/Eu2+ Electrode Reaction in Mixed Solvents
Authors: Kisova L. , Komenda J. 
Published: April 2006

Summary
The rate constants for the electrochemical reduction of Eu3+ in water–acetone and water–dimethylformamide solvent mixtures with different parts of the organic component were measured in the temperature range 15°C–40°C. The activation parameters for this reaction were evaluated. While the activation enthalpy does not depend on the composition of the solvent, the activation entropy changes follows the changes of reaction rates.
The entropy contribution (responsible for the form of dependence of rate constants on the composition of the solvent) is obviously related to structure changes of the resolvatated particle.
An Empirical Approach to Modeling Ion Size Effects in Diffuse Double Layer Theory
Authors: Smagala Thomas G. , Fawcett W. Ronald 
Published: April 2006

Summary
A novel empirical model for the diffuse double layer is found by generalizing the simple analytical equations of Gouy–Chapman theory. Two adjustable parameters are introduced into the Boltzmann equation for the exponential dependence of the ion–wall correlation functions on the diffuse layer potential. Optimal parameter values and model validation for 1:1 and 2:1 electrolytes are provided by Monte Carlo simulations. Simple relationships are obtained between these empirical parameters and those commonly associated with the mean-spherical approximation. The new empiricism accurately models diffuse layer potential profiles and ion–wall correlation functions for a restricted 1:1 electrolyte in a primitive solvent.
Novel Insight into the Protonation–Deprotonation Equilibria of Tetracycline, Sancycline and 10-Propoxy-Sancycline in Aqueous Solution. I. Analysis of the pH-Dependent UV/vis Absorption Spectra by the SVD Technique
Authors: Schmitt Matthias O. , Schneider Siegfried 
Published: April 2006

Summary
The UV/vis absorption spectra recorded during titration experiments (pH2 ↔ pH11, ΔpH ∼ 0.33) were subjected to a principal component analysis. The aim was to determine by means of the program SPECFIT the number of significant components and to reduce the noise in the spectra. The attempt to achieve a global fit of the “noise-reduced” data was in general successful if 5 or more independent species were considered. The necessity to include a larger number of species than the 4 occuring within the simple protonation-deprotonation scheme of a triprotic acid provides strong evidence for conformational heterogeneity at various levels of protonation. Only if this heterogeneity is taken into account, the analysis yields the correct pK
a-values. For tetracycline, slow conformational changes are suggested to occur in the neutral state. Consequently, tetracycline adopts conformation 2 in alkaline solution if the pH is raised slowly up to pH11, whereas if it is dissolved directly in buffer solution at pH2 or pH11 it adopts conformation 1 (like in the crystal). In this conformation, tetracycline degrades rapidly in a methanol–water mixture around pH11 probably by methylation of the 11,12-β-carbonyl group. Sancycline and 10-propoxy-sancycline are stable at any pH, the conformational changes are proposed to occur preferentially in the anionic state. Because of these conformational changes, the pK
a-values derived from forward and backward titration can differ up to 0.4 pH units. In addition, there is evidence that C10-OH does not dissociate at pH less than 11.
In contrast to a widely accepted hypothesis, 4-epi-tetracycline also changes its conformation in the anionic form. This shows that CD spectra are not suited to draw conclusions on molecular geometry if the total net charge changes.
UV and Visible Light Acrylate Photopolymerisation Initiated by Nitrogen- or Carbon-Doped Titanium Dioxide
Authors: Damm C. , Sakthivel S. , Kisch H. 
Published: April 2006

Summary
Nitrogen and carbon doped titania powders initiate acrylate polymerisation upon UV excitation. Time resolved photovoltage measurements afford surface charge carrier lifetimes of 7–8 ms for undoped and N-doped titania, whereas 12 ms are observed for the C-doped semiconductor. These values correlate with the observation that the polymerisation rate constants are similar for titania or N-doped titania but about two times larger for the C-doped material. Wavelength dependent polymerisation experiments indicate that visible light polymerisation is possible only with carbon-doped titania. This suggests that hole relaxation to dopant-centered surface states is much more efficient in nitrogen-doped titania. These experimental findings are in accord with the assumption that polymerisation is initiated by hole oxidation of the acrylate.