Open Access. Powered by Scholars. Published by Universities.®
Materials Science and Engineering Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Physical Sciences and Mathematics (105)
- Physics (93)
- Condensed Matter Physics (83)
- Chemical Engineering (60)
- Other Materials Science and Engineering (46)
-
- Ceramic Materials (42)
- Chemistry (40)
- Metallurgy (38)
- Engineering Physics (37)
- Materials Chemistry (30)
- Physical Chemistry (30)
- Applied Mathematics (28)
- Other Applied Mathematics (28)
- Complex Fluids (27)
- Other Chemical Engineering (20)
- Mechanical Engineering (18)
- Nanoscience and Nanotechnology (11)
- Polymer Science (11)
- Manufacturing (8)
- Biomedical Engineering and Bioengineering (5)
- Electrical and Computer Engineering (5)
- Polymer and Organic Materials (4)
- Semiconductor and Optical Materials (4)
- Structural Materials (4)
- Thermodynamics (4)
- Aerospace Engineering (3)
- Biological Engineering (3)
- Biology and Biomimetic Materials (3)
- Keyword
-
- Crystal structure (10)
- Alloy/materials theory (9)
- Lawrence Berkeley National Laboratory (8)
- Block copolymers (5)
- Cracks (4)
-
- Transmission electron microscopy (4)
- Copper (3)
- Eddy currents (3)
- Electron densities of states (3)
- Geological and Atmospheric Sciences (3)
- Grain boundaries (3)
- Melting (3)
- Monte Carlo methods (3)
- Nickel (3)
- Phase transitions (3)
- Piezoelectric fields (3)
- Single crystals (3)
- Skin effect (3)
- Texture (3)
- Thermodynamic properties (3)
- Aluminum (2)
- Analytical solution (2)
- Bismuth (2)
- Block copolymer (2)
- Cobalt compounds (2)
- Computer simulation (2)
- Crystal structures (2)
- Density functional theory (2)
- Electrical resistivity (2)
- Electronic structure (2)
- Publication Year
Articles 1 - 30 of 239
Full-Text Articles in Materials Science and Engineering
Mild Yet Phase-Selective Preparation Of Tio2 Nanoparticles From Ionic Liquids – A Critical Study, Tarek Alammar, Heshmat Noei, Yuemin Wang, Anja V. Mudring
Mild Yet Phase-Selective Preparation Of Tio2 Nanoparticles From Ionic Liquids – A Critical Study, Tarek Alammar, Heshmat Noei, Yuemin Wang, Anja V. Mudring
Anja V. Mudring
The phase selective synthesis of nanocrystalline TiO2, titania, in ionic liquids (ILs) is explored. The influence not only of the IL but also of the Ti-precursor, pH, and temperature is investigated. Sonochemical synthesis, microwave synthesis and conventional heating are compared. In the case of Ti(OiPr)4 (OiPr ¼ isopropyl) as the Ti-source the ILs [C4mim][Tf2N] (1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide), [C3mimOH][Tf2N] (1-(3-hydroxypropyl)-3-methylimidazolium bis(trifluoromethanesulfonyl)amide), [C4Py]- [Tf2N] (butylpyridinium bis(trifluoromethanesulfonyl)amide), [N1888][Tf2N] (methyltrioctylammonium bis- (trifluoromethanesulfonyl)amide), and [P66614][Tf2N] (tetradecyltrihexyl phosphonium bis(trifluoromethanesulfonyl) amide) led at ambient temperature to TiO2 in the form of anatase. The morphology of nano-anatase is controlled by the IL cation. Anatase nanospheres with a crystal size …
Tin Dioxide–Carbon Heterostructures Applied To Gas Sensing: Structure-Dependent Properties And General Sensing Mechanism, Catherine Marichy, Patricia A. Russo, Mariangela Latino, Jean-Philippe Tessonnier, Marc-Georg Willinger, Nicola Donato, Giovanni Neri, Nicola Pinna
Tin Dioxide–Carbon Heterostructures Applied To Gas Sensing: Structure-Dependent Properties And General Sensing Mechanism, Catherine Marichy, Patricia A. Russo, Mariangela Latino, Jean-Philippe Tessonnier, Marc-Georg Willinger, Nicola Donato, Giovanni Neri, Nicola Pinna
Jean-Philippe Tessonnier
Carbon materials such as carbon nanotubes (CNTs), graphene, and reduced graphene oxide (RGO) exhibit unique electrical properties, which are also influenced by the surrounding atmosphere. They are therefore promising sensing materials. Despite the existence of studies reporting the gas-sensing properties of metal oxide (MOx) coated nanostructured carbon, an incomplete understanding of their sensing mechanism remains. Here we report a systematic study on the preparation, characterization, and sensing properties of CNT and RGO composites with SnO2 coating. Atomic layer deposition (ALD) was applied to the conformal coating of the inner and outer walls of CNTs with thin films of SnO2 of …
Yttrium(Iii) Oxomolybdates(Vi) As Potential Host Materials For Luminescence Applications: An Investigation Of Eu3+-Doped Y2[Moo4]3 And Y2[Moo4]2[Mo2o7], Sonja Laufer, Sabine Strobel, Thomas Schleid, Joanna Cybinska, Anja V. Mudring, Ingo Hartenbach
Yttrium(Iii) Oxomolybdates(Vi) As Potential Host Materials For Luminescence Applications: An Investigation Of Eu3+-Doped Y2[Moo4]3 And Y2[Moo4]2[Mo2o7], Sonja Laufer, Sabine Strobel, Thomas Schleid, Joanna Cybinska, Anja V. Mudring, Ingo Hartenbach
Anja V. Mudring
Two ternary yttrium(III) oxomolybdates(VI) are investigated, both structurally and spectroscopically. The crystal structure of Y2[MoO4]3 was solved at room temperature in the orthorhombic space group Pba2 (a = 1030.21(3), b = 1032.41(3), c = 1057.25(3) pm, Z = 4). In the unit cell, three discrete ortho-oxomolybdate(VI) units [MoO4]2− and two Y3+ cations, both with CN = 7 featuring a monocapped trigonal-prismatic oxygen environment, can be distinguished. Y2[MoO4]2[Mo2O7] crystallizes monoclinically in the space group P21/c (a = 681.85(2), b = 959.13(3), c = 1052.99(3) pm, β = 105.586(2)°) with two formula units per unit cell. In this compound the anionic environment …
Interface-Assisted Ionothermal Synthesis, Phase Tuning, Surface Modification And Bioapplication Of Ln3+-Doped Nagdf4 Nanocrystals, Qiang Ju, Paul S. Campbell, Anja V. Mudring
Interface-Assisted Ionothermal Synthesis, Phase Tuning, Surface Modification And Bioapplication Of Ln3+-Doped Nagdf4 Nanocrystals, Qiang Ju, Paul S. Campbell, Anja V. Mudring
Anja V. Mudring
Phase-selective synthesis of trivalent lanthanide-doped NaGdF4 nanocrystals, capped by ionic liquid cations bearing long alkyl chains, succeeded via a one-step interface-assisted ionothermal route. Owing to the existence of an interface formed between hydrophobic ionic liquids and ethylene glycol, selectively either pure cubic or hexagonal phase NaGdF4 could be obtained by changing the amount of the added surfactant, polyethyleneimine. By doping various trivalent lanthanide cations, multicolor emissions under excitation by a single wavelength could be achieved. The nanocrystals can be surface derivatized by an amphiphilic polymer and endowed with functional groups that allow the particles to not only be dispersed in …
Phase And Morphology Selective Interface-Assisted Synthesis Of Highly Luminescent Ln3+-Doped Nagdf4 Nanorods, Anja V. Mudring, Qiang Ju
Phase And Morphology Selective Interface-Assisted Synthesis Of Highly Luminescent Ln3+-Doped Nagdf4 Nanorods, Anja V. Mudring, Qiang Ju
Anja V. Mudring
Making use of the multifunctional properties of ionic liquids by employing them as a fluoride resource and hydrophilic phase, we have grown small, monodisperse, highly luminescent Ln3+-doped NaGdF4 nanorods at the interface between octadecene and the reactive ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate. The obtained nanocrystals could further be endowed with functional groups and rendered water dispersible, which allows them to be used for biodetection.
White-Light-Emitting Single Phosphors Via Triply Doped Laf3 Nanoparticles, Chantal Lorbeer, Anja V. Mudring
White-Light-Emitting Single Phosphors Via Triply Doped Laf3 Nanoparticles, Chantal Lorbeer, Anja V. Mudring
Anja V. Mudring
The production of high-quality phosphors for white-emitting applications is an important goal for the settlement of light-emitting diodes (LEDs) in the market and households. Single phosphors directly yielding white emission are advantageous in comparison to a mixture of individual red, green, and blue phosphors as these are hampered by reabsorption of the blue light. Here, a combined approach to uniform, nanoscale particles as single-white-emitting phosphor is realized via an ionic-liquid-based synthesis. LaF3 particles codoped with various amounts of Tm3+, Tb3+, and Eu3+ were synthesized, and their structural, morphological, and optical properties were studied. Small particles with a mean size of …
On The Mesophase Formation Of 1,3-Dialkylimidazolium Ionic Liquids, Mei Yang, Bert Mallick, Anja V. Mudring
On The Mesophase Formation Of 1,3-Dialkylimidazolium Ionic Liquids, Mei Yang, Bert Mallick, Anja V. Mudring
Anja V. Mudring
A series of seven different 1,3-dialkylimidazolium-based ion-pair salts with the same molecular weight and size but different symmetries was synthesized. For all salts, bromide was chosen as the counterion, giving the series ([CnIMCm][Br]), where IM = imidazolium and Cn and Cm are varying N-alkyl substituents with n + m = 13. Thus, the effect of symmetry on the physicochemical properties, such as thermal transitions, densities and viscosities and particularly mesophase formation, is investigated herein. All salts are fully characterized by NMR spectroscopy and mass spectrometry, and their physicochemical properties such as thermal transitions, densities, and viscosities are reported. Single crystal …
Quantum Chemistry Simulations Using Optimization Methods, Kumara Sastry, Duane D. Johnson, Alexis L. Thompson, Todd J. Martinez, David E. Goldberg
Quantum Chemistry Simulations Using Optimization Methods, Kumara Sastry, Duane D. Johnson, Alexis L. Thompson, Todd J. Martinez, David E. Goldberg
Duane D. Johnson
Embodiments of the present invention provide, among other things, methods, apparatus, and systems for tuning a semiempirical process for predicting energy for different molecular configurations. In an example method, an energy value and an energy gradient are determined for each of a plurality of molecular configurations using an accurate method. A functional form of the semiempirical process is optimized using the determined energy values and energy gradients via multiobjective optimization. The functional form relates one or more parameters to energy values and energy gradients.
Melting Point Suppression In New Lanthanoid(Iii) Ionic Liquids By Trapping Of Kinetic Polymorphs: An In Situsynchrotron Powder Diffraction Study, Anthony S.R. Chesman, Mei Yang, Bert Mallick, Tamsyn M. Ross, Ian A. Gass, Glen B. Deacon, Stuart R. Batten, Anja V. Mudring
Melting Point Suppression In New Lanthanoid(Iii) Ionic Liquids By Trapping Of Kinetic Polymorphs: An In Situsynchrotron Powder Diffraction Study, Anthony S.R. Chesman, Mei Yang, Bert Mallick, Tamsyn M. Ross, Ian A. Gass, Glen B. Deacon, Stuart R. Batten, Anja V. Mudring
Anja V. Mudring
he inclusion of lanthanoids in ionic liquids (ILs) offers an ideal route to incorporate their unique luminescent and magnetic properties into a bulk solution.1,2 However, lanthanoid compounds often exhibit a poor solubility in commonly used ILs because the IL anions are typically very weakly coordinating, prohibiting the simple dissolution of a lanthanoid salt by complexation to any beneficial extent.2 One strategy used to achieve high lanthanoid concentrations is to incorporate the lanthanoid cation directly into an anion that will form ILs.3 This is best accomplished by employing a ligand which readily coordinates to a lanthanoid atom and possesses properties, such …
Phosphate Protected Fluoride Nano-Phosphors, Joanna Cybinska, Chantal Lorbeer, Anja V. Mudring
Phosphate Protected Fluoride Nano-Phosphors, Joanna Cybinska, Chantal Lorbeer, Anja V. Mudring
Anja V. Mudring
A fast and easy 2-in-1 step microwave reaction procedure to phosphate coated nanofluorides allows for the formation of phosphate protected fluoride nanoparticles from simple lanthanide precursors in ionic liquids. The phosphate shell efficiently prevents the fluoride particle from decomposition in an atmosphere (containing oxygen and water) at elevated temperatures.
Lanthanide Coordination Polymers With Tetrafluoroterephthalate As A Bridging Ligand: Thermal And Optical Properties, Christiane Seidel, Chantal Lorbeer, Joanna Cyninska, Anja V. Mudring, Uwe Ruschewitz
Lanthanide Coordination Polymers With Tetrafluoroterephthalate As A Bridging Ligand: Thermal And Optical Properties, Christiane Seidel, Chantal Lorbeer, Joanna Cyninska, Anja V. Mudring, Uwe Ruschewitz
Anja V. Mudring
Seven new coordination polymers ∞2[Ln(tfBDC)(NO3)(DMF)2]·DMF (Ln3+ = Ce, Pr, Nd, Sm, Dy, Er, Yb) with the perfluorinated linker ligand tetrafluoroterephthalate (tfBDC2−) have been synthesized. Their crystal structures consist of layers (44 nets) weakly bound by van der Waals interactions. In addition, differential thermal analysis/thermogravimetry (DTA/TG) curves, as well as absorption and emission spectra, have been recorded for all compounds.
Betaine Chloride-Betaine Tetrachloridoferrate(Iii)—An Ionic Liquid Related Crystal Structure Governed By The Pearson Concept, Anja V. Mudring, Tobias Backer
Betaine Chloride-Betaine Tetrachloridoferrate(Iii)—An Ionic Liquid Related Crystal Structure Governed By The Pearson Concept, Anja V. Mudring, Tobias Backer
Anja V. Mudring
The first betaine chloride tetrachloroidoferrate(III) double salt, (Hbet)2Cl[FeCl4] = (Hbet)Cl·(Hbet)[FeCl4], was obtained from a solution of betaine hydrochloride (HbetCl) and FeCl3∙6 H2O in water. The crystal structure (orthorhombic, Pbcm, a = 6.2717(13), b = 12.841(3), c = 25.693(5) Å, Z = 4) is characterized by layers of tetrachloridoferrate(III) anions separated by chloride-bridged, H-bond mediated cationic (Hbet) dimers. The hydrogen bonding network in the crystal structure follows the Pearson HSAB (hard acid-soft base) concept: According to the Pearson concept, the chloride anions show high affinity to the carboxyl group (hard acid and base), and the tetrachloroidoferrate(III) anion preferentially interacts with the …
Ultrasound-Assisted Synthesis Of Mesoporous Β-Ni(Oh)2 And Nio Nano-Sheets Using Ionic Liquids, Tarek Alammar, Osama Shekhah, Jonas Wohlgemuth, Anja V. Mudring
Ultrasound-Assisted Synthesis Of Mesoporous Β-Ni(Oh)2 And Nio Nano-Sheets Using Ionic Liquids, Tarek Alammar, Osama Shekhah, Jonas Wohlgemuth, Anja V. Mudring
Anja V. Mudring
Via a facile ultrasound synthesis from nickel acetate and sodium hydroxide with ionic liquids as the solvent and template it is possible to obtain nano-β-Ni(OH)2 of various dimensionalities depending on the reaction conditions with the ionic liquid (IL) being the most important factor. Scanning electron microscopy (SEM) imaging showed β-Ni(OH)2 to form as nanosheets, nanorods and nanospheres depending on the IL. ILs with strong to moderate hydrogen bonding capability like [C3mimOH][Tf2N] (1-(3-hydroxypropyl)-3-methylimidazolium bis(trifluoromethanesulfonylamide)), [C4mim][Tf2N] (1-butyl-3-methylimidazolium bis(trifluoromethanesulfonylamide)) and [Edimim][Tf2N] (1-ethyl-2,3-diemethylimidazolium bis(trifluoromethanesulfonylamide)) lead to the formation of nanosheets whilst [Py4][Tf2N] (butyl-pyridinium bis(trifluoromethanesulfonylamide)) leads to nanoparticles and [N1888][Tf2N] (methyltrioctylammonium bis(trifluoromethanesulfonylamide)) to nanorods. Subsequent …
Direct Pore‐Level Observation Of Permeability Increase In Two‐Phase Flow By Shaking, Igor A. Beresnev, William Gaul, R. Dennis Vigil
Direct Pore‐Level Observation Of Permeability Increase In Two‐Phase Flow By Shaking, Igor A. Beresnev, William Gaul, R. Dennis Vigil
R. Dennis Vigil
Increases in permeability of natural reservoirs and aquifers by passing seismic waves have been well documented. If the physical causes of this phenomenon can be understood, technological applications would be possible for controlling the flow in hydrologic systems or enhancing production from oil reservoirs. The explanation of the dynamically increased mobility of underground fluids must lie at the pore level. The natural fluids can be viewed as two-phase systems, composed of water as the wetting phase and of dispersed non-wetting globules of gas or organic fluids, flowing through tortuous constricted channels. Capillary forces prevent free motion of the suspended non-wetting …
Thickness Of Residual Wetting Film In Liquid-Liquid Displacement, Igor A. Beresnev, William Gaul, R .Dennis Vigil
Thickness Of Residual Wetting Film In Liquid-Liquid Displacement, Igor A. Beresnev, William Gaul, R .Dennis Vigil
R. Dennis Vigil
Core-annular flow is common in nature, representing, for example, how streams of oil, surrounded by water, move in petroleum reservoirs. Oil, typically a nonwetting fluid, tends to occupy the middle (core) part of a channel, while water forms a surrounding wall-wetting film. What is the thickness of the wetting film? A classic theory has been in existence for nearly 50 years offering a solution, although in a controversial manner, for moving gas bubbles. On the other hand, an acceptable, experimentally verified theory for a body of one liquid flowing in another has not been available. Here we develop a hydrodynamic, …
Forced Instability Of Core-Annular Flow In Capillary Constrictions, Igor A. Beresnev, William Gaul, R. Dennis Vigil
Forced Instability Of Core-Annular Flow In Capillary Constrictions, Igor A. Beresnev, William Gaul, R. Dennis Vigil
R. Dennis Vigil
Instability of fluid cylinders and jets, a highly nonlinear hydrodynamic phenomenon, has fascinated researchers for nearly 150 years. A subset of the phenomenon is the core-annular flow, in which a non-wetting core fluid and a surrounding wall-wetting annulus flow through a solid channel. The model, for example, represents the flow of oil in petroleum reservoirs. The flow may be forced to break up when passing through a channel’s constriction. Although it has long been observed that the breakup occurs near the neck of the constriction, the exact conditions for the occurrence of the forced breakup and its dynamic theory have …
A Large Deformation, Rotation-Free, Isogeometric Shell, D. J. Benson, Y. Bazilevs, Ming-Chen Hsu, T. J. R. Hughes
A Large Deformation, Rotation-Free, Isogeometric Shell, D. J. Benson, Y. Bazilevs, Ming-Chen Hsu, T. J. R. Hughes
Ming-Chen Hsu
Conventional finite shell element formulations use rotational degrees of freedom to describe the motion of the fiber in the Reissner–Mindlin shear deformable shell theory, resulting in an element with five or six degrees of freedom per node. These additional degrees of freedom are frequently the source of convergence difficulties in implicit structural analyses, and, unless the rotational inertias are scaled, control the time step size in explicit analyses. Structural formulations that are based on only the translational degrees of freedom are therefore attractive. Although rotation-free formulations using C0 basis functions are possible, they are complicated in comparison to their C1 …
Ionic Liquids As Crystallization Media: Weakly-Coordinating Anions Do Coordinate In 1∞[Eu(Otf)3(Ch3cn)3], Sifu Tang, Anja V. Mudring
Ionic Liquids As Crystallization Media: Weakly-Coordinating Anions Do Coordinate In 1∞[Eu(Otf)3(Ch3cn)3], Sifu Tang, Anja V. Mudring
Anja V. Mudring
Tris(acetonitrile)tris(trifluoromethanesulfonato)-europium(III), 1∞[Eu(OTf)3(CH3CN)3], is the first structurally characterized Ln(OTf)3-solvate where triflate is still in the coordination sphere of the Ln(III) cation and not substituted by solvate molecules. This fact is attributed to the unique crystallization conditions that an ionic liquid provides: 1∞[Eu(OTf)3(CH3CN)3] was obtained from a solution of europium(III) triflate, Eu(OTf)3, with acetonitrile in the ionic liquid [C4py][OTf] (1-butylpyridinium triflate). The crystal structure (triclinic, P1̅ (no. 2), a = 5.734(1) Å, b = 10.500(2) Å, c = 19.088(4) Å, α = 98.09(3)°, β = 93.79(3)°, γ = 91.46(3)°, V = 1134.5(4) Å3, Z = 2, R1 for 4388 reflections with Io …
Efficient Quantum Cutting In Hexagonal Nagdf4:Eu3+ Nanorods, Pushpal Ghosh, Sifu Tang, Anja V. Mudring
Efficient Quantum Cutting In Hexagonal Nagdf4:Eu3+ Nanorods, Pushpal Ghosh, Sifu Tang, Anja V. Mudring
Anja V. Mudring
An ionic liquid (IL) assisted solvothermal method is employed to prepare single phase, oxygen free, hexagonal NaGdF4:Eu3+ (2 mol%) nanorods with a visible quantum efficiency of 187%. In contrast, for mixed materials containing cubic and hexagonal NaGdF4:Eu3+, the quantum efficiency is much less (127%). Thus, synthesis parameters have to be carefully chosen in order to get the high performance hexagonal material. Not only the influence of the IL but also of the Gd : F ratio during synthesis as well as the temperature were studied. It is found that the IL stabilizes the formation of hexagonal NaGdF4:Eu3+, likewise a fluoride …
Stability And Growth Behavior Of Transition Metal Nanoparticles In Ionic Liquids Prepared By Thermal Evaporation: How Stable Are They Really?, Kai Richter, Alexander Birkner, Anja V. Mudring
Stability And Growth Behavior Of Transition Metal Nanoparticles In Ionic Liquids Prepared By Thermal Evaporation: How Stable Are They Really?, Kai Richter, Alexander Birkner, Anja V. Mudring
Anja V. Mudring
Recently we developed an access to metal- and metal-oxide colloids based on thermal evaporation of metals into ionic liquids (ILs). Here we present systematic studies on the long-time stability of gold and copper nanoparticles (NPs) in different ILs. The influence of metal concentration and temperature on the ripening of the as-prepared gold NPs in different ILs was investigated by transmission electron microscopy (TEM) and UV-vis absorption measurements. Short alkyl chain-length-methyl-imidazolium salts with weakly coordinating perfluorinated counter anions (PF6, BF4 or Tf2N, bis(trifluoromethanesulfonyl)amide) were found to be better stabilizers compared to ILs with cations bearing long alkyl chains (trihexyltetradecylphosphonium, 1-octyl-3-methylimidazolium) and …
Structures, Electronic Properties And Solid State Luminescence Of Cu(I) Iodide Complexes With 2,9-Dimethyl-1,10-Phenanthroline And Aliphatic Aminomethylphosphines Or Triphenylphosphine, Radoslaw Starosta, Malgorzata Puchalska, Joanna Cybinska, Maciej Barys, Anja V. Mudring
Structures, Electronic Properties And Solid State Luminescence Of Cu(I) Iodide Complexes With 2,9-Dimethyl-1,10-Phenanthroline And Aliphatic Aminomethylphosphines Or Triphenylphosphine, Radoslaw Starosta, Malgorzata Puchalska, Joanna Cybinska, Maciej Barys, Anja V. Mudring
Anja V. Mudring
The luminescent complexes of triphenylphosphine and two interesting aminomethylphosphines: P(CH2N(CH2CH2)2NCH3)3 and P(CH2N(CH2CH2)2O)3 with copper(I) iodide and 2,9-dimethyl-1,10-phenanthroline (dmp): [CuI(dmp)PPh3], [CuI(dmp)P(CH2N(CH2CH2)2NCH3)3] and [CuI(phen)P(CH2N(CH2CH2)2O)3] are presented in this work. These complexes were characterized in solution by means of NMR spectroscopy and their structures were crystallographically determined in the solid state. All complexes crystallize as the discrete dimers bound by π-stacking interactions between dmp rings. The coordination geometry about the Cu(I) centre is pseudo-tetrahedral showing small flattening and large rocking distortions. The investigated compounds exhibit intense orange photoluminescence in the solid state (emission peaks at r.t.: λmax = 588–592 nm; τ = 1.7–2.2 …
In-Situ Crystal Growth And Properties Of The Magnetic Ionic Liquid [C2mim][Fecl4], Tobias Backer, Oliver Breunig, Klaus Merz, Vera Vasylyeva, Anja V. Mudring
In-Situ Crystal Growth And Properties Of The Magnetic Ionic Liquid [C2mim][Fecl4], Tobias Backer, Oliver Breunig, Klaus Merz, Vera Vasylyeva, Anja V. Mudring
Anja V. Mudring
[C2mim][FeCl4] behaves like a paramagnetic liquid at room temperature. Specific heat measurements indicate that there is a magnetic ordering below 3.8 K. The released entropy is far from the expected value for a J = 5/2 system, implying that the magnetic state is partly disordered. Full magnetic polarization was reached in fields above 4 T, and the anomaly in the magnetic susceptibility can be fully suppressed in higher B fields. Hence, the suggested magnetic ground state is superparamagnetic. In order to better understand the magnetic nature of this compound, structural investigations were carried out. Raman and IR-spectroscopy as well as …
A New Open-Framework Iron Borophosphate From Ionic Liquids: Kfe[Bp2o8(Oh)], Guangmei Wang, Anja V. Mudring
A New Open-Framework Iron Borophosphate From Ionic Liquids: Kfe[Bp2o8(Oh)], Guangmei Wang, Anja V. Mudring
Anja V. Mudring
A new open-framework iron borophosphate, KFe[BP2O8(OH)], has been obtained by ionothermal synthesis from KH2PO4, FeCl3∙4H2O, H3BO3 and [C4mpyr]Br (1-butyl-1-methylpyrrolidinium bromide). Single-crystal X-ray diffraction analysis shows that KFe[BP2O8(OH)] (monoclinic, P21/c, a = 9.372(2) Å , b = 8.146(2)Å , c = 9.587(2) Å, β = 101.18(3)°, V = 718.0(2)Å3 and Z = 4) has a three-dimensional (3-D) framework structure composed by {Fe(III)O5(OH)} octahedra as well as {BO3(OH)} and {PO4} tetrahedra. As anionic structural sub-unit, KFe[BP2O8(OH)], contains an infinite open-branched {[BP2O8(OH)]4-} chain which is formed by alternating {BO3(OH)} and {PO4} tetrahedra. {Fe(III)O5(OH)} octahedra share common O corners with five phosphate tetrahedra and …
The First Lanthanide Telluride-Bromide: La3te4br, A Valence Compound, Markus Larres, Anja V. Mudring, Gerd Meyer
The First Lanthanide Telluride-Bromide: La3te4br, A Valence Compound, Markus Larres, Anja V. Mudring, Gerd Meyer
Anja V. Mudring
The first ternary lanthanide telluride-bromide La3Te4Br was obtained from a mixture of LaTe and LaBr3 (in the presence of iridium) in a sealed tantalum container at elevated temperatures. The crystal structure (orthorhombic, Pnma, a = 1634.3(2), b = 435.0(1), c = 1426.6(2) pm, Z = 4, R1 (I0 > 2s(I0)) = 0.0349) is built from dicapped trigonal prisms of tellurium and bromine atoms surrounding lanthanum in two different ways. The dicapped trigonal prisms are connected via common edges to a threedimensional structure, in the same fashion as is known for the binary U3Te5. La3Te4Br is a valence compound according to (La3+)3(Te2-)4(Br-) …
Linear Trimeric Hafnium Clusters In Hf0.86(1)I3, Jan Beekhuizen, Anja V. Mudring, Gerd Meyer
Linear Trimeric Hafnium Clusters In Hf0.86(1)I3, Jan Beekhuizen, Anja V. Mudring, Gerd Meyer
Anja V. Mudring
The reduction of hafnium tetraiodide, HfI4, with aluminum at 600 °C or 850 °C in the presence of a NaI flux resulted in black single crystals of Hf0.86(1)I3. This composition corresponds well to the upper end of the non-stoichiometry range 0.89 ≤ x ≤ 1.00 previously reported for HfxI3. The crystal structure (a = 1250.3(2), c = 1999.6(3) pm, R-3m, Z = 18) is made up of hexagonal closest packed layers of iodide ions. One third of the octahedral holes would be filled as in TiI3 or ZrI3 if it were Hf1.00I3. In Hf0.86(1)I3, one out of six octahedral holes …
(B15c5)Bii3(I2): Molecular Benzo-15-Crown-5―Bii3 Complexes Bridged By Iodine Molecules To Chains, Christoph Fiolka, Mark Richter, Ingo Pantenburg, Anja V. Mudring, Gerd Meyer
(B15c5)Bii3(I2): Molecular Benzo-15-Crown-5―Bii3 Complexes Bridged By Iodine Molecules To Chains, Christoph Fiolka, Mark Richter, Ingo Pantenburg, Anja V. Mudring, Gerd Meyer
Anja V. Mudring
The reaction of bismuth triiodide with iodine and benzo-15-crown-5 in ethanol/dichloromethane yielded red single crystals of (b15c5)BiI3(I2) (monoclinic, P21/c (no. 14), a = 1376.9(1), b = 1172.7(1), c = 1700.2(2) pm, b = 115.197(6), V = 2484.1(4)·106 pm3, Z = 4). Neutral pseudo-octahedral complexes (b15c5)BiI3 are connected by secondary bonding interactions via iodine molecules to chains. Electronic structure calculations of the neutral complex (b15c5)BiI3 reveal that the compound can indeed be described as b15c5 interacting with a molecular BiI3 unit. However, bonding has to be mainly electrostatic as the interactions of the bismuth 6s lone pair with the 2p orbitals …
Europium(Iii) Fluoride Nanoparticles From Ionic Liquids: Structural, Morphological, And Luminescent Properties, Chantal Lorbeer, Joanna Cybinska, Anja V. Mudring
Europium(Iii) Fluoride Nanoparticles From Ionic Liquids: Structural, Morphological, And Luminescent Properties, Chantal Lorbeer, Joanna Cybinska, Anja V. Mudring
Anja V. Mudring
Inorganic luminescent materials (phosphors) find widespread scientific and industrial applications. For potential applications, nanoscale phosphors are favored because of the reduced scattering and the possibility to miniaturize devices. In such materials, the optical behavior is strongly dependent on impurities or defects in the crystal lattice, so that a well-defined reaction protocol with fixed parameters is compulsory to ensure the quality of the obtained material. The fast and facile conversion of europium acetate via microwave radiation with and in different tetrafluoroborate ionic liquids to oxygen-free, hexagonal EuF3 nanoparticles is investigated in detail. The study of the influence of the different reaction …
Structural, Magnetic, And Defect Properties Of Co-Pt-Type Magnetic-Storage Alloys: Density-Functional Theory Study Of Thermal Processing Effects, Aftab Alam, Brent Kraczek, Duane D. Johnson
Structural, Magnetic, And Defect Properties Of Co-Pt-Type Magnetic-Storage Alloys: Density-Functional Theory Study Of Thermal Processing Effects, Aftab Alam, Brent Kraczek, Duane D. Johnson
Duane D. Johnson
Using an optimized-basis Korringa-Kohn-Rostoker-coherent-potential approximation method, we calculate formation enthalpies ΔEf, structural, and magnetic properties of paramagnetic (PM) and ferromagnetic, disordered A1 and ordered L10 CoPt, FePd, and FePt systems that are of interest for high-density magnetic-recording media. To address processing effects, we focus on the point defects that dictate thermal properties and planar defects (e.g., c domain and antiphase boundaries) which can serve as pinning centers for magnetic domains and affect storage properties. We determine bulk Curie (Tc) and order-disorder (To-d) transition temperatures within 4% of observed values, and estimates for nanoparticles. Planar-defect energies γhklx show that the favorable …
Isogeometric Shell Analysis: The Reissner–Mindlin Shell, D. J. Benson, Y. Bazilevs, Ming-Chen Hsu, T.J.R. Hughes
Isogeometric Shell Analysis: The Reissner–Mindlin Shell, D. J. Benson, Y. Bazilevs, Ming-Chen Hsu, T.J.R. Hughes
Ming-Chen Hsu
A Reissner–Mindlin shell formulation based on a degenerated solid is implemented for NURBS-based isogeometric analysis. The performance of the approach is examined on a set of linear elastic and nonlinear elasto-plastic benchmark examples. The analyses were performed with LS-DYNA, an industrial, general-purpose finite element code, for which a user-defined shell element capability was implemented. This new feature, to be reported on in subsequent work, allows for the use of NURBS and other non-standard discretizations in a sophisticated nonlinear analysis framework.
[Ni(Tmen)(Acac)][B(Ph)4] A Probe For The Anion Basicity Of Ionic Liquids, Joanna Bartosik, Anja V. Mudring
[Ni(Tmen)(Acac)][B(Ph)4] A Probe For The Anion Basicity Of Ionic Liquids, Joanna Bartosik, Anja V. Mudring
Anja V. Mudring
An optical basicity scale of various ionic liquids (IL) anions has been determined by UV-Vis absorption spectroscopy. The indicator complex [Ni(tmen)(acac)][B(Ph)4] (tmen = tetramethylethylendiamine, acac = acetylacetonate) shows to be a sensitive probe as the position of the 3A2g(F) → 3T1g(F) absorption maximum of square planar to octahedral Ni2+ shifts distinctly depending on the electron donor ability of the respective ionic liquid anion. If the Lewis basicity of the anion becomes stronger a change to a tetrahedral coordination around Ni2+ is observed. Here the 3T1(F) → 3T2(F) and 3T1(F) → 3T1(P) transitions are helpful for monitoring the IL anion basicity. …