A5019320966- Photorefractive and Nonlinear Optics
- Crystal Structures and Properties
- Inorganic Chemistry and Materials
- Ferroelectric and Piezoelectric Materials
- Microwave Dielectric Ceramics Synthesis
- Inorganic Fluorides and Related Compounds
- Photonic and Optical Devices
- Optical and Acousto-Optic Technologies
- Synthesis and characterization of novel inorganic/organometallic compounds
- Metal-Organic Frameworks: Synthesis and Applications
- Chemical Synthesis and Characterization
- Advanced Condensed Matter Physics
- Cardiac electrophysiology and arrhythmias
- Surface and Thin Film Phenomena
- Solid-state spectroscopy and crystallography
- Asymmetric Synthesis and Catalysis
- Metal and Thin Film Mechanics
- Atrial Fibrillation Management and Outcomes
- Glass properties and applications
- Organophosphorus compounds synthesis
- Nuclear materials and radiation effects
- Layered Double Hydroxides Synthesis and Applications
- Plasma Applications and Diagnostics
- Luminescence Properties of Advanced Materials
- Axial and Atropisomeric Chirality Synthesis
Justus-Liebig-Universität Gießen
1992-2024
Otto-von-Guericke University Magdeburg
2021
University Hospital Magdeburg
2020
Universität Greifswald
2011
Duke University
1985-1987
Newberry College
1978
Clausthal University of Technology
1976
The temperature and oxygen partial pressure (pO2) dependent electrical conductivity of LiNbO3, LiTaO3, LiNb1-xTaxO3 (LNT) solid solutions up to 900 °C is presented. found be isotropic about 700 °C. Different Nb/Ta ratios do not affect activation energies at temperatures below 600 °C, which suggests an identical conduction mechanism, namely the migration Li ions by means vacancies. Above this temperature, noticeable deviations in Nb rich samples emerge due strongly increasing electronic...
Specific heat capacity measurements by differential scanning calorimetry (DSC) of single crystals solid solutions LiNbO3 and LiTaO3 are reported compared with corresponding ab initio calculations, the aim to investigate variation ferroelectric Curie temperature as a function composition. For this purpose, these were grown Czochralski pulling along c-axis. Elemental composition Nb Ta was investigated using XRF analysis, small samples homogeneous well known used for DSC measurements. We...
The ferroelectric to paraelectric phase transition in ${\mathrm{LiTaO}}_{3}$ and pure as well Mg-doped ${\mathrm{LiNbO}}_{3}$ is investigated theoretically by atomistic calculations the framework of density functional theory, experimentally calorimetry electrical conductivity measurements. First-principles models within stochastic self-consistent harmonic approximation (SSCHA) allow consider anharmonic effects thus obtain a realistic estimate Curie temperature ${T}_{C}$ both ferroelectrics....
Among the class of ferroelectric crystals, lithium-niobate-tantalate (LiNb1-xTaxO3) system attracts growing attention for applications in field nonlinear optics, functional electronics and piezoelectrics. The self-diffusion ionic constituents, especially Li, is important overall electric conductivity. aim this investigation to figure out how Li diffusion lithium niobate-tantalate solid solution crystals behaves as a function Ta content. Specially grown LiNb1-xTaxO3 single with different...
${\mathrm{LiNb}}_{1\ensuremath{-}x}{\mathrm{Ta}}_{x}{\mathrm{O}}_{3}$ solid solutions are investigated from first principles and by optical spectroscopy. The ground- excited-state properties of the modeled within density functional theory as a function Ta concentration using special quasirandom structures spanning entire composition range between ${\mathrm{LiNbO}}_{3}$ ${\mathrm{LiTaO}}_{3}$. Deviations Vegard behavior predicted for lattice parameters, heat capacity, electronic band gap,...
We propose a new method for the classification task of distinguishing atrial fibrillation (AFib) from regular tachycardias including flutter (AFlu) based on surface electrocardiogram (ECG). Recently, many approaches an automatic cardiac arrhythmia were proposed and to our knowledge none them can distinguish between these two. discuss reasons why deep learning may not yield satisfactory results this task. generate clinically interpretable features using mathematical optimization subsequent...
Abstract Erstmals wurden RbNa 2 NiO , KNa Na 3 CoO und K dargestellt [RbNa : + Rb O, Rb:Ni = 1,8:1, 600°C, 20 d, Nickelbombe; K:Ni O CoO, Na:Co 8,8:1, 500°C, Cobaltbombe; K:Co 4,4:1, 550°C, Cobaltbombe]. Nach Einkristalldaten weisen Cobalt wie Nickel die Oxydationsstufe 1 auf [jeweils Vierkreisdiffraktometer mit MoK α ‐Strahlung; AED 2, alle 163 I o (hkl), R 3,4%, w 1,9%, I4/mmm, a 461,7(1), c 973,6(3) pm, Z 2; 341 5,6%, 3,5%, Cmma, 048,5(3), b 626,8(1), 621,9(1) 4; PW 100, 517 aus 568 2,9%,...
Abstract K 3 [FeO 2 ] wurde erstmals in Form granatroter Einkristalle durch 40tägiges Tempern von 6 CdO 4 und (molares Verhältnis vor dem Verreiben 1:1,16) verschlossenen Fe‐Zylindern bei 450°C dargestellt. Ebenfalls „Reaktion mit der Gefäßwand”︁ wurden isotype, gleichfarbene [NiO (500°C, 49 d) Ni‐Zylindern erhalten. Die Strukturaufklärung mittels Vierkreisdiffraktometer (K ]: MoK α , 731 I o (hkl), R = 5,76%, w 5,33%, 755 8,70%, 4,25%.) verweist auf die beiden zueinander enantiomorphen...
Laser-induced fluorescence spectroscopy (LIF) was applied to measure absolute densities of the first metastable state in capacitively coupled rf discharges at 13.56 MHz. The transferred B 3 Π g , v = with a dye laser 687.44 nm and transition observed 762 nm. time-depending LIF signal investigated effective lifetime determined by eliminating delay due photomultiplier circuit. density calibration done comparison Rayleigh scattering wavelength 687 Therewith, axial profiles were measured their...
Lithium niobate (LNO) and lithium tantalate (LTO) see widespread use in fundamental research commercial technologies reaching from electronics over classical optics to integrated quantum communication. The mixed crystal system (LNT) allows for the dedicate engineering of material properties by combining advantages two parental materials LNO LTO. Vibrational spectroscopies such as Raman spectroscopy or (Fourier transform) infrared (IR) are vital techniques provide detailed insight into...
Abstract The first phosphines based on the benzo‐7‐phosphanorbornene system have been prepared and found to extremely deshielded 31 P nuclei. phosphine with a P‐ tert ‐butyl group gives most downfield value (δ +152.5) ever recorded for tertiary phosphine. lone‐pair orientation in controls magnitude of 2 J (PC) 3 (PC), these effects were used determine stereochemical features phosphines. These compounds formed by HSiCl pyridine reduction Diels—Alder adducts isophosphindole oxides...
Abstract Durch „Reaktion mit der Gefäßwand”︁ von äquimolaren Gemengen aus K 2 O und CdO in verschlossenen Co‐Bomben entstanden während 73 d bei 450°C dunkelrote Einkristalle CoO . Nach Strukturaufklärung mittels Vierkreisdiffraktometer (MoK α , alle 1 567 I o ( hkl ) zur Verfeinerung, R = 3,25%, w 2,67%) liegt eine monokline Elementarzelle vor. Strukturbestimmendes Merkmal sind planare, dimere [Co 4 ] 4− ‐Einheiten, wie sie analog Rb 10 [2] vorliegen. Der Madelunganteil Gitterenergie, MAPLE,...
Abstract Tiefdunkelrote Einkristalle von CsK 2 [CoO ] entstanden durch „Reaktion mit der Gefäßwand”︁ vorgetempertem Cs K Cd 3 O 5 in verschlossenen Co‐Bomben bei 500°C während 48 d. Die Strukturaufklärung mittels Vierkreisdiffraktometer (MoK α , alle 147 symmetrieunabhängigen I o ( hkl ) zur Verfeinerung, R = 3,42%, w 2,24%) belegt die strukturelle Analogie zu RbNa [NiO [2], dem ersten quaternären Oxoniccolat(I) Alkalimetalle. Gitterkonstanten nach Pulverdaten (Guinier‐Simon) betragen:...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCarbon-carbon bond cleavage during silane reductions of the dimer 2-phenylisophosphindole oxideLouis D. Quin and F. Christian BernhardtCite this: J. Org. Chem. 1986, 51, 16, 3235–3237Publication Date (Print):August 1, 1986Publication History Published online1 May 2002Published inissue 1 August 1986https://pubs.acs.org/doi/10.1021/jo00366a041https://doi.org/10.1021/jo00366a041research-articleACS PublicationsRequest reuse permissionsArticle...
Abstract Erstmals wurde K 10 [Co 4 O 9 ] in Form dunkelroter Einkristalle durch „Reaktion mit der Gefäßwand”︁ beim Tempern inniger Gemenge von KO 0,48 CdO (molares Verhältnis 2,7:1, 73 d, 450°C) verschlossenen Co‐Bomben dargestellt. Die Strukturaufklärung mittels Vierkreisdiffraktometer (Mo α , 2 996 I o (hkl), R = 5,20%, w 3,03%) bestätigt die strukturelle Analogie zu Na [2]. kristallisiert triklin (Raumgruppe P 1 ) a 667,84(5) pm, b 917,91(9) c 908,49(7) 119,400(7)°, β 90,851(7)°, γ...
LiNb$_{1-x}$Ta$_x$O$_3$ solid solutions are investigated from first principles and by optical spectroscopy. The ground- excited-state properties of the modelled within density functional theory as a function Ta concentration using special quasirandom structures spanning entire composition range between LiNbO$_3$ LiTaO$_3$. Deviations Vegard behavior predicted for lattice parameters, heat capacity, electronic bandgap, consequently absorption edge. latter is measured crystals different low...
The ferroelectric to paraelectric phase transition in LiTaO$_3$ and pure as well Mg doped LiNbO$_3$ is investigated theoretically by atomistic calculations the framework of density functional theory, experimentally calorimetry electrical conductivity measurements. First principles models within stochastic self-consistent harmonic approximation (SSCHA) allow consider anharmonic effects thus obtain a realistic estimate Curie temperature $T_C$ both ferroelectrics. \textit{Ab initio} molecular...
Lithium niobate (LNO) and lithium tantalate (LTO) see widespread use in fundamental research commercial technologies reaching from electronics over classical optics to integrated quantum communication. In recent years, the mixed crystal system (LNT) allows for dedicate engineering of material properties by combining advantages two parental materials LNO LTO. Vibrational spectroscopies such as Raman spectroscopy or (Fourier transform) infrared are vital techniques provide detailed insight...
Lithium niobate‐lithium tantalate solid solutions are new piezoelectric crystals that enable to combine the advantages of their edge compounds with respect high thermal stability lithium and Curie temperature niobate. This study aims determine acoustic losses bulk resonators varying Nb/Ta ratios correlation charge transport at temperatures up 900 °C reduced oxygen partial pressures. Techniques such as resonant spectroscopy contactless ringdown used losses. Further, electrical conductivity is...
The structural, thermal, electronic, and optical properties of different WO3 polymorphs are calculated from first principles. Based on density functional theory the quasi-harmonic approximation, thermal expansion coefficient specific heat capacity as a function temperature modeled. Similar trends observed for all phases, with only slight dependence crystal symmetry. dielectric function, refractive index, absorption using an efficient combination G0W0 time-dependent perturbation in long-range...
Abstract Durch 48tägiges Tempern von Rb 6 CdO 4 in verschlossenen Co‐Zylindern bei 500°C wurde erstmals ein gemischt‐valentes Oxid des ein‐ und zweiwertigen Cobalts Form schwarzroten Einkristallen dargestellt. Die Strukturaufklärung mittels Vierkreisdiffraktometer (zwei Messungen: MoK α : 2 145 818 I o (hkl), R = 9,85%, w 5,93% AgK 1 813 007 9,46%, 6,51%) belegt die Raumgruppe P . Gitterkonstanten nach Pulverdaten sind a 696,4(1) pm, b 922,2(3) c 958,9(3) pm , 117,99(2)°, β 89,96(2)°, γ...
Abstract Rb 6 [Fe 2 O 5 ] und K wurden erstmals durch Tempern inniger Gemenge von “Rb CdO 4 ” mit (im Verhältnis 1 : 1,1) bzw. KO 0,48 5,9 1) in verschlossenen Fe‐Zylindern Form roten Einkristallen erhalten. Die Strukturaufklärung (Vierkreisdiffraktometerdaten, ]: Ag α , 720 220 I o (hkl), R = 9,68%, w 6,09%; Mo 214 3,20%, 2,48%) belegt die Raumgruppe C2/m. a 718,9 pm, b 1183,1 c 695,4 β 95,05°, Z 2. 691,21 142,78 665,50 93,82°, Zum ersten Male wird bei derartigen Ferraten eine deutlich...
Catheter ablation of right ventricular outflow tract arrhythmias from above the pulmonary valve is being increasingly reported.