@article{ReiterHeidbach2014, author = {Reiter, Karsten and Heidbach, Oliver}, title = {3-D geomechanical-numerical model of the contemporary crustal stress state in the Alberta Basin (Canada)}, series = {Solid earth}, volume = {5}, journal = {Solid earth}, number = {2}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1869-9510}, doi = {10.5194/se-5-1123-2014}, pages = {1123 -- 1149}, year = {2014}, abstract = {In the context of examining the potential usage of safe and sustainable geothermal energy in the Alberta Basin, whether in deep sediments or crystalline rock, the understanding of the in situ stress state is crucial. It is a key challenge to estimate the 3-D stress state at an arbitrarily chosen point in the crust, based on sparsely distributed in situ stress data. To address this challenge, we present a large-scale 3-D geomechanical-numerical model (700 km x 1200 km x 80 km) from a large portion of the Alberta Basin, to provide a 3-D continuous quantification of the contemporary stress orientations and stress magnitudes. To calibrate the model, we use a large database of in situ stress orientation (321 S-Hmax) as well as stress magnitude data (981 S-V, 1720 S-hmin and 2 (+11) S-Hmax) from the Alberta Basin. To find the best-fit model, we vary the material properties and primarily the displacement boundary conditions of the model. This study focusses in detail on the statistical calibration procedure, because of the large amount of available data, the diversity of data types, and the importance of the order of data tests. The best-fit model provides the total 3-D stress tensor for nearly the whole Alberta Basin, and allows estimation of stress orientation and stress magnitudes in advance of any well. First-order implications for the well design and configuration of enhanced geothermal systems are revealed. Systematic deviations of the modelled stress from the in situ data are found for stress orientations in the Peace River and the Bow Island Arch as well as for leak-off test magnitudes.}, language = {en} } @article{GholamrezaieScheckWenderothBottetal.2019, author = {Gholamrezaie, Ershad and Scheck-Wenderoth, Magdalena and Bott, Judith and Heidbach, Oliver and Strecker, Manfred}, title = {3-D crustal density model of the Sea of Marmara}, series = {Solid Earth}, volume = {10}, journal = {Solid Earth}, publisher = {Copernicus Publ.}, address = {G{\"o}ttingen}, issn = {1869-9510}, doi = {10.5194/se-10-785-2019}, pages = {785 -- 807}, year = {2019}, abstract = {Abstract. The Sea of Marmara, in northwestern Turkey, is a transition zone where the dextral North Anatolian Fault zone (NAFZ) propagates westward from the Anatolian Plate to the Aegean Sea Plate. The area is of interest in the context of seismic hazard of Istanbul, a metropolitan area with about 15 million inhabitants. Geophysical observations indicate that the crust is heterogeneous beneath the Marmara basin, but a detailed characterization of the crustal heterogeneities is still missing. To assess if and how crustal heterogeneities are related to the NAFZ segmentation below the Sea of Marmara, we develop new crustal-scale 3-D density models which integrate geological and seismological data and that are additionally constrained by 3-D gravity modeling. For the latter, we use two different gravity datasets including global satellite data and local marine gravity observation. Considering the two different datasets and the general non-uniqueness in potential field modeling, we suggest three possible "end-member" solutions that are all consistent with the observed gravity field and illustrate the spectrum of possible solutions. These models indicate that the observed gravitational anomalies originate from significant density heterogeneities within the crust. Two layers of sediments, one syn-kinematic and one pre-kinematic with respect to the Sea of Marmara formation are underlain by a heterogeneous crystalline crust. A felsic upper crystalline crust (average density of 2720 kgm⁻³) and an intermediate to mafic lower crystalline crust (average density of 2890 kgm⁻³) appear to be cross-cut by two large, dome-shaped mafic highdensity bodies (density of 2890 to 3150 kgm⁻³) of considerable thickness above a rather uniform lithospheric mantle (3300 kgm⁻³). The spatial correlation between two major bends of the main Marmara fault and the location of the highdensity bodies suggests that the distribution of lithological heterogeneities within the crust controls the rheological behavior along the NAFZ and, consequently, maybe influences fault segmentation and thus the seismic hazard assessment in the region.}, language = {en} } @article{WiederkehrBousquetZiemannetal.2011, author = {Wiederkehr, Michael and Bousquet, Romain and Ziemann, Martin Andreas and Berger, Alfons and Schmid, Stefan M.}, title = {3-D assessment of peak-metamorphic conditions by Raman spectroscopy of carbonaceous material an example from the margin of the Lepontine dome (Swiss Central Alps)}, series = {International journal of earth sciences}, volume = {100}, journal = {International journal of earth sciences}, number = {5}, publisher = {Springer}, address = {New York}, issn = {1437-3254}, doi = {10.1007/s00531-010-0622-2}, pages = {1029 -- 1063}, year = {2011}, abstract = {This study monitors regional changes in the crystallinity of carbonaceous matter (CM) by applying Micro-Raman spectroscopy to a total of 214 metasediment samples (largely so-called Bundnerschiefer) dominantly metamorphosed under blueschist- to amphibolite-facies conditions. They were collected within the northeastern margin of the Lepontine dome and easterly adjacent areas of the Swiss Central Alps. Three-dimensional mapping of isotemperature contours in map and profile views shows that the isotemperature contours associated with the Miocene Barrow-type Lepontine metamorphic event cut across refolded nappe contacts, both along and across strike within the northeastern margin of the Lepontine dome and adjacent areas. Further to the northeast, the isotemperature contours reflect temperatures reached during the Late Eocene subduction-related blueschist-facies event and/or during subsequent near-isothermal decompression; these contours appear folded by younger, large-scale post-nappe-stacking folds. A substantial jump in the recorded maximum temperatures across the tectonic contact between the frontal Adula nappe complex and surrounding metasediments indicates that this contact accommodated differential tectonic movement of the Adula nappe with respect to the enveloping Bundnerschiefer after maximum temperatures were reached within the northern Adula nappe, i.e. after Late Eocene time.}, language = {en} } @article{HoehnkeJohnson1995, author = {Hoehnke, Hans-J{\"u}rgen and Johnson, K. W.}, title = {3-characters are sufficient for the group determinant}, year = {1995}, language = {en} } @article{Gienow1992, author = {Gienow, Wilfried}, title = {2nd English Studies Conference at the Freie Universit{\"a}t Berlin}, year = {1992}, language = {en} } @article{EvansvanLoonHainichetal.2015, author = {Evans, Chris J. and van Loon, Jacco Th. and Hainich, Rainer and Bailey, M.}, title = {2dF-AAOmega spectroscopy of massive stars in the Magellanic Clouds The north-eastern region of the Large Magellanic Cloud}, series = {Astronomy and astrophysics : an international weekly journal}, volume = {584}, journal = {Astronomy and astrophysics : an international weekly journal}, publisher = {EDP Sciences}, address = {Les Ulis}, issn = {1432-0746}, doi = {10.1051/0004-6361/201525882}, pages = {19}, year = {2015}, abstract = {We present spectral classifications from optical spectroscopy of 263 massive stars in the north-eastern region of the Large Magellanic Cloud. The observed two-degree field includes the massive 30 Doradus star-forming region, the environs of SN1987A, and a number of star-forming complexes to the south of 30 Dor. These are the first classifications for the majority (203) of the stars and include eleven double-lined spectroscopic binaries. The sample also includes the first examples of early OC-type spectra (AA Omega 30 Dor 248 and 280), distinguished by the weakness of their nitrogen spectra and by C IV lambda 4658 emission. We propose that these stars have relatively unprocessed CNO abundances compared to morphologically normal O-type stars, indicative of an earlier evolutionary phase. From analysis of observations obtained on two consecutive nights, we present radial-velocity estimates for 233 stars, finding one apparent single-lined binary and nine (>3 sigma) outliers compared to the systemic velocity; the latter objects could be runaway stars or large-amplitude binary systems and further spectroscopy is required to investigate their nature.}, language = {en} } @article{OstermeyerHeuerMenzel1998, author = {Ostermeyer, Martin and Heuer, Axel and Menzel, Ralf}, title = {27 Watt average output power with 1.2*DL beam quality from a single rod Nd:YAG-Laser with phase conjugating SBS- mirror}, year = {1998}, language = {en} } @article{SchulzeBettBivouretal.2020, author = {Schulze, Patricia S. C. and Bett, Alexander J. and Bivour, Martin and Caprioglio, Pietro and Gerspacher, Fabian M. and Kabakl{\i}, {\"O}zde Ş. and Richter, Armin and Stolterfoht, Martin and Zhang, Qinxin and Neher, Dieter and Hermle, Martin and Hillebrecht, Harald and Glunz, Stefan W. and Goldschmidt, Jan Christoph}, title = {25.1\% high-efficiency monolithic perovskite silicon tandem solar cell with a high bandgap perovskite absorber}, series = {Solar RRL}, volume = {4}, journal = {Solar RRL}, number = {7}, publisher = {John Wiley \& Sons, Inc.}, address = {New Jersey}, pages = {10}, year = {2020}, abstract = {Monolithic perovskite silicon tandem solar cells can overcome the theoretical efficiency limit of silicon solar cells. This requires an optimum bandgap, high quantum efficiency, and high stability of the perovskite. Herein, a silicon heterojunction bottom cell is combined with a perovskite top cell, with an optimum bandgap of 1.68 eV in planar p-i-n tandem configuration. A methylammonium-free FA(0.75)Cs(0.25)Pb(I0.8Br0.2)(3) perovskite with high Cs content is investigated for improved stability. A 10\% molarity increase to 1.1 m of the perovskite precursor solution results in approximate to 75 nm thicker absorber layers and 0.7 mA cm(-2) higher short-circuit current density. With the optimized absorber, tandem devices reach a high fill factor of 80\% and up to 25.1\% certified efficiency. The unencapsulated tandem device shows an efficiency improvement of 2.3\% (absolute) over 5 months, showing the robustness of the absorber against degradation. Moreover, a photoluminescence quantum yield analysis reveals that with adapted charge transport materials and surface passivation, along with improved antireflection measures, the high bandgap perovskite absorber has the potential for 30\% tandem efficiency in the near future.}, language = {en} } @article{StreichBeckenRitter2011, author = {Streich, Rita and Becken, Michael and Ritter, Oliver}, title = {2.5D controlled-source EM modeling with general 3D source geometries}, series = {Geophysics}, volume = {76}, journal = {Geophysics}, number = {6}, publisher = {Society of Exploration Geophysicists}, address = {Tulsa}, issn = {0016-8033}, doi = {10.1190/GEO2011-0111.1}, pages = {F387 -- F393}, year = {2011}, abstract = {Most 2.5D controlled-source electromagnetic (CSEM) modeling algorithms presented to date explicitly consider only sources that are point dipoles oriented parallel or perpendicular to the direction of constant conductivity. This makes simulations of complex source geometries expensive, requiring separate evaluations of many point dipole fields, and thus limits the practical applicability of such schemes for simulating and interpreting field data. We present a novel 2.5D CSEM modeling scheme that overcomes this limitation and permits efficient simulations of sources with general shape and orientation by evaluating fields for the entire source at once. We accommodate general sources by using a secondary field approach, in which primary fields are computed for the general source and a 1D background conductivity model. To carry out the required Fourier transforms between space and wavenumber domain using the same fast cosine and sine transform filters as in conventional algorithms, we split the primary and secondary fields into their symmetric and antisymmetric parts. For complex 3D source geometries, this approach is significantly more efficient than previous 2.5D algorithms. Our finite-difference algorithm also includes novel approaches for divergence correction at low frequencies and EM field interpolation across conductivity discontinuities. We describe the modeling scheme and demonstrate its accuracy and efficiency by comparisons of 2.5D-simulated data with 1D and 3D results.}, language = {en} } @article{KolocourisKochKleinpeteretal.2015, author = {Kolocouris, Antonios and Koch, Andreas and Kleinpeter, Erich and Stylianakis, Ioannis}, title = {2-Substituted and 2,2-disubstituted adamantane derivatives as models for studying substituent chemical shifts and C-H-ax center dot center dot center dot Y-ax cyclohexane contacts-results from experimental and theoretical NMR spectroscopic chemical shifts and DFT structures}, series = {Tetrahedron}, volume = {71}, journal = {Tetrahedron}, number = {16}, publisher = {Elsevier}, address = {Oxford}, issn = {0040-4020}, doi = {10.1016/j.tet.2015.01.044}, pages = {2463 -- 2481}, year = {2015}, abstract = {The complete H-1 and C-13 NMR chemical shifts assignment for various 2-substituted and 2,2-disubstituted adamantane derivatives 1-38 in CDCl3 solution was realized on the basis of NMR experiments combined with chemical structure information and DFT-GIAO (B3LYP/6-31+G(d,p)-GIAO) calculations of chemical shifts in solution. Substituent-induced C-13 NMR chemical shifts (SCS) are discussed. C-H-ax center dot center dot center dot Y-ax contacts are a textbook prototype of steric hindrance in organic chemistry. The nature of these contacts will be further investigated in this work on basis of new adamantane derivatives, which are substituted at C-2 to provide models for 1,4-C-H-ax center dot center dot center dot Y-ax and 1,5-C-H-ax center dot center dot center dot Y-ax contacts. The B3LYP/6-31+G(d,p) calculations predicted the presence of NBO hyperconjugative attractive interactions between C-H-ax and Y-ax groups along C-H-ax center dot center dot center dot Y-ax contacts. The H-1 NMR signal separation, Delta delta(gamma-CH2), reflects the strength of the H-bonded C-H-ax center dot center dot center dot Y-ax contact. (C) 2015 Elsevier Ltd. All rights reserved.}, language = {en} } @article{Schmidt1998, author = {Schmidt, Hans-J{\"u}rgen}, title = {2-dimensional representations of 4-dimensional gravitational waves}, year = {1998}, language = {en} } @article{GonzalesDiazKasperRainer1998, author = {Gonz{\´a}les-Diaz, P. F. and Kasper, Uwe and Rainer, Martin}, title = {2-Dimensional dilatonic gravity from multidimensional Einstein gravity}, year = {1998}, language = {en} } @article{DzambaskiMarkovicKleinpeteretal.2013, author = {Dzambaski, Zdravko and Markovic, Rade and Kleinpeter, Erich and Baranac-Stojanovic, Marija}, title = {2-Alkylidene-4-oxothiazolidine S-oxides - synthesis and stereochemistry}, series = {Tetrahedron}, volume = {69}, journal = {Tetrahedron}, number = {31}, publisher = {Elsevier}, address = {Oxford}, issn = {0040-4020}, doi = {10.1016/j.tet.2013.05.087}, pages = {6436 -- 6447}, year = {2013}, abstract = {A series of 5-unsubstituted and 5-substituted 2-alkylidene-4-oxothiazolidine-S-oxides were synthesized by the sulfur-oxidation with m-CPBA. The stereochemistry of 5-substituted sulfoxides was determined by means of NMR spectroscopy and DFT theoretical calculations. It was found that the thermodynamically less stable anti-isomer was initially formed in the course of the oxidation, but it underwent epimerization to the mixture enriched in the more stable syn-isomer, during the work-up process. The higher stability of syn-isomers is ascribed to the stronger hyperconjugative sigma(C-H)->sigma*(S-O) interaction versus the weaker sigma(C-C)->sigma*(S-O) delocalization in their anti-counterparts and to the existence of intramolecular 1,5-CH center dot center dot center dot C hydrogen bonds.}, language = {en} } @article{StrehmelRexhausenStrauch2010, author = {Strehmel, Veronika and Rexhausen, Hans and Strauch, Peter}, title = {2,2,6,6-Tetramethylpiperidine-1-yloxyl bound to the imidazolium ion by an acetamido group for investigation of ionic liquids}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2009.11.124}, year = {2010}, abstract = {New spin probes bearing the 2,2,6,6-tetramethylpiperidine-1-yloxyl covalently bound to the imidazolium ion via a methylene spacer and an amide group are synthesized. If the anion is bis(trifluoromethylsulfonylimide) instead of iodide, the new spin probe has a similar structure as that of an ionic liquid. Nevertheless, the new spin probes are useful tools to investigate ionic liquids.}, language = {en} } @article{SchmidtRiemerKarras2013, author = {Schmidt, Bernd and Riemer, Martin and Karras, Manfred}, title = {2,2 '-Biphenols via protecting group-free thermal or microwave-accelerated suzuki-miyaura coupling in water}, series = {The journal of organic chemistry}, volume = {78}, journal = {The journal of organic chemistry}, number = {17}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/jo401398n}, pages = {8680 -- 8688}, year = {2013}, abstract = {User-friendly protocols for the protecting group-free synthesis of 2,2'-biphenols via Suzuki-Miyaura coupling of o-halophenols and o-boronophenol are presented. The reactions proceed in water in the presence of simple additives such as K2CO3, KOH, KF, or TBAF and with commercially available Pd/C as precatalyst. Expensive or laboriously synthesized ligands or other additives are not required. In the case of bromophenols, efficient rate acceleration and short reaction times were accomplished by microwave irradiation.}, language = {en} } @article{KammerKellingBaieretal.2009, author = {Kammer, Stefan and Kelling, Alexandra and Baier, Heiko and Mickler, Wulfhard and Dosche, Carsten and Rurack, Knut and Kapp, Andreas and Lisdat, Fred and Holdt, Hans-J{\"u}rgen}, title = {2,11-dialkylated 1,12-diazaperylene copper(I) complexes : first supramolecular column assemblies by pi-pi stacking between homoleptic tetrahedral metal complexes, exhibiting low-energy MLCT transitions}, issn = {1434-1948}, doi = {10.1002/ejic.200900695}, year = {2009}, abstract = {2,11-Dialkylated 1,12-diazaperylenes (alkyl = Me, Et, iPr) dmedap, detdap and dipdap have been synthesized by reductive cyclization of 3,3-dialkylated 1,1-biisoquinolines 3a-c, resulting in the first copper(I) complexes of a large- surface ligand. The new copper(I) complexes show low-energy MLCT absorptions unprecedented for bis(-diimin)copper(I) complexes. The solid structures of the complexes[Cu(dipdap)2]BF4·CH2Cl2·1.5H2O, [Cu(dipdap)2]OTf·CH2Cl2, [Cu(dipdap)2]I·C2H4Cl2·THF·2H2O, [Cu(dmedap)2]OTf and [Cu(dipdap)2]AQSO3·H2O (AQSO3 = sodium 9,10-dihydro-9,10-dioxo-2- anthracenesulfonate) are reported. In [Cu(dipdap)2]BF4·CH2Cl2·1.5H2O, each copper(I) complex cation interacts with two others by - stacking interactions forming a novel supramolecular column structural motif running along the crystallographic c axis. In the crystalline compound [Cu(dipdap)2]AQSO3·H2O, aggregation between two complex cations and two additional anions by - stacking interactions is observed, leading to a tetrameric assembly. Furthermore, the three complex compounds [Cu(L)2]BF4 (L = dmedap, detdap, dipdap) were tested for sensory applications in aqueous buffer solutions in electrochemical studies of the complex immobilized on glassy carbon electrodes.}, language = {en} } @article{DzhunushalievSchmidt1999, author = {Dzhunushaliev, Vladimir and Schmidt, Hans-J{\"u}rgen}, title = {2+2-decomposable solutions of weyl gravity}, year = {1999}, language = {en} } @article{SchreiberHosemannBeuermann2011, author = {Schreiber, Ulrike and Hosemann, Benjamin and Beuermann, Sabine}, title = {1H,1H,2H,2H-Perfluorodecyl-Acrylate-Containing block copolymers from ARGET ATRP}, series = {Macromolecular chemistry and physics}, volume = {212}, journal = {Macromolecular chemistry and physics}, number = {2}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1022-1352}, doi = {10.1002/macp.201000307}, pages = {168 -- 179}, year = {2011}, abstract = {Block copolymers of 1H,1H,2H,2H-perfluorodecyl acrylate (AC8) were obtained from ARGET ATRP. To obtain block copolymers of low dispersity the PAC8 block was synthesized in anisole with a CuBr(2)/PMDETA catalyst in the presence of tin(II) 2-ethylhexanoate as a reducing agent. The PAC8 block was subsequently used as macroinitiator for copolymerization with butyl and tert-butyl acrylate carried out in scCO(2). To achieve catalyst solubility in CO(2) two fluorinated ligands were employed. The formation of block copolymers was confirmed by size exclusion chromatography and DSC.}, language = {en} } @article{StarkeKochHoldtetal.1995, author = {Starke, Ines and Koch, Andreas and Holdt, Hans-J{\"u}rgen and Kleinpeter, Erich}, title = {1H, 13C, and 15N NMR study of the solution structure of metabridged bis(benzo-15-crown-5-ether)s}, year = {1995}, language = {en} } @article{HilfertSarodnickKempteretal.1998, author = {Hilfert, Liane and Sarodnick, Gerhard and Kempter, Gerhard and Kleinpeter, Erich}, title = {1H, 13C and 15 N NMR study and molecular modelling of 2,3- disubstituted quinoxalines with sterically hinderered aromatic and heteroaromatic substituents}, year = {1998}, language = {en} }