138 research outputs found

    The Crystal Structure of Hexa-μ-chloro-μ4- oxo-tetrakis [hexamethylenetetraminecopper- (II)], [Cu4Cl6O(C6H12N4)4], a Copper(II) Complex with a Structure Related to that of Beryllium Oxoacetate

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    By reaction of solutions of CuCl2·2H2O and hexamethylenetetramine, C6H12N4, in acetone, a complex [Cu4Cl6O(C6H12N4)] could be obtained as single crystals. An X-ray analysis shows that the complex has a structure related to that of basic beryllium acetate. An oxygen atom is tetrahedrally surrounded by four cop-per atoms which, together with six chlorine atoms, form an adamantane-like core. Each copper atom is bonded via a nitrogen atom to a hexamethylenetetramine molecule

    Metal Complexes with Hexamethylenetetramine as a Ligand, VI [1J Crystal Structure of Bis-hexamethylenetetramine-bisisocyanatocopper(II), [Cu(NCO)2(C6Hl2N4)2]

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    Crystals of the complex [Cu(NCO)2(C6Hi2N4)2] could be obtained by reaction of copper- (II)nitrate, hexamethylenetetramine, and KNCO in CHCI3 as a solvent. The crystals are triclinic, space group Cl, Z = 4, a = 1373.1(9), b = 2083.1(9), c = 642.6(3) pm, a = 91.05(4), β = 90.54(6), y = 107.39(6)°. The copper atom is bonded to two terminal cyanato groups via the nitrogen atoms, and to two liexamethylentetramine molecules. In the solid state the coordination of the copper atom is, however, tetragonal pyramidal, because there is an additional, rather long bond to one of the hexamethylenetetramine molecules of the neighbouring complex unit, resulting in the formation of chains

    X-ray Structural Analysis and Vibrational Spectra of Trisulfurdinitrogendioxide, S3N2O2 [1]

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    A redetermination of the crystal and molecular structure of the chain-like molecule S(NSO)2 resulted in the following molecular parameters: d(SO) = 146.5(2), d(S = N) = 153.4(2), d(S-N) = 165.7(2) pm, bond angles OSN = 117.5(1)°, SNS = 123.6(2)°, and NSN = 97.2(1)°, torsion angles OSNS = -0.3(2)°, and SNSN = -177.7(2)° (molecular symmetry C2). Infrared and Raman spectra of S(NSO)2 are reported and assigned; there is no evidence for conformational changes on dissolution of crystalline S(NSO)2

    Crystal Structure and Mossbauer Studies of the Lithium Hexacyanoferrate(III)-Hexamethylenetetramine Adduct Li3[Fe(CN)6] · 2C6H12N4 · 5H2O

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    Crystals of the adduct Li3[Fe(CN)6] · 2C6H12N4-5H2O are orthorhombic, space group I2mm, Z = 2, a = 909.4(5), b = 1046.1(5), c = 1455.8(5) pm. The structure may be regarded as a packing of Fe(CN)6 octahedra and hexamethylenetetramine molecules. The lithium ions are coordinated to nitrogen atoms of both groups and to water molecules. Mossbauer spectra have been recorded for the temperature range between 290 K and 77 K. At all temperatures the spectra show two doublets with nearly identical isomer shifts but different quadrupole splittings, thus indicating the presence of two kinds of hexacyanoferrate(III) ions with slightly different distortions of the ligand spheres around the Fe atoms. The effect is discussed on the assumption of a statistical distribution of one of the lithium ions

    Innovationen im Spezialtiefbau : Fachseminar am 05. Dezember 2013 an der Technischen Universität Berlin

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    Zugleich gedruckt erschienen im Universitätsverlag der TU Berlin unter der ISBN 978-3-7983-2663-7. - ISSN 1610-5648Ganz in der Tradition gemeinsamer Fachseminare von Wissenschaft und Bauwirtschaft sollen mit dem Thema „Innovationen im Spezialtiefbau“ Erkenntnisse über neue Bauverfahren, technische Herausforderungen und Lösungen vermittelt werden. Am 05.12.2013 wurden auf dem Fachseminar am Institut für Bauingenieurwesen der TU Berlin in Expertenvorträgen mit engem Praxisbezug die neuesten Entwicklungen im Spezialtiefbau, bemerkenswert innovative sowie internationale Projektbeispiele vorgestellt und diskutiert. Die Veranstaltung setzt dabei neue Akzente in der branchenweit wie auch öffentlich diskutierten Nachhaltigkeitsbetrachtung und gibt den Anstoß für weitere jährlich stattfindende Fachseminare an der TU Berlin zusammen mit dem InnovationsZentrum Bau Berlin Brandenburg und ihren Partnern aus Forschung und Praxis

    Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

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    A measurement of the cosmic-ray spectrum for energies exceeding 4×10184{\times}10^{18} eV is presented, which is based on the analysis of showers with zenith angles greater than 6060^{\circ} detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above 5.3×10185.3{\times}10^{18} eV, the "ankle", the flux can be described by a power law EγE^{-\gamma} with index γ=2.70±0.02(stat)±0.1(sys)\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)} followed by a smooth suppression region. For the energy (EsE_\text{s}) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find Es=(5.12±0.25(stat)1.2+1.0(sys))×1019E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19} eV.Comment: Replaced with published version. Added journal reference and DO

    Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

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    The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

    Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

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    We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file

    Event-by-event reconstruction of the shower maximum XmaxX_{\mathrm{max}} with the Surface Detector of the Pierre Auger Observatory using deep learning

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