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
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]
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]
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
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
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 eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than 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
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
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
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
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
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