Zur Berechnung der aerodynamischen Koeffizienten von Rotationskörpern mit Tragflächen im Überschallbereich

Riassunto I metodi di calcolo presentati daPitts et al. [1] vengono estesi, previa considerazione dei vortici della fusoliera secondoAllen ePerkins [2] e del loro effetto sulle superfici portanti, ad angoli di attacco di media grandezza e applicati ad una serie di razzi in regime supersonico. Il confronto dei risultati teorici con le corrispondenti misurazioni in soffieria mostra che il punto di attacco della forza normale risultante non può essere calcolato con soddisfacente precisione se la fusoliera si estende per un lungo tratto dietro le superfici portanti. Ricerche condotte dall'autore indicano in base ai risultati finora ottenuti, che il calcolo di combinazioni fusoliera-ali può esser migliorato con mezzi relativamente semplici. Una pubblicazione completa è in preparazione.

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Vorgetragen an der Tagung der Schweizerischen Physikalischen Gesellschaft am 4. Mai 1963 in Bern.     

A study of the reactions γp→ωp and γp→ωp and γp→ωΔ+

The differential and total corss sections and the decay density matrix elements have been measured for the reactions, γp→ωp and γp→ωΔ⁺ (1232) in the photon energy range 2.8 to 4.8 GeV. The total cross sections for ωΔ⁺ (1232) photo-production are found to be slightly larger than those for elastic ω photo-production in this energy range. The data are compared to the predictions of a theoretical model and the contributing exchange mechanics are discussed.     

X-ray photoelectron spectroscopy of nitroanilines and their derivatives

N 1s core-electron spectra have been studied for nitroanilines and related compounds. The spectral data are qualitatively interpreted by means of the molecules-in-molecule method, which describes the interaction between the aromatic amine part (donor moiety) and the nitro group (acceptor moiety) in terms of a composite system consisting of a donor and an acceptor. It was found that the nitro-N 1s spectra and the separation between the nitro-N 1s and the amino-N 1s ionization energies depend upon the magnitude of the intramolecular charge-transfer interaction in the ground state. A similarity between the relaxation effect in the nitro-N 1s or nitro-O 1s core-hole ion and a nitration reaction of the donor moiety is demonstrated.     

Assignment of the doublet states arising from ionization of chlorine lone-pairs in molecules possessing C2υ symmetry

The He(I) photoelectron spectra of Cl₂CCH₂, Cl₂CCF₂, Cl₂CF₂ and Cl₂CBr₂ have been recorded. Detailed assignments of the     

Lorentz force hydrophones at megahertz frequencies: theory,practice and applications

We extend prior electrodynamic transducer (EDT) designs to an underwater Lorentz force hydrophone constructed from thin-gauge wire that operates at megahertz frequencies (within an external magnetic field) and presents combined acoustic transparency and bidirectionality. Other advantages over conventional piezoelectric hydrophones include design versatility, easy fabrication, reproducible frequency characteristics, and apparently high fidelity signal reception. These features tend to offset the disadvantages of lower sensitivity and the requirement of an external magnetic field. Coupling between the incident acoustic wave and consequent motion of the wire is in principle independent of frequency and small wire diameter. Induced emf's may thus be used over a broad frequency range to measure acoustic fields or obtain reflection coefficient data for solids and liquids, such as that described below.     

A Raman spectroscopic study of the uranyl phosphate mineral threadgoldite

Raman spectra of threadgoldite at 298 and 77K are measured and interpreted for the first time. Bands related the (UO(2))(2+) and (PO(4))(3-) stretching and bending vibrations are tenatively attributed together with the bands assigned to the stretching a and bending vibrations of water molecules and hydroxyls. Hydrogen-bonding network and H(2)O and (OH)(-1) libration modes are mentioned. U-O bond lengths in uranyls are calculated via empirical relations R(U-O)=f[nu(1) and nu(3)(UO(2))(2+)]A. They are comparable to the values inferred from the single crystal structure analysis of threadgoldite.     

Iron nanoparticles in the coupling of alkyl halides with aryl Grignard reagents

Iron nanoparticles, either formed in situ stabilized by 1,6-bis(diphenylphosphino)hexane or polyethylene glycol (PEG), or preformed stabilized by PEG, are excellent catalysts for the cross-coupling of aryl Grignard reagents with primary and secondary alkyl halides bearing beta-hydrogens and they also prove effective in a tandem cyclization/cross-coupling reaction.     

Raman and infrared spectroscopy of the manganese arsenate mineral allactite

The mineral allactite [Mn(7)(AsO(4))(2)(OH)(8)] is a basic manganese arsenate which is highly pleochroic. The use of the 633 nm excitation line enables quality spectra of to be obtained irrespective of the crystal orientation. The mineral is characterised by a set of sharp bands in the 770-885 cm(-1) region. Intense and sharp Raman bands are observed at 883, 858, 834, 827, 808 and 779 cm(-1). Collecting the spectral data at 77K enabled better band separation with narrower bandwidths. The observation of multiple AsO(4) stretching bands indicates the non-equivalence of the arsenate anions in the allactite structure. In comparison the infrared spectrum shows a broad spectral profile with a series of difficult to define overlapping bands. The low wavenumber region sets of bands which are assigned to the nu(2) modes (361 and 359 cm(-1)), the nu(4) modes (471, 452 and 422 cm(-1)), AsO stretching vibrations at 331 and 324 cm(-1), and bands at 289 and 271 cm(-1) which may be ascribed to MnO stretching modes. The observation of multiple bands shows the loss of symmetry of the AsO(4) units and the non-equivalence of these units in the allactite structure. The study shows that highly pleochroic minerals can be studied by Raman spectroscopy.     

A Raman and infrared spectroscopic study of the uranyl silicates--weeksite, soddyite and haiweeite

Raman spectroscopy has been used to study the molecular structure of a series of selected uranyl silicate minerals, including weeksite K2[(UO2)2(Si5O13)].H2O, soddyite [(UO2)2SiO4.2H2O] and haiweeite Ca[(UO2)2(Si5O12(OH)2](H2O)3 with UO2(2+)/SiO2 molar ratio 2:1 or 2:5. Raman spectra clearly show well resolved bands in the 750-800 cm-1 region and in the 950-1000 cm-1 region assigned to the nu1 modes of the (UO2)2+ units and to the (SiO4)4- tetrahedra. For example, soddyite is characterized by Raman bands at 828.0, 808.6 and 801.8 cm-1 (UO2)2+ (nu1), 909.6 and 898.0 cm-1 (UO2)2+ (nu3), 268.2, 257.8 and 246.9 cm-1 are assigned to the nu2 (delta) (UO2)2+. Coincidences of the nu1 (UO2)2+ and the nu1 (SiO4)4- is expected. Bands at 1082.2, 1071.2, 1036.3, 995.1 and 966.3 cm-1 are attributed to the nu3 (SiO4)4-. Sets of Raman bands in the 200-300 cm-1 region are assigned to nu2 (delta) (UO2)2+ and UO ligand vibrations. Multiple bands indicate the non-equivalence of the UO bonds and the lifting of the degeneracy of nu2 (delta) (UO2)2+ vibrations. The (SiO4)4- tetrahedral are characterized by bands in the 470-550 cm-1 and in the 390-420 cm-1 region. These bands are attributed to the nu4 and nu2 (SiO4)4- bending modes. The minerals show characteristic OH stretching bands in the 2900-3500 cm-1 and 3600-3700 cm-1.