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121.
I. V. Ajinenko P. V. Chliapnikov V. P. Falaleev Z. C. Garutchava L. N. Gerdyukov V. V. Kniazev A. I. Kurnosenko T. G. Makharadze V. N. Riadovikov A. M. Rybin A. G. Tomaradze O. G. Tchikilev V. F. Tchunikhin V. A. Uvarov A. P. Vorobjev N. S. Amaglobely Ch. S. Chochiachvili M. D. Tabidze M. Barth E. A. De Wolf M. Van Immerseel F. Verbeure CERN-USSR Collaboration 《Zeitschrift fur Physik C Particles and Fields》1984,23(4):307-331
The production properties ofK s 0 , \(\bar \Lambda\) andK + p interactions at 32 GeV/c are investigated using the final statistics of the experiment. We present total and semi-inclusive cross sections and aver-age multiplicities. Estimates are given of the diffractive dissociation contributions to total and differential cross sections. Thex-,p T ?, and transverse mass dependence of inclusive and semi-inclusive distributions is discussed as well as properties of “prompt”K s 0 's. The ratio of “prompt”K 890 + (K 890 0 ) to “prompt”K 0 cross sections is measured to be 1.03±0.12 (0.98±0.17). From a comparison of \(\bar \Lambda\) production inK ± p interactions at 32 GeV/c, we estimate a strange sea-quark suppression of 0.26 ±0.02. The double differential cross sections ofK s 0 's is studied as a function of Feynman-x andp T 2 , and a Triple-Regge fit performed. The data are compared in detail to versions of the Lund-model for low-p T hadronic collisions. 相似文献
122.
H. Huber Ch. Koeberl I. McDonald W.U. Reimold 《Journal of Radioanalytical and Nuclear Chemistry》2000,244(3):603-607
We used - coincidence spectrometry to investigate the possible presence of a meteoritical component in 27 samples of South African diamictites. Recently, several studies have suggested that some tillites/diamictites may represent impact breccias, but a petrographical study by our group found no evidence for the presence of impact-characteristic shocked minerals. The siderophile elements, such as Cr, Co, Ni, and, especially, the platinum group elements, have high abundances in meteorites, but low abundances in terrestrial crustal rocks. The Ir content of the diamictites was measured with the new iridium coincidence spectrometer (ICS) at the University of Vienna, with detection limits of around 0.02 ppb. No enrichments in the contents of Ir and other siderophile elements compared to average crustal concentrations were found; thus, no unequivocal evidence for an impact origin of these diamictites of the South African Dwyka Group can be documented. 相似文献
123.
Ch. Linga Raju K.V. Narasimhulu N.O. Gopal J.L. Rao B.C.V. Reddy 《Journal of Molecular Structure》2005,754(1-3):100-105
Electron paramagnetic resonance (EPR) studies have been carried out on VO2+ ions doped in single crystals of ferroelectric material, potassium thiourea bromide (PTB) at room temperature and in the temperature range 103–343 K on X-band MW frequency. An isotropic octet spectrum characteristic of VO2+ ion was obtained due to the fast re-orientation of the VO2+ in PTB lattice, which exhibits glassy nature at certain range around room temperature. The temperature dependant EPR spectra of VO2+ ions in this host lattice has been attributed to the occurrence of multiple phase transitions due to the combined environment effects of KBr and thiourea materials in the single crystal. From the optical absorption spectrum, the crystal field splitting parameter Dq, tetragonal parameters Ds and Dt have been evaluated and discussed. 相似文献
124.
L.V. Vinogradova N.I. Nikolaev V.N. Sgonnik B.L. Erussalimsky G.V. Sinitsina Ch.B. Tsvetanov I.M. Panayotov 《European Polymer Journal》1981,17(5):517-520
The parallel changes in the electric conductivity and u.v. spectra of polybutadienyl- and polyisoprenyl-lithium (MnLi) have been investigated in tetrahydrofuran and dimethoxyethane solutions during prolonged storage at 0 and 25°. A considerable dependence of the rate of these changes on the nature of the medium and Mn Li concentration was found. The decrease in the initiating activity during storage has been estimated for the PBLi-THF system. 相似文献
125.
Historical aspects of science are usually confined to special conferences, and receive only a brief mention in the introduction to talks at meetings addressing current topics. However, at the previous Seminar, several theoretical and experimental contributions were made, which discussed the historical development of surface science. Because of the considerable interest aroused by these presentations, we decided to keep the historical spirit alive, by telling the story of photoemission.
While field emission is the oldest area of surface science, photoemission is certainly one of the most important branches. Here, emphasis is placed on the early investigations, which are often scarcely mentioned, and on more recent work that has had significant impact on the progress of surface science. 相似文献
126.
Ch. S. Becker G. I. Roshchupkina T. V. Rybalova Yu. V. Gatilov V. A. Reznikov 《Russian Chemical Bulletin》2007,56(6):1210-1215
In some cases, the reactions of enaminones of the imidazolidine 1-oxide series with the Vilsmeier reagent afford electrophilic
substitution products containing the dimethyl-aminomethylene group. In an acidic medium, these products undergo either hydrolytic
elimination of the dimethylaminomethylene moiety or hydrolysis of the latter to form the aldehyde group. The reaction of nitroenamine,
which is a derivative of imidazolidine 1-oxide, with the Vilsmeier reagent produces furoxane, viz., the nitroxyl biradical. Reduction of the latter affords the dioxime biradical.
Dedicated to the memory of Academician N. N. Vorozhtsov on the 100th anniversary of his birth.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1165–1170, June, 2007. 相似文献
127.
Ch. Berthelot G. Carraro V. Verdingh 《Journal of Radioanalytical and Nuclear Chemistry》1980,60(2):443-451
A large number of toxic elements, including Th and U, in Scheldt and NBS river sediments, have been determined non-destructively
by high energy photon activation. The length of irradiation varies between 1.5 hours for short lived-nuclides and 7–18 hours
for long lived-nuclides. The induced activities are measured using a single open-ended coaxial Ge(Li) detector and the photopeak
integrations are calculated using the total peak area method and the Cutipie computer program after substraction of the intrinsic
background of the detector from each spectrum (Angela program). The photonuclear reactions and the best detection limits for
36 elements are indicated. 相似文献
128.
K. Ardhaoui J. Rogez A. Ben Chérifa M. Jemal P. Satre 《Journal of Thermal Analysis and Calorimetry》2006,86(2):553-559
Lanthanum-bearing silicate-oxyapatites or britholites, Ca10–xLax(PO4)6–x(SiO4)xO with 1≤x≤6, have been synthesized by solid state reaction
at high temperature. They were characterized by X-ray diffraction and IR spectroscopy.
Using two microcalorimeters, the heat of solution of these compounds have
been measured at 298 K in a solution of nitric and hydrofluoric acid. A strained
least squares method was applied to the experimental results to obtain the
solution enthalpies at infinite dilution, and the mixing enthalpy in two steps.
In the first step the mixing enthalpy obtained is referenced to the britholite
monosubstituted and to the oxysilicate. The mixing enthalpy referenced to
the oxyapatite and to the oxysilicate is then extrapolated. In order to determine
the enthalpies of formation of all the terms of the solution, thermochemical
cycles were proposed and complementary experiments were performed. The results
obtained show a decrease of the enthalpy of formation with the amount of Si
and La introduced in the lattice. This was explained by the difference in
the bond energies of (Ca–O, P–O) and (La–O, Si–O). 相似文献
129.
Doz. Dr. Herfried Griengl Klaus Peter Geppert 《Monatshefte für Chemie / Chemical Monthly》1976,107(3):675-684
By 1,4-addition of arylaldehydes to 2,3-dimethyl-1,3-butadiene in the presence of sulfuric acid 2-aryl-4,5-dimethyl-3,6-dihydro-2H-pyrans are obtained. From 1,3-butadiene and isoprene beside the corresponding 3,6-dihydro-2H-pyrans by reaction with two more molecules aldehydetrans-2,4,7-triphenyl-4a,7,8,8a-tetrahydro-4H,5H-pyrano[4,3-d-1,3-dioxines are formed. With 1,3-cyclohexadiene, however, 1,2-addition of benzaldehyde is observed to givecis-r-2,c-4-diphenyl-4a,5,6,8a-tetrahydro-1,3-benzodioxane.
Herrn Prof. Dr.Anton v. Wacek, emerit. Vorstand des Instituts für Organische Chemie und Organisch-chemische Technologie der Technischen Universität Graz, in Verbundenheit zum 80. Geburtstag gewidmet.
1. Mitt.:H. Griengl undK. P. Geppert, Mh. Chem.107, 421 (1976). 相似文献
Herrn Prof. Dr.Anton v. Wacek, emerit. Vorstand des Instituts für Organische Chemie und Organisch-chemische Technologie der Technischen Universität Graz, in Verbundenheit zum 80. Geburtstag gewidmet.
1. Mitt.:H. Griengl undK. P. Geppert, Mh. Chem.107, 421 (1976). 相似文献
130.
J. Kvasil I. N. Mikhailov R. Ch. Safarov B. Choriev 《Czechoslovak Journal of Physics》1978,28(8):843-856
Some generalizations of the model for odd nuclei suggested by Kerman are considered. The effects of phonon admixtures on matrix elements of Coriolis interaction are studied. Several schemes are considered for studying the role of non-adiabatic effects in the even-even core.One of the authors B. Ch. thanks L. A.Malov and V. O.Nesterenko for many discussions of some questions connected with the determination of the phonon-quasiparticle admixtures. 相似文献