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971.
Berger C Fröhlich M Mönch H Nisius R Raupach F Schleper P Benadjal Y Blum D Bourdarios C Dudelzak B Eschstruth P Jullian S Lalanne D Laplanche F Longuemare C Paulot C Perdereau O Roy P Szklarz G Behr L Degrange B Minet Y Nguyen-Khac U Serri P Tisserant S Tripp RD Arpesella C Bareyre P Barloutaud R Borg A Chardin G Ernwein J Glicenstein JF Mosca L Moscoso L Becker J Becker KH Daum HJ Demski S Jacobi B Kuznik B Mayer R Meyer H Möller R Schubnell M Seyffert B Wei Y Wintgen P 《Physical review D: Particles and fields》1989,40(7):2163-2171
972.
Event rates and distributions for high mass gluinos and squarks are computed at Tevatron collider energies, imposing experimentally realisticP T cuts. Gluino and squark masses can be probed up to 200 GeV at \(\sqrt s = 2 TeV\) , and up to about 150 GeV at \(\sqrt s = 1.6 TeV\) with the supersymmetric signal being much more enhanced relative to the standard model background than at CERN \(\bar p\) energies. If the CERN UA1 missing-p T events are indeed indicative for the existence of gluinos and/or squarks with masses of about 50–70 GeV, then the Fermilab collider experiments should easily confirm the expected huge supersymmetric signals. 相似文献
973.
In this paper we present a comparative study of inelastic interactions of C12-Em and p-Em at 4·5 GeV/c per nucleon. The multiplicity distributions and their correlations have been studied. The results show a strong correlation of n
s onn
h in the case of C12-Em but not in the case of p-Em. It is also shown that the n
s increases with the increase of the projectile mass. The angular distribution of the target fragments in C12-Em shows a massive forward collimation. Comparison is also made in the pseudorapidity distribution of both C12-Em and p-Em, the result shows many interesting features. 相似文献
974.
Somnath Roy Tarak Nath Mandal Anil Kumar Barik Sachindranath Pal Samik Gupta Arijit Hazra Ray J. Butcher Allen D. Hunter Matthias Zeller Susanta Kumar Kar 《Polyhedron》2007
Two new pyrimidine based NNS tridentate Schiff base ligands S-methyl-3-((2-S-methyl-6-methyl-4-pyrimidyl)methyl)dithiocarbazate [HL1] and S-benzyl-3-((2-S-methyl-6-methyl-4-pyrimidyl)methyl)dithiocarbazate [HL2] have been synthesised by the 1:1 condensation of 2-S-methylmercapto-6-methylpyrimidine-4-carbaldehyde and S-methyl/S-benzyl dithiocarbazate. A Ni(II) complex of HL1 and Co(III) and Fe(III) complexes of HL2 have been prepared and characterized by elemental analyses, molar conductivities, magnetic susceptibilities and spectroscopic studies. All the bis-chelate complexes have a distorted octahedral arrangement with an N4S2 chromophore around the central metal ion. Each ligand molecule binds the metal ion using the pyrimidyl and azomethine nitrogen and thiolato sulfur atoms (except in the nickel complex, one ligand molecule uses the thione sulfur in lieu of thiolato sulfur atom). In the Ni(II) complex, one of the ligand molecules behaves as a neutral tridentate and the other molecule functions as a uninegative tridentate, whereas in the Co(III) and Fe(III) complexes, the ligand molecules behave as monoanionic tridentate. All the complexes were analyzed by single crystal X-ray diffraction and significant differences concerning the distortion from an octahedral geometry of the coordination environment were observed. 相似文献
975.
Atomic-absorption methods for determination of antimony at mug/g levels in rocks and sulphide ores by flame atomization (FAA) and electrothermal atomization (ETAA) have been described. The FAA method involves the separation of antimony from matrix elements by extraction as the iodide into methyl isobutyl ketone containing tri-n-octylphosphine oxide, from dilute hydrochloric acid solution, followed by direct aspiration of the extract into an air-acetylene flame. If necessary, antimony is first separated from copper and lead by co-precipitation with hydrous ferric oxide from ammoniacal medium and by precipitation of lead as lead sulphate. The ETAA method involves co-precipitation of antimony with hydrous ferric oxide followed by dissolution of the precipitate in dilute nitric acid, mixing with nickel solution as releasing agent, and ETAA measurement by use of a tungsten strip atomizer. 相似文献
976.
Optimization of single-column anion chromatography with indirect photometric and indirect fluorimetric detection is described. A simplex algorithm is used for signal maximization with eluent concentration, pH and flow rates as dependent variables. Absolute detection limits obtained for chloride, nitrite, nitrate and sulphate by indirect photometric detection were 1.0, 1.2, 1.4, and 2.0 ng, respectively. The use of single-beam indirect fluorimetric detection of these anions is also demonstrated. The method was applied to the detection of anions arising from gaseous acids or atmospheric aerosols. 相似文献
977.
Peter Cooper Roy Fields Robert N. Haszeldine Gordon H. Mitchell Shmaiel N. Nona 《Journal of fluorine chemistry》1982,21(3):317-327
Tris(trifluoromethyl)phosphine and ethylene reacted efficiently under u.v. irradiation to give 3,3,3-trifluoropropylbis(trifuomothyl) phosphine in good yield. With vinyl fluoride, vinylidene fluoride, and propene the reaction was regioselective rather than regiospecific, and the yield of 1:1 adduct was low. In these reactions, and in those with vinyl chloride, but-1-ene, and hexafluoropropene, in which only traces of 1:1-adduct could be detected, the bulk of the olefin and of the phosphine was recovered, and numerous by-products consistent with radical intermediates were identified. With propyne, 1,1,1-trifluoro-3-bis(trifluoromethyl)phosphino-cis-but-2-ene was obtained in moderate yield, but no reaction occurred between the phosphine and either but-2-yne or hexafluorcbut-2-yne. Tris(trifluoromethyl)phosphine oxide did not form an adduct with ethylene, tetrafluoroethylene, or propyne.Bis(trifluoromethyl)phosphine and dimethylphosphine both reacted readily under u.v. irradiation with 3,3,3-trifluoropropene, the phosphinyl radical attacking the terminal carbon in each case. 相似文献
978.
Raymond A. Poirier Raymond Daudel Roy E. Kari Imre G. Csizmadia 《International journal of quantum chemistry》1984,25(2):411-421
Closed-shell RHF one-electron properties are calculated for H2S using a total of 41 different s, p basis sets and two polarized basis sets (6–31G* and 6–31G**). Total energies and geometries alone are not a comprehensive criteria for selecting the best basis sets. It is shown here that the comparison of a number of one-electron properties can serve as an excellent criteria for testing basis sets. The quality or reliability of a basis set is taken as being its agreement with a large uncontracted s, p basis set (s, p limit). 相似文献
979.
Factors influencing the transport of short-chain alcohols through mesoporous gamma-alumina membranes
The pressure-driven transport of water, ethanol, and 1-propanol through supported gamma-alumina membranes with different pore diameters is reported. Water and alcohols had similar permeabilities when they were transported through gamma-alumina membranes with average pore diameters of 4.4 and 6.0 nm, and the permeability coefficient was found to be proportional to the square of pore size, in accordance with a viscous flow mechanism. For transport through membranes with an average diameter of 3.2 nm, the behavior of water was in accordance with the viscous flow mechanism, but the permeability of the membrane for ethanol and 1-propanol was much smaller than expected and could not be explained in terms of viscous flow. Although the low permeability of the membrane with 3.2 nm pores for ethanol and 1-propanol was partly due to the presence of small amounts of water in the alcohols, the permeability coefficients were still substantially smaller when water was absent. This intrinsic difference between water and alcohol may be due to differences in molecular size, chemisorption of alcohols on the oxide pore wall, which would lead to a reduction of the effective pore size, and/or a certain degree of translational ordering of the alcohol molecules inside the membrane pores, which leads to an effectively higher viscosity and, therefore, to a higher transport resistance. 相似文献
980.
Effective sorbents for solid-phase extraction in the analysis of quinolones in animal tissues by capillary electrophoresis 总被引:1,自引:0,他引:1
In this work, several commercial sorbents (Zorbax C18, Bond Elut C18, Isolute ENV+, Oasis HLB, Oasis MAX, SDB-RPS, and MPC-SD) were compared for the solid-phase extraction of the series of quinolones regulated by the European Community in chicken tissues in order to establish a method for the determination of this series of quinolones by capillary electrophoresis and diode array detection. Sorbents were chosen in order to achieve maximum recoveries and optimal clean-up efficiency. Better results were obtained using SDB-RPS and Oasis MAX which would provide suitable limits of detection, below of the maximum residue limits (MRLs) regulated. 相似文献