197Au Mössbauer study of a gold-doped YBa2Cu3O7-σ high-temperature superconductor

A high temperature superconductor with the composition YBa₂Cu_2.9Au_0.1O_7– was studied by Mössbauer spectroscopy with the 77 keV gamma rays of¹⁹⁷Au, by X-ray diffraction, and by magnetization measurements. The main component in the Mössbauer spectrum, a quadrupole doublet with an isomer shift of +3.29 mm/s with respect to metallic gold and a quadrupole splitting of 3.61 mm/s, can be attributed to Au³⁺ in a square planar oxygen coordination, as is expected for gold replacing Cu(1). A further, weak doublet becomes dominant upon reduction of the specimen, and has an isomer shift of +3.46 mm/s and a quadrupole splitting of 7.12 mm/s. This component may be Au⁺ or Au³⁺ in an unusual coordination. Only a small fraction of the gold was found to be metallic in both the oxidized and the reduced state.     

Capillary isoelectric focusing with UV-induced fluorescence detection

Low-molecular-mass fluorescent compounds excitable in the near UV region with suitable acidobasic and electrophoretic properties are suggested as isoelectric point (pI) markers for isoelectric focusing (IEF) with UV photometric and UV excited fluorometric detection. The experimental set-up of capillary IEF with UV excited fluorometric detection and properties of new UV-induced fluorescent pI markers are given. The pI values of 18 new pI markers determined independently of IEF methods range from 2.1 to 10.3. The examples of separation of new pI markers together with derivatized proteins by capillary IEF with photometric or fluorometric detection are presented.     

Relationship between Electronic Charges at Nitrogen Atoms of Nitro Groups and Thermal Reactivity of Nitramines

Thermal reactivity of eleven nitramines has been examined by means of non-isothermal differential thermal analysis, and the data were analyzed according to the Kissinger method. The reactivity was expressed as the E _a R ⁻¹ slopes of the Kissinger relationship. Electronic charges, q ^N, at nitrogen atoms of the nitramine molecules were calculated by means of ab initio DFT B3LYP/6-31G** method. The relationships were confirmed between the slopes E _a R ⁻¹ and the q values for the nitro groups that are primarily split off. Conclusions are made in relation to the mechanism of initiation of polynitro compounds in general. This revised version was published online in July 2006 with corrections to the Cover Date.     

Übero-p-Dinitrobenzaldehyd

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Die Viskosimetrie des lebenden Protoplasmas

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Search for the standard model Higgs boson in the decay channel H→ZZ→4ℓ in pp collisions at √s=7 TeV

A search for a Higgs boson in the four-lepton decay channel H→ZZ, with each Z boson decaying to an electron or muon pair, is reported. The search covers Higgs boson mass hypotheses in the range of 110100 GeV (with 13 below 160 GeV), while 67.1±6.0 (9.5±1.3) events are expected from background. The four-lepton mass distribution is consistent with the expectation of standard model background production of ZZ pairs. Upper limits at 95% confidence level exclude the standard model Higgs boson in the ranges of 134-158 GeV, 180-305 GeV, and 340-465 GeV. Small excesses of events are observed around masses of 119, 126, and 320 GeV, making the observed limits weaker than expected in the absence of a signal.     

Search for signatures of extra dimensions in the diphoton mass spectrum at the large hadron collider

A search for signatures of extra spatial dimensions in the diphoton invariant-mass spectrum has been performed with the CMS detector at the LHC. No excess of events above the standard model expectation is observed using a data sample collected in proton-proton collisions at √s=7 TeV corresponding to an integrated luminosity of 2.2 fb(-1). In the context of the large-extra-dimensions model, lower limits are set on the effective Planck scale in the range of 2.3-3.8 TeV at the 95% confidence level. These limits are the most restrictive bounds on virtual-graviton exchange to date. The most restrictive lower limits to date are also set on the mass of the first graviton excitation in the Randall-Sundrum model in the range of 0.86-1.84 TeV, for values of the associated coupling parameter between 0.01 and 0.10.