Elliptic flow of charged particles in Pb-Pb collisions at sqrt[S(NN)] = 2.76 TeV

We report the first measurement of charged particle elliptic flow in Pb-Pb collisions at sqrt[S(NN)] =2.76 TeV with the ALICE detector at the CERN Large Hadron Collider. The measurement is performed in the central pseudorapidity region (|η|<0.8) and transverse momentum range 0.2

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Methods of analytical mechanics in the constrained adaptive identification problems

The application of analytical mechanics methods to the problem of adaptive identification is discussed. The estimated constant parameters satisfy nonlinear equations considered as parametric constraints. Some modifications of identification algorithms are proposed to satisfy such constraints.     

Damping characteristics of a reentry vehicle at hypersonic velocities

The experimental equipment, model, test conditions, and methods used for determining the streamwise damping on a setup with free oscillations on rolling bearings are described. Characteristics of aerodynamic damping of the model with two positions of the rotation axis and Mach numbers M_∞ = 2, 4, and 6 are measured. Irregular oscillations of the model with a greater displacement of the rotation axis with respect to the longitudinal axis are found to arise at M_∞ = 2.     

Separation selectivity of some ethylenediaminetetraacetic acid and cyclohexane-1,2-diaminetetraacetic acid complexes in column and ion electrokinetic chromatography

The complexes of Mn²⁺, Cd²⁺, Fe³⁺, Pb²⁺, Ni²⁺, Co²⁺, Zn²⁺ and Cu²⁺ with EDTA and cyclohexane-1,2-diaminetetraacetic acid (CDTA) were separated and detected in column and ion electrokinetic chromatography with suppressed conductivity and direct UV detection, respectively. In column ion chromatography (IC) these complexes were separated on an IonPac AS4A anion-exchange column (Dionex, USA). Parameters of carrier electrolyte, which were examined in the ion electrokinetic chromatography (IEKC) mode, include polymer and sulfate concentrations. In IEKC separation selectivity of complexes with poly(diallyldimethylammonium) cation as modifier is similar as for an IonPac AS4A column both for EDTA and CDTA chelates. It was shown that the ion-exchange capacity of the electrokinetic system is more than 100-times lower than the capacity of the IC column for the same peak resolution. In comparison with column main advantages of electrokinetic version are high separation efficiency (220 000–390 000 theoretical plates) and the absence of the analyte interaction with the sorbent matrix.     

2-Chloroisobutylmonohydrotrifluorophosphorane

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, p. 494, February, 1988.     

Purification of krypton-xenon mixture from fluorine-containing gases

Active alumina was used to purify krypton-xenon mixtures from fluorine-containing gases (tetrafluoromethane and sulfur hexafluoride). At 580°C, the admixtures are converted into aluminum trifluoride, with their content in the test gas mixture reducing from hundreds of ppm to 0.1 ppm or even below.     

Separation of different ion structures in atmospheric pressure photoionization-ion mobility spectrometry-mass spectrometry (APPI-IMS-MS)

This study demonstrates how positive ion atmospheric pressure photoionization-ion mobility spectrometry-mass spectrometry (APPI-IMS-MS) can be used to produce different ionic forms of an analy te and how these can be separated. When hexane:toluene (9:1) is used as a solvent, 2,6-di-tert-butylpyridine (2,6-DtBPyr) and 2,6-di-tert-4-methylpyridine (2,6-DtB-4-MPyr) efficiently produce radical cations [M]⁺ and protonated [M + H]⁺ molecules, whereas, when the sample solvent is hexane, protonated molecules are mainly formed. Interestingly, radical cations drift slower in the drift tube than the protonated molecules. It was observed that an oxygen adduct ion, [M + O₂]⁺, which was clearly seen in the mass spectra for hexane:toluene (9:1) solutions, shares the same mobility with radical cations, [M]⁺. Therefore, the observed mobility order is most likely explained by oxygen adduct formation, i.e., the radical cation forrning a heavier adduct. For pyridine and 2-tert-butylpyridine, only protonated molecules could be efficiently formed in the conditions used. For 1- and 2-naphthol it was observed that in hexane the protonated molecule typically had a higher intensity than the radical cation, whereas in hexane:toluene (9:1) the radical cation [M]⁺ typically had a higher intensity than the protonated molecule [M + H]⁺. Interestingly, the latter drifts slower than the radical cation [M]⁺, which is the opposite of the drift pattern seen for 2,6-DtBPyr and 2,6-DtB-4-MPyr.     

Doppler spectroscopy of hydrogen and deuterium Balmer alpha line in an abnormal glow discharge

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