Development of phase composition for mixed Ni?Cu chromite catalysts. Conversions under calcination

IR spectroscopic and X-ray studies of variations in the composition of Ni, Cu and (Ni+Cu) ammonium chromates under thermal treatment show that the Ni–Cr system consists of spinel and NiO, and Cu–Cr systems consist of the spinel CuCr₂O₄ only. In mixed Ni–Cu–Cr systems part of Ni- and Cu-containing components remain independent and part of them form common Ni+Cu phases.

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Ni-, Cu- (Ni+Cu)- . , Ni–Cr NiO, Cu–Cr — CuCr₂O₄. Ni–Cu–Cr Ni- Cu- , Ni+Cu .

     

Kinetics and Phase Transformations during the Decomposition of Supersaturated Solid Solutions of Magnesium in Mg–Dy–Sm Alloys

Kinetics and phase transformations are studied for the previously unconsidered decomposition of supersaturated solid solution in magnesium-based alloys Mg–Dy–Sm. The decomposition of solid solution slows when there is an increase in % Dy: % Sm ratio in the alloys. Mg–Sm and Mg–Dy alloys grow harder when Dy and Sm are added to them, respectively. Products of decomposition in ternary Mg–Dy–Sm alloys are the same as in binary alloys Mg–Dy and Mg–Sm but contain combinations of Dy and Sm.     

Hadrons and other secondaries generated by cosmic-ray muons underground

Summary The production of nuclear-active and electromagnetic particles, as well as long-lived isotopes in nuclear and electromagnetic showers generated by cosmic-ray muons at different depths underground is discussed. Characteristics of the secondary components and their dependence on the depth and the muon energy, obtained in experiments and calculations, are presented.     

Upper limit on the solar antineutrino flux according to LSD data

The experimental data obtained on the liquid scintillation detector LSD are analyzed for the purpose of searching for the solar electron antineutrino flux predicted in the model of spin-flavor precession of the neutrino. The currently most accurate upper limit on the solar v̄_e/v _e flux ratio is established: Φ_v̄/Φ_v⩽1.7% (90% confidence range). Pis’ma Zh. éksp. Teor. Fiz. 63, No. 10, 753–757 (25 May 1996) The spelling of the authors names are presented here in English as requested by the Russian Editorial office.     

Direct experimental test of non-separability and other quantum techniques using continuous variables of light

We present schemes for the generation and evaluation of continuous variable entanglement of bright optical beams and give a brief overview of a variety of optical techniques and quantum communication applications on this basis. A new entanglement-based quantum interferometry scheme with bright beams is suggested. The performance of the presented schemes is independent of the relative interference phase which is advantageous for quantum communication applications. Received 1st August 2001     

Development of phase composition for mixed Ni?Cu chromite catalysts. Interaction of initial substances

IR spectroscopic and kinetic studies of the interaction between basic carbonates of Cu and Ni and H₂CrO₄ allows to suppose that catalyst formation is affected by different structures of the initial substances. The formation of mixed Ni–Cu–Cr phases is observed during the step of chromate formation and is preserved after treatment by ammonium.

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Cu Ni H₂CrO₄. , . Ni–Cu–Cr- .

     

Squeezed light from microstructured fibres: towards free-space quantum cryptography

Amplitude-squeezed pulsed light has been produced using a microstructured silica fibre. By spectrally filtering after the non-linear propagation in the fibre a squeezing value of -1.7 dB has been measured. A quantum key distribution scheme based on squeezed light from such microstructured fibres is proposed. Received: 9 July 2001 / Published online: 23 November 2001     

A simple procedure for estimating changes in the nuclear configuration of molecules in the excited ππ*-electronic state

A simple procedure is suggested for estimating changes in the bond lengths q and angles a between them in the excited ππ states of molecules avoiding calculations of molecular vibrations. The distances q and the angles a are estimated for the triplet state B_1u (ππ*) of the tetm-β-chlomdioxin molecule. Translated from Zhumal Struktumoi Khimii, Vol. 41, No. 1, pp. 149-156, January–February, 2000.