О формуле объема гиперболического четырехмерного симплекса

In this paper, we derive an explicit formula for the volume of abritrary hyperbolic 4-simplex depending on vertices coordinates.В настоящей работе получена явная формула объема произвольного гиперболического 4-симплекса через координаты вершин

О применении современного доказательства формулы Сфорца к вычислению объемов гиперболических тетраэдров специального вида

In this paper, we use the contemporary proof (by Abrosimov and Mednykh) of the Sforza formula for volume of an arbitrary non-Euclidean tetrahedron to derive new formulas that express volumes of hyperbolic tetrahedra of special kind (orthoschemes and tetrahedra with the symmetry group S 4) via dihedral angles.В настоящей работе мы, используя современное доказательство формулы Сфорца объема произвольного неевклидова тетраэдра, предложенное Н.В. Абросимовым и А.Д. Медных, выведем новые формулы, выражающие объемы гиперболических тетраэдров специального вида (ортосхемы и тетраэдры с группой симметрии S 4) через двугранные углы

Planar SFS Josephson Junctions Made by Focused Ion Beam Etching

Superconductor-Ferromagnet-Superconductor (S-F-S) Josephson junctions were fabricated by making a narrow cut through a S-F double layer using direct writing by Focused Ion Beam (FIB). Due to a high resolution (spot size smaller than 10 nm) of FIB, junctions with a small separation between superconducting electrodes ($\leq$ 30 nm) can be made. Such a short distance is sufficient for achieving a considerable proximity coupling through a diluted CuNi ferromagnet. We have successfully fabricated and studied S-F-S (Nb-CuNi-Nb) and S-S'-S (Nb-Nb/CuNi-Nb) junctions. Junctions exhibit clear Fraunhofer modulation of the critical current as a function of magnetic field, indicating good uniformity of the cut. By changing the depth of the cut, junctions with the $I_c R_n$ product ranging from 0.5 mV to $\sim 1\mu$V were fabricated.Comment: 5 pages, 5 figures, presentation at EUCAS-2003, to be published in Physica

Diode temperature sensors with tunable sensitivity

We investigated the possibility of using of AlGaInP heterostructures with p-n junction as diode temperature sensors having quasi-linear dependence of the forward voltage drop on the ambient temperature at the fixed direct current. Thus we measured the current-voltage characteristics of the p-n structures in the temperature range 293-550 K. Using the data obtained we calculated the differential current thermal sensitivity of the structures mentioned. A semilogarithmic plot of the thermal sensitivity vs. forward current dependence is presented in the figure

Minimal operation current estimation for the temperature sensors based on p+-n GaP diode structures

A decrease of the operation current of diode temperature sensors (DTS) allows to considerably reduce the systematic measurement error of the sensors. In this connection we have made an estimation of the minimum operation current magnitude for p+-n GaP DTS. Thus there is an operation current I at which the total systematic error is minimal. This value I = Imin is taken as the desired current value

Minimal operation current estimation for the temperature sensors based on p+-n GaP diode structures

A decrease of the operation current of diode temperature sensors (DTS) allows to considerably reduce the systematic measurement error of the sensors. In this connection we have made an estimation of the minimum operation current magnitude for p+-n GaP DTS. Thus there is an operation current I at which the total systematic error is minimal. This value I = Imin is taken as the desired current value

Synthesis, characterisation and corrosion behaviour of simulant Chernobyl nuclear meltdown materials

Understanding the physical and chemical properties of materials arising from nuclear meltdowns, such as the Chernobyl and Fukushima accidents, is critical to supporting decommissioning operations and reducing the hazard to personnel and the environment surrounding the stricken reactors. Relatively few samples of meltdown materials are available for study, and their analysis is made challenging due to the radiation hazard associated with handling them. In this study, small-scale batches of low radioactivity (i.e., containing depleted uranium only) simulants for Chernobyl lava-like fuel-containing materials (LFCMs) have been prepared, and were found to closely approximate the microstructure and mineralogy of real LFCM. The addition of excess of ZrO2 to the composition resulted in the first successful synthesis of high uranium–zircon (chernobylite) by crystallisation from a glass melt. Use of these simulant materials allowed further analysis of the thermal characteristics of LFCM and the corrosion kinetics, giving results that are in good agreement with the limited available literature on real samples. It should, therefore, be possible to use these new simulant materials to support decommissioning operations of nuclear reactors post-accident

Measurement of the vector and tensor analyzing powers for dp- elastic scattering at 880 MeV

The vector Ay and tensor analyzing powers Ayy and Axx for dp- elastic scattering were measured at Td = 880 MeV over the c.m. angular range from 60 to 140 degrees at the JINR Nuclotron. The data are compared with predictions of different theoretical models based on the use of nucleon-nucleon forces only. The observed discrepancies of the measured analyzing powers from the calculations require the consideration of additional mechanisms.Comment: 5 pages,3 figure