Signature Inversion as a Probe for Triaxial Rotation

The signature inversion phenomenon has been widely observed in nuclear rotational spectra but has no common understanding for more that 20 years. The triaxial rotation is a fundamental question in nuclear structure. The present study attempts to achieve a…     

γ-Spectrometric determination of the content of natural radionuclides in natural waters

Our investigations have shown that γ-spectrometry can be used to determine with acceptable accuracy the natural radionuclide content of natural waters, starting with specific activity 1.5 Bq/kg of the radionuclides in the samples. The accuracy of the determination of the activity can be increased by using an inert sample, which is certified with respect to the natural content of radionuclides, and better detectors. The natural content of radionuclides in the experimental samples of natural waters of Uzbekistan does not exceed the maximum admissable concentration. 3 figures, 1 table, 4 references. Translated from Atomnaya énergiya, Vol. 86, No. 1, pp. 36–40, January, 1990.     

Signature Inversion as a Probe for Triaxial Rotation

HI-13串列加速器升级工程是国家的一项重要建设工程。2005年是串列升级工程初步设计工作的关键一年，初步设计工作基本完成，初步设计评审准备工作和开工前的准备工作也同期展开。     

Axisymmetric Mirror as a Driver for a Fusion–Fission Hybrid: Physics Issues

The axisymmetric mirror has a number of attractive features as a driver for a fusion-fission hybrid system: geometrical simplicity, inherently steady-state operation, and the presence of natural divertors in the form of end tanks. Operation at Q ~ 1 allows for relatively low electron temperatures, in the range of 4 keV, for the DT injection energy ~80 keV. A simple mirror with the plasma diameter of 1 m and mirror-to-mirror length of 35 m is discussed. A brief qualitative discussion of three groups of physics issues is presented: axial heat loss, MHD stability in the axisymmetric geometry, and the microstability of sloshing ions.     

γ-X-ray-spectrometric investigation of plutonium and241Am content in the soil in regions where peaceful nuclear explosions were conducted

A brief exposition of the γ-x-ray spectrometric method and apparatus for analyzing the content of plutonium and²⁴¹Am in samples of soil and vegetation is presented. The results of an analysis of some samples from the regions where peaceful nuclear explosions were conducted in Yakutiya and Perm oblast' are presented. It is concluded that the γ-x-ray spectrometric method can be used to perform large-scale measurements in regions where peaceful nuclear explosions have been conducted, 2 figures, 3 tables, 8 references. Translated from Atomnaya énergiya, Vol. 88, No. 1, pp. 52–55, January, 2000.     

Dilepton as a signature for baryon—rich quark—gluon matter

Considered the Drell-Yan background in the intermediate invariant mass region,the dilepton production in an expanding hot baryon-rich quark-gluon matter fire-cylinder has been studied based on a previonsly established relativistic hydrodynamic model.It is found that with incresing the rapidity the dilepton yield is strongly suppressed.Such a characteristic,signaling the formation of the baryon-rich quark-gluon matter,can be tested in future experiments at Brookhaven and CERN.     

Effects of the electric field at the edge of a substrate to deposit a Ø100 mm uniform diamond film in a 2.45 GHz MPCVD system

In this study, uniform diamond films with a diameter of 100 mm were deposited in a 15 kW/2.45 GHz ellipsoidal microwave plasma chemical vapour deposition system. A phenomenological model previously developed by our group was used to simulate the distribution of the electric strength and electron density of plasma. Results indicate that the electric field in the cavity includes multiple modes, i.e. TM02 and TM03. When the gas pressure exceeds 10 kPa, the electron density of plasma increases and plasma volume decreases. A T-shaped substrate was developed to achieve uniform temperature, and the substrate was suspended in air from Ø70 to 100 mm, thus eliminating vertical heat dissipation. An edge electric field was added to the system after the introduction of the T-shaped substrate. Moreover, the plasma volume in this case was greater than that in the central electric field but smaller than that in the periphery electric field of the TM02 mode. This indicates that the electric field above and below the edge benefits the plasma volume rather than the periphery electric field of the TM02 mode. The quality, uniformity and surface morphology of the deposited diamond films were primarily investigated to maintain substrate temperature uniformity. When employing the improved substrate, the thickness unevenness of the Ø100 mm diamond film decreased from 22% to 7%.     

Establishment of a Radioimmunoassay for Anti-thyroid Peroxidase Antibodies in Human Serum

Quantitative assay for circulating TPOAb is the most sensitive test for autoimmune thyroid diseases.It is also used in assessing long-term risk of thyroid dysfunction in postmenopausal women and plays animportant role in managing pregnancy and postpartum thyroiditis. A quantitative radioimmunoassay for anti-thyroid peroxidase antibodies(TPOAb) in human serum     

Development of a Immunoradiometric Assay for Quantifying NSE in Human Serum

Neuron-specific enolase(NSE) is a tumor marker for neuroblastoma and also one of the mostsensitive and specific marker for small-cell lung cancer(SCLC) which has neuroendocrine properties withover-expressing of NSE. Quantitative assay for circulating NSE has clinic significance in monitoring oftherapy and prognosis for the cancer.     

Monitoring ofγ-radiation on flat landscapes in the rapid-search mode for above-background spots

Institute of General and Nuclear Physics, Russian Scientific Center "Kurchatovskii institut." Translated from Atomnaya énergiya, Vol. 76, No. 2, pp. 153–155, February, 1994.     

Use of Refractory Coatings in Systems for Melt Containment in a Serious Accident at a Nuclear Power Plant with a VVÉR Reactor

A computational analysis is performed of the use of zirconium dioxide ceramic in melt containment systems with relatively thin heat-conducting structures. The results of an investigation of the physicochemical processes for the interaction of melt with zirconium dioxide ceramic are presented. It is shown that the use of zirconium dioxide ceramic together with a passive water source gives the required melt cooling parameters for 3 to 24 h depending on the cooling regime. 4 figures, 9 references.     

Thermal–hydraulic modeling of water/Al2O3 nanofluid as the coolant in annular fuels for a typical VVER-1000 core

In this paper, a thermal–hydraulic analysis of nanofluid as the coolant is performed in a typical VVER-1000 reactor with internally and externally cooled annular fuel. The fuel assembly for annular case with 8 × 8 arrays is considered for annular pin configuration. The considered nanofluid is a mixture composed of water and particles of Al₂O₃ with various volume percentages. The fuel rod is modeled using a CFD code. To validate the calculated results, the present results of solid fuel with nanofluid and pure water are compared with other studies which have been done with visual FORTRAN language, DRAGON/DONJON code, COBRA-EN code and the mentioned analytical approaches have been validated by comparing with the final safety analysis report (FSAR). The comparison of the calculated results shows that the results are in good agreement with other studies. Thus, the accuracy of the validation is satisfactory. Moreover, the temperature distributions of the fuel, clad and coolant are described for water/Al₂O₃ nanofluid in solid fuel and annular fuel. It is observed that as the concentration of Al₂O₃ nanoparticles increases, due to higher heat transfer coefficient of Al₂O₃ nanofluid, the temperature of the coolant is increased and the central fuel temperature is reduced. Thus, it improves margin from peak fuel temperature to melting. Finally, it is illustrated the use of the annular fuel instead of solid fuel in core of the reactor, security and efficiency of the nuclear power plant will be increased.     

12C(α,α)12C resonant elastic scattering at 5.7 MeV as a tool for carbon quantification in silicon-based heterostructures

The incorporation of carbon into substitutional sites in Si or Si_1−xGe_x attracts increasing interest due to the enhanced possibilities in strain and band gap engineering of group IV heterostructures. Precise and accurate measurement of carbon concentration is, however, quite difficult to achieve. We focused our attention on the study of the alpha resonant elastic scattering in the 5.7 MeV energy region. We measured the scattering cross-section in the range 5.4–6.0 MeV at a laboratory scattering angle of 170°. The results indicate that the cross-section value is enhanced with respect to the Rutherford one of an almost constant factor (×130) in an energy interval about 100 keV wide. This allows a more accurate measurement of carbon concentration than with the normally used 4.265 MeV resonance. The experimental procedure to deal with non-Rutherford scattering of Si has been also determined. The resonant scattering at 5.72 MeV has been used, in combination with Rutherford Backscattering Spectrometry (RBS) at 3.0 MeV, to determine the carbon content of three Si_1−x−yGe_xC_y samples. This has also been used, in channelling geometry, to determine the substitutional carbon fraction of the samples.     

Swelling as a consequence of gamma prime (γ') and M23(C,Si)6 formation in neutron irradiated 316 stainless steel

An unexpected ordered phase, γ', found to be nominally Ni₃Si, was identified during the investigation of 20% CW 316 stainless steel irradiated to high neutron fluences. The γ' forms at temperatures below ~525°C and increases in volume function tion with fluence. While the emergence of this phase is coincident with the onset of substantial swelling, there is no direct association of voids and γ' particles. At temperatures higher than the γ' regime, other precipitates, including M₂₃(C, Si)₆ predominate. Void formation is also coincident with the emergence of the M₂₃(C, Si)₆ phase and usually involves a void-precipitate association. Formation of these precipitates depletes the austenite matrix of silicon and possibly other eleme which exert a strong influence on void nucleation. A model is presented which relates the high relative partial diffusivity silicon to a depression of the void nucleation rate. Removal of silicon from the matrix then leads to an enhanced nucleat rate.     

Maintaining an Equilibrium Offset as an Effective Method for Suppressing Xenon Oscillations in VVÉR-1000

A method is described for suppressing xenon oscillations of the vertical distribution of energy release in VVÉR-1000 by maintaining an instantaneous offset in accordance with the instantaneous vertical distribution of xenon nuclei along the reactor core. Computational examples of the suppression of oscillations are presented. 2 figures, 3 references.     

Characterization of a new shielding rubber for use in neutron–gamma mixed fields

A variety of formulations was investigated for the fabrication of an appropriate shielding rubber to be used in neutron–gamma mixed fields. Having considered the required mechanical properties together with tungsten as the gamma-ray absorbing element, calculations with MCNPX 2.6 code confirmed that the incorporation of 5 weight percentage(wt%) of boron carbide exhibited the best performance as a thermal neutron absorber. A series of both experimental and simulation results are provided for comparison.     

CFD analysis of the loss coefficient for a 90° bend in rolling motion

The local loss coefficient for a 90° bend in rolling motion is investigated with CFD code FLUENT. The calculation results are validated with experimental and theoretical results in steady state. The effect of spanwise and transverse additional forces on the bend loss is significant. The effects of additional forces on the bend loss are mainly embodied in the downstream section. The oscillation of bend loss caused by the spanwise and transverse additional forces is very regular while that caused by velocity oscillation is very irregular. The effect of velocity oscillation on the bend loss is significant in rolling motion with low Reynolds number. But the variation of bend loss coefficient with velocity oscillating period is very limited.     

Use of the alloy Na−K−Cs as a coolant in a fast reactor: Preliminary results of safety characteristics optimization

A possible variant of a safe reactor operating on fast neutrons and cooled by the alloy Na−K−Cs is examined. The results of optimization investigations of the layout of a fast reactor with constraints on the functionals characterizing the internal self-shielding from ATWS-type accidents are presented. 2 tables, 5 references. Moscow Engineering-Physics Institute. Translated from Atomnaya énergiya. Vol. 88, No. 3, pp. 169–176, March, 2000.