The absorption of deuterium by carbon-based facing materials on components in contact with the plasma in a thermonuclear reactor

Conclusions The conditions have been proposed for performing modeling experiments making it possible to predict the accumulation of hydrogen isotopes in carbon materials which are in contact with a tokamak plasma acting as a source of particles having a flux density of between 3×10¹⁶ and 3×10¹⁹ cm⁻²·sec⁻¹. By analyzing the reemission fluxes formed in the stopping zone of the particles implanted from the plasma it is suggested that the action of the plasma as regards the sorption of hydrogen is identical to that of annealing the material in an atmosphere of hydrogen isotopes at a pressure of 1–10³ Pa and a temperature of 1200–1700 K. The quantity of absorbed deuterium in POCO, UAM, RGT-B, and USB increases as the temperature is lowered and the pressure is raised (1500 K, 0.66 Pa→1200 K, 133 Pa). As regards their sorption of deuterium, POCO, UAM, and RGT behave similarly. There is a tendency for the sorption capacity of materials doped with boron to be reduced. In a class of itself is the isotropic material USB, whose sorption capacity is a factor of 10–100 lower than that of undoped graphite. The introduction into these materials of radiation-induced defects (T=300 K) by means of ion irradiation in the range 0.1–1 dpa results in a continuous rise in the deuterium sorption capacity by a factor of 10–100 (up to 10⁻² atomic fraction). The USB graphite demonstrates record low increments in the sorption capacity. In the fluence range identical to 1–10 dpa the sorption capacity of carbon materials for hydrogen is almost constant. The process of the sorption of hydrogen isotopes can be described as the filling of two ensembles of traps, deep traps which are difficult to access and readily accessible Langmuir traps. In the RGT-B materials containing 0.1% of boron, the traps introduced by irradiation with 300-keV neon ions vanish on annealing in a vacuum (T=1800 K, t=1 min). Institute of Physical Chemistry, Russian Academy of Sciences. SINTEZ Scientific and Technical Center, Scientific-Research Institute of Electrophysical Apparatus. Graphite Scientific-Research Institute. National Scientific Center, Kharkov Physicotechnical Institute. Translated from Atomnaya énergiya, Vol. 82, No. 6, pp. 448–464, June, 1997.     

Phase relations in the system ln-CulnS2

By DTA and x-ray diffraction the phase relations in the pseudobinary system In-CuInS₂ have been investigated. CuInS₂ hs a melting point of 1090° C and within this system there is a broad region of liquid immiscibility. A four phase invariant reaction exists at 633° C which is of the form: L₂ = L₁+ CuInS₂ + InS.     

How great is radiation exposure in the area surrounding patients after administration ov 99mTc-sestamibi?

AIM: The aim of the present study was to estimate the additional radiation exposure to personnel, other patients and members of the family caused by patients who had been injected with 99mTc-Sestamibi (Cardiolite DuPONT PHARMA) for preoperative localization of parathyroid adenoma. METHODS: Dose rates were measured from 16 patients who had received an intravenous injection of 600 +/- 50 MBq 99mTc-Sestamibi. All measurements were performed with a portable dosimeter (Berthold LB 133) at 3 different distances (0.5, 1 and 2 m) at 10 min, 180-200 min and 24 h after administration of the tracer. RESULTS: The dose rates amounted to 20.5 microSv/h at 0.5 m, 5.25 microSv/h at 1 m and 1.55 microSv/h at 2 m distance from patients respectively. The biological half-life was 54 h. The calculated maximal dose to other persons in the waiting area was 31.2 microSv, to family members 27.6 microSv and to nurses in a ward 31.2 microSv. CONCLUSION: Our results indicate that the calculated maximal radiation exposure for personnel, family members and other patients even under very unfavourable conditions was below the maximal allowed dose for non-professionally exposed persons.     

Synthesis of a Bi2Sr2CaCu2Oy high-temperature superconducting phase with T c ° above 100 K

A high-temperature superconductor with the Bi₂Sr₂CaCu₂O_y structure and a superconducting transition temperature _{T c} ^° =102–107 K has been synthesized. The synthesis conditions are described and results of a phase analysis, and of resistive and inductive measurements are reported. Pis’ma Zh. Tekh. Fiz. 23, 17–22 (June 12, 1997)     

Air-atomized iron powders — past, present, future

This article examines the history and future prospects of the production of iron powders by the atomizing high-carbon melts with compressed air. In terms of their properties, the iron powders obtained by this method are intermediate between water-atomized powders and reduced powders. They can be used to make anti-friction products or structural elements having a density within the range 6.3–6.9 g/cm³. The outlook for these powders is promising in Russia because they are needed for machine construction, especially in the auto industry.     

Improved strained HEMT characteristics using double-heterojunctionIn0.65Ga0.35As/In0.52Al0.48As design

The DC and microwave properties of strained In_0.65Ga _0.35As/In₀₅₂Al_0.48As HEMTs (high electron-mobility transistors) with double-heterojunction design are presented. The high sheet carrier density and good carrier confinement give rise to excellent device performance with very low output conductance. For 1×150-μm² long-gate HEMTs, the measured cutoff frequency f_T and maximum frequency of oscillation f_max are as high as 37 and 66 GHz, respectively