[en] The calculation of force field and valency frequencies of the B₂O₂ molecule is carried out on the basis of the measurements of isotopic structure of the band of B₂O₂ antisymmetrical valent vibration. It is found out (for ¹¹Ba₂¹⁶O₂), that ν₁=2060+-20, ν₂=585+-25 cm^-1

No abstract available

[en] Boron is oxidized in an oxygen-stream in the presence of a boride of platinum or of a metal of the same group at temperatures from 1250 to 1400 deg C care being taken to use as refractory support, a material not likely to re-act with boron at such temperatures. In particular, to boron can be added platinum in the finely-divided states, which is transformed into boride towards 100-110 deg C by using a plate of mullite. The platinum can be recovered later on by treating the product with ebullient dilute sulfuric acid. This can be applied to the manufacture of very hard cutting-edge tools, of refractory walls adapted to resist oxidization up to about 1400 deg C and even of neutron-shields used in certain atomic experiments

[en] Four kinds of BN powders--amorphous BN with B₂O₃, partially crystallized BN without B₂O₃, well-crystallized hBN with B₂O₃, and well-crystallized hBN without B₂O₃--were prepared to determine the effect of B₂O₃ on the crystallization of amorphous BN and the effect of BN crystallinity on the formation of cBN under high pressure (4--5 GPa) and at high temperature (1,350--1,450 C). The amorphous BN with B₂O₃ easily crystallized and transformed to cBN in the presence of AlN catalyst, while the partially crystallized Bn without B₂O₃ did not. The well-crystallized hBN transformed very slowly to cBN without B₂O₃, in contrast to fast transformation with B₂O₃. It is thus found that the transformation from hBN to cBN in the presence of AlN catalyst is determined by the degree of BN crystallinity as well as the presence of B₂O₃. Cubic BN can be synthesized only from crystallized hBN under the experimental conditions used. The formation of cBN from amorphous BN is possible through its prior crystallization, which can occur in the presence of B₂O₃

No abstract available

[en] Infrared (IR) spectroscopic investigation of binary silver borate glasses in the system xAg2 O. (1-x) B2 O3 for various values of x (0< x <0.77) has been performed in order to understand the glass modifying properties of Ag2 O. The IR spectra show clearly the disappearance of boroxol rings and the formation, in a first step, of tetraborate groups and later of diborate groups as the oxide content increases. For high Ag2 O content, borate groups with non-bridging oxygen atoms are formed

[en] Experimental results of stimulated nuclear spin echos decay in glasses are presented. The measurements were performed in B₂O₃ glasses, at the 23Na and ¹¹B resonance lines. The data analysis allows the study of Spectral diffusion at an inhomogeneous nuclear magnetic (NMR) resonance line, broadened for a desordered system of nuclear spins. A model is proposed to explain the time constants, and the particular form of the decay. (A.C.A.S.)

[en] Determined are the evaporation coefficients of the components of a glass-like system constituting boron oxide and germanium dioxide. Measurements were performed from the platinum channel and platinum effusion chamber of a low-temperature evaporator. Evaporation from the platinum channel was assumed to take place from an open surface in accord with Lengmuir, and that from the platinum chamber in accord with Knudsen. The evaporation coefficient was calculated on the basis of the Motzfeldt equation. In boron germanate glasses, the evaporation coefficient of germanium dioxide was shown to differ from the evaporation coefficient of pure germanium dioxide. Within the margin of error involved in the calculations, the evaporation coefficient of boron oxide coincides with the evaporation coefficient of pure boron oxide

[en] The invention concerns a spray nozzle, particularly for the decontamination of radioactive pieces with a jet composed of a mixture of water and abrasive particles. A detailed description of the nozzle is given. The process described here uses abrasive particles, soluble in water; as the dissolution is not instantaneous, the particles are in a solid form during the spray operation, then they dissolve. These abrasive particle are preferably boron trioxide

[en] In this paper we report a new theory that reproduces qualitatively well the Raman spectrum of v-B₂O₃. The basic idea is that one can find the thermodinamically averaged Green's function for a Bethe lattice, with a Born Hamiltonian, with dihedral angles totally random. In extension one constructs a Bethe lattice of rings and solve the equations of motion for Green's functions at the Boron sites, bridging oxygens and oxygens in the rings. (M.W.O.)