On the nature op continuum emission production op photons,emitted by the products op repractory metal sputtering

Bombardment of a clean Ta target by 4 keV Cs⁺ ions under ultra high vacuum (UHV) has been experimentally shown to give rise to photon continuum emission by sputtered products.     

Reduced osteoblastic population and defective mineralization in osteopetrotic (op/op) mice

Osteopetrotic (op/op) mice fail to exhibit bone remodeling because of a defective osteoclast formation due to a lack of macrophage colony-stimulating factor. In this study, we investigated the femora of op/op mice to clarify whether the osteoblastic population and bone mineralization are involved in osteoclasts or their bone resorption. The op/op mice extended the meshwork of trabecular bones from the chondro-osseous junction to the diaphyseal region. In the femoral metaphyses of op/op mice, intense alkaline phosphatase (ALPase)-positive osteoblasts were observed on the metaphyseal bone in close proximity to the erosion zone of the growth plates. Von Kossa's staining revealed scattered mineralized nodules and a fine meshwork of mineralized bone matrices while the wild-type littermates developed well-mineralized trabeculae parallel to the longitudinal axis. In contrast to the metaphysis, some op/op diaphyses showed flattened osteoblasts with weak ALPase-positivity, and the other diaphyses displayed bone surfaces without a covering by osteoblasts. It is likely, therefore, that the osteoblastic population and activity were lessened in the op/op diaphyses. Despite the osteopetrotic model, von Kossa's staining demonstrated patchy unmineralized areas in the op/op diaphyses, indicating that a lower population and/or the activity of osteoblasts resulted in defective mineralization in the bone. Transmission electron microscopy disclosed few osteoblasts on the diaphyseal bones, and instead, bone marrow cells and vascular endothelial cells were often attached to the unmineralized bone. Osteocytes were embedded in the unmineralized bone matrix. Thus, osteoclasts appear to be involved in the osteoblastic population and activity as well as subsequent bone mineralization.     

Study op electrical conductivity op some chalkogenide glasses under hydrostatic pressure up to 1000 MPa

The study of electrical properties of amorphous materials under high pressure can contribute to understanding of processes in these materials and helps to build the theory of amorphous materials. Properties of these materials under high pressure are studied for instance in papers /1–6/. The change of electrical conductivity is usually ascribed to the change of activation energy due to hydrostatic pressure.     

Probe diagnostics op the planar magnetron discharge

Magnetron discharge during Ti sputtering was examined by Langmuir probe. Electron densities and energies were determined at different Ar pressures, dc. powers and distances from magnetron target. Values in order of 10¹⁵m^–3 and 1eV were measured even at distances up to 15 cm.The authors are grateful to Ing. J. Musil, DrSc. and Ing. A. prachta, CSc. for supporting this work. Helpful discussion with RNDr. S. Kadlec are also gratefully acknowledged.     

Thermal expansion op NbSe2 and TaS2

The lattice parameters a₀ and c₀ of the hexagonal 2H polytype of NbSe₂; have been measured over the temperature range 156–478 K for a₀, and 138–482 K for c₀. The lattice parameter c₀ of the hexagonal 2H polytype of TaS₂ has been measured between 151 and 472 K. The lattice parameters a₀ and c₀ for the octahedral 1T polytype of TaS₂ been measured between 165 and 488 K. Over these temperature ranges, the following average coefficients of thermal expansion have been measured; 2H-NbSe₂, 6.6 × 10^?6K^?1 along the a-axis, 19.9 × 10^?6 K^?1 along the c-axis; 2H-TaS₂, 15.6 × 10^?6 K^?1 along the c-axis; IT-TaS₂, 12.7 × 10^?6 K^?1 along the c-axis. The parameter c₀ of 1T-TaS₂ undergoes two transitions which may be explained in terms of charge density waves.     

ESR studies op irradiated aqueous solutions of hydroxypyrimidines

The irradiated aqueous solutions of 4-hydroxypyrimidine and 2-hydroxypyrimidine hydrochloride were examined by means of the In situ radiolysis steady-etate ESR method. One and three short-lived radicals respectively were detected in alkaline solutions. The struotures and reaction mechanisms of radicals were derived. The spin density distributions were calculated by the improved McConnell's relationships and the value of coupling factor Q^H _NC was determined.     

Study of the nonstoichiometric composition op zinc oxide

The x values in the nonstoichiometrie chemical formula Zn_1+xO have been measured in the temperature range from 400 to 1200°C under oxygen pressures from 1 to 10^?6 atm, and also 1 atm of air. The x values varied between 0.00824 and 0.06370 under the various oxygen pressures. The enthalpies of formation of excess zinc in zinc oxide were in general less than 7.40 kcal/mole under the above conditions, all positive values representing an endothennic process. The plots of log x vs log P_o2 (or log x = 1/n log P_o2) are linear, and the 1/n values from the slopes of the plots are $\text{?1}\text{14.0}\text{to}\text{?1}\text{11.1}$ in the temperature range 400–900°C. Many physical properties of zinc oxide such as electrical conductivity, catalytic effects and defects can be explained on the basis of the x values and the mechanism of formation of the nonstoichiometric compositions of the oxide.     

Determination op energy gap width in some semi-conductors

The formula derived by the author for the width of the energy gap is compared with experiment for GaSb, InAs, InSb, and InSb. GaSb semi-conductors. The agreement is good.

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GaSb, InAs, InSb, InSb. GaSb. o.

     

Chemical etching op fission tracks in ethylene-tetrafluoroethylene copolymer

The chemical etching of fission tracks in ethylene-tetrafluoro-ethylene copolymer was studied. Etched holes 3000–4000 Å in diameter was recognized by electron microscopy for a film bombarded by fission fragments in oxygen and etched in a 12N sodium hydroxide solution at 125°C. The radial etching rate at 125°C was 6–8 Å/hr, which is less than 17 Å/hr for polyvinylidene fluoride in the same sodium hydroxide concentration at 85°C. The smaller rate is a reflection of the larger chemical resistivity of ethylene-tetrafluoro-ethylene copolymer than polyvinylidene fluoride.     

Ion bombardment enhanced mixing op silver layers on silicon

Abstract - Silver films evaporated onto silicon substrates were sputtered by 35 keV Ar⁺ ions at different fluences and the evolution of the Ag depth profile was monitored by means of high resolution Rutherford backscattering. Evidence for bombardment-induced intermixing was found. Radiation-enhanced diffusion does not appear to be a major mechanism but at this stage we cannot determine the precise nature of the dominating mechanism.     

光声光谱法研究光学薄膜的吸收特性

本文以“一维热流活塞模型”为基础,推导出薄膜光声表达式,光声信号的幅值正比于吸收率.测量了透明基底上光学薄膜的光声吸收谱,实验结果与理论一致.尤其是测量弱吸收薄膜的吸收谱时,具有较高的灵敏度和实用性.