[en] In nearly 100 years' development of X-ray technique, synergy effects between medical technology and non-destructive material testing (NDT) have repeatedly led to new applications. Thus digital radiography in medicine is a 'low dose' process introduced years ago which, by using a specially developed storage foil technique, offers extensive possibilities of application for NDT. (orig.)

[en] Among inorganic crystalline luminescent compounds, X-ray luminophors are distinguished by the facts that their conversion efficiency is most sensitive to their intrinsic and impurity structural defects and that the quality of the image obtained by them depends to the greatest extent on the particle form and the perfection of their surface. Screens with calcium tungstate luminophors having oval particles with a smooth surface remain unsurpassable in image quality. The efficiency of this luminophor is 5-6%, whereas that of yttrium oxosulfide activated by terbium is nearly 13%. However, it should be noted that the quality of an image is determined not only by the shape of the particles and their packing in the luminophor layer, which depends on the manner of its formation, but also on the luminophor efficiency. An imperfect layer yields structural graininess of an image, and small doses attained at high efficiency produce so-called quantum graininess of an image. Thus, quantum fluctuations limit the tendency toward higher efficiency. Luminophors with an efficiency of 10-12% and with particles similar to those of calcium tungstate luminophor appear to be optimal for most roentgenographic trends in medicine. It is natural that these are only the necessary conditions for producing the open-quotes idealclose quotes X-ray screen because the formation of a perfect luminophor layer from such a luminophor is a separate problem

[en] Crystalline antimonic acid (C-SbA) showed an unique selectivity for microamounts of metal ions in nitric acid media. The ion-exchange isotherms of the systems of various metal ions/hydrogen ions have been studied on C-SbA. S-shaped isotherms were observed for most of the metal ions, indicating selectivity reversal. Kielland plots were close to straight lines with slopes correlated to the crystal ionic radii of the metal ions exchanged. In order to interpret the selectivities a hypothetical equilibrium constant was determined by extrapolating to zero loading of metal ions in C-SbA. From these values, thermodynamic data was calculated and evaluated. (author)

[en] A theoretical and experimental study on the dissolution of porous media by flowing acid has been carried out. Dissolution of the media results in an evolution of the pore geometry and the formation of random flow channels. The goal is to predict the range of conditions under which channels will form, and the effects of various parameters on the structure of the channels and on their rate of propagation through the media. A random network model is used to describe the behavior of the stochastic, rootlike channels that form during flow and dissolution in carbonate rock and in other systems. The structure of the flow channels that form as a result of acid attack are characterized and studied using a Wood's metal casting technique. A comparison of model results shows that the rates of channel formation and growth are intimately related to the developing structure of the channels (size of branches and degree of branching), which in turn is controlled by factors such as the fluid velocity and the rate of reaction. Depending on the experimental conditions, the channels range from a single conduit with a minimum of branching to a highly branched, spongy network of channels. The dependence of permeability increase and channel branchedness on injection rates and acid diffusion rates is described by the Damkohler number for flow and reaction

[en] Interpretation of new effects relating to deuterium substitution for hydrogen in weak molecular complexes containing A-H...B fragment is suggested. It is shown experimentally that the equilibrium length of the A-B fragment in case of the substitution mentioned does not increase, like in middle hydrogen bonds, but decreases. It has been detected that the strength constant of longitudinal intermolecular vibrations increases noticeably when D is substituted for H. New regularities in isotope effect for the frequency of A-H longitudinal vibration in the complex have been ascertained. Refs. 108, figs. 7

[en] N-Propylsulfamic acid supported onto magnetic Fe₃O₄ nanoparticles (MNPs-PSA) was used as an efficient and magnetically recoverable catalyst for synthesis of 2H-Indazolo[2,1-b]phthalazine-1,6,11(13H)-trione derivatives from the three-component, one-pot condensation reaction of phthalhydrazide, aromatic aldehydes and cyclic 1,3-diones, in good to excellent yields at 100 .deg. C under solvent-free conditions. The catalyst was easily separated with the assistance of an external magnetic field from the reaction mixture and reused for several consecutive runs without significant loss of its catalytic efficiency. In order to compare, the synthesis of 2H-Indazolo[2,1-b]phthalazine-1,6,11(13H)-trione derivatives in the presence of catalytic amount of sulfamic acid (SA) under same reaction condition was also reported

[en] We analyze the HCO⁺ 3-2 and H¹³CO⁺ 3-2 line profiles of 27 high-mass star-forming regions to identify asymmetries that are suggestive of mass inflow. Three quantitative measures of line asymmetry are used to indicate whether a line profile is blue, red, or neither-the ratio of the temperature of the blue and red peaks, the line skew, and the dimensionless parameter δv. We find nine HCO⁺ 3-2 line profiles with a significant blue asymmetry and four with significant red asymmetric profiles. Comparing our HCO⁺ 3-2 results to HCN 3-2 observations from Wu et al., we find that eight of the blue and three of the red have profiles with the same asymmetry in HCN. The eight sources with blue asymmetries in both tracers are considered strong candidates for inflow. Quantitative measures of the asymmetry (e.g., δv) tend to be larger for HCN. This, combined with possible HCO⁺ abundance enhancements in outflows, suggests that HCN may be a better tracer of inflow. Understanding the behavior of common molecular tracers like HCO⁺ in clumps of different masses is important for properly analyzing the line profiles seen in a sample of sources representing a broad range of clump masses. Such studies will soon be possible with the large number of sources with possible self-absorption seen in spectroscopic follow-up observations of clumps identified in the Bolocam Galactic Plane Survey.

[en] The correlation between the intensifying action of luminescent screens in radiography (the sensitivity of their combination with a film) and detail detectability on the image is considered. This connection is shown to depend on several factors including the applied range of spatial frequencies. A classification of intensifying screens is given according to their efficiency, and some examples for the practical use of the established regularities are considered. (author)

[en] A gamma ray camera is disclosed for detecting rays emanating from a radiation source such as an isotope. The gamma ray camera includes a sensor array formed of a visible light crystal for converting incident gamma rays to a plurality of corresponding visible light photons, and a photosensor array responsive to the visible light photons in order to form an electronic image of the radiation therefrom. The photosensor array is adapted to record an integrated amount of charge proportional to the incident gamma rays closest to it, and includes a transparent metallic layer, photodiode consisting of a p-i-n structure formed on one side of the transparent metallic layer, and comprising an upper p-type layer, an intermediate layer and a lower n-type layer. In the preferred mode, the scintillator crystal is composed essentially of a cesium iodide (CsI) crystal preferably doped with a predetermined amount impurity, and the p-type upper intermediate layers and said n-type layer are essentially composed of hydrogenated amorphous silicon (a-Si:H). The gamma ray camera further includes a collimator interposed between the radiation source and the sensor array, and a readout circuit formed on one side of the photosensor array. 6 figs

[en] Papers are presented on the cometary plasma, near-nucleus observations of P/Halley, scintillations of four radio sources occulted by the plasma tail of Comet Halley, and modeling of the excitation of molecules at radio wavelengths and the thermodynamics of the coma. Also considered are observations of HCN in Comet Halley, the search for parent molecules, the search for molecules in Comet Halley at millimeter wavelengths, and the OH radio lines in comets. Other topics include OH radio observations of Comet Halley from the Southern Hemisphere, radio OH observations of P/Halley with the NRAO 43-m telescope, models of the OH 18-cm line profiles of Comet Halley, and the first radio images of OH emission from Comet Halley