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[en] Within a revival of interest in the emission properties of Tl+-like impurity centers in alkali-halide crystals, the problem of a complete interpretation of high-energy and low-energy emissions in the A-band of KCl:Tl remains without a satisfactory explanation. Two previous works reported experimental results relative to spectral and decay-time measurements for low-energy (weak) emission at 475 nm, and for high-energy emission at 300 nm. In the latter case, however, a confirmation of the existence of an anomalous type of behavior in the slow decay time needed to be clarified. The results reported here demonstrate that this anomaly is not present in high-energy emission. On the basis of these more recent experimental results, an attempt is made to obtain a unifying model, one always based on the Jahn–Teller effect, which could serve in interpreting both high- and low-energy emissions.
[en] Optically stimulated luminescence (OSL) of pure analytical potassium chloride (KCl) prepared in two different forms (crystals and pellets) was studied. The occurrence of regeneration effect (self-renewal of the OSL signal) in the material was examined. The experiments using the variable delay OSL (VD-OSL) method were carried out. Performed measurements allowed to determine time scale of the phenomenon, as well as quantitative changes of regeneration depending on thermal treatment before and after irradiation. Significant increase of the OSL regeneration was noticeable for pellets after the application of the annealing before irradiation, while for crystals a substantial decrease of regeneration was observed. Preheating applied after irradiation caused that self-renewal of OSL signal was drastically reduced or completely suppressed depending on the form of KCl samples. - Highlights: • Optically stimulated luminescence (OSL) of potassium chloride (KCl) was studied. • The measurements were performed using the variable delay OSL method (VD-OSL). • It was found that regeneration of OSL intensity in KCl could be as high as 2000%. • Annealing caused reduction of OSL renewal for crystals and its increase for pellets. • Preheating after irradiation removed or significantly reduced the OSL regeneration.
[en] Highlights: • The energy landscapes of vacancy diffusion in ionic nano particles are revealed. • Topological features of the landscapes are visualized by a graph-based analysis. • The most probable paths of vacancy migration enhanced by the surface are identified. • Size-dependence of diffusion rate is characterized by mean first-passage time. Size dependence of vacancy migration energy in ionic nano particles is investigated by analysis of potential energy surfaces in potassium chloride clusters. Numerical methods are used to find almost all local minima and transition states for vacancy migration in clusters of different sizes, and reveal characteristic features of energy surface structure. It is shown that migration energy is significantly lower near a cluster surface than near a cluster core, and the mean first-passage time for migration of a vacancy decreases with cluster size. These results are consistent with observations of high diffusion rates in small clusters.
[en] Three-dimensional dynamic force spectroscopy measurements were carried out above KBr(001) at low temperature in order to investigate the distance dependence of the tip–sample interactions. In particular, the recorded 3D frequency shift data as well as the extracted interaction force and potential energy fields were analysed with respect to influences of tip and/or sample deformations. We found that a postprocessing correction of the observed deformations significantly modifies the magnitude of the extracted interaction forces and also the image contrast. (paper)
[en] Bromide is a conservative tracer that is often applied with non-conservative solutes such as pesticides to estimate their retardation in the soil. It has been applied in concentrations of up to 250 g Br L−1, levels at which the growth of single-celled organisms can be inhibited. Bromide applications may therefore affect the biodegradation of non-conservative solutes in soil. The present study investigated the effect of potassium bromide (KBr) on the mineralisation of three pesticides – glyphosate, MCPA and metribuzin – in four agricultural A-horizon soils. KBr was added to soil microcosms at concentrations of 0, 0.5, 2.5 and 5 g Br− L−1 in the soil solution. The study concluded that KBr had a negative effect on pesticide mineralisation. The inhibitory effect varied depending on the KBr concentration, the type of pesticide and the type of soil. Furthermore, 16 S amplicon sequencing revealed that the KBr treatment generally reduced the abundance of bacteroidetes and proteobacteria on both an RNA and DNA level. Therefore, in order to reduce the effect of KBr on the soil bacterial community and consequently also on xenobiotic degradation, it is recommended that KBr be applied in a concentration that does not exceed 0.5 g Br− L−1 in the soil water. - Highlights: • Conservative tracer KBr inhibits pesticide degradation. • The inhibitory effect depends on KBr concentration, type of pesticide and soil type. • KBr treatments generally reduced soil bacterial presence and activity. - This study reveals that KBr has a negative effect on herbicide mineralization, hence questioning if KBr should be considered concervative when used alongside xenobiotics in leaching experiments.
[en] Internal exposure dose by particle inhalation can be estimated by Human Respiratory Tract Model (HRTM) in Publication 66 of the International Commission on Radiological Protection (ICRP). According to HRTM, radiation dose by particle inhalation containing NORM depends on particle properties. ICRP provides the reference values which can be applied if it is impossible to measure the particle properties. However, when using these values, there can be a large difference with actual dose assessment. Consequently, the ICRP recommends that site-specific information on aerosol physic-chemical properties should be measured and then used in the worker dose assessment. Therefore, the actual measurement data of particle properties is required for reliable dose assessment. This study estimated the particle size distribution, particle concentration, density, shape, chemical composition and radioactivity concentrations. In this study, we evaluated the properties of the particles generated from the potassium chloride industry treating a large amount of materials containing natural radioactive nuclides in Korea. The characteristic values of the particles measured will contribute to internal exposure radiation dose assessment by particle inhalation of the workers. Furthermore, it can provide a reasonable means of radiation protection as basic data for establishing a system of natural radiation safety management
[en] In this article, a fractal concept is used to evaluate the morphological features of KBr layers, deposited in a controlled vacuum environment. To the best of our knowledge, for the first time, self-affine or self similar nature of KBr film surfaces was examined by autocorrelation function. Theoretical estimations revealed that irregularity/complexity of growing KBr layers was significantly influenced by the thickness. The global interface width and lateral correlation length were monotonically decreased with increasing film thickness. On the contrary, fractal dimension and local roughness exponent, estimated by height-height correlation function, did not suggest such dependency. (paper)
[en] This study was aimed to find the effects of various molar concentrations of KCl (0.1M, 0.2M, 0.3M and 0.4M) on some growth parameters of Solanum melongena L. (eggplant). The parameters included stem height, leaf length, number of leaves, fresh and dry weight of plant, width of leaf and length of root index were investigated. The plant which is subjected to the highest concentration of KCl drastically effects the plant life cycle as well as productivity of plant. Much of the healthy and strongest plant is formed in control condition as compare to these which received KCl with different concentration. Salinity stress significantly decreased average height of shoot i.e. 30.53cm in control while the least i.e. 10.2cm at 0.4 conc. of KCl. Similarly, average number of leaves i.e. 17.43cm in control while the least i.e. 5.01 at 0.4 conc. of KCl. Likewise average length of leaf i.e. 18.04cm in control while the least i.e. 9.96cm at 0.4 conc. of KCl. Average Fresh and dry weight of plant i.e. 27.96g and 9.12g respectively in control while the least i.e. 7.01g and 2.025g at 0.4 conc. of KCl. Similarly average width of leaf i.e. 7.88cm in control while the least i.e. 3.88cm at 0.4 conc. of KCl. Likewise average length of root i.e. 18.75cm in control while the least i.e. 6.90cm at 0.4 conc. of KCl. These indexes show the same response to different concentration of KCl which means that the concentration and the response of the above indexes are inversely proportional to each other. Greater the concentration of KCl lower will be the response of the above indexes and vice versa. (author)
[en] Recent advances in non-contact atomic force microscopy (nc-AFM) have led to the possibility of achieving unprecedented resolution within molecular structures, accomplished by probing short-range repulsive interaction forces. Here we investigate C60 molecules adsorbed on KBr(111) and Cu(111) by tuning-fork-based nc-AFM. First, measurements of C60 deposited on KBr(001) were conducted in cryogenic conditions revealing highly resolved nc-AFM images of the self-assembly. Using constant-frequency shift mode as well as three-dimensional spectroscopic measurements, we observe that the relatively weak molecule-substrate interaction generally leads to the disruption of molecular assembled structures when the tip is probing the short-range force regime. This particular issue hindered us in resolving the chemical structure of this molecule on the KBr surface. To obtain a better anchoring of C60 molecules, nc-AFM measurements were performed on Cu(111). Sub-molecular resolutions within the molecules was achieved which allowed a direct and unambiguous visualization of their orientations on the supporting substrate. Furthermore, three-dimensional spectroscopic measurements of simultaneous force and current have been performed above the single molecules giving information of the C60 molecular orientation as well as its local conductivity. We further discuss the different imaging modes in nc-AFM such as constant-frequency shift nc-AFM, constant-height nc-AFM and constant-current nc-AFM as well as three-dimensional spectroscopic measurement (3D-DFS) employed to achieve such resolution at the sub-molecular scale. (paper)
[en] X ray irradiates material for dose distribution confirmation through material color variation to evaluate about possibility. That is rare earth material to pure KCl and KCl impurity Eu adding 0.5 mol% by Czochralski method each single crystal grow and observed color variation of KCl X ray irradiation use of linear accelerator. High energy X ray irradiation KCl:Eu show the blue fluorescence with purple color that pure KCl single crystal can confirm by show was not observed, but was colored violet. Colors variation of KCl founds stable color center from radiation and this color variation will be used usefully to X ray measurement material and phantom.