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[en] Acoustic properties of alloys of Ge-Pb system have been studied. The temperature dependencies of ultrasound propagation velocity in alloys of Ge-Pb system were investigated in detail. It has been defined that the melting temperature of germanium is 1211 K and lead - 600 K. Based on conducted studies it has been shown that ultrasound propagation velocity depending on temperature decreases linearly.
[en] It is becoming more important to measure the pressure in high temperature environments in many industrial fields. However, there is no appropriate evaluation system and compensation method for high temperature pressure sensors since most pressure standards have been established at room temperature. In order to evaluate the high temperature pressure sensors used in harsh environments, such as high temperatures above 250 deg. C, a specialized system has been constructed and evaluated in this study. The pressure standard established at room temperature is connected to a high temperature pressure sensor through a chiller. The sensor can be evaluated in conditions of changing standard pressures at constant temperatures and of changing temperatures at constant pressures. According to the evaluation conditions, two compensation methods are proposed to eliminate deviation due to sensitivity changes and nonlinear behaviors except thermal hysteresis.
[en] In the pre-dose technique, the change in 110 degree C TL sensitivity with dose is generally represented by a linear function. But it was found that the growth of sensitivity with dose was sublinear even if dose was less than a few Gy on porcelain and pottery. According to the saturating exponential characteristic of archaeological samples, a new method for evaluating paleo-dose was studied. In addition, a correction for the radiation quenching was made
[en] We present quantum calculations of the relaxation matrix for the Q branch of N2 at room temperature using a recently proposed N2-N2 rigid rotor potential. Close coupling calculations were complemented by coupled states studies at high energies and provide about 10 200 two-body state-to state cross sections from which the needed one-body cross-sections may be obtained. For such temperatures, convergence has to be thoroughly analyzed since such conditions are close to the limit of current computational feasibility. This has been done using complementary calculations based on the energy corrected sudden formalism. Agreement of these quantum predictions with experimental data is good, but the main goal of this work is to provide a benchmark relaxation matrix for testing more approximate methods which remain of a great utility for complex molecular systems at room (and higher) temperatures
[en] The formation and dissociation rates of Zn2+ complexes with 1,4,7,10-tetraaza-13,16-diox-acyclooctadecane-N,N',N'',N'''-tetraacetic acid (1), 1,4,7,10-tetraaza-13,16- dioxacyclooctadecane-N,N',N'',N'''-tetramethylacetic acid (2), and 1,4,7,10-tetraaza-13,16- dioxacyclooctadecane-N,N',N'',N'''-tetrapropionic acid (3) have been measured by stopped-flow and conventional spectrophotometry. Observations were made at 25.0±0.1 .deg. C and at an ionic strength of 0.10 M NaClO4. The formation reactions of Zn2+ ion with 1 and 2 took place by the rapid formation of an intermediate complex (ZnH3L+) in which the Zn2+ ion is incompletely coordinated. This might then lead to be a final product in the rate-determining step. In the pH range 4.76-5.76, the diprotonated (H2L2-) form is the kinetically active species despite of its low concentration. The stability constants (logK(ZnH3L+)) and specific water-assisted rate constants (kOH) of intermediate complexes have been determined from the kinetic data. The dissociation reaction of Zn2+ complexes of 1, 2, and 3 were investigated with Cu2+ ions as a scavenger in acetate buffer. All complexes exhibit acid-independent and acid -catalyzed contributions. The effect of buffer and Cu2+ concentration on the dissociation rate has also been investigated. The ligand effect on the dissociation rate of Zn2+ complexes is discussed in terms of the side-pendant arms and the chelate ring sizes of the ligands
[en] Results of physicochemical study of the process of dispersion of intermetallic compounds formed by scandium, yttrium, rare earth and transition 3d-metals under the influence of hydrogen and pressure of 0.1-10 MPa and at temperatures of 273-623 K are presented and discussed. On the basis of data of X-ray phase, granulometric analyses, measurement of the value of specific surface, optimal and electron microscopy different variants of dispersion of intermetallic compounds in the above-mentioned conditions are considered
[en] A new concept 'soft solution processing' has been introduced to fabricate advanced solid state materials in an economical, environmentally friendly, and energy and material efficient way. The prepared films show the desired and prospective prospective properties despite of low temperature synthesis and no post-synthesis annealing. Successful examples demonstrate that soft solution processing is capable of preparing advanced materials with planned properties through the easy control of reaction conditions in a suitable aqueous solution in a single synthetic step without huge energy consumption and without any sophisticated equipment
[en] Laser-induced breakdown spectroscopy was evaluated for the analysis of the structure of laminar premixed methane–air flames. Firstly, breakdown threshold pulse energy and plasma energy in different areas of the flame were measured simultaneously, and an approximate linear relation between them was detected. Secondly, a new approach was proposed to qualitatively characterize the flame temperature distributions based on the plasma energy distributions. Finally, combination of the spatial analysis of the spectrum intensity, plasma energy and equivalence ratio, the laminar premixed flames structure was investigated deeply, including the distribution of the flame temperature, the width and distribution of different flame region (e.g. premixed combustion regions, high temperature regions.),as well as the location of the flame front. - Highlights: • LIBS was evaluated for the analysis of the structure of laminar premixed methane–air flames. • A new approach was proposed to characterize the flame temperature distributions based on the plasma energy distributions. • The laminar premixed flames structure was deeply studied to understand the combustion process.
[en] Atomic force microscopy (AFM) can now not only image individual atoms but also construct atom letters using atom manipulation method even at room temperature (RT). Therefore, the AFM is the second generation atomic tool following the scanning tunneling microscopy (STM). However the AFM can image even insulating atoms, and also directly measure/map the atomic force and potential at the atomic scale. Noting these advantages, we have been developing a bottom-up nanostructuring system at RT based on the AFM. It can identify chemical species of individual atoms and then manipulate selected atom species to the predesigned site one-by-one to assemble complex nanostructures consisted of multi atom species at RT. Here we introduce our results toward atom-by-atom assembly of composite nanostructures based on the AFM at RT including the latest result on atom gating of nano-space for atom-by-atom creation of atom clusters at RT for semiconductor surfaces
[en] To design the high-resolution magnetic force microscopy (MFM) tips suitable for high-density magnetic recording media with low bit aspect ratio (BAR), the transfer functions of tips with various sharpened tip-ends were calculated for a checkered perpendicular magnetization pattern and the resolution of these tips was estimated by considering the resolution limit due to thermal noise at room temperature. The cylindrical tip with a spheroidal tip-end having a large ellipticity is found to be a suitable candidate for high-resolution MFM imaging of magnetic recording media with low BAR. For the tips with ellipticities larger than tan 45 deg., there are no zero-signal frequencies. The sensitivity shows a maximum around an ellipticity of tan 70 deg. The spheroidal tip shows a much smaller tip thickness dependence compared to the bar shape tip with a flat tip-end or an ellipsoidal tip-end, because only the tip-end mainly contributes to signals in case of the spheroidal tip