The actual problem of modeling machine tools geometrical errors influence on machined surfaces precision is considered in the paper. The turning as an example of the treatment type is considered ...because it has the highest prevalence. The mathematical model of the machined surfaces accuracy is set and the model takes into account the influence of machine tools geometrical errors. The basis for the mathematical model creation was the application of the variational method development for calculating of the metal cutting machines accuracy. The mathematical model of the cylindrical and end surfaces turning precision is proposed in this work. The lathe processing accuracy is simulated at constant values of the turning machine geometrical errors for presented typical surfaces. The direction of future research of the processing accuracy simulation is identified for the values of geometric errors which are associated with the coordinate motion of the machine components. The directions for further studies of the turning accuracy at variable geometric errors of the turning machine are suggested. The work is useful for scientists involved in the study of the metalworking accuracy.
The work presents the results of a study of the negative photochromism and luminescent properties of 1',3'-dihydro-3',3'-dimethyl-6-nitro-1'-octadecyl-1-benzopyran-2,2'-indole-8-methyl pyridinium ...chloride (SP2) in solutions, Langmuir monolayers, and cast films. It has been demonstrated that the introduction of the pyridine substituent into the chromene part of the amphiphilic spiropyran leads to stabilization of the open form of the compound under dark conditions, both in the dissolved and in the ordered planar state. The kinetic characteristics of photoreactions occurring in organic solvents upon irradiation by visible light and during relaxation in darkness are determined. Negative solvatochromism of SP2, which consists in the hypsochromic shift of the maximum absorption of the merocyanine form of the compound upon increase of the solvent polarity, is revealed. The luminescent properties of solutions of negative spiropyran and its cast films are investigated. For the first time, SP2 monolayers are formed at the air/water interface and their properties are studied. It is established that SP2 retains its photochromic properties upon transition from solutions to a two-dimensional condensed state. The results obtained open up broad prospects for the development of switchable optoelectronic and information systems based on negative spiropyrans.
Samples of a multifilament thread based on refractory oxides according to the sol-gel method have been produced. Technological defects typical for the fibers of the produced thread have been ...investigated. The detected fiber defects have been classified and recommendations for their elimination have been given, which will increase the tensile strength of the fibers.
Boron-doped diamond single crystals of cubo-octahedral habit have been obtained by temperature gradient method at high pressures and high temperatures (HPHT) in Fe-Al-B-C system, and multisectoral ...plates of different orientations have been produced. Spatial distribution of uncompensated boron impurity and surface potential through the interfaces of different growth sectors of diamond plates have been studied by scanning Fourier transform infrared (FTIR) and Raman micro-spectroscopy, as well as scanning spreading resistance microscopy (SSRM) and Kelvin-probe force microscopy (KPFM). FTIR mapping showed strongly non-uniform growth-sector dependent distribution of uncompensated boron impurity gradually decreasing in a sequence {111} → {110} → {113} → {001} from ~7 · 1018 cm−3 down to 2 · 1017 cm−3. Micro-Raman mapping is used to reveal the submicron distribution of structural quality and boron content through the interfaces of different growth sectors. The inter-sectoral jumps of the surface potential in the axial and radial directions of the growth sectors were studied by KPFM, their theoretical estimates are obtained, and the features of the band structure of the inter-sector interfaces are revealed. A high level of structural perfection of inter-sectoral boundaries without electrically active defects is demonstrated.
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•High structural quality of HPHT-diamond single crystals with a cubo-octahedral habit synthesized in the Fe-Al-B-C growth system is demonstrated.•Significant inter-sectoral heterogeneity of boron content decreasing from ~7·1018 cm−3 to ~2·1017 cm−3 in a sequence {111} → {110} → {113} → {001} is shown.•Quantitative difference in electric potential between different growth sectors of boron doped HPHT diamonds was estimated.•Clear coherent inter-sectoral boundaries with step-like difference in electric potential are promising for the development of dedicated diamond-based electronic devices.
Ceramic fibers of refractory oxides used as the main components of heat-resistant refractory materials are discussed. External defects affect the mechanical characteristics of refractory oxide ...ceramic fibers. Optical and electron microscopy were used to investigate the surface morphology of ceramic fibers, to classify the defects, to establish the causes for their appearance, and to propose methods for eliminating them.
We have studied large (∼6-mm diameter) single crystals of semiconducting synthetic diamonds seed—grown by the temperature-gradient method. EPR, IR spectroscopy and cathodoluminescence have been used ...to examine the defect and impurity composition of the crystals and the distribution of the electrically active impurities in the bulk crystal. Electrophysical measurements of the current–voltage characteristics and temperature dependence of electrical conductivity have been conducted. Contrast in the internal electric fields caused by inhomogeneity in the distribution of acceptor and donor centers is shown to play the decisive role in the electrical properties. Our findings point to considerable promise for the use of the temperature-gradient method to grow large semiconducting diamond single crystals (of the IIb type) with the required electrical properties as well as to the possibility to extend the application of such crystals (or their fragments) to electronics.
Although economic growth leads to a reduction in poverty, the growing income inequality and its possible consequences are of some concern. The level of economic complexity has recently been ...increasingly viewed as an important predictor of income inequality. In this paper, using pool and models with time fixed effects, the impact of the economic complexity index on income inequality in Russian regions for 2013 and 2015 was estimated. The results of the evaluation of econometric models show that regions with more complex economies showed a higher level of income inequality compared to others. The explanations for the effect obtained include an increase in demand for highly qualified labor as a result of the development of high-tech industries and an increase in wage differentiation between high-skilled and low-skilled workers, as well as the migration of high-skilled workers to economically more complex regions. The main conclusion is that economic complexity is a significant factor of the variation in income inequality and should also be taken into account while conducting economic and social policy in Russian regions.
A mathematical model of the vibrations of a production system for the turning of blanks is presented. Results of comparative analysis of processes employed for the turning of steel-45 and caprolon ...blanks are presented. The relationship between the mean-arithmetic deviation of the profile of the machined surface of caprolon articles from the maximum values of the energy spectrum of vibration accelerations and the vibration frequencies of the production system corresponding to them during the machining of blanks is established experimentally.
A new method is described for molding epoxy resin objects. Results are provided for polymer body structural studies by scanning electron microscopy and infrared spectroscopy. Results are also ...provided for mechanical and manufacturing tests confirming the expediency and efficiency of including in the production process for manufacture of fiberglass objects combined treatment of polymer binder with nanosecond electromagnetic pulses and an electromagnetic field preceding hardening.
The synthesis of 1 : 1 and 1 : 2 complexes of Zn(
ii
) hexafluoroacetylacetonate with sterically crowded triphenodioxazines (TPDO) is described, and the compounds are characterized using ...single-crystal X-ray crystallography, NMR, and IR spectroscopy. The electronic absorption (
λ
max
= 530-630 nm) and fluorescence emission (
λ
fl
max
= 585-660 nm) spectra of the complexes substantially (up to 100 nm) bathochromically shifted relative to the spectra of the TPDO ligands. In highly dilute solutions, the Zn(hfac)
2
-TPDO complexes partially dissociate and exist in equilibrium with the ligand to reveal unusual excitation-dependent behavior of their fluorescent spectra.
The synthesis of 1 : 1 and 1 : 2 complexes of Zn(
ii
) hexafluoroacetylacetonate with sterically crowded triphenodioxazines (TPDO) is described, and the compounds are characterized using single-crystal X-ray crystallography, NMR, and IR spectroscopy.
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