Search Results
You are looking at 1 - 10 of 15 items for
- Author or Editor: D. M. Petrović x
- Refine by Access: All Content x
Abstract
The paper describes the results of differential thermal analysis of the octahedral Fe(III) complexes of the general formula [Fe(HLn)2]Cl and Fe(HL3)L3, as well as of the corresponding ligands H2Ln (H2Ln — tridentate salicylaldehyde semi thiosemi- and S-methylisothiosemi-carabazones with n=1, 2 and 3 respectively). The decomposition of the complexes involving sulphur-containing ligands (H2L2 and H2L3) starts with sulphur elimination. In case of the complexes [Fe(HL2)]Cl and [Fe(HL3)]Cl sulphur evolves independently, whereas with Fe(HL3)L3 it is eliminated within the SCH3 group. In the former case, sulphur elimination takes place at the same temperature for both complexes. The change in the coordination mode, being a consequence of the replacement of O by S, has no essential effect on thermal stability of the coordination polyhedron. The complexes involving ONN coordination, realized with the H2L3 ligand, exhibit a comparatively highest thermal stability of the coordination polyhedron.
The unit cell parameters and the space group of the investigated compound were determined by means of X-ray diffraction.
Summary
The paper describes the results of a study of glasses of the type CuxAs50Se50-xfor x=5, 10 and 15 at.% Cu, by the method of thermomechanical analysis. Values of the thermal coefficients of linear expansion in solid (αg) and visco-plastic (αω) phase were determined. On the basis of the results obtained using the mentioned methods it was possible to determine the specific temperature of the beginning of the softening process of the glass (T g), as well as the temperature of the beginning of the deformation (T ω). It was shown that coefficients of linear expansion decrease with the increase of Cu content. On the other hand, the increase of Cu content caused the increase of the temperatures. The analytical forms of dependence of four physical parameters αg, αω, T g, T ωas a function of the Cu content were fitted.
Abstract
Results of thermal investigations of the amorphous five-component chalcogenide system Ge20As14(SexS1−x)52I14 are presented. Differential thermal analysis (DTA), derivative differential thermal analysis (DDTA), and dilatometry were employed to determine the temperatures of softening and partial crystallization of the samples. Thermal treatment of the samples at 1000°C and recording of the corresponding thermogravimetric (TG) and derivative thermogravimetric (DTG) curves allowed an elucidation of the full mechanism of their decomposition, which proceeds via seven characteristic phase transitions.
Abstract
Kinetic analysis of the crystallization process in Bi4(As2S3)96 and Bi6(As2S3)94 glasses was performed based on DSC curves recorded under non-isothermal measurement conditions. Samples were thermally treated at different heating rates in the temperature range 300–770 K. The activation energy of crystallization E and the pre-exponential factor K 0 are determined by the Kissinger method and the characteristic crystallization parameters m and n of investigated glasses by the Matusita method. For both crystallization processes the glass with 4 at.% of Bi is characterized by the mechanism of volume nucleation, which is manifested in the form of two-dimensional growth at the first crystallization process, and as three-dimensional at the second one. On the other hand, in the sample with 6 at.% Bi, the average value of the parameter m is close to one, which indicates one-dimensional crystal growth. Compatibility of the values of the parameters m and n suggests that this sample has a large number of crystallization centers, which do not increase significantly during the thermal treatment.
Metal complexes with pyrazole-derived ligands
IV. Thermal decomposition of cobalt(II) complexes with 3(5)-anmo-4-acetyl-5(3)-methylpyrazole
The thermal decomposition of tetrahedral cobalt(II) complexes with 3(5)-amino-4-acetyl5(3)-methylpyrazole (HL) of the general formula [Co(HL)2X2] (X=Cl, Br, I, NCO, NCS) and octahedral [Co(HL)2(H2O)4](NO3)2 and [Co(HL)2−N(CN)2}2] complexes was investigated in air atmosphere in the interval from room temperature to 1000°C. Decomposition of the complexes occurred in several successive endothermic and exothermic processes, and the residue was in all cases CoO.
Abstract
The paper describes results of a study of glasses of the type Cux (AsSe1.4 I0.2 )100–x for x =0, l, 5, 10, 15, 20 and 25 at% Cu, by the methods of thermomechanical analysis. Values of the thermal coefficients of linear expansion in solid and visco-plastic phase were determined and the dependence of this parameter on copper concentration was established. The experimental method used enabled the determination of characteristics glass transition temperature and the temperature of the beginning of deformation, and it was found that these parameters increase with increase in the copper content.
The objective of this paper is to investigate variability in chemical composition, total fatty acid and cholesterol content in m. longissimus dorsi (MLD) of Mangalitsa, swallow-belly (LM) and white (BM), and Swedish Landrace pigs (SL). Compared to SL, the total fat content has been 14.2% higher in BM, while it has been 10.2% higher in LM. SL fatteners contained significantly less cholesterol in MLD compared to LM and BM (−13.6 and −14.8%, P≤0.05). A higher percentage of SFA (+8.5 and +10.1%, P≤0.05) and PUFA (+8.0 and +9.4%, P≤0.05) has been established in MLD, originating from SL fatteners, compared to both Mangalitsa strains. The total MUFA content was higher in LM and BM than in SL (P≤0.05). A phenotypic correlation between protein content and ashes with water content in MLD has been positive (0.81 and 0.88), while the correlation between water content and total fats has been found to be negative (−0.99). A negative phenotypic correlation between MUFA and SFA, as well as PUFA and MUFA (−0.97 and −0.98) has been established, statistically significant at the level of P≤0.001. A positive phenotypic correlation between PUFA and SFA (0.90), statistically significant at the level of P≤0.001, has been found.
