FRACTAL ANALYSIS OF THE NANOSTRUCTURE OF A HETEROGENEOUS HIGH COERCITY ALLOY

Методом атомно-силовой микроскопии получены изображения наноструктры составляющих гетерогенного интерметаллида SmCoCuFeZr в высококоэрцитивном состоянии. На микроуровне в сплавах выделили два типа областей (фазовых составляющих) отличающихся по интегральному элементному составу и интервалам коэрцитивности. На основе данных атомно-силового микроскопа проводится анализ фрактальных характеристик поверхности этих областей. Показано, что фрактальная размерность наноструктуры коррелирует с локальной коэрцитивностью фазовых составляющих. Фазовая составляющая с относительно низкой коэрцитивностью демонстрирует возможность существования структур с фрактальной размерностью в диапазоне 2,396 - 2,475, что соответствует умеренно развитому фрактальному рельефу. При этом высококоэрцитивная составляющая с регулярной наноструктурой характеризуется более высокой фрактальной размерностью 2,452 - 2,508, а на отдельных участках образца встречались области с фрактальной размерностью до 2,577 . The atomic force microscopy was used to obtain images of the nanostructure of components of a heterogeneous intermetallic SmCoCuFeZr compound in a highly coercive state. At the microlevel, two types of regions were distinguished in the alloys, differing in integral elemental composition and coercivity intervals. Based on the atomic force microscopy data, an analysis of the fractal characteristics of the surface is carried out on both of the above types of areas. It is shown that the fractal dimension of the nanostructure correlates with the local coercivity of the phase components. The phase component with a relatively low coercivity demonstrates the possibility of the existence of structures with fractal dimensions in the 2,396 - 2,475 range corresponding to a moderately developed fractal relief. In this case, the high-coercive component with a regular nanostructure is characterized by a higher fractal dimension of 2,452 - 2,508, and in some areas of the sample there were regions with a fractal dimension up to the value of 2,577.

Research on the Preparation Parameters and Basic Properties of Premelted Calcium Aluminate Slag Prepared from Secondary Aluminum Dross

Secondary aluminum dross is a byproduct of the electrolytic aluminum industry, whose main components are Al2O3, AlN and Na3AlF6. Secondary aluminum dross is a type of hazardous waste, with a tremendous yield every year. Realizing the harmless treatment or resource utilization of secondary aluminum dross has important economic and social benefits. In the present research, the process of preparing premelted calcium aluminate slag used for molten steel refining from secondary aluminum dross was studied in detail. Firstly, the chemical composition and phase component of secondary aluminum dross were analyzed systematically. Then, according to phase diagram analysis and melting point measurement, the appropriate mixing ratio of CaO and secondary aluminum dross and the appropriate calcination temperature were determined. On this basis, an experiment of premelted calcium aluminate slag preparation was carried out in a tubular resistance furnace. The phase component and micromorphology of the premelted slag were analyzed by XRD and SEM. The results show that the main component of the premelted calcium aluminate slag is 11CaO·7Al2O3·CaF2 phase with a low melting point. The original Na3AlF6 phase, which is the cause of leachable fluoride in secondary aluminum dross, disappears totally, and there is no water-soluble fluoride detected in the leaching toxicity detection. The research indicates that the process of preparing premelted calcium slag from secondary aluminum dross is feasible, which provides a helpful reference for the resource utilization of secondary aluminum dross.

RESEARCH OF THE MECHANISM OF COMPACTION OF MIXTURES OF POWDERS OF REFRACTORY CARBIDES WITH A METALLIC BOND IN EXPLOSIVE PRESSING ON A METAL SUBSTRATE

The results of investigations of the features of the behavior of the components of mixtures of refractory carbide powders with metals during explosive pressing are presented. It is shown that the main factor determining the compaction of mixtures is the dynamic flow of one of the phase components of the mixture into the initial pores of the powder. As the phase component of the mixture, the movement of which limits the degree of compaction and leads to the formation of a continuous matrix in the structure of the material pressed by the explosion, both the metal binder and the carbide component of the material can act.

Hydrocarbon detection based on Phase decomposition in Chaoshan Depression, northern South China Sea

Located in northern South China Sea, Chaoshan Depression is mainly a residual Mesozoic depression, with a construction of Meso-Cenozoic strata over 7000m thick and good hydrocarbon accumulation conditions. Amplitude attribute of -90°phase component derived by phase decomposition is employed to detect Hydrocarbon in the zone of interest (ZOI) in Chaoshan Depression. And it is found that there are evident amplitude anomalies occurring around ZOI. Phase decomposition is applied to forward modeling results of the ZOI, and high amplitudes occur on the -90°phase component more or less when ZOI is charged with hydrocarbon, which shows that the amplitude abnormality in ZOI is probably caused by oil and gas accumulation.

Anisotropy of out-of-phase magnetic susceptibility due to eddy currents in graphite ore and its structural implications

<p>Magnetostatic susceptibility of single crystals of graphite is negative (the mineral is diamagnetic) and strongly anisotropic. The in-phase component of dynamic susceptibility (measured in alternating magnetic field) is also negative, but an order-of-magnitude stronger than the magnetostatic susceptibility. The out-of-phase component, which is no doubt due to electrical eddy currents, is positive and strong. Consequently, if the graphite crystals in graphite ore are oriented preferentially by crystal lattice (LPO), one would expect strong anisotropy of magnetic susceptibility (AMS) of graphite ore in both in-phase (ipAMS) and out-of-phase (opAMS) components. The ipAMS is controlled not only by the LPO of graphite, but also by the preferred orientation of paramagnetic and ferromagnetic minerals of the barren rock, while the opAMS indicates only the LPO of graphite. In graphite ores occurring in the Moldanubian Unit of Southern Bohemia, the in-phase susceptibility ranges from negative values in the order of 10<sup>-5</sup> [SI units] to positive values in the order of 10<sup>-4</sup>. This probably indicates simultaneous control by graphite and paramagnetic and/or ferromagnetic minerals. On the other hand, the out-of-phase susceptibility is much higher, in the order of 10<sup>-4</sup>, and no doubt indicates its graphite control. The degree of ipAMS is moderate, that of opAMS is truly high. The ipAMS foliation is roughly parallel to the metamorphic foliation in ores and wall rocks and the ipAMS lineation is parallel to the mesoscopic lineation. The opAMS is inverse to the ipAMS with the opAMS lineation being perpendicular to the metamorphic foliation. All this indicates a conspicuous LPO of graphite in the ore that was probably created during Variscan regional metamorphism and associated ductile deformation. The opAMS has therefore shown an effective tool for the investigation of the LPO of graphite in graphite ore or graphite-bearing rocks provided that the opAMS is strong enough to be determined with sufficient precision and graphite is the only conductive mineral in the samples investigated.</p>

Intra Prediction-Based Hologram Phase Component Coding Using Modified Phase Unwrapping

In this paper, we propose a method for compressing the phase component of a full-complex hologram. The JPEG (Joint Photographic Experts Group) Pleno is undergoing standardization for compressing full-complex holograms. If the full-complex hologram is compressed in the form of amplitude and phase components, the three-dimensional information of the hologram may be better preserved. Therefore, in order to solve the disadvantages of the method of independently compressing real and imaginary parts, we propose a method for directly compressing phase information. We select the HEVC (High Efficiency Video Coding), which has the best performance in compressing holograms from previous studies, as the anchor codec, and propose an algorithm for converting the phase information into the form suitable for the HEVC. Since the phase component is very random, we propose a modified phase unwrapping technique to improve this. In addition, in order to make good use of the property of HEVC Intra coding, the phase unwrapping considering Intra prediction is applied, and the most suitable HEVC Intra coding condition is searched. Compared with the result of compressing the phase using the HEVC, the hologram was improved by 2 dB or more and the reconstruction result was improved by more than 4 dB at a compression ratio of 80:1. If the compression ratio is increased, the proposed method has better results.