In this work, the growth mechanisms of Si1-xGex and (Si2)1-x(GaP)x solid mixture crystals, based on Si, Ge, and GaP nanoclusters, are considered, and quantum-chemical calculations are performed. Quantum chemical calculations determine the stable isomers of nanoclusters and their corresponding theoretical total energies, Gibbs free energies, and entropy changes. This study investigates the composition of the crystals and concludes that Ge is most likely present in the atomic and Ge2 states in the silicon crystal lattice, in the Si5 and Si20 states in the Ge crystal lattice, and in the Si2 state in the GaP crystal lattice. Energy-dispersive X-ray and ATR-FTIR spectroscopy confirm the chemical composition and bonding of the experimentally obtained crystals.
Growth of 200 mm float-zone (FZ) silicon single crystals is susceptible to thermal stress, which can promote dislocation generation and crystal cracking. A steady-state global finite-element model was established in CGSim to evaluate the thermal field and thermoelastic stress in an industrial 200 mm FZ silicon growth system. Quartz, graphite, molybdenum, and silicon carbide thermal shields were compared, followed by an assessment of molybdenum-shield lengths of 10, 20, and 30 cm. The numerical results show that the molybdenum shield reduces the crystal-edge temperature gradient and von Mises stress through coupled conductive and radiative heat-transfer effects. The 30 cm molybdenum shield was the best-performing configuration among the investigated lengths. Industrial verification comprised 60 crystals, with 15 crystals in each configuration. For the normal thermal field, the dislocation and cracking rates were 13.3% (2/15) and 20.0% (3/15), respectively. The corresponding rates were 6.6% (1/15) and 6.6% (1/15) for the 10 cm shield, 13.3% (2/15) and 0% (0/15) for the 20 cm shield, and 0% (0/15) and 0% (0/15) for the 30 cm shield. The intermediate groups did not exhibit a strictly monotonic response for every defect indicator, whereas the 30 cm configuration provided the best overall industrial outcome under the investigated conditions.
Synthesis, characterization, and image processing of a new series of N (p-n-Nonyloxy benzylidene) p-n- Alkyl Aniline (9O.m; m = 4,7,9) compounds by varying the alkyl chain length have been reported. The objective was to identify the liquid crystalline phases and compare the device parameters of these compounds with respect to the increase in alkyl chain length. The characterization of these compounds was performed by UV spectroscopy, Fourier-Transform Infrared (FT-IR) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. The phase behavior was explored using Polarized Optical Microscopy (POM) and Differential Scanning Calorimetry (DSC). The smectic textures observed at various temperatures were analyzed and compared. The transition temperatures, thermal stability factor, order of phase transition have been reported. Furthermore, image processing studies were performed using MATLAB software. The reported image descriptors are helpful in device manufacturing for accurate texture analysis and real-time quality control during display device production. Based on various characterizations and parameters, a superior molecule was concluded for the device architecture.
The densification behavior and mechanical properties of B4C-based composite ceramics were tailored by introducing Y2O3-Nd2O3 rare earth oxide additives during spark plasma sintering. The effects of additive content and sintering temperature on phase evolution, microstructure, and mechanical performance were systematically investigated. The additives promoted liquid phase formation and significantly enhanced densification. High temperature reactions between B4C and the oxides produced secondary phases including (YNd)B6, (YNd)B4, (YNd)3C4, (YNd)BO3, and B2O3, with (YNd)B6 forming preferentially. Increasing the additive content and sintering temperature led to a rise, followed by a decline, in relative density, hardness, flexural strength, and fracture toughness. At 1800 degrees C, the composites achieved a flexural strength of 337 MPa and a fracture toughness of 2.73 MPa center dot m1/2. These results demonstrate an effective approach for controlling phase formation and improving the mechanical performance of B4C-based composite ceramics.
In the present study, vanadium doped BaO-Li2O-Bi2O3-WO3-B2O3 glasses were synthesized using the conventional melt-quenching technique. The amorphous nature of the prepared samples was confirmed through X-ray Diffraction (XRD), ensuring the formation of a homogeneous glass network suitable for optical investigations. To understand the role of vanadium ions in modifying the optical behavior of the host matrix, detailed UV-visible absorption studies were carried out. The spectra indicate systematic changes in the optical absorption edge, suggesting that the optical band gap energy (Eopt) and metallization criterion (M) increase with the incorporation of V2O5. Such behaviour is characteristic of enhanced electronic localization, implying that these glasses exhibit semiconducting features in their amorphous state. In addition, a comprehensive set of optical parameters such as refractive index (n), absorption coefficient (alpha), extinction coefficient (K), optical conductivity (sigma op), optical polarizability (alpha o), theoretical optical basicity (Lambda th) and other optical parameters were calculated across the studied wavelength range. These parameters explore the details on electronic transitions and polarizability effect imparted by the vanadium ions. This study ensures the prospect of using transition-metal-doped boro-bismuthate glasses in photonic components, nonlinear optical devices, and other emerging optoelectronic applications.
