Vol 19, No 6 (2025)

Multimaterial 3D printing by the substrate-based synthesis (SBS) method is a promising approach to obtain the products with the locally variable properties. However, the processing limits associated with various differences in the physicochemical properties of the materials being combined and the lack of a systematic classification hinder the development of this area. A new classification of multi-materials for SBS has been developed that includes three groups: homogeneous alloys (based on a single metal), dissimilar weldable alloys, and dissimilar non-weldable alloys. The features of transition zones for seven systems (VT6/VT1-0, AlSi10Mg/Al-Si-Mg-Cu, 316L/FeNi36, VZh159/BrKhTsrT V, Ti6Al4V/Inconel 718, 316L/NiTi) have been studied. It has been established that the number of defects, microstructure, and phase composition of the transition zone are determined by the type of alloy combination. The developed classification allows us to systematize the research works, optimize printing parameters, including of the laser tools, and predict any possible problems occurred when developing new multi-material systems.

This paper provides a modification method for the surface layer of mixed tantalum–hafnium carbide samples to obtain the samples with extremely high density required for reliable implementation of the experiments related to the mass spectrometry of vapor generated during the laser-induced evaporation. Such samples were obtained by remelting the surface layer of tantalum–hafnium carbide ceramics using a series of subsecond laser pulses. Analysis of the obtained remelted areas has shown that the crystallized melt area is single-phase mixed carbide, namely a solid solution of the HfC – TaC system that is characterized by a highly uniform distribution of tantalum and hafnium throughout the remelted area. The time-of-flight mass spectrometry was used to study the evolution of vapor components during the laser-induced evaporation process of pre-melted carbide that demonstrated a good correlation with the surface temperature in contrast to the experiments with the sintered ceramics.

The article examines the aluminum contacts on silicon wafers developed by the laser-induced forward transfer. It is determined that a single-pulse regime with an energy density of 15 J/cm² leads to an aluminum concentration of 18.6% and a minimum contact resistance of 439 ± 4 Ohm. The method simplifies the contact generation process and eliminates the need for complex cleaning, making it promising for future silicon-based electronic applications.

Mach-Zehnder microwave modulators on bulk or thin film lithium niobate are key components in data transmission networks, including quantum communications. However, the problem of operating point drift is still significant. A lot of methods for DC bias compensation for different technical tasks have been demonstrated. In this paper, we propose analog electrical scheme for thermal DC bias compensation using a thermistor system. We demonstrate the tuning of the electrical scheme for the operating point bias from temperature, and then experimentally confirm the effectiveness of this method by obtaining the maximum deviation from the mean optical power no more than 1.0 dB or 1.0 V applied DC voltage at temperature up to 45 °C. The proposed approach does not require any additional power supply for adjustment and can be used for special tasks in remote locations.

The efficiency of functioning and neutralization of speech information leakage channels through the fiber-optic utilities is largely determined by the noise pollution of the optical channel in the structured cabling systems of the facility. Adaptation of the well-known noise control methods in the fiber-optic speech information leakage channels allows to significantly increase the signal-to-noise ratio and, consequently, the interception efficiency. In particular, the fiber-optic subsystem of structured cabling systems at the facility with the distributed measuring properties can be represented as a phased acoustic fiber-optic array. While using the integration method for multichannel measurement, an informative signal can be isolated against the noise background. Another noise control method represents the comparison of two optical channels with asymmetric acoustic sensitivity (the differential method) that is possible due to the placement of optic fiber duplex cables in the cable ducts. The differential noise reduction method was tested on an experimental unit for investigating the speech information leakage channel that demonstrated a significant increase in the signal-to-noise ratio even at the short cable lengths. The differential method implementation is possible due to the correlation of low-frequency noise in the optical channel over a long period of time (0.1 ms) and a significant light path in the optical fiber (20 km). The given theoretical and practical studies show a high level of danger of acoustic fiber-optic speech information leakage channels and possible countermeasures.

The luminescent complexes of terbium and europium with tetrafluoroterephthalic acid and phenanthroline were studied for application in thermometry. It was shown that in contrast to a mixture of individual complexes demonstrating various photodegradation rates, the bimetallic complex retains a stable intensity ratio of the Tb³⁺ and Eu³⁺ emission bandswith a general decrease in the luminescence intensity. The composite materials based on the synthesized complexes in polyimide and polystyrene matrices were developed with simultaneous combination of thermosensitive properties with mechanical stability. The results obtained offer opportunities for the development of stable luminescent thermometers for biological and microelectronic applications.