Millimeter-wave band subsurface sounding module

Radio-wave devices are used for many environmental and material research tasks. These devices and the development of relatively simple and affordable quasi-optic radio wave receivers and transmitters of millimeter and terahertz bands are important for numerous applications. Results of the design of a terahertz-band quasioptical transmitter-receiver module are presented. The module is intended for the remote detection of various objects and for measuring the depolarized field components backscattered by various long objects hidden behind obstacles (building materials and/or everyday items that prevent visual contact with the objects). These may be interfaces between materials with different dielectric constants, fiber optic cables, electric cables, and otherobjects. Results of full-scale experimental testing of the module on the detection of electric cables buried under plater in the wall of a building are presented.

Mechanical Stability, Electronic And Magnetic Properties Of Half- Heusler FeCrAs Alloy For Spintronics Application

The search for functional materials in spintronic devices has become a major component of material research in recent times. The structural, elastic, mechanical, electronic and magnetic properties of half-Heusler FeCrAs alloy (HHFCA) have been examined adopting spin-polarized density functional theory calculations. Our result shows that the hexagonal structure is the high pressure phase of the FeCrAs alloy while the half-Heusler structure is the more stable phase at ambient pressure. Also, the HHFCA is mechanically stable and exhibits half-metallic ferromagnetism besides an indirect band gap in the minority spin channel. The total magnetic moment in one formula unit of the alloy is 1.00 μB, in agreement with the Slater-Pauling rule and the bulk of the magnetic moment contributed by the Cr atoms. Furthermore, high Curie temperature of ~ 1000 K has been obtained for the HHFCA which suggests that it is a promising material for spintronic applications.

Electrospun Methacrylated Gelatin/Poly(L-Lactic Acid) Nanofibrous Hydrogel Scaffolds for Potential Wound Dressing Application

Electrospun nanofiber mats have attracted intense attention as advanced wound dressing materials. The objective of this study was to fabricate methacrylated gelatin (MeGel)/poly(L-lactic acid) (PLLA) hybrid nanofiber mats with an extracellular matrix (ECM) mimicking nanofibrous structure and hydrogel-like properties for potential use as wound dressing materials. MeGel was first synthesized via the methacryloyl substitution of gelatin (Gel), a series of MeGel and PLLA blends with various mass ratios were electrospun into nanofiber mats, and a UV crosslinking process was subsequently utilized to stabilize the MeGel components in the nanofibers. All the as-crosslinked nanofiber mats exhibited smooth and bead-free fiber morphologies. The MeGel-containing and crosslinked nanofiber mats presented significantly improved hydrophilic properties (water contact angle = 0°; 100% wettability) compared to the pure PLLA nanofiber mats (~127°). The swelling ratio of crosslinked nanofiber mats notably increased with the increase of MeGel (143.6 ± 7.4% for PLLA mats vs. 875.0 ± 17.1% for crosslinked 1:1 MeGel/PLLA mats vs. 1135.2 ± 16.0% for crosslinked MeGel mats). The UV crosslinking process was demonstrated to significantly improve the structural stability and mechanical properties of MeGel/PLLA nanofiber mats. The Young’s modulus and ultimate strength of the crosslinked nanofiber mats were demonstrated to obviously decrease when more MeGel was introduced in both dry and wet conditions. The biological tests showed that all the crosslinked nanofiber mats presented great biocompatibility, but the crosslinked nanofiber mats with more MeGel were able to notably promote the attachment, growth, and proliferation of human dermal fibroblasts. Overall, this study demonstrates that our MeGel/PLLA blend nanofiber mats are attractive candidates for wound dressing material research and application.

Stretchable Systems

Stretchable electronics is one of the transformative pillars of future flexible electronics. As a result, the research on new passive and active materials, novel designs, and engineering approaches has attracted significant interest. Recent studies have highlighted the importance of new approaches that enable the integration of high-performance materials, including, organic and inorganic compounds, carbon-based and layered materials, and composites to serve as conductors, semiconductors or insulators, with the ability to accommodate electronics on stretchable substrates. This Element presents a discussion about the strategies that have been developed for obtaining stretchable systems, with a focus on various stretchable geometries to achieve strain invariant electrical response, and summarises the recent advances in terms of material research, various integration techniques of high-performance electronics. In addition, some of the applications, challenges and opportunities associated with the development of stretchable electronics are discussed.

Multi-walled carbon nanotubes (MWCNTs)-reinforced ceramic nanocomposites for aerospace applications: a review

Advances in the nanotechnology have been actively applied to the field of aerospace engineering where there is a constant necessity of high durable material with low density and better thermo-mechanical properties. Over the past decade, carbon nanotubes-based composites are widely utilised owing to its fascinating properties resulting in series of multidisciplinary industrial applications. Carbon nanotubes (CNTs) are rolled up sheets of carbon in nanoscale which offers excellent thermal and mechanical properties at lower density which makes them suitable reinforcement for composites in aerospace applications. Owing to its high Young’s modulus and chemically inert behaviour, CNTs are forefront of material research with applications varying from water purification to aerospace applications where applicational sector remains a mystery. Although there has been numerous research on the CNTs-based materials, there are only limited studies focusing on its utilisation for the field of aerospace engineering. As a result, in this review, we intend to cover the processing and synthesis techniques, thermal and mechanical properties as well as few industrial applications of CNTs-reinforced ceramic composites. Further, any potential development in additive manufacturing-based technique for fabricating CNT/ceramics and its applications in aerospace industries have been highlighted.

Storytelling in Instagram: Exploring a Creative Learning in Digital Era

Teaching and learning in the 21st century require students to become active thinkers in using technology to learn, innovate, communicate, and discover new knowledge. Instagram media was a great tool to showcase learning in an innovative learning environment where students took ownership of their learning and ideas. It could be used as hands-on training and build local and professional communities' knowledge. The sample for this study was 15 students from Tritech Informatika High School located in North Sumatra, Indonesia. Data was collected through interviews and related literature. Data analysis was analyzed using open coding methods that examined classified, tabulated, or combined evidence to solve the original research problem. Qualitative analysis that was conducted showed that Instagram media was the most used social media platform among participants, preferring to use it for educational and language learning purposes. This showed that social learning positively affected learning material research, motivation, academic and academic achievement satisfaction, and cooperative learning.

Research Progress on Corrosion of Equipment and Materials in Deep-Sea Environment

The deep sea is the frontier of materials research in the 21st century. Owing to the particularity of pressure (15–120 MPa), hydrothermal temperature (90–400°C), and explosive fluid (strong H2S) in the deep-sea hydrothermal field environment, the research on the corrosion mechanism of service materials in this environment under the coupling action of many harsh factors is almost blank. It has become the bottleneck of equipment and material research and development for China to explore the deep sea. This paper reviews the research progress of corrosion mechanisms of deep-sea environmental materials at home and abroad, and forecasts the research trend and difficulties in this field, especially in the deep-sea hydrothermal field. At the same time, it points out the urgency of the construction of harsh environment materials platform and its relevance to the discipline construction of marine college.

6 nm super-resolution optical transmission and scattering spectroscopic imaging of carbon nanotubes using a nanometer-scale white light source

Optical transmission and scattering spectroscopic microscopy at the visible and adjacent wavelengths denote one of the most informative and inclusive characterization methods in material research. Unfortunately, restricted by the diffraction limit of light, it cannot resolve the nanoscale variation in light absorption and scattering, diagnostics of the local inhomogeneity in material structure and properties. Moreover, a large quantity of nanomaterials has anisotropic optical properties that are appealing yet hard to characterize through conventional optical methods. There is an increasing demand to extend the optical hyperspectral imaging into the nanometer length scale. In this work, we report a super-resolution hyperspectral imaging technique that uses a nanoscale white light source generated by superfocusing the light from a tungsten-halogen lamp to simultaneously obtain optical transmission and scattering spectroscopic images. A 6-nm spatial resolution in the visible to near-infrared wavelength regime (415–980 nm) is demonstrated on an individual single-walled carbon nanotube (SW-CNT). Both the longitudinal and transverse optical electronic transitions are measured, and the SW-CNT chiral indices can be identified. The band structure modulation in a SW-CNT through strain engineering is mapped.

Hybrid van der Waals heterojunction based on two-dimensional materials

Since the discovery of graphene, two-dimensional (2D) layered materials have always been the focus of material research. The layers of 2D materials are covalent bonds, and the layers are weakly bonded to adjacent layers through van der Waals (vdW) interactions. Since any dangling-bond-free surface could be combined with another material through vdW forces, the concept can be extended. This can refer to the integration of 2D materials with any other non-2D materials through non-covalent interactions. The emerging mixed-dimensional (2D+nD, where n is 0, 1 or 3) heterostructure devices has been studied and represents a wider range of vdW heterostructures. New electronic devices and optoelectronic devices based on such heterojunctions have unique functions. Therefore, this article depicts the research progress of (2D+nD, where n is 0, 1 or 3) vdW heterojunctions based on 2D materials.