Hasil untuk "Materials Science"

Junchen Li, Qiushuang Wang, Swee Leong Sing et al.

Conventional manufacturing of 430 ferritic stainless steel faces significant challenges, including severe work hardening, rapid tool wear, and limited strengthening via heat treatment. To overcome these limitations, this study employs laser powder bed fusion (LPBF) technology to fabricate high-density (99.93%) 430 stainless steel samples through systematic process parameter optimisation. The as-built samples exhibit a unique microstructure characterised by columnar ferrite grains with a <100 >  fibre texture along the building direction and a few oxides enriched in aluminium, oxygen, and nitrogen. In terms of mechanical properties, the as-built sample exhibits high yield strength of approximately 747.5 MPa, nearly double that of the conventionally hot rolled counterpart, while maintaining considerable ductility (∼29.2%). This significant strengthening is primarily attributed to the high-density dislocations generated during the LPBF forming process. This work demonstrates the potential of LPBF for producing high-performance ferritic stainless steels with enhanced mechanical properties.

B.V. Nikolaev, N.A. Pavlova

Background. Domestic diplomacy and international legal science played a leading role in the formation of the institution of peaceful resolution of international disputes. It was Russia that initiated two Hague Peace Conferences in 1899 and 1907. However, this issue has not received sufficient attention from domestic and foreign researchers, the latter, however, actively studied the role of the United States, Great Britain, France and other countries in terms of the development of the institution of peaceful resolution of international disputes. In this regard, the study of the content and results of the Second Peace Conference and its historical significance seems relevant and scientifically significant. The purpose of the work is to identify the main directions and achievements of the Hague Peace Conference of 1907 in the context of the development of the institution of peaceful resolution of international disputes. Materials and methods. These objectives are achieved by analyzing the official materials of the 1907 Hague Peace Conference, official acts of the Russian Ministry of Foreign Affairs, assessments of the conference's achievements given by its participants themselves, as well as international treaties and scientific literature. Results. The work analyzes the work and results of the 1907 forum from the point of view of the development of the institution of peaceful resolution of international disputes. Conclu-sions. The study allows us to draw a conclusion about the special role of Russian diplomacy and international legal science in the codification of the institution of peaceful resolution of international disputes and the progressive development of international law in general.

Bhal Chandra Joshi, Aris Karastergiou, Marta Burgay et al.

The large instantaneous sensitivity, a wide frequency coverage and flexible observation modes with large number of beams in the sky are the main features of the SKA observatory's two telescopes, the SKA-Low and the SKA-Mid, which are located on two different continents. Owing to these capabilities, the SKAO telescopes are going to be a game-changer for radio astronomy in general and pulsar astronomy in particular. The eleven articles in this special issue on pulsar science with the SKA Observatory describe its impact on different areas of pulsar science. In this lead article, a brief description of the two telescopes highlighting the relevant features for pulsar science is presented followed by an overview of each accompanying article, exploring the inter-relationship between different pulsar science use cases.

A. Camposeo, T. Virgili, F. Lombardi et al.

In the context of quantum thermodynamics, quantum batteries have emerged as promising devices for energy storage and manipulation. Over the past decade, substantial progress has been made in understanding the fundamental properties of quantum batteries, with several experimental implementations showing great promise. This Perspective provides an overview of the solid-state materials platforms that could lead to fully operational quantum batteries. After briefly introducing the basic features of quantum batteries, we discuss organic microcavities, where superextensive charging has already been demonstrated experimentally. We then explore other materials, including inorganic nanostructures (such as quantum wells and dots), perovskite systems, and (normal and high-temperature) superconductors. Key achievements in these areas, relevant to the experimental realization of quantum batteries, are highlighted. We also address challenges and future research directions. Despite their enormous potential for energy storage devices, research into advanced materials for quantum batteries is still in its infancy. This paper aims to stimulate interdisciplinarity and convergence among different materials science research communities to accelerate the development of new materials and device architectures for quantum batteries.

Yusheng Hou, Ruqian Wu

Two-dimensional (2D) magnetism in atomically thin van der Waals (vdW) monolayers and heterostructures has attracted significant attention due to its promising potential for next-generation spintronic and quantum technologies. A key factor in stabilizing long-range magnetic order in these systems is magnetic anisotropy, which plays a crucial role in overcoming the limitations imposed by the Mermin-Wagner theorem. This review provides a comprehensive theoretical and experimental overview of the importance of magnetic anisotropy in enabling intrinsic 2D magnetism and shaping the electronic, magnetic, and topological properties of 2D vdW materials. We begin by summarizing the fundamental mechanisms that determine magnetic anisotropy, emphasizing the contributions from strong ligand spin-orbit coupling of ligand atoms and unquenched orbital magnetic moments. We then examine a range of material engineering approaches, including alloying, doping, electrostatic gating, strain, and pressure, that have been employed to effectively tune magnetic anisotropy in these materials. Finally, we discuss open challenges and promising future directions in this rapidly advancing field. By presenting a broad perspective on the role of magnetic anisotropy in 2D magnetism, this review aims to stimulate ongoing efforts and new ideas toward the realization of robust, room-temperature applications based on 2D vdW magnetic materials and their heterostructures.

Wentao Li, Yizhe Chen, Jiangjie Qiu et al.

Data scarcity and the high cost of annotation have long been persistent challenges in the field of materials science. Inspired by its potential in other fields like computer vision, we propose the MatWheel framework, which train the material property prediction model using the synthetic data generated by the conditional generative model. We explore two scenarios: fully-supervised and semi-supervised learning. Using CGCNN for property prediction and Con-CDVAE as the conditional generative model, experiments on two data-scarce material property datasets from Matminer database are conducted. Results show that synthetic data has potential in extreme data-scarce scenarios, achieving performance close to or exceeding that of real samples in all two tasks. We also find that pseudo-labels have little impact on generated data quality. Future work will integrate advanced models and optimize generation conditions to boost the effectiveness of the materials data flywheel.

Luca Foppiano, Guillaume Lambard, Toshiyuki Amagasa et al.

This study is dedicated to assessing the capabilities of large language models (LLMs) such as GPT-3.5-Turbo, GPT-4, and GPT-4-Turbo in extracting structured information from scientific documents in materials science. To this end, we primarily focus on two critical tasks of information extraction: (i) a named entity recognition (NER) of studied materials and physical properties and (ii) a relation extraction (RE) between these entities. Due to the evident lack of datasets within Materials Informatics (MI), we evaluated using SuperMat, based on superconductor research, and MeasEval, a generic measurement evaluation corpus. The performance of LLMs in executing these tasks is benchmarked against traditional models based on the BERT architecture and rule-based approaches (baseline). We introduce a novel methodology for the comparative analysis of intricate material expressions, emphasising the standardisation of chemical formulas to tackle the complexities inherent in materials science information assessment. For NER, LLMs fail to outperform the baseline with zero-shot prompting and exhibit only limited improvement with few-shot prompting. However, a GPT-3.5-Turbo fine-tuned with the appropriate strategy for RE outperforms all models, including the baseline. Without any fine-tuning, GPT-4 and GPT-4-Turbo display remarkable reasoning and relationship extraction capabilities after being provided with merely a couple of examples, surpassing the baseline. Overall, the results suggest that although LLMs demonstrate relevant reasoning skills in connecting concepts, specialised models are currently a better choice for tasks requiring extracting complex domain-specific entities like materials. These insights provide initial guidance applicable to other materials science sub-domains in future work.

Wei Zhou, Guilin Zeng, Haotian Jin et al.

In terms of new-generation energy-storing devices, aqueous zinc-ion batteries (AZIBs) are becoming the prime candidates because of their inexpensive nature, inherent safety, environmental benignity and abundant resources. Nevertheless, due to a restrained selection of cathodes, AZIBs often perform unsatisfactorily under long-life cycling and high-rate conditions. Consequently, we propose a facile evaporation-induced self-assembly technique for preparing V₂O₃@carbonized dictyophora (V₂O₃@CD) composites, utilizing economical and easily available biomass dictyophora as carbon sources and NH₄VO₃ as metal sources. When assembled in AZIBs, the V₂O₃@CD exhibits a high initial discharge capacity of 281.9 mAh g⁻¹ at 50 mA g⁻¹. The discharge capacity is still up to 151.9 mAh g⁻¹ after 1000 cycles at 1 A g⁻¹, showing excellent long-cycle durability. The extraordinary high electrochemical effectiveness of V₂O₃@CD could be mainly attributed to the formation of porous carbonized dictyophora frame. The formed porous carbon skeleton can ensure efficient electron transport and prevent V₂O₃ from losing electrical contact due to volume changes caused by Zn²⁺ intercalation/deintercalation. The strategy of metal-oxide-filled carbonized biomass material may provide insights into developing high-performance AZIBs and other potential energy storage devices, with a wide application range.

Huaiyuan Liu, Donglin Ma, Yantao Li et al.

When depositing films on a complex workpiece surface by magnetron sputtering, the shadow effect occurs and causes the columnar structure to tilt toward the substrate owing to the oblique incident angle of the plasma flux, affecting the microstructure and properties of the films. Improving the surface diffusion could alleviate the shadow effect, whereas changing the energy of the deposited particles could improve surface diffusion. Different substrate conductivities could affect the energy of the deposited particles when they reach the substrate. In this study, Si (semiconductor) and SiO₂ (insulator) sheets are mounted on the inner surface of a hemispherical workpiece, and Ti films with different thicknesses (adjusted by the deposition time) are deposited on the inner surface of the hemispherical workpiece by direct current magnetron sputtering. The results show that there is a threshold thickness and incident angle before the films are affected by the shadow effect. The threshold could be affected by the film thickness, the incident angle, and the conductivity of the substrate. The threshold would decrease as the film thickness or incidence angle increased or the conductivity of the substrate decreased. When the film thickness or incident angle does not reach the threshold, the film would not be affected by the shadow effect. In addition, the film deposited later would tilt the vertical columnar structure of the film deposited earlier. Owing to the different conductivities, the shadow effect manifest earlier for Ti films deposited on the insulator SiO₂ than for films deposited on the semiconductor Si when the film thickness is >500 nm.

GREX-PLUS Science Team, :, Akio K. Inoue et al.

GREX-PLUS (Galaxy Reionization EXplorer and PLanetary Universe Spectrometer) is a mission candidate for a JAXA's strategic L-class mission to be launched in the 2030s. Its primary sciences are two-fold: galaxy formation and evolution and planetary system formation and evolution. The GREX-PLUS spacecraft will carry a 1.2 m primary mirror aperture telescope cooled down to 50 K. The two science instruments will be onboard: a wide-field camera in the 2-8 $μ$m wavelength band and a high resolution spectrometer with a wavelength resolution of 30,000 in the 10-18 $μ$m band. The GREX-PLUS wide-field camera aims to detect the first generation of galaxies at redshift $z>15$. The GREX-PLUS high resolution spectrometer aims to identify the location of the water ``snow line'' in proto-planetary disks. Both instruments will provide unique data sets for a broad range of scientific topics including galaxy mass assembly, origin of supermassive blackholes, infrared background radiation, molecular spectroscopy in the interstellar medium, transit spectroscopy for exoplanet atmosphere, planetary atmosphere in the Solar system, and so on.

Mehrdad Jalali, Matthias Mail, Rossella Aversa et al.

This paper introduces a new ontology for Materials Science Laboratory Equipment, termed MSLE. A fundamental issue with materials science laboratory (hereafter lab) equipment in the real world is that scientists work with various types of equipment with multiple specifications. For example, there are many electron microscopes with different parameters in chemical and physical labs. A critical development to unify the description is to build an equipment domain ontology as basic semantic knowledge and to guide the user to work with the equipment appropriately. Here, we propose to develop a consistent ontology for equipment, the MSLE ontology. In the MSLE, two main existing ontologies, the Semantic Sensor Network (SSN) and the Material Vocabulary (MatVoc), have been integrated into the MSLE core to build a coherent ontology. Since various acronyms and terms have been used for equipment, this paper proposes an approach to use a Simple Knowledge Organization System (SKOS) to represent the hierarchical structure of equipment terms. Equipment terms were collected in various languages and abbreviations and coded into the MSLE using the SKOS model. The ontology development was conducted in close collaboration with domain experts and focused on the large-scale devices for materials characterization available in our research group. Competency questions are expected to be addressed through the MSLE ontology. Constraints are modeled in the Shapes Query Language (SHACL); a prototype is shown and validated to show the value of the modeling constraints.

Muhammad Zubair Khan, Oleg E. Peil, Apoorva Sharma et al.

In the rapidly expanding field of two-dimensional materials, magnetic monolayers show great promise for the future applications in nanoelectronics, data storage, and sensing. The research in intrinsically magnetic two-dimensional materials mainly focuses on synthetic iodide and telluride based compounds, which inherently suffer from the lack of ambient stability. So far, naturally occurring layered magnetic materials have been vastly overlooked. These minerals offer a unique opportunity to explore air-stable complex layered systems with high concentration of local moment bearing ions. We demonstrate magnetic ordering in iron-rich two-dimensional phyllosilicates, focusing on mineral species of minnesotaite, annite, and biotite. These are naturally occurring van der Waals magnetic materials which integrate local moment baring ions of iron via magnesium/aluminium substitution in their octahedral sites. Due to self-inherent capping by silicate/aluminate tetrahedral groups, ultra-thin layers are air-stable. Chemical characterization, quantitative elemental analysis, and iron oxidation states were determined via Raman spectroscopy, wavelength disperse X-ray spectroscopy, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy. Superconducting quantum interference device magnetometry measurements were performed to examine the magnetic ordering. These layered materials exhibit paramagnetic or superparamagnetic characteristics at room temperature. At low temperature ferrimagnetic or antiferromagnetic ordering occurs, with the critical ordering temperature of 38.7 K for minnesotaite, 36.1 K for annite, and 4.9 K for biotite. In-field magnetic force microscopy on iron bearing phyllosilicates confirmed the paramagnetic response at room temperature, present down to monolayers.

Yanna Chen, Osami Sakata, Hiroyuki Morita et al.

Romică CREȚU, Liviu Cătălin ȘOLEA

Due to their excellent characteristics, vegetable oils are successfully used in various formulations of organic lubricants. In this context, the advanced biodegradability and excellent lubricity performance of rice oil leads to its being considered as a real potential for the lubricants industry. However, as with other vegetable oils, the stability of rice bran oil is strongly influenced by the oxidation process. Therefore, the aim of this work was the oxidation stability monitorization of rice bran oil by spectrophotometric techniques. For this purpose, oxidation tests of rice bran oil at elevated temperatures were performed. In this paper, transmittance spectra were determined, and the trichromatic components and coordinates were calculated, as well as the colour differences for rice oils subjected to a forced oxidation treatment at temperatures of 100 °C and 120 °C for 4, 8 and 10 hours. The results obtained show that, although after the first 4 hours of forced oxidation significant changes appear on the physicochemical properties of rice bran oil, an increase in the test time from 8 to 10 hours does not lead to significant changes in the analysed parameters, the conclusion being valid for both test temperatures.

Xiao Yan, Jianhua Guo, Xinghua Jiang

Abstract Recently, the application and development of flexible microwave-absorption composites based on silicone rubber have gradually become a research hot spot. In this study, methyl vinyl phenyl silicone rubber (MPVQ)/carbonyl iron particles (CIPs)/graphene (GR) composites were prepared by mechanical blending, and the effects of thermal-ageing temperature on the microwave-absorption properties of the composites were investigated. The mechanism of the thermal-ageing temperature’s effects on microwave-absorption behaviour was identified. The results show that unaged composites have superior microwave-absorption properties, with a minimum reflection loss (RL min ) of − 87.73 dB, a lowest thickness of 1.46 mm, and an effective absorption bandwidth (EAB, RL < − 10 dB) reaching 5.8 GHz (9.9–15.7 GHz). With ageing at 240 °C for 24 h, the RL min at a frequency of 5.48 GHz is − 45.55 dB with a thickness of 2.55 mm, and the EAB value reaches 2 GHz (range 4.6–6.6 GHz). In the thermal-ageing process, a crosslinking reaction occurs in MPVQ with an increase in crosslinking density from 5.88 × 10−5 mol g−1 (unaged) to 4.69 × 10−4 mol g−1 (aged at 240 °C). Simultaneously, thermal degradation of the composites leads to a reduction in the rubber concentration. In addition, a small amount of CIPs are oxidized to Fe3O4, and the remaining CIPs aggregate to generate more electrically conductive pathways. Consequently, the dielectric loss of the composites will be significantly improved, resulting in poor impedance matching. The microwave-absorption properties of the composites gradually decrease with increasing thermal-ageing temperature from 200 to 240 °C.

Yen-Ting Chang, Ming-Hao Lee, Ming-Wen Chu et al.

The microstructures and phase formations of Ti20Zr15Hf15Ni35Cu15 high entropy shape memory alloy (HESMA) under different aging conditions were investigated in this study. At aging temperatures below 500 °C, a large amount of the H-phase formed, and the martensitic transformation temperatures were suppressed due to the strain field around the H-phase. Aging treatment at 600 °C caused a eutectoid reaction, which yielded a lamellar structure composed of (Zr,Hf)7Cu10 and Ti2Cu phases. When the aging treatment was increased to 700 °C, the lamellar structure was no longer observed, but (Zr,Hf)7Cu10 and newly-formed Ti2Ni phases formed around the original Ti2Ni phase. Experimental results demonstrated that the H-phase precipitation, eutectoid decomposition, and (Zr,Hf)7Cu10 formation occurred at different aging temperatures. These results could be utilized to adjust the martensitic transformation temperatures and design microstructures, providing a new strategy for developing TiZrHfNiCu HESMAs.

Wonbae Bang, M. T. Kaffash, M. T. Hossain et al.

We report experimental and theoretical studies of spin dynamics in lattice structures of permalloy (Ni80Fe20) nano-ellipses, with four different types of networks including honeycomb and square lattices. The lattices are patterned at the center line of the co-planar wave guide and consist of non-contacting or contacting ellipses. Micromagnetic simulations show excellent agreement with the broadband ferromagnetic resonance (FMR) experimental results. We find the existence of a spin-wave mode localized in the vertex region of the contacting nano-ellipse network. Our finding has important implications when designing an artificial spin ice (ASI) network for functional magnonics.

Martino Romaniello, the ESO Science Archive operations, development team

The ESO Science Archive is the collection and access point of the data generated at ESO's La Silla Paranal Observatory, both raw and processed. It is a major contributor to ESO's science output, being used in about 4 out of 10 refereed articles with ESO data. In this paper, which is presented on behalf of the operations and development teams, we review its contents, policies, us interfaces and impact.

Fateme Hassanli, Mohammad Hossein Paydar

In the present work, effect of structural design on the mechanical properties of aluminum foams was studied. Aluminum foams with a relative density in the range of 0.28–0.48 with uniform and graded pore frequency were fabricated through powder metallurgy route by using carbamides as space holder, where double action die pressing process was used for producing green compacts. Carbamide space holders were removed by leaching in water plus heating processes, whereafter the samples were sintered at 640 °C for 2 h in air. Mechanical properties and energy absorption capability of the fabricated foam samples were evaluated by the means of compression test. The results showed that correct modification in pore distribution can significantly improve mechanical properties of the fabricated foam by compensating the undesirable density gradient created in the foam structure due to the die wall friction. So that for the foams with a relative density of 0.28, introducing desired gradation in pore frequency caused nearly 100% increase in plateau stress and more than 75% improvement in energy absorption ability of the fabricated foam.

Michael Doube

Sequential region labelling, also known as connected components labelling, is a standard image segmentation problem that joins contiguous foreground pixels into blobs. Despite its long development history and widespread use across diverse domains such as bone biology, materials science and geology, connected components labelling can still form a bottleneck in image processing pipelines. Here, I describe a multithreaded implementation of classical two-pass sequential region labelling and introduce an efficient collision resolution step, ‘bucket fountain’. Code was validated on test images and against commercial software (Avizo). It was performance tested on images from 2 MB (161 particles) to 6.5 GB (437 508 particles) to determine whether theoretical linear scaling (O(n)) had been achieved, and on 1–40 CPU threads to measure speed improvements due to multithreading. The new implementation achieves linear scaling (b = 0.905–1.052, time ∝ pixelsb; R2 = 0.985–0.996), which improves with increasing thread number up to 8–16 threads, suggesting that it is memory bandwidth limited. This new implementation of sequential region labelling reduces the time required from hours to a few tens of seconds for images of several GB, and is limited only by hardware scale. It is available open source and free of charge in BoneJ.