scholarly journals High-entropy ceramics: Present status, challenges, and a look forward

2021 ◽  
Author(s):  
Huimin Xiang ◽  
Yan Xing ◽  
Fu-zhi Dai ◽  
Hongjie Wang ◽  
Lei Su ◽  
...  
Keyword(s):  
Inorganic Compounds ◽  
Rapid Development ◽  
Material Design ◽  
Future Directions ◽  
High Entropy ◽  
New Family ◽  
New Material ◽  
Novel Processing ◽  
Structure Engineering ◽  
Infant Stage

AbstractHigh-entropy ceramics (HECs) are solid solutions of inorganic compounds with one or more Wyckoff sites shared by equal or near-equal atomic ratios of multi-principal elements. Although in the infant stage, the emerging of this new family of materials has brought new opportunities for material design and property tailoring. Distinct from metals, the diversity in crystal structure and electronic structure of ceramics provides huge space for properties tuning through band structure engineering and phonon engineering. Aside from strengthening, hardening, and low thermal conductivity that have already been found in high-entropy alloys, new properties like colossal dielectric constant, super ionic conductivity, severe anisotropic thermal expansion coefficient, strong electromagnetic wave absorption, etc., have been discovered in HECs. As a response to the rapid development in this nascent field, this article gives a comprehensive review on the structure features, theoretical methods for stability and property prediction, processing routes, novel properties, and prospective applications of HECs. The challenges on processing, characterization, and property predictions are also emphasized. Finally, future directions for new material exploration, novel processing, fundamental understanding, in-depth characterization, and database assessments are given.

On the Affinities of the Cretaceous Lamellibranch Genera Trigonioides and Hoffetrigonia

1955 ◽  
Vol 92 (4) ◽  
pp. 345-349 ◽  
Author(s):  
L. R. Cox
Keyword(s):  
East Asian ◽  
New Family ◽  
New Material

AbstractThe East Asian Cretaceous lamellibranch genera Trigonioides and Hoffetrigonia are discussed after examining new material of the former, and the conclusion is reached that both belong to the Unionidae and not to the Trigoniidae. A proposal to include them in a new family is withdrawn.

scholarly journals Cutting Edge of High-Entropy Alloy Superconductors from the Perspective of Materials Research

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1078
Author(s):  
Jiro Kitagawa ◽  
Shusuke Hamamoto ◽  
Naoki Ishizu
Keyword(s):  
Material Design ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
Simple Material ◽  
Σ Phase ◽  
High Entropy ◽  
Cscl Type ◽  
Materials Research ◽  
Face Centered ◽  
New Phenomena

High-entropy alloys (HEAs) are a new class of materials which are being energetically studied around the world. HEAs are characterized by a multicomponent alloy in which five or more elements randomly occupy a crystallographic site. The conventional HEA concept has developed into simple crystal structures such as face-centered-cubic (fcc), body-centered-cubic (bcc) and hexagonal-closed packing (hcp) structures. The highly atomic-disordered state produces many superior mechanical or thermal properties. Superconductivity has been one of the topics of focus in the field of HEAs since the discovery of the bcc HEA superconductor in 2014. A characteristic of superconductivity is robustness against atomic disorder or extremely high pressure. The materials research on HEA superconductors has just begun, and there are open possibilities for unexpectedly finding new phenomena. The present review updates the research status of HEA superconductors. We survey bcc and hcp HEA superconductors and discuss the simple material design. The concept of HEA is extended to materials possessing multiple crystallographic sites; thus, we also introduce multisite HEA superconductors with the CsCl-type, α-Mn-type, A15, NaCl-type, σ-phase and layered structures and discuss the materials research on multisite HEA superconductors. Finally, we present the new perspectives of eutectic HEA superconductors and gum metal HEA superconductors.

Silicon Carbide Radiation Detectors: Progress, Limitations and Future Directions

2013 ◽  
Vol 1576 ◽  
Author(s):  
Frank H. Ruddy
Keyword(s):  
Silicon Carbide ◽  
Rapid Development ◽  
Chemical Vapor ◽  
Radiation Detectors ◽  
Neutron Detectors ◽  
Future Directions ◽  
Materials Development ◽  
Late Twentieth ◽  
Manufacturing Techniques ◽  
Further Development

ABSTRACTSilicon carbide has long been a promising material for semiconductor applications in high-temperature environments. Although silicon carbide radiation detectors were demonstrated more than a half century ago, the unavailability of high-quality materials and device manufacturing techniques hindered further development until about twenty years ago. In the late twentieth century, the development of advanced SiC crystal growth and epitaxial chemical vapor deposition methods spurred rapid development of silicon carbide charged particle, X-ray and neutron detectors. The history and status of silicon carbide radiation detectors as well as the influence of materials and device packaging limitations on future detector development will be discussed. Specific silicon carbide materials development needs will be identified.

scholarly journals Machine Learning-Based Detection of Graphene Defects with Atomic Precision

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Bowen Zheng ◽  
Grace X. Gu
Keyword(s):  
Machine Learning ◽  
Material Design ◽  
Thermal Vibration ◽  
Single Atom ◽  
Complex Data ◽  
Alternative Approach ◽  
Atomic Precision ◽  
Data Driven Approach ◽  
New Material ◽  
Domain Discretization

AbstractDefects in graphene can profoundly impact its extraordinary properties, ultimately influencing the performances of graphene-based nanodevices. Methods to detect defects with atomic resolution in graphene can be technically demanding and involve complex sample preparations. An alternative approach is to observe the thermal vibration properties of the graphene sheet, which reflects defect information but in an implicit fashion. Machine learning, an emerging data-driven approach that offers solutions to learning hidden patterns from complex data, has been extensively applied in material design and discovery problems. In this paper, we propose a machine learning-based approach to detect graphene defects by discovering the hidden correlation between defect locations and thermal vibration features. Two prediction strategies are developed: an atom-based method which constructs data by atom indices, and a domain-based method which constructs data by domain discretization. Results show that while the atom-based method is capable of detecting a single-atom vacancy, the domain-based method can detect an unknown number of multiple vacancies up to atomic precision. Both methods can achieve approximately a 90% prediction accuracy on the reserved data for testing, indicating a promising extrapolation into unseen future graphene configurations. The proposed strategy offers promising solutions for the non-destructive evaluation of nanomaterials and accelerates new material discoveries.

scholarly journals MEMS Ultrasound Transducers for Endoscopic Photoacoustic Imaging Applications

Micromachines ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 928 ◽  
Author(s):  
Haoran Wang ◽  
Yifei Ma ◽  
Hao Yang ◽  
Huabei Jiang ◽  
Yingtao Ding ◽  
...  
Keyword(s):  
Microelectromechanical Systems ◽  
Vibration Mode ◽  
Photoacoustic Imaging ◽  
Rapid Development ◽  
Flexural Vibration ◽  
Ultrasound Transducers ◽  
Optical Contrast ◽  
Future Directions ◽  
Potential Applications ◽  
Mems Technology

Photoacoustic imaging (PAI) is drawing extensive attention and gaining rapid development as an emerging biomedical imaging technology because of its high spatial resolution, large imaging depth, and rich optical contrast. PAI has great potential applications in endoscopy, but the progress of endoscopic PAI was hindered by the challenges of manufacturing and assembling miniature imaging components. Over the last decade, microelectromechanical systems (MEMS) technology has greatly facilitated the development of photoacoustic endoscopes and extended the realm of applicability of the PAI. As the key component of photoacoustic endoscopes, micromachined ultrasound transducers (MUTs), including piezoelectric MUTs (pMUTs) and capacitive MUTs (cMUTs), have been developed and explored for endoscopic PAI applications. In this article, the recent progress of pMUTs (thickness extension mode and flexural vibration mode) and cMUTs are reviewed and discussed with their applications in endoscopic PAI. Current PAI endoscopes based on pMUTs and cMUTs are also introduced and compared. Finally, the remaining challenges and future directions of MEMS ultrasound transducers for endoscopic PAI applications are given.

Design of a New Family of Inorganic Compounds Ae2F2SnX3(Ae = Sr, Ba; X = S, Se) Using Rock Salt and Fluorite 2D Building Blocks

2006 ◽  
Vol 45 (2) ◽  
pp. 917-922 ◽  
Author(s):  
Houria Kabbour ◽  
Laurent Cario ◽  
Michel Danot ◽  
Alain Meerschaut
Keyword(s):  
Rock Salt ◽  
Inorganic Compounds ◽  
Building Blocks ◽  
New Family

scholarly journals The Attitude of Economic Students and Lecturers toward Economic English Material Based on Shariah Economy System

2017 ◽  
Vol 8 (4) ◽  
pp. 697
Author(s):  
Syamsul Una ◽  
Djamiah Husain ◽  
Abd. Halim
Keyword(s):  
Survey Research ◽  
Teaching And Learning ◽  
Positive Attitude ◽  
Material Design ◽  
Learning Material ◽  
New Material ◽  
Academic Year ◽  
Economy System

This research aimed to investigate Economic students and lecturers’ attitude toward economic English material based on shariah economy system. The material was the new material design that combined economic English in general and shariah economy concept in a teaching and learning material. This research is survey research. It was held at Economy Faculty of Dayanu Ikhsanuddin University Baubau Indonesia in 2015/2016 academic year. This research was limited to analyze both Economic students and lecturers’ attitude toward economic English material based on shariah economy system. The Participants of the study were 100 Economic students and 20 Economic lecturers. The instruments used were questionnaire and interview. All participants were invited to respond to questionnaires. And they then participated in follow-up interviews. The results of the study showed that the main score of students’ attitude was 42.24 and lecturers’ attitude was 41.50. From the main above indicated that both Economic students and lecturers had positive attitude toward economic English material based on shariah economy system.

scholarly journals Progress in Research of Flexible MEMS Microelectrodes for Neural Interface

2017 ◽  
Author(s):  
Long-Jun Tang ◽  
Hong-Chang Tian ◽  
Xiao-Yang Kang ◽  
Wen Hong ◽  
Jing-Quan Liu
Keyword(s):  
Performance Improvement ◽  
Rapid Development ◽  
Neural Interface ◽  
Fabrication Technology ◽  
Future Directions ◽  
Micro Fabrication ◽  
Micro Electro Mechanical Systems ◽  
Interface Modification ◽  
Tissue Interface ◽  
Electrophysiological Signal

With the rapid development of MEMS (Micro-electro-mechanical Systems) fabrication technologies, manifolds microelectrodes with various structures and functions have been designed and fabricated for applications in biomedical research, diagnosis and treatment through electrical stimulation and electrophysiological signal recording. The flexible MEMS microelectrodes exhibit multi-aspect excellent characteristics beyond stiff microelectrodes based on silicon or SU-8, which comprising: lighter weight, smaller volume, better conforming to neural tissue and lower fabrication cost. In this paper, we mainly reviewed key technologies on flexible MEMS microelectrodes for neural interface in recent years, including: design and fabrication technology, flexible MEMS microelectrodes with fluidic channels and electrode-tissue interface modification technology for performance improvement. Furthermore, the future directions of flexible MEMS microelectrodes for neural interface were described including transparent and stretchable microelectrodes integrated with multi-aspect functions and next-generation electrode-tissue interface modifications facilitated electrode efficacy and safety during implantation. Finally, the combinations among micro fabrication techniques with biomedical engineering and nanotechnology represented by flexible MEMS microelectrodes for neural interface will open a new gate to human lives and understanding of the world.

scholarly journals FABRICATION OF MICRO-WELL IN PMMA BY PCM AND X-RAY LITHOGRAPHY

2013 ◽  
pp. 289-293
Author(s):  
SACHIN BHOSALE ◽  
PROF. N.D. MISAL
Keyword(s):  
Low Cost ◽  
Rapid Development ◽  
Copper Sheet ◽  
Fluidic Channel ◽  
Processing Technologies ◽  
X Ray ◽  
Brass Sheet ◽  
Novel Processing ◽  
Increasing Demand ◽  
Micro Systems

During the last decade there has been a rapid development in Micro-Fabrication Technology driven by the need for low-cost Micro-Components and Micro-Systems. Micro-Components will be required in a range of new products such as medical devices, Micro-Well, Micro-Pillar Micro-Fluidic Systems. Applications for Micro-Systems have stimulated innovative developments, created new markets and a demand for low-cost components. These are particularly important in manufacturing industries such as the automotive, chemicals, medical instruments, computer parts and telecommunication sectors. The drive towards miniaturization places is increasing demand for new techniques and novel processing technologies. This paper describes the Manufacturing of X-ray Mask with Photo-Chemical Machining (PCM) and the Fabrication of Poly-Methyl-Meth-Acrylate (PMMA) structures with X-ray Lithography Technology. Fabrication of low cost X-ray mask has been done on Copper sheet and Brass sheet using PCM. X-ray Lithography is used to obtain high aspect ratio Micro-Well, Micro-Pillar and Micro-fluidic channel. Synchrotron radiation of Beam line BL-07 at INDUS-2, RRCAT Indore is the source of X-ray for Lithography.

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