High Temperature Superconductivity in the Past Twenty Years Part 2——Towards to Practical Applications

After discovering high temperature superconducting materials 20 years ago, the preparation of applicable HTS materials has been pursued along with HTS mechanism and characteristic study. At present, the focus on the applied HTS technology has been moving to the industrial preparations from the laboratory research stage, and the technology has been well verified for practical applications from small to large scales. The fabrication techniques of engineering HTS materials are being industrialized; and various HTS devices are also on the way towards practical applications. This paper provides a comprehensive summary on the applied high temperature superconductivity with regard to various applicable HTS materials, their preparation techniques and charac- terization, and applications in a wide range.     

Summary of the First Generation High Temperature Superconducting Wire： Processing, Characterization and Applications

Silver-clad （Bi,Pb）2Sr2Ca2Cu3O10＋x long wires produced by powder-in-tube techniques, which have been recognized as the first generation of the High Temperature Superconducting （HTS） wires, are expected to apply widely especially in strong current applications. In this work, the processing, characterization and application of the silver-clad （Bi,Pb）2Sr2Ca2Cu3Ol0＋x HTS wires are summarized. The HTS wires are fabricated using the combination of powder-in-tube technique, and the resulting wires are fully characterized by the means of chemical analyses, microstructural observation, electrical and magnetic measurements. The relationship among fabrication parameters, chemical and microstructural characteristics, and electrical and magnetic properties are analyzed. Applications of the HTS wires have also been introduced according to their strong current behaviors with various prototype devices made.     

Development of HTS Transformers and a 10 kVA HTS Transformer Prototype Design

With the improvement of high temperature superconductor （HTS） practical performance, research and development concerning the applications of HTS transformers have been progressed actively worldwide. This paper provides a comprehensive summary on various HTS transformers, and studies the design of a single-phase 10 kVA （220V/24V） HTS transformer prototype to verify HTS for practical transformer applications.     

Hybrid functional microfibers for textile electronics and biosensors

Fibers are low-cost substrates that are abundantly used in our daily lives.This review highlights recent advances in the fabrication and application of multifunctional fibers to achieve fibers with unique functions for specific applications ranging from textile electronics to biomedical applications.By incorporating various nanomaterials such as carbon nanomaterials,metallic nanomaterials,and hydrogel-based biomaterials,the functions of fibers can be precisely engineered.This review also highlights the performance of the functional fibers and electronic materials incorporated with textiles and demonstrates their practical application in pressure/tensile sensors,chemical/biosensors,and drug delivery.Textile technologies in which fibers containing biological factors and cells are formed and assembled into constructions with biomimetic properties have attracted substantial attention in the field of tissue engineering.We also discuss the current limitations of functional textile-based devices and their prospects for use in various future applications.     

Skin-inspired electronics:emerging semiconductor devices and systems

Current electronics are driven by advanced microfabrication for fast and efficient information processing.In spite of high performance,these wafer-based devices are rigid,non-degradable,and unable to autonomous repair.Skin-inspired electronics have emerged as a new class of devices and systems for next-generation flexible and wearable electronics.The technology gains inspiration from the structures,properties,and sensing mechanisms of the skin,which may find a broad range of applications in cutting-edge fields such as healthcare monitoring,human-machine interface,and soft robotics/prostheses.Practical demands have fueled the development of electronic materials with skin-like properties in terms of stretchability,self-healing capability,and biodegradability.These materials provide the basis for functional sensors with innovative and biomimetic designs.Further system-level integrations and optimizations enable new forms of electronics for real-world applications.This review summarizes recent advancements in this active area and speculates on future directions.     

High Tc Superconductor Theoretical Models and Electromagnetic Flux Characteristics

High Tc Superconductors （HTS） have special electromagnetic characteristics and phenomena. Effort has been made in order to theoretically understand the appfied HTS superconductivity and HTS behaviors for practical appfications, various theoretical models related to the HTS electromagnetic properties have been developed. The theoretical models and analytic methods are summarized with regard to understanding the HTS magnetic flux characteristic which is one of the most critical issues related to HTS appfications such as for HTS magnetic levitation application.     

Dynamics of Exciton Transport in Two-Dimensional Materials

In recent years, two-dimensional(2D) materials have attracted extensive interests due to the large exciton binding energy different from bulk materials. Many peculiar properties have been discovered that have farreaching perspectives in the next generation of optoelectronic devices. In this review, we introduce the forms of exciton existence in 2D materials and several promising 2D materials with good applications at first. Then, we summarize relevant contemporary tools for probing exciton dynam...     

Structural Parameter Optimization of Multilayer Conductors in HTS Cable

In this paper, the design optimization of the structural parameters of multilayer conductors in high temperature superconducting （HTS） cable is reviewed. Various optimization methods, such as the particle swarm optimization （PSO）, the genetic algorithm （GA）, and a robust optimization method based on design for six sigma （DFSS）, have been applied to realize uniform current distribution among the multilayer HTS conductors. The continuous and discrete variables, such as the winding angle, radius, and winding direction of each layer, are chosen as the design parameters. Under the constraints of the mechanical properties and critical current, PSO is proven to be a more powerful tool than GA for structural parameter optimization, and DFSS can not only achieve a uniform current distribution, but also improve significantly the reliability and robustness of the HTS cable quality.     

High Temperature Superconductivity in the Past Twenty Years Part 1——Discovery, Material, and Theory

Twenty years after the discovery of hightemperature superconductors （HTSs）, the HTS materials now have been well developed. Meanwhile the mechanism of superconductivity is still one of the topical interests in physics. The achievements made on HTS materials and theories during the last twenty years are reviewed comprehensively in this paper.     

Preface to the Special Topic on Semiconducting Materials Genome: New Concepts and Discoveries

Advanced semiconducting materials have many applications in information technology and clean energy,thus they are critical to sustained economic and environmental development.However,in the past,many important technology-enabling materials were discovered by trial and error,which tends to take long time and high cost to discover and move them from research laboratory to market.Therefore,accelerating the pace of discovery and deployment of advanced semiconducting materials are crucial to achieving rapid development in the 21st century.In recent years,great progresses have been made in theory and computational algorithms to discover and design new functional materials using materials genome techniques and high-throughput calculations.These recent advances in the ability of new material discoveries have transformed our understanding of the field and provided both opportunity and challenge in developing new semiconductor technology.     

High Tc Superconducting Materials for Strong Current Applications: Approach at the First Stage

Strong current and large-scale application is the most important prospect of high Tc superconductors (HTS). Practical HTS samples in various forms have been produced with high critical currents operated at economic cryogenic temperatures. Engineering applications of those HTS materials have been studied with various HTS prototype devices. The applicable HTS materials produced in different forms are verified in this paper with regard to their strong current characterizations, and the HTS applications are summarized along with the HTS prototypes made.     

Summary of the First Generation High Temperature Superconducting Wire: Processing,Characterization and Applications

Silver-clad (Bi,Pb)2Sr2Ca2Cu3O10+x long wires produced by powder-in-tube techniques, which have been recognized as the first generation of the High Temperature Superconducting (HTS) wires, are expected to apply widely especially in strong current applications. In this work, the processing, characterization and application of the silver-clad (Bi,Pb)2Sr2Ca2Cu3O10+x HTS wires are summarized. The HTS wires are fabricated using the combination of powder-in-tube technique, and the resulting wires are fully characterized by the means of chemical analyses, microstructural observation, electrical and magnetic measurements. The relationship among fabrication parameters, chemical and microstructural characteristics, and electrical and magnetic properties are analyzed. Applications of the HTS wires have also been introduced according to their strong current behaviors with various prototype devices made.     

High Tc Superconductor Theoretical Models and Electromagnetic Flux Characteristics

High Tc Superconductors (HTS) have special electromagnetic characteristics and phenomena. Effort has been made in order to theoretically understand the applied HTS superconductivity and HTS behaviors for practical applications, various theoretical models related to the HTS electromagnetic properties have been developed. The theoretical models and analytic methods are summarized with regard to understanding the HTS magnetic flux characteristic which is one of the most critical issues related to HTS applications such as for HTS magnetic levitation application.     

High temperature superconductivity: Magnets and applications of naval interest

The Navy has had a long standing interest in power applications of superconductivity. Recent advances in high temperature superconducting (HTS) materials have caused the Navy science and technology community to assess the potential of HTS magnets for Naval applications. A program has begun to test HTS conductors and magnets in order to determine realistic performance expectations from which to determine proper systems integration. This paper presents some early results of industrially produced HTS magnets and discusses possible Naval applications. Speculative application toward magneto-hydrodynamic (MHD) propulsion is also discussed-specifically with respect to HTS materials.     

Features and Prototypes of HTS High Q Resonant Circuit

High Tc superconductor (HTS) technology has been used to develop a unique high Q resonant circuit. Such circuit or device has some special characteristics such as very high voltage generation. Theoretical study and experimental approaches have proceeded for the concept verification. This paper presents the theory about this high Q resonant circuit. The operation principle of the circuit is described. A practical prototype for HTS high voltage generation is also demonstrated. The experiment result shows that very high voltages can be achieved by the developed method using HTS technology.     

Features and Prototypes of HTS High Q Resonant Circuit

High Te superconductor （HTS） technology has been used to develop a unique high Q resonant circuit. Such circuit or device has some special characteristics such as very high voltage generation. Theoretical study and experimental approaches have proceeded for the concept verification. This paper presents the theory about this high Q resonant circuit. The operation principle of the circuit is described. A practical prototype for HTS high voltage generation is also demonstrated. The experiment result shows that very high voltages can be achieved by the developed method using HTS technology.     

SuperPower's YBCO Coated High-Temperature Superconducting (HTS) Wire and Magnet Applications

Recent developments in second-generation (2G) HTS wire and coil technology are presented highlighting the ability of 2G HTS wire to function under demanding operating conditions associated with many applications including linear motors for transportation. The challenges of use in various coil constructions and applications are discussed. The 2G wire architecture of a structural substrate, buffer stack, HTS layer, and stabilization enables the 2G wire to tolerate high stress levels while providing the high current density required for lightweight, compact magnets. The high winding current density that is available with SuperPower's thin (0.1 mm) 2G HTS wire has been utilized in several coil demonstrations, including one generating central fields in excess of 26.8 T. The ability of the wire to be tailored (stabilization, insulation, ac losses) to fit various operating parameters will also be discussed.