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Fabrication of 6-superconducting layered HTS wire for high engineering critical current density
Gwantae Kim,Hongsoo Ha,Hosup Kim,Sangsoo Oh,Jaehun Lee,Seunghyun Moon 한국초전도저온공학회 2021 초전도와 저온공학 Vol.23 No.4
Recently, cable conductors composed of numerous coated conductors have been developed to transport huge current for largescale applications, for example accelerators and fusion reactors. Various cable conductors such as CORC (Conductor on round core), Roebel Cable, and TSTC (Twisted stacked tape cable) have been designed and tested to apply for large-scale applications. But, these cable conductors cannot improve the engineering critical current density (Je) because they are made by simple stacking of coated conductors. In this study, multi-HTS (High temperature superconductor) layers on one substrate (MHOS) wire was fabricated to increase the engineering critical current density by using the exfoliation of superconducting layer from substrate and silver diffusion bonding method. By the repetition of these processes, the 10 m long 6-layer MHOS conductor was successfully fabricated without any intermediate layers like buffer or solder. 6-layer MHOS conductor exhibited a high critical current of 2,460A/12mm-w. and high engineering critical current density of 1,367A/mm2 at liquid nitrogen temperature.
Fabrication of 6-superconducting layered HTS wire for high engineering critical current density
Gwantae Kim,Hongsoo Ha,Hosup Kim,Sangsoo Oh,Jaehun Lee,Seunghyun Moon 한국초전도저온학회 2021 한국초전도저온공학회논문지 Vol.23 No.4
Recently, cable conductors composed of numerous coated conductors have been developed to transport huge current for largescale applications, for example accelerators and fusion reactors. Various cable conductors such as CORC (Conductor on roundcore), Roebel Cable, and TSTC (Twisted stacked tape cable) have been designed and tested to apply for large-scale applications. But, these cable conductors cannot improve the engineering critical current density (Je) because they are made by simple stackingof coated conductors. In this study, multi-HTS (High temperature superconductor) layers on one substrate (MHOS) wire wasfabricated to increase the engineering critical current density by using the exfoliation of superconducting layer from substrate andsilver diffusion bonding method. By the repetition of these processes, the 10 m long 6-layer MHOS conductor was successfullyfabricated without any intermediate layers like buffer or solder. 6-layer MHOS conductor exhibited a high critical current of2,460A/12mm-w. and high engineering critical current density of 1,367A/mm2at liquid nitrogen temperature.
Gwantae Kim,Insung Park,Jeongtae Kim,Hosup Kim,Jaehun Lee,Hongsoo Ha 한국초전도저온학회 2023 한국초전도저온공학회논문지 Vol.25 No.4
Until now, many research activities have been conducted to commercialize high-temperature superconducting (HTS) wires for electric applications. Most of all researchers have focused on enhancing the piece length, critical current density, mechanical strength, and throughput of HTS wires. Recently, HTS magnet for generating high magnetic field shows degraded performance due to the deformation of HTS wire by high electro-magnetic force. The deformation can be derived from widthwise thickness non-uniformity of HTS wire mainly caused by wet processes such as electro-polishing of metal substrate and electro-plating of copper. Gradient sputtering process is designed to improve the thickness uniformity of HTS wire along the width direction. Copper stabilizing layer is deposited on HTS wire covered with specially designed mask. In order to evaluate the thickness uniformity of HTS wire after gradient sputtering process, the thickness distribution across the width is measured by using the optical microscope. The results show that the gradient deposition process is an effective method for improving the thickness uniformity of HTS wire.
Jeongtae Kim,Insung Park,Gwantae Kim,Myunghwan Sohn,Sanghoon Lee,Arim Byun,Jin-sil Choi,Taekyu Kim,Hongsoo Ha 한국초전도저온학회 2023 한국초전도저온공학회논문지 Vol.25 No.4
The manufacturing process of antibody drugs comprises two main stages: the upstream process for antibody cultivation and the downstream process for antibody extraction. The domestic bio industry has excellent technology for the upstream process. However, it relies on the technology of foreign countries to execute downstream process such as affinity chromatography. Furthermore, there are no domestic companies capable of producing the equipment for affinity chromatography. High gradient magnetic separation technology using a high temperature superconducting magnet as a novel antibody separation and purification technology is introduced to substitute for the traditional technology of affinity chromatography. A specially designed magnetic filter was equipped in the bore of the superconducting magnet enabling the continuous magnetic separation of nano-sized paramagnetic beads that can be used as affinity magnetic nano beads for antibodies. To optimize the magnetic filter that captures superparamagnetic nanoparticles effectively, various shapes and materials were examined for the magnetic filter. The result of magnetic separation experiments show that the maximum separation and recovery ratio of superparamagnetic nanoparticles are 99.2 %, and 99.07 %, respectively under magnetic field (3 T) and flow rate (600 litter/hr).
The fabrication of bulk magnet stacked with HTS tapes for the magnetic levitation
Park, Insung,Kim, Gwantae,Kim, Kyeongdeok,Sim, Kideok,Ha, Hongsoo 한국초전도저온학회 2022 한국초전도저온공학회논문지 Vol.24 No.3
With the innovative development of bio, pharmaceutical, and semiconductor technologies, it is essential to demand a next-generation transfer system that minimizes dust and vibrations generated during the manufacturing process. In order to develop dust-free and non-contact transfer systems, the high temperature superconductor (HTS) bulks have been applied as a magnet for levitation. However, sintered HTS bulk magnets are limited in their applications due to their relatively low critical current density (J<sub>c</sub>) of several kA/cm<sup>2</sup> and low mechanical properties as a ceramic material. In addition, during cooling to cryogenic temperatures repeatedly, cracks and damage may occur by thermal shock. On the other hand, the bulk magnets made by stacked HTS tapes have various advantages, such as relatively high mechanical properties by alternate stacking of the metal and ceramic layer, high magnetic levitation performance by using coated conductors with high J<sub>c</sub> of several MA/cm<sup>2</sup>, consistent superconducting properties, miniaturization, light-weight, etc. In this study, we tried to fabricate HTS tapes stacked bulk magnets with 60 mm × 60 mm area and various numbers of HTS tape stacked layers for magnetic levitation. In order to examine the levitation forces of bulk magnets stacked with HTS tapes from 1 to 16 layers, specialized force measurement apparatus was made and adapted to measure the levitation force. By increasing the number of HTS tapes stacked layers, the levitation force of bulk magnet become larger. 16 HTS tapes stacked bulk magnets show promising levitation force of about 23.5 N, 6.538 kPa at 10 mm of levitated distance from NdFeB permanent magnet.
바이오매스 합성가스 정제를 위한 습식전기집진기의 개발 및 정제 능력 평가
윤여성 ( Yeoseong Yoon ),강구 ( Ku Kang ),김관태 ( Gwantae Kim ),홍성구 ( Seonggu Hong ) 한국농공학회 2017 한국농공학회 학술대회초록집 Vol.2017 No.-
최근 석유, 천연가스 등 화석연료의 가채 매장량의 한계와 함께 2015년 파리협정 (Paris Climate Change Accord)의 체결로 신기후체제에 대응하기 위하여 신재생에너지를 이용한 에너지 생산기술개발에 많은 관심과 연구를 수행하고 있으며, 특히 바이오매스는 탄소 중립성, 지속 가능성, 광범위한 이용 가능성으로 인해 실현 가능한 신재생에너지로 간주되고 있다. 바이오매스를 이용한 에너지활용 기술 가운데 가스화 기술은 고체연료를 산소가 충분하지 않은 조건에서 연소하여 CO와 H<sub>2</sub>가 주성분인 합성가스를 생산하는 열화학적 변환기술로, 반응시간이 매우 짧고 단위 부피당 처리량이 높으며, 공정폐기물 발생량이 매우 적은 장점이 있다. 하지만 생산된 합성가스에는 미세입자와 타르로 이루어진 오염물질도 같이 함유하고 있기 때문에, 합성가스를 엔진을 통한 발전, 스팀, 수소 및 화학제품 생산으로 활용하기 위해서는 고효율의 타르 정제가 필요하다. 이에 본 연구에서는 분무 방식의 습식전기집진기를 개발하고, 습식전기집진기의 합성가스 내 타르 및 분진의 제거 능력을 평가하고자 하였다. 이를 위해 함수율 20%의 우드칩을 이용하여 합성가스를 생산하였고, 습식전기집진기를 통과한 합성가스는 GC-FID (Gas Chromatography - Flame Ionization Detector)를 이용하여 타르 (Benzene, Toluene, Ethyl-benzene, Phenol, Indene, Naphthalene, Bi-phenyl, N-tetradecane)를 분석하였고, 그 결과를 통해 개발한 습식전기집진기의 정제능력을 평가하였다.