• Progress in Superconductivity and Cryogenics
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• v.24 no.3
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• pp.12-18
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• 2022

In recent years, the impact of microplastics (MPs) on ecosystems is a serious problem. Since MPs are difficult to recover once they are dispersed into the environment, it is important to remove them at the source. We proposed a magnetic separation of primary MPs (plastics manufactured in minute sizes) sized 10-100 ㎛ that has not been removed in the sewage process, based on the magnetic seeding process. In this study, we used magnetite as a magnetic seeding agent, and conducted magnetic separation experiments in the continuous process using a superconducting solenoidal magnet to investigate the feasibility of practical magnetic separation system of MPs. As a result, 85% separation rate was obtained by continuous separation using high gradient magnetic separation (HGMS) with hydrophobically treated magnetite as a magnetic seeding agent.

• Investigative Magnetic Resonance Imaging
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• v.21 no.2
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• pp.119-124
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• 2017

Chromophobe renal cell carcinoma (RCC) is an uncommon subtype of RCC having a better prognosis than clear cell RCC. Although there are several reports of seeding metastasis of RCC after biopsy, seeding metastasis of chromophobe RCC after surgical resection has seldom been reported. Here, we describe a case of multiple seeding metastases in the abdomen and pelvis 78 months after robot-assisted laparoscopic partial nephrectomy, without prior history of biopsy for chromophobe RCC in the right kidney. As magnetic resonance imaging (MRI) of the pelvic mass showed a similar appearance to the primary renal mass and displayed separate margins with the rectum and prostate gland, we were able to make a diagnosis before pathologic confirmation.

• Progress in Superconductivity and Cryogenics
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• v.19 no.2
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• pp.14-18
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• 2017

This study presents three dimensional (3-D) seeding technique which is a modification of interior seeding. 3-D seeding is beneficial for shortening the processing period and enhancing the magnetic properties of REBCO bulk superconductors fabricated by melt growth. Oxygen channels were provided by using divided powder compacts instead of by using a rubber insert. Microstructure observations revealed that the grains grown from the seeds impinged each other and formed low angle grain boundaries of (001)/(001). It has been shown that the 3-D seeding technique reduces the volume fraction of a-c growth sector and thereby maximizes the area of a-b growth sector which attribute to the high magnetic characteristics of single grain REBCO bulk superconductors.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.251-254
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• 1999

A new multi-seeding process for the growth of YBa$_2$Cu$_3$Oxx single crystals was developed. This process introduces an additional heating step to peritectic temperature and a subsequent slow cooling step to the growth temperature following the point when the crystals contacted. The crystal growth was resumed thereafter. The results obtained with this new process were compared with those of the conventional growth process, in which materials were only kept at the growth temperature. It was observed that the liquid phase between crystals were almost completely eliminated, but that Y2ll grains were grown during this new process. There was no significant improvement in trapped magnetic field over the conventional process, which is believed to be due to the cracks generated during the oxygen heat treatment or to the growth of YBa$_2$Cu$_3$Ox grains.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.360-360
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• 2008

Steelmaking industry is widely known to use a lot of water and same amount of wastewater is generated. Although toxicity of wastewater from Steelmaking industry is low, it contains an amount of various organic materials and Fe-Oxides. It is important to recycle the wastewater because of water shortages and water pollution. In general, large-scale equipment is necessary to process the wastewater. On the other hand, superconducting high gradient magnetic separation (HGMS) system can process the wastewater in the small space. Superconducting HGMS system that had a purpose to purify the wastewater was assembled. Cryo-cooled Nb-Ti superconducting magnet was used for magnetic separator. This system can operate continuously because contaminated filters can keep on returning after cleaning. The various magnetic seeding reactions were investigated to increase the reactivity of coagulation. Filter cleaning system was developed to decrease the quantity of clean water. This research was supported by a grant from Korea Electrotechnology Research Institute, Republic of Korea.

• 한국초전도학회:학술대회논문집
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• v.9
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• pp.384-387
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• 1999

A new multi-seeding process for the growth of YBa$_2Cu_3O_x$ single crystals was developed. This process introduces an additional heating step to peritectic temperature and a subsequent slow cooling step to the growth temperature following the point when the crystals contacted. The crystal growth was resumed thereafter. The results obtained with this new process were compared with those of the conventional growth process, in which materials were only kept at the growth temperature. There was significant improvement in trapped magnetic field over the conventional multi-seeding process, which is believed to be due to complete elimination of liquid phase between crystals.

• Progress in Superconductivity and Cryogenics
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• v.24 no.3
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• pp.52-56
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• 2022

Single-grain (c-normal or c-parallel) and multi-grain YBCO superconductors were prepared by a melt growth process with/without seeding. The magnetic levitation force and trapped magnetic field at liquid N₂ temperature (77 K) of the YBCO superconductors were investigated. Samples for the levitation force measurement were zero-field cooled (ZFC) to 77 K, and samples for trapped field measurement were field-cooled (FC) using Nd magnets. As for the magnetic levitation force, the c-normal, single grain sample showed the largest value, whereas the multi-grain sample showed the lowest value. The trapped magnetic field of the c-normal and c-parallel single-grain samples was 4-5 times that of the multi-grain sample. In addition, as the external magnetic field (the number of magnets) increased, the both properties increased proportionally. These results were explained in terms of the orientation dependence of the levitation forces and the magnetic field trapping capability of the YBCO superconductor.

• Journal of Korean Neurosurgical Society
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• v.49 no.2
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• pp.124-127
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• 2011

A 43-year-old male presenting with headache and dizziness underwent craniotomy and gross total resection of an extraaxial tumor was achieved via left occipital interhemispheric approach. The tumor was diagnosed as papillary meningioma arising from the left falcotentorium with such pathologic characteristics of bronchoalveolar adenocarcinoma. At postoperative day 40, he developed generalized tonic clonic seizure and then progressed to a status epilepticus pattern. Brain magnetic resonance imaging showed irregular leptomeningeal enhancement with a significant peritumoral area. Through a cerebrospinal fluid (CSF) study, we identified the meningioma cells of the papillary type from the CSF. At the postoperative day 60, he fell into semicomatose state, and the computed tomography imaging showed low density on both cerebral hemispheres, except the basal ganglia and cerebellum, with overall brain swelling and an increased intracranial pressure. He died on the following day. We experienced a rare case of a papillary meningioma with leptomeningeal seeding.

• Investigative Magnetic Resonance Imaging
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• v.22 no.3
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• pp.177-181
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• 2018

Intraperitoneal metastatic hepatocellular carcinoma (HCC) is uncommon. Although rare, it can spontaneously rupture and cause hemoperitoneum similar to primary HCC in the liver. We present a case of intraperitoneal metastatic HCC that had spontaneously ruptured and appeared as an irregularly margined hemorrhagic mass with T1 high and T2 dark signal intensities on magnetic resonance imaging. Ruptured HCC is a life-threatening emergency with high mortality rate. Spontaneously ruptured intraperitoneal metastatic HCC should be considered if a patient with a history of HCC presents with acute abdomen, although rare.

• Progress in Superconductivity and Cryogenics
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• v.24 no.3
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• pp.1-6
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• 2022

The Magnetic Force Control MFC technology is very useful because of its physical treatment process. Especially the Magnetic Separation MS technology is expected to contribute to SDGs 2030, Circular Economy and Carbon neutral 2050 realization. This paper describes the review of the IFMFC activity from 2010.The IFMFC is organized by three local committees of researchers in Japan, China and Korea. The IFMFC aims to exchange the information of the development results using the MFC technology and to educate the young researchers. The forum has been held in every year around three countries. In 2020 and 2021, the forum was organized by Zoom online due to the COVID-19. The 134 presentations were made up to 2020.The breakdown of these presentations are categorized to the environment remediation52%, material resource37% and fundamental research/technology11%. The Super Conducting Magnet SCM development promotes the MFC technologies. There are some impressive backgrounds as to the brilliant SM technology applications for many different magnetism ; SCM development, High Gradient Magnetic Separation HGMS, magnetic seeding method and magneto-Archimedes effect. This paper reviews the IFMFC activity according to those presented presentations.