• 천문학회보
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• 제45권1호
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• pp.45.1-45.1
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• 2020

Light bridges (LBs) are relatively bright structures that divide sunspot umbrae into two or more parts. Chromospheric LBs are known to be associated with various activities including fan-shaped jet-like ejections and brightenings. Although magnetic reconnection is frequently suggested to be responsible for such activities, not many studies presented firm evidence to support the scenario. We carry out magnetic field measurements and imaging spectroscopy of a LB where fan-shaped jet-like ejections occur with co-spatial brightenings at their footpoints. We study their fine photospheric structures and magnetic field changes using TiO images, Near-InfraRed Imaging Spectropolarimeter data, and Hα data taken by the 1.6 m Goode Solar Telescope. As a result, we detect magnetic flux emergence in the LB that is of opposite polarity to that of the sunspot. The new flux cancels with the pre-existing flux at a rate of 5.6×1018 Mx hr-1. Both recurrent jet-like ejections and their footpoint brightenings are initiated at the vicinity of the magnetic cancellation, and show apparent horizontal extension along the LB at a projected speed of 4.3 km s-1 to form the fan-shaped appearance. Based on these observations, we suggest that the fan-shaped ejections may have resulted due to slipping reconnection between the new flux emerging in the LB and the ambient sunspot field.

• Korean Journal of Radiology
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• 제22권12호
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• pp.2094-2123
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• 2021

Incidental thyroid nodules are commonly detected on ultrasonography (US). This has contributed to the rapidly rising incidence of low-risk papillary thyroid carcinoma over the last 20 years. The appropriate diagnosis and management of these patients is based on the risk factors related to the patients as well as the thyroid nodules. The Korean Society of Thyroid Radiology (KSThR) published consensus recommendations for US-based management of thyroid nodules in 2011 and revised them in 2016. These guidelines have been used as the standard guidelines in Korea. However, recent advances in the diagnosis and management of thyroid nodules have necessitated the revision of the original recommendations. The task force of the KSThR has revised the Korean Thyroid Imaging Reporting and Data System and recommendations for US lexicon, biopsy criteria, US criteria of extrathyroidal extension, optimal thyroid computed tomography protocol, and US follow-up of thyroid nodules before and after biopsy. The biopsy criteria were revised to reduce unnecessary biopsies for benign nodules while maintaining an appropriate sensitivity for the detection of malignant tumors in small (1-2 cm) thyroid nodules. The goal of these recommendations is to provide the optimal scientific evidence and expert opinion consensus regarding US-based diagnosis and management of thyroid nodules.

• 대한디지털의료영상학회논문지
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• 제13권3호
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• pp.127-132
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• 2011

This is to improve the complicate process of the existing CD copy flow in Department of Radiology. It is also to improve the medical service of the hospital to secure private information of patients. Survey: The patients who ask for CD copies in the Department of Radiology of this hospital(for 6 months in 2010). Time: Comparing the total amount of time of the previous and the modified CD copy flow. Using the SPSS 12.0 program for testing significance of independent two-samples t-test. Private information: Introducing the identification-system based on the medical law to supplement the security of personal information of patients. There was manifold complaints due to receipt and issuing the prescription in Admission and Discharging office and outpatient department. The time has been approximately 50% reduced from 70 mistunes to 32 mistunes due to simplifying the routes. The security of the personal information has been supplemented by let patients submit documentary evidence based on the medical law. The service in the hospital has been improved as a result of simplifying the whole process of the routes and receipt process. Therefore, the each stage of waiting time has been decreased. In addition, the personal information of the patients has been more secured.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.53-53
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• 2011

This paper describes results for surface and bulk characterization of the most promising thin film solar cell material for high performance devices, (Ag,Cu) (In,Ga) Se2 (ACIGS). This material in particular exhibits a range of exotic behaviors. The surface and general materials science of the material also has direct implications for the operation of solar cells based upon it. Some of the techniques and results described will include scanning probe (AFM, STM, KPFM) measurements of epitaxial films of different surface orientations, photoelectron spectroscopy and inverse photoemission, Auger electron spectroscopy, and more. Bulk measurements are included as support for the surface measurements such as cathodoluminescence imaging around grain boundaries and showing surface recombination effects, and transmission electron microscopy to verify the surface growth behaviors to be equilibrium rather than kinetic phenomena. The results show that the polar close packed surface of CIGS is the lowest energy surface by far. This surface is expected to be reconstructed to eliminate the surface charge. However, the AgInSe2 compound has yielded excellent atomic-resolution images of the surface with no evidence of surface reconstruction. Similar imaging of CuInSe2 has proven more difficult and no atomic resolution images have been obtained, although current imaging tunneling spectroscopy images show electronic structure variations on the atomic scale. A discussion of the reasons why this may be the case is given. The surface composition and grain boundary compositions match the bulk chemistry exactly in as-grow films. However, the deposition of the heterojunction forming the device alters this chemistry, leading to a strongly n-type surface. This also directly explains unpinning of the Fermi level and the operation of the resulting devices when heterojunctions are formed with the CIGS. These results are linked to device performance through simulation of the characteristic operating behaviors of the cells using models developed in my laboratory.

• Clinics in Shoulder and Elbow
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• 제21권4호
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• pp.186-191
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• 2018

Background: To determine the normal range of humeral head positioning on magnetic resonance imaging (MRI). Methods: We selected normal subjects (64 patients; group A) to study the normal range of humeral head positioning on the glenoid by MRI measurements. To compare the MRI measurement method with the computed tomography (CT), we selected group B (70 patients) who underwent both MRI and CT. We measured the humeral-scapular alignment (HSA) and the humeral-glenoid alignment (HGA). Results: The HSA in the control group was $1.47{\pm}1.05mm$, and the HGA with and without reconstruction were $1.15{\pm}0.65mm$ and $1.03{\pm}0.59mm$, respectively, on MRI. In the test group, HSA was $2.67{\pm}1.47mm$ and HGA with and without reconstruction was $1.58{\pm}1.16mm$ and $1.49{\pm}1.08mm$, on MRI. On CT, the HSA was $1.72{\pm}1.01mm$, and HGA with and without reconstruction were $1.54{\pm}0.96mm$ and $1.59{\pm}0.93mm$, respectively. HSA was significantly different according to image modality (p=0.0006), but HGA was not significantly different regardless of reconstruction (p=0.8836 and 0.9234). Conclusions: Although additional CT scans can be taken to measure decentering in patients with rotator cuff tears, reliable measurements can be obtained with MRI alone. When using MRI, it is better to use HGA, which is a more reliable measurement value based on the comparison with CT measurement (study design: Study of Diagnostic Test; Level of evidence II).

• Journal of Gastric Cancer
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• 제14권2호
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• pp.87-104
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• 2014

Although gastric cancer is quite common in Korea, the treatment outcome is relatively favorable compared to those in western countries. However, there are currently no Korean multidisciplinary guidelines for gastric cancer. Experts from related societies developed guidelines de novo to meet Korean circumstances and requirements, including 23 recommendation statements for diagnosis (n=9) and treatment (n=14) based on relevant key questions. The quality of the evidence was rated according to the GRADE evidence evaluation framework: the evidence levels were based on a systematic review of the literature, and the recommendation grades were classified as either strong or weak. The applicability of the guidelines was considered to meet patients' view and preferences in the context of Korea. The topics of the guidelines cover diagnostic modalities (endoscopy, endoscopic ultrasound, and radiologic diagnosis), treatment modalities (surgery, therapeutic endoscopy, chemotherapy, and radiotherapy), and pathologic evaluation. An external review of the guidelines was conducted during the finalization phase.

• Annals of Clinical Neurophysiology
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• 제14권1호
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• pp.1-6
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• 2012

Low back pain is a common clinical condition with heterogeneous causes and challenges to manage. High prevalence and numerous assessments result in an enormous socioeconomic burden. Clinician must conduct efficient and stepwise evaluation process to rule out serious spinal pathology, neurologic involvement, and identify risk factors for chronicity. The process can be achieved through the focused history taking and physical examination. Certain factors related to serious spinal pathology include age (>50 years), trauma, unexplained fever, recent urinary or skin infection, unrelenting night or rest pain, unexplained weight loss, osteoporosis, immunosuppression, steroid use, and widespread neurological symptoms. In non-specific low back pain, diagnostic imaging and laboratory studies are often unnecessary and can disturb an appropriate management. For the management of acute low back pain, patient education and medication such as acetaminophen, non-steroidal anti-inflammatory drugs, and muscle relaxants are recommended. For chronic low back pain, behavior therapy, back exercise, and spinal manipulation are beneficial. The evidence based approach could improve success rate of management, result in prevention of acute low back pain from being chronic intractable pain.

• Journal of Korean Neurosurgical Society
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• 제49권1호
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• pp.71-74
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• 2011

A 34-year-old female patient was presented with leg and hip pain for 6 months as well as voiding difficulty for 1 year. Magnetic resonance imaging revealed a well-demarcated mass lesion at L2-3. The mass was hypo-intense on T1- and T2-weighted images with homogeneous gadolinium enhancement. Surgery was performed with the presumptive diagnosis of intradural extramedullary meningioma. Complete tumor removal was possible due to lack of dural adhesion of the tumor. Histologic diagnosis was clear cell meningioma, a rare and newly included World Health Organization classification of meningioma usually affecting younger patients. During postoperative 2 years, the patient has shown no evidence of recurrence. We report a rare case of cauda equina clear cell meningioma without any dural attachment.

• 한국임상수의학회지
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• 제26권1호
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• pp.91-94
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• 2009

A 6-year-old, intact female mixed dog was referred to Veterinary Medical Teaching Hospital of Gyeongsang National University due to vomiting, anorexia, depression of 1 month's duration. On abdominal radiography, numerous irregularly marginated mineralized branching structures were present within the liver. On ultrasonography, irregular hyperechoic spots with an strong acoustic shadow was identified, but evidence of ductal dilatation was absent. Based on radiography and ultrasonography, intrahepatic gallstones were diagnosed incidentally.

• 천문학회보
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• 제42권2호
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• pp.49.2-49.2
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• 2017

With support from the K-GMT science program (PID: GN-2016B-Q-14), we conducted observations of active asteroid 354P/LINEAR (2010 A2) when it made its closest approach to Earth (i.e., the geocentric distance of 1.06 au on 2017 January 27-28). Taking advantage of the best observing geometry since the discovery, we obtained the first evidence for the rotational status of the largest fragment (~120 m in diameter), which was slowly rotating, that is, the rotational period of 11.36 hours. In addition, we succeed in direct imaging of 10 sub-fragments (~20 m in diameter or larger). Based on these new observational results, we conjecture that this active asteroid was created as a result of catastrophic collision among unknown asteroids. The details of this work are given in Astrophysical Journal Letters, 842, L23.