Sodium–Metal Halide and Sodium–Air Batteries

Ha ,, Seongmin,Kim ,, Jae‐,Kwang,Choi, Aram,Kim, Youngsik,Lee, Kyu Tae WILEY‐VCH Verlag 2014 ChemPhysChem Vol.15 No.10

<P>Impressive developments have been made in the past a few years toward the establishment of Na-ion batteries as next-generation energy-storage devices and replacements for Li-ion batteries. Na-based cells have attracted increasing attention owing to low production costs due to abundant sodium resources. However, applications of Na-ion batteries are limited to large-scale energy-storage systems because of their lower energy density compared to Li-ion batteries and their potential safety problems. Recently, Na-metal cells such as Na-metal halide and Na-air batteries have been considered to be promising for use in electric vehicles owing to good safety and high energy density, although less attention is focused on Na-metal cells than on Na-ion cells. This Minireview provides an overview of the fundamentals and recent progress in the fields of Na-metal halide and Na-air batteries, with the aim of providing a better understanding of new electrochemical systems.</P>

Fluorination methods and the properties of fluorinated carbon materials for use as lithium primary battery cathode materials

Seongmin Ha,임채훈,이영식 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.111 No.-

Fluorinated carbon is chemically stable due to its unique structure and polar C–F bonds; furthermore, fluorinatedcarbon has various characteristics, such as its thermal conductivity and hydrophobicity, and canexhibit different bond types, including ionic, semi-ionic, and covalent C–F2 and C–F3 bonds. Due to theabove properties, fluorinated carbon is mainly used as a cathode material for lithium primary batteries. Therefore, in this review, the synthesis methods of fluorinated carbon used as a cathode material for alithium primary battery and the various conditions of these methods are summarized. In addition, thephysical, chemical, and electrochemical properties of the cathode material of the lithium primary batteryare considered according to the type of fluorinated carbon, including graphite, graphene, carbon nanotubes,and carbon nanofibers.

Multiple classification by supplementing lesion region information on lesion of facial skin using deep learning

( Seongmin Ha ),( Jihee Kim ),( Hyun Seok Jeong ),( Su Jin Park ),( Hyuk-jae Chang ),( Sang Ho Oh ) 대한피부과학회 2020 대한피부과학회 학술발표대회집 Vol.72 No.1

Background: Deep learning (DL) research in dermatology has successfully provided several algorithms that accurately diagnose malignant and benign skin lesions using DL algorithms comparable to the level of human experts. Despite the latest advances, the current capacity of DL algorithm output has been restricted to a binary result; benign or malignant, and further diagnostic capability is limited Objectives: In this study, we used the DL algorithm which used CNN to develop an automated tool to provide a diagnosis of a facial skin lesion using the clinical images of 25 established diseases in an Asian population Methods: Digital clinical images which were confirmed by biopsy diagnosed at the Department of Dermatology of the Severance Hospital. In total, 31,170 (3,256 patients) digital clinical images who had one of 27 types of disorders Results: In this study, we aimed to classify facial skin lesions in 27 categories using the Yonsei test dataset, and the AUC values of the proposed model achieved 95.44 with its top-1 and top-5 predictions for an accuracy of 67.55% and 91.72%, respectively. The corresponding AUC values using the Edinburgh dataset were 87.84 with its top-1 and top-2 predictions of 54.31% and 78.79%, respectively Conclusion: Comparing to previously suggested models of DL, we have approached to distinguish numerous dermatologic manifestations occurring on the face. To further improve the accuracy on the expanded number of skin disorders by adding the size of our training dataset

Classification and accuracy of diagnosis of facial skin lesions based on deep learning

( Seongmin Ha ),( Minyoung Park ),( Sangho Oh ),( Hyuk-jae Chang ) 대한피부과학회 2018 대한피부과학회 학술발표대회집 Vol.70 No.2

Background: Deep learning is a branch of machine learning architectures that attempts to model high-level abstractions in data using multiple processing layers. Despite its application to many fields, the application of deep learning research in medicine is still limited. Objectives: To classify images of facial skin lesions using deep learning algorithms because facial skin lesions can be troublesome and worrisome to people. Methods: Photos of facial skin diseases from January 2, 2008 to December 30, 2016 at the Severance hospital were used after this study was approved by an IRB. Total 4,875 patients with facial skin lesions were selected based on clinicopathologic diagnosis of dermatologists. High frequent skin lesions on the face were divided into 10 main categories. Specific skin lesions were cut from the whole face image and 10,000 of training images and 2,000 of test images were separately split. For the deep learning training, DenseNet was used as a model. It is a neural network architecture where each layer is directly connected to every other layer in a feed-forward fashion and software code for this study was written in Python using the TensorFlow module. Results: Top-1 accuracy was 66.22±0.05% and AUC (average) was 0.7192±0.07 when the model showed the highest predicted value for a given 2,000 test images. Conclusion: Deep learning technique can be helpful to classify facial skin diseases and lead to accurate diagnosis of facial skin lesions.

Preparation and electrochemical characteristics of waste-tire char-based CFX for lithium-ion primary batteries

Ha Naeun,Jeong Seo Gyeong,Lim Chaehun,Ha Seongmin,Min Chung Gi,Choi Yusong,Lee Young-Seak 한국탄소학회 2023 Carbon Letters Vol.33 No.4

In this study, we investigate the opportunity of using waste tire char as a cathode material for lithium-ion primary batteries (LPBs). The char obtained by carbonizing waste tires was washed with acid and thermally fluorinated to produce CFX. The structural and chemical properties of the char and CFX were analyzed to evaluate the effect of thermal fluorination. The carbon structure of the char was increasingly converted to CFX structure as the fluorination temperature increased. In addition, the manufactured CFX-based LPBs were evaluated through electrochemical analysis. The discharge capacity of the CFX reached a maximum of 800 mAh/g, which is comparable to that of CFX-based LPBs manufactured from other carbon sources. On the basis of these results, the use of waste tire char-based CFX as a cathode material for LPBs is presented as a new opportunity in the field of waste tire recycling.

저선량ㆍ고화질 CT 영상 획득을 위한 반복적 재구성 기법의 정량적 평가

하성민(Seongmin Ha),심학준(Hackjoon Shim),장혁재(Hyuk-Jae Chang),김선규(Seonkyu Kim) 한국방송·미디어공학회 2013 한국방송공학회 학술발표대회 논문집 Vol.2013 No.6

CT(Computed Tomography)영상에서 선량과 화질은 중요한 요소이다. 선량은 환자에게 직접적으로 악영향을 끼치는 요소이며, 화질은 환자의 병변을 판단하는데 매우 중요하게 작용한다. 반복적 재구성 알고리즘을 이용하면 저선량 영상에서도 고화질의 영상을 얻을 수 있는지 FBP와 정량적, 정성적으로 비교하였다. 촬영 프로토콜은 관전압 80, 100, 120kVp에서 관전류를 동일하게 200mA로 촬영하여 획득하였으며, 정량적 평가를 위해 SD(Standard Deviation), SNR(Signal to Noise Ratio), MTF(Modulation Transfer Function)를 측정하여 분석하였다. 선량은 80kVp일 때 가장 낮았으며, 120kVp일 때 가장 높았다. 80kVp의 영상을 Toshiba 社의 <SUP> AIDR</SUP>3D(Adaptive Iterative Reduction integrated into SUREExposure)로 재구성하고, 120kVp의 영상에 FBP로 재구성한 다음 정량적 비교를 한 결과 AIDR 3D를 적용한 영상의 SD가 낮게 나왔으며, SNR이 높게 나타났고, MTF 곡선은 유사하게 나타났다. 그리고 FWHM(Full Width at Half Maximum) 값의 오차가 거의 없었다. 결론적으로 AIDR 3D는 저선량에서도 높은 화질을 나타냄을 확인하였다.

Correction: Preparation and electrochemical characteristics of waste‑tire char‑based CFX for lithium‑ion primary batteries

Naeun Ha,Seo Gyeong Jeong,Chaehun Lim,Seongmin Ha,Chung Gi Min,Yusong Choi,Young‑Seak Lee 한국탄소학회 2023 Carbon Letters Vol.33 No.6

산소 플라즈마 처리된 활성탄소의 세슘 이온 흡착

하성민 ( Seongmin Ha ),곽철환 ( Cheol Hwan Kwak ),임채훈 ( Chaehun Lim ),김석진 ( Seokjin Kim ),이영석 ( Young-seak Lee ) 한국공업화학회 2022 공업화학 Vol.33 No.1

산소 플라즈마 처리에 따른 활성탄소의 산소 관능기 도입이 세슘 이온 흡착 특성에 미치는 영향에 대하여 고찰하였다. 산소 플라즈마 처리 시 주파수, 전력 및 산소 가스 유량은 각각 100 kHz, 80 W 및 60 sccm으로 고정하였으며, 반응시간을 변수로 수행하였다. 본 실험조건에서는 산소 가스와의 반응시간이 10분일 때 C-O-C 및 O=C-O 결합 내 산소기능기 함량이 증가함에 따라 세슘 이온 흡착량이 증가하였다. 그러나 반응 시간이 15분일 때 산소 관능기 함량이 감소하게 되어 세슘 이온 흡착량이 오히려 감소되었다. 한편, 표면 처리된 활성탄소의 산소 함량과는 달리 그 비표면적 및 기공 특성은 산소 플라즈마 반응 시간에 따라 거의 영향을 받지 않았다. 결과적으로 산소 플라즈마 처리된 활성탄소는 미처리 활성탄소에 비하여 세슘 이온 제거율이 최대 97.3%까지 향상되었다. 이는 산소 플라즈마 처리로 활성탄소 표면에 도입된 C-O-C 및 O=C-O 결합 내 산소 기능기의 함량에 기인한 것으로 판단된다. The effect of introducing oxygen functional groups by oxygen plasma treatment of activated carbon on adsorption properties of cesium ions was investigated. During the oxygen plasma treatment, the frequency, power, and oxygen gas flow rates were fixed at 100 kHz, 80 W, and 60 sccm, respectively, while the reaction time was varied. Under the experimental conditions, the amount of cesium ion adsorption increased as the content of oxygen groups on C-O-C and O=C-O bonds increased when the reaction time with oxygen gas was 10 minutes. However, when the reaction time increased to 15 minutes, the oxygen functional group content decreased resulting in the decrease of the adsorbed cesium ion amount. On the other hand, unlike the oxygen content of the surface-treated activated carbon, the specific surface area and pore properties were hardly affected by the oxygen plasma reaction time. As a result, the oxygen plasma-treated activated carbon improved the cesium ion removal rate by up to 97.3% compared to that of the untreated activated carbon. This is considered to be due to the content of oxygen groups on C-O-C and O=C-O bonds introduced on the surface of the activated carbon through oxygen plasma treatment.

신라(新羅) 중고기(中古期) 서사(書寫)·각석(刻石)·입비(立碑) 전문가(專門家)의 분화(分化)와 서법(書法)·금석학(金石學)의 발달(發達)

하성민 ( Seongmin Ha ) 고려대학교 역사연구소 2022 사총 Vol.105 No.-

Transcription by transcribers at Myeonghwal Fortress Monument means the act itself of transcription for the sentences to be inscribed in monuments. Transcribers at Uljin Geobeolmorabi, Danyang Jeokseongbi and Changnyeong Monument Marking Visit of King Jinheung were real examples of transcription experts. And 'written monuments'(書石) could be found at 'Written Monuments Valley' of Uljin Cheonjeon-ri Monument Inscription' and monument writing (石書)-the same term of written monuments-at Erectors of Monument of Danyang Jeokseongbi. Here, 'written monuments' (書石) and monument writing (石書) mean inscribed monuments and monument inscription respectively, and inscribers at Uljin Geobeolmorabi were inscription experts. And figures registered as monument erectors at Uljin Geobeolmorabi and as erectors of inscribed monuments at Danyang Jeokseongbi were experts in monument erection. The existence of transcribers, inscribers, erectors at Uljin Geobeolmorabi demonstrated that job division in carrying out transcription, inscription, erection was done in the most reasonable and effective way. The process of monument erection as such changed to two phases of transcription and erection at Danyang Jeokseongbi. Thus, job division system of three phases of transcription - inscription-erection at Uljin Geobeolmorabi changed to two phases of transcription-erection at Danyang Jeokseongbi, making an effective erection process. This prevalence of variant letters a t epigraphic materials during the Middle Period(中古期) of Silla began from the distribution of copied Buddhist scriptures. This made one of Wei stele style prevailing in China then accommodated and used in Silla. So, development of graphonomy and exegetics then initiated from the work of exact interpretation of each Chinese letters copied in various letter styles of this Wei stele. As was the case in Goguryeo, this was possible because books favorably read at the time included Yupian and dictionaries of Jatong and Jarim. In particular, Yupian published by Gu Yewang during the Liang Dynasty illustrated completely-summarized regular script, making it highly appreciated. Furthermore, Jatong was also a letter book that summarized variant letters, making it ever more influential.

탄소섬유강화플라스틱 유래 폐 탄소섬유로 제조된 불화탄소 기반 리튬일차전지의 전기화학적 특성

하나은 ( Naeun Ha ),임채훈 ( Chaehun Lim ),하성민 ( Seongmin Ha ),명성재 ( Seongjae Myeong ),이영석 ( Young-seak Lee ) 한국공업화학회 2023 공업화학 Vol.34 No.5

본 연구에서는 탄소섬유강화플라스틱(CFRP)을 열분해하여 얻은 폐 탄소섬유를 이용하여 기상 불소화를 통해 불화탄소를 제조하고 리튬일차전지의 환원극 소재로 재활용하고자 하였다. 먼저 열분해로 얻은 폐 탄소섬유의 물리화학적 특성을 파악하였으며, 이 폐 탄소섬유에 기상 불소화 효과를 평가하기 위하여 불화탄소의 구조적, 화학적 특성을 분석하였다. XRD 분석에 의해 폐 탄소섬유의 육각망탄소 적층구조(002피크)는 기상 불소화의 온도가 증가함에 따라 점차 불화탄소 구조(001피크)로 전환되었음을 확인하였다. 이 불화탄소를 이용하여 제조된 리튬일차전지의 방전용량은 최대 862 mAh/g이었다. 이는 다른 탄소 재료로 제조한 불화탄소 기반 리튬이온차전지의 방전용량과 비교하였을 때 우수한 성능을 보였다. 이러한 결과는 폐 CFRP 기반 폐탄소섬유를 이용한 불화탄소는 리튬일차전지의 환원극 소재로 활용할 수 있을 것으로 여겨진다. In this study, waste carbon fiber obtained by pyrolysis of carbon fiber reinforced plastic (CFRP) was used to produce carbon fluoride through vapor phase fluorination and recycled as a reducing electrode material for lithium primary batteries. First, the physicochemical properties of the waste carbon fiber obtained by pyrolysis were determined, and the structural and chemical properties of carbon fluoride were analyzed to evaluate the effect of vapor phase fluorination on the waste carbon fiber. XRD analysis confirmed that the hexagonal network carbon laminated structure (002 peak) of the waste carbon fiber was gradually converted into a carbon fluoride structure (CF_X, 001 peak) as the temperature of gas phase fluorination increased. The discharge capacity of the lithium primary battery produced using this carbon fluoride was up to 862 mAh/g. This was compared to the discharge capacity of carbon fluoride-based Li-ion batteries made of other carbon materials. These results suggest that carbon fluoride made from waste CFRP-based carbon fibers can be used as a reducing electrode material for Li-ion batteries.