Energy storage capabilities of nitrogen-enriched pyropolymer nanoparticles fabricated through rapid pyrolysis

Yun, Young Soo,Kim, Yu Hyun,Song, Min Yeong,Kim, Na Rae,Ku, Kyojin,An, Ji Su,Kang, Kisuk,Choi, Hyoung Jin,Jin, Hyoung-Joon Elsevier 2016 Journal of Power Sources Vol.331 No.-

<P><B>Abstract</B></P> <P>Nanostructured pyropolymers contain significant amounts of redox-active heteroatoms, have high specific surface areas, and a defective carbon microstructure, indicating good potential for pseudocapacitive charge storage. In this study, nitrogen-enriched pyropolymer nanoparticles (N-PNs-50) are fabricated from polyaniline nanotubes through rapid pyrolysis at 50 °C min<SUP>−1</SUP>. N-PNs-50 exhibit a nitrogen content of 9.8 wt%, a high specific surface area of 875.8 m<SUP>2</SUP> g<SUP>−1</SUP>, and an amorphous carbon structure with an I<SUB> <I>D</I> </SUB>/I<SUB> <I>G</I> </SUB> intensity ratio of 0.95. These unique characteristics lead to good electrochemical performances, in which reversible capacities of 660 and 255 mAh g<SUP>−1</SUP> are achieved for Li-ion and Na-ion storage, respectively, with favorable voltage characteristics (<1.5 V for Li-ions and <1.2 V for Na-ions). This study provides a more feasible production method for nitrogen-doped pyropolymers and their practicable electrochemical performances for use as an anode in energy storage devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Nanostructured pyropolymers (N-PNs-50) were fabricated by rapid pyrolysis. </LI> <LI> N-PNs-50 exhibited a nitrogen content of 9.8 wt% and amorphous carbon structure. </LI> <LI> N-PNs-50 exhibited a high specific surface area of 875.8 m<SUP>2</SUP> g<SUP>−1</SUP>. </LI> <LI> 660 and 255 mAh g<SUP>−1</SUP> were achieved for Li-ion and Na-ion storage, respectively. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Nitrogen-enriched pyropolymer nanoparticles (N-PNs-50) were fabricated from polyaniline nanotubes through rapid pyrolysis at 50 °C min<SUP>−1</SUP>, showing superior electrochemical performances.</P> <P>[DISPLAY OMISSION]</P>

Hierarchically nanoporous pyropolymer nanofibers for surface-induced sodium-ion storage

Yoon, Hyeon Ji,Lee, Min Eui,Kim, Na Rae,Yang, Seung Jae,Jin, Hyoung-Joon,Yun, Young Soo Pergamon Press 2017 Electrochimica Acta Vol. No.

<P><B>Abstract</B></P> <P>Surface-driven charge storage materials based on both electrochemical double layer (EDL) formation and pseudocapacitive behavior can deliver high energy and power capabilities with long-lasting cycling performance. On the other hand, the electrochemical performance is strongly dependent on the material properties, requiring sophisticated electrode design with a high active surface area and a large number of redox-active sites. In this study, hierarchically nanoporous pyropolymer nanofibers (HN-PNFs) were fabricated from electrospun polyacrylonitrile nanofibers by simple heating with KOH. The HN-PNFs have a hierarchically nanoporous structure and an exceptionally high specific surface area of 3,950.7m<SUP>2</SUP> g<SUP>−1</SUP> as well as numerous redox-active heteroatoms (C/O and C/N ratio of 10.6 and 16.8, respectively). These unique material properties of HN-PNFs resulted in high reversible Na-ion capacity of ∼292mAhg<SUP>−1</SUP> as well as rapid kinetics and stable cycling performance in the cathodic potential range (1-4.5V vs. Na<SUP>+</SUP>/Na). Furthermore, energy storage devices based on HN-PNFs showed a remarkably high specific energy of ∼258 Wh kg<SUP>−1</SUP> at ∼245Wkg<SUP>−1</SUP> as well as a high specific power of ∼21,500Wkg<SUP>−1</SUP> at ∼78 Wh kg<SUP>−1</SUP>, with long and stable cycling behaviors over 2,000 cycles.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hierarchically nanoporous pyropolymer nanofibers (HN-PNFs) were fabricated. </LI> <LI> HN-PNFs have a high specific surface area of ∼3,950m<SUP>2</SUP> g<SUP>−1</SUP> and numerous heteroatoms. </LI> <LI> HN-PNFs exhibit high capacities of ∼292mAhg<SUP>−1</SUP> and great rate/cycling performances. </LI> <LI> High energy (258Whkg<SUP>−1</SUP>) and high power (21,500Wkg<SUP>−1</SUP>) are achieved. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Hierarchically nanoporous pyropolymer nanofibers (HN-PNFs) fabricated from electrospun polyacrylonitrile nanofibers by simple heating with KOH exhibited high electrochemical performance for Na-ion storage.</P> <P>[DISPLAY OMISSION]</P>

한국인 직무 스트레스 측정도구의 개발 및 표준화

장세진,고상백,강동묵,김성아,강명근,이철갑,정진주,조정진,손미아,채창호,김정원,김정일,김형수,노상철,박재범,우종민,김수영,김정연,하미나,박정선,이경용,김형렬,공정옥,김인아,김정수,박준호,현숙정,손동국 大韓産業醫學會 2005 대한직업환경의학회지 Vol.17 No.4

Background and Purposes: Over the past three decades, numerous studies performed in Korea have reported that job stress is a determinant risk factor for chronic diseases and work disability. Every society has its own culture and occupational climate particular to their organizations, and hence experiences different occupational stress. An occupational stress measurement tool therefore needs to be developed to estimate it objectively. The purpose of this study is to develop and standardize the Korean Occupational Stress Scale (KOSS) which is considered to be unique and specific occupational stressors in Korean employees. Subjects and Methods: Data were obtained from the National Study for Development and Standardization of Occupational Stress (NSDSOS Project: 2002-2004). A total of 12,631 employees from a nationwide sample proportional to the Korean Standard Industrial Classification and the Korean Standard Occupational Classification were administered. The KOSS was developed for 2 years (2002-2004). In the first year, we collected 255 items from the most popular job stress measurement tools such as JCQ, ERI, NIOSH and OSI, and 44 items derived from the a qualitative study (depth interview). Forty-three items of KOSS, in the second year, were retained for use in the final version of the KOSS by using Delphi and factor analysis. Items were scored using conventional 1-2-3-4 Likert scores for the response categories. Results: We developed eight subscales by using factor analysis and validation process: physical environment (3 items), job demand (8 items), insufficient job control (5 items), interpersonal conflict (4 items), job insecurity (6 items), organizational system (7 items), lack of reward (6 items), and occupational climate (4 items). Together they explained 50.0% of total variance. Internal consistency alpha scores were ranged from 0.51 to 0.82. Twenty-four items of the short form of the KOSS (KOSS-SF) were also developed to estimate job stress in the work setting. Because the levels of the subscales of occupational stress were gender dependent, gender-specific standard norms for both the 43-item full version and the 24-item short form using a quartile for the subscales of KOSS were presented. Conclusion: The results of this study suggest that KOSS might be an appropriate measurement scale to estimate occupational stress of Korean employees. Further and more detailed study needs to be conducted to improve the validity of this scale.

A case of cutaneous marginal zone lymphoma with coexistence of T-cell-rich angiomatoid polypoid pseudolymphoma on the face of a Korean girl

( Hyoung Min Na ),( Chang Jin Jung ),( Joon Min Jung ),( Woo Jin Lee ),( Chong Hyun Won ),( Sung Eun Chang ),( Mi Woo Lee ) 대한피부과학회 2021 대한피부과학회 학술발표대회집 Vol.72 No.2

Primary cutaneous marginal zone lymphoma is an indolent B-cell lymphoma of the skin, occasionally showing significant T-cell infiltration with some extent of cytologic atypia. However, as there have been several reports of progression of T-cell lymphoma within the background of primary cutaneous marginal zone lymphoma, it is important to clarify whether the T-cell infiltrates present in T-cell-rich primary cutaneous marginal zone lymphoma are malignant or not. We report a case of cutaneous marginal zone lymphoma with the coexistence of T-cell-rich angiomatoid polypoid pseudolymphoma on the face of a Korean girl.

회화유형에 따른 동양적 이상향(理想鄕)의 성격

나형민(Na, Hyoung-Min) 동서미술문화학회 2020 미술문화연구 Vol.17 No.17

본 논문은 동양회화에서 이상향이 반영되고 표현된 대표적 유형을 <무릉도원도(武陵桃源圖)>, <무이구곡도(武夷九曲圖)>, <태평성시도(太平城市圖)>로 선정하고 각각의 유형에 내재한 동양적 이상향의 성격을 ‘무위자연’, ‘은일도학’, ‘태평성대’로 규정하며 상호 비교분석하는 데 의의가 있다. 이상향을 반영한 회화작품은 인간이 꿈꾸어 왔던 낙원에 대한 소망과 철학을 시각화했으며, 이상향이 갖는 부재와 허구의 한계를 극복하고 생명력을 불어넣은 중요한 매체로서 역할을 해왔다. 따라서 이상향이 반영된 동양화 분석을 통해 서양적 이상향과의 차별화 및 동양인이 생각하는 이상적인 사회와 공간, 철학 등을 포괄하는 동양적 이상향의 원형을 파악하고자 한다. 기존의 동양회화 속에 나타난 이상향 연구는 일편적인 사상 관점에서 조형적 특징이나 연대기적인 양식의 변천 과정에 중점을 두었기에 그 안에 함의된 동양적 이상향의 종합적 속성을 간과하기 쉬웠다. 이에 본고에서는 개별적 작품 분석이나 전개 과정보다 이상향 작품에 내재한 동양적 이상향은 무엇인가 하는 개념과 특성에 관한 철학 전반을 선분석한다. 그리고 각 유형별 대표작의 예시를 통해 의미를 재확인하고 상호 비교하는 방식으로 동양적 이상향을 설명한다. 이러한 방식을 취한 이유는 동양화에 나타난 이상향의 그림은 가공의 이상적 세계를 구체적으로 설명하기보다 문학적이고 서사적이며 은유적인 방식으로 이상향을 형상화하고 있기 때문이다. 따라서 외형의 조형적 특성보다 작품에 내재한 이상향의 의미와 담론을 먼저 조명하는 것이 동양인이 가지고 있는 이상향의 원형에 대한 입체적인 이해를 가능하게 하며, 아울러 이상향 작품의 의의와 특성을 파악하는데 용이하다고 생각한다. This paper aims to conduct a comparative analysis on the paintings of <Painting of the Land of Peach Blossoms>, <Painting of the Nine-Bend Stream of Wuyi Mountains> and <Painting of City of Supreme Peace>, which are representative of expressions of the concepts of Utopia in Northeast Asian Paintings; the characteristic of each painting is defined as ‘natural inaction’, ‘reclusion and Tao learning’, ‘a reign of peace’. Paintings which reflect utopias visualize one’s wishes and philosophies of the paradise one dreams of and play an important role as a medium which puts life into utopia by overcoming the limitation of its absence as an imaginary fiction. Therefore this paper investigates the Asian prototype of utopia by analyzing those three utopian paintings, which differentiates it from Western models of utopias. The previous studies on utopias in Asian Painting tended to focus on its formative characteristics or changes of chronological styles of the paintings from a single point of view, thus the comprehensive attribute of Asian utopias have been easily overlooked. Therefore, this paper comparatively analyzes overall concepts and characteristics of utopias in those three paintings rather than individual analysis or development processes of the paintings. In addition, this paper reinterprets the meaning of utopias by using comparative analysis through the examples of three major utopian paintings. This research methodology is used because Asian utopian paintings visualize utopia by means of literary, descriptive and metaphoric forms rather than formally depicting the ideal world in details. As a result, this paper argues that the meaning and discussions of utopia, immanent to the utopian paintings, should be preferentially investigated prior to formative external characteristics of the paintings; thus it makes it possible to understand the prototypes of the Asian styles of utopias in depth and also is easier to identify the meanings and characteristics of the utopian paintings.

OB-22 : Single institute experience, success rate and obstetric outcomes after external cephalic version at term

( Min Young Park ),( Sun Hwa Lim ),( Mi Na Byon ),( Hye Young Han ),( Mi Young Kim ),( Jin Hwa Jung ),( Sang Hun Lee ),( Dong Ho Kim ),( Hyoung Moo Park ),( Gwang Jun Kim ) 대한산부인과학회 2012 대한산부인과학회 학술대회 Vol.99 No.-

To determine obstetric outcomes after external cephalic version (ECV) performed at term. In a retrospective study of ECV among term breech presentation singleton pregnant women at Chung-Ang Univerisity Hospial between November 2009 and July 2013, we evaluate the mode of delivery after ECV procedure and analyze factors influencing success and complication using for Mann-Whitney test. All contraindication of ECV ( placenta previa, uterine malformation, intrauterine growth retardation with pathologic Doppler and Multiples) Among 96 EVC attempts, 67.4% of women had cephalic presentation (n=64) and 32.6% (n = 31) remained breech presentation. Vaginal delivery was observed by 40 out of 64 (62.5%) among successful ECV , whereas 11 (17.2%) had in-labour Caserean sections. After unsuccessful ECV 31 patients had elective Caserean sections. When comparing the successful and unsuccessful ECV groups, there is a statistical significant difference in position (p=0.013), count of attemps (p=0.001), use of Yutopar (p=0.001). These groups did not show a significant difference in parity, AFI, BMI, newborn weight and newborn gender. In successful ECV group, there is statistical significant difference between vaginal delivery and Caserean sections of parity, engagement. On the same day after the ECV procedure two patients, who had unsuccessful ECVs, had Caesarean sections. One was due to pathological cardiotocogram with no clinical correlation. The other Caesarean section was due to progressed labor. No harm to fetal or maternal health resulted from ECV. ECV was found to be a safe procedure at term. The rate of surgical delivery after successful ECV was low. A trial of ECV at term and beyond is feasible.

Waste coffee grounds-derived nanoporous carbon nanosheets for supercapacitors

Min Hong Park,Young Soo Yun,Se Youn Cho,Na Rae Kim,Hyoung-Joon Jin 한국탄소학회 2016 Carbon Letters Vol.19 No.-

The development of nanostructured functional materials derived from biomass and/or waste is of growing importance for creating sustainable energy-storage systems. In this study, nanoporous carbonaceous materials containing numerous heteroatoms were fabricated from waste coffee grounds using a top-down process via simple heating with KOH. The nanoporous carbon nanosheets exhibited notable material properties such as high specific surface area (1960.1 m2 g–1), numerous redox-active heteroatoms (16.1 at% oxygen, 2.7 at% nitrogen, and 1.6 at% sulfur), and high aspect ratios (>100). These unique properties led to good electrochemical performance as supercapacitor electrodes. A specific capacitance of ~438.5 F g–1 was achieved at a scan rate of 2 mV s–1, and a capacitance of 176 F g–1 was maintained at a fast scan rate of 100 mV s–1. Furthermore, cyclic stability was achieved for over 2000 cycles.

Capacitive charge storage based on nanoporous pyropolymer nanosheets fabricated from natural resources

Na Rae Kim,Min EuiLee,Hyeon Ji Yoon,Hong Joo An,Jun Ho Choe,Young Soo Yun,Hyoung-Joon Jin 한국고분자학회 2016 한국고분자학회 학술대회 연구논문 초록집 Vol.41 No.2

Risk Factors for the Development and Progression of Atlantoaxial Subluxation in Surgically Treated Rheumatoid Arthritis Patients, Considering the Time Interval between Rheumatoid Arthritis Diagnosis and Surgery

Na, Min-Kyun,Chun, Hyoung-Joon,Bak, Koang-Hum,Yi, Hyeong-Joong,Ryu, Je Il,Han, Myung-Hoon The Korean Neurosurgical Society 2016 Journal of Korean neurosurgical society Vol.59 No.6

Objective : Rheumatoid arthritis (RA) is a systemic disease that can affect the cervical spine, especially the atlantoaxial region. The present study evaluated the risk factors for atlantoaxial subluxation (AAS) development and progression in patients who have undergone surgical treatment. Methods : We retrospectively analyzed the data of 62 patients with RA and surgically treated AAS between 2002 and 2015. Additionally, we identified 62 patients as controls using propensity score matching of sex and age among 12667 RA patients from a rheumatology registry between 2007 and 2015. We extracted patient data, including sex, age at diagnosis, age at surgery, disease duration, radiographic hand joint changes, and history of methotrexate use, and laboratory data, including presence of rheumatoid factor and the C-reactive protein (CRP) level. Results : The mean patient age at diagnosis was 38.0 years. The mean time interval between RA diagnosis and AAS surgery was $13.6{\pm}7.0$ years. The risk factors for surgically treated AAS development were the serum CRP level (p=0.005) and radiographic hand joint erosion (p=0.009). The risk factors for AAS progression were a short time interval between RA diagnosis and radiographic hand joint erosion (p<0.001) and young age at RA diagnosis (p=0.04). Conclusion : The CRP level at RA diagnosis and a short time interval between RA diagnosis and radiographic hand joint erosion might be risk factors for surgically treated AAS development in RA patients. Additionally, a short time interval between RA diagnosis and radiographic hand joint erosion and young age at RA diagnosis might be risk factors for AAS progression.

OB-21 : Frontal lobe and cerebellar differences in IUGR and AGA fetuses

( Min Young Park ),( Kyung Won Shim ),( Ju Won Baek ),( Hyun Ji Kim ),( Sun Hwa Im ),( Mi Young Kim ),( Mi Na Byon ),( Eun Ju Lee,),( Seung Su Han ),( Sang Hoon Lee ),( Dong Ho Kim ),( Hyoung Moo Park 대한산부인과학회 2014 대한산부인과학회 학술대회 Vol.100 No.-

목적: Children with history of intrauterine growth restriction (IUGR) have shown abnormal neurological tests or cognitive functions. The pathophysiologic event in utero is not known. Uneven preferential intracranial blood supply can be related. We tried to find the causative phenomenon in fetal brain of severe IUGR. 방법: A prospective ultrasound evaluation of 100 pregnant women was conducted between 18 to 38weeks` gestation between 25 April 2013 and 1 July 2013 in Chung-Ang University Hospital. A group of 7 severe IUGR (defined as an estimated fetal weight <3th centile) , 6 IUGR (estimated fetal weight <10th centile) and 87 AGA fetuses by gestational age were studied. Ultrasound examination for fetal standard fetal biometry, including biparietal diameter (BPD), head circumference(HC), abdominal circumference (AC), femur length, the frontal lobe distance (posterior cavum septum pellucidum to the inner calvarium) and transcerebellar diameter (TCD) were measured in patients. All pregnancies had certain dates. Ratio between frontal lobe distance and TCD were calculated. Differences in ratios between IUGR and AGA fetuses were analyzed Student T-test. 결과: Significant differences (p<0.03) were found in the frontal lobe diameter/ TCD ratio between severe IUGR (0.54) and AGA fetuses (0.62). According to severity of IUGR, frontal lobe diameter showed significant differences (p<0.05). Severe IUGR fetuses (1.4cm) had smaller frontal lobe diameter than IUGR fetuses (1.7cm). However, statistically significant differences of TCD could not found among three groups . 결론: This study shown that in early onset IUGR fetuses, frontal lobe diameter was reduced, but cerebellar diameter was preserved. Under restricted blood supply such as in severe IUGR, growth of frontal lobe is sacrificed first than cerebellar growth. Sonographic measurement of frontal lobe and cerebellar diameter of IUGR fetuses might be useful tool to screen out future neurologic development after birth.