Performance Analysis of a Toroid-Type HTS SMES Adopted for Frequency Stabilization

A-Rong Kim,Sang-Yong Kim,Kwang-Min Kim,Jin-Geun Kim,Seokho Kim,Minwon Park,In-Keun Yu,Sangjin Lee,Myung-Hwan Sohn,Hae-Jong Kim,Joon-Han Bae,Ki-Chul Seong IEEE 2011 IEEE transactions on applied superconductivity Vol.21 No.3

<P>Superconducting magnetic energy storage (SMES) can overcome fluctuations in frequency because of its fast response time in charging and discharging energy. To stabilize the fluctuations in frequency of wind power generation systems (WPGSs), HTS SMES systems should be connected to the terminal of the WPGSs. Ulleung Island's power network in Korea was modeled with a real-time digital simulator (RTDS) to demonstrate the effectiveness of SMES at stabilizing frequency. A toroid-type HTS SMES cooled by conduction cooling and a DC/DC chopper to charge and discharge current were fabricated for the experiment. The simulation results show the frequency stabilization effected by the HTS SMES system with its operational characteristics such as real time variation in current and temperature.</P>

Lack of Dream-Capital among Korean Youths

Seokho Kim,Hongjung Kim,Sangkyu Lee,Eunji Kim,Ohjae Gowen 서울대학교 사회발전연구소 2018 Journal of Asian Sociology Vol.47 No.3

This paper attempts to provide empirical evidence in understanding the ways that contemporary youth pursue their dreams in Korea. This paper examines the rational aspect of “dreaming” or “non-dreaming” by employing two concepts: dream-capital and penetration. In this paper, dream-capital is conceptualized as a seed that facilitates the accumulation of other capitals. It is the total capacity to dream and is composed of four dimensions: imagination, hope, optimism and resilience. Penetration is defined as the “cognitive judgment about the (un)realizability of dream.” It refers to the discrepancy that exists between judgment about the capacity, condition and qualification required to fulfill one’s dream and judgment about the extent to which one thinks she is equipped with that capacity, condition and qualification. Penetration consists of four factors: individual traits, ascribed status, individual qualifications, and national/social conditions. By analyzing the “Korean Youth Values Survey” data, this paper first examines how the general level of dream-capital is influenced by the total penetration score. And then, it also investigates the effects of four types of penetration on four dimensions of dream-capital. The results confirm that dream-capital is strongly affected by penetration. The ability to penetrate insufficient resources in pursuing dreams leads to lowering of dream-capital. Second, penetration on ascribed status and societal factors are found to be important predictors of dream-capital. These results reveal that for youth, the judgment made on their ascribed status rather than judgements made on individual trait or qualification plays a more important role in promoting dream-capital. The results imply that dreams are pursued and formed in close relation to rational cognitions among Korean youth. Korean youth are more likely to have dreams for long-term future when they believe that those dreams can be realized. Dreams are then rationalized fantasies.

Analysis of Operational Loss Characteristics of 10 kJ Class Toroid-Type SMES

Kwangmin Kim,A-Rong Kim,Jin-Geun Kim,Minwon Park,In-Keun Yu,Myung-Hwan Sohn,Bum-Yong Eom,Kidoek Sim,Seokho Kim,Hae-Jong Kim,Joon-Han Bae,Ki-Chul Seong IEEE 2011 IEEE transactions on applied superconductivity Vol.21 No.3

<P>This paper describes the design results, loss analysis, and experiment testing of the real manufactured toroid-type superconducting magnetic energy storage (SMES). We analysed heat load through the conduction and radiation of the cryostat and magnetization loss caused by the charging and discharging of the toroid-type SMES system. We also measured the characteristics of toroid-type SMES under three different types of operating conditions (steady state, one-cycle charging and discharging, series charging and discharging). The fundamental design specifications and the data obtained from the experiment will be applied to a large-scale toroid-type SMES system design.</P>

Operating Characteristics of an Insulationless HTS Magnet Under the Conduction Cooling Condition

Kwangmin Kim,Sung-Jun Jung,Hae-Jin Sung,Gyeong-Hun Kim,Seokho Kim,Sangjin Lee,A-Rong Kim,Minwon Park,In-Keun Yu IEEE 2013 IEEE transactions on applied superconductivity Vol.23 No.3

<P>This paper considers the insulationless high-temperature superconducting (HTS) magnet as a new and innovative concept for dc applications due to its benefits as compared to conventional HTS magnets with insulation layers between HTS conductors. The purpose of this paper is to study the operating characteristics of an insulationless HTS magnet. The normal operating characteristics of the insulationless HTS magnet were investigated according to the various current levels. Thermal stability of the insulationless HTS magnet was also analyzed. The critical current of the insulationless HTS magnet was measured at 40 K. The temperature distribution of the insulationless HTS magnet was measured using thermocouples. The experiment results demonstrate superior thermal stability characteristics in the insulationless HTS magnet. Thus, it is confirmed that the thermal performance of large-scale HTS magnets can be enhanced by applying insulationless magnets instead of general insulated HTS magnets.</P>

한국 청년세대의 꿈-자본 측정

김석호(Seokho Kim),주윤정(YunJeong Joo),성연주(YunJoo Sung),김지애(Jeeae Kim),김은지(EunJi Kim),이상규(Sangkyu Lee),김홍중(HongJung Kim) 한국문화사회학회 2017 문화와 사회 Vol.24 No.-

이 연구는 한국의 청년세대가 미래를 꿈꾸는 방식과 연관된 여러 중요한 내용들을 서베이를 활용하여 측정, 탐구하는 것을 목적으로 한다. 연구의 이론적 바탕에는 꿈-자본의 개념이 있다. 부르디외의 자본 개념을 적극적으로 활용하며, 우리는 행위자가 미래를 상상하는 힘, 희망의 감정을 품는 힘, 낙관적 태도를 견지하는 힘, 그리고 난관을 이겨가는 힘으로 구성된 총체적 능력인 꿈-자본을 형성하여 다른 자본들을 향한 동기로 활용한다는 관점을 취하고, 이를 실증적으로 탐구해 보고자 한다. 또한 청년세대가 꿈을 이루어 가는 경로와 꿈의 내용, 그리고 꿈을 경영하는 방식에 대한 탐구도 시도한다. 이를 통해 이 연구는 한국 청년의 미래 표상에 대한 경험적 탐구를 위한 기초를 마련해 보고자 한다. 꿈-자본 연구는 청년의 이질성을 분석하는데 중요한 실마리를 제공하고 있다. 기초적 분석 결과는 청년세대의 꿈이 이질화되어가고 있다는 것을 보여주고 있으며, 교육수준의 차이가 중요한 역할을 하고 있음을 시사한다. This research explores the various ways in which the young generation in South Korea today dream about their future, using the survey questionnaires specifically designed for this purpose. “Dreamcapital” serves as a theoretical framework in the research. Building on Bourdieu’s concept of capital, this study theorizes that dream-capital functions like a seed, facilitating the accumulation of other capitals. It is composed of four dimensions: imagination, hope, optimism and resilience. Furthermore, this study examines the process of dream formation and management as well as its content. This paper aims to lay the foundations for further research on the dream and values of this young population. The research on dream-capital helps examine the divergence within the young generation. The basic analysis indicates that the ways in which the young population dream about their future vary, and a significant portion of this variation is explained by the difference in the educational attainment.

10 MW급 gearless 타입 초전도 풍력발전기의 개념 설계

김남원(Namwon Kim),김경훈(Gyeong-Hun Kim),김광민(Kwang-Min Kim),김석호(Seokho Kim),박민원(Minwon Park),유인근(In-Keun Yu),이상진(Sangjin Lee) 대한전기학회 2011 대한전기학회 학술대회 논문집 Vol.2011 No.7

Development of a PSCAD/EMTDC Model Component for AC Loss Characteristic Analysis of HTS Power Cable

Jin Geun Kim,A-Rong Kim,Daewon Kim,Minwon Park,In-Keun Yu,Jeonwook Cho,Ki-Deok Sim,Seokho Kim,Jun Kyoung Lee,Young-Jin Won IEEE 2010 IEEE transactions on applied superconductivity Vol.20 No.3

<P>Although Electromagnetic power transient analysis software (PSCAD/EMTDC) is one of the useful simulation tools, it does not provide a High Temperature Superconducting (HTS) power cable component, which has the same impedance characteristic of a real HTS power cable. The authors have already proposed a model component of the HTS power cable under the fault condition and simulated power system including the HTS power cable component. The authors, in this paper, developed a PSCAD/EMTDC model component of the HTS power cable that includes the AC loss characteristic. The AC loss of the superconductor changes due to the magnitude of the transport current. The relational characteristics between the AC transport current and resistance were measured using a model cable. The obtained characteristics were applied to the model component of PSCAD/EMTDC. The developed model component was used in the EMTDC simulation circuit. The simulation results show the same characteristics as the experiment results. The resistance variation of the HTS power cable and AC loss could be simulated using the developed model component and the component will effectively be used for the AC loss related simulations.</P>

액체질소 직접분사 냉각방식 mRNA 백신 극저온 저장용기 제작

김기환(Kihwan kim),문정민(Jeongmin Mun),김한영(Hanyoung Kim),김유빈(Yubin Kim),백정현(Jeonghyeon Baek),김석호(Seokho Kim) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.05

In particular, as the mRNA vaccine becomes a major preventive vaccine in the case of COVID-19, the transportation method is being studied to meet global demand. For example, recently developed as a COVID-19 vaccine, Pfizer vaccines should be stored in the temperature range of -70℃, and similar vaccines should also be stored a -30 ℃ or below. However, existing cold storage systems are too high cost to apply storage systems below -30 ℃ and are difficult to apply in transportation. In this study, storage of direct injection using liquid nitrogen was manufactured and maintaining temperature of demanded target. In addition, vaccine storage containers were designed with considering thermal insulation, manufactured, and performance evaluations were implemented.

Multifunctional π-conjugated poly (3-methylthiophene) nanotubes for optoelectronic and field emissive devices

Hong, Young Ki,Kim, Seokho,Kim, Hyeong Tae,Kim, Sunkook,Kim, Bong-Gi,Lee, Sunjong,Park, Dong Hyuk,Kim, Bo-Hyun Elsevier 2016 ORGANIC ELECTRONICS Vol.32 No.-

<P><B>Abstract</B></P> <P>Multifunctional properties of nanomaterials becomes a hot topic in nano research for the development of multifunctional devices, because modern devices need multifunctional platform for the high efficient plural performance on a single device. Here, we introduce a multifunctional π-conjugated poly (3-methylthiophene) (P3MT) nanotube (NT), showing controllable optical and electrical properties through the control of doping level. P3MT NTs were electrochemically synthesized in the low temperature (−40 °C) on the nanoporous template. The change of doping level by post cyclic voltammetry (CV) treatment on the P3MT lead the variance of polaron/bipolaron band, resulting into the drastic change of ultraviolet-visible absorption and photoluminescence properties. While P3MT NTs before CV treatment show an ohmic behavior in the current-voltage characteristics, those after CV treatment show high photocurrent. From the field emission experiment, the P3MT NTs before CV treatment have a relatively low turn-on electric field and stable electron emission property compared to the P3MT NTs after CV treatment. This shows that the π-conjugated polymers should be shed new light on their multifunctionality for the potential application to the multifunctional platform of opto-electronic nanodevices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Poly (3-methylthiophene) (P3MT) nanotubes (NTs) are successfully fabricated. </LI> <LI> Photoluminescence and photocurrent of the P3MT NTs are controlled in terms of doping level. </LI> <LI> Doped P3MT NTs exhibit superb and stable field emission properties. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

An Antibody Designed to Improve Adoptive NK-Cell Therapy Inhibits Pancreatic Cancer Progression in a Murine Model

Lee, Jaemin,Kang, Tae Heung,Yoo, Wonbeak,Choi, Hyunji,Jo, Seongyea,Kong, Kyungsu,Lee, Sang-Rae,Kim, Sun-Uk,Kim, Ji-Su,Cho, Duck,Kim, Janghwan,Kim, Jeong-Yoon,Kwon, Eun-Soo,Kim, Seokho AMERICAN ASSOCIATION FOR CANCER RESEARCH 2019 CANCER IMMUNOLOGY RESEARCH Vol.7 No.2

<P>The homing of natural killer (NK) cells is often inhibited by pancreatic cancer tumors. A mesothelin-directed antibody conjugated to a cleavable NK cell—recruiting chemokine increased NK-cell infiltration of PDAC tumors, reduced tumor burden, and improved survival.</P><P>Natural killer (NK) cells are primary immune cells that target cancer cells and can be used as a therapeutic agent against pancreatic cancer. Despite the usefulness of NK cells, NK-cell therapy is limited by tumor cell inhibition of NK-cell homing to tumor sites, thereby preventing a sustained antitumor immune response. One approach to successful cancer immunotherapy is to increase trafficking of NK cells to tumor tissues. Here, we developed an antibody-based NK-cell–homing protein, named NK-cell–recruiting protein-conjugated antibody (NRP-body). The effect of NRP-body on infiltration of NK cells into primary and metastatic pancreatic cancer was evaluated <I>in vitro</I> and in murine pancreatic ductal adenocarcinoma models. The NRP-body increased NK-cell infiltration of tumors along a CXCL16 gradient (CXCL16 is cleaved from the NRP-body by furin expressed on the surface of pancreatic cancer cells). CXCL16 induced NK-cell infiltration by activating RhoA via the ERK signaling cascade. Administration of the NRP-body to pancreatic cancer model mice increased tumor tissue infiltration of transferred NK cells and reduced the tumor burden compared with that in controls. Overall survival of NRP-body–treated mice (even the metastasis models) was higher than that of mice receiving NK cells alone. In conclusion, increasing NK-cell infiltration into tumor tissues improved response to this cancer immunotherapy. The combination of an NRP-body with NK-cell therapy might be useful for treating pancreatic cancer.</P>