Resistive switching behaviors of Ti nano-layer embedded TaO_x-based devices

Jeon, Heeyoung,Park, Jingyu,Jang, Woochool,Kim, Hyunjung,Lee, Kunyoung,Shin, Changhee,Lee, Jaemin,Jeon, Hyeongtag ELSEVIER 2017 CURRENT APPLIED PHYSICS Vol.17 No.2

<P>The role of a Ti nano-layer embedded in TaOx-based devices operating with conductive filaments consisting of oxygen vacancies was investigated. The Ti nano-layer was embedded in three different positions: the top interface (Au/TaOx), bottom interface (TaOx/TiN), and both interfaces. The embedded Ti nano-layer serves as not only an oxygen reservoir but also a tunneling barrier in the case of the top interface. The position of the Ti nano-layer and its thickness play important roles in the resistive switching behaviors. In addition, the effect of the current compliance on the resistive switching behaviors was evaluated. The different resistive switching behaviors were investigated using current voltage sweep measurements and X-ray photoelectron spectroscopy. The non-linear behavior of the low resistance state could be controlled by the top interface and current compliance. The current of the high resistance state could be controlled by the bottom interface. It is noteworthy that only 1.5-nm-thick Ti nano-layer can adjust the non-linear behavior of the low resistance state at top interface and the current of the high resistance state at bottom interface. (C) 2016 Elsevier B.V. All rights reserved.</P>

지역아동센터 이용 아동의 부모-자녀 의사소통 시간이 학교적응에 미치는 영향

전재민(Jaemin Jeon),이규호(Kyuho Lee) 한국문화융합학회 2023 문화와 융합 Vol.45 No.10

본 연구는 지역아동센터 이용 아동의 부모-자녀 의사소통이 학교적응에 미치는 영향에서 사회적 위축매개효과를 검증하는 데 목적이 있다. 이에 한국청소년연구원에서 보건복지부와 지역아동센터 중앙지원단의 위탁을 받아 수집한 지역아동센터 아동패널조사 3기 패널데이터 3차년도(2020)의 초등학교 6학년자료를 사용하여 회귀분석과 매개효과분석 모형을 검증하였다. 연구결과 첫째, 지역아동센터 이용 아동의 부모-자녀 의사소통 시간이 학교적응과 정적인 관계가 있는 것으로 나타났다. 둘째, 지역아동센터아동의 부모-자녀 의사소통과 학교적응의 관계에서 사회적 위축이 유의미한 매개효과를 미치는 것으로나타났다. 부모-자녀 의사소통이 사회적 위축을, 다시 사회적 위축이 학교적응에 부적인 영향을 미치는것으로 볼 수 있다. 이러한 결과를 바탕으로 긍정적인 의사소통을 위한 부모교육이 자녀의 학교 적응문제 극복에 갖는 영향에 대해 논의한다. The purpose of this study is to test the mediating effect of social atrophy on the effect of parent-child communication on school adjustment among children using local children's centers. For this purpose, regression and mediation analysis models were tested using data from the 6th grade of the 3rd panel data year (2020) of the Regional Children's Center Child Panel Survey. The results showed that parent-child communication time was positively related to school adjustment among children using community children's centers, and social withdrawal had a significant mediating effect on the relationship between school adjustment and parent-child communication. Based on these results, it is suggested that parental education for positive communication can help children overcome school adjustment problems.

조음 장애인들의 음성인식을 위한 AI 어플리케이션

전재민(Jaemin Jeon),이혁(Hyuk Lee),황성수(Sungsoo Hwang) 한국정보과학회 2019 한국정보과학회 학술발표논문집 Vol.2019 No.6

BTS: 한국어 BERT를 사용한 텍스트 세그멘테이션

전재민(Jaemin Jeon),최우용(Wooyong Choi),최수정(Su Jeong Choi),박세영(Seyoung Park) 한국정보과학회 2019 한국정보과학회 학술발표논문집 Vol.2019 No.12

Efficient Inorganic–Organic Hybrid Perovskite Solar Cells Based on Pyrene Arylamine Derivatives as Hole-Transporting Materials

Jeon, Nam Joong,Lee, Jaemin,Noh, Jun Hong,Nazeeruddin, Mohammad Khaja,Grä,tzel, Michael,Seok, Sang Il American Chemical Society 2013 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.135 No.51

<P>A set of three <I>N</I>,<I>N</I>-di-<I>p</I>-methoxyphenylamine-substituted pyrene derivatives have successfully been synthesized and characterized by <SUP>1</SUP>H/<SUP>13</SUP>C NMR spectroscopy, mass spectrometry, and elemental analysis. The optical and electronic structures of the pyrene derivatives were adjusted by controlling the ratio of <I>N</I>,<I>N</I>-di-<I>p</I>-methoxyphenylamine to pyrene, and investigated by UV/vis spectroscopy and cyclic voltammetry. The pyrene derivatives were employed as hole-transporting materials (HTMs) in fabricating mesoporous TiO<SUB>2</SUB>/CH<SUB>3</SUB>NH<SUB>3</SUB>PbI<SUB>3</SUB>/HTMs/Au solar cells. The pyrene-based derivative Py-C exhibited a short-circuit current density of 20.2 mA/cm<SUP>2</SUP>, an open-circuit voltage (<I>V</I><SUB>oc</SUB>) of 0.886 V, and a fill factor of 69.4% under an illumination of 1 sun (100 mW/cm<SUP>2</SUP>), resulting in an overall power conversion efficiency of 12.4%. The performance is comparable to that of the well-studied spiro-OMeTAD, even though the <I>V</I><SUB>oc</SUB> is slightly lower. Thus, this newly synthesized pyrene derivative holds promise as a HTM for highly efficient perovskite-based solar cells.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2013/jacsat.2013.135.issue-51/ja410659k/production/images/medium/ja-2013-10659k_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja410659k'>ACS Electronic Supporting Info</A></P>

Silyl Substituted Methanofullerenes as Electron Acceptors in Organic Photovoltaic Cells

Jeon, Mina,Jung, Jaewook,Lee, Jaemin,Lim, Jongsun,Shin, Won Seok,Moon, Sang-Jin,Lee, Changjin,Yoon, Sung Cheol Informa UK (TaylorFrancis) 2010 MOLECULAR CRYSTALS AND LIQUID CRYSTALS - Vol.519 No.1

<i>o</i>-Methoxy Substituents in Spiro-OMeTAD for Efficient Inorganic–Organic Hybrid Perovskite Solar Cells

Jeon, Nam Joong,Lee, Hag Geun,Kim, Young Chan,Seo, Jangwon,Noh, Jun Hong,Lee, Jaemin,Seok, Sang Il American Chemical Society 2014 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.136 No.22

<P>Three spiro-OMeTAD derivatives have been synthesized and characterized by <SUP>1</SUP>H/<SUP>13</SUP>C NMR spectroscopy and mass spectrometry. The optical and electronic properties of the derivatives were modified by changing the positions of the two methoxy substituents in each of the quadrants, as monitored by UV–vis spectroscopy and cyclic voltammetry measurements. The derivatives were employed as hole-transporting materials (HTMs), and their performances were compared for the fabrication of mesoporous TiO<SUB>2</SUB>/CH<SUB>3</SUB>NH<SUB>3</SUB>PbI<SUB>3</SUB>/HTM/Au solar cells. Surprisingly, the cell performance was dependent on the positions of the OMe substituents. The derivative with <I>o</I>-OMe substituents showed highly improved performance by exhibiting a short-circuit current density of 21.2 mA/cm<SUP>2</SUP>, an open-circuit voltage of 1.02 V, and a fill factor of 77.6% under 1 sun illumination (100 mW/cm<SUP>2</SUP>), which resulted in an overall power conversion efficiency (PCE) of 16.7%, compared to ∼15% for conventional <I>p</I>-OMe substituents. The PCE of 16.7% is the highest value reported to date for perovskite-based solar cells with spiro-OMeTAD. </P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2014/jacsat.2014.136.issue-22/ja502824c/production/images/medium/ja-2014-02824c_0004.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja502824c'>ACS Electronic Supporting Info</A></P>

Scalarane Sesterterpenes from the Sponge <i>Hyatella</i> sp.

Jeon, Ju-eun,Bae, Jaemin,Lee, Kyung Jin,Oh, Ki-Bong,Shin, Jongheon American Chemical Society and American Society of 2011 Journal of natural products Vol.74 No.4

<P>Five new sesterterpenes (<B>7</B>−<B>11</B>) along with six known compounds (<B>1</B>−<B>6</B>) were isolated from the sponge <I>Hyatella</I> sp., collected off the coast of Soheuksan-do, Korea. Spectroscopic analyses revealed these compounds as scalarane sesterterpenes with oxidized furan moieties (<B>7</B>−<B>10</B>) and a corresponding lactam (<B>11</B>). The compounds exhibited moderate cytotoxicity, antibacterial activity, and weak inhibitory activity against isocitrate lyase.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jnprdf/2011/jnprdf.2011.74.issue-4/np1006873/production/images/medium/np-2010-006873_0002.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/np1006873'>ACS Electronic Supporting Info</A></P>

enomenological Analysis for Water Exchange in Bentonite Porewater and Suggestion on the Performance Assessment on the Domestic Disposal Facility for High-level Radioactive Waste

Jaemin Jung,Seong-Su Jeon,Sukhoon Kim,Jeong-Hwan Lee,Haeryong Jung 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.1

Bentonite, a material mainly used in buffer and backfill of the engineering barrier system (EBS) that makes up the deep geological repository, is a porous material, thus porewater could be contained in it. The porewater components will be changed through ‘water exchange’ with groundwater as time passes after emplacement of subsystems containing bentonite in the repository. ‘Water exchange’ is a phenomenon in which porewater and groundwater components are exchanged in the process of groundwater inflow into bentonite, which affects swelling property and radionuclide sorption of bentonite. Therefore, it is necessary to assess conformity with the performance target and safety function for bentonite. Accordingly, we reviewed how to handle the ‘water exchange’ phenomenon in the performance assessment conducted as part of the operating license application for the deep geological repository in Finland, and suggested studies and/or data required for the performance assessment of the domestic disposal facility on the basis of the results. In the previous assessment in Finland, after dividing the disposal site into a number of areas, reference and bounding groundwaters were defined considering various parameters by depth and climate change (i.e. phase). Subsequently, after defining reference and bounding porewaters in consideration of water exchange with porewater for each groundwater type, the swelling and radionuclides sorption of bentonite were assessed through analyzing components of the reference porewater. From the Finnish case, it is confirmed that the following are important from the perspective of water exchange: (a) definition of reference porewater, and (b) variations in cation concentration and cation exchange capacity (CEC) in porewater. For applying items above to the domestic disposal facility, the site-specific parameters should be reflected for the following: structure of the bedrock, groundwater composition, and initial components of bentonite selected. In addition, studies on the following should be required for identifying properties of the domestic disposal site: (1) variations in groundwater composition by subsurface depth, (2) variations in groundwater properties by time frame, and (3) investigation on the bedrock structure, and (4) survey on initial composition of porewater in selected bentonite The results of this study are presumed to be directly applied to the design and performance assessment for buffer and backfill materials, which are important components that make up the domestic disposal facility, given the site-specific data.

A study on the photopolymerization of acrylic monomers having fluorene moiety for the application of holographic data storage system.

Jeon, Mina,Yoon, Sung Cheol,Lee, Jaemin,Han, Mijeong,Lee, Changjin American Scientific Publishers 2009 Journal of Nanoscience and Nanotechnology Vol.9 No.12

<P>We have prepared photopolymer compositions for holographic data storage system from aromatic diacrylate having fluorine moiety, a hybrid sol-gel, and photoinitiator. The fluorenyl diacrylate monomer was synthesized via nucleophilic substitution reaction of fluorene diphenol with an excess of 2-chloroethoxyethanol, followed by the reaction with acryloyl chloride. The physical and holographic properties of photopolymer were controlled by the ratio of precursor triethoxysilylpropyl polyethyleneglycol carbamate (TSPEG) in a hybrid sol-gel binder and the content of monomer. Also, we measured the photopolymerization rate and conversion of monomer by photo-differential scanning calorimeter (photo-DSC). Holographic recording was attempted by photopolymerization of the monomers in the photopolymer film using a 532 nm laser light in the presence of Irgacure 784 and holographic gratings were recorded into the photopolymer films by interfering two collimated plane wave beams. Contents of monomer and TSPEG were changed in the range of 0.25-1.0 equiv. and the composition were optimized in terms of diffraction efficiency. Finally, we obtained that efficient photopolymer films showed diffraction efficiency of 78% when 0.5 equiv. of TESPEG in sol-gel binder and 40% of compound 4 were added.</P>