Feasible tuning of barrier energy in PEDOT:PSS/Bi₂Te₃ nanowires-based thermoelectric nanocomposite thin films through polar solvent vapor annealing

Kim, Wan Sik,Anoop, Gopinathan,Jeong, Il-Seok,Lee, Hye Jeong,Kim, Hyun Bin,Kim, Soo Hyeon,Goo, Gi Won,Lee, Hyunmyung,Lee, Hyeon Jun,Kim, Chingu,Lee, Joo-Hyoung,Mun, Bongjin Simon,Park, Ji-Woong,Lee, E Elsevier 2020 Nano energy Vol.67 No.-

<P><B>Abstract</B></P> <P>For next-generation energy harvesting thermoelectric (TE) devices based on organic/inorganic composites, the barrier energy at interfaces of components is critical in determining the TE performances, because the barrier energy can directly enhance Seebeck coefficient (<I>S</I>). We have succeeded in precisely tuning the barrier energy in poly (3,4-ethylene dioxythiophene) polystyrene sulfonate (PEDOT:PSS)/Bi<SUB>2</SUB>Te<SUB>3</SUB> nanowires (NWs) based organic/inorganic nanocomposite films through polar solvent vapor annealing (PSVA). Controlling the PSS/PEDOT ratio as a function of PSVA duration, the work function of PEDOT:PSS was tuned, which eventually varied the barrier energy of nanocomposite thin films. Through optimization of Bi<SUB>2</SUB>Te<SUB>3</SUB>/PEDOT:PSS barrier energy, the <I>S</I> was maximized up to 47 μV/K. The electrical conductivity was also maximized simultaneously, because of the PSVA-induced <I>π-π</I> stacking among PEDOT chains and templating effect. Density functional theory calculated an optimal barrier energy (0.12 eV), which showed an excellent agreement with our experimentally determined optimal barrier energy (0.11 eV), at which we also maximized the power factor—an efficiency indicator of TE performance. Our feasible strategy on the manipulation of barrier energy in PEDOT:PSS/Bi<SUB>2</SUB>Te<SUB>3</SUB> NWs through the PSVA can be extended to other organic/inorganic based TE composites, toward the realization of highly efficient TE devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We tuned the barrier energy of PEDOT:PSS/Bi<SUB>2</SUB>Te<SUB>3</SUB> nanowires through simply varying the PSVA duration. </LI> <LI> Simultaneous enhancement of Seebeck and electrical conductivity is achieved by optimizing the barrier energy. </LI> <LI> We achieved a power factor maximum of 223 μW/mK<SUP>2</SUP> when the barrier energy, Δ<I>E</I>=0.11 eV, at PSVA duration for 120 min. </LI> <LI> The optimized barrier energy for the enhanced Seebeck coefficient agrees well with the DFT calculated Δ<I>E</I> of 0.12 eV. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Aryl biphenyl-3-ylmethylpiperazines as 5-HT7 receptor antagonists.

Kim, Jeeyeon,Kim, Youngjae,Tae, Jinsung,Yeom, Miyoung,Moon, Bongjin,Huang, Xi-Ping,Roth, Bryan L,Lee, Kangho,Rhim, Hyewhon,Choo, Il Han,Chong, Youhoon,Keum, Gyochang,Nam, Ghilsoo,Choo, Hyunah Wiley-VCH 2013 ChemMedChem Vol.8 No.11

<P>The 5-HT7 receptor (5-HT7 R) is a promising therapeutic target for the treatment of depression and neuropathic pain. The 5-HT7 R antagonist SB-269970 exhibited antidepressant-like activity, whereas systemic administration of the 5-HT7 R agonist AS-19 significantly inhibited mechanical hypersensitivity and thermal hyperalgesia. In our efforts to discover selective 5-HT7 R antagonists or agonists, aryl biphenyl-3-ylmethylpiperazines were designed, synthesized, and biologically evaluated against the 5-HT7 R. Among the synthesized compounds, 1-([2'-methoxy-(1,1'-biphenyl)-3-yl]methyl)-4-(2-methoxyphenyl)piperazine (28) was the best binder to the 5-HT7 R (pKi =7.83), and its antagonistic property was confirmed by functional assays. The selectivity profile of compound 28 was also recorded for the 5-HT7 R over other serotonin receptor subtypes, such as 5-HT1 R, 5-HT2 R, 5-HT3 R, and 5-HT6 R. In a molecular modeling study, the 2-methoxyphenyl moiety attached to the piperazine ring of compound 28 was proposed to be essential for the antagonistic function.</P>

Exploring How Upper Echelons Adapt Strategies and Compensation Mechanisms within the High Discretionary Context

Bongjin Kim(김봉진) 대한경영학회 2018 大韓經營學會誌 Vol.31 No.10

Low-Complexity Parallel QPP Interleaver Based on Permutation Patterns

Bongjin Kim,Injae Yoo,In-Cheol Park IEEE 2013 IEEE transactions on circuits and systems. a publi Vol.60 No.3

<P>In this brief, we present how parallel-interleaved addresses generated by a quadratic permutation polynomial (QPP) interleaver are related to each other and propose a low-complexity parallel QPP interleaver based on the relationship. While a conventional parallel turbo decoder employs a number of interleavers as many as the parallel factor, the proposed method, which benefits from the arithmetic relationship denoted as the permutation pattern (PP), supports the parallel interleaving using only a single interleaver, resulting in a notable reduction of complexity. The strength of the proposed method stems from the fact that the PP is fully determined by only the decoding parameters, such as block size, parallel factor, and QPP coefficients. Experiment results on the Long Term Evolution turbo codes show that the proposed interleaver can significantly reduce the hardware complexity compared with conventional implementations.</P>

THE PARADOX OF BOARD STRUCTURE CHANGE

Bongjin Kim 한국전략경영학회 2012 전략경영연구 Vol.15 No.2

본 연구는 대리인 이론과 집사 이론에 기반하여 산업 내 규제완화 시 기업이 선택하는 이사회의 구조적인 변화를 검토하고 기업이 채택한 이사회의 구조적 특성이 기업성과에 미치는 영향을 고찰 하였다. 구체적으로 본 연구는 1980년대의 미국 금융 산업의 탈규제 기간 동안에 미국의 은행들을 대상으로 분석한 결과 다소 모순된 결과가 입증되었다. 1981-1992 기간 동안 은행들은 최고경영자와 이사회 의장의 겸직을 증가시키고 이사회의 규모를 축소하는 현상을 보였다. 이러한 변화는 새로운 경쟁환경 하에서 최고 경영자의 자유재량과 권한위임의 중요성을 강조하는 집사이론에 기반하여 설명될 수 있다. 그러나 같은 기간 동안 좋은 성과를 낸 은행들은 아이러니컬하게도 최고경영자와 이사회 의장을 분리한 경우와 큰 규모의 이사회를 가진 은행들이었음이 확인 되었다. 이러한 결과는 불확실한 경쟁환경 하에서 대리인문제의 통제를 강조하는 대리인이론에 기반하여 이해될 수 있다. 더 나아가 이러한 이사회의 구조적 특성과 기업 성과와의 관계는 이사회 구성원들의 소유지분에 따라 조절되는 현상이 입증 되었다. 따라서 본 연구는 기존의 이사회구조와 기업성과의 혼재된 연구결과에 새로운 방향과 설명력을 제시하였다는 점에 그 의의가 있다고 본다. Drawing on both agency and stewardship theories, we examine the changes made to board structures in response to deregulation and the consequences of those observed changes on firm performance. We test the hypotheses using longitudinal data from the U.S. banking industry over the period 1981-1992, a noted era of deregulation. The results yield rather paradoxical outcomes. Changes in board structures appear to follow stewardship theory logic but firm performance is better among banks that appear to rely on agency theory logic. Finally, the results indicate that board equity ownership moderates the relationship between board structures and firm performance within the context of deregulation.

Nanoporous Bicontinuous Structures via Addition of Thermally-Stable Amphiphilic Nanoparticles within Block Copolymer Templates

Kim, Seyong,Yoo, Misang,Kang, Nana,Moon, Bongjin,Kim, Bumjoon J.,Choi, Soo-Hyung,Kim, Jaeup U.,Bang, Joona American Chemical Society 2013 ACS APPLIED MATERIALS & INTERFACES Vol.5 No.12

<P>Herein, we fabricated the bicontinuous structures from nanocomposites of poly(styrene-<I>b</I>-methyl methacrylate) (PS-<I>b</I>-PMMA) block copolymer and the shell-cross-linked, thermally stable gold nanoparticles (Au NPs). The surface property of Au NPs was controlled with ligands containing various compositions of PS and PMMA so that the resulting Au NPs were selective to PS or PMMA block or nonselective (i.e., neutral) to both blocks. The amphiphilic Au NPs were also prepared by coating the surface of Au NPs with equimolar mixtures of PS and PMMA selective ligands. Consequently, it was found that the morphological behaviors of thermally annealed nanocomposites containing amphiphilic Au NPs and PS-<I>b</I>-PMMA were dramatically different from the case of neutral Au NPs that were coated with nonselective ligands. With increasing the amount of amphiphilic Au NPs, a transition from lamellar to bicontinuous structures was observed, whereas the neutral Au NPs were aggregated within the PS-<I>b</I>-PMMA lamellae. Furthermore, the nanoporous bicontinuous thin films were fabricated on the silicon substrates and the morphological behaviors were quantitatively investigated by grazing-incidence small-angle X-ray scattering (GISAXS) analysis.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2013/aamick.2013.5.issue-12/am400999z/production/images/medium/am-2013-00999z_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am400999z'>ACS Electronic Supporting Info</A></P>

동아시아 ‘근세’의 ‘유교적 근대’와 ‘병학적 근대’

김봉진 ( Kim Bongjin ) 퇴계학부산연구원 2018 退溪學論叢 Vol.32 No.-

‘근세’란 나이토 코난(內藤湖南)이 만든 용어이다. 이로써 그는 중국 ‘근세’론을 제기 했다. 이를 통해 중국 ‘근세’의 구성 요소를 추출할 수 있다. 그런데 기시모토 미오(岸本美緖)는 중국 ‘근세’론의 변종인 동아시아 ‘근세’론을 전개했다. 그러나 이때 중국 ‘근 세’론의 틀은 거의 형체를 잃을 만큼 변질된다. 이러한 변질은 중국 ‘근세’와 일본 ‘근 세’의 정합성 여부 라는 문제로 이어진다. 그 답은 ‘거의 없음’이다. 한편 미야지마 히 로시(宮嶋博史)는 동아시아 ‘유교적 근대’론을 제안한다. 필자는 그 의의와 문제점을 검 토한다. 이와 함께 ‘유교적 근 대’론을 일본/사에는 적용하기 어렵다는 한계를 지적한다. 오히려 일본의 ‘병학적 근대’론을 그 대안으로 제기하고자 한다. The term ‘early modern (period)’ was coined by Naito Konan(內藤湖南). By this, he suggested the theory of Chinese ‘early modern (period).’ From his theory, we may extract the constitutive elements of Chinese ‘early modern (period).’ By the way, Kishimoto Mio(岸本美緖) developed the theory of East Asian ‘early modern (period).’ At this time, however, the Chinese ‘early modern (period)’ has deteriorated in its frame, almost lost its shape. This entails a question whether there is any coordination between the Chinese and Japanese ‘early modern (period)’ or not. The answer is ‘there is none for the most part.’ As contrasted with this, Miyazima Hiroshi(宮嶋博史) proposed the theory of the ‘Confucian modern.’ I will examine its significance as well as problems. And I will indicate, it is hard to apply that theoy to Japan or the Japanese history. On the contrary, I would rather suggest the theory of the Japanese ‘military science modern’ as an alternative.

HEMC의 치환도에 따른 압출성형 시멘트패널의 경화 거동과 압출속도

김태헌(Kim, Taeheon),권봉진(Kwon, Bongjin),김두호(Kim, Dooho),최낙운(Choi, Nakwoon) 대한건축학회 2015 대한건축학회 학술발표대회 논문집 Vol.2015 No.-

저자유도 기구를 이용한 반복 공간 운동 재현을 위한 1자유도 기구설계

김봉진(Bongjin Kim),최용제 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5

Femtosecond Terahertz measurement of ionic liquid electrochemical cell

Geonhwa Kim,Jaeyeon Park,Jaehun Park,Bongjin Simon Mun,Ki-jeong Kim 한국진공학회 2017 한국진공학회 학술발표회초록집 Vol.2017 No.2