백령도 및 서울 대기오염집중측정소 에어로졸 질량 분석기 자료를 이용한 대기 중 에어로졸 화학적 특성 연구

박태현(Taehyun Park),반지희(Jihee Ban),강석원(Seokwon Kang),김영성(Young Sung Ghim),신혜정(Hye-Jung Shin),박종성(Jong Sung Park),박승명(Seung Myung Park),문광주(Kwang Joo Moon),임용재(Yong-Jae Lim),이민도(Min-Do Lee),이상보(Sang-Bo L 한국대기환경학회 2018 한국대기환경학회지 Vol.34 No.3

Electrically Tunable Solid-state Structural Color Based on Self-assembled Block Copolymer

TaeHyun PARK,HanSol KANG,CheolMin PARK 한국고분자학회 2016 한국고분자학회 학술대회 연구논문 초록집 Vol.41 No.2

Fabrication and Application of Micro Polymer Chip Platform for Rare Cell Sample Preparation

Taehyun Park 한국융합학회 2018 한국융합학회논문지 Vol.9 No.3

본 논문에서는 정확한 수의 희귀 세포 포집 및 이송을 위한 마이크로 폴리머 칩 플랫폼의 디자인과 제작, 그리고 프로토콜을 소개하고 있다. 본 플랫폼과 프로토콜은 기존의 통계학적인 샘플 준비 방법인 희석(Dilution)의 한계와 고가이며 형광염색이 요구되는 유세포분석기(Fluorescence activated cell sorter)의 단점을 극복하였다. 타켓 세포를 선택적으로 쉽고 간단하게 채집할 수 있으며 채집되는 세포의 수는 시각적으로 검증되므로 매우 정확한 방법이다. 또한, 채집된 세포들은 마이크로 챔버 등의 원하는 곳으로 세포의 손실 없이 이송 또는 주입 시킬 수 있다. 본 연구는 암진단 등을 목적으로 하는 칩 속의 실험실(Lab on a chip) 등에 필요한 희귀 세포 샘플 준비를 위해 활용 될 수 있을 뿐만 아니라 세포분석을 위한 싱글/더블/다수 세포 샘플의 준비에도 활용 가능하다. 본 논문에서 제시하는 세포 채집 플랫폼과 프로토콜을 검증하기 위해 5개의 인간 암세포(MCF-7)를 채집한 뒤 세포계수기(Hemocytometer) 안으로 주입시켜 세포의 수를 확인하였다. In this paper, a new micro polymer chip platform and protocol were developed for rare cell sample preparation. The proposed platform and protocol overcome the current limitation of the dilution method which is based on statistics and the FACS method which expensive and requires fluorescence staining. It allows collecting exact number of target cells simply and selectively because the cells are visually confirmed during the collecting process. The collected cells can be transported or spiked into a desired locations, such as a microchamber, without cell loss. This research may applicable not only to a rare cell sample preparation for Lab on a Chip cancer diagnosis, but also to a single/double/multiple cell sample preparation for a cell analysis field. To verify this platform and protocol, five human breast cancer cells (MCF-7) were collected and transported into a hemocytometer chamber.

The humidifier disinfectant case and the legislative challenges of the 20th Congress

Park, Taehyun The Korean Society of Environmental Toxicology 2016 환경독성보건학회지 Vol.31 No.-

A number of absurdities surrounding the humidifier disinfectant (HD) incident may have occurred because 1) a judicial system operates on the underlying false assumption that the involved parties are equals in knowledge, information and resource mobilization capabilities, regardless of respective real status as company or individual; 2) there is a lack of a system that mandates a company to prevent and actively manage possible catastrophes; 3) the regulatory scheme makes companies believe that as long as they are complying with the existing regulations, they have satisfied all of their responsibilities. I believe that this issue is an opportunity to bring about changes in the judicial redress system, the system of internal management of manufacturers, and the regulatory system of the government. The following regulation amendments are needed to move towards the changes stated above. First, legislation relating to victim relief that is applicable to the HD incident must be established. Second, a risk management system must be formed within the manufacturing company and to this end an institutional environment for the system must be established within regulatory framework. Furthermore, legislation must be passed that could punish companies themselves that have caused severe damage to individuals because they had failed to take necessary actions to avoid foreseeable harm. Finally, the framework of regulation must be changed so that the company, who has the necessary information regarding the product and the component chemicals used in the product, must self-directed experiment and assessment of the safety of their own products.

SEALING OF POLYMER MICRO DEVICES USING A BOILING POINT CONTROL SYSTEM

Taehyun Park(박태현),In-Hyouk Song(송인혁),Michael C. Murphy 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11

A new advanced technique for thermoplastic fusion bonding (TPB) using a Pressure-Assisted Boiling Point (PABP) control system was developed. The proposed PABP system enables precise control of both the temperature and pressure in the fusion layer. The temperature variation was ~ 0.1℃ at the target temperature and a uniform pressure distribution was accomplished. Very low aspect ratio channels (AR=1/100, 10 ㎛ in depth and 1000 ㎛ in width) were successfully sealed without deformation or collapse. Bond strengths were greater than 496 ㎪. In addition, a microfluidic system on a non-flat surface was sealed, enabling Lab-on-a-Foil technology. The PABP system can be easily built using inexpensive components and simply operated. Moreover the PABP system should be scalable for mass production and large area devices.

Optimum Morphology of Mixed-Olivine Mesocrystals for a Li-Ion Battery

Park, Kimin,Kim, Jaewon,Wi, Sungun,Lee, Sangheon,Hwang, Taehyun,Kim, Jaewook,Kang, Joonhyeon,Choi, Joon-Phil,Nam, Seunghoon,Park, Byungwoo American Chemical Society 2018 Inorganic Chemistry Vol.57 No.10

<P>In this present work, we report on the synthesis of micron-sized LiMn<SUB>0.8</SUB>Fe<SUB>0.2</SUB>PO<SUB>4</SUB> (LMFP) mesocrystals via a solvothermal method with varying pH and precursor ratios. The morphologies of resultant LMFP secondary particles are classified into two major classes, flakes and ellipsoids, both of which are featured by the mesocrystalline aggregates where the primary particles constituting LMFP secondary particles are crystallographically aligned. Assessment of the battery performance reveals that the flake-shaped LMFP mesocrystals exhibit a specific capacity and rate capability superior to those of other mesocrystals. The origin of the enhanced electrochemical performance is investigated in terms of primary particle size, pore structure, antisite-defect concentration, and secondary particle shape. It is shown that the shape of the secondary particle has just as much of a significant effect on the battery performance as the crystallite size and antisite defects do. We believe that this work provides a rule of design for electrochemically favorable meso/nanostructures, which is of great potential for improving battery performance by tuning the morphology of particles on multilength scales.</P><P>Micron-sized LiMn<SUB>0.8</SUB>Fe<SUB>0.2</SUB>PO<SUB>4</SUB> mesocrystals having various morphologies were facilely synthesized via a solvothermal method. The origin of the different electrochemical performances of the mesocrystals was investigated in terms of primary particle size, pore structure, antisite-defect concentration, and secondary particle shape. We believe that this work can provide a rule of design for the electrochemically favorable meso/nanostructures, which is of great potential for improving battery performance.</P> [FIG OMISSION]</BR>

Prevalence and Risk Factors of Abusive Behaviors in the Caregivers of People with Dementia in Korea

Taehyun Kim,Hyeon Jeong,Ji Won Han,Kyung Phil Kwak,Bong-Jo Kim,Shin-Kyeom Kim,Jeong Lan Kim,Tae Hui Kim,Seung-Ho Ryu,Seok Woo Moon,Jae Young Park,Joon Hyuk Park,Jae Nam Bae,Jong Chul Youn,Dong Young L 대한신경정신의학회 2018 PSYCHIATRY INVESTIGATION Vol.15 No.7

Objective We investigated the prevalence and risk factors of physically abusive behaviors (PhAB) and psychologically abusive behaviors (PsAB) towards people with dementia (PWD) in family caregivers, and compared their prevalences between East Asian and Western countries. Methods We estimated the prevalence and risk factors of PhAB and PsAB in 467 Korean pairs of community-dwelling PWD and their primary family caregivers. We evaluated abusive behaviors using the Modified Conflict Tactics Scale. In addition, we compared the prevalence of abusive behaviors between Asian and Western countries through a meta-analysis on 12 studies including the current one. Results More than a half of the caregivers reported PsAB and about one out of seven caregivers admitted PhAB within past three months. PsAB and PhAB were slightly more prevalent in East Asian countries than in Western countries. Non-Alzheimer type and moderate to severe behavioral and psychological symptoms of dementia were associated with the risk of PhAB but not with the risk of PsAB. Severe care burden and low income were associated with the risk of PhAB and PsAB. Conclusion PhAB and PsAB were as prevalent in the family caregivers of PWD in Asian countries including Korea as in Western countries. Prevention strategies should be implemented according to the type of abusive behaviors.

A rollable ultra-light polymer electrolyte membrane fuel cell

Park, Taehyun,Kang, Yun Sik,Jang, Segeun,Cha, Suk Won,Choi, Mansoo,Yoo, Sung Jong Nature Publishing Group 2017 NPG Asia Materials Vol.9 No.-

<P>We have developed a highly flexible, ultra-light and thin polymer electrolyte membrane fuel cell that can be used as a portable power source for flexible electronics. To achieve such flexibility and ultra-lightness, we fabricated a thin flow-field plate using a thermal imprinting process and combined it with a laser-machined metal current collector. The air-breathing fuel cell, with a thickness of 0.992 mm and a weight of 2.23 g, demonstrated a total power of 508 mW and a performance degradation of <10% after severe bending fatigue (200 repeated bends). This high power per weight (0.228 W g(-1)) and robust bending durability have never been observed before. The highly flexible architecture enabled the operation of the fuel cell in an S-shape or even in a rolled-up state without any significant performance loss. We have fabricated a cylindrical planar stack of 10 fuel cells and successfully carried out its outdoor operation to demonstrate its practical applications in various fields.</P>

Multi-block FEC for reprogramming wireless sensor networks

Park, Taehyun,Kim, Seung, Young,Kwon, Gu-In IET 2013 Electronics letters Vol.49 No.14

<P>Reprogramming a wireless sensor network requires accurate broadcast of the code to its all nodes. A multi-block forward error correction technique was used, in which blocks were encoded using a rateless code, such as a Luby transform (LT) code. When relaying data, a node salvages any error-free blocks from a corrupted frame and uses them in constructing a new frame. This creates diversity in the data relayed by the nodes, giving downstream nodes an improved chance of obtainining a subset version of any block. Experiments show that this approach achieves significant reduction in network traffic.</P>

Augmentation method of triple phase boundary in thin film solid oxide fuel cell via physical vapor deposition.

Park, Taehyun,Chang, Ikwhang,Cha, Suk Won American Scientific Publishers 2013 Journal of Nanoscience and Nanotechnology Vol.13 No.12

<P>Triple phase boundaries (TPBs) where electrode, electrolyte, and reactant meet altogether were augmented in thin film solid oxide fuel cell when Pt cathode was deposited on yttrium-doped barium zirconate electrolyte (BZY) via sputter. The augmented TPBs were observed to exist as three-dimensional structures, which is different from what are known to exist as two-dimensional planes or interfaces, by using energy dispersive spectroscopy (EDS). The permeating phenomenon of sputtered Pt into BZY was found to depend on dc sputtering power. Polarization curves showed increasing tendency of maximum powers in accordance with increasing thickness of Pt cathode and spectra of ac impedances showed decreasing tendency of faradaic resistances. If TPBs were located as an interfacial structure between electrode and electrolyte, oxygen could not diffuse well into TPBs, causing radius of semicircle in impedance spectra to decrease. The results are violating this expectation. As a result, as long as charge transfer resistance is a function of temperature, reactant concentration, activation barrier and TPB length, TPB must be only a factor to affect the results in this experiment.</P>