무등산국립공원의 부착규조류 분포와 생물학적 수질평가

박정원(JungWon Park) 국립공원연구원 2023 국립공원연구지 Vol.14 No.1

본 조사는 무등산국립공원의 부착규조류 분포와 생물학적 수질평가를 위해 모두 17개의 정점을 선정하여 2022년 4월부터 9월까지 실시하였다. 환경요인은 수온, pH, 전기전도도, BOD, TN 그리고 TP 등을 분석하였다. 출현한 부착규조류는 모두 111종류였고, 우점종은 Achnanthes convergens, Cocconeis placentula var. lineata, Gomphonema clevei 등을 포함하여 모두 13종류였다. 이들 중 Cocconeis placentula var. lineata는 모두 11회 우점종으로 출현하여 가장 많은 출현횟수를 보였다. 생태 분류군중 청수성 분류군의 상대빈도는 20.63 ~ 99.57%, 오탁성 분류군은 0 ~ 50.08%였다. 생물학적 수질평가에서 TDI는 12.5 ~ 99.7이었고, 수질등급은 E ~ A등급이었으며, DAIpo는 38.22 ~ 99.79였으며 수질등급은 D ~ A등급이었다. 결론적으로 무등산국립공원의 가장 대표적인 부착규조는 출현횟수, 우점빈도 등에서 Cocconeis placentula var. lineata가 가장 대표적인 종으로 나타났다. 생물학적 수질평가는 대부분의 양호한 상태이나 일부 지점은 수환경에 대해 지속적인 모니터링이 필요한 것으로 보인다. This survey was conducted to evaluate the distribution and biological water quality of epilithic diatoms from April to September 2022 by selecting a total of 17sites in Mudeungsan National Park, Korea. Environmental factors were analyzed such as water temperature, pH, electrical conductivity, BOD, TN and TP. A total of 111 species of epilithic diatoms appeared, and the dominant species were 13 species including Achnanthes convergens, Cocconeis placentula var. lineata, and Gomphonema clevei. Among dominant species, C. placentula var. lineata appeared as the dominant species 13times, showing the highest number of appearances. Among the ecological taxa, the relative frequencies of saproxenous group ranged from 20.63 to 99.57%, saprophilous group ranged from 0 to 50.08%. In evaluation of biological water quality, TDI was 12.5 ~ 99.7, water quality grade was E ~ A, DAIpo was 38.22 ~ 99.79, and water quality was D ~ A grade. In conclusion, the most representative epilithic diatom of Mudeungsan National Park was C. placentula var. lineata in terms of appearance number and dominance frequency. Biological water quality assessments are mostly in good condition, but some points appear to require continuous monitoring of the aquatic environment.

태안해안국립공원 바람아래 특별보호구역의 지형 및 염생식물 분포특성 연구

박정원(Jeongwon Park),서종철(Jongchul Seo),김진석(Jinseok Kim),오선관(Sunkwan Oh),박정원(Jungwon Park) 국립공원연구원 2013 국립공원연구지 Vol.4 No.1

본 연구는 바람아래 할미섬 특별보호구역의 자연해안 복원 연구를 위하여 현재의 해빈의 높이, 면적, 해안의 길이, 사구정상의 높이 등 정확한 지형의 현황을 분석하고 지형특성에 따른 사구·염생식물 분포를 분석하고자 하였다. 할미섬 지형의 최고높이는 17m이며 제일 낮은 높이는 평균 3m에서 5m로 섬 남단 만입에서 남동쪽 니질조간대 지역이다. 연구지역내 총 소산식물은 17목 23과 40속 49종 3변종 8외래종이 생육하고 있으며 곰솔군락, 갈참나무군락, 보리장나무군락, 아까시나무군락, 순비기나무군락 등 5개 목본군락과 띠군락, 갯그령군락, 갯잔디군락, 나문재군락, 왕잔디군락, 갯메꽃군락, 해홍나물군락, 천일사초군락, 갯쇠보리군락, 통보리사초군락 등 10개 염생·사구식물군락이 분포하고 있으며 갯그령-띠군락, 띠-갯메꽃군락, 띠-갯그령군락, 띠-은백양나무군락 등 4개의 혼합군락이 분포하고 있다. 식물의 공간적 분포 특성은 곰솔(Pt1), 갯그령(Em2,3,4), 갯잔디(Zs5)를 제외한 식생군락의 대부분이 10m2에서 500m2의 작은 패치형태를 띄고 있으며 높이는 평균 4m에서 6m 사이, 해안선으로부터 거리는 100m에서 150m 사이에 분포하고 잇는 것으로 분석되었다. This study was carried out to investigate the exact current status of the topography such as the present beach elevation and area, coastline and the height of the dune crest, with the analysis of the distribution of the sand dune·halophytes on geomorphic characteristics for the restoration of natural coast in the protection zone of Baramarye Halmi-island. Halmi-island has the maximum height of 17m and the lowest height of average 3m to 5m, which is the muddy tidal flat area located southeast of the embayment on the southern tip of the island. The total distribution of plants in the research sites are 17 orders, 23 families, 40 genus, 49 species and 8 exotic species: 5 arbors communities including Pinus thunbergii, Quercus aliena, Elaeagnus glabra, Robinia pseudo-acacia, Vitex rotundifolia etc., 10 halophytes and sand dune plants communities including Calystegia soldanella, Suaeda maritima, Carex scabrifolia, Ischaemum anthephoroides, Carex kobomugi etc and 4 mixed communities including Elymus mollis-Imperata cylindrica var. koenigii, Imperata cylindrica var. koenigii-Calystegia soldanella, Imperata cylindrica var. koenigii-Elymus mollis, Imperata cylindrica var. koenigii-Populus alba etc. The spatial distribution characteristics of plants are identified that the most plant community are distributed in the distance of between 100m to 150m from the coastline, with the small-scale patch structure of 10m2 to 500m2 and the height of average 4cm to 6cm except Pinus thunbergii (Pt1), Elymus mollis (Em2,3,4) and Zoysia sinica (Zs5).

Imaging Biological Systems by Cryo- and Liquid-Electron Microscopy

Jungwon Park(박정원) 한국고분자학회 2022 한국고분자학회 학술대회 연구논문 초록집 Vol.47 No.2

Role of phosphate in ruthenium-complex-sensitized TiO₂ system for hydrogen production: Mechanism and kinetics

Park, Cheolwoo,Park, Jeesu,Park, Jaehoon,Heo, Iljeong,Kim, Wooyul,Kim, Jungwon Elsevier 2019 CATALYSIS TODAY - Vol.335 No.-

<P><B>Abstract</B></P> <P>Most Ru(II) complex-sensitized TiO<SUB>2</SUB> systems for hydrogen (H<SUB>2</SUB>) production suffer from instability of the photosensitized system because the anchoring groups of Ru(II) dyes, which are required for their adsorption on TiO<SUB>2</SUB>, are intrinsically vulnerable to chemical and photochemical cleavage. In this study, a new method that enables the use of a Ru(II) dye without any anchoring groups (Ru(bpy)<SUB>3</SUB> <SUP>2+</SUP>) was developed and investigated. The stable photocatalytic efficiency in repeated H<SUB>2</SUB> production cycles under visible-light irradiation indicates that the Ru(II) dye without anchoring groups is highly stable during dye-sensitized H<SUB>2</SUB> production. The dye-sensitized H<SUB>2</SUB> production in the Ru(bpy)<SUB>3</SUB> <SUP>2+</SUP>-sensitized TiO<SUB>2</SUB> system comprising Ru(bpy)<SUB>3</SUB> <SUP>2+</SUP> as a photosensitizer, platinized TiO<SUB>2</SUB> (Pt-TiO<SUB>2</SUB>) as a cocatalyst-electron mediator, and ethylenediaminetetraacetic acid as an electron donor was negligible. However, the addition of phosphate (PO<SUB>4</SUB> <SUP>3–</SUP>) to the Ru(bpy)<SUB>3</SUB> <SUP>2+</SUP>-sensitized TiO<SUB>2</SUB> system enabled the production of H<SUB>2</SUB> via dye sensitization in the absence of any anchoring groups on the dye. The adsorption of PO<SUB>4</SUB> <SUP>3–</SUP> changed the surface charge of Pt-TiO<SUB>2</SUB> from positive to negative under acidic conditions, thereby inducing adsorption of cationic Ru(bpy)<SUB>3</SUB> <SUP>2+</SUP> on the surface of Pt-TiO<SUB>2</SUB> and facilitating electron transfer from excited Ru(bpy)<SUB>3</SUB> <SUP>2+</SUP> to the conduction band of TiO<SUB>2</SUB>. The PO<SUB>4</SUB> <SUP>3–</SUP> adsorption-induced change in the surface charge and the subsequent adsorption of Ru(bpy)<SUB>3</SUB> <SUP>2+</SUP> on the surface of PO<SUB>4</SUB> <SUP>3–</SUP>-adsorbed Pt-TiO<SUB>2</SUB> were confirmed by zeta potential measurements and Fourier transform infrared spectroscopy, respectively. In contrast with H<SUB>2</SUB> production, the presence of PO<SUB>4</SUB> <SUP>3–</SUP> had little effect on the kinetics of anionic chromate (CrO<SUB>4</SUB> <SUP>2–</SUP>) reduction in the Ru(bpy)<SUB>3</SUB> <SUP>2+</SUP>-sensitized TiO<SUB>2</SUB> system. This result indicates that electron transfer from Pt to the electron acceptor on PO<SUB>4</SUB> <SUP>3–</SUP>-adsorbed Pt-TiO<SUB>2</SUB> is highly dependent on the charge character of the electron acceptor (i.e., electron transfer to the cationic electron acceptor is more favored). The negative charge on the surface of Pt-TiO<SUB>2</SUB> induced by the adsorption of PO<SUB>4</SUB> <SUP>3–</SUP> attracts the positively charged protons to the surface, which kinetically enhanced electron transfer from Pt to the protons. The (photo)electrochemical data demonstrate that PO<SUB>4</SUB> <SUP>3–</SUP> adsorbed on Pt-TiO<SUB>2</SUB> facilitates the interfacial electron transfer processes by enhancing the adsorption of Ru(bpy)<SUB>3</SUB> <SUP>2+</SUP> and attracting protons to the surface. The positive effect of PO<SUB>4</SUB> <SUP>3–</SUP> on H<SUB>2</SUB> production increased with increasing PO<SUB>4</SUB> <SUP>3–</SUP> concentration and decreasing pH, where the conditions are more favorable for PO<SUB>4</SUB> <SUP>3–</SUP> and proton adsorption on the surface of Pt-TiO<SUB>2</SUB>. Among the five anions evaluated in this study (PO<SUB>4</SUB> <SUP>3–</SUP>, AsO<SUB>4</SUB> <SUP>3–</SUP>, F<SUP>–</SUP>, NO<SUB>3</SUB> <SUP>–</SUP>, and SO<SUB>4</SUB> <SUP>2–</SUP>), PO<SUB>4</SUB> <SUP>3–</SUP> was most efficient and facilitated stable H<SUB>2</SUB> production.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Adsorption of PO<SUB>4</SUB> <SUP>3–</SUP> changes the surface charge of TiO<SUB>2</SUB> from positive to negative. </LI> <LI> PO<SUB>4</SUB> <SUP>3

Liquid Phase TEM Observation for Conformational Dynamics of Single Polymer Chains

Jungwon Park(박정원) 한국고분자학회 2021 한국고분자학회 학술대회 연구논문 초록집 Vol.46 No.2

Macromolecules have a chain structure made up of repeating building blocks and they are naturally flexible in solutions. In many solution systems of biological and synthetic polymers, macromolecules exist in a range of distinct conformations and undergo dynamic transitions between them, responsible for their specific functions and physicochemical properties, and determining a pathway to construct high-level structures. For example, intrinsically disordered proteins, which account for one-third of the proteins in the human proteome, do not adopt a standardized three-dimensional structure and their spontaneous interconversion between unfolded states are crucial in dynamic biological processes. In addition, highly regulated by complex molecular interactions and resulting conformational changes, various synthetic polymers form a wide range of high-order structures by self-structuring of individual molecules. Thus, it is important to understand the intrinsic structural diversity and dynamic behaviors of individual macromolecules at the single-chain level. Liquid-phase transmission electron microscopy (LPTEM) has recently enabled in situ observations of polymers, such as polystyrene sulfonate and poly(ethylene oxide) in aqueous solutions. It provides nanometer resolution in tracking individual molecules in solutions. Advancing LPTEM, here we achieve high-resolution tracking of dendronized polymer chains in graphene liquid cell TEM and elucidate a distinct individual chain architecture and conformational fluctuations of a single linear semi-flexible polymer in a theta solvent. Investigation of the single-chain dynamics combined with molecular dynamic (MD) simulations directly reveals that the degree of intra-chain interactions induces dynamic structural fluctuations between the coiled and elongated conformations of semi-flexible polymers. Additionally, we observe non-equilibrium single chain motions, showing that single-chain trajectories can be highly affected by the locally heterogeneous environment.

Policy Consultation on Strengthening the Capacity of Foresight for Science, Technology, and Innovation(STI) Strategic Planning in Vietnam 2019-2020

Jungwon Lee,Byeongwon Park,Yong In Choi,Young Il Park,Yoo Hyung Won,Hyun Yim,Bach Tan Sinh,Le Dinh Tien,Ta Doan Trinh 과학기술정책연구원 2019 조사연구 Vol.- No.-

A Low-Power Gigabit CMOS Limiting Amplifier Using Negative Impedance Compensation and Its Application

Jungwon Han,Kwisung Yoo,Dongmyung Lee,Kangyeop Park,Wonseok Oh,Sung Min Park IEEE 2012 IEEE transactions on very large scale integration Vol.20 No.3

<P>This paper presents a low-power, gigabit limiting amplifier (LA) for application to optical receivers that employ the negative impedance compensation technique not only to enhance the gain and bandwidth characteristics simultaneously, but also to allow low-voltage, low-power operations. Test chips of the LA were implemented in a standard 0.18-μ m CMOS process, demonstrating 2.5-Gb/s operation with 40-dB gain, 0.053-UI rms jitter for 2<SUP>31</SUP>-1 pseudorandom bit sequence inputs, 9.5-mV<SUB>pp</SUB> input sensitivity for 10<SUP>-12</SUP> bit error rate (BER), and 5.2-mW power dissipation from a single 1.2-V supply. The chip core occupies the area of only 0.25 × 0.1 mm<SUP>2</SUP> . The proposed LA was adopted to realize a low-power, gigabit optical receiver. Fabricated using the same 0.18-μm CMOS technology, the measured results of the optical receiver chip reveal 132.6-dB Ω transimpedance gain, 2.7-GHz bandwidth even with a large 1.5-pF input parasitic capacitance, -16-dBm optical sensitivity for 10<SUP>-12</SUP> BER, and 51-mW power dissipation from a single 1.8-V supply. The area of the whole chip is 1.75 × 0.45 mm<SUP>2</SUP>.</P>

From the Politics of Recognition to the Politics of Antagonism : The Rise of Populism and the Retreat of Democracy in Post-Communist Hungary

Jungwon Park 한국정치사회연구소 2022 한국과 국제사회 Vol.6 No.2

The purpose of this thesis is to analyze political changes in post-Communist Hungary, using the notion of the “politics of recognition and antagonism” developed, respectively, from Axel Honneth’s theory of “recognition struggle” and Carl Schmitt’s concept of “the political.” In Hungary during the system transformation period of 1990-2010, a relatively consolidated democracy was maintained and a politics of recognition was sustained. Since 2010, however, Hungary’s politics has widely been considered to have changed enormously. Hungary’s populism under Orbán has been justified as illiberal democracy. His regime has suppressed democratic and opposite forces, severely infringing on the freedom of the press and speech. The regime has also mobilized nationalistic sentiments in Hungary and has strongly shown anti-EU and anti-refugee policies. Because of Orbán’s populism, a politics of recognition has been transformed into a politics of antagonism in Hungary. When we apply Giovanni Sartori’s theory of party systems to Hungary, it seems that the country is situated on the border between a predominant party system and a hegemonic party system.

Dual-Functional Electrocatalyst Derived from Iron-Porphyrin-Encapsulated Metal–Organic Frameworks

Park, Jungwon,Lee, Hyunjoon,Bae, Young Eun,Park, Kyoung Chul,Ji, Hoon,Jeong, Nak Cheon,Lee, Min Hyung,Kwon, Oh Joong,Lee, Chang Yeon American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.34

<P>Active, stable electrocatalysts based on non-precious metals for the oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) are critical for the development of cost-effective, efficient renewable energy technologies. Here, Fe/Fe3C-embedded nitrogen-doped carbon was fabricated via pyrolysis of iron-porphyrin-encapsulated mesoporous metal organic frameworks [PCN-333 (Fe), where 'PCN' stands for 'porous coordination network'] at 700 degrees C. The various characterization techniques confirmed that Fe- and Fe3C-containing Fe-N-C material (FeP-P333-700) was successfully prepared by pyrolysis of porphyrin-encapsulated PCN-333 (Fe). FeP-P333-700 exhibited superior electrocatalytic performance for the ORR and HER owing to the synergistic effect of Fe/Fe3C and Fe-N-C active sites.</P>

3D structure of individual nanocrystals in solution by electron microscopy

Park, Jungwon,Elmlund, Hans,Ercius, Peter,Yuk, Jong Min,Limmer, David T.,Chen, Qian,Kim, Kwanpyo,Han, Sang Hoon,Weitz, David A.,Zettl, A.,Alivisatos, A. Paul American Association for the Advancement of Scienc 2015 Science Vol.349 No.6245

<P><B>Looking at teeny tiny platinum particles</B></P><P>Electron microscopy is a powerful technique for taking snapshots of particles or images at near-atomic resolution. Park <I>et al.</I> studied free-floating platinum nanoparticles using electron microscopy and liquid cells (see the Perspective by Colliex). Using analytical techniques developed to study biological molecules, they reconstructed the threedimensional features of the Pt particles at near-atomic resolution. This approach has the scope to study a mixed population of particles one at a time and to study their synthesis as it occurs in solution.</P><P><I>Science</I>, this issue p. 290; see also p. 232</P><P>Knowledge about the synthesis, growth mechanisms, and physical properties of colloidal nanoparticles has been limited by technical impediments. We introduce a method for determining three-dimensional (3D) structures of individual nanoparticles in solution. We combine a graphene liquid cell, high-resolution transmission electron microscopy, a direct electron detector, and an algorithm for single-particle 3D reconstruction originally developed for analysis of biological molecules. This method yielded two 3D structures of individual platinum nanocrystals at near-atomic resolution. Because our method derives the 3D structure from images of individual nanoparticles rotating freely in solution, it enables the analysis of heterogeneous populations of potentially unordered nanoparticles that are synthesized in solution, thereby providing a means to understand the structure and stability of defects at the nanoscale.</P>