Modification of Nafionr Using 3-mercaptopropyl Trimethoxysilane

박용일,이혜정,박성범,오명훈,조경식,Satoshi Suzuki,Masayuki Nagai,Fritz B. Prinz 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.56 No.4

The modification of a Nafionr membrane by incorporation of 3-mercaptopropyltrimethoxysilane (MPTS) is investigated through a simple sol-gel process to reduce the methanol crossover without sacrificing the proton conductivity. The MPTS monomers incorporated in the Nafionr matrix are hydrolyzed, forming a silicate phase by polymerization. The thiols of MPTS are finally oxidized into a sulfonic acid form. Compared to Nafionr, the obtained modified membranes show significantly reduced solvent uptake with an accompanying low volume expansion ratio. A maximum 42% methanol crossover reduction is observed with improved proton conductivity. The proton conductivities of the obtained membranes increase from 8.0 × 10−3 Scm−1 to 1.9 × 10−2 Scm−1 at 70 ℃ with increasing MPTS amount from 0 to 1.96 wt%. The low methanol crossover and the high proton conductivity of the modified membranes are attributable to the MPTS-derived silicate phase blocking the ionic cluster pathway and to the simultaneous supply of a high sulfonic acid concentration to the Nafionr matrix.

Preparation of Medium-Molecular Weight Chitosan and Its Antimicrobial Activity on Methicillin-Resistant Staphylococcus aureus

박용일,문혜란,김성욱,박제권 한국키틴키토산학회 2010 한국키틴키토산학회지 Vol.15 No.1

Medium-molecular weight chitosans (MMCs), ranging from 60 to 800 kDa, was prepared by enzymatic digestion of high molecular weight of native chitosan using crude enzyme solution containing chitosanolytic activity obtained from germinated barley. MMCs were compared with chitosans of different molecular weight, water-soluble glycol chitosan, and intact fucoidan known as sulfated polysaccharide and its oligosaccharides for their antimicrobial activities against the Gram-positive methicillinresistant Staphylococcus aureus (MRSA), and two Gram-negative bacteria Psedomonas auruginosa and Salmonellar spp (CCARM 8009). One of MMCs, named as MMC-P1 (63.8 kDa ), at 50 μg/ml of minimum inhibitory concentration (MIC)showed the most significant antimicrobial activities in a dose-dependent manner against MRSA, but negligible against P. aeruginosa and Salmonellar spp (CCARM 8009). Although native chitosan with positively charged NH3+groups in diluted acidic solution showed considerable antimicrobial activities when these bacteria were treated at high concentration of chitosan (1mg/ml), no significant inhibitory effect of native chitosan, glycol chitosan, intact fucoidan or its oligosaccharides was observed at the minimum inhibitory concentration (MIC) of MMC-P1. These results suggest that specific molecular weight of chitosan may be dominant factor directly affecting on antimicrobial activity especially against MRSA.

Filter-free luminescence diagnostics using upconverting nanoparticles

박용일 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.0

We report a new detection method that obviates the need for filters and is much more sensitive since the target signal can be integrated. This approach exploits the unique optical properties of upconverting nanoparticles (UCNP). Optically excited UCNP emits long lifetime (several milliseconds) luminescent light even when the exciting light is turned off. This feature enables filter-free imaging of the particles by time-gated fluorescence imaging. Importantly, the method eliminates the interference from excitation light and short-lived background autofluorescence, which significantly improves the signal-to-noise ratio. We expect this portable and sensitive time-gated imaging system is applicable for detecting disease markers.

Acute Idiopathic Hemorrhagic Pericarditis with Cardiac Tamponade as the Initial Presentation of Acquired Immune Deficiency Syndrome

박용일,박성원,김현태,이보라,곽예경,조욱현,최석구,서정주 연세대학교의과대학 2010 Yonsei medical journal Vol.51 No.2

This paper presents a case of cardiac tamponade with idiopathic hemorrhagic pericarditis as the initial symptom of human immunodeficiency virus (HIV) infection. A 29-year-old male came to the emergency room with a sudden onset of dizziness. Upon arrival, he was hypotensive although not tachycardic, and his jugular venous pressure was not elevated. His chest X-rays revealed a mild cardiomegaly. Transthoracic echocardiography revealed a large amount of pericardial effusion with a diastolic collapse of the right ventricle, a dilated inferior vena cava with little change in respiration, and exaggerated respiratory variation of mitral inflow velocities, representing echocardiographic evidence of cardiac tamponade. After pericardiocentesis, his blood pressure improved to 110/70 mmHg without inotropics support. Serial 12-lead electrocardiograms during hospitalization revealed upwardly concave diffuse ST-segment elevation followed by a T-wave inversion suggestive of acute pericarditis. Pericardial fluid cytology and cultures for bacteria, mycobacteria, adenovirus, and fungus were all negative. HIV enzyme-linked immunosorbent assay (ELISA) was positive and confirmed by Western blot. The CD4 cell count was 168/mm3. Finally, the diagnosis of cardiac tamponade due to HIV-associated hemorrhagic pericarditis was made. It was concluded that HIV infection should be considered in the diagnosis of unexplained pericardial effusion or cardiac tamponade in Korea.

충수 절제술후 합병된 기계적 장폐색에 대한 치료 경험

박용일,유창헌,김상효 대한외과학회 1991 대한외과학회 학술대회 초록집 Vol.1991 No.11

일본어 교육을 위한 [-続ける]문의 구조와 의미 고찰

박용일 한국외국어대학교 일본연구소 2011 日本硏究 Vol.48 No.-

本稿では継続を表す日本語の[-続ける]文において[事件の反復]と[行為の反復]という二通りの意味が現れるという事実を示すと共に、このように現れる二通りの意味が[-続ける]文の構造とどのように係わっているのかを示した。このような結果を通してⅠ章で提起した(2a)のような[-続ける]文に対応する韓国語がなぜ(2b)と(2c)のような二通りの表現で現れるのかその理由を提示した。 (2) a. みんなが地下水を買い続けた。 b. 모두가 지하수를 계속 샀다. c. 모두가 지하수를 사기를 계속했다. 本稿の手順を具体的にまとめると、[-続ける]文に二つの意味が現れ得るという可能性を[-続ける]文と対応する韓国語の表現を通して確認し、実際[-続ける]文において[事件の反復]と[行為の反復]の意味が現れるという事実を観察した。また、[-続ける]文に現れるこのような二通りの意味が[-続ける]文の構造と係わっていることを示すために、受動文現象、[何も]と否定語現象、[おVになる]と主語現象を通して[-続ける]文が単文構造を持っているということを示すと同時に、受動文現象、[おVになる]と主語現象を通して[-続ける]文が複文構造を持っているということを示した。このような結果をもって[-続ける]文の二通りの構造と二通りの意味が相互どのような関係を持っているのかを日本語母語話者の手助けを借り、[-続ける]文が複文構造の場合は[事件の反復]と[行為の反復]の意味が両方現れるが、[-続ける]文が単文構造の場合は[行為の反復]の意味だけが現れるという事実を示した。 このような結果は、[-続ける]文(2a)に対応する韓国語がなぜ(2b)と(2c)の二通りに現れるのかという理由について、(2b)は[行為の反復]の意味を持っている単文構造であり、(2c)は[事件の反復]の意味を持っている複文構造であるため、(2a)が[行為の反復]の意味を持つ単文構造の場合は(2b)と対応しており、(2a)が[行為の反復]や[事件の反復]の意味を持っている複文構造の場合は(2c)と対応していると説明することができる。

한일 모국어 화자가 갖는 [먹다]와 [食べる]의 인지적 동이성

박용일 한국일본학회 2021 한국일본학회 학술대회 Vol.2021 No.08

일본어 교육을 위한 일본어 복합동사와 이에 대응하는 한국어 패턴의 고찰

박용일 한국외국어대학교 일본연구소 2010 日本硏究 Vol.46 No.-

本稿では日本語の複合動詞が韓国語で表される場合、どのような対応パターンで現れるのかるを考察した。本稿の考察結果は次のようにまとめられる。Ⅰ. パターンA(前項=後項)· A-1: 前項動詞と後項動詞にそのまま対応して韓国語に現れる。 · A-2: 前項動詞に対応して韓国語に現れる。· A-3: 前項動詞と対応して韓国語に現れ、後項動詞に対応する韓国語は前項動詞の後ろで前項動詞に意味を添加する。· A-4: 前項動詞、後項動詞に対応する韓国語は日本語の場合と反対に現れる。 Ⅱ. パターンB(前項<後項)· B-1: 前項動詞に対応する韓国語は後項動詞の前で後項動詞に付加的な説明を添加する。 · B-2: 前項動詞に対応する韓国語は現れない。Ⅲ. パターンC(前項>後項)· C-1: 前項動詞に対応する韓国語で現れる。 · C-2: 前項動詞に対応する韓国語で現れるか、ここに付加的な意味を添加して現れる。Ⅳ. パターンD(前項 ? 後項) · 一つの慣用的な単語もしくは慣用語で現れるか、前項動詞や後項動詞の意味とは関係のない韓国語で現れる。

나노기공성 기판을 사용한 산화물박막의 제조

박용일,Park, Yong-Il,Prinz, Fritz B. 한국세라믹학회 2004 한국세라믹학회지 Vol.41 No.12

현재까지 개발되어 온 고체산화물 연료전지는 전해질로 사용되는 산소이온전도성 산화물의 저온에서의 낮은 전도도로 인해 그 사용영역이 제한되어 왔으며, 기판재료가 연료가스 확산층으로 사용되어야 한다는 점 때문에 저온작동을 위한 박막화 역시 명확한 한계를 가지고 있다. 이러한 문제점은 고도의 평활도를 갖는 균일한 나노기공성 기판재를 도입함으로써 해결될 수 있으며, 본 연구에서는 나노기공성 기판에 비정질 금속박막을 증착/산화하는 방안을 제시한다. 초박막형 성공정으로서, 산화 후 산소이온전도성 산화물을 구성하는 합금 타겟을 장착한 DC-magnetron sputter를 사용하여 $20{\sim}200nm$의 기공크기를 갖는 나노기공성 양극산화 알루미나 기판에 비정질 금속합금막을 형성하여 산화/열처리 과정을 거쳐 초박막 산화물 전해질의 제조공정을 실현하였다. 얻어진 박막의 가스투과특성, 입자/입계의 관찰, 상전이에 따른 결정구조/미세구조변화를 관찰하여 초박막 증착 및 전해질의 나노구조제어에 필요한 제반 기본물성데이터를 확보하였다. Solid oxide fuel cells have a limitation in their low-temperature application due to the low ionic conductivity of electrolyte materials and difficulties in thin film formation on porous gas diffusion layer. These problems can be solved by improvement of ionic conductivity through controlled nanostructure of electrolyte and adopting nanoporous electrodes as substrates which have homogeneous submicron pore size and highly flattened surface. In this study, ultra-thin oxide films having submicron thickness without gas leakage are deposited on nanoporous substrates. By oxidation of metal thin films deposited onto nanoporous anodic alumina substrates with pore size of $20nm{\sim}200nm$ using dc-magnetron sputtering at room temperature, ultra-thin and dense ionic conducting oxide films with submicron thickness are realized. The specific material properties of the thin films including gas permeation, grain/gran boundaries formation, change of crystalline structure/microstructure by phase transition are investigated for optimization of ultra thin film deposition process.

고효율 소형 연료전지의 개발 : I.유기-무기 나노복합 전해질막의 합성

박용일,문주호,김혜경,김석환,Park, Yong-Il,Moon, Joo-Ho,Kim, Hye-Kyung,Kim, Suk-Hwam 한국세라믹학회 2005 한국세라믹학회지 Vol.42 No.1

New fast proton-conducting organic-inorganic nanocomposite membranes were successfully fabricated using polymer matrix obtained through proper oxidation of thiol ligands in (3-Mercaptopropyl) trimethoxysilane (MPTS) and hydrolysis/condensation reaction of (3-glycidoxypropyl) trimethoxysilane (GPTS). The obtained nanocomposite membranes showed relatively hirh proton-conductivity over $10^{-2}S/cm$ at $ 25^{circ}C$. The proton conductivities of the fabricated composite membranes increased up to $3.6{\times}10^{-1}$ S/cm cm by increasing temperature and relative humidity to $70^{circ}C$ and 100 $100RH\%$. The high proton conductivity of the composites Is due to the proton conducting path through the GPTS-derived 'pseudo-polyethylene oxide 'network in which sulfonic acid ligands work as a proton donor. (3-Mercaptopropyl) trimethoxysilane(MPTS)의 thoil기(-SH)의 적절한 산화 및 (3-glycidoxypropyl) trimethooxysilane(GHS)와의 수화/중축합 반응을 통하여 얻어진 고분자 기질을 사용하여 새로운 고 프로톤 전도성 유기-무기 나노복합막을 성공적으로 합성하였다. 합성된 나노복합막으로부터 얻어진 프로톤 전도도는 $25^{circ}C$에서 $10^{-2} S/cm$ 이상의 높은 값을 나타내었으며, 온도와 상대습도를 $70^{circ}C$와 $100RH\%$로 증가시킴에 따라 전도도는 $3.6{\times}10^{-1}$ S/cm까지 증가하였다. 복합체의 높은 프로톤 전도도는 MPTS 말단의 thiol의 산화에 의해 얻어지는 아황산기$(-SO_{3}^{-})$가 프로톤 donor로서 작용하고, GHS로부터 유도된 'pseudo polyethylene oxide' 네트워크가 프로톤의 전도 path로 작용하고 있음을 나타낸다.