• Journal of the Korean Chemical Society
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• v.42 no.6
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• pp.657-663
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• 1998

New asymmetric dimer, 7,7'-substituted (or H)-4-oxo-2,2'- dialkyl-l,l',2,2'-dibenzothiazine-3,3'dicarboxylic acid methyl ester-1,1,1',1'-tetraoxide 3,4'-yl ethers 2a-d were synthesized through the oxidative dimerization of 7-substituted (or H)-4-hydroxy-2-alkyl-1,2-benzothiazine-3-carboxylic acid methyl ester 1,1-dioxides la-d using silver oxide($Ag_2O$). 4-Oxo-2,2'-dialkyl-1,1'2,2'-dibenzothiazine-3,3'-dicarboxylic acid methyl ester-1,1,1',l'-tetraoxide 3,4'-yl ether 2c was identified by X-ray crystal structure determination.

• KSBB Journal
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• v.11 no.4
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• pp.420-430
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• 1996

One-step immuno-chromatography assay system for heat-killed Salmonella typhimurium antigens was developed. Three major components used were a glass fiber membrane (placed at the bottom of the system) with an antibody (specific to the analyse, detection antibody)-gold conjugate deposited in a dry state on the surface, a nitrocellulose membrane (middle) with an antibody (also, specific to the analyse but recognized different epitome: capture antibody) and anti-detection antibody immobilized in spatially separated areas, and a cellulose membrane (top) as absorption pad. These membranes were partially superimposed such that a wicking of aqueous solution containing sample can continuously take place through membranes. Variables that affected the system performance were the concentration of capture antibody, the location on the membrane, inert protein used for blocking of the membrane and for carrying the sample, and the concentration of the gold conjugate. Under optimal conditions, within 15 minutes after absorption of a sample solution from the bottom of the system antigen-antibody complexes of sandwich type were formed on the membrane surface area with immobilized capture antibody and a color signal was generated in proportion to the analyse concentration. The minimum do tection limit of the analyse was $1{\times}106$ Salmonella cells/mL.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.111-111
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• 1999

반도체 소자의 고집적화 및 고속화에 따라 다층 금속배선에서의 RC 지연이 전체 지연의 주된 요소로 되고 있다. 이런 RC 진연을 줄이기 위해서 현재 다층 금속배선의 층간 절연막으로 사용하고 있는 SiO2 박막(k~3.9)을 보다 낮은 유전상수(low-k)를 가지는 물질로 대체할 것이 요구된다. 층간 절연막으로서 가져야 할 가장 중요한 것은 낮은 유전상수와 높은 열적안정성($\geq$45$0^{\circ}C$)이다. 본 연구에서는 Toluene을 precursor로 사용한 PECVD방법으로 low-k 유사중합체 유기박막을 성장시켰으며 부동한 온도에서 성장된 박막의 특성을 비교하여 증착온도가 박막의 특성에 미치는 영향에 대하여 조사하였다. 유사중합체 유기박막은 platinum(Pt)기판과 silicon 기판위에 같이 증착되었다. Precursor는 4$0^{\circ}C$로 유지된 bubbler에 담겨지고 증발된 precursor molecules는 Argon(Ar:99.999%) carrier 가스에 의해 process reactor 내부로 유입된다. Plasma는 RF(13.56MHz generator로 연결된 susceptor 주위에 발생시켰다. Silicon 기판위에 증착한 시편으로 Fourier transform infrared (FTIR) spectra 및 열적 안정성을 측정하였고, Pt 기판위에 증착한 시편으로 Al/유기박막/Pt 구조의 capacitor를 만들어 열적안정성을 측정하였고, Pt 기판위에 증착한 시편으로는 Al/유기박막/Pt 구조의 capacitor를 만들어 K값 및 절연성을 측정하였다. Capacitance는 1MHz 주파수에서 측정하였다. 열적안정성은 30분동안 Ar 분위기에서 annealing하기 전후의 증착막의 두께의 변화를 측정함으로써 조사하였으며 유기박막의 두께는 surface profilometer로 측정하였다. 증착온도가 45$^{\circ}C$에서 15$0^{\circ}C$, 25$0^{\circ}C$로 높아짐에 따라 k값은 높아졌지만 대신 열적안정성은 좋아졌다. plasma power 30W인 경우 45$^{\circ}C$에서 증착했을 때 유전상수는 2.80으로 낮았지만 40$0^{\circ}C$에서 30분 동안 열처리한 후 두께가 49% 감소하였다. 그러나 25$0^{\circ}C$에서 증착했을 때 유전상수는 3.10으로 좀 높아졌지만 열적으로는 40$0^{\circ}C$까지 안정하였으며 45$0^{\circ}C$에서도 두께의 감소는 8%에 불과했다.

• Applied Chemistry for Engineering
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• v.3 no.4
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• pp.694-700
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• 1992

Aromatic polyamides and polyesters with fexible spacers are prepared by Heck reaction with palladium catalysts In presence of carbon monoxide gas. Dichlorobis(triphenyl phosphine) plladium(II) ($PdCl_2(PPh_3)_2$) and palladium chloride ($PbCl_2$) are used as catalysts. Polyamides and polyesters prepared by his polymerization system have similar transition temperatures. Flexible spacer substituted on phenylene units are varied from hexyl to hexadecyl, the length of spacers effected on transition temperatures of substituted polymers.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.265-267
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• 2011

저온 대기압 플라즈마는 21세기에 들어 생의학 분야에 이용될 수 있는 새로운 도구로서 많은 관심을 받고 있다. 대기압 플라즈마는 고가의 진공 장비를 필요로 하지 않고 저전력 구동이 가능하기 때문에 저비용 구동이 가능하고 방전 장치와 전력공급 장치의 소형화에 매우 유리하다. 특히 저온 대기압 플라즈마는 고온의 전자와 저온의 이온 입자가 공존하는 열적 불평형(thermal non-equilibrium) 상태에 있기 때문에 플라즈마의 저온 특성은 유지하면서도 (${\sim}30^{\circ}C$) 물리/화학적 반응성은 매우 높아 그 응용 분야가 매우 넓다. 플라즈마의 다양한 생의학 분야 응용 가운데 세포의 사멸 유발 또는 생장 촉진, 살균/멸균, 지혈, 상처 치유 등에 저온 대기압 플라즈마가 매우 뛰어난 효능을 보인다는 것이 국내외의 다양한 연구를 통해 밝혀지고 있다 [1]. 20 kHz 정현파로 구동되는 플라즈마 장치를 이용한 암 세포 제거 실험에서 플라즈마 처리 효과를 증대시키기 위해 항체-금나노입자 중합체를 암 세포에 주입시켰다 (그림 1(a)). 그 결과 세포의 사멸율은 74%로서 플라즈마 또는 플라즈마-금나노입자만을 처리한 경우에 비하여 사멸율이 매우 높게 나타났다 (그림 1(b)). 이를 통해 암세포 선택성을 가진 항체-금나노입자 중합체와 플라즈마 처리 기술을 융합한 암 세포의 선택적 사멸 유발 기술의 개발 가능성이 열렸다. 또한 플라즈마 처리를 통해 일어나는 세포의 자멸사 기작이 Cytochrome C의 방출 이후 이어지는 Caspase-3의 활성화 경로와 관계가 있음이 밝혀졌다 (그림 1(c)). 치아 미백은 최근 부상하고 있는 저온 대기압 플라즈마의 새로운 응용 분야이다 [5-6]. 대기압에서 동작하는 헬륨 플라즈마 제트를 미백제(과산화수소)와 함께 발치된 치아에 적용하였을 때 (그림 2(a)) 미백제만을 사용하였을 경우에 비해 치아의 색상 변화가 2배 이상 크게 나타나는 것을 확인하였다 (그림 2(b)). 이처럼 최근 그 범위가 크게 넓어지고 있는 저온 대기압 플라즈마의 생의학 응용 기술의 최적화를 위해서는, 다양한 생의학 응용 분야에 따라 요구되는 플라즈마의 특성 및 응용별 기저 기 작에 대한 이해와 연구가 필요하다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.11
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• pp.3060-3065
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• 2009

A series of wholly aromatic Poly(ether-ether-ester)s with flexible side chain was synthesized by direct polycondensation from ether linkaged triad diol and 2,5-dialkoxyterephthalic acid. The chemical structures and physical properties of these polymers were investigated by using $^1H$-NMR, FT-IR, DSC and TGA. As results of investigations, the inherent viscosities($\eta$inh) measured at $40^{\circ}C$ in 1,1,2,2-tetrachloroethane(TCE) were 0.45~0.86 dl/g and initial decomposition(Td) in TGA occurred at 378~418 $^{\circ}C$ in N2 gas. The majority of these polymers were soluble in organic solvents used in this experiments at elevated temperatures. Melting temperatures(Tm) decreased with increasing the length of the side chain and showed odd-even effects.

• Polymer(Korea)
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• v.26 no.1
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• pp.61-70
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• 2002

The effects of molecular weights and rheological properties of polypropylene (PP), on its foam structures in batch process were investigated. The effects of crosslinking process were also considered in this study. The rheological properties of polypropylene, such as storage modulus(G'), loss modulus(G"), zero shear viscosity($\eta_O$), and relaxation time($\lambda$), increased with the increase of molecular weights, and these increases in rheological properties directly affected the stability improvements of the PP foam. The increase of crosslinked PP's gel content stopped at the irradiation dose of 3.2 Mrad. The development of foam structures was more enhanced as the irradiation dose increased up to 3.2 Mrad. When the irradiation dose exceeded 3.2 Mrad, however, it negatively affected the structural development of the foam by diminishing gel contents of the foaming material, which resulted in instability of the foam structure.ture.

• Journal of the Korean Applied Science and Technology
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• v.33 no.4
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• pp.771-776
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• 2016

The acrylate copolymer having good thermal stability, coating and adhesion properties was designed and prepared. We prepared copolymers in >95% high yield using methyl methacrylate, isobornyl methacrylate and 2-hydroxyethyl methacrylate monomers by the bulk and emulsion polymerization techniques. The $^1H$-NMR spectrum was used to identify chemical structure and glass transition temperatures increased from $123^{\circ}C$ to $140^{\circ}C$ confirmed by DSC, DMA and TGA analysis. In addition, as the content of IBMA increased, storage modulus and thermal decomposition temperature increased. As the content of IBMA increased from 10% to 30% in the composition for the entire monomer, tensile strength increased from 22 to 30 MPa in both polymers prepared by bulk and emulsion techniques. The contact angle increased from 70 to up to 88 degrees due to hydrophobic property of IBMA.

• Korean Journal of Food Science and Technology
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• v.22 no.1
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• pp.33-37
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• 1990

A simple and rapid method, based on separation of a flying oil into monomeric, dimeric and oligomeric triglyceride by means of high performance size exclusion chromatography on Ultrastyragel column (500 A), is proposed for evaluation of the quality of used frying oil. The relative area of the monomeric triglyceride was decreased with frying time increase, however, the decrease rate was significantly reduced by treatment of a composited powder (porous rhyorite/citric acid 40/56/4). This measurement showed good linear relationship with change in polar component measurement. There were no significant differences between the slopes of regression lines in both treated and non-treated frying oil system for relationship between monomeric triglyceride and polar component. By this method, it was found that a frying oil habe to be discarded if the content monomeric triglyceride decreased to 71%, which was corresponed to 27% polar component.

• Journal of the Korean Chemical Society
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• v.21 no.3
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• pp.219-224
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• 1977

The free radical initiated copolymerization of vinyl acetate (VAc) and bis(${\beta}$-chloroethyl)vinylphosphonate (BCVP) was studied. The monomer reactivity ratios for the monomer pair determined at $50^{\circ{C$ using benzoyl peroxide as an initiator are: $r_1 (VAc) = 0.33,\;r_2 (BCVP) = 0.47$ The values of Alfrey-Price's Q and e for the bis(${\beta}$-chloroethyl)vinylphosphonate were calculated to be 0.06 and 1.1, respectively. The statistical analyses for the monomer sequence distribution and the mean sequence length show that the copolymer formed from these two monomers are of fairly alternating tendency. Differential thermal analysis showed that thermal stability of the copolymers decreases as the content of BCVP in the copolymer increases.