• Journal of the Korean Society of Food Science and Nutrition
• /
• v.32 no.5
• /
• pp.655-660
• /
• 2003

Flavor components of dry shrimp, roasted-dry shrimp and roasted-dry shrimp with corn oil (w/w: 10%, 25%) were investigated to evaluate the effects of added corn oil on the formation of volatile components in dry shrimp during roasting process. The identified volatile included 20 nitrogen-containing compounds (7 pyrazines, 7 pyridines 3 pyrroles, others) 14 aldehydes, 5 alcohols, 4 ketones and 11 others. The largest quantities of lipid-derived products hexanal, nonanal, 2-pentylfuran, 1-octen-3-ol, trans-2-decenal, trans, cis-2,4-decadienal, trans, trans-2,4-decadienal were detected in the roasted-dry shrimp samples with corn oil. The lipid-derived aldehydes might be involved in the formation of 3- ethyl-2,5-dimethylpyrazine, 2,3,5-trimethyl-6- ethylpyrazine, 2-ethyl-5,6-dimethylpyrazine, 2,3,5- trimethylpyrazine, 3- ethyl-2,6-dimethylpyridine, 2-propylpyridine, ben-zopyrrole and the others. The nitrogen-containing compounds seem to be a major flavor component and responsible for characteristic flavor in roasted-dry shrimp with corn oil.

• Journal of Sensor Science and Technology
• /
• v.10 no.2
• /
• pp.125-133
• /
• 2001

Conducting polymer sensors show high sensitivity when exposed to volatile organic compounds gases at room temperature. The 8 sensor array using by polypyrrole and polyaniline has been fabricated by chemical polymerization for measuring sensing characteristics of VOCs gases. Conducting polymer was polymerized by using distilled pyrrole, aniline as a monomer and ammonium persulfate (APS) as an oxidant and dodecylbenzene sulfonic acid (DBSA) as a dopant. Dedoped film was synthesized by reverse voltage and redoped film was synthesized by using 1-octanesulfonic acid sodium salt as another dopant in electrochemical cell. The sensitivity and reversibility were influenced by doping, dedoping, redoping and thickness for the polypyrrole and polyaniline. We investigated the relation between the structure of conducting polymer and sensitivity of these sensors through the analysis of scanning electron microscope (SEM), scanning probe microscope (SPM) and $\alpha$-step.

• Korean Journal of Food Science and Technology
• /
• v.27 no.5
• /
• pp.736-741
• /
• 1995

This study was conducted to investigated the change of volatile flavor components of Cassia tora seeds during roasting treatments. The flavor components of Cassia tora seeds were analyzed by gas chromatography(GC) and combined gas chromatography-mass spectrometry(GC/MS). Among the flavor compounds collected by simultaneous steam distillation and extraction(SDE) method, 38 components were separated and identified. They consisted of 3 pyrazines, 4 pyrroles or pyridine, 4 alcohols, 11 aldehydes or ketones, 9 furans or phenols and 7 others. The flavor compounds collected from unroasted Cassia tora seeds were 7 components. During roasting process, many other flavor components were formed and increased in their contents. The contents of pyrazines and furans were highest and increased conspicuously, whereas, the contents of aldehydes, ketones, alcohols and pyridines were not increased significantly.

• Korean Journal of Food Science and Technology
• /
• v.34 no.5
• /
• pp.751-756
• /
• 2002

For the development of functional jang-products, kanjang was prepared using barley bran. Optical density of barley bran kanjang was significantly high at 15 days after fermentation, and the amount of extract was $2{\sim}3$ fold higher than that of soybean kanjang. Among the flavor components identified in barley bran kanjang, the content of 2-furancarboxaldehyde was the highest, followed by 4-vinyl-2-methoxy-phenol, benzene-acetaldehyde, palmitic acid, and methyl-9,12-octadecadienoate. In barley bran and soybean mixtare (1 : 1) kanjang, the content of 2-furancarboxaldehyde was the highest, followed by benzeneacetaldehyde, diethyl phtalate, palmitic acid, and 2-chloroethyl linoleate. Flavor components detected in both barley bran kanjang and barey bran and soybean mixture kanjang were 2-furancarboxaldehyde, benzaldehyde, benzeneacetaldthyde, 4-vinyl-2-mehtoxy-phenol, 1-furfuryl-2-formy pyrrole, dimethyl-1,2-benzenedicarboxylate, diethyl phtalate, palmiticacid, dibutyl-1,2-benzenedicarboxylate, and di-(2-ethylhexyl)phthalate.

• Journal of Adhesion and Interface
• /
• v.2 no.2
• /
• pp.1-10
• /
• 2001

Silica for Epoxy Molding Compound (EMC) was coated via plasma-polymerization with RF plasma (13.56 MHz) as a function of treatment time, power and pressure. 1,3-diaminopropane, allylamine, pyrrole, 1,2-epoxy-5-hexene, allylmercaptan or allylalcohol were utilized for plasma polymerization coating and adhesion of coated silica was evaluated by measuring flexural strength. CTE and water absorption of EMC were also measured, and fracture surface of flexural specimen was analyzed by SEM in order to elucidate the failure mode. The plasma polymer coated silica was analyzed by FT-IR and reactivity of plasma polymer coating with epoxy resin was evaluated with DSC in order to investigate the adhesion mechanism. The EMC prepared from the silica coated with 1,3-diaminopropane or allylamine exhibited high flexural strength, low CTE, and low water absorption compared with the control sample, and also exhibited 100% cohesive failure mode. These results can be attributed to the chemical reaction between the functional groups in the plasma polymer coating and epoxy resin, and also consistent with the results from FT-IR and DSC analysis.

• Journal of Conservation Science
• /
• v.37 no.3
• /
• pp.245-254
• /
• 2021

In this study, organic materials in Dancheong specimens were analyzed to establish a Dancheong preparation method in Unhangak Hall of Hwaryeongjeon Shrine, Suwon. IR and pyrolysis/GC/MS were applied to a Zuhong specimen and a gilded one. The IR spectra showed absorption peaks corresponding to C-O, C=O, OH, although they were different from those of animal glue, Asian lacquer, and drying oil. The Pyrolysis/GC/MS after the on-line methylation revealed Asian lacquer-derived components, such as methyl 7-(2,3-dimethoxyphenyl)heptanoate, and drying oil-derived components, such as nonanedioic acid, dimethyl ester. Based on these results, we estimated that Asian lacquer and drying oil were used in the Dancheong preparation. Small amounts of 3-methyl-1H-pyrrole were also detected, which could possibly originate from animal glue. The radiocarbon age of the specimens appeared to be between the late 17^th to the early 20^th century. This study potentially reports the first case of Asian lacquer detection in a Dancheong specimen in Korea.

• Proceedings of the KIEE Conference
• /
• 1999.07d
• /
• pp.1660-1663
• /
• 1999

혈액 내의 요소 농도는 신장병 진단의 척도로서 정확한 측정이 필요하다. 요소의 농도는 전위차법을 이용하여 정확히 검출할 수 있으며 이를 위하여 효소를 고정화시킨 전극형 센서를 사용하였다. 전도성 고분자로서 P3MT(Poly(3-methylthiophene) )와 PPy(polypyrrole)를 효소 고정화에 이용하였다. PPy는 전기적 특성이 좋고 중합 및 효소의 고정화가 용이하며 중합 과정이 상대적으로 신속하고 비용도 저렴하다는 장점은 있으나. 다소 불안정하다. P3MT는 PPy와 마찬가지로 전극 상에 단량체가 전기적 산화에 의하여 중합되고 일반적으로 전해질 이온이 도우핑된 상태나 도우핑 되지 않은 상태 모두에서 산소. 습도. 온도에 대하여 매우 안정하다. 본 연구에서는 3-methylthiophene과 pyrrole을 전기 중합하여 urease를 고정화한 요소센서의 특성(감도, 안정성, 직선성)을 비교하였다. P3MT를 이용한 센서와 PPy를 이용한 센서 각각에 대해 감도는 P3MT가 32.3mV/decade, PPy가 4.7mV/decate로서 P3MT가 우수하였고 직선성도 보다 뛰어났으며 순환 전압 전류 곡선을 분석한 결과 P3MT가 PPy보다 안정성도 우수한 특성을 보였다.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.354.2-354.2
• /
• 2016

Mycosporine-like amino acids (MAAs) are small secondary metabolites produced by organisms that live in environments with high volumes of sunlight, is an important group of novel bioactive compounds having immense biotechnological poten-tials due to their UV screening properties and Polypyrrole (PPy) is a type of organic polymer formed by polymerization of pyrrole. A novel composite nanofilm (~60 nm) of mycosporine-like amino acid (MAA) and polypyrrole is synthesized by interfacial polymerization technique. This composite nanofilm is conductive and has strong photoresponse. A photoelectric UV sensor is fabricated by depositing the composite film onto a silicon chip. This UV sensor shows good sensitivity, selectivity and stability for UV detection.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.432.2-432.2
• /
• 2016

A new A-D-A type (Acceptor-Donor-Acceptor) conjugated based on pyridine-borane complex (Donor), non-boron fluorine (Donor) and 2,5-bis(alkyl)-3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (DPP) (Acceptor) were designed and synthesized via Pd-catalyzed Suzuki cross-coupling reaction. The synthesized boron based complex exhibited high electron affinity, which indicates deep HOMO energy levels and good visible absorption led to their use as donors in BHJ (bulk heterojunction) solar cells. Inverted devices were fabricated, reaching open-circuit voltage as high as 0.91eV. To probe structure-property relationship and search for design principle, we have synthesized pyridine-boron based electron donating small molecules. In this study, we report a new synthetic approach, molecular structure, charge carrier mobility and morphology of blended film and their correlation with the photovoltaic J-V characteristics in details.

• Journal of Sensor Science and Technology
• /
• v.23 no.6
• /
• pp.383-387
• /
• 2014

Electrically conductive polypyrrole-polyvinylpyrrolidone (PPy-PVP) nanofiber mats with a core-shell structure have been successfully fabricated by a two-step process: the formation of FeCl3-containing PVP nanofiber mat by electrospinning, and the vapor-phase polymerization (VPP) of pyrrole monomer on the mat in a sealed chamber at room temperature. Surface morphology and chemical composition of the PPy-PVP mat were characterized by SEM, EDX and FTIR analyses. The as-prepared nonwoven mat was composed of PPy-PVP nanofibers with an average diameter of 300 nm. The sheet conductivity of the nanofiber mat was measured to be approximately 0.01 S/cm by a four-point probe. We have also investigated gas-sensing properties of PPy-PVP nanofiber mat upon exposure to methanol vapor. The PPy-PVP nanofiber sensors were observed to have excellent methanol-sensing performance. The nanofiber-based core-shell nanostructure could give an opportunity to fabricate a highly sensitive and fast response sensor due to its high surfaceto-volume ratio.