Effect of Film Thickness on Sensitivity for PVA-based Microwave Humidity Sensor

최부철,권영환,여준호 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-

Relative humidity (RH) is an important environmental parameter along with temperature to assess the quality of air, and polyvinyl alcohol (PVA) has been used in microwave frequencies as a high-sensitivity polymer material for RH sensing. In this paper, the effect of film thickness on the sensitivity for a PVA-based microwave humidity sensor was investigated. A high-sensitivity meander-line slot (MLS)-loaded microstrip patch sensor antenna (MPSA) was designed and fabricated on a 0.76 mm-thick RF-35 substrate to resonate at 2.5 GHz under unloaded conditions. Three different PVA films with different thickness were coated on top of the MLS resonator of the MPSA, and their sensitivities for varying RH from 40% to 80% with a step of 10% were compared, by measuring the shift in the resonant frequency of the input reflection coefficient characteristic.

Study on Preparation and Property of Silicone Composites based on Silane Modified TiO₂ Inorganic Particles

곽보민,최부철,서민영,정수란,권영환 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-

TiO₂ particles have excellent properties such as good stability, high refractive index, hydrophilicity, UV resistance and excellent transparency for the visible light. This study investigates the effect of different TiO₂ filler contents on the mechanical properties of silicone/TiO₂ composites, where surface-modified TiO₂ particles using vinyl-trimethoxy silane are used. The silicone/TiO₂ composites with the mass fraction of TiO₂ particles up to 20% was prepared by bulk mixing method and showed the mechanical enhancement with increasing the surface-modified TiO₂ content.

Thermal Conductivity and Mechanical Properties of Silicone Polymer Composites Containing Graphene Particles

곽보민,최부철,서민영,정수란,권영환 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-

Great attention has been paid on the use of carbon materials for increasing thermal conductivity of polymers due to their unique nanostructures, high aspect ratio and superior thermal conductivity. Graphene has been recognized as one of the best carbon materials for this purpose due to its excellent thermal conductivity. This study is to investigate the effect of graphene filler on the thermal conductivity and mechanical properties of silicone/graphene composite. The silicone/graphene composites with the mass fraction in the range of 0.1% ~ 1% of graphene fillers were prepared by bulk mixing method. In addition, surface-modified graphene fillers were also used to examine the effect of dispersion of graphene fillers on the thermal conductivity.

Survey of Mycotoxins in Commonly Consumed Korean Grain Products Using an LC-MS/MS Multimycotoxin Method in Combination with Immunoaffinity Clean-up

정소영,최부철,최은정,정희정,황영숙,신기영,김정훈 한국식품과학회 2015 Food Science and Biotechnology Vol.24 No.4

A total of 47 powder of roasted grain (sunsik) samples were collected from markets in Seoul, Korea for a survey of mycotoxin contaminants. A multitoxin immunoaffinity column was used to clean-up extracts for all mycotoxins. An LC-MS/MS method was used to perform simultaneous quantitative determination of aflatoxins (B1, B2, G1, and G2), deoxynivalenol, fumonisin (B1, B2), ochratoxin, zearalenone, T-2, and HT-2 in sunsik samples. Limits of detetction (LOD) and quantitation (LOQ) for mycotoxins ranged 0.1-6.1 and 0.3-18.4 μg/kg, respectively. Zearalenone was detected in all sunsik samples, deoxynivalenol was detected in 38.3% of sunsik samples, ranging from 0.63 to 29.3 μg/kg and not detected (ND)-48.3 μg/kg, respectively. The daily intake values of mycotoxins from sunsik for the p95 quartile for Korean consumers were 0.42% (DON), 0.12% (FBs), 0.42% (OTA), and 1.87% (ZEA) of TDI.

서울지역 음식점 메뉴의 나트륨 및 칼륨 함량 비교

장미라,홍미선,최부철,한성희,이경아,김리라,이집호,김정헌,정권 한국식품위생안전성학회 2015 한국식품위생안전성학회지 Vol.30 No.2

To determine the contents of sodium (Na) and potassium (K) for restaurant dishes, 194 cases classified 26 kinds of restaurant dishes were collected from restaurants in Seoul and were analysed using the atomic absorption spectroscopy. Average contents of Na and K in Kimchi among restaurant dishes were highest as 554.9±155.5 mg/100g, 225.1±69.1 mg/100g, while average contents of Na and K were lowest in Seolleongtang as 24.2±5.8 mg/100g, 12.7±3.9 mg/100g respectively. The contents between Na and K in restaurant dishes had a strong correlation of positive linear judging from 0.782 (p-value<0.01) of the correlation coefficient. The Na/K ratio of Bulgogi was appropriate as 1.17±0.44, while those of Udon, banquet noodles, Kalguksu were very high as shown more than 10. The contents of Na and K were examined 5 dish groups as Gook/Tang, Jjigae/Jeongol, stir-fried dish, noodle and Kimchi. Average contents of Na and K classified by dish groups were significantly difference (p-value<0.001). Average content of Na among dish groups was highest in Kimchi as 554.9±155.5 mg/100g followed by Jjigae/Jeongol, Gook/Tang, stir-fried dish and noodle. Similar to Na content, average content of K was highest in Kimchi as 225.1±69.1 mg/100g followed by stir-fried dish, Jjigae/Jeongol, Gook/Tang and noodle. The ratio of Na/K by classified groups of dishes was shown as significantly difference (p-value<0.001). Stir-fried dish was 1.18±0.44 close to 1 followed by Kimchi, Jjigae/Jeongol, Gook/Tang, and noodle.

계절별 다소비식품 중 무기영양원소 함량 평가

이경아,장미라,김욱희,박영애,최부철,한성희,김리라,김진경,이집호,황인숙,오영희,정권 한국식품위생안전성학회 2017 한국식품위생안전성학회지 Vol.32 No.2

The purpose of this study was to determine the sodium (Na) and potassium (K) content of seasonal foods Four hundred food samples classified into 8 different kinds of seasonal foods were collected from 150 restaurants located in Seoul. The Na and K content in seasonal foods were the analyzed by ICP-OES. The Average content of Na and K in spicy seafood noodle soup were highest as 391.4 ± 72.7 mg / 100 g and 88.6 ± 21.4 mg / 100 g, respectly, while average content of Na was lowest in spicy buckwheat noodles as 255.3 ± 67.0 mg / 100 g and the average content of K was lowest in Udon as 36.3 ± 17.8 mg / 100 g, respectively. The Na/K ratio of spicy buckwheat noodles was 3.2 ± 1.0, while those of cold buckwheat noodles, fish cake, Udon were very high as measured more than 8. Among the seasonal foods, the average content of Na was highest in Winter group as 366.9 ± 81.8 mg / 100 g and the average content of K was highest in Autumn group as 84.8 ± 24.1 mg / 100 g. The ratio of Na/K was lowest in Summer group as 5.9 ± 3.3.

GC-NPD 동시분석법을 이용한 유니코나졸 잔류실태조사

김은정(Eun-Jeung Kim),최부철(Bu-Chuhl Choi),최수정(Su-Jeong Choi),홍채규(Chae-Kyu Hong),김은희(Eun-Hee Kim),최재만(Chae-Man Choi),서영호(Young-Ho Seo),황영숙,장미라(Mi-Ra Jang),황인숙(In-Sook Hwang),김무상(Moo-Sang Kim),채영주(Young-Zoo 한국식품과학회 2012 한국식품과학회지 Vol.44 No.3

2011년 6월부터 11월까지 농산물 중 GC-NPD 및 GC-MSD를 이용한 동시 다성분 분석법을 이용하여 uniconazole의 잔류실태조사를 실시하였다. 2011년 6월부터 11월까지 서울지역에 유통되고 있는 농산물 121종 총 3,939건에 대하여 잔류실태조사를 실시한 결과 49건에서 uniconazole이 검출되었다. 품목별로는 겨자채가 69.4%로 가장 많이 검출되었다. Uniconazole의 검출양은 0.09 ㎎/㎏에서 17.89 ㎎/㎏로 나타났다. 본 연구에서는 uniconazole에 대하여 GC-NPD 및 GC-MSD를 이용한 동시분석법의 가능성을 검토하였다. GC-NPD의 검출한계와 정량한계는 각각 0.006 ㎎/㎏와 0.018 ㎎/㎏이었다. 겨자채에 표준용액을 0.5, 5 ㎎/㎏ 농도로 하여 회수율을 측정한 결과 83.4%에서 101.4%까지 양호한 결과를 나타내었다. 본 연구를 통하여 동시분석법으로 보다 효율적인 검사가 가능할 것으로 기대된다. The monitoring of the uniconazole residual pesticide for agricultural products was conducted by multiclass pesticide multiresidue methods. Samples were collected from June to November, 2011. Uniconazole pesticide was detected in 49 samples from a total of 3,939 samples. The amount of uniconazole pesticide ranged from 0.09 to 17.89 ㎎/㎏ in 49 samples. This method was described for the simultaneous determination of uniconazole by gas chromatography with a nitrogen phosphorus detector (GC-NPD) and mass spectrometry (MS). The limit of detection and quantification were 0.006 and 0.018 ㎎/㎏ GC-NPD, respectively. For an evaluation of the GC-NPD method, uniconazole spiked into gyeojachae at a level of 0.5, 5 ㎎/㎏ was determined. The recoveries of uniconazole by the GC-NPD method ranged from 83.4 to 101.4%. The results indicate that the method of simultaneous analysis is applicable to uniconazole analysis.

어린이기호식품 중 당류 및 당알코올류 함량분석

금진영,홍미선,장미라,최부철,이경아,김일영,김정헌,채영주 한국식품위생안전성학회 2014 한국식품위생안전성학회지 Vol.29 No.3

In this study, HPLC-RI was used to determine sugars and sugar alcohols contents in 102 differentkinds of processed foods met to children's taste. The average amount of sugars per 100 g of candies was 70.25 g, ofprocessed cocoa products was 65.34 g, of processed chocolate products was 47.53 g, of breads was 25.66 g, of cookieswas 22.28 g, of ices was 12.47 g, of snacks was 9.74 g. Processed cocoa product items had relatively higher sucrosecontents (56.80 g/100 g) than any other items. The average amount of sucrose per 100 g of candies was 44.20 g, ofprocessed chocolate products was 32.89 g, of breads was 23.11 g. When the contents of sugars in processed foods metto children's taste per on serving size were compared to WHO guidelines, the percentages were 5.84~28.52 about recommendeddaily intake of total sugar of 50 g. The result for the analysis of confectioneries showed that 13 samples of102 were detected and the sugar alcohols content of samples investigated varied between 0.01~15.06%.

식용유지류 중 벤조피렌의 함량 분석 및 안전성 평가

장미라,홍미선,정소영,최부철,이경아,금진영,김일영,김정헌,채영주 한국식품위생안전성학회 2014 한국식품위생안전성학회지 Vol.29 No.2

To assess the health risk for benzo(a)pyrene by the intake of edible oils, 288 cases of edible oilscollected from food markets were analysed using the high performance liquid chromatography with fluorescencedetector. The levels of benzo(a)pyrene were from non-detection to 4.78 μg/kg, and the average was 0.11 μg/kg. Thechronic daily exposures of benzo(a)pyrene for total population group and consumer-only group were estimated usingthe food consumption data in the fifth Korea National Health and Nutrition Examination Survey in 2011. The estimateddaily intake of benzo(a)pyrene was 4.26 × 10−3 ng/kg b.w./day for total population group and 7.64 × 10−3 ng/kgb.w./day for consumer-only group. The MOE (margin of exposure) of benzo(a)pyrene for total population group andconsumer-only group was 7.28 × 107~1.74 × 108 and 3.95 × 107~9.42 × 107, respectively. Accordingly, the health riskfrom benzo(a)pyrene caused by the intake of edible oils was considered as a very low level.

수입 과일에 살포된 수확 후 처리농약(Post-harvest pesticide)의 경시적 변화

황래홍,조태희,조인순,엄정훈,박영혜,최부철,김현정,김정헌 한국식품위생안전성학회 2010 한국식품위생안전성학회지 Vol.25 No.3

The post-harvest concentration change of four kind of pesticides, captan, chlorpyrifos, methidathion and kresoxim-methyl was investigated with the storage period for the import fruit. Then the post-harvest concentration was set to 1000, 250, 400 and 157 mgkg−¹ for captan, chlorpyrifos, methidathion and kresoxim-methyl respectively. In case of captan, 0.9-12.5 mgkg−¹ in total fruit base and ND-0.23 mgkg−¹ in the sarcocarp were measured after atomization and 0.7-3.2 mgkg−¹ in total fruit base and ND-0.67 mgkg−¹ in the sarcocarp were measured after four week. For chlopyrifos, menthidathion, and kresoxim-methyl 0.4-2.2, 0.7-3.1 and 1.3-2.1 mgkg−¹ in total fruit base and ND-0.32, ND-0.05 and ND-0.16 mgkg−¹ in the sarcocarp were measured after atomization respectively. After four week 0.3-0.9, 0.4-2.0 and 1.3-1.8 mgkg−¹ in total fruit base and ND-0.02, ND-0.05 and ND-0.15 mgkg−¹ in the sarcocarp were investigated for other three pesticides. The concentration decreasing ratio of pesticides was largest for captan,52% and other components were in order of chlopyrifos, menthidathion, and kresoxim-methy, 47, 41, 11% each other.