Extremely sensitive and selective sub-ppm CO detection by the synergistic effect of Au nanoparticles and core–shell nanowires

Kim, Jae-Hun,Mirzaei, Ali,Kim, Hyoun Woo,Kim, Sang Sub Elsevier Sequoia 2017 Sensors and actuators. B Chemical Vol.249 No.-

<P><B>Abstract</B></P> <P>An extremely sensitive CO sensor based on novel hybrid SnO<SUB>2</SUB>–ZnO core–shell (C–S) nanowires (NWs) functionalized by Au nanoparticles (NPs) was synthesized. First, networked SnO<SUB>2</SUB> NWs were successfully prepared using the vapor–liquid–solid growth method on an electrode layer with special patterns. A ZnO shell was subsequently coated on the SnO<SUB>2</SUB> core using atomic layer deposition, and Au NPs were then attached onto the ZnO shell using γ-ray radiolysis. The resulting sensor exhibited a very high response of 26.6–100ppb CO gas. Furthermore, the responses to other gases such as C<SUB>6</SUB>H<SUB>6</SUB> and C<SUB>6</SUB>H<SUB>7</SUB> were extremely low, indicating the very good selectivity of the sensor to CO gas. Besides acting as heterojunctions, the catalytic effect of the Au NPs on CO gas greatly improved the CO sensing capability of the Au-functionalized SnO<SUB>2</SUB>–ZnO C–S NWs. The high sensitivity and selectivity of this sensor can open a path for prompt toxic monitoring and early detection of fatal diseases related to CO.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel hybrid SnO<SUB>2</SUB>–ZnO core–shell nanowires functionalized by Au nanoparticles. </LI> <LI> The resulting sensor exhibited a very high response of 26.6–100ppb CO gas. </LI> <LI> The very good selectivity of the sensor to CO gas. </LI> <LI> Heterojunctions and the catalytic effect of Au greatly improved the CO sensing capability. </LI> </UL> </P>

SPIM 벡터제어를 위한 태양광 발전 시스템

고재섭(Jae-Sub Ko),최정식(Jung-Sik Choi),정병진(Byung-Jin Jung),김도연(Do-Yeon Kim),박기태(Ki-Tae Park),최정훈(Jung-Hoon Choi),정동화(Dong-Hwa Chung) 한국조명·전기설비학회 2007 한국조명·전기설비학회 학술대회논문집 Vol.2007 No.11월

This paper presents the photovoltaic(PV) water pumping system with a maximum power point tracking(MPPT). The water pumping system uses a variable speed single phase induction motor(SPIM) driven a centrifugal pump by field oriented control(FOC) inverter. The MPPT using a DC-DC converter controlled the duty cycle to track maximum power from PV under different insolation conditions. The duty cycle directly relate with a flux producing current control(i<SUB>ds</SUB>). The FOC inverter uses a current control voltage source inverter(CC-VSI). The simulation results are shown that the characteristics and performance of drive system, which varies as each conditions of light by expresses in voltage(V<SUB>dq</SUB>), current(I<SUB>dq</SUB>), speed of motor and torque.

스포츠클럽 참여하는 중학생들의 신체적 자기개념이 학교생활만족도에 미치는 영향

박준억, 박상섭, 정재원 忠北大學校 平生體育硏究所 2015 平生體育硏究所 論文集 Vol.27 No.-

The purpose of this study is to investigate the effect of physical self-concept and school life satisfaction of middle School students participating in sports clubs. To achieve this purpose, male and female middle school students participating in sports clubs in the C area in 2015 using a convenience sampling method were aimed to collect data. The data was subjected to factor analysis, reliability analysis and correlation and regression analysis using the SPSS 19.0 program, The results are as follows. First, the fitness had significant influence among physical self-concepts of the sub-factors on satisfaction school life satisfaction, teacher relationships, and physical behavior. Secondly, the flexibility, of the sub-factors among physical self-concepts of sub-factors had significant influence on the subordinate relationship between teachers which is the sub-factors of school life satisfaction. Third, the health, and appearance, among physical self-concepts of sub-factors had significant influence on the physical environment of sub-factors of the school life satisfaction.

Haplogroup Classification of Korean Cattle Breeds Based on Sequence Variations of mtDNA Control Region

Kim, Jae-Hwan,Lee, Seong-Su,Kim, Seung Chang,Choi, Seong-Bok,Kim, Su-Hyun,Lee, Chang Woo,Jung, Kyoung-Sub,Kim, Eun Sung,Choi, Young-Sun,Kim, Sung-Bok,Kim, Woo Hyun,Cho, Chang-Yeon Asian Australasian Association of Animal Productio 2016 Animal Bioscience Vol.29 No.5

Many studies have reported the frequency and distribution of haplogroups among various cattle breeds for verification of their origins and genetic diversity. In this study, 318 complete sequences of the mtDNA control region from four Korean cattle breeds were used for haplogroup classification. 71 polymorphic sites and 66 haplotypes were found in these sequences. Consistent with the genetic patterns in previous reports, four haplogroups (T1, T2, T3, and T4) were identified in Korean cattle breeds. In addition, T1a, T3a, and T3b sub-haplogroups were classified. In the phylogenetic tree, each haplogroup formed an independent cluster. The frequencies of T3, T4, T1 (containing T1a), and T2 were 66%, 16%, 10%, and 8%, respectively. Especially, the T1 haplogroup contained only one haplotype and a sample. All four haplogroups were found in Chikso, Jeju black and Hanwoo. However, only the T3 and T4 haplogroups appeared in Heugu, and most Chikso populations showed a partial of four haplogroups. These results will be useful for stable conservation and efficient management of Korean cattle breeds.

셀룰로스계 혼화제를 사용한 수중불분리성 콘크리트의 최적 배합

진치섭,엄장섭,박현재,윤재환 부산대학교 생산기술연구소 2001 生産技術硏究所論文集 Vol.60 No.-

수중불분리성 콘크리트는 통상적인 수중 콘크리트와는 개념부터 다르다. 콘크리트에 수중불분리성 혼화제를 혼합하면 콘크리트의 점성이 증가되고 수중에서의 재료분리에 대한 저항성이 현저히 증가된다. 이 효과는 수중콘크리트 자체의 신뢰성을 높여줄 뿐만 아니라 타설지역의 환경보존에도 현저한 기여를 하게 된다. 본 연구에서는 셀룰로스계 수중불분리성 혼화제 (수용성 셀룰로스 에틸계)와 고유동화제 (고축합 트리아진계)의 첨가량 변화에 따른 수중불분리성 콘크리트의 제반 물성 변화를 검토하고 비교적 정온 상태의 해상 환경에 적용할 수 있는 수중불분리성 콘크리트의 치적 배합을 결정하였다. Antiwashout underwater concrete is quite different in concept from conventional underwater concrete. By mixing an antiwashout admixture with concrete, the viscosity of the concrete is increased and its resistance to segregation under the washing action of water is enhanced. The effect of this is not only to greatly improve the reliability of concrete placed under water, but it also has remarkable effects on environmental preservation in the construction area. In this study, property tests of antiwashovt underwater concrete have been carried out, as variable add of special admixture, i.e antiwashout underwater agent (Hydroxy Ethyl Cellulose), superplasticizer (High condensate Tri - Azine). We made the antiwashout underwater concrete have enough strength to endure with easy construction. And we have decided the optimal mix proportion far antiwashout underwater concrete under standard state.

A sub-1-volt nanoelectromechanical switching device.

Lee, Jeong Oen,Song, Yong-Ha,Kim, Min-Wu,Kang, Min-Ho,Oh, Jae-Sub,Yang, Hyun-Ho,Yoon, Jun-Bo Nature Pub. Group 2013 Nature nanotechnology Vol.8 No.1

<P>Nanoelectromechanical (NEM) switches have received widespread attention as promising candidates in the drive to surmount the physical limitations currently faced by complementary metal oxide semiconductor technology. The NEM switch has demonstrated superior characteristics including quasi-zero leakage behaviour, excellent density capability and operation in harsh environments. However, an unacceptably high operating voltage (4-20 V) has posed a major obstacle in the practical use of the NEM switch in low-power integrated circuits. To utilize the NEM switch widely as a core device component in ultralow power applications, the operation voltage needs to be reduced to 1 V or below. However, sub-1 V actuation has not yet been demonstrated because of fabrication difficulties and irreversible switching failure caused by surface adhesion. Here, we report the sub-1 V operation of a NEM switch through the introduction of a novel pipe clip device structure and an effective air gap fabrication technique. This achievement is primarily attributed to the incorporation of a 4-nm-thick air gap, which is the smallest reported so far for a NEM switch generated using a 'top-down' approach. Our structure and process can potentially be utilized in various nanogap-related applications, including NEM switch-based ultralow-power integrated circuits, NEM resonators, nanogap electrodes for scientific research and sensors.</P>

Clinical Manifestations and Treatment Outcomes of Eosinophilic Gastroenteritis in Children

Jong Sub Choi,Shin Jie Choi,Kyung Jae Lee,Ahlee Kim,Jung Kyung Yoo,양혜란,문진수,장주영,고재성,강경훈 대한소아소화기영양학회 2015 Pediatric gastroenterology, hepatology & nutrition Vol.18 No.4

Purpose: The aim of the present study was to investigate the clinical features and outcome of eosinophilic gastro-enteritis (EGE) in children.Methods: Our study enrolled 24 children who were diagnosed with EGE from 1993 to 2014 at the Department of Pediatrics, Seoul National University Children’s Hospital. The patients’ clinical manifestations, treatments, and out-comes were reviewed from the medical records.Results: The mean age at diagnosis was 5.3 years. Most patients had gastrointestinal symptoms including diarrhea (54.2%) and abdominal pain (45.8%). Peripheral eosinophilia was present in 91.7% of the patients. Thirteen patients (54.2%) showed anemia, and 15 patients (62.5%) had hypoalbuminemia. EGE was classified as mucosal, sub-serosal, or muscular in 75.0%, 20.8%, and 4.2% of cases, respectively. Three patients showed gastroduodenal ulcers upon endoscopic analysis. A history of allergy was reported in 13 patients, including atopic dermatitis, allergic rhinitis, and asthma. Five patients (20.8%) improved with food restrictions. Among the 19 patients treated with steroids, 11 (57.9%) discontinued steroid treatment without subsequent relapse, 4 (21.1%) relapsed after ceasing steroid treat-ment, and 4 (21.1%) showed no response to steroids. Two patients who were resistant to steroids underwent ther-apeutic surgery. The presence of gastroduodenal ulcers was significantly associated with relapse and steroid resistance.Conclusion: A high suspicion of EGE is warranted when children have nonspecific gastrointestinal symptoms and peripheral eosinophilia. Most patients improved with food restrictions or steroid treatment, although one-third of pa-tients showed a relapse or steroid resistance.

다차원 특징 및 가중블록 투표방식을 이용한 얼굴 인식 성능 향상 기법

장재윤(Jae-Yoon Jang),윤호섭(Ho-Sub Yoon) 대한전자공학회 2015 대한전자공학회 학술대회 Vol.2015 No.6

This paper proposes novel block voting measure for improving user face recognition system performance. In order to exploit sample’s global and local characteristic, We use various feature and make large dimension feature by concatenation. After then, compare gallery set with probe image. In this step, we divide feature into some block, and recognize each block using cosine similarity. And we obtain probe image class using weighted voting which calculated by block recognition result. This proposed method has advantage that is robustness for noise or outlier data. Because this method depend on the number of sub-block, if enough sub-blocks are guaranteed, it can make improved performance on face recognition system.

Acute and Sub-chronic Oral Toxicity Study of Ammonium Persulfate in Spraque-Dawley Rats

Yong Soon Kim,Min Won Baek,Jae Hyuck Sung,Hyun Youl Ryu,Jin Sik Kim,Hyun Sun Cho,Byung Gil Choi,Min Sub Song,Moon Yong Song,Eun Ju Baik,Young Kuk Choi,Jong Kyu Kim,Il Je Yu,Kyung Seuk Song 한국독성학회 2009 Toxicological Research Vol.25 No.3

The toxicity test of ammonium persulfate was conducted to ensure of its potential toxic effects according to the single-dose acute oral toxicity study (OECD Guideline 423) and 90-day repeated dose sub-chronic oral toxicity study guideline (OECD Guideline 408) for establishing national chemical management system, and matching in the Globally Harmonized Classification System (GHS) category. In acute oral toxicity study, pasty stool, perineal contamination and temporary body weight decrease were observed after dosing 1st and 2nd challenge (300 ㎎/㎏ body weight). All test animals were dead within 6 hours after dosing at 3rd challenge (2000 ㎎/㎏ body weight). Therefore, the GHS class of test substance is considered class 4. In sub-chronic toxicity study, body weight changes, food consumptions, hematological, biochemical and pathological examination did not show any noticeable and significant differences between the administered (5, 20, 80 ㎎/㎏ body weight) and control (vehicle only) group animals. Based on these results, the no observed adverse effect level (NOAEL) is considered above 80 mg/kg body weight.

Acute and Sub-chronic Oral Toxicity Study of Ammonium Persulfate in Spraque-Dawley Rats

Kim, Yong-Soon,Baek, Min-Won,Sung, Jae-Hyuck,Ryu, Hyun-Youl,Kim, Jin-Sik,Cho, Hyun-Sun,Choi, Byung-Gil,Song, Min-Sub,Song, Moon-Yong,Baik, Eun-Ju,Choi, Young-Kuk,Kim, Jong-Kyu,Yu, Il-Je,Song, Kyung-Se Korean Society of ToxicologyKorea Environmental Mu 2009 Toxicological Research Vol.26 No.3

The toxicity test of ammonium persulfate was conducted to ensure of its potential toxic effects according to the single-dose acute oral toxicity study (OECD Guideline 423) and 90-day repeated dose sub-chronic oral toxicity study guideline (OECD Guideline 408) for establishing national chemical management system, and matching in the Globally Harmonized Classification System (GHS) category. In acute oral toxicity study, pasty stool, perineal contamination and temporary body weight decrease were observed after dosing 1st and 2nd challenge (300 mg/kg body weight). All test animals were dead within 6 hours after dosing at 3rd challenge (2000 mg/kg body weight). Therefore, the GHS class of test substance is considered class 4. In sub-chronic toxicity study, body weight changes, food consumptions, hematological, biochemical and pathological examination did not show any noticeable and significant differences between the administered (5, 20, 80 mg/kg body weight) and control (vehicle only) group animals. Based on these results, the no observed adverse effect level (NOAEL) is considered above 80 mg/kg body weight.