PASS (polyamic acid alkylamine salts) LB막의 유전 특성

강도열,김태완,박준수 弘益大學校 科學技術硏究所 1994 科學技術硏究論文集 Vol.4 No.-

Dielectric properties of PAAS LB films were studies in a frequency range of 10 Hz to 13 MHz. Y-type films were made under a surface pressure of 30mN/m using Kuhn type apparatus. It was found that there is a dielectric dispersion of electric polarization near 105 Hz. The effect of electric polarization was also confirmed by charging and discharging current under an application of dc voltage.

복막유착의 원인 규명과 예방을 위한 실험적 연구

강대영,송규상,노승무,조준식,이태용 충남대학교 의과대학 지역사회의학연구소 1999 충남의대잡지 Vol.26 No.1

Postoperative peritoneal adhesion is the most common cause of intestinal obstruction, and intestinal obstruction is one of the most difficult problems in abdominal surgery. In this experimental study for developing peritoneal adhesion model and its prevention, we divided rats into 5 groups; the talc powder treated group, the cotton-fluff treated group, the talc+fluff treated group, the ischemia group and the control group. There were 16 rats in each group. We made incisions on the midabdomen of the rats and administered talc powder, cotton fluff and talc powder+fluff into the peritoneal cavity respectively. In the ischemia group, we clamped the root of superior mesenteric artery for two minutes to induce ischemia on the small bowel of the rat. We counted the number of the peritoneal adhesive sites in peritoneal cavity on the 7th, 14th , 21st and 42nd postoperative day after peritoneal adhesion induced operation, and observed the characters of the adhesion state. The average number of the peritoneal adhesions were 1.25 per one rat in the talc powder group, 1.44 in the fluff group, 1.31 in the talc+fluff group and 1.31 in the ischemia group compared with 0.94 per one rat in the control group performed sham operation. 91.6% of the all adhesions were observed on the peritoneum of the previous incision sites and only 8.4% of the adhesions were adhered to the peritoneal surface of non-incision sites. The data of this study suggest that peritoneal injury and inflammatory reaction is the major cause of peritoneal adhesion. Also this study indicates that foreign bodies can develop peritoneal adhesion, but the effect is much lower than that of peritoneal injury with inflammatoty reaction.

산재지정병원 이용 후 산재요양환자에 대한 만족도 조사

이화평,임형준,주영수,권영준,강희태,김정민,조성식,이태경,윤종완 대한산업의학회 2007 대한직업환경의학회지 Vol.19 No.3

일개 제빵회사 근로자의 제빵공 천식 유병률

김정민,권영준,주영수,임형준,이태경,강혜련,백도명 大韓産業醫學會 2008 대한직업환경의학회지 Vol.20 No.3

목적: 일개 제빵회사에서 제빵공 천식 유병률을 조사하여 제빵공 천식으로 인한 국내 질병부담을 파악하는데 기초자료를 제공하고자 하였다. 방법: 일개 제빵회사의 생산관련 근로자 596명에서 수습기간(3개월) 중이거나 참여를 거부한 216명을 제외하고,380명을 연구대상으로 하였다. 밀가루분진 노출형태에 따라 직접노출군과 간접노출군으로 직무 카테고리를 분류하고,설문조사는 ISAAC 설문항목에 직업력 등을 추가한 설문지를 사용하였다. 설문조사에서 천식이나 알레르기병과 관련된 증상이나 병력이 전혀 없는 간접노출군은 임상검사대상에서 제외하였다. 임상검사대상 233명에게 피부단자검사,혈청 특이 IgE 항체검사,산업의학 전문의와의 면담을 시행하였고,면담에서 천식이나 알레르기비염과 관련된 증상이나 병력이 확인된 31명을 연속적 PEFR 측정대상으로 하였다. PEFR 변동률로써 메타콜린 기관지유발검사대상을 선정하였고,메타콜린 기관 지유발검사에서 기관지과민성이 확인된 경우에 특이 기관지유발검사를 시행하였다. 제빵공 천식은 특이 기관지유 발검사에서 천식반응이 확인된 경우로 정의하였다. 결과: 연구대상의 밀가루 민감화율은 21.0%(직접노출군 25.9%,간접노출군 13.3%), 제빵공 천식 유병률은 3.2%(직접노출군 5.1%,간접노출군 1.8%)였다. 직접 노출군이 간접노출군에 비해 밀가루에 민감화될 위험이 높았으며(OR 2.15,95% CI=1.03∼4.51), 제빵공 천식에 이환될 위험은 통계적으로 유의하지 않았다(PR 2.52,95% CI=O.78∼8.18). 밀가루에 민감화된 군이 그렇지 않은 군에 비해 제빵공 천식에 이환될 위험이 매우 높았다(PR 38.63, 95% CI=6.14∼243.22). 결론: 이번 연구결과는 직업적으로 밀가루에 노출되는 국내 근로자에서 제빵공 천식이 적지 않을 것임을 시사하고 있다. 향후 제빵공 천식으로 인한 질병부담을 보다 정확히 파악하기 위해서는 국내에서 연구된 바 없는 밀가루 취급 사업장(제분회사 등)에 대한 연구가 필요하며,근로자의 건강과 사회경제적 위치를 보호하기 위한 체계적인 연구도 요구된다. Objectives: To determine the prevalence of baker's asthma due to flour dust in an industrial bakery in Korea. Methods: Of the 596 active workers, 380 were allocated to a category of either direct exposure (DE) or indirect exposure (IE) to flour dust and completed a modified ISAAC questionnaire. Of the 380 participants, 233 were screened by an occupational physician interview, a skin prick test, and an ELISA for serum-specific IgE antibodies to wheat flour extracts. Selected workers received serial monitoring of peak expiratory flow rate (PEFR), and positive PEFR respondents received a methacholine challenge test. The diagnosis of baker's asthma was confirmed by a specific inhalation challenge with wheat flour extracts. Results: The prevalence of sensitization to wheat flour and baker's asthma was 21.0% (25.9% DE, 13.3% IE) and 3.2% (5.1 % DE, 1.8% IE), respectively. DE had an increased risk of sensitization to wheat flour (OR 2.15, 95% CI = 1.03∼4.51). Sensitization to wheat flour and the prevalence of baker's asthma correlated significantly (PR 38.63, 95% CI = 6.14∼243.22). Conclusions: These findings indicate a considerable prevalence of baker's asthma among flour-exposed workers in Korea. Future studies will be required to survey the situation in flour mill companies and seek ways to protect the health and socioeconomic position of flour industry workers.

금속 촉매를 이용한 poly-Si의 결정화에 관한 연구

金善浩,李秀京,金泰延,康娜榮,金亨駿 弘益大學校 科學技術硏究所 2005 科學技術硏究論文集 Vol.16 No.-

Nickel induced crystallization of amorphous silicon (a-Si) has been studied by selective deposition of Ni on a-Si thin films. The kinetics of crystallization for MIC was found to be greatly enhanced than that of SPC. Ni-induced crystallization is a promising technique for low-temperature fabrication of poly-Si thin-film transistors needed for large area applications. Lateral growth of polycrystalline silicon mediated by the formation of nickel silicide, has been successfully employed for the fabrication of high-performance TFTs. A-Si thin films on which Ni films were deposited with various thickness were crystallized as a function of annealing temperatures. Throughout the thesis work, wise choice of both the thickness of Ni and the annealing temperature was found to produce poly-Si films with high quality, thus potentially resulting in the production of TFTs with high performance.

비심장 수술 환자에서 수술 전후 심장사건의 위험도 평가를 위한 심근관류 SPECT 의 유용성

이명철,임석태,이동수,강원준,정준기 대한핵의학회 1999 핵의학 분자영상 Vol.33 No.3

Purpose: We investigated whether myocardial SPECT had additional usefulness to clinical, functional or surgical indices for the preoperative evaluation of cardiac risks in noncardiac surgery. Materials and Methods: 118 patients (M: F=66:52, 62.7±10.5 years) were studied retrospectively. Eighteen underwent vascular surgeries and 100 nonvascular surgeries. Rest T1-201/stress Tc-99m-MIBI SPECT was performed before operation and cardiac events (hard event: cardiac death and myocardial infarction; soft event: ischemic ECG change, congestive heart failure and unstable angina) were surveyed through perioperative periods (14.6±5.6 days). Clinical risk indices, functional capacity, surgery procedures and SPECT findings were tested for their predictive values of perioperative cardiac events. Results: Peri-operative cardiac events occurred in 25 patients (3 hard events and 22 soft events). Clinical risk indices, surgical procedure risks and SPECT findings but functional capacity were predictive of cardiac events. Reveible perfusion decrease was a better predictor than persistent decrease. Multivariate analysis sorted` out surgical procedure risk (p=0.0018) and SPECT findings (p=0.0001) as significant risk factors. SPECT could re-stratify perioperative cardiac risks in patients ranked with surgical procedures. Conclusion: We conclude that myocardial SPECT provides additional predictive value to surgical type risks as well as clinical indexes or functional capacity for the prediction of preoperative cardiac events in noncardiac surgery.

Thickness-dependent thermal resistance of a transparent glass heater with a single-walled carbon nanotube coating

Kang, Tae June,Kim, Taewoo,Seo, Sung Min,Park, Young June,Kim, Yong Hyup Elsevier 2011 Carbon Vol.49 No.4

<P><B>Abstract</B></P><P>A single-walled carbon nanotube (SWCNT) film was formed on a glass substrate by using the dip-coating method and the resulting material used as a transparent glass heater. The heaters have an optical transparency above 95% in visible light. Their performance was investigated by measuring their heating/cooling characteristics and thermal resistance. They have a heating performance that is ∼70% higher than that of Pt film heaters, which are widely used. The thickness dependence of the thermal resistance is observed, and can be understood in relation to heat-transfer losses that are related to the porous structure of the SWCNT film. The stability and reliability of the heater were also investigated.</P>

Electromechanical properties of CNT-coated cotton yarn for electronic textile applications

Kang, Tae June,Choi, Ajeong,Kim, Dai-Hong,Jin, Kyoungcheol,Seo, Dong Kyun,Jeong, Dae Hong,Hong, Seong-Hyeon,Park, Yung Woo,Kim, Yong Hyup Institute of Physics Publishing 2011 Smart materials & structures Vol.20 No.1

<P>Smart fabrics have attracted considerable attention due to their potential applications. The essential features of smart fabrics include wearability, weaveability, and stretchability, as well as their sensing/response capability, which is frequently based on electrical measurement. Thus, the electromechanical behavior of these fabrics is considered the most important material property. Here, we report the negative piezoresistance of single-walled carbon nanotube coated cotton yarn (SWNT-CY). The gauge factor (the ratio of the normalized change in piezoresistance to the change in strain) of SWNT-CY is measured to be − 24. It is noteworthy that the factor is negative and an order of magnitude higher than that for conventional metal strain gauges. The negative piezoresistance is due to mechanical contact between fabric fibers, which leads to better electrical paths of SWNT networks. The conduction behavior can be modeled as fluctuation-induced tunneling (FIT) through the contact barriers between conducting regions. The effective barrier strength of strained SWNT-CY is measured to be ∼ 30% lower than that of unstrained SWNT-CY. This characteristic may offer new design opportunities for wearable electronics and has significant implications for sensor applications. </P>

Modification of Optical and Mechanical Surface Properties of Sputter-Deposited Aluminum Thin Films through Ion Implantation

Kang, Tae June,Kim, Jeong-Gil,Lee, Ho-Young,Lee, Jae-Sang,Lee, Jae-Hyung,Hahn, Jun-Hee,Kim, Yong Hyup 한국정밀공학회 2014 International Journal of Precision Engineering and Vol.15 No.5

Aluminum (Al) thin films are used widely as an electronic material in a variety of applications because of their high conductivity, optical reflectance and low cost. In the present study, helium (He) and nitrogen (N2) ions were implanted in sputter-deposited Al thin films with different doses and energies, and the changes in the film properties, such as the surface roughness, optical reflectance, hardness and Young's modulus, were investigated. The results showed that the implantation of both ions smooth the surface of Al thin films by decreasing the hillock density, resulting in low global surface roughness. In particular, in the case of He ion implantation, the moderated degradation of optical reflectance was observed compared to the film implanted with nitrogen ion. On the other hand, excessive ion implantation increased the local (short-range) surface roughness, which deteriorated the optical reflectance of the Al films. The continuous stiffness measurement technique in nano-indentation showed that ion implantation increased the hardness near the surface. He ion implantation hardened the surface of the Al thin film, and almost 2 times higher surface hardness was achieved with an ion dose of $10^{18}ions/cm^2$ at 40 KeV.

Ionic Seebeck effect based waste thermal energy harvesting

Tae June Kang(강태준) 대한기계학회 2019 대한기계학회 춘추학술대회 Vol.2019 No.11