• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.274-274
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• 2014

금속칼코게나이드 화합물중 하나인 $MoS_2$는 초저 마찰계수의 금속성 윤활제로 널리 사용되고 있으며 흑연과 비슷한 판상 구조를 지니고 있어 기계적 박리법을 통한 그래핀의 발견 이후 2차원 박막 합성법에 대한 활발한 연구가 진행되고 있다. 최근 다양한 응용이 진행 중인 그래핀의 경우 높은 전자이동도, 기계적 강도, 유연성, 열전도도 등 뛰어난 물리적 특성을 지니고 있으나 zero-bandgap으로 인한 낮은 on/off ratio는 thin film transistor (TFT), 논리회로(logic circuit) 등 반도체 소자 응용에 한계가 있다. 하지만 $MoS_2$는 벌크상태에서 약 1.2 eV의 indirect band-gap을 지닌 반면 단일층의 경우 1.8 eV의 direct-bandgap을 나타내고 있다. 또한 단일층 $MoS_2$를 이용하여 $HfO_2/MoS_2/SiO_2$ 구조의 트랜지스터를 제작하였을 때 $200cm^2/v^{-1}s^{-1}$의 높은 mobility와 $10^8$ 이상의 on/off ratio 나타낸다는 연구가 보고되어 있어 박막형 트랜지스터 응용을 위한 신소재로 주목을 받고 있다. 한편 2차원 $MoS_2$ 박막을 합성하기 위한 대표적인 방법인 기계적 박리법의 경우 고품질의 단일층 $MoS_2$ 성장이 가능하지만 대면적 합성에 한계를 지니고 있으며 화학기상증착법(CVD)의 경우 공정 gas의 분해를 위한 높은 온도가 요구되므로 박막형 투명 트랜지스터 응용을 위한 플라스틱 기판으로의 in-situ 성장이 어렵기 때문에 이를 보완할 수 있는 $MoS_2$ 박막 합성 공정 개발이 필요하다. 특히 Plasma enhanced chemical vapor deposition (PECVD) 방법은 공정 gas가 전기적 에너지로 분해되어 chamber 내부에서 cold-plasma 형태로 존 재하기 때문에 박막의 저온성장 및 대면적 합성이 가능하며 고진공을 바탕으로 합성 중 발생하는 오염 요소를 효과적으로 제어할 수 있다. 본 연구에서는PECVD를 이용하여 plasma power, 공정압력, 공정 gas의 유량 등 다양한 공정 변수를 조절함으로써 저온, 저압 조건하에서의 $MoS_2$ 박막 성장 가능성을 확인하였으며 전구체로는 Mo 금속과 $H_2S$ gas를 사용하였다. 또한 향후 flexible 소자 응용을 위한 플라스틱 기판의 녹는점을 고려하여 공정 온도는 $300^{\circ}C$ 이하로 설정하였으며 합성된 $MoS_2$ 박막의 두께 및 화학적 구성은 Raman spectroscopy를 이용하여 확인 하였다. 공정온도 $200^{\circ}C$와 $150^{\circ}C$에서 성장한 $MoS_2$ 박막의 Raman peak의 경우 상대적으로 낮은 공정온도로 인하여 Mo와 H2S의 화학적 결합이 감소된 것을 관찰할 수 있었고 $300^{\circ}C$의 경우 약 $26{\sim}27cm^{-1}$의 Raman peak 간격을 통해 5~6층의 $MoS_2$ 박막이 형성 된 것을 확인할 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.11
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• pp.1579-1584
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• 2002

Twelve adult male crossbred (Sahiwal${\times}$Holstein Friesian) cattle were distributed into four groups of three each on body weight basis. Animals were given wheat straw as a basal diet. The animals of group I and II were supplemented with concentrate mixture and animals of group III and IV were supplemented with cold processed urea molasses mineral block (UMMB). Thirty mg monensin/day/animal was supplemented to the animals of group II and 35 ppm monensin were incorporated in the UMMB supplemented to the animals of group IV. Vit.A and D mixture was given to all the animals once a week. Dry matter (DM) intake (kg/d) through wheat straw was 19.0 percent higher in the UMMB (without monensin) supplemented group (group III) than those of the concentrate mixture (without monensin) supplemented group i.e. group I. Total DM intake (kg/d) was lower in the monensin supplemented groups than those of non-supplemented groups though differences were not statistically significant. Digestible dry matter, organic matter (OM), crude protein (CP) and total digestible nutrients (TDN) intake were similar in all the groups. Average block consumption for 45 d period in the group III (0.95 kg/d) and group IV (0.84 kg/d) did not differ significantly. DM digestibility (%) was significantly (p<0.01) higher in the group II (58.9) as compared to the group I (52.7) and group III (54.0) but similar to the group IV (57.2). OM digestibility was also significantly (p<0.05) higher in the group II (63.2) as compared to that of the group I (54.9) but similar to the group III (57.8) and IV (59.2). Ether extract (EE) digestibility was significantly (p<0.01) higher in the group I (76.9) and II (80.3) as compared to the group III (59.87) and IV (55.77). Nitrogen free extract (NFE) digestibility was significantly (p<0.05) higher in the group II (62.38) as compared to that of the other groups. Crude protein (CP) and crude fibre (CF) digestibilities were not affected either due to UMMB or monensin. Nitrogen balance did also not differ significantly among the groups. However, Ca and P balance (g/d) in the group III (3.1, 1.3) and IV (3.0, 1.4) were significantly (p<0.01) higher than those of the group I (0.6, 0.2) and II (0.4, 0.3). Blood glucose (mg/100ml) was significantly (p<0.01) higher in the group II (65.2) and IV (65.2) as compared to the group I (55.2) and group III (53.9). Plasma urea-N level (mg/100 ml) in the group III (19.0) and IV (17.8) were significantly (p<0.01) higher than that of the group I (10.5) and II (12.3). So, monensin supplementation either with cold process UMMB or concentrate mixture did not show any additional effect on feed intake and digestibility but increases blood glucose level in adult cattle.

• Journal of Chest Surgery
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• v.13 no.3
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• pp.174-185
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• 1980

It was my great nohour that I can be exposed to such plenty materials of the coronary bypass surgery. Here, I am summarizing the xoronary bypass surgery, clinically. The material is serial 101 patients who underwent coronary bypass surgery between July 17, 1979 to November 30, 1979 in Shadyside Hospital, University of Pittsburgh. 1. Incidence of the Atherosclerosis is frequent in white, male, fiftieth who are living in industrialized country. It has been told the etiologic factor of the atherosclerosis is hereditary, hyperlipidemia, hypertension, smoking, drinking, diabetes, obesity, stress, etc. 2. The main and most frequent complication of the coronary atherosclerosis is angina pectoris. Angina pectoris is the chief cause of coronary bypass surgery and the other causes of coronary bypass surgery are obstruction of the left main coronary artery, unstable angina, papillary muscle disruption or malfunction and ventricular aneurysm complicated by coronary artery disease. 3. The preoperative clinical laboratory examination shows abnormal elevation of plasma lipid in 82 patint, plasma glucose in 40 patient, total CPK-MB in 24 patient stotal LDH in 22 patient out of 101 patient. 4. Abnormal ECG findings in preoperative examine were 29.1% myocardial infarction, 25.8% ischemia and injury, 14.6T conduction defect. 5. Also we had done Echocardiography, Tread Mill Test, Myocardial Scanning, Vectorcardiography and Lung function test to get adjunctive benefit in prediction of prognosis and accurate diagnosis. 6. The frequency of coronary atherosclerosis in main coronary arteries were LAD, RCA and Circumflex in that order. 7. The patients' main complaints which were became as etiologic factor undergoing coronary bypass surgery were angina, dyspnea, diaphoresis, dizziness, nausea and etc. 8. For the coronary bypass surgery, we used cardiopulmonary bypass machine, non-blood, diluting prime, cold cardioplegic solution and moderate cooling for the myocardial protection. 9. We got the grafted veins from Saphenous and Cephalic vein. Reversed and anastomosed between aorta and distal coronary A. using 5-0 and 7-0 prolene continuous suture. Occasionally we used internal mammary A. as an arterial blood source and anastomosed to the distal coronary A. and to side fashion. 10. The average cardiopulmonary bypass time for every graft was 43.9 min. and aortic clamp time was 23 minute. We could Rt. coronary A. bypass surgery only by stand by the cardiopulmonary machine and in the state of pumping heart. 11. Rates by the noumbers of graft were as follow : 21.8% single, 33.7% double, 26.7% triple, 13.9% quadruple, 3% quintuple and 1% was sixtuple graft. 12. combined procedures with coronary bypass surgery were 6% aneurysmectomy, 3% AVR, 1% MVR, 13% pacer implantation and 1% intraaortic ballon setting. 13. We could see the complete abolition of anginal pain after operation in 68% of patient, improvement 25.8%, no change in 3.1%, and there was unknown in 3%. 14. There were 4% immediate postoperative deaths, 13.5% some kinds of heart complication, 51.3% lung complications 33.3% pleural complications as prognosis.

• Journal of Chest Surgery
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• v.29 no.8
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• pp.850-860
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• 1996

Oxygen free radicals and their metabolites have been implicated as possible causes of reperrusion injury In animal models. Their role in the clinical setting is still controversial. The aim of this study was to evaluate the degree of tissue damage, oxidative stress. and changes in the antioxidant enzyme system in patients undergoing cor nary artery bypass graft operations(CABG) with myocardial protection by cold blood cardioplegia. In patients undergoing CABG(n:10). the levels of lactate dehydrogenate(LDH), creatine phosphokinase MB fraction(CK-MB), and malondialdehyde(M DA) were measured In the coronary sinus effluent before aortic cross clamping and 20 minutes after reperfusion. At the same time, the myocardial tissue activities of superoxide dismutase(SOD). catalase(CAT), glutathione peroxiddse(GSHPX), glutathione reductase (GSSGRd), and glucose 6-phosphate dehydrogenate(GfPDH ) were determined in the right atrial auricle excised before aortic cross clamping and in the left atrial auricle excised 20 minutes after reperfuslon. The levels of increased significantly after reperrusion(p< U.05). There were no significant changes in CAT and CfPDH levels. Western blot analysis was performed to study the induction of antioxidant enzyme and demonstrated increased amount of Cu,Zn-SOD.

• Journal of Aquaculture
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• v.19 no.1
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• pp.47-51
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• 2006

Experiments were performed to find out the physico-chemical properties of milt and sperm motility in various storage conditions using starry flounder (Platichthys stellatus). The average sperm concentration and spermatocrit in stripped milt were $6.00{\pm}0.98{\times}10^8/mL\;and\;72{\pm}5$, respectively. The osmolality and pH were $337{\pm}9mmol/kg$ and $7.7{\pm}0.1$, respectively. The sperm of starry flounder was preserved with artificial seminal plasma (ASP), Stein's solution (SS) and marine fish Ringer's solution (MFRS) at $0^{\circ}C,\;2^{\circ}C,\;and\;4^{\circ}C$. The most effective condition for cold storage was SS at $0^{\circ}C$, and the preserved sperm remained motile for 30 days.

• Journal of Food Hygiene and Safety
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• v.35 no.1
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• pp.60-67
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• 2020

This study determined the microbial contamination levels of hot pepper at harvest, sorting, and distribution stages to suggest a way of reducing the microbial contamination of hot peppers by changing work gloves used throughout these processes. According to the monitoring results, the contamination levels of total aerobic bacteria (TAB) were found in the following order: soil (5.3±0.9 log CFU/g), hot pepper (4.2±0.9 log CFU/g), gloves (4.2±0.6 log CFU/g), baskets (4.1±0.7 log CFU/ g), clippers (3.9±0.6 log CFU/ g) and water (3.2±1.1 log CFU/g) at harvest stage. The contamination level of coliforms were found in the following order: soil (2.2±0.9 log CFU/g), hot pepper (2.2±0.3 log CFU/g), gloves (2.1±0.6 log CFU/g), clippers (2.0±0.21 log CFU/ g) and baskets (1.9±1.1 log CFU/ g) at harvest stage. TAB on hot pepper at the harvest stage was reduced from 4.2±0.9 log CFU/g to cold storage 3.8±0.2 log CFU/g and room temperature storage 2.6±0.3 log CFU/g, respectively. By the replacement of work gloves and lower distribution temperature, TAB levels of the peppers were significantly reduced compared to those without replacement and distributed at room temperature. In addition, the utilization of plasma was effective on reducing microbial contamination of hot pepper. These results demonstrated that appropriate replacement of gloves at the harvest stages, using plasma in the distribution stage, and refrigerated distribution conditions, which are simple and easy to practice in the field, are effective to reduce microbial contamination on hot peppers.

• Food Science and Biotechnology
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• v.15 no.1
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• pp.63-69
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• 2006

The primary objective of this study is to determine whether a diet supplemented with brown rice koji (BRK) results in a reduced stress response in rats and mice. BRK, which has been suggested as a candidate for use as a stress- and fatigue-fighting supplement, was compared with red ginseng extract (RG) for its stress-reducing potential. The animals in this study were divided into no-stress, stress, RG, and BRK groups of 8 to 10 animals each. Stress was induced by means of immobilization (being restrained in plastic tubes for 30 min and electroshock (0.5 mA in mice or 2 mA in rats for 5 min). The no-stress group was not exposed to stress. Rats in the RG group received oral doses of 200 mg RG extract/kg body weight daily. The BRK group was fed a 30% BRK diet and exposed to stress. Animals were given supplements for 7 days before being exposed to stress, and then were given supplements for 5 days with exposure to stress. When the stress exposure ended, the animals were observed for stress-related changes in behavior and their plasma corticosterone levels were measured. BRK supplementation was associated with a partial blockade of the effects of stress on locomotion and elevated plus-maze test results in rats and mice. It was also associated with a partial reduction in stress-induced behaviors such as freezing, burrowing, smelling, face-washing, and rearing. BRK supplementation did not have a significant effect on plasma corticosterone levels, which were increased in the animals exposed to stress (p<0.01). The mice in the RG group received RG in water (2 mg RG/ mL $H_2O$), and the BRK group received a 30% BRK diet (weight) for 7 days. Both groups were evaluated for signs of fatigue. BRK supplementation increased endurance, as indicated by time on the rota-rod, in cold water, and on the horizontal wire. These results suggest that BRK supplementation partially protects the animal from the effects of stress and may also contribute to resistance to fatigue on physical exertion.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.3
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• pp.480-487
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• 1997

Vitellogenin (Vg) was purified from plasma of $estradiol-17\beta(E_2)-treated$ spotted flounder, verasper variegatus, by preripitation with cold distilled water, followed by fractionation using a Sepharose CL-6B column chromatography. $E_2-induced$ protein was identified as Vg by SDS-PAGE and western blot analysis. The molecular weight of the purified Vg was estimated 175 kD as determined by SDS-PAGE. In order to measure the Vg level, monoclonal antibodies against Vg were produced by hybridoma technique. Purified Vg was immunized into Balb/c mice and then the spleen cells from mice were fused with NS-1 myeloma cells. The hybridoma cells were screened by enzyme-linked immunosorbent assay (WLISA) and subcloned by limiting dilution. The hybridoma clones which secreted antibodies highly reactive to the purified Vg were designated as 4D6. Its specificity was demonstrated by western blot from plasma of untreated, $E_2-treated$ male fish, and purified Vg.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.2
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• pp.55-63
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• 2009

This study was performed to evaluate the heavy metal contents in various packaging board. Domestic and foreign OCC (old corrugated containers) and old duplex boards were used as raw materials. Tests were made for the printed and unprinted parts of the sample. Heavy metal contents of old food packaging boards made from virgin pulp fibers were also evaluated. The contents of heavy metals including lead (Pb), cadmium (Cd), barium (Ba), arsenic (As), antimony (Sb), selenium (Se), and mercury (Hg) were determined using ICP-AES (Inductively Coupled Plasma - Atomic Emission Spectrometer), and CV-AAS (Cold vapor-atomic absorption spectrometer) after digesting the samples in a microwave oven. The contents of heavy metals contained in domestic packaging board were higher than those in overseas samples, and OCC showed higher contents of heavy metals than old duplex boards. Printed parts gave greater heavy metal contents than unprinted parts. Results indicate that recycling of paper and paperboard products increases the heavy metal contamination of the paper packaging products and this derives mostly from the heavy metals contained in printing inks. Recycling processes that decrease heavy metals in recycled fibers and new printing inks that contains less heavy metals should be developed to solve the problem associated with the heavy metals in packaging paper products.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.1
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• pp.21-30
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• 2017

Of the marine engine components, the piston crown and exhaust valve are repaired most frequently. These works are conducted through conventional welding processes such as GTAW or SAW, domestically in marine engine repair factories. New high-efficiency welding or overlay processes such as tandem SAW, tandem MAG, hybrid TIG-MIG welding, pulsed-GMAW, CMT welding, and super TIG welding have been developed recently. Moreover, the plasma transfered arc (PTA) process is an efficient spray method for overlaying on the exhaust valve. In this review paper, the new high-efficiency repair welding methods are introduced for marine engine components. The problems due to repair welding for marine engine components are also presented.