• Journal of Ocean Engineering and Technology
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• v.29 no.4
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• pp.322-330
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• 2015

As a new technical approach, a hydraulic and magnetic clamp device was developed to realize a magnetic clamp crane system by simultaneously actuating eight individual hydraulic cylinders. In this approach, an Sr-type of ferritic permanent magnet (SrO· 6Fe₂O₃), rather than the previous electromagnet, was utilized for the purpose of lifting and transporting the large curved steel plates used for manufacturing ships. This study had the goal of developing and manufacturing a hydraulic, magnetic clamp prototype composed of three main parts, including the base frame, cylinder joint, and magnet joint, in order to safely transport curved steel plates. Furthermore, this research included a performance evaluation of the manufactured prototype and acquired the purposed quantity value in the performance test. The most significant item, the magnetic adhesive force (G), was evaluated in a performance test, which utilized a ferritic permanent magnet (Sr type) with 3700~4000 G of residual induction (Br) and 2640/2770 Oe of coercive force (Hc). In particular, relevant items such as the hoist tension (kN), transportation time (s), and applied load (Kgf) on the hydraulic cylinders were also evaluated in order to determine the optimum values.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1295-1296
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• 2008

Hydrogen peroxide ($H_2O_2$) biosensor is one of the most developing sensors because this kind of sensors is highly selective and responds quickly to the specific substrate. Hemoglobin (Hb) has been used as ideal biomolecules to construct hydrogen peroxide biosensors because of their high selectivity to $H_2O_2$. The direct electron transfer of Hb has widely investigated for application in the determination of $H_2O_2$ because of its simplicity, high selectivity and intrinsic sensitivity. An electrochemical detection for hydrogen peroxide was investigated based on immobilization of hemoglobin on DNA/Fe(pyterpy)$^{2+}$ modified gold electrode. The pyterpy monolayers were firstly an electron deposition onto the gold electrode surface of the quartz crystal microbalance (QCM). It is offered a template to attach negatively charged DNA. The fabrication process of the electrode was verified by quartz crystal analyzer (QCA). The experimental parameters such as pH, applied potential and amperometric response were evaluated and optimized. Under the optimized conditions, this sensor shows the linear response within the range between $3.0{\times}10^{-6}$ to $9.0{|times}10^{-4}$ M concentrations of $H_2O_2$. The detection limit was determined to be $9{\times}10^{-7}$ M (based on the S/N=3).

• Particle and aerosol research
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• v.8 no.2
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• pp.89-95
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• 2012

Spherical mesoporous silica particles, of which main pore diameter was 3.8 nm, were successfully prepared by spray pyrolysis from aqueous silicic acid. The effect of precursor concentration, reaction temperature, and the addition of urea and PEG on the particle diameter and pore properties such as pore diameter, total pore volume, and specific surface area were investigated by using FE-SEM, particle size analyzer, and nitrogen absorption-desorption analysis. With an increase of the precursor concentration from 0.2 M to 0.7 M, the average particle diameter, total pore volume, and specific surface area of the porous silica particles increased from 0.56 to $0.96\;{\mu}m$, 0.434 to $0.486\;cm^3/g$, 467.8 to $610.4\;m^2/g$, respectively. Within the temperature range $(600\;^{\circ}C{\sim}800\;^{\circ}C)$, there was no significant difference in the pore diameter, total pore volume, and specific surface area. In addition, the addition of urea as an expansion aid led to slight increases in particle diameter, pore diameter, and specific surface area. However, when the polyethylene glycol (PEG) as an organic template was used, the total pore volume of porous particles increased dramatically.

• BMB Reports
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• v.41 no.2
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• pp.164-169
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• 2008

The tumor suppressor gene p53 regulates apoptotic cell death and the cell cycle. In this study, we investigated the role of p53 in nitric oxide (NO)-induced apoptosis in vascular smooth muscle cells (VSMCs). We found that the NO donor S-nitroso-N-acetyl-penicillamine (SNAP) increased apoptotic cell death in p53-deficient VSMCs compared with wild-type cells. The heme oxygen-ase (HO) inhibitor tin protoporphyrin IX reduced the resistance of wild-type VSMCs to SNAP-induced cell death. SNAP promoted HO-1 expression in both cell types. HO-2 protein was increased only in wild-type VSMCs following SNAP treatment; however, similar levels of HO-2 mRNA were detected in both cell types. SNAP significantly increased the levels of non-heme-iron and dinitrosyl iron-sulfur clusters in wild-type VSMCs compared with p53-deficient VSMCs. Moreover, pretreatment with FeSO4 and the carbon monoxide donor CORM-2, but not biliverdin, significantly protected p53-deficient cells from SNAP-induced cell death compared with normal cells. These results suggest that wild-type VSMCs are more resistant to NO-mediated apoptosis than p53-deficient VSMCs through p53-dependent up-regulation of HO-2.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.12
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• pp.1940-1947
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• 2020

Objective: Combination of two stressors on alteration of mineral footprints in animals needs due attention to meet maximum production and welfare, particularly in grazing sheep. This study tested whether ewes (Ovis aries) exposed to water deprivation and thermal-humidity stressors had altered mineral footprints in their wool, serum, urine, and feces. Methods: Nine ewes (age = 3 years; mean body weight = 41±3.5 kg) were divided among a control group with free access to water, and treatment groups with water deprivation lasting either 2 h (2hWD) or 3 h (3hWD) after feeding. Using a 3×3 Latin square design, animals were assigned to treatment groups for three sampling periods of 21 days each (n = 9). Blood was collected by jugular venipuncture. Wool was collected at the end of periods 2 and 3. Metabolic crates designed with metal grated floors were used for urine and feces collection. We measured sodium (Na), magnesium (Mg), phosphorus (P), chloride (Cl), calcium (Ca), manganese (Mn), copper (Cu), iron (Fe), and zinc (Zn). Results: The wool mineral levels did not differ between the treatment groups, although K was marginally lower (p = 0.10) in the 2hWD group. The serum and urine mineral levels did not differ between the treatments (p>0.05). Fecal K was significantly lower in the 2hWD group than in the other groups (p≤0.05). Conclusion: In conclusion, water deprivation and thermal-humidity exposure altered the excretion of K, but not of other minerals, in the wool, urine, feces, or serum of ewes. Thus, no additional mineral supplementation is needed for water deprived ewes during thermalhumidity exposure.

• Journal of Bio-Environment Control
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• v.7 no.1
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• pp.35-41
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• 1998

This experiment was conducted to find out the effect of artificial light sources(high-pressure sodium lamp, metal halide lamp and fluorescent lamp) on growth of crisphead lettuce(Lactuca sativa L.) in a plant factory. No significant differences in leaf fresh and dry weight were presented among them. Lettuce plants grown under fluorescent lamp showed the lowest growth. Considering the growth of lettuce and efficiency of lamps, it is worth using HPS(high-pressure sodium) lamp in plant factories. The leaves of lettuce plants grown under artificial light sources showed tipburn symptoms at 14th day after transplanting. The beginning of tipburn symptom have been seen on the ninth to tenth leaves from the cotyledons. It is estimated that the occurrence of tipburn was related to rapid growth and K uptake of the lettuce Plants. The Ca, Mg. Cu and Zn elements tended to be accumulated in the nutrient solutions but the T-N, P, Fe and Mn elements keep in balance in them.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.429.2-429.2
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• 2014

ZnO nanowire is known as synthesizable and good mechanical properties. And, stimuli-responsive polymer is widely used in the application of tunable sensing device. So, we combined these characteristics to make precise tunable sensing devise. In this work, we investigate the dependence of ZnO nanowire alignment and morphology on si substrate using nanosphere template with various conditions via hydrothermal process. Also, pH-temperature dependant tuning ability of nanostructure was studied. The brief experimental scheme is as follow. First, Zno seed layer was coated on a si wafer ($20{\times}20mm$) by spin coater. And then $1.15{\mu}m$ sized close-packed PS nanospheres were formed on a cleaned si substrate by using gas-liquid-solid interfacial self-assembly method. After that, zinc oxide nanowires were synthesized using hydrothermal method. Before the wire growth, to specify the growth site, heat treatment was performed. Finally, NIPAM(N-Isopropylacrylamide) was coated onto as-fabricated nanostructure and irradiated by UV light to form the PNIPAM network. The morphology, structures and optical properties are investigated by FE-SEM(Field Emission Scanning electron Microscopy), XRD(X-ray diffraction), OM(Optical microscopy), and WCA(water contact angle).

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.434.2-434.2
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• 2014

We observe enhanced pH response of solution-gated field-effect transistors (SG-FET) having 1D-2D hybrid channel of vertical grown ZnO nanorods grown on CVD graphene (Gr). In recent years, SG-FET based on Gr has received a lot of attention for biochemical sensing applications, because Gr has outstanding properties such as high sensitivity, low detection limit, label-free electrical detection, and so on. However, low-defect CVD Gr has hardly pH responsive due to lack of hydroxyl group on Gr surface. On the other hand, ZnO, consists of stable wurtzite structure, has attracted much interest due to its unique properties and wide range of applications in optoelectronics, biosensors, medical sciences, etc. Especially, ZnO were easily grown as vertical nanorods by hydrothermal method and ZnO nanostructures have higher sensitivity to environments than planar structures due to plentiful hydroxyl group on their surface. We prepared for ZnO nanorods vertically grown on CVD Gr (ZnO nanorods/Gr hybrid channel) and to fabricate SG-FET subsequently. We have analyzed hybrid channel FETs showing transfer characteristics similar to that of pristine Gr FETs and charge neutrality point (CNP) shifts along proton concentration in solution, which can determine pH level of solution. Hybrid channel SG-FET sensors led to increase in pH sensitivity up to 500%, compared to pristine Gr SG-FET sensors. We confirmed plentiful hydroxyl groups on ZnO nanorod surface interact with protons in solution, which causes shifts of CNP. The morphology and electrical characteristics of hybrid channel SG-FET were characterized by FE-SEM and semiconductor parameter analyzer, respectively. Sensitivity and sensing mechanism of ZnO nanorods/Gr hybrid channel FET will be discussed in detail.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.457-457
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• 2014

오존발생방법은 다양한 방식으로 구현이 가능하나 대용량 장치를 만들기 위해서는 DBD (Dielectric barrier discharge) 구조의 형태의 가지고 있다. 이러한, DBD는 반도체의 MOS (Metal On Semiconductor)의 반대 구조를 가진 SOM (Semiconductor On Metal)의 형태를 가지고 있으며 대부분이 Oxidation 산화물을 가지고 구현한다. 오존발생기는 반도체 공정, 환경 및 정화 등 다양한 분야에 사용이 되고 있는 상황으로 성능개선을 위한 연구가 필요한 상황이다. 대표적으로 사용되는 물질인 $SiO_2$를 가지고 있는 상황이며 Silicon은 에너지 Bandgap이 1.1 eV로 금속위에 증착되어 통상적으로 사용되는 문턱전압은 0.7 V에 해당이 된다. 현재 점차적으로 연구가 진행되고 있는 $Al_2O_3$는 8.8 eV의 bandgap을 가지고 있으며 유전 상수가 9로 $SiO_2$인 3.9보다 높은 유전률 특징을 가지고 있다. 따라서, 본 연구는 오존 발생장치에 사용되는 방전관을 기존의 $SiO_2$에서 $Al_2O_3$ 방식으로 대체하므로써 실제적인 유전율의 값의 차이와 오존 발생시 오존변화율 증대에 관하여 연구하였다. $SiO_2$ 방전관은 Fe 메탈위에 약 3 mm정도의 두께를 binding시켜 N4L사의 PSM1700 모델 LCR meter를 사용하여 1.3 kHz시 7.2 pF의 유전율 확인 할 수 있으며 동일한 조건의 금속 메탈위에 $Al_2O_3$를 binding 시켜 측정한 결과 1.07 kHz시 10.7 pF의 유전율을 가지게 되어 40% 이상 높은 유전율을 가지게 되는 것을 확인 할 수 있다. 오존발생을 위하여 가변 주파수형 트랜스 드라이버를 통한 공진 주파수를 생성하여 방전 증폭을 위한 Amplifier를 통하여 변환률을 높이는 방식을 적용하여 MIDAC사의 I1801모델 적외선 분광기(FT-IR)를 통한 오존발생량을 측정하여 기존의 $SiO_2$의 방전관은 시간당 54 g의 오존 발생률 가지게 된다. $Al_2O_3$는 시간당 70 g 정도의 오존 발생률 가지므로 기존의 $SiO_2$ 보다 발생률 높은 것을 확인 할 수 있다.

• Journal of the Mineralogical Society of Korea
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• v.25 no.4
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• pp.313-322
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• 2012

몽골 우기누르 지역 철-망간 광상과 타미르골 지역 철 광상의 광체는 먼곤체지 층 내에 렌즈상으로 협재되는 특성을 갖는다. 이러한 광상은 캠브리아 기에서 실루리아기에 이르는 화산 기원의 퇴적형 광상인 타미르골-요루골 광상구에 해당된다. 우기누르 지역의 철-망간 광체와 타미르골 지역의 철광체는 주로 규암과 편암을 모암으로 하여 먼곤체지 층 내에 렌즈상으로 협재되어 있다. 우기누르지역의 편암이 주로 세리사이트 편암인 데 비해 타미르골 지역은 주로 백운모 편암이 나타나는 차이를 갖는다. 또한 우기누르 지역의 광석은 망간이10에서 12% 함유되나 타미르골 지역의 광석은 망간이 1% 이하로 함량이 낮은 특성을 갖는다. 우기누르 철 망간 광상의 철 광물은 주로 자철석, 적철석이 우세하게 나타나고 기타 철 산화물과 황철석이 미량으로 수반되어 나타나며, 망간 광물은 주로스페사틴, 버네사이트가 우세하게 나타나고 기타망간 산화물이 수반되어 나타난다. 타미르골 지역의 철 광석은 자철석이 우세하게 나타나고 적철석이 수반되며 황철석, 철 산화물, 탄산질 철 등이 미량으로 수반되어 나타난다. 우기누르 철-망간 광상에 대한 육상 자력탐사 결과 높은 자기 이상값을보이는 영역이 지표에서 확인된 광체의 방향과 같은 약 $N30^{\circ}W$ 방향으로 나타나며 지표에서 확인된 광체 이외에 지표에 드러나지 않은 부분에서도 연장되는 것이 확인되었다.