• 한국태양에너지학회 논문집
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• 제34권6호
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• pp.49-56
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• 2014

Research about hybrid solar air-water heater that can make heated air and hot water was conducted as a part of improving efficiency of solar thermal energy. At this experiment, ability of making heating air and hot water was investigated and compared with traditional solar air heater and flat plate solar collector for hot water when air or liquid was heated respectively. Comparing hybrid solar air-water heater that used in this experiment to other solar air heater studied already, it has a lower efficiency at same mass flow rate. Air channel structure, fin's shape and arrangement in the air channel result in these difference then the ability of air heating need to be improved with changing these thing. In case of making hot water, performance was shown as similar with traditional system although the air channels were established beneath absorbing plate. But the heat loss coefficient was shown higher value by installing of air channel. Also the performance of hot water making was shown lower value at same liquid mass flow rate with traditional flat plate solar collector for hot water. So the necessity of performance improvement at lower mass flow rate of each heating medium can be confirmed.

• Journal of Plant Biotechnology
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• 제44권2호
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• pp.203-206
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• 2017

The soil organisms that develop beneficial Symbiotic relationships with plants roots and contribute to plant growth are mycorrhizal (AM) fungi. Arbuscular mycorrhizal inoculations change the growth and biochemical composition of the host plant and soil. Mycorrhizal root systems do augment the absorbing area of roots from 10 to 100 times thereby greatly improving the ability of the plants to utilize the soil resources. A pot experiment was conducted during the kharif seasons at Jaipur, Rajasthan, to find out the effects of three different indigenous AM fungi i.e. Glomus mosseae, Glomus fasciculatum and Gigaspora decipiens either single and in combination inoculation on biochemical and histochemical changes of Pearl millet (Pennisetum glaucum L.) grown under barren soil conditions. The AM fungus has shown to improve the tolerance of plant to drought stress. Experimental results showed that AM fungi treated plants improved their plants growths, biochemical and histochemical changes as compared to non-mycorrhizal treatments. The AM fungi inoculated plant was found to be attaining maximum plant biochemical and histochemical substances in Glomus mosseae (alone) and also Glomus mosseae + Glomus fasciculatum treatments.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 추계학술발표대회
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• pp.14-14
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• 2009

High frequency electromagnetic(EM) waves are increasingly being applied in industries because of saturationat lower frequency bands as a result of huge demand. However, electromagneticinterference (EMI) has become a serious problem, and as a result, highfrequency EM absorbers are now being extensively studied. Also, recentdevelopments in absorber technology have focused on producing absorbers thatare thin, flexible, and strong. Hence, one-dimension ferrous nano-materials area potential research field, because of their interesting electronic andmagnetic properties. Commercially, EM wave absorbing products are made ofcomposites, which blend the insulating polymer with magnetic fillers. Inparticular, the shape of the magnetic fillers, such flaky, acicular, or fibrousmagnetic metal particles, rather than spherical, is essential for synthesizingthin and lightweight EM wave absorbers with higher permeability. High aspectratio materials exhibit a higher permeability value and therefore betterabsorption of the EM wave, because of electromagnetic anisotropy. Nanowires areusually fabricated by drawing, template synthesis, phase separation, selfassembly, and electrospinning with a thermal treatment and reduction process.Producing nanowires by the electrospinning method involves a conventionalsol-gel process that is simple, unique, and cost-effective. In thispresentation, Magnetic nanowire and dielectric materials coated magneticnanowire with a high aspect ratio were successfully synthesized by theelectrospinning process with heat treatment and reduction. In addition toestimating the EM wave absorption ability of the synthesized magnetic anddielectric materials coated magnetic nanowire with a network analyzer, weinvestigated the possibility of using these nanowires as high-frequency EM waveabsorbers. Furthermore, a wide variety of topics will be discussed such as thetransparent conducting nanowire and semiconducting nanowire/tube with theelectrospinning process.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.794-798
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• 2003

천연추출물로서 미백 재료로 널리 쓰이고 있는 옥용산에 대해서 in vitro 미백활성을 UV 흡수능, tyrosinase 저해활성 그리고 free radical 소거활성을 측정함으로서 검정해 보았다. 옥용산 UV-B와 C 영역에 걸쳐서 높은 자외선 흡수능을 보이는 것으로 관찰이 되었으며 0.8 % 이상의 농도에서 80% 이상의 tyrosinase 저해활성을 가지는 것을 관찰하였다. 또한 조협, 승마, 감송, 정향, 찹쌀분과 옥용산의 추출물은 높은 free radical 소거능을 가지는 것으로 확인되었다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVI)
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• pp.541-543
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• 2005

조협은 trosinase 저해 활성 실험 결과 1.9%(w/v) 이상의 농도에서 70%이상의 저해를 나타내고, UV 흡수능에서는 220-230nm 에서 최대 흡수 파장이 나타나고 250-550nm 에서 고르게 흡수되는 경향을 보인다. 조협은 자외선 차단효과와 활성산소종 형성 억제 및 멜라닌 생성을 저해함으로써 피부미백 효과에 기여한다. 따라서 조협을 이용한 liposome을 제조하여 미백화장품에의 응용 가능성을 높여 줄 수 있다.

• 한국수소및신에너지학회논문집
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• 제2권1호
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• pp.15-21
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• 1990

Nickel-hydrogen battery systems with metal hydride alloys are expected to have both higher energy density and lower pollution than nickel-cadmium cells. Nickel-hydrogen storage cells are expected to be well-suited for use in space crafts for a large capacity power storage system. Their major advantages are not only a capability of deep DOD(depth of discharge) using but also with excellent durability under excessive overcharging and overdischarging. In this study, the charge/discharge capacities, anodic polarization characteristics and durability for the continious charge/diacharge cycling of the $Ti_{1-X}Zr_XVNi$ and $Ti_{1-X}Zr_XV_{0.5}Ni_{1.5}$ alloys were measured by electrochemical method. The electrode properties of the copper or nickel plated $Ti_{1-X}Zr_XV_{0.5}Ni_{1.5}$ alloys were examined with a battery charge/discharge testing system in the temperature range of -5 to $25^{\circ}C$.

• 한국포장학회지
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• 제12권1호
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• pp.35-40
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• 2006

Cushioning systems, which are cushion material and its designed configuration, are important to protect fragile items since they act as buffers between the impact force and the fragile product. As cushioning materials, several plastic foams are commonly used in industry. However, the utilization of the plastic material has been causing a solid waste problem and pollution. Thus, as an alternative cushion material to the plastic foams, a corrugated cushion, which is considered environmentally friendly and cheap material, was put into drop tests and its impact shock attenuation was investigated. Flat and free drop data were recorded and compared to the dynamic shock of EPS cushion. In addition, the mathematical model of the shock attenuation of the corrugated cushion was developed. The result showed that the corrugated cushion gave an excellent protection for items that were subjected to the limited number of drops. There was no significant difference of the shock absorbing ability between the EPS and corrugated cushions. Energy density model of cushioning material successfully explained the mechanical behavior and fatigue of the corrugated cushions.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.934-937
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• 2006

This investigation presents a topology formulation to design optimal poroelastic acoustic foams to maximize absorbing ability. For successful formulation, a single set of equations based on Biot's theory is adopted and an appropriate material interpolation strategy is newly developed. Because there was no earlier attempt to solve poroelastic acoustic foam design problems in topology optimization setting, many challenging issues including modeling and interpolation must be addressed. First, the simulation accuracy by a proposed unified model encompassing acoustic air and poroelastic material was checked against analytical and numerical results. Then a material interpolation scheme yielding a distinct acoustic air-poroelastic material distribution was developed. Using the proposed model and interpolation scheme, the topology optimization of a two-dimensional poroelastic acoustic foam for maximizing its absorption coefficient was carried out. Numerical results show that the absorption capacity of an optimized foam layout considerably increases in comparison with a nominal foam layout.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 1999년도 춘계종합학술대회
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• pp.432-436
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• 1999

최근 저자통신기술의 발달은 인간의 생활을 윤택하게 해주는 반면, 전자파 발생요인의 증가와 함께 심화되고 있는 전자파장해에 대한 대책이 사회적으로 큰 관심을 끌고 있다. 전자파 장해 및 내성 측정을 위한 전파암실용 전파흡수체가을 충분히 만족시키기 위해서는, 주파수 대역이 30 MHz～1,000 MHz에서 20 dB 이상의 전파흡수능이 요구되고 있으며, 앞으로 30 MHz에서 5,000 MHz 이상으로 주파수 대역이 확장될 전망이다. 본 논문에서는 위와 같은 요구조건을 만족하는 페라이트 기둥형 돌기부를 가지는 전파흡수체를 제안하고 이를 등가재료정수법에 의하여 광대역 설계하였다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2000년도 추계종합학술대회
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• pp.153-156
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• 2000

전자공학 및 전파 통신기술의 눈부신 발전은 우리의 생활을 풍요롭게 해주는 반면, 전파의 사용증가로 인한 EMC대책이 사회적으로 중요하게 부각되고 있다. EMI/EMC 측정을 위한 전파무향실이 국제기준을 만족하려면 이를 구성하는 전파흡수가 30 MHz - 1 GHz까지의 주파수 대역에서 20 dB 이상의 전파흡수능을 가져야 한다. 그러나, 1998년 11월 CISPR11은 주파수대역을 30 MH2 - 18 GHz까지 확장하였다. 본 논문에서는 위의 조건을 만족하는 원추절단형 전파흡수체를 제안하고 등가재료정수법으로 광대역 설계하였다. 나아가서, 전파흡수체를 제작하여 그 결과를 이론치와 비교, 분석하였다.