• Journal of the Korean Vacuum Society
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• v.20 no.2
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• pp.155-163
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• 2011

Carbon nanotubes (CNT) have been attracted much attention since they have been expected to be used in various areas by virtue of their outstanding physical, electrical, and chemical properties. In order to make full use of their prominent electric conductivity in some areas such as electron emission sources, device interconnects, and electrodes in energy storage devices, direct growth of CNT with vertical alignment is definitely beneficial issue because they can maintain mechanical stability and high conductivity at the interface between substrates. Here, we report direct growth of vertically aligned CNT (VCNT) on Cu foils using thermal chemical vapor deposition and characterize the field emission property of the VCNT. The VCNT's height was controlled by changing the growth temperature, growth time, and catalytic layer thickness. Optimum growth condition was found to be $800^{\circ}C$ for 20 min with acetylene and hydrogen mixtures on Fe catalytic layer of 1 nm thick. The diameter of VCNT grown was smaller than that of usual multi walled CNT. Based on the result of field emission characterization, we concluded that the VCNT on Cu foils can be useful in various potential applications where high conductivity through the interface between CNT and substrate is required.

• Journal of the Korean Vacuum Society
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• v.19 no.3
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• pp.224-229
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• 2010

Indium oxide $(In_2O_3)$ thin films have been prepared on glass substrate by using radio-frequency reactive magnetron sputtering with changing the oxygen flow ratio. The substrate temperature was kept at a fixed value of $400^{\circ}C$, and the sputtering gas and reactive gas were supplied with argon and oxygen, respectively. The oxygen partial flow ratio was varied by controlling the amount of oxygen with respect to the total mixed gases, 10%, 20%, 30%, 40%, and 50%. The optical, electrical, and structural properties of the deposited thin films were investigated by using ultraviolet-visible-near infrared spectrophotometer, Hall measurement, and X-ray diffractometer and scanning electron microscopy. The $In_2O_3$ thin film deposited at 20% of oxygen flow ratio showed an average transmittance of 86% in the wavelength range of 430~1,100 nm, an electrical resistivity of $1.1{\times}10^{-1}{\Omega}cm$. The results show that the transparent conducting films with optimum conditions can be achieved by controlling the oxygen flow ratio.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1996-2000
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• 2010

국내 시설원예 면적은 2005년 기준 52,022ha에 달하고 있으며 약 23%에 해당하는 12,000ha는 겨울철에 난방기를 가동하여 원예작물을 생산하고 있다. 농업용 난방기의 보급은 가온재배 면적의 증가와 더불어 급신장하고 있어 농업용 면세유 중 경유 공급액 약 9,260억원 중 62%에 해당하는 1,350,000톤이 시설원예 난방에 사용된 것으로 추산되고 있다. 지속적인 유가 상승으로 시설재배 농가의 경영이 악화되고 있어 최근 히트펌프를 이용한 냉난방시스템에 대한 연구가 수행되고 있다. 시설원예 냉난방에 사용되는 히트펌프의 열원은 다양하게 적용할 수 있으나 강변에 위치하고 있는 시설원예단지의 경우 연 중 풍부한 유량과 안정적인 수온을 얻을 수 있는 강변여과수는 매우 매력적인 열원이다. 본 연구에서는 시범지역으로 남강댐 하류에 위치하고 있는 진주지역의 시설원예단지와 낙동강 유역의 구미지역 시설원예단지의 두 곳에 대하여 1일 $1,000m^3$의 강변여과수 개발에 대한 조사를 수행하였다. 육안 및 현장여건에 대한 조사를 수행하고 인근 지하수 사용현황에 대한 조사를 실시하였다. 진주지역의 경우 일부 농가에서 지하수를 사용하고 있었으나 1일 8~10시간 취수에 최대 취수량은 약 $120m^3$ 정도였다. 반면, 구미지역의 경우 1999년 구미첨단원예농단 조성사업의 일환으로 양액재배에 농업용수를 공급할 목적으로 지하수 개발이 실시되었으며 최근 인근 국화축제를 개최하는 지역에서 신규로 지하수를 개발하여 사용 중이었다. 전기비저항 탐사를 실시한 결과 진주지역은 지하 약 6~17m 지점에 대수층이 존재하는 것으로 판단되었고, 구미지역은 지하 약 10~20m 지점에 대수층이 존재할 가능성이 있지만 지하 20m 지점부터는 대수층의 가능성이 높은 것으로 판단되었다. 두 지역에 각각 두 공을 시추하여 조사한 결과, 구미지역의 경우 수면높이가 지하 약 10m이고 각각 2.5m와 4.6m의 모래자갈층을 형성하고 있어 $1,000m^3$/일의 취수량 개발이 원활하지 않을 것으로 판단되었다. 한편, 진주지역은 수면높이가 지하 약 3m이고 각각 3.5m와 6.5m의 모래자갈층을 형성하고 있어 $1,000m^3$/일의 취수량 개발이 가능할 것으로 판단되었다. 현장 시추조사 및 기존관정 조사결과, 구미지역에 비하여 진주지역이 지하수 물량 확보가 상대적으로 용이하고 신규 굴착 가능지점이 다수 분포하고 있어 연구지점으로 활용하는데 유리할 것으로 판단되었다. 따라서 진주지역에 여과수열원 확보를 위해 2곳의 양수관정을 설치하고 히트펌프를 이용하여 시설원예의 냉난방을 실시할 예정이다.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.04a
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• pp.143-143
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• 2003

본 연구는 항산화효소의 효율적 생산을 위한 적절한 수확시기의 결정 및 산업적 가치를 검토하고자, 제주도에 자생하는 문주란 (Crinum asiaticum var. japonicum)에서 항산화효소 (SOD, peroxidase, catalase, APX) 활성과 isoenzyme 패턴의 계절적 변화양상을 조사하였다. SOD isoenzyme 패턴을 전기영동으로 살펴보면, 전체적으로 7개의 isoenzyme이 검출되었으며, 여름철과 겨울철에 있어서 뚜렷한 차이가 없을 뿐 아니라 일변화에 있어서도 큰 차이를 보이지 않았다. 그리고 이들 isoenzyme은 $H_2O$$_2$와 KCN에 의한 선택적 저해로부터 1개의 Mn-SOD와 6개의 CuZn-SOD로 구분할 수 있었다. Catalase는 단일밴드로 나타났으며, 여름철이 겨울철에 비해 높은 활성을 보였다. Peroxidase는 전체적으로 4개의 isoenzyme이 검출되었다. 이 중 peroxidase 1은 효소활성에는 차이가 있지만 여름철과 겨울철에 모두 검출되었으며, 3개의 isoenzyme (peroxidase 2-4)은 겨울철에만 특이적으로 검출되는 것으로 나타났다. 그리고 여름철에는 낮시간에 다소 높은 활성을 보였으며, 겨울철에는 낮시간보다는 새벽과 밤에 높은 활성을 보였다. APX는 8개의 isoenzyme이 검출되었으며, 여름철과 겨울철에 있어서 뚜렷한 차이를 보이지 않았다. 이상의 결과를 종합해보았을 때 SOD, catalase, peroxidase, APX 등 항산화효소의 산업적 생산을 위한 채취는 수확량을 감안하였을때 여름철이 적정 채취시기로 보인다. 그리고 문주란의 catalase와 peroxidase는 SOD나 APX는 달리 단일 밴드 또는 주요 밴드가 있고 높은 활성을 보여 정제시 유리하게 작용할 것으로 보인다. prospects will be also discussed.behaviors to ferromagnetic behavior was observed. Tunneling barrier called "decay length for tunneling" for the films having the thickness of Co layer from 1.4 to 1.6 nm was measured to be ranged from 0.004 to 0.021 ${\AA}$$\^$-1/.문에 기업간 관계를 연구하는 측면에서는 탐험적 연구성격이 강하다. 더 나아가 본 산업의 주된 연구가 질적이고 기업내부만을 연구했던 것에 비교하면 시초적이라고 할 수 있다. 또한 관계마케팅, CRM 등의 이론적 배경이 되고 있는 신뢰와 결속의 중요성이 재확인하는 결과도 의의라고 할 수 있다. 그리고 신뢰는 양사 간의 상호관계에서 조성될 수 있는 특성을 가진 반면, 결속은 계약관계 초기단계에서 성문화하고 규정화 할 수 있는 변수의 성격이 강하다고 할 수가 있다. 본 연구는 복잡한 기업간 관계를 지나치게 협력적 측면에서만 규명했기 때문에 많은 측면을 간과할 가능성이 있다. 또한 방법론적으로 일방향의 시각만을 고려했고, 횡단적 조사를 통하고 국내의 한 서비스제공업체와 관련이 있는 컨텐츠 공급파트너만의 시각을 검증했기 때문에 해석에서 유의할 필요가 있다. 또한 타당성확보 노력을 기하였지만 측정도구 면에서 엄격한 개발과정을 준수하지는 못했다. 향후에는 모바일 컨텐츠 파트너의 기업의 특성을 조사하여 관계성 변수와의 상호관련연구를 진행할 필요가 있다. 관계기간, 의존성, 거래처의 단/복수여부, 서비스 범주 등의 제반 변수를 고려하여 이러한 변수가 양사와의 관계성 변수에 어떤 영향이 있는가를 검증할 필요가 있다. 또한 신뢰, 결속 등 다차원의 개념

• YAKHAK HOEJI
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• v.51 no.2
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• pp.150-156
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• 2007

Some flavonoids have spasmolytic activities in various smooth muscles, but structure-activity relationships on their spasmolytic activity and its mechanism are unclear. In this study, effects of flavones (flavone and apigenin) and flavonols (quercetin and rutin) on the rat ileal smooth muscle contraction were studied in vitro and in vitro. In the electric stimulation-induced contraction, all of four flavonoids inhibited concentration-dependently the rat ileal smooth muscle contraction induced by electric stimulation (10 mV, 0.1 cps, 0.1 msec duration), IC$_{50}$ of quercetin, apigenin, flavone and rutin were 0.98${\times}$10$^{-5}$, 1.20${\times}$10$^{-5}$, 1.55${\times}$10$^{-5}$ and 1.85${\times}$10$^{-5}$ M, respectively. Flavonoids at a concentration of 2${\times}$10$^{-5}$ M also significantly inhibited the anaphylactic contraction and decreased concentration-dependently the mast cell degranulation by anaphylactic reaction, IC$_{50}$ of quercetin, apigenin, flavone and rutin were 4.0${\times}$10$^{-5}$, 7.5${\times}$10$^{-5}$, 8.0${\times}$10$^{-5}$ and 9.5${\times}$10$^{-5}$ M, respectively. These results indicated that flavones and flavonols inhibited the rat ileal smooth muscle contraction induced by electric stimulation because of their antagonism against acetylcholine and have spasmolytic activities on anaphylactic contraction which may be due to their mast cell-stabilizing activities. Furthermore, double bond of C$_{2,3}$ in benzene ring of flavonoids may be important in the their antispasmodic activities on the rat ileal smooth muscle contraction induced by electric stimulation and anaphylactic reaction.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.10 no.3
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• pp.237-242
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• 2016

The major advantage of slip-ring technology in Spiral CT is that it facilitates continuous rotation of the x-ray tube, so that volume data can be acquired from a patient quickly. Not only for such a fast scan, but also for the dose reduction purpose, high signal-to-noise ratio and fast data acquisition system is required. In this study, we have built a multi-channel photodetector and multi-channel data acquisition system for CT application. The detector module consisted of CdWO4 crystal and Si photodiode in 16 channels. For the performance test of the preamplifier stage, both the transimpedance and switched integrator types are optimized for the photodetector modules. Switched integrator showed better noise performance in the limited bandwidth which is suitable for the current CT application. The control sequence for data acquisition and 20 bit ADC is designed with VHDL(Very High Speed Integrated Circuit Hardware Description Language) and implemented on FPGA(Field Programmable Gate Array) chip. Our Si photodiode detector module coupled to CdWO4 crystal showed comparable signal with other commercially available photodiode for CT. Switched integrator type showed higher SNR but narrower bandwidth compared to transimpedance preamplifier. Digital hardware is designed by FPGA, so that the control signal could be redesigned without hardware alteration.

• Korean Journal of Food Science and Technology
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• v.29 no.6
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• pp.1158-1165
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• 1997

This study was designed to investigate the changes in microflora and enzyme activities of traditional kochujang during aging, which was prepared with a meju fermented for various periods of time. The number of bacteria was highest in all samples after 30 days of fermentation at $20^{\circ}C$, while that of mold in kochujang prepared with a 40-day- or 60-day-fermented meju was highest at 15th day of aging when yeast appeared. The activities of carbohydrases and proteases were highest in kochujang prepared with a 40-day-fermented meju followed by a 60-day-fermented meju. These results suggest that kochujang prepared with a meju aged for 40 days had the highest quality in terms of physicochemical, microbiological and enzyme activities of kochujang during fermentation.

• Fire Science and Engineering
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• v.34 no.3
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• pp.67-75
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• 2020

In this study, the risk of heat generation due to normal and overload currents that vary with the abnormal loosening angle of wire-connecting bolts were identified. The risks were analyzed based on the thermal characteristics to minimize the carbonization accidents of terminal blocks inside distribution panels typically used in industrial sites. We applied a method for measuring the heating temperature and temperature variations in the terminal blocks in real-time by installing a resistance temperature detector sensor board in the terminal block. The experimental results showed that the terminal block model with a low-rated current exhibited a higher heating temperature, thus, confirming the need to select the terminal block capacity based on load currents. Additionally, the higher the rated current of the terminal block with a high-rated current and the higher the degree of loosening, the faster the carbonization point. Such heating temperature monitoring enabled real-time thermal temperature measurement and a step-by-step risk level setting through thermal analysis. The results of the measurement and analysis of carbonization risks can provide a theoretical basis for further research regarding the risk of fire due to carbonization. Furthermore, the deterioration measurement method using the temperature sensor board developed in this study is widely applicable to prevent fires caused by poor electrical contact as well as risk-level management.

• Fire Science and Engineering
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• v.34 no.3
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• pp.76-84
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• 2020

Most outlet fires occur around plug pins and plug pin receivers. However, no research has been conducted on ignitions at power connection points. This study confirms the possibility of ignition after incomplete connection, using a stranded wire, to the power connection point of an outlet. The experiment was divided into basic and reproducing experiments. The basic experiment confirmed the possibility of ignition according to the number of wire strands connected to the power connection point, and it identified the characteristics of the residue after the fire. In the reproducing experiment, lamps, vacuum cleaners, and heaters were connected to an outlet to check if the ignition at the connection advanced into a fire. The fire advanced due to the heat and arc generated at the connection point, and partial losses were identified in the U-type holder and clip. Accordingly, the results demonstrate that a fire may occur when the stranded wire is incompletely connected to the outlet. Moreover, it was confirmed that the cause of a fire can be determined based on the characteristics of the residue.

• Journal of Gifted/Talented Education
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• v.25 no.1
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• pp.119-138
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• 2015

This study analyzed the academic achievements on above-level testing of mathematics, physics, chemistry, and English in newly entering students of science specialized high schools. It can be expected that newly students of science high specialized schools have reached ceiling level in the middle school mathematics and science academic scores. Above-level testing(or off-level testing) is a test tool used to evaluate student's ability which are above-grade level. In this study, above-level testing tools were used to develop the same type examination paper of the 2013 Korean College Scholastic Ability Test(CSAT) in mathematics, physics, chemistry, and English. The conclusions of this study were as follow: First, the academic achievement level of science specialized high school freshmen were higher the average level of general high school senior because that over 50% of them are within the 5 grade of CSAT in mathematics, physics, and chemistry. In English, 19.3% science specialized high school freshmen have reached within the 5 grade of CSAT. Second, as a result of examining characteristics of academic achievement with respect to units of subjects, in mathematics, it was showed that the academic achievement of 'continuity and limit of a function' unit was higher, 'statistics' unit was lower. In physics, the academic achievement of 'Electricity and Magnetism' unit was higher, 'Waves and particles' unit was lower. In chemistry, the academic achievement of 'compounds in life' unit was higher, 'Air' unit was lower. In English, the academic achievement of 'practical sentence' of reading area was higher, 'Sentence' of writing area was lower. In conclusion, above-level testing provided a good strategy for identifying and determining appropriate programming interventions for gifted students who are two or more grade levels above their age-mates in achievements, aptitude, or ability.