• 한국결정성장학회지
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• 제33권6호
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• pp.255-260
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• 2023

분자 단위의 폭발물질을 탐지하기 위하여, 고감도 응답성 센서의 개발이 요구되고 있다. 2차원 반도체는 얇은 적층형 구조를 가져 전하 캐리어가 축적될 수 있어, 전하 캐리어의 급격한 신호 변조 특성을 기대할 수 있다. WSe₂ 반도체 소재의 TNT(Trinitrotoluene) 폭발물질에 대한 탐지 효용성을 연구하기 위해, CVD(Chemical Vapor Deposition) 공정을 이용해 WSe₂ 박막을 합성하여 FET(Field Effect Transistors)을 제작하였다. 라만 분석과 FT-IR(Fourier-transform infrared) 분광 결과는 TNT 분자의 흡착과 WSe₂ 결정질의 구조적 전이 분석 정보를 나타내었다. 또한, WSe₂ 표면의 TNT 분자 흡착 전후의 전기적 특성을 비교하였다. TNT 도포 전, WSe₂ FET에 백 게이트 바이어스로 -50 V를 인가함에 따라 0.02 μA의 최대 전류 값이 관측되었고, 0.6%(w/v) TNT 용액을 도포하였을 때 Drain 전류는 p-type 거동을 보이면서 0.41 μA의 최대 전류 값을 기록하였다. 이후 On/Of f Ratio 및 캐리어 이동도, 히스테리시스를 추가적으로 평가하였다. 본 연구에서는 WSe₂의 TNT 분자에 대한 고감도와 신속한 응답성을 통해 폭발물질 탐지 센서 소재로서의 가능성을 제시하였다.

• 한국응용곤충학회지
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• 제43권2호
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• pp.163-168
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• 2004

광대노린재(P lewisi)의 실내 계대사육법을 확립하기 위해 먼저 실내에서의 생식행동을 구명하였다. 고온장일조건($25^{\circ}C$, 16Lㆍ8D)의 사육실에서 사육하면서 교미행동과 다중교미가 산란성에 미치는 영향에 대해 조사하였는데 광대노린재 성충의 교미는 성충 일령별로 9일째부터 시작되어 17일 이후는 교미율이 증가(60% 이상)하여 성충 21일째 84.5%로 피크를 이루였다. 광대노린재의 교미행동과정은 탐색배회, 접근, 더듬이접촉, 올라타기, 복부말단접근, 교미(끝에 끝 자세)를 취하는 것으로 조사되었다. 수컷은 교미행동 전 과정에서 능동적이었으며 또한 암컷에게 올라타기를 하기 전까지 마찰음을 내였으나 대부분의 암컷은 교미에 수동적이었다. 교미가 이루어지는 시간은 조명 후 1시간 내에 69% ,2시간 8% ,3시간 6% ,4시간 16% ,5시간 1%로 거의 4시간 내에는 교미가 이루어지는 것으로 관찰되었다. 암컷의 재교미는 첫 교미 후7일 동안 20% 정도 이루어졌으나 수컷의 재교미율은 암컷보다 월등히 높았다. 한편 암컷은 1회 교미 후 시간이 경과함에 따라 산란된 알의 부화율이 감소하였으나 재교미를 함으로서 산란된 알의 부화율이 향상되었고 수컷은 교미횟수가 증가할수록 산란된 알의 부화율이 감소하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.189-189
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• 2016

Recently, many researchers have shown an increased interest in colloidal quantum dots (QDs) due to their unique physical and optical properties of size control for energy band gap, narrow emission with small full width at half maxima (FWHM), broad spectral photo response from ultraviolet to infrared, and flexible solution processing. QDs can be widely used in the field of optoelectronic and biological applications and, in particular, colloidal QDs based light emitting diodes (QDLEDs) have attracted considerable attention as an emerging technology for next generation displays and solid state lighting. A few methods have been proposed to fabricate white color QDLEDs. However, the fabrication of white color QDLEDs using single QD is very challenging. Recently, hybrid nanocomposites consisting of CdTe/ZnO heterostructures were reported by Zhimin Yuan et al.[1] Here, we demonstrate a novel but facile technique for the synthesis of CdTe/ZnO/G.O(graphene oxide) quasi-core-shell-shell quantum dots that are applied in the white color LED devices. Our best device achieves a maximum luminance of 484.2 cd/m2 and CIE coordinates (0.35, 0.28).

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.244.1-244.1
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• 2015

The Ag Nanowire is one of the materials that are widely studied as alternatives to ITO and is available for large area, low cost process and the flexible transparent electrode. However, Ag nanowire can have the problem of a lack of stability at high temperatures, making this impossible to form a film. Using a structure of ITO/AgNW/ITO in photodetector device, we improved the properties of the ITO in the IR region and improved the thermal stability of the AgNW. The structure of ITO/AgNW/ITO has a high transmittance value of 89% at a wavelength of 900 nm and provide a good electrical property. The AgNWs embedded ITO film has a high transmittance, this is because of the light scattering from the AgNW. The thermal stability of the developed ITO/AgNWs/ITO films were investigated and found AgNWs embedded ITO films posses considerable high stability compared to the solo AgNWs on the Si surface. The ITO/AgNWs/ITO device showed a improved photo-response ratio compared to those of the conventional TC device in IR region. This is attributed to the high transmittance and low sheet resistance. We suggest an effective design scheme for IR-sensitive photodetection by using an AgNW embedded ITO.

• Journal of Animal Science and Technology
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• 제53권3호
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• pp.261-268
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• 2011

The increasing demand of the crops (soybean and corn) for biofuel production has increased the focus of the animal nutritionists to look for alternative feeds, which are economic and environmental friendly. To identify microalgae as suitable candidate as an alternative feed, growth response of Chlorella vulgaris was studied under varying concentrations of carbon dioxide (0.07, 1.4, 3.0 and 5.0%) and photon densities (39.19, 72.97, 105.41, 116.22, 135.14, $175.68\;{\mu}mol/m^2/s$) by employing a photo-bioreactor. Swine wastewater was also investigated as nutritional source to economize the biomass production. Results showed that the higher biomass production was found to be at 3.0% $CO_2$ compared to other $CO_2$ concentrations. However, no difference in biomass production was found at $105.41\;{\mu}mol/m^2/s$ and above photon densities with 12 h of photoperiodicity. It was observed that C. vulgaris could easily grow in 200 times diluted swine wastewater and growth was found to be similar with that of artificial medium. Provided the conducive conditions for optimal growth, it has also the potentiality of depleting ammonia nitrogen ($NH_4$-N) and orthophosphate ($PO_4^{3-}$-P) completely from the wastewater after 3~4 days of cultivation. Thus, growing C. vulgaris would not only solve the problem of animal feed, but also help in biological $CO_2$ mitigation and wastewater treatment.

• 농촌계획
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• 제12권2호
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• pp.57-64
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• 2006

The experiment was carried out to determine the distribution of total coliform the translocation of heavy metals and the salt accumulation in soils following the supply of ground water, the domestic wastewater and the ultraviolet treatment of domestic wastewater during the spinach and the chinese cabbage cultivation. There were not much changes in the Total-N, Total-P and cations in soils following the ultraviolet treatment of the domestic wastewater. However, the density of total coliform was dramatically reduced from 894MPN/100mL to 5MPN/100mL. The diagnosis of composition of soil after the harvest of chinese cabbages and spinach has shown that the concentration of Na$^+$ was 3-4 times higher in plot using domestic wastewater than in plot using ground water. When domestic wastewater and ground water were used in growing spinach md chinese cabbage at 50% each, the application of chemical fertilizers reduced about 25% to 50% compared to the criteria set down by the Rural Development Administration and there was not significant difference in terms of harvest. Using non-ultraviolet treatment of domestic wastewater directly on spinach and chinese cabbage has resulted in excessive density of total coliform at 25,000MPN/100mL. Even when ultraviolet treatment, the density was still high at 2,000MPN/100mL. The high density of total coliform even following ultraviolet treatment of domestic wastewater is considered to be caused by photo-reactivation of micro-organism. When reusing domestic wastewater, the application of sterilization such as ultraviolet, ultrasonic and electron-beam for public health and hygiene reasons may provide safe supply of agricultural water.

• The Korean Journal of Physiology and Pharmacology
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• 제2권1호
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• pp.63-68
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• 1998

Nitric oxide (NO)-mediated relaxation in vascular smooth muscle involves not only activation of guanylate cyclase but also hyperpolarization of the membrane. It has been shown that depolarization decreases the [$Ca^{2+}$] sensitivity of myosin light chain kinase in arterial smooth muscle, and nitric oxide (NO)-mediated relaxation was attenuated in this situation. However, why potassium inhibits or attenuates the action of EDRF/NO is not clear. Therefore, we investigated the magnitude of relaxation and cGMP contents using measures known to release NO, such as photorelaxation, photo activated NO-mediated relaxation, and NO-donor (SNP)-mediated relaxation in porcine coronary arterial rings in which contractile conditions were made by different degree of depolarization, i.e., contraction in response to U46619 or U46619 plus KCl. In all cases, the magnitude of relaxation was significantly greater (P＜0.05) in U46619-contracted rings than in U46619+KCl-contracted ones. Although accumulation of cGMP was evident with three measures employed in the present study, no difference was found in cGMP contents between U46619 and U46619+KCl conditions, indicating that the diminished relaxation in KCl containing solution is cGMP-independent mechanism(s). To understand this further, cytosolic $Ca^{2+}$ changes due to NO were compared in rat thoracic aorta by exploiting photoactivated NO using streptozotocin (STZ) that was contracted with either NE or KCl. Fura-3 $[Ca]_{cyt}$ signal caused by NO was small and transient in high $K^+$-, but large and sustained in NE-contracted aorta. The inhibitory potency of STZ expressed in terms of $IC_{50}$ was 5.14 and 3.88 ${\mu}M$ in NE and in high $K^+$, respectively. These results suggest that modification of the cellular mobilization of $Ca^{2+}$ rather than cGMP levels may be an important mechanism for the NO-mediated relaxation when vascular membrane is depolarized, such as atherosclerosis and hypertension.

• 정보보호학회논문지
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• 제23권6호
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• pp.1069-1086
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• 2013

최근에 발생하는 웹 사이트 해킹은 기업의 이미지와 평판에 악영향을 끼치는 큰 위협이 되고 있다. 이러한 웹 사이트 변조 행위는 해커의 정치적인 동기나 성향을 반영하기도 하므로, 행위에 대한 분석은 해커나 해커 그룹을 추적하기 위한 결정적인 단서를 제공할 수 있다. 웹 사이트에 남겨진 특정한 메시지나 사진, 음악 등의 흔적들은 해커를 추적하기 위한 단서를 제공할 수 있고, 인코딩 방법과 해커가 남긴 메시지에 사용된 폰트, 트위터나 페이스북 같은 해커의 SNS ID 또한 해커의 정보를 추적하는데 도움을 준다. 본 논문에서는 zone-h.org의 웹 해킹 사례들로부터 특성들을 추출하고, CBR(Case-Based Reasoning) 알고리즘을 적용하여 침해사고 프로파일링 시스템을 구현하였다. 해커의 흔적과 습관에 관한 분석 및 연구는 추후 사이버 수사에 있어 공격 의도를 파악하고 그에 따른 대응책을 마련하는 데 있어 IDSS(Investigation Detection Support System)로써 중요한 역할을 기대 할 수 있으리라 본다.

• 한국전기전자재료학회논문지
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• 제30권12호
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• pp.806-811
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• 2017

An all-transparent ultraviolet (UV) photodetector was fabricated by structuring $p-NiO/n-SnO_2/ITO$ on a glass substrate. $SnO_2$ is an important semiconductor material because of its large bandgap, high electron mobility, high transmittance (as high as 80% in the visible range), and high stability under UV light. For these reasons, $SnO_2$ is suitable for a range of applications that involve UV light. In order to form a highly transparent p-n junction for UV detection, $SnO_2$ was deposited onto a device containing NiO as a high-transparent metal conductive oxide for UV detection. We demonstrated that all-transparent UV photodetectors based on $SnO_2$ could provide a definitive photocurrent density of $4nA\;cm^{-2}$ at 0 V under UV light (365 nm) and a low saturation current density of $2.02nA{\times}cm^{-2}$. The device under UV light displayed fast photoresponse with times of 31.69 ms (rise-time) and 35.12 ms (fall-time) and a remarkable photoresponse ratio of 69.37. We analyzed the optical and electrical properties of the $NiO/SnO_2$ device. We demonstrated that the excellent properties of $SnO_2$ are valuable in transparent photoelectric device applications, which can suggest various routes for improving the performance of such devices.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1668-1670
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• 2002

Since more than two decades, the conventional PD detecting systems have been employed in order to detect the partial discharges occurring inside the HV power apparatus for their diagnosis by use of different type of detection such as acoustic and UHF detection method. Regardless of their wide on-site application, a certain number of technical inconveniences have been disclosed as follows : multistage amplification. large volume, susceptible to external noise and high price. In this respect, the optical measurement techniques are widely proposed in these days in this concerned field ascribed to the following advantages : immune to external EMI noise and broad band response of the Pockels cell covering from DC to GHz. However, the reliability of several proposed techniques enabling to measure the electric field inside the large high power apparatus has not yet been well approved In this work, an optical measuring system, based on the Pockels effect, has been developed for measuring the field variation due to the corona discharges occurring in air and in oil. This system consists of He-Ne laser, single mode optical fiber, multi mode optical fiber, polarizing film, Y-cut LiNbO3 cell, photo detector, digital oscilloscope and personal computer with GPIB. For this purpose, optical probe has been specially designed and realized and put into the needle-plane electrode. Afterward, same measurement is carried out in oil. We demonstrate the characteristic of the optical measuring system and the measurement results.