• 한국잠사곤충학회지
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• 제43권2호
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• pp.77-82
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• 2001

DFB는 IGR계통의 약제로서 나비목 곤충류에 널리 사용되고 있으며, 주로 알려진 효과는, DFB 본래의 chitin 합성 억제 특성이외에(Post and Vincent, 1973), DFB의 물질분비능력억제 효과가 보고되어 있다(Nakagawa et al., 1996). 또 다른 한편으로 DBF가 juvenile hormone(JH)의 길항으로 작용하고 있다고 추정되고 있다. 따라서 본 실험은 DFB가 누에의 발육성장에 미치는 영향을 알아보기 위하여 DFB를 2.5$\times$$10^{-1}$ $\mu\textrm{g}$/$\mu$l, 2.5$\times$$10^{-2}$ $\mu\textrm{g}$/$\mu$l, 2.5$\times$$10^{-3}$$\mu\textrm{g}$/$\mu$l의 농도로 누에에 처리하였다. 본 조사에서는 DFB가 누에의 실샘에 미치는 영향을 조사하기 위해, SEM을 이용한 미세구조 분석 및 외부형태 변화 그리고 DFB처리에 의한 실샘의 건물중량, 수분량 등을 알아보았다. 실샘의 발육정도는 DFB의 처리농도에 따라서는 큰 차이가 없었고, DFB의 처리시기와 처리 회수에 따라 많은 차이가 있었다. 처리기간이 길수록 실샘의 건물중량은 현격히 줄었으며, 반대로 실샘의 수분함량 은 증가하였다. 특히 5령 1일, 3일 처리구에서 실샘의 수분함량이 80% 이상으로 증가되어 수분생리대사에 영향을 미쳤고 그 결과 실샘 물질의 물리성이 변하여 결국 정상적인 토사가 이루어지지 않아 불결견잠으로 된 원인이었다. DFB를 처리한 누에 실샘의 외부 특징은 중부 실샘에 백색경화현상이 나타났으며 이 부위를 전자현미경으로 확인한 결과 실샘의 세포막이 정상과는 달리 조밀하여 실샘 세포 내에서 합성된 견단백질이 분비가 되지 않고 실샘 내에 축적되었다.

• 광물과 암석
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• 제33권3호
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• pp.195-214
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• 2020

삼광 금-은 광상은 과거 한국에서 가장 큰 금-은 광상들 중의 하나였다. 이 광상은 선캠브리아기의 변성퇴적암류내에 발달된 열극대를 충진한 8개조의 석영맥으로 구성된 조산형 금-은 광상이다. 이 광상에서 함 티타늄 광물로는 설석, 티탄철석 및 금홍석이며 설석과 티탄철석은 모암에서만 산출되나 금홍석은 모암과 엽리상 석영맥에서 산출된다. 이들 광물들은 모암에선 흑운모, 백운모, 녹니석, 백색운모, 모나자이트, 저어콘 및 인회석과 엽리상 석영맥에선 백색운모, 녹니석 및 유비철석 등과 함께 산출된다. 설석은 최대 3.94 wt.% (Al₂O₃), 0.49 wt.% (FeO), 0.52 wt.% (Nb₂O₅), 0.46 wt.% (Y₂O₃) 및 0.43 wt.% (V₂O₅) 값을 갖는다. 이 설석은 0.06~0.14 (Fe/Al 비) 값으로 변성기원의 설석이고 X_Al (=Al/Al+Fe³⁺+Ti) 값이 0.06~0.15 값으로 저 함량 알루미늄 설석에 해당된다. 티탄철석은 최대 0.07 wt.% (ZrO₂), 0.12 wt.% (HfO₂), 0.26 wt.% (Nb₂O₅), 0.04 wt.% (Sb₂O₅), 0.13 wt.% (Ta₂O₅), 2.62 wt.% (As₂O₅), 0.29 wt.% (V₂O₅), 0.12 wt.% (Al₂O₃), 1.59 wt.% (ZnO)로써 As₂O₅ 함량이 높게 산출된다. 금홍석의 화학조성은 모암과 엽리상 석영맥에서 각각 최대 0.35 wt.%, 0.65 wt.% (HfO₂), 2.52 wt.%, 0.19 wt.% (WO₃), 1.28 wt.%, 1.71 wt.% (Nb₂O₃), 0.03 wt.%, 0.07 wt.% (Sb₂O₃), 0.28 wt.%, 0.21 wt.% (As₂O₅), 0.68 wt.%, 0.70 wt.% (V₂O₃), 0.48 wt.%, 0.59 wt.% (Cr₂O₃), 0.70 wt.%, 1.90 wt.% (Al₂O₃), 4.76 wt.%, 3.17 wt.% (FeO)로써 엽리상 석영맥의 금홍석에서 HfO₂, Nb₂O₃, As₂O₅, Cr₂O₃, Al₂O₃ 및 FeO 원소들의 함량이 모암의 금홍석보다 높지만 WO₃ 원소의 함량은 낮다. 이 미량원소들은 모암의 금홍석[(Fe³⁺, Al³⁺, Cr³⁺) + Hf⁴⁺+(W⁵⁺, As⁵⁺, Nb⁵⁺) ⟵⟶; 2Ti⁴⁺+ V⁴⁺, 2Fe²⁺+(Al³⁺, Cr³⁺) + Hf⁴⁺+(W⁵⁺, As⁵⁺, Nb⁵⁺) ⟵⟶ 2Ti⁴⁺+2V⁴⁺], 엽리상 석영맥의 금홍석 [(Fe³⁺, Al³⁺) + As⁵⁺ ⟵⟶ Ti⁴⁺+ V⁴⁺, (Fe³⁺, Al³⁺) + As⁵⁺ ⟵⟶ Ti⁴⁺+Hf⁴⁺, 4(Fe³⁺, Al³⁺) ⟵⟶ Ti⁴⁺+(W⁵⁺, Nb⁵⁺) + Cr³⁺]로써 치환관계가 있었다. 이들 자료를 근거로, 모암내 산출되는 설석, 티탄철석 및 금홍석은 광역변성작용 동안 모암광물들의 변질 시 광물내 존재했던 W⁵⁺, Nb⁵⁺, As⁵⁺, Hf⁴⁺, V⁴⁺, Cr³⁺, Al³⁺, Fe³⁺, Fe²⁺ 등과 같은 양이온들의 재 용해 및 농집에 의해 형성되었다. 그후 계속된 연성전단 시 엽리상 석영맥내 금홍석은 열수 용액의 유입에 따른 백색운모와 녹니석의 모암변질작용에 의한 양이온들의 재 용해 및 재 농집과 더불어 초기에 형성된 설석, 티탄철석 및 금홍석과의 반응에 의해 기존에 이들 광물내에 존재하였던 Nb⁵⁺, As⁵⁺, Hf⁴⁺, Cr³⁺, Al³⁺, Fe³⁺, Fe²⁺과 같은 양이온들의 재농집에 의해 형성된 것으로 생각된다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2018년도 춘계학술대회 논문집
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• pp.50.2-50.2
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• 2018

The demand for steady and dependable power sources is very high in the field of sustainable energy because of the limited amount of fossil fuels reserves. Among several sustainable alternatives, solar energy may be the most efficient solution because it constitutes the largest renewable energy source. So far, the only practical way to store such large amounts of energy has been to use a chemical energy carrier likewise a fuel. In various solar energy to power conversion systems, the photoelectrochemical (PEC) splitting of water into hydrogen and oxygen by the direct use of solar energy is an ideal process. It is a renewable method of hydrogen production integrated with solar energy absorption and water electrolysis using a single photoelectrode. Previous studies on photoelectrode films for PEC water splitting cells have been mainly focused on synthesizing oxide semiconductors with wide band gaps, such as TiO2(3.2eV), WO3(2.8eV), and Fe2O3(2.3eV). Unfortunately, these pristine oxide photoanodes without any catalysts have relatively low photocurrent densities because of the inherent limitation of insufficient visible light absorption due to the wide bandgap. Specifically, there is a tradeoff between high photocurrent and photoelectrochemical corrosion behavior, which is representative of figures of meritf or PEC materials.

• 한국세라믹학회지
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• 제48권3호
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• pp.257-262
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• 2011

Dependencies of dielectric properties on $MgTa_2O_6$, $MgNb_2O_6$, and $MgWO_4$ (Mg-based ceramics) fillers of the polystyrene (PS) matrix composites were investigated as a function of frequency. With increasing frequency from 1 GHz to 7.3 GHz, the dielectric constant (K) of the composites was not changed significantly, while the dielectric loss (tan${\delta}$) of the composites was slightly decreased. The K, tan${\delta}$, and temperature coefficient of resonant frequency (TCF) of the composites were dependent on the type and amount of ceramics at 11 GHz. Also, several theoretical models have been employed to predict the effective dielectric constant of the composites and the results were compared with experimental data. Typically, a K value of 6.67, tan${\delta}$ of $0.56{\times}10^{-3}$, and TCF of -4.99 $ppm/^{\circ}C$ were obtained for the PS composites with 0.4 volume fraction of $MgNb_2O_6$ at 11 GHz.

• 한국재료학회지
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• 제33권5호
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• pp.195-204
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• 2023

Micro-electronic gas sensor devices were developed for the detection of carbon monoxide (CO), nitrogen oxides (NO_x), ammonia (NH₃), and formaldehyde (HCHO), as well as binary mixed-gas systems. Four gas sensing materials for different target gases, Pd-SnO₂ for CO, In₂O₃ for NO_x, Ru-WO₃ for NH₃, and SnO₂-ZnO for HCHO, were synthesized using a sol-gel method, and sensor devices were then fabricated using a micro sensor platform. The gas sensing behavior and sensor response to the gas mixture were examined for six mixed gas systems using the experimental data in MEMS gas sensor arrays in sole gases and their mixtures. The gas sensing behavior with the mixed gas system suggests that specific adsorption and selective activation of the adsorption sites might occur in gas mixtures, and allow selectivity for the adsorption of a particular gas. The careful pattern recognition of sensing data obtained by the sensor array made it possible to distinguish a gas species from a gas mixture and to measure its concentration.

• 한국재료학회지
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• 제34권5호
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• pp.235-241
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• 2024

Gas identification techniques using pattern recognition methods were developed from four micro-electronic gas sensors for noxious gas mixture analysis. The target gases for the air quality monitoring inside vehicles were two exhaust gases, carbon monoxide (CO) and nitrogen oxides (NO_x), and two odor gases, ammonia (NH₃) and formaldehyde (HCHO). Four MEMS gas sensors with sensing materials of Pd-SnO₂ for CO, In₂O₃ for NO_X, Ru-WO₃ for NH₃, and hybridized SnO₂-ZnO material for HCHO were fabricated. In six binary mixed gas systems with oxidizing and reducing gases, the gas sensing behaviors and the sensor responses of these methods were examined for the discrimination of gas species. The gas sensitivity data was extracted and their patterns were determined using principal component analysis (PCA) techniques. The PCA plot results showed good separation among the mixed gas systems, suggesting that the gas mixture tests for noxious gases and their mixtures could be well classified and discriminated changes.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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• pp.99-102
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• 1997

An electronic nose system is an instrument designed far mimicking human olfactory system. It consists generally of gas (odor) sensor array corresponding to olfactory receptors of human nose and artificial neural network pattern recognition technique based on human biological odor sensing mechanism. Considerable attempts to develop the electronic nose system have been made far applications in the fields of floods, drinks, cosmetics, environment monitoring, etc. A portable electronic nose system has been fabricated by using oxide semiconductor gas sensor array and pattern recognition technique such as principal component analysis (PCA) and back propagation artificial neural network The sensor array consists of six thick film gas sensors whose sensing layers are Pd-doped WO$_3$ Pt-doped SnO$_2$ TiO$_2$-Sb$_2$O$_3$-Pd-doped SnO$_2$ TiO$_2$-Sb$_2$O$_{5}$-Pd-doped SnO$_2$+Pd filter layer, A1$_2$O$_3$-doped ZnO and PdCl$_2$-doped SnO$_2$. As an application the system has been used to identify CO/HC car exhausting gases and the identification has been successfully demonstrated.d.

• 한국도로학회논문집
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• 제17권3호
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• pp.59-68
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• 2015

PURPOSES : This study suggests the application of glow line marking technology for reducing traffic accidents at nighttime. METHODS : In this study, using a statistical analysis, we analyzed the characteristics of traffic accidents occurring at nighttime. Next, the strength, weakness, opportunity, and threat (SWOT) factors were derived based on a current-status analysis of glow line marking technology and road environments. An SO strategy, ST strategy, WO strategy, and WT strategy were established in accordance with the four SWOT factors. RESULTS : This study suggests that the following strategies should be promoted to apply glow line marking technology to a road environment: 1) an activation strategy for the technological development of glow line markings for a new paradigm in reducing traffic accidents, 2) a benefit enhancement strategy applying glow line marking technology in places where nighttime traffic accidents frequently occur, 3) a strategy for the expansion of glow line marking by replacing streetlights, and 4) a strategy for enhancing road applications through the development of various line marking methods in consideration of both performance and costs. CONCLUSIONS : The application of glow line markings in a road environment can contribute to a reduction of traffic accidents at nighttime, and aid energy savings from the replacement of streetlights.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1149-1150
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• 2006

The oxidation of (W,Mo)$Si_2$ powders has been investigated at 400, 500 and $600^{\circ}C$ for 12.0 hours in air. It was shown that the low temperature oxidation resistance of (W,Mo)$Si_2$ was worse than that of $MoSi_2$, and they showed great changes in mass, volume and colour. Especialy at $500^{\circ}C$, the amount of volume expansion of (W,Mo)$Si_2$ was as high as about $7\sim8$ times and color changed from black to yellow after 4.0h with $MoO_3$, $WO_3$, (W,Mo)$O_3$ and amorphous $SiO_2$ as main reaction products. The mass gain and oxidation rate were relatively slower at $400^{\circ}C$ and $600^{\circ}C$ than that at $500^{\circ}C$.

• 가정과삶의질연구
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• 제14권2호
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• pp.127-138
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• 1996

The purpose of this study is to show farm women's stress under productive activity role multiple overload through family characteristic (pattern and number) and characteristic(type working time and involvement proportion) of productive activity. The outline of the study is as follow; 1. Stress by pattern and number of a family is highest in a four generation family and increases according as the number of the family increases. 2. The characteristic of productive activity : 1) Stress based on type of productive activity is highest in Type III of the most multiple overload roles. 2) in light of stress based working time area of household task activity is in inverse proportion to working time but area of farming and wage earning activity are approximately in direct proportion to it. The two-way ANOVA analysis show that stress in Type I of area of household task increases but in Type IV it decreases as working time increases 3) In stress based on involvement proportion to it. The wo-way ANOVA analysis show that stress in Type I of area of household task increases but in Type IV it decreases as working time increases. 3) In stress based on involvement proportion in three as working time increases 3). In stress based on involvement proportion in three activity areas the more the involvement proportion the less of the stress : an inverse ratio.