• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 하계학술대회 논문집
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• pp.227-230
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• 1990

The addition of titanium has come to produce an increase in the conductivity of ${\alpha}-Fe_2O_3$ and has been shown NTC ( negative temperature coefficient ) characteristics. Titanium enters the ${\alpha}-Fe_2O_3$ lattice substitutionally as $Ti^{4+}$,thus producing an $Fe^{2+}$ and maintaining the average charge per cation at three. Thus the $Fe^{2+}$ acts as a donor center with respect to the surrounding $Fe^{3+}$ ions. The sintering temperature, compacting pressure and sintering tire have an effect on the electrical properties. C-V and other properties have been measured on polycrystalline samples of ${\alpha}-Fe_2O_3$ containing small deviations from stoichiometry and small amounts of added Titanium. This measurment was made in the course of an investigation of the NTC mechanism in oxides whose cations have a partially filled d-level. C-V and frequency properties have been applied to the measurement of the trap barrier properties at the grain boundary. The double Schottky barrier at the grain boundary is the major cause of the NTC mechanism in NTC thermistor of ${\alpha}-Fe_2O_3$ containing N-type impurity.

• Applied Biological Chemistry
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• 제44권4호
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• pp.257-261
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• 2001

조직학적으로 피혁을 구성하고 있는 콜라겐 단백질의 성분은 미생물의 생육 조건 여부에 따라 수분을 비롯한 여러 가지 양질의 영양원을 가지고 있다. 본 연구에서는 피혁 제조 공정 중 탄닝 공정에서 항균제의 종류별 활용 실험을 통해서 피혁의 층별 항균성 효과, 세탁에 대한 항균 지속성 연구, 가죽의 유연성(softness)을 부여하기 위하여 사용하는 가지제(fatliquor)의 종류가 항균성에 미치는 영향 등을 검토하였다. 연구 결과 피혁의 층별 실험에서는 동일한 항균제를 처리시 grain layer>middle layer>flesh layer 순으로 항균성이 우수함을 알 수 있었다. 세탁에 대한 항균 지속성 실험에서는 세탁 횟수에 비례해서 향균력이 저하되는 일반적인 경향을 나타내었는데, 특별히 OITZ 계통의 항균제는 TCMTB 및 CMK 계통의 항균제보다 그 감소폭이 적음을 알 수 있었다. 가지제가 항균성에 미치는 영향을 검토한 결과 sulfated fatliquor(황산화 가지제)가 phosphated fatliquor(인산화 가지제)에 비해 상대적으로 더 큰 항균력을 지님을 알 수 있었다.

• The Plant Pathology Journal
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• 제36권1호
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• pp.54-66
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• 2020

This study was conducted to evaluate usefulness of numerical weather prediction data generated by the Unified Model (UM) for plant disease forecast. Using the UM06- and UM18-predicted weather data, which were released at 0600 and 1800 Universal Time Coordinated (UTC), respectively, by the Korea Meteorological Administration (KMA), disease forecast on bacterial grain rot (BGR) of rice was examined as compared with the model output based on the automated weather stations (AWS)-observed weather data. We analyzed performance of BGRcast based on the UM-predicted and the AWS-observed daily minimum temperature and average relative humidity in 2014 and 2015 from 29 locations representing major rice growing areas in Korea using regression analysis and two-way contingency table analysis. Temporal changes in weather conduciveness at two locations in 2014 were also analyzed with regard to daily weather conduciveness (C_i) and the 20-day and 7-day moving averages of C_i for the inoculum build-up phase (C_inc) prior to the panicle emergence of rice plants and the infection phase (C_inf) during the heading stage of rice plants, respectively. Based on C_inc and C_inf, we were able to obtain the same disease warnings at all locations regardless of the sources of weather data. In conclusion, the numerical weather prediction data from KMA could be reliable to apply as input data for plant disease forecast models. Weather prediction data would facilitate applications of weather-driven disease models for better disease management. Crop growers would have better options for disease control including both protective and curative measures when weather prediction data are used for disease warning.

• 한국작물학회:학술대회논문집
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• 한국작물학회 1999년도 추계 학술대회지
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• pp.80-101
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• 1999

Self-sufficiency ratio of food crops in Korea is estimated under $20{\%}$ in 2010 because total food consumption including feed will be increased. but food grain production will be decreased. It is necessary to maintain the optimum level of food self-sufficiency rate to secure national food demand/supply balance and non-trade and multiple function of agriculture in Korea. It will be possible to produce more food grains having the acceptable quality if the appropriate policy and cropping techniques are developed and practised in future. Breeding for high yielding varieties should be the first target to raise the production potential of food crops . Number of varieties developed during last 30 years is counted as 353 in food crops. New varieties developed in 1990s showed the higher yield potential and the improved agronomic characteristics compared with 1970s and 1980s varieties. But number of varieties planted on the farmer's field over $5{\%}$ of national planting area is less than one third of total varieties developed Breeding efforts to maintain planting area of main food crops should be focussed on consumer's demand and farmer's need. They are the best quality variety in each field of crop utilization, the newly designed variety adapting to changes of natural, rural and cropping environment, and the higher yielding variety. It is also needed to develop new quality crop varieties for inducing more consumption of crop grain produced in Korea for direct food or processing. Development of barley varieties for animal feed. high income soybean varieties, high quality wheat variety. and super yielding rice and barley varieties are also needed to keep or maximize national food production potential. In order to establish the appropriate cropping technique for domestic food security, the strong and continuous interest and financial support on crop breeding are required, and the inter-disciplinary and inter-institutionary researches should be strengthened for successful crop breeding.

• 한국작물학회지
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• 제51권4호
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• pp.335-339
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• 2006

The level of ${\beta}-glucan$ which is a major soluble dietary fiber found in the grain endosperm cell wall was highly variable among 25 barley genotypes grown at four locations including Suwon, Naju, Jinju, and Jeju. Statistically significant genotypic effects were observed for ${\beta}-glucan$ content at each or across growing sites (P<0.001). On average, 'Chalssalbori' showed the lowest percentage ${\beta}-glucan$ (4.04%) among genotypes in the grain, whereas 'Yonezawa Mochi' was highest in percentage ${\beta}-glucan$ (6.46%) compared to other genotypes. The significant difference between genotypes was approximately 1-2% across environments. The effects of location or interaction between locations and genotypes were not significant on the variation of ${\beta}-glucan$ contents. High ${\beta}-glucan$ content seemed to be greatly associated with such grain traits as waxiness and presence of husk except for 'Chalssalbori'. The waxy genotypes had a mean of 5.37% and values ranging from 5.28 to 5.47%, but normal genotypes had a mean of 4.78% and values ranging from 4.69 to 4.88% over environments. Hulless barley genotypes were also higher than hulled barley genotypes for the average ${\beta}-glucan$ content in both individual and over all environments. The difference between the hulled and hulless gene pools was on average of 0.37% with ranges from 0.19% to 0.56% at four environments. ${\beta}-glucan$ content measured from a mapping population of $F_5$-derived 107 lines derived from the cross between 'Yonezawa Mochi' and 'Neulssalbori' was not significantly associated with other agronomic traits except for 1,000-kernel weight at the '01 Suwon environment. Not too much information on the relationship of ${\beta}-glucan$ content to agronomic traits was available.

• 한국구조물진단유지관리공학회 논문집
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• 제15권5호
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• pp.209-217
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• 2011

최근 구조물들이 대형화됨으로써 보통 콘크리트를 사용할 경우 강도 및 내구성에 비하여 중량이 크다는 결점으로 인해 콘크리트 구조물의 설계 및 시공의 안정에 제약을 주게 된다. 이러한 결점을 개선하기 위해서는 자중이 작고 강도가 큰 경량콘크리트가 요구되나, 국내에서는 실용화를 위한 연구가 아직 미비한 실정에 있다. 일반적으로 고온에서 소성시켜 제조된 인공골재는 골재가 팽창되어 내부에 무수한 기포를 가지게 된다. 따라서 골재의 크기에 따라 이들의 기포가 경량콘크리트 비중과 강도에 미치는 영향 연구가 필요하다. 본 연구에서는 국내에서 개발된 화력발전소 폐기물과 점토를 고온에서 소성, 팽창시켜 만든 인공경량골재의 입도별 배합설계를 실시하고 실험을 통하여 경량콘크리트의 비중 및 강도변화를 비교 고찰했다. 또한 경량콘크리트의 고강도 발현을 위한 인공경량골재의 최적 입도비를 제안하였다.

• 한국수산과학회지
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• 제44권6호
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• pp.772-784
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• 2011

We measured grain size, organic matter, and metallic elements (Fe, Cu, Pb, Zn, Cd, Cr, Mn, Hg, and As) in intertidal sediments collected from six islands in the western part of Jellanam Province in order to evaluate heavy metal contamination in the tidal flat sediments of coastal islands. The evaluation of metal contamination was carried out using geochemical assessment techniques such as sediment quality guidelines (SQGs), enrichment factor (EF), and geoaccumulation index ($I_{geo}$). Surface sediments were classified into four sedimentary facies: sand, gravelly muddy sand, slightly gravelly mud, and silt. The concentrations of heavy metals in intertidal sediments from Jaeun, Amtae, Biguem, and Docho islands showed good positive correlations with mean grain size and ignition loss, indicating that the concentrations of metallic elements in these sediments were dependent on grain size and the organic matter content. The concentrations of heavy metals in sediments from almost all of the stations were lower than two criterion values proposed by the National Oceanic and Atmospheric Administration (NOAA) in the United States. Based on the EF and $I_{geo}$ results, surface sediments were a little polluted for Cr and were moderately polluted for As. Our results suggest that more intensive studies are necessary in the future in order to determine the major source of As in intertidal sediment and to evaluate the As pollution level in macrobenthos.

• 한국정보전자통신기술학회논문지
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• 제11권2호
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• pp.161-168
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• 2018

본 논문은 곡물의 수확후 이력관리를 위하여 미곡종합처리장(RPC, Rice processing complex)에서 곡물의 반입, 건조, 저장 및 가공공정에서의 변화하는 중량 및 함수율 정보를 실시간으로 측정하고 모니터링이 가능한 IT기반의 이력관리시스템을 개발하였다. 곡물의 반입, 건조, 저장 및 가공 등 수확후 처리공정에서 반입 및 배출과정에서 중량 및 함수율 정보를 실시간으로 수집하고 이를 기반으로 수율 및 감모와 같은 품질정보를 DB sever에 저장하였다. 이 때의 Lot No를 생성하여 품질 및 이력정보를 연계하여 이력관리가 가능한 시스템을 구축할 수 있도록 설계하였다. 또한, MMI(Man Machine Interface)기반의 자동제어시스템과 자동수율 및 재고관리 시스템(YICS)과 TCP/IP통신을 이용하여 곡물을 대상으로 한 IT 기반의 이력관리시스템을 구축하였으며, 미곡종합처리장에서 시뮬레이션을 통해 검증을 수행하였다.

• 대한금속재료학회지
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• 제50권1호
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• pp.52-58
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• 2012

Hydrogen-delayed fracture (HDF) was analyzed from the deposited weld metals of 600-MPa and 800-MPa flux-cored arc (FCA) welding wires, and then from the diffusible hydrogen behavior of the weld zone. Two types of deposited weld metal, that is, rutile weld metal and alkali weld metal, were used for each strength level. Constant loading test (CLT) and thermal desorption spectrometry (TDS) analysis were conducted on the hydrogen pre-charged specimens electrochemically for 72 h. The effects of microstructures such as acicular ferrite, grain-boundary ferrite, and low-temperature-transformation phase on the time-to-failure and amount of diffusible hydrogen were analyzed. The fracture time for hydrogen-purged specimens in the constant loading tests decreased as the grain size of acicular ferrite decreased. The major trapping site for diffusible hydrogen was the grain boundary, as determined by calculating the activation energies for hydrogen detrapping. As the strength was increased and alkali weld metal was used, the resistance to HDF decreased.

• 한국지형학회지
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• 제18권4호
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• pp.203-212
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• 2011

감조하천이 발달한 경기도 파주시 탄현면 일대의 공릉천 감조구간을 연구지역으로 하여 표층퇴적물의 공간적 분포 특성을 조사하였다. 연구 결과는 다음과 같다. 첫째, 공릉천 감조구간의 표층퇴적물은 주로 실트로 구성되어 있다. 둘째, 종단축의 경우 겨울과 여름 모두 감조구간의 하류보다 상류에서 평균입도가 세립해지는 경향이 나타났으며, 여름이 겨울보다 평균입도가 작고 분급이 양호한 것으로 나타났다. 감조구간 종단축의 입도 분포를 볼 때 부유물질이 퇴적되는 데에는 조류의 작용, 특히 밀물의 영향을 많이 받는 것으로 보이며 이러한 경향은 겨울에 더 우세한 것으로 판단된다. 셋째, 횡단축의 경우 하도로부터 거리가 멀어질수록 평균입도가 세립해지는 경향이 나타났다. 넷째, 갑문과 같은 인공 시설 역시 유속을 정체시킴으로써 입도 분포에 영향을 미친다고 판단된다.