Particle size reduction is an important step in many technological operations. The process itself is defined as the mechanical breakdown of solids into smaller particles to increase the surface area and induce defects in solids, which are needed for subsequent operations such as chemical reactions. To fabricate nano-sized particles, several tens to hundreds of micron size ceramic beads, formed through high energy milling process, are required. To minimize the contamination effects during highenergy milling, the mechanical properties of zirconia beads are very important. Generally, the mechanical properties of Y2O3 stabilized tetragonal zirconia beads are closely related to the mechanism of phase change from tetragonal to monoclinic phase via external mechanical forces. Therefore, Y2O3 distribution in the sintered zirconia beads must also be closely related with the mechanical properties of the beads. In this work, commercially available 100μm-size beads are analyzed from the point of view of microstructure, composition homogeneity (especially for Y2O3), mechanical properties, and attrition rate.

Two climate change scenarios, the RCP (Representative Concentration Pathways) 4.5 and the RCP 8.5 in the fifth Assessment Report (AR5) by Intergovernmental Panel on Climate Change (IPCC), were applied in the Yocheon basin area using the SWAT (Soil and Water Assessment Tool) model to estimate changes in flow rates and pollutant loadings in the future. Field stream flow rate data in Songdong station and water quality data in Yocheon-1 station between 2013~2015 were used for model calibration. While R2 value of flow rate calibration was 0.85 and R2 value of water qualities were in the 0.12~0.43 range. The total study period was divided into 4 sub periods as 2030s (2016~2040), 2050s (2041~2070) and 2080s (2071~2100). The predicted results of flow rates and water quality concentrations were compared with results in calibrated periods, 2015s (2013~2015). In both RCP scenarios, flow rate and TSS (Total Suspended Solid) loadings were estimated to be in increasing trend while TN (Total Nitrogen) and TP (Total Phosphorus) loadings showed decreasing patterns. Also, flow rates and pollutant loadings showed larger differences between the maximum and the minimum values in RCP 4.5 than RCP 8.5 scenarios indicating more severe effect of drought and flood, respectively. Dependent on simulation period and rainfall periods in a year, flow rate, TSS, TN and TP showed different trends in each scenario. This emphasizes importance of considerations on time and space when analyzing climate change impacts of each variable under various scenarios.

The purpose of this study is to implement through the utilization of geographical information that was currently constructed in the development of the radon map creation methodology. In addition, we suggested a model for forecasting radon gas in soil based on the mechanism of radon exhalation from soil. To provide basic data for radon mapping in Korea, we compared the results obtained using the proposed model with the results of a field survey. Based on the comparison, we discussed the feasibility of the proposed model. The soil radon exhalation rate prediction model was built on the first order prediction model in the steady-state based on the law of conversion of mass. To verify the model by comparing the predicted value with a field survey, a grid of 7.5 × 6.3 cm was created at a 1:500,000 map of Korea, and the intersection point of the grid was selected as measurement site. The results showed a low error rate when compared with the previous studies, and it is expected that the model proposed in this study and the currently constructed geogenic information database can be used in combination to map the soil radon gas in Korea.

This study suggested a new real-time traffic signal operation algorithm using combined data of travel time and occupancy rate. This study applied the travel time data to traffic signal control system, and developed the signal operation algorithm based on saturation degree that was calculated using the travel time data. This algorithm calculates a queue length using a delay model, and converts the queue length to the saturation degree. Moreover, it calculates signal timing variables using this combined saturation degree. This study conducted a microscopic simulation for effectiveness evaluation. We checked that the average intersection delay decreased by up to 27 percent. Moreover, we checked that this signal operation algorithm could respond to a traffic condition of oversaturation and loop detector error effectively and usefully. In korea, sectional traffic detection systems are being installed in various ITS projects, such as Advanced Transportation Management System(ATMS) and Urban Transportation Information System(UTIS). This study has important significance in the sense that it is new methodology to accept the sectional detection system in traffic signal control system.

The aim of this research was to determine the effect of drying conditions (drying air temperature and drying time) on drying rate, effective diffusivity, and activation energy during hot-air drying of jujube slices. Jujube slices were dried in a laboratory scale convective hot-air dryer at an air temperature in a range of 50-70℃ with an air flow of 0.66 m/s. Sliced jujubes did not exhibit a constant-rate drying period and all the drying operations are seen to occur in the falling rate period. At the beginning of drying process, drying rate was very high, and drying rate continued to decrease as moisture content approached to equilibrium moisture content. It is apparent that drying rate decreases continuously with decreasing moisture content or increasing drying time. It is also noted that the drying rate increased with the increase in drying air temperature. The drying rate was more for jujube slices dried at higher temperature than the ones dried at lower temperature for the same average moisture content of the sample. Consequently, the drying time decreased at a higher drying air temperature condition. Moisture transfer from jujube slices was described by applying the Fick's diffusion model and the effective diffusivity changed between 1.354×10-10 and 2.787×10-10 m2/s within the given temperature range. Effective diffusivity increased linearly with increasing temperature. An Arrhenius relation with activation energy values of 33.22 kJ/mol for jujube slices by hot-air drying expressed the effect of temperature on the diffusivity.

작물의 생산량은 광합성과 밀접한 관계가 있으며, 광합성 속도는 다양한 환경 요인에 의해 변화한다. 광합성 속도는 작물의 생육 상태나 생육 속도를 판단하는 지표로 사용되며, 작물 재배 시설을 구축하는 데 고 려해야 하는 중요한 요인이다. 이 연구의 목적은 광도, CO2 농도 및 생육 단계에 의해 변화하는 로메인 상추 의 군락 광합성 속도 모델을 개발하는 것이다. 군락 광합성 속도는 정식 후 5, 10, 15, 20 일차에서 5단계의 CO2 농도(600-2,200μmol·mol-1)와 5단계의 광조건(60-340μmol·m-2·s-1)이 처리된 3개의 밀폐 아크릴 챔버(1.0 × 0.8 × 0.5m) 내에서 측정하였다. 먼저 세 가지 환경 요인을 사용하는 식들을 곱하여 만든 단순곱모델을 구성 하였다. 이와 동시에 생육 시기에 따라 변화하는 광화학 이용효율과 카르복실화 컨덕턴스, 호흡에 의한 이산화탄소 발생 속도를 포함하는 수정 직각쌍곡선 모델을 구성하여 단순곱 모델과 비교하였다. 검증 결과, 단순곱 모델의 R2는 0.923이었으며, 수정 직각쌍곡선 모델의 R2는 0.941을 나타내었다. 따라서 수정 직각쌍곡선 모델 이 광도, CO2 농도, 생육 단계의 3 변수에 따른 군락 광합성 속도를 표현하는 데 더욱 적합한 것으로 판단하 였다. 본 연구에서 개발된 군락 광합성 모델은 식물공장에서 상추 재배를 위해 생육 단계별로 설정해야 할 최 적의 광도와 CO2 농도를 결정하는데 도움이 될 것으로 생각된다.

본 연구는 하절기 ‘매향’ 딸기 자묘의 삽목 번식에 적 절한 관수 방법을 구명하기 위해 수행되었다. 딸기 자묘의 삽수는 24구 딸기 전용 포트(24구, 60 × 34 × 10cm) 에 상업용 혼합 상토(Tosilee)를 이용하여 삽목하고, 반 밀폐형 소형비닐터널에 위치시켰다. 각각의 반 밀폐형 소형터널의 처리는 다음과 같이 처리했다; 대조구(무처 리), 두상관수(하루 두 번), 매트관수(하루 두 번), 그리 고 안개관수(8:00시부터 18:00시까지 30분 온/오프 설정). 딸기 자묘는 반 밀폐형 소형터널 내에서 8일 동안 발근을 하였고, 그 이후 플라스틱 필름을 제거 하였다. 삽목 후 61일째에 초장, 근장, 1차 근수, 엽병장, 엽장, 엽폭, 크라운 직경, 엽록소 값, 엽면적, 지상부와 지하부의 생 체중 및 건물중을 측정하였다. 터널 내의 하루 평균 상 대습도는 각각 안개관수, 두상관수, 매트관수, 대조구순 으로 72.5, 56.3, 45.8, 그리고 29%를 나타냈다. 그러나 공기온도는 모든 처리에서 유사하였다. 딸기 자묘의 4일 째와 8일째 발근율은 두상관수와 안개관수 처리에서 유 의적으로 높았다. 초장, 엽병장, 크라운 직경, 엽면적은 두상관수와 안개관수 처리에서 높은 값을 나타냈다. 게다가 지상부의 생체중 및 건물중은 다른 처리에 비해 두상관수와 안개관수 처리에서 무거웠다. 지하부의 건물 중은 안개관수 처리에서 유의적으로 무거웠다. 하지만 근장, 1차 근수, 엽록소 값, 지하부의 생체중은 모든 처 리구에서 유의적인 차이를 나타내지 않았다. 결과적으로, ‘매향’ 딸기의 삽목 번식 시 생육과 발근율은 두상관수 와 안개관수 처리에서 가장 효과적인 것으로 나타났다.

PURPOSES : This purpose of this study is to analyze the effect to autogenous shrinkage of the top-layer material of a two-lift concrete pavement mixing both silica fume and polymer powder. METHODS: The bottom-layer of a two-lift concrete pavement was paved with original portland cement (OPC) with a 20~23 cm thickness. Additionally, the top-layer which is directly exposed to the environment and vehicles was paved with a high-performance concrete (HPC) with a 7~10 cm thickness. These types of pavements can achieve a long service life by reducing joint damage and increasing the abrasion and scaling resistance. In order to integrate the different bottom and top layer materials, autogenous shrinkage tests were performed in this study according to the mixing ratio of silica fume and polymer powder, which are the admixture of the top-layer material. RESULTS: Autogenous shrinkage decreased when polymer powder was used in the mix. Contrary to this, autogenous shrinkage tended to rise with increasing silica fume content. However, the effects were not significant when small amounts of polymer powder were used (3% and 11%). CONCLUSIONS : The durability and compressive strength increase when silica fume is used in the mix. The flexural strength considerably increases and autogenous shrinkage of concrete decreases when polymer powder is used in the mix. As seen from above, the proper use of these materials improves not only durability, but also autogenous shrinkage, leading to better shrinkage crack control in the concrete.

본 연구에서는 스트레스에 대한 심리 반응 요인과 인지 스트레스원에 의해 유발된 심박변이도의 변화와의 관계를 확인하고자 하였다. 33명의 실험참여자는 지난 2주 동안 경험한 스트레스에 대하여 정신적 신체적 증상들을 스트레스 반응 척도 상에 평가하였다. 또한 실험참여자가 인지 스트레스 과제를 수행하는 동안 심전도 신호가 기록되었다. 심박변이도 지표로서, R-R간격의 표준편차(SDNN), 연속한 R-R 간격 차이 값의 평균제곱근(RMSSD)과 심박변이도의 저주파 성분(LF)과 고주파 성분(HF)의 비율이 추출되었다. 스트레스 반응은 회복기 동안의 평균에서 기저선의 평균을 뺀 차이값으로 분석에 사용되었다. 분석 결과, 스트레스 요인과 심박변이도 지표들과의 유의한 정적 상관을 보였다. 특히 스트레스에 대한 공격 반응의 증가는 모든 심박변이도 지표의 증가와 연관이 있었다. 모든 심박변이도 지표의 증가는 자율신경계가 동시에 활성화됨을 의미한다. 즉, 공격 반응의 증가는 교감 및 부교감신경계의 활성도의 증가와 관련이 있다. 또한 긴장, 우울, 피로와 좌절은 RMSSD와의 정적 상관이 있었다. RMSSD의 증가는 부교감신경계 활성의 증가를 의미하는 것으로, 긴장, 우울, 피로, 좌절의 증가와 부교감 신경의 활성도의 증가가 연관이 있었다. 이러한 자율신경의 공동 활성화는 주의 집중을 요하는 인지 스트레스원에 대한 통합된 반응으로 여겨진다.

In this study, the loading rates (or emission rate) and concentrations of air pollutants (ammonia, hydrogen sulfide, carbon dioxide, methane, nitrous oxide, and particulate matter (PM2.5, PM10 and TSP)) emitted from a naturally ventilated dairy facility were analyzed and compared to enable a better understanding that are in close proximity to each other, air pollution status. In general, the pollution patterns should be similar in measurement sites that are in close proximity to each other, and this hypothesis was fundamental to our approach in this study. For the comparison in nearby different sites, monitoring points were located at inside (source site) and outside the dairy building (ambient site), and concentrations and wind velocity were simultaneously monitored in real time. The patterns of PM2.5 emission rate and loading rate were similar in the source site and the ambient site which was consist with the hypothesis, while the PM2.5 mass concentration were not similar in both sites. As well as PM2.5, the emission rates (source site) of gaseous carbon dioxide (CO2) and nitrous oxide (N2O) were highly correlated to their loading rates (ambient site), while the concentrations of CO2 and N2O were not similar. Therefore, wind velocity, which is included in the emission or loading rate, should be simultaneously monitored with the concentration at the same measurement points for better understanding of the air pollution status.

본 연구는 콩 콤바인 수확 시 수확장애와 종실의 품위를 떨어뜨리는 잎과 줄기의 노화 지연에 관한 연구로 2015~2016년도 국립식량과학원 남부작물부(경남 밀양시 소재)의 시험포장에서 수행하였다. 시험품종은 대원콩과 풍산나물콩을 사용하였으며, 6월 9일에 고휴 2열로 휴폭 110 cm, 주간거리 40 cm, 1주 2본 재배하였고, 콩 꼬투리를 0~50%범위에 수준별로 제거하여 성숙기 생육특성과 잎과 줄기의 건물중에 대해서 조사하였다. 주요결과를 요약하면 다음과 같다. 1. 대원콩과 풍산나물콩 모두 종실비대시 콩 꼬투리 제거가 생육특성에 영향을 미치지는 않았지만, 제거 비율이 높아질수록 성숙기가 지연되었다. 2. 콩 꼬투리 제거 비율이 높아짐에 따라 종실 무게도 증가하였는데 꼬투리의 제거비율이 대원콩은 20%, 풍산나물콩은 30% 이상일 경우에는 차이가 없었다. 3. 꼬투리 제거비율이 높아질수록 잎과 줄기의 건물중이 증가하였는데, 이는 종자에 축적되어야 할 잉여 동화 산물이 잎과 줄기에 축적된 결과로 보여진다. 4. Sink/source 감소폭은 대원콩 20% 제거 시 0.18, 풍산나물콩 30% 제거 시 0.42로 이전 처리구에 비해 크게 감소하였기 때문에 잎과 줄기의 성숙이 불리할 것으로 판단된다.

본 연구에서는 센서의 표면적 변화에 따른 입체적 호흡수 센서의 센싱 방식을 제안하고, 직물 기반의 입체적 호흡수 센서의 성능 평가 및 의복에 적용할 수 있는 디자인 방향성을 탐색하고자 한다. 이를 위해 입체적 구조의 차이에 따라 2가지 유형의 입체적 호흡수 센서를 제작하고 더미와 인체 대상으로 연구를 실시하였다. 연구Ⅰ은 더미 대상 실험으로 센서의 유형 및 호흡 속도의 연구변인에 의해 입체적 호흡수 센서의 측정 가능성을 탐색하였다. 연구Ⅱ는 7명의 20대 남성을 대상 실험으로 연구Ⅰ의 연구변인 이외에 3개의 측정 위치별 적합한 유형의 센서를 제안하였다. 입체적 호흡수 센서의 정확도, 재현성, 신뢰도를 평가하기 위해, 의료기기 분야의 대표적 웨어러블 호흡수 센서인 BIOPAC을 사용하여 입체적 호흡수 센서와 동시에 호흡수를 측정하였다. 이상의 연구 결과를 통해 더미 대상으로 입체적 호흡수 센서의 측정 가능성을 탐색하였으며, 인체 대상으로 호흡수를 측정하여 측정 위치별 적합한 유형의 센서를 제안하였다.

The aim of the study was to set up assessment indicators for early elimination of horses that are not trainable or low efficient for training by comparing difference of behavioral response and heart rate on stimulation of desensitization training in horses. The animals used in this study were 8 untrained cross-bred horses (Thoroughbred and Jeju-horse) in Jeju island. Changes of heart rates and behavioral response of each horses were compared before and after desensitization training using a plastic bag on its tip. The result showed that the horses with their severe behavioral response were also high in heart rate during early stage of desensitization training, and the increased heart rates were recovered back to the base level according to the process of the training. The horses that quickly recovered in heart rate also showed same tendency in behavioral response. The horses that their recovery in heart rate and behavioral response in early stage of the desensitization training were late, showed insufficient results of the additional desensitization training. We conclude that assessment of heart rate and behavioral response in the early stage of desensitization training could be used as indicators to predict the effectiveness of desensitization or other kinds of training in horses.

This study was conducted to explore the effects of seeding rate of a seed mixture on grassland productivity and botanical composition. Seeding rates were composed of four different treatments varying by the amount of seed: T1, 50% decrease in seeding rate from standard; T2, standard seeding rate; T3, 50% increase in seeding rate from standard; and T4, 100% increase in seeding rate from standard. In 2016, seasonal changes in grass botanical composition revealed T2, T3, and T4 in portion of grass ratio were the highest with a range of 87–100%, whereas T1 was the lowest of all treatments. In 2017, the botanical composition in T1 showed that the grass ratio in of the first cutting was 91%, but in the fourth cutting its ratio decreased by 75%. The results from both years were combined for each treatment, T4 (11,435 kg ha-1) and T3 (11,162 kg ha-1) demonstrated the highest dry matter yield of the treatments (T1: 8,196 kg ha-1; T2: 9,521 kg ha-1) (p＜0.05). As a result, a 50–100% increase in the seeding rate from the standard demonstrated the best grassland yield and botanical composition.

The objective of this study was to investigate the effects of freeze dried placenta supplementation on reproductive performance, colostrum and plasma biochemical composition in pregnant sows. Eleven Landrace × Large white sows were fed with corn-soybean meal diets supplemented with or without 1% freeze dried placenta powder from 10 days before their expected farrowing dates until 10 days postpartum. The colostrum protein content was significantly higher(P=0.043) in the treatment group than in the control group. Compared to the control group, the immunoglobulin G(IgG) concentration in the colostrum was significantly higher(P=0.004) in the treatment. In day 25 piglets plasma, the IgG concentration was higher(P=0.184) in the treatment than the control. The mortality rate was lower(P=0.102), and the piglet weight gain was higher(P=0.35) in the treated group. Overall, the treatment group showed greater levels of protein and IgG concentration in the colostrum, when compared to control group. Therefore, the freeze dried placenta supplementation on pregnant sows can enhance its colostrum composition, hence decrease the mortality and increase the growth rate of piglets.