말채나무공깍지벌레의 계절적 발육을 2019년 6월 4일(약충) 부터 2020년 6월 25일까지(1세대 약충) 경상남도 사천시 소재의 블루베리 과 원에서 관찰하였다. 본 충의 발육을 연구하기 위해서 2018년 눈에서 발아한 5개 이상의 잔가지를 1주 간격으로 농가에서 채취하였다. 깍지벌레의 발육은 실체현미경 하에서 조사하였고 화학적 방제는 시중에서 이용할 수 있는 3종의 살충제로 블루베리 과원에서 수행하였다. 발육기간과 유효적산온도(Centigrade Degree-Days accumulation, DDC)에 대한 결과는 다음과 같다. 산란기간(최성기): 2020년 5월 12 -26일(DDC, 110.0-188.5(173.6)); 부화기간(최성기): 2020년 6월 9 - 23(19)일)(DDC, 325.2-480.8(435.6); 난기간: 26 일; 월동성충으로부터 약충의 신엽으로 이동: 2020년 6월 16-25 일(DDC, 410,5 - 500.4); 성충으로 발육하기 위한 잎에서 잔가지로 이동(최성기): 2020년 2월 4 -18(8)일. 성충 한 마리 당 산란수(범위): 956.8 ± 73.4 (13 - 3497); 알의 크기(mm): 0.29 ± 0.020(L), 0.15 ± 0.013(W); 부화약충의 크기: 0.35 ± 0.018(L), 0.18 ± 0.007(W), 0.09 ± 0.007(눈 간격); 성충크기: 4.30 ± 0.893(L), 2.64 ± 0.520(W). 월동성충으로부터 부화한 약충은 신초의 잎 뒷면에서 다음해 2월 초순 잎이 떨어질 때까지 약 95%가 발견되었다. 이들은 2령충으로 월동하고 1년에 한 세대를 경과하였다. 기어다니는 1령충을 방제 하기 위하여 3종의 살충제를 7월 16일과 30일에 거북밀깍지벌레에 등록된 농도로 처리하였다. 아세타미프리드수화제가 1회 처리 21일 후에 96.9%의 사충율을 나타내었다.

Central odontogenic fibroma (COF) is an uncommon slow growing benign neoplasm that is derived from the mesenchymal tissue. Differential diagnoses include fibrous dysplasia, calcifying odontogenic cyst, and central ossifying fibroma. Clinically, the lesion shows expansion of cortical bone. Radiologically, unilocular or multilocular lesion with well-defined borders is found. Histologically, fibroblastic tissues with bundle of collagens including inactive odontogenic epithelium can be observed. In this case report, a 45-year-old male with central odontogenic fibroma of the maxilla is examined. The lesion was surgically removed without any postoperative complications. In order to diagnose the disease properly, histopathologic analysis was performed.

이 연구의 목적은 8주간의 플라이오메트릭 훈련이 대학 태권도 시범단의 순발력, 동적 평형성 및 관절 위치감각에 미치는 영향을 분석하고자 하였다. 태권도 시범 전공 대학생 20명을 훈련군 10명, 통제군 10명으로 분류한 후 운동군은 주 3회, 60분, 8주간 플라이오메트릭 훈련을 하였다. 측정 변인은 제자 리높이뛰기, 제자리멀리뛰기, 배근력, 동적 평형성 및 관절 위치감각으로 사전 사후 측정하였다. 연구 결과, 제자리높이뛰기와 멀리뛰기 및 배근력에서 유의한 운동의 효과가 있었다(p<.05). 동적 평형성은 후방 바깥 쪽과(p<.01) 후방 안쪽에서(p<.05) 유의한 운동의 효과가 있었다. 관절 위치감각은 왼발 15°와(p<.01) 45°에서는(p<.05) 운동군에서 유의한 효과가 있었다. 이상의 결과 8주간의 플라이오메트릭 훈련은 태권도 시범선수의 순발력과 동적 평형성 및 관절 위치감각에 긍정적인 영향을 미치는 것으로 나타났다.

In this study, a nanocrystalline FeNiCrMoMnSiC alloy was fabricated, and its austenite stability, microstructure, and mechanical properties were investigated. A sintered FeNiCrMoMnSiC alloy sample with nanosized crystal was obtained by high-energy ball milling and spark plasma sintering. The sintering behavior was investigated by measuring the displacement according to the temperature of the sintered body. Through microstructural analysis, it was confirmed that a compact sintered body with few pores was produced, and cementite was formed. The stability of the austenite phase in the sintered samples was evaluated by X-ray diffraction analysis and electron backscatter diffraction. Results revealed a measured value of 51.6% and that the alloy had seven times more austenite stability than AISI 4340 wrought steel. The hardness of the sintered alloy was 60.4 HRC, which was up to 2.4 times higher than that of wrought steel.

The effect of sintering conditions on the austenite stability and strain-induced martensitic transformation of nanocrystalline FeCrC alloy is investigated. Nanocrystalline FeCrC alloys are successfully fabricated by spark plasma sintering with an extremely short densification time to obtain the theoretical density value and prevent grain growth. The nanocrystallite size in the sintered alloys contributes to increased austenite stability. The phase fraction of the FeCrC sintered alloy before and after deformation according to the sintering holding time is measured using X-ray diffraction and electron backscatter diffraction analysis. During compressive deformation, the volume fraction of strain-induced martensite resulting from austenite decomposition is increased. The transformation kinetics of the strain-induced martensite is evaluated using an empirical equation considering the austenite stability factor. The hardness of the S0W and S10W samples increase to 62.4-67.5 and 58.9-63.4 HRC before and after deformation. The hardness results confirmed that the mechanical properties are improved owing to the effects of grain refinement and strain-induced martensitic transformation in the nanocrystalline FeCrC alloy.

We fabricate the non-equiatomic high-entropy alloy (NE-HEA) Fe49.5Mn30Co10Cr10C0.5 (at.%) using spark plasma sintering under various sintering conditions. Each elemental pure powder is milled by high-energy ball milling to prepare NE-HEA powder. The microstructure and mechanical properties of the sintered samples are investigated using various methods. We use the X-ray diffraction (XRD) method to investigate the microstructural characteristics. Quantitative phase analysis is performed by direct comparison of the XRD results. A tensile test is used to compare the mechanical properties of small samples. Next, electron backscatter diffraction analysis is performed to analyze the phase fraction, and the results are compared to those of XRD analysis. By combining different sintering durations and temperature conditions, we attempt to identify suitable spark plasma sintering conditions that yield mechanical properties comparable with previously reported values. The samples sintered at 900 and 1000oC with no holding time have a tensile strength of over 1000 MPa.

This study was undertaken to investigate whether HEPA filter-equipped air purifiers can remove aerosolized virus, whether the removed virus can re-scatter through the filter, and how long the removed virus keeps its infectivity in the filter. For this investigation, six HEPA filter-equipped air purifiers produced by different companies were tested against PhiX174 and MS2 phages aerosolized by nebulizers. For viral detection from the air, LB agar plates covered with Escherichia coli hosts and an Andersen air sampler were used, and from the surface, the swab method was used. Both the aerosolized PhiX174 and MS2 viruses absorbed by the HEPA filters in the air purifiers were not detected from the air through filters or the surface of the outlet of the air purifiers. During the operation of the air purifiers at medium mode, the infectious viral concentration of these viruses in the HEPA filters decreased to 0%~12.3% as the time period passed. These results regarding infectious viral concentration differences were assumed to be due to the different wind speed and air volume among the six air purifiers. Based on observations over 5 days, the infectious viral concentration of the PhiX174 phage was 8,600 times lower when the air purifier was operated than when it was not operated. Overall, our results demonstrate that HEPA filter-equipped air purifiers can efficiently remove the two aerosolized viruses and the removed viruses in the HEPA filter could not re-spread and maintain their infectivity.

High-entropy alloys have excellent mechanical properties under extreme environments, rendering them promising candidates for next-generation structural materials. It is desirable to develop non-equiatomic high-entropy alloys that do not require many expensive or heavy elements, contrary to the requirements of typical high-entropy alloys. In this study, a non-equiatomic high-entropy alloy powder Fe49.5Mn30Co10Cr10C0.5 (at.%) is prepared by high energy ball milling and fabricated by spark plasma sintering. By combining different ball milling times and ball-topowder ratios, we attempt to find a proper mechanical alloying condition to achieve improved mechanical properties. The milled powder and sintered specimens are examined using X-ray diffraction to investigate the progress of mechanical alloying and microstructural changes. A miniature tensile specimen after sintering is used to investigate the mechanical properties. Furthermore, quantitative analysis of the microstructure is performed using electron backscatter diffraction.

화상병균(Erwinia amylovora)에 의해 발생하는 과수 화상병은 주로 사과, 배 등의 장미과 식물에서 발병한다. 과수 화상병은 국내에서 금지 병원균으로 지정되어 있으며, 2015년 경기도 안성의 배과수원에서 최초 발견되었다. 그러나, 현재까지 근본적인 방제약제가 없는 상황으로 발생지는 매몰이 최선의 방법으로 여겨진다. 따라서 본 연구에서는 2019년을 기준으로 충북지역의 과수 화상병 발생 원인 분석을 통하여 발생 경로 차단을 위한 역학조사를 실시하였다. 1. 충주시 등 3개 시군의 전체 221농가 141ha에서 과수 화상병이 발생하였으며, 세부적인 연도별 발생현황은 2015년(2농가 1ha), 2018년(74농가 51.5ha), 2019년(145농가 88.9ha) 로 나타났다. 2. 과수 화상병의 발생시기는 주로 5월부터 8월 사이로 나타났으며, 특히 6월(73.8%)이 가장 많이 발생하였으며, 7월 (17.2%), 5월(7.6%), 8월(1.4%)순으로 나타났다. 3. 과수 화상병 발생 의심 신고 후 확진 매몰까지 소요기간은 11.9일이었고, 발생에서 매몰까지의 기간은 최단 5일에서 최장 19일로 조사되었다. 4. 병원균의 최초 발생지로부터의 확산 거리는 평균 21 km로 나타났으며 가장 먼거리는 음성군 비산면으로 34 km였다.

This paper presents a real-time, false-pick filter based on deep learning to reduce false alarms of an onsite Earthquake Early Warning (EEW) system. Most onsite EEW systems use P-wave to predict S-wave. Therefore, it is essential to properly distinguish P-waves from noises or other seismic phases to avoid false alarms. To reduce false-picks causing false alarms, this study made the EEWNet Part 1 'False-Pick Filter' model based on Convolutional Neural Network (CNN). Specifically, it modified the Pick_FP (Lomax et al.) to generate input data such as the amplitude, velocity, and displacement of three components from 2 seconds ahead and 2 seconds after the P-wave arrival following one-second time steps. This model extracts log-mel power spectrum features from this input data, then classifies P-waves and others using these features. The dataset consisted of 3,189,583 samples: 81,394 samples from event data (727 events in the Korean Peninsula, 103 teleseismic events, and 1,734 events in Taiwan) and 3,108,189 samples from continuous data (recorded by seismic stations in South Korea for 27 months from 2018 to 2020). This model was trained with 1,826,357 samples through balancing, then tested on continuous data samples of the year 2019, filtering more than 99% of strong false-picks that could trigger false alarms. This model was developed as a module for USGS Earthworm and is written in C language to operate with minimal computing resources.

This study was conducted to investigate the growth characteristics of the shoot and roots and to analyse the morphological characteristics of roots of waterlogging resistant and susceptible maize inbred lines. Six maize inbred lines were treated with waterlogging for 10 days at V3, and the degree of leaf senescence was evaluated for waterlogging resistance. As a result of waterlogging resistance evaluation, KS85 was the most damaged inbred line with 3.33 senescence leaves and 5.54 degree, and KS141 was the least damaged inbred line with 1.33 senescence leaves and 3 degree. At 20 days after treatment, the effect of waterlogging stress on the shoot dry matter accumulation of KS85 and KS141 were decreased by 86.1% and 77.0%, respectively, compared to the control. Similarly, root dry matter accumulation of KS85 and KS141 were decreased by 77.6% and 65.0%. As a result of SEM photographs of the nodal roots of the two maize inbred lines, the thickness of cortex of KS141 was thicker than that of KS85, and the distortion of the cortex was observed in KS85 at 20 days after waterlogging. It was concluded that the thickness of cortex was related to maize waterlogging resistance.

PURPOSES : This study aimed to examine the relationship between discomfort glare and different types of lighting, including low-mounted lighting and conventional pole lighting. Although roadway lighting has been widely acknowledged as a countermeasure for nighttime traffic safety, discomfort glare, which is incidentally derived from lighting, is one of the key elements to overcome. METHODS : We selected the Unified Glare Rating (UGR), defined as a globally accepted lighting standard, as a measure of the effect of discomfort glare. Artificial rain and fog conditions were reproduced at the Center of Road Weather Proving Ground (CRPG). RESULTS : As a result, we found that the UGR of low-mounted lighting is reduced by 57.96% compared to pole lighting under rainy conditions, and by 39.12% in the case of fog conditions. CONCLUSIONS : It is proposed that discomfort glare was significantly reduced in the case of low-mounted lighting compared to pole lighting under both rain and fog conditions. Discomfort glare hinders the visual performance of drivers, so it may be related to delayed reaction time and inappropriate driving behavior. Therefore, low-mounted lighting is strongly recommended on road sections that have a high frequency of traffic accidents and adverse weather patterns.

PURPOSES : This study aimed to examine the effect of fog on the optical properties of taillights and the relationship between luminous intensity and the visibility distance of taillights on the road. METHODS : Changes in luminous intensity were measured using a light meter. Participants subjectively evaluated visibility distance. The artificial fog was reproduced using weather-generating facilities at the Center of Road Weather Proving Ground (CRPG). RESULTS : As expected, the average luminous intensity under intermediate fog conditions was reduced to 72% compared to normal weather conditions and 44% under heavy fog conditions in the case of the tail lamp-only lit condition. In the case of the tail lamp and brake lamp lit condition, the average luminous intensity was reduced to 76% under heavy fog conditions and 55% under intermediate fog conditions compared to normal dry conditions. In addition, the average visibility distance was reduced by 41% when fog conditions changed from intermediate to heavy in the case of the tail lamp-only lit condition and 39% in the case of the tail lamp and brake lamp lit conditions. Changes in visibility distance corresponding to the gradual change in luminous change were evaluated by participants, and the linearly regressed equations for the relationship between the intensity levels and the visibility distance were derived and examined for their meaning in terms of road traffic safety concerning stopping sight distance. CONCLUSIONS : Luminous intensities were suggested, given the design speeds, to satisfy the minimum stopping distances. In addition, the required speed reduction allowances were suggested given the design speeds if the luminous intensity remains unchanged.

The present study was conducted to investigate the effect of environmental temperature and backfat thickness (BT) on the reproductive performance of lactating sows. Sixty crossbred sows were allotted to four groups in a 2×2 factorial arrangement by environmental temperature (high temperature [HT], 27.5±1.76℃; low temperature [LT], 23.3±0.89℃) and BT (<20 mm, average 17.70 mm; ≥20 mm, average 23.20 mm) from July to August 2019. Sows in the HT group experienced a greater change in BT and a lower feed intake. Losses in body weight and BT were lower in sows with <20 mm BT than in those with ≥20 mm BT. Sows with low BT had a lower weaning-to-estrus interval than sows with high BT (5.20, 4.93 d vs. 5.87, 5.60 d, respectively). Piglet survivability was lower in the HT group (90.31%) than in the LT group (94.87%). Piglet weaning weight and average daily weight gain were greater in sows with <20 mm BT (5.75 kg and 201.46 g, respectively) than in those with ≥20 mm BT (5.49 kg and 188.41 g, respectively). Sows in the HT group had higher cortisol concentrations than those in the LT group (post-farrowing: HT 7.86 μg/mL vs. LT 6.04 μg/mL; weanling: HT 5.48 μg/mL vs. LT 4.40 μg/mL). In conclusion, environmental temperature adversely influenced sow performance and cortisol levels. Moreover, sows with low BT had a greater weaning-to-estrus interval when subjected to heat stress.

본 연구에서는 두 종류의 도너-억셉터 (D-A) 타입 고분자들을 Stille coupling 반응을 통하여 중합한 뒤, 이들 을 고분자 기반 유기 태양전지의 광활성 층으로 적용하였다. Benzodithiophene 전자 주게와 pyrazinoquinoxaline 전 자 받게를 활용하여 고분자들을 합성하였고, 전자 주게와 전자 받게가 직접 연결된 고분자를 PB-TMPQ 그리고 둘 사 이에 티오펜 π-bridge가 도입된 고분자를 PB-TTMPQ라 각각 명명하였다. 기본적인 화학 구조의 검증과 더불어, 고분 자들의 광학적 및 전기화학적 특성에 대한 분석 또한 실시하였다. 최종적으로 inverted-type 구조의 소자를 이용하여 고분자들의 광전지 특성들을 분석하였으며, PB-TMPQ와 PB-TTMPQ의 전력변환 효율은 각각 1.01%로 0.83%로 관측 되었다. 따라서, π-bridge의 도입이 pyrazinoquinoxaline 기반 고분자의 광전지 특성을 큰 영향을 미친다는 것이 확인 되었으며, 이러한 결과는 향후 pyrazinoquinoxaline 기반 고분자의 구조-물성 간 상관관계 연구에 활용될 수 있을 것 이다.

In the present study, we investigated the austenite stability of a sintered Fe-based nanocrystalline alloy. The volume fraction of austenite was measured based on the X-ray diffraction data of sintered Fe-based nanocrystalline alloys, which were prepared by high-energy ball milling and spark plasma sintering. The sintered alloy samples showed a higher volume fraction of austenite at room temperature as compared to the equilibrium volume fraction of austenite obtained using thermodynamic calculations, which resulted from the nanosized crystalline structure of the sintered alloy. It was proved that the austenite stability of the sintered Fe-based alloy increased with a rise in the amount of austenite stabilizing elements such as Mn, Ni, and C; however, it increased more effectively with a decrease in the actual grain size. Furthermore, we proposed a new equation to predict the martensite starting temperature for sintered Fe-based alloys.