• Journal of Apiculture
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• v.35 no.1
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• pp.9-19
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• 2020

The questionnaire survey for Apis cerana beekeepers and professionals on improved native bee hives was carried out and we compared the temperature, relative humidity(RH), and weight changes of 4 improved hives(Chungju, Miryang, Hanam, and Suwon) from May 1, 2019 to January 31, 2020. Beekeepers need vertical feeder, hive stand, entrance block, and separating panel as hive accessory devices. The average temperatures within brood area were kept constantly (31.3~35.1℃) and the low daily variances of temperature (≤1℃) in Chungju hive among tested hives were observed. The daily temperature variances in the separated space and on the top of winter cluster were not different among 4 hives. In correlation between the temperature of brood area and the number of combs, Chungju hive showed the highest correlation(80.4%) and between the temperature on top of winter clusters and outside temperature, 4 hives showed high positive correlation(76.8~87.1%). RH of brood area(45~60%) in all hives were kept relatively low and constant compared to the outside RH(60~85%). The stablest RH on the top of winter cluster was observed in Suwon hives (65~75%) The highest cumulative weight increase among hives and the high positive correlation(65~67%) between the change of cumulative hive weight and combs number of hives were shown in the Miryang and Chungju. Based on these results, A. cerana bees are able to manage constant temperature and RH within hives area for their colony life, which also effected by the types of hive.

• Journal of the Korean Orthopaedic Association
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• v.54 no.4
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• pp.336-342
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• 2019

Purpose: To examine the relationship between the progression of a kyphotic deformity and the magnetic resonance imaging (MRI) findings in conservatively treated osteoporotic thoracolumbar compression fracture patients. Materials and Methods: This study categorized the patients who underwent conservative treatment among those patients who underwent treatment under the suspicion of a thoracolumbar compression fracture from January 2007 to March 2016. Among them, this retrospective study included eighty-nine patients with osteoporosis and osteopenia with a bone density of less than -2.0 and single vertebral body fracture. This study examined the MRI of anterior longitudinal ligament or posterior longitudinal ligament injury, superior or inferior endplate disruption, superior of inferior intravertebral disc injury, the presence of low signal intensity on T2-weighted images, and bone edema of intravertebral bodies in fractured intravertebral bodies. Results: In cases where the superior endplate was disrupted or the level of bone edema of the intravertebral bodies was high, the kyphotic angle, wedge angle, and anterior vertebral compression showed remarkably progression. In the case of damage to the anterior longitudinal ligament or the superior disc, only the kyphotic angle was markedly prominent. On the T2-weighted images, low signal intensity lesions showed a high wedge angle and high anterior vertebral compression. On the other hand, there were no significant correlations among the posterior longitudinal ligament injury, inferior endplate disruption, inferior disc injury, and the progression of kyphotic deformity and vertebral compression. The risk factors that increase the kyphotic angle by more than 5° include the presence of injuries to the anterior longitudinal ligament, superior endplate disruption, and superior disc injury, and the risk factors were 21.3, 5.1, and 8.5 times higher than those of the uninjured case, and the risk differed according to the level of bone edema. Conclusion: An osteoporotic thoracolumbar compression fracture in osteoporotic or osteopenic patients, anterior longitudinal ligament injury, superior endplate and intravertebral disc injury, and high level of edema in the MRI were critical factors that increases the risk of kyphotic deformity.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.3
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• pp.640-655
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• 2018

Recently, the construction of the urban area has been rapidly increasing, and the excavation work of the ground has been frequently performed at the upper part of the existing underground structures. Especially, when the structure is constructed after the excavation of the ground, the loading and unloading process in the ground under the excavation basement can affect the existing underground structures. Therefore, in order to maintain the stability of the existing underground structure due to the excavation of the ground, it is necessary to accurately grasp the influence of the excavation and the structure load in the adjoining part. In this study, the effect of the excavation of the ground and the new structure load on the existing tunnel was experimentally implemented and the influence of the adjacent construction on the existing tunnel was investigated. For this purpose a large testing model with 1/5 scale of the actual size was manufactured. The influence of ground excavation, width of the load due to new structure, and distance between centers of tunnel and of excavation on the existing tunnel was investigated. In this study, it was confirmed that the influence on the existing tunnel gets larger, as the excavation depth get deeper. At the same distance, it was confirmed that the tunnel displacement increased up to three times according to the increase of the building load width. That is, the load width influences the existing tunnel larger than the excavation depth. As the impact of the distance between centers of tunnel and of excavation, it was confirmed that tunnel crown displacement decreased by 48%. The result showed that a tunnel is located in the range of 1D (D: tunnel diameter) from the center of excavation, the effect of excavation is the largest.

• Journal of the Korea Concrete Institute
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• v.22 no.5
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• pp.667-673
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• 2010

The near fault ground motion (NFGM) is characterized by a single long period velocity pulse with large magnitude. NFGMs have been observed in recent strong earthquakes, Northridge (1994), Japan Kobe (1995), Turkey Izmit (1999), China Sichuan (2008), Haiti (2010) etc. These strong earthquakes have caused considerable damage to infrastructures because the epicenter was close to the urban area, called as NFGM. Extensive research for the far field ground motion (FFGM) have been carried out in strong seismic region, but limited research have been done for NFGM in low or moderate seismic regions because of very few records. The purpose of this research is to investigate and analyze the seismic response of reinforced concrete bridge piers subjected to near-fault ground motions. The seismic performance of six RC bridge piers depending on three confinement steel ratios and three superstructure mass was investigated on the shaking table. From these experimental results, it was confirmed that the reduction of seismic performance was observed for test specimens with lower confinement steel ratio or more deck weight. The displacement ductility of RC bridge piers in terms of the stiffness degradation is proposed based on test results the shaking table.

• Korean Journal of Optics and Photonics
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• v.20 no.4
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• pp.217-222
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• 2009

In this paper, a low-cost hybrid-integrated tunable laser is realized using a polymer-ring resonator-based add/drop filter reflector and a reflective semiconductor optical amplifier. The add/drop filter reflector, composed of a double-ring resonator with different radii, can have characteristics of selective wavelength reflection and wide wavelength tuning with an aid of vernier effect derived from the radii difference. By hybrid-integrating the reflective semiconductor optical amplifier with the add/drop filter reflector, a tunable laser can be realized through an active alignment method. The hybrid laser exhibited a single mode lasing with side mode suppression ratio of 26 dB and full width half maximum of 0.03 nm. In addition, applying a low current as small as 25 mA onto electrodes over add/drop filter reflector, a wavelength tuning range of 17 nm could be obtained.

• Applied Chemistry for Engineering
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• v.10 no.8
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• pp.1200-1209
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• 1999

Prediction model was composed by optimal parameter estimation from best fitting on reactant temperature profile, inlet and outlet temperature of coolant and yield of dual fixed-bed catalytic reactor(FBCR) which was measured in the industrial field. In order to design the FBCR which could obtain maximum conversion and yield, we investigated the effect of catalyst bed length and reactor radius changes. An uniform activity FBCR showed the best performance at z = 2.8 m of total catalysst bed length in case of reactor radius r = 0.01241 m and z =2.80 m(upper layer: 1.88 m, lower layer: 0.92 m) under reactor radius r = 0.01254 m for a dual activities FCBR. In case of reactor radius changes, the axial temperature profile and maximum radial temperature was rapidly risen for radius increase. The reactor radius decrease showed the opposite result.

• Childhood Kidney Diseases
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• v.6 no.1
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• pp.68-74
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• 2002

Purpose: Suprapubic bladder aspiration(SBA) of urine is the most reliable method to obtain urine avoiding contamination in non-toilet trained infants. Ultrasonography is a useful tool for guiding the anatomic location as well as for direct visualization during procedure. We evaluated the success rate and complication of ultrasound(US) assisted SBA Methods. Sixty infants who visited Ewha Womans University Mokdong Hospital, with suspected urinary tract infection were randomly divided into the US assisted (n=32) and blind SBA(control, n=28) group. In US assisted SBA group, the anteroposterior(AP), transverse, and sagittal diameters and the volume of the bladder were measured. In the blind SBA group, urine was blindly aspirated when the urinary bladder was palpated at the suprapubic area. The rate of successful urine aspiration, the number of attempts until successful aspiration, aspirated urine volume were compared between the two groups. Results: The success rate was $100\%$(32/32) in the US assisted group, which was significantly higher than $85.7\%$(24/28) of the control group (P<0.05). The aspirated urine volume in the US assisted group was $7.4{\pm}3.7\;mL$, which was significantly higher than $4.5{\pm}3.4\;mL$ of the control group (P<0.05), The diameters and volume of bladder in successful aspiration were $2.1{\pm}0.7\;cm$ in AP diameter, $3.1{\pm}0.6\;cm$ in transverse diameter, $4.2{\pm}1.0\;cm$ in sagittal diameter and $15.2{\pm}10.4\;mL$ in volume, which were significantly higher than those ($1.7{\pm}0.3\;cm,\;1.7{\pm}0.3\;cm,\;1.8{\pm}0.7\;cm,\;2.4{\pm]0.6\;cm,\;3.9{\pm}2.5$) of the control group (P<0.05) The correlations between the AP(r=0.78), transverse (r=0.72), sagittal(r=0.91) diameter and bladder volume were significant (P<0.05). SBA was $100\%$ successful in the AP diameter >3 cm, transverse diameter >4 cm, depth >4 cm and bladder volume >5 mL. Conclusion: US assistance can significantly improve the success rate of SBA in infant with suspected urinary tract infection. (J Korean Soc Pediatr Nephrol 2002 ; 6 : 68-74)

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.324-332
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• 2017

The comparative experiments were conducted for single span greenhouses where cucumbers were cultivated to analyze the effect of heating between a carbon fiber electric heating element heater and an oil hot air heater in terms of the inside climate, energy consumption and plant growth. In order to analyze the effect of heating capacity, 6, 9, and 16 kW of electric powers were supplied to the electric heating element for same setting temperature of 15?. As a result, as the heating capacity increased, the number of ON-OFF cycles of the electric heating element and the temperature inside the greenhouse increased proportionally. In the comparison of two heaters, it was shown that the temperature and relative humidity distributions of the electric heating element installed greenhouse was much uniform than those of the oil hot air heater installed greenhouse. The heating energy consumptions during the heating period of 79 days were 867L for the oil hot air heater and 8,959 kWh for the electric heating element heater, and the heating costs were 607 and 403 thousand won respectively. In the electric heating element installed greenhouse, the cucumber growth was slightly better and the yield was 4.3% higher than those of the oil hot air heater installed greenhouse, but there were no statically significant difference in the cucumber growth and yield between greenhouses.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.71-71
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• 2017

농용트랙터의 운전자는 작업, 주행으로 인한 유해한 저주파 진동에 장시간 노출된다. 이에 따라 운전자에게 전달되는 노면 진동을 감소시켜주기 위한 전방차축 현가장치의 역할이 커지고 있다. 트랙터의 전방차축 현가장치는 주로 유압식으로 설계되어 있으며 이를 구성하는 유압요소 선정이 현가장치의 성능에 중요한 영향을 미친다. 하지만, 실제와 유사한 조건에서 트랙터 차체 무게만큼 큰 부하를 제공하여 유압회로의 성능을 실험하는 것은 비용과 시간 측면에서 비효율적이다. 본 연구에서는 이를 대체하기 위하여 개별 유압요소의 성능을 테스트 할 수 있는 현가장치 유압회로 요인 시험기를 설계제작 하였다. 이를 이용하여 개별 부품의 성능곡선을 센서를 이용 측정하였고 얻은 특성값을, 구성한 유압 시뮬레이션 모델에 반영하여 실제조건의 유압특성을 얻을 수 있는 유효한 시뮬레이션 모델 개발에 활용하였다. 또한, 실험실 환경에서 유압식 현가장치를 간소화 시킨 형태로 유압회로의 성능을 예비시험해 볼 수 있도록 다양한 센서를 장착 데이터를 취득할 수 있도록 하였다. 개발한 요인 시험기는 하부에 설치된 가진 실린더를 이용하여 상부에 설치된 현가장치 실린더의 스트로크 변위와 속도에 따른 힘을 측정할 수 있도록 구성하였다. 이를 위해 현가장치 실린더의 헤드부와 로드부에 각각 압력센서를 설치하였으며 헤드부, 로드부의 압력 차이와 로드셀을 이용해 측정한 가진 실린더의 힘의 관계를 확인하였다. 상부의 현가 실린더 장치는 복동 형태로 제작되어 헤드부, 로드부 양쪽 방향으로 유량이 흐를 수 있도록 설계되었다. 이를 이용해 헤드부와 로드부 사이에 어큐뮬레이터, 가변 오리피스, 릴리프 밸브 등으로 유압회로를 구성하였으며 어큐뮬레이터 용량에 따른 힘의 변화, 가변 오리피스의 개도량에 따라서 전달되는 힘의 크기 등을 측정하였다. 하부의 가진 실린더는 사인파, 삼각파, 계단 입력, DC 레벨 등의 신호를 발생시킬 수 있도록 제작되었다. 신호의 주파수는 0~4Hz, 범위에서 사용자가 조절할 수 있도록 설정되었으며 계단응답 성능 측정 시험을 평가한 결과 정상상태오차는 0.470mm~0.536mm, 입상시간은 0.194초~0.202초, 정착시간은 0.230초~0.421초로 나타났다.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.07a
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• pp.213-219
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• 2003

본 연구에서는 새로운 개념의 건조방법을 연구하여 곡물건조의 변화를 도모하고자 원적외선ㆍ열풍 복합열을 이용한 곡물건조기를 개발하게 되었다. 그 결과를 요약하면 다음과 같다. 가. 방사체길이가 1,680mm일 때 보다 1,470mm일 때가 방사체 표면온도가 높게 나타났고, 안정적인 것으로 나타났다. 열풍온도를 5$0^{\circ}C$로 설정했을 때 방사체의 표면온도분포는 280-29$0^{\circ}C$을 유지하였고, 6$0^{\circ}C$일 때는 30$0^{\circ}C$ 부근에서 유지되는 것을 확인할 수 있었다. 두 조건 모두에서 온도편차는 크게 나타나지 않았으므로 균일 건조가 이루어지는 것을 의미하며, 곡물의 품질저하에 영향을 미치지 않는 것으로 판단된다. 나. 열풍온도 5$0^{\circ}C$, 조사거리 125mm, 방사체 길이 1,470mm에서 방사체 길이방향으로 위치에 따라서 온도편차를 측정했을 때 버너를 기점으로 해서 근거리에서부터 원거리까지 균등 분할하여 5점의 온도를 측정하여 그 변화곡선을 분석한 결과 위치 3에서 온도가 높았고, 계속해서 위치 4, 5, 2, 1순으로 나타났다. 버너의 근거리에서보다 원거리에서 온도가 높게 나타난 것은 원적외선방사체를 통과하는 열풍이 빠져나가도록 되어있는 열풍유동관이 버너 원거리에 위치하고 있어 버너에 불꽃이 점화되면서 열풍이 방사체 끝쪽으로 유동되기 때문이다. 다. 건조실 수직면 길이방향의 온도는 열풍공기가 열풍실에서 유입되는 하단부이 온도가 높게 나타났고, 버너쪽과 송풍기쪽의 온도차는 나타나지 않아 온도분포의 좌우 대칭이 잘 되어 균일 건조가 되는 것으로 판단된다 이러한 현상은 건조실의 수평면에 대해서도 같은 현상이 나타났다. 라. 바닥면에서 상부로 올라갈수록 낮은 온도분포를 나타내고 있는 것은 상부에는 외부공기가 유입되면서 온도가 떨어지는 반면 하부에는 외부공기 유입이 적기 때문으로 사료된다. 또한 열풍실의 길이방향 위치별 온도 분포에서도 같은 현상으로 나타났고, 버너쪽과 송풍기쪽의 온도편차는 나타나지 않아 균일 건조를 기대할 수 있다. 마. 열풍온도를 45$^{\circ}C$로 설정하고 조사거리와 방사체 길이를 각각 119, 1,470mm로 하여 벼의 건조성능시험을 열풍건조기(대비구)와 비교시험 결과 시험구에서 건감률, 건조소요에너지가 각각 0.58%(w.b.), 470kcal/kg - water로 대비구보다 각각 건감율은 23% 높았고, 건조소요에너지는 2%의 절감되었다. 바. 건조기에서 발생되는 소음은 버너쪽 근처에서는 대비구 94.12㏈의 87%에 불과하였으나, 거리가 멀어질수록 차이는 크지 않았다. 이것은 버너에서 멀어질수록 외부적인 요인이 소음에 영향을 미쳤기 때문인 것으로 생각된다. 사. 시작기와 대비구간의 경제성에서 시작기의 구입가격이 20% 비싸기 때문에 시간당 고정비가 높았으나, 건조성능이 우수하여 건조비용이 69,350원/톤으로 대비구보다 14% 절감되는 것으로 나타났다.