• 제목/요약/키워드: air force

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MRG(Mechanical Rubber Goods) 보강사 제조시스템의 건조부에서의 배기구 형상이 유동 및 온도 분포에 미치는 영향에 관한 연구 (A Study on the Effect of the Shape of the Exhaust Port on the Flow and Temperature Distribution in the Drying Part of the MRG(Mechanical Rubber Goods) Reinforcing Yarn Manufacturing System)

  • 김환국;권혜인;도규회
    • 한국염색가공학회지
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    • 제34권2호
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    • pp.109-116
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    • 2022
  • Tire codes are made of materials such as hemp, cotton, rayon, nylon, steel, polyester, glass, and aramid are fiber reinforcement materials that go inside rubber to increase durability, driveability, and stability of vehicle tires. The reinforcement of the tire cord may construct a composite material using tires such as automobiles, trucks, aircraft, bicycles, and fibrous materials such as electric belts and hoses as reinforcement materials. Therefore, it is essential to ensure that the adhesive force between the rubber and the reinforced fiber exhibits the desired physical properties in the rubber composite material made of a rubber matrix with reinforced fibers. This study is a study on the heat treatment conditions for improving the adhesion strength of the tire cord and the reinforced fiber for tires. The core technology of the drying process is a uniform drying technology, which has a great influence on the quality of the reinforcement. Therefore, the uniform airflow distribution is determined by the geometry and operating conditions of the dryer. Therefore, this study carried out a numerical analysis of the shape of a drying nozzle for improving the performance of hot air drying in a dryer used for drying the coated reinforced fibers. In addition, the flow characteristics were examined through numerical analysis of the study on the change in the shape of the chamber affecting drying.

심한 결손부의 단계적 골증대술을 통한 임플란트 지지 고정성 보철 수복 증례 보고 (Implant-supported fixed prosthesis in patient with severe defects using staged GBR via 2-step augmentations: A case report)

  • 오세은;전지훈;박영범
    • 대한치과보철학회지
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    • 제60권4호
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    • pp.382-394
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    • 2022
  • 심한 치주염을 가진 환자의 치료는 환자의 개개 치아의 정확한 진단과 전략적인 치료 계획을 통해 단계적으로 진행되어야 한다. 임플란트 지지 고정성 보철 수복은 국소의치에 비해 환자의 만족도가 높고, 안정적인 수직 고경을 유지할 수 있는 장점이 있지만, 경조직이 부족한 다수 치아 결손 부위에서는 심미적인 측면의 실패와 치료 기간이 길어진다는 점의 단점이 있을 수 있다. 또한 통상의 고정성 보철물을 제작하고 장착하는 데에는 일정 기간이 소요되는데, 이 기간 동안 임시 보철물은 치아의 기계적, 생물학적, 심미적 요구 조건을 만족시켜야 한다. 이번 증례 보고에서는 상악과 하악의 부분 무치악 환자에서 단계적인 접근을 통한 임플란트 고정성 보철물을 수복한 증례를 보고하고자 한다.

얼굴 정보를 이용한 대형 카메라 네트워크에서의 사람 추적 시스템 (Human Tracking System in Large Camera Networks using Face Information)

  • 이영건
    • 한국정보통신학회논문지
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    • 제26권12호
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    • pp.1816-1825
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    • 2022
  • 본 논문에서는 다양한 해상도의 카메라를 사용하는 감시 카메라 네트워크에서 각 사람을 추적하는 새로운 접근 방식을 제안한다. 다수의 비겹침 카메라 상에서 사람 추적 시 기존에 사용되던 사람 특징 정보는 다양한 카메라 시야 조건에 쉽게 영향을 받는다. 이러한 한계를 극복하기 위해 제안하는 시스템은 외모 정보와 함께 얼굴 정보를 활용한다. 일반적으로 감시 카메라로 촬영하는 사람 영상은 해상도가 낮은 경우가 많기 때문에 추적을 용이하게 하기 위해 저해상도 얼굴에서도 유용한 특징을 추출할 수 있어야 한다. 제안하는 추적 방식에서 사람 얼굴 특징을 추출하기 위해 탐지된 얼굴을 정면화한 후 텍스쳐 기반의 특징을 추출한다. 또한 감시 카메라에 포착된 얼굴의 크기가 매우 작은 경우 얼굴을 확대하는 초해상도 기법도 함께 활용한다. 공개된 데이터셋인 Dana36을 이용하여 수행한 실험결과를 통해 제안된 알고리즘의 우수한 성능을 보여준다.

Efficacy and Safety of Cheong-A-Won Gagambang (JCE003) on Knee Osteoarthritis: Randomized Controlled Pilot Trial

  • Kong, Haejin;Kang, Jaehui;Lee, Hyun
    • Journal of Acupuncture Research
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    • 제39권3호
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    • pp.202-212
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    • 2022
  • Background: The aim of this study was to evaluate the effectiveness and safety of Cheong-A-Won Gagambang (JCE003) treatment for degenerative knee osteoarthritis. Methods: This was a single-center, randomized, double-blind, placebo-controlled pilot clinical trial. There were 36 adults with degenerative knee osteoarthritis who were randomly allocated into JCE003 1,000 mg, JCE003 2,000 mg, or the placebo group (in a 1:1:1 ratio). The participants received 12 weeks of treatment and had scheduled tests every 6 weeks. The primary outcomes were measured using the Korean Western Ontario and McMaster Universities scale, and the secondary outcomes were measured using the visual analog scale, European quality of life-5-dimensions, patient global impression of change, C-reactive protein, and erythrocyte sedimentation rate. Changes between baseline scores and scores following study completion were analyzed. Results: There were 29 participants whose data were analyzed in this study. The change of Korean Western Ontario and McMaster Universities, visual analog scale, European quality of life-5-dimensions scores showed significant improvement in the JCE003 1,000 mg group. The change of patient global impression of change was significantly improved in the placebo group. There were 14 adverse events, but there was no clinically significant relationship with the intake of JCE003 compared with the placebo. Conclusion: Taking JCE003 may be effective at improving knee pain in patients with degenerative knee osteoarthritis and appears to be safe. Based on this study, the concentration and feasibility of the test group may be used when conducting a large-scale clinical trial of degenerative knee osteoarthritis in the future.

비행착각에 의한 헬리콥터 사고 예방 프로그램 개발에 관한 연구 (A Study on the Development of Helicopter Accident Prevention Program by Spatial Disorientation)

  • 조영진
    • 한국항행학회논문지
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    • 제27권1호
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    • pp.8-15
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    • 2023
  • 조종사들을 대상으로 진행한 설문 결과에 따르면 252명 중 92%인 230명이 비행 중 비행착각을 경험한 적이 있다고 응답하였다. 이처럼 많은 조종사가 비행착각을 경험하고 있으며, 이는 항공기 사고와 인명 손실로 이어지는 주요 원인 중 하나이기 때문에 정확하게 파악하는 것이 중요하다. 그러나 국내의 경우 고정익항공기(비행기) 조종사를 위한 훈련 장비는 이미 개발되어 훈련하고 있거나, 최근 개발되어 훈련을 준비하는 등 적극적인 활동이 이루어지고 있으나, 헬리콥터 조종사를 위한 장비는 공군에서 일부 활용 가능하나, 이마저도 민간 조종사에게 지원할 수 있는 여건의 한계로 헬리콥터 조종사들이 비행착각 예방 교육 훈련을 받을 수 있는 환경은 전무하다. 따라서 헬리콥터 전용 시뮬레이터를 제작하고 헬리콥터 조종사 대상 비행 중 발생할 수 있는 비행착각을 예방하기 위한 프로그램을 제시하고, 추후 훈련 데이터를 기반으로 법, 제도적 방안을 제시하고자 한다.

VOF와 FSI 방법을 적용한 CBT 연소 정밀 모델링 및 해석 (CBT Combustion Precise Modeling and Analysis Using VOF and FSI Methods)

  • 강정석;박종근;성홍계
    • 한국추진공학회지
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    • 제26권5호
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    • pp.35-43
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    • 2022
  • 본 연구에서는 고체추진제를 사용하는 closed bomb test(CBT)의 연소에 대한 정밀 모델링 및 해석을 수행하였다. 기상과 고상을 동시에 해석하기 위해 fluid structure interaction(FSI) 기법을 사용하였으며 기체상과 그레인의 연소해석은 Eulerian 방법을, 그레인의 이동은 Lagrangian 방법을 적용하였다. 고체상의 그레인과 연소가스의 상호 작용은 소스텀을 통해 완전 결합(fully coupled) 되도록 하였다. 그레인의 연소거리와 연소면의 이동을 모사하기 위하여 volume of fluid(VOF) 방법을 사용하였고, 그레인에 작용하는 힘은 그레인 연소면에 작용하는 압력과 중력을 고려하고, VOF의 속도항에 그레인 연소속도와 그레인 이동속도를 고려하였다. 개발한 수치모델을 바탕으로 1개와 3개 그레인에 대한 연소해석을 수행하여 실험결과와 비교 검증하였다. 연소시에 나타나는 압력 섭동에 대한 음향장을 분석하였다.

Meat Quality Changes in Aged Pork Loin using Jeju Volcanic Scoria Earthenware

  • DongGyun Kim;SangHoon Lee;GwangHeun Kim;KyoungBo Ko;YounChul Ryu
    • 한국축산식품학회지
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    • 제43권5호
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    • pp.901-913
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    • 2023
  • This study aimed to investigate changes in the quality of meat aged using Jeju scoria earthenware. Water-holding properties, pH, color, tenderization, fatty acid composition, and free amino acid characteristics of aged pork loin were evaluated to determine the effects of wet and dry (normal and Jeju Scoria) aging methods and aging time (0, 10, 20, 30, and 40 days) on meat quality. The aging methods altered pH and CIE L* after 10 days of aging. However, the aging method did not alter the pH and CIE L* of the aged pork loin after 10 days of aging. The shear force was significantly lower in the Scoria aging method than in the wet aging method after 10 and 20 days of aging. Both the normal and Scoria aging methods increased aging loss compared to the wet aging method, which could be attributed to longer air exposure times of the two non-packaged aging methods than in the packaged aging method. The scoria aging method had significantly higher contents and ratios of saturated (SFA) to mono-unsaturated fatty acids but lower ratios of poly-unsaturated fatty acids to SFA than the wet aging method. The content of most free amino acids significantly increased with aging time, especially those related to the sweet, and umami categories. In summary, this study suggests that the Scoria aging method provides positive aspects of eating quality, such as improvement of meat tenderness and taste, including umami, with minimum changes in the overall meat quality.

An objective assessment of the impact of tendon retraction on sleep efficiency in patients with full-thickness rotator cuff tears: a prospective cohort study

  • Ashley E. MacConnell;William Davis;Rebecca Burr;Andrew Schneider;Lara R Dugas;Cara Joyce;Dane H. Salazar;Nickolas G. Garbis
    • Clinics in Shoulder and Elbow
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    • 제26권2호
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    • pp.169-174
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    • 2023
  • Background: Sleep quality, quantity, and efficiency have all been demonstrated to be adversely affected by rotator cuff pathology. Previous measures of assessing the impact of rotator cuff pathology on sleep have been largely subjective in nature. This study was undertaken to objectively analyze this relationship through the use of activity monitors. Methods: Patients with full-thickness rotator cuff tears at a single institution were prospectively enrolled between 2018 and 2020. Waist-worn accelerometers were provided for the patients to use each night for 14 days. Sleep efficiency was calculated using the ratio of the time spent sleeping to the total amount of time that was spent in bed. Retraction of the rotator cuff tear was classified using the Patte staging system. Results: This study included 36 patients: 18 with Patte stage 1 disease, 14 with Patte stage 2 disease, and 4 patients with Patte stage 3 disease. During the study, 25 participants wore the monitor on multiple nights, and ultimately their data was used for the analysis. No difference in the median sleep efficiency was appreciated amongst these groups (P>0.1), with each cohort of patients demonstrating a generally high sleep efficiency. Conclusions: The severity of retraction of the rotator cuff tear did not appear to correlate with changes in sleep efficiency for patients (P>0.1). These findings can better inform providers on how to counsel their patients who present with complaints of poor sleep in the setting of full-thickness rotator cuff tears.

고품질 다수확 원목 상황버섯 재배 경영사례 조사 (Study Case on the Log Cultivation of Phellinus baumii for It's High Quality and Large Quantity)

  • 서규선;장현유;김순근
    • 현장농수산연구지
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    • 제10권1호
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    • pp.153-167
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    • 2008
  • High temperature and natural sun light are considered as the core conditions for high quality and large quantity of Phellinus baumii production. However still now on there has been a mistake of excessively cutting off the natural light by spreading the closing nets on the mushroom cultivating house. For an example there are many houses where the closing nets under the roofs be extended to cover the sides of the houses, which way prevents the mushrooms in the houses from receiving sufficient natural sun light and getting the temperature sufficiently to grow so that the quantity and quality of the produced mushrooms are lowered even though the mushrooms can grow in those conditions. In order to avoid this mistake, the closing nets must be placed on the roofs of the houses only without dropping them to cover the sides. Further more when the closing nets are placed triply at the beginning stage of Phellinus baumii's growth in the house, the nets restrain the internal temperature of the house going up and intercept the natural bright light flowing into the house so that the growing tardiness occur to the Phellinus baumii. Therefore the roof only must have been covered by the closing net for 65% cutting off the light until May, and then covered by double folded the net for June, triple folded the net for July and August, double folded the net for September, and the single net for October. When the ventilation in the house has been maintained until the house tightly balloon out through controling lifting force of internal air, the Phellinus baumii can grow well while the bed logs themselves aren't dried out. Marketing is also very much important as well as increasing quality and quantity of Phellinus baumii production.

Maxillary sinus volumetric changes in jet aircraft pilots: A multislice computed tomography pilot study

  • Yeda da Silva;Luciana Munhoz;Jose Rodrigues Parga Filho;Andreza Gomes Damasceno;Cesar Felipe Franca da Rosa;Eduardo Bilaqui Zukovski;Erik Zhu Teng;Claudio Campi de Castro
    • Imaging Science in Dentistry
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    • 제53권1호
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    • pp.53-60
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    • 2023
  • Purpose: This study evaluated maxillary sinus volume changes in military jet aircraft pilot candidates before and after the training program, in comparison with a control group, considering the effects of pressurization, altitude, and total flight hours, through multislice computed tomography. Materials and Methods: Fifteen fighter pilots were evaluated before initiating the training program and after the final approval. The control group consisted of 41 young adults who had not flown during their military career. The volumes of each maxillary sinus were measured individually before and at the end of the training program. Results: When comparing the initial and final volumes in the pilots, a statistically significant increase was observed both in the left and right maxillary sinuses. When evaluating the average total volume of the maxillary sinuses(i.e., the average volume of the right and left maxillary sinuses together), a significant increase in the volume of the maxillary sinuses was observed in the pilot group when compared to the control group. Conclusion: The maxillary sinus volumes in aircraft pilot candidates increased after the 8-month training program. This may be explained by changes in the gravitational force, the expansion of gas, and positive pressure from oxygen masks. This unprecedented investigation among pilots might lead to other investigations considering paranasal sinus alterations in this singular population.