• Journal of Sport and Applied Science
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• 제3권2호
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• pp.17-27
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• 2019

Purpose: This study is to conduct usability evaluations from the perspective of developing comfort-shoes for the middle-aged and elderly to identify key factors and derive implications for optimal comfort-shoes production. Research design, data, and methodology: A total of 10 middle-aged and elderly women in their 50s and 60s were selected as eligible for the rescue. For data collection, the study was conducted in a Gang Survey, where pre-explanations, shoes test, and interviews were conducted. The collected data were analyzed in a total of four stages. In step 1, the contents obtained through interviews with the subjects were recorded in text, organized and analyzed systematically, and in step 2, unnecessary vocabulary, sentences, and overlapping opinions were eliminated. In step 3, we classified areas around key functions and carried out categorization tasks. Finally, in Step 4, the results and implications of the study were derived by classifying each usability evaluation shoe as positive and negative text around categorized data. Results: There are a total of seven factors for comfort-shoes usability evaluation, which are categorized as cushion, fitting, stability, flexibility, lightweight, comfort, and pressure. Positive/negative factors for the derived usability evaluation factors were shown in the form of a positive-centered, negative-centered, and positive-mixed mix for each of the four products. Positive-focused products are VA products, which are seven times more positive than negative factors. Negative-centered products are CL and SA products, which are five times more negative than positive factors. Positive mixing was a CA product with a ratio of 1:1. Text-based usability evaluations allow us to proceed with analysis based on more scientific data rather than simply listening to opinions and judging by comments. Conclusions: The study discussed implications of developing comfort-shoes for middle-aged consumers and future directions were discussed.

• 식품과학과 산업
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• 제53권3호
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• pp.277-283
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• 2020

식품의 보존성 및 안전성 증대를 위해 살균이 필수적이다. 일반적으로 가열 살균 기술이 가장 많이 사용되고 있으나, 공정 중 식품의 품질 저하를 막기 위한 살균 기술로 신공정 기술을 활용한 비가열 살균 기술의 중요성이 대두되고 있다. 그 중에서도 초음파 기술은 특유의 캐비테이션 현상으로 미생물의 파괴가 촉진되어 살균 효과를 내는 것으로 알려져 있다. 초음파 기술 단독으로는 사멸 효과가 낮으며, 다양한 공정기술과 함께 적용하여 사멸 효과를 극대화할 수 있는 기술 개발을 위한 연구가 활발히 진행되고 있다. 초음파와 함께 처리할 수 있는 공정으로는 가열, 고압, 화학적 처리 등 전통적인 살균 방법 뿐 아니라 자외선 조사, PEF 등 신공정 기술이 있다. 초음파 기술을 적용한 다른 공정과 달리 살균 기술은 아직 실험실 수준에 머물러 있어 산업적 적용을 위한 장치의 개발, 최적 공정 확립 등 추가 연구가 필요하다.

• Composites Research
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• 제33권6호
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• pp.390-394
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• 2020

탄소섬유 스프레드 토우를 제조하는 과정에서 섬유 손상이 발생하며, 이는 스프레딩 과정에서 장비와 섬유 사이 혹은 섬유 간의 마찰로 발생한다. 이로 인해, 재료 및 장비조건에 따라 프로세스 성능에 차이가 발생하고, 제품 물성이 하락한다. 섬유 손상을 최소화하는 것은 스프레드 토우를 제조하는 공정에서 반드시 고려되어야 한다. 본 연구에서는 공기를 이용한 탄소섬유 스프레딩 공정에서 탄소섬유의 필라멘트 수와 사이징 함량, 탄소섬유토우 스프레딩 장비의 공정 변수(초기섬유장력, 열풍온도, 진공압력)를 달리하여 스프레드 토우의 공정성능 변화를 관찰하였다. 탄소섬유 품종에 따른 조건 별 최적조건에서 제조된 샘플을 이용해 인장강도를 평가하여, 탄소섬유의 손상에 따른 기계적 물성 감소를 확인하였다.

• Journal of Dental Anesthesia and Pain Medicine
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• 제21권2호
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• pp.129-137
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• 2021

Background: Inappropriate use of intravenous and inhaled anesthetics may be dangerous in infants undergoing facial cleft surgeries. This study primarily aimed to compare the effect of infraorbital nerve block on sevoflurane requirement in infants undergoing cheiloplasty. Intraoperative opioid consumption, hemodynamics, blood glucose levels, extubation time, and delirium were also compared. Methods: This prospective, randomized, double-blinded study was conducted in 34 infants undergoing cheiloplasty under general anesthesia. After induction, group A received bilateral infraorbital nerve block with 0.5 mL of 0.5% bupivacaine and group B 0.5 mL saline. An increase in heart rate or blood pressure > 20% was managed by increasing sevoflurane by 2-2.5%, followed by fentanyl 0.5 ㎍/kg bolus. The chi-square test and independent-sample t-test were used where applicable. Results: Demographics, duration of surgery, and intravenous fluids used were comparable between the groups. Compared to group A, patients in group B had significantly higher consumption of fentanyl (14.2 ± 4.4 ㎍ vs. 22.1 ± 6.2 ㎍) and sevoflurane (14.2 ± 4.8 mL vs. 26.8 ± 15.6 mL). Intraoperative hemodynamic parameters were significantly lower in group A, the number of times increases in hemodynamic parameters occurred, and fentanyl supplemental bolus was required remained significantly lower in group A than in group B. Intraoperative glycemic levels remained higher in group B, and the extubation time was significantly shorter in group A than in group B (4.40 ± 1.60 min vs. 9.2 ± 2.18 min). Group A had a lesser occurrence of postoperative delirium. Conclusion: Supplemental infraorbital block in infants undergoing cheiloplasty under general anesthesia resulted in significantly decreased anesthetic requirements and optimal hemodynamic and glycemic levels with faster extubation and lesser delirium.

• Structural Engineering and Mechanics
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• 제77권2호
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• pp.167-177
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• 2021

Due to various benefits such as unlimited degrees of freedom, environment adaptability, and safety for humans, engineers have used soft materials with hyperelastic behavior in various industrial, medical, rescue, and other sectors. One of the applications of these materials in the fabrication of bending soft actuators (SA) is that they have eliminated many problems in the actuators such as production cost, mechanical complexity, and design algorithm. However, SA has complexities, such as predicting and monitoring behavior despite the many benefits. The first part of this paper deals with the prediction of SA behavior through mathematical models such as Ogden and Darijani, and its comparison with the results of experiments. At first, by examining different geometric models, the cubic structure was selected as the optimal structure in the investigated models. This geometrical structure at the same pressure showed the most significant bending in the simulation. The simulation results were then compared with experimental, and the final gripper model was designed and manufactured using a 3D printer with silicone rubber as for the polymer part. This geometrical structure is capable of bending up to a 90-degree angle at 70 kPa in less than 2 seconds. The second section is dedicated to monitoring the bending behavior created by the strain sensors with different sensitivity and stretchability. In the fabrication of the sensors, silicon is used as a soft material with hyperelastic behavior and carbon fiber as a conductive material in the soft material substrate. The SA designed in this paper is capable of deforming up to 1000 cycles without changing its characteristics and capable of moving objects weigh up to 1200 g. This SA has the capability of being used in soft robots and artificial hand making for high-speed objects harvesting.

• Geomechanics and Engineering
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• 제24권5호
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• pp.479-490
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• 2021

Pre-drainage of groundwater in the roof aquifer by boreholes is the main method for prevention of roof water disaster, and the drop in the water level during the drainage leads to the variation of the local stress in the overlying strata. Based on a multitude of boreholes for groundwater drainage from aquifer above the 1303 mining face of Longyun Coal Mine, theoretical analysis and numerical simulation are used to investigate the local stress variation in the process of borehole drainage. The results show that due to the drop in the water level of the roof aquifer during the drainage, the stress around the borehole gradually evolved. From the center of the borehole to the outside, a stress-relaxed zone, a stress-elevated zone, and a stress-recovered zone are sequentially formed. Along with the expansion of drainage influence, the stress peak in the stress-elevated zone also moves to the outside. When the radius of influence develops to the maximum, the stress peak position no longer moves outward. When the coal mining face advances to the drainage influence range, the abutment pressure in front of the mining face is superimposed with the high local stress around the borehole, which increases the risk of stress concentration. The present study provides a reference for the stress concentration caused by borehole drainage, which can be potentially utilized in the optimal arrangement of drainage boreholes in underground mining.

• 반도체디스플레이기술학회지
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• 제21권4호
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• pp.81-85
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• 2022

Mist-CVD is known to have advantages of low cost and high productivity method since the precursor solution is misting with an ultrasonic generator and reacted on the substrate under vacuum-free conditions of atmospheric pressure. However, since the deposition distribution is not uniform, various efforts have been made to derive optimal conditions by changing the angle of the substrate and the position of the outlet to improve the result of the preceding study. Therefore, in this study, a deposition distribution uniformity model was derived through the shape and position of the substrate support and the conditions of inlet flow rate using the particle tracking method of computational fluid dynamics (CFD). The results of analysis were compared with the previous studies through experiment. It was confirmed that the rate of deposition area was improved from 38.7% to 100%, and the rate of deposition uniformity was 79.07% which was higher than the predicted result of simulation. Particle tracking method can reduce trial and error in experiments and can be considered as a reliable prediction method.

• 공업화학
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• 제33권1호
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• pp.103-108
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• 2022

본 연구에서는 아이소소바이드(1,4:3,6-dianhydro-D-glucitol)로부터 그에 상응하는 아이소소바이드-디케톤[2,6-dioxabicyclo(3,3,0)octan-4,8-one]으로의 높은 선택적 전환을 통한 효율적인 루테늄/템포/나이트레이트 촉매 시스템 개발에 대해 보고한다. 미래의 제조 공정에서의 중요한 플랫폼 화합물 중 하나는 아이소소바이드이다. 오랜 시간 동안, TEMPO(2,2,6,6-tetramethylpiperidine-N-oxyl)는 알코올을 카보닐 화합물로 변환하는데 사용되어 왔다. 본 화학 반응에서는 산소 1atm 압력하에, Ru (10 mol%), TEMPO (5 mol%), 질산나트륨(0.03 mmol) 그리고 아이소소바이드(0.5 mmol)를 용매 아세트산(3 ml)을 사용하여 최적화되었다. 이러한 촉매 시스템은 이중 산화 촉매 반응 메커니즘에 대한 가능성뿐만 아니라, 생성물에 대한 원하는 반응물의 높은 선택성(> 97%)과 수율(87%)을 보여주었다.

• 대한의용생체공학회:의공학회지
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• 제44권1호
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• pp.85-91
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• 2023

Stress urinary incontinence (SUI) occurs when abdominal pressure increases, such as sneezing, exercising, and laughing. Surgical and non-surgical treatments are the common methods of SUI treatment; however, the conventional treatments still require continuous and invasive treatment. Laser have been used to treat SUI, but excessive temperature increase often causes thermal burn on urethra tissue. Therefore, the optimal conditions must be considered to minimize the thermal damage for the laser treatment. The current study investigated the feasibility of the laser irradiation condition for SUI treatment using non-ablative 980 nm laser from a safety perspective through numerical simulations. COMSOL Multiphysics was used to analyze the numerical simulation model. The Pennes bioheat equation with the Beer's law was used to confirm spatio-temporal temperature distributions, and Arrhenius equation defined the thermal damage caused by the laser-induced heat. Ex vivo porcine urethral tissue was tested to validate the extent of both temperature distribution and thermal damage. The temperature distribution was symmetrical and uniformly observed in the urethra tissue. A muscle layer had a higher temperature (28.3 ℃) than mucosal (23.4 ℃) and submucosal layers (25.5 ℃). MT staining revealed no heat-induced collagen and muscle damage. Both control and treated groups showed the equivalent thickness and area of the urethral mucosal layer. Therefore, the proposed numerical simulation can predict the appropriate irradiation condition (20 W for 15 s) for the SUI treatment with minimal temperature-induced tissue.

• 한국기계가공학회지
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• 제21권5호
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• pp.98-104
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• 2022

When processing parts, the cutting oil can improve the cooling performance of the workpiece and tool to increase the precision of the workpiece or extend the life of the tool and facilitate chip extraction. Since such cutting oil has a harmful effect on the environment and the human body due to additives such as sulfur, research on a minimum lubrication supply method using an eco-friendly oil is recently underway. The minimum lubrication supply method minimizes the amount of cutting oil used during processing and processes it, which can reduce the amount of cutting oil used, but has a problem in that cooling performance efficiency is poor. Therefore, this study conducted a study on mist cooling of lubricants to reduce the amount of cutting oil used and maximize the cooling effect of processing heat generated during tapping processing. Spray pressure, processing speed, direction, and lubricant spray amount, which are considered to have an effect on cooling performance, were set as process conditions, and the effect on temperature was analyzed by performing an experiment using the box benquin method among experiments were analyzed. Through the experimental analysis results, the optimal conditions for mist and processing that maximize the cooling effect were derived, and the validity of the results derived through additional experiments was verified. In the case of processing by applying the mist lubrication method verified through this study, it is considered that high-precision processing is possible by improving the cooling effect.