• 대한본초학회지
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• 제21권1호
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• pp.9-15
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• 2006

Objectives : Lonicerae Flos has been known as a useful plant with anti-inflammatory, antioxidative and immunosuppressive activity. To evaluate anti-inflammatory effect of Lonicerae Flos, we treated Lonicerae Flos-skin in animal model system induced contact hypersensitivity. Methods : Contact hypersensitivity, a local inflammatory response of the skin, was induced by spreading the right ear of BALB/c mouse with 1% DNCB. Lonicerae Flos-skin was prepared by dissolving 1% water extract of Lonicerae Flos in skin vehicle and treated everyday for 2 weeks on the right ear. Results : Lonicerae Flos-skin significantly reduced a mouse ear thickness swelled by 1% of DNCB treatment compared with skin vehicle-treated control group. Lonicerae Flos-skin also reduced IgG and IgE in serum obtained from blood of 1% DNCB-treated mouse. Conclusion : These results showed that Lonicerae Flos-skin could be used as a pharmaceutical material with antiinflammatory effects by reducing IgG and IgE in contact hypersensitivity mouse model by DNCB.

• Structural Engineering and Mechanics
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• 제84권6호
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• pp.799-811
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• 2022

Adhesive bonding has seen rapid development in recent years, with emphasis to composite patch repairing processes of geometric defects in aeronautical structures. However, its use is still limited given its low resistance to climatic conditions and requirement of specialized labor to avoid fabrication induced defects, such as air bubbles, cracks, and cavities. This work aims to numerically analyze, by the finite element method, the failure behavior of a damaged plate, in the form of a bonding defect, and repaired by an adhesively bonded composite patch. The position and size of the defect were studied. The results of the numerical analysis clearly showed that the position of the defect in the adhesive layer has a large effect on the value of J-Integral. The reduction in the value of J-Integral is also related to the composite stacking sequence which, according to the mechanical properties of the ply, provides better load transfer from the plate to the repair piece through the adhesive. In addition, the increase in the applied load significantly affects the value of the J-Integral at the crack tip in the presence of a bonding defect, even for small dimensions, by reducing the load transfer.

• Earthquakes and Structures
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• 제24권1호
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• pp.1-9
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• 2023

A model for calculating structure interacted mechanics is proposed. A structural interaction model and controller design based on tuned mass damping (TMD) was developed to control the induced vibration. A key point is to introduce a new analytical model to evaluate the properties of the TMD that recognizes the motion-dependent nonlinear response observed in the simulations. Aiming at the problem of increased current harmonics and low efficiency of permanent magnet synchronous motors for electric vehicles due to dead time effect, a dead time compensation method based on neural network filter and current polarity detection is proposed. Firstly, the DC components and the higher harmonic components of the motor currents are obtained by virtue of what the neural network filters and the extracted harmonic currents are adjusted to the required compensation voltages by virtue of what the neural network filters. Then, the extracted DC components are used for current polarity dead time compensation control to avert the false compensation when currents approach zero. The neural network filter method extracts the required compensation voltages from the speed component and the current polarity detection compensation method obtains the required compensation voltages by discriminating the current polarity. The combination of the two methods can more precisely compensate the dead time effect of the control system to improve the control performance. Furthermore, based on the relaxed method, the intelligent approach of stability criterion can be regulated appropriately and the artificial TMD was found to be effective in reducing cross-wind vibrations.

• 소성∙가공
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• 제32권2호
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• pp.67-73
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• 2023

To overcome a climate change, manufacturing complex-shaped electric mobility parts becomes one of the important issues for enhancing a performance of motor with reducing their weight. Therefore, development of laser-based additive manufacturing shed on light due to their flexible manufacturing capacity that can be suitable to solve the poor formability of Fe-Si alloys for electric mobility parts. Although there are several studies existed to optimize the performance of additively manufactured Fe-Si alloys, the post-annealing effect was not well investigated yet though this is important to control the texture and mechanical properties of additively manufactured parts. In the present work, annealing effect on the mechanical property and microstructure of additively manufactured Fe-4.5Si alloy was investigated. Because of the ordered phase initiation after annealing, the hardness of additively manufactured Fe-4.5Si alloy increased up to 1173 K while a hardness drop occurs at the 1273 K condition due to the micro-crack initiation. The response surface methodology result represents the 1173 K-5 h sample is an optimal condition to maximize the mechanical property of additively manufactured alloy without micro-cracks.

• Elastomers and Composites
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• 제59권1호
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• pp.8-16
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• 2024

As regulations on greenhouse gas emission have strengthened globally, the demand for improved fuel efficiency in automobiles continues to rise. In response, the tire industry is actively conducting research to improve fuel efficiency by enhancing tire performance. In this study, silica-filled epoxidized natural rubber (ENR)/butadiene rubber (BR) blend compounds were manufactured according to ENR types and silica contents, and their physical properties and vulcanizate structure were evaluated. ENR-50, which has a higher epoxide content than ENR-25, exhibited stronger filler-rubber interaction, resulting in superior abrasion resistance. In addition, because of its high glass transition temperature (T_g), the wet grip performance of ENR-50 improved, even though the rolling resistance increased. Increasing the amount of silica had little effect on the abrasion resistance due to the increase in filler-rubber interaction and decrease in toughness. In addition, ENR-50 exhibited better wet grip performance; however, the rolling resistance increased. The results indicated that truck bus radial (TBR) tire tread compounds can be designed by applying ENR-50 to improve wear resistance and wet grip performance. In addition, by applying ENR-25 and reducing the silica contents improve fuel efficiency.

• 한국발생생물학회지:발생과생식
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• 제20권3호
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• pp.255-266
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• 2016

The optimum concentrations of clove oil as an anesthetic for olive flounder (Paralichthys olivaceus) and the stress response of the fish to clove oil anesthesia were determined over a range of water temperatures, and investigated in a simulated transport experiment using analysis of various water and physiological parameters. While the time for induction of anesthesia decreased significantly as both the concentration of clove oil and water temperature increased, the recovery time increased significantly (P<0.05). The plasma cortisol concentration in fish at each temperature increased significantly up to 12 h following exposure (P<0.05), then decreased to 48 h (P<0.05). The DO dissolved oxygen concentrations, pH values, and the fish respiratory frequencies decreased over 6 h following exposure to clove oil in all experimental groups (P<0.05), whereas the $NH_4{^+}$ and $CO_2$ concentrations in all experimental groups increased up to 6 h (P<0.05). The pH values and DO concentrations increased with increasing clove oil concentration (P<0.05) in the 6 h following exposure, and the $CO_2$ and $NH_4{^+}$ concentrations and the respiratory frequencies decreased with increasing clove oil concentration (P<0.05). The results of this experiment suggest that clove oil reduced the metabolic activity of olive flounder, thus reducing $NH_4{^+}$ excretion and $O_2$ consumption. In conclusion, clove oil appears to be a cost-effective and efficient anesthetic that is safe for use and non-toxic to the fish and users. Its use provides the potential for improved transportation of olive flounder.

• 한국콘텐츠학회논문지
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• 제9권3호
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• pp.232-240
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• 2009

본 연구는 노인 스트레스 감소를 위한 명상 프로그램의 효과성을 검증하였다. 명상 프로그램은 한국형 마음챙김 명상 프로그램과 크리야 요가로 구성하였다. 프로그램은 노인집단에서 명상집단과 통제집단을 대상으로 스트레스 반응성, 우울, 불안, 삶의 질을 종속변인으로 하여 사전-사후검사를 통해 효과 검증을 하였다. 연구결과 노인 스트레스 감소를 위한 명상 프로그램이 명상집단에서 노인의 불안, 우울, 스트레스 반응성이 사전-사후검사에서 유의한 감소를 보였고, 사후검사 결과 집단비교에서도 통제 집단과 유의한 차이를 보였다. 또한 명상집단은 삶의 질의 사전-사후검사에서 유의한 증가를 보였고, 사후검사 결과 통제 집단과 유의한 차이를 보였다. 따라서 노인 스트레스 감소를 위한 명상 프로그램이 노인의 불안, 우울, 스트레스 반응성을 낮추고, 삶의 질을 개선시키는 연구 결과가 나타났다. 본 연구 결과를 추후연구를 위하여 논의하였다.

• 한국안전학회지
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• 제8권1호
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• pp.80-87
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• 1993

본 논문은 에너지 분산 장치의 일종인 점탄성 감쇠기를 설치한 건물의 거동에 관한 실험 및 해석적 연구를 다루고자 한다. 지진 모형 실험 장치를 이용하여 감쇠기를 설치한 건물의 구조응답을 구하고. 이를 감쇠기를 설치하지 않은 건물에 대하여 행해진 비탄성 해석 결과와 비교한다. 결론적으로 말하면. 점탄성 감쇠기는 강지진 하중에 의하여 건물에 발생한 과도한 진동을 감소시키는데 효과적이다 일반적으로 점탄성 감쇠기를 건물에 설치함으로써 감쇠비와 함께 강성도가 증가하여 지진 응답을 감소시키는데 기여하나, 대부분은 감쇠기의 역할에 의해 증가된 감쇠비의 영향인 것으로 밝혀졌다. 모드 변형에너지법을 이용하여 감쇠기에 의해 증가된 등가구조 감쇠를 성공적으로 예측할 수 있으며 따라서 점탄성 감쇠기를 설치한 건물의 지진 응답이 일반적인 모드 해석 기법을 이용한 수치모형해석에 의해 정확히 예측된다.

• Korean Journal of Anesthesiology
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• 제71권6호
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• pp.453-458
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• 2018

Background: Pain on injection is a limitation with propofol use. The effect of the Valsalva maneuver on pain during propofol injection has not been studied. This maneuver reduces pain through the sinoaortic baroreceptor reflex arc and by distraction. We aimed to assess the efficacy of the Valsalva maneuver in reducing pain during propofol injection. Methods: Eighty American Society of Anesthesiologists class I adult patients undergoing general anesthesia were enrolled and divided into two groups of 40 each. Group I (Valsalva) patients blew into a sphygmomanometer tube raising the mercury column up to 30 mmHg for 20 seconds, while Group II (Control) patients did not. Anesthesia was induced with 1% propofol immediately afterwards. Pain was assessed on a 10-point visual analog scale (VAS), where 0 represented no pain, and 10, the worst imaginable pain, and a 4-point withdrawal response score, where 0 represented no pain, and 3, the worst imaginable pain. Scores were presented as median (interquartile range). Results: We analyzed the data of 70 patients. The incidence of pain was significantly lower in the Valsalva than in the control group (53% vs. 78%, P = 0.029). The withdrawal response score was significantly lower in the Valsalva group (1.00 [0.00-1.00] vs. 2.00 [2.00-3.00], P < 0.001). The VAS score was significantly lower in the Valsalva group (1.00 [0.00-4.00] vs. 7.00 [6.25-8.00], P < 0.001). Conclusions: A prior Valsalva maneuver is effective in attenuating injection pain due to propofol; it is advantageous in being a non-pharmacological, safe, easy, and time-effective technique.

• 대한통합의학회지
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• 제9권3호
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• pp.111-124
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• 2021

Purpose : The purpose of this study is to evaluate whether physical ability is improved by body stabilization, develop training methods to improve physical fitness factors suitable for body conditions, and provide future management and exercise materials to improve Taekwondo athletes' performance, after conducting the Body stabilization exercise (BSE) program on 22 elementary school Taekwondo athletes for 10 weeks to strengthen core muscles and evaluating Visual response speed test (VRST), Functional movement screen (FMS), Y-Balance test (YBT) and Vital capacity (VC). Methods : In order to examine the impact of the BSE program on Taekwondo athletes' VRST, FMS, YBT and VC this study conducted individual evaluations on all subjects, including VRST, FMS, YBT and VC before applying the programs, and compared exercise effects before and after the program, before and after exercise by a certain period. Results : After exercising, strength and quickness were improved significantly and reaction time was significantly shortened (p<.001). The total score of FMS was improved from 10.86±1.17 before to 11.68±0.99 after exercising, was statistically significant (p=.014). YBT was significantly improved from 91.11±4.84 before to 95.68±5.15 after exercising (p<.001). VC improved was statistically significant (p<.001). Conclusion : In conclusion, the BSE athletic program is expected to help Taekwondo athletes perform well by preventing and reducing injuries through the improvement of muscular strength, strength, speed, agility, step, kick, balance, flexibility, full body endurance and the combination of technical abilities.