• 대한기계학회논문집A
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• 제26권7호
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• pp.1416-1425
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• 2002

In this study, the effects of combined environmental factors on mechanical and thermal analysis properties of graphite/epoxy composites were evaluated by the use of an accelerated aging test. Environmental factors such as temperature, moisture. and ultraviolet were considered. A xenon-arc lamp was utilized for ultraviolet light. and exposure times of up to 3000 hours were applied. Several types of specimens - tensile. bending, and shear specimens those are transverse to the fiber direction, and bending specimens those are parallel to the tiber direction - were used to investigate the effects of environmental factors on mechanical properties of the composites. Also, glass transition temperature, storage shear modulus, loss shear modulus, and tan ${\delta}$ were measured as a function of exposure times through a dynamic mechanical analyzer. In addition. a suitable testing method for determining the effect of environmental factors on mechanical properties is suggested by comparing the results from using two different types of strain measuring sensors. Finally, composite surfaces exposed to environmental factors were examined using a scanning electron microscope.

• 대한방사선기술학회지:방사선기술과학
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• 제14권2호
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• pp.37-44
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• 1991

The combined effect of radiation and ultrasound has been studied in mouse embryos. Radiation and/or ultrasound were adminstered to ICR mice on day 8 of gestation. Intrauterine death, gross malformation, and fetal body weight were selected as indicators of effects. Does of whole-body ${\gamma}-irradiation$ were 0.5 to 2.5 Gy and those of ultrasound were $0.5\;W/cm^2$ to $3\;W/cm^2$. Intrautrine mortality increased with increasing radiation dose ; this trend was more remarkable in combination with ultrasound. Gross malformations such as exencephaly and anophthalmia/microphthalmia appeared frequently in the fetuses treated with both radiation and ultrasound. Decreased fetal weight was observed even in mice treated with 1.5 Gy of radiation or $1\;W/cm^2$ of ultrasound. There was a linear relationship between dose and reduction of fetal weight. The fetal weight was sensitive, precise and easy-to-handle indicator for the effects of growth retardation. Intrauterine mortality and frequencies of exencephaly and anophthalmia/microphthalmia were higher than the sum of those induced by radiation and by ultrasound. The results indicatied that the combined action of radiation and ultrasound on intrauterine death and malformations was synergistic.

• Structural Engineering and Mechanics
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• 제31권5호
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• pp.545-566
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• 2009

Bridge columns are subjected to combined actions of axial force, shear force and bending moment during earthquakes, caused by spatially-complex earthquake motions, features of structural configurations and the interaction between input and response characteristics. Combined actions can have significant effects on the force and deformation capacity of RC columns, resulting in unexpected large deformations and extensive damage that in turn influences the performance of bridges as vital components of transportation systems. This paper evaluates the seismic response of three prototype reinforced concrete bridges using comprehensive numerical models that are capable of simulating the complex soil-structural interaction effects and nonlinear behavior of columns. An analytical approach that can capture the shear-flexural interacting behavior is developed to model the realistic nonlinear behavior of RC columns, including the pinching behavior, strength deterioration and stiffness softening due to combined actions of shear force, axial force and bending moment. Seismic response analyses were conducted on the prototype bridges under suites of ground motions. Response quantities of bridges (e.g., drift, acceleration, section force and section moment etc.) are compared and evaluated to identify the effects of vertical motion, structural characteristics and the shear-flexural interaction on seismic demand of bridges.

• 기본간호학회지
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• 제16권1호
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• pp.64-72
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• 2009

Purpose: The objective of this study was to identify the effects of problem based learning (PBL) combined with simulation on the basic nursing competency of nursing students. Method: A pretest-posttest design with a nonequivalent control group was used to examine the effects of problem based learning combined with simulation for 9 weeks in a group of 283 nursing students. The PBL group of 141 students participated in PBL classes with simulation, 4 hours a week for 9 weeks compared to control group of 142 students who received the usual fundamental nursing class. Results: The group that had PBL with simulation showed significant increases in problem solving and self-directed learning competency, although there were no significant changes in communication competency as compared to the control group. Conclusion: The findings of this study demonstrate that PBL with simulation for nursing students may increase problem solving and self-directed learning competency and suggest that utilizing this teaching-learning method may be beneficial as an effective nursing education strategy.

• PNF and Movement
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• 제17권1호
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• pp.19-29
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• 2019

Purpose: This study was an investigation of the effects of the bridge exercise with the sensory feedback of combined abdominal drawing-in on transverse abdominal and balance in patients with stroke. Methods: Forty subjects were randomly assigned into two groups. Subjects in the bridge exercise group (BG, n = 20) or feedback drawing-in bridge exercise group (FDBG, n = 20) were studied for 30 minutes each, twice daily, for four weeks. Outcomes were measured using affected weight distribution (AWD), anterior limit of stability (ALOS), posterior limit of stability (PLOS), timed up-and-go test (TUG), the Berg balance scale (BBS), and transverse abdominis thickness (TRA) before and after the four-week intervention period. Results: There were significant effects in the FDBG pre-intervention and post-intervention in AWD, ALOS, PLOS, TUG, BBS, and TRA. Conclusion: The results of this study suggest that the bridge exercise with sensory feedback combined with abdominal drawing-in could be beneficial for patients with stroke in terms of transverse abdominal and balance.

• Steel and Composite Structures
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• 제39권4호
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• pp.419-433
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• 2021

In composite structures, shear connectors are crucial components to resist the relative slip between the steel and concrete, and thereby to achieve the composite actions. In the service stage, composite structures are usually in elastic state, so the elastic stiffness of the shear connection is a quite important parameter in the structural analysis of composite structures. Nevertheless, the existing studies mainly focus on the load-slip relationship rather than the tangent stiffness at the initial elastic stage. Furthermore, when composite beams subjected to torque or local load, shear connections are affected by both tensile force and shear force. However, the stiffness of shear connections under combined effects appears not to have been discussed hitherto. This paper investigates the initial elastic stiffness of stud connections under combined effects of biaxial forces. The initial expression and the relevant parameters are obtained by establishing a simplified analytical model of the stud connection. Afterwards, parametric finite element analysis is performed to investigate the effects of the relevant factors, including the stud length, stud diameter, elastic modulus of concrete, elastic modulus of steel and volume ratio of reinforcement. The feasibility of the proposed modelling has been proved by comparing with sufficient experimental tests. Based on the analytical analysis and the extensive numerical simulations, design equations for predicting the initial elastic stiffness of stud connections are proposed. The comparison between the equations and the data of finite element models demonstrates that the equations are accurate enough to serve for engineering communities.

• Physical Therapy Rehabilitation Science
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• 제12권3호
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• pp.355-364
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• 2023

Objective: The aim of this study is to test the effects of elastic band exercise accompanied by Swiss ball exercise on lower limb muscle strength, balance and pain in middle-aged women with osteoarthritis. Design: A randomized controlled trial. Methods: Thirty-five participants were randomly assigned to the experimental group (n=18), which performed elastic band exercise combined with Swiss ball exercise, and the control group (n=17), which performed elastic band exercise only. Both groups did a 30-minute session of exercise three times a week for eight weeks and were assessed for lower extremity muscle strength, static and dynamic balance, and pain levels before the first therapy session. All participating patients underwent outcome assessment after eight weeks of therapy without any additional treatment. Results: The experimental group made a significant increase in muscle strength of the lower extremities, static and dynamic balance ability, and pain level (p<0.05). The control group made a significant improvement in lower limb muscle strength, dynamic balance ability and pain level (p<0.05) with no such improvement in static balance ability. The exercise group made a significant increase in static and dynamic balance ability and pain level compared to the control group (p<0.05). Conclusions: These results demonstrated that both Swiss ball exercise and elastic band exercise were effective for middle-aged women with osteoarthritis and found that elastic band exercise combined with Swiss ball exercise produced more significant effects on their balance and pain.

• The Korean Journal of Pain
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• 제9권1호
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• pp.172-177
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• 1996

We performed a study of epidural patient controlled analgesia of meperidine with or without 0.08% bupivacaine for 48 hours after Cesarean section. 51 parturients were randomly assigned to one of two treatment groups : 1) epidural 0.2% meperidine group(n:24) and 2) epidural combined group with 0.2% meperidine and 0.08% bupivacaine(n:27). All parturients used patient controlled analgesia with loading dose, 2 ml/hour continuous infusion, 1 ml bolus infusion and lockout time, 8 minutes. visual analog scales after loading doses were not significantly different in either groups. The total quantity of meperidine consumption and hourly consumption were significantly lower in the combined group than meperidine group(P<0.05). The cumulative amount of meperidine consumption were also significantly lower in the combined group than meperidine group at 6, 12, 24 and 48 hours. In combined group the hourly consumption of meperidien from 3 hours to 12 hours after loading dose was significantly lower than those of meperidine group. Above 90% of parturients were satisfied in both groups. Side effects were: numbness (2), thigh weakness (1), nausea (1), headache (1) and back pain (2) in epidural meperidine group. There were no case needed specific treatment in both groups. We conclude that analgesic effects were similar in both groups, however the amount of meperidine consumption was less for meperiding group than combined group.

• 한국식품영양과학회지
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• 제46권10호
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• pp.1265-1269
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• 2017

본 연구에서는 신선 농산물의 미생물학적 안전성을 제고하기 위해 항균 효과가 있는 clove bud essential oil(CBEO)과 mild heat(MH) 처리를 병합 처리하여 Escherichia coli O157:H7이 접종된 red oak leaf의 미생물 수 변화를 측정하였다. 0.2% CBEO와 $50^{\circ}C$ MH 병합 처리구는 단순 물세척 처리구보다 1.45 log CFU/g 더 낮은 미생물 수를 나타내어 모든 병합 조건 중 가장 높은 미생물 제어 효과를 보였다. 또한, 본 병합 처리구는 비 세척 처리구와 비교하여 9일간의 저장 기간 동안 1.67~2.25 log CFU/g 더 낮은 미생물 수를 나타내어 미생물 제어 효과가 지속됨을 확인하였다. 따라서 이러한 결과들로부터 CBEO와 MH의 병합 세척 처리는 저장 중 red oak leaf와 같은 신선 농산물의 미생물학적 안전성을 확보하는 데 효과적으로 사용될 수 있다고 판단된다.

• 대한치료과학회지
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• 제10권2호
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• pp.47-57
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• 2018

Objective: The purpose of this study was to compare the effects of exercise program combined with spaced retrieval and exercise program to show the effects on elderly people with dementia by presenting them to clinics and welfare facilities such as long-term care facilities. Method: This study was conducted in 20 elderly patients with dementia and randomly assigned to exercise program combined with spaced retrieval and exercise program. After screening the subjects for compliance with the criteria, Before starting the experiment, activites of daily living, depression, and nitive evaluation were performed. After 8 weeks, 3 times per week, 40 minutes per intervention, and 4 and 8 weeks, respectively K-MBI, GDSSF-K and MMSE-K were used to evaluate the differences between the experimental and control groups. Results: There was no statistically significant difference in the daily activities, depression, and cognitive scores between the groups of exercise program combined with spaced retrieval and exercise program group. However, there was a significant difference between the two groups after training (p<.05). Particularly, there was statistically significant difference in post-training cognitive evaluation (MMSE-K) only in the exercise program combined with spaced retrieval group (p<.05) Conclusion: This study suggests that exercise program combined with spaced retrieval is more effective in improving cognitive ability. This suggests that the exercise program combined with spaced retrieval is more effective.