• Journal of Hydrogen and New Energy
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• v.18 no.2
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• pp.189-196
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• 2007

The evaporation heat transfer coefficient and pressure drop of $CO_2$(R-744) in a horizontal tube was investigated experimentally. The main components of the experimental apparatus are a receiver, a variable-speed pump, a mass flow meter, a pre-heater and an evaporator(test section). The test section consists of a horizontal stainless steel tube of 4.57 mm inner diameter. The experiments were conducted at mass flux of $200{\sim}1000\;kg/m^2s$ saturation temperature of $0{\sim}20^{\circ}C$, and heat flux of $10{\sim}40\;kW/m^2$. The test results showed that the heat transfer coefficient of $CO_2$ has a greater effect on nucleate boiling more than convective boiling. Mass flux of $CO_2$ does not affect nucleate boiling too much. In comparison with test data and existing correlations, All of the existing correlations for the heat transfer coefficient underestimated the experimental data. However lung et al.'s correlation showed a good agreement with the experimental data. The evaporation pressure drop of $CO_2$ increases with increasing mass flux and decreasing saturation temperature. When comparison between the experimental pressure drop and existing correlations. Existing correlations failed to predict the evaporation pressure drop of $CO_2$.

• Journal of the Korean Home Economics Association
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• v.44 no.7 s.221
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• pp.53-62
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• 2006

The purpose of this research was to evaluate the effectiveness of the Counseling-Utilized Parent Education for Mothers (CUPEM). CUPEM was developed based on Developmentally Appropriate Practices, Solution-Focused Therapy, Satir's Experiential Family Therapy, and Cognitive-Behavioral Therapy. The subjects were 51 mothers of 4 and 5 year old children and randomly assigned either to the intervention group (n=26) or the comparison group (n=25). Mothers in the intervention group had 10-2 hour intervention sessions while those in the comparison group received the intervention after this study was completed. Both groups received pre-and post-test evaluation, and a follow-up test. The data were analyzed by t-test and paired t-test. The results showed that participanting mothers' parenting stress was lessened while sense of parenting competence and positive maternal behaviors during mother-child interaction were increased significantly. Second, these mothers' self-confidence and maternal attitude toward childrearing were improved. Third, this effect lasted for at least one month after the termination of this program.

• Korean Journal of Veterinary Research
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• v.10 no.1
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• pp.47-51
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• 1970

The diagnostic effects of the Modified Whiteside Test(M.W.T.) and the California Mastitis Test(C.M.T.) for detection of bovine mastitis were studied using 372 quarter milk samples collected from six dairy herds in suburbs of Suwon city in order to compare the effectiveness of the two methods. The leucocyte count and bacteriological observation were also performed to support analysing the results. The results obtained were as follows; 1. The CMT showed more specificity than MWT for leucocytes in the abnormal milk. 2. When comparison was based on Identical ratings, agreement was obtained in 56.4% of the samples. The stronger reaction had the higher agreement and the CMT was found to be more specific than MWT in detection of the sub-clinical mastitis. 3. The CMT reaction was instantaneous and sufficiently clear-cut. 4. The results of the CMT leucocyte count and bacteriological observation were completely agreed in 69.9% of the samples. When degrees of reaction and the leucocyte count were considered, the CMT showed agreement in 93.5% of the samples.

• Proceedings of the ESK Conference
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• 1996.10a
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• pp.33-40
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• 1996

본 연구의 목적은 작업생리학적 접근방법(physiological approach)을 이용하여 생리학적 작업 능력(PWC; physiological work capacity)을 추정할 경우 작업형태와 작업방법에 따른 차이점을 비교분석해 보고자 함이다. 작업유형으로는 자전거 에르고미터(cycle ergometer)와 트레드밀 (treadmill)을 사용하였고, 작업방법으로는 각각의 작업유형에 대하여 램프 테스트(ramp test 와 인크리멘탈 테스트(increemntal test)의 차이점을 비교하였다. 또한 외국인들의 생리학적 작업능력(PWC)과 한국인들의 생리학적 작업능력(PWC)을 비교,검토하여 NIOSH(National Institute of Safety and Healty)기준치를 사용하는데 문제점이 없는가를 검토해 보고자 하였다. 작업방법 에 따른 차이점은 자전거 에르고미터의 경우 램프 테스트(ramp test )253.63 ml/min로서 인크리 멘탈 테스트(increemental test) 2859.74ml/min 의 87.70 % 정도로 나타났으며, 트레드 밑의 경우 ramp test 2859.22ml/min로서 incremental test 289.46ml/min의 98.77%정도로 나타났다. 작업유형 에 따른 결과는 자전거 에르고미터의 ramp test 트레드밀의 ramp test 는 ramp test는 트레드밀의 ramp test의 88.72% 정도로 나타났으며, 자전거 에르고미터의 incremental tests는 트레이드밀 작 업의 98.% 정도로 나타났다.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.6
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• pp.51-60
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• 2015

This study conducted shear strength test and plate bearing test to look into the characteristics of bearing capacity using geosynthetics case on forest road surface. The shear strength test showed that the internal friction angle at the time when geosynthetics was used was measured larger on average than that in the unreinforced case. Therefore, using geosynthetics case produced more bearing capacity reinforcement effect. The result from the comparison test of internal friction angle by geosynthetics type revealed that the internal friction angle at the time when geotextile case was used was measured larger. That was attributable to the difference between the area of the total cross section of geotextile made in type of non-woven fabric and its material. Plate bearing test showed that the settlement at the time when geosynthetics was used was measured smaller than that in the unreinforced case. Therefore, using geosynthetics produced more bearing power reinforcement effect. The result from the comparison test showed that geogrid case was measured smaller than geotextile case. Henceforth, It is seemed that it will be necessary to keep studying the reinforcement engineering and process of forest road surface which fits the characteristics and conditions of geosynthetics to prevent forest road demage.

• Korean Journal of Materials Research
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• v.24 no.2
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• pp.87-92
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• 2014

The Notched Ring Test(NRT) has proven to be very useful in determining the slow crack growth behavior of polyethylene pressure pipes. In particular, the test is simple and an order of magnitude shorter in experimental times as compared to the currently used Notched Pipe Test(NPT), which makes this method attractive for use as the accelerated slow crack growth test. In addition, since the NRT specimen is taken directly from the pipe, having maintained the cross-section, processing induced artifacts that would affect the slow crack growth behavior are not altered. This makes the direct comparison to the slow crack growth specimen in pipe from more meaningful. In this study, for comparison with other available slow crack growth methods, including the NPT, the stress intensity factor equation for NRT specimen was developed and demonstrated of its accuracy within 3% of that obtained from the finite element analysis. The equation was derived using a flexure formula of curved beam bending along with numerically determined geometric factors. The accuracy of the equation was successfully tested on 63, 110, 140, 160, 250, and 400 mm nominal pipe diameters, with crack depth ranging from 15 % to 45 % of the pipe wall thickness, and for standard dimensional ratio(SDR) of 9, 11, and 13.6. Using this equation the slow crack results from 110SDR11 NRT specimen were compared to that from the NPT specimen, which demonstrated that the NRT specimen was equivalent to the NPT specimen in creating the slow crack, however in much shorter experimental times.

• Journal of the Earthquake Engineering Society of Korea
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• v.1 no.4
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• pp.45-58
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• 1997

This paper describes a series of shaking table and pseudodynamic tests for evaluation of seismic performance of base-isolated structures subjected to various seismic earthquake inputs. The main objectives of this study are : (1) evaluation of the effectiveness of base-isolation systems for low-rise structures against severe seismic loads through shaking table tests, (2) verification of the substructuring pseudodynamic test method for the base-isolated structures in comparison with the shaking table test results. In the shaking table test, a quarter scaled three-story structure base-isolated by laminated rubber bearings is tested. In the pseudodynamic test, only the laminated rubber bearing s are tested using the substructuring technique, while the concurrent seismic responses of the superstructure are computed using on-line numerical integration. Comparison with the shaking table test results indicates that the substructuring pseudodynamic test method is very effective for determining the dynamic responses of the base-isolated structure.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.2
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• pp.199-207
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• 2014

Although High-altitude electromagnetic pulse(HEMP) protection filter meets the requirements of pulsed current injection(PCI) acceptance test, the equipment under test which has low electromagnetic susceptibility level can be damaged during PCI verification test that is performed on operating condition of equipment. This paper proposed the HEMP effect analysis method using comparison of norms between residual current of HEMP filter and transient electromagnetic conducted susceptibility criteria of equipment, as an alternative method under the condition that performing PCI verification test is limited in HEMP hardened facilities. PCI acceptance test of HEMP filter, transient electromagnetic conducted susceptibility test, and PCI verification test are performed and test results are analyzed.

• Journal of Korean society of Dental Hygiene
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• v.15 no.2
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• pp.325-332
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• 2015

Objectives: The purpose of this study was to investigate tooth whitening maintenance efficacy of several dentifrices containing effective ingredients for tooth whitening. Methods: Hydroxyapatite specimens(HAPs) staining was done by using modified Stookey's methods. HAPs were treated with 2.9% hydrogen peroxide containing strip for whitening, and were shaken with several dentifrice slurry(dentifrice 1 : artificial saliva 2) for 30 minutes. The HAPs were finally dipped in staining solution for an hour. Shaking and dipping were repeated 4 times and lightness values were measured by colorimeter at each step. In clinical test, test 4 dentifrice and control dentifrice were evaluated by 21 subjects for 2 months after receiving institutional review board(IRB) approval. Organoleptic(vita shade guide) and instrumental(SHADEEYE-NCC) evaluation were performed for whiteness change of teeth. Statistical analysis was performed using repeated measures ANOVA, Tukey's post hoc test and ${\chi}^2$-test(p<0.05). Results: All dentifrices showed statistical significance in comparison with control dentifrice containing sodium fluoride and test 4 dentifrice containing sodium pyrophosphate, sodium metaphosphate, candelilla wax, and sodium fluoride showed statistical significance in comparison with other dentifrices by inhibiting staining in vitro(p<0.05). In clinical test, test 4 dentifrice showed better effects than control dentifrice in organoleptic and instrumental evaluation in tooth whitening maintenance efficacy(p<0.05). The awareness toward tooth whitening maintenance efficacy for 2 months use showed that test 4 dentifrice was much better than control dentifrice, but did not show statistically significant(p>0.05). Conclusions: Dentifrice containing sodium pyrophosphate, sodium metaphosphate, candelilla wax and sodium fluoride was more effective in keeping teeth white.

• Journal of Korean Physical Therapy Science
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• v.29 no.1
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• pp.73-86
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• 2022

Background: The purpose of this study is to investigate the effect of plantar flexor on muscle fatigue and endurance when two different sport tapes are applied. Design: Cross-sectional design. Methods: Fifty-one healthy adults were randomly assigned to dynamic taping group (n=17), kinesio taping group (n=17), and control group (n=17). The dynamic taping group used the dynamic tape. The kinesio tape group used the kinesio tape, and the control group doesn't used tape. Every group performed heel rise test and sEMG for every during pre-test and post-test. To evaluate plantar flexor endurance, the number of times was measured during the heel rise test. Results: The number of heel rises increased significantly in the post-test in dynamic taping group compared to the pre-test, and In comparison between groups, the number of heel rises significantly increased in dynamic taping group compared to kinesio taping group and control group. PEF value was significantly increased in the post-test compared to the pre-test in dynamic taping group, and there was a significant difference between the three groups according to the taping application. Conclusion: The results of this study confirmed that dynamic taping was effective in musclular fatigue and endurance on plantar flexor in healthy adults. Based on these results, it is suggested that the application of dynamic tape can be suggested as one of the intervention methods for muscle endurance and muscle fatigue.