• 한국가스학회지
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• 제27권1호
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• pp.38-47
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• 2023

수소연료전지 차량 충전 과정에서, 충전소에서의 공급압력과 차량 내 저장 탱크의 압력 차이에 의해 수소가 흐르게 되고 유량은 압력 차에 의존한다. 따라서 충전 과정에서 발생하는 수소의 압력강하에 대한 고려는 필수적이며 이의 분석을 통해 수소 충전 과정의 효율성을 높일 수 있다. 본 연구에서는 충전라인 중 호스, 노즐/리셉터클, 파이프, 밸브에 대하여 압력강하를 분석하였다. 호스와 파이프는 도관에서의 압력강하로, 노즐/리셉터클은 흐름 노즐 식으로, 밸브는 기체 유량 식으로 계산하였다. 또한 각 구성요소에서 발생하는 압력강하 효과를 종합 분석한 결과 전체 충전라인에서 압력강하에 가장 큰 영향을 주는 요소는 밸브에서의 압력강하임이 밝혀졌다. 이번 연구는 추후 수소 충전을 포함한 수소 유동 해석으로 수소 충전 과정의 모델 개발에 활용될 수 있을 것이다.

• 산업기술연구
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• 제19권
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• pp.343-350
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• 1999

The separation of humic acid by ultrafiltration was most influenced by pressure difference. when pressure difference increased from latm to 3atm, permeate flux increased from 40% to 60% but rejection rate reduced from 97% to 91% because of adsorption of molecules of humic acid at membrane surface. Since physical adsorption was more dominant than chemical adsorption, adsorption of membrane surface was reduced 50% when slow rate increased at same conditions.

• 기본간호학회지
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• 제7권2호
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• pp.301-315
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• 2000

The main purpose of this study was to evaluate the effect of a Rhythmical Exercise Program(REP) on physiological functions such as muscle strength, blood pressure, pulse, flexibility and body fat in the elderly. The research employed a non-equivalent control group pre-post test quasi experimental design. REP consisted of 45 minutes of dance, 3 times a week for 10 weeks. The formulated hypothesis were examined using the non-parametric statistics; Wilcoxon Signed rank sum test and Mann-Whitney test. The results are as follows; 1. The upper muscle strength and lower muscle strength of the experimental group were significantly higher than those of the control group following the REP(P<.0 5). And the Period of REP affected the muscle strength; the longer the exercise period, the stronger the muscle strength became. 2. The systolic blood pressure of the experimental group was significantly lower than that of the control group following the REP(p<.05). But there was no significant difference in the diastolic blood pressure between the experimental and control groups. The period of REP affected only systolic pressure; the longer the exercise period, the lower the systolic pressure became. 3. There was no significant difference in heart rate between the experimental and control groups, following the exercise period. 4. The flexibility of the experimental group was significantly higher than those of the control group following the REP(p<.01). And the period of REP affected flexibility; the longer the exercise period, the higher the flexibility(p<.05) became. 5. There was no significant difference of body fat between the experimental and control groups. The body fat of the experimental groups was significantly lower only 10 weeks after exercise(p<.01). Based on these results, it is suggested that rhythmical exercise program improves muscle strength, systolic pressure, and flexibility in the elderly.

• 한국의류학회지
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• 제30권1호
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• pp.20-30
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• 2006

The purposes of this study were to investigate demographic profiles between the consumer group under high time pressure(HTP) and the group under low time pressure(LTP) during the shopping, to examine the level of association between the fashion information sources and time pressure variable, to determine the difference in clothing benefits sought between HTP and LTP, and to determine the difference in purchase criteria. We distributed questionnaires to 600 women aged in 20-65. The reliable 562 questionnaires were used for a statistical analysis. Data analyses were conducted with SPSS program on t-test, cluster analysis, factor analysis, and Chi square test. We obtained the following results: There was a significant association between demographic variables such as age, occupation, education, residence area, & family cycle and time pressure variable. Fashion information sources were classified into 4 factors. HTP searched information on fashion products using more various sources than LTP did. There was also a significant difference between HTP and LTP in clothing benefit sought. Four clothing benefit factors such as trendy/social position, economic value, protection/comfort, and makeup of body shape were sought more by HTP than by LTP. In addition, HTP considered significantly more purchase criteria such as color/pattern, comfort, quality, suitability, material, sewing finishing, coordination, price, brand, easy care, and country of origin than LTP.

• 한국전문물리치료학회지
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• 제17권3호
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• pp.1-10
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• 2010

The purpose of this study was to measure intra-rater and inter-rater reliability and range of motion for measurement of passive shoulder internal rotation range of motion and to compare anterior glide distance of humeral head in three methods. Fifty healthy subjects and fifty patients with shoulder musculoskeletal pain were recruited for this study. The subjects' passive shoulder internal rotation range of motion was measured by visual estimation, manual stabilization, and pressure biofeedback unit methods. In two trials, measurements were performed on each subject by two examiners. Intraclass correlation coefficient (ICC(3,1)) was used to determine the reliability of each measurement. The intra-rater reliability of the three methods was excellent (ICC=.77~.93) in both groups. The inter-rater reliability of the visual estimation method was poor (ICC=.20, .29), the manual scapular stabilization method was poor and fair (ICC=.09, .50), and the pressure biofeedback unit method was excellent (ICC .86, .75) in the experimental and control groups. In the experimental group, the difference of examined range of motion by each examiner was significant in the visual estimation method and manual scapular stabilization method, but there was an insignificant difference between the groups is the pressure biofeedback unit method. This result suggests that the intra-rater and inter-rater reliability of a pressure biofeedback unit was better than the other methods. The difference in distance of the anterior glide of humeral head was insignificant among all the methods. The pressure biofeedback unit method was the most reliable method, so it is proposed to be a new and reliable method to measure internal rotation range of motion.

• 한국운동역학회지
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• 제29권4호
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• pp.237-245
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• 2019

Objective: The purpose of this study was to investigate the effect of a 12-week Balanching Exercise on posture alignment, and foot plantar pressure balance in female middle students. Method: The subjects consisted of 26 female middle students, Among of 26 people exercise group is 13 persons (age: 14.69±0.48 yrs, height: 156.62±6.96 cm, weight: 50.72±9.94 kg) and control group is 13 persons (age: 14.85±0.38 yrs, height: 158.93±4.44 cm, weight: 54.25±6.60 kg) and they played Balanching Exercise for 12 weeks for 60 minutes a day, three times a week. Results: In this study, the changes of posture alignment of female middle students were analyzed. The results were as follows: head tilt, the shoulder tilt, the pelvis tilt in experimental group and there was statistically significant. Control group was head tilt, the shoulder tilt, the pelvis tilt but there was not statistically significant difference. The changes of foot pressure balance of female middle students were analyzed. The change of the foot pressure balance difference before and after the experimental group decreased by 29.3% from 6.69±3.86% to 4.73±3.57%, which was statistically significant. Control group was increased by 17.6% from 6.30±4.43% to 7.41±3.69% there was not statistically significant difference. Conclusion: The results of this study suggest that Balanching Exercise has a positive effect on improving the posture alignment and has a positive effect on foot pressure balance Research should be continued.

• 제어로봇시스템학회논문지
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• 제9권9호
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• pp.707-713
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• 2003

We investigate the ultrasonic gas flow meter for the measurement of gas volume quantity, which passing through pipe, using the transit time difference method. We have designed a receiving system of an ultrasonic signal and hardware system of a flow meter Also, we have designed an experimental system for the characteristic test and calibration of a gas flow meter system. We have developed an ultrasonic gas flow meter, which has a measurement uncertainty within $\pm$ 1.7 %. For the test, we have compared our system with a difference pressure type flow meter for a few months in the real field. Through the test, we have confirmed that our system have a good reliability and durability. Also, we have confirmed that our system follows very well the variation of gas volume quantity, which was measured by a difference pressure type flow meter.

• 한국세라믹학회지
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• 제34권6호
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• pp.601-610
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• 1997

In cofiring of multilayered alumina with tungsten, the change of camber with lamination condition was experimented and the effect of sintering shrinkage of alumina and tungsten was investigated. From the exact measurement of sintering shrinkage of tungsten thick film, as lamination pressure increased, the sintering shrinkage of alumina decreased but that of tungsten thick film was not changed. So it was though that the main factor which induced the sintering shrinkage difference between ceramics and metal with lamination condition was the change of sintering shrinkage of ceramics. In case of high lamination pressure, high green sheet density, the cofired specimen showed low camber due to low shrinkage difference between alumina and tungsten and there was a linear relation between camber and shrinkage difference. It was found that this shrinkage difference could change the thickness of tungsten film and the microstructure within via hole during cofiring.

• 태양에너지
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• 제8권2호
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• pp.26-38
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• 1988

If proper design and selection of the working fluid are made the power generation system of temperature difference could achieve more efficient results than others. This paper is to analysis the production of its power generation due to several parameters. Making the power generation system, the characteristics of power output are investigated to obtain its basic data for design. This results of this experiment are as follows. 1. The most proper working fluid in the system is Freon-22 having high stability and difference between the outlet pressure, $P_E$ of evaporator and outlet pressure, $P_c$ of Condenser. 2. With the increase of temperature difference between evaporator and condenser, the output in the system increases linearly. 3. The generation efficiency is largely dependent on the type or form of propeller, nozzle and optimum design of heat exchanger.

• International journal of advanced smart convergence
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• 제9권3호
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• pp.71-77
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• 2020

This study was conducted in order to determine how reductions in blood pressure during surgery affect intraoperative neuromonitoring. This retrospective study considered a total of 339 patients: 194 patients with normal neuromonitoring findings (57%), 145 (42%) with abnormal neuromonitoring findings, and 34 (10%) with postoperative neurological deficits. Comparisons between the three groups revealed that overall blood pressure during surgery, postoperative blood pressure, and the difference between the maximum and minimum blood pressure could affect the intraoperative neuromonitoring findings. While we indicate that a drop in blood pressure to below 70 mmHg could affect neuromonitoring results, differences in the dosage of anesthetic agents did not significantly affect reductions in blood pressure or neuromonitoring findings. The association of monitoring with blood pressure found in this study is expected to help future examiners. However, this study did not clarify the relationship between anesthesia and blood pressure and how it could affect intraoperative neuromonitoring. Therefore, further research on this part is thought to be necessary.