• Title/Summary/Keyword: Experimental Result

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고온 고압 환경에서 가변추력기용 핀틀의 열전달 계수에 대한 수치적 연구 및 2D 실험 (Numerical Analysis and 2-D Experiment of Heat Transfer Coefficient on the Pintle of a Controllable Thruster Nozzle)

  • 박순상;문영기;곽재수
    • 항공우주시스템공학회지
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    • 제6권4호
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    • pp.24-28
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    • 2012
  • In this paper, 2-D experiment and steady-state computational fluid analysis were conducted for measuring the hear transfer coefficient of pintle type controllable thruster in high pressure and temperature. In case of 2-D experiment, transient liquid crystal technique was used for measuring heat transfer coefficient for the 2-D pintle model. The experimental result was used to validate the CFD result. The CFD results well predicted the heat transfer coefficient on the pintle surface except the nozzle downstream region, where the results by CFD was higher than experimental results. The CFD results were also compared with the result by Bartz equation and the it was shown that the Bartz equation overestimated the heat transfer coefficient on the nozzle throat as much as 80%.

마이크로프로세서 기반 인터럽트 제어방법에 의한 키보드 스캔 알고리즘에 관한 실험적 연구 (Experimental Study on the Keyboard Scanned Algorithm by a Microprocessor-Based Interrupt Control Method)

  • 이영욱
    • 한국콘텐츠학회:학술대회논문집
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    • 한국콘텐츠학회 2010년도 춘계 종합학술대회 논문집
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    • pp.272-273
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    • 2010
  • 마이크로프로세서 시스템의 키보드 버튼의 누름 결과를 기존의 입력 스캔 제어방법이 아닌 인터럽트 제어방법으로 시도하였다. 키보드 스캔 결과를 인터럽트 제어 방법으로 제어 시 적절한 30ms의 주기로 인식하도록 함으로써 마이크로프로세서의 작업부하를 줄이는 키보드 버튼 누름 제어 인식 알고리즘을 제시하였다.

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The Practical Method and Experimental Verification of Temperature Estimation in the Permanent Magnet of Electric Machine

  • Kang, Kyongho;Yu, Sukjin;Lee, Geunho;Lee, Byeong-Hwa
    • Journal of Magnetics
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    • 제20권4호
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    • pp.421-426
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    • 2015
  • This paper presents a practical method for estimation of average temperature in the permanent magnet (PM) of electric machine by using finite element analysis (FEA) and dynamo load experiment. First of all, the temperature effect of PM to the torque has been employed by FEA in order to evaluate the Temperature-Torque characteristic curve. The 1st order polynomial equation which is torque attenuation coefficient is derived by the FEA result of the Temperature-Torque curve. Next, torque saturation test with constant current condition is performed by dynamo load experiment. Then, the temperature trend can be estimated by adding the initial starting temperature using the torque attenuation coefficient and torque saturation curve. Lastly, estimated temperature is validated by infrared thermometer which measures temperature of PM surface. The comparison between the estimated result and experimental result gives a good agreement within a deviation of maximum $8^{\circ}C$.

PSC보의 긴장력이 고유진동수에 미치는 영향 (Effect of prestressing force on natural frequency of a prestressed concrete beam)

  • 최상현
    • 한국재난정보학회 논문집
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    • 제5권2호
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    • pp.124-137
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    • 2009
  • The research on the effect of the prestressing force on the frequency of PSC(Prestressed Concrete beam) has been conducted theoretically and experimentally, and a few theory has been presented. However, the presented theories show no agreement in predicting the effect of the prestressing force. In this paper, the theories on the effect of the prestressing force on the frequency of PSC beam are presented and evaluated using the experimental result. To obtain the experimental result, two PSC beam specimens were manufactured, and the modal test and analysis were performed. The modal analysis results revealed that the prestressing force increased the natural frequency of the PSC beam. Comparing predicted results using existing theories show that Kim's model, which substitutes the prestressing tendon with the equivalent beam, gives the best prediction result.

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비 Froude수에 있어서 선체의 조파저항 (Wave Resistance of a Ship at Low Froude Numbers)

  • 김인철
    • 수산해양기술연구
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    • 제17권2호
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    • pp.109-113
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    • 1981
  • Most existing theories on ship waves and wave resistance are based on the perturbation of the flow field by a small pararr.eter which specifies the slenderness of the ship hull. Since however, ship hulls in practice are neither so slender nor thin enough to secure the validity of the linearized theory, the agreen:ent between the theoretical prediction and the experimental result is not generally satisfactory. The author pointed out that the contribution by the non-linear term in the free surface condition can be represented by sorr.e source distribution over the still water plane. This paper leads to a forrr.ula for the wave resistance of not slender ships at low Froude nurr.bers. and deals with the asynptotic expression. As a nurr.erical example, the wave resistance of Wigley model is calculated, and the result is compared with experimental values. It is concluded that the wave resistance coefficient varies in the rate of Fn6 at low speed limit in general. A comparison with the result derived from the linearized free surface condition shows that the non-linearity of the free surface is irr portant at low speed.

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파괴에너지를 고려한 유사취성재료의 혼합모드 균열해석 (Mixed-Mode Fracture Analysis of Quasi-Brittle Material Considering Fracture Energy)

  • 임윤묵;김문겸;조석호;신승교
    • 한국구조물진단유지관리공학회 논문집
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    • 제6권4호
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    • pp.129-137
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    • 2002
  • In this study, mixed-mode fracture behavior is simulated effectively through the numerical method using the axial defomation link elements which can predict the behavior of quasi-brittle material. The behavior of quasi-brittle material is modeled numerically using the exponential tension softening constitutive equation and verified by comparing with the result of published experimental result. In order to verify the mixed-mode fracture behavior through the developed numerical method, analysis of mode I is formulated and the result is compared with those of FEM first, and then mixed-mode analysis is analyzed and compared with existing theories and experimental data. Also the characteristics of fracture behavior is examined through the analysis of crack generation with respect to various mode mixity.

편백 정유향의 흡입이 주의집중력과 기분상태의 변화에 미치는 영향 (Effects of Inhalation of Wood Essential Oil (Chamaecyparis obtusa) on the Change of Concentration and Mood States)

  • 성현수;고유라;최인화
    • Journal of Forest and Environmental Science
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    • 제30권1호
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    • pp.62-70
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    • 2014
  • The principle purpose of this research is to figure out whether the inhalation of Wood Essential oil (Chamaecyparis obtusa) affect not only human beings' concentration for surroundings but also change as to status of feelings. total number of subjects for this experimental are determined to be 66 (men 44 and women 22) among 85 adults who agreed to participate in this experiment after excluding 19 participants who were not able to smell scent due to flu and nasal inflammation. After both experimental group and control group being measured referring to their status of mood such as concentration, depression, vigor, fatigue, confusion, tension and anger, the experimental group is offered to get a piece of cotton that includes Wood Essential oil and they are asked to inhale it for 5 min. On the other hand, control group is offered to wait for the experimental group finishing inhaling wood Essential oil for 5 min. After 5 min, the status of mood from both groups were measured again. simultaneously, I conducted a survey targeting experimental group to see what their preferences are like regarding scent of wood essential oil. The experiment shows that the status of experimental group's concentration is improved about 0.94 point when compared to control group's. Moreover, Total mood disturbance is lower than control group's. Therefore it is proved that the inhalation of wood Essential oil alleviates overall status of mood. according to the analyses result of favor to scent for wood essential oil from experimental group, some of them who were positive got much better improvement when it comes to concentration and far more relieved on their feelings than those who weren't. Based from this result, it is definitely confirmed that there is a Phytoncide's psychophysiological effect which transcends the Placebo Effect generated by Phytoncide's positive image.

수술전 간호정보 제공이 복부수술환자의 자가간호 수행에 미치는 영향 (A Study on the Effect of Preoperative Nursing Informations on the Self-Care in Abdominal Surgery Patients.)

  • 박덕순;권영숙;박청자
    • 기본간호학회지
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    • 제6권3호
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    • pp.583-596
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    • 1999
  • The purpose of this study was to examine the effect of self-care of abdominal surgery patients in surgical intensive care unit after offering preoperative nursing information. This study worked out nonequivalant control group post test only design as suspected experimental study. This subjects of the study were 45 patients, 23 in experimental group and 22 in control group. This study was carried at a university hospital in Taegu between January 12, 1999 and March 13, 1999. The experimental group was supplied with preoperative nursing information and the control group received routine care in ICU. The measuring tools of this study were assessment of the self-care role behavior. The data were analyzed by SPSS computer program, $x^2-test$ and t-test and ANOVA were utilized for testing the difference between the experimental and the control group. The hypothesis was examined by t-test. The result of this study are summarized as follows ; 1) The hypothesis, 'The experimental group will show a higher level of self-care than the control group' was accepted(t=-8.958, p=.000). 2) We could not find any meaningful relation about general characteristics and disease associated characteristics between the experimental and the control group. 3) The self-care behavior scores according to the general characteristics and disease associated characteristics show significant statistical difference by economics status (p=.033). 4) The rate of self-care behavior scores of each questionnaire are below average in the questions that request active activity to prevent postoperative complications From the result of this study, the self-care of the experimental group was higher than those of the control group, and the nursing information can be regarded as an effective nursing intervention for preoperative patients.

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감각운동 훈련을 병행한 순환식 과제 지향 운동프로그램이 뇌졸중 환자의 보행 및 균형에 미치는 영향 : 예비연구 (The Effects of Task-Related Circuit Exercise Program Combined with Sensorimotor Training on Balance and Walking in Persons with Stroke : A pilot study)

  • 김선민;강순희
    • 대한통합의학회지
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    • 제4권4호
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    • pp.21-32
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    • 2016
  • Purpose: The purpose of this study was to identify whether task-related circuit exercise program combined with sensorimotor training for 4 weeks could improve the balance and gait in stroke patients. Method: Fifteen stroke patients who had agreed with the study were randomly divided into 3 groups categorized as task-related circuit exercise program combined with sensorimotor training group (experimental group 1, n=5), task-related circuit exercise program group (experimental group 2, n=5), and control subjects performed conventional physical therapy (control group, n=5). The balance and gait were assessed by BT-4 force platform system, Berg Balance Scale, 10meter Walk Test and Smart Step at before training and after training. Wilcoxon signed rank test was used to analyze change before and after intervention in intra-group. Kruskal Wallis H test, Mann-Whitney U test and Bonfferoni correction were used to analyze changes of all variables in inter-groups. Result: The experimental group 1 showed significant improvements in postural sway area, BBS scores, walking velocity and plantar pressures of affected foot, whereas the experimental group 2 showed significant improvements in BBS scores, and the control group were no significantly different in all variables following training. The changes of postural sway area and BBS scores in the experimental group 1 were significantly greater than them of the control group. The changes of postural sway area in the experimental group 1 was significantly greater than that of the experimental group 2. Conclusion: The result of this study suggest the task-related circuit exercise program combined with sensorimotor training is an effective intervention to improve balance and gait in stoke patients.

SOI 프로그램이 아동의 지능 및 사고력 개발에 미치는 영향 (A Study on the Effects of Structure of Intellect(SOI) Program on the Intelligence and Thinking Abilities)

  • 이기우
    • 영재교육연구
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    • 제7권1호
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    • pp.51-76
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    • 1997
  • The purpose of this study was to investigate the effects of Structure of Intellect( SOI) program for children. To achieve this purpose, 81 second grade children were sampled in a elementary school located In Seoul-city and randomly assigned to the experimental group and control group The SO1 training program were treated to the experimental group for 10 weeks, and the 'Thinking Abilities Test developed by Korea Creativity Research Institute were administered to them for pre-test and post-test. The collected data were analyzed by t-test for comparing the group means of experimental group and control group 'I'he results of this study were as follows : Firstly ere were statistically significant differences between experimental group and control group on the post-test scores of arithmetic[t(79)=2.73p,< .01] and visual memory[t(79)-3.68,p <.001]. The mean scores of experimental group(M=8.63) u ere higher than that of control group(Mz7.34) on arithmetic, and the mean scores to experimental group(M=16.68) were higher than that of control group(M=15 32) on visual memory Secondly there were no statistically significant differences between experimental group and control group on the post-test scores of logistic thinking abilities[t(79)=0.22, p>.05] and abstract thinking abilities[t(79)-0.22, p>.051. Thirdly, the post-test scores of visual memory and logical thinking abilities were more increased in the low intelligence group than the high intelligence group. This result showed that the SO1 program were more effective for the low intelligence group. Fourthly, the post-test scores of visual memory and logical thinking abilities were more increased in the low achievement group than the high achievement group. This result showed that the SO1 program were more effective for the low achievement group.

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