• 제목/요약/키워드: 1st Frequency

검색결과 943건 처리시간 0.03초

Co-rotational Shell 요소를 이용한 모터사이클 후방프레임 구조 해석 및 설계변수해석 (Structural and Parametric Analysis for a Motorcycle Rear Frame using Co-rotational Shell Elements)

  • 염제완;강승훈;신상준
    • 한국전산구조공학회논문집
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    • 제33권4호
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    • pp.209-216
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    • 2020
  • 본 논문에서는 CR 쉘 요소 해석 기법을 활용하여 모터사이클 후방프레임의 해석을 수행하였다. CR 쉘 요소 해석기법은 적은 요소수에서 NASTRAN보다 빠르게 수렴하는 결과를 보여주었다. 후방프레임은 수직 방향에 대해 실 주행 조건 시 엔진 RPM과 근접한 고유진동수를 가짐을 보여주었다. 2가지 설계변수를 반영한 세 가지 경우에 대한 해석이 제시되었으며, 보강용 자재는 동일한 중량 변화 내에서 두께 변화에 비해 더 유용한 수단임을 확인할 수 있었다. 본 연구의 구조 해석은 차후 모터사이클 후방프레임의 내구성을 향상하는 설계 개선 연구에 효과적으로 활용될 수 있다.

초기 양식건축물의 보수.보존에 관한 연구 -국가 지정 교회건축 문화재의 현황조사를 중심으로- (A Study on Repairing and Preservation of the Early Western Style Architecture in Korea - Focused on the Case Study on the Church Buildings Which are Registered as National Cultural Properties -)

  • 김정신
    • 건축역사연구
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    • 제10권2호
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    • pp.55-71
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    • 2001
  • This study reviewed the preservation status of the Early Western Style Architecture in Korea based on the on-site research of church buildings which are registered as National Cultural Properties. I have investigated 21 church buildings regarding the frequency, content and concept of restoration. The results are summarized as follows First, the churches have been restored extensively in every 17 years on the average. Second, the main restorations are replacement of bricks, painting, waterproofing, repair of roof and timber. And the main changes are extension of plan, removal of Interior posts, and replacement of floor. Third, the main concept of restorations are historical restoration(62%), critical restoration(23%), stylistic restoration(14%). Forth, the category of restoration have been changed, that is extending of incompletion (1st stage), functional improvement and extension of the span of life(2nd stage), improvement of facilities(3rd stage), restoration to the original state and conservation(4th stage). Fifth, the issues of repairing techniques are revival and replacement of weathered bricks, the removal of painting, and structural reinforcement. This study will be able to be used as the fundamental materials to improve the techniques of restoration of Early Western style masonry buildings.

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영구임대아파트 거주자 주거지 재생 수요조사 연구 - 인천 만수주공 7단지 거주자를 중심으로 - (The Demands for Housing Regeneration of the Permanent Rental Apartment Dwellers -With Special Reference to Man-soo 7 Complex in Incheon-)

  • 김미희;박병규;노세희
    • 한국주거학회:학술대회논문집
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    • 한국주거학회 2009년 춘계학술발표대회 논문집
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    • pp.137-142
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    • 2009
  • The purpose of this study is to collect baseline data about the demands for housing regeneration of the permanent rental apartment dwellers. Self-administered questionaires and interviews were provided to 144 dwellers in Incheon Man-soo 7 complex from 2008 December 29th to 31st. The collected data was used to conduct comparative and descriptive statistical analysis: frequency, t-test, and $X^2$-test. The main findings are as follows : 1. House repairing and papering is most common used service by respondents. They also have much need for economic support. 2. Residents were satisfied with general environment of house. This survey showes that the highest satisfaction was about using food waste disposal sites. and the lowest satisfaction was about soundproof facilities on the other hand, among the questions. 3. Dwellers wanted to remodeling such as bathroom, restroom, a flower garden, space of landscape architecture. More than half dwellers preferred to leave among themselves living at permanent rental apartment as it is. 4. There is important difference in the demands of housing regeneration as the family trait. and variables of those were nuclear family or elderly/handicapped-family.

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2단계 증착 방법에 의한 ZnO 박막의 c-축 배향성 및 비저항 향상에 관한 연구 (A study on the improvement of c-axis preferred orientation and electrical resistivity of ZnO thin films by two-step deposition method)

  • 이혜정;이명호;이진복;서수형;박진석
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2001년도 하계학술대회 논문집 C
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    • pp.1340-1342
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    • 2001
  • ZnO thin films are Prepared on Si(111) substrate by RF magnetron sputtering. Two-step deposition method is proposed to obtain ZnO thin films with high c-axis (002) TC value and electrical resistivity. This method consists of the following two-step deposition procedures: 1st-deposition for 10$\sim$30 min without oxygen at 100W and 2nd-deposition with oxygen added in the range of $O_2/(Ar+O_2)$ = 10 $\sim$ 50%. SAW filters with IDT/ZnO/Si(111) configuration are also fabricated. From the frequency response characteristics, the insertion loss and the side-lobe rejection are estimated.

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임상가를 위한 특집1 - 근관치료에서의 레이저의 활용 (Lasers in Endodontics)

  • 허성윤;임은미;김선영;박상혁
    • 대한치과의사협회지
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    • 제49권11호
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    • pp.660-669
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    • 2011
  • Er: YAG laser irradiation utilizing the newly developed RCLase side-firing spiral tip was used for the cleansing of root canals following their bio-mechanical preparation with ProTaper Ni-Ti files. The distal and palatal roots of 20 freshly extracted molar teeth were instrumented to size F3 with ProTaper files. In the experimental group (10 teeth) the pulp chamber and the root canals were filled with EDTA 17% and the root canals were lased for 30 s using the Er: YAG laser irradiation at 600 mJ per pulse and a frequency of 12 Hz. In the control group (10 teeth) the root canals were not lased. Scanning electron microscope analysis showed clean wall surfaces of the lased root canals with open dentinal tubules, free of smear layer and debris. In the scanning electron microscope photographs of the walls of the non-lased root canals a considerable amount of debris could be detected. It appears that an efficient cleansing of the root canal system can be achieved by using the Er: YAG laser irradiation with the RCLase Side-firing Spiral Tip following bio-mechanical preparation of the root canal with Ni-Ti Taper files.

트윈세대의 의복 치수적합성에 관한 연구 (A Study on the Fitting Size of Tween Generation' Garments)

  • 이진희;전명숙
    • 대한가정학회지
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    • 제44권10호
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    • pp.145-154
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    • 2006
  • The purpose of this study was to examine how the garment sizes by junior brand manufactures reflect Tween Generation's (ages from 5th grade to 9th grade) actual body sizes. They have diverse clothing preferences in styles and fitting levels as well as diverse body sizes and shapes. The subjects of this study were 520 students (the 5th and 6th grades in elementary schools, the 1st, 2nd and 3rd grades in middle schools) who lived in Jeonju. A questionnaire was used in this study. The data were analyzed by frequency, means, t-test and $\chi^2$. The results were as follows. In the selection of garment size, both the girl and boy students most preferred selecting garments after trying them on by themselves. Boy students tended to select garment size according to their mothers' advice. On the other hand, elementary school students showed a tendency to select garment size with their mothers. In fitting sizes, middle school girls wanted the size to fit tightly rather than loosely on their bodies much more than elementary school girls. Junior brand manufacturers produced sizes that well reflected actual body sizes of elementary and middle school girls. Specifically, the pants best covered their body sizes.

The Effect of Workplace Noise on the Hearing Threshold of Dental Technicians

  • Lee, Ju Hee;Lee, Hye Ran;Lee, Og Kyoung
    • 대한의생명과학회지
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    • 제20권4호
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    • pp.201-208
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    • 2014
  • This study was conducted to investigate hypoacusis due to workplace noise among dental technicians. Pure tone audiometry, impedance audiometry and heart rate variability were measured for 60 dental technicians and office workers in D city from July to November 2013, and a survey on the effects of noise was conducted. SPSS 19.0 was used for statistical analysis. In the result for threshold of pure tone audiometry, the average hearing threshold of left ears in the air conduction (AC) test showed a statistically significant decrease (P=0.019) among dental technicians, who are frequently exposed to workplace noise. The hearing threshold in the AC test for each frequency was significantly different between the two groups at 125 Hz (P=0.012) in right ears and at 1 kHz (P=0.022), 2 kHz (P=0.040), and 8 kHz (P=0.018) in left ears. Dental technicians who had worked for 16 years or longer had a significantly higher incidence of hypoacusis in the right ear (P=0.030) and in the left ear (P=0.010). In impedance audiometry showed a tympanometry result of type A in both the dental technician group and the office worker group.

간섭전류자극이 말초 혈류속도에 미치는 영향 (Effects of Interferential Current Stimulation on the Peripheral Blood Velocity in Healthy Subjects)

  • 박장성;이재형
    • The Journal of Korean Physical Therapy
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    • 제11권2호
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    • pp.37-42
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    • 1999
  • The purpose of this study was to determine whether percutaneous interferential current stimulation on thoracic sympathetic ganglia with amplitude modulated frequency (AMF) $90\~100$ bps and subthreshold of muscle contraction for 10 minutes on peripheral blood flow velocity in healthy subjects. Thirty-seven healthy volunteers were assigned randomly into an experimental group (n=25) and a control group (n=12). the experimental group received interferential current stimulation with subthreshold of the muscle contraction of current at AMF $90\~100$ bps on $1st\~5th$ thoracic sympathetic ganglial region for 10 minutes. The control group received same handling and electode placement, but no current was applied. Using a Doppler blood flow meter, the radial arterial blood flow velocities and the pulse raters were determined for two-way analysis of variance for repeated measures on time and group. There were no significant difference between the two groups with respect to the changes in arterial blood flow velocity and pulse rate over the four measurement times. Interferential current stimulation did not change in mean blood flow velocity and pulse rate. We conclude that interferential current stimulation on the thoracic sympathetic ganglia, as used in this study, did not dilate peripheral artery. This results suggests that interferential current stimulation dose not alter the activtiy of sympathetic nerve.

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도심지 발파공사장의 발파진동 특성 (The Characteristics of Blasting Vibration in the Construction of Apartment and Buildings in Urban Area)

  • 이연수;장서일
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2004년도 춘계학술대회논문집
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    • pp.521-526
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    • 2004
  • In order to evaluate the effect of blasting vibration in buildings and it's resident located around blasting construction field in urban area, blasting vibration characteristics were measured the vibration level, vibration velocity. The 250g and 750g of charged powder were used at the apartment and at the ground, respectively. In the measurement of the ground, Z(perpendicularity) axis was the highest value in vibration level, but vertical axis was the highest value at 25m point and longitudinal axis was the highest value at 50m point in vibration velocity. The amount of measurement was high value when measuring point is higher than blasting source, while that of measurement was low value when measuring point is lower than blasting source. In the measurement of the apartment, 2 axis was the highest value in vibration level, but in vibration velocity transverse axis was the highest value at ground, was vertical axis at 1st floor, was longitudinal axis at 3rd floor and was vertical and longitudinal axis at 5th floor. The vibration level and the vibration velocity of 50m point showed higher correlation value than 25m point at the ground, but those of 25m point showed higher correlation value than 50m point at the apartment.

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간호대학생의 학습된 무기력과 무기력 행동 (A Study on Nursing students' Learned helplessness and Helplessness behavior)

  • 윤현경
    • 한국보건간호학회지
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    • 제29권2호
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    • pp.244-256
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    • 2015
  • Purpose: The current study is a descriptive survey study conducted in order to investigate degree and properties of learned helplessness and lethargic behaviors in students of the college of nursing. Methods: A total of 332 nursing students were enrolled and responded for data collection from October $1^{st}$ through October $20^{th}$, 2013. Frequency, percentile, means and standard deviations of collected data were analyzed using t-test, one-way ANOVA, and Pearson correlation coefficient. Results: The mean score of learned helplessness in nursing students was 2.46, which was statistically significant in relation to friendship (F=13.45, p<.001) and academic achievement (F=3.67, p<.013). On the other hand, the average score of lethargic behaviors was 2.52 and it showed significant association with grade (F=6.49, p<.001), current residence (F=3.26, p<.022), friendship (F=4.81, p<.009), and academic achievement (F=5.34, p<.001), indicating a positive association between these variables. Conclusion: Based on the study results herein, effective counseling, as well as continuous attention to students by school, and professors are needed in order to alleviate sense of learned helplessness, which is a psychological variables often shown in nursing patients. Further, additional studies with regards to various variables impacting the nursing student might be warranted.