• Title/Summary/Keyword: 기구학 해석

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Development of Ultrasonic Sensors for Simultaneous Measurement of Longitudinal and Shear Waves (종-횡파 동시 측정용 초음파 센서의 개발)

  • Kim, Yeon-Bo;Rho, Yong-Rae
    • Journal of Sensor Science and Technology
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    • v.8 no.1
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    • pp.1-9
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    • 1999
  • A study has been made on the fabrication of a dual mode(a longitudinal and shear mode) ultrasonic sensor using a single PZT piezoelectric ceramic element. We investigated the mechanism of the dual mode sensor that generated both of the longitudinal and the shear waves simultaneously with the single PZT element. Through the analysis of analytic wave propagation equations, all the possible crystal cuts have been examined to determine appropriate Euler transformation angles for efficient excitations of the dual modes. We studied the performance of a PZT element as a function of its rotation angle so that its efficiency is optimized to excite the two waves of equal strength. Experimental examination of the waveform on a delay line(STS303) setup confirms that the ultrasonic sensor can transmit and detect both longitudinal and shear waves simultaneously.

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Change Of the Properties and the $Cr_3C_2$ Phase by Sintering Atmospere on $Ti(C, N)-Cr_3C_2$ Ceramics ($Ti(C, N)-Cr_3C_2$, 소결체의 오결분위기에 따른 물성과 $Cr_3C_2$ 상변화)

  • 김무경;이재의
    • Korean Journal of Crystallography
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    • v.3 no.1
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    • pp.44-52
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    • 1992
  • The effect of sintering atmosphere on the final properties and phase change of Ti (C, N) Cr3c2 ceramics was investigated. In the case of sintering in vacuum and N2 atmosphere, densely packed sintered body was obtained. In Ar atmosphere, however, densification was much decreased compared to sintering in vacuum and Na. XRD analysis showed that in vacuum atmosphere Cr3c2 phase was changed to Cr7c3 Phase whereas in N2 and Ar atmosphere phase change was not occurred. That is, for vacuum sintering, the formation of defects in Ti(C, N) structure occurred through de-nitridation process, and it promotes the diffusion of C in Cr3c2 and raises the densification effects. But in the case of N2 atmosphere, densification phenomenon was considered to be due to sintering mechanism that enabled formation of free carbon and removal of oxygen by free carbon and existence of carbon in the grain boundary.

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Numerical study on the effect of the PET bottle thickness difference for blow molding process conditions (블로우 성형 공정 변수가 PET 용기의 두께 편차에 미치는 영향에 관한 수치해석 연구)

  • Kim, Jeong-soon;Kim, Jong-duck
    • 대한공업교육학회지
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    • v.34 no.2
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    • pp.321-330
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    • 2009
  • This study presents the blow molding of injection stretch-blow molding process for PET bottle. The numerical analysis of the blow molding of PET bottle is considered in this paper using CAE with a view to minimize the thickness difference. In order to determine the design parameters and processing conditions in blow molding, it is very important to establish the numerical model with physical phenomenon. In this study, a shell model with thickness has been introduced for the purpose and blow simulations with 3-type blow process condition are carried out. The simulations resulted in the thickness distribution in good agreement with the physical phenomenon. Also, from the result of numerical analysis, we appropriately predicted the thickness distribution along the PET bottle wall and Using the result of numerical analysis we apply the preform design and blow molding process condition for optimization.

A Study on Seeing Mechanism of Decoding Pictograms and International Standardization (픽토그램 읽기와 국제표준화)

  • Park, Jin-Sook
    • Archives of design research
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    • v.18 no.2 s.60
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    • pp.345-354
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    • 2005
  • From the 20th century, as international trade increases with the development of transportation and industries, a standard pictorial language to facilitate exchanges with others in different countries became necessary. However, it is not easy to have a full agreement on a standard pictorial language among different cultures. Therefore, the evaluation of standard pictograms has been the main discussion issue of the 150 since the organization's establishment in 1947. Although the 150 has a test method, 1509186, the participating countries do not follow the test because it does not reflect individual seeing mechanism for decoding pictogram which varies with his/her own experience. This study focuses on the theory of graphic symbol and seeing mechanism, and suggests what should be taken into account in the standardization process. In Chapter 2, the study investigates whether there be any cultural shock as we live in the net culture, and defines what reality is from a digital aesthetics view. What should be studied further is also presented, and a new method for revised international standard by means of analyzing seeing mechanism of decoding pictogram is suggested.

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Facilitation of Quadriceps Activation Following a Concentric Knee Flexion During Reciprocal Knee Movement: The Influence of Muscle Preloading (교차적 슬관절 굴곡-신전 시 슬관절 굴곡근의 구심성 수축에 의한 선행부하가 대퇴사두근의 활성화에 미치는 영향)

  • Jeon, Hye-Seon;Trimble, Mark H.;Brunt, Denis
    • Physical Therapy Korea
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    • v.10 no.4
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    • pp.1-15
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    • 2003
  • 본 연구는 슬관전 신전 직전에 수행된 선행 슬관절 굴곡이 슬관절 신전근의 최대 근력발생 및 근육 활성도(activation)에 미치는 영향을 알아보기 위하여 실시되었다. 16명의 정상인이 Cybex II 등속운동기구에서 3가지 다른 운동 속도($100^{\circ}/s$, $200^{\circ}/s$, $300^{\circ}/s$)와 2가지 다른 근육 활성 조건(선행부하가 없는 조건과 선행부하 조건)에서 슬관절의 최대 신전을 수행하였다. 연구대상자들에게 선행부하 없는 조건에서는 $90^{\circ}$ 슬관절 굴곡 상태에서 $0^{\circ}$까지 최대 신전을 수행하도록 하였고, 선행부하 조건에서는 구심성 슬와부 근육의 구심성 수축으로 $0^{\circ}$에서 $110^{\circ}$까지 굴곡한 후, 다시 $0^{\circ}$까지 최대 신전을 하도록 요구하였다. 종속변인으로는 내측광근과 외측광근의 최대 근전도와 최대 신전근력을 측정하였다. 실험 결과 최대 근전도와 최대 근력 모두 선행부하 조건에서 높게 나타났으며, 운동 속도가 증가함에 따라 최대 근력은 감소하는 전형적인 최대 근력-운동속도 상관법칙이 본 실험에서도 나타났다. 또한 운동속도와 전환속도 간의 간섭이 없는 것으로 나타나, 슬관절 신전근에 선행부하(preloading)를 가하는 것이 최대 근력-운동속도 상관법칙(force-velocity relation)에 영향을 미치지 못하는 것으로 해석되었다. 선행부하로 인해 증가된 최대 근력 및 근 활성도의 증가는 주로 신경촉진에 의한 것으로 해석된다.

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Numerical Investigation of Low-pollution Combustion with applying Flue Gas Recirculation in Counterflow Flames: Part I. Combustion Characteristics of Low NOx (대향류 화염에서 FGR이 적용된 저공해 연소의 수치적 해석: Part I. 저 NOx 연소특성)

  • Cho, Seo-Hee;Lee, Kee-Man
    • Journal of the Korean Institute of Gas
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    • v.23 no.6
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    • pp.8-16
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    • 2019
  • One of the methods for low-pollution combustion, flue gas recirculation(FGR) is effective to reduce nitrogen oxides and it was applied in CH4/air premixed counterflow flames to identify the change of flame characteristics and NOx mechanisms. Considering that the mole fraction of the products varied depending on the strain rates, the major products: CO2, H2O, O2 and N2 were recirculated as a diluent to reflect the actual combustion system. With the application of the FGR technique, a turning point of maximum flame temperature under certain strain rate condition was found. Furthermore as the recirculation ratio increased, the tendency of NO was changed before and after the turning point and the analysis on thermal NO and Fenimore NO production was conducted.

A study to contribute to a philosophy of nursing education in Korea (한국 간호교육의 이념 정립을 위한 기초조사)

  • Ha Y.S;Han Y.B
    • The Korean Nurse
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    • v.15 no.6 s.86
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    • pp.42-60
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    • 1976
  • 1.행동특성별 제언 1 기본 지식면 첫째, 간호원리, 법칙에 관한 지식을 갖게 한다. 둘째, 간호학의 용어, 기호, 단어 및 개념에 대한 지식을 갖게 한다. 셋째, 간호원리, 의견, 활동을 검증하고 판단하는 기준에 관한 지식을 갖게 한다. 넷째, 간호현상의 과정, 경향, 원인, 순서에 관한 지식을 갖게 한다. 다섯째, 간호문제 요구를 처리하는데 필요한 수단 형식, 체제, 용법에 관한 지식을 갖게 한다. 여섯째, 학설에 관한 지식을 갖게 한다. 일곱째, 간호학 분야에서의 특수한 문제나 현상을 다루는데 쓰이는 탐구방법에 관한 지식을 갖게 한다. 여덟째, 간호 문제나 자료의 분류에 관한 지식을 갖게 한다. 아홉째, 특수한 사실의 성질, 특징, 정확성에 관한 지식을 갖게 한다. 제언 2 이해능력면 첫째, 간호문제를 창조적으로 해결하고 연구, 발전 시킬 수 있는 능력을 기른다. 둘째 간호현상을 정확하게 추리하고 검증하여 결론을 추출하며 진술하는 능력을 기른다. 셋째, 간호문제를 해석하고 자료를 재정리, 재배열, 또한 새로운 견지에서 해설하는 능력을 기른다. 넷째, 관찰된 간호현상을 설문화 또는 도표화 하는 능력을 기른다. 제언 3 태도면 첫째, 정서적 안정감을 유지하면서 환자와의 인간 관계를 원만하게 유지할 수 있는 태도를 기른다. 둘째, 확신을 갖고 간호활동에 임하는 태도를 기른다. 셋째, 한국사회가 필요로 하는 간호원의 역할을 스스로 감지 적응하고 간호활동 개선에 이바지하는 태도를 기른다. 넷째, 약품을 신중히 다루는 태도를 기른다. 다섯째, 새로운 직을 배워 개척하고자 하는 의욕을 갖게 한다. 제언 4 기능면 첫째, 환자를 이해하고 안정시킬 수 있는 능력을 갖게 한다. 둘째, 간호를 포괄적으로 수행할 수 있는 능력을 기른다. 셋째, 간호문제를 창의적으로 처리할 수 있는 능력을 기른다. 넷째, 새로운 간호지식이나 기술에 대해서 자율적으로 연수, 학습할 수 있는 능력을 기른다. 다섯째, 간호 문제에 대한 흥미와 호기심을 갖게 한다. 여섯째, 병실기구를 과학적이고 합리적으로 관리하는 기능을 기른다. 일곱째, 의료(진료)기구를 조작할 수 있는 능력을 기른다. 제언5 비판능력면 첫째, 간호문제나 현상 방법에 있어서 그 가치를 논리적 또는 주관적 기준에 의해 자료를 평가하는 능력을 기른다. 둘째, 일반적인 이론, 학설, 표준 사실에 입각해서 자료를 평가할 수 있는 능력을 기른다. 제언 6 분석능력면 첫째, 요소 및 부분들간의 관련과 상호작용 또는 인간관계를 관찰하고 분석할 수 있는 능력을 기른다. 둘째, 복잡한 간호문제를 부문별, 요소별로 분석하는 능력을 기른다. 셋째, 자료의 형태, 구조, 형식의 특징과 조직을 분석하는 능력을 기른다. 제언 7 종합 능력면 첫째, 간호계획 절차를 창안할 수 있는 능력을 기른다. 둘째, 자기의 생각을 효율적으로 전달하는 능력을 기른다. 셋째, 특수한 간호 현상이나 기본적 명제에서 어떤 추상적 관계를 연역해 낼 수 있는 능력을 기른다. 제언 8 응용능력면 첫째, 간호문제를 해결하는데 실제로 응용 할 수 있는 교육을 시킨다. 둘째, 간호이론을 구체적인 상황에 효율적으로 응용할 수 있는 능력을 기른다. 셋째, 지역사회의 특성에 알맞은 간호기술이나 간호절차를 창안할 수 있는 능력을 기른다. 넷째, 간호방법을 모색하고 이용하는 능력을 기른다. 다섯째, 조사를 통해 합리적이고 논리적인 결론을 내릴 수 있는 능력을 기른다.

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New Government's Responsibility and Achievement in Records & Archives Management (공공기록물 관리에 있어 이명박정부의 책임과 '업적')

  • Lee, Seung-Hwi
    • The Korean Journal of Archival Studies
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    • no.18
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    • pp.257-280
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    • 2008
  • The purpose of this paper is reviewing the hot issue called 'draining away the presidential records' case occurred recently and finding the root cause why the state of affairs has been happened in Korea. Though the presidential records management law ensures the rights for the prior president to view his presidential records, the prior president has copied his presidential records produced while in office and moved to his private house at his retirement. He might have interpreted his right to his presidential records too broadly and done the 'draining away' them. There was a motive why the prior president did that at that time. The reason was because the National Archives didn't guarantee the services for right viewing the records to him who wanted to review his records from right after his retirement. The National Archives have judged the draining away the prior presidential records as illegal and accused a few public servants suspected to be responsible for the affairs. The formal accuser is the National Archives, but the actual accuser might be the current Presidential Secretariat. Whatever the results of juristic judgement are, the reason why the records management field should focus and treat this case importantly is that the collapse possibility of the protection wall needed essentially and critically to the Presidential records becomes very high. The root cause of this case might exist in the fact that the records and archives management organizations have not owned the political independence. But the National Archives has submitted the revised bill of the public records and archives management law which lower the position of the National Records Management Committee controlled under from the Prime Minister to the Ministry of Administration and Security. It might be hot concern that the records and archives management organizations have difficulty for keeping the political independence if the revision would be passed. Besides the political independence factor, the most important factor needed for the right records management is the establishing the professional specificity of records management. The specific action for the establishing professional specificity would be employing of specialists and introducing the open official appointment. But it was found from the reorganization after the governmental change that the professional specificity of the National Archives have been reduced. Although the policies introduced by the new government are worrying, it might be an inheritance from the prior government. If new government would build establish the institution for the political independence of the records and archives management organizations and expand the employment of the records management professions to the local government, these affairs can be not only the responsibilities but also the achievements of the new government.

A Study on the Qualifications of Designated Person on the Maritime Safety Act (해사안전법상 안전관리책임자 및 안전관리자의 자격요건에 관한 연구)

  • Jin, Ho-Hyun;Kim, Jin-Kwon
    • Journal of Navigation and Port Research
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    • v.37 no.5
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    • pp.519-526
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    • 2013
  • In managing shipping business, the concept of seaworthiness of the vessel has developed in accordance with the development of the shipping industry. However, despite of the development of the vessel's seaworthiness, marine accident has continuously occurred at sea. International Maritime Organization(IMO) has paid attention to the research and investigation of Human Error in shipping operations in addition to physical seaworthiness of the vessel. In 1994, IMO adopted the "International Management Code for the Safe Operation of Ships and for Pollution Prevention(ISM code)" of "SOLAS 1974" Annex, to take countermeasure against this human error. In 1999, Korea adopted the 'ISM Code' and then enacted the Maritime Safety Act (previously Maritime Traffic Safety Act). The Maritime Safety Act regulates necessary qualifications of the Human Resources of shipping companies for establishment and implementation of the safety management system. However, there has been a discrepancy between shipowners and ship management companies in interpreting the legislative texts, finally causing confusion. In this paper, I would like to examine the deficiencies in the regulation on the standard of qualifications of the Designated Person under the Maritime Safety Act and thereby suggest any possible improvements in it.

Diurnal and Seasonal Variation of Chlorophyll Fluorescence from Korean Fir Plants on Mt. Halla (한라산 구상나무 잎의 엽록소형광의 일변화와 계절적 변화)

  • 오순자;고정군;김응식;오문유;고석찬
    • Korean Journal of Environmental Biology
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    • v.19 no.1
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    • pp.43-48
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    • 2001
  • Chlorophyll fluorescence of needles of Korean fir (Abies koreana) plants and environmental factors of their natural habitat were investigated in order to obtain the information for environmental adaptation and conservation of Korean fir plants. The photochemical efficiency of photosystem II, Fv/Fm, of Korean fir needles was significantly low (0.19-0.36) in the winter, whereas it was high (0.8-0.86) in the summer. The Fv/Fm value of the winter was slightly higher at mid-day than at dawn, suggesting that mid-day environmental conditions of the winter were favorable on needles of Korean fir plants. In contrast, the mid-day Fv/Fm value of the summer maintained high (around 0.8). It indicates that mid-day environmental conditions of the summer did not induce photodamage, although it caused a slight decrease in the Fv/Fm values. The non-photochemical fluorescence quenching (NPQ) of Korean fir needles was very low (0-0.01) all through the day in the winter. However, it was high (0.76) at mid-day in the summer. These results suggest that Korean fir plants have a system for the protection of PS II from mid-day environmental stresses of the summer. In the winter, the Fv/Fm values were positively correlated with temperature, light intensity and relative humidity, although NPQ values showed no correlation with any of them. In the summer, the Fv/Fm values were positively correlated with relative humidity but negatively correlated with temperature and light intensity. These results indicate that increase of tempera-ture, light intensity and relative humidity lead to promotion of the photochemical efficiency in the winter and high temperature and light intensity may cause photoinhibition in the summer.

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