• 제목/요약/키워드: pillars

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Lightweight and Performance of Anti-Collision Strength of Automobiles Based on Carbon Fiber Composites

  • Zhang, Hongtao
    • 한국재료학회지
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    • 제29권9호
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    • pp.525-531
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    • 2019
  • The widespread use of automobiles has greatly increased energy demand and exhaust gas pollution. In order to save energy, reduce emissions and protect the environment, making lightweights automobiles is an effective measure. In this paper, carbon fiber composites and automobile B-pillars are briefly introduced, and then the mechanical properties and impact resistance of the DC590 steel B-pillars and carbon fiber composites B-pillars are simulated by the ABAQUS finite element software. The results show that the quality of compound B-pillars is reduced by 50.76 % under the same dimensions, and the mechanical property of unit mass is significantly better than that of metal B-pillars. In the course of a collision, the kinetic energy of the two B-pillars is converted into internal energy, but the total energy remains the same; the converted internal energy of the composite B-pillars is greater, the deformation is smaller and the maximum intrusion and intrusion speed is also smaller, indicating that the anti-collision performance of the composite B-pillars is excellent. In summary, the carbon fiber composites can not only reduce the quality of the B-pillars, but also improve their anti-collision performance.

상담 장면에서의 명리의 활용에 대한 국내 연구 동향 분석 (National Research Trends Regarding Use of the Four Pillars of Destiny in the Counseling Realm)

  • 홍성규;곽희용;김종우;정선용
    • 동의신경정신과학회지
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    • 제31권4호
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    • pp.289-299
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    • 2020
  • Objectives: The aim of this study is to investigate current research trends of Four Pillars of Destiny and verify its values and potential in the counselling scene, as the Four Pillars of Destiny's territory has been expanding to counselling, medical and psychiatric realm nowadays. Methods: The studies were searched from psychotherapy to general consultation, directly or indirectly related to counseling and Four Pillars of Destiny. Twenty-one published research studies were selected for analysis. The studies were categorized into 7 groups, meta-analysis, comparison with other personality tests, user's trend analysis, utilization in job counseling, disease prediction study, utilization in treatment counseling, and use in Korean medicine. Results: The selected studies attempted to expand Four Pillars of Destiny's usage through combination with other fields such as artificial intelligence, Korean medicine, and personality test. Furthermore by analyzing Four Pillars of Destiny itself to extract its key elements in counseling, such as therapeutic counseling factors and occupational counseling factors. Conclusions: At present, there are no standard use of Four Pillars of Destiny in counseling scene, for no large-scale research has been conducted or completed on this subject. This current status quo leads this paper to end up just understanding the counseling factors and possibilities of Four Pillars of Destiny rather than its psychological theory and clinical effect. However, this research trend analysis will be helpful in preparing future studies investigating Four Pillars of Destiny's counseling effect, application in the counseling scene and its psychological theory. Also, further studies, including confirmation of the theory through the operational definition, prospective research, control study, statistical technique are required in order to evaluate Four Pillars of Destiny's psychological theory and its effects to verify its use in clinical scenes.

Failure pattern of large-scale goaf collapse and a controlled roof caving method used in gypsum mine

  • Chen, Lu;Zhou, Zilong;Zang, Chuanwei;Zeng, Ling;Zhao, Yuan
    • Geomechanics and Engineering
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    • 제18권4호
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    • pp.449-457
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    • 2019
  • Physical model tests were first performed to investigate the failure pattern of multiple pillar-roof support system. It was observed in the physical model tests, pillars were design with the same mechanical parameters in model #1, cracking occurred simultaneously in panel pillars and the roof above barrier pillars. When pillars 2 to 5 lost bearing capacity, collapse of the roof supported by those pillars occurred. Physical model #2 was design with a relatively weaker pillar (pillar 3) among six pillars. It was found that the whole pillar-roof system was divided into two independent systems by a roof crack, and two pillars collapse and roof subsidence events occurred during the loading process, the first failure event was induced by the pillars failure, and the second was caused by the roof crack. Then, for a multiple pillar-roof support system, three types of failure patterns were analysed based on the condition of pillar and roof. It can be concluded that any failure of a bearing component would cause a subsidence event. However, the barrier pillar could bear the transferred load during the stress redistribution process, mitigating the propagation of collapse or cutting the roof to insulate the collapse area. Importantly, some effective methods were suggested to decrease the risk of catastrophic collapse, and the deep-hole-blasting was employed to improve the stability of the pillar and roof support system in a room and pillar mine.

Post-pillars design for safe exploitation at Trepça hard rock mine (Kosovo) based on numerical modeling

  • Ibishi, Gzim;Genis, Melih;Yavuz, Mahmut
    • Geomechanics and Engineering
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    • 제28권5호
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    • pp.463-475
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    • 2022
  • In the mine exploitation stage; one of the critical issues is the stability assessment of post-pillars. The instability of post-pillars leads to serious safety hazards in mining operations. The focus of this study is to assess the stability of post-pillars in the 130# stope in the central ore body at Trepça hard rock mine by employing both conventional (i.e., critical span curve) and numerical methods (i.e., FLAC3D). Moreover, a new numerical based index (i.e., Pillar Yield Ratio-PYR) was proposed. The aim of PYR index is to determine a border line between stable, potentially unstable, and failure state of post-pillars at a specific mine site. The critical value of pillar width to height ratio is 2.5 for deep production stopes (e.g., > 800 m). Results showed that pillar size, mining height and mining depth significantly have affected the post-pillar stability. The reliability of numerical based index (i.e., PYR) is verified based on empirical underground pillar stability graph developed by Lunder, 1994. The proposed pillar yield ratio index and pillar stability graph can be used as a design tool in new mining areas at Trepça hard rock mine and for other situations with similar geotechnical conditions.

N 버퍽층을 갖는 수퍼접합 LDMOS (Super Junction LDMOS with N-Buffer Layer)

  • 박일용
    • 대한전기학회논문지:전기물성ㆍ응용부문C
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    • 제55권2호
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    • pp.72-75
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    • 2006
  • A CMOS compatible Super Junction LDMOS (SJ-LDMOS) structure, which reduces substrate-assisted depletion effects, is reported. The proposed structure uses a N-buffer layer between the pillars and P-substrate to achieve global charge balance between the pillars, the N-buffer layer and the P-substrate. The new structure features high breakdown voltage, low on-resistance, and reduced sensitivity to doping imbalance in the pillars.

PMMA 나노 기둥의 압축시험에 대한 분자동역학 해석 (Molecular Dynamics Simulation for Compression Test of PMMA Nano Pillars)

  • 김정엽;김재현;최병익
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2007년도 춘계학술대회A
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    • pp.502-505
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    • 2007
  • PMMA has been extensively adopted in Nano Imprint Lithography(NIL). PMMA nano-structures experience severe mechanical load and deformation during NIL process, and understanding its mechanical behavior is very important in designing and optimizing NIL process. One of the most promising techniques for characterizing the mechanical behavior of nano structures is nano pillar compression test. In this study, the mechanical behaviors of PMMA pillars during compression test are analyzed using Molecular Dynamics. Two methods for simulation of PMMA nano pillars are proposed. The stress-strain relationship of nano-scale PMMA structure is obtained based on CVFF(Covalent Valence Force Fields) potential and the dependency of the applied strain rate on the stress-strain relationship is analyzed. The obtained stress-strain relationships can be useful in simulating nano-scale PMMA structures using Finite Element Method(FEM) and understanding the experimental results obtained by compression test of PMMA nano pillars.

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Molecular Dynamics Simulation Study on the Wetting Behavior of a Graphite Surface Textured with Nanopillars

  • Saha, Joyanta K.;Matin, Mohammad A.;Jang, Jihye;Jang, Joonkyung
    • Bulletin of the Korean Chemical Society
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    • 제34권4호
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    • pp.1047-1050
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    • 2013
  • Molecular dynamic simulations were performed to examine the wetting behavior of a graphite surface textured with nanoscale pillars. The contact angle of a water droplet on parallelepiped or dome-shaped pillars was investigated by systematically varying the height and width of the pillar and the spacing between pillars. An optimal inter-pillar spacing that gives the highest contact angle was found. The droplet on the dome-covered surface was determined to be more mobile than that on the surface covered with parallelepiped pillars.

고려(高麗) 금동탑(金銅塔)을 통해 본 법주사(法主寺) 팔상전(捌相殿)의 구조형식계통(構造形式系統) (The Structural Lineage of Palsangjeon in Pubjoo Temple Analyzed through Gilt-bronze Pagoda in the Koryo Period)

  • 김경표
    • 건축역사연구
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    • 제14권1호
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    • pp.89-105
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    • 2005
  • The central aim of this thesis is to see if the structure of Palsangjeon(捌相殿) in Pubjoo Temple(法住寺), a five sto wooden pagoda in Chosen(朝鮮) Dynasty, was handed down from the ancient and middle ages. This study was performed through an analysis of Gilt-Bronze Pagoda built in Koryo(高麗) period. In other words, it is aimed at analyzing which lineage the structure of Palsangjeonbelongs to as a wooden pagoda. In analyzing the structure of Palsangjeon, I attempted to find out its source from the remains of Koryo period prior to the Chosen Dynasty. Examples are the Gilt-Bronze Pagoda, built during the Koryo period. I have also examined its relationship with other existing wooden pagodas and remains. The analysis of Palsangjeon, a five story wooden pagoda in Chosen Dynasty, focuses on the following: First, I explored the possibilities of whether the structure of Palsangjeon was newly invented in Chosen Dynasty, or if it had been derived from the wooden pagodas in the Koryo period. Secondly, I tried to find out if the stable vertical planes, with a great successive diminution ratio, were derived from the middle age, i.e. Koryo period. The results of the study of Palsangjeon through Gilt-Bronze Pagoda analysis are as follows: 1. The structure of Gilt-Bronze Pagoda, a wooden pagoda from the Koryo period, is roughly classified into the accumulation type, using pipe pillars, and the one story type using whole pillars. In the accumulation type, stories are connected in either a flat format or an intervening format. The Gilt-Bronze Pagoda is mainly composed of pipe pillars, with some whole pillars. However, the central pillar was omitted in the building structure. Generally, the upper and lower stories are connected by pipe pillars in a crutch format. All the pillars, whether they are pipe pillars or whole pillars, used Naiten(內轉) technology. The Eave supporter has the Haang type(下昻) and the Muhaang type(無下昻). In most cases, high balustrades are furnished, but few tables of high balustrades have been found. The slanting roof formats have been handed down from Paekche(百濟), Silla(新羅), or Koryo(高麗). However, the structure of the octagon is assumed to be derived from Koguryo(高句麗). The structure of the Gilt-Bronze Pagoda from the Koryo period is mainly composed of accumulated flat squares, with some spire types. intervening format, the structure of Palsangjeon used whole pillars in a half story format in which upper level side pillars are installed on the lower level tie beam. From the Bronze Pagoda from the Koryo period, we can assume that the half story format of wooden pagodas that has stable vertical planes with a great successive diminution ratio was created during the mid-Koryo period at the latest and had been idly developed by the time of the Chosen Dynasty. 3. The whole pillars in Palsangjeon are also found in Gilt-Bronze Pagodas from the Koryo period. Hence, all of the pillars in Palsangjeon seem to have been handed down from the ancient construction technology. They were also used in the construction of wooden pagodas from the Koryo period. Therefore, it is assumed that Palsangjeon was constructed using the construction technology of the Chosen Dynasty that had been developed from the wooden pagoda construction technology of the Koryo period. The stable vertical planes with a great successive diminution ratio in Palsangjeon are derived from ancient Korean wooden pagodas, which have developed into indigenous Korean wooden pagodas with fairly stable vertical planes and a great design, in the half story format of Koryo and Chosen Dynasty. Therefore, it is assumed that the structure of Palsangjeon has a systematic relationship with traditional Korean wooden pagodas and is one of the indigenous Korean wooden pagoda structures. 4. In China, the intervening format has been mainly used between stories in multi-story architecture since the ancient days. At the same time, the flat format as also used in ancient and middle ages. However, the flat format was replaced by whole pillars during the Ming(明) and Manchu(淸) Dynasties, in favor of simple and compact construction. The half-story format, in which upper level side pillars are installed on tie beams, has been found in some cases, but it doesn't seem to have been the primary construction technology. Few traces of the half-story format have been found in multi-story architecture in Japan, and it has not been used as a general construction format. By contrast, the half-story format, which seems to have been derived from the Koryo period, was used as a general construction format in multi-story architecture of the Chosen Dynasty. The construction technology of multi-story architecture is related to that of multi-story wooden pagodas, but they have different production technologies. It seems that the structure of Palsangjeon did not just adopt the construction technology of multi-story architecture in the Chosen Dynasty, but it was developed from wooden pagodas in the Koryo period, including the Gilt-Bronze Pagoda. 5. Since the ancient days, most Chinese and Japanese wooden pagodas have adopted an accumulation type of structure using pipe pillars, with accumulated pointed towers. On the other hand, though most Korean wooden pagodas have also adopted an accumulation type of structure from the ancientdays, one story type using whole pillars was created in the Koryo and Chosen Dynasties. The wooden pagoda structure of Palsangjeon, with stable vertical planes in a half story format, is a unique Korean construction technology, different from the construction technologies of Chinese and Japanese wooden pagodas. This thesis clearly determined the structural characteristics of Palsangjeon. However, various remains have yet to be analyzed in depth, to establish an accurate construction technology system. In the beginning of this thesis, I had difficulty in precisely interpreting the internal structure of the Gilt-Bronze Pagoda from its appearance. However, in the process of study, the more serious problem was that there are few remains or ruins of multi-story architecture in ancient and the middle ages of Korea. Therefore, it is urgent to discover various remains in the future. This thesis succeeded in determining the structural characteristics of Palsangjeon. However, it fell short of clarifying the structural lineage of the stable vertical planes, although they show indigenous Korean architectural taste, representing the unique national emotion, and the construction format of multi-story wooden pagodas in Korea. I hope this is clarified in the future research.

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고려대장경 경판전 기둥의 재질 (Wood Quality of Column in Storage Halls of Tripitaka Koreana Woodblock)

  • 박상진;정기호;김재우
    • Journal of the Korean Wood Science and Technology
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    • 제27권1호
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    • pp.1-8
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    • 1999
  • 해인사 고려대장경판을 보관하고 있는 건물 기둥 108개의 수종을 분석한 결과는 다음과 같다. 중첩기둥 6개를 포함한 114개의 기둥 중 느티나무가 73개 64%, 잣나무가 17개 14.9%, 소나무 16개 14%, 전나무가 5개 4.4%, 상수리나무류가 2개 1.8%, 리기다소나무가 1개 0.9%의 순이다. 수다라장에는 여러 가지 수종이 검출되었으나 법보전은 48개 기둥 충 47개가 느티나무이었다. 검출된 수종의 특성으로 불 때 법보전은 적어도 고려중 후기 이전에 건조된 것으로 추정되며 다음이 수다라장, 동 서사간장은 이 보다도 훨씬 후대에 건조된 것으로 생각된다.

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경복궁 근정전 목부재의 수종분석 (Species Identification of Wood Members in the Keunjeongjeon Hall of Kyungbok Palace)

  • 박원규;김세종
    • Journal of the Korean Wood Science and Technology
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    • 제32권1호
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    • pp.88-95
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    • 2004
  • 경복궁의 정전 건물인 근정전에 쓰인 목재의 수종을 식별하기 위하여 기둥, 보, 도리, 창방, 박공 등 총 144점에 대하여 조사한 결과, 소나무와 전나무 두 수종이 식별되었다. 기둥은 1층의 경우 평주 20개 중 11개가 전나무, 9개가 소나무, 내진고주는 12개 중 7개가 전나무, 5개가 소나무, 그리고 귀고주는 3개가 전나무, 1개가 소나무로 식별되어 소나무보다 전나무가 차지하는 비율이 더 높았다. 2층 기둥 16개는 모두 소나무로 구성되어 있었다. 기둥 이외의 다른 부재는 총 92개 중 도리 2개만이 전나무였고, 나머지는 모두 소나무였다. 우리나라 궁궐의 목재가 소나무로 만들어졌다는 통설은 사실과 다르며 재료 수급에 따라 다른 수종도 사용되었음이 밝혀졌다. 조선말 소나무 장대재(長大材)가 고갈되어 강도가 떨어지는 전나무로 기둥을 많이 쓸 수밖에 없었던 것으로 생각된다.