Strain Distributions of Plane-Strained and Simple-Sheared Al–Mg Alloy

Hyeon‑Woo Son,Jae‑Cheol Lee,Hyun Soon Park,Soong‑Keun Hyun 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.11

Strain distribution in plane-strained (rolling) and simple-sheared (torsion) Al–Mg alloy has been estimated using both X-rayline profile analysis and electron backscatter technique. The strain analyses under unified texture distribution by orientationrotation showed that torsion has relatively homogeneous strain distribution regardless of texture component in contrast toinhomogeneous strain in rolling. In addition, annealing texture of torsion has more random texture than inhomogeneousrolling texture. Lower texture difference index in annealed torsion specimens suggest homogeneous strain distribution insimple shear has a higher resistance to strain-induced boundary migration, which has been known to be main reason forstrong development of ND||⟨100⟩ component during annealing of rolled Al sheet.

핸드볼 선수의 기초체력 육성방안 및 기술의 동작 요령에 대한 고찰

손현주 이화여자대학교 체육대학 1984 建美 Vol.- No.17

침수 및 온도변화에 따른 레진브라켓 Wing의 파절강도 비교

손지형,황현식 전남대학교 치과대학 2000 전남치대논문집 Vol.12 No.1

The purpose of this study was to evaluate the effect of oral environment on the strength of resin bracket wings by comparing fracture mode according to water immersion and thermal change. Seventy-five resin brackets(Spirit MB, Ormco, California) were divided into three groups and treated for six months as follows; (1) untreated, (2) water immersion in distilled water at 37℃, (3) water immersion in distilled water at 37℃ with total 2,100 times of thermocycling taken 350 times each month. Fracture mode of the wing was tested on universal testing machine. In addition to resin brackets, 25 metal brackets were used as controls. Through the statistical analyses, following results were obtained. 1. Resin bracket wings showed significantly lower fracture strength than metal brackets(p<0.001). 2. Water immersion and water immersion with thermocycling groups showed significantly lower fracture strength than open air condition group(p<0.001). 3. Water immersion with thermocycling group showed significantly lower fracture strength than water immersion group(p<0.001> The above results suggest that the mechanical property of resin bracket wing may be influenced by oral environment and further research is needed to improve the strength of the wing in the resin bracket.

뇌사에 대한 의사와 일반인의 태도 조사

손현균,김광일,김이영 大韓神經精神醫學會 1994 신경정신의학 Vol.33 No.1

In this attitude survey using Q-methodology, the authors attemped to identify the physician`s & public attitudes toward brain death. Thirty three statements related to attitude toward brain death were Q-sorted by 71 physicians & 71 laymen. The data were statistically analysed by Q-factor analysis. Five factors in physician group and six factors in layman group could be extracted. Characteristic features of five factors in the physicians were as follows: Factor A: Physicians of this factor positively approve of brain death by pragmatic reason. They agree to organ transplantation, but they resist donation of their own organs in organ transplantation. They are selfish and treasure their body. These people could be named as 「The egoistic brain death advocators」. Factor B: Physicians of this factor approve of brain death for organ transplantation. Most of them are religious. These people could be named as「The humanitarian brain death advocators」. Factor C: Attitude toward brain death in this group is vague. They agree to organ transplantation and also have intention of donation of their own organs and receipt of others. These people could be named as 「The transplantation devotees」. Factor D: These physicians are indifferent in attitude brain death and organ transplantation basically. These people could be named as「The bystanders」. Factor E: These physicians have no trust in phsysicians, religion and modern medicine. They agree to organ transplantation but strongly oppose to brain death. These people could be named as「The doctor mistrustees」. Characteristic features of factors in the laymen were as follows: Factor A: Subjects of this factor positively approve of brain death. They also agree to organ transplantation. They want to receive organs from others but do not intend to donate their own organs because they selfish and treasure their body. These people could be named as「The egoistic brain death advocators」. Factor B: People of this factor approve of brain death and organ transplantation. They are will to donate their own organs. They are mostly post graduated, single females. These people could be named as「The active brain transplantation advocators」. Factor C: People of this factor have somewhat negative attitude toward brain death but approve of organ transplantation. They have no intention of donation of their own organs in viewing traditional concept and attitude. They are mostly religious. These people could be named as 「The traditionals」. Factor D: These persons have no trust in physicians and religion. They have somewhat negative attitude toward brain death. They have no conspicuous opinion toward brain death and organ transplantation. These people could be named as「The doctor mistrustees」. Factor E: This factor was polarized. 「The extreme opposites to brain death」versue「The extreme brain death advocators」were named.「The extreme opposites to brain death」strongly oppsed to brain death and organ transplantation. Attitude of「The extreme opposites to brain death」are mirror image of「The extreme brain death advocators」. Discussion was carried out on the various attitude toward brain death in physicians and laymen.

터너의 색채 표현에 나타난 양극성 연구

孫賢貞 미술사연구회 2004 미술사연구 Vol.- No.18

This paper mainly deals with the characteristics of Joseph Mallord William Turner (1775~1851)'s use of colors, expecially in his later works. It is well known that Turner was deeply interested in optical effects and colors throughout his later period Therefore, most studies on Turner's paintings usually focus on a creative use of light and colors perfectly harmonized on his canvases, and understood Turner's light and colors as a "Romantic Revelation," "Emotional Empathy," or "Forerunner of Impressionism." However, I have found that Turner, particularly, in his later works, consciously experimented with the use of the polarity of colors m order to represent the contrasting subject matters in two companion works. Therefore, this article attempts to discuss anti-Newtonians' thought as one of the influential integrals to Turner's use of colors, and to understand it in relationship with the development of science during that period. In 1704, Isaac Newton published Opticks and discussed that all colors in the spectrum exist in white light Afterwards, many studies began to understand colors in relation to the sunlight. Opposed to Newton's and his followers' hypotheses, Johann Wolfgang van Goethe published a series of articles to argue that colors were not light, but entitles to be experienced in reality In 1810, Goethe published Farbenlehre and discussed that color could be both active and passive to light, and employed this concept as an inspiration for his literary works. Reminded in the image of a magnet, Goethe believed that a natural phenomenon had its own opposing poles like evil and good, and dark and light. This conception of "a pair of opposition" had been already referred in Stoicism, mysticism, magic and alchemy. To Goethe, this conception was both a kind of religion and a logical conclusion. In fact, the anti-Newtoman attitude was not Goethe's own particular Opinion, but rather was a sort of intellectual rebels commonly shared among philosophers during that period against the positivist and mechanistic philosophy that were developing toward a scientific and materialistic point of view throughout the eighteenth and nineteenth century Turner was also fascinated with this anti-Newtoman thought and became deeply indulged with It through the intellectual interactions with his contemporaries such as David Brewster, George Field, J D. Passavant and P J de Loutherbourg Although Turner had been familar with Goethe's theories, his anti-Newtoman attitude became more strengthened after reading Farbenlehre. In addition, the interactions with English scientists like Michael Feraday and Mary Somerville, and photographer J J. E. Mayall, gave him a strong conviction for the polarity of primitive light and dark. Goethe, in his Farbenlehre, perceived yellow and blue as primary colors coming from the two poles of light and dark. Then, according to the color circle, he classified red, yellow and green as plus colors, while blue, blue-green, and purple as minus colors. He characterized plus colors as action, light, brightness, force, warmth, proximity, repulsion, affinity with acids, while minus colors, as negation, shadow, darkness, weakness, coldness, distance, attraction, affinities with alkalis. Turner's works on which the polarities of colors are represented do not only display the contrast of colors, but also intentionally display their contrasting features mentioned in Goethe's Farbenlehre. I believe that it was established as one of Tuner's later stylistic elements. It is found that Turner's interest in light during the 1810s and 1820s developed into an interest in the contrast of light and dark. During 1828~31, his works show that he experimented with a polarity of colors. In 1830s, he contrasted merely yellow and blue, however, after 1840s, he experimented with a broader range of colors and contrasted plus colors such as orange and red with minus colors such as blue, navy and purple. In addition, Turner's works after 1840 share in common to have a octagonal form and circular composition. Such visual elements affirm that Turner intentionally represented the polarity of colors in his later works as I pointed out in this article I believe that this study will provide an opportunity to understand the originality in Tuner's use of colors, and to give a concrete idea about what is "a representation of the polarity of colors."

침수 및 열순환에 따른 레진브라켓 Wing의 파절강도 변화

손지형,황현식 대한치과교정학회 2000 대한치과교정학회지 Vol.30 No.4

본 연구는 침수 및 온도변화에 따른 레진 브라켓 wing의 파절양상을 비교하여 구강내 환경이 레진 브라켓 wing의 물성변화에 미치는 영향을 관찰해 보기 위하여 시행되었다. 본 연구의 재료로 레진 브라켓 75개와 금속 브라켓 25개를 사용하였는데, 레진 브라켓은 상온에서 6개월 동안 방치한 경우와 37℃의 증류수에 6개월 동안 침수시킨 경우, 그리고 37℃의 증류수에 6개월 동안 침수시킨 상태에서 1개월에 350회씩 총 2,100회의 열순환 시킨 경우의 3가지 군으로 구분하여 처리하였다. 만능물성 시험기를 이용하여 금속 브라켓의 경우 wing의 변형강도를, 레진 브라켓의 경우 파절강도를 각 군별로 측정하고 비교 분석하여 다음과 같은 결과를 얻었다. 1.금속 브라켓 wing의 변형강도에 비하여 레진 브라켓 wing의 파절강도가 매우 낮게 나타났으며 통계적으로 유의한 차이가 있었다(p〈0.001). 2.상온에서 6개월 동안 방치한 군에 비하여 침수시키거나 침수 및 열순환 시킨 군에서 브라켓 wing의 파절강도가 낮게 나타났으며 통계적으로 유의한 차이를 보였다(p〈0.001). 3.단순침수에 비하여 침수 및 열순환 시킨 군의 브라켓 wing의 파절강도가 더 낮게 나타났으며 통계적으로 유의한 차이가 있었다(p〈0.001). 이상의 결과는 구강내 환경에 의하여 레진 브라켓 wing의 물성이 약화되므로 이의 강도증가를 위한 적절한 대책이 필요함을 시사하였다. The purpose of this study was to evaluate the effect of oral environment on the strength of resin bracket wings by comparing fracture mode according to water immersion and thermocycling. Seventy-five resin brackets(Spirit MB, Ormco, California) were divided into three groups and treated for six months as follows, (1) untreated, (2) water immersion in distilled water at 37℃, (3) water immersion in distilled water at 37℃ with total 2,100 times of thermocycling taken 350 times each month. Fracture mode of the wing was tested on universal testing machine. In addition to resin brackets, 25 metal brackets were used as controls. Through the statistical analyses, following results were obtained. 1.Resin bracket wings showed significantly lower fracture strength than metal brackets(p〈0.001). 2.Water immersion and water immersion with thermocycling groups showed significantly lower fracture strength than open air condition group(p〈0.001). 3.Water immersion with thermocycling group showed significantly lower fracture strength than water immersion group(p〈0.001). The above results suggest that the mechanical property of resin bracket wing may be influenced by oral environment and further research is needed to improve the strength of the wing in the resin bracket.

열대 지역에서 통일형 초다수성 벼 품종의 생육 및 수량성 비교

이지윤,준현,성환,손영보,송유천,한상익,박동수,권영업,이철원,이종희 忠北大學校 農業科學硏究所 2015 農業科學硏究 Vol.31 No.2

위암세포주에서 Recombinant Human Interferon-r와 Adriamycin의 투여순서가 항암효과에 미치는 영향

홍원선,손영숙,김창민,강윤구,이춘택,김유철,임영혁,남현석,이진오,강태웅 大韓免疫學會 1993 大韓免疫學會誌 Vol.15 No.-

Numerous previous studies, both in vitro and in vivo, have demonstrated that the cytotoxicity can be enhanced by the combination of chemotherapeutic agent and interferons(IFNs) in various types of cancer cells. We have previously reported that combined treatment of MKN-45, human gastric adenocarcinoma cells, with adriamycin(ADM) and recombinant human interferon-r(rh-IFN-r) increased in the cytotoxicity. In this study, the effects of combination timing of rh-IFN-r and ADM on the cytotoxicity against MKN-45 were investigated using MTT assay. MKN-45 was treated with rh-IFN-r and ADM in vitro on three schedules : Treat A ; rh-IFN-r and ADM were treated simultaneously, Treat B ; rh-IFN-r was treated 24 hours after the treatment with ADM, Treat C ; rh-IFN-r was treated for 72 hours and followed by the treatment with ADM. The survival of MKN -45 was inhibited by ADM dose-dependently. 102 and 103U/ml of rh-IFN-r significantly inhibited the survival of MKN-45(% survival : 35.1 ±-1.2% and 34.4 ±1.1% in Treat A and 42.5 ± 2.1% and 45.9-±2.5% in Treat C, respectively). However no difference in the survival was observed between 102 and 103U/ml of rh-IFN-r. Combined treatment with rh-IFN-r and ADM significantly augmented the cytotoxicity at low concentrations of ADM. Combined effects of rh-IFN-r and ADM were evaluated using IC30(,ag/ml) to ADM. IC30s of MKN-45 in Treat A, B and C at 102 U/ml of rh -IFN-r _ were 0.019 -?- 0.003, 0.045 :I:0.001 and 0.054 ± 0.012, respectively, while IC30 of MKN-45 treated with ADM alone was 0.052±0.004. IC30s of MKN-45 in ADM alone group, Treat A, Treat B and Treat C at 103U/ml of rh-IFN-r were 0.047 ±0.003, 0.004 -±0.001, 0.031 ±0.004 and 0.056 0.008, respectively. These results indicate IC30s of Treat A and B were significantly lower than those of ADM alone(p<0.05) and IC30s of Treat A was significantly lower than those of Treat B(p <0.01). IC30s of Treat C, however, were not different from those of ADM alone. From these results demonstrating that cytotoxic effects were increased by the combination of rh-IFN-r and ADM in the order, Treat A > Treat B> Treat C, it can be concluded that the simultaneous administration of rh-IFN-r and ADM may be the most effective method to combine these two therapeutic modalties.

EFFECT OF RESTORATION TYPE ON THE STRESS DISTRIBUTION OF ENDODONTICALLY TREATED MAXILLARY PREMOLARS : THREE-DIMENSIONAL FINITE ELEMENT STUDY

정현숙,김현철,허복,김광훈,손권,박정길 대한치과보존학회 2009 Restorative Dentistry & Endodontics Vol.34 No.1

본 연구의 목적은 다양한 교합하중 조건하에서 아말감, 복합레진, 세라믹 인레이, 그리고 금 인레이로 수복한 근관 치료된 상악 제2소구치의 응력분포를 3차원 유한요소법으로 분석하는 것이다. 발치된 상악 제2소구치를 이용하여 근관 치료된 3차원 유한요소모형을 제작하였다. 제작된 소구치 모형의 근관와동을 위 4가지 재료로 각각 수복한 후, 협측교두 (Load-1) 또는 설측교두 (Load-2)에 500 N의 하중을, 설측교두와 근심변연에 총 170 N의 하중 (Load-3)을 가하였다. 세 가지의 하중조건 하에서 각 수복물에 따른 협측과 설측의 치경부 그리고 교합면의 정중구에서 나타나는 인장응력의 분포양상을 ANSYS 프로그램으로 분석하여 다음과 같은 결과를 얻었다. 1.모든 수복물의 경우에서 Load-1에서는 설측의 치경부, Load-2에서는 협측의 치경부에서 높은 응력이 관찰되었고, 수복물 종류에 따른 차이는 관찰되지 않았다. 2.모든 수복물의 경우에서 교합면의 하중점 근처와 정중구를 따라 높은 응력이 관찰되었고, 수복물 종류에 따라 약간 의 차이가 관찰되었다. 3.모든 수복물의 경우에서 Load-3에서는 하중점 근처에서 높은 응력이 관찰되었고, 수복물 종류에 따른 차이는 관찰되지 않았다. The purpose of this study was to investigate the effects of four restorative materials under various oclusal loading conditions on the stress distribution at the CEJ of buccal. palatal surface and central groove of occlusal surface of endodontically treated maxillary second premolar, using a 3D finte element analysis A 3D finite element model of human maxillary second premolar was endodontically treated. After endodontic treatment, access cavity was filled with Amalgam, resin, ceramic or gold of different mechanical properties A static 500N forces were applied at the buccal (Load-1) and palatal cusp (Load-2) and a static 170N forces were applied at the mesial marginal ridge and palatal cusp simultaneously as centric occlusion (Load-3). Under 3-type Loading condition, the value of tensile stress was analyzed after 4-type restoration at the CEJ of buccal and palatal surface and central groove of occlusal surface Excessive high tensile stresses were observed along the palatal CEJ in Load-1 case and buccal CEJ in Load-2 in all of the restorations. There was no difference in magnitude of stress in relation to the type of restorations. Heavy tensile stress concentrations were observed around the loading point and along the central groove of occlusal surface in all of the restorations. There was slight difference in magnitude of stress between different types of restorations. High tensile stress concentrations around the loading points were observed and there was no difference in magnitude of stress between different types of restorations in Load- 3.

STRESS DISTRIBUTION OF ENDODONTICALLY TREATED MAXILLARY SECOND PREMOLARS RESTORED WITH DIFFERENT METHODS : THREE-DIMENSIONAL FINITE ELEMENT ANALYSIS

임동열,김현철,허복,김광훈,손권,박정길 대한치과보존학회 2009 Restorative Dentistry & Endodontics Vol.34 No.1

본 연구의 목적은 근관치료 된 치아를 구조와 물성이 다른 post와 core 그리고 전장관으로 수복한 후 과도한 교합하중을 가했을 때 치아에 나타나는 응력분포를 조사하기 위함이다. 발치 된 상악 제2소구치를 micro-CT로 단층촬영하고 3D Doctor로 윤곽선을 추출한 다음 HyperMesh Ver. 6으로 삼차원 치아모형을 만들고 다음과 같은 세 가지 방볍으로 수복한 유한요소모형을 제작하였다. 1) 스테인레스 스틸 포스트와 복합레진 코어 그리고 도재소부전장금관으로 수복한 모형 2) fiber 포스트와 복합레전 코어 그리고 전부도재관으로 수복한 모형 . 3)포스트, 코어와 전장관이 일체형인 간접복합레진 EndoCrown으로 수복한 모형. 형성된 모형의 협측 또는 설측교두에 500N의 하중을 가하였으며 하중의 방향은 치아 장축에 대해 45도 이었다. 치관부와 치근부의 von Mises 응력을 ANSYS 9.0 프로그램으로 분석한 결과 포스트와 코어의 형태보다는 전장관 재료의 탄성계수가 근관치료된 상악 소구치의 응력분포를 좌우하였다. 치관부에서는 재료의 탄성계수가 높은 전장관으로 수복한 모형이 낮은 응력분포를 보였다. 치근부에서는 재료의 탄성계수가 낮은 전장관으로 수복한 모형이 낮은 응력분포를 보였다 The purpose of this study was to evaluate the influence of elastic modulus of restorative materials and the number of interfaces of post and core systems on the stress distribution of three differently restored endodontically treatcd maxillary second premolars using 3D FE analysis Model 1, 2 was restored with a stainless steel or glass fiber post and direct composite resin. A PFG or a sintered alumina crown was considered. Model 3 was restored by EndoCrown. An obliquc 500 N was applied on thc buccal (Load A) and palatal (Load B) cusp. The von Mises stresses in the coronal and root structure of each model were analyzed using ANSYS. The elastic modulus of the definitive restorations rather than the type of post and core system was thc primary factor that influenced the stress distribution of endodontically treated maxillary premolars. The stress concentration at thc coronal structure could be lowered through the use of definitive restoration of high elastic modulus The stress concentration at the root structure could be lowered through the use of definitive restoration of low elastic modulus.