圓弧形狀크랙을 갖는 圓板의 應力擴大 係數에 關한 硏究 : -테프론모울딩法에 依한 實驗的 方法을 中心으로-

權鍾完,金泰圭 慶一大學校 1987 論文集 Vol.3 No.1

The stress distribution in the vicinity of the crack tip in Fracture Mechanics ordinary indicated by stress intensity factors K which have been proposed by Irwin. In the analysis of stress intensity factors, there are many theoretical and experimental method. The stress analysis in photoelastic techniqure is usually done by using difference of the principal isochromatic fringe patterns. In this paper, by the use of Teflon Molding Technique for photoelastic experiment, determination of stress intensity factor of circular disk with an Arc-crack which is subjected to concentrated load have been studied variation of deflected crack angle. As the result, stress intensity factor at crack tip with circular Arc-crack can be obtain the from figure 11 and figure 12.

텔레스코픽 크라운 임플란트 지지 피개의치와 치아 지지 피개의치의 하악골내 응력분포에 관한 유한요소분석

이창규,백장현,김태훈,김민정,김형섭,권긍록,우이형 대한치과보철학회 2012 대한치과보철학회지 Vol.50 No.1

PURPOSE. The purpose of this study was to investigate the stress distribution in mandibular implant-supported overdentures and tooth-supported overdentures with telescopic crowns. MATERIALS AND METHODS. The assumption of this study was that there were 2, 3, 4 natural teeth and implants which are located in the second premolar and canine regions in various distributed conditions. The mandible, teeth (or implants and abutments), and connectors are modeled, and analyzed with the commercial software, ANSYS Version 10.1. Stress distribution was evaluated under 150 N vertical load bilaterally on 3 experimental conditions - between canine areas, canine and 2nd premolars, 10 mm posterior to 2nd premolars. RESULTS. Overall, the case of the implant group showed more stress than the case of the teeth group in stress distribution to bone. In stress distribution to superstructures of tooth and implants, there was no significant difference between TH group and IM group and the highest stress appeared in TH-IV and IM-IV. The stress caused from bar was much higher than those of implant and tooth. TH group showed less stress than IM group in stress distribution to abutment teeth and implant. CONCLUSION. The results shows that it is crucial to make sure that distance between impact loading point and abutment tooth does not get too far apart, and if it does, it is at best to set abutment tooth on premolar tooth region. It will be necessary to conduct more experiments on effects on implants, natural teeth and bone, in order to apply these results to a clinical treatment. 연구 목적: 이 연구의 목적은 텔레스코픽 크라운 하악 임플란트 지지 피개의치와 치아 지지 피개의치에서 지대치의 수와 위치에 따른 응력 분산을 비교하기 위함이다. 연구 재료 및 방법: 본 연구에서는 임플란트를 4개 식립하고 임플란트 지지 피개의치로 설계하였고, 식립 위치를 견치와 소구치 부위에 위치 별로 3개 또는 2개 존재시를 실험군으로 설정하였다. 자연치아를 갖는 경우도 견치와 제2소구치 4개를 가진 경우를 대조군으로 설정하고 부위별로 3개 또는 2개를 가지는 경우를 실험군으로 설정하였다. ANSYS Version 10.1 (Swanson, Inc., USA)로 분석하였다. 결과: 악골내 응력의 경우, 전반적으로 임플란트(IM)로만 구성된 경우가 치아(TH)로만 구성된 경우에 비해 응력이 크게 발생하였다. 상부구조의 경우, 치아군(TH)과 임플란트군(IM) 사이의 차이는 크게 없었으며 편측 견치와 제2소구치에 지대치 또는 임플란트가 위치하는 경우 가장 큰 응력이 나타났고 바(bar)에서 발생된 응력이 임플란트와 치아에서 발생되는 응력에 비해 상대적으로 훨씬 크게 발생하였다. 지대치와 임플란트의 경우, 치아군(TH)이 임플란트군(IM)보다 응력이 작게 발생하였다. 결론: 본 연구의 결과로부터 지대치(임플란트 또는 치아)를 설정할 때는 하중작용점과 지대치 사이의 거리가 너무 길어지지 않도록 지대치의 수와 위치를 확보해야 하며 소구치 자리에 지대치를 확보하는 것이 유리하다. 앞으로, 실제 임상에 적용하였을 경우, 임플란트 및 자연치아와 악골에 미치는 결과에 대한 연구가 더 필요할 것으로 생각된다.

유체로 연성된 직사각평판의 거리 변화에 따른 고유진동 해석

유계형,이명규,권대규,이성철 전북대학교 공학연구원 ( 구 전북대학교 공업기술연구소 ) 2002 工學硏究 Vol.33 No.-

This study dealt with the experimental modal analysis of the perforated rectangular plate coupled with fluid. The natural frequencies of the perforated plate and solid plate in air were obtained by the analytical method based on the relation between the reference kinetic and maximum potential energy and compared with the experimental results. Good agreement between the results was found for the natural frequencies of the perforated plate in air. It was empirically found the natural frequencies of the perforated plate coupled with fluid. The transverse vibration modes, in-phase and out-of-phase, were observed alternately in the fluid-coupled system. Additionally, the effect of distance between perforated plate and solid plate on the fluid-coupled natural frequency was investigated.

부산지역 매출액 상위기업의 위상과 변천사

정성문 · 정지미 · 이규용 · 김건우 · 김권호 · 박수정 · 양태완 · 지준영 · 이우평 신라대학교 부산학연구센터 2020 부산연구 Vol.18 No.2

본 연구는 부산지역의 주요기업 변화를 살펴보기 위해 매출액 기준 전국 상위 1,000대 기업에 속하는 부산기업을 조사하여 비교분석을 실시하였다. 분석결과 2005년에 전국 1,000대 기업 중 46개 기업이 부산에 소재하였는데, 2019년에는 12 개가 줄어든 34개 기업만이 전국 1,000대 기업에 포함되었다. 또한, 전국 상위 1,000대 기업의 매출액 기준으로 부산지역 기업의 매출액 비중은 2005년 1.6%에서 2019년 1.4%로 줄어든 것으 로 나타났다. 이는 수도권 집중현상이 점차 강화되고 있기 때문이다. 한편, 부산지역 매출액 기준 상위 10대 기업은 많은 변화가 있었는데, 2005년 상위 10대 기업 중 2019년에도 상위 10대 기 업에 포함된 기업은 ㈜한진중공업, 르노삼성자동차(주), ㈜부산은행, ㈜서원유통 등 4개뿐인 것 으로 나타났다. 통계적 인과 관계는 확정할 수 없으나 지역 대기업의 쇠퇴 및 유출과 지역의 쇠퇴가 동시에 이루어지고 있어 지역 경제의 침체와 대기업의 쇠퇴 및 유출이 상당한 관계가 있음을 유추해 볼 수 있다. 특히 2011년 이후 지역 주력 제조업 기업들이 1000대 기업 진입에 실패하였다는 점을 주목해 볼 필요가 있다. 지역 제조업 대기업의 이탈 또는 쇠퇴는 지역 생산성 하락에 영향을 미 쳤을 가능성이 높고, 낮아진 지역 산업 생산성이 지역 경제성장률 둔화에도 영향을 미칠 가능성 이 있다. 따라서 지역의 경제활력 저하 문제를 제고하기 위해서는 지역 산업구조 개편 문제와 생 산성 향상 방안에 대한 고민이 필요하다.

벼 大單位 增産團地栽培에 關한 經營實態調査 : 慶南地方의 5個 團地를 中心으로

金厚根,金正敎,尹泰圭,河湖成,張權烈 慶尙大學校 1975 論文集 Vol.14 No.-

Recently large scale cooperative rice production system has been promoted. This cooperative rice production system is intended to promote introducing a set of new technology which may not be suitable for individual small scale farms to adopt. And this system is believed to be one of important public programs to achieve productivity growth policy goal in Korea. Nevertheless, there seem to exist several problems for this public program to widely introduce to over-all nation. This is one of main objectives that this study intends to investigate. In order to study comparative characteristics of the large scale rice cooperative farm in terms of resource base and organization 99 farms which are member farms and 100 farms which are non-member individual farms have been selected and interviewed from five large scale cooperative farm areas in Gyeong-Nam Province in 1974. The important findings can be summarized as follows: 1) Most of operators af both classes belong to age cohert 40∼50, but the average educational level for member farm operators is higher than that for non-member. 2) The average scale Of rice paddy for member farms, 13.1 tanbO, is larger than that for non-member, 10.6, and the same thing is true for average size of rice paddy plots which is, respectively, 805 pyeong and 690. 3) Completely irrigated paddy for member farms is 99 percent of total paddy owned whereas that for non-member is 81, and consolidated paddy for member farms is 67 percent while that for non-member is 26.4. On the other hand, technically improved paddy other than indicated above for member farms is 32 percent, but that for non-member is only 8.3. 4) Number of rice varieties adopted is 9 for both classes. The most popular variety for member farm is Akibare(36%) whereas that for non-member is Sadominori(29.3%) and Akibare (28.4%). 5) Labor used is 13.5 man per tanbo for member farms and 12.4 for non-member. More labor is used for improving soil quality and protection for member farms whereas less labor is used for preparatory works such as seed bed, sterilization, and water management in the case of the member farm. 6) In the case of member farms, the type of work which is achieved cooperatively by more than 70 percent is purchasing or exchaging seeds, sterilization, and plant protection. Despite seed bad, water management, transplanting and the like being more or less suitable for cooperative work, the proportion of those works done cooperatively is relatively small as compared to what we expected. 7) According to farmers interviewed, variety selection, plant protection, seed bed, transplanting fertilization, water management, and harvesting works are more easier for cooperation, in order importance. 8) Cooperative farmers were cultivating a leading variety, Tongil, which showed higher yields than ordinary varieties and had a desire to be released a new high yielding variety which has a characteristics of highly resistance to dsease and insect. 9) Cooperative farmers were forced to begin the nusery bed earlier than the individual farmers and to emphasize on the disease and insect control with more frequencies. 10) Cooperative farmers had benefits in the seedling transplanting earlier and higher planting density than individual farmers. 11) Cooperative farmers had an intention to apply a deep fertilization method arid to dress heavier nitrogen with a reasonable ratio of the basal fertilization to the top dressing. 12) Cooperative farmers had a convenient irrigation system and were available to adopt a summer drainage method. 13) Cooperative farmers controlled the weed with agricultural chemicals arid recognized the control effect of weedcides. 14) In general, it was recognized that there happened somewhat benefit result in disease control in the cooperative farm while a reasonable control effect was not found in heavy prevailing case. The dominant diseases found in the cooperative farm were sheath bright, strip disease and they were to he prevented with a strong efforts. 15) Rice stem borer and grass leaf roller were effelctivey controlled in the cooperative farm, however, plant hoppers was not completely controlled by the usual method because of its unexpected prevalence. 16) The most difficult thing to cooperate they indicate is to supply an adequate amount of labor at appropriate time in tire labor peak season. In this sense, it seems necessary to introduce field machinary in order to achieve the objective of large scale cooperative rice production. 17) Farmers interviewed believe that technology concerning yield increase is most important. in this respect, it is important to develop such new technology, to diseminate its results and to train good quality extension workers. 18) 42 percent of member farm operators indicate that the cooperative system was successful and 25 percent indicate failed. 29 percent of non-member farmers think that the cooperative farm system was successful and 7 percent of them think failed. Thus 55 percent of non-member farmers indicate they are willing to join to the system in the next year, 7 percent of them are not and others have not decided yet. 19) 60 percent of member farmers think that the scale and number of members of the system were too much large to successfully cooperate and 67 percent of them believe that cooperation among members were not very developed, and 42 percent of members suppose what the leader of individual active farms were not very well functioning. 20) Number of member farmers who believe that the yield level in this year is increased as compared that before joining to the system is 3,4 percent, and no one indicated that the yield level is decreased. On the other hand, 22 percent of them believe that by participating to the system the same quality of paddy could produce more rice. 21) About 93 percent of member farmers believe that the system may not lie survived without support of government and i priority must be given to yield technology. 22) About 80 percent of member operators indicate that they would partioipate to the program in the next production year and 23 percent of them indicate that they would participate with the same amount of paddy land as this year. 23) The rice yield level for member and non-member farms is, respectively, 406kg and 346 per tanbo, and the former is 17.3 percent higher than the latter. 24) The cash expenses per tanbo for member and non-member farms is, respectively, 12,311 won and 10,398. 25) The gross revenud per tanbo for both classes is, respectively, 60,024 won, and 51,303 when evaluated by the official price level, and the net income is, respectively, 47,713 won and 40,905. As seen above, the fact that the rice yield level of member farmers, hence, the income level turns out to be higher seems to stem from two basic factors; that is, on the average, the member farmers are operating farm with an improved resource base and they seem to use more the so called conventional inputs with a better yield technology and management. Thus we may conclude that it is important to invest to improve resource quality, to innovate new yield technology and diseminate this innovation. At the same time, in order to more promote the cooperative system, it seems desirable to solve the following problem areas: 1) Number of member farms and paddy area covered by one cooperaitve unit seems better not to he very large. This seems so because there is on much scale economies owing to the nature of technology available to adopt, whereas a large member unit may restrict opportunity of individual members to deeply involve in the process of decision making. Thus we recommend to continue to study finding an optimum size of the unit. 2) As implied already, quality as well as quantity of extension workers and other local officers who lead this program area crucial factor to expand number of unit of the system and hence to achieve the objective of the program. 3) In order to get rid of labor deficit, especially in the labor peak season farm mechanization seems necessary. For this matter, it is worthwhile to promote, first of all, to invent suitable field machinery, secondly, land consolidation and other land improvement projects, and thirdly to innovate a new technology system suitable to mechanized farming. At any rate, it is also necessary for the government to supply an adequate amount of credit and other administrative support.

[PA-0043] Molecular characterization of KIX domain proteins related to organ size regulation in Soybean (Glycine max (L.) Merr.)

Gyu Tae Park(Gyu Tae Park),Sang-Beom Lee(Sang-Beom Lee),Soo-kwon Park(Soo-kwon Park),Yu-na Kim(Yu-na Kim),Dool-Yi Kim(Dool-Yi Kim),Jung-Kyung Moon(Jung-Kyung Moon),Mi-suk Seo(Mi-suk Seo) 한국육종학회 2022 한국육종학회 공동학술발표집 Vol.2022 No.-

Near-infrared absorbance properties of Cu_2−xS/SiO₂ nanoparticles and their PDMS-based composites

Kwon, Young-Tae,Lim, Gyu-Dam,Kim, Seil,Ryu, Seung Han,Hwang, Tae-Yeon,Park, Kee-Ryung,Choa, Yong-Ho The Royal Society of Chemistry 2018 Journal of Materials Chemistry C Vol.6 No.4

<P>We synthesized different Cu2−xS nanoparticles (CuS and Cu1.8S NPs) with localized surface plasmon resonance (LSPR) absorbance in the near infrared (NIR) region and applied a silica layer on the surface of Cu2−xS nanoparticles (NPs) to achieve high photo-stability and dispersion stability. These plasmonic Cu2−xS NPs have been much utilized as thermal shielding materials of energy-saving windows, due to shielding the ultraviolet (UV) and NIR regions, and transmitting the visible (Vis) region. However, this application is limited because Cu2−xS NPs show photocatalyst properties that lead to the decomposition of organic matter, and dispersing these NPs into polymer films is difficult. Herein, silica coating successfully suppressed the generation of hydroxyl radicals on the surface of CuS NPs, which caused the photo-degradation of a polydimethylsiloxane (PDMS) polymer. Furthermore, a silica layer with the structure similar to that of PDMS provided the dispersion stability of CuS NPs. The achievement of good photo-stability and dispersion stability in the Cu2−xS NPs was demonstrated by the thermal shielding effect using a simulated experiment. The temperature change of a box shielded with a CuS/SiO2-PDMS film (Δ<I>T</I> = 6.8 °C) was smaller than that when the box was shielded with common glass (Δ<I>T</I> = 12.7 °C) or a CuS-PDMS film (Δ<I>T</I> = 9.2 °C). This research introduces a new and reliable thermal shielding material.</P>

Highly Porous Polycaprolactone Membrane: A Biocompatible Promotor for Oxidative Hydroxylation of Arylboronic Acids

Gyu-Tae Kwon,In-Kyun Lim,Ueon Sang Shin,김승회 대한화학회 2020 Bulletin of the Korean Chemical Society Vol.41 No.5

Highly porous polycaprolactone membrane: A biocompatible promotor for oxidative hydroxylation of arylboronic acids

Choline Hydroxide as a Versatile Medium for Catalyst-Free O-Functionalization of Phenols

Gyu-Tae Kwon,Seong-Ryu Joo,Soo-Youl Park,김승회 대한화학회 2020 Bulletin of the Korean Chemical Society Vol.41 No.12

A versatile synthetic protocol for benzyl phenyl ether preparation via O-alkylation of phenolic oxygen with readily available benzyl derivatives was demonstrated. The newly designed procedure was carried out using an eco-friendly medium, room-temperature ionic liquid (choline hydroxide), under metal- and base-catalyst-free aerobic conditions. The reaction platform was also successfully applied to phenol protection strategy.

기존 원형교각의 내진성능 향상을 위한 FRP 보강에 대한 이론적 연구

권태규(Tae-Gyu Kwon),최영민(Young-Min Choi),황윤국(Yoon-Kook Hwang),윤순종(Soon-Jong Yoon) 한국콘크리트학회 2004 콘크리트학회논문집 Vol.16 No.1