Effect of Impact Load on Splice Length of Reinforcing Bars

Hyeon?Jong Hwang,Fan Yang,Li Zang,Jang?Woon Baek,Gao Ma 한국콘크리트학회 2020 International Journal of Concrete Structures and M Vol.14 No.5

Impact loading damage of reinforced concrete (RC) members deteriorates bond strength of reinforcing bars. To understand the effect of strain rate on the bond strength of reinforcing bars in RC beams under impact load, drop hammer test was performed on twenty-four simply supported RC beams with lap spliced bars at the mid-span. The test parameters were reinforcing bar diameter, splice length, drop height, and hammer mass. The dynamic responses including the impact load history, mid-span deflection history, crack distribution, and strain history of reinforcing bar were evaluated. Although the designed bar development length was 31–69% of the requirement of current design codes under static load, the tensile strength of bar splices was greater than the dynamic yield strength when subjected to large impact energy under impact load. On the basis of the test results, existing design equations for the bar development length under static load were modified to consider the impact loading effect on the bond strength. Factors related to the strain rate effect of materials, impact damage, and impact energy loss were proposed. The prediction of the proposed method agreed well with the tensile strength of bar splices under impact load.

김종삼 시에 나타난 타자적 공간 연구

김소현(Kim, So-Hyeon),김종회(Kim, Jong-Hoi) 부산대학교 인문학연구소 2018 코기토 Vol.- No.85

본 연구는 김종삼 시에 나타난 타자적 공간을 규명하는 것을 목적으로 한다. 레비나스의 ‘타자’라는 개념을 차용하여 김종삼 시에 드러난 공간을 단순히 물리적 공간(physical space)만으로 해석하는 것이 아닌, 정신적 공간(mental space), 실존의 구조로서 그의 시 세계를 논하고자 한다. 궁극적으로는 존재(시인)의 타자적인 것들로 구성된 외부적 공간이 결국 존재의 실존 문제와 직결되어있다는 점을 밝혀내는 일이다. 첫째로, 시인이 주체라는 전제하에 어린아이, 여성, 이웃과 같은 타자의 공간을 살펴보았다. 시인이 축조한 세계는 어린아이, 여성, 이웃으로 명명되는 타인의 공간이다. 이러한 타자적 공간 내부에 진입한 시적 주체는 타자들과 마주보는 형태를 보인다. 따라서 시적 주체는 타자의 얼굴을 ‘마주봄’을 통해 자신의 존재를 확인한다. 둘째로, 시인의 비극적 세계인식이 비롯된 근간을 시인이 체험한 전쟁의 상흔으로 보았다. 시인이 끌어온 레바논, 아우슈비츠 수용소 등의 이 국정서의 공간이 결국 전쟁이라는 거대한 메타포 안에서 시인이 체험한 한국전쟁과 동일한 참혹성, 폭압성을 드러내고 있다. 시인은 전쟁을 겪으며 고통 받은 이들의 비애와 비극적 정서를 공유한다. 시인은 본문에서 이국에 대한 단어들을 가감 없이 사용하는데, 여기서 이국이 주는 거리감은 느껴지지 않는다, 시적 주체는 이러한 이국적 벌거벗음 속에서 실재할 수 있다는 점을 밝혀냈다. 셋째로, 시인이 동경한 신성․초월․환상의 공간을 살펴보며 이러한 타자적 공간이 시인을 계속해서 욕망하게 만들고 강한 애착을 갖게 하지만, 사실상 신성 공간으로의 진입은 불가능하며 결국 추방당하게 되면서 주체의 욕망이 좌절될 수밖에 없는 과정을 확인했다. The purpose of this study is to examine the space of otherness found in Kim Jong-sam’s poems. Borrowing the concept of Levinas’ ‘others’, this author intends to discuss the world of his poems by analyzing space revealed in his poems not just as physical space but as mental space and also the structure of existence. Ultimately, it is to reveal the fact that space as the world of externality consisting of others to the being(poet) is directly associated with the existential matters of the being after all. First, this author has understood that the poet examines the space of others, for example, young children, women, or neighbors, under the precondition of an agent and learns that the space of others named as young children, women, or neighbors confronts the agent and allows the agent to exist as the face of others eventually. Second, this researcher regards the origin of the poet having that tragic view of the world is his wound from the war that he experienced, and the space of exotic mood that the poet draws such as Lebanon and Auschwitz Camp reveals the same cruelty and oppression that he experienced from the Korean War within the enormous metaphor of war after all, and he shares the sorrow and tragic sentiment of those in pain suffering from war. This author has learned that distance from the foreign land is irrelevant here and one can exist within that exotic nakedness. Third, examining the space of divinity․transcendence․fantasy that the poet longs for, this researcher has found that that space of otherness lets the poet keep desiring and become strongly attached, but in fact, it is impossible for him to enter the space of divinity, and finally, he gets to be exiled in the end and the agent’s desire ends up withering helplessly.

표피 성장인자의 국소적용이 인체 표피화에 미치는 효과에 대한 연구

김현옥,유성종,정승문,김성수 大韓成形外科學會 1993 Archives of Plastic Surgery Vol.20 No.3

An understanding of the mechanism of healing has increased dramatically during the past decade. The phenomenon of epithelization is important in the normal resurfacing of a donor site or a partial thickness burn wound. This study was conducted to clarify the effect of epidermal growth factor in wound healing of human. Paired donor sites were created in 18 patients who required skin grafting for either burns or reconstructive surgery. One donor site from each patient was treated topically with silver sulfadiazine cream, and the other was treated with silver sulfadiazine cream containing epidermal growth factor(10ug/ml) (Human recombinant epidermal growth factor ; Sigma, St.Louis, Mo). The donor sites were photographed daily, and healing was measured with the use of planimetric anlysis. The donor sites treated with silver sulfadiazine containing epidermal growth factor had an accelerated rate in all 18 patients as compared with that in the paired donor sited treated with silver sulfadiazine alone. Combining data from all patients demonstrated reduced the average time to 100% healing by approximately 2 to 3 days (p<0.01). Light and electron microscopical study of biopsy specimens taken from the centers of donor sites three days after the onset of healing supported these results. In conclusion, epidermal growth factor accelerates the rate of healing of partial thickness skin wound.

溫山工團 海松林의 衰退分析

朴芝賢,金鍾甲 경상대학교 농업생명과학연구원 2002 농업생명과학연구 Vol.36 No.1

울산ㆍ온산공업단지 주변의 해송림을 대상으로 해송의 잎과 토양에 대한 각종 중금속 및 잎속의 수용성 유황함량 등의 오염물질 분석을 통해 주변의 해송림의 활력도를 파악하여 대기오염에 의한 해송임분의 피해 상태를 분석한 결과는 다음과 같다. 산림토양 pH는 경기화학 주변 해송림이 4.01로 가장 낮게 나타났으며 고려화학 주변 해송림을 제외한 모든 조사지역에서 강산성을 나타내었다. 산림토양 내 중금속함량에서, Zn은 6.20~526.42 ppm, Al은 671.69~2,168.41 ppm, Fe은 59.14~171.97 ppm, Cu는 1.87~159.74 ppm, Cd은 0.02~0.68 ppm, Pb은 3.18~48.63 ppm으로 나타났으며, 일반적으로 고려화학 및 경기화학 주변에서 대체적으로 높게 나타났다. 해송 잎속 수용성유황함량은 공단지역이 0.12-0.24 ppm로 나타났으며, 공단외 지역인 진하리에서는 0.08-0.10 ppm로 나타났다. 특히 경기화학 및 여천동지역은 0.16-0.23 ppm로 높게 나타났다. 잎의 연령별함량 분석에서는 3년생>2년생>1년생의 순으로 잎의 연령이 높을수록 증가하였다. 해송 잎속 중금속 함량에서, Zn은 63.57~1,105ppm, Al은 245.9~1,073ppm, Fe은 158.1~1,322ppm, Cu은 34.74~883.5ppm, Cd은 0.09~2.38ppm, Pb은 1.16~67.99ppm으로 나타났다. 잎의 연령별 중금속함량은 3년생>2년생>1년생으로 잎의 연령이 높을수록 중금속함량이 증가되었고, 특히 경기화학 주변의 해송 잎속 중금속함량이 다른 조사지역보다 높게 나타났다. 산림토양과 해송 잎속 오염물질 간이 상관분석에서 토양속의 Cu, Pb과 잎속 Cu, Pb간에는 정의 상관을 나타내어 밀접한 관계가 있음을 알 수 있다. This study carried out to understand the degree of vigour of Pinus thunbergii forest growing around Ulsan and Onsan industrial complex. It was analyzed the pollutants on leaves and soil of P. thunbergii forest. The pH of soil in P. thunbergii forest around Kyunggi chemical co. was the lowest as 4.1 and severe acidity in all survey areas besides Korea Chemical Co. In the content of heavy metals in soil of survey areas, each content of Zn, Al, Fe, Cu, Cd, and Pb showed as 6.20~526.42 ppm, 671.69~2,168.41 ppm, 59.14~171.97 ppm, 1.87~159.74 ppm, 0.02~068 ppm and 3.18~48.63 ppm, respectively, and were relatively high at the forest soil of Kyunggi Chemical Co. and Korea Chemical Co. The content of soluble sulfur in leaves by leaf age showed to 0.12~0.24ppm at each industrial complex besides Jinhari(0.08~0.10 ppm) of non-industrial area, and increased in order of 3-year-old needles, 2-year-old needles and teh current needles. Especially soluble sulfur content in leaves around Kyunggi Chemical Co. and Yochondong complex showed high as 0.16~0.23 ppm. In the content of heavy metals in P. thunbergii leaves at survey areas, the content of Zn, Al, Fe, Cu, Cd, and Pb showed to 63.57~1,105ppm, 245.9~1,073ppm, 158.1~1,322ppm, 34.7~883.5ppm, 0.09~2.38ppm and 1.16~67.99ppm, respectively and increased in order of 3-year-old needles, 2-year-old needles and the current needles. The heavy metal content of P. thunbergii leaves around Kyunggi Chemical Co. was especially higher than other survey areas. In the relationship of heavy metals in forest soils and leaves, there were positive correlations at Pb content and Cu content in soil and P. thunbergii leaves.

초등학교장의 변혁적 지도성과 교사 효능감과의 관계

임종철,김현정 부산교육대학교 교육대학원 2004 논문집 Vol.6 No.-

이 연구에서는 초등학교장의 변혁적 지도성과 교사 효능감과의 관계를 규명하고자 하였다. 문헌연구를 통해 지도성의 개념과 변천과정 학교장의 변혁적 지도성 이론, 교사 효능감에 대한 이론을 살펴 보았으며, 이러한 배경 이론에 근거하여 학교장의 변혁적 지도성의 하위요인으로 결속촉진, 카리스마, 지적인 자극, 개별적 관심을, 교사 효능감의 하위요인으로 자신감, 자기조절 효능감, 과제난이도 선호를 파악하였다. 그리고 선행연구를 통해서 두 변인의 관계를 고찰해 보았다. 문헌연구를 토대로 연구문제를 해결하기 위하여 부산시내 36개 초등학교 교사를 대상으로 학교장의 변혁적 지도성 및 교사 효능감 질문지로 측정하여 상관관계를 살펴본 결과 교사가 인식한 학교장의 변혁적 지도성 수준은 보통 수준 이상(M=3.30)으로 나타났으며, 하위요인별로는 다른 요인에 비해 지적인 자극을 많이 인식하고 있는 것으로 나타났다. 교사의 교사 효능감 수준도 보통 수준 이상(M=3.29)으로 나타났으며 하위요인별로는 다른 요인에 비해 자기조절 효능감을 보다 많이 지각하고 있는 것으로 나타났다. 학교장의 변혁적 지도성과 교사 효능감의 상관관계는 r=.294(p<.001)로 유의한 상관이 있기는 하나 얕은 것으로 나타났으며, 하위요인간의 상관관계에서는 학교장의 변혁적 지도성의 하위요인인 결속촉진, 카리스마, 지적인 자극, 개별적 배려가 교사 효능감의 하위요인인 자기조절 효능감과 유의한 상관이 있기는 하나 얕고, 자신감, 과제난이도 선호와는 상관이 거의 없는 것으로 나타났다. The purpose of this study was to find out the relationship between the elementary school principals' transformational leadership and the teacher efficacy. To achieve this goal, several research problems were established as follows: First, what is the elementary school principals' transformational leadership (contribution to cohesion, charisma, intellectual stimulation and individual concern)? Second, what is the teacher efficacy(confidence, self-control and preference for task difficulty)? Third, what is the relationship between the elementary school principals' transformational leadership and the teacher efficacy? To solve these problems, both the literature research and questionnaire surveys were used in this study. Through the literature research, the concept of leadership and the process of its change was examined, and theory of the school principals' transformational leadership and its background of formation, the concept and the specific character of the transformational leadership, the primary factors and the effects of the transformational leadership were examined. And then it's attempted to find out contribution to cohesion, charisma, intellectual stimulation and concern for individual teachers, which were subordinate factors of principal transformational leadership. Concerning the teacher efficacy, self-efficacy, the concept of the teacher efficacy, the features of teachers with good the teacher efficacy and the elements of the teacher efficacy were examined. As for the teacher efficacy subordinate factors, teacher confidence, self-control efficacy and preference for task difficulty were investigated. Finally, earlier studies were reviewed to identify the relationship of the two factors. Based on the results of literature research and to solve the research problems, 36 elementary schools and 524 teachers of the schools in Busan Metropolitan City were selected randomly. The instruments used in this study were Gweon In-tak's transformational leadership questionnaire and Lee Hyeon-jeong's the teacher efficacy questionnaire. As for reliability, the former's Cronbach α coefficient was .98, and the latter's was .85. The collected data were analyzed with SPSSWIN Ver 10.07 program. The statistical data on mean and standard deviation were obtained, and t-test and F-test were conducted. In case there was any intergroup gap, Scheffe´ test was implemented as post-test, and the correlation between the two factors was measured by calculating Pearson'r. The findings of this study were as follows: First, the teachers considered their principals' transformational leadership to be on the average(M=3.30). By subordinate factors, intellectual stimulation were rated better than the others. Second, as for the impact of their background variables on their perception of principal transformational leadership, the principals were thought to exercise more transformational leadership by those who were lead teachers, had more than career of 20 years, in their 40s and worked at the schools of C and D grade. And they felt that the female principals displayed transformational leadership more than the male principals did. Third, the teacher efficacy is to be on the average (M=3.29). By subordinate factors, they put higher value on self-control efficacy than on the other factors. Fourth, as for the impact of their background variables on their the teacher efficacy, those who were male, lead teachers, had more than career of 20 years, in their 40s, and whose principals were male, viewed the teacher efficacy more favorably. Fifth, there was significant but weak correlation between the transformational leadership of their principals and their self-efficacy (r=.294, p<.001). By subordinate factors, contribution to cohesion, charisma, intellectual stimulation and individual concern had significant yet weak correlation to self-control efficacy, and they were scarcely correlated to confidence and preference for task difficulty. Based on the above-mentioned findings, the following conclusion was reached: First, how principals could be encouraged to exert more transformational leadership should be studied, and a variety of programs should be prepared to boost the transformational leadership of male principals. Second, in which way the teacher efficacy could improve should be considered. Especially, it's necessary to instill more confidence in teachers and urge them to make a challenge to difficult tasks. Third, as principal transformational leadership had weak yet significant correlation to the teacher efficacy, the former factor can predict the latter to some extent. Fourth, since questionnaire method was utilized in this study, future research should make a qualitative approach by using ethnography

백서의 실험적 치아이동시 connexin 43의 발현에 관한 연구

임정현,강경화,이종진,김은철,김상철 대한치과교정학회 2001 대한치과교정학회지 Vol.31 No.5

치아이동시 골세포간 활성 조화에서 세포간 교통의 중요성이 차츰 인식되고 있으며 세포간 교통을 위한 교통반의 존재가 확인되고 있다. 동물실험 모델에서 실험적 치아이동을 통해 조성된 압박 및 견인측 치주인대에서 교통반 단백의 일종인 connexin 43의 발현을 관찰함으로써 인접 연조직 및 골 조직 내에서 세포 신호 전달 양상의 한 부분을 파악하고자 하였다. Sprague-Dawley계 백서 27마리를 대조군(3마리)과 실험군(24마리)으로 나누었으며, 실험군은 견인력(75g)을 가한 후 12시간, 1일, 4일, 7일, 14일, 28일이 경과한 후 각각 4마리씩 희생시켜, connexin 43의 발현을 면역조직화학적으로 관찰한 바 다음과 같은 결과를 얻었다. 1.대조군에서의 connexin 43 발현은 치은, 상아질, 치주인대, 치수, 골세포에서 경미하였다. 2.교정적 치아이동에 반응하는 치수, 치주인대, 골모세포, 파골세포, 골세포부위에서 connexin 43의 발현이 많았으나 치은, 상아질, 상아모세포에서의 발현은 견인력 적용기간에 관계없이 대조군과 큰 차이가 없었다. 3.치수에서 connexin 43의 발현은 교정력을 가한 4일에서부터 증가하여 7일째까지 크게 증가한 후 14일째부터 감소되었으며 28일째에는 대조군과 차이가 없었다. 4.치주인대에서 connexin 43의 발현은 주로 혈관을 중심으로 치조골 면을 따라 압박측에서 주로 나타났는데 교정력을 가한 12시간에서부터 증가하여 4일에서 가장 많은 발현을 보인 후 7일부터 감소하기 시작하였다. 5.골모세포 및 골세포에서 발현은 실험 1일째부터 출현해 4일째에 가장 많은 발현을 보였고 7일 이후에는 크게 감소하였으며 파골세포에서의 발현은 골모세포와 골세포보다 실험 4일째에 더 많이 관찰할 수 있었다. Bone remodeling in response to force requires coordinated actions of osteoblasts, osteoclasts, osteocytes, and periodontal ligament cells. Coordination among these cells may be mediated, in part, by cell-to-cell communication via gap junctions. This study was designed to evaluate the expression of gap junction, connection 43 in periodontal tissue during the experimental movement of rat's incisors, by LSAB(labelled streptavidine biotin) immunohistochemical staining fort connexin 43. Twenty seven Sprague-Dawley rats were divided into a control group(3 rats), and 6 experimental groups(24 rats) where 75g of force was applied from helical springs across the maxillary incisors. Rats of experimental groups were sacrificed at 12 hours, 1, 4, 7, 14 and 28 days after force application, respectively. And the tissues of a control group and experimental groups were studied immunohistochemically. The results were as follows : 1.In control group, the expression of connexin 43 was rare in gingiva, dentin, cementum, periodontal ligament and bone cells. 2.In experimental group, the expression of connexin 43 was increased in pulp, periodontal ligament, osteoblasts, and osteoclasts, comparing to that in control. And it was rare in gingiva, dentin, and odontoblasts regardless of the duration of force application, which was not different from that of control group. 3.The expression of connexin 43 in pulp of experimental group began to increase in 4-day after force application and got to the highest degree at 7-day. And it decreased after 14-day to be similar to that of control group at 28-day. 4.The expression of connexin 43 in periodontal ligament was noted in small capillaries adjacent to alveolar bone, showing higher intensity of immunolabelling after 4-day. And it was stronger in the pressure side than in tension side of periodontal ligament. After 7-day, decrease in connexin 43 expression was observed. 5.The expression of connexin 43 in alveolar bone began to increase 1-day, reached to the highest degree at 4-day, and decreased at 7-day. And the expression in osteoclasts was more than that in osteoblasts or osteocyte at 7-day.

탈회동종골을 이용한 신혈류화골판 형성에 관한 연구

이종호,김현태 大韓顎顔面成形再建外科學會 1995 Maxillofacial Plastic Reconstructive Surgery Vol.17 No.3

Microsurgical vascularized bone transfer has the disadvantages of limitation of available donor sites, loss of donor function, and possibility of donor site defects or deformity. To overcome these shortage of current microsurgical tissue transfer, the method of creating the neovascularized free flap has been introduced. Potentially, this technique must be an innovation in providing the free vascularized bone grafts that are not limited by natural vascular anatomy. But, as could be imagined technique resulted in unavoidable donor bone defect and additional operation for harvesting the autologous bone. The purpose of this study was to evaluate the efficacy of demineralized allogeneic bone as a possible substitute for autologous bone in fabricating the neo-osseous flap. By histologic, microangiographic and radioisotope method, the viability and vascularity of neo-osseous flap, which has been fabricated using allogeneic bone or autologous bone, was assessed in rat model. After 6 weeks, demineralized allogeneic bone showed consistent bone formation and neovascularization. The clinical and microscopic findings of demineralized allogeneic bone group were inferior to those of autogenous bone with regard to bone regeneration. The amount of bone blood floow per dry weight of demineralized allogeneic bone group was significantly higher than that of autogenous bone, even higher that of control intact iliac bone. In conclusion, findings supported that allogeneic bone could be the potential substitute for autologous bone source in creating a prefabricated neo-osseous flap.

유리 신혈류화 골판(遊離新血流化骨瓣)을 有用한 家兎 不顎骨의 再建

김현태,박광,이종호 大韓顎顔面成形再建外科學會 1996 Maxillofacial Plastic Reconstructive Surgery Vol.18 No.2

To overcome the limitations of conventional microsurgical tissue transfer, experimental creation of various neo-flaps using the vessel implantation technique has been reported. We have performed some experiments of fabrication of neo-osseous flap with local vessels and iliac bone slabs to know that the flap vascularity and neo-angiogenesis are achieved enough to microtransfer. As a next step of our previous experiments, the flap viability and the histologic change between the recipient bone and neo-oseous flap was assessed after microsurgical transplantation. The flap was created on the rabbit femoral region(n=25) using femoral vessel and the iliac bone segments(2.5×1.5cm in size). Three weeks after neovascularization, the newly formed flap was harvested and microtransferred to the mandibular defect. As a control, contralateral mandibular defect was created and reconstructed with conventional free iliac bone graft. Scintigrams of experimental group performed 3 days after microtransfer showed hot uptake, while that of control poor uptake. Histologic and vital stain labeling study revealed good bone viability and vascularity of neo-osseous flap. In conclusion, prefabricated neo-osseous flap of our model could be transferred to the recipient site with retaining the flap viability and showed advantages over the conventional bone graft in that it was living bone graft.

외안각 절제술과 경결막 절개에 의한 안와 접근법

정종철,김성범,서지훈,송민석,전창훈,최세훈,김현민 대한악안면성형재건외과학회 2002 Maxillofacial Plastic Reconstructive Surgery Vol.24 No.4

Various surgical approaches to the orbits have been used. But the transconjunctival approach, also called the inferior fornix incision, provides adequate access to the orbital floor with esthetic results. Additionally, transconjunctival approach with lateral canthotomy allows more wide surgical field and good access to the orbital area. Generally, preseptal approach is more used rather than postseptal approach in the transconjunctival incision for the prevention of fat herniation during surgery. There are some complications in transconjunctival approaches but these complications can be prevented with careful surgical techniques. We report clinical results in 12 patients who were treated by preseptal transconjunctival incision with lateral canthotomoy for the treatment of orbital trauma. We were satisfied with this technique for reduction and reconstruction of the orbital trauma and we could also observe relatively good esthetic results.

국내에서 분리된 canine parvovirus의 구조유전자 cloning과 염기서열 분석

박종현,송재영,이중복,현방훈,안수환,전무형 충남대학교 생물공학연구소 1993 생물공학연구지 Vol.3 No.-

In this study gene encoding structural proteins of a CPV isolate was cloned and saquenced to elucidate the molecular genetical properties of the canine parvoviruses isolated from the field. Six recombinant plasmids of pEP3, p1471, p2070, pEP069, pEP338 and p14711p were constructed from the map positions 22 to 98 of RF DNA to clone the VP1 and VP2 genes of CPV-V20. Sequentialy the gene comprising 3780 nucleotides were sequenced by dideoxy chain termination method. When nucleotide sequence of gene encoding the structural proteins of CPV-V20 was compared with those of other strains, CPV-N, CPV-d and CPV-780929 published previously. DNA homologies to CPV-V20 were 99.87% with CPV-NM, 99.73% with CPV-d, 96.85% with CPV-780929 AND 98.4% with FPLV-Carl, respectively. The DNA sequence data of CPV-V20 showed seven point mutations and also deletion of 135 nucleotides from the nucleotide position 4745 to 4879 located in the 3-noncoding region of CPV-N.