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.

초등학교 외부공간의 환경친화적 조성계획에 관한 연구

장대희,김현수 대한건축학회 2004 대한건축학회논문집 Vol.20 No.9

The purpose of this study is (1)to supplement City ecological problems and (2) to provide ecological school's outdoors planning factors and methods for setting up the educational space of environmental friendship First, the notion and compositive purpose of ecological schools are established, the ecological formal necessity of outdoor of schools is investigated The ecological problems of elementary schools are also understood by the on-the-spot survey The spacial planning directions and essential examples are viewed by extarcting the ecological outdoor compositive plans With the planning creteria and presentation of the essential element technology

Cholesterol 食餌에 添加한 Pectin 및 Cellulose가 흰쥐의 血淸 脂質에 미치는 影響

張鉉淑 慶北大學校 師範大學 1987 敎育硏究誌 Vol.29 No.-

This experiment was designed to investigate the effect of dietary fibers on serum lipids of cholesterol-fed rats. Twenty-five rats of Sprague-Dowley strain weighed 100±10g were divided into 5 groups, each group receiving a different diet for 3 weeks. And five kinds of animal diets were prepared as follows; 1) Control diet: 65g corn starch contained 18g casein, 10g lard, 5g vegetable oil, vitamin and salt mixture and 1g cholesterol. 2) Ⅰ diet: 4% cellulose was added into the control diet. 3) Ⅱ diet: 8% cellulose was added into the control diet. 4) Ⅲ diet: 4% pectin was added into the control diet. 5) Ⅳ diet: 8% pectin was added into the control diet. The weight of feed was properly adjusted by reducing the content of starch. After sacrificing the animals, the contents of some chemical components in serum were analyzed. The results obtained are summarized as follows; 1) The weight of liver and heart was significantly different between the experimental groups and the control group. 2) The total lipid, total cholesterol, HDL-cholesterol, triglyceride and phosph-olipid contents of serum were not significantly different between the experimental groups and the control group. 3) The ratio of HDL-cholesterol to total cholesterol was significantly increased in pectin 4% group.

Niacin이 조골세포 분화에 미치는 영향

민현영 ․ 장원구 대구대학교 산업기술연구소 2018 産業技術硏究 Vol.29 No.2

Niacin (Vitamin B3) is a necessary nutrient for humans and animals. This study was conducted to examine the effect of niacin on osteoblast differentiation. Previous study shows that precursor of niacin suppress osteoclast formation. However, the mechanism of niacin in osteoblast differentiation is not well known. In this study we investigated the effect of niacin in osteoblasts. Niacin induced osteogenic differentiation marker genes including distal-less homeobox 5(Dlx5), runt-related transcription factor 2(Runx2), alkaline phosphatase(ALP), and osteocalcin(OC). These results suggest that niacin contributes to osteoblast differentiation by inducing the osteogenic genes.

영구자석의 체적 변화가 자력에 미치는 영향

장항익,황현식 대한치과교정학회 1995 대한치과교정학회지 Vol.25 No.2

교정치료시 보다 효과적인 치아 이동을 위한 한 방법으로 최근 자석 사용이 고려되고 있다. 영구자석의 체적 변화가 자력에 미치는 영향을 파악하고자 한 쪽에 한 개의 자석을 고정하고 반대쪽 자석의 두께나 넓이를 일정한 비율로 증가시키면서 양측 간에 나타나는 자력을 비교 연구한 결과 다음과 같은 결과를 얻었다. 1. 두께를 증가시킨 경우에는 자력이 증가하였으나 넓이를 증가시킨 경우 자력이 오히려 감소하였다. 2. 체적 증가에 따른 자력의 증간은 대수함수 분포 양상을 나타내었다. 3. 두께 증가로 체적을 변화시킨 경우, 같은 두께라도 처음부터 크게 제작한 자석이 작은 자석을 여러 개 합한 것보다 큰 자력을 보였다. 본 연구 결과 구강내에서 자력을 증가시키기 위해서는, 마주보는 자석면은 같게 유지하면서 넓이 증가보다는 두께를 증가시키는 방법이, 그리고 처음부터 두꺼운 자석을 사용하는 것이 보다 효율적임을 알 수 있었다. Recently, magnetic forces are considered as a method for more efficient tooth movement. The purpose of this study was to evaluate the effects of the changes of the magnetic volume on the magnetic forces. The universal testing machine and the electronic balance were used for the exact measurement of the force with constant air gap. While the magnet was kept same on one side, the magnetic volume of the other side was increased gradually in four manners. In the first group, the thickness was increased by adding same size of the magnets on after another while the thickness was increased by changing with a thicker magnet gradually in the second group. In the third group, the width was increased by adding same size of the magnets while the width was increased by changing with a wider magnet gradually in the last group. The results were as follows : 1. With the increase of the thickness, the magnetic force increased, while the magnetic force decreased with the increase of the width. 2. The magnetic force according to the change of the magnetic volume showed the distribution of the logarithmic function. 3. An originally thick magnet showed larger force than the added magnets although both of them had same volume.

흰쥐 경동맥 손상 모형에서 체외 방사선조사에 의한 신내막 과증식억제 : Intercellular Adhesion Molecule-1과 Vascular cell Adhesion Molecule-1의 역할 The Possible Role of Intercellular Adhesion Molecule-1 and Vascular Cell Adhesion Molecule-1

강동헌,승기배,장기육,임상현,정해억,임효영,김연실,채장성,김재형,홍순조,최규보 대한순환기학회 1999 Korean Circulation Journal Vol.29 No.9

CAM을 이용한 다지 분기 구조의 설계

조현묵,한일국,기장근 公州大學校工科大學生産技術硏究所 1996 論文集 Vol.5 No.-

In this thesis, Multi-way branch structure is designed to execute multiway branch instruction in the wireless LAN protocol processor. Because this structure substitute CAM(Content Addressable Memory) for target selection unit with label index information of program which branch in multiway according to system variables consist of flags & vectors. The CAM store a set of arbitrary variable conditions. Thus, this structure have feature which assign system value for multiway branch, can programming and reconfigure a set of variable conditions. The Desing of Multiway branch structure used cmn8a library which is 0.8um process of Compass tool, have about 9,500 gates and suitable for basis clock 80MHz of wireless LAN protocol processor.

尹善道의 漢詩와 時調의 考察

윤장현 朝鮮大學校 敎育大學院 國語敎育學會 1983 國語敎育論叢 Vol.4 No.-

翼端 부근의 人工的 面粗度가 揚力에 미치는 影響에 關한 硏究

李璋煥,河在賢 영남대학교 공업기술연구소 1984 연구보고 Vol.12 No.1

In this study we attempted to increase the wing lift by roughen the tip a rear of the wing surface. Two types of the wing shape (one is square and the other is swept) and two types of artificial roughness were used in the wind tunnel experiment. The cross sectional shapes of the wing models were that of NACA 0010 basic thickness form. The lift coefficients of wing models were measured and compared, and proved to gain good results. Maximum lift coefficient of the wing model which has artificial rougness was bigger than that of the smooth surface wing about 32.4%, and the stall angle was also delayed about 6.7˚. The reason of these phenomena was verified by oil-film visualization photographs of wing surface flow shapes. The separation lines of artificial roughness wing models moved back compared with the smooth surface wing, and the sizes of the stall area was also reduced. And it was verified that the adverse flow oriented direction of the arificial roughness is more profitable than random one in the case of line roughness.

광주 신창동유적 : 제1차조사개보

조현종,장제근 한국고고미술연구소 1992 고고학지 Vol.4 No.-

이 글은 국립광주박물관이 광주시의 의뢰를 받아 실시한 광주 신창동 소재 유적에 대한 조사 약보(略報)이다. 유적은 광주-장성을 잇는 국도확포장구간에 포함되었고 공사의 진척에 따라 유적 일부가 잘려나가는 상황에 놓이게 되었다. 특히 유적 일대의 충적 저지대에서는 공사로 인해 패인 지표하 2m 정도의 깊이에 있는 황갈색 사질층과 흑갈색 진흙층에서 볍씨와 탄화미(炭化米) 등이 곡물자료와 함께 일부 가공흔이 나타나는 목재류 등이 채집되었다. 이에 광주박물관은 광주시 등 관계기관과 협의하여 1차로 공사구간에 대한 유구확인을 위한 발굴조사를 실시하게 되었다. 조사는 1992년 6월 26일부터 7월 25일까지 이루어졌다. 그 결과 국내에서는 처음으로 목제 농기구가 출토된 소택지(沼澤地)의 존재가 알려졌으며 이와 함께 초기철기시대에서 원삼국시대에 이르는 것으로 생각되는 토기요지·구상유구(溝狀遺構)·조상유구(條狀遺構)·주거지 등이 확인되었다. 소위 소택지에서는 흑도(黑陶)·고배(高杯)·점토대토기(粘土帶土器) 등 각종 토기류와 함께 칠기고배, 빗(櫛), 검파(劍把), 통발 등 다양한 목제유물과 볍씨 등 탄화미를 비롯한 곡물자료가 발견되었다. 특히 칠기고배를 비롯한 칠기 등과 목제유물은 지금까지 창원 다호리를 비롯한 영남지방에서는 드물게나마 출토된 바 있으나 한반도 서남부지역에서는 초출(初出)의 자료로서 시사되는 바 크다. 또한, 주거지를 제외한 각 유구에서 출토된 토기류의 형태적 특징에서 요지 출토품과 유사성이 인정됨으로써 당시의 생산과 유통에 관한 새로운 인식의 계기를 마련해 주고 있다. 이러한 물질자료들은 유적의 극히 일부에서 출토된 것이지만 아직 밝혀지지 않은 이 시기의 생산양식과 농경문화의 구체적인 실체에 접근하는 데 필요한 하나의 수확이며 고환경의 복원 및 문화발전과 전파문제의 해석에도 많은 도움이 될 것이다. The Shinchang-dong site in Gwangju, Jeollanam-do Province, was excavated by the Gwangju National Museum in 1992, prior to the construction of the national road. The excavation revealed a peat bog, a pottery kiln, a ditch-shaped feature, a dry field-like feature and a dwelling house. Among the materials recovered from the peat bog were 1) lacquer wares and wooden artefacts including a hoe, mounted dishes, a comb, a dagger handle, basketry fish traps, bird's head-shaped scuplture, and various tools for woodworking, 2) potteries including plain-coarse pottery, black-burnished pottery, and pottery with clay stripe along the rim, the shapes of which are mounted dishes, long-necked jars, wide-mouthed bowls, dish-shaped covers and steamers, 3) organic remains including grains and seeds of rice, barley, wheats, cucumber, legumes and apricots, walnut shells, fish bones and snails, 4) accumulations of large quantities of rice husks. Many wooden pieces, planks and tools with some indications of woodworking as well as the existence of posts for hanging wooden implements indicate the use of swamp as the place for woodworking. The pottery kiln was dug in the direction of contour. Its size is 8m in length by 2m in width, and the slopeness of the floor is 5~8°. It is a open kiln without any additional structure such as roof, wall and combustion chamber. The potteries found from the kiln are similar to those from the bog site. The floor plan of dwelling site is a rectangle about 430cm by 320cm, in the depth of 20cm. It has a central hearth in an oval shape, 50cm in diameter. The peat bog, the kiln and other features date to about the late 2nd century B.C. or the 1st century B.C. while the dwelling site dates to the 3rd century AD. Recognizing the importance of the site, it is designated as the NATIONAL HISTORIC SITE NO. 375.