• 한국주거학회논문집
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• 제25권5호
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• pp.113-124
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• 2014

The grands ensembles, or large-scale high-rise housing projects, are widely regarded as notorious products of postwar French government policy in the area of housing and urban planning. There was a general consensus that the grands ensembles had been a 'failure'. They were perceived as the source of all the ills of the contemporary city, as responsible for a social breakdown stemming from lack of infrastructure, geographical isolation, and monotonous environments. French government embarked on a broad renovation effort in light of the deteriorated condition of grands ensembles in the 1980s, which has been approved as generally 'successful'. This study focusing on French cases allowed me to demonstrate that following qualifications are critically important for successful housing projects: urban contextual continuity, socially mixed community, authentic planning for achieving sense of place, relationship between collective and individual expression, et cetera.

• 한국임상수의학회지
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• 제21권1호
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• pp.83-86
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• 2004

A 4 year old mixed female dog was presented dyspnea, anorexia and syncope. In blood smear test, a lot of heartworm larvae were observed. In thoracic radiography, "reverse D" shape was observed. So, this case was considered with heartworm disease. In echocardiography, marked left heart hypertrophy was presented. In M-mode view, aortic valvular stenosis was found. After mongrel dog died, aortic valvular stenosis was reconfirmed in necropsy. After all, the dog died of pulmonary edema because of aortic valvular stenosis caused left heart failure.t failure.

• Computers and Concrete
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• 제12권5호
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• pp.585-612
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• 2013

The paper presents quasi-static numerical simulations of the behaviour of short reinforced concrete beams without shear reinforcement under mixed shear-tension failure using the FEM and four various constitutive continuum models for concrete. First, an isotropic elasto-plastic model with a Drucker-Prager criterion defined in compression and with a Rankine criterion defined in tension was used. Next, an anisotropic smeared crack and isotropic damage model were applied. Finally, an elasto-plastic-damage model was used. To ensure mesh-independent FE results, to describe strain localization in concrete and to capture a deterministic size effect, all models were enhanced in a softening regime by a characteristic length of micro-structure by means of a non-local theory. Bond-slip between concrete and reinforcement was considered. The numerical results were directly compared with the corresponding laboratory tests performed by Walraven and Lehwalter (1994). The advantages and disadvantages of enhanced models to model the reinforced concrete behaviour were outlined.

• Journal of Chest Surgery
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• 제27권9호
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• pp.752-758
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• 1994

From July 1983 to December 1992, 145 patients with mitral valvular disease underwent open heart surgery at Chonbuk National University Hospital. Of these patients, 89 patients[61.4%] required mitral valve replacement. 56 patients [38.6 %] had mitral valve repair. There were 32 women and 24 men and the mean age was 34.3 years[range 6 years to 62 years].There were 23 cases of pure mitral stenosis, 19 cases of mitral regurgitation and 14 cases of mixedmitral valvular disease. The mean duration of symptom was 4.53 years and mean mitral valvularorifice diameter[in cases of pure stenosis and mixed mitral valvular lesion] was 0.96 cm. According to the NYHA classification, the distribution of patients preoperatively was as follows; class IIa, 15 patients; class lib, 17 patients; class III, 22 patients; class IV, 2 patients. Four patients[7%] had an embolic history preoperatively. 24 patients[ 43 %] were in atrial fibrillation. In cases of pure mitral stenosis, the technique used included open mitral commissurotomy[21atients], open mitral commissurotomy with mitral annuloplasty[2 patients]. In mixed mitral valvular disease, open mitral commissurotomy[ll patients] and open mitral commissurotomy with mitral annuloplasty[l patient] were performed. In cases of mitral regurgitation, mitral annuloplasty[5 patients], mitral valvuloplasty[6 patients], mitral annuloplasty with valvuloplasty [3 patients] and ring annuloplasty [5 patients] were performed.There was one perioperative death related to acute renal failure and sepsis. One late death was occurred related to heart failure after 10 months postoperatively. One patient required reoperation due to restenosis and no embolic episode was occured. After operation, 34 patients were in NYHA functional class I, 20 patients were in class IIa.

• 한국농공학회지
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• 제44권1호
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• pp.93-102
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• 2002

Steel fiber and polymer are used widely for reinforcement material of RC structures because of its excellences of the durability, serviceability as well as mechanical properties. The purpose of this study is to investigate the shear behavior of polymer cement high strength concrete beams mixed with steel fiber. The compressive strength of concrete was based on the 100$\times$200 mm cylinder specimens. The compressive strength of concrete are 320$kgf/cm^2$, 436 $kgf/cm^2$ and 520 $kgf/cm^2$ in the 28 days. The static test was carried out to measure the ultimate load, the initial load of flexural and diagonal cracking, crack patterns and fracture modes. Also, load-strain and load-deflection examined. During the test cracks were sketched against the load values according to the growth of crack. result are as follows; (1) The failure modes of the specimens are increased in rigidity and durability with mixing steel fiber and polymer. (2) The load of initial crack was similar a theory of shear-crack strength. (3) The deflection and strain at failure load of Polymer-steel fiber high strength concrete beams were increased, improving the brittleness of the high strength concrete.

• 한국지반공학회논문집
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• 제17권4호
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• pp.317-329
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• 2001

서울지하철 터널의 상당 구간이 막장면이 풍화토에서 풍화암까지 변화하는 복합화강토지반에 건설되어 왔다. 화강암풍화지반은 심도에 따라 강도의 변화가 크며, 수위가 높고 투수성 지반인 특징을 갖는다. 터널은 주로 비원형 배수터널로 설계되고 NATM 공법으로 시공되었다. 이와 같은 여건의 터널현장에서 발생하였던 붕괴사례를 조사한 결과, 대부분의 붕괴가 터널 어깨 부근으로부터 시작되었고, 구조적으로 완전하지 않은 라이닝, 그리고 지하수와의 연관성 등의 공통적 특징이 확인되었다. 이러한 터널문제는 지반조건, 시공조건, 터널형상 등 경계조건이 복잡하여 한계평형 해석과 같은 종래의 해석적 방법으로 터널안정을 검토하기가 용이하지 않다. 그 가장 큰 이유중의 하나는 터널의 파괴메카니즘에 대한 분명한 정보를 알 수 없는데 있다. 파괴메카니즘의 조사에는 전통적으로 원심모형시험법이 많이 사용되어 왔다. 그러나 화강토지반내의 터널처럼 복잡한 경계조건을 갖는 터널문제에는 적용하기 어렵다. 따라서 이에 대한 하나의 대안으로서 본 논문에서는 지반거동의 비선형성을 고려하는 Coupled 수치해석법을 이용하여 파괴메카니즘을 조사하였다. 수치해석결과의 증분변위벡터, 누적소성편차변형률 그리고 속도특성치(velocity characteristics)의 분석을 통해 실제 붕괴사례와 잘 일치하는 명확한 파괴메카니즘을 파악할 수 있었다. 이로부터 복잡한 경계조건을 갖는 터널 문제의 안정해석을 위한 파괴메카니즘을 조사하는 수치해석적 접근방법을 제시하였다.

• 대한치과기공학회지
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• 제43권4호
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• pp.160-167
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• 2021

Purpose: In this study, when the etching treatment method, which is a chemical surface treatment method, is applied to colored zirconia, the shear bond strength between the veneering ceramic material and colored zirconia is compared with that without surface treatment, and the fracture type is observed to evaluate the etching treatment effect of colored zirconia. Methods: Experiments were conducted after dividing the study sample into two groups, which are the zirconia control group without surface treatment using colored zirconia blocks (without etching zirconia, NZC group) and the zirconia group treated with a commercially available etching solution (etching liquid zirconia, EZC group). Results: The mean shear bond strength of the NZC group was 20.31±2.32 Mpa, and that of the EZC group was 25.95±2.34 Mpa, and the difference between these two values was statistically significant (p<0.05). Further, the surface roughness Ra value was higher in the EZC group than in the NZC group. In the fracture pattern, cohesive fractures were dominant, and adhesive fractures and cohesive fractures were mixed. Conclusion: The bond strength was significantly higher in the group treated with colored zirconia. The fracture pattern was mostly cohesive failure in the group not treated with etching and changed to mixed failure as the etching treatment progressed.

• 펄프종이기술
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• 제31권4호
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• pp.69-75
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• 1999

This study was performed to investigated the application of mixed resins for corrugated container board. The corrugated container board yields a sandwich structure in which a linerboard material is glued to a corrugated medium . Now, manufacturing corrugated container boards don't provide sufficient strength, and result in box failure during shipping . Therefore improvement of box strength is necessary . In this study, we intend to improve box strength by improving corrugated medium strength with mixed resins and to find the optimum treatment condition of this resins. First, we tried to mixed resins as Starch+CMC, Starch_Irea, CMC+Urea, Second, investigated to applicability of this resins for corrugated medium , and the third, measured tensile index, burst index, and edgewise compression index on liner, medium paper, and single faced corrugated container board. In this test results, we obtained that the improvement ratios of tensile index in liner and medium paper were approximately 80-185%, 60-118% , respectively. The respecting improvement ratios of edgewise compression index of single faced corrugated container board was approximately 91-124%, relatively. In addition, we concluded that optimum condition in mixing ratio was 1 :3 with CMC + Urea and the ap[plication amounts was 9% on materials. Fro manufacture of corrugated container board, optimum condition in mixing ratio was 1 : 3 with 5% CMC +Urea , because of considering to improvement of strength on cost.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 추계 학술논문 발표대회
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• pp.31-32
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• 2018

Lately, cement mixed siliceous powder waterproofing coating has been used as a waterproofing material in the wet environment condition of an underground concrete structure. Underground is exposed to environmental influences such as pressure of ground water, pressure of soil. However, the quality standard for pressure (water pressure, earth pressure) is not specified in the specification of the cement mixed siliceous powder waterproofing coating. Therefore, in this study, the permeability test was carried out based on the assumption that the durability should be verified in consideration of the environmental aspects of the material in actual field. As a result of the test, the permeability was generated from the inorganic single type material, but it was caused by the sealing failure and the test error, and the permeability was not generated in most of the materials. The results of this study will be analyzed by reviewing the physical properties of the material, and the research direction will be resumed.

• 대한전자공학회논문지SD
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• 제38권1호
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• pp.1-12
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• 2001

2차원 소자 시뮬레이터를 이용하는 혼합모드 과도해석을 통해, NMOS 트랜지스터를 ESD 보호용 소자로 사용하는 CMOS 칩에서의 HBM ESD 현상에 대한 과도해석 방법론을 제시하고 HBM 방전 미케니즘에 대해 상세히 분석하였고, 보호용 소자 내에서의 2차항복 현상을 성공적으로 시뮬레이션하여 소자 파괴에 이르는 미케니즘을 설명하였다., 보호용 소자 구조의 변화가 방전 특성에 미치는 영향을 조사하기 위해 DC 해석 결과와 혼합모드 과도해석 결과를 비교 분석하였고, 분석 결과를 근거로 하여 HBM ESD에 보다 견고한 보호용 소자의 구조 설계에 대해 논의하였다.