• 한국철도학회논문집
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• 제9권1호
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• pp.118-124
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• 2006

SThe rigidities of bridge substructures are the important data in the rail-bridge interaction analysis in Korean High -Speed Railway. This experimental study is being performed because of followings. 1) More correct longitudinal stiffness of the structure including substructure should be considered in the calculation of stresses in rails. 2) There are many uncertainties in the design and construction of the piers and foundations. 3) Actual guideline for the rigidities of piers and foundations in the design is necessary. 4) Measurement on the rigidity of pier according to the types of piers, foundations and soil-conditions is needed. Curve for estimating the total rigidity of substructure will be obtained through this and further experimental studies. It may be used in the analysis of Korean High-Speed Railway bridge and then, longitudinal stresses in the rails can be estimated more accurately. One pair of piers, which consist of pot-bearing for fixed support and pad-bearing for movable support, are loaded by steel frame devices with steel wire ropes and hydraulic jack. The responses which are measured at each loading stages in those field tests are displacements and tilted angles on the top and bottom of piers. This study is being performed testing and analysis about several piers in the construction field.

• 한국임상약학회지
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• 제28권2호
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• pp.88-94
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• 2018

Background: We strived to evaluate the status of nivolumab use and associated factors on the clinical efficacy of the drug. Methods: The study was retrospectively conducted in patients who had been administered nivolumab at least once at the cancer center of Seoul National University Hospital from June 2015 to April 2017. Data were collected from electronic medical records. A medication-use evaluation was performed based on the American Society of Health-System Pharmacists mediation-use guidelines. Results: Sixty-six of the 74 patients (89.2%) showed indications approved for nivolumab use by the Korean Ministry of Food and Drug Safety (MFDS; n=55) or the US Food and Drug Administration (FDA; n=11). Approximately 73.0% of the patients were administered the approved dose of 3 mg/kg but 25.7% were administered an unapproved fixed dose of 100 mg. The overall response rate was 21.7%, and the response rate of non-small cell lung cancer patients, who accounted for the largest number of indications, was 18.8%. Adverse reactions were found in 90.1% of the patients and were mostly mild (86%). The expression of programmed death-ligand 1 (PD-L1) was analyzed as a factor affecting treatment response (p=0.028, odds ratio [OR]=11.331). Conclusion: PD-L1 expression was found to affect treatment response. However, caution is required while using an unapproved dosage and in the absence of monitoring for effectiveness and safety. Therefore, an effective protocol or instruction manual for the proper use of nivolumab should be considered.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.385-388
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• 2008

현대사회는 도시집중화에 따른 인구 과밀화와 시설의 집중이 이루어지고 있다. 이중 건설분야에 뚜렷이 나타나는 현상으로 구조물의 초고층화, 대형화 및 특수화 경향이 두드러진다. 이에 적합한 재료성능향상, 구조 및 설계기술개발 및 시공능력 향상이 요구되고 있다. 고성능 재료와 시공기술을 위해서는 건설재료의 상당 부분을 차지하고 있는 콘크리트의 성능이 우수해야 할 것으로 생각된다. 최근 몇 년 사이에 고성능 콘크리트 중 가장 중요한 부분을 차지하고 있는 초고강도 콘크리트의 연구가 활발하게 이루어지고 있다. 높은 강도를 발현해야 하는 초고강도 콘크리트에서는 미세한 공극에 있어서도 압축강도에 큰 영향을 미치고 있어 이에 대한 세심한 관리가 필요할 것으로 사료된다. 따라서 본 연구에서는 초고강도 콘크리트 영역에서 강도 편차에 대한 범위를 설정 하여 정량적인 강도 관리를 할 수 있도록 하는데 기초적 자료를 제시하고자 한다.

• 한국지반공학회지:지반
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• 제4권1호
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• pp.7-16
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• 1988

현재까지 구조물의 안정을 결정하는 유일한 방법은 안전률개념이 이용되고 있으나, 최근 이 안전 율에 대한 문제점이 제기되어 구조물의 신뢰도에 대한 기준으로 파괴확률을 적용시키고자 하는 연구 가 활발하게 진행되고 있다. 한편 토류구조물은 벽체의 변위형태에 따라 토고분포가 달라짐 에도 불구하고실제문제에선통상 벽 체변위를 고려하지 않는 Coulomb이론이나 Rankine 이론을 이용하고 있는 실정이다. 본 연구에서 는 뒤 채움이 모래로 수평인 연직벽체가 벽체저면을 중심으로 회전하는 주동(AB)과 정 점을 중심으로 회전하는 주동(AT) 2가지 경우를 대상으로 전도에 대한 파양를 다룬다. 동일한 설계조건에 대해서 종래의 Coulomb이론과 Dubrova토력재분포리론. Chang의 방법으로 구한 정적 주동토력과 Seed and Whitmann의 지진하중을 중첩시킨 지진 주동토력을 ,각각 고려하여 최근에 발전된 AFOSM (Advanced First Order Second Moment)해법으로 신협도를 해석하여 비교 검토한다.

• Interaction and multiscale mechanics
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• 제3권1호
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• pp.55-79
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• 2010

The effect of soil-structure interaction on a single-storey, two-bay space frame resting on a pile group embedded in the cohesive soil (clay) with flexible cap is examined in this paper. For this purpose, a more rational approach is resorted to using the finite element analysis with realistic assumptions. Initially, a 3-D FEA is carried out independently for the frame on the premise of fixed column bases in which members of the superstructure are discretized using the 20-node isoparametric continuum elements. Later, a model is worked out separately for the pile foundation, by using the beam elements, plate elements and spring elements to model the pile, pile cap and soil, respectively. The stiffness obtained for the foundation is used in the interaction analysis of the frame to quantify the effect of soil-structure interaction on the response of the superstructure. In the parametric study using the substructure approach (uncoupled analysis), the effects of pile spacing, pile configuration, and pile diameter of the pile group on the response of superstructure are evaluated. The responses of the superstructure considered include the displacement at top of the frame and moments in the columns. The effect of soil-structure interaction is found to be quite significant for the type of foundation considered in the study. Fair agreement is observed between the results obtained herein using the simplified models for the pile foundation and those existing in the literature based on a complete three dimensional analysis of the building frame - pile foundation - soil system.

• Advances in Energy Research
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• 제5권3호
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• pp.227-237
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• 2017

The continuous increase of emission rates of green house gases and the effects on global warming added a new dimension to the problem of substituting the petroleum and its derivatives by environment friendly and sustainable energy sources for the world. Solar and wind energy appear at the top of the list of renewable of high potential, widely available, of dominated technology and well accepted. Brazil is one of the few countries in the world that receives number hours of sunshine exceeding 3,000 hours per year with a daily average of 4.5 to 6 kWh. However, this potential is largely unexplored and poorly tapped. The number of renewable systems implanted in Brazil has grown in recent years, but still insignificant when compared, for example, with Germany and Spain among others. This paper presents the results of an optical study on small concentration solar collector with evacuated tube enveloping the absorber and internal reflective surface fixed on the bottom part of the evacuated tube. The designed collector has a 2D geometrical concentration ratio between 2.455 and 4.91. The orientation of the solar collector, the ratio of the radius of the receiver to the radius of the absorber, the incidence angle for each period of the year, the collector inclination angle, the aperture angle of the reflective surface, concentration and optical efficiency were determined. The ray traces and flux distribution on the absorber of the evacuated tube solar collector were determined by using the program Ray Optics Simulation. The optical efficiency varies during the year according to the solar declination. For the periods were the solar declination is close to zero the efficiencies are maximum, and the variation during the day is around 25.88% and 99.9%. For the periods were the solar declination is maximum the efficiencies are minimum, and the variation during the day is around 23.78% and 91.79%.

• Journal of Plant Biology
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• 제3권2호
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• pp.29-34
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• 1960

From the view point of phytopathological anatomy, the author has tried to study the effect of the shoot cluster disease virus on the internal structure of vascular tissues of chinese date tree (Ziziphus jujuba var. inermis Rehd.) comparing healthy checks and diseased plants. The materials were collected at the several sites, Kumgock-Ri, Masuc-Ri, Kyungi-Do, and near the campus of Korea University and around the area of Chongam-Dong, Seoul City, from August 15th to September 5th 1959. The leaf materials of healthy and diseased plants are fixed and aspirated in two kinds of killing solutions, formalin-acetic acid alcohol solution and Craf III solution. Sections were cut at 5-10$\mu$ thickness and stained with the double staining reagents of safranin and fast green. In this experiment the author has observed that there are marked structural changes in the infected plants in contrast of healthy checks. As figures 3-7 show that the following characteric changes have taken place on infected plants: 1) the arrangement of irregularly developed sieve elements in phloem, 2) the degeneration of phloem elements, 3) the irregular arrangement of epidermis in mid-vein, 4) more necrosis is observed among the parenchymatous cells, 5) abundant accumulatin of starch grains in parenchymatous cells, . In contrast to the above irregularities caused by the virus disease, the healthy checks appear normal structures as shown in figures 1 and 2. In adding to the all features noted above, the author could also observe an interesting feature that the xylem elements in mid-vein vascular bundle tissues are considerably disorganized to show the unspecialized vessel elements, the irregularly arranged xylem elements. However, this kind of irregularities which occur in xylem under the virus infection has not been reported previously. The features noted on the internal structure of vascular bundle under the condition of infection by the shoot cluster disease on chinese date trees appear to be more or less closely similar to the symptoms of the bunchy-top of banana and the yellow dwarf disease of barley in respect to the fact that whether phloem necrosis takes place as a primary symptom or a secondary symptom. In all these disease, primary histological changes of hypoplasia and hypertrophy are preceeded by the necrosis of phloem.

• 대한화학회지
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• 제55권1호
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• pp.92-97
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• 2011

비닐 아세트산염 합성에 대한 1족 알칼리금속 아세트산염의 촉진 효과를 조사하였다. Pd-Au/$SiO_2$ 촉매를 사용한 경우와 사용하지 않은 경우에 대해 에틸렌과 아세트산 간의 기체상 반응에 대해 생성물 선택성과 에틸렌 전환을 비교하였다. 촉진제가 촉매 표면을 안정화시켰으며, 생성물 선택성과 에틸렌 전환을 촉진하였다. 이 촉매 효과는 1족에서 위에서 아래로 내려갈수록 증가하였다. 이것은 아세트산염의 공통이온효과 때문이다.

• 자원리싸이클링
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• 제21권1호
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• pp.49-59
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• 2012

콩고민주공회국(Democratic Republic of Congo, 이하 DR콩고)은 세계적 자원부국으로 특히 코발트, 철광석, 구리, 다이아몬드 등이 풍부하다. 주요 광물자원의 대부분을 수입에 의존하고 있는 한국은 2008년부터 콩고정부와 한국이 항만 건설을 지원하고, 그 보상으로 루붐바시 슬래그재처리를 통해 아연, 코발트, 구리 등 유용광물을 회수해가는 프로젝트에 대한 검토를 추진하여 왔다. 본 연구는 DR콩고의 루붐바시 슬래그 재처리 사업에 대한 경제성 분석을 수행한 것으로, 연구 결과에 따르면 투자회수기간(pay back period)은 6.7년, 순현재가치(NPV) 3,400만달러, 내부수익률(IRR)은 17.4%로 나타났다. 또한 세제, 고정비용, 운영비용, 지원가격 등에 대한 불확실성을 적용한 민감도 분석 결과 프로젝트의 순현재가치는 최저 -2,480만달러에서 최대 9,270만달러로 나타났다.

• 대한두개안면성형외과학회지
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• 제12권1호
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• pp.12-16
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• 2011

Purpose: This study examined the biomechanical stability of four different plating techniques in the experimental model of mandibular subcondyle fracture. Methods: Twenty standardized bovine tibia bone samples ($7{\times}1.5{\times}1.0cm$) were used for this study. Each of the four sets of tibia bone was cut to mimic a perpendicular subcondyle fracture in the center area. The osteotomized tibia bone was fixed using one of four different fixation groups (A,B,C,D). The fixation systems included single 2.0 mm 4 hole mini adaption plate (A), single 2.0 mm 4 hole dynamic compression miniplate (B), double fixation with 2.0 mm 4 hole mini adaption plate (C), double fixation with a 2.0 mm 4 hole mini adaption plate and 2.0 mm 4 hole dynamic compression miniplate (D). A bending force was applied to the experimental model using a pressure machine (858 table top system, $MTS^{(R)}$) until failure occurred. The load for permanent deformation, maximum load of failure were measured in the load displacement curve with the chart recorder. Results: Double fixation with a 2.0 mm 4 hole mini adaption plate and a 2.0 mm 4 hole dynamic compression miniplate (D) applied to the anterior and posterior regions of the subcondyle experimental model showed the highest load to failure. Conclusion: From this study, double fixation with an adaption plate and dynamic compression miniplate fixation technique produced the greatest biomechanical stability. This technique may be considered a useful means of fixation to reduce the postoperative internal maxillary fixation period and achieve early mobility of the jaw.