This study focused on improving the phase stability and mechanical properties of yttria-stabilized zirconia (YSZ), commonly utilized in gas turbine engine thermal barrier coatings, by incorporating Gd2O3, Er2O3, and TiO2. The addition of 3-valent rare earth elements to YSZ can reduce thermal conductivity and enhance phase stability while adding the 4-valent element TiO2 can improve phase stability and mechanical properties. Sintered specimens were prepared with hot-press equipment. Phase analysis was conducted with X-ray diffraction (XRD), and mechanical properties were assessed with Vickers hardness equipment. The research results revealed that, except for Z10YGE10T, most compositions predominantly exhibited the t-phase. Increasing the content of 3-valent rare earth oxides resulted in a decrease in the monoclinic phase and an increase in the tetragonal phase. In addition, the t(400) angle decreased while the t(004) angle increased. The addition of 10 mol% of 3-valent rare-earth oxides discarded the t-phase and led to the complete development of the c-phase. Adding 10 mol% TiO2 increased hardness than YSZ.

The purpose of this study is to investigate the distribution patterns of displacement and acceleration fields in a nonlinear soil ground based on the interaction of high-speed train, wheel, rail, and ground. For this purpose, a high-speed train in motion was modeled as the actual wheel, and the vertical contact of wheel and rail and the lateral contact, caused by meandering motion, were simulated; this simulation was based on the moving mass analysis. The soil ground part was given the nonlinear behavior of the upper ground part by using the modified the Drucker– Prager model, and the changes in displacement and acceleration were compared with the behavior of the elastic and inelastic grounds. Using this analysis, the displacement and acceleration ranges close to the actual ground behavior were addressed. Additionally, the von-Mises stress and equivalent plastic strain at the ground were examined. Further, the equivalent plastic and total volumetric strains at each failure surface were examined. The variation in stresses, such as vertical stress, transverse pressure, and longitudinal restraint pressure of wheel-rail contact, with the time history was investigated using moving mass. In the case of nonlinear ground model, the displacement difference obtained based on the train travel is not large when compared to that of the elastic ground model, while the acceleration is caused to generate a large decrease.

무도상 교량은 레일을 이음매판으로 부설하여 사용하고 있어 과다한 충격이나 궤도 틀림 등의 발생 우려로 인하여 열차의 고속주행이 어려운 실정이다. 열차의 주행안정성을 확보하기 위해서는 상호작용에 영향을 미치는 인자를 분석하여 동적 안전성에 대하여 검토할 필요가 있다. 이 연구에는 열차가 운용중인 판형교량의 현장계측을 통하여 궤도 구조 및 주거더의 충격계수를 도출하고 이를 기존연구와 비교 및 참고하여 열차의 주행속도를 고려한 충격계수의 추정식을 산정하였다. 궤도의 충격계수 산정식은 기존 연구에서 제안한 식과 유사하게 산정되었으며, 무도상교량 거더의 충격계수 산정식과 일본의 철도교 충격계수 식과 비교한 결과, 일본의 철도교 충격계수 식은 본 연구에서 산정한 거더의 충격계수 1배수 식과 2배수 식 사이에 존재하는 것으로 나타났다.

This study investigated the indoor air quality conditions of public transportation according to the changing of seasons and different times of the day. We measured the concentration of PM10 and CO2, which are substances subject to control measures and limits established by Ministry of Environment for public transportation, and compared actual levels whit the legal standard. Public transportation was classified as subway lines (form 1 to 4), trains (KTX, ITX) and buses. The PM10 concentration was measured as being high during peak hours in winter compared to that in summer. On the other hand, the PM10 concentration in trains and buses was shown to be low. The CO2 concentration in public transportation was recorded as being higher than the legal standard. PM10 concentration was affected by the inflow of outdoor air, and CO2 concentration was influenced by the number of people in a particular space or environment. This survey focused on the indoor air quality of public transportation. The basic data could prove useful in formulating policies to promote and maintain good indoor air quality with regard to public transportation.

With the recent remarkable improvements in the average speeds of contemporary trains, a necessity has arisen for the development of new friction modifiers to improve adhesion characteristics at the wheel-rail interface. The friction modifier must be designed to reduce slippage or sliding of the trains’ wheels on the rails under conditions of rapid acceleration or braking without excessive rolling contact wear. In this study, a novel composite material consisting of metal, ceramic, and polymer is proposed as a friction modifier to improve adhesion between wheels and rails. A blend of Al-6Cu-0.5Mg metallic powder, Al2O3 ceramic powder, and Bakelite-based polymer in various weight-fractions is hot-pressed at 150oC to form a bulk composite material. Variation in the adhesion coefficient is evaluated using a high-speed wheel-rail friction tester, with and without application of the composite friction modifier, under both dry and wet conditions. The effect of varying the weighting fractions of metal and ceramic friction powders is detailed in the paper.

천상열차분야지도에는 단일한 시간이 아니라 다른 시간들이 한자리에 놓여있다. 천상열차분야지도라는 하나의 도면에는 다층의 관측시기와 제작(석각)시기가 공존한다. 특정한 천문현상의 관측시기와 그것을 제작 기록한 시기가 꼭 일치하는 것도 아니다. 그러므로 필자는 천상열차분야 지도의 시기에 관한 연구에 있어서 물리적 시차뿐 아니라 제작자(편집자)의 인식의 문제를 고려해서 살펴보았다. 본고에서는 천상열차분야지도의 분석범위를 線으로 한정하였다. 주위를 두른 365개의 눈금선과 12궁을 나눈 線과, 28宿를 구분한 線과, 적도면을 그린 둥근 원과 그것과 교차해서 그린 황도면을 그린 원에 한정하였다. 내용상으로는 12궁도수와 황도적도교점에 한정해 살펴보았다. 그 결과 세 개의 시간 층을 발견하였다. 세 개의 시간 층은 전국시기의 전욱력, 한대의 사분력, 당대의 대연력에 해당한다. 역사의 흐름 속에서 보면 전시대의 시간들을 새겨서 보존하는 일의 여부는 후대 사람의 의식에 달려있다. 천상열차분야지도에는 서로 다른 과거의 시간들을 단절하지 않고 한자리에 놓기 위한 의도를 지니고 있었다. 그래서 과거의 원형과 기록을 다 잘라버리고 새로 시작하는 방식을 사용한 것이 아니라, 현재에는 더 이상 부합하지 않더라도 오래전 사용되었던 원형을 담아주고 싶었던 방식을 택하였다. 그렇기 때문에 천상열차분야지도의 12궁도수에는 전욱력 시절의 천문 원형이 담겨있다. 천상열차분야지도의 황적교차점에는 한 대와 당대의 천문원형이 담겨있다. 비대칭이 되는, 과학의 실측차원에서만 보면 이상한 도형이 산출되었다. 그러나 또 다른 관점으로 해석해보면 문화의 원형을 보존함으로써 미래로 전하고자 하는 원형보존의식이라 할 수 있다.

The key to solving the race conflict problem is that you need to find a train profile of viable trains, that is, a schedule of integrated trains, in a sufficiently short time, while maintaining safe seizure. In the previous research, we proposed a two-step solution through partitioning and deconstruction of the problem and discretization of the path. However, this method has a limitation in that it cannot be applied only at the nodal point. In this study, we tried to obtain a train schedule that considers the safety profile and considers the more secure and microscopic viewpoint by overcoming the limitation of the existing model by continuously considering the speed profile without disassembling the problem. To do this, we propose a method of modeling the detailed schedule decision step as a continuous variable in the existing twostep solution and approximate the calculation based on several functions.

This study investigates changes in the mechanical behaviors, especially hardness and indentation load-displacement curves, of thermal barrier coatings (TBCs) brought about by thermal shock. The TBCs on the Nickel-based bondcoat/superalloy was prepared with diameters of 25.4 mm and 600 μm thickness. The results of thermal shock cycling test from 1100 oC of the highest temperature indicate that the thermal shock do not influence on the mechanical behavior, but a continuous decrease in porosity and increase in hardness were observed after 1200 thermal shock cycles; these changes are believed to be due to sintering of thermal barrier coating materials. The results that no degradation in the indentation load-displacement curves indicate that the coating shows good thermal shock resistance up to 1200 cycles at 1100 oC in air.

Recently, with development of city traffic network planning, there are various effects with living space from vibration of railway. But, study which about effect from vertical vibration in floor slab in nearing structure is lack in nowadays. This thesis have analysed result from acceleration response per distance as well as proceed with serviceability evaluation and extracted natural frequency from measuring vibration of railway using mobile phone application which is oriented for building which have distances about 5m to 22m from railway.

The train-centric control systems development has some distinct points in that a big size of government budget is in general expended in there and the development duration seems to be long. In addition, the changes are ever made continuously in the capability and operational requirements for Trains. Thus, the impact of the potential changes in the required operational capability on the development activities can induce some type of project risks [7]. As such, proper management of project risk has been one of crucial subjects in the train systems development. All these notes combined together make it the significance of the safety management process be raised further up in the train-centric control systems development. As such, the underlying safety management process should be capable of appropriately handling the potential risks that can be created due to the unexpected changes and the long-term development period. The process should also be complemented for the safety consideration of train-centric control systems, for instance, stop. To study these aspect is the objective of the paper. To do so, a step-by-step approach to analyzing the safety management process is first presented. Then, to enhance the process some necessary and useful activities are added in terms of risk and safety management. Then, to pursue some enhancement on the process, a set of necessary and useful activities are added in terms of risk and safety management. The resultant process is further analyzed and tailored using a design structure matrix method. The resultant process is applied in a train-centric control development as a case study.

가속도를 계측하여 부상력을 제어하는 것은 가장 기본적인 자기부상열차의 부상공극 제어기법이다. 이에 이 연구에서는 가속도 되먹임에 기반한 부상공극제어기법을 자기부상열차에 적용하고, 이를 고려한 자기부상열차-가이드웨이 상호작용계의 동적거동 해석기법을 개발한다. 개발된 해석기법을 사용하여 실제 자기부상열차-가이드웨이 상호작용계의 동적해석을 수행하였다. 해석 결과를 통해 가속도 되먹임에 기반한 부상공극제어기법을 적용하여도 현재까지 제안된 자기부상열차 설계 기준을 충분히 만족함을 확인하였다. 즉, 현재 제안된 자기부상열차 가이드웨이 구조물의 설계 기준을 보완하여 안전하면서도 경제적인 구조물의 건설이 가능해질 것으로 예상된다.

Resonance occurrence conditions are explored by performing dynamic interaction analysis of arch bridge and KTX trains. The target bridge is a 3D tied-arch bridge having span length of 120m. KTX trains consist of two power carriages, two power and passenger carriages and sixteen passenger carriages. When KTX trains run on the target bridge with the uniform speed of 100 to 500km/h, the dynamic responses of the bridge induced by moving trains are obtained from railway arch bridge-train interaction analysis. Two resonance conditions are presented and whether the resonance phenomena occur or not at the suspicious resonance velocities is rigorously investigated through bridge deflections and accelerations and their FFT analysis.

This study was carried out to estimate odors emitted from toilets in Mugunghwa trains. Two parameters, odor intensity and odor concentration, were used for odor estimation. A direct olfactory method to observe odor intensity for 67 toilets and an air dilution olfactory method to estimate odor concentration for 6 samples were performed. Results showed that odor concentrations in toilets in trains ranged from 6 OU/m3 to 30 OU/m3, and odor intensity in 67 toilets varied from 0 degree to 3.3 degree. The results suggest that odors emitted from existing toilets should be controlled because the odor intensity in 16 toilets reached a level that resulted in complaints about the odor.

근대의 상징이자 영화의 탄생과도 밀접하게 연결되어 있는 기차라는 공간은 견고하게 짜여진 사회체제의 상징적으로 보여주고 있다. 봉준호 감독의 <설국열차>는 좀 더 구체적으로 ‘기차’라는 좁고 폐쇄된 공간에서 인류의 멸망을 막는다는 목적으로 운행되고 있다. 그리고 기차 칸칸마다 철저하게 구별되어 있는 계급사회를 살아가는 인간의 생존 방법에 대해서 보여 주고 있다. 이 논문에서는 이런 ‘기차’로 상징되는 폐쇄적 사회체제가 <설국열차> 작품을 통해서 어떻게 작동하고 진행되는지를 정치사회적 측면에서 분석하고 있다. 이를 통해 봉준호 감독의 <설국열차>는 인간사회에서 개인의 행위가 어떻게 형성되고 발생하는지 그리고 그런 행위들이 모여 집합행동으로 이 어질 때 어떤 결과와 변화가 생길 수 있는지를 적극적으로 확인시켜 주는 작품임을 알 수 있다.

정밀한 공정을 요구하는 반도체 및 TFT-LCD와 같은 첨단 기술산업 공장의 미진동 문제는 제품의 성능에 영향을 주는 주요한 인자로서 정밀기기 및 부품의 제조공정에 있어서 중요시 되어왔다. 본 논문에서는 이러한 첨단시설물의 미진동 문제를 해결하기 위하여 기초면진시스템의 미진동제어성능을 검토하였다. 이를 위하여, 기차에서 유발되는 인공지반운동을 생성하여 시간이력해석을 수행하였고 3층 예제구조물을 사용하였다. 수치해석을 통하여 수동 기초면진 및 스마트 면진시스템의 미진동제어성능을 고정기초구조물과 비교하였다. 그 결과 스마트 면진시스템이 미진동제어에 있어서 우수한 제어성능을 나타내는 것을 확인하였다.

공항철도 1단계 개통 전 시운전 중 직통열차가 무정차 정거장인 화물청사역을 통과할때 발생된 열차풍으로 인하여 마감재인 천장판이 마치 파도처럼 출렁이다가 떨어지는 현상이 발생되었다. 이 현상을 처리하기 위해 화물청사역에 풍압 및 풍속에 대한 측정시험을 실시하여 직통열차 무정차 통과로 발생된 열차풍이 건축마감재에 미치는 현상을 조사하고 발생된 열차풍에 대한 지하정거장내 이동 경로를 파악하였다. 또한 홍대입구정거장 축소모형을 제작하여 모형열차를 운행 열차주행실험을 실시하였다. 이 결과를 분석 종합 평가하여 공항철도 2단계 지하역사에 반영하여 쾌적한 지하 환경을 조성하고 앞으로 직통열차가 계획되거나 계획 예정인 지하정거장에 적용하여 직통열차 통과로 발생된 열차풍을 최소화하는 방안을 제시하였다.