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Until now, many attempts have been made to dope graphene in various ways, but each method turned out to have pros and cons. In this study, to overcome the limitations of doping methods, yttrium hypocarbide (Y2C) is investigated as one prospective material to dope graphene, using density functional theory calculations. In monolayer Y2C, the anionic electrons localized away from Y atomic layers are confirmed to contribute to occupied states near the Fermi level. Next, we investigate the electronic structure of graphene in heterojunction with Y2C. Anionic electrons of Y2C occupy the empty states of graphene in graphene/Y2C heterostructure, which makes the Dirac cone of graphene located at about 1.7 eV below the Fermi level. Such charge transfer of anionic electrons to graphene and the flatness of electric cloud of anionic electrons leads to evenly n-doped graphene in graphene/Y2C heterostructure. This suggests that Y2C is a good candidate to dope graphene.

이 논문은 주저자의 석사학위 논문을 기반으로 수정·보완하여 작성하였으며, 2016년도 정부(미래창조과학부)의 재원으로 한국연구재단의 지원을 받아 수행된 연구임(NRF-2016R1A2B4010260).

Recently, spintronics devices using MoS2 and ferromagnetic electrode have been in the spotlight. However, strong Fermi level pinning (FLP) is known to occur between MoS2 and ferromagnetic electrode, resulting in a large Schottky barrier height (SBH), which makes it difficult to inject electron from ferromagnetic electrode to semiconductor. To resolve this problem, we study the reduction of FLP occurring between two materials by investigating the effect of atomic passivation at Ni-MoS2 interfaces on contact behaviors. Such atomic passivation can reduce the FLP and magnetic moments induced at S atoms of MoS2. Especially, the largest decrease in the FLP occurs in the case of H atom passivation. Besides, the N, O, and F atom passivation confirms the possibility of ohmic contact, indicated from small SBHs (~0.2 eV). As a result, the SBH and thus the efficiency of the device can be controlled by atomic passivation at metal-semiconductor interfaces.

This study reviews greenbelt and New Town policy in Korea’s Seoul Metropolitan Area as a case study by developing the step-wise critical juncture and path dependence repetition model originating in the historical institutionalism. The country is considered to be in a developmental state with significant power, and the capital region has been regarded as politically crucial, so the theory is more appropriately applied to the two policies’ changes rather than a gradual institutional developmental model. The results found that decisions on the two policies at the presidential level at critical junctures during times of political change were sustained and reinforced until the next juncture, following the path-dependent tendency across regimes and their political orientation. Because the New Town policy has dominated greenbelt policy since the most recent (third) critical juncture in 1997, the latter is vulnerable despite important environmental issues and a reversal is not expected to occur in the near future.

This study confirmed the general belief of urban planners that mixed land use promotes walking in Seoul, a metropolis in East Asia, by analyzing the effect of mixed land use on the travel mode choice of housewives and unemployed people who make non-commuting trips on weekdays. Using binomial logistic regression of commuting data, it was found that the more mixed a neighborhood environment&rsquo, s uses are, the more the pedestrians prefer to walk rather than drive. The nonlinear relationship between the land use mix index and the choice to walk was also confirmed. Although mixed land use in neighborhoods increased the probability of residents choosing walking over using cars, when the degree of complexity increased above a certain level, the opposite effect was observed. As the density of commercial areas increased, the probability of selecting walking increased. In addition to locational characteristics, income and housing type were also major factors affecting the choice to walk, i.e., when the residents&rsquo, neighborhood environment was controlled for higher income and living in an apartment rather than multi-family or single-family housing, they were more likely to choose driving over walking.

In 1986, Laos opened its doors to the global market. With new economic policy mechanisms in place, the country has developed dramatically over the years. The rapid growth brought forth opportunities as well as challenges. This study analyzes traffic congestion in Vientiane, the capital, with a focus on transport mode choices and inequity among commuters. Due to the lack of a reliable database in Laos, the initial step entailed collecting a set of origin–destination data. A total of 498 samples were randomly processed in the data survey, consisting of personal data, household conditions, and travel behaviors. To identify the flow of transport and mode choices, descriptive analysis and a multilevel logit model were employed. The findings reveal the insufficiency of public transit in Vientiane. The preferred modes of transport are motorbikes and private cars. Commuters who use private cars lie in the higher income group, while the low-income group consists of residents who use motorbikes. In addition, the low-income group takes longer to commute as compared to the high-income group. Overall, the lack of public mode choices encourages the use of private cars, leading to critical inequality between low and high-income groups.

This study clarifies the previously unknown limitations of the entropy-based land-use mix index and suggests conditions under which the index is valid. The land-use mix index has an n-shaped relati...

Using density functional theory calculations, atomic and electronic structure of defects in monolayer GeS were investigated by focusing on the effects of vacancies and substitutional atoms. We chose group IV or chalcogen elements as substitutional ones, which substitute for Ge or S in GeS. It was found that the bandgap of GeS with substitutional atoms is close to that of pristine GeS, while the bandgap of GeS with Ge or S vacancies was smaller than that of pristine GeS. In terms of formation energy, monolayer GeS with Ge vacancies is more stable than that with S vacancies, and notably GeS with Ge substituted with Sn is most favorable within the range of chemical potential considered. Defects affect the piezoelectric properties depending on vacancies or substitutional atoms. Especially, GeS with substitutional atoms has almost the same piezoelectric stress coefficients eij as pristine GeS while having lower piezoelectric strain coefficients dij&nbsp, but still much higher than other 2D materials. It is therefore concluded that Sn can effectively heal Ge vacancy in GeS, keeping high piezoelectric strain coefficients.

In 1995, commercial zones were designated by the Urban Master Plan of Seoul. Most of these areas were located in existing urban areas or station areas, and managed by district unit plans. However the demand for additional designations (or rezoning) of commercial areas has persisted, calling for an e...

This study explores the 1980s Rosario proposal for Seoul and its implementation as part of the urban planning of the city, based on the concept of transit-oriented development (TOD), as an instrument to meet the challenges of housing shortage and road-traffic congestion. The proposal originated as a metropolitan-scale plan to decentralize the old mono-centric spatial structure of the rapidly urbanized city with subway networks, and further included a prototype featuring TOD in an individual subway station area. The integrated approach was an attempt to develop diverse value-capture strategies for self-sustaining transit systems. The Seoul city government included this concept in its first official comprehensive plan in 1990, and has since contributed to Seoul’s development towards becoming a transit-oriented city. This study provides valuable evidence for cities in the developing world that have aspirations to become transit-oriented.

Background With the rapid increase in utilization of imaging endpoints in multicenter clinical trials, the amount of data and workflow complexity have also increased. A Clinical Trial Imaging Management System (CTIMS) is required to comprehensively support imaging processes in clinical trials. The US Food and Drug Administration (FDA) issued a guidance protocol in 2018 for appropriate use of medical imaging in accordance with many regulations including the Good Clinical Practice (GCP) guidelines. Existing research on CTIMS, however, has mainly focused on functions and structures of systems rather than regulation and compliance. Objective We aimed to develop a comprehensive CTIMS to meet the current regulatory guidelines and various required functions. We also aimed to perform computerized system validation focusing on the regulatory compliance of our CTIMS. Methods Key regulatory requirements of CTIMS were extracted thorough review of many related regulations and guidelines including International Conference on Harmonization-GCP E6, FDA 21 Code of Federal Regulations parts 11 and 820, Good Automated Manufacturing Practice, and Clinical Data Interchange Standards Consortium. The system architecture was designed in accordance with these regulations by a multidisciplinary team including radiologists, engineers, clinical trial specialists, and regulatory medicine professionals. Computerized system validation of the developed CTIMS was performed internally and externally. Results Our CTIMS (AiCRO) was developed based on a two-layer design composed of the server system and the client system, which is efficient at meeting the regulatory and functional requirements. The server system manages system security, data archive, backup, and audit trail. The client system provides various functions including deidentification, image transfer, image viewer, image quality control, and electronic record. Computerized system validation was performed internally using a V-model and externally by a global quality assurance company to demonstrate that AiCRO meets all regulatory and functional requirements. Conclusions We developed a Good Practice–compliant CTIMS—AiCRO system—to manage large amounts of image data and complexity of imaging management processes in clinical trials. Our CTIMS adopts and adheres to all regulatory and functional requirements and has been thoroughly validated.

BACKGROUND With the rapid increase in utilization of imaging endpoints in multicenter clinical trials, the amount of data and workflow complexity have also increased. A Clinical Trial Imaging Management System (CTIMS) is required to comprehensively support imaging processes in clinical trials. The US Food and Drug Administration (FDA) issued a guidance protocol in 2018 for appropriate use of medical imaging in accordance with many regulations including the Good Clinical Practice (GCP) guidelines. Existing research on CTIMS, however, has mainly focused on functions and structures of systems rather than regulation and compliance. OBJECTIVE We aimed to develop a comprehensive CTIMS to meet the current regulatory guidelines and various required functions. We also aimed to perform computerized system validation focusing on the regulatory compliance of our CTIMS. METHODS Key regulatory requirements of CTIMS were extracted thorough review of many related regulations and guidelines including International Conference on Harmonization-GCP E6, FDA 21 Code of Federal Regulations parts 11 and 820, Good Automated Manufacturing Practice, and Clinical Data Interchange Standards Consortium. The system architecture was designed in accordance with these regulations by a multidisciplinary team including radiologists, engineers, clinical trial specialists, and regulatory medicine professionals. Computerized system validation of the developed CTIMS was performed internally and externally. RESULTS Our CTIMS (AiCRO) was developed based on a two-layer design composed of the server system and the client system, which is efficient at meeting the regulatory and functional requirements. The server system manages system security, data archive, backup, and audit trail. The client system provides various functions including deidentification, image transfer, image viewer, image quality control, and electronic record. Computerized system validation was performed internally using a V-model and externally by a global quality assurance company to demonstrate that AiCRO meets all regulatory and functional requirements. CONCLUSIONS We developed a Good Practice–compliant CTIMS—AiCRO system—to manage large amounts of image data and complexity of imaging management processes in clinical trials. Our CTIMS adopts and adheres to all regulatory and functional requirements and has been thoroughly validated.

A new town's self-containment under greenbelt regulations is a planner's hope modelled after Howard's historical proposal. A planner chooses whether to increase the new town's size to improve its self-containment or to form satellite-city networks. If the hope is an unattainable goal, a planner in reality should consider mass-transit connection with existing urban centres. The first-generation new towns in Korea can provide an important lesson as they can be categorised into large-sized self-containment towns and mid-sized networked towns, both of which followed transit-oriented developments. By reviewing the historical background and using multilevel multinomial logistic analysis of commuting data, this study confirmed the following results. First, the commuting rate to Seoul from the larger two new towns is no better than from the other three mid-sized towns. Second, networked new towns with the surrounding satellite cities promoted commutes to the periphery, but the rate of automobile usage is high. Finally, as the government invested in improvements of the transit connections, all five new towns achieved the goal of being sustainable regarding transit use. In the automobile age, a planner building a new town under urban containment regulations should embrace the difficulties of achieving a metropolis that is both self-contained and transit-oriented.

Many studies in the public health and urban planning fields have suggested that zoning can promote an increase in physical activity by encouraging walking. New urbanists and smart growth advocates claim that Euclidian zoning results in spatial segregation of land use that actually works against walking activity. Few studies have identified empirically the effects of zoning on walking activity. Employing multiple regression modeling, this study identified the impacts of street-level physical environment and zoning regulations on street-level walking activity in Seoul, Korea. Our results demonstrate that areas zoned for mixed land use have greater potential for pedestrian activity than do other zoning types. In addition, we found that there are signs of interaction effects between street-level physical environment and zoning. This result demands further research to prove that efforts to improve walking-friendly, street-level physical environments should be combined with zoning regulations to promote walking.

This research focuses on the conflicts between urban growth management (UGM) in urban planning policy and the growing influence of globalization and foreign direct investments (FDI) in Vientiane, the capital of Laos. In order to answer the question, “Does FDI affect UGM in the capital city of Laos, Vientiane?” the article explores significant decrees, mandates, technical reports, field surveys, and interviews. The results revealed that FDI has been an important instrument in Vientiane for boosting the economy and supporting urban growth. On the other hand, core conflicts emerged between government growth-management policies and the spatial impact of FDI regarding transformations of land use, the physical environment, sociocultural values, and collaboration stages. Moreover, globalization and FDI not only influence economic growth, but also affect the implementation of UGM in Vientiane. Although the urban planning sector has been rather strict, the investment sector prefers to encourage both FDI and domestic investments by giving incentives. Therefore, to achieve more balanced development for this “least developed country,” collaboration between similar relevant institutions (e.g., planning, investment, and land management) should be considered necessary long-term strategies.

본 연구는 선행연구에서 주요요인으로 도출되었던 가로의 물리적 환경, 접근성, 밀도, 다양성 등의 보행증진요인을 기반으로 가로차원의 변수가 가로활성화에 영향을 미치는지 분석해 보았다. 또한 Jacobs(1961)가 중요하다고 언급했던 업종의 다양성과 Ray Oldenburg(1989), Richard MacCormac(1983)이 주장했던 특정 공간이 가로활성화에 미치는 영향을 살펴보고자 하였다. 본 논문에서는 가로활성화 영향요인 모형을 업종별 유형으로 구분하여 분석해 본 결과, Jacobs(1961)가 주장했던 기본적인 가로 환경, 접근성, 밀도, 다양성 등의 보행증진요인은 주중과 주말의 모형에서 거의 유사한 것으로 나타났지만, Ray Oldenburg(1989), Richard MacCormac(1983)이 주장했던 주요 업종은 주중과 주말에 따라 가로활성화에 영향을 주는 정도가 차이가 있음을 도출했다.