Light Emission from Graphene

Graphene has attracted great interest due to its superior and unique physical properties. The strong light‐matter interaction with ultrafast and broadband photoresponse of graphene has allowed for the development of state‐of‐the art optical components, such as photodetectors and optical modulators, making this material very promising for ultrafast optical communications. However, so far, light emission from graphene has remained elusive, although this would open the door towards obtaining atomically thin, flexible and transparent light sources and graphene‐based on‐chip interconnects. In this chapter, we review experimental results and techniques of the electrically driven light emission from graphene in the infrared and visible spectrum range

The Effects of Laser Welding Direction on Joint Quality for Non-Uniform Part-to-Part Gaps

Controlling part-to-part gaps is a crucial task in the laser welding of galvanized steel sheets for ensuring the quality of the assembly joint. However, part-to-part gaps are frequently non-uniform. Hence, elevations and depressions from the perspective of the heading direction of the laser beam always exist throughout the gap, creating ascending, descending, and flat travelling paths for laser welding. In this study, assuming non-uniform part-to-part gaps, the effects of welding direction on the quality of the joint of galvanized steel sheets-SGARC440 (lower part) and SGAFC590DP (upper part)-were examined using 2-kW fiber and 6.6-kW disk laser welding systems. The experimental analysis of coupon tests confirmed that there is no statistically significant correlation between the direction of welding and weld pool quality if the gap exceeds the tolerable range. However, when the gap is controlled within the tolerable range, the welding direction can be considered as an important process control variable to enhance the quality of the joint.ope

A Dynamic Information-Based Parking Guidance for Megacities considering Both Public and Private Parking

The constantly increasing number of cars in the megacities is causing severe parking problems. To resolve this problem, many cities adopt parking guidance system as a part of intelligent transportation system (ITS). However, the current parking guidance system stays in its infant stage since the obtainable information is limited. To enhance parking management in the megacity and to provide better parking guidance to drivers, this study introduces an intelligent parking guidance system and proposes a new methodology to operate it. The introduced system considers both public parking and private parking so that it is designed to maximize the use of spatial resources of the city. The proposed methodology is based on the dynamic information related parking in the city and suggests the best parking space to each driver. To do this, two kinds of utility functions which assess parking spaces are developed. Using the proposed methodology, different types of parking management policies are tested through the simulation. According to the experimental test, it is shown that the centrally managed parking guidance can give better results than individually preferred parking guidance. The simulation test proves that both a driver???s benefits and parking management of a city from various points of view can be improved by using the proposed methodology

Plant Location Selection for Food Production by Considering the Regional and Seasonal Supply Vulnerability of Raw Materials

A production capacity analysis considering market demand and raw materials is very important to design a new plant. However, in the food processing industry, the supply uncertainty of raw materials is very high, depending on the production site and the harvest season, and further, it is not straightforward to analyze too complex food production systems by using an analytical optimization model. For these reasons, this study presents a simulation-based decision support model to select the right location for a new food processing plant. We first define three supply vulnerability factors from the standpoint of regional as well as seasonal instability and present an assessment method for supply vulnerability based on fuzzy quantification. The evaluated vulnerability scores are then converted into raw material supply variations for food production simulation to predict the quarterly production volume of a new food processing plant. The proposed selection procedure is illustrated using a case study of semiprocessed kimchi production. The best plant location is proposed where we can reduce and mitigate risks when supplying raw material, thereby producing a target production volume steadily

Clinical disease characteristics according to karyotype in Turner syndrome

Purpose : Turner syndrome (TS) is a disorder in which various anomalies can be accompanied, especially cardiovascular, renal, thyroid and auditory problems. The aim of this study is to identify the incidence of these disorders in patients with TS according to karyotype. Methods : We reviewed medical records of 90 patients with TS diagnosed by chromosomal analysis in 4 hospitals from Jan 1998 to Dec 2007. We evaluated these cases by prepared protocol of 4 medical problems. Results : The distribution of karyotype was 45,X (47.8%), mosaic pattern (34.4%) and structural aberration group (17.8 %). Renal anomalies, cardiovascular anomalies, thyroid disorders and auditory problems are accompanied in 4.4%, 10.0 %, 11.1% and 5.6%, respectively. 45,X group had renal anomalies (7.0%), cardiovascular anomalies (18.6%), thyroid disorders (9.3%) and auditory problems (11.6%). Mosaic group had renal anomalies (3.2%), thyroid disorders (12.9%), no cardiovascular anomalies and auditory problems. Structural aberration group had cardiovascular anomalies (6.3%), thyroid disorders (12.5%) and no other 2 problems. Patients with 45,X group had a significant higher incidence of cardiovascular anomalies (P=0.025). Conclusion : Our results indicate that there are differences clinically according to karyotype of TS, especially in incidence of cardiovascular anomalies

A Radically Assembled Design-Engineering Education Program with a Selection and Combination of Multiple Disciplines

A radically assembled design-engineering program in the school of Design and Human Engineering (DHE) at Ulsan National Institute of Science and Technology (UNIST), newly founded in 2009, is presented. The most distinctive feature in DHE is that all students are required to select two disciplines for their major among three major disciplines, which are; (i) Integrated Industrial Design, (ii) Affective and Human Factors Engineering, and (iii) Engineering and Systems Design. The DHE's major system of the new design-engineering program was developed to foster the next generation designers and engineers, having talent in not only creative ideation but also systematic realization. In this paper, we first describe the founding background, educational rationale and curriculum structure. The curriculum includes students' selective curriculum paths based on their talent and aptitude; collaborative education structure as well as multidisciplinary team-based project courses taught by groups of instructors from different disciplines. Then, the new design-engineering education program is assessed in both quantitative and qualitative ways. The first step of the research is to assess the students' core competencies required in design-engineering combined program by using K-CESA (Korea Colligate Essential Skill Assessment) with 32 students enrolled in DHE. A phenomenological study is also conducted to understand the problems in the current program via in-depth interviews with representative students in DHE. Also, a creative trans-disciplinary short course for students from other universities with various majors (e. g., engineering and design) was offered and tested to evaluate the combined educational system. Finally, we propose the direction for curriculum improvement and follow-up assessment plans, including assessments for students and faculty.open0