Determination of Carrier Concentration in Ga1-xMnxAs Using Raman Spectrocopy

명제 성,A Mascarenhas,Cheongy Cheongy,N Samarth,S. H. Chunz 한국물리학회 2003 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.42 No.III

Ga$_{1-x}$Mn$_{x}$As with Curie temperatures ($T_c$) as high as 110 K has recently emerged as an important spintronic semiconductor material. The ferromagnetism in this material arises from the exchange interaction between the free carriers (holes) generated by Mn doping and the Mn$^{2+}$ ions. However, the accurate determination of the carrier concentration in Ga$_{1-x}$Mn$_{x}$As using standard transport techniques is extremely difficult because of the dominant anomalous Hall effect. We have performed spectroscopic measurements of the hole density in four Ga$_{1-x}$Mn$_{x}$As samples ($x = 0, 0.038, 0.061, 0.083$) using Raman scattering intensity analysis of the coupled plasmon-LO-phonon mode and the unscreened LO phonon. The unscreened LO phonon frequency linearly decreases as the Mn concentration increases up to 8.3 \%. The hole density determined from the Raman scattering exhibits a direct correlation to the observed $T_c$, providing an unambiguous means of determining the hole density in this important new class of ferromagnetic semiconductors.

Human Reasoning and Judgmental Errors

Cheongi Kim 경성대학교 산업개발연구소 2004 산업혁신연구 Vol.1 No.-

서로 다른 3차원 장면으로의 3차원 사람 동작 시퀀스 매핑

정천기(Cheongi Jeong),김영민(Youngmin Kim) 대한전자공학회 2022 대한전자공학회 학술대회 Vol.2022 No.6

전복과 광기의 담론: 『원더랜드에서의 앨리스의 모험』 읽기

윤천기 ( Yun Cheongie ) 대한영어영문학회 2011 영어영문학연구 Vol.37 No.1

Many critics have read Alice’s adventures in Wonderland as popular fantasies or fairy tales. This reading could be reached the nonsensical world of Alice’s world. But actually the Alice’s world is not nonsense at all because its underlying meanings are more complicated than fantasies or fairy tales show. Carroll questioned the value of order and principles in the world and explored their sophisticated meanings through ‘the satiric destruction of the common sense.’ By using both ‘episodic dream structures’ and ‘symbolic nonsenses,’ he deconstructed the boundaries of dream and real world, and reversed the order of the world. For Carroll, this was an effective narrative strategy. In fact, it is worth pointing out that the motifs of the reverse and madness in the Alice’s Adventures in Wonderland are almost dramatically composed. Carroll embodies them to create the sensical world beyond the reach of nonsense. ‘What he creates is a cosmic joke but it is more than a good joke’. Carroll shows us moral and philosophical insight into the world, which is based on Victorian society which have a disordered and disoriented world without God. (Seonam University)

대학 입학사정관전형의 편향성: 서울대 입학전형에서의 잠재력, 환경, 다양성 교육의 의미 구성

김천기(Kim Cheongie) 한국교육사회학회 2019 교육사회학연구 Vol.29 No.3

The purpose of this study is to clarify the meanings of student’ potential and environment, and the meaning of diverse and creative education which are key elements that characterize the admission admissions system, in the context of admissions officer system. For this purpose, this study examines the characteristics of the admissions officer system of Seoul National University(SNU) and explores how the meanings of the key elements of admissions officer system are defined and used according to the type and purpose of admissions officer system. The semantics of the key elements in admissions are directly related to the admissions officer s evaluation of the student and can be beneficial or disadvantageous for a certain group of students. As a result of this study, the key elements that characterize the admission admissions system have been specifically defined in the context of the admission screening process. The actual meaning of the key elements used in the context of SNU s admission screening process has been embodied in the following binary relational structures. (a) potential: school records(scholastic achievement) (b) willingness (active, progressive coping ability): environment (c) various and creative school education: uniform school education. In the context of admissions officer system, the specific semantics of potential, environment (or will) and diverse education implies a bias favorable to families with higher income levels and students with ‘special school’ backgrounds rather than the possibility of blocking the influence of the student background and evaluating the pure potential and willingness.

『주홍색 연구』: 낭만적 범죄자의 불법화와 추리소설의 탄생

강관수(Kang, Kwansoo),윤천기(Yun, Cheongie) 신영어영문학회 2020 신영어영문학 Vol.77 No.-

Before a detective novel appeared, the voices of criminals were allowed. In the folktales and literary works, romantic offenders were praised as the heroes who rose against the ruthless rulers. However, they began to be perceived as a threat to a society as capitalism and the private property system were established. With the development of the capitalist society, they became criminals, and simultaneously a detective fiction was born. The important thing in the birth of a detective novel is that the public’s feeling of empathy goes not to transgressing romantic criminals, but to the detectives. This article focuses on the process of romantic criminals becoming illegal in A Study in Scarlet. In this work, a detective’s search for the murderer is seen as an act of practicing justice and a revenge for a lover’s death is a crime who violates the law. In doing so, a legal order is established and a criminal voice is oppressed and illegalized.

유튜브(Youtube) 크리에이터 초등학교 교사들의 정체성과 역할 구성에 대한 생애사 연구

최원준 ( Choi Wonjune ),김천기 ( Kim Cheongie ),이동성 ( Lee Dongsung ) 인하대학교 교육연구소 2021 교육문화연구 Vol.27 No.3

With the advent of the one-person media era, the content creator activities of teachers through media platforms have become a new phenomenon. The purpose of this study is to understand the identity and role of teachers participating in one-person media activities from a social and cultural perspective through life history research of the two elementary school teachers' Youtube creator activities. To this end, the researcher conducted narrative interview with each of the two teachers, and analyzed the collected data through thematic analysis based on practical eclecticism. Firstly, the participants had been reborn as subjects of execution from the messengers of the curriculum. As a related role, the two teachers had developed teaching and life guidance education contents using the art genre, and practiced teaching and learning centering on the student's subjectivity and meaning construction. In addition, the two teachers had reflected on their curriculum literacy. Secondly, the two teachers had become the focal point for the growth and development of the educational subject. As a related role, they had become educational influencers by forming relationships based on time-space expansion, and had formed social and professional capital for the development of the educational community. Through this, the two teachers constantly searching for new roles and meanings rather than settling down in the institutional environment of schools, reflecting on the characteristics of the times, such as strengthening autonomy in expression of opinion, respecting consumers' right to choose, and establishing wide-ranging relationships.

비지도 학습을 이용한 3차원 관절형 대상의 핵심점 추출

배진석(Jinseok Bae),민철희(Cheol-Hui Min),정천기(Cheongi Jeong),김영민(Young Min Kim) 대한전자공학회 2021 대한전자공학회 학술대회 Vol.2021 No.6

With the spread of commercialized depth cameras, it is becoming easier to obtain 3D data in everyday life. Thus, in recent years, massive works have been dedicated to find effective methods to embed 3D data into low-dimensional latent space with the help of state-of-the-art deep learning frameworks. In this paper, we introduce a method to express a sequence of 3D data with a sparse keypoint-based representation. The proposed network robustly extracts keypoints from given observations via discovering an optimal set of points that encodes both shapes and motions in sequence. Also, our method does not require any supervision, and allows frames of raw point cloud data as input. We evaluate our model by qualitive assessment of tracking and conditional generation task on DFAUST dataset.