http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Conceptual Design of a Table-top Terahertz Free-electron Laser
Y. U. Jeong,S. H. Park,K. Lee,J. Mun,K. H. Jang,J. Y. Lee,J. Sunwoo,김경남,Y.-H. Cha,B. H. Cha,D. H. Kim,G. M. Kazakevich 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.51
We have designed a table-top terahertz (THz) free electron laser (FEL). The main issue of the FEL design is to decrease radiation losses at the FEL resonator except outcoupling ratio. Also reducing the number of undulator periods and total undulator length is important to increase FEL conversion efficiency and to reduce its size. The FEL consists of a magnetron-based microtron having an energy of ∼5 MeV, a strong electromagnetic helical undulator having the period of ∼25 mm, and a cylindrical waveguide-mode optical resonator. The total diameter of the microtron is approximately 60 cm and the macropulse current is more than 50 mA. The condition for low-loss and high-gain oscillator of the table-top FEL has been studied by using a 2-D FEL code. Injection scheme of the electron beam to the undulator was optimized by calculating beam trajectories with a 3-D PIC code. The average THz power is calculated to be 1 W with the tunable wavelength range from 200 μm to 500 μm. The size of the system is expected to be 1 × 2 m<SUP>2</SUP>. The FEL is expected to be used for the real-time imaging of security inspection.
장유정 ( Chang¸ Yu-jeong ) 한국초등도덕교육학회 2021 초등도덕교육 Vol.- No.74
기후변화가 환경과 생태계, 인간의 삶에 미치는 영향이 커지면서 기후변화 교육의 중요성이 부각되고 있다. 이에 본 연구는 생활과 윤리 과목에서 내실 있는 기후변화 교육 방안을 마련하기 위해 교과서의 기후변화 관련 교육 내용을 분석하였다. 『생활과 윤리』 교과서는 기후변화의 의미와 특성, 영향, 대응 등 기후변화 교육의 내용요소를 모두 서술하고 있었다. 그리고 다양한 자료를 통해 토론, 의견 정당화를 촉진하며 기후변화의 특성, 대응 방안을 스스로 추론해볼 수 있도록 구성되어 있었다. 특히, 기후정의와 같은 내용요소는 타교과 교육과 차별되는 내용으로 기후변화 교육에서 도덕과 교육의 역할을 분명히 밝혀주고 있었다. 반면, 개인적·지역사회적 차원 등 다양한 차원에서 실천 방안을 모색하고 기후변화의 원인을 객관적으로 바라볼 수 있는 내용은 다소 부족하였다. 이에 본 연구는 텍스트의 서술뿐만 아니라 표, 다이어그램. 사진 등의 다양한 자료를 활용해 압축적으로 정보를 제공할 수 있는 방안을 제안하였다. As the impacts of climate change on the environment, ecosystem and human life grow, the importance of climate change education is being highlighted. Therefore, this study analyzed the contents of climate change-related education in textbooks to lay the foundation for substantial climate change education in ‘life and ethics’ subjects. ‘Life and ethics’ textbooks described every content of climate change education, such as the meaning, characteristics, impacts and responses of climate change. In addition, various datum were presented to infer the characteristics of climate change and countermeasures through activities such as discussion and justification of opinions. In particular, it dealt with the issue of climate justice. It provided an education that distinguished from other curriculum education. However, it was insufficient to find ways to act at the individual and local level and provide objective informations on the causes of climate change. Thus, this study is proposed a method to provide informations compressively using not only the descriptions of the text but also various datum such as tables, diagrams, and photos.
Yujeong Park,Hwa Yeun Nam,Joon-Ho Lee 한국응용곤충학회 2018 한국응용곤충학회 학술대회논문집 Vol.2018 No.04
The Bemisia tabaci (Hemiptera: Aleyrodidae) is a pest that sucks a plant's phloem, excretes nectar and infects tomatoes with TYLCV (Tomato Yellow Leaf Curl Virus), causing severe economic damage. In order to explore the cause for occurrence of areas where the genetic structure of B. tabaci MED (Mediterranean) was reversed in a short period of time, this study was conducted. We collected and analyzed the B. tabaci MED populations from tomato greenhouses in some areas where their genetic structure was reversed between two years 2016 and 2017. As a result, the genetic structure of B. tabaci MED populations was found to be close between populations of the nursery and the greenhouses where tomato seedlings were supplied from that nursery, even if greenhouses were located far away each other. Further study is needed to identify the causes for occurrence of abrupt reverse of genetic structures of B. tabaci MED populations observed in some areas throughout the country.
Dense Matter at RAON: Challenges and Possibilities
Yujeong Lee,Chang-Hwan Lee,T. Gaitanos,Youngman Kim 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.9
Dense nuclear matter is ubiquitous in modern nuclear physics because it is related to many interesting microscopic and macroscopic phenomena such as heavy ion collisions, nuclear structure, and neutron stars. The on-going rare isotope science project in Korea will build up a rare isotope accelerator complex called RAON. One of the main goals of RAON is to investigate rare isotope physics including dense nuclear matter. Using the relativistic Boltzmann-Uehling-Uhlenbeck (RBUU) transport code, we estimate the properties of nuclear matter that can be created from low-energy heavyion collisions at RAON.We give predictions for the maximum baryon density, the isospin asymmetry and the temperature of nuclear matter that would be formed during 197Au+197Au and 132Sn+64Ni reactions. With a large isospin asymmetry, various theoretical studies indicate that the critical densities or temperatures of phase transitions to exotic states decrease. Because a large isospin asymmetry is expected in the dense matter created at RAON, we discuss possibilities of observing exotic states of dense nuclear matter at RAON for large isospin asymmetry.
Ongoing endeavors to detect mobilization of transposable elements
Yujeong Lee,Una Ha,Sungjin Moon 생화학분자생물학회 2022 BMB Reports Vol.55 No.7
Transposable elements (TEs) are DNA sequences capable ofmobilization from one location to another in the genome. Sincethe discovery of ‘Dissociation (Dc) locus’ by Barbara McClintockin maize (1), mounting evidence in the era of genomics indicatesthat a significant fraction of most eukaryotic genomes is composedof TE sequences, involving in various aspects of biologicalprocesses such as development, physiology, diseasesand evolution. Although technical advances in genomics havediscovered numerous functional impacts of TE across species,our understanding of TEs is still ongoing process due to challengesresulted from complexity and abundance of TEs in thegenome. In this mini-review, we briefly summarize biology ofTEs and their impacts on the host genome, emphasizing importanceof understanding TE landscape in the genome. Then,we introduce recent endeavors especially in vivo retrotranspositionassays and long read sequencing technology for identifyingde novo insertions/TE polymorphism, which will broaden ourknowledge of extraordinary relationship between genomic cohabitantsand their host.
A CMOS-Process-Compatible ZnO-Based Charge-Trap Flash Memory
Yujeong Seo,Min Yeong Song,Ho-Myoung An,Tae Geun Kim IEEE 2013 IEEE electron device letters Vol.34 No.2
<P>ZnO-based charge-trap Flash technology using a resistive switching mechanism is demonstrated for next-generation nonvolatile memory. This device consists of metal/ZnO/nitride/oxide/silicon in order to make use of the electrical transport in the ZnO resistive switching layer. Compared to the previous devices with perovskite oxide materials used as a conduction path, the proposed device shows faster switching speeds (10 ns/100 μs), lower operation voltages ( ±7 V) for the program/erase ( P/E) states, and higher endurance (10<SUP>6</SUP> P/E cycles), along with comparable retention properties.</P>