Rhee, Syngman`s independence lines and government-establishing movement

학위논문(박사)--서울대학교 대학원 :국사학과,2001.Docto

A 350-year history of a Chungin family line interwoven with genealogical records and oral history

[No abstract available

Political migration of Korean activists through Czechoslovakia in the post-world war II period

The existence of intra-Korean migration between World War II and the Korean War is well known: North Korean landowners and Christians, South Korean communists, and millions of war refugees fled across the 38th parallel, resulting in over two million separated families on the Korean Peninsula. But there were several Koreans who had resided in the US for decades who found their way to Pyongyang via Prague between World War II and the height of the Cold War. Why did they leave for North Korea? Why through Czechoslovakia? What were their fates after they landed in North Korea? This is a story of eleven Korean activists, from three groups, who left their footprints in Czechoslovakia on their journey between the US and North Korea. Eight of them continued to Pyongyang, two returned to the US, and one remained in Czechoslovakia for good. Eight vanished after arriving in Pyongyang, two survived and led comfortable lives in the US, and one took his own life in desperation in Czechoslovakia. We explore the settings in which their stories unraveled, the destinies of the eleven migrants, and the links among them, corroborated by witness interviews and newly discovered materials from Korean, US, Czech, and Russian archives. © 2017 Kyujanggak Institute for Korean Studies

고분자 발광다이오드를 위한 도핑제로서 DCM 유도체에 관한 연구

학위논문(석사) - 한국과학기술원 : 화학과, 2000.2, [ iii, 51 p. ]A series of derivatives of 4-(Dicyanomethylene)-2-methyl-6-[p-(dimethylamino) styryl]-4H-pyran (DCM) have been synthesized by Knoevenagel condensation and they have been characterized with NMR, UV-visible and photoluminescence study. The electrolumnescent devices have been fabricated as typical single-layer devices consisting of ITO/polymer film/Al. The polymer films consist of a host polymer, poly(N-vinylcarbazole) which transport holes, a electron transporting material, 2-(4-biphenylyl)-5-(4-tert-butylphenyl) 1,3,4- oxadiazole (PBD), and the dopants, DCM derivatives. The device in which the concentration of dopant, (2,6-Bis{2-[4-(dibutylamino)phenyl]vinyl}-4H-pyran-4-ylidene)methane-1,1-dicarbonitrile (DCM2NBu), is 5 wt%, shows the pure red emission with the CIE coordinate, (0.66, 0.33), and the maximum emissive wavelength, 643 nm. The turn-on voltage of the device is $1.4×10^{8} V/m$.한국과학기술원 : 화학과

유기 발광 재료의 합성 및 특성에 관한 연구

학위논문(박사) - 한국과학기술원 : 화학과, 2004.2, [ v, 100 p. ]Generally, OLEDs are thin-film multi-layer structures composed of a hole-transporting, an emitting, and an electron-transporting material sandwiched between two electrodes, which result in a good charge balance of electrons and holes. Moreover, the buffer layer was inserted between ITO and hole-transporting layer to lower the operating voltage. In this thesis, the fluorene-based poly(iminoarylene)s with triarylamine unit were simply synthesized from palladium-catalyzed polycondensation of 2,7-dibromo-9,9-di-n-alkyllfluorene with primary amines such as aniline and p-toluidine. The polymers with high molecular weight were obtained and were thermally stable. The HOMO levels of the polymers (~ -5.1 eV) were close to the work function of ITO. Organic light-emitting diodes (OLEDs) of the form ITO/polymer/TPD/Alq3_/LiF/Al showed lower turn-on voltage ($V_T$ = 2.2V), the enhanced efficiency, and the higher maximum luminance at the higher current density (PFA1: 12370cd/㎡ at 427mA/㎠) than those of the device without polymer ($V_T$ = 3.6V, 5790cd/㎡ at 233mA/㎠). It is expected that these polymers can be used as a buffer layer in OLEDs. For full color displays, red, green and blue OLEDs should have high luminance, high efficiency, appropriate chromaticity, and long lifetimes. The performances of green and blue OLEDs have been improved up to the requirements of practical applications, but red OLEDs continue to exhibit poor color purity and low efficiency. First, the bis-condensed 4-(dicyanomethylene)-2-methyl-6-[p-(dimethylamino)styryl]-4H-pyran (DCM) derivatives are introduced as a new class of red dye for OLEDs. They showed more red-shifted emission than the mono-substituted DCM derivatives and the emission maxima increased as the electron-donating ability of the aromatic donor group increased. On the basis of these results, red OLEDs were fabricated with bis-condensed DCM derivatives as red dopants. For a device of configuration with ITO/TPD/$Alq_3$ :DADB (5.2wt%)/$Alq...한국과학기술원 : 화학과