http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Energy Transfer Between Ce^3+ and Tb^3+ Ions in (Gd_1-x-y Tb_xCe_y)₂(MoO₄)₃Crystals
KIM, Junghwan,KIM, Sung Chul,YU, Yun Sik,KIM, Hongki,MOON, Byung Kee,KIM, Sun Il 동의대학교 기초과학연구소 1994 基礎科學硏究論文集 Vol.4 No.1
The energy transfers Tb^3+(^5D₃)→Ce^3+(5d¹) and Ce^3+(5d¹)→Tb^3+(5^D₄) in (Gd_1-x-y Tb_xCe_y) crystals were studied using time-resolved spectroscopy. It was found that the energy transfer Tb^3+(^5D₃)→Ce^3+(5d¹) occurs via the dipole-dipole interaction. The critical distance of the energy transfer was obtained as 13.2Å at 30 K. At room temperature, the strong 5^D₃-5^D₄cross-relaxation of Tb^3+ ions takes place simultaneously with the energy transfer Tb^3+(^5D₃)→Ce^3+(5d¹). The critical distance of cross relaxation in these crystal was 11.6Å at room temperature. By measuring lifetimes and emission intensities, the efficiencies of the energy transfers from Tb^3+(5^D₃) to Ce^3+ and from Ge^3+ to Tb^3+(5^D₄) were calculated.
Coleridge's Conversation Poems : Romantic Likening and the Vision of One Life
Hongki Kim 21세기영어영문학회 2010 영어영문학21 Vol.23 No.2
Coleridge’s Conversation Poems: Romantic Likening and the Vision of One Life Hongki Kim (Kwangwoon University) In his conversation poems, Samuel Taylor Coleridge is looking at how a part can be related to a whole. In his two conversation poems, The Eolian Harp and This Lime-Tree Bower My Prison in particular Coleridge explores the mysteries of the One Life postulating visible things in nature are a symbolic text in which he can read figures of Romantic likening. Nature in Coleridge's episteme does not only provides its physical beauty but its encounter with the self transposes him to a cosmic communion with the mysterious order of the One Life. Subject and object participate together in the Coleridgean Romantic organicism and his poems are a record of the soul's adventures among Romantic metaphors.
Risk-informed Emergency Response Training for Backdraft in Nuclear Power Plants
Mihyun Kim,Wonkook Kim,Hongki Kim,Jungman Kim,Sunhong Yoon,Jangwon Choi,Heemoon Kim 한국화재소방학회 2023 International Journal of Fire Science and Engineer Vol.37 No.3
Research has been conducted for developing fire evacuation and response training programs for nuclear power plant (NPP) application. Among numerous fire scenarios that may occur in an NPP environment, three different points of origin for a fire were selected for the program based on a risk-informed approach: switchgear room, main control room, and safety injection pump room. Fire outcomes were predicted for these scenarios via numerical modeling and the results were incorporated into the newly developed fire evacuation and response training program for the APR1400, Korea’s next-generation NPP model. The switchgear room fire scenario was found to have the most potential for backdraft to occur during manual fire response following automatic gaseous fire suppression system activation. The emergency response manual does discuss this possible backdraft occurrence; however, the guidance to avoid injuries is qualitative, such as to be cautious of backdrafts and wait a sufficient amount of time after opening a door before entering the. In this study, backdraft phenomenon that may occur from a switchgear room fire was numerically examined using the recent version of the Fire Dynamics Simulator to develop an appropriate timeline to be implemented in the fire evacuation and response training program. Based on the findings, the following guidance is provided: (1) backdraft can only occur when the fire originates in the space near the door; (2) wait at least 10 minutes after opening the door before entering the room; (3) watch for rapid smoke production, as this may be an antecedent phenomenon of backdraft; and (4) when smoke production increases rapidly, leave the room as soon as possible to avoid being caught within the deflagrating flames from a backdraft.
Stacking Structures of Few-Layer Graphene Revealed by Phase-Sensitive Infrared Nanoscopy
Kim, Deok-Soo,Kwon, Hyuksang,Nikitin, Alexey Yu.,Ahn, Seongjin,Martí,n-Moreno, Luis,Garcí,a-Vidal, Francisco J.,Ryu, Sunmin,Min, Hongki,Kim, Zee Hwan American Chemical Society 2015 ACS NANO Vol.9 No.7
<P>The stacking orders in few-layer graphene (FLG) strongly influences the electronic properties of the material. To explore the stacking-specific properties of FLG in detail, one needs powerful microscopy techniques that visualize stacking domains with sufficient spatial resolution. We demonstrate that infrared (IR) scattering scanning near-field optical microscopy (sSNOM) directly maps out the stacking domains of FLG with a nanometric resolution, based on the stacking-specific IR conductivities of FLG. The intensity and phase contrasts of sSNOM are compared with the sSNOM contrast model, which is based on the dipolar tip–sample coupling and the theoretical conductivity spectra of FLG, allowing a clear assignment of each FLG domain as Bernal, rhombohedral, or intermediate stacks for tri-, tetra-, and pentalayer graphene. The method offers 10–100 times better spatial resolution than the far-field Raman and infrared spectroscopic methods, yet it allows far more experimental flexibility than the scanning tunneling microscopy and electron microscopy.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2015/ancac3.2015.9.issue-7/acsnano.5b02813/production/images/medium/nn-2015-02813x_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn5b02813'>ACS Electronic Supporting Info</A></P>
Kim, Junyoung,Xing, Jingchao,Nam, Hyeong Soo,Song, Joon Woo,Kim, Jin Won,Yoo, Hongki Optical Society of America 2017 Optics letters Vol.42 No.3
<P>Micro-optical coherence tomography (mu OCT) is an advanced imaging technique that acquires a three-dimensional microstructure of biological samples with a high spatial resolution, up to 1 mu m, by using a broadband light source and a high numerical aperture (NA) lens. As high NA produces a short depth of focus (DOF), extending the DOF is necessary to obtain a reasonable imaging depth. However, due to the complexity of optics and the limited space, it has been challenging to fabricate endoscopic mu OCT, which is essential for clinical translation. Here, we report an endoscopic mu OCT probe with an extended DOF by using a binary phase spatial filter. The imaging results from latex beads demonstrated that the mu OCT probe achieved an axial resolution of 2.49 mu m and a lateral resolution of 2.59 mu m with a DOF extended by a factor of 2. The feasibility of clinical use was demonstrated by ex vivo imaging of the rabbit iliac artery. (C) 2017 Optical Society of America.</P>
Kim, Hongki,Lee, Yoon Ho,Lyu, Taecheon,Yoo, Jong Heun,Park, Taiho,Oh, Joon Hak The Royal Society of Chemistry 2018 Journal of materials chemistry. A, Materials for e Vol.6 No.37
<P>The poor oxidative stability of tin-based perovskites has been an obstacle to their widespread implementation in high-performance solar cells. Herein, quasi-two-dimensional (quasi-2D) tin-based perovskite solar cells are fabricated with significantly improved performance and stability, by introducing an additional formamidinium thiocyanate (FASCN) additive into quasi-2D tin-based perovskites. The incorporation of the FASCN additive greatly prevents quasi-2D tin-based perovskites from oxidation during film formation, through strong chemical interactions with the tin component (Sn<SUP>2+</SUP>). Moreover, it results in a coarser perovskite grain and a higher degree of crystallinity in the out-of-plane direction, leading to enhanced optoelectronic performance of quasi-2D tin-based perovskites. The best-performing tin-based perovskite solar cell shows an efficiency of 8.17% under reverse scan with a steady-state efficiency of 7.84% at a maximum power point (MPP), while retaining over 90% of its initial efficiency after 1000 hours in a glovebox filled with nitrogen. These results demonstrate a versatile, yet simple methodology that can be applied to other lead-free perovskites suffering from poor oxidative stability.</P>
Hongki Yoo,Seungwoo Lee,Dongkyun Kang,Taejoong Kim,Daegab Gweon,Sukwon Lee,Kwangsoo Kim 한국정밀공학회 2006 International Journal of Precision Engineering and Vol.7 No.4
Confocal scanning microscopy is a measurement technique used to observe micrometer and sub-micrometer features due to its high resolution, nondestructive properties, and 3D surface profiling capabilities. The design, implementation, and performance test of a confocal scanning microscopy system are presented in this paper. A short-wavelength laser (405 ㎚) and an objective lens with a high numerical aperture (0.95) were used to achieve the desired high resolution, while the x-and y-axis scans were implemented using an acousto-optic deflector and galvanomirror, respectively. An objective lens with a piezo-actuator was used to scan the z-axis. A spatial resolution of less than 138 ㎚ was achieved, along with successful 3D surface reconstructions.