• Korean Journal of Optics and Photonics
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• v.24 no.6
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• pp.311-317
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• 2013

It was reported in Nature and the Wall Street Journal on June 20th, 2012 that scientists at Duke university have developed a gigapixel camera, capable of over 1,000 times the resolution of a normal camera. According to the reports, this super-resolution camera was motivated by the need of US military authorities to surveil ground and sky. We notice the ripple effect of this technology has spread into the area of national defense and industry, so that this research has started to realize the super-resolution camera as a frontier research topic. As a result, we can understand the optical structure of a super-resolution camera's lens system to be composed of a front, monocentric objective of a single lens plus 98 rear, multiscale camera lenses. We can also obtain the numerical ranges of specification factors related to the optical structure, such as the diameter of the aperture, and the focal length.

• Bulletin of the Korean Chemical Society
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• v.28 no.11
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• pp.1958-1962
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• 2007

The title complex, Ir(H)(CO)(PEt3)2(η 2-C60) (2), has been prepared by the reaction of excess C60 (4 equiv) with a tetrairidium complex Ir4(CO)8(PEt3)4 (1) in refluxing chlorobenzene in 40% yield as green crystals. Compound 2 has been characterized by cyclic voltammetry (CV), spectroscopic methods (mass, IR, 1H and 31P NMR), and a single crystal X-ray diffraction study. The molecular structure reveals that the iridium atom of 2 is coordinated by two axial ligands of a hydrogen atom and a carbonyl group, and three equatorial ligands of two phosphorus atoms and an η 2-C60 moiety. The CV study exhibits three reversible one-electron redox waves for the successive reductions of 2, together with additional four redox waves due to free C60 reductions, which was formed by decomposition of 2 in the reduced states. The three reversible redox waves of 2 are shifted to more negative potentials by ca. 270 mV compared to free C60, reflecting both metal-to-C60 π-back-donation and the electron-donating nature of the two phosphorus ligands.

• Bulletin of the Korean Chemical Society
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• v.34 no.1
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• pp.167-173
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• 2013

A series of highly efficient red phosphorescent heteroleptic iridium(III) complexes 1-6 containing two cyclometalating 2-(2,4-substitued phenyl)quinoxaline ligands and one chromophoric ancillary ligand were synthesized: (pqx)$_2Ir$(mprz) (1), (dmpqx)$_2Ir$(mprz) (2), (dfpqx)$_2Ir$(mprz) (3), (pqx)$_2Ir$(prz) (4), (dmpqx)$_2Ir$(prz) (5), (dfpqx)$_2Ir$(prz) (6), where pqx = 2-phenylquinoxaline, dfpqx = 2-(2,4-diflourophenyl)quinoxaline, dmpqx = 2-(2,4-dimethoxyphenyl)quinoxaline, prz = 2-pyrazinecarboxylate and mprz = 5-methyl-2-pyrazinecarboxylate. The absorption, emission, electrochemical and thermal properties of the complexes were evaluated for potential applications to organic light-emitting diodes (OLEDs). The structure of complex 2 was also determined by single-crystal X-ray diffraction analysis. Complex 2 exhibited distorted octahedral geometry around the iridium metal ion, for which 2-(2,4-dimethoxyphenyl)quinoxaline N atoms and C atoms of orthometalated phenyl groups are located at the mutual trans and cis-positions, respectively. The emission spectra of the complexes are governed largely by the nature of the cyclometalating ligand, and the phosphorescent peak wavelengths can be tuned from 588 to 630 nm with high quantum efficiencies of 0.64 to 0.86. Cyclic voltammetry revealed irreversible metal-centered oxidation with potentials in the range of 1.16 to 1.89 V as well as two quasi-reversible reduction waves with potentials ranging from -0.94 to -1.54 V due to the sequential addition of two electrons to the more electron-accepting heterocyclic portion of two distinctive cyclometalated C^N ligands.

• Membrane and Water Treatment
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• v.7 no.3
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• pp.209-221
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• 2016

As a highly hydrophilic fibrillar mineral in nature, attapulgite (ATP) is a promising new additive for preparation of ultrafiltration (UF) hybrid membrane. In this work, ATP particles, which were grafted with a new Gemini surfactant of Ethyl Stearate-di(octadecyl dimethyl ammonium chloride) to detach the crystal bundles to single crystal and enhance the uniform dispersion in an organic polymer matrix, were incorporated into poly(vinylidene fluoride) (PVDF) matrix, and PVDF/Gemini-ATP hybrid membranes for adsorptive removal of Ni(II) ions from aqueous solution were prepared via a phase inversion method. Chemical composition, crystalization and morphology of the modified ATP were characterized by Fourier transform infrared spectroscopy (FTIR), Transmission electron microscope (TEM) and X-ray diffraction (XRD), respectively. The morphology of the hybrid membrane was characterized by Scanning electron microscopy (SEM), the performance of permeability, hydrophilicity and adsorption of Ni(II) ions were studied, and the adsorption kinetics of the PVDF/ATP hybrid membranes were particular concerned. The results showed that the hybrid membrane displayed a good thermal stability and hydrophilicity. Comparing with PVDF membrane, the hybrid membrane possessed good adsorption capacity for Ni(II) ions, and the adsorption kinetics fit well with Lagergren second-order equation.

• Journal of the Korean Society of Food Culture
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• v.9 no.4
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• pp.355-367
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• 1994

This study aims at exploring the nature of the traditional Korean wines brewed throughout the Southern Region of Korea-Chulla-do, Kyungsang-do and Cheju-do describing their varieties and brewing methods and also comparing the similarities and differences of their features. When compared with the wines produced in the Central Region, the Southern varieties are very fastidious and complex in their brewing methods, which in turn show a wide range of diversity. First of all, all the 29 kinds of wines investigated, not a single one shows any resemblance to any one of the remaining, each exhibiting peculiar and particular characteristic features of its own. Especially, the distilling methods demonstrate very complex processes. Secondly, the majority of the Southern spirits are made from grains, added with fragrant flavor of pine tree, wormwood, chrysanthemum leaves and other medicine herbs such as Chinese matrimony vine and tankui. Thirdly, they are brewed with yeast made from wheat into kodupap(steamed rice) type of spirits, emerging as in the form of blended liquor. Fourthly, in brewing, different fermenting temperature and duration are required. Typewise, the temperature required for the basic spirit is $15{\sim}20^{\circ}C\;or\;25{\sim}30^{\circ}C$ : in the case of blended secondarily fermented liquor, from the minimum of $0{\sim}5^{\circ}C$ to the maximum of $75{\sim}80^{\circ}C$. The brewing duration is $3{\sim}5$ days for the basic spirits. In some cases, from the minimum of 3 days to the maximum of 100 days are consumed for fermenting. Fifthly, the wine extraction gadgets are yongsu (wine strainer), the sieve, filter paper, Korean traditional paper, the utilization of which implies that the brewers endeavor to observe and preserve the traditional and indigenous methods of wine making.

• KSBB Journal
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• v.15 no.5
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• pp.537-540
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• 2000

In developing a HPLC purification process, it was hoped that a single chromatographic system would be sufficient to abtain pure paclitaxel in high yield. However, no such system was found, due in part to the complex taxoid profile of crude paclitaxel and to the rigorous nature of the product specification. A two step HPLC purification was adopted using reverse-phase separation on C(sub)18 as a first step, and normal-phase separation on silica as the final polishing step. Impurity profiles were established and maintained for paclitaxel, which identified and quantified each impurity observed in purified paclitaxel from these two steps, all impurities at or above 0.1% were identified. Results provide information for improving the quality control of paclitaxel production.

• Korean Journal of Construction Engineering and Management
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• v.7 no.4 s.32
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• pp.91-99
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• 2006

The purpose of this study is propose an Artificial Neural Network(ANN) model for the construction estimate of the public educational facility at conceptual stage. The current method for the preliminary cost estimate of the public educational facility uses a single-parameter which is based on basic criteria such as a gross floor area. However, its accuracy is low due to the nature of the method. When the difference between the conceptual estimate and detailed estimate is huge, the project has to be modified to meet the established budget. Thus, the ANN model is developed by using multi-parameters in order to estimate the project budget cost more accurately. The result of the research shows 6.82% of the testing error rates when the developed model was tested. The error rates and the error range of the developed model are smaller than those of the general preliminary estimating model at conceptual stage. Since the proposed ANN model was trained using the detailed estimate information of the past 5 years' school construction data, it is expected to forecast the school project cost accurately.

• Analytical Science and Technology
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• v.16 no.3
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• pp.206-211
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• 2003

The DC polarograms of some rare earth elements have been investigated in various pH solution and electrolytes. Samarium ion has two well-defined reduction waves at -1.75 V and -1.95 V in 0.1 M NaCl solution and those are a diffusion controlled in nature. Europium and ytterbium ions give also two step reduction waves at -0.75 V and -1.95 V for europium and -1.45 V and -2.00 V for ytterium in $(C_2H_5)_4NCl$ solution. On the other hand, lantanium and neodium ions show a single reduction wave at -1.75 V. The differences of half wave potentials between europium, ytterium and samarium ions make it possible to determine each ions in the mixed solution sponteniously. In case of europium ion, the stability constants for the complexs of $Eu^{3+}$-EDTA and $Eu^{3+}$-DTPA are evaluated.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.5_6
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• pp.280-289
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• 2003

Deadlock recovery-based routing algorithms in wormhole networks have gained attraction due to low hardware complexity and high routing adaptability Progressive deadlock recovery techniques require a few dedicated resources to transmit deadlocked packets rather than killing them. Selection of deadlocked packets is primarily based on time-out value which should be carefully determined considering various traffic patterns or packet length. By its nature, current techniques using time-out accompany unignorable number of false deadlock detections especially in a heavy-loaded network or with long packet size. Moreover, when a deadlock occurs, more than one packet may be marked as deadlocked, which saturate the resources allocated for recovery. This paper proposes more accurate deadlock detection scheme which does not make use of time-out to declare deadlock. The proposed scheme reduces the probability to detect false deadlocks considerably. Furthermore, a single message is selected as deadlocked for each cycle of blocked messages, thereby eliminating recovery overheads.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.11
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• pp.1543-1550
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• 2015

Ferroresonance is a non-linear vibrational phenomenon that is generated by the electrical interaction of the inductance component with the capacitor component of a certain capacitance as the device of the inductance component such as a transformer is saturated due to the degradation, the waveform distortion of current and voltage, and the oscillation of overcurrent and overvoltage in a system. Recently, ferroresonance was generated from the waveform distortion of current and voltage, or the overvoltage or undervoltage phenomenon caused by the nature of an electrical power system and design technology of the transformer in the three phase transformer system. Hence, in general, ferroresonance analyzed by converting to the LC equivalent circuit. However, in general, the aforementioned analytical method only applies to the resonance phenomenon that is generated by the interaction of the capacitance of bussbar and grounding, and switching as the capacitor component with PT and the transformer as the inductance component in a system. Subsequently, the condition where ferroresonance was generated since overvoltage was supplied as line voltage to the phase voltage and thus the iron core is saturated due to the interconnection between grounded and ungrounded systems could not be analyzed when single phase PT was connected in a ${\Delta}$/Y connection system. In this study, voltage swell in the configuration of grounded circuit of a step-up transformer with the ${\Delta}-{\Delta}$ connection linked to PT for control power and the ferroresonance generated by overvoltage when the line voltage of the ${\Delta}-{\Delta}$ connection was connected to the phase voltage of the grounded Y-Y connection were analyzed using PSCAD / EMTDC through the failure case of the transformer caused by ferroresonance in the system with the ${\Delta}-{\Delta}$/Y-Y connection, and subsequently, the preventive measure of ferroresonance was proposed.