• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.13-14
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• 2013

Multiple output converters (MOCs) are widely used for applications which require various kinds of the output voltages due to its advantages in cost, volume, and efficiency. However, most of the MOCs developed so far can regulate only one output tightly and require as many secondary windings in the transformer as the number of the outputs. In this paper, a novel Time Division Multiple Control (TDMC) method to regulate all the outputs in high precision is proposed and applied to the double ended forward converter for the multiple battery charger. Additional benefit of the proposed topology is to require only one secondary winding in the transformer for all the outputs. The proposed converter can charge two different kinds of batteries or same kind of batteries in different state of charges (SOCs) by CC/CV mode independently with the even degree of tight regulation, thereby satisfying the ripple requirements for each battery.

• Textile Coloration and Finishing
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• v.24 no.3
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• pp.153-157
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• 2012

One of organic dye materials which have been long lasting investigated is rhodamine 6G dye series. This dye has been attracted with considerable interests due to the reason of its promising photochemical properties. In this study, a novel fluorescent dye compound based on rhodamine 6G derivative was synthesized through the reaction of rhodamine 6G hydrazide and indole-3-carboxaldehdyde. Absorption and fluorescent emission spectra of this dye were determined with the properties of solvatofluorochromism. Related electron energy states of the dye compound were also characterized by computational calculations.

• Journal of Microbiology and Biotechnology
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• v.30 no.1
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• pp.11-20
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• 2020

Quercetin and its derivatives are important metabolites that belong to the flavonol class of flavonoids. Quercetin and some of the conjugates have been approved by the FDA for human use. They are widely distributed among plants and have various biological activities, such as being anticancer, antiviral, and antioxidant. Hence, the biosynthesis of novel derivatives is an important field of research. Glycosylation and methylation are two important modification strategies that have long been used and have resulted in many novel metabolites that are not present in natural sources. A strategy for modifying quercetin in E. coli by means of glycosylation, for example, involves overexpressing respective glycosyltransferases (GTs) in the host and metabolic engineering for increasing nucleoside diphosphate sugar (NDP-sugar). Still others have used microorganisms other than E. coli, such as Streptomyces sp., for the biotransformation process. The overall study of the structural activity relationship has revealed that modification of some residues in quercetin decreased one activity but increased others. This review summarizes all of the information mentioned above.

• Journal of the Optical Society of Korea
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• v.15 no.3
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• pp.222-226
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• 2011

We demonstrated the feasibility of an amplified wavelength-division multiplexed passive optical network (WDM-PON) architecture based on broadband light source (BLS) seeded optical sources and a novel bidirectional reach extender. Our bidirectional reach extender could provide an amplification of both downstream and upstream signals as well as a BLS output for the upstream WDM signal generation. An error-free 1.25 Gb/s signal transmission over a 100-km long single-mode fiber was achieved in a bidirectional WDM-PON using BLS seeded reflective semiconductor optical amplifier (RSOA) sources.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.925-927
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• 2008

In order to improve the performance in green phosphorescent OLED devices, Merck has developed novel host and electron blocking materials. The newly developed host materials improve the device lifetime by a factor of 3. The newly developed electron blocking materials having not only electron but also exciton barrier properties increase the efficiency of the device by a factor of 1.4. Comparable results were achieved in phosphorescent red systems with further host materials.

• Bulletin of the Korean Chemical Society
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• v.31 no.9
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• pp.2467-2472
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• 2010

Twenty novel tetramic acid derivatives (E)-3-(1-(alkyloxyamino)ethylidene)-1-alkylpyrrolidine-2,4-diones were synthesized by the reaction of 3-(1-hydroxyethylidene)pyrrolidine-2,4-diones with O-alkyl hydroxylamines. The title compounds were confirmed by IR, $^1H$ NMR, MS and elemental analysis. The structure of compound 6r was further verified by X-ray diffraction crystallography. The bioassays showed that most of the title compounds exhibited noticeable herbicidal and fungicidal activities.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.113.1-113.1
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• 2014

Surface-enhanced Raman scattering (SERS) has long been projected as a powerful analytical technique for chemical and biological sensing applications. Pairing with portable Raman spectrometers makes the technique extremely appealing as real-time sensors for field application. However, the lack of reliable, uniform, low cost and ease-of-use SERS enhancement structures has prevented the wide adoption of this technique for general applications. We have discovered a novel hybrid structure based on the high-density and uniform arrays of gold nanofingers over a large surface area for SERS applications. The nanofingers are flexible and their tips can be brought together to trap molecules to mimic the biological system. We report here a rapid, simple, low-cost, and sensitive method of detecting trace level of food contaminants by using nanofinger chips based on portable SERS technique. We also present here the characterization of surface reaction of target molecules with our gold nanofinger substrates and the effect of nanofinger closing towards SERS performance. This new type of nano-structures can potentially revolutionize the medical and biologic research by providing a novel way to capture, localize, manipulate, and interrogate biological molecules with unprecedented capabilities.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.475-478
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• 2002

VA-LCDs is widely used for recent LCD productions owing to good viewing angle and high contrast. To apply for VA-LCDs, we have synthesized novel homeotropic alignment materials, which all generated high pretilt angles ($9^{\circ}$). The thermal stabilities of them were observed by thermogravimetric analysis (TGA). Transmittances of the NLC cell used the new alignment material were not changed before and after thermal annealing at $120^{\circ}C$ for 24hrs. In this work, the synthesis and alignment properties of new homeotropic alignment materials will be reported.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.125.1-125.1
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• 2011

After a short description of the observatory, this presentation will highlight some of the most recent scientific achievements based on CFHT observations and how they benefit from the current instrumentation and novel observing modes proposed to the CFHT users. We will then move to the mid-term future with the development of new spectroscopic capabilities (visible wide-field FTS or near-IR spectro-polarimetry) and the study of a novel wide-field imager in the visible using Ground-Layer AO to provide unprecedented image quality on a large field of view. As an option for the long-term future, the concept of a next generation 10-m class telescope to replace the current CFHT 3.6-m will be described. An emphasis will be given on how CFHT is slowly morphing into an Asia-Pacific Rim observatory and on the role the Korean community could play in such an endeavor, from immediate access to first-class astronomical data to partnering with other nations in exciting developments.

• Journal of the Optical Society of Korea
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• v.18 no.5
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• pp.485-494
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• 2014

A novel antenna with ellipsoid-paraboloid surfaces configuration is designed for matching the incident radial radiation fiber laser distribution for maximum transmission efficiency. The on-axial and off-axial defocus effects on the optical antenna system, resulting in energy loss, are analyzed in detail. Knowledge of the effects of those defocuses on beam divergence, aberration and antenna transmission efficiency is of great importance to the long range communication systems.