• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.04a
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• pp.33-34
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• 2007

카본과 BN의 합성조건을 제어하여 고경도 상과 저경도 상을 다층박막화하기 위하여 시편에 인가하는 바이어스 전압을 조절하여 박막을 합성하였다. 합성된 다층박막은 카본의 경우 흑연상을 많이 함유한 단일층 박막과 유사한 경도와 탄성계수를 보였으나 마찰계수는 $2{\sim}3$배 개선되었다. BN의 경우에도 2층박막화된 박막에서 FTIR분석 결과로는 50%이상의 c-BN이 합성된 것으로 나타났으며, 마모특성도 c-BN박막과 유사하였다.

• Current Optics and Photonics
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• v.5 no.6
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• pp.672-679
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• 2021

We propose a high-speed layer-based algorithm for synthesizing computer-generated holograms (CGHs), featuring sparsity-based image segmentation and computational parallelism. The sparsity-based image segmentation of layer-based three-dimensional scenes leads to considerable improvement in the efficiency of CGH computation. The efficiency enhancement of the proposed algorithm is ascribed to the field localization of the fast Fourier transform (FFT), and the consequent reduction of FFT computational complexity.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.351.1-351.1
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• 2002

Heterocyclic compounds with oxygen atoms are known to have potent biological effect. The flavonoids. isoflavonoids. and coumarins which form the bulk of these compounds are very polar and have limited use as drugs which have to pass through membranes. The non-polar property is increased by exchange oxygen to selenium as a part of heterocyclic compound. Our group is focused on synthesizing selenoheterocyclic compound with the above property. (omitted)

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.65.1-65.1
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• 2003

Natural benzo[c]phenanthridine and protoberberine alkaloids which have been attractive to synthetic organic chemists and biochemists over the last 2 decades since such compounds have shown interesting biological properties such as antitumor, antiviral and antimicrobacterial activities. For the systematic research on these alkaloids, several total syntheses of these alkaloids have been reported. However, the bulk of reported benzo[c]phenanthridine synthetic studies to date have involved multistep sequences for assembly of the target molecules as well as lack of generality for synthesizing substituted molecules. (omitted)

• Journal of the Korean Society of Safety
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• v.36 no.3
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• pp.81-81
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• 2021

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.2519-2525
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• 2014

WeI have studied the process for synthesizing porous silica with a specific surface area of minimum $800m^2/g$ by adding surfactant [Poly Etylene Glycol(PEG) and Hydroxy Propyl Cellulose(HPC)] to the sol-gel reaction between sodium silicate and hydrochloric acid. NaCl, the by-product of the sol-gel reaction, was water cleaned and removed; when 200 ml of water was used to clean 50 g of silica gel, NaCl remaining in the silica gel was reduced to maximum 0.81wt%. The appropriate level of surfactant for silica gel synthesizing proved to be below 5%. As a result of the experiment, for the silica synthesized by adding surfactant of HPC(2.5%)+PEG(2.5%), the surfactant area was $860m^2/g$ and grain size was $20-50{\mu}m$. From this study, we have concluded that it is of industrial significance that specific surface area is improved and silica of a regular grain size is obtained just by adding surfactant in the gel process or drying process of silica.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.30 no.5
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• pp.194-199
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• 2020

By controlling the composition of the metal-oxide nanosheet having a two-dimensional layered crystal structure, material properties and application can be extended. In this study, the composition of the nanosheet could be expanded from pure composition to doping composition by successfully synthesizing the TiO₂ nanosheet doped with Nb. Specifically, the doping composition was designed when synthesizing the layered metal oxide as a starting material (K_0.8Ti_1.73-xNb_xLi_0.27O₄, x = 0, 0.03, 0.07) and chemical exfoliation was performed. By doing this, it was possible to obtain the Nb-doped TiO_y ultrathin nanosheet. The size of the nano sheet was 2 ㎛ or less based on the long length in the x-y direction, and the thickness was about 1 nm. Nb-doping was confirmed by XRD and SEM-EDS analysis.

• Journal of KIISE
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• v.44 no.9
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• pp.986-991
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• 2017

In this paper, we present a method for synthesizing imperative programs from input-output examples. Given (1) a set of input-output examples, (2) an incomplete program, and (3) variables and integer constants to be used, the synthesizer outputs a complete program that satisfies all of the given examples. The basic synthesis algorithm enumerates all possible candidate programs until the solution program is found (enumerative search). However, it is too slow for practical use due to the huge search space. To accelerate the search speed, our approach uses code optimization and avoids unnecessary search for the programs that are syntactically different but semantically equivalent. We have evaluated our synthesis algorithm on 20 introductory programming problems, and the results show that our method improves the speed of the basic algorithm by 10x on average.

• Development and Reproduction
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• v.20 no.3
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• pp.197-205
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• 2016

Adipose tissue is one of the major endocrine gland. More recently, local production of steroids in adipocytes differentiated from mouse 3T3-L1 cell-line was reported. We hypothesized that rat adipocytes have steroidogenic machinery and the expression patterns of the components might be differentially regulated, depending on the distribution and sex. To verify this hypothesis, we collected the adipose tissues depot-and sex-specifically at postnatal day (PND) 30, and performed quantitative RT-PCRs. In overall aspects, the abundances of the transcripts were lower in the brown adipose of both sexes. $3{\beta}-HSD$ transcript levels in female abdominal and reproductive adipose, CYP17 transcript levels in female reproductive adipose, $17{\beta}-HSD$ transcript levels in female abdominal and reproductive adipose, and CYP19 transcript levels in female abdominal adipose were significantly lower than those of male counterparts. Similar to steroidogenic factors, the abundance of the $ER-{\alpha}$ transcripts were generally lower in the brown adipose of both sexes. $ER-{\beta}$ transcripts were more abundant in male white adipose depots than their female counterparts. The levels of LHR transcripts in female reproductive adipose were significantly higher than those of male counterpart. In conclusion, our study demonstrated that the expressions of steroidogenesis-related genes were depot- and sex-specifically occurred in the immature male and female rat adipose tissues. Our study suggested that the adipose tissues are not only targets but de novo synthesizing sites of sex steroid(s), though the synthesizing activities could be much less than in gonads. Further researches in this field will be helpful for understanding the adipose physiology and for medical application such as sex-specific steroid supplement therapies for older populations.

• Journal of the Korean Ceramic Society
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• v.40 no.4
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• pp.365-370
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• 2003

The phase development process of $Ba_2$ $Ti_{9}$ $O_{20}$ ceramics is not clearly known and frequently accompanies second phases which deteriorate dielectric properties. In synthesizing $Ba_2$ $Ti_{9}$ $O_{20}$ ceramics, in order to trace the reaction sequence during conventional solid-state reaction in BaO-Ti $O_2$ system, different barium sources of BaC0$_3$ and BaTi0$_3$ precursor were used as starting materials. From the analysis of XRD patterns, different secondary phases could be identified depending on the barium source used, which might mean that the equilibrium phases in BaO-Ti $O_2$ system are very difficult to be synthesized. Because the BaTi0$_3$ precursor provides short diffusion paths of ions, the system revealed less secondary phases during solid state reaction. In synthesizing BaO-xSm$_2$0$_3$-4.5Ti0$_2$ system using different barium sources, different secondary phases were developed also. Microstructure and dielectric properties were examined and discussed in terms of secondary phase development.