• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.9
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• pp.1048-1057
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• 2012

In this paper, a new compact dual-band unequal power divider is suggested. Instead of the quarter wavelength transmission line(TX-line)s for the branches of the conventional Wilkinson's power divider, we use composite right- and left-handed(CRLH) phase-shift lines and can reduce the physical length. With the non-linear dispersion of the meta-meterial, each branch in the proposed divider is designed to have $+90^{\circ}$ and $-90^{\circ}$ at $f_1$ and $f_2$ respectively. To validate the proposed method, the performances of the circuit and full-wave simulation results are shown with the CRLH dispersion curve. The measurement results are compared with the simulation results. Also, the size reduction effect by the proposed scheme is addressed.

• Korean journal of applied entomology
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• v.25 no.2 s.67
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• pp.77-83
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• 1986

From the result Of survey (4th Aug.${\sim}$20th Aug.1986) for the moths in the area of the Civilian Control Line neighboring D.M.Z., in total 89 species belonging 21 families were identified. Among them 4 species; Nemophora askoldetla (M.), Dichrerampha atbistriana K., Grapholita dimorpha K. and Epiblema sugii K. are reported for the first rime from Korea.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.2
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• pp.317-326
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• 2016

In this paper, a logic eFuse (electrical Fuse) OTP (One-Time Programmable) memory IP (Intellectual Property) using only logic transistors to reduce the development cost and period of OTP memory IPs is designed. To secure the reliability of other IPs than the OTP memory IP, a higher voltage of 2,4V than VDD (=1.5V) is supplied to only eFuse links of eFuse OTP memory cells directly through an external pad FSOURCE coming from test equipment in testing wafers. Also, an eFuse OTP memory cell of which power is supplied through FSOURCE and hence the program power is increased in a two-dimensional memory array of 128 rows by 8 columns being also able to make the decoding logic implemented in small area. The layout size of the designed 1kb eFuse OTP memory IP with the Dongbu HiTek's 110nm CIS process is $295.595{\mu}m{\times}455.873{\mu}m$ ($=0.134mm^2$).

• Korean Chemical Engineering Research
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• v.53 no.3
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• pp.276-281
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• 2015

Nanostructured $TiO_2-SiO_2$ materials have widely been used as anti-reflecting coating, optical-chemical sensors and catalysts because of their superior optical and thermal properties as well as chemical durability. Web type $SiO_2$ microfibers with nano-crystalline $TiO_2$ were prepared by electrospinning of Ti-PCS mixed solution and oxidation controlled heat-treatment, rather simple than sol-gel process. Nano-crystalline anatase phase were formed for the heat-treatment up to $1200^{\circ}C$ and they were finely dispersed in the amorphous $SiO_2$ matrix.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8B
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• pp.797-804
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• 2009

Recently, SIP(Session Initiation Protocol) is used to set up and manage sessions for multimedia applications such as VoIP(Voice over IP) and IMS(IP Multimedia Subsystem). However, because SIP operates over the Internet, it is exposed to pre-existed internet security threats such as service degradation or service disruptions. Multimedia applications which are delay sensitive even suffers more from the threats mentioned above. The proposed methods so far to detect SIP INVITE flooding are CUSUM(Cumulative Sum), Hellinger distance and adaptive threshold, but among methods only take normal state into consideration. So, it is not capable of adapting the condition of the network congestion which are dynamically changing. In this paper, SIP INVITE flooding detection algorithm considering network congestion which enables efficient detections of such attacks is proposed. The proposed algorithm is expected to detect other types of attacks such as BYE and CANCEL more precisely compared to other methods.

• Korean journal of applied entomology
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• v.45 no.2 s.143
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• pp.131-137
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• 2006

Twenty-six species of the subfamily Herminiinae were recognized from the lepidopteran surveys in Mt. Changbai (China) during 1999-2004. Among them, six species are reported for the first time from China: Paracolax fascialis (Leech), P. fentoni (Butler), Polypogon gryphalis Herrich-Sch$\"{a}$ffer, Sinarella japonica (Butler), S. punctalis (Herz), and S. cristulalis (Staudinger): and seven species are new to Mt. Changbai: Hadennia incongruens (Butler), Paracolax tristalis (Fabricius), Paracolax trilinealis (Bremer), Idia quadra (Graeser), Hydrillodes morosa (Butler), Herminia grisealis [Denis & Schifferm$\"{u}$ller], and Sinarella nigrisigna (Leech). For the six newly reported species from China, taxonomical notes, color images of adults, and figures of the male or the female genitalia are provided.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.687-690
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• 2015

For research and development of Silicon Carbide (SiC) mirrors, the Korea Astronomy and Space Science Institute (KASI) and National Optical Astronomy Observatory (NOAO) have agreed to cooperate and share on polishing and measuring facilities, experience and human resources for two years (2014-2015). The main goals of the SiC mirror polishing are to achieve optical surface figures of less than 20 nm rms and optical surface roughness of less than 2 nm rms. In addition, Green Optics Co., Ltd (GO) has been interested in the SiC polishing and joined the partnership with KASI. KASI will be involved in the development of the SiC polishing and the optical surface measurement using three different kinds of SiC materials and manufacturing processes (POCO$^{TM}$, CoorsTek$^{TM}$ and SSG$^{TM}$ corporations) provided by NOAO. GO will polish the SiC substrate within requirements. Additionally, the requirements of the optical surface imperfections are given as: less than 40 um scratch and 500 um dig. In this paper, we introduce the international collaboration and interim results for SiC mirror polishing and development.

• Journal of the Korean Ceramic Society
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• v.50 no.4
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• pp.301-307
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• 2013

SiC hollow fiber was fabricated by curing, dissolution and sintering of Al-PCS fiber, which was melt spun the polyaluminocarbosilane. Al-PCS fiber was thermally oxidized and dissolved in toluene to remove the unoxidized area, the core of the cured fiber. The wall thickness ($t_{wall}$) of Al-PCS fiber was monotonically increased with an increasing oxidation curing time. The Al-PCS hollow fiber was heat-treated at the temperature between 1200 and $2000^{\circ}C$ to make a SiC hollow fibers having porous structure on the fiber wall. The pore size of the fiber wall was increased with the sintering temperature due to the decomposition of the amorphous $SiC_xO_y$ matrix and the growth of ${\beta}$-SiC in the matrix. At $1400^{\circ}C$, a nano porous wall with a high specific surface area was obtained. However, nano pores grew with the grain growth after the thermal decomposition of the amorphous matrix. This type of SiC hollow fibers are expected to be used as a substrate for a gas separation membrane.

• Journal of Sensor Science and Technology
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• v.2 no.1
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• pp.87-94
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• 1993

CdS and Se thin films were deposited on slide glass by EBE method respectively and surface morphology, crystal structure, electrical and optical properties were investigated by substrate temperature and annealing. The deposited CdS film was well fabricated with cubic structure at substrate temperature of $150^{\circ}C$. Se film was deposited with noncrystal structure until substrate temperature of $100^{\circ}C$, but Se film was grown with monoclinic structure at substrate temperature of $150^{\circ}C$. And so, after annealing at $150^{\circ}C$ for 15min, noncrystalline Se was proved to be hexagonal structure. Finally, the maximum output of Se/CdS heterojunction at 5000 lux was 4 $mW/cm^{2}$ and maximum spectral sensitivity was represented at 585nm.

• Journal of Korea Foundry Society
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• v.34 no.5
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• pp.170-178
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• 2014

Using the Gleeble test, the effects of [Mn/S] ratios and the presence of sulfides on the high-temperature fracture morphology of heavy-section steel castings were analysed via the observations of the microstructures. The specimens for which the [Mn/S] ratio was in the range of 60~80 showed a ductile fracture morphology with an area reduction of more than 60%, while some specimens with similar [Mn/S] ratios showed a brittle fracture morphology with an area reduction of 0.0% due to the liquidation of sulfides at the grain boundary. The fracture morphology was classified into three types in the Gleeble high-temperature tensile test specimens. The first type showed dimple formation at the grain boundary, the formation of globular MnS sulfides, and plastic deformation of sulfides at an elevated temperature, indicating a needle-point type of ductile fracture with area reductions of 96.0~97.8%. The second type was a knife-edge type brittle fracture with an area reduction of 0.0% due to the film-type liquidation of sulfides at the grain boundary, band-type liquidation, and the liquidation of a terraced nipple pattern. The third type was the typical ductile fracture with an area reduction of 31.3~81.0%, in accordance with the mixture of dimples with in the grains and terraced nipple pattern at the grain boundary.