• Journal of Electrical Engineering and Technology
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• v.13 no.5
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• pp.2004-2010
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• 2018

We propose a small active antenna to receive Global Navigation Satellite System (GNSS) signals, i.e., Global Positioning System (GPS) L1 (1,575MHz) and Russian Global Navigation Satellite System (GLONASS) L1 (1,600 MHz) signals. A two-stage low-noise amplifier (LNA) with more than 27 dB gain is implemented in the bottom layer of a three-layer antenna package. In addition, a hybrid coupler is used to combine signals from pair of proximately coupled orthogonal feeds with $90^{\circ}$ phase difference to achieve the circular polarization (CP) characteristic. Three layers of high permittivity (${\varepsilon}_r=10$) substrates are stacked and effectively integrated to have a small dimension of $64mm{\times}64mm{\times}7.42mm$ (including both circuit and antenna). The reflection coefficient of the fabricated antenna at the target frequency is below -10 dB, the measured antenna gain is above 26 dBic and the measured noise figure is less than 1.4 dB.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1408-1409
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• 2007

In this paper, we developed a hybrid simulation model of carbon laser ablation under the Ar plasmas consisted of fluid and particle methods. Three kinds of carbon particles, which are carbon atom, ion and electron emitted by laser ablation, are considered in the computation. In the present modeling, we adopt capacitively coupled plasma with ring electrode inserted in the space between the substrate and the target, graphite. This system may take an advantage of ${\mu}m$-sized droplets from the sheath electric field near the substrate. As a result, in Ar plasmas, carbon ion motions were suppressed by a strong electric field and were captured in Ar plasmas. Therefore, a low number density of carbon ions were deposited upon substrate. In addition, the plume motions in Ar gas atmosphere was also discussed.

• Journal of Microbiology
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• v.41 no.4
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• pp.295-299
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• 2003

Adenovirus (Ad) precursor to the terminal protein (pTP) plays an essential roles in the viral DNA replication. Ad pTP serves as a primer for the synthesis of a new DNA strand during the initiation step of replication. In addition, Ad pTP forms organized spherical replication foci on the nuclear matrix (NM) and anchors the viral genome to the NM. Here we identified the interferon inducible gene product 1-8D (Inid) as a pTP binding protein by using a two-hybrid screen of a HeLa cDNA library. Of the clones obtained in this assay, nine were identical to the Inid, a 13-kDa polypeptide that shares homology with genes 1-8U and Leu-13/9-27, most of which have little known functions. The entire open reading frame (ORF) of Inid was cloned into the tetracycline inducible expression vector in order to determine the biological functions related with adenoviral infection. When Inid was introduced to the cells along with adenoviruses, fifty to sixty percent of Ad-infected cells expressing Inid had rounded morphology, which was suggestive of apoptosis. Results from the terminal deoxynucleotidyl transferase (TdT) and DNA fragmentation assays confirmed that Inid induces apoptosis in Ad-infected or in uninfected cells. The Inid binding to pTP may target the cell for apoptotic destruction as a host defense mechanism against the viral infection.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.6_spc
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• pp.687-696
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• 2016

A series of process to design an acoustic lens for underwater imaging is reviewed and the method to evaluate characteristics of the lens is investigated. If the target specification of lens is given, the design process consists of the material selection, evaluation of its properties, lens geometry design, prediction of lens characteristics, manufacturing, and evaluation by measurement. In this study, an actual acoustical lens is made by cutting polymethylpentene block. The characteristics of lens are predicted by the hybrid method, combination of ray tracing and Rayleigh integral. For the direct comparison between the prediction and measurement results, a simulation method based on the equivalent source method is suggested to reflect the actual radiation pattern of transducer used for measurements. Finally, the measurement is conducted in a small water tank to observe the actual characteristics of the manufactured lens.

• Laser Solutions
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• v.14 no.4
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• pp.14-20
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• 2011

The advantage of using lasers for through silicon via (TSV) drilling is that they allow higher flexibility during manufacturing because vacuums, lithography, and masks are not required; furthermore, the lasers can be applied to metal and dielectric layers other than silicon. However, conventional nanosecond lasers have disadvantages including that they can cause heat affection around the target area. In contrast, the use of a picosecond laser enables the precise generation of TSVs with a smaller heat affected zone. In this study, a comparison of the thermal and crystallographic defect around laser-drilled holes when using a picosecond laser beam with varing a fluence and repetition rate was conducted. Notably, the higher fluence and repetition rate picosecond laser process increased the experimentally recast layer, surface debris, and dislocation around the hole better than the high fluence and repetition rate. These findings suggest that even the picosecond laser has a heat accumulation effect under high fluence and short pulse interval conditions. To eliminate these defects under the high speed process, the CDE (chemical downstream etching) process was employed and it can prove the possibility to applicate to the TSV industry.

• Child Health Nursing Research
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• v.25 no.3
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• pp.290-302
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• 2019

Purpose: This study aimed to identify the attributes of social adjustment among adolescent cancer survivors using concept analysis and to propose a definition of the concept. Methods: In accordance with the hybrid model of concept analysis, this study employed a three-phase circular process comprising theoretical, fieldwork, and final analysis phases. A thorough literature review was conducted using MEDLINE, Embase, and Korean databases, followed by qualitative fieldwork with seven participants. The results derived from the theoretical and fieldwork phases were integrated into the final analysis phase. Results: Four attributes of social adjustment were found in adolescent cancer survivors: having harmonious relationships with friends, having harmonious relationships with boy/girlfriends, fulfilling their present roles, and planning for and expecting future roles. The following definition of social adjustment of adolescent cancer survivors is proposed: "the conquering of difficulties arising from the continuum of childhood cancer and the achievement of the developmental tasks of typical adolescents." Conclusion: Social adjustment of childhood cancer survivors is crucial for integrating them into society. The findings of this study provide a basis for developing an instrument to measure the social adjustment of adolescent cancer survivors and for developing of interventions that target this group.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.4
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• pp.55-65
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• 2021

The purpose of this paper is to present the Over-The-Top (OTT) platforms' strategies for two-sided markets. For this, we examine six strategic factors influencing OTT's success in Korea. The analysis reveals, among six OTTs, Netflix utilizes five strategic factors except the same-side network effects. OTTs from pay TV operators and channel providers tend to block the cross-side network effects on the opponent OTTs, because they think their giveaway to content providers is in vein, if the invested content by them would be consumed on opponent rival platforms. Interesting is that after experiencing a negative association between the market entry of Netflix and the subscription revenue growth rate of pay TV services, pay TV operators utilize the same-side network effects by offering hybrid services in partnership with global OTTs like Netflix, Disney+ which are considered as a complementary OTT. In conclusion, it is suggested to target a new connected TV based OTT service offering with collaboration with Korean TV device manufacturers for Korean OTTs' global strategy, because Netflix-like global market expansion is not easy for them to cover their content cost.

• Tribology and Lubricants
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• v.38 no.6
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• pp.247-254
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• 2022

Chemical mechanical polishing (CMP) is a hybrid surface-polishing process that utilizes both mechanical and chemical energy. However, the recently emerging semiconductor substrate and thin film materials are challenging to process using the existing CMP. Therefore, previous researchers have conducted studies to increase the material removal rate (MRR) of CMP. Most materials studied to improve MRR have high hardness and chemical stability. Methods for enhancing the material removal efficiency of CMP include additional provision of electric, thermal, light, mechanical, and chemical energies. This study aims to introduce research trends on CMP using ultraviolet (UV) light to these methods to improve the material removal efficiency of CMP. This method, photocatalysis-assisted chemical mechanical polishing (PCMP), utilizes photocatalytic oxidation using UV light. In this study, the target materials of the PCMP application include SiC, GaN, GaAs, and Ru. This study explains the photocatalytic reaction, which is the basic principle of PCMP, and reviews studies on PCMP according to materials. Additionally, the researchers classified the PCMP system used in existing studies and presented the course for further investigation of PCMP. This study aims to aid in understanding PCMP and set the direction of future research. Lastly, since there have not been many studies on the tribology characteristics in PCMP, research on this is expected to be required.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.25 no.4
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• pp.67-89
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• 2022

This study aimed to elucidate the distribution of vascular plants on the Deok mountain in Ganghwa-gun, Korea. The results of 10 field surveys from March to October of 2019 identified 532 taxa in total, representing 482 species, 9 subspecies, 39 varieties, 1 form, and 1 hybrid in 318 genera and 105 families. The plant formation of Deok mountain is the deciduous broad-leaved and conifer mixed forest, which is the common one in the middle region of the Korean Peninsula. Among them, 301 taxa were newly recorded in this study, 7 taxa were endemic plants to Korea, 3 taxa were red list plants. The floristic target plants amounted to 41 taxa, specifically 1 taxon of grade V, 2 taxa of grade IV, 7 taxa of grade III, 9 taxa of grade II, and 22 taxa of grade I. Alien plants were recorded a total of 73 taxa with a naturalized index of 13.7%, the urbanization index was calculated to be 11.8% and 4 taxa were ecosystem disturbance plants.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.1
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• pp.38-46
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• 2023

Carbon neutrality policies have been strengthened to reduce emissions, and the importance of technology road maps has been emphasized. In the global industrial boiler market, carbon neutrality is implemented through fuel diversification of methane-hydrogen mixture gas. However, various problems such as flashback and flame unstability arise. There is a limit to implementing the actual system as it remains in the early stage. Therefore, it is necessary to secure the source technology of methane-hydrogen hybrid combustion system applicable to industrial fields. In this study, control program for methane-hydrogen fuel conversion was developed to expect various parameters. After determining the hydrogen mixing ratio and the input air flow, the fuel conversion control algorithm was constructed to get the parameters that achieve the target oxygen concentration in the exhaust gas. LabVIEW program was used to derive correlations among hydrogen mixing rate, oxygen concentration in exhaust gas, input amount of air and heating value.