• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.369-372
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• 2004

The characteristics of antimony implants are relatively well-known. Antimony has lower diffusion coefficient, shorter implantation range, and smaller scattering as compared with conventional dopants such as phosphorous and arsenic. It has been commonly used in the doping of buried layer in Bi-CMOS process. In this paper, characteristics and appropriate condition of monitoring in antimony implant beam tuning using $Sb_2O_3$ were investigated to get a reliable process. TW(Thema Wave) and Rs(Sheet Resistance) test were carried out to set up condition of monitoring for stable operation through the periodic inspection of instruction condition. The monitoring was progressed at the point that the slant of Rs varied significantly to investigate the variation of instruction accurately.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.227-229
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• 2004

The corrosion rate of buried steel pipes for water works was investigated under soil environment. Steel pipe shows various characteristics caused by complicated environment condition of underground and especially the corrosion rate of it depends on the resistivity of soil controlled by content of water. In this paper, the corrosion behavior of steel pipe was observed by polarization test under soil and the silica sand in the water content range of 0-50%. Generally it is well known that the resistivity of soil decreased rapidly over 15% water content. In fact the corrosion rate, corrosion potential, and corrosion consumption (MPY) of steel pipe were shown very different aspects within 20% water content.

• Journal of Sensor Science and Technology
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• v.17 no.6
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• pp.447-453
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• 2008

Respiration rate is one of the important vital signs. Photo-plethysmography (PPG) measurement especially on a finger has been widely used in pulse oximetry and also used in estimating respiration rate. It is well known that PPG contains respiration-induced intensity variation (RIIV) signal. However, the accuracy of finger PPG method has been controversial. We introduced a new technique of enhancing motion artifact by respiration. This was achieved simply by measuring PPG on the thorax. We examined the accuracy of these two PPG methods by comparing with two existing methods based on thoracic volume and nostril temperature changes. PPG sensing on finger tip, which is the most common site of measurement, produced 6.1 % error. On the other hand, our method of PPG sensing on the thorax achieved 0.4 % error which was a significant improvement. Finger PPG is sensitive to motion artifact and it is difficult to recover fully small respiratory signal buried in waveform dominated by absorption due to blood volume changes. Thorax PPG is poor to represent blood volumes changes since it contains substantial motion artifact due to respiration. Ironically, this inferior quality ensures higher accuracy in terms of respiration measurement. Extreme low-cost and small-sized LED/silicon detector and non-constrained reflection measurement provide a great candidate for respiration estimation in ubiquitous or personal health monitoring.

• Journal of the Korean Geosynthetics Society
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• v.13 no.4
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• pp.153-159
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• 2014

During the winter and spring seasons in Korea, structures such as buried water supply pipelines, roads, railways are frequently damaged due to frost heaving and thawing. Until now, the method of substituting the frost susceptible soil with the gravel or rubbles those are non-frost susceptible materials have been employed in Korea to prevent frost heaving. A series of laboratory soil tests and indoor frozen soil engineering experiments, as well as laboratory frost heaving tests were conducted for seeking the means of utilizing recycled PET bottles as substitute material.

• Applied Microscopy
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• v.50
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• pp.24.1-24.11
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• 2020

The development of the femtosecond laser (fs laser) with its ability to provide extremely rapid athermal ablation of materials has initiated a renaissance in materials science. Sample milling rates for the fs laser are orders of magnitude greater than that of traditional focused ion beam (FIB) sources currently used. In combination with minimal surface post-processing requirements, this technology is proving to be a game changer for materials research. The development of a femtosecond laser attached to a focused ion beam scanning electron microscope (LaserFIB) enables numerous new capabilities, including access to deeply buried structures as well as the production of extremely large trenches, cross sections, pillars and TEM H-bars, all while preserving microstructure and avoiding or reducing FIB polishing. Several high impact applications are now possible due to this technology in the fields of crystallography, electronics, mechanical engineering, battery research and materials sample preparation. This review article summarizes the current opportunities for this new technology focusing on the materials science megatrends of engineering materials, energy materials and electronics.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.3996-4004
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• 2022

The data collected by the In-Situ Decommissioning (ISD) sensors are time-specific, age-specific, and developmental stage-specific. Research has been done on the stream data collected by ISD testbed in the recent few years to seek both frequent episodes and abnormal frequent episodes. Frequent episodes in the data stream have confirmed the daily cycle of the sensor responses and established sequences of different types of sensors, which was verified by the experimental setup of the ISD Sensor Network Test Bed. However, the discovery of abnormal frequent episodes remained a challenge because these abnormal frequent episodes are very small signals and may be buried in the background noise of voltage and current changes. In this work, we proposed Advanced Data Analytics (ADA) methods that are applied to the baseline data to identify frequent episodes and extended our approach by adding more features extracted from the baseline data to discover abnormal frequent episodes, which may lead to the early indicators of ISD system failures. In the study, we have evaluated our approach using the baseline data, and the performance evaluation results show that our approach is able to discover frequent episodes as well as abnormal frequent episodes conveniently.

• Structural Engineering and Mechanics
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• v.82 no.4
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• pp.417-434
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• 2022

In this work, a review of mechanical metamaterials and seismic protection systems that use them is carried out, focusing on passive protection systems. During the last years, a wide variety of classical systems of seismic protection have demonstrated to be an effective and practical way of reducing the seismic vulnerability of buildings, maintaining their health and structural integrity. However, with the emergence of metamaterials, which allow obtaining uncommon mechanical properties, new procedures and devices with high performance have been developed, reducing the seismic risk through novel approaches such as: seismic shields and the redirection of seismic waves; the use of stop band gaps and the construction of buried mass resonators; the design of pentamodal base isolators. These ideas are impacting traditional areas of structural engineering such as the design and building of highly efficient base isolation systems. In this work, recent advances in new seismic protection technologies and researches that integrate mechanical metamaterials are presented. A complete bibliometric analysis was carried out to identify and classify relevant authors and works related with passive seismic protection system based on mechanical metamaterial (pSPSmMMs). Finally, possible future scenarios for study and development of seismic isolators based on mechanical metamaterials are shown, identifying the relevant topics that have not yet been explored, as well as those with the greatest potential for future application.

• The Korean Journal of Mycology
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• v.51 no.4
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• pp.491-504
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• 2023

To explore fungal diversity in orchard soil where fire-blighted apple trees are buried, we collected soil samples from apple orchards in Chungju, Korea. Fungal isolates were obtained from DG18 agar and identified at the species level based on morphological features and phylogenetic analyses. The colony characteristics and microstructures were examined using a light microscope and a scanning electron microscope after culturing on potato dextrose agar (PDA), malt extract agar (MEA), Czapek yeast agar (CYA), and oatmeal agar (OA) The PCR-amplified products of the ITS1-5.8S-ITS2 region and 28S large subunit of the nuclear ribosomal RNA gene, as well as partial sequences of the β-tubulin, calmodulin, and translation elongation factor 1-α genes were sequenced and analyzed phylogenetically. Seven previously unknown fungal species were explored in Korea. All samples, including Aspergillus aureolatus, Botryotrichum atrogriseum, Dactylonectria novozelandica, Fusarium denticulatum, Paecilomyces tabacinus, Sarcopodium tibetense and Talaromyces stollii, had ascomycetes. Herein, we report their descriptions and features.

• Korean Journal of Agricultural Science
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• v.43 no.4
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• pp.560-566
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• 2016

Imports of genetically modified (GM) soybeans (Glycine max) for food or feed consumption in Korea have been increasing. Although the cultivation of GM soybeans has not yet been allowed in Korea, the number of field tests for GM soybeans has also been rising. This study was conducted to investigate whether herbicide tolerant GM soybean can survive and persist in uncultivated environments when they escape from transportation routes or from isolated fields. Seeds of GM and non-GM soybeans and wild soybeans (Glycine soja) were buried in 2 and 15 cm soil depths and their viability was examined after 1, 2, 6, and 10 months. GM and non-GM soybean seeds completely lost their viability within six months of burial, whereas seeds of wild soybean maintained their viability during the study period. Seeds of soybean and wild soybeans that were sown on the soil surface germinated and grew to vegetative cotyledon stage. Seedlings of GM and non-GM soybean did not compete well with weeds, including Cerastium glomeratum, Alopecurus aequalis var. amurensis, Capsella bursa-pastoris, Conyza canadensis, Stellaria aquatica, and Erigeron annuus. Also, GM soybean did not survive through winter. However, wild soybeans competed well with the weeds and became dominant in August. Herbicide tolerant GM soybean is unlikely to persist under uncultivated environments and to become weeds.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.49.1-49.1
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• 2017

Comets are one of the most primordial solar system objects that hold the information of the early days of solar system formation inside their nuclei. Orbiting the Sun, they spew such ancient materials that have been buried for many years, creating dust and gas comae. Cometary dust grains absorb and scatter sunlight radiating the continuous light, while gas molecules form the line emissions. Eachof the comets has its own light patterns, which depends on the physical and chemical properties of the dust and gas components. In this regard, spectropolarimetrycan be a powerful tool to study the properties of cometary constituents free from contamination of each other. This methodology offers a series of information on the polarization degrees of the dust and gas components as well as on wavelength dependence of the polarization degree and polarization angle of cometary dust simultaneously. Herein, we will report the results of the spectropolarimetric study of comet 2P/Encke, which is one of the well-known objects for its shortest orbital period and its prominent aging signals. We performed a spectropolarimetric observation of comet 2P/Encke in its inbound orbit using the Higashi-Hiroshima Optical and Near-Infrared Camera (HONIR) at the Higashi-Hiroshima Observatory, Japan, on UT 2017 February 21 at high phase angle of =75.7 deg. Ourstudy of this interesting comet is the first and only one done through spectropolarimetry in a referred publication. We will discuss the most recent polarimetric results of our study in terms of 2P/Encke' scurrent evolutionary status.