• Title/Summary/Keyword: Three-generation

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Evaluations of Si based ternary anode materials by using RF/DC magnetron sputtering for lithium ion batteries

  • Hwang, Chang-Muk;Park, Jong-Wan
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.08a
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    • pp.302-303
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    • 2010
  • Generally, the high energy lithium ion batteries depend intimately on the high capacity of electrode materials. For anode materials, the capacity of commercial graphite is unlike to increase much further due to its lower theoretical capacity of 372 mAhg-1. To improve upon graphite-based negative electrode materials for Li-ion rechargeable batteries, alternative anode materials with higher capacity are needed. Therefore, some metal anodes with high theoretic capacity, such as Si, Sn, Ge, Al, and Sb have been studied extensively. This work focuses on ternary Si-M1-M2 composite system, where M1 is Ge that alloys with Li, which has good cyclability and high specific capacity and M2 is Mo that does not alloy with Li. The Si shows the highest gravimetric capacity (up to 4000mAhg-1 for Li21Si5). Although Si is the most promising of the next generation anodes, it undergoes a large volume change during lithium insertion and extraction. It results in pulverization of the Si and loss of electrical contact between the Si and the current collector during the lithiation and delithiation. Thus, its capacity fades rapidly during cycling. Si thin film is more resistant to fracture than bulk Si because the film is firmly attached to the substrate. Thus, Si film could achieve good cycleability as well as high capacity. To improve the cycle performance of Si, Suzuki et al. prepared two components active (Si)-active(Sn, like Ge) elements film by vacuum deposition, where Sn particles dispersed homogeneously in the Si matrix. This film showed excellent rate capability than pure Si thin film. In this work, second element, Ge shows also high capacity (about 2500mAhg-1 for Li21Ge5) and has good cyclability although it undergoes a large volume change likewise Si. But only Ge does not use the anode due to its costs. Therefore, the electrode should be consisted of moderately Ge contents. Third element, Mo is an element that does not alloys with Li such as Co, Cr, Fe, Mn, Ni, V, Zr. In our previous research work, we have fabricated Si-Mo (active-inactive elements) composite negative electrodes by using RF/DC magnetron sputtering method. The electrodes showed excellent cycle characteristics. The Mo-silicide (inert matrix) dispersed homogeneously in the Si matrix and prevents the active material from aggregating. However, the thicker film than $3\;{\mu}m$ with high Mo contents showed poor cycling performance, which was attributed to the internal stress related to thickness. In order to deal with the large volume expansion of Si anode, great efforts were paid on material design. One of the effective ways is to find suitably three-elements (Si-Ge-Mo) contents. In this study, the Si based composites of 45~65 Si at.% and 23~43 Ge at.%, and 12~32 Mo at.% are evaluated the electrochemical characteristics and cycle performances as an anode. Results from six different compositions of Si-Ge-Mo are presented compared to only the Si and Ge negative electrodes.

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Effects of 1-Methylcyclopropene and Benzyladenine on Flowering and Vase Life in Cut Iris (아이리스 개화율 및 절화수명에 미치는 1-methylcyclopropene과 benzyladenine의 영향)

  • Nam, Jin Soo;Park, In Sook;Shim, Sung Im;Ryu, Jung A;Lim, Ki Byung
    • FLOWER RESEARCH JOURNAL
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    • v.18 no.2
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    • pp.87-92
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    • 2010
  • This research was aimed to extend the vase life, improve the cut flower quality and promote flowering rate of bulbous cut Iris 'Blue Magic'. Three different concentrations of 1-MCP ranging from 250 to $750nL{\cdot}L^{-1}$ were treated on cut Iris flowers for the vase life elongation. Several effects of 1-MCP treatment has shown such as early flowering as one day but vase life showed no significant differences comparing to the untreated control. Flowering rate was 75% or more in the treated ones as compare to 64.2% in untreated control. Especially, in a treatment with $250nL{\cdot}L^{-1}$ 1-MCP for 12 hours it showed all flowering. In many post-harvest experiments of cut flowers, ethylene production from flower organ has considered as most critical factor on vase life. Ethylene production from flower organ was measured by gas chromatography (GC) and it showed that there is no direct relation between flower longevity and emission of the ethylene gas in cut Iris. In comparison with the untreated control, ethylene generation rather seems to be increased as 1-MCP treatment increased. There was a synergy effect when 1-MCP and BA applied simultaneously in which flowering and vase life were fastened and also extended, respectively. Therefore, treatment of 1-MCP for cut Iris at flower early harvest is able to improve the flower quality both by diminishing non-flowering rate and by extended flower longevity.

Application of Multispectral Remotely Sensed Imagery for the Characterization of Complex Coastal Wetland Ecosystems of southern India: A Special Emphasis on Comparing Soft and Hard Classification Methods

  • Shanmugam, Palanisamy;Ahn, Yu-Hwan;Sanjeevi , Shanmugam
    • Korean Journal of Remote Sensing
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    • v.21 no.3
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    • pp.189-211
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    • 2005
  • This paper makes an effort to compare the recently evolved soft classification method based on Linear Spectral Mixture Modeling (LSMM) with the traditional hard classification methods based on Iterative Self-Organizing Data Analysis (ISODATA) and Maximum Likelihood Classification (MLC) algorithms in order to achieve appropriate results for mapping, monitoring and preserving valuable coastal wetland ecosystems of southern India using Indian Remote Sensing Satellite (IRS) 1C/1D LISS-III and Landsat-5 Thematic Mapper image data. ISODATA and MLC methods were attempted on these satellite image data to produce maps of 5, 10, 15 and 20 wetland classes for each of three contrast coastal wetland sites, Pitchavaram, Vedaranniyam and Rameswaram. The accuracy of the derived classes was assessed with the simplest descriptive statistic technique called overall accuracy and a discrete multivariate technique called KAPPA accuracy. ISODATA classification resulted in maps with poor accuracy compared to MLC classification that produced maps with improved accuracy. However, there was a systematic decrease in overall accuracy and KAPPA accuracy, when more number of classes was derived from IRS-1C/1D and Landsat-5 TM imagery by ISODATA and MLC. There were two principal factors for the decreased classification accuracy, namely spectral overlapping/confusion and inadequate spatial resolution of the sensors. Compared to the former, the limited instantaneous field of view (IFOV) of these sensors caused occurrence of number of mixture pixels (mixels) in the image and its effect on the classification process was a major problem to deriving accurate wetland cover types, in spite of the increasing spatial resolution of new generation Earth Observation Sensors (EOS). In order to improve the classification accuracy, a soft classification method based on Linear Spectral Mixture Modeling (LSMM) was described to calculate the spectral mixture and classify IRS-1C/1D LISS-III and Landsat-5 TM Imagery. This method considered number of reflectance end-members that form the scene spectra, followed by the determination of their nature and finally the decomposition of the spectra into their endmembers. To evaluate the LSMM areal estimates, resulted fractional end-members were compared with normalized difference vegetation index (NDVI), ground truth data, as well as those estimates derived from the traditional hard classifier (MLC). The findings revealed that NDVI values and vegetation fractions were positively correlated ($r^2$= 0.96, 0.95 and 0.92 for Rameswaram, Vedaranniyam and Pitchavaram respectively) and NDVI and soil fraction values were negatively correlated ($r^2$ =0.53, 0.39 and 0.13), indicating the reliability of the sub-pixel classification. Comparing with ground truth data, the precision of LSMM for deriving moisture fraction was 92% and 96% for soil fraction. The LSMM in general would seem well suited to locating small wetland habitats which occurred as sub-pixel inclusions, and to representing continuous gradations between different habitat types.

A Fast Digital Elevation Model Extraction Algorithm Using Gradient Correlation (Gradient Correlation을 이용한 고속 수치지형표고 모델 추출 방법)

  • Chul Soo Ye;Byung Min Jeon;Kwae Hi Lee
    • Korean Journal of Remote Sensing
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    • v.14 no.3
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    • pp.250-261
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    • 1998
  • The purpose of this paper is to extract fast DEM (Digital Elevation Model) using satellite images. DEM extraction consists of three parts. First part is the modeling of satellite position and attitude, second part is the matching of two images to find corresponding points of them and third part is to calculate the elevation of each point by using the results of the first and second part. The position and attitude modeling of satellite is processed by using GCPs. A area based matching method is used to find corresponding points between the stereo satellite images. The elevation of each point is calculated using the exterior orientation parameters obtained from modeling and conjugate points from matching. In the DEM generation system, matching procedure holds most of a processing time, therefore to reduce the time for matching, a new fast matching algorithm using gradient correlation and fast similarity measure calculation method is proposed. In this paper, the SPOT satellite images, level 1A 6000$\times$6000 panchromatic images are used to extract DEM. The experiment result shows the possibility of fast DEM extraction with the satellite images.

In vitro correlation between anti-inflammatory and anti-oxidant effects of stone and seed of peaches cultivars (복숭아 품종별 핵과 종자의 항염증 및 항산화 효과간의 상관관계)

  • Jung, Kyung-Mi;Bae, Seung-hwa
    • Food Science and Preservation
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    • v.25 no.1
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    • pp.90-97
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    • 2018
  • Peach seeds contain a large amount of phenolic components and exhibit excellent physiological effects in various diseases. We examined the antioxidant effects of stone and seed of three peach cultivars (Miwhang, MH; Kanoiwa hakuto, KH; and Cheonhong, CH) by 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, ferric reducing activity of plasma (FRAP) assay, and cupric ion reducing antioxidant capacity (CUPRAC) reduction. The results showed that the stone extracts of CH had higher levels of total phenols and flavonoids than those of the other cultivars do, and the stone extracts of KH and CH have the potential to reduce DPPH, FRAP, and CUPRAC activities. In addition, we found that KH, MH, and CH stone extracts decreased nitric oxide generation in RAW 264.7 and BV2 cells. The total phenol and flavonoid contents had no significant correlation with anti-oxidant activities. On the other hand, the anti-inflammatory activity had a low linear correlation with anti-oxidant activities and total phenol and flavonoid contents. The present results suggest that the correlation between antioxidant and anti-inflammatory effects of stone and seed, and the appropriate combination of the stone and seed extracts could be used as an anti-inflammatory treatment and prevention material, respectively.

Perception of Japanese word-initial stops by native listeners (모어청자에 의한 일본어 어두 폐쇄음의 지각)

  • Byun, Hi-Gyung
    • Phonetics and Speech Sciences
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    • v.13 no.3
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    • pp.53-64
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    • 2021
  • It is known that the voicing contrast for Japanese word-initial stops is primarily realized as differences in the voice onset time (VOT). However, recent studies have reported that voiced stops are more often produced with a positive VOT than with a negative VOT among the younger generation nationwide. It is also known that post-stop F0 is associated with the stop contrast, but the degree of F0 use differs from region to region. This study explores whether the difference in post-stop F0 functions as a perceptual cue to the stop contrast along with VOT. Fifty-five college students who are native listeners from four different regions participated in two or three perception tests. The results show that VOT is a primary cue to the voiced-voiceless distinction of word-initial stops, but that the effect of post-stop F0 on the stop contrast is marginal. The post-stop F0 is involved in perception only when VOT is ambiguous, such that a sound with high F0 is more often perceived as a voiceless stop, but not vice versa. The results of this study indicate that the acoustic parameters associated with the stop contrast are not the same in production and perception, and suggest that other factors such as context, which is not an acoustic characteristic, may also be involved in the stop contrast.

The Impact of Organizational Safety Culture on the Resilience Ability : Focused on the Construction Industry (조직의 안전문화가 레질리언스 역량에 미치는 영향 : 건설업을 중심으로)

  • Chu, Chan Ho;An, Kang Min;Baek, Dong Hyun
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.44 no.3
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    • pp.73-85
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    • 2021
  • The construction industry is considered to be a fatal accident industry, accounting for 28.5% of the total industrial accidents in 2017, as the number of industrial accidents in the construction industry has steadily increased over the past decade. So it is necessary to consider introducing Resilience Engineering, which is actively applied to risky industries around the world, to drastically reduce construction accidents. Although Resilience Engineering, which has emerged as the next-generation safety management centered on Hollnagel since the 2000s, claims the importance of strengthening Resilience abilities considering organizational structure and culture, most studies focus only on developing evaluation indicators. The purpose of this study is to analyze the impact of an organization's safety culture on its Resilience abilities in the construction industry. Specifically, it conducted empirical analysis on the impact of safety culture consisting of 'communication, leadership and safety systems' on the Resilience abilities(responding ability, monitoring ability, learning ability, anticipating ability), and the mediation relationship between leadership, communication, and safety system. The survey was conducted on construction workers, and an empirical analysis was conducted on the final 154 responses using SPSS 25 and Smart PLS 3. The results showed that the safety system had a significant impact on all Resilience Abilities, and communication had a significant impact on the remaining three except for anticipating ability among Resilience Abilities. On the other hand, leadership has been shown to have a significant impact on anticipating ability only. In the verifying of the mediation relationship between leadership, communication and safety systems, it was found that leadership affects all Resilience abilities by means of safety systems, but communication can only affect responding ability. This study has practical significance in that it suggests the need for policy-level efforts to introduce and apply Resilience Engineering and then expanded the effective safety management assessment of the construction industry in the future. Moreover, the academic implications are important in that the study attempted to expand the academic scope for a paradigm shift in the future as the safety culture has identified its impact on the Resilience abilities.

Analysis of Soil Fungal Community Related to Rhododendron mucronulatum in Biseul Mountain County Park, South Korea (우리나라 비슬산군립공원 진달래나무(Rhododendron mucronulatum)와 관련된 토양 진균 군집의 pyrosequencing 분석)

  • Jeong, Min-Ji;Kim, Dong-Hyun;Choi, Doo-Ho;Lee, In-Seon;Kim, Jong-Guk
    • Journal of Life Science
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    • v.31 no.4
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    • pp.377-384
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    • 2021
  • Researching the soil fungal community is important to understand the interaction between fungi and living plants. However, too few studies have examined the soil fungal community and their interactions with plants. Rhododendron mucronulatum, commonly known as Korean rosebay, is an important forest resource that has aesthetic, ecological, and potential pharmacological values. We used a pyrosequencing method to analyze the characteristics of fungal communities from R. mucronulatum soil samples from Biseul mountain county park, which is one of the famous places for large R. mucronulatum colonies in South Korea. We collected soil core samples in February and August at three sites in the Biseul Mountain County Park, taking into consideration the regional and seasonal conditions. We obtained 454,157 validated reads after pyrosequencing all six samples. The fungal communities from the first observation spot in August had the richest species diversity among the samples. Basidiomycota, Ascomycota, and Mortierellomycota were major phyla in the samples. Agaricales_f, Mortierellaceae, and Clavariaceae were major families in the samples. The genus Mortierella was the most dominant in all six samples. Overall, 19 genera could be associated with R. mucronulatum. Sample 1 had 109 genera in sample 1, sample 2 had 111 genera, and sample 3 had 112 genera that were uniquely identified. The samples collected in August had 28 identified genera, that existed only in summer samples, indicating a weather effect. This study can be used as basic research to understand the relationship between soil fungi and plants.

A Study on Narrative Response to the Lack of Family in the Chinese Contemporary Growth Novel After the 1990s (1990년대 이후 중국 당대 성장소설에 나타난 가족결핍과 그 서사적 대응방식)

  • Kim, Bong-yeon
    • Cross-Cultural Studies
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    • v.47
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    • pp.1-26
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    • 2017
  • This paper focuses on three novels that reflect absence of family. Conflicts caused by absence of parents or lack of function and role of parents were principle drivers fueling growth novels. In Chinese growth novels, children in a long-standing tradition of emulsion and political pressure were unable to express their conflict with parents. Out of the collective interest and only until the late 1980s, which can be found of the individuals were able to fully appreciate the growth of children. Since the late 1990s, the creative individual cases to the growth is an important point of Chinese growth. Due to a close relationship of the literature and politics further noteworthy that the growth of state for personal growth for China's growth. Reform and opening up the end of the Cultural Revolution, the emergence of new generation of cultural sensitivity with a relatively free personal attention to the growth of the chance that can be. In this paper, created since the 1990s, the growth of the stories of yuhua (余華)'s "Cry in the Rain"("在細雨中呼喊"), sutong(蘇童)'s "The Northern Part of the City"("城北地帶"), wanggang(王剛)'s "English"("英格力士"), going to go through by focusing on how to respond in the lack of family. "Cry in the Rain" shows that a consciousness orphan child abandoned main actors 'consciousness from his birth parents and adoptive parents. "The Northern Part of the City" chronicles different growth stories of children who experienced a void because of their absent families and found comfort in peer groups. "English" is distinguished from the mainstream narrative of Chinese growth in terms of creating a role model. Individual growth through the role model in that it will eventually establish their own identities and further growth. Because of that, this novel is considered best practices of Chinese growth novels. This kind of narrative, which returns to the memory of the growth of growth, has a richer connotation amid various attempts by writers out of the past era of obsession and fatigue.

High Voltage β-Ga2O3 Power Metal-Oxide-Semiconductor Field-Effect Transistors (고전압 β-산화갈륨(β-Ga2O3) 전력 MOSFETs)

  • Mun, Jae-Kyoung;Cho, Kyujun;Chang, Woojin;Lee, Hyungseok;Bae, Sungbum;Kim, Jeongjin;Sung, Hokun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.32 no.3
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    • pp.201-206
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    • 2019
  • This report constitutes the first demonstration in Korea of single-crystal lateral gallium oxide ($Ga_2O_3$) as a metal-oxide-semiconductor field-effect-transistor (MOSFET), with a breakdown voltage in excess of 480 V. A Si-doped channel layer was grown on a Fe-doped semi-insulating ${\beta}-Ga_2O_3$ (010) substrate by molecular beam epitaxy. The single-crystal substrate was grown by the edge-defined film-fed growth method and wafered to a size of $10{\times}15mm^2$. Although we fabricated several types of power devices using the same process, we only report the characterization of a finger-type MOSFET with a gate length ($L_g$) of $2{\mu}m$ and a gate-drain spacing ($L_{gd}$) of $5{\mu}m$. The MOSFET showed a favorable drain current modulation according to the gate voltage swing. A complete drain current pinch-off feature was also obtained for $V_{gs}<-6V$, and the three-terminal off-state breakdown voltage was over 482 V in a $L_{gd}=5{\mu}m$ device measured in Fluorinert ambient at $V_{gs}=-10V$. A low drain leakage current of 4.7 nA at the off-state led to a high on/off drain current ratio of approximately $5.3{\times}10^5$. These device characteristics indicate the promising potential of $Ga_2O_3$-based electrical devices for next-generation high-power device applications, such as electrical autonomous vehicles, railroads, photovoltaics, renewable energy, and industry.