• Title/Summary/Keyword: higher order elements

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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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A Study on Metadata Schema Development for the Use, Management and Preservation of Industrial Heritage Resources (산업유산자원의 이용·관리·보존을 위한 메타데이터 요소 설계에 관한 연구)

  • Baek, Jae-Eun
    • Journal of the Korean Society for Library and Information Science
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    • v.56 no.2
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    • pp.231-254
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    • 2022
  • Industrial heritage resources produced by industrial activities have historical and conservative values and value as cultural properties as they serve as a medium connecting the past, present, and future. In other words, Industrial heritage resources should be used, managed, and preserved simultaneously as important records and evidence for the future. Metadata is well known as a necessary and important factor for the use, management, and preservation of information resources. In particular, in order to describe various industrial heritage resources that have historical, cultural, and conservative values, metadata elements from various perspectives are needed to relate to the story, type etc. of data. Therefore, this study attempted to design metadata elements that can comprehensively describe different types of industrial heritage resources. And we designed metadata that suited for the purpose of using, managing, and preserving industrial heritage resources, through mapping and combination between industrial heritage-related metadata. As a result, metadata was grouped into five types(administrative, descriptive, preservation, technical, use) and prepared into a total of 25 higher & 86 lower elements.

A Study on the Self-identity and Satisfaction through Avatar Expression Process (아바타 표현과정 속 자기동일시와 만족도에 관한 연구)

  • Yeu, Ye Kang;Shin, Choon Sung
    • Smart Media Journal
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    • v.11 no.6
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    • pp.18-29
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    • 2022
  • This study proposes an evaluation item model for the avatar expression process, satisfaction and self-identification for each expression element in order to investigate the expression attributes on the influence on the user in setting the avatar. The evaluation of avatar expression method was composed of self-identification and satisfaction by ease of expression and expression elements on the avatar production and expression process. To evaluate the proposed evaluation model, 17 people participated in the experiment. As a result, it was found that most of the participants had a high level of understanding of the production process, and the more diverse the expression elements, the higher the satisfaction with the avatar expression process. Hair shape and face shape were the most important expression factors, and clothes and overall harmony was the most concerned facotrs. Most of them tried to express themselves as realistically as possible. However, in self-identification, there was no significant correlation between expression and production process. In this study identify the decision-making factors that appear in the avatar expression process, the direction in which satisfaction can be formed, and the factors that affect self-identification. In addition, it will be a basic study on how avatars have a lasting influence on users in the future.

Improvement Plans of the Entrepreneurial Ecosystem Using Importance-Performance Analysis (IPA 분석을 통한 창업생태계 개선방안 도출)

  • Kim, Su-Jin;Seo, Kyongran;Nam, Jung-Min
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.17 no.4
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    • pp.101-114
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    • 2022
  • Recently, various studies on the entrepreneurial ecosystem have been conducted. The entrepreneurial ecosystem is composed of various elements such as entrepreneurs, governments, and infrastructure, and these factors interact to contribute to economic development. The purpose of this study was to analyze differences in importance and performance of the entrepreneurial ecosystem for startups using the importance-performance analysis (IPA) method. Based on this, the importance and current level of the components of the entrepreneurial ecosystem were identified and policy implications were presented. The results of the study are as follows. The importance ranking was in the order of startup support program(4.43), startup funding (4.39), market accessibility(4.30). The ranking of performance was startup support program(3.81), ease of starting a business(3.76), support for startup support institutions(3.66), and startup funding(3.66). All elements of the entrepreneurial ecosystem showed higher importance than performance. This means that the components of the entrepreneurial ecosystem in Korea are recognized as important, but do not play a significant role in terms of performance for startups. In addition, the factors with the highest improvement in the importance-performance matrix were 「safety nets for startup failure」, 「culture of acceptance of failure」, 「ease of market entry」, 「ease of startup survival」, and 「ease of exit」. This study suggested improvement measures such as establishing a social safety net, improving awareness of startup failure culture, matching successful startups, strengthening scale-up support by growth stage, easing regulations in new business fields, and diversifying investment recovery strategies.

Fall Risk Assessment of the Elderly living in Nursing Home (노인요양시설 거주 노인의 낙상 위험요인 조사 연구)

  • Yang, Sun-Hee;Park, Young-Hae;Cho, Hae-Sook;Baek, Hee-Chong
    • Journal of Home Health Care Nursing
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    • v.12 no.2
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    • pp.1-15
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    • 2005
  • Purpose: This study was conducted to assess the fall risk factors. Method: The subjects were 87 persons who were older than 65 years living at 28 nursing home in Seoul and Gyunggi province. Subjects were interviewed using RAFS II for intrinsic factor and the environmental factor were assessed using a structured questionnaire from Oct. to Dec. in 2004. The data were analyzed by SPSS(ver. 12.0) programs, using descriptive statistics, $x^2$-test, and t-test. Result: The 37.9% of the subjects experienced the fall, and its average number is $1.94\pm1.75$. The Women's experience of the fall was higher than that of the men, but it was no significant difference with gender. There was no significant difference with the age and duration of living. The mean of the intrinsic risk factor was 13.38 in total score 39 points marks on the RAFS II scales. The intrinsic risk factor score of the fallen group 15.71 was significantly higher than the non-fallen group 12.10. The variables of recent fall experience(t=4.72, p=0.000) and urinary dysfunction(t=2.64, p=0.010) was significantly higher than the non-fallen group. The highest variable of the intrinsic factor was the age and the variables of drug intake, balance, chronic disease, recent fall experience, urinary dysfunction were followed in order. The mean of the environmental risk factor was 0.24 points. No significant differences were shown in environmental risk factor between the fallen and the non-fallen groups. To the fallen group, the place of entrance was the highest risky environmental factor. To see in area dimension, the floor surfaces was the highest risky environmental factor and equipment and illumination factor was the following risky elements in order. In the total score of environmental risk factors based on the ares, the fallen group was 0.26 and the non-fallen group was 0.24, but there were no significant differences between the groups. Conclusion: This results suggested that visual protection strategy, set up the safety device in the place of entrance and inner stairway, bathroom and nonskid mat in the nursing home would be contribute to the prevention of the fall for the elderly.

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A Study on the Electrode Characteristics of a New High Capacity Non-Stoichiometry Zr-Based Laves Phase Alloys for Anode Materials of Ni/MH Secondary Battery

  • Lee Sang-Min;Yu Ji-Sang;Lee Ho;Lee Jai-Young
    • Journal of the Korean Electrochemical Society
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    • v.3 no.2
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    • pp.72-75
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    • 2000
  • For the purpose of developing the non-stoichiometric Zr-based Laves phase alloy with higher capacity and better performance for electrochemical application, extensive work has been carried out in KAIST. After careful alloy design of $ZrMn_2-based$ hydrogen storage alloys through varing their stoichiometry while susbstituting or adding some alloying elements, the $Zr-Ti-(Lh-V-Ni)_{2.2},\;Zr-Ti-(Mn-V-Cr-Ni)_{1.8\pm0.1}$ with high capacity and better performance was developed. Consequently the $Zr-Ti-(Mn-V-Ni)_{2.2}$ alloy has a high discharge capacity of 394mAh/g and shows a high rate capability equaling to that of commercialized $AB_5$ type alloys. On the other hand, in order to develop the hydrogen storage alloy with higher discharge capacity, the hypo-stoichiometric $Zr(Mn-V-Ni)_{2-\alpha}$ alloys substituted by Ti are under developing. As the result of competitive roles of Ti and $stocihiometry({\alpha})$, the discharge capacity of $Zr-Ti-(Mn-V-Cr-Ni)_{l.8\pm0.1}$ alloys is about 400mAh/g(410 mAh/g, which shows the highest level of performance in the Zr-based alloy developed. Our sequential endeavor is improving the shortcoming of Zr-based Laves phase alloy for commercialization, i.e., poor activation property and low rate capability, etc. It is therefore believed that the commercialization of Zr-based Laves phase hydrogen storage alloy for Ni-MH rechargeable battery is in near future.

Numerical Study on the Impact of Regional Warming on the Meterological Field and Ozone Concentration over the South-Eastern Part of the Korean Peninsula (기후변화에 따른 기온상승이 한반도 동남지역 국지 기상장과 오존 분포에 미치는 영향에 관한 수치모의)

  • Jeong, Yeo-Min;Lee, Hwa-Woon;Lee, Soon-Hwan;Choi, Hyun-Jung;Jeon, Won-Bae
    • Journal of Environmental Science International
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    • v.19 no.12
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    • pp.1431-1445
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    • 2010
  • In order to clarify the impact of regional warming on the meteorological field and air quality over southeastern part of Korean Peninsula, several numerical experiment were carried out. Numerical models used in this study are WRF for the estimate the meteorological elements and CMAQ for assessment of ozone concentration. According to the global warming impact, initial air temperature were changed and its warming rate reach at 2 degree which was based on the global warming scenarios provided by IPCC. The experiments considering the global warming at initial stage were presented as case T_UP. Air temperature over inland area during night time for case T_UP is higher than that for Base case. During time since the higher temperature over inland area is maintained during daytime more intensified sea breeze should be induced and also decrease the air temperature in vicinity of coast area. In case of T_UP, high level concentrations ozone distribution area was narrowed and their disappearance were faster after 1800LST. As a results, wind and temperature fields due to the global warming at initial stage mainly results in the pattern of ozone concentration and its temporal variation at South-Eastern Part of the Korean Peninsula.

Improving Watching HDTV Environment by Analyzing Visual Perception of Character Graphics (문자그래픽 시각인지도 분석에 따른 HDTV시청환경 개선 연구)

  • Lee, Kook-Se;Moon, Nam-Mee
    • 한국HCI학회:학술대회논문집
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    • 2009.02a
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    • pp.583-589
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    • 2009
  • The new HDTV technologies provide crystal clear images and surrounding sounds for broadcasting screen in order to serve higher quality of broadcasting. They have four times the resolution of conventional TV and handle 16:9 wide screen aspect ratio images. Due to such technological shift, the function of Character Graphic has been particularly revaluated: it used to be only a subsidiary method to literally deliver visual images, but nowadays it is considered one of the essential elements capable of giving higher values to broadcasting programs. And there is an urgent need for changing its attributes such as fonts, sizes, colors, moving speeds to fit to bigger screen ratio and much more qualified images of HDTV. To meet such a need, Delphi surveys are made twice with three groups of TV production staffs: Art Directors, CG Designers and Production & Transmission team, these groups which are divided on the basis of their roles in broadcasting production process. With the results of these surveys, this article analyzes how all of the attributes of Character Graphic have affected the media users' Visual Perception, and then, suggests a new format designed in OSMU(One Source Multi Use) by which TV character graphics can be properly transmitted to various media formats.

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A Study on the Effect of Mobile Shopping Application Characteristics on Customer Preference : Focusing on Price Sensitivity (쇼핑 애플리케이션의 특성이 애플리케이션의 선호도에 미치는 영향에 관한 연구 가격민감도를 조절효과로-)

  • Kwak, Dong-Sung;Yim, Ki-Heung;Kwon, Jin-Hee
    • Journal of Digital Convergence
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    • v.12 no.6
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    • pp.171-180
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    • 2014
  • Recently, in order to promote their marketing strategy, the entrepeneurs attach importance to many shopping Application services and execute it. The representative elements of shopping Application are interactivity, information offering, convenience of use. This study verified the effects of interactivity, information supplying, and usage convenience, the application characteristics, on the application preferences and repurchase intentions, and the moderating effects of price sensitivity and usage frequency. The result states that the shopping application characteristics affect the shopping application preference, In terms of price sensitivity, the group with higher price sensitivity showed more significant result on the interactivity and usage convenience, and when the information supplying affects on the application preference, the group with higher price sensitivity showed more significant result than the group with lower price sensitivity.

DHC Characteristics of M11 Pressure Tube in Wolsong Unit 1

  • Kim, Sung-Soo;Kim, Young-Suk
    • Nuclear Engineering and Technology
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    • v.32 no.1
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    • pp.1-9
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    • 2000
  • Delayed hydride cracking (DHC) velocity and threshold stress intensity factor for DHC ($K_{IH}$) tests in the radial direction on M11 pressure tube material in Wolsong unit 1 were carried out following the Atomic Energy Canada Limited (AECL) standard test procedure in order to identify the effect of undercooling on DHCV and to acquire the $K_{IH}$ data. The results showed that $K_{IH}$ 's were 8.8$\pm$0.8 MPa√m in the back offcut and 11.4$\pm$0.7 MPa√m in the front offcut. The fact that $K_{IH}$ in the front offcut is about 20% higher than that in the back offcut is attributed to the microstructural difference between the materials of the front and back ends. $K_{IH}$ 's in M11 pressure tube appeared to be higher than the values from the tubes made of double melted ingot reported earlier. This can be interpreted by the fact that very small amounts of Chlorine (Cl) and Phosphorus (P) are contained in the ingot and that the content of the harmful elements in the M11 pressure tube is equivalent to that made of a quadruple melting process. DHC velocities at 25$0^{\circ}C$ in the front offcut in the radial direction are measured to be 5~8$\times$10$^{-8}$ m/s. The results show that the prior thermal history change the DHC velocity significantly. This effect was confirmed by the experiment of undercooling prior to the DHC tests.DHC tests.

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