• Title/Summary/Keyword: Group-14 elements

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A STUDY ON THE GALVANIC CORROSION OF TITANIUM USING THE IMMERSION AND ELECTROCHEMICAL METHOD (침적법과 전기화학법을 이용한 티타늄의 갈바닉 부식에 관한 연구)

  • Kay, Kee-Sung;Chung, Chae-Heon;Kang, Dong-Wan;Kim, Byeong-Ok;Hwang, Ho-Gil;Ko, Yeong-Mu
    • The Journal of Korean Academy of Prosthodontics
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    • v.33 no.3
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    • pp.584-609
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    • 1995
  • The purpose of this study was to evaluate the difference of the galvanic corrosion behaviour of the titanium in contact with gold alloy, silva-palladium alloy, and nickel-chromium alloy using the immersion and electrochemical method. And the effects of galvallit couples between titanium and the dental alloys were assessed for their usefulness as materials for superstructure. The immersion method was performed by measuring the amount of metal elementsreleased by Inductivey coupled plasma emission spectroscopy(ICPES) The specimen of fifteen titanium plates, the five gold alloy, five silver-palladium, five nickel-chromium plates, and twenty acrylic resin plates ware fabricated, and also the specimen of sixty titanium plugs, the thirty gold alloy, thirty silver-palladium, and nickelc-hromium plugs were made. Thereafter, each plug of gold alloy, silver-palladium, and nickel-chromium inserted into the the titanium and acrylic resin plate, and also titanium plug inserted into the acrylic resin plate. The combination specimens uf galvanic couples immersed in 70m1 artificial saliva solution, and also specimens of four type alloy(that is, titanium, gold, silver-palladium and nickel-chromium alloy) plugs were immersed solely in 70m1 artificial sativa solution. The amount of metal elements released was observed during 21 weeks in the interval of each seven week. The electrochemical method was performed using computer-controlled potentiosta(Autostat 251. Sycopel Sicentific Ltd., U.K). The wax patterns(diameter 11.0mm, thickness,in 1.5mm) of four dental casting alloys were casted by centrifugal method and embedded in self-curing acrylic resin to be about $1.0cm^2$ of exposed surface area. Embedded specimens were polished with silicone carbide paper to #2,000, and ultrasonically cleaned. The working electrode is the specimen of four dental casting alloys, the reference electrode is a saturated calmel electrode(SCE) and the ounter electrode is made of platinum plate. In the artificial saliva solution, the potential scanning was carried out starting from-700mV(SCE) TO +1,000mV(SCE) and the scan rate was 75mV/min. Each polarization curve of alloy was recorded automatically on a logrithmic graphic paper by XY recorder. From the polarization curves of each galvanic couple, corrosion potential and corrosion rates, that is, corrosion density were compared and order of corrosion tendency was determined. From the experiments, the following results were obtained : 1. In the case of immersing titanium, gold alloy, silver-palladium alloy, and nickel-chromium alloysolely in the artificial saliva solution(group 1, 2, 3, and 4), the total amount of metal elements released was that group 4 was greater about 2, 3 times than group 3, and about 7.8 times than group 2. In the case of group 1, the amount of titanium released was not found after 8 week(p<0.001). 2. In the case of galvanic couples of titanium in contact with alloy(group 5, 6), the total amount of metal elements released of group 5 and 6 was less than that of group 7, 8, 9, and 10(p<0.05). 3. In the case of galvanic couples of titanium in contact with silver-palladium alloy(group 7, 8), the total amount of metal elements released of group 7 was greater about twice than that of group 5, and that of group 8 was about 14 times than that of group 6(p<0.05). 4. In the case of galvanic couples of titanium in contact with nickel-chromium alloy(group 9, 10), the total amount of metal elements released of group 9 and 10 was greater about 1.8-3.2 times than that of group 7 and 8, and was greater about 4.3~25 times than that of group 5 and 6(p<0.05). 5. In the effect of galvanic corrosion according to the difference of the area ratio of cathode and anode, the total amount of metal elements released was that group 5 was greater about 4 times than group 6, group 8 was greater about twice than group 7, and group 10 was greater about 1.5 times than group 9(p<0.05). 6. In the effect of galvanic corrosion according to the elasped time during 21 week in the interval of each 7 week, the amount of metal elements released was decreased markedly in the case of galvanic couples of the titanium in contact with gold alloy and silver-palladium alloy but the total amount of nickel and beryllium released was not decreased markedly in the case of galvanic couples of the titanium in contact with nickel-chromium alloy(p<0.05). 7. In the case of galvanic couples of titanium in contact with gold alloy, galvanic current was lower than any other galvanic couple. 8. In the case of galvanic couples of titanium in contact with nickel-chromium alloy, galvanic current was highest among other galvanic couples.

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Developing Job Description for Dietitians Working in Public Health Nutrition Areas (보건소 영양사를 위한 직무 기술서 개발)

  • Cha, Jin-A;Park, Hae-Ryun;Lim, Young-Suk;Lim, Seung-Hee
    • Korean Journal of Community Nutrition
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    • v.13 no.6
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    • pp.890-902
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    • 2008
  • The purpose of this study was to develop a standardized job description for dietitians working in the public health nutrition area. Work-oriented job analysis methodology was employed for the study purpose. Subjects of 38 dietitians currently working at health centers in 2002 were recruited. Based on the focus group interview with 7 public health nutritionists and 7 professors, information about task elements was collected. Questionnaires measuring work performance and self-perception of importance of the selected task elements were administered. Reliability and validity of this instrument were tested by Chronbach's alpha and factor analysis. SAS PC package program was used for the statistical analysis. The final developed job description for public health nutritionists included 5 duties, 20 tasks and 93 task elements. The results of this study can be summarized as follows; 1) 5 duty areas are A. plan and evaluation of public health nutrition services, B. developing nutrition education materials, C. implementing nutrition services, D. networking community, and E. self development. 2) Each duty area from A to E was composed with 6, 2, 6, 4, 2 tasks, respectively. 3) Each duty area from A to E was composed with 24, 8, 38, 14, 9, and 2 task elements, respectively.

Effect on Milking Performance of Vitamin-Trace Element Supplements to Early Lactation Italian Brown Cows Grazing Ryegrass (Lolium multiflorum) Pasture

  • Tufarelli, Vincenzo;Khan, R.U.;Laudadio, V.
    • Asian-Australasian Journal of Animal Sciences
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    • v.24 no.9
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    • pp.1227-1232
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    • 2011
  • The objective of this study was to examine the effects of concentrates containing different levels of a vitamin-trace elements premix on milk yield and composition of dairy cows. The trial, which lasted 14 weeks, was conducted from January to March and used 45 multiparous Brown cows in the early phase of lactation. Cows (n = 15 per treatment) were randomly allocated to three dietary treatments: the first group (control, C-0) was fed pelleted concentrate containing background vitamins and trace elements that supplied 1.0 times cows' daily requirements; the second group were fed the same concentrate, but containing 2.5 g/kg of vitamin and trace mineral premix per kg of concentrate (C-2.5); the third group were fed the same concentrate, but containing 5 g/kg of vitamin and trace mineral premix per kg of concentrate (C-5). The daily ration included ad libitum chopped oat hay, and the cows also had 8 h/d grazing on a ryegrass (Lolium multiflorum) pasture. During the performance trial, cow milk yield was daily recorded and individual milk samples were analysed for milk composition and to determine milk renneting properties. Cows fed the intermediate premix level (C-2.5) in diet showed the highest fat-corrected milk production (p<0.05) compared to other groups. None of the milk quality parameters studied were influenced by dietary treatment, except for milk rheological parameters (rennet clotting time and curd firmness) that were positively improved in cows fed the C-2.5 diet (p<0.05). The findings from this study show that intermediate level of vitamin-trace elements premix in concentrate can be advantageously used in grazing dairy cows without negative effects on yield and quality of milk produced.

Pre-service Teachers' Perceptions of Successful Science Classes' Components (성공적인 과학 수업 구성 요소에 대한 예비교사들의 인식)

  • Seongun Kim;Sungman Lim
    • Journal of the Korean Society of Earth Science Education
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    • v.16 no.2
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    • pp.276-290
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    • 2023
  • The purpose of this study is to analyze the characteristics and specific elements of successful science classes that pre-service elementary school teachers think. For the study, 61 pre-service elementary school teachers (47 females, 14 males) were recruited as research participants. The data used in the study are mutual evaluation papers prepared during class performances by group and individual. The amount of data was a vast amount of qualitative data with a total of 150 pages, and the research results were derived by inductively categorizing this data through qualitative analysis. The summary of the research results is as follows. First, the factors constituting a successful science class were analyzed into 7 categories (14 sub-categories, 33 sub-elements). The elements that make up a successful science class in detail were analyzed as science subject contents, class management, selection of teaching and learning methods and organization of class contents, teaching and learning materials, understanding of students, understanding of teaching situations, and class-related efforts. Second, it was possible to describe the practical classes of pre-service teachers by collecting the details of the elements that make up a successful science class recognized by pre-service teachers. As seen in the above research results, the characteristics and specific elements of successful science classes recognized by pre-service teachers were identified, and based on this, pre-service teachers will be able to develop support for effective science class operation, and continuous analysis should be conducted.

The Study about the Emotional Status of Patients Who want to take Medical Examination on Stroke (중풍(中風)에 대한 健康檢診(건강검진)을 받고자 내원(來院)한 환자(患者)의 정서상태(情緖狀態)에 대한 연구(硏究))

  • Park Se-Jin;Park Sang-Dong;Lee Jeong-A
    • Journal of Oriental Neuropsychiatry
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    • v.12 no.2
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    • pp.123-133
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    • 2001
  • This study was designed and undertaken to identify objectively the degree and relationship of anxiety, depression which are chief essential elements of emotional status in Stroke medical examination patients. The subjects in this study were 58 Stroke medical examination patients and 58 Non-Stroke medical examination patients, and for the assessment of anxiety, depression. We used State-Trait Anxiety Inventory (STAI), Zung's Self-Rating Depression Scale(SDS). The results of this study are as follows : 1. There were significant, differences in the 16 items of State anxiety scale among 20 items and the 14 items of Trait anxiety scale among 20 items between Stroke medical examination patients and the control group(p<0.05 respectively). 2. There were significant differences in the 14 items of SDS among 20 items between Stroke medical examination patients and the control group(p<0.05 respectively). 3. There were significant differences in the mean scores of STAI and SDS between Stroke medical examination patients and the control group(p<0.001 respectively). 4. There were no significant relationships between State anxiety & Trait anxiety, State anxiety & Depression, Trait anxiety & Depression in the Stroke medical examination patients.

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Drawing up class module elements of originality and convergence and suggesting class modules by combining middle school physical education and STEAM (중학교 체육과 STEAM 융합을 통한 창의·융합 수업 모듈 요소 도출 및 수업 모듈 제시)

  • Hong, Hee-Jung;Lim, Hyun-Joo
    • Journal of Wellness
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    • v.14 no.2
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    • pp.207-223
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    • 2019
  • The purpose This study aimed at proposing class module elements for creativity and convergence and class models for creativity and convergence by integrating content elements by physical activity field(health, challenge, competition, ) for physical education and STEAM. For this, literature review, focus group interview(FGI) and discussions with experts were conducted, and the following study results have been drawn up: First, concerning the class module elements for creativity and convergence, total 11 class module elements in the health field were suggested including detecting risks by posture analysis and analyzing and designing amount of physical activity. Second, total 7 module elements in the challenge field were deduced such as anticipation of obstacles to target achievement and modeling of effective exercise. There were 17 convergence elements in the competition field including game record analysis and creation of game data storage application. Third, total 9 creativity and convergence module elements in the field include modeling of technology improvement for motion and symbolization for motion records. In addition, class modules related to convergence with engineering in the health field, convergence with technology in the challenge field, convergence with art in the competition field and convergence with art and mathematical symbols were proposed.

Biotea-2-Bioschemas, facilitating structured markup for semantically annotated scholarly publications

  • Garcia, Leyla;Giraldo, Olga;Garcia, Alexander;Rebholz-Schuhmann, Dietrich
    • Genomics & Informatics
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    • v.17 no.2
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    • pp.14.1-14.6
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    • 2019
  • The total number of scholarly publications grows day by day, making it necessary to explore and use simple yet effective ways to expose their metadata. Schema.org supports adding structured metadata to web pages via markup, making it easier for data providers but also for search engines to provide the right search results. Bioschemas is based on the standards of schema.org, providing new types, properties and guidelines for metadata, i.e., providing metadata profiles tailored to the Life Sciences domain. Here we present our proposed contribution to Bioschemas (from the project "Biotea"), which supports metadata contributions for scholarly publications via profiles and web components. Biotea comprises a semantic model to represent publications together with annotated elements recognized from the scientific text; our Biotea model has been mapped to schema.org following Bioschemas standards.

Evaluation on Usability of Space in Leed-Certified Office Building (친환경 인증 오피스 건축물의 공간 이용성 평가)

  • Kang, Inho;Park, Jung-A
    • KIEAE Journal
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    • v.14 no.4
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    • pp.103-109
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    • 2014
  • The purpose of this study was to evaluate the usability and satisfaction of space to which positive elements in Leed-Certified Office Building are applied. The study was conducted using the three-step approach. The first step was to understand the building and identify the issues which included the analysis of floor plans, documentations, and the interview with designers and facility managers. The second step was FGI(Focus Group Interviews), which were conducted with mixed employees of rank and location of workplace. Finally, a web-based questionnaire survey was conducted on the 319 executives and employees. Methods of analysis used were quantitative analysis of questionnaire, qualitative analysis of open ended free-answer, and FGI in the second step. Satisfaction, preference, and comfort level were studied using cross tab, co-relation, ANOVA for quantitative analysis. The results of this study are as follows: First, lobby and atrium are representative elements that are functioning positively and it is recognized as sustainable spaces being utilized by users. Second, there are several dead spaces like green shaft, roof garden and sunken space although they can contribute to Leed-certification. Third, there are some problematic spaces such as the O.A. room and the urinals even though they contribute to the Leed-certification.

Development and Validation of the Strengths Assessment Indicators for Daycare Centers (어린이집 강점평가지표 개발 및 타당화)

  • Hong, Sung hee;Hwang, Hae-Ik
    • Korean Journal of Childcare and Education
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    • v.14 no.6
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    • pp.143-170
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    • 2018
  • Objective: The purpose of this study was to develop assessment indicators and to verify the validity and reliability of the developed assessment indicators. Methods: A Delphi survey, focus group interviews, and content verification were conducted in order for experts to develop an evaluation index of the strengths of the day care center. A main survey was conducted on 438 daycare center principals and teachers to test their item quality, validity and reliability. Results: The final assessment indicators consisted of three areas, seven assessment criteria, 19 evaluation factors, 41 assessment items and a five-point rubric rating scale. As for the common strengths indicators, there were three assessment areas, five assessment criteria, 12 assessment elements and 22 assessment items. In regard to the selective strengths indicators, there were 3 assessment areas, 5 assessment criteria, 12 assessment elements and 16 assessment items. Conclusion/Implications: The efforts to confirm the strengths of daycare centers are expected to facilitate the identity building of the daycare center itself and for its organizational members to make a contribution to the qualitative improvement of childcare.

Determination of Rare Earth Elements in USGS Geological Materials by ICP/AES (ICP/AES에 의한 지질시료 중의 희토류원소 분석)

  • 김정석;최광순;박용준;지광용
    • Journal of the Korean Chemical Society
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    • v.39 no.2
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    • pp.28-81
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    • 1995
  • Inductively coupled plasma atomic emission spectrometry was used for the determination of all 14 rare earth elements (REE) in geological materials. Samples were decomposed by using acid digestion followed by alkaline fusion. Group separation of the REE was achieved by solvent extraction with TOPO (trioctylphosphine oxide) and back extraction into HCl. The results for standard rock sample, AGV-1, showed a good agreement with those obtained by US Geological Survey as well as reported values in other articles.

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