• Title/Summary/Keyword: Composition Test

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Synthesis of akermanite bioceramics by solid-state reaction and evaluation of its bioactivity (고상반응법에 의한 아커마나이트 분말의 합성 및 생체활성도 평가)

  • Go, Jaeeun;Lee, Jong Kook
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.32 no.5
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    • pp.191-198
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    • 2022
  • Zirconia and titanium alloys, which are mainly used for dental implant materials, have poor osseointegration and osteogenesis abilities due to their bioinertness with low bioactivity on surface. In order to improve their surface bioinertness, surface modification with a bioactive material is an easy and simple method. In this study, akermanite (Ca2MgSi2O7), a silicate-based bioceramic material with excellent bone bonding ability, was synthesized by a solid-state reaction and investigated its bioactivity from the analysis of surface dissolution and precipitation of hydroxyapatite particles in SBF solution. Calcium carbonate (CaCO3), magnesium carbonate (MgCO3), and silicon dioxide (SiO2) were used as starting materials. After homogeneous mixing of starting materials by ball milling and the drying of at oven, uniaxial pressing was performed to form a compacted disk, and then heat-treated at high temperature to induce the solid-state reaction to akermanite. Bioactivity of synthesized akermanite disk was evaluated with the reaction temperature from the immersion test in SBF solution. The higher the reaction temperature, the more pronounced the akermanite phase and the less the surface dissolution at particle surface. It resulted that synthesized akermanite particles had high bioactivity on particle surface, but it depended on reacted temperature and phase composition. Moderate dissolution occurred at particle surfaces and observed the new precipitated hydroxyapatite particles in synthetic akermanite with solid-state reaction at 1100℃.

Carrageenan-Based Liquid Bioadhesives for Paper and Their Physical Properties (카라기난 기반 액상형 바이오 종이 접착제의 제조 및 물성에 관한 연구)

  • Oh, Seung-Jun;Han, Won-Sik;Wi, Koang-Chul
    • Journal of Conservation Science
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    • v.36 no.6
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    • pp.541-548
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    • 2020
  • There is a growing demand for natural materials to replace adhesives based on volatile organic compounds (VOCs). However, the exclusion of VOCs from the manufacturing process leads to difficulties in manufacturing, and reduction in productivity and preservability. In this paper, we report the manufacture of natural bioadhesives using the carrageenan component of seaweed. λ-carrageenan, isolated from the extracted total carrageenan, was used to prepare a highly stable adhesive for paper. The resulting composition was 52.0 ± 1.0% λ-carrageenan, 30.5 ± 0.5% Polyvinylpyrrolidone, 1.0 ± 0.05% ethylhexylglycerin, 1.5 ± 0.05% glycerin, 13.5 ± 0.5% dextrine, and 0.6 ± 0.05% food-grade antifoam emulsion. The viscosity was found to be 1.13 ± 0.07 × 105 cP (25℃), UV degradation occurred at pH6.22, drying rate was 15min, △b* was -10.79, and △E* ab was 8.18. The bioadhesive showed an excellent adhesion strength of 44.63 kgf/cm2. Thus this adhesive showed excellent fungal resistance and good adhesive persistence, without the presence of total volatile organic compounds (TVOC), formaldehyde (HCHO), and heavy metals.

Features of Problem-Finding and Problem-Solving of the Secondary Gifted Students in the Context of STEAM Convergent Problems (STEAM 문제 상황에서 중등 영재반 학생들이 나타낸 문제의 발견과 해결 특성)

  • Lee, Eunseon;Sim, Jaeho
    • Journal of Science Education
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    • v.45 no.1
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    • pp.23-41
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    • 2021
  • This study is to investigate the characteristics of problem-finding and problem-solving abilities demonstrated by the secondary gifted students in the context of STEAM convergent problems. For this, using the STEAM convergence problem solving ability test, we qualitatively and quantitatively compared and analyzed the workbook outputs written in the process of finding and solving problems for each student in the gifted class. The results are as follows: First, we found that the speciality of the major of the proposed activity paper influenced the preference for questions and pattern of finding problems. Second, it was found that the difference in the ability to find and solve problems for a specific task was not by the major of the gifted class, but by the composition of the group. Third, in finding and solving the STEAM convergent problem, the individual creativity and the cooperative creativity of the group were more significant than the major. These results suggest that it is necessary to include the affective factors of gifted students and the concept of cooperation in problem-finding and problem-solving ability evaluation, and there is a need to develop a teaching and learning strategy that can improve cooperative problem-solving skills so that group creativity can be exhibited well.

Analysis of 2010s Research Trends in Research on Agro-Healing in South Korea

  • Jeong, Sun Jin;Yoo, Eun Ha;Kim, Jae Soon;Jang, Hye Sook;Lee, Geun Woo
    • Journal of People, Plants, and Environment
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    • v.23 no.3
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    • pp.267-276
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    • 2020
  • Background and objective: Agro-healing is crucial with urban farming in the domestic. It is beyond the conventional agriculture. This study was carried out to assess the 2010s researches on domestic agro-healing and predict the future direction of agro-healing development. Methods: Among the articles published from 2010 to 2018, we collected some articles by searching keywords including agro-healing, garden activity, gardening, horticultural activity, horticultural program, horticultural therapy, plant effect, plant environment, plant growing program, plant impact, social gardening, urban agriculture and vegetable garden activity, selected 83 articles that were evaluated in advance, and analyzed by frequency analysis, t-test, and one-way ANOVA with SPSS 20.0. Results: Agro-healing journal articles were published the most in 2010, and have declined since then. In the classification according to the academic society, most of the journal articles were published by the Society for People, Plants, and Environment. The main targets of domestic agro-healing related to activities and programs were preschoolers, children and adolescents, accounting for 52.4% of the total. By the characteristics of the subjects, agro-healing programs and studies were conducted with special participants who needed special care compared to the general participants. The dependent variables were classified into six areas according to their attributes and the share of psychological and emotional areas was highest (42.6%) among them. In terms of the composition of the program, the share of those with 9-12 sessions was highest (36.7%) and the share of those with more than 20 participants was also highest (39.8%). Conclusion: It is recommended to operate agro-healing programs or industries focusing on the socially disadvantaged including those who have special needs or the underprivileged, but in order to create income for farms and expand the demand for agro-healing, it will be necessary to spread the perception that anyone without any physical or emotional issue can be the targets of and experience agro-healing. To meet the different needs of targets of agro-healing, it will be necessary to conduct objective and practical studies on broader areas and in the process the healing functions of agriculture and the strength of agro-healing needs to be further highlighted.

Effects of Protein Intake on Sarcopenia Prevention and Physical Function of the Elderly in a Rural Community of South Korea During the COVID-19 Pandemic (COVID-19시대 한국 농촌 지역 노인의 단백질 섭취가 근감소증 예방 및 신체기능에 미치는 영향)

  • Li, Xinxing;Kim, Hee-Jae;Kim, Dae-Young;Zhang, Yanjie;Seo, Ji-Won;Ahn, Seo-Hyun;Song, Wook
    • Journal of The Korean Society of Integrative Medicine
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    • v.10 no.2
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    • pp.37-47
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    • 2022
  • Purpose : We aimed to investigate the effects of nutritional foods on sarcopenia prevention and physical function among the elderly living in rural communities during the COVID-19 pandemic by providing customized nutrition. Methods : This study was conducted in the rural community of SCC. Participants (n=24, over age 65) were randomly assigned into a Protein group (n=12) and a Vitamin group (n=12). The protein group was given 23 g/d of protein (whey, soybean, BCAA) for 8 weeks and the Vitamin group 23 g/d of vitamin (B, C, D, E and mixed minerals such as calcium, magnesium, zinc) for 8 weeks. All participants had their body composition such as height, weight, skeletal muscle mass, body mass index, and body fat percentage, measured using bioelectrical impedance analysis (BIA) and physical function assessed using grip strength and the short physical performance battery (SPPB). Results : At the end of the intervention, there was a significant increase in skeletal muscle mass (p<.01) in the Protein group (p=.002, 4.92 %) compared to the baseline: it increased by 2.33 %. The Vitamin group had a significant increase in body fat percentage after the intervention (p=.001, 15.35 %) compared to the baseline: body fat percentage decreased by 4.49 %. There were no significant differences in left and right Grip strength/Weight, SPPB, 4-m gait speed, chair stand test, and sense of balance in both groups. Conclusion : The findings from this study suggest that 8 weeks of protein intake have a significant effect on skeletal muscle mass and body fat percentage. Protein intake helped promoting the health of the elderly in rural community during the COVID-19 pandemic. It will assist creating a foundation for providing customized nutrition for the elderly in rural community in the future.

An Experimental Study for the Development of Soil Injection Materials using Vietnam's Circulating Resources (베트남 순환자원을 활용한 지반주입재 개발을 위한 실험적 연구)

  • Young-Won, Lee;Kwang-Wu, Lee;Se-Gwan, Seo;Wan-Kyu, Yoo;Jae-Hyun, Park
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.10 no.4
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    • pp.457-464
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    • 2022
  • In this study, XRF, Loss on ignition, SEM, and PSA analysis were performed on four types of fly ash in Vietnam and compared with fly ash in Korea. As a result, PC boiler fly ash in Vietnam has a similar chemical composition to that of PC boiler fly ash in Korea, where the content of SiO2, Al2O3, and Fe2O3 accounts for about 70%. In addition, the result showed that blast furnace slags in Vietnam and Korea have similar quality criteria and performance. A binder material mixing test using four types of fly ash supplied from Vietnam was conducted, and the compressive strength ranged from 7.60 to 13.25 MPa after 28 days of curing. Vinh Tan fly ash showing the highest compressive strength was selected as the soil injection material for the chemical grouting method. For the formulation of the chemical grouting method, sodium silicate No.3 and silica-sol were used as liquid-A. As a result of measuring the gel time and the compressive strength of the homogel, they showed good performance satisfying the quality criteria applied in Korean construction fields. Therefore, Vinh Tan fly ash can be used as a soil injection material for the chemical grouting method.

A Study on the Effects of Dang Dang Integrated Corrective Therapy (당당통합교정치료의 효과에 대한 연구)

  • Sung, Jin-Wook;Jang, Hong-Gyu;Cho, Won-Nyeong;Seo, Jong-Gil;Kim, Byeong-Jin;Ko, Min-Joo
    • Journal of The Korean Society of Integrative Medicine
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    • v.10 no.1
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    • pp.13-26
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    • 2022
  • Purpose : The purpose of this study was to investigate the effect of Dang Dang integrated corrective therapy including myofascial release, chuna therapy, and exercise therapy on height, muscle mass, body fat, and body water in patients with body imbalance. The secondary aim was to investigate whether the percent of change in height, muscle mass, body fat, and body water varied by age group. Methods : In total, 279 patients with body imbalance between the ages of 10 and 79 were recruited at hospitals. All participants had Dang Dang integrated corrective therapy including myofascial release, chuna therapy, and exercise therapy. The patients' height, muscle mass, body fat, and body water were measured before and after Dang Dang integrated corrective therapy using InBody. Results : The height, muscle mass, and body water significantly increased after Dang Dang integrated corrective therapy in all age groups except for the 70~79 age group and body fat significantly decreased (p < .05). The age group comparison of the percent change in height, muscle mass, and body water showed significant differences (p < .05). In the post hoc test, the percent change of height in the 10~19 age group was significantly greater than in the other age groups except for the 70~79 age group. The percent change of muscle mass and body water in the 10~19 age group was significantly greater than in the 30~39 age group. Conclusion : These findings suggest that applying Dang Dang integrated corrective therapy to patients with body imbalance, excluding patients aged 70~79, may be a useful method to increase height, muscle mass, and body water and decrease body fat through spinal and joint realignment. The best results were observed in teenagers.

BEEF MEAT TRACEABILITY. CAN NIRS COULD HELP\ulcorner

  • Cozzolino, D.
    • Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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    • 2001.06a
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    • pp.1246-1246
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    • 2001
  • The quality of meat is highly variable in many properties. This variability originates from both animal production and meat processing. At the pre-slaughter stage, animal factors such as breed, sex, age contribute to this variability. Environmental factors include feeding, rearing, transport and conditions just before slaughter (Hildrum et al., 1995). Meat can be presented in a variety of forms, each offering different opportunities for adulteration and contamination. This has imposed great pressure on the food manufacturing industry to guarantee the safety of meat. Tissue and muscle speciation of flesh foods, as well as speciation of animal derived by-products fed to all classes of domestic animals, are now perhaps the most important uncertainty which the food industry must resolve to allay consumer concern. Recently, there is a demand for rapid and low cost methods of direct quality measurements in both food and food ingredients (including high performance liquid chromatography (HPLC), thin layer chromatography (TLC), enzymatic and inmunological tests (e.g. ELISA test) and physical tests) to establish their authenticity and hence guarantee the quality of products manufactured for consumers (Holland et al., 1998). The use of Near Infrared Reflectance Spectroscopy (NIRS) for the rapid, precise and non-destructive analysis of a wide range of organic materials has been comprehensively documented (Osborne et at., 1993). Most of the established methods have involved the development of NIRS calibrations for the quantitative prediction of composition in meat (Ben-Gera and Norris, 1968; Lanza, 1983; Clark and Short, 1994). This was a rational strategy to pursue during the initial stages of its application, given the type of equipment available, the state of development of the emerging discipline of chemometrics and the overwhelming commercial interest in solving such problems (Downey, 1994). One of the advantages of NIRS technology is not only to assess chemical structures through the analysis of the molecular bonds in the near infrared spectrum, but also to build an optical model characteristic of the sample which behaves like the “finger print” of the sample. This opens the possibility of using spectra to determine complex attributes of organic structures, which are related to molecular chromophores, organoleptic scores and sensory characteristics (Hildrum et al., 1994, 1995; Park et al., 1998). In addition, the application of statistical packages like principal component or discriminant analysis provides the possibility to understand the optical properties of the sample and make a classification without the chemical information. The objectives of this present work were: (1) to examine two methods of sample presentation to the instrument (intact and minced) and (2) to explore the use of principal component analysis (PCA) and Soft Independent Modelling of class Analogy (SIMCA) to classify muscles by quality attributes. Seventy-eight (n: 78) beef muscles (m. longissimus dorsi) from Hereford breed of cattle were used. The samples were scanned in a NIRS monochromator instrument (NIR Systems 6500, Silver Spring, MD, USA) in reflectance mode (log 1/R). Both intact and minced presentation to the instrument were explored. Qualitative analysis of optical information through PCA and SIMCA analysis showed differences in muscles resulting from two different feeding systems.

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Preparation and Properties of Hollow Fiber Membrane for CO2/H2 Separation (이산화탄소/수소 분리용 중공사형 기체분리막의 제조 및 특성)

  • Hyung Chul Koh;Mi-jin Jeon;Sang-Chul Jung;Yong-Woo Jeon
    • Membrane Journal
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    • v.33 no.4
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    • pp.222-232
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    • 2023
  • In this study, a hollow fiber support membrane was prepared by a non-solvent induced phase separation (NIPS) method using a polysulfone (PSf). The prepared hollow fiber support membrane was coated with PDMS and Pebax to prepare a hollow fiber composite membrane. The prepared composite membrane was measured for permeance and selectivity for pure CO2, H2, O2 and N2. Gas separation performance of the module having the highest selectivity (CO2/H2) among the prepared composite membrane modules was measured according to the change in stage cut using simulated gas. The composition of the simulated gas used at this time was 70% CO2 and 30% H2. In the 1 stage experiment, it was possible to obtain values of about 60% of H2 concentration and 12% of H2 recovery. In order to overcome the low H2 concentration and recovery, 2 stage serial test was performed, and through this, it was possible to achieve 70% H2 concentration and 70% recovery. Through this, it was possible to derive a separation process configuration for CO2/H2 separation.

A Study of Transient Liquid Phase Bonding with Ni-foam/Sn-3.0Ag-0.5Cu Composite Solder for EV Power Module Package Application (Ni-foam/Sn-3.0Ag-0.5Cu 복합 솔더 소재를 이용한 EV 파워 모듈 패키지용 천이 액상 확산 접합 연구)

  • Young-Jin Seo;Min-Haeng Heo;Jeong-Won Yoon
    • Journal of the Microelectronics and Packaging Society
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    • v.30 no.1
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    • pp.55-62
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    • 2023
  • In this study, Sn-3.0Ag-0.5Cu (wt.%, SAC305) solder dipping process was performed between Ni-foam skeleton with different pore per inch (PPI) to fabricate Ni-foam/SAC305 composite solder, and then applied to the transient liquid phase (TLP) bonding process to evaluate the microstructure and mechanical properties of the bonded joint. The Ni-foam/SAC305 composite solder preform consisted of Ni-foam and SAC305, and an intermetallic compound (IMC) having a (Ni,Cu)3Sn4 composition was formed at the Ni-foam interface. During TLP bonding process, the IMC at the Ni-foam interface was converted to (Ni,Cu)3Sn4+Au, and as the bonding time increased, the Ni-foam and SAC305 continuously reacted, and the bonded joint was converted into an IMC. And it was confirmed that the 130 PPI Ni-foam/SAC305 composite solder joint was converted into an IMC at the fastest rate. As a result of performing a shear test to confirm the effect of Ni-foam on mechanical properties, solder joints under all conditions exhibited excellent mechanical properties of 50 MPa or more in the early stages of the TLP bonding process, and the shear strength tends to increase as the bonding time increases.