In this study, we evaluated the effects of acid leaching on the properties of Cr powder synthesized using self-propagating high-temperature synthesis (SHS). Cr powder was synthesized from a mixture of Cr2O3 and magnesium (Mg) powders using the SHS Process, and the byproducts after the reaction were removed using acid leaching. The properties of the recovered Cr powder were analyzed via X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), particle size analysis (PSA), and oxygen content analysis. The results show that perfect selective leaching of Cr is challenging because of various factors such as incomplete reaction, reaction kinetics, the presence of impurities, and incompatibility between the acid and metal mixture. Therefore, this study provides essential information on the properties under acidic conditions during the production of high-quality Cr powder using a self-propagating high-temperature synthesis method.
Rare earth elements, which are important components of motors, are in high demand and thus constantly get more expensive. This tendency is driven by the growth of the electric vehicle market, as well as environmental issues associated with rare-earth metal manufacturing. TC 298 of the ISO manages standardization in the areas of rare-earth recycling, measurement, and sustainability. Korea, a resource-poor country, is working on international standardization projects that focus on recycling and encouraging the domestic adoption of international standards. ITU-T has previously issued recommendations regarding the recycling of rare-earth metals from e-waste. ISO TC 298 expands on the previous recommendations and standards for promoting the recycling industry. Recycling-related rare earth standards and drafts covered by ISO TC 298, as well as Korea’s strategies, are reviewed and discussed in this article.
This study was performed to improve the effectiveness of dietary education using a food ethics approach. Dietary education is a way of practicing food ethics based on Korean culture. The core values of dietary education and the keywords related to food ethics can be combined into environment · life, health · wisdom, and consideration · happiness. Sustainable dietary life comprises the value system of dietary education based on core values. To reach the ultimate goal of food ethics -sustaining the survival of the human race, the coexistence of humans and nature, the coexistence of humans and humans, and the fulfillment of food requirements are needed. These needs yield certain core principles, including respect for life, environmental preservation, justice, the priority of consumers, dynamic equilibrium, and the priority of safety. The extended ethical matrix with six core principles and three interest groups can be used for an ethical analysis either qualitative or quantitative. It is believed that if food ethics are introduced into dietary education programs, the effectiveness of education can be improved.
Since the ISO decided to deal with rare-earth elements at the 298th Technical Committee (TC) in 2015, Korea has participated in four plenary meetings and proposed four standards as of June 2019. The status of ISO TC 298, the standards covered by the TC, and the standardization strategies of Korea are summarized. Korean delegations are actively engaged in WG2, which deals with recycling, proposing four standards for fostering the rare-earth recycling industry. However, the participation of domestic experts is still low compared with the increase in the number of working groups and the number of standards in TC 298. The aim of this article is to summarize the current status of ISO international standards related to rare-earth elements, to encourage relevant experts to participate in standardization, and to develop international standards that accurately reflect the realities of the industry.
The purposes of this study are to analyze high-frequency hedges in dissertations and provide basic data for Korean education for academic purposes. For these purposes, the investigator analyzed ‘-(으)ㄹ 수 있 다, -(으)ㄹ 것이다, and -(으)로 보이다’ in terms of frequency, distribution by the structure, and forms of combination in 50 dissertations for a master’s degree. The findings were as follows: first, ‘-(으)ㄹ 수 있다, -(으)ㄹ 것이다, and -(으)로 보이다’ were used total 3,880 times across all the dissertations. Of them, ‘-(으)ㄹ 수 있다’ were used 2,496 times, recording an overwhelmingly higher frequency than the others. Secondly, the study analyzed the frequency of hedges by the part in dissertations and found that hedges were most used in “Findings”(56.6%). Finally, there were standardized forms frequently combined with each hedge. ‘-(으)ㄹ 수 있다,’ for instance, was frequently used in the forms of ‘-(이)라고 할 수 있다/다고 할 수 있다,’ ‘-(으)ㅁ을 알 수 있다,’ and ‘-다는 것을 알 수 있다.’
Owing to increasing demand of rare metals present in ICT products, it is necessary to promote the rare metal recycling industry from an environmental viewpoint and to prevent climate change. Despite the fact that information for toxic substances is partly indicated, a legal basis and an international standard indicating usage of rare metals is insufficient. In order to address this issue, a newly created study group of environment and climate change at the ITU (International Telecommunication Union) is doing research to develop methodologies for recycling rare metals from ICT products in an eco-friendly way. Under this group, the Republic of Korea has established two international standards related to rare metals present in ICT products. The first is ‘Release of rare metal information for ICT products (ITU-T L.1100)’ and the other is ‘Quantitative and qualitative analysis methods for rare metals (ITU-T L.1101)’. A new proposal for recommending the provision of rare metal information through a label by manufacturers and consumer/recycling businesses has been approved recently and is supposed to be published later in 2016. Moreover, these recommendations are also being extended to IEC, ISO and other standardization organizations and a strategy to reinforce the ability for domestic standardization is being established in accordance with industrial requirements. This will promote efficient recycling of rare metals from ICT products and will help improve the domestic supply of rare metals.
The Korea Immigration & Integration Program (KIIP) by the Ministry of Justice offers social integration education in order to educate immigrants about Korean language and culture. This paper presents a case study on the development of Korean language textbooks for KIIP. Korean Language and Culture for Immigrants (Intermediate Levels 1 and 2) is used as a teaching material at 308 social integration education institutions. This paper introduced its development procedure and method, its development directions, the organization of its syllabus, and the content of its units. Its development process involved analyzing purposes of social integration education and of needs of incumbent teachers to develop a teaching material to meet the goals of social integration. Efforts were made to closely connect the content of Korean study to that of culture study with a focus on making culture study lead to an overall understanding of South Korean society and to serve fully as a preparation process to acquire Korean nationality. This paper will hold its value as a guideline to be consulted for the development of Korean language textbooks for immigrants and help teachers make efficient use of textbooks according to the objectives of education in a social integration program.
This study aims to analyze the aspect of coherence realization of narrative discourse of female marriage immigrants. Considering that discourse structure and cohesive devices are engaged in the coherence of discourse, this study attempts to examine the aspect of structure development of narrative discourse and the utilization of reference and conjunction. The participants in the study are intermediate and advanced-level female marriage immigrants. The analysis results of this study can be summarized as follows: (1) the female marriage immigrants selectively contained [abstract] and [evaluation] while essentially containing [setting], [complicating action], [resolution] when comprising narratives; the coherence of discourse was found to be disrupted due to insertion of extraneous contents, lack of information, excess of information, or delaying of the introduction utterances; (2) the use of cohesive devices was concentrated in a particular expression. Suggestions based on the findings of the study are provided.
This study was conducted to investigate the use of sugar alcohols (sorbitol, erythritol, and xylitol) as alternative sweeteners for replacing sucrose in Yukwa (traditional Korean oil-puffed rice snack). The moisture contents of Bandegi (dried Yukwa dough) and Yukwa containing sugar alcohols were higher than that of control (containing only sucrose). The microstructures of control and Bandegi containing sugar alcohols showed uniformly and finely distributed air holes. Expansion ratio and oil absorption of Yukwa containing sorbitol and 30% erythritol were higher than those of control. Appearance and cross section of control and Yukwa containing sorbitol, 30% erythritol, and 30% xylitol showed a good shape. The lightness (L) of control was significantly lower than Yukwa containing sugar alcohols, whereas redness (a) and yellowness (b) were higher than those in Yukwa containing sugar alcohols. Hardness of Yukwa containing sugar alcohols was significantly lower than that of control, and that of Yukwa containing sorbitol was the lowest. Peak number of Yukwa containing sugar alcohols was significantly lower than that of control, and that of Yukwa containing 60% erythritol and 60% xylitol was the lowest among all samples. In the sensory evaluation, color of control was deepest, whereas that of Yukwa containing 60% xylitol was lightest. Volume and air hole uniformity of Yukwa containing 60% erythritol and 60% xylitol were inferior than those of other samples. Sweetness of Yukwa containing sugar alcohols was lower than that of control, whereas oily flavor was stronger. Hardness of Yukwa containing sugar alcohols was lower than that of control, and Yukwa containing xylitol showed the lowest hardness among the samples. Crispness of Yukwa containing sugar alcohols was lower than that of control. There were no significant differences in overall acceptability between control and Yukwa containing 30% sorbitol and 30% erythritol. Overall, sorbitol and erythritol were appropriate as a 30% replacement for sucrose when preparing Yukwa.
The purpose of this study is to examine the effects of focus-on-form approach on learning connective ending '-느라고' of Korean language learners. Input enhancement and consciousness raising tasks were applied and compared as an effective way of this grammar instruction among various techniques of focus-on-form approach. The participants in the study are intermediate-level Korean language learners. They were divided into two groups, and teaching activities were provided undertaken based on two different methods. According to the results, significant differences were not found between the two methods, but the upper-level students had higher achievements than the lower-level students. Although no significant difference was found between the input enhancement and consciousness raising tasks, it was found that the focus-on-form approach can be recommended as a way to teach grammar effectively, especially it is effective for upper-level learners.
This study was carried out to determine the quality characteristics of Jeju mandarin orange jellies containing sugar (control) and sugar derivative sweeteners (erythritol, isomaltooligosaccharide, sorbitol, and xylitol) to be consumed by the elderly. The gelling agents were carrageenan and gellan gum at the concentration of 0.27%, respectively. The average age of the subjects for the acceptance test was 78. The lightness (L), redness (a), and yellowness (b) values of the carrageenan gel were higher than those of the gellan gum gel using the same sugars. The L, a, and b values of the carrageenan gel made with sugar derivative sweeteners were higher than those of the respective gel made with sugar. Whereas there were almost no differences between the color values of the gellan gum gels made with sugar and sugar derivative sweeteners, respectively. The gelling and melting temperatures of the carrageenan gel with erythritol were highest and those of the respective gel with xylitol were lowest among the sugar derivative sweeteners. The gelling and melting temperatures of the gellan gum gels with erythritol and isomaltooligosaccharide, respectively, were lower, and those of the respective gel made with xylitol were higher compared to that with sugar. There was no break down in the gellan gum gel. The break down rate of the carrageenan gel made with isomaltooligosaccharide was highest and that of the respective gel with xylitol was lowest among the sugar derivative sweeteners. The hardness, adhesiveness, springiness, and chewiness of the gellan gum gel were greater compared to the carrageenan gel. The adhesiveness levels of the carrageenan gels made with sugar derivative sweeteners were lower, and their springiness was higher than the respective gel with sugar. All the TPA characteristics of the gellan gum gels made with erythritol and xylitol, respectively, were higher than the respective gel with sugar. The rupture properties of the gels were the same as their TPA characteristics. The sensory acceptance of the carrageenan and gellan gum gels made with sugar were highest among all the sweeteners. There were no significant differences in the sensory acceptance scores of the carrageenan gels made with xylitol, erythritol, and sugar, respectively, and there were also no significant differences in the sensory acceptance scores of the gellan gum gels made with xylitol, sorbitol, and sugar, respectively. Xylitol was preferred in both the carrageenan and gellan gum gels. Thus, xylitol appears to be an appropriate alternative sweetener to sugar in Jeju mandarin orange jelly for consumption by the elderly, with regard to the acceptability and stability of the gel.
This study was conducted to determine the quality characteristics of grape jellies for the elderly. The jellies contained sugar (control) or sugar derivative sweeteners (erythritol, isomaltooligosaccharide, sorbitol, and xylitol). Agar (0.31%) and k-carrageenan (0.27%) were the gelling agents. The average age of the subjects participating in the acceptance test was 79. The lightness (L), redness (a), and yellowness (b) values of the agar gel with erythritol mostly decreased, indicating a darker and pale red color. The L and b values of the carrageenan gel with sugar derivative sweeteners increased, indicating brighter and yellowish color. The agar and carrageenan gels with sorbitol showed higher gelling and melting temperature, indicating that gelation occurred easily and did not easily melt. The agar and carrageenan gels with xylitol showed a low-melting temperature, indicating low stability with temperature change. The break-down rate of the agar and carrageenan gels with erythritol was low, whereas that of agar gel with sorbitol was relatively high despite its high melting temperature. Hardness, cohesiveness, gumminess, and chewiness of the gels with sugar derivative sweeteners decreased, and this tendency was most distinct with isomaltooligosaccharide in the agar gel and with sorbitol in the carrageenan gel. The rupture properties of the gel were the same as the hardness of the gel. Sensory acceptance of the agar gels with erythritol, sorbitol, isomaltooligosaccharide, and the carrageenan gel with erythritol was fairly high, whereas that of the agar gel with xylitol and the carrageenan gel with isomaltooligosaccharide and xylitol was low. The results show that sorbitol and erythritol are appropriate as sugar substitutes in grape jellies for the elderly about the acceptability and stability of the gels.
The quality characteristics of cookies containing brown rice flour, which has a greater variety of functional components than wheat flour, were studied. The results of the pasting properties shows that the inclusion of brown rice flour to the wheat flour-mixture did not affect the pasting temperature for up to 30% inclusion. The total dietary fiber and total polyphenol content increased and color of the cookies became darker with increasing brown rice flour content. According to the results from TA on texture, the hardness decreased and the crispness increased significantly(p<0.001, p<0.05, respectively) with increasing brown rice flour content. From the acceptance test, the aroma and texture of the cookies with added brown rice flour were significantly(p<0.001) lower than those of the wheat flour cookies. However, the appearance, taste, and overall acceptance of the cookies with added brown rice flour did not differ significantly from those of the wheat flour cookies. According to the results from the sensory evaluation, the savory aroma of the cookie with 30% brown rice flour was significantly strong(p<0.001). The brown rice flavor of the cookies with brown rice flour was significantly stronger(p<0.001) than that of the wheat flour cookie, but there were no significant differences among the cookies with brown rice flour in it. The crispness of the cookies increased significantly(p<0.001) with the inclusion of brown rice flour in the mixture, especially for the mixture with 30% brown rice flour which had the highest value of crispness among the cookies. The graininess and brown color of the cookies increased significantly(p<0.001) with increasing brown rice flour content, especially for the mixture with 30% brown rice flour which had the highest values among the cookies.
Photo-crosslinkable polyimide(PI) which contains CF3 moiety was synthesized. Polarized UV light transformed ketone group of PI to hydroxyl group, which was confirmed by IR and UV-visible spectroscopy. We investigated the dichroic UV-absorption before and after photo-reaction with linearly polarized light. In particular we have attempted to clarify the relationship between the anisotropy of surface region and surface azimuthal anchoring energy and knew that the anchoring energy of photo-alignment PI is comparable with that of mechanical rubbing.