• 대한화학회지
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• 제47권2호
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• pp.155-164
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• 2003

이 연구에서는 물리변화와 화학변화에 대한 중${\cdot}$고등학교 과학교사들의 인식을 조사한 선행연구 결과를 바탕으로 과학교과서에서는 두 변화에 대해 어떻게 정의하고 있는지 살펴보았다. 이 연구를 위해 중학교 2학년 과학교과서부터 고등학교 화학교과서에 이르기까지 총 44종의 교과서를 분석하였다. 과학교과서 분석 결과, 물리변화와 화학변화에 대한 개념이 제시되어 있지 않거나, 제시되어 있다 할지라도 성질유형의 설명에 치우쳐 있었다. 또한 물리변화와 화학변화가 관련되어 설명이 이루어지지 않았고, 제시된 물리변화의 예들이 화학변화의 예들과 혼동되었다. 이러한 서술내용은 물리변화와 화학변화를 배우는 학생들과 가르치는 과학교사들에게 혼란을 유발시킬 가능성이 있다. 따라서 물리변화와 화학변화에 대한 과학교과서의 진술방식을 정확하고 일관성 있는 설명체계로 재구성할 필요가 있다.

• Journal of the Korean Wood Science and Technology
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• 제50권1호
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• pp.31-45
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• 2022

After manufacturing the natural dyed actual size Hanji using 11 kinds of plant natural dyeing materials and 2 kinds of animal natural dyeing materials, the color characteristics and color change and color fastness after post-mordanting were compared and discussed. The hues of 13 types of natural dyed Hanji were black, PB, and RP, each with 1 type, YP with 3 types, and Y with 7 types. Among the natural dyeing materials, Chinese ink, indigo and Lac showed high color yield and color difference, and violet-root cromwell and gardenia seeds showed low color yield. The color fastness of Hanji dyed with turpentine diluted Ottchil, Pagoda tree seeds, Chinese ink and indigo was excellent, while that of gardenia seeds and violet-root cromwell were very poor. After post-mordanting of natural dyed Hanji with Al, Cu, and Fe mordants, the hue changes were show up the Alnus firma, clove, lac and cochineal. In addition, the color difference was very diverse and was overall the most biggest due to Fe mordant. After 72 hr. of UV irradiation on post-mordanting natural dyed Hanji, hue change was observed in 3 types and color fastness was improved in 8 types by post-mordanting. The Hue and color fastness are significantly different depending on the type of natural dying materials and post-mordants. Therefore, when dyeing Hanji with natural dyes, it is necessary to dye with sufficient knowledges and informations about the desired color and fastness.

• 한국농림기상학회지
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• 제15권2호
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• pp.85-101
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• 2013

본 연구는 논, 밭, 과수원, 도로변에 생육하고 있는 식물상을 조사하여 $C_4$식물의 분포특성을 규명하고자 하였다. 현장조사는 2002년부터 2006년까지 5년간 수행되었다. 그 결과, 총 74과 231속 352종이 확인되었으며, 쌍자엽식물 255종, 단자엽식물 89종, 양치식물 8종으로 분류되었다. 농경지유형별로는 논에서 55과 203종, 밭에서 49과 218종, 과수원에서 44과 115종, 도로변에서 48과 202종이 출현하였다. 본 조사를 통하여 논은 쑥과 고마리, 밭과 도로변은 쑥과 개망초, 과수원은 닭의장풀과 바랭이로 대표되며 농업생태계에서 출현율이 가장 높은 식물은 쑥으로 확인되었다. 또한, 출현식물 중 $C_4$식물은 8과 25속 38종으로 확인되었으며, 논, 과수원, 도로변에서는 $C_4$ 단자엽식물의 출현율이 높았으며 밭에서는 다른 농경지유형에 비해 쌍자엽식물의 출현빈도가 높았다. 이러한 $C_4$식물의 출현율 차이는 고온 건조한 우리나라 밭 주변 식물서식환경을 반영하고 있으며, 논과 과수원은 상대적으로 습윤한 미기후조건에서 건조조건이 아니라 온도조건에 의해 $C_4$ 단자엽식물이 분포하는 것으로 생각되었다. 또한 농업생태계를 대표하는 $C_4$식물 중 단자엽식물은 바랭이와 닭의장풀이며 쌍자엽식물은 개비름과 명아주로 확인되었다. 본 조사에서 총 47종의 귀화식물이 확인되었으며 토양의 수분환경조건이 상대적으로 건조한 밭과 도로변에서 많은 귀화식물이 출현하였다. 귀화식물 가운데 $C_4$ 식물은 비름속의 개비름과 털비름 2종으로 나타났으며, 단자엽식물은 관찰되지 않았다. 본 연구에서는 농경지유형에 따른 대표적인 $C_4$식물의 분포특성이 확인되었으며 지구온난화로 인한 기온의 상승으로 고온에 적응성이 높은 $C_4$식물의 새로운 유입과 이미 유입된 종 가운데 농업생태계에 나쁜 영향을 미칠 수 있는 외래식물의 확산에 대한 장기적인 모니터링의 필요성을 제안하였다.

• 한국초등과학교육학회지:초등과학교육
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• 제31권3호
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• pp.298-310
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• 2012

The purpose of this study was to analyze the characteristics of elementary school students' prediction changes by the suggestion types in a multiple anomalous situation. We investigated the responses, the rate and time of changing prediction, and cognitive conflicts of the students when repeated anomalous situation was suggested in experimental or logical way in science classes focused on buoyancy. As the anomalous situation was repeated, the students to change the prediction increased in number and also the rates to choose the correct prediction became higher. The group who was exposed in experimental way changed their prediction more than in logical way. In addition, when we classified the students to change the prediction by types, the group in experimental way showed higher rate of NM, MM type and FFT type. With anomalous situation repeated, cognitive conflicts of the students has been gradually declining in both groups. But it seemed that the group in experimental way experienced higher mental conflicts. In particular, as students changed the prediction more and arrived at the correct answer after changing their prediction, all the more so. It is concluded that the degree of students' changing prediction and experiencing cognitive conflict can be different according to the suggestion types for situation. Therefore the correlation with cognitive conflict factors can be also observed with the types of students' reactions.

• 한국환경과학회지
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• 제25권9호
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• pp.1269-1281
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• 2016

This study evaporative cooling system a heat wave climate change and reduction of the inside and outside thermal environment change research. Measurement items included micro meteorological phenomena and measured comfort indices. A micro meteorograph of temperature, relative humidity, surface temperature, and the comfort indices of WBGT, UTCI, and PMV were measured. The difference in inside and outside temperatures were compared for different land types, with the largest difference found in Type A ($4.81^{\circ}C$), followed by Type B ($4.40^{\circ}C$) and Type C ($3.12^{\circ}C$). Relative humidity was about 10.43% higher inside due to water injection by the evaporative cooling system. Surface temperature was inside about $6.60^{\circ}C$ higher than the outside all types. WBGT were Type A ($3.50^{\circ}C$) > Type B ($2.71^{\circ}C$) > Type C ($1.88^{\circ}C$). UTCI was low heat stress inside than outside all types. PMV was analysed Type C for inside predicted percentage of dissatisfied 75%, other types was percentage of dissatisfied 100% by inside and outside. Correlation analysis between land cover type and temperature, surface temperature, pmv, utci. T-test analysed inside and outside temperature difference was significant in all types of land.

• 치위생과학회지
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• 제22권3호
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• pp.148-155
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• 2022

Background: The use of dental floss along with a toothbrush is a well-known oral hygiene product that effectively removes dental plaque and reduces the risk of dental caries and periodontal disease. Despite the fact that various types of floss are being used, flossing methods based on the thread type are being taught. In addition, personal preference according to the floss types has not been investigated. In this study, individual preferences according to the floss types were investigated by experiencing various types of dental floss to both floss users and non-users. In addition, the change in intention to use dental floss in the future after flossing experience of non-users was investigated. Methods: General public participated in the individual interview survey (n=419). Subjects responded to the questionnaire after using all of the thread type, Y-type, and C-type floss. All statistics were expressed frequencies and percentages for categorical variables, and the chi-squared test was used to determine the statistical significance of associations between the variables. Results: As a result of the analysis, the preference of C-type floss was highest in both floss users and non-users. The biggest reason for not using dental floss was not knowing the necessity of flossing (36.4%). In addition, both floss users and non-users responded that C-type floss was suitable for flossing in the anterior and posterior regions. The change in the positive future intention to use dental floss after flossing experience of non-users was statistically significantly associated with age. Conclusion: This result suggests that there is a need to provide education on how to use dental floss in various forms. Based on this, it will be possible to lead a change in individual's attitude for future oral health through active and continuous flossing experience.

• International Journal of Internet, Broadcasting and Communication
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• 제12권4호
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• pp.137-147
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• 2020

The Corona 19 pandemic is bringing a big change in the fields of politics, economy, society, culture, environment, ecosystem, science and technology, and business management activities and advertising. Therefore, in this study, after the Corona 19 pandemic, we predicted how the characteristics of future advertising and the types of future advertising will change, and we studied countermeasures. We used, a method of analyzing related literature and the Delphi Survey method predicting the future, as a research method. As expert Panel, the subject of the Delphi technique survey, we recruited 30 experts in the field of advertising and future fields with professional insight. We study to predict how the characteristics of future advertising and the types of future advertising will change according to changes in the advertising environment such as social changes, business changes, and consumer changes after the Corona 19 pandemic. In order to cope with these changes in future advertising, it is necessary to actively prepare the advertising industry and advertising experts. Therefore, we suggested countermeasures so that the advertising industry and advertising experts can understand and respond for future advertising changes.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2007년도 추계 학술논문 발표대회
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• pp.95-98
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• 2007

This study investigates the mechanical properties of the high strength concrete in the region of 80MPa corresponding to the temperature and fiber content change. For the properties of the fresh, slump flow is $600{\pm}100mm$, and air content is $3.0{\pm}1.0%$. They satisfy each targets, and there was no difference for the each fiber types. As the propertied of the hardened concrete, the compressive strength at 28 days is indicated over 80MPa, and they are similar to the change of the fiber types. The residual compressive strength in response to the temperature change of the NY, PP, and NY+PP fiber at $200^{\circ}C$ are increased by 115, 114, and 110% on the standard condition, and it is suddenly decreased at $400^{\circ}C$. They are decreased by 33, 19, and 16% on the standard condition at $800^{\circ}C$.

• 한국입자에어로졸학회지
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• 제19권1호
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• pp.1-11
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• 2023

Respiratory face masks are protective facepieces that are designed to filter inhaled air. They are easy-to-use devices that can protect the wearer against various hazardous particles in the air. Respiratory face masks also prevent the spread of viruses and bacteria-containing droplets that are released from the coughing or sneezing of the infected people. During the COVID-19 pandemic, various types of face masks have circulated on the market. Their ability to filter sub-micron particles, which are the sizes of harmful particulate matter and airborne viruses, needs to be investigated. Their breathability, the easiness of breath through the mask, also needs to be considered. In this study, wwe evaluated the performance of filters used for different types of face masks certified by different standards including Korean (KF94, KF80, KF-AD), USA (N95), and Chinese (KN95) standards. We also tested the filters of nanofiber masks and surgical masks for which there are no standards for filtration test. The N95 mask filters showed the highest quality factor for capturing virus-sized particles. The other types of mask filters have acceptable performance except for nanofiber mask filters whose performance is very low.

• 복식문화연구
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• 제7권2호
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• pp.257-274
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• 1999

Clothing care has been changed with the times condition of clothing to social and economic background. Nowadays, it needs reasonable and saving clothing care for home economy under the IMF structure. Therefore, the purpose of this study is to find out development and proper type of clothing care at the present to change of clothing in the newspaper from 1910 to 1998. The development of clothing care can be divided five steps as clothing care in home, spare clothing care, clothing care in the professional shop, re-used clothing care, economic clothing care. This study classified types of clothing care to typical purpose from these five steps. Results were as follows; The types of clothing care are for long wearing, reduction of clothing expenses and domestic duties, new designed clothes from unused clothes, re-use preserving environment. The practice of reasonable and economic clothing care at the present is desirable for reference clothing care in the past.