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산 처리와 pH 조절을 이용한 사문석군 광물로부터 규소와 철산화물 회수 및 광물 탄산화 연구
백지연,조연우,이정헌,권나윤,김예람,최숙,김성희,노열,Baek, Jiyeon,Jo, Yeonu,Lee, Jeongheon,Kwon, Nayoon,Kim, Yeram,Choi, Suk,Kim, Sunghee,Roh, Yul 대한자원환경지질학회 2016 자원환경지질 Vol.49 No.1
이 연구는 사문석군 광물을 산 처리하고, 용출액을 pH 조절 하여 사문석군 광물로부터 규소와 철산화물 회수와 광물탄산화에 대해 연구하고자 하였다. 연구에 사용된 암석시료는 홍성 구항면에서 채취한 사문암으로 안티고라이트와 자철석로 구성되며, $SiO_2$(45.3 wt.%), MgO(41.3 wt.%), $Fe_2O_3$(12.2 wt.%)의 화학조성을 보였다. 자원회수실험은 $75{\mu}m$ 이하의 크기로 분쇄한 사문암을 1 M의 염산, 황산, 질산으로 각각 용해시켜 잔류물을 추출(1 단계)하였고, 남은 용출액에 $NH_4OH$를 추가하여 pH=8.6까지 상승시켜 형성된 붉은색 침전물을 회수(2 단계)하였다. 광물탄산화 실험은 침전물이 제거된 상층액에 $CO_2$를 주입한 후, pH=9.5까지 상승시켜 형성된 백색의 침전물을 회수(3 단계)하였다. 각 단계에서 회수된 잔류물과 침전물의 광물학적 특성을 확인하기 위해 XRD, TEM-EDS 분석을 실시했고, 용출액과 침전물이 제거된 상층액에 함유된 원소(Si, Mg, Fe)의 농도 변화는 ICP-AES 분석을 통해 확인했다. 용출된 금속은 Si, Fe, Mg이었다. 안티고라이트는 산과 반응한 후에도 판상을 유지하나 비정질실리카로 변했다(1 단계). pH=8.6에서 회수된 침전물은 Fe, Si, O로 구성된 비정질광물로, 2~10 nm 크기의 구형 나노물질이었다(2 단계). 마지막으로 $CO_2$를 주입한 후, pH=9.5에서 회수된 침전물은 nesquehonite[$Mg(HCO_3)(OH){\cdot}2(H_2O)$]와 lansfordite[$MgCO_3{\cdot}H_2O$]로 $1{\sim}6{\mu}m$ 크기를 가진 주상의 결정질광물이었다(3 단계). 따라서 산 처리된 사문석군 광물에서 나노물질의 실리카(잔류물)과 철산화물(침전물)을 회수가능하며, $CO_2$ 반응과 pH 조절을 이용하여 탄산염광물을 형성하였다. 회수된 실리카와 철산화물은 다른 물질로 합성하는 전구체로 유용하게 이용될 수 있으며, 이산화탄소를 이용한 광물탄산화 반응은 대기 중 이산화탄소 고정에 응용될 수 있을 것으로 기대된다. The objectives of this study were to recover silica and iron oxides and $CO_2$ sequestration using serpentine via various acid dissolution and pH swing processes. Serpentine collected from Guhang-myeon in S. Korea were mainly composed of antigorite and magnetite consisting of $SiO_2$ (45.3 wt.%), MgO (41.3 wt.%), $Fe_2O_3$ (12.2 wt.%). Serpentine pulverized ($${\leq_-}75{\mu}m$$) and then dissolved in 3 different acids, HCl, $H_2SO_4$, $HNO_3$. Residues treated with acidic solution were recovered from the solution (step 1). And then the residual solution containing dissolved serpentine was titrated using $NH_4OH$. And pH of the solution increased up to pH=8.6 to obtain reddish precipitates (step 2). After recovery of the precipitates, the residual solution reacted with $CO_2$ and then pH increased up to pH=9.5 to precipitate white materials (step 3). The mineralogical characteristics of the original sample and harvested precipitates were examined by XRD, and TEM-EDS analyses. ICP-AES analysis was also used to investigate solution chemistry. The dissolved ions were Mg, Si, and Fe. The antigorite became noncrystralline silica after acid treatment (step 1). The precipitate at pH=8.6 was mainly amorphous iron oxide, of which size ranged from 2 to 10 nm and mainly consisting of Fe, O, and Si (step 2). At pH=9.5, nesquehonite [$Mg(HCO_3)(OH){\cdot}2(H_2O)$] and lasfordite [$MgCO_3{\cdot}H_2O$] were formed after reaction with $CO_2$ (step 3). The size of carbonated minerals was ranged from 1 to $6{\mu}m$. These results indicated that the acid treatment of serpentine and pH swing processes for the serpentine can be used for synthesis of other materials such as silica, iron oxides and magnesium carbonate. Also, This process may be useful for the precursor synthesis and $CO_2$ sequestration via mineral carbonation.
히스토그램 평활화 전처리 기반 단순 선형 반복적 군집화를 이용한 슈퍼픽셀 영상 분할
백지연(Jiyeon Baek),임창훈(Changhoon Yim) 대한전자공학회 2018 대한전자공학회 학술대회 Vol.2018 No.6
Superpixel segmentation means dividing an image into many fragments which have similar property. In this paper, we propose a superpixel segmentation method using simple linear iterative clustering (SLIC) with contrast limited adaptive histogram equalization. This method uses histogram equalization as a pre-processing step for clustering. Simulation results show that the proposed method generates superpixels which have more concise boundary coherence compared with the existing SLIC method.
EFL 대학생의 영어 학습동기에 따른 독해전략 사용에 관한 분석
백지연(Jiyeon Baek) 한국중원언어학회 2018 언어학연구 Vol.0 No.46
The main purpose of this study was to investigate the use of reading strategies among EFL college students based on their English learning motivation. In order to accomplish this research purpose, the following research questions were constructed: 1) What are the types and characteristics of EFL college students’ English learning motivation? 2) What types of reading strategies do EFL college students use? 3) How do EFL college students’ reading strategy use differ depending on their English learning motivation? Forty six students from English reading classes participated in this study. Data sources were mainly from the questionnaire, and it was comprised of two sections: English learning motivation and reading strategies. This study also employed pre- and post-test TOEIC scores to assess the participants’ reading proficiency. The SPSS statistics was used for data analysis. The findings of the data analysis indicated that there was a significant correlation between students’ intrinsic motivation and global reading strategies, as well as among extrinsic motivation, global reading strategies and personal reading strategies. Lastly, instructional implications for the classroom and suggestions for further study were also discussed.
의사소통능력 향상을 위한 과업 중심 교수법의 효율적인 활용방안 연구
백지연(Jiyeon Baek) 한국중원언어학회 2017 언어학연구 Vol.0 No.42
The purpose of this study was twofold: 1) to investigate how native English-speaking instructors would apply task-based language teaching (TBLT) methods in their classrooms and 2) to explore their students’ levels of class satisfaction with the teaching methods. Nine native English-speaking instructors and 102 English major students participated in this study. To collect information about their classroom activities, this study conducted a pre-interview with the instructors. With the students, this study further conducted a survey and the focus group interview to investigate their levels of class satisfaction. According to the data analysis, the instructors would use pair and group activities and help the participants perform L2 learning activities by moving around the classroom. Those activities had a positive influence on the students’ class satisfaction. Also, the TBLT method seemed to have helped students increase classroom interaction and have a better relationship with their teachers and peers. Finally, the students’ academic levels seemed to have affected their levels of satisfaction about the application of TBLT in class. Additionally, instructional implications for L2 education and suggestions for further research were discussed.
영화감상을 활용한 문학교육 사례 연구 : 「나를 보내지 마」를 중심으로
백지연(Jiyeon Baek) 한국영미문학교육학회 2018 영미문학교육 Vol.22 No.2
The purpose of this study is to assist students in identifying detailed similarities and differences in the topic and structure of the same scenes in both novel and movie through guiding them in focusing on analyzing the same scenes between the two media categories. As a result, students will gain the ability to understand the genre features as well as the independent and discriminatory values of the novel and movie. Utilizing this focus, the teaching and learning model introduced in this study, which consists of students reading the novel after watching the movie, guides students in comparing and analyzing the similarities and differences of the subject matter and dialogue between the two media categories through narrative and storytelling, and this makes the reading and movie appreciation become more meaningful. This educational model has the following pedagogical implications. First, students can identify the similarities and differences between the visual language and written language more meaningfully by reading the novel after watching the movie. Second, in literary education using the movie, students can easily understand the emotions in drama characters through narrative. Lastly, students can understand and analyze the novel more intensively by discussing the similarities and differences of the dialogue between the two media categories. Based on these pedagogical implications, this study also introduces a 15-week lesson plan.