3D flexible Si based-composite (Si@Si₃N₄)/CNF electrode with enhanced cyclability and high rate capability for lithium-ion batteries

Kim, Si-Jin,Kim, Min-Cheol,Han, Sang-Beom,Lee, Gyu-Ho,Choe, Hui-Seon,Kwak, Da-Hee,Choi, Sun-Yong,Son, Byung-Goo,Shin, Myoung-Sun,Park, Kyung-Won Elsevier 2016 Nano energy Vol.27 No.-

<P><B>Abstract</B></P> <P>Despite extremely high capacity of Si-based anodes in lithium-ion batteries (LIB), Si-based materials have shown a structural collapse caused by a volumetric expansion/contraction during the cycling process. The conventional electrode structure, which consists of active materials, a current collector, a conducting agent, and a binder, actually showed a low loading of active material due to the other heavy components. In this study, we prepared a 3D flexible Si-composite electrode consisting of core (Si)-shell (Si<SUB>3</SUB>N<SUB>4</SUB>) NPs (Si@Si<SUB>3</SUB>N<SUB>4</SUB>) and carbon nanofibers (denoted as Si-composite/CNF). The Si-composite/CNF was directly utilized as an anode in the absence of the other components was electrochemically evaluated using a coin-type cell. The Si-composite/CNF showed a high capacity of 665mAhg<SUP>−1</SUP> at a fairly high current density of 10Ag<SUP>−1</SUP> and an extremely low capacity loss for 2000 cycles.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We prepared Si-composite/CNF exhibits a 3D flexible Si-composite electrode. </LI> <LI> The electrode consists of core (Si)-shell (Si<SUB>3</SUB>N<SUB>4</SUB>) NPs (Si@Si<SUB>3</SUB>N<SUB>4</SUB>) and carbon nanofibers. </LI> <LI> The Si-composite/CNF was directly utilized as an anode. </LI> <LI> Si-composite /CNF exhibited high specific capacity and improved high rate cycling performance. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

원거리 플라즈마 화학증착법으로 증착된 이산화규소박막의 물성

박영배,강진규,이시우,Park, Yeong-Bae,Gang, Jin-Gyu,Lee, Si-U 한국재료학회 1995 한국재료학회지 Vol.5 No.6

원거리 플라즈마 화학증착법을 이용하여 저온에서 이산화규소박막을 제조하였다. 본 연구 에서는 공정변수인 기판의 온도, 반응기체의 조성 및 분압과 플라즈마 전력에 따른 산화막의 재료적인 물성을 평가하였다. XPS결과에서 산화막은 양론비(O/Si=2)보다 약간 적어 실리콘이 많이 함유된 막으로 나타났다. 이 경우 굴절율과 ESR분석에 의해 미결합된 실리콘의 양이 증가함을 알 수 있었다. SIMS분석에 의해 미량의 질소성분이 계면에 존재하는 것과 실리콘 미결함을 관찰하였다. FT-IR로부터 막내 수소량을 정량화하였으며 결합각 분포는 20$0^{\circ}C$이상에서 열산화막과 비슷한 값을 얻었다. 하지만 열산화막에 비해 높은 식각율을 보여 계면 스트레스에 의해 막내의 결합력이 약해진 것으로 생각된다. Silicon oxide thin films were deposited by remote plasma chemical vapor deposition (RPCYD). The effect of the operating variables, such as plasma power, deposition temperature and partial pressure of reactant on the material Properties of the silicon oxide film was investigated. By XPS, it was found out that the film was suboxide (O/Si<2) and small amount of nitrogen due to the plasma excitation was accumulated at the Si/SiO$_2$interface. The amount of dangling bonds at the Si/SiO$_2$interfaces were measured by ESR and the concentration of hydrogen bond was obtained by SIMS and FT-IR. The bond angle distribution(d$\theta$/$\theta$) was shown to be similiar to thermal oxide above 20$0^{\circ}C$ but the etch rate was higher than that of the thermal oxides due to the structural difference and the stress between silicon substrate and silicon oxide film.

파킨슨병의 음성분석학적 특징

이규한,박시복,이상건,이강목,김승현 大韓再活醫學會 1998 Annals of Rehabilitation Medicine Vol.22 No.3

정보화 사회를 위한 구성주의적 수학 교수 ·학습을 위한 수업모델 적용에 관한 연구

유시규,최수택 東國大學校 敎育硏究院 1997 교육문제연구 Vol.12 No.-

In the traditional mathematics education, knowledge is considered to transmit from a teacher to students, but in the new student-oriented mathematics education, they think knowledge is attained by the students themselves with the help of a teacher. In this respect, as the background theory of mathematics education, constructivism that claims knowledge is acquired through students' in dependent study, gets influential. In this study, 1'd like to propose constructivism as the most effective mathematics teaching and teaming methodology through studying the theoretical background of constructivism and its practical applications in the mathematics education. In the classroom I applied the constructivist's teaching method to the students and so let them have positive attitude in the study and induce the students to a creative participation. The constructive approach to the mathematics problem solving helped the students realize their abilities. To apply the constructive methodology on the spot -in other word, in the classroom application- the teacher should develop teaching aids and participate in the research activities actively To shift from the teacher-oriented teaching and teaming methodology to the student-oriented is not an easy task. And the general tendency of Korean education changes slowly. But the constructivists' experiments are meaningful from the standpoint of future-oriented education.

수학교육에 있어서 지레 짐작의 위치부여

柳時珪 敎育問題硏究所 東國大學校 1995 교육문제연구 Vol.10 No.-

Even though it is good in the achievement condition of the memory reproducing type questions as like the formal calculations or the applications of the formulas, it is not in the questions that are requiring problem student's own judgment. That's why only formulas and skills to solve them are being conveyed to the students tin our classrooms. current school education's goal is to provide the students the basis of their lifelong study by emphasizing on the self-motivation to learn something for themselves and on bringing on their abilities to voluntarily react to the social changes. The daily practice to get knowledge and skill makes students face new problems. That means they are required to handle new problems on the daily base. So far the study of the mathematics education has a tendency to place a strong stress on its theory itself. but now the practical studies about it are prevailing on the reflection of it. In developing the open-ended approach that enhances the problem solving abilities, it is reasonable to think that whatever dealt in the classroom should be based on the joint thinking and the joint work of the teachers and the students, but teacher tends to rush into a hasty conclusion and fail to induce appropriate outcomes. It is, however, one of the most important thing to let the students be interested in and is involved in the process, considering the difference of every each one of the individuals' problem solving abilities or their various thinking patterns and thking care of when or how to give them hints that could lead them to the right conclusion. The thinking process to the answer, that is, how to place the step of conclusion from posing a question to arriving at the solution is more important than any other things. And also it is thought that a lot of practical studies as well as a lot of methods to evaluate the process of the teaching and learning theory are needed accordingly.

GIS를 이용한 산불발생위험지역 구분

이시영,안상현,원명수,이명보,임태규,신영철 한국지리정보학회 2004 한국지리정보학회지 Vol.7 No.2

산불로 인한 재해를 미연에 방지하고 피해를 저감하기 위해서는 산불발생위험지역을 사전에 파악하여 예방대책을 세울 필요가 있다. 따라서 본 연구에서는 산불발생인자에 따른 산불발생위험지역을 구분하고자 겸상북도 의성군에서 발생한 산불피해지역에 대하여 임상, 지형 등에 대하여 조사하였다. 조사된 요인들 간 독립성 유무를 상관분석을 이용하여 산불발생과 관련 있는 7개의 주제도를 선정하였으며, 선정된 주제도를 조건부확률과 지리정보시스템을 이용하여 산불발생확률을 계산하였다. 계산된 산불발생확률을 20개 등급으로 지수화하여 산불발생위험지역을 구분하였다. In order to decrease the area damaged by forest fires and to prevent the occurrence of forest fires, we are making an effort to improve prevention measures for forest fires. The objective of this study is to classify hazard regions where forest fires occur based on the factors that contribute to the occurrence of forest fires. Forest fire sites in the Uiseong-gun, Gyeongsangbuk-do were surveyed according to the factors of forest type and topographic characteristics where the forest fires occurred. We used a correlation analysis to determine the forest fire occurrence factors and a conditional probability analysis and GIS to determine a forest fire danger index. The resulting forest fire danger index was used in the classification of forest fire occurrence risk regions.

烏貝散이 흰쥐 胃의 Gastrin, Histamine, Somatostatin 면역반응세포에 미치는 영향

이시섭,나현욱,고병문,이광규,이창현 대한동의병리학회 2001 동의생리병리학회지 Vol.15 No.5

To investigate the elects on the administration of Opae-san in rats. Opae-san (500mg/day) and omeprazole(10mg/day) were administration with stomach tube for 4 weeks and 8 weeks. This experiment were investigated numerical change of immunoreactive cells of gastric, histamine and somatostatin in rat stomach mucosa by the immunohistochemical method. The results were as follows : 1. In Opae-san administration group for 4 weeks, the number of gastric immunoreactive cells were increased in one and a half times than that of control group. In omeprazole administration group for 4 weeks, the number of gastric immunoreactive cells were increased in four times than that of control group. In Opae-san administration group for 8 weeks, the number of gastric immunoreactive cells were increased four times than that of control group. In omeprazole administration group for 8 weeks, the number of gastrin immunoreactive cells were increased in six times than that of control group. 2. In Opae-san administration group for 4 weeks, the number of histamine immunoreactive cells were increased in two times than that of control group. In omeprazole administration group for 4 weeks, the number of histamine immunoreactive cells were increased in six times than that of control group. In Opae-san administration group for 8 weeks, the number of histamine immunoreactive cells were increased three times than that of control group. In omeprazole administration group for 8 week, the number of histamine immunoreactive cells were increased in seven times than that of control group. These results suggest that Opae-san extracts inhibit the secretion of gastric acid and this extract use to therapeutic herb of gastric disorders related to the hyperacidity and gastric ulcer.

토안에서 금판 삽입술의 효과

최시환,박영규,박우찬 충남대학교 의과대학 지역사회의학연구소 1993 충남의대잡지 Vol.20 No.1

Lagophthalmos can result in serious keratopathy because of corneal exposure and inadequate lacrimation. Four patients underwent gold plate insertion to rehabilitate paralysis of the eyelid caused by facial nerve palsy. Gold plate insertion resulted in exellent eyelid closure, protection, and cosmesis. There were no infections or extrusions. Lagophthalmos and exposure keratitis were resolved or were significantly improved in these patients. In selected patients this technique reestablishes a voluntary blink and provides corneal protection without the limitation of tarsorrhaphy. Gold plate insertion has become the procedure of choice for eyelid rehabilitation.

CaWO4증감지의 X선 조사에 따른 결함증가와 화질에 미치는 영향

김창규 ; 홍시영 김천대학교 2003 김천대학교 논문집 Vol.24 No.-

This paper analyzed the variation of characteristic image by defect of increase in intensifying screens. When the intensifying screens were exposed by X-ray, the defect crys- tals are increased. SEM shows the differences between them. It is shown that the defect characteristic curve of the intensifying screen between an artificial defect one and normal one was different. The Image Quality(I.Q) values and the resolving power values (LP/mm) with an artificial defect screen are decreased in comparison with the normal screen.

관상동맥 질환에서 SDF-1α의 농도

김보영,박용규,박형서,노상필,정승현,이유선,이정우,이재환,최시완,정진옥,성인환 충남대학교 의과대학 의학연구소 2003 충남의대잡지 Vol.30 No.1

Atherosclerosis is now viewed as an inflammatory disease of the vascular system. Expression of several chemokines, including monocyte chemoattractant protein(MCP)-1, MCP-4, RANTES(regulated on activation normal T-cell expressed and secreted), and interleukin-8(IL-8) are increased in human atherosclerotic plaques compared with normal vessels. They are involved in the pathogenesis of atherosclerosis and plaque rupture by activating and directing leukocytes into the atherosclerotic lesions. However, some are involved in homeostatic functions such as normal leukocyte traffic and growth regulation. SDF-la is a multi-functional cytokine that is involved in myelogenesis, hematopoiesis, angiogenesis and injured gastric mucosal regeneration in the gastric ulcer patient. SDF-la is recently shown to be highly expressed in atherosclerotic plaques and a potent platelet agonist. At least in high concentrations, SDF-la may mediate antiinflammatory and matrix stabilizing effects in unstable angina. Many studies are going on to know the function of SDF-la in coronary artery diseases. I investigated the difference of the plasma level of SDF-la between control group and coronary artery disease group. Total 75 subjects were enrolled. The diagnosis of coronary artery disease was confirmed in all patients by coronary angiography. Control subjects in this study were confirmed normal by coronary angiography. Clinical profile and risk factors were also reviewed. Control subjects in this study were 27 (M=10, F=17). Plasma for the study was collected before the angiography and centrifuged. SDF-la analysis was performed by ELISA. Plasma level of SDF-la is significantly increased in patients with stable angina(n=20) and unstable angina group(n=28) compared with healthy control group(n=27). the risk factors do not influence the plasma level of SDF-la in coronary artery diseases. In this study, plasma level of SDF-la is increased in patients with stable angina and unstable angina groups compared with healthy control group(P<0.05). the risk factors do not influence the plasma level of SDF-la in coronary artery diseases.