LiCoO₂의 합성 공정변수에 따른 리튬이차전지 정극의 전기화학적 특성 연구

이철태,오치훈,엄의흠,송연호 조선대학교 생산기술연구소 2003 生産技術硏究 Vol.25 No.2

리튬이차전지용 정극활물질 LiCoO₂를 소성법 을 이용하여 합성공정변수를 달리하여 합성하고 합성공정변수가 이들의 물리화학적인 재료특성 및 전기화학적인 특성에 미치는 영향을 조사하였다. 출발 물질로 LiOH · H₂O와 Co₃O₄를 사용하였으며, 750℃, 6시간 이상의 조건에서 결정의 LiCoO₂가 합성되기 시작하였으며, 반응온도가 높아지고 반응시간이 길어질수록 LiCoO₂의 결정성이 증가하였다. 여러 합성 조건 중 가장 우수한 전기화학적 특성을 보이는 조건은 반응옹도 750℃ 반응시간 24시간이었다. 이 조건에서 합성한 LiCoO₂로 Li/1M LiCIO₄ in PC + DME/LiCoO₂의 cell을 구성한 후 0.25mAh/㎠며의 전류밀도로 충 · 방전 하였을 경우 초기 방전 용량은 130mAh/g이였으며, 10cycle 후 방전 용량은 130mA h/g에서 109mAh/g으로 16%의 용량감소가 일어났다. LiCoO₂, the active material of positive electrode in lithium secondary battery, was synthesized by calcination with LiOH · H₂O and C0₃O₄. And relationships between synthesis condition and physical and electrochemical characteristics of LiCoO2 were investigated. Synthesis condition of 750℃, 6hr, LiCoO₄ crystal began to be formed, and the crystallinity of LiCoO₂ increased with reaction temperature and reaction time. LiCoO₂ synthesized by calcination at 750℃ during 24hr showed best electrochemical characteristics. The initial discharge capacity of LiCoO₂ synthesized under this condition was 130mAh/g, and after 10 cycles, the discharge capacity decreased to 109mAh/g.

<人道行>과 조황의 삶과 의식

조태흠(Cho, Tae-Heum) 한국문학회 2009 韓國文學論叢 Vol.52 No.-

본고는 문학 작품은 작가의 세계관의 반영물일 뿐만 아니라, 작가 자신의 독특한 삶에 대한 체험 방식이기도 하다는 인식 아래 <인도행>의 의미를 조황의 삶과 의식과 관련지어 파악하고, 이를 바탕으로 조황의 시조에 대한 인식과 그 창작 의도를 규명하여 조황과 그의 문학을 이해하는 기초를 마련하고자 하였다. 본고에서는 조황의 <인도행>의 구조를 파악하고, 그 내용은 유학의 근본목적인 ‘수기치인’을 노래하고 있음을 밝혔다. 아울러 그 내용의 핵심인 ‘광견재억’의 의미를 조황의 삶이나 의식과 관련지어 해명하였다. 또 조황은 시조를 ‘도’를 표현하는 문학으로 인식하였기 때문에 그의 시조는 유교의 근본이나 유교적 이념 그리고 유교적 삶의 실천 등을 주요 내용으로 할 수밖에 없음을 밝혔다. 조황은 자신의 시조를 통하여 그가 어떤 사람인지를 후세에 전하고자 하였다. 따라서 그는 시조 창작을 통하여 자신이 평생 걸어온 학문의 길과 유교의 근본적인 가르침, 그리고 자신이 행한 유교적 삶의 실천 등을 성찰하고 확인하는 것을 일차적 목표로 삼고, 다음으로는 이러한 자신의 학문과 삶을 자식이 본받도록 하는 것이며, 마지막으로는 이러한 자신의 삶이 시조를 통하여 후세에 전해지기를 바란 것이라 파악하였다. This study was designed to examine the meaning of a poem, Indohaeng(人道行), in terms of the life of its poet, Cho, Hwang, from the perspective that a literary work is the reflection of the writer's view of the world as well as his or her unique way of experience. On the basis of the examination, this study aimed to establish the foundation of full appreciation of Cho, Hwang and his works by identifying his perspective on Sijho(時調), which was a classical poetic genre with a unique scheme, and his purpose of creating the poem. The scheme of In Do Haeng was identified, and it was ascertained that Indohaeng was a poem about Sugichiin(修己治人 : meaning that one should mange the world only after cultivating their own mind), which is the primary goal of Confucianism. At the same time, the meaning of Gwanggyeonjaeueok(狂狷裁抑 : a man of great ambition without their behavior living up to the ambition), which is the gist of the poem, was elucidated with respect to the life of Cho, Hwang. From his perspective that Sijo was literature to represent Do(道 : referring to morality), the theme of Cho, Hwang's Sijo was oriented toward the principles and doctrines of Confucianism and his life as a staunch confucianist. Due to his longing to pass on his poetic legacy to his descendants, the primary purpose of Cho, Hwang's Sijo was to reflect and identify his lifetime scholarly journey, the fundamental teachings of Confucian, and his practice of confucian ethics. Secondarily, his poem was identified to imply that the poet would wish his children to follow his ways of learning and life as an example. Lastly, this study suggested that he had expected his life to be appreciated by the descendants through his poetry.

A Dynamic Experimental Model Simulating Serum Antibiotic Concentration

Cho, Soon Heum,Chung, Sun Sik 全南大醫大 1983 전남의대학술지 Vol.20 No.3

Exploring online students’ self-regulated learning with self-reported surveys and log files: a data mining approach

Cho, Moon-Heum,Yoo, Jin Soung Taylor and Francis 2017 Interactive learning environments Vol.25 No.8

Fast terahertz reflection tomography using block-based compressed sensing.

Cho, Sang-Heum,Lee, Sang-Hun,Nam-Gung, Chan,Oh, Seoung-Jun,Son, Joo-Hiuk,Park, Hochong,Ahn, Chang-Beom Optical Society of America 2011 Optics express Vol.19 No.17

<P>In this paper, a new fast terahertz reflection tomography is proposed using block-based compressed sensing. Since measuring the time-domain signal on two-dimensional grid requires excessive time, reducing measurement time is highly demanding in terahertz tomography. The proposed technique directly reduces the number of sampling points in the spatial domain without modulation or transformation of the signal. Compressed sensing in spatial domain suggests a block-based reconstruction, which substantially reduces computational time without degrading the image quality. An overlap-average method is proposed to remove the block artifact in the block-based compressed sensing. Fast terahertz reflection tomography using the block-based compressed sensing is demonstrated with an integrated circuit and parched anchovy as examples. (C) 2011 Optical Society of America</P>

Effect of Residual Lithium Compounds on Layer Ni-Rich Li[Ni_0.7Mn_0.3]O₂

Cho, Dae-Hyun,Jo, Chang-Heum,Cho, Woosuk,Kim, Young-Jun,Yashiro, Hitoshi,Sun, Yang-Kook,Myung, Seung-Taek The Electrochemical Society 2014 Journal of the Electrochemical Society Vol.161 No.6

<P>In order to confirm reasons that deteriorate cathode performances, Ni-rich Li[Ni0.7Mn0.3]O-2 is modified by lithium isopropoxide to artificially provide lithium excess environment by forming Li2O on the surface of active materials. X-ray diffraction patterns indicate that the lithium oxide coating does not affect structural change comparing to the bare material. Scanning electron microscopy and transmission electron microscopy data show the presence of coating layers on the surface of Li[Ni0.7Mn0.3]O-2. Electrochemical tests demonstrate that the Li2O-coated Li[Ni0.7Mn0.3]O-2 exhibits a greater irreversible capacity with a small capacity because of the presence of insulating layers composed of lithium compounds on the active materials since these layers delay facile Li+ diffusion. Also, the Li2O layer forms byproducts such as Li2CO3, LiOH, and LiF, as are proved by X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry. The presence of residual lithium tends to bond with hydrocarbons induced from decomposition of electrolytic salt during electrochemical reactions. And the reaction, accelerated by the decomposition of electrolytic salt that produces the byproducts, causes the formation of passive layers on the surface of active material. As a result, the new layers consequently impede diffusion of lithium ions that deteriorate electrochemical properties. (C) 2014 The Electrochemical Society.</P>

南坡 時調에 나타난 ‘自然’의 의미

조태흠(Cho, Tae Heum) 부산대학교 인문학연구소 1991 코기토 Vol.39 No.-

〈酒老園擊壤歌〉의 구조와 의미

조태흠(Cho Tae-Heum) 한국문학회 2007 韓國文學論叢 Vol.46 No.-

  This paper aims to investigate the structure and overall meaning of the work〈Jurowongyeogyangga〉by Chohwang. We summarize the following based on the discussion so far.<BR>  1. The prologue of〈Jurowongyeogyangga〉consists of three equally meaningful paragraphs. We showed that the first paragraph sings of the speaker"s determination to live in retirement as a part of nature, and that the second paragraph expands the motif of choosing that retirement, while the last paragraph expounds on the speaker"s life inside nature.<BR>  2. The 4 seasons of one year is mirrored in the progress of this work. This verse (sijo) has 4 seasonal verse structures that poetical imagination develops according to the sequential progress of the 4 seasons in the following order; the spring, the summer, the fall, the winter.<BR>  3.〈Jurowongyeogyangga〉is mainly about living a life of retirement as an integral part of nature and this life of retirement which the author describes is an ideal life in his conception. It does not concretely embody his life, but rather follows in the steps of traditional literary expression, because his life in this work is far removed from the author"s actual life.<BR>  4. In the work〈Jurowongyeogyangga〉, the author repeatedly sings in every season of hopes to enter government office. Therefore, this work is a song which awaits the time of achieving government office by living in retirement rather than singing of a life of simple retirement.<BR>  5. In the work〈Jurowongyeogyangga〉, the direct expression of affection and admiration towards the peasantry can be seen. This kind of work expresses the overarching morality of poverty and lowliness in the eyes of society and Chohwang himself had deep comprehension of the farmer"s life and also used metaphors connecting the farmer"s work to that of illustrious officials.

대규모 시설원예의 냉난방 에너지 절감을 위한 바이오매스 이용 가능성에 관한 연구

조정흠(Cho, Jeong-Heum),남유진(Nam, Yu Jin) 대한건축학회 2014 대한건축학회 학술발표대회 논문집 Vol.34 No.2

안민영 애정시조의 성격과 그 이해의 시각

조태흠(Cho, Tae-Heum) 부산대학교 한국민족문화연구소 2015 한국민족문화 Vol.54 No.-

본고에서는 안민영의 애정시조를 대상으로 애정의 진정성과 정서의 일반화 양상을 고찰하고, 애정시조를 이해하기 위한 시각을 제시하였다. 주요한 논의 사항은 다음과 같다. 첫째, 안민영의 애정시조는 만남, 이별, 그리움을 노래하고 있는데 그 작품은 모두 28수이며, 그 애정대상은 안민영과 각별한 관계에 있었던 몇몇 기녀들에 집중되어 나타난다. 둘째, 안민영의 애정시조에서 애정의 진정성은 작품의 ‘재현적 진실’이 아니라, 작가의 감정 표현의 ‘성실성’에 평가 기준을 두어야 한다. 안민영은 자신의 진실한 감정에 바탕을 두고 애정시조를 창작하였으므로 그의 작품에 표현된 애정에는 진정성이 있다고 보아야 한다. 셋째, 안민영 애정시조의 화자는 특정한 인물이 아니라 누구나 자기 자신이 화자라고 생각할 수 있는 비특정화된 인물이며, 작품 속 애정대상도 그의 실제 애정대상이었던 특정한 기녀가 아니라 비특정화된 인물이다. 넷째, 안민영은 화자와 그 애정대상을 비특정화하는 방법을 통하여, 불특정 다수가 화자의 감정이나 작품 속의 상황을 자신의 감정이나 상황으로 받아들일 수 있도록 정서를 일반화하고 있음을 밝혔다. 다섯째, 안민영의 애정시조에서 작품과 작품 후기를 일대일 대응관계로 파악하여 작품과 후기의 내용이 일치하는 것으로 이해할 것이 아니라, 후기는 작품을 창작하게 된 동기나 배경 정도로 보아야 하며, 작가 안민영과 화자와의 관계 역시 작품 속 화자를 작가와 ‘자전적으로 동일시’할 것이 아니라, ‘상상적으로 동일시’해야 할 것이다. 마지막으로 화자와 애정대상의 비특정화를 통한 정서의 일반화라는 애정시조의 성격은 안민영이 창작의 과정에서 작품이 실제로 연행되거나 연행될 것을 염두에 두고 창작한 결과이기 때문에 그의 애정시조는 연행과 관련지어 이해해야 할 것이다. This research seeks to investigate Min-Young An"s love sijo works, especially, in terms of the authenticity of love and the aspect of generalized affections shown in the works. In addition, it aims to provide a new perspective from which the reading of his works can lead to a better understanding. Some major points discussed in the argumentation can be stated as follows. Firstly, concerning Min-Young An"s love sijo works, they particularly focus on certain specific topics like encountering, parting, and missing and, in the total number of 28 sijo poems, the main objects of his affection are limited to several female individuals who were in an intimate relationship with Min-Young An himself while working as a ginyeo (妓女). Secondly, the authenticity of the feelings of affection should be evaluated not by the criterion of "representational truth" but in terms of the "truthfulness" of the author"s affections. Therefore, knowing that Min-Young An"s love sijos are characterized by the explicit description of how An himself genuinely feels about some ginyeo figures, it should be argued that his love feelings in the sijo works need to be understood as having authenticity. Thirdly, throughout his love sijos, the speakers should be viewed as an unspecified figure rather than as a specific individual. In the same sense, it is proposed that the objects of the affection present in the works must be some unspecified figures, not those particular ginyeos whom he was adoring. Fourthly, it is found that those love sijos are composed in such a way that the unspecification of the speakers and the objects of affection can increase acceptability and assimilation in many non-particular individuals" responses. It is self-evident that such a device would give birth to the generalization of affections, which helps evoke self-identification in the respective readers" reading of certain feelings and circumstances present in the poems. Fifthly, for a good understanding, An"s sijo works should not be taken to be related to the afterwords of those poems-as if there were a one-to-one correspondence between the two. The afterwords instead need to be viewed as motivating factors or background information. In a similar vein, the relationship between Min-Young An, the author himself, and the speakers in his works is proposed to be understood by means of "imagination-based identification", not on the basis of "autobiography-related identification". Finally, the main feature of those love sijo works-which is the generalization of the affections made possible by means of the unspecification of the speakers as well as that of the objects of love feelings-results from Min-Young An"s purposeful composition to have conducted for a possible or actual performance plan. For this reason, it is important to view the very feature as being related to each poem"s performativity as a critical factor.