• Title/Summary/Keyword: Time-based

Search Result 53,263, Processing Time 0.095 seconds

Growth, Quality and Irrigation Requirements of Melon Cultivars in Hydroponic Cultivation Using Coir Substrate (코이어 배지를 이용한 멜론 수경재배 시 품종별 생육, 품질 및 급액 요구량)

  • Lim, Mi Young;Roh, Mi Young;Jeong, Ho Jeong;Choi, Gyeong Lee;Kim, So Hui;Choi, Su Hyun;Lee, Choung Keun
    • Journal of Bio-Environment Control
    • /
    • v.30 no.3
    • /
    • pp.188-195
    • /
    • 2021
  • This study was conducted to investigate the growth and quality characteristics of melon (Cucumis melo L.) cultivars and the irrigation requirements for cultivars. In our previous study in 2019, twelve melon cultivars including 'Dalgona' were examined for their cultivar characteristics under the same irrigation condition for all cultivars, and sorted into several groups based on different growth condition; for the internode length (from 0 to 20th node), leaf area, and fruit weight, 'Kingstar' belonged to the largest group, 'Worldstar' the middle group, and 'Dalgona' the smallest group. After analyzing the results of the previous experiment, 'Dalgona', 'Worldstar', 'Kingstar', and 'Rubyball' were selected as test cultivars for the growth group in 2020, and irrigated according to different irrigation levels for each cultivar. The control of the irrigation volume for each melon cultivar by monitoring the drainage rate during the cultivation periods showed that all four cultivars required a similar amount of irrigation in the 'early growth' stage where crops grew at about the same rate. From 'flowering time', however, the change in irrigation requirements showed a similar tendency for 'Worldstar' and 'Kingstar' and for 'Rubyball' and 'Dalgona' respectively. A sudden change in each irrigation volume was observed from the fruit set; 'Dalgona' began first to decline and 'Rubyball' was second, followed by 'Worldstar' and 'Kingstar'. In conclusion, the irrigation volume was the largest in 'Kingstar', followed by 'Worldstar', 'Rubyball', and 'Dalgona' in the same order as the growing amount of plant length, leaf area, and fruit weight. Therefore, it is necessary to control exactly the irrigation volume by reflecting the unique growth characteristics of each cultivar for the production of high-quality fruit in melon hydroponics, and especially to use great care when different cultivars are cultivated together.

E. Husserl's Phenomenological Ego (E. 후설의 현상학적 자아)

  • Bai, Woo-soon
    • Journal of Korean Philosophical Society
    • /
    • v.146
    • /
    • pp.49-77
    • /
    • 2018
  • This essay examines the ego (I-Subject) problem in Husserl's phenomenology and consists of four parts, as follows. Section I describes the meaning of this research on ego and some important points to note in relation to this study. Section II discusses two aspects of the problem of pure ego, which appears as an ego-problem for the first time. The first aspect is the two opposing positions that Husserl himself took regarding pure ego. Husserl initially rejected pure ego as an object of research in Logische Untersuchungen I (1901) however, he withdrew this position in Logische Untersuchungen II (1913). The second aspect is the content of pure ego that Husserl explored in Ideen I (1913) after he accepted pure ego as a phenomenological problem. The theme of section III is the "theory of three egos" which appeared in Ideen II (1912, 1952). Here, two issues have been noted, one of which is the methodological basis for enabling this theory: the phenomenological "attitude change" (Einstellungsaenderung) and the "Underlying" (Fundierung). The other is the explanation of the content of the three egos: the "physical ego", "personal ego" and the "pure ego". Section IV concerns two themes of the "monadic ego" that appeared in the Cartesianische Meditationen (1931). The first theme is the theoretical premise for the establishment of the monadic ego. In conjunction with this theme, phenomenological-psychological reduction was used as a new method to open up new problem horizons. The second theme brings up the content of the monadic ego, the essence of which can be summarized as follows. 1) This ego is based on a pluralistic and independent ego-concept in which each ego is equal to its own self. 2) It must be asked whether each of the monadic egos is different from one another. 3) The "other" of a certain transcendental ego is not the ego-other relationship but ego-another ego (alter-ego). 4) This phenomenological monadic ego can mutually communicate with alter-egos through empathy, unlike Leibniz's metaphysical monads.

Paragon of people circling the pagoda of Woljeongsa Temple and performance of its cultural inheritance (월정사 탑돌이의 전형과 공연문화)

  • Lee, Chang-sik
    • (The) Research of the performance art and culture
    • /
    • no.36
    • /
    • pp.751-781
    • /
    • 2018
  • Task of circling the pagoda of Waljeongsa(Woljeongsa Tabdori) is the major intangible cultural heritage with representativeness and historical meaning as a Buddhism culture, one of the Buddhism folk plays, which was firstly played after the liberation. Woljeongsa Tabdori holds significant designation importance in terms of Buddhism folklore heritage with Korean unique tradition and identity of Gangwon-do province. Temples are demonstrating Tabdori nationwide but Woljeongsa Tabdori is the unique case that systematically inherits the culture based on the designation of being intangible cultural heritage. That is why it is needed to focus on the cultural and internal value of Woljeongsa Tabdori. Tabdori is the integrated symbol of Buddhism respect and worship to the Buddha and pagoda. It is hard to presume the originality of Woljeongsa Tabdori: given the history of Woljeonsa temple, it lies into Goguryeo traditional play and Bokhui(Pagoda circling folk play) in Silla era. It fits into the courtesy of Circumambulating Stupa considering Moon in Goguryo mural, background of Odaesan Hwaeom thought/tripitaka and essence of Octagonal 9-story stone pagoda. At the first stage of Tabdori, Buddhist musical instruments such as Buddhism temple bell, singing bowl, cloud-shaped gong and wooden-fish. However, later, Samhyeon Yukgak has been added and then, Boyeom and Bakpaljeongjinga were singing: it could be interpreted that it was a pure Buddhist ceremony but it has become to have traditional aspect and been spread to the public. The origin of Woljeongsa Tabdori is related to the explanation of Circumambulating Stupa that experiences the glory of the ending ceremony. When a temple has a rite, the Buddhists make an offering to the Buddha. At that time, Buddhist prayer, sermon and chant are followed. After the rite, the Buddhists are circling the pagoda with the monks while praying for Buddhist charity and making their own wishes. It prays not only going after death to Nirvana of the one but also national prosperity and the welfare of the people for peaceful reign. As the temple holds bigger rites, many Buddhists gather and the Tabdori was a success. The scene of circling the pagoda and making own wishes in line with the Buddhist sermon was solemn. The idea on changes and convergence of Woljeongsa Tabdori requires strategic inheritance to promote the transmission while maintaining the paragon and purpose of designating the cultural heritage and reviving its identity. Korean Tabdori was held in Buddha's birthday in April and the mid-autumn day. Tabdori is a memorial service type Buddhist ceremony that once the monk holds the Buddhist rosary, circles the pagoda and sings the great mind and charity of the Buddha, Buddhists follow the step, lighting the lantern, circling the pagoda and praying for the gentle and easy death. Transmission education of the successor, diversified approach of the expert's advice and discourse on the revival of the origin should be reinforced in phases.

A study on recording Gut's performance history - To search on how to create a performance out of Gut - (굿공연사 기술을 위한 시고 - 굿의 공연화 방법 모색을 위한 -)

  • Kim, Hyung Kun
    • (The) Research of the performance art and culture
    • /
    • no.36
    • /
    • pp.693-724
    • /
    • 2018
  • This article was started to find a way for creating a performance out of Gut. In order to find such way, the first thing that had to be done was to organize the Gut performances that had been made until now. It was to organize the existing study on the performances and to seek a different way from it, believing that the virtue of a performance is to 'create diversity'. However, it was not easy to organize the Gut performances, which became full-scale in the 1980s, because they were never organized before. Therefore, based on my direct and indirect experience, I have organized the most important performances in chronological order. Most importantly, as the planners of the performances (can sometimes be a group or an organization instead of an individual) are the ones who make the show possible, I have noted on them with keen interest. The National Folk Art Performance Contests in Korea, Theater 'Space Sarang', The Association of Gut, Theater 'Madangsesil', Seoul Nori Madang, and National Gugak center were the center space and planning body of the Gut performances. Recording the history of Gut is a worthwhile work of its own. However, it is a substantial amount of task to be done with individual effort, and it has to be progressed as a public project in order to promote and spread its value. Therefore, this article raises the need for it. Meanwhile, as stated earlier, this article has recorded the history of Gut performances as a precondition to finding a way to create a performance out of Gut. From the experimental organization of the Gut performances history, I could find out that most of the performances had the people who did Gut as the main body and the method of the Gut performance did not significantly deviate from just reenacting the original Gut at the time of when it was performed. Therefore, I have introduced Shinmyeong, the Nori-Pae (troupe), and TheGwangdae, the Korean Traditional Performance troupe, who create Madangguk from various Gut materials. By refining the wholly complicated performance elements of the Gut, it could escape from the 'reenacting' performance to becoming a material or a metaphor for a whole new performance.

Truth of Mahāyāna Thought -The Controversy Between The Madhyamaka and The Yogācāra on Sunya and The two truth theories of Nāgārjuna (대승불교의 진리관 -용수(龍樹)의 공(空)과 이체설(二諦說)에 대한 중관학파(中觀學派)와 유지학파(唯識學派)의 논쟁을 중심으로)

  • Yun, Jong-gab
    • Journal of Korean Philosophical Society
    • /
    • v.116
    • /
    • pp.225-256
    • /
    • 2010
  • The two school $M{\bar{a}}dhyamika$ and $Yog{\bar{a}}c{\bar{a}}ra$ act as a representative of $Mah{\bar{a}}y{\bar{a}}na$ Buddhism in India. But the two school disputed with each other insisting ${\acute{s}}{\bar{u}}nyat{\bar{a}}-v{\bar{a}}da$ and $vij{\tilde{n}}aptim{\bar{a}}trav{\bar{a}}da$ separately. To introduce the disputation shortly is as follow. $N{\bar{a}}g{\bar{a}}rjuna$ explained the world and truth by two truth theories(二諦說) which carry out truth of a word and the dimension(spiritual enlightenment) which is absolute(ultimate) to it being lokasaṁvṛtisatya(世俗諦) about the truth which can be expressed verbally, and which is phenomenon-like (everyday) at paramaarthasatya(勝義諦). By the way, lokasaṁvṛtisatya and paramaarthasatya are actually distinction of the recognition which is not an ontological distinction. That is, lokasaṁvṛti(世俗) is paramaartha(勝義) as it is the time of seeing by the eyes of those who have realized. The two truth theories of $N{\bar{a}}g{\bar{a}}rjuna$ was developed logical more precisely by his successors. With an everyday language, the position of Candrakīrti(月稱) that it cannot be expressed as the position of $Bh{\bar{a}}vaviveka$(淸辨) that paramaarthasatya can be expressed logically is opposed to each other, and dissociates by $Sv{\bar{a}}tantrika$(自立論證派) and $P{\bar{a}}rsagika$(歸謬論證派). Confrontation of $Sv{\bar{a}}tantrika$ and $P{\bar{a}}rsagika$ is the dispute about the ability of s which is the highest truth to be proved logically. The $P{\bar{a}}rsaga$ of Candrakirti thinks that people exist truly, and is because it claims not existing in the world where a favorite thing is actually actual. However, $Bh{\bar{a}}vaviveka$ proved Sunyata(空性)을 positively based on the reliance to language and logic. Also the mokṣa of $M{\bar{a}}dhyamika$ is not recovery of original condition of $vij{\tilde{n}}apti$ which is pure in itself as $Yog{\bar{a}}c{\bar{a}}ra$ saying, as well as obtaining a thing which is dravya-sat as $Sarv{\bar{a}}stiv{\bar{a}}din$ saying. The mokṣa of $M{\bar{a}}dhyamika$ means a condition of liberated from karma and pains through extinction of $prapa{\tilde{n}}ca$ and discrimination by realizing the real aspect of all dharma which is said by pratītyasamutpāda, $praj{\tilde{n}}apti$, niḥsvabhāva, ${\acute{s}}{\bar{u}}nya$, $madhyam{\bar{a}}pratipad$.

The post-epic characteristics in Jan Lauwers' theatre -, and - (얀 라우어스(Jan Lauwers) 공연의 탈서사적 특징들 -<이사벨라의 방(Isabella's Room)>, <랍스터 가게(The Lobster Shop)>, <사슴의 집(Deer House)>을 중심으로-)

  • Nam, Jisoo
    • Journal of Korean Theatre Studies Association
    • /
    • no.48
    • /
    • pp.447-484
    • /
    • 2012
  • This study aims to analyze the characteristics of post-epic theatre in the Belgian theatre director Jan Lauwers' trilogy titled in "Happy Face/Sad Face": (2004), (2006) and (2008). I regard that it played a very important junction for him to create his own theatrical style compared to earlier years. From this period, Lauwers has tried to create his original plays in order to concentrate the story of our era and has showed to combine a variety of media such as dance, installation, video, singing etc. In this context, I would like to study his own theatricality from the three perspectives of dramaturgy, directing and acting largely based on Hans-Thies Lehmann's theory of post-epic theatre, who pointed out the significance of Lauwer's theatrical leading role very early. First, from the dramaturgical point of view, we need to pay attention to the theme of translunary death; where the living and the dead coexist on the stage. In fact, death is the theme that Lauwers has been struggling to research for quite long time. In his trilogy, the dead never exits the stage. The dead, who is not a representative tragic character, even meddles the things among or with the living and provide comments to people. As a consequence, it happens to reduce a dramaturgical strong tension, leads depreciation of suspense and produces humanism in a way. This approach helps to create his unique comical theatrical atmosphere even though he deals with the contemporary tragic issues such as war, horror and death. Second, from the directing point of view, it is worth to take a look at the polyphonic strategy in terms to applying various media. Among all the things, the arts of dancing and singing in chorus are actively applied in Lauwer's trilogy. The dance is used in individual and microscopic way, on the other hand, singing shows collective and is a macroscopic quality. The dance is the representing media to show Lauwer's simultaneous microscopic mise-en-scene. While main plot takes place around the center-stage, actors perform a dance around the off-centered stage. Instead of exiting from the stage during the performance, the actors would continue dance -sometimes more like movements- around the off-centered stage. This not only describes the narrative, but also shows how each character is engaged to the main plot or incident, and how they look into it as a character. Its simultaneous microscopic mise-en-scene intends to function such as: showing a variety moments of lives, amplifying some moments or incidents, revealing character's emotion, creating illusionary theatrical atmosphere and so on. Meanwhile, singing simple lyrics and tunes are an example of the media to stimulate the audiences' catharsis. As the simple melody lingers in the audiences' mind, it ends up delivering a theatrical message or theme after the performance. This message would be transferred from the singing in chorus functions as a sort of leitmotive in order to make an impression to the audience. This not only richens their emotion but also creates an illusionary effect. Third, from the acting perspective, I'd like to point out the "detachment" aesthetic which Lehmann has pointed out. The actors never go deep into the drama by consistently doing recognize a theatrical illusion. The audience happens to pay attention to their presence through the actor's deliberate gesture, business, movement, rhythm, language, dance etc. The actors are against forming closed action by speaking in various languages or by revealing deliberately stage directions or acts, and by creating expressive mise-en-scene with multiple media. As a consequent, the stage can be transformed to not a metaphoric but a metonymic place. These actions are the ultimate intention for a direct effect to the audience. So to speak, Lauwers uses the anti-illusionary theatrical method: the scenes of fantastic death, interruption of singing and dance, speaking many kinds of languages, acting in detachment-status and so on. These strategies function to make cracks in spectators' desire who has a desire to construct a linear narrative. I'd like to say that it is the numerous potentiality to let the reality penetrate though and collide the reality with a fiction. By doing so, it induces for spectators to see the reality in the fiction. As Lehmann says, "when theatre presents itself as a sketch and not as a finished painting, the spectators are given the chance to feel their own presence, to reflect on it, and to contribute to the unfinished character themselves". In this sense the spectators can perform an objective criticism on our society and world in Lauwer's theatre because there are a number of gaps and cracks in his theatrical illusion where reality can penetrate. This is also the point that we can find out the artists' responsibility in this era of our being.

A Study on Forming 'Body Schema' for Role Creating (역할 창조를 위한 '몸틀(body schema)' 형성 연구)

  • Song, Hyo-sook
    • Journal of Korean Theatre Studies Association
    • /
    • no.52
    • /
    • pp.319-357
    • /
    • 2014
  • Formation of 'body schema' is the start for actor to create role and becomes the root and the foundation of existing as a role on the stage. For this, an actor needs to form 'scheme of role' with escaping from own 'body schema.' 'Schema of role' is formed by acquiring through synthesizing daily basic actions, namely, walking, standing, sitting, hand stretching, bending, and touching. The body schema, which was made with simple and usual actions, has fundamental significance in a sense of becoming the body in which the past traces in a role are habituated while energy as a role flows. As for the process of forming body schema, an actor first needs to obtain the visualized materials like photo, magazine, picture and image available for seeing a role specifically and clearly based on what analyzed a character. An actor needs to have three-dimensional image available for always recalling it in the head during acting. To do this, image data available for fundamentally capturing routine actions along with body structure are still more useful. Next, the body schema is formed by interaction with environment. Thus, there is a need of passing through the two-time process of forming body schema. Firstly, the body schema is made on routine actions in a role as physical condition of a role in actor's own everyday life. Secondly, the body schema is made on routine actions available for moving efficiently and economically in line with the environment of performance. A theatrical stage is the temporal space of rhythm and rule different from routine space. What forms body schema immediately in the second phase without body schema in the first phase ultimately becomes what exists as actor's own body, not the body of a role. The body schema, which was formed as the second process, is what truly has identity as a role in the ontological aspect, comes to experience the oppositional force in muscle, a qualitative change in energy, and emotional agitation in the physical aspect, and experiences perception, thinking, volition, and even consciousness with the entire body in the cognitive dimension. Thus, the formation of body schema can be known to be just a method of changing even spiritual and emotional layer. Body schema cannot be made if there is no process of embodiment and habit. Embodiment and habit are not simply the repeated, empty and mechanical action in the body. But, habit itself has very important meanings for forming body schema for role creating. First, habit allows the body itself to learn and understand a meaning. Second, habit relies upon environment, thereby allowing an actor of making the habituated body schema to recognize environment. Third, habit makes the mind. The habituated body schema is just the mind and the ego of a person who possesses the body schema. Fourth, habit comes to experience the expansion in energy and the expansion in existence. It may be experienced through interrelation among actor's body, tool, and environment. Fifth, habit makes identity of the body. Hence, this just becomes what secures identity of a role. These implications of habit are the formation of body schema, which is maintained with the body of being remembered firmly through being closely connected with the process of neural adaptation. Finally, it sought for possibility of practice as one method of forming body schema for role creating through Deleuze's '-becoming' theory. As 'actual animal-becoming' is real '-becoming' of forming structural transformation in the physical dimension, it meets with what the formation of body schema pursues actuality and reality. This was explained with a concept as saying of 'all '-becoming' molecular' by Deleuze/Guattari. 'Animal of having imitated animal's characteristic- becoming' is formed by which the body schema relies upon environment. In this way, relationship among the body, tool and environment has influence even upon a change in consciousness, thinking, and emotion, thereby being able to be useful for forming body schema in a sense of possibly experiencing ultimately expansion in role, namely, expansion in existence.

For History : Roles of Historians and Archivists - Public Archives, Archivists, and Historians - (역사를 위하여: 아키비스트와 역사가의 역할 -공공기록보존소를 중심으로-)

  • Lee, Sang-min
    • The Korean Journal of Archival Studies
    • /
    • no.6
    • /
    • pp.225-262
    • /
    • 2002
  • Chief Consultant Archives Government Archives & Records Service -table of contents- 1. Introduction 2. Relationship of Historical Studies and Archive 3. Relationship of Archives and Archives 4. Conclusion; Historians, Archives, and Archivists, and Their Roles This essay is mainly written for historians who may have "little or limited experience" in dealing with archives and archivists in their course of historical research. It may sound very ridiculous to say that "historians have little or limited experience" in using archives but it is also true that many Korean historians have depended on various compiled editions of historical materials or personally donated and/or collected materials when they do research, rather than they would visit archives and search for the materials by themselves. This is the main reason for that the public archives in Korea have not served historians well and effectively, and vice versa, that historians have not visited archives sometime with no knowledge of archives, and have not requested opening of archives for their research. It is a simple fact that historian's study depends on the records he/she uses. Without records, there should be no history. Use of archives for historical research is a common thing and a must in modern archives. Records are selected to be preserved in archives for their preservation as well as their future use. Who select the records as archives? Archivists do mostly. Then, what are the criteria for the archivists to chose records as permanent preservable archives? Answers to this fundamental question have been provided by many historians and archivists. The closest answer may be that selecting archivists would be better trained and equipped with historical research and knowledgeable of the major trends in historical research. With his/her own experience of historical research and tracing the trends of historical studies and materials used in the historiography, they could chose better and appropriate records for future use using their prudence and discretion. It also means that historians have had influence on archivists in their selecting archives by providing the theme and context of historical studies of the time. Though not necessarily becoming a historian themselves, selecting or appraising archivists should understand the process of creating the records and should know how they become archives. This is a precondition to become a good archivist. But that's not all. They must know how the archives are used and what archives are used for what purposes. Among many other roles of modern archivists, selecting and describing the archives are the foremost tasks of an archivist. Archivists therefore developed modern methods to select future archives based on functional analysis and records series concept rather than a record file or item as a unit of selection. Historians are users or consumers of the archives held in the archives building or repository. The quality of their study depends on the "quality" of the materials they use. With the help of archivists not to mention of reference service, historians owe much to archivists in having an access to the materials they need, intellectually and physically. Too many closed archives and too long closed archives in the archives repository would benefit neither historians nor archivists. However, archivists can mostly react only to archive requests and demands made by historians for more wide accessibility. Using the FOIA, as in the U.S., or the Information Opening Act, as in case of Korea, historians can promote the use of historical materials as well as promoting accountability and transparence for the benefit to society as whole. In this context, it is vary desirable to establish a close professional relationship between historians and archivists even in the age of information society. At present, historians need more understanding of operation and importance of archives while archives administration need to realize the potential archival demands from research community and civil movement for clean government.

Analysis of Authority Control System in Collecting Repository -from the case of Archival Management System in Korea Democracy Foundation- (수집형 기록관의 전거제어시스템 분석 - 민주화운동기념사업회 사료관리시스템의 사례를 중심으로 -)

  • Lee, Hyun-Jeong
    • The Korean Journal of Archival Studies
    • /
    • no.13
    • /
    • pp.91-134
    • /
    • 2006
  • In general, personally collected archives, manuscripts, are physically badly conditioned and also contextual of the archives and information on the history of production is mostly collected partly in the manuscripts. Therefore they need to control the name of the producers on the archives collected in various ways effectively and accumulate provenance information which is the key element when understanding the production background in the collecting repository. Here, the authority control and provenance information management must be organized from the beginning of acquisition and this means to collect necessary information considering control process of acquisition as well. This thesis is for verifying the necessity of the authority control in collecting repository and accumulation of the provenance information and for suggesting the things to be considered as collecting Archival authority system. For all these, this thesis shows that it has checked out the necessity of the authority control in archival management and archival authority control and researched the standard of archival authority control, work process and accumulation process. Archival provenance information management and authority control in the archival authority control system are organized through the whole steps of the archival management starting from the lead file to the name of the producers at archival registration and archival description at acquisition. And a lot of information is registered and described at the proper point of time and finally all the information including authority control which controls the Heading in the authority management must be organized to use them as an intellectual management of archives and Finding Aids. The features of the Archival authority system are as follows; first of all, Authority file type which is necessary at the archival authority control of democracy movement is made up of the name of the group, person, affair and terminology(subject name). Second of all, basic record structures and description elements in authority collection of Korea Democracy Foundation Archives apply in the paragraph 1 of ISAAR(CPF) adding some necessary elements and details of description rule such as spacing words and using the periods apply in the paragraph 4 of KCR coping with the features of the archival management system. And also the way of input on the authority record is based on EAC(Encoded Archival Context). Third of all, it made users approach to the sources which they want more easily by connecting the authority terms systemically making it possible to connect the relative terms with up and down words, before and after words variously and concretely expanding the term relations rather than earlier traditional authority system which is usually expressed only with relative words (see also). So the authority control of archival management system can effectively collect and manage the function of various and multiple groups and information on main activities as well as its own function which is controlling the Heading and express the multiple and intermediary relationship between archives and producers or between producers and it also provides them with expanded Record information service which satisfies user's various requests through Indexing service. Finally applying in this international standard ISAAR(CPF) through the instance of the authority management like this, it can be referred to making Archival authority system in Collecting repository hereafter by reorganizing the description elements into appropriate formations and setting up the authority file type which is to be managed properly for every service.

Oxidative Desulfurization of Marine Diesel Using Keggin Type Heteropoly Acid Catalysts (Keggin형 헤테로폴리산 촉매를 이용한 선박용 경유의 산화 탈황)

  • Oh, Hyeonwoo;Woo, Hee Chul
    • Clean Technology
    • /
    • v.25 no.1
    • /
    • pp.91-97
    • /
    • 2019
  • Oxidative desulfurization (ODS) has received much attention in recent years because refractory sulfur compounds such as dibenzothiophenes can be oxidized selectively to their corresponding sulfoxides and sulfones, and these products can be removed by extraction and adsorption. In this work, The oxidative desulfurization of marine diesel fuel was performed in a batch reactor with hydrogen peroxide ($H_2O_2$) in the presence of various supported heteropoly acid catalysts. The catalysts were characterized by XRD, XRF, XPS and nitrogen adsorption isotherm techniques. Based on the sulfur removal efficiency of promising silica supported heteropoly acid catalysts, the ranking of catalytic activity was: $30\;H_3PW_{12}/SiO_2$ > $30\;H_3PMo_{12}/SiO_2$ > $30\;H_4SiW_{12}/SiO_2$, which appears to be related with their intrinsic acid strength. The $30\;H_3PW_{12}/SiO_2$ catalyst showed the highest initial sulfur removal efficiency of about 66% under reaction conditions of $30^{\circ}C$, $0.025g\;mL^{-1}$ (cat./oil), 1 h reaction time. However, through the recycle test of the $H_3PW_{12}/SiO_2$ catalyst, significant deactivation was observed, which was attributed to the elution of the active component $H_3PW_{12}$. By introducing cesium cation ($Cs^+$) into the $H_3PW_{12}/SiO_2$ catalyst, the stability of the catalyst was improved with changing the solubility, and the $Cs^+$ ion exchanged catalyst could be recycled for at least five times without severe elution.