• Title/Summary/Keyword: 가교

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Behavior of NOM Fouling in Submerged Photocatalytic Membrane Reactor Combined with $TiO_2$ Nanoparticles ($TiO_2$ 나노입자/UV 결합 침지형 중공사막 시스템에서 자연유기물의 파울링거동)

  • Park, Seung-Soo;Seo, Hyung-Jun;Kim, Jeong-Hwan
    • Membrane Journal
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    • v.21 no.1
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    • pp.46-54
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    • 2011
  • In this study, combined effect of airflow rate, $TiO_2$ concentration, solution pH and $Ca^{+2}$ addition on HA (humic acid) fouling in submerged, photocatalytic hollow-fiber microfiltraiton was investigated systematically. Results showed that UV irradiation alone without $TiO_2$ nanoparticles could reduce HA fouling by 40% higher than the fouling obtained without UV irradiation. Compared to the HA fouling without UV irradiation and $TiO_2$ nanoparticles, the HA fouling reduction was about 25% higher only after the addition of $TiO_2$ nanoparticles. Both adsorptive and hydrophilic properties of $TiO_2$ nanoparticles for the HA can be involved in mitigating membrane fouling. It was also found that the aeration itself had lowest effect on fouling mitigation while the HA fouling was affected significantly by solution pH. Transient behavior of zeta potential at different solution pHs suggested that electrostatic interactions between HA and $TiO_2$ nanoparticles should improve photocatalytic efficiency on HA fouling. $TiO_2$ concentration was observed to be more important factor than airflow rate to reduce HA fouling, implying that surface reactivity on $TiO_2$ naoparticles should be important fouling mitigation mechanisms in submerged, photocatalyic microfiltraiton. This was further supported by investigating the effect of $Ca^{+2}$ addition on fouling mitigation. At higher pH (= 10), addition of $Ca^{+2}$ can play an important role in bridging between HA and $TiO_2$ nanoparticles and increasing surface reactivity on nanoparticles, thereby reducing membrane fouling.

Development and Application of Okara-based Adhesives for Plywood Panels (두부비지를 이용한 합판용 접착제의 개발 및 적용)

  • Oh, Sei-Chang;Ahn, Sye-Hee;Choi, In-Gyu;Jeong, Han-Seob;Yoon, Young-Ho;Yang, In
    • Journal of the Korean Wood Science and Technology
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    • v.36 no.3
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    • pp.30-38
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    • 2008
  • Petroleum-based resin adhesives have extensively been used for the production of wood panels. However, with the increase of manufacturing cost and the environmental issue, such as the emission of volatile organic compounds, of the adhesive resins, it is necessary to be developed new adhesive systems. In this study, the potential of okara, which is a residue wasted from the production of tofu, for the development of bio-based adhesives was investigated. At first, the physical and chemical properties of okara were examined. After okara was hydrolyzed in acidic and/or alkaline solutions, okara-based adhesive resins were formulated with the mixtures of the okara hydrolyzates and phenol formaldehyde (PF) prepolymer. The adhesive resins were used for the fabrication of plywood panels, and then the adhesive strength and formaldehyde emission of the plywood panels were measured to examine the applicability of the resin adhesives for the production of plywood panels. The solids content and pH of the okara used in this study were around 20% and weak acidic state, respectively. In the analysis of its chemical composition, the content of carbohydrate was the highest, and followed by protein. The shear strengths of plywood fabricated with okara-based resin adhesives exceeded a minimum requirement of KS standard for ordinary plywood, but its wood failure did not reach the minimum requirement. In addition, the formaldehyde emissions of all plywood panels were higher than that of E1 specified in the KS standard. Based on these results, okara has the potential to be used as a raw material of environmentally friendly adhesive resin systems for the production of wood panels, but further researches - biological hydrolysis of okara and various formulations of PF prepolymer - are required to improve the adhesive strength and formaldehyde emission of okara-based resin adhesives.

The Changes of Hardness and Microstructure of Dongchimi according to different kinds of water (물의 종류를 달리한 동치미의 경도 변화 및 세포벽 관찰)

  • 심영현;안기정;김지은
    • Korean journal of food and cookery science
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    • v.20 no.1
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    • pp.86-94
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    • 2004
  • The purpose of this study was to investigate the changes of hardness and microstructure of Dongchimi cooked with various source of water(distilled water, purified water, Cho Jung Carbonated Natural water). This study was conducted to observe the changes of pH, total acidity, salt content, turbidity, texture and microstructure. Dongchimi cooked with source of water of water was fermented at 10$^{\circ}C$ for 46 days. The changes of pH on Dongchimi cooked with various source of water decreased in all samples during fermentation period, and then showed a slowly decrease after 12 days of fermentation. The total acidity of Dongchimi cooked with Cho Jung Carbonated Natural water was arrived slowly at best tasting condition 0.3 ∼ 0.4 point compared with other conditions. So Dongchimi cooked with Cho Jung Carbonated Natural water was continued to the best tasting condition for end of fermentation. At early stage of fermentation, the changes of turbidity of Dongchimi used Cho Jung Carbonated Natural water showed highly as compared with other test condition for 12th days of fermentation. The maximum cutting force of chinese radish of Dongchimi showed the highest value among all at the 25th day of ripening and then decreased gradually. The maximum cutting force of chinese radish of Dongchimi used Cho Jung Carbonated Natural water was the highest compared with other conditions at 25th day of fermentation. The calcium content of Dongchimi juice used Cho Jung Carbonated Natural water was observed hish at the early stage of fermentation and showed the highest value at 25th day of ripening. The calcium content of chinese radish and Dongchimi juice of Dongchimi cooked with water purifier was lower than that of Dongchimi cooked with Cho Jung Carbonated Natural water, and was higher than that of Dongchimi cooked with Distilled water at the early stage of fermentation. The magnesium content in all samples increased gradually from the early stage of fermentation. The microstructure showed disintegration appearance of middle lamella and cell wall during fermentation period.

A Study of Jeong Yak-yong's Minor Annotation of Elementary Learning and Private Examination of Classic of the Mind (정약용(丁若鏞)의 『소학지언(小學枝言)』 · 『심경밀험(心經密驗)』에 관한 연구(硏究) - 윤리적(倫理的) 실천론(實踐論)을 중심(中心)으로-)

  • Seo, Geun-sik
    • The Journal of Korean Philosophical History
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    • no.23
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    • pp.217-244
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    • 2008
  • This research studied Minor Annotation of Elementary Learning("小學枝言") and Private Examination of Classic of the Mind("心經密驗") from the ethical perspective. Minor Annotation of Elementary Learning and Private Examination of Classic of the Mind are writings that play a role of bridge between Chinese classics(經學) and Theory of Statecraft(經世論). These two essays were written for the purpose of putting virtue into practice, which had been attained by studying Chinese classics, through a vehicle called Theory of Statecraft. If Minor Annotation of Elementary Learning called as a book of cultivation of outward morality or outward behavior, then Private Examination of Classic of the Mind is the book for cultivation of inward temperament. The 'practice' emphasized by Dasan through these two essays denotes ceaseless efforts toward goodness or virtue. Such efforts can be interpreted as 'ethical practice', if looked at from the perspective of aggressive struggle toward virtue. Dasan, in these two essays, had stressed to practice Good(善) through positive and lively actions. The matter of Good and Bad(善惡) in humans is not associated with their mind, but related to their practice. That is to say, humans may turn out to be good through means of 'ethical practice'. For Dasan, 'ethical practice' toward Good should have to be continued and upheld not only in the course of self-cultivation, but also in 'establishing relationship' with others. Such an assertion of Dasan was to lay emphasis on accomplishment of 'ethical practice' toward Good amid close relationship between personal and social ethics. Also, Dasan had emphasized free will(自由意志) in humans. This means that Good and Bad will be determined according to humans' free will, and to the same extent, that humans are responsible for its consequence. It is noted that Dasan had stressed that any human having free will should have to be a 'man of virtue'(君子) through means of 'ethical practice'.

The Establishment of Seongjusa Temple and the Production of Iron Buddhas (성주사 창건과 철불 조성 연구)

  • Kang Kunwoo
    • MISULJARYO - National Museum of Korea Art Journal
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    • v.104
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    • pp.10-39
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    • 2023
  • Seongjusa Temple was founded in Boryeong in Chungcheongnam-do Province by Monk Muyeom (800-888), better known as Nanghye Hwasang. After returning from studying in China, Muyeom stayed in the Silla capital city of Gyeongju for a period. He later settled in a temple that was managed by the descendants of Kim In-mun (629-694). He then restored a burned-out temple and opened it in 847 as a Seon (Zen) temple named Seongjusa. It prospered and grew to become a large-scale temple with several halls within its domains. The influence of Seongjusa in the region can be seen in the Historical Record of Seongjusa Temple on Sungamsan Mountain, which relates that there were seventy-three rooms within the domains of the temple. What is most notable in the record is that the temple is referred to as "栴檀林九間," which means either "a structure with nine rooms built with Chinese juniper wood" or "a place that houses Chinese juniper wood and has nine rooms." Regardless of the interpretation, Seongjusa Temple had a large amount of juniper wood. Around this time, the term "juniper" referred to the olibanum tree (Boswellia sacra) native to the islands of Java and Sumatra in Southeast Asia. It is presumed that at some point after the death of Jang Bogo, the maritime forces that controlled the southwestern coast of Korea may have acquired a large amount of Southeast Asian olibanum wood and offered it to Seongjusa Temple. During the reign of King Munseong, Kim Yang (808-857) patronized Seongjusa Temple and its head monk Muyeom, who enjoyed a lofty reputation in the region. He sought to strengthen his own position as a member of the royal lineage of King Muyeol and create a bridge between the royal family and Seongjusan Buddhist sect. The court of King Wonseong designated Seongjusa Temple as a regional base for the support of royal authority in an area where anti-royal sentiment remained strong. Monk Muyeom is believed to have created an iron Buddha to protect the temple, enlighten the people, and promote regional stability. Given that the Seongjusa community had expanded to include more than 2,000 followers, the iron Buddha at Seongjusa Temple would have been perceived as an image that rallied the local residents. It is assumed that there were two iron Buddhas at Seongjusa Temple. The surviving parts of these Buddhas and the size of their pedestals suggest that they were respectively enshrined in the Geumdang Main Hall and the Samcheonbuljeon Hall of Three Thousand Buddhas. It is presumed that the first iron Buddha in Geumdang was a large statue over two meters in height and the second one was medium-sized with the height over one meter. The Historical Record of Seongjusa Temple on Sungamsan Mountain contains the phrase "改創選法堂五層重閣" which indicates that a multistoried Geumdang was newly built to enshrine a large Buddha sculpture like the first iron Buddha when Seongjusa Temple was founded. Also, according to the Stele of Seongjusa Temple and the surviving finger fragments, the first Buddha was making the fear-not and wish-granting (abhayavarada) mudras. The main Buddha of Seongjusa Temple is possibly Nosana Buddha, just like the main Buddhas at the contemporaneous temples Silsangsa, Borimsa, and Samhwasa. Given that Monk Muyeom studied Hwaeom teachings in his early years and received royal patronage upon his return, it is believed that the retro tendencies of the Hwaeom school, centered on the royal family of the Silla Dynasty, were reflected in Seongjusa temple.