• Title/Summary/Keyword: Structural

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Characterization and Distribution of Glycoconjugates in Human Pulmonary Tubercles by Lectin Histochemistry (폐결핵 결절에서 복합당질의 분포에 관한 Lectin 조직화학적 연구)

  • Yoon, Sik;Kim, Ji-Hong;Shin, Cheol-Shik;Jeong, Suk;Son, Mal-Hyun;Song, Sun-Dae;Kim, Jin-Jeong
    • Tuberculosis and Respiratory Diseases
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    • v.41 no.3
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    • pp.248-261
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    • 1994
  • Background: Lectins are proteins or glycoproteins of non-immune origin that recognize a specific sequence of sugar residues. The availability of a large number of lectins has provided the capacity to identify selectively glycoconjugates possessing distinctive chemical structure in diverse sites of highly specialized biological activity. The purpose of the present study was to investigate the lectin binding patterns of various components in human pulmonary tubercles. Method: Biopsy specimens of tuberculous lung were obtained from male adult patients who underwent a surgical resection for severe pulmonary tuberculosis. The specimens were processed and stained with 13 kinds of biotinylated lectins according to some modification of Hsu and Raine's methods. Results: 1) In the caseous necrotic lesions, BS $I-B_4$ showed negative reaction and BS I were also negative except some irregularly-shaped cells located in the marginal zone. All other lectins, however, showed a positive reaction with various binding patterns. 2) The epithelioid cells were broadly divided into three groups according to the reaction patterns in the cytoplasms and cell membranes. 3) WGA, ECL, PHA-L, PHA-E and LCA showed strong staining in the lymphocytes. 4) SBA showed a different binding patterns between the endothelial layers located in the region beyond the fibrous layers and those located within the fibrous layers. 5) PNA showed a positive reaction in the outer 1/3 to 1/2 of the fibrous layer, but showed no staining in the inner 1/2 to 2/3 of the fibrous layers. Conclusion: The present lectin histochemical study provided a useful information to assess the characterization and distribution of various glycoconjugates in each constituent of human pulmonary tubercles. The results demonstrate structural differences in the glycoconjugate composition of various components of the tubercles and reveal changes in glycosylation in the components during soft tubercle formation. This study provides a new data useful for the studies on the pathogenesis and pathology of human pulmonary tubercles.

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The Expression of IL-8 and GRO$\alpha$/MGSA in HUVEC Stimulated by the TNF-$\alpha$ and IL-1 (TNF-$\alpha$와 IL-1 자극에 의한 제대정맥내피세포에서의 IL-8 및 GRO/MGSA의 발현)

  • Song, Jeong-Sup;Shin, Moon-Sun;Ahn, Joong-Hyun;Moon, Hwa-Sik;Park, Sung-Hak
    • Tuberculosis and Respiratory Diseases
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    • v.46 no.3
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    • pp.338-349
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    • 1999
  • Polymorphonuclear leukocytes(PMN) are the predominant inflammatory cells recruited in acute lung injury such as adult respiratory distress syndrome, pneumonia and also chronic lung disease such as idiopathic pulmonary fibrosis and pulmonary emphysema. Interleukin-8(IL-8) is an 8,000 D protein produced by many cells and has potent neutrophil chemoattractant and activating properties. The GRO, also called melanoma growth-stimulatory activity(MGSA), referring to a peptide of 73 amino acids, was reported to be mitogenic for cultured human melanoma cells. Mature GRO/MGSA has marked sequence similarity to IL-8. In view of the structural similarities to IL-8, it was of particular interest to test GRO for neutrophil activating and chemotactic properties. We found a significant release of IL-8 and GRO/MGSA from the cultured human umbilical vein endothelial cell(HUVEC) which was stimulated either with TNF$\alpha$ or IL-1$\beta$ and also found the expression of IL-8 and GRO/MGSA mRNA. Neutrophil chemotactic activity was enhanced in accordance with the increased IL-8 and GRO/MGSA. Our study also suggest that the IL-8 is more important in the increased neutrophil chemotactic activity than GRO/MGSA when endothelial cell is stimulated with TNF$\alpha$ or IL-1$\beta$ in vitro.

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Effects of Green Tea Catechin on Bone Disorder in Long-Term Cadmium Treated Rats (만성 카드뮴 처치 쥐에서 골조직 장애에 미치는 녹차 Catechin의 영향)

  • 최정화;김용진;이순재
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.30 no.6
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    • pp.1253-1259
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    • 2001
  • The purpose of this study was to investigate the effects of green tea catechin on change of bone tissue in long-term cadmium treated rats. Sprague-Dawley male rats weighing 100$\pm$10 g were randomly assigned to one normal group and three cadmium treated groups. Cadmium groups were classified to catechin free diet group (Cd-0C group), 0.25% catechin diet group (Cd-0.25C group) and 0.5% catechin diet group (Cd-0.5C group) according to the levels of catechin supplement. Animals were raised for 20 weeks. Cadmium were supplied as drinking water of 50 ppm Cd$^{2+}$. Effects of catechin were analyzed on changes of bony tissue in long-term cadmium treated rats by determining the accumulated cadmium in bone and bone mineral density and micro- photographs of bony tissue. The cadmium accumulation of tibia and femur were higher in Cd-treated groups than in normal group, but they was lowered by catechin supplementation. The bone mineral density (BMD) of tibia and femur in Cd-0C group was significantly lower than in normal group, but it of catechin supplemetation group was similar to normal group. Microphological changers were appeared under a light microscope and an electro microscope reveal no structural changes in bony spicules, marrow cell distribution and cellular morphology in all groups. The bone weight and length tend to decrease in Cd-0C groups. Catechin supplementation in long-term cadmium treated rats depressed the cadmium accumulation in bony tissue that led to improve the bone mineral density in tibia and femur.r.

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Changes of Leaf Area Index, Physiological Activities and Soil Water in Tricholoma matsutake Producing Pine Forest Ecosystem (송이산 소나무림 생태계에서 엽면적지수와 생리적활동 및 토양수분의 변화)

  • Koo, Chang-Duck;Ka, Kang-Hyun;Park, Won-Chul;Park, Hyun;Ryu, Sung-Ryul;Park, Yong-Woo;Kim, Tae-Heon
    • Journal of Korean Society of Forest Science
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    • v.96 no.4
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    • pp.438-447
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    • 2007
  • The purpose of this study was to understand the ecosystem structure and function and soil water changes in Tricholoma matsutake producing pine stands. The investigated stands were pine forest in Sogrisan National Park in Chungbuk-do of Korea. For the purpose we investigated main vegetation, leaf area index(LAI) as ecosystem structural factors and measured photosynthesis, transpiration, xylem water potential, and soil water changes as ecosystem functional factors. Vertical vegetation structure of the site was composed of Pinus densiflora as a overstory species, Quercus mongolica as midstory, Rhododendron mucronulatum, R. schlippenbachii and Fraxinus sieboldiana as understory ones. In the stands LAI was 3.8 during June to September, 2.6 in October and 2.1 during November to April. Photosyntheses of the trees were 6.0 to $7.0{\mu}mol\;CO_2/m^2/s$ in August, and for P. densiflora about $4.0{\mu}mol\;CO_2/m^2/s$ and for Q. mongolica $2.0{\mu}mol\;CO_2/m^2/s$ in mid October. However, R. mucronulatum stopped fixing $CO_2$ and F. sieboldiana shed off the leaves already in mid October. Transpirations were 2.5 to $3.5mmol\;H_2O/m^2/s$ in late August and about $1.0mmol/H_2O/m^2/s$ in mid October. Plant water potentials were -10 to -22 bars for P. densiflora and -5 to -12 bars for the other woody species. The lowest potentials was in late August and highest in late October. Soil water in the stand was closely related to topography. Soil water contents were 7 to 11% at the ridge, 8 to 15% at the hillside and 11 to 19% at the base. Soil temperatures were 0.2 to $0.4^{\circ}C$ higher in T. matustuake colony than noncolony. Mid September soil temperature decreased to $19^{\circ}C$ at which T. matsutake forms primordia. In T. matsutake colony soil moisture was 0.5 to 2.0% lower due to metabolism for consuming water. We suggest that the complicate relationships between ecosystem structure and function in Tricholoma matsutake producing pine stand need to be further investigated.

User-Perspective Issue Clustering Using Multi-Layered Two-Mode Network Analysis (다계층 이원 네트워크를 활용한 사용자 관점의 이슈 클러스터링)

  • Kim, Jieun;Kim, Namgyu;Cho, Yoonho
    • Journal of Intelligence and Information Systems
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    • v.20 no.2
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    • pp.93-107
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    • 2014
  • In this paper, we report what we have observed with regard to user-perspective issue clustering based on multi-layered two-mode network analysis. This work is significant in the context of data collection by companies about customer needs. Most companies have failed to uncover such needs for products or services properly in terms of demographic data such as age, income levels, and purchase history. Because of excessive reliance on limited internal data, most recommendation systems do not provide decision makers with appropriate business information for current business circumstances. However, part of the problem is the increasing regulation of personal data gathering and privacy. This makes demographic or transaction data collection more difficult, and is a significant hurdle for traditional recommendation approaches because these systems demand a great deal of personal data or transaction logs. Our motivation for presenting this paper to academia is our strong belief, and evidence, that most customers' requirements for products can be effectively and efficiently analyzed from unstructured textual data such as Internet news text. In order to derive users' requirements from textual data obtained online, the proposed approach in this paper attempts to construct double two-mode networks, such as a user-news network and news-issue network, and to integrate these into one quasi-network as the input for issue clustering. One of the contributions of this research is the development of a methodology utilizing enormous amounts of unstructured textual data for user-oriented issue clustering by leveraging existing text mining and social network analysis. In order to build multi-layered two-mode networks of news logs, we need some tools such as text mining and topic analysis. We used not only SAS Enterprise Miner 12.1, which provides a text miner module and cluster module for textual data analysis, but also NetMiner 4 for network visualization and analysis. Our approach for user-perspective issue clustering is composed of six main phases: crawling, topic analysis, access pattern analysis, network merging, network conversion, and clustering. In the first phase, we collect visit logs for news sites by crawler. After gathering unstructured news article data, the topic analysis phase extracts issues from each news article in order to build an article-news network. For simplicity, 100 topics are extracted from 13,652 articles. In the third phase, a user-article network is constructed with access patterns derived from web transaction logs. The double two-mode networks are then merged into a quasi-network of user-issue. Finally, in the user-oriented issue-clustering phase, we classify issues through structural equivalence, and compare these with the clustering results from statistical tools and network analysis. An experiment with a large dataset was performed to build a multi-layer two-mode network. After that, we compared the results of issue clustering from SAS with that of network analysis. The experimental dataset was from a web site ranking site, and the biggest portal site in Korea. The sample dataset contains 150 million transaction logs and 13,652 news articles of 5,000 panels over one year. User-article and article-issue networks are constructed and merged into a user-issue quasi-network using Netminer. Our issue-clustering results applied the Partitioning Around Medoids (PAM) algorithm and Multidimensional Scaling (MDS), and are consistent with the results from SAS clustering. In spite of extensive efforts to provide user information with recommendation systems, most projects are successful only when companies have sufficient data about users and transactions. Our proposed methodology, user-perspective issue clustering, can provide practical support to decision-making in companies because it enhances user-related data from unstructured textual data. To overcome the problem of insufficient data from traditional approaches, our methodology infers customers' real interests by utilizing web transaction logs. In addition, we suggest topic analysis and issue clustering as a practical means of issue identification.

Selection Model of System Trading Strategies using SVM (SVM을 이용한 시스템트레이딩전략의 선택모형)

  • Park, Sungcheol;Kim, Sun Woong;Choi, Heung Sik
    • Journal of Intelligence and Information Systems
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    • v.20 no.2
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    • pp.59-71
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    • 2014
  • System trading is becoming more popular among Korean traders recently. System traders use automatic order systems based on the system generated buy and sell signals. These signals are generated from the predetermined entry and exit rules that were coded by system traders. Most researches on system trading have focused on designing profitable entry and exit rules using technical indicators. However, market conditions, strategy characteristics, and money management also have influences on the profitability of the system trading. Unexpected price deviations from the predetermined trading rules can incur large losses to system traders. Therefore, most professional traders use strategy portfolios rather than only one strategy. Building a good strategy portfolio is important because trading performance depends on strategy portfolios. Despite of the importance of designing strategy portfolio, rule of thumb methods have been used to select trading strategies. In this study, we propose a SVM-based strategy portfolio management system. SVM were introduced by Vapnik and is known to be effective for data mining area. It can build good portfolios within a very short period of time. Since SVM minimizes structural risks, it is best suitable for the futures trading market in which prices do not move exactly the same as the past. Our system trading strategies include moving-average cross system, MACD cross system, trend-following system, buy dips and sell rallies system, DMI system, Keltner channel system, Bollinger Bands system, and Fibonacci system. These strategies are well known and frequently being used by many professional traders. We program these strategies for generating automated system signals for entry and exit. We propose SVM-based strategies selection system and portfolio construction and order routing system. Strategies selection system is a portfolio training system. It generates training data and makes SVM model using optimal portfolio. We make $m{\times}n$ data matrix by dividing KOSPI 200 index futures data with a same period. Optimal strategy portfolio is derived from analyzing each strategy performance. SVM model is generated based on this data and optimal strategy portfolio. We use 80% of the data for training and the remaining 20% is used for testing the strategy. For training, we select two strategies which show the highest profit in the next day. Selection method 1 selects two strategies and method 2 selects maximum two strategies which show profit more than 0.1 point. We use one-against-all method which has fast processing time. We analyse the daily data of KOSPI 200 index futures contracts from January 1990 to November 2011. Price change rates for 50 days are used as SVM input data. The training period is from January 1990 to March 2007 and the test period is from March 2007 to November 2011. We suggest three benchmark strategies portfolio. BM1 holds two contracts of KOSPI 200 index futures for testing period. BM2 is constructed as two strategies which show the largest cumulative profit during 30 days before testing starts. BM3 has two strategies which show best profits during testing period. Trading cost include brokerage commission cost and slippage cost. The proposed strategy portfolio management system shows profit more than double of the benchmark portfolios. BM1 shows 103.44 point profit, BM2 shows 488.61 point profit, and BM3 shows 502.41 point profit after deducting trading cost. The best benchmark is the portfolio of the two best profit strategies during the test period. The proposed system 1 shows 706.22 point profit and proposed system 2 shows 768.95 point profit after deducting trading cost. The equity curves for the entire period show stable pattern. With higher profit, this suggests a good trading direction for system traders. We can make more stable and more profitable portfolios if we add money management module to the system.

An Evaluation on Visitor Satisfaction in Waterfront Park (수변공원의 이용 만족도 평가)

  • Chang, Min-Sook;Chang, Byung-MKoon
    • Journal of the Korean Institute of Landscape Architecture
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    • v.38 no.3
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    • pp.41-52
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    • 2010
  • The purpose of this paper is to evaluate visitor satisfaction(VS) in waterfront parks in terms of resources, facilities, embodiment of theme(ET), site composition(SC), relaxation activity space(RAS), and dynamic activity space(DAS), which are supply-side components in the planning process of waterfront parks, in order to answer the research question; 'How is visitor satisfaction of waterfront parks determined?' After reviewing the literature on parks and the building process of waterfront parks in Korea, we constructed a conceptual framework and have ascertained a research hypothesis. We had obtained data through a questionnaire survey from 327 visitors at waterfront parks, based on the quota sampling method. We have analyzed the data using the path analysis method. We found that: 1) The direct effects of resources and facilities on VS turned out to be 0.273 and 0.306, respectively while the indirect effects are 0.114, 0.170, respectively. 2) The direct effects of SC, as a component of the planning process on VS, turned out to be 0.243 while that of ET had no affect on VS. The indirect effect of ET and SC on VS turned out to be 0.059 and 0.018, respectively. 3) The direct effects of RAS on VS turned out to be 0.129 while the indirect effects of RAS and DAS on VS turned out to be 0.002 and 0.017, respectively. 4) The size of causal effect, in order, were facilities, resources, SC, RAS, ET, and DAS. 5) Resources and facilities, as a park foundation, compose 64.84 percent of total causal effect while ET and SC have 24.04 percent and RAS and DAS have 11.12 percent, respectively. These research results imply that: 1) Existing waterfront parks should be regenerated with the embodiment of water related theme and with improved facilities for RAS and visitor programs and/or facilities for DAS. 2) The relationship among ET, SC, RAS and DAS should be increased for a significant improvement of VS, and 3) A process-oriented approach turned out to be highly useful for the development of substantive theory and methodology. It is recommended that a structural equation model on waterfront parks be developed using more empirical data and this approach be widely applied for testing its validity.

An Evaluation Model on Supply Factors of Urban Park (도시공원의 공급인자 평가모형)

  • Chang, Byung-Moon
    • Journal of the Korean Institute of Landscape Architecture
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    • v.38 no.1
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    • pp.1-11
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    • 2010
  • The purpose of this paper is to evaluate supply factors of urban parks to answer the research question: What are the causal effects of supply factors of urban parks on visitor satisfaction? After reviewing the literature and the Korean park planning process, we constructed a conceptual framework and have formulated the hypothesis of this research. We had obtained data through a questionnaire, which surveyed 452 visitors at 8 urban parks in Daegu Metropolitan City in 2008, based on a stratified sampling method. After the elimination of 96 unsuitable samples, we have analyzed the data using descriptive statistical methods, Pearson's correlation analysis and a path analysis method. We have found that: 1) While the direct and indirect effect of accessibility(ACC) on visitor satisfaction(VS) turned out to be 0.184 and 0.220, respectively, the indirect effect of information(IFM) and promotion(PRM) on VS turned out to be 0.101 and 0.177, respectively. 2) While the direct and indirect effect of service(SVR) on VS turned out to be 0.130 and 0.236, respectively, the direct effect of ACC turned out to be 0.698. 3) While the direct effect of ACC, SVR and attraction(ATT) on VS turned out to be 0.184, 0.130 and 0.698, respectively, composing 67.96% of causal effect, the indirect effect of ACC, IFM, PRM and SVR on VS turned out to be 0.220, 0.101, 0.177 and 0.236, respectively, composing 42.04% of causal effect. 4) The magnitude of causal effect of supply factors on VS turned out to be ATT(39.98%), ACC(23.14%), SVR(20.96%), PRM(10.14%) and IFM(5.78%) in order, and 5) the causal effect of external supply factors of ACC, IFM and PRM compose 39.06% of the causal effect while that of the internal supply factors of SVR and ATT is 69.94%. The research results suggest that: 1) Planning for park marketing strategy and remedial directions for existing urban parks, in order to increase visitor satisfaction, be focused on IFM and PRM, especially. 2) The research approach and path analysis method adopted by this research be valid and highly useful for planning and evaluation of other recreation areas. It is recommended that: 1) Structural Equation Model on supply factors of urban parks be established in the future. 2) Evaluation of supply factors by type of urban park be performed.

A Study on Principle of Kigong mentioned in the lecture on Truth of ${\ll}$Samilshingo${\gg}$(三一神誥) and its Interrelationship with Oriental Medicine (${\ll}$삼일신고(三一神誥).진리훈(眞理訓)${\gg}$에 나타난 氣功原理(氣功原理) 및 한의학(韓醫學)과 의 상관성(相關性)에 관(關)한 연구(硏究))

  • Ban Chang-Youl;Jee Seon-Young;Gang Go-Sin
    • Journal of Korean Medical Ki-Gong Academy
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    • v.4 no.2
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    • pp.153-186
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    • 2000
  • Jigam(止感), Josik(調息), Kumchock(禁觸), from the lecture on Truth of ${\ll}Samilshingo{\gg}$(三一神誥) treat three elements of Kigong, regulation of mental activties, regulation of breathing and adjustment of posture and there are some similar mentions with the view of human body based on oriental medicine like those Samjin(三眞), Sammang(三妄), Samdo(三途) and Sippalkyoung(十八境) ect. Thus as a result of comparison and observation about the interrelationships between principle of Kigong in the lecture on Truth of ${\ll}Samilshingo{\gg}$(三一神誥) and oriental medicine. I have conclusion as follows. 1. According to the lecture on Truth, the components of human body are the one and only Samjin(三眞), Sammang(三妄) and Samdo(三途) resulted from facing Samjin(三眞) to Sammang(三妄) and Sippalkyoung(十八境). This fact presents the principle of human change. 2. the principle of Kigong mentioned in the lecture on Truth shows the original Ilshin(一神) on the basis of Samjin(三眞), Sammang(三妄), Samdo(三途) and Sippalkyoung(十八境). This makes common, unity and sound Sim(心), Ki(氣) and Shin(身), Sammang(三妄) through Jigam(止感), Josik(調息) and Kumchock(禁觸), be versed, intellected and guaranteed Sung(性), Myoung(命) and Jung(精), Samjin(三眞) and emit Kyun(見), Mun(聞), Ji(知) and haeng(行), Sadaeshingi(四大神機) and finally all these are harmonized into Duk(德), Hye(慧) and Ryuk(力), Samdae(三大) which is the entity of God. 3. Samsipyookjongmyowhasang(三十六種妙化相) is an ascetic practice done after a chulin(哲人) deduce Ji(止), Jo(調) and Kum(禁), Sambup(三法) on the basis of the lecture on Truth. So I suppose it correlates nature's six elements. Kong(空)(Chun(天)). Yol(熱)(Wha(火)). Jin(震(Jeon(電)), Seup(濕)(Shoo(水)), Han(寒)(Poong(風)) and Ko(固)(Ji(地)), human's Samjin(三眞), Sung(性), Myoung(命) and Jung(精) and Sammang(三妄), Sim(心), Ki(氣) and Shin(身) and makes clear the principle of discipline. 4. In comparison with Samjin(三眞) and Sammang(三妄) says from the lecture on Truth and the Three Essential Elements of the body construction(三寶) from oriental medicine, Samjin(三眞) and Sammang(三妄) as factors of human body in the concept of practical knowledge. That is the one and only Samjin(三眞) in terms of the Three Essential Elements of the body construction(三寶) is considered a structural principle for every single person and Sammang(三妄) is considered a functional form for each individual. And it can be Sung(性)+Sim(心)=Spirit(神), Myoung(命)+Ki(氣)=Vital Force(氣) and Jung(精)+Shin(身)=True Essence(精). 5. In comparison with Sippalkyoung(十八境) of Samdo(三途) from the lecture on Truth and three medical causes of disease, Gamdoyookkyoung(感途六境) is similar with endopathic cause caused by Naesangchiljung(內傷七情), Sikdoyukkyoung(息途六境) is similar with exopathic cause by six climatic conditions in excess as pathogenic factors(六淫) and Yoegi(?氣) and Chokdoyukkyoung(觸途六境) is similar with non-endo-exopathogenic causes by diet imbalance, fatigue, intemperance in sexual life and trauma etc. 6. In the lecture on Truth, the Chulin(哲人) who discipline Sambup(三法), Sangchul(上哲), Choongchul(中哲) and Hachul(下哲) can be compared with Kigong expert(health preserving expert) such as the Spiritual Men(眞人), the Sapients(至人), the Sages(聖人) and the Men of Exellent Virtue(寶人) in the Sang Gu Tian Zhen Lun of the Huang Ti Nei Ching Su Wen(素問 上古天眞論) and then Sangchul(上哲) is the Spiritual Men(眞人), Choongchul(中哲) is the Sapients(至人) and Hachul(下哲) is the Sages(聖人) while the men of Exellent Virtue(賢人) is inferior to Chulin(哲人) when he goes to extremes.

Etherification of n-Butanol to Di-n-Butyl Ether over H3+xPW12-xNbxO40 (x=0, 1, 2, 3) Keggin and H6+xP2W18-xNbxO62 (x=0, 1, 2, 3) Wells-Dawson Heteropolyacid Catalysts (Keggin형 H3+xPW12-xNbxO40 (x=0, 1, 2, 3) 및 Wells-Dawson형 H6+xP2W18-xNbxO62 (x=0, 1, 2, 3) 헤테로폴리산 촉매를 이용한 n-Butanol로부터 Di-n-Butyl Ether의 제조)

  • Kim, Jeong Kwon;Choi, Jung Ho;Yi, Jongheop;Song, In Kyu
    • Korean Chemical Engineering Research
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    • v.50 no.2
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    • pp.251-256
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    • 2012
  • Etherification of n-butanol to di-n-Butyl Ether was carried out over Keggin $H_{3+x}PW_{12-x}Nb_xO_{40}$ (x=0, 1, 2, 3) and $H_{6+x}P_2W_{18-x}Nb_xO_{62}$ (x=0, 1, 2, 3) Wells-Dawson heteropolyacid catalysts. Niobium-substituted Keggin and Wells-Dawson heteropolyacid catalysts with different niobium content were prepared. Successful preparation of the catalysts was confirmed by FT-IR, ICP-AES, and $^{31}P$ NMR analyses. Their acid properties were determined by $NH_3$-TPD (Temperature-Programmed Desorption) measurements. Heteropolyacid catalysts showed different acid properties depending on niobium content in both series. The correlation between acid properties of heteropolyacid catalysts and catalytic activity was then established. Acidity of Keggin and Wells-Dawson heteropolyacid catalysts decreased with increasing niobium content, and conversion of n-butanol and yield for di-n-butyl ether increased with increasing acidity of the catalysts, regardless of the identity of heteropolyacid catalysts (without heteropolyacid structural sensitivity). Thus, acidity of heteropolyacid catalysts served as an important factor determining the catalytic performance in the etherification of n-butanol to di-n-Butyl Ether.