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The Pattern Analysis of Financial Distress for Non-audited Firms using Data Mining (데이터마이닝 기법을 활용한 비외감기업의 부실화 유형 분석)

  • Lee, Su Hyun;Park, Jung Min;Lee, Hyoung Yong
    • Journal of Intelligence and Information Systems
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    • v.21 no.4
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    • pp.111-131
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    • 2015
  • There are only a handful number of research conducted on pattern analysis of corporate distress as compared with research for bankruptcy prediction. The few that exists mainly focus on audited firms because financial data collection is easier for these firms. But in reality, corporate financial distress is a far more common and critical phenomenon for non-audited firms which are mainly comprised of small and medium sized firms. The purpose of this paper is to classify non-audited firms under distress according to their financial ratio using data mining; Self-Organizing Map (SOM). SOM is a type of artificial neural network that is trained using unsupervised learning to produce a lower dimensional discretized representation of the input space of the training samples, called a map. SOM is different from other artificial neural networks as it applies competitive learning as opposed to error-correction learning such as backpropagation with gradient descent, and in the sense that it uses a neighborhood function to preserve the topological properties of the input space. It is one of the popular and successful clustering algorithm. In this study, we classify types of financial distress firms, specially, non-audited firms. In the empirical test, we collect 10 financial ratios of 100 non-audited firms under distress in 2004 for the previous two years (2002 and 2003). Using these financial ratios and the SOM algorithm, five distinct patterns were distinguished. In pattern 1, financial distress was very serious in almost all financial ratios. 12% of the firms are included in these patterns. In pattern 2, financial distress was weak in almost financial ratios. 14% of the firms are included in pattern 2. In pattern 3, growth ratio was the worst among all patterns. It is speculated that the firms of this pattern may be under distress due to severe competition in their industries. Approximately 30% of the firms fell into this group. In pattern 4, the growth ratio was higher than any other pattern but the cash ratio and profitability ratio were not at the level of the growth ratio. It is concluded that the firms of this pattern were under distress in pursuit of expanding their business. About 25% of the firms were in this pattern. Last, pattern 5 encompassed very solvent firms. Perhaps firms of this pattern were distressed due to a bad short-term strategic decision or due to problems with the enterpriser of the firms. Approximately 18% of the firms were under this pattern. This study has the academic and empirical contribution. In the perspectives of the academic contribution, non-audited companies that tend to be easily bankrupt and have the unstructured or easily manipulated financial data are classified by the data mining technology (Self-Organizing Map) rather than big sized audited firms that have the well prepared and reliable financial data. In the perspectives of the empirical one, even though the financial data of the non-audited firms are conducted to analyze, it is useful for find out the first order symptom of financial distress, which makes us to forecast the prediction of bankruptcy of the firms and to manage the early warning and alert signal. These are the academic and empirical contribution of this study. The limitation of this research is to analyze only 100 corporates due to the difficulty of collecting the financial data of the non-audited firms, which make us to be hard to proceed to the analysis by the category or size difference. Also, non-financial qualitative data is crucial for the analysis of bankruptcy. Thus, the non-financial qualitative factor is taken into account for the next study. This study sheds some light on the non-audited small and medium sized firms' distress prediction in the future.

A Study of Influence of Filgrastim on PET/CT In Diffuse Large B cell Lymphoma (미만성 거대 B 세포 림프종 환자에서 Filgrastim 사용이 PET/CT 영상에 미치는 영향에 대한 고찰)

  • NamKoong, Hyuk;Park, Hoon-Hee;Ban, Yung-Gak;Kang, Sin-Chang;Kim, Sang-Kyoo;Lim, Han-Sang;Lee, Chang-Ho
    • The Korean Journal of Nuclear Medicine Technology
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    • v.13 no.3
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    • pp.17-23
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    • 2009
  • Purpose: It has been known that PET/CT is very valuable in follow-up study of diffuse large B cell lymphoma (DLBCL). Generally, in DLBCL, radiotherapy and chemotherapy has been progressed, because the lesion hasn‘t been limited to one site. And, it has lead to the decrease of leukocyte like neutropenia, due to myelosuppression of chemotherapy. So, in that case, administration of Filgrastim (Granulocyte colony-stimulating factor; G-CSF) is universal. However, in short time after administration, PET/CT has limitation to offer accurate images, through the uptake of $^{18}F$-FDG is increased in the region that is activated bone marrow by hematopoietic growth. Therefore, the aim of this study is that PET/CT in a certain period of time after administration of Filgrastim is able to show normal degree of $^{18}F$-FDG uptake. Materials and Methods: 10 patients under follow-up study of diffuse large B cell lymphoma were examined in this study from January, 2007 to January, 2009 (Male: 4 persons; Female: 6 persons; The mean age: 53.8 years old; The mean weight: 57.3 Kg). Using PET/CT (Discovery STe; GE Healthcare, Milwaukee, WI, USA), whole body images were acquired in 1 hour after $^{18}F$-FDG injection. For image analysis, each ROI ($120\;mm^2$) was drawn on $C^6$ (the sixth C-spine), $L_4$ (the forth L-spine), liver, spleen, and lung, then SUV (Standard Uptake Value)s were measured. We compared with each uptake between in 1-day and 5~7 days after administration of Filgrastim at same patient, so confirmed significance about these by SPSS version 12. Results: In case of $C_6$, $L_4$, spleen, every SUV of 1 day later was remarkably higher than that of 5~7 days later, but liver and lung were similar. Also, the images acquired after 5~7 days distinct remarkably and show normal degree of $^{18}F$-FDG uptake, because uptake of bone was almost disappeared. Conclusions: In this study, each SUV was prominent difference as a period of time after Filgrastim’s administration. And Filgrastim makes concentrate uptake of $^{18}F$-FDG in bone, but, after 5~7 days, bone‘s uptake was greatly decreased. Therefore, we are able to infer a certain period of time that shows normal degree of uptake, by numerical value proven. Also, we consider that this study contribute to advanced study about the other agent like Pegfilgrastim, Lenograstim besides Filgrastim, afterwards.

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The Concentration of Economic Power in Korea (경제력집중(經濟力集中) : 기본시각(基本視角)과 정책방향(政策方向))

  • Lee, Kyu-uck
    • KDI Journal of Economic Policy
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    • v.12 no.1
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    • pp.31-68
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    • 1990
  • The concentration of economic power takes the form of one or a few firms controlling a substantial portion of the economic resources and means in a certain economic area. At the same time, to the extent that these firms are owned by a few individuals, resource allocation can be manipulated by them rather than by the impersonal market mechanism. This will impair allocative efficiency, run counter to a decentralized market system and hamper the equitable distribution of wealth. Viewed from the historical evolution of Western capitalism in general, the concentration of economic power is a paradox in that it is a product of the free market system itself. The economic principle of natural discrimination works so that a few big firms preempt scarce resources and market opportunities. Prominent historical examples include trusts in America, Konzern in Germany and Zaibatsu in Japan in the early twentieth century. In other words, the concentration of economic power is the outcome as well as the antithesis of free competition. As long as judgment of the economic system at large depends upon the value systems of individuals, therefore, the issue of how to evaluate the concentration of economic power will inevitably be tinged with ideology. We have witnessed several different approaches to this problem such as communism, fascism and revised capitalism, and the last one seems to be the only surviving alternative. The concentration of economic power in Korea can be summarily represented by the "jaebol," namely, the conglomerate business group, the majority of whose member firms are monopolistic or oligopolistic in their respective markets and are owned by particular individuals. The jaebol has many dimensions in its size, but to sketch its magnitude, the share of the jaebol in the manufacturing sector reached 37.3% in shipment and 17.6% in employment as of 1989. The concentration of economic power can be ascribed to a number of causes. In the early stages of economic development, when the market system is immature, entrepreneurship must fill the gap inherent in the market in addition to performing its customary managerial function. Entrepreneurship of this sort is a scarce resource and becomes even more valuable as the target rate of economic growth gets higher. Entrepreneurship can neither be readily obtained in the market nor exhausted despite repeated use. Because of these peculiarities, economic power is bound to be concentrated in the hands of a few entrepreneurs and their business groups. It goes without saying, however, that the issue of whether the full exercise of money-making entrepreneurship is compatible with social mores is a different matter entirely. The rapidity of the concentration of economic power can also be traced to the diversification of business groups. The transplantation of advanced technology oriented toward mass production tends to saturate the small domestic market quite early and allows a firm to expand into new markets by making use of excess capacity and of monopoly profits. One of the reasons why the jaebol issue has become so acute in Korea lies in the nature of the government-business relationship. The Korean government has set economic development as its foremost national goal and, since then, has intervened profoundly in the private sector. Since most strategic industries promoted by the government required a huge capacity in technology, capital and manpower, big firms were favored over smaller firms, and the benefits of industrial policy naturally accrued to large business groups. The concentration of economic power which occured along the way was, therefore, not necessarily a product of the market system. At the same time, the concentration of ownership in business groups has been left largely intact as they have customarily met capital requirements by means of debt. The real advantage enjoyed by large business groups lies in synergy due to multiplant and multiproduct production. Even these effects, however, cannot always be considered socially optimal, as they offer disadvantages to other independent firms-for example, by foreclosing their markets. Moreover their fictitious or artificial advantages only aggravate the popular perception that most business groups have accumulated their wealth at the expense of the general public and under the behest of the government. Since Korea stands now at the threshold of establishing a full-fledged market economy along with political democracy, the phenomenon called the concentration of economic power must be correctly understood and the roles of business groups must be accordingly redefined. In doing so, we would do better to take a closer look at Japan which has experienced a demise of family-controlled Zaibatsu and a success with business groups(Kigyoshudan) whose ownership is dispersed among many firms and ultimately among the general public. The Japanese case cannot be an ideal model, but at least it gives us a good point of departure in that the issue of ownership is at the heart of the matter. In setting the basic direction of public policy aimed at controlling the concentration of economic power, one must harmonize efficiency and equity. Firm size in itself is not a problem, if it is dictated by efficiency considerations and if the firm behaves competitively in the market. As long as entrepreneurship is required for continuous economic growth and there is a discrepancy in entrepreneurial capacity among individuals, a concentration of economic power is bound to take place to some degree. Hence, the most effective way of reducing the inefficiency of business groups may be to impose competitive pressure on their activities. Concurrently, unless the concentration of ownership in business groups is scaled down, the seed of social discontent will still remain. Nevertheless, the dispersion of ownership requires a number of preconditions and, consequently, we must make consistent, long-term efforts on many fronts. We can suggest a long list of policy measures specifically designed to control the concentration of economic power. Whatever the policy may be, however, its intended effects will not be fully realized unless business groups abide by the moral code expected of socially responsible entrepreneurs. This is especially true, since the root of the problem of the excessive concentration of economic power lies outside the issue of efficiency, in problems concerning distribution, equity, and social justice.

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Correlation analysis of radiation therapy position and dose factors for left breast cancer (좌측 유방암의 방사선치료 자세와 선량인자의 상관관계 분석)

  • Jeon, Jaewan;Park, Cheolwoo;Hong, Jongsu;Jin, Seongjin;Kang, Junghun
    • The Journal of Korean Society for Radiation Therapy
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    • v.29 no.1
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    • pp.37-48
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    • 2017
  • Purpose: The most basic conditions of radiation therapy is to prevent unnecessary exposure of normal tissue. The risk factors that are important o evaluate the dose emitted to the lung and heart from radiation therapy for breast cancer. Therefore, comparing the dose factors of a normal tissue according to the radion treatment position and Seeking an effective radiation treatment for breast cancer through the analysis of the correlation relationship. Materials and Methods: Computed tomography was conducted among 30 patients with left breast cancer in supine and prone position. Eclipse Treatment Planning System (Ver.11) was established by computerized treatment planning. Using the DVH compared the incident dose to normal tissue by position. Based on the result, Using the SPSS (ver.18) analyzed the dose in each normal tissue factors and Through the correlation analysis between variables, independent sample test examined the association. Finally The HI, CI value were compared Using the MIRADA RTx (ver. ad 1.6) in the supine, prone position Results: The results of computerized treatment planning of breast cancer in the supine position were V20, $16.5{\pm}2.6%$ and V30, $13.8{\pm}2.2%$ and Mean dose, $779.1{\pm}135.9cGy$ (absolute value). In the prone position it showed in the order $3.1{\pm}2.2%$, $1.8{\pm}1.7%$, $241.4{\pm}138.3cGy$. The prone position showed overall a lower dose. The average radiation dose 537.7 cGy less was exposured. In the case of heart, it showed that V30, $8.1{\pm}2.6%$ and $5.1{\pm}2.5%$, Mean dose, $594.9{\pm}225.3$ and $408{\pm}183.6cGy$ in the order supine, prone position. Results of statistical analysis, Cronbach's Alpha value of reliability analysis index is 0.563. The results of the correlation analysis between variables, position and dose factors of lung is about 0.89 or more, Which means a high correlation. For the heart, on the other hand it is less correlated to V30 (0.488), mean dose (0.418). Finally The results of independent samples t-test, position and dose factors of lung and heart were significantly higher in both the confidence level of 99 %. Conclusion: Radiation therapy is currently being developed state-of-the-art linear accelerator and a variety of treatment plan technology. The basic premise of the development think normal tissue protection around PTV. Of course, if you treat a breast cancer patient is in the prone position it take a lot of time and reproducibility of set-up problems. Nevertheless, As shown in the experiment results it is possible to reduce the dose to enter the lungs and the heart from the prone position. In conclusion, if a sufficient treatment time in the prone position and place correct confirmation will be more effective when the radiation treatment to patient.

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Deep Learning-based Professional Image Interpretation Using Expertise Transplant (전문성 이식을 통한 딥러닝 기반 전문 이미지 해석 방법론)

  • Kim, Taejin;Kim, Namgyu
    • Journal of Intelligence and Information Systems
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    • v.26 no.2
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    • pp.79-104
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    • 2020
  • Recently, as deep learning has attracted attention, the use of deep learning is being considered as a method for solving problems in various fields. In particular, deep learning is known to have excellent performance when applied to applying unstructured data such as text, sound and images, and many studies have proven its effectiveness. Owing to the remarkable development of text and image deep learning technology, interests in image captioning technology and its application is rapidly increasing. Image captioning is a technique that automatically generates relevant captions for a given image by handling both image comprehension and text generation simultaneously. In spite of the high entry barrier of image captioning that analysts should be able to process both image and text data, image captioning has established itself as one of the key fields in the A.I. research owing to its various applicability. In addition, many researches have been conducted to improve the performance of image captioning in various aspects. Recent researches attempt to create advanced captions that can not only describe an image accurately, but also convey the information contained in the image more sophisticatedly. Despite many recent efforts to improve the performance of image captioning, it is difficult to find any researches to interpret images from the perspective of domain experts in each field not from the perspective of the general public. Even for the same image, the part of interests may differ according to the professional field of the person who has encountered the image. Moreover, the way of interpreting and expressing the image also differs according to the level of expertise. The public tends to recognize the image from a holistic and general perspective, that is, from the perspective of identifying the image's constituent objects and their relationships. On the contrary, the domain experts tend to recognize the image by focusing on some specific elements necessary to interpret the given image based on their expertise. It implies that meaningful parts of an image are mutually different depending on viewers' perspective even for the same image. So, image captioning needs to implement this phenomenon. Therefore, in this study, we propose a method to generate captions specialized in each domain for the image by utilizing the expertise of experts in the corresponding domain. Specifically, after performing pre-training on a large amount of general data, the expertise in the field is transplanted through transfer-learning with a small amount of expertise data. However, simple adaption of transfer learning using expertise data may invoke another type of problems. Simultaneous learning with captions of various characteristics may invoke so-called 'inter-observation interference' problem, which make it difficult to perform pure learning of each characteristic point of view. For learning with vast amount of data, most of this interference is self-purified and has little impact on learning results. On the contrary, in the case of fine-tuning where learning is performed on a small amount of data, the impact of such interference on learning can be relatively large. To solve this problem, therefore, we propose a novel 'Character-Independent Transfer-learning' that performs transfer learning independently for each character. In order to confirm the feasibility of the proposed methodology, we performed experiments utilizing the results of pre-training on MSCOCO dataset which is comprised of 120,000 images and about 600,000 general captions. Additionally, according to the advice of an art therapist, about 300 pairs of 'image / expertise captions' were created, and the data was used for the experiments of expertise transplantation. As a result of the experiment, it was confirmed that the caption generated according to the proposed methodology generates captions from the perspective of implanted expertise whereas the caption generated through learning on general data contains a number of contents irrelevant to expertise interpretation. In this paper, we propose a novel approach of specialized image interpretation. To achieve this goal, we present a method to use transfer learning and generate captions specialized in the specific domain. In the future, by applying the proposed methodology to expertise transplant in various fields, we expected that many researches will be actively conducted to solve the problem of lack of expertise data and to improve performance of image captioning.

Analysis of shopping website visit types and shopping pattern (쇼핑 웹사이트 탐색 유형과 방문 패턴 분석)

  • Choi, Kyungbin;Nam, Kihwan
    • Journal of Intelligence and Information Systems
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    • v.25 no.1
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    • pp.85-107
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    • 2019
  • Online consumers browse products belonging to a particular product line or brand for purchase, or simply leave a wide range of navigation without making purchase. The research on the behavior and purchase of online consumers has been steadily progressed, and related services and applications based on behavior data of consumers have been developed in practice. In recent years, customization strategies and recommendation systems of consumers have been utilized due to the development of big data technology, and attempts are being made to optimize users' shopping experience. However, even in such an attempt, it is very unlikely that online consumers will actually be able to visit the website and switch to the purchase stage. This is because online consumers do not just visit the website to purchase products but use and browse the websites differently according to their shopping motives and purposes. Therefore, it is important to analyze various types of visits as well as visits to purchase, which is important for understanding the behaviors of online consumers. In this study, we explored the clustering analysis of session based on click stream data of e-commerce company in order to explain diversity and complexity of search behavior of online consumers and typified search behavior. For the analysis, we converted data points of more than 8 million pages units into visit units' sessions, resulting in a total of over 500,000 website visit sessions. For each visit session, 12 characteristics such as page view, duration, search diversity, and page type concentration were extracted for clustering analysis. Considering the size of the data set, we performed the analysis using the Mini-Batch K-means algorithm, which has advantages in terms of learning speed and efficiency while maintaining the clustering performance similar to that of the clustering algorithm K-means. The most optimized number of clusters was derived from four, and the differences in session unit characteristics and purchasing rates were identified for each cluster. The online consumer visits the website several times and learns about the product and decides the purchase. In order to analyze the purchasing process over several visits of the online consumer, we constructed the visiting sequence data of the consumer based on the navigation patterns in the web site derived clustering analysis. The visit sequence data includes a series of visiting sequences until one purchase is made, and the items constituting one sequence become cluster labels derived from the foregoing. We have separately established a sequence data for consumers who have made purchases and data on visits for consumers who have only explored products without making purchases during the same period of time. And then sequential pattern mining was applied to extract frequent patterns from each sequence data. The minimum support is set to 10%, and frequent patterns consist of a sequence of cluster labels. While there are common derived patterns in both sequence data, there are also frequent patterns derived only from one side of sequence data. We found that the consumers who made purchases through the comparative analysis of the extracted frequent patterns showed the visiting pattern to decide to purchase the product repeatedly while searching for the specific product. The implication of this study is that we analyze the search type of online consumers by using large - scale click stream data and analyze the patterns of them to explain the behavior of purchasing process with data-driven point. Most studies that typology of online consumers have focused on the characteristics of the type and what factors are key in distinguishing that type. In this study, we carried out an analysis to type the behavior of online consumers, and further analyzed what order the types could be organized into one another and become a series of search patterns. In addition, online retailers will be able to try to improve their purchasing conversion through marketing strategies and recommendations for various types of visit and will be able to evaluate the effect of the strategy through changes in consumers' visit patterns.

Adaptability of the high first pod height, shattering-resistant soybean cultivar 'Saegeum' to mechanized harvesting (고착협 내탈립 기계수확 적응 장류·두부용 콩 품종 '새금')

  • Kim, Hyun Tae;Han, Won Young;Lee, Byung Won;Ko, Jong Min;Lee, Yeong Hoon;Baek, In Youl;Yun, Hong Tai;Ha, Tae Joung;Choi, Man Soo;Kang, Beom Kyu;Kim, Hyun Yeong;Seo, Jeong Hyun;Kim, Hong Sik;Shin, Sang Ouk;Oh, Jae Hyun;Kwak, Do Yeon;Seo, Min Jeong;Song, Yoon Ho;Jang, Eun Kyu;Yun, Geon Sik;Kang, Yeong Sik;Lee, Ji Yun;Shin, Jeong Ho;Choi, Kyu Hwan;Kim, Dong Kwan;Yang, Woo Sam
    • Korean Journal of Breeding Science
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    • v.51 no.4
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    • pp.496-503
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    • 2019
  • The soybean cultivar, 'Saegeum', has been developed for preparing soy-paste and tofu. The soybean cultivars 'Daepung' and 'SS98207-3SSD-168' were crossed in 2003 to obtain 'Saegeum'. Single seed descent method was used to advance the generation from F3 to F5, and the plant lines with promising traits were selected from F6 to F7 by pedigree method. The preliminary yield (PYT) and advanced yield trials (AYT) were conducted from 2009 to 2010, and the regional yield trial (RYT) was conducted in 12 regions between 2011 and 2013. The morphological characteristics of 'Saegeum' were as follows: determinate plant type, white flower, tawny pubescence color, and brown pod color. Flowering and maturity dates were August 2, XXXX and October 17, XXXX, respectively. Plant height, first pod height, number of nodes, number of branches, and number of pods were 79 cm, 18 cm, 16, 2.3, and 44, respectively. The seed characteristics of 'Saegeum' were as follows: yellow spherical shape, yellow hilum, and the 100-seed weight was 25.4 g. 'Saegeum' was resistant to bacterial pustule and SMV in the field test, and its lodging resistance was mildly strong, whereas its shattering resistance was excellent. The ability of this cultivar to be processed into tofu, soybean malt, and other fermented products was comparable with that of 'Daewonkong'. The yield of 'Saegeum' in the adaptable regions was 3.02 ton ha-1. Thus, 'Saegeum' is adaptable to mechanized harvesting because of its high first pod height, as well as lodging and shattering resistance. (Registration number: 5929)

Temperature-Programmed Reduction of Copper Oxide Supported on ${\gamma}-Al_2O_3$ and $SiO_2$ (${\gamma}-Al_2O_3$$SiO_2$에 입혀진 산화 구리의 승온 환원)

  • Hwa-Gyung Lee;Chong-Soo Han;Min-Soo Cho;Kae-Soo Lee;Hakze Chon
    • Journal of the Korean Chemical Society
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    • v.30 no.5
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    • pp.415-422
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    • 1986
  • The metal-support interaction of copper oxide supported on ${\gamma}$-alumina and silica was studied by X-ray diffraction (XRD) and temperature-programmed reduction(TPR). It was found that XRD pattern of CuO can not be observed up to 5.0wt % copper content for CuO/${\gamma}-Al_2O_3$ while CuO/$SiO_2$ sample shows the CuO pattern even at 2.5wt% copper content. $H_2-$TPR of CuO/${\gamma}-Al_2O_3$ system shows four major peaks at 145${\circ}C$, 185${\circ}C$, 210${\circ}C$, and 250${\circ}C$. In the case of CuO/$SiO_2$, a large peak at 250${\circ}C$ was appeared accompanying a small peak at 425${\circ}C$. Comparing the TPR peaks with that of copper aluminate which was prepared from the calcination of CuO/${\gamma}-Al_2O_3$ at 1000${\circ}C$, the peaks at around 145${\circ}C$, 200${\circ}C$ (185${\circ}C$ and 210${\circ}C$), and 250${\circ}C$ were corresponded to $Cu^+$ ion in CuO interacting ${\gamma}-Al_2O_3$, $Cu^+$ ions in defect sites of ${\gamma}-Al_2O_3$ and $Cu^{2+}$ ion in the bulk CuO layer, respectively. From the results, it was concluded that there is considerable metal-support interaction in CuO on ${\gamma}-Al_2O_3$ and the interaction results in a stabilization of $Cu^+$ ion in the system.

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Some Tertiary Interactions in 5S rRNA from Xanthomonas celebensis (Xanthomonas celebensis 5S rRNA의 몇 가지 삼차상호작용)

  • Bongrae Cho;Yeonghoon Lee;Myung-Un Choi;Inwon Park
    • Journal of the Korean Chemical Society
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    • v.37 no.2
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    • pp.237-243
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    • 1993
  • The primary and secondary structure of the 5S rRNA isolated from Xanthomonas celebensis were determined by enzymatic and chemical degradation methods. It consists of 119 nucleotides and contains no modified nucleosides. As with the 5S rRNAs of X. maltophilia and X. citri, it contains an additional uridine residue on the 5'-terminus. Its secondary structure was almost identical to the models previously proposed by us for the 5S rRNA of two Xanthomonas species. Its secondary structure consists of five helices, five loops and two bulges. The tertiary interactions in the 5S rRNA molecule were analyzed by Fe(II)-EDTA treatment and hybridization method using deoxyhexamer. From the fact that some adenine residues in loop M, region $I_1-C$, loop $H_1$, and loop $H_2$ become susceptible to diethylpyrocarbonate when the 5S rRNA was hybridized with deoxyhexamer complementary to the sequence $U_{35}CCCAU_{40}$ and that some nucleotide residues in loop M, loop $H_1$ and region $D-I_2$ become resistant Fe(II)-EDTA cleavage in the presence of $Mg^{2+}$, it is presumed that loops $H_1$ and $H_2$ interact with loop M in some way. In the tertiary interaction, the regions $I_1-C$ and $D-I_2$ seem to act as hinges in folding the stems $B-I_1-C$ and $D-I_2-E.$ It was found that loop $H_1$ changes into a smaller loop of three bases by forming noncanonical A : C base-pairs ih acidic environment.

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Design of a pilot-scale helium heating system to support the SI cycle (파이롯 규모 SI 공정 시험 설비에서의 헬륨 가열 장치 설계)

  • Jang, Se-Hyun;Choi, Yong-Suk;Lee, Ki-Young;Shin, Young-Joon;Lee, Tae-Hoon;Kim, Jong-Ho;Yoon, Seok-Hun;Choi, Jae-Hyuk
    • Journal of Advanced Marine Engineering and Technology
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    • v.40 no.3
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    • pp.157-164
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    • 2016
  • In this study, researchers performed preliminary design and numerical analysis for a pilot-scale helium heating system intended to support full-scale construction for a sulfur-iodine (SI) cycle. The helium heat exchanger used a liquefied petroleum gas (LPG) combustor. Exhaust gas velocity at the heat exchanger outlet was approximately 40 m/s based on computational thermal and flow analysis. The maximum gas temperature was reached with six baffles in the design; lower gas temperatures were observed with four baffles. The amount of heat transfer was also higher with six baffles. Installation of additional baffles may reduce fuel costs because of the reduced LPG exhausted to the heat exchanger. However, additional baffles may also increase the pressure difference between the exchanger's inlet and outlet. Therefore, it is important to find the optimum number of baffles. Structural analysis, followed by thermal and flow analysis, indicated a 3.86 mm thermal expansion at the middle of the shell and tube type heat exchanger when both ends were supported. Structural analysis conditions included a helium flow rate of 3.729 mol/s and a helium outlet temperature of $910^{\circ}C$. An exhaust gas temperature of $1300^{\circ}C$ and an exhaust gas rate of 52 g/s were confirmed to achieve the helium outlet temperature of $910^{\circ}C$ with an exchanger inlet temperature of $135^{\circ}C$ in an LPG-fueled helium heating system.