• Journal of Science and Technology Studies
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• v.10 no.2
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• pp.37-76
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• 2010

Park Tae-Joon, a pioneer in the Korean steel industry, has greatly influenced the advancement of science and technology as well as the development of the nation's economy. He believed that POSCO, which was a government-owned company, should not only focus on making profits, but also operate for higher state-level purposes. This belief became the basis for founding a general laboratory and a research university, as well as building big science and technology R&D facilities. Park Tae-Joon's efforts to establish a research university and his dedication to the advancement of science education stemmed from his devotion to public welfare. Just like he believed that the steel industry, which is the basis for all other industries, should be promoted at the state-level, he believed that university and basic science should also be promoted at the state-level. Thanks to his philosophy, the Pohang University of Science and Technology has risen beyond just a polytechnic school to become a research university that makes revolutionary science and technology advancements for the nation. The fact that Park Tae-Joon used profits from business to build the university and national research facilities such as the Pohang Light Source also shows that he nurtured pure science with the welfare of the whole nation in mind.

• Textile Coloration and Finishing
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• v.28 no.4
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• pp.231-238
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• 2016

We investigated the evolution of crystal formation as a function of drawing ratio in poly(1,4-diaminobutane-co-adipic acid-co-${\varepsilon}$-caprolactam-co-diethylenetriamine)(nylon 466T) copolymer formed by four monomers, i.e 1,4-diaminobutane, adipic acid, ${\varepsilon}$-caprolactam, diethylenetriamine(DETA), using synchrotron X-ray scattering measurement. In case of pristine(as spun) nylon 466T fiber, it was consisted with unoriented nylon $6{\alpha}$ and unoriented nylon $46{\alpha}$ phases. As increase the drawing ratio, unoriented nylon $6{\alpha}$ was transformed to oriented ${\gamma}$ phase, while unoriented nylon $46{\alpha}$ changed to oriented $46{\alpha}$ phase. The effect of the addition of DETA was not observed in the pristine fibers. However, DETA affected to restrict the formation of crystals at the maximum drawing condition, and as a result it had a role to increase the moisture regain.

• Molecules and Cells
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• v.43 no.5
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• pp.479-490
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• 2020

Interleukin-9 (IL-9) is well known for its role in allergic inflammation. For cancer, both pro- and anti-tumor effects of IL-9 were controversially reported, but the impact of IL-9 on tumor metastasis has not yet been clarified. In this study, IL-9 was expressed as a secretory form (sIL-9) and a membrane-bound form (mbIL-9) on B16F10 melanoma cells. The mbIL-9 was engineered as a chimeric protein with the transmembrane and cytoplasmic region of TNF-α. The effect of either mbIL-9 or sIL-9 expressing cells were analyzed on the metastasis capability of the cancer cells. After three weeks of tumor implantation into C57BL/6 mice through the tail vein, the number of tumor modules in lungs injected with IL-9 expressing B16F10 was 5-fold less than that of control groups. The percentages of CD4⁺ T cells, CD8⁺ T cells, NK cells, and M1 macrophages considerably increased in the lungs of the mice injected with IL-9 expressing cells. Among them, the M1 macrophage subset was the most significantly enhanced. Furthermore, peritoneal macrophages, which were stimulated with either sIL-9 or mbIL-9 expressing transfectant, exerted higher anti-tumor cytotoxicity compared with that of the mock control. The IL-9-stimulated peritoneal macrophages were highly polarized to M1 phenotype. Stimulation of RAW264.7 macrophages with sIL-9 or mbIL-9 expressing cells also significantly increased the cytotoxicity of those macrophages against wild-type B16F10 cells. These results clearly demonstrate that IL-9 can induce an anti-metastasis effect by enhancing the polarization and proliferation of M1 macrophages.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.3
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• pp.279-289
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• 2018

N-nitrosodimethylamine (NDMA) is a class of disinfection byproducts and a frequently detected nitrosamine with carcinogenic potentials. This review summarizes NDMA precursors, their formation mechanisms in chloraminated water, and mitigation strategies. Understanding the formation mechanism and characteristics of precursors is essential for developing a mitigation strategy. Dimethylamine (DMA), the most widely studied NDMA precursor, has an NDMA molar yield up to 3%. In comparison, a subset of tertiary amines, e.g., pharmaceuticals, generate up to 90% upon chloramination. Potent NDMA precursors, are characterized by their negative partial charge, low planarity values and molecular weight, and high bond length and $pK_a$ values. A nucleophilic substitution of tertiary amine on chloramine is a key reason for the high NDMA yield from the most potent NDMA precursors. The distribution and fate of NDMA in surface water, aquifers, and its formation in the distribution system can be mitigated through two strategies: (1) degrading or/removing NDMA after its formation and (2) pre-treatment of its precursor's prior chloramination.

• Journal of KIISE
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• v.44 no.1
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• pp.57-62
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• 2017

Traditional Korean morphological analysis and POS tagging methods usually consist of two steps: 1 Generat hypotheses of all possible combinations of morphemes for given input, 2 Perform POS tagging search optimal result. require additional resource dictionaries and step could error to the step. In this paper, we tried to solve this problem end-to-end fashion using sequence-to-sequence model convolutional features. Experiment results Sejong corpus sour approach achieved 97.15% F1-score on morpheme level, 95.33% and 60.62% precision on word and sentence level, respectively; s96.91% F1-score on morpheme level, 95.40% and 60.62% precision on word and sentence level, respectively.

• Journal of Korean Library and Information Science Society
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• v.21
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• pp.253-289
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• 1994

The purpose of this study is about the search pattern of LINNET (Library Information Network System) OPAC users by transaction log, maintained by POSTECH(Pohang University of Science and Technology) Central Library, to provide feedback information of OPAC system design. The results of this study are as follows. First, for the period of this analysis, there were totally 11, 218 log-ins, 40, 627 transaction logs and 3.62 retrievals per a log-in. Title keyword was the most frequently used, but accession number, bibliographic control number or call number was very infrequently used. Second, 47.02% of OPAC, searches resulted in zero retrievals. Bibliographic control number was the least successful search. User displayed 2.01% full information and 64.27% local information per full information. Third, special or advanced retrieval features are very infrequently used. Only 22.67% of the searches used right truncation and 0.71% used the qualifier. Only 1 boolean operator was used in every 22 retrievals. The most frequently used operator is 'and (&)' with title keywords. But 'bibliographical control number (N) and accessionnumber (R) are not used at all with any operators. The causes of search failure are as follows. 1. The item was not used in the database. (15, 764 times : 79.42%). 2. The wrong search key was used. (3, 761 times : 18.95%) 3. The senseless string (garbage) was entered. (324 times : 1.63%) On the basis of these results, some recommendations are suggested to improve the search success rate as follows. First, a n.0, ppropriate user education and online help function let users retrieve LINNET OPAC more efficiently. Second, several corrections of retrieval software will decrease the search failure rate. Third, system offers right truncation by default to every search term. This methods will increase success rate but should considered carefully. By a n.0, pplying this method, the number of hit can be overnumbered, and system overhead can be occurred. Fourth, system offers special boolean operator by default to every keyword retrieval when user enters more than two words at a time. Fifth, system assists searchers to overcome the wrong typing of selecting key by automatic korean/english mode change.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.1
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• pp.40-46
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• 2007

A laboratory scale experiment on phenol conversion properties by pulsed corona discharge process was carried out. Effects of operating parameters such as applied voltage, input oxygen, and electrode geometry on phenol conversion and solution properties were investigated. Electrical discharges generated in liquid phase increased the liquid temperature by heat transfer from current flow, decreased the pH value by producing various organic acids from phenol degradation, and increased conductivity by generating charge carriers and organic acids. The oxygen supply enhanced the phenol conversion through the ozone generation dissolution and the production of OH radicals. Series type electrode configuration induced more ozone production than reference type configuration because it produced gas phase discharges as well as liquid phase discharges. Therefore, the higher phenol conversion and TOC(total organic carbon) removal efficiency were obtained in series type configuration.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.5
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• pp.626-630
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• 2010

Since the paper plagiarism has become one of important social issues, it is necessary to develop system for measuring the similarity between papers. The speed and accuracy of the system are very important features. So many researchers are studying the features. In this paper, we propose a preprocessing method using 'Global Dictionary' model to enhance performance of the system. The global dictionary includes information of all words in the document repository. The system uses the model to find similar papers with low computing time. Finally our experiment showed that a set of more than 20,000 documents could be reduced to about 50 documents drastically by our filtering techniques, which proves the excellence of our system.

• Journal of the Korean Vacuum Society
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• v.15 no.5
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• pp.485-492
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• 2006

Two new copper(I) complexes with organic ligands, $[Cu^I(hfac)]_2(DVTMSO)$ and $[Cu^I(hfac)]_2(HD)$ (hfac=hexafluoroacetylacetonate, DVTMSO=1,2-divinylte-tramethyl-disiloxane, HD=1,5-hexadiene) were synthesized and used for copper metal-organic chemical vapor deposition. In these compounds, two Cu(hfac) fragments are bonded by one neutral ligand forming unusual structure with respect to other Cu(I) complexes. The compounds exhibited relatively high volatility and stability when compared to other copper(I) precursors. By using the reported compounds as precursors, a continuous Cu layer was not formed but the Cu islands were only observed. And the shape and size of Cu islands are significantly changed as a function of the substrate temperature.

• The Journal of the Acoustical Society of Korea
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• v.39 no.2
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• pp.87-97
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• 2020

In this paper, the design of piezoelectric Micro-machined Ultrasonic Transducer (pMUT) for wideband ultrasonic radiation in air was investigated. One of the methods to achieve wide frequency bandwidth in single device is modeling the transducer to multi-resonance system. The new pMUT was designed as a multi-resonance system with the addition of a suitable acoustic structure to the front and back of a thin film structure. A new pMUT consisting of thin film parts, radiation parts, and packaging parts is designed with a Lumped Parameter Model (L.P.M). Finally, it was validated as a Finite Element Method (FEM) simulation. The final designed pMUT achieved a frequency band of 102 kHz ~ 132 kHz (-3 dB).