• Journal of Electrical Engineering and Technology
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• v.8 no.6
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• pp.1512-1519
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• 2013

Oil-impregnated paper is a major type of insulation used in oil-filled converter transformers for both traditional and new energy systems. This paper presents and analyzes the results of the experiment conducted on the electrical aging of oil-impregnated paper under AC-DC combined voltages using the pulsed electro-acoustic (PEA) technique. The formation and dynamics of space charge affected the performance of insulation material. The electrical aged oil-paper insulation was obtained through electrical aged experiments under the voltages. Based on the PEA technique, measurements were carried out when the oil-paper insulation system was subjected to different stressing and aging times. The space charge dynamics in the bulk of the oil-paper insulation system with different aging times were measured and analyzed. Characteristic parameters such as the total charge injection amount, the total charges of fast moving and slow moving, and the distortion factor of electric field were calculated and discussed. Results show that the longer electrical aging time, the more charges trapped in the bulk of aging sample. It leads to larger distortion factor of electric field in the bulk of aging samples and accelerate degradation of oil-paper insulation under AC-DC combined voltages.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.10
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• pp.1471-1478
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• 2010

Microforming processes have recently attracted considerable attention from industry and academia since they enable the production of microscale parts using various materials at a high production rate, minimize material loss, and provide parts with excellent mechanical properties. However, for successful development and applications of the microforming process it is critical to take the tribological size effect into consideration because previous studies have shown that traditional friction models for macroscale forming generate significantly erroneous results in the case of microforming. In this paper, we performed scaled ring compression experiments to investigate the tribological size effect of aluminum and brass materials in microforming. The sensitivity of the interfacial friction to the deformation characteristics of the ring was quantitatively analyzed by the finite element analysis. In addition, a friction model based on slip line field and upper boundary techniques was used to theoretically explain the friction mechanism in microforming.

• Korean Journal of Pharmacognosy
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• v.40 no.4
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• pp.298-302
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• 2009

Samultang is one of traditional medicine composed of Paeonia lactiflora, Angelica gigas, Rehmannia glutinosa and Cnidium officinale. To develop simultaneous determination of paeoniflorin, decursin and 5-HMF in Samultang, a high performance liquid chromatography with diode array detector was used. To separate three marker components, Dionex $C_{18}$ column (5 ${\mu}m$, 120 ${\AA}$, 4.6 mm${\times}$150 mm) was used with a gradient elution system of water and methanol. UV wavelength of detector set at 230 nm and 280 nm. This method was validated by linearity, precision test and recovery test. Calibration curves of three standard components were showed good linear regression ($R^2$>0.9973). LOD and LOQ ranged from 0.08 ${\mu}g$/ml to 0.38 ${\mu}g$/ml and 0.25 ${\mu}g$/ml to 1.16 ${\mu}g$/ml, respectively. The relative standard deviations (RSDs) of data of the inter-day and intra-day experiments were less than 0.54% and 0.89%, respectively. The measured results of recovery test were varied from 93.36 to 107.79 with RSD values 0.01~1.45%. The established method was applied for separation of bio-conversion Samultang sample and compared with control sample.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.5
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• pp.369-376
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• 2014

This paper presents a method that integrates passive and active-sensing techniques for the structural health monitoring of plate-like structures. Three piezoelectric transducers are deployed in a L-shape to detect and locate an impact event by measuring and processing the acoustic emission data. The same sensor arrays are used to estimate the subsequent structural damage using guided waves. Because this method does not require a prior knowledge of the structural parameters, such as the wave velocity profile in various directions, accurate results could be achieved even on anisotropic or curved plates. A series of experiments was performed on plates, including a spar-wing structure, to demonstrate the capability of the proposed method. The performance was also compared to that of traditional approaches and the superior capability of the proposed method was experimentally demonstrated.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.2
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• pp.436-439
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• 2004

Mubigangjang-Ju (MGJ) is a traditional wine, fermented extract of Cynanchum wilfordii, Angelicae gigantis and Epimedium koreanum etc. In the present study, we comparatively investigated the immune-enhancing effect of fermented extract (MGJ) and water extract (WE). Forced swimming test (FST) was performed as a model of activity test in mice and measured blood urea nitrogen (BUN), aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactic dehydrogenase (LDH), glucose (Glc) and total protein (TP) in the serum. Each extracts were orally administered into mice, 10 ㎖/kg, once per day for 7 days using a feeding atraumatic needle. After 3 days, on FST, the immobility time was decreased in the MGJ-fed group (133.7±18.6 s) in comparison with the saline-fed group (155.8±16.6 s). After 7 days, the immobility time was significantly decreased in the MGJ-fed group (105.3±12.7 s) in comparison with the saline-fed group (171.3±8.1 s). In addition, the content of AST was significantly decreased and the contents of BUN, ALT and LDH in the blood serum was also decreased. Whereas, the content of Glc tend to increase and TP level was not changed. However, WE had no effect on all experiments. The present results suggest that fermented extract was more effective than water extract and it may be useful for the immune-enhancing agent.

• Journal of the Korean Wood Science and Technology
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• v.41 no.4
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• pp.269-275
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• 2013

Antifungal and insecticidal activity of Korean traditional medicinal plants was carried out to develop natural material for the development of organic cultural heritage conservation. As a result, Phellodendron amurense fruit was finally selected as a candidate of antifungal and insecticidal natural material. An novel active compound was purified from the ethylacetate fraction of Phellodendron amurense fruits using silica gel and Sephadex LH-20 column chromatography and PTLC. The compound was obtained as yellow oil form; UV ${\lambda}_{max}$(MeOH): 260 nm. The chemical structure of novel compound was determined as (4'-ethyl-2'-methylfuranyl)-6-methoxy-7-methylnona-2E,4E,6Z,8E-tetraenoic acid on the basis of various NMR experiments including $^1H$- and $^{13}C$-NMR, HMQC, HMBC and ESI-mass spectrum.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.498-498
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• 2013

Atmospheric Pressure Plasmas have pioneered a new field of plasma for biomedical application bridging plasma physics and biology. Biological and medical applications of plasmas have attracted considerable attention due to promising applications in medicine such as electro-surgery, dentistry, skin care and sterilization of heat-sensitive medical instruments [1]. Traditional approaches using electronic devices have limits in heating, high voltage shock, and high current shock for patients. It is a great demand for plasma medical industrial acceptance that the plasma generation device should be compact, inexpensive, and safe for patients. Microwave-excited micro-plasma has the highest feasibility compared with other types of plasma sources since it has the advantages of low power, low voltage, safety from high-voltage shock, electromagnetic compatibility, and long lifetime due to the low energy of striking ions [2]. Recent experiment [2] shows three-log reduction within 180-s treatment of S. mutans with a low-power palm-size microwave power module for biomedical application. Experiments using microwave plasma are discussed. This low-power palm-size microwave power module board includes a power amplifier (PA) chip, a phase locked loop (PLL) chip, and an impedance matching network. As it has been a success, more compact-size module is needed for the portability of microwave devices and for the various medical applications of microwave plasma source. For the plasma generator, a 1.35-GHz coaxial transmission line resonator (CTLR) [3] is used. The way of reducing the size and enhancing the performances of the module is examined.

• Journal of Microbiology and Biotechnology
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• v.26 no.9
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• pp.1517-1526
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• 2016

Lactic acid bacteria (LAB) isolated from fermented foods have potential as a treatment for immune-related disorders and the use of LAB has been increasing worldwide. In this study, the differential cytokine regulatory effect was examined with three isolates of lactobacilli strains; namely, Lactobacillus plantarum K55-5 isolated from dairy product, and L. sakei K101 and L. plantarum K8 previously isolated from kimchi (a Korean traditional fermented vegetable). Production of cytokines such as IL-10, IL-12, IFN-γ, and TNF-α was significantly increased in L. sakei K101- and L. plantarum K55-5-treated splenocytes as compared with controls. The oral administration of L. sakei K101 and L. plantarum K55-5 increased cytokine production in the immunosuppressed mouse splenocytes and blood. NK cell cytotoxic activity was also increased in L. sakei K101- and L. plantarum K55-5-fed mice. On the other hand, L. plantarum K8 did not affect cytokine induction in all the experiments performed in this study. The cytokine-inducing effect of L. plantarum K55-5 was significantly increased by lysates of heat-killed bacteria as compared with live, heat-killed, or supernatant of cell lysates. TNF-α production by lipoteichoic acids (LTAs) isolated from the three isolates of lactobacilli was compared, and it was found that K55-5 LTA had a highest cytokine-inducing ability, which was mediated by TLR2-mediated NF-κB and ERK activation. Taken together, our study suggests that L. plantarum K55-5 and L. sakei K101 can be used for the treatment of immunosuppressed disorders.

• Journal of the Korean Society for information Management
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• v.21 no.2
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• pp.189-210
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• 2004

The purpose of this study is to evaluate the performance of XML retrieval based on ORDBMSs(Object-Relational Database Management Systems) approach. This paper describes indexing and retrieval methods for XML documents and the methodologies of experiments at INEX(Initiative for the Evaluation of XML retrieval). Like any other traditional information retrieval experiment, the test collection was consists of documents, topics/queries, task, relevance assessments and evaluation. EXIMA$^{TM}$ Supply, a kind of native XML DB based on ORDBMS technologies, is used for this experiment. Although this approach has many benefits, for example, no delay in storing and searching XML documents. but it showed relatively disappointed retrieval performance at INEX 2002. This result may caused since the given topics had to be decomposed and modified to be processed by the XPath processor, and during this modification the original meaning of topics can be changed inevitably and some important information nay pass over.r.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.42 no.4
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• pp.210-216
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• 2006

The circle hook experiments were conducted to compare the catch rates of target and bycatch species between J hook and circle hooks in the tuna longline fishery of the eastern Pacific Ocean between $1^{\circ}48'S-7^{\circ}00'S\;and\;142^{\circ}00'-149^{\circ}13'W$ from July 15 to August 12, 2005. In the target species group no significant differences among 3 types hook, between size 4.0 traditional tuna hooks(J-4) and size 15 circle hooks(C15), and between C15 and size 18 circle hooks(C18) were revealed, but significant differences were found between J-4 and C18. In the bycatch species group significant differences were found among 3 types hook, between J 4 and C15, and between J-4 and C18, but no significant differences were revealed between C15 and C18. Large circle hook(C18) had the lowest catch rate for tunas and for other fishes, and the small circle hook(C15) had lowest rate for billfishes and sharks. The length distributions for bigeye tuna are very similar for the 3 hook types. There were very slight differences in length size between hook types in the bycatch species.