• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.11 no.5
• /
• pp.60-67
• /
• 2012

In the study, the effect grinding condition on the workpiece arithmetical average roughness(Ra) to 10 steps leading to cutting each section with the spindle rotational speed 8000rpm and feed rate 150mm/min of grinding in GC(green silicon carbide) grinding processing after heat treatment and non heat treatment of SCM415 material. Also the following conclusions were obtained analysis of stress distribution displacement and finite elements method(FEM) on assemble parts with 3+2 axis simultaneous control through grinding and gave a load 11kg on ATC arm both sides gave a load of 11kg. For the centerline average roughness(Ra) in the heat and non-heat treatment work pieces, which were appeared the most favorable in the fifth section were $0.511{\mu}m$ and $0.514{\mu}m$, that were shown in the near the straight line section was the smallest deformation of curve. In addition, the bad surface roughness appeared on the path is too long by changing angle, the more inclined depth of cut, because the chip discharging is not smoothly.

• Journal of Korean Society for Atmospheric Environment
• /
• v.27 no.6
• /
• pp.734-745
• /
• 2011

In this article, we reviewed the monitoring status of hazardous VOC in ambinet air in Korea and some developed countries such as USA, Japan, and UK. In many countries, two types of VOC monitoring stations are being operated, i.e., for hazardous VOC and photochemical VOC. Each country has different target VOC but all includes benzene. Korea, Japan, and UK have a national ambient air quality standard for benzene, but no national standard has been established in the USA. For sampling of the hazardous VOC, the adsorbent method is adopted in Korea and UK, while the canister method is used in the USA. Both of adsorbent and canister methods are used in Japan. USA and UK have only non-automatic method to measure the hazardous VOC, and the individual samples are being sent to their national laboratories for integrated analysis. On the other hand, Korea and Japan have automatic and nonautomatic methods to measure the hazardous VOC. Local governments or regional environmental agencies in Korea and Japan have the authorization for the sampling and analysis of VOC. According to a field study to evaluate the performance of automatic VOC monitoring system, controlling the moisture in the air sample was identified as the most important problem. However, careful attention must be given to using a moisture removing device such as Nafyon dryer, because of unexpected artifacts formation. In order to have reliable data, it is highly recommended not only to use internal standards, but to use appropriate hydrophobic adsorbents as a cold trap in any automatic on-line VOC monitoring system.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.2
• /
• pp.945-950
• /
• 2014

Purpose: To explore the value of systemic inflammatory markers as independent prognostic factors and the extent these markers improve prognostic classification for patients with inoperable advanced or metastatic gastric cancer (GC) receiving palliative chemotherapy. Methods: We studied the prognostic value of systemic inflammatory factors such as circulating white blood cell count and its components as well as that combined to form inflammation-based prognostic scores (Glasgow Prognostic Score (GPS), Neutrophil-Lymphocyte Ratio (NLR), Platelet Lymphocyte Ratio (PLR), Prognostic Index (PI) and Prognostic Nutritional Index (PNI)) in 384 patients with inoperable advanced or metastatic gastric cancer (GC) receiving first-line chemotherapy. Univariate and multivariate analyses were performed to examine the impact of inflammatory markers on overall survival (OS). Results: Univariate analysis revealed that an elevated white blood cell, neutrophil and/or platelet count, a decreased lymphocyte count, a low serum albumin concentration, and high CRP concentration, as well as elevated NLR/PLR, GPS, PI, PNI were significant predictors of shorter OS. Multivariate analysis demonstrated that only elevated neutrophil count (HR 3.696, p=0.003) and higher GPS (HR 1.621, p=0.01) were independent predictors of poor OS. Conclusion: This study demonstrated elevated pretreatment neutrophil count and high GPS to be independent predictors of shorter OS in inoperable advanced or metastatic GC patients treated with first-line chemotherapy. Upon validation of these data in independent studies, stratification of patients using these markers in future clinical trials is recommended.

• Journal of the Korean Institute of Gas
• /
• v.28 no.3
• /
• pp.60-69
• /
• 2024

This study aims to evaluate the measurement accuracy of on-line natural gas analyzers operated to measure the quality of natural gas at gas supply points in Korea and verify the validity of the calorific value results used in gas trading after the implementation of the energy content-based national gas trading system in 2012. The measurement accuracy of the gas analyzers has been evaluated annually since 2013 through proficiency testing conducted by interlaboratory comparison. All test results were analyzed statistically to verify the measurement management capability and reliability of the measurement results of the gas analyzers for custody transfer. The evaluation results showed that in most tests, the concentration of individual components and calorific values satisfied the evaluation criteria according to ISO 13528 and ISO/TR 14749, demonstrating statistical agreement with the reference testing. It was confirmed that the measurement accuracy was appropriately maintained within the theoretically possible limits through systematic performance management, ensuring the reliability of calorific value measurements used in natural gas transactions.

• Food Science and Biotechnology
• /
• v.17 no.5
• /
• pp.1086-1091
• /
• 2008

The antioxidant activities of the extracts of dangyuja (Citrus grandis Osbeck) leaves were evaluated. The highest phenolic content was obtained from the ethyl acetate fraction (EF) (202.1$\pm$0.8 mg GAE/g dried extract) and it exhibited the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity. The cytoprotective effects of EF on oxidative damage induced by tert-butyl hydroperoxide (t-BHP) in a human hepatoma cell line, HepG2 cells, were investigated to understand the intracellular antioxidant mechanisms. Treatment of HepG2 cells with EF prior to oxidative stress was found to inhibit reactive oxygen species (ROS) generation, lipid peroxidation, and DNA damage in a dose-dependent manner. Gas chromatography-mass spectrometry (GC-MS) studies on EF resulted in tentative identification of 19 compounds representing 94.3% of the total content. Taken together, these results demonstrated that EF has excellent antioxidant activities and thus dangyuja leaves have great potential as a source for natural antioxidant which can be applied in food products.

• Journal of Korean Society for Atmospheric Environment
• /
• v.19 no.5
• /
• pp.491-502
• /
• 2003

In the present work, the distribution characteristics of ambient volatile organic compounds (VOCs) were investigated at high temporal resolution from a monitoring station located in a mid-eastern area of Seoul. A total number of 587 samples were collected during December 2002 to January 2003. The measurements of VOC were conducted by a combination of on-line air sampling and thermal desorption unit (TDU) coupled with capillary GC/FID analysis. A total of five aromatic compounds (BTEX: benzene, toluene, ethylbenzene, m, p-xylene, and o-xylene) were measured routinely at hourly intervals during the whole study period. The mean concentrations of BTEX measured in our study period were found in the order: toluene (8.99 $\pm$5.38 ppb) > benzene (0.92$\pm$0.52 ppb) > m, p-xylene (0.51$\pm$0.34 ppb) > 0- xylene (0.48$\pm$0.35 ppb) > ethyl benzene (0.43$\pm$ 0.32 ppb). The BTEX concentrations were generally higher during the daytime than the nighttime, exhibiting certain patterns on a weekly basis. Results of our analysis indicate that the unusually high concentrations of toluene, while showing good correlations with other VOCs, can be a good indicator of air pollution in the study area.

• Journal of Food Hygiene and Safety
• /
• v.16 no.3
• /
• pp.232-240
• /
• 2001

One hundred twenty five bacterial isolates were obtained from the brown blotch-diseased oyster mushrooms collected from markets. Among them, 45 were determined as pathogenic bacteria and white line forming organisms(WLFO) were 6 strains and white line reaction organisms (WLRO) were 6 strains. All of the white line forming isolates were identified as Pseudomonas tolaasii which is a known pathogen of brown blotch disease of oyster mushroom by GC-MIS(Gas chromatography-microbial identification system). Six of the white line reacting organisms were identified as P. chlomraphis, P. fluorescens biotype A and type C. The rest of them were P gingeri, P. agarici, P. fluorescens biotype B, P. chloroyaphis, non-pathogenic P. tolaasii, P. putida biotype A and B etc. For spectrum of activity of tolaasin, culture filtrates from pathogenic isolates were examined by browning of mushroom tissue and pitting of mushroom caps. The weak pathogenic bacteria didn't induce browning or pitting of mushroom tissue. On the other hand, strong pathogenic isolates showed browning and pitting reaction on mushroom. An extracellular toxin produced by P. tolaasii, was investigated. The hemolysis activity test of 6 strains identified as P. tolaasii were 0.8∼0.9 at 600 nm and 3 strains of WLRO were 0.9∼1.0 and Pseudomonas app. were 1.0∼1.2. Observation of fresh mushroom tissue using confocal laser scanning microscopy was carried out for images of optical sectioning and vertical sectioning. Also images of brown blotch diseased oyster mushroom tissue after contamination P. tolaasii was obtained by CLSM.

• Journal of Life Science
• /
• v.30 no.11
• /
• pp.973-982
• /
• 2020

In this study, we examined inhibition of adipocyte differentiation associated with the administration of camphor, a substance identified in extracts of the flowering plant Chrysanthemum indicum L. (CI). No camphor-mediated cytotoxicity was observed over a period of 1-10 days in studies targeting cells of the 3T3-L1 adipocyte-like line. Experiments that featured siRNA-mediated suppression of the transmembrane proteins Patched (PTCH) and Smoothened (SMO) resulted in inhibition and activation of differentiation, respectively. Interestingly, inhibition of PTCH typically activates SMO protein targeting and serves to activate hedgehog (HH)-mediated signaling. The results of our study suggest that activation of HH-mediated signaling can inhibit adipocyte differentiation. Furthermore, expression of glioma-associated oncogene homologue 1 (Gli1) was detected by flow cytometry in 62.7±1.5% of cells in response to administration of Lactobacillus rhamnosus (KCTC 3237) and in 60.4±2.2% of cells in response to camphor; these levels are higher than those detected in undifferentiated controls (24.9±3.1%). No change in the state of fermented camphor was identified by gas chromatography-mass spectrometry (GC-MS), but a 15.41% quantitative increase was confirmed in KCTC 3237. Overall, we conclude that administration of camphor resulted in overexpression of SMO and modulated the differential expression of Gli1. Animal studies focused on the impact of camphor as an agent to counteract obesity might be considered in the future. Indeed, camphor and similar physiologically active compounds from fermented CI might be developed as new and effective treatments for obesity.

• KEPCO Journal on Electric Power and Energy
• /
• v.5 no.4
• /
• pp.263-273
• /
• 2019

South Korea's OF cable is reaching its expected design life of 30 years, and as a result, the risk of failure is increasing. Therefore, it is necessary to diagnose the long-term operating OF cables through accurate diagnosis at the right time to prevent the failure. Currently, the KEPCO periodically conducts DGA. However, the gas found in DGA is caused by oil deterioration as well as insulation paper. Therefore, the analysis of the degree of polymerization and furan compounds which is an evaluation of insulation paper considered to be the life of OF cables is required. In addition, the results of the evaluation of deterioration of insulation paper need to be checked for correlation with the results of DGA. In this study, DGA carried out through GC, the degree of polymerization was analyzed using an automatic viscometer, and HPLC was used to detect the furan compounds. In addition, the obtained results were applied to the SVM technique, which was recently introduced to determine abnormalities in OF cable. And the results which were accurate and reliable were obtained.

• Journal of the Korean Society for Precision Engineering
• /
• v.30 no.4
• /
• pp.397-402
• /
• 2013

In this study, we carried out the each lines of section, using GC (green silicon carbide) whetstone, the SCM415 material which separated by after and before heat treatments process, in 3+2 axis machining centers for integrated grinding after cutting end mill works, the spindle speed 8000 rpm and feed rate 150 mm/min. For the analysis of the centerline average roughness (Ra), we measured by 10 steps stages. Using Finite element analysis, we found the result of the load analysis effect of the assembly parts, when applied the 11 kg's load on both side of the ATC (Automatic tool change) arm. The result is as follows. For the centerline average roughness (Ra) in the non-heat treatment work pieces, are appeared the most favorable in the tenth section are $0.510{\mu}m$, that were shown in the near the straight line section which is the smallest deformation of curve. In addition, the bad surface roughness appears on the path is to long by changing angle, the more inclined depth of cut, because the chip discharging is not smoothly.