• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1995.10a
• /
• pp.280-283
• /
• 1995

In centrifugal barrel finishing, it is easy to establish the optimum working conditions for different workpieces. As they are adjusted in trial and error practically, production efficiency and quality are some- times low In the present paper, firstly, installation of the barrel finishing machine, finishing purpose and working conditions have been analyzed in order to eliminate the defects of the finished surface. Secondly, on the basis of this result, quantity of the water and selection of the media and the compound, etc. have been investigated. As a result, production efficiency and quality have been improved under the specified optimum working conditions. In addition, durability of the media and the compound has been tested experimentally. As a result, it was found that the expected life of the media is about 85 hrs and that of the compound is about 5 hrs. Besides high quality control has been achieved by newly proposed inspection at regular intervals.

• Journal of Life Science
• /
• v.9 no.2
• /
• pp.5-8
• /
• 1999

We isolated a sphingonyelinase (SMase) inhibitor, which would be a potential reagent to regulate cell proliferation, oncogenesis, and inflammation, from a strain of Streptomyces sp.. In this paper, we report the optimal conditions for the production of SMase inhibitor, designed as sphinin, from Streptomyces sp. F50970. The optimal carbon and nitrogen source were 1% soluble starch and 0.05%-0.15% trypton. Most of monosaccharides and high concentration of soluble starch above 1.0% caused falling of pH and sphinin production. Zn2+, Cu2+, Fe2+, Mn2+, and Co2+inhibited cell growth and the production of sphinin. Inorganic phosphate promoted the sphinin production. Optimal initial pH for the production of sphinin was 7.5-8.0. Addition of CaCO3 to the medium resulted in an increase of inhibitor production. Based on these results, we designed a fermentation medium for the production of a SMase inhibitor, sphinin, from Streptomyces sp. F50970.

• Structural Engineering and Mechanics
• /
• v.61 no.3
• /
• pp.389-396
• /
• 2017

Concrete pavements are subjected to traffic and environmental loadings. Repetitive type of such loading cause fatigue distress which leads to failure by forming cracks in pavement. Fatigue life of concrete pavement is calculated from the stress ratio (i.e. the ratio of applied flexural stress to the flexural strength of concrete). For the correct estimation of fatigue life, it is necessary to determine the maximum flexural tensile stress developed for practical loading conditions. Portland cement association PCA (1984) and Indian road congress IRC 58 (2015) has given charts and tables to determine maximum edge stresses for particular loading and subgrade conditions. It is difficult to determine maximum stresses for intermediate loading and subgrade conditions. The main purpose of this study is to simplify the analysis of rigid pavement without compromising the accuracy. Equations proposed for determination of maximum flexural tensile stress of pavement are verified by finite element analysis.

• Journal of Drive and Control
• /
• v.14 no.1
• /
• pp.29-34
• /
• 2017

This study analyzed a life test method for a power take-off (PTO) gearbox. An engine transfers mechanical power (rotation and torque) to a hydraulic pump through a PTO Gearbox with one input shaft and three output shafts. PTO gear box durability under high loads over long time periods was tested using dynamometers. In order to reflect the rated operating conditions, power must be distributed to each output shaft, and experiments were conducted under various conditions to verify the characteristics of the distributed power. An accelerated life test was designed using speed and torque as acceleration factors. Also, efficiency tests were conducted under various load conditions. Also, a lubrication oil composition analysis was performed to analyze gearbox wear status.

• Journal of Life Science
• /
• v.10 no.2
• /
• pp.182-187
• /
• 2000

The optimized RAPD-PCR conditions, which can be utilized as a basic information for the analysis of the genetic characteristics were investigated with four onion varieties, named Changryungdaego, Yeoeuijuhwang, Yakwangju, and Dabonghwang using Operon primers, OPR01 (TGCGGGTCCT) and OPZ20 (ACTTTGGCGG). We tested several concentrations of DNA, primer, and MgCl2, annealing temperature, number of PCR cycle, and presence/absence of pre-heating time at the begining of PCR reation in the 25${mu}ell$ volume. The best RAPD profiles were obtained using 50ng of DNA, 5mM of primer, 1.5mM of MgCl2, 45$^{\circ}C$ of annealing temperature and an absence of pre-heating time. An establishment of the stable and reproducible RAPD-PCR conditions are expected to be useful for the subsequent RAPD-related investigation, such as genetic characterization of the onion strains, re-establishment of phylogenetic relationships and development of new varieties.

• Korea journal of population studies
• /
• v.8 no.1
• /
• pp.20-46
• /
• 1985

The increase of the population has an effect on the increase of students. The high birthrate, which means the extension of enrollments in the future, requires preparation of enough facilities and equipment for education. However, the educational conditions of Korea are not yet developed, and in such a situation the increase of enrollments makes the improvement of educational conditions difficult. Besides, the influx of students into the large cities has made complex educational problems such as a decrease of students in the rural area and a change for the worse of the educational conditions in the urban area. For the development of education in such a situation, an emphasis should be put not only on security of a stable educational finance but also on activation of family planning project and curb of population influx into large cities in the realm of population policy. In addition, population education for the youth should be strengthened in order that they can have sound view of family life, married life, children, and sex moral. For the way the young married live has relationship with the number and quality of children in the future of our nation.

• Mass Spectrometry Letters
• /
• v.12 no.4
• /
• pp.163-171
• /
• 2021

Emiliania huxleyi is a marine phytoplankton that plays a critical role in global carbon and sulfur cycling. The genome of E. huxleyi has been sequenced, and an in-depth proteomic profile of this organism has been reported. This study analyzed the phosphoproteome of E. huxleyi and identified its changes under calcium-limited conditions. A TiO₂ microcolumn was used for phosphopeptide enrichment, followed by liquid chromatography-tandem mass spectrometry analysis. Overall, we identified 7,010 phosphorylated sites on 3,355 phosphopeptides associated with 2,929 phosphoproteins in E. huxleyi. Quantitative analysis revealed changes in the phosphoproteome in E. huxleyi when ambient conditions changed to calcium-limited conditions, notably the phosphorylation of some transporters was altered. This study provides an overview of protein phosphorylation in E. huxleyi and paves the way for further investigations of its biological functions.

• BMB Reports
• /
• v.54 no.7
• /
• pp.344-355
• /
• 2021

Mucins are high molecular-weight epithelial glycoproteins and are implicated in many physiological processes, including epithelial cell protection, signaling transduction, and tissue homeostasis. Abnormality of mucus expression and structure contributes to biological properties related to human cancer progression. Tumor growth sites induce inhospitable conditions. Many kinds of research suggest that mucins provide a microenvironment to avoid hypoxia, acidic, and other biological conditions that promote cancer progression. Given that the mucus layer captures growth factors or cytokines, we propose that mucin helps to ameliorate inhospitable conditions in tumor-growing sites. Additionally, the composition and structure of mucins enable them to mimic the surface of normal epithelial cells, allowing tumor cells to escape from immune surveillance. Indeed, human cancers such as mucinous carcinoma, show a higher incidence of invasion to adjacent organs and lymph node metastasis than do non-mucinous carcinoma. In this mini-review, we discuss how mucin provides a tumor-friendly environment and contributes to increased cancer malignancy in mucinous carcinoma.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.12 no.1
• /
• pp.636-643
• /
• 2020

This study developed a method for simulating greenhouse gas (GHG) emissions considering changes in conditions that may occur during the actual operation of small ships. Additionally, we analyzed and compared the results of the proposed method with that of existing emission simulations according to life-cycle assessment (LCA), thus verifying the proposed method's effectiveness. Through the results of the study, we confirmed that the proposed method improves the simulation by considering emissions due to ship operation, whereas existing methods focus on emissions caused by raw material production. Additionally, the proposed method could identify and quantify the relationship between changes in operating conditions and GHG emissions. We expect this GHG emissions simulation technique to help improve the environmental performance of ships in the future.

• International conference on construction engineering and project management
• /
• 2024.07a
• /
• pp.193-200
• /
• 2024

This research focuses on the extent to which the water efficiency elective items of the LEED certification system adapt to the environmental characteristics of regions with varying climatic conditions. The building industry, is being called upon to promote energy-efficient construction, and the issues surrounding water resources are becoming increasingly severe, underscoring the importance of sustainable water resource management. Based on the hypothesis that, despite its global recognition and widespread adoption, the LEED certification does not always adequately address the environmental realities of all regions, this study analyzed new construction cases certified by LEED in the United States, Japan, and Taiwan from 2019 to February 2024. The analysis revealed regional differences based on water efficiency elective items and certification level trends under different climatic conditions. The findings suggest that the LEED certification system may not fully respond to the environmental situations and water resource issues in all regions, raising concerns about the adaptability of water efficiency items and the potential for similar issues in other evaluation items.