• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2002년도 춘계학술대회 논문집
• /
• pp.922-925
• /
• 2002

Klystron which is micro wave amplifier tube are mainly used in fields of science such as accelerator, nuclear fusion, broadcasting, communication fields, and defense industry fields, tract. The quality of Klystron anode and cavity are determined by form accuracy and roughness of the worked surface. Therefore anode and cavity are restricted the from accuracy strictly and the surface roughness be under Rmax 0.03S. As a work material of anode and cavity, the oxygen-free copper, that is used for optical pares of aerospace and laser mirror is selected. An outside diameter of material is $\Phi$100 mm and an inside diameter is $\Phi$30~33 mm. In this study, to find the optimum ultra precision cuffing condition of oxygen-free copper with diamond turning machine, the surface roughness is examined for various diamond toot nose radius, main spindle speed, fred rate and depth of cut. As a result of experiment, we could machined the anode and cavity with a surface roughness within Ra 3.2 nm, a form accuracy within 0.01 $\mu\textrm{m}$.

• 한국실내디자인학회논문집
• /
• 제15권5호
• /
• pp.141-148
• /
• 2006

Recently, human's life is more longer and the birth rate continually decrease by the development of medical technology. In 2026 the ratio of the elderly will come up to 20.8% and be a 'post-aged society'. Development of economy and industrialization not only accelerate the urbanization and formation of nuclear family, but also change the changing of traditional society and one's value. So the issue of society and value's changing in the elderly increase the centralizing in the silver industry, and by the recent research about the elderly, they not want to live with their children, but want to live independently. This study is meaningful at the next generation of Ubiquitous society and post-aged society, proposing the smart silver town in urban type and let the elderly keeping the existing life in city. It realize the concept of 'Aging in Place' and propose the smart silver town in urban type which appropriate to behavior of the elderly, and being satisfy with various requirements of the elderly. This study point up the combination of physical elements and electronic elements through the smart technology, and making an smart environment to compose the smart silver town in urban type which react the behavior of the elderly.

• 대한산업공학회지
• /
• 제41권3호
• /
• pp.259-266
• /
• 2015

Among many energy resources, natural gas has recently received a remarkable amount of attention, particularly from the electrical generation industry. This is in part due to increasing shale gas production, providing an environment-friendly fossil fuel, and high risk of nuclear power. Because South Korea, the world's second largest LNG importing nation after Japan, has no international natural gas pipelines and relies on imports in the form of LNG, the natural gas has been traditionally procured by long term LNG contracts at relatively high price. Thus, there is a need of developing an Asian LNG trading hub, where LNG can be traded at more competitive spot prices. In a natural gas spot market, the amount of natural gas to be bought should be carefully determined considering a limited storage capacity and future pricing dynamics. In this work, the problem to find the optimal amount of natural gas in a spot market is formulated as a Markov decision process (MDP) in risk neutral environment and the optimal base stock policy which depends on a stage and price is established. Taking into account price and demand uncertainties, the basestock target levels are simply approximated from dynamic programming. The simulation results show that the basestock policy can be one of effective ways for procurement of LNG in a spot market.

• Journal of Applied Biological Chemistry
• /
• 제59권1호
• /
• pp.19-23
• /
• 2016

A phenol substance was extracted from Pinus koraiensis Siebold et Zucc leaf extracts and its biological efficacy was measured. The highest content of the phenol substance contained in Pinus koraiensis Siebold et Zucc leaves was 13.5 mg/g, which was obtained when it was extracted with 80% ethanol. At a concentration of 200 mg/mL, the phenolic substances extracted with 80% ethanol and water showed antimicrobial activities against Helicobacter pylori, producing clear zones of 10 and 12 mm diameter, respectively. Pinus koraiensis Siebold et Zucc. leaf extracts were separated using a Sephadex LH-20 column and 4 fractions were obtained (fractions A-D). Fractions C and D showed the greatest inhibitory activity against Helicobacter pylori producing 10.1 and 12.3 mm clear zones, respectively. These two fractions were purified using a Sephadex LH-20 and MCI-gel column ($H_2O{\rightarrow}100%$ ethanol). Purified compounds A and B were identified as syringic acid and compound C was identified as p-coumaric acid based on $^1H$-nuclear magnetic resonance (NMR), $^{13}C$-NMR, and fast atom bombardment mass spectrometry spectra. When two or more purified compounds were mixed, a synergistic effect of anti-Helicobacter pylori activity was evident. This result indicates that extracts of Pinus koraiensis Siebold et Zucc leaves could be considered a functional food because of their high antimicrobial properties.

• Journal of Radiation Protection and Research
• /
• 제45권1호
• /
• pp.26-34
• /
• 2020

Background: We examined changes in red ginseng components after different doses of irradiation were applied. We also evaluated what housewives and teachers know about irradiated food, as well as their perceptions of and attitudes toward it. Materials and Methods: General nutrients and unique components of irradiated ginseng were then analyzed. Education on irradiated foods and red ginseng was provided to teachers and housewives on two occasions, and changes in their behaviors were evaluated via a qualitative survey. Results and Discussion: The ideal radiation dose to reduce the number of bacteria without changing the unique components of red ginseng is 7.5 kGy. Notably, after educational seminars on this topic, consumers' knowledge, attitudes toward, and perceptions of irradiated ginseng compared to non-irradiated red ginseng changed significantly. Conclusion: It is necessary to provide consumers with information on irradiated foods to promote the growth of the domestic food industry, and to improve public knowledge of the safety and effects associated with the irradiation of food.

• 대한기계학회논문집A
• /
• 제25권11호
• /
• pp.1705-1712
• /
• 2001

Mechanical component has striation with constant width and SEM can estimate fracture type and loading condition. SEM has benefit to fatigue fracture analysis but striation can be observed according to the kind of material and range of crack growth rate and can't. In this case, it needs AFM that can measure 3-dimensional surface profile with resolution of atomic size. In this study. to find fracture reason of torsion-mounted blade in nuclear plant, we estimate the relation between stress intensity factor range and root mean square roughness in 12% Cr steel by AFM and predict in-service loading condition of turbine blade. failure analysis is performed by finite element method and Goodman diagram on torsion-mounted blade.

• 한국정밀공학회지
• /
• 제13권2호
• /
• pp.84-93
• /
• 1996

Non-destructive inspection techniques using laser have been broading their application areas as well as growing their measurement skills together with the rapid development of circumferential technology like fiber optics, computer and image processing. The ESPI technique is already on the stage of on-line testing with commercial products in developed country nations. Especially, this technique is expected to be applied to the nuclear industry, automobile and aerospace because it is proper for the vibration measurement and it can be applied to objects of a high temperature. This paper describes the use of the ESPI system for measuring vibration patterns on the reflecting objects. Using this system, high-quality Jo fringes for identifying mode shapes are displayed. A bias vibration is introduced into the reference beam to shift the Jo fringes so that fringe shift algorithms can be used to determine vibration amplitude. Using this method, amplitude fields for vibrating objects were obtained directly from the time-average interferograms recorded by the ESPI system.

• 생약학회지
• /
• 제40권3호
• /
• pp.233-237
• /
• 2009

Lindera obtusiloba has been used for centuries as a traditional medicine in Korea and recently known to have an anti-fibrotic effect. In this report, we investigated the effect of hot water extract from L. obtusiloba (WELB) on the mast cell-mediated allergic inflammation and studied its possible mechanisms of action. WELB inhibited phorbol-12-myristate 13-acetate and calcium ionophore A23187 (PMACI)-induced histamine release in HMC-1 human mast cells. WELB reduced PMACI-induced gene expression and secretion of proinflammatory cytokines such as tumor necrosis factor-$\alpha$, interleukin (IL)-$1{\beta}$, IL-6, and IL-8. The inhibitory effect of WELB on the expression of proinflammatory cytokines was c-jun N-terminal kinase and nuclear factor-${\kappa}B$ dependent. These results indicate that WELB may be beneficial in the treatment of mast cell-mediated allergic inflammation.

• Natural Product Sciences
• /
• 제20권4호
• /
• pp.232-236
• /
• 2014

Acanthopanax divaricatus var. albeofructus (ADA) is commonly ingested as a traditional medicine or as a component of a health drink in Korea. In this phytochemical study, nine phenolics (1 - 9) and three lignans (10 - 12) were isolated from the MeOH extract of the stems of ADA. Chemical structures were elucidated by comparing spectroscopic data with reported values. Nuclear factor kappa B ($NF-{\kappa}B$) inhibitory activity of the isolated compounds was evaluated using an $NF-{\kappa}B$ luciferase assay in HepG2 cells. Among them, compounds 1, 3 - 8, and 11 showed significant inhibitory effects on $TNF{\alpha}$-induced $NF-{\kappa}B$ transcriptional activity in a dosedependent manner, with $IC_{50}$ values ranging from 13.25 to $37.36{\mu}M$. Further studies on potential anti-inflammatory effects and the benefits of phenolic and lignan components from ADA are warranted.

• 한국분무공학회지
• /
• 제16권2호
• /
• pp.82-89
• /
• 2011

When pipe components made of carbon steel in nuclear, fossil, and industry plants are exposed to flowing fluid, wall thinning caused by FAC(flow accelerated corrosion) can be generated and eventually ruptured at the position of pressure boundary. The aim of this study is to identify the locations at which local wall thinning occurs and to determine the turbulence coefficient related to local wall thinning. Experiment and numerical analyses for the tee sections of down scaled piping components were performed and the results were compared. In particular, flow visualization experiment which was used alkali metallic salt was performed to find actual location of local wall thinning inside tee components. In order to determine the relationship between turbulence coefficients and local wall thinning, numerical analyses were performed for tee components in the main feedwater systems. The turbulence coefficients based on the numerical analyses were compared with the local wall thinning based on the measured data. From the comparison of the results, the vertical flow velocity component(Vr) flowing to the wall after separating in the wall due to the geometrical configuration and colliding with the wall directly at an angle of some degree was analogous to the configuration of local wall thinning.