• Economic and Environmental Geology
• /
• v.37 no.1
• /
• pp.143-151
• /
• 2004

This study focused on examining the possibility of recycling mine solid waste as environmental materials, especially for porous media. Basic properties including mineralogical compositions, chemical compositions, and particle size distribution of the tailings from the Sangdong W mine were checked. The mineralogical and chemical compositions of the tailings samples were not much different in depth. According to Korean Standard Leaching Test for Wastes(KSLT), concentrations of heavy metals leached from the tailings were below the standard values. As a result of particle size analysis, the median diameter (d$_{50}$) of the tailings was in the range of 10 to 30 ${\mu}{\textrm}{m}$. The stable tailings slurry made up of 3 ${\mu}{\textrm}{m}$ in d$_{50}$ was prepared using Attrition Mill. The milling condition was 40 vol% in slurry concentration, 700 rpm in stirring speed, and 1 hour in milling time. PEI was added as dispersing agent. Concentrated slurry was extended to 3 times by foaming method. In the case of 3 times foamed slurry, the total and open porosity of ceramic supports sintered at 1,075$^{\circ}C$ for 90 minutes was about 80% and 72%, respectively. Pore size was in the range of 30∼350${\mu}{\textrm}{m}$. Therefore, the tailings could be recycled starting material for environmental materials such as macroporous ceramic support.

• Food Science and Preservation
• /
• v.11 no.3
• /
• pp.313-318
• /
• 2004

This study was conducted to compare development of browning in minimally processed mushrooms (Agaricus bisporus Sing.) by picking season and postharvest holding time of the raw material. 'White' type of the mushrooms were harvested and minimally processed immediately after harvest or holding at 2$^{\circ}C$ for 7 days after picking in 4 seasons. The processed mushrooms were kept at 5$^{\circ}C$, and changes in surface color and content of total phenolic compounds of the mushrooms were measured. Respiration rate of the whole mushrooms was ranged from 9.55 to 17.93 mL C0$_{2}$/kg$\cdot$ hr, and the rate was low in mushrooms harvested in summer and autumn compared with those picked in spring and winter. Hunter L value of the mushrooms decreased rapidly just after slicing, especially in summer-harvest mushrooms. The mushrooms processed with the raw materials stored at 2$^{\circ}C$ for 7 days after harvest showed the lowest 'L' value among the sliced mushrooms prepared at different holding time. Consequently, summer-harvest mushrooms and the mushrooms kept at 2$^{\circ}C$ for more than 7 days after harvest would be unsuitable for minimally processing due to rapid browning.

• Food Science and Preservation
• /
• v.12 no.6
• /
• pp.552-557
• /
• 2005

Effect of pre- and post-mild heat treatment on quality of fresh-cut potatoes was investigated with the focus on surface color, firmness, phenolics, vitamin C and sensory characteristics. As the pre-heat treatment before cutting of potatoes, dried hot air (DH) and hot water (WH) treatment were conducted at $45^{\circ}C$ for 60 min, respectively. As a post-heat (CH) treatments, potato cubes were dipped into water of $55^{\circ}C$ for 45 seconds after cutting. The potato cubes were packed in 15 cm x 20 cm LDPE pouches $30^{\mu}m$ thick and then stored at $5{\pm}1^{\circ}C$. The respiration rate of fresh-cut potatoes was decreased by mild heat treatment Especially, the rate of cubes treated with DH was decreased by $20\%$ compared to that of the non-heat treated. L value of cubes treated with DH showed higher value than that of others. Firmness and free phenolics had no significant difference between the treatments. The fresh-cut potatoes prepared with non-heat treatment showed higher vitamin C content than that of the heat treated. In sensory visual color, CH treated cubes marked the best quality. Conclusively, mild heat treatment, especially CH treatment, showed positive effect on browning inhibition and quality enhancement of fresh-cut potatoes.

• Food Science and Preservation
• /
• v.12 no.6
• /
• pp.540-545
• /
• 2005

This study was conducted to evaluate the efficacy of high a)z pre-treatment (60, $100\%$ for 3, 6, 12 hr) on quality of 'Hikawa Hakuho' peach fruits. High a)z treatment inhibited the respiration and ethylene production, especially with long tenn treatment for more than 6 hr. Discoloration of peel, softening and decay were reduced by high $CO_2$ treatment $CO_2$ concentration of $60\~100\%$ did not affect soluble solids content and titratable acidity of fruits. $CO_2$ treated fruits, however, showed higher sweetness score compared with control. As the $CO_2$ concentration and treatment duration increased from 60 to $100\%$ and from 3 to 12 hr, respectively, the efficacy on quality increased. Fruits treated with $100\%\;CO_2$ for 3 hr and $60\%\;CO_2$ for 12 hr, however, showed very low flavor score due to the residual $CO_2$ in flesh. High $CO_2$ injury was not noted at any $CO_2$ levels tested in this study. Above results suggest that $60\%\;CO_2$ treatment for 6 hr resulted in as good control of respiration, ethylene production, decay, discoloration and softening without off-order.

• Journal of Broadcast Engineering
• /
• v.11 no.3 s.32
• /
• pp.349-362
• /
• 2006

There are several data broadcasting standards that the developers should apply when develops any interactive digital TV contents. In Korea, we adopts ACAP(Advanced Common Application Platform) as terrestrial data broadcasting standard, MHP(Multimedia Home Platform) fur satellite data broadcasting and OCAP(OpenCable Application Platform) for cable data broadcasting. Therefore, content providers must develop different applications which suited for different standards - even if the application is exactly same. This is waste of time and energy. This paper suggests a solution to solve this problem among different broadcasting platforms - MHP, OCAP and ACAP. We compared these specifications, and found out what APIs are typically used far applications. Then we designed XML file structures that can be used to define contents of applications. We also implemented an authoring tool which automatically generates XML files by interaction with users. This paper also ascertains Xlet applications, produced by the authoring tool, works properly on each different data broadcasting standard - MHP, OCAP and ACAP.

• International Commerce and Information Review
• /
• v.17 no.3
• /
• pp.203-222
• /
• 2015

Papers in FTA research have mostly focused on the legal interpretation of the FTA treaties. In this research, more focus was put on the customs laws and related cases delivered in the U.S. federal courts, by which we can analyze the Korea-U.S. FTA in more practical manner to derive the enterprises' solutions to cope with the disputes of FTA preferential duty. The Tariff Act of 1930 is the U.S. customs law to govern FTA preferential duties. The administrative practices with customs duties are coordinated with the FTA rules. The most controversial issue in the U.S. customs law lies in the classification of imported goods for imposition of the customs duties, based on Harmonized Tariff Schedule of the United States. It was found that the U.S. federal courts had been quite favorable to the CBP(U.S. Customs and Border Protections) in litigation with the private importers and exporters. The reason seems to be that the CBP has been dealing with the customs cases so many times, accumulating much experience in execution of the U.S. customs laws, which is likely to make their decisions on customs duties almost free of errors. Therefore, the Korean exporters need to collect the CBP's past cases on the denial of preferential treatment on imported goods and be fully informed of the CBP's policies on the FTA preferential duty treatment.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.26 no.10
• /
• pp.851-868
• /
• 2015

A radio telescope which has been dominantly used for millimeter and submillimeter wave radio astronomy is a cassegrain antenna. A various receivers with specified observing bandwidths are installed on cassegrain antenna so as to carry out to investigate a diverse radio astronomy. A beam guiding system should be required so that a various receiver can be conducted their own observational frequency bands. The beam guiding system based on Gaussian beam transmission theory consists of quasi-optical circuit used such ellipsoidal mirror, dielectric lens and feed horn. In this paper, not only Gaussian beam transformations based on Gaussian beam theory are presented, but also design techniques for quasi-optical circuit are given. By using proposed design techniques, both Gaussian beam quasi-optical circuits to be used for cassegrain antenna and design results are also described. Properties of key focusing elements such ellipsoidal mirror and dielectric lens and feed horn are also discussed. It is expected that beam guiding system to be applied cassegrain antenna could be easily designed by using proposed design techniques.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.13 no.3
• /
• pp.547-554
• /
• 2018

Wind energy is widely recognized as one of the cheapest forms of clean and renewable energy. In fact, in several countries, wind energy has achieved cost parity with fossil fuel-based sources of electricity generation for new electricity generation plants. Offshore wind energy development promises to be a significant domestic renewable energy source for the target of korea government 3020 plan. A pivotal activity during the development phase of a wind project is wind resource assessment. Several approaches can be categorized as three basic scales or stages of wind resource assessment: preliminary area identification, area wind resource evaluation, and micrositing. This study is to estimate the wind power capacity of chonnam province offshore area using three basic stages based on the six meteorological mast data. WindPRO was used, one of a well-known wind energy prediction programs and based on more than 25 years of experiences in development of software tools for wind energy project development. The design results of offshore wind power generation capacity is calculated as total 2.52GW with six wind farms in chonnam offshore area.

• Transactions of the Korean hydrogen and new energy society
• /
• v.28 no.1
• /
• pp.9-16
• /
• 2017

Hydrogen forms metal hydrides with some metals and alloys leading to solid-state storage under moderate temperature and pressure that gives them the safety advantage over the gas and liquid storage methods. However, it has disadvantages of slow hydrogen adsorption-desorption time and low thermal conductivity. To improve characteristics of metal hydrides, it is important that activation and thermal conductivity of metal hydrides are improved. In this study, we have been investigated hydrogen storage properties of Hydralloy C among Ti-Mn alloys. Also, the characteristics of activation and thermal conductivity of Hydralloy C were enhanced to improve kinetics of hydrogen adsorption-desorption. As physical activation method, PHEM (planetary high energy mill) was performed in Ar or $H_2$ atmosphere. Hydralloy C was also activated by $TiCl_3$ catalyst. To improve thermal conductivity, various types of ENG (expanded natural graphite) were used. The prepared samples were compacted at pressure of 500 bar. As a result, the activation properties of $H_2$ PHEM treated Hydralloy C was better than the other activation methods. Also, the amounts of hydrogen storage showed up to 1.6 wt%. When flake type ENG was added to Hydralloy C, thermal conductivity and hydrogen storage properties were improved.

• Korean Journal of Construction Engineering and Management
• /
• v.16 no.4
• /
• pp.107-117
• /
• 2015

As the demand for urban business hotel has increased in the recent years due to the sharp rise in overseas tourists, the potential of business hotel development has gained in financial attention for the real estate investment. However, its concept and business domain has not been defined, and none of investment guidance for the development has not been clarified. Accordingly, this report intends to define the concept of urban business hotel in perspective of real estate investment through prior case studies and literature review, and provide the structure of determinants which control its investment decisions. Furthermore, this study develops the weight of determinants depending on the type of investment, and evaluate the two actual projects in urban area of Seoul, differed from investment type: direct and indirect, based on AHP and Fuzzy methodologies. Research finding indicate that the financial factors affecting the sales and tour business condition factors are critical determinants regardless of investment type. And it is notable that the direct investment perspective pays more attention on the finance and investment associated determinants while the indirect one more focuses on the regional and environmental ones. From the analysis of case evaluation, it is also noteworthy that the direct investors turn out to be more conservative than indirect investors due to the risk of equity capital investment.