• Journal of Korean Society of Forest Science
• /
• v.103 no.2
• /
• pp.264-269
• /
• 2014

The aim of this study was to determine the current distribution area of Robinia pseudoacacia habitat and to estimate its stand yield as well as its carbon stocks. In order to do so, the area of R. pseudoacacia distribution is obtained based on the large-scaled forest type map (1:5,000). Also, Weibull diameter distribution model is used to predict the yield of R. pseudoacacia stands. In addition, carbon emission factor is applied to calculate carbon stocks and removals. To obtain the stand yield of R. pseudoacacia, we developed estimation equation considering growth factors of the stand, e.g. mean diameter, the basal area, maximum and minimun diameter and etc. and tested it to ensure accuracy. Consequently, estimation equation derived from all growth factors have shown significance that could also be used for analysis. Site index was also established to determine the productivity of the forestland that later turned out to be ranging from 16 to 22. Based on these results, stand yield tables were drawn up. R. pseudoacacia is widely distributed in inland areas of Gyeongsang, Chungcheong and Gyeonggi provinces which covers total area of 26,770 ha. And when it is converted into carbon stocks, it amounts to 2,517,598tC with annual carbon uptake of 3.76tC/ha which is comparable to Querqus species that is known to storer large amounts of carbon. Therefore, R. pseudoacacia is also expected to serve as a viable carbon pool that would contribute to the mitigation of climate change. Furthermore, stand yield tables, an outcome of this survey would assist not only in proper management but also in sustainable management policy of R. pseudoacacia.

• Korean Journal of Food Science and Technology
• /
• v.23 no.1
• /
• pp.76-80
• /
• 1991

To isolate oryzanol from the by-product of rice bran oil refinning, experiment of solvent fractional crystallization was carried out at various conditions with the dark oil obtained by acidifying the soap stock of micella refinning process and the pitch obtained from vacuum distillation of the dark oil. The impurity interfering the crystallization process such as waxes can be removed as precipitates by cooling the 1:1 mixtrue of acetone and dark oil to $0^{\circ}C$, From the dewaxed dark oil, oryzanol concentrate with 51.3% purity was obtained by fractional crystallization at$0^{\circ}C$ with the mixture of 8 part volume of hexane and 1 part of the dewaxed dark oil. The concentrate was recrystallized at room temperature with 20 part volume of methanol to yield oryzanol crystal of 98.3% purity. The optimum condition of vacuum distillation was temperature of $180^{\circ}C\;at\;0.2{\sim}0.4\;torr$ with 2% steam sparging. At this condition, the free fatty acid in the dark oil was removed as distillate without thermal deomposition to yield 82.3% of oryzanol as the pitch of 27.3% purity. After concentration from the pitch with 20 part volume of hexane to yield yellow powder of 75.4% purity, the yellow powder was recrystallized in methanol at room temperature to obtain the crystal containing 99.0% oryzanol. The overall oryzanol yield from the dark oil and the pitch was 9.5 and 28.5%, respectively. The change of the composition of sterols and triterpenoid alcohols in the compounds isolated during fractionation was analyzed by GC-MS.

• Microbiology and Biotechnology Letters
• /
• v.46 no.3
• /
• pp.234-243
• /
• 2018

The Antarctic Ocean contains numerous microorganisms that produce novel biocatalysts that can have applications in various industries. We screened various psychrophilic bacterial strains isolated from the Ross Sea and found that a Croceibacter atlanticus strain (Stock No. 40-F12) showed high lipolytic activity on a tributyrin plate. We isolated the corresponding lipase gene (lipCA) by shotgun cloning and expressed the LipCA enzyme in Escherichia coli cells. Homology modeling of LipCA was carried out using the Spain Arreo lake metagenome alpha/beta hydrolase as a template. According to the model, LipCA has an ${\alpha}/{\beta}$ hydrolase fold, Gly-X-Ser-X-Glymotif, and lid sequence, indicating that LipCA is a typical lipase enzyme. Active LipCA enzyme was purified fromthe cell-free extract by ammonium sulfate precipitation and gel filtration chromatography. We determined its enzymatic properties including optimum temperature and pH, stability, substrate specificity, and organic solvent stability. LipCA was immobilized by the cross-linked enzyme aggregate (CLEA) method and its enzymatic properties were compared to those of free LipCA. After cross-linking, temperature, pH, and organic solvent stability increased considerably, whereas substrate specificities did not changed. The LipCA CLEA was recovered by centrifugation and showed approximately 40% activity after 4th recovery. This is the first report of the expression, characterization, and immobilization of a C. atlanticus lipase, and this lipase could have potential industrial application.

• Journal of Korean Library and Information Science Society
• /
• v.9
• /
• pp.241-266
• /
• 1982

This paper gives a summary and overview of a survey conducted at the catalogues of five universities in Daegu during November 1982. The major objective of this study was to secure information about user needs in order to improve the catalogue in Korean university libraries. Data was collected by a combined method of questionnaire and interview. A total of 379 respondents were taken on a randomly selected sample of catalogue users. Results of the survey can be summarized as follows: 1. Eighty-eight percent of the students answered that they had used the library more than twice a month. Nevertheless the number of students consulting the catalogue with the same frequency was only 220, or a n.0, pproximately 58 percent. Those who used the library most tended to use the catalogue more than those who rarely came to the library. 2. Those who had been shown how to use their own catalogue were only 32.5percent of which the students found the instruction sufficient for them to be able to use the catalogue were only 37.5 percent. In particular, they stated that instructions by printed materials and/or library orientation were so poor that they didn't give much help in using the catalogue. This problem makes many libraries to review their own method of instruction in order to encourage patrons to use the catalogue more effectively. 3. Most of the students consulted the catalogue in order to locate library materials. Known-item searches and subject searches were 84 and 16 percent respectively. While 70.5 percent of the students used the author-title catalogue without any difficulties, only 35.5 percent of those stated that using the classed catalogue was easy. 4. It was surprising that the number of students using title access in the search was far greater than that of students using author access. In contrast with this, other studies conducted by many earlier overseas investigators revealed that the great majority of patrons tended to use the latter first. Therefore, we should put more emphasis on the title entries in the catalogue itself as well as cataloging rules. 5. Most useful bibliographic elements in the entry were author, title, call number, date and publisher whereas edition, series statement and the location of publisher were rarely used compared with the other elements. Content note was the most desirable element in the entry to be involved, for many catalogers were used not to describe it on the note area. 6. The chief reason given for not using the catalogue was "I can manage without it" with "It's difficult to understand contents of the card entry." The other one was "It's useless to search materials by the catalogue because I've failed so many times to obtain them out of the stock." In response to this, circulation and acquisition system should be improved not to make such complaints any more.

• Korean Journal of Materials Research
• /
• v.11 no.8
• /
• pp.690-696
• /
• 2001

$TiO_2$ coated coal fly ash has been prepared in order to develop the low price $TiO_2$ photocatalyst and spread out its utilizing field. $TiO_2$ particles is coated on the surface of coal fly ash by precipitation method. In this method, $TiCl_4$ aqueous solution was used as a titanium stock solution and $NH_4HCO_3$ was used as a precipitant. The titanium hydroxide precipitated on the surface of coal fly ash in these neutralizing reaction process was oxidized by heat treatment in temperature ranges of $300~700^{\circ}C$. The crystal structure of the generated titanium dioxide showed anatase type. The crystal size of titanium dioxide increased with raising the temperature of heat treatment, but the removal ability of NO gas decreased. When the titanium dioxide was heated at temperature ranges of $300~ 400^{\circ}C$ for 2 hours, the crystal size of titanium dioxide appeared about 9nm, and the removal rate of NO gas showed 85~ 92%. The whiteness of $TiO_2$ coated coal fly ash increased with raising the coating rate of titanium dioxide and the temperature of heat treatment.

• Korean Journal of Environment and Ecology
• /
• v.18 no.3
• /
• pp.316-325
• /
• 2004

This study was carried out to survey the usability of Vitex rotundifolia as an afforestation and landscaping plant on destroyed slopes, sandyhills of sea boards, and places in need of landscaping. The growth characteristics of seedlings and rooted cuttings of Vitex rotundifolia in soils of varying properties and water content ere studied. In three test soils, with a water content of 5% each, the survival rate was more than 70ole for seedlings and more than 40％ for rooted cuttings. This demonstrates that Vitex rotundifolia is a very strongly xeric tree species. The length of stem, the diameter of root stock, leaves, and the length of root increased in all the three types of soil as the quantity of soil water increased. The difference of the growth in response to the water content of the soil was most pronounced in the length of the stem. The growth of seedlings was most notable in the weathered granitic soil. The sea sand and the red silt loam came second and third, respectively. However, there was no major difference in the three test soils. Thus, Vitex rotundifolia appears well-suited to several soil properties and soil water quantities, which makes it very useful as an afforestation and landscaping plant in various sites.

• KDI Journal of Economic Policy
• /
• v.14 no.4
• /
• pp.27-49
• /
• 1992

This paper stresses the role of market fundamentals rather than bubbles in explaining Korea's recent experience of large fluctuations of stock and real estate prices. The bubble story that emphasizes the self-fulfilling prophecies of investors seems to be inappropriate to explain the recent changes of assets prices in Korea. Those who argue for bubble phenomenon in Korea tend to interpret the volatile movements of assets prices as some form of bubbles, but without implementing a rigorous test on the presence of bubbles. Even when some bubble tests are carried out, such studies exhibit various econometric problems in testing. More seriously, they suffer from the misspecification problems in setting up a market model. This paper has shown that Korea's recent changes in assets prices could be explained by changes in market fundamentals according to the emergence and the subsequent fading of 'three lows'. First, it tried to explain changes in assets prices by changes in such market fundamentals as real interest rates and economic growth. Second, it showed that the real estate prices overshoot when the liquidity and exchange rates change, using the two-sector general equilibrium portfolio balance model. It is argued that the rapid rise in real estate prices during 1986-89 stems from Yen's and Won's appreciation $vis-{\grave{a}}-vis$ the U.S. dollar and liquidity expansion (or decreases in real interest rates), while the downturn in real estate prices since 1990 is associated with Yen's and Won's depreciation $vis-{\grave{a}}-vis$ the U.S. dollar and rises in real interest rates in reflection of the excess demand for liquidity.

• The Journal of Korean Academy of Prosthodontics
• /
• v.42 no.4
• /
• pp.425-442
• /
• 2004

Statement of problem: A difficulty in achieving a passive-fitting prosthesis can be overcome by individual crown restoation of multiple implants. But individualized crown has another difficulty in control of contact tightness and stress distribution. Purpose: This in vitro study is to evaluate the stress distribution and the magnitude in the supporting tissues around Endopore implants with different crown lengths, interproximal contact tightness, and the splinting effects. Material & methods: Three Endopore implants($4.1{\times}9mm$) were placed in the mandibular posterior edentulous area distal to the canine and photoelastic model was made with PL-2 resin(Measurements Group, Raleigh, USA). Restorations were fabricated in two crown lengths: 9, 13 mm. For non-splinted restorations, individual crowns were fabricated on three custom-milled titanium abutments. After the units were cemented, 4 levels of interproximal contact tightness were evaluated: open, ideal($8{\mu}m$ shim stock drags without tearing), medium($40{\mu}m$), and heavy($80{\mu}m$). For splinted restorations, 3-unit fixed partial dentures were fabricated. This study was examined under simulated non-loaded and loaded conditions(6.8 kg). Photoelastic stress analysis was carried out to measure the fringe order around the implant supporting structure. Results: 1. When restorations were not splinted, the more interproximal contact tightness was increased among the three implants, the more stress was shown in the cervical region of each implant. When crown length was increased, stresses tended to increase in the apex of implants but there were little differences in stress fringes. 2. When nonsplinted restorations were loaded on the first or third implant, stresses were increased in the apex and cervical region of loaded implant. Regardless of interproximal contact tightness level, stresses were not distributed among the three implants. But with tighter interproximal contact, stresses were increased in the cervical region of loaded first or third implant. 3. When the nonsplinted restorations were not loaded, there were little stresses on the supporting structure of implants, but low level stresses were shown in the splinted restorations even after sectioning and soldering. 4. With splinted restorations, there were little differences in stresses between different crown lengths. When splinted restorations were loaded, stresses were increased slightly on the loaded implant, but relatively even stress distribution occurred among the three implants. Conclusions: Splinting the crowns of adjacent implants is recommended for Endopore implants under the overloading situation.

• Journal of Technology Innovation
• /
• v.21 no.1
• /
• pp.27-57
• /
• 2013

The projects of agricultural R&D investments have been evaluated largely on the basis of efficiency better than equity although both criteria are equally critical in that major fund source of agricultural R&D investments is public budget. In this study, I focus on equity aspects by identifying the heterogeneous impacts of public knowledge created by R&D on farm efficiencies by farm income levels using bias-corrected DEA and quantile regression with panel data. The findings indicate that entire farms haven't been likely to be benefited evenly from public knowledge stock created by agricultural R&D, in particular high income farms can have enjoyed relatively more benefits of its in terms of efficiency gain. Those can imply agricultural R&D have functioned in the way analogue to digressive subsidies. In addition, the heterogeneous technological needs different among income level farms turns out to be main underlying factors affecting such the skewed benefit distribution of agricultural R&D over different income level farms.

• Food Science of Animal Resources
• /
• v.30 no.5
• /
• pp.703-716
• /
• 2010

It has recently been considered urgent to establish an accurate definition and scope of functional foods in the livestock industry in Korea. The tertiary function of food is gradually emphasized with various changes in conditions such as international competitive power enhancement of the whole world, including Korea. Therefore, the purpose of this study was carried out to gather basic information toward the establishment of standardization, management plans, and a system adapted to the Korean state through researching management systems of functional meat and meat products in the European Union (EU) and the Oceania Area (OA). A brief summary of this study is as follows. In the EU and OA, special management systems and laws about functional livestock and products were once nonexistent; only 'nutrition claims' and 'health claims' operated in the nutritional consolidation side of foods. Also, it was once thought that functional index materials and permissions established in the application of functional products sufficed, because management standards for enriched food were not established. Therefore, standardization of functional live stock products needs to be considered based on the case of developed countries in the EU and OA. It also seems that the above functional indicative substances can be applied, based on normal standards of indicative substances of functional products and the normal standards of indicators of functional substances added to livestock products presented in this study.