• Korean Journal of Soil Science and Fertilizer
• /
• v.40 no.5
• /
• pp.418-428
• /
• 2007

Physical and chemical properties of the aggregate by-products including sludge and crushed dust samples collected from the 21 private companies throughout the country were analyzed to evaluate possible usage of the by-products as artificial soil materials for plantation. The pH of the materials ranged from 8.0 to 11.0. The organic matter content was $2.85g\;kg^{-1}$, and the total nitrogen content and available phosphate content were low as 0.7 percents and $12.98mg\;kg^{-1}$, respectively. Exchangeable $Ca^{2+}$, $Mg^{2+}$, $K^+$, and $Na^+$ were 2.29, 0.47, 0.02 and $0.05cmol\;kg^{-1}$, respectively. Heavy metal contents were lower than the limits regulated by environmental law of Korea. Textural analysis showed that most of the materials were silt loam with low water holding capacity ranged from 0.67 to 7.41 percents, and with low hydraulic conductivity ranged from 0.4 to $2.8m\;s^{-1}$. Mineralogical analysis showed that the aggregate by product materials were mostly composed of silicate, alumina and ferric oxides except calcium oxide dominant materials derived from limestones. The primary minerals were quartz, feldspars and dolomites derived from granite and granitic gneiss materials. Some samples derived from limestone material showed calcite and graphite together with the above minerals. According to the result, it can be concluded that the materials could be used as the artificial soil material for plantation after proper improvement of the physico-chemical properties and fertility.

• Korean Journal of Soil Science and Fertilizer
• /
• v.46 no.6
• /
• pp.641-646
• /
• 2013

Chemical properties of agricultural soils in Korea have been investigated at four-year interval in order of paddy, polytunnel, upland, and orchard soils since 1999; polytunnel soils were investigated over the whole country in 2000, 2004, 2008, and 2012. Polytunnel soils were taken from the surface (0-15 cm) and subsurface (15-30 cm) at 2,651, 1,274, 1,374 and 1,374 sites in all provinces of South Korea. One hundred sampling sites located in more than 400 m altitude were additionally investigated in 2008 and 2012. Average of soil chemical properties in 2012 except Jeju province were 6.6 for pH, 3.2 dS $m^{-1}$ for EC, 37 g $kg^{-1}$ for organic matter (OM), 1,049 mg $kg^{-1}$ for available (Avail.) phosphate, 1.58 $cmol_c\;kg^{-1}$ for exchangeable (Exch.) K, 10.6 $cmol_c\;kg^{-1}$ for Exch. Ca, and 3.3 $cmol_c\;kg^{-1}$ for Exch. Mg. Except pH, averages of all chemical properties exceeded the upper limit of optimal range. The median values except pH showed a lower value than the averages. The pH, OM and Exch. Ca had slightly increased from 6.3 to 6.6, from 34 to 37 g $kg^{-1}$, and from 7.7 in 2000 to 10.6 $cmol_c\;kg^{-1}$ in 2012, respectively. The order of sample ratios exceeding the optimal range were Avail. $P_2O_5$ (83%) > Exch. Ca (80%) > Exch. K (70%) > Exch. Mg (65%) > EC (55%) > OM (48%) > pH (29%) in 2012. The order of sample ratios below the optimal range was OM (25%) > Exch. K (25%) > pH (20%), Exch. Mg and Avail. $P_2O_5$ (9%) > Exch. Ca (6%) in 2012. The excessive proportion of pH, Exch. Ca, Exch. Mg and OM slightly increased, while the insufficient proportion of those decreased. Approximately 55% of polytunnel soils exceeding EC 2 dS $m^{-1}$ was evaluated with salt accumulated soils having the risk of growth disorder of crops. Nutrient contents in polytunnel soils in Korea showed high level especially Avail. $P_2O_5$ and Exch. cations. Therefore, recommended fertilization based on soil testing or plant testing is needed for soil nutrient management.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.11 no.6
• /
• pp.175-183
• /
• 2016

The government set up "national happiness, the hope of a new era of national vision under' job center of the creative economy" to achieve by national goals in the first and figure achieved through the establishment of new growth engines of the youth unemployment problem solve and national level there are a number of business start-up support. September 8, 2015 announced the Government's look at the '2016 Year of the budget, the government for new growth engines greatly promoted the venture entrepreneurship ecosystem revitalization and research and development (R & D) the business for enhanced performance in 2017. According to the direction of this study is to evaluate the current creative economy business incubator at the comparison whether the correct orientation mainly entrepreneurs, entrepreneurs preliminary recognition of student entrepreneurship ecosystem. Entrepreneurs 113 people in that way, 71 people pre-entrepreneurs, students 60, workers were founding agencies conducted an online survey of 47 people, 16 people Investors, 50 public and 11 additional persons including a total of 368 people. This study is in line with the orientation of these entrepreneurs to create economic status and recognition of the Republic of Korea entrepreneurship ecosystem, pre- entrepreneurs, students will examine the comparative analysis around. Analysis, social perception of entrepreneurship is somewhat higher than it was confirmed that the negative response of 32.2% to 36.3% of positive response. Social awareness of entrepreneurs showed a 2-fold higher response rate than the negative of response of 17.1% to 41.7% responding that positive recognition for the current start-up environment is bad, the response is good response to higher response rate than 23.5% to 41.1% It showed. The percentage of responses that better respect the entrepreneurship environment of the future Republic of Korea showed a higher response rate than the rate of 23% in response to deteriorate to 41.2%, with 52.9% awareness is the percentage that responded that the bad part about the ruthless Korea's entrepreneurship environment in China good part as response rate approximately three times greater than the 17.7% showed high response rates. Social awareness of entrepreneurs experience the presence of the founding start-up experience was confirmed that the more negative the number increases, the more the contrary the number of start-up experience increased awareness of the current and future environment of entrepreneurship was identified as a positive entrepreneurship environment. Also recognized was confirmed to change the parent of the more positive changes in the start-up of entrepreneurs doctor also positive about entrepreneurship, start-up entrepreneurs start with a doctor's motivation for founding non-economic reasons than for economic reasons has confirmed Higher. This study showed the overall level overview analysis of the status and recognition of the Republic of Korea entrepreneurship ecosystem. Future studies need to be a proposal for an existing previous studies for more precise direction to go forth to analyze the entrepreneurship ecosystem with a focus on problems and improvement of the Republic of Korea entrepreneurship ecosystem.

• Food Science and Preservation
• /
• v.19 no.2
• /
• pp.301-307
• /
• 2012

The quality of brown rice vinegar that was produced via static culture (A) was compared with the quality of three types of domestic commercial brown rice vinegar (B, C, and D) and of three types of Japanese brown rice vinegar (E, F, and G). The results showed titratable acidity levels of 6.39%, 4.52-6.32%, and 4.51-4.89% in the static-cultured brown rice vinegar, the domestic commercial brown rice vinegars, and the Japanese brown rice vinegars, respectively. The pH levels were 3.28, 2.58-2.97, and 3.03-3.27 in the static-culture brown rice vinegar, the domestic commercial brown rice vinegars, and the Japanese brown rice vinegars, respectively, which show similar values of the static-culture brown rice vinegar and the Japanese brown rice vinegars. The total nitrogen (TN) values of the static-culture brown rice vinegar, the domestic commercial brown rice vinegars, and the Japanese brown rice vinegars were 0.24, 0.03-0.16, and 0.12-0.17, respectively, with the highest value for the static-culture brown rice vinegar, substantial differences among the domestic commercial brown rice vinegars, and similar contents among the Japanese brown rice vinegars. For free sugar, glucose was either detected only in a small quantity or not detected at all in the static-culture brown rice vinegar and the Japanese brown rice vinegars, which showed perfect fermentation. The glucose and maltose contents were higher in the domestic commercial brown rice vinegars. The organic acid content of the static-culture brown rice vinegar was similar to that of the Japanese brown rice vinegars. Therefore, the total acidity content, TN value, sensory property, and quality of the static-culture brown rice vinegar (A) were superior to those of the domestic and Japanese brown rice vinegars.

• Journal of Periodontal and Implant Science
• /
• v.29 no.1
• /
• pp.209-231
• /
• 1999

Even though titanium(Ti) and its alloys are the most used dental implant materials, there are some problems that Ti wears easily and interferes normal osteogenesis due to the metal ions. Ti coated with bioactive ceramics such as hydroxyapatite has also such problems as the exfoliation or resorption of the coated layer, Recent studies on implant materials have been proceeding to improve physical properties of the implant substrate and biocompatibility of the implant surfaces. The purpose of the present study was to examine the physical property and bone tissue compatibility of bioinert nitrides ion plated Ti, Button type specimens(14mm in diameter, 2.32rrun in height) for the abrasion test and cytotoxicity test and thread type implants(3.75mm in diameter, 6mm in length) for the animal experiments were made from Ti(grade 2) and 316LVM stainless steel. Ti specimens were ion plated with TiN, ZrN by the low temperature arc vapor deposition, and the depth profile of the TiN/Ti, ZrN/Ti ion plated surface was examined by Auger Electron Spectroscopy. Three kind of button type specimens .of TiN/Ti, ZrN/Ti and Ti were used for abrasion test, and HEPAlClC7 cells and CCD cells were cultivated for 4 days with the specimens for cytotoxicity test. Thread type implants of TiN/Ti, ZrN/Ti, Ti, 316LVM were implanted on the femur of 6 adult dogs weighing 10kg-13kg. Two dogs were sacrified for histological examination after 45 days and 90 days, and four dogs were sacrified for the removal torque test of the implant') after 90 days. The removal torque force was measured by Autograph (Shimadzu Co., AGS-1000D series, Japan). Abrasion resistance of TiN/Ti was the highest, and that of ZrN/Ti and Ti were followed. The bioinert nitride ion plated Ti had much better abrasion resistance, compared with Ti, In the cytotoxicity test, the number of both cells were increased in all specimens, and there were no significant difference in cytotoxic reaction among all groups (p>0.1), In histological examination, 316LVM showed the soft tissue engagement in interface between the implant and bone, but the other materials after 45 days noted immature new bone formation in the medullary portion along the implant surface, and those after 90 days showed implant support by new bone formation in both the cortical and the medullary portion, The removal torque force of Tilv/Ti showed significantly higher than that of Ti(p(O,05). The difference in removal torque force between TiN/Ti and ZrN/Ti was not significant(p>0.05), and that of 316LVM was lowest among all groups(p<0.05). These results suggest that bioinert nitrides ion plated Ti can resolve the existing problems of Ti and bioactive ceramics, and it may be clinically applicable to human.

• Journal of Convergence for Information Technology
• /
• v.10 no.10
• /
• pp.115-122
• /
• 2020

Due to the climate change, torrential rain downpours unprecedentedly, and urban areas repeatedly suffer from the inundation damages, which cause miserable loss of property and life by flooding. Two major reasons of urban flooding are river inundation and inland submergence. However, most of previous studies ignored the comprehensive mechanism of those two factors, and showed discrepancy and inadequacy due to the linear summation of each analysis result. In this study, river inundation and inland flooding were analyzed at the same time. Petrov-stabilizing scheme was adopted to capture the shock wave accurately by which river inundation can be modularized. In addition, flux-blocking alrotithm was introduced to handle the wet and dry phenomena. Sink/source terms with EGR (Exponentially Growth Rate) concept were incorporated to the shallow water equations to consider inland flooding. Comprehensive simulation implementing inland flooding and river inundation at the same time produced satisfactory results because it can reflect the counterbalancing and superposition effects, which provided accurate prediction in flooding analysis.

• Clean Technology
• /
• v.17 no.2
• /
• pp.85-96
• /
• 2011

Self-healing materials are a class of smart materials that have the structurally incorporated ability to repair damage caused by mechanical usage over time. A material (polymers, ceramics, metals, etc.) that can intrinsically correct damage caused by normal usage could lower production costs of a number of different industrial processes through longer part lifetime, reduction of inefficiency over time caused by degradation, as well as prevent costs incurred by material failure. The recent announcement from Nissan on the commercial release of scratch healing paints for use on car bodies has gained public interest on such a wonderful property of materials. This article is a second part of healing materials dealing with inorganic engineering materials such as metals, ceramics, and concrete. The healing mechanisms developed for the inorganic materials are to be discussed with the future prospect.

• Food Science of Animal Resources
• /
• v.35 no.1
• /
• pp.143-148
• /
• 2015

Yogurt powder is fermented milk processed in the form of dry yogurt, and has advantages such as stability, storability, convenience, and portability. China and Vietnam are important export target countries because of the increased demand for dairy products. Therefore, we surveyed dairy product standardization in order to establish an export strategy. Lactic acid bacteria counts are unregulated in Korea and Vietnam. In China, lactic acid bacteria counts are regulated at $1{\times}10^6$ colonyforming units (CFU)/mL and detected at $6.24{\pm}0.33\;Log\;CFU/mL$. All three countries have regulated standards for total bacterial counts. In China, total bacterial counts of milk powder are regulated to n=5, c=2, m=50,000, M=200,000 and detected at $6.02{\pm}0.12\;Log\;CFU/mL$, exceeding the acceptable level. Lactic acid bacterial counts appeared to exceed total bacterial counts. Coliform group counts, Staphylococcus aureus, Listeria monocytogenes, and Salmonella species were not detected. Acidity is not regulated in Korea and Vietnam. In China, acidity was regulated to over $70^{\circ}T$ and detected $352.38{\pm}10.24^{\circ}T$. pH is unregulated in all three countries. pH was compared to that of general fermented milk, which is 4.2, and that of the sample was $4.28{\pm}0.01$. Aflatoxin levels are not regulated in Korea and China. In Vietnam, aflatoxin level is regulated at 0.05 ppb. Therefore, all ingredients of the yogurt powder met the safety standards. This data obtained in this study can be used as the basic data in assessing the export quality of yogurt powder.

• Journal of the Korean Geotechnical Society
• /
• v.21 no.2
• /
• pp.57-65
• /
• 2005

Geotextile have been used for the past 30 years for various types of containers, such as small sandbag, 3-D fabric forms and aggregate filled gabion etc. While they are mainly used for flood and water control, they are also used against beach erosion fir shore protection. Especially, large-sized geotextile tube structures are used in various innovative coastal systems involving breakwaters. This paper presents the hydrodynamic behavior of geotextile tubes based on the results of hydraulic model tests. These tube are generally about 1.0 m to 2.0 m in diameter, thou띤 they can be sized for any application. The tubes can be used solely, or stacked to add greater height and usability. Stacked geotextile tubes will be created by adding the height necessary for some breakwaters and embankment, therefore increasing the usability of geotextile tubes. The hydraulic model test was conducted as structural condition and wave conditions. Structural condition is installation direction to the wave (perpendicular and 45$^{circ}$$), and wave condition is varied with the significant wave height ranging from 3.0 m to 6.0 m. Compared with previous test result, the stacked geotextile tube is more stable against wave attack than single tube. Also, the case of none-water depth above crest is more stable than 0.5H of water depth above crest. The incline installed stacked tube is more effective for wave adsorption.

• Journal of the Korean Vacuum Society
• /
• v.21 no.6
• /
• pp.301-311
• /
• 2012

Discharge property of plasma jet devices is investigated for the application to the doping processes of crystalline solar cells and others. Current-voltage characteristics are shown as the typical normal-glow discharge in the various gas pressure of plasma jets, such as in the atmospheric plasma jets of Ar-discharge, in the ambient pressure of atmospheric discharge, and in the ambient Ar-pressure of Ar-discharge. The discharge voltage of atmospheric plasma jet is required as low as about 2.5 kV while the operation voltage of low pressure below 200 Torr is low as about 1 kV in the discharge of atmospheric and Ar plasma jets. With a single channel plasma jet, the irradiated plasma current on the doped silicon wafer is obtained high as the range of 10~50 mA. The temperature increasement of wafer is normally about $200^{\circ}C$. In the result of silicon wafers doped by phosphoric acid with irradiating the plasma jets, the doping profiles of phosphorus atoms shows the possibility of plasma jet doping on solar cells.