• Journal of Radiation Industry
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• v.7 no.1
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• pp.29-35
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• 2013

Microbiological populations and the sterility of commercial powdered products treated with gamma irradiation at 0~10 kGy were investigated before using them as ingredients for a non-cooked Saengsik product. We evaluated a total of 14 powdered products: 8 powdered cereals, 3 powdered tubers, and 3 powdered leafy vegetables. The total numbers of bacterial populations in non-irradiated powdered cereals, tubers, and leafy vegetables were 2.7~6.9, 5.6~6.0, and $5.3{\sim}6.8\;log\; CFU{\cdot}g^{-1}$, respectively. Moreover, coliform bacteria were not indicated in adlay, millet, germinated brown rice, soybean, and mulberry leaves powder within detection limit ($2.0\;log\; CFU{\cdot}g^{-1}$). The number of Bacillus cereus exceeded $3.0\;log\; CFU{\cdot}g^{-1}$ (the maximum limit for Saengsik products) in all samples, excluding perilla seeds, buckwheat, barley, oat, potato, and Jerusalem artichoke powder. However, a dose of 6 kGy of gamma irradiation reduced the microbiological populations in all samples, and all the powdered products met the microbial requirements for Saengsik products. Futhermore, it was confirmed that all microorganisms in the 9 powdered products, except fermented brown rice, sweet potatoes, and 3 leafy vegetables, were sterilized by 10 kGy of gamma irradiation.

• Journal of Climate Change Research
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• v.6 no.4
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• pp.357-366
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• 2015

This study was conducted to estimate carbon stocks of Quercus serrata with drawing volume of trees in each tree height and DBH applying the suitable stem taper equation and tree specific carbon emission factors, using collected growth data from all over the country. Information on distribution area, tree number per hectare, tree volume and volume stocks were obtained from the $5^{th}$ National Forest Inventory (2006~2010), and method provided in IPCC GPG was applied to estimate carbon storage and removals. Performance in predicting stem diameter at a specific point along a stem in Quercus serrata by applying Kozak's model,$d=a_1DBH^{a_2}a_3^{DBH}X^{b_1Z^2+b_2ln(Z+0.001)+b_3{\sqrt{Z}}+b_4e^Z+b_5({\frac{DBH}{H}})}$, which is well known equation in stem taper estimation, was evaluated with validations statistics, Fitness Index, Bias and Standard Error of Bias. Consequently, Kozak's model turned out to be suitable in all validations statistics. Stem volume tables of Quercus serrata were derived by applying Kozak's model and carbon stock tables in each tree height and DBH were developed with country-specific carbon emission factors ($WD=0.65t/m^3$, BEF=1.55, R=0.43) of Quercus serrata. As a result of carbon stock analysis by age class in Quercus serrata, carbon stocks of IV age class (11,358 ha, 36.5%) and V age class (10,432; 33.5%) which take up the largest area in distribution of age class were 957,000 tC and 1,312,000 tC. Total carbon stocks of Quercus serrata were 3,191,000 tC which is 3% compared with total percentage of broad-leaved forest and carbon sequestration per hectare(ha) was 3.8 tC/ha/yr, $13.9tCO_2/ha/yr$, respectively.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.6
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• pp.739-745
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• 2017

Many studies have been conducted to reduce environmental pollution by ships and reduce fuel consumption. As part of this effort, research on power conversion systems through DC distribution systems that link renewable energy with conventional power grids has been pursued as well. The diode rectifiers currently used include many lower harmonics in the input current of the load and distort supply voltage to lower the power quality of the whole system. This distortion of voltage waveforms causes the malfunctions of generators, load devices and inverter pole switching elements, resulting in a large number of switching losses. In this paper, a controller is presented to improve DC output waveforms, the input Power Factor and the THD of an AFE type PWM rectifier used for PLL. DC output voltage waveforms have been improved, and the input Power Factor can now be matched to the unit power factor. In addition, the THD of the input power supply has been proven by simulation to comply with the requirements of IEEE Std514-2014.

• Journal of Adhesion and Interface
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• v.12 no.3
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• pp.88-93
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• 2011

Optimal dispersion and fabrication conditions of carbon nanotube (CNT) embedded in phenolic resin were determined by electrical resistance measurement; and interfacial property was investigated between plasma treated carbon fiber and CNT-phenolic composites by electro-micromechanical techniques. Wettability of carbon fiber was improved significantly after plasma treatment. Surface energies of carbon fiber and CNT-phenolic nanocomposites were measured using Wilhelmy plate technique. Since surface activation of carbon fiber, the advancing contact angle decreased from $65^{\circ}$ to $28^{\circ}$ after plasma treatment. It was consistent with static contact angle results of carbon fiber. Work of adhesion between plasma treated carbon fiber and CNT-phenolic nanocomposites was higher than that without modification. The interfacial shear strength (IFSS) and apparent modulus also increased with plasma treatment of carbon fiber.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.4 s.54
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• pp.311-321
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• 2005

Tea (Camellia sinenis) is a popular beverage consumed worldwide. Since green tea, mainly consumed in Asia, has various biological activities, green tea components became one of the most favorite candidates as a functional materials for cosmetics and functional foods. The biological activities of green tea for skin cue have been ranged from protection of epidermal cells to the stimulation of extracellular matrix (ECM) biosynthesis. Green tea polyphenols (GTPs), which are active ingredients of green tea, possess anti-inflammatory, anti-carcinogenic and immune potentiation properties as well as antioxidant. They also modulate intracellular signal transduction pathways. GTPs decrease ultraviolet (UV)-induced oxidative stress, thus suppress mitogen-activated protein kinase (MAPK) pathway and apoptosis in keratinocytes. In addition, GTPs prevent the Induction of inflammatory mediators, such as cyclooxygenase-2 (COX-2), interleukin-8 (IL-8), and vascular endothelial growth factor (VEGF) by tumor necrosis factor alpha $(TNF{\alpha})$ or chemical treatment in keratinocytes. GTPs treatment protects from chemical-or UV-induced skin tumor incidence in animal experiment. Besides, GTPs stimulate keratinocyte differentiation and proliferation of normal and aged epidermal cells, resectively, and suppress matrix metalloproteinases (MMPs) release. According to the progress of formulation study, green tea components will be guaranteed materials for the more effective skin cue products.

• Polymer(Korea)
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• v.34 no.4
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• pp.363-368
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• 2010

Adequate acidic environment in wound healing prevents the inflammation of virus, increases the cell activity, promotes cell proliferation and regular rearrangement of fibroblast, and results in matured epithelialization. In this study, we prepared dressing materials consisting of pectin and carboxymethylcellulose (CMC) with varied ratios. These dressing materials showed different pH values according to the composition ratio. The effect of acidity of pectin/CMC dressing materials on wound healing rates, degree of epithelialization, collagen deposition, and so on, in 3 types of wound models (fresh surgical wounds, $3^{rd}$ degree burn wounds, and infection wounds) were investigated by animal tests. From the results of wound contraction, wound healing, and epithelialization, it can be deduced that dressing material having pectin/CMC ratio of 16/19 (pH 4.67) is most effective among the 3 types of wound models.

• Korean Journal of Optics and Photonics
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• v.19 no.4
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• pp.294-301
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• 2008

We have performed modeling and simulations of optical characteristics for a cholesteric liquid crystal (CLC) color filter. Berreman's $4{\times}4$ matrix method was used for the calculation of reflectance spectra of the CLC color filter with respect to the incident angle. The results were employed as input parameters for a user-defined coating property of an illumination design software based on the ray-tracing method, LightTools. Color shift characteristics of a planar transmission-type CLC color filter were simulated using LightTools. The results were compared with the results obtained with Berreman's $4{\times}4$ matrix method. It was found that color shift characteristics of the CLC color filter could be simulated to a reasonable accuracy when the reflectance spectra with less than 5 degrees of incremental incidence-angle were used as the input data for the user-defined coating property of LightTools. We have simulated color shift characteristics of a reflection-type CLC color filter having hemi-spherical patterns. The simulation method reported in this paper has been found to be also used for a non-planar CLC color filter structure.

• Current Optics and Photonics
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• v.1 no.1
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• pp.51-59
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• 2017

In addition to its typical use for skin rejuvenation, fractional laser irradiation of early cancerous lesions may reduce the risk of tumor development as a byproduct of wound healing in the stroma after the controlled injury. While fractional ablative lasers are commonly used for cosmetic/aesthetic purposes (e.g., photorejuvenation, hair removal, and scar reduction), we propose a novel use of such laser treatments as a stromal treatment to delay tumorigenesis and suppress carcinogenesis. In this study, we found that non-ablative fractional laser (NAFL) irradiation may have a possible suppressive effect on early tumor growth in syngeneic mouse tumor models. We included two syngeneic mouse tumor models in irradiation groups and control groups. In the irradiation group, a thulium fiber based NAFL at 1927 nm was used to irradiate the skin area including the tumor injection region with 70 mJ/spot, while no laser irradiation was applied to the control group. Numerical simulation with the same experimental condition showed that thermal damage was confined only to the irradiation spots, sparing the adjacent tissue area. The irradiation groups of both tumor models showed smaller tumor volumes than the control group at an early tumor growth stage. We also detected elevated inflammatory cytokine levels a day after the NAFL irradiation. NAFL treatment of the stromal tissue could potentially be an alternative anticancer therapeutic modality for early tumorigenesis in a minimally invasive manner.

• Journal of Forest and Environmental Science
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• v.27 no.2
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• pp.101-111
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• 2011

The Returning Land for Farming to Forestry Project in China is similar to the 'The 10-year National Greening Project' of Korea, and is one of the great strategic policies that started in order to develop the people, resources and the environment by the central government of China. Using the ecosystem recovery as the slogan, The Returning Land for Farming to Forestry Project of China has a long history of 70 years, but the accomplishments has been insignificant when compared to the long history. The Returning Land for Farming to Forestry Project was not a trend due to the societal and economical issues of China, but with the increasing interest on the environmental protection in the late 1990s the extent of the ecosystem is gradually increasing. The most difficult, yet most important matter of the Returning Land for Farming to Forestry Project, is that it must consider the ecosystem with the economy. The farmers want financial gains in a short term, and the government aims is gaining cost-benefit over a long period which is why a rational the Returning Land for Farming to Forestry Project of the central government in China is most important. In order for the Returning Land for Farming to Forestry Project of China to develop further in the future, the standardization and distinction of the economic compensation policy is most urgent. Other than this, a new policy and the government interest on the livelihood of the farmers after the completion of the Returning Land for Farming to Forestry Project are needed, and there must be a clear and fair policy enactment environment so that the opinions of the farmers can influence the policy in the policy enactments.

• Journal of Korea Foundry Society
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• v.41 no.5
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• pp.411-418
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• 2021

In order to experimentally investigate the effect of Ni or Cu addition on microstructure and mechanical properties of high Si Solution Strengthened Ferritic Ductile cast Iron (SSF DI), a series of lab-scale sand casting experiment were conducted by changing initial concentration of Ni up to 3.0wt% or Cu up to 0.9wt% in the alloy. It was found that increase in Ni or Cu content in the alloy leads to increase in strength properties and hardness as well as decrease in ductility. The higher Ni or Cu content the SSF DI has, the higher fraction of pearlite was observed. At similar levels of Ni or Cu contents in the alloy, higher pearlite area fraction was observed in the Cu-containing SSF DI than that in the Ni-containing SSF DI. When the effect of the microstructure on the mechanical properties of Ni-containing SSF DI was considered, Ni-containing SSF DI was found to have excellent strength and hardness as well as good elongation when the pearlite fraction was controlled less than 10%. As the pearlite fraction in the Ni-containing SSF DI exceeds 10%, however, it shows drastic decrease in elongation. Meanwhile, gradual increase in strength and hardness, and decrease in elongation with respect to increase in pearlite fraction were observed in Cu-containing SSF DI. The different microstructure-mechanical property relationships between Ni-containing and Cu-containing SSF DI were due to the combined effect of the relatively weak pearlite stabilizing effect of Ni compared to that of Cu in high Si SSF DI, and matrix strengthening effect caused by the different amounts of those alloying elements required for similar pearlite fraction.