• Journal of Soil and Groundwater Environment
• /
• v.12 no.4
• /
• pp.54-59
• /
• 2007

In this study, a semi-analytical model to address groundwater level fluctuations in response to precipitations and its infiltration is developed through mathematical modeling based on water balance equation. The developed model is applied to a prediction of groundwater level fluctuations in Hongcheon area. The developed model is calibrated through a nonlinear parameter estimator by using daily precipitation rates and groundwater fluctuations data of a same year 2003. The calibrated input parameters are directly applied to the prediction of groundwater fluctuations of year 2004 and the simulated curve successfully mimics the observed. The developed model is also applied to practical problems such as a prediction of a effect of reduced recharge due to surface coverage change and a induced water level reduction. Through this study, we found that recharge to precipitation ratio is not a constant and may be a function of a precipitation pattern.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.41 no.2
• /
• pp.1-6
• /
• 2009

The purpose of this study was to investigate effects of lignocellulosic fillers made of wood powder and inorganic fillers, such as GCC and PCC, on physical properties of papers. Mechanical treatment and chemical treatment were carried out subsequently for generating lignocellulosic fillers, and then inorganic filler and wood powder were mixed together, and then mechanically treated for making lignocellulosic fillers covered with inorganic fillers. Consequently the particle size of lignocellulosic fillers was higher than that of inorganic fillers, which led to lumen loading and simultaneously surface coverage of fine inorganic fillers. Lignocellulosic fillers contributed to the increase of both bulk and opacity of handsheets dramatically, but some of properties including tensile strength, brightness and roughness decreased compared to inorganic fillers.

• Horticultural Science & Technology
• /
• v.33 no.3
• /
• pp.340-348
• /
• 2015

Mowing turfgrasses, especially fast growing species like perennial ryegrass, is one of the most time and money consuming tasks of their management. Trinexapac-ethyl (TE) is a popular plant growth regulator used to reduce mowing requirements, improve stress tolerance, and enhance turf quality. This study was conducted to investigate the effect of TE rate and frequency of applications on growth response and traffic tolerance of perennial ryegrass. The experiment was a split-plot laid out in a randomized complete block (RCB) design with three replications. TE was applied to main plots at 0.00, 0.25, and $0.50kg\;a.i.\;ha^{-1}$. Application pattern included an initial application, followed by two sequential applications at 6-wk intervals. Traffic treatment was applied to subplots with a cleated roller. Results demonstrated that TE consistently reduced vertical shoot growth, clippings dry weight, with maximum growth reduction of 59% and 65%, for 0.25 and $0.50kg\;a.i.\;ha^{-1}$, respectively, occurring at 2 weeks after initial TE treatment (WAT). Traffic also dramatically reduced vertical shoot growth and clippings dry weight. Overall, quality of perennial ryegrass was enhanced by sequential TE applications, however, turf quality and surface coverage reduced greatly under traffic, regardless of TE treatment. Total chlorophyll, chlorophyll a and chlorophyll b and total carbohydrates (TC) contents were also positively influenced following sequential TE application. Our results indicated that TE reduces mowing frequency and enhances turf quality rather than influencing traffic resistance.

• Journal of the Microelectronics and Packaging Society
• /
• v.24 no.3
• /
• pp.57-62
• /
• 2017

In the process for preparing Ag-coated Cu flakes by electroless silver plating using hydroquinone reducing agent, Ag coating qualities were compared by changing various process parameters such as type of pretreatment solution, plating temperature, pH of plating solution, type and injection rate of plating solution, and pulp density. Effective pretreatment solution for removing the oxide layer on a Cu flake was preferentially suggested. The conditions of low plating temperature, pH value of 4.34, slow injection rate of Ag plating solution, elimination of deionized water in the Ag plating solution, and high pulp density significantly suppressed the formation of separated tiny Ag particles, and thus the surface coverage of Ag coating on Cu flakes was enhanced.

• Korean Journal of Childcare and Education
• /
• v.16 no.4
• /
• pp.73-92
• /
• 2020

Objective: The purpose of this study is to examine occupational safety accidents of child care teacher and to suggest preventive measure in occupational safety health and safety for child-care teacher. Methods: We investigated laws, policy, and previous studies related occupational safety and health for child care teacher. Especially, we reviewed the legal definition of child-care teacher to identify whether Occupational Safety and Health acts cover child-care teacher. Also cross tabulation and a qualitative analysis were conducted for occupational accidents in child care centers from 2013-2018. Results: Safety and health related policies to protect child care centers have been carried out by child care Center Safety and Insurance Association and the Child Care Support Center, but it has mainly been functioned to protect children excluding child care teacher. The most occupational accidents occur in worker aged 40s. The most type of occupational accident were falling down on the floor and surface. Also we could find that there is a high risk of falls, and musculoskeletal disorders through qualitative analysis on occupational accidents cases of child-care teacher. Conclusion/Implications: We suggest to improve the system for protecting child care workers including strengthening occupational safety and health education for child care workers, expanding coverage of national project to prevent occupational accidents.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.18 no.6
• /
• pp.215-226
• /
• 2015

This study introduced food waste into re-vegetation base materials for surface loss recovery of carry-away highway cut slope. The object of this study is to derive the mixing ratio of food waste by conducting a test installation, monitoring, analysis and evaluation for recovery of carry-away highway cut slope. The following items were investigated and analyzed each experimental zone to draw mixing ratio of re-vegetation base materials and food waste : the physical and chemical properties of the vegetation base materials, soil-hardness, soil-humidity, left out and the collapsed point, established number of trees, species richness of grass species and tree species, coverage, pest status, and invasion of disturbance species. The re-vegetation method was evaluated by each experiment zone which has different mixing ratio. As a result, experiment zone A was rated 45 points out of 60 rating points as the best re-vegetation method. However, this study result has been derived from one construction and short-term monitoring. In order to derive the suitable and dependable mixing ratio, conducting an objective re-vegetation method evaluation and long-term experiment and monitoring is required.

• Archives of Plastic Surgery
• /
• v.45 no.6
• /
• pp.504-511
• /
• 2018

Background Acellular dermal matrix (ADM) helps wound healing by stimulating angiogenesis, acting as a chemoattractant for endothelial cells, providing growth factors, and permitting a substrate for fibroblasts to attach. The current standard for using paste-type ADM (CG Paste) in wound healing is direct application over the wounds. The major concerns regarding this method are unpredictable separation from the wounds and absorption into negative-pressure wound therapy devices. This study aimed to investigate the effects of subcutaneous injection of paste-type ADM on wound healing in rats. Methods Full-thickness skin defects were created on the dorsal skin of rats. Eighteen rats were randomly divided into three groups and treated using different wound coverage methods: group A, with a saline dressing; group B, standard application of CG Paste; and group C, injection of CG Paste. On postoperative days 3, 5, 7, 10, and 14, the wound areas were analyzed morphologically. Histological and immunohistochemical tissue analyses were performed on postoperative days 3 and 7. Results Groups B and C had significantly less raw surface than group A on postoperative days 10 and 14. Collagen fiber deposition and microvessel density were significantly higher in group C than in groups A and B on postoperative days 3 and 7. Conclusions This study showed comparable effectiveness between subcutaneous injection and the conventional dressing method of paste-type ADM. Moreover, the injection of CG Paste led to improved wound healing quality through the accumulation of collagen fibers and an increase in microvessel density.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.32 no.4
• /
• pp.88-94
• /
• 2004

The electrical design of the Ka-band antenna for the domestic Communications and Broadcasting Satellite (CBS) is described. The antenna has the offset Gregorian structure and is installed on the Earth-facing panel of the satellite. The electrical performance specifications for the antenna were determined from the required EIRP and G/T through the payload level performance analysis. This paper utilized the reflector shaping technology for the trade-off among the major performance parameters, resulting in compliance of all the parameters. The designed antenna shows 37.95 dBi EOC (End of Coverage) gain and 28.7 dB sidelobe isolation for transmit band, and 37.49 dBi EOC gain and 31.1 dB sidelobe isolation for receive band, The electrical performances of the antenna have been verified via the electrical testing of a manufactured EQM (Engineering Qualification Model) antenna.

• Journal of Ecology and Environment
• /
• v.33 no.4
• /
• pp.377-389
• /
• 2010

Understanding the factors relevant to endangerment and the patterns of habitat locations in relation to protected areas is critically important for the conservation of rare species. Although 64 plant species have recently been listed as endangered species in Korea, this information has, until now, not been available, making appropriate management and conservation strategies impossible to devise. Thus, we collected information on potentially threatening factors, as well as information on the locations in which these species were observed. The potentially threatening factors were classified into seven categories. National parks, provincial parks, ecosystem conservation areas, and wetland conservation areas were defined as protected conservation areas. Korean digital elevation model data, along with the maps of all protected areas were combined with the maps of endangered plant species, and analyzed via Geographic Information Systems (GIS). Excluding the category of "small population", endangered plant species in Korea were associated more frequently with extrinsic factors than intrinsic factors. Considering land surface only, all conservation areas in Korea totaled 4.9% of the land, far lower than International Union for Conservation of Nature and Natural Resources (IUCN)'s 10% coverage target. At the species level, 69% of the endangered plant species were detected in conservation areas, mostly in national parks. However, this result demonstrates that 31% of endangered species inhabit areas outside the conservation zones. Furthermore, at the habitat level, a large proportion of endangered species were found to reside in unprotected areas, revealing "gaps" in protected land. In the face of rapid environmental changes such as population increases, urbanization, and climate changes, converting these gap areas to endangered species' habitats, or at least including them in habitat networks, will help to perpetuate the existence of endangered species.

• Korean Chemical Engineering Research
• /
• v.54 no.6
• /
• pp.734-745
• /
• 2016

This review article described the electrochemical Frumkin, Langmuir, and Temkin adsorption isotherms of over-potentially deposited hydrogen (OPD H) and deuterium (OPD D) for the cathodic $H_2$ and $D_2$ evolution reactions (HER, DER) at Pt, Ir, Pt-Ir alloy, Pd, Au, and Re/normal ($H_2O$) and heavy water ($D_2O$) solution interfaces. The Frumkin, Langmuir, and Temkin adsorption isotherms of intermediates (OPD H, OPD D, etc.) for sequential reactions (HER, DER, etc.) at electrode/solution interfaces are determined using the phase-shift method and correlation constants, which have been suggested and developed by Chun et al. The basic procedure of the phase-shift method, the Frumkin, Langmuir, and Temkin adsorption isotherms of OPD H and OPD D and related electrode kinetic and thermodynamic parameters, i.e., the fractional surface coverage ($0{\leq}{\theta}{\leq}1$) vs. potential (E) behavior (${\theta}$ vs. E), equilibrium constant (K), interaction parameter (g), standard Gibbs energy (${\Delta}G_{\theta}{^{\circ}}$) of adsorption, and rate (r) of change of ${\Delta}G_{\theta}{^{\circ}}$ with ${\theta}$ ($0{\leq}{\theta}{\leq}1$), at the interfaces are briefly interpreted and summarized. The phase-shift method and correlation constants are useful and effective techniques to determine the Frumkin, Langmuir, and Temkin adsorption isotherms and related electrode kinetic and thermodynamic parameters (${\theta}$ vs. E, K, g, ${\Delta}G_{\theta}{^{\circ}}$, r) at electrode/solution interfaces.