• Journal of Korean Ophthalmic Optics Society
• /
• v.3 no.1
• /
• pp.93-101
• /
• 1998

The present study was conducted to investigate the structural changes in rat cornes. Sixty eyes from one-day-old uneyed rats, fourty eyes from 10-weeks-old adult rats were used. With the increase of age, the epithelial layer was thickened by the addition of new successive cellular layers. Then, the new-born rat's epithelial cells formed a pentagonal shape, and the quality of decidual cells showed a high electron-density, although the boundary between cells was distinctive. The newly produced cells showed a low electron-density so that there was the distinctive difference between light and darkness. In Bowman's layer, collagen fibrils demonstrate a regularly arranged structure along with the age. In stroma's layer, the density of keratocytes was decreased and thereby progressively flattened during the development. The collagenous layer of the adult rats was more distinctive than that of the new-born rats in a form of vertical and horizontal parallel alignment running vertically and horizontally. Descemet's membrane changed its structure significantly along with the age. It changed the shape from "banded-layer" to "non-banded layer" gradually. The thickness was also increased along with the age. Regardless of developmental stages, the endothelium is usually monolayer. During the developmental process, endothelial cells disappeared, so the density of endothelium was also decreased. The empty spaces were replaced by the expansion of adjacent cells.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.25 no.1
• /
• pp.23-33
• /
• 2017

In this study, water and organic treatment efficiency and operating characteristics (temperature, salinity effect) were evaluated when food waste with high water content was treated by Bio-dying method. In addition, the optimum conditions for producing pellets for evaluating the decomposition products as SRF(Solid Refuse Fuel) after Bio-drying and evaluating the use value of SRF as a solid fuel were analyzed. As a result, the temperature, $CO_2$ concentration, organic matter removal rate and weight reduction rate according to the daily dose were about 86% and 68% at the input of 2.4 kg/day. The optimal food waste input was estimated to be 2.4 kg/day. As a result of the pellet molding and produce, Pellets can be produced within 10~25% of raw material water content. It was judged that the water content of 25%, which showed the best quality results in terms of external shape maintenance and strength. The high calorific value of SRF of decomposition products after Bio-drying was more than 3,500 kcal/kg.

• The Korean Journal of Rheology
• /
• v.10 no.4
• /
• pp.217-226
• /
• 1998

The anisotropy caused by the fiber orientation, which is inevitably generated by the flow during injection molding of short fiber reinforced polymers, greatly influences dimensional accuracy, mechanical properties, and other quality of the final product. Since the filling stage of the injection molding process plays a vital role in determining fiber orientation, an accurate analysis of flow field for the filling stage is needed. Unbalanced filling occurs when a complex or a multi-cavity mold is used leading to development of regions where the fiber suspension is under compression. It is impossible to make an accurate calculation of the flow field during filling with the analysis assuming incompressible fluid. A mold with four cavities with different filling times was produced to compare the numerical analysis results with the experimental data. There was a good agreement between the experimental and theoretical results when the compressibility of the polymer melt was considered for the numerical simulation. The fiber orientation states for compressible and incompressible fluids were also compared qualitatively as well as quantitatively in this study.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.6
• /
• pp.955-960
• /
• 2012

In most agricultural soils, ammonium ($NH_4{^+}$) from fertilizer is quickly converted to nitrate ($NO_3{^-}$) by the process of nitrification which is crucial to the efficiency of N fertilizers and their impact on the environment. The salinity significantly affects efficiency of N fertilizer in reclaimed tidal soil, and the soil pH may influence the conversion rate of ammonium to nitrate and ultimately affect nitrogen losses from the soil profile. Several results suggest that pH has important effects on recovery of fall-applied N in the spring if field conditions are favorable for leaching and denitrification except that effects of soil pH are not serious under unfavorable conditions for N loss by these mechanisms. Soil pH, therefore, deserves attention as an important factor in the newly reclaimed tidal soils with applying N. However, fate of N studies in a newly reclaimed tidal soils have been rarely studied, especially under the conditions of saline-sodic and high pH. Therefore, understanding the fate of nitrogen species transformed from urea treated into the reclaimed tidal soil is important for nutrient management and environmental quality. In this article, we reviewed yields of rice and fate of nitrogen with respect to the properties of reclaimed tidal soils.

• Therapeutic Science for Rehabilitation
• /
• v.7 no.1
• /
• pp.63-77
• /
• 2018

Objective : The purpose of this study was to investigate the effects of task-oriented training with functional electrical stimulation on hand function in incomplete cervical cord injury. Method : The subjects of the study were 3 adults diagnosed as incomplete cervical cord injury. The design of this study was ABA single-subject research design to compare dominant hand function of before and after intervention and detect individual effects. The experiment consisted of 30sessions, in which baseline process A1 and A2 were implemented 5 sessions each for 10sessions. Intervention B was implemented 20 sessions. The dependent variable was converted to the change of hand function every session, and Canadian Occupational Performance Measure (COPM), Jebsen-Taylor Hand Function Test(JTHFT), Wolf Motor Function Test(WMFT) were selected for outcome measurements. Result analysis was suggested through visual analysis using a graph and comparison of pre, post and follow-up intervention measurements. Results : As a result, the quality and quantity of dominant hand function increased during intervention B compared to the baseline A1 for all subjects. Baseline A2 was also maintained without training. Additionally, JTHFT, WMFT and COPM scores demonstrated improvement and maintain. The follow up JTHFT and WMFT showed increased required time on all subjects and decrease or maintain task performance and satisfaction in COPM. Conclusion : The task-oriented training with function electrical stimulation in this study has been positive effects on hand function and task performance and satisfaction.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.345-346
• /
• 2013

InGaN material is being studied increasingly as a prospective material for solar cells. One of the merits for solar cell applications is that the band gap energy can be engineered from 0.7 eV for InN to 3.4 eV for GaN by varying of indium composition, which covers almost of solar spectrum from UV to IR. It is essential for better cell efficiency to improve not only the crystalline quality of the epitaxial layers but also fabrication of the solar cells. Fabrication includes transparent top electrodes and surface texturing which will improve the carrier extraction. Surface texturing is one of the most employed methods to enhance the extraction efficiency in LED fabrication and can be formed on a p-GaN surface, on an N-face of GaN, and even on an indium tin oxide (ITO) layer. Surface texturing method has also been adopted in InGaN-based solar cells and proved to enhance the efficiency. Since the texturing by direct etching of p-GaN, however, was known to induce the damage and result in degraded electrical properties, texturing has been studied widely on ITO layers. However, it is important to optimize the ITO thickness in Solar Cells applications since the reflectance is fluctuated by ITO thickness variation resulting in reduced light extraction at target wavelength. ITO texturing made by wet etching or dry etching was also revealed to increased series resistance in ITO film. In this work, we report a new way of texturing by deposition of thickness-optimized ITO films on ITO nano dots, which can further reduce the reflectance as well as electrical degradation originated from the ITO etching process.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.48 no.3
• /
• pp.196-199
• /
• 2003

This experiment was conducted to evaluate the differences in physicochemical properties of soil, grain yield and milling recovery ratio and grain appearance of rice grown in long-term no-till and ordinary till systems. The paddy in no-till rice system was unploughed but straw-mulched for 15 years from 1988 to 2002 at the Experimental Paddy of Gyeongnam Agricultural Research and Extension Services, while the paddy in ordinary till system was ploughed and puddled every crop year, A 5cm organic layer was formed in 11-year no-till rice system, in which exchangeable cation and phosphate were accumulated. In no-till paddy organic matter, bulk density and solid phase of surface soil significantly increased, while pH, exchangeable cation, phosphate, liquid and gaseous phase decreased. Tillage made the very top soil soft, but made deep soil below 5cm significantly hard. In the 1st year of no-till, topsoil showed hard, but in the process of the time in no-till system, the top- and sub-soil showed softer, Yield and yield components of rice showed no differences between till- and no-till rice systems. Milling recovery ratio and grain appearance were not significantly different between no-till and till-rice systems.

• Journal of Korean society of Dental Hygiene
• /
• v.10 no.3
• /
• pp.513-522
• /
• 2010

Objectives : This study aimed to determine self-esteem and oral health impact profile (OHIP) of orthodontic patients to get data necessary for the process of consultation, education, and treatment for those patients who hoped to get orthodontic therapy in order to see effects of orthodontic therapy on personal life in consideration of general characteristics of those patients under orthodontic therapy. methods : A self-administered questionnaire was used among 232 outpatients under orthodontic therapy from October to November 2009, obtaining the following results. Results : 1. As for general characteristics of respondents, those under 19 years of age constituted 46.6%; the unmarried comprised 85.8%; and students constituted 53.4%. 2. Most respondents were getting orthodontic therapy for beauty (41.8%) and dental health (40.5%). Family (54.3%) contributed to their decision to get orthodontic therapy; parents or siblings (62.5%) were bearing the treatment expenses. 3. Females were getting orthodontic therapy for an aesthetic purpose (50.3%), and male for the purpose of dental health (44.6%) (P<0.01). 4. OHIP was slightly higher among males ($4.10{\pm}0.61$) than among female ($4.00{\pm}0.78$), and was highest among those 19 years old and under ($4.17{\pm}0.67$); the older they were, the lower it was significantly (P<0.05). Most of them were earning 3 to 4 million won ($4.22{\pm}0.72$); the married ($4.05{\pm}0.74$) constituted higher percentage. As for occupation, students ($4.13{\pm}0.66$) comprised the highest percentage. 5. Self-esteem was higher among males ($3.83{\pm}0.47$) than among females ($3.80{\pm}0.50$), and was highest among those 25 to 29 years old ($3.92{\pm}0.46$). Most of them were earning more than 5 million won ($3.91{\pm}0.42$), which was statistically significant (P<0.01). The married ($3.91{\pm}0.54$) constituted higher percentage than the unmarried ($3.80{\pm}0.48$); office managers ($3.95{\pm}0.55$) comprised the highest percentage. 6. As for correlation between variables effecting OHIP of orthodontic patients, there was negative correlation in age (r=-0.225) and positive correlation in occupation (r=0.122). As for correlation between variables effecting self-esteem of orthodontic patients, there was negative correlation in occupation (r=-0.130) and positive correlation n income (0.126), while there was positive correlation (r=0.202) between OHIP and self-esteem of orthodontic patients. Conclusions : Younger orthodontic patients who were students showed higher OHIP, and professionals earning more showed higher self-esteem. Orthodontic patients with higher OHIP showed higher self-esteem. Therefore, it is necessary to develop a program based on OHIP and self-esteem in consulting and treating orthodontic patients; since it is considered that orthodontic therapy will improve appearance, enhance self-confidence, and have positive effects on interpersonal relationships and quality of living, researches are necessary on constant changes in psychological properties.

• Journal of Korean Society for Atmospheric Environment
• /
• v.33 no.3
• /
• pp.191-204
• /
• 2017

Concerns on the air pollution problem caused by ambient fine particles have become a big social issue in Korea. Important factors that should be addressed to develop effective and efficient air quality management policy, especially, against fine particles are discussed and research and policy directions to address these factors are suggested. It is suggested that two factors are in high priority; one is scientific understanding of the major formation mechanisms of fine particles and the other is the process of policy decision and implementation. For the scientific understanding, smog chamber measurement, intensive field study, and chemical transport model development that can simulate the characteristics of Northeast Asia are considered to be important. For the policy directions, priority setting of the proposed policies and development and implement of effective communication sytem are considered to be important.

• Journal of Korean Society for Atmospheric Environment
• /
• v.32 no.5
• /
• pp.536-546
• /
• 2016

The diurnal variations of $O_3$ and $NO_2$ in an urban park and the effects of air temperature and wind speed on the diurnal variations are investigated. $O_3$ and $NO_2$ concentrations were observed at a site in an urban park of Seoul from 27 July 2015 to 9 August 2015. The $O_3$ and $NO_2$ concentrations observed in the urban park are compared to those observed at the Gangnam air quality monitoring station (AQMS). The $O_3$ concentration is higher in the urban park than at the Gangnam AQMS in the daytime because the amount of $O_3$ dissociated by NO is smaller as well as partly because the amount of $O_3$ produced in the oxidation process of biogenic volatile organic compounds (VOCs) is larger in the urban park than at the Gangnam AQMS. The $NO_2$ concentration is lower in the urban park than at the Gangnam AQMS during day and night because the observation site in the urban park is relatively far from roads where $NO_x$ is freshly emitted from vehicles. The difference in $NO_2$ concentration is larger in the daytime than in the nighttime. To examine the effects of air temperature and wind speed on the diurnal variations of $O_3$ and $NO_2$, the observed $O_3$ and $NO_2$ concentrations are classified into high or low air temperature and high or low wind speed days. The high $O_3$ and $NO_2$ concentrations in the daytime appear for the high air temperature and low wind speed days. This is because the daytime photochemical processes are favorable when the air temperature is high and the wind speed is low. The scatter plots of the daytime maximum $O_3$ and minimum $NO_2$ concentrations versus the daytime averages of air temperature and wind speed show that the daytime maximum $O_3$ and minimum $NO_2$ concentrations tend to increase as the air temperature increases or the wind speed decreases. The daytime maximum $O_3$ concentration is more sensitive to the changes in air temperature and wind speed in the urban park than at the Gangnam AQMS.