• Journal of Veterinary Clinics
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• v.22 no.4
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• pp.342-347
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• 2005

This study was designed to assess the healing effects of ascorbic acid on full-thickness skin wound in dogs. Four $2.5\pm2.5cm$ full-thickness skin wounds were created bilaterally on the dorsolateral aspect in each of 5 dogs. The ten wounds were treated with ascorbic acid solution in the experimental group, and the ten wounds were treated with $0.9\%$ saline in the control group. The wound healing area was measured every other day for 3 weeks after the wounding. Statistical analysis was conducted with the paired t-test. On the $1^{st},\;3^{rd},\;5^{th},\; 7^{th},\;9^{th},\;11^{th},\;13^{th},\;15^{th},\;17^{th},\;19^{th},\;21^{st}days$, the wound healing rates were $12.6\pm9.6\%,\;9.5\pm9.8\%,\;18.9\pm9.0\%,\;39.2\pm5.4\%,\;62.2\pm4.6\%,\;86.9\pm1.9\%,\;92.9\pm1.8\%,\;96.6\pm1.6\%,\;99.1\pm0.5\%,\;99.8\pm0.2\%,\;99.9\pm0.1\%$ in the experimental group, and $9.1\pm6.0\%,\;9.2\pm6.0\%,\;12.2\pm5.0\%,\;41.3 \pm6.3\%,\;54.2\pm9.2\%,\;81.0\pm2.6\%,\;85.7\pm2.8\%,\;92.3\pm1.5\%,\;96.1\pm0.7\%,\;98.0\pm0.8\%,\;99.5\pm0.2\%$ in the control group On the $15^{th}$ day, the wound closed above $99\%$ in 2 dogs of the experimental group. On the $17^{th}$ day, the wound closed above $99\%$ in 3 dogs of the experimental group. On the $19^{th}$ day, the wound closed above $99\%$ in 5 dogs of the experimental group, and 2 dogs of the control group. On the $21^{st}$ day, the wound closed above $99\%$ in 5 dogs of the experimental group, and 4 dogs of the control group. The wound healing rate of the experimental group was $2\~4$ days faster than that of the control group. The tensile strength was $4,169\pm1,107g/cm^2$ in the experimental group, and $2,438\pm637g/cm^2$ in the countrol group on the$21^{st}$ day after wounding. Tensile strength was significantly higher in the experimental group than in the control group (p<0.05). The histopathological findings of the experimental group were similar to those of the control group on the $1^{st},\;3^{rd}\;and\;5^{th}$days. Inflammation and revascularization of the experimental group were similar to those of the control group on the $9^{th},\;13^{th}\;and\;21^{st}$days. The formation of collagen and reepithelialization were more developed the experimental group than in the control group on the $9^{th},\;13^{th}\;and\;21^{st}$days. Significantly higher wound healing rate, tensile strength and better histopathological findings were observed in the experimental group than in the control group. These results suggest that the topical application of ascorbic acid on full-thickness skin wounds can promote wound healing process.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.5
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• pp.303-309
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• 2008

The physico-chemical properties of the rainfall interception culture (85 sites) and the open field culture soils (85 sites) in the area of Gochang-gun, Jeollabuk-do were surveyed. Soil textural distribution of the rainfall interception culture and the open field culture soils was 74% and 64% for silt loam, 16% and 35% for loam, and 10% and 1% for clay, respectively. The percentage of aggregate rates was higher in the open field culture soils (60.06%) than rainfall interception culture soils (55.84%). Electrical conductivity, exchangeable cations, and anions in the rainfall interception culture soils were higher than those in open field soils. Specially, accumulated amount of anion in rainfall interception culture soils was remarkably higher 2~3 times than open field culture soils. The results from the analyses of rainfall interception culture soils suggested that the most critical problem is the salts accumulation caused by over-fertilization of chemical fertilizer and compost. Therefore, application rates of chemical fertilizer and compost should be controlled in order to conservation of soil and water for sustainable agriculture.

• Tuberculosis and Respiratory Diseases
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• v.66 no.2
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• pp.110-115
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• 2009

Background: A forceps-biopsy is performed to acquire tissue from patients with an endobronchial carcinoma using a flexible bronchoscope. Recently, a cryo-biopsy has also been used to acquire tissue samples. Cryo-biopsy is the diagnostic application of extreme cold for the local destruction of abnormal living tissue. This technique is safe, with no radiation danger, no risk of electrical accidents, and a little risk of bleeding. This study compared a forceps-biopsy with a cryo-biopsy using a flexible bronchoscope, and examined the chemosensitivity and level of VEGF (vascular endothelial growth factor) in the specimens obtained from the cryo-biopsy. Methods: We present a prospective study of 30 consecutive patients who underwent a forceps-biopsy between January 2007 and October 2007 with a mean age of 62.1 years and a male:female ratio of 5 : 1. A flexible bronchoscope was inserted to the area of the abnormal lesions, and a cryo-probe was then applied through the working channel of the flexible bronchoscope. A temperature of approximately -h80 was delivered to the tumor site for 8 seconds. The cryo-biopsy was performed after destroying the tumor mass. Results: The mean size of the tissue from the forceps-biopsy and cryo-biopsy were 2.0${\pm}$1.2 mm and 6.0${\pm}$3.0 mm. A chemosensitivity test was performed on 5 specimens obtained using cryo-biopsy and the level of VEGF was examined in 2 specimens obtained from a cryo-biopsy. There were no side effects in either group. Conclusion: Cryo-biopsy using a flexible bronchoscope is a safe and effective technique for acquiring tissue samples.

• Journal of the Korean Institute of Gas
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• v.23 no.6
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• pp.90-96
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• 2019

Natural gas has been regarded as one of major alternative fuels, because of the increment of mining shale gas and supplying PNG(Pipeline Natural Gas) from Russia. Thus, it needs to broaden the usage of natural gas as the increasing its supplement. In this situation, application of natural gas on the transport area is a good suggestion to reduce exhaust emissions such as CO₂(carbon dioxides) and soot from vehicles. For this reason, natural gas can be applied to SI(spark ignition) engines due to its anti-knocking and low auto-ignitibility characteristics. Recently, since turbocharged SI engine has been widely used, it needs to apply natural gas on the turbocharged SI engine. However, there is a major challenge for using natural gas on turbocharged SI engine, because it is hard to make natural gas direct injection in the cylinder, while gasoline is possible. As a result, there is a loss of fresh air when natural gas is injected by MPI (multi-point injection) method under the same intake pressure with gasoline-fueled condition. It brings the power reduction. Therefore, in this research, intake pressure was increased by controling the turbocharger system under natural gas-fueled condition to improve power output. The goal of improved power is the same level with that of gasoline-fueled condition under the maximum torque condition of each engine speed. As a result, the maximum power levels, which are the same with those of gasoline-fueled conditions, with improved brake thermal efficiency could be achieved for each engine speed (from 2,000 to 6,000 rpm) by increasing intake pressure 5-27 % compared to those of gasoline-fueled conditions.

• The Korean Journal of Air & Space Law and Policy
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• no.spc
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• pp.35-58
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• 2007

Nuclear Power Sources(NPS) have been used since 1961 for the purpose of generating energy for space objects and have since then been recognized as particularly suited essential to some space operations. In January 1978 a malfuctioning Soviet nuclear powered satellite, Cosmos 954, re-entered the earth's atmosphere and disintegrated, scattering radioactive debris over a wide area of the Canadian Northwest Territory. This incident provided some reasons to international legal scholars to make some principles to regulate using NPS in outer space. In 1992 General Assembly adopted "Principles Relevant to the Use of Nuclear Power Sources in Outer Space". These NPS Principles set out certain legal and regulatory requirements on the use of nuclear and radioactive power sources for non-propulsive purposes. Although these principles, called 'soft laws', are not legal norms, they have much enfluences on state practices such as 1983 DBS Principles(Principles Governing the Use by States of Artificial Earth Satellites for International Direct Television Broadcasting), 1986 RS Principles(Principles Relating to Remote Sensing of the Earth from Space) and 1996 Declaration on International Cooperation in the Exploration and Use of Outer Space for the Benefit and in the Interests of all States, Taking into Particular Account the Needs of Developing Countries. As far as 1963 Declaration of Legal Principles Governing the Activities of States in the Exploration and Use of Outer Space is concerned the main points such as free use of outer space, non-appropriation of celestial bodies, application of international law to outer space etc. have become customary international law binding all states. NPS Principles might have similar characters according to states' willingness to respect them.

• 대한공업교육학회지
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• v.36 no.1
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• pp.149-166
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• 2011

The purpose of this study was to develop a creative problem-solving competition program in order to provide an opportunity for junior high schoolers to solve problems on the basis of technological hands-on activities by deploying their creative problem-solving skills and to foster their cooperative and challenging spirits by tackling the given problems in group. Relevant literature and competition programs were analyzed to develop a junior high school competition program for creative problem solving on the basis of technological hands-on activities. This study was implemented in three stages: preparing, developing and applying. In the preparation stage, the content structure of technology and the fields of corresponding hands-on activities were investigated, and creativity theories were analyzed. Besides, domestic and foreign creativity-related competition programs were checked. In the development stage, an overview of the nature, object, question making and evaluation of a competition program for creative problem solving on the basis of technological hands-on activities was presented, and a program was developed, which consisted of three stages: planning, operating and evaluating. In the application stage, every student in a selected junior high school participated in the competition program. The findings of the study were as follows: First, the competition program developed in this study intended to offer a chance for every junior high schooler to solve problems on the basis of technological hands-on activities to display their creative problem-solving skills. Second, the program was designed to include planning, operating and evaluation stages, after the nature and object of the competition program and in which way question making and evaluation should be fulfilled were determined. Third, the competition program dealt with five areas according to the content structure of technology: manufacturing technology, construction technology, transportation technology, communication technology and biotechnology. And questions for each area and student worksheets were developed. Fourth, the program was utilized in a junior high school to give an example.

• Journal of Korean Society of Forest Science
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• v.104 no.3
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• pp.411-420
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• 2015

This study examined methods for stand density control by using shape ratio (tree height/DBH) and its application for effective management of Pinus thunbergii coastal disaster prevention forests. We analyzed the present conditions (height, DBH, and density) of P. thunbergii coastal disaster prevention forests at 123 study sites on Jeju Island and west, south, and east coasts of South Korea and compared them with results from previous studies. The average shape ratio for P. thunbergii showed positive correlations with stand density and was significantly higher on the west coast (66.32) than on the south (49.57) and east (48.19) coasts and Jeju Island (48.29). Stands with shape ratio higher than 70 accounted for 50% of the total study sites on the west coast, indicating a decrease in their disaster prevention function compared to that of other previous studies. The stand density in most coastal areas, except the east coast, was significantly higher than the standards recommended by the Korea Forest Service and the Forestry and Forest Products Research Institute of Japan, indicating the need for stand density control. According to the growth estimation equation for P. thunbergii in the coastal area of South Korea, density control is required for young stands less than 14 years old, which show drastic increase in the shape ratio, to conserve their disaster prevention function. Particularly, the first thinning of P. thunbergii forests should be implemented before the stand age of 8 years that a shape ratio exceeds 70. For disaster-prone young stands (${\leq}20cm$ DBH) of P. thunbergii, the stand density was higher in the standard of Japan considering shape ratio than in that of Korea aiming timber production. Hence, the standard guidelines employed in Japan, which assign higher importance to disaster prevention function based on field surveys, can be applied effectively for controlling the stand density of P. thunbergii coastal forests in South Korea, to improve their disaster prevention function.

• Journal of Korean Society of Forest Science
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• v.17 no.1
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• pp.35-42
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• 1973

Deciduous trees grown naturally in the forest of Korea usually have an irregular Lee-form and their utility has been decreased. In Korea, most of the deciduous stands are distributed in the hinterland. A shortage of the total growing stock made utilization of them necessary in this country even though some difficulties to be cutted and transported are accompanied. Therefore, this study was conducted to select the suitable sampling method for surveying them. The results investigated are as follows. 1. Three locations being 10 hectares in each location for the plots were chosen and surveyed with six $20m{\times}50m$ rectangular sample plots by four types of sampling method below. And the result is shown in Table 1. A. Random sampling by grids B. Random sampling by co-ordinates C. Systematic line plot. D. Sub-sampling 2. One hundred and fifty hectares from all plots were sectioned through the application of aerial photography scaled of 1 : 15,000. The author divided forest types according to diameter class and crown density with mirror stereoscope. The forest types were divided into three classes. Seven sample plots from the area of 150 hectars are systematically arranged and the results investigated on the circular sample point of 0.1 hectare are shown in Table 4. 3. There were no significant differences between results by sampling method and by diameter measurement method (population mean) as shown in Table 3. 4. Random sampling by grid and systematic line plot are better than others. 5. There are more over-estimated values when the circular sample point is used than where the rectangular sample point. 6. As forest stands are irregular, smaller number of sample points will make many errors.

• Journal of Korean Society of Forest Science
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• v.83 no.3
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• pp.311-321
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• 1994

Experiments were conducted to evaluate the efficacy of ground and foliar sprinkling of natural water for control of the pine needle gall midge, Thecodiplosis japonensis, by disturbing the reproductive behavior of adults such as copulation and oviposition. Diurnal ground spray for whole area application and foliar spray for single tree treatment were tested at day time during the period of adult emergence. The results obtained are as follows : 1. The population density of overwintering larvae in soil was not affected by the water spray during the adult emergence period. 2. Spraying the water showed no effect on the whole period and number of adult emergence, but retarded early emergence and facilitated Late emergence. The difference in the emerging time by 50% emergence day was approximately 7 days. 3. Ground spray was significantly different from control in gall formation rates but was not sufficient for effective control. As a single-tree treatment, the foliar spray was found to be highly effective for control of the pine needle gall midge, Average gall formation of spray plots and untreated ones were 2.6% and 38%, respectively ; control value exceeded 90%. 4. Ground spray of water was not effective in reducing larvae in gall of needle. Foliar spray, however, reduced 45% of larval numbers. 5. Foliar spray accelerated shoot growth by 15%-18%. 6. Foliar spray was highly effective for the control of sucking insects, such as mites and aphids on pine trees.

• The korean journal of orthodontics
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• v.33 no.4 s.99
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• pp.279-291
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• 2003

Electric current is a highly probable way as a clinical tool for tooth movement. The purposes of this study were to determine the usefulness of exogenous electric currents in accelerating orthodontic tooth movement and to investigate the effects of electric-orthodontic treatment on the remodeling of the periodontal tissue histologically The study was performed with six male cats weighing around 3kg. The electric device wich is providing the direct electric current of $20{\mu}A$ was inserted to the removable appliance. The right and left maxillary canines were assigned as control and experimental sides respectively. The control canine was Provided with orthodontic force (75gm) oかy and the experimental side was given the same amount of force and electricity. The lingual buttons were bonded to the maxillary canines and both sides of canines were retracted with NiTi coil spring. The electric device was adjusted to provide 20uh direct current to the experimental canines S hours a day The amount of the canine movement was measured with electronic caliper every week. After 4 weeks of tooth movement, the animals were sacrificed and the histologic study was performed. The results of this study were as follows. 1. The application of a direct current to the experimental tooth significantly increased the final amount of orthodontic tooth movement. The amount of tooth movement after 28-day was 37% more in the experimental side. 2. The electrically stimulated tooth showed histologic evidence of significant increases in the amount of bones and matrix deposition in the area of tension. 3. In the compression side, the electric-orthodontic treatment stimulated bone resorption more extensively in the experimental canines. 4. After 28 days of electricity exposure and orthodontic force, the experimental side demonstrated significantly more osteoblasts, osteoclasts, capillaries and osteoid tissues, reflectinr an increase in the local tissue's cellular activity. 5. Intermittent electrical stimulation (five hours a day) had effects to enhance orthodontic tooth movement and tissue remodeling. These results suggested that the low-intensity exogenous electric current by the miniature electric device might accelerate orthodontic tooth movement and bone remodeling in vivo and have the possibility to reduce the orthodontic treatment duration.