• Journal of Korean Society of Forest Science
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• v.107 no.4
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• pp.336-343
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• 2018

This study was carried out to provide the technology of silvicultural practices and management for regeneration by sprouts in the oak forests distributed on the slope. A total of 1,451 stumps were examined for the following factors relative to the occurrence and growth of the sprouts: stump height & diameter; location & quantity and root collar diameter & height of arisen sprouts. The amount of sprouts deceased or increased as the stump diameter increased. However, it tended to increase with stump height. The difference in the stump height between direction of the upwards (DUS) and downward slopes (DDS) was occurred, because oak trees were felled lower based on direction of the upward for convenience of regeneration works on the slope. The number of sprouts was higher relatively in the stumps of DDS. The rate of arisen side and root sprouts was higher in the stumps of DDS and DUS, respectively. The stump height difference was found to affect the arisen part of sprouts. As a result of comparing the sprouts growth according to the arisen part, there was no difference in the stump of DUS, but the growth of side sprouts in the stump of DDS was higher than that of the root. In order to improve the quality of oak sprouts considering the distribution characteristics of the oak forests in South Korea, it is necessary to apply the silvicultural technique, making the cutting surface parallel with the slope to reduce the stump height difference, to suppress arising side sprouts.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.67 no.2
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• pp.77-84
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• 2022

This study aimed to evaluate the growth, yield, and grain quality characteristics of rice varieties that were subjected to water stress during the tillering stage. We also sought to identify whether water stress could be indicated via the plants' response to chlorophyll fluorescence. In this study, we induced water stress by intentionally cutting off water for 30 days, starting 15 days after transplanting the rice varieties to a greenhouse. We analyzed nine rice varieties, including Ilpum, which is the most frequently cultivated variety in Gyeongsangbuk-do, South Korea. The control group was planted in a paddy field where irrigation was entirely dependent on rainfall. Our results revealed that the heading stage of the nine studied varieties occurred approximately ten days earlier in the rain shelter than in the field. Moreover, the rice yield, head rice rate, and palatability score decreased by 18.6%, 17.1%, and 8.3%, respectively, while protein content increased by 20.2% compared with the control group. The Saenuri and Haimi varieties showed the lowest reduction in yield under the water stress conditions, while the Daebo and Samkwang varieties showed the highest reduction in yield. The chlorophyll fluorescence response after re-irrigation was measured between July 30^th and August 17^th. The ratio of variable fluorescence to maximum chlorophyll fluorescence (F_V/F_M) values failed to recover to their baseline values, resulting in either no change or a reduction in fluorescent response, even after re-irrigation of Daebo and Samkwang varieties. These results can be utilized as empirical data for drought-affected farms to select resistant varieties that can respond to spring drought in the southern plains of Gyeongsangbuk-do.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.5
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• pp.799-810
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• 2022

Welding work is a production work method widely used throughout the industry, and various types of welding technologies exist. In addition, many methods are being studied to automate these welding operations using robots, but in the ship manufacturing field, welding such as painting, cutting, and grinding is also the most common operation, but the manual operation ratio is higher than in other industries. Such a high manual labor ratio in the field of ship manufacturing not only causes quality problems and production delays according to the skill of workers, but also causes problems in the supply and demand of manpower. Therefore, this paper analyzed the reason why the automation rate is low in welding work at ship manufacturing sites compared to other industries, and analyzed the production process and field environment for small and medium-sized ship manufacturing companies that repeatedly manufactured with a small quantity production method. Based on the analysis results, it is intended to propose a robot system that can easily move between workplaces and secure uniform welding quality and productivity by collaborating simple welding tasks with humans. Finally, the simulation environment is constructed and analyzed to secure the suitability of robot system application to current production site environment, work process, and productivity, rather than to develop and apply the proposed robot system. Through such pre-simulation and robot system suitability analysis, it is expected to reduce trial and error that may occur in actual field installation and operation, and to improve the possibility of robot application and positive perception of robot system at ship manufacturing sites.

• Journal of the Korean Wood Science and Technology
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• v.32 no.2
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• pp.90-95
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• 2004

Pitch pine (Pinus rigida) has been planted in Korean forests for several decades, primarily for erosion control and use as a fuel supply. To enhance its value, and especially potential use as lamina for structural glued laminated timber (glulam), log quality and lumber yield of pitch pine were evaluated in this study. Trees from pure pitch pine stands with an average diameter at breast height of 32 cm were felled and bucked into 3.6m long 15 cm minimum butt-end diameter logs. Over 80% of the logs were classified to No.2 or No.3 visual grade group. Upon sawing total lumber yield was 55.2%, 39.9% for structural glulam lamina, 7.2% for louver, and 8.1% for miscellaneous use. The final lumber yield for manufacturing structural glulam, after cross-cutting to eliminate knots and finger jointing, was only 15.3%. To enhance this manufacturing yield requires that the rate of knot-included lumber used as lamina be raised. However arrangement of the knot-included lamina, whose mechanical properties need to be accurately evaluated, must be optimized to minimize any reduction to the structural glulam strength. The log quality and lumber yield of pitch pine evaluated in this study are expected to facilitate proper planning for wood product manufacture in the Korean lumbering and glulam industrial field, which has not previously dealt with this species.

• Clean Technology
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• v.28 no.4
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• pp.323-330
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• 2022

Microfluidic paper-based analytical devices (μPADs) have recently been in the spotlight for their applicability in point-of-care diagnostics and environmental material detection. This study presents a double-sided printing method for fabricating 3D-μPADs, providing simple and cost effective metal ion detection. The design of the 3D-μPAD was made into an acryl stamp by laser cutting and then coating it with a thin layer of PDMS using the spin-coating method. This fabricated stamp was used to form the 3D structure of the hydrophobic barrier through a double-sided contact printing method. The fabrication of the 3D hydrophobic barrier within a single sheet was optimized by controlling the spin-coating rate, reagent ratio and contacting time. The optimal conditions were found by analyzing the area change of the PDMS hydrophobic barrier and hydrophilic channel using ink with chromatography paper. Using the fabricated 3D-μPAD under optimized conditions, Ni²⁺, Cu²⁺, Hg²⁺, and pH were detected at different concentrations and displayed with color intensity in grayscale for quantitative analysis using ImageJ. This study demonstrated that a 3D-μPAD biosensor can be applied to detect metal ions without special analysis equipment. This 3D-μPAD provides a highly portable and rapid on-site monitoring platform for detecting multiple heavy metal ions with extremely high repeatability, which is useful for resource-limited areas and developing countries.

• Journal of Animal Science and Technology
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• v.45 no.4
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• pp.577-584
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• 2003

Three dietary treatments were compared over two years to determine the effects of dietary protein levels and feeding patterns on velvet production in red deer (Cervus elaphus). The LL group received a 13% protein diet whereas the HH group received a 19% protein diet. The LH group switched from the low to high protein diet at the time of antler casting. Significant relationships were found between velvet production and the girth and length of main beam (p<0.01), daily growth rate of velvet (p<0.01), body weight at cutting time (p<0.05 in 1998 and p<0.01 in 1999), date of casting (p<0.01), and body weight and velvet production of the previous year (p<0.05 in 1998 and p<0.01 in 1999). Different levels of protein in diets in this study did not show statistically significant different effects in general. The girth of velvet, summed for top, middle and bottom of the main beam, tended to be thickest in HH for two years and thinnest in LL for 1998 and in LH for 1999. The main beam tended to be longest in HH at 46.3cm in 1998 and 45.2cm in 1999 and shortest in LH at 39.9cm in 1998 and 41.5cm in 1999. Velvet fresh weight tended to be highest in HH at 2,600$\pm$1,000g in 1998 and 3,038$\pm$867g in 1999 and lowest in LH at 2,287$\pm$826g in 1998 and 2,739$\pm$1,079g in 1999. Daily growth rate of velvet antler tended to be greatest in HH (43$\pm$16g/day in 1998 and 51$\pm$14g/day in 1999) and least in LH (38$\pm$15g/day in 1998 and 45$\pm$18g/day in 1999).

• Magazine of the Korean Society of Agricultural Engineers
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• v.13 no.2
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• pp.2262-2275
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• 1971

Fourteenes rervoirs maintained by the local land improvement associations in the province of Chullabuk-Do and 20 reservoir maintained by thos in the province of Chullanam-Do, were surveyed in connection with a correction between storage capacity and sediment deposit. In addition to this survey, 3,347 of small reservoir, that lie scattered around in the above-mentioned two provinces were investigated by using existing two provinces were investigated by using existing records pertaining to storage capacity in the office of City and country, respectively. According to this investigation the following comclusions are derived. 1. A sediment deposition rate is high, being about $10.63m^3/ha$ of drainage area, and resulting in the average decreasc of storage capaity by 27.5%. This high rate of deposition coule be mainly attributed to the serve denudation of forests due to disorderly cuttings of trees. Easpecially, in small reservoir, an original average design storage depth of 197mm in irrigation water depth is decreased to about 140mm. 2. An average unit storage depth of 325.6mm as the time of initial construction is decreased to 226mm at present. This phenomena causes a greater shortage irrigation water, since it was assumed that original storage quantity was already in short. 3. Generally speaking, seepage rates through dam abutment intakepipe, etc, are high due to insufficient maintenance and management of reservoir. 4. It is recommended that sediment deposit should be dredged when a reservoir is dry in drought. 5. Farmers usually waste excessive irrigation water. 6. Water saving methods should be practiced by applying only necessary water for growing stage of rice. 7. In are as where water defficiency for irrigation is severe, a soil moisture content should be kept at about 70% by applying water once in several days. 8. Tube wells should be provided so as to exploit ground water and subsurface current below stream bed as much as possible. 9. If an intake weir was constructed, a water collection well should be built for the use in drought. 10. Water conservation should be forced by converting devastated forests contained in the drainage area of reservoir to protected forests so as to take priority of yrefor estation, gully control, the prohibition of disorderly cutting of trees, etc. 11. Collective rice nurseries should be adopted, and it should be recommended that irrigation water for rice nurseries is supplied by farmer themselves. 12. Sediment desposit in reservoir should be thoroughly dreged so as to secure a original design storage capacity. 13. The structure of overflow weir should be automatic so as to freely control flood level and not to increase dam height.

• Current Research on Agriculture and Life Sciences
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• v.9
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• pp.147-155
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• 1991

Effects of harvest date, number of the leaves remained on stump after flower cutting, duration of cold treatment on the growth and flowering of L. elegans 'Connecticut King' bulb were tested. Shoot emerging rate increased over 90% by delayed cold treatment, late harvesting time and more leaves remained. Flowering rate increased over 90% when conducted cold treatment of 90 days to the premature bulb at flowering date, the bulb matured for 50 days with 10 leaves and the bulb matured for over 30 days with 20 leaves, and when conducted cold treatment of 50 days to the bulb matured for over 30 days with all leaves. Delayed cold treatment duration shortened days needed to shoot emergence and flowering. Especially days to flower of the premature bulb at flowering date were the shortest of all treatments, and can be flowered within 100 days after planting. In generally, plant height, number of flowers per plant and stem diameter generally increased by longer bulb maturing period after flower cuting, and the premature bulb harvested at flowering date showed poor growing and flowering responses. But, if used the larger size bulb, it is believed that the prematured bulb can be forced to flower normally in current year without bulb maturing period.

• Korean Journal of Weed Science
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• v.16 no.2
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• pp.114-121
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• 1996

This study was conducted to investigate seed germination, seedling growth, and responses to herbicides of Bidens tripartita L. When the field-collected seeds were stored under a dry-room temperature, dry-low temperature, wet-low temperature, or dry-high temperature condition, no seeds were germinated in a growth chamber with 14 hr photoperiod up to 35 days after the storage. Exceptionally, however, some seeds stored under a wet-room temperature condition were germinated after 25 days of the storage. This might be due to the fact that the seed coats were damaged by fungi which developed during the storage. Seeds stored under a wet-low temperature condition (stratification) began to be germinated after 3 months of the storage and the germination rate increased with a prolonged stratification. Almost all seeds were germinated after 9 months of the stratification. These results suggest that the dormancy of B. tripartita L. seeds relate to the seed coat and thus several attempts were made to induce seed germination through damaging or weakening the seed coat. Freezing($-20^{\circ}C$), drying($100^{\circ}C$), or swelling($40^{\circ}C$) of the seeds was not effective to induce the germination. Treatments of concentrated sulfuric acid, $KNO_3$, or gibberellin to the seeds had no effect on inducing the germination. However, ethrel had a stimulatory effect on the germination of the seeds with an optimum concentration of 250ppm. A seed cutting was also effective to induce the germination, but seedlings from the seeds had cutted cotyledons. Germination of the stratified seeds varied with the temperature condition to which they were subjected, but not with light. The germination rate was the highest at 35 - $40^{\circ}C$. Although the seeds were not able to germinate under a submerged condition, seedlings after 2-leaf-stage exhibited better growth under a submerged or a subirrigated condition than under an upland condition. Among the herbicides tested, pyrazosulfuton-ethyl, linuron, and bentazone were found to be effective for controlling B. tripartita L., having more herbicidal effect with an earlier application.

• Journal of Chest Surgery
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• v.41 no.6
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• pp.710-717
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• 2008

Background: Atrial fibrillation is associated with several complications such as cerebro-vascular accidents and peripheral arterial embolism. Most of the patients who have this arrhythmia chronically feel their heart beating and so they are frightened; therefore, the quality of a patient's life is decreased. The purpose of this article is to determine the long term results of a modified Maze procedure and the factors that influence the success of the procedure. Material and Method: This study enrolled 88 patients who underwent the modified Maze with using cryoablation between June, 2001 and February, 2007. The 88 consecutive patients were divided into two groups ac cording to how the pulmonary veins were isolated, that is, with or without cryoablation. There were 58 patients who were isolated by cutting and sewing in the right pulmonary veins and by cyroablation in the left pulmonary veins in group 1 (group 1, n=58), and 30 patients who underwent isolation by cryoablation in the right & left pulmonary veins were placed in group 2 (group 2, n=30). The ECG was checked at discharge to determine the sinus conversion rate and we followed up the patients to determine whether or not the patients maintained sinus rhythm. We also checked the ECG at the last visit to determine the patients' heart rhythm. Result: The mean follow up time was $44.3{\pm}19.2$ months. At discharge, 72.4% of the patients in group 1 were in proper sinus rhythm and 66.7% of the patients in group 2 were in proper sinus rhythm. At the last follow up, 81% of the patients in group 1 were in normal sinus rhythm and 60% of the patients in group 2 were in normal sinus rhythm. When we analyzed the data via the Kaplan-Meier method, 86.5% of the patients were free from atrial fibrillation (% free from AF) at 1 year, 80% of the patients were free from atrial fibrillation at 5 year in group 1 and 70% of the patients were free from atrial fibrillation at 1 year and 51 % of the patients in group 2 were free from atrial fibrillation at 5 year. Conclusion: The modified Maze technique using cryoablation was a simple and effective procedure. But the success rate of the Maze technique using cryoblation is lower than that of the standard Maze III. The method using cryoablation shorten the operation time, but we must conduct more studies to get a better result of the modified Maze technique with using cryoablation.