• Geomechanics and Engineering
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• v.36 no.5
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• pp.427-440
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• 2024

This study concentrates on the 301 comprehensive caving working face, notable for its considerable mining height. The roof model is established by integrating prior geological data and the latest borehole rock stratum's physical and mechanical parameters. This comprehensive approach enables the determination of lithology, thickness, and mechanical properties of the roof within 50 m of the primary mining coal seam. Utilizing the transfer rock beam theory and incorporating mining pressure monitoring data, the study delves into the geometric parameters of the direct roof, basic roof movement, and roof pressure during the initial mining process of the 301 comprehensive caving working face. The direct roof of the mining working face is stratified into upper and lower sections. The lower direct roof consists of 6.0 m thick coarse sandstone, while the upper direct roof comprises 9.2 m coarse sandstone, 2.6 m sandy mudstone, and 2.8 m medium sandstone. The basic roof stratum, totaling 22.1 m in thickness, includes layers such as silty sand, medium sandstone, sandy mudstone, and coal. The first pressure step of the basic roof is 61.6 m, with theoretical research indicating a maximum roof pressure of 1.62 MPa during periodic pressure. Extensive simulations and analyses of roof subsidence and advanced abutment pressure under varying working face lengths. Optimal roof control effect is observed when the mining face length falls within the range of 140 m-155 m. This study holds significance as it optimizes the working face length in thick coal seams, enhancing safety and efficiency in coal mining operations.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.6
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• pp.113-120
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• 2007

For the cases of constructing reinforced earth and gabion walls on the soft ground, an appropriate replacement area of soft ground required to maintain the stability of walls was investigated by FEM analyses. Incremental analyses were performed in FEM, in which construction sequences including consolidation of soft soil layer were simulated. As a first step to suggest the appropriate replacement area, a series of analyses for cases varying the replacement depth were conducted to examine the behaviors of wall and adjacent ground according to the construction sequence. The analysis results were, then, evaluated with the proper limiting values of displacements of wall, settlements and shear strains of ground to guarantee the stability of walls, which were specified based on the literature review. Consequently, the typical construction drawings could be suggested, in which appropriate replacement areas for varying wall heights for the ground condition investigated in this study were represented in terms of the ratio of replacement depth to the height of wall.

• Journal of the Korean Orthopaedic Association
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• v.56 no.3
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• pp.224-233
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• 2021

Purpose: The purpose of this study was to retrospectively evaluate the effect of 'Blocking Kirschner Wire (K-Wire) Technique', which has been developed to reduce protrusion of the lateral wall, in maintaining the level of reduction through clinical and radiological outcomes. Materials and Methods: Twenty-two patients with displaced intra-articular calcaneal fractures who used the blocking K-wire to maintain reduction (group A) and 44 patients that did not use blocking K-wire and were paired in 1:2 ratio with those Group A patients (group B), between January 2015 and December 2017 were enrolled in the study. All surgical procedures were performed via the extended sinus tarsi approach, and internal fixation using cannulated screws, Steinmann pins and K-wires was performed. American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot scale and postoperative recovery of exercise ability were compared for postoperative clinical outcomes. The radiological results were compared the Böhler angle, Gissane angle, calcaneal height and width, step off of posterior calcaneal joint, and the degree of protrusion of the lateral wall. Moreover, postoperative complications in both groups were compared. Results: There were no significant differences in the clinical outcomes of the two groups (p=0.924, p=0.961). The amount of Böhler angle, Gissane angle, calcaneal height and width, and step off of posterior calcaneal joint from the radiological results was not significantly different between the two groups (p=0.170, p=0.441, p=0.230, p=0.266, and p=0.400). However, the degree of protrusion of the lateral wall was 1.78 mm and 4.95 mm in group A and group B, respectively, and the difference between the two groups was significant (p=0.017). Although sural nerve entrapment and painful exostosis were more frequent in group B, they were occurred in a non-significant manner (p=0.293, p=0.655). Conclusion: Most of the clinical and radiological results as well as the complications were not significantly different between the two groups. However, the degree of protrusion of the calcaneus lateral wall in group A was promising. The 'Blocking K-Wires Technique' established by the authors may be an effective surgical option for maintaining the reduction of the lateral wall protrusion in displaced intraarticular calcaneal fractures.

• Research in Community and Public Health Nursing
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• v.9 no.2
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• pp.502-517
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• 1998

This research intends to survey family environment, health behavior and health status of the students in urban-rural elementary schools and analyze those factors comparatively, and use the result as basic material for school health teacher to teach health education in connection with family and regional areas. It also intends to improve a pupil's self-abilitiy in health care. The subjects involve 2,774 students of urban elementary schools and 583 student in rural ones, who were selected by means of a multi -stage probability sampling. Using the questionnaire and school documents, we collected data on family environment, health behavior and health status for 19 days. Feb. 2nd 1998 through Feb. 20th 1998. The R -form of Family Environment Scale (Moos, 1974) was used in the analysis of family environment(Cronbach's Alpha =0.80). Questionnaires of Health Behavior in School-aged children used by the WHO in Europe(Aaro et al., 1986) and the ones developed by the Health Promotion Committee of the Western Pacific(WHO, 1995)(adapted by long Young-suk and Moon Young-hee(1996)) were used in the analysis of health behavior, as well documents on absences due to sickness, school health room-visits, levels of physical strength, height, weight and degree of obesity were used to determine health status. In next step, We used them with an $X^2$-test, t-test, Odds Ratio, and a 95% Confidence Interval. 1. In two dimensions of three, family-relationship (t=3.41, p=0.001) and system -maintenances(t= 2.41, p=0.0l6) the mean score of urban children were significantly higher than those of rural ones. In the personal development dimension however, there was little significant difference. Assorting family environment into 10 sub-fields and analyzing them, we recognized that urban children were superior to rural children in the sub-fields of expressiveness (t =3.47, p=0.001), conflict (t=0.48, p=0.001), active-recreational orientation (t = 1.97, p=0.049) and organization (t=4.33, p=0.000). 2. Referring to the Odds Ratios of urban-rural children's health behaviors, urban children set up more desirable behavior than rural children wear ing safety belts (Odds Ratio =0.32, p=0.000), washing hands after meals(Odds Ratio = 0.43, p= 0.000), washing hands after excreting (Odds Ratio = 0.39, p=O.OOO), washing hands after coming - home ( Odds Ratio = 0.75, p = 0.003), brushing teeth before sleeping(Odds Ratio =0.45, p=0.000), brushing teeth more than once a day (Odds Ratio =0.73, p=0.0l2), drinking boiled water (Odds Ratio = 0.49, p=0.000), collecting garbage at home(Odds Ratio=0.31, p=0.000) and in the school(Odds Ratio =0. 67, p=0.000). All these led to significant differences. As to taking milk(Odds Ratio = 1.50, p=0.000), taking care of eyesight(Odds Ratio=1.41, p=0.001) and getting physical exercise in(Odds Ratio = 1.33, p=0.0l9) and outside the school(Odds Ratio = 1.32, p=0.005), rural children had more desirable behavior which also revealed a significant difference. There was little significant difference in smoking, but the smoking rate of rural children(5.5%) was larger than that of urban children(3.9%). 3. Health status was analyzed in terms of absences, school health room-visits, levels of physical strength, and the degree of obesity, height and weight. Considering Odds Ratios of the health status of urban-rural children, the health status of rural children was significantly better than that of the urban ones in the level of physical strength(t=1.51, p=0.000) and the degree of obesity(t=1.84, p=0.000). The mean height of urban children ($150.4{\pm}7.5cm$) is taller than that of their counterparts($149.5{\pm}7.9$), which revealed a significant difference (t =2.47, p=0.0l4). The mean weight of urban children($42.9{\pm}8.6kg$) is larger than that of their counterparts($41.8{\pm}9.0kg$), which was also a significant difference(t=2.81, p=0.005). Considering the results above, we can recognize that there are significant differences in family environment, health behavior, and health status in urban-rural children. These results also suggestion ideas for health education. What we would suggest for the health program of elementary schools is that school health teachers should play an active role in promoting the need and importance of health education, develop the appropriate programs which correspond to the regional characteristics, and incorporate them into schools to improve children's ability to manage their own health management.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.37 no.2
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• pp.106-116
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• 2001

A serious of studies on the fishing gear and system of the East Sea trawl fishery was carried out to improve the fishing efficiency and the working conditions. As the first step of these studies, the fishing gear and system of the traditional East Sea trawl were checked in order to solve the some problems, such as the poor sheering efficiency of net mouth, the inconvenient fishing system of the side trawl and etc. And then the fishing system was reorganized from the side trawl into the stern trawl by setting up the net drum system on the stern deck, and introduction of two types of new designed nets, one for mainly the midwater trawl and the other for the bottom trawl. The results of the field experiment on the modified system and nets can be summarized as follows : 1. the modified system was well worked and could save the man-labour by about 80%. 2. The sheering efficiency of the improved net, A type was improved to 20 m height and 30 m width in the net mouth, and that of B type net, to 10 m height and 33 m width, compared with 1.5 m height and 15 m width in the traditional net. 3. Catch efficiency of pink shrimp in A or B type net was better about 3 or 5 times than that of traditional net, and in B net, for herring and other bottom fishes is better about 2 times than that of the traditional net.

• Journal of the Korean earth science society
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• v.45 no.2
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• pp.136-146
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• 2024

This paper introduces the seismic facies classification and mapping of igneous bodies found in the sedimentary sequences of the Yellow Sea shelf area of Korea. In the research area, six extrusive and three intrusive types of igneous bodies were found in the Late Cretaceous, Eocene, Early Miocene, and Quaternary sedimentary sequences of the northeastern, southwestern and southeastern sags of the Gunsan Basin. Extrusive igneous bodies include the following six facies: (1) monogenetic volcano (E.mono) showing cone-shape external geometry with height less than 200 m, which may have originated from a single monogenetic eruption; (2) complex volcano (E.comp) marked by clustered monogenetic cones with height less than 500 m; (3) stratovolcano (E.strato) referring to internally stratified lofty volcanic edifices with height greater than 1 km and diameter more than 15 km; (4) fissure volcanics (E.fissure) marked by high-amplitude and discontinuous reflectors in association with normal faults that cut the acoustic basement; (5) maar-diatreme (E.maar) referring to gentle-sloped low-profile volcanic edifices with less than 2 km-wide vent-shape zones inside; and (6) hydrothermal vents (E.vent) marked by upright pipe-shape or funnel-shape structures disturbing sedimentary sequence with diameter less than 2 km. Intrusive igneous bodies include the following three facies: (1) dike and sill (I.dike/sill) showing variable horizontal, step-wise, or saucer-shaped intrusive geometries; (2) stock (I.stock) marked by pillar- or horn-shaped bodies with a kilometer-wide intrusion diameter; and (3) batholith and laccoliths (I.batho/lac) which refer to gigantic intrusive bodies that broadly deformed the overlying sedimentary sequence.

• Journal of Korean Society of Forest Science
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• v.45 no.1
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• pp.26-36
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• 1979

Through several trials that has done for making the fertilizing-counter plan on the soil improving species, some results have been got as follows; 1. In the non-phosphorus dressing plots soil improving species have very poor survial ratio and show us to be died step by step. It may be resons that root can not make the nodule in case of non-phosphorus dressing and so tree could not absorb the nitrogen nutrient fixed by the nodule. And root competition with the weedy speces for utilizing the nutrient and oxygen in the soil could be reasons when planting in the heavy weedy rooting site. 2. Triple super phosphate, Fused Mg Phosphate and Fused super phosphate have showed the remarkable effects on the growth of soil improving species within 3rd year after planting. But Koreaan tablet fertilizer(9-12-4) for forest purpose have reacted considerably lower effect in comparision with the above powder and grain type phosphorous fertilizer. 3. In case of tablet type fertilizer tree root will have very little phosphorus absorbing surface because phosphorus can be utilized only from the tablet surface and root can not penetrate into the tablet. This my be reson to show the poor dressing reaction of tablet fertilizer but tablet fertilizer has a possibility to be utilized during long years as a sympton in photo 6. So tablet fertilizer can have a recommendation to dress much fertilizer at p]anting year and then tree root can get much more chance for absorbing the phosphorus that could keep the high survival and for utilizing it during many years without after dressing. 4. The granurar and powder type phosphate can develop the dense root mat like photo 8 because of giving the large surface for absorbing the phosphorus and weedy root can approch to the nodule for taking the nitrogen element. So this type seems to present better effect than tablet type to control the soil movement, stem weight as 200g per meter(l meter long${\times}$0.1m width). When added the lime any effect could not be found and rather give the negative effect. So Lespedeza seed sowing and phosphorus dressing system seems us to be very reasonable method for covering the raw material of basket making, fodder and fuel wood supply. 7. Fused Mg phosphate and Fused super phosphate are good fertilizer to the soil improving species and dressing more than 30g per seedling can be recommendable amount. 5. In the unproductive and dry soil with phosphorus fertilizer Robinia pseudoacacia and Alnus firnui can grow more than 2.3m in height at 3rd year and Alnus inokumae have the rapid height growth that is more than 1.8m at 2nd year. Depending on the growth situation like the above example minirotated management has possibilities and rapid covering of erosed land can be done with the soil improving species and phosphorus fertilizer. 6. In the Lespedeza sowing plot with 40g Fused Mg phosphate dressing per meter in the eroded and unproductive forest soil Lespedeza have completely covered this poor land and produced the green.

• Journal of Community Nutrition
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• v.5 no.1
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• pp.29-36
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• 2003

This study investigated the correlation of the physical measurements and the basic physical fitness of 158 female students in the city of Seoul. The average age of the subjects was 22.0 ${\pm}$ 0.13 years old, the average height was 160.9 ${\pm}$ 0.7cm and the average weight was 53.4 ${\pm}$ 0.6kg. The mean BMI (Body Mass Index) was 20.7 ${\pm}$ 0.2kg/㎡. The average muscle mass was 36.5 ${\pm}$ 0.3 and the average body fat percentage was 28.0 ${\pm}$ 0.4%. The basic fitness levels of the subjects were measured based on the evaluation chart of the Korea Health and Science Research Institution (1994). The subjects were divided into 3 groups based on BMI(Group I : BMI < 20, Group II : 20 $\leq$ BMI < 25, Group III BMI $\geq$ 25) and the correlation between BMI and physical fitness was assessed. 1) The muscle strength of the subjects was measured by their grip strength, among other tests. Groups 1 and 2 were evaluated as “su” (level 1) and group 3 was “woo” (level 2). 2) Endurance 1 was tested by push-ups, and while groups 1 and 2 were evaluated as “su” (level 1), group 3 was “ga” (level 5). This result did not suggest any significant relevance among the subjects. 3) Endurance 2 was tested by sit-ups : groups 1 and 2 were evaluated as “mi” (level 3) and group 3 as “yang” (level 4). Group 2 and group 3 showed a significant difference. 4) Instant power was tested by standing high jumps, and although there was a significant difference between group 1 and group 3, all of the subjects were evaluated as “ga” (level 5). 5) Flexibility was measured by how far the subjects could bend forward. There was no significant relevance between the groups and they were all respectively evaluated as “woo” (level 2). 6) Agility was tested with side-steps and all the subjects showed poor agility as “yang” (level 4). 7) Heart and lung endurance was tested by the step test, calculating the maximum oxygen intake with the Physical Energy Index (PEI) and using the numbers according to the evaluation chart. Group 1 was evaluated as “mi” (level 3) and groups 2 and 3 were “woo” (level 2). From these results, we could see the group III (obese group) had a tendency of lower levels in all the variables related to body fitness They showed significantly lower endurance assessed with time for sit-ups and instant power by the standing high jumps. (J Community Nutrition 5(1) : 29∼36, 2003)

• Journal of Periodontal and Implant Science
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• v.40 no.1
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• pp.3-10
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• 2010

Purpose: Periodontal regenerative therapies for defects created by severe periodontitis are mainly focused on bone regeneration. Although cementum regeneration needs to be better understood, it is believed to play an important role in periodontal regeneration. The first step toward a full understanding of cementum regeneration is to compare repaired cementum to pristine cementum. This study, which used histological techniques, was designed to focus on cementum regeneration and to compare pristine cementum to repaired cementum after surgical procedures with 8 and 24 week healing periods in a canine model. Methods: Buccal and lingual mucoperiosteal flaps of 10 beagle dogs were surgically reflected to create critical-sized defects. Intrabony one-wall defects, of which dimension is 4 mm width and 5 mm depth, were made at the distal aspect of mandibular second premolars and the mesial aspect of mandibular fourth premolars in the right and left jaw quadrants. Animals were sacrificed after 8 and 24 weeks post-surgery for histological specimen preparation and histometric analysis. Results: The repaired cementum was composed mostly of acellular cementum and cellular mixed fiber cementum and was thicker in the apical area than in the coronal area. The acellular cementum of the supracrestal area appeared to be amorphous. The newly formed cellular cementum was partially detached from the underlying circumpulpal dentin, which implied a weak attachment between new cementum and dentin, and this split was observed to a lesser extent in the 24 week group than in the 8 week group. The vertical height of the repaired cementum was greater in the 24 week group than in the 8 week group. Conclusions: Within the limitations of this study, we can conclude that repaired cementum after root planing was mainly acellular cementum and cementum tissue that matured to a shape similar to pristine cementum as the healing progressed from 8 to 24 weeks.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.2
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• pp.73-88
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• 2000

A series of analysis and experiment on the fishing gear and method of the existing midwater pair trawl net with 12,800mm of maximum mesh size is carried out to determine the most effective shape factor. As the first step of this study, the fishing gear and method for the existing net are analyzed to solve problems, such as being low of the net height by increasing the towing speed, twist of net pendant and twine, suspension of float between knots of mesh. etc. Standing on these results, the existing net are modified by very effective shape based on the theory and technology designing the fishing gear. Also, the model experiment is carried out to determine the most effective shape factor of the modified net in the circulation water channel. The obtained results can be summarized as follows : 1. On the length of net pendants(No.2 and No.3) connected with side line, opening efficiency of net with length 8.0cm of net pendant is the greatest and in the order of 11.5cm, 15.0cm. 2. On the number of the net pendant, opening efficiency of net with 4 lines of net pendant is the greatest and in the order of 3 lines, 2 lines. Center part of side panel is pushed out backward, and the pushed length is increasing by increasing flow speed. 3. On the sinking force, opening efficiency of the net is increasing by increasing sinking force. And opening efficiency shows almost the same when sinking force is greater about 1.5 times than that of the existing net in case of the net with 3 lines of net pendant, and about 1.6 ~ 1.7 times than that of the existing net in case of the net with 2 lines.