• The korean journal of orthodontics
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• v.28 no.1 s.66
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• pp.75-83
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• 1998

This study was done to recognize the importance of errors in measurements of cephalometric radiograph and to find the anatomical structures those need special care to select as a reference points through the detection of the systematic errors and estimation of random errors. For this purose, 100 cephalometric radiographs were prepared by usual manner and 61 reference points, and 130 measurement variables were established. Measurement errors were detected and estimated by the comparison of the 25 randomly-selected samples for repeated measurements with the main sample. The following results were obtained : 1. In comparison of the repeated measurements, there were statistical significant differences in 24 variables which were 18.4% of 130 total variables. 2. The frequency of the difference in identification of the reference points between the repeated measurements was very high in the root apex of upper incisor(as), the most posterior wall of maxilla(tu), soft tissue nasion(n'), soft tissue frontal eminence(ft), and ad3 in airway. 3. After correction of reference points marking until the level of below 5% significance, the range of random errors were from 0.67 to 1.71 degree or mm. 4. The variable shown the largest random error was the interincisal angle(ILs-ILi). 5. Measurement errors were mainly caused by the lack of precision in anatomic definitions and obscure radiographic image. From the above results, the author could find the high possibility of errors in cephalometric measurements and from this point, we should include error analysis in all the studies concerning measurments. In is essential to have a concept of error analysis not only for the investigator but also for a reader of other articles.

• Journal of Periodontal and Implant Science
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• v.33 no.4
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• pp.615-624
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• 2003

The most accurate method to assess bone level is the histometric measurement. However it causes discomfort in patients and damage to the regenerated tissues. in the present study, we used 4 type regenerative therapies, The present study evaluated the clinical reliability and accuracy of bone probing measurements and radiographic bone level in the assessment of bone level by comparing those results with histometric confirmed bone level. Twentyfour(24) intrabony defects(4${\times}$4mm 1-wall intrabony defects) were surgically created in the mandibular second and fourth premolars of 6 beagle dogs. The control group underwent a conventional flap operation. Experimental group I was treated with calcium phosphate glass only, and while experimental group 2 was treated with GTR and experimental group 3 was treated with calcium phosphate glass and GTR. The subjects were sacrificed 8 weeks after the operation and a bone probing measurements, radiographic measurement and histometric measurement was performed. The correlation between bone probing measurements(BP) and histometric measurement(HL), and radiographic measurement(RL) and histometric measurement(HL) were analyzed with Spearman's rank correlation analysis and the statistical significance with respect to the type of regenerative therapies was analyzed with the Kruskal Wallis test. The coefficient of correlation to HL was 0.73 for RL and 0.90 for BP. The type of regenerative therapies had no significant effect on the difference between HL and other measurements. The results of this study suggests that bone probing measurements most closely represents actual bone level. So bone probing measurements may be a good clinical method for assessing the hone level following any type of periodontal regenerative therapies.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.2
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• pp.228-239
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• 2007

Statement of problem: Following tooth loss, the edentulous alveolar process of maxilla is affected by irreversible reabsorption process, with progressive sinus pneumatization leads to leaving inadquate bone height for placement of endosseous implants. Grafting the floor of maxillary sinus by sinus lifting surgery and augmentation of autologous bone or alternative bone material is a method of attaining sufficient bone height for maxillary implants placement and has proven to be a highty successful. Purpose: This study was undertaken to clarify the morphometric characteristics of inferior maxillary sinus and alveolar process for installation of implants. Material and method: Nineteen skulls (37 sinuses, 10M / 9F) obtained from the collection of the department of anatomy and cell biology of Hanyang medical school were studied. The mean age of the deceased was 69.9 years (range 44 to 88 years). The distance between alveolar border and inferior sinus margin at each tooth, the height of alveolar process and the thickness of cortical bone of the outer and inner table of alveolar process and the inferior wall of maxillary sinus were measured. Results and Conclusion: 1. The septum of inferior maxillary sinus were observe 28 sides (76.%) and located at the third molar (52.6%) and the second molar (26.3%). The deepest points of inferior border of maxillary sinus were located the first or second molar. The distance between alveolar margin and the deepest point of inferior maxillary sinus is $9.7{\pm}4.9mm$. 2. The length of the outer table of alveolar process were $4.9\sim28.2mm$ and the shortest point was between the first and the second molors. The thickness of them were $0.9\sim3.2mm$. The length of the inner table of alveolar process were $7.4\sim25.8mm$ and the shortest point was between the first and the second molars. The thickness of the were $0.9\sim4.6mm$. The results of this study are useful anatomical data for installing of maxillary implants.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.6 no.6
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• pp.72-85
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• 2003

The purpose of this study is to establish the basis of the ecological restoration on the limestone mines in Korea, through the research of the revegetation measures of the disturbed slopes in Japanese limestone mines and the analysis of the case of Ibuki and Bukou limestone mines to realize the restoration works successfully. According to the number of mines to carry out the revegetation works increase every year, the revegetation area and amount of planting also go on increasing in Japan. In the small mines the environmental problem is not recognized seriously, but some mines have muchly invested in the revegetation of the damaged land by mines. Ibuki mine in Shiga-gen is practicing the four principles for the restoring of the revegetation in the disturbed slopes by mines. Firstly, the mean slope preserves $37^{\circ}$ in the last rock cut slopes. Secondly, the last rock cut slopes to rehabilitate are covered with the soil dressing 30cm high. Thirdly, the grasses in the mining area are digged up beforehand, and then they are reused to the revegetation works of rock cut slopes. Lastly, from the upper rock cut slopes the revegetation works begin, the process of the above are repeated, as the result, the restoring works will be completed. Upon the ground of these principles, the complex of the original vegetation and the native species seeding, that is, the revegetation technique of Ibuki have established. In the difficult area to revegetate, sodding works, heaping up vegetation-sack, seed-spraying, heaping up soil-sacks and planting works are adapted variously. Bukou mine in Saitama-gen try to maintain the revegetation, the screening and the stability of the enormous mining rock cut slope, and for these works, the activity of 'Chichibu Working Group of Rock Wall for Limestone Mines' contributes largely. The chief technique of the revegetation in Bukou mine is following; after the making the berm on the rock cut slopes, the soil dressing is filled in it, and the trees is planted for the screening of the rock cut slopes. They devide the rock cut slopes into four typical types, and choose the different ways to make the berm and fill the soil dressing in characteristic. Most of the planting trees are consist ofthe native species of Mt. Bukou through the stages of the nursery and transplantation. Not only the revegetation of the demaged land but also the breeding of the conservational plants also are their important business.

• Journal of the Korean Institute of Landscape Architecture
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• v.35 no.1 s.120
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• pp.1-8
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• 2007

The purpose of this study is to suggest the minimum distance needed between landscape trees and apartment buildings. in order for the trees to grow soundly and maintain constant growth. Therefore, this study investigated and analyzed the present conditions of the green-spaces contiguous to apartment buildings and the trees inside the apartment complex. The following general problems were identified : (1) the tree growth conditions, (2) the planting intervals, and (3) the planting methods in the apartment complexes. The method of this study was to survey areas, measure the trees and analyze the results. Ten apartment complexes located in Seoul were randomly selected for this study. To analyze the greens contiguous to the building of each apartment complex, the greens were divided into three types, including the front greens, the side greens, and the rear greens. The study surveyed the width of all contiguous greens and the distance from trees to my given building. Four representative sites were specifically investigated to measure the crown widths, heights, and diameters of the trees. These investigations were carried out over 3 months from August to December 2006. According to the results of the study, it was found that the greens are narrower in width and the more closer to a building. The study identified a correlation between the tree and the passage of time after the completion of construction of an apartment complex, showing that the malformation of the trees worsened as time passed. As a result of measuring the right crown and left crown width with the tree trunk as the center, a broad difference was found between coniform trees and trees that tend to branch out more. For example, the ratio of the width of the Acer palmatum is 1:6. However, the ratio of the Metasequoia glyptostroboide is 1:1.7. Based on the overall analysis, it was concluded that the maintained minimum width must be greater than one meter over the green space according to the 'Landscape Standard 2000'. However, that is only applicable to cases such as apartment buildings that present no obstacles. In conclusion having greens placed within one meter of width to a building is not an appropriate environment for the healthy growth of trees. To create sound green spaces, sustainable, long-term growth rate and size should be considered. It is necessary to prepare new standards for the computation of planting trees and the measurement of square landscapes. Wall greenery and shrubberies could be an alternative in the case of a narrow-width green space.

• Journal of Yeungnam Medical Science
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• v.13 no.2
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• pp.347-359
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• 1996

Adenoid cystic carcinoma is an uncommon histologic variant of adenocarcinoma which usually arises from the salivary, lacrimal, or other exocrine glands. Characteristics of adenoid cystic carcinoma are its potential for extending long distance submucosally and for perineural invasion. It grows slowly and may have a prolonged course before diagnosis and after treatment. Recently, we have experienced 2 cases of adenoid cystic carcinoma arising from main bronchus and trachea. One case was 58 years old female patient. Her symptoms were productive cough with dyspnea. She has been history of shortness of breath, wheezing and cough during 4 years, which was initially diagnosed as bronchial asthma. The tumor was located on the left main stem bronchus which was obstructed the lumen nearly complete, by CT demonstration. Tissue diagnosis was confirmed as adenoid cystic carcinoma by bronchoscopic biopsy. The patient underwent radiation to relieve a bronchial stenosis caused by her tumor. The patient has remained well and is asymptomatic without evidence of clinical recurrence. The other case was 25 year old female. She complained shortness of breath and inspiratory difficulty during sleep. The tumor was located in upper trachea, which protruded from the posterior wall of the trachea and obstructed the lumen nearly complete, by CT demonstration. Tissue diagnosis was confirmed as adenocystic carcinoma by rigid bronchoscopic biopsy. The patient was underwent operation for removal of the mass and received radiotherapy. The patient has remained well are following up now.

• 한국문화재보존과학회:학술대회논문집
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• 2001.11a
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• pp.27-34
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• 2001

Following the recommendations made by the cultural authorities the wooden cultural properties (WCP) had been treated with fire-retardants for fire protection. However, visual inspections of some of the WCPs treated with fire-retardants showed microbial decay. The work was extended to examine the micromorphological characteristics of the WCPs in a Buddhist temple which had been treated with fire-retardant. Microscopic examination showed the presence of typical soft rot cavities along the length of microfibrils in the secondary wall. Bacterial attack was also observed by scanning and transmission electron microscopy. It is interesting that the decay patterns observed in the Buddhist temple were very similar to those observed in the waterlogged woods. Presumably chemicals in the fire-retardants used rendered the wood susceptible to attack by soft-rot and bacterial decay by causing an increase in the moisture content of wood. Further studies are needed to investigate the effect of fire-retardants used currently on the hygroscopicity and the strength of wood materials in the WCPs. Microbial attacks caused degradation of the secondary cell walls and in some cases also of the middle lamella. In addition, the cell walls in the outer parts of wood were also degraded due to weathering, and cell separation occurred from total disintegration of the middle lamella.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.1
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• pp.92-100
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• 2018

Vortical systems are considered a main feature to sustain turbulence in a boundary layer through interaction. Such turbulent structures result in frictional drag and erosion or vibration in engineering applications. Research for controlling turbulent flow has been actively carried out, but in order to show the effect of vortices in a turbulent boundary layer, it is necessary to clarify the mechanism by which turbulent energy is transferred. For this purpose, it is convenient to demonstrate and capture phenomena in a laminar boundary layer. Therefore, in this study, the interactions of disturbed flow around a hemisphere on a flat plate in laminar flow were analyzed. In other words, a street of hairpin vortices was generated following a wake region formed after flow separation occurred over a hemisphere. Necklace vortices surrounding the hemisphere also appeared due to a strong adverse pressure gradient that brought high momentum fluid into the wake region thereby leading to an increase in the frequency of hairpin vortices. To mitigate the effect of these necklace vortices, local suction control was applied through a hole in front of the hemisphere. Flow visualization was recorded to qualitatively determine flow modifications, and hot-film measurements quantitatively supported conclusions on how much the power of the hairpin vortices was reduced by local wall suction.

• Journal of the Korean Wood Science and Technology
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• v.3 no.1
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• pp.3-15
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• 1975

How to stabilize wood against shrinking and swelling in variable atmospheric moisture conditions is important to the wood-using industry and a challenge to research. Polyethylene glycol stabilize wood by bulking the fiber. PEG also serve as a chemical seasoning agent, suppress decay in high concentrations, and have slight effect on physical properties, gluing or finishing. The study designed to determine the effect of PEG-400 on the dimensional stabilization of local hardwoods for wood carvings that could supply a greatly expanding tourist trade and making curved furniture parts, lamp stands and other decorative objects, and possible gunstock. The species examined were 6 species, Seo-Namoo (Carpinus laxiflora), Cheungcheung-Namoo (Cornus controversa), Gorosae-Namoo (Acer mono), Karae-Namoo (Juglans mandshurica), Jolcham-Namoo (Quercusserrata) and Sanbud-Namoo (Prunus sargentii), used as block of 5cm thick radially to the grain, 7cm wide tangentially, and 70cm long parallel to the wood grain. All these test piecies were conditioned above the fiber saturation point before impregnation. The stabilization effects were determined for PEG-400 treated woods in a 50 percent solution for 20 days. The following conclusions were obtained. PEG retentions increased with treating time. It was more effective to treat at 60$^{\circ}C$ than at room temperature. In degree of PEG-400 impregnation on species, Cheungcheung-Namoo havinglow specific gravity had the highest retentions, 68.77% but the lowest, 56.33% was shown in Jolcham-Namoo with high specific gravity. Specific gravity of treated wood increased considerably with effectiveness of polymer loading. The increases in specific gravity were 5.36 to 13.16 percent. The highest was Jolcham-Namoo, the lowest Karae-Namoo. On the dimensional stability, a 40 percent of effectiveness of polymer loading was just as effective as 60 percent in reduction in water absorptivity (RWA), antishrinkage efficiency (ASE) and antiswelling efficiency (AE), and from over 60 percent they increased more rapidly. Also species response varied considerably. ASE was 30.12 to 69.97 percent tangentially and 27.86 to 56.37 percent radially, AE 34.06 to 73.76 percent tangentially and 30.11 to 70.12 percent radially, and RWA 42.31 to 65.32 percent. No differences in volume swelling among the 6 species were observed. Its values were ranged from 14.98 to 19.55 percent and also increased with PEG retentions. On the mechanical properties, the strengths very much decreased with PEG-400 loadings as shown in Figure 12; that were 11.41 to 22.90 percent in compression, 21.61 to 34.35 percent in bending and 22.83 to 36.83 percent in tensile strength. PEG retention in cell wall was less than 1 percent and the most of PEG were immersed in cell lumen. Except for Korae-Namoo, effectivenesses of polymer loading were as much high as 61.58 to 75.02 percent. This is believed to be due to the effect of PEG-400 on excellant dimensional stability of treated woods.

• Journal of Chest Surgery
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• v.32 no.2
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• pp.206-210
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• 1999

We report here 2 cases of deep-seated mediastinitis combined with sternal osteomyelitis after tracheal reconstruction which were successfully treated with sternectomy, in-situ or free omental transfer, and pectoralis major myocutaneous flap. In case I, an 8 year-old boy with deep seated mediastinitis and sternal osteomyelitis that developed after anterior tracheoplasty through a standard midline sternotomy. In case II, a 50 year-old female patient with mediastinal abcess and sternal osteomyelitis that developed after resection and end-to-end anastomosis of the trachea through an upper midline sternotomy. Treatments consisted of drainage and irrigation followed by wide resection of the infected sternum, placement of the viable omentum into the anterior mediastinal space, and chest wall reconstruction with a pectoralis major myocutaneous flap. The omentum was transferred as an in-situ pedicled graft in case I and a free graft in case II. Both patients have recovered smoothly wit out any events and have been doing well postoperatively.