• Journal of the Korea Institute of Building Construction
• /
• v.19 no.4
• /
• pp.289-297
• /
• 2019

Epoxy resin adhesives are currently used as adhesives in buildings. Epoxy resin adhesives, which are organic materials, generate harmful substances when producing adhesives, and toxic substances are high in the residential space after installation. In addition, a large amount of carbon monoxide generated from organic materials in the case of a building fire leads to personal injury. This study evaluates the feasibility of inorganic adhesives using pure inorganic materials such as magnesia, phosphate, and borax as inorganic adhesives to replace existing organic adhesives. As a result of the experiment on the selection of adequate phosphate and the characteristics of the addition rate of borax used as a retarder, the potassium phosphate monobasic was obtained as a suitable phosphate and the characteristics according to the borax addition rate were compared with the quality standard of KS F 4923 The hardening shrinkage and heat change rate satisfied the quality standards. The tensile strength was satisfactory when the borax addition rate was 4% or more, but the adhesive strength did not meet the quality standards. Further studies are needed to improve adhesion strength.

• Journal of Chest Surgery
• /
• v.38 no.9 s.254
• /
• pp.627-632
• /
• 2005

Background: The video-assisted thoracic surgery (VATS) with 2 mm thoracoscopy in primary spontaneous pneumothorax (PSP) was known to be unreliable in its accuracy and recurrence rate. We compared 10 mm VATS with 2 mm VATS in the results of operation. Material and Method: From Sept. 1998 to Dec. 2002, 176 cases (10 mm VATS; 73 cases, 2 mm VATS; 103 cases) of PSP were treated by VATS blob resection at Korea University Ansan Hospital. 10 mm thoracoscope, 5 mm port, and 5 mm instruments were used in 10 mm VATS group, and 2 mm thoracoscope, 2 mm ports and 2 mm instruments used in 2 mn VATS group. In the two groups, staples were inserted through 11.5 mm port for chest tube. Result: The mean follow-up duration was 20,8$\pm$16.1 months in 10 mm VATS group, and 13.9 $\pm$8.2 months in 2 mm VATS. The most common indication of operation was a recurrent pneumothorax ($34\%$) in 10 mm VATS and patient's desire ($40\%$) in 2 mm VATS, respectively. The operation time, number of staples used in operation, postoperative chest tube keeping days, postoperative total amount of drainage, and postoperative hospitalization days were statistically lower in 2 mm VATS. Other significant variables affecting the operation time in linear regression analysis were the number of staples that used in operation, the presence of pleural adhesion, and type of pleurodesis and thoracoscope used in operation. However, $R^2$ values were lower than 0.1. The postoperative recurrence rate was $2.7\%$ in 10 mm VATS and $2.9\%$ in 2 mm VATS. It was not significant statistically. Recurrent cases developed within 1 year in both groups but the difference was statistically insignificant. Conclusion: Although there were differences in follow-up duration between two groups, the operation time, number of staples that used in operation, postoperative chest tube keeping days, postoperative total amount of drainage, and postoperative hospitalization days were statistically lower in 2 mm VATS. And in 2 mm VATS, there were no technical difficulties during operation and no differences in recurrence rate from 10 mm VATS. As a result, we suggest that 2 mm VATS can be used in the treatment of PSP.

• Journal of Chest Surgery
• /
• v.30 no.10
• /
• pp.991-1000
• /
• 1997

Closed thoracostomy with UWSD* which is the most utilized procedure in chest surgery applies general thoracic disorders, trauma and after-thoracic surgery. The University hospital was involved on operating 2341 cases of closed thoracostomy with UWSD except chest tubing after-thoracic surgery for a full six years from January, 1991 to December, 1996. The rate of men and women out of the total 2341 cases was 3.5 : 1, the distribution by age showed that men were 36.6 $\pm21.0$ years old, women were $47.0\pm20.2$ years old and so that the total were 40.0 $\pm$ 20.5 years old. As for indication, spontaneous, secondary and traumatic pneumothorax were the most common, in addition to hemothorax hemopneumothorax, hydrothorax, hydropneumothorax, empyema, chylothorax. The most indwelling period of chest tubing is between eight and fourteen days for 974 cases and the average is 13.7 $\pm$ 6.3 days, The average drainage amount immediately after thoracostomy was 537 $\pm$ 88m1, and in 694 cases(46.0%), the drain amount was 201 ~ 500 ml. The rate of right and left tubing was 52.4 47.6, in 2071 cases(88.5%), the thoracostomy was the first chance and 2210 cases(94.4%) were treated with a single tube drainage. Almost all the patients complained of tube site pain, besides tube site infection, intercostal neuralgia, loss of tube function by the pleural adhesion, intrathoracic infection, incomplete reexpansion of defective lung, hemorrhage caused by the rupture of a blood vessel, subcutaneous emphysema, lung parenchymal rupture, diaphragmatic and intraabdominal trauma, reexpansionary pulmonary edema of one side lung and cellulitis were relapsed. 84.6% of all patients recovered with only clo ed thoracostomy and the rest of patient needed additional some necessary managements and so on to have successful results. There were two deaths(0.1%), caused by reexpansionary pulmonary edema, the cellulitis were complicated by thoracostomy with UWSD on an empyema patients to come to death(due to sepsis). t UWSD = under water seal drainage

• Journal of Periodontal and Implant Science
• /
• v.32 no.2
• /
• pp.429-455
• /
• 2002

There are numerous kind of materials and techniques to regenerate the periodontal tissue which has been lost due to destructive periodontal disease, including bone graft material. Many bone graft materials have been reported and among these materials, synthetic material has been developed fin the long time because of its sufficient supply economically. Calcium sulfate which was evaluated as including much calcium, has been used in the clinical field. In the dental field calcium sulfate has been used as bone graft material and Kim reported that improved bone formation and more amount of new attachment after grafting calcium sulfate. but, because calcium sulfate has the problem that it generates the heat in setting period and resolves fast, we need to evaluate the effect of the improved calcium sulfate on periodontal tissue. The present study evaluates the effect of paste type calcium sulfate on the epithelial migration, alveolar bone regeneration, cementum formation and gingival connective tissue attachment in intrabony defect in dogs. Four millimeter deep and four millimeter wide 3-wall defects were surgically created in the mesial or distal aspects of premolars or molars. the test group received paste-type calcium sulfate with a flap procedure and the control group underwent flap procedure only. Histologic analysis after 8 weeks of healing revealed the following results : 1. The length of epithelial growth(the distance from CEJ to the apical end of JE) was 0.52${\pm}$0.26mm in the control and 0.56${\pm}$0.25mm in the test group. there was no statistically significant difference between the two groups. 2. The length of connective tissue adhesion was 1.74${\pm}$1.06mm in the control and 1.28${\pm}$0.57mm in the test group. there was no statistically significant difference between the two groups. 3. The length of new bone was 2.01${\pm}$0.95mm in the control and 2.62${\pm}$0.81mm in the test group. there was no statistically significant difference between the two groups. 4. The length of new cementum was 1.86${\pm}$0.80mm in the control and 2.77${\pm}$ 0.86mm in the test group. there was a statistically significant difference between the two groups.(P<0.01) These results suggest that the use of paste type calcium sulfate in 3-wall intrabony defects has significant effect on new cementum formation , but doesn't have any significant effect on the prevention of junctional epithelium migration and new bone formation. Finally, the paste type calcium sulfate that is used in this study is suggested to be the material that can have a significant effect on the periodontal healing, if its biocompatibility is improved.

• Journal of the Korean Wood Science and Technology
• /
• v.45 no.5
• /
• pp.559-571
• /
• 2017

This study was conducted to determine the adhesive performances of plywoods affected by layering direction and the amounts of thermoplastic films. The face and back layers of veneer were hardwood species (Mixed light hardwood) and core layer veneer was radiata pine (Pinus radiata D. Don). Thermoplastic film used as adhesive were polypropylene (PP) film and polyethylene (PE) film. Thermal analysis and tensile strength were investigated on each films. As a result, the melting temperature of PP and PE films were $163.4^{\circ}C$ and $109.7^{\circ}C$, respectively, and the crystallization temperature were $98.9^{\circ}C$ and $93.6^{\circ}C$, respectively. Tensile strength and elongation of each films appeared higher on the width direction than length direction. Considering the characteristics of the thermoplastic films, the test for the amount of film used was carried out by layering film to the target thickness on veneer. The effecting of layering direction of film on plywood manufacturing was conducted by laminating in the length and width directions of the film according to the grain direction of veneer. Tensile-shear strength of plywood in wet condition was satisfied with the quality standard (0.7 MPa) of KS F 3101 when the film was used over 0.05 mm of PP film and over 0.10 mm of PE film. Tensile-shear strength of plywood after cyclic boiling exceeded the KS standard when PP film was used 0.20 mm thickness. Furthermore, higher bonding strength was observed on a plywood made with width direction of film according to grain direction of veneer than that of length direction of film. Based on microscopic analysis of the surface and bonding line of plywood, interlocking between veneers by penetration of a thermoplastic film into inner and cracks were observed.

• Tuberculosis and Respiratory Diseases
• /
• v.55 no.4
• /
• pp.353-360
• /
• 2003

Background : Although most patients with tuberculous pleurisy respond well to anti-tuberculous drugs, some are known to progress into severe pleural thickening which needs decortication despite adequate anti-tuberculous treatment. Therefore, the purpose of this study was to identify factors associated with the development of severe pleural thickening in patients who finally underwent pleural decortication in tuberculous pleurisy. Patients and Methods : From retrospective medical records review, 121 patients initially diagnosed as tuberculous pleurisy without initial pleural fluid loculation were enrolled between January 1998 and December 2002. They were separated into two groups: 85 patients in group 1 who improved by anti-tuberculous drugs only, and 36 patients in group 2 who had progressed into pleural adhesion and finally underwent pleural decortication despite adequate (more than 6 months) anti-tuberculous treatment. Results : Males were more common in group 2 (M/F=31/5) than in group 1 (M/F=53/32) (p=0.010). Group 2 patients tended to have lower pleural fluid glucose level ($58{\pm}4$ mg/dL) than group 1 ($89{\pm}3$ mg/dL) (p=0.001) and higher pleural fluid adenosine deaminase level ($86{\pm}5$ IU/L) than group 1 ($76{\pm}3$ IU/L), (p=0.038). There were no significant differences in age, symptom duration, pleural fluid amount, or pleural fluid LDH level between groups 1 and 2. Conclusions : There was a relative risk of tuberculous pleurisy progression into severe pleural thickening which needed decortication in the case of male patients, low pleural fluid glucose or high adenosine deaminase level. But further, large-scale, prospective studies should be investigated.

• Journal of the Korean Society of Radiology
• /
• v.17 no.3
• /
• pp.441-447
• /
• 2023

Lead(Pb), which is currently mainly used for shielding purposes in the medical radiation, has excellent radiation shielding functions, but is continuously exposed to radiation directly or indirectly due to the harmfulness of lead itself to the human body and the inconvenience caused by its heavy weight. Research on shielding materials that are human-friendly, lightweight, and convenient to use that can block risks and replace lead is continuously being conducted. In this study, based on the commonly used polyethylene terephthalate (PET) film and the fabric material used in actual radiation protective clothing, a multi-layer thin film was realized through sputtering and vacuum deposition of bismuth, tungsten, and tin, which are metal materials that can shield radiation. Thus, a shielding film was produced and its applicability as a radiation shielding material was evaluated. The radiation shielding film was manufactured by establishing the optimized conditions for each shielding material while controlling the applied voltage, roll driving speed, and gas supply amount to manufacture the shielding film. The adhesion between the parent material and the shielding metal thin film was confirmed by Cross-cut 100/100, and the stability of the thin film was confirmed through a hot water test for 1 hour to measure the change of the thin film over time. The shielding performance of the finally realized shielding film was measured by the Korea association for radiation application (KARA), and the test conditions (inverse wide beam, tube voltage 50 kV, half layer 1.828 mmAl) were set to obtain an attenuation ratio of 16.4 (initial value 0.300 mGy/s, measured value 0.018 mGy/s) and damping ratio 4.31 (initial value 0.300 mGy/s, measured value 0.069 mGy/s) were obtained. by securing process efficiency for future commercialization, light and shielding films and fabrics were used to lay the foundation for the application of films to radiation protective clothing or construction materials with shielding functions.

• Economic and Environmental Geology
• /
• v.56 no.6
• /
• pp.697-714
• /
• 2023

The Tracksite of Cretaceous Dinosaurs and Pterosaurs in Jeongchon, Jinju was discovered in late 2017 during the construction of the Ppuri industry complex. This site is a natural heritage site with a high paleontological value, as it preserves fossils of various types of dinosaurs, pterosaurs, and animal traces at a dense concentration. In this study, we surveyed that physical weathering such as joint, crack, scaling, exfoliation, and fragmentation occurred through field research in the fossil site, and conducted basic research on conservation science to reduce the damage. To this end, among the eight levels identified after excavation, the rocks of Level 3, which yielded a large number of theropod footprint fossils, and Level 4, which yielded pterosaur footprint fossils, were analyzed for material characteristics and evaluation of the effectiveness of consolidation and adhesion. This results showed that the rocks in the Level 3 stratum were dark gray siltstone and the rocks in the Level 4 stratum were dark gray shale, which contained a large amount of calcite and were composed of quartz, plagioclase, mica, alkali feldspar, and other clay minerals, which are likely to be damaged by rainfall under external conditions. As a result of conducting an artificial weathering experiment by dividing the probationary sample into four groups: untreated, consolidation treatment, anti-swelling treatment, and adhesive treatment, the consolidation and the swelling inhibitor showed an effect immediately after treatment, but did not show a blocking effect under a freezing-thawing environment. The adhesive showed that the adhesive effect was maintained even under freezing-thawing conditions. In order to preserve the fossil sites at Jeongchon in the future, in addition to temporary measures to block the inflow of moisture, practical measures such as the construction of protective facilities should be prepared.