• Journal of Biosystems Engineering
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• v.29 no.3
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• pp.251-260
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• 2004

As a basic experiment for robot hand for transplanting plug seedling, the experimental robot hand system which moves up and downward vertically, and allows hand blade to open and close was made. The system was constructed with the robot hand mechanism, the tray, the plug seedling, and the measuring equipments. The penetrating force and holding efficiency were analyzed according to the soil moisture and the variation of hand blade angle. The highest holding efficiency could be obtained at the penetrating angle of approximately from 0 to 0.36 degree and at the moisture content of soil from 71% to 75%. The external force acted on the robot hand should maximum force when the robot hand was penetrated to soil, minimum of approximately 30.4 N when the penetrating angle was 0$^{\circ}$ and moisture content was 66-70%. It was increased with increasing or decreasing the Penetrating angle from 0 degree and also with increasing or decreasing the moisture content of soil from 66-70%. For optimal design of the robot hand and manipulator, the external force acted on robot hand had to be based on the returning force of soil, when the robot hand was penetrated to the soil. In consideration of safety ratio, the appropriate external force seemed to be 39-49 N.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.2
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• pp.131-137
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• 2016

In this paper, a feasibility on a ground-penetrating radar for detecting subsurface cavities near buried pipes has been investigated. The experimental setup was implemented by employing an impulse ground-penetrating radar system, a xy Cartesian coordinate robot, an underground material filled tank, a metal pipe and a simulated cavity model. In particular, the simulated cavity model was constructed by packing Styrofoam chips and balls, which have both similar electrical properties to an air-filled cavity and a solid shape. Through typical three experiments, B-scan data of the radar have been acquired and displayed as 2-D gray-scale images. According to the comparison of B-scan images, we show that the subsurface cavities near the buried pipes can be detected by using the radar survey.

• Restorative Dentistry and Endodontics
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• v.26 no.1
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• pp.64-76
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• 2001

Despite the improvements in bond strengths of dentin adhesives and resin-modified glass ionomers, the marginal seal of cervical restorations remains a concern. Microleakage at poorly sealed margins can result in staining, post-operative sensitivity, pulpal irritation, and recurrent caries. The objective of this study was to evaluate the effect of surface penetrating sealant(SPS) on the microleakage of cervical restorations. 45 extracted human teeth were selected, and Class V preparations were prepared on the both buccal and lingual surface of the teeth to the following dimensions : 1.5mm axially, 3mm mesiodistally, and 3mm incisogingivally. After cervical restoration with composite resin, compomer, glass ionomer each restoration was treated as three methods: No Tx., Scotchbond Multipurpose Adhesive$^{\circledR}$, Fortify$^{\circledR}$. The sections were examined with a stereomicroscope to determine the extent of microleakage at enamel and dentin margins. The results of this study were as follows. 1. All groups showed some microleakage. 2. Gingival cavity wall with cementum margin showed significantly higher leakage value than occlusal cavity wall with enamel margin. 3. The group treated with SPS showed significantly lower leakage value than no treated group(p<0.05). But there is no difference between Fortify$^{\circledR}$ and Scotchbond Multipurpose adhesive$^{\circledR}$. The results of this study suggest that SPS are effective in reducing microleakage of class V restorations. But it is certain that some microleakage still occurred despite the application of SPS.

• Journal of Chest Surgery
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• v.5 no.2
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• pp.113-124
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• 1972

Clinical observations were performed on 150 cases of chest trauma, those were admitted and treated at the Department of Surgery, Korea University Woosok Hospital, during the past 8 years period from August 1965 to August 1972. 1. The ratio of male to female patient of chest trauma was 3.4:1 in male predominence and age from 20 to 50 occupied 62% of the total cases. 2. The most common cause of chest trauma was traffic accident in this series. Eighty-one cases[54%] were injured by traffic accident and total cases due to blunt trauma [non-penetrating injury] were 113 cases[75.4%]including the cases with traffic accident, and remaining 37 cases[24.6%] were due to penetrating injury including 25[16.6%] cases of stab wounds. 3. Hemopneumothorax were observed in 645/[96 cases] of the total cases, and etiologic distribution revealed 78.1% due to non-penetrating trauma and 20.8% due to penetrating injury. 4. Rib fracture was found in 50% of cases. Common injuries associated with rib fracture were lung, brain and liver. 5. Most common symptom was chest pain and respiratory difficulty, and common sign associated with chest injury was decreased respiratory sound and subcutaneous emphysema. 6. Conservative non-operative treatment was performed in 94 cases[62.6%] and 56 cases [37.4%] were treated with operative treatment including 31 cases[20.6%] with open thoracotomy. 7. Overall mortality was 9.3%[14 cases] and most common causes of death were due to brain edema,asphyxia and shock.

• Journal of Trauma and Injury
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• v.20 no.1
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• pp.47-51
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• 2007

Penetrating chest trauma caused by the components of one's own car is rare in motor vehicle accidents. We experienced two cases of penetrating chest injury caused by the sideview mirror of the patient's vehicle. One was a 25-year-old man. The sideview mirror penetrated the left chest, went through the diaphragm, and ruptured the spleen. He was in shock upon arrival at the emergency room. An emergency thoracotomy and laparotomy were done. The ruptured spleen was resected, the lung and the diaphragm were debrided and repaired, and the chest wall was reconstructed. The other patient was a 57-year-old male, who was transported to our emergency room with the sideview mirror of his truck stuck into his right chest wall as the result of an accident. He also had a right Bennet's fracture and an open fracture of the right tibia. Air had been sucked into the right pleural cavity through the wound. Multiple rib fractures and lung lacerations had also occurred. Removal of the sideview mirror, repair of the lacerated lung, and reconstruction of chest wall were done immediately. Both patients recovered without complication and were discharged.

• Imaging Science in Dentistry
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• v.48 no.4
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• pp.295-300
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• 2018

This report presents a clinical case of trauma due to assault with a knife, and describes the importance of using the correct imaging modality in cases of facial penetrating trauma involving the superficial and deep anatomical planes. Penetrating wounds in the maxillofacial region are rare and poorly reported, but can result in serious complications that are difficult to resolve and may compromise the patient's quality of life, especially when large blood vessels or other vital structures are involved. Thus, it is essential to determine the extent of the affected blood vessels and the proximity of the retained object to the anatomical structures. In this case, digital subtraction angiography was the imaging modality chosen. The use of appropriate imaging examinations allows a proper map of the surgical field, reducing the chances of vascular damage during the surgical procedure.

• Steel and Composite Structures
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• v.44 no.3
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• pp.339-351
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• 2022

A mortar-filled rectangular hollow structural section (RHS) can increase a structural section property as well as a compressive buckling capacity of a RHS member. In this study, the tensile performance of newly developed mortar-filled RHS members was experimentally evaluated with various connection details. The major test parameters were the type of end connections, the thickness of cap plates and shear plates, the use of stud bolts, and penetrating bars. The test results showed that the welded T-end connection experienced a brittle weld fracture at the welded connection, whereas the tensile performance of the T-end connection was improved by additional stud bolts inserted into the mortar within the RHS tube. For the end connection using shear plates and penetrating stud bolts, ductile behavior of the RHS tube was achieved after yielding. The penetrating bars increased load carrying capacity of the RHS. Based on the analysis of the load transfer mechanism, the current design code and test results were compared to evaluate the tensile capacity of the RHS tube according to the connection details. Design considerations for the connections of the mortar-filled RHS tubes were also recommended.

• Journal of Chest Surgery
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• v.53 no.5
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• pp.291-296
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• 2020

Background: We report our 10-year experience with traumatic peripheral arterial injury repair at an urban level I trauma center. Methods: Between January 2007 and December 2016, 28 adult trauma patients presented with traumatic peripheral arterial injuries. Data were retrospectively collected on demographic characteristics, the mechanism of injury, the type of vascular injury, and physiological status on initial assessment. The analysis also included the Mangled Extremity Severity Score (MESS), Injury Severity Score, surgical procedures, and outcome variables including limb salvage, hospital stay, intensive care unit stay, and postoperative vascular complications. Results: Four (14.3%) patients required amputation due to failed revascularization. MESS significantly differed between patients with blunt and penetrating trauma (8.2±2.2 vs. 5.8±1.3, respectively; p=0.005). The amputation rate was not significantly different between patients with blunt and penetrating trauma (20% vs. 0%, respectively; p=0.295). The overall mortality rate was 3.6% (1 patient). Conclusion: Blunt trauma was associated with higher MESS than penetrating trauma, and amputation was more frequent. In particular, patients with blunt trauma had significantly higher MESS than patients with penetrating trauma (8.2±2.2 vs. 5.8±1.3, respectively; p=0.005), and amputation was performed when revascularization failed in cases of blunt trauma of the lower extremity. Therefore, particular care is needed in making treatment decisions for patients with peripheral arterial injuries caused by blunt trauma.

• Journal of Trauma and Injury
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• v.32 no.4
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• pp.210-219
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• 2019

Purpose: Traumatic diaphragmatic injury (TDI) is no longer considered to be a rare condition in Korea. This study investigated differences in the prevalence of accompanying injuries and the prognosis in patients with traumatic diaphragmatic damage according to the mechanism of injury. Methods: We retrospectively reviewed the medical records of patients with TDI who were seen at a regional emergency medical center from January 2000 to December 2018. Among severe trauma patients with traumatic diaphragmatic damage, adults older than 18 years of age with a known mechanism of injury were included in this study. Surgery performed within 6 hours after the injury was sustained was defined as emergency surgery. We assessed the survival rate and likelihood of respiratory compromise according to the mechanism of injury. Results: In total, 103 patients were analyzed. The patients were categorized according to whether they had experienced a penetrating injury or a blunt injury. Thirty-five patients had sustained a penetrating injury, and traffic accidents were the most common cause of blunt injuries. The location of the injury did not show a statistically significant difference between these groups. Severity of TDI was more common in the blunt injury group than in the penetrating injury group, and was also more likely in patients with respiratory compromise. However, sex, the extent of damage, and the initial Glasgow coma scale score had no significant relationship with severity. Conclusions: Based on the findings of this study, TDI should be recognized and managed proactively in patients with blunt injury and/or respiratory compromise. Early recognition and implementation of an appropriate management strategy would improve patients' prognosis. Multi-center, prospective studies are needed in the future.

• Journal of Korean Neurosurgical Society
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• v.48 no.1
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• pp.73-78
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• 2010

Objective : Streptococcus pyogenes is a beta-hemolytic bacterium that belongs to Lancefield serogroup A, also known as group A streptococci (GAS). There have been five reported case in terms of PubMed-based search but no reported case of brain abscess caused by Streptococcus pyogenes as a result of penetrating skull injury. We present a patient who suffered from penetrating skull injury that resulted in a brain abscess caused by Streptococcus pyogenes. Methods : The patient was a 12-year-old boy who fell down from his bicycle while cycling and ran into a tree. A wooden stick penetrated his skin below the right lower eyelid and advanced to the cranium. He lost consciousness on the fifth day of the incident and his body temperature was measured as $40^{\circ}C$. While being admitted to our hospital, a cranial computed tomography revealed a frontal cystic mass with a perilesional hypodense zone of edema. There was no capsule formation around the lesion after intravenous contrast injection. Paranasal CT showed a bone defect located between the ethmoidal sinus and lamina cribrosa. Results : Bifrontal craniotomy was performed. The abscess located at the left frontal lobe was drained and the bone defect was repaired. Conclusion : Any penetrating lesion showing a connection between the lamina cribrosa and ethmoidal sinus may result in brain abscess caused by Streptococcus pyogenes. These patients should be treated urgently to repair the defect and drain the abscess with appropriate antibiotic therapy started due to the fulminant course of the brain abscess caused by this microorganism.