• Journal of Conservation Science
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• v.35 no.1
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• pp.71-80
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• 2019

This study examined the applicability of digital technologies based on three-dimensional(3D) scanning, modeling, and printing to the restoration of damaged artifacts. First, 3D close-range scanning was utilized to make a high-resolution polygon mesh model of a roof-end tile with a missing part, and a 3D virtual restoration of the missing part was conducted using a haptic interface. Furthermore, the virtual restoration model was printed out with a 3D printer using the material extrusion method and a PLA filament. Then, the additive structure of the printed output with a scanning electron microscope was observed and its shape accuracy was analyzed through 3D deviation analysis. It was discovered that the 3D printing output of the missing part has high dimensional accuracy and layer thickness, thus fitting extremely well with the fracture surface of the original roof-end tile. The convergence of digital virtual restoration based on 3D scanning and 3D printing technology has helped in minimizing contact with the artifact and broadening the choice of restoration materials significantly. In the future, if the efficiency of the virtual restoration modeling process is improved and the material stability of the printed output for the purpose of restoration is sufficiently verified, the usability of 3D digital technologies in cultural heritage restoration will increase.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.2
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• pp.67-74
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• 2010

A variation of temperature acting on a RC roof slab causes a change of stress in concrete since it expands during summer and is compressed during winter. This behavior repeats annually and makes an affection to the structural capacity of member for both serviceability and ultimate level. In this paper, a cyclic temperature loading variation is calculated by analyzing the weather data of Korea for 20 years. In addition, an experimental work is planned to find the long term effect of temperature variation. Six RC slab are made with same dimension. Test parameters are loading duration (10, 20, 30 year) and whether it has pre-damage or not. Observation of stiffness variations according to cyclic loading period shows that the serious stiffness drop happens after 10 year's cyclic loading at summer while after 30 year's loading at winter. From the fracture test about slabs damaged by long term cyclic loading, however, the capacity of member such as initial stiffness and maximum strength were not changed except yield strength according to the period of long term cyclic loading. The yield strength tends to decrease after 20 year's cyclic loading.

• The Journal of the Korean dental association
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• v.56 no.10
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• pp.572-580
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• 2018

Adequate access cavity is the key to achieving endodontic success. The aims of the access cavity can be considered as follows: 1) Creation of a smooth unimpeded pathway for instruments to canal orifices 2) Removal of the entire roof of the pulp chamber in order to inspect the pulp floor, 3) Preservation of natural tooth substance consistent with the above. Recently, contracted endodontic cavities based on minimally invasive endodontics has introduced. This has the benefit of preserving the pericervical dentin more than traditional access cavity with achieving long-term success. However, some studies reported controversial results regarding root canal detection, instrumentation efficacy (noninstrumented canal area, hard tissue debris accumulation, canal transportation, and centering ratio) as well as fracture resistance. Therefore, further studies are required for accepting contracted access cavity, and modified form of traditional and contracted access cavity could be considered.

• Journal of Korean Neurosurgical Society
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• v.55 no.4
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• pp.222-225
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• 2014

Traumatic intracranial aneurysms (TICAs) are rare and are associated with high rates of morbidity and mortality. TICAs usually result from head injuries caused by traffic accidents, industrial accidents, or gunshots. We report a traumatic aneurysm of the callosomarginal artery-cortical artery junction arising from a penetrating injury by scissors. A 51-year-old woman was admitted to our hospital after suffering a penetrating injury caused by scissors. Computed tomography (CT) and CT-angiography demonstrated a right orbital roof fracture, subarachnoid hemorrhage, frontal lobe hemorrhage, intraventricular hemorrhage, and a traumatic aneurysm of the right callosomarginal artery-cortical artery junction. We trapped the traumatic aneurysm and repositioned a galeal flap. Postoperative CT showed a small infarction in the left frontal lobe. Follow-up angiography two months later showed no residual aneurysm. We suggest that an aggressive surgical intervention be performed whenever TICA is diagnosed.

• Archives of Craniofacial Surgery
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• v.11 no.1
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• pp.33-36
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• 2010

Purpose: Brown's syndrome is characterized by the limited elevation in adduction from mechanical causes around the superior oblique tendon trochlea complex. In this particular case, post-traumatic facial deformity accompanied by Brown's syndrome was observed. We would like to report the satisfying cosmetic results obtained by reconstructing orbital roof and superior orbital rim and repositioning of zygoma. Methods: A 12-year-old patient was observed with facial deformity with strabismus in her right eye and orbital dystopia after the car accident and was eventually diagnosed with traumatic Brown's syndrome. Reconstructive surgeries could not be performed at the time of trauma due to the cerebral hemorrhage. At the second year after the trauma, a depressed fracture of the right orbital roof and superior orbital rim were reconstructed via the intracranial approach, and orbital dystopia was corrected via the zygoma triple ostectomy. In addition, a strabismus surgery was performed one year after her plastic surgery. Results: Facial deformity with orbital dystopia and strabismus was confirmed to be fully reconstructed after the surgery. Moreover, when the patient came in for a follow-up thirteen years after the operation, a developmental imbalance of the facial bones, diplopia, or any other surgical complications were not to be found. Conclusion: After the trauma, the patient with Brown's Syndrome accompanied by post-traumatic facial deformity, who went under the corrective surgeries after the meticulous examination and assessment pre-surgically, was able to acquire cosmetic satisfaction via those operations.

• Economic and Environmental Geology
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• v.35 no.4
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• pp.355-368
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• 2002

The multi-storied Daewonsa stone pagoda (Treasure No. 1112) in the Sancheong, Korea was studied on the basis of deterioration and geological safety diagnosis. The stone pagoda is composed mainly of granitic gneiss, partly fine-grained granitic gneiss, leucocratic gneiss, biotite granite and ceramics. Each rock of the pagoda is highly exfoliated and fractured along the edges. Some fractures in the main body and roof stones are treated by cement mortar. This pagoda is strongly covered with yellowish to reddish brown tarnish due to the amorphous precipitates of iron hydroxides. Dark grey crust by manganese hydroxides occur Partly, and some Part coated with white grey gypsum and calcite aggregates from the reaction of cement mortar and rain. As the main body, roof and upper part of the pagoda, the rocks are developed into the radial and linear cracks. Surface of this pagoda shows partly yellowish brown, blue and green patchs because of contamination by algae, lichen, moss and bracken. Besides, wall-rocks of the Daewonsa temple and rock aggregates in the Daewonsa valley are changed reddish brown color with the same as those of the pagoda color. It suggests that the rocks around the Daewonsa temple are highly in iron and manganese concentrations compared with the normal granitic gneiss which color change is natural phenomena owing to the oxidation reaction by rain or surface water with rocks. Therefore, for the attenuation of secondary contamination, whitening and reddishness, the possible conservation treatments are needed. Consisting rocks of the pagoda would be epoxy to reinforce the fracture systems for the structural stability on the basements.

• Archives of Plastic Surgery
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• v.34 no.6
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• pp.724-728
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• 2007

Purpose: The objective of this study is to prevent postoperative lower eyelid retraction and scleral show. There are several approaches for orbital rim reconstruction. But these techniques are sometimes difficult to perform, and have some merits and faults. Maybe most common unwanted and unpleasant result that we have experienced by subciliary incision preseptal approach is the lower eyelid retraction and the scleral show. Therefore, I want to find out the causes and the solutions for such complication. We must know the mechanics for those unpleasant result first of all. Methods: We conducted a comparison of postoperative photographs between retroseptal approach group and preseptal approach group, both with subciliary incision. In experimental retroseptal group, incision was applied at subciliary region. After elevating skin flap to preserve pretarsal muscle, not with muscle flap elevation, but direct oblique incision through the muscle, retroseptal dissection was applied to the ROOF and the septum. Fixating fracture line, periosteal and septal repair was followed by skin repair. The light compressive dressings and protection were kept in place for 7 days. The effectiveness of this operative method was made comparison with control group which the preseptal approach was applied to, by postoperative 2nd week and 2nd month. Results: Author's technique had been used in 20 patients and control group was composed of 50 patients over 19months period. There were better results in experimental group than in control group and all of experimental group had no complaint about the lower eyelid retraction and the scleral show. Conclusion: It must be known about the reason of the lower eyelid retraction and the scleral show induced by subciliary and preseptal approach. Mechanically it can be easily proved. And the solution maybe will be easier if we get more information about the mechanics. I recommend the retroseptal subciliary approach

• Journal of Trauma and Injury
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• v.19 no.1
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• pp.89-92
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• 2006

Penetrating facial wounds are uncommon and are usually life threatening because of the possibility of brain damage. There are three possible pathways for penetrating the cranium through the orbit: via the orbital roof, via the superior orbital fissure, or between the optic canal and lateral wall of the orbit. Brain injuries resulting from the penetrating wounds show extensive parenchymal damage, hemorrhage, and brain edema. Transorbital penetrating wounds can lead to diverse lesions of the optical apparatus, including the eye globe, the optical nerve, and the chiasm. Moreover, intracerebral structures may be hurt, and bleeding and infection may occur. Early diagnosis and prompt debridement are the fundamental factors affecting the outcome of a penetrating facial wound. An 87-year-old man was admitted to the emergency department with a grinder impacted into the medial aspect of the right eye. On presentation, the man was fully conscious with a Glasgow Coma Scale score of 15 and complained of a visual disturbance of the right eye. Computed tomography demonstrated a right orbital medial and inferior wall fracture, a frontal bone fracture, and a contusional hemorrhage in frontal lobe of the brain. A craniotomy with hematoma removal and repair of the orbital floor was done. He showed no neurological deficits except right visual loss. This appears to be the first report of a man with a penetrating facial wound caused by a grinder, who presented with a potentially disastrous craniocerebral injury that did not lead to any serious neurological seguelae.

• Geomechanics and Engineering
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• v.33 no.5
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• pp.477-486
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• 2023

In the studies on fault dislocation of tunnel, existing literatures are mainly focused on the problems caused by normal and reverse faults, but few on strike-slip faults. The paper aims to research the deformation and failure mechanism of a tunnel under strike-slip faulting based on a model test and test-calibrated numerical simulation. A potential faulting hazard condition is considered for a real water tunnel in central Yunnan, China. Based on the faulting hazard to tunnel, laboratory model tests were conducted with a test apparatus that specially designed for strike-slip faults. Then, to verify the results obtained from the model test, a finite element model was built. By comparison, the numerical results agree with tested ones well. The results indicated that most of the shear deformation and damage would appear within fault fracture zone. The tunnel exhibited a horizontal S-shaped deformation profile under strike-slip faulting. The side walls of the tunnel mainly experience tension and compression strain state, while the roof and floor of the tunnel would be in a shear state. Circular cracks on tunnel near fault fracture zone were more significant owing to shear effects of strike-slip faulting, while the longitudinal cracks occurred at the hanging wall.

• Geomechanics and Engineering
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• v.37 no.3
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• pp.293-306
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• 2024

Influenced by the alternating effects of dynamic and static pressure during the mining process of close range coal seams, the surrounding rock support of cross mining roadway is difficult and the deformation mechanism is complex, which has become an important problem affecting the safe and efficient production of coal mines. The paper takes the inclined longwall mining of the 10304 working face of Zhongheng coal mine as the engineering background, analyzes the key strata fracture mechanism of the large inclined right-angle trapezoidal mining field, explores the stress distribution characteristics and transmission law of the surrounding rock of the roadway affected by the mining of the inclined coal seam, and proposes a segmented and hierarchical support method for the cross mining roadway affected by the mining of the close range coal seam group. The research results indicate that based on the derived expressions for shear and tensile fracture of key strata, the ultimate pushing distance and ultimate suspended area of a right angle trapezoidal mining area can be calculated and obtained. Within the cross mining section, along the horizontal direction of the coal wall of the working face, the peak shear stress is located near the middle of the boundary. The cracks on the floor of the cross mining roadway gradually develop in an elliptical funnel shape from the shallow to the deep. The dual coupling support system composed of active anchor rod support and passive U-shaped steel shed support proposed in this article achieves effective control of the stability of cross mining roadways, which achieves effective control of floor by coupling active support and preventive passive support to improve the strength of the surrounding rock itself. The research results are of great significance for guiding the layout, support control, and safe mining of cross mining roadways, and to some extent, can further enrich and improve the relevant theories of roof movement and control.