• Journal of Auto-vehicle Safety Association
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• v.10 no.4
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• pp.7-12
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• 2018

Injury mechanisms of lower extremity injuries in motor vehicle accidents are focused on fractures, sprains, and contusions. The purpose of this study is to evaluate the analysis of lower extremity injury mechanism in occupant motor vehicle accident by using Hospital Information System (HIS) and reconstruction program, based on the materials related to motor vehicle accidents. Among patients who visited the emergency department of Wonju Severance Christian Hospital due to motor vehicle accidents from August 2012 to February 2014, we collected data on patients with agreement for taking the damaged vehicle's photos. After obtaining the verbal consent from the patient, we asked about the cause of the accident, information on vehicle involved in the accident, and the location of car repair shop. The photos of the damaged vehicle were taken on the basis of front, rear, left side and right side. Damage to the vehicle was presented using the CDC code by analytical study of photo-images of the damaged vehicle, and a trauma score was used for medical examination of the severity of the patient's injury. Among the 1,699 patients due to motor vehicle crashes, 88 (5.2%) received a diagnosis of lower extremity fracture and 141 (8.3%) were the severe who had ISS over 15. Nevertheless during 19 months for research, it was difficult to build up in-depth database about motor vehicle crashes. It has a limitation on collecting data because not only the system for constructing database about motor vehicle crash is not organized but also the process for demanding materials is not available due to prevention of personal information. For accurate analysis of the relationship between occupant injury and vehicle damage in motor vehicle crashes, build-up of an in-depth database through carrying out various policies for motor vehicle crashes is necessary for sure.

• Journal of Trauma and Injury
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• v.24 no.1
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• pp.18-24
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• 2011

Purpose: Missing cervical pathology after injury may lead to disability and influence long-term survival. Controversies continue to evolve concerning the initial screening methods used to predict cervical spine injury. Through a retrospective chart review, we attempted to analyze and propose factors predictive of cervical trauma. Methods: Of all the patients who had visited the Emergency Department of Korea University, from January 2009 to December 2009, a retrospective review of the clinical records of the 217 patients who had undergone cervical spine computed tomography was done. We investigated whether we could predict the need for cervical spine computed tomography shortly after presentation in trauma patients by comparing the group with fractures and group without fractures and by finding risk factors showing significant differences between the two groups that might be used as guides in decision making. Results: Of the 217 subjects who underwent cervical spine computed tomography scans, 33 were identified with fractures of the cervical spine while 184 were not. The most common mechanisms of trauma, in order, for those with fractures were falls, followed by traffic accidents. We found that the injury severity score, multiple injuries, a high-energy injury mechanism, neurologic deficit, and pain and tenderness of the cervical spine showed statistically significant differences between the two groups. Conclusion: Fractures of the cervical spine that are not observed with simple radiography occur with a relatively high frequency in trauma patients. Consideration should be given to the risk factors for cervical spine fracture, and if pertinent, cervical spine computed tomography should be performed with speed for early diagnosis of cervical spine fractures.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.11
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• pp.505-513
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• 2006

The present study investigated the influence of the content of $Al_2O_3+Y_2O_3$ sintering additives on the microstructure, mechanical and electrical properties of the pressureless-sintered $SiC-ZrB_2$ electroconductive ceramic composites. Phase analysis of composites by XRD revealed mostly of ${\alpha}-SiC(4H),\;ZrB_2,\;{\beta}-SiC(15R)$ and In Situ $YAG(Al_5Y_3O_{12})$. The relative density and the flexural strength showed the highest value of 86.8[%] and 203[Mpa] for $SiC-ZrB_2$ composite with an addition of 8[wt%] $Al_2O_3+Y_2O_3$ as a sintering aid at room temperature respectively. Owing to crack deflection and crack bridging of fracture toughness mechanism, the fracture toughness showed 3.7 and $3.6[MPa{\cdot}m^{1/2}]\;for\;SiC-ZrB_2$ composites with an addition of 8 and 12[wt%] $Al_2O_3+Y_2O_3$ as a sintering aid at room temperature respectively. Abnormal grain growth takes place during phase transformation from ${\beta}-SiC\;into\;{\alpha}-SiC$ was correlated with In Situ YAG phase by reaction between $Al_2O_3\;and\;Y_2O_3$ additives during sintering. The electrical resistivity showed the lowest value of $6.5{\times}10^{-3}[({\Omega}{\cdot}cm]$ for the $SiC-ZrB_2$ composite with an addition of 8[wt%] $Al_2O_3+Y_2O_3$ as a sintering aid at room temperature. The electrical resistivity of the $SiC-ZrB_2$ composites was all positive temperature coefficient(PTCR) in the temperature ranges from $25[^{\circ}C]\;to\;700[^{\circ}C]$. The resistance temperature coefficient showed the highest value of $3.53{\times}10^{-3}/[^{\circ}C]\;for\;SiC-ZrB_2$ composite with an addition of 8[wt%] $Al_2O_3+Y_2O_3$ as a sintering aid in the temperature ranges from $25[^{\circ}C]\;to\;700[^{\circ}C]$. In this paper, it is convinced that ${\beta}-SiC$ based electroconductive ceramic composites for heaters or ignitors can be manufactured by pressureless sintering.

• Journal of the Mineralogical Society of Korea
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• v.21 no.1
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• pp.67-83
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• 2008

The sericite ore deposits formed in the Precambrian granitic rock at the Bonghwa area, Kyungsangbuk-do, South Korea. The geochemical and mineralogical characteristics of sericite occurred in Daehyun and Seonghwang mine were analyzed using petrographic microscope, XRD, EPMA, XRF and ICP. An alteration mechanism was also studied. Sericitization occurred within the granitic rock by hydrothermal alteration. From the careful study on the occurrence and mineral assemblage, four alteration zone were clearly identified. These zones reflect progressive hydrothermal alteration process. All sericites belong to $2M_1$ polytype and their mineralogical and geochemical properties are close to illite. The sericite ores show various colors, but the characteristics of major element compositions and crystal structures are not different. The trace element analysis, however, indicates that the difference in color attribute to the abundance of Cr and Ti: bluish green colored sericite are enriched in Cr and blackish green colored sericite enriched in Ti. The formation of sericite ore deposit in the granitic rocks are closely relate to fracture system such as fault and joint. It is considered that the sericite ore deposits in this area were formed by very simple hydrothermal alteration occurred along the fracture zones in granitic rocks with absence of other hydrothermally altered minerals such as kaolin and pyrophyllite.

• Journal of Veterinary Clinics
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• v.19 no.1
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• pp.49-54
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• 2002

Korean safflower (Carthami Flos) seed has been known to have healing effects on both bone fracture and osteoporosis. On the base of such a notice, this experiment was carried out to explore the effects of safflower seed on bone formation and bone repair. In addition, the healing mechanism was evaluated by analysing serum after feeding the seed to experimental. animals. The effect of Korean safflower seed were evaluated with 40 rats,3-month old. Forty Sprague-Dawley rats composed of 20 male and 20 female were underwent unilateral tibial defect and then fastened with unilateral fixators. The operated rats were divided into two groups depending on the composition of diet, such as positive control group fed normal diet (C-OP group) and safflower seed group fed 30% of safflower seed diet and 70% of normal diet (S-OP group). Postoperative radiographys were taken once in 2 weeks to evaluate callus formation for operated groups. In addition, a possible protein spots involved in bone recovery were examined using 2-Dimensional Gel Electrophoresis (2-DE). The comparison of the radiography between C-OP and S-OP group were showed that the safflower seed diet appeared to stimulate the formation of callus in the rat. On the images of 2-BE, it was able to identify possible five protein spots, having pl from 4 to 5 and molecular weight range from 24 to 26 kDa, involved in bone formation and repair, since no differing protein spots were found the two between groups except the five spots. No differences were observed between two groups before operation, but clear and bigger protein spots were observed from the S-OP group compared with C-OP group on 6 and 9 weeks post operation. These protein spots were, however, showed similar sizes and densities between two groups in 12 weeks later. The transformation of protein spots was suggested that these protein spots were involved in bone formation and recovery, in addition safflower seed might induce the formation of factors and activate these factors. In conclusion, this study suggest that safflower seed influence a variety of factors in the course of bone formation or the periods of remedy.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.3
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• pp.49-53
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• 2022

Ultra-thin glass (UTG) has been widely used in foldable display as a cover window for the protection of display and has a great potential for rollable display and various flexible electronics. The foldable display is under impact loading by bending and touch pen and exposed to other external impact loads such as drop while people are using it. These external impact loads can cause cracks or fracture to UTG because it is very thin under 100 ㎛ as well as brittle. Cracking and fracture lead to severe reliability problems for foldable smartphone. Thus, this study constructs finite element analysis (FEA) model for the pen drop test which can measure the impact resistance of UTG and conducts mechanical modeling to improve the reliability of UTG under impact loading. When a protective layer is placed to an upper layer or lower layer of UTG layer, stress mechanism which is applied to the UTG layer by pen drop is analyzed and an optimized structure is suggested for reliability improvement of UTG layer. Furthermore, maximum principal stress values applied at the UTG layer are analyzed according to pen drop height to obtain maximum pen drop height based on the strength of UTG.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.3
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• pp.72-83
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• 2022

This paper studied the effect on the microstructure, electrical properties, and compressive strength of cement mortar containing carbon fiber (CF) and steel fiber (SF), which are conductive materials. The resistivity of conductive fiber-reinforced cement mortar (FRCM) was measured using the 4-probe method, and the compressive strength was measured based on the compression test. Their performance was compared and reviewed with plain mortar (PM). Furthermore, the surface shape and composition of the fracture surface of the conductive FRCM were analyzed using a scanning electron microscope (SEM) and an energy disperse X-ray spectrometer (EDS). The results showed that the resistivity gradually increased as the curing time increased in all specimens, whereas the resistivity decreased significantly as the fiber volume fraction increased. Adding steel fibers up to 1.25% did not affect the resistivity of cement mortar considerably. On the contrast, the resistivity of carbon fiber was somewhat decreased even at low contents (ie, 0.1 to 0.3%), and thereafter, it was significantly decreased. The percolation threshold of the conductive CFRCM containing CF used in this experiment was 0.4%, and it is judged to be the optimum carbon fiber dosage to maximize the conductive effect while maintaining the compressive strength performance as much as possible. For the surface shape and composition analysis of conductive FRCM, the fracture surface was observed through SEM-EDS. These results are considered to be very useful in establishing the microstructure mechanism of reinforcing fibers in cement mortars.

• Journal of the Mineralogical Society of Korea
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• v.29 no.3
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• pp.131-139
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• 2016

Detailed knowledge on maskelynite, a glassy phase of plagioclase found in shocked meteorites and impact craters, is essential to understand a shock metamorphism. Here, we explore an inhomogeneous shock metamorphism in the lunar meteorite Mount DeWitt (DEW) 12007 with an aim to understand the formation mechanism of maskelynite. Most plagioclase grains in the DEW 12007 partially amorphized into maskelynite with a unidirectional orientation. Back-scattered electron (BSE) images of maskelynite show a remnant of planar deformation fracture possibly indicating that the maskelynite would be formed by solid-state transformation(i.e., diaplectic glass). Plagioclase with flow texture is also observed along the rim of maskelynite, which would be a result of recrystallization of melted plagioclase. Results of Raman experiments suggest that shock pressure for plagioclase and maskelynite in the DEW 12007 is approximately 5-32 GPa and 26-45 GPa, respectively. The difference in shock pressures between plagioclase and maskelynite can be originated from 1) external factors such as inhomogeneous shock pressure and/or 2) internal factors such as chemical composition and porosity of rock. Unfortunately, Raman spectroscopy has a limitation in revealing the detailed atomic structure of maskelynite such as development of six- or five-coordinated aluminum atom upon various shock pressure. Further studies using nuclear magnetic resonance spectroscopy are necessary to understand the formation mechanism of maskelynite under high pressure.

• Journal of the Korea Concrete Institute
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• v.22 no.5
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• pp.675-684
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• 2010

The reinforced concrete members are designed to fail in flexural to lead ductile fracture. In the building structures, the failure is typically imposed on beams to prevent damages in columns. However, progression of plastic collapse mechanism may ultimately develop, a plastic hinge at the bottem end of the first floor column, which then can be subjected to shear or bond finally due to large axial force and small shear span-to-depth ratio. In this study, 10 RC column specimens failed in shear after flexural yielding was investigated to determine the factors affecting the plastic hinge length. The findings of this study showed that the most effective factor affecting the plastic hinge length was an axial force. As an axial force increase, an axial strain and a ductility ratio were decreased obviously. The test also shows the observed plastic hinge length was about 0.8~1.2d and the this result has difference compared with forward research.

• Journal of Korean Orthopaedic Sports Medicine
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• v.2 no.2
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• pp.77-81
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• 2003

Purpose: The biomechanics and kinematics of knee joint were reviewed in this article. And then the common sports injuries were presented. Anatomy and Kinetics: None of the pairs of bearing surfaces in the knee joint is exactly congruent This allows the knee six degrees of freedom of motion. Tibiofemoral Kinematics: In flexion and extension, the axis of motion is not perpendicular to the medial-lateral plane of the joint, nor is it perpendicular to the axis of longitudinal rotation. This results in coupled varus angulation and internal rotation with flexion and in valgus angulation and external rotation with extension. Patellofemoral Articulation: Loads across the patellofemoral joint are indirectly related to the angle of knee flexion and directly related to the force generated within the quadriceps mechanism. Fractures of the Patella: Nonoperative treatment is indicated if the extensor mechanism is intact and if displacement of fragment is minimal. The specific type of internal fixation depends on the fracture pattern. It is important to repair retinaculum. Acute and Recurrent Patellar Instability: The degree of dysplasia and the extent of the instability play a large part in determining the success of nonoperative treatment. Patients who experience recurrent dislocations and patients with major anatomic variations require surgery to minimize their instability. Sports Injuries in School-age Atheletes: Patellar pain in young athletes groups a number of conditions, including Idiopathic Adolescent Anterior Knee Pain, Osgood- Schlatter Disease, and Sinding-Larsen-Johansson Disease.