• Journal of Welding and Joining
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• v.23 no.5
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• pp.20-24
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• 2005

Due to the difficulties associated with the supply of steel plates, hot rolled coil (Steel grade: SM490A) is considered fur structural materials in replace of the existing SWS50A-M1. However, it is found that SM490A exhibits a significant anisotropy in terms of impact energy with respect to transverse and longitudinal directions. In this study, an experimental investigation is carried out to examine the relationship between the anisotropy in impact values and the fatigue strengths of SM490A with respect to the rolling direction of test specimens. All test specimens failed around 1,500,000 cycles regardless of the test specimen direction. Therefore, it is found that the anisotropy in impact energy is not related to the fatigue strength of the materials considered in this study. However, the transverse direction specimen showed more rapid brittle fracture mode compared to that of longitudinal direction specimen, and this appears to be related to the lower impact values in transverse direction.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.3
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• pp.455-463
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• 2003

The aim of this study is to investigate the hydrogen embrittlement of Zr-2.5Nb CANDU pressure tube at room temperature. The transverse tensile and fracture toughness tests were performed at various hydrogen concentrations using transverse tensile specimens and CCT (curved compact tension) specimens. These specimens were directly machined from the pressure tube retaining original curvatures. Based on the results of these tests. the hydrogen embrittlement phenomenon was clearly observed and fracture toughness parameters of Zr-2.5Nb pressure tube materials such as, $K_{J(0.2)}$.$J_{ML}$.dJ/da, were dramatically decreased with the increasement of the hydrogen concentration. From microscopic observation by SEM and TEM, it was also revealed that various shapes dimples, fissures and quasi-cleavage were found at the hydrogen-absorbed materials with hydrides while traditional shape dimples were generally located at the as-received materials Through the comparison of the hydride and fissure lengths with the hydrogen concentration the new evaluation method of hydrogen embrittlement was suggested.

• Journal of Mechanical Science and Technology
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• v.16 no.8
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• pp.1064-1071
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• 2002

Stainless steel pipe of type 304 the with a wall thickness of 26.9 mm and the outer diameter 406.4 mm is welded by manual arc welding process. Mechanical properties and fracture toughness of type 304 stainless steel are investigated in the temperature ranging from room temperature to -162$^{\circ}C$ The results obtained are summarized as follows. The tensile strength noticeably increases as the temperature becomes lower while the yield strength is relatively insensitive to temperature. The Charpy impact energy and CTOD values become higher in the case that crack propagation direction is aligned to the transverse axis upon the rolling direction than longitudinal direction. The drop of fracture toughness is associated with the noticeable diminution of plastic component as temperature seduces from room temperature to -162$^{\circ}C$ .

• Journal of Korean Neurosurgical Society
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• v.43 no.1
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• pp.31-33
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• 2008

We present a rare case of fracture-dislocation at the level of the first sacral (S1) and second sacral (S2) vertebrae. The S1 was displaced forward into the pelvic cavity and was located just in front of the S2. Because the patient also had extensive neurological injury to the lumbar plexus and instability of the pelvic ring, surgery to stabilize the pelvis and to decompress the lumbar plexus was performed. The surgery was successful and the patient experienced marked improvement in neurological function.

• Laser Solutions
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• v.2 no.1
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• pp.61-67
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• 1999

This study introduces the new concept in the evaluation criteria of the $CO_2$ laser Tailored Blank weldability, The materials used are 0.7mm, 1.5mm thick low carbon automotive galvanized steels. Welding tests were conducted for both similar thickness(0.7mm-0.7mm, 1.5mm-1.5mm) and dissimilar thickness(0.7mm-1.5mm) cases. The criteria developed for optimum welding conditions were based on relationship between results of die press forming test, weld transverse tensile test Erichsen test and weld penetration measurements. Application of the developed criteria(fracture ratio, strength ratio and D/To) in obtaining optimum welding condition revealed that a weld which satisfied any of the criteria did not fracture during actual die press test.

• Journal of Korean Foot and Ankle Society
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• v.16 no.4
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• pp.270-275
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• 2012

There may be complications after comminuted or intraarticular calcaneal fracture regardless of the initial treatment. Transcalcaneal talonavicular dislocation is rarely reported severe form of calcaneal fracture. We experienced a neglected transcalcaneal talonavicular subluxation case, who had been treated for intraarticular calcaneal fracture conservatively. Subtalar distraction bone block fusion was done for calcaneal malunion with talonavicular subluxation. Inspite of successful subtalar fusion, pain was persisted because of talonavicular re-subluxation with arthritis and calcaneocuboid arthritis. So, second operation, the talonavicular and calcaneocuboid fusion, was done. After union achieved, the patient's foot pain was improved. Calcaneal malunion combined with talonavicular subluxation and unstable transverse tarsal joint, such as this case, initial triple arthrodesis could be considered.

• The Korean Journal of Ceramics
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• v.1 no.4
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• pp.197-203
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• 1995

Nearly fully dense PZT samples both with tetragonal and with morphotropic phase boundary compositions were prepared by the conventional powder processing and sintering. A micro-indentation technique was used to evaluate the dependence of fracture toughness on remanent polarization, crack length and the direction of crack propagation. The result shows that the toughness increases with the remanent polarization along the poling direction and decreases in the transverse direction. The dependence of toughness on the remanent polarization is neither symmetric nor linear but rather shown to be saturated quickly with the increase in remanent polariztion. R-curve behaviors are observed in both poled and unpoled samples. Sequential SEM and XRD studies on annealed, poled, ground, fractured and etched samples show that domain switching is evident as a viable toughening mechanism but might depend upon the rate of crack propagation. Grain bridging is also observed as one of the active toughening mechanisms.

• Journal of Dental Anesthesia and Pain Medicine
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• v.18 no.3
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• pp.183-187
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• 2018

Complex cervical spine fractures are a serious complications of maxillofacial trauma and associated with high mortality and neurological morbidity. Strict vigilance in preventing further insult to the cervical spine is a crucial step in managing patients who are at risk for neurologic compromise. We report a rare case of a right transverse process of atlas fracture with right-sided vertebral artery injury that was associated with a comminuted fracture of the body and angle of the mandible, which restricted mouth opening. Airway management was performed by an awake fiber-optic nasotracheal intubation, where neck movement was avoided with a cervical collar. Vertebral artery injuries may have disastrous consequences, such as basilar territory infarction and death, and should be suspected in patients with head and neck trauma. After mandibular plating, the patient was on cervical collar immobilization for 12 weeks and anti-coagulant therapy.

• Journal of Korean Foot and Ankle Society
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• v.22 no.4
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• pp.170-172
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• 2018

An ankle sprain is a relatively common sports-related injury but a severe open ankle sprain (SOAS) is very rare. A 27-year-old female athlete was injured during running and was hospitalized because of an inversed ankle injury with an open wound. She was diagnosed initially with an open-avulsion fracture at the tip of the fibula with an anterior talofibular ligament tear. The patient was finally diagnosed with SOAS from the surgical findings and literature review. SOAS should also be considered if there is a transverse open wound at the time of an ankle injury.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.11 no.1
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• pp.243-248
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• 1989

This is a report of 2 cases on old maxilla fractures accompanied with sagittal palatal fracture and severe malocclusion. We treated them by using of classic Le Fort I osteotomy and modified Le Fort I osteotomy along the old fracture lines satisfactorily. The results obtained from treatment are as follows : 1. Careful examination and correct care on sagittal palatal fracture should be need during initial diagnosis and emergency care of maxilla fracture showed malocclusion. 2. Although early definite treatment of maxilla injuries is difficult due to major organ injuries associated with accident, the positive effort to induce normal occlusion is always necessary as soon as possible. 3. In the cases of malocclusion due to transverse discrepancy of maxillary dentition associated with injury as like as our cases, classic and modified Le Fort I osteotomy and rigid internal fixation were useful to correct occlusion, to ease operation and return normal functions early.