• Journal of Korean Neurosurgical Society
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• 제52권3호
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• pp.264-266
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• 2012

Injury to the bilateral internal branch of superior laryngeal nerve (ibSLN) brings on an impairment of the laryngeal cough reflex that could potentially result in aspiration pneumonia and other respiratory illnesses. We describe a patient with traumatic cervical injury who underwent bilateral ibSLN palsy after anterior cervical discectomy with fusion (ACDF). An 75-year-old man visited with cervical spine fracture and he underwent ACDF through a right side approach. During the post-operative days, he complained of high pitched tone defect, and occasional coughing during meals. With a suspicion of SLN injury and for the work up for the cause of aspiration, we performed several studies. According to the study results, he was diagnosed as right SLN and left ibSLN palsy. We managed him for protecting from silent aspiration. Swallowing study was repeated and no evidence of aspiration was found. The patient was discharged with incomplete recovery of a high pitched tone and improved state of neurologic status. The SLN is an important structure; therefore, spine surgeons need to be concerned and be cautious about SLN injury during high cervical neck dissection, especially around the level of C3-C4 and a suspicious condition of a contralateral nerve injury.

• 동력기계공학회지
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• 제12권3호
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• pp.50-54
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• 2008

Various Sialon ceramics were fabricated by hot-pressing mixtures of $Si_3N_4$ with additive $Y_2O_3$ and $Al_2O_3$. The polished specimen of SiAlON $I{\sim}III$ went on increasing in strength by heat treatment, heat treated non-polished specimen were similar or up to polished specimen in strength. The polished specimen of both SiAlON IV and V showed a very high strength, but were not Increasing of strength by heat treatment. All specimens were fractured on the surface and at the inner flaws. Surface fractures were initiated from the polished surface flaw and corner flaw. Inner fractures were initiated from an internal defect.

• 한국자동차공학회논문집
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• 제23권5호
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• pp.471-477
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• 2015

In this study, the property of crack propagation and growth at high tension steel plate existed with center crack is investigated. The behaviors of fracture mechanics due to existence or not of hole near the center crack in specimen and the length of crack length are investigated when the load is applied at the one side end of specimen. Stress, deformation and deformation of this specimen are evaluated through simulation analysis. By the analysis results at this study, stress intensity factors are obtained. The damage happened at machine or structure with crack or defect can be estimated on the basis of study results.

• 한국세라믹학회지
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• 제39권5호
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• pp.446-451
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• 2002

지르코니아/알루미나 복합분말의 분무건조로 제조된 과립들의 형상과 성형시 과립 경계면 파괴에 분말의 분산 정도, 결합제의 종류, 그리고 고형분말 함량이 미치는 영향을 관찰하였다. 구형의 과립은 복합분말 슬러리가 완전 분산이 되지 않고 약간의 floc을 형성하고 결합제로서 Polyvinyl Pyrrolidone(PVP)을 사용했을 때 얻어졌다. PVP를 결합제로 사용하고 분말함량이 32.5 vol%인 슬러리로 분무건조한 분말은 성형시 과립경계면이 파괴되어 소결밀도는 99.7%이었고 굴곡강도는 850Mpa이었다.

• 대한기계학회논문집A
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• 제26권9호
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• pp.1746-1752
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• 2002

Fatigue fracture in machine components is produced by surface micro-crack from stress concentration area such as notch and material defect. It is difficult to predict the remaining fatigue lift of mechanical components because the surface micro-crack on critical area initiates and grows with statistical distribution. Plane bending fatigue tests were carried out on the plain specimen of Al 2024-T3 and the initiation and growth behavior of surface micro cracks were observed. The statistical distribution of surface length of multiple micro cracks and their maximum length were investigated. The maximum surface crack length distributions were analyzed on the basis of the statistics of extremes in order to examine the prediction of remaining life.

• 대한기계학회논문집A
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• 제33권11호
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• pp.1187-1194
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• 2009

During the last decade, possibility of flaw occurrences has been rapidly increased world-widely as the increase of operating times of petro-chemical facilities. For instance, from a recent in-service inspection, three different sized surface cracks were detected in welding parts of a spherical oxygen holder in Korea. While API579 code provides corresponding engineering assessment procedures to determine crack driving forces, in the present work, numerical analyses are carried out for the cracked oxygen holder to investigate effects of complex geometry, analysis model and residual stress. With regard to the detailed finite element analysis, stress intensity factors are determined from both the full three-dimensional model and equivalent plate model. Also, as an alternative, stress intensity factors are calculated for equivalent plate model by employing the noted influence stress function technique. Finally, parametric structural integrity evaluation of the cracked oxygen holder is conducted in use of failure assessment diagram method, J/T method and DPFAD method. Effects of the geometry and so forth are examined and key findings from the simulations are fully discussed, which enables to determine practical safety margins of spherical components containing a defect.

• 한국안전학회지
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• 제32권5호
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• pp.1-7
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• 2017

Forensic Engineering is the art and science of professionals qualified to serve as engineering experts in courts of law or in arbitration proceedings. Buses using compressed natural gas (CNG) trend to be extended in use internationally as optimal counterplan for reducing discharge gas of light oil due to high concern about environment. However, CNG buses is equipped with composite pressure vessels (CPVs); since the CPVs contain compressed natural gas, the risks in the case of accident is very high. In this study, the bursting test for the pressure vessel depending on the heat treatment conditions of the vessel in which the actual ruptured accident occurred, after the bursting test, the fracture pattern analysis had performed. The mechanical materials properties test using Instrumented Indentation Test had performed to confirm the mechanical properties for each heat treatment cases. Also, the fractography analysis and metallographic analysis had performed to find out the difference of each heat treatment case. By comparing normal vessel with abnormal vessel which have defect of heat treatment conditions in term of the bursting patterns and characteristics of containers using various forensic engineering methods, especially, it is possible to understand how important the heat treatment process is in the high pressure vessel unlike any product.

• Investigative Magnetic Resonance Imaging
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• 제11권1호
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• pp.49-53
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• 2007

섬유형성이상은 골모세포의 비정상적인 분화로 정상 골수와 해면골이 미숙골과 섬유성간질로 대치되는 유전이 되지 않는 골질환이다. 섬유형성이상은 다양한 영상소견을 보이며, 일반적으로 우연히 발견되며 정밀검사가 필요하지 않다. 그러나 섬유형성이상에서 병적골절의 합병증을 보일 수 있고 드물게 악성변이의 합병증을 가진다. 다골성섬유형성이상을 가진 44세 남자환자의 대퇴골에서 방사선소견상 골피질의 파괴와 자기공명영상에서 연부조직종괴를 가진 악성변이의 소견을 보였고, 수술로 절제된 조직학적 검사에서 연골아세포골육종으로 진단 받았다.

• Clinical and Experimental Pediatrics
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• 제46권10호
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• pp.1032-1035
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• 2003

저자들은 미숙아에서 이학적 검사상 AHO를 동반하지 않고, 생화학 검사에서는 저칼슘혈증, 고인산혈증, 혈청 PTH의 증가와 24시간 소변의 기저 cAMP의 증가를 보이면서, 대퇴골의 자발골절을 동반했던 가성부갑성선 기능저하증 1례를 문헌 고찰과 함께 보고하는 바이다.

• Journal of Welding and Joining
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• 제34권6호
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• pp.16-19
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• 2016

Needs for structural integrity procedure such as BS 7910, the nuclear industry document R6 Rev.4 and the European FITNET procedure are being increased in industry. Especially, BS 7910 allows metallic structures to be assessed on the basis of fracture mechanics analysis rather than strict adherence to design and fabricated codes. This study is to propose the flaw assessment to judge the toughness level of welding consumables at the development stage. The FCA welding consumables with YP 690MPa and CTOD over 0.25 mm have been developed and its allowable weld flaw size considering actually applied environment has been evaluated. Since the estimated allowable defect size is sufficiently detectable in nondestructive testing, the toughness of the developed material is judged to be appropriate and no problem in securing the structural integrity.