• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.6
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• pp.1903-1912
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• 1996

A quantitative study of impact damage of a soda-lime glass was carried out. An initiation and a propagation of cracks by the impact of two inds of steel ball was investigated. The fron, side and rear view of cracks were observed by a stereo-microscope. And the lowering of the benidng strength due to the impact of steel balls was examined through the 4-point bending test. A transparent glass is very helpful to understand and analyze the impact damage behavior of another brittle matereial. A deagdram about crack patterns according to the threshold impact velocity was sketched. A ring crack and a cone crack were formed at the low impact velocity. And as the impact velocity was higher, initial lateral crack was generated on the slanting surface of cone crack, and radial cracks were generated from the outermost ring crack. When the impact velocity of steel balls exceed a critical velocity, the contact site of specimens were crushed. According to the propagation of a cone crack, a rapid strength degradation occurred. In the specimen having crushed region, a bending strength was converged to a constant value instead of strength degradation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.7
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• pp.2196-2204
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• 1996

The damage mechanism by the impact of steel ball on the soda-lime glass having a different surface roughness was investigated. An initiation and a propagation behavior of cracks formed by each impact velocity were quantitatively studied. A 4-point bending test was carried out to evaluate the remaining bending strength of a scratched soda-lime glass which impacted by the steel ball. As the surface roughness was increased, the shape of cracks became more irregular rather than those of the smooth specimens. The phenomenon of turning up in the wing of cone cracks occurred even at the lower velocity than the critical velocity caused the crushing. The threshold velocity of cracks initiation generally became lower than those of smooth specimen. An initiation and a propagation behavior of radial cracks had no relation with the direction of scratch on the surface. The remaning benidng strength of the scratched specimen according to impact velocity had no big difference compared with those of the smooth specimen.

• Journal of Yeungnam Medical Science
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• v.13 no.2
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• pp.234-242
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• 1996

Ten patients with a thoracolumbar spine fractures were treated with Kaneda internal fixation device through anterolateral approach during last 1 year. In all cases, spinal decompression, internal instrument fixation and hone fusion with rib were performed. No patient showed neurological deterioration after surgery and 6(60%) patients improved postoperatively with entering the next Frankel subgroup. Follwo-up patient evaluation showed the correction of the fracture deformity with good bony fusion, but 3 patient arc remained back pain. According to above results we concluded that anterolateral internal fixation combined with hone fusion using rib was good mechanical stability and decompression of protruding ventral bone fragments above conus medullaris level.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.188-193
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• 2000

A more accurate life prediction for gas turbine blade takes into account the material behavior under the complex thermo-mechanical fatigue(TMF) cycles normally encountered in turbine operation. An experimental program has been carried out to address the thermo-mechanical fatigue life of the IN738LC nickel-base superalloy. In the first phase of the study, out-of-phase and in-phase TMF experiments have been performed on uncoated and coated materials. In the temperature range investigated. the deposition of NiCrAlY air plasma sprayed coating did not affect the fatigue resistance. In the second phase of the study, a physically-base life prediction model that takes into account of the contribution of different damage mechanisms has been applied. This model was able to reflect the temperature and strain rate dependences of isothermal cycling fatigue lives, and the strain-temperature history effect on the thermo-mechanical fatigue lives.

• Journal of the Korean Arthroscopy Society
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• v.7 no.1
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• pp.96-99
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• 2003

As arthroscopy is more advanced and the importance of meniscal function is more emphasized, there have been more advanced en meniscal repair technique. However conventional technique require the use of special instruments and extensive skin incision to protect the neurovasculatures and soft tissues. Also these have the potential problem of damage in articular surfaces by the knot. So, we develop a modified outside-in technique using spinal needles and nylon loops. Our method have many advantages not only in stability but simplicity, and there is no need of additional skin incision.

• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.246-251
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• 1999

This study was designed to evaluate the mutagenicity and the primary mutagenic mechanism of chloropropanols by using various genotypes of E. coli WP2, E. coli TK and E. coli GW series strains. Chloropropanols showed the low mutagenic activities in E. coli WP2s and WP2 establishing the following order; 2,3-DCP> 3-MCPD>1,3-DCP. As compared with E. coli WP2s, the decrease of mutagenic activity and the increase of survival rate in E. coli WP2 $(WP2s\;uvrA^+)$ suggest that DNA lesions produced by chloropropanols could be easily removed by excision-repair system. From the diminution of mutagenic activity and survival rate in E. coli CM611 (WP2s lexA), it was confirmed that the mutagenesis by chloropropanols was dependent on the SOS-repair system. This fact could be also confirmed from the result that both the mutagenic activity and survival rate in E. coli TK610 (umuC) were much lower than those in E. coli TK603 $(umuC^+)$. In the experiment to examine the possibility that chloropropanols might have effects on the LexA of SOS response negative regulator, there was no variation in ${\beta}-galactosidase$ activities of E. coli GW1105 $[lexA3\;(Ind^-)]$ and GW1107 [lexA51 (Def)] by addition of the compounds, indicating that chloropropanols do not have any effects on the LexA, itself.

• Journal of Korean Medical classics
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• v.19 no.3
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• pp.47-64
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• 2006

籬위제고화가심대청대정골추나요법적인식화이해(爲提高和加深對淸代正骨推拿寮法的認識和理解), 특선어차방면의의교심차유의사문환가치적(特選於此方面意義較深且有醫史文歡價値的) ${\ulcorner}$의종금감(醫宗金鑑) 정골심법요지(正骨心法要旨)${\lrcorner}$ 중적(中的) ${\ulcorner}$외치법(外治法)${\lrcorner}$ 진행료연구(進行了硏究), 획득여하연구결과(獲得如下硏究結果). 기수법총론부분(其手法總論部分), 파요지규정료정골수법적정의급기중요성(擺要地規定了正骨手法的定義及其重要性), 후유증적예방(後遺症的預防), 안환자원기강약이수요주의적사항(按患者元氣强弱而需要注意的事項), 정골의생적기본공화심이소질등문제(正骨醫生的基本功和心理素質等問題). 기정골수법부분(其正骨手法部分), 포괄모(包括模) 접(接) 단(端) 제(提) 접(按) 나(摩) 추(推) 나등팔법(拿等八法), 각법지적응증용현대용어해석여하(各法之適應症用現代用語解釋如下): 모법용어촉진(模法用於觸診), 접법용어골절치료(接法用於骨折治療), 단법용어탈위치료(端法用於脫位治療), 제법용어견인법(提法用於牽引法), 안마법용어연조직손상화골착건적치료(按摩法用於軟組織損傷和骨錯鍵的治療), 추나법용어절적운동(推拿法用於節的運動) 부리화관절적부완전결합적치료(不利和關節的不完全結合的治療). 기기구총론부분(其器具總論部分), 개소료십종정골치료용기구(介紹了十種正骨治療用器具), 각종기구적적응증급기효능용현대용어해석여하(各種器具的適應症及其效能用現代用語解釋如下): 이렴구유보호환부적효과(裏簾具有保護患部的效果), 진정용어동통(振挺用於疼痛) 부종(浮鍾) 경결적치료(硬結的治療), 피견용어견관절탈구적고정료법(被肩用於肩關節脫臼的固定療法), 격색속어리용자아체중적견인료법(擊索屬於利用自我體重的牽引療法), 루관속어분부동계단이용자아체중진행견인적료법(壘觀屬於分不同階段利用自我體重進行牽引的療法), 통목속어포추지압축성골절적래목치료용구(通木屬於胞推之壓縮性骨折的來木治療用具), 요주구유대요추골급기근육이상적부가보호대효과(腰柱具有對腰推骨及其筋肉異常的附加保護帶效果), 죽렴용어골절적고정치료(竹簾用於骨折的固定治療), 삼리구유대골절적쌍중고정효과(杉籬具有對骨折的雙重固定效果), 포슬구유대슬관절적고정효과(抱膝具有對膝關節的固定效果).

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.3
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• pp.251-260
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• 2001

Damage Profess of CFRP laminates under monotonic tensile test was characterized by the correlation between Acoustic Emission(AE) and Ultrasonic Test(UT). The amplitude distribution of AE signal from a specimens is an aid to the determination of the extent of the different fracture mechanism such as matrix crack, debonding, fiber pullout and fiber fracture as load is increased. In addtion, the characteristics of ultrasonic amplitude attenuation are useful lot analysis of the different type of fracture mechanism. Different orientation of carbon fiber reinforced plastic specimens were used to investigate the AE amplitude range and ultrasonic amplitude attenuation. Finally, loading-unloading tests were carried out to check Felicity effect. During the tests, ultrasonic amplitude attenuation was investigated at the same time and compared with AE parameters. The result showed that two parameters of both AE and UT could be effectively used for analysis of fracture mechanism in CFRP laminates.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.3
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• pp.267-272
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• 2012

Dental professionals are exposed to various occupational risks, among which the problem of hearing damage has been newly revealed. There have been some researches reporting that noise occurring in a dental office exceeds the Occupational Safety and Health Act (OSHA) Standards. Especially, the pediatric dentists are repeatedly exposed to an additional noise source called the crying sound of children in addition to all kinds of noises from dental instruments. Accordingly, this study intended to investigate the noise environment likely to affect pediatric dentists and to examine the possibility of resultant hearing damages. The level of noise was measured respectively, when various dental instruments (ultrasonic scaler, high-speed handpiece, low-speed handpiece) are operated, when children are crying, and when both occasions take place simultaneously (from the distance of 30 cm) with a portable noise meter. And the daily duration of pediatric dentists exposed to the noise environment was surveyed. The results were compared with the standard value of noise threshold of NIOSH, OSHA, and that of hearing damage of CRA News letter respectively. Considering the intensity and exposure time, the noise environment of pediatric dentists exceeds the allowable noise threshold values. Even only one exposure to crying child was likely to lead to permanent hearing damage. Comparatively, pediatric dentists have a higher risk for occupational hearing damages, and some active measures are thought highly desirable to minimize it.

• Korean Journal of Food Science and Technology
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• v.20 no.3
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• pp.287-292
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• 1988

The inhibition mechanism of DNA damage by lipid peroxidation was studied through the reaction systems of plasmid pBR322 DNA, linoleic acid and the ethanol extracts obtained from ginger and garlic. The DNA damage was greatly inhibited by the addition of ginger and garlic extracts, and their scavenging effects of active oxygens were also great. It is considered that the inhibitory effects of these extracts on the DNA damage are mainly due to their scavenging effects of active oxygen radicals.