• The Korean Journal of Rheology
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• v.10 no.2
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• pp.98-105
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• 1998

가공공정중 변형을 수반하게 되는 고분자제품은 대부분 고분자사슬의 배향을 갖게 된다. 이렇나 사슬배향은 제품의 기계적, 광학적, 그리고 전기적 특성에 매우 중요한 영향을 미치는 것으로 알려져있다. 지금까지 고분자사슬의 배향상태를 나타내기 위한 여러방법은 모두 배향의 중심축을이 알려져 있다는 가정하에 전개되었다, 그러나 복잡한 배향모드를 갖 는 고분자가공의 경우에 배향중심측이 실험축과 일치하지 않는 경우가 많다 따라서 본연구 에서는 일반적인 고분자의배향상태를 나타내는 방법에 대해 알아보고 실제 고분자 가공공정 에 적용을 위해 실험적으로 배향의 대칭축을 찾을 수 있는 접근방법을 제시하고자 하였다. 그 결과 결정성 고분자의 배향상태를 광각 x-선 회절 data를 이용한2차배향 tensor를 통해 배향 타원체를 구성할수있었다. 이를PETdustls 필름과 HDPE사출성형물에 적용해 본 결과 이들의 2차 배향 tensor가 타원체를 잘 구성함을 알수 있었다. 또한 주어진 고분자의 결정 면들에 관계없이 고유한 중심축을 지니고 있음을 확인할수 있었다. 이를 통해 복잡한 배향 모드를 갖는 경우에 본연구에서 제안한 x-타원체를 통해 결정의 배향중심축을 효과적으로 찾을수 있음을 알수 있었다.

• Proceedings of the KAIS Fall Conference
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• 2010.11a
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• pp.301-304
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• 2010

본 논문에서는 다수 캐비티 금형의 러너 내 불균일한 전단분포로 인해 발생되는 충전불균형에 따른 치수정밀도, 기계적 강도 등 물성의 차이가 발생되는 문제점을 해소하기 위해서 수지가 처음 분기되는 2차 러너의 구조에 변화를 주어 다수 캐비티 사출성형에서 충전균형을 위한 러너시스템을 제시하였다. 이 러너시스템은 전단률차이에 의한 즉, 온도가 불균일한 수지의 흐름을 혼합함으로써 수지의 흐름을 균일하게 하여 충전균형을 이루도록 하였다. PP수지를 대상으로 각 캐비티 간 균형충전에 대해 이 러너시스템이 효과가 있는지 검증하기 위해 CAE프로그램(Moldflow)을 이용한 유동해석을 통해 그 효과를 나타내 보았다.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.367-372
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• 2000

By the means of microcellular (earning, we can make polymers with $10{\mu}m$ sized gas bubbles. After the $CO_2$ gas bubbles solve, diffuse and leave the polymer matrix, the thermal properties of polymer matrix are changed. Expecially, thermal conductivity becomes low. So, the polymer matrixes with gas bubbles can be used as insulator In this paper, we make model after microcellular foamed polymer matrix to know the change of thermal properties. Most of all, the purpose of this paper is the mlcrocellular foamed polymer matrix's availability as a insulator Beside of thermal properties the surface of microcellular foamed polymer is polished and easy to be colored. Above all the mechanical properties are better than the other insulator. So, microcellular foamed polymer can be used as exterior of building or it can be replaced as a tile.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1987.05a
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• pp.11.1-11
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• 1987

1984년 3월부터 1987년 2월까지 3년동안 canal wall dorm tympanoplasty를 시행한 환자 27 명을 관찰하여 다음 결과를 우선 얻을 수 있었다. 수술후 추적기간은 평균 4.6개월(1개월부터 1년 반까지)로 남자 18명, 여자 9명이었으며 평균 연령은 23.4세(7세부터 44세까지)이었다. 수술시 병명은 진주종성 중이염이 17례 (63%), intact canal tympanoplasty with recurrent or residual cholesteatoma가 4례(15%), 중이 근치 수술이 4례(15%)이었다. 수술 중 소견은 malleus (M), incus(I), stapes(S)의 전체 괴사가 11례 (41%), M·I 괴사와 수평반규관 노출이 각각 5례 (38%)씩 차지했다. 청력증진은 청력증진술을 1차에 시행한 18예 중, 추적 가능한 15례 중에서 5례 (30%)가 수술 후 8주이상의 청력검사결과 평균 31.4/10.4㏈를 나타냈다. 수술후 합병증으로 외이도 성형술을 동시에 시행한 20례중 경미한 육아조직 발생이 6예(30%) 외이도 성형술을 시행치 않은 7례 중 경미한 농성이루가 3례 (43%)로 나타났다.

• Journal of Digital Convergence
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• v.16 no.8
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• pp.401-411
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• 2018

The purpose of this study was to investigate appearance concern, attitude toward cosmetic surgery, self-esteem, quality of life, and to identify affecting factors of quality of life on elderly women. The subjects consisted of 162 elderly women in the G city. The variables were measured using questionnaires, analyzed using descriptive statistic, ${\chi}^2-test$, t-test, ANOVA, Pearson correlation coefficient, and multiple regression analysis. The appearance concern, attitude toward cosmetic surgery were not significant difference in 60s and 70s. Quality of life was significant difference in 60s and 70s. Factors influencing quality of life in 60s were self-esteem, perceived health status, and explanation of quality of life is 39.1%. In 70s were self-esteem, level of education, and explanation of quality of life is 41.7%. These results suggest that it is necessary for aging preparation education included appearance concern and should be made to develop program to improve quality of life.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.21 no.3
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• pp.270-276
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• 1999

저자등은 1996년 5월 부터 1999년 4월까지 인하대병원 치과에 악관절 질환을 주소로 내원한 958명의 환자 중 병력, 임상소견, 방사선학적 검사 결과 퇴행성 악관절 질환으로 진단된 68명에서 병록지 상에 기록된 환자의 성별, 나이, 주소, 병력, 현증상, 방사선학적 소견 및 치료방법 등에 관해 검사 후 다음과 같은 결론을 얻었다. 1. 남녀 발병 비율은 1:2로 여성에서 높았다. 2. 발병나이는 20대, 30대. 40대, 10대 순이었다. 3. 병력기간은 2년이상, 6개월이하, 1 - 2년 순이었다. 4. 전 환자에서 악관절 동통을, 44명의 환자에서 관절잡음을, 26명의 환자에서 개구제한을 호소하였다. 5. 그밖에 26명의 환자에서 관절부위에 민감성을, 5명의 환자에서 안면 비대칭을, 또한 개교합, 섬유성 악관절강직의 소견이 각각 2명의 환자에서, 양측성질환의 소견이 4명의 환자에서 관찰되었다. 6. 방사선학적 소견상, 15명 환자의 과두부에서 증식성 재성형소견(progressive remodeling)이, 51명의 환자에서 침식성 재성형소견(regressive or erosive remodeling)이 관찰되었으며, 침식성 재성형 환자 중 11명에서 과두주변부 증식성 재성형소견(peripheral remodeling or marginal lipping)이 관찰되었다. 7. 골증식체(osteophyte) 및 소성체(loose body)의 소견이 각각 2명의 환자에서 관찰되었다. 8. 약물에 의한 보존적 치료방법이 1차로 모든 환자에서 시행되었으며, 이중 12명의 환자는 교합안정장치를 병행하여 치료하였다. 9. 관절강내 스테로이드 주사요법에 의한 치료환자가 2명, 관절원판절제술 및 이개연골 이식술을 동반한 악관절성형술 환자가 각각 1명 및 2명이었다.

• Journal of Life Science
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• v.19 no.4
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• pp.486-491
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• 2009

This study was conducted to investigate microbial distribution in the processing steps and to estimate quality index and shelf life of packaged Tofu (soybean curd). Sanitation and safety of Tofu were analysed in aspects of total viable counts (TVCs) and coliforms. Organoleptic deterioration was observed from some packaged Tofu when their TVCs were over $10^6\;CFU/g$. The controlled simply packaged Tofu and sterilized Tofu with TVCs of under $10^5\;CFU/g$ were 32.0% and 86.9% of the total samples, respectively. Also, the controlled simply packaged Tofu and sterilized Tofu with negative coliforms were 12.0% and 83.7% of the total samples, respectively. TVCs and coliforms increased in some processing steps, which include washing and soaking of raw soybeans, and formation and 1st cooling of packaged Tofu. Increases of TVCs and coliforms in the washing and soaking step were due to contamination from the soaking tank and airborne bacteria, whereas increases of TVCs and coliforms in the grinding step were due to contaminations from the grinder, line and reserving tank. TVCs and coliforms increased in the formation and 1st cooling step of packaged Tofu due to contaminations from filter wools, trays, employee's hands, cooling water, formed products and filter wools.

• Restorative Dentistry and Endodontics
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• v.30 no.1
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• pp.58-65
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• 2005

The purpose of this study was to compare the shaping ability of the three $ProTaper^{(R)}$ instrumentation techniques in simulated canals. Thirty resin blocks were divided into 3 groups with 10 canals each. Each group was instrumented with manual $ProTaper^{(R)}$ (Group M), rotary $ProTaper^{(R)}$ (Group R), and hybrid technique (Group H). Canal preparation time was recorded. The images of pre- and post-instrumented root canals were scanned and superimposed. The amounts of canal deviation, total canal width, inner canal width, outer canal width and centering ratio were measured at apical 1, 2, 3, 4, 5 and 6 mm levels 1. Canal preparation time was the shortest in R group (p < 0.05). 2. The amounts of total canal width in R group was generally larger than the other groups, but no significant differences were observed except at the 1, 3 mm levels (p > 0.05) .3. The amounts of inner canal width in R group was larger than M group at the 1 mm level and H group was larger than R group at the 6 mm level (p < 0.05). The amounts of outer canal width in R group was larger than H group only at the 1 mm level (p < 0.05). 4. The direction of canal deviation in H, R group at the 1, 2, 3 mm levels was outward and that in M group at the 1, 2 mm levels was inward. The amounts of canal deviation in H group was larger than R group at the 6 mm level (p < 0.05). 5. The amounts of centering ratio in H group was larger than R group at the 6 mm level (p < 0.05).

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.2
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• pp.219-226
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• 2010

The stamping process is widely used in fabricating various sheet-parts for vehicle, airplane, and electronic devices due to its low processing cost and high productivity. Recently the use of thin sheets with corrugated structures has rapidly increased for the production of energy devices, e.g., heat exchangers and fuel cells. However, it is very difficult to make corrugated structures directly in the stamping process due to their geometrical complexity. To solve this problem, this paper proposes a multi-step stamping process with a combined heat treatment process: a sequence of the first stamping, heat treatment, and second stamping. By multi-stamping, we obtained successful results in fabricating very thin corrugated structures with thicknesses of $100{\mu}m$; these are applicable as part of a plate-type heat exchanger.

• Resources Recycling
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• v.12 no.6
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• pp.19-25
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• 2003

This experiment was carried out to examine the effect of iron oxide roasting for Sr-ferrite magnet. Chloride content was decreased with raising the 2 nd roasting temperature of iron oxide for ruthner process iron oxide. The optimization temperature for roasting of ruthner process iron oxide was around $800^{\circ}C$ as average particle size 1.5∼1.9 $\mu\textrm{m}$, apparent bulk density 1.4 g/$m\ell$ and chloride content 0.05%. The relation between Br and HcJ by sintering temperature for Sr-ferrite magnet was found to be Br≒-0.258HcJ＋494. In case of having a vibrating disk mill for the ruthner process iron oxide, the magnetic properties were Br 421 mT and HcJ 251 kA/m.