• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2005년도 춘계학술대회 논문집
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• pp.209-215
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• 2005

The dimensions and forms of precise machined parts are different to kinds of machine. It will be variant according to machine wear, tool form, cutting method and cutting condition at the same machine. At that time, the most important things are controlled and measured by appropriate measuring instruments. This paper aims to contribute to improving measurement accuracy through evaluation and consideration about various roundness in the machining company.

• 대한의용생체공학회:의공학회지
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• 제44권2호
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• pp.109-117
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• 2023

In this study, the effect of the shape of the specimen and the feedrate of the dental ultrasonic surgical instrument on the cutting force and surface roughness of the specimen is analyzed. Experimental specimens were made of SAWBONES artificial bone materials in square and spherical specimens. In addition, the cutting feedrate of the surgical instrument was controlled through the developed moving system. The cutting force generated when cutting the specimen was measured through a force sensor. After the experiment, the cutting surface of the specimen was observed through a three-dimensional optical microscope and the surface roughness was measured. Through one-way ANOVA, the effect of each specimen shape and feed rate on surface roughness was analyzed. As a result of the experiment, the cutting force increased proportionally in the initial feed rate increase stage, but the increase in cutting force decreased as the feed rate continued to increase. Also, the cutting force showed a difference according to the shape of the specimen. The spherical specimen with a relatively small cutting surface area had less cutting force than the square specimen. However, as a result of one-way ANOVA, it was found that the specimen shape and feed rate did not affect the surface roughness. In future studies, it is expected to be used for comparative analysis of ultrasonic surgical instruments and correlation analysis between cutting factors.

• Journal of Periodontal and Implant Science
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• 제27권3호
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• pp.575-584
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• 1997

The quality of periodontal instrument cutting edge is a basic element of effective root planing procedure. Using instruments, the sharp edge is changed into blunt or beveled edge. With the blunt instrument, the periodontal treatment can't be carried into accuracy and effective. The study on the wear of periodontal curet is insufficient, there are few publications about the change of sharpness of cutting egde after using instrument and a certen reports were published on the study of scanning electron microscope(SEM) examination. In this study, to declare the number of strokes for sharpening of instruments, the changes of cutting edge is measured by the clinical methods, tactile sensitivity examination and refraction light-white line test after scaling strokes and root planing strokes. SEM test was added for defined the changes of cutting edges. The 7/8 Gracey curets that have been never used was tested. Maxillary molars which were extracted from the School of Dental Medicine, Dankook University was used. Subjected teeth had attachment loss more than 6 mm in bucca-lingual surface and sufficient calculus of a band type in cervical area. The strokes of curet were executed 3, 5, 7, 9, 11, 13 times on scaling stroke and 10, 15, 20, 25, 30, 35 times on root planing stroke. A resident has periodontal experience over 3 years carried out the clinical examinations those tactile sensitivity examination and refraction light-white line test 5 times. The case there being tactile sensitivity certenly is 2, the case being felt tactile sensitivity is 1, and the case there not being tactile sensitivity is 0. The visual examination was recorded as following. The case that refracted white line is not recognised is 2, the case that uncerten is 1, and the case that acknowledged is 0. The results were obtained as follows. 1. After scaling strokes, the tactile sensitivity was reduced after 11 strokes and disappeared in 13 strokes. 2. In tactile sensitivity after root planing procedures, sensitivity was reduced after 25 strokes and disappeared in 35 strokes. 3. In case of visual examination, the detection of refracted white line was increased after 9 strokes of scaling procedures and the accuracy of wear wasn't showed after root planing procedures. 4. In SEM, metal projection was observed on new periodontal curet cutting edge and it was disappeared after scaling procedures. 5. In SEM, the cutting edge was showed changing linear into an aspect of the surface after 5 strokes of scaling procedures and 10 strokes of root planing procedures and showed beveled edge in 11 strokes of scaling procedures, 25 strokes of root planing procedures. The results of 3-type examination indicated that the sharpening of curet should be performed after 11 strokes of scaling procedures and 25 strokes of root planing procedures.

• Restorative Dentistry and Endodontics
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• 제23권1호
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• pp.54-67
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• 1998

치근단 역충전 와동 형성을 위한 초음파 다이아몬드 기구의 임상적 적용의 타당성 및 특성을 평가하기 위해, 다이아몬드 기구의 상아질 삭제능력, 역충전 외동 형성효율 및 치질에 미치는 영향을 관찰하여 스테인레스 스틸 기구와 비교, 평가하였다. 치근단 역충전 와동 형성시 다이아몬드 기구와 스테인레스 스틸 기구를 발거된 소의 치아에서 노출시킨 상아질 표변에 일정한 출력과 시간 조건 하에서 작동시켜 상아질 표면으로부터의 삭제된 깊이를 측정하였다. 역충전 와동 형성효율을 평가하기 위하여 발거된 상악 제 1 대구치 치근에서 근관을 형성하고 gutta-percha로 충전한 다음 근단 3mm부위를 치아 장축에 직각되게 절제하고 초음파 기구의 와동형성 소요 시간 및 소요 stroke 수를 측정하였다. 초음파 기구를 이용한 와동 형성이 치질에 미치는 영향을 평가하기 위하여 초음파 와동 형성 전후의 치근단부 치질의 균열 발생빈도를 측정, 평가하여 다음과 같은 결과를 얻었다. $\cdot$ 저출력 또는 중출력에서 그리고 노출된 상아질에 수직 또는 수평으로 기구를 적용한 경우 모두에서, 다이아몬드 기구가 스테인레스 스틸 기구에 비해 높은 상아질 삭제효과를 나타내었다(p<0.01). $\cdot$ 초음파기구를 상아질 표면에 수직으로 적용한 경우에 출력이 높을수록 상아질 삭제효과가 우수하였으며, 수평으로 적용한 경우에는 출력에 따른 유의한 증가가 나타나지 않았다(p<0.01). $\cdot$ 중출력에서는 다이아몬드 기구가 스테인레스 스틸 기구에 비해 와동형시 소요되는 stroke 수와 시간으로 본 와동형성효율이 유의하게 우수하게 나타났다(p<0.05). $\cdot$ 저출력에서는 다이아몬드 기구가 스테인레스 스틸 기구에 비해 외동형성 후 치근단 균열 발생빈도가 유의하게 적게 나타났다(p<0.01).

• Clinical Endoscopy
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• 제51권6호
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• pp.552-557
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• 2018

Although colonoscopy was originally a diagnostic imaging procedure, it has now expanded to include an increasing range of therapeutic interventions. These procedures require precise maneuvers of instruments, execution of force, efficient transmission of force from the operator to the point of application, and sufficient dexterity in the mobilization of endoscopic surgical instruments. The conventional endoscope is not designed to support technically demanding endoscopic procedures. In case of colonoscopy, the tortuous anatomy of the colon makes inserting, moving, and orientating the endoscope difficult. Exerting excessive pressure can cause looping of the endoscope, pain to the patient, and even perforation of the colon. To mitigate the technical constraints, numerous technically enhanced systems have been developed to enable better control of instruments and precise delivery of force in the execution of surgical tasks such as apposing, grasping, traction, counter-traction, and cutting of tissues. Among the recent developments are highly dexterous robotic master and slave systems, computer-assisted or robotically enhanced conventional endoscopes, and autonomously driven locomotion devices that can effortlessly traverse the colon. Developments in endoscopic instrumentations have overcome technical barriers and opened new horizons for further advancements in therapeutic interventions. This review describes examples of some of these systems in the context of their applications to advanced therapeutic colonoscopy.

• 대한환경공학회지
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• 제35권6호
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• pp.394-399
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• 2013

가정 하수구의 주요 오물은 난분해성 모발로서 이것이 하수의 악취를 막기 위한 유트랩 장치에 다량으로 쌓이게 된다. 이러한 오물은 물의 흐름을 막는 현상을 일으키기 때문에 대부분의 가정에서 이를 해결하기 위해 상업적으로 제조된 화학적 분해 용액을 하수구에 과량 투입하여 하수구의 막힘 현상을 해결하고 있다. 본 연구에서는 난분해성 케로틴 단백질이 주성분인 모발을 절단 분쇄하는 장치를 개발하여 실험하였다. 실험을 위하여 모발을 효과적으로 절단할 수 있는 절단 분쇄장치를 설계하였으며 그 절단 성능을 실험적인 방법을 통해 규명하였다. 모발 절단 분쇄 장치의 성능을 평가하기 위하여 섬유다발을 부분 절단한 후 무게를 측정하는 방법을 사용하여 절단 모발의 평균길이를 구하였다. 이 방법은 비교적 간단한 무게 측정 방법을 통해 섬유상의 평균 길이를 구하는 것인데, 이를 모발에 적용하여 평균 모발 길이를 크지 않은 오차 범위에서 구할 수 있었다. 또한, 평균절단수를 정의하여 본 연구를 위해 고안된 모발 절단 분쇄 장치의 성능을 평가하였다. 평균절단수 분석 방법을 적용하여 주어진 실험 조건에서 최적의 구조와 최적의 작동시간을 구하는 기준을 제시할 수 있었다. 이러한 실험 방법과 결과는 섬유형태 물질의 절단 분쇄가 필요한 다른 장치에서도 설계와 분석에 사용할 수 있는 하나의 좋은 예시가 될 것이다. 본 연구에서 고안된 절단 분쇄 장치가 실험을 통하여 효과적으로 모발을 절단 분쇄하는 것을 확인할 수 있었다. 이러한 장치를 일반 가정에 설치하여 보급함으로써 최근 심각해지고 있는 하수구에 의한 수질환경 오염 방지에도 효과적인 도움이 될 것이다.

• Restorative Dentistry and Endodontics
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• 제32권4호
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• pp.327-334
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• 2007

이 연구는 서로 다른 카바이드 버와 다이아몬드 버로 5급 와동을 형성 한 후 SE primer 접착 시스템인 Clearfil SE Bond를 이용한 복합레진 수복 시 버의 종류에 따른 법랑질과 상아질 변연에서의 미세누출 차이를 상호 비교하기 위하여 시행하였다. 4종의 삭제기구를 이용하여 각각 10개의 발거된 대구치의 협면 치경부에 5급 와동을 형성하였다. 1군은 plain-cut carbide fissure bur (no. 245)를 사용한 군, 2군은 cross-cut carbide fissure bur (no. 557)를 사용한 군, 3군은 fine diamond bur (TF-21F: 입자크기 $53\;-\;63\;{\mu}m$)를 사용한 군, 4군은 standard diamond bur (EX-41: 입자크기 $106\;-\;205\;{\mu}m$)를 사용한 군으로 분류하였다. 형성된 와동에 Clearfil SE Bond의 Primer와 Bond를 적용하고 Clearfil AP-X 복합레진을 충전하여 광중합한 후, Sof-Lex disc를 이용하여 마무리와 연마를 시행하였다. 수복된 치아를 2% methylene blue 용액에 24시간 동안 침적시킨 후 각 군의 치아를 협설로 절단하여 광학 입체현미경 하에서 법랑질과 상아질 변연에서의 미세누출 점수를 평가하여 다음과 같은 결과를 얻었다. Clearfil SE Bond와 복합레진을 이용한 5급 와동 수복 시 거친 다이아몬드 버의 사용은 카바이드 버나 미세한 다이아몬드 버에 비해 법랑질과 상아질 변연 모두에서 높은 미세누출을 나타내었다.

• Restorative Dentistry and Endodontics
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• 제41권3호
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• pp.176-181
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• 2016

Objectives: This study aimed to compare two nickel-titanium systems (rotary vs. reciprocating) for their acceptance by undergraduate students who experienced nickel-titanium (NiTi) instruments for the first time. Materials and Methods: Eighty-one sophomore dental students were first taught on manual root canal preparation with stainless-steel files. After that, they were instructed on the use of ProTaper Universal system (PTU, Dentsply Maillefer), then the WaveOne (WO, Dentsply Maillefer). They practiced with each system on 2 extracted molars, before using those files to shape the buccal or mesial canals of additional first molars. A questionnaire was completed after using each file system, seeking students' perception about 'Ease of use', 'Flexibility', 'Cutting-efficiency', 'Screwing-effect', 'Feeling-safety', and 'Instrumentation-time' of the NiTi files, relative to stainless-steel instrumentation, on a 5-point Likert-type scale. They were also requested to indicate their preference between the two systems. Data was compared between groups using t-test, and with Chi-square test for correlation of each perception value with the preferred choice (p = 0.05). Results: Among the 81 students, 55 indicated their preferred file system as WO and 22 as PTU. All scores were greater than 4 (better) for both systems, compared with stainless-steel files, except for 'Screwing-effect' for PTU. The scores for WO in the categories of 'Flexibility', 'Screwing-effect', and 'Feeling-safety' were significantly higher scores than those of PTU. A significant association between the 'Screwing-effect' and students' preference for WO was observed. Conclusions: Novice operators preferred nickel-titanium instruments to stainless-steel, and majority of them opted for reciprocating file instead of continuous rotating system.

• 지역사회간호학회지
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• 제22권3호
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• pp.302-314
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• 2011

Purpose: This study aimed to validate instruments to classify the frailty of Korean elderly people in community. Methods: For this study, 632 elders were selected from community-based elderly houses and home visiting registries, and data on frailty were collected using three instruments during November, 2008. The Korean Frail Scale (KFS) was composed of 10 domains with the maximum score of 20. The Edmonton Frail Scale (EFS) had 10 domains with the maximum score of 17. The 25_Japan Frail Scale (25_JFS) was composed of 6 domains with the maximum score of 25. Internal consistency was measured with Cronbach's ${\alpha}$. Sensitivity, specificity and area under the curve (AUC) of ROC were measured to see validity with long.term care insurance grade as a gold standard. Results: The Cronbach's ${\alpha}$ was .72 for KFS, .55 for EFS, and .80 for 25_JFS. Sensitivity, specificity, and AUC were 70.0%, 83.2%, and .83, respectively, at cutting point 10.5 for the KFS, 50.0%, 80.9%, and .66, respectively, at 8.5 for EFS, and 80.0%, 85.9%, and .86, respectively, at 12.5 for 25_JFS. Conclusion: KFS and three JFS showed favorable internal consistency and predictive validity. Further longitudinal studies are recommended to confirm predictive validity.

• 여성건강간호학회지
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• 제4권1호
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• pp.123-138
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• 1998

The purpose of this study was to describe perimenstrual symptom severity levels and perimenstrual distress patterns of women. The study performed the discriminant analysis in which included seven factors : age, pariety, social support, menstrual socialization(mother's symptom, sister's symptom, and menstrual effect), attitude of sex role and depression. The subjects were 283 women that they were not pregnant or lactating, had at least one period in past three months, would understand the purpose of study and willingly accepted the participation. The data analysis was done by pc-SAS program after data collection from Nov. 20, 1997 to Dec. 18, 1997. The descriptive analysis was done to explore general characteristics of the subjects and the stepwise discriminant analysis was done to verify factors in relation to perimenstrual symptom severity levels(severe vs mild menstrual symptom group) and perimenstrual distress patterns(spasmodic vs congestive menstrual symptom group). The instruments were selected for this study from Interpersonal Support Evaluation List(ISEL) by Cohen and Hoberman(1983), Center for Epidemic Studies Depression(CES-D) by Radloff(1977), and Sex Role Attitude Scale by Yunok Suh(1995), Mother's symptom and sister's symptom measurements by Woods, Mitchell & Lentz(1995), and menstrual effect by Brooks-Gun & Ruble(1980). The major findings of this study are as follows : 1. Of the 283 women, 93 women(32.9%) were assessed to severe perimenstrual symptom group and 190 women(67.1%) were assessed to mild perimenstrual symptom group. Results from the stepwise discriminant analysis showed three factors, such as depression, menstrual effect, and age, significantly related to perimenstrual symptom severity and they explained 20% of the total variance. The linear discriminant equation included three factors related to perimenstrual symptom groups was showed(Z=1.445 depression+0.174 menstrual effect-0.054 age). The cutting score(Z) was 2.809. We classified the severe perimenstrual symptom group by more than the cutting score 2.809 and the mild perimenstrual symptom by less or equal than the cutting score 2.809. The correctedness of posterior probability from discriminant equation was 72% as two perimenstrual symptom group classifications. 2. Of the 264 women, 139 women(52.7%) were assessed to spasmodic perimenstrual distress group and women(47.3%) were assessed to congestive perimenstrual distress group. Results from the stepwise discriminant analysis showed two factors, such as depression, age, significantly related to perimenstrual distress groups and they explained 8% of the total variance. The linear discriminant equation included two factors related to perimenstrual distress group was showed(Z=-0.084 age-0.776 depression). The cutting score(Z) was -3.759. We classified the spasmodic perimenstrual distress group by more than cutting score -3.759 and the congestive perimenstrual distress group by less or equal than cutting score -3.759. The correctedness of posterior probability from discriminant equation was 65% as two perimenstrual distress group classifications.