• 마이크로전자및패키징학회지
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• 제18권2호
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• pp.57-62
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• 2011

염료 감응 태양 전지(Dye-Sensitized Solar Cells: DSSCs)의 에너지 변환효율은 $TiO_2$ 전극의 입자 크기, 구조 및 표면 형태에 의존한다. 높은 비표면적을 갖는 나노 크기의 아나타제 $TiO_2$는 많은 염료를 흡착할 수 있어 변환효율을 증가 시킨다. 또한 전극 내부에서 태양광의 산란을 증가 시키면, 염료가 태양광을 흡수하는 양이 증가하여 효율이 증가할 수 있다. 수열 합성법으로 합성한 $TiO_2$ 분말의 크기는 15-25 nm이고, 결정상은 구형의 anatase 상이다. 0.4 ${\mu}m$의 $TiO_2$ 산란입자를 합성한 나노 크기의 $TiO_2$ 분말에 혼합하여 전극을 제조하고, DSSCs를 제작한 후 변환효율을 측정하였다. 10% 의 산란 입자가 포함된 DSSCs는 단락전류 3.51 mA, 개방전압 0.79 V, 곡선인자 0.619로 6.86%의 변환 효율을 나타 내었다. 산란 입자의 영향으로 단락전류밀도는 11% 증가하였고, 효율은 0.77% 증가하였다. 산란 입자가 포함되지 않은 DSSCs 보다 산란 입자가 전극으로 들어온 태양광을 산란시켜 전자-홀 쌍의 생성을 증가 시키고, 전자가 전극을 따라 이동하는 경로가 감소하여 효율이 증가하였다. 10% 이상의 산란 입자는 전극 내부에 입자 크기의 큰 기공을 증가 시켜 효율이 감소하였다.

• 대한소아치과학회지
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• 제45권2호
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• pp.162-169
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• 2018

본 연구의 목적은 새로운 비색법인 $Cariview^{(R)}$를 이용한 우식 활성 검사의 타당성 및 모자간 우식 경험 및 활성의 상관성 평가를 하고 기존의 특정 세균 배양법인 $CRT^{(R)}$ bacteria 검사와 비교 평가하는 것이다. 만 6세 미만 어린이 - 어머니 34쌍(총 68명)이 사전 동의 하에 연구에 참여하였다. 설문 조사 및 구강 검사 후 우식 활성 검사인 $Cariview^{(R)}$와 $CRT^{(R)}$ bacteria 검사를 각각의 대상자에게 시행하였다. 실험 결과 $Cariview^{(R)}$ 점수는 어린이의 우식 경험 유치수(dft)와 통계적으로 유의한 상관성을 나타냈고(r = 0.598, p < 0.01) 상관 정도는 $CRT^{(R)}$ bacteria 점수보다 높았다. $Cariview^{(R)}$ 점수는 어머니와 어린이의 우식 치아수(DT, dt)와 통계적으로 유의한 상관성을 나타냈다(p < 0.05). $Cariview^{(R)}$와 $CRT^{(R)}$ bacteria 검사 모두에서 모자간 우식 경험 및 우식 활성은 통계적으로 유의한 상관성을 나타내지 않았다(p > 0.05). $Cariview^{(R)}$ 비색법은 어린이의 치아 우식 경험 및 현재의 치아 우식 상태를 적절히 반영하며 우식 위험도를 예측하고 예방 전략을 수립하는 데 임상적으로 유용할 것으로 판단된다.

• 콘크리트학회논문집
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• 제29권3호
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• pp.259-266
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• 2017

본 연구는 PHC말뚝의 단점인 전단력을 보강한 기능성말뚝을 개발하여 보다 경제적이고 합리적인 말뚝의 현장 적용에 기여하고자 하였다. 본 연구를 통해 개발된 CFP말뚝은 링형 합성 전단연결재를 배치하고 PHC말뚝 중공부에 콘크리트를 속채움함으로써 말뚝의 전단성능을 증대시키고, PHC말뚝 내 보강철근(H13-8ea)과 말뚝 중공부의 보강철근(H19-8ea)을 배치하여 횡보강철근비 증대에 따른 전단강도를 향상시켰다. 또한, 속채움 콘크리트와 PHC말뚝의 합성거동을 위해 말뚝 보강철근의 정착 홀이 형성된 합성 전단연결재를 배치하여 보강철근의 다월력을 말뚝의 전단강도 증진에 효과적으로 반영시켰다. CFP말뚝의 전단설계와 성능을 검증하고자 도로교설계기준의 한계상태설계법(2012)을 적용한 전단강도를 산출하였고, 말뚝 시험규정인 KS F 4306에서 제시한 실험방법을 통해 결과값을 비교 검토하였다. CFP말뚝의 단면별 설계전단강도와 실험결과 각 시험체는 설계전단강도 대비 평균 2.20, 2.15, 2.05의 안전율을 확보하는 것으로 나타나 효과적인 전단강도 예측이 가능할 것으로 생각된다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제27권1호
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• pp.15-24
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• 2001

The purpose of this study is to evaluate the tissue response in applying of various bone substitutes included toothash-plaster mixture, resorbable hydroxylapatite (HA) and demineralized freeze-dried bone and to show the clinical usefulness of toothash-plaster mixture for the repair of craniomaxillofacial bone defect. For this experiment, 100 Sprague-Dawley rats weighing 200gm or more were used. There were four experimental groups: group I, toothash-plaster mixture; group II, demineralized freeze-dried bone; group III, resorbable HA; and group IV, control group. A full thickness, round bone defect measuring 10mm in diameter was created in the midcranium, and the substitutes cited above were embedded in the experimental rats based on their group assignment. Blood clot was filled in the rats assigned to the control group. Experimental rats were sacrificed on the 1st, 3rd, 5th, 8th, 12th and 24th week after implantation and stained with the hematoxylineosin, Masson's Trichrome, using Van Gieson's stain method, and were examined under light microscope. The results were as follows: 1. In all the groups, prominent inflammatory reaction and the infiltration of multinucleated giant cells were noted during the early stage. Gradual healing decreased this reaction. 2. Among the rats in the experimental group II, which were given demineralized freeze-dried bone implants, active formation of new bone traveculae manifested. Chondroid tissues appeared, and it was suggested that the defect was filled with newly formed bone by virtue of osteoinductive activity. On the 12th week after the experiments, most of the defect was filled with newly formed bone trabeculae. 3. In experimental groups I and III, it was noted that HA manifested a healing process similar to that characterized by the toothash-plaster mixture, but inflammatory reaction was more prominent in experimental group I. Active osteoblasts were observed along the periphery of osteoid tissues, while newly formed bone trabeculae appeared adjacent to the implanted materials three weeks later. Formation increased to the extent that newly formed bone trabeculae fused directly with the host bone. Increase in new bone ingrowth into the filling materials was revealed by both experimental groups. 4. In the control group, new bone formation adjacent to the host bone was observed, but most of the defect was filled with mature connective tissue 24 weeks after the experiments.

• 치과방사선
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• 제28권2호
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• pp.471-489
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• 1998

For the successful endodontic treatment, root canal should be cleaned thoroughly by accurate mechanical and chemical canal preparation and sealed completely with canal filling material without damaging the periapical tissues. The accuracy of the root canal length measurement is a prerequisite for the success of the endodontic treatment, and the root canal length is often determined by the standard periapical radiographs and digital tactile sense. In this study, the accuracy and the clinical usefulness of Digora/sup (R)/, an intraoral digital imaging processor and the conventional standard radiographs were compared by measuring the length from the top of the file to the root apex. 30 single rooted premolars were invested in a uniformly sized blocks and No.25 K-file was inserted into and fixed in each canal. Each block was placed in equal distance and position to satisfy the principle of the bisecting angle and paralleling techniques and Digora/sup (R)/ system's image and standard periapical radiographs were taken. Each radiograph was examined by 3 different observers by measuring the length from top of the file to the root apex and each data was compared and analyzed. The results were as follows; 1. In the bisecting angle technique, the average difference between the Digora/sup (R)/ system and standard periapical radiograph was 0.002 mm and the standard deviation was 0.341 mm which showed no statistically significant difference between the two systems(p>0.05). Also, in the paralleling technique, the average difference between these two system was 0.007 mm and the standard deviation was 0.323 mm which showed no statistically significant difference between the two systems(p>0.05). 2. In Digora/sup (R)/ system, the average difference between the bisecting angle and paralleling technique was -0.336 mm and the standard deviation was 0.472 mm which showed a statistically significant difference between the two techniques(p<0.05). Also, in the standard periapical radiographs, the average difference between the bisecting angle and paralleling technique was 0.328 mm and the standard deviation was 0.517 mm which showed a statistically significant difference between these two techniques(p<0.05). 3. In Digora/sup (R)/ system and the standard periapical radiographs. there was a statistically significant difference between the measurement using the bisecting angle technique and the actual length(p<0.05), But there was no statistically significant difference between the measurement using the paralleling technique and the actuallength(p>0.05). In conclusion. the determination of the root canal length by using the Digora/sup (R)/ system can give us as good an image as the standard periapical radiograph and using the paralleling technique instead of the bisecting angle technique can give a measurement closer to the actual canal length. thereby contributing to a successful result. Also. considering the advantages of the digital imaging processor such as decreasing the amount of exposure to the patient. immediate use of the image. magnification of image size. control of the contrast and brightness and the ability of storing the image can give us good reason to replace the standard periapical radiographs.

• 대한치과보철학회지
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• 제44권5호
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• pp.654-664
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• 2006

Statement of problem: There has been a eat interest in the use of titanium for fixed and removable prostheses in recent because of its excellent biocompatibility. However, the melting temperature and chemical reactivity of titanium necessities casting system different from those used in conventional casting. The current titanium casting systems are based on an electric-arc design for melting the metal in an argon atmosphere and its exclusive investment. Despite the new development in Ti casting system, inadequate mold filling and internal porosity are frequently observed casting defects. Purpose : The purposes of this study were to compare the castibility and reaction layer of the casting titanium under the two casting machines and their investment condition. Material and method: coping and machine-milled titanium coping according to the casting methods and the marginal configurations. The total 28 specimens were used, and these are divided into 4 groups according to 2 casting machines and 2 investments. The castings were analyzed using x-ray microanalysis and microhardness testing. The reaction layer between margin of titanium casting and the investments was observed and analyzed with scanning electron microscope. Result: 1. Castabiliy of casting titanium specimen was best in the group of centrifugal casting machine and Selevest $CB^{\circledR}$ and good that of Selevest CB and pressure differential casting machine, Rematitan plus and centrifugal casting machine, Rematitan plus and pressure differential casting machine in order. 2. There was no significanct correlation in titanium castability in respect of casting machine. However ANOVA indicated that Selevest $CB^{\circledR}$ groups had significantly better castability than Rematitan $plus^{\circledR}$ groups.(p<0.05) 3. There was a significant microhardness difference between centrifugal casting machine groups and pressure differential groups.(p<0.05) Titanium castings in centifugal groups had significantly harder than those in pressure differential groups. 4. The addition of zirconia decreased interfacial reactivity. Conclusion: above result revealed that of the castability of titanium casting specimens had little correlation in casting machines and was better in magnesia-based investment contained ZrO2 groups. However in order to practice casting titanium in clininic, its castability should be improved, also there should be more research on factor of castability so that long-span prothesis and removable partial denture metla frame may be casted completly.

• Tuberculosis and Respiratory Diseases
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• 제46권5호
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• pp.709-717
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• 1999

연구배경 및 방법 : BOOP는 미만성 간질성 폐질환의 일종으로 기질화폐렴의 특별한 한 형태로도 구분되는 아주 특별한 임상병리 소견을 가진 질환이다. 임상적으로는 내원 수주전부터 감기 유사증상을 앓다가 점차 악화되는 호흡곤란 증세로 내원하여 마치 폐렴양 소견을 보이며, 병리학적으로 폴립형의 육아 조직이 세기관지내에 충전되어 관강내 용종양 조직을 형성하고 폐포관에까지 침범된 기질화된 폐렴의 소견을 보인다. 최근, 저자등은 본원에서 경험한 다섯 증례와 국내의 학술지상에 증례 보고된 19예를 합하여 그 임상적 특성에 대해 분석해 보고 국외의 문헌보고 결과들과 비교분석하고자 하였다. 결 과 : 국내 환자들의 평균연령은 54세이었으며 여성에서 약간 더 많이 발생하였다. 병원에 내원한 주증상은 호흡 곤란 및 기침이었으며 그 지속기간은 평균 41일이었다. 흉부진찰에서 흡기시 악설음이 흔히 관찰되었고 여러 혈액학적 검사소견은 저산소혈증외에는 비특이적이었으며 이들 소견만으로는 폐렴과 구분하기 어려웠다. 폐활량검사에서는 제한성 혹은 폐쇄성과의 혼재형 환기장애가 주소견이었으며 방사선학적으로는 양측성, 반상의 비엽성 폐포침윤을 보였고 고해상 컴퓨터단층촬영에서 잘 확인되었다. 다른 간질성폐질환과는 달리 부신피질호르몬의 치료에 잘 반응하여 양호한 예후 및 경과를 보였다. 상기 국내의 결과는 국외 문헌보고에서 얻은 결과와 비교시에 대체적으로 유사 소견을 보였으나 국내는 여자에서 더 흔히 발생한 차이가 있었으며 엑스선 소견 및 임상경과 등에 대해서는 좀더 추적조사를 하여 비교해야 할 것으로 판단된다. 결 론 : 폐렴양 소견을 보이는 환자에서 적절한 치료에도 불구하고 임상양상이 비전형적이고 진행시에는 임상소견 및 방사선학적 소견 등을 BOOP의 관점에서 재점검해야 할 것이다. 이 질환은 부신피질호르몬제에 비교적 빠른 반응을 보이며 조기 진단으로 완치가 가능하지만 성급한 치료종결시 재발이 잘 되며 급격한 호흡부전으로 사망할 수도 있는 질환이므로 BOOP가 의심되고 치료에도 병이 진행성일 때 적기에 조직검사를 통해 확진함이 중요하다.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.161-163
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• 2002

The BNCT(Boron Neutron Capture Therapy) facility has been developed in Hanaro(High-flux Advanced Neutron Application Reactor), a research reactor of Korea Atomic Energy Research Institute. A typical tangenial beam port is utilized with this BNCT facility. Thermal neutrons can be penetrated within the limits of the possible maximum instead of being filtered fast neutrons and gamma rays as much as possible using the silicon and bismuth single crystals. In addition to, the liquid nitrogen (LN$_2$) is used to cool down the silicon and bismuth single crystals for the increase of the penetrated thermal neutron flux. Neutron beams for BNCT are shielded using the water shutter. The water shutter was designed and manufactured not to interfere with any other subsystem of Hanaro when the BNCT facility is operated. Also, it is replaced with conventional beam port plug in order to cut off helium gas leakage in the beam port. A circular collimator, composed of $\^$6/Li$_2$CO$_3$ and polyethylene compounds, is installed at the irradiation position. The measured neutron flux with 24 MW reactor power using the Au-198 activation analysis method is 8.3${\times}$10$\^$8/ n/cm$^2$ s at the collimator, exit point of neutron beams. Flatness of neutron beams is proven to ${\pm}$ 6.8% at 97 mm collimator. According to the result of acceptance tests of the water shutter, the filling time of water is about 190 seconds and drainage time of it is about 270 seconds. The radiation leakages in the irradiation room are analyzed to near the background level for neutron and 12 mSv/hr in the maximum for gamma by using BF$_3$ proportional counter and GM counter respectively. Therefore, it is verified that the neutron beams from BNCT facility in Hanaro will be enough to utilize for the purpose of clinical and pre-clinical experiment.

• 산업진흥연구
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• 제2권1호
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• pp.39-44
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• 2017

본 연구는 내일채움공제 제도가 대구.경북지역 중소기업 근로자의 직무만족도에 미치는 영향을 분석하였다. 연구결과를 요약하면 다음과 같다. 조사대상은 내일채움공제에 가입한 중소기업 근로자로 총 159명이며, 분석 자료는 SPSS Statistics 20을 사용하여 빈도분석, 요인분석, 신뢰도분석, 상관관계분석, 회귀분석 및 사후분석을 포함한 분산분석을 실시하였다. 분석결과 첫째, 내일채움공제 제도 요인 중 방법의 적합성이 직무만족도에 가장 높은 긍정적인 영향을 미치는 것으로 나타났다. 둘째, 내일채움공제 가입 후 업무만족도의 상관관계는 적합성(p<.01, ${\beta}=.307$)과 효율성(p<.01, ${\beta}=.296$)이 업무만족도에 유의한 영향을 미치는 것으로 나타났다. 셋째, 내일채움공제 제도에 가입한 근로자의 학력에 따른 직무만족도 차이분석은 전문대졸(2.08)이 대졸(1.99) 보다 직무만족도에 더 높은 것으로 분석 되었다. 본 연구는 내일채움공제 제도가 직무만족도에 미치는 영향력을 분석함으로써 삶의 질, 업무만족도, 근속성 요인의 중요도를 파악하고 근로자의 인구통계학적 특성에 따른 차이분석을 알아보고 내일채움공제 제도가 고용유지 및 직장 생활안정에 도움을 주어 직무만족도에 영향을 미치고 그 효과성을 검증 했다는데 연구의 의미가 있다.

• Archives of Plastic Surgery
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• 제38권3호
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• pp.228-234
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• 2011

Purpose: Reconstruction of chest wall has always been a challenging problem. Muscle flaps for chest wall reconstruction have been helpful in controling infection, filling dead space and covering the prosthetic material in this challenge. However, when we use muscle flaps, functional and cosmetic donor site morbidities could occur. The authors applied and revised various partial muscle flaps and combination use of them to cover the prosthetic material for the chest wall reconstruction and evaluated the usefulness of partial muscle flaps. Methods: This study included 7 patients who underwent chest wall reconstruction using partial muscle flap to cover prosthetic material from 2004 to 2008. The pectoralis major muscle was used in anterior 2/3 parts of it leaving lateral 1/3 parts of it. The anterior 2/3 parts of the pectoralis major muscle were used while lateral 1/3 parts were left. In case of the rectus abdominis muscle flap, we used upper half of it, or we dissected it around its origin and then advanced to cover the site. The latissimus dorsi muscle flap was elevated with lateral portion of it along the descending branch of the thoracodorsal artery. If single partial muscle flap could not cover whole prosthetic material, it would be covered with combination of various partial muscle flaps adjacent to the coverage site. Results: Flap coverage of the prosthetic material and chest wall reconstructions were successfully done. There occurred no immediate and delayed post operative complications such as surgical site infection, seroma, deformity of donor site and functional impairment. Conclusion: When we use the muscle flaps to cover prosthetic material for chest wall reconstruction, use of the partial muscle flaps could be a good way to reduce donor site morbidity. Combination of multiple partial flaps could be a valuable and good alternative way to overcome the disadvantages of partial muscle flaps such as limitation of volume and size as well as flap mobility.