• 조명전기설비학회논문지
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• 제22권10호
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• pp.18-23
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• 2008

한국은 1970년대 이후 지속적인 경제성장으로 인해 전력수요가 꾸준히 증가해 왔다. 이러한 전력수요를 충족시키기 위해 설비의 확장을 통한 공급측 관리(Supply-Side Management)와 함께 전력사용의 효율성을 향상시킴으로써 안정적인 전력을 공급하는 수요측 관리(Demand-Side Management)를 수행하고 있으며, 전세계적인 에너지 사용량 증가로 인해 연료비용이 점차 커지면서 수요측 관리의 중요성이 점차 커지고 있다. 수요측 관리는 지원금을 이용하여 전력수요를 조절하고 있으며, 수요관리의 중요성이 커짐에 따라 지원금 규모는 점점 커지고 있다. 하지만 현재 지원금 산정에 대한 구체적인 연구가 진행되고 있지 않은 실정이므로 이에 대한 연구를 통해 더욱 효율적인 지원금 산정을 통한 수요관리 효과를 극대화 할 필요가 있다. 본 논문에서는 2007년도에 지원금 변화에 대한 잠재참 여자의 선호도를 조사한 "지원금에 대한 수용가 반응도 조사"를 이용하여, 지원금 변화에 따른 수요관리 프로그램의 잠재참여자의 참여도를 수식화 함으로써 지원금 변화에 대한 수요관리 프로그램의 영향도를 분석할 수 있게 하는데 목적을 두고 있다.

• 한국구조물진단유지관리공학회 논문집
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• 제19권5호
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• pp.67-74
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• 2015

콘크리트 구조물은 경제적이고 내구적인 구조물이지만 철근부식에 따라 성능이 내구적, 구조적 저하하게 된다. 최근들어 내구성설계가 도입되고 있는데, 콘크리트 구조물의 내구수명은 해수에 같이 노출되더라도, 국부적인 노출환경과 설계방법에 따라 다르게 평가된다. 본 연구는 3.5년~4.5년 해수에 노출된 4개의 RC 교각을 대상으로 실태조사를 수행하여 25개의 콘크리트 코어를 채취하였으며, 전염화물을 평가하여 표면염화물량 및 겉보기 확산계수를 도출하였다. Fick's $2^{nd}$ Law를 기본으로 한 결정론적 방법과 임계확률을 고려한 확률론적인 방법을 수행하여 내구수명을 각각 평가하고 분석하였다. 확률론적인 방법은 보수적으로 평가되었으며, 같은 구조물이라 하더라도 간만대 및 40.0 m 이상의 비말대에서는 비교적 낮은 내구수명이 평가되었다. 본 연구에서는 코어채취높이에 따른 염화물 거동 분석과 내구성 설계방법의 현시점에서의 한계성이 분석되었다.

• 재활복지공학회논문지
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• 제8권2호
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• pp.79-88
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• 2014

국내에서 전기적 자극방식 삼킴 보조 치료기는 높은 보급률과 사용빈도를 가진 전문 의료기기임에도 불구하고 기기에 대한 관리체계가 전무하여 유지 보수의 측면에 있어서도 매우 큰 취약성을 노출해 왔다. 이에 본 연구는 전기적 자극방식 삼킴 보조 치료기의 장비관리 및 안전진단 매뉴얼 개발에 목적을 두고 프로그램을 개발하였다. 이를 위하여 국제전기기술위원회(International Electrotechnical Commission, IEC)등의 기관에서 공시한 표준화된 프로그램 수집과 문헌고찰을 통해 매뉴얼 개발의 근거를 마련하고, 프로토콜을 개발하여 제시하였다. 완성된 알고리즘과 프로토콜, 지표 등의 자료를 전문가 및 현장 실무자의 자문을 통하여 수정 및 보완하고 유지보수 워크시트(Maintenance Worksheet)의 5지표 18항목, 삼킴 보조 전자 의료기기 장비관리/안전진단 절차 매뉴얼(Equipment Procedure Manual)에서 4개 지표 32항목으로 구성된 점검 매뉴얼을 최종적으로 완성하였다. 완성된 지표는 장비의 고장률을 줄이고 의료기록 문서화의 체계성 제고에 도움을 줄 것이며, 의료서비스의 효율성, 적절성을 유지하는데 기여할 수 있을 것이라 생각된다.

• 대한소아치과학회지
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• 제38권4호
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• pp.348-354
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• 2011

침식 법랑질의 표층은 건전 법랑질과는 물리화학적 성상이 다르므로 침식 법랑질면에 대한 복합레진의 결합력을 증가시키기 위한 대안으로, 법랑질 내층으로의 침투력이 탁월한 infiltrant resin을 응용하는 방법을 생각하게 되었다. 본 연구는 다양한 정도로 인공 침식이 유발된 법랑질면을 대상으로, infiltrant resin과/또는 기존의 접착제를 적용한 경우의 복합레진 결합강도를 비교 분석할 목적으로 시도되었다. 건전한 순면을 가진 발거된 상악 유전치를 대상으로, 인공침식 유발 횟수 및 infiltrant resin과/또는 기존의 접착제를 적용한 방법에 따라 각 20개씩의 시료를 제작하였으며, 각 군의 미세인장 결합강도를 측정하고, 파절면의 파절 양상을 평가하여 다음과 같은 결과를 얻었다. 법랑질 표면의 침식 유발 횟수가 늘어날수록 결합강도가 낮았다(p<0.05). 기존의 접착제 상부에 infiltrant resin을 추가 적용한 군, infiltrant resin만 적용한 군, 접착제만 적용한 군의 순으로 미세인장결합강도가 높게 나타났다(p<0.05). 파절 양상의 관찰에서는 인공 침식 유발 횟수가 적은 군 및 infiltrant resin을 적용한 군에서 응집파절의 비율이 높게 나타났다. 결론적으로, 법랑질의 침식도가 클수록 복합레진 수복물과의 결합 강도는 감소하였으며, infiltrant resin으로 기존의 적찹제를 대체하거나 첨가함으로써 결합강도를 보완시킬 수 있을 것으로 판단되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제27권10호
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• pp.1417-1425
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• 2014

The selection of morphologically normal spermatozoa is critical to obtain high breeding performances in boar breeding farms and artificial insemination (AI) centers. Parameters for the selection of semen mainly include total sperm motility, concentration, and morphology. However, these primary parameters are often not reliable for discriminating between normal and abnormal, non-fertilizable spermatozoa. The present study was designed to compare the motion characteristics, fertilization ability using in vitro fertilization (IVF), and acrosome formation of the semen from boars having low (boar number 2012) and normal (boar number 2004 and 2023) breeding performances. The ultimate goal was to identify additional simple and easy criteria for the selection of normal sperm. There was no significant difference between boar 2004 and boar 2023 sperm total motility in computer assisted sperm analysis. However, boar number 2012 semen presented a significantly reduced population of rapid moving spermatozoa and an increased population of slow moving spermatozoa compared to boar numbers 2004 and 2023. Analysis of detailed motion characteristics revealed that sperm from boar number 2012 had significantly reduced motility in progressiveness, average path velocity, straight-line velocity (VSL), curvilinear velocity (VCL), straightness, and linearity. The assessment of the fertilizing ability by IVF also showed that sperm from boar number 2012 showed a fertility rate of 3.4%, whereas sperm from boar number 2023 had a fertility rate of 75.45%. Interestingly, most of the sperm nuclei were found on the peripheral area of the oocytes, suggesting that the sperm from boar number 2012 lacked penetration ability into the oocyte zonapellucida. The acrosome formation analysis using Pisum sativum agglutinin staining demonstrated that the sperm from boar number 2012 had a defect in acrosome formation. Consequently, primary parameters for selecting semen before AI such as motility are not sufficient to select normal and fertilizable spermatozoa. In conclusion, the present study suggests that the acrosome staining and detailed motion characteristics such as progressiveness, VCL, and VSL should be included in determining semen quality together with primary parameters for successful AI and high breeding performance in the swine industry.

• The Korean Journal of Pain
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• 제22권2호
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• pp.158-162
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• 2009

Background: The loss of resistance (LOR) method is most commonly used to identify the epidural space. This method is thought to rely on the penetration of the ligamentum flavum. Unfortunately the exact morphology of the ligamentum flavum is variable at different vertebral levels. Especially, it has been pointed out that the lower cervical ligamentum flavum may be discontinuous in the midline in up to 50% of patients. Thus, the LOR method may be inaccurate to confirm the cervical epidural space. The aim of this study is to determine which method is the safest and most exact for confirming the cervical epidural space. Methods: 100 adult, chronic renal failure patients who were undergoing an arteriovenous bridge graft for hemodialysis at the upper arm under cervical epidural anesthesia were recruited for this study. During the cervical epidural puncture, we identified the cervical epidural space by subjectively feeling the resistance with using a finger just through the ligamentum flavum, and we also used the drip infusion method, the loss of resistance method using air, and the hanging drop method. By using 5 grades, we classified the extent of whether or not the techniques were effective. Results: Using the drip infusion method, we identify the epidural space in all the patients as ＋/＋＋ grade. The catheter insertion method was also successful in identifying those epidural spaces over a ${\pm}$ grade. The pseudo LOR was over ${\pm}$ grade in 47 patients. Conclusions: The combined LOR/hanging drop with drip infusion method is useful for confirming the cervical epidural space.

• Nuclear Engineering and Technology
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• 제53권9호
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• pp.3068-3084
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• 2021

Investigations of large commercial aircraft impact effect on nuclear power plant (NPP) buildings have been drawing extensive attentions, particularly after the 9/11 event, and this paper aims to experimentally assess the damage and vibrations of NPP buildings subjected to aircraft crash. In present Part I, two shots of reduce-scaled model test of aircraft impacting on NPP building were carried out. Firstly, the 1:15 aircraft model (weighs 135 kg) and RC NPP model (weighs about 70 t) are designed and prepared. Then, based on the large rocket sled loading test platform, the aircraft models were accelerated to impact perpendicularly on the two sides of NPP model, i.e., containment and auxiliary buildings, with a velocity of about 170 m/s. The strain-time histories of rebars within the impact area and acceleration-time histories of each floor of NPP model are derived from the pre-arranged twenty-one strain gauges and twenty tri-axial accelerometers, and the whole impact processes were recorded by three high-speed cameras. The local penetration and perforation failure modes occurred respectively in the collision scenarios of containment and auxiliary buildings, and some suggestions for the NPP design are given. The maximum acceleration in the 1:15 scaled tests is 1785.73 g, and thus the corresponding maximum resultant acceleration in a prototype impact might be about 119 g, which poses a potential threat to the nuclear equipment. Furthermore, it was found that the nonlinear decrease of vibrations along the height was well reflected by the variations of both the maximum resultant vibrations and Cumulative Absolute Velocity (CAV). The present experimental work on the damage and dynamic responses of NPP structure under aircraft impact is firstly presented, which could provide a benchmark basis for further safety assessments of prototype NPP structure as well as inner systems and components against aircraft crash.

• 대한치과보철학회지
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• 제35권4호
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• pp.647-661
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• 1997

The resin modified glass ionomer cements(RMGICs) have been used for years since 1989. Recently it has been developed for luting of fixed restorations. To evaluate the bond strength and marginal leakage of RMGICs for luting usage, the 80 extracted human molars which had uniform area of exposed dentin were cemented with 3 types of RMGICs(Fuji Duet, Advance, Vitremer), a conventional Glass Ionomer Cement(GIC-Fuji I), and a resin cement (Panavia 21) to base metal alloy(Ni-Cr-Be). After thermocycling the specimens were immersed in basic fuschin dye for measuring marginal leakage. The shear bond strength was measured with Instron and the maximum dye penetration was measured to 0.1mm. The types of fractured patterns were determined with stereoscope(${\times}7.5$). The results are as follows. 1. The difference between 3 RMGICs and a conventional GIC in shear bond strength was not statistically significant. It seemed that RMGICs had lower shear bond strength than resin cement. (p<0.01) 2. The mean scores of marginal leakage had no significant difference between the resin cement and 3 RMGICs but it was much higher in conventional GIC than the RMGICs (p<0.05) 3. It was determined that the manufacturer and the methods of dentin pretreatment determined the pattern of fracture surfaces and the frequency of adhesive failure between teeth and 3 RMGICs standed as in following order - Vitremer, Advance, Fuji Duet. (p<0. 01) When the fracture pattern was analyzed, it could be said that the materials and the method of dentin pretreatment have much effect on bonding states. This means that the dentin bonding agents should be improved. But the limited products in this experiment can not evaluate the physical properties of the entire RMGICs. Therefore a further study which can evaluate various RMGICs should be in progress to develope better cements.

• Journal of Periodontal and Implant Science
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• 제37권2호
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• pp.237-249
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• 2007

This study was performed to evaluate the effect of membrane exposure on new bone formation when guided bone regeneration with perforated titanium membrane on atrophic alveolar ridge. The present study attempted to establish a GBR model for four adult beagle dog premolar. Intra-marrow penetration defects were created on the alveolar ridge(twelve weeks after extraction) on the mandibular premolar teeth in the beagle dogs. Space providing perforated titanium membrane with various graft material were implanted to provide for GBR. The graft material were demineralized bovine bone(DBB), Irradiated cancellous bone(ICB) and demineralized human bone powder(DFDB). The gingival flap were advanced to cover the membranes and sutured. Seven sites experienced wound failure within 2-3weeks postsurgery resulting in membrane exposure. The animals were euthanized at 4 weeks postsurgery for histologic and histometric analysis. The results of this study were as follows: 1. There was little new bone formation at 4 weeks postsurgery. irrespectively of membrane exposure. 2. There was significant relationship between membrane exposure and bone graft resorption(P<0.05), but no relation between membrane exposure and infiltrated connective tissue. 3. There was much bone graft resorption on DFDB than ICB and DBB. 4. The less exposure was on the perforated titanium membrane, the more dense infiltrated connective tissue was filled under the membrane when grafted with ICB and DBB. but there was no relationship between the rate of membrane exposure and the percentage of infiltrated connective tissue area and no relationship between the percentage of the area in the infiltrated connective tissue and in the residual bone graft. Within the above results, bone formation may be inhibited when membrane was exposed and ICB and DBB were more effective than DFDB as a bone graft material when guided bone regeneration.

• 대한소아치과학회지
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• 제46권2호
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• pp.165-172
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• 2019

이 논문의 목적은 기능성 모노머를 함유한 8세대 접착제의 적용시간 감소와 인산 산부식 여부가 유치에서 접착능에 미치는 영향을 평가하는 것이다. 80개의 우식이 없는 유구치를 선정하였고, 접착제의 종류에 따라서 2그룹으로 분류하였다(G-premio bond, Single bond universal). 각 그룹은 적용 시간와 인산 산부식 여부에 따라서 그룹당 10개씩, 총 4개의 하위그룹으로 추가 분류하였다. 각 하위그룹은 절반으로 나누어, 5개의 시편은 전단결합강도 측정 후 주사전자현미경을 촬영하여 파절양상을 확인하였고, 다른 5개의 시편은 미세누출을 측정하였다. G-premio bond는 적용시간와 인산 산부식 여부에 따른 결합강도와 파절양상, 미세누출의 유의한 차이가 관찰되지 않았다. Single bond universal은 적용시간을 길게 한 경우가 적용시간이 짧은 경우에 비해서 유의하게 높은 전단결합강도를 보였다(p = 0.014). 모든 그룹에서 나타난 전단결합강도는 임상적으로 허용 가능한 전단결합강도인 17 MPa 보다 높았다. G-premio bond는 인산 산부식 없이 적용시간을 줄여서 사용하는 방법이 가능하다.