• 한국지반신소재학회논문집
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• 제14권1호
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• pp.51-58
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• 2015

압성토공법은 성토체의 안정성을 높이기 위하여 성토체 측면에 일정한 폭과 높이로 흙을 쌓은 공법을 말한다. 본 연구는 실제 도로현장에서 전단파괴가 발생되어 복구방법으로 압성토공법을 적용한 시공사례를 분석한 것이다. 본 연구는 수치해석을 실시하여 효율적인 압성토 단면을 제시하고자 한다. 수치해석결과 효율적인 압성토 단면은 압성토 폭 : 제체 높이의 2배(2H), 압성토 높이 : 제체높이의 1/3(H/3) 이다. 또한, 압성토체를 가로지르는 측구를 설치할 경우, 본성토체로부터 적절한 이격거리를 제시함으로서 효과적인 횡단측구의 범위를 제시하였다.

• Steel and Composite Structures
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• 제24권5호
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• pp.549-559
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• 2017

As few multi-tower single-box multi-cell cable-stayed bridges with corrugated steel webs have been built, analysis is mostly achieved by combining single-girder model, beam grillage model and solid model in support of the design. However, such analysis methods usually suffer from major limitations in terms of the engineering applications: single-girder model fails to account for spatial effect such as shear lag effect of the box girder and the relevant effective girder width and eccentric load coefficient; owing to the approximation in the principle equivalence, the plane grillage model cannot accurately capture shear stress distribution and local stress state in both top and bottom flange of composite box girder; and solid model is difficult to be practically combined with the overall calculation. The usual effective width method fails to provide a uniform and accurate "effective length" (and the codes fail to provide a unified design approach at those circumstance) considering different shear lag effects resulting from dead load, prestress and cable tension in the construction. Therefore, a novel spatial grid model has been developed to account for shear lag effect. The theoretical principle of the proposed spatial grid model has been elaborated along with the relevant illustrations of modeling parameters of composite box girder with corrugated steel webs. Then typical transverse and longitudinal shear lag coefficient distribution pattern at the side-span and mid-span key cross sections have been analyzed and summarized to provide reference for similar bridges. The effectiveness and accuracy of spatial grid analysis methods has been finally validated through a practical cable-stayed bridge.

• 전력전자학회논문지
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• 제16권6호
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• pp.610-617
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• 2011

본 논문은 공간벡터펄스 변조법(SVPWM, Space Vector Pulse Width Modulation)을 사용하는 3상 인버터의 새로운 데드타임 직접 보상 방법을 제안한다. 제안된 데드타임 보상방식은 인버터에 인가되는 데드타임을 중간상 전류의 방향에 따라, 유효전압이 인가되는 유효전압벡터 인가시간에서 직접 보상하는 방식이다. 3상 인버터에서 각상에 인가되는 전압의 크기는 유효전압이 인가되는 시간에 의해 결정되고, 데드타임의 영향에 따라, 실제로 유효전압이 인가되는 스위칭 시간은 전류의 방향에 따라 손실이 발생하게 된다. 제안된 방식에서는 실제로 전류의 방향에 따라 손실이 발생하는 유효전압벡터의 인가시간에 직접적으로 손실 시간을 더하여 유효전압벡터의 인가시간을 계산하는 방식으로 별도의 전압오차를 보상하기 위한 제어기와 복잡한 d-q 변환을 필요로 하지 않는 장점이 있다. 제안된 방식은 3상 R-L 부하에 대하여 컴퓨터 모의해석과 실험을 통하여 제안된 방식의 데드타임 보상을 검증하였다.

• 대한토목학회논문집
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• 제31권6D호
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• pp.755-764
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• 2011

현재 주차장 내 주차단위구획과 차로너비 규정의 경우 주차장법 시행규칙의 '주차장 구조 및 설치기준'에 의거하여 계획설치되고 있다. 그러나 최근 RV차량 및 대형승용차가 급속히 증가하는 추세에서, 기존의 주차단위구획의 설치기준으로는 주차시 발생하는 차량훼손 민원, 주차장 이용자의 통행불편, 주차장 유지 관리 등의 문제를 해소하기 힘든 실정이다. 이에 본 연구는 현실에 적합한 주차단위구획과 차로너비 규정의 재정비가 필요하다는 판단 하에, 최근 증가하는 국내 외 RV차량 및 대형승용차의 차량제원, 최소 회전반경, 주차시 운전자 주행행태 등을 고려하여 주차단위구획 및 차로너비를 산정하였다. 산정된 주차단위구획 및 차로너비를 국외 사례와 비교 분석한 후, 기존보다 확대된 주차단위구획 및 차로너비를 이용하여 주차시 운전자의 편의성 및 비용적 측면을 고려한 최적의 개선방안을 제시하였다. 또한, 교통안전을 고려한 주차단위구획과 차로너비의 개선방안, 그리고 차종별 주차계획 방법을 제시하였다. 주차장 내 원활한 차량소통과 안전을 도모한 주차계획단위 산정 및 주차계획 방법을 제시함으로써, 향후 주차장의 구조, 설치기준의 정립과 주차장 교통안전 개선에 이바지할 것으로 판단된다.

• 한국임상수의학회지
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• 제23권2호
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• pp.133-143
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• 2006

Diagnosis on reproductive failures of dairy cows by ultrasonography was performed for 151 dairy cows. To diagnose types of reproductive failures, ultrasonography (SA 600, Medison, 5.0 MHz rectal linear transducer) was carried out in combination with rectal examination. Of 151 dairy cows, pregnant cows were 13 and the cows in normal estrual cycle were 40 cows, thereby the cows with reproductive failures were 98 cows. 1. Of 98 cows with reproductive failures, the cows with ovarian diseases were 34 cows (34.7%) and the cows with uterine diseases were 41 cows (41.8%). 2. The diameter of follicle in proestrus was 1.94 cm and it was longer than that of follicle in diestrus (p<0.05). 3. The mean size of corpus luteum of pregnant cows was bigger than that of corpus luteum in normal diestrus (p<0.05). 4. The length of cystic corpus luteum was 3.26 and the width of that was 1.91 cm. The length of corpus luteum tissue was 1.95 and the width of that was 1.91 cm excluding the size of cavity in corpus luteum. 5. The mean length of follicular cyst was 3.31 and the mean width of that was 2.3 cm. 6. The mean length and width of luteal cyst was 3.45 and 2.25 cm, respectively. The mean length and width of corpus luteum tissue was 1.15 and 0.67 cm, respectively, excluding the size of cyst in the luteal cyst. 7. The width of uterine horn associated with endometritis was significantly reduced as the period after parturition was elapsed (p<0.05). The mean width of uterine horn within 40 days after parturition was 4.55 cm. These results indicated that ultrasonography is of great use for accurate diagnosis both on ovarian diseases and uterine diseases and that it is very effective to diagnose endometritis in dairy cows.

• Journal of Periodontal and Implant Science
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• 제46권5호
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• pp.329-336
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• 2016

Purpose: The aim of this study was to clinically assess the impact of a prefabricated implant-retained stent clipped over healing abutments on the preservation of keratinized mucosa around implants after implant surgery, and to compare it with horizontal external mattress sutures. Methods: A total of 50 patients were enrolled in this study. In the test group, a prefabricated implant-retained stent was clipped on the healing abutment after implant surgery to replace the keratinized tissue bucco-apically. In the control group, horizontal external mattress sutures were applied instead of using a stent. After the surgical procedure, the width of the buccal keratinized mucosa was measured at the mesial, middle, and distal aspects of the healing abutment. The change in the width of the buccal keratinized mucosa was assessed at 1 and 3 months. Results: Healing was uneventful in both groups. The difference of width between baseline and 1 month was $-0.26{\pm}0.85mm$ in the test group, without any statistical significance (P=0.137). Meanwhile, the corresponding difference in the control group was $-0.74{\pm}0.73mm$ and it showed statistical significance (P<0.001). The difference of width between baseline and 3 months was $-0.57{\pm}0.97mm$ in the test group and $-0.86{\pm}0.71mm$ in the control group. These reductions were statistically significant (P<0.05); however, there was no difference between the 2 groups. Conclusions: Using a prefabricated implant-retained stent was shown to be effective in the preservation of the keratinized mucosa around implants and it was simple and straightforward in comparison to the horizontal external mattress suture technique.

• 한국전기전자재료학회논문지
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• 제17권5호
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• pp.508-514
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• 2004

A fluxgate magnetic sensor consists of a solenoid excitation coil, pick-up coil, and magnetic core. We presents the effect of magnetic core shape in a micromachined fluxgate sensor. To observe the performance of fluxgate sensor with magnetic core side width and gap, side width of 125 ${\mu}{\textrm}{m}$, 250 ${\mu}{\textrm}{m}$, and 500 ${\mu}{\textrm}{m}$ were designed in a rectangular-ring shaped core and the gaps of 0 ${\mu}{\textrm}{m}$, 50 ${\mu}{\textrm}{m}$, and 100 ${\mu}{\textrm}{m}$ were also fabricated in a racetrack shaped core. The solenoid coils and magnetic core were separated by benzocyclobutane(BCB) which had high insulation and good planarization characters. Copper coil patterns of 10 ${\mu}{\textrm}{m}$ width and 6${\mu}{\textrm}{m}$ thickness were electroplated on Ti(300 $\AA$) / Cu(1500 $\AA$) seed layers. 3 ${\mu}{\textrm}{m}$ thick N $i_{0.8}$F $e_{0.2.}$(permalloy) film for the magnetic core was also electroplated under 2000 gauss to induce the magnetic anisotropy. The magnetic core had the high DC effective permeability of ∼1,300 and coercive field of ∼0.1 Oe. Because the magnetic cores of 500 ${\mu}{\textrm}{m}$ side width and 0 gap had a low magnetic flux leakage, high sensitivity of ∼350 V/T were measured at excitation condition of 3 $V_{P-P}$ and 2 MHz square wave. The power consumption of ∼14 ㎽ was measured. The fabricated fluxgate sensor had the very small actual size of 3.0${\times}$1.7 $\textrm{mm}^2$. When two fluxgates were perpendicularly aligned in terrestrial field, their two-axis output signals were very useful to commercialize an electronic azimuth compass for the portable navigation system.m.m.m.

• 생명과학회지
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• 제10권4호
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• pp.317-325
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• 2000

A six parent dialled analysis was conducted to get basic information for improving yield of upland cotton. Heterosis, combining ability, genetic components and correlation coefficients for boll length, boll width, boll weight, 100 seed weight, lint weigth per boll and lint percentage were studied. Estimates of heterosis for all characters and heterobeltiosis for boll weight and lint weight per boll showed positive values. In general combining ability effect, 'Muan' and 'Imsung' showed highely positive effect in all characters. In specific combining ability effect, the combinations of 'Seungju${\times}$Imsung$.$Seosan${\times}$Imsung' for bll length, 'Cheju${\times}$Imsung$.$Seung${\times}$Imsung' for boll width, 'Cheju${\times}$Muan$.$Cheju${\times}$Imsung' for boll weight, 'Cheju${\times}$Soonchun$.$Muan${\times}$Imsung' for 100 seed weight, 'Soonchun${\times}$Muan' for lint weight per boll and 'Soonchun${\times}$Seosan$.$Seungju${\times}$Muan' for lint percentage showed highly positive effect. Partial dominance was observed for boll length, boll weight, 100 seed weight and lint weight per boll, complete dominance for boll width and overdominance for lint percentage. The number of effective gene group was estimated as one for all characters. The estimates of narrow and broad sense heritabilities were high for all characters except as one for all characters. The estimates of narrow and broad sense heritabilities were high for all characters except lint percentage. Correlation coefficients among the boll length, boll width, boll weight, 100 seed weight and lint weight per boll were positive, whereas lint percentage was negatively correlated with other characters.

• 대한기계학회논문집A
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• 제35권12호
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• pp.1641-1646
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• 2011

자기연마공정은 유동성이 높은 연마입자를 활용하기 때문에 곡면 및 그루브 형상에도 적용이 가능한 장점을 지니고 있다. 본 연구에서는 제 2세대 자기연마법을 활용하여 그루브 형상에 대한 자기연마가공 특성을 평가하여, 이를 향후 연료전지 채널과 같은 3차원 형상의 자기연마에 활용하고자 한다. 실험은 최대 1.5mm 깊이의 그루브에 대해 자기연마가공 후 슬롯부 및 랜드부의 표면거칠기 변화를 관찰하였다. 그 결과 랜드부의 길이가 증가하고 그루브의 깊이가 깊어질수록 랜드부의 표면거칠기 향상정도는 높아졌다. 또한 슬롯부의 표면거칠기 향상정도는 랜드부와 슬롯부의 길이비가 증가하고 그루브의 깊이가 깊어질수록 감소하는 경향을 나타내었다. 마지막으로 자기연마가공을 통해서 그루브의 형상에는 큰 변화없이, 그루브의 모서리에 생성된 버를 효과적으로 제거할 수 있었다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제29권6호
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• pp.407-420
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• 2003

Purpose : The purpose of this study was to analyse the facial changes and factors contributing to then after bilateral sagittal split ramus osteotomy of mandibular prognathism. Materials and Methods : Forty patients with Class III dental and skeletal malocclusion who were treated with bilateral sagittal split ramus osteotomy were reviewed. Frontal and lateral cephalometric radiographs were taken preoperatively, immediate postoperatively and more than six months postoperatively in each patient. After tracing the cephalometric radiographs, various parameters were measured. Results : 1. Gonial angle at postoperative two days was decreased about $10.4^{\circ}$ than preoperatively and gonial angle at postoperative six months was increased about $6.8^{\circ}$ than postoperative two days. So, gonial angle at postoperative six months was decreased about $3.6^{\circ}$ than preoperative gonial angle. 2. Facial height postoperative two days was decreased about 0.8mm than preoperatively and facial height at postoperative six months was decreased about 0.7mm than postoperative two days. So, facial height at postoperative six months was decreased about 1.5mm than preoperative facial height. 3. Mandibular width postoperative two days was decreased about 1.0mm than preoperatively and mandibular width at postoperative six months was increased about 1.8mm than postoperative two days. So, mandibular width at postoperative six months was decreased about 2.8mm than preoperative mandibular width. 4. Amount of set back and mandibular plane angle were not influencing on relapse degree. Conclusion : It is thought that bilateral sagittal split ramus osteotomy in mandibular prognathic patients is effective to improve long face and steep gonial angle. More prudent operation and careful postoperative management is required to maintain stable face postoperatively. Further research for soft tissue changes and factors which are related with relapse is needed.