• 한국분무공학회지
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• 제24권2호
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• pp.66-72
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• 2019

Diesel vehicles suffer from poor starting and running problems at cold temperatures. Diesel vehicles have the characteristic that CO and PM are reduced or similarly discharged when going from low temperature to high temperature. In this study, a bypass type piezo injector for electronic control based common rail injection system was used. Numerical analysis using injector drive analysis model was performed to analyze injector drive and internal fuel flow characteristics according to fuel temperature change. The results show that the rate of density change due to the fuel temperature is proportional, and that the effect of the kinematic viscosity is relatively large between $-20^{\circ}C$ and $0^{\circ}C$. Comparing the results of temperature condition at $0^{\circ}C$ and $20^{\circ}C$, it is considered that the viscosity is more correlated with the needle displacement than the pressure chamber of the delivery chamber.

• Clinics in Shoulder and Elbow
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• 제22권2호
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• pp.106-109
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• 2019

Acromial fractures are well-documented complications subsequent to reverse shoulder arthroplasty (RSA), and most appear as stress fractures with no history of single trauma. To date, no study has reported the occurrence of acute displaced acromial fracture due to sudden strong deltoid contraction during heavy work. Displacement of the fracture results in a challenging surgery since it is difficult to obtain adequate fixation in thin and osteoporotic bones. We report a rare case of acute displaced acromial fracture after successful RSA treatment, using a novel technique of open reduction and internal fixation, applying two 4.5 mm cannulated screws and lateral clavicle precontoured plate.

• Journal of Electrical Engineering and information Science
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• 제1권1호
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• pp.58-69
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• 1996

This paper presents a new approach to derive an energy integral based on an Equivalent Mechanical Model(EMM), which is developed by introducing imaginary springs for line resistances. The proposed EMM shows that phasor currents and voltages are directly analogous to the two-dimensional force and displacement vectors, respectively. Through rigorous energy analysis of the proposed EMM, an exact energy integral expression is derived for multimachine systems, and several useful theorems are developed to derive an energy integral for power systems with detailed generator models the energy integral exactly reflects the internal resistance, saliency and flux-decaying effects of the generator. Finally, an illustrative example is given for a multimachine system adopting the Eq'-model for generators, which shows that the consideration of a detailed generator model does not aggravate the complicacy of the direct method of stability analysis in multimachine systems.

• 반도체디스플레이기술학회지
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• 제23권1호
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• pp.52-55
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• 2024

In this paper, a state change study was conducted through Frequency Domain Reflectometry (FDR) technology for the process chamber of plasma equipment for semiconductor manufacturing. In the experiment, by direct connecting the network analyzer to the RF matcher input of the 300 mm plasma enhanced chemical vapor deposition (PECVD) chamber, S11 was measured in a situation where plasma was not applied, and the frequency domain reacting to the chamber state change was searched. Response factors to changes in the status, such as temperature, spacing of the heating chuck, internal pressure difference, and process gas supply state were confirmed. Through this, the frequency domain in which a change in the reflection value was detected through repeated experiments. The reliability of the measured micro-displacement was verified through reproducibility experiments.

• 한국전산구조공학회논문집
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• 제37권1호
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• pp.67-76
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• 2024

본 논문에서는 역학적 변수들을 측정하는 방안으로 디지털 이미지 프로세싱과 강형식 기반의 MLS 차분법을 융합한 DIP-MLS 시험법을 소개하고 추적점의 위치와 이미지 해상도에 대한 영향을 분석하였다. 이 방법은 디지털 이미지 프로세싱을 통해 시료에 부착된 표적의 변위 값을 측정하고 이를 절점만 사용하는 MLS 차분법 모델의 절점 변위로 분배하여 대상 물체의 응력, 변형률과 같은 역학적 변수를 계산한다. 디지털 이미지 프로세싱을 통해서 표적의 무게중심 점의 변위를 측정하기 위한 효과적인 방안을 제시하였다. 이미지 기반의 표적 변위를 이용한 MLS 차분법의 역학적 변수의 계산은 정확한 시험체의 변위 이력을 취득하고 정형성이 부족한 추적 점들의 변위를 이용해 mesh나 grid의 제약 없이 임의의 위치에서 역학적 변수를 쉽게 계산할 수 있다. 개발된 시험법은 고무 보의 3점 휨 실험을 대상으로 센서의 계측 결과와 DIP-MLS 시험법의 결과를 비교하고, 추가적으로 MLS 차분법만으로 시뮬레이션한 수치해석 결과와도 비교하여 검증하였다. 이를 통해 개발된 기법이 대변형 이전까지의 단계에서 실제 시험을 정확히 모사하고 수치해석 결과와도 잘 일치하는 것을 확인하였다. 또한, 모서리 점을 추가한 46개의 추적점을 DIP-MLS 시험법에 적용하고 표적의 내부 점만을 이용한 경우와 비교하여 경계 점의 영향을 분석하였고 이 시험법을 위한 최적의 이미지 해상도를 제시하였다. 이를 통해 직접 실험이나 기존의 요소망 기반 시뮬레이션의 부족한 점을 효율적으로 보완하는 한편, 실험-시뮬레이션 과정의 디지털화가 상당한 수준까지 가능하다는 것을 보여주었다.

• International Journal of Control, Automation, and Systems
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• 제4권6호
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• pp.748-755
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• 2006

In this paper, a trade-off design and fabrication of IPMC(Ionic Polymer Metal Composites) as an actuator for a flapping device have been described. Experiments for the internal solvent loss of IPMCs have been conducted for various combinations of cation and solvent in order to find out the best combination of cation and solvent for minimal solvent loss and higher actuation force. From the experiments, it was found that IPMCs with heavy water as their solvent could operate longer. Relations between length/thickness and tip force of IPMCs were also quantitatively identified for the actuator design from the tip force measurement of 200, 400, 640, and $800{\mu}m$ thick IPMCs. All IPMCs thicker than $200{\mu}m$ were processed by casting $Nafion^{TM}$ solution. The shorter and thicker IPMCs tended to generate higher actuation force but lower actuation displacement. To improve surface conductivity and to minimize solvent evaporation due to electrically heated electrodes, gold was sputtered on both surfaces of the cast IPMCs by the Physical Vapor Deposition(PVD) process. For amplification of a short IPMC's small actuation displacement to a large flapping motion, a rack-and-pinion type hinge was used in the flapping device. An insect wing was attached to the IPMC flapping mechanism for its flapping test. In this test, the wing flapping device using the $800{\mu}m$ thick IPMC. could create around $10^{\circ}{\sim}85^{\circ}$ flapping angles and $0.5{\sim}15Hz$ flapping frequencies by applying $3{\sim|}4V$.

• Imaging Science in Dentistry
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• 제35권1호
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• pp.51-54
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• 2005

Purpose : To acquire the useful diagnostic information through the analysis of the clinical and radiological characteristics of mandibular odontogenic keratocyst. Materials and Methods : The researchers compared and analysed the clinical and radiological features of 112 cases of mandibular odontogenic keratocyst confirmed by histopathlogic examination. Results : Mandibular odontogenic keratocysts occurred more frequently in males than in females and the incidence is the highest in the 2nd and 3rd decades. These cysts occurred in the mandibular posterior area, angle-ramus area and anterior area $51.8\%$, $31.2\%$ and $17.0\%$ respectively. These cysts had undulating border ($69.6\%$) rather than smooth border ($30.4\%$). Most of these cysts had well-defined hyperostotic border ($94.6\%$). These cysts caused cortical thinning or expansion ($78.6\%$) rather than no cortical reaction ($21.4\%$). Loss of lamina dura was observed in $72.3\%$, displacement of tooth appeared in $35.7\%$ and root resolution appeared in $12.5\%$ of cases. In $71\%$ of cases, displacement of mandibular canal was observed. Internal patterns of lesional radiolucency were even ($61.6\%$) or uneven ($38.4\%$). Conclusion : These results would be helpful in diagnosing of mandibular odontogenic keratocyst. (Korean J Oral Maxillofac Radiol 2005; 35 : 51-4)

• Earthquakes and Structures
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• 제12권3호
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• pp.333-347
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• 2017

Masonry infill walls are unavoidable parts of any building to create a separation between internal space and external environment. In general, there are some prevalent openings in the infill wall due to functional needs, architectural considerations or aesthetic concerns. In current design practice, the strength and stiffness contribution of infill walls is not considered. However, the presence of infill walls may decisively influence the seismic response of structures subjected to earthquake loads and cause a different behavior from that predicted for a bare frame. Furthermore, partial openings in the masonry infill wall are significant parameter affecting the seismic behavior of infilled frames thereby decreasing the lateral stiffness and strength. The possible effects of openings in the infill wall on seismic behavior of RC frames is analytically studied by means of pushover analysis of several bare, partially and fully infilled frames having different bay and story numbers. The stiffness loss due to partial opening is introduced by the stiffness reduction factors which are developed from finite element analysis of frames considering frame-infill interaction. Pushover curves of frames are plotted and the maximum base shear forces, the yield displacement, the yield base shear force coefficient, the displacement demand, interstory drift ratios and the distribution of story shear forces are determined. The comparison of parameters both in terms of seismic demand and capacity indicates that partial openings decisively influences the nonlinear behavior of RC frames and cause a different behavior from that predicted for a bare frame or fully infilled frame.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제20권2호
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• pp.101-105
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• 1998

Compound comminuted mandibular fracture is defined as the presence of multiple fracture lines with open wound resulting in many small pieces within the same area. The incidence of mandibular comminution is difficult to determine but reported as 2.7~18.6 % incidence among mandibular fractures. There are controversies in the treatment of mandibular comminuted fractures. Treatment of comminuted mandibular fracture has traditionally involved closed reduction in an effort to avoid stripping periostcum from the bony segments, but rigid internal rigid fixation is used more popular at present. The extent of comminution, displacement of bony fragments and patient general conditions are important factors in decision of the treatment methods. When significant bone displacement is present, it is necessary to reduce these comminuted fragments to an anatomic, pretraumatic relationship to restore facial form and function. In these cases, ORIF allows anantomic reduction of comminuted segments as well as pretraumatic occlusion. Gentle handling of the soft tissue, rigid fixation of bony fragments and adequate immobilization are essential for reducing the complications. This is the report the incidence, causes, complications and treatment of the patients who visited our department for compound comminuted mandibular fractures.

• 대한족부족관절학회지
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• 제9권2호
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• pp.162-166
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• 2005

Purpose: To analyze the clinical and radiological feature of Os subfibulare and to evaluate the results after anatomical reduction and internal fixation with bone graft for Os subfibulare. Materials and Methods: Forty-two cases, which underwent anatomic reduction and bone graft for Os subfibulare from October 1998 to September 2004 were reviewed. We analysed preopertive symptoms and onset of symptoms and radiologically measured the size and amounts of displacement of Os subfibulare under the inversion stress. Postoperatively we evaluated the clinical results measured by Hasegawa method and evidence of union. Results: Preoperatively there were only pain around the lateral malleolus in 16 cases, only instability of ankle joint in 3 cases, and pain and instability in 23 cases. The age of symptom onset averaged 23 years(range, 13-38 years). Radiographically Os sufibulare anteriorly located from lateral malleolus were in 40 cases, posteriorly situated in 2 cases. The size of Os subfibulare ranged from $1{\times}4\;mm$ to $8{\times}17\;mm$. In 22 cases of inversion stress view, displacement of the Os sbufibulare averaged $1.5{\pm}1.1\;mm$ (0 to 5 mm). The postoperative clinical results were excellent in 41 cases, poor in 1 case. There were complications of 1 case of irritation of sural nerve, 1 case of nonunion. Conclusion: Anatomic reduction and bone graft is effective treatment method for symptomatic Os subfibulare.