• Tuberculosis and Respiratory Diseases
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• 제42권6호
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• pp.801-812
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• 1995

CR asthma is associated with disease chronicity, a positive family history of asthma and in vitro and in vivo defects in mononuclear cell function. The HPA axis in CR asthmatics is suppressed normally by dexamethasone and the pharmacokinetic profile of an oral dose of prednisolone is similar to that found in CS subjects. In addition, competitive binding studies have shown that the ligand binding and nuclear translocation functions of the GR are similar in the two groups. Studies using gel retardation assay have indicated a defect in DNA binding in CR subjects. Chemical mutational analysis of the GR has shown that is not due to a defect in its structure at the cDNA level. Scatchard analysis of the GR/DNA and GR/ligand interactions suggests that there may be transcriptional interference of the GR with other transcriptionally active molecules leading to defective gene transcription.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.437-438
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• 2006

Generally, the vertical roll process is used to achieve extensive width reduction in hot strip mill. However, it is difficult to avoid the defects such as dog-bone and seam-defect. The sizing press has been developed in response to the defects mentioned above. Especially, this study is carried out to investigate the deformation of slab by two-step sizing press. The deformation behavior in the width sizing process is more favorable than that in conventional vertical rolling edger. The objective of this study is to determine the optimal anvil shape parameters in the sizing press with two-step die from the viewpoint of edge-seam length. In general, the edge-seam defect occurs parallel to the rolling direction at both edges in horizontal rolling process after sizing press. The optimal combination of the parameters is determined by FE-simulation and Artificial Neural Network (ANN). The slab deformation in sizing press with convex anvil is analyzed by FE-simulation. The most suitable profile of the anvil is also discussed fur the improvement of trimming loss because of the side seam defect by FE-simulation and ANN.

• Journal of Welding and Joining
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• 제35권3호
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• pp.35-43
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• 2017

A 3D transient heat transfer model is developed by ABAQUS software to study the temperature distribution during friction stir welding process at different rotational speeds. Furthermore, AA 5083-O plates were joined by FSW technique. For this purpose, a universal milling machine was used to perform the welding process and a mechanical vice was used to fix the work pieces in the proper position. The joints were friction stir welded at a constant travel speed 50 mm/min and two rotational speed values; 400 rpm and 630 rpm using two types of tools; cylindrical threaded pin and tapered smooth one. At each welding condition the temperature was measured using infra-red thermal image camera to verify the simulated temperature distribution. The welded joints were visually inspected as well as by macro- and microstructure evolutions. In addition, the welded joints were mechanically tested for hardness and tensile strength. The maximum peak temperature obtained was at higher rotational speed using the threaded tool pin profile. The results showed that the rotational speed affects the peak temperature, defects formation and sizes, and the mechanical properties of friction stir welded joints. Moreover, the threaded tool gives superior mechanical properties than the tapered one at lower rotational speed.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.457-458
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• 2012

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.242-246
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• 1996

Accurate measurements of burr profile and burr size are very important for the automation of deburring. In this paper, a new burr measurement system using capacitance sensor is proposed. Ultra precision milling machine was used as a sensor positioning system. The possibility and limitation of employing a capacitance sensor to defect burrs are also investigated. The proposed system is proven to be relatively accurate, easy to setup and lower cost. This system will be applicable to a fully automated deburring system with minor modifications.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(II)
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• pp.1086-1093
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• 2002

In Korea mid chord offset method has been used to measure the track irregularities. This method has been also used all over the world widely because of its accessibility and the operational excellence for measured data. But it has been pointed out recently that track irregularities reconstructed from measured data have unexpected noise in the high frequency area as the defect of this way. This study shows the cause of noise which occurs during reconstructing process and mentions the solutions briefly.

• Journal of Periodontal and Implant Science
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• 제44권3호
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• pp.147-155
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• 2014

Purpose: In the anterior maxilla, hard and soft tissue augmentations are sometimes required to meet esthetic and functional demands. In such cases, primary soft tissue closure after bone grafting procedures is indispensable for a successful outcome. This report describes a simple method for soft tissue coverage of a guided bone regeneration (GBR) site using the double-rotated palatal subepithelial connective tissue graft (RPSCTG) technique for a maxillary anterior defect. Methods: We present a 60-year-old man with a defect in the anterior maxilla requiring hard and soft tissue augmentations. The bone graft materials were filled above the alveolar defect and a titanium-reinforced nonresorbable membrane was placed to cover the graft materials. We used the RPSCTG technique to achieve primary soft tissue closure over the graft materials and the barrier membrane. Additional soft tissue augmentation using a contralateral RPSCTG and membrane removal were simultaneously performed 7 weeks after the stage 1 surgery to establish more abundant soft tissue architecture. Results: Flap necrosis occurred after the stage 1 surgery. Signs of infection or suppuration were not observed in the donor or recipient sites after the stage 2 surgery. These procedures enhanced the alveolar ridge volume, increased the amount of keratinized tissue, and improved the esthetic profile for restorative treatment. Conclusions: The use of RPSCTG could assist the soft tissue closure of the GBR sites because it provides sufficient soft tissue thickness, an ample vascular supply, protection of anatomical structures, and patient comfort. The treatment outcome was acceptable, despite membrane exposure, and the RPSCTG allowed for vitalization and harmonization with the recipient tissue.

• 한국컴퓨터정보학회논문지
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• 제17권6호
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• pp.101-109
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• 2012

고 품질의 소프트웨어를 개발하기 위해서는 소프트웨어 내에 잠재된 결점을 제거하기 위한 품질관리계획이 요구된다. 이를 위해 결점 제거 프로필을 적절히 기술해야만 한다. 기존의 유조와 도관 모델은 결점이 제거되고 도피하는 결점을 계산하는데 복잡한 과정을 수행한다. 또한 어느 단계에서 삽입된 결점이 제거되고 도피하였으며, 단계별 결점 발견율이 얼마인지를 상세히 알고 있어야만 한다. 이러한 복잡한 과정을 단순화하기위해 본 논문은 결점필터링 개념에 기반하여 모델을 제시하였다. 제시된 모델은 임의의 단계에서 제거와 도피한 결점이 어느 단계에서 삽입된 결점에 관련되어 있는지 고려할 필요가 없어 결점을 보다 간략히 기술할 수 있는 장점이 있다. 또한, 결점 제거 품질척도와 생산성 척도의 함수에 기반하여 결점제거에 요구되는 노력 추정 모델을 제시하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.420-420
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• 2013

We investigated oxygen plasma effect on defect states near the interface of AlGaN/GaN High Electron Mobility Transistor (HEMT) structure grown on a silicon substrate. After the plasma treatment, electrical properties were evaluated using a frequency dependant Capacitance-Voltage (C-V) and a temperature dependant C-V measurements, and a deep level transient spectroscopy (DLTS) method to study the change of defect densities. In the depth profile resulted from the temperature dependant C-V, a sudden decrease in the carrier concentration for two-dimensional electron gas (2DEG) nearby 250 K was observed. In C-V measurement, the interface states were improved in case of the oxygen-plasma treated samples, whereas the interface was degraded in case of the nitrogen-plasma treated sample. In the DLTS measurement, it was observed the two kinds of defects well known in AlGaN/GaN structure grown on sapphire substrate, which have the activation energies of 0.15 eV, 0.25 eV below the conduction band. We speculate that this defect state in AlGaN/GaN on the silicon substrate is caused from the decrease in 2DEG's carrier concentrations. We compared the various DLTS signals with filling pulse times to identify the characteristics of the newly found defect. In the filling pulse time range under the 80 us, the activation energies changed as the potential barrier model. On the other hand, in the filling pulse time range above the 80 us, the activation energies changed as the extended potential model. Therefore, we suggest that the found defect in the AlGaN/GaN/Si structure could be the extended defect related with AlGa/N/GaN interface states.

• Archives of Plastic Surgery
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• 제40권5호
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• pp.564-569
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• 2013

Background Scalp defects may be caused by various etiological factors, and they represent a significant surgical and aesthetic concern. Various surgical techniques can be applied for reconstructive work such as primary closure, skin grafting, pedicled or free flaps. In this article, the authors share their clinical experience with scalp operations using the technique of local flaps and discuss the application of this method from the perspective of not only the size of the defect, but also in relation to the anatomical area, quality of surrounding tissue, and patient's condition. Methods During the period from December 2007 to December 2012, 13 patients with various scalp defects, aged 11 to 86 years, underwent reconstruction with local pedicle flaps. The indications were based on the patients' condition (age, sex, quality of surrounding tissue, and comorbidities) and wound parameters. Depending on the size of the defects, they were classified into three groups as follows: large, 20 to 50 $cm^2$; very large, 50 to 100 $cm^2$; extremely large, 100 $cm^2$. The location was defined as peripheral (frontal, temporal, occipital), central, or combined (more than one area). We performed reconstruction with 11 single transposition flaps and 1 bipedicle with a skin graft on the donor area, and 2 advancement flaps in 1 patient. Results In all of the patients, complete tissue coverage was achieved. The recovery was relatively quick, without hematoma, seroma, or infections. The flaps survived entirely. Conclusions Local flaps are widely used in scalp reconstruction since they provide healthy, stable, hair-bearing tissue and require a short healing time for the patients.