• Transactions of Materials Processing
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• v.24 no.1
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• pp.20-27
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• 2015

Hot tensile tests were conducted at different temperatures ranging from $20^{\circ}C$ to $550^{\circ}C$ to evaluate the mechanical properties of Al5052 seamless tubes. Such tubes can provide the technological foundation for complex forming using hot air bulging. Hot air bulging is one of the recently developed hydroforming techniques and it has some limitations in terms of cycle times. The benefits of hot air bulging are weight and cost savings through part consolidation and reduced post-forming processes such as welding and piercing. In order to extend the forming limits of Al lightweight material hot air bulging was investigated. A heated tube was placed in a heated die and sealed at the ends by sealing cylinders. The heated tube was subsequently expanded against the die cavity wall by internal pressure using air medium. The results of the current study show that axial feeding speed and air pressure have an effect on the formability of Al tubes during air bulging at elevated temperatures.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.7
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• pp.1842-1849
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• 1996

This paper presents a full-wave, moment method analysis of a Moreno directional coupler with tow crossed-slots between two crossed rectangular waveguides. the overall structure is divided into several rectangular waveguides and cavities by the use of the equivalence principle to the complex slot regions. this enables a simple and efficient analysis involving the well-known retangular waveguide/cavity Green's functions. For a numerically efficient simulation, the roof-top basis expansion and line testing is used and an acceleration technique is applied to the series summation in the Green's functions. The numerical results are compared with the measurements to verify the correctness of the present analysis.

• Journal of the Optical Society of Korea
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• v.11 no.3
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• pp.85-92
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• 2007

In the past, precision optical glass lenses were produced through multiple processes such as grinding and polishing, but mass production of aspheric glass lenses requiring high accuracy and having complex profile was rather difficult. In such a background, the high-precision optical glass molding pressing (GMP) process was developed with an eye to mass production of precision optical glass parts by molding press. In this paper, as a fundamental research to develop the multi-cavity mold for higher productivity of a progressive GMP process used in the fabrication of an aspheric glass lens, an aspheric glass lens forming simulation was carried out.

• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.2
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• pp.9-17
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• 2002

For turbulent spray combustion flows a coupled numerical procedure was developed, This method was discretized by using generalized curvilinear coordinates to handle complex geometries. The preconditioning and eigenvalue rescaling techniques were employed to provide efficient convergences over a wide range of subsonic Mach numbers. The accuracy was validated by simulating the laminar cavity flow. The film cooling effect of a liquid rocket engine (KSR-III) were investigated by a spray combustion analysis. The film cooling showed a negative effect on the combustion efficiency. In the combustion chamber wall, the film cooling effect was revealed to be promoted by the production of fuel rich zone.

• Archives of Pharmacal Research
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• v.10 no.2
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• pp.69-74
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• 1987

The characteristics of zipeprol-$\beta$-cyclodextrin system were studied by circular dichroism, competitive UV method and dialysis method. In this experiment, binding constants by competitive UV method, circular dichroism and dialysis method were 155 M$^{-1}$ 187 M$\^{-1}$/($\pm$ 5%) and 315 $^{-1}$, repectively. It shows that zipeprol forms 1:1 compelx with $\beta$-cyclodextrin by circular dichroism and 1:2 by dialysis method. pH profile shows that binding force seems to be a hydrophobic interaction. It is suggested that benzene ring be accomodated in the cavity of $\beta$-cyclodextrin.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.33-33
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• 1999

The design of a vacuum pumping system for the KOMAC (Korea Multipurpose Accelerator Complex) RFQ(Radio-Frequency Quadrupole) linac is described. [Fig] Resulted from the lost proton beam, gas streaming from the LEBT (Low Energy Beam Transport) and out-gassing from the surfaces of the RFQ cavity and vacuum plumbing, the total gas load will be on the order of 7.2$\times$10-4 Torr-liters/sec, consisting mainly of hydrogen. The system designed to pump on a continual basis with redundancy to ensure that the minimal operating vacuum level of 1.0$\times$10-6 Torr is maintained even under abnormal conditions. Details of the design, performance analysis and the preliminary test results of the cryogenic pumps are presented.

• Journal of Sensor Science and Technology
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• v.32 no.4
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• pp.252-256
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• 2023

A one-step method for nanoscale patterning of silver ionic ink on a substrate is developed using a microscale, elastic mold deformation. This method yields unique micro/nanoscale metallic structures that differ from those produced using the original molds. The linewidth of these metallic structures is significantly reduced (approximately 10 times) through the sidewall deformation of the original mold cavity on a thin liquid film, as verified by finite element analysis. The process facilitates the fabrication of various, isolated and complex micro/nanoscale metallic structures with negligible residual layers at low cost and high throughput. These structures can be utilized for various applications, including optoelectronics, wearable sensors, and metaverse-related devices. Our approach offers a promising tool for manipulation and fabrication of micro/nanoscale structures of various functional materials.

• Journal of Pharmaceutical Investigation
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• v.24 no.2
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• pp.95-104
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• 1994

Inclusion complexes of ketoconazole(KT) with ${\alpha}^_$, ${\beta}^_$cyclodextrin(CD) and $dimethy1-{\beta}-cyclodextrin$ (CD) and $dimethy1-{\beta}-cyclodextrin(DM{\beta}CD)$ as nasal absorption enhancer were prepared in 1: 2 molar ratios by freeze-drying and solvent evaporation methods. In order to compare with the intrinsic absorptivity of KT in the jejunum(J) and the nasal cavity(N), the in situ simultaneous perfusion method was employed. The in situ recirculation study revealed that KT-CD inclusion complexes with the greater stability constant and the faster dissolution rate proportionally increased the absorption of KT in the J and N of rats. The rank order of apparent KT permeability$(P_{app}\;:\;cm/sec\;{\time}\;1O^{-5}{\pm}S.E.)$, corrected by surface area of absorption, was $5.10{\pm}0.3(N,\; KT-DM{\beta}CD)$ )> $4.13{\pm}0.4(N,\;KT-{\beta}-CD)$ )> $3.52{\pm}0.2(N,\;KT-{\alpha}-CD)$ )> $2.76{\pm}0.3(J,\; KT-DM{\beta}CD)$ )> $2.61{\pm}0.5(J,\;KT-{\beta}-CD)$ )> $2.42{\pm}0.4(J,\;KT-{\alpha}-CD)$ at pH 4.0. The in crease in permeability of $KT-DM{\beta}CD$ inclusion complex was 2.6 folds in the J and 4.5 folds in the N when the perfusing solution was changed from the buffer(pH 4.0) to saline. The absorption rate of $KT-DM{\beta}CD$ inclusion complex after nasal administration was more rapid than those of ketoconazole alone and $KT-DM{\beta}CD$ inclusion complex after oral administration to rats. In comparision with an oral administration of ketoconazole suspension in corn oil, the relative bioavailability was calculated 137.3% for the oral and 195.0% for nasal $KT-DM{\beta}CD$ inclusion complex in rats. The present results suggest that $KT-DM{\beta}CD$ inclusion complex may serve as a potential nasal absorption enhancer for the nasal delivery of ketoconazole.

• The Korean Journal of Cytopathology
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• v.9 no.1
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• pp.15-20
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• 1998

Mutant form of the p53 gene product is abnormally accumulated in the nuclei of the tumor cells due to prolonged half life, and readily detected by immunohistochemical methods. To determine the positivity rate of p53 in body cavity fluid according the primary site and histological types of tumors and the utility of p53 immunostaining as an adjunct in the diagnosis of malignancy, we reviewed 69 effusions, including pleural effusion, ascitic fluid, and pericardial fluid, that were diagnosed as overt malignancy and 21 effusions of suspicious malignancy, immunohistochemistry was performed on paraffin-embedded cell blocks using a monoclonal antibody to p53 supressor gene product(Clone DO7) and a standard avidin-biotin complex technique with a citrate buffer antigen retrieval solution. The results were as follows; of the 46 pleural effusions with overt malignancy, 22 were immunopositive for p53 protein; of the 21 ascitic fluids with overt malignancy, 5 were positive for p53. Positivity rates according to the primary sites of tumors were 18 of 34(52.9%), 8 of 21(38.1%), 1 of 9(11.1%) cases of the tumors of the lung, GI tract, and ovary, respectively. According to the histologic types of lung cancer, 11 cases(61.6%) were positive out of 18 adenocarcinomas, 2 of 5 large cell undifferentiated carcinomas, and 1 of 2 small cell undifferentiated carcinomas. Of 21 cases of suspicious malignancy, 6 were positive for p53 and all of them(6/6) were confirmed as adenocarcinoma of the lung or GI tract. These findings indicate that p53 immunostaining using paraffin embedded cell block is useful diagnostic and prognostic marker in body fluid cytology although negative immunostaining does not exclude malignancy.

• Journal of Biomedical Engineering Research
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• v.19 no.4
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• pp.423-429
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• 1998

Human pharynx is unique, acting as a complex interchange between the oral cavity and esophagus, and between the nasal cavity and lungs. It is actively involved in the transport of food and liquid, producing the forces that guide that bolus into the upper esophagus and away from the adjacent larynx and lungs. This study intended to develop a biomechanical model of the human pharynx, utilizing Finite Element Method(FEM). Within each model changes in cross sectional intralumenal area were calculated and compared with the area from the computer-generated FE model. Area matching allowed estimation of intraluminal pressure gradients during swallow. The estimated pharyngeal pressure gradient varies from one region to another. The estimated pharyngeal pressure gradients showed different patterns for upper four levels and lower four levels. The contraction velocity for upper four levels is much higher than lower four levels. The higher contraction velocities and pressure gradients in the upper levels are consistent with the bolus velocities required for efficient swallow.