• Transactions of Materials Processing
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• v.8 no.3
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• pp.284-293
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• 1999

The rigid-plastic finite element analysis requires a large amount of computation time due to its non-linearity. For economic computation, mismatching refinement, and efficient domain decomposition method with different mesh density for each sub domain, is developed. A modified velocity alternating scheme for the interface treatment is proposed in order to obtain good convergence and accuracy. As a numerical example, the axisymmetric extrusion process is analyzed. The results are discussed for the various velocity update schemes form the viewpoint of convergence and accuracy. The three-dimen-sional extrusion process with rectangular section is analyzed in order to verify the effectiveness of the proposed method. Comparing the results with those of the conventional method of full region analysis, the accuracy and the computational efficiency of the proposed method are then discussed.

• Preventive Nutrition and Food Science
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• v.2 no.4
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• pp.296-300
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• 1997

Glucose syrup and lactose, mixed with citric acid as a polymerizing catalyst, was processed using twin screw extruder, in which 40 of L/D(length/diameter) ratio was designed to provide sufficient retention in extruder for polymerization of sugars. The polymerization yields of glucose syrup were 36.90%, 55.44% and 77.10% at 160, 180 and 20$0^{\circ}C$, respectively, while those of lactose were 26.45%, 38.16% and 45.86% at the same temperatures. Gel permeation chromatography exhibited that the higher molecular weight fractions were increased with extrusion temperature, which also led to increasing hydrodynamic intrinsic viscosity. Both uco-oligosaccharides and lacto-oligosaccharides produced by extrusion of glucose syrup and lactose were stable for thermal treatments over a wide range of pH3.0~11.0. In addition, $\alpha$-amylase and amyloglucosidase treatment of gluco-oligosaccharides did not affect the solution viscosity, indicating the random linkage rather than $\alpha$-1, 4 linkages of glucose and thus the potential applications as a dietary fiber. In this research it was clearly observed that twin screw extrusion can be successfully utilized to produce gluco-oligosaccharides and lacto-oligosaccharides rapidly and continuously in conjunction with selective control of polymerized composition.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.11
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• pp.1010-1015
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• 2008

In this study, the characteristics of aluminum tube hydroformed products at different extrusion type and heat treatment conditions were investigated. For the investigation, as-extruded, full annealed and T6-treated Al 6061 tubes at different extrusion type were prepared. To evaluate the hydroformability, free bulge test was performed at room temperature to $300^{\circ}C$. Also mechanical properties of hydroformed products at various pre- and post-heat treatments were estimated by hexagonal prototype hydroforming test at $250^{\circ}C$. And the tensile test specimens were obtained from hexagonal prototype hydroformed tube. As a results, hydroformability of full annealed tube is $5{\sim}8%$ higher than that of extruded and T6-treated tube. The tensile strength and elongation of T6-post heat treated indirect extrusion tube were more than 330MPa and 12%, respectively. However, T6 pre treated hydroformed product represents high strength, 330MPa and low elongation, 8%. Therefore, Hydroformability of Al6061 tube showed similar value for both extrusion types. However flow stress of direct tube showed $20{\sim}50MPa$ lower value than indirect tube.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.28 no.3
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• pp.114-125
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• 2015

Objectives : The objective of this study was to evaluate the effect of Herbal medicine, extrusion and Hwangryunhaedok-tang Pharmacopuncture therapy for treating Sil-Yol(Excess heat) type acne.Methods : Total of 22 patients with Sil-Yol(Excess heat) type acne were treated with the Herbal medicine(Chungsangbangpoong-tang, Yangkyuksanwha-tang, Hwalhyeolsano-tang, Galgeunhaegi-tang, Daeshihotang) and weekly Hwangryunhaedok-tang Pharmacopuncture & extrusion therpay. By the standardized photography before and after treatment, KASG and survey for patient`s satisfaction, we checked effect of Herbal medicine and Hwangryunhaedok-tang Pharmacopuncture therapy for treating acne.Results : 1. In 22 patients who underwent the Herbal medicine, extrusion and Hwangryunhaedok-tang Pharmacopuncture therapy, there was an significant improvement in KASG. Mean value of KAGS before treatment is 3.59±0.80, mean value of KAGS after treatment is 1.95±65.2. The responses to the survey for satisfaction revealed that 5 patients were very satisfied with their outcomes, 11 patients were satisfied, 5 patients were somewhat satisfied, 1 patient was dissatisfied.Conclusion : In Korean medicine, Herbal medicine and Hwangryunhaedok-tang Pharmacopuncture therpay might be effective method for treating Sil-Yol(Excess heat) type acne.

• Journal of the Korean Society for Heat Treatment
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• v.26 no.4
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• pp.165-172
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• 2013

In the present study, the microstructure and solution treatment response of Al-Zn-Mg alloys bars by thixo-extrusion was investigated. The alloy bars were solution treated at 400, 430, 460 and $490^{\circ}C$ for various times. In order to examine the microstructures and phase analysis of the samples after solution treatment, it was performed by optical and scanning electron microscopy. And, Vickers hardness and electrical conductivity was measured on the solution treated samples for each condition to investigate the solution treatment response of extruded bars during solution treatment. The results show that the optimum solution heat treatment conditions of thixo-extruded Al-Zn-Mg alloy for minimization of the grain growth and degradation promotion of the second phase is a temperature of $460^{\circ}C$ and holding time of 0.5 to 2 h.

• Journal of the Korean Society for Heat Treatment
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• v.32 no.2
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• pp.68-73
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• 2019

${\alpha}$-titanium alloy has a relatively low heat treatment characteristic and it is mainly subjected to heat treatment for residual stress, recovery or dynamic recrystallization. In this study, commercially pure titanium hollow castings was fabricated by gravity casting. Heat treatments were carried out at $750^{\circ}C$, $850^{\circ}C$ and $950^{\circ}C$ to investigate the effect of post-heat treatment on microstructure and mechanical properties. Beta-transus temperature ($T_{\beta}$) was about $913^{\circ}C$, and equiaxed microstructure was shown at temperature below $T_{\beta}$ and lath-type microstructure at temperature above $T_{\beta}$. Microstructure and mechanical properties did not show any significant difference in the direction of solidification for titanium hollow billet, so it can be seen that it was a well-made material for extrusion process. The optimum heat treatment condition of hollow billet castings for the seamless tube production was $850^{\circ}C$, 4 hr, FC, indicating a combination of equiaxed microstructure and appropriate mechanical properties.

• The Journal of Korean Obstetrics and Gynecology
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• v.19 no.1
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• pp.97-110
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• 2006

Purpose : To address the ability of Myrrha (MY) to induce cell death, we investigated the effect of MY on apoptosis. In human cervical carcinoma HeLa cells, apoptosis occurred following MY exposure in a dose-dependent manner. Methods : We have tested several kinds of anti-oxidants to investigate the MY-induced apoptotic mechanism. Among the anti-oxidants, N-acetyl cysteine(NAC) or reduced glutathione (GSH) protects MY-induced apoptosis. NAC is an aminothiol and synthetic precursor of intracellular cysteine and GSH. To confirm the role of GSH in MY-induced apoptosis, methionine and cystathionine-glutathione extrusion inhibitors were treated in the presence of MY. Results : NAC, GSH, methionine or cystathionine led to protective effect against MY-induced apoptosis in HeLa cells. The GSH and GSH-associated reagents regulate MY-induced cytochrome c release and the resultant caspase-3 activation. Furthermore, the two specific inhibitors of carrier-mediated GSH extrusion, methionine and cystathionine demonstrate GSH extrusion occurs via a specific mechanism. While decreasing GSH extrusion and protecting against MY-induced apoptosis, methionine and cystathionine failed to exert anti-apoptotic activity in cells previously deprived of GSH. Conclusion : the target of the protection is indeed GSH extrusion. This shows that the protective effect is achieved by forcing GSH to stay within the cells during apoptogenic treatment. All this evidence indicates the extrusion of GSH precedes andis responsible for the apoptosis, probably by altering the intracellular redox state, thus giving a rationale for the development of redox-dependent apoptosis in MY-treated human cervical carcinoma HeLa cells.

• Korean Journal of Medicinal Crop Science
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• v.17 no.6
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• pp.379-387
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• 2009

The aim of this investigation was to examine the influence of extrusion on dietary fiber profile and the content of bioactive compounds, rutin and quercetin in young sprout, whole seed, and matured stem of Tartary buckwheat. WSI(water soluble index) is increased by a function of both screw profile and process temperature, compared to control in different parts of Buckwheat. Also, WSI of ME is increased more than 5.2 times in grain, compared to that of control. The effect of precooking by extrusion on the dietary fiber profile of buckwheat flour was evaluated. Precooking by extrusion significantly increased SDF in flour, although in most cases extrusion decrease in TDF a little. The thermo-mechanical treatment undergone by the buckwheat flour during extrusion led to redistribute part IDF fraction to SDF, leading to an increase in the latter. The content of rutin was increased about two fold in extruded flour of sprout, compared to in control. This increase maybe why these compounds are released from cell wall by high shear processing under high temperature.

• Transactions of Materials Processing
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• v.32 no.6
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• pp.344-351
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• 2023

The use of Zn-Al-Mg alloy coatings for enhancing the corrosion resistance of steel sheets is gaining prominence over traditional Zn coatings. There is a growing demand for the development of thermal spray wires made from Zn-Al-Mg alloys, as a replacement for the existing wires produced using Al and Zn. This is particularly crucial to secure corrosion resistance and durability in the damaged areas of coated steel sheets caused by deformation and welding. This study focuses on the casting and extrusion processes of Zn-2Al-1Mg alloy for the fabrication of such spray wires and analyzes the changes in microstructure during the extrusion process. The Zn-2Al-1Mg alloy, cast in molds, was subjected to a heat treatment at 250 ℃ for 3 hours prior to extrusion. The extrusion process was carried out by heating both the material and the mold up to 300 ℃. Microstructural analysis was conducted using FE-SEM and EDS to differentiate each phase. The mechanical properties of the cast specimen were evaluated through compression tests at temperatures ranging from 200 to 300 ℃, with strain rates of 0.1 to 5 sec^-1. Vickers hardness testing was utilized to assess the inhomogeneity of mechanical properties in the radial direction of the extruded material. Finite Element Analysis (FEA) was employed to understand the inhomogeneity in stress and strain distribution during extrusion, which aids in understanding the impact of heterogeneous deformation on the microstructure during the process.

• The Journal of Churna Manual Medicine for Spine and Nerves
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• v.5 no.1
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• pp.101-110
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• 2010

Objectives: The propose of this study is to find out the clinical application of conservative treatment to 3 patients who has Disc Extrusion on L-spine MRI Methods: We examined 3 patients with Lumbar Intervertebral Disc Herniation (HIVD of L-spine) with Disc Extrusion who showed changes on MRI images before/after the treatment among HIVD of L-spine patients who visited Jaseng Hospital of Oriental Medicine. Results: In this study, the first MRI examination of HIVD of L-spine patients was performed at the first visit and re-examination of MRI was done after the treatment. In each case, the size of the extruded disc was considerably reduced in MRI image. Low back and leg pain was also reduced significantly after conervative oriental medical treatment. Conclusions: Conservative oriental medical treatment can be effective for improving symptoms of HIVD, decreasing pain, also decreasing the volume of herniated disc.