• Journal of Korean Neurosurgical Society
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• v.62 no.6
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• pp.681-690
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• 2019

Objective : To determine whether the outcomes of percutaneous epidural neuroplasty (PEN) are influenced by the type of lumbar disc herniation (LDH) and evaluate the effectiveness of PEN in patients with single-level LDH. Methods : This study included 430 consecutive patients with single-level LDH who underwent PEN. Before treatment, the LDH type was categorized as bulging, protrusion, extrusion, and sequestration, while Pfirrmann grades were assigned according to imaging findings. Visual analog scale (VAS) scores for back and leg pain and success rates (Odom's criteria) were assessed at 1, 3, 6, and 12 months after treatment. Results : The mean preoperative VAS scores for back and leg pain were 6.90 and 4.23, respectively; these decreased after PEN as follows : 2.25 and 1.45, respectively, at 1 month; 2.61 and 1.68, respectively, at 3 months; 2.28 and 1.48, respectively, at 6 months; and 2.88 and 1.48, respectively, at 12 months (p<0.001). The decrease in VAS scores for leg pain was significantly greater in the extrusion and sequestration groups than in the other two groups (p<0.05); there were no other significant differences among groups. More than 70% patients exhibited good or excellent 12-month outcomes according to Odom's criteria. Subsequent surgery was required for 59 patients (13.7%), with a significantly higher rate in the extrusion (25.0%) and sequestration (30.0%) groups than in the bulging (7.3%) and protrusion (13.8%) groups (p<0.05). Nevertheless, subsequent surgery was not required for >70% patients with extrusion or sequestration. Patients with Pfirrmann grades 1-3 (14.0-21.5%) showed a significantly higher rate of subsequent surgery than those with Pfirrmann grade 0 (4.9%; p<0.05). Conclusion : Our findings suggest that PEN is an effective treatment for back and leg pain caused by single-level LDH, with the outcomes remaining unaffected by the LDH type.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.628-631
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• 2002

This paper has executed FE-analysis to review the feasibility for developing the process, which produces the narrow-cubic type cans, using the Backward Impact Extrusion process instead of using current process, multi-stage deep drawing. Proposes an analysis method by applying ALE(Arbitrary Lagrangian-Eulerian) description to non-axisymmetric extrusion. which is appreciated as one of good solution to mesh distortion in case of the large deformation plasticity process that has mass flux, and considers the factors which affects forming-loads related to punch velocity and fulid status of material.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.371-374
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• 2003

The bending process for the "ㄱ" section product can be developed by the hot metal extrusion machine with the two punches moving in the different velocity. The bending phenomenon can be controlled by difference of velocity at the die exit section by the different velocity of billets through the two-hole container. The results of the experiment show that "ㄱ" section product can be bended by the extrusion process and that the curvature of the product can be controlled by the velocity of punch and that the defects such as the distortion of section and the thickness change of the product and the folding and wrinkling of the product did not happen after the bending processing by the extrusion bending machine.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.05a
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• pp.9-19
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• 1999

A clad material is a different type of the typical composites which is composed of two or more materials joined at their interface surface. The advantage of clad material is that the combination of different materials can satisfy both the need of good mechanical properties and the other demand of user such as electrical properties instantaneouly. This paper is concerned with the direct and indirect extrusion process of copper-clad aluminum rod. Extrusion of copper-clad aluminum rod was simulated using a commercially available finite element package of DEFORM. The simulations were performed for copper-clad aluminum rod to predict the distributions of temperature, effective stress, effective strain rate and moan stress for some sheath thicknesses, die exit diameters and die temperatures.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.153-158
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• 2006

Nowadays, hollow upper-shaft of monobloc type has been considered for weight reduction and high quality in the automobile industry. To form the upper-shaft under tube cold extrusion, Taguchi method is applied to optimize the die design in this study. Taguchi method for optimum die design is to establish the optimal combination of design parameters and to reduce a number of experiments. Effect of parameters including the die relief, mandrel, die half angle is investigated and analyzed based on FEA analysis using a FEM commercial software MSC_Marc. Furthermore extrusion experiments have been performed to verify the results investigated in the FEM simulations.

• Transactions of Materials Processing
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• v.20 no.7
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• pp.485-490
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• 2011

The application of helical gears in crucial parts of automotive transmissions has been steadily increasing due to their higher power transfer performance compared to spur gears. However, the traditional gear manufacturing methods such as hobbing and deburring require large cycle times with expensive production lines so that there have been intensive efforts trying to manufacture gears via forging processes. Although forging processes for spur and bevel type gears have been developed on the practical level, the manufacturing of helical gears is still dependent on the traditional cutting process. Therefore, this paper seeks to develop a cold forward extrusion process for the helical gear with the pitch diameter of 43.5mm and a helix angle of $18.4^{\circ}$. A forward extrusion process was used due to the relatively small diameter of the target geometry. The material deforming behavior influenced by the die geometry was examined by using CAE analysis. Finally, it was found that the helical gear manufactured by the developed extrusion process satisfied the dimensional accuracy and mechanical characteristics for automotive transmissions.

• 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.

• the MEAT Journal
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• s.36 summer
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• pp.87-90
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• 2009

• Journal of Microbiology and Biotechnology
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• v.6 no.2
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• pp.147-149
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• 1996

Poly(3-hydroxybutyrate) (PHB) was synthesized and accumulated intracellularly to a high concentration (7 g/l) by cultivating recombinant Escherichia coli XL1-Blue (pSYLl05) in a complex medium containing 20 g/l glucose. The morphology of PHB granules was examined by transmission electron microscopy. The PHB granules synthesized in recombinant E. coli were much larger than reported values for wild type microorganisms, and were often irregularly shaped. Some cells were apparently extruding PHB into the medium, which suggests that PHB granules maintain some fluidity and cells become fragile due to PHB accumulation.

• Journal of the Korean Ceramic Society
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• v.27 no.1
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• pp.74-78
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• 1990

In this study, to develope the ultrasonic transducer element, the extrusion method which is the processing technique of the piezoelectric composite materials is introduced, the connectivity of the piezoelectric composite materials is the 1-3 type, and we study the properties of the materials. The electromechanical coupling factor(kt) of the materials is above 0.6, the resonance property(fr) is the thickness mode in the frequency range of 0.5 to 2 [MHz] and the acoustic impedance(Zac) is about 5 to 7 [Maryl]. From these results, it is known that the piezoelectric composite materials manufactured byt he extrusion method will be able to develope the ultrasonic transducer elements.