• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.1
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• pp.61-70
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• 2005

This study investigated the spinal loads(L5/S1 disc compression and shear forces) predicted from four biomechanical models: one EMG model and three optimization models. Three objective functions used in the optimization models were to miminize 1) the cubed muscle forces : MF3, 2) the cubed muscle stress : MS3, 3) maximum muscle intensity : MI. Twelve healthy male subjects participated in the isometric voluntary exertion tests to six directions : flexion/extension, left/right lateral bending, clockwise/ counterclockwise twist. EMG signals were measured from ten trunk muscles and spinal loads were assessed at 10, 20, 30, 40, 50, 60, 70, 80, 90%MVE(maximum voluntary exertion) in each direction. Three optimization models predicted lower L5/S1 disc compression forces than the EMG model, on average, by 31%(MF3), 27%(MS3), 8%(MI). Especially, in twist and extension, the differences were relatively large. Anterior-posterior shear forces predicted from optimization models were lower, on average, by 27%(MF3), 21%(MS3), 9%(MI) than by the EMG model, especially in flexion(MF3 : 45%, MS3 : 40%, MI : 35%). Lateral shear forces were predicted far less than anterior-posterior shear forces(total average = 124 N), and the optimization models predicted larger values than the EMG model on average. These results indicated that the optimization models could underestimate compression forces during twisting and extension, and anterior-posterior shear forces during flexion. Thus, future research should address the antagonistic coactivation, one major reason of the difference between optimization models and the EMG model, in the optimization models.

• Textile Coloration and Finishing
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• v.10 no.5
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• pp.1-12
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• 1998

This study surveys the mechanical properties such as bending and shear properties to the weight reduction rate of PET fabrics. For this purpose, 12 kinds of satin and 18 kinds of plain weave fabrics are prepared with change of the physical properties of weft yarn(T.P.M., density, and denier) The weight reduction rate was 0％, 12％, 25％, and 30％. Bending rigidity and hysteresis, shear rigidity and hysteresis were measured and discussed with theoretical values in relation with weft twist, yarn linear density, weft fabric density and weave structures.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1993.11a
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• pp.43-46
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• 1993

Superconducting cable (Ic: 60 A at 77K. 10 filaments) with Bi high-Tc superconducting system was developed by powder - in - tube method. Pressing and sintering process of the cables were repeated for growth of 2223 high-Tc superconducting phase. The cable can be fabricate by twist method that is nessary for high current density and cooled circulative system. This cab1e system can be used for commercial.

• Journal of the Chungcheong Mathematical Society
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• v.18 no.1
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• pp.65-72
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• 2005

In this paper we will introduce all types of the isotwist foldings of a manifold M into itself. The limits of the isotwist foldings of a manifold are obtained. Also the relations between conditional retraction and this type of the folding are achieved. Finally the variant and invariant of the immersion under the type of folding are deduced.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.301-302
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• 2003

원사제조 이후의 공정인 원사가공 기술은 다양한 기술개발에 의해 발전되어 왔다. 원사가공 기술은 합성섬유의 강도, 내구성 등의 기능성을 유지하면서 광택, 촉감 둥의 단점을 보완하기 위해 개발이 진행중이고, 그 중 가연공정은 합성섬유의 벌키성 및 신축성의 향상과 직물의 Handle을 개선하기 위한 것으로 Pin type DTY, Belt type DTY, Disk type DTY 등의 다양한 형태로 가공되고 있다(1). (중략)

• Kyungpook Mathematical Journal
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• v.46 no.1
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• pp.139-144
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• 2006

In this paper, we will introduce the isotwist foldings of a manifold M into itself. The limits of the isotwist foldings of a manifold are obtained. Also the relations be-tween conditional retraction and this type of the foldings are achieved. Finally the variant and invariant of the immersion under this type of foldings are deduced.

• Journal of Korean Neurosurgical Society
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• v.52 no.2
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• pp.133-137
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• 2012

Objective : Twist-drill craniostomy (TDC) with closed-system drainage and burr-hole drainage (BHD) with a closed system are effective treatment options for chronic subdural hematoma (CSDH). The aim of this study was to analyze clinical data and surgical results from symptomatic CSDH patients who underwent TDC with closed-system drainage at the pre-coronal point (PCP). Methods : We analyzed data for 134 symptomatic CSDH patients who underwent TDC at the PCP with closed-system drainage. We defined the PCP for TDC to be 1 cm anterior to the coronal suture at the level of superior temporal line. TDC at the PCP with closed-system drainage was selected in patients with CSDH that extended beyond the coronal suture, confirmed by preoperative CT scans. Medical records, radiological findings, and clinical performance were reviewed retrospectively. Results : Of the 134 CSDH patients, 114 (85.1%) showed improved clinical performance and imaging findings after surgery. Catheter failures were seen in two cases (1.4%); the catheters were inserted in the epidural space. Recurrent cases were seen in eight patients (5.6%), and they were improved with a second BHD with a closed-system operation. Conclusion : TDC at the PCP with closed-system drainage is safe and effective for patients with symptomatic CSDH whose hematomas extend beyond the coronal suture.

• Fashion & Textile Research Journal
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• v.25 no.5
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• pp.651-660
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• 2023

This study aimed to research the local production of conductive composite yarn, a source material used in textile-type electrodes and circuits. The physical properties of an internationally available conductive composite yarn were analyzed. To manufacture the conductive composite yarn, we selected one type of conductive yarn with Ag-coated polyamide of 150d 1 ply, along with two types of polyethylene terephthalate (PET) with circular and triangular cross-sections, both with 150d 1 ply. The conductive composite yarn samples were manufactured at 250, 500, 750, and 1000 turns per meter (TPM). For both conductive composite yarn samples manufactured from two types of PET filaments, the twist contraction rate of the sample with a triangular cross-section was stable. Among the samples, the tensile strength of the sample manufactured at 750 TPM was the highest at approximately 4.1gf/d; the overall linear resistance was approximately 5.0 Ω/cm, which is within the target range. It was confirmed that the triangular cross-section sample manufactured with 750 TPM had a similar linear resistance value to the advanced product despite the increase in the number of twists. In future studies, we plan tomanufacture samples by varying the twist conditions to derive the optimal conductive yarn suitable for smartwear and smart textile manufacturing conditions.

• Textile Coloration and Finishing
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• v.18 no.1
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• pp.33-43
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• 2006

The purpose of this study was to eximine the effect of different yam twisting methods on mechanical properties and 3D CAD images of plain knitted fabrics made of composite yarns. Six yams were used in this study: four different composite yams of the six consist of acetate and functional polyester (Poly-m) with the ratio of 70:30, and the rest two are the original acetate $100\%$ yam and the poly-m $100\%$ yarn. The four kinds of composite yarns were processed in combinations of twisting processes such as interlacing, false twisting, two for one twisting, combined twisting and single covering, and the two original yams were knitted without any twisting process. Sixteen mechanical properties of all the six knitted fabrics, knitted under the same knitting conditions, were measured by KES-FB system with the outer knit condition. The results were as follows; 1) When the sample applied with the false twisting process at the temperature as high as $220^{\circ}C$, ENT, B, HB, G and RC values of samples increased which leads to increasing dimensional stability. 2) To gain the high bending and shear properties in the single covering process, selecting the core yarn with such properties is the most important factor. 3) Interlacing process effected to increase RC value. 4) False twisting process after interlacing process gave bulkiness and un-interlaced part in yam was increased SMD value. The SMD value of the kilted fabric of the composite yarn, which was put through the combined twist process, was higher than those of which simple process such as the two for one twist or the single covering process applied. In order to achieve the silk-like surface feel of knitted fabric, the sin91e covering process is recommended. 5) Examining the simulation images of the knifed fabrics of composite yarn, which were generated by the 3D CAD system based on the mechanical properties of the fabric, led that appearance could be changed as different twisting methods were applied.

• Journal of Korean Neurosurgical Society
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• v.37 no.4
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• pp.282-286
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• 2005

Objective: Symptomatic chronic subdural hematoma(CSDH) is a well-known neurosurgical entity and most of the lesion is managed by surgical treatment. The authors analyze the surgical indication and the treatment results of twist drill craniostomy with closed-system drainage(TDD) for the symptomatic CSDH. Methods: From March 2001 through December 2003, 31 patients who were treated with TDD for the symptomatic CSDH and followed more than 6months were included. The radiologic criteria of TDD in this study were 1) homogeneous density of hematoma on computed tomography(CT), 2) no septation of hematoma on magnetic resonance imaging(MRI), and 3) thicker hematoma more than twice thickness of skull. Surgical procedures were performed on the maximum thickness of hematoma on CT/MRI. Short and long Steinman pins were used to penetrate the skull and hematoma membrane. As the 5L catheter was inserted through the drill hole, it was kept for 1 - 7days for the drainage of CSDH. The patients of CSDH were followed with clinical symptoms and CT studies. Results: Most of all the 31 patients were improved. However, one patient was suffered from postoperative epidural hematoma and the other patients have received the secondary operation because of the recurrence of CSDH on 3 months after initial surgery. Conclusion: TDD is safe procedure for the symptomatic CSDH if the patients are selected appropriately.