• International Journal of Industrial Entomology and Biomaterials
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• 제16권2호
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• pp.61-66
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• 2008

In this paper, the regenerated silk fibroin (SF)/nylon 6 blend filaments were fabricated using wet spinning technique and the effect of coagulant on the post drawing and morphology of blend filaments was investigated. In the result of wet spinnability, methanol, acetone, DMF, and THF showed relatively good coagulation strength and fiber formation for the regenerated SF. On the contrary, they did not exhibit strong enough to produce a uniform nylon 6 filament due to the lack of coagulation strength. In the examination of post drawing performance, methanol showed the highest maximum draw ratio of the blend filament over all blend ratios. The maximum draw ratio of SF/nylon 6 blend filaments decreased with the reduction of SF content regardless of type of coagulant. SEM observation showed the consistent result with that of post-drawing performance. As SF content decreased, the uniform and regular structure was changed to irregular one. In particular, the severe macro-phase separation between SF and nylon 6 could be detected in the 50/50 SF/nylon 6 blend filaments coagulated in methanol and THF.

• 한국염색가공학회지
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• 제28권1호
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• pp.33-39
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• 2016

The crystal structure of nylon 56 fibers post extended by drawing process was investigated by synchrotron x-ray scattering measurement. In as-cast fiber, distinct (004) and (020) diffraction peaks were observed and they were related to initial metastable alignment of nylon molecules. With increase in the drawing ratio, (110) peak intensity was increased in vertical direction with decreasing (020) peak. At the same time, (004)' peak evolved position tilted to 29 degrees from the (004) peak. This evolution is directly related to stable crystalline phase of nylon 56 originated from additional formation of hydrogen bondings between N-H and C=O by post drawing process. We also compared density variation, stress-strain curves of the fiber as a function of drawing ratio and strain. The variations of density and tanacity also supported the increase of stable structure of nylon 56.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 춘계학술대회논문집
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• pp.70-76
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• 1999

Recently most of researches for deep drawing process using sheet metal have been performed on the formability of axisymmetric shape but there have not been any concrete reports on the formability of non-axisymmetric shape In addition the conventional shape radius of the punch and die has been determined by the trying-and-error using industrial experimence and post processing test and only approximate shape radius of the punch and die has been determined by the trying-and-error using industrial experience and post processing test and only approximate shape radius of the punch and die has been present So in this study the optimal shape radius of the punch and die in deep drawing process with biaxisymmetric blank shape would be proposed. Through the deep drawing experiment it is found that in order to obtain the optimal products especially shape radius of the punch and die in all processes is very important.

• 대한물리의학회지
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• 제8권4호
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• pp.513-523
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• 2013

PURPOSE: The purpose of this study was to investigate characteristics of the forced pulmonary function test effect and abdominal muscles activation by combined complex exercise with abdominal drawing-in maneuver training of chronic stroke patients. METHODS: 14 post stroke patients(10 males and 4 females) involved voluntary this study and we divided two groups into CEG(complex exercise group) and CEAG (complex exercise and abdominal drawing-in maneuver group).(n=7, per goup). Each groups implicated the 2 times, 30minute exercises for 6 weeks a day. The CEAG performed the complex exercise 15 minutes and 15 minutes of abdominal drawing-in maneuver. For data analysis, the mean and standard deviation were estimated; non-parametric independent t-test was carried out. RESULTS: According to the study, in the combined complex exercise with abdominal drawing-in maneuver group, FVC and activation of transversus abdominis/internal oblique were statistically significant difference compared to the complex exercise group. CONCLUSION: These results indicate that the combined complex with abdominal drawing-in maneuver was efficient in enhancing abdominal muscles activation and pulmonary function of chronic stroke patients.

• International Journal of Industrial Entomology and Biomaterials
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• 제19권1호
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• pp.181-185
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• 2009

In this paper, the regenerated silk fibroin (SF)/hydroxypropyl methylcellulose (HPMC) blend filaments were prepared by wet spinning and the effect of HPMC concentration on the post drawing and morphology of blend filaments was elucidated. The result of maximum draw ratio indicated that the wet spinnability of wet spun SF / HPMC was improved with increasing HPMC concentration until 8% and remained constant after that concentration. The SEM observation revealed that the enhanced wet spinnability of blend filaments was strongly related to the morphological change by increasing HPMC concentration. Regardless of HPMC concentration, as SF content was reduced, the wet spinnability of blend film decreased resulting in reduced maximum draw ratio. It was also found by SEM observation that the cross section of blend filament deviated from circularity with an increase of HPMC content.

• Fibers and Polymers
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• 제7권4호
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• pp.432-435
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• 2006

High Modulus and high tenacity polypropylene fibers have been prepared by drawing on a gradient heater. Results show that fiber properties are significantly affected by temperature profiles of final stage drawing on a gradient heater. The gradient drawn filaments showed superior mechanical properties when compared to filaments drawn over a constant temperature heater. Fibers with initial modulus of 16.4 GPa and tenacity of 670 MPa have been manufactured in the process. The nature of the gradient drawing had a significant effect on end properties. The superior mechanical properties are attributed to the high crystal perfection and crystallinity and low void fractions obtained at high draw ratios when drawn over a gradient heater.

• 소성∙가공
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• 제10권3호
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• pp.185-192
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• 2001

In order to obtain the optimal products in deep drawing process, elliptical deep drawing tests were carried out with several shape radii of the punch and die. As parameters on testing, shape radii of the punch and die were selected. In addition, the conventional shape radii have been determined by trial-and-error using industrial experience and post processing test, and only approximate shape radii of the punch and die have been presented. The optimal shape radii of the punch and die in elliptical deep drawing process with biaxisymmetric blank shape are proposed. In this study, we suggest the appropriate conditions to be applicable to the actual manufacturing processes through the experiment and finite element method.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2000년도 춘계학술대회논문집
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• pp.92-95
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• 2000

In order to obtain the optimal products in deep drawing process elliptical deep drawing tests were carried out with several shape radii of the punch and die. As parameters on testing shape radii of the punch and die were selected, In addition the conventional shape radii have been determined by trial=and-error using industrial experience and post processing test and only approximate shape radii of the punch and die have been presented. The optimal shape radii of the punch and die in elliptical deep drawing process with biaxisymmetric blank shape are proposed. In this study we suggest the appropriate conditions to be applicable to the catual manufacturing processes through the experiment and finite element method.

• 한국정밀공학회지
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• 제16권10호
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• pp.101-108
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• 1999

Most of researches for deep drawing process have been performed on the formability of axisymmetric blank, but there is an insufficient study on the formability of non-axisymmetric blank. In addition, the conventional blank shape has been determined by the trial-and-error method using industrial experience and post processing test. Therefore only approximated shape of the blank can be presented. In this study, the optimal blank shape and concrete drafting method in deep drawing process with biaxisymmetric elliptical shape is proposed. Through the deep drawing experiment, it is found that the optimal blank shape gives the most uniform thickness of the products in the first process

• 소성∙가공
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• 제9권2호
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• pp.120-127
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• 2000

Recently, most of researches for sheet metal deep drawing process have been performed on the formability of axisymmetric shape, but there are not any concrete reports on the formability of non-axisymmetric shape. In addition, the conventional shape radius of the punch and die has been determined by trial-and-error using industrial experience and post processing test, and only approximate shape radius of the punch and die has been presented. In this study, the optimal shape radius of the punch and die in deep drawing process with biaxisymmetric blank shape is proposed. Through the deep drawing experiment, especially it is found that in order to obtain the optimal products, and improvement of formability can be researched by selection of such punch and die shape radius that gives an adequate thickness distribution in all processes.