• 제목/요약/키워드: Recovery of strength

검색결과 518건 처리시간 0.028초

위편조직(緯編組織)의 물성(物性)에 관한 연구(硏究) (A Study of the Physical Properties of Weft Knit Fabrics)

  • 김인숙;이순홍
    • 패션비즈니스
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    • 제2권4호
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    • pp.93-101
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    • 1998
  • Knit products which had been limited only to underwear, recently became popularized, fashionized and highly classified covering even outer garments such as sportswear like golfwear, woman's dress, and man' s suit. As fashion cycle is getting shorter and the more a nation advanced prefers knit to woven fabrics knit industry has a very bright prospect, particularly woman's knit which is sensitive to fashion can be said as a fashion product with high value added. This study is to grasp the physical properties of stitch which are fundamental to the development of knit products. For this purpose, 2/20s of 100% wool were woven by the author of this study to basic plain stitch, rib stitch, varied transfer stitch, and float stitch on a SEMASEIKI cross knitter 7G to test the physical properties, and the result was as follows; 1. As for the relation between knit stitch and rate of extension recovery, rate of extension recovery was higher in the course direction than in the wale direction of three stitches except transfer stitch; rib stitch showed the highest rate of extension recovery in the course direction while float stitch showed the highest rate of extension recovery in the wale direction. 2. As for the relation between knit stitch and bursting strength elastic rib stitch showed higher bursting strength to indicate elasticity is an important factor of bursting strength and float stitch showed higher bursting strength too to indicate that the floating yarn on the surface plays a role of support. 3. As for the relation between knit stitch and air permeability perforated transfer stitch showed the lowest air permeability to prove that the size of perforation affects on the air permeability a great deal. 4. As for the relation between knit stitch and warmth retaining rib stitch through two lined needle bar showed the highest degree. The reason the warmth of perforated transfer stitch didn't decrease much was because the perforation wasn't big enough and content of air increased from the unevenness of the perforated parts through stitch variation. Based upon this result, each stitch can be characteristically summarized as follows; plain stitch showed a stable condition of knit cloth in four kinds of physical property test. And rib stitch is proper to tighten the edge of sleeve or clothe making use of its excellent extension recovery and to make socks for the highest bursting strength and warmth retaining. In the case of transfer stitch, seasonable designs can be taken by controlling the size of loop. Considering the pleasantness, underwear should be made of stitches with good air permeability float stitch was revealed to have color and pattern effects and a great bursting strength. This study has limitations in the aspect that it dealed with a small part of various knit stitches and the items of physical property test were not enough. The author of this study hopes that further studies would make deeper understandings about knit stitch based on more varied stitches and physical property tests ultimately to contribute to the development of fashionable designs proper to maximize the usage, function and originality.

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크롬유혁의 인공땀액 처리에 의한 물성변화 (Changes on Physical Properties of Chrome Leather by Treatment with Artificial Perspiration)

  • Yoon, Jeong Ah;Choi, Suk Chul;Lee, Yang Hun;Chun, Tae Il
    • 한국염색가공학회지
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    • 제7권4호
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    • pp.25-32
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    • 1995
  • This study was carried out to examine the influences of fatigue and perspiration on the deterioration of chrome leather for shoes. The samples were treated with acidic and alkaline artificial perspirations and applied cyclic tensile stress, and the elastic recovery from fatigue strain, tensile strength and elongation, stiffness etc. by regions and directions were determined. The physical properties generally indicate considerable difference by regions and directions due to the thickness, entangling state, and arrangement direction of fiber buldles within the leather. By the treatment of artificial perspirations, the length, weight, strength, elastic recovery from fatigue of the lether are decreased and the thicknes, elongation, and stiffness are increased; and their extents by the alkaline perspiration are higher than those by the acidic one. The elastic recovery from fatigue of samples are decreased with increasing fatigue cylcle; and indicate regressive relations against the logarithm of the elapsed time, and the means of regression coefficients are 2.73 > 2.55 > 2.22 for samples treated by the acidic perspiration, untreated, and treated by the alkaline perspiration, respectively. The tensile strength is decreased and elogation is increased by fatigue, but the changes are diminished likely due to a rearrangment of fiber bundles with increasing fatigue cycle. And the samples become a little flexible immediately after fatigue; but stiffen again with elastic recovery from fatigue strain, consequently for some cases their stiffness after recovery are rather greater than those before fatigre.

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다층용접한 저합금 용접금속의 강도와 인성에 미치는 입열량 및 예열/패스간 온도의 영향 (Effects of Heat Input and Preheat/interpass Temperature on Strength and Impact Toughness of Multipass Welded Low Alloy Steel Weld Metal)

  • 방국수;정호신;박찬
    • 한국해양공학회지
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    • 제29권6호
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    • pp.481-487
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    • 2015
  • The effects of the heat input and preheat/interpass temperatures on the tensile strength and impact toughness of multipass welded weld metal were investigated and interpreted in terms of the recovery of the alloying elements and microstructure. Increases in both the heat input and preheat/interpass temperatures decreased the tensile strength of the weld metal. A lower recovery of alloying elements, especially Mn and Si, and smaller area fraction of acicular ferrite in the weld metal were observed in higher heat input welding, resulting in a lower tensile strength. In contrast, only a microstructure difference was observed at a higher preheat/interpass temperature. The impact toughness of the weld metal gradually increased with an increase in the heat input because of the lower tensile strength. However, it decreased again when the heat input was larger than 45 kJ/cm because of the much smaller area fraction of acicular ferrite. No effect of the preheat/interpass temperature on the impact toughness was observed. The formation of a weld metal heat-affect zone showed little effect on the impact toughness of the weld metal in this experiment.

Effects of Different Cool-down Exercise Methods on Muscle Strength and Endurance of the Lower Extremities

  • Bae, Chang-Hwan;Cho, Sung-Hyoun;HwangBo, Gak
    • International Journal of Contents
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    • 제8권2호
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    • pp.97-102
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    • 2012
  • The purpose of this study was to investigate the effects of various cool-down exercises on muscular strength and endurance. After receiving a treadmill training for main exercise, the subjects conducted isotonic and isometric cool-down exercises four times for three weeks. Isotonic exercise with leg press of 10kg was repeated by 20 times and isometric exercise was conducted at flexion of hip joint and knee joint with leg press of 10kg by maintaining it for 6 sec and resting for 2 sec by 20 times. Muscular strength after exercise was measured with 1 RM by times and muscular endurance with maximum repetition frequency using time to keep for loading the weight of 10 RM and 65% of maximum muscular strength. As a result of comparing and analyzing measured values, exercise recovery shape of isotonic and isometric cool-down group were more effective than rest recovery shape of the control group. The isometric cool-down group was more effective than isotonic cool-down group. In conclusion, isometric exercise was more effective than isotonic exercise or simple rest on muscular strength and endurance.

음악요법이 수술직후 환자의 의식회복과 활력징후에 미치는 영향 (The Effects of Music Therapy on recovery of consciousness and vital signs in post operative patient in the recovery room)

  • 김숙정;전은희
    • 기본간호학회지
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    • 제7권2호
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    • pp.222-238
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    • 2000
  • The purpose of this study was to demonstrate the effect of music therapy as a nursing intervention on changes in recovery of consciousness and vital signs for postoperative patients in the recovery room. The subject for this study were fifty three of postoperative patients who were transferred from the OR to the RR at Kwangju Christian Hospital in Kwangju City. Thirty of them were assigned to the experimental group, and twenty three, to the control group. The age of the subject was between twenty and sixty years of age. The subject had a general anesthesia without any special complications, and they were not completely awake. The data were collected for six months from July 1999 to February 2000. The method used was to compare the condition of the subjects in each group at the beginning and at certain times repeatedly. The features observed were the level of consciousness, the frequency of complaints of pain, and vital signs of the subject before and 15 minutes, 30 minutes, and 60 minutes after hearing their favorite music for 30 minutes. The results are as follows 1. The recovery of consciousness was revealed through significant changes in facial expression, facial color, and grip strength in the experimental group more strongly than in the control group. No significant changes were shown in verbal order. The differences in recovery of consciousness in the pre-post music therapy between the two groups was not significant in verbal order, facial expression, or grip strength. However, significant changes were seen in facial color. 2. There were no significant differences between the two groups in changes in the frequency of pain complaints after music therapy. However, a significant difference was shown in the pre-post music therapy scres. 3. Vital signs did not show a significant difference between the two groups. However, the $SPO_2$ of the experimental group was significantly elevated after 60 minutes. The difference pre-post to the music therapy in the vital signs between two groups was significant only in body temperature. This study showed that the effect of music therapy given to postoperative patients is that it promotes changes in facial expression, facial color, and grip strength helping recovery of consciousness, stabilizing vital signs, elevating levels of $SPO_2$. and reducing complaints of pain. It is recommended that if the patient wants it music therapy be given right after surgery in the recovery room as a nursing intervention.

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A computational analysis of the scarf angle on a composites repair

  • Kim, Yun-Hae;Jo, Young-Dae;Murakami, Ri-Ichi
    • International Journal of Ocean System Engineering
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    • 제1권1호
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    • pp.9-15
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    • 2011
  • This study examined the relationship between the scarf angle and stress distribution, and estimated the strength recovery via a finite element analysis. The following conclusions were drawn from this study. Resin will fracture due to a tensile load with a high scarf angle, which is similar to the patch repair method. An applied stress can be loaded to a repaired laminate if the scarf angle is $5^{\circ}$. The Von-Mises stress increases with decreasing scarf angle, with the exception of a scarf angle of $30^{\circ}$, where the scarf angle can indicate the rates of shear and normal stresses. Strength recovery can be better if the scarf angle is decreased to a lower angle. However, scarf machining requires more time, a high skill level and considerable expense. Therefore, a scarf angle of $5^{\circ}$ is the most effective for a repair. These results may provide a guide for engineers wishing to formulate a standard for repair. The scarf angle needs to be carefully managed for a more efficient composite repair.

800kV 모델차단부의 극간 절연회복특성 -I. 가동주접점과 가동아크접점간 이격거리의 변화에 대한 영향분석- (Dielectric Recovery Characteristics between Poles of 800kV Model Interrupter -I. Effects or separation between Moving Main Contact and Moving Arcing Contact-)

  • 신영준;박경엽;장기찬;송기동;정진교;송원표;강종호
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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    • pp.270-273
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    • 1994
  • The capacitive current breaking capability as well as the short circuit current breaking capability is a very important factor in the performance of a circuit breaker. The dielectric recovery capability between poles should be considered in the desist of a circuit breaker because approximately two times of the maximum power system voltage might be applied between poles after the capacitive current be interrupted. The electric field and flow field analyses were utilized in the calculation of dielectric recovery characteristics between poles of 800kV model interrupter. The results show that the separation between moving main contact and moving arcing contact will affect to decrease significantly the electric field strength of a moving arcing contact and an insulation cover, to increase slightly the electric field strength of a fixed arcing contact and to decrease consequently the dielectric recovery capability between poles of the interrupter.

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레이온 직물의 Wet-Fixation에 의한 DP가공에 관한 연구(I) - 일욕법과 이욕법의 비교 - (A Study on the Durable Press Finish by Wet-Fixation Processes for Rayon Fabrics (I) - One Bath and Two Bath Processes -)

  • 허윤숙;김은애
    • 한국의류학회지
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    • 제13권3호
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    • pp.242-251
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    • 1989
  • The purpose of this study was to investigate the changes in easy-care and strength properties of the wet fixation processed viscose rayon fabrics. Rayon fabrics were treated with mixed resins of melamine formaldehyde (MF) and DMDHEU by one bath and two bath wet fixation processes. The MF/DMDHEU mixed resin concentrations were 50/100, 50/150, 100/100, 100/150 and 150/100(g/1). Magnasium chloride was used as a catalyst. Treated fabrics were evaluated by nitrogen content, DP rating, wrinkle recovery angle, breaking strength, tearing strength and abrasion resistance. The properties were compared to the fabrics treated by conventional Pad-Dry-Cure (PDC) method. Wet fixation processed fabrics showed DP ratings of higher than 3 and higher than 275 degrees of wrinkle recovery angles in all the mixed resin concentrations. Wet fixation processed fabrics showed increase in breaking strength and tearing strength but decrease in abrasion resistance. However, the decrease in abrasion resistance was much less than the conventional PDC treated fabrics. The one bath wet fixation processed fabrics showed better physical properties than the two bath processed fabrics in general. The optimum treatment condition was the mixed resin concentration of MF/DMDHEU, 100/100 g/l in one bath wet fixation process.

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DMIDR 장치의 재구성 알고리즘 별 성능 평가 (Performance Evaluation of Reconstruction Algorithms for DMIDR)

  • 곽인석;이혁;문승철
    • 핵의학기술
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    • 제23권2호
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    • pp.29-37
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    • 2019
  • DMIDR (General Electric Healthcare, USA)은 GE 사(社)의 최신 장비로써 PSF (Point Spread Function reconstruction), TOF(Time of Flight)와 Q.Clear의 적용이 가능하다. 특히, Q.Clear는 보정 알고리즘으로써 복셀(voxel)단위 신호 잡음 제거로 기존 OSEM (Ordered Subset Expectation Maximization)의 한계를 넘어설 수 있다. 따라서 이러한 재구성 및 보정 알고리즘의 성능 평가를 통해 정확한 SUV를 구현하며, 병변 검출 능력에 도움이 되는 알고리즘의 조합을 확인하고자 하였다. H/B(Hot & Background) Ratio 2:1, 4:1, 8:1의 비율로 NEMA/IEC 2008 PET phantom을 제작하였다. DMIDR의 NEMA test protocol을 이용하여 영상 획득을 하였다. 재구성 조합은 (1) VPFX(VUE point FX(TOF)), (2) VPHD-S(VUE point HD+PSF), (3) VPFX-S(TOF+PSF), (4) QCHD-S-400(VUE point HD+Q.Clear(${\beta}-strength$ 400)+PSF), (5) QCFX-S-400(TOF+Q.Clear(${\beta}-strength$ 400)+PSF), (6) QCHD-S-50(VUE point HD+Q.Clear(${\beta}-strength$ 50)+PSF), (7) QCFX-S-50(TOF+Q.Clear(${\beta}-strength$ 50) + PSF)의 7 가지로 구성하였다. H/B Ratio 및 재구성 알고리즘 별로 측정된 결과를 이용하여 CR (Contrast Recovery)와 BV (Background Variability)을 구하였다. 또한, 각 조합의 count를 측정하여 SNR (Signal to Noise Ratio)과 RC(Recovery Coefficient)를 구하고 SUV (Standardized Uptake Value)를 측정하였다. 구의 크기가 가장 작은 10 mm와 13 mm에서는 VPFX-S, 17 mm 이상에서는 QCFX-S-50에서 가장 높은 CR 결과를 보였다. BV와 SNR의 비교에서는 QCFX-S-400과 QCHD-S-400에서 좋은 값을 보였다. SUV 측정 결과는 H/B ratio와 비례하여 증감하는 양상을 보였다. SUV에 대한 RC의 경우 H/B ratio와 반비례하는 양상을 보였으며, 재구성 알고리즘 중에서는 QCFX-S-50이 가장 높은 값을 보였다. 또한, Q.Clear에 ${\beta}-strength$ 400이 적용된 재구성 알고리즘들이 낮은 값 분포를 보였다. Q.Clear가 적용된 재구성 조합은 ${\beta}-strength$를 높이면 신호잡음이 억제되어 영상 품질면에서 우수한 결과를 보였고 ${\beta}-strength$를 낮추면 선예도가 증가하며, partial volume effect가 감소하여 기존의 재구성 조건에 비하여 높은 RC에 근거한 SUV 측정이 가능하였다. 이러한 진보된 알고리즘의 사용으로 보다 정확한 정량화와 미세병변 검출능력을 향상 시킬 수 있으나 상관 관계를 고려하여 목적에 맞는 최적화 과정이 필요할 것으로 사료된다.

동절기 초기재령에서 동해를 받은 고강도콘크리트의 내동해성 평가에 관한 실험적 연구 (Experimental Study on the Evaluation of frost-Resistance of High-Strength Concrete Damaged by frost at Early Age in Cold Climates)

  • 권영진
    • 콘크리트학회논문집
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    • 제13권2호
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    • pp.139-145
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    • 2001
  • 보통강도의 한중콘크리트에 있어서 동해는 일반적으로 콘크리트의 공기량 및 양생방법 등에 의해 억제시킬 수 있는 것으로 알려져 있으며, 고강도콘크리트는 낮은 물결합재비로 인하여 동결융해저항성이 우수한 것으로 알려져 있지만, 한중콘크리트 타설 및 초기양생에 있어서 발생될 수 있는 초기동해에 관한 연구는 아직 미흡한 실정이다. 따라서 본 연구에서는 동절기에 고강도콘크리트를 타설할 경우 초기동해에 의해 발생되는 인장응력의 영향을 고려하여 인장강도비를 검토하고, 초기동해를 입은 경우 장기재령에 의한 강도회복성을 검토하여 동절기 고강도콘크리트의 현장적용을 위한 기초적 자료로서 제시하고자 한다. 본 연구의 결과 초기동해를 입은 고강도콘크리트의 내동해성은 동해를 받은 시점이 빠를수록 공기량이 적을수록 저하하는 것으로 나타났으며, 내동해성을 확보하기 위해서는 공기량 4% 이상을 확보해야 할 것으로 사료되며, 동해를 받은 후 양생에 의한 압축강도의 회복성능은 W/C가 낮을수록 초기동해를 받기 전 양생기간이 증가할수록 향상되는 것으로 나타났다. 또한 향 후 고강도콘크리트의 동절기 시공에 있어서 초기동해에 대한 내동해성을 지니기 위해서는 인장강도 5kgf/$\textrm{cm}^2$ 이상을 확보해 야 할 것으로 사료된다.