• Title/Summary/Keyword: SF (stress fiber)

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A Study on the Mechanical Properties of Hybrid HPFRCs Using Micro and Macro Fibers (마이크로 및 매크로 섬유를 사용한 하이브리드 HPFRCC의 역학적 특성에 관한 연구)

  • Kim Jae Hwan;Lee Eui Bae;Kim Yong Sun;Kim Yong Duk;Joo Ji Hyun;Kim Moo Han
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.05a
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    • pp.276-279
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    • 2004
  • Concrete is one of the principal materials for the structure and it is widely used all over the world. but it shows extremely brittle failure under bending and tensile load. Recently to improve such a poor property. High Performance Fiber Reinforced Cementitious Composites (HPFRCC) have been developed. and it are defined by an ultimate strength higher than their first cracking strength and the formation of multiple cracking during the inelastic deformation process. This study is to develop the hybrid HPFRCC with high ductility and strain capacity in bending and tensile load. and the three-point bending test on hybrid HPRFCC reinforced with micro and macro fibers is carried out in this paper. As the results of the bending tests. hybrid HPFRCCs reinforced with PVA40+SF and PVA100+PVA660 showed the high ultimate bending stress, multiple cracks and displacement hardening under bending load.

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The Prevalence and Factors of Irritable Bowel Syndrome in University Students (일대학교 대학생의 과민성 장 증후군 유병률 및 영향요인 연구)

  • Lee, Kyung-Sook
    • Journal of Korean Biological Nursing Science
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    • v.11 no.2
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    • pp.167-175
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    • 2009
  • Purpose: The purpose of this study was to examine the prevalence and factors on Irritable Bowel Syndrome (IBS) symptoms in university students. Methods: This study was descriptive survey research. The subjects were 187 university students from one university. The exclusion criteria were 1) had GI surgery 2) had severe physiologic or psychologic problems 3) had liver, bile duct, pancreatic, and intestinal disease that required treatment. The ROME III was used to diagnose IBS. Sociodemographic characteristics, general health state by SF-36, psychological health by SCL-90-R, stress by perceived stress scale, sleep disturbance by Korean sleep scale, and diet habits were measured. Data were analyzed by using SPSS 17.0. Results: Seventeen students (9.1%) had IBS by ROME III criteria, but 46% had some GI problems at that time. Abdominal pain or discomfort continued for last six months or more in 14.3%. Fiber intake, obsessive-compulsiveness, hostility, psychoticism, global severity index, positive symptom distress, role physical, bodily pain, social functioning, and mental health were significantly different between IBS group and Non IBS group. Conclusion: Over nine percent of the students were diagnosed by Rome III criteria, and almost half of them had some GI problems. Diet, personality, general health state, and psychological health were factors of IBS.

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