• Title/Summary/Keyword: special fibers

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Electronic Shielding Effectiveness of the Structure with Long-shape Aperture (Long-shape aperture를 갖는 구조물의 Electronic Shielding Effectiveness 연구)

  • Heo, Yu;Kim, Min-Ho;Kim, In-Seok;Baek, Young-Nam
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.810-813
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    • 2003
  • Wide spread using of mobile and handy electronic apparatus is giving rise to a question on the harmfulness of health and causing troubles when electical and electronic equipments are in use. This paper reports on the experimental results obtained by using a pliable and structured specimen that has a long shape aperture, made of stainless steel fibers. Based on the TEM mode transfer structure that was designed and manufactured through HFSS, we measured electromagnetic shielding effectives, where the network analyzer was applied. We could draw a conclusion from this research that the metal fabric showed a good electromagnetic shielding effect, mainly by means of the good reflex loss at the fiber surface. Even though the material itself possesses a good absorption loss. the specimen revealed that structural factors. e.g.. the shape of the aperture. the size of the aperture, etc., can have a more influence on the shielding effect than the components of material have. A special notice is required for modeling and analyzing the electromagnetic characteristics of metal fabrics, because there exists a strong possibility that multiple reflection can happen on the surface of metal fibers. which can presume a model of fiber bundle and fabric structure.

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Numerical Analysis of ECC Uniaxial Tension Behavior (ECC의 1축 인장 거동 해석)

  • Kim, Yun-Yong;Lee, Bang-Yeon;Kwon, Seung-Hee;Kim, Jeong-Su
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.04a
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    • pp.917-920
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    • 2008
  • ECC is a special kind of high performance cementititous composite which exhibits typically more than 2% tensile strain capacity by bridging microcracks at a crack section. Therefore, micromechanics should be adopted to obtain multiple cracking and strain hardening behavior. This paper propose a linear elastic analysis method to simulate the multiple cracking and strain hardening behavior of ECC. In an analysis, the stress-crack opening relation modified considering the orientation of fibers and the number of effective fibers is adopted. Furthermore, to account for uncertainty of materials and interface between materials, the randomness is assigned to the tensile strength(${\sigma}_{fci}$), elastic modulus($E_{ci}$), peak bridging stress(${\sigma}_{Bi}$) and crack opening at peak bridging stress(${\delta}_{Bi}$), initial stress at a crack section due to chemical bonding, (${\sigma}_{0i}$), and crack spacing(${\alpha}_cX_d$). Test results shows the number of cracking and stiffness of cracked section are important parameters and strain hardening behavior and maximum strain capacity can be simulated using the proposed method.

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A Case of Pressure Sore in Congenital Insensitivity to Pain with Anhidrosis (CIPA(Congenital Insensitivity to Pain with Anhidrosis)를 가진 환아에서 욕창의 치험례)

  • Hwang, Jae Ha;Park, Sun Hyung;Yoo, Sung In;Noh, Bok Kyun;Kim, Eui Sik;Kim, Kwang Seog;Lee, Sam Yong
    • Archives of Plastic Surgery
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    • v.33 no.5
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    • pp.669-671
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    • 2006
  • Purpose: Congenital insensitivity to pain with anhidrosis(CIPA) is a rare form of autosomal recessive peripheral sensory neuropathy. Patients with CIPA show loss of pain sensation, which leads to corneal ulcers and opacities, self-mutilation of the tongue and fingertips, as well as fractures with subsequent joint deformities and chronic osteomyelitis. The purpose of this report is to highlight the fact that pressure sores also are a potential complication of CIPA. Methods: This case report describes a patient presenting with pressure sores resulting from CIPA. A 5-year-old boy was referred to our department for the treatment of a $5{\times}5cm$ sacral pressure sore as a result of a hip spica cast applied for the treatment of a left hip joint dislocation. He had a history suggesting CIPA such as multiple bony fractures, mental retardation, recurrent hyperpyrexia, anhidrosis, and clubbing fingers due to oral mutilation. A microscopic examination of the sural nerve showed mainly large myelinated fibers, a few small myelinated fibers and an almost complete loss of unmyelinated fibers. After wound preparation for two weeks, the exposed bone was covered with two local advancement flaps. Results: Two weeks later, complete wound healing was achieved. A 16-month follow-up showed no recurrence. However, the patient presented with a new pressure sore on the left knee due to orthosis for the treatment of the left hip joint dislocation. Conclusion: The early diagnosis of CIPA and special care of pressure sores are important for preventing and treating pressure sores resulting from CIPA.

A study on the properties of commercial nonwoven fabrics (시판 부직포의 물성에 관한 연구)

  • Soon Song Wha
    • Journal of the Korean Society of Clothing and Textiles
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    • v.11 no.1
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    • pp.79-85
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    • 1987
  • The purpose of this study was to help the consumer about the care of nonwoven fabrics by investigation of the properties such as launderability. shrinkage, color fastness and strenth. Materials used were two types, soft and stiff, of commercial nonwoven fabrics. Deter-gents used were neutral detergents, synthetic detergents and dry cleaning solutions(perch-toro-ethylene) The results of this study were summerized as follows; 1. Laundering of nonwoven fabrics in low temperature is more ideal as morphological changes by laundering in high temperature were more prominent than that in low temperature. 2. Ironing of nonwoven fabrics wants more attention on environmental temperature as the rate of shrinkage in high temperature was higher than that in low temperature. Neutral detergents are more desirable as the rate of shrinkage of nonwoven fabrics by laundering with synthetic detergents was more prominent than that with neutral deter-gents. The rate of shringkage of nonwoven fabrics was not affected by dry cleanining. 3. Special care is wanted in order to prevent color transfer from non woven fabrics to polyester or wool during dry cleaning or laundering as the color fastness test show that color changes of nonwoven fabrics were not affected, but that color stain was increased on polyester or wool. 4. The strength was affected by composition of fibers and types of nonwoven fabrics, soft or stiff.

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Structural Performance of Stud Shear Connections using SHCC between Existing School Building Frame and Seismic Retrofitting Elements (기존 학교건물 골조와 내진보강요소 일체화를 위한 변형경화형 시멘트 복합체를 적용한 스터드 전단 접합부의 구조성능)

  • Kim, Sung-Ho;Yun, Hyun-Do
    • Journal of the Korean Institute of Educational Facilities
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    • v.20 no.4
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    • pp.35-43
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    • 2013
  • Some results of experimental investigation conducted to assess the effect of cement composite strength and ductility on the shear behavior and crack-damage mitigation of stud connections between existing reinforced concrete frame in school buildings and seismic strengthening elements from cyclically direct shear tests are described. The cement composite strengths include 50 for medium strength and 70 MPa for high strength. Two types of cement composites, strain-hardening cement composite (SHCC) and non-shrinkage mortar, are used for stud shear connection specimens. The special SHCCs are reinforced with hybrid 0.2% polyethylene (PE) and 1.3% polyvinyl alcohol (PVA) fibers at the volume fraction and exhibits tensile strain capacity ranging from 0.2 to 0.5%. Test result indicates that SHCC improves the seismic performance and crack-damage mitigation of stud shear connections compared with stud connections with non-shrinkage mortar. However, the performance enhancement in SHCC stud connections with transverse and longitudinal reinforcements is less notable for those without additional reinforcement.

Frey Syndrome after Retromandibular Approach for Condyle Fracture Reduction (하악과두골절 수술 후 발생한 Frey Syndrome)

  • Lee, Jae-Min;Ki, Eun-Jung;Cheon, Hae-Myung;Choi, Moon-Gi
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.35 no.6
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    • pp.376-380
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    • 2013
  • Frey syndrome is a disease characterized by abnormal sweating, facial redness, and rare pain by stimulation of taste sense on the limited area dominated by the auriculotemporal nerve and great auricular nerve. Although the developmental mechanism and histopathologic cause of Frey syndrome are still being debated, the most reliable theory is based on injury of the parathympathetic nerve connected to the auriculotemporal nerve continuing to abnormal regeneration. The other theory is that the sweat glands develop an increased sensitivity after degeneration of sympathetic fibers. Therapy of Frey syndrome includes drugs, radiographic treatment, and surgical treatment; however, in most cases, treatment is not satisfactory. This is a case report on a 24-year-old male patient with Frey syndrome caused by the fracture reduction with retromandibular approach after multiple facial traumas and spontaneous healing without any special treatment.

Balantidium honghuensis n. sp. (Ciliophora: Trichostomatidae) from the Rectum of Rana nigromaculata and R. limnocharis from Honghu Lake, China

  • Li, Ming;Li, Weidong;Zhang, Lei;Wang, Chong
    • Parasites, Hosts and Diseases
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    • v.51 no.4
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    • pp.427-432
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    • 2013
  • A new trichostome ciliate, Balantidium honghuensis n. sp., was isolated from the recta of Rana nigromaculata and R. limnocharis during parasite surveys in Honghu Lake, Hubei Province, central China in summmer of 2010 and 2011. Its detailed morphometric characters based on LM and SEM studies were described herein. The organism is oval in shape and thickly ciliated. The vestibulum is "V" shaped and occupies about 1/3 to 2/5 of the body length. The vestibular and nearby regions possess strong peripheral fibers which form a marked axial fiber about the cytopharynx. More than 10 contractile vacuoles are distributed along the periphery of the latter body. Comparisions were made between this new species and B. sinensis Nie, 1935. They were discriminated from each other in terms of general body forms, body size, and vestibulum shapes. Besides, special attention was paid to its high-speed daughter swarmers which we believed to be the infective stage of B. honghuensis. Possible infection routes of anura amphibian balantidia were discussed.

Neurobiological basis for learning disorders with a special emphasis on reading disorders (학습장애의 신경생물학적 기전 : 읽기장애를 중심으로)

  • Chung, Hee Jung
    • Clinical and Experimental Pediatrics
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    • v.49 no.4
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    • pp.341-353
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    • 2006
  • Learning disorders are diagnosed when the individual's achievement on standardized tests in reading, mathematics, or written expression is substantially below that expected for age, schooling, and level of intelligence. Subtypes of learning disorders may be classified into two groups, language-based type learning disorders including reading and writing disorder, and nonverbal type learning disorder (NLD) such as those relating to mathematics & visuospatial skills, and those in the autism spectrum. Converging evidence indicates that reading disorder represents a disorder within the language system and more specifically within a particular subcomponent of that system, phonological processing. Recent advances in neuroimaging technology, particularly the development of fMRI, provide evidences of a neurobiological basis for reading disorder, specifically a disruption of two left hemisphere posterior brain systems, one parieto-temporal, the other occipito-temporal. The former is the reading system for beginner reading, the latter for skilled reading. Compensatory engagement of anterior systems around the inferior frontal gyrus(Broca's area) and a posterior(right occipito-temporal) system is noted in persistent poor readers in long-term follow up study. The theoretical model proposed to explain NLD's source is not right hemisphere damage, but rather the white matter model. The working hypothesis of the white matter model is that the underdevelopment of, damage to, or dysfunction of cerebral white matter(long myelinated fibers) is the source of this disorder. The role of an evidence-based effective intervention in the remediation of children with learning disorder is discussed.

Spontaneous intaocular amelanotic melanomas in ktc:Sprague-Dawley rats (Ktc:Sprague-Dawley 랫드의 안구에 자연발생한 amelanotic melanoma)

  • Kang, Boo-hyon;Son, Hwa-young;Ha, Chang-su;Kim, Dae-yong
    • Korean Journal of Veterinary Research
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    • v.35 no.2
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    • pp.375-381
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    • 1995
  • Two intraocular tumors were identified in low and medium dosed groups of a carcinogenicity study using 200 males and 200 females Sprague-Dawley rats in Screening & Toxicology Research Center, Korea Research Institute of Chemical Technology. The tumors were grossly observed as white or yellow, unilateral nodules. They were approximately $1-2{\times}3-5mm$ in size. The tumors located in the region of iris and/or ciliary body invaded peripheral cornea. The microscopic features were usually composed of spindle cells arranged in parallel, forming gently curving bundles or whorls. The spindle cells had poorly defined cell boundaries, scant to moderate cytoplasm, fusiform nuclei and indistinct nucleoli. Mitotic figures were rare and areas of necrosis were present. The spindle cells had positive immunoreactivity for S-100 protein and vimentin but negative for desmin, collagen and HMB-45 antibody. In special histochemical studies, the spindle cells react with Gomori's stain for argyrophih fibers, Prussian blue stain for iron but negative with Masson-Fontana's stain for melanin granules. Ultrastructurally, cytoplasmic premelanosomes were not observed in the tumor cells due to the poor preservation of tumor masses. Based on the results, the tumors were diagnosed as amelanotic melanoma.

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Study on the Anchovy Boat seine- VI The Physical Properties of the Improved Head Rope and Ground rope (기선권현 강의 연구- VI 뜸줄 . 발줄 재료로서 개발된 로우프의 물리적 특성)

  • Lee, Byoung-gee;Sohn, Tae-jun;Roh, Gap-chul
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.16 no.1
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    • pp.23-26
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    • 1980
  • The pure polypropylen rope has been used for the head rope, and the lead cored polypropylen rope for the ground rope in the anchovy boat seine. These ropes revealed the disadvantage that deforms the net shape due to their elongation. Te improve the disadvantage, authors developed the rope of new construction which is cored by wires and wrapped by polypropylene fibers, 20mm in diameter for the head rope and 40tnm for the ground rope. To compare the physical properties of the improved rope with the conventional ones, some factors are valued and the following results are found. 1. The improved ropes rev~al some disadvantages, such as the head rope is heavier, the ground rope lighter, and both of them are stiffer than the conventional ones, contrary to the required condition of ropes) However no special difficulties are found in practical use. 2. The improved ropes display much advantages, such as elongation is 30 percent less, breaking strength is 35 precent greater, and elastic recovery is 10 percent greater than the conventional ones. Thus, it is considered that the improved ropes are more suitable for the head rope and the ground rope of the anchouy boat seine net than the conventional ones.

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