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Manufacturing and Mechanical Properties of Epoxy Fibers Spinning using Anhydride and Amine Hardeners (산 무수물계 및 아민계 경화제를 이용한 열경화성 에폭시 섬유 제조 및 물성)

  • Shin, Pyeong-Su;Kim, Jong-Hyun;Park, Ha-Seung;Baek, Yeong-Min;Kwon, Dong-Jun;Park, Joung-Man
    • Composites Research
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    • v.29 no.6
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    • pp.408-413
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    • 2016
  • Commonly-used polymers are manufactured as versatile forms. Furthermore, continuous polymer fibers are recently manufactured using nylon or aramid fiber. One of common epoxy was also used to make polymer fibers. Bisphenol-A type was used as base epoxy whereas amine and anhydride were used as hardeners. Epoxy fibers was cured by stepping up the temperature to maintain the shape of epoxy fiber. Surface energy was measured to confirm the degree of interfacial adhesion by modified static contact angle method. After mechanical properties were measured via fiber tensile test, the evaluation of fiber fracture was proceeded. Tensile strength of epoxy fiber using amine type hardener was higher as 138 MPa than anhydride case as 70 MPa. Fractured surface exhibited different failure patterns at the cross-section.

Analysis Method for Damage Patterns of Low Voltage Switches for PL Judgment (PL 판정을 위한 저압용 스위치의 소손 패턴 해석기법)

  • Choi, Chung-Seog
    • Fire Science and Engineering
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    • v.24 no.5
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    • pp.136-141
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    • 2010
  • The purpose of this study is to examine the structure and heat generation mechanism of low voltage switches used to turn on or off the power supply to an indoor lighting system and investigate how the fixtures and movable contacts of the switches are damaged depending on the types of energy sources in order to secure the judgment base for expected PL disputes. Based on the Korean Standard (KS) testing method for incombustibility, this study applied a general flame to the switch. In addition, current was supplied to the switch using the PCITS (Primary Current Injection Test System). The ambient temperature and humidity were maintained at $22{\pm}2^{\circ}C$ and 40~60% respectively while performing the test. It is thought that the switch generated heat due to a defective connection of the wire and clip, insulation deterioration and defective contact of the movable contact, etc. The surface of the switch damaged by the general flame was uniformly carbonized. When the flame source was removed, the fire on the switch was extinguished naturally. From the result obtained by disassembling the switch carbonized by the general flame, it could be seen that fixtures and movable contacts remained in comparatively good shape but the enclosure, clip support, movable contact, indicating lamp, etc. showed carbonization and discoloration. In the case of the switch damaged by overcurrent, the clip connecting the wires, clip support, etc. showed almost no trace of damage, but the fixtures, movable contact, indicating lamp, etc. were severely carbonized. That is, the sections with high contact resistance were intensively damaged and showed a damage pattern indicating that carbonization progressed from the inside to the outside. Therefore, it is possible to judge the initial energy source by analyzing the characteristics of the carbonization pattern and the metal fixtures of damaged switches.

Manufacture of Fermented Cantaloupe Melon with Lactic Starter Culture (유산균을 이용한 참외 발효식품의 제조)

  • Cha, Seong-Kwan;Chun, Hyong-Il;Hong, Seok-San;Kim, Wang-June;Koo, Young-Jo
    • Korean Journal of Food Science and Technology
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    • v.25 no.4
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    • pp.386-390
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    • 1993
  • Addition of starch syrup, table sugar, potato powder, skim milk powder an parched soybean powder to melon flesh was suitable as fermented melon base. The manufacturing process of fermented melon was as follows: Pasteurization for 10 min at $95^{\circ}C$, use of 1% starter culture, fermentation for 12 hours at $35^{\circ}C$ and ripening for 3 days at $8^{\circ}C$. The growth and acid production of Pediococcus acidilactici among several starter cultures were most active for the first 12 hours, but such activities were disappeared during ripening. In the case of Lactobacillus plantarum, the activities were not high during fermentation, which, however, increased during ripening. Throughout the whole manufacturing process, the fermented melon with a mixed culture of P. acidilactici and L. plantarum showed more cell number of each bacterium and higher titratable acidity than that with single cultures. Also P. acidilactici surpressed the growth of L. plantarum during ripening.

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Dose-Dependent Associations between Wine Drinking and Breast Cancer Risk - Meta-Analysis Findings

  • Chen, Jia-Yan;Zhu, Hong-Cheng;Guo, Qing;Shu, Zheng;Bao, Xu-Hui;Sun, Feng;Qin, Qin;Yang, Xi;Zhang, Chi;Cheng, Hong-Yan;Sun, Xin-Chen
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.3
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    • pp.1221-1233
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    • 2016
  • Purpose: To investigate any potential association between wine and breast cancer risk. Materials and Methods: We quantitatively assessed associations by conducting a meta-analysis based on evidence from observational studies. In May 2014, we performed electronic searches in PubMed, EmBase and the Cochrane Library to identify studies examining the effect of wine drinking on breast cancer incidence. The relative risk (RR) or odds ratio (OR) were used to measure any such association. Results: The analysis was further stratified by confounding factors that could influence the results. A total of twenty-six studies (eight case-control and eighteen cohort studies) involving 21,149 cases were included in our meta-analysis. Our study demonstrated that wine drinking was associated with breast cancer risk. A 36% increase in breast cancer risk was observed across overall studies based on the highest versus lowest model, with a combined RR of 1.0059 (95%CI 0.97-1.05) in dose-response analysis. However, 5 g/d ethanol from wine seemed to have protective value from our non-linear model. Conclusions: Our findings indicate that wine drinking is associated with breast cancer risk in a dose-dependent manner. High consumption of wine contributes to breast cancer risk with protection exerted by low doses. Further investigations are needed for clarification.

Association between Circulating Vitamin D, the Taq1 Vitamin D Receptor Gene Polymorphism and Colorectal Cancer Risk among Jordanians

  • Atoum, Manar Fayiz;Tchoporyan, Melya Nizar
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.17
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    • pp.7337-7341
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    • 2014
  • Background: The physiological role of vitamin D extends beyond bone health and calcium-phosphate homeostasis to effects on cancer risk, mainly for colorectal cancer. Vitamin D may have an anticancer effect in colorectal cancer mediated by binding of the active form $1,25(OH)_2D$ to the vitamin D receptor (VDR). The Taq1 VDR gene polymorphism, a C-to-T base substitution (rs731236) in exon 9 may influence its expression and function. The aim of this study wass to determine the 25(OH)D vitamin D level and to investigate the association between circulating vitamin D level and Taq1VDR gene polymorphism among Jordanian colorectal cancer patients. Materials and Methods: This case control study enrolled ninety-three patients and one hundred and two healthy Jordanian volunteers from AL-Basheer Hospital/Amman (2012-2013). Ethical approval and signed consent forms were obtained from all participants before sample collection. 25(OH)D levels were determined by competitive immunoassay Elecsys (Roche Diagnostic, France). DNA was extracted (Promega, USA) and amplified by PCR followed by VDR Taq1 restriction enzyme digestion. The genotype distribution was evaluated by paired t-test and chi-square. Comparison between vitamin D levels among CRC and control were assessed by odds ratio with 95% confidence interval. Results: The vitamin D serum level was significantly lower among colorectal cancer patients (8.34 ng/ml) compared to the healthy control group (21.02ng/ml). Patients deficient in vitamin D (less than 10.0 ng/ml) had increased colorectal cancer risk 19.2 fold compared to control. Only 2.2% of CRC patients had optimal vitamin D compared to 23.5% among healthy control. TT, Tt and tt Taq1 genotype frequencies among CRC cases was 35.5%, 50.5% and 14% compared to 43.1%, 41.2% and 15.7% among healthy control; respectively. CRC patients had lower mean vitamin D level among TT ($8.91{\pm}4.31$) and Tt ($9.15{\pm}5.25$) genotypes compared to control ($21.3{\pm}8.31$) and ($19.3{\pm}7.68$); respectively. Conclusions: There is significant association between low 25(OH)D serum level and colorectal cancer risk. The VDRTaq1 polymorphism was associated with increased colorectal cancer risk among patient with VDRTaq1 TT and Tt genotypes. Understanding the functional mechanism of VDRTaq1 TT and Tt may provide a strategy for colorectal cancer prevention and treatment.

Long Term Outcomes of Laser Conization for High Grade Cervical Intraepithelial Neoplasia in Thai Women

  • Wongtiraporn, Weerasak;Laiwejpithaya, Somsak;Sangkarat, Suthi;Benjapibal, Mongkol;Rattanachaiyanont, Manee;Ruengkhachorn, Irene;Chaopotong, Pattama;Laiwejpithaya, Sujera
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.18
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    • pp.7757-7761
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    • 2014
  • Aim: To report long term outcomes of laser conization for high grade cervical intraepithelial neoplasia (CIN) in Thai women. Materials and Methods: A retrospective cohort study was conducted in patients undergoing laser conization due to abnormal cervical cytology suggesting neoplasia during 1989 to 1994 and having follow-up data until December 2010. Conization was performed under colposcopy using a 0.5-mm $CO_2$ laser beam with power density of $18,000-20,000watts/cm^2$, and the surgical base was vaporized using a low power defocused beam. The follow-up protocol included cervical cytology and colposcopy. Long term outcome measures were failure rate (persistence and recurrence), post-conization status of transformation zone, and obstetric outcomes. Results: Of 104 patients undergoing conization, 71 had therapeutic conization for high grade CIN and were followed up for a median time of 115 (range 12-260) months. There was one case of persistent and one of recurrent disease comprising a failure rate of 2.8%. The post treatment transformation zone was well visualized in 68.3% of 63 patients with an intact uterus. Sixteen patients achieved 25 pregnancies; none had second trimester miscarriage. The obstetric outcomes were unremarkable. Conclusions: Laser conization under colposcopic visualization for the treatment of high grade CIN in Thai women has a low failure rate of 2.8%. The post-conization transformation zone could not be evaluated completely in approximately 30% of cases; therefore the follow-up protocol should include both cytology and colposcopy. Obstetric outcomes are not adversely affected by this therapeutic procedure.

Improving the Detection of the Water Mains Underground Facilities (상수도 지하시설물 탐사 개선에 관한 연구)

  • Kim, Jae-Myeong;Lee, Byung-Woon;Choi, Yun-Soo;Yoon, Ha-Su
    • Spatial Information Research
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    • v.18 no.4
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    • pp.23-32
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    • 2010
  • Water mains underground facilities are essential components to make up urban infrastructure. In order to manage these water mains underground facilities systematically and scientifically, GIS (Geographic Information System) had been constructed. For the sake of construction of GIS for water mains underground facilities, an exact underground detection and the construction of DB (Data Base) for buried water mains underground facilities should be preceded. In this study, in order to find out the ways to improve exact detection rate of data, the statistical analysis for the causes of detection raw degradation was done, and standardization methods of detection through a case study were suggested, When water mains underground facilities were measured, the detection of non-metallic water pipes was not carried out. The reason was that the results of detection was uncertain and detection was difficult because the assessment of public measurements was vulnerable. Moreover, due to the absence of standardized operating regulations for detection, systematic surveys weren't conducted. In this study, methods to standardize works over the detection of water mains underground facilities were presented so that we can improve the detection rate when we are doing that. As the proposals to improve detection rate, effective performance assessment over non-metallic pipes were presented, and related issues to supplement work regulations of public survey were described systematically.

A Study on the Proposal of Spiral Evolution Model of IPTV, M-IPTV, OTT & Smart Media focusing on Exploration & Exploitation Theory (IPTV, M-IPTV, OTT, 스마트미디어 진화단계에 관한 탐색과 활용관점의 Spiral 모형 연구)

  • Lee, Sang-Ho;Kim, Jai-Beom;Kim, Young-Berm
    • Journal of Digital Contents Society
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    • v.15 no.3
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    • pp.327-338
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    • 2014
  • This study proposes the evolution model of emerging media platform including smart media (M-IPTV, Smart TV) and IPTV, through a spiral evolution model based on the theory of the exploration & the exploitation. Authors suppose that the IP media evolved from IPTV technology, evolution of which has come through the development model of serial circular process. For explanation of this evolution, we propose the research model integrating the spiral model and the exploration & exploitation theory. Researchers define the smart media as the evolved media from IPTV, through this proposed model. We expect this model to be the theoretical base of media regulation and setting direction of future media service. Thus, this research are summed up as follows. To begin with, we classify the evolutionary stage of IPTV from the view points of service feature, regulation frame and technological characters. Secondly, we organize and confirm the research model of IPTV evolution through case analysis of the 3 cycles of each evolutionary stage. As a result, discussion of this study helps understanding mobile IP media and smart media as a post IPTV and leads the solution of various regulation issues and the development of the innovative media service and content. In addition, it can guide the government for the evolutionary direction to promote the media and the content industry.

ICT-based Living in the Contact Type Service Model for Self-life Support of the Elderly Living Alone (독거노인 자가생활지원을 위한 ICT기반의 생활밀착형 서비스 모델 개발)

  • Kim, Mi-Yun;Seo, Dong-Jo;Byun, Jong-Bong;Kang, Jong-Kwan
    • Journal of Digital Convergence
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    • v.13 no.4
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    • pp.25-38
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    • 2015
  • In case of current South Korea, the rapid graying is in the progress. Because of it, the increase of elders who live alone causes variety of social, economic and national problems. Especially in the modern city, the health care, safety and maintenance of pleasant and joyful life of elders who live alone are being a big social issue. Even though practical services have been tried at the whole of government approach, the detailed alternatives are insufficient to improve the daily life support and service to approach the information. This research suggests the "ELA Service Model" which actively improves the easy access to information and corresponds to condition and circumstance of elders for providing the ICT-base Elderly Living alone care service. It is a step self-life support service based on fundamental desire of elders which resolves the problem and contributes to establish the active and balanced policy to the elderly.

The examination of application possibility and development of new welding joint shape for aluminum alloy (Al어선 선체용접부의 신형상 개발 및 적용 가능성 검토)

  • Jong-Myung Kim;Chong-In Oh;Han-Sur Bang
    • Journal of the Society of Naval Architects of Korea
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    • v.38 no.1
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    • pp.99-107
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    • 2001
  • Manufacture of fishing vessel is needed the effective material for light, strength, fire and corrosion of water in order to improve durability by high-speed and fishing. These fishing vessel can be divided into FRP and AI alloys fishing vessel. FRP fishing vessel is light and effective for strength but highly ignited and susceptible to heat during the manufacturing ship by-produce noxious component for human. In the case of a scrapped ship, it cause environmental pollution. On the other hand, aluminum is a material in return for FRP and has merit of high-strength and lightness. It's more heat proof and durable than FRP and superior to prevent from corrosion. Al alloys fishing vessel development is rising as an urgent matter. But, al alloy has some defect of bad weldability, welding transformation, cracks and overcost of construction. Therefore this study is to develop the new welding joint shape solving aluminum defects and mechanical behavior. First of all, strength was compared and reviewed by analysis of plate, stiffen plate, new model simplified by using plate theory. On the base of this result, plate and new model of temperature distribution, weld residual stress and strength of tensile, compressive force were compared and reviewed by finite element computer program has been developed to deal with heat conduction and thermal elasto plastic problem. Also, new model is proved application possibility and excellent mechanic by strength comparison is established to tensile testing result.

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