• Title/Summary/Keyword: Viton

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Effect of Tracer Composition on Spectrum and Intensity of Burning Flame (예광제 조성이 연소 불꽃의 스펙트럼 및 광도에 미치는 영향)

  • Kwon, Soon-Kil;Hwang, Jun-Sik;Lee, Sang-Mu
    • Journal of the Korea Institute of Military Science and Technology
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    • v.9 no.4
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    • pp.90-96
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    • 2006
  • Computer simulation was carried out to develop the tracer composition of a high performance to be able to be observed by not only the naked eye but also the thermal imaging system attached to the weapon system. The results of computer simulation show that the optimum Mg content among the trace compositions is about 40% and the formulation consisted of Viton A has a higher flame temperature compared with that of chloride compound. But the only use of Viton A radiates a yellow light and the composition adding a chloride compound radiates the red light. The light intensity of the tracer composition involving Viton A is higher than that of chloride compound. The tracer composition involving Viton A shows more clear images in case of all tests.

Survivability assessment of Viton in safety-related equipment under simulated severe accident environments

  • Ryu, Kyungha;Song, Inyoung;Lee, Taehyun;Lee, Sanghyuk;Kim, Youngjoong;Kim, Ji Hyun
    • Nuclear Engineering and Technology
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    • v.50 no.5
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    • pp.683-689
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    • 2018
  • To evaluate equipment survivability of the polymer Viton, used in sealing materials, the effects of its thermal degradation were investigated in severe accident (SA) environment in a nuclear power plant. Viton specimens were prepared and thermally degraded at different SA temperature profiles. Changes in mechanical properties at different temperature profiles in different SA states were investigated. The thermal lag analysis was performed at calculated convective heat transfer conditions to predict the exposure temperature of the polymer inside the safety-related equipment. The polymer that was thermally degraded at postaccident states exhibited the highest change in its mechanical properties, such as tensile strength and elongation.

Virtual Fitting System Using Deep Learning Methodology: HR-VITON Based on Weight Sharing, Mixed Precison & Gradient Accumulation (딥러닝 의류 가상 합성 모델 연구: 가중치 공유 & 학습 최적화 기반 HR-VITON 기법 활용)

  • Lee, Hyun Sang;Oh, Se Hwan;Ha, Sung Ho
    • The Journal of Information Systems
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    • v.31 no.4
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    • pp.145-160
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    • 2022
  • Purpose The purpose of this study is to develop a virtual try-on deep learning model that can efficiently learn front and back clothes images. It is expected that the application of virtual try-on clothing service in the fashion and textile industry field will be vitalization. Design/methodology/approach The data used in this study used 232,355 clothes and product images. The image data input to the model is divided into 5 categories: original clothing image and wearer image, clothing segmentation, wearer's body Densepose heatmap, wearer's clothing-agnosting. We advanced the HR-VITON model in the way of Mixed-Precison, Gradient Accumulation, and sharing model weights. Findings As a result of this study, we demonstrated that the weight-shared MP-GA HR-VITON model can efficiently learn front and back fashion images. As a result, this proposed model quantitatively improves the quality of the generated image compared to the existing technique, and natural fitting is possible in both front and back images. SSIM was 0.8385 and 0.9204 in CP-VTON and the proposed model, LPIPS 0.2133 and 0.0642, FID 74.5421 and 11.8463, and KID 0.064 and 0.006. Using the deep learning model of this study, it is possible to naturally fit one color clothes, but when there are complex pictures and logos as shown in <Figure 6>, an unnatural pattern occurred in the generated image. If it is advanced based on the transformer, this problem may also be improved.

An Improved VTON (Virtual-Try-On) Algorithm using a Pair of Cloth and Human Image (이미지를 사용한 가상의상착용을 위한 개선된 알고리즘)

  • Minar, Matiur Rahman;Tuan, Thai Thanh;Ahn, Heejune
    • Journal of Korea Society of Industrial Information Systems
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    • v.25 no.2
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    • pp.11-18
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    • 2020
  • Recently, a series of studies on virtual try-on (VTON) using images have been published. A comparison study analyzed representative methods, SCMM-based non-deep learning method, deep learning based VITON and CP-VITON, using costumes and user images according to the posture and body type of the person, the degree of occlusion of the clothes, and the characteristics of the clothes. In this paper, we tackle the problems observed in the best performing CP-VTON. The issues tackled are the problem of segmentation of the subject, pixel generation of un-intended area, missing warped cloth mask and the cost function used in the learning, and limited the algorithm to improve it. The results show some improvement in SSIM, and significantly in subjective evaluation.

The Investigation for the Cases and Cause of the Failures of the EPDM Sealed SOVs Used in the High Temperature Circumference (고온주변에서 사용되는 에틸렌-프로필렌-디엔 합성고무 봉인물질을 가진 솔레노이드구동밸브의 작동실패 사례 및 원인 분석)

  • Lee J.;Seo J. K.;Park C. T.;Kim Y. I.;Yoon J.
    • Proceedings of the KAIS Fall Conference
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    • 2004.06a
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    • pp.82-85
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    • 2004
  • EPDM 봉인물질을 가진 SOV의 작동실패 사례 및 원인을 분석해보면 많은 SOV 고장(SOV failures)은 결국 EPDM 봉인물질이 원인인 것으로 나타났다. SOV 고장은 SOV가 그것의 설계 범위를 초과하는 주위 온도(ambient temperature)에 노출되어 있었기 때문에 발생되었다. 그러한 SOV 고장은 증기누설, 주위 온도의 부정확한 평가 등의 원인에 의해 발생되었다. 또한 SOV 고장은 연속적인 coil의 여기시 발생하는 가열(heatup from energization)로 인해 수명이 단축되는 영향이 서비스 수명 기간에 적절하게 포함되지 않았기 때문에 발생되었다 많은 발전소 운용자는 이러한 사실을 알고 있지 못하였으며 결과적으로 서비스 수명 기간이 과도 예측되는 결과가 초래되었다 SOV의 또 다른 연성(Soft) 봉인물질로, 열저항 특성이 EPDM에 비해 약 $50^{\circ}C$ 정도 우수한 Viton 봉인물질에 대한 특성이 제시되었다. 더불어 현재 많은 국외 솔레노이드구동밸브 전문 생산업체들이 Viton 재료를 옵션으로 채택하고 있는 추세이다. 그러나 고온주변에서 지속적으로 노출되어 있는 환경에서 Viton이 EPDM의 문제점을 어느 정도 해결할 수 있는 지의 여부는 현재 결론 내리기 어려울 것으로 판단되며, 향후 이를 채택한 SOV의 운전경험을 계속 주시할 필요가 있을 것으로 판단된다.

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Support-area Dependence of Vibration-insensitive Optical Cavities

  • Lee, Won-Kyu;Park, Sang Eon;Park, Chang Yong;Yu, Dai-Hyuk;Heo, Myoung-Sun;Kim, Huidong
    • Current Optics and Photonics
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    • v.3 no.2
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    • pp.128-134
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    • 2019
  • The vibration sensitivities of optical cavities depending on the support area were investigated, both numerically and experimentally. We performed numerical simulations with two models: one with total constraint of the support area, and the other with only vertical constraint. An optimal support condition insensitive to the support's area could be found by numerical simulation. The support area was determined in the experiment by a Viton rubber pad. The vertical, transverse, and longitudinal vibration sensitivities were measured experimentally. The experimental result agreed with the numerical simulation of a sliding model (only vertical constraint).

A Study on the Reliability Evaluation System for O-ring of Semiconductor Equipments (반도체장비용 오링의 종합 신뢰성 평가기술에 관한 연구)

  • 김동수;김광영;최병오;박화영
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.613-617
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    • 2001
  • The test items like as endurance, air leakage and oil endurance test is requested for reliability evaluation about O-ring which is a kind of core machinery accessories of semi-conduct manufacturing equipment. For verification of these, we design and manufactured a test system for endurance, air leakage and oil endurance of O-ring for semi-conduct manufacturing equipment, and also performed the test for two kinds of O-ring, as it were Viton and Kalretz. The characteristics of this test equipment consist in realization of the test conditions of semi-conduct manufacturing equipment and satisfying the test method. The test conditions are cut gas, vacuum grade, temperature and revolution numbers in the endurance test system, vacuum grade and temperature in the air leakage test system, temperature and time in the oil endurance test system. The separating test results for wearing which is an oil endurance test item, the wearing index of domestic produced Viton O-ring is higher than foreign product by 2%, wearing rate of Kalretz O-ring better than Viton O-ring by 17%, and particles existed in various place. The test result of air leakage which is measured through the RGA sensor used Helium, the vacuum grade was $10^-3$Torr. And the test result of oil endurance, the volume change rate was 7~15%. Hereafter, we intend to analysis the reliability test evaluation and to utilize for domestic manufacturing companies by establishing data base and developing reliability softwares.

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The Characteristic Analysis and the Manufacture of Explosive THPP on PMD (PMD용 화약 THPP 제조 및 특성분석)

  • Kim, Sangbaek;Shim, Jungseob;Ahn, Gilhwan;Kim, Junhyung;Ryu, Byungtae
    • Journal of the Korean Society of Propulsion Engineers
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    • v.20 no.5
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    • pp.84-89
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    • 2016
  • THPP(Titanium Hydride Potassium Perchlorate) is an igniter composed of potassium perchlorate as oxidizing agent and titanium hydride as fuel with a Viton binder. THPP is commonly found in the aerospace, defence and automotive industries. This research is investigeted for the manufacturing process and characteristics analysis of the THPP such as the performance and shape/calorimetry/pressure characteristics of the THPP on PMD(Pyrotechnic Mechanical Device). Also, THPP composite ratio is designed by CEA program.