• Title/Summary/Keyword: thermal stress improvement

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The Characteristics Analysis of Novel Moat Structures in Shallow Trench Isolation for VLSI (초고집적용 새로운 회자 구조의 얕은 트랜치 격리의 특성 분석)

  • Lee, Yong-Jae
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.10
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    • pp.2509-2515
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    • 2014
  • In this paper, the conventional vertical structure for VLSI circuits CMOS intend to improve the stress effects of active region and built-in threshold voltage. For these improvement, the proposed structure is shallow trench isolation of moat shape. We want to analysis the electron concentration distribution, gate bias vs energy band, thermal stress and dielectric enhanced field of thermal damage between vertical structure and proposed moat shape. Physically based models are the ambient and stress bias conditions of TCAD tool. As an analysis results, shallow trench structure were intended to be electric functions of passive as device dimensions shrink, the electrical characteristics influence of proposed STI structures on the transistor applications become stronger the potential difference electric field and saturation threshold voltage, are decreased the stress effects of active region. The fabricated device of based on analysis results data were the almost same characteristics of simulation results data.

Study on Crack Resistance Improvement of Epoxy Insulation (Epoxy 절연물의 내크랙성 향상에 관한 연구)

  • Ha, Young-Kil;Kim, Su-Yon;Lee, Sang-Jin;Kim, Young-Seong;Park, Wan-Ki
    • Proceedings of the KIEE Conference
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    • 1999.07d
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    • pp.1581-1583
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    • 1999
  • Epoxy Compound has been used as insulation material in cable accessories. During the applying voltage to cable, heat shock is induced to accessory by the temperature difference between atmosphere and conductor. In this study, crack resistance, thermal and mechanical properties were evaluated about conventional epoxy compound and rubber toughened epoxy compound. Because rubber absorbs the stress caused by heat shock, crack resistance of rubber toughened epoxy compound is high. In the case of low thermal expansion coefficient, the compound shows high crack resistance because of low volumetric change.

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The Study on Improvement in Subcooling of TMA Clathrate for PCM in Ice Storage System (빙축열시스템 PCM용 TMA-포접화합물의 과냉도 개선에 대한 연구)

  • Kim, J.H.;Chung, N.K.;Kim, C.O.
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.1663-1666
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    • 2003
  • TMA clathrate that is used by PCM of ice storage system in this research creates hydrate crystallization at higher temperature than pure water, and application is expected as PCM because having comparative big dormant temperature without phase separation phenomenon. In case this research uses TMA clathrate by PCM, choose admixture by purpose to control or remove subcooling of TMA clathrate and evaluated experimentally. Subcooling is improved and can expect contraction of freezing machine running time and increase of coefficient of performance as that add admixture to TMA clathrate conclusively. Also, may supply thermal storage system that apply low temperature potential heat thermal storage material that subcooling is improved more extensively laying stress on medium size building and small size building, can expect allowance through localization of ice storage system.

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Potentials of Phyllanthus amarus, Viscum album and Moringa oleifera supplements to mitigate heat stress in female rabbits in humid tropics

  • Olatunji Abubakar Jimoh;Blessing Oluwaseun Olakanye;Ayoola Mercy Ajewole;Saanu Olajumoke Akinbuyide;Johnson Sunday Adetifa;Abdul-Quadri Ayodeji Jimoh;Adewale Oluwatosin Mayowa;Feyisayo Pemisire Adesina
    • Journal of Animal Science and Technology
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    • v.66 no.1
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    • pp.79-92
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    • 2024
  • Global warming is a key challenge subjecting animals to heat stress conditions resulting in multiple physiological alterations in tropical climate. Dietary approach seems to be the more friendly approach to curb the adverse effects of heat stress in rabbits. Some herbs have been categorized to have high potential for promotion of immune responses for amelioration of heat stress. Thus, this research aims to evaluate the potential of Mistletoe (Viscum album), Moringa (Moringa oleifera) and Phyllanthus (Phyllanthus amarus) leaf meal as herbal supplements for the alleviation of heat stress in female rabbits by measuring improvement in sex and stress hormonal responses in serum biochemistry. 80 Rabbit does were exposed to 4 dietary groups supplemented with each of Mistletoe, Moringa, Phyllanthus and a control in an 84-day trial at the summit of thermal stress in South west Nigeria. Growth indices were monitored throughout the study, blood samples were compiled at the end of the trial to assess serum biochemistry, stress and sex hormonal responses of the Does using standard protocols. The results revealed that final weight and weight gain of Does fed on Phyllanthus were significantly (p < 0.05) higher (11.46% and 14.25%, respectively) than Does on control. The herbal supplements enhance glucose, protein, albumin and globulin, reduced cholesterol, and creatinine of Does under heat stress conditions. Among the herbal treatment groups, mistletoe, moringa and phyllanthus had 12.42%, 18.39% and 16.90%, respectively, lower corticosterone than control groups which had 39.76ng/ml. Triiodothyronine of Does fed control were significantly (p < 0.05) lower than Does on Moringa oleifera and Phyllanthus amarus supplements. Estradiol and Follicle stimulating hormone of rabbit Does fed on moringa supplement were significantly (p < 0.05) higher than other treatments. In conclusion, the herbal supplements tend to mitigate the detrimental outcome of thermal stress on Does by suppressing stress hormones. Moringa oleifera and Phyllanthus amarus enhanced sex hormones while Phyllanthus amarus confered growth promoting effects on the Does.

Improvement of Device Characteristic on Solution-Processed InGaZnO Thin-Film-Transistor (TFTs) using Microwave Irradiation

  • Moon, Sung-Wan;Cho, Won-Ju
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.15 no.2
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    • pp.249-254
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    • 2015
  • Solution-derived amorphous indium-gallium-zinc oxide (a-IGZO) thin-film-transistor (TFTs) were developed using a microwave irradiation treatment at low process temperature below $300^{\circ}C$. Compared to conventional furnace-annealing, the a-IGZO TFTs annealed by microwave irradiation exhibited better electrical characteristics in terms of field effect mobility, SS, and on/off current ratio, although the annealing temperature of microwave irradiation is much lower than that of furnace annealing. The microwave irradiated TFTs showed a smaller $V_{th}$ shift under the positive gate bias stress (PGBS) and negative gate bias stress (NGBS) tests owing to a lower ratio of oxygen vacancies, surface absorbed oxygen molecules, and reduced interface trapping in a-IGZO. Therefore, microwave irradiation is very promising to low-temperature process.

Effect of alpha-tocopheryl acetate, retinyl palmitate, and phytantriol on hair protection

  • Ki Young Ahn;Hong Jong Song;Dong Chung Kim
    • Journal of Applied Biological Chemistry
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    • v.65 no.4
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    • pp.307-312
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    • 2022
  • A hair essence containing α-tocopheryl acetate, retinyl palmitate, and phytantriol (TRP-hair essence) was prepared. TRP-hair essence was excellent in thermal stability to the extent that it did not harden at all even at 210 ℃. TRP-hair essence potently protected the hair from heat stress, significantly reducing the protein leakage in heat-treated hair (p <0.001). Treatment of TRP-hair essence to dyed human hair significantly protected hair against heat stress (p <0.05) as well as improved hair cuticle and color persistence (p <0.05). In addition, as a result of directly treating human hair with TRP-hair essence, the cuticle and tensile strength of human hair were significantly improved (p <0.05). These results suggest that TRP-hair essence can be effective for hair protection and hair quality improvement.

A Study on Optimization of Thermophysiological Indices for Harbor Workers in Summer: Improvement of MENEX Model's Input Data Considering the Work Environment (하계 항만열환경지수 최적화 방안연구: 항만작업환경을 반영한 MENEX모델의 입력변수 개선)

  • Yun, Jinah;Hwang, Mi-Kyoung;Kim, Yoo-Keun
    • Journal of Environmental Science International
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    • v.25 no.7
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    • pp.951-961
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    • 2016
  • To prevent increasing instances of heat-related illnesses due to heat waves generated by climate change, a customized thermal environment index should be developed for outdoor workers. In this study, we conducted sensitivity analysis of the Masan harbor during a heat wave period (August 9th to 15th, 2013) using the MENEX model with metabolic rate and clothing-insulation data, in order to obtain realistic information about the thermal environment. This study shows that accurate input data are essential to gather information for thermophysiological indices (PST, DhR, and OhR). PST is sensitive to clothing insulation as a function of clothing. OhR is more sensitive to clothing insulation during the day and to the metabolic rate at night. From these results, it appears that when exposed to high-temperature thermal environments in summer, wearing highly insulated clothing and getting enough rest (to lower the metabolic rate) can aid in preventing heat-related illnesses. Moreover, in the case of high-intensity harbor work, quantification of allowed working time (OhR) during heat waves is significant for human health sciences.

Dielectrical Characteristics of Ultrathin Reoxidized Nitrided Oxides by Rapid Thermal Process (급속 열처리 공정에 의한 초박막 재산화 질화산화막의 유전 특성)

  • 이용재;안점영
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.16 no.11
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    • pp.1179-1185
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    • 1991
  • Ultrathin Reoxidized Nitrided Oxides were formed by lamp heated rapid thermal annealing in oxyzen at temperatures of $1050^{\circ}C$-$1100^{\circ}C$ for 20, 40 seconds. The electrical characteristics of ultrathin films were evaluated by leakage current breakdown voltage. TDDB. FN tunneling. Nitridation and reoxidition condition dependence of charge trapping properties. i.e.. the flat band voltage shift $({\Delta}V_{FB})$ and the increase of charge-to-breakdown $(Q_{BD})$ induced by a high field stress where studied. As the results of analysis. rapid thermal reoxidation was achieved striking improvement of dielectric integrity, the charge to breakdown was increased and flat band voltage shift was reduced.

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Improvement in Long-term Stability of Pd Alloy Hydrogen Separation Membranes (팔라듐 합금 수소분리막의 내구성 향상)

  • Kim, Chang-Hyun;Lee, Jun-Hyung;Jo, Sung-Tae;Kim, Dong-Won
    • Journal of the Korean institute of surface engineering
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    • v.48 no.1
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    • pp.11-22
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    • 2015
  • Pd alloy hydrogen membranes for hydrogen purification and separation need thermal stability at high temperature for commercial applications. Intermetallic diffusion between the Pd alloy film and the porous metal support gives rise to serious problems in long-term stability of Pd alloy membranes. Ceramic barriers are widely used to prevent the intermetallic diffusion from the porous metal support. However, these layers result in poor adhesion at the interface between film and barrier because of the fundamentally poor chemical affinity and a large thermal stress. In this study, we developed Pd alloy membranes having a dense microstructure and saturated composition on modified metal supports by advanced DC magnetron sputtering and heat treatment for enhanced thermal stability. Experimental results showed that Pd-Cu and Pd-Ag alloy membranes had considerably enhanced long-term stability owing to stable, dense alloy film microstructure and saturated composition, effective diffusion barrier, and good adhesive interface layer.

DURABILITY IMPROVEMENT OF A CYLINDER HEAD IN CONSIDERATION OF MANUFACTURING PROCESS

  • Kim, B.;Chang, H.;Lee, K.;Kim, C.
    • International Journal of Automotive Technology
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    • v.8 no.2
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    • pp.243-248
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    • 2007
  • The durability of a cylinder head is influenced by the thermal and mechanical history during the manufacturing process, as well as engine operation. In order to improve the durability of cylinder head, both load from engine operation and the preload conditions from the manufacturing process must be considered. The aluminum cylinder head used for a HSDI diesel engine is investigated to reduce the possibility of high cycle fatigue crack in this study. FE analysis is performed to elucidate the mechanism of high cycle fatigue crack in the HSDI diesel cylinder head. Two separate approaches to increase the durability of the cylinder head are discussed: reducing load from engine operation and re-arranging preload conditions from the manufacturing process at the critical location of the cylinder head. Local design changes of the cylinder head and modification of pretension load in the cylinder head bolt were investigated using FE analysis to relieve load at the critical location during engine operation. Residual stress formed at the critical location during the manufacturing process is measured and heat treatment parameters are changed to re-arrange the distribution of residual stress. Results of FE analysis and experiments showed that thorough consideration of the manufacturing process is necessary to enhance the durability of the cylinder head.