• 제목/요약/키워드: aging effect

검색결과 2,537건 처리시간 0.026초

PVA/PAM 막의 aging effect (Aging effect of poly(vinyl alcohol) membranes with poly(acrylic acid-co-maleic acid))

  • Hwang, Ho-Sang;Kim, Dae-Sik;Park, Ho-Bum;Rhim, Ji-Won;Lee, Young-Moo
    • 한국막학회:학술대회논문집
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    • 한국막학회 2004년도 춘계 총회 및 학술발표회
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    • pp.195-198
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    • 2004
  • In our previous study, the crosslinked PVA/PAM membrane was prepared to investigate the pervaporation performance, and analyzed by FT-IR and water swelling test. This main objective of this work was to investigate the aging effect of PVA/PAM membrane with swelling time.(omitted)

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텅스텐이 첨가된 슈퍼 2상 스테인리스강의 내식성에 미치는 시효처리의 영향 (The Effect of Aging Treatment on the Corrosion Resistance in Super Duplex Stainless Steel with Added W)

  • 김수천;최한글;김윤규;박영태;이종문;박진환;강창룡
    • 한국해양공학회지
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    • 제23권6호
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    • pp.87-92
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    • 2009
  • The effect of aging on the precipitation of the $\sigma$ phase and the corrosion resistance in tungsten substituted super duplex stainless steels was investigated. The volume fraction of the $\sigma$ phase and the current density increased with aging at temperatures up to $750^{\circ}C$ and then decreased. With an increase in aging time, the volume fraction of the $\sigma$ phase and the current density also increased. The $\sigma$ phase hardly influenced the corrosion resistance. With the substitution of tungsten for molybdenum in super duplex stainless steel, the volume fraction of the $\sigma$ phase and the current density decreased remarkably.

18% Ni 마레이징강의 용접 잔류 응력에 미치는 열처리의 영향 (Effect of Heat Treatments on Welding Residual Stresses of 18% Ni Maraging Steel)

  • 배강열;나석주;김원훈
    • Journal of Welding and Joining
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    • 제11권2호
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    • pp.53-61
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    • 1993
  • One of the most interesting and promising steel groups considered for the rocket motor case, aircraft and aerospace component is the maraging(martensitic plus aging) nickel steel, developed by International Nickel Company in 1960. This material attains a very high strength with good fracture toughness by simple heat treatments which do not involve a quenching. Full strength can be obtained by "maraging" at 480.deg. for 3 hours for the 18% Ni maraging steel. The effect of heat treatments was considered on the residual stress field of 18% Ni maraging steel weldments. In experiments, various heat treatments such as stress relieve heat treatment, aging and solution heat treatment were carried out of the GTA weldments and the residual stresses were measured by using the hole drilling method. Whereas the conventional pattern of residual stress shows the stresses to be maximum along the weld centerline with tensile stress extending into the heat affected zone, the pattern in maraging steels shows the centerline stress to be compressive. After welding, a series of aging, solution heat treatment and solution heat treatment plus aging treatment were carried out and the residual stresses were measured to reveal that these heat treatments almost completely remove the welding residual stresses.

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슈퍼듀플렉스강 용접금속의 입계부식에 미치는 σ 상의 영향 (Effect of σ-phase on Intergranular Corrosion of Super Duplex Stainless Steel Weld Metal)

  • 이재형;정병호;서기정;강창룡
    • 열처리공학회지
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    • 제26권6호
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    • pp.293-299
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    • 2013
  • A specimen of weld metal was prepared by GTA welding with weld wire of super duplex stainless steel. Aging treatment was conducted for the sample at the temperature range of 700 to $900^{\circ}C$ for 5 to 300 minutes. The effect of volume fraction of ${\sigma}$-phase to intergranular corrosion of weld metal has been investigated and the results were derived as follows. The volume fraction of ${\sigma}$ phase tends to increase with an increase of aging temperature and time and intergranular corrosion of weld metal was increased by an increase of ${\sigma}$ phase. Degree of sensitization representing intergranular corrosion was found to tend to increase with an increase of aging time at 700 to $800^{\circ}C$, while it decreased by an increase of aging time at $900^{\circ}C$.

Factors Influencing Body Image in the Aging Process

  • Oh, Keun-Young;Damhorst, Mary Lynn
    • International Journal of Human Ecology
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    • 제9권2호
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    • pp.55-65
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    • 2008
  • This study examined the personal and relational factors influencing the formation of body image among older persons. Aging-rel£lted physical changes, health, marital relationship, cognitive age, and moods were personal and relationship factors explained for influence on the body image of older persons. Data were collected via a mail survey of older married couples residing in three US. metropolitan areas of Florida. A total of 94 married couples who were 60 years older participated in this study. Results indicated that aging-related physical changes, effect of physical changes on the self, self-assessed health, and evaluation of spouse's attractiveness, and perceived attractiveness (one's perception of the other spouse's appraisals of his or her attractiveness) were found to be significantly related to the body image of older men and women. For men, self-assessed health, evaluation of spouse's attractiveness, and perceived attractiveness were significantly related to body image while physical changes, effect of physical changes, and perceived attractiveness were found significant for women. The feelings of older persons about and satisfaction with their bodies and appearance were estimated by aging-related and relationship-related variables.

어리연꽃으로부터 분리한 Sweroside의 항노화 효과 (Anti-aging Effects of Sweroside Isolated from Nymphoides indica)

  • 김유아;김동희;박채빈;박태순;박병준
    • 대한화장품학회지
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    • 제44권2호
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    • pp.103-110
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    • 2018
  • 본 연구에서는 신규 기능성 화장품 소재 개발을 위해 어리연꽃으로부터 분리한 sweroside를 이용하여 섬유아세포 내에서의 항노화 효과를 확인하였다. CCD-986sk 세포를 이용하여 sweroside의 항노화 효과를 측정한 결과, UVB에 의해 증가된 ROS의 발현을 억제하였으며, pro-collagen의 발현을 증가시키며 MMP-1의 발현을 억제하는 것으로 확인되었다. 이 결과를 종합해보면, sweroside는 화장품 분야에서 신규 항노화 기능성 소재로서의 활용 가능성이 있는 것으로 판단된다.

대뇌피질 신경세포에 미치는 glutamate 독성에 대한 한약재 효능연구 (The effect of herbal medicine on cultured cerebral cortical neurons induced by glutamate neurotoxicity)

  • 이미영;강봉주;윤유식;홍성길;곽병주;조동욱
    • 한국한의학연구원논문집
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    • 제4권1호통권4호
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    • pp.99-114
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    • 1998
  • The effect of herbal medicine on glutamate mediated neurotoxicity was studied in mouse neurons in primary culture. Immature cerebral cortex neurons (ED14) were maintained for up to 2 weeks in vitro, and we investigated the expression pattern of neuron differentiation and cytotoxicity of cell death, including LDH activity. Neuronal maturation initiated on day 7 and the susceptibility to glutamate-induced cell death was highly sensitive on Day 11 (Fig. 1). Thus, the exposure of the neurons to glutamate caused a dose$(0.1mM{\sim}1mM)$ and time$(4h{\sim}24h)$-dependent neurotoxicity(Fig. 4). Glutamate-induced neurodegeneration was prevented by Shipchondaebotang(SD), Yollyounggobondan(YG), Yugmijihwangwon(YJ) and the death of neurons exposed to glutamate was blocked by the NMDA receptor antagonist MK-801 (Fig. 5).

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포도의 부위별 섭취가 흰쥐의 노화 과정 중 Cadmium의 대사 및 중독에 미치는 영향 (Effect of Grape Intake on Cadmium Metabolism of Rats during Aging)

  • 최서진;김미경
    • Journal of Nutrition and Health
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    • 제36권10호
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    • pp.997-1012
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    • 2003
  • This study was carried out to investigate the effect of whole grape, grape pomace and grape juice intake on cadmium (Cd) metabolism during aging in thirteen-month-old Sprague-Dawley male rats. One hundred and twenty rats weighing 548.8 $\pm$ 4.3 g were assigned to eight groups according to body weight and were raised for 3, 5 or 7 months on diets containing 2 % (w/w) dried powders of three different parts of the grape (Campbell Early) and 0.02 % (w/w) CdC12. Food intake tended to decrease with aging, and body weight and epididymal fat pad (EFP) weights of Cd-exposed groups were lower than those of Cd-free groups. Cadmium accumulated in the blood and tissues and Cd concentration was the lowest in the pomace group among Cd-exposed animals. Metallothionein (MT) concentration in the tissues increased through Cd administration. Grape diets, especially grape pomace diets, were effective in decreasing Cd absorption in the tissues by increasing Cd excretion through feces. The intake of grape pomace alleviated the decrease in bone density caused by Cd administration and prevented a decrease in glomerular filtration rates (GFR) with aging. Among the parts of grape, grape pomace, which had highest content of dietary fiber and flavonoids, was the most effective. The results of this study suggest the possibility of using grape pomace as a functional food material, a prospect that previously has been discarded.

Effect of Strain Aging on Tensile Behavior and Properties of API X60, X70, and X80 Pipeline Steels

  • Lee, Sang-In;Lee, Seung-Yong;Lee, Seok Gyu;Jung, Hwan Gyo;Hwang, Byoungchul
    • Metals and materials international
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    • 제24권6호
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    • pp.1221-1231
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    • 2018
  • The effect of strain aging on tensile behavior and properties of API X60, X70, and X80 pipeline steels was investigated in this study. The API X60, X70, and X80 pipeline steels were fabricated by varying alloying elements and thermomechanical processing conditions. Although all the steels exhibited complex microstructure consisting of polygonal ferrite (PF), acicular ferrite, granular bainite (GB), bainitic ferrite (BF), and secondary phases, they had different fractions of microstructures depending on the alloying elements and thermomechanical processing conditions. The tensile test results revealed that yielding behavior steadily changed from continuous-type to discontinuous-type as aging temperature increases after 1% pre-strain. After pre-strain and thermal aging treatment in all the steels, the yield and tensile strengths, and yield ratio were increased, while the uniform elongation and work hardening exponent were decreased. In the case of the X80 steel, particularly, the decrease in uniform elongation was relatively small due to many mobile dislocations in PF, and the increase in yield ratio was the lowest because a large amount of harder microstructures such as GB, BF, and coarse secondary phases effectively enhanced work hardening.

Wearable Sensor based Gait Pattern Analysis for detection of ON/OFF State in Parkinson's Disease

  • Aich, Satyabrata;Park, Jinse;Joo, Moon-il;Sim, Jong Seong;Kim, Hee-Cheol
    • 한국정보통신학회:학술대회논문집
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    • 한국정보통신학회 2019년도 춘계학술대회
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    • pp.283-284
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    • 2019
  • In the last decades patient's suffering with Parkinson's disease is increasing at a rapid rate and as per prediction it will grow more rapidly as old age population is increasing at a rapid rate through out the world. As the performance of wearable sensor based approach reached to a new height as well as powerful machine learning technique provides more accurate result these combination has been widely used for assessment of various neurological diseases. ON state is the state where the effect of medicine is present and OFF state the effect of medicine is reduced or not present at all. Classification of ON/OFF state for the Parkinson's disease is important because the patients could injure them self due to freezing of gait and gait related problems in the OFF state. in this paper wearable sensor based approach has been used to collect the data in ON and OFF state and machine learning techniques are used to automate the classification based on the gait pattern. Supervised machine learning techniques able to provide 97.6% accuracy while classifying the ON/OFF state.

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