• Title/Summary/Keyword: Temperature stability time

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Study for thermal stability of Liquid Crystal Device (액정 소자의 열적 안전성에 관한 연구)

  • Lee, Sang-Keuk;Hwang, Jeoung-Yeon;Seo, Dae-Shik;Lee, Joon-Ung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.04a
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    • pp.9-12
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    • 2004
  • In this study, we investigated about electrooptics characteristic of three kind of TN cell on the polyimide surface. Monodomain alignments of thermal stressed TN cell over temperature of liquid crystal isotropic phase were almost same that of no thermal stressed TN cells. However, the thermal stressed TN cell have many defects. Also, threshold voltage and response time of thermal stressed TN cells show same performances of no thermal stressed TN cells. There were little changes of value in these TN cells. However, transmittances of TN cells on the polyimide surface decrease with increasing thermal stress time. Finally, the residual DC voltage of the thermal stressed TN cell on the polyimide surface show decrease of characteristics as increasing thermal stress time. Therefore, thermal stability of TN cell was decreased by high thermal stress for the long times.

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Effect of Electro-stimulation on Stability of Alcohol Dehydrogenase from Horse Liver (알콜 탈수소효소의 안정도에 미치는 전기 자극의 효과)

  • Lee Kang-Min;Kim Chunl-Sang;Lee Hye-Jung;Hahm Dae-Hyun;Park Chung-Ung
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.18 no.6
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    • pp.1723-1727
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    • 2004
  • We investigated the activity and stability of alcohol dehydrogenase from horse liver (HLADH) under the electric stimulation. The activity and stability of alcohol dehydrogenase depended on electric output voltaqe, stimulation time, pulse duration and pulse interval, and temperature. HLADH retained about 23% of its activity in buffer but 78% in 10% trehalose solution under electric stimulation with 10V, 10min, The stabilizing of enzymes against electric stimulation by stabilizing additives showed a great potential use of enzymes in biotechnology and medical engineering fields.

A study on the stability of turbulent diffusion flame in double swirl flows (이중선회류중의 난류확산화염의 안정화에 관한 연구)

  • 조용대;최병륜
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.14 no.6
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    • pp.1669-1678
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    • 1990
  • The annular and coaxial swirl flows between which LPG is supplied was selected to study the swirling flames in double co-swirl flows. The objective of this study is to research into the effects of double co-swirl flow conditions on the stability limit, the reverse flow boundary, and the time mean temperature distributions of the swirling flames. The increase of swirl intensity of axial flow makes the stability limit decrease, but the annular swirl flow (SM>0.5) makes stability and swirl intensity of axial flow increase, And the existence of axial swirl flow makes flame intensive and small in size, and this may be applicable to the design of high power compact combustor.

Fatty Acid Composition and Stability of Extracted Mackerel Muscle Oil and Oil-Polyethylene Glycol Particles Formed by Gas Saturated Solution Process

  • Haque, A.S.M. Tanbirul;Asaduzzaman, A.K.M.;Chun, Byung-Soo
    • Fisheries and Aquatic Sciences
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    • v.17 no.1
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    • pp.67-73
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    • 2014
  • The oil in mackerel muscle was extracted using an environment friendly solvent, supercritical carbon dioxide (SC-$CO_2$) at a semibatch flow extraction process and an n-hexane. The SC-$CO_2$ was maintained at a temperature of $45^{\circ}C$ under pressures ranging from 15 to 25 MPa. The flow rate of $CO_2$ (27 g/min) was constant during the entire 2 h extraction period. The fatty acid composition of the oil was analyzed using gas chromatography (GC). Significant concentrations of eicosapentaenoic acid (EPA) acid and docosahexaenoic acid (DHA) acid were present in the SC-$CO_2$ extracted oil. The oil extracted using SC-$CO_2$ exhibited increased stability compared with n-haxane extracted oil. Particles of mackerel oil together with the biodegradable polymer, polyethylene glycol (PEG) were formed using a gas saturated solution process (PGSS) with SC-$CO_2$ in a thermostatted stirred vessel. Different temperatures ($45-55^{\circ}C$), pressures (15-25 MPa) and a nozzle size $400{\mu}m$ were used for PGSS with a 1 h reaction time. The stability of mackerel oil in the particles did not changed significantly.

Stability Improvement of CdTe Solar Cells using ZnTe:Na Back Contact (Na 도핑된 ZnTe 후면전극을 이용한 CdTe 태양전지의 안정성 개선에 관한 연구)

  • Cha, Eun Seok;Park, Kyu Charn;Ahn, Byung Tae
    • Current Photovoltaic Research
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    • v.3 no.1
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    • pp.10-15
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    • 2015
  • Cu doping by copper or $Cu_2Te$ materials enhances p+ formation in CdTe near the back contact interface, allowing better formation of ohmic contact. However, the Cu in CdTe junction is also considered as a principal component of CdTe cell degradation. In this paper, Na-doped ZnTe layer was employed as a back contact material to improve the stability of CdTe solar cells. As a process variable, post $CdCl_2$ treatment of CdS/CdTe film was conducted before or after depositing ZnTe:Na on CdTe. The change of the photovoltaic properties of CdTe cells were investigated with aging time. Low-temperature photoluminescence analysis was conducted to describe the degradation mechanism. The result showed that the CdTe solar cells with better stability compare to Cu contact were achieved using an optimized ZnTe:Na back contact.

The Effects of Kangaroo Care on Maternal Self-esteem and Premature Infants' Physiological Stability

  • Lee, Ji-Hye;Bang, Kyung-Sook
    • Women's Health Nursing
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    • v.17 no.5
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    • pp.454-462
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    • 2011
  • Purpose: This paper identified the effects of kangaroo care (KC) on maternal self-esteem and the growth and physiological stability of premature infants hospitalized in the neonatal intensive care unit. Methods: The experiment was conducted with an experimental group of 17 infants, and a control group of 17 infants selected by convenience sampling. KC was given to the infants one time a day for 30 minutes after feeding for two weeks. Their weight was measured every morning, and their physiological stability was measured in terms of their body temperature, respiratory rate, heart rate, oxygen saturation, and stability of the cardio-respiratory system in premature infants (SCRIP) score, as physiological responses at every 10 minutes during the intervention. Maternal self-esteem was assessed by a maternal self-report inventory. Results: The experimental group showed significant increase in the self-esteem of mothers. Also, KC was effective on physiological stabilization of preterm infants. Conclusion: This study suggests that KC can be provided in clinical settings more widely in Korea as one of the nursing interventions aimed at promoting maternal self-esteem as well as infants' physiological stabilization.

Effect of Cross-Linking Characteristic on the Physical Properties and Storage Stability of Acrylic Rubber

  • Seong-Guk Bae;Min-Jun Gim;Woong Kim;Min-Keun Oh;Ju-Ho Yun;Jung-Soo Kim
    • Elastomers and Composites
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    • v.58 no.3
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    • pp.136-141
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    • 2023
  • Polyacrylic rubber (ACM) is well known for its excellent heat resistance and chemical stability. Additionally, its performance can be readily manipulated by modifying its functional groups, rendering it highly attractive to various industries. However, extreme climate changes have necessitated an expansion of the operating temperature range and lifespan of ACM products. This requires the optimization of both the compounding process and functional-group design. Hence, we investigated the relationship between the cross-linking system and mechanical properties of an ACM with a carboxylic cure site. The crosslink density is determined by chemical kinetics according to the structure of additives, such as diamine crosslinkers and guanidine accelerators. This interaction enables the manipulation of the scotch time and mechanical properties of the compound. This fundamental study on the correlation analysis between cross-linking systems, physical properties, and storage stability can provide a foundation for material research aimed at satisfying the increasingly demanding service conditions of rubber products.

Study on the Storage Stability of Horse Fat in Jeju (제주산 말지방(Horse Fat)의 저장 안정성 향상에 관한 연구)

  • Kim, Mi Seon;Yoon, Kyung-Sup
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.46 no.1
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    • pp.31-42
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    • 2020
  • Horse fat is known to be an effective ingredient in Asia, and the horse fat itself, which is mixed with other ingredients at the additive level, is often sold as a finished product. In this case, physical properties of the horse fat raw material are important. Many horse fats produced in Korea (Jeju) have low temperature stability, so if not stored at low temperatures, segregation may occur. In the case of Japanese horse fat, it is partially hydrogenated or is used the solid phase as the horse fat by separating the liquid phase and the solid phase that is harder and more stable than the horse fat of Jeju. In this study, the physical properties were tested to improve the temperature stability even without the partial hydrogenation process of Jeju horse fat. Various oil gelling agents were used in the study. Results confirmed that the physical properties of the hydroxystearic acid added Jeju horse fat were improved. In addition, stability evaluations at temperatures of 25 ℃, 40 ℃, 45 ℃ and flow behavior evaluations at temperatures of 25 ℃, 30 ℃, 40 ℃ were performed for Jeju horse fat with hydroxystearic acid, 100% Jeju horse fat, and 100% Japanese horse fat. Results showed that the Jeju horse fat improved in flow behavior by adding hydroxystearic acid similar to that of Japanese horse fat. In addition, when the crystal state was observed under a microscope, the thermal stability was improved by decreasing the size of the needle-type crystals with the addition of hydroxystearic acid. Jeju horse fat containing hydroxystearic acid was found to have no physical problems even when stored at room temperature for a long time.

Core Temperature Evaluation in Different Body Parts in Patients Undergoing Laparoscope Surgery under Total Intravenous Anesthesia (전정맥 전신마취하(下) 복강경 수술환자의 부위별 심부체온의 변화 평가)

  • Hahm, Tae Soo;Kim, Won Ho;Kim, Nam Cho;Yoo, Je Bog
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.22 no.4
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    • pp.379-386
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    • 2015
  • Purpose: The trend of body temperature change during laparoscopic surgery and the most adequate site for monitoring temperature measurements have not been investigated thoroughly. In this study body temperature change during laparoscopic surgery was measured and measurements of the tympanic, esophageal, and nasopharyngeal core temperatures in surgical patients with total intravenous anesthesia were compared. Methods: From February to October 2013, 28 laparoscopic surgical patients were recruited from a tertiary hospital in Seoul. The patients' core temperature was measured 12 times at ten minute intervals from ten minutes after the beginning of endotracheal intubation. Results: Repeated measure of core temperatures indicated a significant difference according to body part (p=.033), time of measure (p<.001) and the reciprocal interaction between body part and time of measure (p<.027). The core temperatures were highest at tympany location, lowest at nasopharynx. The amount of temperature change was least for the esophagus ($36.10{\sim}36.33^{\circ}C$), followed by nasopharynx and tympany. Conclusion: The esophageal core temperature showed the highest stability followed by nasopharyngeal and tympanic temperature. Therefore, close observations are required between 10~20minutes after the beginning of the operation.

The improvement of the stability of hydrogenated amorphous silicon (수소화된 비정질 실리콘박막의 안정성향상에 관한 연구)

  • 이재희
    • Journal of the Korean Vacuum Society
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    • v.8 no.1
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    • pp.51-54
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    • 1999
  • Hydrogenated amorphous silicon (a-Si:H) films are fabricated by Argon radical annealing (ArRA). The deposition rate of continuously deposited a-Si:H film is 1.9 $\AA$/s. As ArRA time are increased to 0.5 and 1 minute, the deposition rate are increased to 2.8 $\AA$/s and 3.3 $\\AA$/s. The deposition rate of a-si:H films with 2 and 3 minutes ArRA time are 3.3 $\AA$/s. As the ArRA time is increased, the optical band gap and the hydrogen contents in the a-Si:H films are increased and slightly decreased. The light-induced degradation of ArRA treated a-Si:H films are less than that of continuously deposited a-Si:H film. The dark conductivity and the conductivity activation energy ($E_a$) of continuously deposited a-Si:H film are decreased to 1/25 in room temperature and increased to 0.09eV By 1 hour light soaking, respectively. The dark conductivity and $E_a$ of ArRA treated a-Si:H film decreased to 1/3 in room temperature and increased to 0.03eV by 1 hour light soaking, respectively. We could improve the stability of a-Si:H films under the light soaking by ArRA technique and discussed the microscopic process of ArRA technique.

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