• Title/Summary/Keyword: Alternating temperature

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Anodization of Aluminium Samples in Boric Acid Solutions by Optical Interferometry Techniques

  • Habib, K.
    • Corrosion Science and Technology
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    • v.4 no.6
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    • pp.217-221
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    • 2005
  • In the present investigation, holographic interferometry was utilized for the first time to monitor in situ the thickness of the oxide film of aluminium samples during anodization processes in boric acid solutions. The anodization process (oxidation) of the aluminium samples was carried out by the technique of the electrochemical impedance spectroscopy(EIS), in different concentrations of boric acid (0.5-5.0% $H_3BO_3$) at room temperature. In the mean time, the real-time holographic interferometry was used to measure the thickness of anodized (oxide) film of the aluminium samples in solutions. Consequently, holographic interferometry is found very useful for surface finish industries especially for monitoring the early stage of anodization processes of metals, in which the thickness of the anodized film of the aluminium samples can be determined without any physical contact. In addition, measurements of electrochemical values such as the alternating current (A.C) impedance(Z), the double layer capacitance($C_{dl}$), and the polarization resistance(Rp) of anodized films of aluminium samples in boric acid solutions were made by the electrochemical impedance spectroscopy(EIS). Attempts to measure electrochemical values of Z, Cdl, and Rp were not possible by holographic interferometry in boric acid especially in low concentrations of the acid. This is because of the high rate of evolutions of interferometric fringes during the anodization process of the aluminium samples in boric acid, which made measurements of Z, Cdl, and Rp are difficult.

Childhood Fever Management: Current Practice vs Evidence (아동의 발열관리: 현황 및 과학적 근거)

  • Kim, Jin Sun
    • Child Health Nursing Research
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    • v.22 no.2
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    • pp.126-136
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    • 2016
  • Purpose: The purposes of this review were to address misconceptions of childhood fever and fever management practice among parents and health care providers, and to identify the scientific evidences against such misconceptions and practices. Methods: Journal databases and clinical guidelines from 2000 to 2015 were searched. The search terms were fever, fever management, misconception, myth, fiction, fact, fever phobia, child, antipyretics, tepid bath, alternating use/combined use of antipyretics, and physical cooling method. Results: There are significant gaps between current concepts and practices, and the scientific evidence. Misconceptions and unrealistic concerns about childhood fever still exist among parents and even health care providers, worldwide. The evidences suggest that antipyretics should be given carefully with the aim of relieving discomfort or pain rather than decreasing the temperature itself. Alternating use of antipyretics should be discouraged due to the risk of confusion and error. Antipyretics do not prevent febrile convulsions. Moreover, the scientific evidence does not support tepid sponge massage. Conclusion: Evidence-based childhood fever management interventions should be targeted toward parents and health care providers. By adopting an evidence-based approach to nursing interventions, pediatric nurses can ensure children receive appropriate and safe fever management.

Synthesis and Characterization of New Blue Light Emitting Alternating Terphenylenevinylene Carbazylenevinylene Copolymer

  • Kim Yun-Hi;Park Jung-Cheol;Kang Hun-Jin;Park Jong-Won;Kim Hyung-Sun;Kim Jin-Hak;Kwon Soon-Ki
    • Macromolecular Research
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    • v.13 no.5
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    • pp.403-408
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    • 2005
  • A new terphenylenevinylene carbazylenevinylene alternating copolymer with the advantage of poly(p-phenylenevinylene) (PPV), poly(p-phenylene )(PPP) and poly(carbazole) was designed, synthesized and characterized. The polymer structure was confirmed by various spectroscopic analyses and the number average molecular weight ($M_n$) of the obtained polymer was 7,800. The resulting polymer was thermally stable with high glass transition temperature ($T_g$) ($150^{\circ}C$), and was readily soluble in common organic solvents. Cyclic voltammetry study revealed that the HOMO and LUMO energy levels of the polymer were 5.37 and 2.47 eV, respectively. The ITO/PEDOT/polymer/AI device fabricated from the polymer emitted bright sky blue light with a maximum peak of around 478 nm. The device showed the maximum brightness of 1,200 nW with a turn-on voltage of 7V.

The Effects of Anodizing Process Parameters and Oxidation Temperature under Atmospheric Environment on Morphology of the Pure Titanium by Alternating Current Arc-anodizing (순티타늄의 교류 불꽃 양극산화층 미세조직에 미치는 양극산화공정변수 및 대기산화온도의 영향)

  • Yang, Hack-Hui;Park, Chong-Sung
    • Journal of the Korean institute of surface engineering
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    • v.41 no.1
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    • pp.16-22
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    • 2008
  • Anodizing to form oxide layers on the pure titanium was performed in the electrolyte containing 1.5M $H_2SO_4$, 0.2M $H_3PO_4$, and 2.5wt.% $CuSO_4$ using the ac-biased arc anodizing technique. Titanium oxide layers anodized with different applied voltages, voltage-elevating rates, and anodizing times were investigated. In addition, thermal oxidation test under an atmospheric environment for the arc-anodized specimens was carried out. The thickness of oxide layers were not affected by the voltage-elevating rates, but increased slightly with the increase of anodizing times. The thickness of oxide layers were increased with the increase of voltages, and increased remarkably in the condition of 200V. The size and number of the pore observed in the center of the porous cell were decreased with increase of applied voltage. From the result of thermal oxidation test, it revealed that oxide layer formed by arc anodizing more effective to prevent oxidation of pure titanium.

Syntheses of Alternating Head-to-Head Copolymers of Vinyl Ketones and Vinyl Ethers, and Their Properties. Ring-Opening Polymerization of 2,3,6-Trisubstituted-3,4-dihydro-2H-pyrans

  • Lee, Ju-Yeon;Cho, I-Whan
    • Bulletin of the Korean Chemical Society
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    • v.8 no.2
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    • pp.102-105
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    • 1987
  • 2-Methoxy-6-methyl-3,4-dihydro-2H-pyran ($1_a$), 2-ethoxy-3,6-dimethyl-3,4-dihydro-2H-pyran ($1_b$), and 2-ethoxy-3-methyl-6-ethyl-3,4-dihydro-2H-pyran ($1_c$) were prepared by (4 + 2) cycloaddition reaction from the corresponding vinyl ketones and alkyl vinyl ethers. Compounds $1_{a-c}$ were ring-open polymerized by cationic catalyst to obtain alternating head-to-head (H-H) copolymers. For comparison, copolymer of head-to-tail (H-T) was also prepared by free radical copolymerization of the mixture of the corresponding monomers. The H-H copolymer exhibited some differences in its $^1H$ NMR and IR spectra. However, significant differences were showed between the H-H and H-T copolymers in the $^{13}C$ NMR spectra. Also noteworthy was that$T_g$ value of H-H copolymer was higher than that of the corresponding H-T structure. Decomposition temperature of the H-H copolymer was lower than that of the H-T copolymer. All the H-H and H-T copolymers were soluble in common solvents.

Factors Affecting Dark Germination of Oenothera lamarckiana Seeds (큰달맞이꽃 종자(種子)의 암발아(暗発芽)에 영향(影響)을 미치는 요인(要因))

  • Kim, J.S.;Hwang, I.T.;Hong, K.S.;Cho, K.Y.
    • Korean Journal of Weed Science
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    • v.7 no.3
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    • pp.257-264
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    • 1987
  • Effect of various physical and chemical treatments on dark germination of Oenothera lamarckiana seeds were primarily investigated to find out factors affecting germination. Germination of seeds which did not germinate in the constant temperature and darkness was induced by several physical treatments such as sonification, wetting and drying, freezing and thawing, and removal of seed coat. Pretreatment of chilling ($4^{\circ}C$), freezing ($-10^{\circ}C$) and incubation at high temperature ($80^{\circ}C$) induced dark germination of seeds which did not germinate in the constant temperature ranges of 15 to $40^{\circ}C$ under darkness. Alternating temperature also had a stimulatory effect on dark germination of Oenothera lamarckiana seeds. Sensing of seeds to alternating temperature appeared to be completed during the first two days after imbibition. The minimum difference of temperature required for dark germination was $5^{\circ}C$ in the range of $15-25^{\circ}C$. A thiourea (1.0%) treatment induced dark germination, but GA, IAA, BA and Ethrel failed to do so.

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Effect of Light Quality during Priming and Germination Temperature on Pepper Seed Germinability (파종 전 Priming과 광질 처리, 발아온도에 따른 고추종자의 발아율)

  • 강진호;강신윤;전병삼
    • Korean Journal of Plant Resources
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    • v.13 no.1
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    • pp.18-24
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    • 2000
  • Pepper (Capsicum annum L.) used as a spice or fruit vegetable has been transplanted for cultivation to accompany the production of its seedlings in general. The experiment was done to measure the effect of its cultivars (Daemyng; Wanggochu), priming (chemicals; concentration; period), light quality (red; far-red; blue; dark) during priming, and germination temperature (25 or 15$^{\circ}C$ constant; 25/15$^{\circ}C$ alternating) on the rate of germination done under incandescent lamps until 9 days after sowing. Seed germination was better when primed with Ca(NO$_3$)$_2$ than with KNO$_3$. Priming for 6 to 12 days using the former chemical enhanced the final germination rate and shortened the elapsed days to 50% germination, $T_{50}$, compared to no-priming. Under $25^{\circ}C$ constant germination temperature, primed seeds at darkness or far-red light showed the highest rate until 5 days after sowing or the lowest one since 7 days after sowing, respectively. The germination response at 25/15$^{\circ}C$ alternating temperature did not followed the lowest rate of 15$^{\circ}C$ constant germination temperature but inclined to that of $25^{\circ}C$ constant recorded the greatest one. Under 3 germination temperature red light treated during priming elevated the rate since 7 days after sowing compared to the other light treatments, and the germination rate of each cultivar was affected by no-priming or priming, light quality during priming. which imply their interaction to the seed germination.

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Degradation Evaluation of 1Cr-lMo-0.25V Steel by Measuring Reversible Magnetic Permeability (가역 투자율 측정에 의한 1Cr-1Mo-0.25V 강의 열화도 평가)

  • Ryu, Kwon-Sang;Kim, Yong-Il;Nahm, Seung-Hoon;Yu, Kwang-Min;Cho, Youk;Son, De-Rac
    • Journal of the Korean Society for Nondestructive Testing
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    • v.20 no.5
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    • pp.445-450
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    • 2000
  • The integrity of the turbine rotors can be assessed by measuring reversible permeability and Vickers hardness of the aged rotors at service temperature. The measurement system of reversible permeability, which measured by applied alternating perturbing magnetic field, was constructed in order to evaluate material degradation, nondestructively. The test specimen was 1Cr-1Mo-0.25V steel used widely for turbine rotor material, and the specimens were prepared by the isothermal heat treatment at $630\;^{\circ}C$. The reversible permeability of the test materials were measured at room temperature. The peak interval of reversible permeability and Vickers hardness decreased with the increase of degradation. The degradation of test material may be determined nondestructively by the lineality of Vickers hardness and the peak interval of reversible permeability.

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Effect of Light and Temperature on the Sporulation and Mycelial Growth of Mycosphaerella fragariae (딸기 반엽병균의 분생포자형성과 균사생장에 미치는 광선과 온도의 영향)

  • Cho Chong Taik
    • Korean journal of applied entomology
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    • v.14 no.4 s.25
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    • pp.205-208
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    • 1975
  • Effect of light and temperature on the sporulation and mycelial growth by 4 strains of Mycosphaerella fragariae was examined. The light source was day light fluorescent lamps with an intensity of 2000 Lux at the colony surface. The treatment were constant light, alternating light(10hr) and darness (14h.) and constant darkness af $15^{\circ}C,\; 22^{\circ}C\; and\; 30^{\circ}C$ 1. Of the 4 strains tested, alternating light and darkness at $22^{\circ}C\;and\;15^{\circ}C$ gave the greatest sroducedtion, constant light in intermediate, constant darkness in minimum, but darkness at $30^{\circ}C$ produced abundant conidia over that obtained in the other two treatment. Differences in number of sporulation due to light, strains and the interaction of these two were all statistically significant. 2. There were not on significant differences in amount of mycelial growth due to light, but amount of mycelial growth of$S_3$ strain were the nest abundant among the 4 strains.

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Syntheses of Alternating Head-to Head Vinyl Copolymers and Vinyl Terpolymers via Ring-Opening Mechanism. Ring-Opening Polymerization of Substituted-3,4-dihydro-2H-pyrans

  • Lee, Ju-Yeon;Cho, I-Whan
    • Bulletin of the Korean Chemical Society
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    • v.8 no.2
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    • pp.96-101
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    • 1987
  • 2-Ethoxy-6-methoxy-5-cyano-3,4-dihydro-2H-pyran (1_a$), 2-n-butoxy-6-methoxy-5-cyano-3,4-dihydro-2H-pyr an (1b), 2-isobutoxy-6-methoxy-5-cyano-3,4-dihydro-2H-py ran ($1_c$), and 2-ethoxy-6-methoxy-3-methyl-5-cyano-3,4-dihydro -2H-pyran ($1_d$) were prepared by (4 + 2) cycloaddition reaction of methyl $\alpha$-cyanoacrylate with the corresponding alkyl vinyl ethers. Compounds $1_{a-d}$ were ring-open polymerized by cationic catalyst to obtain alternating head-to-head (H-H) copolymers. For comparison, head-to-tail (H-T) copolymer $3_a$ was also prepared by free radical copolymerization of the corresponding monomers. The H-H copolymer exhibited minor differences in its $1_H% NMR and IR spectra, but in the $^{13}C$ NMR spectra significant differences were observed between the H-H and H-T copolymers. Glass transition temperature ($T_g$) of H-H copolymer was higher than that of the H-T copolymer, but thermal decomposition temperature of the H-H copolymer was lower than that of the H-T copolymer. Compounds $1_a$, $a_b$, and $1_c$, copolymerized well with styrene by cationic catalyst, but compound 1d failed to copolymerize with styrene. All of the H-H and H-T copolymers were soluble in common solvents and the inherent viscosities were in the range 0.2-0.4 dl/g.