• 제목/요약/키워드: Alternating Temperature

검색결과 201건 처리시간 0.025초

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

  • Habib, K.
    • Corrosion Science and Technology
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    • 제4권6호
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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.

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

  • 김진선
    • Child Health Nursing Research
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    • 제22권2호
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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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    • 제13권5호
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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.

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

  • 양학희;박종성
    • 한국표면공학회지
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    • 제41권1호
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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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    • 제8권2호
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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.

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

  • 김진석;황인택;홍경식;조광연
    • 한국잡초학회지
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    • 제7권3호
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    • pp.257-264
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    • 1987
  • 큰달맞이꽃 종자(種子)의 발아(發芽)에 관계 되는 광(光)이외의 주요인자(主要因子)들을 알기 위하여 일차적(一次的)으로 암발아(暗發芽)에 영향(影響)을 미치는 요인(要因)들을 조사(調査)하여본 결과(結果)는 다음과 같았다. 여러가지의 물이적변화유기처리(物理的變化誘起處理)는 항온(恒溫) 암조건(暗條件)에서 발아(發芽)되지 않았던 종자(種子)의 암발아(暗發芽)을 유기(誘起)시켰다. $15{\sim}40^{\circ}C$의 항온(恒溫)에서는 암발아(暗發芽)되지 않았으나 $4^{\circ}C$의 저온(低溫), $-10^{\circ}C$의 냉동 또는 $80^{\circ}C$의 고온처리(高溫處理)에서는 암발아(暗發芽)가 유기(誘起)되었다. 변온(變溫)은 암발아(暗發芽)를 유기(誘起)시켰으며 $10{\sim}25^{\circ}C$ 범위(範圍)에서는 적어도 $5^{\circ}C$ 이상의 변온폭(變溫幅)을 요구하였다. 변온에 대한 종자(種子)의 감응(感應)은 치상후 1~2일째 이루어졌다. $GA_3$, IAA, BA, Ethrel은 암발아(暗發芽)에 유기효과(誘起效果)가 없었으나 Thiourea 처리는 1.0% 농도처리에서 40%의 암발아(暗發芽)를 유기(誘起)시켰다.

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

  • 강진호;강신윤;전병삼
    • 한국자원식물학회지
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    • 제13권1호
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    • pp.18-24
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    • 2000
  • 현재 국내에서 시판되고 있는 어린 묘 중에서 가장 판매주수가 많은 것이 고추 묘로서 부가가치를 더욱 높이기 위하여는 발아와 균일성을 향상시켜야 할 것이다. 본 연구의 목적은 발아와 균일성 향상에 효과가 있는 priming 처리중의 광질처리와 발아온도에 따른 발아율의 변화를 추적하여 고추 공정묘 생산에 필요한 정보를 제공하고자 실시하였다. 대명고추 [(주)중앙종묘]와 왕고추[(주)동부한농종묘]를 공시품종으로 파종 전처리는 priming 제 [KNO$_3$; Ca(NO$_3$)$_2$], 농도 (0, 150, 300 mM), 처리기간 (0, 6, 12일), 광질 (적색, 초적색, 청색, 암)과 발아과정에서는 온도 (15, $25^{\circ}C$ 항온, 25/15$^{\circ}C$ 변온)를 달리하여 발아과정에서는 백열등으로 조사하면서 시험을 수행하였다. 시험결과를 요약하면 다음과 같다. 1. Priming제로서는 KNO$_3$보다는 Ca(NO$_3$)$_2$가 발아율을 향상시켰으며 최종발아율과 T$_{50}$은 공시품종 모두 Ca(NO$_3$)$_2$로 6~12일간 priming 처리하는 것이 처리하지 않는 것보다는 각각 증가되거나 짧아지는 경향을 보였다. 2. 발아온도 $25^{\circ}C$ 항온에서 파종 후 5일까지는 암상태에서 priming한 것에서 발아율이 가장 높았으나 파종 7일 이후에는 초적색광을 조사하면서 priming할 경우 가장 낮았다. 3. 발아율은 $25^{\circ}C$ 항온에서 가장 높고 15$^{\circ}C$ 항온에서는 현저히 억제되었으나 25/15$^{\circ}C$ 변온에서의 최종발아율은 $25^{\circ}C$ 항온에 근접하거나 동일한 것으로 나타났다. 4. 각 공시품종의 발아율은 priming 유무, priming 중에 처리되는 광질과 발아온도에 따라 변화되었으며 발아온도를 달리할 경우 파종 7일 후부터 priming중 적색광 처리시 발아율이 가장 높아 priming중의 광질효과도 발아온도의 영향을 받는 것으로 나타났다.

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

  • 유권상;김용일;남승훈;유광민;조육;손대락
    • 비파괴검사학회지
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    • 제20권5호
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    • pp.445-450
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    • 2000
  • 고온에서 운용 중인 설비의 안전성을 평가하기 위해서는 사용기간동안 열화된 재료의 물성을 측정하여야 한다. 실제 사용되고 있는 화력발전소 터빈의 로터에서 열화도가 다른 여러 종류의 시편을 입수하기 어렵기 때문에, 터빈 로터재로 널리 사용되고 있는 1Cr-1Mo-0.25V 강을 인공열화시켜 시편으로 사용하였다 열화도의 비파괴적 평가를 위하여 교류 섭동 자기장을 인가하여 가역 투자율을 측정하는 자기적 방법을 사용하였다. 열화도의 증가에 따라 경도와 가역 투자율 피크 사이의 간격은 감소하였는데, 경도와 가역 투자율 피크 간격과의 선형관계를 이용하여 비파괴적으로 터빈 로터강의 열화도를 평가할 수 있는 기초를 마련하였다.

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

  • 조종택
    • 한국응용곤충학회지
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    • 제14권4호
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    • pp.205-208
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    • 1975
  • 딸기 반엽병균의 균주별 분생포자 형성과 균계생장에 미치는 광선과 온도의 영향을 조사하었다. 1. 분생포자 형서엥 미치는 광선과 온도의 영향은 모든 균주가 다 같이 선광과 온도간의 교호작용에 유의성이 있었다. 즉 저온에서는 광선이 분생포자 형성을 촉진하나 고온에서는 광선이 억제효과를 나타내었다. 그러나 $22^{\circ}C$에서는 모든 균주의 분새포자 형성에 광암교호의 효과가 높았고 $15^{\circ}C$에서는 균주 $Su_1$을 제외하고는 광암교호처리의 효과를 나타내었다. 2)균계생장량은 광선과 온도간의 교호작용에는 유의성이 없었으나 균주별로는 $S_3$$K_2,\;S_4,\;Su_1$에 비하여 생장량이 가장 많았고 온도별로는 $22^{\circ}C$에서 균계생장량이 가장 많았다.

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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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    • 제8권2호
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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.