• Title/Summary/Keyword: 유리 전이

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Change of Internal Temperature and Humidity According to Kind of Covering Materials in Sweet Pepper's Greenhouse (착색단고추 재배 온실의 피복재 종류에 따른 내부 온.습도 변화)

  • Kim, Ho-Cheol;Choi, Jun-Hyuk;Lee, Soo-Won;Lee, Jeong-Hyun;Bae, Jong-Hyang
    • Journal of Bio-Environment Control
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    • v.19 no.1
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    • pp.1-5
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    • 2010
  • This research was conducted to investigate difference of internal temperature, humidity, and plant growth according to covering materials in sweet pepper's greenhouse. For growing period, daily mean internal temperature was not different between glass (GH) and plastic film house (PH), but the changed volume was more PH than GH. Internal humidity deficit was more PH than GH as that was 4.3 $g{\cdot}m^{-2}$ and 5.6 $g{\cdot}m^{-2}$, respectively. In change of internal temperature effected by different intensity of external light, that of PH was fasted twice that of GH, and that's tendency was effected by difference of internal temperature for several hours after sunrise. Leaf growth and photosynthetic product were more GH than PH, productivity of GH was better 80 percents than PH. As results, To improve productivity in PH compared with productivity in GH need to be the detailed managements of internal environmental factors in early period after sunrise.

Preparation and Crystallization Kinetics of Glasses with Ferroelectric Fresnoite Crystal (강유전체 Fresnoite 결정을 갖는 유리의 제조 및 결정화 거동)

  • Lee, Hoi-Kwan;Chae, Su-Jin;Kang, Won-Ho
    • Journal of the Microelectronics and Packaging Society
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    • v.12 no.2 s.35
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    • pp.161-166
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    • 2005
  • Glass formation, thermal property and crystallization behavior were investigated in $xK_2O-(33.3-x)BaO-16.7TiO_2-50SiO_2(mole\%)$ with fresnoite($Ba_2TiSi_2O_8$) crystal by replacement BaO for $K_2O$. As x(0$\le$x$\le$20) contents increased, glass formation became easy, and crystallization temperature moved on to the low temperature. Crystal phase of the $Ba_2TiSi_2O_8$ was confirmed by XRD, and the replaced x was not effected on the formation of new crystals. The kinetics of crystallization of fresnoite were studied by applying the DTA measurements carried out at different heating rates. The average avrami exponent(n) and activation energy were changed $2.26 {\pm}0.1,\;2.03 {\pm}0.1,\;1.93{\pm}0.15$, $279 {\pm}12kJ/mole,\;302{\pm}7kJ/ mole,\;319{\pm}1kJ/mole$ according to x contents, respectively. The replaced x improved the orientation of crystal growth.

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A Case of Suprachoroidal Hemorrhage after Pars Plana Vitrectomy for Rhegmatogenous Retinal Detachment (열공망막박리 환자에서 유리체절제술 후 발생한 맥락막상강출혈 1예)

  • Kim, Min Han;Oh, Jong-Hyun
    • Journal of The Korean Ophthalmological Society
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    • v.59 no.11
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    • pp.1082-1086
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    • 2018
  • Purpose: To report a case of a 60-year-old female with rhegmatogenous retinal detachment, presenting with suprachoroidal hemorrhage after vitrectomy. Case summary: A 60-year-old woman visited our clinic complaining of floaters, flashing, and blurred vision. Best-corrected visual acuity was 0.1 in her left eye, and fundus examination of her left eye revealed macula-involved retinal detachment with a retinal break at the superotemporal quadrant. She underwent cataract surgery, 23-gauge transconjunctival sutureless vitrectomy, and 14% C3F8 gas tamponade under general anesthesia. One hour after anesthesia recovery, she suddenly complained of severe pain in her left eye. The intraocular pressure measured after removal of the pressure patch from her left eye was as high as 58 mmHg. Her ocular pain improved spontaneously within 10 minutes, and the intraocular pressure decreased to 8 mmHg. Fundus examination of her left eye revealed a reddish-brown raised lesion, suggesting suprachoroidal hemorrhage. She was placed in a prone position with a pressure patch over her left eye. Bleeding through the sclerotomy site was observed 1 day after surgery. Subsequently, hemorrhagic choroidal detachment of her left eye continued to decrease without deterioration. Three weeks after surgery, the patient received an intravitreal injection of 100% C3F8 gas into her left eye. At 3 months after surgery, best-corrected visual acuity had improved to 0.8 in her left eye, and the retina was stable. Conclusions: Suprachoroidal hemorrhage may be suspected in a patient complaining of severe ocular pain after vitrectomy.

Electrical properties of CuInSe2 thin films formed by selenization of RF sputtered Cu-In-Se2 precursors for solar cell applications (Cu-In-Se2 전구체의 Selenization에 의해 형성된 CuInSe2 박막의 태양전지 응용을 위한 전기적 특성평가)

  • Jeong, Chaehwan;Park, Chanyoung;Kim, Jinhyeok;Lee, Suk Ho
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.06a
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    • pp.79-79
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    • 2010
  • 다른 물질에 비해 많은 우수한 특성을 가지고 있는 CuInSe2(CIS)박막 태양전지는 많은 연구자들에 의해 개발되어 오고 있다. CIS의 대표적인 장점으로는 직접천이형 밴드갭, 높은 흡수계수, 열 안정화상태 및 p형으로의 전도성물질의 가능성 등 다양하다. 또한 간단한 구조를 이용하여 유리같은 싼 기판을 이용하기 때문에 저가형 태양전지로서 많은 각광을 받고 있다. CIGS태양전지는 CIS의 In 사이트에 Ga을 도핑함으로서 만들어지는데 밴드갭은 약 1.4eV이다. CIS박막을 만드는 많은 방법이 존재하나 구성원소로부터 최적화된 조성을 찾을수 있는 방법이 가장 중요한 요소 중의 하나로 인식되고 있으며, 이런점에서 증발법 및 스퍼터링법 등 같은 진공방식이 비진공방식에 비해 훨씬 간편하게 조성비를 맞출수 있다. 그 중에 스퍼터링법은 대면적 박막태양전지로의 가능성으로 비출어 볼때 산업화를 위한 좋은 후보군이 될 수 있다. Selenization을 하기전에 Cu-In-Se의 전구체 조합은 여러개의 타겟으로부터 동시 스퍼터링법이나 다층 전구체법을 사용하여 준비되는데 어떤 방법이 되던지 Se의 부가적인 공급은 불가피하다. 지금까지 많은 관련 연구의 대부분인 구조적, 조성비적 그리고 광학적인 특성평가에 집중되어 오고 있는데, 전기적특성평가의 경우는 면저항, 비저항 같은 간단한 결과 위주로 보고되어 오고 있다. 또한 캐리어농도와 이동도에 대한 보고가 있음에도 불구하고 이해되기에는 충분치 못한 면이 많다.본 발표에서는 태양전지 제조 전단계로서 소다라임유리기판(SLG)위에 Mo의 유무에 따라 CIS박막의 전기적인 특성 변화에 대한 내용을 담고 있다. 소다라임유리($2cm{\times}2cm$)를 기판으로 사용하여 아세톤-에탄올 용액에 초음파세척을 수행하고, Mo 후면전극을 DC 스퍼터링방식을 이용하여 증착을 한다. SLG와 Mo이 코팅된 SLG를 각각 RF 스퍼터 챔버에 이송한 후 수증기 제거를 위해 약 10분간 예열을 한다. 샘플에 대한 전기적특성은 Hall효과 측정장치에 의해 측정이 되며 전기전도도, 캐리어농도, 이동도 및 전도형에 대한 정보가 각각의 변수에 따라 조사된돠. 부가적으로 구조적, 조성비적인 특성을 SEM,XRD 및 EDX를 통해 조사를 하여 전기적 특성에 따른 관계성을 검토한다. SLG와 Mo가 코팅된 SLG위의 CIS박막은 전기적으로 약간 다른 특성을 보일 것으로 예측되며, 이러한 기대를 바탕으로 조성비가 이상적인 화학양론에 근접할 때 p형으로서 제시될 수 있다는 것을 보여줄 것이다.

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Stem Girding Increases Seed Production and Nitrogenous Compounds in Larix leptolepis (환상박피 처리에 의한 일본잎갈나무의 착과유도 효과와 질소 화합물 함량의 증가)

  • Lee, Wi Young;Park, Eung-Jun
    • Journal of Korean Society of Forest Science
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    • v.102 no.1
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    • pp.129-135
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    • 2013
  • Japanese larch (Larix leptolepis) has been extensively planted in Korea as a reforestation species but their supply has been a major bottleneck due to sporadic natural seed production. In this study, stem girdling was applied to 32-year-old grafted Japanese larches, resulting in significantly enhanced seed production compared to the controls. Stem girdling induced about 4 times higher cone production than that of controls in the Japanese larch seed orchard. Time-dependent metabolic alterations after girdling were investigated by stable isotope ratio mass spectrometer, HPLC, and GC-MS analysis. In girdled trees, the contents of total nitrogen, sucrose, and total free amino acids were significantly higher than the non-girdled trees at the flowering differentiation season (from July to August). Moreover, the numbers of female strobilus per tree were positively correlated with the contents of both total nitrogen (r=0.765, p<0.01) and total amino acids (r=0.802, p<0.01) in the bark being collected at the flowering differentiation time (August 20). Interestingly, the levels of various individual amino acids at the flowering differentiation times, such as aspartic acid, glutamic acid, glycine, serine, and cysteine, were also significantly correlated (p<0.05) with the numbers of strobilus, suggesting that those amino acids might be involved in the induction of female strobilus formation of Japanese larches.

Sustainable Block Copolymer-based Thermoplastic Elastomers (지속 가능한 블록 공중합체 기반 열가소성 탄성체)

  • Shin, Jihoon;Kim, Young-Wun;Kim, Geon-Joong
    • Applied Chemistry for Engineering
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    • v.25 no.2
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    • pp.121-133
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    • 2014
  • Block copolymers including ABA triblock architectures are useful as thermoplastic elastomers and toughened plastics depending on the relative glassy and rubbery content. These materials can be blended with other polymers and utilized as additives, toughening agents, and compatibilizers. Most of commercially available block copolymers are derived from petroleum. Renewable alternatives are attractive considering the finite supply of fossil resources on earth and the overall economic and environmental expenses involved in the recovery and use of oil. Furthermore, tomorrow's sustainable materials are demanding the design and implementation with programmed end-of-life. The present review focuses on the preparation and evaluation of new classes of renewable ABA triblock copolymers and also emphasizes on the use of carbohydrate-derived poly(lactide) or plant-based poly(olefins) having a high glass transition temperature and/or high melting temperature for the hard phase in addition to the use of bio-based amorphous hydrocarbon polymers with a low glass transition temperature for the soft components. The combination of multiple controlled polymerizations has proven to be a powerful approach. Precision-controlled synthesis of these hybrid macromolecules has led to the development of new elastomers and tough plastics offering renewability, biodegradability, and high performance.

Electrocatalytic Effect of Dioxygen Reduction at Glassy Carbon Electrode Modified with Schiff Base Co(II) Complexes (Schiff Base Co(II) 착물이 변성된 유리질 탄소전극에서 산소 환원의 전기촉매 효과)

  • Seong, Jeong-Sub;Chae, Hee-Nam;Choi, Yong-Kook
    • Analytical Science and Technology
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    • v.11 no.6
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    • pp.460-468
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    • 1998
  • Schiff base ligands such as $SOPDH_2$, $SNDH_2$, $EBNH_2$, and $PBNH_2$ and their Co(II) complexes such as [$Co(II)(SND)(H_2O)_2$], [$Co(II)(SOPD)(H_2O)_2$], [$Co(II)(EBN)(H_2O)$], and [$Co(II)(PBN)(H_2O)$] have been synthesized. The mole ratio of Shiff base ligand to cobalt(II) for the Co(II) complexes was found to be 1:1. Also these complexes have been configurated with hexa-coordination. Reduction of dioxygen was investigated by cyclic voltammetry at glassy carbon electrodes modified with Schiff base Co(II) complexes in 1 M KOH aqueous solution. At modified glassy carbon electrode with Schiff base Co(II) complexes, reduction peak current of oxygen was increased and peak potential was shifted to more positive direction compared to bare glassy carbon electrode. The electrokinetic parameters such as number of electron and exchange rate constant were calculated from the results of cyclic voltammogrms. The reduction of dioxygen at glassy carbon electrode has been $2e^-$ reaction pathway. Exchange rate constant at glassy carbon electrode modified with Co(II) complexes was increased 2~10 times compared to bare electrode.

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Comparison of Quality of Red Pepper Powders Produced in Korea (한국산 고춧가루의 품질 비교)

  • Choi, Sun-Mi;Jeon, Young-Soo;Park, Kun-Young
    • Korean Journal of Food Science and Technology
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    • v.32 no.6
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    • pp.1251-1257
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    • 2000
  • Red pepper powder (Capsicum annuum L.) is one of the most important ingredients for making kimchi. Various aspects of the quality of the red pepper powders (RPP) produced in Korea depending on the varieties and producing districts were compared. The evaluated intrinsic elements were vitamin C, carotenoid, capsaicinoid and free sugar contents and the extrinsic element was ASTA (American Spice Trade Association) colors. The vitamin C content was the highest in Johong (230 mg%) RPP among the varieties and Youngyang (263 mg%) RPP among the producing districts. Myungpum RPP that contains high level of carotenoids showed increased level of ASTA color, it exhibited positive relationship between carotenoid contents and ASTA color. Capsaicinoid level in RPP was the highest in var. Chungyang (126.1 mg%) that was usually used soup and pungent cook. Free sugar contents which is related to sweetness were the highest in Youngyang RPP Youngyang RPP that preferentially used in the preparation of kimchi showed the highest levels in vitamin C, carotenoid, ASTA color, and free sugar contents, but the contents of capsaicinoid was the lowest.

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Natural isotopes and trace element analyses in glass samples (판유리 시료에서 동위원소 및 미량원소 분석법)

  • Min, Ji-Sook;Heo, Sangcheol;Kim, Jae-Guin;Kim, Eun-Ho;Kim, Dong-Wook;Chung, Hee-Sun
    • Analytical Science and Technology
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    • v.20 no.3
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    • pp.219-226
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    • 2007
  • Glass is frequently encountered as types of materials that are submitted to forensic science laboratories as a result of trace evidence transfers. The repeatability and the reproducibility of trace element analysis were presented. An analysis of variance (ANOVA) was performed on laser ablation inductively coupled plasma spectrometric analyses of the fragments to identify the source. Pairwise comparisons were completed for all samples. In a pairwise comparison, each sample was compared to each other for a possible [n(n-1)/2] (n : numbers of the samples) total comparison to associate/discriminate samples using Tukey's HSD method. The aim of this study was to determine the utility of LA-ICP-MS for multi-element analysis of forensic samples. The 12 glass fragments from two manufacturers were collected and analyzed to identify the source. An analysis of variance (ANOVA) was performed on 31 elements in NIST 612 Trace elements in Glass. Elements were classified into four categories defined by the combination of precision and variation of inter-samples. We selected 11 elements, 209Bi, 90Zr, 121Sb, 178Hf, 59Co, 238U, 208Pb, 140Ce, 118Sn, 49Ti and 137Ba. 6 pairs out of 66 possible pairs were not distinguished when compared by 137Ba (p<0.05). However, all samples were distinguished using both 49Ti and 137Ba (p<0.05). In conclusion, multi-elemental analysis with LA-ICP-MS is a potential tecnique for the discrimination of forensic samples.

Intravitreal Anti-vascular Endothelial Growth Factor Injections to Treat Neovascular Age-related Macular Degeneration: Long-term Treatment Outcomes (삼출 나이관련황반변성에 대한 항혈관내피성장인자 유리체내주사 치료의 장기 임상 결과)

  • Park, Yu Jeong;Son, Gi Sung;Kim, Yoon Jeon;Kim, June-Gone;Yoon, Young Hee;Lee, Joo Yong
    • Journal of The Korean Ophthalmological Society
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    • v.59 no.12
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    • pp.1142-1151
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    • 2018
  • Purpose: We assessed the visual and anatomical outcomes, and the safety profile of long-term intravitreal anti-vascular endothelial growth factor (VEGF) injections (aflibercept, ranibizumab, and bevacizumab) given to treat neovascular age-related macular degeneration (NAMD). Methods: We analyzed medical records collected over 7 years of treatment-naive NAMD patients who received outpatient clinic-based intravitreal anti-VEGF injections. All were treated employing either "treat-and-extend" or "as needed" protocols at the discretion of the retinal specialist. The number of injections, adverse events associated with injection, and measures of visual acuity (VA), central foveal thickness (CFT), and intraocular pressure (IOP) were recorded. Results: Overall, we assessed 196 eyes of 196 patients (average age $68.6{\pm}9.6years$; 77 females). Patients received an average of $17.3{\pm}13.5$ injections over $78.0{\pm}16.5months$ of clinical follow-up. The initial mean VA (logMAR) was $0.75{\pm}0.58$ and the CFT was $349.7{\pm}152.6{\mu}m$. Both parameters exhibited maximal improvements at the 6-month visit (p < 0.05). However, the clinical outcomes worsened over the 7-year clinical course; the best-corrected visual acuity (BCVA) was $0.91{\pm}0.78$ and the CFT was $284.5{\pm}105.8{\mu}m$ at 7 years. The BCVA at 7 years was significantly correlated with the initial BCVA. IOP-related events increased 11-fold and anterior chamber reactions increased 3-fold over the years, but no significant complications such as endophthalmitis were recorded. Conclusions: The use of intravitreal anti-VEGF agents was associated with initial visual improvements over 6 months but did not prevent the worsening of NAMD over 5 years. The BCVA at the initial visit was a strong predictor of the final BCVA. A more intensive injection schedule might improve long-term outcomes.