• 제목/요약/키워드: Capacity retention

검색결과 512건 처리시간 0.021초

Genotypic and Environmental Effects on Cookie Quality of Korean Winter Wheat

  • Hong, Byung-Hee;Park, Chul-Soo;Baik, Byung-Kee
    • 한국작물학회지
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    • 제46권5호
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    • pp.352-359
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    • 2001
  • Cookie baking properties and relationships between cookie baking properties and flour characteristics were evaluated for two years, 1997 and 1998, and at two locations, Suwon and Deokso, with Korean winter wheat cultivars and lines. Cookie baking parameters, except for cookie diameter and top grain score, were influenced by locations and years. Chokwang, Suwon 274, Suwon 275, Suwon 277 and Urimil showed larger cookie diameter and excellent top grain score compared to the other Korean winter wheat cultivars and lines. Among the flour characteristics, protein content, damaged starch content, alkaline water retention capacity and flour swelling volume showed high positive correlation coefficients with cookie baking parameters. Friabilin-present lines showed larger cookie diameter, suitable surface structure of cookie and softer snapping force than the friabilin-absent lines.

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비이온계 계면활성제 수용액이 PET직물의 습윤특성에 미치는 영향 제1보 : Span 20과 Tween 20의 혼합계와 희석계 (Effect of Nonionic Surfactant Solutions on Wetting and Absorbancy of PET Fabric 1. Mixtures and Dilutions of Span 20 and Tween 20)

  • 김천희
    • 한국의류학회지
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    • 제27권9_10호
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    • pp.1153-1159
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    • 2003
  • The effects of changing aqueous solution properties by nonionic surfactants on wetting behavior and water retention properies of hydrophobic PET (polyethylene terephthalate) fabric were reported. The aqueous solution properties were diversified by mixing and diluting two nonionic surfactants, i.e., sorbitan monolaurate (Span 20) and polyoxyethylene(20) sorbitan monolaurate (Tween 20). The surface wetting properties ($cos{\theta}$) of PET fabric were greatly improved by adding $10^{-1}g/dl$ Tween 20 and further improved by mixing Span 20 to the system. The water retention properties (W) of PET fabric were also greatly increased by addition of $10^{-1}g/dl$ Tween 20. In diluted surfactant systems, the $cos{\theta}'s$ were increased with decreasing surface tension of aqueous liquids. The ratios of aqueous liquid retained in the pore structure to liquid retention capacity (W/H) were also increased with decreasing surface tension, however, W/H values were dramatically increased right after critical micelle concentration (cmc). The existence of micelles was important for the retention of aqueous liquids in the fabric. The critical surface tension of PET fabric used was found to be 28.7dyne/cm.

Effects of Phosphorous-doping on Electrochemical Performance and Surface Chemistry of Soft Carbon Electrodes

  • Kim, Min-Jeong;Yeon, Jin-Tak;Hong, Kijoo;Lee, Sang-Ick;Choi, Nam-Soon;Kim, Sung-Soo
    • Bulletin of the Korean Chemical Society
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    • 제34권7호
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    • pp.2029-2035
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    • 2013
  • The impact of phosphorous (P)-doping on the electrochemical performance and surface chemistry of soft carbon is investigated by means of galvanostatic cycling and ex situ X-ray photoelectron spectroscopy (XPS). P-doping plays an important role in storing more Li ions and discernibly improves reversible capacity. However, the discharge capacity retention of P-doped soft carbon electrodes deteriorated at $60^{\circ}C$ compared to non-doped soft carbon. This poor capacity retention could be improved by vinylene carbonate (VC) participating in forming a protective interfacial chemistry on soft carbon. In addition, the effect of P-doping on exothermic thermal reactions of lithiated soft carbon with electrolyte solution is discussed on the basis of differential scanning calorimetry (DSC) results.

Van der Waals Volume을 이용한 역상 컬럼에서의 유기화합물들의 용출거동 (Retention Behavior of Organic Compounds on Reversed-Phase Column expected by Van der Waals Volume)

  • 박운규;이용문;문동철;강종성
    • 분석과학
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    • 제6권4호
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    • pp.383-390
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    • 1993
  • 지방족 카르복실산류, 방향족화합물류 및 알킬벤젠류에 대하여 역상 HPLC에서의 용출예측 방법을 검토하였다. 용출 파라미터로서 분자 크기를 나타내는 Van der Waasls 부피와 log k'와의 상관성을 검토한 결과, 양호한 직선성을 얻을 수 있었다. 용리액의 조성을 변화시키면서 또는 분리컬럼 온도를 변화시키면서 지방족 카르복실산류, 방향족화합물류 및 알킬벤젠류에 대하여 검토한 결과, acetonitrile이 log k'와 Van der Waals 부피와의 상관성이 가장 좋았다. 본 방법을 이용하여 역상 HPLC system에서 Van der Waasls 부피가 40~250 사이의 유기화합물들의 용출을 예측할 수 있었다. 각 용매의 용출력 세기는 methanol

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친환경 도로포장용 투수콘크리트의 제조와 이를 이용한 도로포장시스템의 수질정화특성 (Development of Environmentally Favorable Porous Concrete and Water Purification Characteristics by the Pavement System)

  • 홍종현;김문훈;양철신
    • 한국환경과학회지
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    • 제15권11호
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    • pp.1045-1052
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    • 2006
  • Stormwater pollution is a major problem in urban areas. Pollutants like heavy metals and harmful chemicals in the runoff can endanger soil and ground water, when they are not sufficiently removed doting infiltration. Strength and infiltration capacity of porous concrete are the major problems that must be considered if permeable pavement system are demanded to be used in a drive way application. In this study, a series of compacted porous concrete mixtures and the system of pavement ate tested for the physical characteristics like compressive strength, flexural strength, unit weight, porosity, water permeability, and the purification capacity of contaminated water. The test results obtained indicate that the strength and infiltration capacity of porous concrete are strongly related to its matrix proportion and compaction energy and providing adequate filter layers underneath pavement surface course is one of the most important design considerations of permeable pavement system for pollution retention purpose.

전고상박막전지를 위한 (Li,La)TiO3 고체전해질의 제조와 특성 (Lithium Lanthanum Titanate Solid Electrolyte for All-Solid-State Lithium Microbattery)

  • 안준구;윤순길
    • 한국전기전자재료학회논문지
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    • 제17권9호
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    • pp.930-935
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    • 2004
  • $({Li}_{0.5}0{La}_{0.5}){TiO}_3$ (LLTO) solid electrolyte was grown on LiCo{O}_2 (LCO) cathode films deposited on $Pt/Ti{O}-2/Si{O}_2/Si$ substrate using pulsed laser deposition for all-solid-state lithium microbattery. LLTO solid electrolyte exhibits an amorphous phase at various deposition temperatures. LLTO films deposited at 10$0^{\circ}C$ showed a clear interrace without any chemical reaction with LCO, and showed an initial discharge capacity of 50 $\mu$Ah/cm$^2$-$\mu$m and capacity retention of 90 % after 100 cycles with Li anode in 1mol$ LiCl{O}_4$ in propylene carbonate (PC). The increase of capacity retention in LLTO/LCO structure than LCO itself was attributed to the structural stability of LCO cathode films by the stacked LLTO. The cells of LLTO/LCO with LLTO grown at $100^{\circ}C$ showed a good cyclic property of 63.6 % after 300 cycles. An amorphous LLTO solid electrolyte is possible for application to solid electrolyte for all-solid-state lithium microbattery.

Enhancement of Electrochemical Activity of Ni-rich LiNi0.8Mn0.1Co0.1O2 by Precisely Controlled Al2O3 Nanocoatings via Atomic Layer Deposition

  • Ramasamy, Hari Vignesh;Sinha, Soumyadeep;Park, Jooyeon;Gong, Minkyung;Aravindan, Vanchiappan;Heo, Jaeyeong;Lee, Yun-Sung
    • Journal of Electrochemical Science and Technology
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    • 제10권2호
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    • pp.196-205
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    • 2019
  • Ni-rich layered oxides $Li(Ni_xCo_yMn_z)O_2$ (x + y + z = 1) have been extensively studied in recent times owing to their high capacity and low cost and can possibly replace $LiCoO_2$ in the near future. However, these layered oxides suffer from problems related to the capacity fading, thermal stability, and safety at high voltages. In this study, we use surface coating as a strategy to improve the thermal stability at higher voltages. The uniform and conformal $Al_2O_3$ coating on prefabricated electrodes using atomic layer deposition significantly prevented surface degradation over prolonged cycling. Initial capacity of 190, 199, 188 and $166mAh\;g^{-1}$ is obtained for pristine, 2, 5 and 10 cycles of ALD coated samples at 0.2C and maintains 145, 158, 151 and $130mAh\;g^{-1}$ for high current rate of 2C in room temperature. The two-cycle $Al_2O_3$ modified cathode retained 75% of its capacity after 500 cycles at 5C with 0.05% capacity decay per cycle, compared with 46.5% retention for a pristine electrode, at an elevated temperature. Despite the insulating nature of the $Al_2O_3$ coating, a thin layer is sufficient to improve the capacity retention at a high temperature. The $Al_2O_3$ coating can prevent the detrimental surface reactions at a high temperature. Thus, the morphology of the active material is well-maintained even after extensive cycling, whereas the bare electrode undergoes severe degradation.

리튬이차전지용 고용량 음극을 위한 구리@코발트산화물 코어-쉘 수지상 기반 3차원 다공성 박막 (Three-dimensional porous films consisting of copper@cobalt oxide core-shell dendrites for high-capacity lithium secondary batteries)

  • 주소영;최윤주;최우성;신헌철
    • 한국표면공학회지
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    • 제56권1호
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    • pp.104-114
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    • 2023
  • Three dimensional (3D) porous structures consisting of Cu@CoO core-shell-type nano-dendrites were synthesized and tested as the anode materials in lithium secondary batteries. For this purpose, first, the 3D porous films comprising Cu@Co core-shell-type nano-dendrites with various thicknesses were fabricated through the electrochemical co-deposition of Cu and Co. Then the Co shells were selectively anodized to form Co hydroxides, which was finally dehydrated to get Cu@CoO nanodendrites. The resulting electrodes exhibited very high reversible specific capacity almost 1.4~2.4 times the theoretical capacity of commercial graphite, and excellent capacity retention (~90%@50th cycle) as compared with those of the existing transition metal oxides. From the analysis of the cumulative irreversible capacity and morphology change during charge/discharge cycling, it proved that the excellent capacity retention was attributed to the unique structural feature of our core-shell structure where only the thin CoO shell participates in the lithium storage. In addition, our electrodes showed a superb rate performance (70.5%@10.8 C-rate), most likely due to the open porous structure of 3D films, large surface area thanks to the dendritic structure, and fast electron transport through Cu core network.

생물막을 이용한 다공성 콘크리트의 수질정화 효율 개선에 대한 연구 (Research on improvement of water purification efficiency by porous concrete using bio-film)

  • 김태훈;;안태웅;최이송;오종민
    • 환경영향평가
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    • 제20권6호
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    • pp.815-821
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    • 2011
  • This study aims to estimate the biological decomposition capacity of MPC(Microorganism Porous-Concrete). MPC has specific surface area formed by inside pores, and bio compound was added to those pores to reduce pollutants loading. To evaluate the water purification capacity of MPC, we carried out the comparative studies using different media types [GPC(General Porous-concrete), CPC(Compound porous-concrete), LPC(Lightweight aggregate porous-concrete)] under the condition of CFSTR, and different retention times (30, 60 and 120 min). We also estimated the purification capacity of MPC under different concentrations of pollutant loadings. The MPC showed higher efficiency in water purification function than other conventional porous concretes with efficient decrease rates of SS, BOD, COD, and nutrient concentrations. In the comparison experiment for different retention times, MPC showed the highest removal efficiency for all tested pollutants in the longest retention time(120 min). In the long period test, the removal efficiencies of MPC concrete were high until 100 days after the set up of the operation, but began to decrease. Outflow flux was invariable compared with inflow flux so that extra detention time for media fouling such as back washing is not needed. But the results suggested that appropriate management is necessary for long-term operation of MPC. As the final outcome, MPC using bio organisms is considered to be efficient for stream water purification when they used as substrates for artificial river structure.