1,844 research outputs found

    Characterization of thermally aged AlPO4-coated LiCoO2 thin films

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    The electrochemical properties and stability during storage of pristine and AlPO4-coated LiCoO2 thin films were characterized. The wide and smooth surface of the thin film electrode might provide an opportunity for one to observe surface reactions with an electrolyte. The rate capability and cyclic performance of the LiCoO2 thin film were enhanced by AlPO4 surface coating. Based on secondary ion mass spectrometry analysis and scanning electron microscopy images of the surface, it was confirmed that the coating layer was successfully protected from the reactive electrolyte during storage at 90°C. In contrast, the surface of the pristine sample was severely damaged after storage

    Catalytic properties of Co3O4 nanoparticles for rechargeable Li/air batteries

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    Three types of Co3O4 nanoparticles are synthesized and characterized as a catalyst for the air electrode of a Li/air battery. The shape and size of the nanoparticles are observed using scanning electron microscopy and transmission electron microscopy analyses. The formation of the Co3O4 phase is confirmed by X-ray diffraction. The electrochemical property of the air electrodes containing Co3O4 nanoparticles is significantly associated with the shape and size of the nanoparticles. It appears that the capacity of electrodes containing villiform-type Co3O4 nanoparticles is superior to that of electrodes containing cube- and flower-type Co3O4 nanoparticles. This is probably due to the sufficient pore spaces of the villiform-type Co3O4 nanoparticles

    DETERMINATION OF THE 129I IN PRIMARY COOLANT OF PWR

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    Among the radioactive wastes generated from the nuclear power plant, a radioactive nuclide such as 129I is classified as a difficult-to-measure (DTM) nuclide, owing to its low specific activity. Therefore, the establishment of an analytical procedure, including a chemical separation for 129I as a representative DTM, becomes essential.In this report, the adsorption and recovery rate were measured by adding 125I as a radio-isotopic tracer (t1/2 = 60.14 d) to the simulation sample, in order to measure the activity concentration of 129I in a pressurized-water reactor primary coolant. The optimum condition for the maximum recovery yield of iodine on the anion exchange resins (AG1 x2, 50-100 mesh, Cl− form) was found to be at pH 7.In this report, the effect of the boron content in a pressurized-water reactor primary coolant on the separation process of 129I was examined, as was the effect of 3H on the measurement of the activity of iodine. As a result, no influence of the boron content and of the simultaneous 3H presence was found with activity concentrations of 3H lower than 50 Bq/mL, and with a boron concentration of less than 2,000 μg/mL

    Enhanced electrochemical properties of fluoride-coated LiCoO2 thin films

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    The electrochemical properties of fluoride-coated lithium cobalt oxide [LiCoO2] thin films were characterized. Aluminum fluoride [AlF3] and lanthanum fluoride [LaF3] coating layers were fabricated on a pristine LiCoO2 thin film by using a spin-coating process. The AlF3- and LaF3-coated films exhibited a higher rate capability, cyclic performance, and stability at high temperature than the pristine film. This indicates that the AlF3 and LaF3 layers effectively protected the surface of the pristine LiCoO2 film from the reactive electrolyte

    Effects of Temperature on Development and Voltinism of Chaetodactylus krombeini (Acari: Chaetodactylidae): Implications for Climate Change Impacts

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    Temperature plays an important role in the growth and development of arthropods, and thus the current trend of climate change will alter their biology and species distribution. We used Chaetodactylus krombeini (Acari: Chaetodactylidae), a cleptoparasitic mite associated with Osmia bees (Hymenoptera: Megachilidae), as a model organism to investigate how temperature affects the development and voltinism of C. krombeini in the eastern United States. The effects of temperature on the stage-specific development of C. krombeini were determined at seven constant temperatures (16.1, 20.2, 24.1, 27.5, 30.0, 32.4 and 37.8°C). Parameters for stage-specific development, such as threshold temperatures and thermal constant, were determined by using empirical models. Results of this study showed that C. krombeini eggs developed successfully to adult at all temperatures tested except 37.8°C. The nonlinear and linear empirical models were applied to describe quantitatively the relationship between temperature and development of each C. krombeini stage. The nonlinear Lactin model estimated optimal temperatures as 31.4, 32.9, 32.6 and 32.5°C for egg, larva, nymph, and egg to adult, respectively. In the linear model, the lower threshold temperatures were estimated to be 9.9, 14.7, 13.0 and 12.4°C for egg, larva, nymph, and egg to adult, respectively. The thermal constant for each stage completion were 61.5, 28.1, 64.8 and 171.1 degree days for egg, larva, nymph, and egg to adult, respectively. Under the future climate scenarios, the number of generations (i.e., voltinism) would increase more likely by 1.5 to 2.0 times by the year of 2100 according to simulation. The findings herein firstly provided comprehensive data on thermal development of C. krombeini and implications for the management of C. krombeini populations under global warming were discussed

    Regulation of Apoptosis during Environmental Skin Tumor Initiation

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    Skin cancer is more prevalent than any other cancer in the United States. Nonmelanoma skin cancers are the more common forms of skin cancer that affect individuals. The development of squamous cell carcinoma, the second most common type of skin cancer, can be stimulated by exposure of environmental carcinogens, such as chemical toxicants or UVB. It is developed by three distinct stages: initiation, promotion, and progression. During the initiation, the fate of DNA-damaged skin cells is determined by the homeostatic regulation of pro-apoptotic and antiapoptotic signaling pathways. The imbalance or disruption of either signaling will lead to the survival of initiated cells, resulting in the development of skin cancer. In this chapter, we will discuss signaling pathways that regulate apoptosis and the impact of their dysfunction during skin tumor initiation

    Regulation of Apoptosis during Environmental Skin Tumor Initiation

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    Skin cancer is more prevalent than any other cancer in the United States. Nonmelanoma skin cancers are the more common forms of skin cancer that affect individuals. The development of squamous cell carcinoma, the second most common type of skin cancer, can be stimulated by exposure of environmental carcinogens, such as chemical toxicants or UVB. It is developed by three distinct stages: initiation, promotion, and progression. During the initiation, the fate of DNA-damaged skin cells is determined by the homeostatic regulation of pro-apoptotic and antiapoptotic signaling pathways. The imbalance or disruption of either signaling will lead to the survival of initiated cells, resulting in the development of skin cancer. In this chapter, we will discuss signaling pathways that regulate apoptosis and the impact of their dysfunction during skin tumor initiation

    Aspiration and outflow of the intermediate water in the East/Japan Sea through the Tsugaru Strait

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    Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 35 (2008): L07601, doi:10.1029/2007GL032981.Outflow of the intermediate water in the East/Japan Sea through the Tsugaru Strait is inferred from the fact that profiling floats deployed below the sill depth in the central East/Japan Sea moved out to the Northwest Pacific Ocean through the Strait. Careful analysis of the float trajectories reveals that profiling floats parked at 350m, 700m, and 800m could be uplifted from depths below the sill of the Tsugaru Strait and moved over the 140m deep sill with a probability close to 100%. Application of an analytical model for the Bernoulli suction shows that intermediate waters can be aspirated over the sill depth of the Tsugaru Strait in late winter.This study was partly supported by the project of ARGO for Data Assimilation project in the Meteorological Research Institute/KMA, the Korea EAST-1(East Asian Seas Time series East Sea) Program from the Ministry of Maritime Affairs and Fisheries, and Korea Research Foundation Grant (KRF-2005-070-C00142). The first author was partly supported by the Ministry of Education, Korea, through the BK21 project
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