Micro-encapsulated phase-change materials(micro PCMs) with Na_2 HPO_4·12 H_2 O encapsulated in poly(lactic acid)(PLA) shell were prepared by a solvent evaporation–precipitation method that involves the use of a ...Micro-encapsulated phase-change materials(micro PCMs) with Na_2 HPO_4·12 H_2 O encapsulated in poly(lactic acid)(PLA) shell were prepared by a solvent evaporation–precipitation method that involves the use of a coaxial needle. The effects of PLA concentration, stirring speed, injection rate of core and shell solutions, and polyvinyl alcohol(PVA) concentration on phase change properties were investigated. The thermal properties of microP CMs were characterized by differential scanning calorimetry(DSC). The capsules prepared under the optimal conditions are about 2 mm in diameter and show a latent heat of up to 122.2 J·g^(-1).展开更多
温室蓄热能力是影响温室内部环境的主要因素,相变材料蓄热能力强,正得到越来越广泛的应用。Na2HPO4·12H2O相变温度为35℃,十分适合应用于温室生产中,不过较大的过冷度使其应用受到限制。该文对Na2HPO4·12H2O过冷度的降低进行...温室蓄热能力是影响温室内部环境的主要因素,相变材料蓄热能力强,正得到越来越广泛的应用。Na2HPO4·12H2O相变温度为35℃,十分适合应用于温室生产中,不过较大的过冷度使其应用受到限制。该文对Na2HPO4·12H2O过冷度的降低进行了研究,通过熔解-冷却试验及步冷曲线的测定,研究不同成核剂对Na2HPO4·12H2O过冷度的降低效果。结果表明,在20 g Na2HPO4·12H2O中同时添加0.6 g Na2Si O3·9H2O和0.6 g石墨可将Na2HPO4·12H2O过冷度降为0℃;同时复合体系进行重复性试验效果良好,进行5次和10次循环后,过冷度仍为0℃,相变时间17 min左右,具有良好的稳定性。展开更多
A comparative study of Na2MoO4·2H2O and Na2HPO4·12H2O as inhibitors for magnetic refrigeration material La-Fe-Co-Si compound corrosion in distilled water at room temperature was carried out.Moreover,the inhi...A comparative study of Na2MoO4·2H2O and Na2HPO4·12H2O as inhibitors for magnetic refrigeration material La-Fe-Co-Si compound corrosion in distilled water at room temperature was carried out.Moreover,the inhibiting behavior of the mixture of Na2MoO4·2H2O and Na2HPO4·12H2O was investigated.Potentiodynamic polarization curves and electrochemical impedance spectroscopy （EIS） measurements were applied to study the corrosion behavior of the compound in the absence or presence of different concentrations of these inhibitors under the same experimental conditions.The study revealed that the mixture of 3.0×10–3 kg/L Na2MoO4·2H2O and 5.0×10–3 kg/L Na2HPO4·12H2O was the best inhibitor reaching the value of inhibition efficiency （ε%） up to 93.9%.Polarization curves showed that the studied compounds acted as anodic inhibitors.The potential of zero charge （PZC） of La-Fe-Co-Si compound was determined in distilled water in the absence of the studied inhibitors.Corrosion inhibition mechanisms for inhibitors were proposed in this work.展开更多
基金Supported by the National Natural Science Foundation of China(21476065)the China National Tobacco Corporation
文摘Micro-encapsulated phase-change materials(micro PCMs) with Na_2 HPO_4·12 H_2 O encapsulated in poly(lactic acid)(PLA) shell were prepared by a solvent evaporation–precipitation method that involves the use of a coaxial needle. The effects of PLA concentration, stirring speed, injection rate of core and shell solutions, and polyvinyl alcohol(PVA) concentration on phase change properties were investigated. The thermal properties of microP CMs were characterized by differential scanning calorimetry(DSC). The capsules prepared under the optimal conditions are about 2 mm in diameter and show a latent heat of up to 122.2 J·g^(-1).
文摘温室蓄热能力是影响温室内部环境的主要因素,相变材料蓄热能力强,正得到越来越广泛的应用。Na2HPO4·12H2O相变温度为35℃,十分适合应用于温室生产中,不过较大的过冷度使其应用受到限制。该文对Na2HPO4·12H2O过冷度的降低进行了研究,通过熔解-冷却试验及步冷曲线的测定,研究不同成核剂对Na2HPO4·12H2O过冷度的降低效果。结果表明,在20 g Na2HPO4·12H2O中同时添加0.6 g Na2Si O3·9H2O和0.6 g石墨可将Na2HPO4·12H2O过冷度降为0℃;同时复合体系进行重复性试验效果良好,进行5次和10次循环后,过冷度仍为0℃,相变时间17 min左右,具有良好的稳定性。
基金Project supported by the National High Technology Research and Development Program of China,the National Basic Research Program of China, and the National Natural Science Foundation of China (50971022, 50731007)
文摘A comparative study of Na2MoO4·2H2O and Na2HPO4·12H2O as inhibitors for magnetic refrigeration material La-Fe-Co-Si compound corrosion in distilled water at room temperature was carried out.Moreover,the inhibiting behavior of the mixture of Na2MoO4·2H2O and Na2HPO4·12H2O was investigated.Potentiodynamic polarization curves and electrochemical impedance spectroscopy （EIS） measurements were applied to study the corrosion behavior of the compound in the absence or presence of different concentrations of these inhibitors under the same experimental conditions.The study revealed that the mixture of 3.0×10–3 kg/L Na2MoO4·2H2O and 5.0×10–3 kg/L Na2HPO4·12H2O was the best inhibitor reaching the value of inhibition efficiency （ε%） up to 93.9%.Polarization curves showed that the studied compounds acted as anodic inhibitors.The potential of zero charge （PZC） of La-Fe-Co-Si compound was determined in distilled water in the absence of the studied inhibitors.Corrosion inhibition mechanisms for inhibitors were proposed in this work.
