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
Using THF and water as solvent, piperazine as a template, a novel two dimensional layered zinc phosphate 1.5[Zn2(PO4)(HPO4)2]·H2O has been prepared solvothermally, and its structure is determined at 293K by Sieme...Using THF and water as solvent, piperazine as a template, a novel two dimensional layered zinc phosphate 1.5[Zn2(PO4)(HPO4)2]·H2O has been prepared solvothermally, and its structure is determined at 293K by Siemens Smart 1000 CCD diffractometer monoclinic, P21/c, a=0.81244(3)nm, b=2.61706(12)nm, c=0.83775(3)nm, β=110.981(2)°, V=1.66313(11)nm3, Z=4, R=0.0285, wR=0.0719. The structure con sists of vertex sharing ZnO4, HPO4, and PO4 tetrahedra, and double protonated organic cations, which results in formation of undulating 4 ring chains and 12 ring sheets. A network of hydrogen bonds involving both layer to layer and layer to amine interaction holds the phosphate layer together. CCDC: 200374.展开更多
建立了一种用离子色谱法同时测定Na_3PO_4·12H_2O中的Cl^-和SO_4^(2-)的分析方法。该方法采用分离时间20min,分离度为3.02的Metrosep A Supp 4 250/4.0型色谱柱,柱温为35℃,流速为0.8mL/min。两种离子的标准曲线的相关系数达到了0....建立了一种用离子色谱法同时测定Na_3PO_4·12H_2O中的Cl^-和SO_4^(2-)的分析方法。该方法采用分离时间20min,分离度为3.02的Metrosep A Supp 4 250/4.0型色谱柱,柱温为35℃,流速为0.8mL/min。两种离子的标准曲线的相关系数达到了0.9999。Cl^-和SO_4^(2-)的稀释液的测定结果的相对标准偏差分别为1.02%,2.26%;检出限分别为0.010mg/L,0.011mg/L;加标回收率分别96.0%,94.0%。与HG/T 2517-2009中Cl^-和SO_4^(2-)的测定方法相比,该方法的相对误差仅为分别为2.78%和0.00%。因此,该方法具有较高的精密度和准确度,且分析时间短,方法简单,可作为缓蚀阻垢剂Na_3PO_4·12H_2O中的Cl^-和SO_4^(2-)含量分析的常规方法。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
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Using THF and water as solvent, piperazine as a template, a novel two dimensional layered zinc phosphate 1.5[Zn2(PO4)(HPO4)2]·H2O has been prepared solvothermally, and its structure is determined at 293K by Siemens Smart 1000 CCD diffractometer monoclinic, P21/c, a=0.81244(3)nm, b=2.61706(12)nm, c=0.83775(3)nm, β=110.981(2)°, V=1.66313(11)nm3, Z=4, R=0.0285, wR=0.0719. The structure con sists of vertex sharing ZnO4, HPO4, and PO4 tetrahedra, and double protonated organic cations, which results in formation of undulating 4 ring chains and 12 ring sheets. A network of hydrogen bonds involving both layer to layer and layer to amine interaction holds the phosphate layer together. CCDC: 200374.
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。
