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Low-temperature combustion synthesis of CuCr2O4 spinel powder for spectrally selective paints 总被引:1,自引:0,他引:1
Geng Qingfen Zhao Xin Gao Xianghu Yang Shengrong Liu Gang 《Journal of Sol-Gel Science and Technology》2012,61(1):281-288
CuCr2O4 spinel powder with high quality black hue, investigated as solar-absorbing pigment for spectrally selective paint, was synthesized
by an environmental friendly sol–gel combustion process using citric acid as the fuel and metal nitrates as oxidizers. Single-phase
CuCr2O4 spinel crystals were obtained after heat treatment of the as-burnt powder at a low temperature (600 °C) and the average crystallite
size of the CuCr2O4 powders increased with the calcining temperature. Morphological analysis of powders calcined at various temperatures was
done by field emission scanning electron microscopy. CuCr2O4 powder calcined at 700 °C was chosen as pigment to fabricate thickness sensitive spectrally selective paint coatings by simple
spray-coating technique. For the sake of comparison, the as-burnt powder composed of mixed metal oxides (i.e., CuO and Cr2O3) was also used as pigment. The results reveal that the spinel CuCr2O4 based paint coatings exhibit much higher spectral selectivity (α
s = 0.88–0.91, ε
100 = 0.27–0.35) which is depending on the coating thicknesses than that of coatings using as-burnt powder as pigment (α
s = 0.83–0.88, ε
100 = 0.60–0.66). The CuCr2O4-based paint coatings showed no visible degradation after 600 h of condensation test and the performance criterion value is
0.04, indicating that the coatings have excellent long term stability. 相似文献
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A novel and efficient method for the synthesis of gem-difluoroallylboronates via copper-catalyzed defluorinative borylation of α-trifluoromethyl alkenes with B2pin2 using Xantphos as ligand and NaOtBu as base was developed. 相似文献
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自制恒压恒流电源在物理实验中的应用 总被引:1,自引:0,他引:1
研制了一种物理实验专用的励磁电流恒流电源,对恒流电源的电流输出稳定性进行了测试,并以恒流电源在霍尔元件测磁场实验中的应用为例,进行了普通稳压电源和恒流电源两种电源的实验数据对比测试.测试结果表明,电流输出稳定度可达到0.1%,恒流电源所测数据的线性化程度高于普通稳压电源所测数据. 相似文献
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本文采用脉冲激光沉积(PLD)技术在p型4H-SiC衬底上,制备出沿(403)择优生长的β-Ga2O3薄膜。结果表明,衬底生长温度对β-Ga2O3薄膜的形貌、结构、组分,以及生长机理都有重要影响。当生长温度由300 ℃升高至500 ℃时,薄膜结晶质量随生长温度升高而提高,当温度进一步升高到600 ℃时,薄膜结晶质量变差,这是由于在相对低温(500 ℃以下)阶段,生长温度越高,沉积在衬底上原子的动能越大,越容易迁移,使得β-Ga2O3薄膜主要按照二维生长模式进行生长,薄膜结晶质量提高,表现为随着生长温度升高,粗糙度降低。但当温度上升到600 ℃时,由于4H-SiC衬底和β-Ga2O3薄膜之间的热膨胀系数存在差异,导致薄膜生长由主要以二维生长模式向三维岛状演变。基于p-4H-SiC/n-β-Ga2O3构筑的异质结太阳电池,其标准测试条件下光电转换效率达到3.43%。 相似文献
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Let ■ be a k-uniform hypergraph on n vertices with degree sequence △= d1≥…≥ dn =δ. In this paper, in terms of degree di , we give some upper bounds for the Z-spectral radius of the signless Laplacian tensor (Q(■)) of ■. Some examples are given to show the efficiency of these bounds. 相似文献
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采用低硒饲料饲养大鼠造成体内贫硒。14周时测定血浆中脂质过氧化物(LPO)、前列环素(PGI2)和血栓素(TXA2)的水平以及部分血液流变学指标。实验第39周,测定血管组织一氧化氮合酶(NOS)活性及一氧化氮(NO)水平。结果显示,低硒饲料组的血管NOS活性、NO水平显著低于常规饲料的对照组;而在实验第14周时,当低硒饲料组的血硒、血谷胱甘肽过氧化物酶(GSH-Px)活性显著下降、血浆LPO水平明显上升的同时,其对应的血浆6-酮-PGF1α水平也显著降低,但其TXB2与对照组无显著差异。此外,随着大鼠体内的贫硒,其红细胞变形能力下降,但红细胞聚集指数和血沉方程K值提高。因此,硒不足可能会通过影响NOS活性和PGI2的合成以及红细胞特性而损害微循环功能。 相似文献
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本文介绍了一种电位差计专用高稳定性电源,其具有稳定性好.可靠耐用,有两组输出,体积小巧,使用方便等特点。 相似文献