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维生素C是人体所必需的营养物质之一,其含量是评定果实营养价值的重要参数之一。文章采用直接碘量法测定了黄瓜中维生素C的含量。结果表明黄瓜中Vit C的含量为0.08174 mg/g,加标回收率为98.52%~98.80%。说明黄瓜中Vit C含量较高,具有较大的营养价值。 相似文献
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摘要:以绿茶为原料,水为浸提溶剂,采用离子沉淀法对茶叶中茶多酚的提取进行了研究。探讨了沉淀剂种类、沉淀剂用量、溶剂用量、浸提温度、浸提时间5个因素对茶叶中茶多酚提取的影响,优化了茶多酚提取的最佳工艺条件。结果表明,当以AlCl3为沉淀剂且m沉淀剂:m茶叶=1:5、溶剂用量m茶叶:m水=1:20、浸提温度为水浴75℃、浸提时间45min时,茶多酚的提取率最高,为14.12%。 相似文献
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Luminescent material Ba3Gd(BO3)3 doped with Eu3+ ion was prepared by high temperature solid-state method. The preparing conditions, luminescent properties, and particle morphology of Ba3Gd(BO3)3:Eu3 + phosphor were studied with X-ray diffraction (XRD), fluorescence spectroscopy, and scanning electron microscopy (SEM). The results obtained by XRD showed that pure phase of Ba3Gd(BO3)3 was obtained at 1000℃. Images from SEM displayed that the particles of Ba3Gd(BO3)3:Eu3+ phosphor had a spherical shape with an average diameter of about 200-400 nm. The luminescence spectra showed that Ba3Gd(BO3)3:Eu3+ phosphor was effectively excited by the near ultraviolet (UV) light (396 nm) and blue light (466 nm). The main emission peaks of Ba3Gd(BO3)3:Eu3+ phosphor were assigned to the supersensitive transition 5D0-7F2 (611 and 616 nm) of Eu3+ ion when samples were excited at 255 and 396 nm, respectively, and the luminescent intensity of Ba3Gd(BO3)3:Eu3+ at 611 and 616 nm reached to the maximum when the doped content of Eu3+ ion was 10mol.%. Therefore, this phosphor could be a promising red component for possible applications in the field of white LED. 相似文献
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