Synthesis, Electrical and Magnetic Properties of Fe304 Doped by Dy^3＋

The Dy^3＋ -doped Fe3O4 samples were synthesized by sol-gel method, and the effects of dopant on the electrical and magnetic properties were investigated. According to XRD analysis, the high concentration doping of dysprosium ions in Fe3O4 can not be obtained due to the difference of ionic radius, and Fe^3 ＋ ions are replaced by only a small amount of dysprosium ions. The magnetic property was characterized by VSM. The substitution results in the change of saturation magnetization, which may be due to the complex effects of increasing magnetization resulted from Dy^3＋ substitution and decreasing magnetization resulted from the impurity. The electrical property was characterized by four-probe method. With the increasing eoped content, magnetoresistance also increases, then decreases, and increases again. The spin-polarization of doped samples is lower than that of Fe3O4. Lower spin-polarization results in lower tunneling magnetoresistance. Fortunately, barrier was obtained by the second phase at the same time when sample was synthesized. The increase of appropriate barrier height leads to the change of tunneling magnetoresistance.     

减压精馏山苍子油提高柠檬醛含量的研究

研究探索了旨在提高柠檬醛含量的山苍籽油减压精馏的条件，取得了令人满意的结果。     

全球精油产量统计报告(一)

国际贸易中心(UNTAD/GATT)精油与油树脂分部曾于1974年和1986年发布了世界精油产量的统计数据,今年又发布了对全球范围的精油产量进行的统计。以下统计数据均以2007年全年的产量计算。     

百搭便捷小点心——原味美式麦芬

无论你是偏爱柠檬的清香．还是钟情蔓越莓的甘甜．无论你是喜欢蜜豆的软糯．亦或难舍巧克力丝滑．只需短短的30分钟．就能满足你挑剔的味蕾．一切皆源于本期的主角——原味美式麦芬。     

食品添加剂

乌克兰对中国的乳酸进行反倾销调查；美国延长对柠檬酸及柠檬酸盐双反案提交时间；欧盟对中国的味精作出的反倾销初裁；     

GdAlO3:Tb,RE中Tb,RE的能量传递研究

采用柠檬酸盐硝酸盐燃烧法制备了GdAlO3 Tb, RE荧光粉体.在紫外激发下(254nm),GdAlO3Tb发射绿色荧光(5D4→7F5,544nm),Dy共掺杂对绿色发光有增强作用,Ce共掺杂对GdalO3 Tb绿色发光有降低作用.激发谱和能谱研究表明Dy能级嵌入Tb主发射能级5D4(绿色发光能级)、5D3(蓝色发光能级)能级之间,Ce能级嵌入Tb主发射能级5D4、5D3能级上方.这种能级嵌入方式,使得稀土离子之间存在声子支持的共振能量传递,但T→Dy→Tb能量传递使Tb绿色发射(5D4→7FJ (J=3,4,5,6))增强,蓝色发射(5D3→7FJ (J=3,4,5,6))减弱;而Ce→Tb能量传递使Tb蓝色发射增强,绿色发射减弱.     

六种武器 独买不如众买——《合金装备4》全新周边

之前传出《合金装备4》要出PC版的信息，着实让柠檬欢喜了一阵子，后来却不幸地被证实是谣传，它依然由PS3独占（哭）！无可否认，于今年6月发售的它依然能延续前作的魅力，     

白柠檬精油提取加工技术研究

本试验确定了白柠檬精油提取方法为蒸馏法，研究了蒸馏法的最佳工艺参数，为工业化生产提供了科学依据。     

D-72磺酸树脂催化柠檬醛环化合成对伞花烃

以D-72磺酸树脂为催化剂,催化柠檬醛环化反应合成对伞花烃,考察了反应介质、柠檬醛的体积分数、催化剂用量、反应温度和反应时间对柠檬醛转化率和对伞花烃产率的影响。实验结果表明,以乙酸乙酯为介质,在柠檬醛体积分数为7.5%,催化剂用量为0.4 g,70℃下反应80 min,柠檬醛的转化率为100%,对伞花烃的产率为73.65%。