资兴柑橘皮总黄酮的微波辅助提取及其抗氧化活性研究

采用正交试验设计研究微波辅助提取资兴柑橘皮中总黄酮的工艺条件,并对资兴柑橘皮中总黄酮的抗氧化活性进行探讨。结果表明:资兴柑橘皮中总黄酮的最佳微波提取工艺为乙醇溶液体积分数70%、料液比1∶40(g/mL)、微波提取功率600W、提取温度70℃条件下提取20min,在此条件下,柑橘皮中总黄酮提取量可达21.11mg/g。影响柑橘皮中总黄酮提取效果的主次因素为:料液比>乙醇体积分数>提取温度>微波功率。柑橘皮总黄酮对清除自由基有明显的作用,且黄酮类化合物的添加量在实验范围内与其抗氧化性呈正相关,是一种潜在的具有抗氧化功能食品原料,该工艺技术适用于工业化大批量提取柑橘皮中总黄酮。     

稀土复合固体超强酸SO_4~(2-)/ZrO_2-CeO_2催化合成食用香料乳酸乙酯的研究

研究了以稀土复合固体超强酸SO_4~(2-)-/ZrO_2-CeO_2作催化剂,乳酸和乙醇为原料合成食用香料乳酸乙酯。通过正交实验考察了影响酯化反应的主要因素,确定的最佳合成条件为:乳酸用量为0.1 mol时,乙醇与乳酸物质的量之比为3.0:1,催化剂用量为乳酸质量的2.5%,回流反应3.0 h,带水剂环已烷20 mL/0.1 mol乳酸条件下,酯化率可达90.3%。且该催化剂具有良好的重复性和再生性。     

氮化硅粉体水基悬浮液电动特性的研究

通过测量氮化硅粉体在水溶液中的Zeta电位和颗粒大小，研究了不同条件下氮化硅水基悬浮液的电动特性。结果表明：氮化硅粉体的等电点在pH=4．2处，溶液的pH值以及引入的聚电解质均会使氮化硅颗粒表面的荷电状态发生变化，进而导致粉体在水溶液中的分散状况发生改变。在碱性条件下，添加适量的阴离子聚电解质NH4PAA有利于氮化硅水基悬浮液的稳定分散，而过量的NH4PAA会导致颗粒的重新团聚。     

Y-TZP/α-Al2O3复相陶瓷凝胶注模成型工艺的研究

本文研究了Y—TZP／α—Al2O3复相陶瓷的凝胶注模成型工艺,着重研究了低粘度高固相悬浮体的制备。利用自制分散剂PA对Y-TZP、α-Al2O3进行表面吸附改性,通过PA对两种颗粒的静电和空间稳定机制作用,在pH=9．5及最佳分散剂用量条件下制得低粘度高固相量的Y-TZP／α-Al2O3复相陶瓷悬浮体。     

对甲苯磺酸铜催化合成草酸二异戊酯

以对甲苯磺酸铜为催化剂,以草酸和异戊醇为原料合成草酸二异戊酯。通过正交实验考察了影响酯化反应的主要因素,确定的最佳合成条件为:草酸用量0.2 mol,n(异戊醇):n(草酸)=3.5;1,催化剂用量1.5 g,20 mL环己烷作带水剂,回流反应2.5 h,酯化率可达98.5%。该催化剂回收简单,重复使用7次后,酯化率仍然大于96%。     

Synthesis of rare earth sulfides and their UV-vis absorption spectra

Rare earth sulfides were systematically synthesized via the sulfurization of their commercial oxide powders using CS2 gas to shorten sulfurization time, and their UV-vis absorption spectra were investigated. The appropriate sulfurization conditions were studied. For the rare earth sulfides with the same crystal structure, the sulfurization temperature showed increasing tendency with the decrease of rare earth element atomic radii. The UV-vis absorption spectra of rare earth sulfides did not depend on the crystal structure of rare earth sulfides, but on the 4f electronic structure of rare earth element. The data showed that the optical band gaps of rare earth sulfides were irregular, and the values ranged from 1.65 to 3.75 eV.     

在无机及分析化学实验中进行素质教育的培养

无机及分析化学实验课是实施研究性教学，促进大学生培养研究性学习思维、提高科研素质的第一课堂。结合多年来对农科院校不同专业大学生的授课经验，从实验过程的三个阶段：前期、中期和后期，对每个阶段采用不同的教学侧重点，注重对学生的素质教育的培养。     

Preparation of ternary rare earth sulfide LaxCe2-xS3 as red pigment

In order to investigate the suitability of ternary rare earth sulfide LaxCe2-xS3 in plastic application as a red pigment,we prepared LaxCe2-xS3 via the sulfurization of the oxide powders using CS2 gas.In the sulfurization of LaxCe2-xS3,β-phase and γ-phase ternary rare earth sulfide LaxCe2-xS3 were synthesized at the sulfurization temperature of 1000 and 1250 oC for 3 h,respectively.The UV-vis absorption spectra of synthesized LaxCe2-xS3 showed that the absorption wavelengths of β-phase and γ-phase LaxCe2-xS3 samples were in the region of 617-670 nm and 607-653 nm,respectively.They were in red absorption region.Furthermore,the scanning electron microscopy(SEM)results of the synthesized LaxCe2-xS3 samples were investigated.The typical SEM micrographs indicated that the particle sizes of synthesized LaxCe2-xS3 were in the range of 0.5-6 μm.