ZnO薄膜的丙酮气敏特性研究

用直流磁控反应溅射法,分别在Si(111)基片及Al2O3陶瓷基片上制备了ZnO薄膜,并进行TiO2、SnO2、Al2O3或CuO的掺杂和退火处理。用XRD分析了退火前后晶型的变化,利用气敏测试系统对各样品进行了气敏特性测试。结果表明:经过700℃退火后的样品,在最佳工作温度为220℃时,对丙酮有很好的选择性和很高的灵敏度(34.794)。掺杂TiO2或SnO2,可提高ZnO薄膜传感器对丙酮的灵敏度(57.963)。     

基于拉曼光谱的微结构光纤丙酮传感检测研究

结合拉曼光谱特异性和微结构光纤所需样品体积 小(纳升量级)等优点,基于拉曼光谱法,利用三孔MOF作为传 感头,搭建了丙酮浓度传感系统。 丙酮溶液在毛细管吸附作用下进入到MOF的空气孔内, 在倏逝波激发下丙酮溶液产生拉曼信号,通过探测耦合回微结构光纤纤芯的拉曼 信号强度探测丙酮浓度。实验利用丙酮C-H键(2843cm－1)伸缩振动峰作为其特 征谱线,同时以水的H-O键(3371cm－1 )伸缩振动峰作为内标物组成相对强度,对 溶液中的丙酮含量进行测定。实验结果表明,当丙酮浓度从5%增加到50%时,丙 酮浓度与丙酮C-H键伸缩振动峰和水H-O键伸缩振动峰强度比值呈线性关系,二 者相关系数为0.98。本文系统也可以用于其它挥发性有机化合物的定 性和定量分析。     

花状ZnO纳米棒的合成及丙酮敏感特性的研究

利用水热法合成花状的ZnO纳米棒,并对其进行X射线衍射（X-ray diffraction, XRD)与扫描电子显微镜（scanning electron microscope, SEM) 表征.以该ZnO为敏感材料制成了旁热式结构气体传感器,测试了样品在不同温度下对丙酮气体的灵敏度.结果表明样品在290℃下对于丙酮气体具有高的灵敏度、快的响应恢复速度等特点.测试了传感器对于常见干扰气体的灵敏度,表明器件具有良好的选择性.     

高效液相色谱法测定棉籽仁中棉酚的含量

目的：建立棉籽仁中棉酚含量的高效液相色谱测定方法。方法：采用ODS-C18 色谱柱(4.6mm × 200mm,5μm),柱温25℃,流动相为甲醇- 体积分数1% 磷酸溶液(85:15,V/V),流速1.0mL/min,检测波长235nm。结果：棉酚质量浓度在1.9～34.9μg/mL 范围内线性关系良好;棉酚的加标回收率为97.8%～100.3%,RSD值为0.4%～1.2%。结论：此法操作简便、快速、灵敏、准确,样品处理简便易行,适于测定棉籽仁中棉酚的含量。     

丙酮制浆对竹纤维长度的影响

以竹材为原料，探讨了在不同浓度有机溶剂、盐酸和催化剂等条件下，丙酮制浆对纤维长度的影响。丙酮制浆对纤维长度具有显著的影响，随着丙酮及酸浓度的增加，纤维长度减小；而随催化剂量的增加，纤维长度增长。在丙酮20％，盐酸浓度2％及催化剂浓度50g／L条件下，分离纤维的长度变化较小，且木素得率较高，分离效果较好。     

Use of Palm Mid-Fraction in White Chocolate Formulation

Samples of two types of palm mid-fraction (PMF I, a commercial sample and PMF II, from a laboratory-scale acetone fractionation of PMF I) and a Malaysian deodorised cocoa butter sample were used as the main components in the fat phase for white chocolate formulation. The monounsaturatedtriacylglycerol contents of these fats were 853, 899 and 903 g kg⁻¹, respectively.All the fats had free fatty acid contents of less than 10 g kg⁻¹ and melting points in the range of 34·0–34·5°C. The solid fat content profiles for the three fats were very steep. Differential scanning calorimeter analyses showed that all the fats had two melting peaks, T1 and T2. Results of the study showed that the tempering time to produce a well-tempered chocolate using PMF I was longer than that using PMF II, whereas, the time to produce a well-tempered cocoa butter chocolate increased with increase in the tempering temperature. Chocolates made with PMF I and II were well tempered between 17 and 19°C and with cocoa butter at 23°C. Thermal analyses, carried out on the chocolate showed that PMF I and II produced three melting peaks, T1, T2′ and T2 whereas most of the cocoa butter chocolates exhibited only one melting peak, T2. Storage studies showed that most of the chocolates had good bloom resistance for up to 12 weeks storage.     

添加有机前体物质对发酵生产HA的影响研究

研究了摇瓶发酵过程中添加物对兽疫链球菌Streptococcus zooepidemicus发酵生产透明质酸的影响。结果表明：在发酵5h时,装液量80mL／500mL,转速300rpm,添加1．0％的丙酮可以使HA产量提高23．25％。丙酮可以作为一种有效的添加物应用于HA的生产。     

盐藻β-胡萝卜素提取及自由基清除能力研究

对盐藻β-胡萝卜素的微波提取工艺和提取液的自由基清除能力进行了研究。选择丙酮为提取溶剂,微波辅助提取盐藻β-胡萝卜素的最优条件为:微波功率500 W、液固比250 m L/g、提取温度40℃、提取时间8 min和搅拌速度180 r/min,此时盐藻β-胡萝卜素得率为1.13%,高于传统的溶剂浸提法;三种体外抗氧化体系（还原力、羟自由基清除能力和抗脂质过氧化能力）结果表明,微波提取和传统溶剂浸提得到的盐藻β-胡萝卜素提取液的还原力、羟自由基清除能力和抗脂质过氧化能力之间没有显著差异（p>0.05）,但2种提取液的自由基清除能力均高于同浓度的β-胡萝卜素标准品溶液,说明盐藻β-胡萝卜素提取液中还含有其他具有良好抗氧化活性的物质,但其自由基清除能力均低于同浓度的维生素C和BHT溶液。      

超声波辅助从浓缩磷脂中提取高纯粉状磷脂的研究

以大豆浓缩磷脂(CSP)为原料,丙酮为溶剂,提取高纯度粉状磷脂。针对传统有机溶剂法萃取制备粉状磷脂工艺过程中,物料粘度大,容易团聚成块,脱油操作极其困难,萃取效率低等问题,提出了超声波辅助均质萃取新技术。并对较佳的工艺操作条件的选择进行了研究。通过正交实验得出优化的条件为:萃取次数5次,萃取温度0℃,浓缩磷脂与丙酮之比为1/12g/mL,超声波辅助剪切转速5000r/min。产品丙酮不溶物可达98%以上。     

Antioxidant Activity of Mycelia from Aspergillus candidus

The antioxidant activity of mycelia extracts produced from the submerged cultures of Aspergillus candidus CCRC 31543 was investigated. Inhibition of peroxidation (IP%) of mycelia acetone extracts (MAE) in linoleic acid peroxidation was equal to that of BHA and significantly (p < 0.05) higher than that of α-tocopherol. As measured by the Rancimat method in lard, MAE showed marked antioxidant activity with an induction time of 8.4 h at a concentration of 200 μg/mL. MAE also exhibited strong scavenging effect on α,α-diphenyl-β-picrylhydrazyl radicals and marked reducing power. HPLC-DAD analysis suggested that MAE possessed the antioxidant components 3,3"-dihydroxyterphenyllin, 3-hydroxyterphenyllin, and candidusin B.