大孔树脂分离纯化燕麦麸皮多酚的研究

从10种大孔吸附树脂中筛选出D101树脂,并研究其对燕麦麸皮多酚静态与动态的吸附及解析性能。试验表明,D101树脂对燕麦麸皮多酚的静态饱和吸附量为64.01 mg/g(干树脂),饱和吸附时间为5 h,解吸剂乙醇溶液的适宜体积分数70%。以质量浓度为3.046 mg/mL,流速为1.0 mg/min燕麦麸皮提取液上柱时,树脂的多酚穿透吸附容量63.28 mg/g(干树脂),60 mL体积分数70%的乙醇溶液可将吸附于柱上的燕麦麸皮多酚基本完全洗脱。结果显示,D101树脂的吸附和解析性能较好,适合于燕麦麸皮多酚的纯化。     

硼改性核桃壳生物基酚醛树脂的制备与性能研究

以核桃壳经苯酚液化后的液化产物、硼酸、多聚甲醛为原料,通过固相法合成硼改性核桃壳生物基酚醛树脂（BWPF）,用傅立叶红外光谱（FTIR）分析其结构,扫描电镜（SEM）观察其自然断面形貌,差示扫描量热法（DSC）与热重分析法（TG）分析其热性能。结果表明：硼酸与核桃壳液化产物中的酚羟基发生反应生成新的交联,随着硼酸加入量的增加,硼改性核桃壳生物基酚醛树脂韧性和固化温度得到提高;随着硼酸加入量的增加、反应温度的提高和反应时间的延长,硼改性核桃壳生物基酚醛树脂炭残余质量有所增加,耐热性能提高。     

大孔吸附树脂纯化羟基红花黄色素A的研究

[目的]探讨大孔吸附树脂对红花提取物的最佳纯化条件及纯化效果,为羟基红花黄色素A的工业化高效生产奠定基础。[方法]以羟基红花黄色素A（HSYA）作为考察指标,通过羟基红花黄色素A在6种商品化树脂上的吸附量和解吸率筛选树脂的种类,以收率和纯度为指标考察上样液的吸附流速、pH值及浓度,洗脱液的浓度、流速等纯化条件。[结果]采用HPD-400作为吸附树脂,50%乙醇作为洗脱液,pH值为3的红花提取液,上样吸附流速为6 BV/h,洗脱流速为8~10 BV/h时纯化效果较好,在该条件下HSYA的收率为73.8%,纯度为35.7%。[结论]大孔吸附树脂法优化纯化条件后,提高了羟基红花黄色素A的纯化效果,这为羟基红花黄色素A的工业化高效生产提供了理论依据。     

大孔树脂提纯竹叶黄酮的吸附解吸动力学研究

通过对4种大孔吸附树脂吸附率及解吸率的测定,确定最佳型号树脂;通过静态和动态吸附解吸动力学研究,确定大孔树脂吸附法分离竹叶黄酮的最佳工艺条件。结果表明,AB-8型大孔树脂吸附量大,易于洗脱,纯化分离效果好。获得最佳分离纯化工艺参数为：上柱溶液pH为5．0,以1．0mL/min的吸附流速上样,用4倍床体积的60％乙醇以1．5mL／min洗脱速率洗脱。该工艺生产的竹叶黄酮纯度达到54．16％。     

球状壳聚糖树脂对茶多酚的吸附热力学和动力学研究

采用反相悬浮交联法制备了球状壳聚糖树脂(RCM),通过静态吸附实验,研究了RCM对茶多酚的吸附热力学和动力学特性。结果表明:吸附等温线符合Laugmiur等温曲线,且平衡常数Kb随着温度升高而升高。吸附是非自发的、吸热的、熵增加的过程。吸附过程符合二级动力学吸附模型,吸附过程主要受粒子内扩散模型控制。     

不同型号大孔树脂对黄芩苷纯化工艺的研究’

以黄芩苷含量为考察指标,从静态吸附-解吸、动态吸附-解吸两方面筛选最适纯化树脂,确定最佳纯化工艺参数。研究表明HPD-100大孔树脂为最适树脂,黄芩提取液在该树脂上吸附阶段的泄露点为3.0BV,饱和点为12.5BV;解吸阶段的适用乙醇浓度为50%。该工艺可用于黄芩苷的精制纯化,显著提高黄芩苷的提取率。     

香椿叶抗脂质过氧化物的分离及抗氧化特性

为寻求有应用前景的油脂抗氧化剂,分离纯化香椿叶中抗脂质过氧化物（FTAP）,研究pH值、热处理及贮藏对FTAP抗氧化活性的影响及FTAP在油脂中的应用。FTAP的抗氧化活性用亚油酸过氧化法测定。采用大孔树脂分离纯化FTAP,比色法测定FTAP中的黄酮类含量。以FTAP对亚油酸过氧化抑制率反映其在不同pH值介质、热处理以及贮藏期的抗氧化性。用过氧化值评价FTAP在油脂中的抗氧化作用。结果表明,LSA-10树脂适于FTAP的分离纯化,FTAP抗脂质过氧化作用与其黄酮含量有关;FTAP在pH 7、pH 4时抗氧化活性较强,185℃下加热60 min抗氧化性无显著变化,5℃下贮存30 d抗氧化性稳定,而后逐渐降低;FTAP能抑制猪油和菜籽油的氧化,且呈量效关系,0.02%FTAP与0.02%BHT抗氧化活性相当。FTAP是具有潜力的天然抗氧化剂,可用于油脂或含油脂食品中。     

环氧树脂作还原剂制备Li3V2(PO4)3的结构和性能

采用高温固相法，以环氧树脂为还原剂合成锂离子电池正极材料Li3V2(PO4)3.通过X射线衍射分析和扫描电子显微镜对样品的晶体结构和微观形貌进行表征，并用恒电流充放电和循环伏安实验研究材料的电化学性能.结果表明所制备的Li3V2(PO4)3为结晶完善的单斜结构，颗粒分布均匀且粒径较小，0.2 C时在3.0V~4.3V电压范围的首次放电比容量为126.9 mAh/g，30次循环后的比容量为126.0 mAh/g，容量保持率达到99.29%.     

Nitrogen dynamics in different types of pasture in the Austrian Alps

 Soil N dynamics were compared in Alpine pastures on two mountains. N-pool sizes and N fluxes were measured relative to N losses via leaching and denitrification in summer. On each mountain, four types of pasture were studied: (1) forest pastures, (2) recently developed pastures formed by forest clearance ("new pastures"), (3) older established pastures, and (4) pastures planted with clover. At both study sites (Scheuchegg and Teufelstein) we obtained similar results. Compared with forest pasture soils, open pasture soils were found to have greater microbial biomass and faster mineralisation potentials, but net field mineralisation rates were slower. In the forest pastures, highest N losses via denitrification were found. Higher potential leaching of NO₃ ^–, estimated by accumulation of NO₃ ^– on ion-exchange resins, in the forest pasture soils suggests lower N uptake by microbes and herbaceous plants compared with open pastures. N₂O-production rates of the forest pasture soils at the Scheuchegg site (11.54 μg N₂O-N m^–2 h^–1) were of similar magnitude to those reported for spruce forests without pastures, but at Teufelstein (53.75 μg N₂O-N m^–2 h^–1) they were higher. However, if forest pastures are not overgrazed, no elevated N loss through N₂O production and leaching of NO₃ ^– is expected. Denitrification rates in the open pastures (0.83–7.50 μg N₂O-N m^–2 h^–1) were low compared with reports on lowland pastures. In soils of the new pastures, rates of microbial N processes were similar to those in the established pastures, indicating a high capacity of soils to restore their internal N cycle after forest clearance. Received: 19 August 1999     

粉状酚醛树脂胶粘剂性能指标体系建立及评价

粉状酚醛树脂胶粘剂的制造和应用越来越受到木材工业界的重视，为此从物理几何性能、力学性能、工艺性能3方面建立粉状酚醛树脂胶粘剂的性能指标体系，并讨论建立这些性能指标的依据和参考标准及测试方法，在此基础上，测试了5种粉状酚醛树脂胶粘剂的常规性能．