DETECTION OF T_g BY MODULATED DIFFERENTIAL SCANNING CALORIMETRY

The glassy transition of the polyethylene terephthalate (PET) sampleswhich have been subjected to solvent induced crystallization (SINC) was investigated bymodulated differential scanning calorimetry (MDSC) and density measurement. The dif-ferential of heat capacity signal, d C_p/dT from MDSC, was used to monitor the SINCprocess. It reveals that the T_g temperature shifts to higher value with the advancement ofSINC. When the toluene-immersing time was longer (168h), the detection of T_g becomemore difficult, because some smaller peaks emerged at the lower temperatures and theseare explained as the movement of small segments in the amorphous region. These observedresults are due to the morphology and structure introduced by the SINC process.     

A Novel Photoproduct of 1, 3-Dimethyluracil in Phosphate Buffered-saline

1, 3-Dimethyluracil （DMU） in phosphate buffered-saline （PBS, pH=8） was irradiated by a medium pressure mercury lamp （MPML） and produced a novel compound C6H9N2O6P. The composition and structure of the compound has been identified by elemental analysis, EIMS, UV, IR, ^1H and ^31P-NMR.     

液相色谱-串联质谱法同时检测饲料中多种抗氧化剂

饲料中添加抗氧化剂能够阻止或延缓饲料中某些营养物质氧化,延长饲料贮存期,从而提高饲料利用率.     

苯乙烯－甲基丙烯酸共聚物和聚环氧丙烷共混体系的相容性研究

 本文用傅里叶交换红外光谱法（ＦＴＩＲ）表征了苯乙烯－甲基丙烯酸共聚物Ｐ（Ｓ－ＭＡＡ）和聚环氧丙烷（ＰＰｒＯ）共混体系的相容性．用谱带分离的技术比较准确地测定了共混体系中几种羰基的吸光系数比，并且用简明的方法定量计算了它们之间平衡的平衡常数．同时实验还表明共混组分中聚醚的分子量、分子结构、Ｐ（Ｓ－ＭＡＡ）中ＭＡＡ的含量以及共混组分的比例和体系的相容性有密切的关系．     

Confined space-controlled hydroperoxidation of trisubstituted alkenes adsorbed on pentasil zeolites

Photosensitized oxidation of trialkylalkenes 2-methyl-2-pentene (1), 1-methylcyclohexene (2), trans-3-methyl-2-pentene (3), cis-3-methyl-2-pentene (4), and 2-methyl-2-butene (5) included in the internal framework of Na-ZSM-5 zeolites was investigated. The zeolite samples having adsorbed the alkenes were suspended in isooctane, and the sensitizer, tetraphenylporphyrin (TPP), was dissolved in the solution. Singlet oxygen produced in the solution diffused into the internal framework of the zeolites and reacted with alkenes. For all the substrates studied, the ene-type allylic hydroperoxides were obtained in a highly regioselective manner. The regiochemistry for 1-4 in favor of the allylic hydrogen abstraction from the largest substituents is in contrast to their photooxidation within the dye-supported zeolite Na-Y, where the secondary hydroperoxides are preferentially produced. The tight confinement of the alkenes within the narrow channels of the ZSM-5 zeolites is likely to be responsible for this selectivity.     

羧甲基壳聚糖对胆红素的吸附性能研究

合成了不同取代度的羧甲基壳聚糖(CM-CTS)作为吸附剂，研究了不同条件对CM-CTS吸附胆红素性能的影响．结果表明：在实验条件下，随着羧甲基取代度的增加和体系温度的升高．最大吸附率和吸附速率均相应增加：在接近人体血液pH值的条件下，CM-CTS对胆红素的吸附性能较佳：人血清白蛋白和离子强度的增加对CM—CTS吸附胆红素有明显的抑制作用。     

Yb(C~6Me~6) (AlCl~4)~3·MeC~6H~5 的合成及其晶体结构

合成了一种新的芳烃络合物Yb(C~6Me~6)(AlCl~4)~3·MeC~6H~5 , 并确定了其晶体结构.     

双波长薄层紫外可见光谱电化学测定多巴胺

多巴胺 (DA)和抗坏血酸 (AA)的吸收光谱在 2 0 0～ 30 0nm内重叠严重 ,但在电化学氧化状态下 ,DA的氧化产物在 2 10 ,30 0和 4 80nm有强吸收峰 ,AA的氧化产物在 2 0 0～ 4 0 0nm范围内吸收较弱且呈光滑平缓的斜坡。在此基础上 ,利用自行设计的长光程薄层光谱电化学池建立了一种双波长光谱电化学法测定DA。测定条件为 pH 6 .2的磷酸盐缓冲液 (PBS) ,0 .6V (vs.Ag/AgCl)电极电位 ,双波长 318/ 2 93nm ,线性范围为 4 .0× 10 - 6 ～ 2 .0× 10 - 4mol·L- 1,检出限为 2 .0×10 - 6 mol·L- 1。对 6 .2 0× 10 - 5mol·L- 1DA进行 11次平行测定 ,平均相对偏差为 2 .6 %。与文献报道的吸光光度法相比 ,该法具有较高的灵敏度和选择性 ,较为有效地消除了AA的干扰 ,回收率在 91.8%～ 10 0 .8%之间 ,结果满意     

吸热型碳氢燃料在银、镧改性混合分子筛上的裂解研究

为进一步提高吸热型碳氢燃料的吸热能效，考察了吸热型碳氢燃料NNJ－150在USHY和HZSM－5混合分子筛以及银、镧改性混合分子筛催化剂上的催化裂解。结果表明，在Ag-LaUSY Ag-LaZSM-5(75:25)混合分子筛催化NNJ－150裂解反应中，低碳烯烃选择性较高，催化剂寿命较长。采用此催化剂，能较好满足吸热型碳氢燃料裂解的需要。