Reaction of sodium perborate with a chlorinated cyclic hindered amine (TMP-Cl): I. Quantitative evaluation of active oxygen species in fabric bleaching

The reaction of N-chloro-4-hydroxy-2,2,6,6-tetramethylpiperidine (TMP-Cl) with sodium perborate (PB) was investigated with special reference to the generation of singlet oxygen and the possible application to a new oxidative bleaching process. Generation of the singlet oxygen (¹O₂), the hydroxyl radical (HO·) and superoxide anion radical (O₂·⁻) in the PB/TMP-Cl mixed solution was confirmed by the trapping reagent method. From the results of another experiment, in which the bleaching abilities of each active oxygen species were confirmed, the main active oxygen species contributing to the bleaching of purpurogallin, the skeleton of black tea pigment, in the PB/TMP-Cl system was concluded to be¹O₂.     

金属蛋白助剂在大豆蛋白纤维过氧化氢漂白中的应用研究

探讨了金属蛋白助剂质量的浓度、过氧化氢质量浓度、硅酸钠等其它助剂质量浓度及漂白温度、漂白时间等因素对大豆蛋白纤维漂白效果的影响,确定出了金属蛋白助剂在过氧化氢漂白大豆蛋白纤维应用中的最佳催化漂白工艺,其为:金属蛋白助剂为2g/L,30%过氧化氢为15ml/L,硅酸钠为6g/L,精练剂为0.13g/L,在75℃下保温处理60min。并评价催化漂白新工艺的效果。结果表明,加入适量金属蛋白助剂可以提高过氧化氢对大豆蛋白纤维漂白的白度,并且提高纤维的保水率,但与未处理纤维相比,催化漂白新工艺处理的纤维强力降低了4.25%,断裂伸长率增加17.65%。     

碱法麦草浆木聚糖酶处理后木质素及碳水化合物的变化

采用UV光谱、凝胶色谱、X—射线衍射及扫描电镜等技术对碱法麦草浆的酶解浆和酶解液进行分析,探讨了木聚糖酶对碱法麦草浆处理后浆中木质素和碳水化合物的变化情况。研究认为,木聚糖酶对碱法麦草浆漂白作用主要是因为木聚糖酶降解了浆中部分木聚糖和残余木质素中的LCC结构,从而使后序漂白中漂液更易渗透,木质素的溶出更多、更易。     

脱色剂对碱炼大豆油酸值和过氧化值的影响

食用油脂加工过程中,脱除色素的同时能降低酸价和过氧化值.研究发现,不同吸附剂对油脂脱色、酸价、过氧化值的影响有差异,活性炭与活性白土配合使用,85℃脱色15~20 min时,脱色率提高明显,并能最大限度地降低酸值和过氧化值,改善风味,提高油品品质和稳定性.     

亚麻棉纱练漂工艺实践

采用氯漂和氧漂相结合的前处理工艺,在氧漂中用尿素代替烧碱,使亚麻棉纱的白度达到了客户要求,且强力下降不多。     

四种相思树硫酸盐法制浆性能的比较

系统研究了大叶相思、马占相思、厚荚相思及纹荚相思4种相思树的材料特征、化学组分,采用硫酸盐法对比研究了4种相思树的制浆性能,并采用CEHD四段漂白程序对4种相思树纸浆进行了漂白性能的研究。结果表明,4种相思树都是制取漂白硫酸盐浆的适宜阔叶材种;采用硫酸盐法制浆,用碱量(氧化钠计)为16%,硫化度为25%时,纸浆得率为46.95%～50.95%;制得的4种相思树硫酸盐浆经CEHD四段漂白,在总有效氯用量控制在5.1%时,纸浆白度为81.5%ISO～84.7%ISO;纸浆的强度性能良好,叩解度为30°SR时,其抗张指数为59.4～63.7N·m/g。综合比较,4种相思树的制浆性能优劣顺序为:马占相思>大叶相思>纹荚相思>厚荚相思。     

基于神经网络的统计优化方法及其在纸浆漂白工艺中的应用

应用三层前向网络作为预测纸浆漂白效果的分类模型。在网络能正常识别漂白效果所属类别的基础上，通过模拟计算和统计分析，确定了漂白工艺参数的优化操作区域。这为难以建立精确数学模型又是多约束的漂白工艺过程的优化提供了一种有效方法。     

两种偏钛酸漂白工艺的对比

通过对偏钛酸铝粉漂白工艺和三价钛漂白工艺在原理、漂白后效果及经济成本方面的对比分析，阐明了三价钛漂白工艺优于铝粉漂白工艺。     

The influence of specimen refractive index,detector signal integration,and non-uniform scan speed on the imaging properties in confocal microscopy

Refraction of light in a specimen volume may cause aberrations that influence the imaging properties in confocal microscopy. In this paper the influence on three-dimensional resolution and geometry is experimentally investigated for a uniform specimen volume. It is found that the depth resolution is more severely affected than the lateral resolution. This is unfortunate, because even under ideal conditions the depth resolution is lower than the lateral resolution. Lateral image geometry is little affected by the specimen refractive index, whereas the depth scale can be considerably elongated or compressed. The influence of a finite detector integration time is also considered. This can give a noticeable, but not particularly severe effect on the image resolution in the line-scan direction. Because the integration time can be accurately controlled, a shorter integration time can be used when maximum resolution is essential, albeit at the price of a higher noise level. In scanning fluorescence microscopy a non-uniform scan speed may give large variations in bleaching over the specimen surface. Experiments illustrate how serious such non-uniform bleaching effects can be when a specimen area is repeatedly scanned, for example when recording optical serial sections.