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.     

固体废弃物去除漂白废水中硅的试验研究

采用常温混合法和水热法，考察飞灰、高炉渣、高岭土在不同投加量下对漂白废水的除硅效果。结果表明：飞友除硅效果最佳，增大飞灰的投加量和延长反应时间，可有效改善飞灰对硅的去除效果，当固液比和反应时间分别为0．07g／mL和1h时，除硅率可达99％。飞灰除硅的主要有效成分为CaO，对含硅废水起钙刑脱硅的化合作用；高岭土除硅则主要是由于吸附作用；高炉渣仅在高温高压备件下才有一定的除硅效果；飞灰除硅产物中含有大量CaCO3，高炉渣反应后仍为无定形物，反应前、后高岭土结构未发生显著变化。     

Self‐Healing Inside APbBr3 Halide Perovskite Crystals

Self‐healing, where a modification in some parameter is reversed with time without any external intervention, is one of the particularly interesting properties of halide perovskites. While there are a number of studies showing such self‐healing in perovskites, they all are carried out on thin films, where the interface between the perovskite and another phase (including the ambient) is often a dominating and interfering factor in the process. Here, self‐healing in perovskite (methylammonium, formamidinium, and cesium lead bromide (MAPbBr₃, FAPbBr₃, and CsPbBr₃)) single crystals is reported, using two‐photon microscopy to create damage (photobleaching) ≈110 µm inside the crystals and to monitor the recovery of photoluminescence after the damage. Self‐healing occurs in all three perovskites with FAPbBr₃ the fastest (≈1 h) and CsPbBr₃ the slowest (tens of hours) to recover. This behavior, different from surface‐dominated stability trends, is typical of the bulk and is strongly dependent on the localization of degradation products not far from the site of the damage. The mechanism of self‐healing is discussed with the possible participation of polybromide species. It provides a closed chemical cycle and does not necessarily involve defect or ion migration phenomena that are often proposed to explain reversible phenomena in halide perovskites.     

牦牛绒过氧化氢/过硫酸铵脱色体系工艺优化及其机制

针对现有商业化牦牛绒脱色过程复杂、脱色时间长等问题,提出新型过氧化氢/过硫酸铵体系牦牛绒脱色工艺。在尽可能提高纤维白度的前提下尽量减少纤维损伤,通过单因素试验确定了脱色时间、过硫酸铵用量和试剂pH值,对脱色工艺进行探讨并与商业化脱色牦牛绒进行比较。结果表明:采用过硫酸铵质量浓度为400 g/L,试剂pH值为9,在室温下脱色为180 min可达到商业脱色牦牛绒的效果,脱色时间节省至原来的1/8;脱色机制分析发现,脱色过程中硫酸根自由基起主要作用,羟基自由基起次要作用。该脱色工艺简单,为牦牛绒高值化利用提供了新的解决方案。     

Organochlorine Formation in Tertiary Amine Catalyzed Pulp Bleaching

An oxygen delignified eucalyptus kraft pulp was bleached by applying a catalytic amount of a tertiary amine, 1,4-diazabicyclo[2,2,2]octane, and hypochlorous acid at varying pH, temperature, and time. The bleaching filtrate was analyzed for chloroform and AOX and the pulp for residual lignin, hexenuronic acid, and OX. In comparison with chlorine dioxide bleaching, the novel catalytic bleaching (pH < 6) generated only traces of chloroform and low contents of AOX and OX. Separate catalytic oxidations of authentic hexenuronic acid showed that it was a major precursor of chloroform. The results demonstrate a practical way to reduce organochlorine formation in pulp bleaching and provide new understanding on the reaction pathways that yield chloroform.