关于有效解决多组分沉积物问题的研究

纸厂中的沉积物通常含有多种组分,其主要来源于机械浆、回用纤维、涂布损纸以及过程添加剂等多种原料.通常这些沉积物中某一组分可作为沉积作用的主要引发剂,同时也可作为其他原料之间的粘合剂,因此对这种引发剂进行鉴定和处理对减少胶粘物的沉积具有重要意义.另一方面,在胶粘物沉积现象严重的过程中,其还可以帮助有效地鉴别二次胶粘物.然而,要准确鉴别这种引发剂还有一定的难度.作者对纸厂胶粘物的沉积、浆料、沉积机理以及沉积物本身的组成等进行了研究,以期建立一种可靠的方法,有效地鉴别目前以及将来引发沉积物沉积的引发剂.     

径向基函数网络在近红外光谱纸浆卡伯值测量的应用

为了提高制浆过程中的在线预测纸浆卡伯值的精度,提出采用径向基函数网络来建立纸浆卡伯值近红外光谱法在线测量模型。结果表明,这种算法由于既考虑到了近红外光谱响应的非线性因素,又可防止BP网络在建模时出现训练速度慢、容易陷入局部最小和“过拟合”的现象,利用这种网络建立的纸浆卡伯值测量模型与一元回归、多元回归、主成分回归等线性方法和BP算法相比,具有更高的预测精度。     

Efficient enzymatic synthesis of ampicillin using mutant Penicillin G acylase with bio-based solvent glycerol

To fulfill the industry demand of ampicillin enzymatic synthesis, immobilized mutant Penicillin G acylase and bio-based solvent glycerol were employed at high substrate concentration and low acyl donor/nucleophile ratio. After process optimization, good yield and low operation costs were achieved.     

A viewpoint on the gastrointestinal fate of cellulose nanocrystals

BackgroundCellulose nanocrystalline (CNC) particles possess unique functional properties such as vastly modifiable surface, considerable mechanical strength and acid resistance, as well as, high aspect ratio. CNCs have received great attention for application in diverse fields of technology including (composite) hydrogels fabrication for the gastric protection and enteral delivery of drugs and nutraceuticals.Scope and approachThe orogastrointestinal digestibility and absorbability of the orally administered CNCs is overviewed in the current article. At first, some surface charge-related characteristics of acid-isolated CNCs are communicated. Then, the biocompatibility and biodegradability of CNCs and CNC-reinforced hydrogels are reviewed, followed by presenting credible digestion and absorption scenarios. Finally, the post-absorption metabolism of CNCs is briefly debated.Key findings and conclusionsBacterial cellulose shows good biocompatibility and hemocompatibility. CNC oxidation provides biologically beneficial impacts; for instance, the TEMPO- and periodate-oxidized CNCs have been shown to regulate some blood metabolic variables and improve the degradability in simulated human blood plasma, respectively. Spherical and carboxyl-bearing cellulose nanoparticles can be isolated through ammonium persulfate digestion. The sphericity of particles results in faster cellular uptake. Negatively-charged CNCs are non-mucoadhesive and thus upon ingestion can penetrate into the buccal and intestinal mucosa. One may augment the absorption of CNCs by targeted receptor-mediated endocytosis. It was postulated that sodium bicarbonate secretion into the duodenum can alter CNCs surface chemistry and influence CNC interaction with gut microbiota.     

无皂型表面施胶剂的合成及在造纸中的应用

为开发质优价廉、环境友好的纸张表面施胶剂,用自制聚合物分散剂以苯乙烯、丙烯酸酯等为原料,不用有机溶剂合成了无皂产品(SSTOP)。IR、DSC分析表明,SSTOP是存在苯乙烯、丙烯酸酯等单体链节的共聚物。粒径分布和TEM分析表明,SSTOP微粒大小均一、呈核壳球状。在造纸厂的中试应用结果表明,在白纸板上,SSTOP与德国无皂产品BK-350效果相当,而每吨产品便宜700元。双胶纸上无皂型SSTOP与含乳化剂产品相比,处理纸张正、反面纸张表面吸水值分别降低10.2%、14.3%,表面强度提高20.8%和21.1%。     

A large pore-size mesoporous zirconia supported cobalt catalyst with good performance in Fischer–Tropsch synthesis

Mesoporous zirconias with different pore sizes have been prepared by controlling the synthesis conditions including the pH of the synthesis system and the amount of diglycol added in the initial system. It was found that the F–T catalytic performances strongly depended on the pore sizes of mesoporous zirconias. The cobalt catalyst supported on such a mesoporous zirconia with the pore-size of 9.1 nm showed better catalytic performance in F–T synthesis, especially, displayed higher selectivity to C₁₂–C₁₈ paraffin as the main component of diesel oil fraction as compared to an amorphous SiO₂ with the close pore size. The above result was attributed to the combination of improvement of mass transfer derived from the large pore size and narrow pore size distribution of the mesostructure with the particular reactivity from the zirconia support.     

机械浆中胶体树脂沉积行为及影响因素

以脂肪酸、树脂酸、甘油三脂为模型物，研究了不同树脂组分、pH值、钙离子和温度对树脂沉积行为的影响，以及在钙离子存在下pH值对酸性组分沉积物组成的影响。结果表明，无钙离子存在时，低pH值时树脂沉积较严重，随pH值的升高，沉积趋势降低；钙离子的存在，加剧了树脂的沉积。pH值是影响酸性组分形成钙皂的关键因素，低pH值时沉积物中几乎不含有钙皂，随pH值的升高，沉积物中钙皂的含量提高，并且沉积物的黏性显著增加。甘油三脂沉积物中几乎不含无机成分，但在pH值4．5～8．5范围内，钙离子的存在明显加剧了其沉积行为。温度对树脂酸组分影响较大，温度升高，树脂酸黏性提高，沉积性增加。     

提高芦苇SCMP过氧化氢漂白效率的研究

对芦苇磺化化学机械浆（SCMP）H2O2漂白过程中的各种影响因素进行了探讨，确定了芦苇SCMP H2O2漂白的适宜工艺条件。实验结果表明，芦苇SCMP具有较好的可漂性，采用2％用量的H2O2就可以将白度为40．6％ISO芦苇SCMP漂至52．4％ISO。     

漆酶用于硫酸盐竹浆TCF漂白的研究

利用3种漆酶或漆酶/介体系统处理硫酸盐竹浆,并进行TCF漂白.结果显示,与传统的CEH漂白相比,硫酸盐竹浆进行包括漆酶/介体系统处理的OLQP白,在达到相近白度情况下,纸浆强度损失小;3种不同漆酶在HBT存在下的TCF漂白浆比CEH漂白浆黏度高43.3%～56.2%;从白腐菌HG产生的漆酶在HBT存在下处理硫酸盐竹浆,经OLQP漂白后,浆的白度可达80.7%ISO,黏度在800mL/g以上.在没有外加介体的情况下,该漆酶处理纸浆仍具有较好的脱木素效果,经OL0QP(L0,无外加介体)漂白后,纸浆白度可达76.7%ISO,比OQP漂后的浆白度提高了23.2%ISO.