Diffusion of lignin macromolecules within the fibre walls of kraft pulp. Part I: Determination of the diffusion coefficient under alkaline conditions

The intrinsic rate of diffusion of soluble lignin from fibre walls to bulk liquor has never been determined previously because of experimental difficulties; for example, the diffusion rate determined in a stirred cell is affected by the mechanical action of stirring. In our work, the intrinsic rate of diffusion of lignin macromolecules from the fibre walls of a softwood kraft pulp was determined under alkaline conditions using a displacement cell which eliminated external heat and mass transfer resistances and pulp fibre disturbances. The effects of such experimental conditions as pulp bed height and liquid flow rate were studied. The diffusion rate can be described by a diffusion model for a hollow cylinder with a very wide range of diffusion coefficients. The diffusion rate increased with increasing pH. Our results provide a new understanding of the lignin diffusion process in fibre walls, which is affected by the size of lignin molecules and the pores, and by the electrostatic interactions between intrafibre pore walls and lignin.     

微晶纤维素增粘剂的研制

以棉浆为原料，废盐酸为水解催化剂，所得合成革用微晶纤锥素增粘剂的质量指标达到了德国和日本同类产品的标准。     

无动力快速浮选在山东某黄金矿山的应用

山东某黄金矿山选矿厂由于浮选工艺流程中旋流器与取样机之间高差较大,以致溢流矿浆流速快、动能大,易造成对管路、弯头及取样机缓冲箱的冲击磨损。鉴于此,在旋流器溢流进入浮选粗选前增加快速浮选槽,以充分利用矿浆的动能,将原浮选工艺流程前增设无动力快速浮选工艺,并对改造后工艺流程结构进行了优化,将原三次扫选改为二次扫选。无动力快速浮选工艺的应用,不但节约了能耗,而且提高了金回收率,其由改造前的91.69%提高到93.06%,生产指标较好。     

基于模糊免疫PID的纸浆漂白过程控制算法研究

利用模糊技术的非线性特点和生物系统的免疫反馈原理,提出基于模糊免疫的PID控制器,该控制器根据控制量的变化自适应调整比例系数。仿真结果表明,该控制器具有良好的跟踪输入能力和满意的控制效果。目前,该算法已经成功应用于某造纸厂的漂白工段,一定程度上提高了漂白后的纸浆质量,取得了较好的经济效益。     

光学方法检测牙髓活力

介绍了用光电体积描记器、脉冲血氧定量计、激光多普勒流量计等光电技术检测牙髓活力.对于中老年患者,牙龈中的血管比牙髓中发达,牙龈中产生的信号超过了牙髓,所以建立一种有效的光学探测途径相当困难.     

漂白麦草浆细杂组份对阳离子淀粉吸附的影响

本文研究了漂白麦草浆中细杂组份(通过100目,其中大部分是杂细胞,如薄壁细胞,表皮细胞)对阳离子淀粉吸附的影响。 实验表明,漂白麦草浆中细杂组份的比表面积明显大于纤维组份(保留在100目以上)的比表面积。阳离子淀粉优先吸附在比表面积大的细杂组份上。纤维组份的吸附能力受化学环境的影响较细杂组份更为敏感。     

钢球表面罩盖层厚度的影响因素研究

本文探讨了湿式磨矿过程中钢球表面罩盖层厚度的影响因素及其影响规律。研究结果表明,钢球表面罩盖层厚度随矿浆体积浓度的增大而增大,且存在一临界值（约为50％）,当矿浆体积浓度大于该临界值时,罩盖层厚度急剧增大,矿浆体积浓度越高,增大的幅度越大;添加化学药剂能改善高浓度矿浆的流变性,使钢球表面出现最佳罩盖层厚度所对应的矿浆体积浓度增大;当矿浆性质一定时,罩盖厚度与矿浆流速有关。     

The yield stress of fibre suspensions

Yield stresses were determined for commercial wood pulp suspensions and synthetic fibre suspensions of low and medium mass concentration. The yield stresses measured represent interfibre failure of the network rather than failure between the suspension and a solid surface. The measurements were carried out in a rotary viscometer at low yield stresses and in a concentric rotary shear tester at yield stresses in excess of 2500 Pa. The experimental results were correlated with the volumetric concentration C_v in equations of the form τ_y = aC^b_v where a and b are constant for a given fibre type. It was found that b ? 3, in agreement with the predictions of a theoretical model of fibre network strength based upon the interlocking of elastically bent fibres. The dependence of the yield stress on the fibre properties of aspect ratio and modulus of elasticity was not adequately predicted by the model, suggesting that fibre bending alone did not account for the network strength over the concentration range studied.     

杨木爆破浆作新闻纸配浆的初步研究

进行了杨木爆破浆配抄新闻纸的研究，杨木爆破浆取代马尾松化学浆配抄新闻纸后除撕裂度略有下降外，裂断长、拉毛速度、印刷密度、透印值等都有明显改善     

无性系速生杉木的化学组成及其高聚糖在蒸煮过程中溶出特性的研究

本文比较分析了五个无性系速生杉木变种之间以及变种与原种之间的化学组成，并且对生长速度最快的杉木变种的高聚糖在蒸煮过程中的溶出特性也进行了探讨。研究结果表明：杉木各变种之间的化学组成没有引起很大的变异，但与杉木原种相比是有差异的。组成杉木变种的高聚糖中各种单糖在ＫＰ和ＫＰ－ＡＱ法蒸煮过程中的溶出百分率有如下顺序：葡萄糖＜甘露糖＜木糖＜阿拉伯糖＜半乳糖＜糖醛酸。碳水化合物的总损失ＫＰ法为３８．４９％，而ＫＰ－ＡＱ法为３４．８５％。在１７０℃以前，失去的碳水化合物主要来自半纤维素；而在１７０℃以后，则主要来自纤维素。由此看来，缩短保温时间有利纸浆的质量。成浆高聚糖的ＤＰ，ＫＰ法为８８９，ＫＰ－ＡＱ法为９２４，因此ＫＰ－ＡＱ法比ＫＰ法更适合于速生杉木制浆。