电石生产碳素原料中掺加无烟煤对生产的影响

根据无烟煤的特点,在电石生产碳素原料中掺加价格相对较低的优质无烟煤,提高炉料比电阻,从而达到提高热效率和电效率,降低电石成本的目的。     

Effect of the degree of branching on the glass transition temperature of polyesters

Glass transition temperature dependence on the branching degree can be empirically estimated by excluding additional effects on this parameter as molecular weight distribution, end group interactions or crystallization. In this communication aliphatic–aromatic polyesters with a well defined degree of branching between 0% (linear) and 50% (hyperbranched) are investigated by differential scanning calorimetry. The hydrogen bonding effect of the OH-terminal groups was successfully extracted from the pure branching effect by protection of the end-functionalities. Fractionation of samples with variation of the branching degree and end-functionalities led to series of narrowly distributed molar masses. The dependence of the molecular weight on the glass transition temperature for different branching degrees was calculated and compared for polar and non-polar end groups.     

Chemical oxidation of residual carbon from ZnAl2O4 powders prepared by combustion synthesis

The removal of carbon residue from ZnAl₂O₄ nanopowders by annealing at 500–800 °C leads to a decrease of specific surface area from 228.1 m²/g to 47.6 m²/g. At the same time, the average crystallite size increased from 5.1 nm to 14.9 nm. In order to overcome these drawbacks, a new solution for removing the carbon residue has been suggested: chemical oxidation using hydrogen peroxide. In terms of carbon removal, a H₂O₂ treatment for 8 h at 107 °C proved to be equivalent to a heat treatment of 1 h at 600 °C. The benefits of chemical oxidation over thermal oxidation were obvious. The specific surface area was much larger (188.1 m²/g) in the case of the powder treated with H₂O₂. The average crystallite size (5.8 nm) of ZnAl₂O₄ powder treated with H₂O₂ was smaller than the crystallite size (8.2 nm) of the ZnAl₂O₄ powder annealed at 600 °C.     

用低烟无卤阻燃剂聚烯烃材料制造复合编织布研究

概述:传统的塑料包装布主要是聚烯烃塑料编织布,其中的高聚物属易燃、可燃材料,在燃烧时热释放速率大、热值高、火焰传播速度快、不易自熄、延燃性强,燃烧时还会产生浓烟或有毒、有害、有腐蚀性的气体,对环境造成二次性危害,对人的生命安全带来巨大的威胁。此种编织布遇火极易引起燃烧,故适用范围受到限制。     

Physical and mechanical properties of concretes produced with waste concrete

Because of the damage they do to buildings, natural disasters such as earthquakes produce large amounts of waste concretes. Carrying waste materials away from the disaster site causes financial and environmental problems, so people try to recycle the waste concretes as aggregate in order to prevent these problems. Using waste material that was obtained from razed buildings and then was cleaned and later reduced to aggregate form is considered an appropriate solution to environmental pollution. In this study, various physical and mechanical properties of concretes were examined. These concretes were produced by the addition of C 16 (28-day compressive strength of 16 MPa) pieces as aggregate in weight percentages of (referred to total aggregate) 0, 30, 50, 70, and 100%. In the concretes, it was observed that as the amount of WCA increases, density, workability, Schmidt hardness, ultrasound velocity, and compressive strength decrease.     

Enhancements in sugar immobilization in polymeric macroporous matrices for affinity capture

The use of macroporous monolithic matrices in the purification of biocompounds is constantly growing and developing. In this work, the objective was to optimize the quantity of N-acetyl-D-glucosamine (D-GlcNAc) immobilized on the surface of macroporous polymeric cryogels for capture of lectins from less clarified solutions. Surface response methodology was applied and it was observed that the immobilization temperature of the glutaraldehyde (GLU) and the D-GlcNAc concentration influenced the amount of sugar immobilized. The matrices produced with 1.1% of allyl glycidyl ether were functionalized by GLU. Optimal maximum condition was obtained with mean value of 160.39 ± 26.38 mg of D-GlcNAc immobilized per gram of dry cryogel. Characterization analyses of the matrices showed that the activation process was effective, maintaining the macroporous structure and physical characteristics. The adsorbents produced were tested for capture of lectins from a crude protein solution of barley. At tested conditions, adsorbent capture around 11% of protein in solution but reduce the hemaglutinating capacity in 40%, demonstrating its selectivity. The cryogels functionalized with D-GlcNAc present potential for use in capture compounds by affinity with carbohydrates, such as lectins. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47956.     

定尺剪废料收集系统的结构改造及应用

介绍了莱钢4300mm厚板剪切设备的废料收集系统在生产中出现的问题,针对缺陷在结构上进行了改造,达到了满意的效果。     

定尺剪剪切精度的影响因素和改善措施

介绍了4300mm宽厚板定尺剪的结构和组成,分析了影响定尺剪剪切精度的主要原因,并提出了提高定尺剪剪切精度的措施。经过改进后,定尺剪剪切误差控制在1％o以内。