基于温度冲击的冷冻靶氘氘冰层结晶生长行为研究

惯性约束聚变冷冻靶中氘氘（D₂）冰层的质量对聚变实验的成功与否起重要作用。目前文献报道的制备冷冻靶D₂冰层的方法并不具备好的可操作性，且技术、工艺不定型，制约了高质量冰层的形成。因此，本文采用将温度梯度、降温速率和温度冲击相结合的技术实现燃料冰层在靶丸内的均化。通过温度控制以及施加温度冲击可控地形成残留冰，并在残留冰的控制技术基础上，实现了高质量冰层的可控结晶生长。同时，研究了温度控制对靶丸内D₂冰层品质的影响和D₂冰层结晶生长的过程，并应用晶体生长动力学理论分析了D₂冰层结晶生长行为。从背光阴影图像中的D₂冰层亮环可知，D₂冰层均匀度为85.2%、厚度为40.35 μm、内表面粗糙度为2.15 μm。本方法拓宽了超低温下D₂冰籽晶控制、晶体生长技术，为DT冷冻靶中冰层均化打下了坚实基础，并形成了一定的技术储备。     

基于VRS技术的煤矿地表变形监测实践研究

随着采深的增大,晋华宫矿开采过程产生严重的地表沉降问题,对该矿地面建构及设施造成了安全隐患。该矿选择采用虚拟参考站技术(VRS技术)来对地表沉降进行测量监测。监测结果表明,VRS技术具有更好的准确性和科学性,在监测过程中表现出测量范围广、工作效率高、工作量小的特点,可以对该矿地表沉降问题进行有效监测。     

强化研磨加工中喷射角度对GCr15轴承钢板塑性变形的影响

利用ABAQUS有限元仿真软件研究不同喷射角度强化研磨加工GCr15轴承钢板过程的塑性变形,得到不同喷射角度与等效塑性应变沿真实路径距离的关系,并通过拉伸试验进行验证。喷射角度为90°的强化研磨加工伸长率为1.4%,相比未经过强化研磨加工的伸长率数值缩减了2.0%。断口收缩率由空白组的4.9%降低到喷射角为90°的2.2%。结合仿真和试验可知,强化研磨加工中喷射角度越大,塑性变形能力越低,材料加工越难。     

铝金属化纸制备工艺的专利技术发展

通过对铝金属化纸领域专利技术的收集、分析、标引,介绍了铝金属化纸的制备方法及种类,包括铝粉涂布、铝箔纸以及可降解回收的真空镀铝纸等;并对其专利申请量、区域分布以及渡铝技术进行了分析,同时对各技术的发展历程和改进情况进行了梳理归纳。     

Evaluation and verification of the virgin–recycled mixing ratio of polypropylene plastic

This study has analyzed the properties of blended polypropylene (PP) specimens and employed statistical analysis to develop a method for determining the virgin–recycled mixing ratio of a specimen. Morphological observations and analyses of thermal and mechanical properties were conducted to examine specimen properties. The results were incorporated into regression analysis to create relationship equations. The results revealed that the melt temperature ranged between 167 and 169 °C, melt index (MI) ranged between 7.59 and 18.36 g/10 min, viscosity decreased when the amount of recycled PP and the rotation speed increased, the maximum decomposition temperature decreased with an increase in recycled PP content and increased with the heating rate, activation energy (E_a) ranged between 39.91 and 12.07 kcal/mol, Young’s modulus ranged between 1121.1 and 1910.2 MPa, and impact strength ranged between 37.94and 49.41 J/m (no significant trends). Scanning electron microscopy showed unbroken fibrils distributed on the fracture surface of Specimens 1–3. Additionally, the tensile strain of these specimens was comparatively high. The fracture surfaces of the specimens showed favorable compatibility after undergoing impact tests. The results of regression analysis indicated that the mixing ratio achieved significant correlations with E_a, MI, and Young’s modulus. Thus, regression and multiple regression analysis were performed to create relationship equations.     

High‐performance printable paper‐like composites derived from plastic flexible film wastes

Owing to lack of proper recycling methods, plastic flexible film wastes are usually directly discarded or incinerated, which brings about severe environmental pollution. Therefore, converting plastic wastes into value‐added products has received more and more attention in recent years. In this work, paper‐like composites derived from plastic flexible film wastes were prepared via the thermally induced phase separation method by adding polyethylene‐graft‐maleic anhydride (PE‐g‐MAH) as a compatibilizer and fumed silica as an additive. The resulting paper‐like composites were characterized by SEM and infrared spectroscopy. Other properties such as mechanical properties, thermal properties, whiteness, printability and adsorption performance were also tested in detail. It was found that remarkable enhancements in mechanical, thermal and printable properties of the paper‐like composites were obtained when nano‐SiO₂ loading was 2.5–3 wt%. Uniformly distributed holes that can endow good printability by providing space for ink or other functional molecules were observed by using SEM. Furthermore, the CIE whiteness value of the resulting composites can reach 91.6%–96.7% on adding nano‐SiO₂. Additionally, the paper‐like composites integrating nano‐SiO₂ and PE‐g‐MAH exhibited good solid ink affinity and high water or oil adsorption capacity. Thus, according to this research, high‐performance printable paper‐like composites used as major components of multifunctional papers can be prepared based on plastic flexible film wastes. © 2019 Society of Chemical Industry     

橡塑密封技术发展现状与趋势

阐述了近年来我国橡塑密封行业的发展情况及在各行业的应用,综述了橡塑密封结构设计、橡塑密封材料、检验检测和制造工艺的发展现状,分析了国内橡塑密封行业和技术与国外发达国家先进密封技术发展存在的差距和不足,提出了橡塑密封技术的发展方向,并就未来我国橡塑密封行业的发展提出了建议。     

Damage evolution around white etching layer during uniaxial loading

Rolling contact fatigue cracks and thermally induced defects are common problems in the railway industry especially as demands for increasing loads, speeds, and safety continue to rise. Often, the two types of defects are found together in the field, however, whether one causes the other to occur is not completely agreed upon. The effect of thermal damage, in the form of a martensite spot on pearlitic steel test bars, on the fatigue life in uniaxial low cycle fatigue experiments was investigated by the authors. However, the focus of the current work was to characterize the damage evolution from the low cycle fatigue (LCF) tests and correlate the crack initiation and propagation with the initial thermal damage. Residual stress measurements, digital image correlation, and X‐ray tomography were used to characterize the effects of the thermal damage before, during, and after fatigue testing, respectively. It was found that the thermal damage causes strain accumulation and crack initiation at the interface between the two materials. The strain evolution was visualized using digital image correlation (DIC), clearly showing the strain concentrations at the top and bottom of the white etching layers (WEL), where the residual stresses are also most tensile. X‐ray tomography confirmed the planar crack growth from the martensite spot.     

Microstructure,mechanical properties and bio-corrosion properties of Mg-HA bionanocomposites fabricated by a novel severe plastic deformation process

This research investigates the alterations in microstructure, mechanical properties, and corrosion behavior of binary magnesium-hydroxyapatite bionanocomposites with 2, 5, and 10 wt%HA. By mixing Mg and HA powders with different percentages of HA contents, a combined method of cyclic extrusion compression (CEC), equal channel angular pressing (ECAP) and conventional extrusion were employed to consolidate the mixture of powders. All composites were examined. The results indicate that the addition of hydroxyapatite to magnesium improves the mechanical properties, but these properties are deteriorated with the hydroxyapatite content of over 5 wt%. The corrosion behavior of the composites was examined by immersion test, mass loss and polarization tests in Hank’s solution. The results indicate that Mg-5HA exhibits the best corrosion resistance and the corrosion rate increases when the HA content rises to more than 5 wt%. In addition, the specimen produced through the proposed method in this work indicates better corrosion resistance in comparison with cast and extruded pure Mg.     

基于VOF模型的层叠器流动过程分析及流道结构优化

基于FLUENT软件的流体体积(VOF)模型研究了不同壁面滑移程度以及不同流道结构参数下4层等厚熔体通过层叠器倍增为8层熔体时,流道中熔体的分层情况变化。结果表明,壁面滑移程度的降低会促使熔体在上下壁面聚集,进而导致上下壁面处熔体层厚增加;汇流段与出口段间圆角半径、汇流段扩压角和平衡段长度这3个结构参数则只会影响熔体在左右壁面的聚集,进而影响各层熔体的尺寸精度,且其中扩压角的影响程度最大,平衡段长度次之,圆角半径的影响较小。