穿孔轧卡试样剖析

研究了穿孔变形区中毛管的几何尺寸和表面质量。     

连铸管坯裂纹在加热穿孔过程中的变化

研究了连铸管坯表面不同深度裂纹在加热穿孔过程中的变化。结果表明，在连铸管坯内部质量良好时，剥皮能显著改善穿孔毛管表面质量；加热穿孔可以消除或减少管坯表面的微裂纹；管坯表面较深的裂纹穿孔后将在毛管表面以外折的形式出现。     

Thermodynamic modeling of the Na–Al–Ti–H system and Ti dissolution in sodium alanates

Thermodynamic assessments were made to optimize thermodynamic models and parameter fits to selected experimental and first principles hypothetical predicted phase data within the Na–Al–Ti–H system. This enabled thermodynamic modeling of Ti solubility within the sodium alanates: NaAlH₄ and Na₃AlH₆, and the relative stability of Ti-bearing phases. The modeling provides insights into the role of Ti originating from Ti-based activating agents commonly referred to as ‘catalysts’ in promoting reversibility of the Na–Al–H dehydrogenation and rehydrogenation reactions under moderate temperature and pressure conditions relevant to H storage applications. Preliminary assessments were made to evaluate H solubility in bcc-Ti and hcp-Ti, and stability of the hydride δ-TiH₂. To model possible Ti dissolution in NaAlH₄ and α-Na₃AlH₆, sub-lattice models were applied. A repulsive interaction is predicted by first principles calculations when Ti is dissolved in NaAlH₄ or α-Na₃AlH₆, which becomes stronger with increasing temperature. Although Ti is virtually insoluble in NaAlH₄ or α-Na₃AlH₆, a small addition of TiCl₃ will induce a thermodynamic driving force for formation of TiH₂ and/or TiAl₃. The addition of pure Ti shows a weaker effect than TiCl₃ and leads to formation of TiH₂ only. Based on a combined interpretation of present thermodynamic modeling and prior experimental observations, the TiAl₃ and TiH₂ phases are ascribed to have a catalytic effect, not a thermodynamic destabilization effect, on the reversibility of the dehydrogenation/rehydrogenation reactions in the Na–Al–H system.     

论明槽挟沙水流的阻力

从挟沙水流的能量平衡原理出发 ,指出泥沙的运动从两个方面影响水流的阻力 :一是由于卡门常数的减小而引起的阻力减少 ,二是由于推移质泥沙的存在而引起的阻力增大。两者对阻力的作用正好相反 ,因而挟沙水流阻力比清水可能减小、增大及不变 ,取决于两者的对比程度。并从理论上给出了动平整床面挟沙水流阻力的计算公式 ,该公式的计算结果与实测资料吻合较好     

SLS翘曲变形计算与扫描方式优化

选择性激光烧结工艺(selective laser sintering,SLS)加工中所产生的翘曲变形严重影响了成型件的加工精度和SLS技术的应用与推广。本文在研究SLS成型误差的基础上,分析造成SLS成型件翘曲的主要原因与产生的机理,构建了一种新的翘曲变形的力学模型。并以此模型为基础,分析了现有SLS扫描方式存在的不足,提出一种新的间隔式激光光栅扫描方式。通过实验验证,该扫描方式可以有效地降低SLS成型件的翘曲变形,提高SLS成型件的加工精度,而且能大大提高加工速度,降低加工能耗。     

Seed Oils of Five Black Tartary Buckwheat Cultivars with Biochemical Characterization and Antioxidant Properties

Black tartary buckwheat oils (BTBOs) were extracted from five major industrial tartary buckwheat cultivars grown under similar agronomical activities and environmental conditions. These oils were characterized for the bioactive compounds containing fatty acids, β‐carotene, lutein, α‐, β‐, δ‐ and γ‐tocopherol, and for their antioxidant properties. The total tocopherol contents that were obtained ranged from 704.66 to 1156.19 mg/kg, with γ‐tocopherol (588.98–977.91 mg/kg) as the main component. The concentration of lutein ranged from 253.14 to 429.63 mg/kg, which was almost ten times higher than that of β‐carotenoid (46.71–69.2 mg/kg), indicating that black tartary buckwheat seed oils were a good source of lutein. The predominant fatty acids were unsaturated oleic acid (C18:1) (35.27–40.61 %) and linoleic acid (C18:2) (38.25–42.90 %). Excellent values of 2,2‐diphenyl‐1‐picrylhydrazyl radical (DPPH), diammonium salt (ABTS) radical scavenging activities were obtained and the highest oxygen radical absorbance capacity (ORAC) value of 13.89 mmol Trolox equiv/g oil was detected in the variety of Chuanqiao No. 1, which was clearly separated by principal component analysis (PCA) on the basis of the highest content of tocopherols and carotenoids. Moreover, the correlation analysis showed that tocopherols and carotenoids were the major contributors to the antioxidant activities of the BTBOs. This study demonstrates that lipophilic extraction in the tartary buckwheat seed contains many interesting bioactive compounds, which are beneficial for human health.     

物联网在食品加工环节的应用

食品安全已经成为世界性的话题,针对物联网在食品加工环节的应用展开研究,利用物联网的传感器对食品在加工环节的数据进行记录和监控,在服务器端把收集的数据存入数据库,并实现数据库的设计,为食品出厂的质量做出贡献。     

垂线平均含沙量两种表述方法之比较

表达沿垂线平均含沙量的方法通常有流量法与面积法两种，但在实际运用中常发生混淆。本文讨论了两种垂线平均含沙量之间的关系，指出面积平均含沙量需要大于流量平均含沙量。含沙量及流速分布越不均匀，两者差别就越大，当悬浮指标２≤０．３时两者相差不到１０％，最后还对两种垂线平均含沙量的应用作了初步搪塞。