Effects of B2O3 on Crystallization,Structure, and Heat Transfer of CaO-Al2O3-Based Mold Fluxes

Metallurgical and Materials Transactions B - The reaction between traditional CaO-SiO2-based mold fluxes and high-Al steel inevitably changes flux composition, and, consequently, flux properties....     

"一带一路"沿线中国境外产业园区规划实践研究

在"一带一路"倡议深入实施的背景下,中国境外产业园区得到沿线国家的普遍认同,正在成为支撑"一带一路"倡议落地开花的重要手段,这也为中国开发区规划技术"走出去"提供了机会和提出了需求.本文系统梳理了相关领域的学术研究状况,在分析相关法定规划体系架构基础上,结合实地调研,对中国境外产业园区的规划实践进行了系统梳理和分析,对既有境外园区规划类型与内容、规划技术标准、规划编制组织和管理体系等进行了总结,结合园区就业者对规划建设的评价和需求等,分析了境外园区规划建设存在的主要问题,提出了境外产业园区规划体系创新的策略性建议,为构建全球化的境外产业园区规划技术体系提供支撑,也为中国城乡规划技术"走出去"探路.     

Citation recommendation based on citation tendency

Scientometrics - Due to the development of academic, more and more attentions are paid to citation recommendation. To solve the citation recommendation problem, researchers begin to focus on the...     

一种基于机器视觉的表面缺陷快速检测方法

实际生产过程中,产品表面会不同程度地留下污渍和印记,这对基于机器视觉的表面缺陷识别带来严重干扰.基于图案统计分析的识别方法速度虽快,但抗干扰能力弱,出现较高的误判率.基于深度学习的人工智能识别方法计算量巨大,速度慢,难以满足生产实际的高速要求.因此介绍一种改进SIFT算法,并给出了相关参数的设置方法和经验公式,通过实际表面缺陷的检测,对比验证了SIFT算法较强的鲁棒性和抗干扰能力,以及相关参数设置方法的正确性和可行性.实验数据表明,SIFT算法在凹陷类和斑点类缺陷的检出率上具有明显优越性,在裂纹类的误检率上也具有较大优势.特别是在有噪声图像干扰情况下,检出率比神经网络提升了20％,误检率降低了3％.     

Influence of geosynthetic reinforcement on the stability of an embankment with rigid columns embedded in an inclined underlying stratum

Incompressible dipping substrata are commonly encountered in engineering practice. Compared to horizontal underlying strata, the inclined underlying stratum increase the risk of collapse of embankments reinforced with columns because it weakens the restraint of the column base. The objective of this study is to investigate the effectiveness of geosynthetics on improving the embankment stability when the underlying stratum is inclined. The influence of geosynthetic tensile stiffness on the ultimate surcharge and failure mechanism is studied. A deep-seated failure with column tilting occurs when the geosynthetic tensile stiffness is low, whereas a lateral sliding occurs when the geosynthetic tensile stiffness is high. To illustrate the contribution of geosynthetics, the distribution of the lateral pressures acting on the columns is analyzed.     

高职生物化工专业"微生物学实验"的思政教学探索

为了响应"全员育人、全程育人、全方位育人"三全育人的重要举措,以及体现专业课程在立德树人方面的重要作用和对生物化工专业的认同,文中旨将专业知识与社会主义核心价值观有机的融合,润物细无声的对学生进行思政教育,积极探索微生物学实验中能够与思政元素相融合的切入点,一方面激发了学生的学习兴趣和自学潜能,提升了课堂教学效果和效率,另一方面达成了生物化工行业对高质量人才的需求.     

Spreading and Curing Behaviors of a Thermosetting Droplet-Silicone on a Heated Surface

Thermosetting materials are widely used as encapsulation in the electrical packaging to protect the core electronic components from external force, moisture, dust, and other factors. However, the spreading and curing behaviors of such kind of fluid on a heated surface have been rarely explored. In this study, we experimentally and numerically investigated the spreading and curing behaviors of the silicone(OE6550 A/B, which is widely used in the light-emitting diode packaging) droplet with diameter of ～2.2 mm on a heated surface with temperature ranging from 25 ℃ to 250 ℃. For the experiments, we established a setup with high-speed camera and heating unit to capture the fast spreading process of the silicone droplet on the heated surface. For the numerical simulation, we built a viscosity model of the silicone by using the Kiuna's model and combined the viscosity model with the Volume of Fluid(VOF) model by the User Defined Function(UDF) method. The results show that the surface temperature significantly affected the spreading behaviors of the silicone droplet since it determines the temperature and viscosity distribution inside the droplet. For surface temperature varied from 25 ℃ to 250 ℃, the final contact radius changed from ～2.95 mm to ～1.78 mm and the total spreading time changed from ～511 s to ～0.15 s. By further analyzing the viscosity evolution of the droplet, we found that the decreasing of the total spreading time was caused by the decrease of the viscosity under high surface temperature at initial spreading stage, while the reduction of the final contact radius was caused by the curing of the precursor film. This study supplies a strategy to tuning the spreading and curing behavior of silicone by imposing high surface temperature, which is of great importance to the electronic packaging.     

Chromium evaporation and oxidation characteristics of alumina-forming austenitic stainless steels for balance of plant applications in solid oxide fuel cells

The chromium (Cr) evaporation behavior of several different types of iron (Fe)-based AFA alloys and benchmark Cr₂O₃-forming Fe-based 310 and Ni-based 625 alloys was investigated for 500 h exposures at 800 °C to 900 °C in air with 10% H₂O. The Cr evaporation rates from alumina-forming austenitic (AFA) alloys were ~5 to 35 times lower than that of the Cr₂O₃-forming alloys depending on alloy and temperature. The Cr evaporation behavior was correlated with extensive characterization of the chemistry and microstructure of the oxide scales, which also revealed a degree of quartz tube Si contamination during the test. Long-term oxidation kinetics were also assessed at 800 to 1000 °C for up to 10,000 h in air with 10% H₂O to provide further guidance for SOFC BOP component alloy selection.     

Evaluation of bismuth doped La2-xBixNiO4+δ (x = 0, 0.02 and 0.04) as cathode materials for solid oxide fuel cells

Bismuth doped La_2-xBi_xNiO_4+δ (x = 0, 0.02 and 0.04) oxides are investigated as SOFC cathodes. The effects of Bi doping on the phase structure, thermal expansion, electrical conduction behavior as well as electrochemical performance are studied. All the samples exist as a tetragonal Ruddlesden-Popper structure. Bi-doped LBNO-0.02 and LBNO-0.04 have good chemical and thermal compatibility with LSGM electrolyte. The average TEC over 20–900°С was 13.4 × 10^?6 and 14.2 × 10^?6 K^?1 for LBNO-0.02 and LBNO-0.04, respectively. The electrical conductivity was decreasing with the rise of Bi doping content. EIS measurement indicates Bi doping can decrease the ASR values. At 750 °C, the obtained ASR for LBNO-0.04 is 0.18 Ωcm², which is 56% lower than that of the sample without Bi doping, suggesting Bi doping is beneficial to the electrochemical catalytic activity of LBNO cathodes.