Tuning Parameter Selection Based on Blocked $$3\times 2$$3×2 Cross-Validation for High-Dimensional Linear Regression Model

Neural Processing Letters - In high-dimensional linear regression, selecting an appropriate tuning parameter is essential for the penalized linear models. From the perspective of the expected...     

钛酸酯偶联剂对磷石膏/HDPE性能的影响

采用3种钛酸酯偶联剂改性超细磷石膏(UPG),将改性后的UPG添加到高密度聚乙烯(HDPE)中,研究了钛酸酯偶联剂结构对UPG/HDPE复合材料力学性能的影响。结果表明,钛酸酯偶联剂改性的UPG接触角增大,吸油值降低,201-UPG改性效果最佳,接触角和吸油值分别为106.25°和0.23。与UPG/HDPE复合材料相比,101-UPG/HDPE、201-PG/HDPE、311-UPG/HDPE复合材料的拉伸性能、弯曲性能和冲击性能得到了一定的提高,在101-UPG/HDPE复合材料中的效果最佳,分别提高了42.41%、64.04%、174.65%。SEM测试表明,加入了钛酸酯改性剂的UPG在HDPE中的分散效果较佳;流变测试显示,101-UPG/HDPE复合材料的黏度比HDPE明显提高。     

Textural quality of sweet dumpling: effect of germination of waxy rice

Effects of germination on components and structural changes of rice flours and, in turn, rheological properties and textural attributes of sweet dumplings were investigated in this study. Germination decreased starch, protein and lipid content, while slightly increased free amino acids content. Starch granular surface corroded, crystalline structure disrupted, and short-range ordered structures and helical structures decreased with germination. Moreover, germination resulted in a decreased paste viscosity and gel intensity of flour and a reduction of hardness and adhesiveness of dumplings. According to the Pearson’s correlation analysis, flours components and starch structures were significantly correlated with flours rheological properties that determined textural attributes of sweet dumplings. The germination contributed to significant changes in flours components and starch structures, which suggested the pretreatment of germination of waxy rice could be a promising pathway to control textural properties of sweet dumplings.     

航向角BP神经网络自整定PID控制算法仿真

设计了基于BP神经网络的自整定PID控制算法,此控制算法不需要被控对象的数学模型,先由BP神经网络对被控对象进行辨识,给出PID控制所需要的3个参数,再由PID控制算法进行有效的控制,最后用MATLAB对某水下机器人的航向角模型进行了仿真验证。     

Electrodeposition of nano-nickel in deep eutectic solvents for hydrogen evolution reaction in alkaline solution

The electrodeposition of nano-Ni films on a Cu substrate from NiCl₂ precursors in choline chloride (ChCl)/urea or ethylene glycol (EG) based deep eutectic solvent (DES) was illustrated. Voltammetric study demonstrates that the electrodeposition of Ni(Ⅱ) in both ChCl/urea and ChCl/EG systems is a simple one-step reaction process, and the electrochemical process is a typical diffusion-controlled irreversible process. The obtained Ni films can be controlled to form nanostructures depending on the DES and the electrodeposition conditions. The nanostructured Ni films were investigated as electrodes for hydrogen evolution reaction (HER) in an alkaline medium. The enhanced catalytic activity toward the HER was confirmed, which is mainly attributed to the formation of needles morphology and the improved electrochemical surface area. The result reveals that the electrodeposition process may provide a promising strategy for the production of nano-Ni at low temperature for HER.     

Influences of vacancy defects on thermal conductivities of Ge thin films

The effects of vacancy defects on the thermal conductivity of Ge thin films were investigated by employing molecular dynamics(MD) simulations and theoretical analysis based on the Boltzmann equation.Both the MD and theoretical results show that the lattice thermal conductivity dramatically decreases with the increasing of vacancy concentration at 400 and 500 K.In addition,the dependence of vacancy concentration on the thermal conductivity of Ge thin films becomes less sensitive as the temperature increases.Theoretical results also confirm that the major part of the lattice thermal conductivity reduction is associated with the point-defect scattering and phonon-phonon scattering processes.     

低温快固化丙烯酸聚氨酯涂料的发展现状

从丙烯酸聚氨酯涂料的固化反应机理出发,系统分析了树脂、固化剂、催化剂和环境因素对丙烯酸聚氨酯涂层干燥速度的影响,重点讨论了羟基单体的种类和用量、亚胺结构的引入、玻璃化转变温度、相对分子质量及其分布、酸值及分子链结构等因素对树脂反应活性的影响。通过对目前低温快固化涂料研究中存在的问题的分析,指出精确控制树脂分子结构是实现修补涂料低温快固化的有效途径。     

复杂两相流中界面追踪方法——VOSET的性能分析

界面追踪方法-VOSET(coupled Volume-of-Fluid and Level Set method)结合了VOF和Level Set两种方法的优点,克服了这两种方法的缺点.VOSET方法采用VOF方法捕捉两相间的界面,保持了两相间的质量守恒,克服了Level Set方法质量不守恒的缺点;利用几何计算方法...     

Effects of vacancy structural defects on the thermal conductivity of silicon thin films

Vacancy structural defect effects on the lattice thermal conductivity of silicon thin films have been investigated with non-equilibrium molecular dynamics simulation.The lattice thermal conductivities decrease with increasing vacancy concentration at all temperatures from 300 to 700 K.Vacancy defects decrease the sample thermal conductivity,and the temperature dependence of thermal conductivity becomes less significant as the temperature increases.The molecular dynamics result is in good agreement with the theoretical analysis values obtained based on the Boltzmann equation.In addition,theoretical analysis indicates that the reduction in the lattice thermal conductivity with vacancy defects can be explained by the enhanced point-defect scattering due to lattice strain.