旋风除尘器的气固两相流的数值模拟与分析

采用Reynold应力方程湍流模型(RSM)模拟了旋风除尘器内的流场,并得到流场内Reynold应力具有各向异性的特征.采用离散相模型(DPM),模拟了固体颗粒运动轨迹,并对固体颗粒的分离效率进行了分析.     

基于RGB三通道相位调制彩色编码

本文提出一种具有初始相位信息的RGB彩色编码方法。此法充分利用了彩色图像R、G、B三个分量携带的信息,即对三个分量分别进行相移为-120°、0°、120°的正弦调制,从而代替传统三幅相移法中的三幅相移图。首先投射一幅彩色RGB正弦条纹来调制被测物体的三维信息,摄像机拍得物体表面的变形条纹图,用数字方法把彩色变形条纹分为三幅灰度图像,然后应用三步相移方法获取截断相位,根据编码特征进行解码来指导截断相位的展开,获得展开相位,进而恢复出物体的三维面形。该方法编码稳定,解码方法可靠,只需要拍摄一幅图,就可以较好地重建空间分离物体的三维面形。通过实验证明了该方法的正确性。     

网络数据包到达速率的混沌特性分析及其短期预测

本文利用关联维法分析了以太网数据包到达速率数据的混沌特性，在此基础上，结合相空间重构技术，利用混沌时间序列的局域一阶预测法对其进行了预测，预测结果表明该混沌预测方法能够对网络数据包到达速率取得很好的预测效果．这为进一步研究网络流量提供了基础，也为网络数据包到达速率具有混沌特性提供了新的依据．     

Na0.54Bi0.46Ti0.96Al0.04O2.94氧离子导体制备与性能研究

采用传统的固相反应法合成Na0.54Bi0.46Ti0.96Al0.04O2.94氧离子导体,借助于交流阻抗谱和介电弛豫谱分别研究了钠和铝的双掺杂对Na0.5Bi0.5TiO3材料电学性能及氧离子扩散的影响。在400℃时,Na0.54Bi0.46Ti0.96Al0.04O2.94材料的晶粒电导率可以达到1.51×10-3 S/cm,是Na0.5Bi0.5TiO3材料电导率的5.5倍。在Na0.54Bi0.46Ti0.96Al0.04O2.94材料中观察到一个与氧离子弛豫相关的介电弛豫峰,弛豫参数为E= 0.80 eV和t0= 6.12×10-13 s,氧离子在Na0.54Bi0.46Ti0.96Al0.04O2.94材料中主要通过Na-Bi-Ti的路径进行扩散迁移的。结合结构参数容忍因子及自由体积的分析,钠和铝的双掺杂改善了氧离子在Na0.5Bi0.5TiO3材料中的扩散通道,但是铝的引入一定程度上提高了氧空位扩散的能量壁垒。     

Tuning microstructure,transformation behavior,mechanical/functional properties of Ti-V-Al shape memory alloy by doping quaternary rare earth Y

The microstructure features, martensitic transformation behavior and mechanical/functional properties of Ti–V–Al alloy were tailored by changing rare element Y content in the present investigation. The results showed that Y doping resulted in the grain refinement and formation of Y-rich phase mainly distributing along grain boundary in Ti–V–Al alloys. The martensitic transformation temperatures of Ti–V–Al alloys slightly increased due to the variation of matrix composition induced by the presenc...     

Electrode/electrolyte interface and interface reactions of solid oxide cells:Recent development and advances

High temperature solid oxide cells(SOCs) consisted of solid oxide fuel cells(SOFCs) and solid oxide electrolysis cells(SOECs) are considered one of the most environmentally friendly and efficient energy conversion technology to store renewal energy from sun and wind in hydrogen and generate electricity from the fuels such as hydrogen and natural gas with high efficiency and very low greenhouse gas emission. Over the last few decades, the development of SOC technologies in particularly SOFCs has ...     

Phase evolution process and hydrogen storage performances of V72Ti18Cr10 alloy prepared by Co-precipitation-reduction method

The V₇₂Ti₁₈Cr₁₀ alloy was prepared by a co-precipitation-reduction method in order to consume less energy during whole-life alloy manufacturing, and the phase evolution process in hydrogenation/dehydrogenation process was investigated. The structure refinement analysis of the alloy contented with 1 ?wt% hydrogen after hydrogenation shows that BCC phase, BCC-hydride phase and FCC phase coexisted, but little BCT phase was found. It indicates that the phase evolution process during hydrogenation was BCC→ BCC-hydride→ FCC, nevertheless the formation of BCT phase was restrained. The limited particle sizes of the alloy in the range of 0.1–5 ?μm and fewer defects than the normal alloy ingot contributed to the suppression of BCT formation. The annealed alloy, which had similar particle sizes with the unannealed alloy, has less unevenness of the compositions than the unannealed alloy, and the annealed alloy showed flatter plateau in the hydrogenation PCT (pressure-composition-temperature) curves. However, the BCT phase in the annealed alloy appeared in its dehydrogenation process owing to the produced defects during the following dehydrogenation and the hydrogenation process. The alloy with the limited particle sizes even in the range from 0.1 ?μm to 5 ?μm could not prevent the generation of BCT phase in the dehydrogenation process.     

Stability of thermal cycling and high temperature mechanical properties for Ti–V–Al–B lightweight shape memory alloy

The microstructure of the Ti–V–Al shape memory alloy with refined grain and in-situ TiB phase was modified by doping minor Boron (B), which contributes to the superior mechanical performances and strain recovery characteristics. Compared with other quaternary Ti–V–Al-X alloys, the Ti–V–Al–B alloy showed the largest ultimate tensile stress due to the solution strengthening, grain refinement and precipitation strengthening of in-situ TiB phase. Moreover, the Ti–V–Al alloy added 0.1 ?at.%B possessed the maximum yield stress of 701 ?MPa and the largest tensile fracture strain of 27.6% at the temperature of 150 ?°C. Meanwhile, the excellent strain recovery characteristics with fully recoverable strain of 4% could be obtained due to B addition. Besides, B addition suppressed the precipitation of ω phase during thermal cycling and further improved the thermal cycling stability of the Ti–V–Al alloy.     

In-situ study on γ phase transformation behaviour of γ-TiAl alloys at different cooling rates

γ-TiAl-based alloys are promising lightweight high-temperature structural materials, and the transformation from the α parent phase to γ lamellae during the cooling process has a great influence on the microstructures and mechanical properties of TiAl alloys. In this paper, an in-situ observation technique, high-temperature laser scanning confocal microscopy (HTLSCM), was utilized to investigate the continuous cooling transition (CCT) from the α phase in three compositions. The nucleation and growth behaviors of γ lamellae were studied at several moderate cooling rates. In addition, the processes of helium gas quenching for three alloys were investigated, and the massive transformation was observed in Ti–49Al. CCT diagraphs were concluded for three alloys. The Vickers hardness of TiAl alloys subjected to different cooling rates was tested, and it was found that the hardness of alloys was enhanced with increasing cooling rate due to the refinement of lamellar spacing.     

Effective antibacterial and phase change PEG/Cu2O@A-HNTs composites for melt-spun difunctional PA6 fiber

Serving as the only defensive line between pathogens and human body, personal protective equipment (PPE) is increasingly attractive among researchers because of their strong antibacterial and temperature control abilities. However, efficient antibacterial properties and regenerative thermal control simultaneously remain unexplored in PPE. Here, one-dimensional halloysite nanotubes (HNTs) modified by acid etch method, are used to synthesis a multifunctional material of PEG/Cu₂O@A-HNTs via in-situ reduction and physical adsorption which serves the above two purposes. PEG/Cu₂O@A-HNTs showed rapid bacterial inactivation and achieved 96.3% bacteriostatic rate against E. coli in only 20 ?min. Meanwhile a broad and complete inactivation spectrum included both E. coli and S. aureus following a series of antibacterial mechanisms. Moreover, adsorption of 70 ?wt% PEG by acid etch HNTs is attributed to the nearly 3 times increased specific surface area compared with native HNTs. This enabled PEG/Cu₂O@A-HNTs to attain a phase change enthalpy of 108.4 ?J/g. In addition, using PEG/Cu₂O@A-HNTs as additives, antibacterial and phase change fiber (APCF) were melt-spun. Their efficiency factor against E. coli and S. aureus was above 99.99%, and retained a temperature control ability for 180s and 272s compared with PA6 fiber in hot and frigid environments respectively.