化学镀铜

化学镀铜是指不使用电解方法而从槽液中沉积渡铜。本文参考了国内外７０多篇文献，论述了化学镀铜的工艺、溶液控制、关键因素、机理的研究及其工程应用等。并对各工艺、机理的优劣进行了讨论。     

Different mechanisms controlling interannual phytoplankton variation in the South China Sea and the western North Pacific subtropical gyre: A satellite study

A time series of remotely-sensed chlorophyll a (chl a) in 1997–2010 was evaluated to determine mechanisms of phytoplankton variation in recent decade in the South China Sea (SCS) and the western North Pacific subtropical gyre (WNPSG). Satellite-derived sea surface temperature (SST) and aerosol optical thickness (AOT) were used as proxies for vertical nutrient supply and atmospheric aerosol, respectively. Chl a in the WNPSG was not significantly correlated with SST (r = 0.18, p > 0.05), but was with AOT (r = 0.31, p < 0.05), indicating the chl a was influenced by atmospheric deposition. Chl a in the SCS was negatively correlated with SST (r = −0.60, p < 0.05) and was positively with AOT (r = 0.20, p < 0.05). The correlation between AOT and chl a in the SCS does not reflect a major contribution from atmospheric deposition to chl a; instead, the relationship resulted from concurrence of the peaks of AOT and wind speed, which drive water mixing and nutrient supply. Consequently, chl a in the SCS would be regulated primarily by the nutrient supply from deep waters. Because SST was controlled by the ENSO teleconnection in the SCS, the chl a was coupled with ENSO events. The present study demonstrated that interannual phytoplankton variation could be controlled by different factors even in neighboring oligotrophic regions.     

真空等离子沉积中真空电弧的产生及触发电路的设计

在真空等离子沉积中，首先要触发真空电弧，由于等离子沉积本身所具有的复杂性，要成功地触发真空电弧必须考虑很多因素，如：阴极的材料、电极的结构、阴阳两电极之间的间隙、电极的表面状态、触发方式等。文中对影响触发电弧的因素以及在设计触发电路时需要的因素作了一定的分析，并在此基础上，提出了一个实用可靠的触发电路。     

Luminescent Nanocrystalline Silicon Carbide Thin Film Deposited by Helicon Wave Plasma Enhanced Chemical Vapour Deposition

Hydrogenated nanocrystalline silicon carbide （SIC） thin films were deposited on the single-crystal silicon substrate using the helicon wave plasma enhanced chemical vapor deposition （HW-PECVD） technique. The influences of magnetic field and hydrogen dilution ratio on the structures of SiC thin film were investigated with the atomic force microscopy （AFM）, the Fourier transform infrared absorption （FTIR） and the transmission electron microscopy （TEM）. The results indicate that the high plasma activity of the helicon wave mode proves to be a key factor to grow crystalline SiC thin films at a relative low substrate temperature. Also, the decrease in the grain sizes from the level of microcrystalline to that of nanocrystalline can be achieved by increasing the hydrogen dilution ratios. Transmission electron microscopy measurements reveal that the size of most nanocrystals in the film deposited under the higher hydrogen dilution ratios is smaller than the doubled Bohr radius of 3C-SiC （approximately 5.4 nm）, and the light emission measurements also show a strong blue photoluminescence at the room temperature, which is considered to be caused by the quantum confinement effect of small-sized SiC nanocrystals.     

描述颗粒沉积动力学演变过程的一种随机算法

为了解决普通Monte Carlo算法计算精度和计算代价无法协调的矛盾,发展了一种新的多重Monte Carlo(MMC)算法求解考虑多分散性颗粒沉积的通用动力学方程,该算法引入加权虚拟颗粒的概念,基于时间驱动MonteCarlo技术,模拟过程中保持虚拟颗粒数目和计算区域体积不变。首先详细介绍了考虑颗粒沉积的MMC算法,包括时间步长的设置、颗粒是否沉积的判断、沉积后果的处理等。然后选定三个存在理论分析解的特殊工况对MMC算法进行验证,数值模拟结果与相应的理论分析解符合很好,表明该算法具有较高的计算精度,同时该算法计算代价很小。     

Dy对EB-PVDβ-NiAl涂层高温瞬态氧化行为的影响(英文)

β-NiAl是一种有前景的应用于1150°C以上的抗氧化涂层材料。本文利用电子束物理气相沉积(EB-PVD)方法制备了0~0.5at%Dy含量的β-NiAl涂层,研究了涂层的瞬态氧化行为。1200°C时,在0.05at%Dy掺杂的涂层中只观察到了稳态α-Al2O3相,而在0.5at%Dy掺杂的涂层中,1h氧化过程中,发生了θ-Al2O3到α-Al2O3的相变。1100°C时,在最初的15min所有涂层均发生了θ-α相变。0.05at%Dy掺杂的涂层在45min的时候相变已经完成,这比0.5at%Dy掺杂涂层要早得多。过量Dy的掺杂能够延缓θ-α相变。未掺杂和过量掺杂涂层在20h氧化之后仍存在针状相θ-Al2O3,而0.05at%Dy掺杂的涂层中则为经典的颗粒状α-Al2O3形貌。     

沉积温度对碳化硅基体及其复合材料的影响

研究了沉积温度对化学气相渗透ＳｉＣ基体微观结构２及其纤维增强复合材料性能的影响。９５０℃沉积碳化硅为非晶态；１０００℃以上沉积出的碳化硅为结晶态，１０５０℃沉积碳化硅晶体取向为主：１２５０℃沉积碳化硅晶体取向为主。沉积温度升高，沉积深度和均匀性降低。     

高温氧化对EB-PVD热障涂层内部应力场分布影响的数值模拟

针对电子束物理气相沉积(EB-PVD)热障涂层(TBCs)复杂结构的特点,选用Walker黏塑性本构模型实现对其高温力学行为的准确描述.选择具有叶片曲率特征的圆管试样,并借鉴实际发动机载荷特征进行数值分析.重点考虑EB-PVD热障涂层界面的形状以及热生长氧化层(TGO)厚度变化对应力场的影响.计算结果表明,直线型界面对EB-PVD热障涂层结构的应力场改变不大,而余弦界面对EB-PVD热障涂层的应力场改变的幅度可达2倍之多;热生长氧化层的出现导致陶瓷层界面处的应力绝对值增加;无论是循环至最高温度1 050℃还是冷却到100℃时,界面波谷始终受径向压应力,此处不易形成损伤,而波峰处的应力比较大,且其应力状态是损伤容易形成的部位,可以认为是陶瓷层失效与破坏的危险点.     

二维硼材料的理论和实验研究进展

硼与其近邻元素碳一样形成sp~2杂化,易形成复杂的多面体结构。硼烯是硼元素的二维同素异形体,研究者们对其结构和物化特性一直有着浓厚的研究兴趣。由于其制备技术难以突破,长期以来该领域的研究只停留在理论探索上。最近,在铜、银基底上生长出了单层硼烯薄膜,并对其原子结构和光电特性进行了深入研究,这些实验研究为未来研制基于硼烯的高性能电子器件奠定了良好基础。本文首先介绍硼烯的理论研究进展,然后着重介绍二维硼实验制备及其光电性能表征等研究,并对当前国际上二维硼薄膜实验研究进展进行了总结和展望。     

脉冲能量沉积对超声速射流/激波相互作用掺混的控制研究

为探究超声速射流掺混增强的有效控制方法,基于二维非稳态雷诺平均Navier-Stokes方程,研究了脉冲能量沉积对超声速射流与斜激波相互作用后增强掺混的控制机理和规律。宽度为5 mm的低密度平面射流同向完全膨胀射入马赫数为2.5的主流中,并与20°压缩斜面所产生的斜激波相互作用。在流场中引入脉冲能量沉积对射流掺混进行控制,并考虑射流马赫数、射流长度、能量沉积位置及激励频率对掺混效果的影响。对比激励流场与基础流场,结果表明:脉冲能量沉积的加入诱导射流形成大尺度涡结构,显著提高射流的掺混效果;能量沉积位置对于不同马赫数射流的掺混增强具有不同的控制效果;激励前后射流宽度的对比表明,脉冲能量沉积的无量纲激励频率在0.22附近时,可使得射流的掺混效果最佳。