Correlation of Cooperatively Localized Rearrangement on the “Fluidized Domain” of Polymers to Their Nonexponentially Viscoelastic Behaviors at Double Aging Processes (I): A Set of Reduced Universal Equations on the Stress Relaxation Modulus and Creep Comp

基于α-和β-微区、微晶、交联和缠结链组网络结构和非线性粘弹性复相涨落模型,提出了双重(物理和力学)老化下不同尺寸和末端向量高分子链组的流动化微区内关联性局部化重排动力学新理论,它能把初级α-微区的降解作用和次级β-微区的再生效应对剪切速率、尺寸大小和温度依赖性有机结合起来．然后用统计力学和动力学结合法计算了三种不同类型高聚物在等温等压双重老化过程中多元链组的总构象改变自由能,证实了它起源于多元链组的尺寸大小、形状和体积的变化．推导出了它们单向拉伸下的本构方程、应力松弛模量和蠕变柔量表征式以及它们相对应的两组对比态普适方程．结果表明该两组对比态下应力松弛模量和蠕变柔量普适方程均具有同K-W-W伸展指数函数完全一致的形式．最终又建立了该两组对比态普适方程中三个分子参数同老化条件、温度和高聚物起始结构之间的相关性．     

One color contrast enhanced infrared and visible image fusion method

Color constancy (Toet and Franken, 2003 [2]; Toet, 2003 [7]) and color contrast (Scribner et al., 2000 [21]; Lee et al., 2005 [23]) are two important topics for color image fusion. The paper focuses on the low color contrast problem of linear fusion algorithms with color transfer method. Color transfer technology is popular in infrared (IR) and visible image fusion to give the fused image a natural day-time color appearance (Toet, 2003 [7]; Wang et al., 2007 [8]; Zheng and Essock, 2008 [9]). However, in the color transfer step, all three channels of the color space are processed with the same linear mapping without color enhancement, resulting in low color contrast between the target and the background (Wang et al., 2007 [8]). Based on the characteristics of the IR image, we introduce a ratio of local to global divergence of the IR image to improve the color contrast. The enhancement ratios for both hot and cold targets are larger than one, while it tends to one for the background. As a result, the proposed method pops out both hot and cold targets in color, where hot targets will appear intense red, and cold targets will appear cyan. Subjective results show visible color contrast enhancement effects. Target detection experiments through hue and saturation components of the fused image show an improvement in the hit rate for target detection, owing to larger color distance between the target and the background.     

A pigment (CuS) identified by micro‐Raman spectroscopy on a Chinese funerary lacquer ware of West Han Dynasty

A blue pigment was identified by micro‐Raman spectroscopy, X‐ray fluorescence spectroscopy (XRF), scanning electron microscopy (SEM)/energy dispersive X‐ray (EDX) and X‐ray diffraction (XRD). The test sample, a funerary lacquer tray, belongs to West Han Dynasty (206 BC–AD 8) of China and was decorated with faint blue patterns. The result from Raman spectroscopy showed that the faint blue is covellite (CuS) due to the presence of a characteristic peak at 474.5 cm⁻¹, which further was confirmed by XRF, SEM–EDX and XRD. This research indicated that CuS had been used as a blue pigment to decorate lacquer wares from the West Han Dynasty in China. Copyright © 2009 John Wiley & Sons, Ltd.     

Study on degradation of dimethoate solution in ultrasonic airlift loop reactor

In this work, the degradation of dimethoate solution in ultrasonic airlift loop reactor (UALR) assisted with advanced oxidation processes was studied. The effects of O₃ flow rate, ultrasonic intensity, pH value and reaction temperature on the degradation rate were investigated. UALR imposed a synergistic effect combining sonochemical merit with high O₃ transfer rate. Under the optimal operation conditions: ultrasonic irradiation time was 4 h, O₃ flow rate was 0.41 m³ h⁻¹, ultrasonic intensity was 4.64 W cm⁻², pH value was 10.0, reaction temperature was 25 °C, and initial concentration of dimethoate was 20 mg L⁻¹, degradation rate of dimethoate increased to 90.8%. The experimental results indicated that the method of UALR degradation of organic pollutants in the presence of gas could reduce reaction time and improve degradation rate. UALR was an advisable choice for treating organic waste waters and this device could be easily scale up. Thus this process has wide application prospect in industry.     

Phase and shape controlling of MnS nanocrystals in the solvothermal process

MnS nanocrystals with different phases and shapes were prepared through solvothermal synthesis. The products were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), UV–vis absorption and photoluminescence (PL) spectra. The solvent and reaction time played an important role in controlling the phase and shape of MnS nanocrystals. The possible mechanism of the shape evolution was investigated, which revealed that the crystal growth along the unique c axis of γ-MnS resulted in the rod-like MnS at the primary period, and the tetrahedral crystal seed of β-MnS with zincblende structure resulted in the interlinking of MnS rods, so the zigzag and three-branched and palm-like MnS appeared; with increasing reactive time the thermodynamically stable spherical α-MnS was favored through the Ostwald ripening process. The PL results showed that the intensity of γ-MnS was much weaker than that of α-MnS, and the trap state emissions of γ-MnS at 470 and 482 nm, respectively, disappeared, which might be ascribed to the difference of the shapes between the sphere and the rod or branch.     

反传热问题及其在深冷处理传热分析中的应用

深冷处理作为一种新的材料处理工艺,越来越受到人们的关注,目前深冷处理使材料性能提高的机理尤其是与升降温过程的耦合关系等还尚未完全清楚,需开展更深入的研究,而传热分析是此方面研究的基础。反传热分析方法是研究深冷处理传热问题的一种可行方法。较为详细地叙述了反传热问题的定义及其求解方法,介绍了反传热在深冷处理传热分析中的初步应用,并对深冷处理中应用反传热方法存在的问题进行了探讨。     

相位片湍流仿真装置中的激光漂移效应

 为了在内场中开展激光传输特性实验研究,设计了一种基于Kolmogorov谱的随机相位片的大气湍流物理仿真系统,并用该大气湍流模拟仿真系统对激光漂移效应进行了研究。采用光束质量分析仪对模拟传输的光斑图像进行采集和分析,通过比较实际漂移方差与理论漂移方差,验证了该湍流仿真系统模拟和评价光束在仿真传输中的性能。实验分析表明,基于湍流相位片物理仿真系统模拟的光束漂移方差与理论曲线基本一致。     

基于DPLS特征提取的LDA方法在玉米近红外光谱定性分析中的应用

提出了一种基于DPLS+LDA的玉米近红外光谱定性分析新方法.该方法在训练时,首先用包含30个玉米品种每个品种20个近红外光谱样本的训练集进行DPLS回归,确定最佳DPLS主成分数为28;然后对训练集光谱进行DPLS特征提取后再进行LDA分析,确定最佳LDA主成分数为26,并提取LDA特征.识别时,测试样本经过DPLS...     

亚波长金属线栅的设计、制备及偏振成像实验研究

针对红外偏振成像系统,运用等效介质理论,在氟化钙基底上设计了周期为200 nm,深度为100 nm的金属铝栅.模拟计算结果表明,设计的金属铝栅在中红外(3—5 μm)和远红外(8—12 μm)双波段范围内,以及±20°的视场范围内能够提供大于35dB的消光比.利用电子束曝光、反应离子束刻蚀、等离子去胶等工艺完成了金属铝栅的制作.将金属铝栅放在中波红外热像仪前,得到了目标轮廓清晰的偏振图像. 关键词： 亚波长衍射光栅 偏振成像 等效介质理论     

Theoretical calculations of thermophysical properties of single-wall carbon nanotube bundles

Carbon nanotube bundles are promising thermal interfacial materials due to their excellent thermal and mechanical characteristics.In this study,the phonon dispersion relations and density of states of the single-wall carbon nanotube bundles are calculated by using the force constant model.The calculation results show that the inter-tube interaction leads to a significant frequency raise of the low frequency modes.To verify the applied calculation method,the specific heat of a single single-wall carbon nanotube is calculated first based on the obtained phonon dispersion relations and the results coincide well with the experimental data.Moreover,the specific heat of the bundles is calculated and exhibits a slight reduction at low temperatures in comparison with that of the single tube.The thermal conductivity of the bundles at low temperatures is calculated by using the ballistic transport model.The calculation results indicate that the inter-tube interaction,i.e.van der Waals interaction,hinders heat transfer and cannot be neglected at extremely low temperatures.For(5,5) bundles,the relative difference of the thermal conductivity caused by ignoring inter-tube effect reaches the maximum value of 26% around 17 K,which indicates the significant inter-tube interaction effect on the thermal conductivity at low temperatures.