Micro- and nano-scale deformation behavior of nylon 66-based binary and ternary nanocomposites

The primary aim of this paper is to provide an insight on the effect of the location of organoclay on the micro- and nano-scale deformation processes in melt-compounded nylon 66/organoclay/SEBS-g-MA ternary nanocomposites prepared by different blending sequences. In addition, the deformation processes of the ternary nanocomposites were compared to the binary nanocomposites (nylon 66/organoclay and nylon 66/SEBS-g-MA) and neat nylon 66. The incorporation of SEBS-g-MA particles toughened nylon 66 markedly; but the flexural modulus and strength were both reduced. Conversely, the use of organoclay increased the modulus but decreased the fracture toughness of nylon 66. Nylon 66/SEBS-g-MA/organoclay ternary nanocomposites exhibited balanced elastic stiffness and toughness. Stress-whitening studies of the fracture surfaces in terms of gray level were also performed and an attempt was made to correlate the optical reflectivity characteristics with fracture toughness. It was concluded that the capability of SEBS-g-MA particles to cavitate was decreased by the presence of organoclay in the SEBS-g-MA phase, resulting in reduced toughening efficiency. The best micro-structure for toughness and other mechanical properties is thus to maximize the amount of exfoliated organoclay in the nylon 66 matrix rather than to have it embedded in the finely dispersed SEBS-g-MA particles.     

基体拉伸法测试二氧化钛薄膜界面结合强度

利用热氧化法在工业纯钛表面形成氧化层,利用改进后的基体拉伸法研究了500和800℃加热1h所形成的氧化层和基体的结合强度,结果发现裂纹形貌与界面结合强度有关.500℃所形成的氧化层较薄,与基体的结合强度高,＞970MPa,裂纹方向与载荷轴向呈±45°;而800℃形成的氧化层较厚,与基体的结合强度差,＜495MPa,裂纹基本与载荷轴向垂直.     

New Application of Stainless Steel

Several rigid substrates such as stainless steel, titanium alloy, aluminum alloy, nickel foil, silicon, and sodium lime glass have been employed for manufacturing high quality TiO2 films by metal organic chemical vapor deposition （MOCVD）. The as-deposited TiO2 films have been characterized with SEM/EDX and XRD. The photocatalytic properties were investigated by decomposition of aqueous orange Ⅱ. UV VIS photospectrometer was employed to check the absorption characteristics and photocatalytic degradation activity. The results show that films synthesized on metal substrates display higher photoactivities than that on absolute substrates such as silicon and glass. It is found that solar light is an alternative to UV-light used for illumination during photodegradation of orange Ⅱ. TiO2 film on stainless steel substrate was regarded as the best one for photocatalysis.     

The growth of γ-LiAlO2 layer with a highly-preferred orientation on (0001) sapphire

Using vapor transport equilibration (VTE) technique we succeeded in the fabrication of single-phase γ-LiAlO2 layer on (0001) sapphire substrate. X-ray diffraction indicated that the as-fabricated layer was highly textured with [100] orientation at proper VTE treatment temperature range from 1050℃ to 1100℃. The main factors affecting the quality of the γ-LiAlO2 layer were investigated by SEM and transmission spectra. These results reveal the possibility of fabricating γ-LiAlO2 (100)// sapphire (0001) composite substrate for GaN-based epitaxial film by VTE.     

基板温度对SnO2:Sb薄膜结构和性能的影响

以单丁基三氯化锡(MBTC)和 SbCl3 为反应原料,采用常压化学气相沉积法(APCVD 法)在不同的基板温度下制备 Sb 掺杂 SnO2 薄膜,用 XRD、SEM表征了薄膜的结构和形貌,通过测量薄膜的方块电阻、载流子浓度、霍尔(Hall)系数、紫外可见光谱等性质,详细研究了基板温度对薄膜结构和光电性能的影响。实验表明 550℃以上制备的样品为多晶薄膜,并保持四方相金红石型结构;在 650℃下沉积的薄膜具有最低的方块电阻值,为 72Ω/□;在可见光区域薄膜透射率和反射率随着基板温度的提高均有所下降。     

透明导电氧化物薄膜及其制备方法

综述了透明导电氧化物(TCO)薄膜的特性、应用及制备技术的发展,重点讨论了磁控溅射、脉冲激光沉积、溶胶-凝胶、喷射热分解等制备技术和柔性衬底TCO薄膜的制备状况、进展及发展趋势,并指出改进TCO薄膜制备技术的努力方向应体现完善薄膜性能、降低反应温度、提高控制精度、降低制备成本和适应集成化等趋势,而制备方法的选择则应根据薄膜的性能要求和不同的应用目的而不同.     

透明导电薄膜在不同衬底上的性能对比研究

为了对比研究不同透明衬底上ZnO:Al(ZAO)薄膜的性能,采用直流反应溅射法制备薄膜,并对其作EDS、XRD和电学测试分析.结果表明:所制备的ZAO薄膜具有典型的ZnO晶体结构;沉积在玻璃基片上的ZAO薄膜,Al,O含量高于沉积在透明聚酯塑料基片上的,而Zn的含量则相反;在两种衬底上获得的ZAO薄膜电阻率分别为4.5×10-4Ω*cm和9.73×10-4Ω*cm,可见光透射率分别达到87.7%和81.5%.由此可见:用直流反应磁控溅射法在不同衬底上都能获得可见光透射率达到80%以上的ZAO薄膜;相比而言,在玻璃衬底上获得的ZAO薄膜电阻率低,而在透明聚酯塑料上沉积的ZAO薄膜透射性好.     

Plastic strain-controlled short crack growth and fatigue life

Constant plastic strain-controlled and constant stress-controlled tests were performed on smooth and lightly notched specimens machined from a massive forging of 42CrMo4 steel. Comparison of the fatigue life curves plotted as function of the plastic strain amplitude and stress amplitude shows a decisive role of plastic strain amplitude. Crack initiation and the kinetics of short crack growth were studied in constant plastic strain amplitude loading and the relation between the crack growth coefficient and plastic strain amplitude was established. This is equivalent to the Coffin–Manson law and shows that the Coffin–Manson law can be interpreted in terms of short crack growth.     

Analysis of the mechanical performance of a cardiovascular stent design based on micromechanical modelling

Stents are very commonly used in the treatment of coronary heart disease. They are permanent vascular support structures that offer a preferred alternative to bypass surgery in certain situations. The purpose of this work is to examine the mechanical behaviour of a stainless steel balloon expandable stent design using computational micromechanics in the context of the finite element method. Deployment and cardiac pulsing loading conditions are considered. Classical phenomenological plasticity theory (J₂ flow theory) and physically based crystal plasticity theory are used to describe the stent material behaviour. Parametric studies are carried out using both constitutive theories with a view to determining important stent deployment characteristics such as recoil and foreshortening. Comparisons of the results obtained using both theories illustrate differences, with the crystal plasticity theory models showing closer agreement to published performance data. The implications of this for stent design are discussed.