Structure analysis and property improvements of the computer-simulated fullerene-based ultralow-k dielectrics

We have recently proposed new ultralow-k dielectric materials using a theoretical approach called molecular design. This approach requires the application of complementary theoretical methods to describe the complex problems. The methods include classical, continuum theoretical, and quantum-chemical approximations. The advantage of the present approach is that various possible candidates for ultralow-k dielectrics can be tested theoretically without performing expensive and time-consuming experiments. In this study, we analyze the way to connect linker molecules to the node molecules, in order to improve mechanical and dielectric properties of generated ultralow-k structures. Two different types of bonding linker molecules to the cage C₆₀ molecule with the >CC< and >CCH₂CH₂C< linker molecules are possible. It is shown that at the present improvement step it is possible to get property combinations with dielectric constant of k = 2.2 and bulk modulus of B = 33 GPa for the simple cubic topology.     

Finite Element Analysis of Ceramic Coatings under Spherical Indentation with Metallic Interlayer： Part Ⅰ Uncracked Coatings

Spherical indentation of ceramic coatings with metallic interlayer was performed by means of axisymmetric finite element analysis （FEA）. Two typical ceramic coatings with relatively high and low elastic modulus deposited on aluminum alloy and carbon steel were considered. Various combinations of indenter radius-coating thickness ratios and interlayer thickness-coating thickness ratios were used in the modeling. The effects of the interlayer, the coating and the substrate on the indentation behavior, such as the radial stress distribution along the coating surface as well as the coating interface, and the plastic deformation zone evolution in the substrate were investigated in connection with the above mentioned ratios. The coating cracking dominant modes were also discussed within the context of the peak tensile stresses on the coating surface and on the coating interface.     

粘土的化学处理及工业应用研究

本文阐述粘土矿物的化学处理原理和方法，介绍我所有关粘土活化，表面修饰改性，层间插入及其工业应用产品开发研究的部分情况。     

用SEM研究表面处理对炭纤维增强复合材料剪切断裂的影响

利用扫描电子显微镜（ＳＥＭ）,对炭纤维表面处理前后,炭纤维增强复合材料（ＣＦＲＰ）的剪切断面的观察,并分析了不同表面处理方法对ＣＦＲＰ的界面性质的影响。结果表明,经气液双效法处理后,ＣＦＲＰ得到高的层间剪切强度（ＩＬＳＳ）,同时表现出二剪和三剪的断裂模式。     

Preparation of SiO2/Si3N4 ceramics with step gradient porosity and heavy metal ion adsorption

Microporous ceramics with slag gradient distribution were prepared by interlayer bonding methods, using silicon dioxide and silicon nitride as the main raw materials. The material performances of gradient ceramics and uniform ceramics were discussed, and the adsorption effects of Cd (Ⅱ), Pb (Ⅱ) between them were compared. The experimental results show a flexural strength of gradient ceramics of 10.67 MPa, bonding strength of the bonding layer of 15.28 MPa, and only a 0.89% difference in the line shrinkage of the gradient layer of different slag contents, indicating that it is feasible to utilize interlayer bonding methods to prepare gradient ceramics. The maximum adsorption quantity of Cd (II), Pb (II) of gradient ceramics can reach 3.48 mg/g and 4.40 mg/g, respectively. For an average slag content of 17.5 wt%, gradient ceramics exhibited high permeability flux equivalent to ceramic with 25 wt% slag content and heavy metal adsorption amount equivalent to ceramic with 20 wt% slag content. Overall, the gradient ceramics prepared by interlayer bonding method can effectively improve the removal efficiency of adsorbent and the overall filtration efficiency.     

纳米镍粉在钛合金-不锈钢扩散焊接中的应用

采用恒温恒压扩散焊、相变超塑性扩散焊、冲击加压扩散焊对直接对焊和加纳米镍粉中间层的钛合金-不锈钢焊接接头进行了研究。测试了接头强度,并进行了断口形貌观察和组织分析,结果表明：3种试验方法中,恒温恒压扩散焊所得接头强度较小,而冲击加压扩散焊所得接头强度较高;直接扩散焊时,接头上两种基体材料之间的互扩散程度很大程度上影响了钛合金-不锈钢接头的强度;采用纳米镍粉作中间层能形成强度较高的接头,达到了213MPa、但纳米镍粉的致密度不够高,接头的强度在很大程度上受到了限制。     

Statistical investigation of two different interlayer shear test methods

The performance of multi-layered pavement systems strongly depends on interlayer bonding. In order to evaluate this parameter, some countries have developed their own test method. However, different devices generally provide different results due to the test conditions. In this article, the statistical investigation of two interlayer shear test methods is shown considering different asphalt materials and different specimen preparation techniques. Both test methods provided comparable results showing the same ranking in interlayer shear stress for different test conditions and the same level of precision in terms of scatter of the results. Moreover, the repeatability limit was found to be dependent on the test method, the pavement material and the compaction technique. It is worth noting that this extensive experimental investigation paves the way for the incoming European Standardization process involving the two shear test methods.     

Solvent extraction induced nano-porous zinc oxide as an electron transport layer for inverted polymer solar cells

A facile and cost-effective method is demonstrated to prepare a nano-porous rugged zinc oxide (ZnO) film without complicated processes and strict condition. A sol–gel derived ZnO is simply coated onto the substrate and subsequently removed the unreacted precursor and residual matters by solvent extraction. Thus, the precursor and residuals provide the vacancy to form a highly rugged surface. Compared with the flat ZnO film, the rugged ZnO is not only performs better purity than the flat film, but also increases the interfacial contact between the ZnO and bulk-heterojunction layer. By using the rugged ZnO as an electron transport layer, an enhancement of 20% in photocurrent generation could be achieved in an inverted poly(3-hexylthiophene):[6,6]-phenyl C₆₁ butyric acid methyl ester solar cell together with highly air stability.     

The effect of small-molecule electron transporting materials on the performance of polymer solar cells

It has been studied that the effect of different electron transporting materials, including 2-(4-biphenyl)-5-(4-tert-butylphenyl)1,3,4-oxidiazole (PBD), tris-8-hydroxy-quinolinato aluminum and Bis[2-(2-benzothiazoly)phenolato]zinc(II) on the properties of solar cells based on poly(3-hexylthiophene) and [6,6]-phenyl-C₆₁-buytyric acid methyl ester composites. The results suggest that the insertion of electron transporting layers (ETL) can improve the open circuit voltage (Voc) and power conversion efficiency (PCE) of the polymer solar cells. And the effect of thickness of the three ETL has also been investigated. The cell with a PBD layer exhibits an enhanced Voc by 0.16 V and the highest PCE, which is 1.6 times that of the cell without ETL. The improved performance is due to the increased built-in potential in the interface between the active layer and Al electrode.     

Pentacene nanostructural interlayer for the efficiency improvement of polymer solar cells

In poly(3-hexylthiophene) mixed with phenyl C61-butyric acid methyl ester heterojunction polymer solar cells, organic small molecular pentacene was introduced as the interfacial layer between PEDOT:PSS coated ITO substrates and polymer layer. It is found that the short circuit current density and power conversion efficiency were distinctly improved due to the introduction of the nanostructural pentacene interlayer. The nearly 100% power conversion efficiency improvement was obtained on the cells with a 4 nm pentacene interlayer, which benefits from the increased short circuit current from 2.34 mA/cm² to 5.76 mA/cm². The morphology of different thicknesses of pentacene thin films was observed by atomic force microscopy. The effect of pentacene interlayer's thickness on the distribution of light in the active layer was simulated by using a transfer matrix mode.