Synthesis and adsorption properties of gold nanoparticles within pores of surface‐functional porous polymer microspheres

Mesoporous polymer microspheres with gold (Au) nanoparticles inside their pores were prepared considering their surface functionality and porosity. The Au/polymer composite microspheres prepared were characterized by transmission electron microscope (TEM), X‐ray diffraction (XRD), and Brunauer–Emmett–Teller (BET) techniques. The results showed that the adsorption of Au nanoparticles could be increased by imparting the pore structure and surface‐functional groups into the supporting polymer microspheres (in this study, poly (ethylene glycol dimethacrylate‐co‐acrylonitrile) and poly (EGDMA‐co‐AN) system). Above all, from this study, it was established that the porosity of the polymer microspheres is the most important factor that determines the distribution and adsorption amount of face‐centered cubic (fcc) Au nanoparticles in the final products. Our study showed that the continuous adsorption of Au nanoparticles with the aid of the large surface area and surface interaction sites formed more favorably the Au/polymer composite microspheres. The BET measurements of Au/poly(EGDMA‐co‐AN) composite microspheres reveals that the adsorption of Au nanoparticles into the pores kept the pore structure intact and made it more porous. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5627–5635, 2004     

The effects of O deficiency on the electronic structure of rutile TiO2

Ab initio density functional calculations (plane wave GGA, CASTEP) were performed to determine the effect of O deficiency on the electronic structure of rutile, TiO₂. O deficiency was introduced through either the removal of O or the insertion of interstitial Ti atoms. At physically realistic concentrations of O vacancies in the rutile lattice (i.e. 25% and less) O deficiency results in the population of the bottom of the conduction band, the location of the Ti 3d orbitals in the pure structure, increasingly with increasing vacancy concentration. We propose that this could be confused with the formation and population of gap states especially where O vacancies occur in isolated positions in the lattice. In contrast, Ti interstitials introduce a defect state into the energy gap, without an overall reduction in the size of the energy gap. O vacancies result in a spin polarized solution, whereas Ti interstitials do not.     

Photoemission study of the modification of the electronic structure of transition-metal overlayers on TiO2 surfaces II. Cr on TiO2(0 0 1)

The electronic states of the Cr overlayers on TiO₂(0 0 1) surfaces have been investigated using angle-resolved and resonant photoemission spectroscopy with synchrotron radiation. At lower coverages, Cr deposition on TiO₂(0 0 1) creates two well separated in-gap emissions due to the formation of surface Ti³⁺ (3d¹) ions and Cr³⁺ (3d³) ions. At higher coverages, the in-gap emission is developed into the 2-peak-structure emission of Cr 3d character. The corresponding state is considered to be of metallic nature from the viewpoint of the high ability of oxygen adsorption, but has no Fermi edge, indicating a possibility of forming small Cr clusters on TiO₂(0 0 1) at this stage.     

Bohr-Mottelson转动谱公式参数之间的新关系式

在利用Harris两参数公式研究Bohr-Mottelson转动谱公式参数之间的关系的基础上,改用Harris三参数公式,并由此提出了Bohr-Mottelson转动谱公式参数之间的新关系式,进而用I(I+1)四参数展开式计算了A～60,80,130,140,150,190区超形变偶偶核的基带和锕系和稀土区正常形变核基带,讨论了参数之间的关系,发现新关系式与实验较好地符合.     

Crystallographic report: Bis(norfloxacin)dilead(II) tetranitrate, [Pb2(H‐Norf)2(ONO2)4]

The centrosymmetric binuclear structure of [Pb₂(H‐Norf)₂(ONO₂)₄]shows the geometry around each lead(II) atom to be distorted trigonal bipyramidal with Pb–O distances ranging from 2.357(3) to 2.769(4) Å. Copyright © 2003 John Wiley & Sons, Ltd.     

Photo-induced evolution of copper sheets from cluster molecules and its application to photolithographic copper patterning

UV photoexcitation of (t-butylethynyl copper)₂₄ cluster films induces segregation of the crystals into metallic and organic phases and leads to evolve the metallic sheets sandwiched by organic polymers. The growth of the metallic crystals in the plane of the photo-electromagnetic field is attributed due to plasmon-plasmon interaction among nanoparticles embedded in dielectric polymer matrices. The surface enhanced photochemical reaction of residual cluster molecules on the photon incident direction is expected to take an important role for joining the metal particles to produce a metallic sheet. We can apply this phenomenon for photolithographic copper pattern generation on a flexible base plate.     

Study of local lattice relaxation of substitutional impurities in silicon and germanium

Local lattice relaxation of substitutional donors in silicon investigated using self‐consistent multiple scattering Xα (MSXα) method within the framework of the standard muffin‐tin potential approximation is extended to substitutional donors in germanium and substitutional acceptors in both silicon and germanium. Incorporating the effect of lattice relaxation surrounding the impurity makes the model suitable for both shallow and deep levels. Chemical trends of some aspects of impurity states, such as local lattice relaxation and charge transfer, of the impurities both in silicon and germanium are inferred. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004     

First-principles study of indium on silicon (1 0 0)—the structure, defects and interdiffusion

The atomic structures of indium (In) on silicon (Si) (1 0 0)-(2 × 1) surface are investigated by the local density approximation using first-principles pseudopotentials. Total energy optimizations show that the energetically favored structure is the parallel ad-dimer model. The adsorption energy of In on ideal Si(1 0 0)-(1 × 1) surface is significantly higher than that on reconstructed Si(1 0 0)-(2 × 1) surface, suggesting that In adsorption does not break the Si-Si dimer bond of the substrate. When Si surface contains single dimer vacancy defects, In chain will be interrupted, leading to disconnected In nanowires. Displacive adsorption of In on Si(1 0 0) is also considered, and the calculation suggests that interdiffusion of In into Si substrate will not be favorable under equilibrium conditions.     

基片温度对坡莫合金薄膜结构和磁电阻的影响

用磁控溅射方法制备了系列坡莫合金Ni80Fe20薄膜。利用X射线衍射、扫描电子显微镜和原子力显徽镜分析了薄膜的结构、晶粒取向、薄膜厚度、截面结构和表面形态。用4点探测技术测量了薄膜的电阻和磁电阻。结果表明：随衬底温度的升高，晶粒明显长大。膜内的缺陷和应力显著减小，而且增强了薄膜晶粒的[111]择优取向。结果表明，薄膜电阻率显著减小，而磁电阻显著增大。     

POROSITY CALCULATION OFMIXTURES OF FIBROUS PARTICLES

The initial forming of fiber blend to high green density, i.e. the packing of fibrous particles, is important to the reinforcement of composite materials. It is very useful to develop a general predictive method for the optimum selection of particle mixtures for the property control of ceramic or composite products. This paper presents such a mathematical model developed on the basis of the similarity analysis between the spherical and non-spherical particle packings and assesses its applicability to the packing of fibrous particles with discrete and/or continuous length distributions. The results indicate that the model can predict this packing system well and hence provide an effective way to solve various packing problems in the composite materials processing.