Nanoparticle‐Mediated Intervalence Charge Transfer: Core‐Size Effects

Two types of platinum nanoparticles (NPs) functionalized with ethynylferrocene were prepared. The subnanometer‐sized NPs (Pt₁₀eFc) showed semiconductor‐like characteristics with a bandgap of about 1.0 eV, and the other was metal‐like with a core size of about 2 nm (Pt₃₁₄eFc) and no significant bandgap. IR spectroscopic measurements showed a clear red‐shift of the C≡C and ferrocenyl ring =C?H vibrational energies with increasing particle core size owing to enhanced intraparticle charge delocalization between the particle‐bound ferrocenyl moieties. Electrochemical measurements showed two pairs of voltammetric peaks owing to intervalence charge transfer between the ferrocenyl groups on the nanoparticle surface, which was apparently weaker with Pt₁₀eFc than with Pt₃₁₄eFc. Significantly, the former might be markedly enhanced with UV photoirradiation owing to enhanced nanoparticle electronic conductivity, whereas no apparent effects were observed with the latter.     

Contact line mobility in liquid droplet spreading on rough surface

We quantitatively estimate the effect of the substrate roughness on the liquid droplet spreading. Since the droplet size is in the order of millimeters, the surface energy becomes the dominant factor. A nonequilibrium thermodynamics framework [Y.X. Gao, H. Fan, Z. Xiao, Acta Mater. 48 (2000) 863-874] seems feasible for describing the millimeter size droplet spreading on a solid substrate. Within the framework, there are two system constants, namely the mobilities of liquid/air surface and the triple joint contact line that need to be determined from experimental testing. In the present paper, we demonstrate the experimental process of determining the mobility of the contact line via a droplet spreading on a steel substrate. Particularly, we obtained the contact line mobility on a steel surface with various roughness values. It is shown that the mobility value is lower for a rougher surface.     

光的色散实验组合演示仪

针对沪科版八年级物理第四章第4节光的色散演示实验的不足,设计制作了一种光的色散实验组合演示仪,能够完成光的色散、光的混合和物体颜色共5个演示实验,帮助学生更好地理解相关概念和原理,从而提高课堂教学效果.     

Convergence to diffusion waves for solutions of Euler equations with time-depending damping on quadrant

This paper is concerned with the asymptotic behavior of the solution to the Euler equations with time-depending damping on quadrant(x,t)∈R~+×R~+,with the null-Dirichlet boundary condition or the null-Neumann boundary condition on u. We show that the corresponding initial-boundary value problem admits a unique global smooth solution which tends timeasymptotically to the nonlinear diffusion wave. Compared with the previous work about Euler equations with constant coefficient damping, studied by Nishihara and Yang(1999), and Jiang and Zhu(2009, Discrete Contin Dyn Syst), we obtain a general result when the initial perturbation belongs to the same space. In addition,our main novelty lies in the fact that the cut-off points of the convergence rates are different from our previous result about the Cauchy problem. Our proof is based on the classical energy method and the analyses of the nonlinear diffusion wave.     

Effect of the twisting chirality configuration on the electromechanical behavior of multilayer superconducting tapes

Seeking a geometry that can withstand greater transverse loads based on the electromechanical material properties of high-temperature superconducting (HTS) tape is an effective way of improving the transport performance of HTS cables. The cabling method requires the determination of the optimum twist angle of the HTS tape for withstanding transverse loads. This paper investigates the critical current characteristics of HTS tapes under combined deformation. The limit range of the twist angle under the combined deformation is measured and the optimum twist angle of the HTS tape is determined. The results show that the twisting chirality configuration obviously affects the bending strength of the HTS tape. In the elastic range, increasing the pre-twist angle increases the bending strength of the HTS tape, thereby improving the transport performance. In addition, a numerical model is built to further investigate the effect of the twisting chirality configuration on the electromechanical properties of the HTS tape, and the experimental results are explained. The experimental and simulation results generally agree well, and calculations show that there is always a sharp change in stress at the interface of different materials. These findings explain the mechanism of the effect of the twisting chirality configuration on the mechanical behavior and critical current of the HTS tape. They also provide a reference for cabling methodologies for the HTS cable configuration.     

An Effective Osteogenesis Porous CaP/Collagen Interface Compatible with Various Substrates Fabricated by Controlled Mineralization in a Delicately Adjustable Organic Matrix

Increasing bone formation on the surfaces of implants such as screws, plates, or shims holds great significance for clinical medicine. However, osteogenesis implant coatings that mimic natural bone in terms of both their components and structural features are still lacking. Here we report the biomimetic interface of calcium phosphate (CaP) in a collagen matrix fabricated by controlled mineralization that presents biomimetic porous features. The porous CaP/collagen interface, with a thickness of about 1 μm, significantly enhances osteogenesis, as verified at both the gene and protein levels as well as by in vivo experiments. Taking advantage of the generality of the method, the biomimetic interface was prepared on a variety of substrates, including conductive substrates, 3D metal meshes, plastic or elastic substrates, and even on filter papers. The adjustability and generality of the method have enabled new characterization tests to be developed during experiments on cells and thus should greatly facilitate clinical medicine and tissue engineering.     

Degradation of alkylbenzene sulfonate surfactants by pulsed ultrasound

The application of pulsed ultrasound for the degradation of the nonvolatile surfactants sodium 4-octylbenzene sulfonate (OBS) and sodium dodecylbenzenesulfonate (DBS) was investigated at a frequency of 354 kHz. By comparing the degradation rate constants with those of continuous wave (CW) ultrasound, observed pulse enhancements were found to be dependent on the pulse length, pulse ratio, initial concentration, and surface activity of the surfactants. For a pulse length of 100 ms and a pulse ratio of 1:1 (equal on/off times), the degradation rate constant of 1 mM OBS was nearly twice the value for CW. Furthermore, the degradation rate constant for 1 mM DBS increased significantly when sonicated under a pulse length of 100 ms and a pulse on/off ratio of 1:50. However, the degradation rate of 0.1 mM OBS increased by only 30% with a 100 ms pulse length and pulse ratio of 1:1 as compared to CW, indicating concentration dependence. The enhanced degradation of surfactants by pulsed ultrasound was attributed to the accumulation of surfactants on cavitation bubble surfaces. In addition, as compared to shorter pulse intervals, longer pulse intervals enhanced DBS degradation, indicating that DBS, a more surface active compound, accumulated and equilibrated with the bubble interface more slowly.     

A Multifaceted Mass Spectrometric Method to Probe Feeding Related Neuropeptide Changes in <Emphasis Type="Italic">Callinectes sapidus</Emphasis> and <Emphasis Type="Italic">Carcinus maenas</Emphasis>

Food intake is regulated by various neuromodulators, including numerous neuropeptides. However, it remains elusive at the molecular and cellular level as to how these important chemicals regulate internal processes and which regions of the neuronal organs are responsible for regulating the behavior. Here we report a comparative neuropeptidomic analysis of the brain and pericardial organ (PO) in response to feeding in two well-studied crustacean physiology model organisms, Callinectes sapidus and Carcinus maenas, using mass spectrometry (MS) techniques. A multifaceted MS-based approach has been developed to obtain complementary information on the expression changes of a large array of neuropeptides in the brain and PO. The method employs stable isotope labeling of brain and PO extracts for relative MS quantitation, capillary electrophoresis (CE)-MS for fractionation and high-specificity analysis, and mass spectrometric imaging (MSI) for in-situ molecular mapping of peptides. A number of neuropeptides, including RFamides, B-type allatostatins (AST-B), RYamides, and orcokinins exhibit significant changes in abundance after feeding in this investigation. Peptides from the AST-B family found in PO tissue were shown to have both altered expression and localization changes after feeding, indicating that they may be a class of vital neuropeptide regulators involved in feeding behavior.

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