Surface tension and viscosity measurements of liquids with the survismeter: a single instrumental unit

Surface tension (γ) and viscosity (η) data of aqueous solutions of the deoxyadenosine (DOA) and the deoxyribose (DOR) sugars have been measured with the survismeter, a new instrument, along with tetrahydrofuran (THF), dimethylformamide (DMF), acetonitrile and dimethylsulphoxide (DMSO) solvents. The same properties have also been measured with a stalagmometer and a viscosimeter, respectively, which afford the same information, albeit at the expense of a larger amount of chemicals and solvents. We obtain comparatively better accuracy in both kinds of measurements than with conventional methods. Therefore, the survismeter lends itself as a simple and reliable instrument.     

Theoretical analysis on capillary adhesion of microsized plates with a substrate

The stiction of a thin plate induced by the capillary force has attracted much attention in the broad range of applications. A novel method is presented to calculate the capillary adhesion problem of the plate through analytical method. The expressions of the surface energy, the strain energy and the total potential energy of the plate-substrate system have been analyzed and delineated. By means of continuum mechanics and the principle of minimum potential energy, the governing equation of the plate with an arbitrary shape and the corresponding transversality boundary condition due to the moving bound have been derived. Then the critical adhesion radius of the circular plate has been solved according to the supplementary transversality condition. Thus the deflections of the plates are analytically calculated with different critical adhesion radii. The results may be beneficial to the engineering application and the micro/nanomeasurement.     

Size-dependent elastic properties of micro- and nano-honeycombs

Detailed mathematical derivation and simple closed form results for the size-dependent elastic properties of micro- and nano-sized honeycombs are presented in this paper. The results indicate that at micrometer scale, strain gradient has a dominant effect and at nano-meter scale, surface elasticity dominates the effect on the honeycomb elastic properties. The in-plane elastic properties of a nano- or micro-honeycomb could be controlled to vary over a range of around 10% by adjusting the initial stress in the cell walls by applying an electric potential. In addition, the bending and shear rigidities of some commonly used micro- and nano-structural elements have been obtained and presented in this paper, which could be of important applications in the design of MEMS and NEMS.     

Variational derivation of improved KP-type of equations

The Kadomtsev-Petviashvili equation describes nonlinear dispersive waves which travel mainly in one direction, generalizing the Korteweg-de Vries equation for purely uni-directional waves. In this Letter we derive an improved KP-equation that has exact dispersion in the main propagation direction and that is accurate in second order of the wave height. Moreover, different from the KP-equation, this new equation is also valid for waves on deep water. These properties are inherited from the AB-equation (E. van Groesen, Andonowati, 2007 [1]) which is the unidirectional improvement of the KdV equation. The derivation of the equation uses the variational formulation of surface water waves, and inherits the basic Hamiltonian structure.     

Studies of the regioselective ring-opening–closing mode of functionally different thiazolidine type enaminones: en route to the synthesis of trithiaazapentalene derivatives

Trithiaazapentalene derivatives were prepared by the reaction of 2-alkylidene-4-oxothiazolidines with Lawesson's reagent. They are classified as two structurally different trithiaazapentalene compounds that have different contributions of monocyclic 1,2-dithiole and 1,2,4-dithiazole structures and degrees of aromaticity of the bicyclic trithiaazapentalene system. The electron-donating ability of substituents at the C(5) position of the trithiaazapentalene system is recognized as the main cause for changes in π-electron distribution. This is the first complete study of substituent effects on the structure of trithiapentalenes.     

Meter-long CeO2/YSZ/Y2O3 buffer layers for YBCO coated conductors using DC reactive sputtering

This paper reports CeO₂/YSZ/Y₂O₃ buffer layers deposited on biaxially textured NiW substrates by DC reactive sputtering in a reel-to-reel system. The effect of partial pressure of water vapor (P_H2O) on surface morphology and orientation of the Y₂O₃ films was examined. The obtained CeO₂/YSZ/Y₂O₃ buffer layers exhibit a highly biaxial texture, with in- and out-of-plane FWHM values respectively in the range of 6.0–7.0° and 4.5–5.5°. Crystallographic consistency of CeO₂/YSZ/Y₂O₃ along meter length is excellent. Atomic force microscope observation (AFM) reveals a smooth, continuous and crack-free surface with a Root-mean-square roughness (RMS) lower than 10 nm.     

Surface modification of an epoxy resin with polyamines via cyanuric chloride coupling

The presence of polyamine groups on the surface of dielectric resins potentially improves the adhesion with electrochemically deposited metals. In this article, first cyanuric chloride is covalently bound to the surface hydroxyl groups of the epoxy resin. The remaining reactive sites on the coupled cyanuric chloride molecule are then used to anchor polyamines. New data on the triazine coupling is presented. The surface reactions are monitored and characterized by means of ATR-IR, SEM-EDS, XPS and ToF-S-SIMS.     

Surface monitoring based on light scattering by metal nanosensors

Light scattering from objects in the proximity of surfaces is of fundamental importance in a variety of surface- and field-enhanced optical sensing, spectroscopy and microscopy applications. Here, we present surface monitoring techniques based on the spectral analysis of the scattered light by metal nanoparticles which act as sensors (nanosensors) of sample substrates interacting with them. We will focus on the detection of surface inhomogeneities by studying the modifications undergone by the local fields produced in the surrounding of the nanosensor, giving rise to spectral changes in its Plasmon Resonances. We will also describe an alternative technique where the sample information is obtained from the changes induced in the linear polarization degree of the far field scattered by the tip and due to the interaction with the sample.     

Synthesis of ZnO nanospheres with uniform nanopores by a hydrothermal process

ZnO nanospheres were successfully synthesized by a hydrothermal process (S1 sample) and a wet-chemical method (S2 sample). Following synthesis, calcination treatment at 450 °C was performed for the sample prepared by the wet-chemical method (S3 sample). All of the samples possessed a regular spherical shape. A polycrystalline wurtzite structure was confirmed in the S1 and S3 samples by X-ray diffraction and selected area electron diffraction, whereas a mixture of ZnO nanoparticles and amorphous materials was observed in the sample S2. The surface area and pore structure of the samples were investigated by nitrogen adsorption–desorption measurements. Uniform nanopores with a diameter of 4.07 nm were present in the S1 sample while a broad pore size distribution was obtained for the S2 and S3 samples. The highest surface area was obtained for the S1 sample and a possible formation mechanism was studied.     

When closed graph manifolds are finitely covered by surface bundles over S 1

The problem of deciding whether a graph manifold is finitely covered by a surface bundle over the circle is discussed in this paper. A necessary and sufficient condition in term of the solutions of a certain matrix equation is obtained, as well as a necessary condition which is easy to compute. Our results sharpen and extend the earlier results of J. Leucke-Y. Wu, W. Neumann, and S. Wang-F. Yu in this topic. Supported in part by NSFC