Electrospray ionization from a droplet deposited on a surface-modified glass rod

This paper reports development of a non-mechanical electrospray ionization (ESI) method to generate electrospray from a droplet deposited on an optical fiber coated with a thin gold or Nafion film. Modification of the surface of the optical fiber in this manner increases its wettability, such that a droplet of the aqueous sample solution can adhere sufficiently strongly to the tip of the fiber. The aqueous sample solution was deposited near the tip of the fiber with a micropipette. When a high voltage (2,000 V) was applied to the fiber by electrical connection through the gold film, the sample solution moved and hung at the tip of the fiber. Simultaneously, ESI was generated from the sample droplet. Multiply charged peptide and protein ions were detected by connecting the ESI source to a quadrupole mass analyzer.     

A continuation–domain decomposition algorithm for bifurcation problems

We study numerical solution branches of certain parameter-dependent problems defined on compact domains with various boundary conditions. The finite differences combined with the domain decomposition method are exploited to discretize the partial differential equations. We propose efficient numerical algorithms for solving the associated linear systems and for the detection of bifurcation points. Sample numerical results are reported. This revised version was published online in August 2006 with corrections to the Cover Date.     

Wiggly technique for broadband non-uniform line couplers

A new and successful wiggly technique is proposed for the design of broadband non-uniform line couplers, where the coupler is wiggled with rectangular teeth on the inner and outer edges of coupled conductors. Compared with other reported quadrature couplers, this design offers a fully planar structure without bond wires or dielectric overlaps. A fabricated 2-18 GHz microstrip coupler was measured and significant performance improvement is reported.     

Fast fractal image compression using spatial correlation

Fractal image compression is time consuming in the encoding process. The time is essentially spent on the search for the best-match block in a large domain pool. In this paper, the spatial correlations in both the domain pool and the range pool are utilized to reduce the searching space. With this technique, the encoding speed is 2.6 times faster than that of the full search method while the quality of the retrieved image is almost the same. Moreover, since the searching space is limited to the matched blocks of the previous range blocks, fewer bits are required to represent the transform. The bit rate is thus improved by about 20%.     

Nonisothermal crystallization behavior of syndiotactic polystyrene/montmorillonite nanocomposites

X‐ray diffraction methods and differential scanning calorimetry were used to investigate the crystalline structure and crystallization kinetics of syndiotactic polystyrene (sPS)/clay nanocomposites. X‐ray diffraction data showed the presence of polymorphism in sPS/montmorillonite (MMT) nanocomposites, which was strongly dependent on the processing conditions (premelting temperature and cooling rate) of the sPS/MMT nanocomposites and on the content of MMT in the sPS/MMT nanocomposites. The α‐crystalline form could be transformed into β‐crystalline forms at higher premelting temperatures. The nonisothermal melt‐crystallization kinetics and melting behavior of the sPS/MMT nanocomposites were also studied at various cooling rates. The correlation of the crystallization kinetics, melting behavior, and crystalline structure of the sPS/MMT nanocomposites was examined. The results indicated that the addition of a small amount of MMT to sPS caused a change in the mechanism of nucleation and the crystal growth of the sPS crystallite. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 560–570, 2003     

MCPIC: a video coding algorithm for transmission and storageapplications

The Moving Picture Experts Group (MPEG) of ISO is considering a standard for storage applications below 1.5 Mb/s. A video coding algorithm developed at Bellcore that has been proposed as a contribution to the standardization activity of ISO/MPEG is described. The following characteristics of the algorithm are described. The following characteristics of the algorithm are described in detail: frequent periodic reset of the temporal predictor (to provide random access), interpolative coding of every second frame, flexibility of providing adaptive Huffman code tables for digital-storage-media (DSM)-based applications (not feasible for real-time transmissions), 1/2-pel accuracy in motion estimation, and optional quantization matrix. Additional features of reverse playback, fast searches, and random access are described     

A 2.5-D dynamic model for a saturated porous medium: Part I. Green’s function

Based on Biot’s theory, the dynamic 2.5-D Green’s function for a saturated porous medium is obtained using the Fourier transform and the potential decomposition methods. The 2.5-D Green’s function corresponds to the solutions for the following two problems: the point force applied to the solid skeleton, and the dilatation source applied within the pore fluid. By performing the Fourier transform on the governing equations for the 3-D Green’s function, the governing differential equations for the two parts of the 2.5-D Green’s function are established and then solved to obtain the dynamic 2.5-D Green’s function. The derived 2.5-D Green’s function for saturated porous media is verified through comparison with the existing solution for 2.5-D Green’s function for the elastodynamic case and the closed-form 3-D Green’s function for saturated porous media. It is further demonstrated that a simple form 2-D Green’s function for saturated porous media can be been obtained using the potential decomposition method.