Encapsulation of tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) complex linked with dendrons in sol-gels: Stable optical sensing membranes for dissolved oxygen

To circumvent the leaching problem of optical sensing membranes used for dissolved oxygen (DO) measurements, the encapsulation of Ru(II) complexes linked with bulky dendron(s) in a sol-gel matrix was investigated. A dendron, readily formed via chemical transformations such as amidation and catalytic reduction, was covalently incorporated into tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) complex, leading to an increase in the size and lipophilicity of dye molecules. Sol-gel-based sensing membranes encapsulating these Ru(II) complexes displayed a strong luminescence emission at 590 nm induced by radiation at 480 nm, and showed excellent DO sensing properties and stability for repeated measurements in aqueous solution. The encapsulation of the dendron-incorporated Ru(II) complexes in sol-gels prevented the dyes from leaching out of the membranes.     

Nonexistence of asymptotically self-similar singularities in the Euler and the Navier–Stokes equations

In this paper we rule out the possibility of asymptotically self-similar singularities for both of the 3D Euler and the 3D Navier–Stokes equations. The notion means that the local in time classical solutions of the equations develop self-similar profiles as t goes to the possible time of singularity T. For the Euler equations we consider the case where the vorticity converges to the corresponding self-similar voriticity profile in the sense of the critical Besov space norm, . For the Navier–Stokes equations the convergence of the velocity to the self-similar singularity is in L ^q (B(z,r)) for some , where the ball of radius r is shrinking toward a possible singularity point z at the order of as t approaches to T. In the convergence case with we present a simple alternative proof of the similar result in Hou and Li in arXiv-preprint, math.AP/0603126. This work was supported partially by KRF Grant(MOEHRD, Basic Research Promotion Fund) and the KOSEF Grant no. R01-2005-000-10077-0.     

Precise mass measurement of a double-stranded 500 base-pair (309 kDa) polymerase chain reaction product by negative ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry

Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICRMS) has been used to determine the mass of a double-stranded 500 base-pair (bp) polymerase chain reaction (PCR) product with an average theoretical mass of the blunt-ended (i.e. unadenylated) species of 308 859.35 Da. The PCR product was generated from the linearized bacteriophage Lambda genome which is a double-stranded template. Utilization of ethanol precipitation in tandem with a rapid microdialysis step to purify and desalt the PCR product was crucial to obtain a precise mass measurement. The PCR product (0.8 pmol/μL) was electrosprayed from a solution containing 75% acetonitrile, 25 mM piperidine, and 25 mM imidazole and was infused at a rate of 200 nL/min. The average molecular mass and the corresponding precision were determined using the charge-states ranging from 172 to 235 net negative charges. The experimental mass and corresponding precision (reported as the 95% confidence interval of the mean) was 309 406 +/- 27 Da (87 ppm). The mass accuracy was compromised due to the fact that the PCR generates multiple products when using Taq polymerase due to the non-template directed 3'-adenylation. This results in a mixture of three PCR products with nearly identical mass (i.e. blunt-ended, mono-adenylated and di-adenylated) with unknown relative abundances that were not resolved in the spectrum. Thus, the experimental mass will be a weighted average of the three species which, under our experimental conditions, reflects a nearly equal concentration of the mono- and di-adenylated species. This report demonstrates that precise mass measurements of PCR products up to 309 kDa (500 bp) can be routinely obtained by ESI-FTICR requiring low femtomole amounts. Copyright 1999 John Wiley & Sons, Ltd.     

Transparent and Conductive Polyethylene Oxide Film by the Introduction of Individualized Single‐Walled Carbon Nanotubes

It is demonstrated that an optically transparent and electrically conductive polyethylene oxide (PEO) film is fabricated by the introduction of individualized single‐walled carbon nanotubes (SWNTs). The incorporated SWNTs in the PEO film sustain their intrinsic electronic and optical properties and, in addition, the intrinsic properties of the polymer matrix are retained. The individualized SWNTs with smaller diameter provide high transmittance as well as good electrical conductivity in PEO films.

     

Self-assembly of Ag nanopowder on OTS-patterned glass

Ag ink was spontaneously patterned on glass substrate by using the surface energy difference of a pre-patterned octadecyltrichlorosilane (OTS) layer. Ag ink was confined into the hydrophilic area, where OTS layer was not formed. OTS layer was selectively transferred by micro-contact printing (μCP) method and significantly decreased surface energy. As a result, surface of glass substrate was separated as hydrophobic and hydrophilic with and without OTS layer, respectively. Ag line could be successfully patterned with the width of below 10 μm on the glass. The patterned Ag line was dense and abrupt on the edge and the thickness was about 0.25 μm. Ag film showed good adhesion on a glass substrate after anneal above 200 °C. The minimum resistivity was about 4 μΩ cm.     

Measurement of residual stresses in film insert molded parts with complex geometry

Residual stress distribution of injection molded and film insert injection molded products were measured by using the hole drilling method after ejection and annealing, respectively. Non-isothermal three dimensional flow analysis was carried out for filling, packing and cooling stages. The flow analysis results were transported to a finite element stress analysis program and three dimensional stress analysis was performed for prediction of residual stresses in the parts. For comparison, residual stress distribution was measured by the layer removal method and calculated by the three dimensional numerical simulation in order to evaluate accuracy of the hole drilling method. Residual stress distributions obtained by both experiments and numerical methods accorded well with each other. Therefore, the hole drilling method is a reliable and useful method for measurement of residual stresses in injection molded parts, especially, products with complex geometry.     

Effect of proton irradiation on electrical properties of a-As2S3

This paper reports the effect of proton irradiation on the electrical properties of a-As₂S₃ in the temperature range of 323–418 K and frequency range 0.1–100 kHz. The variation of transport property is studied with proton irradiation dose (1 × 10¹³ ions/cm² and 1 × 10¹⁵ ions/cm²). It has been observed that proton irradiation changes the dc conductivity (σ_dc), dc activation energy (ΔE_dc) and ac conductivity (σ_ac(ω)). The σ_dc and σ_ac(ω) increases with dose of proton irradiation. The value of frequency exponent (s) decreases with the temperature and irradiation dose. These results are explained in terms of change in density of defect states in these glasses.     

XAS and XMCD studies of amorphous FeCo-based ribbons

This paper reports x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD) studies at Fe L_3,2 and Co L_3,2-edges to investigate the electronic structure of (Fe_100 ? xCo_x)₇₈Si₉Nb₃B₉Cu₁ (0 < x < 95) alloys. The influence of controlled Co addition on electronic structural and magnetic properties of (Fe_100 ? xCo_x)₇₈Si₉Nb₃B₉Cu₁ (x = 0, 20, 40, and 60) alloys has been investigated and it has been observed that Co exists as Co²⁺/Co³⁺, while Fe exists as a mixture of Fe⁰ (metallic) and Fe²⁺. The XMCD studies confirm these results and reveal that Co-ions are responsible for the room temperature ferromagnetism (RTFM) in the system, while at Fe L_3,2-edge it shows a diamagnetic behavior.