Theoretical analysis of magnetic sensor output voltage

The output voltage is an important parameter to determine the stress state in magnetic stress measurement, the relationship between the output voltage and the difference in the principal stresses was investigated by a comprehensive application of magnetic circuit theory, magnetization theory, stress analysis as well as the law of electromagnetic induction, and a corresponding quantitative equation was derived. It is drawn that the output voltage is proportional to the difference in the principal stresses, and related to the angle between the principal stress and the direction of the sensor. This investigation provides a theoretical basis for the principle stresses measurement by output voltage.     

Pseudo-relaxor behaviour induced by Maxwell–Wagner relaxation

We performed a further investigation on the Maxwell–Wagner (MW) relaxation-induced relaxor-like dielectric response characterized by a broad peak in the real part of the dielectric permittivity as a function of temperature. Based on the double-layer MW model formulated by Catalan et al. (2000) [10], an empirical formula was derived to describe the temperature dependence of the peak intensity. It was also found that the temperature dependence of the peak position can be characterized by an Arrhenius-like relation. The differences between the true relaxor and MW-related relaxor behaviours are also discussed.     

Stable conformations of 12-crown-O3N and its Li+ complex in aqueous solution

Stable conformations of 12-crown-O3N and its Li complexes in aqueous solution were investigated. To calculate the free energy differences of conformers of 12-crown-O3N and its Li+ complex, our procedure was to make use of two programs, CONFLEX and BOSS. The former generates conformers, and the latter calculates the differences in free energy of solvation between two conformers in aqueous solution. It was confirmed that the present procedure is applicable in solving the question of what is the most stable conformation of 12-crown-O3N in aqueous solution. Results of the calculations suggest that the order of stability for conformers in a vacuum is different from that in aqueous solution. It was also confirmed that the coordination geometry of solvent waters to Li+ changes depending on the distance between the cation and the crown ring.     

Separation of proteins on surface-modified poly(dimethylsiloxane) microfluidic devices

Separation and detection of proteins have been realized on nonionic surfactant-modified poly(dimethylsiloxane) (PDMS) microfabricated devices with end-column amperometric detection. The hydrophobic PDMS channels are turned into hydrophilic ones after being modified with Brij35 and facilitate the separation of proteins. The coating can remarkably reduce the adsorption of large protein molecules and is stable in the range of pH 6-12. The detection of proteins in such channels needs less rinsing time and thus efficiency is raised. Even large molecules of proteins can also be detected with better reproducibility and enhanced plate numbers. The relative standard deviation (RSD) of the migration time for glucose oxidase (GOD) is 2.2% (n = 19). Separation of GOD and myoglobin has been developed in modified channels. Predominant operational variables, such as the coating conditions, the concentration of surfactant and buffer, are studied in detail.     

Reactivity of the Hydroxy Groups in Melezitose and Their Selective Protection

The reactivity of melezitose hydroxy groups was studied by tritylation in pyridine with subsequent acetylation. After partial detritylation of the products, acetyl group transfer from position 4 to 6 was observed. The structure of the prepared melezitose derivatives was established on the basis of their IR, ¹H, ¹³C, and ¹H-¹H COSY NMR, and mass spectra (fast atom bombardment), as well as from the results of model calculations performed with the aid of SGI Indigo Molecule-Pattern-Work-Station software package (Biosym) where the potential energy function was approximated with the CVFF potential. The reactivity of primary hydroxy groups in melezitose was found to decrease in the following order: 6' > 6 6' > 1'.     

Analysis of planar waveguides with index discontinuity or index slope discontinuity

In this paper, we propose a novel analytic transfer matrix method (ATMM) to the analysis of planar waveguides with index discontinuity or index slope discontinuity, for the cases when the conventional WKB method is no longer valid. We also analyze the physical insight of the approximations in WKB theory, and according to our research, the phase shift at the turning point is not /2, but exactly . Test calculations are done for an index profile with a known solution and the comparison shows that our method gives extremely accurate propagation constant.     

Effective generation of red-green-blue laser in a two-dimensional decagonal photonic superlattice

We demonstrate the effective generation of red, green and blue (RGB) light in a two-dimensional decagonal quasiperiodic LiNbO₃ nonlinear crystal. Owing to the unique abundance in reciprocal vectors (RVs), the RGB signals were generated directly by frequency doublings. Thus the conversion efficiencies of the RGB light were much higher than previously recorded. In addition, the same results were obtained when the crystal was rotated by integral multiples of π/5. This result will aid in the effective generation of RGB in multiple directions and may have important applications in laser-based projection displays. PACS 42.65.Ky; 42.72.Bj; 42.79.Nv