Synthesis,Structure and Photoluminescence of a New Ir Complex Based on Pyridine-2,3-dicarboxylic Acid

A new complex Ir（ppy）2（Hpda）（Hppy=2-phenylpyridine, H2pda=pyridine-2,3-dicarboxylic acid） has been synthesized and characterized. According to single-crystal X-ray diffraction analyses, the title complex crystallizes in the monoclinic system, space group P21/n with a=8.5708（10）, b=22.685（2）, c=12.5722（15） , β=96.19（1）°, V=2430.2（5） 3, C（29）H（20）N3O4 Ir, Mr=666.22, Z=4, Dc=1.833 g/cm3, F（000）=1304, μ=5.54 mm（-1）, λ（Mo Kα）=0.71073 , GOOF=1.02, the final R=0.049 and w R=0.119 for 4680 independent reflections with Rint=0.069. The title complex is of mononuclear structure. Intermolecular C–H···O hydrogen bonds and π-π stacking interactions result in the formation of a 3D supramolecular network. Photoluminescent spectra show that one intense emission band with the maximum of 516 nm can be observed in the title complex.

ANALYSIS OF COMPLEX STRESS INTENSITIES FOR CRACKED LAMINATES

Classical plate theory has been used to find out interfacial stress intensity factors in composite laminates. By using a well-known relation between the crack-tip energy release rate and the complex stress intensity factor. a closed-form solution for complex. Stress intensity in terms of external loading and a mode mix parameter for fairly. general composite laminates is given. Then a procedure for determining this mode mix. parameter is presented. followed by numerical results for some laminates. Small scale contact condition is expressed in terms of external loading In particular, a symmetric property of interfacial toughness curye is proven. Finally. the accuracy of failure load predicled by elininating oscllation index is discussed. and an example is presented to show the validity and limitation of β=0 approximation.

Pressure and velocity cross-spectrum of normal modes in low-frequency acoustic vector field of shallow water and its application

The pressure and horizontal particle velocity combined descriptions in the very low frequency acoustic field of shallow wa- ter integrated with the concept of effective depth of Pekeris wave- guide is proposed, especially the active component of the pressure and horizontal particle velocity cross-spectrum, also called ho- rizontal complex cross acoustic intensity, when only two normal modes are trapped in the waveguide. Both the approximate theo- retic analysis and the numerical results show that the sign of the horizontal complex cross acoustic intensity active component is independent of the range when vertically deployed receiving dual sensors are placed in appropriate depths, the sum of which is equal to the waveguide effective depth, so it can be used to tell whether the sound source is near the surface or underwater; while the range rate is expected to be measured by utilizing the sign distribution characteristic of the reactive component. The further robustness analysis of the depth classification algorithm shows that the existence of shear waves in semi infinite basement and the change of acoustic velocity profiles have few effects on the application of this method, and the seabed attenuation will limit the detection range, but the algorithm still has a good robustness in the valid detection range.

Anti-plane analysis of semi-infinite crack in piezoelectric strip

Using the complex variable function method and the technique of the conformal mapping, the fracture problem of a semi-infinite crack in a piezoelectric strip is studied under the anti-plane shear stress and the in-plane electric load. The analytic solutions of the field intensity factors and the mechanical strain energy release rate are presented under the assumption that the surface of the crack is electrically impermeable. When the height of the strip tends to infinity, the analytic solutions of an infinitely large piezoelectric solid with a semi-infinite crack are obtained. Moreover, the present results can be reduced to the well-known solutions for a purely elastic material in the absence of the electric loading. In addition, numerical examples are given to show the influences of the loaded crack length, the height of the strip, and the applied mechanical/electric loads on the mechanical strain energy release rate.