Exploring the resonant vibration of thin plates: Reconstruction of Chladni patterns and determination of resonant wave numbers.

The Chladni nodal line patterns and resonant frequencies for a thin plate excited by an electronically controlled mechanical oscillator are experimentally measured. Experimental results reveal that the resonant frequencies can be fairly obtained by means of probing the variation of the effective impedance of the exciter with and without the thin plate. The influence of the extra mass from the central exciter is confirmed to be insignificant in measuring the resonant frequencies of the present system. In the theoretical aspect, the inhomogeneous Helmholtz equation is exploited to derive the response function as a function of the driving wave number for reconstructing experimental Chladni patterns. The resonant wave numbers are theoretically identified with the maximum coupling efficiency as well as the maximum entropy principle. Substituting the theoretical resonant wave numbers into the derived response function, all experimental Chladni patterns can be excellently reconstructed. More importantly, the dispersion relationship for the flexural wave of the vibrating plate can be determined with the experimental resonant frequencies and the theoretical resonant wave numbers. The determined dispersion relationship is confirmed to agree very well with the formula of the Kirchhoff-Love plate theory.

Manifesting the evolution of eigenstates from quantum billiards to singular billiards in the strongly coupled limit with a truncated basis by using RLC networks.

The coupling interaction between the driving source and the RLC network is explored and characterized as the effective impedance. The mathematical form of the derived effective impedance is verified to be identical to the meromorphic function of the singular billiards with a truncated basis. By using the derived impedance function, the resonant modes of the RLC network can be divided into the open-circuit and short-circuit states to manifest the evolution of eigenvalues and eigenstates from closed quantum billiards to the singular billiards with a truncated basis in the strongly coupled limit. The substantial differences of the wave patterns between the uncoupled and strongly coupled eigenmodes in the two-dimensional wave systems can be clearly revealed with the RLC network. Finally, the short-circuit resonant states are exploited to confirm that the experimental Chladni nodal-line patterns in the vibrating plate are the resonant modes subject to the strong coupling between the oscillation system and the driving source.

Level statistics and eigenfunctions of square torus billiards: manifesting the transition from regular to chaotic behaviors.

We thoroughly analyze the level statistics and eigenfunctions in concentric as well as nonconcentric square torus billiards. We confirm the characteristics of quantum and classical correspondence and the existence of scarred and superscarred modes in concentric square torus billiards. Furthermore, we not only verify that the transition from regular to chaotic behaviors can be manifested in nonconcentric square torus billiards, but also develop an analytical distribution to excellently fit the numerical level statistics. Finally, we intriguingly observe that numerous eigenstates commonly exhibit the wave patterns to be an ensemble of classical diamond trajectories, as the effective wavelengths are considerably shorter than the size of internal hole.

Wave pattern and weak localization of chaotic versus scarred modes in stadium-shaped surface-emitting lasers.

We explore the lasing mode selection between the chaotic and scarred modes in stadium-shaped vertical-cavity surface-emitting lasers (VCSELs). Experimental results reveal that the spatial gain distribution in the active layer of a VCSEL can be modified via the aperture size to favor the generation of either the chaotic or the scarred modes. Experimentally obtained chaotic and scarred modes are further employed to perform statistical analysis of wave function intensities for making a comparison with predictions based on the nonlinear σ model. We verify that the scarring effect can be quantitatively relevant to the weak-localization correction in the intensity probability distribution.

Manifestation of quantum-billiard eigenvalue statistics from subthreshold emission of vertical-cavity surface-emitting lasers.

We report that the subthreshold emission spectra of vertical-cavity surface-emitting lasers (VCSELs) can be analogously used to manifest the quantum-billiard energy spectra. The Fourier-transformed distributions of the subthreshold emission spectra are demonstrated to display various peak structures that are in good agreement with the results of the quantum-billiard model. We also verify that the statistical analyses of the nearest-neighbor eigenvalue spacing distributions obey a Poisson distribution for an equilateral-triangular device and a Wigner distribution for a stadium-shaped device.

Millijoule-level Yb-doped photonic crystal fiber laser passively Q-switched with AlGaInAs quantum wells.

We report on a millijoule-level Yb-doped photonic crystal fiber (PCF) laser passively Q-switched with AlGaInAs quantum wells (QWs). Three types of AlGaInAs devices with different QW numbers are fabricated to investigate the performance. With 50 groups of three AlGaInAs QWs as a saturable absorber (SA), the PCF laser generates an average power of 7.1 W with a pulse repetition rate of 6.5 kHz at a pump power of 16 W, corresponding to the pulse energy of 1.1 mJ. The maximum peak power is up to 110 kW.

Rheological characteristics and morphology of dialdehyde starch/meat composites during heating.

Dialdehyde starch (DAS) was added to pork ham batter. The effects of DAS on the meat protein gel during heating were investigated using thermal and rheological analyses. In this study, the degree of DAS oxidation was controlled by the reaction time. The DSC thermogram showed that increasing the degree of oxidation resulted in DAS having a higher gelatinization temperature and lower heat absorption. In dialdehyde starch/meat (DAS/M) composites, meat protein reduced the availability of water to starch and raised the gelatinization temperature and heat absorbed by the composites. The G'(max) of the composites was greater than the linear combination of their components. The rheological properties of DAS were a major factor affecting the properties of its composites. Scanning electron microscopy and light microscopy with the aid of histologic technique revealed the network and distribution of DAS and DAS/M composites. The protein matrix formed the backbone of the network and gelatinized starch was trapped in the protein structure.

Cloning, characterization and physical mapping of three cervid satellite DNA families in the genome of the Formosan muntjac (Muntiacus reevesi micrurus).

Due to their high sequence diversity even among closely related species, satellite DNA sequences can be a useful molecular marker for phylogenetic and taxonomic analyses. To characterize the satellite DNA in the genome of a native muntjac species of Taiwan, the Formosan muntjac, satellite DNA clones representing three different cervid satellite DNA families from this species were isolated and analyzed. Genomic organization study of these satellite DNAs was also undertaken. Three Formosan muntjac satellite DNA clones were obtained and designated as FM-satI (1,391 bp), FM-satII (1,143 bp) and FM-satIV (1,103 bp), and found to share approximately 82, 81 and 98% sequence homology with the Chinese muntjac satellite I clone (C5), Indian muntjac satellite II clone (Mmv-0.7) and Chinese muntjac satellite IV clone (MR-1.0), respectively. These three satellite DNA families are organized in a pter<--FM-satII-FM-satIV-FM-satI-->qter orientation in the centromeric region with satII closely associated with the telomeric sequences. Satellite DNA sequence comparison, in combination with chromosome data concludes that the Formosan muntjac is likely a subspecies of M. reevesi, closely related to the Chinese muntjac. With the kinetochore satellite II DNA co-localizing with the telomeric sequences, the Formosan muntjac chromosomes could be truly telocentric.

Cytotoxic prenylated depsidones from Garcinia parvifolia.

Leaf extracts of Garcinia parvifolia provided relatively high yields of four novel, cytotoxic prenylated depsidones. The structures were determined mainly by detailed NMR spectral analysis and X-ray crystallography.

The inhibition of cytoplasmic acetoacetyl-CoA thiolase by a triyne carbonate (L-660, 631).

The compound L-660, 631 (2-oxo-5-(1-hydroxy-2,4,6-heptatriynyl)-1,3-dioxolane-4 heptanoic acid), a natural product isolated from an Actinomycete culture, was found to inhibit rat liver cytosolic acetoacetyl-CoA thiolase, the first step in the cholesterol biosynthesis pathway, with an IC50 of 1.0 x 10(-8) M. The inhibitor had no effect on other sulfhydryl containing enzymes of lipid synthesis such as HMG-CoA synthase, HMG-CoA reductase, and fatty acid synthase. When tested in cultured human liver Hep G2 cells the compound inhibited the incorporation of 14C-acetate and 14C-octanoate into sterols 56% and 48% respectively at 3 x 10(-6) M with no effect on fatty acid synthesis. No noticeable effect was seen on fatty acid biosynthesis. This strongly suggests that the locus of inhibition of acetate incorporation into sterols found with this compound is the acetoacetyl-CoA thiolase step in the cholesterol biosynthesis pathway.