Optimization of miniature coarse wavelength division multiplexing module

This paper provides a noval solution to optimize the characteristics of a miniature coarse wavelength division multiplexing (mini-CWDM) module by employing collimators with plano-convex rod lenses of different radii. The 8-channel modules before optimization show maximum loss of 0.77 dB and nonuniformity of 0.34 dB. After optimization, the maximum loss and nonuniformity are reduced to 0.50 dB and 0.11 dB, respectively.     

Bondi-Sachs metrics and photon rockets

We study the Bondi-Sachs rockets with nonzero cosmological constant. We observe that the acceleration of the systems arises naturally in the asymptotic symmetries of (anti-) de Sitter spacetimes. Assuming the validity of the concepts of energy and mass previously introduced in asymptotically flat spacetimes, we find that the emission of pure radiation energy balances the loss of the Bondi mass in certain special families of the Bondi-Sachs rockets, so in these there is no gravitational radiation.     

A fluorine-contained copolymer ultra-thin film: Stability and electrochemical corrosion behavior

A novel fluorine-contained random copolymer (2,3,4,5,6-pentafluorostyrene)-r-poly(4-vinyl benzocyclobutene) (P(PFSt-r-4-VBCB)) was synthesized, and then spin-coated onto Si substrates followed by thermal cross-linking to produce the copolymer ultra-thin films. Although the surface modification with the P(PFSt-r-4-VBCB) film was simple and did not rely on special surface chemical reactions, the film could decrease the surface energy significantly, more importantly; the film demonstrated excellent stability and corrosion resistance. This random copolymer film could find broad applications in modifying various solid surfaces to enhance the properties such as corrosion resistance and solvent resistance.     

Study of Fe/Mo multilayer systems by SFM and AES

Received: 13 August 1998 / Published online: 10 February 1999     

The detection of HBV DNA with gold-coated iron oxide nanoparticle gene probes

Gold-coated iron oxide nanoparticle Hepatitis B virus (HBV) DNA probes were prepared, and their application for HBV DNA measurement was studied. Gold-coated iron oxide nanoparticles were prepared by the citrate reduction of tetra-chloroauric acid in the presence of iron oxide nanoparticles which were added as seeds. With a fluorescence-based method, the maximal surface coverage of hexaethiol 30-mer oligonucleotides and the maximal percentage of hybridization strands on gold-coated iron oxide nanoparticles were (120 ± 8) oligonucleotides per nanoparticle, and (14 ± 2%), respectively, which were comparable with those of (132 ± 10) and (22 ± 3%) in Au nanoparticle groups. Large network aggregates were formed when gold-coated iron oxide nanoparticle HBV DNA gene probe was applied to detect HBV DNA molecules as evidenced by transmission electron microscopy and the high specificity was verified by blot hybridization. Our results further suggested that detecting DNA with iron oxide nanoparticles and magnetic separator was feasible and might be an alternative effective method.     

Passive adaptive control of chaos in synchronous reluctance motor

The performance of synchronous reluctance motor （SynRM） degrades due to chaos when its systemic parameters fall into a certain area. To control the undesirable chaos in SynRM, a passive control law is presented in this paper, which transforms the chaotic SynRM into an equivalent passive system. It is proved that the equivalent system can be asymptotically stabilized at the set equilibrium point, namely, chaos in SynRM can be controlled. Moreover, in order to eliminate the influence of undeterministic parameters, an adaptive law is introduced into the designed controller. Computer simulation results show that the proposed controller is very effective and robust against the uncertainties in systemic parameters. The present study may help to maintain the secure operation of industrial servo drive system.     

Shrinkage-divergence-proximity locally linear embedding algorithm for dimensionality reduction of hyperspectral image

Existing manifold learning algorithms use Euclidean distance to measure the proximity of data points. However, in high-dimensional space, Minkowski metrics are no longer stable because the ratio of distance of nearest and farthest neighbors to a given query is almost unit. It will degrade the performance of manifold learning algorithms when applied to dimensionality reduction of high-dimensional data. We introduce a new distance function named shrinkage-divergence-proximity (SDP) to manifold learning, which is meaningful in any high-dimensional space. An improved locally linear embedding (LLE) algorithm named SDP-LLE is proposed in light of the theoretical result. Experiments are conducted on a hyperspectral data set and an image segmentation data set. Experimental results show that the proposed method can efficiently reduce the dimensionality while getting higher classification accuracy.     

Spectral analysis and numerical simulation for second order elliptic operator with highly oscillating coefficients in perforated domains with a periodic structure

This paper discusses the spectral properties and numerical simulation for the second order elliptic operators with rapidly oscillating coefficients in the domains which may contain small cavities distributed periodically with period ε. A multiscale asymptotic analysis formula for this problem is obtained by constructing properly the boundary layer. Finally, numerical results are given, which provide a strong support for the analytical estimates