Search

On silicate optical glass substrate, buried optical waveguide stacks were obtained. The stacks were composed of two layers of buried optical channel waveguide at different depth beneath the glass substrate surface, and each layer was manufactured by thermal Ag/Na ion-exchange and field-assisted ion-diffusion. Microstructure of the optical waveguide chips was observed with optical microscope, and insertion loss of each layer in waveguide stacks is measured. Results show that the buried waveguide stack is composed of two layers of buried waveguide with their core center located at 14 μm and 35 μm, respectively. Beneath the glass surface, core dimension of top layer and bottom layer waveguide are 12 μm×7 μm and 9 μm×8 μm, respectively. Waveguides in both layers are single mode at operating wavelength of 1.55 μm. There is no directional coupling observed between waveguides at different layers. Insertion loss characterization indicates that propagation loss of both layers in the stack is 0.12 dB/cm, and coupling losses with single mode fiber are 0.78 dB/facet and 0.73 dB/facet, for top and bottom layer waveguides, respectively. The analysis suggests that this kind of optical waveguide stack is promising in application of high density integration of glass-based optical chip.

Low-rate Denial of Service (LDoS) attacks exploit the deficiencies of the minimum RTO of TCP to send out attack packets in short-duration periodic pulses with low average volume traffic in order to throttle TCP throughput. It is hard to detect an LDoS attack by most available detection schemes, which are triggered by high-rate traffic based on time average statistics. In this paper, the method of Multiple Sampling Averaging Based on Missing Sampling (MSABMS) is used to detect LDoS attacks based on the model of small signal for the first time. In the proposed approach, statistics on the packets are taken within 30 s with the sampling interval of 10 ms (3000 sampling points in total), and the statistical results are compared with a threshold for identifying the LDoS attacks. Furthermore, an eigenvalue-estimating matrix is established to estimate the attack period after the detection of LDoS attacks. Simulation results in NS-2 environment show that the proposed approach can be used to detect the LDoS attack effectively.

An indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) was developed for the quantitative detection of bifenthrin. Two haptens, LBc ((2-methyl[1,1′-biphenyl]-3-methoxy) carbonyl propionic acid) carbonyl propionic acid) and LBy ((2-methyl[1,1′-biphenyl]-3-yl)carboxylic acid), were synthesized from 2-methyl-3-phenylbenzyl alcohol, a metabolite of bifenthrin. The LBc was conjugated to bovine serum albumin (BSA) for the immunogen by the carbodiimide method, and the LBc and LBy were conjugated to ovalbumin (OVA), respectively, for the coating antigens by the mixed anhydride method. Polyclonal antibodies was raised against LBc-BSA conjugate in rabbits and hapten-OVA conjugates as coating antigens were screened and selected for the assay in the homologous and heterologous ELISA systems, and the titers of antiserum (5.12 × 10 4 ) were determined by non-competitive ELISA procedure. Under the optimum assay conditions of pH 7.5, PBS of 0.3 M Na + and 30% methanol, the heterologous assay system was more sensitive. The IC 50 value for bifenthrin was (2.16 ± 0.32) mg l −1 , and the detection limit was (0.016 ± 0.002) mg l −1 . Pyrethroids, such as cyhalothrin, deltamethrin, cypermethrin, fenvalerate, fenpropathrin, and pyrethroid metabolite, 3-phenoxybenzoic acid, did not cross-react significantly in this assay.

A compact arrayed-waveguide grating (AWG) on the silicon-on-insulator material is designed and fabricated with employment of waveguide-integrated turning mirrors (WITMs). By properly setting the incident angle with the value of 45?, the effective area of the WITM AWG is only 1.15?cm?1.15?cm with the arrayed waveguide area of 0.6?cm?0.6?cm. The crosstalk of the fabricated 1?6 AWG is better than -19?dB. The on-chip insertion loss is about -8.8?dB and the output nonuniformity is less than 0.6?dB. The polarization-dependent central wavelength shift is about 0.048?nm and the polarization dependent loss is neglectable.