智能蓝光捕捉技术简述

为了防止有害光线对眼部的伤害,依视路集团研发出了智能蓝光捕捉技术,该技术可实现紫外线防护,符合新国标要求的蓝光防护,并维持色彩真实性。     

Round-trip time and dispersion optimization in a dual-wavelengthactively mode-locked Er-doped fiber laser including nonchirped fiberBragg gratings

Round-trip time and intracavity dispersion were optimized in a dual-wavelength actively mode-locked Er-doped fiber laser including two nonchirped fiber Bragg gratings. This optimization allowed to generate nearly transform-limited pulses as short as 16 and 13 ps at 1547 and 1562 nm, respectively, at a 3-GHz repetition rate only limited by the modulator bandwidth. In the experiment, the round-trip time difference between pulses at two wavelengths was adjusted using a fiber stretcher. Intracavity dispersion was managed at each wavelength separately     

Retrieving Optical Pulse Profiles Using a Nonlinear Optical Loop Mirror

A novel technique is proposed to characterize the power profile of short optical pulses using the transmission characteristic of a nonlinear optical loop mirror (NOLM). Under some assumptions, the power profile can be retrieved from pulse energy measurements at the NOLM output using a slow detection setup. As a fiber-based technique based on the Kerr effect, it does not require phase matching or tedious mechanical adjustments. The technique is able to characterize simultaneously pulse features from the picosecond to the nanosecond scale.     

Response of the Rhône deltaic margin to loading and subsidence during the last climatic cycle

Passive continental margin subsidence is initiated by the synrift mechanical stretching of the lithospheric upper brittle layer and continues during the postrift phase; the thermal cooling and contraction of the upwelled asthenosphere forces the margin to subside in addition to the overloads from sea water and sediments. Therefore, the total subsidence in stretched basins includes fault-controlled initial sinking, thermal subsidence and flexural isostatic compensations. Decoupling and estimating the different components of this subsidence from stratigraphic analysis and restricted geophysical and sedimentological databases remains problematic. In particular, backstripping the sediment layers requires a well-constrained geological framework. A method is proposed here to investigate the subsidence history of a margin based on forward stratigraphic modelling. Using the Sedflux model, several experiments are done using generally agreed upon assumptions on the parameters describing lithospheric rheology and isostatic behaviour of a margin. The stratigraphic modelling of the Rhône deltaic margin during the last climatic cycle (125 kyr) provides an assessment of these parameter estimates and their influence on geohistory (tectonic/thermal subsidence and sediment loading). The model results confirm the important impact of water loading on vertical deflection along the platform between glacial low sea-level and interglacial high sea-level. Based on Gulf of Lions (NW Mediterranean) observations, a conceptual method that uses the stratigraphic simulations is produced in order to evaluate the different components of the total subsidence of a margin, and, in particular, the relative impact of tectonic subsidence and sediment load.     

Influence of cardiac motion on diffusion-weighted magnetic resonance imaging of the liver

Purpose  

To assess cardiac motion-induced signal loss in diffusion-weighted magnetic resonance imaging (DWI) of the liver using dynamic DWI.     

数字水印的高通块替换攻击

To improve the watermark benchmarks database, a new BRA (Block Replacement Attack) method is introduced in this paper. Unlike the typical BRA which exploits the self similarity among blocks in image, the scheme utilizes the self similarity in various scale and orientation bands in the wavelet domain of the image. They search the replacement blocks from the blocks of the smaller sub image at the next lower resolution. The most important advantage of this scheme is that the pyramid sub band decomposition acts as an automatic block classifier, with the result of simplifying the block search and block matching procedures and thus making the block replacement more effective. Furthermore, an improved algorithm based on Fuzzy set theory is introduced in which the number of blocks chosen for combination are modified adaptively to obtain the candidate replacement blocks. It simplifies the procedure for searching the candidate replacement blocks. These advantages are confirmed by the experimental results, which show that the performance of the scheme is superior to typical BRA methods.     

Step-like all-optical decision function using nonlinear polarisation rotation in a Nonlinear Optical Loop Mirror and in a subsequent fibre section with output polarisation selection

We propose and study numerically a fibre-based scheme designed to generate a step-like optical decision function for ultrafast data processing applications. The setup includes two main sections disposed in series: a Nonlinear Optical Loop Mirror with an output polariser on the one hand, and a circularly birefringent fibre span with a quarter wave retarder at the input and a polariser at the output on the other hand. Both sections operate through nonlinear polarisation rotation, and the switching characteristic is controlled through the light ellipticity, which can be adjusted by setting properly the orientation of the input polarisation, and by rotating the wave retarder and the two polarisers. For proper adjustment of these four parameters, a step-like optical decision function with ～10 dB/dB steepness is predicted. In the frame of all-optical regeneration, the setup allows eliminating ～76% peak-to-peak amplitude fluctuations on the marks and ～30% relative power on the spaces. We believe that this architecture should be considered for the design of ultrafast transmission networks and in the frame of all-optical computing applications.