A blind watermarking algorithm resisting to geometric transforms based on SVD

A new watermarking algorithm resisting to geometric transformation based on singular value decomposition(SVD) in logarithm polar coordinate is proposed.The log-polar mapping(LPM) is used to resist rotation and scaling attacks,and the odd-even quantization algorithm is used to embed watermark so it can be extracted without the original host image.The experiments show that the proposed algorithm not only resists various geometric attacks but also is robust enough to the common signal processing.     

Phase field simulation of the 180° domain-switching process in PbTiO<Subscript>3</Subscript> single crystal under an antiparallel electric field

The process of 180° domain switching in PbTiO₃ single crystal under an antiparallel electric field was investigated by the three-dimensional phase field simulation, especially the effect of electric field on the type and duration of domain switching. It is found that the polarization reversal of domains takes place under an antiparallel electric field in PbTiO₃ single crystal. The results of the phase field simulation indicate that there is only 90° domain switching under a weak electric field. With the rise of the electric field, 180° domain switching appears. If the electric field is strengthened further, 90° domain switching disappears and the duration of domain switching is shortened.     

A novel data embedding method for H.264 stereo video codec with joint prediction scheme

It is important to reduce data redundancy of stereo video in practical applications. In this paper,first,a data embedding method for stereo video(DEMSV) is investigated by embedding the encoding data into the reference frame to encode stereo video. It can use only one channel to transfer all the video data and the receiver can choose a monocular video decoder or stereo video decoder adaptively. Then,introducing the joint prediction scheme in the coding process of DEMSV,we propose a novel data embedding meth...     

Controllable stereoselective synthesis of pyrano[3,2-<Emphasis Type="Italic">c</Emphasis>]quinolines by lanthanide halides catalyzed aza-Diels-Alder reactions

An efficient method for the synthesis of tetrahydroquinoline derivatives via lanthanide halides catalyzed domino reactions of arylamines with dihydropyran is described. Either the cis or the trans isomer can be obtained as the major product in good yield by changing the catalyst and reaction conditions.     

方正智绘Mirage的特点及应用

文章介绍了方正智绘Mirage的技术特点及其制作与应用。     

Giulio Racah and theoretical physics in Jerusalem

The present article considers Giulio Racah’s contributions to general physical theory and his establishment of theoretical physics as a discipline in Israel. Racah developed mathematical methods that are based on tensor operators and continuous groups. These methods revolutionized spectroscopy. Currently, these are essential research tools in atomic, nuclear and elementary particle physics. He himself applied them to modernizing theoretical atomic spectroscopy. Racah laid the foundations of theoretical physics in Israel. He educated several generations of Israeli physicists, and put Israel on the world map of physics.     

An organic junction between the vein and membrane of the dragonfly wing

A dragonfly wing consists of membranes and both longitudinal and cross veins. We observed the microstructure cross-section at several locations in the dragonfly wing using environmental scanning electron microscopy (ESEM). The organic nature of the junction between the vein and the membrane was clearly identifiable. The membrane was divided into two layers, the upper epidermis and the lower epidermis. These layers extend around the sandwich structure vein, and combine with the adjacent membrane at a symmetrical location along the vein. Thus, we defined this as an organic junction between the vein and the membranes. The organic junction is able to form a tight corrugation angle, which dramatically increases both the warping rigidity and the strength of the wing, but not the torsional rigidity. The torsional deformation is primarily controlled by the microstructure of the longitudinal veins, and is based on the relative rotation angle between the epidermal layer and the inner layer of the vein that forms the zigzag section.     

HCN2 channels in local inhibitory interneurons constrain LTP in the hippocampal direct perforant path

Neuronal hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are known to modulate spontaneous activity, resting membrane potential, input resistance, afterpotential, rebound activity, and dendritic integration. To evaluate the role of HCN2 for hippocampal synaptic plasticity, we recorded long-term potentiation (LTP) in the direct perforant path (PP) to CA1 pyramidal cells. LTP was enhanced in mice carrying a global deletion of the channel (HCN2^−/−) but not in a pyramidal neuron-restricted knockout. This precludes an influence of HCN2 located in postsynaptic pyramidal neurons. Additionally, the selective HCN blocker zatebradine reduced the activity of oriens-lacunosum moleculare interneurons in wild-type but not HCN2^−/− mice and decreased the frequency of spontaneous inhibitory currents in postsynaptic CA1 pyramidal cells. Finally, we found amplified LTP in the PP of mice carrying an interneuron-specific deletion of HCN2. We conclude that HCN2 channels in inhibitory interneurons modulate synaptic plasticity in the PP by facilitating the GABAergic output onto pyramidal neurons.