Bit-plane decomposition makes images obtain a number of layers. According to the amount of data information, images are encrypted, and the paper proposes image encryption method with Chaotic Mapping based on multi-lay...Bit-plane decomposition makes images obtain a number of layers. According to the amount of data information, images are encrypted, and the paper proposes image encryption method with Chaotic Mapping based on multi-layer parameter disturbance. The advantage of multi-layer parameter disturbance is that it not only scrambles pixel location of images, but also changes pixel values of images. Bit-plane decomposition can increase the space of key. And using chaotic sequence generated by chaotic system with different complexities to encrypt layers with different information content can save operation time. The simulation experiments show that using chaotic mapping in image encryption method based on multi-layer parameter disturbance can cover plaintext effectively and safely, which makes it achieve ideal encryption effect.展开更多
Using first-principles calculations, we studied the interaction of methanol with the Pt（100） surface based on generalized gradient approximation. We found that top sites of Pt（100） surface are the favored adsorpti...Using first-principles calculations, we studied the interaction of methanol with the Pt（100） surface based on generalized gradient approximation. We found that top sites of Pt（100） surface are the favored adsorptive positions in energy, and methanol molecule interacts with the Pt surface through oxygen atoms. Moreover, we also explored the possible dissociation pathways of methanol on the Pt surface, and suggested that the products of dissociation can be controlled by the external manipulation.展开更多
The first laser excites a molecule to a lower triplet state and another sequential laser excites it resonantly to higher triplet states or makes it ionization. This two-step two-laser method provides a novel way to st...The first laser excites a molecule to a lower triplet state and another sequential laser excites it resonantly to higher triplet states or makes it ionization. This two-step two-laser method provides a novel way to study the electron transfer or charge transfer of excited molecules. The higher excited benzophenone and its radical cation can be observed under the time-resolved absorption method when it was excited to lower triplet state by one laser and another one exciting it to higher triplet states resonantly. The higher excited benzophenone molecules undergoing inter-molecular hydrogen abstraction with iso-propylalcohol molecules are faster than the lower ones.展开更多
文摘Bit-plane decomposition makes images obtain a number of layers. According to the amount of data information, images are encrypted, and the paper proposes image encryption method with Chaotic Mapping based on multi-layer parameter disturbance. The advantage of multi-layer parameter disturbance is that it not only scrambles pixel location of images, but also changes pixel values of images. Bit-plane decomposition can increase the space of key. And using chaotic sequence generated by chaotic system with different complexities to encrypt layers with different information content can save operation time. The simulation experiments show that using chaotic mapping in image encryption method based on multi-layer parameter disturbance can cover plaintext effectively and safely, which makes it achieve ideal encryption effect.
文摘Using first-principles calculations, we studied the interaction of methanol with the Pt（100） surface based on generalized gradient approximation. We found that top sites of Pt（100） surface are the favored adsorptive positions in energy, and methanol molecule interacts with the Pt surface through oxygen atoms. Moreover, we also explored the possible dissociation pathways of methanol on the Pt surface, and suggested that the products of dissociation can be controlled by the external manipulation.
基金the National Natural Science Foundation of China (Grant No. 20073059).
文摘The first laser excites a molecule to a lower triplet state and another sequential laser excites it resonantly to higher triplet states or makes it ionization. This two-step two-laser method provides a novel way to study the electron transfer or charge transfer of excited molecules. The higher excited benzophenone and its radical cation can be observed under the time-resolved absorption method when it was excited to lower triplet state by one laser and another one exciting it to higher triplet states resonantly. The higher excited benzophenone molecules undergoing inter-molecular hydrogen abstraction with iso-propylalcohol molecules are faster than the lower ones.
