A Robust Blind Watermarking Algorithm Based on Non-Subsampled Contourlet Transform and Human Visual System

提出一种基于无下采样COnTOurlET变换(nSCT)和人眼视觉系统(HVS)的自适应稳健盲数字水印方案,该方案在nSCT域中对人类视觉系统的特性进行建模,利用人眼的视觉掩盖机制自适应嵌入水印序列。实验结果表明,该数字水印方案在保证人眼视觉不可见性的前提下,对包括噪声、JPEg压缩、图像剪切、滤波、图像扭曲等均具有很强的稳健性,并且检测水印时无需原始图像,是一种很有前途的盲水印方案。A robust blind digital watermarking scheme based on non-subsampled contourlet transform(NSCT) and human visual system(HVS) was proposed.In this paper,we establish a model of the human visual system in NSCT domain,using visual masking effect of HVS to adaptive embed watermark sequences.The experimental results show that the digital watermark not only the transparency can be guaranteed,but also has good robustness to noise addition,JPEG compression,cropping,filtering and image twisting etc.Furthermore,the watermark can be detected without original image.This is a perspective blind watermarking scheme.国家自然科学基金(30900328);福建省自然科学基金(2008J0032;2009J01301;2009J01302);厦门大学985二期信息创新平台(0000X07204);厦门市科技计划高校创新项目(3502Z20083006)资助课

An Entrant of Smaller Fullerene: C-56 Captured by Chlorines and Aligned in Linear Chains

A smaller fullerene C-56 (#913) is stabilized, isolated, and crystallographically characterized as C56Cl10. The geometric parameters of C56Cl10 imply the otherwise unstable cage of C-56 can be stabilized by chlorination through releasing its surface strains and maintaining fragmental aromaticity. An unexpected C Cl center dot center dot center dot Cl C short contact, as well as the linear alignment with pearl - necklace-shaped, is revealed in C56Cl10 crystal.NSFC,20525103,20531050,20721001,20425312, 20423002 973 Program,2007C13815301

Chlorofullerenes featuring triple sequentially fused pentagons

通讯作者地址: Tan,YZ(通讯作者),Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 2. Xiamen Univ, Coll Chem & Chem Engn, Dept Chem, Xiamen 361005, Peoples R China 电子邮件地址: [email protected], [email protected] triple sequentially fused pentagons (TSFP) motif is one of the basic subunits that could be used for constructing fullerenes, but it violates the isolated pentagon rule (IPR) and has not been found in carbon cages to date. The properties of TSFP-incorporating fullerenes are thus poorly explored both theoretically and experimentally. Reported herein are four chlorinated derivatives of three different fullerene cages, all with the TSFP motif. X-ray crystallographic analyses indicate that the molecular strain inherent to the pentagon adjacency of a TSFP is significantly relieved upon exohedral chlorination, leaving one of the four pentagon fusion sites unsaturated and rendering the present derivatives chiral. This unique reactivity, in stark contrast to that of previously reported non-IPR fullerenes containing double fused pentagons or triple directly fused pentagons, can be rationalized by density functional theory calculations, and are expected to stimulate further studies of these new members of the fullerene family, both theoretically and experimentally.NNSF of China 20525103,20531050,20721001,20423002 20673088 973 Program 2007CB81530

Two I-h-symmetry-breaking C-60 isomers stabilized by chlorination

通讯作者地址: Xie, SY (通讯作者), Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 2. Xiamen Univ, Dept Chem, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 电子邮件地址: [email protected] abiding surprise in fullerene science is that I-h-symmetric buckminsterfullerene C-60 (ref. 1) (I-h-C-60 or C-#1,812(60), the nomenclature specified by symmetry or by Fowler's spiral algorithm(2)) remains the sole C-60 species experimentally available. Setting it apart from the other 1,811 topological isomers (isobuckminsterfullerenes) is its exclusive conformity with the isolated-pentagon rule(3), which states that stable fullerenes have isolated pentagons. Although gas-phase existence of isobuckminsterfullerenes has long been suspected(4-7), synthetic efforts have yet to yield successful results. Here, we report the realization of two isobuckminsterfullerenes by means of chlorination of the respective C-2v-and C-s-symmetric C-60 cages. These chlorinated species, (C60Cl8)-C-#1,809(1) and (C60Cl12)-C-#1,804(2), were isolated in experimentally useful yields. Structural characterization by crystallography unambiguously established the unique pentagon-pentagon ring fusions. These distinct structural features are directly responsible for the regioselectivity observed in subsequent substitution of chlorines, and also render these unprecedented derivatives of C60 isomers important for resolving the long-standing puzzle of fullerene formation by the Stone-Wales transformation scheme(8-11).NNSF of China,20525103 ,20531050 ,20721001 , 20571062 ,20425312 973 Program 2007CB81530