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101.
Exact rogue wave solutions, including the first-order rogue wave solutions and the second-order ones, are constructed for the system of two coupled nonlinear Schrödinger (NLS) equations with varying potentials and nonlinearities. The method employed in this paper is the similarity transformation, which allows us to map the inhomogeneous coupled NLS equations with variable coefficients into the integrable Manakov system, whose explicit solutions have been well studied before. The result shows that the rogue wavelike solutions obtained by this transformation are controllable. Concretely, we illustrate how to control the trajectories of wave centers and the evolutions of wave peaks, and analyze the dynamic behaviors of the rogue wavelike solutions. 相似文献
102.
103.
Ke Zan Xing-Yun Chai Xiao-Qing Chen Qing Wu Qiang Fu Si-Xiang Zhou Peng-Fei Tu 《Tetrahedron》2012,68(25):5060-5065
A novel dimeric guaianolide with an unprecedented skeleton, named artanomadimer A (1), and five new analogues, artanomadimers B–F (2–6), were isolated from the aerial parts of Artemisia anomala. Their structures and stereochemistry were elucidated by extensive spectroscopic methods, and the absolute stereochemistry of compound 4 was confirmed by X-ray crystallographic analysis. Artanomadimer A (1) is probably formed through a Diels–Alder reaction with the new carbon–carbon bond formation of C-11/C-2′ and C-13/C-5′ based on its structure. A cytotoxic evaluation showed that compounds 1 and 6 exhibited significant inhibitory effects against the cell growth of BGC-823 tumor cell lines with IC50 values of 2.71 and 6.25 μM, respectively. 相似文献
104.
Degradative encryption, a new selective image encryption paradigm, is proposed to encrypt only a small part of image data to make the detail blurred but keep the skeleton discernible. The efficiency is further optimized by combining compression and encryption. A format-compliant degradative encryption algorithm based on set partitioning in hierarchical trees (SPIHT) is then proposed, and the scheme is designed to work in progressive mode for gaining a tradeoff between efficiency and security. Extensive experiments are conducted to evaluate the strength and efficiency of the scheme, and it is found that less than 10% data need to be encrypted for a secure degradation. In security analysis, the scheme is verified to be immune to cryptographic attacks as well as those adversaries utilizing image processing techniques. The scheme can find its wide applications in online try-and-buy service on mobile devices, searchable multimedia encryption in cloud computing, etc. 相似文献
105.
Yan Y Liu Q Wang J Wei J Gao Z Mann T Li Z He Y Zhang M Liu L 《Journal of colloid and interface science》2012,371(1):15-19
A novel single-step approach was developed to prepare large-scale MgAl-LDHs ultrathin nanosheets. The key point of the successful realization was that we employed a high concentration of H(2)O(2). Oxygen molecules, derived from in situ decomposition of H(2)O(2), were speculated to be the decisive factor leading to complete separation of LDHs layers. The ultrathin nanosheets were characterized by XRD, TEM, AFM, FT-IR, and TG-DSC. The results indicated that the thickness of these nanosheets was about 1.44 nm, which was almost in perfect agreement with the theoretical thickness of two LDHs layers. From the TG-DSC curves, the weight loss of these exfoliated MgAl-LDHs ultrathin nanosheets at 500°C was 18.5%, which was much smaller compared to the 32.3% weight loss of unexfoliated MgAl-LDHs. 相似文献
106.
从宏观与微观机制方面探讨了孔隙水压力对岩体脆-延性转变的影响。定义了一个峰后破坏割线模量Epost来表征孔隙水压力对岩体应力应变曲线转型的效应,并结合突变理论得到的斜坡失稳的刚度判据,进一步分析了孔隙水压力对应力应变曲线峰后斜率的影响,随孔隙水压力的增加,峰后曲线斜率变陡,峰后刚度增大,即材料的均匀性、脆性增大与刚度比k减小。因此在系统内部条件不变时,刚度比k=1时就存在一个临界孔隙水压力pwcritical,即降雨等涨落因素引起滑面介质中的孔隙水压力大于这个临界值时斜坡就易于发生突变失稳。从而深化认识了降雨等外部涨落因素对斜坡系统失稳的重要触发作用。 相似文献
107.
ICP-MS测定模拟全血基体中不同质量段的Mg, Cu, Pb元素,考察基体效应对测定值的影响,分别采用传统内标法和单一内标CAIS方法(common analyte internal standardization)对其进行校正和比较。结果表明CAIS方法适用于不同浓度血液基体中多种元素的同时校正,且效果良好,其相对平均误差仅为3.05%,明显低于传统内标法的12.39%和校正前的23.91%;CAIS方法不受内标元素和被测元素质量数差异、测定强度差异以及电极电位差异的限制;使用全血和血清标准物质对CAIS方法可靠性进行验证,测定值全部落在标准值范围内。 相似文献
108.
现今国内外已经有不少对可信平台模块进行测试的研究成果,但是对测试效率分析不足.本文基于自动机理论和中国邮递员问题,提出了可信平台模块改进的有限状态机模型与相应的优化测试方案,通过寻找一条遍历有限状态机模型中每一条转移至少一次的最短路径的方法,从而生成费用优化的测试序列.测试结果表明,测试方案能够简化有限状态机状态的测试. 相似文献
109.
110.