针对现有保序加密(order-preserving encryption,OPE)方案中客户端与服务端多轮交互导致的较大通信开销问题,提出一种基于本地临时缓存表和自平衡二叉搜索树的保序加密方案。在数据插入阶段通过客户端临时缓存表对插入数据预处理确定初...针对现有保序加密(order-preserving encryption,OPE)方案中客户端与服务端多轮交互导致的较大通信开销问题,提出一种基于本地临时缓存表和自平衡二叉搜索树的保序加密方案。在数据插入阶段通过客户端临时缓存表对插入数据预处理确定初始交互节点,避免从根节点开始交互,降低算法的通信开销;并使用平衡因子为k的AVL(Adelson-Velsky and Landis)树作为编码树,避免频繁的编码更新带来的较大计算开销。此外,采用格式保留加密算法FF1-SM4对数据进行加密,不仅能够提高存储效率,而且无需对数据库表结构进行大幅修改,也无需对应用程序进行修改以适应密文的变化。实验结果表明,当插入5000条数据时,该方案相较gmOPE加密效率提升约13.91%,单次插入的平均交互次数下降约69.81%。展开更多
The dot products mu(g)beta(CT) of first hyperpolarizability and ground state dipole moment of two merocarbocyanines were measured experimentally with solvatochromism and compared to the values obtained by AM1/FF calcu...The dot products mu(g)beta(CT) of first hyperpolarizability and ground state dipole moment of two merocarbocyanines were measured experimentally with solvatochromism and compared to the values obtained by AM1/FF calculation. The comparable result was also obtained by the measurement of second harmonic generation (SHG) for LB film of dye II. The mu(g)beta(CT) of dye II is larger than that of the well known NLO chromophore 4-N, N-dimethylamino-4'-nitrostilbene (DANS).展开更多
Novel low dipole moment (μ) and large first hyperpolarizability (β) electrooptic chromophores have been designed based on the special characteristic of reversed dipole moment in the excited state of exocyclic double...Novel low dipole moment (μ) and large first hyperpolarizability (β) electrooptic chromophores have been designed based on the special characteristic of reversed dipole moment in the excited state of exocyclic double bond (ECDB) conjugated bridge by the optimization of the substituted method, and their electronic and second-order nonlinear optical properties have been theoretically investigated by employing the AM1/FF and ZINDO/S-CI approaches. By extending the conjugation length and optimizing the donor/acceptor strength, the oscillator strength of the excited transition that contributes to the molecular nonlinearity can be further enhanced. The designed chromophores possess a larger figure of merit (FOM) than that of 4-N,N-dimethylamino-4’-nitrostilbene (DANS), and lower (5 D) ground state dipole moment.Novel low dipole moment (μ) and large first hyperpolarizability (β) electrooptic chromophores have been designed based on the special characteristic of reversed dipole moment in the excited state展开更多
文摘针对现有保序加密(order-preserving encryption,OPE)方案中客户端与服务端多轮交互导致的较大通信开销问题,提出一种基于本地临时缓存表和自平衡二叉搜索树的保序加密方案。在数据插入阶段通过客户端临时缓存表对插入数据预处理确定初始交互节点,避免从根节点开始交互,降低算法的通信开销;并使用平衡因子为k的AVL(Adelson-Velsky and Landis)树作为编码树,避免频繁的编码更新带来的较大计算开销。此外,采用格式保留加密算法FF1-SM4对数据进行加密,不仅能够提高存储效率,而且无需对数据库表结构进行大幅修改,也无需对应用程序进行修改以适应密文的变化。实验结果表明,当插入5000条数据时,该方案相较gmOPE加密效率提升约13.91%,单次插入的平均交互次数下降约69.81%。
文摘The dot products mu(g)beta(CT) of first hyperpolarizability and ground state dipole moment of two merocarbocyanines were measured experimentally with solvatochromism and compared to the values obtained by AM1/FF calculation. The comparable result was also obtained by the measurement of second harmonic generation (SHG) for LB film of dye II. The mu(g)beta(CT) of dye II is larger than that of the well known NLO chromophore 4-N, N-dimethylamino-4'-nitrostilbene (DANS).
基金This work was supported by the National Natural Science Foundation of China (Grant Nos. 59790050, 29704009 and 59973024).
文摘Novel low dipole moment (μ) and large first hyperpolarizability (β) electrooptic chromophores have been designed based on the special characteristic of reversed dipole moment in the excited state of exocyclic double bond (ECDB) conjugated bridge by the optimization of the substituted method, and their electronic and second-order nonlinear optical properties have been theoretically investigated by employing the AM1/FF and ZINDO/S-CI approaches. By extending the conjugation length and optimizing the donor/acceptor strength, the oscillator strength of the excited transition that contributes to the molecular nonlinearity can be further enhanced. The designed chromophores possess a larger figure of merit (FOM) than that of 4-N,N-dimethylamino-4’-nitrostilbene (DANS), and lower (5 D) ground state dipole moment.Novel low dipole moment (μ) and large first hyperpolarizability (β) electrooptic chromophores have been designed based on the special characteristic of reversed dipole moment in the excited state
