Realization of quantum discrete Fourier transform with NMR

The pulse sequences of the logic operations used in quantum discrete Fourier transform are designed for the experiment of nuclear magnetic resonance(NMR), and 2-qubit discrete Fourier transforms are implemented experimentally with NMR. The experimental errors are examined and methods for reducing the errors are proposed.     

流媒体传输中的软件解码技术应用研究

通过对流媒体传输过程中的音视频数据的软解压技术研究,结合校园网络教学系统,设计开发了基于Windows CE系统下的嵌入式流媒体播放器解码器,实现了软解压技术在网络教学中的应用.     

机器翻译中的一种状态空间搜索方法

在机器翻译中出现一类相关对象组合．将这些组合与规则匹配时,因出现“组合爆炸”使搜索失败．提出一种递阶智能搜索方法,根据先验知识先用闭环消除法消去对象中不满足相关约束条件的数据,再采用简单的顺序搜索就可以获得问题解．该方法避免了回溯,显著地减少了时间和空间上的开销．     

Loop代数的泛中心扩张

作者主要研究了toroidal李代数,证明了两个主要结果:第一个是任意一个n-toroidal李代数是d-toroidal李代数的n-d个变元的罗朗多项式代数的loop扩张的泛中心扩张,其中1≤d＜n是正整数;第二个是toroidal李代数的任意非零理想和Cantan子代数与泛中心之和的交也非零.作为一个推论,作者得到如果toroidal李代数到另一个李代数有同态且限制在Cartan子代数与泛中心扩张之和上是单射,那么这个同态本身也是单射.     

α-羰基烯酮二硫代缩醛化学研究进展(Ⅰ)

综述了９０年代以来有关α－羰基烯酮二硫代缩醛类化合物的最新进展,限于篇幅,首先对其制备及结构特征做出总结．     

关于集上变换及映射的左、右逆元个数的注记

通过 3个命题给出集上变换幺半群的元素的左逆和右逆的个数及任意一个映射的左、右逆映射的个数 .     

Synergetic enhancement of photoconductivity in oxotitanium phthalocyanine nanocrystalline/fluoronone-based azo/BAH composite photoreceptors

A simple method of liquid phase direct precipitation (LPDP) is employed to prepare oxotitanium phthalocyanine (TiOPc) nanoparticles. By encapsulation within casein coating, the TiOPc nanoparticles exhibit uniform and well-controlled particle sizes. The results of photoinduced discharge experiment demonstrates that the photoconductivity of the photoreceptors fabricated with TiOPc nanoparticles and fluoronone-based azo pigments as composite carrier generation materials was substantially enhanced. The photosensitivity has been improved three times as the TiOPc particle size decreased from 100 nm to 40 nm.     

Spin correlations in the electron-doped high-transition-temperature superconductor Nd2-xCexCuO4+/-delta

High-transition-temperature (high-T(c)) superconductivity develops near antiferromagnetic phases, and it is possible that magnetic excitations contribute to the superconducting pairing mechanism. To assess the role of antiferromagnetism, it is essential to understand the doping and temperature dependence of the two-dimensional antiferromagnetic spin correlations. The phase diagram is asymmetric with respect to electron and hole doping, and for the comparatively less-studied electron-doped materials, the antiferromagnetic phase extends much further with doping and appears to overlap with the superconducting phase. The archetypal electron-doped compound Nd2-xCexCuO4+/-delta (NCCO) shows bulk superconductivity above x approximately 0.13 (refs 3, 4), while evidence for antiferromagnetic order has been found up to x approximately 0.17 (refs 2, 5, 6). Here we report inelastic magnetic neutron-scattering measurements that point to the distinct possibility that genuine long-range antiferromagnetism and superconductivity do not coexist. The data reveal a magnetic quantum critical point where superconductivity first appears, consistent with an exotic quantum phase transition between the two phases. We also demonstrate that the pseudogap phenomenon in the electron-doped materials, which is associated with pronounced charge anomalies, arises from a build-up of spin correlations, in agreement with recent theoretical proposals.     

圆柱分层煤质中并知格林函数的快速计算

提出了一种适于在PC机上计算圆柱分层煤质中和林函数的数值方法，运用迭代方法和渐近方法分区域计算了复宗量圆柱组合函数，得到了谱域和式函数的精确度，用高精度的数值积分法将谱域格林函数经逆傅里叶变换，求得出了格林函数的空域结构，计算结果与现有文献比较，取得了良好的一致性，证明了数值模型的正确性和精确性。     

Synergetic enhancement of photoconductivity in chlorodiane blue /oxotitanylphthalocyanine composites

The nonlinear enhancement of photosensitivity in chlorodiane blue azo (CBA)/ oxotitanylphthalocyanine composites (TiOPc) has been found. Neither evident electronic interaction nor interpenetration between chlorodiane blue and TiOPc molecules is indicated by electronic spectra and X-ray diffraction patterns. Xerographic discharge experiments suggest that the synergetic enhancement of photosensitivity results from contribution of the transition of gap states, which are induced by photoexcitation upon composite photoreceptors. Electron Spin Resonance (ESR) and X-ray Photoelectron Spectroscopy (XPS) data imply that oriented partial charge transfer between TiOPc and CBA molecules occurs when the composites are excited by incident light. This synergetic effect observed in the composite systems with weak electron donor and acceptor provides a novel strategy to design high quality photoconductive materials and devices.