生长温度对磁控溅射ZnO薄膜的结晶特性和光学性能的影响

采用反应射频磁控溅射方法，在Si (100) 基片上制备了具有高c轴择优取向的ZnO薄膜.利用 原子力显微镜、透射电子显微镜、X射线衍射分析、拉曼光谱等表征技术，研究了沉积温度 对ZnO薄膜的表面形貌、晶粒尺度、应力状态等结晶性能的影响；通过沉积温度对透射光谱 和光致荧光光谱的影响，探讨了ZnO薄膜的结晶特性与光学性能之间的关系.研究结果显示， 在室温至500℃的范围内，ZnO薄膜的晶粒尺寸随沉积温度的增加而增加，在沉积温度为500 ℃时达到最大；当沉积温度为750℃时，ZnO薄膜的晶粒尺度有所减小；在室温至750℃的范 围内，薄膜中ZnO晶粒与Si基体之间均存在着相对固定的外延关系；在沉积温度低于500℃时 ，制备的ZnO薄膜处于压应变状态，而750℃时沉积的薄膜表现为张应变状态.沉积温度的不 同导致ZnO薄膜的折射率、消光系数、光学禁带宽度以及光致荧光特性的变化，沉积温度对 紫外光致荧光特性起着决定性的作用.此外，探讨了影响薄膜近紫外光致荧光发射的可能因 素. 关键词： ZnO薄膜 表面形貌 微观结构 光学常数     

在SQUID心磁测量中基于奇异值分解和自适应滤波的噪声消除法

采用矩阵奇异值分解(singular value decomposition, SVD)的方法，对高温射频超导量子干涉仪(HTc rf-SQUID)采集到的单通道心磁信号进行处理.证明了对于近似周期性的心磁信号，在无参考噪声的情况下矩阵奇异值分解的方法与自适应窄带陷波相结合有较好的消除广谱噪声的效果. 关键词： 高温射频超导量子干涉仪 心磁信号 奇异值分解 噪声消除     

正相协列乘积和的重对数律与强大数律

证明了强平稳正相协列乘积和的重对数律与不同分布正相协列乘积和的强大数律,指出了部分和服从强大数律但乘积和未必服从强大数律这一事实,并讨论了定理2中一个条件的必要性．     

具常数特征拟线性双曲型方程组Cauchy问题

考虑具常数特征拟线性双曲型方程,提出一个新的可化约方程组的方法,证明了具常特征方程组Cauchy问题经典解的整体存在性定理.同时构造一些例子说明一些有趣的现象.     

Preparation, characterization and photocatalytic activity of polycrystalline Bi2O3/SrTiO3 composite powders

Bi₂O₃/SrTiO₃ composite powders have been prepared and their photocatalytic activities were investigated by photooxidation of methanol. These powders were characterized by UV-Visible diffuse reflectance spectra, SEM and X-ray diffraction (XRD). The results revealed that all the Bi₂O₃/SrTiO₃ composite powders exhibited higher photocatalytic activity than pure SrTiO₃, Bi₂O₃ and TiO₂ (P25) under visible light irradiation (λ>440 nm). The effects of the Bi₂O₃ contents on the photocatalytic activities of the composite powders were examined, the photocatalytic activities increased with the content of Bi₂O₃ increasing to a maximum of 83% and then decreased under visible light irradiation. The effects of the calcination temperatures on the photocatalytic activities of the composite powders were also investigated.     

Influence of focusing depth on the microfabrication of waveguides inside silica glass by femtosecond laser direct writing

We studied the influence of focusing depth on the index change threshold and damage threshold of silica glass irradiated by a focused 120 fs laser beam. Both thresholds increased with the focusing depth. The aspect ratio of the waveguide cross section can be selected by changing the focusing depth. A 5 mm long waveguide was written at the depth of 2100 μm, which was single mode at 632.8 nm and exhibited propagation loss of 0.56 dB/cm. The refractive index change was calculated to be ∼2.47×10^-3. The influence of the focusing depth should be considered in multi-layer devices as shown in the fabrication of a 3×3 waveguide array. PACS 42.62.-b; 42.82.Et; 81.05.Kf     

A Genus-3 Topological Recursion Relation

In this paper, we give a new genus-3 topological recursion relation for Gromov-Witten invariants of compact symplectic manifolds. This formula also applies to intersection numbers on moduli spaces of spin curves. A by-product of the proof of this formula is a new relation in the tautological ring of the moduli space of 1-pointed genus-3 stable curves. Research of the first author was partially supported by NSF grant DMS-0204824 Research of the second author was partially supported by NSF grant DMS-0505835     

Stowage planning in maritime container transportation

We consider a stowage-planning problem of arranging containers on a container ship in the maritime transportation system. Since containers are accessible only from the top of the stack, temporary unloading and reloading of containers, called shifting, is unavoidable if a container required to be unloaded at the current port is stacked under containers to be unloaded at later ports on the route of the ship. The objective of the stowage planning problem is to minimize the time required for shifting and crane movements on a tour of a container ship while maintaining the stability of the ship. For the problem, we develop a heuristic solution method in which the problem is divided into two subproblems, one for assigning container groups into the holds and one for determining a loading pattern of containers assigned to each hold. The former subproblem is solved by a greedy heuristic based on the transportation simplex method, while the latter is solved by a tree search method. These two subproblems are solved iteratively using information obtained from solutions of each other. To see the performance of the suggested algorithm, computational tests are performed on problem instances generated based on information obtained from an ocean container liner. Results show that the suggested algorithm works better than existing algorithms.     

脑细胞激活素药物的化学成分分析

采用日本岛津LC-60A型高压液相色谱仪和美国P-E3030型原子吸收分光光度计，对该药进行了氨基酸、维生素和化学元素的含量测定。结果表明，该药含有18种氨基酸，不少于3种维生素和20几种化学元素，为进一步改进该药物的合理配制方法和临床应用提供了参考数据。