一种包含非线性光学效应的硅基微环稳态模型

微环谐振器是集成光学中的关键器件,它的实际滤波特性会受到输入光功率的影响,但长期以来,微环谐振器的稳态模型仅包含线性光学作用。考虑微环谐振器反馈波导中的光学非线性引入的损耗和相移,以及微环耦合器中光学非线性引入的耦合比改变等因素,推导了考虑自相位调制、双光子吸收和热光效应的微环谐振器的非线性模型。重点讨论了双光子吸收和光学非线性引入的耦合器耦合比改变对微环谐振器陷波深度的影响,仿真结果表明,在热光效应和自相位调制产生谐振谱线频移的同时,功率相关的耦合器耦合比的改变对微环谐振器陷波深度的影响较大。     

Competition between Dispersion and Absorption of Doubly-Dressed Four-Wave Mixing and Dressed Six-Wave Mixing

We study the competition between dispersion and absorption of doubly-dressed four-wave mixing （DDFWM） and dressed six-wave mixing. In the case of weak coupling fields limit, we find DDFWM signal is affected by destructive interference between four-wave mixing（FWM） and six-wave mixing as wen as constructive interference between FWM and eight-wave mixing. By analysing the difference between two kinds of doubly dressing mechanisms （parallel cascade and nested cascade） in this opening five-level system, we can further understand the generated high-order nonlinear optical signal dressed by multi-fields.     

Half-Lives of Superheavy Nuclei in Z=113 Alpha Decay Chain

The generalized liquid drop model （GLDM）, including the proximity effects and centrifugal potential, and the cluster model with Cosh potential are used to study the half-lives of some Z = 113 isotopes and their α-decay products. The experimental half-lives of 284^113, 283^113, 282^113 and their α-decay products are well reproduced by the two models when zero angular momenta transfer is assumed. For 278^113 and its α-decay products, both the GLDM and the duster model could provide satisfactory results if we assume the α particle carry five units of angular momenta, which indicates that possible nonzero angular momenta transfer and need further experimental measurements with high precision. Finally, we show that half-lives of α-decay are quite sensitive to the angular momentum transfers, and a formula could be used to describe the correlation between α-decay half-life and angular momentum transfer successfully.     

无皂种子分散聚合法制备单分散双重响应性微凝胶

以N-异丙基丙烯酰胺及2-乙烯基吡啶为主要单体, 采用无皂种子分散聚合法制备了单分散的、具有温度及pH双重响应性能的核-壳结构微凝胶, 并以扫描电镜及动态激光光散射等手段对微凝胶粒子的结构和性能进行了研究. 溶胀行为研究表明, 微凝胶粒子具有独立的互不干扰的温度及pH敏感性能, 其体积相变温度与纯聚N-异丙基丙烯酰胺(PNIPAM)凝胶基本一致, 说明局部分布的弱电离单体不会对PNIPAM凝胶的体积相变温度造成影响.     

准二维无定形碳结构的制备和结构表征

从单层和少层的石墨烯出发,利用透射电子显微镜中的高能电子束辐照,可控地制备了准二维完全无定形和半无定形碳结构.用高分辨成像和相干的纳米区域电子衍射技术表征了样品结构在高能电子束辐照前后的变化.基于实验记录的电子衍射花样得到了样品的原子对分布函数.分析表明,在所制备的准二维无定形结构中,六元环不再是碳原子的主要排列方式,碳原子的各阶最近邻间距相对于完美石墨烯中的值有所偏离并趋向无序;同时还发现,锯齿型的碳链结构不易被破坏,并使得准二维无定形碳结构中还保留了短程有序和可达0.5nm的中程有序.     

化学键合多孔聚合物小球气相色谱固定相

以大孔聚苯乙烯-二乙烯苯为基质,制备了两个系列化学键合聚乙二醇和脂肪醚聚合物小球固定相。色谱性能评价表明,它们的极性随含氧量增加而增加;从对于醇混合物及苯-环已烯-环已烷的分离实例说明,与基质相比,键合小球不仅有较高选择性,而且柱温较低,或保留时间较短,这与前人键合小分子官能团的改性方法比较是一个明显进步。     

包覆聚合物高效液相色谱柱填料的研究进展

评述了用于高效液相色谱的包覆聚合物填料的研究进展．该类填料以无机载体为基质，包覆以多种有机聚合物层．这些新型填料既保留了有机聚合物和无机基质的优点，又克服了它们各自的缺陷．包覆的聚合物类型包括聚烃、聚醚、聚酰胺、多糖、多肽、聚硅氧烷、聚胺及多核苷酸等，无机基质包括硅胶、铝胶、钛胶、钻胶及多孔石墨化碳等．包覆聚合物固定相可用于几乎所有色谱方式，如反相高效液相色谱、高效离子交换色谱、手性固定相、超临界流体色谱、体积－排阻色谱，以及亲合色谱．     

从一道竞赛题谈周期数列的有关问题

1985年第三届美国数学邀请赛(AIME)试题第五题是: 选取一列整数a_1,a_2,a_3,……,使得每个n≥3都有a_2=a_(n-1)-a_(n-2),若该数列的前1492项之和等于1985,而前1985项之和等于1492,那么前2001项之和是多少? 原参考答案根据关系式a_n=a_(n-1)-a_(n-2)所暗示的递推规律给出了一个探索性解答,这里将通过求通项公式的办法进行解答;并在此基础上得出两个一般性公式。解:∵ a_n=a_(n-1)-a_(n-2), ∴ a_n-a_(-1)+a_(-2)=0 易知此递推式乃二阶齐次线性递归方程,解相应的特征方程x~2 -x+1=0得:     

羟基磷灰石中氢键的XPS考察

Several calcium orthophosphates (tricalcium phosphate, monocalcium dihydropho-sphate, dicalcium hydrophosphate, and hydroxyapatite) are characterized by XPS and IR method. The P2p electron binding energies follow the order Ca(H_2PO_4)_2>CaHPO_4>Ca_(10)(OH)_2(PO_4)_6>Ca_3(PO_4)_2. It is expounded that there is hydrogen bonding of (OH...OPO_3) between the OH~- ion and the neighbour oxygen of the phosphate in hydroxyapatite.