Atomic force microscopic observation on substructure of pollen exine inCedrus deodara andMetasequoia glyptostroboides

The substructure of pollen exine inCedrus deodara (Roxb.) Loud. andMetasequoia glyptostroboides Hu et Cheng has been examined with an atomic force microscope (AFM). The results indicate that the exine substructure units containing sporopollenin in two species are similar in shape, which are granular, but slightly different in size. InCedrus the substructure unit of pollen exine appears to be 56–99 nm long and 42–74 nm wide, while inMetasequoia it appears to be 81–118 nm long and 43–98 nm wide. It has been observed that the subunits of pollen exine inCedrus arranged tightly to form short-rod-like or spheroidal pollen exine units, several or more than ten of which formed an island-like structure. There are various spaces among these island-like structures which are interconnected to occupy the entire pollen exine. InMetasequoia, the subunits of pollen exine also arranged tightly with a distribution tendency of cluster of 3–10, however, no obvious boundary exists among these clusters. From our results, it is concluded that there is no tendency of helical arrangement for the subunits of pollen exine inCedrus andMetasequoia, and the results support Southworth’ view that subunits of pollen exine are granular shape in lattice structure.     

蠕变损伤的随机模糊分析

在考虑材质劣化和空洞损伤的蠕变损伤模型基础上 ,建立蠕变损伤的失效概率模型。通过进一步对蠕变损伤模糊性的讨论 ,提出了蠕变损伤的模糊失效概率模型。算例表明 ,考虑模糊因素是必要的。最后讨论了随机变量的分布情况 ,得到了一些有益的结论     

Determination of the critical nucleation frequency in undercooled metal melt

By studying the effect of thermodynamic and kinetic factors on the nucleation frequency of under cooled metals, the expressions for heterogeneous and homogenous critical nucleation frequencies have been established. The results show that the homogenous critical nucleation frequency per unit volume is directly proportional to the ratio of the cooling rate to the volume of liquid metal. As the value of the equilibrium contact angle function f(θ) of the most effective catalyst is constant, the heterogeneous critical nucleation frequency per unit area of the catalyst surface is di rectly proportional to the ratio of the cooling rate to the sum of the surface area of the most effective catalyst surface ( Rc/ VSv). When Rc/VSv is constant, the heterogeneous critical nucleation frequency per unit area of the catalyst surface is inversely proportional to f(θ)0.53; the critical nucleation frequency per unit continuous mass of the metal melt for both the homogenous and heterogeneous nucleation can be expressed in terms of a general formula. The critical nucleation fre quency is slightly influenced by the nature of the metal. The obtained theoretical result agrees well with the homogenous critical nucleation frequency estimated by Turnbull.     

血清中盐酸洛美沙星的测定及荧光光谱特性

用荧光分光光度法研究了盐酸洛美沙星在血清中的荧光光谱特性,并对其在血清样品中的含量进行了测定．用乙腈沉淀蛋白对血清进行预处理,在硼酸盐缓冲溶液中,用硫酸调节酸度,并使其pH值为3．0,以β环糊精为荧光增敏剂．通过扫描其激发光谱和发射光谱,可知盐酸洛美沙星在血清中有以下荧光特性盐酸洛美沙星血清提取液和盐酸洛美沙星的标准溶液具有相同特征的激发光谱和发射光谱,其激发波长为288nm,发射波长为450nm,也即药物光谱不受血清成分干扰,但血清样品对盐酸洛美沙星的荧光强度造成强烈的荧光猝灭．测定血清中盐酸洛美沙星的线性范围为0．v5～5．0μg·ml,其回归方程为y＝-0．2370+4．809X(R＝0．9968),血清中盐酸洛美沙星的平均回收率为99．5％,方法的相对标准偏差为0．82％(n＝5)．     

小垂度柔索非线性随机响应分析

基于小垂度柔索非线性动力分析模型,研究了平面窄带随机激励下小垂度柔索非线性动态响应,使用等效线性化技术与单模态近似得到响应的均方误差方程,研究表明激励的带宽为激励强度的增函数;当激励的中心频率在指定的范围内,并且激励的带宽小于带宽的临界值时,响应为三值响应。     

电致发光有机薄膜中载流子的输运

研究电致发光有机薄膜中载流子的输运过程,迁移率是描述输运过程的关键物理量。根据载流子在格点间跳跃（hopping)输运理论,提出了一个有机薄膜中载流子输运的理论模型,推导出了迁移率的理论公式,以聚对苯乙炔（poly(p-phenylene vinylene)为例,数值计算了其在不同温度和电场下的迁移率,与实验符合得很好。     

一类拟非扩张算子的不动点定理

讨论了一类非线性拟非扩张算子——M型拟非扩张算子的不动点的存在性，给出了这类算子在满足一定条件下的不动点定理，该定理推广了B．E.Rhodes的结果。     

基于Patran环境的框架结构参数化有限元分析

MSC PATRAN软件只需输入必要的设计参数,就可以自动完成所开发产品的有限元分析.对一实际的框架结构实现了参数化有限元计算模型的建立以及约束和载荷的自动施加, 从而实现了某框架结构的自动化静力有限元分析.开发的参数化设计软件系统具有弹出式菜单风格,便于设计人员使用.通过实际工程实例的计算,证明了所开发软件的正确性.     

五参胶囊镇静催眠作用及其机制的实验研究

目的观察五参胶囊(Wu Shen Capsules,WSh C)对小鼠镇静催眠作用的影响,并探讨其作用机制.方法将ICR小鼠随机分为对照组、五参胶囊高剂量组、中剂量组和低剂量组.五参胶囊高剂量组用药量为200 mg/(kg·d~(-1)),中剂量组用药量为100 mg/(kg·d~(-1)),低剂量组用药量为50 mg/(kg·d~(-1)),给药时间为15 d,于给药结束后进行小鼠自主活动实验和协同戊巴比妥钠阈上剂量睡眠时间实验,测定5 min内各组小鼠的活动次数和站立次数,记录各组小鼠的睡眠潜伏期和睡眠持续时间.采用酶联免疫吸附法检测小鼠下丘脑5-羟色胺(5-Hydroxytryptamine,5-HT)、5-羟吲哚乙酸(5-Hydroxyindole acetic acid,5-HIAA)、γ-氨基丁酸(γ-aminobutyric acid,GABA)、谷氨酸(glutamine,Glu)含量,并计算5-HIAA/5-HT比值及Glu/GABA比值.结果与对照组比较,WSh C各给药组小鼠活动次数减少,睡眠潜伏期缩短,睡眠持续时间延长(P0.01),WSh C能升高小鼠下丘脑5-HIAA含量和5-HIAA/5-HT比值,降低Glu含量和Glu/GABA比值.结论 WSh C具有明显镇静催眠作用,其机制可能与调节中枢兴奋性和抑制性神经递质有关.     

基于GM(1,1)模型的高速公路边坡稳定性研究

目的由于气象、地形及施工条件等的影响,高速公路边坡可能会发生滑塌,造成巨大的危害。针对边坡稳定性问题,分析边坡稳定性的影响因素。方法以现场边坡监控数据为依据,运用灰色预测GM(1,1)模型进行边坡稳定性预测。结果研究结果表明模型预测值与实测值误差较小,采用该预测模型可为技术人员提供数据支持,并根据所预测的结果来采取必要的安全措施以保证边坡的稳定性。结论灰色理论的运用和必要的监控对于确保边坡安全具有重要的指导意义。