关于区间上的单峰扩张自映射

设ｆ是区间Ｉ＝［０，１］上的扩张的单峰函数，λ是ｆ的扩张常数。又设Ｋ≥３是奇数，ｎ≥３是整数，λｋ是方程ｘ＾ｋ－２ｘ＾ｋ－２－１＝０的最大实根，μｎ是方程ｘ＾ｎ－２ｘ＾ｎ－１＋１＝０的最大实根，本文用较简单的方法证明了，当λ≥λＫ时，ｆ中含有Ｋ－周期轨道，当λ≥μｎ时，ｆ中含有相对于自身的ＲＬ＾ｎ－２Ｃ型单峰周期轨道。此外，本文还讨论了一类方程ｘ＾ｎη（ｘ）＝ζ（ｘ）的根的极限度最性质。     

Sonochemical Method for the Preparation of Hollow SnO2 Microspheres

A simple sonochemical route has been successfully developed to synthesize SnO_2 hollow microspheres.Theobtained sample is characterized by XRD,TEM,XPS and UV-visible spectrophotometer.The TEM image of thesample at high magnification shows that the shell of the hollow sphere is composed of 3-5 nm SnO_2 nanoparticles.A possible formation mechanism of the hollow spheres is briefly discussed.     

银纳米三角片二聚体的近场辐射分析

本文使用FDTD法对典型尺寸的银纳米三角片二聚体在不同偏振光源及不同聚集结构下的近场辐射特性进行了模拟计算,结果发现:不同光源偏振方向和粒子聚集结构能够显著影响银纳米三角片的辐射特性和场增强效应的空间分布。偏振方向垂直于边长时,三种聚集结构的场增强系数最大值均大于偏振方向平行于边长时的情况,并且在点对点结构下,两粒子的中间位置处具有最强的场增强效应。     

电热原子吸收光谱法测定钢铁样品中的痕量钙

采用电热原子吸收光谱法测定了钢铁样品中的痕量钙,加标回收率为95.0％-110.0％,相对标准偏差在4.6％-6.4％之间,本法适用于那些不具备昂贵价格大型仪器的实验室,更适用于生产流程控制检测.     

盐酸青藤碱肠溶片的健康人体生物等效性

建立了测定人血浆中盐酸青藤碱的高效液相色谱法(HPLC),研究盐酸青藤碱肠溶片在男性健康志愿者体内的药动学行为,评价其人体相对生物利用度和生物等效性.18例健康男性志愿者随机分组自身交叉对照试验设计,单剂量口服盐酸青藤碱肠溶片受试制剂和参比制剂80mg,HPLC测定服药后36h内不同时间血浆中盐酸青藤碱的浓度,BAPP药动学程序计算相对生物利用度并评价两种制剂生物等效性.受试制剂和参比制剂的主要药动学参数:tmax分别为(2.36±0.64)h和(2.56±0.62)h;Cmax分别为(838.05±145.78)ng·mL-1和(819.46±105.77)ng·mL-1;t1/2分别为(11.29±1.95)h和(10.10±2.75)h,药时曲线下面积AUC(0→36h)分别为(5850.39±1805.83)ng·h·mL-1和(6134.85±1862.25)ng·h·mL-1.受试制剂与参比制剂的相对生物利用度为(101.1±36.1)％.建立的分析方法准确灵敏,测得的数据可靠,统计学分析表明两种制剂生物等效.     

An Effective Three-Dimensional Micromagnetic Method and Its Application to Magnetic Tunnel Junctions

An effective three-dimensional micromagnetic method for predicting equilibrium configuration of magnetization states is presented with conjugate-gradient technique to minimize the total energy, which has a much faster convergence rate than that of the quasi-Newton method. As an application, magnetic tunnel junctions with pinholes in the ultrathin barrier are simulated. The calculated coupling field Hf increases with the pinhole density increase, corresponding to the decrease of barrier thickness. The free layer domain configuration of tunnel junction during the switching process is also demonstrated.     

Diquark Structure of Pentaquark in the Quark Delocalization Colour Screening Model

In the framework of quark-delocalization, colour-screening model, the diquark structure of pentaquark θ^＋ is studied in detail under the adiabatic approximation. The calculation is carried out by using the fractional parentage expansion technique, which greatly simplify the calculation of the matrix elements of Hamiltonian. The results show that the ground state of the pentaquark has negative parity rather than positive parity, which was proposed by daffe-Wilczek. However the mass obtained is about 1651 MeV which is still higher than the observed mass 1540 MeV.     

Simultaneous Elastic Recoil Detection Analysis of H and Other Elements in Foils

Hydrogen and other elements in SixNyHz foils have been simultaneously measured by using a single E（gas）- E（PSD） telescope and heavy ^127I ion beam in elastic recoil detection analysis （ERDA）. Hydrogen is measured in the non-coincidence spectrum of E（PSD）, and other elements from the △E - E coincidence spectrum. The composition and depth profiling of the foils are obtained from the simulated spectra.     

湿蒸汽两相流动问题的耦合求解

控制湿蒸汽两相流动(汽相和液相)的方程个数多,其数值模拟通常采用将两相分开、两相间用参数传递的方法来处理。本文首次尝试将湿蒸汽两相流动汽相和液相的8个控制方程统一求解,推导了这一方程组的特征值及对应的特征向量,结合控制体积方法,采用TVD格式和时间推进法数值求解这一耦合方程组,研发了相应计算软件。对二维喷管中的自发凝结和非均质凝结算例进行的数值模拟和分析,表明了本文方法和计算软件的有效性和可靠性。     

氢化物发生-原子荧光光谱法同时测定磷酸盐中砷和锑

采用盐酸溶解三聚磷酸钠、磷酸氢钙试样,氢化物发生-原子荧光光谱法同时测定砷和锑,对仪器条件、盐酸、预还原剂、还原剂用量、共存离子干扰进行了试验。方法的检出限砷为6.3ng·g-1,锑为6.8ng·g-1,砷的测定精密度为1.14%—5.42%,回收率为99.4%—103.5%,锑的测定精密度为1.25%—1.77%,回收率为98.0%—101.9%。