X-ray spectra induced by slow highly charged Ar q + ions in collision with Nb surface

The X-ray spectra of Nb surface induced by Ar ^q+ (q = 16,17) ions with the energy range from 10 to 20 keV/q were studied by the optical spectrum technology. The experimental results indicate that the multi-electron excitation occurred as a highly charged Ar¹⁶⁺ ion was neutralized below the metal surface. The K shell electron of Ar¹⁶⁺ was excited and then de-excited cascadly to emit K X-ray. The intensity of the X-ray emitted from K shell of the hollow Ar atom decreased with the increase of projectile kinetic energy. The intensity of the X-ray emitted from L shell of the target atom Nb increased with the increase of projectile kinetic energy. The X-ray yield of Ar¹⁷⁺ is three magnitude orders larger than that of Ar¹⁶⁺. Supported by the National Natural Science Foundation of China (Grant Nos.10774149 and 10405025)     

特征2的有限域中一些特殊元素的存在性(II)

设q=2s.s,n为正整数,Fqn为qn元素的有限域.在本文中,我们考虑Fqn中一些特殊元素的存在性.主要结果是:当下面的条件之一成立时,在Fqn中存在ξ使得ξ和ξ+ξ-1都是本原元并且ξ+ξ-1还是一个正规元:1.当n|(q-1)时,n37,s>6,或者2.当n|■(q-1)时,n≥34,s>6.进一步,如果n是奇数,则当下列条件之一成立时,存在ξ∈Fqn使得ξ和ξ+ξ-1都是Fqn的本原正规元:1.当n|(q-1)时,n≥257,s>9,或者2.当n■(q-1)时,n≥43,s≥9.     

The ranks of Maiorana-McFarland bent functions

In this paper, the ranks of a special family of Maiorana-McFarland bent functions are discussed. The upper and lower bounds of the ranks are given and those bent functions whose ranks achieve these bounds are determined. As a consequence, the inequivalence of some bent functions are derived. Furthermore, the ranks of the functions of this family are calculated when t 6.     

Iodine Catalyzed Three-component Strecker-type Synthesis of α-Aminonitriles from Aldehydes, Amines and Tributyltin Cyanide

A simple and efficient one-pot method has been developed for the synthesis of a-aminonitriles from aldehydes, amines and tributyltin cyanide in the presence of a catalytic amount of iodine with high yields. The reactions proceeded smoothly at room temperature via very simple procedure.     

Preparation of grain size controlled boron-doped diamond thin films and their applications in selective detection of glucose in basic solutions

Boron-doped diamond (BDD) thin films with different crystal grain sizes were prepared by controlling the reacting gas pressure using hot filament chemical vapor deposition (HFCVD). The morphologies and structures of the prepared diamond thin films were characterized by scanning electron microscopy (SEM) and Raman spectroscopy. The electrochemical responses of K₄Fe(CN)₆ on different BDD electrodes were investigated. The results suggested that electron transfer was faster at the boron-doped nanocrystalline diamond (BDND) thin film electrodes in comparison with that at other BDD thin film electrodes. The prepared BDD thin film electrodes without any modification were used to directly detect glucose in the basic solution. The results showed that the as-prepared BDD thin film electrodes exhibited good selectivity for detecting glucose in the presence of ascorbic acid (AA) and uric acid (UA). The higher sensitivity was observed on the BDND thin film grown on the boron-doped microcrystalline diamond (BDMD) thin film surface, and the linear response range, sensitivity and the low detection limit were 0.25–10 mM, 189.1 μA mmo^?1 cm^?2 and 25 μM (S/N=3) for glucose in the presence of AA and UA, respectively.     

Formulation of elastic multi-structures

Based on the creative and groundbreaking work done by Feng and Shi, some further work has been carried out comprehensively by the first author on the formulation of elastic multi-structures. The main contribution of this paper can be summarized as follows: The work of Feng and Shi has been extended to an elastic multi-structures with nonlinear structural element: shell in both linear and nonlinear case. Three general combinations of multi-structures have been formulated, that is, Case 1: linear elements of 3-D body, 1-D bar/beam, 2-D plates and 2-D shell; Case 2: nonlinear elements of 3-D body, 1-D bar/beam, 2-D plates and 2-D shell; and Case 3: the linear-nonlinear mix problem of 3-D body (nonlinear), 1-D bar/beam (linear), 2-D plates (linear) and 2-D shell (linear). From the investigation, it has proved that the higher dimensional element will have a strong influence on the lower one with the inner linkage boundaries, and also proved that solution uniqueness of elastic multi-structures is different from a single 3-D body.     

Realization of population inversion between 7S1/2 and 6P3/2 levels of cesium for four-level active optical clock

We demonstrate experimentally the population inversion between 7S1/2 and 6P3/2 levels of cesium in thermal cesium cell with a 455.5 nm pumping laser.We calculate the relative population probabilities at each level theoretically with the density matrix method.In a steady state,5.8% atoms are at 7S1/2 level and 2.9% at 6P3/2 level,which builds up the population inversion between the two levels.We obtain the fluorescence spectra produced in thermal cesium cell in our experiment.The measured relative intensity of each available fluorescence spectral line in the experiment agrees very well with the theoretical result.The demonstrated population inversion between 7S1/2 and 6P3/2 levels can be used to construct an active optical clock of four-level system with a wavelength of 1469.9 nm.     

Diagonalizat ion of Multi-Oscillat or Models and Level-Spacing Distributions

Three-body oscillator in three-dimensional space is exactly solved and its levelspacing distribution P(s) is studied. Multi-coupled oscillator can also be diagonalized with its level-spacing distribution discussed. It is found that P(s) is very unstable and it is connected tightly with the parameters of the system.     

On higher-dimensional contrast structure of singularly perturbed Dirichlet problem

In this paper,we address the existence and asymptotic analysis of higher-dimensional contrast structure of singularly perturbed Dirichlet problem.Based on the existence,an asymptotical analysis of a steplike contrast structure (i.e.,an internal transition layer solution) is studied by the boundary function method via a proposed smooth connection.In the framework of this paper,we propose a first integral condition,under which the existence of a heteroclinic orbit connecting two equilibrium points is ensured in a higher-dimensional fast phase space.Then,the step-like contrast structure is constructed,and the internal transition time is determined.Meanwhile,the uniformly valid asymptotical expansion of such an available step-like contrast structure is obtained.Finally,an example is presented to illustrate the result.     

对流边界层湍流特性的数值研究

采用大涡模拟方法研究了存在逆温层的情况下大气对流边界层的湍流特性。实际大气边界层中出现逆温层是较常见的，逆温层会导致大气边界层湍流结构的变化，从而影响大气的湍流扩散和输运特性。本文比较了不同逆温梯度的工况，着重分析了逆温层对边界层中热量逆梯度输运（counter gradient heat transportation，CGHT）的影响。计算结果表明：逆温梯度越大，对流边界层的发展越受到抑制；逆温层高度降低会影响整个对流边界层的温度抬升；逆温梯度越大，垂直速度方差越小；在逆温梯度较大的情况下，其逆梯度输运区域要略微低一些，初步分析认为是由于逆温层对热对流的抑制造成的；对于逆温层高度不同的情况，高度越低的逆温层对逆梯度输运的抑制作用更明显。