ICP法测定朱鹮羽毛中7种元素含量

用电感耦合等离子体(ICP)发射光谱法直接测定世界珍稀濒危鸟类——朱鹮羽毛中Cu,Zn,Mn,Ni,Cr,Fe,Mo七种元素的含量。结果表明,此方法简便,具有良好的精密度和准确性。     

Bubble tree convergence for the harmonic sequence of harmonic surfaces in ℂℙ n

We show that any harmonic sequence determined by a harmonic map from a compact Riemannian surface M to CP^n has a terminating holomorphic （or anti-holomorphic） map from M to CP^n, or a ＂bubble tree limit＂ consisting of a harmonic map f： M → CP^n and a tree of bubbles hλ^μ： S^2 --→ CP^n.     

一种具有二次谐波发生和适中双折射的紫外透过稀土金属甲酸盐

本研究工作报道了一例采用溶液挥发法合成的稀土金属甲酸盐，分子式为(C(NH₂)₃)[Er(HCOO)₄]。该化合物结晶于非中心对称空间群。光学性质研究表明：该化合物具有较大光学带隙(4.76 eV)、适中的双折射率(0.066@546 nm)；在1 064 nm处，其粉末倍频效应为KH₂PO₄(KDP)的0.2倍，并且可实现相位匹配。第一性原理计算和单晶结构分析揭示了线性和非线性光学效应来源于C (NH₂)₃⁺、[ErO₈]和HCOO^-单元的协同作用。     

Investigation of linear and nonlinear frequency modulated excitation effects on tissue harmonic imaging

The generation of tissue harmonics is due to nonlinear nature of ultrasound wave propagation in biological tissues.The tissue harmonics for imaging i.e.tissue harmonic imaging (THI)uses higher frequency components for imaging in which the resolution improves significantly but signal-to-noise ratio(SNR)and penetration depth remains low as compared to both fundamental and second harmonic imaging.The coded excitations have potential to improve the SNR which ultimately leads to improved penetration depth.In the present work,the linear frequency modulated(chirp/LFM)and nonlinear frequency modulated(NLFM)signals have been used to investigate the nonlinear ultrasound wave propagation and harmonic generation in biological tissues.The SNR has been found to be substantially improved for coded tissue harmonic imaging(CTHI)as well as for coded superharmonic imaging(CSHI).     

基于Linux的多频高频地波雷达LXI总线模件设计

在以ARM芯片为核心的硬件平台上,设计了一种通用的LXI总线模件,可作为多频高频地波雷达的系统总线.它以AT91RM9200,DM9161和IDT7028芯片为硬件基础,Linux操作系统为软件平台,利用Linux内核的同步机制来保证系统运行的稳定性,采取全双工的双向中断方式实现大量数据包的传送,满足了多频高频地波雷达总线模件的接口要求,并提供了一套有效的系统测试方案.测试结果表明,该LXI总线接口模件稳定性好、可靠性高,网络数据传输平均速度为45 Mb/s,达到了多频高频地波雷达总线模件的设计要求.     

HORIZONTAL LAPLACE OPERATOR IN REAL FINSLER VECTOR BUNDLES

A vector bundle F over the tangent bundle TM of a manifold M is said to be a Finsler vector bundle if it is isomorphic to the pull-back π^＊E of a vector bundle E over M（[1]）. In this article the authors study the h-Laplace operator in Finsler vector bundles. An h-Laplace operator is defined, first for functions and then for horizontal Finsler forms on E. Using the h-Laplace operator, the authors define the h-harmonic function and ho harmonic horizontal Finsler vector fields, and furthermore prove some integral formulas for the h-Laplace operator, horizontal Finsler vector fields, and scalar fields on E.     

高频炉燃烧-红外吸收光谱法测定水泥中三氧化硫含量

水泥是国民经济建设的重要基础原材料。水泥中的三氧化硫含量是评定水泥品质的重要指标,也是产品质量检验的必检项目,三氧化硫含量对水泥产品的性能和质量的影响较大。水泥中的三氧化硫主要来源于调节凝结时间的石膏、高温煅烧熟料加入的矿化剂或原燃材料。适量的三氧化硫能调节水泥的凝结时间、改善水泥性能,但三氧化硫含量过高,会在水泥硬化后继续与水和铝酸三钙反应形成     

Cumulative solutions of nonlinear longitudinal vibration in isotropic solid bars

Based on the strain invariant relationship and taking the high-order elastic energy into account, a nonlinear wave equation is derived, in which the excitation, linear damping, and the other nonlinear terms are regarded as the first-order correction to the linear wave equation. To solve the equation, the biggest challenge is that the secular terms exist not only in the fundamental wave equation but also in the harmonic wave equation （unlike the Duffing oscillator, where they exist only in the fundamental wave equation）. In order to overcome this difficulty and to obtain a steady periodic solution by the perturbation technique, the following procedures are taken： （i） for the fundamental wave equation, the secular term is eliminated and therefore a frequency response equation is obtained; （ii） for the harmonics, the cumulative solutions are sought by the Lagrange variation parameter method. It is shown by the results obtained that the second- and higher-order harmonic waves exist in a vibrating bar, of which the amplitude increases linearly with the distance from the source when its length is much more than the wavelength; the shift of the resonant peak and the amplitudes of the harmonic waves depend closely on nonlinear coefficients; there are similarities to a certain extent among the amplitudes of the odd- （or even-） order harmonics, based on which the nonlinear coefficients can be determined by varying the strain and measuring the amplitudes of the harmonic waves in different locations.     

Probing dynamic interference in high-order harmonic generation from long-range molecular ion:Bohmian trajectory investigation

Using Bohmlan trajectory （151） method, we investigate the dynamic interference in nlgn-orcter narmonlc generauon from diatomic molecular ions. It is demonstrated that the main characteristics of the molecular harmonic spectrum can be well reproduced by only two BTs which are located at the two ions. This haiapens because these two localized trajectories can receive and store the whole collision information coming from all of the other re-collision trajectories. Therefore, the amplitudes and frequencies of these two trajectories represent the intensity and frequency distribution of the harmonic generation. Moreover, the interference between these two trajectories shows a dip in the harmonic spectrum, which reveals the molecular structure information.