Convergence of vortex methods for weak solutions to the 2-D euler equations with vortex sheet data

We prove the convergence of vortex blob methods to classical weak solutions for the two-dimensional incompressible Euler equations with initial data satisfying the conditions that the vorticity is a finite Radon measure of distinguished sign and the kinetic energy is locally bounded. This includes the important example of vortex sheets. The result is valid as long as the computational grid size h does not exceed the smoothing blob size ε, i.e., h/ε ≦ C.. ©1995 John Wiley & Sons, Inc.     

Measurements of Absorption and Anisotropy Coefficients of the Fat Emulsion Intralipid-10%

We report measurements of absorption and anisotropy coefficients of the fat emulsion Intralipid-10%. An addingabsorber method is used for measurement of absorption and anisotropy coefficients of the Intralipid-10%. Using the diffusion theory which has been extended to include anisotropy scat geometry, we found that the standard deviations of multiple measurements for√μα/D are less than 0.6% and the residuals between the measured data and the fits have rms values of 0.1%, where μα is the absorbing coefficient of the solution in our experiment and D is the diffusion coefficient of the medium. The values of the standard deviations and the residuals demonstrate the high precision of the measurements.     

Influence of laser intensity in second-harmonic detection with tunable diode laser multi-pass absorption spectroscopy

Tunable diode laser absorption spectroscopy （TDLAS） has been widely employed in atmospheric trace gases detection. The ratio of the second-harmonic signal to the intensity of laser beam incident to the multi-pass cell is proved to be proportional to the product of the path length and the gas concentration under any condition. A new calibration method based on this relation in TDLAS system for the measurement of trace gas concentration is proposed for the first time. The detection limit and the sensitivity of the system are below 110 and 31ppbv （parts-per-billion in volume）, respectively.     

MFSK浅海远程通信多径抑制的频率分组编码方法

多频移键控调制技术（MFSK）对信道衰落有良好的适应性，是远程水声通信的重要技术。但是，用于浅海远程水声通信时，由于多径传播的影响，导致严重的码间干扰（ISI），使得远程微弱信号的频率估计产生较大偏差，误码率显著增加。本文针对远程水下信道和MFSK调制的特点，提出了一种新的频率分组编码（FGC）方法。该方法改变了传统MFSK的数据帧格式，相邻符号采用不同组的频率进行编码映射，有效抑制了多径干扰。在深入研究新方法统计特性的基础上进行了湖试验证，结果表明，采用FGC新方法的通信系统，多径抑制有效，性能稳健，更适合于80-100km水声远程通信。     

Synthesis, crystal structure and thermal stability of a novel 3D microporous coordination polymer: Na2[Co(1,4-napdc)2(DMF)2]

A new 3D inorganic–organic hybrid framework microporous material Na₂Co(1,4-napdc)₂(DMF)₂(1,4-napdc =  napthalene-1,4-dicarboxylate), which is constructed by coordination of cobalt ion and sodium ions with napthalene-1,4-dicarboxylate and DMF, is synthesized under solvothermal conditions. Two bidentate-bridging and two chelate-bridged carboxylate link a cobalt (II) and two sodiums (I) to the dimer structure. The square grids constructed with the caged-laddered-shaped secondary building units (SBUs) built by Co–O–Na–O and Co–O–C–O bond and 1,4-napdc links stack over each other to generate infinite 3D networks, which have a microporous channel (11.05 × 11.05 Å²) along the crystallographic c-axis. The thermal stability of the compound was investigated by differential scanning calorimetric and thermogravimetric analysis. The complexes could be anticipated as potential heat-resistant energetic material.     

高浓度镱铒共掺磷酸盐光纤放大器增益特性

在忽略高能级的自发辐射和光纤损耗的情况下，利用速率方程和传输方程理论研究了高浓度Er³⁺/Yb³⁺共掺磷酸盐玻璃光纤放大器的增益特性，讨论了Er³⁺浓度、Yb³⁺浓度、抽运光功率、信号光功率、光纤长度对放大器增益的影响，并与单掺铒光纤放大器进行了比较.由于Yb³⁺的敏化作用降低了铒离子的团簇效应，减少了离子间相互作用，共掺光纤的增益和效率明显高于单掺光纤.数值计算表明，3.2cm长Er³⁺/Yb³⁺共掺光纤在980nm的20dBm(100mW)抽运功率下，1532nm处的增益可达10dB. 关键词： 镱铒共掺光纤放大器 速率方程 传输方程 高浓度     

丙酮+环己烷+甲醇组成的最低共沸混合物热力学性质的研究

Mesoporous molecular sieves Al-MSU-S has been prepared from the precursor of zeolite Y using ionic liquids 1-hexadecane-3-methylimidazolium bromide （CMIMB） as a template in basic medium, which exhibited larger pore diameter, pore volume and surface area than that synthesized using cetyl trimethyl ammonium bromide （CTAB） template.     

Integration Technique of Multi-source Information Dominated by Aerial Radiometric Measure-ment and Its Application

This paper aims at exploring a digital image integration technique for multi-geoscience in formation dominated by airborne gamma-ray data, especially deeply discussing the method to secondly develop those aerial data by combining digital image processing system with the colored mapping system. Utilizing this technique , we have analyzed the geologic environment of uranium mineralization of Lianshanguan area > Liaoning Province, provided some important background information for further seeking of minerals. Meanwhile , experimental studies have been made to predict uranium mineralization , and evident results aquired. Practise shows that this new technique offers prospecting significance for mineral seeking and great practical value in survey of uranium resources.     

Approximately analytical solutions of nonlinear te-mode surface waves on a metallic substrate

Using the Rayleigh-Schrödinger Technique (RST) the approximately analytical solutions of weaky nonlinear TE surface waves are presented. The results show that the velocity cut-off requencies and the dispersion relations of the waves have to do with the magnitude of waves.     

Properties of high-Tc superconducting circular waveguides with Meissner boundary

The propagation properties of the TE-modes in a high-temperature superconducting circular waveguide using the Mei\ner boundary conditions on the wall are presented for the first time. The results show that now the normalized cutoff parameterk _c R, (whereR is the radius of the superconducting circular waveguide andk _c the cutoff wavenumber,) is dependent on the radius unlike conventional metallic circular waveguide whose normalized cutoff parameterk _c R is a constant for a given mode and the filled dielectrics. Instead of TE₁₁-mode now TE₀₁ mode becomes the dominant mode and the normal component of magnetic field for the dominant mode is not equal to zero on the wall. Other unique results of high-T _c superconducting circular waveguides are illustrated, too.supported by Deutscher Akademischer Austauschdienst (DAAD)