Loss of Trace Elements From Natural Water During Storage 2. Behavior of 203HgCl2, CH3 203HgCl and 65ZnCl2 Added to Marine Water

Dilute solutions (10–50 ppb) of mercury and zinc are prepared using artificial marine water and natural marine water, labelled with ²⁰³Hg and ⁶⁵Zn.

²⁰³Hg in inorganic form is lost considerably from both solutions caused by vaporization to the atomosphere and presumably by adsorption to the surface of containers. In natural marine water some biological activities participate for the behavior of both metals but it seems to be in smaller extent than that in pond water. ⁶⁵Zn remained constant with no loss under these experimental conditions.

When CH₃ ²⁰³HgC1 is added to the solution instead of ²⁰³HgC1₂, ²⁰³Hg is scarcely lost but a smaller amount is observed to be lost by vaporization from well-test tubes. In natural marine water, however, CH₃ ²⁰³HgC1 is also lost in the similar manner as ²⁰³HgC1₂.     

Breakdown Criterion for a Conservation Law with Saturating Dissipation

ABSTRACT

A sufficient condition is given for smooth solutions of a scalar conservation law with a saturating viscous term to develop shocks.     

Cut-off frequency of magnetostrictive materials based on permeability spectra

The loss behavior and cut-off frequency of TbDyFe alloy and TbDyFe/epoxy composite have been investigated by measuring their permeability spectra. The loss factor of TbDyFe alloy increases exponentially as the frequency goes up, while it is almost unchanged for the TbDyFe/epoxy composite. The loss factor value for the TbDyFe composite is only 4.3% of that for the monolithic TbDyFe alloy at high frequency of 10 kHz under the peak magnetic induction of 10 mT. The cut-off frequency of TbDyFe/epoxy composite is 6800 kHz, 3 orders of magnitude larger than that of TbDyFe alloy. The cut-off frequency is found to be the ferromagnetic resonance frequency and can be calculated from Snoek's law.     

Influence of composition of carbonyl iron particles on dynamic mechanical properties of magnetorheological elastomers

Magnetorheological elastomers (MRE) are known as smart materials. However, the magnetorheological (MR) effect of MRE is not high enough at present, which limits its engineering applications. Prior studies have shown that magneto-induced shear storage modulus and MR effect were mainly determined by the performance of the ferromagnetic particles. In this paper, MRE samples were prepared by carbonyl iron particles (CIP) of different compositions based on silicon rubber under external magnetic field. Their microstructures were observed using an optical digital microscope and a scanning electron microscope. The dynamic mechanical properties of MRE samples were measured using a modified dynamic mechanical analyzer under varying magnetic field strength and frequency. The results show that the carbon content of CIP have a greater impact on the dynamic mechanical properties of MRE. The magneto-induced shear storage modulus and MR effect can be increased by selecting CIP of low carbon content. In addition, the damping property is also significantly influenced by the carbon content of the CIP. This study is expected to provide guidance for fabrication of high performance MRE.     

基于碲酸盐的新型单芯光子晶体光纤偏振分束器

提出了一种基于ZnTe碲酸盐玻璃的单芯光子晶体光纤偏振分束器.在外侧包层纤芯对称位置引入缺陷孔,使缺陷模和纤芯基模发生耦合以实现光束分离.采用全矢量有限元法对所提出的单芯光子晶体光纤偏振分束器的特性进行研究,结果表明:该分束器可以实现1.3μm和1.55μm波长光的分离,并使光束沿X和Y偏振方向同时传播;当光纤长度为15mm时,1.3μm和1.55μm处的串扰值分别低至-45.1dB和-40.2dB,小于-20dB的带宽分别为44.2nm和67.1nm;在传输波长1.3μm和1.55μm处的损耗值为0.063dB和0.048dB;偏振分束器在具有低串扰值的同时,具有较低的限制损耗.     

The fundamental surface science of wurtzite gallium nitride

A review is presented that covers the experimental and theoretical literature relating to the preparation, electronic structure and chemical and physical properties of the surfaces of the wurtzite form of GaN. The discussion includes the adsorption of various chemical elements and of inorganic, organometallic and organic species. The focus is on work that contributes to a microscopic, atomistic understanding of GaN surfaces and interfaces, and the review concludes with an assessment of possible future directions.     

基于微机的失磁保护装置

基于微型计算机的失磁保护装置因其主体是计算机,所以具有很强的计算功能及记忆功能,这些特点使得保护装置可以较高精度地实现复杂的保护特性.本文所述装置的硬件由单板机及扩展的一些外部装置组成,外部装置包括数据采集系统及打印机、开关控制设备等.软件由调试和运行两大部分组成,实现了单个单板机既能作开发工具,也能作运行主机的目的.     

Dielectric and magnetic properties of xNiFe2O4+(1−x)Ba0.9Sr0.1TiO3 composites

Magnetoelectric composites, namely, xNiFe₂O₄+(1−x)Ba_0.9Sr_0.1TiO₃ were prepared by standard double sintering ceramic method. The X-ray diffraction analysis was carried out to check the phases formed during sintering and to calculate the lattice parameters. Scanning electron microscope (SEM) micrographs were taken to understand the microstructure of the samples. The dielectric constant (ε′) and loss tangent (tan δ) were measured as a function of frequency in the frequency range 100 Hz–1 MHz. Variation of dielectric constant and loss tangent with temperature and composition has been reported. The hysteresis measurements were done to determine saturation magnetization (M_S) and coersivity (H_c). The variation of saturation magnetization and magnetic moment is interpreted in terms of composition.     

The Effects of Polarization and Non-Linearity on the Performance of WDM System with Optical Cross-Connects

The performance of a wavelength division multiplexing (WDM) system with optical cross-connects (OXCs) and in the presence of polarization and nonlinear effects was analyzed. We determined the effect of PMD and PDL; nonlinearity such as XPM, SPM, and FWM; and CD on the system performance. We found that the system outage probability is highest at DGD threshold for the respective maximum eye closure (EC). We showed that the allowable DGD depends on the time slot for one bit T, which is the inverse of the network bit rate. Wider T is more immune to large PMD with the EC still maintained at the same level since DGD/T is unchanged. Our analysis also indicated that as DGD increases, BER increases. The BER also increases with increase in PDL and further increases with the presence of XPM, SPM, FWM, and CD.     

Analysis of integrated corner mirrors by using a wide-angle beam propagation method

An integrated corner mirror is analyzed by using a two-dimensional (2D) wide-angle beam propagation method (WA-BPM) combining with an effective index method (EIM). Both the reflection efficiency and the phase variation due to a total internal reflection (TIR) for the TE and TM modes are calculated. A non-perfect fabrication (such as a tilted or displaced mirror) introduces an additional reflection loss and some errors of the phase variation. The additional reflection loss due to a tilted mirror increases rapidly as the tilted angle increases and becomes more sensitive to the tilted angle when the confinement of the waveguide becomes weaker. It is shown that the displacement of a mirror influences the phase variation greatly and the difference of the phase variation between the TE and TM modes is not sensitive to the displacement of the mirror.