Environmental application of elemental speciation analysis based on liquid or gas chromatography hyphenated to inductively coupled plasma mass spectrometry—A review

In recent years the number of environmental applications of elemental speciation analysis using inductively coupled plasma mass spectrometry (ICP-MS) as detector has increased significantly. The analytical characteristics, such as extremely low detection limits (LOD) for almost all elements, the wide linear range, the possibility for multi-elemental analysis and the possibility to apply isotope dilution mass spectrometry (IDMS) make ICP-MS an attractive tool for elemental speciation analysis. Two methodological approaches, i.e. the combination of ICP-MS with high performance liquid chromatography (HPLC) and gas chromatography (GC), dominate the field. Besides the investigation of metals and metalloids and their species (e.g. Sn, Hg, As), representing “classic” elements in environmental science, more recently other elements (e.g. P, S, Br, I) amenable to ICP-MS determination were addressed. In addition, the introduction of isotope dilution analysis and the development of isotopically labeled species-specific standards have contributed to the success of ICP-MS in the field. The aim of this review is to summarize these developments and to highlight recent trends in the environmental application of ICP-MS coupled to GC and HPLC.     

On the Dirac equation with PT-symmetric potentials in the presence of position-dependent mass

The relativistic problem of fermions subject to a PT-symmetric potential in the presence of position-dependent mass is reinvestigated. The influence of the PT-symmetric potential in the continuity equation and in the orthonormalization condition are analyzed. In addition, a misconception diffused in the literature on the interaction of neutral fermions is clarified.     

铂电阻非平衡电桥温度计的设计

利用Matlab和Origin软件,从理论上分析了电压型非平衡电桥铂金属温度计设计中,各种参数对温度线性度的影响。设计了0~100℃范围的温度计,获得电桥的输出电压和测量温度具有很好的线性关系。     

泛系哲学与泛系数学和应用：事理，物理，技理，医理与战理（Ⅰ）

这里从泛系观引入一种的哲学与数学研究，包括在乏系框架下 发展哲学七论与数学和一些第二第三哲学以及对事理、物理、技理、医理与战理的某些应用。     

EBA-LRU-SEQ Data Cache Policy in DSP to Optimize the Power Consumption

The power consumption by the data cache is important in DSP designs.This study presents an enhanced branch access LRU-SEQ(EBA-LRU-SEQ) policy for data caches in DSP designs to reduce the power consumption.The design is based on the LRU policy with embedded prefetch table to provide branch access.Tests show that the EBA-LRU-SEQ policy reduces the data cache power consumption to 54% of a system with no power control.     

Gap solitons of spin-orbit-coupled Bose-Einstein condensates in $\mathcal{PT}$ periodic potential

We numerically investigate the gap solitons in Bose-Einstein condensates (BECs) with spin-orbit coupling (SOC) in the parity-time ($\mathcal{PT}$)-symmetric periodic potential. We find that the depths and periods of the imaginary lattice have an important influence on the shape and stability of these single-peak gap solitons and double-peak gap solitons in the first band gap. The dynamics of these gap solitons are checked by the split-time-step Crank-Nicolson method. It is proved that the depths of the imaginary part of the $\mathcal{PT}$-symmetric periodic potential gradually increase, and the gap solitons become unstable. But the different periods of imaginary part hardly affect the stability of the gap solitons in the corresponding parameter interval.     

Electrorheology and characterization of acrylic rubber and lead titanate composite materials

Oxide one‐pot synthesis was used to synthesize a polymer precursor to lead titanate, PbTiO₃. Perovskite lead titanate, PbTiO₃, was synthesized via the sol–gel process. The dielectric constant, electrical conductivity and loss tangent of our acrylic rubber (AR71)–lead titanate (PT) composite material (AR/PT_8) were 14.15, 2.62 × 10^?7/Ω m, and 0.093, respectively, measured at 27 °C and 1000 Hz. SEM micrographs of composites between the AR71 elastomer and PbTiO₃ showed that the particles were reinforced within the matrix. The electrorheological properties of the AR71/PT composites were investigated as functions of electric field strength from 0 to 2 kV/mm and PbTiO₃ particle volume fraction. The storage modulus increased linearly with particle volume fraction, with or without an electric field. Without an electric field, the particles merely acted as a filler to absorb or store additional stress. With the electric field on, particle‐induced dipole moments were generated, leading to interparticle interactions, and thus a substantial increase in storage modulus. With PbTiO₃ particle volume fractions as small as 10^?4 embedded in the elastomer matrix, the modulus increased by nearly a factor of 2 as the electric field strength varied from 0 to 2 kV/mm. Copyright © 2008 John Wiley & Sons, Ltd.     

学校体育在实施素质教育过程中应处理好的几个问题

以素质教育为指导思想的学校体育的改革，实质上是对传统体育教学的哲学扬弃，因此，必须站在辩证分析的哲学高度上，来认识过去的传统学校体育，在学校体育改革中处理好批判、继承和发展的问题。     

Geometry of time-dependent $\mathcal{PT}$-symmetric quantum mechanics

A new type of quantum theory known as time-dependent $\mathcal{PT}$-symmetric quantum mechanics has received much attention recently. It has a conceptually intriguing feature of equipping the Hilbert space of a $\mathcal{PT}$-symmetric system with a time-varying inner product. In this work, we explore the geometry of time-dependent $\mathcal{PT}$-symmetric quantum mechanics. We find that a geometric phase can emerge naturally from the cyclic evolution of a $\mathcal{PT}$-symmetric system, and further formulate a series of related differential-geometry concepts, including connection, curvature, parallel transport, metric tensor, and quantum geometric tensor. These findings constitute a useful, perhaps indispensible, tool to investigate geometric properties of $\mathcal{PT}$-symmetric systems with time-varying system's parameters. To exemplify the application of our findings, we show that the unconventional geometric phase [Phys. Rev. Lett. 91 187902 (2003)], which is the sum of a geometric phase and a dynamical phase proportional to the geometric phase, can be expressed as a single geometric phase unveiled in this work.