广州珠江水体微表层与次表层中重金属的分布特征

采用ICP-AES对广州珠江水体微表层与次表层中Cu、As、Zn、Cr、Pb和Cd的质量浓度进行为期一年的调查研究。结果表明：珠江广州段水体均不同程度地受到6种重金属的污染,重金属浓度的季节性变化比较明显,在春季和冬季时浓度较高,夏季时浓度较低;重金属浓度的空间变化也比较明显。除Zn外,微表层对其余5种重金属均具有较强的富集作用。     

一次消解测定蔬菜中多种重金属的简捷方法

针对一般实验室检测人员少,检测任务重的问题,研究了蔬菜通过一次湿化消解后,消解液可以测定多种重金属元素的方法,大大提高了效率,减轻了工作量.     

Nanoparticle and Nanoporous Carbon Adsorbents for Removal of Trace Organic Contaminants from Water

Removal of a wide range of trace organic contaminants from water to concentrations below USEPA Maximum Contaminant Levels (MCL) remains an important goal for the water industry. Design of advanced carbon based adsorption systems represents a unique approach to solving these problems. A number of successful examples are cited in this paper and are briefly summarized in the following section.

1. Removal of foulants such as humic acid using nanoparticle carbon blacks and chemically activated nanoporous fibers;
2. Removal of trace organic contaminants such as benzene, toluene, ethylbenzene and p-xylene (BTEX) to levels below USEPA MCL using nanoporous carbon fibers;
3. Removal of trace chemical warfare simulants such as diisopropylmethyl phosponate and chloroethylethylsulfide using enlarged nanoporous carbon fibers;
4. Removal of trace chlorinated solvents such as trichloroethylene (TCE) and chloroform using tailored nanoporous carbon fibers;
5. Removal of the trace herbicide, atrazine, to below USEPA MCL level using nanoporous chemically activated fibers.

In this paper the enormous improvement of the above systems over commercially available products in static and dynamic adsorption evaluation is described.     

用阶乘矩技术提高相对论重离子碰撞实验数据样本中QGP事件比例的方法

在相对论重离子碰撞中形成QGP时,与之相伴随的有一些非QGP背景事件．把末态（方位角、快度）二维相空间中阶乘矩剧烈上翘的消失与一些普遍认为的QGP信号（如K／π比的上升）联系起来讨论,提出了一种从实验数据中挑选候选的QGP事件的方法．用Mont－Carlo模拟表明,这种方法有效地提高了挑选出来的子样本中QGP事件的信噪比．     

Evolution of the Continuous-Atomistic Method for the Simulation of Processes of the Interaction between Heavy Ions and Metals

The evolution of the continuous-atomistic approach to the simulation of processes of the interaction between high-energy heavy ions and metals is presented in this paper. The continuous-atomistic model is described by two different classes of equations, namely, thermal-conductivity equations with a source in the thermal-spike model and equations of motion of material points irradiated with a beam in a model of molecular dynamics. A software package is developed for simulation within the framework of the continuous-atomistic model. The results of simulation of the processes of metal-target irradiation with high-energy heavy ions depending on the parameters of the source function and the electron–phonon interaction coefficient are obtained.     

Development of the Technique for Fabricating Submicron Moire Gratings on Metal Materials Using Focused Ion Beam Milling

A focused gallium ion （Ga＋） beam is used to fabricate micro/submicron spacing gratings on the surface of porous NiTi shape memory alloy （SMA ）. The crossing type of gratings with double-frequency （25001/mm and 50001/mm） using the focused ion beam （FIB） milling are successfully produced in a combination mode or superposition mode. Based on the double-frequency gratings, high-quality scanning electron microscopy （SEM） Moird patterns are obtained to study the micro-scale deformation of porous NiTi SMA. The grating fabrication technique is discussed in detail. The experimental results verify the feasibility of fabricating high frequency grating on metal surface using FIB milling.     

Modified Molecular Model for the Description of Condensed Phases of Heavy Water

JETP Letters - Using the lattice dynamics method, a simple three-point model of heavy water has been proposed by optimizing thermal expansion and the melting temperature of deuterated hexagonal ice...     

Semi-Classical Derivation of the Spin-Orbit Coupling for the Dirac Particle in an Accelerated Frame

We give a semi-classical derivation for the spin-orbit coupling in the non-relativistic Hamiltonian of the Dirac particle in an accelerated frame, in direct analogy with that for the Thomas term in the case of the electromagnetic interaction.     

Synthesis of Phenanthrene Alkaloids from Herbal Aporphine Alkaloids in Subcritical Water Using Synthesis of Seco-Glaucine as an Example

Transformation of the model aporphine alkaloid glaucine into the phenanthrene alkaloid secoglaucine (seco-GL) in subcritical water at 100–250°C without catalytic additives is studied. The maximum yield of seco-glaucine is achieved at 250°C. It is shown that under these conditions the load of the initial compound affects only slightly the yield of the target compound, which is on average 80%. The increase of the GL load up to 400 mg results in precipitation of the target seco-GL directly from the reaction mixture. The suggested method avoids the use of costly and toxic organic solvents.     

Development of an atom-interferometer gravity gradiometer for gravity measurement from space

Recent progress in cold atom interferometry has lead to a new method of sensitive inertial sensing. Significant performance enhancement of cold atom interferometer-based sensors is anticipated when operated in the microgravity environment in space. Based on cold atom interferometer techniques, we are developing a quantum gravity gradiometer for satellite-based global gravity field mapping. As a first step, we have built a laboratory-based gradiometer employing component technologies suitable for a future flight instrument. This paper describes the implementation of the laboratory instrument and its initial results. PACS 03.75.Dg; 39.20.+q; 32.80.Pj; 04.80.-y     

Solid Introduction to an ICP-Atomic Emission Spectrometer for the Analyses of Metals Contents of Air Filters

The direct introduction of solid samples (air filters) to the inductively coupled plasma source of an atomic emission spectrometer using a furnace atomizer has been studied. Conditions have been found for the analysis of elements which volatilize with varyling degrees of difficulty. Lead, copper and vandaium compounds retained on glass fibre filters from air pollution studies have been determined. The results are in good agreement with those obtained by means of established sample dissolution/atomic emision methods.     

刻蚀波导粗糙面散射的矩量法数值分析

用矩量法对刻蚀波导粗糙面的散射特性做出了精确的数值分析基于MonteCarlo方法建立高斯粗糙面数学模型,证明矩量法在分析刻蚀波导散射问题时,是可以应用于不同起伏高度、不同入射角的一种精确而高效的数值方法对不同起伏高度的两种偏振态,分别在小角度入射和大角度入射两种情况的随机散射特性应用矩量法做出了分析并以基于二氧化硅波导的EDG器件为例,分析了由于波导壁粗糙对于器件频谱响应特性的影响.     

Removal of redundancy from the single particle equation of motion method for odd mass nuclei

A method is developed for the removal of redundancy which is known to plague the calculation of low lying spectra of odd mass nuclei by the equation of motion method. The feasibility of the method is verified numerically.     

Development of an NMR Relaxometer for Determining Magnetization Dynamics of Water Protons in Living Tissues and Its Use for Evaluating Age-Related Changes

Technical Physics - A desktop NMR relaxometer was created, which allows determining spin–spin relaxation times of water protons in living tissues. Spin relaxation times of protons of water...     

Determination of the Parameters of Sea-Surface Roughness Using the Doppler Spectrum of a Microwave Radar Signal Reflected from a Water Surface

Within the framework of the Kirchhoff approximation, we derive formulas describing the shift and width of the Doppler spectrum of a microwave signal reflected from a rough water surface in the case of a small incidence angle. The formulas take into account the effect of the radar beam pattern. The new model of the spectrum allows for the fact that the distance from the radar to the observed surface changes in the course of measurements. Our theoretical analysis shows that the Doppler-spectrum parameters and the amount of information on the scattering surface, which is contained in the reflected signal, are strongly dependent on the antenna beamwidth. The results of our study allowed us to develop a new algorithm for measuring the water-surface parameters from a moving carrier.     

Verification of a New Model of the Irradiance Distribution from a Unidirectional Point Source in Water Using the Monte Carlo Method

Radiophysics and Quantum Electronics - We study the spatio-angular structure of a nonstationary light field produced in seawater by a unidirectional point source. The calculation results obtained...     

Interference Method for Estimating the Coordinates of a Moving Noise Source in Shallow Water Using High-Frequency Signals

Acoustical Physics - The article presents the results of a high-frequency experiment to localize a moving noise source using a cylindrical small-sized vector–scalar array....     

银纳米微粒荧光猝灭法测定水中痕量ClO2

在pH 9.1的NH4Cl-NH3·H2O缓冲溶液中,银纳米微粒在470 nm处产生一个荧光峰;它能被ClO2氧化导致体系的荧光发生猝灭.ClO2浓度在0.001 1～0.185μg·mL-1范围内与荧光猝灭强度成良好的线性关系,检测限为0.004 7μg·mL-1 ClO2.据此建立了测定ClO2的荧光分析新方法,用于饮用水中ClO2的测定,结果满意.     

Using optically stimulated electrons from quartz for the estimation of natural doses

A flow-through Geiger-Müller pancake electron detector attachment has been fitted to a standard Risø TL/OSL reader enabling optically stimulated electrons (OSE) to be measured simultaneously with optically stimulated luminescence (OSL). Using this detector, OSE and OSL measurements from natural quartz samples are studied to examine the possible use of OSE as a chronometer. First the relative variability in OSE and OSL growth curve shapes and the effect of preheat on these are presented, and from these curves, conclusions are drawn concerning the charge movement in natural quartz. Secondly, a dose recovery test shows that OSE can successfully recover a laboratory dose of 300 Gy given before any laboratory thermal treatment, for preheating temperatures between 160 and 260 °C. Furthermore, for the first time natural OSE decay curves are detected and these signals are used to estimate a burial dose using the single-aliquot regenerative-dose (SAR) procedure. Finally, a comparative study of the equivalent doses estimated using both OSE and OSL from 10 quartz samples are presented, and it is shown that OSE has a significant potential in retrospective dosimetry.