周期为p 7(mod 8)的一类新六次剩余序列的迹表示

构造了一类新的周期为素数 的六次剩余序列，利用有限域和差集理论给出了该序列在周期为素数 情形下的迹函数表示。新序列的线性复杂度为 ，优于Hall六次剩余序列在相同条件下的线性复杂度。     

Trace element load in cancer and normal lung tissue

Samples of malignant and benign human lung tissues were analysed by two complementary methods, i.e., particle induced X-ray emission (PIXE) and total reflection X-ray fluorescence (TRXRF). The concentration of trace elements of P, S, K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Se, Sr, Hg and Pb was determined in squamous cancer of lung tissue from 65 people and in the benign lung tumour tissue from 5 people. Several elements shows enhancement in cancerous lung tissue of women in comparison to men, i.e., titanium show maximum enhancement by 48% followed by Cr (20%) and Mn (36%). At the same time trace element concentration of Sr and Pb are declaimed by 30% and 20% in women population. Physical basis of used analytical methods, experimental set-up and the procedure of sample preparation are described.     

Aerosol composition and source apportionment in Santiago de Chile

Santiago de Chile, São Paulo and Mexico City are Latin American urban areas that suffer from heavy air pollution. In order to study air pollution in Santiago area, an aerosol source apportionment study was designed to measure ambient aerosol composition and size distribution for two downtown sampling sites in Santiago. The aerosol monitoring stations were operated in Gotuzo and Las Condes during July and August 1996. The study employed stacked filter units (SFU) for aerosol sampling, collecting fine mode aerosol (dp<2 μm) and coarse mode aerosol (210 mass of particles smaller than 10 μm) and black carbon concentration were also measured. Particle-Induced X-ray Emission (PIXE) was used to measure the concentration of 22 trace elements at levels below 0.5 ng m⁻³. Quantitative aerosol source apportionment was performed using Absolute Principal Factor Analysis (APFA). Very high aerosol concentrations were observed (up to 400 μg/m³ PM₁₀). The main aerosol particle sources in Santiago are resuspended soil dust and traffic emissions. Coarse particles account for 63% of PM₁₀ aerosol in Gotuzo and 53% in Las Condes. A major part of this component is resuspended soil dust. In the fine fraction, resuspended soil dust accounts for 15% of fine mass, and the aerosols associated with transportation activities account for a high 64% of the fine particle mass. Sulfate particle is an important component of the aerosol in Santiago, mainly originating from gas-to-particle conversion from SO₂. In the Gotuzo site, sulfates are the highest aerosol component, accounting for 64.5% of fine mass. Direct traffic emissions are generally mixed with resuspended soil dust. It is difficult to separate the two components, because the soil dust in downtown Santiago is contaminated with Pb, Br, Cl, and other heavy metals that are also tracers for traffic emissions. Residual oil combustion is observed, with the presence of V, S and Ni. An aerosol components from industrial emissions is also present, with the presence of several heavy metals such as Zn, Cu and others. A factor with molybdenum, arsenic, copper and sulfur was observed frequently, and it results from emissions of copper smelters.     

Determination of trace selenium on hanging copper amalgam drop electrode

Hanging copper amalgam drop electrode has been applied for trace determination of selenium by cathodic stripping analysis. Detection limit for Se(IV) as low as 0.25 nM (0.02 μg L⁻¹) at deposition time (120 s) could be obtained. For seven successive determinations of Se(IV) at concentration of 5 nM relative standard deviation was 2.3% (n = 7). Interferences from selected metals and surfactant substances were examined. Absence of copper ions in sample solution causes easier optimization and makes method less vulnerable on contamination. The developed method was validated by analysis of certified reference materials (BCRs) and applied to selenium determinations in natural water samples, snow, mushrooms and ox liver.     

Hybrid PAC-submerged membrane system for trace organics removal: I. Adsorption kinetics study of PAC in a bubbled solution

Part I of this study presents a theoretical method combined with experiments to determine the adsorption kinetics of powdered activated carbon (PAC) in the hybrid PAC-submerged membrane (SM) system with air bubbling for trace organics removal. The homogeneous surface diffusion model (HSDM) was applied to describe the kinetics of the adsorbate uptake. The differences between the model solutions and the corresponding experimental results were minimized by means of Levenberg–Marquardt algorithm so that two kinetic parameters D_S and k_f involved in HSDM were obtained simultaneously. The D_S was found to be 1.14 × 10⁻¹⁶ m²/s and the k_f value was correlated with the bubbling rate (Q_b) and carbon dosage (C_c), which are required in the modeling of the hybrid PAC-SM system presented in Part II of this study. The k_f was enhanced from 1.18 × 10⁻⁴ to 4.18 × 10⁻⁴ m/s when the bubbling intensity increased in the intermittent bubbling tests, suggesting that from energy consumption point of view, the high intensity intermittent bubbling is more efficient in improving the liquid film mass transfer than continuous bubbling with the same net bubbling rate.     

Element concentrations in shell of Pinctada margaritifera from French Polynesia and evaluation for using as a food supplement

Element concentrations in shell of Pinctada margaritifera (black-lip pearl oyster) from Manihi, French Polynesia, were measured with Inductively Coupled Plasma – Atomic Emission Spectrometry (ICP-AES). The respective average concentrations were: calcium (Ca) 396.4 mg/g, sodium (Na) 5.536 mg/g, magnesium (Mg) 2.136 mg/g, strontium (Sr) 890.6 ppm, iron (Fe) 67.89 ppm, aluminum (Al) 45.74 ppm, phosphorus (P) 27.19 ppm, boron (B) 12.17 ppm, manganese (Mn) 2.308 ppm, copper (Cu) 1.050 ppm, zinc (Zn) 0.7180 ppm; and nickel (Ni), chromium (Cr), mercury (Hg), arsenic (As), cadmium (Cd), lead (Pb), and vanadium (V) were below detection limits with ICP-AES.     

数据模式压缩的处理方法

本文利用迹函数研究数据模式的压缩问题，由问题ｍａｘＵＴＵ＝ＩｄＴｒ（ＵＴＳｂＵ）Ｔｒ（ＵＴＳｗＵ）或问题ｍａｘＵＴＵ＝ＩｄＴｒ［（ＵＴＳｗＵ）－１（ＵＴＳｂＵ）］的解Ｕ０实现数据模式Ｘ的压缩Ｙ＝ＸＵ０．     

氢化物原子吸收法测定铀水冶厂外排废水中痕量砷

在硫酸介质中,用碘化钾-硫脲将砷(Ⅴ)还原成砷(Ⅲ),用硼氢化钠将砷(Ⅲ)还原为砷化氢气体,借氮气将砷化氢载入石英原子化器,于920℃进行原子化。用国产仪器和砷空心阴极灯进行原子吸收测量。方法灵敏度为0.2纳克/毫升(1％吸收);相对标准偏差≤10％;回收率88—103％。