SPM analysis on groups of single aerosol particles around steel plant

Several methods for preparing samples of dispersed single aeroslo particles used in scanning proton microprobe(SPM) analysis were tested.Many elements such as Al,Si,S,Cl,Ca,Ti,Cr,Mn,Fe,Ni,Cu and Zn in the groups of different single aerosol particles from the Capital Steel Plant area were analyzed by SPM,The distributions of elemental contents in the group of single particles were mapped with three dimensional contour and the isometric.A new approach to study the group of different single aerosol particles for air pollution is developed in the present work.The results are significant to assessing the environmental impact of the dispersed single aerosol particles.     

Application of nuclear analytical techniques to trace elements in Cenozoic basalt and their mantle xenoliths from Aershan area in Inner Mongolia, China

Basaltic samples from different locations in Aershan area determined by instrumental neutron activation analysis (INAA) have the same distribution patterns of REE and trace elements. The similar REE contents of the same minerals without inclusions from different xenolith suggest that the mantle source region under different active volcanoes have the same composition. The REE content differences between the same minerals with and without melt inclusions selected from the same mantle xenolith indicate that the melt inclusions are rich in REE. The same patterns of trace elements of inclusions and host minerals from different xenolith analyzed by SRXRF suggest that the mantle fluid has no notable heterogeneity in Aershan area.     

Roadside dust contamination with toxic metals along industrial area in Islamabad,Pakistan

An investigation has been carried out to understand the contamination characteristics of roadside dust in the industrial area of Islamabad, Pakistan. The amounts of Si, S, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Pb, Zn, Ga, As, Se and Cd were determined from 95 roadside dust samples collected along the Islamabad industrial area using Proton Induced X-ray Emission （PIXE）. The results indicated that concentrations of all elements, except Cd, in the roadside dust were significant. The results of the enrichment factor show that the elementary composition of the roadside dust could be categorized as soil elements from the crust of the earth and elements from anthropogenic pollution. The high enrichment factors imply that elements such Cr, Cu, Pb, Zn, As, Se, Cd, Ni, Co and S came from anthropogenic activities. The source of metal contamination was identified using multivariate statistical analysis. It has been concluded that Ca, Sc, Ti, V, Mn and Fe mainly originate from crustal sources; Cr, Cu, Ni, Pb, Zn and Ga are associated with point-sources from industrial pollution/traffic; and S, Cl, K, As and Se are mainly related to oil/coal combustion.     

Boundary Effect of Planar Glow Dielectric Barrier Discharge and Its Influence on the Discharge Structure

The dielectric barrier discharge(DBD) in the glow regime in neon has been investigated by experiment and two-dimensional(2D) fluid modeling.The discharge was carried out in a planar DBD system with segmented-electrodes driven by square-wave voltage.The results show that the glow DBD originates in the center of the electrode and expands outward to the electrode edge during each half cycle of the voltage,forming a radial structure.The discharge decays firstly in the inner area but sustains longer in the edge area,showing a reversed discharge area.The discharge cannot completely cover the entire electrode surface,but remains a border of non- or weak discharge.The fluid modeling shows a similar result in agreement with the experiments.The simulations indicate that the electric field in the edge area is distorted due to the boundary effect so that the electric field and charge distribution are different from that in the inner part.The distorted field reduces the longitudinal component near the edge and causes the local field to be lower than that in the center,and hence makes the discharge behindhand.It also induces a transverse field that makes the discharge extend radially outward to the edge.The boundary effect plays an important role in the glow DBD structure.     

Activity level of gross α and gross β in airborne aerosol samples around the Qinshan NPP

The monitoring results of gross α and gross β activity from 2001 to 2005 for environmental airborne aerosol samples around the Qinshan NPP base are presented in this paper. A total of 170 aerosol samples were collected from monitoring sites of Caichenmen village, Qinlian village, Xiajiawan village and Yangliucun village around the Qinshan NPP base. The measured specific activity of gross α and gross β are in the range of 0.02 ～ 0.38 mBq/m3 and 0.10 ～ 1.81 mBq/m3, respectively, with an average of 0.11 mBq/m3 and 0.45mBq/m3, respectively. They are lower than the average of 0.15 mBq/m3 and 0.52mBq/m3, of reference site at Hangzhou City. It is indicated that the specific activity of gross α and gross β for environmental aerosol samples around the Qinshan NPP base had not been increased in normal operating conditions of the NPP.     

A NEW EXX SYSTEM AND ITS APPLICATIONS

IXX (or PIXE-induced XRF) technique gains two main advantages over conventional PIXE method. First, it can be used to avoid or significantly reduce background and spectral interferences from major elements in the sample by proper selecting the primary target. Second, target damage is greatly reduced, so that it is more suitable for the analysis of heatsensitive and delicate specimens. A new IXX system with a very tight geometry is described. Some of its performances and preliminary applications are presented.     

Thermodynamic Characteristics of Dusty Plasma Studied by Using Molecular Dynamics Simulation

Thermodynamic properties of a Debye-Yukawa system of particles are explored by using molecular dynamics simulation in the canonical ensemble.The excess free energy f of the Debye-Yukawa system is calculated by using two different approaches for the liquid phase,and the energy is obtained in a coupling parameter range of 0≤Γ≤100 and a wide range of the screening parameter κ.Simulation measurements for excess internal energy and pressure of the system over dimensionless parameters (κ,Γ) are also presented and compared with previous theoretical and simulated results.A Γ-expansion-fitting approach for the liquid phase is introduced with the expansion coefficients,which are functions of the screening parameter κ.The fitting coefficients are obtained by directly comparing them with the simulation measurements with a relative deviation of 1% or less.It is shown that the computational results provide a relatively simple method to calculate the excess internal energy and free energy in certain cases,which depend strongly on.     

The Gas Nucleation Process Study of Anatase TiO2 in Atmospheric Non-Thermal Plasma EnhancedChemical Vapor Deposition简

Abstract The gas phase nucleation process of anatase TiO2 in atmospheric non-thermal plasma enhanced chemical vapor deposition is studied. The particles synthesized in the plasma gas phase at different power density were collected outside of the reactor. The structure of the collected particles has been investigated by field scanning electron microscope （FESEM）, X-ray diffraction （XRD）, high resolution transmission electron microscopy （HRTEM） and selected area electron diffraction （SAED）. The analysis shows that uniform crystalline nuclei with average size of several nanometers have been formed in the scale of micro second through this reactive atmo- spheric plasma gas process. The crystallinity of the nanoparticles increases with power density. The high density of crystalline nanonuclei in the plasma gas phase and the low gas temperature are beneficial to the fast deposition of the 3D porous anatase TiO2 film.     

Radiolytic organics in γ-ray irradiated aqueous solution of N,N-diethylhydroxylamine

N,N-diethylhydroxylamine (DEHA) is a novel salt-free reducing agent used in separating Pu and Np from U in the reprocessing of spent nuclear fuel.In this paper,we report the study on γ-radiolysis of DEHA in water and its radiolytic liquid organics by gas chromatography.The radiolysis rate of DEHA increases with the absorbed dose,but decreases with the primary DEHA concentration at 0.1-0.5 mol?L-1 irradiated to 10-1000 kGy.The main organics produced in radiolysis of DEHA are acetaldehyde,acetic acid and ethanol.The concentration of acetaldehyde increases with the primary DEHA concentration and the absorbed dose at ≤500 kGy,but over 500 kGy it decreases with increasing dose.The dependence of the concentration of acetic acid on the absorbed dose is similar to that of acetaldehyde,with a lower turning point of the dose,though.The ethanol concentration changes differently among the irradiated samples of different primary DEHA concentrations,and this is discussed.The maximum concentrations of acetaldehyde,acetic acid and ethanol are 0.029,0.014 and 0.028 mol·L-1,respectively.     

Studies of Wettability of Medical PVC by Remote Nitrogen Plasma

The effects of remote nitrogen plasma and nitrogen plasma on medical PVC＇s surface modification are studied. The surface properties are characterized by the contact angle measurement, X-ray photoelectron spectroscopy and scanning electron microscopy. Results show that the remote nitrogen plasma treatments modify the PVC surface in both morphology and composition and the treatment by the remote nitrogen plasma in PVC surface modification is more effective than that by the nitrogen plasma. Remote nitrogen plasma can modify the surface more uniformly. After the PVC surface is treated for 2 man by remote nitrogen plasma, the [w（O）＋ w （N）]/w （C）] value increases from 0.13 to 0.51 and the water contact angle decreases from 89° to 18 .     

Radioactivity levels in soil of salt field area,Kelambakkam,Tamilnadu,India

Soil samples in and around salt field area have been analyzed for natural radioactivity concentration using gamma ray spectrometer.The activity concentration for ~(232)Th,~(238)U and ~(40)K are ranged from 27.88 to 45.27 Bq/kg, from BDL to 13.30 Bq/kg,and from 135.54 to 381.28 Bq/kg,respectively.The measured activity concentrations for these radionuclides were compared with world average activity of soil.The average activity concentration of ~(232)Th in the present study is 1.19 times higher than world median value while the activity of ~(238)U and ~(40)K is found to be lower. The absorbed dose rates due to these radionuclides were calculated.The average absorbed gamma dose rate due to the presence of ~(232)Th,~(238)U and ~(40)K in soil samples is 36.99 nGy·h~(-1).These results indicate no radiological anomaly. The data presented in this study will serve as a base line survey for primordial radionuclides concentration in the study area.     

TRANSPORT OF RADIONUCLIDES ALONG MARINE FOODCHAIN

A compartment model is employed to calculate the radionuclide concentrations in the ocean currents for a nuclear accient scenario where the long-lived 137 Cs is totally discharged into the sea.The radionuclide concentrations in both the waters of Daya Bay and the adjacent south China Sea are considered.Using the concentration factors for the marine organisms:fish,crustacea and mollusca,their radionuclide concentrations are also estimated.In this way,the whole body radiation doses received by an individual due to ingestion of marine organisms from the Daya Bay and the South China Sea are calculated.     

Multi-technique characterizations of main elements in the vehicle exhaust particles collected in a tunnel in Shnaghai

In this study,vehicle exhaust particles were collected three locations (the middle,entrance and outside) of the Dapu Road tunnel in downtown Shanghai,and the particle samples were characterized using SEM,XAFS,ICP-MS and M?ssbauer spectrometry,and the oxidative damage was assessed by plasmid DNA.Most iron-containing particles are found from vehicle exhaust,and iron oxide is the major species in all samples.Its concentration in the particles inside the tunnel is higher than that the outside particles.The iron particles inside the tunnel have higher proportion of water-soluble fraction in hydrous iron sulfate form or smaller size.ZnCl2 is the main soluble fraction in zinc-containing particles,while higher percentage of insoluble fraction existed in the particles outside of tunnel.Major species of lead-containing particles are PbSO4,Pb3(PO4)2 and PbCO3.In addition,the soluble fraction of other transition metallic elements as Ti and V is higher in the particles inside the tunnel than that outside the tunnel.The plasmid DNA assay results indicate that the particles from vehicle exhaust have a stronger oxidative damage and inflammation than that from outside of the tunnel.     

PIC-MC Code to Model Fast Electron Beam Transport Through Dense Matter

A PIC （particle-in-cell）-MC （Monte Carlo） code to model electron beam transport into dense matter is developed. The background target is treated as a cold, stationary fluid and the fast electrons as particles with the relativistic motions. The process is described by a particle-in-cell method with consideration of the influence of both the self-generated electric and magnetic fields as well as collisions between the fast electrons and the target. The collisional part of the code is solved by the Monte Carlo-type method. Furthermore by assuming that the background current balances with the fast electron current, the electric field is given by the Ohm＇s law and the magnetic field is calculated from the Faraday＇s law. Both are solved in a two-dimensional cylindrical geometry. The algorithms implemented in the code are demonstrated and the numerical experiments are performed for monoenergy homogeneous fast electron beam transport in an aluminum target when the fields, collision and angular scattering are switched on and off independently.     

Remote open-path laser-induced breakdown spectroscopy for the analysis of manganese in steel samples at high temperature

A remote open-path laser-induced breakdown spectroscopy(LIBS) system was designed and studied in the present work for the purpose of combining the LIBS technique with the steel production line. In this system, the relatively simple configuration and optics were employed to measure the steel samples at a remote distance and a hot sample temperature. The system has obtained a robustness for the deviation of the sample position because of the open-path and alloptical structure. The measurement was carried out at different sample temperatures by placing the samples in a muffle furnace with a window in the front door. The results show that the intensity of the spectral lines increased as the sample temperature increased. The influence of the sample temperature on the quantitative analysis of manganese in the steel samples was investigated by measuring ten standard steel samples at different temperatures. Three samples were selected as the test sample for the simulation measurement. The results show that, at the sample temperature of 500 ℃, the average relative error of prediction is 3.1% and the average relative standard deviation is 7.7%, respectively.     

Effects of nitrogen on ozone synthesis in packed-bed dielectric barrier discharge

The effects of nitrogen on ozone synthesis are studied in a coaxial cylinder generator with dielectric barrier discharge (DBD) and pack-bed dielectric barrier discharge (PB-DBD). A series of 10 h discharge experiments are conducted adopting a bare stainless electrode and bare copper electrode. Results show that the material of the electrode can affect the ozone synthesis. It is inferred that the ozone zero phenomenon (OZP) may be induced from ozone decomposing by metallic oxide catalysis. Packing dielectric particles can reduce the OZP. Adding a certain amount of nitrogen into the oxygen feed gas can further eliminate the OZP, and increase the ozone concentration significantly, but decreases the maximum energy efficiency of ozone generators. Initial analysis indicates that the optimal proportion of nitrogen addition is inversely related to the average reduced electric field strength in the discharge region.     

Measuring energy loss of alpha particles in different vacuum conditions

In this paper,energy loss of alpha particles in different vacuum levels is studied experimentally and via theoretical analysis.A better understanding of energy loss of a particle in vacuum will help detect more exact numbers of alpha particles.Two ²³⁹Pu sources are used to measure the energy loss of a particle crossing different vacuum levels （different air pressures）.The experimental data are obtained from an instrument-PAM-100 developed by authors. The experimental results have shown that increasing vacuum levels will lead to more alpha residual energy but less energy loss.When the vacuum level reaches 0.04 MPa,alpha particles(²³⁹Pu,5.115 MeV)will lose the energy of about 0.175 MeV with traversing 5 mm distance.Theoretical calculations have shown a good agreement with experimental results.This implies that the instrument has a high accuracy and could be applied in field work.     

Trace elements in particles of motor vehicle exhaust in Shanghai

A nuclear microprobe with high spatial resolution and high analytical sensitivity was applied to analyze trace elements,especially lead,in vehicle exhaust of Shanghai city.The result shows that the chemical composition and its corresponding x-ray relative intensity are different among different vehicle exhausts.There are many kinds of metal elements in particles of vehicle exhaust.most are harmful to people,such as Ti,Cr,Mn,Pb,etc.We found that the lead concentration was 6820μg/g and the bromine concentration was 5300μg/g in the exhaust from Santana using leaded gasoline(SULG).which is higher than any other kinds of vehicle exhausts.We have also detected the minimum lead in the particles of unleaded gasoline and its content varies from one to another.Its mean concentration was 450μg/g and the highest reached 6210μg/g.The unleaded gasoline‘s Pb existed in the whole particle while the leaded gasoline‘s enriched in the surface of the particle and was more harmful to the human beings.     

Preparation of Standard γ Ray Source for Aerosol Membrane

正In the process of environmental radiation monitoring,it is necessary to analyze radionuclides in the aerosol.Analysis of radionuclides in aerosols is usually adopted by γ spectrometry method.The method comprises the following steps:First by make the aerosol particles in the atmosphere through filter PP or glass fiber using     

Axial Magnetic Field Effects on Xenon Short-Arc Lamps

The effect of an axial magnetic field （AMF） on an old xenon short-arc lamp is experimentally investigated in this work. As the AMF increases up to 18 roT, the visible radiation power and electric power ascend more than 80% and 70% respectively, and the radiation efficiency is improved by 23% for the best increment at 12 mT AMF. The measurement of radiation intensity shows that the increment of radiation intensity comes mostly from the plasma area close to the cathode tip, and partially from the other area of the arc column. Successive images of the arc indicate that the arc column not only rotates about its axis, but revolves around the axis of electrodes with the AMF. The arc column structure is constricted, distorted and elongated as the AMF increases. It is suggested that the improvements of the radiation intensity and radiation efficiency are attributed to the constriction of the arc column, which is mainly induced by the enhanced cathode jet.