High-concentration aerosol is supposed to be crucial in some air pollution events. Aerosol always decays due to such mechanisms as coagulation, gravitational settling and diffusion deposition in a chamber; so its concentration needs to be calibrated in chamber experiments, especially for high-concentration aerosol. Two methods including the wall-loss correction and the direct simulation Monte Carlo (DSMC) were used to describe decay of the aerosol concentration. The parameters of diffusion deposition were fitted by experimental data. The results by both methods were compared to the experimental results of high-concentration aerosol decay process. The results show that the wall-loss correction under the present conditions is valid when the initial total aerosol concentration is less than 104 cm−3, and the DSMC results are consistent to the experimental data for concentration ranging from 104 cm−3 to more than 106 cm−3.

Suspicious aerosol samples need to be pretreated for detailed analysis in radionuclide monitoring proposed by the Comprehensive Nuclear-Test-Ban Treaty(CTBT).These samples are quite different from common aerosol samples since their filter matrix are massive and the number of analysed elements is large and their contents are very different.As a result,any single pretreatment method is not effective for recovering all radionuclides.A novel extraction-ashing-digestion method is proposed in this paper,including microwave extraction of volatilizable radionuclides,ashing of filter matrix and microwave digestion of difficultly soluble radionuclides.The spiked samples with polypropylene fibrous filter matrix were prepared.Natural abundance elements cesium,cerium and zirconium were selected as trace elements to validate the method.The recoveries under varied conditions such as pressure,power,duration time of microwave extraction,ashing temperature and time,as well as composition and concentration of microwave digestion reagents,were studied experimentally.The results show that cesium,cerium and zirconium in samples can be recovered completely under the optimum conditions.

The Direct Simulation Monte Carlo method(DSMC) is one of the popular numerical simulation methods for solving the General Dynamic Equation(GDE),a description of aerosol dynamics.Coagulation and Settling are usually the most important mechanisms in the GDE. A modified DSMC for simulation of simultaneous coagulation and settling is proposed to save the computation time.Its evaluation method based on the sectional method and self-preserved distribution is proposed in this paper.The results of simulations show that the time consumption of the DSMC method could be reduced by a factor of 100 and 1000 while running 1000 and 10000 particles respectively.And the results of the DSMC method are consistent with those of the sectional method.

Frequent filter clogging is the main problem for the aerosol samplers with more than 500 m3/h flowrate and installing pre-separators is a hopeful method to delay it.The style of cyclones used as pre-separators were discussed and consequently an uniflow cyclone with axial flow inlet was chosen.A method to estimate the cutoff diameters of the cyclones was deduced based on the principle of inertial separation.The test fig for performance was setup and three cyclones were manufactured and tested.The results showed that the cutoff diameters of the cyclones were 12～14.5 μm,consistent with the designed 15 μm.A cyclone with a cutoff diameter of 14.5 μm and penetration of 73% at 10 μm was recommended,which fulfilled the requirement.

A method of GC with pulse discharge helium ionization detector(PDHID) for the determination of krypton and xenon in air was proposed and the pressure adjustable installation for gas sample introduction was designed.The matrix interference of air was eliminated by low-temperature separation,temperature elevation programming of the column and the high efficiency getter column.Values of detection limit(3S/N) of krypton and xenon found were 11 pg and 24 pg,respectively.

A review on the progress of GC-ICP-MS applied to speciation analysis was presented covering mainly the years from 1987 to 2009,and pertaining especially to the topics on the design of hyphenation interface, kinds of GC,methods of sample preparation,as well as on the techniques of mass spectrometry in hyphenation of GC and ICP-MS.A brief discussion on the future prospects in this field was also given(61 ref.cited).

Extraction of Am(III) and Ln(III) from NaClO(4) medium has been investigated with di(2-ethylhexyl) dithiophosphoric acid, di(2-ethylhexyl) monothiophosphoric acid, di(2-ethylhexyl) monothiophosphinic acid, octylphenyl dithiophosphinic acid and I I kinds of dialkyl dithiophosphinic acids (alkyl = hexyl, heptyl, octyl, nonyl, 2-ethylhexyl, 1-methylheptyl, phenyl, chlorophenyl, methylphenyl, 2,5-dimethylphenyl, and 3,5-dichloro-4-methylphenyl) in xylene. The effect of chemical structures of those extractants on separation capability has been studied. The relationship between the slope value of the IgD-pH and extraction conditions call be described as: Ig S = a 1g(C(HA)/C(M)(S/4)) + b. In the presence of macro amounts of Eu(CIO(4))(3), the formula Ig SF(Am/Eu) = B - 2 lg (C(HL) - D(Eu)/ (D(Eu) + 1)C(Eu)), call well describe file relationship between separation factor and the extraction condition. A high separation factor (SF(Am/Eu) = 2500) is obtained by solvent extraction from 1 mnol/L NaNO(3), solution with 0.5 mol/L di(2-ethylhexyl) dithiophosphinic acid in toluene.

The relative response factors(RRFs) for noble gas(Ng) were determined on a pulsed discharge helium photoionization detector. Using ab initio method, the atomic orbitals of noble gas were calculated and used to determine the number of ionizable electrons on the basis of the continuous emission of He2. The molar responses of noble gases is well correlated with the number of ionizable electrons.

Extraction of Am(III) and Ln(III) from NaClO4 medium with di(2-ethylhexyl)dithiophosphoric acid (DEHDTP), di(2-ethylhexyl)monothiophosphoric acid (DEHMTP), di(2-ethylhexyl)monothiophosphinic acid (DEHMTPI), dihexyldithiophosphinic acid (DHXDTPI), diheptyldithiophosphinic acid (DHPDTPI), dioctyldithiophosphinic acids (DODTPI), dinonyldithiophosphinic acid (DNDTPI), di(1-methylheptyl)dithiophosphinic acid (DMHDTPI) and di(2-ethylhexyl)dithiophosphinic acid (DEHDTPI) in xylene has been investigated. The order of the extraction selectivity for Am(III) is DEHDTPI > DEHDTP > DEHMTPI > DEHMTP, DHPDTPI > DODTPI > DHXDTPI > DNDTPI, DMHDTPI > DEHDTPI > DODTPI, for extractants with 2-ethylhexyl alkyl, straight chain alkyl, branch chain alkyl, respectively. Using 0.1 mol/l NaClO4 solution as aqueous phase, the slope values of the logD-pH and logD-logC curves are not integers, and the slope values for Am(III) are slightly higher than those for Eu(III), for all extractants. The relationship between the slope value and extraction conditions can be described as: logS = alg(C HA/C M S/4)+b. In the presence of macro Eu(ClO4)3, the formula, logSF Am/Ln = B-2log(C HL-D Ln/(D Ln + 1)C Eu), can well describe the relationship between separation factor and the extraction condition. A high separation factor (SF Am/Eu = 2500) is obtained by solvent extraction with 0.5 mol/1 DEHDTPI in toluene from 1 mol/l NaNO3 solution.

Radionuclide verification is one of four international monitoring systems that were stipulated by the comprehensive nuclear test ban treaty.The radioactive noble gas xenon is a gaseous fission product of nuclear fuels.The radionuclides of Xe are characteristic nuclides of nuclear explosion.A nuclear event that violates the treaty may be found by monitoring the variation of radioxenon(mainly ~(133)Xe~(m),~(133)Xe,~(135)Xe and ~(131)Xe~(m)) in global atmosphere through a global network of eighty stations of the international monitoring system(IMS).Therefore,it is necessary to research the sampling technology for xenon isotopes.The possibilities for sampling technology(including condensation and concentration of xenon isotopes) is explored from pre-separating and pre-condensing(microxenon) sample with FNQ-01 gas condenser experimental platform.The collecting efficiencies of microxenon influenced by the different condensing conditions were studied on this experimental platform.The best condensing conditions optimized with the orthogonal design method are showed respectively as follows: xenon concentration in sample 1.046×10~(-3),condensing temperature-198 ℃,gas flow rate 0.3 L/min,gas inlet pressure 55 kPa and evaporating temperature-50 ℃.The average collecting efficiency under these optimized conditions is 73%.Furthermore,the influences of different admitting methods to xenon collecting efficiency and condensation were discussed.

The influences of some relevant parameters on resonance ionization efficiency in the recent laser pulse time-delayed scheme were analyzed with the framework of time-dependent Schrdinger equation.As a versatile example,the feasibility of this scheme applied to lutetium isotopic analysis by Laser Resonance ionization Spectrometry(LRIMS) was discussed.The results show that this scheme is infeasible for isotopic analysis utilizing broad-band lasers by LRIMS because the Rabi frequency between transition levels can not match well in the presence of hyperfine structures.On the base of theoretical analysis,the method combined this new scheme with narrow-band lasers excitation was presented in order that accurate isotopic ratio could be measured by LRIMS.

This paper introduces the method of dating the zero time by utilizing the activity ratio of two fission products in no-isobaric or parent-daughter fission products in isobaric. The method was applied to determine the zero time of filter sample in the CTBT radionuclide laboratories intercomparison from 2001 to 2004. The calculated results are in very good agreement with referent values in the range of uncertainty.

The effects of concentration of extractant (0.05 mol/L, 0.1 mol/L, 0.15 mol/L), pH (3.08, 3.14, 3.2) and the flow rate of mobile phase (0.25 mL/min, 0.5 mol/L, 0.75 mol/L) on the separation efficiency of Am and Eu by high speed countercurrent chromatography (HSCCC) were investigated using dichlorophenyldithiophosphinic acid in xylene as the stationary phase and 0.1 mol/L NaClO4 as mobile phase. The results show that the separation factor increases with the increasing of the concentration of extractant and the pH value of the mobile phase, furthermore, minishing the flow rate of the mobile phase can also improves the separation efficiency between Am and Eu. Mutual separation between Am3+ and Eu3+ can be accomplished Eu3+ by optimizing the separation condition, the separation factor and separation efficiency between Am3+ and Eu3+ can reach 2.87 and 0.74, respectively.

The high-purity nitric acid and hydrochloric acid were prepared by high-speed countercurrent chromatography(HSCCC), using the 0.25 mol/L tri-octyl-phosphorous oxide in heptane as the stationary phase, and the normal nitric acid and hydrochloric acid were used as mobile phase. The results show that the uranium contained in the acid purified is reduced to lower than 1 pg/mL, which is close to the content of uranium in the high-purity water and the high-purity acid prepared by isothermal evaporation and sub-boil distillation.

Technique of lutetium isotopic analysis by laser resonance ionization mass spectrometry(LRIMS) was developed in the presence of isobaric interference. In the case of real sample, the elemental selectivity was better than 8×105, and the detection efficiency was 8.3×10-5. The technique of wavelength scanning method was set up in order that the accurate isotopic ratio could be determined. And the numerical computational method was provided to calculate the correct factor of isotopic ratio. Using this technique, the isotopic ratio measured by LRIMS is in good agreement with standard value measured by TIMS.

An experimental sampler for rare gases (ESRG) which can collect radioxenon isotopes from atmosphere under normal temperature and low temperature is installed and studied. Its sampling efficiency is calibrated with ICP-MS (Inductively Coupled Plasma-Mass Spectrum) through analyzing the ~129Xe in the off-gas of ESRG. The main experimental results show that the sampling efficiency to xenon isotopes in ambient air is up to 40% when the adsorbent is effectually regenerated.