Mantle metasomatism for metaperidotite from Shuanggou ophiolite of Yunnan Province by proton microprobe

This study shows that olivine,serpentine and orthopyroxene are enriched with compatible element Ni;clinopyroxene with Ni and Y;spinel strongly with Ni,Zn,Ga,Ge,As and Zr;chlorite with Ni,Zn,Sr and Zr,However,grossulatrite is poor in all of these trace elements,except Sr.The trace element composition and distribution in the minearls are heterogeneous.The distributions of trace elements in the minerals further demonstrate that they result from mantle metasomatism under open system.     

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.     

Synchrotron radiation X-ray fluorescence analysis on altered mineral muscovite in gold deposit

Synchrotron radiation X-ray fluorescence (SRXRF) microprobe was used to ananlyse altered mineral muscovite and its surrounding feldspar in Yuerya gold deposit. The major, minor and trace elements of the two minerals were detected and analyzed. SRXRF analysis showed that the Yuerya muscovite had a complex chemical composition. containing K, Fe, Ca, Ti, Cr, Mn, Co, Cu, Zn and many trace or ultra-trace elements. Since muscovite resulted from the alteration of hydrothermal ore fluid acting on feldspar (plagioclase), the difference of chemical composition between the two minerals shows the components of ore fluid, which are characterized by the enrichment of alkaline and alkaline-earth metal elements K, Ca and ore-associated elements Fe, Cu, Zn. And gold. silver and platinum, invisible under microscope, were detected in some areas of muscovite but not found in feldspar. Especially platinum, a mantle material is rarely seen in the earth crust but now found in the gold deposit of magmatic sources; its appearance approves the idea of mantle flux participating in the gold mineralization, which suggests that the tectonic event controlling gold mineralization in the Yuerya district is a mantle phenomenon.     

TRACE ELEMENT CHARACTERISTICS OF ULTRAMAFIC INCLUSIONS IN THE EASTERN PART OF LIAONING-JILIN PROVINCES BY NAA

Cenozoic basalts in the eastern part of Liaoning-Jilin contain abundant mantle-derived inclusions. The rock types of the ultramafic inclusions are composed mostly of spinel lherzolite and a few websterites. In order to study the origin of inclusions, the concnetrations of several trace elements have been measured in samples by NAA. According to geochemical characteristics of trace elements, there are two types of spinel Iherzolite inclusions. The first type is refractory residues left after partial melting of the upper mantle and the second type is metasomatizing refractory residues. The websterites inclusions formed by segregation of basaltic melt derived from high degree of melting of mantle source rocks.     

STUDY ON OCCURENCE FORM OF PLATINUM IN XINJIE Cu—Pt DEPOSIT BY NAA AND SCANNING PROTON MICROPROBE

A combination of NAA and micro-PIXE was used to study concentrations and distributions of platinum group elements (PGE) in ores from Xinjie Cu-Pt deposit.The NAA results of the bulk indicate that the ores belong to the enriched Pt-Pd type.The element concentration maps of scanning micro-PIXE for the ores show that the occurence form of Pt is independent arsenide minerals.No PGE were detected in chalcopyrite of Xinjie Cu-Pt deposit.These information are economically beneficial to the mineral smelting process.     

PIXE ANALYSIS OF GRAPHITE PHASE IN NODULAR CAST IRON

The graphite phase has been extracted from the nodular cast iron to measure the concentration of trace element in it. The impurity phase was removed from the extracted matter by dissolving it with HCl and HCl+H_2O_2 to get the pure graphite phase. PIXE measurements were performed with thick targets of the pure graphite phase. Differences in the trace element concentrations between the graphite phase and the matrix have been observed. The effect of Ti and As in graphite phase on the nodularization rate and the mechanical properties have been studied.     

INVESTIGATION ON TRACE ELEMENTS IN CRUDE OILS AND ORGANIC MATERIALS EXTRACTED FROM OIL-FORMING SOURCE ROCKS IN CHINA WITH INAA

A combination of Soxhlet extraction, column chromatography and INAA with GC and GC- MS was used in this work for the study of the abundance patterns of 36 trace elements and their correlation in nearly 100 samples of crude oil and organic materials extracted from oil- forming source rocks from 10 main Chinese oilfields. The low V/Ni ratios of 0.01 to 0.3 state the oil- forming continent environment. The geochemical significance hinted from other trace element abundances is also briefly discussed.     

A STUDY OF ANTINODULARIZING PROPERTIES OF Pb, Bi, Al AND Ti IN NODULAR CAST IRON BY SPM

The nodular cast iron samples were prepared with the normal nodularizing process, in which the important antinodularizing elements Pb, Bi and Al were added respectively in order to research the influence of them on the nodularization of the graphites. The nodular graphites were extracted from the nodular cast iron by the electrolytic technique. The distribution of trace elements in nodular and deformed graphite were measured by Scanning Proton Microprobe (SPM). Most of the adding elements Pb, Bi and Al existed in matrix as impurities, a part of them intruded into the nodular graphites. A new suggestion of Ti antinodularizing properties had been proposed. The influence of Pb, Bi and Al on the nodularization was indirectly performed through Ti. Therefore, Ti is one of the most important antinodularizing elements.     

GEOCHEMICAL CHARACTERISTICS OF VOLCANIC ROCKS FROM TANGBALE OPHIOLITE IN THE WESTERN JUNGGAR OF XINJIANG

An INAA technique was applied to determine simultaneously abundances of rare-earth, transitional metal, large-ion lithophile and high field strength elements in volcanic rocks from Tangbale ophiolite belt. The detailed study on trace element geochemistry shows that the volcanic rocks were erupted in the back-arc basin. The volcanic rocks of early and middle stages of the expanding period of the basin have low REE and other incompatible element contents. At early and late stages of closing period of the basin, alkalic basalts, basaltic andesites and andesites were erupted in which light REE and other incompatible elements were enriched.     

Study of talcum charging status in parallel plate electrostatic separator based on particle trajectory analysis

Electrostatic separation has been extensively used in mineral processing, and has the potential to separate gangue minerals from raw talcum ore. As for electrostatic separation, the particle charging status is one of important influence factors. To describe the talcum particle charging status in a parallel plate electrostatic separator accurately, this paper proposes a modern images processing method. Based on the actual trajectories obtained from sequence images of particle movement and the analysis of physical forces applied on a charged particle, a numerical model is built, which could calculate the charge-to-mass ratios represented as the charging status of particle and simulate the particle trajectories. The simulated trajectories agree well with the experimental results obtained by images processing. In addition, chemical composition analysis is employed to reveal the relationship between ferrum gangue mineral content and charge-tomass ratios. Research results show that the proposed method is effective for describing the particle charging status in electrostatic separation.     

Stability of Nitrous Acid in TBP/OK

<正>According to the high distribution ratio of nitrous acid in TBP,it will be extracted into organic phase with uranium and plutonium in 1A extraction process.If the concentration of nitrous acid is too high,it will severely affect the routine processing of 1B unit because of the reaction with reductant.It is necessary to study on the stability of nitrous acid in TBP/OK to guarantee the accuracy and timeliness of results acid because nitrous acid is unstable.     

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.     

Stress and Thermal Analysis of the In-Vessel Resonant Magnetic Perturbation Coils on the J-TEXT Tokamak

A set of four in-vessel saddle coils was designed to generate a helical field on the J-TEXT tokamak to study the influences of the external perturbation field on plasma. The coils are fed with alternating current up to 10 kA at frequency up to 10 kHz. Due to the special structure, complex thermal environment and limited space in the vacuum chamber, it is very important to make sure that the coils will not be damaged when undergoing the huge electromagnetic forces in the strong toroidal field, and that their temperatures don’t rise too much and destroy the insulation. A 3D finite element model is developed in this paper using the ANSYS code, stresses are analyzed to find the worst condition, and a mounting method is then established. The results of the stress and modal analyses show that the mounting method meets the strength requirements. Finally, a thermal analysis is performed to study the cooling process and the temperature distribution of the coils.     

Elemental analysis of rain－and fresh water by neutron activation analysis

Analysis of rain-and fresh water for trace constitutents is a mandatory part of environmental monitoring.This text gives a survey of neutron activation analysis(NAA) within the framework of current environmental water research programmes.based on the practice developed in co-operation with the Dutch Energy Research Centre at Petten(ECN).While the procedures reported in literature cover obout thirty five elements,our routine procedures of instrumental neutron activation analysis(INAA) is limited to ten to fifteen elements.THe use of some dedicated radiochemical separations(RNAA) adds another six,some of which are speciated as well.Current contributions of NAA to water analysis center on determination and speciation of anionic trace elements,notably Br.I,As,and Se,on the assay of some ultra traces like Ag,Au and Hg and on validation.     

Chemical Form of Selection for ~(79)Se Measurement With AMS

79Se is a long-lived radionuclide which is produced from nuclear waste, and the half-life is (2.80±0.40)×105 a. Recently, owing to the potential implications of Se in the field of biomedical research and environment science research, measuring the content of the trace element79Se in the biological     

Numerical Study on Arc Plasma Behavior During Arc Commutation Process in Direct Current Circuit Breaker

This paper focuses on the numerical investigation of arc plasma behavior during arc commutation process in a medium-voltage direct current circuit breaker(DCCB) contact system.A three-dimensional magneto-hydrodynamic(MHD) model of air arc plasma in the contact system of a DCCB is developed,based on commercial software FLUENT.Coupled electromagnetic and gas dynamic interactions are considered as usual,and a thin layer of nonlinear electrical resistance elements is used to represent the voltage drop of plasma sheath and the formation of new arc root.The distributions of pressure,temperature,gas flow and current density of arc plasma in arc region are calculated.The simulation results indicate that the pressure distribution related to the contact system has a strong effect on the arc commutation process,arising from the change of electrical conductivity in the arc root region.In DCCB contact system,the pressure of arc root region will be concentrated and higher if the space above the moving contact is enclosed,which is not good for arc root commutation.However,when the region is opened,the pressure distribution would be lower and more evenly,which is favorable for the arc root commutation.     

Numerical analysis on element creation by nuclear transmutation of fission products

A burnup calculation was performed to analyze the Apr`es ORIENT process, which aims to create highlyvaluable elements from fission products separated from spent nuclear fuels. The basic idea is to use nuclear transmutation induced by a neutron capture reaction followed by a β-decay, thus changing the atomic number Z of a target element in fission products by 1 unit. LWR(PWR) and FBR(MONJU) were considered as the transmutation devices. High rates of creation were obtained in some cases of platinum group metals(44Ru by FBR,46 Pd by LWR) and rare earth(64Gd by LWR,66 Dy by FBR). Therefore, systems based on LWR and FBR have their own advantages depending on target elements. Furthermore, it was found that creation rates of even Z(= Z + 1) elements from odd Z ones were higher than the opposite cases. This creation rate of an element was interpreted in terms of "average 1-group neutron capture cross section of the corresponding target element σc Z defined in this work. General trends of the creation rate of an even(odd) Z element from the corresponding odd(even) Z one were found to be proportional to the 0.78th(0.63th) power of σc Z, however with noticeable dispersion. The difference in the powers in the above analysis was explained by the difference in the number of stable isotopes caused by the even-odd effect of Z.     

Study of Titanizing the Surface of Copper Substrates by the Double Glow Discharge Plasma Surface Alloying Technique

This paper discusses a study in which Ti surface alloying has been performed on copper substrates by means of a double glow discharge plasma surface alloying technique. The micro-structure, the phase structure, the micro-hardness and the distribution of Ti concentration of alloying layer were investigated in detail by XRD, SEM and so on. The effect of process parameters on the alloying layer was studied. The experimental results show that a Ti solid solution with the precipitation Cu4Ti alloying layer has been formed on the copper surface. The thickness of the alloying layer is about 120 μm and the surface titanium concentration gradually decreases from ω （Ti） = 87% to ω （Ti） = 4%. The micro-hardness of the alloying layer is between 300 HV-800 HV. Source sputtering, surface absorption, ion bombarding and high temperature diffusion are the major factors that affect the alloying layer.     

Frication Property of Mo-Cr-Infiltrated Steel Layer by Plasma Surface Metallurgy

Introduced in this article is the technique to acquire a high performance strengthened layer on carbon steel samples, namely, plasma alloying on the surface of Q235 steel and heat treatment technology. With this technique the alloying elements of Mo, Cr, and C can be obtained on the surface of Q235 steel samples. The content of the constituent elements is approximately up to high speed steels （HSS）. The surface property required for the HSS after hardening and low tempering is attained. In the test, the alloying elements Mo and Cr were penetrated into the Q235 steel samples by glow discharge sputtering so that the content of the alloyed layer on the surface of the Q235 steel samples was about 20% Mo and 10% Cr. Two kinds of experiments were conducted. One was to carry out ultra-saturated carburization. The alloyed layer＇s composition was similar to molybdenum HSS with surface carburizing of more than 2.0%. The carbides of the alloyed layer were compact, uniform and disperse without a coarse eutectic ledeburite structure, The another was ion nitriding after the alloying elements of Mo and Cr were penetrated. The first process included hardening with low tempering and hardening with cryogenic treatment for 2 hr and low tempering. The second one was ion nitriding only. It was found that the surface hardness after cryogenic treatment is up to 1600HV, much higher thanthat without cryogenic treatment. The abrasion test results indicate that, without the penetrated alloy elements Mo and Cr and without cryogenic treatment and ion nitriding, the friction coefficient is lower by one order of magnitude. The change in relative resistance is similar to the change in the friction coefficient, but without a proportional relationship,     

Extraction study of rare earth elements with N,N'-dibutyl–N,N'-di(1-methylheptyl)-diglycolamide from hydrochloric acid

A novel,unsymmetrical diglycolamide,N,N'-dibutyl-N,N'-di(1-methylheptyl)-diglycolamide(DBD1MHDGA),was synthesized.The extraction of rare earth elements(REEs) from a hydrochloric acid medium with DBD1 MHDGA was investigated.The results of the extraction experiments indicated that the distribution ratios of RE(Ⅲ) ions increase with an increase in HC1 concentration,atomic number,and extractant concentration.The calculated thermodynamic data show that the extraction process is an exothermic reaction.The organic phase loaded rare earth ions were characterized by infrared spectroscopy.The composition of the extracted complex was determined.