ICP—AES techniques applied to analysis of precious metals in ores

A method for the simultaneous determination of precious metals and matrix elements in Fe and Cu ores is studied.The instrument used is ICAP-9000 polychromator and its accessory monochromator(N 1),Interferences of matrix are eliminated by matrix matching method,i.e.the influence of matrix was corrected by minus equivalent concentration method,The experiments show that the method is simple,sensitive and reliable;especially,suitable for determination of Au in Cu-Au ores.     

XPS characterization of different thermal treatments in the ITO–Si interface of a carbonate-textured monocrystalline silicon solar cell

In this work we have applied the X-ray photoelectron spectroscopy (XPS) in depth to study, for the first time, the influence of different thermal treatments in the ITO–Si interface of a monocrystalline Si-based solar cell where the Si surface is carbonate-textured and covered by an ITO sputtered layer. The efficiency of the solar cells significantly increases when thermal treatments are applied just after the ITO deposition. The efficiency is also dependent on the characteristics of the pyramidal relief of the silicon surface previously obtained by immersion of the Si wafers in a sodium carbonate/bicarbonate solution. An efficiency of 15.5% has been obtained with an optimized texturization of the silicon substrates and an annealing treatment of the solar cells at 400 °C just after the ITO deposition.     

GISAXS and GIWAXS analysis of amorphous–nanocrystalline silicon thin films

Amorphous–nanocrystalline silicon thin films were deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) on glass substrate with various silicon nano-crystal size distributions and volume fractions. The samples were examined by Grazing Incidence Small Angle X-ray Scattering (GISAXS) and Grazing Incidence Wide Angle X-ray Scattering (GIWAXS) at the Austrian SAXS beamline (Synchrotron Elettra, Trieste) using an X-ray beam energy of 8 keV. The grazing incidence angle varied from the critical angle to 0.2° above the critical angle. This allowed the examination of the samples at different depths, and the distinction of the surface scattering contribution from the particles scattering in the bulk. The sizes of the “particles” obtained from the horizontal and vertical sections of 2D GISAXS patterns were between 2 nm and 6 nm. Since GISAXS is sensitive to electron density differences (contrast) between the scattering bodies and the surrounding matrix, it is not evident whether the particles are nano-crystals or just voids embedded in amorphous matrix. However, the size of the crystals calculated from the line-shape analysis of peaks in GIWAXS spectra and the crystal size distribution obtained from High-Resolution Transmission Electron Microscopy (HRTEM) images agree well with the size of “particles” estimated from GISAXS, strongly indicating that the observed particles are silicon nano-crystals.     

Quantitative analysis of 3D vasculature for evaluation of angiogenesis in liver fibrosis with SR-μCT

The micro-CT imaging of vasculature is a powerful tool for evaluation of angiogenesis,a prominent characteristic of hepatic fibrosis.The segment or bifurcation density,which is usually adopted to evaluate the degree of hepatic fibrosis,does not always work and may lead to incorrect assessment,especially when the threedimensional vasculature obtained is imperfect in sample preparation or image collection.In this paper,we propose a new parameter to solve this problem.The experimental results demonstrate that the method is robust and reliable,and is practical for angiogenesis evaluation,despite of image data imperfections.This quantitative analysis method can be extended to investigate other kinds of diseases in which vasculature change is a key indicator.     

Structural features of martensite α-phases in alloys of uranium with transition metals

The structures and formation kinetics are considered for martensite α phases in diffusionless transformation of the γ and β phases of alloys between uranium and transition metals. The general features of the {ie118-1} martensite phase and of the martensite in a steel have been determined by metallography, x-ray structure analysis, and dilatometry, and the same has been done for the martensite {ie118-2} and {ie118-3} phases and martensite in indium-thallium and gold-cadmium alloys. Kinetic features are given for the two-stage diffusionless {ie118-4} transformation in uranium-molybdenum and uranium-niobium alloys, in which the second stage {ie118-5} has the characteristics of a thermoelastic martensite transformation that is realized not only as the temperature varies but also in response to external stress. Bochvar All-Russia New Materials Research Institute, Russian Federation State Scientific Center. Translated from Atomnaya énergiya, Vol. 86, No. 2, pp. 113–120, February, 1999.     

Distributions of boron and phosphorus implanted in silicon in the energy range 0.1–1.5 MeV

Boron and phosphorus were implanted in p-type and n-type silicon wafers in the energy range from 0.1 to 1.5 MeV. Three different methods were used to determine the distribution of the ions: SIMS, CV and NRA. The results were fitted to a Pearson IV distribution in order to extract moments for describing the distributions analytically. The projected ranges agree well with the theoretical values. Deviations are observed at higher energies. Projected range standard deviations are significantly greater than the tabulated values. The skewness clearly deviates from available tabulated data, although the same trend is observed.     

Behavior of Paramecium sp. in solutions containing Sr and Pb: Do Paramecium sp. alter chemical forms of those metals?

The behavior of Paramecium sp. (Paramecium bursaria) in aqueous solutions containing Sr and Pb was investigated to determine the role of protozoa in the migration of radionuclides in the environment. Precultured living cells of P. bursaria were exposed to aqueous solutions containing 0.01 or 0.05 mM Sr or Pb at pH 7 for 24 h. For comparison, pre-killed cells were treated with the metal solutions in the same way. Two-dimensional elemental mappings of cells were obtained by micro-PIXE. Aquatic species of Sr and Pb were analyzed by size exclusion chromatography (SEC) coupled online to ultraviolet (UV) spectroscopy and inductivity coupled plasma mass spectroscopy (ICP-MS). The amounts of Sr adsorbed or taken up by the cells surviving for 24 h and adsorbed on pre-killed cells were below the detection limit. Cells of P. bursaria adsorbed or took up a fraction of Pb. The Pb adsorbed or taken up by the cells surviving for 24 h in the Pb solution was barely detectable, while the Pb adsorbed on pre-killed cells was clearly mappable. These findings suggest that living cells of P. bursaria have functions that reduce adsorption or uptake of Pb on the cells. Quantitative and SEC-UV-ICP-MS analyses of the Sr and Pb in aqueous phases showed no clear evidences that living cells of P. bursaria alter the chemical form of Sr or Pb remaining in the aqueous phases after the cell-solution contact.     

Fabrication of Si–C–N compounds in silicon carbide by ion implantation

The chemical variation and depth profile of silicon carbide implanted with nitrogen and overgrown with epitaxial layer has been studied using X-ray photoelectron spectroscopy (XPS). The results of this study have been supplemented by transmission electron microscopy (TEM) imaging and electron energy loss-spectroscopy (EELS) in an attempt to correlate the chemical and structural information. Our results indicate that the nitrogen implantation into silicon carbide results in the formation of the Si–C–N layer. XPS revealed significant change in the bonding structure and chemical states in the implanted region. XPS results can be interpreted in terms of the silicon nitride and silicon carbonitride nanocrystals formation in the implanted region which is supported by the electron microscopy and spectroscopy results.     

Operational analysis of nuclear research facilities in 1999–2008

The actual data on the number, type, operating state, and use of nuclear research facilities are presented. The generalized operational indices of the facilities for 1999–2008 are given; they were obtained on the basis of an analysis of the information entering the sector center for the collection and analysis of safety information concerning nuclear research facilities. Information is presented on the research being conducted at the facilities and the intensity with which the research reactors are used. Attention is focused mainly on the safety of nuclear research facilities. The results of an analysis of disruptions of the operation of the facilities are examined in detail. It is shown that the operation of nuclear research facilities is safe from the nuclear and radiological standpoints.     

Non-dimensional analysis of static bifurcation in a natural circulation loop

The steady-state characteristics of a two-phase natural circulation loop were investigated based on the homogenous model. Transcendental equations of non-dimensional loop mass flow rate under various conditions were also derived. The static bifurcation diagram of a two-phase natural circulation described with non-dimensional variables Npch-m^＋ was obtained. In addition, various steady-state characteristics of a natural circulation loop were analyzed and discussed. These characteristics include the existence of multiple solutions under certain conditions, and the maximum mass flow rate. The authors also examined the effects of important parameters such as sub-cooling number, riser-to-heated-region length ratio, and riser-to-heated-region diameter ratio.     

Cs–Te corrosion depth dependence on distribution of chromium carbide precipitation in high chromium steel

In an attempt to investigate Cs–Te corrosion depth dependence on distribution of chromium carbide precipitation in high chromium steel, Cs–Te corrosion out-pile tests of two 9Cr steels with different distributions of chromium carbide were carried out at 975 K for 100 h, and their corrosion depths were compared. The corrosion is obviously more advanced in a specimen which has grain boundary carbide than in the one that does not. A considerable reason of the result is that the carbide distributed at grain boundaries promoted the corrosion reaction and the corrosion extended along the grain boundary. This is the first case in which the Cs–Te corrosion depth dependence on distribution of chromium carbide precipitation in Fe–Cr steel is clarified experimentally.     

Range distributions of 50–400 keV Hg+in amorphous silicon and Si-Ar binary targets

Range distributions of 50–400 keV Hg⁺ in amorphous Si and Si-Ar binary targets have been investigated by Rutherford backscattering spectrometry. The Si(100) wafers were amorphized by means of 150 keV Ar⁺ irradiation to a dose of 2 × 10¹⁵ ions/cm². To produce Si-Ar binary targets, the Si(100) wafers were implanted with 150 keV Ar⁺ to a dose of 3 × 10¹⁷ ions/cm². 50–400 keV Hg⁺ were introduced into amorphous Si and Si-Ar binary targets in increments of 50 keV. Parallel scanning of the Hg⁺ beams was used. The measured ranges and range stragglings have been compared to the Biersack theory. The results show that good agreements are found between the experimental and theoretical projected ranges for both Si and Si-Ar, but the predicted range straggling for both Si and Si-Ar are systematically lower than the experimental results in the case of a first order treatment. After correcting for second order energy loss terms, a better agreement for the range straggling is obtained.     

Fluorine analysis of human dentin surrounding resin composite after fluoride application by μ-PIGE/PIXE analysis

The use of fluoride for the prevention of caries is based on the transformation of hydroxylapatite to fluoroapatite in the presence of fluoride ions, thereby strengthening tooth structure. Adhesion of dentin and resin composite (tooth-colored restoration material) requires a dentin bonding system, since resin composite is not able to adhere to dentin directly. Demineralization of dentin by acid etching is an important step in the dentin bonding system, however, demineralization also introduces weaknesses in tooth structure. If the demineralized dentin could be strengthened by the application of fluoride, then the dentin-resin composite bond strength might also improve. To test this hypothesis, the present study evaluated the influence of fluoride applications on the strength of the dentin-resin composite bond by (1) tensile strength testing analyses, (2) SEM analyses of tooth structure, and (3) detection of calcium (Ca) and fluorine (F) distribution patterns by micro proton-induced X-ray emission (μ-PIXE) and micro proton-induced gamma-ray emission (μ-PIGE) analyses conducted at the Takasaki Ion Accelerators for Advanced Radiation Application (TIARA) at the Takasaki Advanced Radiation Research Institute (TARRI).In this study, the dentin in extracted human molars was exposed by grinding and the dentin was etched with 35% phosphoric acid. Fluoride was applied at two concentrations, 0.022% (100 ppm F) and 2.21% (10,000 ppm F) NaF solution, for two time periods, 30 and 60 s, prior to bonding the resin composite with the treated dentin. Controls were prepared in the same manner, but without the fluoride application. Bond strength was measured with a micro-tensile testing unit, and the fluorine and calcium distributions at the interface between dentin and resin composite were detected by μ-PIGE and μ-PIXE analysis, respectively.Results indicate that the 10,000 ppm F applications resulted in higher bond strengths than observed in either the 100 ppm F applications or the control group. In addition, PIGE analyses showed high concentrations of fluorine in the hybrid bonding layer of the 10,000 ppm F samples, suggesting that the fluorine contributes to the strength of the dentin-resin composite bond. Detection of fluoroapatite within the hybrid bonding layer suggests that bond strength involves remineralization processes.     

Identification tables for use in the analysis of α and β activities

In order to facilitate the identification of activities being subjected to analysis, tables are compiled according to data published prior to 1958 containing the distribution of all known - and -radioactive isotopes as a function of their T_1/2, end-point energies of their -spectra, and -particle energies. The tables make it possible to establish a group of isotopes with a previously established T_1/2 and energies of radioactive emission. In a number of cases, the use of a scheme involving the radioactive decay chain may also prove expedient in the identification of activities.We consider it our duty to express our gratitude to Yu. A. Zysin for a discussion and his advice.     

Progress of neutron induced prompt gamma analysis technique in 1988～2003

This paper describes new development of the neutron induced prompt gamma-ray analysis (NIPGA) technology in 1988～2003. The pulse fast-thermal neutron activation analysis method, which utilized the inelastic re action and capture reaction jointly, was employed to measure the elemental contents more efficiently. Lifetime of the neutron generator was more than 10000h and the performance of detector and MCA reached a high level. At the same time, Monte Carlo library least-square method was used to solve the nonlinearity problem in the NIPGA.     

Micro－PIXE analysis of trace element composition and their distribution in minerals of mantle peridotite

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Micro—PIXE analysis of trace element composition and their distribution in minerals of mantle peridotite

The proton microprobe and the quantitative micro-PIXE analysis technique are used to determine trace element composition and distribution in minerals of mantle peridotite,therefore,additional useful information is provided on the study of upper mantle mineral phase transformation.An example reported here is the study on the geochemical behavior of trace elements in minerals of Suoluoshu mantle peridotite from Shandong province,which was in the process of mineral phase transformation from spinel to garnet.The study shows that trace element composition and distribution display obvious change in minerals while the mineral phase is transformed from spinel to garnet.Most of the trace elements analyzed reside in clinopyroxene and spinel.However,garnet is nearly poor in all of these elements.This phenomenon is associated with the infiltration of soultion and the existence of micropgrained inclusions in minerals in the process of mantle metasomatism.     

Measurement and analysis of species distribution in laser-induced ablation plasma of an aluminum–magnesium alloy

We proposed a theoretical spatio-temporal imaging method, which was based on the thermal model of laser ablation and the two-dimensional axisymmetric multi-species hydrodynamics model. By using the intensity formula, the integral intensity of spectral lines could be calculated and the corresponding images of intensity distribution could be drawn. Through further image processing such as normalization, determination of minimum intensity, combination and color filtering, a relatively clear species distribution image in the plasma could be obtained. Using the above method, we simulated the plasma ablated from Al–Mg alloy by different laser energies under 1 atm argon, and obtained the theoretical spatio-temporal distributions of Mg I, Mg II, Al I, Al II and Ar I species, which are almost consistent with the experimental results by differential imaging. Compared with the experimental decay time constants, the consistency is higher at low laser energy, indicating that our theoretical model is more suitable for the plasma dominated by laser-supported combustion wave.     

Preliminary analysis of tritium fuel cycle in Z-pinch-driven fusion–fission hybrid reactor

Attaining tritium self-sufficiency is indispensable in a Z-pinch-driven fusion–fission hybrid reactor(ZFFR).In this paper,a conceptual design is presented in which the Z-FFR tritium cycle system was divided into eight subsystems.A theoretical analysis of tritium inventory based on the mean residence time was performed to quantitatively obtain the tritium distribution in each subsystem.Tritium self-sufficiency judgment criteria were established using a tritium mass flow analysis method.The dependency relationships between the burning rate,tritium breeding ratio,extraction efficiency,and tritium self-sufficiency were also specified for the steady state.