Man-made plutonium in environment — possible serious hazard for living species

It is pointed out that, contrary to the situation with natural Rn, the growing concentration of man-made Pu in environment — natural water soil plants and food — can provide the serious danger for all kind of animals and especially for mankind. Really, as it was established recently, element Pu is accumulated in human body during all the life and the dangerous concentration estimated to be 10⁻¹² – 10⁻¹³ grapm Pu per gram of human tissues. Unfortunately up to now there are no simple nonexpensive methods of Pu determination at the level of sensitivity 10⁻¹⁴ – 10¹⁵ g/g which can provide the determination of Pu even in 0.2 g of human tissue. We warn that now the average concentration of Pu in human body is not less than 10⁻¹⁴ g/g and much higher for some “hot” regions in Europe and Asia. We propose to discuss the problem of organizing world net exploration of Pu in environment — similarly to Rn exploration program — and personnel Pu monitoring for inhibitions of Pu damaged regions. Our approach to the problem is based on chemical separation of Pu, on determination of Plutonium by high fission cross section with thermal neutrons ²³⁹Pu(n,f) reaction and by control of possible admixture of ²³⁵U isotope by ²³⁸U(γ, f) reaction in Pu preparations. The problem of increasing of sensitivity of Pu analysis up to 10⁻¹⁴ – 10⁻¹⁵ g/g is discussed in detail.     

On the determination of subpicogram concentrations of Pu in environment and living species

The method of ²³⁹Pu minor content determination based on subsequent activation with thermal neutrons and gamma-rays was applied for preparations chemically separated from soils, water, river sediments and some living species. The obtained level of sensitivity for routine analysis is proved to be equal 10⁻¹³ gram Pu per gram of sample.     

Track detector study of fission of bismuth nuclei induced by He, radioactive He and Li ions

The cross-sections for fission of ²⁰⁹Bi induced by secondary beams of ⁶He by ⁴He and ⁷Li were measured. For the registration of fission fragments polyterephtalate plastic and muscovite mica detectors were used. In the case of the reaction of helium ions with bismuth the cross-section of the fission of ²⁰⁹Bi induced by ⁶He are significantly higher than the corresponding -particle-induced fission cross-section.     

Automation system for optical counting of nuclear tracks

An automation system consisting of the microscope, video camera and Pentium PC with frame recorder was created. The system provides counting of nuclear tracks on the SSNTD surface with a resolution of 752 × 582 points, determination of the surface area and main axis of the track. The pattern recognition program was developed for operation in Windows 3.1 (or higher) ensuring a convenient interface with the user. In a comparison of the results on automatic track counting with the more accurate hand mode it was shown that the program enables the tracks to be detected even on images with a rather high noise level. It ensures a high accuracy of track counting being comparable with the accuracy of manual counting for densities of tracks in the range of up to 2·10⁵ tracks/cm². The automatic system was applied in the experimental investigation of uranium and transuranium elements.     

On the Thermal Stability of Tracks in Plastics and some Uses in Radiography

The eradication of alpha and fission tracks and the selective track discrimination by heat treatment have been studied in cellulose nitrate, cellulose acetate, and polycarbonate sheets. Some applications of the phenomena in alphagraphy and fissionography are presented.     

Determination of isotopic composition of plutonium in hot particles of the Chernobyl area

The knowledge of the isotopic composition of man-made transuranium elements (TUE) in the environmental samples is of great interest because, on the basis of these data, statements about the origin of the TUE can be made. One of the most radiotoxic elements released during reactor accidents and nuclear weapons tests was plutonium with the alpha emitters ²³⁸Pu, ²³⁹Pu, ²⁴⁰Pu, ²⁴²Pu and the beta-emitter ²⁴¹Pu which decays into ²⁴¹Am. The determination of plutonium in “hot” particles from the Chernobyl reactor was accomplished by means of solid state nuclear track detectors registering the alpha particles and by alpha spectroscopy after chemical treatment. Furthermore, in order to perform a complete analysis of the isotopic composition one of the “hot” particles has been investigated by resonance ionization mass spectrometry which possesses an excellent sensitivity and a good isotopic resolution.     

Solid state species under the influence of nature and science

From September 15^th – 22^nd, 1996 the 3^rd Euroconference on Solid State Ionics took place in the Hotel “Baia delle Ginestre„ near Teulada, which is situated on the marvellous island of Sardinia. About 100 participants came from countries like Russia, the Czech Republic, Poland, Bulgaria, Japan, China, Scotland, England, France, Belgium, Portugal, Greece, Italy, Spain, Israel and Germany and had to deal with almost all fields of Solid State Ionics. The conference and its atmosphere, which was very nice indeed, will be described in detail using some models for the processes which were taking place. Some conclusions will be drawn as well.     

Determination of spatial and energy distributions of neutrons in experiments on transmutation of radioactive waste using relativistic protons

The experiments on transmutation of ¹²⁹I and ²³⁷Np using uranium-lead targets surrounded by a paraffin moderator were performed at the Joint Institute for Nuclear Research (JINR, Russia). The targets were irradiated by 1.5 GeV and 7.4 GeV protons at the Synchrophasotron of JINR. In the frame of present work spatial and energy distributions of neutrons on the surface of the paraffin moderator were measured using SSNTD technique. It is shown that measured values of spetral indices do not pretend on the energy of incident protons but depend on the target composition. The presence of the uranium insertion softens neutron spectra.     

Fissile radionuclides in thyroid of the inhabitants of the gomel region in belarus and peculiarities of their distribution

Severe radiation damages with the following substitution of connective tissue are the effect of high doses in microvolumes of the thyroid. Calcium, strontium and uranium deposited into these sections was more as compared to a normal tissue of the thyroid. An estimation of the microdistribution of fissile radionuclides was carried out using the method of fragmental radiography. The analysis of tracks done visually using a microscope magnification of 300 revealed the local density of fission fragments up to 10³ mm⁻². The irradiation of the surrounded cells which contain the hidden genetic damages, initiated by radioiodine, does not exclude their possible promoter role in thyroid cancerogenesis.     

On the formation of amorphous layers by interdiffusion in zirconium-copper system

Formation of amorphous phase by solid state reaction has been observed in bulk copper-zirconium couples. Transmission electron microscopy (TEM), Auger electron spectroscopy (AES) and differential scanning calorimetry (DSC) techniques have been employed to detect and study the amorphous phase. The experimental observations have been explained with a model, which considers the breakdown of the a-zirconium lattice due to the solute enrichment beyond a certain limit where the nucleation of the amorphous phase becomes thermodynamically possible. The present-experiments convincingly show that amorphous phase can form in bulk diffusion couples made from large-grained well-annealed material and conclusively establish that the presence of crystal defects in high concentrations is not a pre-requisite for the formation of amorphous phase.     

Temperature Effects in the Raman Spectrum of Solid Orthocarborane

Abstract

Variable temperature studies of the laser Raman spectrum of solid orthocarborane indicate a change in the line widths of the peaks in the observed frequency region from 745 cm^?1 to 815 cm^?1. A marked change in the line width of the 807 cm^?1 peak around 4°C confirms recently observed anomalies in the NMR spectrum at this temperature.     

Surface‐enhanced Raman spectroscopy of genomic DNA from in vitro grown plant species

Surface‐enhanced Raman scattering (SERS) effect was used to demonstrate ultrasensitive optical detection of nucleic acids. In this work, the SERS spectra of seven genomic DNAs from leaves of Arnica montana (L.), Fam. Compositae, Astragalus peterfii (Jáv.), Fam. Fabaceae, Kalanchoe x hybrida, Fam. Crassulaceae, strawberry (Fragaria x ananassa Duch.), Fam. Rosaceae, carnation (Dianthus caryophyllus L.), Fam. Caryophyllaceae, apple (Malus domestica Borkh.), Fam. Rosaceae and Persian violet (Exacum affine Balf.), Fam. Gentianaceae were analyzed in the wavenumber range 200–1800 cm⁻¹. SERS signatures, spectroscopic band assignments and structural interpretations of these plant genomic DNAs are reported. SERS spectra of nucleic acids are compared here with caution, because these signals are time‐dependent. The SERS spectra corresponding to DNA from Arnica, Dianthus, Fragaria and Kalanchoe leaves show well‐resolved, accurate bands, providing thus a high molecular structural information content. Based on this work, specific plant DNA–ligand interactions or DNA structural changes induced by plant stress conditions associated with their natural environment might be further investigated using SERS spectroscopy. Besides, this study will generate information that is valuable in the development of label‐free DNA‐based nanosensors for chemical probing in the living cell. Copyright © 2011 John Wiley & Sons, Ltd.     

Application of the escape factor method for determination of excited states densities in a low‐pressure argon radio‐frequency discharge

Reabsorption of the emitted light in the plasma volume has recently been used for density measurements of the lower level of optical transition by interpretation of emission spectra employing the escape factor concept. Following this idea, we apply this method to a radio‐frequency argon discharge. By revising the theoretical background, the impact of different assumptions on excited species spatial distributions is investigated. Comparing with 1s₅ and 1s₄ concentrations obtained with laser absorption spectroscopy, the range of applicability of those assumptions is analyzed at different discharge parameters. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

On the problem of the relation between phason elasticity and phason dynamics in quasicrystals

It has recently been claimed that the dynamics of long-wavelength phason fluctuations has been observed in i-AlPdMn quasicrystals [S. Francoual et al. Phys. Rev. Lett. 91, 225501 (2003); A. Létoublon et al. 54, 753 (2001)]. We will show that the data reported call for a more detailed development of the elasticity theory of Jarić and Nelsson [M.V. Jarić and D.R. Nelsson, Phys. Rev. B 37, 4458 (1988)] in order to determine the nature of small phonon-like atomic displacements with a symmetry that follows the phason elastic constants. We also show that a simple model with a single diffusing tile is sufficient to produce a signal that (1) is situated at a “satellite position” at a distance q from each Bragg peak; that (2) has an intensity that scales with the intensity of the corresponding Bragg peak; (3) falls off as 1/q²; and (4) has a time decay constant that is proportional to 1/Dq². It is thus superfluous to call for a picture of “phason waves” in order to explain such data, especially as such “waves” violate many physical principles.     

金刚石压砧内单轴应力场对物质状态方程测量的影响

金刚石压砧的几何结构使得在高压下封垫内的样品通常处于单轴应力场中：压砧轴向加载应力最大,径向应力最小.由于金刚石压砧内非静水压单轴应力场的影响,用传统的高压原位X射线衍射方法测得的物质压缩曲线一般位于理想静水压压缩曲线之上.利用金刚石压砧径向X射线衍射技术以及晶格应变理论,结合最近的钨、金刚石和硼六氧样品的高压原位同步辐射径向X射线衍射实验结果,从宏观差应力、样品强度、标压物质和待测物质强度的关系三个方面分析讨论了金刚石压砧内单轴应力场对物质状态方程测量的影响及解决方案. 关键词： 金刚石压砧 单轴应力场 高压原位X射线衍射 状态方程     

On line shape of electromagnetically induced transparency in a multilevel system

We present a detail analysis of the line shape of electromagnetically induced transparency (EIT) in a Doppler broadened five level atomic system based on density matrix formalism. It has been shown that the velocity averaged EIT line shape in a multilevel system is very sharp. The effect of the ground state decay rates on the EIT peak has also been investigated. The linear and non-linear variations of the EIT line width (FWHM) for different pump and probe power ratios are shown. Considering the D₂ transition of ⁸⁵Rb atom the dependence of EIT width and height on pump power has been experimentally measured. Simulated spectra are compared with the experimentally obtained one. The effect of buffer gas on the EIT peak has also been observed experimentally as well as theoretically.     

On the absence of intermediate phases in the two-dimensional Coulomb gas

For a simple, continuum two-dimensional Coulomb gas (with soft cutoff), Gallavotti and Nicoló [J. Stat. Phys. 38:133–156 (1985)] have proved the existence of finite coefficients in the Mayer activity expansion up to order 2n below a series of temperature thresholdsT _n =T [1+(2n–1)^–1] (n=1, 2,...). With this in mind they conjectured that an infinite sequence of intermediate, multipole phases appears between the exponentially screened plasma phase aboveT ₁ and the full, unscreened Kosterilitz-Thouless phase belowT T _KT. We demonstrate that Debye-Hückel-Bjerrum theory, as recently investigated ford=2 dimensions, provides a natural and quite probably correct explanation of the pattern of finite Mayer coefficients while indicating the totalabsence of any intermediate phases at nonzero density ; only the KT phase extends to >0.     

在氧-水蒸气存在下单相Sr2(Gd,Ce)2Cu2RuO10的合成及其电学性质

传统固相反应所合成的锶系钌铜氧化物，通常总伴有少量铁磁性SrRuO₃杂相.采 用氧(或空 气)_水蒸气混合气氛下的新型固相反应，既能成功合成锶系钌铜氧化物的前驱物纯相Sr₂G dRuO₆(211相), 也能进一步在相对低的温度下成功合成锶系钌铜氧1222纯相化 合物RuSr₂(Gd,Ce)₂Cu₂O₁₀ (Ru_1222）， 使其中SrRuO _{关键词： 水蒸气参与的新型固相反应 2}(Gd')" href="#">RuSr₂(Gd 2Cu_{2< /sub>O10纯相')" href="#">Ce)2Cu2< /sub>O10纯相 3杂相')" href="#">SrRuO3杂相 电学性质}