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31.
Phase relations and phase stabilities have been derived for the ternary systems RE─B─N (RE = Nd, Sm, or Gd) at elevated temperatures (1400°C and above) by means of X-ray powder analysis. Under the experimental conditions selected, various ternary compounds are found to be stable: Nd3 B2 N4 with the Ce3 B2 N4 type and (Nd,Sm,Gd)BN2 with the PrBN2 type. Phase equilibria at 1400°C and under 105 Pa of argon are mainly characterized by the incompatibility of the RE metals Nd, Sm, and Gd with BN due to the competing equilibria between the RE tetraborides and the RE mononitrides. Each of the ternary compounds, however, is found to be in a two-phase equilibrium with hex -BN. Because of the different thermodynamic stabilities within the various structure series of ternary rare-earth boron nitrides RE3 B2 N4 and REBN2 , the compound Nd3 B2 N4 is observed only at temperatures below 1800°C and under 105 Pa of Ar, whereas GdBN2 is found to be stable only at temperatures above 1400°C under a partial pressure of 105 Pa of N2 . 相似文献
32.
Mario Villa Markus Haydn Georg Steinhauser Helmuth Böck 《Nuclear Engineering and Design》2010,240(12):4091-4095
The safety report of the TRIGA Mark II reactor in Vienna includes three accident scenarios and their deterministic dose consequences to the environment. The destruction of the cladding of the most activated fuel element, the destruction of all fuel elements and a plane crash were considered scenarios in that report. The calculations were made in 1978 with the software program named STRISK. In this paper, the program package PC Cosyma was applied on the TRIGA Mark II reactor in Vienna and the deterministic consequences of the scenarios to the environment were updated. The fission product inventories of all fuel elements were calculated with ORIGEN2. To get meteorological data of the atmospheric condition around the release area, a weather station was installed. The release parameters were taken from the safety report or were replaced by worst case parameters. This paper focuses on two accident scenarios: the destruction of the cladding of the fuel element with the highest activity content and the case of a large plane crash. The current accident scenarios show good agreement with the calculations from 1978, hence no technical modifications in the safety report of the TRIGA reactor Vienna were necessary. Even in the very worst case scenario – complete destruction of all fuel elements in a large plane crash – the expected doses in the Atominstitut's neighborhood remain moderate. 相似文献
33.
This review covers the area of bioapplications of layer‐by‐layer assembled polymer planar films and microcapsules—biologically relevant responses stimulated by light. We present recent progress in light‐stimulated release of bioactive molecules from the assembled structures. Functionalization of the films with metal nanoparticles and bioactive molecules that provide the films with light sensitivity and reservoir properties is also described. The use of these films in the delivery of bioactive molecules is closely related to light‐induced cargo release from capsules; this promising method of intracellular delivery is also addressed. Copyright © 2012 Society of Chemical Industry 相似文献
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Large‐Scale Noniridescent Structural Color Printing Enabled by Infiltration‐Driven Nonequilibrium Colloidal Assembly
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Ling Bai Van Cuong Mai Yun Lim Shuai Hou Helmuth Möhwald Hongwei Duan 《Advanced materials (Deerfield Beach, Fla.)》2018,30(9)
Structural colors originating from interaction of light with intricately arranged micro‐/nanostructures have stimulated considerable interest because of their inherent photostability and energy efficiency. In particular, noniridescent structural color with wide viewing angle has been receiving increasing attention recently. However, no method is yet available for rapid and large‐scale fabrication of full‐spectrum structural color patterns with wide viewing angles. Here, infiltration‐driven nonequilibrium assembly of colloidal particles on liquid‐permeable and particle‐excluding substrates is demonstrated to direct the particles to form amorphous colloidal arrays (ACAs) within milliseconds. The infiltration‐assisted (IFAST) colloidal assembly opens new possibilities for rapid manufacture of noniridescent structural colors of ACAs and straightforward structural color mixing. Full‐spectrum noniridescent structural colors are successfully produced by mixing primary structural colors of red, blue, and yellow using a commercial office inkjet printer. Rapid fabrication of large‐scale structural color patterns with sophisticated color combination/layout by IFAST printing is realized. The IFAST technology is versatile for developing structural color patterns with wide viewing angles, as colloidal particles, inks, and substrates are flexibly designable for diverse applications. 相似文献
37.
Vareková RS Bradác I Plchút M Skrdla M Wacenovsky M Mahr H Mayer G Tanner H Brugger H Withalm J Lederer P Huber H Gierlinger G Graf R Tafer H Hofacker I Schuster P Polcík M 《Computer methods and programs in biomedicine》2008,90(1):89-94
RNA interference (RNAi) has become an important tool to study and utilize gene silencing by introducing short interfering RNA (siRNA). In order to predict the most efficient siRNAs, a new software tool, RNA Workbench (RNAWB), has been designed and is freely available (after registration) on http://www.rnaworkbench.com. In addition to the standard selection rules, RNAWB includes the possibility of statistical analyses of the applied selection rules (criteria). The role of RNA secondary structures in the RNA interference process as well as the application of sequence rules are discussed to show the applicability of the software. 相似文献
38.
Nunes IA Helmuth R Schroeter A Mead GC Santos MA Solari CA Silva OR Ferreira AJ 《Journal of food protection》2003,66(2):324-327
The occurrence of Salmonella Enteritidis (SE) phage types (PTs) in samples collected from healthy and diseased chickens, in outbreaks of human gastroenteritis related to the consumption of egg products, in samples of poultry meat, in pipped embryos of broiler chickens, in meat meal, in poultry-rearing environments, and in many foods (cheese, mayonnaise, cake, and bacon) is described for strains isolated from 1995 to 1997 in Brazil. SE strains were isolated, and the most common PT was found to be PT 4, followed by PTs 7, 21, 35, 6, 4a, 8, 30, 6a, 5a, 1, and 1b. Fourteen strains were classified as react-but-do-not-conform strains, and one strain was not typeable. The results of this study demonstrate that PT 4 has a wider distribution among the sources studied than do any other SE phage types and is the most important phage type in human salmonellosis. 相似文献
39.
The properties of highly oriented pyrolytic graphite (HOPG) as a substrate for external reflection infrared spectroscopy in the mid-infrared region were investigated. Clean HOPG substrates, physisorbed hydrocarbon multilayers, and chemisorbed monolayers of p-substituted aryl radicals on HOPG were used as samples, and the experimental spectra were compared and complemented with the results of spectral simulations. From reflectivity measurements of clean HOPG surfaces with polarized light as a function of the light incidence angle and the frequency, the anisotropic optical constants n (refractive index) and k (absorption index) were determined for in-plane and out-of-plane directions with respect to the graphite basal plane. These constants express the semimetallic properties of HOPG, indicated by an intermediate reflectivity between a typical metal and a dielectric substrate and by asymmetric, distorted peak shapes in adsorbate film spectra, which represent a transition state between symmetrical, positive absorptions on metals and inverted, negative peaks on dielectric substrates. Regarding spectral sensitivity and surface selection rules, HOPG behaves much like a metal and is therefore an equally suitable substrate for external reflection infrared (IR) measurements. 相似文献
40.
Quondam lunar eclipse photometry data offered valuable information on the optical properties of the middle atmosphere, including dust particles. However, in comparison with nonspherical grains, the simple model of spherical particles has a different effect on solar radiation penetrating horizontally through the atmosphere. It is shown that the systems, in which the smallest size fraction of dust particles dominates, reduce irradiation of the Earth's shadow more efficiently if the grains are of irregular shape. In contrast, the populations contaminated by a certain amount of large particles cause an opposite effect. Depending on the actual form of the size distribution function of the irregular grains, the irradiance within the center of the Earth's shadow may change by 2 orders of magnitude in the visible spectrum. It is therefore evident that dust properties retrieved in the past are eligible candidates for reevaluation to correct a view on the dust trend in the middle atmosphere. Sample calculations are presented for the lunar eclipse observed on 19 January 1954. 相似文献