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111.
K. Wetzel 《Isotopes in environmental and health studies》2013,49(3):125-126
In einem dynamischen System vollziehen sich kontinuierlich ablaufende Stoffwandlungen, deren Ausgangsstoffe dem System ständig zufließen und deren Folgeprodukte das System kontinuierlich verlassen. Es wird das Verhalten eines solchen Systems mit drei Pools bei Markierungsexperimenten untersucht. Die Ergebnisse dieser mathematischen Untersuchungen werden auf die Erforschung des Stickstoffstoffwechsels laktierender Rinder mit Hilfe des stabilen Isotops 15N angewandt. In diesem Fall enthält das dynamische System zwei kleine stoffwechselaktive Pools und einen großen, niclit intensiv am Stoffwechsel beteiligten Körpereiweiβ-Pool. 相似文献
112.
K. Wetzel J. Dermietzel F. Bauer W. Jockisch M. Rösseler Ch. Wienhold 《Isotopes in environmental and health studies》2013,49(2):50-54
Tracermethoden können wichtige Beiträge zur Aufklärung katalytischer Kohlenwasserstoffreaktionen liefern. In dieser Arbeit werden einige Ergebnisse mehrjähriger Untersuchungen mit 14C-markierten Verbindungen zusammenfassend dargestellt. Es wird speziell auf Benzenbildungsreaktionen bei der Leichtbenzin-Reformierung und auf Reaktionsmechanismen bei der Isomerísierung von C8-Aromaten eingegangen. 相似文献
113.
R. Vetter 《Isotopes in environmental and health studies》2013,49(11):380-383
Die Bestimmung dünner Auftragsschichten auf bewegten Trāgermaterialien mit der β-Rūckstreumethode hängt wesentlich von der Empfindlichkeit der Messung und der Dynamik des Prozesses ab. In diesem Beitrag wird für spezielle Stoffe der Einfluβ der Trāgermaterialien bei Mehrschichtproblemen auf die Empfindlichkeit untersucht. 相似文献
114.
В. П. Бочսռ 《Isotopes in environmental and health studies》2013,49(8):317-321
A non-contact measuring method on electrostatic potential by using α-ray ionization is proposed. In this method potential of a charged material is estimated from ionic current flowing through an ion collector attached with a small 241Am source. As hade electrode surrounding the collector has a function of adjusting sensitivity and potential up to 50 kV was measured with precision of 1 kV. 相似文献
115.
116.
A solid state-based method using a hot reaction chamber is applied to the synthesis of Y2O3:Eu particles containing Eu from 0 to 5 mol%. The produced powders are studied using X-ray diffraction (XRD), scanning electron microscopy and transmission electron microscopy (TEM), as well as photoluminescence (PL) and radioluminescence tests. TEM and XRD results revealed the powder to be mono-disperse and in the form of a solid solution. The PL of Y2O3:Eu powder depends on both the concentration quenching effect (due to an excess of Eu concentration) and the surface luminescence effect (depicted by a higher surface area induced by the large phosphor concentration in the solution or smaller particle sizes). A 22Na gamma source is used to compare the recorded count rates for four Y2O3:Eu scintillator materials with different concentrations of Eu. Each scintillator composition is examined in four forms: solid pellets with a high volume porosity and three aqueous solutions of Y2O3:Eu particles of the different scintillator materials at concentrations of 25, 50 and 100 mg/mL. The radioluminescence results indicated that increasing the transparency and/or the amount of Eu mol% of the scintillators increases the net average counts. 相似文献
117.
B.P.C. Rao† S. Ramaswamy† C. Gopalakrishnan N. Satya Vijayakumar K.R. Ganesh 《哲学杂志》2013,93(25):3463-3473
Two-dimensional carbon nanosheets have been fabricated using inductively coupled radio frequency plasma-enhanced chemical vapour deposition. The structural properties of the nanosheets have been characterised using atomic force microscopy, scanning electron microscopy and X-ray diffractometer. The magnetisation of the samples was studied using vibrating sample magnetometer. The magnetisation of the nanosheets was found to be diamagnetic for fast synthesis processes (30 and 60 min). On the other hand, the nanosheets exhibited a weak ferromagnetic response for the slow (120 min) synthesis process. Energy dispersive spectrometry and atomic absorption spectroscopy confirmed that the magnetisation exhibited by the carbon nanosheets was an intrinsic property and that it was not due to contamination from the substrate. Raman spectroscopy studies revealed that the ferromagnetic carbon nanosheets have a higher ratio (1.20) of graphite peak (I G) to disordered peak (I D) than normally expected (0.75–0.90). Available data indicated that the magnetisation was due to the presence of structural disorders. 相似文献
118.
In the majority of cases, the effects of ion implantation are confined close to the implant zone but, potentially, the resultant distortions and chemical modifications could catalyse relaxations extending into the bulk substrate. Such possibilities are rarely considered but the present data suggest that high dose ion implantation of ZnO has induced bulk changes. Surface implants with Cu and Tb strongly modified the low temperature bulk thermoluminescence properties generated by X-ray irradiation. Suggestions are proposed for the possible mechanisms for bulk relaxations and structural characteristics, which may indicate where such instability may occur in other lattice structures. 相似文献
119.
Abstract The elastica is referred to the shape of the curve into which the centreline of a flexible lamina is bent. Hence, single-walled carbon nanotubes (SWCNTs) are treated as the elastica obtained from bending of graphene. The corresponding large deformation accompanies both the material and geometrical non-linearities. The morphology of the free-standing SWCNTs such as the natural angle of twist, bond lengths, tube radius and wall thickness are determined. Moreover, it is shown that the induced self-equilibriated strain field has a remarkable impact on the mechanical behaviour of the nanotube. Utilization of an appropriate non-linear continuum constitutive relation for graphene leads to exact formulation of the governing equations of SWCNTs. Subsequently, through perturbation analysis, the asymptotic solutions of the initial elastic fields for the SWCNTs are presented. By performing ab initio calculations, the components of the fourth and sixth-order elastic moduli tensors in the constitutive model of graphene needed in this study are computed. 相似文献
120.
Muhammad Ejaz Bhanukiran Sunkara Lakhinder Kamboj Jibao He Vijay T. John Noshir S. Pesika Scott M. Grayson 《Journal of polymer science. Part A, Polymer chemistry》2013,51(15):3314-3322
An efficient and novel one‐pot process is developed to immobilize the atom transfer radical polymerization (ATRP) initiators onto the surface of fully pyrolyzed carbon hard spheres (CHSs) via a radical trapping process from the in situ thermal decomposition of bis(bromomethylbenzoyl)peroxide. The CHSs do not require any additional preparative treatment prior to the initiator immobilization. Styrene and methyl methacrylate are polymerized onto initiator‐immobilized CHSs by surface‐initiated atomic transfer radical polymerization (SI‐ATRP). Samples are characterized using Fourier transform infrared, thermogravimetric analysis, scanning electron microscopy, and transmission electron microscopy. These methods of characterization confirmed that all the CHSs are coated with a uniform layer of grafted polymer. This efficient, one‐pot immobilization of ATRP‐initiators represents an exceptionally simple route for the rapid preparation of various polymer‐coated carbon‐based nanomaterials using SI‐ATRP. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3314–3322 相似文献