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11.
A neutron telescope based on the n–p elastic scattering on H is suggested to investigate the inhomogeneity of neutron fields used for different applications like neutron radiography, biological investigations or dosimetry where the number of neutrons with high energy (above 8 MeV) is negligible. The telescope consists of a thin polyethylene foil and a track etch detector divided by an air gap and placed inside a glass tube which can be evacuated by a simple vacuum pump. The angular and energy resolution of the telescope mostly depend on the diameter of the tube, the length and pressure of the air gap, on the thickness and H content of the radiator and on the type of the track detector. The response of the telescope is characterized by several parameters: the incident angle distribution of protons, the length and the minor diameter distributions of the etched tracks. The response was calculated for several assemblies by a Monte Carlo code and based on the results, three different experimental telescopes were constructed and tested. The most suitable one was selected for routine measurements. 相似文献
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Behaviors of quark matter and strange quark matter which exist in the first seconds of the early Universe in f(R) gravity are studied for Bianchi I and V universes. In this respect, we obtain exact solutions of the modified Einstein field equations by using anisotropy feature of Bianchi I and V space-times. In particular, we investigate exact f(R) functions for Bianchi I as the contribution of strange quark and quark matter. Also, we have concluded that quark matter may contribute to the early acceleration of the universe since quark matter behaves like phantom-type dark energy. Furthermore, obtained f(R) solutions represents early eras of the Universe since f(R) solutions for quark matter coincide with f(R) equations for inflation. From this point, we can reach the conclusion that quarks may be source of the early dark energy of the universe or source of little inflation due to their repulsive force. 相似文献
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Ayta? Gültekin Arzu Ers?z Nalan Y?lmaz Sar??zlü Adil Denizli R?dvan Say 《Journal of nanoparticle research》2010,12(6):2069-2079
Molecular imprinted polymers (MIPs) as a recognition element for sensors are increasingly of interest and MIP nanoclusters have started to appear in the literature. In this study, we have proposed a novel thiol ligand-capping method with polymerizable methacryloylamido-cysteine (MAC) attached to gold–silver nanoclusters, reminiscent of a self-assembled monolayer and have reconstructed surface shell by synthetic host polymers based on molecular imprinting method for recognition. In this method, methacryloylamidoantipyrine–terbium ((MAAP)2–Tb(III)) has been used as a new metal-chelating monomer via metal coordination–chelation interactions and dipicolinic acid (DPA) which is main participant of Bacillus cereus spores used as a model. Nanoshell sensors with templates give a cavity that is selective for DPA. The DPA can simultaneously chelate to Tb(III) metal ion and fit into the shape-selective cavity. Thus, the interaction between Tb(III) ion and free coordination spheres has an effect on the binding ability of the gold–silver nanoclusters nanosensor. The binding affinity of the DPA imprinted nanoclusters has been investigated by using the Langmuir and Scatchard methods, and the respective affinity constants (K affinity) determined were found to be 1.43 × 104 and 9.1 × 106 mol L?1. 相似文献
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A very special case of one of the theorems of the authors states as follows: Let 1a
1a
2... be an infinite sequence of integers for which all the sumsa
i
+a
j
, 1ij, are distinct. Then there are infinitely many integersk for which 2k can be represented in the forma
i
+a
j
but 2k+1 cannot be represented in this form. Several unsolved problems are stated.Dedicated to our friend Professor E. Hlawka on the occasion of his seventieth birthday 相似文献
18.
DIHALOCARBENE ADDITION TO ARYLSUBSTTTUTED VINYL PHOSPHATES UNDER PHASE TRANSFER CATALYTIC CONDITIONS
Imre Petneházy György Keglevich László Tőke 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-2):77-82
Abstract Dihalocarbene addition to aryl-substituted vinyl phosphates was carried out both in solid-liquid and in liquid-liquid two phase systems. The dihalocyclopropane adducts of vinyl phosphates could be obtained in better yield using dihalocarbenes generated by the latter method and no hydrolysis of the vinyl phosphate and of the adduct occurred under these circumstances. Eighteen new vinyl phosphate-dihalocarbene adducts were synthetized and characterized. 相似文献
19.
Zs. M. Jászay I. Petneházy L. Töke 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4)
Abstract During our attempts to prepare asymmetrically substituted carbodiimides of biochemical interest we have observed that phosphoramidate-esters react under phase-transfer conditions with isocyanates giving carbodiimides. 相似文献
20.
Akyuz Sevim Celik Sefa Usta Abdullah Taner Ozel Aysen E. Yılmaz Gözde Yılmaz Salih 《Optics and Spectroscopy》2020,128(8):1318-1327
Optics and Spectroscopy - Endometriosis is a benign gynecologic disorder. It is particularly common among young women and may make pregnancy difficult. In this study molecular level... 相似文献