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1.
S. M. Kormali D. L. Swindle E. A. Schweikert 《Journal of Radioanalytical and Nuclear Chemistry》1976,31(2):413-436
A survey has been made on the application of charged particle activation analysis for the detection of traces of medium Z
elements (40≤Z≤58, 72, 74) using protons and deuterons of 20 MeV,3He and4He ions of 40 MeV. The product nuclides considered were γ-ray emitting radioisotopes with half lives ranging from 10 min to
3 days. Based on the thick target yields obtained, proton activation was found to provide an optimum compromise between sensitivity
and selectivity. 相似文献
2.
Background
Growth hormone (GH) plays an incompletely understood role in the development of the central nervous system (CNS). In this study, we use transgenic mice expressing a growth hormone antagonist (GHA) to explore the role of GH in regulating postnatal brain, spinal cord and body growth into adulthood. The GHA transgene encodes a protein that inhibits the binding of GH to its receptor, specifically antagonizing the trophic effects of endogenous GH. 相似文献3.
KM Varier AM Vinodkumar NVSV Prasad PV Madhusudhana Rao DL Sastry Lagy T Baby MC Radhakrishna NG Puttaswamy JJ Das P Sugathan N Madhavan AK Sinha DO Kataria 《Pramana》1999,53(3):529-533
Large enhancements have been observed in the sub-barrier fusion cross sections for Ti+Ni systems in our previous studies.
Coupled channel calculations incorporating couplings to 2+ and 3− states failed to explain these enhancements completely. A possibilty of transfer channels contributing to the residual enhancements
had been suggested. In order to investigate the role of relevant transfer channels, measurements of one- and two-nucleon transfer
were carried out for 46,48Ti+61Ni systems. The present paper gives the results of these studies. 相似文献
4.
WYETH Paul 《中国科学:化学》2010,(3)
Silks represent some of the most precious ancient and historic textile artefacts in collections worldwide.Their optimum preservation demands an appreciation of their characteristics.One important concern,especially with regard to ancient Chinese silks,is whether the fabrics have been degummed.Silks with remnant sericin gum coating the fibroin fibres would require different conservation protocol.In previous research on aged silks,the presence of sericin has been inferred from amino acid analysis of hydrolysa... 相似文献
5.
[formula: see text] Iron salts efficiently catalyze the Doyle-Kirmse reaction of allyl sulfides with (trimethylsilyl)diazomethane and ethyl diazoacetate in dichloroethane at 83 degrees C. Competitive dimerization is less of a problem with (trimethylsilyl)diazomethane than with ethyl diazoacetate. Good results are obtained using only 1.5 equiv of (trimethylsilyl)diazomethane, even without slow addition. Phosphine ligands affect the kinetics, but not the diastereoselectivity. Dppe and BINAP lead to higher yields than dppp, but no enantioselection was detected with R-(+)-BINAP. 相似文献
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7.
Summary In this paper we consider a modification of Ziff, Gulari and Barshad's (1986) model of oxidation of carbon monoxide on a catalyst surface in which the reactants are mobile on the catalyst surface. We find regions in the parameter space in which poisoning occurs (the catalyst surface becomes completely occupied by one type of atom) and another in which there is a translation invariant stationary distribution in which the two atoms have positive density. The last result is proved by exploiting a connection between the particle system with fast stirring and a limiting system of reaction diffusion equations. 相似文献
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9.
S. A. Dabney D. L. Swindle J. N. Beck G. Francis E. A. Schweikert 《Journal of Radioanalytical and Nuclear Chemistry》1973,16(2):375-383
An analytical method is described for the determination of trace amounts of sulfur by charged particle activation analysis.
The method consists of proton irradiation followed by a rapid radiochemical separation of the product nuclide,34m Cl. This procedure has been applied to a number of pure metal samples which range in sulfur content from 0.3 to 30 ppm. All
analyses were repeated several times to ensure consistent results and to better evaluate experimental detection limits and
systematic errors. The results indicate that sulfur determinations can be performed at a concentration of less than 1.0 ppm.
Activation curves are presented for the reactions S(d,x)34mCl, S(p,x)34mCl, and the interfering reaction35Cl(p, pn)34mCl.
In memoriam. 相似文献
10.
The (3)He activation method for oxygen determination was applied to chalcogenide materials such as Ge(28)Sb(12)Se(60) and Ge(33)As(12)Se(55). Attention was focused on the optimization of the (3)He bombardment energy for non-destructive oxygen determination and the validity of the post-irradiation chemical etch used for removing surface oxygen contamination. The procedure developed was tested on a series of chalcogenide glasses. The detection limit for this non-destructive technique using ~6-MeV (3)He is estimated at ~1 ppm of oxygen. 相似文献