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  • Author or Editor: N. Krasnov x
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Abstract  

Surface activation with charged particles is a suitable method for the determination of wear in machine parts. Investigations of the dependence of the yield of major radioactive isotopes on particle energy and of the distribution of these isotopes along the depth of the activated layer are reported. Activation and activity measurement conditions for common materials of construction are suggested. Calculation procedures for converting activity values into absolute wear data and for evaluating methodical errors are given.

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Abstract  

A method is described for the quantitative determination of the distribution of impurities, utilizing charged particles. Experimental data obtained by activation with 7.5 MeV3He ions are reported on the distribution of oxygen in Ge and Nb samples.

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Abstract  

It is shown that three different approaches to calibration technique based on the use of average cross-section, equivalent target thickness and thick target yield are adequate. Using the concept of thick target yield, a convenient charged particle activation equation is obtained. The possibility of simultaneous determination of two elements impurities, from which the same isotope is formed, is pointed out. The calibration technique, in which thin standard is used but activation curve is not required, is discussed.

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Abstract  

The influence of activation of Ta by secondary neutrons on the results of proton activation instrumental analysis of W in Ta is described. It is shown that the detection limit of W in Ta using 11 MeV protons cannot be lower than 3 ppm.

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Abstract  

Procedures for determining traces of calcium, titanium, vanadium, chromium, iron, copper, niobium, molybdenum and tungsten in tantalum are described utilizing 11 MeV proton activation. The instrumental method of analysis with the use of a Ge(Li) detector and the radiochemical separation of the corresponding fractions are described. The formula for the calculation of the concentration of traces with the use of thick target yields is given. Experimental data on the thick target yields of radioisotopes44Sc,52Mn,56Co,65Zn,93mMo,96Tc are presented. Based on the experimental data, the detection limits are estimated at 1–10 ppb for the above mentioned metal traces in tantalum. The successful solution of the task of the simultaneous determination of nine elements in tantalum confirms the wide applicability of proton activation analysis.

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Abstract  

Procedures are described for determining traces of titanium in scandium, vanadium in titanium, zinc in copper and tungsten in tantalum, utilizing activation with 11 Me V protons. Experimental data on48V,51Cr,66Ga and182Re yields and analytical sensitivities are reported.

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Abstract

The purpose of this work is to develop a dosing system that provides high-quality bunch planting of watermelon seeds with a given seeding rate and their uniform distribution over the plant nutrition area. It is important to know how many seeds it is needed in the bunch in order to provide the required number of plants in a certain plant nutrition area. The method to achieve this goal is to determine the optimal operating modes for the seeding device, in which the dosing system would supply the seed to the bunch without gaps, searching for dependencies that can determine the required number of the sown seeds in the bunch, taking into account their germination and the number of plants specified by agrotechnical conditions in every bunch. Based on the obtained dependencies, determining the probability of bunches with various numbers of plants, while sowing four seeds in the seedbed with maximum field germination, the design of experimental seed discs is proposed, allowing bunch planting and germination due to easy destruction of the soil crust. At the same time, optimal use of the nutritional area for plants, and, consequently, an increase in the yield of the sown crops is ensured. Experimental seed discs with a group arrangement of suction holes (four cells each) will provide bunch planting of watermelon seeds in accordance with agrotechnical requirements.

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