scholarly journals CHARGE COMPENSATION IN POTASSIUM POLYFERRITE AT DOPING WITH FOUR-CHARGED IONS

Author(s):  
Lyubov G. Anikanova ◽  
Zoya G. Malysheva ◽  
Tatyana N. Sudzilovskaya ◽  
Nikolai V. Dvoretskii

In order to clarify the mechanism of charge compensation with the introduction of additives of four-charged ions ions into the composition of catalytically active potassium polyferrites, mixtures with different molar ratios KFeO2: Fe: Fe2O3: MeO2, where Me is Ce, Ti, Zr, were calcined in a muffle furnace in a stream of nitrogen for 4 - 6 h at a temperature of 970 K. As a result, single-phase potassium polyferrites with the β˝-alumina-type structure were obtained, which was confirmed by X-ray diffractometry. Based on the measurement of the electronic conductivity of doped polyferrites, the determination of the content of two-charged and three- charged iron, it has been established that the introduction of four-charged ions into the structure of a β˝-alumina type polyferrite occurs in accordance with the charge compensation mechanism described by the formula K2FeII1+qFeIII10-2qMeqIVO17, where q is a coefficient characterizing the content of the additive of four-charged ion. The above mechanism is implemented by reducing part of the three- charged iron while maintaining the initial content of alkali metal. The effect of the nature of the alloying ion on the composition and the electronic conductivity of the obtained polyferrite is shown. The destabilizing effect of four-charged ions, which is expressed in facilitating the emission of alkali metal from the crystal lattice of polyferrite, has been revealed. It is shown that the ratio of various charge forms of iron can be controlled within wide limits not only by changing the redox properties of the atmosphere, but also by introducing various additives into the potassium polyferrite structure. A violation of single-phase cerium-doped polyferrites was noted when reaching a value of q of more than 0.6. For polyferrites doped with titanium or zirconium, the structure was maintained throughout the entire range of q values studied.

2014 ◽  
Vol 84 (Supplement 1) ◽  
pp. 25-29 ◽  
Author(s):  
Guangwen Tang

Humans need vitamin A and obtain essential vitamin A by conversion of plant foods rich in provitamin A and/or absorption of preformed vitamin A from foods of animal origin. The determination of the vitamin A value of plant foods rich in provitamin A is important but has challenges. The aim of this paper is to review the progress over last 80 years following the discovery on the conversion of β-carotene to vitamin A and the various techniques including stable isotope technologies that have been developed to determine vitamin A values of plant provitamin A (mainly β-carotene). These include applications from using radioactive β-carotene and vitamin A, depletion-repletion with vitamin A and β-carotene, and measuring postprandial chylomicron fractions after feeding a β-carotene rich diet, to using stable isotopes as tracers to follow the absorption and conversion of plant food provitamin A carotenoids (mainly β-carotene) in humans. These approaches have greatly promoted our understanding of the absorption and conversion of β-carotene to vitamin A. Stable isotope labeled plant foods are useful for determining the overall bioavailability of provitamin A carotenoids from specific foods. Locally obtained plant foods can provide vitamin A and prevent deficiency of vitamin A, a remaining worldwide concern.


2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Mingming Yang ◽  
Longlong Wang ◽  
Xiaofen Qiao ◽  
Yi Liu ◽  
Yufan Liu ◽  
...  

Abstract The defects into the hexagonal network of a sp2-hybridized carbon atom have been demonstrated to have a significant influence on intrinsic properties of graphene systems. In this paper, we presented a study of temperature-dependent Raman spectra of G peak and D’ band at low temperatures from 78 to 318 K in defective monolayer to few-layer graphene induced by ion C+ bombardment under the determination of vacancy uniformity. Defects lead to the increase of the negative temperature coefficient of G peak, with a value almost identical to that of D’ band. However, the variation of frequency and linewidth of G peak with layer number is contrary to D’ band. It derives from the related electron-phonon interaction in G and D’ phonon in the disorder-induced Raman scattering process. Our results are helpful to understand the mechanism of temperature-dependent phonons in graphene-based materials and provide valuable information on thermal properties of defects for the application of graphene-based devices.


Fuel ◽  
2022 ◽  
Vol 307 ◽  
pp. 121837
Author(s):  
Samara Soares ◽  
Gabriel M. Fernandes ◽  
Liz M.B. Moraes ◽  
Alex D. Batista ◽  
Fábio R.P. Rocha

2017 ◽  
Vol 14 (2) ◽  
pp. 55-68 ◽  
Author(s):  
Rita Bužinskienė

AbstractIn accordance with generally accepted accounting standards, most intangibles are not accounted for and not reflected in the traditional financial accounting. For this reason, most companies account intangible assets (IAs) as expenses. In the research, 57 sub-elements of IAs were applied, which are grouped into eight main elements of IAs. The classification of IAs consists in two parts of assets: accounting and non-accounting. This classification can be successfully applied in different branches of enterprises, to expand and supplement the theoretical and practical concepts of the company's financial management. The article proposes to evaluate not only the value of financial information for IAs (accounted) but also the value of non-financial information for IAs (non-accounted), thus revealing the true value of IAs that is available to the companies of Lithuania. It names a value of general IAs. The results of the research confirmed the IA valuation methodology, which allows companies to calculate the fair value of an IA. The obtained extended IAs valuation information may be valuable to both the owners of the company and investors, as this value plays an important practical role in assessing the impact of IAs on the market value of companies.


2017 ◽  
Vol 96 ◽  
pp. 13-26 ◽  
Author(s):  
G. Plusquellec ◽  
M.R. Geiker ◽  
J. Lindgård ◽  
J. Duchesne ◽  
B. Fournier ◽  
...  

1986 ◽  
Vol 71 ◽  
Author(s):  
I. Suni ◽  
M. Finetti ◽  
K. Grahn

AbstractA computer model based on the finite element method has been applied to evaluate the effect of the parasitic area between contact and diffusion edges on end resistance measurements in four terminal Kelvin resistor structures. The model is then applied to Al/Ti/n+ Si contacts and a value of contact resistivity of Qc = 1.8×10−7.Ωcm2 is derived. For comparison, the use of a self-aligned structure to avoid parasitic effects is presented and the first experimental results obtained on Al/Ti/n+Si and Al/CoSi2/n+Si contacts are shown and discussed.


2020 ◽  
Vol 2 (2) ◽  
pp. 95-106
Author(s):  
Indrawaty Sitepu ◽  
Nurmely Violeta Sitorus

Kangkung hidroponik menjadi kangkung rendang merupakan kegiatan yang dapat meningkatkan nilai tambah, menghasilkan produk yang dapat dikonsumsi, serta menambah pendapatan dan keuntungan produsen.Tujuan penelitian untuk menguraikan apa saja tahapan pengolahan kangkung hidroponik menjadi kangukung rendang, menganalisis biaya produksi, penerimaan, dan pendapatan, menganalisis nilai tambah pengolahan kangkung hidroponik menjadi kangkung rendang, menganalisis apakah usaha pengolahan kangkung hidroponik menjadi kangkung rendang layak diusahakan. Penelitian ini dilakukan di Jalan Bromo lorong Amal Medan Denai Kota Medan. Penentuan daerah penelitian dilakukan secara purposive, Metode pengambilan sampel secara sensus yaitu usaha Syifa Hidroponik dengan pengambilan data ulangan selama 2,5 bualan sebanyak 10 kali ulangan. Hasil penelitian: 1) Tahapan  pengolahan kangkung hidroponik menjadi kangkung rendang yaitu:  Penyediaan bahan baku kangkung hidroponik, kangkung dihaluskan, pengadonan kangkung, telur ayam, tepung beras dan garam, kangkung dikukus, kangkung didinginkan, dipotong-potong, digoreng, pemasakan bumbu rendang, pencampuran kangkung yang digoreng dengan bumbu rendang dan pemasaran. Total biaya pengolahan kangkung hidroponik menjadi kangkung rendang untuk sekali produksi sebesar Rp 545.291,83, penerimaan sebesar Rp 1.500.000,00, per sekali produksi dan pendapatan sebesar Rp 954.708,17 per sekali produksi. Nilai tambah yang dihasilkan dari pengolahan kangkung hidroponik menjadi kangkung rendang tergolong tinggi dengan rasio nilai tambah 75,31% > 50%.Usaha pengolahan kangkung hidroponik menjadi kangkung rendang layak untuk diusahakan dengan nilai R/C rasio 2,75 > 1.  Abstract  Hydroponic water spinach into rendang water spinach is an activity that can increase added value, produce edible products, as well as increase producer income and profits. The purpose of the research is to describe what are the stages of processing hydroponic water spinach into rendang kangukung, analyze production costs, revenue, and income, analyze added value of processing hydroponic water spinach into rendang water spinach, analyzing whether the business of processing hydroponic water spinach into rendang water spinach is worth the effort. This research was conducted in Jalan Bromo Amal Medan Denai alley Medan City. Determination of the study area was done purposively, census sampling method that is Syifa Hydroponic business with retrieval data retrieval for 2.5 boasting as many as 10 replications. The results of the study: 1) The stages of processing hydroponic water spinach into rendang water spinach, namely: Provision of raw materials for hydroponic water spinach, crushed water spinach, stirring water spinach, chicken eggs, rice flour and salt, steamed water spinach, water spinach water spinach, cut into pieces, fried, fried spicy water spinach, cooking water spinach kale, chicken egg, rice flour and salt, steamed water spinach, water spinach kangkung cooled, cut, fried, cooking spices, rendang, mixing fried kale with spicy rendang and marketing. The total cost of processing hydroponic water spinach into rendang water spinach for one production is Rp. 545,291.83, revenue is Rp. 1,500,000.00, per production and income is Rp. 954,708.17 per production. The added value generated from the processing of hydroponic water spinach into rendang water spinach is classified as high with a value added ratio of 75.31%> 50%. The business of processing hydroponic water spinach into rendang water spinach is feasible to be cultivated with an R / C ratio of 2.75> 1.  


Sign in / Sign up

Export Citation Format

Share Document