Identification of main contributions to conductivity of epitaxial InN

Complex effect of different contributions (spontaneously formed In nanoparticles, near-interface, surface and bulk layers) on electrophysical properties of InN epitaxial films is studied. Transport parameters of the surface layer are determined from the Shubnikov-de Haas oscillations measured in undoped and Mg-doped InN films at magnetic fields up to 63 T. It is shown that the In nanoparticles, near-interface and bulk layers play the dominant role in the electrical conductivity of InN, while influence of the surface layer is pronounced only in the compensated low-mobility InN:Mg films

Student Attitude to Internet Search Engines: Navigation and Optimization Problems

The article relevance. Currently, the world is rapidly undergoing the process of Informatization of all aspects of society, the development and introduction of new information technologies. This highlights the need for further reflection and research on the development of the Internet and its opening opportunities for people. The aim of the research is to study the peculiarities of the attitude of students to search and recommendation services on the Internet. Research methods: as a research method, we used a questionnaire survey as a method of collecting primary information, which allows us to identify various aspects related to the attitude of students to search and recommendation systems on the Internet. Research results: the article examines the specifics of Russian search and recommendation systems, students' attitude to these services, and their place in their lives. The novelty and originality of the research lies in the fact that for the first time the search and recommendation services of the Internet space were studied. It is shown that these services were initially developed in the sphere of culture and gradually began to spread to other spheres of people's life, which attracted e-Commerce figures. It is revealed that those students who discovered search and recommendation services a few years ago still use them to choose leisure activities. It is shown that students still identify some disadvantages of these systems: inaccurate recommendations, a large number of questions to determine preferences. There is some distrust to new Internet technologies among those who are used to relying on their intuition when choosing. It is determined that students often use search and recommendation services, since in most cases gadgets help them spend their free time, have fun: read a book, watch a movie, listen to music. It is revealed that the majority of students trust Internet services, although they are not always satisfied with the recommendations. It is shown that the level of student-user confidence in traditional advertising and marketing decreases simultaneously. It is determined that from the point of view of students, today not only printed versions of Newspapers, traditional radio, but even mass broadcast television are losing ground before the Internet as the most promising communication channel. Practical significance: the data Obtained in this work can be used in marketing research, economic Sciences, advertising psychology, as well as for further theoretical development of this issue

АТОМНО-ЭМИССИОННЫЙ АНАЛИЗ ВЫСОКОЧИСТОГО ОКСИДА ВОЛЬФРАМА И КРИСТАЛЛОВ ВОЛЬФРАМАТА КАДМИЯ C ИОНООБМЕННЫМ ОТДЕЛЕНИЕМ ВОЛЬФРАМА

Determination of impurities in tungsten oxide (WO3) and cadmium tungstate crystals CdWO4 (CWO) was performed by atomic emission spectrometry with a two-jet arc plasma (TJP-AES) after ion exchange tungsten separation. Tungsten metal obtained under reduction of WO3 and CWO by hydrogen was dissolved in 30 % hydrogen peroxide solution and passed through a cation exchange column. Impurities adsorbed on the column were eluted by nitric acid solution and evaporated on graphite powder. Element concentrations in graphite concentrate of impurities were determined by TJP-AES. The technique developed allows the determination of Ag, Al, Ba, Bi, Ca, Co, Cr, Cu, Dy, Eu, Fe, Ga, Gd, Mg, Mn, Ni, Sm, and Ti with detection limits in the range of 0.5-500 (WO3) and 0.3-350 (CWO) ng/g.Keywords: tungsten oxide, cadmium tungstate, reduction by hydrogen, ion exchange chromatography, two-jet arc plasma, impurities, atomic emission spectrometry.(Russian)DOI: http://dx.doi.org/10.15826/analitika.2013.17.1.006 N.P. Zaksas, L.N. Komissarova, P.S. Galkin, A.P. Zubareva Nikolaev Institute of Inorganic Chemistry SB RAS, Novosibirsk, Russian FederationОпределение примесей в оксиде вольфрама (WO3) и кристаллах вольфрамата кадмия CdWO4 (CWO) проводили методом атомно-эмиссионной спектрометрии с двухструйной дуговой плазмой (ДДП-АЭС) после ионообменного отделения вольфрама. Металлический вольфрам, полученный при восстановлении WO3 и CWO водородом, растворяли в 30 % растворе пероксида водорода и пропускали через катионообменную колонку. Примеси, адсорбированные на колонке, элюировали раствором азотной кислоты и упаривали на графитовый порошок. Содержание элементов в графитовом концентрате микропримесей определяли методом ДДП-АЭС. Разработанная методика позволяет определять Ag, Al, Ba, Bi, Ca, Co, Cr, Cu, Dy, Eu, Fe, Ga, Gd, Mg, Mn, Ni, Sm и Ti с пределами обнаружения 0.5-500 (WO3) и 0.3-350 (CWO) нг/г.Ключевые слова: оксид вольфрама, вольфрамат кадмия, восстановление водородом, ионообменная хроматография, двухструйная дуговая плазма, примеси, атомно-эмиссионный анализ.DOI: http://dx.doi.org/10.15826/analitika.2013.17.1.00