Thermal Conductivity and Specific Heat of the Spin-Ice Compound Dy2_2Ti2_2O7_7: Experimental Evidence for Monopole Heat Transport

Elementary excitations in the spin-ice compound Dy$_2$Ti$_2$O$_7$ can be described as magnetic monopoles propagating independently within the pyrochlore lattice formed by magnetic Dy ions. We studied the magnetic-field dependence of the thermal conductivity {\kappa}(B) for B || [001] and observe clear evidence for magnetic heat transport originating from the monopole excitations. The magnetic contribution {\kappa}_{mag} is strongly field-dependent and correlates with the magnetization M(B). The diffusion coefficient obtained from the ratio of {\kappa}_{mag} and the magnetic specific heat is strongly enhanced below 1 K indicating a high mobility of the monopole excitations in the spin-ice state.Comment: 5 pages, 4 figure

Особенности разряда на границе раздела твердых слоистых диэлектриков

Установлена связь величины разрядного напряжения на границе раздела твердых слоистых диэлектриков от длины разрядного расстояния. Обнаружено явление заглубления канала разряда в диэлектрик, прилегающий к границе раздела, выход его на внешнюю поверхность с последующим развитием по воздуху

Профессор Ю. В. Петров (1939-2011)

Памяти Юрия Владимировича Петрова - доктора философских наук, профессора Томского политехнического университета

Микропроцессорный блок управления полупроводниковым коммутатором для накачки CUBR-лазера

Разработка приборов, позволяющих проводить обработку материалов с помощью высококонцентрированных потоков энергии, является весьма актуальной задачей. Одним из классов таких приборов являются лазерные системы, которые могут применяться как в технике, так и в медицине. Разработка устройств, позволяющих формировать «силовой» пучок с заданной конфигурацией позволит значительно увеличить скорость обработки материалов и минимизировать побочные действия при использовании в медицинских целях. В работе представлено подобное устройство, позволяющее изменять распределение интенсивности по пучку с использованием активных оптических систем с усилителями яркости на парах металлов. В качестве усилителя яркости использовался CuBr-лазер с тиратронным источником питания с импульсным зарядом рабочей емкости. Мощность источника питания варьировалась от 900 до 1500 Вт. Проведены исследования зависимости контраста получаемых изображений и влияние параметров используемого дисплея

Technique of definition of cracking resistance characteristics of metal plates and envelopes of small thickness

The technique of cracking resistance tests of metal plates of small thickness is given. Features of such tests, among which are occurrence of warp in the places of fastening of plates, occurrence of waves because of loss of stability at out-centre loading are shown. Ways to eliminate these shortcomings with the help of special equipment are specified. Tests by the proposed methods allow to make recommendations for technology and choice of steels at creation of valve tapes

Summaries

Приведены рефераты статей данного номера на английском языке

Newspaper coverage of health issues in Nigeria : the frequency of reporting malaria, HIV/AIDS and polio and the effect of seeking health information on the health behaviours of newspaper readers.

The prevalence of various health problems in Nigeria and their devastating consequences on the socio-economic status of the nation is such that seems to have defied all logics. The Nigerian government at various levels and many international health and funding agencies continue to make efforts to improve the health status of the individual members of Nigerian society and the health sector at large. However, scholars have continued to identify and emphasise the strategic position and the need to use the media as a complementary approach to advance the health sector and to achieve good health outcomes among members of society. This study, therefore, examines the coverage of health issues by Nigerian newspapers, emphasising the degree of attention given to HIV/AIDS, malaria, polio and the northern region. The study further examines the relationship between dissemination of health information by Nigerian newspapers and the health behaviours of newspaper readers and the challenges being encountered by health reporters in the field of health reporting in Nigeria. With a comprehensive literature review underpinning priming and framing within the framework of agenda setting theory; and a triangular methodological approach of content analysis of 844 editions of four national newspapers from 2010-2013, survey and in-depth interviews, the study finds a moderate coverage of HIV/AIDS, malaria, polio in Nigerian newspapers in relation to other diseases studied. These three diseases are also reported in relation to northern Nigeria more than other regions included in this study. But in general, Nigerian newspapers have not given prominent coverage to health issues in their leads, editorials and other important pages. This finding suggests that Nigerian newspapers appear to give prominent attention to other issues which, as noted by health reporters interviewed, include politics and economy, over health issues. Given that Nigerian newspapers have not given prominent coverage to health issues, this suggests that Nigerian newspapers may have less influence in directing the attention of the Nigerian government towards making health a top priority in the government agenda. The study also shows that dissemination of health information by Nigerian newspapers correlates with an improvement in the health behaviours of newspaper readers in the country. Furthermore, interviewed 13 newspapers health reporters across the national newspapers in Nigeria and find that health reporters generally face a wide range of challenges due to the specialised and technical nature of health reporting. Health reporters who were trained in health and sciences demonstrate better expertise and skills in health reporting in Nigeria than health reporters who were trained in the arts and social sciences. This finding suggests that health and science training has a major influence in health reporting in Nigeria. The finding may further imply that health and science background may be considered important in employing health reporters for the field of health reporting given the technical nature and some degree of health and science expertise required for optimal job performance in the field

Анализ эффективности проведения кислотного гидроразрыва пласта на месторождениях Западной Сибири

Объектом исследований является кислотный гидравлический разрыв пласта (КГРП), его эффективность, изменения, происходящие в призабойной зоне пласта. Целью данной выпускной квалификационной работы является анализ эффективности КГРП на месторождениях Западной Сибири. В результате работы проведен сбор, обобщение, переработка информации по технологии проведения КГРП и жидкостям разрыва. Рассмотрены нефтекислотные эмульсии, их преимущества и недостатки перед другими жидкостями разрыва. Проведена оценка параметров трещины для того, чтобы оценить расход кислоты с учетом пористости и проницаемости пласта.The object of research is acid hydraulic fracturing (AHF), its effectiveness, changes in bottom-hole formation zone. The purpose of this final qualifying work is to analyze the efficiency AHF in the fields of Western Siberia. As a result of work carried out the collection, collation, processing of information on the technology of the AHF and liquids break. Emulsion are considered, their advantages and disadvantages over other liquids divide