Crystal structures and growth mechanism for ultrathin films of ionic compound materials: FeO(111) on Pt(111)

The growth and atomic structures of epitaxial iron-oxide films on Pt(111) were studied with scanning tunneling microscopy and high-resolution low-energy electron diffraction. During the initial layer-by-layer growth of FeO(111) four different structures are formed as the coverage increases to 2.5 monolayers, then a three-dimensional growth of Fe3O4(111) islands begins. The structural transformations demonstrate that the relaxations within the FeO(111) films and the Stranski-Krastanov growth mode are induced by electrostatic surface energies, which dominate the energetics of thin film systems made up of ionic compound materials

Medelevvurdering i design- og håndverksfag

Pedagogisk utviklingsarbeid, PPU-deltid Høgskulen i Sogn og Fjordane 201

Magnetocaloric effect in the intermetallic compound DyNi

Magnetic and heat capacity measurements have been carried out on the polycrystalline sample of DyNi which crystallizes in the orthorhombic FeB structure (space group Pnma). This compound is ferromagnetic with a Curie temperature of 59 K. Magnetization-field isotherms at low temperatures shows a step-like behavior characteristic of metamagnetic transitions. The magnetocaloric effect has been measured both in terms of isothermal magnetic entropy change and adiabatic temperature change for various applied magnetic fields. The maximum values of the entropy change and the temperature change are found to be 19 Jkg-1K-1 and 4.5 K, respectively, for a field of 60 kOe. The large magnetocaloric effect is attributed to the field-induced spin-flop metamagnetism occurring in this compound, which has a noncollinear magnetic structure at low fields.Comment: 11 page

Magnetic, magnetocaloric and magnetotransport properties of RSn_{1+x}Ge_{1-x} compounds (R=Gd, Tb, Er; x=0.1)

We have studied the magnetic, magnetocaloric and magnetotransport properties of RSn1+xGe1-x(R=Gd, Tb, Er; x=0.1) series by means of magnetization, heat capacity and resistivity measurements. It has been found that all the compounds crystallize in the orthorhombic crystal structure described by the centrosymmetric space group Cmcm (No. 63). The magnetic susceptibility and heat capacity data suggest that all the compounds are antiferromagnetic. Large negative values of {\theta}p in case of GdSn1.1Ge0.9 and TbSn1.1Ge0.9 indicate that strong antiferromagnetic interactions are involved, which is also reflected in the magnetization isotherms. On the other hand ErSn1.1Ge0.9 shows weak antiferromagnetic interaction. The heat capacity data have been analyzed by fitting the temperature dependence and the values of {\theta}D and {\gamma} have been estimated. Among these three compounds, ErSn1.1Ge0.9 shows considerable magnetic entropy change of 9.5 J/kg K and an adiabatic temperature change of 3.2 K for a field of 50 kOe. The resistivity data in different temperature regimes have been analyzed and the dominant contributions have been identified. All the compounds show small but positive magnetoresistance.Comment: 23 pages,11 figure

Finding the reconstructions of semiconductor surfaces via a genetic algorithm

In this article we show that the reconstructions of semiconductor surfaces can be determined using a genetic procedure. Coupled with highly optimized interatomic potentials, the present approach represents an efficient tool for finding and sorting good structural candidates for further electronic structure calculations and comparison with scanning tunnelling microscope (STM) images. We illustrate the method for the case of Si(105), and build a database of structures that includes the previously found low-energy models, as well as a number of novel configurations.Comment: 4 figures, 1 tabl

Development of the heat and mass transfer model for the study of the temperature traces water droplets in a flame

The heat and mass transfer model is developed with using Ansys Fluent. The typical temperature of gases in the trace of water droplets is determined (initial temperature of gases 1170 К). Several types for the location of water droplets are studied: two successive water droplets; two parallel water droplets; five water droplets in checkerboard order. The hypothesis about gas temperature reduction in the trace of a moving liquid is confirmed

Anti-Müllerian hormone levels in girls and adolescents with Turner syndrome are related to karyotype, pubertal development and growth hormone treatment

STUDY QUESTION In girls and adolescents with Turner syndrome (TS), is there a correlation between serum AMH levels and karyotype, spontaneous puberty and other biochemical markers of ovarian function, or growth hormone (GH) therapy? SUMMARY ANSWER Serum anti-Müllerian hormone (AMH) correlates with karyotype, pubertal development, LH, FSH and are measurable in a higher percentage of TS patients under GH therapy. WHAT IS KNOWN ALREADY Most girls with TS suffer from incomplete sexual development, premature ovarian failure and infertility due to abnormal ovarian folliculogenesis. Serum AMH levels reflect the ovarian reserve in females, even in childhood. STUDY DESIGN, SIZE, DURATION Cross-sectional study investigating 270 karyotype proven TS patients aged 0-20 years between 2009 and 2010. PARTICIPANTS/MATERIALS, SETTINGS, METHODS Studies were conducted at three University Children's hospitals in Europe. Main outcome measures were clinical data concerning pubertal development as well as laboratory data including karyotype, serum AMH, LH, FSH, estradiol (E2), inhibin B and IGF. RESULTS AND THE ROLE OF CHANCE Serum AMH was detectable in 21.9% of all TS girls and correlated strongly with karyotypes. A measurable serum AMH was found in 77% of TS girls with karyotype 45,X/46,XX, in 25% with ‘other' karyotypes and in only 10% of 45,X TS girls. A strong relationship was also observed for measurable serum AMH and signs of spontaneous puberty such as breast development [adjusted odds ratio (OR) 19.3; 95% CI 2.1-175.6; P = 0.009] and menarche (crude OR 47.6; 95% CI 4.8-472.9; P = 0.001). Serum AMH correlated negatively with FSH and LH, but did not correlate with E2 and inhibin B. GH therapy increased the odds of having measurable AMH in TS (adjusted OR 4.1; 95% CI 1.9-8.8; P < 0.001). LIMITATIONS, REASONS FOR CAUTION The cross-sectional design of the study does not allow longitudinal interpretation of the data; for that further studies are needed. High percentage of non-measurable AMH levels in the cohort of TS require categorized analysis. WIDER IMPLICATIONS OF THE FINDINGS Serum AMH levels are a useful marker of the follicle pool and thus ovarian function in pediatric patients with TS. These findings are in line with the published literature. The finding that GH therapy may affect AMH levels is novel, but must be confirmed by future longitudinal studie

Использование IoT-технологий в защите окружающей среды

Большинство дискуссий вокруг феномена Интернета вещей (IoT) обычно сводится к тем потенциальным преимуществам для бизнеса и к тем удобствам для пользователей, которые обеспечивают интеллектуальные устройства и объекты, окружающие нас ежедневно. Однако, каким образом Интернет вещей и индустриальный Интернет вещей (M2M - machine-to-machine), то есть беспроводная передача данных и информации между устройствами и объектами, будет способствовать устойчивому развитию и защите окружающей среды.Most of the discussions around the phenomenon of the Internet of Things (IoT) usually boils down to those potential benefits for the business and to those amenities for users that provide intelligent devices and objects that surround us daily. However, how the Internet of things and the industrial Internet of things (M2M - machine-to-machine), that is, the wireless transmission of data and information between devices and objects, can have a beneficial effect on our lives and will contribute to sustainable development and the protection of the environment on the planet