Magneto and ferroelectric phase transitions in HoMn2O5 monocrystals

From the physical point of view multiferroics present an extremely interesting class of systems and problems. These are essentially of two kinds. One is what are the microscopic conditions, and sometimes constrains, which determine the possibility to combine in one system both magnetic and ferroelectric properties. This turned out to be a quite nontrivial question, and usually, in conventional systems, these two phenomena tend to exclude one another. Why it is the case is an important and still not completely resolved issue. In the present article we report our results from magnetic properties measurements on HoMn2O5 with short discussion about it possible origin

Functionals of Brownian bridges arising in the current mismatch in D/A-converters

Digital-to-analog converters (DAC) transform signals from the abstract digital domain to the real analog world. In many applications, DAC's play a crucial role. Due to variability in the production, various errors arise that influence the performance of the DAC. We focus on the current errors, which describe the fluctuations in the currents of the various unit current elements in the DAC. A key performance measure of the DAC is the Integrated Non-linearity (INL), which we study in this paper. There are several DAC architectures. The most widely used architectures are the thermometer, the binary and the segmented architectures. We study the two extreme architectures, namely, the thermometer and the binary architectures. We assume that the current errors are i.i.d. normally distributed, and reformulate the INL as a functional of a Brownian bridge. We then proceed by investigating these functionals. For the thermometer case, the functional is the maximal absolute value of the Brownian bridge, which has been investigated in the literature. For the binary case, we investigate properties of the functional, such as its mean, variance and density.Comment: 22 pages, 4 figures. Version 2 with Section 3.6 added, and Section 4 revised. To appear in "Probability in the Engineering and Informational Sciences

Transnational Entrepreneurs: Implications of the dual background on opportunity recognition

Transnational entrepreneurs are migrant business owners, traveling abroad for business purposes and engaged in business activities, based on ties to a foreign country. Operating in two countries exposes the entrepreneur to more sources of information and can increase the ability of the entrepreneur to make connections and discover opportunities. Using dual habitus and theory of practice as the main theoretical framework, this paper explores the sources of information of transnational entrepreneurs, and how they are influenced by their unique position of being embedded in two countries at the same time. A case study on transnational entrepreneurs in Skåne is conducted. The data for the study is obtained through the use of general, semi-structured interviews with entrepreneurs, fitting the profile. The critical incidents, leading to opportunity recognition are identified. The findings reveal a clear link between the entrepreneur's transnational background and the recognised opportunity. Furthermore, the results suggest that the main sources of information used to identify opportunities are knowledge corridors and social ties. A link between an individual's transnationalism and perceived competitive advantage is established. The conclusion underlines the value of international experiences and suggests a link between transnationalism and enhanced creativity. Future and practical implications are suggested

Theory of the magnetoeletric effect in a lightly doped high-Tc cuprate

In a recent study Viskadourakis et al. discovered that extremely underdoped La_2CuO_(4+x) is a relaxor ferroelectric and a magnetoelectric material at low temperatures. It is further observed that the magnetoelectric response is anisotropic for different directions of electric polarization and applied magnetic field. By constructing an appropriate Landau theory, we show that a bi-quadratic magnetoelectric coupling can explain the experimentally observed polarization dependence on magnetic field. This coupling leads to several novel low-temperature effects including a feedback enhancement of the magnetization below the ferroelectric transition, and a predicted magnetocapacitive effect.Comment: 5 pages, 4 figure

Проблеми визначення поняття конкурентоздатності підприємства

У статті розглянуто питання, що пов’язані із більш глибшим осмисленням визначення поняття конкурентоздатності підприємства. Узагальнено сучасні теоретичні підходи щодо визначення розглядаємої економічної категорії на основі аналізу пропозицій вітчизняних та зарубіжних вчених. Запропоновано визначення поняття конкурентоздатності підприємства. The article deals with issues related to a deeper comprehension of the definition of enterprise competitiveness. Modern theoretical approaches to the definition examined economic categories based on analysis of the proposed domestic and foreign scientists are generalized. The author`s definition of the competitiveness of enterprise is proposed

Оцінка впливу зовнішніх факторів на рівень конкурентоспроможності підприємств з виробництва готових металевих виробів

http://vsed.oneu.edu.uaУ статті проаналізовано комбіноване використання методів багатовимірного статистичного аналізу: методу головних компонент і таксономічного методу при оцінці впливу зовнішніх факторів на рівень конкурентоспроможності підприємств із виробництва готових металевих виробів. Отримано кількісну оцінку впливу зовнішніх факторів конкурентоспроможності підприємства мезорівня. Надано рекомендації підприємству ТОВ «Южний електротехнічний завод». The article analyzes the combined use of multivariate statistical analysis: principal component analysis and taxonomic method for assessing the impact of external factors on the level of competitiveness of enterprises for the production of fabricated metal products. A quantitative assessment of the impact of external factors mesolevel enterprise competitiveness were obtained. Recommendations for the enterprise « South electrical plant» on ways to improve the overall level of competitiveness were given

Місцеві органи державної влади як зовнішній фактор конкурентоспроможності підприємств

У статті розглянуто питання, пов’язані з необхідністю більш глибокого осмислення зовнішніх факторів конкурентоспроможності підприємства. За результатами дослідження автором розроблено власну класифікацію зовнішніх факторів конкурентоздатності підприємства. Досліджено та проаналізовано вплив місцевих органів державної влади на конкурентоспроможність підприємства. The questions connecting with the necessity of deeper understanding of the external competitiveness factors are researched in the article. There are developed its own classification of the external factors of competitiveness of enterprises on the basis of author’s investigations. The influence of local authorities on the competitiveness of enterprises is examined and analyzed

A 28-nm CMOS 1 V 3.5 GS/s 6-bit DAC with signal-independent delta-I noise DfT scheme

This paper presents a 3.5GSps 6-bit current-steering DAC with auxiliary circuitry to assist testing in a 1V digital 28nm CMOS process. The DAC uses only thin-oxide transistors and occupies 0.035mm2, making it suitable to embedding in VLSI systems, e.g. FPGA. To cope with the IC process variability, a unit element approach is generally employed. The 3 MSBs are implemented as 7 unary D/A cells and the 3 LSBs as 3 binary D/A cells, using appropriately reduced number of unit elements. Furthermore, all digital gates only make use of two basic unit blocks: a buffer and a multiplexer. For testing, a memory block of 5kbits is placed on-chip, which is externally loaded in a serial way but internally read in an 8x time-interleaved way. The memory is organized around 48 clocked 104-bit shift-registers. It keeps the resulting switching disturbances signal-independent and hence avoids inducing output non-linearity errors, even when a common power supply is shared with the DAC. This novelty allows reliable testing of the DAC core, while avoiding performance limitation risks of handling high-speed off-chip data streams. The DAC SFDR>40dB bandwidth is 0.8GHz, while the IM