Evaluation and testing of advanced low-voltage power supplies

A distinguishing feature of the LHC detectors is the enormous number of front end electronics channels in all the sub-detectors. Low voltage power supply systems in the range of multi kilowatts are required to bias such electronics. These power supplies will be located in the cavern close to the detector where stray magnetic field and radiation are present. The main advantage of this topology is the reduction of the length cable needed to carry power to the electronics. This paper describes results on electrical and environmental tests performed on sample equipment. Descriptions of the objects and methods of tests are given

Spin dependent photoelectron tunnelling from GaAs into magnetic Cobalt

The spin dependence of the photoelectron tunnel current from free standing GaAs films into out-of- plane magnetized Cobalt films is demonstrated. The measured spin asymmetry (A) resulting from a change in light helicity, reaches +/- 6% around zero applied tunnel bias and drops to +/- 2% at a bias of -1.6 V applied to the GaAs. This decrease is a result of the drop in the photoelectron spin polarization that results from a reduction in the GaAs surface recombination velocity. The sign of A changes with that of the Cobalt magnetization direction. In contrast, on a (nonmagnetic) Gold film A ~ 0%

System Integration Issues of DC to DC converters in the sLHC Trackers

The upgrade of the trackers at the sLHC experiments requires implementing new powering schemes that will provide an increased power density with reduced losses and material budget. A scheme based on buck and switched capacitors DC to DC converters has been proposed as an optimal solution. The buck converter is based on a power ASIC, connected to a custom made air core inductor. The arrangement of the parts and the board layout of the power module are designed to minimize the emissions of EMI in a compact volume, enabling its integration on the tracker modules and staves

Відображення розвитку науки України та Євросоюзу в реферативній базі даних SCOPUS

Досліджено публікаційну активність України та Євросоюзу за галузями науки. Розглянуто динаміку кількості публікацій, що припадають на одного дослідника впродовж 1996-2010 рр. Виконано порівняння відображення кількості публікацій БД Scopus у ВВП та витратах на НДДКР країн в розрахунку на кожен 1 млн. дол. США.Исследована публикационная активность Украины и Евросоюза по отраслям науки. Рассмотрена динамика количества публикаций, которые приходятся на одного исследователя на протяжении 1996–2010 гг. Сделано сравнение отображения количества публикаций БД Scopus в ВВП и затратах на НДДКР стран в расчете на каждый 1 млн. дол. США.The publication activity by fields of science of Ukraine and the European Union was investigated. The dynamics of the number of publications per 1 researcher was considered during 1996–2010 years. Countries comparison by the number of publications reflecting in GDP and R&D expenditures per 1 million U.S. dollars measurements in the abstract database Scopus was done

Poly(dimethylsiloxane) as a pre-coating in layer-by-layer films containing phosphotungstate nanoclusters electrochemically sensitive toward s-triazines

One of the major advantages of the Layer-by-Layer (LbL) deposition technique is the possible control of molecular architecture, not only to achieve optimized properties but also to seek synergy among different materials. In this study, LbL films containing nanoclusters of a Keggin type polyoxometalate, phosphotungstic acid (HPW), alternated with the polycation poly(allylamine hydrochloride) (PAH) were deposited on indium-tin oxide (ITO) substrates. The electrochemical properties of the hybrid LbL film investigated in acidic conditions indicated no significant desorption of HPW, when a layer of poly(dimethylsiloxane) terminated with 3-aminopropyl groups (PDMS) was previously deposited on the ITO substrate. Such effect occurred because PDMS prevents desorption of HPW from the hybrid film, as shown by X-ray Photoelectron Spectroscopy (XPS) analyses. The porous structures of the films were revealed by Fourier transform infrared reflection absorption spectroscopy, scanning electron microscopy and XPS. PDMS/PAH as a pre-coating allowed the HPW/PAH films to be sensitive to the electrochemical detection of the triazines atrazine and melamine. In conclusion, the precise control of the LbL films architecture is important to develop opportunities for new applications. © 2014 The Royal Society of Chemistry.One of the major advantages of the Layer-by-Layer (LbL) deposition technique is the possible control of molecular architecture, not only to achieve optimized properties but also to seek synergy among different materials. 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The rapid formation of functional monolayers on silicon under mild conditions

We report on an exceedingly mild chemical functionalization of hydrogen-terminated Si(100) with unactivated and unprotected bifunctional α,ω-dialkynes. Monolayer formation occurs rapidly in the dark, and at room temperature, from dilute solutions of an aromatic-conjugated acetylene. The method addresses the poor reactivity of p-type substrates under mild conditions. We suggest the importance of several factors, including an optimal orientation for electron transfer between the adsorbate and the Si surface, conjugation of the acetylenic function with a π-system, as well as the choice of a solvent system that favors electron transfer and screens Coulombic interactions between surface holes and electrons. The passivated Si(100) electrode is amenable to further functionalization and shown to be a viable model system for redox studies at non-oxide semiconductor electrodes in aqueous solutions