37,488 research outputs found
The development of high field magnets utilizing Bi-2212 wind & react insert coils
No full textWind & react Bi-2212 inserts have been manufactured and tested inside a wide-bore NbTi-Nb3Sn magnet providing a background field up to 20T at 4.2K. A pair of six-layer concentric coils both achieved critical currents of 350 A (JE = 200 A/mm2) in a 20T background field. A thicker 14-layer insert made from 119m of round wire had a critical quench current IQ of 287A (JE = 162 A/mm2) at the same field and contributed to a combined central field of 22.5 T. This is a record for a fully superconducting magnet at 4.2 K. The 14-layer coil, equipped with an external protective shunt, was used for an extensive series of quench measurements and endured >150 quenches without damage. Minimum quench energies were found to be in the range of 200-500mJ in background fields of 15-20T when the coil carried 70-95% of its critical quench current
Alkynyl N-Nosylhydrazones: Easy Decomposition to Alknynl Diazomethanes and Application in Allene Synthesis
No full textThe decomposition of N-tosylhydrazones is a safe and convenient method for the generation of donor carbenes. However, alkynyl carbenes cannot be iso- lated by this route because they readily undergo intramo- lecular cyclization to pyrazoles as soon as formed from al- kynyl N-tosylhydrazones. Here, the use of alkynyl N-nosyl- hydrazones for the in situ generation of alkynyl carbenes and their coupling reaction with boronic acids under metal-free conditions is reported, giving rise to a wide array of di- and trisubstituted allenes. Preliminary mecha- nistic investigations demonstrated that g-protodeboration of propargyl boric acid was responsible for the initial allene formation. This methodology based on the nosyl group allows for novel transformations that involve an al- kynylcarbene transient species
Achieving full diversity in multi-antenna two-way relay networks via symbol-based physical-layer network coding
No full textThis paper considers physical-layer network coding (PNC) with M-ary phase-shift keying (MPSK) modulation in two-way relay channel (TWRC). A low complexity detection technique, termed symbol-based PNC (SPNC), is proposed for the relay. In particular, attributing to the outer product operation imposed on the superposed MPSK signals at the relay, SPNC obtains the network-coded symbol (NCS) straightforwardly without having to detect individual symbols separately. Unlike the optimal multi-user detector (MUD) which searches over the combinations of all users’ modulation constellations, SPNC searches over only one modulation constellation, thus simplifies the NCS detection. Despite the reduced complexity, SPNC achieves full diversity in multi-antenna relay as the optimal MUD does. Specifically, antenna selection based SPNC (AS-SPNC) scheme and signal combining based SPNC (SC-SPNC) scheme are proposed. Our analysis of these two schemes not only confirms their full diversity performance, but also implies when SPNC is applied in multi-antenna relay, TWRC can be viewed as an effective single-input multiple-output (SIMO) system, in which AS-PNC and SC-PNC are equivalent to the general AS scheme and the maximal-ratio combining (MRC) scheme. Moreover, an asymptotic analysis of symbol error rate (SER) is provided for SC-PNC considering the case that the number of relay antennas is sufficiently large
Bi-spectrum counter maps under normal condition.
No full textBi-spectrum counter maps under normal condition.</p
Bi-spectrum counter maps under impeller wearing fault condition.
No full textBi-spectrum counter maps under impeller wearing fault condition.</p
The Right Tool in the Right Hands: The Role of Alternative Assets in a Long-term Institutional Portfolio
No full textBI, 201.. Masteroppgave(MSc) in Master of Business - Handelshøyskolen BI, 2018We compare the investment philosophy and management style of the Norwegian
Government Pension Fund Global (GPFG), Canada Pension Plan (CPP), and
Australian Future Fund (FF) with focus on extracting the role of alternative assets
in these portfolios. We decompose fund returns into manager skill (alpha) and
exposure to (1) the market, and other compensated factors, or (2) benchmark
indices. We find that GPFG and FF’s returns are consistent with their stated models.
FF’s results indicate that if deployed effectively, exposure to alternative assets can
improve risk-adjusted performance. However, as we observe for CPP, the illiquid
and opaque nature of alternative assets can also provide scope for managersmoothed
returns, especially in combination with internal investment management.
Overall, our paper proposes that the inclusion of alternative assets in a long-term
institutional portfolio can provide diversification benefits, but we caution that
accurate and timely disclosure of investment performance is critical. The
performance of alternative assets should be assessed with a healthy degree of
scepticism in cases where management and reporting of the assets is performed by
the same group
Optical and electronic properties of bismuth-implanted glasses
No full textPhotoluminescence (PL) and excitation spectra of Bi melt doped oxide and chalcogenide glasses are very similar, indicating the same Bi center is present. When implanted with Bi, chalcogenide, phosphate and silica glass, and BaF2 crystal all display characteristically different PL spectra to when Bi is incorporated by melt-doping. This indicates that ion implantation is able to generate Bi centers which are not present in samples whose dopants are introduced during melting. Bi-related PL bands have been observed in glasses with very similar compositions to those in which carrier-type reversal has been observed, indicating that these phenomena are related to the same Bi centers, which we suggest are interstitial Bi2+ and Bi clusters
Bi-spectrum counter map of valve plate wearing.
No full textBi-spectrum counter map of valve plate wearing.</p
Bi-spectrum counter map of piston shoes and swashplate wearing.
No full textBi-spectrum counter map of piston shoes and swashplate wearing.</p
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