2,652 research outputs found
Spin-phonon coupling in single Mn doped CdTe quantum dot
The spin dynamics of a single Mn atom in a laser driven CdTe quantum dot is
addressed theoretically. Recent experimental
results\cite{Le-Gall_PRL_2009,Goryca_PRL_2009,Le-Gall_PRB_2010}show that it is
possible to induce Mn spin polarization by means of circularly polarized
optical pumping. Pumping is made possible by the faster Mn spin relaxation in
the presence of the exciton. Here we discuss different Mn spin relaxation
mechanisms. First, Mn-phonon coupling, which is enhanced in the presence of the
exciton. Second, phonon-induced hole spin relaxation combined with carrier-Mn
spin flip coupling and photon emission results in Mn spin relaxation. We model
the Mn spin dynamics under the influence of a pumping laser that injects
excitons into the dot, taking into account exciton-Mn exchange and phonon
induced spin relaxation of both Mn and holes. Our simulations account for the
optically induced Mn spin pumping.Comment: 17 pages, 11 figures, submitted to PR
The prevalence of insomnia in the general population in China: A meta-analysis
This is the first meta-analysis of the pooled prevalence of insomnia in the general population of China. A systematic literature search was conducted via the following databases: PubMed, PsycINFO, EMBASE and Chinese databases (China National Knowledge Interne (CNKI), WanFang Data and SinoMed). Statistical analyses were performed using the Comprehensive Meta-Analysis program. A total of 17 studies with 115,988 participants met the inclusion criteria for the analysis. The pooled prevalence of insomnia in China was 15.0% (95% Confidence interval [CI]: 12.1%-18.5%). No significant difference was found in the prevalence between genders or across time period. The pooled prevalence of insomnia in population with a mean age of 43.7 years and older (11.6%; 95% CI: 7.5%-17.6%) was significantly lower than in those with a mean age younger than 43.7 years (20.4%; 95% CI: 14.2%-28.2%). The prevalence of insomnia was significantly affected by the type of assessment tools (Q = 14.1, P = 0.001). The general population prevalence of insomnia in China is lower than those reported in Western countries but similar to those in Asian countries. Younger Chinese adults appear to suffer from more insomnia than older adults
A Coherent Through-Wall MIMO Phased Array Imaging Radar based on Time-Duplexed Switching
Through-the-Wall (TW) radar sensors are gaining increasing interest for security, surveillance and search and rescue applications. Additionally, the integration of Multiple-Input, Multiple-Output (MIMO) techniques with phased array radar is allowing higher performance at lower cost. In this paper we present a 4-by-4 TW MIMO phased array imaging radar operating at 2.4 GHz with 200 MHz bandwidth. To achieve high imaging resolution in a cost-effective manner, the 4 Tx and 4 Rx elements are used to synthesize a uniform linear array (ULA) of 16 virtual elements. Furthermore, the transmitter is based on a single-channel 4-element time-multiplexed switched array. In transmission, the radar utilizes frequency modulated continuous wave (FMCW) waveforms that undergo de-ramping on receive to allow digitization at relatively low sampling rates, which then simplifies the imaging process. This architecture has been designed for the short-range TW scenarios envisaged, and permits sufficient time to switch between antenna elements. The paper first outlines the system characteristics before describing the key signal processing and imaging algorithms which are based on traditional Fast Fourier Transform (FFT) processing. These techniques are implemented in LabVIEW software. Finally, we report results from an experimental campaign that investigated the imaging capabilities of the system and demonstrated the detection of personnel targets. Moreover, we show that multiple targets within a room with greater than approximately 1 meter separation can be distinguished from one another
Kongish Daily: researching translanguaging creativity and subversiveness
This paper analyses Kongish Daily, a Facebook page that trans-scripts local news in Hong Kong into a creative and dynamic mix of Cantonese in traditional Chinese characters, Romanisation and made-up characters, simplified Chinese, pinyin, English, Hong Kong English, other phonetic symbols, emoji and other signs and images. We trace the origin of the site and rationale for the Facebook page, and analyse it as a translanguaging phenomenon. The main objective is to understand the political motivations for the Facebook account and the social critique it offers through its dynamic translanguaging practice. In particular, we want to highlight the subversive nature of the translanguaging practice. Methodologically, it develops the participatory linguistics framework, which transformed our own understandings of the phenomenon as well as the cultural politics of translingualism and social media in Hong Kong
A new mechanism for exchange processes observed in the compounds [M(η-C_5H_5)_2(exo-η-RCH = CH_2)H], M = Nb and Ta
Dynamic n.m.r. studies of the exchange processes in the complexes [M(η-C_5H_5)(exo-η-RCH=CH_2)H], M = Nb, Ta, lead to the proposal of a new mechanism involving intermediates with agostic bonding
Employment and Career Prospects of Technical-Oriented Jobs in the FinTech Market
FinTech refers to a set of new technologies employed to improve and automate the delivery and use of financial services. This study aims to provide some insightful information to: (a) universities on how to offer their FinTech education, and (b) graduates so that they can make an informed decision on whether they should start their FinTech career journey. To achieve these aims, we explore the credentials of recent and long-time graduates who are working in the FinTech area by conducting a questionnaire survey involving 48 Australian FinTech companies and 83 FinTech practitioners working in various IT functions of these companies. Among the various findings reported in this paper, some of them are: (a) the most straightforward way to start the “technical-oriented” FinTech career is to earn an undergraduate IT degree, (b) possessing previous IT work experience is almost a norm for FinTech practitioners, and (c) for those FinTech practitioners with previous work experience in financial services, they may have a higher chance to be promoted to executives
World-wide epidemiology of HBeAg-negative chronic hepatitis B and associated precore and core promoter variants
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72281/1/j.1365-2893.2002.00304.x.pd
Exciton condensate at a total filling factor of 1 in Corbino 2D electron bilayers
Magneto-transport and drag measurements on a quasi-Corbino 2D electron
bilayer at the systems total filling factor 1 (v_tot=1) reveal a drag voltage
that is equal in magnitude to the drive voltage as soon as the two layers begin
to form the expected v_tot=1 exciton condensate. The identity of both voltages
remains present even at elevated temperatures of 0.25 K. The conductance in the
current carrying layer vanishes only in the limit of strong coupling between
the two layers and at T->0 K which suggests the presence of an excitonic
circular current
Society Leadership and Diversity: Hail to the Women!
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138279/1/hep29392.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138279/2/hep29392_am.pd
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