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

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

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

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

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

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

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

Reply

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142921/1/hep29806_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142921/2/hep29806.pd