High Speed Mid-Wave Infrared Uni-traveling Carrier Photodetector

Mid-wave infrared (MWIR) frequency comb is expected to dramatically improve the precision and sensitivity of molecular spectroscopy. For high resolution application, high speed MWIR photodetector is one of the key components, however, the commercially available high speed MWIR photodetector only has sub-GHz bandwidth currently. In this paper, we demonstrate, for the first time to our knowledge, a high speed mid-wave infrared (MWIR) uni-traveling carrier photodetector based on InAs/GaSb type-II superlattice (T2SL) at room temperature. The device exhibits a cutoff wavelength of 5.6{\mu}m, and 3dB bandwidth of 6.58 GHz for a 20{\mu}m diameter device at 300K. These promising results show the device has potential to be utilized in high speed applications such as frequency comb spectroscopy, free space communication and others. The limitations on the high frequency performance of the photodetectors are also discussed

Passive detection of moving aerial target based on multiple collaborative GPS satellites

Passive localization is an important part of intelligent surveillance in security and emergency applications. Nowadays, Global Navigation Satellite Systems (GNSSs) have been widely deployed. As a result, the satellite signal receiver may receive multiple GPS signals simultaneously, incurring echo signal detection failure. Therefore, in this paper, a passive method leveraging signals from multiple GPS satellites is proposed for moving aerial target detection. In passive detection, the first challenge is the interference caused by multiple GPS signals transmitted upon the same spectrum resources. To address this issue, successive interference cancellation (SIC) is utilized to separate and reconstruct multiple GPS signals on the reference channel. Moreover, on the monitoring channel, direct wave and multi-path interference are eliminated by extensive cancellation algorithm (ECA). After interference from multiple GPS signals is suppressed, the cycle cross ambiguity function (CCAF) of the signal on the monitoring channel is calculated and coordinate transformation method is adopted to map multiple groups of different time delay-Doppler spectrum into the distance−velocity spectrum. The detection statistics are calculated by the superposition of multiple groups of distance-velocity spectrum. Finally, the echo signal is detected based on a properly defined adaptive detection threshold. Simulation results demonstrate the effectiveness of our proposed method. They show that the detection probability of our proposed method can reach 99%, when the echo signal signal-to-noise ratio (SNR) is only −64 dB. Moreover, our proposed method can achieve 5 dB improvement over the detection method using a single GPS satellite

Effects of icariin and quercetin on high glucose-induced neuronal cell apoptosis

Purpose: To study the effects of icariin and quercetin on cell apoptotic changes in neurons induced by elevated glucose condition, and the  mechanism involved. Methods: Neonatal male Sprague Dawley rats (n = 48) weighing 5 – 7 g were used. Neuronal cells were isolated from rat hippocampus and cultured after purification. The cells were randomly assigned to six groups: control, high glucose, icariin, quercetin, serine/threonine-specific protein kinase (Akt) inhibitor, and Akt agonist groups. The Akt inhibitor and agonist used in this study were MK-22062hci and SC79, respectively. The influence of icariin and quercetin on neuronal apoptotic changes were determined flow cytometrically, while their effects on levels of expression of Akt, p-Akt, bax and bcl-2 were determined with Western blotting. Results: Treatment with icariin or quercetin significantly inhibited apoptosis induced by high glucose. The concentrations of Akt, p-Akt, and bcl-2 proteins were markedly upregulated in high glucose group, relative to control (p < 0.05). The corresponding expression of bax was significantly down-regulated in high glucose group, relative to control (p < 0.05). Treatment with icariin or quercetin, or their agonists reversed high glucose-mediated alterations in these protein levels (p < 0.05). Conclusion: Icariin and quercetin inhibit neuronal cell apoptosis induced by high glucose through upregulation of bcl-2 expression and down- regulations of bax expression and Akt-induced protein phosphorylation. Thus, Icariin and quercetin possess potential benefits for the treatment of neurological diseases. Keywords: Apoptosis, High glucose condition, Hippocampal neurons, Icariin, Querceti

Fluorescent sensing of mercury(II) based on formation of catalytic gold nanoparticles

A fluorescence assay for the highly sensitive and selective detection of Hg2+ using a gold nanoparticle (AuNP)-based probewas proposed. The assay was based on the formation of Hg-Au alloys, which accelerated the oxidization of o-phenylenediamine by dissolved oxygen to produce 2,3-diaminophenazine, a fluorescent product.;A fluorescence assay for the highly sensitive and selective detection of Hg2+ using a gold nanoparticle (AuNP)-based probewas proposed. The assay was based on the formation of Hg-Au alloys, which accelerated the oxidization of o-phenylenediamine by dissolved oxygen to produce 2,3-diaminophenazine, a fluorescent product

C⋅\cdotASE: Learning Conditional Adversarial Skill Embeddings for Physics-based Characters

We present C$\cdot$ASE, an efficient and effective framework that learns conditional Adversarial Skill Embeddings for physics-based characters. Our physically simulated character can learn a diverse repertoire of skills while providing controllability in the form of direct manipulation of the skills to be performed. C$\cdot$ASE divides the heterogeneous skill motions into distinct subsets containing homogeneous samples for training a low-level conditional model to learn conditional behavior distribution. The skill-conditioned imitation learning naturally offers explicit control over the character's skills after training. The training course incorporates the focal skill sampling, skeletal residual forces, and element-wise feature masking to balance diverse skills of varying complexities, mitigate dynamics mismatch to master agile motions and capture more general behavior characteristics, respectively. Once trained, the conditional model can produce highly diverse and realistic skills, outperforming state-of-the-art models, and can be repurposed in various downstream tasks. In particular, the explicit skill control handle allows a high-level policy or user to direct the character with desired skill specifications, which we demonstrate is advantageous for interactive character animation.Comment: SIGGRAPH Asia 202

Strategic ambidexterity and innovation in Chinese multinational vs. indIgenous firms : The role of managerial capability

The authors would like to acknowledge the financial support provided by National Natural Science Foundation of China (No. 71728003) and University of Macau MYRG (Grant Number: 2016-00207-FBA, Grant Number: 2018-00171-FBA) for this research.Peer reviewedPostprin

Joint Fronthaul Load Balancing and Computation Resource Allocation in Cell-Free User-Centric Massive MIMO Networks

We consider scalable cell-free massive multiple-input multiple-output networks under an open radio access network paradigm comprising user equipments (UEs), radio units (RUs), and decentralized processing units (DUs). UEs are served by dynamically allocated user-centric clusters of RUs. The corresponding cluster processors (implementing the physical layer for each user) are hosted by the DUs as software-defined virtual network functions. Unlike the current literature, mainly focused on the characterization of the user rates under unrestricted fronthaul communication and computation, in this work we explicitly take into account the fronthaul topology, the limited fronthaul communication capacity, and computation constraints at the DUs. In particular, we systematically address the new problem of joint fronthaul load balancing and allocation of the computation resource. As a consequence of our new optimization framework, we present representative numerical results highlighting the existence of an optimal number of quantization bits in the analog-to-digital conversion at the RUs.Comment: 13 pages, 5 figures, submitted to IEEE Transactions on Wireless Communication