Weighted incoherent signal subspace method for DOA estimation on wideband colored signals

Wideband direction-of-arrival (DOA) estimation is a key part in array signal processing. Existing algorithms for the wideband DOA estimation are often studied in the situation of uniformly distributed energy. And all the frequency bins are weighted equally in these algorithms. However, these algorithms perform unsatisfactorily when encountering wideband colored signals with nonuniform energy spectrum. To improve the performance of DOA estimation for wideband colored signals, we proposed two weighting methods, which are based on the perturbed subspace theory and random matrix theory respectively. The two methods weight the space spectrum from all the frequency bins according to the mean square error (MSE) of DOA estimation in each frequency bin. Numerical results show that the random matrix theory based method performs well, due to the inference premise that the dimensions of matricesincrease at the same rate. The perturbed subspace based method, which is concise in calculating the weights, shows high accuracy only at high signal to noise ratio (SNR) and with adequate snapshots. The effectiveness of the two algorithms are also demonstrated by comparing them to various existing algorithms and the Cramér-Rao bound

Rapid and controllable synthesis of nanocrystallized nickel-cobalt boride electrode materials via a mircoimpinging stream reaction for high performance supercapacitors

Nickel-cobalt borides (denoted as NCBs) have been considered as a promising candidate for aqueous supercapacitors due to their high capacitive performances. However, most reported NCBs are amorphous that results in slow electron transfer and even structure collapse during cycling. In this work, a nanocrystallized NCBs-based supercapacitor is successfully designed via a facile and practical microimpinging stream reactor (MISR) technique, composed of a nanocrystallized NCB core to facilitate the charge transfer, and a tightly contacted Ni-Co borates/metaborates (NCBi) shell which is helpful for OH^- adsorption. These merits endow NCB@NCBi a large specific capacity of 966 C g^-1 (capacitance of 2415 F g^-1) at 1 A g^-1 and good rate capability (633.2 C g^-1 at 30 A g^-1), as well as a very high energy density of 74.3 Wh kg^-1 in an asymmetric supercapacitor device. More interestingly, it is found that a gradual in situ conversion of core NCBs to nanocrystallized Ni-Co (oxy)-hydroxides inwardly takes place during the cycles, which continuously offers large specific capacity due to more electron transfer in the redox reaction processes. Meanwhile, the electron deficient state of boron in metal-borates shells can make it easier to accept electrons and thus promote ionic conduction

Persisting RB-tree into NVM in a consistency perspective

Byte-addressable non-volatile memory (NVM) is going to reshape conventional computer systems. With advantages of low latency, byte-addressability, and non-volatility, NVM can be directly put on the memory bus to replace DRAM. As a result, both system and application softwares have to be adjusted to perceive the fact that the persistent layer moves up to the memory. However, most of the current in-memory data structures will be problematic with consistency issues if not well tuned with NVM. This article places emphasis on an important in-memory structure that is widely used in computer systems, i.e., the Red/Black-tree (RB-tree). Since it has a long and complicated update process, the RB-tree is prone to inconsistency problems with NVM. This article presents an NVM-compatible consistent RB-tree with a new technique named cascade-versioning. The proposed RB-tree (i) is all-time consistent and scalable and (ii) needs no recovery procedure after system crashes. Experiment results show that the RB-tree for NVM not only achieves the aim of consistency with insignificant spatial overhead but also yields comparable performance to an ordinary volatile RB-tree

Orbital Angular Momentum Multiplexing in Space-Time Thermoacoustic Metasurfaces

Multiplexing technology with increased information capacity plays a crucial role in the realm of acoustic communication. Different quantities of sound waves, including time, frequency, amplitude, phase, and orbital angular momentum (OAM), have been independently introduced as the physical multiplexing approach to allow for enhanced communication densities. An acoustic metasurface is decorated with carbon nanotube patches, which when electrically pumped and set to rotate, functions as a hybrid mode-frequency-division multiplexer with synthetic dimensions. Based on this spatiotemporal modulation, a superposition of vortex beams with orthogonal OAMs and symmetric harmonics are both numerically and experimentally demonstrated. Also, flexible combinations of OAM modes with diverse frequency shifts are obtained by transforming the azimuthal phase distributions, which inspires a mode-frequency-division multiplexing approach that significantly promotes the communication capacity.This work was supported by National Basic Research Program of China (2017YFA0303702), NSFC (12074183, 11922407, 11834008, and 11874215), and the Fundamental Research Funds for the Central Universities (020414380181). J.C. acknowledges support from the European Research Council (ERC) through the Starting Grant 714577 PHONOMETA

Rapid and Controllable Synthesis of Nanocrystallized Nickel‐Cobalt Boride Electrode Materials via a Mircoimpinging Stream Reaction for High Performance Supercapacitors

Nickel-cobalt borides (denoted as NCBs) have been considered as a promising candidate for aqueous supercapacitors due to their high capacitive performances. However, most reported NCBs are amorphous that results in slow electron transfer and even structure collapse during cycling. In this work, a nanocrystallized NCBs-based supercapacitor is successfully designed via a facile and practical microimpinging stream reactor (MISR) technique, composed of a nanocrystallized NCB core to facilitate the charge transfer, and a tightly contacted Ni-Co borates/metaborates (NCBi) shell which is helpful for OH^- adsorption. These merits endow NCB@NCBi a large specific capacity of 966 C g^-1 (capacitance of 2415 F g^-1) at 1 A g^-1 and good rate capability (633.2 C g^-1 at 30 A g^-1), as well as a very high energy density of 74.3 Wh kg^-1 in an asymmetric supercapacitor device. More interestingly, it is found that a gradual in situ conversion of core NCBs to nanocrystallized Ni-Co (oxy)-hydroxides inwardly takes place during the cycles, which continuously offers large specific capacity due to more electron transfer in the redox reaction processes. Meanwhile, the electron deficient state of boron in metal-borates shells can make it easier to accept electrons and thus promote ionic conduction

SCARB2 drives hepatocellular carcinoma tumor initiating cells via enhanced MYC transcriptional activity

Abstract CSCs (Cancer stem cells) with distinct metabolic features are considered to cause HCC (hepatocellular carcinoma) initiation, metastasis and therapeutic resistance. Here, we perform a metabolic gene CRISPR/Cas9 knockout library screen in tumorspheres derived from HCC cells and find that deletion of SCARB2 suppresses the cancer stem cell-like properties of HCC cells. Knockout of Scarb2 in hepatocytes attenuates HCC initiation and progression in both MYC-driven and DEN (diethylnitrosamine)-induced HCC mouse models. Mechanistically, binding of SCARB2 with MYC promotes MYC acetylation by interfering with HDCA3-mediated MYC deacetylation on lysine 148 and subsequently enhances MYC transcriptional activity. Screening of a database of FDA (Food and Drug Administration)-approved drugs shows Polymyxin B displays high binding affinity for SCARB2 protein, disrupts the SCARB2-MYC interaction, decreases MYC activity, and reduces the tumor burden. Our study identifies SCARB2 as a functional driver of HCC and suggests Polymyxin B-based treatment as a targeted therapeutic option for HCC