For dual‐channel time‐frequency (TF) overlapped signals with low sparsity in underdetermined blind source separation (UBSS), this paper proposes an effective method based on interval probability to ...estimate and expand the types of mixing matrices. First, the detection of TF single‐source points (TF‐SSP) is used to improve the TF sparsity of each source. For more distinguishability, as the ratios of the coefficients from different columns of the mixing matrix are close, a local peak‐detection mechanism based on interval probability (LPIP) is proposed. LPIP utilizes uniform subintervals to optimize and classify the TF coefficient ratios of the detected TF‐SSP effectively in the case of a high level of TF overlap among sources and reduces the TF interference points and redundant signal features greatly to enhance the estimation accuracy. The simulation results show that under both noiseless and noisy cases, the proposed method performs better than the selected mainstream traditional methods, has good robustness, and has low algorithm complexity.
For dual-channel time-frequency (TF) overlapped signals with low sparsity in underdetermined blind source separation (UBSS), this paper proposes an effective method based on interval probability to ...estimate and expand the types of mixing matrices. First, the detection of TF single-source points (TF-SSP) is used to improve the TF sparsity of each source. For more distinguishability, as the ratios of the coefficients from different columns of the mixing matrix are close, a local peak-detection mechanism based on interval probability (LPIP) is proposed. LPIP utilizes uniform subintervals to optimize and classify the TF coefficient ratios of the detected TF-SSP effectively in the case of a high level of TF overlap among sources and reduces the TF interference points and redundant signal features greatly to enhance the estimation accuracy. The simulation results show that under both noiseless and noisy cases, the proposed method performs better than the selected mainstream traditional methods, has good robustness, and has low algorithm complexity.
•Magnetic properties of Fe-Si composites were improved by addition of CIP powder.•Influence of CIP on properties was discussed according to density and resistivity.•Loss can be reduced by regulation ...of composition and microstructure of SMCs.
FeSi/CIP soft magnetic composites are prepared by cold pressing the mixture of FeSi powders and different content of carbonyl iron powders (CIP), the influence of CIP content on the microstructure, relative density, magnetic properties and the core loss of the composite magnetic powder cores has been investigated and discussed. Appropriate addition of CIP powders can improve relative density of the magnetic powder cores and reduce the effective demagnetizing field, increases the effective permeability and reduces the core loss of the soft magnetic composites. By optimizing the CIP content and preparation process parameters, the composites with 25 wt% CIP compacted at 1200 MPa and heat treated at 500℃ has the optimum comprehensive soft magnetic properties, it shows the permeability of 69, saturation magnetization of 202 emu/g, the DC bias performance improved reaches to 60% at 100 Oe and low core loss of 10.9 W/kg (20 mT, 100 kHz), respectively. The current loss can be reduced by the design and regulation of composition and microstructure of the soft magnetic composites.
A novel positive single-stranded RNA virus, Pleurotus ostreatus deltaflexivirus 1 (PoDFV1), was isolated from the edible fungus
Pleurotus ostreatus
strain ZP6. The complete genome of PoDFV1 is 7706 ...nucleotides (nt) long and contains a short poly(A) tail. PoDFV1 was predicted to contain one large open reading frame (ORF1) and three small downstream ORFs (ORFs 2-4). ORF1 encodes a putative replication-associated polyprotein of 1979 amino acids (aa) containing three conserved domains – viral RNA methyltransferase (Mtr), viral RNA helicase (Hel), and RNA-dependent RNA polymerase (RdRp) – which are common to all deltaflexiviruses. ORFs 2-4 encode three small hypothetical proteins (15-20 kDa) without conserved domains or known biological functions. Sequence alignments and phylogenetic analysis suggested that PoDFV1 is a member of a new species in the genus
Deltaflexivirus
(family
Deltaflexiviridae
, order
Tymovirales
). To our knowledge, this is the first report of a deltaflexivirus infecting
P. ostreatus
.
This paper introduces a new approach for optimization controlling the traffic at an unsignalized cooperative intersection under the Cooperative Vehicle Infrastructure System (CVIS) environment. An ...unsignalized cooperative optimization control method is proposed for effective intersection operations and management based on vehicle speed guidance and information interaction. For the features of information interaction in CVIS, the proposed method that does not require a traffic signal controller at the intersection; instead vehicle speed guidance and "right of way" information optimized by the method will be show on the DMI of On-Board Unit (OBU). Paper developed an unsignalized cooperative optimization control simulation platform based on the Q-Paramics. Experimental results show that compared with traditional actuated control method, the proposed method can effectively reduce the intersection average delay, number of stops and length of queue.
Organic-inorganic hybrid perovskite solar cells have been developing rapidly in the past several years, and their power conversion efficiency has reached over 20%, nearing that of polycrystalline ...silicon solar cells. Because the diffusion length of the hole in perovskites is longer than that of the electron, the performance of the device can be improved by using an electron transporting layer,
e.g.
, TiO
2
, ZnO and TiO
2
/Al
2
O
3
. Nano-structured electron transporting materials facilitate not only electron collection but also morphology control of the perovskites. The properties, morphology and preparation methods of perovskites are reviewed in the present article. A comprehensive understanding of the relationship between the structure and property will benefit the precise control of the electron transporting process and thus further improve the performance of perovskite solar cells.
The properties, morphology and preparation methods of nano-structured electron transporting materials for perovskite solar cells are reviewed in this article.
Organic–inorganic hybrid perovskite solar cells (PSCs) have seen a rapid rise in power conversion efficiencies in recent years; however, they still suffer from interfacial recombination and charge ...extraction losses at interfaces between the perovskite absorber and the charge–transport layers. Here, in situ back‐contact passivation (BCP) that reduces interfacial and extraction losses between the perovskite absorber and the hole transport layer (HTL) is reported. A thin layer of nondoped semiconducting polymer at the perovskite/HTL interface is introduced and it is shown that the use of the semiconductor polymer permits—in contrast with previously studied insulator‐based passivants—the use of a relatively thick passivating layer. It is shown that a flat‐band alignment between the perovskite and polymer passivation layers achieves a high photovoltage and fill factor: the resultant BCP enables a photovoltage of 1.15 V and a fill factor of 83% in 1.53 eV bandgap PSCs, leading to an efficiency of 21.6% in planar solar cells.
An in situ back‐contact passivation strategy is adopted to optimize the photovoltaic performance of n–i–p planar perovskite solar cells. Devices with a flat‐band alignment between the perovskite and polymer passivation layer achieve a high photovoltage of 1.15 V and fill factor of 83% with 1.53 eV bandgap perovskite, leading to a stabilized power conversion efficiency of 21.6%.
Positron emission tomography (PET) imaging plays an indispensable role in early disease detection and postoperative patient staging diagnosis. However, PET imaging requires not only additional ...computed tomography (CT) imaging to provide detailed anatomical information but also attenuation correction (AC) maps calculated from CT images for precise PET quantification, which inevitably demands that patients undergo additional doses of ionizing radiation. To reduce the radiation dose and simultaneously obtain high-quality PET/CT images, in this work, we present an alternative based on deep learning that can estimate synthetic attenuation corrected PET (sAC PET) and synthetic CT (sCT) images from non-attenuation corrected PET (NAC PET) scans for whole-body PET/CT imaging. Our model consists of two stages: the first stage removes noise and artefacts in the NAC PET images to generate sAC PET images, and the second stage synthesizes CT images from the sAC PET images obtained in the first stage. Both stages employ the same deep Wasserstein generative adversarial network and identical loss functions, which encourage the proposed model to generate more realistic and satisfying output images. To evaluate the performance of the proposed algorithm, we conducted a comprehensive study on a total of 45 sets of paired PET/CT images of clinical patients. The final experimental results demonstrated that both the generated sAC PET and sCT images showed great similarity to true AC PET and true CT images based on both qualitative and quantitative analyses. These results also indicate that in the future, our proposed algorithm has tremendous potential for reducing the need for additional anatomic imaging in hybrid PET/CT systems or the need for lengthy MR sequence acquisition in hybrid PET/MRI systems.
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