861 research outputs found
Double Carbon Coated LiCoPO4 Nano Composite as High-Performance Cathode for Lithium Ion Batteries
Polyacene(PAS)/carbon and acetylene black(AB)/carbon coated lithium cobalt phosphate composites were synthesized via the solid state reaction method using co-precipitated Co3(PO4)2·8H2O and Li3PO4 mixture as its precursor. X-ray powder diffraction (XRD) was performed to investigate the structure and phase of all the samples. The transmission electron microscopy (TEM) shows that the double carbon layers coated on the surface of LiCoPO4 successfully. The LiCoPO4/C, LiCoPO4/PAS and LiCoPO4/AB delivered a capacity of T 120.92, 121.07 and 138.06 mAh×g-1 at 0.1C, respectively. The double carbon coated LiCoPO4 electrode delivered an initial discharge capacity of 147.12, 143.51 mAh×g-1 after AB/glucose, PAS/glucose coating, which maintained at 59.5% and 61.7% after 15 cycles at the 0.1C rate, respectively.Citiation: Yu, Y., Zhao, H., Chen, Y., Feng, Z.-k., Liu, X., and Yang, H. (2020). Double Carbon Coated LiCoPO4 Nano Composite as High-Performance Cathode for Lithium Ion Batteries. Trends in Renewable Energy, 6, 1-11. DOI: 10.17737/tre.2020.6.1.0010
Inheriting Bayer's Legacy-Joint Remosaicing and Denoising for Quad Bayer Image Sensor
Pixel binning based Quad sensors have emerged as a promising solution to
overcome the hardware limitations of compact cameras in low-light imaging.
However, binning results in lower spatial resolution and non-Bayer CFA
artifacts. To address these challenges, we propose a dual-head joint
remosaicing and denoising network (DJRD), which enables the conversion of noisy
Quad Bayer and standard noise-free Bayer pattern without any resolution loss.
DJRD includes a newly designed Quad Bayer remosaicing (QB-Re) block, integrated
denoising modules based on Swin-transformer and multi-scale wavelet transform.
The QB-Re block constructs the convolution kernel based on the CFA pattern to
achieve a periodic color distribution in the perceptual field, which is used to
extract exact spectral information and reduce color misalignment. The
integrated Swin-Transformer and multi-scale wavelet transform capture non-local
dependencies, frequency and location information to effectively reduce
practical noise. By identifying challenging patches utilizing Moire and zipper
detection metrics, we enable our model to concentrate on difficult patches
during the post-training phase, which enhances the model's performance in hard
cases. Our proposed model outperforms competing models by approximately 3dB,
without additional complexity in hardware or software
High-Frequency Sea Level Variations Observed by GPS Buoys Using Precise Point Positioning Technique
In this study, sea level variation observed by a 1-Hz Global Positioning System (GPS) buoy system is verified by comparing with tide gauge records and is decomposed to reveal high-frequency signals that cannot be detected from 6-minute tide gauge records. Compared to tide gauges traditionally used to monitor sea level changes and affected by land motion, GPS buoys provide high-frequency geocentric measurements of sea level variations. Data from five GPS buoy campaigns near a tide gauge at Anping, Tainan, Taiwan, were processed using the Precise Point Positioning (PPP) technique with four different satellite orbit products from the International GNSS Service (IGS). The GPS buoy data were also processed by a differential GPS (DGPS) method that needs an additional GPS receiver as a reference station and the accuracy of the solution depends on the baseline length. The computation shows the average Root Mean Square Error (RMSE) difference of the GPS buoy using DGPS and tide gauge records is around 3 - 5 cm. When using the aforementioned IGS orbit products for the buoy derived by PPP, its average RMSE differences are 5 - 8 cm, 8 - 13 cm, decimeter level, and decimeter-meter level, respectively, so the accuracy of the solution derived by PPP highly depends on the accuracy of IGS orbit products. Therefore, the result indicates that the accuracy of a GPS buoy using PPP has the potential to measure the sea surface variations to several cm. Finally, high-frequency sea level signals with periods of a few seconds to a day can be successfully detected in GPS buoy observations using the Ensemble Empirical Mode Decomposition (EMD) method and are identified as waves, meteotsunamis, and tides
Aerobic Anoxygenic Phototrophic Bacteria Promote the Development of Biological Soil Crusts
Chlorophyll-containing oxygenic photoautotrophs have been well known to play a fundamental role in the development of biological soil crusts (BSCs) by harvesting solar radiations and providing fixed carbon to the BSCs ecosystems. Although the same functions can be theoretically fulfilled by the widespread bacteriochlorophyll-harboring aerobic anoxygenic phototrophic bacteria (AAnPB), whether AAnPB play a role in the formation of BSCs and how important they are to this process remain largely unknown. To address these questions, we set up a microcosm system with surface sands of the Hopq desert in northern China and observed the significant effects of near-infrared illumination on the development of BSCs. Compared to near-infrared or red light alone, the combined use of near-infrared and red lights for illumination greatly increased the thickness of BSCs, their organic matter contents and the microalgae abundance by 24.0, 103.7, and 1447.6%, respectively. These changes were attributed to the increasing abundance of AAnPB that can absorb near-infrared radiations. Our data suggest that AAnPB is a long-overlooked driver in promoting the development of BSCs in drylands
MicroRec: Efficient Recommendation Inference by Hardware and Data Structure Solutions
Deep neural networks are widely used in personalized recommendation systems.
Unlike regular DNN inference workloads, recommendation inference is
memory-bound due to the many random memory accesses needed to lookup the
embedding tables. The inference is also heavily constrained in terms of latency
because producing a recommendation for a user must be done in about tens of
milliseconds. In this paper, we propose MicroRec, a high-performance inference
engine for recommendation systems. MicroRec accelerates recommendation
inference by (1) redesigning the data structures involved in the embeddings to
reduce the number of lookups needed and (2) taking advantage of the
availability of High-Bandwidth Memory (HBM) in FPGA accelerators to tackle the
latency by enabling parallel lookups. We have implemented the resulting design
on an FPGA board including the embedding lookup step as well as the complete
inference process. Compared to the optimized CPU baseline (16 vCPU,
AVX2-enabled), MicroRec achieves 13.8~14.7x speedup on embedding lookup alone
and 2.5$~5.4x speedup for the entire recommendation inference in terms of
throughput. As for latency, CPU-based engines needs milliseconds for inferring
a recommendation while MicroRec only takes microseconds, a significant
advantage in real-time recommendation systems.Comment: Accepted by MLSys'21 (the 4th Conference on Machine Learning and
Systems
Prevalence and prognosis of molecularly defined familial hypercholesterolemia in patients with acute coronary syndrome
BackgroundFamilial hypercholesterolemia (FH) can elevate serum low-density lipoprotein cholesterol (LDL-C) levels, which can promote the progression of acute coronary syndrome (ACS). However, the effect of FH on the prognosis of ACS remains unclear.MethodsIn this prospective cohort study, 223 patients with ACS having LDL-C ≥ 135.3 mg/dL (3.5 mmol/L) were enrolled and screened for FH using a multiple-gene FH panel. The diagnosis of FH was defined according to the ACMG/AMP criteria as carrying pathogenic or likely pathogenic variants. The clinical features of FH and the relationship of FH to the average 16.6-month risk of cardiovascular events (CVEs) were assessed.ResultsThe prevalence of molecularly defined FH in enrolled patients was 26.9%, and coronary artery lesions were more severe in patients with FH than in those without (Gensini score 66.0 vs. 28.0, respectively; P < 0.001). After lipid lowering, patients with FH still had significantly higher LDL-C levels at their last visit (73.5 ± 25.9 mg/dL vs. 84.7 ± 37.1 mg/dL; P = 0.013) compared with those without. FH increased the incidence of CVEs in patients with ACS [hazard ratio (HR): 3.058; 95% confidence interval (CI): 1.585–5.900; log-rank P < 0.001].ConclusionFH is associated with an increased risk of CVEs in ACS and is an independent risk factor for ACS. This study highlights the importance of genetic testing of FH-related gene mutations in patients with ACS
Polyethylene Glycol Electrolyte Lavage Solution versus Colonic Hydrotherapy for Bowel Preparation before Colonoscopy: A Single Center, Randomized, and Controlled Study
This single center, randomized, and controlled study aimed to compare the effectiveness and safety of polyethylene glycol electrolyte lavage (PEG-EL) solution and colonic hydrotherapy (CHT) for bowel preparation before colonoscopy. A total of 196 eligible outpatients scheduled for diagnostic colonoscopy were randomly assigned to the PEG-EL (n=102) or CHT (n=94) groups. Primary outcome measures included colonic cleanliness and adverse effects. Secondary outcome measures were patient satisfaction and preference, colonoscopic findings, ileocecal arrival rate, examiner satisfaction, and cecal intubation time. The results show that PEG-EL group was associated with significantly better colonic cleanliness than CHT group, fewer adverse effects, and increased examiner satisfaction. However, the CHT group had higher patient satisfaction and higher diverticulosis detection rates. Moreover, the results showed the same ileocecal arrival rate and patient preference between the two groups (P>0.05). These findings indicate that PEG-EL is the preferred option in patients who followed the preparation instructions completely
An Updated Search of Steady TeV Ray Point Sources in Northern Hemisphere Using the Tibet Air Shower Array
Using the data taken from Tibet II High Density (HD) Array (1997
February-1999 September) and Tibet-III array (1999 November-2005 November), our
previous northern sky survey for TeV ray point sources has now been
updated by a factor of 2.8 improved statistics. From to
in declination (Dec) range, no new TeV ray point
sources with sufficiently high significance were identified while the
well-known Crab Nebula and Mrk421 remain to be the brightest TeV ray
sources within the field of view of the Tibet air shower array. Based on the
currently available data and at the 90% confidence level (C.L.), the flux upper
limits for different power law index assumption are re-derived, which are
approximately improved by 1.7 times as compared with our previous reported
limits.Comment: This paper has been accepted by hepn
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