512 research outputs found
Parallel Acceleration and Improvement of Gravitational Field Optimization Algorithm
The Gravitational Field Algorithm, a modern optimization algorithm, mainly simulates celestial mechanics and is derived from the Solar Nebular Disk Model (SNDM). It simulates the process of planetary formation to search for the optimal solution. Although this optimization algorithm has more advantages than other optimization algorithms in multi-peak optimization problems, it still has the shortcoming of long computation time when dealing with large-scale datasets or solving complex problems. Therefore, it is necessary to improve the efficiency of the Gravitational Field Algorithm (GFA). In this paper, an optimization method based on multi-population parallel is proposed to accelerate the Gravitational Field Algorithm. With the help of the parallel mechanism in MATLAB, the algorithm execution speed will be improved by using the parallel computing mode of multi-core CPU. In addition, this paper also improves the absorption operation strategy. By comparing the experimental results of eight classical unconstrained optimization problems, it is shown that the computational efficiency of this method is improved compared with the original Gravitational Field Algorithm, and the algorithm accuracy has also been slightly improved
Morphological and Functional Differences between Athletes and Novices in Cortical Neuronal Networks
Y Chromosomes of 40% Chinese Are Descendants of Three Neolithic Super-grandfathers
Demographic change of human populations is one of the central questions for
delving into the past of human beings. To identify major population expansions
related to male lineages, we sequenced 78 East Asian Y chromosomes at 3.9 Mbp
of the non-recombining region (NRY), discovered >4,000 new SNPs, and identified
many new clades. The relative divergence dates can be estimated much more
precisely using molecular clock. We found that all the Paleolithic divergences
were binary; however, three strong star-like Neolithic expansions at ~6 kya
(thousand years ago) (assuming a constant substitution rate of 1e-9/bp/year)
indicates that ~40% of modern Chinese are patrilineal descendants of only three
super-grandfathers at that time. This observation suggests that the main
patrilineal expansion in China occurred in the Neolithic Era and might be
related to the development of agriculture.Comment: 29 pages of article text including 1 article figure, 9 pages of SI
text, and 2 SI figures. 5 SI tables are in a separate ancillary fil
5,5′-Bis(diethylamino)-2,2′-[butane-1,4-diyldioxybis(nitrilomethylidyne)]diphenol
The title complex, C26H38N4O4, was synthesized by the reaction of 4-diethylamino-2-hydroxybenzaldehyde with 1,4-bis(aminooxy)butane in ethanol. It crystallizes as discrete centrosymmetric molecules adopting an extended conformation where the two salicylaldoxime groups are separated from each other. Intramolecular O—H⋯N hydrogen bonding is observed between the hydroxy groups and oxime N atoms. Intermolecular π–π stacking interactions [3.979 (2) Å] between aromatic rings are apparent in the crystal structure. Each ethyl group is disordered over two positions; in one the site occupancy factors are 0.55 and 0.45, in the other 0.53 and 0.47
Experimental Implementation of Noncyclic and Nonadiabatic Geometric Quantum Gates in a Superconducting Circuit
Quantum gates based on geometric phases possess intrinsic noise-resilience
features and therefore attract much attention. However, the implementations of
previous geometric quantum computation typically require a long pulse time of
gates. As a result, their experimental control inevitably suffers from the
cumulative disturbances of systematic errors due to excessive time consumption.
Here, we experimentally implement a set of noncyclic and nonadiabatic geometric
quantum gates in a superconducting circuit, which greatly shortens the gate
time. And also, we experimentally verify that our universal single-qubit
geometric gates are more robust to both the Rabi frequency error and qubit
frequency shift-induced error, compared to the conventional dynamical gates, by
using the randomized benchmarking method. Moreover, this scheme can be utilized
to construct two-qubit geometric operations, while the generation of the
maximally entangled Bell states is demonstrated. Therefore, our results provide
a promising routine to achieve fast, high-fidelity, and error-resilient quantum
gates in superconducting quantum circuits
Application of Local Wave Decomposition in Seismic Signal Processing
Local wave decomposition (LWD) method plays an important role in seismic signal processing for its superiority in significantly revealing the frequency content of a seismic signal changes with time variation. The LWD method is an effective way to decompose a seismic signal into several individual components. Each component represents a harmonic signal localized in time, with slowly varying amplitudes and frequencies, potentially highlighting different geologic and stratigraphic information. Empirical mode decomposition (EMD), the synchrosqueezing transform (SST), and variational mode decomposition (VMD) are three typical LWD methods. We mainly study the application of the LWD method especially EMD, SST, and VMD in seismic signal processing including seismic signal de‐noising, edge detection of seismic images, and recovery of the target reflection near coal seams
Simultaneous Structural Identification of Natural Products in Fractions of Crude Extract of the Rare Endangered Plant Anoectochilus roxburghii Using 1H NMR/RRLC-MS Parallel Dynamic Spectroscopy
Nuclear magnetic resonance/liquid chromatography-mass spectroscopy parallel dynamic spectroscopy (NMR/LC-MS PDS) is a method aimed at the simultaneous structural identification of natural products in complex mixtures. In this study, the method is illustrated with respect to 1H NMR and rapid resolution liquid chromatography-mass spectroscopy (RRLC-MS) data, acquired from the crude extract of Anoectochilus roxburghii, which was separated into a series of fractions with the concentration of constituent dynamic variation using reversed-phase preparative chromatography. Through fraction ranges and intensity changing profiles in 1H NMR/RRLC–MS PDS spectrum, 1H NMR and the extracted ion chromatogram (XIC) signals deriving from the same individual constituent, were correlated due to the signal amplitude co-variation resulting from the concentration variation of constituents in a series of incompletely separated fractions. 1H NMR/RRLC-MS PDS was then successfully used to identify three types of natural products, including eight flavonoids, four organic acids and p-hydroxybenzaldehyde, five of which have not previously been reported in Anoectochilus roxburghii. In addition, two groups of co-eluted compounds were successfully identified. The results prove that this approach should be of benefit in the unequivocal structural determination of a variety of classes of compounds from extremely complex mixtures, such as herbs and biological samples, which will lead to improved efficiency in the identification of new potential lead compounds
Characterization of Structure and Antioxidant Activity of Polysaccharides From Sesame Seed Hull
Sesame seed hull is the major by-product of sesame seed processing and is rich in polysaccharides. In this work, sesame hull polysaccharides (SHP) were extracted by ultrasound-assisted alkali extraction methods with a yield of 6.49%. Three purified polysaccharide fractions were obtained after decolorization, deproteinization, and column chromatography. Then, their main composition and antioxidant activity were investigated. The dominant fraction was SHP-2 with a yield of 3.78%. It was composed of galacturonic acid (51.3%), glucuronic acid (13.8%), rhamnose (8.9%), glucose (8.4%), and others. The linkage types of SHP-2 have the α-D-GalpA-(1,4)-linked, α-D-GlcpA-(1,2)-linked, β-T-D-Rhap-linked, β-D-Glcp-(1,6)-linked, β-T-D-Galp-linked, α-L-Xylp-(1,4)-linked, α-L-Araf-(1,3,5)-linked, and β-D-Manp-(1,4)-linked. This study might provide some useful basic data for developing applications for sesame seed hull polysaccharides in the food and pharmaceutical industries
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