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In this letter, we apply a time and frequency analysis method based on the complete ensemble empirical mode decomposition (CEEMD) method in ground-penetrating radar (GPR) signal processing. It decomposes the GPR signal into a sum of oscillatory components, with guaranteed positive and smoothly varying instantaneous frequencies. The key idea of this method relies on averaging the modes obtained by empirical mode decomposition (EMD) applied to several realizations of Gaussian white noise added to the original signal. It can solve the mode-mixing problem in the EMD method and improve the resolution of ensemble EMD (EEMD) when the signal has a low signal-to-noise ratio. First, we analyze the difference between the basic theory of EMD, EEMD, and CEEMD. Then, we compare the time and frequency analysis with Hilbert–Huang transform to test the results of different methods. The synthetic and real GPR data demonstrate that CEEMD promises higher spectral–spatial resolution than the other two EMD methods in GPR signal denoising and target extraction. Its decomposition is complete, with a numerically negligible error.

Summary of genetic statistics for 12 SSR loci in the 36 genotypes analyzed. (DOC 44â kb)

Percentage of homozygous loci in the 36 genotypes analyzed. (DOC 38â kb)

Detailed information of 18 walnut genotypes with short juvenile period and 18 walnut genotypes with long juvenile period. (DOC 42â kb)

The most promising cathode materials, including LiCoO2 (layered), LiMn2 O4 (spinel), and LiFePO4 (olivine), have been the focus of intense research to develop rechargeable lithium-ion batteries (LIBs) for portable electronic devices. Sluggish lithium diffusion, however, and unsatisfactory long-term cycling performance still limit the development of present LIBs for several applications, such as plug-in/hybrid electric vehicles. Motivated by the success of graphene and novel 2D materials with unique physical and chemical properties, herein, a simple shear-assisted mechanical exfoliation method to synthesize few-layered nanosheets of LiCoO2 , LiMn2 O4 , and LiFePO4 is used. Importantly, these as-prepared nanosheets with preferred orientations and optimized stable structures exhibit excellent C-rate capability and long-term cycling performance with much reduced volume expansion during cycling. In particular, the zero-strain insertion phenomenon could be achieved in 2-3 such layers of LiCoO2 electrode materials, which could open up a new way to the further development of next-generation long-life and high-rate batteries.

Walnut (Juglans regia L.) is an economically important tree widely cultivated in temperate regions for its nuts and timber. In this study, molecular identification using 12 simple sequence repeat (SSR) markers and 22 nut-shape characters were conducted on 35 cultivars of walnut grown in China. All 35 cultivars were classified into 11 broad categories on the basis of the nut phenotype. The shape characteristic of longitudinal sections to the suture presented a broad elliptic or elliptic shape was the largest category and included 18 cultivars. All accessions in each category were differentiated by no more than two SSR primer pairs. In addition to nut phenotype, 35 cultivars could be identified using four primer pairs, and every cultivar presented unique fingerprints. In particular, cultivars with the same parents were easily differentiated, such as ‘Liaoning 1’ and ‘Liaoning 3’ based on their different nut shape. Regardless of nut phenotype characters, just four loci (WJR031, WJR069, WJR265, and WJR281) also allowed the unambiguous separation of the 35 cultivars studied. This study provides a useful protocol for the characterization, identification, and authentication of any walnut cultivar and also shows the power of SSR markers in cultivar identification and intellectual property protection. Furthermore, the classification of nut shape is important for nut batch processing and for regional cultivar selection, which could be useful for the walnut industry.

Rechargeable sodium-ion batteries are proposed as the most appropriate alternative to lithium batteries due to the fast consumption of the limited lithium resources. Due to their improved safety, polyanion framework compounds have recently gained attention as potential candidates. With the earth-abundant element Fe being the redox center, the uniform carbon-coated Na

Sodium ion batteries are now attracting great attention, mainly because of the abundance of sodium resources and their cheap raw materials. 2D materials possess a unique structure for sodium storage. Among them, transition metal chalcogenides exhibit significant potential for rechargeable battery devices due to their tunable composition, remarkable structural stability, fast ion transport, and robust kinetics. Herein, ultrathin TiS2 nanosheets are synthesized by a shear-mixing method and exhibit outstanding cycling performance (386 mAh g(-1) after 200 cycles at 0.2 A g(-1)). To clarify the variations of galvanostatic curves and superior cycling performance, the mechanism and morphology changes are systematically investigated. This facile synthesis method is expected to shed light on the preparation of ultrathin 2D materials, whose unique morphologies could easily enable their application in rechargeable batteries.

The cathode materials in the Na-ion battery system are always the key issue obstructing wider application because of their relatively low specific capacity and low energy density. A graphene oxide (GO) wrapped composite, Na2Fe2(SO4)(3)@C@GO, is fabricated via a simple freeze-drying method. The as-prepared material can deliver a 3.8 V platform with discharge capacity of 107.9 mAh g(-1) at 0.1 C (1 C = 120 mA g(-1)) as well as offering capacity retention above 90% at a discharge rate of 0.2 C after 300 cycles. The well-constructed carbon network provides fast electron transfer rates, and thus, higher power density also can be achieved (75.1 mAh g(-1) at 10 C). The interface contribution of GO and Na2Fe2(SO4)(3) is recognized and studied via density function theory calculation. The Na storage mechanism is also investigated through in situ synchrotron X-ray diffraction, and pseudocapacitance contributions are also demonstrated. The diffusion coefficient of Na+ ions is around 10(-12)-10(-10.8) cm(2) s(-1) during cycling. The higher working voltage of this composite is mainly ascribed to the larger electronegativity of the element S. The research indicates that this well-constructed composite would be a competitive candidate as a cathode material for Na-ion batteries.

Rechargeable sodium-ion batteries are proposed as the most appropriate alternative to lithium batteries due to the fast consumption of the limited lithium resources. Due to their improved safety, polyanion framework compounds have recently gained attention as potential candidates. With the earth-abundant element Fe being the redox center, the uniform carbon-coated Na3.32 Fe2.34 (P2 O7 )2 /C composite represents a promising alternative for sodium-ion batteries. The electrochemical results show that the as-prepared Na3.32 Fe2.34 (P2 O7 )2 /C composite can deliver capacity of ≈100 mA h g-1 at 0.1 C (1 C = 120 mA g-1 ), with capacity retention of 92.3% at 0.5 C after 300 cycles. After adding fluoroethylene carbonate additive to the electrolyte, 89.6% of the initial capacity is maintained, even after 1100 cycles at 5 C. The electrochemical mechanism is systematically investigated via both in situ synchrotron X-ray diffraction and density functional theory calculations. The results show that the sodiation and desodiation are single-phase-transition processes with two 1D sodium paths, which facilitates fast ionic diffusion. A small volume change, nearly 100% first-cycle Coulombic efficiency, and a pseudocapacitance contribution are also demonstrated. This research indicates that this new compound could be a potential competitor for other iron-based cathode electrodes for application in large-scale Na rechargeable batteries.

Highlights • Sensitive DNA markers for identification of plant species are highly desirable. • Ubiquitin ligase gene region was first found to be useful for DNA marker development. • Ubiquitin ligase gene region will be another good source for DNA marker development. • Our methodology will improve evaluation and conservation of plant genetic diversity., Development of more sensitive nuclear DNA markers for identification of species, particularly closely allied taxa has been a challenging task that has attracted interest from scientists in fields of biotechnological development and genetic diversity detection. In this study, the sequence of the ubiquitin ligase gene (UBE3) region of nuclear DNA was tested for applicability and efficacy in revealing genetic diversity of walnut resources, with an emphasis on inter- and intra-specific levels. Analysis on genetic relationship among the taxa was conducted with the neighbor-joining (NJ) method. The number of variable bases in the UBE3 region was 20 sites. All nine taxa (species/variety/cultivars) were distinguished using the UBE3 sequence. In addition, each taxon was characterized molecularly with a unique nucleotide molecular formula using ten variable base sites derived from the nuclear DNA UBE3 gene sequence. This study presents a good complementary methodology for developing new DNA markers for identification of genus Juglans.

In this paper, we apply a time and frequency analysis method based on the complete ensemble empirical mode decomposition (CEEMD) in GPR signal processing. It decomposes the GPR signal into a sum of oscillatory components, with guaranteed positive and smoothly varying instantaneous frequencies. The key idea of this method relies on averaging the modes obtained by EMD applied to several realizations of Gaussian white noise added to the original signal. It can solve the mode mixing problem in empirical mode decomposition (EMD) method and improve the resolution of ensemble empirical mode decomposition (EEMD) when the signal has low signal noise ratio (SNR). First, we analyze the difference between the basic theory of EMD, EEMD and CEEMD. Then, we compare the time and frequency analysis results of different methods. The synthetic and real GPR data demonstrate that CEEMD promises higher spectral-spatial resolution than the other two EMDs method. Its decomposition is complete, with a numerically negligible error.