A lithium-ion conducting gel polymer electrolyte (GPE) membrane containing PEO as a polymer host and liquid electrolyte has been prepared by a simple one-step procedure. The prepared electrolyte ...membrane exhibits a good ionic conductivity of 3.3 × 10 −3 S cm −1 and high lithium transference number of 0.76 at room temperature. Meanwhile, the gel polymer electrolyte membrane shows very good thermal stability. A Li/GPE/LiFeO 4 cell was fabricated to demonstrate the electrochemical performance of the GPE. The cell exhibits good cycling stability with a high capacity retention of 81% after 500 cycles and as good a rate performance as LiFeO 4 tested in liquid electrolyte.
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IJS, KILJ, NUK, UL, UM, UPUK
In this paper, the properties and operation of the virtual-space-vector pulse-width modulation (PWM) for a three-level neutral-point-clamped inverter with unbalanced dc-links are studied. By ...quantitatively analyzing the characteristics of the revised space-vector diagram (SVD) with unbalanced dc-links, the defined virtual SVD (VSVD) for the unbalanced case is theoretically proven identical to the VSVD of the conventional virtual-space-vector PWM (VSVPWM) strategy with balanced dc-links. The well-developed and fast-processing methods to calculate the durations of the nearest three virtual vectors for the conventional VSVPWM can be directly utilized. In addition, a control strategy to realize the asymmetric control of the dc-link voltages with VSVPWM is also studied, and this method can adjust the unbalancing degree with a high accuracy for any modulation indexes and load power factors. Simulated and experimental results are given to validate the effectiveness.
Reaching the quantum optics limit of strong light-matter interactions between a single exciton and a plasmon mode is highly desirable, because it opens up possibilities to explore room-temperature ...quantum devices operating at the single-photon level. However, two challenges severely hinder the realization of this limit: the integration of single-exciton emitters with plasmonic nanostructures and making the coupling strength at the single-exciton level overcome the large damping of the plasmon mode. Here, we demonstrate that these two hindrances can be overcome by attaching individual J aggregates to single cuboid Au@Ag nanorods. In such hybrid nanosystems, both the ultrasmall mode volume of ∼71 nm^{3} and the ultrashort interaction distance of less than 0.9 nm make the coupling coefficient between a single J-aggregate exciton and the cuboid nanorod as high as ∼41.6 meV, enabling strong light-matter interactions to be achieved at the quantum optics limit in single open plasmonic nanocavities.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
Efficient metal-free electrocatalysts for oxygen reduction reaction (ORR) are highly expected in future low-cost energy systems. We have successfully prepared crumpled, sheet-like, sulfur-doped ...graphene by magnesiothermic reduction of easily available, low-cost, nontoxic CO2 (in the form of Na2CO3) and Na2SO4 as the carbon and sulfur sources, respectively. At high temperature, Mg can reduce not only carbon in the oxidation state of +4 in CO3(2-) to form graphene, but also sulfur in SO4(2-) from its highest (+6) to lowest valence which was hybridized into the carbon sp(2) framework. Various characterization results show that sulfur-doped graphene with only few layers has an appropriate sulfur content, hierarchically robust porous structure, large surface area/pore volume, and highly graphitized textures. The S-doped graphene samples exhibit not only a high activity for ORR with a four-electron pathway, but also superior durability and tolerance to MeOH crossover to 40% Pt/C. This is mainly ascribed to the combination of sulfur-related active sites and hierarchical porous textures, facilitating fast diffusion of oxygen molecules and electrolyte to catalytic sites and release of products from the sites.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Recently, nano-cesium tungsten bronze (CsxWO3) is found to be a new candidate for the application in solar filter due to its high visible transmittance and excellent near-infrared shielding ability. ...However, a typical two-dimensional (2D) CsxWO3 has not been reported since 2D nanomaterials have attracted great attention due to their fascinating properties, e.g., graphene. Herein, a novel synthesis system and related mechanisms are tried to develop for synthesizing 2D CsxWO3 via hydrothermal method, which an original inspiration derived from the morphology control of sulfides. The results indicate that morphology modifier represents a new strategy in which thiourea and oleylamine interact synergistically rather than independently to synthesize 2D Cs0.3WO3. The more regular and larger the rectangular nanosheet, the broader and stronger the light absorption, the rectangular Cs0.3WO3 nanosheets with the maximum size are synthesized from thiourea, oleylamine and HCl concentrations of 4, 0.061 and 320 mmol/L, respectively, and exhibit a broad and strong absorption spectrum. The above nanosheet shows excellent instantaneous photo-thermal conversion property resulting in an obvious temperature increases from 20 °C to 88.5 °C when it was irradiated by 50 W halogen lamp for 10 s. Finally, both chemical reaction and morphological evolution in the synthesis processes are revealed.
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•Thiourea and oleylamine synergistically modify two-dimensional Cs0.3WO3 morphology.•The more regular and larger the nanosheet, the broader and stronger light absorption.•Thiourea, oleylamine and HCl are 4, 0.061 and 320 mmol/L, getting the maximum size.•The mechanism of chemical and morphological for two-dimensional Cs0.3WO3 is revealed.•The temperature of the largest rectangular-sheets reaches 88.5 °C after irradiation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
Nonlinear optical rectification and the second-harmonic generation (SHG) in semi-parabolic and semi-inverse squared quantum wells are theoretically investigated within the framework of the ...compact-density-matrix approach and iterative method. The wave functions and the energy levels are obtained by using the effective mass approximation. It is found that nonlinear optical rectification coefficients and the second-harmonic generation are strongly affected not only by the confinement frequency ω0, but also by the parameter β.
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Segmenting common objects that have variations in color, texture and shape is a challenging problem. In this paper, we propose a new model that efficiently segments common objects from multiple ...images. We first segment each original image into a number of local regions. Then, we construct a digraph based on local region similarities and saliency maps. Finally, we formulate the co-segmentation problem as the shortest path problem, and we use the dynamic programming method to solve the problem. The experimental results demonstrate that the proposed model can efficiently segment the common objects from a group of images with generally lower error rate than many existing and conventional co-segmentation methods.
Four low carbon bainite steels were designed to investigate the effects of Mo and Nb addition on bainitic transformation, microstructures and properties by metallographic method and dilatometry. The ...results show that single Nb addition retards bainitic transformation in low carbon bainite steels, although it can improve strength by refining microstructures. Moreover, Mo addition is effective to improve the strength of low carbon bainite steel by promoting bainitic transformation and single Mo addition has a better strengthening effect than single Nb addition. Further, in Mo bearing steel, Nb addition refines bainite sheaves, but meanwhile hinders bainitic transformation because of smaller austenite grains. Consequently, the composite strengthening effect of Mo and Nb addition has little improvement compared with individual addition of Mo in low carbon bainite steels.
•Whilst the addition of Nb improves the strength of alloy steel through grain refinement, it hinders bainitic transformation.•The combined effect of Nb and Mo alloying simultaneously promotes grain refinement and bainitic transformation.•Mo addition is effective to improve the strength of low carbon bainite steel by promoting bainitic transformation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK
In this paper, we introduce a novel point-to-surface representation for 3D point cloud learning. Unlike the previous methods that mainly adopt voxel, mesh, or point coordinates, we propose to tackle ...this problem from a new perspective: learn a set of quadratic terms based static and global reference surfaces to describe 3D shapes, such that the coordinates of a 3D point (x, y, z) can be extended to quadratic terms (xy, xz, yz, <inline-formula> <tex-math notation="LaTeX">\ldots </tex-math></inline-formula>) and transformed to the relationship between the local point and the global reference surfaces. Then, the static surfaces are changed into dynamic surfaces by adaptive contribution weighting to improve the descriptive capability. Towards this end, we propose our point-to-surface representation, a new representation for 3D point cloud learning that has not been attempted before, which can assemble local and global geometric information effectively by building connections between the point cloud and the learned reference surfaces. Given 3D points, we show how the reference surfaces are constructed, and how they are inserted into the 3D learning pipeline for different tasks. The experimental results confirm the effectiveness of our new representation, which has outperformed the state-of-the-art methods on the tasks of 3D classification and segmentation.
Arsenic is known as a toxic metalloid, which primarily exists in inorganic form As(III) and As(V) and can be transformed by microbial redox processes in the natural environment. As(III) is much more ...toxic and mobile than As(V), hence microbial arsenic redox transformation has a major impact on arsenic toxicity and mobility which can greatly influence the human health. Our main purpose was to investigate the distribution and diversity of microbial arsenite-resistant species in three different arsenic-contaminated soils, and further study the As(III) resistance levels and related functional genes of these species.
A total of 58 arsenite-resistant bacteria were identified from soils with three different arsenic-contaminated levels. Highly arsenite-resistant bacteria (MIC > 20 mM) were only isolated from the highly arsenic-contaminated site and belonged to Acinetobacter, Agrobacterium, Arthrobacter, Comamonas, Rhodococcus, Stenotrophomonas and Pseudomonas. Five arsenite-oxidizing bacteria that belonged to Achromobacter, Agrobacterium and Pseudomonas were identified and displayed a higher average arsenite resistance level than the non-arsenite oxidizers. 5 aoxB genes encoding arsenite oxidase and 51 arsenite transporter genes 18 arsB, 12 ACR3(1) and 21 ACR3(2) were successfully amplified from these strains using PCR with degenerate primers. The aoxB genes were specific for the arsenite-oxidizing bacteria. Strains containing both an arsenite oxidase gene (aoxB) and an arsenite transporter gene (ACR3 or arsB) displayed a higher average arsenite resistance level than those possessing an arsenite transporter gene only. Horizontal transfer of ACR3(2) and arsB appeared to have occurred in strains that were primarily isolated from the highly arsenic-contaminated soil.
Soils with long-term arsenic contamination may result in the evolution of highly diverse arsenite-resistant bacteria and such diversity was probably caused in part by horizontal gene transfer events. Bacteria capable of both arsenite oxidation and arsenite efflux mechanisms had an elevated arsenite resistance level.
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