A new high speed charge and high efficiency Li-Ion battery charger interface using pulse control technique

A new Li-Ion battery charger interface (BCI) using pulse control (PC) technique is designed and analyzed in this paper. Thanks to the use of PC technique, the main standards of the Li-Ion battery charger, i.e. fast charge, small surface area and high efficiency, are achieved. The proposed charger achieves full charge in forty-one minutes passing by the constant current (CC) charging mode which also included the start-up and the constant voltage mode (CV) charging mode. It designed, simulated and layouted which occupies a small size area 0.1 mm2 by using Taiwan Semiconductor Manufacturing Company 180 nm complementary metal oxide semi-conductor technology (TSMC 180 nm CMOS) technology in Cadence Virtuoso software. The battery voltage VBAT varies between 2.9 V to 4.35 V and the maximum battery current IBAT is 2.1 A in CC charging mode, according to a maximum input voltage VIN equal 5 V. The maximum charging efficiency reaches 98%.

Identification and characterization of two drug-like fragments that bind to the same cryptic binding pocket of Burkholderia pseudomallei DsbA

Disulfide-bond-forming proteins (Dsbs) play a crucial role in the pathogenicity of many Gram-negative bacteria. Disulfide-bond-forming protein A (DsbA) catalyzes the formation of the disulfide bonds necessary for the activity and stability of multiple substrate proteins, including many virulence factors. Hence, DsbA is an attractive target for the development of new drugs to combat bacterial infections. Here, two fragments, bromophenoxy propanamide (1) and 4-methoxy-N-phenylbenzenesulfonamide (2), were identified that bind to DsbA from the pathogenic bacterium Burkholderia pseudomallei, the causative agent of melioidosis. The crystal structures of oxidized B. pseudomallei DsbA (termed BpsDsbA) co-crystallized with 1 or 2 show that both fragments bind to a hydrophobic pocket that is formed by a change in the side-chain orientation of Tyr110. This conformational change opens a `cryptic' pocket that is not evident in the apoprotein structure. This binding location was supported by 2D-NMR studies, which identified a chemical shift perturbation of the Tyr110 backbone amide resonance of more than 0.05 p.p.m. upon the addition of 2 mM fragment 1 and of more than 0.04 p.p.m. upon the addition of 1 mM fragment 2. Although binding was detected by both X-ray crystallography and NMR, the binding affinity (K d) for both fragments was low (above 2 mM), suggesting weak interactions with BpsDsbA. This conclusion is also supported by the crystal structure models, which ascribe partial occupancy to the ligands in the cryptic binding pocket. Small fragments such as 1 and 2 are not expected to have a high energetic binding affinity due to their relatively small surface area and the few functional groups that are available for intermolecular interactions. However, their simplicity makes them ideal for functionalization and optimization. The identification of the binding sites of 1 and 2 to BpsDsbA could provide a starting point for the development of more potent novel antimicrobial compounds that target DsbA and bacterial virulence.

Determination of band alignment between GaOx and boron doped diamond for selective-area-doped termination structure

n-GaOx thin film is deposited on the single crystal boron doped diamond through RF magnetron sputtering to form a pn heterojunction. The n-GaOx thin film presents a small surface roughness and a large optical band gap of 4.85 eV. In addition, the band alignment is measured by using X-ray photoelectron spectroscopy to evaluate the heterojunction property. The GaOx/diamond heterojunction shows a type-II staggered band configuration with the valence and conduction band offsets are of 1.28 eV and 1.93 eV, respectively. Those results confirm the feasibility to use n-GaOx as termination structure for diamond power device.

The properties of highly concentrated aqueous CH3COOK/Na binary electrolyte and its use in sodium-ion batteries

Highly concentrated aqueous binary solutions of acetate salts are emerging as promising systems for advanced energy storage applications. Together with superior solubility of CH3COOK helpful in achieving water-in-salt electrolyte concentrations, the presence of CH3COOLi or CH3COONa permits intercalation of desired cations in electrode crystalline phases. Although these systems have captured profound scientific attention in recent years, a fundamental understanding of their physicochemical properties is still lacking. In this work, the thermal, rheological, transport, and electrochemical properties for a series of solutions comprising of 20 mol kg-1 of CH3COOK with different concentrations of CH3COONa are reported and discussed. The most concentrated solution, i.e., 20 mol kg-1 of CH3COOK with 7 mol kg-1 of CH3COONa came out to be the best in terms of a compromise between transport properties and electrochemical stability window. Such a solution has a conductivity of 21.2 mS cm-1 at 25°C and shows a stability window up to 3 V in “ideal” conditions, i.e., using small surface area and highly electrocatalytic electrode in a flooded cell. As a proof of concept of using this solution in sodium-ion batteries, carbon-coated LiTi2(PO4)3 (NASICON) demonstrated the ability to reversibly insert and de-insert Na+ ions at about -0.7 V vs. SHE with a first cycle anodic capacity of 85 mAh g-1, average charge efficiency of 96% at low current and a 90% capacity retention after 60 cycles. The very good kinetic properties of the interface are also demonstrated by the low value of activation energy for the charge transfer process (0.12 eV).

Analysis of Surface Properties of Nickel Alloy Elements Exposed to Impulse Shot Peening with the Use of Positron Annihilation

The paper presents the results of experimental studies on the impact of impulse shot peening parameters on surface roughness (Sa, Sz, Sp, Sv), surface layer microhardness, and the mean positron lifetime (τmean). In the study, samples made of the Inconel 718 nickel alloy were subjected to impulse shot peening on an originally designed stand. The variable factors of the experiment included the impact energy, the diameter of the peening element, and the number of impacts per unit area. The impulse shot peening resulted in changes in the surface structure and an increase in surface layer microhardness. After the application of impulse shot peening, the analyzed roughness parameters increased in relation to post-milling values. An increase in microhardness was obtained, i.e., from 27 HV 0.05 to 108 HV 0.05 at the surface, while the maximum increase the microhardness occur at the depth from 0.04 mm to 0.08 mm. The changes in the physical properties of the surface layer were accompanied by an increase in the mean positron lifetime τmean. This is probably related to the increased positron annihilation in point defects. In the case of small surface deformations, the increase in microhardness was accompanied by a much lower increase in τmean, which may indicate a different course of changes in the defect structure consisting mainly in modification of the dislocation system. The dependent variables were subjected to ANOVA analysis of variance (it was one-factor analysis), and the effect of independent variables was evaluated using post-hoc tests (Tukey test).

Controlling Eutrophication via Surface Aerators in Irregular-Shaped Urban Ponds

Surface aerators have often been introduced in urban ponds for esthetics, but their roles in remediating water quality are less understood. Effects of surface aerators on controlling eutrophication were examined in two urban ponds, in which anaerobic odors and cyanobacterial blooms had occurred and several aerators had been installed. In one of the ponds, a dramatic improvement in dissolved oxygen (DO) (from 1.8 to 8.1 mg L−1) and total phosphorus (TP) (from 1.6 to 0.4 mg L−1) was evident based on the comparison before and after the aeration. Although cyano-bloom did not occur, phytoplankton was dominated by cyanobacteria Microcystis species in both periods. Chlorophyll a (Chl-a) increased (from 29 to 51 μg L−1) and water transparency decreased (from 81 to 27 cm) after the aeration. In the other pond with an irregular shape, water quality was monitored two years after the installation to examine seasonal variation in trophic state and its spatial variation associated with aerator distribution. The water was mixed vertically well for the whole pond, as indicated by small surface-to-bottom differences in temperature. DO decreased in summer after rainfall but was always >5.7 mg L−1. Total nitrogen (TN) and TP were 0.8–2.3 and 0.03–0.07 mg L−1, respectively, and no cyano-blooms were observed across sites throughout the year. Phytoplankton was dominated by green algae and diatom species, which may be favored by the lower phosphorus level of the pond. Chl-a was higher and transparency was lower in the north side, which had more aerators and less shade from trees and buildings. These results suggest that surface aerators increased DO by vertical and horizontal mixing of water, reduced phosphorus release from sediment, and prevented cyano-bloom occurrence, but they did not improve Chl-a level and transparency. Rather, aeration can promote algal growth, and thus, additional purifying measures such as filtration and contact oxidation are required to further improve the trophic state of these ponds.

THE MACROPHYTE FLORA AND VEGETATION OF THE PAUČKO LAKE (MT. KONJUH)

UDK: 581.9:574.5 (497.6) (285) The study presents the first data on biodiversity of macrophyte flora and vegetation of Paučko Lake, which is recognized as an area of great natural, landscape and hydrological value in the Protected Landscape “Konjuh”. Paučko Lake has a small surface and it’s located at 711 m a.s.l. in the catchment area of the Drinjača River. The aquatic and marsh vegetation were studied during spring and summer in 2018 using the traditional Zürich-Montpellier approach. The vegetation of Paučko Lake is comprised of aquatic and marsh associations of the classes Potamogetonetea Klika in Klika et Novák 1941 and Phragmito-Magnocaricetea Klika in Klika et Novák 1941. The following aquatic and marsh plant associations were identified: Myriophyllo-Potametum Soó 1934, Scirpo-Phragmitetum australis W. Koch 1926, Thelypterido palustris-Phragmitetum australis Kuiperex van Donselaar et al. 1961, Schoenoplectetum lacustris Chouard 1924, Typhetum latipholiae Lang. 1973 and Scirpetum silvatici Ht et H-ić prov. (in Ht et al.1974). Rare vulnerable taxa Thelypteris palustris Schott and Menyanthes trifoliata L. were recorded in emerged littoral communities, whose habitats are under successional changes caused by excessive macrophyte overgrowth by competitor species. Restoration measures are necessary to be taken to preserve the habitats of endangered species of the Paučko Lake.

Hydrodynamic Analysis of Self-Propulsion Performance of Wave-Driven Catamaran

The wave-driven catamaran is a small surface vehicle driven by ocean waves. It consists of a hull and hydrofoils, and has a multi-body dynamic structure. The process of moving from static state to autonomous navigation driven by ocean waves is called “self-propulsion”, and reflects the ability of the wave-driven catamaran to absorb oceanic wave energy. Considering the importance of the design of the wave-driven catamaran, its self-propulsion performance should be comprehensively analysed. However, the wave-driven catamaran’s multi-body dynamic structure, unpredictable dynamic and kinematic responses driven by waves make it difficult to analyse its self-propulsion performance. In this paper, firstly, a multi-body dynamic model is established for wave-driven catamaran. Secondly, a two-phase numerical flow field containing water and air is established. Thirdly, a numerical simulation method for the self-propulsion process of the wave-driven catamaran is proposed by combining the multi-body dynamic model with a numerical flow field. Through numerical simulation, the hydrodynamic response, including the thrust of the hydrofoils, the resistance of the hull and the sailing velocity of the wave-driven catamaran are identified and comprehensively analysed. Lastly, the accuracy of the numerical simulation results is verified through a self-propulsion test in a towing tank. In contrast with previous research, this method combines multi-body dynamics with computational fluid dynamics (CFD) to avoid errors caused by artificially setting the motion mode of the catamaran, and calculates the real velocity of the catamaran.