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The Newtonian gravitational constant, G, is one of the most fundamental constants of nature, but we still do not have an accurate value for it. Despite two centuries of experimental effort, the value of G remains the least precisely known of the fundamental constants. A discrepancy of up to 0.05 per cent in recent determinations of G suggests that there may be undiscovered systematic errors in the various existing methods. One way to resolve this issue is to measure G using a number of methods that are unlikely to involve the same systematic effects. Here we report two independent determinations of G using torsion pendulum experiments with the time-of-swing method and the angular-acceleration-feedback method. We obtain G values of 6.674184 × 10 and 6.674484 × 10 cubic metres per kilogram per second squared, with relative standard uncertainties of 11.64 and 11.61 parts per million, respectively. These values have the smallest uncertainties reported until now, and both agree with the latest recommended value within two standard deviations.

Two-terminal selectors with high nonlinearity, based on bidirectional threshold switching (TS) behaviors, are considered as a crucial element of crossbar integration for emerging nonvolatile memory and neuromorphic network. Although great efforts have been made to obtain various selectors, existing selectors cannot fully satisfy the rigorous standard of assorted memristive elements and it is in great demand to enhance the performance. Here, a new type of Ag/TaO x /TaO y /TaO x /Ag (x < y) selector based on homogeneous trilayered oxides is developed to attain the required parameters including bidirectional TS operation, a large selectivity of ≈10 10 , a high compliance current up to 1 mA, and ultralow switching voltages under 0.2 V. Tunable operation voltages can be realized by modulating the thickness of inserted TaO y . All-TaO x -based integrated 1S1R (one selector and one memristor) cells, prepared completely by magnetron sputtering and no need of a middle electrode, exhibit a nonlinear feature, which is quite characteristic for the crossbar devices, avoiding undesired crosstalk current issues. The tantalum-oxidebased homojunctions offer high insulation, low ion mobility, and rich interfaces, which is responsible for the modulation of Ag conductive filaments and corresponding high-performance cation-based selector. These findings might advance practical implementation of two-terminal selectors in emerging memories, especially resistive random access memories.tile memory and neuromorphic computing applications. [1] These applications are generally based on the crossbar array structure, where crosstalk current issues notoriously impede the read-write operations. [2] A great deal of efforts have been made to address the critical issue, and the two-terminal selector stands out for their simple structure and no need to compromise the scalability from numerous solutions. [3] Figure 1a illustrates the configuration of 1S1R (one selector and one memristor) integrated crossbar arrays. Recently, various selector elements have been introduced, including Schottky diodes, [4] metal-insulator transition, [5] fieldassisted superlinear threshold, [6] mixedionic-electronic conduction, [7] thermionic/ tunneling emission, [8] and electrochemical-metallization-based (ECM) threshold switching (TS). [9] One Schottky diode cascaded with one memristor (namely, 1D1R) is confined only to unipolar RRAM due to the unilateral conductivity of diodes. Selectors based on transport of ions and electrons are applicable to both unipolar and bipolar RRAM, but the gradually varied voltage-current (I-V) curves predestinates the moderate nonlinearity, [3b] which is not sufficient for the application of RRAM crossbar arrays.The ECM-based selector, which is based on the formation/ diffusion and Rayleigh instability of conductive filaments Nonvolatile MemoryThe ORCID identification number(s) for the author(s) of this article can be found under https://doi.

Although polyimine vitrimers are a promising and invaluable class of self‐healing materials owing to their great maneuverability and fast exchange of crosslinks without catalysts, it remains a challenge to improve the mechanical properties and thermal stability of the material by simply designing their internal structures. Herein, we report a conjugation polyimine vitrimer, which was prepared by polycondensation of terephthaldehyde, m‐xylylene diamine and tris (2‐aminoethyl) amine as crosslinker. The incorporation of m‐xylylene diamine endows the materials with an expanded conjugation structure, which greatly improves its mechanical properties and thermal stabilities. On the other hand, m‐xylylene diamine is less toxic and irritant than the linear aliphatic ones usually used, which makes the reactions more environment‐friendly. Results show that these materials have excellent mechanical properties and thermal stability, perform good flexibilities after immersed in water and show very short relaxation times at elevated temperatures. In addition, especially, they exhibit good self‐healing efficiency under the condition of heat, water and amine solvents without the need for any catalyst. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2531–2538

Nanorod-like Ni-rich LiNi0.6Co0.2Mn0.2O2 possesses more exposed active {010} facets and the volume change of lithiation/delithiation is as small as 2.12%.

A novel sandwich-like structured Co-Al LDH-Carbon Nanotube (CNT) composite has been successfully synthesized by the elegant combination between exfoliated Co-Al LDH nanosheets and modified CNTs, which was achieved through an electrostatic assembly method. It is worth noting that the negatively charged CNTs, sandwiched between the positively charged nanosheets via the electrostatic force, can not only expand the area of contact of electrolyte ions but also highly improve the conductivity. The as-prepared Co-Al LDHs-CNTs composite exhibited a high specific capacitance of 884 F g(-1) and a good cycle stability over 2000 cycles. Therefore, such a facile synthetic route to fabricate the layered structure composite may open a new strategy to prepare other composites with largely enhanced electrochemical properties, which can be of great promise in energy storage device application.

BACKGROUND: In this study, five microalgal species (Chlorella vulgaris, Chlorococcum sp. GD, Parachlorella kessleri TY, Scenedesmus quadricauda, and Scenedesmus obliquus) were cultivated in batch mode to evaluate their respective potential for the treatment of real aquaculture wastewater from a fishery. Subsequently, the microalga with the best performance was cultivated with different initial inoculation concentrations to evaluate the effect of initial inoculation on pollutant removal efficiency. RESULTS: When real aquaculture wastewater was inoculated with exogenous microalgae, the growth of both indigenous microalgae and bacteria was significantly inhibited. Pollutant removal was closely related to exogenous inoculationof microalgae. Parachlorella kessleri TY had high growth potential and pollutant removal capability in aquaculture wastewater, compared with the other four microalgae. When the wastewater was inoculated with low biomass concentrations of P. kessleri TY (50-100 mg L −1 ), it grew well and degraded most of the encountered pollutant. In particular, P. kessleri TY with 100 mg L −1 of inoculation concentration removed 94.4% of COD, 96.2% of ammonium, 99% of nitrite, 94.3% of nitrate, and 95.6% of phosphorus after 3 days of cultivation. CONCLUSIONS: Both the screening for microalgal species and the regulation of initial inoculation concentrations are promising approaches to enhance pollutant removal efficiency from real aquaculture wastewater. Determination of water qualityTo determine the water quality, the microalgal suspension was centrifuged at 5000 rpm for 5 min and the supernatant J Chem Technol Biotechnol 2019; 94: 900-910 /jctb up to 94.4%, 96.2%, 99%, 94.3%, and 95.6% for COD, ammonium, nitrite, nitrate, and total phosphorus, respectively. In the remaining tested inoculation concentrations (25, 50, 200, and 400 mg L −1 ), 77.8-88.9% of COD, 54.2-86.1% of ammonium, 64.1-91.7% of nitrite, 57.1-85.7% of nitrate, and 53-81.4% of total phosphorus were removed from the aquaculture wastewater J Chem Technol Biotechnol 2019; 94: 900-910

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