Identifying and decoupling many-body interactions in spin ensembles in diamond

We simulate the dynamics of varying density quasi-two-dimensional spin ensembles in solid-state systems, focusing on the nitrogen-vacancy centers in diamond. We consider the effects of various control sequences on the averaged dynamics of large ensembles of spins, under a realistic "spin-bath" environment. We reveal that spin locking is efficient for decoupling spins initialized along the driving axis, both from coherent dipolar interactions and from the external spin-bath environment, when the driving is two orders of magnitude stronger than the relevant coupling energies. Since the application of standard pulsed dynamical decoupling sequences leads to strong decoupling from the environment, while other specialized pulse sequences can decouple coherent dipolar interactions, such sequences can be used to identify the dominant interaction type. Moreover, a proper combination of pulsed decoupling sequences could lead to the suppression of both interaction types, allowing additional spin manipulations. Finally, we consider the effect of finite-width pulses on these control protocols and identify improved decoupling efficiency with increased pulse duration, resulting from the interplay of dephasing and coherent dynamics

A Facile Route to Fabricate Superhydrophobic Cu2O Surface for Efficient Oil–Water Separation

The mixture of insoluble organics and water seriously affects human health and environmental safety. Therefore, it is important to develop an efficient material to remove oil from water. In this work, we report a superhydrophobic Cu2O mesh that can effectively separate oil and water. The superhydrophobic Cu2O surface was fabricated by a facile chemical reaction between copper mesh and hydrogen peroxide solution without any low surface reagents treatment. With the advantages of simple operation, short reaction time, and low cost, the as-synthesized superhydrophobic Cu2O mesh has excellent oil–water selectivity for many insoluble organic solvents. In addition, it could be reused for oil–water separation with a high separation ability of above 95%, which demonstrated excellent durability and reusability. We expect that this fabrication technique will have great application prospects in the application of oil–water separation

Constituents leached by tomato seeds regulate the behavior of root-knot nematodes and their antifungal effects against seed-borne fungi

Germinating seeds can release diverse phytochemicals that repel, inhibit, or kill pathogens such as root-knot nematodes and seed-borne fungi. However, little is known about the composition of these phytochemicals and their effects on pathogens. In this study, we demonstrated that tomato seed exudates can attract the nematode Meloidogyne incognita using a dual-choice assay. Eighteen compounds were then isolated and identified from the exudates. Of these, esters (1-3), fatty acids (4-6), and phenolic acids (10-12) were proven to be the signaling molecules that facilitated the host-seeking process of second-stage juveniles (J2s) of nematodes, while alkaloids (17 and 18) disrupted J2s in locating their host. Furthermore, some phenolic acids and alkaloids showed antifungal effects against seed-borne fungi. In particular, ferulic acid (12) showed obvious activity against Aspergillus flavus (minimum inhibitory concentration (MIC), 32 μg/mL), while dihydrocapsaicin (17) showed noticeable activity against Fusarium oxysporum (MIC, 16 μg/mL). Overall, this study presents the first evidence that M. incognita can be attracted to or deterred by various compounds in seed exudates through identification of the structures of the compounds in the exudates and analysis of their effects on nematodes. Furthermore, some antifungal compounds were also found. The findings of this work suggest that seed exudates are new source for finding insights into the development of plant protective substances with nematocidal and antifungal effects

Improvement of Photocatalytic Performance for the g-C3N4/MoS2 Composite Used for Hypophosphite Oxidation

The synthesized g-C3N4/MoS2 composite was a high-efficiency photocatalytic for hypophosphite oxidation. In this work, a stable and cheap g-C3N4 worked as the chelating agent and combined with the MoS2 materials. The structures of the fabricated g-C3N4/MoS2 photocatalyst were characterized by some methods including X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectra (XPS). Moreover, the photocatalytic performances of various photocatalysts were measured by analyzing the oxidation efficiency of hypophosphite under visible light irradiation and the oxidation efficiency of hypophosphite using the g-C3N4/MoS2 photocatalyst which was 93.45%. According to the results, the g-C3N4/MoS2 composite showed a promising photocatalytic performance for hypophosphite oxidation. The improved photocatalytic performance for hypophosphite oxidation was due to the effective charge separation analyzed by the photoluminescence (PL) emission spectra. The transient photocurrent response measurement indicated that the g-C3N4/MoS2 composites (2.5 μA cm–2) were 10 times improved photocurrent intensity and 2 times improved photocurrent intensity comparing with the pure g-C3N4 (0.25 μA cm–2) and MoS2 (1.25 μA cm–2), respectively. The photocatalytic mechanism of hypophosphite oxidation was analyzed by adding some scavengers, and the recycle experiments indicated that the g-C3N4/MoS2 composite had a good stability

In Situ Separation and Collection of Oil from Water Surface via a Novel Superoleophilic and Superhydrophobic Oil Containment Boom

We have prepared a porous, superoleophilic and superhydrophobic miniature oil containment boom (MOCB) for the in situ separation and collection of oils from the surface of water. The MOCB was fabricated by a one-step electrodepositing of Cu₂O film on Cu mesh surface without using low surface energy materials. Oils on water surface could be fast contained in the MOCB while water was completely repelled out of the MOCB, thus achieving the separation of oil from water surface. In addition, the contained oil in the MOCB could be in situ collected easily by a dropper, thus achieving the collection of oil. Moreover, the MOCB could be reused for many times in the oil–water separating process with large separation abilities more than 90%. The MOCB also possessed excellent water pressure resistance for about 164 mm water column and good corrosion resistance in simulating seawater. Therefore, the findings in the present study might offer a simple, fast, and low-cost method for the in situ separation and collection of oil spills on seawater surface

In Situ Separation and Collection of Oil from Water Surface via a Novel Superoleophilic and Superhydrophobic Oil Containment Boom

We have prepared a porous, superoleophilic and superhydrophobic miniature oil containment boom (MOCB) for the in situ separation and collection of oils from the surface of water. The MOCB was fabricated by a one-step electrodepositing of Cu₂O film on Cu mesh surface without using low surface energy materials. Oils on water surface could be fast contained in the MOCB while water was completely repelled out of the MOCB, thus achieving the separation of oil from water surface. In addition, the contained oil in the MOCB could be in situ collected easily by a dropper, thus achieving the collection of oil. Moreover, the MOCB could be reused for many times in the oil–water separating process with large separation abilities more than 90%. The MOCB also possessed excellent water pressure resistance for about 164 mm water column and good corrosion resistance in simulating seawater. Therefore, the findings in the present study might offer a simple, fast, and low-cost method for the in situ separation and collection of oil spills on seawater surface

Superhydrophobic Cu Mesh Combined with a Superoleophilic Polyurethane Sponge for Oil Spill Adsorption and Collection

We present a miniature collector for the adsorption and collection of oil spill. The collector composed of a superhydrophobic copper mesh miniature box embedded with a superoelophilic polyurethane sponge. The superhydrophobic Cu mesh was fabricated by a simple immersing method, and the PU sponge is a commercial available material with superoleophilicity in itself. The miniature collector can adsorb different oils on water surface in the pores of the superhydrophilic PU sponge while repelled water due to the superhydrophobicity of the mesh. In addition, the adsorbed oils could be easily separated from the sponge by squeezing and then be collected for reuse. After the separation of adsorbed oil, the sponge could be used repeatedly with high separation efficiency. Furthermore, the as-prepared Cu mesh possesses stability in various solvents and corrosion resistance in NaCl aqueous solution. The findings might provide a simple method for oils spill cleanup

Superoleophobic Textured Copper Surfaces Fabricated by Chemical Etching/Oxidation and Surface Fluorination

We report a convenient route to fabricate superoleophobic surfaces (abridged as SOS) on copper substrate by combining a two-step surface texturing process (first, the substrate is immersed in an aqueous solution of HNO₃ and cetyltrimethyl ammonium bromide, and then in an aqueous solution of NaOH and (NH₄)₂S₂O₈) and succeeding surface fluorination with 1H,1H,2H,2H-perfluorodecanethiol (PFDT) or 1-decanethiol. The surface morphologies and compositions were characterized by field emission scanning electron microscopy and X-ray diffraction, respectively. The results showed that spherical micro-pits (SMP) with diameter of 50–100 μm were formed in the first step of surface texturing; in the second step, Cu­(OH)₂ or/and CuO with structures of nanorods/microflowers/microballs were formed thereon. The surface wettability was further assessed by optical contact angle meter by using water (surface tension of 72.1 mN m^–1 at 20°C), rapeseed oil (35.7 mN m^–1 at 20°C), and hexadecane (25.7 mN m^–1 at 20°C) as probe liquids. The results showed that, as the surface tension decreasing, stricter choosing of surface structures and surface chemistry are required to obtain SOS. Specifically, for hexadecane, which records the lowest surface tension, the ideal surface structures are a combination of densely distributed SMP and nanorods, and the surface chemistry should be tuned by grafted with low-surface-energy molecules of PFDT. Moreover, the stability of the so-fabricated sample was tested and the results showed that, under the testing conditions, superhydrophobicity and superoleophobicity may be deteriorated after wear/humidity resistance test. Such deterioration may be due to the loss of outermost PFDT layer or/and the destruction of the above-mentioned ideal surface structures. For UV and oxidation resistance, the sample remained stable for a period of 10 days

Superhydrophobic and Superoleophilic Miniature Device for the Collection of Oils from Water Surfaces

We develop a simple strategy for the collection of oil spill using a miniature device. The device was enfolded from a sheet of copper mesh with surface superhydrophobicity and superoleophilicity. The copper mesh was fabricated through a simple thermal oxidation and surface modification process. The miniature device adsorbed various oils from the surface of oil–water mixture in its pores while repelling water completely. After the pores were full of oil, only oil could infiltrate into the device through the pores automatically and was finally concentrated into the device, showing its oil–water separating ability. Importantly, the concentrated oil in the device could be taken away by a dropper or pumped out, thus achieving the collection of oil for reuse. Additionally, after the concentrated oil was taken away, the device could be used in the next oil–water separating cycle without apparent decrease of its separation ability. Therefore, the findings in this work may offer a new strategy for the collection and reuse of various kinds of oils and other organic compounds from water surfaces