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A decarboxylative protocol has been developed toward a range of carbocycles. The key success is based on the use of a batch of newly designed cyclic carbonates as substrates that can provide carbon-carbon zwitterion intermediate under palladium catalysis. The kinetics of the reactions are controllable toward either strained seven- or thermodynamically more favored five-membered carbocycles. The release of this chemistry will shed light on the synthesis of complex and valuable cyclic structures.

In nature, ultrafast signal transfer based on ion transport, which is the foundation of biological processes, commonly works in a hydrogel–water mixed mechanism. Inspired by organisms’ hydrogel-based system, we introduce hydrogel into nanofluidics to prepare a hydrogel hybrid membrane. The introduction of a space charged hydrogel improves the ion selectivity evidently. Also, a power generator based on the hydrogel hybrid membrane shows an excellent energy conversion property; a maximum power density up to 11.72 W/m2 is achieved at a 500-fold salinity gradient. Furthermore, the membrane shows excellent mechanical properties. These values are achievable, which indicates our membrane’s huge potential applications in osmotic energy conversion., Our robust hydrogel hybrid membrane, which works in an organism-like hydrogel−water ambient, shows excellent ion selectivity and high-power output.

A kinetic investigation into the formation of spinel from alumina (Al2O3) and magnesia (MgO) powder compaction with a stoichiometric mixing molar ratio of 1:1 was conducted in the temperature range of 1573 K to 1773 K over a certain time interval up to 25 h. The samples were pressed at pressures of 125, 375 and 750 MPa. The progress of the reaction was evaluated by monitoring the expansion ratio instead of the thickness of the spinel layer that was generated. The expansion ratio increases with increasing pressing pressure and holding time, and high temperature favored spinel formation. However, densification was observed at temperatures above 1673 K due to the occurrence of sintering between the powders. A kinetic model taking electrochemical potential as the driving force of the reaction was established, and the apparent activation energy was calculated to be 310.6 kJ/mol in the temperature range between 1573 K and 1673 K. The reaction was controlled by the inter-diffusion of Al3+ and Mg2+ ions in the spinel layer that was formed.

Biological ion channel-based mass transport and signal transduction play a crucial role in physiological activities, and biomimetic nanochannels in aqueous solutions for ion transport regulation have been extensively studied. Few studies on non-aqueous systems, gel-based nanochannels, mainly focus on the charged gel network or embedded electrolytes. However, the basic issue of how a nanoscale gel network affects the ion transport in nanochannels has been neglected. Here, we demonstrate a non-aqueous biomimetic nanochannel system by employing the agarose hydrogel in conical nanochannels. To tune the hydrogel network by adjusting the gel concentration, the ion transport behavior in gel-based nanochannels is systemically investigated. The experimental results show that the ion transport behaviors in gel-nanochannels with 2% gel present similar ion selectivity and rectification performance to the aqueous system, indicating fast investigation of gel-based systems with the knowledge of the extensively studied aqueous systems. Furthermore, a gel-based solid-state diode and logic circuits were fabricated.

Bioinspired nanochannels whose functions are similar to those of the biological prototypes attract increasing attention due to their potential applications in signal transmission, mass transport, energy conversion, etc. Up to now, however, it is still a challenge to extract low-grade waste heat from the ambient environment in an aqueous solution. Herein, a thermo-driven nanofluidic system was developed to extract low-grade waste heat efficiently based on directed ionic transport at a micro-/nanoscale. A steady streaming current increases linearly with the temperature gradient, achieving as high as 14 nA at a temperature gradient of 47.5 °C (δT = 47.5 °C) through a 0.5 cm2 porous membrane (106 cm−2). And an unexpected theoretical power of 25.48 pW using a single nanochannel at a temperature difference of 40 °C has been achieved. This bioinspired multifunctional system broadens thermal energy recovery and will accelerate the evolution of nanoconfined mass transport for practical applications.

Capturing the osmotic power between seawater and river water is thought to be an effective strategy to solve the global energy crisis. The existing designs of membrane-based nanofluids with high io...

In this paper, the phase field method is used to study the multi control factors during directional solidification sidebranching growth of Al-Si alloy. The effects of primary dendritic spacing, pulling velocity, temperature gradient and thermal noise on the evolution of sidebranch are studied. As the primary dendritic spacing increases, the number of secondary branches symmetrically growing on both sides of the primary dendrites increases and the secondary branches are more developed; The increase of the pulling velocity and the temperature gradient can increase the instability of the sidebranch and the degree of solute enrichment in the secondary branches gap. Sidebranch remelting and coarsening will occur when the pulling velocity and temperature gradient are large; Without changing the tip morphology and steady-state behavior of the dendrite, appropriate thermal noise can trigger the sidebranching and make the sidebranch on both sides of the dendrite asymmetrically growth.

In this study, the phase field method was used to study the multi-controlling factors of dendrite growth in directional solidification. The effects of temperature gradient, propelling velocity, thermal disturbance and growth orientation angle on the growth morphology of the dendritic growth in the solid/liquid interface were discussed. It is found that the redistribution of solute leads to multilevel cavity and multilevel fusion to form multistage solute segregation, and the increase of temperature gradient and propelling velocity can accelerate the dendrite growth of directional solidification, and also make the second dendrites more developed, which reduces the primary distance and the solute segregation. When the temperature gradient is large, the solid-liquid interface will move forward in a flat interface mode, and the thermal disturbance does not affect the steady state behavior of the directionally solidified dendrite tip. It only promotes the generation and growth of the second dendrites and forms the asymmetric dendrite. Meanwhile, it is found that the inclined dendrite is at a disadvantage in the competitive growth compared to the normal dendrite, and generally it will disappear. When the inclination angle is large, the initial primary dendrite may be eliminated by its secondary or third dendrite.

We study the pairing symmetry of ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$ through the group-theoretical approach. We emphasize the role of pairing interaction between the quasi-one-dimensional (Q1D) ${d}_{xz/yz}$ and quasi-two-dimensional (Q2D) ${d}_{xy}$ orbitals. It is found that two degenerate interorbital time-reversal-invariant(TRI) $p$-wave pairings, one spin singlet and the other spin triplet with out-of-plane $\mathbit{d}$ vector, could be the most promising candidates. Several important physical quantities are presented, including the near-nodal gap structure, the unchanged out-of-plane Knight shift, and no splitting of transition under strain, which are consistent with the experiments. In addition, these $p$-wave pairings shed light on resolving the contradiction between the time-reversal breaking and reduced in-plane Knight shift measurements. As the system reaches the Van Hove singularity under applied strain, the pairing symmetry would become a $d$-wave pairing mainly consisting of interorbital components, which could be responsible for the strained $3K$ phase.

With the development of technology and society, ocean development is becoming more and more necessary and frequent. During this process, marine biofouling is an extensive problem, causing economic loss and operational problems. A lot of attempts have been made to overcome these troubles. However, there is still an urgent need to develop an efficient and environmentally friendly method to resist marine antifouling. As reported, the adhesion of diatoms is one of the key steps in the marine fouling process. In this research, for the first time, 3-(trimethoxysilyl)propylmethacrylate (TMSPMA), which is a synthetic orthosilicic acid analog (SOSA) after hydrolysis, is used as an anti-diatom agent against diatom adhesion in the preparation of a SOSA hydrogel. Detailed investigations suggest that the hydrogel with the SOSA shows excellent anti-diatom adhesion properties (0 Navicula and 0.2 ± 0.5 diatoms mm−2 of Nitzschia closterium adhered). The results also indicate that the SOSA anti-diatom effects are targeted; only the organisms that attempted to adhere to the surface of the SOSA hydrogel are affected. Owing to its high efficiency and environmentally-friendly properties, SOSA hydrogels have great potential for marine antifouling applications.

Liu, C.; Huang, Z., and Chen, W., 2017. A numerical study of a submerged horizontal heaving plate as a breakwater. Using a nonlinear numerical wave tank (NWT) based on potential flow, a submerged horizontal plate heaving in regular waves was simulated, and its performance as a breakwater was examined. The NWT is based on a Mixed Eulerian-Lagrangian formulation and a de-singularized boundary integral equation method. The viscous effect on the motion of the plate is estimated by a linear damping coefficient, and the natural frequency of the heaving plate is controlled by the system stiffness. Compared with a fixed submerged horizontal plate, our results showed that the heaving motion of the plate with a critical stiffness could reduce the wave-transmission coefficient to almost zero and effectively suppress the free and locked waves on the leeside of the plate. The new type of breakwater can be an ideal alternative for small marinas and recreational harbors.

We study the possibility of topological superconductivity in the noncentrosymmetric monolayer and trilayer TaS$_2$ with out-of-plane mirror symmetry. A gapless time-reversal invariant f+s-wave pairing state with even mirror parity is found to be a promising candidate. This mixing state holds 12(36) nodes at the Fermi pockets around $\Gamma$ for monolayer(trilayer) case and its unconventional superconductivity is consistent with the STM experiments observed in 2$H$-TaS$_2$ thin flakes. Furthermore, with doping or under uniaxial pressure for trilayer 2$H$-TaS$_2$, large-Chern-number time-reversal symmetry breaking mixing states between d+id- and p-ip-wave pairings can be realized in the phase diagram., Comment: 11 pages, 5 figures

We study transport properties of topological Weyl nodal-line semimetals(NLSs). Starting from a minimal lattice model with a single nodal loop, and by focusing on a normal-metal-NLS-normal-metal junction, we investigate the dependence of the novel transport behavior on the orientation of the nodal loop. When the loop is parallel to the junction interfaces, the transmitted current is found to be nearly fully spin-polarized. Correspondingly, there exists a spin orientation, along which the incident electrons would be totally reflected. An unusual resonance of half transmission with the participation of surface states also occurs for a pair of incident electrons with opposite spin orientations. All these phenomena have been shown to originate from the existence of a single forward-propagating mode in the NLS of the junction, and argued to survive in more generic multi-band Weyl NLSs., Comment: 12 pages, 11 figures

© 2020 Elsevier Ltd Bioinspired nanofluidic devices have drawn increasing global interest due to their giant applicable potential in a wide range of fields. By mimicking biological prototype, it is expected to achieve high energy conversion efficiency and tunable ion transport. However, the low osmotic conversion efficiency, weak ion transport capability and poor mechanical performance limit practical application. We designed a class of heterogeneous membrane consisting of a support layer and a thin top layer to meet fundamental requirements. To achieve higher power generation, we incorporated metal organic framework (MOF) nanosheets (dispersed phase) into polymer matrix (continuous phase) to afford a mixed matrix top layer. This unique structure addressed the geometric restriction associated with the polymeric specie due to their limited pore accessibility. As a result, the presented membranes produced high power density of ca. 7 W m−2 and a high energy conversion efficiency of ca. 40% under a salinity gradient of 50 (0.5 M|0.01 M, NaCl). This work thus offers an insight into a new methodology in the development of a novel membrane technology for highly efficient energy conversion.

The microstructure of boron doped diamond (BDD) is the main factor affecting its degradation performance, and the type of wastewater is also a major factor. In this paper, niobium based BDD electrodes were prepared by hot filament chemical vapor deposition (HFCVD) technology at 650 °C, 750 °C, 850 °C substrate temperatures. For the three BDD electrodes with different substrate temperatures, the comparison of electrochemical performance and degradation efficiency was conducted. The results showed that with the increase of deposition temperature, the microstructure of BDD electrodes surface changed, the grain size and boron content increased, and the sp3/sp2 phase ratio also increased, which caused the electrochemical oxidation performance of the BDD electrodes improved, the color removal rate of the electrodes increased, and the energy consumption reduced. The decolorization rates of the 850 °C-BDD electrode for Reactive orange X-GN and Reactive blue 19 at 180 min were 99.79 % and 93.38 %, respectively. In addition, the degradation performance of 8 dyes by 850 °C-BDD electrode was systematically studied. Affected by the molecular structure of dye, the degradation degree of each type of dye from easy to difficult was: Fuchsin acid, Reactive red 2, Acid orange G, Alizarin red, Acid blue 92, Reactive orange X-GN, Orange II, Reactive blue 19.

Correction for ‘Bioinspired hydrogel-based nanofluidic ionic diodes: nano-confined network tuning and ion transport regulation’ by Congcong Zhu et al., Chem. Commun., 2020, 56, 8123–8126, DOI: 10.1039/D0CC01313G.

The budding yeast Saccharomyces cerevisiae remains a central position among biofuel-producing organisms. However, the gene expression regulatory networks behind the ethanol fermentation is still not fully understood. Using a static fermentation model, we have examined the ethanol yields on biomass of deletion mutants for all yeast nonessential genes encoding transcription factors and their related proteins in the yeast genome. A total of 20 (about 10%) transcription factors are identified to be regulators of ethanol production during fermentation. These transcription factors are mainly involved in cell cycling, chromatin remodeling, transcription, stress response, protein synthesis and lipid synthesis. Our data provides a basis for further understanding mechanisms regulating ethanol production in budding yeast.

Biological ion channels and ion pumps with intricate ion transport functions widely exist in living organisms and play irreplaceable roles in almost all physiological functions. Nanofluidics provides exciting opportunities to mimic these working processes, which not only helps understand ion transport in biological systems but also paves the way for the applications of artificial devices in many valuable areas. Recent progress in the engineering of smart nanofluidic systems for artificial ion channels and ion pumps is summarized. The artificial systems range from chemically and structurally diverse lipid-membrane-based nanopores to robust and scalable solid-state nanopores. A generic strategy of gate location design is proposed. The single-pore-based platform concept can be rationally extended into multichannel membrane systems and shows unprecedented potential in many application areas, such as single-molecule analysis, smart mass delivery, and energy conversion. Finally, some present underpinning issues that need to be addressed are discussed.