Phase Separation Derived Core/Shell Structured Cu11 V6 O26 /V2 O5 Microspheres: First Synthesis and Excellent Lithium-Ion Anode Performance with Outstanding Capacity Self-Restoration.

Novel amorphous vanadium oxide coated copper vanadium oxide (Cu11 V6 O26 /V2 O5 ) microspheres with 3D hierarchical architecture have been successfully prepared via a microwave-assisted solution method and subsequent annealing induced phase separation process. Pure Cu11 V6 O26 microspheres without V2 O5 coating are also obtained by an H2 O2 solution dissolving treatment. When evaluated as an anode material for lithium-ion batteries (LIBs), the as-synthesized hybrid exhibits large reversible capacity, excellent rate capability, and outstanding capacity self-recovery. Under the condition of high current density of 1 A g-1 , the 3D hierarchical Cu11 V6 O26 /V2 O5 hybrid maintains a reversible capacity of ≈1110 mA h g-1 . Combined electrochemical analysis and high-resolution transmission electron microscopy observation during cycling reveals that the amorphous V2 O5 coating plays an important role on enhancing the electrochemical performances and capacity self-recovery, which provides an active amorphous protective layer and abundant grain interfaces for efficient inserting and extracting of Li-ion. As a result, this new copper vanadium oxide hybrid is proposed as a promising anode material for LIBs.

Soil carbon sequestration due to post-Soviet cropland abandonment: estimates from a large-scale soil organic carbon field inventory.

The break-up of the Soviet Union in 1991 triggered cropland abandonment on a continental scale, which in turn led to carbon accumulation on abandoned land across Eurasia. Previous studies have estimated carbon accumulation rates across Russia based on large-scale modelling. Studies that assess carbon sequestration on abandoned land based on robust field sampling are rare. We investigated soil organic carbon (SOC) stocks using a randomized sampling design along a climatic gradient from forest steppe to Sub-Taiga in Western Siberia (Tyumen Province). In total, SOC contents were sampled on 470 plots across different soil and land-use types. The effect of land use on changes in SOC stock was evaluated, and carbon sequestration rates were calculated for different age stages of abandoned cropland. While land-use type had an effect on carbon accumulation in the topsoil (0-5 cm), no independent land-use effects were found for deeper SOC stocks. Topsoil carbon stocks of grasslands and forests were significantly higher than those of soils managed for crops and under abandoned cropland. SOC increased significantly with time since abandonment. The average carbon sequestration rate for soils of abandoned cropland was 0.66 Mg C ha-1  yr-1 (1-20 years old, 0-5 cm soil depth), which is at the lower end of published estimates for Russia and Siberia. There was a tendency towards SOC saturation on abandoned land as sequestration rates were much higher for recently abandoned (1-10 years old, 1.04 Mg C ha-1  yr-1 ) compared to earlier abandoned crop fields (11-20 years old, 0.26 Mg C ha-1  yr-1 ). Our study confirms the global significance of abandoned cropland in Russia for carbon sequestration. Our findings also suggest that robust regional surveys based on a large number of samples advance model-based continent-wide SOC prediction.

Improvement in Cohesive Properties of Adhesion Systems Using Movable Cross-Linked Materials with Stress Relaxation Properties.

A strong, tough, and stable adhesion system used in various environments must be developed. A long-lasting adhesion system should effectively perform in the following five aspects: adhesion strength, toughness, energy dissipation property, self-restoration property, and creep resistance property. However, these properties are difficult to balance using conventional adhesives. Here, a new topological adhesion system using single-movable cross-network (SC) materials [SC(DMAAm) Adh] was designed. 3-(Trimethoxysilyl) propyl acrylate was used as the anchor, N,N-dimethyl acrylamide (DMAAm) was used as the main chain monomer, and γ-cyclodextrin (γ-CD) units acted as movable cross-links. The movable cross-links provided SC(DMAAm) Adh with energy dissipation properties, thereby improving its toughness. The γ-CD units also acted as bulky stoppers that provided a high adhesion strength and self-restoration properties. Moreover, the combination of the movable cross-links and bulky stoppers provided creep resistance to SC(DMAAm) Adh. The performance of the adhesion systems under different mobilities of the polymer chains was examined by adjusting the water content. In proper water-containing states, all mechanical properties of SC(DMAAm) Adh were better than those of the adhesion systems using homopolymers [P(DMAAm) Adh] and polymers with covalent cross-linking points [CP(DMAAm) Adh].

Soil moisture evidence of self-restoration in coal mining subsidence area of Shendong Mining area: Cognition based on stable isotopes.

The Shendong mining area is the largest coal production base in China. However, the area is dry and water scarce, and the ecological environment is fragile. Large scale mining of shallow and thick coal seam in mining area may affect surface moisture and threaten surface ecological security. In order to understand the change of soil moisture in subsidence area. The evaporation loss rate of undisturbed and subsidence soil in mining area was estimated by using water stable isotope technique. The soil particle size and moisture of undisturbed and subsidence soil were compared. The results showed that the soil particle size did not change significantly in the subsidence area, but the continuity of soil structure changed. The evaporation loss rate of soil in subsidence area is about 15 % lower than that of undisturbed soil, and the soil moisture of soil in subsidence area is about 10 % higher than that of undisturbed soil. Further, the Craig-Gordon model is more accurate than the Rayleigh model in estimating the evaporation loss of soil moisture. Our work showed that the soil structure of coal mining subsidence area becomes much looser and the loose cover formed by the surface soil is the main reason for the reduction of soil moisture evaporation. The significant increase of soil moisture will be beneficial to plant recovery and growth, and lay a water foundation for ecological self-restoration in subsidence area. This study is helpful to understand the influence of coal mining subsidence on soil and surface hydrology in arid and semi-arid areas, and has important significance for optimizing and improving the ecological reclamation model of mining areas in western China.

Performance Assessment of Self-Healing Polymer-Modified Bitumens by Evaluating the Suitability of Current Failure Definition, Failure Criterion, and Fatigue-Restoration Criteria.

Fatigue cracking is a common form of flexible pavement distress, which generally starts and spreads through bitumen. To address this issue, self-healing elastomer (SHE) modified bitumens were elaborated to assess whether these novel materials can overcome the neat asphalt (NA) fatigue performance and whether the current failure definition, failure criterion, and fatigue-restoration criteria can fit their performance. All bitumens were subjected to short-term and long-term aging. Linear amplitude sweep (LAS) test, LAS with rest period (LASH), and simplified viscoelastic-continuum-damage (S-VECD) model were utilized to appraise the behavior of the mentioned bitumens. The results showed that maximum stored pseudo-strain energy (PSE) and tau (τ) × N (number of loading cycles) failure definitions exhibited high efficiency to accommodate the fatigue life of NA and SHE-modified bitumens. Both failure criteria identified that SHE-modified bitumen (containing 1% of SHE) showed the highest increment of fatigue performance (67.1%) concerning NA. The failure criterion based on total released PSE, in terms of the area under the released PSE curve, was the only failure concept with high efficiency (R2 up to 0.999) to predict asphalt binder fatigue life. As well, the current framework to evaluate bitumen self-restoration failed to fully accommodate asphalt binder behavior, because bitumen with higher restoration could not exhibit greater fatigue performance. Consequently, a new procedure to assess this property including fatigue behavior was proposed, showing consistent results, and confirming that SHE-modified bitumen (containing 1% of SHE) exhibited the highest increment of fatigue performance (154.02%) after application of the rest period. Hence, the optimum SHE content in NA was 1%. Furthermore, it was found that a greater number of loading cycles to failure (Nf) did not ensure better fatigue performance and stored PSE influenced the bitumen fatigue behavior.

A Computational Framework for Controlling the Self-Restorative Brain Based on the Free Energy and Degeneracy Principles.

The brain is a non-linear dynamical system with a self-restoration process, which protects itself from external damage but is often a bottleneck for clinical treatment. To treat the brain to induce the desired functionality, formulation of a self-restoration process is necessary for optimal brain control. This study proposes a computational model for the brain's self-restoration process following the free-energy and degeneracy principles. Based on this model, a computational framework for brain control is established. We posited that the pre-treatment brain circuit has long been configured in response to the environmental (the other neural populations') demands on the circuit. Since the demands persist even after treatment, the treated circuit's response to the demand may gradually approximate the pre-treatment functionality. In this framework, an energy landscape of regional activities, estimated from resting-state endogenous activities by a pairwise maximum entropy model, is used to represent the pre-treatment functionality. The approximation of the pre-treatment functionality occurs via reconfiguration of interactions among neural populations within the treated circuit. To establish the current framework's construct validity, we conducted various simulations. The simulations suggested that brain control should include the self-restoration process, without which the treatment was not optimal. We also presented simulations for optimizing repetitive treatments and optimal timing of the treatment. These results suggest a plausibility of the current framework in controlling the non-linear dynamical brain with a self-restoration process.

Effect of freshwater inflow on self-restoration of macrobenthic diversity in seaward intertidal wetlands influenced by reclamation projects in the Yangtze estuary, China.

The Yangtze estuary is considered as an important eco-region of China, but it has been heavily disturbed by reclamation projects. We evaluated the effect of freshwater inflow on the self-restoration of macrobenthic diversity in 3-year-old vegetated, gravel, and mudflat habitats of reclaimed seaward intertidal wetlands. There was a significant self-restoration of species richness and diversity in vegetated and gravel habitats with no inflow of freshwater, but there were no significant changes in species diversity in three habitats subjected to freshwater inflow. Significant changes in community structures of macrobenthos occurred in vegetated and gravel habitats from pre- to post-restoration. Analysis of benthic health showed that gravel habitats were under moderate to high levels of disturbance in pre-restoration period. In contrast, there tended to be no evidence of disturbance in vegetated and mudflat habitats during two investigations. Restoration of macrobenthos is best achieved in vegetated habitats with on inflow of freshwater.

Loss and self-restoration of macrobenthic diversity in reclamation habitats of estuarine islands in Yangtze Estuary, China.

In this study, macrobenthic diversity data were collected from intertidal habitats of island wetlands in Yangtze Estuary before and after reclamation. Three survey regions based on habitat features were investigated: protected region, normal region, and self-restored region. The pattern of diversity variation showed a sharp decrease in reclamation sites and an obvious increase in vegetated sites of the self-restored region before and after reclamation. A declining trend in habitat health was observed in reclamation sites, but the degree of perturbation was relatively weaker in protected region than in normal region. The vegetated site showed a better self-restoration of biodiversity than the bald site. These results suggest that reclamation may have a negative influence on biodiversity and habitat health status in the intertidal wetland. Also, there is a possibility of self-restoration in tidal flats disturbed by reclamation and the resistance effect in nature reserve may reduce the disturbances resulting from reclamation.