Rapid Adaptation of Chimonobambusa opienensis Leaves to Crown-Thinning in Giant Panda Ecological Corridor, Niba Mountain.

Leaf traits reflect the ecological strategy in heterogeneous contexts and are widely used to explore the adaption of plant species to environmental change. However, the knowledge of short-term effect of canopy management on understorey plant leaf traits is still limited. Here, we studied the short-term effect of crown-thinning on the leaf morphological traits of bamboo (Chimonobambusa opienensis), an important understorey plant and staple food for the giant panda (Ailuropoda melanoleuca) of Niba Mountain. Our treatments were two crown-thinnings (spruce plantation, CS, and deciduous broad-leaved forest, CB) and two controls (broad-leaved forest canopy, FC, and the bamboo grove of clearcutting, BC). The results showed that: the CS enhanced the annual leaf length, width, area, and thickness, CB decreased almost all annual leaf traits, and perennial leaf traits in CS and CB were the opposite. The log-transformed allometric relationships of length vs. width, biomass vs. area were significantly positive while those of specific leaf area vs. thickness were significantly negative, which varied largely in treatments and age. The leaf traits and allometric relationships suggested that the CS created a more suitable habitat for bamboo growth. This study highlighted that the understorey bamboo leaf traits could adapt the improved light environment induced by crown-thinning rapidly.

Progress and Perspective of Glass-Ceramic Solid-State Electrolytes for Lithium Batteries.

The all-solid-state lithium battery (ASSLIB) is one of the key points of future lithium battery technology development. Because solid-state electrolytes (SSEs) have higher safety performance than liquid electrolytes, and they can promote the application of Li-metal anodes to endow batteries with higher energy density. Glass-ceramic SSEs with excellent ionic conductivity and mechanical strength are one of the main focuses of SSE research. In this review paper, we discuss recent advances in the synthesis and characterization of glass-ceramic SSEs. Additionally, some discussions on the interface problems commonly found in glass-ceramic SSEs and their solutions are provided. At the end of this review, some drawbacks of glass-ceramic SSEs are summarized, and future development directions are prospected. We hope that this review paper can help the development of glass-ceramic solid-state electrolytes.

Core-shell NiS2@C encased by thin carbon layer as high-rate and durable electrode for aqueous rechargeable battery.

Nickel sulfides, as promising candidate for aqueous rechargeable battery, have aroused broad attention on account of abundant natural resources, rich phases, moderate price and high theoretical capacity. Nevertheless, tremendous volume expansion during repeated charging-discharging procedure leads to the poor rate capability and cycling stability of nickel sulfide electrodes. Therefore, in this work, core-shell NiS2@C encapsulated by thin hydrothermal carbon (HC) layer (NiS2@C/HC) has been designed and prepared without any surfactants or templates assistance, which avoid tedious process and shorten preparation cycle greatly. When matched with the treated iron powder (TIP) electrode to form NiS2@C/HC//TIP aqueous rechargeable battery, the NiS2@C/HC//TIP battery exhibits a high discharge capacity of 205.1 mAh g-1 at 1 A g-1, remarkable rate ability (176.4 mAh g-1 at 5 A g-1, about 86% capacity conversation) and superiorly durable stability (80.8 % capacity retention after 10,000 cycles at ultra-high current density of 15 A g-1). The outstanding high-rate capability and cycling stability for aqueous rechargeable battery can be ascribed to the distinct cowpea-like architecture and intrinsic properties of NiS2@C/HC. Specifically, the interior porous carbon provides a space to tolerate the volume expansion of the NiS2 nanoparticles and prevent NiS2 nanoparticles from aggregation, guaranteeing its high-rate capability. Meanwhile, the exterior HC layer is conducive to improve the electric conductivity to facilitate the electrons transfer and promote the mechanical strength of the whole active materials, ensuring its robust cycling stability.

Evaluating the Residual Stress and Its Effect on the Quasi-Static Stress in Polyethylene Pipes.

Residual stress is generated during the production process. It can significantly affect the mechanical performance of pressurized polymer pipes. In this paper, six polyethylene (PE) pipes, including three high-density PEs (HDPE) and three medium-density PEs (MDPE) provided by different suppliers, were tested using a one-slit-ring method to measure the residual stress distribution along the hoop direction. Finite element (FE) simulation and mechanical testing were also employed in an iteration process to obtain the mechanical parameters of the six PE pipes. For the same PE pipe code from different suppliers, the results show that the magnitude of the residual hoop stress can be very different, resulting in different mechanical behaviors. In addition, the results are proposed to explain the scenario that was reported previously, i.e., the different critical quasi-static stress (the time-independent stress) levels of the PE pipes with the same pipe code. Since the quasi-static stress is expected to dominate the long-term behavior of the PE pipes, it is of great importance to carefully consider the effect of the residual stress on the determination of the quasi-static stress.

Synthesis and properties of poly(1,3-dioxolane) in situ quasi-solid-state electrolytes via a rare-earth triflate catalyst.

We report a rare-earth triflate catalyst Sc(OTf)3 for the ring-opening polymerization of 1,3-dioxolane and the in situ production of a quasi-solid-state poly(1,3-dioxolane) electrolyte, which not only demonstrates a superior ionic conductivity of 1.07 mS cm-1 at room temperature, but achieves dendrite-free lithium deposition and a high Coulombic efficiency of 92.3% over 200 Li plating/striping cycles.

Oxygen-Deficient Stannic Oxide/Graphene for Ultrahigh-Performance Supercapacitors and Gas Sensors.

The metal oxides/graphene nanocomposites have great application prospects in the fields of electrochemical energy storage and gas sensing detection. However, rational synthesis of such materials with good conductivity and electrochemical activity is the topical challenge for high-performance devices. Here, SnO2/graphene nanocomposite is taken as a typical example and develops a universal synthesis method that overcome these challenges and prepares the oxygen-deficient SnO2 hollow nanospheres/graphene (r-SnO2/GN) nanocomposite with excellent performance for supercapacitors and gas sensors. The electrode r-SnO2/GN exhibits specific capacitance of 947.4 F g-1 at a current density of 2 mA cm-2 and of 640.0 F g-1 even at 20 mA cm-2, showing remarkable rate capability. For gas-sensing application, the sensor r-SnO2/GN showed good sensitivity (~13.8 under 500 ppm) and short response/recovering time toward methane gas. These performance features make r-SnO2/GN nanocomposite a promising candidate for high-performance energy storage devices and gas sensors.

Na-Ions Diffusion Impacts Supercapacitor Performance for Amaryllis-like NiCo2O4 Nanostructures.

NiCo2O4 nanomaterials with exceptional electrochemical performances are synthesized via a simple and low-cost method. The synthesized nanostructures exhibit a high specific surface area of 121.52 m2 g-1 and excellent specific capacitance of 2498.49 F g-1 at a current density of 2 A g-1, an energy density of 79 Wh kg-1, and power density of 3570 W kg-1. The remarkable cycling stability of 92.61% retention after 5000 cycles demonstrates that NiCo2O4 nanomaterials have a potential for practical application in energy storage devices. The Na+ ion diffusion (by VASP) affirms a low activation energy barrier for Na ion intercalations onto the electrode material, illuminating excellent electrochemical performances.

Thermal Properties of the Mixed n-Octadecane/Cu Nanoparticle Nanofluids during Phase Transition: A Molecular Dynamics Study.

Paraffin based nanofluids are widely used as thermal energy storage materials and hold many applications in the energy industry. In this work, equilibrium and nonequilibrium molecular dynamics simulations are employed to study the thermal properties of the mixed nanofluids of n-octadecane and Cu nanoparticles during phase transition. Four different nanofluids systems with different mass ratios between the n-octadecane and Cu nanoparticles have been studied and the results show that Cu nanoparticles can improve the thermal properties of n-octadecane. The melting point, heat capacity and thermal conductivity of the mixed systems are decreased with the increasing of the mass ratio of n-octadecane.

[Study on degradation kinetics or potassium dehydroandrographolidi succinas].

OBJECTIVE: To investigate the hydrolytic degradation of the kinetic characteristics of Potassium Dehydroandrographolidi Succinas (DAS-K) in aqueous solution. METHODS: The HPLC method was used to determine the degradation kinetic parameters of DAS-K aqueous solution at different initial concentration, different pH, different ionic strength. various temperatures and in different buffer solutions. RESULTS: DAS-K hydrolytic degradation followed first-order kinetics as measured by HPLC. From pH 8, the hydrolytic degradation rate of DAS-K markedly increased with pH. DAS-K was unstable in alkaline pH solution. The species of buffer solutions seem to have different impact on the catalytic process. The ionic strength did not have significant effect on the stability of the drug. According to the Arrhenius plot, the dependence of the decomposition on temperature was a determining factor, the activation energy was estimated to be 95.68 KJ/mol in phosphate buffer solution at pH 8 and temperature from 60 to 90 degrees C. CONCLUSION: It was found that the hydrolytic degradation of DAS-K complied with first-order kinetics. The rate of hydrolytic degradation of DAS-K depended on the pH of solution, the buffer concentration, the buffer species and the temperature. Especially, pH value was an important factor in determining the rate of the hydrolytic degradation of the drug.