Hierarchically Structured Nb_(2)O_5 Microflowers with Enhanced Capacity and Fast-Charging Capability for Flexible Planar Sodium Ion Micro-Supercapacitors

Planar Na ion micro-supercapacitors(NIMSCs) that offer both high energy density and power density are deemed to a promising class of miniaturized power sources for wearable and portable microelectron-ics. Nevertheless, the development of NIMSCs are hugely impeded by the low capacity and sluggish Na ion kinetics in the negative electrode.Herein, we demonstrate a novel carbon-coated Nb_(2)O_5 microflower with a hierarchical structure composed of vertically intercrossed and porous nanosheets, boosting Na ion storage performance. The unique structural merits, including uniform carbon coating, ultrathin nanosheets and abun-dant pores, endow the Nb_(2)O_5 microflower with highly reversible Na ion storage capacity of 245 mAh g^(-1) at 0.25 C and excellent rate capability.Benefiting from high capacity and fast charging of Nb_(2)O_5 microflower, the planar NIMSCs consisted of Nb_(2)O_5 negative electrode and activated car-bon positive electrode deliver high areal energy density of 60.7 μWh cm^(-2),considerable voltage window of 3.5 V and extraordinary cyclability. Therefore, this work exploits a structural design strategy towards electrode materials for application in NIMSCs, holding great promise for flexible microelectronics.

Manipulating Horizontal Zn Deposition with Graphene Interpenetrated Zn Hybrid Foils for Dendrite-Free Aqueous Zinc Ion Batteries

Aqueous zinc ion batteries(ZIBs)with intrinsic safety have great potentials in portable devices,but suffer from limited cycling life mainly caused by serious dendrite growth and unavoidable side reactions of Zn anodes.Herein,graphene interpenetrated Zn(GiZn)hybrid foils are developed for dendrite-free and long-term Zn anodes for high-performance ZIBs.The GiZn anode is prepared by interfacial assembly of reduced graphene oxide(rGO)on the skeletons of zinc foams,followed by mechanical compression into hybrid foils and drying process.The presence of the rGO nanosheets in the GiZn hybrid foils provides abundant zincophilic sites to induce horizontal Zn deposition for Zn metal anodes without the growth of dendrites.Meanwhile,the uniform distribution of rGO nanosheets endows the hybrid foils with superior conductivity and wetting ability with electrolytes for reduced interfacial resistances.As a result,GiZn-based symmetric cells exhibit a small voltage hysteresis of 30.4 mV and remarkable areal capacity of 30 mAh cm^(-2)at 0.5 mA cm^(-2).Further,GiZn anodes also enable the corresponding aqueous Zn||MnO_(2)batteries with high capacity of 168.5 mAh g^(-1)at 8 C,superior to the counterpart with pure Zn foil anodes(72.7 mAh g^(-1)).Therefore,GiZn hybrid foil anodes will shed light on the rational construction of 2D material-interpenetrated Zn hybrid foil anodes for high-performance ZIBs.

Reducing children’s exposure to di(2-ethylhexyl)phthalate in homes and kindergartens in China:Impact on lifetime cancer risks and burden of disease

Exposure to di(2-ethylhexyl)phthalate(DEHP)in the indoor environment has been linked with significant health risks for Chinese children.Multi-phase DEHP concentrations in Chinese residences and kindergartens were estimated using a mass balance model based on the current baseline condition and control strategies(i.e.,increasing ventilation rate,reducing area of sources,using mechanical ventilation systems,and using portable air cleaners).The health benefits of each control strategy were quantified as the reduction in lifetime cancer risks(LCR)and burden of disease(BoD).In the current situation,the mean LCR and disability-adjusted life years(DALY)number attributable to indoor DEHP exposure for Chinese children were around 6.0×10^(−6) and 155 thousand,respectively.The mean LCR and DALY might be reduced by 25%-54%and 16%-40%,respectively,by increasing air exchange rates by 100%,reducing the use of source materials by two-thirds or deploying commercial air cleaners in naturally ventilated buildings.Meanwhile,avoidable DALYs could result in a reduction of mean economic losses of 2.2-5.3 billion RMB.Mechanical ventilation systems with filtration units may not be helpful for reducing children’s health risks.House-specific and tailor-made control measures are critical in lowering indoor exposure to DEHP to promote sustainable buildings and children’s health in China.

Hybrid ion/electron interfacial regulation stabilizes the cobalt/oxygen redox of ultrahigh-voltage lithium cobalt oxide for fast-charging cyclability

High-voltage and fast-charging LiCoO_(2)(LCO)is key to high-energy/power-density Li-ion batteries.However,unstable surface structure and unfavorable electronic/ionic conductivity severely hinder its high-voltage fast-charging cyclability.Here,we construct a Li/Na-B-Mg-Si-O-F-rich mixed ion/electron interface network on the 4.65 V LCO electrode to enhance its rate capability and long-term cycling stability.Specifically,the resulting artificial hybrid conductive network enhances the reversible conversion of Co^(3+)/^(4+)/O_(2)/nredox by the interfacial ion–electron cooperation and suppresses interface side reactions,inducing an ultrathin yet compact cathode electrolyte interphase.Simultaneously,the derived near-surface Na+/Mg2+/Si^(4+)-pillared local intercalation structure greatly promotes the Li^(+)diffusion around the 4.55 V phase transition and stabilizes the cathode interface.Finally,excellent 3 C(1 C=274 mA g1)fast charging performance is demonstrated with 73.8%capacity retention over 1000 cycles.Our findings shed new insights to the fundamental mechanism of interfacial ion/electron synergy in stabilizing and enhancing fast-charging cathode materials.

Coupled planning of water resources and agricultural land-use based on an inexact-stochastic programming model

Water resources are fundamental for support of regional development. Effective planning can facilitate sustainable management of water resources to balance socioeconomic development and water conservation. In this research, coupled planning of water resources and agricultural land use was undertaken through the develop- ment of an inexact-stochastic programming approach. Such an inexact modeling approach was the integration of interval linear programming and chance-constraint pro- gramming methods. It was employed to successfully tackle uncertainty in the form of interval numbers and probabil- istic distributions existing in water resource systems. Then it was applied to a typical regional water resource system for demonstrating its applicability and validity through generating efficient system solutions. Based on the process of modeling formulation and result analysis, the developed model could be used for helping identify optimal water resource utilization patterns and the corresponding agri- cultural land-use schemes in more, a number of decision three sub-regions. Further- alternatives were generated under multiple water-supply conditions, which could help decision makers identify desired management policies.

Can the Shanghai LNG Price Index indicate Chinese market?An econometric investigation using price discovery theory

China became the world's second largest liquefied natural gas(LNG)importer in 2018 but has faced extremely high import costs due to a lack of bargaining power.Assessments of the Shanghai LNG Price Index,first released in 2015,are vital for improving the understanding of these cost dynamics.This paper,using the LNG price index data from the Shanghai Petroleum and Gas Exchange(SHPGX)coupled with domestic and international LNG prices from July 1,2015 to December 31,2018,estimates several econometric models to evaluate the long-term and short-term equilibriums of the Shanghai LNG Price Index,the responses to market information shocks and the leading or lagging relationships with LNG and alternative energy prices from other agencies.The results show that the LNG price index of the SHPGX has already exhibited a long-term equilibrium and short-term adjustment mechanisms to reflect the average price level and market movements,but the market information transparency and price discovery efficiency of the index are still inadequate.China's LNG market is still relatively independent of other natural gas markets,and marketization reforms are under way in China.The influence of the SHPGX LNG price index on the trading decisions of market participants is expected to improve with further development of China's LNG reforms,the formation of a natural gas entry-exit system,and the increasing liquidity of the hub.

Modeled exposure to phthalates via inhalation and dermal pathway in children's sleeping environment: A preliminary study and its implications

In this study,exposure to phthalates during children’s sleeping time was evaluated based on a mechanistic model.Airborne phase-specific concentrations in this model were estimated taking into account kinetic partitioning,particle dynamics and time-varying ventilation.Exposure pathways considered were inhalation exposure to airborne phases,dermal absorption from "air-to-skin" transport and direct contact.By taking di(n-butyl)phthalate(DnBP)and bis(2-ethylhexyl)phthalate(DEHP)as two representative pollutants,inhalation exposure accounted for>90%when children wore clean pajamas before going to bed.Dermal uptake significantly increased when children's pajamas had absorbed DnBP before putting them on,whereas dermal uptake of DEHP was relatively lower and insensitive to the condition of clothing.Increasing air exchange rate at night and keeping clothes cleaner were effective for reducing children's exposures during sleeping period.Further studies are necessary taking into account source-proximity effect,particle emissions and refined dermal exposure routes.

Difluorocarbene-enabled access to 1,3-oxazin- 6-ones from enamides

1,3-Oxazin-6-ones as important structural scaffolds widely exist in many bioactive or therapeutic agents.The development of straightforward synthetic approaches to access 1,3-oxazin-6-ones is highly desirable for studying their fundamental properties and applications.