Upcycling of phosphogypsum waste for efficient zinc-ion batteries

Zinc metal is a promising anode material for next-generation aqueous batteries,but its practical application is limited by the formation of zinc dendrite.To prevent zinc dendrite growth,various Zn^(2+)-conducting but water-isolating solid-electrolyte interphase(SEI)films have been developed,however,the required high-purity chemical materials are extremely expensive.In this work,phosphogypsum(PG),an industrial byproduct produced from the phosphoric acid industry,is employed as a multifunctional protective layer to navigate uniform zinc deposition.Theoretical and experimental results demonstrate that PG-derived CaSO_(4)2H_(2)O can act as an artificial SEI layer to provide fast channels for Zn^(2+)transport.Moreover,CaSO_(4)2H_(2)O could release calcium ions(Ca^(2+))due to its relatively high Kspvalue,which have a higher binding energy than that of Zn^(2+)on the Zn surface,thus preferentially adsorbing to the tips of the protuberances to force zinc ions to nucleate at inert region.As a result,the Zn@PG anode achieves a high Coulombic efficiency of 99.5%during 500 cycles and long-time stability over 1000 hours at 1 m A cm^(-2).Our findings will not only construct a low-cost artificial SEI film for practical metal batteries,but also achieve a high-value utilization of phosphogypsum waste.

聚乳酸及其共聚物单丝的体外降解性能

通过熔融挤出-热拉伸分别制备了PLLA、PLCL 95/5和PLGC 89/8/3单丝。经环氧乙烷灭菌处理后的3种单丝置于37℃的磷酸盐缓冲溶液(pH=7.4±0.2)中进行180 d的体外降解。采用失重率分析、扫描电镜、凝胶渗透色谱分析、差示扫描量热分析、X射线衍射及力学性能测试等方法分别对3种单丝的降解性能进行了研究。结果表明,丙交酯单体含量对PLLA及其共聚物的降解性能有较大的影响。PLLA单丝经过180 d的体外降解,单丝的表面形态和失重率几乎不变,力学性能缓慢降低;对于PLCL 95/5单丝,在降解前60 d,相对分子质量和熔点(T_m)明显下降,力学性能基本丧失;而PLGC 89/8/3单丝降解最快,在降解前30 d,相对分子质量和T_m显著降低,力学性能完全消失。根据降解的一级动力学模型计算出PLCL 95/5单丝降解速率比PLLA单丝快5.0倍,PLGC 89/8/3单丝的降解速率比PLLA快8.0倍。

Catalytic Oxidation of Dimethyl Ether to Dimethoxymethane over Cs Modified H_3PW_(12)O_(40)/SiO_2 Catalysts

The attractive utilization route for one-step catalytic oxidation of dimethyl ether to dimethoxymethane was successfully carried out over the H3PW12O40（40%）/SiO2 catalyst, modified by Cs, K, Ni, and V. The Cs modification of H3PW12O40（40%）/SiO2 gave the most promising result of 20% dimethyl ether conversion and 34.8% dimethoxymethane selectivity. Dimethoxymethane could be synthe- sized via methoxy groups decomposed from dimethyl ether through the synergistic effect between the acid sites and the redox sites of Cs modified H3PW12O40（40%）/SiO2.

Community Workers’Social Support and Sleep Quality during the Coronavirus Disease 2019(COVID-19):A Moderated Mediation Model

To explore the relationship between social support and sleep quality of community workers in Wuhan during the coronavirus disease 2019(the COVID-19 infection epidemic),this research constructed a mediating effect model to explore the mediating psychological mechanism of social support influencing sleep quality of front-line community workers.A total of 500 front-line community workers in Wuhan were investigated.We used the perceived social support scale(PSSS),the Connor-Davidson Resilience Scale(CD-RISC),the perceived stress scale(PSS),and the Pittsburgh sleep quality index(PSQI)to measure social support,psychological resilience,perceived stress and sleep quality.Specifically,the higher the PSQI,the worse the sleep quality.Pearson correlation structural equation model was used to analyze the relationship between these factors.The results showed that:(1)There was a significant negative correlation between social support,psychological resilience,and perceived stress of community workers and PSQI,that means,the higher the level of social support,psychological resilience,and perceived stress,the higher the sleep quality.(2)Social support positively predicted psychological resilience and perceived stress,and perceived stress negatively predicted PSQI.(3)Social support can affect sleep quality through the mediating role of psychological resilience and perceived stress,and the mediating role includes two paths:the single mediating role of perceived stress and the chain mediating role of psychological resilience-perceived stress.(4)Gender moderates the relation-ship between social support and perceived stress,and the influence of social support on perceived stress of women is higher than that of men.Gender moderates the relationship between psychological resilience and PSQI,and only women’s psychological resilience had a negatively predictive effect on PSQI,while men did not,which means that psychological resilience of female frontline community workers can positively predict sleep quality.This research reveals the relationship between social support and sleep quality and its mechanism and verifies that social support can indirectly affect physical health through psychological resilience and perceived stress.It provides reference suggestions and intervention guidance for improving the sleep quality of community workers.

耕作模式对河西绿洲灌区夏玉米农田土壤呼吸的影响

以河西绿洲灌区夏玉米农田土壤为研究对象,设置免耕(NT)和传统耕作(CT)两种耕作方式,玉米间作小麦(W/M)、玉米小麦轮作(W→M)和麦后插播冬油菜还田玉米轮作(W-G→M)3种种植模式,探讨河西绿洲灌区不同耕作模式对夏玉米农田土壤呼吸变化特征的影响。测定夏玉米不同生育时期土壤呼吸速率、土壤温度和土壤含水量。结果表明:河西绿洲灌区不同耕作模式下夏玉米农田土壤呼吸有着明显的单峰型日变化,且峰值出现在15:00左右,玉米生育期峰值出现在拔节期(6月上旬)。土壤呼吸速率与土壤温度、土壤含水量均显著正相关,且土壤呼吸速率日变化主要受5 cm土壤温度影响。6种耕作模式的土壤呼吸的温度敏感性Q10值为1.60~2.70,免耕均高于传统耕作,且依次为NT W→M>NT W/M>NT W-G→M>CT W-G→M>CT W→M>CT W/M。河西绿洲灌区不同耕作模式下夏玉米农田土壤呼吸不仅受土壤温度影响,还受土壤含水量的影响。

Bamboo‑Inspired Gasotransmitter Microfibres for Wound Healing

Diabetic wounds have become a major clinical problem that cannot be ignored.Gases,such as hydrogen sulphide(H_(2)S),have demonstrated value in inducing angiogenesis and accelerating wound healing,while their effective delivery is still challenging.Here,inspired by the continuous-independent hollow structure of bamboo,we propose novel gasotransmitter microfibres with septal H_(2)S bubbles using microfluidic spinning for diabetic wound healing.Benefitting from the exact control of microfluidics,gasotransmitter microfibres with different bubble sizes and morphologies could be generated successfully and continuously.Under the dual effects of drugs in the shell and gas in the core,the wound healing process could be accelerated.Furthermore,the controllable release of drugs could be achieved by adding responsive materials into the microfiber shell,which would promote continuous effects of contents on demand.Based on in vitro and in vivo stud-ies,we have proven that these gasotransmitter microfibres have a positive impact on inducing angiogenesis and promoting cell proliferation during wound healing.Thus,it is believed that the bamboo-inspired gasotransmitter microfibres will have important value in gasotransmitter research and clinical applications.

Efficient anion immobilization enabled by structurally controllable halloysite for dendrite-free sodium metal anode

Sodium metal has shown great potential as an inexpensive anode for rechargeable batteries. However, the growth of sodium dendrites continues to hinder the commercialization of Na metal batteries. Herein, an effective strategy using anion-anchoring halloysite nanotube(HNT) coating was proven to prevent the diffusion of anions and trigger uniform Na deposition. Through theoretical calculation, a model of active site of fixed anions exposed from HNTs after acid activation was established for the first time, revealing that Si–Al sites are effective active site of acid-activated HNTs. Furthermore, HNTs with strong and effective adsorption capacity for anions were obtained by controlling the structure of HNTs to regulate the exposure of Si–Al sites. The strong interaction between sites of acid-activated HNTs and the SO_(3)CF_(3)^(-) anion effectively promotes the dissociation of sodium salts, the release of Na^(+) and subsequent migration. As a result, HNTs acid activation for 4 h shows a steady sodium deposition process and displays high Coulombic efficiency in half cell, long cycle life in symmetric cell and full cell. This work provides a basic theoretical basis for the design of nanoclay with abundant and effective active site to fix anions for dendritic free metal batteries.

Crystalline and amorphous Mn0_(2)cathodes with open framework enable high-performance aqueous zinc-ion batteries

Currently,δ-Mn0_(2)is one of the popularly studied cathode materials for aqueous zinc-ion batteries(ZIBs)but impeded by the sluggish kinetics of Zn^(2+)and the Mn cathode dissolution.Here,we report our discovery in the study of crystalline/amorphous Mn0_(2)(disordered Mn0_(2)),prepared by a simple redox reaction in the order/disorder engineering.This disordered Mn0_(2)cathode material,having open framework with more active sites and more stable structure,shows improved electrochemical performance in 2 mol L^(-1)ZnSO_(4)/0.1 mol L^(-1)MnS0_(4)aqueous electrolyte.It delivers an ultrahigh discharge specific capacity of 636 mA·h·g^(-1)at 0.1 A·g^(-1)and remains a large discharge capacity of 216 mA·h·g^(-1)even at a high current density of 1 A·g^(-1)after 400 cycles.Hence disordered Mn0_(2)could be a promising cathode material for aqueous ZIBs.The storage mechanism of the disordered Mn0_(2)electrode is also systematically investigated by structural and morphological examinations of ex situ,ultimately proving that the mechanism is the same as that of the δ-Mn0_(2)electrode.This work may pave the way for the possibility of using the order/disorder engineering to introduce novel properties in electrode materials for high-performance aqueous ZIBs.

Generating non-jumps from a known one

Let r≥2 be an integer.The real numberα∈[0,1)is a jump for r if there exists a constant c>0 such that for any?>0 and any integer m≥r,there exists an integer n_0(ε,m)satisfying any r-uniform graph with n≥n_0(ε,m)vertices and density at leastα+?contains a subgraph with m vertices and density at leastα+c.A result of Erd?s and Simonovits(1966)and Erdos and Stone(1946)implies that everyα∈[0,1)is a jump for r=2.Erdos(1964)asked whether the same is true for r≥3.Frankl and Rodl(1984)gave a negative answer by showing that1-1/(ε^(r-1))is not a jump for r if r 3 and l>2r.After that,more non-jumps are found by using a method of Frankl and R?dl(1984).Motivated by an idea of Liu and Pikhurko(2023),in this paper,we show a method to construct maps f:[0,1)→[0,1)that preserve non-jumps,i.e.,ifαis a non-jump for r given by the method of Frankl and Rodl(1984),then f(α)is also a non-jump for r.We use these maps to study hypergraph Turán densities and answer a question posed by Grosu(2016).