Bio-Based Waterborne Poly(Vanillin-Butyl Acrylate)/MXene Coatings for Leather with Desired Warmth Retention and Antibacterial Properties

This study presents a solvent-free,facile synthesis of a bio-based green antibacterial agent and aromatic monomer methacrylated vanillin(MV)using vanillin.The resulting MV not only imparted antibacterial properties to coatings layered on leather,but could also be employed as a green alternative to petroleum-based carcinogen styrene(St).Herein,MV was copolymerized with butyl acrylate(BA)to obtain waterborne bio-based P(MV-BA)miniemulsion via miniemulsion polymerization.Subsequently,MXene nanosheets with excellent photothermal conversion performance and antibacterial properties,were introduced into the P(MV-BA)miniemulsion by ultrasonic dispersion.During the gradual solidification of P(MV-BA)/MXene nanocomposite miniemulsion on the leather surface,MXene gradually migrated to the surface of leather coatings due to the cavitation effect of ultrasonication and amphiphilicity of MXene,which prompted its full exposure to light and bacteria,exerting the maximum photothermal conversion efficiency and significant antibacterial efficacy.In particular,when the dosage of MXene nanosheets was 1.4 wt%,the surface temperature of P(MV-BA)/MXene nanocomposite miniemulsioncoated leather(PML)increased by about 15℃ in an outdoor environment during winter,and the antibacterial rate against Escherichia coli and Staphylococcus aureus was nearly 100%under the simulated sunlight treatment for 30 min.Moreover,the introduction of MXene nanosheets increased the air permeability,water vapor permeability,and thermal stability of these coatings.This study provides a new insight into the preparation of novel,green,and waterborne bio-based nanocomposite coatings for leather,with desired warmth retention and antibacterial properties.It can not only realize zerocarbon heating based on sunlight in winter,reducing the use of fossil fuels and greenhouse gas emissions,but also improve ability to fight off invasion by harmful bacteria,viruses,and other microorganisms.

RO_(x) Budgets and O_(3) Formation during Summertime at Xianghe Suburban Site in the North China Plain

Photochemical smog characterized by high concentrations of ozone(O_(3)) is a serious air pollution issue in the North China Plain(NCP)region,especially in summer and autumn.For this study,measurements of O_(3),nitrogen oxides(NO_(x)),volatile organic compounds(VOCs),carbon monoxide(CO),nitrous acid(HONO),and a number of key physical parameters were taken at a suburban site,Xianghe,in the NCP region during the summer of 2018 in order to better understand the photochemical processes leading to O_(3)formation and find an optimal way to control O_(3)pollution.Here,the radical chemistry and O_(3)photochemical budget based on measurement data from 1−23 July using a chemical box model is investigated.The daytime(0600−1800 LST)average production rate of the primary radicals referred to as RO_(x)(OH+HO2+RO2)is 3.9 ppbv h−1.HONO photolysis is the largest primary RO_(x)source(41%).Reaction of NO2+OH is the largest contributor to radical termination(41%),followed by reactions of RO2+NO2(26%).The average diurnal maximum O_(3)production and loss rates are 32.9 ppbv h−1 and 4.3 ppbv h−1,respectively.Sensitivity tests without the HONO constraint lead to decreases in daytime average primary RO_(x)production by 55%and O_(3)photochemical production by 42%,highlighting the importance of accurate HONO measurements when quantifying the RO_(x)budget and O_(3)photochemical production.Considering heterogeneous reactions of trace gases and radicals on aerosols,aerosol uptake of HO2 contributes 11%to RO_(x)sink,and the daytime average O_(3)photochemical production decreases by 14%.The O_(3)-NO_(x)-VOCs sensitivity shows that the O_(3)production at Xianghe during the investigation period is mainly controlled by VOCs.

Close-loop recyclable and flexible halide perovskite@wool keratin sensor with piezoelectric property

Halide perovskites with excellent piezoelectric properties,but their poor stability hinders their largescale application.Herein,a sandwich-structured halide perovskite flexible sensor with good stability was developed according to a three-step procedure as follows:(ⅰ) in-situ growth of wool keratinCsPbBr_(3)(WK-CsPbBr_(3)) using wool keratin in interfacial passivation and coating,(ⅱ) electrospinning of a wool keratin-CsPbBr_(3)/polyacrylonitrile(WCP) nanofiber film,and(ⅲ) coating of the WCP nanofiber with polydimethylsiloxane(PDMS) to obtain a sensor(WCPP).The sensor could generate a piezoelectric voltage of 7.8 V at a pressure of 6 kPa in the stages of pressing and releasing,and the output characteristics did not decline even after 10,000 cycles.Compared to the 4-month stability of the perovskite sensor,WCPP sensor exhibited the output performance even after 16 months,which indicated that wool keratin as a multidentate improved the stability of the halide perovskite.Additionally,the sensor displayed a self-cleaning property and could also light up 14 commercial LEDs.The close-loop recycling of the lead halide perovskite was achieved by dissolving the WCP nanofiber film in DMF and then reelectrospinning.Therefore,the method proposed is a step forward for achieving the commercialization of WK-CsPbBr_(3) and providing new avenues for further utilization of wool waste.

Recent Enhanced Deep Troposphere-to-Stratosphere Air Mass Transport Accompanying the Weakening Asian Monsoon

The Asian monsoon(AM) region is a well-known region with prevailing stratosphere–troposphere exchange(STE).However,how the STE across this region changes with the weakening AM remains unclear.Here,we particularly diagnose the air mass transport between the planetary boundary layer(PBL) and the stratosphere over the AM region during 1992–2017 using the Lagrangian particle dispersion model FLEXPART based on the ERA-Interim reanalysis data.The results show that both the downward and upward deep STEs exhibit a detectable increasing trend,while the latter,namely,the deep troposphere-to-stratosphere transport(DTST),is relatively more significant.Further analysis reveals that the long-term trend of DTST over the AM region could be partly attributed to changes in the Pacific Walker circulation and the air temperature(especially at upper levels).Additionally,it is found that DTST increases markedly over the tropical oceanic regions,while the increasing DTST into the stratosphere can be attributed to the enhanced air masses originated from the PBL over the terrestrial regions,where large amounts of pollutant emissions occur.The results imply that the influence of the DTST on the chemical composition and the climate of the stratosphere over the AM region is expected to become increasingly important,and is thereby of relevance to climate projection in an evolving climate.

Ultra-low reflection electromagnetic interference shielding nanofiber film with effective solar harvesting and self-cleaning

It is urgent to develop low-reflection electromagnetic interference shielding material to shield electromagnetic waves(EMW)and reduce their secondary radiation pollution.Herein,an electromagnetic interference shielding nanofiber film is composed of ZnO and carbon nanofiber(CNF)via electrospinning and carbonization approachs,and subsequently coating perfuorooctyltriethoxysilane as a protective layer.On the one hand,ZnO coated by porous carbon,which is derived from ZIF-8,endows the nanofiber film low reflection property through optimizing impedance matching between free space and the nanofiber film.On the other hand,the nanofiber film possesses high electromagnetic interference shielding efficiency,which is beneficial by excellent electrical conductivity of CNF derived from waste leather scraps.Furthermore,the nanofiber film involves abundant interface,which contributes to high interfacial polarization loss.Thus,the nanofiber film with a thickness of 250 pm has electrical conductivity of 53 S/m and shielding efficiency of 50 dB.The reflection coefficient of the nanofiber film is inferior to 0.4 indicates that most of EMW are absorbed inside the materials and the nanofiber film is effective in reducing secondary radiation contamination of electromagnetic waves.Fortunately,the nanofiber film exhibits outstanding solar harvesting performance(106℃at 1 sun density)and good self-cleaning performance,which ensure that the nanofiber film can work in harsh environments.This work supplies a credible reference for fabricating low-reflection electromagnetic shielding nanofiber film to reduce secondary radiation pollution and facilitates the upcycling of waste leather scraps.

聚合物/铈掺杂纳米氧化锌复合材料的制备及性能

通过原位法将铈掺杂纳米氧化锌(Ce-ZnO)引入二甲基二烯丙基氯化铵(DMDAAC)与α-甲基丙烯酸(MAA)的共聚体系中,制备了P(DMDAAC-MAA)/(Ce-ZnO)复合材料。X射线衍射、红外光谱与透射电镜结果表明,复合材料形成了一种均匀的球型花状结构。将不同Ce-ZnO用量的复合材料应用于制革工艺中,考察了坯革的抗菌防霉性能与力学性能。应用结果表明,当Ce-ZnO用量为1.8%时,应用P(DMDAAC-MAA)/(Ce-ZnO)复合材料后坯革具有良好的抗菌性能以及较优的力学性能,但基本无防霉性能;结合扫描电镜与能谱分析结果可知,复合材料在坯革中均匀分散。

Preparation and Properties of Guiqi Polysaccharides/Chitosan/Alginate Composite Hydrogel Microspheres

A series of the Guiqi polysaccharides/chitosan/alginate composite hydrogel microspheres(GPcM)with different particle sizes were prepared with Guiqi polysaccharides(GP),chitosan(CS)and sodium alginate(Alg).The optimum preparation process was also determined by single factor and orthogonal experiment analysis.The GPcM were characterized by fourier transform infrared spectroscopy(FT-IR),scanning electron microscope(SEM),drug loading efficiency test(LE),encapsulation efficiency test(EE)and in vitro release study.The results showed that the Guiqi polysaccharides chitosan hydrogel(GPCH)and sodium alginate hydrogel(SAH)formed a crossover system in GPcM.The GPcM have a uniform particle size ranging from 395.1μm to 841.5μm.The drug loading efficiency and encapsulation efficiency of the GPcM were 56.3%and 72.6%,respectively.The bovine serum albumin(BSA)loaded in the GPcM released slowly within 180 h.The results suggested that the GPcM may have potential application value in drug sustained and controlled release system.

High performance strain sensor based on leather activated by micro-cracking conductive layer

Flexible strain sensors are capable to detect external force induced strain change owing to their unique ability to convert deformation into electrical signals.Generally,micro/nano patterning of conductive layer in strain sensor is an effective method to improve its sensitivity,however the sophisticated manipulation process is limited only in laboratory scale.In this report,a simple and scalable fabrication strategy was used to create micro-cracking conductive layer as an alternative patterning method to achieve high performance of strain sensor.In details,the sensor was fabricated using leather as the substrate to filtrated acidified multi-walled carbon nanotubes(a-MWCNTs)/layered double hydroxides(LDHs)suspension.During stretching process,micro-cracking structure emerged on the percolated a-MWCNTs/LDHs layer,causing a rise up of resistance according to increasing strain and generated a detectable electrical signal.The prepared sensor had a large detecting range(60%),high sensitivity(GF of 7238.92 at strain 30-60%),fast response(tensile response time of 270 ms),good stability and repeatability.The sensor also inherited the advantages of leather,such as biodegradability and good air permeability,and the introduction of a-MWCNTs/LDHs further enhanced its fire retardancy properties.These features ensured the sensor as an eco-friendly,comfortable and safe electronic device for human motion detection.

生物质基传感器的构筑及其在人体健康监测中的应用

随着柔性电子设备不断发展,可穿戴式柔性传感器在人体健康监测、电子皮肤、智能机器等领域表现出巨大的发展潜力。生物质材料作为一种源于生物体的可再生资源,具有价格低廉、绿色环保、亲肤透气、生物相容性好等优点,已被作为可穿戴柔性传感器的基底进行大量研究。生物质基传感器由于融合了生物质材料与传感元件的优良特性,因此可作为人体健康监测领域的理想选择。本文综述了常见柔性传感器(应变、压力、温度、生物)的结构、组成及工作原理,然后详细介绍了不同生物质基传感器的特点及其应用,所涉及的生物质材料主要包括胶原蛋白、明胶、纤维素、壳聚糖、海藻酸钠以及丝素蛋白等。之后,对生物质基传感器在人体健康监测(如物理信号、化学信号、生物电信号、热信号监测)中的应用进行了概述。最后,结合目前所面临的应用现状,指出了生物质基传感器在人体健康监测应用方面所面临的挑战及未来发展方向。

2020 Roadmap on two-dimensional nanomaterials for environmental catalysis

Environmental catalysis has drawn a great deal ofattention due to its clean ways to produce useful chemicals or carry out some chemical processes.Photocatalysis and electrocatalysis play important roles in these fields.They can decompose and remove organic pollutants from the aqueous environment,and prepare some fine chemicals.Moreover,they also can carry out some important reactions,such as 02 reduction reaction(ORR),O2 evolution reaction(OER),H2 evolution reaction(HER),CO2 reduction reaction(C02 RR),and N2 fixation(NRR).For catalytic reactions,it is the key to develop high-performance catalysts to meet the demand fortargeted reactions.In recentyears,two-dimensional(2 D) materials have attracted great interest in environmental catalysis due to their unique layered structures,which offer us to make use of their electronic and structural characteristics.Great progress has been made so far,including graphene,black phosphorus,oxides,layered double hydroxides(LDHs),chalcogenides,bismuth-based layered compounds,MXenes,metal organic frameworks(MOFs),covalent organic frameworks(COFs),and others.This content drives us to invite many famous groups in these fields to write the roadmap on two-dimensional nanomaterials for environmental catalysis.We hope that this roadmap can give the useful guidance to researchers in future researches,and provide the research directions.

Tropospheric NO_2 vertical column densities retrieved from ground-based MAX-DOAS measurements at Shangdianzi regional atmospheric background station in China

Ground-basedMulti-AXis Differential Optical Absorption Spectroscopy(MAX-DOAS)measurements were performed at Shangdianzi(SDZ)regional atmospheric background station in northern China from March 2009 to February 2011.The tropospheric NO_2vertical column densities(VCDs)were retrieved to investigate the background condition of the Beijing–Tianjin–Hebei developed economic circle in China.The seasonal variation of mean NO_2tropospheric VCDs(VCD_(Trop))at SDZ is apparent,with the maximum(1.3×10^(16)molec/cm^2)in February and the minimum(3.5×10^(15)molec/cm^2)in August,much lower than those observed at the Beijing city center.The average daytime diurnal variations of NO_2VCD_(Trop )are rather consistent for all four seasons,presenting the minimum at noon and the higher values in the morning and evening.The largest and lowest amplitudes of NO_2VCD_(Trop)diurnal variation appear in winter and in summer,respectively.The diurnal pattern at SDZ station is similar to those at other less polluted stations,but distinct from the ones at the urban or polluted stations.Tropospheric NO_2VCDs at SDZ are strongly dependent on the wind,with the higher values being associated with the pollution plumes from Beijing city.Tropospheric NO_2VCDs derived from ground-based MAX-DOAS at SDZ show to be well correlated with corresponding OMI(Ozone Monitoring Instrument)satellite products with a correlation coefficient R=0.88.However,the OMI observations are on average higher than MAX-DOAS NO_2VCDs by a factor of 28%,probably due to the OMI grid cell partly covering the south of SDZ which is influenced more by the pollution plumes from the urban areas.

All-inorganic TiO_(2)/Cs_(2)AgBiBr_(6) composite as highly efficient photocatalyst under visible light irradiation

In recent years, limited photocatalysis efficiency and wide band gap have hindered the application of TiO_(2) in the field of photocatalysis. A leading star in photocatalysis has been revealed as lead-free Cs_(2)AgBiBr_(6) double halide perovskite nanocrystals, owing to its strong visible light absorption and tunable band gap. In this work, this photocatalytic process was facilitated by a unique TiO_(2)/Cs_(2)AgBiBr_(6) composite, which was identified as an S-cheme heterojunction. TiO_(2)/Cs_(2)AgBiBr_(6) composite was investigated for its structure and photocatalytic behavior. The results showed that when the perovskite dosage is 40%, the photocatalytic rate of TiO_(2) could be boosted to 0.1369 min^(-1). This paper discusses and proposes the band gap matching, carrier separation, and photocatalytic mechanism of TiO_(2)/Cs_(2)AgBiBr_(6) composites, which will facilitate the generation of new ideas for improving TiO_(2)’s photocatalytic performance.

Hepatic venous pressure gradient measurement guiding nonselective beta-blocker therapy in a patient with clinically significant portal hypertension

Clinically significant portal hypertension(CSPH),defined as a hepatic venous pressure gradient(HVPG)≥10 mmHg,is an independent risk factor for decompensated events in patients with compensated cirrhosis.Currently,the Baveno VII consensus recommends using nonselective beta-blockers to treat compensated cirrhosis in patients with CSPH.Here,we report a unusual case of compensated cirrhosis with CSPH caused by hepatitis B,and we successfully adjust NSBBs drug treatment strategies monitoring by HVPG results and achieve response standards.Timely adjustment of NSBBs drug treatment strategies based on HVPG test results for patients with CSPH can improve the final response rate.

柔性导电高分子复合材料在应变传感器中的应用

柔性和可穿戴传感器最近十几年来的发展,使得它们在个性化医疗、人机交互和智能机器人等方面拥有良好的应用前景。由导电材料和弹性聚合物组成的柔性导电高分子复合材料具有高的可拉伸性、良好的柔韧性、优异的耐久性等优点,可用来制备传感范围宽、灵敏度高的柔性应变传感器。本文综述了基于柔性导电高分子复合材料的可拉伸应变传感器的分类(填充型、三明治型、吸附型应变传感器)和传感机理(隧穿效应,分离机制,裂纹扩展),并详细介绍了传感器所用复合材料的结构设计,包括内部结构(双逾渗网络、隔离、多孔、"砖混"结构)、表面结构(微裂纹、褶皱结构)和宏观结构(纤维状、网状、薄膜结构)。内部结构设计可降低材料的逾渗阈值,表面结构设计可提高传感器性能,每个宏观结构都有自己的特点。最后对应变传感器的材料选择、制备工艺、结构设计、附加性能、集成技术和应用方向等方面进行了展望。

Seasonal variation in surface ozone and its regional characteristics at global atmosphere watch stations in China

We investigated the seasonal and spatial ozone variations in China by using three-year surface ozone observation data from the six Chinese Global Atmosphere Watch(GAW)stations and tropospheric column ozone data from satellite retrieval over the period2010–2012. It is shown that the seasonal ozone variations at these GAW stations are rather different, particularly between the western and eastern locations. Compared with western China, eastern China has lower background ozone levels. However, the Asian summer monsoon(ASM) can transport photochemical pollutants from the southern to the northern areas in eastern China, leading to a northward gradual enhancement of background ozone levels at the eastern GAW stations. Over China, the tropospheric column ozone densities peak during spring and summer in the areas that are directly and/or indirectly affected by the ASM, and the peak time lags from the south to the north in eastern China. We also investigated the regional representativeness of seasonal variations of ozone at the six Chinese GAW stations using the yearly maximum tropospheric column month as indicator.The results show that the seasonal variation characteristics of ozone revealed by the Chinese GAW stations are typical, with each station having a considerable large surrounding area with the ozone maximum occurring at the same month. Ozone variations at the GAW stations are influenced by many complex factors and their regional representativeness needs to be investigated further in a broader sense.

聚合物基电磁屏蔽复合材料的结构设计与性能研究进展

对近年来关于聚合物基电磁屏蔽材料的报道进行了综述。重点总结分析了不同结构(如多孔结构、隔离结构和分层结构)及其他特殊结构聚合物基电磁屏蔽材料的屏蔽效能和屏蔽机制。与均匀分布聚合物基复合材料相比,通过结构设计使填料富集,再取向并连通从而形成高效导电网络,不仅能减少填料用量,且能有效提高复合材料的电磁屏蔽性能。最后,提出了聚合物基电磁屏蔽材料的未来发展方向。

聚(3,4-乙烯二氧噻吩)∶聚苯乙烯磺酸/无机纳米复合材料的制备及应用

聚(3,4-乙烯二氧噻吩)∶聚(苯乙烯磺酸)(PEDOT∶PSS)是一种水溶性导电高分子体系,具有易加工、高透光率及柔韧性等优点,但其应用范围仅限于作为电子器件的柔性电极材料。为了进一步扩大PEDOT∶PSS的应用范围,将无机纳米材料引入该体系实现材料的多功能化是较为有效的方法。本文首先介绍了PEDOT∶PSS/无机纳米复合材料最常用的四种制备方法,即原位法、共混法、自组装法、插层复合法,分别介绍了每种制备方法的原理和特点,并阐述了研究人员对复合材料的结构设计思路及引入的无机相对材料性能的影响。随后,综述了PEDOT∶PSS/无机纳米复合材料在传感器、太阳能电池、超级电容器、热电发电机等领域中应用的最新进展。最后指出了目前在PEDOT∶PSS/无机纳米复合材料的研究中面临的挑战,并对该材料的研究方向和发展趋势进行了展望。

Atmospheric extinction properties in Shenyang,China

Atmospheric visibility impairment due to human activities is becoming increasingly significant in metropolitan 8henyang, China. In this study, hourly data of relevant factors throughout the year 2010 in Shenyang were used to evaluate the local atmospheric extinction properties. The results show that the average coefficient of total extinction and aerosol single-scattering albedo in 2010 were 622.72 Mm^-1 and 0.87, respectively, values that are characteristic of the ＂municipal pollution type＂. Visibility is most impaired during winter and especially in January. The coefficient of total extinction exhibits a single daily cycle with a maximum at 5-6 am and a minimum at 3 pm. The mean extinction contributions of the constituents, from high to low, were particle scattering （87.49%）, particle absorption, gas absorption, and gas scattering. The extinction contribution of gas molecules was little more than 4.5%, far smaller than that of particles. Scattering by particles was the main contributor to extinction, especially in the morning and around midnight.

Insights into functional polymer-based organic-inorganic nanocomposites as leather finishes

Nowadays,the increasing demands from consumer challenges the traditional leather products.Traditional polymer leather finishes gradually lose their dominant position in the market.To address this issue,recent research effort has been devoted to developing polymer-based organic-inorganic nanocomposite leather finishes due to their various functional properties including antibacterial,self-cleaning and water-resistant property.In this review,we provide a comprehensive overview of synthesis of polymer-based organic-inorganic nanocomposites and their application as functional leather finishes.With the perspective of their properties and current challenges,an outlook in the future development about crafting functional and high-quality leather finishes are further proposed.

Direct Retrieval of NO_(2)Vertical Columns from UV-Vis(390-495nm)Spectral Radiances Using a Neural Network

Satellite retrievals of columnar nitrogen dioxide(NO_(2))are essential for the characterization of nitrogen oxides(NO_(x))processes and impacts.The requirements of modeled a priori profiles present an outstanding bottleneck in operational satellite NO_(2)retrievals.In this work,we instead use neural network(NN)models trained from over 360,000 radiative transfer(RT)simulations to translate satellite radiances across 390-495nm to total NO_(2)vertical column(NO_(2)C).Despite the wide variability of the many input parameters in the RT simulations,only a small number of key variables were found essential to the accurate prediction of NO_(2)C,including observing angles,surface reflectivity and altitude,and several key principal component scores of the radiances.In addition to the NO_(2)C,the NN training and cross-validation experiments show that the wider retrieval window allows some information about the vertical distribution to be retrieved(e.g.,extending the rightmost wavelength from 465 to 495 nm decreases the root-mean-square-error by 0.75%)under high-NO_(2)C conditions.Applying to four months of TROPOMI data,the trained NN model shows strong ability to reproduce the NO_(2)C observed by the ground-based Pandonia Global Network.The coefficient of determination(R2,0.75)and normalized mean bias(NMB,-33%)are competitive with the level 2 operational TROPOMI product(R^(2)=0:77,NMB=−29%)over clear(geometric cloud fraction<0:2)and polluted(NO_(2)C≥7:5×10^(15)molecules/cm2)regions.The NN retrieval approach is~12 times faster than predictions using high spatial resolution(~3 km)a priori profiles from chemical transport modeling,which is especially attractive to the handling of large volume satellite data.