Stitching Perovskite Grains with Perhydropoly(Silazane)Anti-Template-Agent for High-Efficiency and Stable Solar Cells Fabricated in Ambient Air

All inorganic CsPbI_(3)perovskite solar cells(PSCs)have emerged as disruptive photovoltaic technology owing to their admirable photoelectric properties and the non-volatile active layer.However,the phase instability against moisture severely limits the fabrication environment for the high-efficiency devices,breaking through the confinement region to achieve scalable manufacturing has been the primary issue for future commercialization.Here,we develop a curing-anti-solvent strategy for fabricating high-quality and stable black-phase CsPbI_(3)perovskite films in ambient air by introducing an inorganic polymer perhydropolysilazane(PHPS)into methyl acetate to form anti-template agent.The cross-linked PHPS reduces moisture erosions while the hydrolyzate silanol network(–Si(OH)_(4)^(–))controls the perovskite crystal growth by forming Lewis adducts with PbI_(2)during the fabrication.The polycondensation adduct of Si–O–Si/Si–O–Pb strongly binds to CsPbI_(3)grains as a shield layer to hamper phase transition.Using the inorganic CsPbI_(3)perovskite thin-film with PHPS-modified anti-solvent processing as the light absorber,the n–i–p planar solar cell achieved an efficiency of 19.17%under standard illumination test conditions.More importantly,the devices showed excellent moisture stability,retaining about 90%of the initial efficiency after 1000 h under 30%RH.

Co-planted barnyardgrass reduces rice yield by inhibiting plant above-and belowground-growth during post-heading stages

Barnyardgrass (Echinochloa spp.) is the most common noxious weed in rice paddies as it inhibits rice growth and reduces grain yield.To date,little information is available on above-and belowgroundgrowth changes in rice due to neighboring barnyardgrass.This study aimed to investigate the changes in root traits and shoot growth of rice when it is grown with different kinds of barnyardgrass.Japonica rice plants (var.Nanjing 9108) were co-cultured with two varieties of Echinochloa crusgalli (L.) Beauv.(EP,var.mitis (pursh) Petern;EH,var.zelayensis (H.B.K.) Hitchc),and E.colonum (L.) Link (EL) in the field in 2017 and 2018.Four treatments included control (i.e.,weed free rice plants) and co-cultures with each of three barnyardgrasses (EP,EH,and EL).The results revealed that EP,EH,and EL treatments significantly reduced rice grain yields by 30.6%–36.2%,42.5%–46.5%,and 10.6%–14.3%,respectively.Shoot growth including shoot dry weight,leaf photosynthetic rate,zeatin (Z) and zeatin riboside (ZR) in grains,and activities of key enzymes involved in sucrose-to-starch conversion in grains and root traits,such as length density,root dry weight,total absorbing surface area,active absorption surface area,oxidation activity,and Z+ZR contents in roots were dramatically reduced during post-heading stages of rice when grown with the three kinds of barnyardgrass.Moreover,above-mentioned rice shoot growth indices were strongly and positively correlated with root traits.These results suggested the decrease in rice shoot growth and root traits during post-heading stages contributes to the reduction in the rice yield when it grows with barnyardgrass neighbors.

Multifunctional cellular carbon foams derived from chitosan toward self-cleaning, thermal insulation, and highly efficient microwave absorption properties

To adapt the practical demand,designing and constructing the multifunctional microwave absorbers(MAs)is the key future direction of research and development.However,effective integrating the multiple functions into a single material remains a huge challenge.Herein,cellular carbon foams(CCFs)with different porous structures were elaborately designed and fabricated in high efficiency through a facile continuous freeze-drying and carbonization processes using a sustainable biomass chitosan as the precursor.The obtained results revealed that the thermal treated temperature and g-C_(3)N_(4) amount played a great impact on the carbonization degrees,pore sizes,and morphologies of CCFs,which led to their tunable electromagnetic(EM)parameters,improved conduction loss,and polarization loss abilities.Owing to the special cellular structure,the designed CCFs samples simultaneously displayed the strong absorption capabilities,broad absorption bandwidths,and thin matching thicknesses.Meanwhile,the as-prepared CCFs exhibited the strong hydrophobicity and good thermal insulation,endowing its attractive functions of self-cleaning and thermal insulation.Therefore,our findings not only presented a facile approach to produce different porous structures of CCFs,but also provided an effective strategy to develop multifunctional high-performance MAs on basis of three-dimensional CCFs.

Universal paradigm of ternary metacomposites with tunable epsilon-negative and epsilon-near-zero response for perfect electromagnetic shielding

CaCu_(3)Ti_(4)O_(12)(CCTO)ceramic nanocomposites incorporating graphene–carbon black(GRCB)fillers were fabricated by spark plasma sintering process.The percolative effects of conductive GRCB fillers on dielectric response of GRCB/CCTO ternary metacomposites were systematically investigated.The weakly real permittivity(ε′)-negative response(ε′~−1×10^(2))was achieved which originated from weakly low-frequency plasmonic state of free carriers within constructed GRCB networks.With enhancing three-dimensional GRCB network,the plasma frequency of metacomposites increased while the damping factor decreased.Herein,theε′-negative values of metacomposites were tuned from−10^(2) to−10^(4) orders of magnitude andε′-near-zero(ENZ)frequencies from~142 to~340 MHz which substantially benefited from the moderate carrier concentration of GRCB dual fillers.The Drude model and equivalent circuit models were adopted to demonstrate dielectric and electrical characteristics.The obtained metacomposites show strong EM shielding effect along with enhanced plasmonic oscillation and even better achieving perfect EM shielding effect in ENZ media.This work achieves the tunableε′-negative andε′-near-zero response and more importantly clarifies its regulation mechanism in ceramic-based ternary metacomposites,which opens up the possibility of designing high-performance EM shielding materials based on metacomposites.

Hierarchical engineering of CoNi@Air@C/SiO_(2)@Polypyrrole multicomponent nanocubes to improve the dielectric loss capability and magnetic-dielectric synergy

Impedance matching characteristics and loss capabilities including magnetic loss,polarization loss and conduction loss are critical factors to improve microwave absorption performances(MAPs).To elevate these aspects,herein,yolk-shell structured CoNi@Air@C/SiO_(2)@Polypyrrole(PPy)magnetic multicomponent nanocubes(MCNCs)were designed and successfully fabricated in high efficiency through a continuous co-precipitation route,classical Stöber method,thermal treatment and polymerization reaction.The obtained results indicated that the formation of SiO_(2) effectively stabilized the cubic geometrical morphology and yolk-shell structure during the high-temperature pyrolysis process.The introduction of PPy greatly boosted their polarization loss and conductive loss capabilities.Therefore,the as-prepared yolkshell structured CoNi@Air@C/SiO_(2)@PPy MCNCs presented superior MAPs compared to CoNi@Air@C/SiO_(2) MCNCs.Furthermore,by regulating the content of PPy,the obtained CoNi@Air@C/SiO_(2)@PPy MCNCs displayed tunable and excellent comprehensive MAPs in terms of strong absorption capabilities,broad frequency bandwidths and thin matching thicknesses,which could be ascribed to the unique structure and excellent magnetic-dielectric synergistic effect.Therefore,our findings provided an alternative pathway to effectively utilize the magnetic-dielectric synergy and loss capabilities for the developing yolk-shell structured magnetic MCNCs as the strong wideband microwave absorbers.

Tunable and improved microwave absorption of flower-like core@shell MFe_(2)O_(4)@MoS_(2)(M=Mn,Ni and Zn)nanocomposites by defect and interface engineering

Previous results revealed that the defect and/or interface had a great impact on the electromagnetic pa-rameters of materials.In order to understand the main physical mechanisms and effectively utilize these strategies,in this study,M Fe_(2)O_(4)and flower-like core@shell M Fe_(2)O_(4)@MoS_(2)(M=Mn,Ni,and Zn)sam-ples with different categories were elaborately designed and selectively produced in large scale through a simple two-step hydrothermal reaction.We conducted the systematical investigation on their microstruc-tures,electromagnetic parameters and microwave absorption performances(MAPs).The obtained results revealed that the large radius of M^(2+)cation could effectively boost the concentration of oxygen vacancy in the M Fe_(2)O_(4)and M Fe_(2)O_(4)@MoS_(2)samples,which resulted in the improvement of dielectric loss capabil-ities and MAPs.Furthermore,the introduction of MoS_(2)nanosheets greatly improved the interfacial effect and enhanced the polarization loss capabilities,which also boosted the MAPs.By taking full advantage of the defect and interface,the designed M Fe_(2)O_(4)@MoS_(2)samples displayed tunable and excellent com-prehensive MAPs including strong absorption capability,wide absorption bandwidth and thin matching thicknesses.Therefore,the clear understanding of defect and interface engineering made these strategies well elaborately designed and applicable to improving MAPs.

Anion regulating endows core@shell structured hollow carbon spheres@MoSxSe_(2−x)with tunable and boosted microwave absorption performance

Due to the good manipulation of electronic structure and defect,anion regulating should be a promising strategy to regulate the electromagnetic(EM)parameters and optimize the EM wave absorption performances(EMWAPs).In this work,we proposed a facile route for the large-scale production of core@shell structured hollow carbon spheres@MoSxSe_(2−x)(x=0.2,0.6,and 1.0)multicomponent nanocomposites(MCNCs)through a mild template method followed by hydrothermal process.The obtained results revealed that the designed hollow carbon spheres@MoSxSe_(2−x)MCNCs presented the improved sulfur vacancy concentration by regulating the x value from 0.2 to 1.0.The obtained hollow carbon spheres@MoSxSe_(2−x)MCNCs displayed the extraordinary comprehensive EMWAPs because of the introduced abundant defects and excellent interfacial effects.Furthermore,the as-prepared hollow carbon spheres@MoSxSe_(2−x)MCNCs presented the progressively improved comprehensive EMWAPs with the x value increasing from 0.2 to 1.0,which could be explained by their boosted polarization loss abilities and impedance matching characteristics originating from the enhanced sulfur vacancy concentration.Therefore,our findings not only demonstrated that the anion regulating was a promising method to optimize EM parameters and EMWAPs,but also provided a facile route to design the transition metal dichalcogenides-based MCNCs as the much more attractive candidates for highperformance microwave absorbers.

Carbon nanotube-carbon black/CaCu_(3)Ti_(4)O_(12) ternary metacomposites with tunable negative permittivity and thermal conductivity fabricated by spark plasma sintering

Metacomposites with negative permittivity usually possess huge dielectric loss,showing potential for micro-wave attenuation devices where huge heat would generate.Herein,carbon nanotube-carbon black/CaCu_(3-)Ti_(4)O_(12)(CNT-CB/CCTO)ternary metacomposites were fabricated by spark plasma sintering.The CNT-CB dualphase filler was pre-pared through electrostatic selfassembly process in order to construct an effective 3-dimensional(3D)carbon network in CCTO matrix.The percolation threshold of CNT-CB/CCTO composites was identified at filler content of 12.52 wt%which accompanied with an essential change of conduction mechanism.The negative permittivity was derived from low-frequency plasmonic state of the 3D carbon network,described by Drude model.The problem of heat transport,generally occurring in negative permittivity materials,has been solved and optimized in obtained ternary metacomposites beneftting from the substantially high thermal conductivity(9.49-2.00 W·m^(-1)·K^(-1))and diffusivity(2.74-1.22mm^(2)·s^(-1)).This work could spark significant development of practical application of metacomposites on novel electronic devices and electromagnetic apparatus.

碳载体空位工程助力原位合成的Pt纳米枝晶促进电催化氧气还原

质子交换膜燃料电池(PEMFCs)因其高能量密度、低操作温度和环保等特性,被视为极具潜力的能量转换系统.目前,碳载铂颗粒(Pt/C)是PEMFCs阴极氧还原反应(ORR)中使用最广泛的催化剂.然而,Pt与碳载体间的电子结构差异导致Pt纳米颗粒(Pt NPs)易从碳载体上脱落,严重降低了ORR的催化活性.此外,Pt的高成本和稀缺性也限制了其广泛应用.相比之下,Pt纳米枝晶(NDs)因具有高利用率的表面活性位点而备受关注.然而,Pt NDs的合成通常需要严格控制反应条件,且其与碳基底间的弱相互作用易导致活性位点损失和性能下降.因此,开发具有强金属载体相互作用的Pt复合碳催化剂对PEMFCs的实际应用至关重要.本文通过原位Cl-介导的生长策略,结合碳本征空位工程,成功制备了分散在富含碳本征空位的中空氮掺杂碳基底上的Pt NDs催化剂(Pt@HNC-V-800).拉曼光谱和电子顺磁共振光谱结果表明,碳本征空位的形成机制源于碳基底结构中氮原子的耗散,该过程引起碳原子的重新排列,进而产生了丰富的本征缺陷位点.X射线吸收光谱和X射线光电子能谱结果表明,与无碳空位的Pt@HNC催化剂相比,富含本征碳空位的样品(Pt@HNC-V-800)表现出较低的Pt-Pt键配位数(8.64)和更强的给电子效应.得益于Pt NDs丰富的活性位点及其与本征碳空位基底之间的强电子效应,Pt@HNC-V-800的ORR半波电位高达0.947 V,质量活性和比表面活性分别为1.55 A mg^(-1) Pt和1.85 mA cm^(-2),是商用Pt/C的8.2和6.8倍(0.191 A mg^(-1)Pt和0.27 mA cm^(-2)).加速耐久性测试结果表明,经20000次电势循环后,Pt@HNC-V-800的活性无明显变化,其活性损失远低于无碳本征空位的Pt@HNC材料和商业Pt/C催化剂.因此,与无碳本征空位的Pt@HNC材料相比,Pt@HNC-V-800的ORR活性和稳定性都有较大提升,进一步证实了碳本征空位工程协同Pt NDs策略的优越性.此外,密度泛函理论计算结果表明,Pt@HNC-V的丰富空位降低了氧中间体过电势,优化了ORR中间体在Pt NDs上的吸附能,进而提高了催化剂的ORR本征活性.同时,富碳本征空位的存在增强了Pt NDs在碳载体上的结合能,使Pt NDs不易在电势循环过程中脱离碳载体,从而增强了稳定性.综上所述,本文通过Pt NDs与碳本征空位工程协同效应策略,精准调控碳负载Pt基催化剂的结构,大幅提升其在酸性条件下的ORR性能,为进一步设计高性能的ORR电催化剂提供了新思路.

基于VS的SF_6气体泄漏报警系统设计

针对电力系统中的灭弧介质和绝缘气体SF_6气体在断路器的分断操作过程中产生的分解物对人体有害这一现象,文章研究了SF_6气体泄漏报警系统的设计。系统以上位机监控软件为主操作系统,基于Microsoft Visual Studio进行上位机监控软件开发。以SF_6+O_2+温湿度传感器模块为数据采集单元,配合风机、声光报警器,继电器控制板模块共同构成在线监测气体泄漏报警系统。测试结果表明,系统能实现SF_6气体在线监测、自动报警和自动排风功能。

The Genome of Medicinal Plant Macleaya cordata Provides New Insights into Benzylisoquinoline Alkaloids Metabolism

在动物农业和药的抗菌素的 overuse 引起了一系列潜在的威胁到公共健康。Macleaya cordata 是从 Papaveraceae 家庭的药用的植物种，提供为抗菌剂的制造的一个安全资源为家畜喂添加剂。从 M. 的活跃成分 ? cordata 被知道包括 benzylisoquinoline 碱(偏爱) 象 sanguinarine (圣) 和 chelerythrine (CHE ) 那样的 ?，而是他们的新陈代谢的小径还得在这非模型植物被学习。在 M. 的圣和 CHE 的活跃生合成 ? cordata 被喂 13标记 C 的酷氨酸。为了增加，推进卓见，我们 de novo 定序 M 的整个染色体。cordata，第一从 Papaveraceae 家庭被定序。M.? 盖住 378 Mb 的 cordata 染色体与 43.5%being 编码 22,328 预言的编码蛋白质的基因 transposable 元素。作为基础 eudicot 的一个成员， M.? cordata 染色体缺乏 ? 发生在几乎所有 eudicots 的 paleohexaploidy 事件。从 genomics 数据， 16 的一个完全的集合 ? 新陈代谢 ? 为圣和 CHE 生合成的基因被检索，并且 14 项他们的生物化学的活动被验证。这些 genomics 和新陈代谢的数据在 M. 显示出保存 BIA 新陈代谢的小径 ? cordata 并且由庄稼改进或微生物引起的小径重建为圣和 CHE 的未来生产提供知识基础。

Magnetic-dielectric synergy and interfacial engineering to design yolk-shell structured CoNi@void@C and CoNi@void@C@MoS_(2) nanocomposites with tunable and strong wideband microwave absorption

In order to effectively utilize the magnetic-dielectric synergy and interfacial engineering,in this paper,yolk–shell structured magnetic multicomponent nanocomposites(MCNCs)including CoNi@void@C and CoNi@void@C@MoS_(2) were produced in large scale by in-situ pyrolysis of cubic CoNi Prussian blue analogs(PBAs)followed by the hydrothermal process,respectively.Because of their unique structures,excellent synergistic effect between dielectric and magnetic loss,the as-prepared CoNi@void@C and CoNi@void@C@MoS_(2) MCNCs displayed very outstanding electromagnetic wave absorption performances(EMWAPs)including strong absorption capabilities,broad absorption bandwidth and thin matching thicknesses.Furthermore,the as-prepared CoNi@void@C and CoNi@void@C@MoS_(2) MCNCs well maintained the cubic configuration of CoNi PBAs even after the thermal treatment and hydrothermal processes.The unique structure and formed carbon layers effectively prevented the corrosion of internal CoNi alloy during the formation of MoS_(2),and CoNi@void@C@MoS_(2) MCNCs with different MoS_(2) contents could be synthesized by controlling the hydrothermal temperature.The obtained results revealed that the EM parameters,dielectric and magnetic loss capabilities of CoNi@void@C@MoS_(2) MCNCs could be tuned by controlling hydrothermal temperature and filler loading,which made their outstanding EMWAPs could be achieved in different frequency regions.Taking account of simple process,low density and high chemical stability,our findings provided a new and effective pathway to develop the strong wideband microwave absorbers.

Defect and interface engineering in core@shell structure hollow carbon@MoS_(2)nanocomposites for boosted microwave absorption performance

Defect and interface engineering are efficient approaches to adjust the physical and chemical properties of nanomaterials.In order to effectively utilize these strategies for the improvement of microwave absorption properties(MAPs),in this study,we reported the synthesis of hollow carbon shells and hollow carbon@MoS_(2)nanocomposites by the template-etching and templateetching-hydrothermal methods,respectively.The obtained results indicated that the degree of defect for hollow carbon shells and hollow carbon@MoS_(2)could be modulated by the thickness of hollow carbon shell,which effectively fulfilled the optimization of electromagnetic parameters and improvement of MAPs.Furthermore,the microstructure investigations revealed that the precursor of hollow carbon shells was encapsulated by the sheet-like MoS_(2)in high efficiency.And the introduction of MoS_(2)nanosheets acting as the shell effectively improved the interfacial effects and boosted the polarization loss capabilities,which resulted in the improvement of comprehensive MAPs.The elaborately designed hollow carbon@MoS_(2)samples displayed very outstanding MAPs including strong absorption capabilities,broad absorption bandwidth,and thin matching thicknesses.Therefore,this work provided a viable strategy to improve the MAPs of microwave absorbers by taking full advantage of their defect and interface engineering.

Microstructure optimization of core@shell structured MSe_(2)/FeSe_(2)@MoSe_(2)(M=Co,Ni)flower-like multicomponent nanocomposites towards high-efficiency microwave absorption

In this work,we put forward a scheme to exquisitely design and selectively synthesize the core@shell structured MSe_(2)/FeSe_(2)@MoSe_(2)(M=Co,Ni)flower-like multicomponent nanocomposites(MCNCs)through a simple two-step hydrothermal reaction on the surfaces of MFe_(2)O_4 nanospheres with the certain amounts of Mo and Se sources.With increasing the amounts of Mo and Se sources,the obtained core@shell structured MSe_(2)/FeSe_(2)@MoSe_(2)(M=Co,Ni)MCNCs with the enhanced content of MoSe_(2)and improved flower-like geometry morphology could be produced on a large scale.The obtained results revealed that the as-prepared samples displayed improved comprehensive microwave absorption properties(CMAPs)with the increased amounts of Mo and Se sources.The as-prepared CoSe_(2)/FeSe_(2)@MoSe_(2)and NiSe_(2)/FeSe_(2)@MoSe_(2)MCNCs with the well-defined flower-like morphology could simultaneously present the outstanding CMAPs in terms of strong absorption capability,wide absorption bandwidth,and thin matching thicknesses,which mainly originated from the conduction loss and flower-like geometry morphology.Therefore,the findings not only develop the very desirable candidates for high-performance microwave absorption materials but also pave a new way for optimizing the CMAPs through tailoring morphology engineering.

Unexpected elastic isotropy in a black phosphorene/TiC2 van der Waals heterostructure with flexible Li-ion battery anode applications

Recently, flexible electrodes with biaxial/omnidirectional stretchability haveattracted significant attention. However, most existing pliable electrode materialscan be only stretched in one direction. In this work, an unexpected isotropic vander Waals （vdW） heterostructure is proposed, based on the assembly of two-dimensional crystals of anisotropic black phosphorene （BP） and transition metalcarbide （TIC2）. Using vdW-corrected density functional theory calculations, theBPFFiC2 vdW heterostructure was predicted to have excellent structural andmechanical stability, superior electrical conductivity, omnidirectional flexibility,and a high Li storage capacity. We have unraveled the physical origin of theexcellent stability, as well as the Li adsorption preferences of the lithiatedheterostructure, based on a three-step analysis of the stability of the Li-adsorptionprocesses. In addition, the BP/TiC2 vdW heterostructure can also be applied asthe anode material for flexible Na-ion batteries because of its high Na storagecapacity and strong Na binding. However, compared with Na adsorption, thecapacity is higher, and the adsorption energy is more negative for Li adsorption.Our findings provide valuable insights into the exploration of a rich variety ofvdW heterostructures for next-generation flexible energy storage devices.

The Genomes of the Allohexaploid Echinochloa crus-galli and Its Progenitors Provide Insights into Polyploidization-Driven Adaptation

The hexaploid species Echinochloa crus-galli is one of the most detrimental weeds in crop fields,especially in rice paddies.Its evolutionary history is similar to that of bread wheat,arising through polyploidization after hybridization between a tetraploid and a diploid species.In this study,we generated and analyzed high-quality genome sequences of diploid(E.haploclada),tetraploid(E.oryzicola),and hexaploid(E.crus-galli)Echinochloa species.Gene family analysis showed a significant loss of disease-resistance genes such as those encoding NB-ARC domain-containing proteins during Echinochloa polyploidization,contrary to their significant expansionduring wheat polyploidization,suggesting that natural selection might favor reduced investment in resistance in this weed to maximize its growth and reproduction.In contrast to the asymmetric patterns of genome evolution observed in wheat and other crops,no significant differences in selection pressure were detected between the subgenomes in E.oryzicola and E.crus-galli.In addition,distinctive differences in subgenome transcriptome dynamics during hexaploidization were observed between E.crus-galli and bread wheat.Collectively,our study documents genomic mechanisms underlying the adaptation of a major agricultural weed during polyploidization.The genomic and transcriptomic resources of three Echinochloa species and new insights into the polyploidization-driven adaptive evolution would be useful for future breeding cereal crops.

Modelling impacts of high-speed rail on urban interaction with social media in China’s mainland

High-Speed Rail(HSR)has increasingly become an important mode of inter-city transportation between large cities.Inter-city interaction facilitated by HSR tends to play a more prominent role in promoting urban and regional economic integration and development.Quantifying the impact of HSR’s interaction on cities and people is therefore crucial for long-term urban and regional development planning and policy making.We develop an evaluation framework using toponym information from social media as a proxy to estimate the dynamics of such impact.This paper adopts two types of spatial information:toponyms from social media posts,and the geographical location information embedded in social media posts.The framework highlights the asymmetric nature of social interaction among cities,and proposes a series of metrics to quantify such impact from multiple perspectives-including interaction strength,spatial decay,and channel effect.The results show that HSRs not only greatly expand the uneven distribution of inter-city connections,but also significantly reshape the interactions that occur along HSR routes through the channel effect.