One-Step Scalable Fabrication of Nitrogen and Chlorine Co-doped Graphene by Electrochemical Exfoliation for High-Performance Supercapacitors

The stacking and aggregation of graphene nanosheets have been obstacles to their application as electrode materials for microelectronic devices.This study deploys a one-step,scalable,facile electrochemical exfoliation technique to fabricate nitrogen(N)and chlorine(Cl)co-doped graphene nanosheets(i.e.,N-Cl-G)via the application of constant voltage on graphite in a mixture of 0.1 mol/L H_(2)SO_(4)and 0.1 mol/L NH_(4)Cl without using dangerous and exhaustive operation.The introduction of Cl(with its large radius)and N,both with high electrical negativity,facilitates the modulation of the electronic structure of graphene and creation of rich structural defects in it.Consequently,in the as-constructed supercapacitors,N-Cl-G exhibits a high specific capacitance of 77 F/g at 0.2 A/g and remarkable cycling stability with 91.7%retention of initial capacitance after 20,000 cycles at 10 A/g.Furthermore,a symmetrical supercapacitor assembled with N-Cl-G as the positive and negative electrodes(denoted as N-Cl-G//N-Cl-G)exhibits an energy density of 3.38 Wh/kg at a power density of 600 W/kg and superior cycling stability with almost no capacitance loss after 5000 cycles at 5 A/g.This study provides a scalable protocol for the facile fabrication of high-performance co-doped graphene as an electrode material candidate for supercapacitors.

Exploration and Research on the Development of Higher Vocational English Education in Guangxi

With the acceleration of economic development and globalization and the rapid development of China’s foreign economy,the position of English education in higher vocational education has become increasingly prominent.Particularly in the multi-ethnic and multi-cultural areas of Guangxi Zhuang Autonomous Region,higher vocational education undertakes the responsibility of talent export for the construction of the China-ASEAN foreign trade exchange platform.However,the current phenomena and problems existing in higher vocational English education in Guangxi need to be deeply discussed and solved.Therefore,this paper discusses the development ideas of English education mode in Guangxi higher vocational education and studies the feasibility suggestions,in order to provide a reference for the future development of higher vocational English education in Guangxi.

Structure elucidation,immunomodulatory activity,antitumor activity and its molecular mechanism of a novel polysaccharide from Boletus reticulatus Schaeff

A new water-soluble heteropolysaccharide with a molecular weight of 15 k Da was isolated from the fruiting bodies of Boletus reticulatus Schaeff.Structural characterization results revealed that B.reticulatus Schaeff polysaccharide(BRS-X)had a backbone of 1,6-linkedα-D-galactose and 1,2,6-linkedα-D-galactose which branches were mainly composed of a terminal 4-linkedβ-D-glucose and the ratio of D-galactose and D-glucose was 5:1.Bioactivity assays indicated that BRS-X displayed a strong proliferative activity in T cells and B cells and promoted the secretion of immunoglobulin G(Ig G),Ig E,Ig D and Ig M.In addition,BRS-X could facilitate the proliferation and phagocytosis of RAW264.7 cells and could significantly inhibit the growth of tumors in S180-bearing mice.The results of transcriptome sequencing analysis illustrated that total 46 genes enriched in MAPK and total 34 genes enriched in PI3 K/Akt signaling pathways in BRS-X group.The protein VEGF and VEGFR expression were significantly reduced under the treatment with BRS-X.These findings provide a scientific basis for the edible and medicinal value of BRS-X.

Late spring cold reduces grain number at various spike positions by regulating spike growth and assimilate distribution in winter wheat

Late spring cold(LSC) occurred in the reproductive period of wheat impairs spike and floret differentiation during the reproductive period,when young spikelets are very cold-sensitive.However,under LSC,the responses of wheat spikelets at various positions,leaves,and stems and the interactions between them at physiological levels remain unclear.In the present study,two-year treatments at terminal spikelet stage under two temperatures(2 C,-2 C) and durations(1,2,and 3 days) were imposed in an artificial climate chamber to compare the effects of LSC on grain number and yield in the wheat cultivars Yannong 19(YN19,cold-tolerant) and Xinmai 26(XM26,cold-sensitive).The night temperature regimes were designed to reproduce natural temperature variation.LSC delayed plant growth and inhibited spike and floret differentiation,leading to high yield losses in both cultivars.LSC reduced dry matter accumulation(DMA,g) in spikes,stems,and leaves,reducing the DMA ratios of the spike to leaf and spike to stem.Plant cell wall invertase(CWINV) activity increased in upper and basal spikelets in YN19,whereas CWINV increased in middle spikelets in XM26.Under LSC,soluble sugar and glucose were transported and distributed mainly in upper and basal spikelets for glume and rachis development,so that spike development was relatively complete in YN19,whereas the upper and basal spikelets were severely damaged and most of the glumes in middle spikelets were relatively completely developed in XM26,resulting in pollen abortion mainly in upper and basal spikelets.The development of glumes and rachides was influenced and grain number per spike was decreased after LSC,with kernels present mainly in middle spikelets.Overall,reduced total DMA and dry matter partitioning to spikes under LSC results in poor spikelet development,leading to high losses of grain yield.

Electrochromic-Induced Rechargeable Aqueous Batteries: An Integrated Multifunctional System for Cross-Domain Applications

Multifunctional electrochromic-induced rechargeable aqueous batteries(MERABs) integrate electrochromism and aqueous ion batteries into one platform, which is able to deliver the conversion and storage of photo-thermal-electrochemical sources.Aqueous ion batteries compensate for the drawbacks of slow kinetic reactions and unsatisfied storage capacities of electrochromic devices. On the other hand, electrochromic technology can enable dynamically regulation of solar light and heat radiation. However,MERABs still face several technical issues, including a trade-off between electrochromic and electrochemical performance, low conversion efficiency and poor service life. In this connection, novel device configuration and electrode materials, and an optimized compatibility need to be considered for multidisciplinary applications. In this review,the unique advantages, key challenges and advanced applications are elucidated in a timely and comprehensive manner. Firstly, the prerequisites for effective integration of the working mechanism and device configuration, as well as the choice of electrode materials are examined. Secondly, the latest advances in the applications of MERABs are discussed, including wearable, self-powered, integrated systems and multisystem conversion. Finally, perspectives on the current challenges and future development are outlined, highlighting the giant leap required from laboratory prototypes to large-scale production and eventual commercialization.

Tunable Bistability in the Goos–H?nchen Effect with Nonlinear Graphene

We present a planar model system of a silica covered with a monolayer of nonlinear graphene to achieve a tunable Goos–H?nchen(GH) shift in the terahertz range. It is theoretically found that the transition between a negative shift and a large positive one can be realized by altering the intensity of incident light. Moreover, by controlling the chemical potential of graphene and the incident angle of light, we can further control the tunable GH shift dynamically. Numerical simulations for GH shifts based on Gaussian waves are in good agreement with our theoretical calculations.

Enhancing the formability of FeSi6.5 steel by the anodic polarization

The effect of anodic polarization on the plastic deformation behavior and formability of FeSi6.5 steel at room temperature was experimentally investigated through uniaxial tensile and drawing of wire specimen in sulfuric acid solution with current densities of 0-40 mA/cm2.The formability of the FeSi6.5 steel was significantly improved after the anodic polarization.The plastic elongation of the specimen as an anode in the electrochemical environment was 4.4%-7%,but 2.7%in the air.The drawing force under the anodic polarization decreased by 12.5%-26%compared to that in deionized water.The softening is mainly attributed to the relief in work hardening caused by surface atomic dissolution.The work hardening mechanism of the FeSi6.5 steel wires under anodic polarization condition was analyzed using Hollomon equation and Voce relation combined with the Kocks-Mecking approach.These data support the view that the surface atom dissolution facilitates dislocation slip.FeSi6.5 steel wires were obtained using electrochemical cold drawing and presented a smooth surface and good ductility without crack after five-pass drawing with a total cross-section area reduction of 88%.The drawing with the assistance of anodic polarization is a promising technology for processing hard and brittle metal materials.

Study of Organochlorine Pesticides in Eco-geochemical Survey of Soil in Shandong Province

Based on a comprehensive eco-geochemical survey of Shandong Province, the differences in pesticide residue situation and contents of DDTs and HCHs in the soils of Yantai City and Southwest Shandong Province(abbreviated as SSP) were studied in this paper. The results showed that the detection rates of DDTs and HCHs in the soil of SSP were apparently higher than Yantai City. However, the mean contents of DDTs and HCHs in the soil of Yantai were 9 and 25 times of SSP, respectively, and higher than the mean contents of many other cities and areas. p,p′-DDE was the main pesticide residual form in the soil of SSP. It is recognized as the degradation product of DDTs in oxidation environment in past, nevertheless, 5.52% of the soils in Yantai City still have a little of DDT input recently, which has posed a big impact on soil environment quality. β-HCH was the main form of the four isomers of HCHs in Yantai City, and α-HCH/γ-HCH in SSP was low. These reveal that the residual time of HCHs in the soils of both the two areas has a long period. After primary analysis, the risk of DDTs and HCHs in the soil of SSP is low, but DDTs in the soil of Yantai City still has a certain risk.

Better engineering layered vanadium oxides for aqueous zinc‐ion batteries: Going beyond widening the interlayer spacing

Aqueous zinc‐ion batteries(ZIBs)are regarded as among the most promising candidates for large‐scale grid energy storage,owing to their high safety,low costs,and environmental friendliness.Over the past decade,vanadium oxides,which are exemplified by V2O5,have been widely developed as a class of cathode materials for ZIBs,where the relatively high theoretical capacity and structural stability are among the main considerations.However,there are considerable challenges in the construction of vanadium‐based ZIBs with high capacity,long lifespan,and excellent rate performance.Simple widenings of the interlayer spacing in the layered vanadium oxides by pre‐intercalations appear to have reached their limitations in improving the energy density and other key performance parameters of ZIBs,although various metal ions(Na+,Ca2+,and Al3+)and even organic cations/groups have been explored.Herein,we discuss the advances made more recently,and also the challenges faced by the high‐performance vanadium oxides(V2O5‐based)cathodes,where there are several strategies to improve their electrochemical performance ranging from the new structural designs down to sub‐nano‐scopic/molecular/atomic levels,including cation pre‐intercalation,structural water optimization,and defect engineering,to macroscopic structural modifications.The key principles for an optimal structural design of the V2O5‐based cathode materials for high energy density and fast‐charging aqueous ZIBs are examined,aiming at paving the way for developing energy storage designed for those large scales,high safety,and low‐cost systems.

Combined application of organic manure and chemical fertilizers stabilizes soil N-cycling microflora

Straw and manure are widely applied to agricultural systems,and greatly shape soil N-cycling microflora.However,we still lack a comprehensive understanding of how these organic materials structure soil N-cycling microbial communities.In this study,metagenomic analysis was performed to investigate the compositional variation in N-cycling microbial communities in a 30-year long-term experiment under five fertilization regimes:no fertilization(Control),chemical fertilization only(NPK),and NPK with wheat straw(NPK+HS),pig manure(NPK+PM),and cow manure(NPK+CM).Long-term NPK application differentially changed N-cycling gene abundance and greatly altered N-cycling microbial community structure.NPK+HS resulted in a similar pattern to NPK in terms of gene abundance and community structure.However,NPK+PM and NPK+CM significantly increased most genes and resulted in a community similar to that of the Control.Further analysis revealed that serious soil acidification caused by long-term NPK fertilization was a major factor for the variation in N-cycling microbial communities.The addition of alkaline manure,rather than wheat straw,stabilized the N-cycling microbial community structure presumably by alleviating soil acidification.These results revealed the strong impact of soil acidification on microbial N-cycling communities and illustrated the possibility of resolving nitrogen-related environmental problems by manipulating pH in acidified agricultural soils.

Discovering the relationship of disasters from big scholar and social media news datasets

The construction method for chains of disasters or events is still one of the core scientific questions in studying the common rules of disaster’s evolution.Especially when dealing with the complexity and diversity of disasters,it is critical to make a further investigation on reducing the dependency of prior knowledge and supporting the comprehensive chains of disasters.This paper tries to propose a novel approach,through collecting the big scholar and social news data with disasterrelated keywords,analysing the strength of their relationships with the co-word analysis method,and constructing a complex network of all defined disaster types,in order to finally intelligently extract the unique disaster chain of a specific disaster type.Google Scholar,Baidu Scholar and Sina News search engines are employed to acquire the needed data,and the respectively obtained disaster chains are compared with each other to show the robustness of our proposed approach.The achieved disaster chains are also compared with the ones concluded from existing research methods,and the very reasonable result is demonstrated.There is a great potential to apply this novel method in disaster management domain to find more secrets about disasters.

Highly sensitive active-powering pressure sensor enabled by integration of double-rough surface hydrogel and flexible batteries

A conductive,elastic,and biocompatible hybrid network hydrogel was prepared by cross-linking of locust bean gum,polyvinyl alcohol,and carbon nanotubes,yielding a rough top surface and smooth bottom surface.The merging of the two pieces of hydrogel flat face to flat face forms a highly elastic hydrogel with double-rough surfaces.A piezoresistive sensor assembled with the double-rough surface hydrogel sandwiched between two carbon cloth electrodes exhibits a high sensitivity(20.5 kPa^(-1),0-1kPa),a broad detection range(0.1-100 kPa)and a reliable response for 1000 cycles.The rough contact area between the hydrogels and the carbon cloth is found critical in achieving ultra-high sensitivities in the low-pressure range.Moreover,further monolithic integration of the sensor with a flexible solid-state zinc ion battery ensures the self-powering of the sensor for various human motions detection applications.

Intrinsic physical relationships between rotor modal shapes and instantaneous vibrational energy flow transmission characteristics:Theoretical and numerical analysis and application

The modal vibration of the rotor is the main cause of excessive vibration of the aeroengine overall structure.To attenuate the vibration of the rotor under different modal shapes from the perspective of energy control,the intrinsic physical relationships between rotor modal shapes and instantaneous vibrational energy flow transmission characteristics is derived from the general equation of motion base on the structural intensity method.A dual-rotor-support-casing coupling model subjected to the rotor unbalanced forces is established by the finite element method in this paper.The transmission,conversion and balance relationships of the vibrational energy flow for the rotors in the first-order bending modal shape,the conical whirling modal shape and the translational modal shape are analyzed,respectively.The results show that the vibrational energy flow transmitted to the structure can be converted into the strain energy,the kinetic energy and the energy dissipated by the damping of the structure.The vibrational energy flow transmission characteristics of rotors with different modal shapes are quite different.Especially for the first-order bending modal shape,the vibrational energy flow and the strain energy are transmitted and converted to each other in the middle part of the rotor shaft,resulting in large deformation at this part.To attenuate this harmful vibration,the influences of grooving on the shaft on the first-order bending vibration are studied from the perspective of transmission control of vibrational energy flow.This study can provide theoretical references and guidance for the vibration attenuation of the rotors in different modal shapes from a more essential perspective.

Deformation twinning in equiaxed-grained Fe-6.5 wt.%Si alloy after rotary swaging

Tensile behavior of an equiaxed-grained Fe-6.5 wt.%Si alloy,which was deformed intoφ6 mm bar by hot rotary swaging,was investigated at various temperatures(300–400℃)and stretching rates(0.42–1 mm/min).The results revealed an enhancement in the intermediate-temperature tensile ductility after heat treatments.Deformation twinning was found in the equiaxed-grained Fe-6.5 wt.%Si bars during the tensile test,and heat treatments can enhance the deformation twinning.More twins can be observed in the necking areas than other regions.The high Schmid factor values above 0.4 after heat treatments demonstrated that deformation twinning can easily occur in the equiaxed-grained Fe-6.5 wt.%Si alloy.Higher deformation temperatures,higher strain rates,and larger degree of order suppressed the formation of deformation twinning,while the grain sizes had little effect on the deformation twinning.The twinning stress of the Fe-6.5 wt.%Si alloy increased with the increasing grain size,which did not agree with the Hall–Petch type relationship.The deformation twinning resulted in the improved ductility of the Fe-6.5 wt.%Si alloy.

Venturi-type fluidic sampler for liquid-solid mixtures

Static-type samplers are required for sampling corrosive, toxic, high-temperature, or radioactive liquid-solid fluids. We have designed a compact reverse flow diverter pumping system for transferring liquid-solid mixtures. In accordance with the Venturi principle, an acceptable volume of liquid-solid fluid is automatically collected into a sampling bottle. The effects of sampling needle sizes, sectional area of the T-section, solid concentration, and liquid viscosity on the performance of fluidic samplers were experi- mentally investigated. The sample volume increased upon the reduction of the sampling needle length and the increase of the sectional area of the T-section, but decreased with the increase of solid concentration and liquid viscosity. Unbiased samples of acceptable volume were produced by the proposed fluidic sampler, even at 10.21 mPa s liquid viscosity, 35 wt% solid concentration, and 6.74 m sampling height.

The geochemical evidences of sulphur oil sources in the BZ35/36 structures of the Huanghekou Sag, Bohai Bay Basin, China

Crude oils in the BZ35/BZ36 fields found within the Paleogene Dongying and Shahejie formations in the Huanghekou Sag of the Bohai Bay Basin,China have generally high density,viscosity,and sulfur content.Their physical properties and geochemical features have obvious differences when compared with crude oils from other structures within the Huanghekou Sag.The comparison and analysis of biomarkers(e.g.,pristine/phytane,gammacerane,C24Te/C26TT,C2920S/(20Sþ20R),C29bb/(bbþaa),etc.)show that sour crude oil from the BZ35/BZ36 fields is similar to the sour oil in the Miaoxi Sag adjacent to the eastern of Huanghekou Sag.Sour,low maturity oils in the Miaoxi Sag have likely migrated southwest,while the sweet,higher maturity oils in the Huanghekou Sag have migrated northeast.Crude oils generated from these two sags have focused in the BZ35/BZ36 structures.The source rock of the sour crude oil was most likely formed in a dry climate and strong reducing saline lake.