Fast prototype and rapid construction of three-dimensional and multi-scaled pitcher for controlled drainage by systematic biomimicry

Biomimetic materials that use natural wisdom to solve practical problems are developing rapidly.The trend for systematic biomimicry is towards in-situ characterization of naturalcreatures with high spatial resolutions.Furthermore,rapid reconstruction of digital twin models with the same complex features as the prototype is indispensable.However,it faces bottlenecks and limits in fast characterization and fabrication,precise parameter optimization,geometricdeviations control,and quality prediction.To solve these challenges,here,we demonstrate astate-of-the-art method taking advantage of micro-computed tomography and three-dimensional printing for the fast characterization of the pitcher plant Nepenthes x ventrata and fabrication of its biomimetic model to obtain a superior drainage controller with multiscale structures withprecise surface morphology optimization and geometric deviation control.Thefilm-rupture-based drainage dynamic and mechanisms are characterized by x-ray and high-speed videography,which determines the crucial structures for unique directionaldrainage.Then the optimized artificial pitchers are further developed into sustained drainage devices with novel applications,such as detection,reaction,and smoke control.

Insights into the Origins of Solar-Assisted Electrochemical Water Oxidation in Allotropic Co_(5.47)N/CON Heterojunctions

Solar irradiation can efficiently promote the kinetics of the oxygen evolution reaction(OER)during water splitting,where heterojunction catalysts exhibit excellent photoresponsive properties.However,insights into the origins of photoassisted OER catalysis remain unclear,especially the interfaced promotion under convergent solar irradiation(CSI).Herein,novel allotropic Co_(5.47)N/CoN heterojunctions were synthesized,and corresponding OER mechanisms under CSI were comprehensively uncovered from physical and chemical aspects using the in situ Raman technique and electrochemical cyclic voltammetry method.Our results provide a unique mechanism where high-energy UV light promotes the Co^(3+/4+)conversion process in addition to the ordinary photoelectric effect excitation of the Co^(2+)material.Importantly,visible light under CSI can produce a photothermal effect for Co^(2+)excitation and Co^(3+/4+)conversion,which promotes the OER significantly more than the usual photoelectric effect.As a result,Co_(5.47)N/CoN(containing 28%CoN)obtained 317.9%OER enhancement,which provides a pathway for constructing excellent OER catalysts.

pH和硫酸盐浓度对基因工程菌E.coli FBR5发酵木糖的影响

考察了磷酸缓冲液用量和硫酸钠浓度对基因工程菌E.coliFBR5发酵木糖生成乙醇的影响,发现在添加12mL缓冲液的情况下,木糖利用率最高(为96.5%)。10g/L硫酸钠对发酵速度有一定影响,但对最终乙醇浓度影响不大。20g/L硫酸钠对FBR5的生长和乙醇合成都有明显抑制。

Enhanced mechanical properties and degradation rate of Mg-Ni-Y alloy by introducing LPSO phase for degradable fracturing ball applications

In this work,as-cast Mg-Ni-Y alloys were proposed to develop a feasible material for fracturing balls,and their mechanical performance and corrosion behavior were systematically investigated.Long period stacking order(LPSO)phase was firstly introduced to improve both the mechanical properties and degradation rate of magnesium alloys.With the increase of LPSO phase,the compressive strength was improved significantly,while the elongation of the alloys decreased owing to the relatively brittle nature of LPSO phase.Due to the higher corrosion potential of LPSO phase,the LPSO phase can accelerate the corrosion process by providing more micro-couples.However,the LPSO phase would serve as the corrosion barrier between the corrosion medium and the matrix when the contents of LPSO phase are too high in Mg92.5Ni3Y4.5 and Mg87.5Ni5Y7.5 alloys.As-cast Mg97.5Ni1Y1.5 alloy with satisfactory mechanical properties and rapid degradation rate was successfully developed,exhibiting a high degradation rate of 6675 mm/a(93℃)in 3 wt.%KCl solution and a favorable ultimate compressive strength of 410 MPa.The degradation rate of Mg97.5Ni1Y1.5 alloy is 2-5 times of the current commercial magnesium alloy fracturing materials.

Substitution of Ni for Zn on microstructure and mechanical properties of Mg-Gd-Y-Zn-Mn alloy

This study analyzes the effect of substitution of Ni for Zn on microstructure and mechanical properties of Mg-Gd-Y-Zn-Mn alloy.Our results show that the volume fraction of Mg5(Gd,Y)and(Mg,Zn)3RE phase decreased and LPSO phase increased with more substitution of Ni.After homogenization,onlyα-Mg and LPSO phase existed.In Mg-Gd-Y-Zn-Mn alloys,the LPSO phases mainly consisted of the 14H type.While in Mg-Gd-Y-Ni-Mn alloy,the LPSO phases consisted of the 18R type.In addition,compared with Mg-Gd-Y-Zn-Mn alloy,the mechanical properties of as-extruded Ni-substitution alloys were improved due to the better refinement of the size of grains and LPSO phases.The tensile strength in as-extruded Mg-Gd-Y-Ni-Mn alloy could reach up to 400 MPa with 18%of the elongation to failure.

A Review of Hydrophobic Nanocellulose and Its Applications

Nanocellulose is of great interest in various areas nowadays as a natural nanostructured biomaterial.However,in many applications,the high hydrophilicity due to a large number of hydroxyl groups is not desired.The hydrophobic modification of nanocellulose can thus increase its application.This work reviewed recent developments of methods for nanocellulose hydrophobic modification,through physical adsorption and chemical grafting.The applications of hydrophobic nanocellulose were also reviewed.

Wide-field aurora imager onboard Fengyun satellite:Data products and validation

New observations of auroras based on the wide-field aurora imager(WAI)onboard Fengyun-3D(FY-3D)satellite are exhibited in this paper.Validity of the WAI data is analyzed by comparing auroral boundaries derived from WAI observations with results obtained from data collected by the Special Sensor Ultraviolet Spectrographic Imager(SSUSI)aboard the Defense Meteorological Satellite Program(DMSP F18).Dynamic variations of the aurora with the solar wind,interplanetary magnetic field(IMF)parameters,and the SYM-H index are also investigated.The comparison of auroral boundaries indicates that the WAI data are morphologically valid and suitable to the study of auroral dynamics.Effective responses to solar wind parameters indicate that the WAI data can be useful to monitor and predict the Earth’s space weather.Since the configuration of aurora is a good indicator of the solar wind–magnetosphere–ionosphere(SW-M-I)coupling system,and can reflect the disturbance of the space environment,the WAI will provide important data to help us to study the physical processes in space.

石油管道工程建设企业薪酬管理体系存在的问题及应对思路——以中国石油管道局工程有限公司为例

在总结石油管道工程建设企业薪酬管理体系现状的基础上,分析了企业内部薪酬管理体系存在的问题,主要包括薪酬管理模式僵化、薪酬水平与劳动力市场价位脱轨、绩效薪酬激励导向作用不突出、工资总额分配自主性不强等.以中国石油管道局工程有限公司为例,提出了调整薪酬管理权限、完善薪酬管理体系建设、合理确定基本薪酬等举措,优化了企业的薪酬管理体系.

Review of multimer protein–protein interaction complex topology and structure prediction

Protein–protein interactions (PPI) are important for many biological processes. Theoretical understanding of the structurally determining factors of interaction sites will help to understand the underlying mechanism of protein–protein interactions. At the same time, understanding the complex structure of proteins helps to explore their function. And accurately predicting protein complexes from PPI networks helps us understand the relationship between proteins. In the past few decades, scholars have proposed many methods for predicting protein interactions and protein complex structures. In this review, we first briefly introduce the methods and servers for predicting protein interaction sites and interface residue pairs, and then introduce the protein complex structure prediction methods including template-based prediction and template-free prediction. Subsequently, this paper introduces the methods of predicting protein complexes from the PPI network and the method of predicting missing links in the PPI network. Finally, it briefly summarizes the application of machine/deep learning models in protein structure prediction and action site prediction.

Versatile GaInO_3-sheet with strain-tunable electronic structure,excellent mechanical flexibility,and an ideal gap for photovoltaics

Due to many remarkable physical and chemical properties, two-dimensional(2D) nanomaterials have become a hot spot in the field of condensed matter physics. In this paper, we have studied the structural, mechanical, and electronic properties of the 2D GaInO_3 system by first-principles method. We find that 2D Ga InO_3 can exist stably at ambient condition. Molecular dynamic simulations show that GaInO_3-sheet has excellent thermal stability and is stable up to1100 K. Electronic structural calculations show that GaInO_3-sheet has a band gap of 1.56 eV, which is close to the ideal band gap of solar cell materials, demonstrating great potential in future photovoltaic application. In addition, strain effect studies show that the GaInO_3-sheet structure always exhibits a direct band gap under biaxial compressive strain, and as the biaxial compressive strain increases, the band gap gradually decreases until it is converted into metal. While biaxial tensile strain can cause the 2D material to transform from a direct band gap semiconductor into an indirect band gap semiconductor,and even to metal. Our research expands the application of the Ga InO_3 system, which may have potential application value in electronic devices and solar energy.

Particulate Amines in the Background Atmosphere of the Yangtze River Delta,China:Concentration,Size Distribution,and Sources

Amines are important for new particle formation and subsequent growth in the atmosphere.Consequently,the processes involved are receiving more attention in recent years.Here,we conduct a field observation in order to investigate the atmospheric particulate amines at a background site in the Yangtze River Delta(YRD)during the summer of 2018.Four amines in PM_(2.5),i.e.,methylamine(MA),dimethylamine(DMA),diethylamine(DEA),and trimethylamine(TMA),were collected,twice daily and analyzed.During the campaign,our measurements found the concentrations of MA,DMA,DEA,and TMA of 15.0±15.0,6.3±6.9,20.4±30.1,and 4.0±5.9 ng m^-(3),respectively,and the four amines correlated well with each other.The concentration of amines appear to be independent of whether they were collected during the day or night.Both MA and DMA exhibited a bimodal size distribution that had peaks at 0.67 and 1.1μm,suggesting amines preferably distribute on submicron particles.Boundary layer height(BLH),relative humidity,and pH of aerosols were found have a negative relationship with amines,while aerosol liquid water content(ALWC)was found to have a positive relationship with amines.The PMF(positive matrix factorization)source apportionment results showed that the main source of amines in Chongming Island was of anthropogenic origin such as industrial and biomass emission,followed by marine sources including sea salt and marine biogenic sources.Given that the YRD region is still suffering from complex atmospheric pollution and that the knowledge on aerosol amines is still limited,more field studies are in urgent need for a better understanding of the pollution characteristics of amines.

Analysis of anomalous transport with temporal fractional transport equations in a bounded domain

Anomalous transport in magnetically confined plasmas is investigated using temporal fractional transport equations.The use of temporal fractional transport equations means that the order of the partial derivative with respect to time is a fraction. In this case, the Caputo fractional derivative relative to time is utilized, because it preserves the form of the initial conditions. A numerical calculation reveals that the fractional order of the temporal derivative α(α ∈(0, 1), sub-diffusive regime) controls the diffusion rate. The temporal fractional derivative is related to the fact that the evolution of a physical quantity is affected by its past history, depending on what are termed memory effects. The magnitude of α is a measure of such memory effects. When α decreases, so does the rate of particle diffusion due to memory effects. As a result,if a system initially has a density profile without a source, then the smaller the α is, the more slowly the density profile approaches zero. When a source is added, due to the balance of the diffusion and fueling processes, the system reaches a steady state and the density profile does not evolve. As α decreases, the time required for the system to reach a steady state increases. In magnetically confined plasmas, the temporal fractional transport model can be applied to off-axis heating processes. Moreover, it is found that the memory effects reduce the rate of energy conduction and hollow temperature profiles can be sustained for a longer time in sub-diffusion processes than in ordinary diffusion processes.

A novel two-dimensional SiO sheet with high-stability,strain tunable electronic structure,and excellent mechanical properties

Using the structure search of particle swarm optimization(PSO)algorithm combined with density functional theory(DFT),we conduct a systematic two-dimensional(2D)material research on the SiO and discover a P2 monolayer structure.The phonon spectrum shows that the 2D P2 is dynamic-stable under ambient pressure.Molecular dynamics simulations show that 2D P2 can still exist stably at a high temperature of 1000 K,indicating that 2D P2 has application potential in high-temperature environments.The intrinsic 2D P2 structure has a quasi-direct band gap of 3.2 e V.The 2D P2 structure can be transformed into a direct band gap semiconductor by appropriate strain,and the band gap can be adjusted to the ideal band gap of 1.2 e V–1.6 e V for photovoltaic materials.These unique properties of the 2D P2 structure make it expected to have potential applications in nanomechanics and nanoelectronics.

First-principles study of a new BP_(2)two-dimensional material

Two-dimensional materials have a wide range of applications in many aspects due to their unique properties. Here we carry out a detailed structural search and design of the BP2using the first principles method, and find a new PMM2 sheet.The analysis of the phonon dispersive curves shows that the 2D PMM2 is dynamic stable. The study of molecular dynamics shows that the 2D PMM2 can be stable under high temperature, even at 600 K. Most importantly, when a suitable strain is applied, the structure can exhibit other electronic properties such as direct band gap semiconductor. In addition, the small strain can tune the band gap value of the PMM2 structure to around 1.4 e V, which is very close to the ideal band gap of solar materials. Therefore, the 2D PMM2 may have potential applications in the field of photovoltaic materials.

A hybrid forecasting model for depth-averaged current velocities of underwater gliders

In this paper,we propose a hybrid forecasting model to improve the forecasting accuracy for depth-averaged current velocities(DACVs) of underwater gliders.The hybrid model is based on a discrete wavelet transform(DWT),a deep belief network(DBN),and a least squares support vector machine(LSSVM).The original DACV series are first decomposed into several high-and one low-frequency subseries by DWT.Then,DBN is used for high-frequency component forecasting,and the LSSVM model is adopted for low-frequency subseries.The effectiveness of the proposed model is verified by two groups of DACV data from sea trials in the South China Sea.Based on four general error criteria,the forecast performance of the proposed model is demonstrated.The comparison models include some well-recognized single models and some related hybrid models.The performance of the proposed model outperformed those of the other methods indicated above.

Specifications and control of spatial frequency errors of components in two-beam laser static holographic exposure for pulse compression grating fabrication

The large-aperture pulse compression grating(PCG) is a critical component in generating an ultra-high-intensity, ultra-short-pulse laser;however, the size of the PCG manufactured by transmission holographic exposure is limited to large-scale high-quality materials. The reflective method is a potential way for solving the size limitation, but there is still no successful precedent due to the lack of scientific specifications and advanced processing technology of exposure mirrors. In this paper, an analytical model is developed to clarify the specifications of components, and advanced processing technology is adopted to control the spatial frequency errors. Hereafter, we have successfully fabricated a multilayer dielectric grating of 200 mm × 150 mm by using an off-axis reflective exposure system with Φ300 mm. This demonstration proves that PCGs can be manufactured by using the reflection holographic exposure method and shows the potential for manufacturing the meter-level gratings used in 100 petawatt class high-power lasers.

Status and trends in the stability of the three largest ice shelves in Antarctica

The Ross,Filchner-Ronne,and Amery ice shelves are the three largest ice shelves in Antarctica,playing a crucial role in supporting the Antarctic ice sheet.However,current studies on the stability of the three largest ice shelves primarily focus on singular or limited factors,lacking a comprehensive assessment of multiple parameters.To systematically and in-depth study the stability and trend of the three largest ice shelves,we comprehensively collected and analyzed key parameters,including elevation changes,basal melting,surface meltwater,major rifts propagation rate,suture zones,ice front area change rate,grounding lines,ice velocity,and mass balance.Additionally,we selected the collapsed Larsen B Ice Shelf(LBIS),the rapidly changing and structurally weakened Pine Island Ice Shelf(PIIS),and the accelerating Totten Ice Shelf(TIS)as reference ice shelves.By comparing and analyzing the key parameters between these reference ice shelves and the three largest ice shelves,we find the status and trends in the stability of the latter.Our findings reveal that most key parameters of the three largest ice shelves present relatively minor variations compared to those of the reference ice shelves.Specifically,50%of the parameters are smaller than those of the accelerating TIS,88%are smaller than those of the rapidly changing PIIS,and all parameters are smaller than those of the collapsed LBIS.Furthermore,after analyzing parameters that are not smaller than those of the TIS,it is observed that they remain in a stable state.Hence,the three largest ice shelves are currently undergoing natural changes that do not threaten their stability in the short term.Nevertheless,the evolution of the ice shelves under global climate change remains uncertain,making long-term observation and monitoring essential to assess their impact on sea level rise.

A numerical simulation strategy for a compressor’s underlying axisymmetric characteristic and its application in body force model

Accurate prediction of the aerodynamic response of a compressor under inlet distortion is crucial for next-generation civil aircraft,such as Boundary Layer Ingestion(BLI)silent aircraft.Therefore,research on the Body Force(BF)model plays a significant role in achieving this objective.However,distorted inlet airflow can lead to varying operating conditions across different spatial locations of the compressor,which may cause some regions to operate outside the stability boundary.Consequently,the accuracy of BF model simulations might be compromised.To address this issue,this paper proposes a numerical simulation strategy for acquiring the steady axisymmetric three-dimensional flow field of a compressor operating at low mass flow rates,which is known as the Underlying Axisymmetric Pressure Rise Characteristic(UAPRC).The proposed simulation accounts for two different rotor speeds of a transonic compressor and identifies initial positions in the flow field where deterioration occurs based on prior experimental investigations.Moreover,simulation results are incorporated into the BF model to replicate hub instability observed in experiments.Obtained results demonstrate that this strategy provides valid predictions of the UAPRC of the compressor,thereby addressing the limitations associated with the BF model.

Emission and optical characteristics of brown carbon in size-segregated particles from three types of Chinese ships

Brown carbon(BrC)is one of the important light absorption substances that have high light absorption ability under short wavelength light.However,limit studies have focused on the BrC emission from ships.In this study,size-segregated particulate matters(PM)were collected from three different types of ships,light absorption characteristics and size distribution of methanol-soluble BrC and water-soluble BrC in PM from ship exhausts were investigated.Results showed that four-stroke low-power diesel fishing boat(4-LDF)had the highest mass concentrations of methanol-soluble organic carbon(MSOC)and water-soluble organic carbon(WSOC),followed by 2-stroke high-power heavy-fuel-oil vessel(2-HHV),and fourstroke high-power marine-diesel vessel(4-HMV).While 2-HHV had obviously higher light absorption coefficients of methanol-soluble BrC(Abs365,M)and water-soluble BrC(Abs365,W)in unit weight of PM than the other two types of ships.The tested ships presented comparable or higher absorption efficiency of BrC in water extracts(MAE365,W)compared with other BrC emission sources.Majority of BrC was concentrated in fine particles,and the particle size distributions of both Abs365,Mand Abs365,Wshowed bimodal patterns,peaking at0.43–0.65μm and 4.7–5.8μm,respectively.However,different particle size distributions were found for MAE365,Mbetween diesel and heavy fuel oil ships.Besides,different wavelength dependence in particles with different size were also detected.Ship exhaust could be confirmed as a non-ignorable BrC emission source,and complex influencing factor could affect the light absorption characteristics of ship emissions.Particle size should also be considered when light absorption ability of BrC was evaluated.

Broadband second-harmonic generation in thin-film lithium niobate microdisk via cyclic quasi-phase matching

Whispering-gallery-mode(WGM)microresonators can greatly enhance light-matter interaction,making them indispensable units for frequency conversion in nonlinear optics.Efficient nonlinear wave mixing in microresonators requires stringent simultaneous optical resonance and phase-matching conditions.Thus,it is challenging to achieve efficient frequency conversion over a broad bandwidth.Here,we demonstrate broadband second-harmonic generation(SHG)in the x-cut thinfilm lithium niobate(TFLN)microdisk with a quality factor above 107by applying the cyclic quasi-phase-matching(CQPM)mechanism,which is intrinsically applicable for broadband operation.Broadband SHG of continuous-wave laser with a maximum normalized conversion efficiency of~15%/m W is achieved with a bandwidth spanning over 100 nm in the telecommunication band.Furthermore,broadband SHG of femtosecond lasers,supercontinuum lasers,and amplified spontaneous emission in the telecommunication band is also experimentally observed.The work is beneficial for integrated nonlinear photonics devices like frequency converters and optical frequency comb generator based on second-order nonlinearity on the TFLN platform.