Thin buffer layer assist carbon-modifying separator for long-life lithium metal anodes

The guided Li dendrite growth by carbon-modifying separator is believed to be an effective strategy for enhancing life of lithium metal batteries(LMBs).However,the weak adhesions,as well as the large interface impedance between the smooth separator and the carbon functional layer(CFL) lead to an easily peeling of the CFL after repetitive cycles.Herein,we propose a promising solution by an inserting thin buffer layer(TBL) to strengthen the adhesion between CFL and separator as a double modifying layer(C-TBL) of the LMBs separator,which greatly improves the stability of the CFL and provides an effective Li metal anode protection.Owing to the sufficient ionic conductivity,chemical stability and strong adhesion to the separator of the TBL,it can avoid the failure of the CFL functionality with small interface impedance.Moreover,the CFL effectively reduces localized flux of Li+ through its abundant pores.The Li/Li cell with C-TBL separator displays the Li dendrite-free and stable cycling performance for at least 1500 h.When LiFePO_(4)(LFP) is employed as the cathode electrode,the assembled full cell with C-TBL separator shows the excellent rate performance and outstanding cycling capability.Our study builds a stable Li+conducting "bridge" between the functional layer and the separator in stabilizing Li metal anode,and provides a fresh idea of the artificial separator of LMBs.

A methodology for laser tool setters calibration and its precise mathematical model

On-machine tool setting is a pivotal approach in achieving intelligent manufacturing,and laser tool setters have become a crucial component of smart machine tools.Laser tool setters play a crucial role in precisely measuring the dimensions of cutting tools during the part machining process,focusing on tool length and diameter.As a measuring instrument,the positions of the laser axis of the laser tool setter need to be accurately calibrated before use.However,in actual calibration scenarios,traditional calibration methods face challenges due to installation errors in the tool setter and geometric errors in the measuring rod.To address this issue,this study proposes a novel calibration method.Initially,the calibration mechanism of the laser beam axis is established.Based on the accurate mathematical model of the laser beam and the measuring rod,and using the polygon clipping algorithm,the mathematical mechanism of the laser tool setter’s work is established.Then,a novel method is introduced to calculate the compensation distance between the laser beam reference point and the rod bottom center point at each moment during calibration.Furthermore,by utilizing the kinematic chain of the tool setter calibration system,a new calibration method is developed to accurately calibrate the position of the laser beam axis in the machine tool coordinate system.Finally,the accuracy of the calibration method is verified through simulation experiments and calibration tests.This method improves the calibration accuracy of the tool setter,and the mathematical model of the laser tool setter can be extended to the measurement of tools,thereby improving the precision of tool measurements.This research significantly improves the efficient production performance of smart machine tools.

A customized zeolitic imidazolate framework enabling bionic preconcentration of ultralow CO_(2)

Advancing our understanding of global climate,particularly in polar regions,requires accurate detection of carbon dioxide(CO_(2))in ice cores and deep sea environments.However,detecting trace levels of CO_(2)in these areas presents significant challenges.We introduce a novel preconcentration approach using functionalized zeolitic imidazolate framework,ZIF-8(CN),for the detection of ultra-low CO_(2).ZIF-8(CN)has small pores(4.4■and cyano groups(–CN),enabling highly selective adsorption of CO_(2)(36.2 cm^(3)g^(−1))over N_(2)(1.6 cm^(3)g^(−1))at 298 K.The mechanism involves unique–CN···CO_(2)···–CN interactions within the pore structure.When cast into a film on an aluminum substrate,ZIF-8(CN)demonstrates exceptional CO_(2)preconcentration capability(1 ppm in N_(2))with an extraordinary preconcentration factor of 748,outperforming traditional ZIF and zeolite materials.Additionally,a ZIF-8(CN)preconcentrator is designed and fabricated with bionic gas flow of fractal structure which optimizes the gas-film contact,and thus its performance is further improved by 115%.

A tip clearance prediction model for multistage rotors and stators in aero-engines

Tip clearances of multistage rotors and stators greatly affect aero-engines’ aerodynamic efficiency, stability and safety. The inevitable machining and assembly errors, as well as the complicated error propagation mechanism, cause overproof or non-uniform tip clearances. However, it is generally accepted that tip clearances are difficult to predict, even under assembly state. In this paper, a tip clearance prediction model is proposed based on measured error data. Some 3 D error propagation sub-models, regarding rotors, supports and casings, are built and combined. The complex error coupling relationship is uncovered using mathematical methods. Rotor and stator tip clearances are predicted and analyzed in different phase angles. The maximum, minimum and average tip clearances can be calculated. The proposed model is implemented by a computer program,and a case study illustrates its performance and verifies its feasibility. The results can be referred by engineers in assembly quality judgement and decision-making.

Bionic Optimization Design of Electronic Nose Chamber for Oil and Gas Detection

In this paper, a miniaturized bionic electronic nose system is developed in order to solve the problems arising in oil and gas detection for large size and inflexible operation in downhole. The bionic electronic nose chamber is designed by mimicking human nasal turbinate structure, V-groove structure on shark skin surface and flow field distribution around skin surface. The sensitivity of the bionic electronic nose system is investigated through experimentation. Radial Basis Function （RBF） and Support Vector Machines （SVM） of 10-fold cross validation are used to compare the recognition performance of the bionic electronic nose system and common one. The results show that the sensitivity of the bionic electronic nose system with bionic composite chamber （chamber B） is significantly improved compared with that with common chamber （chamber A）. The recognition rate of chamber B is 4.27% higher than that of chamber A for the RBF algorithm, while for the SVM algorithm, the recognition rate of chamber B is 5.69% higher than that of chamber A. The three-dimensional simulation model of the chamber is built and verified by Computational Fluid Dynamics （CFD） simulation analysis. The number of vortices in chamber B is fewer than that in chamber A. The airflow velocity near the sensors inside chamber B is slower than that inside chamber A. The vortex intensity near the sensors in chamber B is 2.27 times as much as that in chamber A, which facilitates gas molecules to fully contact with the sensor surface and increases the intensity of sensor signal, and the contact strength and time between odorant molecules and sensor surface. Based on the theoretical investigation and test validation, it is believed that the proposed bionic electronic nose system with bionic composite chamber has potential for oil and gas detection in downhole.

Design and Experiments of Biomimetic Stubble Cutter

The fore claws of the nymph of Cryptotympana atrata have excellent ability to cut and dig soil. Inspired by this, we designed a biomimetic stubble cutter to reduce the cutting resistance. Reverse engineering and 3D print technology were applied to design the biomimetic stubble cutter. Two types of biomimetic corn stubble cutters with different tooth heights （5 mm and 2.5 mm） were designed. The cutting ability of biomimetic corn stubble cutters was compared to the conventional design by the quadratic regression orthogonal test. Tooth height, dip angle of cutting edge, and cutting velocity were chosen as orthogonal test factors. The biomimetic stubble cutters show lower cutting resistance than the conventional one. Cutting velocity exerts the least effect on cutting resistance, followed by tooth height and dip angle of cutting edge. Optimal combination with the least cutting resistance is tooth height of 2.5 mm and dip angle of cutting edge of 40° while the cutting resistance does not vary remarkably with cutting velocity. Test results indicate the serrated structure design as a principal factor for cutting resistance reduction. The biomimetic stubble cutter design, inspired by the soil-cutting mechanism of Cryptotympana atrata nymph, remarkably improves the performance of stubble cutter.

An Optimal Wet Friction Plate Inspired by Biological Surface Patterns

It is found that many biological organisms exhibit superior adhesion characteristics in wet environments. It has been observed that the foot pads of tree frogs and katydids are consist of a number of closely arranged polygons, most of them are hexagonal. In this paper, the common structure of two kinds of biological foot pad was extracted to model the bionic surface structure of friction plates. The friction plate prototypes were also prepared. Through the multivariate orthogonal regression design, the optimum parameter combination of the friction performances of the prototypes of the bionic plates has been obtained. The hexagonal circumcircle size is 10 mm, the groove width is 1 mm, and the hexagonal diagonal angle is 90~. Then the maximum static friction coefficient, dynamic friction coefficient and wear amount of the optimal friction plate were tested and compared with the control group friction plates. The comparative analysis of the experiment findings demonstrated that the bionic structure with hexagonal ring grooves can significantly improve the friction performance of the friction plates.

Inspired by Tree Frog:Bionic Design of Tread Pattern and Its Wet Friction Properties

The wet grip of tire has always been the focus because it is related to the personal safety of passengers directly.Many methods were employed to improve the wet grip of tire.Researchers paid more attention on bionics method recent years.In nature,tree frogs have high adhesion ability in wet environment,which is mainly due to their footpads having fine polygon grooves(mainly hexagon grooves).To improve the performance of wet grip of tire,from the perspective of bionics,inspired by the footpad of tree frog,the bionic hexagon tread pattern was designed.The friction test was carried out to compare with the common tread patterns such as serrated,striped and square patterns.The results showed that the bionic hexagon tread pattern generally had high friction coefficient and directional stability of friction.The main reason was that the hexagon tread block was less affected by the friction-induced torque and the groove of bionic hexagon tread pattern had better drainage characteristic.The bionic hexagon tread pattern provides new idea and method for the design of tires with high wet grip.

Brain-like Intelligent Decision-making Based on Basal Ganglia and Its Application in Automatic Car-following

The anthropomorphic intelligence of autonomous driving has been a research hotspot in the world.However,current studies have not been able to reveal the mechanism of drivers'natural driving behaviors.Therefore,this thesis starts from the perspective of cognitive decision-making in the human brain,which is inspired by the regulation of dopamine feedback in the basal ganglia,and a reinforcement learning model is established to solve the brain-like intelligent decision-making problems in the process of interacting with the environment.In this thesis,first,a detailed bionic mechanism architecture based on basal ganglia was proposed by the consideration and analysis of its feedback regulation mechanism;second,the above mechanism was transformed into a reinforcement Q-learning model,so as to implement the learning and adaptation abilities of an intelligent vehicle for brain-like intelligent decision-making during car-following;finally,the feasibility and effectiveness of the proposed method were verified by the simulations and real vehicle tests.

Bio-inspired Design and Evaluation of Porous Fences for Mitigating Fugitive Dust

Fugitive dust has been recognized as an important contributor to air pollution,and artificial porous fence is one of the most effective management strategies to reduce fugitive dust in open areas.To improve the shelter effects and efficiency of Particulate Matter(PM)reduction of traditional fences,this study proposed five bionic fences and their capability was evaluated through wind tunnel tests.The results indicated that all of bionic fences presented better efficiency in reducing wind speed and PM concentrations compared with traditional fences,and they were more efficient in capturing PM10.Among the bionic fences,the non-woven cloth material with four-leave opening presented the best capability both in wind speed and PM reduction.The proposed bionic fences may be further developed and studied for future application in capturing fine PM and adapting to the wind.

Bionic Design to Reduce Jacking Force for Trenchless Installations in Clay Soil

The application of trenchless technology is the trend of underground public facilities'installation,replacement and repairing.As the soil-engaging component during penetrating bore,the working resistance of penetration head has remarkable effect on energy consumption of the whole working process.Some typical soil-digging animals,like pangolin and earthworm,they own special micro structures on their surface.It has been widely proved that some micro geometrical structures can effectively reduce adhesion resistance.Four kinds of bionic penetration heads were designed by imitating micro geometrical structures inspired by the soil animals.In this work,the real time jacking forces of the bionic penetration heads were measured and compared with a smooth penetration head(control group)without micro geometrical structures.The result indicated that the jacking forces of the bionic penetration heads were smaller than that of the smooth penetration head.This proved that the bionic penetration heads have the ability of reducing adhesion resistance.The vertical concave penetration head got the smallest jacking force,of which the average jacking force was 18.7%lower than that of the smooth penetration head.The interaction between soil and bionic surface of penetration head was discussed on the condition of wet friction.The bionic surface reduced the adhesion resistance by disturbing the soil and braking the continuous water film between soil and the surface of the penetration head.

A new localization theory of adaptive machining of near-net-shape blades

In the fabrication of aero-engine blades,a great deal is gained when massive material removal is avoided at the end of the process,and as little as possible material is left on the blade billet.Due to the uncertainty of pre-process,the billet shapes are inconsistent.Sometimes,the near-net-shape billet doesn’t cover the blade design surface to be cut.Therefore,blade localization is necessary for these billets before the machining.In conventional localization methods,the design surface’s location focused on guaranteeing enough material to be cut.However,because the to-becut surface is in near-net and free-form shape,it is difficult to find a valid localized surface model to generate the tool path.Different from the localized surface is taken as rigid in previous investigation,it is allowed to deviate from the design surface no more than the tolerance band.In term of this principle,the tolerance band is utilized to promote localization ability.A series of optimization models with different priorities is established to avoid the abandonment expensive blade billet.Finally,with the experiments performed on the near-net-shape blades,the blade localization theory and the promotion of localization ability are verified.

Bionic Layout Optimization of Sensor Array in Electronic Nose for Oil Shale Pyrolysis Process Detection

In order to meet the requirements for miniaturization detection of oil shale pyrolysis process and solve the problem of low sensitivity of oil and gas detection devices,a small bionic electronic nose system was designed.Inspired by the working mode of the olfactory receptors in the mouse nasal cavity,the bionic spatial arrangement strategy of the sensor array in the electronic nose chamber was proposed and realized for the first time,the sensor array was used to simulate the distribution of mouse olfactory cells.Using 3D printing technology,a solid model of the electronic nose chamber was manufactured and a comparative test of oil shale pyrolysis gas detection was carried out.The results showed that the proposed spatial arrangement strategy of sensor array inside electronic nose chamber can realize the miniaturization of the electronic nose system,strengthen the detection sensitivity and weaken the mutual interference error.Moreover,it can enhance the recognition rate of the bionic spatial strategy layout,which is higher than the planar layout and spatial comparison layout.This bionic spatial strategy layout combining naive bayes algorithm achieves the highest recognition rate,which is 94.4%.Results obtained from the Computational Fluid Dynamics(CFD)analysis also indicate that the bionic spatial strategy layout can improve the responses of sensors.

Detection and classification of pesticide residues in dandelion(Taraxacum officinale L.)by electronic nose combined with chemometric approaches

In this study,for the first time a suitable pesticide residue detection system for dandelion(Taraxacum officinale L.)was established based on electronic nose to determine and study the concentration of pesticide residue in dandelion.Dandelions were sprayed with different concentrations of pesticides(avermectin,trichlorfon,deltamethrin,and acetamiprid),respectively.Data collection was performed by application of an electronic nose equipped with 12 metal oxide semiconductor(MOS)sensors.Data analysis was conducted using different methods including BP neural network and random forest(RF)as well as the support vector machine(SVM).The results showed the superior effectiveness of SVM in discrimination and classification of non-exceeding maximum residue limits(MRLs)and exceeding MRLs standards.Moreover,the model trained by SVM has the best performance for the classification of pesticide categories in dandelion,and the classification accuracy was 91.7%.The results of this study can provide reference for further development and construction of efficient detection technology of pesticide residues based on electronic nose for agricultural products.

A Bionic Degassing Device Inspired by Gills:Application on Underwater Oil and Gas Detection

Over the past decades,membrane-based separation processes have found numerous applications in various industries.Membrane contactor is an important part of the separation of dissolved gas in the early stage of gas detection.In this paper,to improve efficiency in the detection of the dissolved gas phase in seawater,a better flat membrane contactor is proposed to achieve efficient degassing,inspired by the way fish breathe underwater and the special structure of fish gills.The bioinspired flow channel structures in the flat membrane contactor are suggested along with the distribution of internal blood vessels in the gill platelet and the feature of the gill platelet surface.Using 3D printing,the special degassing devices are manufactured,and comparative analysis of relevant flow parameters is made using different flow channels,combined with the CFD simulation.The final result showed that the proposed flow channel in the degasser achieves a better degassing effect compared with conventional flow channel when the membrane contact area is limited,which can provide good conditions for subsequent gas detection.