Trifunctional robust electrocatalysts based on 3D Fe/N-doped carbon nanocubes encapsulating Co4N nanoparticles for efficient battery-powered water electrolyzers

Herein,we have designed a highly active and robust trifunctional electrocatalyst derived from Prussian blue analogs,where Co_(4)N nanoparticles are encapsulated by Fe embedded in N-doped carbon nanocubes to synthesize hierarchically structured Co_(4)N@Fe/N-C for rechargeable zinc-air batteries and overall water-splitting electrolyzers.As confirmed by theoretical and experimental results,the high intrinsic oxygen reduction reaction,oxygen evolution reaction,and hydrogen evolution reaction activities of Co_(4)N@Fe/N-C were attributed to the formation of the heterointerface and the modulated local electronic structure.Moreover,Co_(4)N@Fe/N-C induced improvement in these trifunctional electrocatalytic activities owing to the hierarchical hollow nanocube structure,uniform distribution of Co_(4)N,and conductive encapsulation by Fe/N-C.Thus,the rechargeable zinc-air battery with Co_(4)N@Fe/N-C delivers a high specific capacity of 789.9 mAh g^(-1) and stable voltage profiles over 500 cycles.Furthermore,the overall water electrolyzer with Co_(4)N@Fe/N-C achieved better durability and rate performance than that with the Pt/C and IrO2 catalysts,delivering a high Faradaic efficiency of 96.4%.Along with the great potential of the integrated water electrolyzer powered by a zinc-air battery for practical applications,therefore,the mechanistic understanding and active site identification provide valuable insights into the rational design of advanced multifunctional electrocatalysts for energy storage and conversion.

An Investigation of Purely Azimuthal Passive Localization and Position Adjustment in Attempted UAV Formation Flights

When a cluster of unmanned aerial vehicles (UAVs) is flying in formation, it is crucial to maintain the formation and not to be interfered by external electromagnetic wave signals. In order to maintain the formation, this paper proposes to use pure azimuth passive positioning to adjust the position of UAVs, i.e., certain UAVs in the formation transmit signals, the rest of the UAVs receive the signals passively, and extract the orientation information from them to adjust the position of the UAVs [1] [2] [3]. In this paper, the position adjustment problem of UAVs in “circular” formation flight under three models is investigated. To address the problem of “how to obtain the position of the receiving UAV when there are two UAVs with known numbers and evenly distributed on the circumference in addition to the UAV transmitting at the known center of the circle, and the rest of the UAVs with slight deviations in their positions are receiving the signals”, two purely mathematical geometric methods, namely, triangular localization method and polar co-ordinate method, are proposed respectively. We have determined the position of the receiving UAV;we have used the exhaustive method and the construction and disproof method to solve the problem of “how many UAVs are needed to transmit signals in order to realize the effective positioning of the UAVs when it is known that a certain UAV with a slight deviation in its position receives the signals emitted by two UAVs at the same time”, and the results show that: in addition to the known signals emitted by two UAVs, it is also necessary to transmit the signals emitted by two UAVs. The results show that in addition to the known two UAVs transmitting signals, two additional UAVs are required to transmit signals for precise po-sitioning. When the position of UAVs has deviation at the initial moment, the ideal approximation method and the target delimitation method are pro-posed, and the target of nine UAVs uniformly distributed on a circle of a spe-cific radius is achieved through several adjustments, after which the ad-vantages and disadvantages of each model are analyzed, and suggestions for improvement are put forward. The purely azimuthal passive localization method and the constructed model approach proposed in this paper can be extended to other fields, such as spacecraft formations in space and battle-ship formations at sea, as well as other formation flight position adjustment problems.

Design and Analysis of Power and Transmission System of Downhole Pure Electric Command Vehicle

Electric vehicles use electric motors, which turn electrical energy into mechanical energy. As electric motors are conventionally used in all the industry, it is an established development site. It’s a mature technology with ideal power and torque curves for vehicular operation. Conventional vehicles use oil and gas as fuel or energy storage. Although they also have an excellent economic impact, the continuous use of oil and gas threatened the world’s reservation of total oil and gas. Also, they emit carbon dioxide and some toxic ingredients through the vehicle’s tailpipe, which causes the greenhouse effect and seriously impacts the environment. So, as an alternative, electric car refers to a green technology of decarbonization with zero emission of greenhouse gases through the tailpipe. So, they can remove the problem of greenhouse gas emissions and solve the world’s remaining non-renewable energy storage problem. Pure electric vehicles (PEV) can be applied in all spheres, but their special implementation can only be seen in downhole operations. They are used for low noise and less pollution in the downhole process. In this study, the basic structure of the pure electric command vehicle is studied, the main components of the command vehicle power system, namely the selection of the drive motor and the power battery, are analyzed, and the main parameters of the drive motor and the power battery are designed and calculated. The checking calculation results show that the power and transmission system developed in this paper meets the design requirements, and the design scheme is feasible and reasonable.

Stable operation of highly loaded pure Si-Fe anode under ambient pressure via carboxy silane-directed robust solid electrolyte interphase

Incorporation of higher content Si anode material beyond 5 wt% to Li-ion batteries(LIBs)is challenging,owing to large volume change,swelling,and solid electrolyte interphase(SEI)instability issues.Herein,a strategy of diacetoxydimethylsilane(DAMS)additive-directed SEI stabilization is proposed for a stable operation of Si-0.33FeSi_(2)(named as Si-Fe)anode without graphite,which provides siloxane inorganics and organics enrichment that compensate insufficient passivation of fluoroethylene carbonate(FEC)additive and reduce a dependence on FEC.Unprecedented stable cycling performance of highly loaded(3.5 mA h cm^(-2))pure Si-Fe anode is achieved with 2 wt%DAMS combined with 9 wt%FEC additives under ambient pressure,yielding high capacity 1270 mA h g^(-1)at 0.5 C and significantly improved capacity retention of 81% after 100 cycles,whereas short circuit and rapid capacity fade occur with FEC only additive.DAMS-directed robust SEI layer dramatically suppresses swelling and particles crossover through separator,and therefore prevents short circuit,demonstrating a possible operation of pure Si or Sidominant anodes in the next-generation high-energy-density and safe LIBs.

A low-frequency pure metal metamaterial absorber with continuously tunable stiffness

To address the incompatibility between high environmental adaptability and deep subwavelength characteristics in conventional local resonance metamaterials,and overcome the deficiencies in the stability of existing active control techniques for band gaps,this paper proposes a design method of pure metal vibration damping metamaterial with continuously tunable stiffness for wideband elastic wave absorption.We design a dual-helix narrow-slit pure metal metamaterial unit,which possesses the triple advantage of high spatial compactness,low stiffness characteristics,and high structural stability,enabling the opening of elastic flexural band gaps in the low-frequency range.Similar to the principle of a sliding rheostat,the introduction of continuously sliding plug-ins into the helical slits enables the continuous variation of the stiffness of the metamaterial unit,achieving a continuously tunable band gap effect.This successfully extends the effective band gap by more than ten times.The experimental results indicate that this metamaterial unit can be used as an additional vibration absorber to absorb the low-frequency vibration energy effectively.Furthermore,it advances the metamaterial absorbers from a purely passive narrowband design to a wideband tunable one.The pure metal double-helix metamaterials retain the subwavelength properties of metamaterials and are suitable for deployment in harsh environments.Simultaneously,by adjusting its stiffness,it substantially broadens the effective band gap range,presenting promising potential applications in various mechanical equipment operating under adverse conditions.

Strongly Coupled Ag/Sn-SnO_(2)Nanosheets Toward CO_(2)Electroreduction to Pure HCOOH Solutions at Ampere‑Level Current

Electrocatalytic reduction of CO_(2) converts intermittent renewable electricity into value-added liquid products with an enticing prospect,but its practical application is hampered due to the lack of high-performance electrocatalysts.Herein,we elaborately design and develop strongly coupled nanosheets composed of Ag nanoparticles and Sn-SnO_(2) grains,designated as Ag/Sn-SnO_(2) nanosheets(NSs),which possess optimized electronic structure,high electrical conductivity,and more accessible sites.As a result,such a catalyst exhibits unprecedented catalytic performance toward CO_(2)-to-formate conversion with near-unity faradaic efficiency(≥90%),ultrahigh partial current density(2,000 mA cm^(−2)),and superior long-term stability(200 mA cm^(−2),200 h),surpassing the reported catalysts of CO_(2) electroreduction to formate.Additionally,in situ attenuated total reflection-infrared spectra combined with theoretical calculations revealed that electron-enriched Sn sites on Ag/Sn-SnO_(2)NSs not only promote the formation of*OCHO and alleviate the energy barriers of*OCHO to*HCOOH,but also impede the desorption of H*.Notably,the Ag/Sn-SnO_(2)NSs as the cathode in a membrane electrode assembly with porous solid electrolyte layer reactor can continuously produce~0.12 M pure HCOOH solution at 100 mA cm^(−2)over 200 h.This work may inspire further development of advanced electrocatalysts and innovative device systems for promoting practical application of producing liquid fuels from CO_(2).

Method of Electric Powertrain Matching for Battery-powered Electric Cars

The current match method of electric powertrain still makes use of longitudinal dynamics, which can’t realize maximum capacity for on-board energy storage unit and can’t reach lowest equivalent fuel consumption as well. Another match method focuses on improving available space considering reasonable layout of vehicle to enlarge rated energy capacity for on-board energy storage unit, which can keep the longitudinal dynamics performance almost unchanged but can’t reach lowest fuel consumption. Considering the characteristics of driving motor, method of electric powertrain matching utilizing conventional longitudinal dynamics for driving system and cut-and-try method for energy storage system is proposed for passenger cars converted from traditional ones. Through combining the utilization of vehicle space which contributes to the on-board energy amount, vehicle longitudinal performance requirements, vehicle equivalent fuel consumption level, passive safety requirements and maximum driving range requirement together, a comprehensive optimal match method of electric powertrain for battery-powered electric vehicle is raised. In simulation, the vehicle model and match method is built in Matlab/simulink, and the Environmental Protection Agency (EPA) Urban Dynamometer Driving Schedule (UDDS) is chosen as a test condition. The simulation results show that 2.62% of regenerative energy and 2% of energy storage efficiency are increased relative to the traditional method. The research conclusions provide theoretical and practical solutions for electric powertrain matching for modern battery-powered electric vehicles especially for those converted from traditional ones, and further enhance dynamics of electric vehicles.

Space range estimate for battery-powered vertical take-off and landing aircraft

A novel method for estimating the space range of battery-powered vertical take-off and landing(VTOL) aircraft is presented. The method is based on flight parameter optimization and numerical iteration. Subsystem models including required thrust, required power and battery discharge models are presented. The problem to be optimized is formulated, and then case study simulation is conducted using the established method for quantitative analysis. Simulation results show that the space range of battery-powered VTOL aircraft in a vertical plane is an oblate curve, which appears horizontally long but vertically short, and the peak point is not located on the vertical climb path. The method and results are confirmed by parameter analysis and validations.

Analysis of radiometer effect on proof mass in purely gravitational orbit

Spacecrafts with the pure gravity environment are of great significance in precision navigation, gravity field measurement for celestial bodies, and basic physics ex- periments. The radiometer effect is one of the important interfering factors on the proof mass in a purely gravitational orbit. For the gravity field measurement system based on the inner-formation flying, the relationship between the radiometer effect on the inner- satellite and the system parameters is studied by analytical and numerical methods. An approximate function of the radiometer effect suitable for the engineering computation and the correction factor are obtained. The analytic results show that the radiometer effect on the inner-satellite is proportional to the average pressure while inversely pro- portional to the average temperature in the outer-satellite cavity. The radiometer effect increases with the temperature difference in the cavity, and its minimum exists when the cavity radius increases. When the minimum of the radiometer effect arrives, the ratio of the cavity radius to the inner-satellite radius is 1.189 4. This constant is determined by the spherical cavity configuration and independent of the temperature and pressure distributions. When the ratio of the cavity radius to the inner-satellite radius is more than 10, it is believed that the cavity is large enough, the radiometer effect is approxi- mately proportional to the square of the inner-satellite radius, and the influence of the outer-satellite cavity radius on the radiometer effect can be ignored.

Restrictions on Purely Kinetic K-Essence

We restrict purely kinetic k-essence.Assuming that the equation of state is a power law of the kinetic energy,i.e.w=w0Xα,we find thatαmust be positive to obtain accelerated phases,constrained from the conditions for stability and causality.In this case the k-essence behaves like a phantom.We also study the evolutions of the equation of state and the speed of sound with numerical simulations.

Existence of Localized Modes in a Purely Anharmonic Chain

For a monatomic one-dimensional chain of particles interacting via a nearest-neighbor purely anharmonic potential of any even order(such a chain is called purely anharmonic chain),it is proved that there really exist exact localized modes.

Underlying mechanisms of variation in yield asymmetry and strain hardening behavior of extruded pure Mg with Gd addition

Effects of Gd addition on the strain hardening behavior and yield asymmetry of pure Mg are investigated by subjecting extruded pure Mg,Mg–5Gd,and Mg–15Gd(all in wt%)to tension and compression tests along the extrusion direction(ED).As the amount of Gd added to pure Mg increases,the basal texture tilts toward the ED and the distribution of c-axes of grains becomes randomized.Under tension,the strain hardening rates of all the materials decrease until fracture.However,under compression,the strain hardening rate increases in the early stage of deformation in pure Mg and Mg–5Gd,whereas it continuously decreases in Mg–15Gd.Pure Mg exhibits considerably high tension-compression yield asymmetry,with a compressive yield strength(CYS)to tensile yield strength(TYS)ratio of 0.4.In contrast,Mg–5Gd exhibits excellent yield symmetry with CYS/TYS of 0.9 and Mg–15Gd exhibits reversed yield asymmetry with CYS/TYS of 1.2.Underlying mechanisms of these drastically different Gd-addition-induced deformation behaviors of the materials are discussed in terms of the crystallographic distribution of grains and the relative activation stresses of basal slip,prismatic slip,pyramidal slip,and{10–12}twinning under tension and compression.

In Situ Observation of KB_(5) Crystal Growth Under Purely Diffusion Gel Systems by Holographic Interferometry

KB_(5)O_(8).4H_(2)O(KB_(5))crystals have been grown in an agar-agar gel by temperature decrease method for simulating crystal growth in space.Nucleation and growth have been followed by interferometric holography.A concentration field surrounding the growing crystals was obtained and a Liesegang ring was observed.The pattern are visualized directly to reveal physical phenomena of purely diffusion crystal growth kinetics.

Effect of Soursop Puree and Gum Arabic on the Sensory Properties of Non-Dairy Coconut Milk-Based Ice Cream

Coconut (Cocos nucifera) milk-based ice cream is one of the innovative non-dairy milk products gaining popularity among consumers. The objective was to develop coconut milk-based ice cream incorporated with soursop (Annona muricata) fruit puree and gum Arabic from Acacia senegal var. kerensis, conduct a sensory evaluation using descriptive tests by trained panelists (n = 9) then evaluate for consumer acceptability by semi trained panelists (n = 30). A seven-point hedonic scale for colour, taste, flavour, texture and overall acceptability was used. The data obtained was subjected to analysis of variance (ANOVA) and the means were separated to determine their significance differences. Principal Component Analysis (PCA) was done for factor reduction to make it easy for the multi-dimensional descriptive data to be interpreted. PCA results indicated that unit increase in soursop and gum Arabic in the ice cream led to 83.1% increase in starchy taste, 78.3% increase in consistency and 73.6% decrease in coconut aroma. For consumer acceptability test, the obtained results showed that, soursop puree addition at successive levels led to a statistically significant effect (p < 0.05) on colour, flavour, texture, taste and overall acceptability while of gum Arabic incorporation was not significant (p > 0.05) for all attributes. The effect due to interaction between gum Arabic and soursop puree at the different levels however was significant for colour, flavour and texture but not significant for taste and overall acceptability. Our results therefore point to a potential application of soursop fruit and gum Arabic as alternative ingredients in the manufacture of a non-dairy ice cream with desirable sensory properties that would expand the variety of options consumers can choose from.

Tension-Compression Asymmetry in Ultrafine-grained Commercially Pure Ti Processed by ECAP

A homogenous microstructure of ultrafine-grained (UFG) commercially pure (CP) Ti characterized by equiaxed grains/subgrains with an average grain size of about 150 nm and strong prismatic fiber texture were obtained after 4 passes of equal channel angular pressing (ECAP).Tension–compression asymmetry in yield and work hardening behavior of UFG CP Ti were investigated by uniaxial tension and compression tests.The experimental results reveal that UFG CP Ti exhibits a relatively obvious tensioncompression asymmetry in yielding and work hardening behavior.The basal and prismaticslip are suppressed either for tension or compression,which is the easiest to activate.The tension twin system{1012}<1011> easily activated in compression deformation due to the prismatic fiber texture based on the Schmidt factor,consequently resulting in a lower yield strength under compression than tension.ECAP can improve the tension-compression asymmetry of CP Ti due to grain refinement.The interaction among the dislocations,grain boundaries and deformation twins are the main work hardening mechanisms for compression deformation,while the interaction between the dislocations and grain boundaries for tension deformation.Deformation twins lead to the higher work hardening under compression than tension.

Effect of Strain Ratio on Fatigue Model of Ultra-fine Grained Pure Titanium

The ultra-fine grained(UFG)pure titanium was prepared by equal channel angular pressing(ECAP)and rotary swaging(RS).The strain controlled low cycle fatigue(LCF)test was carried out at room temperature.The fatigue life prediction model and mean stress relaxation model under asymmetrical stress load were discussed.The results show that the strain ratio has a significant effect on the low cycle fatigue performance of the UFG pure titanium,and the traditional Manson-coffin model can not accurately predict the fatigue life under asymmetric stress load.Therefore,the SWT mean stress correction model and three-parameter power curve model are proposed,and the test results are verified.The final research shows that the threeparameter power surface model has better representation.By studying the mean stress relaxation phenomenon under the condition of R≠-1,it is revealed that the stress ratio and the strain amplitude are the factors that significantly afiect the mean stress relaxation rate,and the mean stress relaxation model with the two variables is calculated to describe the mean stress relaxation phenomenon of the UFG pure titanium under different strain ratios.The fracture morphology of the samples was observed by SEM,and it was concluded that the final fracture zone of the fatigue fracture of the UFG pure titanium was a mixture of ductile fracture and quasi cleavage fracture.The toughness of the material increases with the increase of strain ratio at the same strain amplitude.

Philosophical Matrix as a System of Categories of Pure Mind

The article is a study devoted to the development of the concept of the philosophical matrix as a system of categories of pure reason.The author proposes a new approach to understanding the philosophical system of categories by putting forward unambiguous comparative concepts that serve as the basis for natural sciences.While the foundations of specific sciences are the concepts of“practical reason”,the author finds the categories of“pure reason”to be the foundations of philosophy,understood as“knowledge of the universal”.The article shows that relying on the senses and the concepts of“practical reason”allows for the verification of knowledge,while their generalization,removed from knowledge obtained empirically,gives categories of“pure reason”,which are accepted as the building material of the matrix.In this way,the author proposes a new system of philosophical categories that describes the fundamental aspects of human reasoning and its interaction with the world.At the same time,the categories of the philosophical matrix are not related to such ambiguous classificatory concepts as space,time,being,existence,consciousness,and others.The article draws attention to the fact that the matrix can be used not only to analyze philosophical theories but also to develop new concrete scientific approaches,for example,for the intellectual development of children.In addition,the article suggests the possibility of applying the philosophical matrix in other areas of the humanities,including psychology,linguistics,and sociology.As a result of the conducted research,the human intellect is divided into three ascending stages,designated by me in the following words-reason,mind,and wisdom,with the subsequent use of these concepts in philosophy and other fields of knowledge.

Optimization of Process Parameters of Continuous Microwave Drying Raspberry Puree Based on RSM and ANN-GA

To improve drying uniformity and anthocyanin content of the raspberry puree dried in a continuous microwave dryer,the effects of process parameters(microwave intensity,air velocity,and drying time)on evaluation indexes(average temperature,average moisture content,average retention rate of the total anthocyanin content,temperature contrast value,and moisture dispersion value)were investigated via the response surface method(RSM)and the artificial neural network(ANN)with genetic algorithm(GA).The results showed that the microwave intensity and drying time dominated the changes of evaluation indexes.Overall,the ANN model was superior to the RSM model with better estimation ability,and higher drying uniformity and anthocyanin retention rate were achieved for the ANN-GA model compared with RSM.The optimal parameters were microwave intensity of 5.53 W•g^(-1),air velocity of 1.22 m·s^(-1),and drying time of 5.85 min.This study might provide guidance for process optimization of microwave drying berry fruits.

基于宏基因组测序和纯培养技术解析胀袋生抽酱油的微生物类群

该研究采用宏基因组测序技术对胀袋生抽酱油微生物类群进行了解析,对其微生物菌株进行了分离鉴定,并对分离株是否可导致酱油胀气进行了验证。宏基因组结果表明,胀袋生抽酱油样品中平均相对含量大于1.0%的微生物主要由嗜盐四联球菌(Tetragenococcus halophilus)、酸鱼联合乳杆菌(Ligilactobacillus acidipiscis)、植物乳植物杆菌(Lactiplantibacillus plantarum)、耐酸乳杆菌(Lactobacillus acetotolerans)、棒状腐败乳杆菌(Loigolactobacillus coryniformis)、短促生乳杆菌(Levilactobacillus brevis)和屎肠球菌(Enterococcus faecium)构成,平均相对含量分别为28.01%、25.50%、9.45%、2.49%、1.83%、1.53%和1.33%;采用纯培养技术,分离出的49株细菌被鉴定为6个属下的11个种,其中枯草芽孢杆菌(Bacillus subtilis)、破布子联合乳杆菌(Ligilactobacillus pobuzihii)、蛋白原酶腐败乳杆菌(Loigolactobacillus rennini)和L.acidipiscis分离株占总分离株数的39.22%、19.61%、11.76%和9.80%,分离出的2株酵母菌均被鉴定为扣囊复膜酵母(Saccharomycopsis fibuligera);产气验证实验发现,所有分离株均不能单独引起生抽酱油的胀袋现象。由此可见,胀袋生抽酱油具有较高的微生物多样性,在后续研究引入培养组学策略以获得更多的分离株,亦或考虑多菌株的协同作用,对酱油涨袋这一产业问题的解决可能具有积极的意义。

基于纯培养和超高深宏基因组测序技术分析茅台镇两企业高温大曲微生物多样性差异

以茅台镇不同酒厂高温大曲为研究对象,采用纯培养技术和宏基因组测序对高温大曲中微生物多样性进行解析。结果发现,分离的212株芽孢杆菌主要为77株索诺拉沙漠芽孢杆菌(Bacillus sonorensis)、39株地衣芽孢杆菌(B. licheniformis)和19株解淀粉芽孢杆菌(B. amyloliquefaciens)等。通过宏基因组Binning技术共获得55个高质量基因组,其中有18个疑似新菌株,分别为Bacillus sp.、Lactobacillus sp.和Weissella sp.等。菌群结构分析表明,高温大曲中的主要菌属分别为Desmospora sp. 8437、B. sonorensis和B. amyloliquefaciens等,其中A酒厂在B. sonorensis和B. amyloliquefaciens等的相对丰度显著较低(P<0.05)。A酒厂高温大曲中微生物的多样性和丰富度均显著低于B酒厂(P<0.05),且两者的菌群结构存在明显的差异。在功能方面,A酒厂高温大曲中丰度较高的差异代谢通路主要与氨基酸的生物合成相关,而B酒厂高温大曲中丰度较高的差异代谢通路主要与L-鼠李糖的降解相关。由此可见,本研究对后续发酵工艺的改良和优良菌株的筛选具有积极意义。