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Electroreduction of CO2 to C2+ products provides a promising strategy for reaching the goal of carbon neutrality. However, achieving high selectivity of C2+ products at high current density remains a challenge. In this work, we designed and prepared a multi‐sites catalyst, in which Pd was atomically dispersed in Cu (Pd−Cu). It was found that the Pd−Cu catalyst had excellent performance for producing C2+ products from CO2 electroreduction. The Faradaic efficiency (FE) of C2+ products could be maintained at approximately 80.8 %, even at a high current density of 0.8 A cm−2 for at least 20 hours. In addition, the FE of C2+ products was above 70 % at 1.4 A cm−2. Experiments and density functional theory (DFT) calculations revealed that the catalyst had three distinct catalytic sites. These three active sites allowed for efficient conversion of CO2, water dissociation, and CO conversion, ultimately leading to high yields of C2+ products. [ABSTRACT FROM AUTHOR]

Electroreduction of CO2 to C2+ products provides a promising strategy for reaching the goal of carbon neutrality. However, achieving high selectivity of C2+ products at high current density remains a challenge. In this work, we designed and prepared a multi‐sites catalyst, in which Pd was atomically dispersed in Cu (Pd−Cu). It was found that the Pd−Cu catalyst had excellent performance for producing C2+ products from CO2 electroreduction. The Faradaic efficiency (FE) of C2+ products could be maintained at approximately 80.8 %, even at a high current density of 0.8 A cm−2 for at least 20 hours. In addition, the FE of C2+ products was above 70 % at 1.4 A cm−2. Experiments and density functional theory (DFT) calculations revealed that the catalyst had three distinct catalytic sites. These three active sites allowed for efficient conversion of CO2, water dissociation, and CO conversion, ultimately leading to high yields of C2+ products. [ABSTRACT FROM AUTHOR]

The lateral vibration of the car body affects the lateral stability of high-speed trains (HSTs), and the aim of this study is to design a good control strategy to decrease the lateral vibration of the car body. First, the Maxwell model of the anti-yaw damper was transformed into a Voigt model by the equivalence method, and a modified 17-degree-of-freedom (DOF) lateral vibration model that includes the anti-yaw damper was established. After the design difficulty and control accuracy of the control strategy were weighed, the lateral and yaw motions of the wheelsets were regarded as disturbances, and a disturbance observer of wheelset motions was designed to simplify the 17-DOF model to a 9-DOF lateral vibration model. Second, a model predictive control (MPC) strategy for HST lateral vibration was designed, and the effects of the key parameters on the lateral vibration acceleration of the HST car body and on the iterative computation time of the MPC strategy were studied. In addition, a conditionally triggered model predictive control (CMPC) strategy was proposed. Last, the control effects of the CMPC strategy under the working conditions of speed change, turnout passage, and aerodynamic load were studied by simulation, which verified the validity of the proposed model and control strategy. [ABSTRACT FROM AUTHOR]

The setting curve and control method of internal temperature in trains are studied in this paper to achieve energy saving control for air conditioning systems. First, a model of interior temperature that considers the heat transmission from infiltration air is established according to the relationship between the equivalent leakage area for the train body and the pressure difference between the internal and external carriage. Second, the interior temperature setting curve, which changes adaptively with the ambient temperature, is established considering the energy consumption of air conditioning systems and passengers' thermal comfort. Finally, an adaptive iterative learning control (AILC) algorithm is proposed and applied to control the interior temperature according to the periodicity of train operation. In this paper, meteorological data from a typical meteorological year are used for simulation analysis. Simulation results show that the AILC algorithm can effectively track the interior temperature setting value and has a better control effect when the train runs on the same line repeatedly. Under the action of the AILC algorithm, the root-mean-square error is reduced to 0.069 °C in the third iteration. Furthermore, the energy saving for a single carriage in a single process reaches up to 1.534 kW·h, thus achieving energy saving control. [ABSTRACT FROM AUTHOR]

For the operational noise of a medium-low speed maglev train, this paper proposes a method to achieve sound source identification based on characteristic frequency extraction and coherence analysis through continuous cross wavelet transform. Field tests were conducted on a main line in China on the operational noise, vibration and traction current of linear induction motor in the medium-low speed maglev train. The proposed method was applied to the test data to analyze the operational noise properties. The characteristic frequencies were extracted from all the three test target signals for coherence analysis through continuous cross wavelet transform, which verifies the transmission characteristics of electromagnetic noise. The coherence spectrum of noise-vibration signal and current-vibration signal showed that the operational noise in the starting and braking stages mainly originates from the high-frequency vibration excited by the high-frequency harmonics in the traction current of the traction motor. [ABSTRACT FROM AUTHOR]

To explore the relationship between the dynamic model parameters of a stabilizing device coupled system and the quality status of a ballast bed, this study establishes a dynamic model of a frame-stabilizing device-rail sleeper system by combining track coupling dynamics with the operating mechanism of a stabilizing device and by using the lumped parameter method. Moreover, by combining the experimental results and nonlinear least squares identification method based on the trust-region reflective algorithm, the mapping relationship between the model parameters and the lateral resistance of the sleeper is discussed. In addition, the dynamic model is validated by numerical simulation using the fourth-order Runge-Kutta method. Results show that the model has good accuracy, and the acceleration peak error rates between the dynamic model response and the test data are all within 5 %; the lateral resistance of the sleeper is positively and negatively correlated with the transverse stiffness and transverse damping of the ballast bed in the system model, and the correlation coefficients are 0.96 and 0.89, respectively. [ABSTRACT FROM AUTHOR]

Electroreduction of CO2 into valuable fuels and feedstocks offers a promising way for CO2 utilization. However, the commercialization is limited by the low productivity. Here, we report a strategy to enhance the productivity of CO2 electroreduction by improving diffusion of CO2 to the surface of catalysts using porous organic cages (POCs) as an additive. It was noted that the Faradaic efficiency (FE) of C2+ products could reach 76.1 % with a current density of 1.7 A cm−2 when Cu‐nanorod(nr)/CC3 (one of the POCs) was used, which were much higher than that using Cu‐nr. Detailed studies demonstrated that the hydrophobic pores of CC3 can adsorb a large amount of CO2 for the reaction, and the diffusion of CO2 in the CC3 to the nanocatalyst surface is easier than that in the liquid electrolyte. Thus, more CO2 molecules make contact with the nanocatalysts in the presence of CC3, enhancing CO2 reduction and inhibiting generation of H2. [ABSTRACT FROM AUTHOR]

Electroreduction of CO2 into valuable fuels and feedstocks offers a promising way for CO2 utilization. However, the commercialization is limited by the low productivity. Here, we report a strategy to enhance the productivity of CO2 electroreduction by improving diffusion of CO2 to the surface of catalysts using porous organic cages (POCs) as an additive. It was noted that the Faradaic efficiency (FE) of C2+ products could reach 76.1 % with a current density of 1.7 A cm−2 when Cu‐nanorod(nr)/CC3 (one of the POCs) was used, which were much higher than that using Cu‐nr. Detailed studies demonstrated that the hydrophobic pores of CC3 can adsorb a large amount of CO2 for the reaction, and the diffusion of CO2 in the CC3 to the nanocatalyst surface is easier than that in the liquid electrolyte. Thus, more CO2 molecules make contact with the nanocatalysts in the presence of CC3, enhancing CO2 reduction and inhibiting generation of H2. [ABSTRACT FROM AUTHOR]

Electrochemical reduction of CO2 by renewable electricity offers a promising way to settle excessive greenhouse gases and achieve carbon neutrality under a mild environment. Cu-based catalysts have a unique catalytic activity towards multicarbon (C2+) products in the CO2 electroreduction reaction and are widely studied to promote the corresponding selectivity and activity. Here we report a F-doped Cu (F–Cu) catalyst to improve C2+ products in CO2 electroreduction. A high C2+ product (mainly ethylene and ethanol) faradaic efficiency of 70.4% was achieved on the F–Cu catalyst with a high current density (above 400 mA cm−2) in the flow-cell system. The in situ surface enhanced Raman spectroscopy results and electrochemical performance analysis demonstrated that CO2 could be reduced into CO at low potentials and the adsorption of CO could be strengthened on F–Cu, which is beneficial to the subsequent C–C coupling step and formation of the C2+ products. [ABSTRACT FROM AUTHOR]

To break through the limitation of conventional iterative learning control algorithm (ILC) that requires a fixed target, a new ILC algorithm is designed for tracking the varying-amplitude but morphologically similar targets. First, the problem is formulated, in which the tracking target is selected as varying-amplitude and biased-measured. Then, the process of the ILC algorithm based on a variable-gain-proportional-integral scheme is discussed, in which the magnitude coefficient is defined and calculated by orthogonal projection and utilised to redefine the error and build the refreshment algorithm of the input. Next, the convergence of the algorithm is analysed and the applicational simulation is conducted. Results show that the new ILC algorithm has the ability in dealing with the trajectory of the varying but morphologically similar target and the applicational scenario of the ILC algorithm is expanded. [ABSTRACT FROM AUTHOR]

Guided by first‐principles calculations, it was found that Cd single‐atom catalysts (SACs) have excellent performance in activating CO2, and the introduction of axial coordination structure to Cd SACs cannot only further decrease the free energy barrier of CO2 reduction, but also suppress the hydrogen evolution reaction (HER). Based on the above discovery, we designed and synthesized a novel Cd SAC that comprises an optimized CdN4S1 moiety incorporated in a carbon matrix. It was shown that the catalyst exhibited outstanding performance in CO2 electroreduction to CO. The faradaic efficiency (FE) of CO could reach up to 99.7 % with a current density of 182.2 mA cm−2 in a H‐type electrolysis cell, and the turnover frequency (TOF) value could achieve 73000 h−1, which was much higher than that reported to date. This work shows a successful example of how to design highly efficient catalysts guided by theoretical calculations. [ABSTRACT FROM AUTHOR]

Guided by first‐principles calculations, it was found that Cd single‐atom catalysts (SACs) have excellent performance in activating CO2, and the introduction of axial coordination structure to Cd SACs cannot only further decrease the free energy barrier of CO2 reduction, but also suppress the hydrogen evolution reaction (HER). Based on the above discovery, we designed and synthesized a novel Cd SAC that comprises an optimized CdN4S1 moiety incorporated in a carbon matrix. It was shown that the catalyst exhibited outstanding performance in CO2 electroreduction to CO. The faradaic efficiency (FE) of CO could reach up to 99.7 % with a current density of 182.2 mA cm−2 in a H‐type electrolysis cell, and the turnover frequency (TOF) value could achieve 73000 h−1, which was much higher than that reported to date. This work shows a successful example of how to design highly efficient catalysts guided by theoretical calculations. [ABSTRACT FROM AUTHOR]

Cuprous oxide catalysts have attracted much attention because they exhibited high selectivity of C2+ products in CO2 electroreduction, but the effect of the structure of catalysts on the reaction needs to be studied further. Herein, we studied the effect of the coordination number (CN) of Cu–Cu and Cu–O in Cu2O on the catalytic performance of CO2 electrocatalytic reduction to C2H4. It was demonstrated that Cu–Cu CN and Cu–O CN, which could be tuned by changing the crystal surface and size of Cu2O, influenced the current density and faradaic efficiency (FE) of C2H4 significantly. At suitable CNs, the FE of C2H4 could reach 50.6% with a current density of 24.5 mA cm−2. [ABSTRACT FROM AUTHOR]

Electroreduction of CO2 to liquid fuels such as ethanol and n‐propanol, powered by renewable electricity, offers a promising strategy for controlling the global carbon balance and addressing the need for the storage of intermittent renewable energy. In this work, we discovered that the composite composed of nitrogen‐doped graphene quantum dots (NGQ) on CuO‐derived Cu nanorods (NGQ/Cu‐nr) was an outstanding electrocatalyst for the reduction of CO2 to ethanol and n‐propanol. The Faradaic efficiency (FE) of C2+ alcohols could reach 52.4 % with a total current density of 282.1 mA cm−2. This is the highest FE for C2+ alcohols with a commercial current density to date. Control experiments and DFT studies show that the NGQ/Cu‐nr could provide dual catalytic active sites and could stabilize the CH2CHO intermediate to enhance the FE of alcohols significantly through further carbon protonation. The NGQ and Cu‐nr had excellent synergistic effects for accelerating the reduction of CO2 to alcohols. [ABSTRACT FROM AUTHOR]

Electroreduction of CO2 to liquid fuels such as ethanol and n‐propanol, powered by renewable electricity, offers a promising strategy for controlling the global carbon balance and addressing the need for the storage of intermittent renewable energy. In this work, we discovered that the composite composed of nitrogen‐doped graphene quantum dots (NGQ) on CuO‐derived Cu nanorods (NGQ/Cu‐nr) was an outstanding electrocatalyst for the reduction of CO2 to ethanol and n‐propanol. The Faradaic efficiency (FE) of C2+ alcohols could reach 52.4 % with a total current density of 282.1 mA cm−2. This is the highest FE for C2+ alcohols with a commercial current density to date. Control experiments and DFT studies show that the NGQ/Cu‐nr could provide dual catalytic active sites and could stabilize the CH2CHO intermediate to enhance the FE of alcohols significantly through further carbon protonation. The NGQ and Cu‐nr had excellent synergistic effects for accelerating the reduction of CO2 to alcohols. [ABSTRACT FROM AUTHOR]

Electroreduction of CO2 to CO powered by renewable electricity is a possible alternative to synthesizing CO from fossil fuel. However, it is very hard to achieve high current density at high faradaic efficiency (FE). Here, the first use of N,P‐co‐doped carbon aerogels (NPCA) to boost CO2 reduction to CO is presented. The FE of CO could reach 99.1 % with a partial current density of −143.6 mA cm−2, which is one of the highest current densities to date. NPCA has higher electrochemical active area and overall electronic conductivity than that of N‐ or P‐doped carbon aerogels, which favors electron transfer from CO2 to its radical anion or other key intermediates. By control experiments and theoretical calculations, it is found that the pyridinic N was very active for CO2 reduction to CO, and co‐doping of P with N hinder the hydrogen evolution reaction (HER) significantly, and thus the both current density and FE are very high. [ABSTRACT FROM AUTHOR]

Electroreduction of CO2 to CO powered by renewable electricity is a possible alternative to synthesizing CO from fossil fuel. However, it is very hard to achieve high current density at high faradaic efficiency (FE). Here, the first use of N,P‐co‐doped carbon aerogels (NPCA) to boost CO2 reduction to CO is presented. The FE of CO could reach 99.1 % with a partial current density of −143.6 mA cm−2, which is one of the highest current densities to date. NPCA has higher electrochemical active area and overall electronic conductivity than that of N‐ or P‐doped carbon aerogels, which favors electron transfer from CO2 to its radical anion or other key intermediates. By control experiments and theoretical calculations, it is found that the pyridinic N was very active for CO2 reduction to CO, and co‐doping of P with N hinder the hydrogen evolution reaction (HER) significantly, and thus the both current density and FE are very high. [ABSTRACT FROM AUTHOR]

Because of the complexity of high-speed train operation, the measured wall pressure of high-speed train will be affected by many factors, such as train vibration and environmental changes, which make the test signal inaccurate. The main interferences are the electromagnetic interference caused by the complicated electromagnetic environment and the sensor output interference caused by the train body vibration. In this paper, ensemble empirical mode decomposition (EEMD) combined with singular value decomposition (SVD) and the local projection de-noise algorithm with better effect on non-linear time series noise reduction are used to eliminate electromagnetic interference in test signal. Because of the frequency band aliasing of test signal and interference cause by vibration, it is difficult to eliminate vibration interference by the signal processing method. In this paper, a vibration interference model is established by model-train experiment and computational fluid dynamics (CFD) software to eliminate the vibration interference in the test signal. Moreover, the theoretical guidance for accurately extracting the wall pressure of high-speed train has been put forward. [ABSTRACT FROM AUTHOR]

Cu(OH)2/CuO nanocomposite-derived Cu2O/Cu was highly efficient for CO2 electroreduction to C2 products. The highest faradaic efficiency and current density could reach 64.5% and 26.2 mA cm−2, respectively. By changing the calcination time, moderate grain boundary density and the Cu+/Cu0 ratio in catalysts can be controlled, leading to a large number of active sites and low interfacial charge transfer resistance. [ABSTRACT FROM AUTHOR]

Bi2WO6 nanosheets with plentiful oxygen vacancies were synthesised, and were highly efficient for the electroredution of CO2 to CO. The faradaic efficiency of CO could reach 91% with a high current density of 43 mA cm−2 at low potentials. The oxygen vacancies could enhance the reaction effectively by improving the adsorption and activation of CO2. [ABSTRACT FROM AUTHOR]

Electrochemical reduction of CO2 into energy‐dense chemical feedstock and fuels provides an attractive pathway to sustainable energy storage and artificial carbon cycle. Herein, we report the first work to use atomic Ir electrocatalyst for CO2 reduction. By using α‐Co(OH)2 as the support, the faradaic efficiency of CO could reach 97.6 % with a turnover frequency (TOF) of 38290 h−1 in aqueous electrolyte, which is the highest TOF up to date. The electrochemical active area is 23.4‐times higher than Ir nanoparticles (2 nm), which is highly conductive and favors electron transfer from CO2 to its radical anion (CO2.−). Moreover, the more efficient stabilization of CO2.− intermediate and easy charge transfer makes the atomic Ir electrocatalyst facilitate CO production. Hence, α‐Co(OH)2‐supported atomic Ir electrocatalysts show enhanced CO2 activity and stability. High‐density atomic Ir supported on α‐Co(OH)2 had outstanding performance for CO2 reduction to CO. The faradaic efficiency can reach 97.6 % with a TOF of 38 290 h−1. The high catalytic activity is attributed to more active sites for CO2 adsorption and activation and the higher efficiency in stabilizing the CO2.− intermediate. [ABSTRACT FROM AUTHOR]

Electrochemical reduction of CO2 into energy‐dense chemical feedstock and fuels provides an attractive pathway to sustainable energy storage and artificial carbon cycle. Herein, we report the first work to use atomic Ir electrocatalyst for CO2 reduction. By using α‐Co(OH)2 as the support, the faradaic efficiency of CO could reach 97.6 % with a turnover frequency (TOF) of 38290 h−1 in aqueous electrolyte, which is the highest TOF up to date. The electrochemical active area is 23.4‐times higher than Ir nanoparticles (2 nm), which is highly conductive and favors electron transfer from CO2 to its radical anion (CO2.−). Moreover, the more efficient stabilization of CO2.− intermediate and easy charge transfer makes the atomic Ir electrocatalyst facilitate CO production. Hence, α‐Co(OH)2‐supported atomic Ir electrocatalysts show enhanced CO2 activity and stability. [ABSTRACT FROM AUTHOR]

B-Doped oxide-derived-Cu is a highly efficient electrocatalyst for transformation of CO2 to C2 products. The faradaic efficiency of C2 products could reach 48.2%, with a high current density of 33.4 mA cm−2 at low potentials in 0.1 M KHCO3 electrolyte. The excellent performance of the catalyst is mainly attributed to Cu+ species stabilized by the introduction of B. [ABSTRACT FROM AUTHOR]

Modulation of the microenvironment on the electrode surface is one of the effective means to improve the efficiency of electrocatalytic carbon dioxide reduction (eCO2RR). To achieve high conversion rates, the phase boundary at the electrode surface should be finely controlled to overcome the limitation of CO2 solubility in the aqueous electrolyte. Herein, we developed a simple and efficient method to structure electrocatalyst with a superhydrophobic surface microenvironment by one‐step co‐electrodeposition of Cu and polytetrafluoroethylene (PTFE) on carbon paper. The super‐hydrophobic Cu‐based electrode displayed a high ethylene (C2H4) selectivity with a Faraday efficiency (FE) of 67.3 % at −1.25 V vs. reversible hydrogen electrode (RHE) in an H‐type cell, which is 2.5 times higher than a regular Cu electrode without PTFE. By using PTFE as a surface modifier, the activity of eCO2RR is enhanced and water (proton) adsorption is inhibited. This strategy has the potential to be applied to other gas‐conversion electrocatalysts. [ABSTRACT FROM AUTHOR]

Modulation of the microenvironment on the electrode surface is one of the effective means to improve the efficiency of electrocatalytic carbon dioxide reduction (eCO2RR). To achieve high conversion rates, the phase boundary at the electrode surface should be finely controlled to overcome the limitation of CO2 solubility in the aqueous electrolyte. Herein, we developed a simple and efficient method to structure electrocatalyst with a superhydrophobic surface microenvironment by one‐step co‐electrodeposition of Cu and polytetrafluoroethylene (PTFE) on carbon paper. The super‐hydrophobic Cu‐based electrode displayed a high ethylene (C2H4) selectivity with a Faraday efficiency (FE) of 67.3 % at −1.25 V vs. reversible hydrogen electrode (RHE) in an H‐type cell, which is 2.5 times higher than a regular Cu electrode without PTFE. By using PTFE as a surface modifier, the activity of eCO2RR is enhanced and water (proton) adsorption is inhibited. This strategy has the potential to be applied to other gas‐conversion electrocatalysts. [ABSTRACT FROM AUTHOR]

Novel porous TiO2@Cu3(BTC)2 composites, which were synthesized using ionic liquids (ILs) as solvents, exhibited excellent activity for photooxidation of styrene to 4-aryl tetralones and promoting the Glaser coupling reaction with O2 under light irradiation. It was discovered that the transformation between Cu2+ and Cu+ was crucial for enhancing the photocatalytic performance. [ABSTRACT FROM AUTHOR]

• New insight for application of SA and its derivatives on storage of fruit and vegetable. • Treatment of SA and derivatives include dipping, coating, fumigating and spraying. • SA and derivatives improve storage quality by inhibiting fruit senescence and CI. • SA and derivatives enhance antioxidant capacity, fruit flavor and pathogen resistance. The applications of salicylic acid (SA) and its derivatives including acetylsalicylate (ASA) and methyl salicylate (MeSA) have been widely used to preserve fruit and vegetables. This paper reviewed recent researches on preharvest and postharvest treatment methods of SA and its derivatives and summaried the effectiveness on postharvest physiological processes of fruit. The preharvest spraying is recommended as the optimal method because of its rapid absorption efficiency of salicylates and the less time of postharvest handing time. Applications of SA and its derivatives have been demonstrated to improve the storage quality by decreasing ethylene production and respiration rate, suppressing fruit softening and color change, keeping the sugars, organic acids and aroma, inhibiting chilling injury, promoting pathogen resistance and activating antioxidant system. The comparison of treatment method and physiological analysis in this review can provide deep insight into practical application of SA and its derivatives on storage of fruit and vegetables. The treatment methods of SA and its derivatives and the effect of maintaining the fruit quality, increasing phenolic compounds and antioxidant capacity, inhibiting biotic and abiotic stresses and keeping the flavor. [Display omitted] [ABSTRACT FROM AUTHOR]

• It exploits the vertical axle-box vibration acceleration signal that it is helpful to simplify the hardware of monitoring system of high-speed train. • The proposed angular synchronous average technique perfectly enhances the fault-related signal of wheel polygon wear by mitigating the asynchronous coherent and random background noise. • The proposed method can detect the order and the rough degree of railway wheel polygonization fault in real-time. The polygon wear of railway wheel (PWRW) is a wear fault that is ubiquitous in railway vehicles. PWRW can induce a strong periodic excitation to both vehicle and track, which not only decreases passenger comfort but also is detrimental to the operational reliability and safety. Both the degree and the order of PWRW are important parameters used to quantify the fault. Because the fault-related components distribute at a wide range in the frequency domain, it is easy to alias with some radiated vibrations from vehicle and track components, which makes the on-board detection for both parameters of PWRW very difficult. To address the practical engineering problem, this paper proposes a detection framework based on the angle domain synchronous averaging technique (ADSAT). The detection method employs the vertical axle-box vibration acceleration (ABVA), which is easy to obtain and can also be used to monitor the conditions of axle-box bearings. The paper compares the proposed and traditional methods. The results reveal that the proposed method not only achieves the order detection which the traditional method cannot, but also mitigates the influence of background noise. The feasibility and effectiveness of the proposed method to improve the detection accuracy of PWRW is demonstrated through simulation and real field investigations. [ABSTRACT FROM AUTHOR]

• Test result of pressure sensor for high speed train will be affected by vibration. • Simulation of actual vibration condition of train body with large mass method. • Simulation of pressure sensor voltage output by electrical structure simulation. • Vibration with same amplitude and different frequency has different influence. • Linear simplified model can accurately calculate vibration effect. This paper devotes to investigate the influence of vibration acceleration on measurement of piezoresistive pressure. For the sake of definiteness, sensor operation conditions in high-speed train are considered. Where, the sensor chip is loaded with dynamic accelerations with frequency within 20 Hz. The real state of the pressure sensor under different frequency vibration load is simulated by using large mass method (LMM). And the voltage output of the pressure sensor under different vibration loads was obtained by the joint simulation of electrical- structure. By analysis of different vibration loads and the voltage output of sensors, their internal relations are obtained. These outcomes provide a guidance for elimination of vibration influence in high-speed train surface fluctuation pressure measurement. It is also useful in other fields of pressure sensor operation in acceleration-loaded environments. [ABSTRACT FROM AUTHOR]

Detached Eddy Simulation (DES) has been used to investigate the effect of the Reynolds number on the wake of a high-speed train in the range from 5.2 ​× ​105 to 2.2 ​× ​107. Then, the characteristics of vortex structure, streamlines distribution, velocity characteristics, and pressure characteristics in the wake region of the high-speed train at five Reynolds numbers are studied. The results show that with the increase of the Reynolds number, some small-scale vortices emerge in the wake region of the high-speed train, which increases the complexity of the wake vortex structure, but the large-scale vortex structure has not changed significantly. The separation lines and vortices distributed on the train surface, and the characteristics of the pressure distribution in the wake region do not change considerably at different Reynolds numbers. The frequency of the vortex shedding from the train based on Strouhal number is approximately a constant at five Reynolds numbers, and the phenomenon and mechanism of the flow in the wake region are almost the same within the range of Reynolds number selected in this study. With the increase of the Reynolds number, the fluctuation degree of the velocity and pressure, and the vorticity in the wake region increase substantially. • DES has been used to investigate the wake characteristics of a high-speed train at five Reynolds numbers. • With the increase of Re , small-scale vortices emerge, but the large-scale vortex structure has not changed significantly. • The separation lines and vortices distributed on the train surface do not change considerably at different Re. • The phenomenon and mechanism of the flow in wake region is almost same within the range of Re from 5.2 × 105 to 2.2 × 107. • With the increase of Re , the fluctuation degree of velocity and pressure, and the vorticity in the wake region increase. [ABSTRACT FROM AUTHOR]

Catalytic conversion of CO2 to produce fuels and chemicals is of great importance, and the electrocatalytic CO2 reduction reaction (eCO2RR) is considered one of the most attractive pathways. Multi-carbon (C2+) products are more desirable in many cases. To date, Cu-based catalysts, especially Cu+ sites, have been found to be the most efficient for the production of C2+ products. However, the retention of Cu+ sites at high cathodic potentials in the eCO2RR remains a great challenge. In this study, we designed and synthesized CuAl-oxide-derived (CuxAly-OD, x and y are the mass percentages of Cu and Al) catalysts for the eCO2RR to C2+ products. During the eCO2RR process, the predominant Cu species changed to Cu+, and the resulting electrocatalyst showed a high faradaic efficiency (FE) of 81.6% for C2+ products in alkaline aqueous solutions. Experimental studies showed that the presence of a stable amorphous Al2O3 phase stabilized the Cu+ sites by oxidation state control, leading to high selectivity and activity for the production of C2+ products. This work provides a strategy for improving the stability of Cu+ in the catalyst to enhance the performance of the eCO2RR. [ABSTRACT FROM AUTHOR]

Electroreduction of CO2 into valuable chemicals and fuels is a promising strategy to mitigate energy and environmental problems. However, it usually suffers from unsatisfactory selectivity for a single product and inadequate electrochemical stability. Herein, we report the first work to use cationic Gemini surfactants as modifiers to boost CO2 electroreduction to formate. The selectivity, activity and stability of the catalysts can be all significantly enhanced by Gemini surfactant modification. The Faradaic efficiency (FE) of formate could reach up to 96 %, and the energy efficiency (EE) could achieve 71 % over the Gemini surfactants modified Cu electrode. In addition, the Gemini surfactants modified commercial Bi2O3 nanosheets also showed an excellent catalytic performance, and the FE of formate reached 91 % with a current density of 510 mA cm−2 using the flow cell. Detailed studies demonstrated that the double quaternary ammonium cations and alkyl chains of the Gemini surfactants played a crucial role in boosting electroreduction CO2, which can not only stabilize the key intermediate HCOO* but also provide an easy access for CO2. These observations could shine light on the rational design of organic modifiers for promoted CO2 electroreduction. [ABSTRACT FROM AUTHOR]

Electroreduction of CO2 into valuable chemicals and fuels is a promising strategy to mitigate energy and environmental problems. However, it usually suffers from unsatisfactory selectivity for a single product and inadequate electrochemical stability. Herein, we report the first work to use cationic Gemini surfactants as modifiers to boost CO2 electroreduction to formate. The selectivity, activity and stability of the catalysts can be all significantly enhanced by Gemini surfactant modification. The Faradaic efficiency (FE) of formate could reach up to 96 %, and the energy efficiency (EE) could achieve 71 % over the Gemini surfactants modified Cu electrode. In addition, the Gemini surfactants modified commercial Bi2O3 nanosheets also showed an excellent catalytic performance, and the FE of formate reached 91 % with a current density of 510 mA cm−2 using the flow cell. Detailed studies demonstrated that the double quaternary ammonium cations and alkyl chains of the Gemini surfactants played a crucial role in boosting electroreduction CO2, which can not only stabilize the key intermediate HCOO* but also provide an easy access for CO2. These observations could shine light on the rational design of organic modifiers for promoted CO2 electroreduction. [ABSTRACT FROM AUTHOR]

Superamphiphilic carbon from sawdust was directly prepared in oxygen/argon. The C element is responsible for the hydrophobic nature and the O element in anhydride and carboxyl groups endows carbon with hydrophilicity. Furthermore, in the oxidation of benzyl alcohol, conversion and yield could reach 94% doubled those of blank experiments in Pickering emulsion due to superamphiphilicity of carbon. [ABSTRACT FROM AUTHOR]

Sn4P3/reduced graphene oxide nanocomposites exhibited high selectivity for CO over a wide potential range from −2.2 V to −2.5 V vs. Ag/Ag+. The maximum faradaic efficiency for CO can reach 96.6% with a high current density of 68.0 mA cm−2. The high efficiency and selectivity can be attributed to the modified electronic structure of Sn sites, the small Sn4P3 nanoparticles and their dense packing in a conductive matrix, leading to a high density of active sites for adsorbing CO2 and stabilizing the CO2˙− intermediate. [ABSTRACT FROM AUTHOR]

The hunting motion of the vehicle increases the wear of the wheel tracks and affects the lateral stability of the vehicle system and safety, so the hunting motion of the vehicle needs to be recognized. However, the existing recognition methods ignore the small-amplitude hunting motion that precedes the onset of the running motion. In addition, due to the scarcity of real hunting data of high-speed trains, there is a problem of underfitting when training with traditional deep learning methods. In this paper, first, the dynamics model of a high-speed train is established, and the normal, small-amplitude hunting and hunting motions of high-speed trains in the process are simulated. Second, this paper proposes a transfer learning-based method for high-speed train hunting motion recognition. The method uses easily collected normal data samples in the training process, does not use real data samples of small-amplitude hunting and hunting motions, and completes the high-speed train running motions recognition task by transferring from simulation data (source domain) to real data (target domain). Finally, the validation is carried out using the real data, which proves that the method-related approach has some engineering application value in the intelligent monitoring of high-speed trains. [ABSTRACT FROM AUTHOR]

MOF-derived In–Cu bimetallic oxides are highly efficient electrocatalysts for the transformation of CO2 into CO in an aqueous electrolyte. By controlling In/Cu ratios, the faradaic efficiency of CO could reach 92.1%. The excellent performance is mainly attributed to stronger CO2 adsorption, higher electrochemical surface area and lower charge transfer resistance. [ABSTRACT FROM AUTHOR]

Ultrathin metal–organic framework (MOF) nanosheets were fabricated by a surfactant-mediated coordination strategy through a pseudo-assembly process. The thickness of the nanosheets could be tuned from 3 nm to 60 nm by varying the hydrophobic chain length of the surfactant. Ru nanoparticles supported on the nanosheets exhibited superior catalytic activity for hydrogenation of levulinic acid to γ-valerolactone. [ABSTRACT FROM AUTHOR]

The gear transmission system is a vital component of the locomotive bogie. During locomotive operation, the damage to the gear transmission system spreads rapidly and affects the locomotive’s operational safety. In this paper, a method is proposed to detect the degree of tooth root crack damage. First, a dynamic locomotive model with a gear transmission is built, and the vertical acceleration of the locomotive subsystem (car body, bogie frame, wheelset, and motor) vibrations is obtained under various degrees of tooth root crack damage on the gear transmission system. By comparing the characteristics of those signals, the subsystem that is more sensitive to the effect of the tooth root crack is found. The characteristic parameters of the sensitive subsystem are calculated, and a multidimensional characteristic parameter matrix is established. The multidimensional characteristic parameter matrix is optimized and reduced by principal component analysis (PCA). Using the Grey relational analysis method, the degree of tooth root crack damage is detected. The proposed method demonstrates the ability to recognize the degree of tooth root crack damage. [ABSTRACT FROM AUTHOR]

Electrochemical reduction reaction of carbon monoxide (CORR) offers a promising way to manufacture acetic acid directly from gaseous CO and water at mild condition. Herein, we discovered that the graphitic carbon nitride (g‐C3N4) supported Cu nanoparticles (Cu−CN) with the appropriate size showed a high acetate faradaic efficiency of 62.8 % with a partial current density of 188 mA cm−2 in CORR. In situ experimental and density functional theory calculation studies revealed that the Cu/C3N4 interface and metallic Cu surface synergistically promoted CORR into acetic acid. The generation of pivotal intermediate −*CHO is advantage around the Cu/C3N4 interface and migrated *CHO facilitates acetic acid generation on metallic Cu surface with promoted *CHO coverage. Moreover, continuous production of acetic acid aqueous solution was achieved in a porous solid electrolyte reactor, indicating the great potential of Cu−CN catalyst in the industrial application. [ABSTRACT FROM AUTHOR]

Electrochemical reduction reaction of carbon monoxide (CORR) offers a promising way to manufacture acetic acid directly from gaseous CO and water at mild condition. Herein, we discovered that the graphitic carbon nitride (g‐C3N4) supported Cu nanoparticles (Cu−CN) with the appropriate size showed a high acetate faradaic efficiency of 62.8 % with a partial current density of 188 mA cm−2 in CORR. In situ experimental and density functional theory calculation studies revealed that the Cu/C3N4 interface and metallic Cu surface synergistically promoted CORR into acetic acid. The generation of pivotal intermediate −*CHO is advantage around the Cu/C3N4 interface and migrated *CHO facilitates acetic acid generation on metallic Cu surface with promoted *CHO coverage. Moreover, continuous production of acetic acid aqueous solution was achieved in a porous solid electrolyte reactor, indicating the great potential of Cu−CN catalyst in the industrial application. [ABSTRACT FROM AUTHOR]

The highly selective aerobic oxidation of cyclohexane to cyclohexanone and cyclohexanol (KA-oil) under benign and green conditions is still a challenging topic. In this work, V2O5@TiO2 catalysts were prepared by V species deposited on TiO2 (P25) and characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), and UV-vis diffuse reflectance techniques. The selective aerobic oxidation of cyclohexane was carried out over V2O5@TiO2 catalysts with oxygen as an oxidant under simulated light irradiation. The influences of solvents, metals and mass of V species deposited on TiO2, pressure of oxygen, and reaction time on the reaction were investigated. It was found that the V species deposited on the TiO2 surface was very efficient for the photocatalytic oxidation of cyclohexane under simulated solar light irradiation. More interestingly, the selectivity of the reaction in an acetonitrile/water mixed solvent was much higher than that in other solvents. Under the optimized conditions, the selectivity to KA-oil products could be nearly 100% at a cyclohexane conversion of 18.9%. The possible pathway for the catalytic reaction was proposed. [ABSTRACT FROM AUTHOR]

Novel durian-like TiO2@CdS core-shell particles were synthesized through a solvothermal method in ethylenediamine solution and the obtained nanocomposites were characterized by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), and transmission electron microscopic (TEM) techniques. It can be seen from the characterization that the synthesized core-shell structured particles show uniform size. The possible formation mechanism of TiO2@CdS core-shell particles is also presented schematically. CdS grows on the TiO2 surface in the form of nanorods, turning the TiO2@CdS composite particles into durian-like structures. The durian-like TiO2@CdS core-shell particles prepared in the experiment can overcome the disadvantages of TiO2 and CdS, respectively. They not only produce a higher yield of H2 than pure TiO2; the durian-like TiO2@CdS nanostructures formed at 180 °C for 16 h produced 2.5 times as much H2 as did TiO2, also showing enhanced stability as compared with pure CdS. [ABSTRACT FROM AUTHOR]

Developing electrocatalytic reactions with high‐efficiency can make important contributions to carbon neutrality. However, poor long‐term stability of catalysts is a bottleneck for its practical application. Herein, an "in situ periodic regeneration of catalyst (PR‐C)" strategy is proposed to give long‐term high efficiency of CO2 electroreduction to generate C2+ products over Cu catalyst by applying a positive potential pulse for a short time periodically in the halide‐containing electrolyte. The high Faradaic efficiency (81.2 %) and current density (22.6 mA cm−2) could be maintained completely at least 36 h, while the activity and selectivity decreased continuously without using the PR‐C method. Control experiments and operando characterization demonstrated that the surface structure and oxidation state of Cu could be recovered periodically by the PR‐C method, which was beneficial for CO2 activation and C−C coupling. [ABSTRACT FROM AUTHOR]

Developing electrocatalytic reactions with high‐efficiency can make important contributions to carbon neutrality. However, poor long‐term stability of catalysts is a bottleneck for its practical application. Herein, an "in situ periodic regeneration of catalyst (PR‐C)" strategy is proposed to give long‐term high efficiency of CO2 electroreduction to generate C2+ products over Cu catalyst by applying a positive potential pulse for a short time periodically in the halide‐containing electrolyte. The high Faradaic efficiency (81.2 %) and current density (22.6 mA cm−2) could be maintained completely at least 36 h, while the activity and selectivity decreased continuously without using the PR‐C method. Control experiments and operando characterization demonstrated that the surface structure and oxidation state of Cu could be recovered periodically by the PR‐C method, which was beneficial for CO2 activation and C−C coupling. [ABSTRACT FROM AUTHOR]

Using renewable electricity to drive CO2 electroreduction is an attractive way to achieve carbon‐neutral energy cycle and produce value‐added chemicals and fuels. As an important platform molecule and clean fuel, methanol requires 6‐electron transfer in the process of CO2 reduction. Currently, CO2 electroreduction to methanol suffers from poor efficiency and low selectivity. Herein, we report the first work to design atomically dispersed Sn site anchored on defective CuO catalysts for CO2 electroreduction to methanol. It exhibits high methanol Faradaic efficiency (FE) of 88.6 % with a current density of 67.0 mA cm−2 and remarkable stability in a H‐cell, which is the highest FE(methanol) with such high current density compared with the results reported to date. The atomic Sn site, adjacent oxygen vacancy and CuO support cooperate very well, leading to higher double‐layer capacitance, larger CO2 adsorption capacity and lower interfacial charge transfer resistance. Operando experiments and density functional theory calculations demonstrate that the catalyst is beneficial for CO2 activation via decreasing the energy barrier of *COOH dissociation to form *CO. The obtained key intermediate *CO is then bound to the Cu species for further reduction, leading to high selectivity toward methanol. [ABSTRACT FROM AUTHOR]

Using renewable electricity to drive CO2 electroreduction is an attractive way to achieve carbon‐neutral energy cycle and produce value‐added chemicals and fuels. As an important platform molecule and clean fuel, methanol requires 6‐electron transfer in the process of CO2 reduction. Currently, CO2 electroreduction to methanol suffers from poor efficiency and low selectivity. Herein, we report the first work to design atomically dispersed Sn site anchored on defective CuO catalysts for CO2 electroreduction to methanol. It exhibits high methanol Faradaic efficiency (FE) of 88.6 % with a current density of 67.0 mA cm−2 and remarkable stability in a H‐cell, which is the highest FE(methanol) with such high current density compared with the results reported to date. The atomic Sn site, adjacent oxygen vacancy and CuO support cooperate very well, leading to higher double‐layer capacitance, larger CO2 adsorption capacity and lower interfacial charge transfer resistance. Operando experiments and density functional theory calculations demonstrate that the catalyst is beneficial for CO2 activation via decreasing the energy barrier of *COOH dissociation to form *CO. The obtained key intermediate *CO is then bound to the Cu species for further reduction, leading to high selectivity toward methanol. [ABSTRACT FROM AUTHOR]

Electrocatalytic reduction of CO2 to a single product at high current densities and efficiencies remains a challenge. However, the conventional electrode preparation methods, such as drop‐casting, usually suffer from low intrinsic activity. Herein, we report a synthesis strategy for preparing heterogeneous electrocatalyst composed of 3D hierarchical Cu dendrites that derived from an in situ electrosynthesized hollow copper metal–organic framework (MOF), for which the preparation of the Cu‐MOF film took only 5 min. The synthesis strategy preferentially exposes active sites, which favor's the reduction of CO2 to formate. The current density could be as high as 102.1 mA cm−2 with a selectivity of 98.2 % in ionic‐liquid‐based electrolyte and a commonly used H‐type cell. [ABSTRACT FROM AUTHOR]

Electrocatalytic reduction of CO2 to a single product at high current densities and efficiencies remains a challenge. However, the conventional electrode preparation methods, such as drop‐casting, usually suffer from low intrinsic activity. Herein, we report a synthesis strategy for preparing heterogeneous electrocatalyst composed of 3D hierarchical Cu dendrites that derived from an in situ electrosynthesized hollow copper metal–organic framework (MOF), for which the preparation of the Cu‐MOF film took only 5 min. The synthesis strategy preferentially exposes active sites, which favor's the reduction of CO2 to formate. The current density could be as high as 102.1 mA cm−2 with a selectivity of 98.2 % in ionic‐liquid‐based electrolyte and a commonly used H‐type cell. [ABSTRACT FROM AUTHOR]

Highlights • The chaotic features of the signals of high speed trains are extracted. • A feature extraction method based on MPE-LTSA is proposed. • The proposed method is also applied to extract features in high speed trains. • This method can be used in other feature recognition for complex chaotic signals. Abstract Hunting stability is an important factor for high-speed trains to achieve safe operation, which can be monitored by on-board instruments. When analysing measured online tracking data of high-speed trains, the authors have observed that small amplitude hunting tend to appear. When these signals show growth of lateral vibration to high enough amplitude, train derailment would happen. Research on the bifurcation evolution of small amplitude hunting of high-speed trains has been rarely reported so far. In this paper, chaotic features of the data are extracted and the results show that lateral acceleration signals from the bogie frame has strong nonlinear characteristics. Then a commonly used method based on frequency distribution characteristics of bogie vibration energy is first used to separate different states of hunting. However, the results are not satisfactory. So a feature extraction method based on Multiscale Permutation Entropy (MPE) and Local Tangent Space Alignment (LTSA) is proposed to distinguish the different states of complex signals. The proposed method is applied to extract features of the small amplitude hunting signals at high-speed of 320–350 km/h. The results show that the MPE-LTSA method can identify the bifurcation evolution of small amplitude hunting signals much more effectively than the method based on the MPE-ISOMAP (Isometric Feature Mapping) and MPE-PCA (Principle Component Analysis). The method can be used in other feature recognition for the complex chaotic signals. [ABSTRACT FROM AUTHOR]