Small Density Research Articles

Interplay of quantum spin Hall effect and spontaneous time-reversal symmetry breaking in electron-hole bilayers. I. Transport properties

The band-inverted electron-hole bilayers, such as InAs/GaSb, are an interesting playground for the interplay of quantum spin Hall effect and correlation effects because of the small density of electrons and holes and the relatively small hybridization between the electron and hole bands. It has been proposed that Coulomb interactions lead to a time-reversal symmetry broken phase when the electron and hole densities are tuned from the trivial to the quantum spin Hall insulator regime. We show that the transport properties of the system in the time-reversal symmetry broken phase are consistent with recent experimental observations in InAs/GaSb. Moreover, we carry out a quantum transport study on a Corbino disk where the bulk and edge contributions to the conductance can be separated. We show that the edge becomes smoothly conducting and the bulk is always insulating when one tunes the system from the trivial to the quantum spin Hall insulator phase, providing unambiguous transport signatures of the time-reversal symmetry broken phase.

Dynamics of a Discrete Lotka–Volterra Information Diffusion Model

To explore the process of online social network information interaction, in this paper, we analyze the dynamics of a discrete Lotka–Volterra information diffusion model. Using the center manifold theorem, the conditions for transcritical bifurcation and flip bifurcation are obtained. With the help of approximation by a flow and Picard iteration, we explore the qualitative structures and stability of degenerate fixed point of the model with eigenvalues [Formula: see text]. What’s interesting is that our results reveal a new and complex qualitative structure for fixed point, which are different from the previous reports and called degenerate saddle point. Additionally, the qualitative structures provide a new idea for investigation the stability of degenerate fixed point. Meanwhile, near the maximum user density, the dynamic results of degenerate fixed point indicate that if the intervention rate is greater than the inverse of the maximum user density, then the higher user density decreases, the lower user density increases when intrinsic growth rates are small (between 0 and 2). However, when the intrinsic growth rate is greater than 2, the high user density will continue to increase until it approaches the maximum user density indefinitely, while the small user density will approach 0, which provide us with new insights into information diffusion. Finally, we show the results of the model by numerical simulations, and the characteristics of information diffusion near the degenerate fixed point are predicted by theoretical analysis.

On the energy transport and heat transfer efficiency in radiatively heated particle-laden Rayleigh–Bénard convection

We investigate the energy transport and heat transfer efficiency in turbulent Rayleigh–Bénard (RB) convection laden with radiatively heated inertial particles. Direct numerical simulations combined with the Lagrangian point-particle mode were carried out in the range of density ratio $854.7\le \rho _p/\rho _0 \le 8547$ and radiation intensity $1\le \phi /\phi _{solar}\le 100$ for both two-dimensional (2-D) and three-dimensional (3-D) simulations. The Rayleigh number ranges from $2\times 10^6$ to $10^8$ for 2-D cases, and is $10^7$ for 3-D cases for $Pr=0.71$ . It is found that particles with small density ratio that encounter strong radiation significantly alter the flow momentum transport and fluid heat transfer, so the fluid temperature of bulk is remarkably heated. We then derived the theoretical relation of the Nusselt number for interphase heat transfer in the heated particle-laden RB convection, which reveals that the heat transfer difference between the top and bottom plates stems from the interphase heat transfer. We further found that both the interphase heat transfer and the interphase thermal energy transport exhibit universal properties. They are both increased linearly with the reciprocal of the normalized density ratio. Additionally, both the interphase heat transfer and the interphase thermal energy transport increase linearly with the increase of radiation intensity. The growth rates exhibit specific scaling relations versus Rayleigh number and density ratio. Two different regimes distinguished by the critical density ratio, i.e. the exothermic particle regime and the endothermic particle regime, are observed. We further derived the power-law relation of the critical density ratios versus Rayleigh number and radiation intensity, i.e. $\rho _p/\rho _c \sim (\phi /\phi _{solar})^{1/2}\,Ra^{1/3}$ , which is in remarkable agreement with the 3-D simulations.

Effect of aging temperature on microstructure and mechanical properties of laser melted and hot isostatically pressed (CoCrFeMnNi)96(TiAl)4 alloy

In this study, a selectively laser melted (SLM) and hot isostatically pressed (HIPed) high entropy alloy (HEA), (CoCrFeMnNi)96(TiAl)4, was aged at different temperatures to investigate the microstructural evolution and mechanical property development with the aim of identifying the optimum aging condition that can produce the best combination of tensile properties for the alloy. It was found that the SLM-HIPed HEA contains a small density of nano-sized Al2O3 and σ particles. Upon aging at relatively low temperatures (650 °C and 700 °C), a high density of nano-sized long-range ordered (LRO) L12 domains formed from the matrix. Heusler and B2 particles also started to form from the matrix. With increased aging temperature, both the area fractions and sizes of Heusler, B2 and σ particles increased continuously. Aging at 750 °C gave rise to no LRO L12 domains but γ′ particles while aging at 800 °C led to disappearance of both LRO domains and γ′. The formation of Heusler and B2 precipitates was found to be associated with the diffusion of Al, Ti and Ni while that of σ is linked to the diffusion of Cr. Increased precipitation of Heusler and B2 with increased aging temperature was accompanied by the disappearance of LRO L12 domains, suggesting that the former may have competed with the latter in terms of absorption of Ni, Ti and Al. The samples containing LRO L12 domains and fine precipitates show the highest 0.2% yield strength (YS>610 MPa) and ultimate tensile strength (UTS>960 MPa) while maintaining a high elongation (EL>25%). Those that are free of LRO L12 domains and contain large Heusler, B2 and σ particles show much lower YS (∼490 MPa) and UTS (760–850 MPa) as well as reduced ductility. The results indicate that the formation of LRO L12 domains is crucial for acquisition of enhanced YS in the HEA. In the early stage of plastic deformation, paired dislocations were found to shear through the LRO L12 domains and with increased strains, a number of stacking faults formed with many of them intersecting with each other to form Lomer-Cottrell locks which favoured strain hardening. Dislocations tended to loop around Al2O3, Heusler and σ precipitates, indicating that they can act as effective dislocation motion obstacles.

A Comparison between Statistical Behaviours of Scalar Dissipation Rate between Homogeneous MILD Combustion and Premixed Turbulent Flames

Three-dimensional Direct Numerical Simulations (DNS) data has been utilised to analyse statistical behaviours of the scalar dissipation rate (SDR) and its transport for homogeneous methane-air mixture turbulent Moderate or Intense Low oxygen Dilution (MILD) combustion for different O2 dilution levels and turbulence intensities for different reaction progress variable definitions. Additional DNS has been conducted for turbulent premixed flames and passive scalar mixing for the purpose of comparison with the SDR statistics of the homogeneous mixture MILD combustion with that in conventional premixed combustion and passive scalar mixing. It has been found that the peak mean value of the scalar dissipation rate decreases with decreasing O2 concentration for MILD combustion cases. Moreover, SDR magnitudes increase with increasing turbulence intensity for both MILD and conventional premixed combustion cases. The profiles and mean values of the scalar dissipation rate conditioned upon the reaction progress variable are found to be sensitive to the choice of the reaction progress variable definition. This behaviour arises due to the differences in the distributions of the species mass fractions within the flame. The strain rate contribution and the molecular dissipation term are found to be the leading order contributors in the scalar dissipation rate transport for MILD combustion; whereas, in conventional premixed flames, the terms rising from density variation and reaction rate gradient also play leading roles in addition to the strain rate and molecular dissipation contributions. By contrast, the terms due to density gradient and reaction rate gradient remain negligible in comparison to the leading order contributors in MILD combustion cases due to small density variation because of moderate temperature rise and small reaction rate gradient magnitudes. Furthermore, the qualitative behaviour of the strain rate contribution to the SDR transport in premixed flames is significantly different to that in the case of MILD combustion and passive scalar mixing. The findings of the current analysis indicate that the scalar dissipation rate statistics in MILD combustion show several qualitative similarities to the passive scalar mixing despite major differences with the SDR transport in conventional turbulent premixed flames. This further suggests that the scalar dissipation rate models, which were originally proposed in the context of passive scalar mixing, have the potential to be applicable for MILD combustion but the models for the premixed turbulent combustion may not be applicable for MILD combustion of homogeneous mixtures.

Call rate as an index of nest count in wading bird colonies

Traditional monitoring methods for colonial waterbirds, such as nest counts, can be expensive, time‐intensive, disruptive to nesting birds and limited by colony accessibility. Our study tested the use of acoustic sampling as a colony monitoring technique for three species of colonially nesting herons (Ardeidae) by quantifying the relationship between chick call rate and nest count in colonies. Because acoustic detection can be influenced by soundscape variables, we measured day since colony initiation, body condition index of small heron chicks, nest height, vegetation density and wind speed and evaluated their effects on call rate detection. Generalized linear mixed‐effects models showed that call rate detection increased with daily nest count for all species. Snowy Egret Egretta thula and Tricoloured Heron Egretta tricolour detected call rate was also dependent on environmental, temporal and physiological variables, whereas Great Egret Ardea alba call detection was affected by vegetation density around nests and wind speed. Our study showed that wading bird nest counts can be estimated using acoustic sampling, reducing the need for manual colony surveys, and facilitating long‐term monitoring of wading bird nesting trends, which are important measures of wetland restoration worldwide.

유리섬유 강화 플라스틱 성형에서 유리섬유의 단면형상과 사출조건이 인장강도에 미치는 영향

SFT, which has a high glass fiber content, is one of the effective methods to replace metal and secure weight reduction and price competitiveness. This study evaluated the effect of glass fiber shape on mechanical properties in injection molding by fabricating SFT with a glass fiber content of 60%. Three types of SFTs were manufactured by adding round glass fibers of Φ7 μm and Φ10 μm and flat glass fibers of 27 × 10 μm. DOE (Design of Experiment) conducts to confirm the change in tensile strength due to changes in significant injection conditions. As a result of the experiment, Φ7 μm SFT and flat SFT have similar tensile strength and Φ10 μm SFT showed the lowest tensile strength value. As for the standard deviation of strength value, the Φ7 μm SFT had the largest standard deviation, and the Φ10 μm SFT showed the slightest change in the injection conditions. In flat SFT, it confirms that the tensile strength increased as the molding temperature increased. The fracture surface observes using SEM. It founds that the tensile strength lowers due to the small glass fiber density and many pullouts at the fracture surface of Φ10 μm with weak strength.

Polygon-Retrofitted Integrated Modular Motor Drive for Switched Reluctance Machines

Thanks to the absence of rotor windings and permanent magnets, switched reluctance motors have a small weight construction. The integration of a modular power converter in a switched reluctance motor leads to a highly compact and fault-tolerant motor drive with small weight and high power density. In this article, a polygon-retrofitted integration topology is proposed for switched reluctance motors. Both the switched reluctance motor and the power converter are cooled with one shared cooling circuit. The power converter is designed and implemented using silicon carbide technology for its low losses and small thermal resistance. The proposed integration topology is extensively studied using multiphysics modeling and experimental measurements on a fully integrated rotating setup. A highly compact and power dense drive of 3.1 kW/L is obtained.

Ceramic nanoparticles enhancement of latent heat thermal energy storage properties for LiNO3/NaCl: Evaluation from material to system level

Focusing on the development of the next generation latent heat thermal energy storage (TES), molten salt is one of the most promising candidates, while it suffers from small thermal charging rate and low energy storage density. Adding ceramic nanoparticles (NPs) with high thermal conductivity and high chemical stabilities has been proposed to alleviate above problems. However, it’s very challenging to enhance both thermal conductivity and specific heat capacity (Cp) simultaneously. Besides, induced viscosity increment by NPs will instead reduce the thermal charging rate of TES system, due to suppressed natural convection of molten salts. Herein, concurrent enhancement in solidus thermal conductivity and Cp is demonstrated by doping MgO NPs into LiNO3/NaCl, which are improved by 63.5 % and 32.3 % at 4 wt%, respectively. The underlying mechanism is attributed to very low interfacial thermal resistance (Rb = 2.424 × 10−9 K·m2·W−1) between MgO and LiNO3/NaCl. Benefiting from enhanced Cp, the total energy storage density increases from 662.9 J·g−1 to 671.7 J·g−1 for temperature range of 50–300 °C despite decreased phase change enthalpy. The viscosity has a sharp increase from 4.2 cP to 22.4 cP when NPs concentration rises from 0 wt% to 10 wt% at 360 °C. When being applied in TES system, the optimal concentration of MgO NPs is found to be 4 wt%. The thermal charging rate of TES system is suppressed when NPs concentration is too low or too high due to limited thermal conduction and inhibited natural convection, respectively. Viscosity is verified as important as thermal conductivity in system level evaluation. This work helps to guide the design of high-performance molten salts in TES system, so as to achieve both faster thermal charging rate and higher energy storage density.

On the linearized system of equations for the condensate–normal fluid interaction at very low temperature

AbstractThe linearization around one of its equilibrium of a system that describes the correlations between the superfluid component and the normal fluid part of a condensed Bose gas in the approximation of very low temperature and small condensate density is studied. A simple and transparent argument gives a necessary and sufficient condition for the existence of global solutions satisfying the conservation of the total number of particles and energy. The global solutions describe the evolution in time of the density of the thermal cloud and, unlike in previous work, that of the condensate's density. Their convergence to a suitable stationary state is also shown and rates of convergence for the normal fluid and superfluid components are obtained.

Clarifying the Relationship between the Lithium Deposition Coverage and Microstructure in Lithium Metal Batteries.

Improving the reversibility of lithium metal batteries is one of the challenges in current battery research. This requires better fundamental understanding of the evolution of the lithium deposition morphology, which is very complex due to the various parameters involved in different systems. Here, we clarify the fundamental origins of lithium deposition coverage in achieving highly reversible and compact lithium deposits, providing a comprehensive picture in the relationship between the lithium microstructure and solid electrolyte interphase (SEI) for lithium metal batteries. Systematic variation of the salt concentration offers a framework that brings forward the different aspects that play a role in cycling reversibility. Higher nucleation densities are formed in lower concentration electrolytes, which have the advantage of higher lithium deposition coverage; however, it goes along with the formation of an organic-rich instable SEI which is unfavorable for the reversibility during (dis)charging. On the other hand, the growth of large deposits benefiting from the formation of an inorganic-rich stable SEI is observed in higher concentration electrolytes, but the initial small nucleation density prevents full coverage of the current collector, thus compromising the plated lithium metal density. Taking advantages of the paradox, a nanostructured substrate is rationally applied, which increases the nucleation density realizing a higher deposition coverage and thus more compact plating at intermediate concentration (∼1.0 M) electrolytes, leading to extended reversible cycling of batteries.

Design of the Smallest Intramolecular Singlet Fission Chromophore with the Fastest Singlet Fission.

We designed an intramolecular singlet fission (iSF) chromophore, pyrazino[2,3-g]quinoxaline-1,4,6,9-tetraoxide. Appropriate substitutions into anthracene enhance the tetraradical character, so that the molecule accommodates a pair of triplet excitons in its lowest singlet excited state. Our simulation showed a 16 fs fast iSF of the design, which is a new record. The design also sets a new record of small size iSF chromophore and high exciton density. The design can be synthesized by oxidizing the tertiary N centers of the existent pyrazino[2,3-g]quinoxaline.

The infrared features and full rotational constant catalogue of the newly detected MgC2 astromolecule

ABSTRACT The recent radioastronomical detection of magnesium dicarbide (MgC2) towards the carbon-rich star IRC+10216 leads to questions about whether this molecule can be observed in other wavelengths, especially with the wealth of IR data being produced by JWST. This present, theoretical spectral characterization, unfortunately, implies that mid-IR observations of MgC2 are unlikely due to small IR transition intensities, overlap with polycyclic aromatic hydrocarbon IR features, low frequencies/long wavelengths, or the relatively small column densities. In spite of this, the full set of fundamental anharmonic vibrational frequencies are provided for each of the 24Mg, 25Mg, and 26Mg isotopologues as are the complete rotational constants for the same set for additional laboratory characterization. Most notably and with regards to 24MgC2, the B0 and C0 (11452.7 and 9362.7 MHz) rotational constants are uniquely provided for the first time. The experimentally derived A0, (B + C)/2, and (B − C)/4 values are within 0.7 % of the presently computed anharmonic results implying similar accuracy for the remaining spectroscopic constants.

Atomistic Investigation of Titanium Carbide Ti8C5 under Impact Loading

Titanium carbides attract attention from both academic and industry fields because of their intriguing mechanical properties and proven potential as appealing candidates in the variety of fields such as nanomechanics, nanoelectronics, energy storage and oil/water separation devices. A recent study revealed that the presence of Ti8C5 not only improves the impact strength of composites as coatings, but also possesses significant strengthening performance as an interlayer material in composites by forming strong bonding between different matrices, which sheds light on the design of impact protection composite materials. To further investigate the impact resistance and strengthening mechanism of Ti8C5, a pilot Molecular Dynamics (MD) study utilizing comb3 potential is carried out on a Ti8C5 nanosheet by subjecting it to hypervelocity impacts. The deformation behaviour of Ti8C5 and the related impact resist mechanisms are assessed in this research. At a low impact velocity ~0.5 km/s, the main resonance frequency of Ti8C5 is 11.9 GHz and its low Q factor (111.9) indicates a decent energy damping capability, which would eliminate the received energy in an interfacial reflection process and weaken the shock waves for Ti8C5 strengthened composites. As the impact velocity increases above the threshold of 1.8 km/s, Ti8C5 demonstrates brittle behaviour, which is signified by its insignificant out-of-plane deformation prior to crack initiation. When tracking atomic Von Mises stress distribution, the elastic wave propagation velocity of Ti8C5 is calculated to be 5.34 and 5.90 km/s for X and Y directions, respectively. These figures are inferior compared with graphene and copper, which indicate slower energy delocalization rates and thus less energy dissipation via deformation is expected prior to bond break. However, because of its relatively small mass density comparing with copper, Ti8C5 presents superior specific penetration. This study provides a fundamental understanding of the deformation and penetration mechanisms of titanium carbide nanosheets under impact, which is crucial in order to facilitate emerging impact protection applications for titanium carbide-related composites.

Sound Propagation in Cigar-Shaped Bose Liquids in the Thomas-Fermi Approximation: A Comparative Study between Gross-Pitaevskii and Logarithmic Models

A comparative study is conducted of the propagation of sound pulses in elongated Bose liquids and Bose-Einstein condensates in Gross-Pitaevskii and logarithmic models, by means of the Thomas-Fermi approximation. It is demonstrated that in the linear regime the propagation of small density fluctuations is essentially one-dimensional in both models, in the direction perpendicular to the cross section of a liquid’s lump. Under these approximations, it is demonstrated that the speed of sound scales as a square root of particle density in the case of the Gross-Pitaevskii liquid/condensate, but it is constant in a case of the homogeneous logarithmic liquid.

The role of propagule pressure in experimental bark beetle invasions

Abstract Although many non‐native species arrive in novel environments, only a fraction successfully establish. A crucial factor affecting the colonization process of invading species is propagule pressure. The positive association between propagule pressure and colonization probability is driven both by stochastic dynamics and the ‘Allee effect’. Although the role of Allee effects in invading populations is theoretically compelling, they are difficult to quantify in the field because the earliest phases of biological invasions are typically not observed. We conducted parallel studies using two species of bark beetles, Hylurgus ligniperda in New Zealand and Ips pini in North America, to (i) assess the role of propagule pressure on colonization success, (ii) empirically test for Allee effects and (iii) estimate Allee thresholds. We evaluated each of these factors by experimentally testing the effect of propagule pressure (numbers released) on simulated tree colonization success in two different settings: (1) field conditions where beetles could disperse freely and (2) enclosed cages where dispersal loss was prevented. Colonization success was positively associated with numbers released (i.e. propagule pressure) for both species, though colonization occurred at lower numbers for H. ligniperda than for I. pini. A demographic Allee effect was only detected in H. ligniperda and the Allee threshold was smaller when beetles were released 1 m from host billets than when they were released 10 m away. Greater colonization success at lower release densities may explain the invasion success of H. ligniperda worldwide. Higher release densities required for successful colonization may explain why I. pini is a poor establisher. Synthesis and applications. Our results linking invasion failure to small founding population densities generally support the theoretical literature on the role of propagule pressure and Allee effects in biological invasions. Agencies such as the International Plant Protection Committee (IPPC) setting phytosanitary measures such as the International Standards for Phytosanitary Measures No. 15 (ISPM 15) should consider using the colonization thresholds estimated here to limit numbers of colonizing individuals below invasion thresholds. Additionally, agencies conducting trapping efforts at ports‐of‐entry should be aware of these thresholds and widely report when trapping numbers exceed these thresholds.

A Multifunctional Flexible Electronic Skin for Dynamic Thermal Radiation Regulation and Electromagnetic Interference Shielding.

A multifunctional electronic skin with thermal radiation regulation and electromagnetic interference (EMI) shielding is urgent for electronic systems because of the thermal radiation emission and electromagnetic wave pollution. Herein, a flexible electronic skin was designed and fabricated, where the polyaniline (PANI) served as the functional layer and Ti3C2Tx MXene was employed as the conductive electrode. The transformation of emeraldine salt (ES) and leucoemeraldine base (LB) of PANI makes the skin achieve an infrared emissivity modulation, and the electromagnetic loss of PANI and ultrahigh electrical conductivity of Ti3C2Tx MXene make it exhibit EMI shielding ability. Benefiting from the special structural design, the multifunctional skin with a small thickness (0.3 mm) and low surface density (0.06 g/cm2) exhibits an excellent infrared emissivity modulation ability (Δε) of 0.32 with emissive power of 119.1 W/m2 at the wavelength range of 2.5-25 μm and total shielding effectiveness (SET) of 36.3 dB over the X-band (8.2-12.4 GHz). Meanwhile, the multifunctional skin remains black in the visible spectrum but a changeable color in the infrared spectrum. Even after repeated bending and twisting, the multifunctional skin still maintains a good emissivity adjustment. The simultaneous realization of dynamic thermal radiation regulation and EMI shielding endows the skin promising potential for various fields, such as adaptive infrared camouflage, thermal regulation, anticounterfeiting, and EMI shielding-related crossing field.

Anti-blast analysis and design of a sacrificial cladding with graded foam-filled tubes

Foam-filled tubes are excellent energy absorption structures for impact resistance, and graded foam may have superiority for the design of anti-blast sacrificial cladding. The anti-blast response of density-graded foam-filled tubes as a core layer is investigated numerically and theoretically. Mesoscopic finite element models for graded foam-filled tubes are constructed, and their constant-velocity compression and anti-blast performance are simulated. One-dimensional analytical shock models based on an empirical force–displacement relationship are developed to analyze the axial collapse wave propagation in graded foam-filled circular tubes. Single-/double-wave deformation patterns are observed for graded foam-filled tubes under blast loading, especially the negatively graded foam-filled tubes with gradient parameters close to zero may also show a single-wave deformation pattern. The results demonstrate that the negatively graded foam-filled tube with a small density gradient is a good choice to design anti-blast sacrificial cladding with a small critical length and a low transmitted force. A contour map of the critical length required to absorb the impulse of blast loading for different gradient parameters and diameter-thickness ratios of the outer tube is established. This study proposes a new design guideline for superior blast resistance structures in engineering applications.

Role of micellar entanglements on kinetics of shear banding flow formation

We investigate the effects of micellar entanglement number on the kinetics of shear banding flow formation in a Taylor–Couette flow. Three sets of wormlike micellar solutions, each set with a similar fluid elasticity and zero-shear-rate viscosity, but with varying entanglement densities, are studied under the startup of steady shear. Our experiments indicate that in the set with low fluid elasticity, the transient shear banding flow is characterized by the formation of a transient flow reversal in a range of entanglement densities. Outside of this range, the transient flow reversal is not observed. For the sets of medium and high elasticities, the transient flow reversals exist for relatively small entanglement densities and disappear for large entanglement densities. Our analysis shows that wall slip and elastic instabilities do not affect the transient flow feature. We identify a correlation between micellar entanglement number, the width of the stress plateau, and the extent of the transient flow reversal. As the micellar entanglement number increases, the width of the stress plateau first increases; then, at a higher micellar entanglement number, the plateau width decreases. Therefore, we hypothesize that the transient flow reversal is connected to the micellar entanglement number through the width of the stress plateau.

Modification and durability of carbon paper gas diffusion layer in proton exchange membrane fuel cell

To solve the durability problem caused by carbon corrosion in the porous carbon paper gas diffusion layer (GDL) of proton exchange membrane fuel cell (PEMFC), a Cr7C3 ceramic coating on porous carbon paper by molten salt method was prepared. The obtained Cr7C3 coating is dense and shows good adherent with the carbon paper. Based on the corrosion resistance testes, it is concluded that the Cr7C3 coated carbon paper can keep high chemical stability in the long-time acid immersion accelerated corrosion tests and simulated cathodic proton exchange membrane fuel cells environment. The carbon paper with Cr7C3 coating shows a small current density with a value of about 1.1 × 10−5 A cm−2 in the potentiostatic polarization test under 1 M H2SO4 + 2 ppm HF at 70 °C and1.4 VSCE for 72 h. Meanwhile, the resistivity of carbon paper with Cr7C3 coating prepared is 30% lower than that of pure carbon paper, and the conductivity is 1.5 times that of pure carbon paper.