Table of Content

28 February 2026, Volume 32 Issue 1

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Special Paper

Reproducibility of high-throughput density functional theory calculations

LU Chenxi, LI Musen, Jefirey Robert REIMERS

2026, 32(1):  1-16.  doi:10.12066/j.issn.1007-2861.2693

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While standard computational protocols for density functional theory (DFT) have universal applicability, differences exist in code implementations. Specific applications require manual parameter optimization, whereas high-throughput calculations employ predefined workflows. This paper uses the bandgap as a key property to reveal the impact of computational workflow differences on the reproducibility of high-throughput calculation results. The study proposes basic requirements for ensuring reproducibility: using structures optimised using the same procedure as used to calculate properties and ensuring Brillouin zone integration grid accuracy. This research establishes a foundation for the reproducibility of DFT calculations and reliable application of results, which is of great significance for method development and artificial intelligence model training.

Materials Science

Rare earth nickelates: metal-insulator transition and superconducting properties

LI Minjuan, CHEN Mingyao, YIN Xinmao, CAI Chuanbing

2026, 32(1):  17-32.  doi:10.12066/j.issn.1007-2861.2577

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A comprehensive introduction was provided to the basic structure and properties of rare earth nickelates, offering an in-depth summary of their metal-insulator transition (MIT) characteristics as well as the regulation of the MIT process by epitaxial strain, film thickness, and chemical doping. In addition, research on hydrogen-induced phase transition in nickelates was discussed, and a systematic reference was provided to understand and regulate the MIT. Furthermore, the superconductivity of nickelates was reviewed, and it included the exploration of superconductivity in this system and the research progress on La₃Ni₂O₇ superconductors. The summarized research on nickel-based superconductors not only contributed to the acceleration of the exploration of novel superconducting materials but also held significant research value in its uncovering of the mechanisms of high-temperature superconductivity.

Temperature-dependent band gap of thermoelectric PbTe from first-principles calculations

GAN Lu, YANG Jiong, XI Jinyang

2026, 32(1):  33-43.  doi:10.12066/j.issn.1007-2861.2700

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The band gap is one of the most fundamental properties of semiconductors. Manystudies have demonstrated that temperature-induced vibrations have a significant impact on the band gap. In this paper, the band structure of the thermoelectric compound PbTe at finite temperature is investigated using first-principles calculations, focusing on the effects of electron-phonon renormalization (EPR) and spin-orbit coupling (SOC) on the temperature-dependentband gap. The results reveal that EPR leads to temperature- dependent variations in the band gap of PbTe, while the inclusion of SOC reverses the trend of band gap change (without SOC, the band gap decreases by 88 meV as the temperature rises from 0 K to 750 K, while the band gap increases by 144 meV with SOC). Furthermore, the zero-point renormalization contributes minimally to the band gap change. Therefore, both EPR and SOC effects have a significant influence on the band gap of PbTe and must be taken into account. This paper provides theoretical insight into the temperature dependence of PbTe’s band gap and ofiers guidance for optimizing its thermoelectric performance.

Polarity control of two-dimensional semiconductor MoTe₂ and its applications in reconfigurable electronics

HE Xiaoqian, GOU Xiaoshuang, SUN Fuqin, ZHAO Zhanxia, WANG Xiaowei, ZHANG Ting

2026, 32(1):  44-53.  doi:10.12066/j.issn.1007-2861.2706

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To explore the carrier polarity modulation of two-dimensional semiconductor molybdenum ditelluride (MoTe₂) and its applications in reconfigurable electronic devices, a dual-gate field-effect transistor (FET) based on a tantalum oxide (TaO_x)/MoTe₂/hexagonal boron nitride (h-BN) heterostructure was constructed. The reversible polarity control of MoTe₂ is achieved via charge trapping/detrapping effects at the TaO_x/MoTe₂ interface under the gate electric field. The results demonstrate that the carrier polarity in MoTe₂ can be modulated reversibly by controlling pulse polarity and amplitude of control gate (CG). A negative pulse voltage weakens the p-type characteristics and promotes the ntype characteristics of MoTe₂. Conversely, a positive pulse voltage enhances the p-type while suppressing the n-type behavior. Notably, this modulation effect becomes more pronounced with increasing voltage amplitudes. Based on this method, a logic inverter was successfully fabricated via programming two series-connected MoTe₂ transistors into n-type and p-type, respectively. This strategy of polarity modulation in two-dimensional semiconductors through interface charge trapping effects is considered to provide a novel idea for developing functionally reconfigurable electronic devices.

Mechanics and Civil Engineering

Enhanced imbibition effect of nanofluids and driving characteristics of oil drainage in fractured ultra-low permeability reservoirs

XUE Peiyu, GU Chunyuan, LI Yuhua, ZHU Junjie

2026, 32(1):  54-66.  doi:10.12066/j.issn.1007-2861.2617

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A series of in situ imbibition imaging experiments were carried out by using the self-developed nanofluid SNF-SL to study the imbibition effects and oil drainage imaging characteristics of nanofluids in ultra-low permeability core. Based on the influence of nanofluids on factors such as core wettability, oil-water interfacial tension, and viscosity, the synergistic effects of nanofluids on the power and resistance of imbibition were analyzed, and the mechanical mechanism of nano-enhanced imbibition was expounded. The results showed that the imbibition recovery rate of nanofluids in fractured cores with ultra-low permeability was 2.63% and 5.75% higher than that of nanofluids in hydrophilic cores. Nanofluid with concentration ranging from 0.15% and 0.3% could reduce the oil-water interfacial tension by 59% and 65% and the contact angle of the core surface from 73.8- to 9.5- and 6.6-, and the reduction rate of viscosity could reach 39% and 48%. Therefore, the capillary force of imbibition was increased by 24% and 44.6%. The adhesion work of crude oil was reduced by 99.2% and 99.7%. The internal friction resistance was reduced by 39% and 48%. The results demonstrated that the vertical fractures had the best imbibition effect, followed by the horizontal fractures, which were higher than the recovery rate of the matrix core. The reason lay in the fact that the fractures increased the action area between the nanofluid and the core and shortened the oil drainage distance of transverse imbibition, and the oil drainage speed was accelerated by the vertical fractures based on gravity differentiation. The higher concentration or temperature of the nanofluid led to a higher oil drainage efficiency of imbibition. The synergistic effects of improving the power of imbibition and reducing the internal and external friction resistance occured through the dual action of the nanofluid on the core and crude oil, improving the oil drainage effects of imbibition, which reflected the mechanical mechanism of the nanofluid to enhance imbibition.

Large eddy simulation of aerodynamic and aeroacoustic performances of tandem blades

WEN Chuyi, TANG Xiaolong, DING Jue, YANG Xiaoquan, WENG Peifen

2026, 32(1):  67-82.  doi:10.12066/j.issn.1007-2861.2696

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To explore the aerodynamic and aeroacoustic performance of a newly designed tandem blade configuration, numerical simulations were conducted using large eddy simulation (LES) combined with the Ffowcs-Williams and Hawkings (FW-H) integral. The performance responsed to the change of blade spacing was also discussed. The results showed that under subsonic and moderate Reynolds number conditions (Ma = 0.21, Re = 7×10⁵), the noise generated by tandem blades mainly originated from the aft blade and it carried a broadband characteristic. Influenced by the downwash and upwash flows from the blade tip and root, the noise generated by tandem blades tended to be concentrated near the blade mid-span. As the blade spacing increased, the wake behind the fore blade became stronger as a result of enhanced energy accumulation, and the time delayed between the upstream and downstream blades became longer. This led to an increase in the total sound pressure level (SPL) and a shift of the acoustic energy toward lower frequencies.

Characteristics of counter-gradient heat transport structures in homogeneous shear turbulence under stable stratification

LI De, LU Zhiming

2026, 32(1):  83-95.  doi:10.12066/j.issn.1007-2861.2611

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By using the direct numerical simulation method, the characteristics of counter-gradient heat transport in homogeneous shear turbulence under stable thermal stratification were investigated. The cluster connectivity method was employed to thoroughly examine the statistical properties of counter-gradient heat transport structures, including their geometric features and spatial distribution. The Reynolds number was set at Re_x=5 000, and the Richardson numbers Ri were set to 0, 0.1, and 0.2, respectively. The simulation results reveal significant impacts of stable thermal stratification on turbulence structures. The number of counter-gradient transport regions significantly increases by introducing thermal stratification, and the relevant structures are elongated in the streamwise direction. Furthermore, the inclination angle between the structures and the streamwise direction is reduced by stable stratification. In the vertical direction, "ejection" and "sweep" heat fluxes exhibit a characteristic of paired distribution along the diagonal direction, and with increasing stratification intensity, "sweep" structures tend to appear below "ejection" structures. The flndings of this study deepen the understanding of counter-gradient heat transport in stratified shear turbulence and are useful for further exploration of the physical mechanisms underlying the counter-gradient transport phenomenon.

Effect of thermal radiation and particle size dispersity on flow and heat transfer in particle-laden turbulent channel flow

WANG Xuerou, FAN Dongliang, TANG Xiaofeng, DONG Yuhong

2026, 32(1):  96-107.  doi:10.12066/j.issn.1007-2861.2619

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Particle-laden turbulent channel flow is prevalently manifested in natural and engineering applications, so the investigation of its flow and heat transfer characteristics holds significant importance. In this paper, the effect of the particle size dispersity of radiatively heated particles on particle distribution morphology and its modulation effect on the flow in vertical turbulent channel flow were investigated. Direct numerical simulation was used for fluid phase, and Lagrange-point tracking model was used for particle phase. The momentum and heat exchange between particles and fluid were considered. The research results reveal that the multi-scale turbulent structure exerts distinct centrifugal effects on particles with different particle sizes in the flow field, leading to the accumulation of polydisperse particles at disparate positions and resulting in a more homogeneous distribution of polydisperse particles in the flow field compared to that of monodisperse particles. Moreover, the spatial position distribution of the particles influences the interphase energy exchange, such that compared to the heated monodisperse particle-laden turbulent channel flow, the heated polydisperse particles accelerate the interphase momentum and heat exchange, enhance the momentum and temperature of the fluid, and concurrently avoid the temperature extremum in the flow field.

Three-dimensional structure and dynamics of flame rings in narrow channels

FAN Miao, LU Zhanbin

2026, 32(1):  108-115.  doi:10.12066/j.issn.1007-2861.2620

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Flame rings can be considered as premixed flame units with a topology structure similar to flame balls within confined spaces. Numerical methods were employed to investigate the axisymmetric two-dimensional steady-state solutions of flame rings in narrow channels and their response to changes in channel height. The stability of flame rings under radial and three-dimensional small perturbations was examined. Comparative analysis was conducted on the results obtained by using linear approximation assumptions along the channel height direction, and the qualitative reasonableness and effectiveness of the linear approximation assumptions were validated. Meanwhile, from a quantitative perspective, this study reveals the true three-dimensional structure of flame rings and their stability under three-dimensional perturbations, laying a solid foundation for researching and understanding the more complex three-dimensional dynamics of flame rings in the future.

Pull-out test of strengthening rib geogrid based on FBG and 3D printing

CHEN Zhifu, ZHANG Mengxi, DAI Zhiheng, CHEN Changmao

2026, 32(1):  116-129.  doi:10.12066/j.issn.1007-2861.2654

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Based on 3D printing and fiber Bragg grating (FBG), a strengthening rib geogrid with FBG pressure sensing zones is prepared, and its reliability in soil is verified through experiments. Pull-out tests are conducted to study the pull-out interface characteristics of strengthening rib geogrids under different rib heights, spacings, and numbers, as well as the variation patterns of lateral pressure on the strengthening ribs. Based on the punching shear failure mechanism, the theoretical calculation formula for the passive lateral pressure of the strengthening ribs is established. The results show that strengthening ribs can effectively improve the pull-out resistance of geogrids. The ultimate pull-out force of the geogrid increases with the rib height and the number of ribs, while an excessively small rib spacing reduces the ultimate pull-out force. The passive lateral pressure of the ribs increases gradually with the pull-out displacement and stabilizes after reaching the peak value. The active lateral pressure decreases first and then stabilizes. The passive lateral pressure of the strengthening ribs located on the longitudinal ribs is slightly smaller than that on the mesh. In the case of multiple strengthening ribs, the passive lateral pressure of the strengthening ribs on the rear side in the pull-out direction decreases, and the smaller the rib spacing, the greater the degree of reduction. The theoretical calculation results of the passive lateral pressure of the strengthening ribs are in basic agreement with the experimental results. These results verify the feasibility of embedding FBG sensors into the strengthening ribs of geogrids to monitor lateral pressure and deepen the theoretical understanding of the interaction mechanism between strengthening rib geogrids and backfill.

BIM-based multi-objective optimization of foundation pit strut structural design using NSGA-Ⅱ algorithm with enhanced constraints

HU Ruofan, SHU Zhan

2026, 32(1):  130-141.  doi:10.12066/j.issn.1007-2861.2702

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With increasing emphasis on environmental sustainability in the construction industry, carbon emissions in the design of large-scale foundation pit strut systems has become a critical issue that must be taken into account. While traditional designs prioritize cost-effectiveness, they often lack consideration of environmental performance. This paper proposes a building information modeling (BIM)-based enhanced constraint method and integrates it into the NSGA-Ⅱ framework to achieve multi-objective optimization of foundation pit strut design. First, carbon emission calculation criteria for foundation pit support systems are established, and the boundary conditions are defined, covering life-cycle stages including material production, transportation, construction, demolition, and recycling. On this basis, an enhanced constraint method is proposed to transform design codes into quantitative constraint conditions and combine them with the NSGA-Ⅱ algorithm. Structural information is extracted through a BIM platform to improve the accuracy and practicality of the optimization process. Finally, two typical foundation pit support cases are analyzed to verify the effectiveness and applicability of the proposed method. Compared with traditional designs, the optimization algorithm demonstrates significant improvements in both cost efficiency and carbon emission reduction. Specifically, cost optimization efficiency and carbon performance improve by 40.9% and 30.1%, and by 25.3% and 20.9%, respectively, in the two cases. This approach provides a more scientific and effective optimization methodology for foundation pit strut structural design.

Indoor model test on erosion coating of damaged buried water supply pipe

LU Xiuying, LU Ye

2026, 32(1):  142-152.  doi:10.12066/j.issn.1007-2861.2543

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An indoor model test was conducted to study the erosion failure pattern, erosion height, and erosion velocity of the soil layer, considering three influencing factors: soil type, water inflow pressure, and water supply pipe diameter. The results showed that the soil type affected the form of erosion failure. Collapse cavities accumulated on top of the erosion zone in a sand layer, while the erosion zone in a clay layer maintained a temporary stability. Moreover, the gravelly sand layer exhibited a rearrangement of the soil particles into a "fine upper and coarse lower" layer. Increasing the water inflow pressure, and reducing the water supply pipe diameter substantially increased the erosion pressure on the damaged mouth. The overburdened surface transformed from a downward collapse failure to an upward hill failure. Based on the test similarity scale and erosion height curve, the erosion time for a damaged jet in a similar engineering environment could be estimated, providing a reference for the construction and maintenance of urban underground water-supply networks.

Performance test of controlled low strength material prepared by engineering waste soil combined with construction waste sand

CHEN Ying, LI Dong, GENG Jian, WANG Zhirong, YOU Xinyu, SHI Lei, FANG Ming

2026, 32(1):  153-165.  doi:10.12066/j.issn.1007-2861.2511

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A solid waste controlled low strength material (CLSM) was prepared using engineering waste soil and construction waste sand as fine aggregates. The fluidity, bleeding rate, and unconfined compressive strength of the CLSM were studied by considering the substitution rate of the engineering waste soil, particle/powder ratio of the engineering waste soil, water-solid ratio, and binder-aggregate ratio as influencing factors. The hydration and hardening characteristics of the CLSM were investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the fluidity of the CLSM decreases with an increase in the engineering waste soil content; however, it can effectively control bleeding, and it promotes early strength but weakens later strength. The smaller the particle/powder ratio, the more water is needed for the CLSM to reach the same fluidity, which has little effect on the 28 d strength. Under the influence of the watersolid ratio, the fluidity and 28 d strength of the CLSM are negatively correlated, whereas the two indexes are positively correlated under the influence of the binder-aggregate ratio. The results of microscopic analyses show that the formation of CLSM hydration products was mainly owing to the hydration reaction of cement and slag powder, whereas the ion exchange and granulation of engineering waste soil had limited influence on the hydration system. In this experimental system, the solid-waste CLSM slurry not only has excellent working performance with a high fluidity (>200 mm) and low bleeding ratio but also can satisfy backfill engineering applications requiring secondary excavation (<2.1 MPa), which provides a new idea for the resource utilization of low-quality building solid waste.

Mathematics

The non-uniform L1-2 formula for Caputo derivatives and its applications

WANG Junling, LI Dongxia

2026, 32(1):  166-186.  doi:10.12066/j.issn.1007-2861.2658

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This paper constructs a numerical approximation formula for the Caputo derivative of order α∈(0，1). Considering the weak regularity of the Caputo derivative at the initial time, linear interpolation is employed over the first subinterval of the non-uniform mesh, while quadratic interpolation is utilized for each subsequent subinterval, leading to the derivation of a non-uniform L1-2 formula. It is proven that the truncation error can achieve (3-fi)-order accuracy, and the corresponding coefficient properties are discussed. The derived formula is applied to the numerical solution of the time-fractional diffusion equation, and numerical experiments have verified the effectiveness and correctness of the formula.