Changes In Conductivity Research Articles

Active control of thermal conductivity of low-dimensional α -PbS by strain-induced ferroelectric

Active control of heat transfer in nanostructured materials is crucial for the development of microelectronic devices. Thermal switch is a typical heat management device, which has attracted widespread attention. In this work, based on first-principles calculations, we propose a two-dimensional thermal switch based on the strain-induced ferroelectric phase transition in α-PbS. It is found that thermal conductivity can be significantly reduced by external strain and a room temperature two-dimensional thermal switch with a switch ratio of 3.7 can be constructed. The calculated phonon lifetime and scattering rate reveal that phonons around 2 THz frequency range predominantly contribute to the modulation in thermal conductivity when the strain is smaller than 2.0%. A detailed analysis on phonon dispersion indicates that these phonons are LO2 and TO3 branches. When the strain is larger than 2.0%, the decrease in phonon group velocity leads to the reduction in thermal conductivity. Our work elucidates the mechanisms for changes in the thermal conductivity of α-PbS under strain and provides a low-dimensional thermal switch, which is promising for future applications in microelectronic devices.

Ti3C2Tx MXene/Graphene hybrid frameworks for constructing thermally conductive phase change composites with solar-thermal conversion ability

Application of three-dimensional (3D) carbon framework in phase change material (PCM) has aroused a tremendous interest. However, implementing a high alignment carbon framework with low interfacial thermal resistance (ITR) remain challenging. Herein, we demonstrated a synergetic effect strategy by Ti3C2Tx MXene and graphene nanoplate (GNP) to achieve a 3D thermally conductive framework with high alignment skeleton and low filler-to-filler ITR. Typically, the 3D anisotropic carbon framework is fabricated by unidirectional ice template freezing cellulose nanofibers (CNF)/GNP solution with the assistance of MXene. The abundant functional groups of MXene and the similar layered structure promote the dispersion stability of GNP in CNF aqueous solution, resulting in the significant improvement in GNP alignment and the filler-to-filler ITR. Therefore, the final phase change composites obtained by impregnating polyethylene glycol (PEG) into the framework achieves a satisfactory thermal conductivity (TC) of up to 3.49 W/m K at only 6.25 vol% filler loading. Combining the solar-thermal conversion ability of graphene and MXene, the PCM reveals a rapid energy conversion, transfer and storage capability. More importantly, the phase change enthalpy of the PCM can be as high as 164.3 J/g, with little change even after 50 heating-cooling cycles, and the existence of carbon framework can effectively prevent the leakage phenomenon in solid-liquid conversion process, ensuring its shape stability.

Evaluating the Effects of Proppant Flowback on Fracture Conductivity in Tight Reservoirs: A Combined Analytical Modeling and Simulation Study

This work establishes an analytical model for determining the critical velocity for proppant flowback, and evaluates how proppant flowback affects fracture conductivity for tight reservoirs. The multiphase effects are considered for determining the critical velocity for proppant flowback before and after fracture closure, respectively. The model’s performance is demonstrated by comparing the results against previous models. A finite-element model is built to simulate the proppant flowback process for a hydraulic-fractured well completed in the Ordos Basin. The change in fracture conductivity caused by proppant flowback for several scenarios with varying saturation and net pressure in fractures is further quantitatively assessed. Our results highlight the importance of multiphase effects in determining the critical velocity for proppant flowback at relatively low water saturation in fractures. The critical velocity generally increases with increasing water saturation in fractures and net pressure in fractures. At a flowback velocity higher than the critical value, the loss in fracture conductivity becomes relatively more pronounced at a lower water saturation in fractures and a lower net pressure in fractures. The findings of this work are expected to provide insights into the mechanisms of proppant flowback and flowback drawdown management for field operations in tight reservoirs.

EFFECT OF SILVER DOPING ON IRON OXIDE ELECTRICAL PROPERTIES

Iron silver oxide (Agx[Formula: see text]O3; [Formula: see text]) structure for photoelectrochemical (PEC) water splitting was grown by RF–DC co-sputtering of an iron–silver target in argon/oxygen plasma mixtures at 300°C, followed by thermal annealing at 560°C. The chemical composition and structure of the deposited film can be tuned by controlling the metal doping and the annealing temperature. The thermal treatment extensively improves the PEC water-splitting performances of the films. XRD patterns of AgxFe[Formula: see text]O3 shown in the figure can be indexed to the hexagonal structure of silver oxide and the rhombohedral structure of hematite and new X-ray Diffraction (XRD) peaks of AgxFe[Formula: see text]O3 structure. The annealing and doping process seems to cause a serious change in the crystal structure of the thin film, it showed a serious change in its electrical properties. The electrical parameters of resistance for thin films were measured using the Hall measurement method at room temperature. With Hall measurements, the n-type carrier concentration of the Fe2O3 structure was calculated, and it was observed that its resistance was 1[Formula: see text]M[Formula: see text]. Likewise, it was observed that AgxFe[Formula: see text]O3 exhibited an n-type carrier concentration, and its resistance was calculated to be 0.5[Formula: see text]M[Formula: see text]. The conductivity change is based on silver doping. The doping process seems to cause a change in the bandgap of the thin film, it showed a change in its optical properties. The film’s optical absorption was measured by UV–Vis photo spectroscopy. Subsequently, the structural and topographic properties of AgxFe[Formula: see text]O3 structures were investigated by high-precision characterization devices.

Alterations in Physiological Parameters and Secondary Metabolites of Astragalus adsurgens Infected by the Pathogen Alternaria gansuensis

Alternaria gansuensis, a seed-borne fungus of standing milkvetch (Astragalus adsurgens), is the most common pathogen of this plant species and causes yellow stunt and root rot. Although plant resistance to this disease has been identified, a better understanding of the nature of this resistance will help improve and optimize its implementation in standing milkvetch. The effects of A. gansuensis on the physiology of standing milkvetch were assessed in a 4-week study comparing a resistant plant variety, Shanxi, and a susceptible variety, Ningxia. In the first week, there was an obvious decrease in photosynthesis (P) in inoculated plants, especially in the susceptible variety, but there were no changes in stomatal conductance (Sc). From the second week on, P and Sc decreased progressively, and significant stem lesions were observed concomitantly. Water use efficiency (WUE) increased slightly in the second week but then decreased significantly from the third week. Physiological changes observed for the resistant variety of standing milkvetch were less dramatic than those of the susceptible variety. Hyphae were observed around inoculation lesions of the plants. Culture filtrate (CF) of A. gansuensis induced changes in extracellular pH and conductivity, especially in the susceptible variety samples. Tissue integrity changes in the plants correlated with the decrease in P. Secondary metabolite compounds were extracted from the plants and 21 types of compounds were identified. The composition and proportion of secondary metabolites were markedly altered by the pathogen, and these differences may indicate potential mechanisms of disease resistance to A. gansuensis in standing milkvetch.

Adsorption and sensing properties of TiO2-modified MoSe2 monolayer for SF6 decomposition components based on the first-principles

As crucial components in power systems, SF6 gas-insulated equipment inevitably develops insulation defects and faults over long-term operation, leading to the decomposition of SF6 gas. Therefore, detecting SF6 decomposition components is essential for assessing the operational status of SF6 gas-insulated equipment and ensuring the safe and stable operation of power systems. Based on first principles, the modification mechanism of TiO2 on MoSe2 was explored, and optimal adsorption models for gases SO2, H2S, SOF2, and SO2F2 on this composite material were established. The adsorption characteristics of each system were analyzed through parameters such as adsorption energy, adsorption distance, charge transfer, electron density difference, and density of states, and the sensing properties of the systems were discussed using parameters including changes in frontier molecular orbitals, desorption time, and sensitivity. The results indicate that TiO2–MoSe2 has difficulty capturing SO2F2, but exhibits chemisorption for SO2, H2S, and SOF2 with adsorption energies of −1.25 eV, −0.99 eV, and −3.40 eV, respectively. Upon adsorption of SO2, TiO2–MoSe2 shows a significant change in electrical conductivity, a desorption time of 4.51 s (at 498 K), and a strong sensitivity response. However, the response to H2S is relatively weak, with lower sensitivity. Therefore, this material is suitable for detecting SO2 but not H2S. TiO2–MoSe2 demonstrates a significant response and excellent sensitivity to SOF2; however, the adsorption process lacks repeatability. Therefore, it can be used as a disposable gas sensor or solid adsorbent for SOF2 detection. The results of this study provide theoretical support for the application of MoSe2-based sensors in the monitoring and fault diagnosis of SF6 gas-insulated equipment.

Tunable memory behavior in light stimulated artificial synapse based on ZnO thin film transistors

Abstract Optoelectronic synapses are inevitable for realizing neuromorphic vision systems, which require the integration of image recognition, memory and image processing into a single platform. In this work, we present a three terminal optoelectronic synapse created using zinc oxide (ZnO) thin film transistor. The persistent photoconductivity (PPC) of ZnO thin film is utilized to demonstrate the synaptic behaviour. The change in conductance of the device under UV illumination has been interpreted as the weight change in the synapse. The basic synaptic functions such as sensory memory, short term memory, long term memory, duration time dependent plasticity and paired pulse facilitation have been successfully demonstrated. The device shows a PPF index of 160\%, comparable to other optoelectronic synapses reported in literature. Further, to corroborate the existing theory that PPC is caused by oxygen vacancies, additional characterizations are carried out and the presence of oxygen vacancies is detected in the fabricated ZnO device. Subsequently, pattern recognition of MNIST handwritten dataset has been performed using the conductance tuning curves of the proposed ZnO TFT based synapses in a neural network architecture, thereby demonstrating their feasibility to be used in neuromorphic applications.

Caught between two states: The compromise in acclimation of photosynthesis, transpiration and mesophyll conductance to different amplitudes of fluctuating irradiance.

While dynamic regulation of photosynthesis in fluctuating light is increasingly recognized as an important driver of carbon uptake, acclimation to realistic irradiance fluctuations is still largely unexplored. We subjected Arabidopsis thaliana (L.) wild-type and jac1 mutants to irradiance fluctuations with distinct amplitudes and average irradiance. We examined how irradiance fluctuations affected leaf structure, pigments and physiology. A wider amplitude of fluctuations produced a stronger acclimation response. Large reductions of leaf mass per area under fluctuating irradiance framed our interpretation of changes in photosynthetic capacity and mesophyll conductance as measured by three separate methods, in that photosynthetic investment increased markedly on a mass basis, but only a little on an area basis. Moreover, thermal imagery showed that leaf transpiration was four times higher under fluctuating irradiance. Leaves growing under fluctuating irradiance, although thinner, maintained their photosynthetic capacity, as measured through light- and CO2-response curves; suggesting their photosynthesis may be more cost-efficient than those under steady light, but overall may incur increased maintenance costs. This is especially relevant for plant performance globally because naturally fluctuating irradiance creates conflicting acclimation cues for photosynthesis and transpiration that may hinder progress towards ensuring food security under climate-related extremes of water stress.

Anisotropic and shape-stable sugarcane-based phase change composites in the application of solar thermal energy storage

The study of anisotropically thermal conductive phase change composites (PCCs) with shape-stability is of great importance to improve the intermittent issues in solar thermal utilization, while some drawbacks like the high cost, low thermal conductivity, and poor durability of current PCCs restrains their practical applications. Herein, a cheap and scalable biomass-based PCC containing carbonized sugarcane (CSC), polyethylene glycol (PEG), and graphene (GF) is proposed. The abundant vessels inside CSC result in a high PEG loading rate of 82.48 %. The naturally occurring anisotropic structure inside CSC can drive GF to be oriented along the lengthwise direction, which gives PCC a high thermal conductivity anisotropy degree of 1.45. The prominent anisotropy improves the lengthwise thermal diffusion and restrains the transverse heat leakage to the environment. Besides, the loaded GF can further enhance the light absorption of PCC to 98 %. As a result, the prepared PCC can achieve high solar-thermal energy storage efficiencies of 79.3–91.7 % with variable solar intensity from 1 to 2 suns. Meanwhile, good anti-leakage and durability performances promote the practical utilization of PCCs. The present work paves a promising road for manufacturing biomass-based anisotropic PCCs in efficient solar thermal energy storage.

Do gravel highways affect water quality and invertebrate communities in Arctic lakes?

ABSTRACT Gravel roads are a common feature in developed areas of Canada’s Arctic. These roads can be a source of calcareous dust that drifts to roadside lakes, causing significant changes in conductivity, calcium, and pH levels. In this study, we examined if road proximity was associated with differences in water quality and invertebrate communities in lakes along the Dempster and Inuvik-Tuktoyaktuk Highways in the Northwest Territories, Canada. We collected biological and water quality data from 18 lakes selected using a stratified random sampling design, with distance from the road (0–300 m, 300–600 m, and >600 m) and region of study (boreal forest, tundra) as the two factors. We hypothesized that lakes closer to the road would exhibit differences in water quality and invertebrate communities associated with road dust pollution and other stressors caused by roads. We found no clear differences in water quality or invertebrate communities among lakes based on distance from the highways. In addition, while there were differences between regions, these did not appear to be related to the effects of the roadways. Our results suggest that variability in lake morphometry and water quality in this region might be more important than the influence of roads.

Modeling the thermal behavior of multifunctional syntactic foams containing phase change materials for heat management applications

AbstractSyntactic foams are lightweight porous composites obtained by the addition of hollow glass microspheres (HGMs) to a polymer matrix. This work experimentally and numerically investigates the thermal behavior of epoxy‐based syntactic foams with enhanced multifunctionality produced by incorporating microencapsulated phase change materials (PCMs) as functional fillers, providing thermal energy storage and temperature stabilization due to its large latent heat of melting. Foams are fabricated using varying ratios of HGMs (0–40 vol%) and PCM (0–40 vol%) to achieve tuned densities and thermal properties with a total filler content of up to 40 vol%. A one‐dimensional numerical heat transfer model based on the enthalpy method is presented to simulate the thermal behavior of these materials. The model accurately incorporates the specific heat and thermal conductivity of the foam components, as well as the latent heat absorption during PCM melting (up to 68 J/g). The model is experimentally validated by demonstrating good agreement with the measurements of transient temperature profiles during heating tests on the foam samples. The validated tool is then leveraged to model the thermal response of the foams under a sinusoidally varying heat source, similar to the possible real applicative scenarios. These results can help optimize foam compositions balancing energy storage density, heat transfer properties, and structural support for lightweight energy storage systems. Potential applications include high‐efficiency thermal management in battery packs, electronic cooling, solar energy storage, and sustainable temperature‐controlled buildings.Highlights Foams with 0–40 vol% PCM and 0–40 vol% HGM show up to 68 J/g latent heat. 1D numerical model accurately captures thermal conductivity and PCM phase change. Validated model simulates thermal response under sinusoidal heat, optimizing foam composition. Foams act as thermal reservoirs, maintaining up to 5°C lower surface temperatures than epoxy.

Anode humidity trade-offs between proton conductivity and concentration overpotentials in protonic ceramic fuel cell: Experiments and numerical simulations

In protonic ceramic fuel cells (PCFCs), the H2 and H2O partial pressures in the anode side vary along the gas flow direction, particularly during high-fuel-utilization operation. This results in different species conductivities and overpotentials, which renders the quantitative evaluation of local performance based on H2 and H2O mole fractions important. A numerical model is developed that can reflect changes in species conductivities and overpotentials resulting from varying gas mole fractions. The numerical current density–voltage characteristic results obtained numerically agree well with those obtained via measurement in a wide range of H2–H2O gas conditions. Numerical modeling confirms a tradeoff, i.e., higher supply humidity levels result in lower electrolyte resistances but higher concentration overpotentials. The maximum output is achieved at a modest humidification level of 20%. The developed numerical model is particularly useful for optimizing the operating conditions of PCFCs with high fuel utilization.

Analysis of charging performance of thermal energy storage system with graded metal foam structure and active flip method

The latent heat thermal energy storage (LHTES) technology based on solid-liquid phase change material (PCM) is characterized by high energy storage density, small volume change, and constant operation temperature, which is widely employed in waste heat recovery, solar thermal utilization, and equipment thermal management. This paper introduces active flipping and graded porous to strengthen natural convection and heat conduction to alleviate the issue of low thermal conductivity and non-uniform phase change of PCM. Based on the fixed grid system, the enthalpy-porosity method combined with time-dependent gravity and non-Darcy porous effect is employed to solve the solid-liquid phase change problem under different porosity gradients, dimensionless flipping times (t*), and modified Ra (Ra*) numbers. Furthermore, the effects of the Ra* on the optimal t* and porosity gradient are also discussed. The results show that the flipping method can significantly enhance flow and heat transfer within the container, improve temperature field uniformity, and increase the proportion of latent heat storage. With the increase of porosity gradient and t*, the melting time initially decreases and then increases and the optimal thermal performance is achieved at a 6 % porosity gradient and t* = 0.4. Compared to the uniform porous structure without flipping, it can shorten melting time by 49.37 % and improve thermal energy storage rate (TESR) by 76.23 %. Additionally, the optimal porosity gradient is 6 % under different Ra*, but the optimal t* decreases with the increase of Ra*. This paper explores the charging performance of the thermal energy storage system with the graded metal foam structure and active flip method, which can contribute to the study of heat transfer enhancement in LHTES technology.

Novel investigation on adsorption analysis of safranal interacting with boron nitride and aluminum nitride fullerene-like cages: Drug delivery system

This study illustrates the effective control of COVID-19 infection through the adsorption of safranal (SAF) on B16N16 and Al16N16 fullerene-like cages. The SAF adsorption onto the B16N16 and Al16N16 surfaces in gas, water (H2O), and chloroform (CHCl3) environments were assessed using density functional theory (DFT) and time-dependent (TD) density functional theory methods, analyzing the substrates and their complexes. The Al16N16/SAF complex exhibited the most negative binding energy and structural stability in the water phase compared to the B16N16/SAF complex at the PBE0-D3 level. The thermodynamic parameters indicated that the adsorption of SAF onto the fullerene-like cages is exothermic, particularly for the Al16N16/SAF complex. Additionally, the interaction of SAF with the fullerene-like cages in the water phase is more pronounced than in gas and chloroform environments. The complexes' energy gap (Eg) decreases in all three environments compared to the perfect systems, with a significant reduction of over 21 % in all phases. This substantial decrease in the energy gap suggests that the complexes have increased reactivity and sensitivity to SAF, likely due to a significant change in electronic conductivity. The results of molecular docking indicate that the Al16N16/SAF complex in the water phase exhibited a strong binding affinity compared to the other compounds studied. These findings suggest that the Al16N16/SAF complex holds promise as a potential inhibitor for COVID-19 and as a valuable material for biomedical applications and drug delivery systems.

Transient characteristics of ultra-high frequency adjustable multi-pulse gas tungsten welding arc

In response to the shortcomings of traditional Gas Tungsten Arc Welding (GTAW), such as low penetration, slow welding speed, and low production efficiency, an Ultra-High-Frequency Adjustable Multi-Pulse Gas Tungsten Arc Welding (UFMP-GTAW) process is proposed. This process more effectively concentrates the temperature distribution of the welding arc. To characterize the arc morphology and its dynamic changes, high-speed photography captured ten images of the UFMP-GTAW welding arc within one cycle. The arc image processing algorithm proposed in the paper was used to study the arc's variation characteristics over one cycle. This algorithm includes binarization, arc segmentation, and edge detection to obtain arc morphology parameters. The arc symmetry algorithm is used to symmetrize the arc images for Abel inversion, resulting in the emission coefficient distribution. Further calculations provide the temperature distribution, electrical conductivity distribution, and current density distribution of the arc. Analysis reveals that changes in arc temperature, electrical conductivity, and current density lag behind changes in current. The temperature of the arc spreads from the central axis to the surrounding arc space. When high-frequency current variations occur, the heat input generated by the current increase takes time to transfer to the entire arc space. Conversely, if the current suddenly decreases, the heat input rapidly diminishes. However, because heat transfer takes time, the arc space remains relatively stable for a short period, making the ultra-high-frequency arc form more stable.

The electric-field-induced birefringence of hexagonal Cu1.81S flakes influenced by hole carriers

In this work, regular hexagonal copper sulfide (Cu1.81S) flakes are fabricated in two sizes by controlling the dosage of octadecene (ODE). Significant electric-field-induced birefringence of their dispersions is observed, benefitting from the anisotropic shape and the mobility of the hole carriers. The sudden increase and the relative inversion of the electric-field-induced birefringence Δn for the two sizes can be explained by both the constraint of polarized carriers and an increasing electric field. The dominance of the hole carriers in the electric-field-induced birefringence of Cu1.81S flakes is proved by decoration with silver nanoparticles and the corresponding conductivity changes.

A Deep Learning Estimation for Probing Depth of Transient Electromagnetic Observation

The probing depth of the transient electromagnetic method (TEM) refers to the depth range at which the underground conductivity changes can be effectively detected. It typically ranges from tens of meters to several kilometers and is influenced by factors such as instrument parameters and the conductivity of the subsurface structure. Rapid and accurate probing depth is useful for the selection of appropriate inversion parameters and improving survey accuracy. However, mainstream methods suffer from issues such as low computational precision, large uncertainties, or high computational requirements, making them unsuitable for processing massive airborne electromagnetic data. In this study, we propose a prediction model based on deep learning that can directly compute the probing depth from the TEM responses, and its effectiveness and accuracy are validated through synthetic models and field measurements. We compared the performance of classic deep learning models, including CNN, RESNET, and RNN, and found that RNN performed the best overall on both synthetic and field data. Furthermore, we apply this algorithm to deep learning-based ATEM inversion by constraining the one-dimensional resistivity model depths in the training set, to reduce the non-uniqueness of the inversion, accelerate the convergence, and improve its prediction accuracy.

Complete degradation of propranolol by a water falling film non-thermal plasma reactor: The effects of input power and plasma gases on transformation pathway

Propranolol, a beta-blocker, is a widely used drug for cardiovascular diseases. A synthetic sample containing propranolol (PRO) solution at native pH was recirculated up to ten times through an original coaxial non-thermal plasma reactor with a water falling film. Different discharge conditions, feed gasses, and power greatly influenced the extent of PRO degradation and the abundance of degradation products. The highest degradation rates were achieved in Ar plasma, either pure or in a mixture with O2, with over 70% of PRO degraded after only two passes through the DBD reactor. The full non-thermal plasma treatment was followed by a minimal change of pH value and conductivity. On the other hand, ambient air as the feed gas resulted in 60% of PRO degradation rate after the full treatment and contributed to a major drop in pH value and an increase in the conductivity of the treated solution. The structures of 47 degradation products in all three gases were identified and the degradation pathway is proposed, supported by DFT methodology. Scavenging experiments demonstrated that hydroxyl radical was predominant when plasma was generated using ambient air and Ar, while it had a minimal effect on the degradation in the mixture of Ar and O2. The desired level of propranolol decomposition was achieved only by the adjustment of the nonchemical parameters of the treatment, such as plasma gas composition and power. These results imply that a non-thermal plasma reactor is a highly effective method for pharmaceutical wastewater treatment, with no catalysts added.

Constructing Si@CN@MXene from silicon waste as high-performance lithium-ion battery anodes

Silicon represents one of the most attractive materials for anodes in lithium-ion batteries (LIBs) due to highest theoretical specific capacity. Thus, there is a most urgent need to prepare Si-based nano materials in a very efficient way, and develop some reasonable approaches for their modification in order to resolve the short-falls of Si anode, which include both low conductivity and huge volume changes during intercalation of lithium ions. In this work, the kerf loss silicon (KL Si) from the photovoltaic industry has been used as an inexpensive Si source for the synthesis of the Si@CN@MXene (SCM) composite to be applied as an anode material. Meanwhile, the chitosan works as the charge bridge in sequence with the Si and MXene nanosheets under electrostatic force during composite preparation. The MXene nanosheet and N-doped carbon layer that build up during chitosan calcination can be attributed to forming a hierarchical high-speed conductive network over the surface of silicon, which contributed to alleviate the volume expansion of silicon. The SCM electrode discharge capacity was obtained at a stable value of 900.8 mAh g−1 at 0.5 A g−1, 861.9 mA g−1 at 1 A g−1 and 657.6 mA g−1 even at 2 A g−1 after 100 cycles. The SCM electrode also exhibited good rate performance from 0.2 to 5 A g−1. Therefore, this study recommends that the method is very promising for producing the silicon anode material for LIBs from KL Si.

First-principles study on thermal transport properties of GaN under different cross-plane strain

With the development of power devices towards high integration and power, the electrical and thermal stresses per unit area become more concentrated and intensified. The impact of cross-plane strain resulting from inverse piezoelectric effect and thermal expansion on power devices cannot be ignored. Cross-plane strain has a substantial influence on the thermal properties of GaN. However, the research on the influence of cross-plane strain on the thermal conductivity of GaN has not been reported in the literature. Based on the first-principles calculation method and the phonon Boltzmann transport equation, the influence of cross-plane strain on the thermal conductivity and phonon characteristics of the GaN lattice is systematically studied in this study. The thermal conductivity of GaN has anisotropy and increases significantly with the decrease in temperature. The thermal conductivity of GaN at room temperature under the free state is calculated to be 257 and 275 W/(m·K) for in-plane (k⊥) and cross-plane (k∥) directions, respectively. Compared with previous theoretical reports, our calculation results are more consistent with the existing experiment values. Under the state of cross-plane strain, the lattice thermal conductivity changes remarkably. In detail, the average thermal conductivity at room temperature decreased by 35 % under a 5 % cross-plane tensile strain state, while it increased by 11.5 % under a 5 % cross-plane compressive strain state. According to the calculation results, the influence of cross-plane on lattice thermal conductivity is mainly due to the change in phonon lifetime. The analysis of two mechanisms of phonon lifetime suppression indicates that the cross-plane strain will significantly change the frequency of the high-frequency optical acoustic branch. This result leads to a change in the phonon scattering process and thus affects the phonon lifetime. Besides, the anisotropy of thermal conductivity changes under different strain values, which may be due to the weakened piezoelectric polarization effect induced by strain.