The superconducting magnet system of a fusion reactor plays a vital role in plasma confinement,a process that can be dis-rupted by various operational factors.A critical parameter for evaluating the temperature margin...The superconducting magnet system of a fusion reactor plays a vital role in plasma confinement,a process that can be dis-rupted by various operational factors.A critical parameter for evaluating the temperature margin of superconducting magnets during normal operation is the nuclear heating caused by D-T neutrons.This study investigates the impact of nuclear heat-ing on a superconducting magnet system by employing an improved analysis method that combines neutronics and thermal hydraulics.In the magnet system,toroidal field(TF)magnets are positioned closest to the plasma and bear the highest nuclear-heat load,making them prime candidates for evaluating the influence of nuclear heating on stability.To enhance the modeling accuracy and facilitate design modifications,a parametric TF model that incorporates heterogeneity is established to expedite the optimization design process and enhance the accuracy of the computations.A comparative analysis with a homogeneous TF model reveals that the heterogeneous model improves accuracy by over 12%.Considering factors such as heat load,magnetic-field strength,and cooling conditions,the cooling circuit facing the most severe conditions is selected to calculate the temperature of the superconductor.This selection streamlines the workload associated with thermal-hydraulic analysis.This approach enables a more efficient and precise evaluation of the temperature margin of TF magnets.Moreover,it offers insights that can guide the optimization of both the structure and cooling strategy of superconducting magnet systems.展开更多
Grain-oriented silicon steels were prepared at different heating rates during high temperature annealing,in which the evolution of magnetic properties,grain orientations and precipitates were studied.To illustrate the...Grain-oriented silicon steels were prepared at different heating rates during high temperature annealing,in which the evolution of magnetic properties,grain orientations and precipitates were studied.To illustrate the Zener factor,the diameter and number density of precipitates of interrupted testing samples were statistically calculated.The effect of precipitate ripening on the Goss texture and magnetic property was investigated.Data indicated that the trend of Zener factor was similar under different heating rates,first increasing and then decreasing,and that the precipitate maturing was greatly inhibited as the heating rate increased.Secondary recrystallization was developed at the temperature of 1010℃when a heating rate of 5℃/h was used,resulting in Goss,Brass and{110}<227>oriented grains growing abnormally and a magnetic induction intensity of 1.90T.Furthermore,increasing the heating rate to 20℃/h would inhibit the development of undesirable oriented grains and obtain a sharp Goss texture.However,when the heating rate was extremely fast,such as 40℃/h,poor secondary recrystallization was developed with many island grains,corresponding to a decrease in magnetic induction intensity to 1.87 T.At a suitable heating rate of 20℃/h,the sharpest Goss texture and the highest magnetic induction of 1.94 T with an onset secondary recrystallization temperature of 1020℃were found among the experimental variables in this study.The heating rate affected the initial temperature of secondary recrystallization by controlling the maturation of precipitates,leading to the deviation and dispersion of Goss texture,thereby reducing the magnetic properties.展开更多
Thermal quenching(TQ)at elevated temperature is a major factor affecting the luminescent intensity and efficiency of phosphors.Improving the thermal stability of phosphors and weakening the TQ effect are of significan...Thermal quenching(TQ)at elevated temperature is a major factor affecting the luminescent intensity and efficiency of phosphors.Improving the thermal stability of phosphors and weakening the TQ effect are of significance for the high-quality illumination of phosphor-converted WLEDs.Here,a novel red-emitting phosphor K_(2)Zn(PO_(3))_(4)∶Mn^(2+)is synthesized by standard high temperature solid state reaction in ambient atmosphere,which is a new member of self-reduction system.An effective synthesis strategy is proposed to optimize its photoluminescent performances.Combined with X-ray photoelectron spectroscopy and X-ray absorption fine structure spectroscopy,oxygen vacancy defects introduced by Mn doping are proved to play an important role in the transition of Mn^(4+)→Mn^(2+).Thermoluminescence analysis reveals that the distribution of trap levels,especially the deep ones,is effectively regulated by the controllable crystallization and significantly affect the thermal stability of phosphors.Then a defect-assisted model is proposed to address the inner mechanism of the phenomenon.The carriers trapped by deep trap levels can be released under the high-temperature stimulus,which return back to the luminescent centers and participate in the radiative recombination to improve thermal stability.This study provides a new crystallographic idea and theoretical support for obtaining luminescent materials with high thermal stability.展开更多
Due to the complex high-temperature characteristics of hydrocarbon fuel,the research on the long-term working process of parallel channel structure under variable working conditions,especially under high heat-mass rat...Due to the complex high-temperature characteristics of hydrocarbon fuel,the research on the long-term working process of parallel channel structure under variable working conditions,especially under high heat-mass ratio,has not been systematically carried out.In this paper,the heat transfer and flow characteristics of related high temperature fuels are studied by using typical engine parallel channel structure.Through numeri⁃cal simulation and systematic experimental verification,the flow and heat transfer characteristics of parallel chan⁃nels under typical working conditions are obtained,and the effectiveness of high-precision calculation method is preliminarily established.It is known that the stable time required for hot start of regenerative cooling engine is about 50 s,and the flow resistance of parallel channel structure first increases and then decreases with the in⁃crease of equivalence ratio(The following equivalence ratio is expressed byΦ),and there is a flow resistance peak in the range ofΦ=0.5~0.8.This is mainly caused by the coupling effect of high temperature physical proper⁃ties,flow rate and pressure of fuel in parallel channels.At the same time,the cooling and heat transfer character⁃istics of parallel channels under some conditions of high heat-mass ratio are obtained,and the main factors affect⁃ing the heat transfer of parallel channels such as improving surface roughness and strengthening heat transfer are mastered.In the experiment,whenΦis less than 0.9,the phenomenon of local heat transfer enhancement and deterioration can be obviously observed,and the temperature rise of local structures exceeds 200℃,which is the risk of structural damage.Therefore,the reliability of long-term parallel channel structure under the condition of high heat-mass ratio should be fully considered in structural design.展开更多
In order to increase the stability of the Mongolia power system, a single-phase automatic reclosing device (SPAR) was introduced on double-circuit power lines built with a size of 330 kV, operating on a voltage of 220...In order to increase the stability of the Mongolia power system, a single-phase automatic reclosing device (SPAR) was introduced on double-circuit power lines built with a size of 330 kV, operating on a voltage of 220 kV and a length of 250 km. These overhead power lines (L-213, L-214) connect the 220/110/35 kV “Songino” substation with the “Mandal” substation and form system networks. This paper presents the challenges encountered when implementing single-phase automatic reclosing (SPAR) devices and compares the changes in power system parameters before and after SPAR deployment for a long 220 kV line. Simulations and analyses were carried out using DIgSILENT PowerFactory software, focusing on rotor angle stability, and the overall impact on the power system during short-circuit faults. The evaluation also utilized measurement data from the Wide Area Monitoring System (WAMS) to compare system behavior pre- and post-implementation of SPAR. The findings reveal that SPAR significantly enhances system reliability and stability, effectively mitigating the risk of oscillations and stability loss triggered by short circuits. This improvement contributes to a more resilient power system, reducing the potential for disturbances caused by faults.展开更多
Heat treatment processes, such as annealing and quenching, are crucial in determining residual stress evolution, microstructural changes and mechanical properties of metallic materials, with residual stresses playing ...Heat treatment processes, such as annealing and quenching, are crucial in determining residual stress evolution, microstructural changes and mechanical properties of metallic materials, with residual stresses playing a greater role in the performance of components. This paper investigates the effect of heat treatment on residual stresses induced in AISI 1025, manufactured using LENS. Finite element model was developed and simulated to analyze residual stress development. AISI 1025 samples suitable for tool and die applications in Fused Deposition Modelling (FDM) filament production, were fabricated using Laser Engineered Net Shaping (LENS) process, followed by heat treatment where annealing and quenching processes were done. The material’s microstructure, residual stress and hardness of heat-treated samples under investigation, were compared against the as-built samples. The results indicated that after annealing, tensile residual stresses were reduced by 93%, resulting in a reduced crack growth rate, compared to the as-built sample, although the hardness was reduced significantly by 25%. On the other hand, high tensile residual stresses of 425 ± 14 MPa were recorded after quenching process with an improvement of hardness by 21%.展开更多
Predicting the material stability is essential for accelerating the discovery of advanced materials in renewable energy, aerospace, and catalysis. Traditional approaches, such as Density Functional Theory (DFT), are a...Predicting the material stability is essential for accelerating the discovery of advanced materials in renewable energy, aerospace, and catalysis. Traditional approaches, such as Density Functional Theory (DFT), are accurate but computationally expensive and unsuitable for high-throughput screening. This study introduces a machine learning (ML) framework trained on high-dimensional data from the Open Quantum Materials Database (OQMD) to predict formation energy, a key stability metric. Among the evaluated models, deep learning outperformed Gradient Boosting Machines and Random Forest, achieving up to 0.88 R2 prediction accuracy. Feature importance analysis identified thermodynamic, electronic, and structural properties as the primary drivers of stability, offering interpretable insights into material behavior. Compared to DFT, the proposed ML framework significantly reduces computational costs, enabling the rapid screening of thousands of compounds. These results highlight ML’s transformative potential in materials discovery, with direct applications in energy storage, semiconductors, and catalysis.展开更多
This study presents a novel method to evaluate the safety of open-pit slopes by means of three-dimensional numerical modeling with the finite difference method. The method presented here uses a block model as a vehicl...This study presents a novel method to evaluate the safety of open-pit slopes by means of three-dimensional numerical modeling with the finite difference method. The method presented here uses a block model as a vehicle to carry relevant information from the rock mass and automatically construct the numerical model. The results suggest that the method is promising because of its capacity to accurately incorporate a large amount of high-complexity rock data by considering spatial location and material behavior. It is expected that the innovations in this method will make the design, construction, and operation of open-pit iron mines safer and more economical.展开更多
This study develops an analytical model to evaluate the cooling performance of a porous terracotta tubular direct evaporative heat and mass exchanger. By combining energy and mass balance equations with heat and mass ...This study develops an analytical model to evaluate the cooling performance of a porous terracotta tubular direct evaporative heat and mass exchanger. By combining energy and mass balance equations with heat and mass transfer coefficients and air psychrometric correlations, the model provides insights into the impact of design and operational parameters on the exchanger cooling performance. Validated against an established numerical model, it accurately simulates cooling behavior with a Root Mean Square Deviation of 0.43 - 1.18˚C under varying inlet air conditions. The results show that tube geometry, including equivalent diameter, flatness ratio, and length significantly influences cooling outcomes. Smaller diameters enhance wet-bulb effectiveness but reduce cooling capacity, while increased flatness and length improve both. For example, extending the flatness ratio of a 15 mm diameter, 0.6 m long tube from 1 (circular) to 4 raises the exchange surface area from 0.028 to 0.037 m2, increasing wet-bulb effectiveness from 60% to 71%. Recommended diameters range from 5 mm for tubes under 0.5 m to 1 cm for tubes 0.5 to 1 m in length. Optimal air velocities depend on tube length: 1 m/s for tubes under 0.8 m, 1.5 m/s for lengths of 0.8 to 1.2 m, and up to 2 m/s for longer tubes. This model offers a practical alternative to complex numerical and CFD methods, with potential applications in cooling tower optimization for thermal and nuclear power plants and geothermal heat exchangers.展开更多
The behavior of single-phase flow and conjugate heat transfer in micro-channel heat sinks(MCHS)subjected to auniform heat flux is investigated by means of numerical simulations.Various geometrical configurations areex...The behavior of single-phase flow and conjugate heat transfer in micro-channel heat sinks(MCHS)subjected to auniform heat flux is investigated by means of numerical simulations.Various geometrical configurations areexamined,particularly,the combinations of rectangular solid and perforated blocks,used to create a disturbancein the flow.The analysis focuses on several key aspects and related metrics,including the temperature distribution,the mean Fanning friction factor,the pressure drop,the Nusselt number,and the overall heat transfer coefficientacross a range of Reynolds numbers(80–870).It is shown that the introduction of such blocks significantlyenhances the heat transfer performances of the MCHS compared to the straight-through flow channel.Specifically,a case is found where the Nusselt number increases by 2.3 times relative to the reference case.The integrationof perforated blocks facilitates the generation of vorticity within the channel,promoting the mixing of coldand hot fluids.Notably,MCHS incorporating perforated rectangular blocks exhibit more pronounced heat transferbenefits at Reynolds numbers smaller than 400.展开更多
BACKGROUND Pain in the back or pelvis or fear of back pain may affect the timing or cocontraction of the core muscles.In both static and dynamic movements,the Sahrmann core stability test provides an assessment of cor...BACKGROUND Pain in the back or pelvis or fear of back pain may affect the timing or cocontraction of the core muscles.In both static and dynamic movements,the Sahrmann core stability test provides an assessment of core muscle activation and a person's ability to stabilize the lumbopelvic complex.Preparatory cues and images can be used to increase the activation of these muscles.To attain optimal movement patterns,it will be necessary to determine what cueing will give the most effective results for core stability.AIM To investigate the effects of external and internal cues on core muscle activation during the Sahrmann five-level core stability test.METHODS Total 68 participants(21.83±3.47 years)were randomly allocated to an external(n=35)or internal cue group(n=33).Participants performed the Sahrmann fivelevel core stability test without a cue as baseline and the five-level stability exercises with an internal or external cue.External cue group received a pressure biofeedback unit(PBU),and the internal cue group received an audio cue.A Delsys Trigno^(TM)surface electromyography unit was used for muscle activation from the rectus abdominis,external oblique,and transverse abdominis/internal oblique muscles.RESULTS Linear mixed effects model analysis showed that cueing had a significant effect on core muscle activation(P=0.001);however,there was no significant difference between cue types(internal or external)(P=0.130).CONCLUSION Both external and internal cueing have significant effects on core muscle activation during the Sahrmann five-level core stability test and the PBU does not create higher muscle activation than internal cueing.展开更多
Tomato(Solanum lycopersicum)is an important fruit and vegetable crop in worldwide.The fertility of tomato reproductive organs can be dramatically decreased when ambient temperatures rise above 35°C,reducing tomat...Tomato(Solanum lycopersicum)is an important fruit and vegetable crop in worldwide.The fertility of tomato reproductive organs can be dramatically decreased when ambient temperatures rise above 35°C,reducing tomato fruit yield.It is necessary to identify transcription factors(TFs)and target genes involved in heat stress response(HSR)signaling cascades in tomato flower buds to improve tomato plant thermotolerance.In this study,we profiled genes expressed in three developmental stages of tomato flower buds.Red and turquoise modules for heat stress(HS)were identified through gene co-expression network analysis,and the genes within these modules were enriched in HS-related pathways.By focusing on the TFs in the two modules,we identified several novel HSR-related TFs,including SlWRKY75,SlMYB117,and SlNAM.Furthermore,homology analysis illustrated a conserved signaling cascade in tomato.Lastly,we identified and experimentally validated four HSF-regulated genes,namely SlGrpE,SlERDJ3A,SlTIL,and SlPOM1,that likely modulate thermotolerance in plants.These results provide a high-resolution atlas of gene expression during tomato flower bud development under HS conditions,which is a valuable resource for uncovering potential regulatory networks associated with the HSR in tomato.展开更多
Extremely high temperatures resulting from climate change have become a major challenge for increasing rice production.Therefore,our objective was to develop heat-tolerant aromatic rice varieties using the pedigree me...Extremely high temperatures resulting from climate change have become a major challenge for increasing rice production.Therefore,our objective was to develop heat-tolerant aromatic rice varieties using the pedigree method,focusing on selecting for seed-setting ability under extremely high temperatures along with the use of single nucleotide polymorphism/insertion and deletion(SNP/InDel)markers to improve aromatic properties and grain quality.Furthermore,the QTL-seq approach was utilized to identify QTLs for seed-setting rate in an F2 population subjected to heat stress.The candidate QTL regions were then aligned to confirm SNPs/InDels in synonymous F7 candidate heat-tolerant lines.The results revealed that four promising lines,namely 84-7-1-9,84-7-1-10,159-3-3-1,and 159-3-3-10,were classified as heat-tolerant with low amylose content.In addition,lines 84-7-1-9 and 84-7-1-10 were identified as aromatic rice encompassing the aroma gene(badh2).Regarding the QTL-seq results,the qSF2.1 region ranged from 311051 to 3929422 bp on chromosome 2,was identified based on the highest contrasting SNP index between the heat-susceptible and tolerant bulks.The candidate genes within this region include two genes related to heat shock proteins,three genes associated with pollen fertility,and four genes involved in heat stress and other abiotic stress responses.These genes are proposed as potential candidates for heat tolerance and could serve as targets in rice breeding programs aimed at enhancing heat tolerance.展开更多
Plant diversity plays a crucial role in maintaining the stability of ecological function.Based on field investigations and experimental analyses,artificial grassland plots with varying sowing times,adjacent natural gr...Plant diversity plays a crucial role in maintaining the stability of ecological function.Based on field investigations and experimental analyses,artificial grassland plots with varying sowing times,adjacent natural grassland(CK),and open-pit coal mine dumps in the Muli mining area of Qinghai Province were selected as research subjects for this study.The characteristics of plant diversity and community stability were measured and analyzed,and the relationships between these factors and their influencing variables were evaluated.The results indicated significant differences in the vegetation community characteristics and plant diversity among the various grasslands.Coverage,aboveground biomass,belowground biomass,soil total nitrogen,and soil total carbon were the highest when the growth period was three years.Plant diversity and community stability in the natural grassland were significantly greater than that in the artificial grassland and open-pit coal mine dumps.A significant positive correlation was observed between plant diversity and community stability,suggesting that plant diversity can serve as an index of community stability.The order of stability,from highest to lowest,was CK>11a>10a>8a>9a>6a>7a>3a>2a>1a>0a.Years were identified as the primary factors affecting plant diversity and community stability by altering the soil pH.These results elucidate the relationships and driving mechanisms between plant diversity and community stability in grasslands,providing a scientific basis for maintaining community stability in artificial grassland ecosystems in alpine mining areas.展开更多
Global warming impacts plant growth and development,which in turn threatens food security.Plants can clearly respond to warm-temperature(such as by thermomorphogenesis)and high-temperature stresses.At the molecular le...Global warming impacts plant growth and development,which in turn threatens food security.Plants can clearly respond to warm-temperature(such as by thermomorphogenesis)and high-temperature stresses.At the molecular level,many small molecules play crucial roles in balancing growth and defense,and stable high yields can be achieved by fine-tuning the responses to external stimuli.Therefore,it is essential to understand the molecular mechanisms underlying plant growth in response to heat stress and how plants can adjust their biological processes to survive heat stress conditions.In this review,we summarize the heat-responsive genetic networks in plants and crop plants based on recent studies.We focus on how plants sense the elevated temperatures and initiate the cellular and metabolic responses that allow them to adapt to the adverse growing conditions.We also describe the trade-off between plant growth and responses to heat stress.Specifically,we address the regulatory network of plant responses to heat stress,which will facilitate the discovery of novel thermotolerance genes and provide new opportunities for agricultural applications.展开更多
Fe(Al,Ta)/Fe_(2)Ta(Al)eutectic composites with solidification rates of 6,20,30,and 80μm/s were prepared by a modified Bridgman directional solidification technology.The coarse Fe_(2)Ta(Al)Laves phase was precipitated...Fe(Al,Ta)/Fe_(2)Ta(Al)eutectic composites with solidification rates of 6,20,30,and 80μm/s were prepared by a modified Bridgman directional solidification technology.The coarse Fe_(2)Ta(Al)Laves phase was precipitated at the eutectic colony boundary during the solidification process,which can affect the stability of microstructure and properties of the composites.The coarse Laves phase was refined using different heat treatment processes in the present paper.The influences of different heat treatment parameters on the Laves phase content,lamella/rod spacing,and mechanical properties were investigated in detail.In addition,the corrosion behaviors of Fe(Al,Ta)/Fe_(2)Ta(Al)eutectic composites before and after being annealed heat treatment in a 3 g/L Na_(2)S_(2)O_(3)solution were also studied.It is shown that both the content of Laves phase and lamella/rod spacing are gradually decreased after heat treatment.Micro-hardness is decreased,while the yield strength,compressive strength,and corrosion resistance are improved.The optimum heat treatment process is selected as well.展开更多
In this paper,we establish a stability estimate for the isoperimetric inequality of horospherically convex domains in hyperbolic plane.This estimate involves a relationship between the Hausdorff distance to a geodesic...In this paper,we establish a stability estimate for the isoperimetric inequality of horospherically convex domains in hyperbolic plane.This estimate involves a relationship between the Hausdorff distance to a geodesic ball and the deficit in the isoperimetric inequality,where the coefficient of the deficit is a universal constant.展开更多
This paper establishes an amplitude modulation heating model, simulating the far-field radiation of ELF/VLF signals generated by modulation heating, as well as the specific location and longitudinal extent of the radi...This paper establishes an amplitude modulation heating model, simulating the far-field radiation of ELF/VLF signals generated by modulation heating, as well as the specific location and longitudinal extent of the radiation source. We consider various modulation waveforms and find that square-wave modulation has the highest excitation efficiency for ELF/VLF signals, and that square-wave modulation with a smaller duty cycle(<50%) exhibits higher excitation efficiency for ELF/VLF signals, while the sin^(2)t waveform modulation yields the lowest proportion of harmonic energy in the generated signals. The amplitude of the second harmonic generated by the sin^(2)t waveform is less than one-tenth that of the fundamental frequency, and the energy of higher-frequency harmonics can be negligibly small compared with those of the fundamental wave. It is a challenging task to achieve a balance between enhancing the excitation efficiency of ELF/VLF signals and also suppressing harmonics generated by the modulated heating process. This is because the harmonics are correspondingly enhanced as the excitation efficiency of the signals is increased. However, we find that under conditions of varying effective radiant power and modulation frequency, as long as the modulation waveform is unchanged, the energy ratio between the fundamental frequency signal generated by modulated heating and each harmonic is relatively fixed, with changes only in signal intensity and the location of the radiation source zone. This implies that one can first select modulation waveforms that make the signal less prone to distortion, then increase the effective radiated power to enhance the signal strength, without concern for harmonic interference of the fundamental signal.展开更多
Heat stress causes overgrowth,leaf dryness and fruit malformation,which negatively impacts cucumber quality and yield.Yet,in spite of the devastating consequences of this abiotic stress,few genes for heat tolerance in...Heat stress causes overgrowth,leaf dryness and fruit malformation,which negatively impacts cucumber quality and yield.Yet,in spite of the devastating consequences of this abiotic stress,few genes for heat tolerance in cucumber have been identified.Here,the heat injury indices of 88 cucumber accessions representing diverse ecotypes were collected in two open-field environments,with naturally occurring high temperatures over two years.Seventeen of the 88 accessions were identified as highly heat-tolerant.Using a genome-wide association study,five loci(gHII3.1,gHII3.2,gHII3.3,gHII4.1 and gHII6.1)on three chromosomes associated with heat tolerance were detected.Pairwise linkage disequilibrium correlation,sequence polymorphisms,and qRT-PCR analyses at these loci,identified five candidate genes predicted to be casual for heat stress response in cucumber.CsaV3_3G04883,CsaV3_4G029050 and CsaV3_6G005370 each had nonsynonymous SNPs,and were significantly up-regulated by heat stress in the heat-tolerant genotypes.CsaV3_3G031890 was also induced by heat stress,but in the heatsensitive genotypes,and sequence polymorphism was only found in the promoter region.Identifying these candidate genes lays a foundation for understanding cucumber thermotolerance mechanisms.Our study is one of the few to examine heat stress in adult cucumber plants and it therefore fills a critical gap in knowledge.It is also an important first-step towards accelerating the breeding of robust heat-tolerant varieties.展开更多
Backfill is often employed in mining operations for ground support,with its positive impact on ground stability acknowledged in many underground mines.However,existing studies have predominantly focused only on the st...Backfill is often employed in mining operations for ground support,with its positive impact on ground stability acknowledged in many underground mines.However,existing studies have predominantly focused only on the stress development within the backfill material,leaving the influence of stope backfilling on stress distribution in surrounding rock mass and ground stability largely unexplored.Therefore,this paper presents numerical models in FLAC3D to investigate,for the first time,the time-dependent stress redistribution around a vertical backfilled stope and its implications on ground stability,considering the creep of surrounding rock mass.Using the Soft Soil constitutive model,the compressibility of backfill under large pressure was captured.It is found that the creep deformation of rock mass exercises compression on backfill and results in a less void ratio and increased modulus for fill material.The compacted backfill conversely influenced the stress distribution and ground stability of rock mass which was a combined effect of wall creep and compressibility of backfill.With the increase of time or/and creep deformation,the minimum principal stress in the rocks surrounding the backfilled stope increased towards the pre-mining stress state,while the deviatoric stress reduces leading to an increased factor of safety and improved ground stability.This improvement effect of backfill on ground stability increased with the increase of mine depth and stope height,while it is also more pronounced for the narrow stope,the backfill with a smaller compression index,and the soft rocks with a smaller viscosity coefficient.Furthermore,the results emphasize the importance of minimizing empty time and backfilling extracted stope as soon as possible for ground control.Reduction of filling gap height enhances the local stability around the roof of stope.展开更多
基金the National Natural Science Foundation of China(Nos.52222701,52077211,and 52307034).
文摘The superconducting magnet system of a fusion reactor plays a vital role in plasma confinement,a process that can be dis-rupted by various operational factors.A critical parameter for evaluating the temperature margin of superconducting magnets during normal operation is the nuclear heating caused by D-T neutrons.This study investigates the impact of nuclear heat-ing on a superconducting magnet system by employing an improved analysis method that combines neutronics and thermal hydraulics.In the magnet system,toroidal field(TF)magnets are positioned closest to the plasma and bear the highest nuclear-heat load,making them prime candidates for evaluating the influence of nuclear heating on stability.To enhance the modeling accuracy and facilitate design modifications,a parametric TF model that incorporates heterogeneity is established to expedite the optimization design process and enhance the accuracy of the computations.A comparative analysis with a homogeneous TF model reveals that the heterogeneous model improves accuracy by over 12%.Considering factors such as heat load,magnetic-field strength,and cooling conditions,the cooling circuit facing the most severe conditions is selected to calculate the temperature of the superconductor.This selection streamlines the workload associated with thermal-hydraulic analysis.This approach enables a more efficient and precise evaluation of the temperature margin of TF magnets.Moreover,it offers insights that can guide the optimization of both the structure and cooling strategy of superconducting magnet systems.
文摘Grain-oriented silicon steels were prepared at different heating rates during high temperature annealing,in which the evolution of magnetic properties,grain orientations and precipitates were studied.To illustrate the Zener factor,the diameter and number density of precipitates of interrupted testing samples were statistically calculated.The effect of precipitate ripening on the Goss texture and magnetic property was investigated.Data indicated that the trend of Zener factor was similar under different heating rates,first increasing and then decreasing,and that the precipitate maturing was greatly inhibited as the heating rate increased.Secondary recrystallization was developed at the temperature of 1010℃when a heating rate of 5℃/h was used,resulting in Goss,Brass and{110}<227>oriented grains growing abnormally and a magnetic induction intensity of 1.90T.Furthermore,increasing the heating rate to 20℃/h would inhibit the development of undesirable oriented grains and obtain a sharp Goss texture.However,when the heating rate was extremely fast,such as 40℃/h,poor secondary recrystallization was developed with many island grains,corresponding to a decrease in magnetic induction intensity to 1.87 T.At a suitable heating rate of 20℃/h,the sharpest Goss texture and the highest magnetic induction of 1.94 T with an onset secondary recrystallization temperature of 1020℃were found among the experimental variables in this study.The heating rate affected the initial temperature of secondary recrystallization by controlling the maturation of precipitates,leading to the deviation and dispersion of Goss texture,thereby reducing the magnetic properties.
文摘Thermal quenching(TQ)at elevated temperature is a major factor affecting the luminescent intensity and efficiency of phosphors.Improving the thermal stability of phosphors and weakening the TQ effect are of significance for the high-quality illumination of phosphor-converted WLEDs.Here,a novel red-emitting phosphor K_(2)Zn(PO_(3))_(4)∶Mn^(2+)is synthesized by standard high temperature solid state reaction in ambient atmosphere,which is a new member of self-reduction system.An effective synthesis strategy is proposed to optimize its photoluminescent performances.Combined with X-ray photoelectron spectroscopy and X-ray absorption fine structure spectroscopy,oxygen vacancy defects introduced by Mn doping are proved to play an important role in the transition of Mn^(4+)→Mn^(2+).Thermoluminescence analysis reveals that the distribution of trap levels,especially the deep ones,is effectively regulated by the controllable crystallization and significantly affect the thermal stability of phosphors.Then a defect-assisted model is proposed to address the inner mechanism of the phenomenon.The carriers trapped by deep trap levels can be released under the high-temperature stimulus,which return back to the luminescent centers and participate in the radiative recombination to improve thermal stability.This study provides a new crystallographic idea and theoretical support for obtaining luminescent materials with high thermal stability.
文摘Due to the complex high-temperature characteristics of hydrocarbon fuel,the research on the long-term working process of parallel channel structure under variable working conditions,especially under high heat-mass ratio,has not been systematically carried out.In this paper,the heat transfer and flow characteristics of related high temperature fuels are studied by using typical engine parallel channel structure.Through numeri⁃cal simulation and systematic experimental verification,the flow and heat transfer characteristics of parallel chan⁃nels under typical working conditions are obtained,and the effectiveness of high-precision calculation method is preliminarily established.It is known that the stable time required for hot start of regenerative cooling engine is about 50 s,and the flow resistance of parallel channel structure first increases and then decreases with the in⁃crease of equivalence ratio(The following equivalence ratio is expressed byΦ),and there is a flow resistance peak in the range ofΦ=0.5~0.8.This is mainly caused by the coupling effect of high temperature physical proper⁃ties,flow rate and pressure of fuel in parallel channels.At the same time,the cooling and heat transfer character⁃istics of parallel channels under some conditions of high heat-mass ratio are obtained,and the main factors affect⁃ing the heat transfer of parallel channels such as improving surface roughness and strengthening heat transfer are mastered.In the experiment,whenΦis less than 0.9,the phenomenon of local heat transfer enhancement and deterioration can be obviously observed,and the temperature rise of local structures exceeds 200℃,which is the risk of structural damage.Therefore,the reliability of long-term parallel channel structure under the condition of high heat-mass ratio should be fully considered in structural design.
文摘In order to increase the stability of the Mongolia power system, a single-phase automatic reclosing device (SPAR) was introduced on double-circuit power lines built with a size of 330 kV, operating on a voltage of 220 kV and a length of 250 km. These overhead power lines (L-213, L-214) connect the 220/110/35 kV “Songino” substation with the “Mandal” substation and form system networks. This paper presents the challenges encountered when implementing single-phase automatic reclosing (SPAR) devices and compares the changes in power system parameters before and after SPAR deployment for a long 220 kV line. Simulations and analyses were carried out using DIgSILENT PowerFactory software, focusing on rotor angle stability, and the overall impact on the power system during short-circuit faults. The evaluation also utilized measurement data from the Wide Area Monitoring System (WAMS) to compare system behavior pre- and post-implementation of SPAR. The findings reveal that SPAR significantly enhances system reliability and stability, effectively mitigating the risk of oscillations and stability loss triggered by short circuits. This improvement contributes to a more resilient power system, reducing the potential for disturbances caused by faults.
文摘Heat treatment processes, such as annealing and quenching, are crucial in determining residual stress evolution, microstructural changes and mechanical properties of metallic materials, with residual stresses playing a greater role in the performance of components. This paper investigates the effect of heat treatment on residual stresses induced in AISI 1025, manufactured using LENS. Finite element model was developed and simulated to analyze residual stress development. AISI 1025 samples suitable for tool and die applications in Fused Deposition Modelling (FDM) filament production, were fabricated using Laser Engineered Net Shaping (LENS) process, followed by heat treatment where annealing and quenching processes were done. The material’s microstructure, residual stress and hardness of heat-treated samples under investigation, were compared against the as-built samples. The results indicated that after annealing, tensile residual stresses were reduced by 93%, resulting in a reduced crack growth rate, compared to the as-built sample, although the hardness was reduced significantly by 25%. On the other hand, high tensile residual stresses of 425 ± 14 MPa were recorded after quenching process with an improvement of hardness by 21%.
文摘Predicting the material stability is essential for accelerating the discovery of advanced materials in renewable energy, aerospace, and catalysis. Traditional approaches, such as Density Functional Theory (DFT), are accurate but computationally expensive and unsuitable for high-throughput screening. This study introduces a machine learning (ML) framework trained on high-dimensional data from the Open Quantum Materials Database (OQMD) to predict formation energy, a key stability metric. Among the evaluated models, deep learning outperformed Gradient Boosting Machines and Random Forest, achieving up to 0.88 R2 prediction accuracy. Feature importance analysis identified thermodynamic, electronic, and structural properties as the primary drivers of stability, offering interpretable insights into material behavior. Compared to DFT, the proposed ML framework significantly reduces computational costs, enabling the rapid screening of thousands of compounds. These results highlight ML’s transformative potential in materials discovery, with direct applications in energy storage, semiconductors, and catalysis.
文摘This study presents a novel method to evaluate the safety of open-pit slopes by means of three-dimensional numerical modeling with the finite difference method. The method presented here uses a block model as a vehicle to carry relevant information from the rock mass and automatically construct the numerical model. The results suggest that the method is promising because of its capacity to accurately incorporate a large amount of high-complexity rock data by considering spatial location and material behavior. It is expected that the innovations in this method will make the design, construction, and operation of open-pit iron mines safer and more economical.
文摘This study develops an analytical model to evaluate the cooling performance of a porous terracotta tubular direct evaporative heat and mass exchanger. By combining energy and mass balance equations with heat and mass transfer coefficients and air psychrometric correlations, the model provides insights into the impact of design and operational parameters on the exchanger cooling performance. Validated against an established numerical model, it accurately simulates cooling behavior with a Root Mean Square Deviation of 0.43 - 1.18˚C under varying inlet air conditions. The results show that tube geometry, including equivalent diameter, flatness ratio, and length significantly influences cooling outcomes. Smaller diameters enhance wet-bulb effectiveness but reduce cooling capacity, while increased flatness and length improve both. For example, extending the flatness ratio of a 15 mm diameter, 0.6 m long tube from 1 (circular) to 4 raises the exchange surface area from 0.028 to 0.037 m2, increasing wet-bulb effectiveness from 60% to 71%. Recommended diameters range from 5 mm for tubes under 0.5 m to 1 cm for tubes 0.5 to 1 m in length. Optimal air velocities depend on tube length: 1 m/s for tubes under 0.8 m, 1.5 m/s for lengths of 0.8 to 1.2 m, and up to 2 m/s for longer tubes. This model offers a practical alternative to complex numerical and CFD methods, with potential applications in cooling tower optimization for thermal and nuclear power plants and geothermal heat exchangers.
基金funded by the Project of the Hubei Provincial Department of Science and Technology(Grant No.2022CFB957)the Project of Hubei Engineering University of Teaching Research(Grant No.JY2024032)+1 种基金Ministry of Education University-Industry Cooperation Collaborative Education Project(Grant No.220903584161245)College Students’Innovation and Entrepreneurship Training Program(Grant Nos.DC2024031,DC2024032).
文摘The behavior of single-phase flow and conjugate heat transfer in micro-channel heat sinks(MCHS)subjected to auniform heat flux is investigated by means of numerical simulations.Various geometrical configurations areexamined,particularly,the combinations of rectangular solid and perforated blocks,used to create a disturbancein the flow.The analysis focuses on several key aspects and related metrics,including the temperature distribution,the mean Fanning friction factor,the pressure drop,the Nusselt number,and the overall heat transfer coefficientacross a range of Reynolds numbers(80–870).It is shown that the introduction of such blocks significantlyenhances the heat transfer performances of the MCHS compared to the straight-through flow channel.Specifically,a case is found where the Nusselt number increases by 2.3 times relative to the reference case.The integrationof perforated blocks facilitates the generation of vorticity within the channel,promoting the mixing of coldand hot fluids.Notably,MCHS incorporating perforated rectangular blocks exhibit more pronounced heat transferbenefits at Reynolds numbers smaller than 400.
文摘BACKGROUND Pain in the back or pelvis or fear of back pain may affect the timing or cocontraction of the core muscles.In both static and dynamic movements,the Sahrmann core stability test provides an assessment of core muscle activation and a person's ability to stabilize the lumbopelvic complex.Preparatory cues and images can be used to increase the activation of these muscles.To attain optimal movement patterns,it will be necessary to determine what cueing will give the most effective results for core stability.AIM To investigate the effects of external and internal cues on core muscle activation during the Sahrmann five-level core stability test.METHODS Total 68 participants(21.83±3.47 years)were randomly allocated to an external(n=35)or internal cue group(n=33).Participants performed the Sahrmann fivelevel core stability test without a cue as baseline and the five-level stability exercises with an internal or external cue.External cue group received a pressure biofeedback unit(PBU),and the internal cue group received an audio cue.A Delsys Trigno^(TM)surface electromyography unit was used for muscle activation from the rectus abdominis,external oblique,and transverse abdominis/internal oblique muscles.RESULTS Linear mixed effects model analysis showed that cueing had a significant effect on core muscle activation(P=0.001);however,there was no significant difference between cue types(internal or external)(P=0.130).CONCLUSION Both external and internal cueing have significant effects on core muscle activation during the Sahrmann five-level core stability test and the PBU does not create higher muscle activation than internal cueing.
基金supported by grants from the National Natural Science Foundation of China(Grant No.32072571)the 111 Project(Grant No.B17043)the Construction of Beijing Science,and Technology Innovation and Service Capacity in Top Subjects(Grant No.CEFF-PXM2019_014207_000032)。
文摘Tomato(Solanum lycopersicum)is an important fruit and vegetable crop in worldwide.The fertility of tomato reproductive organs can be dramatically decreased when ambient temperatures rise above 35°C,reducing tomato fruit yield.It is necessary to identify transcription factors(TFs)and target genes involved in heat stress response(HSR)signaling cascades in tomato flower buds to improve tomato plant thermotolerance.In this study,we profiled genes expressed in three developmental stages of tomato flower buds.Red and turquoise modules for heat stress(HS)were identified through gene co-expression network analysis,and the genes within these modules were enriched in HS-related pathways.By focusing on the TFs in the two modules,we identified several novel HSR-related TFs,including SlWRKY75,SlMYB117,and SlNAM.Furthermore,homology analysis illustrated a conserved signaling cascade in tomato.Lastly,we identified and experimentally validated four HSF-regulated genes,namely SlGrpE,SlERDJ3A,SlTIL,and SlPOM1,that likely modulate thermotolerance in plants.These results provide a high-resolution atlas of gene expression during tomato flower bud development under HS conditions,which is a valuable resource for uncovering potential regulatory networks associated with the HSR in tomato.
基金Agricultural Research Development Agency in Thailand for financing the study and the provision of this research.
文摘Extremely high temperatures resulting from climate change have become a major challenge for increasing rice production.Therefore,our objective was to develop heat-tolerant aromatic rice varieties using the pedigree method,focusing on selecting for seed-setting ability under extremely high temperatures along with the use of single nucleotide polymorphism/insertion and deletion(SNP/InDel)markers to improve aromatic properties and grain quality.Furthermore,the QTL-seq approach was utilized to identify QTLs for seed-setting rate in an F2 population subjected to heat stress.The candidate QTL regions were then aligned to confirm SNPs/InDels in synonymous F7 candidate heat-tolerant lines.The results revealed that four promising lines,namely 84-7-1-9,84-7-1-10,159-3-3-1,and 159-3-3-10,were classified as heat-tolerant with low amylose content.In addition,lines 84-7-1-9 and 84-7-1-10 were identified as aromatic rice encompassing the aroma gene(badh2).Regarding the QTL-seq results,the qSF2.1 region ranged from 311051 to 3929422 bp on chromosome 2,was identified based on the highest contrasting SNP index between the heat-susceptible and tolerant bulks.The candidate genes within this region include two genes related to heat shock proteins,three genes associated with pollen fertility,and four genes involved in heat stress and other abiotic stress responses.These genes are proposed as potential candidates for heat tolerance and could serve as targets in rice breeding programs aimed at enhancing heat tolerance.
基金financial support provided by the Research and Application Demonstration of Native Ecological Grass Seed Breeding Technology in“Black Soil Beaches”(2024-SF-101)。
文摘Plant diversity plays a crucial role in maintaining the stability of ecological function.Based on field investigations and experimental analyses,artificial grassland plots with varying sowing times,adjacent natural grassland(CK),and open-pit coal mine dumps in the Muli mining area of Qinghai Province were selected as research subjects for this study.The characteristics of plant diversity and community stability were measured and analyzed,and the relationships between these factors and their influencing variables were evaluated.The results indicated significant differences in the vegetation community characteristics and plant diversity among the various grasslands.Coverage,aboveground biomass,belowground biomass,soil total nitrogen,and soil total carbon were the highest when the growth period was three years.Plant diversity and community stability in the natural grassland were significantly greater than that in the artificial grassland and open-pit coal mine dumps.A significant positive correlation was observed between plant diversity and community stability,suggesting that plant diversity can serve as an index of community stability.The order of stability,from highest to lowest,was CK>11a>10a>8a>9a>6a>7a>3a>2a>1a>0a.Years were identified as the primary factors affecting plant diversity and community stability by altering the soil pH.These results elucidate the relationships and driving mechanisms between plant diversity and community stability in grasslands,providing a scientific basis for maintaining community stability in artificial grassland ecosystems in alpine mining areas.
基金supported by the National Natural Science Foundation of China(32171945,32301760)the Program for Innovative Research Team(in Science and Technology)in University of Henan Province,China(22IRTSTHN023)+2 种基金the Scientific and Technological Research Project of Henan Province,China(242102111116)the National Science Foundation for Postdoctoral Scientists of China(2023M731003)the Postdoctoral Research Subsidize Fund of Henan Province,China(HN2022139)。
文摘Global warming impacts plant growth and development,which in turn threatens food security.Plants can clearly respond to warm-temperature(such as by thermomorphogenesis)and high-temperature stresses.At the molecular level,many small molecules play crucial roles in balancing growth and defense,and stable high yields can be achieved by fine-tuning the responses to external stimuli.Therefore,it is essential to understand the molecular mechanisms underlying plant growth in response to heat stress and how plants can adjust their biological processes to survive heat stress conditions.In this review,we summarize the heat-responsive genetic networks in plants and crop plants based on recent studies.We focus on how plants sense the elevated temperatures and initiate the cellular and metabolic responses that allow them to adapt to the adverse growing conditions.We also describe the trade-off between plant growth and responses to heat stress.Specifically,we address the regulatory network of plant responses to heat stress,which will facilitate the discovery of novel thermotolerance genes and provide new opportunities for agricultural applications.
基金Funded by the Key Industry Innovation Chain(Group)Project of Shaanxi Province,China(No.2019ZDLGY 04-04)the Project of Yulin Science and Technology Bureau(No.2023-CXY-197)。
文摘Fe(Al,Ta)/Fe_(2)Ta(Al)eutectic composites with solidification rates of 6,20,30,and 80μm/s were prepared by a modified Bridgman directional solidification technology.The coarse Fe_(2)Ta(Al)Laves phase was precipitated at the eutectic colony boundary during the solidification process,which can affect the stability of microstructure and properties of the composites.The coarse Laves phase was refined using different heat treatment processes in the present paper.The influences of different heat treatment parameters on the Laves phase content,lamella/rod spacing,and mechanical properties were investigated in detail.In addition,the corrosion behaviors of Fe(Al,Ta)/Fe_(2)Ta(Al)eutectic composites before and after being annealed heat treatment in a 3 g/L Na_(2)S_(2)O_(3)solution were also studied.It is shown that both the content of Laves phase and lamella/rod spacing are gradually decreased after heat treatment.Micro-hardness is decreased,while the yield strength,compressive strength,and corrosion resistance are improved.The optimum heat treatment process is selected as well.
文摘In this paper,we establish a stability estimate for the isoperimetric inequality of horospherically convex domains in hyperbolic plane.This estimate involves a relationship between the Hausdorff distance to a geodesic ball and the deficit in the isoperimetric inequality,where the coefficient of the deficit is a universal constant.
基金supported by the National Key R&D Program of China (No. 2022YFE0204100)the National Natural Science Foundation of China (12205067 and 12375199)the Fundamental Research Funds for the Central Universities (Grant No. HIT.OCEF. 2022036)。
文摘This paper establishes an amplitude modulation heating model, simulating the far-field radiation of ELF/VLF signals generated by modulation heating, as well as the specific location and longitudinal extent of the radiation source. We consider various modulation waveforms and find that square-wave modulation has the highest excitation efficiency for ELF/VLF signals, and that square-wave modulation with a smaller duty cycle(<50%) exhibits higher excitation efficiency for ELF/VLF signals, while the sin^(2)t waveform modulation yields the lowest proportion of harmonic energy in the generated signals. The amplitude of the second harmonic generated by the sin^(2)t waveform is less than one-tenth that of the fundamental frequency, and the energy of higher-frequency harmonics can be negligibly small compared with those of the fundamental wave. It is a challenging task to achieve a balance between enhancing the excitation efficiency of ELF/VLF signals and also suppressing harmonics generated by the modulated heating process. This is because the harmonics are correspondingly enhanced as the excitation efficiency of the signals is increased. However, we find that under conditions of varying effective radiant power and modulation frequency, as long as the modulation waveform is unchanged, the energy ratio between the fundamental frequency signal generated by modulated heating and each harmonic is relatively fixed, with changes only in signal intensity and the location of the radiation source zone. This implies that one can first select modulation waveforms that make the signal less prone to distortion, then increase the effective radiated power to enhance the signal strength, without concern for harmonic interference of the fundamental signal.
基金supported by Beijing Joint Research Program for Germplasm Innovation and New Variety Breeding(Grant No.G20220628003-03)Chongqing Municipal People's Government and Chinese Academy of Agricultural Sciences strategic cooperation project,Key-Area Research and Development Program of Guangdong Province(Grant No.2020B020220001)+3 种基金the Earmarked Fund for Modern Agro-industry Technology Research System(Grant No.CARS-23)Science and Technology Innovation Program of the Chinese Academy of Agricultural Science(Grant No.CAAS-ASTIP-IVFCAAS)Central public-interest Scientific Institution Basal Research Fund(Grant No.Y2017PT52)the Key Laboratory of Biology and Genetic Improvement of Horticultural Crops,Ministry of Agriculture,P.R.China。
文摘Heat stress causes overgrowth,leaf dryness and fruit malformation,which negatively impacts cucumber quality and yield.Yet,in spite of the devastating consequences of this abiotic stress,few genes for heat tolerance in cucumber have been identified.Here,the heat injury indices of 88 cucumber accessions representing diverse ecotypes were collected in two open-field environments,with naturally occurring high temperatures over two years.Seventeen of the 88 accessions were identified as highly heat-tolerant.Using a genome-wide association study,five loci(gHII3.1,gHII3.2,gHII3.3,gHII4.1 and gHII6.1)on three chromosomes associated with heat tolerance were detected.Pairwise linkage disequilibrium correlation,sequence polymorphisms,and qRT-PCR analyses at these loci,identified five candidate genes predicted to be casual for heat stress response in cucumber.CsaV3_3G04883,CsaV3_4G029050 and CsaV3_6G005370 each had nonsynonymous SNPs,and were significantly up-regulated by heat stress in the heat-tolerant genotypes.CsaV3_3G031890 was also induced by heat stress,but in the heatsensitive genotypes,and sequence polymorphism was only found in the promoter region.Identifying these candidate genes lays a foundation for understanding cucumber thermotolerance mechanisms.Our study is one of the few to examine heat stress in adult cucumber plants and it therefore fills a critical gap in knowledge.It is also an important first-step towards accelerating the breeding of robust heat-tolerant varieties.
基金the funding support from the National Natural Science Foundation of China(Grant Nos.52304101 and 52004206)the China Postdoctoral Science Foundation(Grant No.2023MD734215)。
文摘Backfill is often employed in mining operations for ground support,with its positive impact on ground stability acknowledged in many underground mines.However,existing studies have predominantly focused only on the stress development within the backfill material,leaving the influence of stope backfilling on stress distribution in surrounding rock mass and ground stability largely unexplored.Therefore,this paper presents numerical models in FLAC3D to investigate,for the first time,the time-dependent stress redistribution around a vertical backfilled stope and its implications on ground stability,considering the creep of surrounding rock mass.Using the Soft Soil constitutive model,the compressibility of backfill under large pressure was captured.It is found that the creep deformation of rock mass exercises compression on backfill and results in a less void ratio and increased modulus for fill material.The compacted backfill conversely influenced the stress distribution and ground stability of rock mass which was a combined effect of wall creep and compressibility of backfill.With the increase of time or/and creep deformation,the minimum principal stress in the rocks surrounding the backfilled stope increased towards the pre-mining stress state,while the deviatoric stress reduces leading to an increased factor of safety and improved ground stability.This improvement effect of backfill on ground stability increased with the increase of mine depth and stope height,while it is also more pronounced for the narrow stope,the backfill with a smaller compression index,and the soft rocks with a smaller viscosity coefficient.Furthermore,the results emphasize the importance of minimizing empty time and backfilling extracted stope as soon as possible for ground control.Reduction of filling gap height enhances the local stability around the roof of stope.
