Search Results (236)

Stable rice production is critical for ensuring national food security and agricultural sustainability. Climate change is increasing the demand for efficient crop management strategies to maintain rice production. Foliar fertilization enables rapid nutrient supplementation by directly delivering nutrients to aboveground tissues while avoiding soil-related limitations. However, most foliar formulations are primarily designed for rapid nutrient delivery and have limited capacity to prolong water retention and nutrient availability on leaf surfaces after application. Hydrogels possess excellent water-retention and nutrient-delivery capabilities, but their intrinsic crosslinked networks limit water solubility and foliar suitability. Inspired by these characteristics, a sprayable polymer-based formulation was designed to combine hydrogel-like moisture preservation with foliar application compatibility. In this study, a foliar moisture-preserving synergist (FMPS) was developed using radiation-synthesized potassium polyacrylate as the polymer matrix, with urea and glucose incorporated as nitrogen and carbon sources, respectively. Structural characterization revealed morphological changes after incorporation of urea and glucose into PAA-K, while Fourier transform infrared spectroscopy suggested their incorporation and possible intermolecular interactions. Under standard growth conditions, FMPS increased the effective panicle number, filled grain number, and seed-setting rate by 29.3%, 18.4%, and 4.0%, respectively, resulting in significantly improved rice yield. These findings demonstrate the potential of FMPS as a hydrogel-inspired foliar formulation for enhancing rice productivity. Full article

Improving rice yield and optimizing rice quality are of great significance for ensuring food security. In modern rice production, mechanical transplanting has become the dominant transplanting method. Precise regulation of plant spacing and row spacing contributes to the formation of different transplanting densities, which further exerts effects on photosynthetic spikelets filling, yield formation and quality development of rice. Two-year field experiments were conducted with two conventional japonica rice cultivars of contrasting yield levels under four transplanting hill spacings at a uniform row spacing of 30 cm. The results showed that rice cultivars with higher seed-setting rate with an increase ranging from 1.44 to 1.91% and larger grain weight with an increase ranging from 13.17 to 13.40% presented more prominent yield potential. In addition, high-yield rice cultivars possessed more excellent photosynthetic carbon metabolism characteristics, which effectively improved the spikelets filling process of rice kernels. Superior photosynthetic carbon metabolism characteristics were conducive to increasing head rice rate and reducing chalkiness, while maintaining the duration of spikelets filling benefited the improvement of rice taste value. Narrowing the transplanting plant spacing reduced the physiological enzyme activities in rice leaves and grains, weakened photosynthetic carbon metabolism and hindered spikelets filling, which further decreased head rice rate and protein content but increased chalkiness. Notably, rice taste value also showed an increasing trend. The taste value of superior spikelets (SSs) of the two rice cultivars increased by 1.97–5.11% and 0.98–2.60% respectively, and that of inferior spikelets (ISs) increased by 1.37–3.64% and 1.62–4.12% respectively. Reducing transplanting plant spacing also significantly increased the number of effective panicles, resulting in an increase in population spikelet number. The final yield of the two rice cultivars increased by 5.38–11.62% and 5.23–11.03% respectively. Full article

Wheat production demands simplified fertilization strategies to achieve sustainable high yields. This study evaluated the effects of the one-time high-rate application of an organic–inorganic compound fertilizer on soil properties, photosynthetic characteristics, and grain yields. A multi-year field experiment was conducted with a single basal application of an organic–inorganic compound fertilizer at 3600 kg·ha⁻¹, using conventional split chemical fertilization as the control. Compared with the control, this treatment significantly increased soil organic matter and available nutrient content, enhanced the bacteria/fungi ratio, elevated soil enzyme activity, and promoted the conversion of humus into more stable forms. These improvements sustained a higher flag leaf photosynthetic capacity during the grain-filling stage and delayed leaf senescence. The multi-year average grain yield was 5.28% higher than that of conventional split fertilization. The one-time high-rate application of an organic–inorganic compound fertilizer can improve soil biological properties, maintain late-season photosynthetic function, and increase yields, serving as an effective technical measure for simplified, sustainable, and high-yield wheat cultivation in the region. Full article

Optimizing rice (Oryza sativa L.) plant architectype is an important approach to coordinating the source–sink relationship and unlocking yield potential. In this study, using the large-panicle rolled-leaf variety ST-12 and the small-panicle flat-leaf variety Nipponbare, we systematically compared plant architectype traits, photosynthetic characteristics, biomass accumulation, carbohydrate accumulation and remobilization, source–sink characteristics, and yield under two nitrogen levels in field conditions to test the hypothesis that excessive leaf rolling influences the accumulation and translocation of photosynthetic products and disrupts the source–sink balance. The results showed that Nipponbare exhibited significantly higher yield than ST-12 under both nitrogen levels, attributable to its higher number of productive panicles, grain-filling percentage, and thousand-grain weight. Although ST-12 had a higher single-leaf photosynthetic rate and leaf area index, its top three leaves were excessively rolled, reducing its canopy light interception and canopy photosynthetic rate, thereby leading to significantly lower stem NSC content at heading and biomass accumulation during grain filling compared with Nipponbare. Notably, ST-12 had higher contents of cellulose, hemicellulose, and lignin in the stem at heading, directing more pre-anthesis photosynthetic products into structural carbon, while the translocation of non-structural carbohydrates to grains was not affected. Further analysis revealed that ST-12 had a lower source capacity, sugar–spikelet ratio, source–spikelet ratio, and source–sink ratio than Nipponbare, whereas its total spikelet number and sink capacity were significantly higher. Correlation analysis showed that source characteristic indices and the source–sink ratio were positively correlated with yield, grain-filling percentage, and thousand-grain weight, while sink characteristic indices were negatively correlated with these traits. In conclusion, excessive leaf rolling impairs canopy photosynthesis, leading to a large sink but weak source imbalance. For large-panicle varieties, a higher source–sink ratio, not simply larger sink size or total biomass, is the key to high yield. Full article

Early-season rice in the middle and lower reaches of the Yangtze River is vital for China’s food security, but the planting area has sharply decreased in recent years due to its poor appearance and taste quality, as well as low returns. Therefore, we collected and analyzed 334 early-season rice varieties released in the region from 2000 to 2022. To verify whether low-amylose content (L-Am) varieties can reduce chalkiness without compromising yield, two field experiments were conducted: a two-year consecutive experiment (2021–2022) using six representative varieties (low amylose, L-Am: 14.5–16.8%; medium-high amylose, MH-Am: 23.8–25.9%), and a one-year validation experiment (2024) utilizing 32 widely cultivated varieties. The results indicated that the amylose content (AC) of the 334 varieties showed a normal distribution, with varieties containing 18–20% AC being the most prevalent (23.6%), which resulted in L-Am varieties collectively accounting for 46.4%; additionally, AC was significantly positively correlated with chalky kernel rate (CKR) and chalkiness degree (CKD), and negatively correlated with panicles per m² and length–width ratio (LWR), but showed no correlation with yield. Similarly, L-Am and MH-Am varieties achieved comparable yields through compensatory adjustments in field experiments: L-Am varieties had 12.8–13.9% more panicles per m² but 3.6–7.3% lower 1000-grain weight. Moreover, L-Am varieties exhibited superior grain quality, with 70.8–73.5% and 54.0–62.1% lower CKR and CKD, respectively. Physiological analyses revealed that L-Am varieties exhibited a smaller maximum grain-filling rate (GFR_max) and amylose accumulation rate (GAmR_max), mean grain-filling rate (GFR_mean) and amylose accumulation rate (GAmR_mean), longer active grain-filling/amylose accumulation periods (D), and higher activities of soluble starch synthase (SSS) during grain-filling stages. These results demonstrate that early-season rice varieties with low AC tend to exhibit significantly lower chalkiness. Physiologically, this superior appearance quality is strongly associated with maintained yield through compensatory yield components and distinct starch synthesis kinetics, offering a practical strategy for enhancing both quality and productivity in early-season rice. Full article

This study examines the microstructural characteristics and tensile properties of autogenous orbital gas tungsten arc (GTA) circumferential butt welds produced on commercially rolled 304 stainless steel seam pipes (outer diameter 38.1 mm, wall thickness 2.0 mm) for high-purity fluid distribution systems. A three-segment current profile was employed using an AMI 8-4000 orbital system, with peak currents of 70, 67, and 65 A for the penetration, remelting, and downslope (crater-fill) segments, respectively, under high-purity Ar (99.999%) shielding with back purging. Electron backscatter diffraction (EBSD) analysis, including image quality (IQ), inverse pole figure (IPF), and kernel average misorientation (KAM) mapping, showed that the weld metal consists of epitaxially grown columnar austenite grains strongly oriented along the solidification direction, whereas the heat-affected zone (HAZ) exhibits finer equiaxed grains with an increased Σ3 twin boundary fraction and elevated low-angle boundary fraction, indicative of partial recrystallization. Only sparse, discontinuous δ-ferrite stringers were detected in the fusion zone, and no non-metallic inclusions were observed on fracture surfaces, supporting the weld metal’s suitability for semiconductor-grade cleanliness. Vickers microhardness profiles revealed modest hardness differences (typically within 10–20 HV) between the weld metal, HAZ, and base metal, with no pronounced HAZ softening. Cross-weld tensile tests conducted in accordance with ASTM E8/E8M-22 yielded yield strengths above 200 MPa, ultimate tensile strengths of 650–680 MPa, and total elongations approaching 40%, comparable to the as-received pipe. Scanning electron fractography confirmed fully ductile failure via microvoid coalescence without evidence of cleavage, intergranular decohesion, or weld-defect-induced embrittlement. Collectively, these results demonstrate that the three-segment autogenous orbital GTAW procedure produces structurally sound, particle-clean joints suitable for 304 stainless steel seam pipes used in high-purity industrial piping. Full article

To investigate the effects of planting density and chemical regulation measures, as well as their interactions, on the plant morphological characteristics, stem mechanical properties, leaf anatomical structure, dry matter accumulation and allocation, and yield and its components of grain maize in the Hexi Oasis irrigation area, a field experiment was conducted from 2024 to 2025. Planting density was set as the main factor, with five density levels: 82,500 plants·ha⁻¹ (M1), 97,500 plants·ha⁻¹ (M2), 112,500 plants·ha⁻¹ (M3), 127,500 plants·ha⁻¹ (M4) and 142,500 plants·ha⁻¹ (M5). Chemical regulation measures were set as the secondary factor, consisting of two treatments: spraying 30% aminoethyl hexanoate·ethephon at the 10-leaf stage (T1) and spraying an equal amount of water as the control (T2). The results revealed that, as planting density increases, the maize plant height, ear height and stem breakage rate rise continuously, whilst stem diameter, stem breaking resistance, rind puncture strength, leaf thickness and epidermal tissue thickness showed a downward trend. The leaf area index, ear length, kernel number per ear, kernel weight and yield all exhibited a trend of first increasing and then decreasing, reaching their peak at the M3 planting density. Compared with conventional planting patterns, spraying chemical regulators significantly reduced plant height by 10.66~13.99% and ear height by 16.12~19.57%, increased stem diameter by 2.12~13.79%, and enhanced stem breaking resistance by 7.71~23.11% and rind puncture strength by 5.17~12.65% at 30 days after silking. Additionally, it delayed leaf senescence, increased the leaf area index by 4.37~10.03% during the filling stage, and increased yield by 1.99~4.06%. The synergistic effect of moderately increasing planting density combined with chemical regulation can effectively coordinate the ‘population–individual’ contradiction in maize, reduce plant height and ear height and increase stem diameter and rind puncture strength, while maintaining a higher leaf area index after the silking stage and promoting dry matter translocation to grains, thereby achieving a synergy between lodging resistance and high yield. Among them, a planting density of 112,500 plants·ha⁻¹ combined with spraying chemical regulators yielded the highest maize yield and harvest index, reaching 20.28~20.48 t·ha⁻¹ and 0.52~0.53, respectively. Compared with other treatments, the increases ranged from 2.54~47.51% for yield and from 1.92~36.84% for the harvest index. Meanwhile, this treatment exhibited superior stem mechanical properties and a lower stem breakage rate. Taking into account factors such as lodging resistance, yield, dry matter accumulation and allocation, it has been determined that a planting density of 112,500 plants·ha⁻¹ combined with spraying 30% aminoethyl hexanoate·ethephon at the 10-leaf stage is an effective strategy for achieving both lodging resistance and high yield in grain maize in the Hexi Oasis irrigation area. Full article

To mitigate welding defects in copper wire conductors induced by their high laser reflectivity and thermal conductivity during laser welding, this study combines numerical simulation and experimental testing to investigate the influences of laser processing parameters on the mechanical properties, molten pool dynamic evolution, and microstructural characteristics of copper self-fusion welds and pure Ni powder-filled welds. The results demonstrate that, for self-fusion welding, a moderate increase in laser power and welding time elevates the heat input, which promotes weld penetration and forming quality. The optimal parameter combination (3900 W, 1.0 s) yields a balanced internal densification and grain refinement, with the joint tensile strength reaching a peak of 245 MPa. For Ni powder-filled welding, the infinite solid solubility between Cu and Ni improves interfacial metallurgical bonding. Under the optimal parameters (3500 W, 1.2 s), the joint tensile strength increases to 282 MPa. Heat input exerts a significant effect on the temperature field evolution in both welding processes, yet the molten pool expansion behaviors differ: self-fusion welding exhibits continuous expansion with rising heat input, whereas Ni powder-filled welding displays complex nonlinear variations. Full article

This study addresses the critical issues of rigid energy use and insufficient demand-side responsiveness in office buildings’ Variable Refrigerant Flow (VRF) systems under complex summer conditions. Existing research lacks fine-grained characterisation of short-term load fluctuations and often fails to accurately couple energy efficiency with humidity-adapted thermal comfort. To fill this gap, this paper proposes an integrated Model Predictive Control (MPC) framework driven by load characteristic identification and a novel hybrid prediction model. First, based on actual hourly metered data (683,280 records), K-means clustering was employed to identify three typical load patterns, pinpointing short-term peak loads in core office zones as the primary target for flexible regulation. Second, a high-precision GS-DBO-ELM prediction model—integrating Grid Search and Dung Beetle Optimisation—was developed to capture the nonlinear dynamics of VRF energy consumption and Predicted Mean Vote (PMV). The model achieved an R² of 0.99 with relative errors constrained within ±5%. Finally, a multi-objective MPC strategy, solved via an improved Artificial Hummingbird Algorithm (HAGSAHA) and weighted by the Analytic Hierarchy Process (AHP), was implemented to dynamically adjust zone-level temperature setpoints. Results demonstrate that the proposed MPC strategy reduces daily cooling energy consumption by 7.95–10.69% and peak loads by 15.3%, while maintaining strict thermal comfort (PMV within ±0.5). Under a time-of-use pricing mechanism, the flexible scheduling strategy achieved a 12.37% total electricity reduction and a 9.54% reduction in operating costs. This work provides a highly replicable, climate-tailored solution for low-carbon, flexible energy management in public buildings. Full article

To enhance the engineering performance of fine-grained composite soils with unbalanced particle gradation, high plasticity, and poor water stability, a synergistic stabilization strategy combining particle structure regulation and microbially induced calcium carbonate precipitation (MICP) was proposed. The particle size distribution and fundamental engineering properties of a titanium gypsum–clay (TSC) composite soil were first optimized through systematic single-factor blending tests. The results indicate that a TS:C ratio of 60:40 significantly improved gradation characteristics, reduced plasticity, and enhanced both compaction behavior and load-bearing capacity. Based on the optimized gradation framework, MICP treatment was subsequently introduced to further enhance water stability. The effects of key parameters, particularly the type of calcium source, on the evolution of water stability were systematically investigated. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to elucidate the underlying reinforcement mechanisms. The results demonstrate that the water stability coefficient increased markedly from 0.35 to 0.83 following MICP treatment, while strength degradation under water immersion was effectively mitigated. Microscopic observations reveal that microbially precipitated calcite fills pore spaces and forms a continuous cementation network via particle bridging and interfacial bonding, leading to an approximately 32% reduction in porosity. Overall, the proposed synergistic strategy offers an effective and sustainable approach for improving the water stability and structural integrity of complex fine-grained composite soils. Full article

A large number of low-resistivity and low-permeability reservoirs have been discovered in the deep Paleogene strata of the Wenchang Sag. These reservoirs are characterized by complex porosity–permeability relationships and difficulties in fluid property identification, which restrict the progress of exploration and development operations. However, existing reservoir studies mostly focus on either low-permeability or low-resistivity reservoirs, with relatively few investigations targeting this specific type. Using petrological analysis and physical property testing as the main methods, combined with sedimentary and diagenetic studies, this paper examines the characteristics and genesis of low-resistivity and low-permeability reservoirs in the Paleogene of the Wenchang Sag. The results show that the Paleogene reservoirs are dominated by lithic quartz sandstones, with secondary pores as the main reservoir space, consisting of medium–small pores and fine throats. Samples of the same grain size exhibit a favorable porosity–permeability correlation. Based on capillary pressure curve morphology, the reservoirs can be classified into three types: high mercury intrusion saturation with low displacement pressure, medium mercury intrusion saturation with medium displacement pressure, and medium mercury intrusion saturation with medium–high displacement pressure. The low porosity and permeability are mainly attributed to the fact that the reservoir rocks are primarily deposited in near-source braided fluvial delta underwater distributary channels, resulting in low compositional and textural maturity of sandstones. Strong compaction resistance leads to a significant reduction in primary pores during burial, and intergranular cement filling further deteriorates physical properties. On the other hand, rapid lithological changes and complex pore structures give rise to abundant isolated pores and poor connectivity, leading to high irreducible water saturation. Coupled with high formation water salinity, these factors collectively give rise to low-resistivity reservoirs in the study area. This study clarifies the formation mechanism of low-permeability and low-resistivity reservoirs in the Paleogene of the Wenchang Sag, providing guidance for reservoir evaluation in subsequent oil and gas exploration and serving as a reference for analogous areas. Full article

Highland hulless barley is a core grain crop on the Qinghai–Tibet Plateau. Limited research on hybrid vigour and combining ability has constrained hybrid breeding progress. This study employed eight Himalayan barley varieties as parents and utilized the NCII design to generate 16 hybrid combinations. Hybrid vigour, combining ability, and genetic parameters were analyzed for 11 core ear and grain agronomic traits. Results indicated significant hybrid vigour across all traits: combination 1789 × 84 showed the highest total ear weight (midparent advantage: 116.74%, super-parent advantage 104.60%) and grain weight per ear (mid-parent advantage 126.78%, super-parent advantage 120.13%) in combination 1789 × 84, while thousand-grain weight showed the strongest hybrid vigour in combination 74 × 84 (mid-parent advantage 41.64%). Complementarity ability analysis revealed that parent 69 exhibited extremely significant positive general combining ability (GCA) effects across multiple core traits, making it the optimal parent for comprehensive traits; combination 1791 × 69 demonstrated the highest specific combining ability (SCA) effects. Genetic parameters indicated that traits such as the number of filled grains and total ear weight were primarily influenced by additive effects, as indicated by the higher GCA variance components compared with SCA variance components for these traits. Furthermore, thousand-grain weight was identified as a key integrative trait linking spike and grain characteristics, and its improvement can simultaneously enhance multiple yield-related traits. The superior parents (69, 1789, 1791) and strong-advantage combinations identified in this study provide a scientific basis for parent selection, combination screening, and breeding strategy formulation in high-yielding hybrid breeding of barley. Full article

Low temperature during grain filling is a major constraint affecting rice quality in cold regions. This study investigated how low temperature influences rice quality and starch characteristics at different periods of the grain-filling stage using two Japonica rice cultivars, Kenjing 7 (KJ7, moderate stress tolerance) and Kenjing 8 (KJ8, strong stress tolerance). Low-temperature treatments (17/13 °C, day/night) were applied during the early (5–11 days after anthesis), middle (12–18 days), and late (19–25 days) grain-filling stages and milling, appearance, nutritional, eating and cooking qualities as well as starch physicochemical properties were evaluated. Responses differed markedly between cultivars and treatment periods. Under low-temperature conditions, brown rice and milled rice rates of KJ8 increased during the early and middle grain-filling stages, whereas those of KJ7 declined during the late stage. Low-temperature stress increased protein, total starch, and amylose contents, while reducing gel consistency and the taste value of KJ7. Grain chalkiness increased significantly during the late stage, whereas during the early and middle stages, grain chalkiness, peak viscosity, and breakdown decreased and setback increased. Low temperature increased starch granule size and the proportions of short and intermediate chains of amylopectin, reduced medium-long and long chain and relative crystallinity, without altering starch crystalline type, and produced uneven starch particle surfaces with small pores. These effects were most pronounced during the late grain-filling stage. Overall, low temperature altered starch content and structure, thereby modifying pasting properties and ultimately leading to differences in rice quality. Full article

Moderate thermal exposure can significantly influence the mechanical behavior of volcanic rocks by inducing microcrack development and altering crack network characteristics. However, quantifying such damage processes remains challenging when relying solely on conventional mechanical parameters. In this study, the evolution of crack network complexity in andesite and andesitic–basaltic rocks subjected to moderate thermal exposure (200 °C) is investigated using fractal analysis integrated with mechanical and mineralogical observations. Six core specimens were tested under uniaxial compression, including three natural specimens and three specimens thermally treated at 200 °C prior to loading. After failure, crack surfaces were digitized and fractal dimensions (D) were calculated using the box-counting method. Petrographic observations and X-ray powder diffraction (XRPD) analyses were conducted to characterize the mineralogical composition and microstructural features controlling crack development. The results indicate that thermal exposure primarily reduces rock stiffness rather than peak strength. While the uniaxial compressive strength (UCS) of two specimens remains nearly unchanged after heating, the elastic modulus (E) decreases in all thermally treated specimens. Mineralogical observations reveal a heterogeneous volcanic fabric dominated by plagioclase and pyroxene within a fine-grained groundmass, with secondary calcite phases occurring in veins and pocket fillings. Fractal analysis shows generally lower D values in thermally treated specimens, suggesting crack redistribution and coalescence rather than increased network complexity, consistent with the observed reduction in stiffness and a tendency toward more ductile deformation behavior. Full article

To investigate the differences in carbon and nitrogen metabolism between superior and inferior grains of southern soft and non-soft japonica rice and their relationships with appearance quality, the metabolic characteristics and appearance quality of superior and inferior grains during the grain-filling stage were compared between the two rice types. The results showed that, compared with non-soft japonica rice, the activities of AGPase and GBSS in superior grains of soft rice were significantly lower, whereas the activities of SSS, SBE, and DBE were significantly higher. The amylose content decreased by 32.68–44.72%, while amylopectin increased by 7.27–10.73%. The limitation in carbon metabolism was more pronounced in inferior grains, and the non-structural carbohydrate content was 9.33–17.33% lower than that in superior grains. In terms of nitrogen metabolism, GS activity decreased whereas GOGAT activity increased in superior grains, resulting in a 6.28–8.38% increase in protein content. The protein content of inferior grains was 1.75–6.44% higher than that of superior grains. In addition, the chalky grain rate and chalkiness degree of superior grains in soft rice were 79.00–481.03% higher than those in non-soft japonica rice, while the increases in inferior grains ranged from 67.51% to 136.31%. Correlation analysis indicated that the chalky grain rate of superior grains was positively correlated with starch content during the early grain-filling stage, whereas the chalkiness degree of inferior grains was positively correlated with protein content. These results suggest that differences in carbon and nitrogen metabolism between grain positions are closely associated with the formation of appearance quality. Full article