分类： 地球科学 >> 地理学 提交时间： 2025-07-17 合作期刊: 《干旱区科学》
JIN Zizhen
QIN Xiang
LI Xiaoying
ZHAO Qiudong
ZHANG Jingtian
MA Xinxin
WANG Chunlin
HE Rui
WANG Renjun
摘要： Understanding the impact of meteorological and topographical factors on snow cover fraction (SCF) is crucial for water resource management in the Qilian Mountains (QLM), China. However, there is still a lack of adequate quantitative analysis of the impact of these factors. This study investigated the spatiotemporal characteristics and trends of SCF in the QLM based on the cloud-removed Moderate Resolution Imaging Spectroradiometer (MODIS) SCF dataset during 2000–2021 and conducted a quantitative analysis of the drivers using a histogram-based gradient boosting regression tree (HGBRT) model. The results indicated that the monthly distribution of SCF exhibited a bimodal pattern. The SCF showed a pattern of higher values in the western regions and lower values in the eastern regions. Overall, the SCF showed a decreasing trend during 2000–2021. The decrease in SCF occurred at higher elevations, while an increase was observed at lower elevations. At the annual scale, the SCF showed a downward trend in the western regions affected by westerly (52.84% of the QLM). However, the opposite trend was observed in the eastern regions affected by monsoon (45.73% of the QLM). The SCF displayed broadly similar spatial patterns in autumn and winter, with a significant decrease in the western regions and a slight increase in the central and eastern regions. The effect of spring SCF on spring surface runoff was more pronounced than that of winter SCF. Furthermore, compared with meteorological factors, a variation of 46.53% in spring surface runoff can be attributed to changes in spring SCF. At the annual scale, temperature and relative humidity were the most important drivers of SCF change. An increase in temperature exceeding 0.04°C/a was observed to result in a decline in SCF, with a maximum decrease of 0.22%/a. An increase in relative humidity of more than 0.02%/a stabilized the rise in SCF (about 0.06%/a). The impacts of slope and aspect were found to be minimal. At the seasonal scale, the primary factors impacting SCF change varied. In spring, precipitation and wind speed emerged as the primary drivers. In autumn, precipitation and temperature were identified as the primary drivers. In winter, relative humidity and precipitation were the most important drivers. In contrast to the other seasons, slope exerted the strongest influence on SCF change in summer. This study facilitates a detailed quantitative description of SCF change in the QLM, enhancing the effectiveness of watershed water resource management and ecological conservation efforts in this region.
分类： 物理学 >> 核物理学 提交时间： 2025-07-09
摘要： Within the framework of the isospin-dependent quantum molecular dynamics model, the fusion cross section and fusion mechanism of neutron-deficient Pu isotopes in the reactions 24,26,30Si+196Hg were investigated. We found that the fusion cross sections are higher in the reaction with a more neutron-rich beam owing to the lower dynamical barrier. The dynamic barrier decreases with decreasing incident energy, which explains the fusion enhancement at the sub-barrier energy. The peak value of N/Z ratio in the neck region was the highest in reaction 30Si+196Hg, indirectly leading to the lowest dynamic barrier. Compared with the proton density distribution, the neck region for neutrons is larger, indicating that neutrons transfer more quickly than protons, leading to a high N/Z ratio in the neck. The time distribution of the appearance of dynamical barriers was wider at lower incident energies, indicating that the fusion process took longer to exchange nucleons. The single-particle potential barrier decreases with time evolution and finally disappears at a lower impact parameter, which is favorable for fusion events.
分类： 管理学 >> 可持续发展管理 提交时间： 2025-07-08
摘要： Green credit policy is an important tool to promote the green and clean development of the industrial sector.，the transformation effect of the industrial sector directly affects the global climate governance process. To explore how green financial policies will impact coordinated carbon pollution emission reduction, this study uses the double difference model (DID) to evaluate the impact of green financial policies on coordinated carbon pollution emission reduction. Constructing an Empirical Analysis of Provincial Panel Data in China from 2008 to 2021. Results show that the green credit policy significantly inhibited the synergistic emission of carbon pollution, with a coefficient of -0.0278, and had a synergistic and significant effect on the total pollutant emissions. The mechanism test shows that the policy drives emission reduction through the path of technological innovation; however, the mechanism of industrial structure adjustment and energy efficiency has not reached a significant level. Furthermore, the policy effect is more significant in areas with high economic levels, areas with low proportions of secondary industry, and areas with high environmental regulation, revealing the heterogeneity of regional economic structure, industrial dependence, and environmental supervision on policy transmission. Based on this, we proposed some recommendations: to strengthen the regional adaptability of green financial instruments, focus on technological innovation incentives, and break heterogeneous bottlenecks through differentiated policy design to improve the efficiency of collaborative governance of carbon pollution and help promote the synergy of global climate goals and sustainable development agendas.
分类： 农、林、牧、渔 >> 土壤学 提交时间： 2025-07-07 合作期刊: 《干旱区科学》
Jyotirmay ROY
Dipak Ranjan BISWAS
Biraj Bandhu BASAK
Ranjan BHATTACHARYYA
Shrila DAS
Sunanda BISWAS
Renu SINGH
Avijit GHOSH
摘要： Understanding how different vegetation-based restoration practices alter soil chemical and microbial characteristics is crucial, as restoration practices influence phosphorus (P) transformation and fractions and modify P adsorption behavior during the restoration process of degraded land. This study investigated the impacts of vegetation-based restoration practices on soil chemical and microbial parameters, P fractions, and patterns of P adsorption and desorption, and highlighted the combined influence on P availability. To evaluate the impact of vegetation-based restoration practices on P fractions and adsorption behavior in the semi-arid degraded land in India, this study compared three distinct tree-based restoration systems, including Leucaena leucocephala (Lam.) de Wit-based silviculture system (SCS), Acacia nilotica (L.) Willd. ex Delile-based silvopasture system (SPS), and Emblica officinalis Gaertn-based hortipasture system (HPS), with a natural grassland system (NGS) and a degraded fallow system (FS) as control. The soil samples across various soil depths (0–15, 15–30, and 30–45 cm) were collected. The findings demonstrated that SCS, SPS, and HPS significantly improved soil organic carbon (SOC) and nutrient availability. Moreover, SCS and SPS resulted in increased microbial biomass phosphorus (MBP) content and phosphatase enzyme activity. The P fractionation analysis revealed that ferrum-associated phosphorus (Fe-P) was the major P fraction, followed by aluminum-associated phosphorus (Al-P), reflecting the dominance of ferrum (Fe) and aluminum (Al) oxides in the semi-arid degraded land. Compared with FS, vegetation-based restoration practices significantly increased various P fractions across soil depths. Additionally, P adsorption and desorption analysis indicated a lower adsorption capacity in tree-based restoration systems than in FS, with FS soils adsorbing higher P quantities in the adsorption phase but releasing less P during the desorption phase. This study revealed that degraded soils responded positively to ecological restoration in terms of P fraction and desorption behavior, influencing the resupply of P in restoration systems. Consequently, litter rich N-fixing tree-based restoration systems (i.e., SCS and SPS) increased total phosphorus (TP) stock for plants and sustained the potential for long-term P supply in semi-arid ecosystems. With the widespread adoption of restoration practices across degraded landscapes, SCS and SPS would significantly contribute to soil restoration and improve productivity by maintaining the soil P supply in semi-arid ecosystems in India.
分类： 地球科学 >> 大气科学 提交时间： 2025-07-07 合作期刊: 《干旱区科学》
摘要： Given that Xinjiang Uygur Autonomous Region of China possesses exceptionally abundant solar radiation resources that can be harnessed to develop clean energy, accurately characterizing their spatiotemporal distribution is crucial. This study investigated the applicability of the Clouds and the Earth’s Radiant Energy System (CERES) Single Scanner Footprint TOA/Surface Fluxes and Clouds (SSF) product downward surface shortwave radiation dataset (DSSRCER) under clear-sky conditions in Xinjiang. By integrating multi-source data and utilizing techniques like multivariate fitting and model simulation, we established a two-layer aerosol model and developed a clear-sky downward surface shortwave radiation (DSSR) retrieval model specific to Xinjiang using the Santa Barbara Discrete Atmospheric Radiative Transfer (SBDART) model. We further explored the spatiotemporal distribution characteristics of DSSR under clear-sky conditions in Xinjiang from 2017 to 2019 based on the localized DSSR retrieval model. Our findings revealed a significant discrepancy in DSSRCER under clear-sky conditions at the Xiaotang station in Xinjiang. By comparing, screening, and correcting core input parameters while incorporating the two-layer aerosol model, we achieved a more accurate SBDART simulated DSSR (DSSRSBD) compared to DSSRCER. The annual mean DSSR exhibited a distinct distribution pattern with high values in mountainous regions such as the Altay Mountains, Kunlun Mountains, and Tianshan Mountains and significantly lower values in adjacent lowland areas, including the Tarim River Basin and Junggar Basin. In the four typical administrative regions in northern Xinjiang, the annual mean DSSR (ranging from 551.60 to 586.09 W/m2) was lower than that in the five typical administrative regions in southern Xinjiang (ranging from 522.10 to 623.62 W/m2). These spatial variations stem from a complex interplay of factors, including latitude, altitude, solar altitude angle, and sunshine duration. The variations in seasonal average DSSR aligned closely with variations in the solar altitude angle, with summer (774.76 W/m2) exhibiting the highest values, followed by spring (684.86 W/m2), autumn (544.76 W/m2), and winter (422.74 W/m2). The monthly average DSSR showed a unimodal distribution, peaking in June (792.94 W/m2) and reaching its lowest level in December (363.06 W/m2). Overall, our study findings enhance the current understanding of the spatiotemporal distribution characteristics of DSSR in Xinjiang and provide certain references for the management of clean energy development in this region.
分类： 核科学技术 >> 核科学与技术 提交时间： 2025-07-06
摘要： Recently, machine learning has become a powerful tool for predicting nuclear charge radius $R_{\mathrm{C}}$, providing novel insights into complex physical phenomena. This study employs the continuous Bayesian probability (CBP) estimator and the Bayesian model averaging (BMA) to optimize the predictions of $R_{\mathrm{C}}$ from sophisticated theoretical models. The CBP estimator treats the residual between the theoretical and experimental values of $R_{\mathrm{C}}$ as a continuous variable, deriving its posterior probability density function (PDF) from Bayesian theory. The BMA method assigns weights to models based on their predictive performance for benchmark nuclei, thereby accounting for each model’s unique strengths. In global optimization, the CBP estimator improves the predictive accuracy of the three theoretical models by about 60\%. In extrapolation analyses, it consistently achieves an improvement rate of approximately 45\%, demonstrating the robustness of the CBP estimator. Furthermore, the combination of the CBP and BMA methods reduces the standard deviation to below 0.02 fm, effectively reproducing the pronounced shell effects on $R_{\mathrm{C}}$ of the Ca and Sr isotope chains. The studies in this paper propose an efficient way to accurately describe $R_{\mathrm{C}}$ of unknown nuclei, with potential applications to research on other nuclear properties.
分类： 统计学 >> 经济统计学 提交时间： 2025-07-03
摘要： 根据国家统计局的数据，截至 2023 年，中国 60 岁及以上老年人口已超过 2.96 亿，占总人口的 21.1%。这一数据凸显了我国人口老龄化问题的严重性。在这种宏观背景下，传统的养老服务模式已经显示出明显的局限性。随着老年人口的持续增加，传统的养老方式正面临前所未有的压力和挑战。这不仅考验着社会福利体系，也迫使我们寻求创新的技术手段和服务模式来填补这一供给缺口。因此，智慧养老产业政策应运而生，它依靠先进的技术手段为老年人提供更高品质的生活。基于此，本文将探讨智慧养老产业政策干预下的“银发经济”，并全面分析这些外部和内部因素对经济增长的影响。本文基于 2008—2023 年中国省级面板数据，通过多维实证方法探讨智能养老政策对中国经济的影响机制，并重点关注资本投资、劳动效率和消费结构带来的中介效应。首先，采用双差法（DID）评价智慧养老试点政策的经济效果，结果表明，该政策的实施使试点地区的GDP增长率平均提高了约1.8个百分点，智慧养老政策对经济增长产生了显著的积极影响。其次，本研究在省级层面检验其机制，并采用中介效应模型发现，智能养老政策通过资本投入、劳动力供给和消费结构 3 条路径促进国内经济发展。当城市老龄化程度较低时，这种效果可能会减弱。最后，采用阈值模型分析智慧养老产业政策的异质性。当该地区人口老龄化，经济快速发展时，政策对经济发展的积极影响更加显著。研究表明，智慧养老产业政策通过促进产业结构升级、倒逼技术创新和需求侧激活的三重机制，有效促进了国民经济增长。建议构建“需求识别—技术赋能—政策协同”的立体化发展体系，针对区域老龄化和区域经济差异实施梯度产业政策。
分类： 物理学 >> 核物理学 提交时间： 2025-06-30
摘要： The full configuration interaction quantum Monte Carlo (FCIQMC) method, originally developed in quantum chemistry, has also been successful in both molecular and condensed matter systems. Another natural extension of this methodology would be its application to nuclear structure calculations. We have developed the FCIQMC approach for studying nuclear systems. To validate the method, we applied FCIQMC to a small model space where standard shell model remain computationally feasible. Specifically, we performed calculations for Fe isotopes using pf-shell GXPF1A interaction and compared the results with those obtained from standard shell model calculations. To further demonstrate the capabilities of FCIQMC, we investigated its performance in systems exhibiting strong correlations, where conventional nuclear structure models are less effective. Using an artificially constructed strongly correlated system with a modified GXPF1A interaction, our calculations revealed that FCIQMC delivers superior results compared to many existing methods. Finally, we apply FCIQMC to Mg isotopes in the sdpf-shell model space, showing its potential to perform accurate calculations in large model spaces that are inaccessible to the shell model due to the limitations of current computational resources.
分类： 环境科学技术及资源科学技术 >> 环境科学技术及资源科学技术其他学科 分类： 统计学 >> 经济统计学 提交时间： 2025-06-28
摘要： In alignment with China’s national strategic plan, Zhejiang Province officially launched the World Bank-financed "Zhejiang Qiandao Lake and Xin’an River Basin Water Resources and Ecological Environment Protection Project" in November 2018. This paper uses an ARIMAX INTERVENTION model to quantitatively assess the project’s phased effectiveness in protecting Qiandao Lake’s water resources. Controlling for natural factors such as temperature and precipitation, as well as other ongoing environmental initiatives (e.g., the Five Waters Co-governance, the River and Lake Chief System, and the Water Fund project), the results indicate that the World Bank-supported Qiandao Lake project has progressively demonstrated significant governance effectiveness since its implementation. However, improvement in several water quality indicators appears to have reached a bottleneck. To maintain or further enhance water quality, continued investment in green finance and environmental technology remains necessary.
分类： 物理学 >> 核物理学 提交时间： 2025-06-20
guo, Dr. zhiqi
Yang, Dr. Wenhua
Han, Dr. Jingyi
Zhang, Prof. Shuo
Li, Dr. Zhan
zhang, Dr. chunhui
Zhu, Prof. Dingjun
Shao, Prof. Jianxiong
摘要： As a key instrument for measuring neutron flux within a reactor core, the signal current of a Self-Powered Neutron Detector (SPND) is subject to change due to continuous material burnup.Accurately accounting for the long-term evolution of SPND signals is essential for reliable power monitoring and safe reactor operation. This study focuses on the Rhodium Self-Powered Neutron Detector (Rh-SPND) and, within the context of a typical Pressurized Water Reactor (PWR), develops a predictive model for signal current variation using a Back Propagation Neural Network (BPNN). The model incorporates changes in emitter material composition due to burnup and utilizes a layered approach to calculate the radial distribution of burnup. Key parameters such as beta electron generation rate, escape probability, gamma photon generation, and gamma-induced electron escape rate are all taken into account. Results show that over a 10-year period at a neutron flux of 1×10¹⁴ n/(cm²•s), the smaller the radius of the rhodium wire, the greater the variation in detector sensitivity. Specifically, a 0.1 mm wire radius results in a 51.3% sensitivity reduction, while a 1 mm wire radius yields a 25.2% reduction. The proposed model enables accurate sensitivity compensation for Rh-SPNDs over time, thereby minimizing neutron flux measurement errors and enhancing reactor safety and stability.
分类： 物理学 >> 核物理学 提交时间： 2025-06-16
摘要： Within the framework of the dinuclear system (DNS) model by implementing the cluster transfer into the dissipation process, we systematically investigated the energy spectra and the angular distribution of the preequilibrium clusters (n, p, d, t, $^{3}$He, $\alpha$, $^{6,7}$Li, $^{8,9}$Be) in the massive transfer reactions of $^{12}$C+$^{209}$Bi, $^{14}$N+$^{159}$Tb, $^{14}$N+$^{169}$Tm, $^{14}$N+$^{181}$Ta, $^{14}$N+$^{197}$Au, $^{14}$N+$^{209}$Bi, $^{58,64,72}$Ni+$^{198}$Pt near the Coulomb barrier energies. It is found that the neutron emission is the most probable in comparison with the charged particles and the $\alpha$ yields are comparable with the hydrogen isotopes in magnitude. The preequilibrium clusters are mainly produced from the projectile-like and target-like fragments in the evolution of dinuclear system. The kinetic energy spectra manifest the Boltzmann distribution and the Coulomb potential influences the structure. The preequilibrium clusters follows the angular distribution of multinucleon transfer fragments.
分类： 数学 >> 应用数学 提交时间： 2025-06-09
摘要： A fractional-order proportional-derivative controller is designed to address bifurcation issues in a dual-time-delay fractional-order predator-prey model. By selecting different delays as bifurcation parameters, the stability and Hopf bifurcation conditions of the controlled system are derived. The results show that the fractional order, delays and control parameters play an important role on the stability and Hopf bifurcation of the system. By selecting reasonable system parameters (fractional order, delays, and control parameters), suitable system control strategies can be devised. Finally, the key findings of this study are verified through numerical examples.
分类： 天文学 >> 天文仪器与技术 提交时间： 2025-06-03 合作期刊: 《Astronomical Techniques and Instruments》
摘要： To address the installation challenges of a 2-m ring Gregorian telescope system, and similar optical systems with a small width-to-radius ratio, we propose a detection method combining local interferometry with a comparison model. This method enhances the precision of system calibration by establishing a dataset that delineates the relationship between secondary mirror misalignment and wavefront aberration, subsequently inferring the misalignment from interferometric detection results during the calibration process. For the 2-m ring telescope, we develop a detection model using five local sub-apertures, enabling a root-mean-square detection accuracy of 0.0225λ ( λ= 632.8 nm) for full-aperture wavefront aberration. The calibration results for the 2-m Ring Solar Telescope system indicate that the root-mean-square value of sub-aperture wavefront aberration reaches 0.104λ , and the root-mean-square value of spliced full-aperture measurement yields reaches 0.112λ. This method offers a novel approach for calibrating small width-toradius ratio telescope systems and can be applied to the calibration of other irregular-aperture optical systems.
分类： 数学 >> 建模与仿真 分类： 语言学及应用语言学 >> 语言学及应用语言学 分类： 计算机科学 >> 自然语言理解与机器翻译 提交时间： 2025-06-03
摘要： Natural language is considered closely intertwined with human cognition, with linguistic structures posited to offer profound insights into the cognitive system. However, as a coding system, natural language encodes diverse objects into unified forms; its prominent formal features capture people’s attention, such as lexical combinatorial rules, which tend to overshadow those form-independent structures. Here, I present knowledge-level, logic-level, task-level, and model-level semantic structures inherent in natural language. These structures are discovered by shifting the research focus from coding forms of natural language to the objects they encode, unveiling different semantic layers integrated within sentences. The cognitive functions of these structures are evident both in themselves and in models developed from them. I therefore introduce four models to demonstrate their capabilities in memorization, reasoning, learning, natural language generation, and understanding. These findings advance our understanding of natural language and provide a framework for investigating the cognitive system’s information processing through structural analysis of natural language.
分类： 物理学 >> 核物理学 提交时间： 2025-05-30
Zhang, Dr. Ming-Hao
Wang, Miss Mei-Chen
Zou, Dr. Ying
Niu, Dr. Qing-Lin
Zhang, Dr. Gen
Zhang, Dr. Feng-Shou 张丰收
摘要： In the synthesis of new superheavy nuclei, the various long half-lives of Pu and Cm isotopes render them promising as target materials for the fusion reactions. An investigation into the isotopic dependence of the actinide targets is important to select optimal reaction systems. Based on the dinuclear system model with double-folding potential, the impact of the target isotope is investigated for the reactions $^{48}$Ca+$^{239,240,242,244}$Pu. The reaction systems with the $^{242-248}$Cm targets and the $^{45}$Sc, $^{50}$Ti, $^{51}$V, $^{54}$Cr, $^{55}$Mn projectiles are investigated for the synthesis of new isotopes $^{284-290}$Ts, $^{289-293,295}$Og, $^{290-296}$119, $^{293-299}$120, $^{294-300}$121. The isotopic dependence of the Cm targets reveals an ascending trend of the maximal ER cross section coupled with an odd-even effect as the neutron number of the target increases, and the $^{247}$Cm target emerges promising in future experiments. The optimal reactions for producing new superheavy elements with $Z$ = 119-121 are predicted to be the reactions $^{51}$V+$^{245}$Cm, $^{54}$Cr+$^{247}$Cm and $^{55}$Mn+$^{247}$Cm with the maximal ER cross sections of 144 fb, 0.877 fb and 0.052 fb, respectively.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 分类： 计算机科学 >> 自然语言理解与机器翻译 提交时间： 2025-05-27
摘要： The introduction of the transformer architecture in 2017 (cf. [VSP2017]) marked the most striking advancement in natural language processing. The transformer is a model architecture relying entirely on an attention mechanism to draw global dependencies between input and output. However, we believe there is a gap in our theoretical understanding of what the transformer is, and why it works physically. In this paper, from a physical perspective on modern chips, we construct physical models in the Fock space over the Hilbert space of tokens realizing large language models based on a transformer architecture as open quantum systems. Our physical models underlie the transformer architecture for large language models.
分类： 物理学 >> 核物理学 提交时间： 2025-05-27
摘要： The Shanghai High repetition rate XFEL and Extreme light facility (SHINE) utilizes high-Q 1.3 GHz superconducting radio-frequency (SRF) cavities for particle acceleration. These cavities, with an ultra-narrow bandwidth of approximately 32 Hz, are highly susceptible to Lorentz force detuning (LFD) and microphonics, which can destabilize the cavity resonance frequency and compromise system performance. This paper presents a novel detuning compensation scheme that combines an autoregressive least-mean-square (LMS) adaptive filter and active noise control (ANC) in a parallel configuration to mitigate microphonic-induced detuning. A real-time simulation model, incorporating the cavity's mechanical eigenmodes, was developed to evaluate the proposed approach. Simulation results demonstrate significant reductions in amplitude and phase errors by approximately 90% and 70%, respectively, compared to the open-loop tuning configuration, achieving the stringent operational requirements. This study introduces an innovative detuning compensation strategy for high-Q SRF cavities, providing a robust framework for optimizing RF system design and ensuring stability in complex noise environments.
分类： 物理学 >> 地球物理学、天文学和天体物理学 提交时间： 2025-05-24
摘要： In our previous work (i.e., Ref. [14]), we proposed a special Lorentz violation model, which is characterized by that the maximum energy of a particle with mass is finite and proportional to its rest mass rather than infinite predicted by the Lorentz model. In this paper, we continue to investigate the impact of the Lorentz violation model on the curved spacetime. Firstly, we proposed a method for obtaining the spacetime metric without external fields corresponding to this Lorentz violation model. Then, we used this new metric to analyze the proper acceleration of a particle fixed in the Schwarzschild spacetime. To our surprise, we found that when the particle is less than a certain distance from the event horizon of the Schwarzschild black hole, the closer it is to the event horizon, the smaller its proper acceleration becomes, and the proper acceleration drops to 0 when reaching the event horizon. By analogy with the quark model in particle physics, we can also call this phenomenon the ”asymptotic freedom” in Schwarzschild spacetime, which shows us a different black hole.
分类： 计算机科学 >> 自然语言理解与机器翻译 分类： 计算机科学 >> 计算机软件 分类： 计算机科学 >> 计算机应用技术 提交时间： 2025-05-20
摘要： Domain-specific QA systems require not just generative fluency but high factual accuracy grounded in structured expert knowledge. While recent Retrieval-Augmented Generation (RAG) frameworks improve context recall, they struggle with integrating heterogeneous data and maintaining reasoning consistency. To address these challenges, we propose DO-RAG, a scalable and customizable hybrid QA framework that integrates multi-level knowledge graph construction with semantic vector retrieval. Our system employs a novel agentic chain-of-thought architecture to extract structured relationships from unstructured, multimodal documents, constructing dynamic knowledge graphs that enhance retrieval precision. At query time, DO-RAG fuses graph and vector retrieval results to generate context-aware responses, followed by hallucination mitigation via grounded refinement. Experimental evaluations in the database and electrical domains show near-perfect recall and over 94% answer relevancy, with DO-RAG outperforming baseline frameworks by up to 33.38%. By combining traceability, adaptability, and performance efficiency, DO-RAG offers a reliable foundation for multi-domain, high-precision QA at scale.
分类： 地球科学 >> 大气科学 提交时间： 2025-05-19 合作期刊: 《干旱区科学》
摘要： Recent years have witnessed increasingly frequent extreme precipitation events, especially in desert steppes in the semi-arid and arid transition zone. Focusing on a desert steppe in western-central Inner Mongolia Autonomous Region, China, this study aimed to determine the principle time-varying pattern of extreme precipitation and its dominant climate forcings during the period 1988–2017. Based on the generalized additive models for location, scale, and shape (GAMLSS) modeling framework, we developed the best time-dependent models for the extreme precipitation series at nine stations, as well as the optimized non-stationary models with large-scale climate indices (including the North Atlantic Oscillation (NAO), Atlantic Multidecadal Oscillation (AMO), Southern Oscillation (SO), Pacific Decadal Oscillation (PDO), Arctic Oscillation (AO), and North Pacific Oscillation (NPO)) as covariates. The results indicated that extreme precipitation remained stationary at more than half of the stations (Hailisu, Wuyuan, Dengkou, Hanggin Rear Banner, Urad Front Banner, and Yikewusu), while linear and non-linear time-varying patterns were quantitatively identified at the other stations (Urad Middle Banner, Linhe, and Wuhai). These non-stationary behaviors of extreme precipitation were mainly reflected in the mean value of extreme precipitation. The optimized non-stationary models performed best, indicating the significant influences of large-scale climate indices on extreme precipitation. In particular, the NAO, NPO, SO, and AMO remained as covariates and significantly influenced the variations in the extreme precipitation regime. Our findings have important reference significance for gaining an in-depth understanding of the driving mechanism of the non-stationary behavior of extreme precipitation and enable advanced predictions of rainstorm risks.
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