分类： 核科学技术 >> 核探测技术与核电子学 提交时间： 2025-06-12
摘要： While traditional gamma-gamma density (GGD) logging technology is widely utilized, its potential environmental risks have prompted the development of more environmentally friendly neutron-gamma density (NGD) logging technology. However, NGD measurements are influenced by both neutron and gamma radiation. In the logging environment, variations in formation composition indicate different elemental compositions, which affect neutron-gamma reaction cross-sections and gamma generation. Compared to traditional gamma sources such as Cs-137, these changes can significantly impact the generation and transport of neutron-induced inelastic gamma rays, posing challenges for accurate measurements. To address this, a novel method is proposed, the method incorporates the mass attenuation coefficient function to account for the effects of various lithologies and pore contents on gamma-ray attenuation and therefore can achieve more accurate density measurements by clarifying the transport processes of inelastic gamma rays with varying energy and spatial distributions in varied logging environments. The method avoids the complex correction of the neutron transport and is verified through Monte Carlo simulations for its applicability across various lithologies and pore contents. showing thatthe absolute density errors are less than 0.02 g/cm3 in clean formations and demonstrating good accuracy. The research not only clarifies the NGD mechanism but also provides theoretical guidance for the application of NGD logging methods. Further research will be conducted regarding extreme environmental conditions and tool calibration.
分类： 统计学 >> 经济统计学 提交时间： 2025-06-12
摘要： 车辆保险定价作为精算学的核心问题之一，影响着保险公司的盈利能力和资金流动性。本文献综述对各地区不同的车险发展进行了简要阐述，并讨论了车险费率拟定系统、特殊车险定价、无索赔折扣奖惩理论以及准备金评估方法等问题相关的历史研究。本文献综述以统计分布和模型结构为切入点，剖析模型的具体运作逻辑，对利用Tweedie分布族建立指数保险的定价模型，利用广义加性模型与LocalGLMnet建模方法等基于频率学派和贝叶斯学派的大多数方法建立定价框架和准备金评估的文献进行了集中讨论。为了体现风险建模思想对真实业务的应用效果，本文还列入BMS系统、GAM准备金评估模型等相关文献，基于此探索一种车辆保险中的风险动态调整机制的构造方式。在准备金研究方面，包括同质性和异质性假设的评估方法的文献，具体为运用链梯法等传统方法对总体事故赔付数据进行预测建模，以及在已有算法模型基础上使用机器学习技术改进模型并对个体事故赔付数据进行预测建模两大类。除了一般车险之外，还对天气指数保险进行了研究探讨，并且借助于遥感数据和地面观测数据建立多维输入方式，以提高模型针对极端气象事件的识别能力。实证发现，该模型在赔付稳定性以及区域风险差异方面表现较好。基于数据层面，在本文献综述选择了真实的车辆保险和天气保险赔付真实数据作为实例的研究，并针对其中不同的建模方式设置对照组，对预测效果的异同点进行了分析与评价。本文集中于建构一套财产保险领域可复制推广的保险建模方法，综合考虑监管、数据建模等多方面因素，提高财产保险公司量化定价的能力，以促进财产保险业在数字化转型、定价精算等方面获得新的实践经验和理论依据。
分类： 机械工程 >> 机械制造自动化 提交时间： 2025-06-12
摘要： 粉床金属增材制造常常受到由于气体滞留和小孔不稳定性导致的高孔隙率问题的困扰。本文首次提出了一种突破性的方法：通过低脉冲能量同轴激光冲击原位熔池调制。将附加脉冲激光束耦合到选择性激光烧结系统，以实现低孔隙率高质量金属零件制造。原位监测表明，所用的激光冲击方法抑制了烧结过程中的严重飞溅，有助于实现低孔隙率。计算机断层扫描（CT）可以量化孔隙的体积、直径和球形度。结果表明，在最佳脉冲激光条件下，打印的316L不锈钢块的孔隙率显著降低了86％，达到小于0.016％。同时，孔隙的形状和大小得到了有利的控制。
分类： 心理学 >> 社会心理学 提交时间： 2025-06-11
摘要： 当下社会，人们在相亲择偶时日趋“明码标价”。本研究将此现象概念化为择偶中的计算心态，并提出在人际关系的建立与结束更加自由的高关系流动性环境中，此种将择偶信息转换为流畅易加工的量化指标的认知策略具有认知减负的适应性功能。通过相亲网站文本分析、问卷测量和实验室实验，三个研究(4个子研究)分别从地区和个体水平上揭示了关系流动性与择偶计算心态之间的相关和因果关系。研究结果将关系流动性的心理后效拓展至个人择偶领域，一方面在理论上丰富了对于个体如何适应特定社会生态环境的认识，另一方面可在实践上为制定符合社会转型期大众择偶心理的政策或营销策略提供参考。
分类： 核科学技术 >> 粒子加速器 提交时间： 2025-06-11
摘要： 上海质子治疗装置（SAPT）是首台国产质子治疗示范装置，旋转机架是质子治疗装置中的重要组成部分，等中心精度达±0.275mm，优于国际主流设备，要求高运动定位精度和可靠性。本研究揭示了位于瑞金质子中心360°旋转机架的研制和等中心精度的研究并与实测结果进行对比。通过ANSYS对旋转机架进行有限元分析，使用激光跟踪仪测量实际变形情况，验证了典型工况下等中心点处的精度要求并进行原因分析，验证了国产旋转机架的可靠性。
分类： 信息科学与系统科学 >> 信息科学与系统科学基础学科 分类： 数学 >> 计算科学理论 分类： 物理学 >> 交叉学科物理及相关领域的科学与技术 提交时间： 2025-06-11
摘要： We present a new method for structural sequence analysis grounded in Algorithmic Information Theory (AIT). At its core is the Ladderpath approach, which extracts nested and hierarchical relationships among repeated substructures in linguistic sequences---an instantiation of AIT’s principle of describing data through minimal generative programs. These structures are then used to define three distance measures: a normalized compression distance (NCD), and two alternative distances derived directly from the Ladderpath representation. Integrated with a $k$-nearest neighbor classifier, these distances achieve strong and consistent performance across in-distribution, out-of-distribution (OOD), and few-shot text classification tasks. In particular, all three methods outperform both gzip-based NCD and BERT under OOD and low-resource settings. These results demonstrate that the structured representations captured by Ladderpath preserve intrinsic properties of sequences and provide a lightweight, interpretable, and training-free alternative for text modeling. This work highlights the potential of AIT-based approaches for structural and domain-agnostic sequence understanding.
分类： 核科学技术 >> 粒子加速器 提交时间： 2025-06-11
摘要： 预氧化是制备聚丙烯腈基（PAN）碳纤维的关键步骤，γ辐照是热处理预氧化过程优化的有效手段。然而，目前γ辐照与热处理时序对预氧化作用效果和机制尚不明确。对此，本文采用分子动力学模拟方法，从分子链形态演变、物种变化以及反应路径等方面，分析了γ辐照与热处理时序对PAN纤维预氧化过程的结构变化的影响。结果表明，先辐照后加热（γ-T）的处理方式使PAN分子链段形态更稳定，预氧化产物种类更集中，且这种方式可促使PAN分子链更早地产生较多的自由基，以此加速环化、氧化、交联等反应进程，并在加热过程中实现二次交联，进而提升PAN纤维预氧化程度。而先加热后辐照（T-γ）的处理方式因热处理阶段PAN分子链形成自由基少，导致交联结构相对较少，在辐照过程中易造成分子链断裂，产物种类繁杂，致使最终预氧化效果相对欠佳。本研究揭示了γ辐照与热处理时序对PAN纤维预氧化过程作用机制，为PAN纤维预氧化过程中结构调控提供理论支撑。
分类： 心理学 >> 临床与咨询心理学 提交时间： 2025-06-11
摘要： 心理传记学关注于非凡人物的研究，其转向普通个体的生命历程则有赖于心理传记疗法的开创和实践。心理传记疗法的理论核心是基于舒尔茨提出的"原型情景"概念，即个体生命故事中的关键情景和冲突可以解释其当下心理问题，并成为治疗的关键切入点。然而，“原型情景"概念在理论上仍较为模糊，如原型情景内涵、特点及识别等问题需进一步澄清。本研究提出了“原型情景"作为心理传记学与心理传记疗法的理论契合历经生成、激活、作用三个阶段，具有非唯一性、重复性与象征性、情感凝聚性、可迭代性、可建构性。研究进一步提出了原型情景提取的洋葱模型，阐释了“原型情景"在理解与干预个体心理问题中的应用。
分类： 物理学 >> 核物理学 提交时间： 2025-06-10
摘要： CANDLE reactors are a type of fast reactor that burn depleted uranium or nature uranium without chemical reprocessing. One of the crucial challenges in practice is high material radiation damage for the CANDLE reactor. Double solitary waves reactor (DSWR), with double separated ignition zones, were proposed to reduce material radiation damage and still could maintain total output power. In this study, a fast spectrum reactor cooled by liquid mental was adopted and the optimization scheme of the DSWR was performed to reduce material radiation damage. The optimization schemes included ignition zone fuel enrichment, fuel density. The parameters, such as infinite medium factor, fuel burnup, the density of U-235, U-238 and Pu-239 were demonstrated to achieve the design goals, which were reduction the discharged fuel burnup from 380 GWd/T to approximately 200 GWd/T to yield to engineering technology.
分类： 核科学技术 >> 核科学与技术 提交时间： 2025-06-10
摘要： 为了满足普通高校对反应堆教学与科研的需求，基于日趋流行的Modelica仿真技术，构建主要用于培训、研究及同位素生产的TRIGA（Training, Research, Isotopes, General Atomic）反应堆的点堆中子动力学、氙和钐中毒、温度反馈和集总参数热工动态模型，进行了大阶跃反应性扰动的脉冲启堆和紧急停堆仿真，以及小阶跃反应性扰动的功率调节仿真。脉冲峰功率、脉冲释放能量、脉冲半高宽、最大氙和钐浓度及功率变化等关键动态响应结果与实验或理论结果基本相符。因此，本研究建立的Modelica仿真模型能用于TRIGA研究堆基本动态特性的预测，为反应堆教学和科研提供支撑。
分类： 计算机科学 >> 计算机应用技术 提交时间： 2025-06-10
摘要： Mathematical reasoning presents a significant challenge for Large Language Models (LLMs) as it requires ensuring the correctness of each reasoning step. Researchers have been strengthening the mathematical reasoning abilities of LLMs through supervised fine-tuning, but due to the inability to suppress incorrect outputs, illusions can easily arise. Recently, Direct Preference Optimization (DPO) has been widely adopted for aligning human intent by using preference data to prevent LLMs from generating incorrect outputs. However, it has shown limited benefits in long-chain mathematical reasoning, mainly because DPO struggles to effectively capture the differences between accepted and rejected answers from preferences in long-chain data. The inconsistency between DPO training and LLMs’ generation metrics also affects the effectiveness of suppressing incorrect outputs. We propose the Multi-Granularity Direct Preference Optimization (MDPO) method, optimizing the mathematical reasoning of LLMs at three granularities: Solution2Solution, Inference2Inference, and Step2Step. Solution2Solution focuses on the correctness of entire long-chain reasoning; Inference2Inference concentrates on logical reasoning between steps; Step2Step corrects computational errors in steps, enhancing the computational capabilities of LLMs. Additionally, we unify the training objectives of the three granularities to align with the generation metrics. We conducted experiments on the open-source models Qwen2 and Llama3, achieving improvements of 1.7% and 0.9% on the GSM8K dataset, and 2.3% and 1.2% on the MATH dataset, outperforming DPO and other DPO variant methods. Furthermore, we also provide a pipeline for constructing MDPO training data that is simple and does not require manual annotation costs.
分类： 心理学 >> 管理心理学 提交时间： 2025-06-10
摘要： 即兴行为是一种兼具即时性和创造性的行为模式。然而，目前结合其本质内涵以详述即兴行为生成机制的研究尚显不足。为此，本研究整合知识联结理论与激活理论，分别契合即兴行为的创造性与即时性特征，探讨了时间压力下知识存量对个体即兴行为的影响机制。研究1 (N=163)和研究2(N=163)分别以大学生及组织员工为被试，通过实验发现知识存量通过增强知识转化进而促进个体即兴行为；尤其在中时间压力情境下，上述关系更为强烈；研究3(N=201)开展多时点配对问卷调查，进一步确证了时间压力在知识存量对知识转化的影响过程中发挥倒U 型调节效应，进而通过知识转化作用于即兴行为。通过3个研究得出结论：在中等时间压力下，知识存量通过影响知识转化从而更有利于激发个体即兴行为；而在高或低时间压力下则更弱，以此全面揭示时间压力作用下知识存量赋能即兴行为的生成过程机制，这为有效依据其特征进行理论整合提供了新视角，并对理解即兴行为的动态性和复杂性具有积极的意义。
分类： 物理学 >> 核物理学 提交时间： 2025-06-10
Zhu, Dr. Peng
Li, Mr. Ming-Tao
Li, Mr. Zhi-Ping
Wang, Dr. Lin
Linyan, Ms. Rong
Ouyang, Dr. Huafu
Zhang, Dr. Yu-Liang
He, Dr. Yongcheng
Xue, Mr. Kangjia
Wu, Mr. Xuan
Zhencheng, Dr. Mu
Jin, Dr. Dapeng
摘要： Boron neutron capture therapy (BNCT) is an advanced targeted radiotherapy that exploits the high affinity of the 10B nucleus for capturing neutrons. This therapy involves the use of neutron beams in combination with boron compounds, which preferentially accumulate in cancer cells. Recent advancements in accelerator-based neutron sources have propelled accelerator-based BNCT (AB-BNCT) to the forefront as a highly promising modality. This is due to its significant advantages, including reduced capital investment, simplified operation, and ease of implementation in hospitals worldwide. In 2022, the first fully independent AB-BNCT facility in China, located at Dongguan People's Hospital, was successfully developed by the Institute of High Energy Physics of the Chinese Academy of Sciences. The timing and fast interlock systems are two essential components of an accelerator facility. Designing a reconciled control system that integrates a timing system and a fast protection system characterized by high performance, stability, and reliability for accelerators is essential. Consequently, a novel architecture, which is based on in-house hardware within a compact PCI platform, has been designed and adopted for timing systems and fast protection systems to meet the requirements of AB-BNCT accelerators. The timing and fast interlock systems have been intricately involved in and have successfully completed the full suite of equipment commissioning and beam-target experiments, meeting the requirements for precise treatment in-hospital AB-BNCT. This paper focuses on a comprehensive description of the integrated system architecture, detailing the hardware and software development, and the strategy underlying highly efficient interlocking functions. Additionally, the testing and operational status related to the system's implementation are validated for reliability, underscored the expanded applications in the field of cancer treatment.
分类： 图书馆学、情报学 >> 图书馆学 提交时间： 2025-06-10
摘要： 【目的】研究预印本平台价值影响因素模型并对其进行实证，为预印本平台价值的更好发挥提供理论依据与实践指导。【方法】采用文献调研和内容分析法设计价值量表，并采用问卷调查的方式，借助回归方程模型，对模型进行检验。【结果】从科研人员视角出发，平台属性特质和科研人员个人习惯具有显著的正向关系；平台属性特质和科研人员自我效能具有显著的正向关系；平台属性特质和科研人员感知结果具有显著的正向关系；科研人员感知结果和其对预印本平台的态度具有显著的正向关系；科研人员对预印本平台的态度对其个人认知预印本平台价值的（行为）意向具有显著的正向影响。从出版人员视角出发，平台属性特质和出版人员个人习惯具有弱显著的正向关系；平台属性特质和出版人员自我效能具有弱显著的正向关系；平台属性特质和出版人员感知结果具有显著的正向关系；出版人员感知结果和其对预印本平台的态度具有弱显著的正向关系；出版人员对预印本平台的态度对其个人认知预印本平台价值的（行为）意向具有显著的正向影响。从科研资助方视角出发，平台属性特质和科研资助方感知结果具有较弱显著的正向关系；科研资助方感知结果和其对预印本平台的态度具有较弱显著的正向关系；科研资助方对预印本平台的态度对其个人认知预印本平台价值的（行为）意向具有显著的正向影响。【结论】不同利益相关者对待预印本平台价值态度存在较大差异，影响因素之间关联程度也存在不同，若想整体提升预印本平台价值，还应面向不同利益相关者针对不同因素入手。
分类： 核科学技术 >> 核科学与技术 提交时间： 2025-06-10
摘要： 液态金属热管是空间探测飞行器的重要导热元件，同时具有良好的传导热能力和等温性能。但是，在空间探测任务中，钠热管会处于低于甚至远低于设计工况下运行，使得液态金属工质在冷凝段冻结沉积，造成管内工质向冷凝段迁移。文中采用实验和数值模拟两种方法，研究了质量迁移现象对钠热管工作特性的影响。研究结果表明，钠热管发生质量迁移后的再启动过程存在传热滞后效应，导致散热不及时，危害系统整体运行的稳定性和可靠性。冻结沉积部位的吸液芯内被固态工质堵塞，无法再参与冷凝散热过程，使得钠热管的有效散热长度明显缩短，最终完全失效。质量迁移现象将导致热管的传导热能力和等温特性受到影响，进而影响系统整体的热稳定性。
分类： 物理学 >> 核物理学 提交时间： 2025-06-10
Qu, Dr. Shuiyin
Yan, Dr. Shu-chang
Wu, Dr. Zhen
Zhou, Dr. Yang
Hu, Dr. Ankang
Liu, Dr. Hongming
QIU, Dr. RUI 邱睿
LI, Prof. JUNLI
摘要： Monte Carlo (MC) simulations are considered the gold standard for calculating radiation dose in complex radiation fields. However, these simulations often require substantial computational resources. Based on our team's existing GPU modules for photons and electrons/positrons, this research developed neutron GPU physics modules including elastic scattering, inelastic scattering, radiative capture, and fission. These were integrated into the Neudep (GPU-based NEUtron-photon-electron/positron coupled Dose Estimation Program). This program enables coupled multi-particle transport of neutrons, photons, and electrons/positrons across broad energy ranges and incorporates comprehensive physics for all particle interactions. During neutron interactions, photons and secondary neutrons are produced. These photons undergo various physical processes: the photoelectric effect, Compton scattering, and pair production, generating photoelectrons, Compton electrons, and recoil electron-positron pairs, respectively. The associated electron interactions include bremsstrahlung, ionization, and multiple scattering. Bremsstrahlung, in particular, gives rise to secondary photons. Additionally, positron annihilation results in the production of secondary photons. All these secondary particles are stored in a stack and are transported only after the primary neutron transport process is completed. The Neudep program was validated for accuracy and tested for computational efficiency using both a homogeneous WaterPhantom and the Chinese adult male voxel model (CRAM). The results indicate that the energy deposition discrepancies between Neudep and the reference Monte Carlo code are less than 2%, with neutron incident energies of 3 MeV showing deviations of less than 0.5%. Organ dose differences generally remain within 5%. While maintaining computational accuracy, the Neudep program efficiently simulates 1 million neutrons in just 2 seconds. Additionally, the transport time for 10 million neutrons through a complex human model can be reduced to under one minute. Neudep can reduce computation times by 78-5000 times compared to traditional CPU-based Monte Carlo software. This tool demonstrates tremendous potential for rapid and accurate dose calculations.
分类： 医学、药学 >> 临床医学 提交时间： 2025-06-10 合作期刊: 《中国全科医学》
摘要： 背景 阿尔茨海默病（AD）是一种复杂的神经系统退行性疾病，其治疗给患者及家庭带来沉重的负担。近年来中成药治疗AD的临床研究不断增加，但研究的证据支撑情况尚不清楚。目的 分析近5年中成药治疗阿尔茨海默病的临床研究相关证据情况。方法 检索2019年1月—2024年12月的8个中英文数据库（中国知网、万方数据知识服务平台、维普网、中国生物医学文献服务系统、PubMed、Web of Science、Cochrane Library、Embase数据库）中收录的中成药治疗AD的文献，采用文字结合图表的形式展示证据分布特征。结果 最终纳入临床试验82篇，系统综述/Meta分析30篇，网状Meta分析9篇，指南/专家共识/路径等7篇，系统评价再评价1篇，卫生技术评估1篇。近年来中成药治疗AD的关注度呈波动下降的趋势，临床研究与评价集中于21种中成药，其中对口服中成药复方苁蓉益智胶囊和复方海蛇胶囊关注度最多，注射剂主要为银杏叶提取物。临床研究主要为单中心、小规模的随机对照试验，且文献质量普遍不高。在结局指标选择方面，主要侧重于认知功能指标、替代结局指标和生活质量等指标，指标缺乏中医辨证论治的特色，指标的选择、测量等缺乏规范性。系统综述/Meta分析的整体质量较低，方法学质量以及临床实践指南和专家共识的制定和报告规范性均有待进一步提高。结论 中成药治疗AD已开展了一些单中心、小样本的临床研究，今后需结合中药治疗AD的临床诊疗实践特点进一步开展多中心、大样本、高质量的临床研究，以利于形成高质量的临床证据，为中成药治疗AD提供相关参考。
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2025-06-09
摘要： 发轫于20世纪初的相对论和量子论革命没有带来预期的终极物理学理论，相反，21 世纪的物理学面临着更多困惑和深层危机。大统一理论的持续可见不可及迫使人们对物理学的理论基础进行科学哲学审视。这种反思发现了经典物理和现代物理在自然观方面的深刻分歧，包括物质观、时空观和运动观。通过调整补充，在统一的自然观基础上诞生了现实物理学理论。现实物理学奉行客观性原则，强调物质世界和物理规律的客观实在性，追求物理理论的自然刚性。现实物理学包括粒子流场论、粒子动力学和粒子统计学理论，它们修正和发展了经典力学、电动力学和统计力学，在新自然观基础上统一了宏观（宇观）力学和微观（量子）力学。本文介绍现实物理学的理论体系和主要内容，结合重要结论阐述现实物理学的科学哲学观点和思想认识路线。现实物理学开拓了通往物理终极目标的道路，随着理论基础的完善和应用的扩展，必将在探索未知世界的进程中发挥巨大作用。
分类： 其他 提交时间： 2025-06-09
摘要： 为了监测并分析合肥光源运行过程中的束流损失特性，开发了一套基于闪烁体探测器、条带电极束流位置监测器(Beam Position Monitor, BPM)和高速示波器的高时间分辨束流损失及束团位置同步监测系统。通过仿真与实测波形对比，验证了系统输出束损脉冲波形的准确性。基于非对称高斯函数拟合的方法提取了束损脉冲信号特征参数。结合HOTCAP技术从条带电极信号中提取了逐束团电荷量及位置信息。基于合肥光源储存环的特殊填充模式实现束损数据和BPM数据束团编号的关联对齐。利用该系统监测了合肥光源注入瞬态及注入后稳态运行条件下的束损情况，结果表明：稳态运行过程中逐束团束损与电荷量分布呈现显著关联性，与随机束损的理论预期相符；注入瞬态过程中首次观察到补注束团及其之后第14号储存束团同时存在显著束损的现象。
分类： 物理学 >> 核物理学 提交时间： 2025-06-09
摘要： To mitigate the dark pulse and attain low background level measurements, the liquid scintillation counter (LSC) is generally equipped with two or three photomultiplier tubes (PMT) for coincidence measurements. However, traditional identification method in the LSC only utilize the anode pulse from a single PMT to identify alpha/beta particles, which limits their ability to identify particles. We developed a three-channel Convolutional Neural Network (TCNN) model, which integrates pulses from three PMT anodes to identify particle categories. Anode pulses are organized into a shape (3,512) and subsequently fed into the TCNN for alpha/beta pulse discrimination. To train and validate TCNN, we prepared two samples: 241Am sample as alpha emitter and 90Sr/90Y sample as beta emitter. In the validation set, TCNN performed significantly better than traditional convolutional neural networks (CNN) in identifying alpha/beta pulses, achieving accuracy, recall, and F1 score of 99.44%, 99.23%, and 99.34%, respectively. We also prepared a mixed-emitter sample exhibiting a β activity of approximately 172Bq and an α activity of 98Bq to evaluate the impact of the TCNN on the spectral performance in practical applications. Firstly, the category of the pulse from the sample is identified by the TCNN, and then it’s height is recorded in an α-MCA spectrum or β-MCA spectrum according to the identified category. The alpha particle peak in the α-MCA spectrum is used to evaluate spectral performance. The optimal detection limit for the alpha particle peak is 0.3337 cps, which shows a sensitivity increase of 31.16% compared to the CNN method. This indicates that the TCNN can effectively utilize the three-channel pulses to enhance the ability to distinguish between alpha and beta particles when analyzing both simultaneously, thereby significantly improving the sensitivity of the detector.
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