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STOCHASTIC ANALYSIS OF GROUNDWATER FLOW SUBJECT TO RANDOM BOUNDARY CONDITIONS

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Journal of Hydrodynamics 2008年第5期20卷 553-560页

作者： shi Liang-sheng yang jin-zhong CAI Shu-ying LIN Lin State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Wuhan 430072 China

A stochastic model was developed to simulate the flow in heterogeneous media subject to random boundary conditions. Approximate partial differential equations were derived based on the Karhunen-Loeve （KL） expansion and perturbation expansion. The effect of random boundary conditions on the two-dimensional flow was examined. It is shown that the proposed stochastic model is efficient to include the random boundary conditions. The random boundaries lead to the increase of head variance and velocity variance. The influence of the random boundary conditions on head uncertainty is exerted over the whole simulated region, while the randomness of the boundary conditions leads to the increase of the velocity variance in the vicinity of boundaries.

关键词： groundwater flow Karhunen-Loeve (KL) expansion hydraulic head random boundary variance

Late Paleozoic to early Mesozoic volcanic-sedimentary history of the southeastern margin of the Central Asian Orogenic Belt: Timing of uplift of the Inner Mongolia paleo-uplift

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Science China Earth Sciences 2025年第1期68卷 297-309页

作者： Wenxing HAO jin-Hui yang Guang ZHU State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences School of Resource and Environmental Engineering Hefei University of Technology

The Kulun region is located in the eastern Bainaimiao arc belt on the southeastern margin of the Central Asian Orogenic Belt(CAOB), adjacent to the North China Craton(NCC) to the south. This region records the closure of the PaleoAsian Ocean during the Paleozoic to early Mesozoic and is key to study the tectonic evolution of the northern margin of the *** conducted zircon U-Pb geochronology and Hf isotope analysis of volcanic-sedimentary and intrusive rocks in the Kulun region. The volcanic-sedimentary rocks were previously assigned an early Carboniferous age, but include volcanic rocks with ages of 267–266 Ma and sedimentary rocks with youngest detrital zircon age peaks of 265–244 Ma, which were intruded by a granite with an age of 242 Ma. This indicates that these rocks are actually middle Permian to Middle Triassic in age(267–242Ma) and correspond to the Qingfengshan and Liujiagou formations. Moreover, two volcanic rock samples have high εHf(t) values(+1.6 to +16.1) and relatively young two-stage Hf model ages(1095–327 Ma), indicating their sources associated with the CAOB. The age spectra and Hf isotopic characteristics of detrital zircons from the sedimentary rocks suggest that, during the middle Permian to Middle Triassic, the sedimentary provenance in the Kulun region was mainly the CAOB. However, by the Early Jurassic, the provenance changed to the NCC(i.e., the Inner Mongolia Paleo-uplift, IMPU). This result, combined with the development of a series of conglomerates on the northern margin of the NCC in the Late Triassic(i.e., Xingshikou, Xiaoyingzi,and Xiaohekou formations), indicates the Kulun region experienced an abrupt change in paleogeography during the Late Triassic, with the IMPU undergoing significant uplift and thus becoming the main sediment source in the Kulun region. Based on the Late Triassic alkaline igneous belt(235–215 Ma) in the IMPU, we speculate that this uplift was caused by detachment of the southward-subducting Paleo-Asian oceanic

关键词： Central Asian Orogenic Belt the North China Craton Zircon geochronology Hf isotopes Inner Mongolia Paleo-uplift

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发达地区农户小额信贷需求影响因素实证研究

广东农业科学 2014年第15期41卷 209-214页

作者：杨仕晋华南农业大学经济管理学院广东广州510642

对佛山农村地区的490户农户的信贷需求和小额信贷行为进行了调查分析,运用二元Logitstic模型,实证检验了发达地区农户小额信贷需求的影响因素。结果表明,发达地区农户正规信贷市场参与度高;农户对小额信贷需求意愿强烈,有正规信贷需求... 详细信息

对佛山农村地区的490户农户的信贷需求和小额信贷行为进行了调查分析,运用二元Logitstic模型,实证检验了发达地区农户小额信贷需求的影响因素。结果表明,发达地区农户正规信贷市场参与度高;农户对小额信贷需求意愿强烈,有正规信贷需求的农户对小额信贷的认可度高,且希望得到小额信贷的相关培训服务;与贫困地区农户信贷资金主要满足生活消费性用途不同的是,发达地区农户贷款以投资生产性用途为主;发达地区农户的信贷额度较大,但金融需求的满足率不高。计量分析表明:发达地区农户投资活跃度、家庭教育支出、小额信贷的认识性评价对农户小额信贷需求有显著正向影响;发达地区农户家庭耕地面积、投资规模、家庭年收入、农业收入、家庭固定资产价值对农户小额信贷需求有显著负向影响。

关键词：发达地区农村小额信贷需求影响因素二元Logitstic模型

Interpretable Machine Learning Method for Compressive Strength Prediction and Analysis of Pure Fly Ash-based Geopolymer Concrete

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Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 65-78页

作者： shi Yuqiong LI jingyi ZHANG yang LI Li Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas of Ministry of Education Northwest A&F Uni-versityYangling 712100China College of Water Resources and Architectural Engineering Northwest A&F UniversityYangling 712100China Chongqing Key Laboratory of Public Big Data Security Technology Chongqing 401420China Chongqing College of Mobile Communication Chongqing 401520China Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina National Rail Transit Electrification and Automation Engineering Technology Research Center(Hong Kong Branch) The Hong Kong Polytechnic UniversityKowloonHung HomHong KongChina

In order to study the characteristics of pure fly ash-based geopolymer concrete(PFGC)conveniently,we used a machine learning method that can quantify the perception of characteristics to predict its compressive *** this study,505 groups of data were collected,and a new database of compressive strength of PFGC was *** order to establish an accurate prediction model of compressive strength,five different types of machine learning networks were used for comparative *** five machine learning models all showed good compressive strength prediction performance on *** them,R2,MSE,RMSE and MAE of decision tree model(DT)are 0.99,1.58,1.25,and 0.25,*** R2,MSE,RMSE and MAE of random forest model(RF)are 0.97,5.17,2.27 and 1.38,*** two models have high prediction accuracy and outstanding generalization *** order to enhance the interpretability of model decision-making,we used importance ranking to obtain the perception of machine learning model to 13 *** 13 variables include chemical composition of fly ash(SiO_(2)/Al_(2)O_(3),Si/Al),the ratio of alkaline liquid to the binder,curing temperature,curing durations inside oven,fly ash dosage,fine aggregate dosage,coarse aggregate dosage,extra water dosage and sodium hydroxide *** temperature,specimen ages and curing durations inside oven have the greatest influence on the prediction results,indicating that curing conditions have more prominent influence on the compressive strength of PFGC than ordinary Portland cement *** importance of curing conditions of PFGC even exceeds that of the concrete mix proportion,due to the low reactivity of pure fly ash.

关键词： machine learning pure fly ash geopolymer compressive strength feature perception

Revealing and predicting the long-term biomechanical response of orthokeratology by developing a patient-specific computational model

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 156-168页

作者： Yifeng Li Zhuoran yang Ziming Yan Huibin shi Zhanli Liu Kaijie Wang Department of Engineering Mechanics School of Aerospace Engineering Tsinghua University Beijing Tongren Eye Center Beijing Tongren Hospital Capital Medical University Beijing Ophthalmology & Visual Sciences Key Lab

Orthokeratology(OK) is widely used for effective myopia correction and control. However, the incomplete understanding of its biomechanical mechanisms makes OK lens fitting rely heavily on clinician judgment, complicating accurate predictions of treatment outcomes. In this paper, we performed clinical experiments and numerical analysis to study corneal deformation modes and long-term changes in central corneal thickness. Clinical experiments were conducted on 194 Chinese myopic patients under OK treatment for 3 months. Based on the experimental data, a patient-specific computational biomechanical model for OK was established and validated. Specifically, the anisotropic mechanical properties of the cornea were incorporated into the model to describe the significant difference between its shear modulus(29.5 kPa) and tensile modulus(768.4 kPa). Additionally, a viscohyperelastic material model with a prolonged corneal relaxation time of 5.6 h was developed to capture the long-term deformation response. The results show that corneal thickness reduction in OK is primarily due to out-of-plane shear deformation,influenced by the cornea's low shear resistance. Modeling the extended corneal relaxation time is crucial for predicting long-term biomechanical responses. The computational model effectively captures long-term changes in central corneal thickness, potentially improving OK lens fitting accuracy.

关键词： orthokeratology computational biomechanical model long-term viscoelasticity myopia correction

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聚乙烯基复合材料的制备及阻燃耐水性能研究

塑料科技 2021年第6期49卷 37-41页

作者：杨世金广西安全工程职业技术学院广西南宁530100

以三氟丙基羟基聚硅氧烷改性的聚磷酸铵、自制的成炭剂(CA)为主要原料制备新型高效耐水膨胀阻燃剂,应用于聚乙烯阻燃性能研究。研究改性前后,聚磷酸铵对膨胀阻燃聚乙烯材料性能的影响。结果表明:三氟丙基羟基聚硅氧烷改性的聚磷酸铵水... 详细信息

以三氟丙基羟基聚硅氧烷改性的聚磷酸铵、自制的成炭剂(CA)为主要原料制备新型高效耐水膨胀阻燃剂,应用于聚乙烯阻燃性能研究。研究改性前后,聚磷酸铵对膨胀阻燃聚乙烯材料性能的影响。结果表明:三氟丙基羟基聚硅氧烷改性的聚磷酸铵水溶性明显降低。在聚乙烯中加入改性的聚磷酸铵的膨胀阻燃剂(PE/M-IFR),当阻燃剂添加量为30%时,70℃水中浸泡168 h后,1.6 mm样条垂直燃烧性能能够达到V-0级;在25℃下浸泡24 h,90℃水煮6 h后,1.6 mm样片的体积电阻率下降很小,材料的绝缘性更好。改性后材料的力学性能具有一定提高,最大热释放速率和总热释放更低,PE/M-IFR相容性更好,炭层更加致密。

关键词：三氟丙基羟基聚硅氧烷聚磷酸铵耐水性阻燃性能

船公司“利他偏好”与航运供应链上的纵向合作

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中国管理科学 2023年第11期31卷 195-207页

作者：李剑史金阳姜宝中国海洋大学经济学院山东青岛266100

在大幅波动的世界航运市场上,营销投入和需求波动是航运供应链上船公司与船代公司共同面对的双重成本压力。从而也给船公司以保证市场份额和竞争力为目的,而对船代公司采取“利他”行为提供了可能环境。本文构建了船公司与船代公司组成... 详细信息

在大幅波动的世界航运市场上,营销投入和需求波动是航运供应链上船公司与船代公司共同面对的双重成本压力。从而也给船公司以保证市场份额和竞争力为目的,而对船代公司采取“利他”行为提供了可能环境。本文构建了船公司与船代公司组成的风险厌恶型航运供应链,运用Stackelberg博弈模型,分析船公司的“利他偏好”行为对航运市场各方决策行为以及航运供应链纵向合作的影响。研究发现:(1)船公司的“利他偏好”会激励船代公司加大营销投入、拓展市场需求,从而提高航运供应链整体收益和竞争力;(2)虽然效果不及“纵向联盟”,但船公司的“利他偏好”可以加强航运供应链的纵向合作;(3)收益共享成本共担契约可以实现风险厌恶型航运供应链的契约协调,提高航运供应链整体利润和稳定性;(4)船公司的“利他偏好”可以提高收益共享成本共担契约决策的柔性,更有利于强化航运供应链上纵向合作的稳定性。

关键词：航运供应链船公司利他偏好契约协调风险厌恶

Mechanical Properties of Railway High-strength Manufactured Sand Concrete: Typical Lithology, Stone Powder Content and Strength Grade

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Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 194-203页

作者： WANG Zhen LI Huajian HUANG Fali yang Zhiqiang WEN Jiaxin shi Henan Railway Engineering Research Institute China Academy of Railway Science Corporation LimitedBeijing 100081China State Key Laboratory for Track Technology of High-Speed Railway Beijing 100081China

In order to achieve the large-scale application of manufactured sand in railway high-strength concrete structure,a series of high-strength manufactured sand concrete(HMC)are prepared by taking the manufactured sand lithology(tuff,limestone,basalt,granite),stone powder content(0,5%,10%,15%)and concrete strength grade(C60,C80,C100)as *** evolution of mechanical properties of HMC and the correlation between cubic compressive strength and other mechanical properties are *** to river sand,manufactured sand enhances the cubic compressive strength,axial compressive strength and elastic modulus of concrete,while its potential microcracks weaken the flexural strength and splitting tensile strength of *** powder content displays both positive and negative effects on mechanical properties of HMC,and the stone powder content is suggested to be less than 10%.The empirical formulas between cubic compressive strength and other mechanical properties are proposed.

关键词： manufactured sand concrete railway mechanical property lithology stone powder content

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一种新的用于跨领域推荐的迁移学习模型

计算机学报 2017年第10期40卷 2367-2380页

作者：王俊李石君杨莎金红余伟软件工程国家重点实验室武汉大学计算机学院武汉430072 汉口学院计算机科学与技术学院武汉430212

协同过滤是一种简单常用的推荐方法,但是当目标数据非常稀疏时,其性能会严重退化,借助与目标数据跨域关联的辅助数据进行跨领域推荐是解决此问题的一种有效途径.已有的跨领域推荐模型大多假设不同领域完全共享一个评分模式,忽略了领域... 详细信息

协同过滤是一种简单常用的推荐方法,但是当目标数据非常稀疏时,其性能会严重退化,借助与目标数据跨域关联的辅助数据进行跨领域推荐是解决此问题的一种有效途径.已有的跨领域推荐模型大多假设不同领域完全共享一个评分模式,忽略了领域特有评分模式,可能导致推荐性能退化.此外,许多模型基于单一桥梁迁移跨领域信息,正迁移不足.特别是在考虑领域特有被评分模式的前提下,据作者所知目前还没有模型利用项目的共享被评分模式进行跨领域推荐.因此,该文提出一种新的三元桥迁移学习模型,用于跨领域推荐.首先通过评分矩阵的集合分解提取用户的潜在因子和共享评分模式,以及项目的潜在因子和共享被评分模式,在此过程中考虑了领域特有模式,并对潜在因子施加相似性约束;然后利用潜在因子中的聚类信息构造邻接图;最后通过用户端和项目端的基于共享模式、潜在因子和邻接图的三元桥迁移学习联合预测缺失评分.在三个公开的真实数据集上进行的大量实验表明,该模型的推荐精度优于一些目前最先进的推荐模型.

关键词：迁移学习推荐协同过滤跨领域稀疏矩阵分解