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Cortical Bone Model with a Microcrack under Tensile Loading

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Wuhan University Journal of Natural Sciences 2022年第5期27卷 375-382页

作者： WANG Xu chen yaogeng DING Shenghu WANG Wenshuai LI Xing School of Mathematics and Statistics Ningxia UniversityYinchuan 750021NingxiaChina School of Science Ningxia Medical UniversityYinchuan 750004NingxiaChina

The fracture mechanics of cortical bone has received much attention in biomedical *** is a fundamental question how the material constants and the geometric parameters of the cortical bone affect the fracture behavior of the cortical *** this work,the plane problem for cortical bone with a microcrack located in the interstitial tissue under tensile loading was *** the solution for the continuously distributed edge dislocations as Green ’ s functions,the problem was formulated as singular integral equations with Cauchy *** numerical results suggest that a soft osteon promotes microcrack propagation,while a stiff osteon repels it,but the interaction effect between the microcrack and the osteon is limited near the *** study not only sheds light on the fracture mechanics behavior of cortical bone but also offers inspiration for the design of bioinspired materials in biomedical engineering.

关键词： cortical bone microcrack singular integral equation Cauchy kernel stress intensity factor

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含裂纹半无限大功能梯度材料的接触问题

宁夏大学学报（自然科学版） 2009年第3期30卷 232-235页

作者：陈耀庚李星宁夏师范学院数学与计算机科学学院宁夏固原756000 宁夏大学数学与计算机学院宁夏银川750021

研究了含裂纹半无限大功能梯度材料的接触问题.假设材料的剪切模量沿y轴呈指数规律变化,利用Fou-rier变换将问题转化为关于未知位错密度函数的奇异积分方程,并把位错密度函数表示为Chebyshev多项式,从而将奇异积分方程转化为线性代数方... 详细信息

研究了含裂纹半无限大功能梯度材料的接触问题.假设材料的剪切模量沿y轴呈指数规律变化,利用Fou-rier变换将问题转化为关于未知位错密度函数的奇异积分方程,并把位错密度函数表示为Chebyshev多项式,从而将奇异积分方程转化为线性代数方程组进行配点数值求解.最后分析了梯度材料非均匀参数、摩擦系数、裂纹长度以及裂纹距刚性压头中心的水平距离对应力强度因子的影响.

关键词：赫兹接触功能梯度材料裂纹问题奇异积分方程应力强度因子

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涂料中重金属元素的危害及检测方法的概述

福建分析测试 2005年第3期14卷 2247-2248页

作者：陈尧根谢灵杨浙江海盐县产品质量监督检验所

本文结合国家相关强制性标准规定,对涂料中重金属的来源、及其对人体的危害和目前对各种重金属的检测方法进行概述。

关键词：检测方法重金属元素危害涂料标准规定强制性

基于增强回归树模型评估宁夏回族自治区气象因素和大气污染物对流行性腮腺炎发病影响

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中国公共卫生 2024年第10期40卷 1183-1188页

作者：刘祥龙陈琳琳余佳玉龚瑞陈耀庚赵瑜宁夏医科大学公共卫生学院流行病和卫生统计学系银川750004 宁夏环境因素与慢性病控制重点实验室银川750004 宁夏疾病预防控制中心传染病与预防控制科银川750004 宁夏医科大学医学信息与工程学院银川750004

目的评估宁夏回族自治区气象因素和大气污染物对流行性腮腺炎发病的影响,为流行性腮腺炎的早期预防和反应系统的建设提供参考依据。方法收集宁夏回族自治区2015年1月1日—2019年12月31日流行性腮腺炎的发病数据以及每日气象和大气污染... 详细信息

目的评估宁夏回族自治区气象因素和大气污染物对流行性腮腺炎发病的影响,为流行性腮腺炎的早期预防和反应系统的建设提供参考依据。方法收集宁夏回族自治区2015年1月1日—2019年12月31日流行性腮腺炎的发病数据以及每日气象和大气污染物数据,应用增强回归树(BRT)模型来确定最能解释流行性腮腺炎新发病例的气象因素和大气污染物的最佳滞后,并评估该地区气象因素和大气污染物对流行性腮腺炎发病的影响。结果宁夏回族自治区2015—2019年流行性腮腺炎新发病例数为6660例,其中男性3936例(59.1%),女性2724例(40.9%);年龄15岁893例(13.4%)。BRT模型验证结果显示,滞后7 d时模型具有最大的训练集受试者工作特征曲线下面积(AUC)值为0.915、测试集AUC值为0.717、标准误为0.027,宁夏回族自治区1周前气象因素和大气污染物对流行性腮腺炎新发病例变化的解释作用最大。BRT模型分析结果显示,日均气温对流行性腮腺炎发病的相对重要性最大为26.36%,其次为日均相对湿度,相对重要性为13.90%;日均气温–3℃~23℃和日均相对湿度>40%为流行性腮腺炎发病风险增加的原因;较高的日均气压和日均风速对流行性腮腺炎的发病具有抑制作用;空气中臭氧(O_(3))浓度较低时对流行性腮腺炎的发病具有促进作用;空气中二氧化硫(SO_(2))浓度<100μg/m^(3)时对流行性腮腺炎的发病具有促进作用,浓度≥100μg/m^(3)则转变为抑制作用;较低浓度的一氧化碳(CO)、二氧化氮(NO_(2))、细颗粒物(PM_(2.5))和可吸入颗粒物(PM_(10))均对流行性腮腺炎的发病具有促进作用。结论宁夏回族自治区日均气温、日均相对湿度、日均气压、日均风速等气象因素以及O_(3)、SO_(2)、CO、NO_(2)、PM_(2.5)、PM_(10)等大气污染物在一定范围内对流行性腮腺炎的发病均具有显著促进作用。

关键词：流行性腮腺炎发病气象因素大气污染物影响增强回归树(BRT)模型评估

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弹性材料夹杂含裂纹梯度材料的接触问题

宁夏师范学院学报 2009年第3期30卷 16-21页

作者：陈耀庚杨晓春宁夏师范学院数学与计算机科学学院宁夏固原756000 大连海事大学数学系辽宁大连116023

研究弹性材料夹杂含裂纹功能梯度材料的接触问题.利用Fourier积分变换,将问题转化为关于未知位错密度函数的奇异积分方程,再用配点法对奇异积分方程进行数值求解.获得了裂纹尖端标准应力强度因子.数值结果显示了标准应力强度因子与梯度... 详细信息

研究弹性材料夹杂含裂纹功能梯度材料的接触问题.利用Fourier积分变换,将问题转化为关于未知位错密度函数的奇异积分方程,再用配点法对奇异积分方程进行数值求解.获得了裂纹尖端标准应力强度因子.数值结果显示了标准应力强度因子与梯度材料非均匀参数、摩擦系数、裂纹长度以及裂纹距刚性压头中心水平距离的关系.

关键词：接触问题功能梯度材料裂纹

Research progress on secondary formation,photosensitive reaction mechanism and human health effects of chromophoric brown carbon

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Journal of Environmental Sciences 2025年第5期151卷 310-330页

作者： Baihang chen Jiangyao chen Guiying Li Taicheng An Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and HealthInstitute of Environmental Health and Pollution ControlGuangdong University of TechnologyGuangzhou 510006China Guangdong Technology Research Center for Photocatalytic Technology Integration and Equipment Engineering Guangzhou Key Laboratory of Environmental Catalysis and Pollution ControlSchool of Environmental Science and EngineeringGuangdong University of TechnologyGuangzhou 510006China

Brown carbon(BrC)has attracted widespread attention because of its strong absorption of solar radiation in the ultraviolet-visible wavelength range,which causes adverse impacts on human ***,BrC was a physically defined class of ***,current research has gradually shifted towards the identification of its chemical groups,because its light-absorbing capability,chemical properties and health effects mainly depend on the chemical composition of its ***,this review mainly focuses on the chemical understanding of BrC based on chromophores,and the secondary formation mechanism of chromophores,photosensitized reactions,and human health effects of BrC were detailly ***,BrC chromophores are divided into five categories:nitrogen-heterocycles,nitrogen-chain,aromatic species,oligomers and sulfur-containing organic *** chromophore precursor species exhibit variations,and their formation mechanisms are also ***,BrC can trigger the production of secondary organic aerosol(SOA)precursors or cause SOA growth because BrC is an important component of light-absorbing particles formed during incomplete combustion of biomass and fossil fuels,potentially exerting adverse effects on human ***,developing sufficiently separated methods for BrC and refining algorithms and machine learning can lead to a more effective understanding of the chemical composition of chromophores,thus enabling better evaluation of the atmospheric effects and health impacts of *** all,this review provides new insights into the categories of BrC chromophores and new advance in secondary formation mechanisms,photosensitized reactions,and human health effects on the basis of chemical structures.

关键词： Brown carbon Constituent characteristics Secondary formation mechanism Photosensitive Human health effects

Halogen composition and heterogeneity in the continental lithospheric mantle

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Science China Earth Sciences 2025年第1期68卷 310-314页

作者： Chunfei chen State Key Laboratory of Geological Processes and Mineral Resources School of Earth SciencesChina University of GeosciencesWuhan430074China

*** Halogens,including fluorine(F),chlorine(Cl),bromine(Br),and iodine(I),are highly mobile and water-soluble elements that can become significantly enriched in melts and *** fluids and melts,halogens react with nearly all metals and readily form complexes with metal cations,significantly influencing the distribution of metal elements between different ***,halogens play a crucial role in the migration,enrichment,and mineralization of key metals in the lithosphere(Weis et al.,2012;Liu et al.,2024).

关键词： metals fluorine elements

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Cyano migration-mediated radical-polar crossover cyclopropanation

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Science China Chemistry 2025年第1期68卷 241-248页

作者： Ziqiang Wang Yasu chen Jie Li chen Zhu Key Laboratory of Organic Synthesis of Jiangsu Province College of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China Frontiers Science Center for Transformative Molecules Zhangjiang Institute for Advanced Study and Shanghai Key Laboratory for Molecular Engineering of Chiral DrugsShanghai Jiao Tong UniversityShanghai 200240China

We report a novel cyano migration-mediated radical-polar crossover process,whereby both the sulfonylcyanation of aliphatic alkenes and the formation of cyclopropanes are concurrently *** transformation yields a diverse array of multisubstituted cyclopropanes under mild photocatalytic *** studies elucidate that the reaction proceeds via intramolecular nucleophilic substitution,leading to the formation of the cyclopropane derivatives.

关键词： cyclopropanation cyano migration radical-polar crossover radical reactions

Mechanical properties and flow stress constitutive relationship of Ti–6Al–4V alloy with equiaxed microstructure at cryogenic temperatures

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Chinese Journal of Aeronautics 2025年第1期38卷 365-379页

作者： Jingwen HU Xun chen Yashun WANG chen YANG College of Intelligence Science and Technology National University of Defense TechnologyChangsha 410073China Laboratory of Science and Technology on Integrated Logistics Support National University of Defense TechnologyChangsha 410073China

This paper investigates the uniaxial tensile mechanical properties and flow behavior of Ti-6Al-4V alloys with equiaxed microstructure at cryogenic temperatures ranging from 77 K to298 K and strain rates from 10^(-4)/s to 10^(-2)/*** electron microscopy is utilized to analyze the fracture morphology,aiming to reveal the fracture behavior at various *** applicability of the Zener-Hollomon parameter and the Johnson-Cook model in describing the flow stress of Ti-6Al-4V at cryogenic temperatures is ***,a constitutive relationship modeling method based on the variational recurrent networks is *** test results show a significant increase in the strength of equiaxed Ti-6Al-4V alloy under cryogenic conditions while the plastic deformation process is ***,the fracture analysis indicates that even at 77 K,the fracture process is still dominated by ductile fracture,and brittle fracture does not occur within the range of 77 K to 298 *** fitting results validate the performance of the Zener-Hollomon parameter and the Johnson-Cook model in describing the deformation flow stress of Ti-6Al-4V alloy at cryogenic *** results also indicate that the proposed constitutive relationship modeling method based on the variational recurrent network performs better,making it a potential method for widespread applications.

关键词： Titanium alloys Mechanical properties Cryogenics Fracture testing Flow behavior