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激光粉末床熔融成形件的翘曲变形监测

中国激光 2024年第16期51卷 211-219页

作者：陈锦堂张凯刘婷婷邹志永李建森韦辉亮廖文和南京理工大学机械工程学院江苏南京210094

在激光粉末床熔融(LPBF)成形过程中,存在由热应力引起的翘曲变形,严重影响零件精度与性能。为了探究熔池辐射光信号与LPBF工艺中的翘曲变形过程的关联关系,为基于熔池辐射光采集的翘曲缺陷监测提供支持,设置了一组实验,成形了翘曲与非... 详细信息

在激光粉末床熔融(LPBF)成形过程中,存在由热应力引起的翘曲变形,严重影响零件精度与性能。为了探究熔池辐射光信号与LPBF工艺中的翘曲变形过程的关联关系,为基于熔池辐射光采集的翘曲缺陷监测提供支持,设置了一组实验,成形了翘曲与非翘曲试样,基于统计学方法分析了翘曲与未翘曲试样成形过程中熔池辐射光信号的特性。结果表明,未翘曲变形试样的光强分布较为均匀,无明显梯度,而翘曲变形试样在翘曲区域出现了明显的光强下降。对于翘曲变形的试样,在悬垂层变形尚未发生时,区域光强均值存在较大极差。翘曲试样与未翘曲试样的光强值层间演化趋势不同。随着成形层数的增加,悬垂结构对光强信号的影响逐渐减小,第5层后光强趋于稳定。

关键词：激光技术激光粉末床熔融翘曲变形过程监测熔池辐射光

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中国学龄儿童心血管健康状况评价

中国学校卫生 2024年第1期45卷 30-35页

作者：王西婕邹志勇董彦会董彬马军梁万年清华大学万科公共卫生与健康学院北京100190 清华大学健康中国研究院北京大学儿童青少年卫生研究所

目的了解中国学龄儿童心血管健康状况,为促进中国学龄儿童的心血管健康提供参考依据。方法数据来源于2013年在中国7省份开展的、具有全国代表性的多中心横断面研究,其原始研究采用多阶段整群抽样方法,本研究纳入其中健康行为和健康结局... 详细信息

目的了解中国学龄儿童心血管健康状况,为促进中国学龄儿童的心血管健康提供参考依据。方法数据来源于2013年在中国7省份开展的、具有全国代表性的多中心横断面研究,其原始研究采用多阶段整群抽样方法,本研究纳入其中健康行为和健康结局指标齐全的10326名5~19岁儿童。使用美国心脏协会“生活八要素”(LE 8)指标评价中国学龄儿童的整体心血管健康状况,健康行为指标包括膳食、体力活动、烟草暴露和睡眠健康;健康结局指标包括体质量指数(BMI)、空腹血糖、血脂和血压。结果男童平均LE 8为73.3(IQR=14.4)分,女童为73.4(IQR=13.5)分。线性回归分析结果显示,与≤9岁组相比,13~15岁组健康行为得分最低,男童β值为-7.73(95%CI=-8.35~-7.12,P<0.01),女童β值为-9.15(95%CI=-9.83~-8.48,P<0.01);≥16岁组健康结局得分最低,男童β值为-7.85(95%CI=-9.07~-6.63,P<0.01),女童β值为-6.11(95%CI=-7.12~-5.09,P<0.01)。结论中国学龄儿童的心血管健康水平处于一般水平。LE 8指标不同群体间存在很大差异,需要采取有针对性的干预策略,改善学龄儿童心血管健康。

关键词：心血管系统美国心脏协会回归分析儿童

中国三省市大学生“躺平”行为现状及其与抑郁症状的关联

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中国学校卫生 2024年第6期45卷 844-848,853页

作者：马声王欢王晓芳卢金逵王良君胡翼飞于晓冉宋逸邹志勇北京大学公共卫生学院/北京大学儿童青少年卫生研究所北京100191 辽阳市教育招生考试委员会办公室卫生保健科江西省上饶师范学院体育学院锦州医科大学公共卫生学院首都医科大学公共卫生学院

目的了解中国高校大学生“躺平”行为现状,并分析其与抑郁症状的关联,为促进青少年身心健康发展提供科学依据。方法2023年7—10月,在江西省、辽宁省和北京市通过方便抽样方法分别选择3所高校,在校内发放问卷星链接,采用自编问卷获得大... 详细信息

目的了解中国高校大学生“躺平”行为现状,并分析其与抑郁症状的关联,为促进青少年身心健康发展提供科学依据。方法2023年7—10月,在江西省、辽宁省和北京市通过方便抽样方法分别选择3所高校,在校内发放问卷星链接,采用自编问卷获得大学生基本信息与“躺平”行为表现,采用患者健康问卷(PHQ-9)筛查抑郁症状大学生,共获得有效问卷4225份。采用χ^(2)检验比较不同人口学特征大学生“躺平”行为的报告率,采用有序Logistic回归分析不同“躺平”行为表现与抑郁症状之间的关联,并采用Z检验评估关联程度的差异。结果大学生学业“躺平”、生活“躺平”和社交“躺平”的报告率分别为32.7%,17.8%和17.5%,其中6.7%的大学生同时具有3种“躺平”行为。在同时具有3种“躺平”行为的大学生中,无、轻度、中度及以上抑郁症状的构成比分别为9.9%,30.5%和59.6%。有序Logistic回归分析结果显示,有3种“躺平”行为的学生易发生轻度、中度及以上抑郁症状[OR值(95%CI)分别为2.49(1.60~3.87),7.69(5.01~11.79),P值均<0.01]。结论大学生学业“躺平”行为最为普遍,学业、生活和社交“躺平”行为与抑郁症状均呈正相关。应重视大学生“躺平”行为与抑郁等心理健康状况,促进大学生身心健康发展。

关键词：躺平抑郁精神卫生回归分析学生

Changing profiles of cardiovascular disease and risk factors in China:a secondary analysis for the Global Burden of Disease Study 2019

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Chinese Medical Journal 2023年第20期136卷 2431-2441页

作者： Huan Wang Hao Zhang zhiyong zou Institute of Child and Adolescent Health School of Public HealthPeking UniversityNational Health Commission Key Laboratory of Reproductive HealthBeijing 100191China Heart Center and Shanghai Institute of Pediatric Congenital Heart Disease Shanghai Children’s Medical CenterNational Children’s Medical CenterShanghai Jiaotong University School of MedicineShanghai 200127China

Background:Understanding the changing profiles of cardiovascular disease(CVD)and modifiable risk factors is essential for CVD prevention and *** aimed to report the comprehensive trends in CVD and risk factors in China from 1990 to ***:Data on the incidence,death,and disability-adjusted life years(DALYs)of total CVD and its 11 subtypes for China were obtained from the Global Burden of Disease Study *** CVD burden attributable to 12 risk factors was also retrieved.A secondary analysis was conducted to summarize the leading causes of CVD burden and attributable risk ***:From 1990 to 2019,the number of CVD incidence,death,and DALYs considerably increased by 132.8%,89.1%,and 52.6%,***,ischemic heart disease,and hypertensive heart disease accounted for over 95.0%of CVD deaths in 2019 and remained the top three causes during the past 30 *** 1990 and 2019,the age-standardized rate of stroke decreased significantly(percentage of decreased incidence:-9.3%;death:-39.8%;DALYs:-41.6%),while the rate of ischemic heart disease increased(percentage of increased incidence:11.5%;death:17.6%;DALYs:2.2%).High systolic blood pressure,unhealthy diet,tobacco,and air pollution continued to be the major contributors to CVD deaths and DALYs(attributing to over 70%of the CVD burden),and the high body mass index(BMI)-associated CVD burden had the largest increase between 1990 and ***:The significant increases in the number of CVD incident cases,deaths,and DALYs suggest that the CVD burden is still a *** strategies and policies are needed to maintain promising progress in stroke and to reduce the escalating burden of ischemic heart *** CVD burden attributable to risk factors has not yet made adequate achievements;even worse,high BMI has contributed to the increasing CVD burden.

关键词： Cardiovascular disease Stroke Ischemic heart disease Risk factors Global Burden of Disease Hypertensive heart disease

Comparison of time trends in the incidence of primary liver cancer between China and the United States: an age-period-cohort analysis of the Global Burden of Disease 2019

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Chinese Medical Journal 2022年第17期135卷 2035-2042页

作者： zhiyong zou Zuofeng Zhang Ce Lu Hui Wang Iinstitute of Child and Adolescent Health School of Public HealthPeking University Health Science CenterBeijing 100191China Department of Epidemiology Fielding School of Public HealthUniversity of CaliforniaLos AngelesCAUSA Department of Epidemiology School of Public HealthNanjing Medical UniversityNanjngJjiangsu 21161China Department of Maternal and Child Health School of Public HealthPeking University Health Science CenterBeijing 100191China

Background::China and the United States(US)ranked first and third in terms of new liver cancer cases and deaths globally in ***,a comprehensive assessment of trends in the incidence of primary liver cancer with four major etiological factors between China and the US during the past 30 years with age-period-cohort(APC)analyses is ***::Data were obtained from the Global Burden of Disease 2019,and period/cohort relative risks were estimated by APC modeling from 1990 to ***::In 2019,there were 211,000 new liver cancer cases in China and 28,000 in the US,accounting for 39.4%and 5.2%of global liver cancer cases,*** China,the age-standardized incidence rate(ASIR)consecutively decreased before 2005 but increased slightly since then,whereas the ASIR continuously increased in the *** the four etiological factors of liver cancer,the fastest reduction in incidence was observed in hepatitis B virus-related liver cancer among Chinese women,and the fastest increase was in nonalcoholic steatosis hepatitis(NASH)-related liver cancer among American *** greatest reduction in the incidence of liver cancer was observed at the age of 53 years in Chinese men(-5.2%/year)and 33 years in Chinese women(-6.6%/year),while it peaked at 58 years old in both American men and women(4.5%/year vs.2.8%/year).Furthermore,the period risks of alcohol-and NASH-related liver cancer among Chinese men have been elevated since ***,leveled-off period risks were observed in hepatitis C viral-related liver cancer in both American men and ***::Currently,both viral and lifestyle factors have been and will continue to play an important role in the time trends of liver cancer in both *** tailored and efficient preventive strategies should be designed to target both viral and lifestyle factors to prevent and control liver cancer.

关键词： Alcohol use-related liver cancer China Global Burden of Disease Hepatitis Hepatitis B virus Hepatitis C Incidence Liver neoplasms Life Style Middle aged Non-alcoholic fatty liverdisease United States

A Dual-Cluster-Head Based Medium Access Control for Large-Scale UAV Ad-Hoc Networks

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China Communications 2024年第5期21卷 123-136页

作者： Zhao Xinru Wei Zhiqing zou Yingying Ma Hao Cui Yanpeng Feng zhiyong Key Laboratory of Universal Wireless Communications Ministry of EducationSchool of Information and Communication EngineeringBeijing University of Posts and TelecommunicationsBeijing100876China

Unmanned Aerial Vehicle(UAV)ad hoc network has achieved significant growth for its flexibility,extensibility,and high deployability in recent *** application of clustering scheme for UAV ad hoc network is imperative to enhance the performance of throughput and energy *** conventional clustering scheme,a single cluster head(CH)is always assigned in each ***,this method has some weaknesses such as overload and premature death of CH when the number of UAVs *** order to solve this problem,we propose a dual-cluster-head based medium access control(DCHMAC)scheme for large-scale UAV *** DCHMAC,two CHs are elected to manage resource allocation and data forwarding ***,two CHs work on different *** of CH is used for intra-cluster communication and the other one is for inter-cluster communication.A Markov chain model is developed to analyse the throughput of the *** result shows that compared with FM-MAC(flying ad hoc networks multi-channel MAC,FM-MAC),DCHMAC improves the throughput by approximately 20%~50%and prolongs the network lifetime by approximately 40%.

关键词： dual cluster head medium access control UAV swarm

A Fuzzy Control Based Intelligent Control System for Flower Greenhouse

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International Journal of Technology Management 2015年第1期 80-83页

作者： zou zhiyong Zhou Man College of Mechanical and Electronic Engineering Sichuan Agricultural University Ya'an Sichuan Province 625014 China

In order to realize intelligent control of flower greenhouse＇ s parameters of atmospheric temperature and humidity, lighting intensity, CO2 concentration and soil water content, it carries out design with ZigBee network, embedded controller and intelligent fuzzy control algorithm as core. With advantages of high precision and stability, the design of sensor circuit mainly employs digital module sensors. In order to save energy, the sensor circuit is controlled by relay switch to work at the proper time. The gateway node is designed by employing high performance 32-digit embedded controller and WinCE6.0 embedded OS is self customized. And embedded SQlite database is realized on WinCE6.0 for effectively managing data. The closed loop control is realized by employing fuzzy control algorithm and the test result shows that the deviation of atmospheric temperature is controlled within ± 0.5° C, the deviation of illumination intensity is controlled within ± 283 LUX, the deviation of CO2 concentration is controlled within ± 24 PPM, the deviation of atmospheric humidity is controlled within ± 13% and that of soil water content is controlled within ± 0.9%, thus all parameters fully meet practical requirements of flower greenhouse.

关键词： Flower greenhouse ZigBee network Sensor Embedded controller Fuzzy control Intelligent control.

Design of an Expert Control System for Biogas Fermentation Process

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International Journal of Technology Management 2015年第2期 53-55页

作者： Zhou Man zou zhiyong School of Water Resources and Hydropower Sichuan Agricultural University Ya'an Sichuan Province 625014 China

Controlling the biogas fermentation process is the key for maintaining stable operation of biogas system and increasing gas yield. Aiming at features of biogas fermentation process and difficulties of control, a practical control scheme is proposed combining the abundant experience of biogas experts. And it discussed the structural design and hardware configuration of the expert control system, established the database and role base, and designed the control strategy of production system inference. The design scheme with ZigBee and PDA technology as core is employed so as to solve problems of environmental factor detection and data transfer management. The test result shows that the deviation of temperature is controlled within ± 0.9℃, the deviation of pH is controlled within ±0.3, the deviation of oxidation-reduction potential is controlled within ±30mV, the deviation of gas production is controlled within ± 9mL and that of methane concentration is controlled within ±4.5%. This system is easily expandable and applicable to biogas engineering at various scales.

关键词： Anaerobic fermentation Expert system Intelligent control ZigBee network Sensor

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新建桩基对非连续模型下的盾构管片影响研究

国防交通工程与技术 2024年第2期22卷 11-15,31页

作者：余建伟董昊威唐磊李昊明邹志勇侯建林北京铁城建设监理有限责任公司北京100855 中铁北京工程局集团城市轨道交通工程有限公司安徽合肥230088 西南科技大学土木工程与建筑学院四川绵阳621010

基于非线性接触理论,在管片间简化设置挤压与摩擦关系模拟管片接头结构,依据贵阳市清溪路—花冠路节点改造工程,建立了非连续接触双线盾构平面应变模型,在盾构隧道两线内侧桩基净距不变的情况下,通过改变两线外侧桩基净距,对桩基施工与... 详细信息

基于非线性接触理论,在管片间简化设置挤压与摩擦关系模拟管片接头结构,依据贵阳市清溪路—花冠路节点改造工程,建立了非连续接触双线盾构平面应变模型,在盾构隧道两线内侧桩基净距不变的情况下,通过改变两线外侧桩基净距,对桩基施工与承载阶段对既有盾构隧道管片的影响进行了分析。研究结果表明:使用简化的非连续模型能够模拟出管片间的变形错动。桩基承载阶段,竖向与水平的最大变形分别在拱顶与拱腰处。管片间的法向压力在桩基施工时先减小后增加,在桩基承载后达到最大;管片间最大与最小主应力随桩基净距的增加而减小;管片接头处存在应力集中现象,表现为近两线外侧桩基处的拱腰受拉压,且应力值最大,拱顶、拱底、两侧拱腰仍然是应力分布的最主要区域。桩基施工阶段是管片间剪应力增加的主要阶段,当净距大于3.0 m后对剪应力影响较小。实际施工时建议桩基净距保持在3.0 m及以上的距离。

关键词：盾构隧道管片接头桩基施工桩基承载变形拉压应力剪应力