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Modeling of environmental influence in structural health assessment for reinforced concrete buildings

Earthquake Engineering and Engineering Vibration 2010年第2期9卷 295-306页

作者： ka-Veng Yuen Sin-Chi Kuok Department of Civil and Environmental Engineering Univeristy of Macao

One branch of structural health monitoring (SHM) utilizes dynamic response measurements to assess the structural integrity of civil infrastructures. In particular,modal frequency is a widely adopted indicator for structural damage since its square is proportional to structural stiffness. However,it has been demonstrated in various SHM projects that this indicator is substantially affected by fluctuating environmental conditions. In order to provide reliable and consistent information on the health status of the monitored structures,it is necessary to develop a method to filter this interference. This study attempts to model and quantify the environmental influence on the modal frequencies of reinforced concrete buildings. Daily structural response measurements of a twenty-two story reinforced concrete building were collected and analyzed over a one-year period. The Bayesian spectral density approach was utilized to identify the modal frequencies of this building and it was clearly seen that the temperature and humidity fluctuation induced notable variations. A mathematical model was developed to quantify the environmental effects and model complexity was taken into consideration. Based on a Timoshenko beam model,the full model class was constructed and other reduced-order model class candidates were obtained. Then,the Bayesian modal class selection approach was employed to select the one with the most suitable complexity. The proposed model successfully characterizes the environmental influence on the modal frequencies. Furthermore,the estimated uncertainty of the model parameters allows for assessment of the reliability of the prediction. This study not only improves the understanding about the monitored structure,but also establishes a systematic approach for reliable health assessment of reinforced concrete buildings.

关键词： Bayesian inference model selection reinforced concrete building structural health monitoring temperature and humidity effects Timoshenko beam

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优化高炉炉顶DCS设备在线监测自动控制

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冶金信息导刊 2024年第5期61卷 38-40页

作者：庞凯李锦龙河钢集团宣钢公司宣化075100

随着高炉系统的自动化运行率逐渐趋于完善,大大减少了岗位人员工艺流程操作步骤,因此降低设备故障率,提高系统自动化强度尤其重要。

关键词：高炉 DCS控制系统炉顶编码器

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老年胃溃疡出血患者再发出血的危险因素分析

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中国烧伤创疡杂志 2024年第1期36卷 62-65页

作者：卞卡张巍巍许昌市中心医院消化内科河南许昌461000 许昌市中心医院胃肠外科河南许昌461000

目的探讨分析老年胃溃疡出血患者再发出血的相关危险因素。方法选取2020年3月至2022年3月许昌市中心医院收治的140例老年胃溃疡出血患者作为研究对象,收集患者性别、年龄、发病部位、胃溃疡长径、出血活动度、是否为胃溃疡A1期、是否合... 详细信息

目的探讨分析老年胃溃疡出血患者再发出血的相关危险因素。方法选取2020年3月至2022年3月许昌市中心医院收治的140例老年胃溃疡出血患者作为研究对象,收集患者性别、年龄、发病部位、胃溃疡长径、出血活动度、是否为胃溃疡A1期、是否合并幽门螺杆菌(Hp)感染、有无吸烟史、有无饮酒史、合并其他慢性疾病种类(≤2种、>2种)、是否进行消化内镜治疗、是否长期使用非甾体抗炎药(NSAIDs)等资料,并根据患者止血成功后1个月内是否再发出血将患者分为发生组与未发生组。多因素Logistic回归分析老年胃溃疡出血患者再发出血的危险因素。结果140例老年胃溃疡出血患者均于止血成功后随访1个月,随访过程中21例(150%)患者再发出血,设为发生组;119例(850%)患者未再发出血,设为未发生组。单因素分析结果显示,发生组胃溃疡A1期、Hp感染、未进行消化内镜治疗、长期使用NSAIDs的患者比例均明显高于未发生组(χ^(2)=4269、7381、7580、11836,P=0039、0007、0006、0001);多因素Logistic回归分析结果显示,胃溃疡A1期、Hp感染、未进行消化内镜治疗、长期使用NSAIDs是老年胃溃疡出血患者再发出血的独立危险因素(95%CI为1039~9660、1909~58707、0059~0585、1880~18559,P=0043、0007、0004、0002)。结论胃溃疡A1期、Hp感染、未进行消化内镜治疗、长期使用NSAIDs是老年胃溃疡出血患者再发出血的独立危险因素,临床应根据患者具体情况制定针对性干预措施,以降低再出血发生风险。

关键词：胃溃疡出血老年再出血消化内镜治疗幽门螺杆菌非甾体抗炎药危险因素

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经支气管冷冻肺活检后按需手术肺活检对比即刻手术肺活检诊断间质性肺疾病(COLD研究):一项随机对照临床试验

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中华结核和呼吸杂志 2024年第9期47卷 826-826页

作者： kalverda ka Ninaber MK Wijmans L 阳胜朱娅琳肖奎不详中南大学湘雅二医院呼吸与危重症医学科中南大学呼吸疾病研究所湖南省呼吸与危重症疾病临床医学研究中心中南大学呼吸疾病诊疗中心长沙410000

背景:间质性肺疾病(ILD)的充分诊断对于临床决策和预后非常重要。大多数ILD患者可通过对临床和放射学数据的评估做出准确诊断,但还有相当一部分患者仍需进行肺活检。手术肺活检(SLB)是获取组织的最常用方法,但其发病率甚至死亡率都很高... 详细信息

背景:间质性肺疾病(ILD)的充分诊断对于临床决策和预后非常重要。大多数ILD患者可通过对临床和放射学数据的评估做出准确诊断,但还有相当一部分患者仍需进行肺活检。手术肺活检(SLB)是获取组织的最常用方法,但其发病率甚至死亡率都很高。最近,临床引入了经支气管冷冻肺活检,其不良反应较SLB少,但诊断率低于SLB。本研究旨在比较两种诊断策略:阶梯策略(经支气管冷冻肺活检,如果冷冻活检获得的信息不够,再进行SLB)与即刻SLB策略。方法:COLD研究是一项在荷兰6家医院开展的多中心、随机对照临床试验。该研究纳入了经多学科团队讨论评估有肺活检指征的ILD患者。以1∶1的比例将患者随机分配到阶梯策略或即刻SLB策略中,并从首次手术开始随访12周。本研究的治疗对患者、临床医生和病理学家均未设盲。主要研究终点是非预期的胸管引流,定义为经支气管冷冻肺活检后需要胸管引流,或SLB后胸管引流时间延长(>24 h)。次要研究终点是诊断率、住院时间、术后疼痛评分和严重不良事件,其中,严重不良事件包括研究期间患者出现死亡、危及患者生命、患者需再次入院或患者住院时长增加[经支气管镜检查超过2 d(1个夜晚),SLB超过4 d(3个夜晚)]。研究进行了改良的意向治疗分析。研究已在荷兰试验注册中心(NL7634)注册,现已结束。结果:在2019年4月8日至2021年10月24日期间,122例ILD患者接受了研究评估;55例患者被随机分配至阶梯组(n=28)或即刻SLB组(n=27);即刻SLB组有3例患者被排除。阶梯组的28例患者中有3例发生意外胸管引流(11%,95%CI:4%~27%),而即刻SLB组24例患者中有11例(46%,95%CI:2%~65%)在24 h内无法拔除胸管,绝对风险降低35%(11%~56%,P=0.0058)。在阶梯策略中,仅经支气管冷冻肺活检后的多学科团队诊断率为82%(64%~92%),在经支气管冷冻肺活检不确定后进行后续SLB时,诊断率增至89%(73%~96%)。在即刻SLB策略中,多学科团队的诊断率为88%(69%~97%)。阶梯组的总住院时间为1 d(IQR 1~1),而即刻SLB组为5 d(IQR 4~6)。阶梯组发生了1起(4%)严重不良事件,而即刻SLB组发生了12起(50%)严重不良事件。结论:在ILD诊断中,如果需要对肺组织进行评估,那么诊断策略应从经支气管冷冻肺活检开始,然后在经支气管冷冻肺活检不能得出诊断结论时进行SLB,这样似乎可显著减轻患者负担,缩短住院时间,且诊断率与即刻SLB相似。

关键词：间质性肺疾病支气管镜检查多学科团队患者负担病理学家肺活检临床决策诊断策略

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Optimal Design of Splitters Attached to Turbo Blower Impeller by RSM

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Journal of Thermal Science 2012年第3期21卷 215-222页

作者： Choon-Man Jang ka-Ram Choi Environmental Engineering Research Division Korea Institute of Construction Technology

This paper describes the optimization of the impeller having splitters for a turbo *** design variables,chord of splitter and pitch of splitter,are introduced to enhance the blower *** pressure and ef-ficiency are selected as an object function,and the optimization of the blower impeller is performed by a response surface method (RSM).Three-dimensional Navier-Stokes equations are introduced to analyze the internal flow of the blower and to find the value of the object function for each *** the shape optimization of the splitters attached to the impeller in the turbo blower,pressure and efficiency at the design flow condition are suc-cessively increased by 5.9 percent and 17.9 percent respectively based on the reference *** higher blower efficiency obtained by optimization of impeller having splitters is mainly caused by reducing the number of im-peller blades and optimal design of splitters in the blade passage while pressure increase keeps almost the same with the reference *** the object function of pressure,pressure increase is obtained at the design and off-design conditions while efficiency keeps higher compared to the reference *** enhancement of blow-er performance is due to the reduction of reverse and circulation flows in the blade passage.

关键词： Turbo Blower Splitter Numerical Simulation Optimal Design Pressure Response Surface Method

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A Registry-Based Observational Study on the Maternal and Fetal Outcomes of COVID-19 Patients in Hong Kong,China

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Maternal-Fetal Medicine 2024年第3期6卷 156-163页

作者： Hillary HY Leung Teresa WL Ma Florrie NY Yu Meliza CW Kong Tsz Kin Lo Pauline PL So Wing-Cheong Leung Wendy Shu ka Wang Cheung Sakita Moungmaithong Chi Chiu Wang Liona C.Poon Department of Obstetrics and Gynaecology The Chinese University of HongKongHong Kong 999077China Department of Obstetrics and Gynaecology Queen Elizabeth HospitalHong Kong 999077China Department of Obstetrics and Gynaecology United Christian HospitalHong Kong 999077China Department of Obstetrics and Gynaecology Princess Margaret HospitalHong Kong 999077China Department of Obstetrics and Gynaecology Tuen Mun HospitalHong Kong 999077China Department of Obstetrics and Gynaecology Kwong Wah HospitalHong Kong 999077China Department of Obstetrics and Gynaecology Pamela Youde Nethersole Eastern HospitalHong Kong 999077China Department of Obstetrics and Gynaecology Queen Mary HospitalHong Kong 999077China

Objective:To report the clinical maternal and fetal outcomes of pregnant women with coronavirus disease 2019(COVID-19),along with any associated pregnancy complications,in Hong Kong,China,and to assess the impact of COVID-19 vaccination on these ***:This prospective registry-based observational study included pregnant women who were recruited through convenient sampling and had a laboratory-confirmed severe acute respiratory syndrome coronavirus 2 infection with a cycle threshold(Ct)value result available on admission to eight local hospitals in Hong Kong,*** on clinical symptoms,laboratory results,medical treatments,delivery timing and mode,and pregnancy complications were extracted from the Hospital Authority’s electronic medical record ***,fetal,and pregnancy outcomes were compared between unvaccinated pregnant women with COVID-19 and those who had received at least one dose of COVID-19 vaccine before *** continuous variables and categorical variables were analyzed using the Mann-Whitney U test and the Pearson’s chi-squared test respectively.A P value less than 0.05 was considered statistically ***:A total of 164 pregnant women were included,of whom 78(47.56%)were ***-19 was diagnosed before 28 weeks’gestation in 30(18.29%),while 134(81.71%)were diagnosed at or after 28 weeks’***-two(37.80%)women received at least one dose of COVID-19 *** were no significant differences between vaccinated and unvaccinated groups in the time interval between COVID-19 diagnosis and delivery,the Ct value,and the gestational age at infection onset or delivery(P>0.05).The majority of women were symptomatic at diagnosis regardless of vaccination status 55(88.71%)in vaccinated group vs.78(76.47%)in unvaccinated group(P=0.052).Symptoms did not significantly differ between groups except for cough(62.90%vs.47.06%,P=0.049).The overall rate of severe COVID-19 in pregnant women was *** t

关键词： COVID-19 Maternal outcomes Fetal outcomes Pregnancy complications Severe COVID-19

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Coupled quantum molecular cavity optomechanics with surface plasmon enhancement

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Photonics Research 2017年第5期5卷 450-456页

作者： JIAN LIU ka-DI ZHU Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education) School of Physics and Astronomy Shanghai Jiao Tong University

Cavity optomechanics is applied to study the coupling behavior of interacting molecules in surface plasmon systems driven by two-color laser beams. Different from the traditional force–distance measurement, due to a resonant frequency shift or a peak splitting on the probe spectrum, we have proposed a convenient method to measure the van der Waals force strength and interaction energy via nonlinear spectroscopy. The minimum force value can reach approximately 10^(-15) N, which is 3 to 4 orders of magnitude smaller than the widely applied atomic force microscope(AFM). It is also shown that two adjacent molecules with similar chemical structures and nearly equal vibrational frequencies can be easily distinguished by the splitting of the transparency peak. Based on this coupled optomechanical system, we also conceptually design a tunable optical switch by van der Waals interaction. Our results will provide new approaches for understanding the complex and dynamic interactions inmolecule–plasmon systems.

关键词： Coupled quantum molecular cavity optomechanics with surface plasmon enhancement THz

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清水混凝土在桥梁施工中的应用研究

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工程建设与设计 2024年第6期 185-187页

作者：张卡叶腾飞中交一航局第二工程有限公司山东青岛266071

以具体工程为例,介绍了清水混凝土的特点,阐述了脚手架的搭设要点,对清水混凝土模板安装工艺进行了分析,并就清水混凝土浇筑、振捣、养生等施工技术措施展开了详细的研究,以提高桥梁工程中清水混凝土施工效率,确保桥梁工程整体施工质量... 详细信息

以具体工程为例,介绍了清水混凝土的特点,阐述了脚手架的搭设要点,对清水混凝土模板安装工艺进行了分析,并就清水混凝土浇筑、振捣、养生等施工技术措施展开了详细的研究,以提高桥梁工程中清水混凝土施工效率,确保桥梁工程整体施工质量,从而推进我国桥梁建筑工程可持续发展。

关键词：桥梁工程清水混凝土应用

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Building an e-Portfolio with a learning plan centric approach

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Journal of Zhejiang University-Science C(Computers and Electronics) 2012年第1期13卷 37-47页

作者： Lam-for KWOK ka-shing CHAN Department of Computer Science City University of Hong Kong

A portfolio records achievements in the personal growth process. A personal development e-Portfolio assists an individual in planning his/her development path and reflecting upon his/her own learning. In this article, we propose an approach to constructing a personal development portfolio. An abstract information model is presented to support such a portfolio. The information model is proposed based upon and according to IMS standards. The use of this approach is illustrated by way of a prototype e-Portfolio system. The usage scenario and limitations of such a portfolio are also discussed.

关键词： E-Portfolio Educational technology system Lifelong learning

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Microstructure and Property Relationships in Resistance Spot Weld between 7114 Interstitial Free Steel and 304 Austenitic Stainless Steel

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Journal of Materials Science & Technology 2006年第3期22卷 375-381页

作者： Ahmet Hasanba■o■lu Ramazan kaar Department of Metal Education karabük Technical Education Faculty Karabük 78100 Turkey

Due to the differences in physical, chemical and mechanical properties of the base metals, the resistance spot welding of dissimilar materials is generally more challenging than that of similar materials. The influence of the primary welding parameters affecting the heat input such as peak current on the morphology, microhardness, and tensile shear load bearing capacity of dissimilar welds between 304 grades austenitic and 7114 grade interstitial free steel has been investigated in this study. The optimum welding parameters producing maximum joint strength were established at a peak current of 9 ka, where the electrode force is kept 6×10^-5 Pa and weld time is kept constant 17 cycles, respectively. The primary cause of weakening the weldment is identified as the excessive grain growing region of heat affected zone （HAZ） in case of 7114 grade interstitial free steel.

关键词： Resistance spot weld Interstitial free steel Austenitic stainless steel

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