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Discontinuous mechanical behaviors of existing shield tunnel with stiffness reduction at longitudinal joints

《结构与土木工程前沿（英文）》 2023年 第17卷 第1期   页码 37-52 doi: 10.1007/s11709-022-0920-3

摘要： An analytical model is proposed to estimate the discontinuous mechanical behavior of an existing shield tunnel above a new tunnel. The existing shield tunnel is regarded as a Timoshenko beam with longitudinal joints. The opening and relative dislocation of the longitudinal joints can be calculated using Dirac delta functions. Compared with other approaches, our method yields results that are consistent with centrifugation test data. The effects of the stiffness reduction at the longitudinal joints (α and β), the shearing stiffness of the Timoshenko beam GA, and different additional pressure profiles on the responses of the shield tunnel are investigated. The results indicate that our proposed method is suitable for simulating the discontinuous mechanical behaviors of existing shield tunnels with longitudinal joints. The deformation and internal forces decrease as α, β, and GA increase. The bending moment and shear force are discontinuous despite slight discontinuities in the deflection, opening, and dislocation. The deflection curve is consistent with the additional pressure profile. Extensive opening, dislocation, and internal forces are induced at the location of mutation pressures. In addition, the joints allow rigid structures to behave flexibly in general, as well as allow flexible structures to exhibit locally rigid characteristics. Owing to the discontinuous characteristics, the internal forces and their abrupt changes at vulnerable sections must be monitored to ensure the structural safety of existing shield tunnels.

关键词： tunnel–soil interaction     discontinuous analysis     longitudinal joints     existing shield tunnel     Timoshenko beam     Dirac delta function    

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原子质量的相对论效应和应用

朱正和,傅依备,蒙大桥,唐永健

《中国工程科学》 2011年 第13卷 第1期   页码 21-24

摘要：

应用相对论理论(Dirac)来计算 C、O、S、Se、Te、Sm和Pu原子的相对论和非相对论的电子状态和能量，比较相对论和非相对论的能量差别后得到

关键词： Dirac理论     质量的相对论效应     钐和钚原子    

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An improved delta-star switching scheme for reactive power saving in three-phase induction motors

P. RAJA,N. KUMARESAN,M. SUBBIAH

《能源前沿（英文）》 2014年 第8卷 第3期   页码 364-370 doi: 10.1007/s11708-014-0324-8

摘要： It is proposed that a capacitor can be connected permanently across each phase winding of a three-phase induction motor along with the conventional delta-star switching, for further saving in VARh at reduced loads on the motor. The method of choosing a suitable value for the capacitor and the criteria to be adopted for calculating the power output at which the star to delta switching is to be made are also explained. The experimental results on a 3-phase, 4-pole, 415 V, 50 Hz, 3.3 kW induction motor verify the advantages in adding the capacitor to the phase winding of the motor. Compared to using only a single delta connected stator winding or a delta-star switching, the advantages of the proposed addition of a capacitor, are also demonstrated through a case study conducted on a 400 V, 250 kW motor. Any further improvement in grid side power factor can be achieved by employing a static synchronous compensator (STATCOM) of reduced VAR rating.

关键词： delta-star switching     induction motor     power factor     steady-state analysis    

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Energy internet in the Yangtze River Delta: opportunities, challenges, and suggestions

Zheng YAN, Jiayi HU

《能源前沿（英文）》 2018年 第12卷 第4期   页码 484-492 doi: 10.1007/s11708-018-0600-0

摘要：

Energy internet is an Internet of Things (IoT) based network, which combines the multi-energy flows and the information flows. In this review, the opportunities and the challenges posed to developing energy internet in the Yangtze River Delta are analyzed concerning detailed analysis of its advantages in various aspects and problems of its energy systems. Then the framework of energy internet in the Yangtze River Delta is constructed, according to which specific suggestions are also provided. This review is dedicated to helping the policy makers to draw the roadmap of future-oriented energy internet.

关键词： energy internet     opportunities     challenges     suggestions     the Yangtze River Delta    

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Long-term trends of fine particulate matter and chemical composition in the Pearl River Delta Economic

Xuemei WANG,Weihua CHEN,Duohong CHEN,Zhiyong WU,Qi Fan

《环境科学与工程前沿（英文）》 2016年 第10卷 第1期   页码 53-62 doi: 10.1007/s11783-014-0728-z

摘要： Understanding the trends in PM levels is essential for formulating clean air plans. This paper analyzes PM data from various published sources for the years 2000 to 2010 in the Pearl River Delta Economic Zone (PRDEZ). The long-term variation in PM mass concentration is analyzed. Results show that PM , organic carbon (OC), elemental carbon (EC), and show a similar trend, increasing before 2005 and then decreasing slightly. The annual average PM concentration ranges from 49.1 μg·m in 2000 to 64.3 μg·m in 2010, with a peak of 84.1 μg·m in 2004. None of these 11 years meets the new National Ambient Air Quality standard (NAAQS) for PM (35 μg·m ). Overall average concentrations of OC, EC, and are 13.0, 6.5, and 11.8 μg·m , respectively. and respectively have concentrations of 1.5 μg·m and 2.9 μg·m in 2000 and 6.4 μg·m and 5.3 μg·m in 2010, with a statistically significant average annual trend of+ 0.2 μg·m ·yr and+ 0.1 μg·m ·yr . In certain geographic regions, OC and EC contribute most of the PM , while in other regions secondary water-soluble ions are more important. In general, OC and are the dominant components of PM , contributing 20.6% and 18.6%, respectively. These results provide, for the first time, a better understanding of the long-term PM characteristics and trends, on a species-by-species basis, in the PRDEZ. The results indicate that PM abatement needs to prioritize secondary species.

关键词： long-term trends     fine particulate matter     chemical components     Pearl River Delta Economic Zone (PRDEZ)    

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attribution for mercury deposition with an updated atmospheric mercury emission inventory in the Pearl River Delta

Jiajun Liu, Long Wang, Yun Zhu, Che-Jen Lin, Carey Jang, Shuxiao Wang, Jia Xing, Bin Yu, Hui Xu, Yuzhou Pan

《环境科学与工程前沿（英文）》 2019年 第13卷 第1期 doi: 10.1007/s11783-019-1087-6

摘要：

Estimated anthropogenic Hg emission was 11.9 tons in Pearl River Delta for 2014.

Quantifying contributions of emission sources helps to provide control strategies.

More attentions should be paid to Hg deposition around the large point sources.

Power plant, industrial source and waste incinerator were priorities for control.

A coordinated regional Hg emission control was important for controlling pollution.

关键词： Emission inventory     Mercury deposition     Pearl River Delta (PRD)     Source attribution     Control strategy    

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Photochemical indicators of ozone sensitivity: application in the Pearl River Delta, China

Lyumeng Ye,Xuemei Wang,Shaofeng Fan,Weihua Chen,Ming Chang,Shengzhen Zhou,Zhiyong Wu,Qi Fan

《环境科学与工程前沿（英文）》 2016年 第10卷 第6期 doi: 10.1007/s11783-016-0887-1

摘要： The distribution of NO - and VOC-sensitive regimes in the PRD are identified. The effectiveness of six popular chemical indicators for discriminating O sensitivity regimes is evaluated. Threshold levels for HCHO/NO , H O /HNO , O /NO , O /NO , O /HNO were derived and verified. The indicators H O /HNO and H O /NO performed best and maintained relatively stable threshold levels. Surface O production has a highly nonlinear relationship with its precursors. The spatial and temporal heterogeneity of O -NO -VOC-sensitivity regimes complicates the control- decision making. In this paper, the indicator method was used to establish the relationship between O sensitivity and assessment indicators. Six popular ratios indicating ozone-precursor sensitivity, HCHO/NO , H O /HNO , O /NO , O /NO , O /HNO , and H O /NO , were evaluated based on the distribution of NO - and VOC-sensitive regimes. WRF-Chem was used to study a serious ozone episode in fall over the Pearl River Delta (PRD). It was found that the south-west of the PRD is characterized by a VOC-sensitive regime, while its north-east is NO -sensitive, with a sharp transition area between the two regimes. All indicators produced good representations of the elevated ozone hours in the episode on 6 November 2009, with H O /HNO being the best indicator. The threshold sensitivity levels for HCHO/NO , H O /HNO , O /NO , O /NO , O /HNO , and H O /NO were estimated to be 0.41, 0.55, 10.2, 14.0, 19.1, and 0.38, respectively. Threshold intervals for the indicators H O /HNO , O /NO , O /NO , O /HNO , and H O /NO were able to identify more than 95% of VOC- and NO -sensitive grids. The ozone episode on 16 November 16 2008 was used to independently verify the results, and it was found that only H O /HNO and H O /NO were able to differentiate the ozone sensitivity regime well. Hence, these two ratios are suggested as the most appropriate indicators for identifying fall ozone sensitivity in the PRD. Since the species used for indicators have seasonal variation, the utility of those indicators for other seasons should be investigated in the future work.

关键词： Ozone     Pearl River Delta (PRD)     Sensitivity regime     Photochemical indicator     Threshold levels    

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Space view of the decadal variation for typical air pollutants in the Pearl River Delta (PRD) region

Zifeng WANG, Min SHAO, Liangfu CHEN, Minghui TAO, Liuju ZHONG, Duohong CHEN, Meng FAN, Yang WANG, Xinhui WANG

《环境科学与工程前沿（英文）》 2016年 第10卷 第5期 doi: 10.1007/s11783-016-0853-y

摘要： Spatial and temporal trends of the typical pollutants in PRD viewed from space. Comparisons of the satellite retrievals with the collocated in situ data are given. Among different MCs, the control measures applied in PRD are the most effective. The unique HCHO trends imply significant contribution from the biogenic origins. The Pearl River Delta (PRD) is one of the most industrialized, urbanized and populated regions in China, and thus has been long suffering from severe air pollutions. Space data provide a unique perspective for investigating the atmospheric environment at a regional scale. By utilizing multiple satellite retrievals from 2005 to 2013, this study presented, for the first time, the spatial patterns and temporal trends of typical air pollutants over PRD and its vicinity. As viewed from space, aerosol optical depth (AOD), NO2 and SO2 all had their higher values at the central part of PRD, and showed clear descending gradients as moving to the outskirt of this region. As to the inter-annual variation, all these pollutants had decreasing trends in PRD during the study period, which generally agreed with the relevant in situ measurements. However, the satellite retrievals differed from ground measurements when addressing NO2 and SO2 in the vicinity of PRD. This work also provides the inter-comparison among PRD and three other metropolitan clusters in China: PRD had relatively high AOD, moderate NO2 and low SO2 levels, and it was the only region achieving the effective reduction of NO2 and SO2 during last decade. Unlike the previous three pollutants, HCHO observed by satellite showed very special patterns: it had a relatively homogeneous spatial distribution over both of PRD and its vicinity, and presented an opposite increasing trend from 2005 to 2010. Moreover, PRD had the highest HCHO level among all the metropolitan clusters, hinting a considerable contribution of biogenic origins of HCHO in PRD.

关键词： The Pearl River Delta (PRD)     Satellite monitoring     Regional air quality     Long-term trend     HCHO    

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Response of organic aerosol characteristics to emission reduction in Yangtze River Delta region

《环境科学与工程前沿（英文）》 2023年 第17卷 第9期 doi: 10.1007/s11783-023-1714-0

摘要：

● The emission reduction causes significant change in organic aerosol composition.

关键词： Emission control     Secondary organic aerosol     Atmospheric oxidizing capacity     Holiday effects     COVID-19 lockdown    

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Neutralization against SARS-CoV-2 Delta/Omicron variants and B cell response after inactivated vaccination

《医学前沿（英文）》 2023年 第17卷 第4期   页码 747-757 doi: 10.1007/s11684-022-0954-x

摘要： Emerging SARS-CoV-2 variants have made COVID-19 convalescents susceptible to re-infection and have raised concern about the efficacy of inactivated vaccination in neutralization against emerging variants and antigen-specific B cell response. To this end, a study on a long-term cohort of 208 participants who have recovered from COVID-19 was conducted, and the participants were followed up at 3.3 (Visit 1), 9.2 (Visit 2), and 18.5 (Visit 3) months after SARS-CoV-2 infection. They were classified into three groups (no-vaccination (n = 54), one-dose (n = 62), and two-dose (n = 92) groups) on the basis of the administration of inactivated vaccination. The neutralizing antibody (NAb) titers against the wild-type virus continued to decrease in the no-vaccination group, but they rose significantly in the one-dose and two-dose groups, with the highest NAb titers being observed in the two-dose group at Visit 3. The NAb titers against the Delta variant for the no-vaccination, one-dose, and two-dose groups decreased by 3.3, 1.9, and 2.3 folds relative to the wild-type virus, respectively, and those against the Omicron variant decreased by 7.0, 4.0, and 3.8 folds, respectively. Similarly, the responses of SARS-CoV-2 RBD-specific B cells and memory B cells were boosted by the second vaccine dose. Results showed that the convalescents benefited from the administration of the inactivated vaccine (one or two doses), which enhanced neutralization against highly mutated SARS-CoV-2 variants and memory B cell responses. Two doses of inactivated vaccine among COVID-19 convalescents are therefore recommended for the prevention of the COVID-19 pandemic, and vaccination guidelines and policies need to be updated.

关键词： COVID-19 convalescent     SARS-CoV-2     inactivated vaccination     neutralizing antibody     B cell response    

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PPCPs in a drinking water treatment plant in the Yangtze River Delta of China: Occurrence, removal and

Xinshu Jiang, Yingxi Qu, Liquan Liu, Yuan He, Wenchao Li, Jun Huang, Hongwei Yang, Gang Yu

《环境科学与工程前沿（英文）》 2019年 第13卷 第2期 doi: 10.1007/s11783-019-1109-4

摘要：

• 39 PPCPs were investigated at a DWTP using the Yangtze River as its water source.

• Grab and continuous sampling were conducted for the comparison of data consistency.

• Ketoprofen & carbamazepine can be risk management indicators because of the high RQ.

关键词： PPCPs     DWTP     Human health risk assessment    

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Lung function and air pollution exposure in adults with asthma in Beijing: a 2-year longitudinal panel

《医学前沿（英文）》 2022年 第16卷 第4期   页码 574-583 doi: 10.1007/s11684-021-0882-1

摘要： The effect of air pollution on the lung function of adults with asthma remains unclear to date. This study followed 112 patients with asthma at 3-month intervals for 2 years. The pollutant exposure of the participants was estimated using the inverse distance weight method. The participants were divided into three groups according to their lung function level at every visit. A linear mixed-effect model was applied to predict the change in lung function with each unit change in pollution concentration. Exposure to carbon monoxide (CO) and particles less than 2.5 micrometers in diameter (PM2.5) was negatively associated with large airway function in participants. In the severe group, exposure to chronic sulfur dioxide (SO2) was negatively associated with post-bronchodilator forced expiratory flow at 50%, between 25% and 75% of vital capacity % predicted (change of 95% CI per unit: −0.34 (−0.55, −0.12), −0.24 (−0.44, −0.03), respectively). In the mild group, the effect of SO2 on the small airways was similar to that in the severe group, and it was negatively associated with large airway function. Exposure to CO and PM2.5 was negatively associated with the large airway function of adults with asthma. The negative effects of SO2 were more evident and widely observed in adults with severe and mild asthma than in adults with moderate asthma. Patients with asthma react differently to air pollutants as evidenced by their lung function levels.

关键词： lung function     asthma     air pollution     adult    

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珠江三角洲地区生态文明建设提升战略研究

王金南 ,蒋洪强 ,吴文俊 ,刘年磊 ,段扬 ,王明旭

《中国工程科学》 2022年 第24卷 第6期   页码 154-163 doi: 10.15302/J-SSCAE-2022.06.014

摘要：

生态文明建设是国家发展战略，研究经济发达地区生态文明建设的经验模式与提升策略，对发挥带动和示范效应、推 进全国生态文明建设具有重要意义。本文以珠江三角洲（珠三角）地区的生态文明建设为案例，系统梳理了生态空间格局、 生态环境质量、生态文明制度、经济环境协调发展等方面取得的成效，总结提炼了生态文明建设的创新模式；在深入分析区 域生态文明建设面临挑战的基础上，针对性提出了发展目标与发展路径，以期为我国经济发达地区的生态文明建设提供基本 参照。研究建议，提升国土空间保护修复水平，推动珠三角地区率先实现碳排放达峰，以科技创新引领绿色低碳高质量发 展，促进天蓝地绿水清，使环境得到持续改善，营造美丽宜居与生态文明新风尚，以此构建生态文明制度创新高地。

关键词： 生态文明；珠江三角洲；建设模式；生态环境；碳排放达峰；制度创新    

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Characterization of submicron aerosols in the urban outflow of the central Pearl River Delta region of

Zhaoheng GONG, Zijuan LAN, Lian XUE, Liwu ZENG, Lingyan HE, Xiaofeng HUANG

《环境科学与工程前沿（英文）》 2012年 第6卷 第5期   页码 725-733 doi: 10.1007/s11783-012-0441-8

摘要： Submicron aerosol particles (with aerodynamic diameters less than 1 μm, PM ) were sampled and measured in Heshan, an urban outflow site of Guangzhou megacity in Pearl River Delta in South China, using an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) in November 2010 during 2010 Guangzhou Asian Games. The mean PM mass concentration measured was 47.9±17.0 μg·m during the campaign, with organic aerosol (OA) and sulfate being the two dominant species, accounting for 36.3% and 20.9% of the total mass, respectively, followed by black carbon (17.1%, measured by an aethalometer), nitrate (12.9%), ammonium (9.6%) and chloride (3.1%). The average size distributions of the species (except black carbon) were dominated by an accumulation mode peaking at ~550 nm. Calculations based on high-resolution organic mass spectrum showed that, C, H, O and N on average contributed 58.1%, 7.3%, 30.7%, and 3.9% to the total organic mass, respectively. The average ratio of organic mass over organic carbon mass (OM/OC) was 1.73±0.08. Four components of OA were identified by the Positive Matrix Factorization (PMF) analysis, including a hydrocarbon-like (HOA), a biomass burning (BBOA) and two oxygenated (SV-OOA and LV-OOA) organic aerosol components, which on average accounted for 18.0%, 14.3%, 28.8% and 38.9% of the total organic mass, respectively.

关键词： organic aerosol     high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS)     positive matrix factorization    

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The function and regulation of OTU deubiquitinases

Jiansen Du, Lin Fu, Yingli Sui, Lingqiang Zhang

《医学前沿（英文）》 2020年 第14卷 第5期   页码 542-563 doi: 10.1007/s11684-019-0734-4

摘要： Post-translational modification of cellular proteins by ubiquitin regulates numerous cellular processes, including cell division, immune responses, and apoptosis. Ubiquitin-mediated control over these processes can be reversed by deubiquitinases (DUBs), which remove ubiquitin from target proteins and depolymerize polyubiquitin chains. Recently, much progress has been made in the DUBs. In humans, the ovarian tumor protease (OTU) subfamily of DUBs includes 16 members, most of which mediate cell signaling cascades. These OTUs show great variation in structure and function, which display a series of mechanistic features. In this review, we provide a comprehensive analysis of current progress in character, structure and function of OTUs, such as the substrate specificity and catalytic activity regulation. Then we discuss the relationship between some diseases and OTUs. Finally, we summarize the structure of viral OTUs and their function in immune escape and viral survival. Despite the challenges, OTUs might provide new therapeutic targets, due to their involvement in key regulatory processes.

关键词： ubiquitin     OTU deubiquitinases     structure     function     regulation    

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标题 作者 时间 类型 操作

Discontinuous mechanical behaviors of existing shield tunnel with stiffness reduction at longitudinal joints

期刊论文

原子质量的相对论效应和应用

朱正和,傅依备,蒙大桥,唐永健

期刊论文

An improved delta-star switching scheme for reactive power saving in three-phase induction motors

P. RAJA,N. KUMARESAN,M. SUBBIAH

期刊论文

Energy internet in the Yangtze River Delta: opportunities, challenges, and suggestions

Zheng YAN, Jiayi HU

期刊论文

Long-term trends of fine particulate matter and chemical composition in the Pearl River Delta Economic

Xuemei WANG,Weihua CHEN,Duohong CHEN,Zhiyong WU,Qi Fan

期刊论文

attribution for mercury deposition with an updated atmospheric mercury emission inventory in the Pearl River Delta

Jiajun Liu, Long Wang, Yun Zhu, Che-Jen Lin, Carey Jang, Shuxiao Wang, Jia Xing, Bin Yu, Hui Xu, Yuzhou Pan

期刊论文

Photochemical indicators of ozone sensitivity: application in the Pearl River Delta, China

Lyumeng Ye,Xuemei Wang,Shaofeng Fan,Weihua Chen,Ming Chang,Shengzhen Zhou,Zhiyong Wu,Qi Fan

期刊论文

Space view of the decadal variation for typical air pollutants in the Pearl River Delta (PRD) region

Zifeng WANG, Min SHAO, Liangfu CHEN, Minghui TAO, Liuju ZHONG, Duohong CHEN, Meng FAN, Yang WANG, Xinhui WANG

期刊论文

Response of organic aerosol characteristics to emission reduction in Yangtze River Delta region

期刊论文

Neutralization against SARS-CoV-2 Delta/Omicron variants and B cell response after inactivated vaccination

期刊论文

PPCPs in a drinking water treatment plant in the Yangtze River Delta of China: Occurrence, removal and

Xinshu Jiang, Yingxi Qu, Liquan Liu, Yuan He, Wenchao Li, Jun Huang, Hongwei Yang, Gang Yu

期刊论文

Lung function and air pollution exposure in adults with asthma in Beijing: a 2-year longitudinal panel

期刊论文

珠江三角洲地区生态文明建设提升战略研究

王金南 ,蒋洪强 ,吴文俊 ,刘年磊 ,段扬 ,王明旭

期刊论文

Characterization of submicron aerosols in the urban outflow of the central Pearl River Delta region of

Zhaoheng GONG, Zijuan LAN, Lian XUE, Liwu ZENG, Lingyan HE, Xiaofeng HUANG

期刊论文

The function and regulation of OTU deubiquitinases

Jiansen Du, Lin Fu, Yingli Sui, Lingqiang Zhang

期刊论文