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Ultra-precision machining of cerium-lanthanum alloy with atmosphere control in an auxiliary device

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Nanotechnology and Precision Engineering 2022年第3期5卷 30-35页

作者： Chenyu Zhao shengjie Wu Min lai State Key Laboratory of Precision Measuring Technology and Instruments Laboratory of Micro/Nano Manufacturing TechnologyTianjin UniversityTianjin 300072China

Cerium–lanthanum alloys are the main component of nickel–metal hydride batteries,and they are thus an important material in the greenenergy industry.However,these alloys have very strong chemical activity,and their surfaces are easily oxidized,leading to great difficulties in their application.To improve the corrosion resistance of cerium–lanthanum alloys,it is necessary to obtain a nanoscale surface with low roughness.However,these alloys can easily succumb to spontaneous combustion during machining.Currently,to inhibit the occurrence of fire,machining of this alloy in ambient air needs to be conducted at very low cutting speeds while spraying the workpiece with a large amount of cutting fluid.However,this is inefficient,and only a very limited range of parameters can be optimized at low cutting speeds;this restricts the optimization of other cutting parameters.To achieve ultraprecision machining of cerium–lanthanum alloys,in this work,an auxiliary machining device was developed,and its effectiveness was verified.The results show that the developed device can improve the cutting speed and obtain a machined surface with low roughness.The device can also improve the machining efficiency and completely prevent the occurrence of spontaneous combustion.It was found that the formation of a build-up of swarf on the cutting tool is eliminated with high-speed cutting,and the surface roughness(Sa)can reach 5.64 nm within the selected parameters.Finally,the oxidation processes of the cerium–lanthanum alloy and its swarf were studied,and the process of the generation of oxidative products in the swarf was elucidated.The results revealed that most of the intermediate oxidative products in the swarf were Ce^(3+),there were major oxygen vacancies in the swarf,and the final oxidative product was Ce^(4+).

关键词： Cerium–lanthanum alloy Ultraprecision machining Surface roughness Atmosphere control

Near-Infrared All-Fused-Ring Nonfullerene Acceptors Achieving an Optimal Efficiency-Cost-Stability Balance in Organic Solar Cells

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CCS Chemistry 2023年第3期5卷 654-668页

作者： Wenrui Liu shengjie Xu Hanjian lai Wuyue Liu Feng He Xiaozhang Zhu Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Organic Solids Institute of ChemistryChinese Academy of SciencesBeijing 100190 School of Chemical Sciences University of Chinese Academy of SciencesBeijing 100049 Department of Chemistry Shenzhen Grubbs InstituteSouthern University of Science and TechnologyShenzhen 518055

Synergistically achieving stability,cost,and efficiency is crucial for the commercialization of organic solar cells(OSCs).Despite the rapid development of 2-(3-oxo-2,3-dihydro-1H-inden-1-ylidene)malo nonitriletypenon fullerene acceptors(NFAs),they areinherently unstable due to the vulnerable exocyclic double bond and possess high synthesis complexity(SC).Based on the“all-fused-ring electron acceptor(AFAR)”concept,we report two new near-infrared NFAs,F11 and F13,featuring all fused dodecacyclic rings.By developing a whole set of synthetic procedures,F11 and F13 can be conveniently prepared at a 10 g scale within a notably short period,displaying both the low SC and the lowest costs among reported NFAs,even comparable to the classical photovoltaic material,P3HT.In comparison with the one-dimensional stacking of ITYM(ITYM=2,2′-(7,7,15,15-tetrahexyl-7,15-dihydro-s-indaceno[1,2-b:5,6-b′]diindeno[1,2-d]thiophene-2,10(2H)-diylidene)dimalononitrile),the first AFRA,and mixed J-and H-aggregations in Y6,F-acceptors show a compact honeycomb-type three-dimensional stacking with exclusive J-aggregations,favoring multichannel charge transport.By matching a medium-bandgap polymer donor,F13 delivers greater than 13%power conversion efficiencies,which is the highest performance among non-INCN acceptors,and shows device stability superior to the typical ITIC-and Y6-based OSCs as evidenced by the negligible burn-in losses.This work presents a first and successful example of NFAs achieving an optimal efficiency-cost-stability balance in OSCs.

关键词： nonfullerene acceptors near-infrared cost stability power conversion efficiency

The Incoming Influenza Season—China,the United Kingdom,and the United States,2021–2022

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China CDC weekly 2021年第49期3卷 1039-1045页

作者： Shasha Han Ting Zhang Yan Lyu Shengjie Lai Peixi Dai Jiandong Zheng Weizhong Yang Xiaohua Zhou Luzhao Feng Beijing International Center for Mathematical Research Peking UniversityBeijingChina Harvard Medical School Harvard UniversityBostonMAUSA School of Population Medicine and Public Health Chinese Academy of Medical Sciences&Peking Union Medical CollegeBeijingChina Academy for Advanced Interdisciplinary Studies Peking UniversityBeijingChina WorldPop School of Geography and Environmental ScienceUniversity of SouthamptonSouthamptonUK Division for Infectious Diseases Chinese Center for Disease Control and PreventionBeijingChina Department of Biostatistics School of Public HealthPeking UniversityBeijingChina National Engineering Laboratory of Big Data Analysis and Applied Technology Peking UniversityBeijingChina.

Introduction:Seasonal influenza activity has declined globally since the widespread of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)transmission.There has been scarce information to understand the future dynamics of influenza—and under different hypothesis on relaxation of nonpharmaceutical interventions(NPIs)in particular—after the disruptions to seasonal patterns.Methods:We collected data from public sources in China,the United Kingdom,and the United States,and forecasted the influenza dynamics in the incoming 2021–2022 season under different NPIs.We considered Northern China and Southern China separately,due to the sharp difference in the patterns of seasonal influenza.For the United Kingdom,data were collected for England only.Results:Compared to the epidemics in 2017–2019,longer and blunter influenza outbreaks could occur should NPIs be fully lifted,with percent positivity varying from 10.5 to 18.6 in the studying regions.The rebounds would be smaller if the maskwearing intervention continued or the international mobility stayed low,but sharper if the mask-wearing intervention was lifted in the middle of influenza season.Further,influenza activity could stay low under a much less stringent mask-wearing intervention coordinated with influenza vaccination.Conclusions:The results added to our understandings of future influenza dynamics after the global decline during the coronavirus disease 2019(COVID-19)pandemic.In light of the uncertainty on the incoming circulation strains and the relatively low negative impacts of mask wearing on society,our findings suggested that wearing mask could be considered as an accompanying mitigation measure in influenza prevention and control,especially for seasons after long periods of low-exposure to influenza viruses.Seasonal influenza activity declines globally during the coronavirus disease 2019(COVID-19)pandemic(1–4).For instance,in China,influenza activity,as measured by percentage of submitted specimens testing positive,dropped from 11.8%to 2.0%in 2020–2021

关键词： prevention globally continued

应急状态下新冠流行曲线预测的方法学研究——基于北京市百度搜索和传统流感样病例监测

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Engineering 2023年第12期31卷 112-119页

作者： Ting Zhang Liuyang Yang Xuan Han Guohui Fan Jie Qian Xuancheng Hu Shengjie Lai Zhongjie Li Zhimin Liu Luzhao Feng Weizhong Yang School of Population Medicine and Public Health Chinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100730China Department of management science and information system Faculty of Management and EconomicsKunming University of Science and TechnologyKunming 650504China WorldPop School of Geography and Environmental ScienceUniversity of SouthamptonSouthampton SO171BJUK The Third Affiliated Hospital of Kunming Medical University Kunming 650118China

Surveillance is an essential work on infectious diseases prevention and control.When the pandemic occurred,the inadequacy of traditional surveillance was exposed,but it also provided a valuable opportunity to explore new surveillance methods.This study aimed to estimate the transmission dynamics and epidemic curve of severe acute respiratory syndrome coronavirus 2(SARS-Co V-2)Omicron BF.7 in Beijing under the emergent situation using Baidu index and influenza-like illness(ILI)surveillance.A novel hybrid model(multiattention bidirectional gated recurrent unit(MABG)-susceptible-exposed-infected-removed(SEIR))was developed,which leveraged a deep learning algorithm(MABG)to scrutinize the past records of ILI occurrences and the Baidu index of diverse symptoms such as fever,pyrexia,cough,sore throat,anti-fever medicine,and runny nose.By considering the current Baidu index and the correlation between ILI cases and coronavirus disease 2019(COVID-19)cases,a transmission dynamics model(SEIR)was formulated to estimate the transmission dynamics and epidemic curve of SARS-Co V-2.During the COVID-19 pandemic,when conventional surveillance measures have been suspended temporarily,cases of ILI can serve as a useful indicator for estimating the epidemiological trends of COVID-19.In the specific case of Beijing,it has been ascertained that cumulative infection attack rate surpass 80.25%(95%confidence interval(95%CI):77.51%-82.99%)since December 17,2022,with the apex of the outbreak projected to transpire on December 12.The culmination of existing patients is expected to occur three days subsequent to this peak.Effective reproduction number(Rt)represents the average number of secondary infections generated from a single infected individual at a specific point in time during an epidemic,remained below 1 since December 17,2022.The traditional disease surveillance systems should be complemented with information from modern surveillance data such as online data sources with advanced technical support.Modern surveillance channels should

关键词： COVID-19 Epidemic curve Baidu search engine Influenza-like illness Deep learning Transmission dynamics model

Assessing the Effect of Global Travel and Contact Restrictions on Mitigating the COVID-19 Pandemic

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Engineering 2021年第7期7卷 914-923页

作者： Shengjie Lai Nick W.Ruktanonchai Alessandra Carioli Corrine W.Ruktanonchai Jessica R.Floyd Olivia Prosper Chi Zhang Xiangjun Du Weizhong Yang Andrew J.Tatem WorldPop School of Geography and Environmental ScienceUniversity of SouthamptonSouthampton SO171BJUK Population Health Sciences Virginia TechBlacksburgVA 24061USA Department of Mathematics University of TennesseeKnoxvilleTN 37996USA School of Public Health(Shenzhen) Sun Yat-sen UniversityShenzhen 510275China School of Population Medicine and Public Health Chinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100730China

Travel restrictions and physical distancing have been implemented across the world to mitigate the coronavirus disease 2019(COVID-19)pandemic,but studies are needed to understand their effectiveness across regions and time.Based on the population mobility metrics derived from mobile phone geolocation data across 135 countries or territories during the first wave of the pandemic in 2020,we built a metapopulation epidemiological model to measure the effect of travel and contact restrictions on containing COVID-19 outbreaks across regions.We found that if these interventions had not been deployed,the cumulative number of cases could have shown a 97-fold(interquartile range 79–116)increase,as of May 31,2020.However,their effectiveness depended upon the timing,duration,and intensity of the interventions,with variations in case severity seen across populations,regions,and seasons.Additionally,before effective vaccines are widely available and herd immunity is achieved,our results emphasize that a certain degree of physical distancing at the relaxation of the intervention stage will likely be needed to avoid rapid resurgences and subsequent lockdowns.

关键词： COVID-19 Pandemic Population mobility Travel restriction Physical distancing

基于线芯-护层过渡电阻无功特性的交叉互联电缆故障测距

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电工技术学报 2024年第5期39卷 1372-1389页

作者：杨明嘉夏成军赖胜杰池梓斌华南理工大学电力学院广州510640 广东省新能源电力系统智能运行与控制企业重点实验室广州510663

高压电缆常见的接地方式是交叉互联接地,而交叉互联接地电缆故障时的测距相比单端接地或两端直接接地的电缆情况更为复杂,为此提出了基于线芯-护层过渡电阻无功特性的交叉互联电缆故障测距方法。首先,采集护层故障前后环流,构建不同电... 详细信息

高压电缆常见的接地方式是交叉互联接地,而交叉互联接地电缆故障时的测距相比单端接地或两端直接接地的电缆情况更为复杂,为此提出了基于线芯-护层过渡电阻无功特性的交叉互联电缆故障测距方法。首先,采集护层故障前后环流,构建不同电缆区段特征电流,判断故障发生区段;其次,考虑电缆金属护层对线芯的耦合作用和线路电容影响,建立交叉互联电缆的故障稳态等效阻抗模型,利用电缆首末两端线芯和护层的电压、电流推算电缆故障发生时不同区段沿线电压、电流,并基于同一位置电压相量对电缆参数进行修正;然后,利用故障点过渡电阻消耗无功功率为零的功率特性建立以故障距离为未知数的测距方程,采用二分法或弦截法等方法迭代计算求解得到故障点;最后,基于PSCAD/EMTDC仿真软件搭建了电缆故障模型,分析了故障距离、故障类型、过渡电阻、故障初相角等因素对故障测距方法的影响。结果表明,该方法的测距误差为0.4%左右,具有较高的准确性和有效性,对交叉互联接地电缆进行故障测距有一定的参考意义。

关键词：高压电缆交叉互联无功特性故障稳态故障测距

A Putative Chloroplast-Localized Ca2＋/H＋ Antiporter CCHA1 Is Involved in Calcium and pH Homeostasis and Required for PSII Function in Arabidopsis

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Molecular Plant 2016年第8期9卷 1183-1196页

作者： Chao Wang Weitao Xu Honglei Jin Taijie Zhang Jianbin lai Xuan Zhou Shengchun Zhang shengjie Liu Xuewu Duan Hongbin Wang Changlian Peng Chengwei Yang Guangdong Key Lab of Biotechnology for Plant Development College of Life Science South China Normal University Guangzhou 510631 China State Key Laboratory of Biocontrel and Guangdeng Key Laboratory of Plant Resources School of Life Sciences Sun Yat-sen University Guangzhou 510275 China Key Laboratory of Plant Resource Conservation and Sustainable Utilization South Ohina Botanical Garden Chinese Academy of Sciences Guangzheu Guangdong Province 510650 China

Calcium is important for chloroplast, not only in its photosynthetic but also nonphotosynthetic functions. Mul- tiple Ca2＋/H＋ transporters and channels have been described and studied in the plasma membrane and organ- elle membranes of plant cells; however, the molecular identity and physiological roles of chloroplast Ca2＋/H＋ antiporters have remained unknown. Here we report the identification and characterization of a member of the UPFO016 family, CCHA1 （a chloroplast-localized potential Ca2＋/H＋ antiporter）, in Arabidopsis thaliana. We observed that the ccha I mutant plants developed pale green leaves and showed severely stunted growth along with impaired photosystem II （PSII） function. CCHA1 localizes to the chloroplasts, and the levels of the PSII core subunits and the oxygen-evolving complex were significantly decreased in the ccha I mutants compared with the wild type. In high Ca2＋ concentrations, Arabidopsis CCHA1 partially rescued the growth defect of yeast gdtl3 null mutant, which is defective in a Ca2＋/H＋ antiporter. The cchal mutant plants also showed significant sensitivity to high concentrations of CaCI2 and MnCI2, as well as variation in pH. Taken these results together, we propose that CCHA 1 might encode a putative chloroplast-localized Ca2＋/H＋ antiporter with critical functions in the regulation of PSII and in chloroplast Ca2＋ and pH homeostasis in Arabidopsis.

关键词： Ca2＋/H＋ antiporter Ca2＋ homeostasis pH homeostasis CCHA1

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基于免疫遗传算法的装配顺序优化

同济大学学报（自然科学版） 2015年第6期43卷 944-950页

作者：苏强吴海龙赖盛杰同济大学经济与管理学院上海201804 上海交通大学机械与动力工程学院上海200240

采用装配角度、装配方向、装配稳定性和重定位次数4个指标构建装配顺序优化模型,并用疫苗自动获取的免疫遗传算法(IGABVAU)求解.提出4种免疫疫苗用于提升算法运行效率,其中KP和NL型疫苗由人工指定,BP和NT型疫苗在算法运行中自动获取.船... 详细信息

采用装配角度、装配方向、装配稳定性和重定位次数4个指标构建装配顺序优化模型,并用疫苗自动获取的免疫遗传算法(IGABVAU)求解.提出4种免疫疫苗用于提升算法运行效率,其中KP和NL型疫苗由人工指定,BP和NT型疫苗在算法运行中自动获取.船舶工段装配实验结果表明,该算法具有较快的收敛速度.进一步研究发现,免疫疫苗的质量会影响疫苗自动获取的免疫遗传算法收敛速度,人工指定的KP和NL型疫苗可以提高初始种群的质量,自动获取的BP和NT型疫苗可以为装配顺序的进化提供方向.

关键词：免疫遗传算法疫苗自动更新装配顺序规划

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传染病智慧化症状监测的进展与挑战

中华流行病学杂志 2023年第9期44卷 1338-1343页

作者：范国辉张婷赖圣杰冯录召杨维中中国医学科学院北京协和医学院群医学及公共卫生学院北京100730 呼吸和共病全国重点实验室北京100730 病原体感染防控教育部重点实验室(北京协和医学院) 北京100730 英国南安普顿大学地理与环境科学学院南安普顿SO171BJ

智慧化症状监测是我国传染病智慧化预警多点触发和多渠道预警体系的重要组成部分,是传统症状监测在新技术发展下的必然路径。智慧化症状监测不仅包括医院就诊患者的大量医疗数据,还囊括未在医院就诊、海量的非医疗数据。然而,发展的同... 详细信息

智慧化症状监测是我国传染病智慧化预警多点触发和多渠道预警体系的重要组成部分,是传统症状监测在新技术发展下的必然路径。智慧化症状监测不仅包括医院就诊患者的大量医疗数据,还囊括未在医院就诊、海量的非医疗数据。然而,发展的同时也迎来了挑战,如信息爆炸、成本-效益问题以及数据共享、数据安全和隐私问题。本文通过对智慧化症状监测相关概念发展的思考和总结,为传染病智慧化预警方法与技术的发展提供参考,为我国和全球传染病防控提供新思路。

关键词：智慧化症状监测传染病防控进展挑战