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Evaluation and attribution of trends in compound dry-hot events for major river basins in China

Science China Earth Sciences 2024年第1期67卷 79-91页

作者： Shaotang XIONG Tongtiegang ZHAO chengchao GUO Yu TIAN Fang YANG wenlong chen Xiaohong chen Key Laboratory of Water Security Guarantee in Guangdong-Hong Kong-Marco Greater Bay Area of Ministry of Water Resources&Sun Yatsen University/Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Guangzhou 510275China China Institute of Water Resource and Hydropower Research Beijing 100038China Pearl River Hydraulic Research Institute Guangzhou 510611China

Concurrent compound dry and hot events(CDHEs)amplified more damange on the ecosystems and human society than individual extremes.Under climate change,compound dry and hot events become more frequent on a global scale.This paper proposes a mathematical method to quantitatively attribute changes of CDHEs to changes of precipitation,change in temperature and change in the dependence between precipitation and temperature.The attribution is achieved by formulating the total differential equation of the return period of CDHEs among Meta-gaussian model.A case study of China is devised based on monthly precipitation and temperature data during the period from 1921 to 2020 for 80 major river basins.It is found that temperature is the main driving factor of increases in CDHEs for 49 major river basins in China,except for the upper and middle reaches of the Yangtze River.In West China,precipitation changes drove the increase in CDHEs in 18 river basins(23%),particularly in parts of North Xinjiang,Qinghai and Gansu.On the other hand,dependence between precipitation and temperature dominated changes of CDHEs in 13 river basins(16%)of China with other factors,including parts of South China,East China and Northwestern China.Furthermore,changes in both the mean and spread of precipitation and temperature can also contribute to changes in CDHEs.

关键词： Climate extreme Compound dry and hot extreme Precipitation Temperature Return period

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Influence of heat treatment on microstructure,mechanical and corrosion behavior of WE43 alloy fabricated by laser-beam powder bed fusion

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International Journal of Extreme Manufacturing 2024年第1期6卷 258-275页

作者： chenrong Ling Qiang Li Zhe Zhang Youwen Yang Wenhao Zhou wenlong chen Zhi Dong Chunrong Pan Cijun Shuai College of Mechanical and Electrical Engineering Jiangxi University of Science and TechnologyGanzhou 341000People’s Republic of China School of Mechanical and Electronic Engineering Suzhou UniversitySuzhou 234000People’s Republic of China Shaanxi Key Laboratory of Biomedical Metal Materials Northwest Institute for Non-ferrous Metal ResearchXi’an 710016People’s Republic of China Department of Orthopedics First Afffliated Hospital of Gannan Medical CollegeGanzhou 341000People’s Republic of China School of Mechanical and Automotive Engineering South China university of technologyGuangzhou 510641People’s Republic of China State Key Laboratory of High-Performance Complex Manufacturing Central South UniversityChangsha 410083People’s Republic of China Double Medical Technology Inc. Xiamen 361026People’s Republic of China

Magnesium(Mg)alloys are considered to be a new generation of revolutionary medical metals.Laser-beam powder bed fusion(PBF-LB)is suitable for fabricating metal implants withpersonalized and complicated structures.However,the as-built part usually exhibits undesirable microstructure and unsatisfactory performance.In this work,WE43 parts were firstly fabricated by PBF-LB and then subjected to heat treatment.Although a high densification rate of 99.91%was achieved using suitable processes,the as-built parts exhibited anisotropic and layeredmicrostructure with heterogeneously precipitated Nd-rich intermetallic.After heat treatment,fine and nano-scaled Mg24Y5particles were precipitated.Meanwhile,theα-Mg grainsunderwent recrystallization and turned coarsened slightly,which effectively weakened thetexture intensity and reduced the anisotropy.As a consequence,the yield strength and ultimate tensile strength were significantly improved to(250.2±3.5)MPa and(312±3.7)MPa,respectively,while the elongation was still maintained at a high level of 15.2%.Furthermore,the homogenized microstructure reduced the tendency of localized corrosion and favoredthe development of uniform passivation film.Thus,the degradation rate of WE43 parts was decreased by an order of magnitude.Besides,in-vitro cell experiments proved their favorable biocompatibility.

关键词： laser-beam powder bed fusion WE43 alloys heat treatment mechanical performance biodegradation behavior

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LPR-Trie: A Fast IPv6 Routing Lookup Algorithm with Virtual Nodes

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China Communications 2022年第10期19卷 1-11页

作者： wenlong chen Diya Liu Jiacheng Wang Xiaolan Tang The College of Information Engineering Capital Normal UniversityBeijing 100048China

The number of IPv6 routes in todays backbone routers has grown rapidly,which has put tremendous pressure on route lookup and storage.Based on the analysis of IPv6 address prefix length and distribution characteristics,this paper proposes an IPv6 route lookup architecture called LPR-Trie.The core idea of the algorithm is to utilize more spaces and accelerate routing lookup.Moreover,we put forward the concept of virtual nodes,and leverage the link between virtual nodes and ordinary nodes to accelerate routing lookup.We provide the longest prefix routing entry(LPR)calculation algorithm to achieve the longest prefix match.The experimental results show that the virtual node mechanism increases the search speed up to 244%,and the virtual nodes have better stability by setting an appropriate keep-alive time according to the characteristics of actual traffic.This paper shows that our design improves the routing lookup speed and have better memory utilization.

关键词： IPv6 route lookup longest prefix match virtual node Trie

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基于低水位运行的城市河流污染底泥中微生物群落特征及影响因素

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水资源保护 2024年第2期40卷 126-133页

作者：吴琼陈文龙陈军珠江水利委员会珠江水利科学研究院广东广州510611 水利部珠江河口治理与保护重点实验室广东广州510611 广东省河湖生命健康工程技术研究中心广东广州510611

针对低水位运行修复城市河流污染底泥微生物机制不清的问题,基于高、低水位下不同城市河流的底泥理化性质检测分析、宏基因组高通量测序及生物信息学分析等手段,开展了低水位运行的城市河流污染底泥中微生物群落特征及影响因素研究。结... 详细信息

针对低水位运行修复城市河流污染底泥微生物机制不清的问题,基于高、低水位下不同城市河流的底泥理化性质检测分析、宏基因组高通量测序及生物信息学分析等手段,开展了低水位运行的城市河流污染底泥中微生物群落特征及影响因素研究。结果表明:变形菌门、放线菌门、厚壁菌门和广古菌门分别是不同水位运行条件下相对丰度最高的细菌门类和古菌门类;高水位运行条件下底泥中细菌的香农指数显著高于低水位运行条件下的指数值(p<0.001),古菌则相反,说明古菌群落可能主导了低水位运行过程中底泥污染物降解过程;低水位运行时变形菌门可能是参与底泥中含氮污染物降解以及氮循环过程的主要微生物门类,α-变形菌纲则可能对底泥中氨氮的去除发挥了重要作用;TOC,TN和NH_(3)-N是影响城市河流底泥中微生物群落变化的主要环境驱动因子;低水位运行不仅能够有效降低底泥中常规污染指标的污染程度,解决底泥内源污染问题,还能显著降低底泥中致病菌的潜在危害,构建更为安全的亲水城市河流生态系统。

关键词：城市河流污染底泥低水位运行微生物修复机制

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Experimental and numerical studies on progressive debonding of grouted rock bolts

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International Journal of Mining Science and Technology 2022年第1期32卷 63-74页

作者： Hao Shi Lei Song Houquan Zhang wenlong chen Huasheng Lin Danqi Li Guozhu Wang Huayun Zhao State Key Laboratory for Geomechanics&Deep Underground Engineering School of Mechanics&Civil EngineeringChina University of Mining and TechnologyXuzhou 221116China School of Civil Engineering and Architecture Anhui University of Science and TechnologyHuainan 232001China School of Water Energy and EnvironmentCranfield UniversityCranfield MK430ALUK Glencore Coal Assets Australia Mount ThorleyNSW 2330Australia WA School of Mines:Minerals Energy and Chemical EngineeringCurtin UniversityKalgoorlie WA6430Australia

Understanding the mechanism of progressive debonding of bolts is of great significance for underground safety.In this paper,both laboratory experiment and numerical simulation of the pull-out tests were performed.The experimental pull-out test specimens were prepared using cement mortar material,and a relationship between the pull-out strength of the bolt and the uniaxial compressive strength(UCS)of cement mortar material specimen was established.The locations of crack developed in the pull-out process were identified using the acoustic emission(AE)technique.The pull-out test was reproduced using 2D Particle Flow Code(PFC^(2D))with calibrated parameters.The experimental results show that the axial displacement of the cement mortar material at the peak load during the test was approximately 5 mm for cement-based grout of all strength.In contrast,the peak load of the bolt increased with the UCS of the confining medium.Under peak load,cracks propagated to less than one half of the anchorage length,indicating a lag between crack propagation and axial bolt load transmission.The simulation results show that the dilatation between the bolt and the rock induced cracks and extended the force field along the anchorage direction;and,it was identified as the major contributing factor for the pull-out failure of rock bolt.

关键词： Bolt pull-out test Bolt failure process AE positioning Meso-interaction PFC2D simulation

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Thermally activated delayed fluorescence molecules and their new applications aside from OLEDs

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Chinese Chemical Letters 2019年第10期30卷 1717-1730页

作者： wenlong chen Fengling Song State Key Laboratory of Fine Chemicals School of Chemical EngineeringDalian University of TechnologyDalian 116024China Institute of Molecular Sciences and Engineering Shandong UniversityQingdao 266237China

Thermally activated delayed fluorescence(TADF) organic molecules feature with long-lived delayed fluorescence, because they can undergo not only efficient intersystem crossing(ISC), but also efficient reverse intersystem crossing(RISC) at room temperature. As a new type of luminescent molecules, they have exhibited successful applications in organic light emitting diodes(OLEDs). Aside from OLEDs, they are also found to have potential applications in time-resolved luminescence imaging based on long-lived fluorescence property. Meanwhile, due to their excited triplet characteristic originated from efficient ISC,they were found to be applied in triplet-triplet annihilation upconversion(TTA-UC), photodynamic therapy(PDT) and organic photocatalytic synthesis. This review briefly summarizes the characteristics and excellent photophysical properties of TADF organic compounds, then covers their applications to date aside from OLEDs based on their highly efficient ISC ability and RISC ability at room temperature.

关键词： Thermally activated delayed fluorescence Intersystem crossing Time-resolved luminescence Triplet-triplet annihilation upconversion Photodynamic therapy Organic photocatalytic synthesis

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城市河流低水位运行生态修复机制与实践效果

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水资源保护 2024年第2期40卷 16-22页

作者：陈文龙吴琼李一平珠江水利委员会珠江水利科学研究院广东广州510611 水利部珠江河口治理与保护重点实验室广东广州510611 广东省河湖生命健康工程技术研究中心广东广州510611 河海大学环境学院江苏南京210098

为厘清城市河流低水位运行的水生态修复机制,开展了垂向监测水和底泥理化指标、定量监测微生物功能基因、测定微生物活性等室内模拟试验,分析了泥-水界面环境因子及底泥溶解氧的变化特征,研究了底泥主要污染物和功能微生物的变化特征,... 详细信息

为厘清城市河流低水位运行的水生态修复机制,开展了垂向监测水和底泥理化指标、定量监测微生物功能基因、测定微生物活性等室内模拟试验,分析了泥-水界面环境因子及底泥溶解氧的变化特征,研究了底泥主要污染物和功能微生物的变化特征,揭示了低水位运行下污染底泥上层硝化和下层反硝化的协同耦合过程。结果表明:低水位运行可改变底泥的“源-汇”属性,高水位时的“源”转变成低水位的“汇”,继而实现水质的提升;伴随着污染底泥的修复,可逐步形成“底栖动物-沉水植物-挺水植物-昆虫-鸟类”的多营养级完整水生态系统;污染底泥治理是生态修复的关键,城市河流在低水位运行模式下可实现底泥自修复和生态系统构建。

关键词：城市河流低水位运行底泥污染生态修复

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High-temperature oxidation behavior and analysis of impedance spectroscopy of 7YSZ thermal barrier coating prepared by plasma spray-physical vapor deposition

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Chinese Journal of Aeronautics 2018年第8期31卷 1764-1773页

作者： wenlong chen Min LIU Jifu ZHANG Ziqian DENG Jie MAO School of Materials and Energy Guangdong University of Technology Guangzhou 510006 China National Engineering Laboratory for Modern Materials Surface Engineering Technology & the Key Lab of Guangdong for Modern Surface Engineering Technology Guangdong Institute of New Materials Guangzhou 510650 China

Quasi-columnar structure 7YSZ（yttria stabilized zirconia） thermal barrier coatings（TBCs） are prepared by plasma spray-physical vapor deposition（PS-PVD） onto pretreated and un-pretreated bond coating, respectively. An isothermal oxidation experiment of 7YSZ TBCs is carried out in the atmosphere of 950 °C in order to simulate the high-temperature oxidation process of engine blades. The isothermal oxidation process of 7YSZ thermal barrier coatings is investigated systematically by impedance spectroscopy. The electrochemical physical model and equivalent circuit of columnar 7YSZ coatings are established. Results show that the isothermal oxidation kinetic curve of columnar 7YSZ thermal barrier coatings appears to follow the parabolic law. A pretreatment of bond coating can reduce the growth rate of the thermally grown oxide（TGO） layer, restraining the initiation and propagation of microcracks between YSZ and TGO layers. The oxidation rate constants of 7YSZ coatings with pretreated and un-pretreated bond coating are 0.101×10^（-12） cm^2·s^（-1） and 0.115 × 10^（-13） cm^2 ·s^（-1）, respectively. Impedance analysis shows that the content of oxygen vacancies decreases and the density increases after the TGO layer is oxidized for 150 h. In addition, shrinkage microcracks formed by sintering during the oxidation process is the main reason for an increase of the capacitance and a decrease of the resistance in the grain boundary of YSZ.

关键词： Bond coating Impedance spectroscopyIsothermal oxidation PS-PVD TBCs

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高校学生五育综合评价系统的设计与开发

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武夷学院学报 2024年第3期43卷 39-46页

作者：陈文龙漳州职业技术学院学生工作部福建省漳州市363000

为研究一套适合高校学生教育综合评价体系,创新学生德智体美劳过程性评价办法,通过基于微信小程序为载体,充分利用信息技术手段提高教育评价的科学性、专业性、客观性,通过整合育人资源、创新育人形式、强化育人过程,构建过程与结果并... 详细信息

为研究一套适合高校学生教育综合评价体系,创新学生德智体美劳过程性评价办法,通过基于微信小程序为载体,充分利用信息技术手段提高教育评价的科学性、专业性、客观性,通过整合育人资源、创新育人形式、强化育人过程,构建过程与结果并重、线上与线下相融、“五育并举”的立体化评价体系。研究设计德育、智育、体育、美育、劳动五个方面综合评价系统,以“五育”积分形式点滴记录学生的成长,高效科学的反映每个学生在厚德、启智、强体、悦美、尚劳等方面的实时发展情况。既能体现共性,又能体现学生能力水平及个人创造性。有效促进高校学生综合素质发展与提升,推进学校教育评价改革。

关键词：学生综合评价五育并举微信小程序应用系统教育评价改革

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Numerical Simulation of Dam-Break Flooding of Cascade Reservoirs

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Transactions of Tianjin University 2017年第6期23卷 570-581页

作者： Zhengyin Zhou Xiaoling Wang wenlong chen Shaohui Deng Minghui Liu Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China

Previous studies at home and abroad have mainly focused on single dam-break, and little attention has been paid so far to the dam-break of cascade reservoirs.Multi-source flooding, which can lead to three-dimensional turbulent phenomena and superposition effects, is the main difference between the dam-break of cascade and single reservoirs. Detailed descriptions of the coupled numerical simulation of multi-source flooding have little been reported, and the initial wet riverbed is rarely considered in current models. Therefore, in this paper, a method based on the three-dimensional k-ε turbulence model coupled with the volume-of-fluid method is proposed to simulate the dam-break flooding of cascade reservoirs. The upstream river, reservoir, and downstream river are connected by the internal boundary method, and the initial conditions,including river flow and reservoir water, are determined according to the results of the numerical simulation. Coupled numerical simulation of different dam-break flooding is then achieved. The present work solves the challenges presented by the enhancement and superposition of natural river flow, upstream flooding, and downstream flooding.This paper provides a theoretical basis for future studies on the dam-break flood routing of cascade reservoirs.

关键词： Dam-break Cascade reservoirs Multi-source flood Three-dimensional turbulence model

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