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Development of RPA-Cas12a-fluorescence assay for rapid and reliable detection of human bocavirus 1

Animal Models and Experimental Medicine 2024年第2期7卷 179-188页

作者： Weidong Qian Xuefei Wang Ting Wang Jie Huang Qian Zhang yongdong li Si Chen School of Food and Biological Engineering Shaanxi University of Science and TechnologyXi'anP.R.China Department of Dermatology Huazhong University of Science and Technology Union Shenzhen HospitalShenzhenP.R.China Ningbo Municipal Center for Disease Control and Prevention NingboP.R.China Medical College of Shenzhen University ShenzhenP.R.China

Human bocavirus(HBoV)1 is considered an important pathogen that mainly affects infants aged 6–24 months,but preventing viral transmission in resource-limited regions through rapid and affordable on-site diagnosis of individuals with early infection of HBoV1 remains somewhat challenging.Herein,we present a novel faster,lower cost,reliable method for the detection of HBoV1,which integrates a recombinase polymerase amplification(RPA)assay with the CRISPR/Cas12a system,designated the RPA-Cas12a-fluorescence assay.The RPA-Cas12a-fluorescence system can specifically detect target gene levels as low as 0.5 copies of HBoV1 plasmid DNA per microliter within 40 min at 37℃without the need for sophisticated instruments.The method also demonstrates excellent specificity without cross-reactivity to non-target pathogens.Furthermore,the method was appraised using 28 clinical samples,and displayed high accuracy with positive and negative predictive agreement of 90.9%and 100%,respectively.Therefore,our proposed rapid and sensitive HBoV1 detection method,the RPA-Cas12a-fluorescence assay,shows promising potential for early on-site diagnosis of HBoV1 infection in the fields of public health and health care.The established RPA-Cas12a-fluorescence assay is rapid and reliable method for human bocavirus 1 detection.The RPA-Cas12a-fluorescence assay can be completed within 40 min with robust specificity and sensitivity of 0.5 copies/μl.

关键词： CRISPR-Cas12a detection human bocavirus 1 on-site diagnosis recombinase polymerase amplification

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Review of Three-phase Soft Switching Inverters and Challenges for Motor Drives

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CES Transactions on Electrical Machines and Systems 2024年第2期8卷 177-190页

作者： Haifeng Lu Qiao Wang Jianyun Chai yongdong li IEEE the Department of Electrical Engineering Tsinghua UniversityBeijing 100084China the School of Electrical Engineering Xinjiang UniversityUrumqi 830047China

For electric vehicles (EVs),it is necessary to improve endurance mileage by improving the efficiency.There exists a trend towards increasing the system voltage and switching frequency,contributing to improve charging speed and power density.However,this trend poses significant challenges for high-voltage and high-frequency motor controllers,which are plagued by increased switching losses and pronounced switching oscillations as consequences of hard switching.The deployment of soft switching technology presents a viable solution to mitigate these issues.This paper reviews the applications of soft switching technologies for three-phase inverters and classifies them based on distinct characteristics.For each type of inverter,the advantages and disadvantages are evaluated.Then,the paper introduces the research progress and control methods of soft switching inverters (SSIs).Moreover,it presents a comparative analysis among the conventional hard switching inverters (HSIs),an active clamping resonant DC link inverter (ACRDCli) and an auxiliary resonant commuted pole inverter (ARCPI).Finally,the problems and prospects of soft switching technology applied to motor controllers for EVs are put forward.

关键词： Soft switching inverters Zero-voltage switching Electric vehicles Motor drives

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Mesozoic uplift of the Dabashan and Micangshan-Hannan Dome in the South Qinling orogenic belt

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Science China Earth Sciences 2022年第3期65卷 426-436页

作者： yongdong li Xiong XIONG Yashan FENG School of Geophysics and Geomatics University of GeosciencesWuhan 430074China

The topographic evolution of continental orogens is important for understanding continental orogenic processes,geodynamic mechanisms,and climatic and environmental changes.The Qinling Orogen is a major orogenic belt in China,and its uplift history can provide insights into the tectonic configuration and geodynamics of China and East Asia.Previous studies have shown that the Dabashan and Micangshan-Hannan Dome(MHD)in the South Qinling orogenic belt were uplifted during the Mesozoic.However,the magnitude of the uplift remains unclear.In this study,using sedimentary records in the northern Sichuan Basin and lithospheric flexural modeling,we estimated the magnitude of Mesozoic uplift of the Dabashan and MHD,along with the effective elastic thickness(Te)of the Sichuan Basin.The Dabashan and MHD were uplifted by approximately 1220 and 880 m during the Middle Jurassic and Early Cretaceous,respectively.Therefore,we propose that the present-day elevation of the Dabashan and MHD is primarily the result of Mesozoic uplift.The differences in the duration and amount of uplift between different tectonic units indicate that the uplift processes and driving mechanisms in the South Qinling orogenic belt were different in the Mesozoic and Cenozoic.Mesozoic uplift was the result of convergence of the North China and South China blocks advanced from east to west,whereas Cenozoic uplift was driven by ongoing indentation of the Indian Plate into Eurasia from southwest to northeast.The lithospheric strength of the northern Sichuan Basin was weakened from the Middle Jurassic to Early Cretaceous,and Tedecreased from 73 to 57 km.This may have been caused by the flexure-related bending stresses in the lithosphere that developed due to the large topographic loading.

关键词： South Qinling orogenic belt Dabashan Micangshan-Hannan Dome Mesozoic Uplift

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Vector valley Hall edge solitons in the photonic lattice with type-Ⅱ Dirac cones

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Frontiers of physics 2022年第5期17卷 75-82页

作者： Yiqing Tian Yiqi Zhang yongdong li Milivoj RBelić Key Laboratory for Physical Electronics and Devices of the Ministry of Education&Shaanxi Key Lab of Information Photonic Technique School of Electronic and Information EngineeringXi’an Jiaotong UniversityXi’an 710049China Science Program Texas A&M University at QatarP.O.Box 23874 DohaQatar

Topological edge solitons represent a significant research topic in the nonlinear topological photonics.They maintain their profiles during propagation,due to the joint action of lattice potential and nonlinearity,and at the same time are immune to defects or disorders,thanks to the topological protection.In the past few years topological edge solitons were reported in systems composed of helical waveguide arrays,in which the time-reversal symmetry is effectively broken.Very recently,topological valley Hall edge solitons have been demonstrated in straight waveguide arrays with the time-reversal symmetry preserved.However,these were scalar solitary structures.Here,for the first time,we report vector valley Hall edge solitons in straight waveguide arrays arranged according to the photonic lattice with innate type-II Dirac cones,which is different from the traditional photonic lattices with type-I Dirac cones such as honeycomb lattice.This comes about because the valley Hall edge state can possess both negative and positive dispersions,which allows the mixing of two different edge states into a vector soliton.Our results not only provide a novel avenue for manipulating topological edge states in the nonlinear regime,but also enlighten relevant research based on the lattices with type-II Dirac cones.

关键词： valley Hall effect topological edge soliton photonic topological insulator

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Dynamic mechanisms controlling the topography of Longmenshan area

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Science China Earth Sciences 2020年第1期63卷 121-131页

作者： Yuan XIE yongdong li Xiong XIONG Hubei Subsurface Multi-Scale Imaging Key Laboratory Institute of Geophysics and GeomaticsChina University of Geosciences

The Longmenshan fault, which defines the eastern edge of the Tibetan Plateau, is one of the steepest margins of the plateau with a sharp elevation drop of about 4 km over a distance less than 100 km across the Longmenshan fault. The mechanism which is responsible for controlling and maintaining the elevation difference is highly debated. Using multiple observations including seismic velocity model, Moho depth, effective elastic thickness of the lithosphere, we conducted a quantitative study for elucidating the contributions from crust and lithospheric mantle by an integrated analysis of lithospheric isostasy and flexure. It is shown that the topography of the Longmenshan fault is supported by both lithospheric isostasy and flexure statically, and lower crustal channel flow and mantle convection dynamically. Different mechanisms have different weights for contribution to the topography of the Songpan-Ganzi block and the Sichuan Basin. The static and dynamic support contribute roughly the same to the topographic difference of ~4 km between the two sides of the Longmenshan fault. The static topographic difference of ~2 km is mainly resulted from the lithospheric isostasy, while the dynamic one of ~2 km is contributed by the uprising of the accumulated material in the lower crust beneath the Songpan-Ganzi block and the downward drag force caused by the upper mantle convection under the Sichuan Basin. It is thus suggested that the lower crustal flow and upper mantle convection are dynamic forces which should be taken into account in the studies on the dynamics in the Longmenshan and surrounding regions.

关键词： Topography Longmenshan fault zone lithospheric isostasy lithospheric flexure Dynamic topography

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一种基于耦合电感的高增益软开关谐振变换器

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电工技术学报 2024年第1期39卷 194-205页

作者：王哲李驰郑泽东李永东电力系统及发电设备控制和仿真国家重点实验室(清华大学) 北京100084

该文提出了一种具有高增益、软开关的新型谐振变换器。该谐振变换器使用耦合电感来提高电压增益,升压比不仅取决于占空比,还取决于耦合电感的变比,具有高增益的优点。此外,由于采用了有源钳位技术,漏感中的能量可以被回收利用,用来对开... 详细信息

该文提出了一种具有高增益、软开关的新型谐振变换器。该谐振变换器使用耦合电感来提高电压增益,升压比不仅取决于占空比,还取决于耦合电感的变比,具有高增益的优点。此外,由于采用了有源钳位技术,漏感中的能量可以被回收利用,用来对开关管的结电容充放电提供能量,从而实现软开关。由于采用了耦合电感,所提出的变换器可以在较低的开关管电压应力的情况下实现较高的输出电压,因此可以使用低导通电阻的低压器件,从而提升系统的效率。该文分析了该谐振变换器的工作原理,并推导了输出电压、关断电流应力等参数的解析表达式。在此基础上,从理论上分析了该变换器取得软开关的条件,并对该变换器的各个器件的电压电流应力进行分析,为器件选型提供了理论依据。最后,搭建1kW实验样机,针对该文提出的基于耦合电感的谐振变换器的高增益、软开关、低电压应力、高效率等性能进行了实验验证。通过实验得出所提出的拓扑可以在10倍增益的情况下达到最高97.5%的效率,表明所提拓扑的优越性。

关键词：耦合电感谐振变换器高增益软开关

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Rabi oscillations of azimuthons in weakly nonlinear waveguides

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Advanced Photonics 2020年第4期2卷 39-46页

作者： Kaichao Jin yongdong li Feng li Milivoj R.Belic Yanpeng Zhang Yiqi Zhang Xi’an Jiaotong University Key Laboratory for Physical Electronics and Devices of the Ministry of EducationXi’anChina Guangdong Xi’an Jiaotong University Academy FoshanChina Texas A&M University at Qatar Science ProgramDohaQatar

Rabi oscillation,an interband oscillation,describes periodic motion between two states that belong to different energy levels,in the presence of an oscillatory driving field.In photonics,Rabi oscillations can be mimicked by applying a weak longitudinal periodic modulation to the refractive index.However,the Rabi oscillations of nonlinear states have yet to be introduced.We report the Rabi oscillations of azimuthons—spatially modulated vortex solitons—in weakly nonlinear waveguides with different symmetries.The period of the Rabi oscillations can be determined by applying the coupled mode theory,which largely depends on the modulation strength.Whether the Rabi oscillations between two states can be obtained or not is determined by the spatial symmetry of the azimuthons and the modulating potential.Our results not only deepen the understanding of the Rabi oscillation phenomena,but also provide a new avenue in the study of pattern formation and spatial field manipulation in nonlinear optical systems.

关键词： Rabi oscillations azimuthons weak nonlinearity longitudinally periodic modulation

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Modulation and Voltage Balancing Control of Dual Five-level ANPC Inverter for Ship Electric Propulsion Systems

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Chinese Journal of Electrical Engineering 2021年第4期7卷 78-92页

作者： Xiaohui Xu Xingchi Song Kui Wang Nianzhou liu Wenfeng Long Zedong Zheng yongdong li Science and Technology on Ship Integrated Power System Technology Laboratory Wuhan Institute of Marine Electric PropulsionWuhan 430070China China State Key Laboratory of Power System Tsinghua UniversityBeijing 100084China

Open-end winding motors are used extensively in ship electric propulsion systems,in which medium-voltage high-power inverters are a critical component.To increase the system voltage and power density,a dual five-level active neutral-point clamped(ANPC)inverter is proposed herein to drive medium-voltage open-end winding motors for ship electric propulsion.Each phase of this inverter comprises two five-level ANPC bridges and all the phases are powered by a common direct-current link.A hybrid modulation method is proposed to control this inverter.The series-connected switches in all the five-level ANPC bridges are operated at the fundamental frequency,and the other switches are controlled with a phase-shifted pulse-width modulation(PWM),which can achieve a natural balance between the neutral-point voltage and flying capacitor voltages in a carrier period.A closed-loop capacitor voltage balancing method based on adjusting the duty ratios of the PWM signals is proposed.The neutral-point voltage and flying capacitor voltages can be controlled independently and balanced without affecting the output phase voltage.Simulation and experimental results are presented to demonstrate the validity of this method.

关键词： Multilevel inverter active neutral-point clamped(ANPC) capacitor voltage balance open-end winding motor drive

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Role of nitric oxide in biological effects of vascular endothelial growth factor

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Frontiers of Medicine 2009年第3期3卷 284-286页

作者： Qigong liU Yan ZENG Jiani liU Shan YE yongdong li Zaiying LU Department of Internal Cardiology Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China

To evaluate the role of nitric oxide in the biological effects of vascular endothelial growth factor(VEGF)and the possible mechanism of VEGF,the in vitro cultured vascular endothelial cells of rabbit aorta were divided into control group,VEGF-treated group and VEGF+N-nitro-L-arginine methyl ester(L-NAME)-treated group.The absorbance(A)value of vascular endothelial cells and the levels of prostaglandin(PGI2),endothelin-1(ET-1)and von Willebrand factor(vWF)in the supernatant were observed by water-soluble tetrazo-lium salt assay,radioimmunoassay and enzyme-linked immunosorbent assay.The A values and PGI2 in VEGF-treated group and VEGF+L-NAME-treated group were higher than those in control group(Pliferation and secretion of PGI2 and inhibit the secretion of ET-1 and vWF in vascular endothelial cells and that L-NAME could inhibit the effect of VEGF partially.Nitric oxide is an important mediator in the process of stimulating prolifera-tion and regulating secretion of vascular endothelial cells by VEGF.

关键词： vascular endothelial growth factor nitric oxide N-nitro-L-arginine methyl ester vascular endothelial cells

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“作家”身份的生成与新文学的发生

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东方论坛（青岛大学学报） 2024年第3期 83-95页

作者：包啟飞李永东西南大学文学院重庆400715

“谁是作家”“作家是什么”并非不言自明的问题,而是关涉到五四时期新文学倡导者有意建构的一套身份与价值观念体系。经由从“著作家”到“创作家”、从“文人”到“作家”的指称转换,以及现代文坛对超人情感和现代知识的强调,作家被... 详细信息

“谁是作家”“作家是什么”并非不言自明的问题,而是关涉到五四时期新文学倡导者有意建构的一套身份与价值观念体系。经由从“著作家”到“创作家”、从“文人”到“作家”的指称转换,以及现代文坛对超人情感和现代知识的强调,作家被赋予“感化读者”与“改进国家”的社会职能。“作家”的生成与判定有赖于现代读者的“发明”与现代文学机制的助推。现代“作家”身兼报刊编辑、文学批评家等多重身份,怀有“启蒙”与“救亡”的价值追求,带来了文学创作主体的现代转换。“作家”身份的生成与塑造反映了新文学发生的内在逻辑,也提供了一条反思当下作家观的有效途径。

关键词：作家新文学的发生著作家文人创作主体

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