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Experimental Study on Vortex-Induced Vibration of Rough Risers Coupling with Interference Effect in Tandem Arrangement

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China Ocean Engineering 2024年第3期38卷 394-407页

作者： HU Ze-bo LIU Zhen LI Peng GUO Hai-yan ren Xiao-hui HOU hao hao Lian-hong College of Civil Engineering and Architecture Shandong University of Science and TechnologyQingdao 266590China Qingdao Key Laboratory of Marine Civil Engineering Materials and Structures Qingdao 266590China College of Engineering Ocean University of ChinaQingdao 266100China

In order to study the response law of vortex-induced vibration(VIV)of marine risers under the combined action of roughness and interference effects,and to reveal the coupling mechanism of roughness and interference effects on the riser,a VIV experiment of rough risers in tandem arrangement was conducted in a wave−current combined *** experiment characterized the risers’roughness by arranging different specifications of attachments on the surface of the *** rough risers with different roughness and smooth risers were arranged in tandem arrangement,with the rough risers arranged *** experimental results indicate that the suppression of the attachments on the downstream risers’vibration are more significant both in the CF and IL directions as the reduced velocity *** the downstream riser,the amplitude response of rough riser is more significantly weakened compared with the smooth one at high reduced *** the upstream risers,changes in the roughness and spacing ratio have an impact on their‘lock-in’*** the roughness of downstream risers is relatively large(0.1300)and the spacing between risers is small(S/D=4.0),the reduced velocity range of‘lock-in’region in the CF direction of upstream risers is obviously expanded,and the displacement in the‘lock-in’region is severer.

关键词： marine riser vortex-induced vibration tandem arrangement roughness interference effect

Numerical Investigation on Vortex-Induced Rotations of A Triangular Cylinder Using An Immersed Boundary Method

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China Ocean Engineering 2019年第6期33卷 723-733页

作者： WANG Hua-kun yan Yu-hao CHEN Can-ming JI Chun-ning ZHAI Qiu Jiangsu Key Laboratory of Coast Ocean Resources Development and Environment Security College of HarbourCoastal and Offshore EngineeringHohai UniversityNanjing 210098China State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China Key Laboratory of Water Science and Water Engineering of Ministry of Water Resources Nanjing Hydraulic Research InstituteNanjing 210029China

A numerical study of vortex-induced rotations(VIRs) of an equivalent triangular cylinder, which is free to rotate in the azimuthal direction in a uniform flow, is presented. Based on an immersed boundary method, the numerical model is established, and is verified through the benchmark problem of flow past a freely rotating rectangular *** computation is performed for a fixed reduced mass of m~*=2.0 and the structural stiffness and damping ratio are set to zero. The effects of Reynolds number(Re=25-180) on the characteristics of VIR are studied. It is found that the dynamic response of the triangular cylinder exhibits four distinct modes with increasing Re: a rest position,periodic rotational oscillation, random rotation and autorotation. For the rotational oscillation mode, the cylinder undergoes a periodic vibration around an equilibrium position with one side facing the incoming flow. Since the rotation effect, the outset of vortex shedding from cylinder shifts to a much lower Reynolds number. Further increase in Re leads to 2 P and P+S vortex shedding modes besides the typical 2 S pattern. Our simulation results also elucidate that the free rotation significantly changes the drag and lift forces. Inspired by these facts, the effect of free rotation on flow-induced vibration of a triangular cylinder in the in-line and transverse directions is investigated. The results show that when the translational vibration is coupled with rotation, the triangular cylinder presents a galloping response instead of vortex-induced vibration(VIV).

关键词： vortex-induced rotation triangular cylinder dynamic response vortex shedding mode immersed boundary method

Novel assisted cough system based on simulating cough airflow dynamics

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Bio-Design and Manufacturing 2021年第3期4卷 479-489页

作者： Shuai ren Jinglong Niu Maolin Cai Liming hao yan Shi Weiqing Xu Zujin Luo School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou 310027China North Automatic Control Technology Institute Taiyuan 030006China Department of Respiratory and Critical Care Medicine Beijing Engineering Research Center of Respiratory and Critical Care MedicineBeijing Institute of Respiratory MedicineBeijing Chao-Yang HospitalCapital Medical UniversityBeijing 100043China

Cough is a defensive behavior that protects the respiratory system from infection and clears airway *** airflow dynamics have been analyzed by a variety of mathematical and experimental *** this paper,the cough airflow dynamics of 42 subjects were obtained and *** identification model based on piecewise Gauss function for cough airflow dynamics is proposed through the dimensionless method,which could achieve over 90%identification ***,an assisted cough system based on pneumatic flow servo system is *** vacuum situation and feedback control are used to increase the simulated peak cough flow rate,which are important for airway secretion clearance and to avoid airway collapse,*** simulated cough peak flow could reach 5 L/s without the external assistance such as manual pressing,patient cooperation and other ***,the backstepping control is developed to generate a simulated cough airflow that closely mimics the natural cough airflow of *** assisted cough system opens up wide opportunities of practical application in airway secretion clearance for critically ill patients with COVID 2019 and other pulmonary diseases.

关键词： Airflow dynamics Pneumatic system Simulated cough Model identification Airway secretion clearance

Preparation, Crystal Structure and Thermal Decomposition Process of Dysprosium Benzoate Complex with 1,10-Phenanthroline

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Chinese Journal of Structural Chemistry 2008年第2期27卷 233-237页

作者： XU Su-Ling ZHANG Jian-Jun ren ning ZHANG Hai-yan HU Rui-Sheng Experimental Center Hebei Normal UJziversity Shijiazhuang 050016 China Department of Engineering Shijiazhuang Foreign Economy and Trade Vocational College Shijiazhuang 050061 China Department of Chemistry Handan College Handan 056005 China School of Chemical Engineering Shijiazhuang College Shijiazhuang 050035 China

A dinuclear dysprosium（III） complex with benzoic acid and 1,10-phenanthroline, [Dy（BA）3phen]2 （BA = benzoate, PHEN = 1,10-phenanthroline）（C66H46Dy2NaO12, Mr = 1412.07） was synthesized and characterized by elemental analysis, UV, IR, X-ray diffraction, molar conductance and TG-DTG techniques. It crystallizes in triclinic, space group P1 with a = 10.773（2）, b = 11.933（3）, c = 12.417（5） A, α= 105.226（3）,β= 93.470（3）, γ= 113.475（2）°, V= 1388.0（7）, Z = 1, Dc = 1.689 g/cm3, μ（MoKa） = 2.742 mm-1 and F（000） = 698. R = 0.0210, wR = 0.0538. In the crystal, each Dy（III） ion is eight-coordinated by one bidentate chelating carboxylate group, four bidentate bridging carboxylate groups and one 1,10-phenanthroline molecule. The thermal decomposition process of [Dy（BA）3phen]2 has been determined by thermal analysis.

关键词： benzoic acid crystal structure 1,10-phenanthroline dysprosium complex thermal analysis

Twinned substructure in lath martensite of water quenched Fe-0.2%C and Fe-0.8%C steels

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Journal of Materials Science & Technology 2020年第14期47卷 126-132页

作者： Haidong Sun Yuhui Wang Zuohua Wang ning Liu yan Peng Xiujuan Zhao Ruiming ren Hongwang Zhang National Engineering Research Center for Equipment and Technology of Cold Strip Rolling College of Mechanical EngineeringYanshan UniversityQinhuangdao066004China Liren College of yanshan University Yanshan UniversityQinhuangdao066004China School of Materials Science&Engineering Dalian Jiaotong UniversityDalian116028China

In the present investigation,twinned substructures within lath martensite of two water quenched steels(0.2 wt.%C and 0.8 wt.%C)were *** lath martensite has typical hierarchical packet-block-lath with dislocation ***,laths that are misoriented by/70.5°or/60° and bordered by{011}plane,namely twinned laths,are observed,of which the density increases and the scale decreases as more carbons were *** twinned laths have body centered cubic(bcc)crystal structure,belonging to twinned variants following the classical Kurdjumov-Sachs(K-S)orientation relationship with respect to the parent *** bcc{112}twins,twinned variants produce strong double diffraction and in turn the extra diffraction spots that are commonly observed in the martensite in steels with wide range of carbon contents.

关键词： Twinned variant Lath martensite Double electron diffraction Orientation relationship Steels

Controllable combustion behaviors of the laser-controlled solid propellant

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Defence Technology（防务技术） 2022年第1期18卷 38-48页

作者： Bu-ren Duan hao-nan Zhang Li-zhi Wu Zuo-hao Hua Zi-jing Bao ning Guo Ying-hua Ye Rui-qi Shen School of Chemical Engineering Narging University of Science and Technology Narjing 210094China Instifute of Space Propulsion Nanjing University of Science and Technology Nanjing 210094China Micro-Nano Energetic Devices Key Laboratory Ministry of Industry and Informnation TedhinologyNanjing210094China Shanghai Space Propulsion Technology Research Instirute Shanghai201109China

Microsatellites have been widely applied in the fields of communication,remote sensing,navigation and science exploration due to its characteristics of low cost,flexible launch mode and short development ***,conventional solid-propellant have difficulties in starting and interrupting combustion because combustion is autonomously sustained after ignition Herein,we proposed a new type of solid-propellant named laser-controlled solid propellant,which is sensitive to laser irradiation and can be started or interrupted by switching on/off the continuous wave *** demonstrate the feasibility and investigate the controllable combustion behaviors under different laser on/off conditions,the combus tion parameters including burning rate,ignition delay time and platform pressure were tested using pressure sensor,high-speed camera and thermographic *** results showed that the increase of laser-on or laser-off duration both will lead to the decrease of propellant combustion performance during re-ignition and re-combustion *** is mainly attributed to the laser attenuation caused by the accumulation of combustion residue and the change of chamber ambient *** the multiple ignition tests revealed that the increased chamber ambient temperature after combustion can make up for the energy loss of laser attenuation and expansion of chamber ***,the laser-controlled combustion performance of solid propellant displayed a decrease trend with the addi-tion of ignition ***,the results still exchibited good laser-controlled agility of laser-controlled solid propellant and manifested its inspiring potential in many aspects of space missions.

关键词： Laser-con trolled solid propellant Laser ablation Multiple ignition Controllable combustion Combustion be haviors

An acquisition system of digital nuclear signal processing for the algorithm development

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Nuclear Science and Techniques 2013年第6期24卷 115-121页

作者： WANG Peng ZHANG Ruanyu yan yangyang hao Dejian HUANG ning WU Qingxing AN Zhu Institute of Nuclear Science and Technology of Sichuan University Key Laboratory of Radiation Physics and TechnologyMinistry of Education The College of Physics Science and Technology of Sichuan University

A principle and method of constructing the digital acquisition system is presented in this work,which is convenient for the study on the theories and algorithms of digital nuclear signal *** hardware system of the digital acquisition system consists of front-end controller,waveform digitizer and PC workstation,on which the software system has been developed based on Visual C++under Windows *** alterable-frequency sampling(AFS)algorithm and the alterable-frequency trapezoidal filter(AFTF)algorithm have also been studied in the real-time environment,along with a digital nuclear spectrum acquisition system being set up based on the new algorithms and theγ-ray spectra of 241Am being shown.A useful experimental platform could be provided by this work for the successive work such as the development of global digitized nuclear measurement system and the study of digital nuclear signal processing.

关键词：数字信号处理数字采集系统研究开发算法 Windows环境波形数字转换器可变频率前端控制器

High-resolution gene profiling of infection process indicates serine metabolism adaptation of Fusarium graminearum in host

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Science Bulletin 2017年第11期62卷 758-760页

作者： Qing-ning Xie Lei-Jie Jia yan-Zhang Wang ren-Tao Song Wei-Hua Tang School of Life Sciences Shanghai University National Key Laboratory of Plant Molecular Genetics CAS Center for Excellence in Molecular Plant SciencesInstitute of Plant Physiology and EcologyShanghai Institutes for Biological SciencesChinese Academy of Sciences

Fusarium graminearum,an important fungal pathogen,can cause head blight,seedling blight and crown rot on wheat(Triticum aestivum),stalk rot and ear rot on maize(Zea mays)[1,2].Annually,billions of dollars are lost wor... 详细信息

关键词：禾谷镰刀菌感染过程基因分析高分辨率酸代谢脱氧雪腐镰刀菌烯醇菌丝宿主

Prediction of miRNA Based on miRNA Biogenesis via One-class SVM

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Chemical Research in Chinese Universities 2010年第5期26卷 803-809页

作者： LIU Yuan-ning yan Wen ZHANG hao LI Zhi LU Hui-jun LI Xin College of Computer Science and Technology Symbol Computation and Knowledge Engineering of Ministry of Education Jilin University Changehun 130012 P. R. China Institute of Military Veterinary Academy of Military Medical Sciences Changchun 130012 P. R. China Changchun University of Science ＆ Technology Changchun 130022 P. R. China

MicroRNAs are a class of small, single-stranded RNAs which are produced by non-protein-coding RNA genes with a length of 21-29 nt. They regulate the expression of protein-encoding genes at the post-transcriptional level and the degradation ofmRNAs by base pairing to mRNAs. Mature miRNAs are processed from 60-90 nt RNA hairpin structures called pre-miRNAs. At present, most of the machine learning computational methods for pre-miRNAs prediction are based on two-class SVM and use structural information of pre-miRNA hairpins. Those methods share a common feature that all of them need a negative dataset in the training dataset and feature selection in both training and testing dataset. In order to avoid selecting false negative examples of miRNA hairpins in the training dataset which may mislead the classifiers, we presented a microRNA prediction algorithm called MirBio based on miRNAs Biogenesis which is trained only on the information of the positive miRNAs class to predict miRNAs. It can predict both pre-miRNAs and miRNAs and get a relatively satisfying result in this study.

关键词： miRNAs Hairpin One-class classification miRNAs Biogenesis