简介:OnMarch26,2010anunderwaterexplosion(UWE)ledtothesinkingoftheROKSCheonan.TheofficialMultinationalCivilian-MilitaryJointInvestigationGroup(MCMJIG)reportconcludedthatthecauseoftheunderwaterexplosionwasa250kgnetexplosiveweight(NEW)detonationatadepthof69mfromaDPRK'CHT-02D'torpedo.KimandGitterman(2012a)determinedtheNEWandseismicmagnitudeas136kgatadepthofapproximately8mand2.04,respectivelyusingbasichydrodynamicsbasedontheoreticalandexperimentalmethodsaswellasspectralanalysisandseismicmethods.ThepurposeofthisstudywastoclarifythecauseoftheUWEviamoredetailedmethodsusingbubbledynamicsandsimulationofpropellersaswellasforensicseismology.Regardingtheobservedbubblepulseperiodof0.990s,0.976sand1.030swerefoundincaseofa136NEWatadetonationdepthof8musingtheboundaryelementmethod(BEM)and3Dbubbleshapesimulationsderivedfora136kgNEWdetonationatadepthof8mapproximately5mportsidefromthehullcenterline.Hereweshowthroughanalyticalequations,modelsand3Dbubbleshapesimulationsthatthemostprobablecauseofthisunderwaterexplosionwasa136kgNEWdetonationatadepthof8mattributabletoaROKlittoral'landcontrol'mine(LCM).
简介:2018年12月24日,国家发展改革委和交通运输部发布《国家物流枢纽布局和建设规划》(下称“《规划》”),提出到2020年布局建设30个左右国家物流枢纽;到2025年布局建设150个左右国家物流枢纽,推动全社会物流总费用与GDP的比率下降至12%左右;到2035年基本形成与现代化经济体系相适应的国家物流枢纽网络。《规划》规定了国家物流枢纽的6种类型,包括陆港型、港口型、空港型、生产服务型、商贸服务型和陆上边境口岸型。结合“十纵十横”交通运输通道和国内物流大通道基本格局,选择127个具备一定基础条件的城市作为国家物流枢纽承载城市,规划建设212个国家物流枢纽。