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外置转向架包覆对高速列车气动阻力影响

铁道科学与工程学报 2024年第1期21卷 26-37页

作者：邓海丁艳思向南燊项涛张洁梁习锋中南大学交通运输工程学院轨道交通安全教育部重点实验室湖南长沙410075 轨道交通列车安全保障技术国家地方联合工程研究中心湖南长沙410075 中车长春轨道客车股份有限公司总体研发部吉林长春130062

转向架作为高速列车大面积裸露在外且外形复杂的运行部件受到列车底部气流的直接作用,区域气动外形结构对高速列车整车气动阻力具有重要影响。基于三维稳态SST k-ω双方程湍流模型,采用数值仿真方法研究了轴箱外置式转向架不同包覆方式... 详细信息

转向架作为高速列车大面积裸露在外且外形复杂的运行部件受到列车底部气流的直接作用,区域气动外形结构对高速列车整车气动阻力具有重要影响。基于三维稳态SST k-ω双方程湍流模型,采用数值仿真方法研究了轴箱外置式转向架不同包覆方式对高速列车气动性能的影响。研究了转向架区域安装小裙板、半包裙板、全包裙板、全包裙板+小底板以及全包裙板+大底板等5种方案下的高速列车气动性能,比较了不同方案下高速列车气动阻力的变化规律,阐明了高速转向架包覆方式对整车气动阻力、车底流动特性以及列车表面压力分布的影响。研究结果表明:随着转向架裙板包覆面积的增加,转向架腔后端板受到的气流冲击逐渐减弱,后端板上的正压分布降低,列车转向架区域周围的边界层厚度逐渐减小,转向架区域内的压力分布差异性逐渐减小,从而实现了列车整车气动阻力系数的降低。与小裙板模型相比,半包裙板、全包裙板、全包裙板+小底板以及全包裙板+大底板模型的列车气动阻力系数分别降低了5.2%、8.65%、10.3%、11.1%。对于轴箱外置式转向架来说,全包裙板+大底板方案可有效改善转向架区域流场,降低整车气动阻力。研究得到的转向架包覆方式将为新一代高速列车气动减阻设计提供有利支撑,实现列车气动节能。

关键词：轴箱外置式转向架高速列车包覆方式气动减阻流场结构

基于拓扑优化和缩尺试验的小宽厚比独柱式桥墩帽梁力学性能研究

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公路交通科技 2024年第5期41卷 97-107页

作者：胡赛鸿常柱刚邓海波丁磊长沙市城市建设投资开发集团有限公司湖南长沙410007 长沙市规划设计院有限责任公司湖南长沙410007

由于小宽厚比独柱墩帽梁属于典型的应力扰动区构件,内部受力较为复杂,普通独柱墩帽梁的设计方法可能对其不适用。对小宽厚比独柱墩帽梁模型进行拓扑优化,分析小宽厚比独柱墩帽梁的空间受力特征,根据拓扑优化结果建立小宽厚比独柱墩帽梁... 详细信息

由于小宽厚比独柱墩帽梁属于典型的应力扰动区构件,内部受力较为复杂,普通独柱墩帽梁的设计方法可能对其不适用。对小宽厚比独柱墩帽梁模型进行拓扑优化,分析小宽厚比独柱墩帽梁的空间受力特征,根据拓扑优化结果建立小宽厚比独柱墩帽梁的空间拉压杆模型基本构形,并根据最小应变能准则提出了确定其最优构型的方法。针对目前对小宽厚比独柱墩帽梁试验研究较少的现状,进行缩尺模型试验,研究其竖向静载作用下的受力特性。结果表明:在横桥向,帽梁顶部在双支座荷载下具有最大拉应力;在顺桥向,帽梁中间位置拉应力最大,帽梁的顶部拉应力低于中部,帽梁底部则表现出受压的趋势。由于未考虑顺桥向的力流扩散,根据相关规范中拉压杆模型设计方法计算得到的内力值与试验结果相差较大,说明规范法不适用于小宽厚比独柱墩帽梁的设计。试验结果的应力分布情况与根据拓扑优化结果提出的空间拉压杆模型一致,并且采用空间拉压杆模型计算得到的拉杆应力值相比规范法更加合理,证明本研究所提的空间拉压杆模型基本构形以及确定最优构型方法的合理性。

关键词：桥梁工程小宽厚比独柱墩帽梁空间拉压杆模型拓扑优化缩尺模型试验

Vortex Quantum Droplets under Competing Nonlinearities

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Chinese Physics Letters 2024年第2期41卷 1-9页

作者：陈桂华王红成邓海明 Boris A.Malomed School of Electronic Engineering&Intelligentization Dongguan University of TechnologyDongguan 523808China School of Physics and Electronic-Electrical Engineering Xiangnan UniversityChenzhou 423000China Instituto de Alta Investigación Universidad de TarapacáCasilla 7DAricaChile

This concise review summarizes recent advancements in theoretical studies of vortex quantum droplets(VQDs)in matter-wave fields.These are robust self-trapped vortical states in two-and three-dimensional(2D and 3D)Bose–Einstein condensates(BECs)with intrinsic nonlinearity.Stability of VQDs is provided by additional nonlinearities resulting from quantum fluctuations around mean-field states,often referred to as the Lee–Huang–Yang(LHY)corrections.The basic models are presented,with emphasis on the interplay between the mean-field nonlinearity,LHY correction,and spatial dimension,which determines the structure and stability of VQDs.We embark by delineating fundamental properties of VQDs in the 3D free space,followed by consideration of their counterparts in the 2D setting.Additionally,we address stabilization of matter-wave VQDs by optical potentials.Finally,we summarize results for the study of VQDs in the single-component BEC of atoms carrying magnetic moments.In that case,the anisotropy of the long-range dipole-dipole interactions endows the VQDs with unique characteristics.The results produced by the theoretical studies in this area directly propose experiments for the observation of novel physical effects in the realm of quantum matter,and suggest potential applications to the design of new schemes for processing classical and quantum information.

关键词： quantum correction dipole

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复杂软土地质超深搅拌桩关键技术研究

水利建设与管理 2024年第2期44卷 22-26页

作者：邓海李登海中交上航华南市政工程有限公司广东珠海519199 中交上海航道局有限公司上海200002

超深搅拌桩桩底质量问题一直是地基基础加固处理中最难控制的质量问题,桩底遇特殊软土比遇普通软土成桩技术难度更大,质量风险更高。本文依托珠海乾务赤坎大联围斗门段防潮洪海堤提升工程,分别选用PH-5D型、DGN-28型搅拌设备进行现场试... 详细信息

超深搅拌桩桩底质量问题一直是地基基础加固处理中最难控制的质量问题,桩底遇特殊软土比遇普通软土成桩技术难度更大,质量风险更高。本文依托珠海乾务赤坎大联围斗门段防潮洪海堤提升工程,分别选用PH-5D型、DGN-28型搅拌设备进行现场试验及理论分析。结果表明:PH-5D型搅拌设备功率小,动力弱,采用多翼片钻头后,在超深软土内反而增加了一定阻力,不能正常提高钻速;而DGN-28型搅拌设备功率大,动力足,结合多翼片钻头应用后,发挥的优势和作用极为明显,在“复杂软土层”及“超深软土层”内的成桩质量均得到了一定保证。

关键词：复杂软土地质超深搅拌桩技术研究

Genomic scanning enabling discovery of a new antibacterial bicyclic carbamate-containing alkaloid

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Synthetic and Systems Biotechnology 2021年第1期6卷 12-19页

作者： Qing Fang Linrui Wu Caroline Urwald Morgane Mugat Shan Wang Kwaku Kyeremeh Carol Philips Samantha Law d Yongjun Zhou hai deng Marine Biodiscovery Centre Department of ChemistryUniversity of AberdeenMeston WalkAberdeenAB243UEScotlandUK ENSAIA 2 avenue de la forêt de Haye54505 vandoeuvre lès NancyFrance Department of Chemistry University of GhanaP.O.Box LG56Legon-AccraGhana NCIMB Ltd Ferguson BuildingCraibstone EstateBucksburnAberdeenAB219YAScotlandUK Research Centre for Marine Drugs State Key Laboratory of Oncogenes and Related GenesDepartment of PharmacyRen Ji HospitalSchool of MedicineShanghai Jiao Tong UniversityShanghai200127China

Non-ribosomal peptides are a group of structurally diverse natural products with various important therapeutic and agrochemical applications.Bacterial pyrrolizidine alkaloids(PAs),containing a scaffold of two fused five-membered ring system with a nitrogen atom at the bridgehead,have been found to originate from a multidomain non-ribosomal peptide synthetase to generate indolizidine intermediates,followed by multistep oxidation,catalysed by single Bayer-Villiger(BV)enzymes,to yield PA scaffolds.Although bacterial PAs are rare in natural product inventory,bioinformatics analysis suggested that the biosynthetic gene clusters(BGCs)that are likely to be responsible for the production of PA-like metabolites are widely distributed in bacterial genomes.However,most of the strains containing PA-like BGCs are not deposited in the public domain,therefore preventing further assessment of the chemical spaces of this group of bioactive metabolites.Here,we report a genomic scanning strategy to assess the potential of PA metabolites production in our culture collection without prior knowledge of genome information.Among the strains tested,we found fifteen contain the key BV enzymes that are likely to be involved in the last step of PA ring formation.Subsequently one-strain-many-compound(OSMAC)method,supported by a combination of HR-MS,NMR,SMART 2.0 technology,and GNPS analysis,allowed identification and characterization of a new[5+7]heterobicyclic carbamate,legoncarbamate,together with five known PAs,bohemamine derivatives,from Streptomyces sp.CT37,a Ghanaian soil isolate.The absolute stereochemistry of legoncarbamate was determined by comparison of measured and calculated ECD spectra.Legoncarbamate displays antibacterial activity against E.coli ATCC 25922 with an MIC value of 3.1μg/mL.Finally,a biosynthetic model of legoncarbamate and other bohemamines was proposed based on the knowledge we have gained so far.

关键词： Genomic scanning Bayer villiger monooxygenase Carbamate alkaloids Pyrrolizidine alkaloids Non-ribosomal peptide synthetases

Othogonal Waveform Design for Multiple-Input Multiple-Output (MIMO) Radar

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Open Journal of Applied Sciences 2012年第4期2卷 22-25页

作者： hai deng Department of Electrical and Computer Engineering Florida International University Miami Florida 33174 USA

An effective numerical approach is developed for orthogonal waveform design for Multiple-Input Multiple-Output (MIMO) radar. The Doppler shift tolerance is considered in the design cost function. The design results in... 详细信息

关键词： MIMO radar waveform design Doppler effect

Prevalence and modifiable risk factors of degenerative valvular heart disease among elderly population in southern China

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Journal of Geriatric Cardiology 2021年第7期18卷 523-533页

作者： Shang-Fei HE Jun-Rong JIANG Fang-Zhou LIU Hong-Tao LIAO Yu-Mei XUE Mu-Rui ZHENG Huo-Xing LI hai deng Shu-Lin WU South China University of Technology School of Medicine GuangzhouChina Department of Cardiology Guangdong Provincial People’s HospitalGuangzhouChina Guangzhou Center for Disease Control and Prevention GuangzhouChina Qinghai Province Cardio Cerebrovascular Disease Specialist Hospital XiningChina

Objective To investigate the prevalence and modifiable risk factors of degenerative valvular heart disease(DVHD)among elderly population in southern China.Methods A stratified multistage sampling method was used to recruit subjects.The contents of the survey included the questionnaire,laboratory examination,echocardiography,and other auxiliary examinations.The possible risk factors of DVHD were analyzed by logistic regression analysis.Results A total of 3538 subjects≥65 years of age were enrolled.One thousand three hundred and seven subjects(36.9%)were diagnosed with DVHD.Degenerative was the most common etiology of VHD.Prevalence of DVHD increased with advancing age.The prevalence of DVHD differed by living region(χ^(2)=45.594,P<0.001),educational level(χ^(2)=50.557,P<0.001),and occupation(χ^(2)=36.961,P<0.001).Risk factors associated with DVHD included age(two-fold increased risk for each 10-year increase in age),elevated level C-reactive protein(OR=1.346,95%CI:1.100-1.646),elevated level low density lipoprotein(OR=1.243,95%CI:1.064-1.451),coronary artery disease(OR=1.651,95%CI:1.085-2.513),smoking(OR=1.341,95%CI:1.132-1.589),and hypertension(OR=1.414,95%CI:1.221-1.638).Other significant risk factors included reduced or elevated level red blood cell(OR=1.347,95%CI:1.031-1.761;OR=1.599,95%CI:1.097-2.331;respectively),elevated level platelets(OR=1.891,95%CI:1.118-3.198),elevated level uric acid(OR=1.282,95%CI:1.112-1.479),and stroke(OR:1.738,95%CI=1.085-2.513).Conclusions The survey characterized the baseline conditions of DVHD cohort of elderly population in Guangzhou city.The established and emerging risk factors for DVHD may represent challenges and opportunities for therapy.

关键词： elevated degenerative occupation

Predictive value of red cell distribution width on left atrial thrombus or left atrial spontaneous echo contrast in patients with non-valvular atrial fibrillation

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Journal of Geriatric Cardiology 2018年第6期15卷 408-412页

作者： Xian-Zhang ZHAN Wei-Dong LIN Fang-Zhou LIU Yu-Mei XUE Hong-Tao LIAO Xin LI Xian-Hong FANG hai deng Jun HUANG Yang-Qiu LI Jo-Jo hai Hung-Fat Tse Shu-Lin WU Department of Hematology the First Affiliated Hospital Jinan University Guangzhou China Department of Cardiology Atrial Fibrillation Center Guangdong Cardiovascular Institute Guangdong General Hospital Guangdong Academy of Medical Sciences Guangzhou China Cardiology Division Department of Medicine Queen Mary Hospital the University of Hong Kong Hong Kong China Division of Cardiology Department of Medicine the University of Hong Kong Shenzhen Hospital Shenzhen China

ObjectiveTo 在左 atrial 血栓( LAT )或左 atrial 上评估红房间分发宽度( RDW )的预兆的价值在有纤维性颤动( AF ) .MethodsWe 考察了的非瓣膜的 atrial 的病人的自发的回响对比( LASEC )作为非瓣膜的 AF 被诊断并且经历了 transesopha... 详细信息

ObjectiveTo 在左 atrial 血栓( LAT )或左 atrial 上评估红房间分发宽度( RDW )的预兆的价值在有纤维性颤动( AF ) .MethodsWe 考察了的非瓣膜的 atrial 的病人的自发的回响对比( LASEC )作为非瓣膜的 AF 被诊断并且经历了 transesophageal echocardiography ( T )在里面的 692 个病人从2014年4月的广东心血管的研究所到2015年12月。基线临床的特征，血常规的实验室测试，心动电流描记器大小是 analyzed.ResultsEighty -- 四个病人在 T 下面与 LAT/LASEC 被检查。吝啬的 RDW 水平与 non-LAT/LASEC 病人相比在 LAT/LASEC 病人是显著地更高的(13.59%

关键词：纤维性价值预兆血栓宽度分发房间颤动

Comment on“Outcomes of curative liver resection for hepatocellular carcinoma in patients with cirrhosis”

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World Journal of Gastrointestinal Oncology 2022年第1期14卷 366-368页

作者： Xiao-Long Tang Yan-Dong Miao deng-hai Mi The First Clinical Medical College Lanzhou UniversityLanzhou 730000Gansu ProvinceChina The Second Department of Gastrointestinal Surgery Affiliated Hospital of North Sichuan Medical CollegeNanchong 637000Sichuan ProvinceChina Dean's Office Gansu Academy of Traditional Chinese MedicineLanzhou730000Gansu ProvinceChina

The present letter to the editor is in response to the research“Outcomes of curative liver resection for hepatocellular carcinoma in patients with cirrhosis”by Elshaarawy et al in World J Gastroenterol 2021;13(5):424–439.The preoperative assessment of the liver reserve function in hepatocellular carcinoma(HCC)patients with cirrhosis is crucial,and there is no universal consensus on how to assess it.Based on a retrospective study,Elshaarawy et al investigated the impact of various classical clinical indicators on liver failure and the prognosis after hepatectomy in HCC patients with cirrhosis.We recommend that we should strive to explore new appraisal indicators,such as the indocyanine green retention rate at 15 min.

关键词： ICG-R15 Hepatectomy Cirrhosis Hepatocellular carcinoma