检索结果-南通市图书馆

BAS-PSO算法优化的无传感器轮毂电机转速控制

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

江苏理工学院学报 2024年第4期30卷 16-27页

作者：彭倩吴浪徐笑韩锋钢 mark Robinson 厦门理工学院机械与汽车工程学院福建厦门361024 福建省客车先进设计与制造重点实验室福建厦门361024 纽卡斯尔大学工程学院纽卡斯尔英国NE17RU

针对无位置传感器轮毂电机比例积分(Proportion Integration,PI)控制中常见的抗干扰能力差、计算量大、控制精度不高等问题,提出一种粒子群-天牛须(Beetle Antennae Search-Particle Swarm Optimization,BAS-PSO)算法,在模型参考自适应... 详细信息

针对无位置传感器轮毂电机比例积分(Proportion Integration,PI)控制中常见的抗干扰能力差、计算量大、控制精度不高等问题,提出一种粒子群-天牛须(Beetle Antennae Search-Particle Swarm Optimization,BAS-PSO)算法,在模型参考自适应系统(Model Reference Adaptive System,MRAS)观测电机转速与位置的基础上,实现转速控制器的PI参数自整定。建立永磁同步轮毂电机(Permanent Magnet Synchronous Motor,PMSM)的数学模型,以转速环传递函数的时间绝对误差积分指标(Integrated Time Absolute Error,ITAE)作为适应度函数,通过BAS-PSO算法优化转速控制器的PI参数;MRAS将电机本身作为参考模型,将含有待估计参数的定子电流方程作为可调模型,基于Popov超稳定理论,设计合适的自适应律,估计电机的转速与位置;利用Matlab/Simulink进行仿真对比,并在HIL平台进行硬件测试验证。结果表明:与传统方法相比,BAS-PSO算法能够提高电机的运行响应速度,降低转速超调量,提高系统的鲁棒性。

关键词：轮毂电机模型参考自适应系统 BAS-PSO算法无位置传感器

Characterization of the gas pulse frequency,amplitude and velocity in non-steady dense phase pneumatic conveying of powders

在线全文

学校读者我要写书评

暂无评论

Particuology 2008年第5期6卷 301-306页

作者： Kenneth C.Williams mark g.Jones Ahmed A.Cenna Centre for Bulk Solids and Particulate Technologies School of EngineeringUniversity of Newcastle

Current modelling techniques for the prediction of conveying line pressure drop in low velocity dense phase pneumatic conveying are largely based on steady state analyses. Work in this area has been on-going for many years with only marginal improvements in the accuracy of prediction being achieved. Experimental and theoretical investigations undertaken by the authors suggest that the flow mechanisms involved in dense phase conveying are dominated by transient effects rather than those of steady state and are possibly the principal reasons for the limited improvement in accuracy. This paper reports on investigations on the pressure fluctuation behaviour in dense phase pneumatic conveying of powders. The pressure behaviour of the gas flow in the top section of the pipeline was found to exhibit pulsatile oscillations. In particular, the pulse velocity showed variation in magnitude while the frequency of the oscillations rarely exceeded 5 Hz. A wavelet analysis using the Daubechie 4 wavelet found that the amplitude of the oscillations increased along the pipeline. Furthermore, there was significant variation in gas pulse amplitude for different types of particulate material.

关键词： Pneumatic conveying Powders Dense phase Pulsatile flow Transient flow

在线全文

学校读者我要写书评

暂无评论

2024年别跟美联储作对

商业周刊（中文版） 2024年第1期 6-7页

作者： mark gilbert Marcus Ashworth 逸思(译) 不详

几年来的消费价格升,使通胀率远超美联储的目标值,从而促成了连串加息。然而,在急于为其货币稳定守护者的形象重新正名的同时,决策者的热情也有可能破坏经济增长并引发失业。我们预计,紧随近几个月加息暂停而来的将是政策的放松。无论如... 详细信息

几年来的消费价格升,使通胀率远超美联储的目标值,从而促成了连串加息。然而,在急于为其货币稳定守护者的形象重新正名的同时,决策者的热情也有可能破坏经济增长并引发失业。我们预计,紧随近几个月加息暂停而来的将是政策的放松。无论如何,美联储接下来的行动对于金融市场新一年表现的决定作用将比以往任何时候都重要。

关键词：加息金融市场消费价格通胀率美联储守护者目标值

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

纪念苏珊·沃西基互联网经济的推动者

商业周刊（中文版） 2024年第13期 18-20页

作者： mark Bergen Ros Krasny 孟洁冰(译) 不详

沃西基是硅谷最受瞩目的女高管之一,正是她塑造了在互联网上创造财富和名望的方式.谷歌(google)元老级高管、担任视频平台YouTube首席执行官多年的苏珊·沃西基(Susan Wojcicki)去世,终年56岁,正是她塑造了在互联网上创造财富和名望的... 详细信息

沃西基是硅谷最受瞩目的女高管之一,正是她塑造了在互联网上创造财富和名望的方式.谷歌(google)元老级高管、担任视频平台YouTube首席执行官多年的苏珊·沃西基(Susan Wojcicki)去世,终年56岁,正是她塑造了在互联网上创造财富和名望的方式。

关键词：首席执行官互联网元老级视频平台高管创造财富

Radical innovation breakthroughs of biodegradation of plastics by insects:history,present and future perspectives

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2024年第6期18卷 127-165页

作者： Shan-Shan Yang Wei-Min Wu Federica Bertocchini mark Eric Benbow Suja P.Devipriya Hyung Joon Cha Bo-Yu Peng Meng-Qi Ding Lei He Mei-Xi Li Chen-Hao Cui Shao-Nan Shi Han-Jun Sun Ji-Wei Pang Defu He Yalei Zhang Jun Yang Deyi Hou De-Feng Xing Nan-Qi Ren Jie Ding Craig S.Criddle State Key Laboratory of Urban Water Resource and Environment School of EnvironmentHarbin Institute of TechnologyHarbin 150090China Department of Civil and Environmental Engineering William&Cloy Codiga Resource Recovery CenterStanford UniversityStanfordCA 94305USA Plasticentropy rue Thiers 28Reims 51100France Department of Entomology and Department of Osteopathic Medical Specialties Michigan State UniversityEast LansingMI 48824USA School of Environmental Studies Cochin University of Science and TechnologyKochi 682022India Department of Chemical Engineering Pohang University of Science and TechnologyPohang 37673Republic of Korea School of Environmental Science and Engineering Tongji UniversityShanghai 200092China China Energy Conservation and Environmental Protection group CECEP Talroad Technology Co.Ltd.Beijing 100096China School of Ecological and Environmental Sciences East China Normal UniversityShanghai 200241China Research Institute for Frontier Science Beihang UniversityBeijing 100191China School of Environment Tsinghua UniversityBeijing 100084China

Insects damaging and penetrating plastic packaged materials has been reported since the *** innovation breakthroughs of plastic biodegradation have been initiated since the discovery of biodegradation of plastics by Tenebrio molitor larvae in 2015 followed by galleria mellonella in *** we review updated studies on the insect-mediated biodegradation of *** biodegradation by insect larvae,mainly by some species of darkling beetles(Tenebrionidae)and pyralid moths(Pyralidae)is currently a highly active and potentially transformative area of *** the past eight years,publications have increased explosively,including discoveries of the ability of different insect species to biodegrade plastics,biodegradation performance,and the contribution of host and microbiomes,impacts of polymer types and their physic-chemical properties,and responsible enzymes secreted by the host and gut *** date,almost all major plastics including polyethylene(PE),polypropylene(PP),polyvinyl chloride(PVC),polyethylene terephthalate(PET),polyurethane(PUR),and polystyrene(PS)can be biodegraded by *** and ten other insect species representing the Tenebrionidae and Pyralidae *** biodegradation processes are symbiotic reactions or performed by synergistic efforts of both host and gut-microbes to rapidly depolymerize and biodegrade plastics with hourly *** digestive ezymens and bioreagents screted by the insects play an essential role in plasatic biodegradation in certain species of Tenebrionidae and Pyralidae *** research on the insect itself,gut microbiomes,transcriptomes,proteomes and metabolomes has evaluated the mechanisms of plastic biodegradation in *** conclude this review by discussing future research perspectives on insect-mediated biodegradation of plastics.

关键词： Plastics Biodegradation Insects gut microbiomes Enzymes

Anti-N-methyl-D-aspartate receptor-associated encephalitis: A review of clinicopathologic hallmarks and multimodal imaging manifestations

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Radiology 2024年第1期16卷 1-8页

作者： Bryce David Beutler Alastair E Moody Jerry Mathew Thomas Benjamin Phillip Sugar mark B Ulanja Daniel Antwi-Amoabeng Lucas Anthony Tsikitas Department of Radiology University of Southern CaliforniaKeck School of MedicineLos AngelesCA 90033United States Department of Anesthesiology University of UtahSalt Lake CityUT 84132United States Department of Internal Medicine Christus Ochsner St.Patrick HospitalLake CharlesLA 70601United States

Anti-N-methyl-D-aspartate receptor-associated encephalitis(NMDARE)is a rare immune-mediated neuroinflammatory condition characterized by the rapid onset of neuropsychiatric symptoms and autonomic *** mechanism of pathogenesis remains incompletely understood,but is thought to be related to antibodies targeting the gluN1 subunit of the NMDA receptor with resultant downstream dysregulation of dopaminergic *** adults are most frequently affected;the median age at diagnosis is 21 *** is a strong female predilection with a female sex predominance of 4:*** often develops as a paraneoplastic process and is most commonly associated with ovarian ***,NMDARE has also been described in patients with small cell lung cancer,clear cell renal carcinoma,and other benign and malignant *** is based on correlation of the clinical presentation,electro-encephalography,laboratory studies,and *** tomography,positron emission tomography,and magnetic resonance imaging are essential to identify an underlying tumor,exclude clinicopathologic mimics,and predict the likelihood of long-term functional *** imaging may be of value for prognostication and to assess the response to *** may involve high-dose corticosteroids,intravenous immunoglobulin,and plasma ***,we review the hallmark clinicopathologic features and imaging findings of this rare but potentially devastating condition and summarize diagnostic criteria,treatment regimens,and proposed pathogenetic mechanisms.

关键词： Anti-N-methyl-D-aspartate receptor-associated encephalitis Autoimmune encephalitis Encephalitis Ovarian teratoma Paraneoplastic syndrome Teratoma

A qualitative study on the pulsatile flow phenomenon in a dense fly ash pneumatic conveyor

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2014年第6期12卷 81-91页

作者： Wei Chen Kenneth C.Williams Isabel Jabs mark g.Jones Centre for Bulk Solids and Particulate Technologies Newcastle Institute for Energy and ResourcesThe University of Newcastle Faculty of Mechanical Engineering Leibniz University of Hanover

Understanding of the dynamic particulate flow structures within a dense gas-fly ash pneumatic conveyor must be improved in order to better aid its design *** complex pulsatile movement of the gas-fly ash mixture dominates the flow performance within the pipeline,and historically,non-invasive measurement devices such as the electrical capacitance tomography（ECT） were often used to sufficiently capture the flow ***,inadequate studies have been conducted on the pulsatile flow phenomenon,which directly relate to the gas-fly ash two-phase flow *** paper aims to investigate the pulsatile flows using an ECT ***,pulsatile flow patterns under various experimental conditions were obtained through *** within a flow were then characterised into pulse growth and decay segments,which represent the superficial fluidisation and deaeration processes during ***,structural and statistical analyses were performed on the pulse growth and decay *** suggested that the increasing air mass flow rate led to the decrease of the superficial fluidisation/deaeration magnitude,however,the increase of the superficial fluidisation/deaeration ***,the air mass flow rate was indicated as the dominant factor in determining the pulsing statistical *** research provides fundamental insights for further modelling the dense fly ash pneumatic flows.

关键词： Pneumatic conveying Electrical capacitance tomography Fly ash Pulsatile flows Flow pattern analysis

Function of longitudinal vs circular muscle fibers in esophageal peristalsis, deduced with mathematical modeling

在线全文

学校读者我要写书评

暂无评论

World Journal of gastroenterology 2007年第9期13卷 1335-1346页

作者： James g Brasseur mark A Nicosia Anupam Pal Larry S Miller Department of Mechanical Engineering Pennsylvania State UniversityUniversity Park PA 16802United States Department of Mechanical Engineering Widener University ChesterPA 19013 United States Department of Biological Sciences & Bio-engineering Indian Institute of Technology Kanpur UP 208016 India Department of gastroenterology Temple University Medical CenterPhiladelphiaPA 19140United States

We summarize from previous works the functions of circular vs. longitudinal muscle in esophageal peristaltic bolus transport using a mix of experimental data, the conservation laws of mechanics and mathematical modeling. Whereas circular muscle tone generates radial closure pressure to create a local peristaltic closure wave, longitudinal muscle tone has two functions, one physiological with mechanical implications, and one purely mechanical. Each of these functions independently reduces the tension of individual circular muscle fibers to maintain closure as a consequence of shortening of longitudinal muscle locally coordinated with increasing circular muscle tone. The physiological function is deduced by combining basic laws of mechanics with concurrent measurements of intraluminal pressure from manometry, and changes in cross sectional muscle area from endoluminal ultrasound from which local longitudinal shortening (LLS) can be accurately obtained. The purely mechanical function of LLS was discovered from mathematical modeling of peristaltic esophageal transport with the axial wall motion generated by LLS. Physiologically, LLS concentrates circular muscle fibers where closure pressure is highest. However, the mechanical function of LLS is to reduce the level of pressure required to maintain closure. The combined physiological and mechanical consequences of LLS are to reduce circular muscle fiber tension and power by as much as 1/10 what would be requiredfor peristalsis without the longitudinal muscle layer, a tremendous benefit that may explain the existence of longitudinal muscle fiber in the gut. We also review what is understood of the role of longitudinal muscle in esophageal emptying, reflux and pathology.

关键词： Esophagus Longitudinal muscle Circular muscle Longitudinal shortening Peristalsis

Protecting miners from coal bursts during development above historic mine workings in Harlan County,KY

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2021年第1期31卷 111-116页

作者： Christopher mark Mine Safety and Health Administration PittsburghPA 15236USA

In order to reach a large,untapped reserve of high-quality coal,D8 Cloverlick Mine proposed to mine a corridor nearly 600 m deep beneath the Benham Spur of Black Mountain,Kentucky’s highest peak.D8 Cloverlick Mine was extracting the Owl seam,but the corridor’s route lay approximately 20 m above century-old mine workings in the C–(Darby)*** to the concern,three serious coal bursts had recently occurred in nearby Owl seam *** of the old workings seemed to indicate that the underlying C–seam had been fully ***,two of the coal bursts had occurred above areas where the C–Seam was also shown as mined *** Safety and Health Administration(MSHA)Technical Support therefore investigated the records of past mining to better understand the old mine *** conditions observed in current Owl seam workings were also compared with the maps of the old C–seam *** study concluded that the presence of hazardous underlying remnants could not be ruled *** mitigate the burst risk,D8 Cloverlick Mine adopted a strategy of stress probe drilling.A self-propelled coal drill was used to auger 11.5-m-long,small diameter holes in advance of *** each hole was drilled,the cuttings were measured to detect the presence of highly stressed *** the crossing was successfully completed without incident.

关键词： Coal bursts Underground mining Room-and-pillar Destressing