This paper describes the electric drive for an in-wheel fractional-slot axial flux machine,designed for achieving a wide flux-weakening operating region.By using a slotted stator with fractional-slot windings and addi...This paper describes the electric drive for an in-wheel fractional-slot axial flux machine,designed for achieving a wide flux-weakening operating region.By using a slotted stator with fractional-slot windings and additional cores enclosing end windings,the axial flux machine reaches a wide constant power speed range.The machine is designed for increasing flux-weakening capability while obtaining low harmonic back-electromotive force and low cogging torque.A 10 N.m axial flux machine exhibiting 3 to 1 flux-weakening speed range has been built.A flux-weakening controller,able to maximize the output torque in the flux-weakening region,is designed and implemented.The goodness of both design and control algorithm is proved by experimental tests.However,such a fractional-slot machine has not only advantages.Rotor losses are very high,and they have to be properly considered during the design process.展开更多
Graphene oxide(GO)as a new nano-enhancer in cement-based materials has gained wide attention.However,GO is easy to aggregate in alkaline cement mortar with poor dispersibility.This hinders its application in practical...Graphene oxide(GO)as a new nano-enhancer in cement-based materials has gained wide attention.However,GO is easy to aggregate in alkaline cement mortar with poor dispersibility.This hinders its application in practical infrastructure construction.In this work,GO-M18 polycarboxylate compound superplasticizer(GM)were obtained by compounding the M18 polycarboxylate superplasticizer with GO solution at different mass ratios.The dispersion of GM in alkaline solution was systematically studied.The phases and functional groups of GM were characterized by XRD and FTIR.The effects of GM on the cement mortar hydration and the formation of microstructure were investigated by measuring the heat of hydration,MIP,TG/DSC,and SEM.The results show that the long-chain structure of the M18 polycarboxylate superplasticizer can increase the interlayer spacing of GO and weaken the force between GO sheets.The modified GO can be uniformly dispersed in the cement slurry.GM can accelerate the early hydration process of cement,which can increase the content of Ca(OH)2 and decrease the grain size.It can optimize the pore size distribution of cement-based materials,increase the density of harmless and less harmful pores,thereby improving mechanical properties.Such methods can transform traditional cement-based materials into stronger,more durable composites,which prolong the life of cement-based materials and reduce the amount of cement used for later maintenance.This provides an idea for achieving sustainability goals in civil engineering.展开更多
随着各种医用加速器新技术的提高和肿瘤患者数量的急剧增加,放射治疗已经成为治疗肿瘤的主要手段之一。医用加速器技术的不断进步,始终围绕着照射肿瘤的同时最大限度地保护正常器官而发展,但仍无法解决由于高能射线在治疗患者时所带来...随着各种医用加速器新技术的提高和肿瘤患者数量的急剧增加,放射治疗已经成为治疗肿瘤的主要手段之一。医用加速器技术的不断进步,始终围绕着照射肿瘤的同时最大限度地保护正常器官而发展,但仍无法解决由于高能射线在治疗患者时所带来的辐射污染。高能粒子产生的次级粒子如光子、光中子及质子等对人体组织产生的生物效应同样不可忽略,并逐渐受到重视和广泛的研究。由于加速器机头内部构造的金属元素为铅,靶区主要为钨,光子能量达到>7 Me V时,会超过光核反应阈值从而产生中子,这一反应称为光核反应。国外放疗机构对光中子产生的剂量开展了广泛研究。基于参与复杂相互作用的粒子特点,通过蒙特卡罗模拟和实验测量两个途径来研究医用加速器产生的光中子通量和能谱等物理量。由于医用加速器设计不同(主要是机头内部),性能也有很大差别,因此光中子的通量、能谱和剂量也有不同的分布规律。在文献评阅的基础上,从蒙特卡罗模拟和实验测量两个方面阐述目前对医用加速器产生光中子的研究现状以及放射治疗过程中的辐射防护和引发第二原发癌的物理因素。展开更多
目的:检测非酒精性脂肪肝患者肝组织中糖调节蛋白94的表达情况,探讨非酒精性脂肪肝病(nonalcoholic fattyliver disease,NAFLD)的发病机制.方法:应用半定量逆转录聚合酶链反应(RT-PCR)法和免疫组化法检测脂肪肝组和正常对照组肝组织中...目的:检测非酒精性脂肪肝患者肝组织中糖调节蛋白94的表达情况,探讨非酒精性脂肪肝病(nonalcoholic fattyliver disease,NAFLD)的发病机制.方法:应用半定量逆转录聚合酶链反应(RT-PCR)法和免疫组化法检测脂肪肝组和正常对照组肝组织中糖调节蛋白94基因和蛋白表达,HE染色观察肝脏脂肪变性、炎性活动和坏死,并进行相关分析.结果:非酒精性脂肪肝组脂肪变性、炎症评分及坏死评分较正常对照组明显增加,差异具有统计学意义(3.89±0.32 vs 0.20±0.4;3.67±0.49 vs 0;0.44±0.51 vs 0,P<0.01或0.05).与正常组比较,脂肪肝患者肝组织糖调节蛋白94mRNA和蛋白表达明显增强(0.86±0.02 vs 0.37±0.03;0.34±0.01 vs 0.31±0.01,均P<0.01).糖调节蛋白94mRNA和蛋白表达与脂肪变性、炎症评分及坏死评分明显呈正相关(P<0.01).结论:非酒精脂肪肝引起的肝脏损害可能与糖调节蛋白94表达有关.展开更多
基金financed by the Electric'Drive Laboratory,Department of Electrical Engineering,University of Padova,Padova(haly).
文摘This paper describes the electric drive for an in-wheel fractional-slot axial flux machine,designed for achieving a wide flux-weakening operating region.By using a slotted stator with fractional-slot windings and additional cores enclosing end windings,the axial flux machine reaches a wide constant power speed range.The machine is designed for increasing flux-weakening capability while obtaining low harmonic back-electromotive force and low cogging torque.A 10 N.m axial flux machine exhibiting 3 to 1 flux-weakening speed range has been built.A flux-weakening controller,able to maximize the output torque in the flux-weakening region,is designed and implemented.The goodness of both design and control algorithm is proved by experimental tests.However,such a fractional-slot machine has not only advantages.Rotor losses are very high,and they have to be properly considered during the design process.
基金funded by the National Natural Science Foundation of China(No.51872137)and Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Graphene oxide(GO)as a new nano-enhancer in cement-based materials has gained wide attention.However,GO is easy to aggregate in alkaline cement mortar with poor dispersibility.This hinders its application in practical infrastructure construction.In this work,GO-M18 polycarboxylate compound superplasticizer(GM)were obtained by compounding the M18 polycarboxylate superplasticizer with GO solution at different mass ratios.The dispersion of GM in alkaline solution was systematically studied.The phases and functional groups of GM were characterized by XRD and FTIR.The effects of GM on the cement mortar hydration and the formation of microstructure were investigated by measuring the heat of hydration,MIP,TG/DSC,and SEM.The results show that the long-chain structure of the M18 polycarboxylate superplasticizer can increase the interlayer spacing of GO and weaken the force between GO sheets.The modified GO can be uniformly dispersed in the cement slurry.GM can accelerate the early hydration process of cement,which can increase the content of Ca(OH)2 and decrease the grain size.It can optimize the pore size distribution of cement-based materials,increase the density of harmless and less harmful pores,thereby improving mechanical properties.Such methods can transform traditional cement-based materials into stronger,more durable composites,which prolong the life of cement-based materials and reduce the amount of cement used for later maintenance.This provides an idea for achieving sustainability goals in civil engineering.
文摘随着各种医用加速器新技术的提高和肿瘤患者数量的急剧增加,放射治疗已经成为治疗肿瘤的主要手段之一。医用加速器技术的不断进步,始终围绕着照射肿瘤的同时最大限度地保护正常器官而发展,但仍无法解决由于高能射线在治疗患者时所带来的辐射污染。高能粒子产生的次级粒子如光子、光中子及质子等对人体组织产生的生物效应同样不可忽略,并逐渐受到重视和广泛的研究。由于加速器机头内部构造的金属元素为铅,靶区主要为钨,光子能量达到>7 Me V时,会超过光核反应阈值从而产生中子,这一反应称为光核反应。国外放疗机构对光中子产生的剂量开展了广泛研究。基于参与复杂相互作用的粒子特点,通过蒙特卡罗模拟和实验测量两个途径来研究医用加速器产生的光中子通量和能谱等物理量。由于医用加速器设计不同(主要是机头内部),性能也有很大差别,因此光中子的通量、能谱和剂量也有不同的分布规律。在文献评阅的基础上,从蒙特卡罗模拟和实验测量两个方面阐述目前对医用加速器产生光中子的研究现状以及放射治疗过程中的辐射防护和引发第二原发癌的物理因素。
文摘目的:检测非酒精性脂肪肝患者肝组织中糖调节蛋白94的表达情况,探讨非酒精性脂肪肝病(nonalcoholic fattyliver disease,NAFLD)的发病机制.方法:应用半定量逆转录聚合酶链反应(RT-PCR)法和免疫组化法检测脂肪肝组和正常对照组肝组织中糖调节蛋白94基因和蛋白表达,HE染色观察肝脏脂肪变性、炎性活动和坏死,并进行相关分析.结果:非酒精性脂肪肝组脂肪变性、炎症评分及坏死评分较正常对照组明显增加,差异具有统计学意义(3.89±0.32 vs 0.20±0.4;3.67±0.49 vs 0;0.44±0.51 vs 0,P<0.01或0.05).与正常组比较,脂肪肝患者肝组织糖调节蛋白94mRNA和蛋白表达明显增强(0.86±0.02 vs 0.37±0.03;0.34±0.01 vs 0.31±0.01,均P<0.01).糖调节蛋白94mRNA和蛋白表达与脂肪变性、炎症评分及坏死评分明显呈正相关(P<0.01).结论:非酒精脂肪肝引起的肝脏损害可能与糖调节蛋白94表达有关.
