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Effect of extrusion temperature on microstructure and mechanical properties of a low-alloying and ultra-high strength Mg-Zn-Ca-Mn matrix composite containing trace TiC nanoparticles

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j.urnal of Magnesium and Alloys 2020年第3期8卷 676-691页

作者： K.B.nie Z.H.Zhu K.K.deng j.G.Han College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024PR China Sharvci key laboratory of advanced magnesium-based materials Taiyuan University of TechnologyTaiyuan 030024PR China

Mechanical properties of microalloying Mg-2.2Zn-1.8Ca-0.5Mn(wt%)matrix composites reinforced by 0.5 wt%TiC nanoparticles before and after extrusion were investigated based on the detailed microstructural analysis.A uniform distribution of TiC nanoparticles was realized in the nanocomposite by the method of ultrasonic-assisted semisolid *** morphology of eutectic Ca2Mg6Zn3 phases changed from plate-like in the free TiC nanoparticles region to lamellar in the dense TiC nanoparticles region for the as-cast *** the grain structure and precipitates were obviously refined as the extrusion temperature decreased from 350 to 270℃.The nanocomposite exhibited excellent tensile yield strength(352-428 MPa)which was governed by the extrusion *** grain refinement strengthening with the contribution ratio of^80%to this strength increment was much higher relative to thermal expansion effect,Orowan strengthening and dislocation *** recrystallized grain structure with a substantial of ne precipitates appeared in the nanocomposite extruded at 270℃.The refined grain structure was not only due to dynamic recrystallization,but also the synergistic pinning effect of nano-TiCp,precipitated MgZn2 and α-Mn *** tensile toughness value of nanocomposite after extrusion improved with increasing the extrusion *** micro-cracks formed along the remnant coarse Ca2Mg6Zn3 led to the structural failure during tension.

关键词： Magnesium matrix nanocomposite Microstructure Mechanical properties:Strengthening mechanism Extrusion

Reproductive potential of field-collected overwintering boll weevils （Coleoptera： Curculionidae） fed on pollen in the laboratory

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Insect Science 2009年第4期16卷 321-327页

作者： S. M. Greenberg G. d. j.nes j. j. Adamczyk, j.. F. Eischen j. S. Armstrong R. j. Coleman M. Setamou Tong-Xian Liu USdA-ARS-KSARC-BIRU 2413 E. Hwy. 83 Weslaco Texas 78596 APMRU-SPA-ARS-USdA College Station Texas 77845 USdA- ARS-KSA RC-Honey Bee Research Unit Texas A&M University Kingsville Citrus Center Weslaco TX 78596 department of Entomology Texas AgriLife Research Texas A&M University System Weslaco Texas 78596 USA

The reproductive potential of overwintering boll weevil, Anthonomus grandis grandis （Boheman）, females collected from pheromone traps in September, November and j.nuary, fed for 1, 3, and 5 weeks on plant pollens, and then provided cotton squares, was determined in the laboratory at 27 ~ I^C, 65% RH, and a photoperiod 13 ： 11 （L ： d） h. duration of pollen feeding by overwintering boll weevils did not significantly influence egg and feeding punctures, or puncture ratios （egg to total punctures） for any of the three months of parent weevil collections when provided cotton squares on a daily basis. However, punctures and puncture ratios are significantly different when comparing mean data between months of boll weevil collections. When boll weevils were provided with cotton squares daily, the pre-ovipositional periods of female parents captured in September, November and j.nuary were 5, 9 and 14 days, respectively. The rate of eggs by females was significantly lower during November and j.nuary than September. Female parents collected in September produced a significantly higher percentage of eggs yielding adult progeny than those collected in November and j.nuary. Life table parameters indicated that net reproductive rate （Ro） of boll weevil females collected in September was 1.2- fold higher than those collected in November and 10.7-fold higher than those collected in j.nuary. Except for testes size, no differences in male reproductive parameters were observed during the cotton-free period compared with males captured during mid-cotton （j.ne）. The number of oocytes in the ovarioles and the number of ooeytes containing yolk were significantly lower during September, November and j.nuary compared with j.ne. The reproductive potential ofoverwintering boll weevil females collected in different months is an important consideration in determining the success of any control strategy.

关键词： Anthonomusgrandisgrandis overwintering boll weevil reproductive pollen

基于自适应滑模控制器的PMSM调速策略研究

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郑州大学学报（理学版） 2025年第1期57卷 88-94页

作者：王要强王秋旭聂福全张晓光梁军郑州大学电气与信息工程学院河南郑州450001 河南省电力电子与电力系统工程技术研究中心河南郑州450001 河南科技学院机电学院河南新乡453400 北方工业大学电气与控制工程学院北京100144 卡迪夫大学工程学院英国卡迪夫CF243AA

为了提高永磁同步电机的调速性能,滑模控制逐渐取代PI控制被引入控制系统中。但是传统滑模控制中趋近律的趋近速度慢与固有抖振问题制约着滑模控制的发展,为此提出一种改进的滑模趋近律。首先,为了解决传统等速趋近律中趋近速度和抖振... 详细信息

为了提高永磁同步电机的调速性能,滑模控制逐渐取代PI控制被引入控制系统中。但是传统滑模控制中趋近律的趋近速度慢与固有抖振问题制约着滑模控制的发展,为此提出一种改进的滑模趋近律。首先,为了解决传统等速趋近律中趋近速度和抖振难以平衡的问题,在所提趋近律中引入系统状态变量,并在滑模增益中引入指数项,使其在保证趋近速度的同时抑制滑模抖振。其次,由于开关函数在零点附近具有不连续的特性,会引起滑模抖振,为此采用sat函数代替常规开关函数,能够在保证响应速度的前提下抑制滑模抖振。然后,基于所提趋近律,设计永磁同步电机的滑模速度控制器。最后,仿真和实验结果表明,所提趋近律可以提高永磁同步电机调速系统的控制性能。

关键词：永磁同步电机滑模控制自适应趋近律 sat函数系统状态量

How to do when PFO closure failed under routine guidance:the first clinical experience for PFO closure

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j.urnal of Geriatric Cardiology 2021年第1期18卷 89-90页

作者： Ying ZHOU j.n-Gang nie department of Pharmacy the First Affiliated Hospital of Nanchang UniversityNanchangChina department of Cardiology the First Affiliated Hospital of Nanchang UniversityNo.17 YongwaizhengjieDonghu DistrictNanchangChina

Patent foramen ovale(PFO)is the most common abnormality of fetal origin and is affecting approximately 25%of the worldwide adult population.[1]during the past two decades,instead of surgical closure,catheter-based procedures to close the PFO have become widely used among *** guidance with fluoroscopy,transesophageal echocardiography(TEE)or intracardiac echocardiography have been the mainstream technique to ensure a safe and successful procedure.

关键词： PFO routine closure

Magnesium matrix composite reinforced by nanoparticles-A review

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j.urnal of Magnesium and Alloys 2021年第1期9卷 57-77页

作者： K.B.nie X.j.Wang K.K.deng X.S.Hu K.Wu State Key Laboratory of Advanced Welding and j.ining Harbin Institute of TechnologyHarbin 150001China College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China

Significant progress has been made in magnesium-based composites during recent decades,especially for the appearance of magnesium matrix composite reinforced by *** nanoparticles added not only exhibit a good strengthening effect,but also maintain the initial toughness of the matrix,effectively balancing the contradiction between the strength and plasticity in the traditional magnesium matrix *** magnesium matrix nanocomposites with excellent mechanical properties have pushed the development of magnesium matrix composites to a new ***,it is very difficult to disperse the nanoparticles in metal melt especially in magnesium melt which is different from other metal melts and dangerous during the cast *** means that the preparation of magnesium matrix nanocomposite is extremely ***,the magnesium matrix nanocomposites possess a distinctive characteristic in deformation behavior,strengthening and toughening mechanism due to their special size effect of ***,this review will focus on the new preparation technologies,deformation behavior,mechanical properties and strengthening and toughening *** potential applications,development trends and future research ideas of magnesium matrix nanocomposite are also prospected.©2020 Published by Elsevier *** behalf of Chongqing University.

关键词： Magnesium matrix nanocomposite Microstructure Mechanical properties Strengthening mechanism

Seed-assisted growth for high-performance perovskite solar cells:A review

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j.urnal of Energy Chemistry 2024年第9期96卷 588-610页

作者： Zhimin Fang Ting nie j.anning ding Shengzhong(Frank)Liu Institute of Technology for Carbon Neutralization Yangzhou UniversityYangzhou 225127JiangsuChina dalian National Laboratory for Clean Energy iChEMDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina Key Laboratory of Applied Surface and Colloid Chemistry Ministry of EducationShaanxi Key Laboratory for Advanced Energy DevicesShaanxi Engineering Lab for Advanced Energy TechnologySchool of Materials Science and EngineeringShaanxi Normal UniversityXi’an 710119ShaanxiChina

The rapid increase in the power conversion efficiency(PCE)of perovskite solar cells(PSCs)is closely related to the development of deposition techinique for perovskite *** high-quality perovskite film enables efficient charge transportation and less trap states,which are eventually translated into enhanced device ***-assisted growth(SAG)is a potential technique for depositing highly-crystallized perovskite films with preferential crystal orientation among the numerous approaches related to crystallization *** this review,we summarize the recent advances in the SAG technique for both one-step and two-step processed perovskite ***,seeding at the buried interface and on the top surface are also *** present different seeds and their corresponding seeding mechanism in detail,such as inorganic nanomaterials,organic ammoniums,alkali metal halides,and perovskite ***,challenges and perspectives are proposed to investigate the potential expansion of seeding engineering in high-performance PSCs,particularly large-area devices.

关键词： Perovskite solar cell Seed Crystallization Efficiency

Superplastic behavior of a powder metallurgy superalloy during isothermal compression

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j.urnal of Materials Science & Technology 2019年第11期35卷 2591-2599页

作者： Liming Tan Yunping Li Feng Liu Yan nie Liangj.ang State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Powder Metallurgy Research Institute Central South UniversityChangsha 410083China High Temperature Materials Research Institute Central South UniversityChangsha 410083China Yuanmeng Precision Technology(Shenzhen)Institute Shenzhen 518000China

In this work,the flow behaviors and microstructure evolution of a powder metallurgy nickel-based superalloy during superplastic compression is *** on the strain rate sensitivity m determined by flow data,superplastic region is estimated at relatively low temperature and strain rate domains,specifically around 1000℃/10^-3s^-***,the cylinder specimens are isothermally compressed at 1000℃/10^-3s^-1 and 1025℃/10^-3s^-1 with different strains,to exam the superplasticity and related *** experimental results indicate that the accumulated dislocations are mainly annihilated by dynamic recovery and dynamic recrystallization(dRX),and the grain boundary sliding(GBS)contributes to the total strain during superplastic compression as *** addition,the cavities and cracks at triple j.nctions or interfaces between matrix and second phase particle have not been detected,which is different from superplastic tensile deformation.

关键词： Nickel-based superalloy Superplastic deformation dynamic recrystallization Grain boundary sliding Hot compression

A SIMPLE PRECONdITIONEd dOMAIN dECOMPOSITION METHOd FOR ELECTROMAGNETIC SCATTERING PROBLEMS

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j.urnal of Computational Mathematics 2013年第1期31卷 1-21页

作者： F. Alouges j. Bo-urguignon-Mirebeau - I d.P. Levadoux CMAP Ecole Polytechnique Palaiseau France Laboratoire de Mathdmatiques Universitd Paris-Sud XI Orsay France dEMR-SFM ONERA Palaiseau France

We present a domain decomposition method （ddM） devoted to the iterative solution of time-harmonic electromagnetic scattering problems, involving large and resonant cavities. This ddM uses the electric field integral equation （EFIE） for the solution of Maxwell problems in both interior and exterior subdomains, and we propose a simple preconditioner for the global method, based on the single layer operator restricted to the fictitious interface between the two subdomains.

关键词： Electromagnetism integral equations methods domain decomposition meth-ods Preconditioning Cavities.

Combinatorial therapies for spinal cord inj.ry: strategies to induce regeneration

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Neural Regeneration Research 2019年第1期14卷 69-71页

作者： Eduardo d.Gomes Nuno A.Silva António j. Salgado Life and Health Sciences Research Institute (ICVS) School of Medicine University of Minho Campus de Gualtar ICVS/3B’s–PT Government Associate Laboratory

Spinal cord inj.ry(SCI)is a condition without treatment,mainly characterized by the loss of motor and sensory function below the level of *** is accompanied by several complications such as cardiac and respiratory compromise,and often patients present psychological ailments associated with the drastic alteration of their normal *** pathophysiology derives from a massive damage to the spinal cord tissue,which is propagated

关键词：损害绳索新生治疗感觉功能生活方式星形细胞并发症