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轧钢 1989年第2期6卷 10-15页

作者： H.Feldmann g.engel W.Ellinghaus 钱健清 SMSSchloemann-Siemag公司

在过去五十年中制造的许多大型型钢轧机采用传统的轧机形式,即1架辊身长度不超过2700mm的粗轧机;3～5架横列式布置的二辊成型轧机。传统的用于生产工字钢、槽钢、钢轨、钢板桩、角钢、方钢等的轧机机组,生产能力约为40×14~4t,其布置如... 详细信息

在过去五十年中制造的许多大型型钢轧机采用传统的轧机形式,即1架辊身长度不超过2700mm的粗轧机;3～5架横列式布置的二辊成型轧机。传统的用于生产工字钢、槽钢、钢轨、钢板桩、角钢、方钢等的轧机机组,生产能力约为40×14~4t,其布置如图1所示。

关键词：型钢轧机型材轧制轨梁轧制

使用磁敏感加权成像评估脊髓神经根病变中颈椎椎间孔狭窄情况

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国际医学放射学杂志 2019年第3期 375-376页

作者：田恬 g.engel Y.Y.Bender L.C.Adams S.M.Boker U.L.Fahlenkamp M.Wagner Department of Radiology Charité-University Medicine Berlin

摘要目的以CT结果为参考标准,评价磁敏感加权MRI(SW-MRI)对颈椎椎间孔狭窄(FS)的诊断效果,并与常规MRI序列影像进行比较。材料与方法前瞻性纳入21例

关键词：椎间孔狭窄 SW 神经根病敏感度特异度

Cretaceous crown male ant reveals the rise of modern lineages

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Zoological Research 2024年第5期45卷 983-989页

作者： Qiong Wu Alexander g.Radchenko Michael S.engel Xiao-Qin Li Hong-Ru Yang Xing-Ru Li Chung-Kun Shih Dong Ren Tai-Ping gao College of Life Sciences Capital Normal UniversityBeijing 100048China I.I.Schmalhausen Institute of Zoology NAS of UkraineKiev 01054Ukraine Division of Invertebrate Zoology American Museum of Natural HistoryNew York 10024-5192USA Facultad de Ciencias Biológicas Universidad Nacional Mayor de San MarcosLima 11-0058Perú Departamento de Entomología Museo de Historia NaturalUniversidad Nacional Mayor de San MarcosLima 15072Perú Department of Chemistry Analytical and Testing CenterCapital Normal UniversityBeijing 100048China Department of Paleobiology National Museum of Natural HistorySmithsonian InstitutionWashington DC 20013-7012USA

Most described Mesozoic ants belong to stem groups that existed only during the Cretaceous ***,the earliest known crown ants were dated to the Turonian(Late Cretaceous,ca.94-90 million years ago(Ma))deposits found in the USA,Kazakhstan,and ***,the recent discovery of an alate male ant in Kachin amber from the earliest Cenomanian(ca.99 Ma),representing a new genus and species,Antiquiformica alata,revises the narrative on ant *** can be distinctly differentiated from all known male stem ants by its geniculate antennae with elongated scape,extending far beyond the occipital margin of the head and half the length of the funiculus,as well as its partly reduced forewing ***,the combination of a one-segmented waist with a well-developed node,elongated scape extending beyond the occipital margin,and reduced forewing venation,particularly the completely reduced m-cu and rs-m crossveins and absence of rm and mcu closed cells,firmly places the fossil within the extant subfamily *** transform infrared spectroscopy(FTIR)confirmed that the amber containing Antiquiformica alata originated from the Kachin mines in *** discovery significantly revises our understanding of the early evolution of *** presence of Antiquiformica in Cenomanian amber indicates that the subfamily Formicinae emerged at least by the start of the Late Cretaceous,with crown ants likely originating earlier during the earliest Cretaceous or possibly the Late Jurassic,although paleontological evidence is lacking to support the latter hypothesis.

关键词： Formicidae Formicinae Morphology Taxonomy Antiquiformica alata Paleontology Kachin amber

Comparative analysis of 12 water lily plastid genomes reveals genomic divergence and evolutionary relationships in early flowering plants

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Marine Life Science & Technology 2024年第3期6卷 425-441页

作者： Weicai Song Wenbo Shi Huan Wang Zirui Zhang Ruiqing Tao Jin Liu Shuo Wang Michael S.engel Chao Shi College of Marine Science and Biological Engineering Qingdao University of Science and TechnologyQingdao 266042China Plant germplasm and genomics Center Germplasm Bank of Wild Species in Southwest ChinaKunming Institute of BotanyThe Chinese Academy of SciencesKunming 650204China Yunnan Institute of Tropical Crops Xishuangbanna 666100China American Museum of Natural History New YorkNY 10024-5192USA Natural History Museum and Department of Ecology&Evolutionary BiologyUniversity of KansasLawrenceKS 66045USA

The aquatic plant Nymphaea,a model genus of the early flowering plant lineage Nymphaeales and family Nymphaeaceae,has been extensively ***,the availability of chloroplast genome data for this genus is incomplete,and phylogenetic relationships within the order Nymphaeales remain *** this study,12 chloroplast genomes of Nymphaea were assembled and analyzed for the first *** genomes were 158,290-160,042 bp in size and contained 113 non-repeat genes,including 79 protein-coding genes,30 tRNA genes,and four rRNA *** also report on codon usage,RNA editing sites,microsatellite structures,and new repetitive sequences in this *** genomics revealed that expansion and contraction of IR regions can lead to changes in the gene ***,it was observed that the highly variable regions of the chloroplast genome were mainly located in intergenic ***,the phylogenetic tree showed the order Nymphaeales was divided into three families,and the genus Nymphaea can be divided into five(or three)subgenera,with the subgenus Nymphaea being the *** divergence times of nymphaealean taxa were analyzed,with origins of the order Nymphaeales and family Nymphaeaceae being about 194 and 131 million years,*** results of the phylo-genetic analysis and estimated divergence times will be useful for future evolutionary studies of basal angiosperm lineages.

关键词： Aquatic plants Nymphaea Phylogenetic analysis Plastid genomics Structural variation

Challenges and opportunities in the production of magnesium parts by directed energy deposition processes

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Journal of Magnesium and Alloys 2024年第5期12卷 1663-1686页

作者： gürel Cam Ali günen Iskenderun Technical University Faculty of Engineering and Natural SciencesDepartment of Mechanical Engineering31200 Iskenderun-HatayTurkey Iskenderun Technical University Faculty of Engineering and Natural SciencesDepartment of Metallurgy and Materials Engineering31200 Iskenderun-HatayTurkey

Mg-alloys have gained considerable attention in recent years for their outstanding properties such as lightweight,high specific strength,and corrosion resistance,making them attractive for applications in medical,aerospace,automotive,and other transport ***,their widespread application is hindered by their low formability at room temperature due to limited slip *** Mg-alloys have low mechanical properties due to the presence of casting defects such as porosity and anisotropy in addition to the high *** casting methods benefit from established process optimization techniques for these problems,additive manufacturing methods are increasingly replacing casting methods in Mg alloys as they provide more precise control over the microstructure and allow specific grain orientations,potentially enabling easier optimization of anisotropy properties in certain *** metal additive manufacturing(MAM)technology also results in some manufacturing defects such as inhomogeneous microstructural evolution and porosity and additively manufactured Mg alloy parts exhibit lower properties than the wrought parts,they in general exhibit superior properties than the cast ***,MAM is a promising technique to produce Mg alloy *** energy deposition processes,particularly wire arc directed energy deposition(WA-DED),have emerged as an advantageous additive manufacturing(AM)technique for metallic materials including magnesium alloys,offering advantages such as high deposition rates,improved material efficiency,and reduced production costs compared to subtractive ***,the inherent challenges associated with magnesium,such as its high reactivity and susceptibility to oxidation,pose unique hurdles in the application of this *** review paper delves into the progress made in the application of DED technology to Mg-alloys,its challenges,and ***,the predominant imperfections,notably inhomo

关键词： Additive manufacturing DED processes Arc-DED Wire arc additive manufacturing(WAAM) 3-D printing High deposition rate

Recent research in mechanical properties of geopolymer-based ultrahigh-performance concrete:A review

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Defence Technology（防务技术） 2024年第2期32卷 67-88页

作者： g.Murali Division of Research&Innovation Uttaranchal UniversityDehradun 248007India

Due to the growing need for sustainable and ultra-high-strength construction materials,scientists have created an innovative ultra-high-performance concrete called geopolymer based ultra-highperformance concrete(gUHPC).Besides,in the last few decades,there have been a lot of explosions and ballistic attacks around the world,which have killed many civilians and fighters in border *** this context,this article reviews the fresh state and mechanical properties of ***,the ingredients of gUHPC and fresh properties such as setting time and flowability are briefly ***,the review of compressive strength,flexure strength,tensile strength and modulus of elasticity of fibrous ***,the blast and projectile impact resistance performance was ***,the microstructural characteristics were reviewed using the scanning electron microscope and X-ray Powder *** review outcome reveals that the mechanical properties were increased when 30%silica fume was added to a higher dose of steel fibre to improve the microstructure of *** is hypothesized that the brittleness of gUHPC was mitigated by adding 1.5%steel fibre reinforcement,which played a role in the decrease of contact explosion cratering and *** the need for cement in gUHPC was a key factor in the review,indicating a promising potential for lowering carbon ***,gUHPC research is still in its early stages,so more study is required before its full potential can be utilized.

关键词： Mechanical properties Blast Projectile impact Fibre geopolymer Silica fume Alkaline activators

Shell-model representations of the microscopic version of the Bohr-Mottelson collective model

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Communications in Theoretical Physics 2024年第8期76卷 79-90页

作者： H g ganev Joint Institute for Nuclear Research DubnaRussia Institute of Mechanics Bulgarian Academy of SciencesSofiaBulgaria

The structure of the irreducible collective spaces of the group Sp(12,R),which many-particle nuclear states are classified according to the chain Sp(12,R)⊃U(6)⊃SO(6)⊃SU_(pn)(3)⊗SO(2)⊃SO(3)of the proton-neutron symplectic model(PNSM),is considered in *** chain of the PNSM was recently shown to correspond to a microscopic shell-model version of the Bohr-Mottelson collective *** construction of the relevant shell-model representations of the Sp(12,R)group along this chain is considered for three nuclei with varying collective properties and from different mass *** is shown that the SU_(pn)(3)basis states of the Sp(12,R)representations belonging to the SO(6)irreps with seniorityυ≥υ0,withυ0 denoting the maximal seniority SO(6)irrep contained in the Sp(12,R)bandhead,are always Pauli allowed,but organized in a different way into different SO(6)*** is in contrast to the case of filling the levels of the standard three-dimensional harmonic oscillator and using the plethysm *** the SU_(pn)(3)multiplets withinυ<υ0 are not all Pauli forbidden,it is safe to discard *** results obtained in the present work are important for the practical application of the microscopic version of the Bohr-Mottelson collective model.

关键词： microscopic shell-model version of the Bohr-Mottelson model proton-neutron symplectic model Sp(12,R)dynamical algebra shell-model representations

Harmonics in the Squirrel Cage Induction Motor Analytic Calculation Part III: Influence on the Torque-speed Characteristic

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CES Transactions on Electrical Machines and Systems 2024年第1期8卷 86-102页

作者： g.Kovács the ganz Electric Works BudapestHungary

The harmonics that appear in the squirrel cage asynchronous machine have been discussed in great detail in the literature for a long time. However, the systematization of the phenomenon is still pending, so we made an attempt to fill this gap in the previous parts of our study by elaborating formulas for calculation of parasitic torques. It was a general demand among those who work in this field towards the author to verify his formulas with measurements. In the literature, it seems,only one detailed, purposeful series of measurements has been published so far, the purpose of which was to investigate the effect of the number of rotor slots on the torque-speed characteristic curve of the machine. The main goal of this study is to verify the correctness of the formulas by comparing them with the referred series of measurements. Relying on this, the expected synchronous parasitic torques were developed for the frequently used rotor slot numbers-as a design guide for the ***, together with our complete table for radial magnetic pull published in our previous work, the designer has all the principles, data and formulas available for the right number of rotor slots for his given machine and for the drive system. This brings this series of papers to an end.

关键词： Asynchronous parasitic torques Induction motor Squirrel cage rotor Space harmonics Synchronous parasitic torques

Neuroimaging in atypical normal tension glaucoma:debating routine implementation in the absence of classic neurological findings

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International Journal of Ophthalmology(English edition) 2024年第3期17卷 509-517页

作者： Umay güvenç gülizar Demirok güner Üney Selma Uzman Ophthalmology Department Ankara Training and Research HospitalAnkara 06230Turkey

●AIM:To assess the necessity of neuroimaging in patients with neurological or atypical findings of normal tension glaucoma(NTg)who do not exhibit typical glaucoma manifestations.●METHODS:A retrospective analysis was conducted on 90 atypical NTg patients who underwent cranial magnetic resonance imaging(MRI)due to atypical *** demographic characteristics,clinical parameters,and radiological findings were recorded.●RESULTS:Among the patients,66.7%had abnormal radiology results,with the most common findings being gliosis(34.4%),sequelae of cerebrovascular events and vascular malformations(14.4%),and benign intracranial mass lesions(11%).Non-glaucomatous visual field defects were more frequently observed in patients with abnormal neuroimaging ***,there were no significant differences in intraocular pressure,optic disc parameters,retinal nerve fiber layer thickness,and visual field indices between patients with normal and abnormal radiological *** mean age of the patients was ***,there was a significant age difference,with the abnormal radiology group having a higher median age(P=0.021).●CONCLUSION:The study highlights the importance of cranial imaging in older NTg patients to detect underlying pathologies and prevent *** suggests that neuroimaging may be warranted in NTg patients with atypical visual field defects incompatible with ***,routine neuroimaging in all NTg patients without classic neurological signs may not be necessary.

关键词： normal tension glaucoma neuroimaging atypical visual field defects