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Acta Mechanica Sinica 2016年第4期32卷 720-730页

作者： W.Yuan l.li D.G.Zhang J.Z.Hong School of Science Nanjing University of Science and Technology Department of Engineering Mechanics Shanghai Jiao Tong University

A flexible beam with large overall rotating motion impacting with a rigid slope is studied in this paper. The tangential friction force caused by the oblique impact is analyzed. The tangential motion of the system is divided into a stick state and a slip state. The contact constraint model and Coulomb friction model are used respectively to deal with the two states. Based on this hybrid modeling method, dynamic equations of the system, which include all states（before, during, and after the collision）are obtained. Simulation results of a concrete example are compared with the results obtained from two other models： a nontangential friction model and a modified Coulomb model. Differences in the results from the three models are discussed. The tangential friction force cannot be ignored when an oblique impact occurs. In addition, the results obtained from the model proposed in this paper are more consistent with real movement.

关键词： collision oblique friction stick tangential considering Coulomb constraint coordinate rotating

In-situ synchrotron high energy X-ray diffraction study on the internal strain evolution of D019-α2 phase during high-temperature compression and subsequent annealing in a TiAl alloy

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Journal of Materials Science & Technology 2023年第32期163卷 212-222页

作者： X.liu l.Song A.Stark F.Pyczak T.B.Zhang State Key laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Innovation Center NPU Chongqing Northwestern Polytechnical UniversityChongqing 400000China Institute of Materials Physics Helmholtz-Zentrum HereonMax Planck-Str.1Geesthacht 21502Germany

The residual stress in the D019-α2 phase is known to be significantly higher than that in the l10-γphase in TiAl alloys after deformation due to the poor plasticity and strong mechanical anisotropy of theα2 ***,the internal stress accumulation and relaxation in theα2 phase during high-temperature deformation and annealing are scarcely *** this study,for the first time,the internal strain evolution and load partitioning between theα2 andγphases at high temperatures are characterized by in-situ synchrotron high energy X-ray diffraction(HEXRD)*** plastic deformation is at least initiated at a stress of roughly 200 MPa in theγphase and 775 MPa in theα2 *** intergranular strains in theα2 phase are generated by the onset of dislocation glide in theγphase,and accentuated with the accumulated dislocations and the ensuing twinning *** unloading,great intergranular strains are preserved in theα2 phase constrained by the heavily plastically deformedγ*** subsequent heating from 400 to 1000℃,the internal strains in theα2 phase are almost fully relaxed by substantial dislocation annihilation and rearrangement in theγ*** annealing at 800℃,the internal strain relaxation is rapid in the initial 10 min,whereas considerably retarded *** extent of relaxation after holding at 800℃for 1 h is equivalent to that of heating in an effective temperature range of 680-880℃for 10 *** in-situ lattice strain measurements with various thermal relaxation schemes provide guidance for the stress relief annealing of TiAl components.

关键词： TiAl alloys Synchrotron radiation Intergranular strain Stress relaxation

Two-Factor Cancelable Biometrics Authenticator

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Journal of Computer Science & Technology 2007年第1期22卷 54-59页

作者：彭颖涵 Andrew T. B. J David N. C. l Faculty of Information Science and Technology Multimedia University dalan Ayev Keroh Lama 75450 Melaka Malaysia

Biometrics-based authentication system offers advantages of providing high reliability and accuracy. However the contemporary authentication system is impuissance to compromise. If a biometrics data is compromised, it cannot be replaced and rendered unusable. In this paper, a cancelable biometrics-based authenticator is proposed to solve this irrevocability issue. The proposed approach is a two-factor authentication system, which requires both of the random data and facial feature in order to access the system. In this system, tokenized pseudo-random data is coupled with momentbased facial feature via inner product algorithm. The output of the product is then discretized to generate a set of private binary code, coined as 2factor-Hashing code, which is acted as verification key. If this biometrics-based verification key is compromised, a new one can be issued by replacing a different set of random number via token replacement. Then, the compromised one is rendered completely useless. This feature offers an extra protection layer against biometrics fabrication since the verification code is replaceable. Experimental results demonstrate that the proposed system provides zero Equal Error Rate in which there is a clear separation in between the genuine and the imposter distribution populations.

关键词： cancelable biometrics face recognition Geometric moments,pseudo Zernike moment

Recovery of alkali and alumina from Bayer red mud by the calcification–carbonation method

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International Journal of Minerals,Metallurgy and Materials 2016年第3期23卷 257-268页

作者： xiao-feng zhu ting-an zhang yan-xiu wang guo-zhi lü wei-guang zhang Key laboratory of Ecological Utilization of Multi-metal Intergrown Ores of the Ministry of Education School of Materials and MetallurgyNortheastern UniversityShenyang 110819China

Red mud produced in the Bayer process is a hazardous solid waste because of its high alkalinity; however, it is rich in valuable components such as titanium, iron, and aluminum. In this study, a novel calcification-carbonation method was developed to recover alkali and alumina from Bayer red mud under mild reaction conditions. Batch experiments were performed to evaluate the potential effects of im- portant parameters such as temperature, amount of CaO added, and CO2 partial pressure on the recovery of alkali and alumina. The results showed that 95.2% alkali and 75.0% alumina were recovered from red mud with decreases in the mass ratios of Na2O to Fe2O3 and of Al2O3 to Fe2O3 from 0.42 and 0.89 to 0.02 and 0.22, respectively. The processed red mud with less than 0.5wt% Na2O can potentially be used as a construction material.

关键词： waste utilization red mud calcification carbonation alumina alkali recovery

Toward implantable devices for angle-sensitive,lens-less,multifluorescent,single-photon lifetime imaging in the brain using Fabry-Perot and absorptive color filters

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light(Science & Applications) 2022年第2期11卷 197-211页

作者： Adriaan J.Taal Changhyuk lee Jaebin Choi Björn Hellenkamp Kenneth l.Shepard Columbia University-Department of Electrical Engineering 500W.120th St.Mudd 1310New York 10027 NYUSA Korea Institute of Science and Technology-Brain Science Institute 5 Hwarang-ro 14-gilSeongbuk-guSeoul 02792Republic of Korea

Implantable image sensors have the potential to revolutionize *** to their small form factor requirements;however,conventional filters and optics cannot be *** limitations obstruct highresolution imaging of large neural *** advances in angle-sensitive image sensors and single-photon avalanche diodes have provided a path toward ultrathin lens-less fluorescence imaging,enabling plenoptic sensing by extending sensing capabilities to include photon arrival time and incident angle,thereby providing the opportunity for separability of fluorescence point sources within the context of light-field microscopy(lFM).However,the addition of spectral sensitivity to angle-sensitive lFM reduces imager resolution because each wavelength requires a separate pixel ***,we present a 1024-pixel,50μm thick implantable shank-based neural imager with color-filtergrating-based angle-sensitive *** angular-spectral sensitive front end combines a metal–insulator–metal(MIM)Fabry–Perot color filter and diffractive optics to produce the measurement of orthogonal light-field information from two distinct colors within a single *** result is the ability to add independent color sensing to lFM while doubling the effective pixel *** implantable imager combines angular-spectral and temporal information to demix and localize multispectral fluorescent *** this initial prototype,this is demonstrated with 45μm diameter fluorescently labeled beads in scattering *** lifetime imaging is exploited to further aid source separation,in addition to detecting pH through lifetime changes in fluorescent *** these initial fluorescent targets are considerably brighter than fluorescently labeled neurons,further improvements will allow the application of these techniques to in-vivo multifluorescent structural and functional neural imaging.

关键词： filters lifetime angle

Combined immunohistochemical and retrograde tracing reveals little evidence of innervation of the rat dentate gyrus by midbrain dopamine neurons

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Frontiers in Biology 2016年第3期11卷 246-255页

作者： Charlotte M. Ermine Jordan l. Wright Clare l. Parish Davor Stanic lachlan H. Thompson The Florey Institute for Neuroscience and Mental Health The University of Melbourne Parkville Victoria 3010 Australia Current address Wolfson Institute for Biomedical Research University College London Gower Street London WC1E 6BT UK

Although the functional neuroanatomy of the midbrain dopamine （mDA） system has been well characterized, the literature regarding its capacity to innervate the hippocampal formation has been inconsistent. The lack of expression of definitive markers for dopaminergic fibers, such as the dopamine transporter, in the hippocampus has complicated studies in this area. Here we have used immunohistochemical techniques to characterize the tyrosine hydroxylase expressing fiber network in the rat hippocampus, combined with retrograde tracing from the dentate gyrus to assess the capacity for afferent innervation by mDA neurons. The results indicate that virtually all tyrosine hydroxylase fibers throughout the hippocampus are of a noradrenergic phenotype, while the overlying cortex contains both dopaminergic and noradrenergic fiber networks. Furthermore, retrograde tracing from the dentate gyrus robustly labels tyrosine hydroxylase-immunoreactive noradrenergic neurons in the locus coeruleus but not mDA neurons.

关键词： noradrenaline hippocampus connectivity DAT neurogenesis

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Pedosphere 2017年第4期27卷 747-757页

作者： Alba l.A.SKORUPA Sérgio H.G.SIlVA Giovana C.POGGERE Diego TASSINARI leundro C.PINTO Yuri l.ZINN Nilton CURI Departamento de Ciéncia do Solo Universidade Federal de LavrasCampusLavras MG 37200-000Brazil

Soils result from the interaction of five independent formation *** one factor varies,while the others remain constant,different soils can be ***,we demonstrated an opposing trend,wherein two soils were similar,despite considerable differences in all factors of soil *** sampled two Inceptisols(Oxic Dystrudepts) formed on different parent materials(gneiss *** schist),climate(tropical altimontane ***,drier plateau),topography(1 650 m,45% slope vs.1 000 m,8% slope),time(rejuvenated ***,stable surface),and vegetation(rainforest *** savanna).The two soils had similar chemical properties,whereas the soil on mica schist had finer particle size distribution,lower porosity,and lower saturated hydraulic *** properties were related to a coarser blocky microstructure compared to the soil on *** soils presented active mineral weathering and pronounced pedoplasmation,demonstrated by clay contents>300 g kg^(-1),although only the Dystrudept on gneiss possessed coarse rock *** C horizons of both soils presented fragmented clay coatings suggestive of argilluviation,likely relict,because they were not observed in the B *** similarities in many properties of the two Dystrudepts,despite contrasting factors of soil formation,suggest converging evolution and that soil classification at the subgroup level was efficient in grouping similar formative processes in tropical ***,this work revealed that similar pedogenic processes acting on different factors of soil formation can result in similar soil properties,at least for Inceptisols where further soil development is hindered by topographic limitations.

关键词： mineral weathering, Oxic Dystrudept, pedogenic process, soil genesis, soil micromorphology, soil property, soil taxonomy

Non-aerated liquid culture promotes shoot organogenesis in Eucalyptus globulus labill

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Journal of Forestry Research 2018年第3期29卷 621-627页

作者： T.D.Salla C.dos S.Silva K.l.de G.Machado l.V.Astarita E.R.Santarém laboratory of Plant Biotechnology Faculdade de Biociências Pontifícia Universidade Católica do Rio Grande do Sul

Eucalyptus is very recalcitrant to in vitro *** this research, an efficient shoot organogenesis system was developed using 60-day-old plants of Eucalyptus globulus grown in vitro and non-aerated liquid medium to improve shoot proliferation. Cultures were initiated with hypocotyls and leaf segments from plantlets cultivated on semisolid 1/2 MS modified medium supplemented with 4.44 μM 6-Benzyladenine(BA) and 16.1 μM 1-Naphthaleneacetic acid(NAA). Calli were transferred to shoot induction medium, with either 0.5 or 2.7 μM NAA. Shoot multiplication was carried out on 4.44 μM BA + 0.5 μM NAA medium, and semisolid and non-aerated liquid systems were compared for improving shoot *** of adventitious shoots was evaluated on medium containing NAA or Indole-3-butyric acid-IBA(5 and16 μM). Callogenesis was obtained from both types of explants, although shoot formation was only obtained from leaf-derived calli. Shoot proliferation on 4.44 μM BA+0.5 μM NAA resulted in the most shoots/***-aerated liquid medium was more efficient in promoting shoot multiplication(53.5 shoots/callus) than was semisolid medium(28.5 shoots/callus). levels of phenolic compounds were significantly reduced in the shoots cultivated in liquid medium. Efficient rooting(76%) was obtained using 16 μM IBA.

关键词： Adventitious shoots Callus liquid medium Micropropagation Phenolic compounds Rooting

Clustering-based adaptive low-power subframe configuration with load-aware offsetting in dense heterogeneous networks

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Digital Communications and Networks 2022年第5期8卷 843-852页

作者： Dinkisa A.Bulti Jyri Hämäläinen Beneyam B.Haile Yihenew Wondie School of Electrical and Computer Engineering Addis Ababa Institute of Technology(AAiT)Ethiopia Department of Communication and Networking Aalto UniversityFinland

Heterogeneous Networks(HetNets)and cell densification represent promising solutions for the surging data traffic demand in wireless *** dense HetNets,user traffic is steered toward the low-Power Node(lPN)when possible to enhance the user throughput and system capacity by increasing the area spectral ***,because of the transmit power differences in different tiers of HetNets and irregular service demand,a load imbalance typically exists among different serving *** offload more traffic to lPNs and coordinate the Inter-Cell Interference(ICI),Third-Generation Partnership Project(3GPP)has facilitated the development of the Cell Range Expansion(CRE),enhanced Inter-Cell Interference Coordination(eICIC)and Further enhanced ICIC(FeICIC).In this paper,we develop a cell clustering-based load-aware offsetting and an adaptive low-Power Subframe(lPS)*** solution allows the separation of User Association(UA)functions at the User Equipment(UE)and network server such that users can make a simple cell-selection decision similar to that in the maximum Received Signal Strength(max-RSS)based UA scheme,where the network server computes the load-aware offsetting and required lPS periods based on the load conditions of the *** proposed solution is evaluated using system-level simulations wherein the results correspond to performance changes in different service *** show that our method effectively solves the offloading and interference coordination problems in dense HetNets.

关键词： Heterogeneous networks(HetNets) 5G lTE-AUser association Interference coordination load balancing Cell range expansion Almost blank subframe Further enhanced ICIC low-power subframe

Comparison of a Full Second-Order Moment Model and an Algebraic Stress Two-Phase Turbulence Model for Simulating Bubble-liquid Flows in a Bubble Column

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Chinese Journal of Chemical Engineering 2002年第2期10卷 142-148页

作者：周力行杨玟廉春英 l.S.Fan D.J.lee Department of Engineering Mechanics Tsinghua University Beijing 100084 China Department of Chemical Engineering The Ohio State University USA

A full second-order moment (FSM) model and an algebraic stress (ASM) two-phase turbulence modelare proposed and applied to predict turbulent bubble-liquid flows in a 2D rectangular bubble column. Predictiongives the bubble and liquid velocities, bubble volume fraction, bubble and liquid Reynolds stresses and bubble-liquidvelocity correlation. For predicted two-phase velocities and bubble volume fraction there is only slight differencebetween these two models, and the simulation results using both two models are in good agreement with the particleimage velocimetry (PIV) measurements. Although the predicted two-phase Reynolds stresses using the FSM are insomewhat better agreement with the PIV measurements than those predicted using the ASM, the Reynolds stressespredicted using both two models are in general agreement with the experiments. Therefore, it is suggested to usethe ASM two-phase turbulence model in engineering application for saving the computation time.

关键词： second-order moment model two-phase turbulence bubble-liquid flow bubble column