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A hig. performance g.s–liquid two-phase flow meter based on g.mma-ray attenuation and scattering

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Nuclear Science and Techniques 2017年第11期28卷 271-279页

作者： g. H. Roshani E. Nazemi Electrical Eng.neering.Department Kermanshah University of Technology Kermanshah Iran Nuclear Science and Technolog. Research Institute TehranIran Radiation Application Department Shahid Beheshti University Tehran Iran

The ability to precisely estimate the void fraction of multiphase flow in a pipe is very important in the petroleum industry. In this paper, an approach based on our previous works is proposed for predicting.the void fraction independent of flow reg.me and liquid phase density chang.s in g.s–liquid two-phase flows. Implemented technique is a combination of dual modality densitometry and multi-beam g.mma-ray attenuation techniques. The detection system is comprised of a sing.e energ. fan beam,two transmission detectors, and one scattering.detector. In this work, artificial neural network(ANN) was also implemented to predict the void fraction percentag. independent of the flow reg.me and liquid phase density chang.s. Reg.stered counts in three detectors and void fraction percentag. were utilized as the inputs and output of ANN, respectively. By applying.the proposed methodolog., the void fraction was estimated with a mean relative error of less than just 1.2480%.

关键词： g.mma-ray Transmission and scattering Artificial neural network Density independent Flow reg.me independent Void fraction

Artificial neural network-based merg.ng.score for Meta search eng.ne

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Journal of Central South University 2016年第10期23卷 2604-2615页

作者： P.Vijaya g.Raju Santosh Kumar ray Karpag.m University Coimbatore TamilNadu India Faculty of Eng.neering.and Technolog. Associate Professor Department of Information Technology Kannur University Kannur Kerala-670 567 India Department of Information Technolog. Al Khawarizmi International College Al Alin UAE

Several users use metasearch eng.nes directly or indirectly to access and g.ther data from more than one data sources. The effectiveness of a metasearch eng.ne is majorly determined by the quality of the results and it returns and in response to user queries. The rank ag.reg.tion methods which have been proposed until now exploits very limited set of parameters such as total number of used resources and the ranking. they achieved from each individual resource. In this work, we use the neural network to merg. the score computation module effectively. Initially, we g.ve a query to different search eng.nes and the top n list from each search eng.ne is chosen for further processing.our technique. We then merg. the top n list based on unique links and we do some parameter calculations such as title based calculation, snippet based calculation, content based calculation, domain calculation, position calculation and co-occurrence calculation. We g.ve the solutions of the calculations with user g.ven ranking.of links to the neural network to train the system. The system then rank and merg. the links we obtain from different search eng.nes for the query we g.ve. Experimentation results reports a retrieval effectiveness of about 80%, precision of about 79% for user queries and about 72% for benchmark queries. The proposed technique also includes a response time of about 76 ms for 50 links and 144 ms for 100 links.

关键词： metasearch eng.ne neural network retrieval of documents ranking.list

Delay-rang.-dependent Stability Criterion for Interval Time-delay Systems with Nonlinear Perturbations

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International Journal of Automation and computing 2011年第1期8卷 141-146页

作者： K.Ramakrishnan g.ray Department of Electrical Eng.neering Indian Institute of Technology

In this paper, we consider the problem of robust stability for a class of linear systems with interval time-varying.delay under nonlinear perturbations using.Lyapunov-Krasovskii （LK） functional approach. By partitioning.the delay-interval into two seg.ents of equal leng.h, and evaluating.the time-derivative of a candidate LK functional in each seg.ent of the delay-interval, a less conservative delay-dependent stability criterion is developed to compute the maximum allowable bound for the delay-rang. within which the system under consideration remains asymptotically stable. In addition to the delay-bi-seg.entation analysis procedure, the reduction in conservatism of the proposed delay-dependent stability criterion over recently reported results is also attributed to the fact that the time-derivative of the LK functional is bounded tig.tly using.a newly proposed bounding.condition without neg.ecting.any useful terms in the delay-dependent stability analysis. The analysis, subsequently, yields a stable condition in convex linear matrix inequality （LMI） framework that can be solved non-conservatively at boundary conditions using.standard numerical packag.s. Furthermore, as the number of decision variables involved in the proposed stability criterion is less, the criterion is computationally more effective. The effectiveness of the proposed stability criterion is validated throug. some standard numerical examples.

关键词： Lyapunov-Krasovskii (LK) functional delay-rang.-dependent stability linear matrix inequality (LMI) interval timevarying.delay nonlinear perturbations.

Could brig.t γ-ray burst optical transients have been recorded historically?

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Research in Astronomy and Astrophysics 2012年第3期12卷 260-268页

作者： Richard g. Strom Fu-Yuan Zhao Cheng.Min Zhang National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Netherlands Institute for Radio Astronomy （ASTRON） EO. Box 2 7990 AA DwingelooNetherlands Astronomical Institute University of Amsterdam Netherlands James Cook University Townsviile Queensland Australia

The brig.test optical flash from a γ-ray burst （g.B） was, briefly, a naked- eye object. Several other g.Bs have produced optical transients only slig.tly fainter. We arg.e that, based upon the recently accumulated data from hundreds of g.B transients, many such optical events should have been visible to the unaided eye in the course of human history. The most likely repositories of such observations are histor- ical records from the Orient, and we have located and discuss a number of candidates. We also consider the value of such observations, should any very likely ones be uncovered, to modern astrophysics.

关键词： γ-rays: bursts—optical transients—historical records

Mag.etic Islands Observed by a Fast-Framing.Tang.ntially Viewing.Soft X-ray Camera on LHD and TEXTOR

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Plasma Science and Technolog. 2006年第1期8卷 45-49页

作者： S. OHDACHI K. TOI g. FUCHS TEXTOR Team National Institute for Fusion Science Toki 509-5292 Gifu Japan Institut fiir Plasma physik Forschungszentrum Jfilich GmbH Euratom Association D-52425 Jülich Germany

The formation of mag.etic islands within plasmas confined mag.etically within the tori has sig.ificant influence upon their confinement and stability. To obtain an experimental insig.t into the formation and dynamics of such island structures we employed a fast framing.camera viewing.the plasma tang.ntially in the toroidal direction. The toroidal viewing.direction g.ves the advantag. in that the islands are viewed almost tang.ntially and this g.eatly facilitates the reconstruction of the local data from the line integ.ated ones. We discuss an effective method to do inversion. To study the fluctuations seen in the video imag.s we perform a sing.lar value decomposition, and then we use a truncated least square method to infer their pictures in space.

关键词： mag.etic island, fluctuation measurement tomog.aphy

Advances in Tropical Soil Characterization via Portable X-ray Fluorescence Spectrometry

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Pedosphere 2019年第4期29卷 468-482页

作者： Elen A. SILVA David C. WEINDORF Serg.o H. g. SILVA Bruno T. RIBEIRO g.ovana C. POg.ERE Teotonio S. CARVALHO Mariana g. M. g.NQALVES Luiz R. g. g.ILHERME Nilton CURI Department of Soil Science Federal University of Lavras Lavras 37200-000 (Brazil) Department of Plant and Soil Science Texas Tech University Texas 79409-2122 (USA)

Portable X-ray fluorescence(pXRF) spectrometers can be used to determine the elemental composition easily, rapidly, and without using.chemical reag.nts, which is very important for tropical reg.ons due to the lack of detailed soil characterization data. Moreover,pXRF data can be used to predict the results of more expensive, time-consuming. and conventional laboratory analyses. This study soug.t to determine the elemental composition of various soil profiles using.pXRF. Two operational modes(Trace Mode and g.neral Mode) and two scanning.time(30 and 60 s) were assessed to determine their effects on the correlation of pXRF dataset with respect to conventional inductively coupled plasma(ICP)-optical emission spectrometry analysis. This relationship has been reported in previous studies, however, few studies were performed on tropical soils, which are unique. Furthermore, such relationships establish the viability of developing.prediction models directly from pXRF data. Linear reg.ession was applied to develop calibration models for the prediction of ICP analysis results and exchang.able and available elemental contents based on pXRF data. Hig. coefficients of determination(R^2) were obtained for Ca(0.87), Cu(0.90), Fe(0.95), Mn(0.85), Cr(0.95), V(0.72), and Ni(0.90), with adequate validation. Statistically sig.ificant results were not found for Al, K, Zn, Ti, and Zr. The models predicting.the exchang.able Ca based on the total Ca from p XRF reached an R^2 of up to 0.85. Operational modes influenced the pXRF results. Our results illustrate that pXRF holds g.eat promise for tropical soil characterization and the development of prediction models, justifying.the need for larg.r-scale studies in tropical countries worldwide.

关键词： elemental composition exchang.able Ca inductively coupled plasma operational mode prediction models scanning time soil analysis total elemental content

Meta-analysis of electron cyclotron resonance absorption features detected in hig.-mass X-ray binaries

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Research in Astronomy and Astrophysics 2019年第10期19卷 69-74页

作者： Dimitris M. Christodoulou Silas g. T. Laycock Demosthenes Kazanas Lowell Center for Space Science and Technolog. University of Massachusetts Lowell Lowell MA 01854 USA Department of Mathematical Sciences University of Massachusetts Lowell Lowell MA 01854 USA Department of Physics & Applied Physics University of Massachusetts Lowell Lowell MA 01854 USA NASA g.ddard Space Flig.t Center Laboratory for High-Energy Astrophysics Code 663 Greenbelt MD 20771 USA

Using.recent compilations of detailed X-ray observations and spectral models of exceptional quality, we record the electron cyclotron resonance absorption(ECRA) features that have been detected in 45 pulsating.hig.-mass X-ray binaries(HMXBs) and ultraluminous X-ray(ULX) sources harboring.neutron stars, althoug. seven of these detections are still questionable and another 21 are sing.e and/or not independently confirmed. From the comprehensive catalog. of Jaisawal & Naik and Staubert et *** from several additional recent observations, we produce two lists of HMXB ECRA sources: a list of 17 sources in which multiple ECRA lines or sing.e very low-energ. lines are seen, in which we can reasonably assume that the lowest energ. reveals the fundamental cyclotron level for each source;and a"contaminated" list of 38 sources including.the 21 detections of sing.e ECRA lines that may(not) be hig.erlevel harmonics. Both lists confirm a previous result that we have obtained independently by modeling.the propeller lines of Mag.llanic HMXB pulsars: the surface dipolar mag.etic fields B*of HMXB neutron stars are seg.eg.ted around five distinct values with B*= 0.28 ± 0.08, 0.55 ± 0.11, 1.3 ± 0.37, 3.0 ± 0.68 and 7.9 ± 3.1, in units of Tg. However, an explanation of this phenomenon is currently lacking. We have found no correlation between these B*values and the corresponding.observed spin periods, spin period derivatives, orbital periods, maximum X-ray luminosities, neutron star masses or companion star masses.

关键词： stars mag.etic fields-stars neutron-X-rays binaries

Oblique Drop Impact on Deep and Shallow Liquid

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Communications in Computational Physics 2012年第4期11卷 1386-1396页

作者： B.ray g.Biswas A.Sharma Department of Mechanical Eng.neering Indian Institute of Technology KanpurKanpur 208016India CSIR-Central Mechanical Eng.neering.Research Institute Durgapur 713209India Department of Chemical Eng.neering Indian Institute of Technology KanpurKanpur 208016India

Numerical simulations using.CLSVOF(coupled level set and volume of fluid)method are performed to investig.te the coalescence and splashing.reg.mes when a spherical water drop hits on the water surface with an imping.ment *** ang.e is the ang.e between the velocity vector of primary drop and the normal vector to water *** effect of imping.ment ang.e,impact velocity and the heig.t of targ.t liquid are carried *** imping.ment ang.e is varied from 0o to 90o showing.the g.adual chang. in *** formation of ship pro like shape,liquid sheet,secondary drops and crater are *** heig.t,crater displacement,crown heig.t and crown ang.e are calculated and the chang. in the parameters with chang. in imping.ment ang.e is noted.

关键词： Coupled level set and volume of fluid method drop impact imping.ment ang.e Weber number

Hig.-pressure investig.tions on Piplia Kalan eucrite meteorite using.in-situ X-ray diffraction and ^(57)Fe Mssbauer spectroscopic technique up to 16 g.a

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g.oscience Frontiers 2016年第2期7卷 265-271页

作者： Usha Chandra K.K. Pandey g. Parthasarathy Surinder M. Sharma Department of Physics University of Rajasthan Jaipur 302 004 India Hig. Pressure & Synchrotron Radiation Physics Division Bhabha Atomic Research Centre Trombay Mumbai 400 085 India CSIR-National g.ophysical Research Institute Uppal Road Hyderabad 500 007 India

We report here hig.-pressure investig.tions on Piplia Kalan eucrite-a member of HED （Howardite -Eucrite-Diog.nite） family from asteroid 4-Vesta based on synchrotron X-ray diffraction （up to 16 g.a） and ^57Fe Mossbauer spectroscopy （up to 8 g.a）. Dominant with anorthite-rich plag.oclase, pig.onite-rich pyroxene and clino-ferrosilite, the sample displayed various phase transitions attaining.amorphous character at 16 g.a. These phase transitions of individual components could be explained simultaneously throug. variations in hig.-pressure XRD patterns and the Mossbauer parameters. Most prominent P21/c to C2/c transition of pig.onite and ferrosilite was exhibited both as sudden variation in Mossbauer parameters and population inversion of Fe^2＋ in M1 and M2 sites between 2.9 and 3.8 g.a and variation in intensity profile in XRD patterns at 3.56 g.a. Anorthite seemed to respond more to such impact than other components in the sample. Complete amorphization in anorthite which occurred at lower pressure of - 12 g.a implied residual stress experienced due to shock impact. The presence of hig. pressure （monoclinic） phase of pig.onite and ferrosilite at ambient condition in this eucrite sample confirmed earlier sug.estions of an early shock event. This report is an attempt to emphasize the role of anorthite in the determination of the residual stress due to impact process in the parent body thus to understand the behavioral differences among.t HED members.

关键词： Meteorites Hig. pressure X-ray diffraction Mossbauer spectroscopy Eucrites synchrotron radiation Ferrosilite