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Simultaneous observations of a pair of kilohertz QPOs and a plausible 1860Hz QPO from an accreting neutron star system

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research in Astronomy and Astrophysics 2010年第3期10卷 227-234页

作者： Sudip Bhattacharyya department of Astronomy and Astrophysics Tata Institute of Fundamental Research

We report an indication （3.22 or） of ≈ 1860 Hz quasi-periodic oscillations from a neutron star low-mass X-ray binary 4U 1636-536. If confirmed, this will be by far the highest frequency feature observed from an accreting neutron star system, and hence could be very useful in understanding such systems. This plausible timing feature was observed simultaneously with lower （≈ 585 Hz） and upper （≈ 904 Hz） kilohertz quasi-periodic oscillations. The two kilohertz quasi-periodic oscillation frequencies had a ratio of ≈ 1.5, and the frequency of the alleged ≈ 1860 Hz feature was close to the triple and the double values of these frequencies. This can be useful for constraining the models of all the three features. In particular, the ≈ 1860Hz feature could be （1） from a new and heretofore unknown class of quasi-periodic oscillations, or （2） the first observed overtone of lower or upper kilohertz quasi-periodic oscillations. Finally, we note that, although the relatively low significance of the ≈ 1860 Hz feature argues for caution, even a 3.22 σ feature at such a uniquely high frequency should be interesting enough to spur a systematic search in the archival data, as well as to scientifically motivate sufficiently large timing instruments for the next generation X-ray missions.

关键词： accretion accretion disks -- methods: data analysis -- relativity -- stars: neutron -- X-rays: binaries -- X-rays: individual (4U 1636-536)

Main Controlling Factors and Dominant Reservoir Series Analysis of Es_3 in the Qibei Area of Qikou Sag

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Acta Geologica Sinica(English Edition) 2013年第1期87卷 219-231页

作者： PU Xiugang HAN Wenzhong HUA Shuangjun ZHANG Wei CHEN Changwei research department of fundamental Geology Exploration and Development Research InstituteDagang Oilfield

Based on analysis of geophysical data such as core observation, rock slices identification, physical property, scanning electron microscope, X-ray diffraction, logging data etc., 16 factors of sedimentation, diagenesis, fluid pressure, and their relationships with reservoir physical property were analyzed, and the results indicate sedimentation is the internal factor controlling the reservoir property, diagenesis is the external and final decisive factor and abnormal fluid pressure is an important factor preserving the deep reservoir property. Quantitative characterization of diagenesis indicates that compaction and dissolution are more important than cementation and they respectively cause porosity change of-23.6% and 7.7% and -6.2%. Through optimizing 11 main controlling factors and constructing reservoir evaluation index （REI） according to the hierarchical cluster and principal component analysis, reservoir classification standard was established and reservoirs were divided into four classes. The studies show that Es~ SQ4 consists mainly of class I and II, while Es~ SQ6 is mainly of class III and II; the favorable zone is the north and south slope of Qibei sub-sag and the Liujianfang fault-nose. The successful application of the quantitative and comprehensive evaluation in the Qibei area verifies the advanced, practicable method of less artificial factor is suitable for the low porosity and permeability reservoir.

关键词： single factor analysis quantitative characterization comprehensive and quantitativereservoir evaluation Shahejie Formation Qibei area Qikou sag

Generation of brain vascular heterogeneity:recent advances from the perspective of angiogenesis

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Neural Regeneration research 2025年第7期20卷 2013-2014页

作者： Nathanael J.Lee Ryota L.Matsuoka department of Neurosciences Lerner Research InstituteCleveland ClinicClevelandOHUSA department of Molecular Medicine Cleveland Clinic Lerner College of MedicineCase Western Reserve UniversityClevelandOHUSA

Heterogeneous proper t i es of vascular endothelial cells in the brain:The brain displays large energy dynamics and consumption,and this high level of metabolic demands is fulfilled by a continuous supply of glucose and oxygen through its vascular *** vasculature consists of highly divergent blood vessel branches,giving rise to a dense network of capillaries that supply blood to all cells across the *** elaborated vascular network is thought to develop via angiogenesis,a process in which new blood vessels grow from pre-existing *** capillaries exhibit organotypic features distinct from other tissues and are formed primarily by two major endothelial cell(EC)types:those that form the semi-permeable blood-brain barrier(BBB)and those that develop highly permeable pores known as fenestrae(Matsuoka et al.,2022).The structural and functional differences between BBB and fenestrated vascular ECs represent a fundamental feature of brain vasculature and form the foundation for both brain function and homeostasis.

关键词： angiogenesis homeostasis network

A truncated accretion disk in the galactic black hole candidate source H1743–322

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research in Astronomy and Astrophysics 2009年第8期9卷 901-910页

作者： Kandulapati Sriram Vivek Kumar Agrawal Arikkala Raghurama Rao department of Astronomy Osmania University department of Astronomy and Astrophysics Tata Institute of Fundamental Research Indian Space research Organization

To investigate the geometry of the accretion disk in the source H1743-322, we have carried out a detailed X-ray temporal and spectral study using RXTE pointed observations. We have selected all data pertaining to the Steep Power Law （SPL） state during the 2003 outburst of this source. We find anti-correlated hard X-ray lags in three of the observations and the changes in the spectral and timing parameters （like the QPO frequency） confirm the idea of a truncated accretion disk in this source, Compiling data from similar observations of other sources, we find a correlation between the fractional change in the QPO frequency and the observed delay. We suggest that these observations indicate a definite size scale in the inner accretion disk （the radius of the truncated disk） and we explain the observed correlation using various disk parameters like Compton cooling time scale, viscous time scale etc..

关键词： accretion, accretion disk -- binaries close -- stars individual (H1743-322)-- X-rays binaries

Molecular modeling of oscillating GHz electric field influence on the kinesin affinity to microtubule

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Chinese Physics B 2015年第8期24卷 239-242页

作者： H.R.Saeidi S.S.Setayandeh A.Lohrasebi department of Physics University of Isfahan Computational Nano-Bioelectromagnetics research Group School of Nano-Science Institute for Research in Fundamental Sciences (IPM)

Kinesin is a microtubule-associated motor protein which can respond to the external electric field due to its *** a molecular dynamics simulation method, the effect of such a field on the affinity of kinesin to the α β-tubulin is investigated in this study. To consider kinesin affinity, the system is exposed to an electric field of 0.03 V/nm with frequency values of 1, 2,..., 9, and 10 GHz. It is found that the applied electric field can change kinesin affinity to the *** changes could perturb the normal operation of kinesin, such as the processive motility of kinesin on the microtubule.

关键词： kinesin affinity oscillating electric field molecular dynamic αβ-tubulin dimer

Higher-Dimensional Kaluza-Klein Theory in Weitzenbock Space

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Science China Mathematics 1993年第2期36卷 201-208页

作者：吴又麟 Henan fundamental and Applied Science research Institute department of Physics Zhengzhou University Zhengzhou 450052 PRC

It is proved that the action of the higher-dimensional gravity in Weitzenb(?)ck space reduces to the sum of the action of gravity in four-dimensional space-time and that of gauge fields. In this sense we conclude that... 详细信息

关键词： Weitzenbock space Kaluza-Klein theory parallel vector fields torsion tensor.

Multiple Solutions for a Quasilinear Second Order Differential Equation Depending on a Parameter

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Acta Mathematicae Applicatae Sinica 2016年第1期32卷 199-208页

作者： SHAPOUR HEIDARKHANI department of Mathematics Faculty of SciencesRazi University School of Mathematics Institute for Research in Fundamental Sciences(IPM)

The purpose of this paper is to use a very recent three critical points theorem due to Bonanno and Marano to establish the existence of at least three solutions for the quasilinear second order differential equation on a compact interval[a,b] R{-u＇＇=（λf（x,u）＋g（u））h（u＇）,in（a,b）,u（a）=u（b）=0under ppropriate *** exhibit the existence of at least three（weak）solutions and,and the results are illustrated by examples.

关键词： Dirichlet problem critical point three solutions multiplicity results variational methods

Determination of the strong coupling constant using available experimental data

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Chinese Physics C 2010年第9期34卷 1485-1487页

作者： S.Atashbar Tehrani A.N.Khorramian School of Particles and Accelerators Institute for Research in Fundamental Sciences (IPM) Physics department Semnan University

We determine the strong coupling constant α s up to 4-loop in perturbative *** QCD requires the measurement of α s over ranges of energy *** this analysis,the value of α s is determined from the unpolarized structure functions data points by minimizing the χ ^2 function between the theory result and experimental *** perturbative QCD calculations from threshold corrections,we obtain α s （M 2 Z ） = 0.1139±0.0020 at N ^3 LO which is in good agreement with the very recently results from the inclusive jet cross section in pp collisions at√ s=1.96 TeV.

关键词： strong coupling DIS data N ^3 LO

Jacobi polynomials and non-singlet structure function F_2 (x,Q^2) up to N^3LO

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Chinese Physics C 2010年第9期34卷 1479-1481页

作者： Ali N.Khorramian S.Atashbar Tehrani Physics department Semnan University School of Particles and Accelerators Institute for Research in Fundamental Sciences (IPM)

In this paper we present the non-singlet QCD analysis to determine valence quark distribution up to four *** obtain the fractional difference between the 4-loop and the 1-,2and 3-loop presentations of xu v （x,Q^2） a... 详细信息

关键词： PDFs DIS data QCD fit