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SOME EXACt SOLUtIONS OF 3-DIMENSIONAL ZERO-PRESSURE GAS DYNAMICS SYStEM

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Acta Mathematica Scientia 2011年第6期31卷 2107-2121页

作者： k.t. Joseph Manas R. Sahoo School of Mathematics Tata Institute of Fundamental Research

the 3-dimensional zero-pressure gas dynamics system appears in the modeling for the large scale structure formation in the universe. the aim of this paper is to construct spherically symmetric solutions to the system. the radial component of the velocity and density satisfy a simpler one dimensional problem. First we construct explicit solutions of this one dimensional case with initial and boundary conditions. then we get special radial solutions with different behaviours at the origin.

关键词： zero-pressure gas dynamics spherically symmetric solutions

An Exact Anisotropic Quark Star Model

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Chinese Journal of Astronomy and Astrophysics 2002年第3期2卷 248-259页

作者： M.k.Mak t.Harko DepartmentofPhysics TheHongKongUniversityofScienceandTechnologyClearWaterBayHongKong DepartmentofPhysics TheUniversityofHongKongPokfulamHongKong

We present an exact analytical solution of the gravitational field equations describing a static spherically symmetric anisotropic quark matter distribution. the radial pressure inside the star is assumed to obey a linear equation of state, while the tangential pressure is a complicated function of the radial coordinate. In order to obtain the general solution of the field equations a particular density profile inside the star is also assumed. the anisotropic pressure distribution leads to an increase in the maximum radius and mass of the quark star, which in the present model is around three solar masses.

关键词： Stars - quark: interior solution: anisotropy

Early Detection of Heartbeat from Multimodal Data Using RPA Learning with kDNN-SAE

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Computer Systems Science & Engineering 2023年第4期45卷 545-562页

作者： A.k.S.Saranya t.Jaya Department of Electronics and Communication Engineering Ponjesly College of EngineeringNagercoilIndia Department of Electronics and Communication Engineering CSI Institute of TechnologyNagercoilIndia

Heartbeat detection stays central to cardiovascular an electrocardiogram(ECG)is used to help with disease diagnosis and *** Convolutional Neural Network(CNN)-based methods suffer from the less generalization problem thus;the effectiveness and robustness of the traditional heartbeat detector methods cannot be *** contrast,this work proposes a heartbeat detector krill based Deep Neural Network Stacked Auto Encoders(kDNN-SAE)that computes the disease before the exact heart rate by combining features from multiple ECG *** are classified independently and multiple signals are fused to estimate life threatening conditions earlier without any error in classification of heart *** work contained training and testing stages,in the preparation part at first the Adaptive Filter Enthalpy-based Empirical Mode Decomposition(EMD)is utilized to eliminate the motion artifact in the *** that point,the robotic process automation(RPA)learning part extracts the effective features are extracted,and normalized the value of the feature then estimated utilizing the RPA loss *** last kDNN-SAE prepared training for the data stored in the *** the subsequent stage,input signal compute motion artifact and RPA Learning the evaluation part determines the detection of *** early diagnosis of heart failures is an essential *** results of the experiments show that our proposed method has a high score outcome of *** to the CIF,which reaches *** CNN and Artificial Neural Network(ANN)had less score 0.95115 and 0.90147.

关键词： Deep neural network krill herd optimization stack auto-encoder adaptive filter enthalpy based empirical mode decomposition robotic process automation

Bi-based superconductors fabricated in high magnetic fields

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中国有色金属学会会刊：英文版 2006年第B01期16卷 11-19页

作者： LU XY A. NAGAtA k. SUGAWARA k. WAtANABE t. NOJIMA Faculty of Engineering and Resource Science Akita University Akita 010-8502 Japan Institute for Materials Research Tohoku University Sendai 980-8577 Japan Center for Low temperature Science Tohoku University Sendai 980-8577 Japan

the microstructure and superconducting properties of Bi-2223 superconductor fabricated in high magnetic fields were investigated. the results shows that the Bi-2212 grains with their c-axis parallel to the magnetic field were formed after the partial-melting and solidification in 8 t magnetic field, and transformed into the Bi-2223 grains with c-axis alignment during the further sintering process at 840 ℃ without magnetic field. the conversion of Bi-2212 grains to Bi-2223 grains has the heredity in grain alignment. the mixed structures of the Bi-2223 and the Bi-2212 grains with their c-axis parallel to the magnetic field are formed in samples sintered at 850?855 ℃ in 10 t magnetic field. When sintered in 10 t below 845 ℃, a high proportion of Bi-2223 phase is obtained, however no preferred orientation is observed. the Bi-2223 grains with their c-axis parallel to the axial direction of the vertical tube furnace are formed not only on the surface, but also in the center of the sample sintered at 850 ℃ for 120 h in a 15 ℃/cm temperature gradient without magnetic field. Moreover, the samples sintered in the temperature gradient and in a 10 t magnetic field have a stronger c-axis alignment of Bi-2223 phase.

关键词：铋基超导体制造铋-2223 磁场显微结构

Relationship between Primary Crystal temperature and Carbon Equivalent in Cast Iron

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Journal of Materials Science & technology 2008年第3期24卷 325-326页

作者： t.kanno t.kikuchi k.Hayashi Y.Maruyama kimura Chuzosho Co.Ltd. 1157 Nagasawa Shimizu-choShizuoka-ken

CE （=%C＋（1/3）x（%Si）） does not suit experiment results in many cases. In this work, the effect of alloy elements on primary crystal temperature was measured and the relationship between primary crystal temperature （tc） and carbon equivalent （CEL） was investigated. the results show that tc （Celsius degree） = 1650-110 × （%C） -25 × （%Si）＋3 × （%Mn） -35 × （%P） -71 × （%5）-2 × （%Ni） -7 × （%Cr）; CEL=%C ＋ 0.23×（%Si）-0.03× （%Mn）＋0.32×（%P）＋0.64×（%S）＋0.02×（%Ni）＋0.06×（%Cr）. that is, in hypo eutectic composition, carbon equivalent should be calculated with CEL=%C＋ 0.23×（%Si）, not with CE=%C＋（1/3） x（%Si）.

关键词： Carbon equivalent Cast iron Primary crystal temperature Hypo eutectic composition

Gamma-Ray Bursts: Afterglows and Central Engines

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Chinese Journal of Astronomy and Astrophysics 2001年第1期1卷 1-20页

作者： k.S.Cheng t.Lu DepartmentofPhysics UniversityofHongKongPokfulamRoadHongKong DepartmentofAstronomy NanjingUniversit

Gamma-ray bursts (GRBs) are the most intense transient gamma-ray events in the sky; this, together with the strong evidence (the isotropic and inhomogeneous distribution of GRBs detected by BAStE) that they are located at cosmological distances, makes them the most energetic events ever known. For example, the observed radiation energies of some GRBs are equivalent to the total convertion into radiation of the mass energy of more than one solar mass. this is thousand times stronger than the energy of a supernova explosion. Some unconventional energy mechanism and extremely high conversion efficiency for these mysterious events are required. the discovery of host galaxies and association with supernovae at cosmological distances by the recently launched satellite of BeppoSAX and ground based radio and optical telescopes in GRB afterglow provides further support to the cosmological origin of GRBs and put strong constraints on their central engine. It is the aim of this article to review the possible central engines, energy mechanisms, dynamical and spectral evolution of GRBs, especially focusing on the afterglows in multi-wavebands.

关键词： gamma-rays: bursts - shock waves - ISM: jets and outflows- radiation mechanisms: non-thermal

Nonlinear Behaviour of Coflexip Risers

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China Ocean Engineering 2001年第4期16卷 479-490页

作者： kamal Zare t. k. Datta Department of Civil Engineering Indian Institute of Technology Hauzkhas New Delhi-110016 India Department of Civil Engineering Indian Institute of Technology Hauzkhas New Delhi-110016 India

A modified Newton-Raphson iterative technique is formulated for obtaining the static configuration of the Lazy 'S' flexible marine riser between the floater and mid-arch buoy under its submerged self weight and the applied top tension. the geometrically non-linear problem is solved by finite difference with the above technique. the problem is formulated as a regular boundary value problem with specified moments and deflections at both ends. Usually the bending stiffness of the flexible riser made of Coflexip pipe is very low. By use of the above analysis, several flexible riser configurations are analyzed and their characteristic behaviors are investigated. Also, changes in the riser characteristics due to quasi-static motion of the floater end are estimated for the safety of the riser layout.

关键词： lazy 'S' riser coflexip pipe flexible riser mid-arch buoy geometric nonlinearily

the law as it relates to subsidence as a consequence of mining activity in Britain

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中国有色金属学会会刊：英文版 2005年第S1期15卷 258-261页

作者： G. t. Powell k. Leighfield University of Glamorgan Wales United KingdomUniversity of Glamorgan Wales United Kingdom

Subsidence as a consequence of mining activity has been an onerous problem associated with mineral extraction in Britain. Mining law as it relates to subsidence has developed over several centuries. this paper will outline the legal implications for mineral subsidence and compensation, considering both common law and statute. Particular reference is made to the extraction of coal, salt in brine, protection of public utilities, working facilities orders, ironstone and ancient mining rights.

关键词： subsidence compensation coal working facilities orders

Magnetic Properties of Nd-Fe-B Sintered Magnet Powders Recovered by Yb Metal Vapor Sorption

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Journal of Rare Earths 2004年第1期22卷 152-156页

作者： Horikawa t Itoh M Suzuki Shunji Machida k Collaborative Research Center for Advanced Science and technology Collaborative Research Center for Advanced Science and TechnologyCollaborative Research Center for Advanced Science and TechnologyCollaborative Research Center for Advanced Science and Technology Osaka University Osaka 565-0871 Japan Osaka University Osaka 565-0871 Japan Osaka University Osaka 565-0871 Japan Osaka University Osaka 565-0871 Japan

Fine ground powders of Nd-Fe-B sintered magnet bulks (particle size=46～125 μm in diameter) were coated and alloyed with Yb metal by sorbing them. A significant recovery of the decreased magnetic properties of the ground powders (remanence B r=～0.95 t, coercivity H cj =～227 kA·m -1 and maximum energy product (BH) max=～48 8 kJ·m -3) was observed in accordance with increasing temperature up to 800 ℃. the sorbing temperature and time for Yb metal vapor were optimized and after heating at 800 ℃ for 90 min and annealing subsequently at 610 ℃ for 60 min, the B r, H cj and (BH) max values were increased to be 0.98 t, 712 kA·m -1 and 173 kJ·m -3, respectively. From the microstructural characterizations of resulting samples by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron probe X-ray microanalyzer (EPMA), it is found that the sorbed Yb metal uniformly covers the surface and diffuses to the Nd-rich grain boundary of fine ground powders of Nd-Fe-B sintered magnet bulks forming a (Nd,Yb)Fe 2 phase.

关键词： metal materials Nd 2Fe 14B sintered magnets metal vapor sorption magnetic properties recovery rare earths