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dephosphorization Thermodynamics of Crude Steel Using CaO-Based Flux

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Journal of iron and Steel Research international 2003年第3期10卷 10-15页

作者： YANG Yin-dong McKague A R McLean A Sommerville i d University of Toronto

The experiments were carried out at 1 175-1 450 ℃ to study the phosphorus distribution ratio between molten Ca O-based slags and carbon saturated hot metal. The phosphate capacity of the slags and the activity coefficient of PO2. 5were calculated from the phosphorus distribution ratio. The effect of addition of Ca F2 and / or Ca Cl2 on the thermodynamic properties of slags was discussed. The correlation of optical basicity with phosphate capacity of slags was studied,and the dephosphorization ability of Ca O-based fluxes with various additives was compared with the results from different studies.

关键词： phosphorus activity coefficient phosphate capacity optical basicity lime-based flux clean steel

Solution of Spin and Pseudo-Spin Symmetric dirac Equation in (1＋1) Space-Time Using Tridiagonal Representation Approach

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Communications in Theoretical Physics 2018年第3期69卷 241-256页

作者： i.A.Assi A.d.Alhaidari H.Bahlouli department of Physics and Physical Oceanography Memorial University of Newfoundland St. John's NL A1B3XT Canada Saudi Center for Theoretical Physics P.O. Box 32741 Jeddah 21438 Saudi Arabia Physics department King Fahd University of Petroleum & Minerals Dhahran 31261 Saudi Arabia

The aim of this work is to find exact solutions of the dirac equation in(1+1) space-time beyond the already known *** consider exact spin(and pseudo-spin) symmetric dirac equations where the scalar potential is equal to plus(and minus) the vector *** also include pseudo-scalar potentials in the *** spinor wavefunction is written as a bounded sum in a complete set of square integrable basis,which is chosen such that the matrix representation of the dirac wave operator is tridiagonal and *** makes the matrix wave equation a symmetric three-term recursion relation for the expansion coefficients of the *** solve the recursion relation exactly in terms of orthogonal polynomials and obtain the state functions and corresponding relativistic energy spectrum and phase shift.

关键词： dirac equation spin and pseudo-spin tridiagonal representations recursion relation orthogonal polynomials

Assessing the Sustainability of Underground Space Usage——A Toolkit for Testing Possible Urban Futures

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Journal of Mountain Science 2011年第2期8卷 211-222页

作者： d.V.L.HUNT i.JEFFERSON C.d.F.ROGERS The University of Birmingham

A description of the future as it might be without forecasts, predictions and trend analysis can be referred to as a 'future scenario'. An abundance of scenarios literature exists in which numerous pictures have been painted of changed future worlds. However, upon closer inspection it becomes apparent that virtually all of this literature refers to changes occurring above ground, ignoring the inevitable consequences (or opportunities) for sustainable use of underground space, not least in densely populated urban areas, some of which may be underlain by complex geological conditions. This paper reports on the development (to date) of an 'Urban Futures' (UF) toolkit for sub-surface environments (including infrastructure and utilities) which, through use of 'key' questions 'sustainable' indicators and a 'contextual' narrative, allows for better definition and measured performance of underground space in the UK, both today and in the future. The toolkit explores possible uses for underground space within 4 plausible and well-cited future scenarios (i.e. New Sustainability Paradigm, Fortress World, Market Forces and Policy Reform). This forms part of a much larger generic toolkit which the UF research team are developing for exploring possible future scenarios over a range of UK urban regeneration case study areas.

关键词： urban futures toolkit underground space sustainability

Morphology,structure and magnetic behavior of orthorhombic and hexagonal HoFeO_(3)synthesized via solution combustion approach

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Journal of Rare Earths 2022年第2期40卷 296-301,I0004页

作者： K.d.Martinson i.S.Kondrashkova M.i.Chebanenko A.S.Kiselev T.Yu Kiseleva V.i.Popkov ioffe institute 26 PoliteknicheskayaSL Petersburg194021Russia Saint Petersburg State institute of Technology 26 MoskovskySt.Petersburg190013Russia Faculty of Physics M.V.Lomonosov State UniversityLeninskie CoryMoscow119991Russia

Nanostructured HoFeO_(3)powders were obtained by solution combustion method at various glycinenitrate ratios(G/N=0.2,0.4,...,1.4).According to X-ray powder diffractometry data,the presence of two modifications of HoFeO_(3)in the synthesized samples was established:orthorhombic(Pbnm)and hexagonal(P63/mmc).The crystallite size of the obtained compositions varies from 62±6 to 29±3 nm,depending on the G/N *** magnetic structure studies,it is found that HoFeO_(3)obtained with a stoichiometric amount of glycine in the reaction solution is in the magnetically ordered state and is represented by a sextet with quadrupole splitting(QS)=0 mm/s,isomeric shift(iS)=0.36 mm/s and effective field strength(Heff)=497 *** to the results of vibrational magnetometry,it is found that the orthoferrites obtained have a ferromagnetic structure,the main parameters of which(Ms,Mr and Hc)systematically change with a change in the redox ratio of the reaction mixture and,as a consequence,their phase composition,and reach maximum values at a G/N ratio=*** the samples obtained with a significant excess and lack of glycine(G/N=0.2 and 1.4),despite their amorphous nature,hysteresis loops characteristic of the ferromagnetic state of the substance is *** is hopeful to obtain a pure hexagonal modification of HoFeO_(3)via heat treatment on amorphous products of glycine-nitrate combustion.

关键词： Crystal structure Rare earth compounds Perovskites Nanomaterials Magnetic materials

Enthalpy of formation of quasicrystalline phase and ternary solid solutions in the Al-Fe-Cu system

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Rare Metals 2006年第5期25卷 608-613页

作者： i.A.Tomilin S.d.Kaloshkin V.V.Tcherdyntsev Moscow State institute of Steel and Alloys (Technologycal University) 119049 Leninsky prosp.4MoscowRussia

Standard enthalpies of formation of quasicrystalline phase and the ternary solid solutions in the Al-Fe-Cu system and the intermetaUic compound FeAi were determined by the means of solution calorimetry. The quasicrystalline phase was prepared using two different methods. The first method （i） consisted of ball milling the mixture of powders of pure aluminum copper and iron in a planetary mill with subsequent compacting by hot pressing and annealing. The second method （Ⅱ） consisted of arc melting of the components in argon atmosphere followed by annealing. The latter method was used for preparing the compound FeAl and the solid solutions. The phases were identified using the XRd method. The enthalpy of the formation was determined for the quasicrystalline phase of the composition Al62Cu25.5Fe12.5 and the temary BCC solid solutions Al35Cu14Fe51, Al40Cu17Fe43, and Al50.4Cu19.6Fe30. The measured enthalpy of formation of the intermetallic compound FeAl is in good agreement with the earlier published data. The enthalpies of formation of the quasicrystalline phases prepared using two different methods are close to each other, namely, -22.7±3.4 （method i） and -21.3±2.1 （method Ⅱ） kJ/mol.

关键词： enthalpy of formation calorimetry quasicrystals Al-Fe-Cu

On the Relationship between Climatic Variables and Pressure Systems over Saudi Arabia in the Winter Season

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Advances in Atmospheric Sciences 2015年第5期32卷 690-703页

作者： H.M.HASANEAN H.abdel BASSET M.A.A.HUSSEiN department of Meteorology Faculty of Meteorology Environment and Arid Land AgricultureKing Abdulaziz University department of Meteorology and Astronomy Faculty of Science Al-Azhar University

The synoptic circulation over Saudi Arabia is complicated and frequently governed by the effect of large-scale pressure systems. in this work, we used NCEP–NCAR global data to illustrate the relationship between climatic variables and the main pressure systems that affect the weather and climate of Saudi Arabia, and also to investigate the influence of these pressure systems on surface air temperature（SAT） and rainfall over the region in the winter season. it was found that there are two primary patterns of pressure that influence the weather and climate of Saudi Arabia. The first occurs in cases of a strengthening Subtropical High（Sub H）, a weakening Siberian High（Sib H）, a deepening of the icelandic Low（ice L）, or a weakening of the Sudanese Low（Sud L）. during this pattern, the Sub H combines with the Sib H and an obvious increase of sea level pressure（SLP） occurs over southern European, the Mediterranean, North Africa, and the Middle East. This belt of high pressure prevents interaction between midlatitude and extratropical systems, which leads to a decrease in the SAT,relative humidity（RH） and rainfall over Saudi Arabia. The second pattern occurs in association with a weakening of the Sub H, a strengthening of the Sib H, a weakening of the ice L, or a deepening of the Sud L. The pattern arising in this case leads to an interaction between two different air masses： the first（cold moist） air mass is associated with the Mediterranean depression travelling from west to east, while the second（warm moist） air mass is associated with the northward oscillation of the Sud L and its inverted V-shape trough. The interaction between these two air masses increases the SAT, RH and the probability of rainfall over Saudi Arabia, especially over the northwest and northeast regions.

关键词： climatic variables pressure system surface air temperature rainfall relative humidity Saudi Arabia

Recoil polarimetry in meson photoproduction at MAMi

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Chinese Physics C 2009年第12期33卷 1373-1376页

作者： M.H. Sikora d.i. Glazier d.P. Watts University of Edinburgh King’s Buildings Edinburgh EH9 3JZ United Kingdom

The nucleon excitation spectrum remains poorly known, with the masses, widths, EM couplings and even existence of many states not well established. A program of experiments using meson photoproduction off the nucleon is being carried out to improve this situation. A new large acceptance recoil polarimeter has been developed by the Edinburgh group for use in such reactions with the Crystal Ball at MAMi. This work summarizes the procedure used to measure recoil polarization with the new device and presents some preliminary results for the double polarization observable Cx in the reaction γp→pπ, compared to the current partial wave analysis.

关键词： polarimeter meson photoproduction polarization observable recoil

Effect of synthesis conditions and surrounding medium on luminescence properties of YVO_4:Eu^(3+) nanopowders

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Journal of Rare Earths 2015年第2期33卷 129-134页

作者： E.V.Golyeva d.V.Tolstikova i.E.Kolesnikov M.d.Mikhailov St.Petersburg State Polytechnical University St.Petersburg 195251 Russia Scientific and Technological institute of Optical Material Science VNTs S.I.Vavilov State Optical InstituteSt.Petersburg 192171 Russia St.Petersburg State University St.Petersburg 199034 Russia

Nanocrystalline yttrium vanadate doped with europium ions powders were synthesized via sol-gel method based on decomposition of metal-polymer complex. X-ray diffraction analysis showed that samples had pure tetragonal phase without any impurities. Scanning electron microscopy and static light scattering technique were used to study morphology and size of prepared nanoparticles. Average diameter of the nanoparticles was about 40 nm. The changes in structural and luminescence properties were observed as a function of the first and second calcination temperature. The optimal conditions for synthesis of nanoparticles were determined as Т1=500℃, t1=1 h; Т2=950 ℃, t2=1.5 h. The effect of different media surrounding the nanoparticles on their luminescence properties and lifetime was investigated and discussed in terms of effective refractive index. it was found that the observed lifetime of YVO4：Eu^3＋ 5 at.% nanophosphor was decreased from 0.64 ms in air（nmed=1） to 0.45 ms in chalcogenide glass As39S61（nmed=2.39）.

关键词： nanopowders rare earths luminescence effective refractive index lifetime

Marble epistyles under shear: an experimental study of the role of “Relieving Space”

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Frontiers of Structural and Civil Engineering 2019年第4期13卷 767-786页

作者： E. d. PASiOU i. STAVRAKAS d. TRiANTiS S. K. KOURKOULiS department of Mechanics Laboratory of Testing and Materials National Technical University of Athens Athens 15773 Greece department of Electronics Laboratory of Electrical Characterization of Materials and Electronic Devices Technological Edu-cational Institution of Athens Athens 12210 Greece

The mechanical response of mutually interconnected epistyles is studied experimentally. The specimens are made of two marble blocks connected to each other with an “i”-shaped titanium connector placed in grooves sculptured on the blocks and covered with cementitious material. The specific way of connecting epistyles simulates the one used by scientists restoring the ancient “connections” of the epistyles of the Parthenon Temple. This “connection”, although designed to sustain mainly tensile loading, undertakes, also, shear load, in case of excitations imposing to the epistyles displacements normal to the connector’s axis. Attention is focused to enlighten the role of a novel design technique aiming to relieve the stress field around the connector. According to this technique, part of the connector’s web is left uncovered, forming the so-called “Relieving Space”, assisting the unconstrained deformation of the connector. Both traditional and innovative sensing techniques were employed in an effort to obtain data from the interior of the three-material-complex (marble-cementitious material-titanium). Analysis of the data indicated that the “Relieving Space” reduces the overall stiffness of the system, protecting marble in case of over-loading. Moreover, it was concluded that the innovative techniques employed provide pre-failure indicators well in advance of the catastrophic failure of the specimens.

关键词： monuments of cultural heritage marble epistyles pressure stimulated currents acoustic emission digital image correlation