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Interaction of a Two-Level Atom with the Morse Potential in the Framework of Jaynes-Cummings Model

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Chinese Physics Letters 2009年第9期26卷 169-172页

作者： M. R. Setare sh. Barzanjeh Department of Science Payame Noor University Bijar Iran Department of Physics Faculty of Science University of Isfahan Hezar Jerib Isfahan Iran

A theoretical study of the dynamical behaviors of the interaction between a two-level atom with a Morse potential in the framework of the Jaynes Cummings model （JCM） is discussed. We show that this system is equivalent to an intensity-dependent coupling between the two-level atom and the non-deformed single-mode radiation field in the presence of an additional nonlinear interaction. We study the dynamical properties of the system such as, atomic population inversion, the probability distribution of cavity-field, the Mandel parameter and atomic dipole squeezing. It is shown how the depth of the Morse potential can be affected by non-classical properties of the system. Moreover, the temporal evolution of the Husimi-distribution function is explored.

关键词： No English Keyword

High Preformation SiC-AlN Composites

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Journal of Materials Science & Technology 1997年第4期13卷 342-344页

作者： Chen, ZM Tan, sh Zhang, ZQ Jiang, DL shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China

High performance SiC-AlN composites were fabricated by hot-pressing with Y2O3 as additive via liquid phase sintering. The SiC-AlN composites containing 5 vol. pet AIN exhibit superior mechanical properties with flexural strength, fracture toughness and Vickers hardness of 1131 MPa, 6.1 MPa.m(1/2) and 28.6 GPa respectively. Microstructure observations indicate that the grain size of the composites is obviously inhibited due to the formation of solid solution. TEM-EDS analysis demonstrates the existence of the solid solution. In addition, subgrain boundaries induced by dislocations in the matrix SiC grains, seem to divide a large grain into numerous nano-sized small grains, which significantly increase the mechanical properties of the composites.

关键词： Ceramic matrix composites

Sliding Wear Behavior of a Grey Cast Iron Surface Remelted by TIG

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Journal of Materials Science & Technology 2009年第5期25卷 622-628页

作者： H.Mohamadzadeh H.Saghafian sh.Kheirandish Department of Metallurgy and Materials Engineering Iran University of Science and TechnologyTehranIran

The sliding wear behavior of a grey cast iron surface remelted by tungsten inert gas （TIG） was studied and compared with the unremelted one in the current work. To evaluate the wear behavior a Pin-on-Disk wear test machine was used. Pins which were prepared from the samples with the remelted layers of different thicknesses of 1.2, 1.8, 2.5 and 3 turn were worn on an AISID3 steel counterface having a hardness of 63HRC under the applied loads of 54, 76 and gg N at a constant sliding velocity of 0.45 m/s. Scanning electron microscopy （SEM） equipped with energy dispersive X-ray analysis （EDS） and X-ray diffraction （XRD） techniques were used to characterize worn surface and subsurface and also wear debris obtained from the wear tests under different test conditions. Results showed that surface remelted grey cast iron have better wear properties for all applied normal loads in comparison with unremelted ones. Microscopic studies on the worn surfaces and subsurfaces of samples revealed that dominant wear mechanism for surface remelted samples was mild oxidative, while it was severe for unremelted samples. Increasing remelted layer thickness and then forming grosser microstructure lead to a decline of wear properties, whereas lower thickness of remelted layer with finer microstructure due to having higher cooling rate through remelting process can withstand better against wear.

关键词： Grey cast Iron Surface remelted Tungsten inert gas (TIG) Wear

Synthesis and Characterization of Nanocrystalline Ni-Ti and Ni-Cr Powders by Mechanical Alloying

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Journal of Materials Science & Technology 1997年第2期13卷 86-90页

作者： Chen, SQ Zhou, YC Li, YY He, sh CHINESE ACAD SCI BEIJING 100864PEOPLES R CHINA

Nanocrystalline powders in the Ni-Ti and Ni-Cr systems were prepared by mechanical alloying (MA) of elemental crystalline powders in an inert atmosphere. The microstructure of the mechanically alloyed powders were characterized by XRD and TEM. The ball-milling process results in a drastic decrease of the crystallite size to the nanometer scale. X-ray diffraction analysis reveals that in the Ni-Cr system, no diffraction peaks from NiCr compound were observed even after 20 h of bail milling; while the lattice parameter of Ni increased with the milling time. In the Ni-Ti system, amorphous alloy was formed. Crystalline intermetallic compounds were obtained by post heat treatment of the amorphous alloy. The crystallization temperature of the amorphous NiTi alloy was obtained by DSC measurement.

关键词： Nanostructured materials

On Fuzzy Preordered Structures and (Fuzzy) Hyperstructures

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Acta Mathematica Sinica,English Series 2012年第9期28卷 1787-1798页

作者： Irina CRISTEA Morteza JAFARPOUR Seyed sh. MOUSAVI School of Applied Sciences University of Nova Gorica Department of Civil Engineering and Architecture University of Udine Mathematics Department Vali-e-Asr University of Rafsanjan Mathematics Department Shahid Bahonar University of Kerman

This article presents a connection between fuzzy preordered structures and hyperstructures. Firstly, we introduce the notion of fuzzy preordered semigroup and then, we construct a semihypergroup associated with it, giving some properties of the associated hyperstructure. Secondly, we define the notion of fuzzy preordered ring in order to construct a fuzzy hyperring.

关键词： Fuzzy preordered semigroup hypergroup fuzzy hyperring mutually associativity

Comparative studies on Y(Ⅲ)and Dy(Ⅲ)extraction from hydrochloric and nitric acids by Cyanex 572 as a novel extractant

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Journal of Rare Earths 2018年第12期36卷 1342-1350页

作者： N.E.El-Hefny M.S.Gasser sh.sh.Emam W.H.Mahmoud H.F.Aly Hot Laboratories Centre Atomic Energy Authority Faculty of Science Ain Shams University

Extraction of Y(III) and Dy(III) from hydrochloric and nitric acids by Cy-572 in kerosene was studied. The factors affecting the extraction were separately investigated. The stoichiometry of the extracted species was deduced on the basis of slope analysis method. Evaluation of extraction equilibrium and stripping investigation was studied as well as saponification effect of Cy-572. The composition of the extracted metal species in the organic phase was found to be [MA·(HA)] for Y(III) or Dy(III) in both media.1.0 mol/L HCI is the best stripping agent for each metal ion from the studied acidic media in one *** Cy-572 does not exhibit any selectivity towards the extraction of Y(III) or Dy(III) from both HCI and HNOsolutions. Based on the obtained results, the data were compared and the separation feasibility between lanthanides and Y(III) in the two media was discussed.

关键词： Extraction Cyanex-572 Yttrium Lanthanides Separation factor Saponification

The Alexandria retinopathy of prematurity model(Alex-ROP): postnatal weight gain screening algorithm application in a developing country

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International Journal of Ophthalmology(English edition) 2019年第2期12卷 296-301页

作者： Islam sh Ahmed Adham AO Badeeb Department of Ophthalmology Faculty of MedicineAlexandria Main University Hospital Department of Pediatrics and Neonatology Faculty of Medicine Alexandria University maternity Hospital

AIM: To suggest a novel retinopathy of prematurity(ROP) screening model in developing countries incorporating postnatal weight gain ratios(PWGR) to traditional parameters to maintain sensitivity and improve specificity in detecting ROP. METHODS: Analysis of weekly PWGR of infants from one tertiary referral center during six months to determine the age at which the PWGR with the highest predictability for ROP development which was referred to as the postnatal net weight gain ratio(NWGR). NWGR was added to conventional criteria to describe a new model(The Alex-ROP model). RESULTS: Of 560 infants were included. NWGR 28 d after birth was the most predictive factor for the development of ROP. A new model Alex-ROP recommending screening infants with gestational age(GA) ≤33 wk or birth weight ≤1500 g and NWGR at 28 d after birth <0.3 was suggested. A second screening model referred to as High-grade AlexROP(Hg Alex-ROP) model to detect worse grade ROP(Both type 1 and type 2) recommending a cutoff point of NWGR <0.15 between birth and 28^(th) day. CONCLUSION: Both Alex-ROP and Hg Alex-ROP models are easy to apply to improve the specificity of ROP screening in developing countries while maintaining high sensitivity.

关键词： screening retinopathy of prematurity postnatal weight gain

Scale dependence of tensile strength of micromachined polysilicon MEMS structures due to microstructural and dimensional constraints

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Chinese Science Bulletin 2001年第16期46卷 1392-1397页

作者： Ding, JN Meng, YG Wen, sh Tsing Hua Univ Natl Tribol Lab Beijing 100084 Peoples R China

The success of microelectromechanical systems (MEMS) as a key technology in the 21st century depends in no small part on the solution of materials issues associated with the design and fabrication of complex MEMS devices. The reliable mechanical properties of these thin films are critical to the safety and functioning of these microdevices and should be accurately determined. In order to accomplish a reliable mechanical design of MEMS, a new microtensile test device using a magnetic-solenoid force actuator was developed to evaluate the mechanical properties of microfabricated polysilicon thin films with dimensions of 100—660 mm length, 20—200 mm width, and 2.4 mm thickness. It was found that the measured average value of Young抯 modulus, 164±1.2 GPa, falls within the theoretical bounds. The average fracture strength is 1.36 GPa with a standarddeviation of 0.14 GPa, and the Weibull modulus is 10.4—11.7, respectively. Statistical analysis of the specimen size effect on the tensile strength predicated the size effect on the length, the surface area and the volume of the specimens due tomicrostructural and dimensional constraints. The fracturestrength increases with the increase of the ratio of surfacearea to volume. In such cases the size effect can be tracedback to the ratio of surface area to volume as the governing parameter. The test data account for the uncertainties inmechanical properties and may be used in the future reliability design of polysilicon MEMS. The testing of 40specimens to failure results in a recommendation for design that the nominal strain be maintained below 0.0057.

关键词： microelectromechanical systems polysilicon elasticmodulus tensile strength size effect.

PROXIMINAL SUBSPACES OF 2-NORMED SPACES

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Analysis in Theory and Applications 2006年第2期22卷 114-119页

作者： sh.Rezapour Azarbaidjan University of Tarbiat Moallem Iran

In 1965 Gohler introduced 2-normed spaces and since then, this topic have been intensively studied and developed. We shall introduce the notion of 1-type proximinal subspaces of 2-normed spaces and give some results i... 详细信息

关键词： b-proximinal subspaces 1-type proximinal subspaces 2-functionals