نتایج جستجو برای: glass structure

تعداد نتایج: 1629630  

پایان نامه :دانشگاه تربیت معلم - تهران - دانشکده علوم 1393

in this thesis, structural, electronical, and optical properties of inverse pervskite(ca3pbo) in cubic phase have been investigated.the calculation have been done based on density functional theory and according to generalized gradiant approximate (gga) as correlating potential. in order to calculate the configurations, implementing in the wien2k code have been used from 2013 version. first of ...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2017
Samuel S Schoenholz Ekin D Cubuk Efthimios Kaxiras Andrea J Liu

The dynamical glass transition is typically taken to be the temperature at which a glassy liquid is no longer able to equilibrate on experimental timescales. Consequently, the physical properties of these systems just above or below the dynamical glass transition, such as viscosity, can change by many orders of magnitude over long periods of time following external perturbation. During this pro...

2013
Peng He Lei Li Jianfeng Yu L. James Lee Allen Y Yi

The severe adhesion between silicon and glass has limited its application as mold material in precision glass molding. In this paper, a novel coating approach to create non-stick silicon mold for glass molding was introduced by using carbide-bonded graphene, a two dimensional material with a patterned atomic structure. A graphene coated silicon mold was fabricated using a coating process develo...

2015
A. Lepicard T. Cardinal E. Fargin F. Adamietz V. Rodriguez K. Richardson M. Dussauze

The ability to control glass surface reactivity at different length enables key properties required for future “smart substrates”. Employing a thermal poling process on a specific borosilicate glass composition can yield a surface with tailored physical and chemical properties. This work shows that during poling, alkali contained in the glass matrix migrates from the anode to the cathode side o...

1999
X. Lu E. M. Arruda W. W. Schultz

Birefringence of oxide glass bers drawn from glass melts through an ori ce has been detected previously [1, 2]. This birefringence is a measure of anisotropy in glass structure that can in uence ber performance properties. Birefringence is produced during ber drawing as the ber is rapidly stretched in the viscoelastic glass transition range. The birefringence is \frozen" into the glass during r...

Journal: :Learning & memory 2004
Larry Cahill Melina Uncapher Lisa Kilpatrick Mike T Alkire Jessica Turner

The amygdala appears necessary for enhanced long-term memory associated with emotionally arousing events. Recent brain imaging investigations support this view and indicate a sex-related hemispheric lateralization exists in the amygdala relationship to memory for emotional material. This study confirms and further explores this finding. Healthy men and women underwent functional Magnetic Resona...

2017
G. Johari G. P. Johari

The magnitude of secondary relaxation and heat capacity of a variety of glasses decrease on physical ageing. The decrease suggests a collapse of localized high-volume, highentropy regions in its structure. Densification on ageing affects the kinetic, vibrational and electronic properties of a glass differently than does densification on compression. Tunneling centres responsible for the low-tem...

Journal: :Journal of biomedical materials research 1996
O Peitl Filho G P LaTorre L L Hench

The bioactive glass 45S5 was crystallized to 8-100 vol % of crystals by thermal treatments from 550-680 degrees C. The micro-structure of the glass-ceramics had a very uniform crystal size, ranging from 8 to 20 microns. Fourier-transform infrared (FTIR) spectroscopy was used to determine the rate of hydroxycarbonate apatite (HCA) formation that occurs on bioactive glass and glass-ceramic implan...

زرگرشوشتری, مرتضی, نادری, معصومه, کاظمی‌نژاد, ایرج,

In this research, ZnO nanorods were grown via hydrothermal method on the glass substrate. The effect of precursor and the thickness of the seed layer on the structural and optical properties of grown ZnO nanorods were investigated using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and UV-vis spectroscopy. The XRD patterns indicated that the nanorods had wrutzite ...

2004
Chandan Dasgupta Oriol T. Valls

We study the melting transition of the low-temperature vortex solid in strongly anisotropic layered superconductors with a concentration of random columnar pinning centers small enough so that the areal density of the pins is much less than that of the vortex lines. Both the external magnetic field and the columnar pins are assumed to be oriented perpendicular to the layers. Our method, involvi...

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