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نتایج جستجو برای Surface effect

تعداد نتایج: 1244029  
2011
G. B. Nam, J. W. Kim, J. M. Byeon, B. S. Kim, T. K. Kim, J. I. Song,

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2006
Min Hua Zhu, Giovanni Carbone, Charles Rosenblatt,

A polyimide coated substrate is treated so that vertical liquid crystal alignment (theta=0) obtains over the temperature range T(NA)< T < T(a), where T(NA) is the nematic-smectic-A transition temperature. When the cell is filled with a chiral liquid crystal whose helical pitch is unwound (surface stabilized), application of an in-plane electric field for T(NA)< T < T(a) induces a nonzero polar ...

Journal: :Physical review letters 2002
Kari Enqvist, Shinta Kasuya, Anupam Mazumdar,

We describe a new mechanism for reheating the Universe through evaporation of a surface charge of a fragmented inflaton condensate. We show that for a range of Yukawa coupling of the inflaton to the matter sector evaporation gives rise to a much smaller reheat temperature compared to the standard perturbative decay. As a consequence, reheating through a surface effect could solve the gravitino ...

1998
A. Novokhatski, M. Timm, T. Weiland,

In the Linear Colliders FEL projects ultra short bunches are foreseen to be used. In addition to usual wakefields, coming from irregularities in the chamber, these bunches excite fields in transporting lines and undulators due to the surface roughness. This effect can be large for the extruded tubes, usually used in accelerators. Based on computer results it is shown, that the roughness wakefie...

Journal: :Journal of applied physiology 2002
James P Butler, Richard E Brown, Dimitrije Stamenović, John P Morris, George P Topulos,

At fixed lung volume (VL), alterations in surface tension change alveolar surface area (S) and lung recoil (PL). Wilson (26), using data from fixed lungs (1, 9), quantified the isovolume change in S with PL. We reexamined this question in fresh excised rabbit lungs, with two important differences. First, we measured fractional changes in S by using diffuse light scattering, avoiding the potenti...

2016
Seyda Ersahan, Fidan Alakus Sabuncuoglu,

PURPOSE To compare the effects of different methods of surface treatment on enamel roughness. MATERIALS AND METHODS Ninety human maxillary first premolars were randomly divided into three groups (n=30) according to type of enamel surface treatment: I, acid etching; II, Er:YAG laser; III, Nd:YAG laser. The surface roughness of enamel was measured with a noncontact optical profilometer. For eac...

Behnam Gheshlaghi, Jafar Eskandari Jam, Yaser Mirzaei,

In this work,The free nonlinear vibrations of nanotubes using the Euler-Bernoulli beam theory along with the von Kármán geometric nonlinearity in presence of surface effects has been investigated. Natural frequencies of a simply-supported nanotube in terms of the Jacobi elliptic functions are obtained by using the free vibration modes of the corresponding linear problem. The numerical results d...

M. H. Noroozi Moghaddam, O. Rahmani,

Piezoelectric nanobeams having circular, rectangular and hexagonal cross-sections are synthesized and used in various Nano structures; however, piezoelectric nanobeams with hexagonal cross-sections have not been studied in detail. In particular, the physical mechanisms of the surface effect and the role of surface stress, surface elasticity and surface piezoelectricity have not been discussed t...

Hossein Entezari Zarch, Kazem Barkhordari,

During wars and crises, the underground tunnels are used as a safe space. Therefore, the stability and safety of them under a blast is of particular importance. In this paper, the Finite Difference Method has been used to study the influence of the change in geotechnical parameters and depth on surface blasting on subway tunnels. Results showed that increasing the internal friction angle, modul...

H Charsetad, S.M Khorsandijou,

The influence of surface roughness magnitude and direction on dry static friction coefficient between two similar steel samples has been studied through an experiment. A testing apparatus has been designed and fabricated to measure the friction coefficient for a few forms of surface asperity. According to the results of the experiments, dry friction coefficient is affected by both magnitude and...