نتایج جستجو برای: beams

تعداد نتایج: 33005  

2018
Daisuke Kawahara Shuichi Ozawa Akito Saito Tomoki Kimura Tatsuhiko Suzuki Masato Tsuneda Sodai Tanaka Takeo Nakashima Yoshimi Ohno Yuji Murakami Yasushi Nagata

PURPOSE Lipiodol, which was used in transcatheter arterial chemoembolization before liver stereotactic body radiation therapy (SBRT), remains in SBRT. Previous we reported the dose enhancement in Lipiodol using 10 MV (10×) FFF beam. In this study, we compared the dose enhancement in Lipiodol and evaluated the probability of electron generation (PEG) for the dose enhancement using flattening fil...

Journal: :مهندسی عمران فردوسی 0
علی حاجی هاشمی داوود مستوفی نژاد مجتبی ازهری

the current study is focused on strengthening of reinforced concrete (rc) beams using cfrp straps installed in pre-cut grooves. the method which is referred as near surface mounted (nsm) benefits considerable advantages in comparison with the conventional externally bonded reinforcement (ebr) method and provides better normal and shear stress transfer between the frp and concrete substrate. the...

2013
Md. A. Alam M. Z. Jumaat

Strengthening of reinforced concrete beams using externally bonded CFRP laminate is the most popular choice. However, premature end peeling of CFRP laminate has been shown to be the main weakness of this method. Development of high shear and normal stresses at the end of strengthening laminate is the key reason to cause end peeling which is not preventable by conventional anchoring system. This...

2015
Marcelino Anguiano-Morales

In this letter, we explore the possibilities of generating diffraction-free caustics over a predetermined range. For the first time we demonstrate the possibility to generate diffraction-free caustic beams. Caustic beams are a topic of increased interest over the past few years. Diffraction-free caustics may find applications in situations where large depth of field and uniform axial energy dis...

Journal: :Optics express 2013
Marco Ornigotti Andrea Aiello

We present a method for the realization of radially and azimuthally polarized nonparaxial Bessel beams in a rigorous but simple manner. This result is achieved by using the concept of Hertz vector potential to generate exact vector solutions of Maxwell's equations from scalar Bessel beams. The scalar part of the Hertz potential is built by analogy with the paraxial case as a linear combination ...

2013
Khan Ahmed

It is observed that, reinforced concrete beams failed due to flexure but in case of deep beam failure occur due to shear. Deep beams may be defined as the beam where shear span to depth ratio less than 2. A number of researchers already proposed various approach to predict the ultimate strength of deep beams. In this study a newer approach is developed to calculate the ultimate shear strength o...

2017
Xiao J Zheng James C L Chow

AIM To investigated the dose enhancement due to the incorporation of nanoparticles in skin therapy using the kilovoltage (kV) photon and megavoltage (MV) electron beams. Monte Carlo simulations were used to predict the dose enhancement when different types and concentrations of nanoparticles were added to skin target layers of varying thickness. METHODS Clinical kV photon beams (105 and 220 k...

Journal: :Proceedings. Biological sciences 2011
Clelia Gasparini Andrea Pilastro

As inbreeding is costly, it has been suggested that polyandry may evolve as a means to reduce the negative fitness consequences of mating with genetically related males. While several studies provide support for this hypothesis, evidence of pure post-copulatory mechanisms capable of biasing paternity towards genetically unrelated males is still lacking; yet these are necessary to support inbree...

1968
V. Kollárová T. Medřík R. Čelechovský Z. Bouchal O. Wilfert Z. Kolka

In wireless optical communications, information is carried by coherent laser beams propagating through the free space. In realized communication channels, the standard beams created directly in the laser resonator are utilized. In recent time, an increasing attention has been focused on the so-called nondiffracting beams generated by auxiliary optical systems. In this paper, the theoretical and...

2009
B.-H. Sun S.-G. Zhou Y.-F. Wei Q.-Z. Liu

A modified two-element Yagi-Uda antenna with tunable beams in the H-plane (including four significant beams: forward, backward, omni-directional, and bi-directional beams) is presented. These tunable beams are achieved by simply adjusting the short-circuit position of the transmission line connected to the parasitic element. The principle of operation is investigated by examining the current re...

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