نتایج جستجو برای: focal spot size
تعداد نتایج: 644850 فیلتر نتایج به سال:
A microfocus x-ray tube that can generate x rays with the focal spot size less than 5 m has been demonstrated using carbon nanotube CNT field emitters. A CNT cathode on a sharp tungsten tip, a magnetic solenoid lens, and a transmission-type x-ray target were adopted for the microfocus x-ray tube. The design characteristics and the operation performance of the microfocus x-ray tube are presented...
Engineered microsphere possesses the advantage of strong light manipulation at sub-wavelength scale and emerges as a promising candidate to shrink the focal spot size. Here we demonstrated a center-covered engineered microsphere which can adjust the transverse component of the incident beam and achieve a sharp photonic nanojet. Modification of the beam width and working distance of the photonic...
OBJECTIVE Different angiographic protocols may influence the radiation dose and image quality. In this study, we aimed to investigate the effects of filtration and focal spot size on radiation dose and image quality for diagnostic cerebral angiography using an in-vitro model and in-vivo patient groups. MATERIALS AND METHODS Radiation dose and image quality were analyzed by varying the filtrat...
We present an approach to modelling the effect of the laser focal spot size on the acceleration of protons from ultra-thin foil targets irradiated by ultra-short laser pulses of intensity 1016–1018 W cm−2. An expression is introduced for the proton acceleration time, which takes account of the time taken for the laser-accelerated electrons, which expand laterally at the rear surface of the targ...
Background: Benign pigmented lesions, including freckles, are common and various treatment modalities including lasers and peeling have been evaluated for their effectiveness in their treatment.Objective: To compare the clinical effects of focal peeling with Trichloroacetic Acid (TCA) and Nd:YAG (532 nm) laser on freckles.Methods: Twenty patients with freckles were treated with foca...
The purpose of this study was to evaluate the use of digital x-ray imaging detectors for the measurement of diagnostic x-ray tube focal spot size using a slit camera. Slit camera images of two focal spots for a radiographic x-ray tube were acquired with direct-exposure film (DF) (as specified by the National Electrical Manufacturers Association [NEMA] Standards Publication No. XR 5, 1992), comp...
resistance spot welding is an important manufacturing process in the automotive industry for assembling bodies. the quality and strength of the welds and, by extension, the body is mainly defined by the quality of the weld nuggets. the most effective parameters in this process are sheet material, geometry of electrodes, electrode force, current intensity, welding time and sheet thickness. the p...
Thin Al foils (50 nm and 6μm) were irradiated at intensities of up to 2x1019Wcm−2 using high contrast (108) laser pulses. Ion emission from the rear of the targets was measured using a scintillator-based Thomson parabola and beam sampling ‘footprint’ monitor. The variation of the ion spectra and beam profile with focal spot size was systematically studied. The results show that while the maximu...
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