نتایج جستجو برای: emission scanning

تعداد نتایج: 329633  

Journal: :Journal of nanoscience and nanotechnology 2010
Jianhui Dong Baoqing Zeng Yucheng Lan Shikai Tian Yun Shan Xingchong Liu Zhonghai Yang Hui Wang Z F Ren

Graphene nanosheets have been synthesized from commercial expandable graphite by heating in a microwave oven and dispersing in ethanol by ultrasonication. Scanning and transmission electron microscopy and electron energy-loss spectroscopy and atomic force microscope showed that the nanosheets were about 2 nm in thickness and 10 microm in diameter. The field emission of the graphene sheets has b...

2005
Hsiu-Fung Cheng Yen-Chih Lee Su-Jien Lin Tom T. Chen I-Nan Lin

The electron field emission properties of the nanodiamond films were examined using scanning tunneling microscopic sSTMd technique. Current image tunneling spectroscopic measurements reveal the direct dependence of electron tunneling/field emission behavior of the films on the proportion of grain boundaries present. Local tunneling current-voltage sIt–Vd measurements show that incorporation of ...

Journal: :Optics express 2013
Shawn Divitt Palash Bharadwaj Lukas Novotny

Light emission from the junction of a scanning tunneling microscope (STM) is examined in the presence of 20 nm topographical features in thin gold films. These features significantly modify the emission rates of the junction. Contributions to this modification are discriminated by examining emission rates on samples where the material is varied spatially. It is found that the variability in STM...

This paper is an attempt to synthesize nanostructured tantalum films on medical grade AISI 316L stainless steel (SS) using pulsed DC plasma assisted chemical vapor deposition (PACVD). The impact of duty cycle (17-33%) and total pressure (3-10 torr) were studied using field emission scanning electron microscopy (FESEM), grazing incidence x-ray diffraction (GIXRD), nuclear reaction analysis (NRA)...

Journal: :international journal of bio-inorganic hybrid nanomaterials 0

zno thin films were deposited on si(400) substrates by e-beam evaporation technique, and then post-annealed at different annealing temperatures (200-800°c). dependence of the crystallographic structure, nano-strain, chemical composition and surface physical morphology of these layers on annealing temperature were studied. the crystallographic structure of films was studied using x-ray diffracti...

ZnO thin films were deposited on Si(400) substrates by e-beam evaporation technique, and then post-annealed at different annealing temperatures (200-800°C). Dependence of the crystallographic structure, nano-strain, chemical composition and surface physical Morphology of these layers on annealing temperature were studied. The crystallographic structure of films was studied using X-Ray Diffracti...

Journal: :Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism 1990
K J Friston C D Frith P F Liddle R J Dolan A A Lammertsma R S Frackowiak

In order to localize cerebral cognitive or sensorimotor function, activation paradigms are being used in conjunction with PET measures of cerebral activity (e.g., rCBF). The changes in local cerebral activity have two components: a global, region independent change and a local or regional change. As the first step in localizing the regional effects of an activation, global variance must be remo...

Journal: :Nanotechnology 2008
Young Chul Choi Ji Won Lee Su Kyung Lee Mun Seok Kang Chang Soo Lee Kyu Won Jung Ji Hong Lim Jong Woon Moon Myung Ick Hwang Il Hwan Kim Yun Hee Kim Byong Gon Lee Hyung Rae Seon Sang Jin Lee Jong Hwan Park Yong C Kim Hun Soo Kim

We report on the fabrication of a carbon nanotube field emission backlight unit (CNT-BLU) and its application for liquid crystal displays (LCD). The CNT-BLU was operated with locally controllable luminance and impulse-type scanning. The local luminance control, which is based on a very small block size of 1 cm(2), consisted of local dimming and local brightening. This resulted in the contrast r...

Journal: :Chest 2002
Naresh C Gupta John S Rogers Geoffrey M Graeber Jessica L Gregory Usman Waheed David Mullet Melany Atkins

STUDY OBJECTIVES The goals of this study were to determine the sensitivity, specificity, and predictive accuracy of F-18 fluorodeoxyglucose positron emission tomography (PET-FDG) imaging in detecting metastatic disease involvement of pleura and/or presence of malignant pleural effusion in patients with proven lung cancer. We wanted to compare efficacy of PET-FDG imaging to CT scanning in differ...

2004
J. P. Singh F. Tang T. Karabacak T.-M. Lu G.-C. Wang

Well-aligned b-phase W~100! nanorods having square-base pyramidal apexes were grown on oxidized Si~100! substrate using glancing angle deposition technique with substrate rotation. The field emission characteristics of nanorods were measured using scanning tunneling microscope ~STM! tip as an extraction anode. A highly confined emission current of about 23 mA was obtained at a low extraction vo...

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