The authors studied the photoemission from molybdenum nanotip arrays with controlled apex curvatures by photoelectron microscopy and spectroscopy excited by 10 ps visible laser pulses under dc electric field. While two-photon photoemission microscopy demonstrates the enhancement of photoabsorption at the sharp tip apex, spatially resolved analysis of the photoelectron energy revealed anomalous ...

introduction: objective: this study aimed to assess the possible variations in root canal anatomy and topography of the apices of first and second maxillary molars. materials and methods: a total of 67 first and second maxillary permanent molars were collected. access cavity was prepared and 2% methylene blue was injected. the teeth were demineralized by 5% nitric acid and cleared with methyl s...

Introduction: Knowledge of the internal anatomy of the tooth, apical foramen (AF) and mental foramen (MF) is considered a basic prerequisite before root canal surgical and non-surgical treatments. The aim this study is evaluation the distance and situation of AF & MF to anatomic apex of mandibular  premolar. Materials & Methods: In this cross-sectional study, CBCT images of mandibular p...

We demonstrate that the giant spin contrast observed by scanning tunneling microscopy for double-layer Coislands on Pt(111) is caused by adsorbates at the apex of the Cr-coated W tip. The most likely candidate, in ab initio simulations, is hydrogen. Here, the electron charge is highly polarized by the adjacent Cr layers. The hydrogen adsorption site is shown to change from hollow to on top due ...

PURPOSE The tip-apex distance (TAD) is used to predict the clinical outcome of intertrochanteric fracture fixation. We aimed to measure the changes in TAD by position and film distance using Picture Archiving and Communication System (PACS). MATERIALS AND METHODS We used a femur replica with a 10° femoral neck anteversion and a 130° neck shaft angle. Proximal femoral nail antirotation nail an...

In the present work, characterization of the surface trenches and vacancies with Amplitude Modulation AFM (AM-AFM) using Molecular Dynamics (MD) is simulated and the e ects of the tip shape on the resulting images are investigated. The simulated system includes a recently developed gold coated AFM probe which interacts with a sample including a surface trench or a single-atom vacancy. In order ...

We have developed a simple, reliable and reproducible method for preparing single-atom tips. With electrochemical techniques, a very small amount of a noble metal is plated on the surface of a clean Wh111i tip. Upon annealing the tip at an appropriate temperature in vacuum, a three-sided {211} pyramid with a single-atom sharpness is formed spontaneously at the tip apex by adsorbate-induced face...

Near the cut-off radius of a guided waveguide mode of a metal-coated glass fibre tip it is possible to couple radiation to surface plasmons propagating on the outside surface of the metal coating. These surface plasmons converge toward the apex of the tip and interfere constructively for particular polarization states of the initial waveguide mode. Calculations show that a radially polarized wa...

We present ab initio simulations of AFM image formation in the non-contact regime for prototypical reactive semiconductor and metal surfaces: InP(1 1 0)-1 1 and Cu(0 0 1). For the reactive surface the effect of tip morphology of the tip apex was also studied. The nature of the tip apex alters the local tip reactivity and can lead to reversal of the apparent AFM surface corrugation. We find that...