China
Africa
Explore chapters and articles related to this topic
Sparse Sampling in Microscopy
Published in Jeffrey P. Simmons, Lawrence F. Drummy, Charles A. Bouman, Marc De Graef, Statistical Methods for Materials Science, 2019
Kurt Larson, Hyrum Anderson, Jason Wheeler
In the microcircuit fabrication domain, parallel imaging can be implemented in a footprint the size of the wafer, so widely separated scanning systems can be built which simplifies parallel imaging. In biology and materials science, with unique small samples, the parallel imaging must be achieved in a much smaller area. Development of electron microscopes that can image in parallel in a small area is difficult. In response to an incident beam, electrons scatter from the sample by elastic and inelastic processes with a broad range of energies. The broad range of electron energies creates challenging conditions for imaging electron optics. For this reason, standard scanning electron microscopes use a simple potential field in the chamber to attract low-energy, inelastically-scattered (secondary) electrons to a single detector, one pixel at a time. If used for multiple illumination beams, this detection paradigm mixes the electrons emitted from the multiple incident beams. Wide-field or parallel imaging optics utilizing complex lens assemblies have been devised for specialized applications as in LEEM [68, 1008]. The Zeiss MultiSEM uses innovative illumination and imaging optics to scan many single-beam SEM images in parallel at landing energies less than 3 keV [484, 286]. Due to the complexity of their imaging optics, the LEEM and MultiSEM have significant constraints on electron landing energy which makes these systems specialized rather than general-purpose.
Cathode Ray Tube Displays
Published in John G. Webster, Halit Eren, Measurement, Instrumentation, and Sensors Handbook, 2017
Beam focusing and beam current are critical in determining the final spot size and thus the resolution of the CRT. Focusing a beam of electrons is directly analogous to focusing a beam of light; the discipline is called electron optics. Concerns familiar to optical imaging such as magnification, spherical aberration, and astigmatism also confront electron optics. As CRTs become larger, and operate at higher deflection angles, spot control becomes critical. Beam focusing is achieved using either electrostatic focusing grids or electromagnetic focusing coils. Electrostatic focus is the most extensively used technique. It can be found in use in applications from television to desktop computer monitors. Electrostatic focus is achieved by applying a succession of potentials across a complex sequence of focusing grids built into the electron gun. As designers seek to improve performance further, grid designs have become intricate [11,12]. Magnetic focus is the system of choice for all high-performance systems where resolution and brightness are design objectives. Magnetic lenses are better at producing a small spot with few aberrations. External coils in a yoke around the neck of the tube control the beam. Since it provides superior performance, electromagnetic focus is common on high-resolution commercial systems. Magnetic focus can also be achieved using permanent magnets and specialized hybrid electrostatic/magnetic focus components. Due to the tremendous impact focus has on resolution, tube suppliers continue to improve focus control [13,14]. For an excellent and comprehensive treatment of electron physics in CRTs, beam control, detailed design discussions, and other aspects of CRT devices, refer to Sol Sherr’s textbook [15].
Introduction
Published in Ramaswamy Jagannathan, Sameen Ahmed Khan, Quantum Mechanics of Charged Particle Beam Optics, 2019
Ramaswamy Jagannathan, Sameen Ahmed Khan
Any electron microscope is designed and operated using electron optics based entirely on classical mechanics. Quantum mechanics, or wave mechanics, is being used for understanding the image formation and resolution in electron microscopes since Glaser initiated the work in this direction (see Glaser [62] and references therein; see the encyclopedic three-volume text book of Hawkes and Kasper ([70, 71, 72]) for a comprehensive account of historical aspects and any technical aspect of geometrical electron optics and electron wave optics). In understanding the image formation in electron microscopy, mostly the nonrelativistic Schrödinger equation is used. In high-energy electron microscopy, one starts with the relativistic Klein-Gordon equation and soon approximates it to the nonrelativistic Schrödinger equation, often with a relativistic correction essentially based on replacing the rest mass m of the particle by the so-called relativistic mass γm=m/1-(v2/c2). It is considered that under the conditions obtained in high-energy electron microscopy, use of the Klein-Gordon equation, as approximation of the Dirac equation, is adequate (see, e.g., Ferwerda, Hoenders, and Slump [48, 49], Hawkes and Kasper [72], Groves [68], Lubk [129], and Pozzi [150]).
The synergistic action between anhydride grafted carbon fiber and intumescent flame retardant enhances flame retardancy and mechanical properties of polypropylene composites
Published in Science and Technology of Advanced Materials, 2018
Hai-ming Deng, Jia-you Xu, Xiu-yan Li, Yi-lan Ye, Hai-qing Chen, Si-yi Chen, Lei Miao, Hong Lin
Thermogravimetric analysis (TGA) was performed on a TGA400 thermo-analyzer instrument (PerkinElmer Inc., Fremont, CA, USA) from room temperature to 700 °C at a linear heating rate of 10 °C·min−1 under air and nitrogen (N2) atmospheres, respectively. Each sample was tested in an Al2O3 crucible with a weight about 5–8 mg. FTIR spectra were recorded with a VERTEX70 spectrometer (Bruker Instrument Co. Ltd., Dresden, Germany) with thin films of KBr at room temperature. The measurement was carried out in the optical range of 4000–500 cm−1. Raman measurements were performed with a LabRam HR Evolution Raman microscope (Horiba France Sas, Palaiseau, France), using an Ar+ ion laser with excitation wavelength of 514 nm. The morphology of CF, the char residues and its dispersion in PP were observed using a JSM-7001F scanning electron microscope (SEM; Japan Electron Optics Laboratory Co. Ltd., Tokyo, Japan). Dynamic mechanical analysis (DMA) was carried out with a DMA 2980 setup (TA Instruments, Newcastle, DE, USA) on samples with of 50 × 10 × 3 mm. The heating rate was 3 °C min−1 from −50 to 150 °C.
Box–Behnken design for the optimization of the removal of Cr(VI) in soil leachate using nZVI/Ni bimetallic particles
Published in Soil and Sediment Contamination: An International Journal, 2018
Siying He, Fang Zhu, Luwei Li, Wentao Ren
The morphology of nZVI/Ni particles was analyzed using JSM-6700F (Japan Electron Optics Laboratory Co., Ltd., Tokyo, Japan) field emission scanning electron microscope (SEM) at an operating voltage of 10.0 kV. X-ray photoelectron spectroscopy (XPS) analysis was obtained using AXIS ULTRA DLD X-ray photoelectron spectrometer (Kratos Co., Ltd., Manchester,England) with a monochromatic Al Kα radiation. Fourier transform infrared spectroscopy (FTIR) spectra was employed to identify the functional group of the materials over a wavenumber range from 400 to 4000 cm−1 using FTIR-8400S Fourier transform infrared spectrophotometer made by (SHIMADZU., Kyoto, Japan )X-ray diffraction (XRD) measurements were performed using an X-ray diffractometer (D/max 2500, Tokyo, Japan Rigaku) with a copper target tube radiation (Cu Kα). XRD spectra were acquired in a range of 20–90° consisting of 0.02° with a 2 s counting time at 40 kV and a tube current of 30 mA.
L-cysteine-based trimeric surfactants with hexahydro-1,3,5-triazine as the central core: Synthesis and self-assembly study
Published in Journal of Dispersion Science and Technology, 2018
Yaqin Liang, Hui Li, Jingxiang Shen, Shuping Zhang
Infrared spectra, using KBr pellets, were recorded using a Fourier transform infrared spectrometer (Model 8400S, Shimadzu Co., Japan). 1H nuclear magnetic resonance (NMR) spectra were recorded using a Bruker Avance nuclear magnetic resonance spectrometer (Model ARX-400, Bruker BioSpin Co., Switzerland) using tetramethylsilane (TMS) as the internal standard. Mass spectra were recorded using a Bruker Apex Fourier transform ion cyclotron resonance mass spectrometer (Model Apex IV, Bruker Co., America) using ESI as the ion source. The surface tensions of (CnCy)3Na3 and C12CyNa were determined using an automatic Wilhelmy plate tensiometer (Model K100, Krüss Co., Germany). The conductivity of the solutions for (CnCy)3Na3 and C12CyNa was determined using a low frequency conductometer (Model DDS-307, Shanghai Precision and Scientific Instrument Company, China). The diameter of the aggregates and the distribution measurements were carried out using a Zeta Plus particle size analyzer (Model BI-90Plus, Brookhaven Instrument Co., America). The morphology of the aggregates was obtained using a transmission electron microscope (Model JEM1011, Japan Electron Optics Laboratory Co., Japan) operated at an accelerating voltage of 80 kV.