High-angle Kikuchi patterns

A cylindrical specimen chamber and camera have been used to study the high-angle Kikuchi patterns obtained by reflexion of electrons, of energy 6 to 50 keV, from the cleavage surfaces of crystals with the sodium chloride structure. Angles of scattering ranging from 0 to 164° were covered. The relative intensity of the pattern at different scattering angles was measured using a photographic technique. The intensity distribution was found to become less steep as the energy of the incident electrons decreased. In photographs taken with a large value of the glancing angle of incidence, defect bands were found, starting near the shadow edge of the pattern; these changed to excess bands at higher angles of scattering. The most striking feature of the results is the remarkable intensity and clarity at the highest scattering angles of the pattern produced by crystals such as lead sulphide and potassium iodide, the constituents of which have a relatively high elastic scattering cross-section. In marked contrast, a relatively low intensity and low clarity was found at these angles for lithium fluoride under the same experimental conditions. An investigation of the width of Kikuchi bands, visible over the whole available angular range, showed that the electrons forming these bands had the same energy as that of the incident electrons within the experimental error of 10%. A possible mechanism is discussed by means of which electrons can be diffused through large angles with high efficiency, relative to small angles, and with relatively little loss of energy.

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Atomic Imaging of Crystals using Large-Angle Electron Scattering in STEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100179129 ◽

1990 ◽

Vol 48 (1) ◽

pp. 74-75

Author(s):

D.E. Jesson ◽

S. J. Pennycook

Keyword(s):

Wave Function ◽

Electron Scattering ◽

Numerical Solutions ◽

Large Angle ◽

Real Space ◽

High Angle ◽

Analytical Treatment ◽

Order Zero ◽

Experimental Conditions ◽

Ewald Sphere

It is well known that conventional atomic resolution electron microscopy is a coherent imaging process best interpreted in reciprocal space using contrast transfer function theory. This is because the equivalent real space interpretation involving a convolution between the exit face wave function and the instrumental response is difficult to visualize. Furthermore, the crystal wave function is not simply related to the projected crystal potential, except under a very restrictive set of experimental conditions, making image simulation an essential part of image interpretation. In this paper we present a different conceptual approach to the atomic imaging of crystals based on incoherent imaging theory. Using a real-space analysis of electron scattering to a high-angle annular detector, it is shown how the STEM imaging process can be partitioned into components parallel and perpendicular to the relevant low index zone-axis.It has become customary to describe STEM imaging using the analytical treatment developed by Cowley. However, the convenient assumption of a phase object (which neglects the curvature of the Ewald sphere) fails rapidly for large scattering angles, even in very thin crystals. Thus, to avoid unpredictive numerical solutions, it would seem more appropriate to apply pseudo-kinematic theory to the treatment of the weak high angle signal. Diffraction to medium order zero-layer reflections is most important compared with thermal diffuse scattering in very thin crystals (<5nm). The electron wave function ψ(R,z) at a depth z and transverse coordinate R due to a phase aberrated surface probe function P(R-RO) located at RO is then well described by the channeling approximation;

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The light-oxygen effect in biological cells enhanced by highly localized surface plasmon-polaritons

Scientific Reports ◽

10.1038/s41598-019-54905-5 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 2

Author(s):

Anna Khokhlova ◽

Igor Zolotovskii ◽

Sergei Sokolovski ◽

Yury Saenko ◽

Edik Rafailov ◽

...

Keyword(s):

Surface Plasmon ◽

Localized Surface Plasmon ◽

Oxygen Effect ◽

Experimental Conditions ◽

Strong Laser Field ◽

Low Intensity ◽

Spectrum Band ◽

Plasmon Polariton ◽

Oxidative Effects ◽

Plasmon Polaritons

AbstractHere at the first time we suggested that the surface plasmon-polariton phenomenon which it is well described in metallic nanostructures could also be used for explanation of the unexpectedly strong oxidative effects of the low-intensity laser irradiation in living matters (cells, tissues, organism). We demonstrated that the narrow-band laser emitting at 1265 nm could generate significant amount of the reactive oxygen species (ROS) in both HCT116 and CHO-K1 cell cultures. Such cellular ROS effects could be explained through the generation of highly localized plasmon-polaritons on the surface of mitochondrial crista. Our experimental conditions, the low-intensity irradiation, the narrow spectrum band (<4 nm) of the laser and comparably small size bio-structures (~10 μm) were shown to be sufficient for the plasmon-polariton generation and strong laser field confinement enabling the oxidative stress observed.

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Algorithms for determining the phase of RHEED oscillations

Journal of Applied Crystallography ◽

10.1107/s1600576715020415 ◽

2015 ◽

Vol 48 (6) ◽

pp. 1927-1934 ◽

Cited By ~ 5

Author(s):

Zbigniew Mitura ◽

Sergei L. Dudarev

Keyword(s):

Experimental Data ◽

Direct Method ◽

Incident Beam ◽

Diffraction Theory ◽

High Energy ◽

Angle Of Incidence ◽

High Energy Electron ◽

Dynamical Diffraction ◽

Glancing Angle ◽

Low Symmetry

Oscillations of reflection high-energy electron diffraction (RHEED) intensities are computed using dynamical diffraction theory. The phase of the oscillations is determined using two different approaches. In the first, direct, approach, the phase is determined by identifying the time needed to reach the second oscillation minimum. In the second approach, the phase is found using harmonic analysis. The two approaches are tested by applying them to oscillations simulated using dynamical diffraction theory. The phase of RHEED oscillations observed experimentally is also analysed. Experimental data on the variation of the phase as a function of the glancing angle of incidence, derived using the direct method, are compared with the values computed using both the direct and harmonic methods. For incident-beam azimuths corresponding to low-symmetry directions, both approaches produce similar results.

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Transcranial focused ultrasound modulates cortical and thalamic motor activity in awake sheep

Scientific Reports ◽

10.1038/s41598-021-98920-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Hyun-Chul Kim ◽

Wonhye Lee ◽

Jennifer Kunes ◽

Kyungho Yoon ◽

Ji Eun Lee ◽

...

Keyword(s):

Focused Ultrasound ◽

Brain Activity ◽

Response Rates ◽

Behavioral Observation ◽

Acoustic Stimulation ◽

Motion Artifacts ◽

Experimental Conditions ◽

Low Intensity ◽

Hind Limbs ◽

Brain Tissue Damage

AbstractTranscranial application of pulsed low-intensity focused ultrasound (FUS) modulates the excitability of region-specific brain areas, and anesthetic confounders on brain activity warrant the evaluation of the technique in awake animals. We examined the neuromodulatory effects of FUS in unanesthetized sheep by developing a custom-fit headgear capable of reproducibly placing an acoustic focus on the unilateral motor cortex (M1) and corresponding thalamic area. The efferent responses to sonication, based on the acoustic parameters previously identified in anesthetized sheep, were measured using electromyography (EMG) from both hind limbs across three experimental conditions: on-target sonication, off-target sonication, and without sonication. Excitatory sonication yielded greater amplitude of EMG signals obtained from the hind limb contralateral to sonication than that from the ipsilateral limb. Spurious appearance of motion-related EMG signals limited the amount of analyzed data (~ 10% selection of acquired data) during excitatory sonication, and the averaged EMG response rates elicited by the M1 and thalamic stimulations were 7.5 ± 1.4% and 6.7 ± 1.5%, respectively. Suppressive sonication, while sheep walked on the treadmill, temporarily reduced the EMG amplitude from the limb contralateral to sonication. No significant change was found in the EMG amplitudes during the off-target sonication. Behavioral observation throughout the study and histological analysis showed no sign of brain tissue damage caused by the acoustic stimulation. Marginal response rates observed during excitatory sonication call for technical refinement to reduce motion artifacts during EMG acquisitions as well as acoustic aberration correction schemes to improve spatial accuracy of sonication. Yet, our results indicate that low-intensity FUS modulated the excitability of regional brain tissues reversibly and safely in awake sheep, supporting its potential in theragnostic applications.

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Research on Key Technology of Electrochemical Sterilization and Physical Application for Circulating Cooling Water

Journal of Physics Conference Series ◽

10.1088/1742-6596/2083/2/022068 ◽

2021 ◽

Vol 2083 (2) ◽

pp. 022068

Author(s):

Xiaohui Wang ◽

Chunyan Song ◽

Xueying Xie ◽

Nan Zhang ◽

Ruiqing Guo ◽

...

Keyword(s):

Electric Fields ◽

Electrode Materials ◽

High Efficiency ◽

Thermal Power ◽

Cooling Water ◽

Environmentally Friendly ◽

Research Progress ◽

Electrode Spacing ◽

Experimental Conditions ◽

Circulating Cooling Water

Abstract As a high-efficiency, low-cost, convenient and environmentally friendly sterilization technology, electrochemical disinfection has developed rapidly in recent years. Electrochemical sterilization is an environmentally friendly sterilization technology. The research progress of this technology in the recent 30 years in sterilization mechanism and electrode materials is summarized. The mechanism of electrochemical sterilization includes the chemical effects of active chlorine, active intermediates, copper or silver ions, and the physical effects of electric fields; the electrode materials used are titanium anode, carbon cathode, and anode. The article combined with electrochemical equipment in a thermal power plant cold open circulating cooling water treatment experiment. Experimental research found that under the conditions of current density of 120A/m2, residence time of 10s, and electrode spacing of 1.8cm, the bactericidal effect can reach 97%. Under certain experimental conditions and a certain period of time, the total number of heterogeneous bacteria in the circulating cooling water after treatment can be effectively inhibited.

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Laser therapy in patients operated for orthognathic pathology

Fizioterapevt (Physiotherapist) ◽

10.33920/med-14-2104-04 ◽

2021 ◽

pp. 32-37

Author(s):

Natalya Gennadievna Kulikova ◽

Z.G. Zhilokov ◽

A.S. Tkachenko

Keyword(s):

Laser Radiation ◽

Laser Therapy ◽

Postoperative Period ◽

High Efficiency ◽

Pulse Mode ◽

Early Postoperative Period ◽

Pulse Radiation ◽

Dental Patients ◽

Low Intensity ◽

Intensity Parameters

The study is carried out with an emphasis on modern aspects of the diagnosis and treatment of patients with orthognathic disorders in the dynamics of laser therapy of different wavelengths, frequency and intensity parameters, dosed in pulse mode. It has been noted that the consistent use of laser low-intensity pulse radiation (ƛ=635nm) and laser low-intensity pulse radiation (l’904nm) increases the effectiveness of rehabilitation of dental patients in the early postoperative period, which is confirmed by the regression of initial shifts of microhemoregulatory indicators. The article demonstrates the feasibility and high efficiency of the application of complex physiotherapy, including laser radiation after orthognathic operations.

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The Flapping Flight of Birds. II

Journal of the Royal Aeronautical Society ◽

10.1017/s036839310013768x ◽

1927 ◽

Vol 31 (196) ◽

pp. 337-342 ◽

Cited By ~ 10

Author(s):

Gilbert T. Walker

Keyword(s):

Mechanical Model ◽

High Efficiency ◽

Flapping Flight ◽

Angle Of Incidence ◽

Negative Work ◽

Outer Portion ◽

Pectoralis Minor ◽

Standard Section ◽

Large Muscle

In a paper in the number of this journal for November, 1925, it was shown that if a flying machine were fitted with wings of standard section and these were flapped in a rhythmical manner, the machine would be supported and propelled, its weight, dimensions and velocity being those of a typical bird; the degree of accuracy attempted in the analysis did not exceed five per cent.A subsequent examination of the power involved established a high efficiency; but this was due to a large amount of negative work during up–beats; and although such conditions might be maintained in a mechanical model they were unlikely in a bird, which has a large muscle, the pectoralis minor, for lifting its wings. In a bird efficiency seemed to require that the angle of incidence of the outer portion during an up–beat should be negative (see §7, p. 593, of the previous paper); the angle was however made zero (see §9) in order to secure adequate lift, and it is this feature which gives rise to the negative work.

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Lithium Fluoride Based Electron Contacts for High Efficiency n-Type Crystalline Silicon Solar Cells

Advanced Energy Materials ◽

10.1002/aenm.201600241 ◽

2016 ◽

Vol 6 (14) ◽

pp. 1600241 ◽

Cited By ~ 66

Author(s):

James Bullock ◽

Peiting Zheng ◽

Quentin Jeangros ◽

Mahmut Tosun ◽

Mark Hettick ◽

...

Keyword(s):

Solar Cells ◽

Lithium Fluoride ◽

High Efficiency ◽

Crystalline Silicon ◽

Silicon Solar Cells ◽

Crystalline Silicon Solar Cells

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Design and Implementation of an Intensified Coprecipitation Reactor for the Treatment of Liquid Radioactive Wastes

Volume 1: Low/Intermediate-Level Radioactive Waste Management; Spent Fuel, Fissile Material, Transuranic and High-Level Radioactive Waste Management ◽

10.1115/icem2013-96033 ◽

2013 ◽

Author(s):

Julie Flouret ◽

Yves Barré ◽

Hervé Muhr ◽

Edouard Plasari

Keyword(s):

Reaction Zone ◽

Residence Time ◽

Flow Rate ◽

High Efficiency ◽

Solid Phase ◽

Continuous Process ◽

Decontamination Factor ◽

Barium Nitrate ◽

Molar Ratio ◽

Experimental Conditions

The coprecipitation is a robust and inexpensive process for the treatment of important volumes of low and intermediate radioactive level liquid wastes. Its major inconvenient is the huge volume of sludge generated. The purpose of this work is to optimize the industrial coprecipitation continuous process by achieving the following objectives: - maximize the decontamination efficiency; - minimize the volume of sludge generated by the process; - reduce the treatment cost decreasing the installation volume. An innovative reactor with an infinite recycling ratio was therefore designed. It is a multifunctional reactor composed of two zones: a perfectly mixed precipitation zone and a classifier to perform liquid-solid separation. The experiments are focused on the coprecipitation of strontium by barium sulphate. The effluent containing sulphate ions and the barium nitrate solution are injected in the reaction zone where strontium and barium coprecipitate as sulphates. The produced solid phase is returned into the reaction zone by the classifier and goes out slowly from the reactor bottom with a residence time much higher than the liquid phase. This creates both a high concentration of solid phase in the reaction zone and a high efficiency of decontamination. The experimental conditions simulate the industrial effluents. The total treatment flow rate is 17 L/h, with an effluent flow rate of 16 L/h and a reactive flow rate of 1 L/h, hence a mean residence time of 10 minutes. In these experimental conditions, the molar ratio sulphate/barium after mixing corresponds to 4.9. These conditions are used in the reprocessing plant of La Hague. The decontamination factor reached in these experimental conditions is excellent: DF = 1500. The decontamination factor obtained with the classical continuous process is only equal to 60. Different process parameters are studied in order to optimize the reactor/classifier: residence time, barium nitrate flow rate and racking flow rate. The decrease of barium nitrate flow rate reduces the volume of sludge generated by the process keeping a high efficiency of strontium decontamination: DF = 400. An excess of sulphate is necessary to perform an efficient decontamination, but the molar ratio sulphate/barium can be reduced to 3 instead of 4.9 used industrially. The reactor/classifier also represents an efficient device for the coprecipitation process intensification. Indeed, it can sensibly reduce the final installation size while treating important volume of effluents. This innovative reactor optimizes both the decontamination efficiency of radioactive liquid wastes and the reduction of sludge volume. A reduction of sulphate ions in the discharge is also possible, which is environmentally friendly.

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