scholarly journals Dynamical visualization of anisotropic electromagnetic re-emissions from a single metal micro-helix at THz frequencies

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
T. Notake ◽  
T. Iyoda ◽  
T. Arikawa ◽  
K. Tanaka ◽  
C. Otani ◽  
...  
Keyword(s):  
Real Time ◽  
Electromagnetic Waves ◽  
Electromagnetic Compatibility ◽  
Smart Antenna ◽  
Dynamical Behavior ◽  
Measurement Techniques ◽  
Spatial Evolution ◽  
Frequency Spectra ◽  
3D Objects ◽  
Current Oscillations

AbstractThe capability for actual measurements—not just simulations—of the dynamical behavior of THz electromagnetic waves, including interactions with prevalent 3D objects, has become increasingly important not only for developments of various THz devices, but also for reliable evaluation of electromagnetic compatibility. We have obtained real-time visualizations of the spatial evolution of THz electromagnetic waves interacting with a single metal micro-helix. After the micro-helix is stimulated by a broadband pico-second pulse of THz electromagnetic waves, two types of anisotropic re-emissions can occur following overall inductive current oscillations in the micro-helix. They propagate in orthogonally crossed directions with different THz frequency spectra. This unique radiative feature can be very useful for the development of a smart antenna with broadband multiplexing/demultiplexing ability and directional adaptivity. In this way, we have demonstrated that our advanced measurement techniques can lead to the development of novel functional THz devices.

scholarly journals Programmable Reflection–Transmission Shared‐Aperture Metasurface for Real‐Time Control of Electromagnetic Waves in Full Space

2021 ◽  
pp. 2100149
Author(s):  
Lei Bao ◽  
Qian Ma ◽  
Rui Yuan Wu ◽  
Xiaojian Fu ◽  
Junwei Wu ◽  
...  
Keyword(s):  
Real Time ◽  
Electromagnetic Waves ◽  
Real Time Control ◽  
Time Control

Three-dimensional Force Perception of Robotic Bipolar Forceps for Brain Tumor Resection

2021 ◽  
Author(s):  
Xiu-Heng Zhang ◽  
Heng Zhang ◽  
Zhen Li ◽  
Gui-Bin Bian
Keyword(s):  
Brain Tumor ◽  
Real Time ◽  
Force Measurement ◽  
Measurement Techniques ◽  
Tumor Resection ◽  
Three Dimensional ◽  
Contact Forces ◽  
Surgical Instruments ◽  
Force Perception ◽  
Brain Tumor Resection

Abstract Three-dimensional force perception is critically important in the enhancement of human force perception to minimize brain injuries resulting from excessive forces applied by surgical instruments in robot-assisted brain tumor resection. And surgeons are not responsive enough to interpret tool-tissue interaction forces. In previous studies, various force measurement techniques have been published. In neurosurgical scenarios, there are still some drawbacks to these presented approaches to forces perception. Because of the narrow, and slim configuration of bipolar forceps, three-dimensional contact forces on forceps tips is not easy to be traced in real-time. Five fundamental acts of handling bipolar forceps are poking, opposing, pressing, opening, and closing. The first three acts independently correspond to the axial force of z, x, y. So, in this paper, typical interactions between bipolar forceps and brain tissues have been analyzed. A three-dimensional force perception technique to collect force data on bipolar forceps tips by installing three Fiber Bragg Grating Sensors (FBGs) on each prong of bipolar forceps in real-time is proposed. Experiments using a tele-neurosurgical robot were performed on an in-vitro pig brain. In the experiments, three-dimensional forces were tracked in real-time. It is possible to experience forces at a minimum of 0.01 N. The three-dimensional force perception range is 0-4 N. The calibrating resolution on x, y, and z, is 0.01, 0.03, 0.1 N, separately. According to our observation, the measurement accuracy precision is over 95%.

Geologic Modelling Using Augmented Reality

2021 ◽  
Author(s):  
Phathompat Boonyasaknanon ◽  
Raymond Pols ◽  
Katja Schulze ◽  
Robert Rundle
Keyword(s):  
Augmented Reality ◽  
Real Time ◽  
3D Models ◽  
New Approach ◽  
Domain Experts ◽  
3D Objects ◽  
Track Record ◽  
Initial Work ◽  
Geologic Model ◽  
Time Critical

Abstract An augmented reality (AR) system is presented which enhances the real-time collaboration of domain experts involved in the geologic modeling of complex reservoirs. An evaluation of traditional techniques is compared with this new approach. The objective of geologic modeling is to describe the subsurface as accurately and in as much detail as possible given the available data. This is necessarily an iterative process since as new wells are drilled more data becomes available which either validates current assumptions or forces a re-evaluation of the model. As the speed of reservoir development increases there is a need for expeditious updates of the subsurface model as working with an outdated model can lead to costly mistakes. Common practice is for a geologist to maintain the geologic model while working closely with other domain experts who are frequently not co-located with the geologist. Time-critical analysis can be hampered by the fact that reservoirs, which are inherently 3D objects, are traditionally viewed with 2D screens. The system presented here allows the geologic model to be rendered as a hologram in multiple locations to allow domain experts to collaborate and analyze the reservoir in real-time. Collaboration on 3D models has not changed significantly in a generation. For co-located personnel the approach is to gather around a 2D screen. For remote personnel the approach has been sharing a model through a 2D screen along with video chat. These approaches are not optimal for many reasons. Over the years various attempts have been tried to enhance the collaboration experience and have all fallen short. In particular virtual reality (VR) has been seen as a solution to this problem. However, we have found that augmented reality (AR) is a much better solution for many subtle reasons which are explored in the paper. AR has already acquired an impressive track record in various industries. AR will have applications in nearly all industries. For various historical reasons, the uptake for AR is much faster in some industries than others. It is too early to tell whether the use of augmented reality in geological applications will be transformative, however the results of this initial work are promising.

scholarly journals Alexander Lamb Cullen OBE. 30 April 1920—27 December 2013

2018 ◽  
Vol 64 ◽  
pp. 131-148
Author(s):  
J. Brian Davies
Keyword(s):  
Electromagnetic Waves ◽  
Electrical Engineering ◽  
Measurement Techniques ◽  
Science And Engineering ◽  
Engineering Research ◽  
British Science ◽  
Wide Range ◽  
The Media ◽  
Great Sense ◽  
The Times

Alex Cullen combined the sharpest of scientific minds with a gentle personality and a great sense of humour. He was Professor and Head of the Department of Electrical Engineering at Sheffield from 1955 to 1967, and then Head of the Department of Electrical Engineering at University College London (UCL) until 1980. He continued his research there as a Science and Engineering Research Council Senior Fellow until 1985, and for some years as Research Fellow of UCL. His research concerned electromagnetic waves over a wide range of microwave devices and measurement techniques, the latter at a fundamental level. These contributions were of a highly innovative and ‘ground-breaking’ nature. He was appointed OBE in 1960, and elected Fellow of the Royal Society in 1977. He was an accomplished jazz musician, playing drums and clarinet. He was a signatory of a letter to The Times in January 1986, calling on Prime Minister Margaret Thatcher to ‘Save British Science’. This led to the foundation of the Save British Science pressure group, now the Campaign for Science and Engineering (CaSE), which has built up an enviable reputation with politicians and the media in representing the concerns of scientists and engineers. When (now Sir) Eric Ash left UCL in 1985 to become Rector of Imperial College, he remarked that Alex was ‘the last gentleman in the business’.

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