A Novel, Efficient, Unit Circle-Based, Method for Positioning and Operating Cryo-Surgical Probes in Convex Target Areas

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Zaur Magalov ◽  
Shitzer Avraham ◽  
Degani David
Keyword(s):  
Unit Circle ◽  
Dynamic Performance ◽  
Radius Of Curvature ◽  
Target Area ◽  
Lethal Temperature ◽  
Single Probe ◽  
Novel Method ◽  
Specific Distance ◽  
Predetermined Number

Abstract A novel method for positioning and operating needle-like cryo-surgical probes in 2D convex target areas is presented. The method is based on the recorded dynamic performance of a single probe, termed “unit circle,” (UC) embedded in a semi-infinite, tissue-like medium. Up to 15 cryo-probes, inserted into the same depth, are operated uniformly for 2–5 min. A predetermined number of probes are rearranged inside the target area until a “tight configuration” is obtained. The probes are initially arranged inside the target area such that the “lethal temperature” circles produced by them are tangent to its contour and to both adjacent lethal temperature circles. Subsequently, all probes are repositioned inwardly, each at a specific distance that depends on the local radius of curvature of the target area. Resulting total “defect areas”—internal and external—for a number of demonstrated cases, amounted to between 2.5% and 7.6% of the target area. The lower values of the defect areas were obtained with increasing numbers of inserted probes coupled with shorter operating times. Possible freezing damages to regions beyond the target area were reduced by up to about 30% for these cases. Similar results were obtained for a case of combined convex-concave target area, treated with additional, externally inserted, heating probes.

Parameter Optimization of Virtual Impedance for Parallel Inverter

2014 ◽  
Vol 986-987 ◽  
pp. 1973-1976
Author(s):  
Ping Wang ◽  
Liu Yang
Keyword(s):  
Parameter Optimization ◽  
Dynamic Performance ◽  
Design Methods ◽  
New Method ◽  
Conventional Design ◽  
Equivalent Impedance ◽  
Novel Method ◽  
Virtual Impedance ◽  
Frequency Curves ◽  
Parallel Inverter

This paper deals with parameter optimization of virtual impedance of parallel inverter. Conventional design methods determine parameters by observing the changes of amplitude-frequency and phase frequency curves of the equivalent impedance. However, those methods always neglect the dynamic performance of inverters in parallel. This paper proposes a novel method to optimize the coefficients of virtual impedance and experiments show that new method improves the dynamic performance of parallel inverter effectively, as well as stability and flexibility.

scholarly journals Complex Hadamard Matrices from Sylvester Inverse Orthogonal Matrices

2009 ◽  
Vol 16 (04) ◽  
pp. 387-405 ◽  
Author(s):  
Petre Diţă
Keyword(s):  
Unit Circle ◽  
Hadamard Matrices ◽  
Orthogonal Matrices ◽  
Novel Method ◽  
Free Parameters

A novel method to obtain parametrizations of complex inverse orthogonal matrices is provided. These matrices are natural generalizations of complex Hadamard matrices which depend on complex parameters. The method we use is via doubling the size of inverse complex conference matrices. When the free parameters take values on the unit circle the inverse orthogonal matrices transform into complex Hadamard matrices, and in this way we find new parametrizations of Hadamard matrices for dimensions n = 8, 10, and 12.

scholarly journals Cast Shadow Detection for Surveillance System Based on Tricolor Attenuation Model

2011 ◽  
Vol 2-3 ◽  
pp. 635-639
Author(s):  
Lin Lin Zhu ◽  
Jian Dong Tian ◽  
Yan Dong Tang ◽  
Jian Da Han
Keyword(s):  
Computer Vision ◽  
Surveillance System ◽  
Moving Target ◽  
Target Area ◽  
Attenuation Model ◽  
Cast Shadow ◽  
Outdoor Scenes ◽  
Novel Method ◽  
Relationship Of ◽  
The Relationship

Shadows bring some undesirable problems in computer vision, such as object detecting in outdoor scenes. In this paper, we propose a novel method for cast shadow detecting for moving target in surveillance system. This measure is based on tricolor attenuation model, which describes the relationship of three color channel’s attenuation in image when shadow happens. According to this relationship, the cast shadow is removed from the detected moving area, only the target area is left. Some experiments were done, and their results validate the performance of our method.

Image Feature Extraction of Moment of Inertia Based on Otsu Threshold Segmentation

2013 ◽  
Vol 756-759 ◽  
pp. 3157-3161 ◽  
Author(s):  
Qing Liu ◽  
Li Ming Zhao ◽  
Li Jun Zhang
Keyword(s):  
Feature Extraction ◽  
Binary Image ◽  
Moment Of Inertia ◽  
Image Feature ◽  
Target Area ◽  
Extraction Algorithm ◽  
Extraction Parameter ◽  
Novel Method ◽  
Simple Extraction ◽  
Binary Image Processing

In order to better extract image feature and recognition, a novel feature extraction algorithm of the binary image processing using Otsu combined with normalized moment of inertia (NMI) is put forward. Firstly, the image is processed into binary image and the target area is effectively segmented utilizing Otsu algorithm based on the criteria of maximal variance between-class , secondly, the NMI feature of the binary image is extracted, and finally, the extraction NMI feature is used in image recognition. Experimental results show that NMI feature of the binary image have the ability of anti-geometric distortions (translation, rotation and scaling, TRS), and anti-brightness distortions, the novel method have characteristics of simple extraction approach, little extraction parameter, easy implementation, and strong robustness.

Automatic TEM Sample Preparation

1999 ◽  
Author(s):  
Wayne D. Kaplan ◽  
Kim Kisslinger ◽  
Ron Oviedo ◽  
Efrat M. Raz ◽  
Colin Smith
Keyword(s):  
Sample Preparation ◽  
Focused Ion Beam ◽  
Preparation Method ◽  
Ion Beam ◽  
Semiconductor Industry ◽  
Target Area ◽  
Transmission Electron ◽  
Sample Edge ◽  
Added Benefit ◽  
Specific Distance

Abstract The rising demand in the semiconductor industry for higher spatial resolution in the analysis of device defects has focused attention on the use of transmission electron microscopy (TEM). However, conventional TEM sample preparation may be difficult and time-consuming, and depending on the operator may result in a low yield of quality specimens. One solution to this problem is the use of focused ion beam (FIB) milling for the final stage of TEM sample preparation. However, specimens have to be mechanically thinned prior to FIB processing, and the need to characterize specific devices requires a pre-FIB preparation method to isolate specific regions on the wafer. An innovative and automated solution that isolates specific devices and prepares TEM specimens for subsequent thinning by FIB has been developed. Based on controlled microcleaving technology, the system automatically performs the pre-FIB preparation in less than 30 minutes. An important added benefit is that the target area to be analyzed can be positioned at a specific distance from the sample edge, thereby facilitating the final FIB milling stage. The thinned specimen is automatically packaged for subsequent FIB processing and TEM. Details of the method and examples showing TEM results from tungsten filled vias are presented.

scholarly journals Measurement Vertex Position of a Large Aspheric Mirror

2019 ◽  
Vol 9 (6) ◽  
pp. 1038 ◽  
Author(s):  
Jie Li ◽  
Fengtao Yan ◽  
Lin Chen ◽  
Jie Yang ◽  
Yongjian Wan
Keyword(s):  
Measurement Uncertainty ◽  
Measurement Accuracy ◽  
Mechanical Axis ◽  
Radius Of Curvature ◽  
Testing System ◽  
Laser Tracker ◽  
Position Measurement ◽  
Aspheric Mirror ◽  
Novel Method

We present a novel method to accurately measure the vertex position of a large aspheric mirror with a phasing measuring interferometer, a laser tracker, and a micro alignment telescope. The method consists of rotating the mirror by 180° about its mechanical axis and measuring the change in displacement. Use of a micro alignment telescope eliminates the need to adjust the mirror during the measurement, eases the alignment of the testing system, and improves the vertex position measurement accuracy. Using this method, we measured the vertex position of an aspheric mirror 1 m in diameter and 2 m in radius of curvature. The vertex position measurement uncertainty is 88 μm.

Dynamic Performance of the Bearing-Rotor System in the Ultra-High Speed Electric Spindle with a Additional Supporting System Make up of the Permanent Magnetic Bearings

2011 ◽  
Vol 295-297 ◽  
pp. 2294-2299
Author(s):  
Song Sheng Li ◽  
Hua Wei Mao ◽  
Ping Chen ◽  
Xiao Huang ◽  
Peng Zhou ◽  
...  
Keyword(s):  
Permanent Magnet ◽  
High Speed ◽  
Permanent Magnets ◽  
Dynamic Performance ◽  
Rotor System ◽  
Magnetic Bearings ◽  
Supporting System ◽  
Ultra High Speed ◽  
Novel Method ◽  
Additional Support

A novel method, aiming at solving the problem that the ultra-high-speed electric spindle tends to vibrate as its stiffness is small, using the repulsion of permanent magnets based on the theory that repulsion increased while the two magnets come close, is provided in this paper to design a electric spindle within additional support bearing system consist of two radial permanent magnet rings against each other. This paper also analyses the dynamic performance of radial permanent magnet bearings additional supporting system for ultra-high speed electric rotor system, result shows that the radial permanent magnetic bearings additional supporting system designed for improving the critical speed of the rotor system, reducing the rotor radial dynamic response, can effectively improve the dynamic performance and operational stability of ultra-high speed electric spindle rotor system.

Research on the Seismic Response Characteristic under Different Curvature Radios

2011 ◽  
Vol 243-249 ◽  
pp. 536-540
Author(s):  
Qing Ning Li ◽  
Feng Jie Jiang ◽  
Tian Li Wang ◽  
Jian Pen Sun ◽  
Lei Juan Wang
Keyword(s):  
Finite Element ◽  
Response Spectrum ◽  
Dynamic Performance ◽  
Single Point ◽  
Time History ◽  
Response Characteristic ◽  
Radius Of Curvature ◽  
Curvature Radius ◽  
Seismic Action ◽  
Finite Element Program

The curvature radius is a very important factor which influences the dynamic performance of the curved continuous long bridge badly. This paper based on the practical engineering, with large finite element program, established the curved continuous long bridge space finite element calculation model. Respectively by response spectrum method and the time-history response method, consider single-point excitation and multi-support excitation seismic action, Analyzes different radius of curvature in curved continuous long bridge self-vibration frequency, internal force and displacement on the differences, and given the internal relations between the difference and the curvature radius, offer some reasonable design reference suggestion for curved continuous long bridge of the radius of curvature.

On the improvement of the dynamic performance of dielectric elastomer actuators for active compression

2018 ◽  
Vol 29 (5) ◽  
pp. 986-997 ◽  
Author(s):  
Hamza Edher ◽  
Armaghan Salehian
Keyword(s):  
Dynamic Performance ◽  
Hold Time ◽  
Compressive Force ◽  
Dielectric Elastomer ◽  
Output Curve ◽  
Dielectric Elastomer Actuator ◽  
Dielectric Elastomer Actuators ◽  
Low Weight ◽  
Output Force ◽  
Novel Method

Dielectric elastomer actuators have been considered for an increasing number of applications due to their desirable characteristics of low weight, high strain outputs and favourable material costs. The present work describes the use of a dielectric elastomer actuator in conjunction with a belt mechanism to apply cyclic active compression. The belt mechanism helps convert the stress relaxation upon the voltage application to the dielectric elastomer actuator to a compressive force. Testing is conducted using multi-layered silicone–based dielectric elastomer actuators. A novel method of dynamically charging dielectric elastomer actuators through manipulating the input signal shape, termed the hold method, is introduced. Using this method, cyclic actuation strain output can be increased by 24% with insignificant change in actuation output curve shape. Furthermore, the effect of pre-stretch ratios on the output force amplitudes is characterized. The optimized hold time parameters obtained through cyclic dielectric elastomer force and strain are utilized for active compression physiological testing and a pressure gradient of 10 mmHg is achieved.

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