The Electromagnetic Parameters' Impact of λ/4 Type Dielectric Absorber on Absorbing Properties

2014 ◽  
Vol 644-650 ◽  
pp. 3593-3596
Author(s):  
Hui Chao Zhao ◽  
Wan Jun Hao ◽  
Ying Ying Yi ◽  
Yi Feng Dong ◽  
Xin Dan Yu
Keyword(s):  
Imaginary Part ◽  
High Performance ◽  
Membrane Resistance ◽  
Maximum Absorption ◽  
Electromagnetic Parameters ◽  
The Real

This paper studies electromagnetic parameters' impact of λ/4 type dielectric absorber on absorbing properties. Calculation shows that the maximum absorption amount is corresponding to specific values of K and R when absorber's permittivity is stable, when the thickness of material is determined and the real part permittivity is increased, the absorption peaks move to lower frequency and reduce the distance between adjacent peaks, while the imaginary part of permittivity and resistance of membrane resistance only affect absorption peaks' amount but have no effect on the peaks' position. Accordingly, it is reasonable to adjust the material's electromagnetic parameters according to the above rule when the high-performance λ/4 dielectric-type absorber is prepared.

scholarly journals How Relevant Is It to Use Mineral Proxies to Mimic the Atmospheric Reactivity of Natural Dust Samples? A Reactivity Study Using SO2 as Probe Molecule

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 282
Author(s):  
Darya Urupina ◽  
Manolis N. Romanias ◽  
Frederic Thevenet
Keyword(s):  
High Performance ◽  
Real Life ◽  
Complex Mixtures ◽  
Experimental Conditions ◽  
The Real ◽  
Atmospheric Processes ◽  
Real Effects ◽  
Mineral Aerosols ◽  
Life Impact ◽  
Reactivity Study

The experimental investigation of heterogeneous atmospheric processes involving mineral aerosols is extensively performed in the literature using proxy materials. In this work we questioned the validity of using proxies such as Fe2O3, FeOOH, Al2O3, MgO, CaO, TiO2, MnO2, SiO2, and CaCO3 to represent the behavior of complex mixtures of minerals, such as natural desert and volcanic dusts. Five volcanic dusts and three desert dusts were compared to a number of metal oxides, commonly used in the literature to mimic the behavior of desert dusts in the ability to form sulfites and sulfates on the surface exposed to SO2 gas. First, all samples were aged at room temperature, atmospheric pressure, under controlled experimental conditions of 175 ppm SO2 for 1 h under 30% of relative humidity. Second, they were extracted with 1% formalin and analyzed by High-Performance Liquid Chromatography (HPLC) to quantify and compare the amount of sulfites and sulfates formed on their surfaces. It was evidenced that under the experimental conditions of this study neither one selected pure oxide nor a mixture of oxides can adequately typify the behavior of complex mixtures of natural minerals. Therefore, to evaluate the real-life impact of natural dust on atmospheric processes it is of vital importance to work directly with the natural samples, both to observe the real effects of desert and volcanic dusts and to evaluate the relevancy of proposed proxies.

scholarly journals Complex q-Rung Orthopair Fuzzy Aggregation Operators and Their Applications in Multi-Attribute Group Decision Making

Information ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 5 ◽  
Author(s):  
Liu ◽  
Mahmood ◽  
Ali
Keyword(s):  
Decision Making ◽  
Fuzzy Sets ◽  
Imaginary Part ◽  
Group Decision Making ◽  
Group Decision ◽  
Aggregation Operators ◽  
Uncertain Information ◽  
Membership Degree ◽  
The Real ◽  
Complex Valued

In this manuscript, the notions of q-rung orthopair fuzzy sets (q-ROFSs) and complex fuzzy sets (CFSs) are combined is to propose the complex q-rung orthopair fuzzy sets (Cq-ROFSs) and their fundamental laws. The Cq-ROFSs are an important way to express uncertain information, and they are superior to the complex intuitionistic fuzzy sets and the complex Pythagorean fuzzy sets. Their eminent characteristic is that the sum of the qth power of the real part (similarly for imaginary part) of complex-valued membership degree and the qth power of the real part (similarly for imaginary part) of complex-valued non‐membership degree is equal to or less than 1, so the space of uncertain information they can describe is broader. Under these environments, we develop the score function, accuracy function and comparison method for two Cq-ROFNs. Based on Cq-ROFSs, some new aggregation operators are called complex q-rung orthopair fuzzy weighted averaging (Cq-ROFWA) and complex q-rung orthopair fuzzy weighted geometric (Cq-ROFWG) operators are investigated, and their properties are described. Further, based on proposed operators, we present a new method to deal with the multi‐attribute group decision making (MAGDM) problems under the environment of fuzzy set theory. Finally, we use some practical examples to illustrate the validity and superiority of the proposed method by comparing with other existing methods.

scholarly journals Exploring sensorimotor performance and user experience within a virtual reality golf putting simulator

2020 ◽  
Author(s):  
David J. Harris ◽  
Gavin Buckingham ◽  
Mark R. Wilson ◽  
Jack Brookes ◽  
Faisal Mushtaq ◽  
...  
Keyword(s):  
Virtual Reality ◽  
Construct Validity ◽  
Real World ◽  
High Performance ◽  
Task Demands ◽  
Self Report ◽  
The Real ◽  
Task Load ◽  
Golf Putting ◽  
Effective Transfer

Abstract In light of recent advances in technology, there has been growing interest in virtual reality (VR) simulations for training purposes in a range of high-performance environments, from sport to nuclear decommissioning. For a VR simulation to elicit effective transfer of training to the real-world, it must provide a sufficient level of validity, that is, it must be representative of the real-world skill. In order to develop the most effective simulations, assessments of validity should be carried out prior to implementing simulations in training. The aim of this work was to test elements of the physical fidelity, psychological fidelity and construct validity of a VR golf putting simulation. Self-report measures of task load and presence in the simulation were taken following real and simulated golf putting to assess psychological and physical fidelity. The performance of novice and expert golfers in the simulation was also compared as an initial test of construct validity. Participants reported a high degree of presence in the simulation, and there was little difference between real and virtual putting in terms of task demands. Experts performed significantly better in the simulation than novices (p = .001, d = 1.23), and there was a significant relationship between performance on the real and virtual tasks (r = .46, p = .004). The results indicated that the simulation exhibited an acceptable degree of construct validity and psychological fidelity. However, some differences between the real and virtual tasks emerged, suggesting further validation work is required.

One Method to Construct the S-Box Based on Improved Chaos Map

2014 ◽  
Vol 651-653 ◽  
pp. 2164-2167
Author(s):  
Hang Zhang ◽  
Xiao Jun Tong
Keyword(s):  
Imaginary Part ◽  
Logistic Map ◽  
Block Ciphers ◽  
Mandelbrot Set ◽  
New Method ◽  
Hénon Map ◽  
Henon Map ◽  
The Real

Many methods of constructing S-box often adopt the classical chaotic equations. Yet study found that some of the chaotic equations exists drawbacks. Based on that, this paper proposed a new method to generate S-Box by improving the Logistic map and Henon map, and combining the real and imaginary part of complex produced by the Mandelbrot set. By comparing with several other S-boxes proposed previously, the results show the S-box here has better cryptographic properties. So it has a good application prospect in block ciphers.

scholarly journals GAP EQUATION IN SCALAR FIELD THEORY AT FINITE TEMPERATURE

1999 ◽  
Vol 14 (04) ◽  
pp. 257-266
Author(s):  
KRISHNENDU MUKHERJEE
Keyword(s):  
Field Theory ◽  
Perturbation Theory ◽  
Scalar Field ◽  
Imaginary Part ◽  
Finite Temperature ◽  
Thermal Mass ◽  
Scalar Field Theory ◽  
Gap Equation ◽  
The Real

We investigate the two-loop gap equation for the thermal mass of hot massless g2ϕ4 theory and find that the gap equation itself has a nonzero finite imaginary part. This implies that it is not possible to find the real thermal mass as a solution of the gap equation beyond g2 order in perturbation theory. We have solved the gap equation and obtained the real and imaginary parts of the thermal mass which are correct up to g4 order in perturbation theory.

FACE REPRESENTATION WITH GRADIENT ORIENTATIONS AND EULER MAPPING: APPLICATION TO FACE RECOGNITION

2014 ◽  
Vol 28 (08) ◽  
pp. 1456014 ◽  
Author(s):  
ZHAOKUI LI ◽  
LIXIN DING ◽  
YAN WANG ◽  
JINRONG HE
Keyword(s):  
Face Recognition ◽  
Imaginary Part ◽  
Feature Vector ◽  
Low Frequency ◽  
Subspace Learning ◽  
The Real ◽  
Face Representation ◽  
Central Pixel ◽  
Low Dimensional ◽  
Two Stages

This paper proposes a simple, yet very powerful local face representation, called the Gradient Orientations and Euler Mapping (GOEM). GOEM consists of two stages: gradient orientations and Euler mapping. In the first stage, we calculate gradient orientations of a central pixel and get the corresponding orientation representations by performing convolution operator. These representation results display spatial locality and orientation properties. To encompass different spatial localities and orientations, we concatenate all these representation results and derive a concatenated orientation feature vector. In the second stage, we define an explicit Euler mapping which maps the space of the concatenated orientation into a complex space. For a mapping image, we find that the imaginary part and the real part characterize the high frequency and the low frequency components, respectively. To encompass different frequencies, we concatenate the imaginary part and the real part and derive a concatenated mapping feature vector. For a given image, we use the two stages to construct a GOEM image and derive an augmented feature vector which resides in a space of very high dimensionality. In order to derive low-dimensional feature vector, we present a class of GOEM-based kernel subspace learning methods for face recognition. These methods, which are robust to changes in occlusion and illumination, apply the kernel subspace learning model with explicit Euler mapping to an augmented feature vector derived from the GOEM representation of face images. Experimental results show that our methods significantly outperform popular methods and achieve state-of-the-art performance for difficult problems such as illumination and occlusion-robust face recognition.

scholarly journals Stiffness of sphere–plate contacts at MHz frequencies: dependence on normal load, oscillation amplitude, and ambient medium

2015 ◽  
Vol 6 ◽  
pp. 845-856 ◽  
Author(s):  
Jana Vlachová ◽  
Rebekka König ◽  
Diethelm Johannsmann
Keyword(s):  
Imaginary Part ◽  
Coulomb Friction ◽  
Ambient Medium ◽  
Normal Load ◽  
Contact Stiffness ◽  
Oscillation Amplitude ◽  
Partial Slip ◽  
Squeeze Flow ◽  
Frictional Stress ◽  
The Real

The stiffness of micron-sized sphere–plate contacts was studied by employing high frequency, tangential excitation of variable amplitude (0–20 nm). The contacts were established between glass spheres and the surface of a quartz crystal microbalance (QCM), where the resonator surface had been coated with either sputtered SiO2 or a spin-cast layer of poly(methyl methacrylate) (PMMA). The results from experiments undertaken in the dry state and in water are compared. Building on the shifts in the resonance frequency and resonance bandwidth, the instrument determines the real and the imaginary part of the contact stiffness, where the imaginary part quantifies dissipative processes. The method is closely analogous to related procedures in AFM-based metrology. The real part of the contact stiffness as a function of normal load can be fitted with the Johnson–Kendall–Roberts (JKR) model. The contact stiffness was found to increase in the presence of liquid water. This finding is tentatively explained by the rocking motion of the spheres, which couples to a squeeze flow of the water close to the contact. The loss tangent of the contact stiffness is on the order of 0.1, where the energy losses are associated with interfacial processes. At high amplitudes partial slip was found to occur. The apparent contact stiffness at large amplitude depends linearly on the amplitude, as predicted by the Cattaneo–Mindlin model. This finding is remarkable insofar, as the Cattaneo–Mindlin model assumes Coulomb friction inside the sliding region. Coulomb friction is typically viewed as a macroscopic concept, related to surface roughness. An alternative model (formulated by Savkoor), which assumes a constant frictional stress in the sliding zone independent of the normal pressure, is inconsistent with the experimental data. The apparent friction coefficients slightly increase with normal force, which can be explained by nanoroughness. In other words, contact splitting (i.e., a transport of shear stress across many small contacts, rather than a few large ones) can be exploited to reduce partial slip.

Key Techniques and Advances of Grinding/Milling Spiral Flutes on NC Machines with Multi-Axis Linkage

2008 ◽  
Vol 392-394 ◽  
pp. 1019-1024 ◽  
Author(s):  
Chun Jiang Xiang ◽  
Li Zhi Gu
Keyword(s):  
Mathematical Modeling ◽  
Error Compensation ◽  
High Performance ◽  
Automatic Generation ◽  
Error Modeling ◽  
The Real ◽  
Nc Code ◽  
Tool Interference ◽  
Key Techniques

Introduced systematically the forming principles and mathematical modeling of grinding/ milling spiral flutes with numeric control machines, overviewed the functions of multi-axis linkage and the determination technique of the number of the linkage axes, discussed the conversion technique of NC—STEP-NC code in programming with EXPRESS, presented advances of controlling systems with high performance. Much attention was paid to the explanation of the error modeling and the tool interference in the real machining with the error-compensation techniques. Trends were envisioned on key technique study of the forming principles for the spatial spiral flutes, function of multi-axes, tool interference in the real machining and simulation of the operation processing, as well as automatic generation of NC codes and the connection /compatibility of the codes with the mainline NC systems, in future.

SAVVIDY VACUUM IN SU(2) YANG–MILLS THEORY

2005 ◽  
Vol 20 (22) ◽  
pp. 1655-1662 ◽  
Author(s):  
DANIEL KAY ◽  
A. KUMAR ◽  
R. PARTHASARATHY
Keyword(s):  
Energy Density ◽  
Imaginary Part ◽  
Functional Integral ◽  
Quadratic Approximation ◽  
Effective Energy ◽  
The Real ◽  
Yang Mills ◽  
The One

The one-loop effective energy density of a pure SU (2) Yang–Mills theory in the Savvidy background is reconsidered. The stable and the unstable modes are identified. The stable modes are treated in the quadratic approximation. For the unstable modes, the full expansion including the cubic and the quartic terms in the fluctuations is used. The functional integral for the unstable modes is evaluated and added to the result for the stable modes. The resulting energy density coincides with the real part in the quadratic approximation of earlier studies and there is now no imaginary part.

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