scholarly journals A direct measurement method of quantum relaxation time

2020 ◽  
Author(s):  
Peng Zhang ◽  
Haoqi Tang ◽  
Chuanchuan Gu ◽  
Hong Wang ◽  
Guangfu Luo ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Direct Measurement ◽  
Polarization Effect ◽  
Optical Measurement ◽  
Physical Property ◽  
Plasma Resonance ◽  
Physical Parameters ◽  
Conduction Electrons ◽  
Condensed Matters ◽  
Bound Electrons

Abstract Quantum relaxation time of electrons in condensed matters is the most important physical property while its direct measurement has been elusive for a century. Here, we report a breakthrough that allows us to directly determine quantum relaxation time at zero and non-zero frequencies using optical measurement. Through dielectric loss function, we connect bound electron effect to the physical parameters of plasma resonance and find an extra term of quantum relaxation time due to inelastic scattering between bound electrons and conduction electrons at non-zero frequencies. We demonstrate here that the frequency dependent inelastic polarization effect of bound electrons is the dominating contribution on quantum relaxation time of conduction electrons at optical frequencies and elastic polarization effect of bound electrons also dramatically changes the plasma resonance frequency through effective screening to charge carriers.

scholarly journals Spin-lattice relaxation time of conduction electrons inMgB2

2007 ◽  
Vol 76 (2) ◽  
Author(s):  
F. Simon ◽  
F. Murányi ◽  
T. Fehér ◽  
A. Jánossy ◽  
L. Forró ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Conduction Electrons ◽  
Spin Lattice Relaxation Time ◽  
Spin Lattice

Polymer Solution with Very Low Relaxation Time: A Combined Numerical-Experimental Determination Strategy

2021 ◽  
Author(s):  
Guillaume Maîtrejean ◽  
Denis C D Roux ◽  
Maxime Rosello ◽  
Pascal Jay ◽  
Jean Xing ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Experimental Determination ◽  
Polymer Solution ◽  
Mixed Strategy ◽  
Numerical Approach ◽  
Physical Parameters ◽  
Test Case ◽  
Ink Jet ◽  
Elastic Polymer ◽  
Numerical Strategy

Abstract For very low relaxation time (i.e. lesser than a microsecond) viscoelastic fluid experimental determination is difficult, if not impossible. In the present work the relaxation time measurement of a weakly elastic polymer solution, too low to be measured using classical rheometry techniques, is assessed using a mixed experimental-numerical strategy. First the fluid is rheologically assessed, by measuring its shear viscosity, surface tension and density. Then the relaxation time is determined by comparing the jetting of polymer solution from a Continuous Ink-Jet (CIJ) device experimentally and numerically. The numerical approach is first validated using test case and a viscoelastic Oldroyd-B model is then used to model the experimental solution. The relaxation time is then a parameter allowing us to fit numerical simulation onto experimental results. This mixed strategy is particularly convenient for weakly elastic solution for which physical parameters can not be measured using experimental rheometry setup.

scholarly journals Experimental Comparison of Outdoor Baseline Measurements by Different Methods

2019 ◽  
Vol 131 ◽  
pp. 01057
Author(s):  
Youyi Gu ◽  
Li Wang ◽  
Fengzhuo Xiang ◽  
Wen Ouyang ◽  
Lixing Jiang
Keyword(s):  
Direct Measurement ◽  
High Precision ◽  
Optical Measurement ◽  
Experimental Results ◽  
Experimental Comparison ◽  
Total Station ◽  
Length Standard ◽  
Gnss Receivers ◽  
Surveying And Mapping

Outdoor baseline is the special length standard in the field of surveying and mapping, it can be used to verify the addition and multiplication constants of the total station and other photoelectric rangefinders. In order to ensure the authenticity, accuracy and reliability of verification results, conducting outdoor baseline traceability periodically is essential. At present, direct measurement by 24m invar tape or high precision electro-optical measurement is mainly used to achieve the traceability of outdoor baseline in China. Based on Shenyang baseline field, high precision rangefinder μ-base, 24m invar tape and high precision GNSS receivers are used for comparison experiments, and the experimental results are analyzed.

scholarly journals Physical parameters of selected Gaia mass asteroids

2020 ◽  
Vol 638 ◽  
pp. A11
Author(s):  
E. Podlewska-Gaca ◽  
A. Marciniak ◽  
V. Alí-Lagoa ◽  
P. Bartczak ◽  
T. G. Müller ◽  
...  
Keyword(s):  
Thermal Inertia ◽  
Physical Property ◽  
Physical Parameters ◽  
Good Precision ◽  
Main Belt ◽  
Shape Models ◽  
Solar System Bodies ◽  
Fundamental Physical Property ◽  
Thermophysical Modeling ◽  
The Masses

Context. Thanks to the Gaia mission, it will be possible to determine the masses of approximately hundreds of large main belt asteroids with very good precision. We currently have diameter estimates for all of them that can be used to compute their volume and hence their density. However, some of those diameters are still based on simple thermal models, which can occasionally lead to volume uncertainties as high as 20–30%. Aims. The aim of this paper is to determine the 3D shape models and compute the volumes for 13 main belt asteroids that were selected from those targets for which Gaia will provide the mass with an accuracy of better than 10%. Methods. We used the genetic Shaping Asteroids with Genetic Evolution (SAGE) algorithm to fit disk-integrated, dense photometric lightcurves and obtain detailed asteroid shape models. These models were scaled by fitting them to available stellar occultation and/or thermal infrared observations. Results. We determine the spin and shape models for 13 main belt asteroids using the SAGE algorithm. Occultation fitting enables us to confirm main shape features and the spin state, while thermophysical modeling leads to more precise diameters as well as estimates of thermal inertia values. Conclusions. We calculated the volume of our sample of main-belt asteroids for which the Gaia satellite will provide precise mass determinations. From our volumes, it will then be possible to more accurately compute the bulk density, which is a fundamental physical property needed to understand the formation and evolution processes of small Solar System bodies.

Optical measurement of the director relaxation time in a periodically reoriented nematic liquid crystal

1999 ◽  
Vol 86 (6) ◽  
pp. 3042-3047 ◽  
Author(s):  
P. L. Papadopoulos ◽  
H. M. Zenginoglou ◽  
J. A. Kosmopoulos
Keyword(s):  
Relaxation Time ◽  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Optical Measurement

The Preliminary Results of Rock Physical Properties in Yudu-Ganxian Ore Concentration Area

2013 ◽  
Vol 813 ◽  
pp. 225-229
Author(s):  
Bin Zhao ◽  
Jian Guo Li ◽  
Shao Wei Sun ◽  
Xin Peng Zhou ◽  
Zhen Bin Wang ◽  
...  
Keyword(s):  
Physical Properties ◽  
Research Method ◽  
Three Dimensional ◽  
Physical Property ◽  
Physical Parameters ◽  
Distribution Characteristics ◽  
Actual Distribution ◽  
New Information ◽  
Metallogenic Prognosis ◽  
Rock Physical Property

As the lack of work on comprehensive rock physical properties in deep geophysical exploration in Yudu-Ganxian ore concentration area, this paper focuses in comprehensive and systematic study about the comprehensive rock physical properties in this area. Known from the rock (ore) actual distribution in this area, this paper presents the comprehensive rock physical properties research method of the area, which use varieties of techniques to collect specimens systematic, determine the physical parameters, and even study the distribution characteristics and variation law of rock (ore) integrated rock physical properties parameters. In this paper, the results can provide the new information about integrated rock physical property parameters for understanding and explaining the integrated geophysical anomaly, providing the basis for the future in Nanling to carry out deep geophysical three-dimensional exploration and deep metallogenic prognosis.

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