Exploration of the coupling between thrust and interference in Taiji-1

2021 ◽  
pp. 2140002
Author(s):  
Juan Wang ◽  
Ran Yang ◽  
Yu Niu ◽  
Keyword(s):  
Laser Interferometer ◽  
Inertial Sensor ◽  
Optical Path Difference ◽  
Path Difference ◽  
Integration Time ◽  
Maximum Effect ◽  
Comprehensive Understanding ◽  
Satellite Platform ◽  
Micro Propulsion ◽  
The Relationship

As the first technology verification satellite of the space-based gravitational wave detection in China, Taiji-1 has tested the high-precision space laser interferometer, the inertial sensor, the micro thruster and the hyperstatic satellite platform in orbit. The micro thruster plays an important role in the micro propulsion system. The purposes of the research are to investigate the relationship between the thrust and the interference, and then get a comprehensive understanding about the maximum effect of the thrust in Taiji-1. The transfer function between the thrust and the optical path difference fluctuations is established through the modeling, the simulation and the data postprocessing of Taiji-1. In addition, the maximum effect of the thrust in Taiji-1 is about 32 pm/[Formula: see text] with an integration time of 100 s. It can be neglected compared to the requirement of 100 pm/[Formula: see text] for the interferometer stability in Taiji-1.

Preliminary simulation analysis of the temperature fluctuation effect on Taiji-1 Laser interferometer

2021 ◽  
pp. 2140003
Author(s):  
Xiaoqin Deng ◽  
Ran Yang ◽  
Yu Niu ◽  
Keyword(s):  
Temperature Fluctuation ◽  
Laser Interferometer ◽  
Simulation Analysis ◽  
Optical Path Difference ◽  
Path Difference ◽  
Optical Simulation ◽  
The Finite Element Method ◽  
Fluctuation Noise ◽  
Fluctuation Amplitude ◽  
Simulation Results

Space-borne gravitational wave detection imposes a demanding requirement on the sensitivity of the laser interferometer. Among all disturbances that affect the measurement accuracy of the laser interferometer, temperature fluctuations contribute significantly. In this paper, the structure model and the interference path design of Taiji-1 laser interferometer have been used to conduct a preliminary simulation analysis of the temperature fluctuation noise through the finite element method. The temperature, the displacement and the optical path difference fluctuations have been obtained and theoretically analyzed. The preliminary simulation results are consistent with the theoretical analysis, which shows that the thermal–structural–optical simulation scheme adopted in this paper is reasonable. With the preliminary simulation results and the actual temperature control of Taiji-1 laser interferometer, we estimate that in Taiji-1 laser interferometer system, the temperature fluctuation is below the order of mK, the node displacement is within [Formula: see text][Formula: see text]pm, and the interference arm length difference fluctuation amplitude of the laser interferometer is also within [Formula: see text][Formula: see text]pm.

The characteristics of laser scattered by droplets

2019 ◽  
Vol 33 (21) ◽  
pp. 1950236
Author(s):  
Bin Zhang ◽  
Yu Zhang ◽  
Yunxi Li ◽  
Qingyan Li ◽  
Yuru Bai ◽  
...  
Keyword(s):  
Geometric Optic ◽  
Optical Path Difference ◽  
Path Difference ◽  
Optical Path ◽  
Laser Radar ◽  
Size And Shape ◽  
Analytic Expression ◽  
Raindrop Size ◽  
Bad Weather ◽  
The Relationship

Droplets are the primary factors which influence laser transmitting in bad weather. This paper researches the analytic expression of droplets influencing the laser, which is based on the geometric optic theory and distribution of raindrop size and shape. In this paper, the relationship between the incidence and emergence angle of droplets is discussed. The effects of an individual raindrop on Ladar divergence angle, illuminance and optical path difference are investigated, and then the cumulated influence of a large quantity of raindrops is analyzed. The illuminance of scanning the targets and laser radar received by the detector is presented.

Peak-to-peak tracking method for measurement of optical path difference: Revisited

Optik ◽  
2015 ◽  
Vol 126 (24) ◽  
pp. 5420-5422
Author(s):  
H.H. Ley ◽  
A. Yahaya ◽  
Y. Munajat
Keyword(s):  
Optical Path Difference ◽  
Path Difference ◽  
Optical Path ◽  
Tracking Method ◽  
Peak Tracking

Relationship between self-care and comprehensive understanding of heart failure and its signs and symptoms

2017 ◽  
Vol 17 (6) ◽  
pp. 496-504 ◽  
Author(s):  
Kyoung Suk Lee ◽  
Debra K Moser ◽  
Kathleen Dracup
Keyword(s):  
Heart Failure ◽  
Confidence Interval ◽  
Self Care ◽  
Signs And Symptoms ◽  
Comprehensive Understanding ◽  
Behavior Scale ◽  
Heart Failure Exacerbation ◽  
The Relationship ◽  
Different Levels ◽  
Care Behavior

Background: Although incomplete understanding of heart failure and its signs and symptoms appears to be a barrier to successful self-care, there are few studies examining the relationship between self-care and levels of comprehensive understanding of heart failure and its signs and symptoms. Aim: To determine whether incomplete understanding of heart failure and its signs and symptoms is associated with self-care in heart failure patients who were recently discharged from the hospital due to heart failure exacerbation. Methods: Patients completed the nine-item European Heart Failure Self-care Behavior scale and questionnaire to assess knowledge of heart failure and its signs and symptoms. Three groups were formed by their different levels of understanding of heart failure and its signs and symptoms. Multivariable linear regression was used to determine whether these three levels of understanding groups predicted self-care after controlling for demographic and clinical variables. Results: Of 571 patients 22.1%, 40.1% and 37.8% had poor, moderate, and complete understanding, respectively. Compared with patients in the poor understanding group, patients in complete and moderate understanding groups were more likely to have better adherence to self-care activities (standardized β = −0.14, 95% confidence interval −3.41, −0.47; standardized β = −0.19, 95% confidence interval −4.26, −1.23, respectively). Conclusions: Fewer than half of the patients had a comprehensive understanding of heart failure and its signs and symptoms, which was associated with poor self-care. Our study suggests that patient education should include contents to promote comprehensive understanding of heart failure and its symptoms, as well as the importance of self-care behaviors.

Optical T-Bench Method for Measurement of Optical Path Difference

1963 ◽  
Vol 1 (6) ◽  
Author(s):  
Francis E. Washer ◽  
Walter R. Darling
Keyword(s):  
Optical Path Difference ◽  
Path Difference ◽  
Optical Path

Thermo-Fluid Design Simulation of Nd3+ POCl3 Transverse Flow Liquid Laser Cavity

2021 ◽  
pp. 1-31
Author(s):  
Vinod Singh ◽  
Gaurav Singhal ◽  
Prabal Talukdar
Keyword(s):  
Refractive Index ◽  
Temperature Gradient ◽  
Flow Rate ◽  
Optical Pumping ◽  
Gain Medium ◽  
Optical Path Difference ◽  
Path Difference ◽  
Transverse Flow ◽  
Optical Path ◽  
Liquid Laser

Abstract CFD based thermal design of a transverse flow optical cavity is carried out for 1 kW Nd3+ POCl3 liquid laser source to investigate temperature and velocity distribution in the optical pumping region of the cavity. Temperature gradient and turbulence both affect the refractive index of the liquid gain medium, which results in optical path difference, divergence and hence, poorer quality of the laser beam. The main purpose of this design is to achieve uniform flow and least temperature gradient in the optical pumping region so that the optical path difference can be minimized and a good beam quality can be achieved. CFD model has been developed for carrying out thermo-fluid simulations for this thermal system and based on these simulations, an optimum geometry of inlet ports along with their position from optical pumping region have been proposed. A user defined function (UDF) is incorporated for the input of spatially varying heat source term in each cell of the optical pumping region of the cavity. Variations in refractive index and optical path difference are estimated from the temperature data using another UDF. Simulation reveals that mass flow rate between 1.5 kg/s to 2.0 kg/s maintains the optical homogeneity of gain medium. Preliminary experiments have been carried out to demonstrate the effect of flow rate on the beam divergence and thereby exhibiting the importance of present simulation work.

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