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2021 ◽  
Vol 2083 (2) ◽  
pp. 022034
Author(s):  
Quanyong Su ◽  
Juan Liu ◽  
Xianmou Xue ◽  
Zheng Shi

Abstract Thermal control of high power density phased array antenna [1] has become a critical problem for onboard seeker which is confined by compact structure and harsh flight condition [2-4], different from land-based or airborne seekers. As a key technology, thermal control of onboard phased array antenna faces the challenge of high density power element as well as worse operating temperature. Using finite volume method as theoretic foundation of numerical simulation, this paper firstly calculates temperature field and fluid field via discrete control equation group, which is transformed from continuous integration equation group according to energy reservation equation. Next,2 kinds of phased array antenna with phase change energy storage and water cooling are designed and evaluated by thermal control performance simulation. Then advice is given for reasonable assembly after temperature distribution of phased array antenna is quantified under different assembly state with the influence of contact thermal resistance. At the end, precision of temperature simulation is verified with temperature test result of phased array antenna.


2021 ◽  
Author(s):  
Wenjun Su ◽  
Junkang Guo ◽  
Zhigang Liu ◽  
Kang Jia

Abstract Rotary-laser automatic theodolite (R-LAT) system is a distributed large-scale metrology system, which provides parallel measurement in scalable measurement room without obvious precision losing. Each of R-LAT emits two nonparallel laser planes to scan the measurement space via evenly rotation, while the photoelectric sensors receive these laser planes signals and performs the coordinate calculation based on triangulation. The accurate geometric parameters of the two laser planes plays a crucial role in maintaining the measurement precision of R-LAT system. Practically, the geometry of the two laser plane, which is termed as intrinsic parameters, is unknown after assembled. Therefore, how to figure out the accurate intrinsic parameters of each R-LAT is a fundamental question for the application of R-LAT system. This paper proposed an easily operated intrinsic parameter calibration method for R-LAT system with adopting coordinate measurement machine. The mathematic model of laser planes and the observing equation group of R-LAT are established. Then, the intrinsic calibration is formulated as a nonlinear least square problem that minimize the sum of deviations of target points and laser planes, and the ascertain of its initial guess is introduced. At last, experience is performed to verify the effectiveness of this method, and simulations are carried out to investigate the influence of the target point configuration on the accuracy of intrinsic parameters.


2021 ◽  
Author(s):  
X.D. Dongfang

Abstract Signal waves of the monotone increasing frequency detected by LIGO are universally considered to be gravitational waves of spiral binary stars, and the general theory of relativity is thus universally considered to have been confirmed by the experiments. Here we present a universal method for signal wave spectrum analysis, introducing the true conclusions of numerical calculation and image analysis of GW150914 signal wave. Firstly, numerical calculation results of GW150914 signal wave frequency change rate obey the com quantization law which needs to be accurately described by integers, and there is an irreconcilable difference between the results and the generalized relativistic frequency equation of the gravitational wave. Secondly, the assignment of the frequency and frequency change rate of GW10914 signal wave to the generalized relativistic frequency equation of gravitational wave constructs a non-linear equation group about the mass of wave source, and the computer image solution shows that the equation group has no GW10914 signal wave solution. Thirdly, it is not unique to calculate the chirp mass of the wave source from the different frequencies and change rates of the numerical relativistic waveform of the GW150914 signal wave, and the numerical relativistic waveform of the GW150914 signal wave deviates too far from the original waveform actually. Other LIGO signal waveforms do not have obvious characteristics of gravitational frequency variation of spiral binary stars and lack precise data, so they cannot be used for numerical analysis and image solution. Therefore, LIGO signals represented by gw50914 signal do not support the relativistic gravitational wave frequency equation. However, whether gravitational wave signals from spiral binaries that may be detected in the future follow the same co quantization law? The answer is not clear at present.


Author(s):  
XD Dongfang

Signal waves of the monotone increasing frequency detected by LIGO are universally considered to be gravitational waves of spiral binary stars, and the general theory of relativity is thus universally considered to have been confirmed by the experiments. Here we present a universal method for signal wave spectrum analysis, introducing the true conclusions of numerical calculation and image analysis of GW150914 signal wave. Firstly, numerical calculation results of GW150914 signal wave frequency change rate obey the com quantization law which needs to be accurately described by integers, and there is an irreconcilable difference between the results and the generalized relativistic frequency equation of the gravitational wave. Secondly, the assignment of the frequency and frequency change rate of GW10914 signal wave to the generalized relativistic frequency equation of gravitational wave constructs a non-linear equation group about the mass of wave source, and the computer image solution shows that the equation group has no GW10914 signal wave solution. Thirdly, it is not unique to calculate the chirp mass of the wave source from the different frequencies and change rates of the numerical relativistic waveform of the GW150914 signal wave, and the numerical relativistic waveform of the GW150914 signal wave deviates too far from the original waveform actually. Other LIGO signal waveforms do not have obvious characteristics of gravitational frequency variation of spiral binary stars and lack precise data, so they cannot be used for numerical analysis and image solution. Therefore, LIGO signals represented by gw50914 signal do not support the relativistic gravitational wave frequency equation. However, whether gravitational wave signals from spiral binaries that may be detected in the future follow the same co quantization law? The answer is not clear at present.


Author(s):  
XD Dongfang

Signal waves of the monotone increasing frequency detected by LIGO are universally considered to be gravitational waves of spiral binary stars, and the general theory of relativity is thus universally considered to have been confirmed by the experiments. Here we present a universal method for signal wave spectrum analysis, introducing the true conclusions of numerical calculation and image analysis of GW150914 signal wave. Firstly, numerical calculation results of GW150914 signal wave frequency change rate obey the com quantization law which needs to be accurately described by integers, and there is an irreconcilable difference between the results and the generalized relativistic frequency equation of the gravitational wave. Secondly, the assignment of the frequency and frequency change rate of GW10914 signal wave to the generalized relativistic frequency equation of gravitational wave constructs a non-linear equation group about the mass of wave source, and the computer image solution shows that the equation group has no GW10914 signal wave solution. Thirdly, it is not unique to calculate the chirp mass of the wave source from the different frequencies and change rates of the numerical relativistic waveform of the GW150914 signal wave, and the numerical relativistic waveform of the GW150914 signal wave deviates too far from the original waveform actually. Other LIGO signal waveforms do not have obvious characteristics of gravitational frequency variation of spiral binary stars and lack precise data, so they cannot be used for numerical analysis and image solution. Therefore, LIGO signals represented by gw50914 signal do not support the relativistic gravitational wave frequency equation. However, whether gravitational wave signals from spiral binaries that may be detected in the future follow the same co quantization law? The answer is not clear at present.


2021 ◽  
Vol 27 (1) ◽  
pp. 49-54
Author(s):  
Samir Ezequiel da Rosa ◽  
Amina Chain Costa ◽  
Marcos de Sá do Rego Fortes ◽  
Runer Augusto Marson ◽  
Eduardo Borba Neves ◽  
...  

ABSTRACT Introduction It has been suggested that visceral adipose tissue (VAT) is associated with several non-communicable chronic diseases, but measuring it is difficult. Thus, anthropometry could be used because is easily applied in clinical practice. Objectives The present study aimed to develop and validate VAT estimation equations (Eq) in military men. Methods The sample consisted of 409 (mean age, 36.5 ± 6.7 years) military men in the Brazilian Army (BA) divided into an equation group (EG) ( n = 270; mean age, 37.0 ± 6.3 years) and a validation group (VG) ( n =139; mean age, 36.0 ± 7.2 years). Anthropometric, hemodynamic and DXA body composition evaluations ( GE iLunar ) were performed. The Student’s t test, Pearson’s correlation, and stepwise general linear regression were applied. Bland-Altman graphics were used to assess the concordance between VAT by Eq and by DXA. The level of significance was 95% ( p < 0.05). Results Age, waist circumference (WC), hip circumference and body mass index presented the main significant positive correlations with the VAT-DXA. Four Eq were created Eq1 ( r 2 = 0.793), Eq2 ( r 2 = 0.810), Eq3 ( r 2 = 0.817), and Eq 4 ( r 2 = 0.823) ( p < 0.05). No differences were observed between VAT by DXA and VAT by Eq ( p = 0.982, p = 0.970, p = 0.495 and p = 0.698). Bland-Altman analysis also presented good concordance as the bias was close to zero and was not statistically significant. Conclusion Eq2 (age*13.0 + WC*60.0 - 4975,.5) was more suitable because it is easier to apply, has a higher predictive power (81.0%), less bias (1.86) and validation yielded average VAT values close to those found in DXA. It may still be considered a valuable tool for other extensive epidemiological studies in military men in the BA and can be used in adult men. Evidence Level I: Development of diagnostic criteria on consecutive patients (with universally applied reference ‘‘gold’’ standard).


2018 ◽  
Vol 14 (06) ◽  
pp. 1573-1604
Author(s):  
Alexander Dahl

We study a double Dirichlet series of the form [Formula: see text], where [Formula: see text] and [Formula: see text] are quadratic Dirichlet characters with prime conductors [Formula: see text] and [Formula: see text] respectively. A functional equation group isomorphic to the dihedral group of order 6 continues the function meromorphically to [Formula: see text]. The developed theory is used to prove an upper bound for the smallest positive integer [Formula: see text] such that [Formula: see text] does not vanish. Additionally, a convexity bound at the central point is established to be [Formula: see text] and a subconvexity bound of [Formula: see text] is proven. An application of bounds at the central point to the non-vanishing problem is also discussed.


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