With the rapid increase of energy demand and the increasingly highlighted environmental problems, clean, safe and widely distributed geothermal resources have become a hot spot for renewable resources development. The...With the rapid increase of energy demand and the increasingly highlighted environmental problems, clean, safe and widely distributed geothermal resources have become a hot spot for renewable resources development. The state of in-situ stress is a major control parameter for multiple links including well location, fracture inspiration and reservoir assessment, so how to determine the accurate state of in-situ stress in the deep thermal reservoir becomes a core problem drawing widely attention and urgent to be solved. Based on features of hot dry rock reservoir in terms of temperature and pressure and the comparison analysis, this article proposes the method of Anelastic Strain Recovery(ASR) as an effective method for determining the state of in-situ stress in the area with HDR resources distributed and explains the availability of ASR method by application examples.展开更多
Grating-based x-ray phase contrast imaging has the potential to be applied in future medical applications as it is compatible with both laboratory and synchrotron source. However, information retrieval methods are imp...Grating-based x-ray phase contrast imaging has the potential to be applied in future medical applications as it is compatible with both laboratory and synchrotron source. However, information retrieval methods are important because acquisition speed, scanning mode, image quality, and radiation dose depend on them. Phase-stepping(PS) is a widely used method to retrieve information, while angular signal radiography(ASR) is a newly established method. In this manuscript,signal-to-noise ratios(SNRs) of ASR are compared with that of PS. Numerical experiments are performed to validate theoretical results. SNRs comparison shows that for refraction and scattering images ASR has higher SNR than PS method,while for absorption image both methods have same SNR. Therefore, our conclusions would have guideline in future preclinical and clinical applications.展开更多
This paper is, in fact, a proposal of a polynomial approach to the nonlinear systems control by using the concept of linearization by state feedback. In this context, a discretization method is presented. We developed...This paper is, in fact, a proposal of a polynomial approach to the nonlinear systems control by using the concept of linearization by state feedback. In this context, a discretization method is presented. We developed a discrete control scheme based on an approximate feedback linearization method and the reversing trajectory method. The proposed control strategy sits on the methods of widening the stability domains of operating points. Such domains are expanded through the use of the non Lyapunov stability synthesis methods. Additionally, the developed technique is employed for the control of the class of systems with an order higher than two;more precisely, the example of a synchronous generator featured in a strongly nonlinear model.展开更多
In this paper, the variable structure control method is improved. Based on the existence and the reaching conditions for the auto-stable region of two-order systems, a new synthesis method, auto-stable region approach...In this paper, the variable structure control method is improved. Based on the existence and the reaching conditions for the auto-stable region of two-order systems, a new synthesis method, auto-stable region approach is presented to construct a global stabilizing feedback law by using a positive definite function and a properly selected saturated function. This new approach is robust with respect to the bounded model uncertainties and is convenient for both analysis and engineering implemelltation.展开更多
基金founded by Project of National Natural Science Foundation of China “Study on the Anelastic Strain Recovery Compliance in the In-situ Stress Measurement by ASR Method”, No 41404080the Project of Geological Survey “Survey on the In-situ Stress Field in Southern China”
文摘With the rapid increase of energy demand and the increasingly highlighted environmental problems, clean, safe and widely distributed geothermal resources have become a hot spot for renewable resources development. The state of in-situ stress is a major control parameter for multiple links including well location, fracture inspiration and reservoir assessment, so how to determine the accurate state of in-situ stress in the deep thermal reservoir becomes a core problem drawing widely attention and urgent to be solved. Based on features of hot dry rock reservoir in terms of temperature and pressure and the comparison analysis, this article proposes the method of Anelastic Strain Recovery(ASR) as an effective method for determining the state of in-situ stress in the area with HDR resources distributed and explains the availability of ASR method by application examples.
基金Project supported by the National Research and Development Project for Key Scientific Instruments(Grant No.CZBZDYZ20140002)the National Natural Science Foundation of China(Grant Nos.11535015,11305173,and 11375225)+2 种基金the project supported by Institute of High Energy Physics,Chinese Academy of Sciences(Grant No.Y4545320Y2)the Fundamental Research Funds for the Central Universities(Grant No.WK2310000065)Wali Faiz,acknowledges and wishes to thank the Chinese Academy of Sciences and The World Academy of Sciences(CAS-TWAS)President’s Fellowship Program for generous financial support
文摘Grating-based x-ray phase contrast imaging has the potential to be applied in future medical applications as it is compatible with both laboratory and synchrotron source. However, information retrieval methods are important because acquisition speed, scanning mode, image quality, and radiation dose depend on them. Phase-stepping(PS) is a widely used method to retrieve information, while angular signal radiography(ASR) is a newly established method. In this manuscript,signal-to-noise ratios(SNRs) of ASR are compared with that of PS. Numerical experiments are performed to validate theoretical results. SNRs comparison shows that for refraction and scattering images ASR has higher SNR than PS method,while for absorption image both methods have same SNR. Therefore, our conclusions would have guideline in future preclinical and clinical applications.
文摘This paper is, in fact, a proposal of a polynomial approach to the nonlinear systems control by using the concept of linearization by state feedback. In this context, a discretization method is presented. We developed a discrete control scheme based on an approximate feedback linearization method and the reversing trajectory method. The proposed control strategy sits on the methods of widening the stability domains of operating points. Such domains are expanded through the use of the non Lyapunov stability synthesis methods. Additionally, the developed technique is employed for the control of the class of systems with an order higher than two;more precisely, the example of a synchronous generator featured in a strongly nonlinear model.
文摘In this paper, the variable structure control method is improved. Based on the existence and the reaching conditions for the auto-stable region of two-order systems, a new synthesis method, auto-stable region approach is presented to construct a global stabilizing feedback law by using a positive definite function and a properly selected saturated function. This new approach is robust with respect to the bounded model uncertainties and is convenient for both analysis and engineering implemelltation.
